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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。
Aim To study the effect of atmospheric pressure at different altitudes, especially at high altitudes, on the thermal equilibrium performance of a horizontal opposed piston gasoline engine. Methods The heat balance test of horizontally opposed piston gasoline engine at different altitudes (0 ~ 7000 m) was carried out by using the simulation platform of internal combustion engine at high altitudes. The characteristic parameters of exhaust temperature and cylinder surface temperature at different altitudes were measured to calculate the heat flux distribution characteristics. Comparative analysis of heat flux distribution characteristics with altitude variation. Results As the altitude increases, the exhaust temperature of the gasoline engine and the cylinder surface temperature gradually decrease, and the higher the altitude, the greater the temperature drop of the cylinder surface. The effective power of gasoline engine gradually decreases with the altitude increase, the percentage of the remaining losses gradually increases, and at low speed, the change range increases. At a simulated altitude of 6,000 m, the effective thermal efficiency of the gasoline engine is less than 5% at an RPM of 3000 r / min, while the remaining losses reach more than 30%, at which time some of the gasoline does not even burn. Conclusion The high altitude environment has a serious impact on the thermal balance performance of the horizontal gas engine, which becomes a key factor to restrain its high altitude performance recovery.