A Study On Powertrain Matching Of LDT Under The Constraint Of Exhaust Emission

With the rapid development of city construction, the number of motor vehicles has a great increase. It shows that the number of motor vehicles in China increase fifteen percent each year in recent years. This not only makes China become an oil-imported country, but also makes the environment in the city become worse and worse. In some areas, the environment was badly polluted.Nowadays, vehicle fuel consumption and emissions has become a serious society problem. In order to relieve the controversial issue of rapid oil consumption and shorted oil provision, it is necessary to hold the emission properties as an integrated factor to evaluate the automobile performances and do some further research, especially, for the traditional fuel consumption automobile which is a main product in vehicle market.This paper is designed to do some research relate to emission property of BJ1027 on the basis of ADVISOR. The paper use ADVISOR to establish mathematical and control models of each part of powertrain. The models use the velocity and toque at wheels as a negative feedback information to vehicle control part, while use the achieved speed and toque of Engine as a positive feedback to the vehicle control part. The models are proved feasible through comparisons to the experimental results.In order to evaluate three different powertrain matching in BJ1027, the paper simulates the influence of different final drive ratios to the emission property. Results show that fuel consumption per 100 kilometers is increasing with an increasing final drive ratio, the emission of CO is decreasing when the final drive ratio is decreasing while the HC emission is decreasing with the increasing final drive ratio. But emissions of CO and HC have a little change with the final drive ratio. The NOx emission has a complicated varying law with the final drive ratio. First, the NOx emission decreases to a minimum value when the final drive ratio decreases, then it increases with the decreasing final drive ratio.Furthermore, different gear also has a great influence on emission property. Simulation results show that harmful emission centralize in low gear areas and it stays at a low and stable level in the high gear areas. Whether the fuel consumption rate or harmful emissions has peak value during the acceleration courses when the gearbox shift to another gear.The research in the paper makes sense during the courses of optimization design, it is really a try to find the relationship between influence factors and emission properties. This will spur the designers to consider dynamical and emission properties in the design stage which can shorten the design cycle.Besides, the research on factors that influence emission can urge the manufacturers to produce more clean fuel consumption automobiles.