Exhaust system for four-stroke combustion engine - has two pulsating exhaust gas flows supplied via a common exhaust manifold allowing exhaust gases to leave by a common pipe

摘要

In a four-stroke combustion engine exhaust system the engine operates at a pulsating working frequency driven by a number of cylinders each of which has an outlet to a manifold for the pulsating emission of exhaust gases. Two pulsating exhaust gas flows are passed through a catalyst matrix phase shifted against each other from one third to two thirds of the period of the working frequency. Each pulsating exhaust flow is supplied via a manifold merged from groups of two cylinders; and the resulting common exhaust manifolds conjoin the catalytic converter matrix from opposite ends. The treated exhaust gases leave the catalytic matrix by a common exhaust pipe. USE/ADVANTAGE - The arrangement improves the catalytic converter efficiency in cleaning exhaust gases from a four-stroke combustion engine by exploiting the dynamic characteristics of pulsating exhaust gases in driving the catalytic cleaning process. Further, the arrangement exploits the properties of metallic honeycomb catalytic substrate structures.