Embed Size (px)
Citation preview
Rankine cycle,
from thermodynamic equations to road test
Speaker : Thibault Fouquet Co-Author : Julien Roussilhe
Heavy-Duty, On- and Off-Highway Engines 2017
Augsburg, 29/11/2017
Agenda
2
12th International MTZ Conference on Heavy-Duty Engines
3
Rankine equations
Critical point
Supercritical region
Liquid region Superheated
Vapor
region
Te
mp
era
ture
[d
eg
C]
Entropy [kJ/kg/K]
2 phase region
3
4
MECHANICAL WORK
1 bar
20 bar
2
1
Rankine usage nowadays
Industrial, static or quasi static installation
4
Slow variation or low variation in heat power. Easier to size, easier to control in transient
Limited integration constraints
12th International MTZ Conference on Heavy-Duty Engines
Rankine on the road
Vehicle choice
Criteria : Stable use condition / space available
− Long haul heavy truck
Truck mission profile
Mostly constant speed
But variation of engine power
Engine mission profile
High variation of engine mechanical output
High variation of exhaust thermal power
5
Tem
pe
ratu
re T
[°C
] Mass flow [kg/h]
Application for the demotruck : Renault T460 – D11 : 11L wo EGR & TC
~500
~2000
Speed [km/h] Slope [%] Typical engine power [kW]
90 0 100
90 1 180
90 -1 20
90 0 80
12th International MTZ Conference on Heavy-Duty Engines
Waste heat on road
Summary view of losses
Steady state 90 km/h for a truck
6
40% to Powertrain
~30 L/ 100km
30% to exhaust ~300°C
30% to cooling ~90°C
Move forward the truck
Waste Heat with 2 to 4% Rankine cycle efficiency
Waste heat with 5 to 15% Rankine cycle efficiency
Rankine on exhaust could save 1L/100km
12th International MTZ Conference on Heavy-Duty Engines
Rankine integration and performance,
where are we ?
Project organization
7
-System simulation and sizing -Components supply (except expander) -Integration and control -Test
-Truck -Test facilities -Truck data for simulation and integration
-Expander -Expander integration
-Input for expander simulation and control
EHRS
12th International MTZ Conference on Heavy-Duty Engines
Get the understanding of equation
8
Working fluid choice
Scientific reasons : Excel tools
Pragmatism reasons : Compromise vs current knowledge and potential
impact on the truck
Preliminary selection of fluids with exhaust and coolant as temperature sources
Easy comparison with known hypothesis
Sensitivity to boundary conditions can be assessed and understood
12th International MTZ Conference on Heavy-Duty Engines
Evaluation of Rankine performance
Mission profile impact (mech coupling)
Target : Renault trucks mission profile + steady state
− 33 tons total weight
Evaluation of Rankine performance
9
Altitude [m]
Engine [kw] Exhaust [kw]
Cooling margin [kW]
Rankine output [kW] Vs Potential [kW]
Cooling system fully
used by the engine]
time
No need of mech power
12th International MTZ Conference on Heavy-Duty Engines
Increase model complexity
10
Truck simulation with transient capability
Vehicle system model
Final fluid choice + Rankine sizing Ethanol with fuel saving expected between 1,5 and 3%
Rankine system model
Engine waste heat system
model
12th International MTZ Conference on Heavy-Duty Engines
Visual layout
11
EATS Engine Exhaust boiler bypass valve
Boiler
Expander bypass valve
Expander
EHPG control unit
80°C
90°C
330°C
230°C
140°C
95°C
130°C
Pressure vessel
Pump
Condenser
12th International MTZ Conference on Heavy-Duty Engines
Turn model into reality
12
Bench building
Hot source
Cold source
Rankine system
ICE EATS
7
ICE break
1
2
Expander break
8
9
3
4
Temperature control
1: Evaporator
2: Expander
3: Condenser
4: Pump
5: Pressure vessel
6: Control unit
7: Exhaust bypass
8: Expander bypass
9: Clutch
12th International MTZ Conference on Heavy-Duty Engines
Close to truck setup
Connection to the engine
13
Automatic control validated along reference cycle
ICE EATS
7
ICE break
1
2 8
9
3 4
Temperature
control
10
12
1) Evaporator
2) Expander
3) Condenser
4) Pump
5) Pressure vessel
6) Control
7) Exhaust bypass
8) Expander bypass
9) Clutch
8) PRV
9) Deaerator
10) Filter
12th International MTZ Conference on Heavy-Duty Engines
One word on control
14
Control creation process
Control architecture
Control System model Steps
GT GT First assessment of performance. No cosimulation to reduce computation time
Simulink GT Preparation of the command to be used in rapid prototyping. Clear split between the model
and the control
Simulink Bench Same Simulink than the one used in simulation
Expander
model
Heat transfer
with boiler
model
Flow split Energy at
exhaust
Energy at
boiler
Ethanol flow
in boiler
Cooling
model
Input data
Engine
CAN +
rankine
sensors
~20 diagnosis
+ 3 back-up mode
Thermo-
management
Actuator
control Manager
Pump
model
Ethanol
flow
Pump
speed
Valve
model
Flow
split
Valve
Position
Stateflow Expander
status
Exp
Bypass
Position
Expander
status Stateflow
Clutch
Position
Cooling
model
Condenser
status
Pressure
vessel &
Cooling
pump
Model based + PID
Diagnostic already included
Compatible with standard µc
12th International MTZ Conference on Heavy-Duty Engines
Make it fits
15
From bench to truck
Constraints ….
Reality
Without Rankine
With
Rankine
Integration not visible
No impact on fuel tank capacity
12th International MTZ Conference on Heavy-Duty Engines
Adventure on the road
Road test synthesis
20 journeys
2800 km
700 Liters of fuel
No trailer & trailer 20t – 26t – 30t
Rankine ON & OFF
Autonomous system control
16
System control validated in various real drive situation
Confirmation of component sizing
More than 10 L of diesel saved already !
12th International MTZ Conference on Heavy-Duty Engines
Measurement of performance
17
Chassis dyno test
Trailer load simulated by chassis dyno
Face cooling wind simulated by fan
Diesel flowmeter
Automatic driver
Temperature regulated
test cell
1
1
2
3
2
3
4 4
Fue
l co
nsu
mp
tio
n
[L/h
]
Rankine ON
Rankine OFF
For the first time fuel economy can be measured on the bench – up to 2,7% on steady state
12th International MTZ Conference on Heavy-Duty Engines
Post-processing
18
Faurecia internal tools
Matlab based
Simulation / test result analysis
Automatic analysis
12th International MTZ Conference on Heavy-Duty Engines
Model correlation
19
Simulation tasks left
Correlation results
Model creation Correlation Extrapolation Prototype
Energy correlation reached after model
calibration
12th International MTZ Conference on Heavy-Duty Engines
Extrapolation of performance
20
Ref cycle – transient simulation
1,5
2
2,5
3
3,5
Demotruckbaseline
Boiler with higherperformance
Expander nextgeneration
Improvement oncontrol
External cooling
Fue
l sav
ing
[%]
Fuel saving improvements
3 % reachable on hilly mission profile
Flat road could bring an additionnal 1 point of fuel saving. EGR also, but with more complexity and cost
12th International MTZ Conference on Heavy-Duty Engines
Extrapolation of performance
21
Zoom on best case vs baseline on simulation
Better efficiency Better cooling
12th International MTZ Conference on Heavy-Duty Engines
Project constraint
Internal target to fit the demotruck within ~1year
22
2016 2017
M M Truck
reception
Roller
bench tests
JAN FEB MA APR MA JUN JUL AU SEP OCT NO DEC JA FEB MA AP MA JUN JUL
Model &
architecture
selection
Part Purchasing
and CAD bench
preparation
Truck
inte-
gration
Control law definition
Setup in
engine
test cell
Road test
12th International MTZ Conference on Heavy-Duty Engines
Conclusion
23
System Rankine on a truck by Faurecia
System integrated as retrofit without impact on tank capacity
System understanding and control capability proven
Rankine performance demonstrated on real truck usage
Rankine perspective
Technology can be implemented with noticeable fuel saving,
performance demonstrated on real road
Price vs 2 years ROI is a reachable equation based on our sizing
12th International MTZ Conference on Heavy-Duty Engines
24
Thank you for your attention
Time for question
12th International MTZ Conference on Heavy-Duty Engines
