The effects of the catalytic converter on two-stroke engine performance

摘要

The two-stroke engine, by its nature is very dependent on the unsteady gas dynamics within an exhaust system. This is demonstrated by the tuning effects on two-stroke engines, which have been well documented. In consideration of current emissions legislation, a two-stroke engine can be fitted w markets. The catalytic substrate represents a major obstruction to the flow of exhaust gas, which hinders the progression of the main exhausted pulse, and in turn effects the scavenging of the cylinder and ultimately the performance of the engine. Within this investigation, a 400 cc direct-injection, two-stroke engine was used with various catalysts positioned at different distances from the exhaust manifold. Comparison tests were performed between a fully lit off catalyst and a nonoperational bare substrate. This clearly demonstrates the detrimental effect of the hotter catalyst on the gas dynamics and hence engine performance and isolates these effects from the normal restriction caused by the catalyst. Effects on engine performance, cylinder trapping and burn rates were all analyzed and differences highlighted.