Gitano, H., Chim, R., and Loh, J., "The Application of a Resistive Type O2 Sensor to a Small Engine EFI System," SAE Technical Paper 2014-32-0073, 2014, doi:10.4271/2014-32-0073.
Recent concern over air quality has lead to increasingly stringent emissions regulations on ever smaller displacement engines, resulting in the application of Electronic Fuel Injection (EFI) to the 100cc-200cc class 2-wheelers in many countries. In the pursuit of ever smaller and less expensive EFI systems a number of unique technologies are being explored, including resistive type oxygen sensors. In this paper we investigate the application of a prototype resistive oxygen sensor to a small motorcycle EFI system. Measurements of the exhaust system temperatures, and Air/Fuel Ratio (AFR) and resistive sensor response are carried out, and compared to the standard zirconia oxygen sensor to create an estimate of the sensor's in-use performance. Motorcycle performance data are compared using both a standard zirconia switching type oxygen sensor, and the new resistive type oxygen sensor to control the air/fuel ratio. Results indicate that the resistive type oxygen sensor is capable of allowing the EFI controller to successfully control the vehicle's AFR in all operating modes with a significantly faster “light off” time, and lower overall current draw when compared to the standard heated zirconia sensor.