1-D TRANSIENT EMISSION ANALYSIS OF LPG ENGINE CATALYTIC CONVERTER WITH SECONDARY AIR INJECTION DURING COLD START PERIOD OF CVS-75 MODE |
J. E. YUN |
Kangwon National University |
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ABSTRACT |
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 NOx 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. |
Key Words:
Catalyst, Conversion performance, Cold start emission, LPG, Secondary air injection |
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