Comparative study on air distribution system for piston-type compressed air engine

The open and close duration, angle, and pressure of the intake and exhaust valves substantially influence compressed air engine efficiency and output power. In the actual prototype, the air distribution system can be of two types, cam air distribution type and rotary air distribution type. Compressed air engine based on the two types has been investigated. However, there have been debates over the advantages and disadvantages of these two technologies. The article aims to compare two technologies from the output power and energy efficiency. To verify theoretical analyses’ model, an experimental system is built to test the output power and efficiency of compressed air engine with cam air distribution system. It is shown that the output power of the compressed air engine with rotary air distribution system is higher than that of the compressed air engine with cam air distribution system. When the rotation speed is equal to 800 r/min, the output power of the compressed air engine with rotary air distribution system is about five times as much as that of the compressed air engine with cam air distribution system. The efficiency of two kinds of compressed air engines all declines with a rise in the rotation speed. Furthermore, the energy efficiency of the compressed air engine with rotary air distribution system is higher than that of the compressed air engine with cam air distribution system by approximately 10%. The analyses also indicate that sealing and lubrication are key to practical application of the compressed air engine with rotary air distribution system.