Literature review: Present state and future trends of air-powered vehicles

Due to the climate and energy crisis, many countries and vehicle manufacturers have accelerated research progress on new energy vehicles, which is significant to reduce the use of fossil fuels and decrease the pollution caused by exhaust emissions. Compressed air, as a source of energy and a non-polluting fuel in air-powered devices, is considered to be an opportunity worth trying in the new energy automotive industry. The air powered vehicle is abbreviated as APV, which mainly consists of an air tank, compressed air engine, and control system. In this paper, the current state of new energy vehicles is summarized. The compressed air system and compressed air engine, as the main technologies in air-powered vehicles, are introduced. Based on compressed air energy theory, main evaluation parameters, energy density, and energy conversion efficiency of compressed air are analyzed. The practical methods and the corresponding researches to improve the efficiency of APVs are also presented and discussed, including multistage expansion and energy recovery system. In general, the air-powered vehicle is technologically feasible and practically significant. If the energy loss of the air compression and decompression process is reduced and the utilization rate of compressed air energy is improved, the energy conversion efficiency and driving mileage of APVs will be competitive with traditional vehicles and other new energy vehicles, and its green nature will make it an important place in the future automotive market.