Research on Diagnostics Methods of CNG Engine After Treatment Catalyst

摘要

In this paper, a dynamic oxygen storage model of three way catalyst (TWC) for diagnose was established. The high-efficiency conversion region of the catalyst under steady and dynamic conditions were analyzed through engine bench test. Under steady conditions, the high-efficiency conversion region of three kinds of pollutants is 0.990-1.005, and the high-efficiency conversion region is 0.996-1.004 under transient conditions. Combined with the diagnostic requirements, a method for calculating oxygen storage in the test cycle was proposed. Through the test of the natural gas engine, the fresh catalyst and the 30 h high temperature aging catalyst are tested. Through the calculation formula of the circulation oxygen storage, the oxygen storage of the aging catalyst is reduced by 36.88%. The diagnosis method can effectively judge the deterioration degree of the carrier.