1-D transient emission analysis of LPG engine catalytic converter with secondary air injection during cold start period of CVS-75 mode

초록

A 1-D transient emission analysis was performed during the cold start period of the city driving 75 (CVS-75) mode for a liquefied petroleum gas (LPG) vehicle to identify the optimal operating conditions of a secondary air injection (SAI) system. A commercial 1-D program, AMESim, was used to model the full exhaust system, including the SAI system, as well as a manifold catalytic converter (MCC) and an under-body catalytic converter (UCC). Next, the effects of the SAI air flow rate and the supply time on HC, CO, and NO (x) emissions were analyzed using the simulation model with 7-step global surface chemical reactions of the Langmuir-Hinshelwood type. From the simulated results, we found that a 29% HC reduction and a 50% CO reduction can be achieved with the SAI system under the optimal operation conditions of 1.6 g/s of air flow rate for 30 s.

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