Search Results

In the future more stringent emission regulations will enforce closed loop control of engine management systems for a large number of inexpensive low displacement motorcycles in markets like China and other Asian countries. Specific low cost Electronic Fuel Injection (EFI) systems have been developed or are under development to meet these requirements. This study presents a comparison of heated vs. unheated oxygen sensors in such a system. The exhaust gas temperature rise and variation during the emission test cycle in this class of motorcycles and its impact on the light-off time, the dynamic response behavior as well as other small engine specific parameters are investigated. Most experiments have been carried out on a 125cc motorcycle equipped with water cooled 4 stroke engine with 3 way catalyst.

In electric fuel injection (EFI) systems the intake air pressure is used as system load signal for calculating injection and ignition parameters together with engine speed. Part of an EFI system for motorcycles is a throttle body module with integrated pressure sensor. As motorcycle systems require smaller components than automotive applications the target for engineering is to minimize the component size and still fulfill other system requirements. Therefore the pressure sensor sampling point should be as close as possible to the throttle shaft to reduce the module size but with a sufficient distance to avoid signal distortion by unsteady flow. This paper describes how to find a suitable sampling position by combining static bench testing, dynamic vehicle testing and CFD analysis.