Diesel and Gasoline Engines Diesel and gasoline engines operate on the same mechanism, turning chemical energy into mechanical energy by explosion, but the main difference between them lies in the path of the explosion. In the gasoline engine, the explosion is caused by the combustion flame inside the cylinder that generates a spark of the same The voltage is too high to explode under pressure, and in diesel engines, the fuel explodes automatically without spark because of the high pressure of the diesel. The compression ratio is another difference between the gasoline engine and the diesel engine, because it is much lower in diesel engines, and less in gasoline engines to prevent the engine from igniting, which could have catastrophic consequences, such as the road phenomenon. Some diesel engines may use a glow plug that heats the diesel engine cylinder when it is on, especially in the winter to reach the temperature required to operate properly more quickly.