气动发动机排气冷量在内燃机冷却系统中的回收利用研究

针对气动发动机排气的低温特性，提出了利用气动发动机排气冷却内燃机散热器的技术方案。通过初步试验，获得了气动发动机在不同转速下的排气流量和温度特性。基于初步试验结果，建立了气动发动机排气与内燃机冷却水的热交换模型，并进行了仿真计算，得到了不同水泵流量下，热水流经换热器的进出口温差以及换热量。研究结果表明，换热器进出口热水温差、换热量随着气动发动机转速的升高而增大；随水泵流量的增加，热水流经换热器进出口的温差逐渐减小，换热量增大，但各个水泵流量下的换热量相差较小，当发动机转速为700r／min时，温差增加值及换热量的增加值均为最小；随着气动发动机转速增加，气动发动机排气的冷量炯变化范围很小，回收指数逐渐上升，冷量回收效果变好。

Recycling of exhaust cooling capacity of pneumatic engine in cooling system of internal combustion engine

Aiming at making full use of the low-temperature characteristics of pneumatic engine, the technical scheme of applying exhaust from pneumatic engine as cooling media to cool down engine radiator was proposed. Exhaust flow and temperature characteristics of pneumatic engine at different speeds was provided by preliminary experiments. The heat exchange model of pneumatic engine exhaust and cooling system of internal combustion engine was established based on preliminary results, and simulation calculations were conducted. Under different pump flow, the heat transfer capacity and the temperature difference between inlet and outlet when water flows through the radiator were ob- tained. The results show that, temperature drop and heat transfer increased as the speed of pneumatic engine raised. As pump flow in- creased, temperature difference reduced, heat transfer enhanced with small increase rate, the increment of temperature difference and heat transfer are the minimum at engine speed of 700 r/min. With the pneumatic engine speed increased, the range of exhaust cool exergy is small and recovery index gradually increased which means recycling effect of cooling capacity turned better.