MEM47 Automotive Project
Investigation of Control System Strategies for
Hydraulic Valve Actuation in an IC Engine
Adil Karakayis
1st September 2014
Supervisor: Dr Steven Begg
University of Brighton School of Computing, Engineering and Mathematics, Division of
Engineering & Product Design
Word Count: 13259
MSc Automotive Engineering Page 1 of 93 Adil Karakayis
Disclaimer
“I certify that the attached dissertation is my own work except where otherwise indicated. I have
referenced my sources of information; in particular I have placed quotation marks before and after
any passages that have been quoted word-for-word, and identified their origins.
I give my consent that hard-copy and soft-copy of this dissertation can be made available in full for
subsequent students taking this module.”
____________________ ____________________
SIGN DATE
MSc Automotive Engineering Page 2 of 93 Adil Karakayis
Abstract
Flexible control of valve lifting, timing and duration makes possible to do significant reduction of
fuel consumption and exhaust emission. Although it is possible to change valve lifting, timing and
duration with camshaft based variable valve actuation systems, they have restriction of camshaft
profile and no valve independency. Electro hydraulic valve actuation systems aim to optimize the
restrictive camshaft profile and give independency of each valve to render possible advance internal
combustion engine strategies. In this project, single electro hydraulic valve actuation system is used
to investigate MATLAB based feed-forward control system. MATLAB/Simulink Simscape library
components which are SimMechanics and SimHydraulics are used to simulate whole test rig because
pre-calculations are necessary for the feed-forward control system. Therefore, simulation model is
used to calculate a signal form for servovalve of hydraulic actuator according to engine speed and
valve lift profile. At the beginning camshaft profile is followed by electro hydraulic actuator system
to prove that this system has capable of existing mechanical systems. After that this camshaft profile
is optimized by using basic equations of volumetric efficiency and considering air choking conditions
according to piston speed. Experiments were repeated with the optimized valve lift profile.
Experiments were done from 800 rpm to 6000rpm at 70bar oil pressure. Even though the experiment
results are promising, if the simulation model and signal generation system is going to be improved,
results might be better for feed-forward control system.
MSc Automotive Engineering Page 3 of 93 Adil Karakayis
Table of Contents
Acknowledgement ......................................................................................................................... 9
Abbreviations ................................................................................................................................ 10
Introduction ................................................................................................................................... 12
1- Valve Actuation Systems ...................................................................................................... 13
1.1- Mechanical Valve Actuation System ........................................................................... 13
1.1.1- Design of Camshaft .................................................................................................. 14
1.1.2- Cam Changing and Cam Phasing Systems ....................................................... 16
1.1.3- Continuously Variable Valve Lifting Systems ................................................... 20
1.2- Electro Hydraulic Valve Actuation Systems ............................................................. 22
1.3- Summary of Existing Systems ..................................................................................... 25
2- Structure of Test Rig .............................................................................................................. 26
2.1- Modification of Test Rig ................................................................................................. 27
2.2- Test Rig Equipment ......................................................................................................... 29
2.2.1- Oil Tank ....................................................................................................................... 31
2.2.2- Hydraulic Pump and Electrical Motor .................................................................. 31
2.2.3- Accumulator ............................................................................................................... 32
2.2.4- Oil Filter ....................................................................................................................... 32
2.2.5- Pressure Switch ........................................................................................................ 32
2.2.6- Moog Servovalve ...................................................................................................... 33
2.2.7- Hydraulic Valve Actuator Assembly .................................................................... 34
2.2.8- Pressure Transducer Flange ................................................................................. 37
2.2.9- Poppet Valve .............................................................................................................. 38
2.2.10- Control Box .............................................................................................................. 38
2.2.11- Main Electrical Box ................................................................................................ 39
2.3- Oil Properties .................................................................................................................... 39
2.4- Signal Generation System ............................................................................................. 39
2.4.1- Arduino Mega 2560 ................................................................................................... 40
2.4.2- Function Generator .................................................................................................. 43
2.4.3- Signal Amplifier ......................................................................................................... 44
2.5- Data Logging System ...................................................................................................... 44
2.5.1- Pressure Transducers and Charge Amplifiers ................................................. 44
2.5.2- Linear Variable Differential Transformer and Signal Conditioner ............... 45
2.5.3- Oscilloscope and Picoscope ................................................................................. 45
2.6- Test Rig Restrictions ....................................................................................................... 46
MSc Automotive Engineering Page 4 of 93 Adil Karakayis
3- MATLAB/Simulink Simulation Model ................................................................................. 47
3.1- SimMechanics ................................................................................................................... 48
3.2- SimHydraulics ................................................................................................................... 50
3.2.1- Hydraulic Fluid .......................................................................................................... 52
3.2.2- Hydraulic Pump ......................................................................................................... 52
3.2.3- Accumulator ............................................................................................................... 52
3.2.4- 4-Way Directional Valve .......................................................................................... 52
3.2.5- Optimization Tool for 4-Way Directional Valve ................................................. 55
3.2.6- Double-Acting Hydraulic Cylinder ........................................................................ 56
3.3- Control System ................................................................................................................. 57
4- Method of Experiments .......................................................................................................... 58
4.1- V-tec Camshaft Profile .................................................................................................... 60
4.2- Desired Valve Lift Profile................................................................................................ 61
5- Experiment Results and Analysis ....................................................................................... 63
5.1- Discussion of Experiment Results .............................................................................. 71
6- Future Work .............................................................................................................................. 72
Conclusion ..................................................................................................................................... 74
References ..................................................................................................................................... 75
Appendix A .................................................................................................................................... 80
Appendix B .................................................................................................................................... 91
Appendix C .................................................................................................................................... 92
MSc Automotive Engineering Page 5 of 93 Adil Karakayis
MSc Automotive Engineering Page 6 of 93 Adil Karakayis
MSc Automotive Engineering Page 7 of 93 Adil Karakayis
MSc Automotive Engineering Page 8 of 93 Adil Karakayis
MSc Automotive Engineering Page 9 of 93 Adil Karakayis
Acknowledgement
I want to express my sincere gratitude to Dr Steven Begg who gave me that opportunity to do
investigation of control system strategies for hydraulic valve actuation in an internal combustion
engine. I would like to thank Mr Peter Rayner, Mr Mario Palermo and Mr Jon Armory who are SHRL
technicians for their assistance to finish test rig as fast as possible. I am truly grateful to Dr Chris
Garrett, Dr Daniel Coren and Dr Guillaume de Sercey for their support on this project. Finally, I
thank my family for their encouragements.
MSc Automotive Engineering Page 10 of 93 Adil Karakayis
Abbreviations
LVDT: Linear variable differential transformer
PWM: Pulse Width Modulation
DAHC: Double-acting hydraulic cylinder
4WDV: 4-way directional valve
IC: Internal combustion
EHVA: Electro hydraulic actuation
VVT: Variable valve timing
VVTL-i: Variable Valve Timing and Lifting with Intelligence
i-VTEC: Intelligent Variable Valve Timing and Electronic Lift Control
IVLC: Intake Valve Lift Control
VVEL: Variable Valve Event and Lift
MAEHV: Multi-Air Electro Hydraulic Valve Timing
PID: Proportional-Integral-Derivative
𝐴𝐸̅̅̅̅ : 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑒𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝑖𝑛𝑡𝑎𝑘𝑒 𝑓𝑙𝑜𝑤 𝑎𝑟𝑒𝑎
𝜃𝑖𝑐: 𝐼𝑛𝑡𝑎𝑘𝑒 𝑣𝑎𝑙𝑣𝑒 𝑐𝑙𝑜𝑠𝑖𝑛𝑔 𝑎𝑛𝑔𝑙𝑒 (𝑟𝑎𝑑)
𝜃𝑖𝑜: 𝐼𝑛𝑡𝑎𝑘𝑒 𝑣𝑎𝑙𝑣𝑒 𝑜𝑝𝑒𝑛𝑖𝑛𝑔 𝑎𝑛𝑔𝑙𝑒 (𝑟𝑎𝑑)
𝐶�̅�: 𝐷𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒𝑟 𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑤ℎ𝑖𝑐ℎ 𝑖𝑠 𝑎𝑠𝑠𝑢𝑚𝑒𝑑 0.6
𝑍: 𝑀𝑒𝑎𝑛 𝑀𝑎𝑐ℎ 𝑛𝑢𝑚𝑏𝑒𝑟 𝑎𝑡 𝑖𝑛𝑙𝑒𝑡 𝑡ℎ𝑟𝑜𝑎𝑡
𝐴𝑝: 𝑃𝑖𝑠𝑡𝑜𝑛 𝑎𝑟𝑒𝑎
𝑆�̅�: 𝑃𝑖𝑠𝑡𝑜𝑛 𝑚𝑒𝑎𝑛 𝑠𝑝𝑒𝑒𝑑
𝑐𝑖: 𝑠𝑜𝑢𝑛𝑑 𝑠𝑝𝑒𝑒𝑑 𝑎𝑡 𝑖𝑛𝑙𝑒𝑡
𝑒𝑣: 𝑉𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑖𝑐 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦
𝑚𝑖: 𝑀𝑎𝑠𝑠 𝑖𝑛𝑑𝑢𝑐𝑒𝑑 𝑑𝑢𝑟𝑖𝑛𝑔 𝑣𝑎𝑙𝑣𝑒 𝑜𝑝𝑒𝑛 𝑡𝑖𝑚𝑒
𝜌𝑖: 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑎𝑖𝑟 𝑎𝑡 𝑖𝑛𝑙𝑒𝑡 𝑚𝑎𝑛𝑖𝑓𝑜𝑙𝑑
𝑉𝑑: 𝐷𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑒𝑛𝑔𝑖𝑛𝑒
𝜔: 𝐸𝑛𝑔𝑖𝑛𝑒 𝑠𝑝𝑒𝑒𝑑 (rpm)
𝐴𝐶 : 𝑉𝑎𝑙𝑣𝑒 𝑐𝑢𝑟𝑡𝑎𝑖𝑛 𝑎𝑟𝑒𝑎
𝐷𝑣: 𝑉𝑎𝑙𝑣𝑒 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟
𝐿𝑣: 𝐿𝑖𝑓𝑡 𝑜𝑓 𝑣𝑎𝑙𝑣𝑒
ᵧ: 𝐻𝑒𝑎𝑡 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 𝑟𝑎𝑡𝑖𝑜 𝑤ℎ𝑖𝑐ℎ 𝑖𝑠 𝑎𝑠𝑠𝑢𝑚𝑒𝑑 1.4
MSc Automotive Engineering Page 11 of 93 Adil Karakayis
𝑅: 𝐼𝑑𝑒𝑎𝑙 𝑔𝑎𝑠 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 (287 𝑗
𝑘𝑔𝐾⁄ )
𝑇𝑜: 𝐴𝑖𝑟 𝑡𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 𝑎𝑡 𝑖𝑛𝑙𝑒𝑡 𝑚𝑎𝑛𝑖𝑓𝑜𝑙𝑑 300K
𝑁: 𝐸𝑛𝑔𝑖𝑛𝑒 𝑠𝑝𝑒𝑒𝑑 (𝑟𝑝𝑠)
D: Displacement of the poppet valve (mm)
M: Slope of LVDT sensor (mm/V)
X: Sensor output voltage (V)
𝑑: 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑡ℎ𝑒 𝑐 𝑦𝑙𝑖𝑛𝑑𝑒𝑟
l: Actuator rod piston length
δ: 𝑅𝑒𝑐𝑖𝑝𝑟𝑜𝑐𝑎𝑙
b: Viscous damping coefficient of hydraulic cylinder
𝜌: Density of hydraulic fluid
v: kinematic viscosity of hydraulic fluid
q: Flow rate through the orifice
𝐶𝑑: Flow discharge coefficient
A: Orifice area
𝐴𝑚𝑎𝑥: Maximum orifice area
h: Orifice opening
ℎ0: Initial opening of the spool
ℎ𝑚𝑎𝑥: Maximum orifice opening
x: Control member displacement (spool)
P: Pressure
𝜃𝐶: Crankshaft angle
s:Piston stroke
a: Crankshaft radius
l:Connecting rod length
MSc Automotive Engineering Page 12 of 93 Adil Karakayis
Introduction
Efficiency of conventional four-stroke IC engines are getting better while researches continuous. As
new research techniques arise such as optical diagnostic techniques, it becomes possible to look at
inside the combustion chamber which allows researchers to visualize swirl ratio and tumble ratio to
create better air-fuel mixture. These researches illustrates and proves the importance of inlet valve
operations for volumetric efficiency and exhaust valve operations for exhaust scavenging of the IC
engine. As a result of increasing of emission regulations, limits of the engine efficiencies are forced.
IC engines require more complex valve operation systems for better fuel economy and lower exhaust
emission with the improvement of new fuel injection systems such as gasoline direct injection after
port injection system. As a result of mechanically certain design of cam lobe, valve is restricted to
follow that camshaft profile. Although it is possible to improve the restrictive cam profile with cam
phasing and valve lifting which are integrated onto mechanical valve actuation systems, it still has
restriction of the camshaft profile design. Moreover, it is required to have independence for each
valve to move one step further the engine efficiencies. Freedom of valves will allow researchers to
control swirl ratio better for creating homogenous mixture with highly atomized fuel. Even
volumetric efficiency of IC engines can be increased by using forced induction systems such as
turbocharger and supercharger, independence of valve is still required to control swirl ratio. With
EHVA system, inlet and exhaust valves can be controlled by engineers with wide variety of control
strategies to optimise IC engines volumetric efficiency and exhaust scavenging. It makes possible to
do any kind of profile shape in the inlet and exhaust strokes. EHVA system is removed restrictions
of mechanical actuation systems until the formed their own restrictions. Limitations of this system is
clearly explained below. In this project, all experiments are done for the inlet valve profile which is
the most important valve for IC engines. First of all, existing Vtec full lift camshaft profile for B15C7
engine is followed. Secondly, this profile is optimised for that specific engine and all experiments
are done for that optimised profile also. MATLAB/Simulink is used to create a simulation model of
complete system which generates a feed-forward signal for servovalve at each determined engine
speed. Experiments were done for 800, 1000, 1500, 2000, 2500, 3000, 4000, 5000, 6000rpm engine
MSc Automotive Engineering Page 13 of 93 Adil Karakayis
speeds in the pressure range of 68 to 72bar. As a result of experiments, this system has been
successful up to 2500rpm at that pressure range.
1- Valve Actuation Systems
Conventional IC engines have mechanically actuated valves which are controlled by a camshaft since
they are designed. Even though they work very well, they have limitations for camshaft profiles
which effects volumetric efficiency. This limitation is result of cam lobe design because it actuates
valves in linear motion but camshaft is a rotational part. Therefore, cam lobe should have eccentric
shape. Although camshaft restrictions can be improved by using cam phasing for valve overlapping
and valve lifting systems, valve opening profile is still constraint by cam lobe profile. A lot of
research is continuing on electromagnetic and electrohydraulic valve actuation systems which
removes limitations of mechanically actuated valve systems. These systems eliminate dependency
of camshaft profile and gives freedom for each valve. Therefore, they enable infinitely flexible
control for valve lifting, duration and variable timing.
1.1- Mechanical Valve Actuation System
Working principle of mechanical valve actuation system on four-stroke engine is that turning
camshaft pulley by using timing belt or gear mechanism which is attached to the crankshaft pulley
or gear. As the piston moves downwards in the intake stroke, crankshaft rotates, hence camshaft
rotates which is attached to the crankshaft. Therefore, cam lobes pushes valves to open. While piton
moves downwards, it sucks the air trough intake ports and opened intake valves. When the piston
moves upwards at exhaust stroke same event happens to open exhaust valve [1]. Valves control the
air/fuel or just air flow and exhaust scavenging so timing of this process has critical importance to
fill the cylinder with fresh air without choking and remove the exhaust gasses efficiently. Basic
mechanical valve actuation system is illustrated in the figure.1.
MSc Automotive Engineering Page 14 of 93 Adil Karakayis
Figure.1 Mechanical valve actuation system [3]
1.1.1- Design of Camshaft
Camshaft design should be considered early design of IC engines to get optimized engine
performance, fuel consumption and exhaust emission. Unique timing characteristics is necessary to
have maximum engine performance with high efficiency. However, it is hard to optimise both which
means while performance is at maximum, fuel consumption is high. Otherwise, when the fuel
consumption is reduced, performance also reduces. When costumers purchase an automobile, they
want both of them are optimised which is not possible with fixed design camshafts. In response to
this problem, manufacturers have been attempting to produce variable valve timing systems such as
cam phasing and valve lifting systems [2]. Typical camshaft profile is given in the figure.2. Cam
lobe opening and closing ramps are designed smoothly so the valve opening and landing becomes
gently. Relation of the cam lobe and valve opening profile can be seen in the figures 2 and 3.
MSc Automotive Engineering Page 15 of 93 Adil Karakayis
Figure.2 Typical cam lobe profile [4]
Figure.3 Typical camshaft profile [5]
MSc Automotive Engineering Page 16 of 93 Adil Karakayis
1.1.2- Cam Changing and Cam Phasing Systems
There are two types VVT systems which are valve lifting and cam phasing systems. They can be
categorized to discrete and continuously systems. Cam changing and some cam phasing systems are
in discrete systems. VVT systems are mostly mechanical designs. Therefore, although these systems
remove the fixed valve timing and duration limitation, they have limited range to change them.
Volumetric efficiency equations illustrates that VVT systems are necessarily to change valve lifting
and cam phasing during engine speed increases [14].
Figure.4 Poppet valve geometry [15]
�̅�𝐸 =1
𝜃𝑖𝑐−𝜃𝑖𝑜∫ 𝐴𝐸 𝑑𝜃 = 𝐶�̅�𝐴𝐶
𝜃𝑖𝑐
𝜃𝑖𝑜 …1
𝐴𝐶 = 𝜋𝐷𝑣𝐿𝑣 …2
𝐴𝑝 = 2𝜋𝑟2 …3
𝑍 =𝐴𝑝�̅�𝑝
𝐴𝐸𝑐𝑖 …4
𝑆�̅� = 2𝑠𝑁 …5
𝑐𝑖 = √ᵧ𝑅𝑇0 …6
𝑒𝑣 = 𝑚𝑖
𝜌𝑖𝑉𝑑=
1
𝜔𝜌𝑖𝑉𝑑∫ �̇�𝑑𝜃
𝜃𝑖𝑐
𝜃𝑖𝑜 …7
𝑒𝑣 =�̅�𝐸𝑐𝑖
𝜔𝑉𝑑(𝜃𝑖𝑐 − 𝜃𝑖𝑜) (
2
ᵧ+1)
(ᵧ+1)/2(ᵧ−1) …8
𝑒𝑣 = 0.58 (𝜃𝑖𝑐−𝜃𝑖𝑜
𝜋)
1
𝑧 …9
MSc Automotive Engineering Page 17 of 93 Adil Karakayis
There is always a limiting case which flow chokes if valve lift and timing does not synchronised very
well with piston speed. According to that if choked flow is the top level for the flow, volumetric
efficiency can be calculated by using equation.8. These equations were used to calculate optimized
profiles according to engine speed in section 4.2 for EHVA system also. With respect to equation.8,
opening angle, duration time and valve lifting is affected by piston speed for the volumetric
efficiency. In response to this situation, each manufacturer has VVT systems with different names
and small changes. Even though they have different names, working principle is same for all of them.
VVTL-i and i-VTEC are examples for continuously variable cam phasing systems. All cam changing
systems are discrete valve lifting systems. VarioCam and next generation VarioCam Plus are
produced by Porsche Company. Volkswagen group cars are also used this system on 1.8t engines.
VarioCam system does cam phasing by changing the position of tensioners with the help of hydraulic
cylinder (figure.5) [6].
Figure.5 VarioCam cam phasing system [6]
VarioCam Plus does cam phasing by changing cam pulley and camshaft phase angle. This event
happens by forcing helical gear to move in liner motion with hydraulic pressure which changes phase
angle (figure.6). VarioCam Plus has cam changing system also which enables to change valve lifting.
MSc Automotive Engineering Page 18 of 93 Adil Karakayis
In this system, camshaft has two different cam lobe profile. One of them is for low lifting profile and
the other one is for high lifting profile [7].
Figure.6 VarioCam Plus and Vanos cam phasing system [6]
In the VarioCam Plus system, by changing cam lobe, two different valve profile can be followed
according to engine speed (figure.7). Changing cam makes possible to switch two different cam lobes
discretely which have different opening duration and valve lift. Variable hydraulic tappets are used
to change these two lobes. Transition can be provided by changing the contact of lobes from inner
tappet to outer tappet which can be done by locking a hydraulically actuated pin. In addition to
VarioCam Plus, Vanos cam phasing system which has same working principle is used by BMW car
manufacturer (figure.6). Hydraulic pressure on the piston changes the phase angle in between the
cam pulley and camshaft by rotating the helical gear, when it is actuated by a solenoid valve [7].
Figure.7 VarioCam Plus cam phasing system and valve lifting mechanism [7]
MSc Automotive Engineering Page 19 of 93 Adil Karakayis
Moreover, Toyota uses VVTL-i which is sophisticate variable valve timing system. This system is
the combination of VVT-i and V-TEC. The difference of VVTL-i is just lifting mechanism. Shifting
the whole camshaft phase angle is possible with VVT-i system. In this system, cam phasing
mechanism is placed into the camshaft pulley which changes cam pulley and stator phase angle by
just controlling hydraulic pressure. Engine oil fills into the stator oil channels and changes the phase
angle with cam pulley. Honda uses i-VTEC which is similar to VVTL-i system (figure.8). These two
systems enable continuously cam phasing which gives flexibility to control cam phasing from low
to high engine speeds [7].
Figure.8 i-VTEC cam phasing system [9]
Figure.9 VVTL-i valve lifting mechanism [7]
MSc Automotive Engineering Page 20 of 93 Adil Karakayis
VVTL-i uses single rocker system similar to V-TEC mechanism with some design differences
(figure.9). There are two different cam lobes as VarioCam Plus system. Difference of this system is
that rocker follows lower profile at low engine speed and other lobe rotates freely. While engine
speed increases hydraulically actuated pin locks the rocker arm to follow higher cam lobe. Rocker
arm activation/de-activation is used by many other manufacturer also. For instance, V-TEC and GM
IVLC. Although i-VTEC has similar system, it has three stages cam lobes which are low, medium
and high lift cam lobe profiles. Audi valve lifting system is another design for valve lifting which
has two stages with three different cam lobes. Transition occurs by sliding camshaft with actuator
rod and grove on the camshaft (figure.10). Mercedes Camtronic system is similar to the Audi valve
lifting system [7].
Figure.10 Audi valvelift mechanism [11]
1.1.3- Continuously Variable Valve Lifting Systems
With the improvement of the VVT technology, continuously valve lifting systems have been
developed such as BMW Valvetronic, Toyota Valvematic and Nissan VVEL systems. Valvetronic
system is the first continuous variable valve lifting system in the world. Working principle of this
system is that additional electric motor rotates eccentric shaft to push the secondary rocker arm which
MSc Automotive Engineering Page 21 of 93 Adil Karakayis
opens valve more variably (figure.11). Therefore, valve lift displacement can be controlled
continuously by just rotating eccentric shaft [7].
Figure.11 BMW Valvetronic system [7]
In Toyota Valvematic system, although the design is different from BMW Valvetronic system,
working principle is same. While intermediate shaft rotates to have wide angle, valve lift becomes
high lift (figure.12) [7].
Figure.12 Toyota Valvematic system [7]
MSc Automotive Engineering Page 22 of 93 Adil Karakayis
VVEL system is another design by Nissan which does same job with other continuous valve lifting
systems. When control shaft rotates by electric motor because of it has eccentric shape, it pushes
output cam to change the lift of valve (figure.13) [7].
Figure.13 Toyota Valvematic system [7]
1.2- Electro Hydraulic Valve Actuation Systems
There are camless engines and hybrid systems which combines both systems. In the nutshell, camless
engines have electrohydraulic or electromagnetic systems which have capable of all camshaft
systems and more to do valve lifting and cam phasing. Although hybrid systems have semi-
independence for the valves, they still have restrictions of the camshaft profile. Thus, fully EHVA
systems are developed for full independency of each valve. It enables to control each valve with
different profiles if it is necessary. Even though there are lots of researches on the fully EHVA
systems, they are not on the production line yet. However, hybrid system such as MAEHV system
which is developed by Fiat is on production cars. As it can be seen in the figure.14, this system can
achieve five different strategies which are full lift, late intake valve opening, early valve closing,
partial load and even multi lift. Firstly, full lift is conventional cam control which follows rigid cam
profile. It is suitable for high engine speed. In second strategy, late intake valve opening is obtained
MSc Automotive Engineering Page 23 of 93 Adil Karakayis
by electronic hydraulic solenoid valve which respects to the cam profile. This strategy is suitable for
low load conditions. Early valve closing allows to anticipate the intake valve closing time which is
suitable for part load operations. Fourth strategy gives possibility of closing intake valve earlier to
prevent air escape to intake manifold. This strategy is done to improve acceleration at low engine
speed. Final mode enables the possibility of multi valve lift in the intake stroke. This strategy is the
combination of second and third strategies to regulate consumption while increase the performance
at low engine speed [7].
Figure.14 Fiat Multi-Air system [7]
Cam-Camless Eaton design is also hybrid system which allows to do different valve profile strategies
for camless system. Possible strategies of this system are given in the figure.16 where can be seen
wide variety of strategies are possible to be generated with camless system in addition to mechanical
system benefits [11].
MSc Automotive Engineering Page 24 of 93 Adil Karakayis
Figure.15 Eaton cam-camless hybrid system [11]
Figure.16 Eaton cam-camless hybrid system strategies [11]
Furthermore, Ricardo Company has been developed camless HYDRA single cylinder research
engine with electro-hydraulic valvetrain system which enables flexibility of continuously variable
valve timing and lifting, variable opening and closing rate, multiple events, port deactivation and
MSc Automotive Engineering Page 25 of 93 Adil Karakayis
variable valve profile [12]. Additionaly, in 2009, with the cooperation of Lotus and Eaton, active
valve train system is produced which is fully VVT system with AVT actuator. Similarly, Ricardo
uses this type actuator with servovalve. This system is controlled by a closed loop system. Currently,
the system makes possible advance engine strategies such as homogenous charge compression
ignition, without throttle operations to eliminate throttling losses, variable firing order, possible fast
start, ultimately air hybridisation and differential cylinder loading [13].
Figure.17 Valve Block of Research AVT Actuator [13]
1.3- Summary of Existing Systems
All mechanical systems can be applied on both inlet and exhaust camshaft. However, as it can be
seen in the figure.3, although Valvetronic, Valvematic and VVEL have ability to alter valve lift
infinitely according to the requirements of engine in addition to continuously variable cam phasing,
valves are still restricted to follow the cam lobe profile. Unlimited flexibility is not possible for
different valve strategies in mechanical systems. However, EHVA systems offer infinite variations
of continuously variable and independent valve control. Which enables different strategies of valve
openings, timings and profiles. With the improvement of all these variations, as it explained above,
it allows engineers to develop advanced engine strategies. In next chapters, EHVA system
MATLAB/Simulink based feed-forward control strategy is tested to enable all these advance engine
strategies.
MSc Automotive Engineering Page 26 of 93 Adil Karakayis
2- Structure of Test Rig
Figure.18 Diagram of the complete setup
MSc Automotive Engineering Page 27 of 93 Adil Karakayis
Electro hydraulic valve actuation test rig was designed to do all determined experiments for
generating desired valve profile. In this test rig, hydraulic pump is controlled by a control box for oil
pressure supply. This oil pressure is kept constant by an on/off closed loop control system which is
controlled by a pressure switch. Moreover, all data are saved by a picoscope. Furthermore, complete
test rig is simulated into a MATLAB/Simulink model to create signal form for a servovalve.
This simulated signal form for the servovalve is generated by a function generator when it
is triggered by a triggering button to control the poppet valve. In brief, the simulation model
enables feed-forward control system for the EHVA system. Because of the simulation is used,
all specifications about the test rig equipment should be known to enter all necessarily
parameters for simulation model. Required equipment and their specifications are explained
below.
2.1- Modification of Test Rig
EHVA test rig was already existing but it was modified according to needs for new experiments.
First of all, test rig was designed to be more rigid. EHVA assembly and oil filter bracket was designed
to be more robust. This bracket allows to change oil filter easily, if it is necessary. Protective clear
polycarbonate sheet and its frame was designed to protect the operator from any leakage or frangible
parts. All leakages were fixed and sink was designed to catch oil leakage of the hydraulic actuator
which is completely normal. This leakage keeps away dust particle from the actuator. Test rig was
designed to become all connections with solid pipes. However, although pipes are ordered, they did
not arrive at the expected time. Therefore, flexible pipes are used which were already available.
Detailed Solidworks drawings for new designed parts are given in the appendix A. Desired designed
test rig appearance is like that;
MSc Automotive Engineering Page 28 of 93 Adil Karakayis
Figure.19 Back view of the test rig design [24]
Figure.20 Front view of the test rig design [24]
MSc Automotive Engineering Page 29 of 93 Adil Karakayis
Figure.21 Front view of the test rig design [24]
2.2- Test Rig Equipment
These equipment which are listed below are all required for actuation of a poppet valve and data
logging system. All necessarily specifications are given for the simulation model.
Figure.22 Equipment of test rig control system
MSc Automotive Engineering Page 30 of 93 Adil Karakayis
Figure.23 Back view of test rig equipment
Figure.24 Top view of test rig equipment
MSc Automotive Engineering Page 31 of 93 Adil Karakayis
Item Description Quantity
1 Oil tank x1
2 Hydra micro pack hydraulic pump x1
3 Electrical motor x1
4 Parker Olaer accumulator x1
5 Fox pressure switch x1
6 Parker high pressure oil filter x1
7 Moog servovalve x1
8 Kistler pressure transducer x1
9 Pressure transducer flange x1
10 Helipebs hydraulic valve actuator x1
11 Poppet valve x1
12 Control box x1
13 Main electrical box x1
14 Fuse box x1
15 TTi TG1010A function generator x1
16 Custom signal amplifier x1
17 Linear variable differential transformer x1
18 Microstrain signal conditioner x1
19 Kistler pressure charge amplifier x2
20 Tektronix TDS 220 oscilloscope x1
21 National instrument picoscope x1
22 Computer x1
23 Protective clear polycarbonate and frame x1
24 Oil filter & EHVA assembly bracket x1
25 High pressure flexible hydraulic pipes x1
26 Ball valve x1
27 Pressure gauge x1
Table.1 List of test rig equipment
2.2.1- Oil Tank
4.5 litre aluminium oil tank is used such as a secondary tank. When oil decreases in actual oil
reservoir of the hydraulic pump because of the leakage at hydraulic actuator, ball valve is opened to
fill it.
2.2.2- Hydraulic Pump and Electrical Motor
Hydraulic oil pressure source of the test rig is Hydra Products micro pack hydraulic pump. This
micro pack includes XV-0P/0.25 group fixed displacement gear pump. Mounting of the hydraulic
pump assembly should be horizontal because gear pump type is in tank and the filler position is at
the side of the pimp. Moreover, air breather position is at top. Additionally, it has pressure relief
MSc Automotive Engineering Page 32 of 93 Adil Karakayis
valve. When this valve is activated, it relieves all pressure in the system. Assembly includes 0.5 litre
plastic oil tank which can be filled by secondary oil tank. After it is filled ball valve should be closed.
Otherwise, all oil in the secondary tank comes out from the air breather. This pump which has
0.24𝑐𝑚3/𝑟𝑒𝑣 size has the capable of 260bar maximum pressure in the speed range of 700 to
9000rpm. According to the selection of the electric motor which is AC motor – 250 Watt 240V 50Hz
S2 duty in this project, moto-pump performance is given in the graph.17 in appendix A. The pressure
range is in between 10 to maximum 120 bar. Volumetric efficiency is in the range of 0.91 to 0.96,
mechanical efficiency is 0.85 to 0.90, recommended oil is mineral oil and working temperature range
is in between -15 to 70 𝐶° [16] [17].
2.2.3- Accumulator
Parker Olaer diaphragm accumulator which has the capacity of 0.16litre is used on the test rig to
stabilize the oil pressure in the system. It is pre-charged with nitrogen which gives maximum 130bar
pressure load [18].
2.2.4- Oil Filter
Any tiny dust particles can block servovalve or may affect the performance. Therefore, Parker
hydraulic filter is used on the test rig to filter out these particles. Although the size of the filter
elements are 10µm, pressure is not affected a lot. Pressure differential is 0.2 bar at 17.05 l/min flow
rate which is maximum flow rate of the servovalve. Therefore, it is not considered into the simulation
model. It can be seen in the graph.18 in appendix A. [20]
2.2.5- Pressure Switch
Fox F4 adjustable pressure switch is used on the test rig to control pressure in the system. Switch is
set to remain the system at determined pressure. It can be adjusted by rotating the screw with 2 mm
hexagonal key manually. This pressure switch is used for closed loop on/off control system. Working
principle is that when the oil pressure force is more than spring force which is adjusted by the screw,
needle opens the electric circuit. For this reason, main electric box cannot send any electric signal to
MSc Automotive Engineering Page 33 of 93 Adil Karakayis
the electric motor until pressure drop. While pressure drops, pressure switch closes electric circuit
and send electric signal back to the electric motor to increase the oil pressure [19].
Figure.25 Diagram of Pressure switch [19]
2.2.6- Moog Servovalve
Servovalve controls the flow rate for the hydraulic actuator according to electrical current signal. It
can be divided to three main parts which are torque motor, hydraulic amplifier and valve spool.
Operation procedure is such that electrical current signal creates magnetic forces on the armature
which creates torque according to the current value in the range of +/- 50 mA. This torque rotates the
flapper to close or reduce the opening area of the one end of the nozzle while opens or increases the
opening area of the other end. It changes the flow balance in the hydraulic amplifier. Changed flow
goes to return line through drain orifice which creates imbalance hydraulic force on the spool.
Because of that, the spool moves to one direction. When the spool moves one direction, it opens
pressure port on that direction which allows main oil flow to the hydraulic actuator. On the other
hand, it opens return port for the other end of the hydraulic actuator at the same time. Additionally,
MSc Automotive Engineering Page 34 of 93 Adil Karakayis
spool movement generates some force on the feedback spring which helps torque armature and
flapper to return its original position immediately after current signal becomes 0 value [23]. Moog
series 31 servovalve specifications are given in the table.2 Flow datasheet characteristics are given
in the graph.19 in appendix A.
Figure.26 Diagram of the servovalve [23]
System Pressure 280 bar (4000 Psi)
Rated Flow 15.0 l/min +/- 10% at 70 bar
Maximum Leakage 1.95 l/min
Rated Signal +/- 50.0 mA
Response Type High
Fluid Mineral oil
Seals N90D
Body Type 31 Series
Connector Type Bendix
Screws Std
Additional Comments 10% P-C2
Table.2 Moog servovalve specifications [22]
2.2.7- Hydraulic Valve Actuator Assembly
Helipebs hydraulic valve actuator is the main part of the test rig which provides movement of the
poppet valve according to the controlled oil flow. Working principle is very basic which oil fills the
MSc Automotive Engineering Page 35 of 93 Adil Karakayis
piston area in order to provide linear movement of the poppet valve. Poppet valve is attached on the
one end of actuator rod. Other end is used for LVDT sensor. There is no piston ring for sealing but
piston has four groves which are for lubrication of the piston to reduce the friction of the rod.
However, it creates small damping force. Therefore, viscous damping coefficient should be
calculated for the simulation by these equations;
𝑘δ =𝑑
δ …10
𝑘l = 𝑙
𝑑 …11
𝑏 = 𝜋 . 𝜌 . 𝑣 . 𝑘δ . 𝑘l . 𝑑 …12
Figure.27 Sectional view of the actuator rod piston and cylinder [35]
According to the equations, damping coefficient is equal to 1.6N.s/m.
Where;
𝜌: 843.64𝑘𝑔/𝑚3at 27𝐶°
𝑣: 125.427cst (0.000125427𝑚2/𝑠) at 27𝐶°
𝑑: 11.00mm
δ: 0.50mm
𝑙: 22.00mm
MSc Automotive Engineering Page 36 of 93 Adil Karakayis
Because of there is no sealing on the piston and heads, leakage occurs. In order to prevent leakage at
ports of servovalve and flange, O-rings are used in between pressure transducer flange and
servovalve. Ports should be exactly matched to avoid any dislocation of ports, when parts are
assembled. Therefore, dowels are used for each parts. Exploded view of the hydraulic actuator
assembly is illustrated in the figure.28
Figure.28 Exploded view of hydraulic valve assembly [24]
# Description
1 LVDT sensor
2 Top head of actuator
3 Pressure inlet for actuator
4 Return
5 Pressure line for servovalve
6 Return line
7 Kistler pressure transducers
8 Bolt for transducer
9 Pressure transducer flange
10 Moog type31 servovalve
11 Hydraulic actuator rod
12 Bottom head
13 Poppet valve
Table.3 Hydraulic valve assembly parts
Hydraulic actuator has complex geometry at two ends which improves end damping of actuator rod.
It is showed in the figure.29.
MSc Automotive Engineering Page 37 of 93 Adil Karakayis
Figure.29 Sectional view of hydraulic valve assembly [24]
Heads have some tolerance in between the cylinder. Head diameter is 10.62 mm and cylinder
diameter is 11.0 mm. In theory, oil passes through this tolerance to reach cavity for improving end
damping. Moreover, heads have groove to allow oil flow when the rod is at very end. For end
damping, 𝑉1 and 𝑉2 should be considered into the SimHydraulics double-acting hydraulic cylinder
block so they were calculated by using Solidworks drawings. 𝑉1 is 20.25𝑚𝑚3and 𝑉2 is 434.405𝑚𝑚3
2.2.8- Pressure Transducer Flange
Pressure transducer flange is assembled in between servovalve and actuator for measuring the
pressure differential of two pressure lines. This location is selected for pressure transducers because
of technical issues such as hardness of actuator body material. Although it is possible to drill with
carbide drill bit, it is too hard for tapping. Therefore, flange is made which is the easiest way to attach
pressure transducers on the pressure lines. By this method, dynamic of the fluid is affected as little
as possible.
MSc Automotive Engineering Page 38 of 93 Adil Karakayis
Figure.30 Hydraulic valve actuator and pressure transducer flange body [24]
# Description
1 Top pressure line
2 Bottom pressure line
3 Kistler bottom pressure transducer
4 Pressure transducer bolt
5 Pressure inlet for actuator
6 Pressure line for servovalve
7 Top pressure line
8 Bottom pressure line
Table.4 Pressure lines and measurement equipment
2.2.9- Poppet Valve
Conventional poppet valve is used for this project which has 36 mm diameter and 45 mm length.
2.2.10- Control Box
Control box has three functions which are data logging, communication to main electrical box and
signal triggering. Control box has high quality 0.1 microfarad capacitor for triggering cable ground
connection to avoid triggering the function generator without trigger signal because of electric motor
high current jump. Additionally, it has emergency button if anything goes wrong which activates the
pressure relief valve of hydraulic pump to relieve pressure in the system. Schematic drawing of the
control box is given in the figure.52 in appendix. A.
MSc Automotive Engineering Page 39 of 93 Adil Karakayis
2.2.11- Main Electrical Box
Main electrical box controls hydraulic pump according to signal of control box. Feedback control
system with on/off controller is used to control oil pressure into the system. Pressure switch is used
as an on/off switch. The main electrical box schematic drawing is given in figure.53 in appendix. A.
Figure.31 Block diagram of pressure control system
2.3- Oil Properties
Mobil Super 2000 10W 40 fully synthetic engine oil is used in this project because IC engines already
use this oil. Although this system can work with hydraulic oil which will give better performance. It
is important to know the performance of the EHVA system with standard engine oil to reduce the
cost of complete system on IC engines. Less components mean low cost. Typical properties of 10W
40 Mobil Super 2000 oil is given in the table.5
SAE Grade 10W 40
Viscosity ASTM D44S
CSt at 40 𝑪° 70
CSt at 100 𝑪° 10.8
Sulfated Ash, ASTM D874 (wt%) 0.96
Pour Point, ASTM D97 (𝑪°) -30
Flash Point, ASTM D92 (𝑪°) 226
Density at 15.6 𝑪°, ASTM D4052 (g/ml) 0.87
Table.5 Mobil Super 2000 4T oil properties [28]
2.4- Signal Generation System
Although the signal is calculated by the MATLAB/Simulink model, computer requires an interface
to generate analog signal for the servovalve. Firstly, Arduino Mega 2560 electronic board is used to
generate that signal. Even though it generates the signal successfully, modulation frequency which
MSc Automotive Engineering Page 40 of 93 Adil Karakayis
is 488 Hz is not enough to generate same signal form in valve opening time interval above 500 rpm.
Therefore, TTi TG1010A function generator is used which has higher frequency.
2.4.1- Arduino Mega 2560
As it is explained, MATLAB/Simulink model is used in this project to generate feed-forward signal
so interface should be able to communicate with MATLAB software. Arduino has able to do this
communication but it can generate just digital or PWM signal output. However, analog output is
required for signal amplifier to convert it current signal. Therefore, PWM signal is converted to the
analog signal by using low-pass filter which increases clock timing. Specifications of Arduino Mega
2560 is given in the table.6 [29].
Operation Voltage 5V
Input Voltage 7-12V
Input Voltage Limits 6-20V
Digital I/O Pins 54 (14 of them PWM)
Analog Input Pins 16
DC Current per I/O Pin 40mA
DC Current for 3.3V Pin 50mA
SRAM 8KB
EEPROM 4KB
Flash Memory 256KB (8KB used for Bootloader)
Clock Speed 16MHz
Table.6 Mobil Super 2000 4T oil properties [29]
PWM signal can be explained such as a duty cycle in the figure.32. The Arduino can generate 0-5v
which is equal to 0-255 in PWM. Therefore, Arduino generates 0 voltage when the signal is 0 and
constant 5 volt when the signal value is 255. However, any value in between these two values creates
duty cycle percentages in the PWM signal form. Therefore, by using low-pass filter, average of this
duty cycle can be converted to analog voltage output. Low-pass filter schematic drawing is given in
the figure.33. By changing the resistor or capacitor value response time which means frequency of
each period for the PWM signal can be changed. Response time is equal to multiplication of resistor
and capacitor value. Firstly, 10kohm resistor is tried. After that 4.7kohm and then 1kohm resistors
with 1microfarad capacitor. Which gives us respectively 0.01s, 0.0047s and 0.0001s for the period
time interval [30]. Additionally, sample rate of simulated signal into the MATLAB/Simulink model
MSc Automotive Engineering Page 41 of 93 Adil Karakayis
should be above this period time interval to be able to download it into the Arduino. These signals
which are just example are given in the graph.1
Figure.32 Pulse Width Modulation [30]
Figure.33 Schematic drawing of the low-pass filter [30]
First of all, signal into the MATLAB/Simulink model should have offset value because PWM cannot
generate negative values. Therefore, signal which is calculated into the model should be multiplied
by 127.5 and summed with 127.5 offset value to generate the signal in the range of 0-255. The plan
was generating the signal in the range of 0-5v. When the signal became below the offset value which
is 2.75v, negative value would be generated by custom designed signal amplifier. In other case, signal
would be positive.
MSc Automotive Engineering Page 42 of 93 Adil Karakayis
Figure.34 PWM form of MATLAB/Simulink servovalve signal [31]
Because of the limited memory of Arduino (256 KB) all model cannot be downloaded into the
Arduino so signal is saved to workspace of MATLAB for exporting it excel file. After that, it is
imported to signal builder into another model which is created for Arduino to download it into the
Arduino.
Figure.35 PWM conversion of MATLAB/Simulink servovalve signal for Arduino [31]
Graph.1 Comparison of response times a:1, b:4.7 and c:10kohm [32]
MSc Automotive Engineering Page 43 of 93 Adil Karakayis
Although, the signal form could be catch with 1kohm resistor and 1 microfarad capacitor low-pass
filter, it cannot be used to be connected to signal amplifier because there is too much noise. As a
solution of this problem function generator is used.
2.4.2- Function Generator
TTi TG1010A function generator is used to generate analog voltage for the simulated signal.
Simulated signal is saved in comma separated value form to be able to download it into the function
generator. RS-232 to USB adaptor is required for the connection of the function generator and
computer. Schematic drawing is given in the figure.36. Although the function generator can generate
downloaded signal form with high resolution (1023x1023), every time, frequency of function
generator should be adjusted very carefully to get same time interval of the signal with simulated
signal into the model. Signal can be controlled by an oscilloscope while frequency is adjusted.
Because of that, problem occurs. It is not easy to generate exactly same signal with the model. Thus,
some error occurs for the duration of valve opening.
Figure.36 Diagram of the RS-232 to USB adaptor [33]
MSc Automotive Engineering Page 44 of 93 Adil Karakayis
Repetition for signal form can be set to repeat signal as much as wanted. However, according to the
setup of test rig, triggering signal which comes from picoscope is required to activate triggering mode
of the function generator to do desired repetition. That triggering signal controls beginning of data
saving for picoscope also. Therefore, signal for servovalve and data saving is triggered at the same
time.
2.4.3- Signal Amplifier
Generated signal by the function generator is sent to signal amplifier to convert the voltage signal to
current signal form for the servovalve. There is a scale factor for current monitoring because signal
amplifier has10k ohm resistance in between the current monitoring and actual current signal which
goes to servovalve. Moreover, 1V is equal to 1A for current monitoring of signal amplifier for saved
data. Therefore, when measurements are illustrated in voltage such as 500 mV means 50 mA for
current monitoring in data analysis section. Schematic drawings of the custom designed signal
amplifier is given in the appendix. A.
2.5- Data Logging System
National instruments NI USB-6008 picoscope is used to save data in numerical form and Tektronix
TDS220 oscilloscope is used to illustrate real-time data for data logging of the test rig. Pressure
transducer’s signals are saved by the picoscope to determine the pressure differential of both inlet of
hydraulic actuator. For determining the displacement of the poppet valve, LVDT sensor signal is
saved. Finally, both function generator voltage and signal amplifier current signal monitoring are
saved by the picoscope to determine signal amplifier performance and signal which goes to
servovalve.
2.5.1- Pressure Transducers and Charge Amplifiers
Kistler piezoelectric sensors and charge amplifiers are used to measure pressure as it explained in
the section of 2.2.8. These pressure sensors are generally used to measure brake mean effective
pressure of IC engines but it works onto this system very well. Scale factor is 20 bar/v for both charge
amplifiers [34].
MSc Automotive Engineering Page 45 of 93 Adil Karakayis
2.5.2- Linear Variable Differential Transformer and Signal Conditioner
Graph.2 Calibration of the LVDT sensor
Microstrain LVDT sensor is used to measure the poppet valve displacement. LVDT sensor is
connected to the microstrain signal conditioner. Additionally, the signal conditioner is connected to
the picoscope to save the movement of the valve. This sensor is frictionless which means that it does
not affect the movement of the poppet valve. It is required to do calibration to know the values in
each mm movement. However, these values are reliable if the LVDT sensor does not remove or
replace. Slope is 2.972292 mm/V. Therefore, according to voltage output of the LVDT sensor,
displacement can be calculated by equation.13.
𝐷 = 𝑀 𝑥 𝑋 …13
2.5.3- Oscilloscope and Picoscope
Tektronix TDS220 oscilloscope is used to demonstrate real-time data for adjusting function generator
signal frequency. Additionally, LabVIEW Signal Express software is used to save data in numerical
form with picoscope. Configuration of the software is set to save data when it is triggered. Trigger
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
20.3 22.3 24.3 26.3 28.3 30.3
LVD
T Se
nso
re (
V)
Valve Displacement (mm)
LVDT Sensor Calibration
MSc Automotive Engineering Page 46 of 93 Adil Karakayis
source is on the picoscope channels where triggering switch is connected to PFIO to +5v channel
with an on/off switch. In the configuration, digital rising edge is selected to begin data saving.
Moreover, this triggering signal triggers the function generator also. All data is saved in voltage form
and scale factors are used to convert them in pressure, displacement and current form during
analysing. 5 analog channels are used on the 8 channel (10kHz) picoscope which are signal input
voltage after function generator, signal current monitoring after signal amplifier, two pressure
transducers and LVDT sensor output. Therefore, sampling rate for 5 channels becomes 2 kHz
(0.0005s). The voltage range of measurements is +/- 10v [26].
2.6- Test Rig Restrictions
Test rig has some restrictions because of high pressure oil so pressure endurances of each equipment
are given in the table.7.
Equipment Maximum Pressure (bar)
Parker oil Filter 414
Parker Olaer accumulator 210
Fox F4 Pressure switch 70
Hydra Products Hydraulic Pump 120
Moog servovalve 280
Flexible hydraulic hoses ≌220
Table.7 Test rig pressure restrictions [17] [18] [19] [20] [21]
MSc Automotive Engineering Page 47 of 93 Adil Karakayis
3- MATLAB/Simulink Simulation Model
Figure.37 MATLAB/Simulink model [31]
MSc Automotive Engineering Page 48 of 93 Adil Karakayis
Whole test rig is simulated by created MATLAB/Simulink model according to the real parameters
of the hydraulic components. Some realistic assumptions were done which are explained below.
Physical modelling components of Simscape such as SimMechanics and SimHydaulics were used to
create the simulation model of EHVA system. SimMechanics and SimHydraulics uses physical
connections so actual EHVA system matches with the simulation model as much as possible.
Subsystems for SimHydraulics and SimMechanics were used to make the model more tidy [36] [37].
Figure.38 Simulation model [45]
3.1- SimMechanics
SimMechanics are used to simulate physical properties of the poppet valve and hydraulic actuator
such as mass of the poppet valve and actuator rod. In addition to mass, viscous damping coefficient
of hydraulic piston which is calculated in the hydraulic valve actuator section is considered in the
model also. It can be entered by using the function of internal mechanics. Blocks are representing
bodies, joints, constraints and force elements. For example, Hydraulic_Valve_Assembly_1_RIGID
represents the constraints. Poppet_valve_with_hydraulic_rod_1_RIGID represents the moving part
in linear motion and cylindrical block represents cylindrical joint [38]. Figure.39 illustrates the
SimMechanics components of hydraulic actuator.
MSc Automotive Engineering Page 49 of 93 Adil Karakayis
Figure.39 SimMechanics simulation model [31]
Cylindrical joint is the most important part in the SimMechanics because it determines displacement,
velocity and acceleration of the poppet valve. In addition to them, physical connection of the poppet
valve actuation is provided by this block. As it can be seen in the figure.39 ideal force sensor is
connected to that physical line to calculate the force which acts on the poppet valve by hydraulic
cylinder. Moreover, ideal transitional velocity source is used to do the connection in between
SimMechanics and SimHydraulics. The reason of using this sensor is that sensing the movement of
the double acting hydraulic cylinder and converting it to force. After that, this force is applied to the
cylindrical joint to calculate the poppet valve velocity according to its weight and internal mechanics.
Finally, determined velocity is connected to the ideal transitional velocity source again for relative
velocity [41]. These sensors do not affect the connected physical line such as inertia, friction, delays
and energy consumption so they are called ideal sensors [39]. PS-Simulink Converters are used to
convert Simulink input signal to physical signal. Units of the output can be changed by using these
blocks [40]. These blocks were attached to scopes for illustrating solutions. The easiest way to
implement hydraulic valve actuator, actuator rod and poppet valve into the SimMechanics which was
drawn into the Solidworks is SimMechanics Link into the Solidworks. There are two generations for
MSc Automotive Engineering Page 50 of 93 Adil Karakayis
SimMechanics but second generation SimMechanics is used into this modelling which has less
blocks and more functions [38]. Additionally, SimMechanics can illustrate the movement of these
parts in 3D environment.
Figure.40 SimMechanics [31] [38]
3.2- SimHydraulics
SimHydraulics are used to simulate electric motor, hydraulic pump, accumulator, servovalve and
hydraulic actuator. Ideal angular velocity source, fixed-displacement hydraulic pump, gas-charged
accumulator, 4-way directional valve and double acting hydraulic cylinder components of
SimHydraulics are used to represent them respectively. PS-Simulink Converters are used for same
purpose. Hydraulic flow rate sensors were connected in between the DAHC and 4WDV to calculate
the flow rate according to opening signal of 4WDV [43] [46].
MSc Automotive Engineering Page 51 of 93 Adil Karakayis
Figure.41 SimHydraulics simulation model flow control [31]
Figure.42 SimHydraulics simulation model of power unit [31]
In the actual test rig, pump is rotated by the electric motor but in the simulation, pump is controlled
by an ideal angular velocity source. Therefore, pressure can be easily controlled by increasing or
decreasing the angular velocity of the pump [42]. There is a difference between actual test rig and
simulation model in this situation but it does not affect the signal which is simulated for the
MSc Automotive Engineering Page 52 of 93 Adil Karakayis
servovalve. The difference is that pump is not rotated continuously in the actual test rig because it
has control system to stop electric motor when it reaches the expected pressure. However, pump
rotates incessantly in the simulation to keep the pressure constant. Finally, hydraulic pressure sensor
is used to calculate the pressure in the simulation.
3.2.1- Hydraulic Fluid
Hydraulic fluid block was used to set oil properties which are explained in the chapter.2. Because
10W 40 oil is used hydraulic fluid was selected 10W in the block parameters. Relative amount of
trapped air was entered 0.0001 which is an assumption. System temperature was selected 27𝐶° which
is the room temperature because there is no heat source to heat the oil except pressurized oil itself
and electric motor. Therefore, experiments were repeated while the electric motor and oil cool down
to room temperature. Viscosity derating factor was entered 0.7028. As a result of these values,
hydraulic fluid block calculated the density, viscosity and bult modulus respectively 843.64𝑘𝑔/𝑚3,
125.427cst and 1.83784𝑒9. These calculations are matched with real parameters.
3.2.2- Hydraulic Pump
All hydraulic pump parameters which are explained in the chapter.2 are required for the fixed-
displacement hydraulic pump block. Pump displacement was entered 24𝑒−7𝑚3/𝑟𝑒𝑣. Volumetric
and mechanical efficiencies were entered 0.92 and 0.87. Finally, nominal pressure, angular velocity
and kinematic viscosity were entered respectively 120bar, 314rad/s and 0.001567𝑚2/𝑠.
3.2.3- Accumulator
Accumulator parameters are such that capacity is 0.16litre, pre-load pressure is 130bar, initial volume
0𝑚3, specific heat ratio is 1.4 and structural compliance is 1𝑒−13𝑚3/𝑃𝑎. Last two parameters are
assumptions.
3.2.4- 4-Way Directional Valve
This component simulates the most important part of whole system which is Moog servovalve.
Normally, the servovalve system is more complex than a 4WDV but all required parameters have
not been known so it is simplified by using 4WDV. Although it is simplified, it does its job as good
MSc Automotive Engineering Page 53 of 93 Adil Karakayis
as possible. The principle of 4WDV is that the signal is connected to the signal port which controls
the spool movement. Movement of the spool is scaled in the range of 0-100% for one direction which
means for fully opening, it will be 100% and for fully closing, it will be 0%. Spool can move both
direction so the range becomes -100 to 100%. According to rated input signal, spool opens port A or
B as determined area [47]. Opening areas are given in the table.8
Figure.43 4-way directional valve block [44]
The spool opening areas which is given in the table.8 are calculated by optimization tool for 4-way
directional valve according to Moog series 31 servovalve flow datasheet characteristics. Flow data
sheet is given in the appendix A. In the MATLAB/Simulink model, 4WDV has 100% efficiency for
spool movement so it can open instantaneously. However, actual servovalve cannot do this because
it has torque motor delay, hydraulic amplifier delay and spool inertia. Therefore, if rapid opening is
required which is showed in the figure.44, transfer function should be applied into the model just
before 4WDV signal to simulate phase lag. Generally, it is required for exact square valve profile.
For other cases, simulation model is good enough. Signal change can be seen in the figure.44 by
using transfer function.
MSc Automotive Engineering Page 54 of 93 Adil Karakayis
Figure.44 Moog servovalve transfer function effect [31]
Moog servovalve transfer function is given by the manufacturer such that;
Figure.45 Moog servovalve transfer function [49]
MSc Automotive Engineering Page 55 of 93 Adil Karakayis
During the calculation of Moog series 31 servovalve phase lag, sine wave was used so frequency is
from peak to peak [49]. Therefore, period interval should be calculated in between opening and
closing signals. First order transfer function is good enough up to 1500rpm. Above that engine speed,
second order transfer function should be used up to 300Hz. However, transfer function was not use
in the simulation model because of the factors which are explained with more details in the optimized
valve lift profile section. For valve lifting profile, there is not any square shape.
3.2.5- Optimization Tool for 4-Way Directional Valve
This optimization tool is created by Mathwork engineers to tune the 4WDV opening areas according
to Moog series 31 servovalve flow datasheet characteristics by using optimization algorithms.
Figure.46 Optimization Tool for 4-Way Directional Valve [48]
This MATLAB optimization tool uses these equations with iteration system to calculate valve
opening areas for required flow rate.
𝑞 = 𝐶𝑑 . 𝐴√2 |𝑃|
𝑃𝑠𝑖𝑔𝑛(𝑃) …14
𝐴 =𝐴𝑚𝑎𝑥
ℎ𝑚𝑎𝑥 ℎ …15
ℎ𝑃𝐴 = ℎ𝑃𝐴,0 + 𝑥 …16
MSc Automotive Engineering Page 56 of 93 Adil Karakayis
ℎ𝑃𝐵 = ℎ𝑃𝐵,0 + 𝑥 …17
ℎ𝐴𝑇 = ℎ𝐴𝑇,0 + 𝑥 …18
ℎ𝐵𝑇 = ℎ𝐵𝑇,0 + 𝑥 …19
There is an assumption which is ℎ𝑃𝐴 = ℎ𝑃𝐵 = ℎ𝐴𝑇 = ℎ𝐵𝑇 = 0 because it is not known if the
servovalve spool has initial opening. There are another assumptions which are 1x10−9𝑚𝑚2 leakage
area and 0.2𝑚𝑚2 maximum spool opening area for the optimization tool. By entering flow rate
parameters of Moog servovalve and pressure drop in bar, opening areas can be calculated. In table.8
flow rates are given according to rated movement of the spool.
Breakpoints Actual Servovalve
current (mA)
Vector Output
Values (mm)
Flow Rate
(lpm)
Opening Areas
(𝒎𝒎𝟐)
0 0 0 0 0
1 5 0.1 2.25 0.000795
2 10 0.2 3.79 0.001327
3 15 0.3 5.68 0.001987
4 20 0.4 7.57 0.002647
5 25 0.5 9.46 0.003308
6 30 0.6 11.36 0.003972
7 35 0.7 13.25 0.004632
8 40 0.8 14.57 0.005093
9 45 0.9 15.9 0.005558
10 50 1 17.03 0.005942
Table.8 Flow datasheet characteristics of series 31 Moog servovalve [23]
3.2.6- Double-Acting Hydraulic Cylinder
Double-acting hydraulic cylinder component is used for simulating the hydraulic actuator. As it
mentioned in chapter.2 and as it can be seen in the figure.27, viscous damping coefficient parameters
were entered via SimMechanics cylindrical joint internal mechanics so the model does not have
additional dumping component. The block parameters are given in table.9.
Piston Area A (𝒎𝟐) 0.0000114
Piston Area B (𝒎𝟐) 0.0000114
Piston Stroke (m) 0.0118
Dead Volume A (𝒎𝟑) 0.000000454655
Dead Volume B (𝒎𝟑) 0.000000454655
Specific Heat ratio 1.4
Contact Stiffness (N/m) 100
Contact Damping (N.s/m) 1.5
MSc Automotive Engineering Page 57 of 93 Adil Karakayis
Chamber A Initial Pressure (bar) 70
Chamber B Initial Pressure (bar) 70
Table.9 Double-acting hydraulic cylinder block parameters
3.3- Control System
Feed-forward control system is used for the test rig which has some benefits such as LVDT sensor
does not required which means less cost. For this project, LVDT sensor was assembled to illustrate
actual movement of the poppet valve. Although feed-forward control systems is used for actual
servovalve signal (figure.18), feedback control system is used to simulate the signal in the simulation
model for the feed-forward control system. As it explained in chapter.2, simulation is used to
simulate the movement of the poppet valve according to desired profile. Accordingly, required flow
rate is calculated for the movement to open valve (spool) of 4WDV. In summary, Feedback control
system is used to calculate the signal for opening of the spool according to required flow rate. After
that, simulated signal is used such as feed-forward signal for actual servovalve.
Figure.47 Block diagram of the simulation feedback control system
Figure.48 Block diagram of feed-forward control system of the test rig
MSc Automotive Engineering Page 58 of 93 Adil Karakayis
Error occurs in between desired position and actual position of the poppet valve in the simulation.
Therefore, all parameters were entered as real as possible to simulate the actual EHVA system error
for generating realistic feed-forward signal. PID controller is used to fix that error. Even though just
proportional part was used for experiments, integral and derivative parts also can be used to improve
correction of the error. Working principle is such that desired profile is sent to 4WDV by using signal
builder, this signal is subtracted from actual position of the poppet valve which is 0 at the beginning.
Therefore, error becomes highest value at that point which is multiplied by determined proportional
value. This value becomes 4WDV opening signal. According to that signal, it sends calculated
amount of oil flow to DAHC. Poppet valve moves up to the amount of DAHC movement and this
position is sent back to be subtracted from desired profile signal. While error reduces, opening signal
of the 4WDV changes. This signal is saved to download into the function generator to become feed-
forward signal for the desired profile. However, signal should be inverted while it is downloaded
into the function generator because of the signal amplifier terminal connections.
4- Method of Experiments
Experiments were done for 800, 1000, 1500, 2000, 2500, 3000, 4000, 5000 and 6000rpm engine
speeds for both valve lift profiles. First of all, V-tec camshaft profile which is for B15C2 Honda
engine was tried to be followed. After that, this profile was improved for that specific engine by
using the flexibility of EHVA system. These profiles were imported into the simulation model by
using signal builder block of MATLAB/Simulink. Afterwards, 4WDV input signals which are saved
by Simout block were downloaded into the function generator after they were inverted. Frequencies
of these signals were adjusted to have same time interval with the simulated signals. Offset values
were adjusted to close the valve fully and balance the hydraulic amplifier of the servovalve.
Downloaded signals were sent to the signal amplifier by triggering to allow the signal amplifier
changes them from voltage to current form. Subsequently, current signal was sent to the Moog
servovalve in order to provide movement of the actual poppet valve. The movement was saved by
picoscope via LVDT sensor. During these processes, pressure on both inlets of hydraulic actuator
were saved by picoscope via pressure transducers to analyse dynamics of hydraulic actuator
MSc Automotive Engineering Page 59 of 93 Adil Karakayis
behaviour. All these processes are explained with more details in chapter.2. Operation procedure is
given in the table.10
# Description
1 Run simulation in MATLAB/Simulink model
2 Save signal data in Sigdata.csv file format
3 Download it into TTi TG1010A function generator
4 Check all sensors and actuator connections
5 Check all pipe connections
6 Turn on main switch on main electrical switch
7 Press “on” button to run hydraulic pump which is on control box
8 Adjust pressure switch to 70bar
9 Adjust offset value for servovalve
10 Run picoscope software
11 Press “triggering” button which is on control box
12 Collect data and save them
13 Press “off” button to stop hydraulic pump which is on control box. It will release
all pressure in the system
14 Press “emergency” button to relief all pressure into the system if anything goes
wrong
Table.10 Operation procedure of the test rig
Experiment Engine Speed
(rpm)
Proportional
Gain
Frequency
(Hz)
DC Offset
(mV)
Amplitude (Vpp)
(Peak-Peak)
1 800 0.2 25 -100 0.85
2 1000 0.3 24 -100 0.9
3 1500 0.3 36 -100 1.3
4 2000 0.4 46 -90 1.8
5 2500 0.5 52 -80 1.95
6 3000 0.6 62.2 -50 2.4
7 4000 0.8 100 -40 3
8 5000 0.8 105 -30 3.05
9 6000 0.9 125 -20 3.8
Table.11 Function generator and Simulink model parameters for V-tec camshaft profile
Experiment Engine Speed
(rpm)
Proportional
Gain
Frequency
(Hz)
DC Offset
(mV)
Amplitude (Vpp)
(Peak-Peak)
1 800 0.3 20 -100 0.92
2 1000 0.3 27 -95 1.22
3 1500 0.5 37.5 -75 1.8
4 2000 0.7 55 -69 2.7
5 2500 0.8 56 -55 3
6 3000 0.9 68 -55 3.2
7 4000 1 68 -50 3.3
8 5000 1.1 70 -35 4.3
9 6000 1.2 84 -35 4.87
Table.12 Function generator and Simulink model parameters for optimized profile
MSc Automotive Engineering Page 60 of 93 Adil Karakayis
4.1- V-tec Camshaft Profile
V-tec full lift camshaft profile was used to be followed to prove that the EHVA system have ability
to produce existing profiles. Camshaft profile is given in the graph.3.
Graph.3 V-tec camshaft profile [51]
As it can be seen in the graph.3, camshaft profile is given in crankshaft angles but signal builder into
the simulation model cannot accept degrees so these equations are used to calculate time interval per
one crankshaft angle.
𝜃𝐶 . (1
𝑟𝑝𝑚/60) /360 …20
Opening durations of valve profiles for 210CA V-tec camshaft and desired valve lift according to
engine speeds are given in the table.13.
Engine Speed
(rpm)
V-tec Profile Opening
Duration (ms)
Optimized Profile Opening
Duration (ms)
800 43.75 37.5
1000 35.00 30.0
1500 23.33 20.0
2000 17.50 15.0
2500 14.00 12.0
3000 16.60 10.0
4000 8.750 7.50
5000 7.000 6.00
6000 5.830 5.00
Table.13 Opening duration of 210CA camshaft and 180CA desired profiles
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0
1
2
3
4
5
6
7
8
9
10
0 50 100 150 200 250 300
Val
ve V
elo
city
[m
m/d
egr
ee
]
Val
ve L
ift
[mm
]
Cam Angle [degrees]Exhaust Valve Lift Primary Valve LiftSecondary Valve Lift VTEC Valve LiftExhaust Valve Velocity Primary Valve Velocity
MSc Automotive Engineering Page 61 of 93 Adil Karakayis
4.2- Desired Valve Lift Profile
EHVA systems which eliminate dependency of the restrictive camshaft profile and give freedom for
each valves allow infinitely controls for valve lifting, duration and variable timing. Therefore, V-tec
camshaft profile was optimized with the flexibility of EHVA system. Although this system has ability
to provide almost square valve profile. There are some limitations for IC engine volumetric efficiency
in addition to mechanical limitations such as valve failure under high speed opening and closing
conditions [14] [52] [53]. For this reason, during the optimization of valve opening profile for B15C2
engine volumetric efficiency and valve opening and closing velocities are considered too. B15C2
engine required parameters are given in the table.14 to calculate valve opening profile without air
choking condition. Moreover, valve full lifting should be at maximum piston speed. Accordingly,
volumetric efficiency was calculated as high as possible by considering piston speed and air choking
during the calculation of valve lifting profiles. Although it is required to do more complex
calculations and experiments to determine the best profile for an engine, equation.1, 2, 3, 4, 5, 6, 7
and 8 are used for calculation of valve lifting profiles for opening. Unlike opening profiles, just valve
speed was considered for closing profiles because opening duration time should be as much as
possible for letting air breathing more. However, it cannot have square profile because of the speed
factor so it is calculated to limit speed of the valve as little as possible without losing area. Finally,
the equation for 180CA opening profile becomes such that;
𝑠 = 𝑎. sin(𝜃𝐶) + (𝑙2 − 𝑎2𝑠𝑖𝑛2(𝜃𝐶))1/2 …21
𝑆𝑝 =𝑑𝑠
𝑑𝑡 …22
𝐿𝑣 = 𝐴𝑝.𝑆𝑝
(0.676.𝐶𝑖.𝜋.𝐶𝐷𝐷𝑣)𝑥1000 …23
Where;
𝐴𝑝: 0.010306𝑚2
𝑆𝑝: Changes with the engine speed
𝐶𝑖: 364.1346m/s
MSc Automotive Engineering Page 62 of 93 Adil Karakayis
𝐶𝐷: It is assumed 0.6
𝐷𝑣: 0.036m
Figure.49 IC engine geometry for piston speed calculation [54]
Bore “B”
(mm)
Connecting Rod Length “l”
(mm)
Crankshaft Radius “a”
(mm)
81 137.9 77.4
Table.14 Honda B15C2 engine specifications [55]
Although all profiles are given in the experiment result section, an opening profile is given in the
graph.4 to illustrate one of the desired profile shape. The difference in between opening profile and
closing profile can be seen in the graph.4. Moreover, while engine speed increases, opening profile
changes because of the relation of piston speed and valve lifting profile. After 2500rpm, due to speed
MSc Automotive Engineering Page 63 of 93 Adil Karakayis
factor, same opening profile with 2500rpm was used for above engine speeds. On the other hand,
closing profile is fixed for every engine speeds.
Graph.4 Desired valve profile for 1000rpm
5- Experiment Results and Analysis
18 experiments were done for each engine speed and both profiles. Therefore, it is not possible to
illustrate every experiment results in this report. Thus, major points are explained in this section.
Other experiment results and analysis are given in the attached CD at the back of the dissertation.
Although experiment’s target pressure is 70bar, all experiments were done in the pressure range of
68 to 72bar for both V-tec and optimized valve profiles. Because of the pressure switch low response,
control system is unable to maintain the constant pressure. Minimum error was caught at 800 and
1000rpm so every explanations of analysis will be at these engine speeds. Moreover, explanation of
reasons for increasing error of the other engine speeds are given in this section also. Additionally,
time interval in each 5 crank angle becomes approximately 0.0002 but picoscope can record with dt:
0.0005 (2kHz). Therefore, some points are missed in data logging after 2000rpm. For example, it can
-4
-3
-2
-1
0
1
2
0
2
4
6
8
10
12
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
Vel
oci
ty (
m/s
)
Lift
(m
m)
Time (s)
Desired Profile (1000rpm)
Desired Lift (mm) Desired Velocity (m/s)
MSc Automotive Engineering Page 64 of 93 Adil Karakayis
be seen clearly for optimized profile input signal at 5000 and 6000rpm. First of all, V-tec camshaft
profile comparison is given to illustrate the error of the actual valve lift according to varying engine
speed from 800 to 6000rpm. Although EHVA system has the capable of lifting profile repetitions,
each experiment is done separately because just one signal form can be downloaded into the function
generator. However, they are combined to show them together in a graph. Repetition experiments
analysis are given in the CD.
Graph.5 Comparison of desired, simulation and actual valve lift for V-tec lift profile
Duration of the signal is adjusted by adjusting function generator frequency. It is explained in
chapter.2 with more details. Therefore, one of the reason of these errors for valve opening durations
are because of human error in addition to simulation error. Errors are acceptable up to 2000rpm but
after that engine speed valve lifting begins to lose which is directly related about pressure. By
increasing the pressure, it can be solved but leakage of the actuator will also increase so without
doing experiment with higher pressure it is hard to predict that. Valve speed comparisons are given
in the graph.6.
0
2
4
6
8
10
12
0 0.05 0.1 0.15 0.2 0.25 0.3
Lift
(m
m)
-En
gin
e sp
eed
x1
00
0(r
pm
)
Time (s)
Valve Lift
Desired Lift (mm) Engine Speed x1000 (rpm) LVDT(mm) Simulation Lift (mm)
MSc Automotive Engineering Page 65 of 93 Adil Karakayis
Graph.6 Comparison of desired and actual valve speeds for V-tec lift profile
Even though speed of the valve is almost matched with desired speed up to 1000rpm after that engine
speed, valve could not move fast enough to catch desired profile so speed of the actual valve
movement is less than desired valve speed. Signal of function generator and after signal amplifier
which is called current monitoring is given in the graph.7.
Graph.7 Input signals for V-tec lift profile (500mV=50mA)
-20
-15
-10
-5
0
5
10
15
0
1
2
3
4
5
6
7
0 0.05 0.1 0.15 0.2 0.25 0.3
Vel
oci
ty (
m/s
)
Engi
ne
Spee
d (
x10
00
rpm
)
Time (s)
Valve Speed
Engine Speed x1000 (rpm) Desired Velocity (m/s) Actual Velocity (m/s)
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
0
1
2
3
4
5
6
7
0 0.05 0.1 0.15 0.2 0.25 0.3
Am
plit
ud
e (V
)
Engi
ne
Spee
d (
x10
00
rpm
)
Time (s)
Input Signal
Engine Speed x1000 (rpm) Current Monitoring (A) Input Signal (v)
MSc Automotive Engineering Page 66 of 93 Adil Karakayis
As it can be seen in the signal analysing, oil flow rate is related by time and servovalve spool opening.
Therefore, the spool should be opened more to get same oil flow rate in shorter time interval to supply
more oil into the hydraulic cylinder. Furthermore, there is an offset value for the moog servovalve.
While amplitude increases offset value changes also in the function generator but output voltage is
almost same. DC offset value of the function generator is very important because servovalve spool
does not close ports at the beginning. In theory, it might happen because servovalve spool has initial
openings with ports or internal leakages of the spool. The other reason might be that the spool does
not stop, it always moves one direction excessive slowly while DC offset is given. Therefore, DC
offset should be adjusted very carefully to close ports. Otherwise, offset value may affect by ignoring
or reducing opening or closing signal. It depends which way is selected. As it explained above, it is
assumed to move very slowly to one direction. Therefore, in these experiments, DC offset value is
selected to close valve fully which means spool direction is selected to move one direction excessive
slowly to open one port to allow oil flow for pushing valve to be fully close. After that, signal is sent
to servovalve. Value of DC offset is selected very low to do not affect the signal and can be different
a little bit for function generator when same experiment is repeated. However, it is same for output
of function generator according to the graph.7. For example, DC offset value may change + and - 5
mV. Table of function generator parameters are given in chapter.4.
Graph.8 Comparison of the valve lifting for V-tec lift profile at 1000rpm
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0
2
4
6
8
10
12
0 0.005 0.01 0.015 0.02 0.025 0.03
Sign
al (
x0.1
A)
Lift
(m
m)
Time (s)
V-tec Camshaft Profile vs Signal (at 1000rpm)
LVDT(mm) Desired Lift (mm) LVDT(mm) Simulation (mm) Current Monitoring (A)
MSc Automotive Engineering Page 67 of 93 Adil Karakayis
Graph.9 Valve speed for V-tec lift profile at 1000rpm
Graph.10 Pressure of the hydraulic actuator inlets according to V-tec lift profile at 1000rpm
Although actual valve lifting error is low at 1000rpm which is the lowest error for V-tec profile,
valve closes too fast. It should be improved to avoid valve failure. Hydraulic actuator both sides
pressure are given in the graph.10. Dynamic behaviour can be understood from these pressure
measurements. They are used to improve simulation model by comparing them with the calculated
pressure into the simulation model. For instance, because of the Moog servovalve spool internal
geometry is not known, opening areas of the 4WDV were assumed according to optimized tool of
-4
-3
-2
-1
0
1
2
3
0
2
4
6
8
10
12
0 0.005 0.01 0.015 0.02 0.025 0.03
Vel
oci
ty (
m/s
)
Lift
(m
m)
Time (s)
Valve Speed (at 1000rpm)
LVDT(mm) Desired Lift (mm) Actual Velocity (m/s) Desired Velocity (m/s)
-20
-10
0
10
20
30
40
50
0
1
2
3
4
5
6
7
8
9
10
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04
Pre
ssu
re (
Bar
)
Lift
(m
m)
Time (s)
Pressure (at 1000rpm)
LVDT(mm) Bottom Pressure (bar) Top Pressure (bar)
MSc Automotive Engineering Page 68 of 93 Adil Karakayis
MATLAB. However, these areas are modified to get similar pressure graph into the simulation
model. Pressure measurements demonstrate pressure differential of both inlets. Pressure drop can be
seen for both inlets at valve opening and closing times. Pressure graphs are very similar because the
profile is same for valve opening and closing. However, they are not same for optimized profile
which is illustrated in the graph.16. Secondly, Optimized valve lifting profile comparison is given to
show actual valve lifting error for varying engine speed from 800 to 6000rpm. Lowest error is at
800rpm for optimized profile experiments. Although displacement of the hydraulic actuation is
11.8mm, desired poppet valve lift is maximum 10mm to prove that valve does not fluctuate at full
lift opening duration. Similar to camshaft profile experiments, valve lifting begins to lose after
1000rpm.
Graph.11 Comparison of desired, simulation and actual valve lift for optimized lift profile
Valve speed is given in the graph.12 which demonstrates error increases as engine speed increase
because valve lift profile does not follow desired lift profile as expected.
0
2
4
6
8
10
12
0 0.05 0.1 0.15 0.2 0.25 0.3
Lift
(m
m)
-En
gin
e Sp
eed
(x1
00
0rp
m)
Time (s)
Valve Lift
Desired Lift (mm) Simulation Lift (mm) LVDT(mm) Engine Speed x1000 (rpm)
MSc Automotive Engineering Page 69 of 93 Adil Karakayis
Graph.12 Comparison of desired and actual valve speeds for optimized lift profile
Graph.13 Input signals for optimized lift profile (500mV=50mA)
Valve opening and closing profiles have differences as it mentioned before. Therefore, signals for
opening and closing are different also as demonstrated in graph.13. When engine speed increases,
both profiles becomes similar so signal also becomes similar. However, after 2000rpm data logging
-22
-17
-12
-7
-2
3
8
13
18
23
0
1
2
3
4
5
6
7
0 0.05 0.1 0.15 0.2 0.25 0.3
Vel
oci
ty (
m/s
)
Engi
ne
Spee
d (
x10
0rp
m)
Time (s)
Valve Speed
Engine Speed x1000 (rpm) Desired Velocity (m/s) Actual Velocity (m/s)
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
0
1
2
3
4
5
6
7
0 0.05 0.1 0.15 0.2 0.25 0.3
Am
plit
ud
e (V
)
Engi
ne
Spee
d (
x10
00
rpm
)
Time (s)
Input Signal
Engine Speed x1000 (rpm) Current Monitoring (A) Input Signal (v)
MSc Automotive Engineering Page 70 of 93 Adil Karakayis
system sample rate does not enough to save each 5CA. It can be seen easily on 5000 and 6000rpm
input signals.
Graph.14 Comparison of the valve lifting for optimized lift profile at 800rpm
Graph.15 Valve speed for V-tec lift profile at 1000rpm
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0
1
2
3
4
5
6
7
8
9
10
0 0.01 0.02 0.03 0.04
Sign
al (
x0.1
A)
Lift
(m
m)
Time (s)
Optimized Profile vs Signal ( at 800rpm)
Simulation (mm) LVDT(mm) Desired Lift (mm) Current Monitoring (A)
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
0
1
2
3
4
5
6
7
8
9
10
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04
Vel
oci
ty (
m/s
)
Lift
(m
m)
Time (s)
Valve Speed (at 800rpm)
Desired Lift (mm) LVDT(mm) Desired Velocity (m/s) Actual Velocity (m/s)
MSc Automotive Engineering Page 71 of 93 Adil Karakayis
Graph.16 Pressure of the hydraulic actuator inlets according to optimized lift profile at 800rpm
Same problem with V-tec lift profile occurs in this profile also. Valve closes very quickly which
might cause valve failure. Pressure graph of the optimized valve lift profile is used to modify
MATLAB/Simulink model to adopt it actual test rig.
5.1- Discussion of Experiment Results
Although simulation model is used to create signal form of the desired valve lift profile, signal form
is distorted partially while it is downloaded into the function generator. Moreover, signal is changed
partly by signal amplifier also. Furthermore, it changes a little when the frequency is adjusted because
of human error. For these reasons, error becomes more than it should be. Thus, besides simulation
model, signal generation system is also required to improve. As it expected, valve lifting profile error
increased while engine speed increased. The pressure should be increased to fix that error because
flow rate does not enough to fill hydraulic actuator instantaneously in 2500rpm and above engine
speed's time intervals. If pressure switch is replaced, test rig pressure endurance changes which
means EHVA system pressure can be increased up to 120bar. This increment may reduce that error.
-40
-30
-20
-10
0
10
20
30
40
50
0
1
2
3
4
5
6
7
8
9
10
0 0.01 0.02 0.03 0.04 0.05
Pre
ssu
re (
Bar
)
Lift
(m
m)
Time (s)
Pressure (at 800rpm)
LVDT(mm) Bottom Pressure (bar) Top Pressure (bar)
MSc Automotive Engineering Page 72 of 93 Adil Karakayis
6- Future Work
This setup which was created to do experiments works quite well but transitions of signals for
different engine speeds takes time. Therefore, although this system can be applied for real engine, it
is not possible to do experiments for different engine speeds at once. Which means that if the setup
is configured for 1000rpm, engine speed should be exactly 1000rpm. It can be done by making a one
tooth trigger wheel which is connected to the cranks shaft. This system will enables to know piston
position to triggering the function generator for the signal and picoscope at the same time instead of
manually triggering. This experiment can be repeated for different engine speeds. However, there is
a solution for that problem which is XPC target or similar interfaces. By using XPC target, it is
possible to change the setup to do experiments with real-time controls. This is called hardware in the
loop system [56]. Additionally, this system enables to measure the pressure into the EHVA system
to change the parameters into the simulation model. Because of the simulation model is sensitive to
pressure changes, it will change the 4WDV control signal. Possible pressure sensing model is
demonstrated in the figure.50
Figure.50 SimHydraulics actual pressure measurement for power unit [31]
Moreover, it will enable to change the controller parameters in real-time. Besides all these
improvements, it is required to change the 100% 4WDV block by advanced servovalve model which
MSc Automotive Engineering Page 73 of 93 Adil Karakayis
is provided by MATLAB/Simulink [8]. This replacement will be improved the simulation model to
generate more realistic signal to become more compatible with the real test rig. However, it is
necessary to know all internal dimensions and specifications to enter them into the advanced
servovalve model. This model has simulations blocks of flapper/armature for torque motor,
flapper/nozzle for hydraulic amplifier and main valve for the spool.
Figure.51 SimHydraulics advance servovalve model [31]
Finally, in addition to these improvements feedback control system might be added to feed-forward
control system to reduce the error. It might work better than just feedback or feed-forward control
system because feed-forward will reduce the huge error for feed-back control system. Therefore,
possible collision of the poppet valve and piston wil be avoided.
MSc Automotive Engineering Page 74 of 93 Adil Karakayis
Conclusion
This project is about the investigation of control system strategies for hydraulic valve actuation in an
IC engine. This investigation makes possible to increase flexibility of control of valve lifting profile,
timing, and duration. Which might reduce significant amount of fuel consumption and exhaust
emission by using advanced engine strategies. In this project, feed-forward control system is used to
control EHVA system which is required pre-calculation to determine the signal form of servovalve
to manage hydraulic actuator. Therefore, MATLAB/Simulink Simscape physical modelling
components are used such as SimMechanics and SimHydaulics to simulate required signal form for
EHVA system. First of all, existing camshaft profile was followed to prove that the EHVA systems
have capable of existing technologies. Secondly, this profile is optimized to illustrate that this
systems can remove the restrictions of camshaft profiles and VVA systems. Although experiments
were done from 800 to 6000rpm, utilizable profile forms are just up to 2000. However, in my opinion,
this engine speed is good enough to do experiments of advance engine strategies on research engines.
Even though 18 experiments were done, it does not possible to insert each experiment analysis in
this report. Therefore, major points are explained in this report and other analysis of experiment are
insert into the CD which is attached at the back of the report. MATLAB/Simulink model files,
solidworks drawings, valve lift profiles, function generator signals, test rig equipment specifications
and interim report are inserted into the CD also.
MSc Automotive Engineering Page 75 of 93 Adil Karakayis
References
[1] Grey, J. A., 2013. Electronic-Valve-Actuation-in-Combustion-Engine-libre. BSc. University of
Queensland. Available at:
<http://www.academia.edu/4043972/Electronic_Valve_Actuation_in_Combustion_Engine>
[Accessed on 12 August 2014]
[2] Brader, S. J., 1995. Development of a Piezoelectric Controlled Hydraulic Actuator for a
Camless Engine. BSc. University of Boston. Available at:
<http://www.me.sc.edu/research/aarg/thesis%20final.pdf> [Accessed on 10 July 2014]
[3] Cam belt, 2014. The engine how the valves open and close. [Image online] Available at:
<http://www.howacarworks.com/basics/the-engine-how-the-valves-open-and-close> [Accessed on
12 August 2014]
[4] Cam lobe, 2014. Cam lobe design. [Image online] Available at:
<http://image.popularhotrodding.com/f/tech/solid-vs-roller-cams/18473101/cam-lobe-design.jpg>
[Accessed on 12 August 2014]
[5] Camshaft profile, 2014. Compcams overlap. [Image online] Available at: <http://www.moto-
east.com/main/wp-content/uploads/2013/12/compcams_overlap.gif> [Accessed on 12 August
2014]
[6] VarioCam, 2014. VarioCam cam phasing system. [Image online] Available at:
<http://www.taringa.net/posts/autos-motos/16177961/Distribucion-variable-1era-parte.html>
[Accessed on 13 August 2014]
[7] Cam-changing and Cam-phasing, 2014. Variable Valve Timing. [Image online] Available at:
<http://www.autozine.org/technical_school/engine/vvt_31.htm> [Accessed on 13 August 2014]
[8] MathWorks, Inc. 2014. Hydraulic System with Servo-Valve. [Online] Available at: <
http://www.mathworks.co.uk/help/physmod/hydro/examples/hydraulic-system-with-servo-
valve.html > [Accessed on 07 June 2014]
[9] Cam phasing system, 2012. Intelligent -Variable Valve Timing and Lift Electronic Control.
[Image online] Available at: <http://icrixs.wordpress.com/pend-otomotif/mesinengine/mekanisme-
katup/i-vtec/> [Accessed on 13 August 2014]
[10] Audi valvelift, 2008. Audi Variable Valvelift System in Detail [Image online] Available at:
<http://www.worldcarfans.com/1080626859/audi-variable-valvelift-system-in-detail> [Accessed
on 13 August 2014]
[11] McCharty, J. and Stretch, D. 2012. Compact, electro-hydraulic, variable valve actuation
system providing variable lift, timing and duration to enable high efficiency engine combustion
control. In: US Department of Energy, High-Efficiency Engine Technologies. Dearborn, 18 October
2012. US: Eaton Corporation.
MSc Automotive Engineering Page 76 of 93 Adil Karakayis
[12] Hall, G., n.d. Ricardo Advanced Research Engines – Single cylinders. [Online pdf] Shoreham-
by-Sea: Ricardo UK Ltd. Available at:
<http://www.ricardo.com/PageFiles/16317/camless%20engine_V4_LR.pdf> [Accessed on 10 July
2014]
[13] J.W.G. Turner and S.A. Kenchington Lotus Engineering, 2009. Production AVT Development:
Lotus and Eaton's Electrohydraulic Closed-Loop Fully Variable Valve Train System. [Online pdf].
USA: Eaton Automotive. Available at:
<http://bioage.typepad.com/greencarcongress/docs/LotusEaton.pdf> [Accessed on 12 August
2014]
[14] Haq, M.Z., 2011. Volumetric Efficiency of Engines, ME 401: Internal Combustion Engine.
[Online] Bangladesh University of Engineering & Technology. Available at:
<http://teacher.buet.ac.bd/zahurul/ME401/ME401_volumetric_efficiency.pdf> [Accessed on on 27
July 2014]
[15] RGM Racing, n.d. Flow through valves, valve geometry. [Image online] Available at:
<http://rgmracing.free.fr/luc/heywood1/> [Accessed on 26 July 2014]
[16] Vivolo, 2008. Vivolo introduction datasheet [Online pdf] Italy: Sole Shareholder Company.
Available through: Vivoil company website: http://vivoil.ru/pdf/vivoil-XP-0P.pdf [Accessed on 28
May 2014]
[17] Hydra Products, n.d. Hydra Products micro pack hydraulic pump [Online pdf] UK: Hydra
Products Company. Available through: Hydra products company website:
<http://www.hydraproducts.co.uk/Hydraulic-Power-Packs/Micro-Power-Pack/2-Reversible-Micro-
pack.aspx> [Accessed on 20 June 2014]
[18] Parker Hanifin, 2013. Parker Oaler diaphragm accumulator [Online pdf] UK: Parker Hanifin
Corporation. Available through: Parker company website:
<http://www.parker.com/literature/Accumulator%20&%20Cooler%20Division%20-
%20Europe/Accumulators_Paris_English/Diaphragm%20Accumulators,%20ELM%20from%2014
0%20to%20350%20bar,%20EMDC.%20HY10-4002-UK.pdf> [Accessed on 27 June 2014]
[19] Sor Inc., 2012. Pressure switch operating principles [Video online] Available at:
<http://www.youtube.com/watch?v=gC2Hx7n7KY4> [Accessed on 11 June 2014]
[20] RS, n.d. Parker hydraulic filter specifications [Online] UK: RS Component Ltd. Available at:
<http://uk.rs-
online.com/web/p/products/729060/?utm_campaign=applegate.co.uk&utm_medium=referral&utm
_source=applegate.co.uk> [Accessed on 27 June 2014]
[21] SSFlex, 2013. Flexible hydraulic hoses [Online] China: Huaxing Rubber Hose Co Ltd.
Available at: <http://www.flexible-hose.org/flexible-metal-hose/medium-pressure-flexible-
hose.html> [Accessed on 15 August 2014]
[22] Moog servovalve, 2014. Using the Ricardo laboratories. [Moog valve specification] May
2014. Brighton: University of Brighton
MSc Automotive Engineering Page 77 of 93 Adil Karakayis
[23] Moog, n.d. Type 30 nozzle-flapper flow control servovalves [Online pdf] USA: Corporate
Headquarters - Moog Inc. Available at:
<http://www.mylesgroupcompanies.com/moog_pdfs/Moog%2030%20Series%20Catalog.pdf>
[Accessed on 28 May 2014]
[24] Solid solutions supporting excellence, 2014. Solidworks(x64) [Computer program] Solid
solutions management ltd. Available at: < http://www.solidsolutions.co.uk/Get-a-SOLIDWORKS-
Price.aspx> [Accessed on 30 May 2014]
[25] Informer technologies, 2014. Proteus 7 [Computer program] Labcenter electronics. Available
at: <http://proteus.software.informer.com/download/> [17 August 2014]
[26] National Instrument, 2014. NI USB-6008 picoscope [Online] UK: National Instruments
Corporation Ltd. Available at: <http://sine.ni.com/nips/cds/view/p/lang/en/nid/201986> [Accessed
on 18 August 2014]
[27] Papathanasiou, D. 2014. Investigation of the performance characteristics of an Electro-
hydraulic valve for automotive applications. BEng. University of Brighton.
[28] Mobil, 2014. High performance four-stroke motorcycle engine oil product description
[Online] Australia: Exxon Mobil Corporation. Available at: < http://www.mobil.com/Australia-
English/Lubes/PDS/GLXXENPVLMOMobil_Super_4T.aspx> [Accessed on 30 May 2014]
[29] Ebay Inc. 2014. ATmega2560 Mega 2560 -16AU Board (Arduino-compatible) [online]
Available at:
<http://www.ebay.co.uk/itm/201055557274?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1
497.l2649> [Accessed on 13 June 2014]
[30] Daniels, S. 2011. Arduino’s AnalogWrite – Converting PWM to a Voltage [Online] Available
at: <http://provideyourown.com/2011/analogwrite-convert-pwm-to-voltage/> [Accessed on 18 June
2014]
[31] MathWorks, Inc. 2014. MATLAB 2013a. [Computer program] Available at:
<https://www.mathworks.co.uk/downloads/web_downloads> [Accessed on 19 May 2014]
[32] National Instruments Corporation, 2014. LabVIEW [Computer program] Available at:
<http://www.ni.com/download-labview/> [Accessed on 30 June 2014]
[33] Thurlby Thandar Instruments, TTi TG1010A manual [Online] UK: Thurlby Thandar
Instruments Ltd. Available at:
<http://www.ko4bb.com/Manuals/09)_Misc_Test_Equipment/Thurlby/TTi_TG1010A_Function_G
enerator_Instruction_Manual.pdf> [Accessed on 30 June 2014]
[34] KISTLER, 2013. 6121 &6123 pressure transducer specifications [Online] USA: Kistler
Holding AG. Available at: <http://www.kistler.com/us/en/category/sensors-and-
transmitter/pressure/PSEPR/?application&reload=true> [Accessed on 18 August 2014]
[35] Koreisová, G., 2006. Identification of viscous damping coefficient of hydraulic motors [online
pdf] Scientific Papers of the University of Pardubice. Available at:
MSc Automotive Engineering Page 78 of 93 Adil Karakayis
<https://dspace.upce.cz/bitstream/10195/35214/1/Koreisov%C3%A1G_Identification%20of%20vi
scous_SP%20DFJP_2006.pdf> [Accessed on 14 July 2014]
[36] MathWorks, Inc. 2014. MATLAB 2013a SimMechanics Link. [Computer program] Available
at:
<https://www.mathworks.co.uk/products/simmechanics/download_smlink_confirmation.html?conf
irmation_page&wfsid=5623257> [Accessed on 22 May 2014]
[37] Patel, C. 2014. Creating and Masking Subsystems, Simulink. [Video online] Availible at:
<http://www.mathworks.co.uk/videos/creating-and-masking-subsystems-69025.html> [Accessed
on 20 May 2014]
[38] MathWorks, Inc. 2014. MATLAB 2013a SimMechanics. [Computer program] Available at:
<http://www.mathworks.co.uk/products/simmechanics/> [Accessed on 20 May 2014]
[39] MathWorks, Inc. 2014. Ideal Force Sensor. [Online] Available at:
<http://www.mathworks.co.uk/help/physmod/simscape/ref/idealforcesensor.html> [Accessed on 22
May 2014]
[40] MathWorks, Inc. 2014. Simulink-PS Converter. [Online] Available at:
<http://www.mathworks.co.uk/help/physmod/simscape/ref/simulinkpsconverter.html> [Accessed
on 22 May 2014]
[41] MathWorks, Inc. 2014. Ideal Translational Velocity Source. [Online] Available at:
<http://www.mathworks.co.uk/help/physmod/simscape/ref/idealtranslationalvelocitysource.html>
[Accessed on 22 May 2014]
[42] MathWorks, Inc. 2014. Ideal Angular Velocity Source. [Online] Available at:
<http://www.mathworks.co.uk/help/physmod/simscape/ref/idealangularvelocitysource.html>
[Accessed on 22 May 2014]
[43] MathWorks, Inc. 2014. MATLAB 2013a SimHydraulics. [Computer program] Available at:
<http://www.mathworks.co.uk/products/simhydraulics/> [Accessed on 27 May 2014]
[44] Miller, S. 2014. Modeling a Custom Hydraulic Valve, Simulink. [Video online] Availible at:
<http://www.mathworks.co.uk/products/simhydraulics/features.html#customizing-models>
[Accessed on 27 May 2014]
[45] Miller, S. 2014. Modeling a Hydraulic Actuation System, Simulink. [Video online] Availible
at: <http://www.mathworks.co.uk/videos/modeling-a-hydraulic-actuation-system-68833.html>
[Accessed on 27 May 2014]
[46] MathWorks, Inc. 2014. Creating and Simulating a Simple Hydraulic Model. [Online]
Available at: <http://www.mathworks.co.uk/help/physmod/hydro/ug/creating-a-simple-
model.html> [Accessed on 27 May 2014]
[47] MathWorks, Inc. 2014. 4-Way Directional Valve. [Online] Available at:
<http://www.mathworks.co.uk/help/physmod/hydro/ref/4waydirectionalvalve.html> [Accessed on
27 May 2014]
MSc Automotive Engineering Page 79 of 93 Adil Karakayis
[48] Miller, S. 2014. Hydraulic Valve Parameters from Data Sheets and Measured Data, Simulink.
[Video online] Availible at: <http://www.mathworks.co.uk/videos/hydraulic-valve-parameters-
from-data-sheets-and-measured-data-
81734.html?form_seq=conf966&confirmation_page&wfsid=5638471> [Accessed on 28 May
2014]
[49] Thayer, W.J., n.d. Transfer Functions for MOOG Servovalves [Online pdf] EU: Moog Inc.
Available at: <http://www.servovalve.com/technical/new_tb_103.pdf> [Accessed on 16 July 2014]
[50] Douglas, B., 2012. PID Control System. [Video online] Available at:
<http://www.youtube.com/watch?v=UR0hOmjaHp0> [Accessed 9 May 2014]
[51] B15C2 Camshaft Profile, n.d. [Image online] Available at:
<https://docs.google.com/file/d/0BzhpsbuelzqYU01WWlc1dkFxbm8/edit?pli=1> [Accessed on 21
July 2014]
[52] Kumar, G.U. and Namilla, V.R. 2014. Failure Analysis of Internal Combustion Engine Valves
by Using ANSYS. [Online pdf] India: AIJRSTEM. Available at:
<http://iasir.net/AIJRSTEMpapers/AIJRSTEM14-183.pdf> [Accessed on 29 June 2014]
[53] Azadi, M., Roozban, M. and Mafi, A. 2013. Failure Analysis of an Intake Valve in a Gasoline
Engine. [Online pdf] Iran: Iran Society of Engine. Available at:
<http://www.engineresearch.ir/files/site1/user_files_3920b3/admin-A-10-1-88-34991f5.pdf>
[Accessed on 29 June 2014]
[54] Ciccarelli, G. 2012. Engine Performance, MECH 435: Internal Combustion Engines. Queen’s
University. Available at:
<http://me.queensu.ca/Courses/435/files/2.EnginePerformancelecture2013.pdf> [Accessed on 27
July 2014]
[55] Tripod. n.d. Honda Engine Specs. [Online] Available at:
<http://asian_e.tripod.com/Honda_Engine_Specs.htm> [Accessed on 27 July 2014]
[56] Denery, T. and Mirsky, S. 2014. Hardware-in-the-Loop (HIL) Testing of a Position Control
System, Simulink. [Video online] Available at: <http://www.mathworks.co.uk/videos/hardware-in-
the-loop-hil-testing-of-a-position-control-system-81566.html?form_seq=conf1092> [Accessed on
27 May 2014]
MSc Automotive Engineering Page 80 of 93 Adil Karakayis
Appendix A
Graph.17 Motor-pump performance [17]
Graph.18 Parker 10µm oil filter pressure-flow characteristics [20]
MSc Automotive Engineering Page 81 of 93 Adil Karakayis
Graph.19 Moog series 31 servovalve flow datasheet characteristics [23]
MSc Automotive Engineering Page 82 of 93 Adil Karakayis
Figure.52 Schematic of Control box [25] [27]
MSc Automotive Engineering Page 83 of 93 Adil Karakayis
Figure.53 Schematic of main electrical box [25] [27]
MSc Automotive Engineering Page 84 of 93 Adil Karakayis
Figure.54 Schematic of signal amplifier [25] [27]
MSc Automotive Engineering Page 85 of 93 Adil Karakayis
All drawings are in mm.
Figure.55 Solidworks drawing of pipes t-connection bracket [24]
MSc Automotive Engineering Page 86 of 93 Adil Karakayis
Figure.56 Solidworks drawing of HVA and oil filter bracket.a [24]
MSc Automotive Engineering Page 87 of 93 Adil Karakayis
Figure.57 Solidworks drawing of HVA and oil filter bracket.b [24]
MSc Automotive Engineering Page 88 of 93 Adil Karakayis
Figure.58 Solidworks drawing of Pprotective glass frame [24]
MSc Automotive Engineering Page 89 of 93 Adil Karakayis
Figure.59 Solidworks drawing of sink [24]
MSc Automotive Engineering Page 90 of 93 Adil Karakayis
Figure.60 Solidworks drawing of pressure transducer flange [24]
MSc Automotive Engineering Page 91 of 93 Adil Karakayis
Appendix B
MSc Automotive Engineering Page 92 of 93 Adil Karakayis
Appendix C
Figure.61 Plan of the project