Abstract: To reduce the emissions for gasoline engine during cold starting, the influences of crevice effect, wet wall effect because of the low cylinder temperature, adsorption/desorption of cylinder oil film and incomplete combustion on the HC emissions were analyzed. Moreover, the influences of the storage and release of oxygen on effective oxygen concentration were considered. The three-way catalytic (TWC) model was established with the lumped parameter method and analyzed under NEDC cycle. The temperature of exhaust gas getting in and out of the catalytic converter, the quantity and the efficiency curve of emissions were obtained. Furthermore, the conversion efficiency of HC and CO at oxygen flow rate of 0.2 g/s, 0.4 g/s, 0.6 g/s were analyzed respectively. The results show that the HC and CO conversion efficiency is improved nearly 20% under 0.6 g/s oxygen flow rate compared to 0.2 g/s oxygen flow rate. It proves that the accuracy and advancement of the model, and provides a theoretical basis for further optimization of the vehicle energy management control strategy.

Key words: cold starting, hybrid electric vehicle, TWC, modeling, simulation