Marine propulsion equipment is an important component of shipbuilding and plays a decisive role in the ships power, economic operation and environmental performance. In modern ships, the type of propulsion equipment has become extremely rich, and the structure is becoming more and more complex. This paper reviews the development and current status of common marine propulsion systems in China.
1. Diesel engine
Diesel engines are the most widely used marine propulsion power and are suitable for various types of ships. By expanding the diesel specific speed and improving the power, the maximum power and efficiency of the diesel engine can be increased. At present, with the advancement of shipbuilding process and the development of diesel engine technology, diesel engines with higher power and large single-machine power have been produced.
According to the fuel supply method of the diesel engine, it can be divided into three categories: discrete type, semi-continuous type and continuous type. The power system of modern diesel engine is divided into mechanical injection, electronic injection, semi-electronic injection, solid injection and other types, and some new fuel types have been used.
2. Gas turbine
Gas turbines are usually used as main propulsion equipment in large ships, and can also be used as auxiliary propulsion equipment in medium and large ships. Its power output is higher than other propulsion systems of the same displacement, and the propulsion efficiency is very good. Gas turbines are mainly divided into two categories: driven gas turbines and free turbines. Most of them used on ships are driven gas turbines. At present, several domestic manufacturers have developed gas turbines suitable for marine. At the same time, the domestic manufacturing industry is developing towards the research and development of large-scale turbine engines, and the development level is relatively lagging compared with the advanced level at home and abroad.
3. Steam engine
Steam engine is an important imported power equipment used on marine vessels. At present, steam engine-driven bulk cargo ships are mainly widely distributed in the Malacca Strait and the Indian Ocean. In addition, steam turbine system is widely used in ship propulsion and electric power supply, and its application is increasing day by day.
Steam engines are divided into piston engine and turbine. At present, steam turbine is generally used as the main propulsion power of large ships, while steam turbine-driven ship has large output power and good economic performance, and is widely used in small and medium-sized ships. Due to the difficulty of combustion and technical problems, domestic steam turbine development is relatively backward.
4. Nuclear power
The development of nuclear power propulsion technology depends on the related industries such as nuclear depth construction and nuclear safety technology, and the implementation and application of nuclear power propulsion technology need to meet the requirements of international conventions. The application prospects of nuclear power propulsion for Marine vessels are still unclear. At present, only about 20 foreign developed countries have completed related research and development, and nuclear power propulsion is mainly used in nuclear submarines and some research vessels.
5. Internal combustion engine
Internal combustion engines are generally used as auxiliary propulsion power. Its structure is relatively simple, power is large and price is relatively low, so its application range is relatively wide. According to the fuel supply method, it can be divided into three types: gasoline engine, diesel engine and gas engine. According to the structure, there are two-stroke and four-stroke engines, and two-stroke engines are mostly used on board. Its application range is relatively wide, and there are many manufacturers, which can meet the needs of different levels.
6. Electrical propulsion
Electric propulsion is a kind of propulsion power frequently used in shipbuilding industry in recent years. Its advantages are low noise, small active vibration and low fuel consumption. It can also be used to supply electricity for the full system of ships. There are many kinds of electric propulsion, such as DC propulsion system and AC propulsion system. The DC propulsion system is mainly used for small and medium-sized ships, and the propeller can be directly driven by the propeller shaft as the main power supply. The AC propulsion system is suitable for large and medium-sized ships, and the main power supply is generally driven by asynchronous motor or asynchronous controllable motor. Asynchronous controllable motor is the most respected motor type of electric propulsion in recent years. In the application process, since the engine and motor are not affected by the load capacity, the load is constant and the speed is adjustable and controllable, thus avoiding over-load of the power equipment, which can save a lot of fuel.
7. Gas reciprocating engine
Gas reciprocating engine is a kind of combustion engine. Its working process is carried out
