Controlling the temperature of the car catalyst is one of the effective factors in improving the efficiency of this part. The internal structure of the catalyst must be placed under certain thermal condition for optimally converting of exhaust gases. The theoretical and experimental results show that the internal structure of the catalyst in the temperature range of 300 °C to 600 °C has the greatest effect on greenhouse gases conversion. In this research, a theoretical solution has been proposed to prevent the deviation of the catalyst temperature from the defined limits. In order to prevent the raisin up the temperature of the catalyst, a double-walled converter with an asymmetric flow has been used. This part is installed before the car catalyst. The exhaust gases pass through it and then enter the catalyst. The cooler designed with four different lengths of 0.5 m, 1 m, 1.5 m and 2m. the performance of the design is investigated numerically using a commercial finite volume code. The state of heat transfer and its effect on the gaeses temperature reduction has been evaluated. According to the results, the 0.5 m in length cooler reduced the temperature to 291.6 °C. By selecting the temperature reducing converter and automatically activating the fluid circulation operation at the critical temperature, the performance of the electromechanical system derived from sensors and actuators have been investigated.