Method for estimating an hydraulic dwell time between fuel injection pulses which corrects for injection timing delays

Abstract

An embodiment of the invention provides a method for estimating an hydraulic dwell time between fuel injection pulses which corrects for injection timing delays. The method is used for estimating an hydraulic dwell time between a first injection pulse (P) and a second injection pulse (M) performed by a fuel injector (12) of an internal combustion engine (10). The method comprises the steps of: determining a value (DTe1) of an electric dwell time between the first injection pulse (P) and the second injection pulse (M); estimating a value (ICDP) of an injector closing delay between an instant in which an electric closing command of the first injection pulse (P) is generated and an instant in which the fuel injector (12) closes; estimating a value (IODM) of an injector opening delay between an instant in which an electric opening command of the second injection pulse (M) is generated and an instant in which the fuel injector (12) opens. The method then calculates a value (DTh) of the hydraulic dwell time as a function of the electric dwell time value (DTel), of the injector closing delay value (ICDP) and of the injector opening delay value (IODM).

Description

technical field [0001] The invention relates to a method for estimating the hydraulic dwell time between a first injection pulse and a second injection pulse carried out by a fuel injector of an internal combustion engine of a motor vehicle. Background technique [0002] It is known that most internal combustion engines, and especially diesel engines, now have fuel injection systems. [0003] A conventional fuel injection system includes a fuel rail and a plurality of electrically controlled fuel injectors hydraulically connected to the fuel rail through respective feeding conduits. [0004] Each fuel injector generally includes a fuel inlet, a fuel outlet, and a movable needle that repeatedly opens and closes the fuel outlet to inject fuel into the engine in a plurality of discrete injection pulses. [0005] The movable needle is actuated by means of a dedicated actuator, typically a solenoid or piezoelectric actuator, driven by an electric circuit controlled by an engine ...

AI Technical Summary

Problems solved by technology

[0021] The disadvantage of these two strategies is that due to the mechanical characteristics of the fuel injector, especially the mechanical characteristics of the solenoid injector, the moment when the ECU generates the electric opening command is inconsistent with the moment when the movable needle actually opens the fuel injector, and the ECU generates The timing of the electrical close command is also inconsistent with when the movable needle actually closes the fuel injector

[0022] Thus, the use of electrical dwell time as an inlet parameter to the above-mentioned mapping or mathematical equation can still cause large errors in the estimation of the pressure value in the fuel injector inlet, resulting in a corresponding error in the injected fuel quantity

Images