Simulation of catalyst deterioration and the effect of misfire on the emission and engine performance of motorcycle engine

• Main Authors: Chang Tai Wu, 巫昶泰
• Other Authors: Jau Huai Lu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/30656869372672993312

碩士 === 國立中興大學 === 機械工程學系所 === 101 === A novel approach to simulate the catalyst deterioration and the effect of misfire on emission and engine performance are discussed in this paper. In the development of the OBD system of a vehicle, an aged catalyst is required to test the function of the system. This catalyst is partially deteriorated and the emission after this catalyst will exceed the regulation value with limited bound according to the testing protocol. This aged catalyst is very valuable, and difficult to prepare. A bypass in the exhaust pipe was used to simulate the deterioration of catalyst in this paper to investigate the emission characteristics of a motorcycle engine. This method of simulation has been conducted in a dynamometer testing and a chassis dynamometer testing. An electronic controlled motorcycle engine was used in these tests. Wind band oxygen sensors’ signals were used to calculate the catalyst deterioration index. The result shows that the degree of deterioration can be controlled by the portion of exhaust flow through the parallel pipe. A low dimensional catalyst model was built to confirm the practicability of the exhaust system made in this paper. A misfire generator based on single chip was developed in this paper to investigate the effect of misfire on the emission and engine performance of a single cylinder motorcycle engine. The results of the engine dynamometer tests show that the concentration of unburned hydrocarbons in the engine exhaust was raised and the engine torque declined as the misfire rate increased. 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.