Research On Low Emissions Technologies For Automotive Gasoline Engines

Beijing will enforce the Euro III standard for controlling vehicle emissions since 2008. This is a challenge to the present technology of vehicles. Besides the reconstruction to the existing vehicle technology, we must employ other kinds of technologies to meet the EuroIII standard.In this thesis several novel technical methods were discussed and it was also pointed out that the key technology to meet the EuroIII standard is to control the engine emissions during cold-start. According to the data of emissions acquired during cold start and running of engine under different conditions and surroundings, investigations were made in the following aspects: the influences of the engine structure (intake manifolds structure and crevices in cylinder) on the emissions; the relations between lean-burn and emissions; the optimal spark timing during cold start and the special catalysis during cold start.In the experiments, the main method we employed was antitheses: the comparison of emissions under the same conditions with different surroundings; the contrast of emissions of different engine structures under the same conditions and surroundings; the differences of emissions with different controllable parameters. Finally we found out the optimal parameters of engine emissions control under different conditions and surroundings and the trend of controlling emission.Based on the further analysis, the following results were obtained: the rule of optimal spark timing during cold start; the relationship between engine crevice and HC emissions; the corresponding appropriate structure of intake-pipe during different stages, etc. Some results are new findings by writer and innovations. We also validated the effects of catalysis during cold start and lean burning on emissions, etc. By combining the theoretical study and experimental investigation, We put forward the improvement method for electronic engine technologies which can reduce emissions greatly. All these will have significant meaning for further theoretical study. By the way, our experiments were carried out in Beijing's special environments and the electronic engine control system we utilized belonged to "ChiYung Co; Ltd" (our co-work company). So the conclusions this thesis presented will be used for their benefit in the end. From this point of view, this paper also has the great practical value.