LPG 엔진 촉매변환기 내 2차 공기 분사 시스템 운전 범위에 관한 연구

Emission analysis during cold start period of CVS-75 mode in LPG vehicle was performed to find out proper operating conditions of SAI(Secondary Air Injection) system. To do this, using commercial 1-D code AMESIM, the full exhaust system with SAI as well as MCC(Manifold Catalytic Converter) and UCC(Under body Catalytic Converter) was modeled. And the effects of SAI air flow rate, supply time on HC, CO and NOx emission was analyzed with the simulation model with 7 step global surface chemical reactions of Langmuir-Hinshelwood type. Through the simulated results, we find that 29% HC reduction and 50% CO reduction can be achieved with SAI under the optimal operation value, 1.6g/sec air for 30sec.