The ship's low speed diesel engine is the ship's main engine, which mainly powers the ship.According to the characteristics of working cycle, low speed machine can be divided into two - stroke low - speed machine and four - stroke low - speed machine.

(1) two-stroke low-speed diesel engine

Two-stroke low speed diesel engine is the main product of ship low speed diesel engine, as the main engine of large ships.The progress of two-stroke low-speed machines from ordinary models to modern models is mainly reflected in the improvement of power and the reduction of unit fuel consumption, which meets the requirements of international Marine environmental protection.The large increase in power greatly satisfies the need of building large and large ships.The reduction of unit fuel consumption meets the requirement of environmental protection engine and meets the requirement of environmental protection engine.

(2) four-stroke low-speed diesel engine

Four-stroke low speed diesel engine is a kind of ship low speed diesel engine.The structure is the same as the two - stroke low - speed machine, the cylinder and crankcase upper and lower parts.The crankcase works in the same way as the four-stroke machine, and the cylinder works in the same way as the two-stroke machine.According to the size of the model, the number of cylinders is generally between 4 and 8, and the stroke and unit fuel consumption are close to the two stroke low-speed machines with the same number of cylinders, which can also meet the requirements of international Marine environmental protection.However, the design speed can reach 390 r/min.

Japanese manufacturers usually have four stroke diesel engine at low speed Marine diesel engine design patents, and is often used in the manufacturing all kinds of ships, such as all kinds of carrier, engineering ship and Marine fishing boats as the host.

Due to high reliability and low quality fuel for combustible use, large low-speed diesel engine has always been the main engine type of Marine propulsion machinery.Second, the maintenance cycle of low-speed machines can reach tens of thousands of hours, and high-speed machines to 10,000 hours or more must be serviced.Finally, because the structure of the low speed machine is larger than that of the high speed machine, the speed is lower, so the operation is relatively stable.

The advantages of low speed, age, wear and maintenance are better than high-speed, high-speed is the advantages of small volume, is suitable for loading and other volume limitation, the disadvantage is that maintenance trouble, life is not as good as good at low speed.