Emission Control on a Dual Model Hybrid Passenger Car to Meet China 6 Legislation

With the increasing number of hybrid vehicles in the Chinese market, research on aftertreatment systems for hybrid vehicles has become very popular. China has currently implemented national on-road China 6 regulations for emission control of all gasoline and diesel vehicles, including hybrid ones. So far, there are few papers on the optimization of aftertreatment for hybrid gasoline vehicles. Due to the introduction of electric motors in hybrid vehicles, the engine starts frequently and leads to inconsistent stability of engine operating conditions and brings the challenge to emission control of engine exhaust. This article selects a highly popular hybrid gasoline vehicle in China for research, which is a dual-mode hybrid (DM hybrid) passenger car. There is an obvious correlation between the emissions between the driving pattern and the hybrid strategy. The catalyst temperature is the main influencing factor on the performance of TWC catalysts, while the higher exhaust temperature brings the better conversion efficiency of pollutants. Since less thermal energy is needed to heat up the low mass substrate, the light-off performance of catalyst with same platinum group metals (PGM) loading is achieved earlier. As applied in the DM hybrid vehicle aftertreatment system, the low mass substrate can achieve 10~30% better performance in gaseous emissions reduction on China VI regulated cycle, Worldwide Harmonized Light Vehicles Test Cycle (WLTC), compared to the standard substrate both for fresh and aged catalyst samples. The catalyst coated on low mass substrate also enabled good Real Driving Emissions (RDE) result to meet China 6b.