The Effect of Misfire on the Emission and Engine Performance of a Single Cylinder Motorcycle Engine

Abstract

A misfire controller developed by the authors was used in this paper to investigate the effect of misfire on the emission and engine performance of a single cylinder motorcycle engine. Three kinds of test were carried out, the idle test, the engine dynamometer tests, and the chassis test. It was found that in the engine dynamometer tests, the concentration of unburned hydrocarbons in the engine exhaust was raised and the engine torque declined as the misfire rate increased. The variations of the CO and CO2 are not the same in different operating conditions. At low load, CO concentration increased with the misfire rate while CO2 moved in an opposite direction. Contrary condition happened at high load. The CO2 concentration increased with the misfire rate while CO varied in the opposite way. Results of idle test showed that misfire would cause moderate deterioration of engine emission. However, chassis dynamometer test showed that even 1% of misfire would cause severe increase of emission.