With the progress of the times, the car has become an indispensable part of people's lives. However, the development of the automobile industry has brought enormous benefits to human beings, while it also consumes a lot of energy and pollutes our living environment. Therefore, this paper intends to use automobile exhaust heat combined with thermoelectric generator to recover part of the energy consumption of automobile. The energy can be converted into electric energy to supply the muffler with purification function, so as to achieve the purpose of energy saving and emission reduction. This paper summarizes the advantages and disadvantages of the first-generation exhaust gas temperature difference generator. In order to improve the power generation, the second-generation exhaust gas temperature difference generator is designed. The utility model has the characteristics of a hexahedron structure and is internally provided with a fin vortex structure. The utility model can increase the airflow disturbance, thereby improving the heat transfer efficiency and the generation power. In addition, using GT-POWER software, a small and medium sized vehicle engine is used as the research object. The simulation results show that the noise value of the engine is between 3500 and 6000r/min. Peak noise is in the 110-124dB interval, and the corresponding frequency of high noise values is in the 180-200HZ, which increases with the speed changes. The simulation results provide the basis for the design of the muffler. Based on the optimized design, the exhaust gas temperature difference generator is processed in real time. The experimental results show that the exhaust gas temperature difference generator designed in this paper has higher power generation efficiency, and it can meet the demand of power supply for the tail gas purification.