基于满足国Ⅵ b排放标准的重型天然气发动机，在潍坊地区和昆明地区进行了发动机台架WHTC循环排放测试，研究天然气发动机在高海拔地区的性能表现。研究发现：天然气发动机在昆明地区运行时， WHTC循环功降低，扭矩响应回归性较差，过量空气系数较小且波动较大，排气温度较高，EGR率设定值大于实际值。在两种不同海拔地区运行时，发动机污染物排放均满足国Ⅵ排放限值，相较于潍坊地区，昆明地区NO_x的排放低22.6%，THC排放高53.2%，CO排放高32.3%。研究表明，发动机在开发标定过程中需要兼顾不同海拔环境，为排放留出更宽裕度。

Based on the heavy-duty natural gas engine which met China Ⅵ b emission standards, the WHTC cycle emission test was carried out on the engine bench in Weifang and Kunming to study the performance of natural gas engine in high-altitude area. It was found that the WHTC cycle work of engine reduced, the torque response regression became poor, the excess air coefficient was small and fluctuated greatly, the exhaust temperature was high, and the EGR rate was set more than the actual value in Kunming. When operating at two different altitudes, the natural gas engine met China Ⅵ emission limits for all pollutants. Compared to Weifang, Kunming showed 22.6% lower NO_x emission, 53.2% higher THC emission, and 32.3% higher CO emission. The study indicates that engine development and calibration must account for varying altitude environments, allowing for greater emission margin.