Abstract
Recently, concerns about environmental conservation have been growing, and reducing the exhaust emission and enhancing the fuel economy are being major subjects for small motorcycles. Therefore, electronic control fuel injection systems, which can finely control an air-fuel ratio, have been employing. This time, the ECU integrated throttle body system for the electronic control fuel injection system, which is compact and low-cost, for a small displacement engine was developed. Features of this system are to combine two modules. The modules are throttle body module with several bore sizes in series and ECU module with electronic control unit, sensors, and idling-air-control device. As a result, the complex wiring and piping were minimized, the miniaturization was achieved, and the system with generality that enables to install to the single cylinder engine from 50cm3 to 250cm3 was achieved.