Investigation of the cooling and purification effect of automobile exhaust using heat pipe heat exchanger

Abstract

Heat pipe heat exchangers (HPHEs) have excellent heat transfer performance and have been applied in many fields. However, the cooling and purification effects of the HPHE on the automobile exhaust are still not clearly acknowledged. In this paper, an HPHE applied to automobile exhaust cooling and purification was designed and developed. By establishing 3D physical model and mathematical model, the influences of heat pipe inclination angles and cooling air temperatures on the cooling effect of the automobile exhaust are studied. And the cooling and purification effects under different engine speeds have been studied experimentally by connecting the HPHE to a 1.8 T Volkswagen Passat car. The results indicate that when the dip angle is 30°, the heat exchanger has the best cooling effect. When the engine speed reaches 3000 rpm, the heat removed by the cooling air reaches a peak of 3.06 kW with the maximum cooling efficiency of 56.37 %. The HPHE has a certain purification effect on the SO2 and NOx in the automobile exhaust. The maximum purification rates are 15.4 % and 13.8 %, and the peak purification rates appear at 2000 rpm and 2500 rpm, respectively, while the purification effect on the CO is not obvious.