Development Of Fuel System Test Platform For GDI Gasoline Engine

GDI gasoline engines are currently drawing more concerns of this industry due to their advantages of perfect cold start performance and high heat efficiency. As core components in the fuel system of the GDI gasoline engine, the pump-rail-injector and the fuel injection control technology are critical. The research done to the pump-rail-nozzle system can promote the localization of the fuel system of GDI gasoline engines. In order to do researches on the fuel system of the gasoline engine, a test platform is developed. The self-designed control and drive module is used, achieving the control of fuel pumping and fuel injection. On the test bench of injection quantity, each fuel injection quantity of the injector is measured. In addition, the test platform can be used to calibrate the data for the fuel system of the GDI gasoline, providing data support for companies that manufacture high pressure fuel pumps and injectors. On the test bench, the rail pressure and other parameters are measured, providing boundary conditions for the simulation analysis of the fuel system of the GDI gasoline engine and also building a test basis for researches on the rail pressure control strategy.The research has insights on the development of the test platform for the fuel system of the gasoline GDI engine and has finished these works:The research designed and established the test bench for the fuel system, selected a variable frequency motor to drive the high pressure fuel pump, arranged the 120-4 tooth disc and the 4+4 phasing disc for the future CPU hardware-in-loop simulation of the gasoline GDI engine, reconstructed the existing fixtures of the fuel pump to fix it, designed the collector for the fuel, designed and established the test bench for injection measurement basing on the displacement formulation, designed the pintle injectors which can be used to measure the fuel injection quantity by displacement sensor.The research developed the single chip microcomputer system with the chip of MC9S12XEP100, completed the acquisition of rail pressure signal、 displacement signal and frequency signal, developed the drive module for solenoid valves, designed the voltage booster circuit and the switched freewheeling circuit, achieved the control of the solenoid valves by 3-sectional current, designed the current measuring circuit to monitor the operational states of solenoid valves.The research also developed the bottom code of the drive module for fuel system, completed the acquisition of analog signals and frequency signal, injectors and the drive control of injectors, high pressure pumps and drainage solenoid valves, developed the rail pressure control strategy by incremental PID.With the data acquisition card, the acquisition monitor system has been developed for of the test platform.The test and validation has been carried out on the test platform. The results showed that the drive control module which had been satisfied the test requirement could adjust the rail pressure and control the injectors injecting according to the predetermined values.Using the injection quality measured by the measuring cylinder as the basis reference, it explored the causes leading to the measurement deviation and proposed the improvement plan.