The Development And Research Of Electronic Fuel Inject System For ATV Engine

ATV is called All Terrain Vehicle or sand beach automobile; it exerts quite important effect in recreation, agriculture, national defence and fire protection field and so on. The export quantity of ATV of China's motorcycle enterprises increase year by year, becoming a major corporate profit growth, but Almost all large displacement ATV for the carburetor fuel supply method, are hard to achieve the American and European's strict emissions regulations for ATV. The engine using Electronic Fuel Injection Technology (EFI) can improve the power, the economy and reduce pollution emissions; EFI becomes an important direction of technical development for Domestic motorcycle enterprises.In order to reach CARB (California Air Resources Board) emission standard of California, reference to the electronic motorcycle technical characteristics from home and abroad. Engine EFI system is studied in-depth and detailed in this thesis; take the gasoline engine that was used for 400ml ATV as a prototype, an electronic fuel injection system for ATV engine is designed.According to the engine characteristics and requirements of the industry, system uses speed - density of the intake air technology ,and intake manifold fuel injection., design and transform the fuel supply system ,the intake system and the ignition system, ECU makes acquisition of sensor signals(such as intake air pressure -temperature sensor, Crankshaft position sensor and so on), the Electronic Control System can confirm the operating state of the engine, then it controls fuel pulse width and ignition advance angle which can be got from the MAP stored in the memory of ECU. In order to improve the efficiency of TWC (Three-Way Catalytic Converter), a closed-loop control arithmetic is applied in this thesis, and it is proved during tests that it can keep air-fuel ratio around stoichiometric values.The design of Electronic Control System includes hardware design, software design and anti-interference design. In this thesis the hardware circuits are composed of the main circuit chips, power supply circuit, and input signal processing circuit and output signal driving circuit. The main program of the software system includes starting module, idle module, accelerating module, decelerating module, steady state module and overspeed cut off module. Interrupt procedures includes TPM module and signals acquisition module..In order to carry out the calibration of various control parameters, establish a system of engine test bench. Bench system uses AVL PUMA Open Engine Dynamic Test System, using VB6.0 develop a PC calibration software, it acquires the state data of engine and optimize the controlled parameters and MAP. Engine performance tests show that the EFI System improves ATV engine power, economyand meets CARB emission regulations, and is suitable for industrial demand.