GB/T 20969.4-2008

This standard provides guidelines for conducting natural environment tests on internal combustion engines intended for use on plateaus, specifying test methods, procedures, and evaluation criteria. It is applied in the design, manufacturing, and quality verification of machinery such as construction equipment, vehicles, and power generators operating at high altitudes. The standard ensures engine performance, reliability, and adaptability under low-pressure, low-oxygen, and cold plateau conditions.