非失火状态下柴油机半阶次抖动特性分析OA北大核心

In order to optimize the idle shake issue for a diesel engine in non-misfire state,the half-order harmonic of engine vibration was analyzed.Based on the"source-path-response"model and the"fishbone diagram"method,the engine operation stability analysis and combustion difference analysis were carried out.The root cause of the half-order shake issue was that the difference in the indicated mean effective pressure(IMEP)and combustion excitation difference for paired cylinder which resulted from the slight difference in the fuel injection volume of cylinders make the stability of torque and speed fluctuations slightly worse,thus the half-order shake issue occurred.Based on the engineering practice,a balanced control method for fuel injection was adopted.This method can balance the differences in combustion excitation torque and significantly suppress the half-order shake energy,with the vibration velocity of diesel engines optimized by about 80.6%,and the issue is resolved successfully.This method is applicable to all direct injection diesel engines in non-misfire state,and it can stay high stability even after more severe wear of fuel injector for long-term operation.