The working process model and cooling system model for diesel engine were established and directly coupled with GTsuite software. The effectiveness of model was verified by the plateau simulation bench test, and then the variation laws of diesel engine and its cooling system performance under external characteristic working conditions at different altitudes were studied. The results show that the water temperature at the outlet and the fuel consumption rate increases by 5.01% and 4.67% on average and the heat dissipation, the fan mass flow and the engine power decreases by 6.25%, 11.20% and 3.55% on average for each 1 000 m elevation of altitude. The armored vehicle cannot work unless the load decreases or the cooling capacity of cooling system increases at low speed between 1 000 m and 2 600 m and the whole speed range above 2 600 m. Finally, the MAP of engine maximum allowable load and fan minimum volume flow rate increase are calculated and determined based on the alarm limit of outlet water temperature, which provides a reference for the matching and optimization of diesel engine and cooling system in the plateau environment.
