水平对置活塞发动机高空热平衡特性研究

目的研究不同海拔大气压力特别是高空条件对水平对置活塞汽油机热平衡性能的影响。方法利用内燃机高空模拟试验台进行不同海拔高度(0~7000 m)下水平对置活塞汽油机的热平衡试验,测得不同海拔下排温、缸体表面温度等特征参数,计算热流量分配特性,并对比分析热流量分配特性随海拔高度的变化规律。结果随海拔升高,汽油机排温和缸体表面温度逐渐下降,且海拔愈高,缸体表面温度下降幅度愈大。汽油机有效功率随海拔升高逐渐下降,余项损失百分比逐渐上升,且在低转速下,变化幅度增大。在6000 m模拟海拔、3000 r/min转速下,汽油机有效热效率不到5%,而余项损失达到了30%以上,此时部分汽油甚至并未燃烧。结论高空环境对水平对置汽油机热平衡性能造成严重影响,成为制约其高海拔性能恢复的关键因素。

High-altitude Thermal Balance Characteristics of the Boxer Piston Engine

Objective To study on effects of atmospheric pressure at different altitude, especially effects of high-altitude conditions on thermal balance performance of boxer engine.Methods The thermal balance test of the boxer engine at different altitude (0-7000m) was carried out on a high altitude simulation test platform for the internal combustion engine. The characte-ristic parameters such as exhaust temperature and cylinder surface temperature were measured. The heat flux distribution cha-racteristics were calculated. And the variation law of heat flux distribution with altitude was compared and analyzed.Results With the increase of altitude, both the exhaust temperature and the cylinder surface temperature of the gasoline engine gradually decreased. The higher the altitude was; the greater the drop in the cylinder surface temperature was. The effective power of the gasoline engine gradually decreased with the increasing altitude. The percentage of the residual loss gradually increased. The variation range increased at low speed. At the simulated altitude of 6000m and at 3000r/min, the effective thermal efficiency of the gasoline engine was less than 5%, while the percentage of residual loss reached more than 30%. Part of the gasoline didn't even burn at this time.Conclusion The high altitude environment has a serious influence on the thermal balance performance of the boxer engine, which is one of the key factors to restrict the recovery of its high altitude performance.