Development of the High Performance L4 Engine ULEV System

A new simple ULEV system has been developed, using only an underfloor catalytic converter. The new system features a VTEC (variable valve timing and lift mechanism) engine with a newly developed catalyst, a precise air-fuel ratio control for maximizing the catalyst performance and the newly developed low heat capacity exhaust system with the air-gap. These technology have contributed to a reduction in the feed gas, the quick activation of the catalyst and an improvement in the maximum conversion ratio of the catalyst, making it possible to pass the ULEV standard without sacrificing vehicle output power.