A Study of Heated vs. Unheated Oxygen Sensor Applied on a Motorcycle EFI System

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.