Research On The Characteristic Of Intake Air For FAI EFI Motorcycle Engine

Increasingly stringent regulations on motorcycle pollutant emissions have forced Chinese motorcycle manufacturers to adopt the Electronic Fuel Injection (EFI) System for motorcycles, following the same path the automotive industry has done. However, current motorcycle EFI system is much less advanced than its automotive equivalent. The most important problem is the air-fuel ratio control during the transient operation. Therefore, more fundamental studies are required to improve its performance and efficiency.The key problem of the air-fuel ratio control during the transient operation is the actual intake air mass when the throttle suddenly moves after sampling of the intake air mass. The object of this research is CG125 EFI motorcycle, and a model of this engine is established to simulate its characteristic of intake air. Using this model can calculate the actual intake air mass during the transient operation, and then give some advice for making the EFI control strategy.At first, the basic characteristic of the intake air for motorcycle engine is found through some experimental study, which is distinct different from the automotive engine. The wave action simulation of the inlet and exhaust manifold for internal combustion engines have been developed for many years, and several solution methods of this problem are researched. Finally, a CG125 engine model is set up by using the GT-Power which is powerful engine simulation software. This model can exactly simulate the every parameter of the steady operation, and then it is used to calculate the actual intake air mass during the transient operation and some extreme operation conditions. The output of simulation is according with the theory analysis, and can be used for making the EFI control strategy.