Exhaust Manifold Design for Reducing Converter-In HC Emissions and Improving Catalyst Light-Off Via Secondary Air Injection

摘要

The effect of exhaust manifold design was examined in this study to enhance catalyst light-off performance and remove HC emissions entering the catalytic converter before the catalyst is lit off when secondary air injection approach is applied during cold start. The effects of several design and operating parameters such as secondary air injection location, spark timing, engine enrichment level, and secondary air flow rate were also carefully studied in order to maximize the system benefit. Proper design of the exhaust manifold was found crucial in the success of the secondary air injection strategy to minimize HC breakthrough and shorten catalyst light-off time during cold start.