Method and device for rail pressure simulation during diesel engine start-up

Abstract

The method and device for simulating the rail pressure during the starting process of the diesel engine provided by the present invention, after the rail pressure sensor fails, the rail pressure value output by the rail pressure sensor is determined according to the real rail pressure variation law during the starting process of the diesel engine, that is, the starting process of the diesel engine is simulated The real rail pressure value in the engine makes the real fuel injection quantity more accurate, ensures the normal fuel injection during the starting process of the diesel engine, and improves the success rate of diesel engine starting.

Description

technical field [0001] The invention relates to the field of vehicles, and more specifically relates to a rail pressure simulation method and device during the starting process of a diesel engine. Background technique [0002] The electronically controlled high-pressure common rail system mainly includes four major components: the electronically controlled high-pressure oil pump, the common rail pipe, the electronically controlled fuel injector and the ECU; installation. The rail pressure sensor is at one end of the common rail pipe to monitor the pressure in the rail in real time. [0003] The target fuel injection quantity of the injector is calculated according to the rail pressure value output by the rail pressure sensor and the current fuel injection quantity. At present, when the rail pressure sensor fails, a fixed value or an output value of a fixed MAP is directly used as a rail pressure substitute value. Since the calibrated rail pressure substitution value is re...

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Problems solved by technology

Since the calibrated rail pressure substitution value is relatively large, the injector starts to inject fuel when the real rail pressure is very small during the engine starting process. Such components cause the rail pressure to build up time slowly, and also lead to In the environment, when the fuel with low pressure is difficult to burn, it will absorb the heat in the cylinder and it will not be easy to start

Moreover, when it is difficult to catch fire in a cold environment, the real rail pressure may exceed the rail pressure substitute value during engine start-up, that is, the actual required fuel injection volume is greater than the fuel injection volume corresponding to the rail pressure substitute value, which makes ignition more difficult

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