Performance enhancement of the gasoline engine hydrocarbon catchers for reducing hydrocarbon emission during the cold-start period

Abstract

Hydrocarbon(HC) emission from cold start for gasoline engine has become a big problem as the emission regulations go increasingly stringent. Zeolites are used to reduce hydrocarbon emission from gasoline engine before three-way catalysts reaching its operating temperature. In this paper, a mathematical model is fitted from hydrocarbons emission experimental data and a computational fluid dynamic(CFD) method is applied to investigate the influence on adsorption capacity of the different gasoline engine hydrocarbons catchers, and grey relational analysis is used to analyze and enhance adsorption performance of the gasoline engine hydrocarbon catchers for reducing hydrocarbons emission during the cold-start period. Driving cycle Federal Test Procedure(FTP) 75 is adopted to see the transient response of adsorbing hydrocarbon in cold start period. Results show that both hydrocarbon catcher length and its zeolite type in gasoline engine have great impact on hydrocarbon adsorption, the ranking of adsorption capacity is 25 cm > 20 cm > 15 cm, 5A > 13X. The gasoline engine hydrocarbon catcher with 25 cm length using zeolite 5A is of the best adsorption performance, and with this hydrocarbon catcher, the adsorption efficiency is 35.8% under cold start for driving cycle FTP75.