A Method for Determining Acceleration Factor Interval of Electronically Controlled Injector of Diesel Engine Based on Life Theory Calculation

Abstract

The invention provides a method for determining an interval of an acceleration factor of a diesel engine electronic control fuel injector based on lifetime theoretical calculation. The method comprises the following steps: firstly, carrying out mechanism analysis, and determining a potential loss type failure mechanism in the whole life period of all the lowest conventional layer units of the diesel engine electronic control fuel injector and a sensitive stress of the diesel engine electronic control fuel injector; secondly, determining a weak link; thirdly, carrying out failure mechanism acceleration analysis; fourthly, carrying damage calculation; fifthly, carrying out load spectrum equivalent analysis; sixthly, determining an acceleration test load spectrum; seventhly, determining the interval of a unit acceleration factor; and eighthly, determining the interval of a comprehensive acceleration factor of a product. The method provided by the invention is based on a lifetime calculation model, a solution is provided for determination of the interval of the acceleration factor of the diesel engine electronic control fuel injector while uncertainty influence of model parameters and synergistic effect of multiple stresses and multiple failure mechanisms are considered, and method support is provided for reliability verification of the product with a long life index.

Description

technical field [0001] The invention belongs to the field of accelerated life test design, in particular to a method for determining the acceleration factor interval of an electronically controlled fuel injector of a diesel engine based on theoretical calculation of life. Background technique [0002] The electronically controlled fuel injector of diesel engine is the most critical and complicated part in the common rail fuel system. Its function is to inject the fuel in the high pressure fuel rail at an optimal rate by controlling the opening and closing of the solenoid valve according to the control signal sent by the ECU. The fuel injection timing, fuel injection quantity and fuel injection rate are injected into the combustion chamber of the diesel engine. Each set of electronically controlled fuel injector for diesel engine is composed of seven subsystems including needle valve coupling, control plunger assembly, ball valve assembly, armature assembly, coil assembly, in...

AI Technical Summary

Problems solved by technology

[0003] Diesel engine electronically controlled fuel injectors are products with long life indicators. Due to their high price, it is difficult to reduce the test time by increasing the sample size. The only way to reduce the test time is to increase the test stress level, thereby reducing costs; however, diesel engine electronic control The working environment of the injector is relatively complicated, and its failure is the result of multiple failure mechanisms, which makes it difficult to determine the acceleration factor

At present, the multi-stress accelerated life test is based on statistics, and the acceleration factor of the accelerated life test of the product is determined by the method of assuming the product life distribution. The specific information of the product is less required, but a large number of samples are required for the test. For the price Expensive and small number of electronically controlled injectors for diesel engines are difficult to deploy

For the method of determining the acceleration factor based on the mechanism model, it is only applicable to the condition of single mechanism and single stress at present, and there is no complete method for determining the acceleration factor based on forward design under the condition of multi-stress and multi-mechanism

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