Aimed at the problems of smoke degree and temperature increasing brought by exhaust of smoke from the diesel generator groups in the automobile power unit, the project of controlling the system was designed by researching the optics and infrared control mechanism. The experiment proves that through the way of using rock wool to maintain the temperature, using the DPF and bag metal fibers to filter, and using the washing smoke system to lower temperature and to filter, could achieve good cleaning and cooling effect. Test results show that the exhaust backpressure is less than 14 kPa, the filtration efficiency is up to 99%, and the temperature range is more than 85%.