The maximum speed of marine high-speed diesel engines is 2100r/min.

Diesel engines are rated at high speeds, rated at 1000 rpm or higher for high speed machines, and rated at 300-1000 for medium speed machines rated below 300 are low speed machines. It can also be divided according to the average speed of the piston. The high speed machine is 9.0~14.2 meters per second, the medium speed machine is 7.0~9.4 meters per second, and the low speed machine is 6.0~7.2 meters per second.

The advantages of diesel engines are high torque and good economic performance. The working process of a diesel engine has many similarities with that of a gasoline engine. Each working cycle also undergoes four strokes of intake, compression, work, and exhaust. However, since the fuel for diesel engines is diesel, its viscosity is larger than that of gasoline, it is not easy to evaporate, and its auto-ignition temperature is lower than that of gasoline. Therefore, the formation and ignition method of combustible mixture is different from that of gasoline engines.