Reseach On Speed Control Strategy Of Diesel Engine With Electronic Unit Pump System

Electronic unit pump fuel system has the advantage of simple structure,high reliability and the fuel injection quantity and timing can be controlled flexibly.It could effectively improve the fuel economy and reduce pollutant emission of diesel engine that it will have promising application in marine power field.Diesel engine,which is a nonlinear,big delay,time-varying,uncertainty and complex systems,is difficult for conventional PID algorithm to adapt to control requirements.The PID parameter setting process is complex and is a big workload.Because of manufacturing error,parts depreciation and other reasons,it makes the different fired and work between different cylinder,that result in fluctuating speed,bad NVH and power,economy.On base of analyzing fuzzy control and PID control,fuzzy adaptive PID controller is designed with speed deviation and deviation change as input,which use fuzzy rules adaptive correct three parameters of PID control.According to the speed control principle of electronic unit pump fuel system,speed control simulation model is constructed in Matlab/Simulink,including engine model,fuzzy adaptive PID controller model,etc.Research in starting condition and mutation load conditions has been done.The results show that fuzzy adaptive PID control has better control performance than conventional PID control and it is more suitable for dynamic regulating speed for diesel engine.Work discord in different cylinder of multi-cylinder diesel engine leads to fluctuating speed.Because electronic unit pump fuel system could control independently in different cylinder,cylinder balance control strategy is designed by diesel engine crankshaft transient speed.Signal characteristics of speed are extracted by Mallat analysis method of wavelet theory.Work uniformity degree index in different cylinder is put forward.Fuel injection quantity is compensated based on uniformity degree index to reduce combustion and work difference and uneven fluctuation of instantaneous speed.Control strategy validation test has been done on YC4E140-30 diesel engine test bench.The test results show that fuzzy adaptive PID control could meet speed regulation requirements and have good dynamic speed regulation.Uniformity degree index really reflects work deviation in different cylinders and cylinder balance control strategy has effect on developing uneven fluctuation of instantaneous speed which is caused by combustion and work difference.