Shutdown pressure relief control method and device for fuel system

Abstract

The invention relates to the technical field of automobile engine control, and discloses a shutdown pressure relief control method and device for a fuel system. The fuel system comprises an engine, a fuel rail and a fuel injector, wherein the fuel injector can inject fuel in the fuel rail into the engine. The shutdown pressure relief control method of the fuel system comprises the steps that after the engine obtains a shutdown signal, the fuel rail is in a dynamic pressure relief stage between idle rail pressure and engine stalling, and in the dynamic pressure relief stage, the fuel injector conducts multiple times of injection pressure relief, wherein each injection pressure relief comprises n times of injection, the first (n-1) times are empty injection, and the nth time is non-empty injection; and the stage between the engine stalling and the moment when the fuel rail is in the shutdown rail pressure is a static pressure relief stage, and in the static pressure relief stage, the fuel injector performs empty injection until the rail pressure is reduced to the shutdown rail pressure. The dynamic pressure relief stage is set, the rail pressure can be quickly reduced to the shutdown rail pressure within a short time after the engine obtains the shutdown signal, the pressure relief time is short, the number of times of injection of the fuel injector is small, and the service life is long.

Description

technical field [0001] The invention relates to the technical field of automobile engine control, in particular to a fuel system shutdown pressure relief control method and a control device thereof. Background technique [0002] The fuel injector of the common rail fuel system in the traditional commercial vehicle field is a constant return fuel injector, that is, whether the fuel injector is working or not, there is oil return. As research has found, diesel engines with higher horsepower and higher rail pressure (high horsepower usually refers to a power exceeding 441.3kW, and ultra-high rail pressure usually refers to a rail pressure control range exceeding 2000bar) will more effectively save fuel consumption and reduce pollutants emission. In order to ensure the fuel supply efficiency of the ultra-high rail pressure fuel system (mainly by reducing the rail pressure loss caused by the frequent oil return of the injector), the ultra-high rail pressure fuel system usually u...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is: because the power-on pulse width is very short (generally around 450μs at idle speed), the pressure relief effect is limited, and the fuel injector can only be driven when the engine has no speed, so the pressure relief time is long ;At the same time, because each shutdown will drive the fuel injector thousands of times, this control technology has high requirements on the service life of the fuel injector, and the normal opening times of the fuel injectors are the same as the opening times of the regular oil return injectors. several times

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