海拔高度对车用柴油发动机性能的影响

The influence of altitude on the performance of automotive diesel engines

基于高原模拟试验台架开展不同海拔高度下柴油发动机的性能排放试验。结果表明:随着海拔高度的增加,进气质量流量减少,空气中氧气含量减少,对高转速和低转速下的最大扭矩输出有较大影响,但在中间转速下其影响较小;随着海拔高度的增加,缸内燃烧效率下降,做功能力下降;随着海拔高度的增加,排气烟度增大,其中在低转速、大负荷下烟度对海拔高度更为敏感;海拔高度为1900m时NO_(x)排放体积分数与平原基本相当,当海拔高度增加到2400m时,NO_(x)排放体积分数显著高于平原下的情况。

Performance emission tests of diesel engines at different altitudes were conducted on a high-altitude simulation test bench.Results show that as the altitude increases,the intake mass flow rate decreases and the oxygen content in the air decreases,which has a significant impact on the maximum torque output at high and low speeds.However,its impact is relatively small at intermediate speeds.As the altitude increases,both the combustion efficiency in the cylinder and the power output decrease.As the altitude increases,the exhaust smoke intensity increases,with smoke being more sensitive to altitude at low speeds and high loads.When the altitude is 1900 m,the NO_(x) emission concentration is basically equivalent to that in the plain.When the altitude continues to increase to 2400 m,the NO_(x) emission con-centration is significantly higher than that in the plain.