Research On The Control System Of 50cc FAI Two-Stroke DISI Engine

Two-stroke engine has its intrinsic advantages in terms of high specific power, compactness, light weight, low cost, etc. However, two-stroke engine is reaching an important appointment for its survival due to its high emission level and poor fuel economy. Theoretically, GDI(Gasoline Direct Injection) is an effective way to solve the short-circuiting problem, since it allows the introduction of the fuel separately from the scavenging air.A simple, reliable and cost effective FAI system is applied to a 50cc two-stroke engine in this dissertation. The combustion system for DISI is developed; A great number of dynamometer experiments are carried out to investigate the effects of fuel injection phasing on the performance, emission, fuel consumption of the engine during idle,light load and middle load operating conditions. The torque performance, fuel consumption and emission economy of the engine is tested and compared with those of the original carbureted engine.Results of dynamometer tests demonstrate that, the FAI DISI can effectively reduce the HC emission and the fuel consumption in all operations.In a conclusion, the FAI system can completely remove the fuel short-circuiting, and greatly improve the performance during heavy load operating conditions. During light load operations, the fuel consumption and HC emission are reduced by adopting charge stratification. The FAI Tow-Stroke DISI with its EMS successfully improve fuel economy while reducing HC emissions largely at the same time.