PROCEEDINGS OF THE INSTITUTE OF VEHICLES 5(109)/2016

69

Denys Meshkov

1, Dmytro Samoilenko

2, Andriy Prokhorenko

3

PERSPECTIVES OF USING A LINEAR PIEZOELECTRIC

CONVERTER IN A FUEL INJECTION SYSTEM OF COMMON RAIL

1. Introduction

Following research about current trends in development of diesel engine fuel

delivery systems it was established that Common Rail fuel delivery system has no

alternatives as solution for improvement of technical and economic characteristics of

modern diesels [1-3]. It is known that the most famous world producers of fuel delivery

systems and their components are Bosch, Siemens and Denso. But fuel delivery systems

from mentioned companies have high cost for components. Moreover, there are some

difficulties can be found in adaptation of commercial fuel delivery system for particular

engine. Such adaptation usually includes the development of new algorithm for engine

management systems [4]. Services for adaptation of fuel delivery system cost a lot and

algorithms are know-how from the producers.

It is known that one of the most responsible and expensive components in Common

Rail fuel delivery system is fuel injector that currently has an electronic control.

Moreover inside the injector there is a crucial component called converter (actuator). A

lot of engine’s parameters depend on characteristics of this component [5]. At present

two types of actuators are mostly widespread: solenoid valve and piezoelectric converter

[2, 3]. To be successfully used in modern fuel delivery system, actuator must fulfill

following requirements: fast response and high developed force, low expenditure of

energy, low cost, free availability of components needed for production, maximum

design simplicity and service life.

Thus, new design of convector (actuator) for diesel engine’s fuel injector needs to

be developed and used in new generation of fuel delivery systems. The first step in such

R&D work is search for optimal design parameters as well as development of new

methods used for adaptation of such system to different types of engines.

2. Design features and simulations of the prototype of piezoelectric converter for

fuel injector

Research works devoted to development of fuel delivery systems for diesel engines

managed by electronic control are presented in [8-10].

The present study concerns creation of new design of actuator that can be used in

fuel injector of Common Rail system as an alternative solution to existing one. Linear

piezoelectric converter (LPC) is offered as actuator for mentioned purpose. Three

different designs were developed as result of R&D work. They are presented in Fig.1.

1 Denys Meshkov, Ph.D. Eng.; Internal Combustion Engines Department, National Technical University

“KhPI” 2 Dmytro Samoilenko, Ph.D. Eng.; Department of Combustion Engines, Institute of Vehicles, Warsaw

University of Technology 3 Andriy Prokhorenko, Prof. D.Sc.; Internal Combustion Engines Department, National Technical University

“KhPI”

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Fig.1. New designs of Lineal Piezoelectric Converter (LPC)

As it can be seen from Fig.1 the linear piezoelectric converter was offered as

actuator in such system [11]. The main distinctive feature of such actuator is that offered

actuator is made as one piece unit. Design presented in Fig.1 was developed in

cooperation with the laboratory of microelectronics from Kiev Polytechnic University.

The main parameters of LPC in comparison to existing solutions are presented in

Table 1.

Table 1. Comparative characteristics of converters

№ Parameter Solenoid

(CR I,II)

Piezo converter

(CR III) LPC

1. Speed of response, ms 0,2 0,1 0,1

2. Stroke, mm 0,05 0,04 0,05

3. Maximum force, N 100 500 400

4. Energy consumption, V 60 400 150

5. Price + - +

6. Reliability + - +

7. Simplicity of design - - +

8. Stability of characteristics - + +

It can be seen from Table 1 that LPC has sufficient parameters to be used in

Common Rail fuel injectors. At the same time LPC has lower cost, simple design as well

as can be produced from widespread materials when to compare with commercial

solutions. Moreover, life tests showed that Lineal Piezoelectric Converter has high

degree of reliability.

Developed LPC is made as piezoelectric oscillator with an active part, made of

polarized material in a form of a rectangle plate as it shown in Fig. 1. On the main

surface of the plate there is a continuous, joint electrode with a lead for plugging-in to

the source of energy. LPC is fixed in a holder that serves as protection shield for the

linear converter and at the same time the holder is a body for installation of LPC inside

the injector. Movable part is made like an electric connector supported with a teeth that

are pressed through anti-wear ceramic layer – pad to the middle of the side edge. The

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valve rod is fixed at the base of the electronic connector through the resiliently pressed

disk. The prototype has following dimensions for the piezoelectric element: length L= 62

mm, width B = 30 mm and thickness A = 10 mm. The sample is made of material CTBS

- 3. To measure the force that can be developed by LPC special bench was made. Test

bench is shown in Fig. 2.

Fig. 2. Test bench with prototype of LPC

During experiments on the test bench the following main results were obtained: the

maximum effort 400 N, speed of operation 0,1 m/s; maximum shift 0,05mm. Also, the

dependence between generated force and travel was established. This dependence is

shown in Fig. 3. As seen from Fig.3 there is linear dependence between generated force

and travel.

Fig. 3. The dependence between generated force and travel at new design of LPC

For checking possibility of using developed LPC in fuel injectors the modified

mathematical model was developed [8, 10] that is shown in Fig.4. The model was

realized in MatLab/Simulink environment and helps to simulate and visualize all the

processes that happen inside the injector: changing in pressure at different chambers,

lifts (travels), speeds and accelerations of moving elements and so on.

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Fig. 4. Mathematical model of injector equipped with LPC

(MatLab/Simulink environment)

Next step in research work was adaptation of the design of commercial fuel injector

for installation new LPC unite inside. This adaptation included optimization for main

parameters of design as well as characteristics of adjustments in order to provide

working capacity in the full range of engine crankshaft rotation speeds and engine loads.

For this purpose the new construction of injector with hydraulic tappet and control

camera was developed. The main characteristics of the developed injector are shown in

Fig. 5. The choice of the main design parameters was made using the method of

researches of the space of parameters. The range of variable values is also shown in table

in Fig. 5.

Fig. 5. Prototype of common rail injector equipped with new LPC

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Simulations results in the form of dependences of fuel delivery rate from the

duration of the control pulse at different pressures in the rail are shown in Fig. 6.

Fig. 6. Dependences of fuel delivery rate from the duration of the control pulse

Next stage of research work was devoted to development of primary matrix of

control values for particular diesel engine. An experimental investigation was conducted

on a four-stroke four cylinder turbocharged diesel engine. The short specification of the

engine is shown in Table 1.

Table 1. Engine specification

Rated power 125 kW

Engine speed at rated power 2000 rpm

Number of cylinders 4 in line

Bore 120 mm

Stroke 140 mm

Boost system Turbocharger

with intercooler

Displacement 6.3 liters

Specific fuel consumption (rated

power mode)

224 g/kWh

Length 1769 mm

Width 826 mm

Height 1167 mm

In order to develop primary matrix of control values for tested diesel engine the

main parameters were measured during tests: fuel delivery rate and injection advanced

angle. Test bench was equipped with measuring equipment from AVL company that

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allowed to visualize the process of measurements in real-time mode. Such sensors as

crankshaft positioning sensor, fuel injector’s pressure sensor and in-cylinder pressure

sensors were installed for measurements. Scheme of the test bench is presented in Fig. 7.

On basis of data obtained in experiments as well as results of mathematical

modeling of injector with LPC the new method of synthesis of fuel delivery electronic

system was offered. Values for matrix of pressures in the Fuel Rail and duration of the

signals for injectors were obtained using graphical method that is shown in Fig. 8. It’s

important to mention that initial values will be specified further.

3. Conclusion

Thus, an alternative variant of convector was offered for application in Common

Rail fuel injectors. New linear piezoelectric convector has the same amount of useful

characteristics but is cheaper and his design is simple when to compare with identical

characteristics of stacked piezoelectric column. It was found during experimental

research that developed construction of injector provides: fuel injection with the pressure

from 80 to 180 MPa in fuel rail (accumulator) and multi phase fuel injection with the

stability of feeding 0,5 mm3

/operation. Fuel consumption for injector actuation is

1…10% of the rated cyclic feeding.

Fig. 7. Scheme of the experimental test bench

Needle motion sensor

Sensor of TDC

Amplifiers

Software PowerGraph 3.2 Pro

Software DieselAnalyse 1.3

MatLab files

Sensor of the

crankshaft rotation angle

In-cylinder pressure sensor

AVL 8QP505c

ADC L-Card 783-86

Engine

Fuel pressure sensor AVL 5QP6002

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Fig. 8. Matrixes for application in diesel engine management system

References:

[1] Meyer Steffen S.: Piezogesteuertes Forschung-Einspritzsystem fuer

direktenspritzende PKW-Dieselmotoren, Hannover, 2004,

[2] Hummel K., Böcking F., Groß J., Stein J., Dohle U.: Generation Pkw-Common-

Rail von Bosch mit Piezo-Inline-Injektoren , MTZ: Motortechnische Zeitschrift,

2004, Vol. 3, pp. 180-189,

[3] Kammerdiener T., Bürgler L.: Ein Common-Rail-Konzept mit druckmodulierter

Einspritzung, MTZ: Motortechnische Zeitschrift., 2000, Vol. 4, pp. 230-238,

[4] Melbert J., Raupach C., Wang Q. :Piezoaktuatoren in Kfz–Einspritzventilen.

Modelling und adaptive Vervahren zur Dosieroptimierung, MTZ:

Motortechnische Zeitschrift, 2006, Vol. 3, pp. 190–196.

[5] Böcking F., Dohle U., Hammer J.: PKW-Common-Rail-Systeme für künftige

Emissionsanforderungen, MTZ: Motortechnische Zeitschrift, 2005, Vol. 7, pp.

552-557.

[6] Kazimierz L. :Mathematical modeling of the injection process run in common rail

system by “moving volumetric element” method , Journal of KONES Internal

Combustion Engines, 2004, Vol. 11, pp. 3-4.

[7] Dietz M., Nester U., Lambert L., Brüggemann D.: Der neue Common-Rail-

Dieselmotor mit Direkteinspritzung fur den smart. Teil 2: Verbrennung und

Motormanagement, MTZ: Motortechnische Zeitschrift, 1999, Vol. 12, pp. 838-

848.

[8] Прохоренко А.П., Самойленко Д.Е., Мешков Д.В.: Математическая модель

процесса топливоподачи системой Common Rail с пьезоэлектрической

форсункою, Вісті Автомобільно-дорожнього інституту: Науково-

виробничий збірник, 2009, Vol. 8, pp. 6–12.

[9] Паливний інжектор/ Пат. 9799 U України, F02M51/06, F02M47/00. / Коваль

В.С., Лавріненко В.В., Марченко А.П., Мешков Д.В., Хорунжий В.М. – №

u200503134; Заявл. 05.04.2005; Опубл. 17.10.2005 Бюл. № 10/2005.

[10] Марченко А.П., Прохоренко А.А., Мешков Д.В.: Математическое

моделирование процессов в электрогидравлической форсунке системы

Common Rail в среде MATLAB/Simulink, 2006, Vol. 1, pp. 98-101.

[11] Марченко А.П., Прохоренко А.А., Мешков Д.В.: Выбор рациональных

конструктивных параметров опытной топливной форсунки типа Common

Rail быстроходного дизеля, Двигатели внутреннего сгорания, 2007,

Vol. 1, pp. 68 – 78.

= (Х, n) рак = (Х, n) Θ = (Х,

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Abstract

The present study concerns creation of new design of actuator that can be used in

fuel injector of Common Rail system as an alternative solution to existing one. Linear

piezoelectric converter (LPC) is offered as actuator for mentioned purpose. The main

distinctive feature of such actuator is that it is made as one piece unit. Design was

developed in cooperation with the laboratory of microelectronics from Kiev Polytechnic

University. New linear piezoelectric convector has the same amount of useful

characteristics but is cheaper and its design is simple when to compare with identical

characteristics of stacked piezoelectric column. Developed construction of injector

provides: fuel injection with the pressure from 80 to 180 MPa in the fuel rail and multi

phase fuel injection with the stability of feeding 0,5 mm3

/operation. Fuel consumption

for injector actuation is 1…10% of the rated cyclic feeding.

Keywords: linear piezoelectric converter, compression-ignition engine

PERSPEKTYWY ZASTOSOWANIA LINIOWYCH PRZETWORNIKÓW

PIEZOELEKTRYCZNYCH W UKŁADACH ZASILANIA COMMON RAIL

Streszczenie

Niniejszy artykuł dotyczy nowej konstrukcji urządzenia uruchamiającego, które

może być zastosowane w układach wtryskowych typu Common Rail jako rozwiązanie

alternatywne do istniejących. W tym celu zaproponowano wykorzystanie liniowego

przetwornika piezoelektrycznego (LPP). Główną cechą charakterystyczną tego

urządzenia jest jego wykonanie jako zespołu jednoczęściowego. Projekt został

opracowany we współpracy z Laboratorium Mikroelektroniki Politechniki Kijowskiej.

Nowy liniowy przetwornik piezoelektryczny w porównaniu z przetwornikiem w postaci

kolumny piezoelektrycznej ma takie same właściwości użyteczne, ale jest tańszy, a jego

konstrukcja prostsza. Wtryskiwacz wyposażony w opracowaną konstrukcję zapewnia

wtrysk paliwa przy ciśnieniu w zasobniku od 80 MPa do 180 MPa oraz możliwość

prowadzenia wtrysku wielofazowego z dawką paliwa 0,5 mm3/cykl. Ilość paliwa

zużywanego na aktywację wtryskiwacza wynosi od 1% do 10% nominalnej dawki

wtryskiwanego paliwa.

Sіowa kluczowe: liniowy przetwornik piezoelektryczny, silnik o zapłonie samoczynnym