Method of controlling a fuel injector

Abstract

The invention relates to a method for controlling fuel injectors. The method is characterized by comprising the following steps that (1) after the injectors finish injecting, reverse electromotive force signals at the tail end of a driving voltage are captured, and first-order and second-order differential signals of the reverse electromotive force signals are solved; (2) feature information of aseating point of a needle valve is extracted, and turn-off delay time of the injectors is calculated; (3) the negative maximum value of the reverse electromotive force second-order differential is used for representing the opening degree of each injector and accordingly whether the injector is turned on or not can be judged; (4) in accordance with the characteristic value of the opening degree ofeach injector, the zero oil amount pulse width of the injector after ageing can be reversely deduced, and turn-on delay time is solved through the zero oil amount pulse width; (5) the fuel injection amount is calculated; (6) oil amount estimation learning tables corresponding to all the injectors are established, and the oil amount learning tables of the injectors are continuously updated; and (7)after learning is completed, the learnt injection pulse width is reversely checked. By adoption of the method, the control performance requirement of small oil amount consistency of the injectors canbe met and thus repeated small oil amount injection needs can be satisfied.

Description

technical field [0001] The invention relates to a method for controlling a fuel injector, which belongs to the technical field of engine fuel injector control. Background technique [0002] The introduction of stricter emission regulations in my country (including restrictions on cost, fuel consumption and pollutants) is becoming a driving force for changes in the engine market. Considering the lower particle emission, the engine needs a more advanced control strategy to adapt to it. In order to achieve the goal, it is necessary to improve the injection accuracy of the injector at high rail pressure or multiple injections. Therefore, a new engine fuel injection control technology is needed to improve the new performance requirements of injector operation consistency and overcome the influence due to the large variance boundary of injector fuel volume. [0003] Chinese patent application CN201110091678, Method for Controlling Electromagnetic Fuel Injector (Marelli Corporati...

AI Technical Summary

Problems solved by technology

However, in real vehicle operation, the voltage disturbance noise is very large, even with optimized low-pass filtering, it is often difficult to avoid the influence of noise

These noises will affect the inflection point of the first-order differential of the voltage, causing multiple interference inflection points of the voltage signal

At the same time, under some special working conditions, the first-order differential inflection point (second-order differential zero point) may last for a long time, which will lead to the inability to correctly determine the closing time of the injector, so this method can only be used in laboratory environments or ideal state

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