The invention provides an automobile engine which does not use oil fuel and achieve the performance of the petrol engines such as large power, little pollution, simple technique, low cost, and long service life. The engine of the invention comprises a fuel system, an air system, a combustion chamber, a power machine, a water supply system and an electric control system. The fuel system and air system respectively transmit fuels and air to the combustion chamber; the fuels in the combustion chamber burn to generate high-pressure fuel gas which pushes energy carrying fluid into the power machine which does work outwards. The fuels of the automobile engine feature simple processing technique, wide source of raw material and low production costs, thus being capable of widely replacing petroleum as automobile fuels and being conductive to energy safety control of the nation. In addition, The inventive automobile engine has simple structure, low failure rate, no hulking parts, easy processing and manufacturing, no mechanisms moving to and fro, little abrasion, small vibration, little noise and pollution and convenient operation and maintenance.