Marine diesel engine parts company introduces how Marine diesel engines are classified

There are mainly several classification methods for Marine diesel engines.

(a) According to the way to achieve a working cycle can be divided into four-stroke diesel engines and two-stroke diesel engines.

(2) According to the intake mode can be divided into supercharged diesel engine and non-supercharged diesel engine.

The so-called supercharging means that the intake of the diesel engine is increased by the pressure of the compressor and then enters the cylinder to improve the intake density and increase the power. According to the pressure ratio of supercharging, it can be divided into: low supercharged diesel engine (pressure ratio πk < 1.7), medium supercharged diesel engine (pressure ratio πk=1.7 ~ 2.5), high supercharged diesel engine (πk>2.5) and ultra-high supercharged diesel engine (πk> 3.5).

(3) According to the diesel crankshaft speed and piston average speed can be divided into: High-speed diesel engines (crankshaft speed greater than 1000r/min and piston speed greater than 9m/s), medium-speed diesel engines (crankshaft speed 350 ~ 10OOr/min and piston speed 6 ~ 9m/s), low-speed diesel engines (crankshaft speed less than 350r/min and piston speed less than 6m/s).

The average piston speed Cm is in the formula n---- crankshaft speed (r/min); s---- Piston stroke (m).

The speed of Marine diesel engine is generally selected according to the requirements of use. The main engine of the civil large ship drives the propeller directly through the shafting. In order to improve the propulsion efficiency, the low-speed diesel engine is selected. River and coastal small ships, military ships use medium-speed high-power diesel engines; High-speed gunboats and speedboats require high speed diesel engines with large power, small size and light weight. Diesel engines for Marine power generation are high and medium speed diesel engines. As the main engine of the ship, high and medium speed diesel engines must be equipped with reduction devices.