Research On Electronic Fuel Injection Gasoline Engine Control Strategy Based On Two Stage Fuel Injection

Exhaust performance can be improved using EFI system. This paper had a refit of electrical fuel injection system to a motor cycle engine, In order to control the motor vehicles' exhaust emissions effectively, injection and ignition control strategy is studied in the paper and brought forward preliminary On-Board Diagnostic (OBD) methods of motor cycle electrical fuel injection system. The main research efforts and conclusions of this paper are as follows:1. We had a refit of electrical fuel injection system to the single-cylinder gasoline engines of Qingqi K157FMI. the carburetor was taken off from the fuel supply system and the new fuel supply system included air throttle body, fuel pump and fuel injector, and relevant sensors and electrical ignition control unit was installed in the control system. The paper introduced the selections of each sensor and the means of dealing with sensor signals, and detailedly introduced the composing, work principle and anti-jamming design of the control system linking the control unit.2. A control strategy of two-stage fuel injection was brought forward. Aimed at the different effect of two-stage fuel injection in the engine combustion, we had lots of experiments to study and analyze. In the idle work condition, the control strategy of alternately circles fuel injection was brought forward, assisted by adjusting ignition advance angle, we can effectively control the idle speed and reduce the oil consumption. In the steady work condition, the control system used proportion and integral (PI) control method to optimize the control of air-fuel ratio. The paper made a simple introduction of the PID controller principle, explained the process of using the method of extending critical proportions to set parameters, and made many experiments to validate the effect of the close-loop control. The results of the experiments indicated that the control system can accurately control the engine air-fuel ratio and effectively reduce the emissions by two stage fuel injection and PI close-loop control in the steady work condition.3. The preliminary On-Board Diagnostic (OBD) methods of engine electrical fuel injection system were brought forward. This paper made a research of On-Board Diagnostic methods about primary sensors of engine control system. The system compared the signals of sensors in normal state with failure state, and made marks to the signals of disabled sensors in the system, jumped over the relevant signals to control the engine, made the engine run normally, and remind the user to examine and repair the sensor.