Online diagnosis method for uniformity of common-rail oil injectors

Abstract

The invention provides an online diagnosis method for uniformity of common-rail oil injectors. The online diagnosis method includes the following steps: step one, under the condition that pressure in a common-rail pressure storage rail meets requirements, collecting and calculating pressure drop of a main injection action in the pressure storage rail; step two, acquiring a main injection pressure drop reference value of a current work cycle, and dividing the collected and calculated main injection pressure drop by the main injection pressure drop reference value to acquire an injection pressure drop ratio of the common-rail injectors in this time of injection; step three, comparing oil injection capability grade threshold values of a set of the oil injectors according to the determined injection pressure drop ratio of the common-rail oil injectors, determining oil injection capability grade, of the common-rail oil injector, calculated in this time, and using a statistical method to finally determine the oil injection capability grade of the common-rail oil injectors. By the online diagnosis method, oil injector aging degree can be calculated accurately without increasing extra cost.

Description

technical field [0001] The invention relates to the field of internal combustion engines, in particular to a method for diagnosing and evaluating an electronically controlled common rail fuel injector. Background technique [0002] Before installing multiple injectors on the high-pressure common rail system of a diesel engine, the operator needs to use the test bench to group the injectors to select a group of injectors with similar injection characteristics, that is, to inject oil under the same injection pressure and injection pulse width. However, a group of injectors installed on a diesel engine will inevitably have individual differences due to manufacturing, assembly or wear during operation. Some injectors have the same injection pressure and injection pressure. The actual fuel injection volume under the pulse width is larger than the standard fuel injection volume, and the actual injection fuel volume of some injector samples may be smaller, and even serious failures...

AI Technical Summary

Problems solved by technology

The previous solutions all focused on indirect calculation of the actual injected fuel quantity by comparing the effect of injected fuel combustion. These methods all have some shortcomings, because the injected fuel combustion process involves many influencing factors, and the fuel injection is relatively small. The combustion effect caused by the quantity difference is not obvious or the combustion effect cannot amplify the fuel difference, which leads to insufficient accuracy of the calculated actual injection quantity of the injector

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