Effect of Operating Condition Change on the Conversion Efficiency of TWC with HCNG Engine

Abstract - Stoichiometric combustion engine with Three-way catalyst had an advantage that can reduce the harmful emissions effectively. Fuel equivalence ratio controlled from engine is very important because Fuel equivalence ratio with high conversion efficiency was narrow. This study analyzed the conversion efficiency under whole range of operating area for to evaluate the performance of three-way catalyst. In order to identify the Optimum conversion efficiency, the conversion efficiency due to change the control value of fuel equiv-alence ratio was investigated. The result show that conversion efficiency of emissions(more than 95%) has dis-covered by means of fuel equivalence ratio control at each test condition. As engine power increases, optimal fuel equivalence ratio tended to increase linearly under operating conditions of similar exhaust gas temperature. Key words : HCNG(Hydrogen- Compressed Natural gas Blends), stoichiometri c, TWC(Three-way Catalyst), conversion efficiency, equivalence ratio