Simulation Analysis of Environmental Adaptability of High Pressure Fuel Cell Engine Air Supply System

High pressure fuel cell engine, namely high pressure fuel cell system for automobiles, is the core power plant of fuel cell vehicle. Among many categories of fuel cells, proton exchange membrane fuel cell (PEMFC) is the most widely used one for automotive applications, with the characteristic of high power density, fast response and moderate working conditions. The cathode oxygen supply in PEMFC is one of the most important factors which affects its output power and operational lifespan. Reasonable regulation of air supply process flow and pressure can effectively improve system’s performance and efficiency. In this paper, a mathematical model of the air supply system and a model of altitude and environmental pressure are established in MATLAB \ Simulink by mechanism modeling method. Then the modules of the air supply system are integrated to supply air to the 85 KW PEMFC stack model. According to the nonlinear optimal theory, the optimal steady-state condition of the system under different net power is found. Simulate the air supply system under different altitude from 0 m to 4000 m. With analyzing the simulation results, it can be concluded that high-voltage fuel cell engine maximum output net power will be reduced by about 6% with each 1000 meters rise of altitude in the condition of the altitude below 3000 meters. From 3000 to 4000 meters, it will be reduced by 11%. At the same time for high-pressure fuel cell engine in high altitude environment, to ensure that it has the same net output power and the best efficiency as low altitude areas, the speed, the opening of back pressure valve and current must be increased as appropriate.