Research On Control Strategy Of Fuel Injection System For GDI Gasoline Engine

Facing the increasingly serious energy crisis and stringent emission regulations,GDI engine came into being,it has great difference with the traditional PFI engine in the whole structure,and a huge advantage in reducing fuel consumption and reduce emissions.In this paper,research on a 1.5T GDI gasoline engine,a detailed analysis of the structure and working principle of each part of the electronic control system of GDI engine used in this experiment,on the basis of the following work:(1)Starting from the gasoline engine,understand the signal control,summarized to find the sensor corresponding to the signal type analysis,drive logic,input and output.At the same time,according to the electrical characteristics of the sensors and actuators,the drive circuit and signal conditioning circuit are designed.(2)According to the characteristics of high pressure oil pump,the control method of fuel rail pressure is determined.According to the phase relation between the camshaft and the crankshaft signal,the output signal is supplied at the right time.The fuel rail pressure control logic is designed,and the rail pressure control is divided into two stages:the starting stage is controlled by MAP,and the control method is based on the combination of PID control.The fuel rail pressure control experiment is carried out on the fuel system test bench.(3)According to the characteristics of the engine under different working conditions,analyzed the control factors of gasoline engine air fuel mixture control and ignition system,establishes the corresponding working conditions of fuel injection strategy,including the starting condition,warm conditions,idle speed,part load,large load,and deceleration and oil cut-off conditions.(4)Discusses the injection time and single injection under the influence of injection timing under the two injection and two injection ratio on the emission characteristics of a direct injection gasoline engine,the results in table two that appropriate injection parameters compared to the single fuel injection strategy of unburned HC emissions are significantly reduced.