Development And Research On Electronic-controlled Fuel Injection System Of Motorboat Gasoline Engine

The motorboat is a kind of small high-speed power boats. In the 1960s, it began to be developed. Making use of its high speed and high mobility, motorboat is used to patrol, search, rescue and sports compete in rivers, streams, lake and coastline, simultaneously. At present the market mainly concentrates in developed countries such as the European and American. It has become a kind of mainstream of entertainment products in the developed countries. Market prospects of the motorboat are broad.According to the requirement of the project, with the characteristics of motorboat, an electronic controlled gasoline mufti-point injection system developed for gasoline engine used in motorboat. Selected the injector, did the experimentation about the injector flow characteristics and measured the curve of the injector flow characteristics.The system is composed of air system, fuel system and control system. Taking a series of controlled parameters as the inputs through some sensors, such as MAP(Manifold Absolute Pressure sensor), CPS(Crankshaft Position Sensor), MAT(Manifold Air Temperature sensor), CTS(Coolant Temperature Sensor) and TPS(Throttle Position Sensor), the system controls the air-fuel ratio and ignition advance according to the controlled parameter maps stored in the memory of ECU. During the control process, the system adopts the proper control strategy in accordance with the operating mode as start, idle, acceleration, deceleration, and cruising mode in which the engine is working, and therefore the different needs for air-fuel ratio and ignition advance in various operating modes can be met. The air-fuel ratio and the ignition angle of advance of this system adopt the open-loop control. It can respond quickly to meet the requirements of motorboat; the idling system adopts the closed-loop control. It can meet the motorboat engine speed stability and emissions requirements.In the thesis, the system takes MC9S12DG128 singlechip as processor of the control unit. The ECU design mainly includes the hardware design and the software design. The hardware circuit mainly includes the input signal processing electric circuit, the output signal processing electric circuit and the communication circuit. The contents of ECU software design include: establishing mainly control program in accord with the control model, serial communications, and other routines. The mainly control program is made up of the main program and many programs of service interruption and processing subroutine, it completed the data collection, processing, export control, and other major features.This thesis introduced the process of stable state operating mode control parameter calibration for electrically controlled system of gasoline engine used in motorboat, as well as the transition operating mode control strategy, has realized the engine on engine dynamometer steady running through the experiment.