Membrane gas separation behavior of engine intake system with variable gas composition

A new membrane device for gas separation was developed and tested on an engine. The tests were done in the pressure operation mode and vacuum operation mode respectively to investigate the flow characteristics of both streams of oxygen-enriched air(OEA) and nitrogen-enriched air(NEA), as well as the performance of gas separation process. The results showed that in the pressure operation mode, the composition concentrations of both streams are in inverse proportion to mass flow rate, which is in favor of the preparation and regulation of NEA stream. In the vacuum operation mode, the concentration of OEA stream is in direct proportion to mass flow rate, which is in favor of the preparation and regulation of OEA stream. It was found that the air supply pressure, the suction vacuum and the pressure difference between both sides of the membrane are the decisive factors for gas separation, and the temperature is also significant. Therefore, it is necessary to incorporate all factors, coordinate the flow rate and gas concentration to meet the requirements of engine intake process.