Analysis of injection rate characteristics of fuel injection systems in IDI diesel engines using an enhanced numerical simulation code

For effective reduction of noise level and nitrogen oxide content in exhaust fumes of diesel engines, multistage fuel injection is used in combination with control of the front edge shape of the main injection. At the Moscow Automobile and Road Construction State Technical University (MADI), a method of control of the injection rate shape using an electric impulse was proposed, which was applied to the electromagnet of the control valve of the injector of the common rail fuel system. A computational and experimental analysis of the possibility of boot-type injection rate shape was carried out. The studies involved three most used designs of the common rail injector (CRI): CRI 1 featuring a control valve with shut-off cone and piston; CRI 2 consisting of a flat-lock control valve and a needle, which does not overlap the drain when the needle is in the highest position; CRI 3 with an injector that partially overlaps the drain. It was established that friction in the control valve piston and the guide surface pair of CRI 1 complicated the implementation of the boot-type injection rate due to its smoothing. CRI 2 and CRI 3 provide boot-type injection rate at different pressures in the fuel accumulator. The CRI 3 example shows that the instability of fuel supply during boot-type injection rate is comparable with that of fuel pre-injection, which is widely used in the organization of the common rail diesel engines working process.

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Study of Fuel Temperature Effects on Fuel Injection, Combustion, and Emissions of Direct-Injection Diesel Engines

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3019006 ◽

2008 ◽

Vol 131 (2) ◽

Cited By ~ 12

Author(s):

Gong Chen

Keyword(s):

Diesel Engine ◽

Diesel Engines ◽

Temperature Effects ◽

Liquid Fuel ◽

Fuel Injection ◽

Direct Injection ◽

Injection Rate ◽

Fuel Temperature ◽

Injection Parameters ◽

Medium Speed

The influence of inlet liquid fuel temperature on direct-injection diesel engines can be noticeable and significant. The work in this paper investigates the effects of inlet fuel temperature on fuel-injection in-cylinder combustion, and output performance and emissions of medium-speed diesel engines. An enhanced understanding and simplified modeling of the variations in the main fuel-injection parameters affected by inlet fuel temperature are developed. The study indicates that the main injection parameters affected include the injection timing at the injector end relative to the injection-pump actuation timing, the fuel-injection rate, the fuel-injection duration, and the injection spray atomization. The primary fuel temperature effects on the injection parameters are from the fuel bulk modulus of elasticity and the density with the fuel viscosity less significant as the injector-nozzle flow is usually in a turbulent region. The developed models are able to predict the changes in the injection parameters versus the inlet fuel temperature. As the inlet fuel temperature increases, the nozzle fuel-injection-start timing is predicted to be relatively retarded, the injection rate is reduced, and the needle-lift duration is prolonged from the baseline. The variation trends of the engine outputs and emissions versus fuel temperature are analyzed by considering its consequent effect on in-cylinder combustion processes. It is predicted that raising fuel temperature would result in an increase in each of CO, HC, PM, and smoke emissions, and in a decrease in NOx, and may adversely affect the fuel efficiency for a general type of diesel engine at a full-load condition. The experimental results of the outputs and emissions from testing a medium-speed four-stroke diesel engine agreed with the trends analytically predicted. The understanding and models can be applied to compression-ignition direct-injection liquid fuel engines in general.

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Neural Network Based Identification of Fuel Injection Rate Profiles for Diesel Engines

2020 9th International Conference on Industrial Technology and Management (ICITM) ◽

10.1109/icitm48982.2020.9080367 ◽

2020 ◽

Author(s):

Eero Immonen ◽

Mika Lauren ◽

Lassi Roininen ◽

Simo Sarkka

Keyword(s):

Neural Network ◽

Diesel Engines ◽

Fuel Injection ◽

Injection Rate ◽

Fuel Injection Rate

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Study of Fuel Temperature Effects on Fuel Injection, Combustion and Emissions of Direct-Injection Diesel Engines

Design and Control of Diesel and Natural Gas Engines for Industrial and Rail Transportation Applications ◽

10.1115/icef2003-0752 ◽

2003 ◽

Author(s):

Gong Chen

Keyword(s):

Diesel Engines ◽

Temperature Effects ◽

Liquid Fuel ◽

Fuel Injection ◽

Direct Injection ◽

Injection Rate ◽

Fuel Temperature ◽

Injection Parameters ◽

Medium Speed ◽

Performance And Emissions

The influence of inlet liquid fuel temperature on direct-injection diesel engines can be noticeable and significant. The work in this paper investigates the effects of inlet fuel temperature on fuel injection, in-cylinder combustion, and performance and emissions of medium-speed diesel engines. An enhanced understanding and simplified modeling of the variations in main fuel injection parameters affected by inlet fuel temperature are developed. The study indicates that the main affected injection parameters include the injector injection timings, the fuel injection rate, the fuel injection duration, and the injection spray atomization. The primary fuel temperature effects on the injection parameters are from the fuel bulk modulus of elasticity and the density with the fuel viscosity less significant as the injector nozzle flow is in a turbulent region. The developed models can predict the changes in the injection parameters versus fuel temperature. As inlet fuel temperature increases, the nozzle fuel-injection-start timing is predicted to be retarded, the injection rate to be reduced, and the needle-lift duration to be prolonged from the baseline. The variation trends of the engine performance and emissions versus fuel temperature are analyzed by considering its consequent effect on in-cylinder combustion processes. It is predicted that raising fuel temperature would result in an increase in CO, HC, PM and smoke emissions, and in a decrease in NOx. The experimental results of the output performance and emissions from testing a medium-speed four-stroke diesel engine agreed with the trends analytically predicted. The understanding and models developed can apply to compression-ignition direct-injection liquid fuel engines in general.

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