Marine diesel engine parts companies introduced the differences between high and low speed marine engines as follows:

1. General marine engines belong to the category of low-speed engines. The engine speed is generally below 800rpm (except for special speed boats), because the marine engine needs to be matched with the propeller, and the propeller speed is about 600-800rpm. Considering the matching efficiency value, too high engine speed is not helpful for this; other large cargo or cruise ship engines use heavy oil (worst oil). This type of engine is generally a two-stroke low-speed engine. Of course, there are also High-power four-stroke medium-speed machines. Medium-speed machines are generally used as auxiliary equipment on ships for power generation and other uses.

2. Automobile engines are more general. General commercial vehicles (heavy trucks) and construction machinery vehicles are mainly diesel engines, and most are six-cylinder four-stroke compression ignition. Passenger cars (cars, etc.) are generally gasoline engines (except special off-road vehicles), which need to be ignited by spark plugs. The engine structure varies with different displacements.