Abstract
To aim at the exhaust emission reduction and the fuel economy improvement, and to improve the engine start ability, the practical use of the fuel injection system for small motorcycles has been demanded. Issues in practical use of the fuel injection system in small motorcycles are to achieve the system configuration that improves the arrangement flexibility of the system along with performing significant downsizing and simplifying of components compared with them of passenger cars. For the injector, magnetic circuit was optimized through computer simulation and pressure losses in fuel passage are reduced. The fuel pump motor is down-sized with the pressure regulator uses a ball and a spring type contraction. The fuel pomp module reduces the size of fuel pump mounting surface, allowing a modification from the flat-surface sealing to the radial sealing and the pump mount method is changed from the bolt-on to the retainer-slide type. Furthermore a custom IC was used for the ECU and the housing was standardized. The small diameter resin fuel foes made it possible to arrange tubing without molding along with shape of frame.
Keywords: Fuel injection, Emission, Fuel consumption, Fuel Pump, SI engine