medium-speed engine

A medium-speed diesel engine operates at 400–600 revolutions per minute and is typically a four-stroke engine. These engines are lighter and more compact than low-speed engines, making them suitable for applications where space is a concern. However, they usually require a speed-reducing gear between the engine and propeller, and they tend to have a higher fuel consumption rate compared to low-speed engines.1

Diesel engines, in general, convert chemical energy from fuel into mechanical energy. They work by compressing air to a high temperature, then injecting diesel fuel, which ignites and expands to power a piston. While efficient, diesel engines can emit higher levels of pollutants like particulate matter and nitrogen compounds compared to gasoline engines.2