Marine diesel engines are generally divided into high-speed, medium-speed and low-speed diesel engines. The main performance indicators of the three types of diesel engines are listed below.
Marine diesel engine parts Marine main engines work most of the time under full load and sometimes operate under variable load. Ships are often sailing on bumps, so marine diesel engines should be able to work reliably under conditions of pitch 15°-25° and heel 15°-35°. Most ships use supercharged diesel engines, and low-power non-supercharged diesel engines are only used on small boats. Most low-speed diesel engines are two-stroke engines, medium-speed diesel engines are mostly four-stroke engines, and high-speed diesel engines are both. The scavenging forms of the marine two-stroke diesel engine include reflux scavenging, port-valve direct current scavenging and opposed piston port scavenging. Heavy-duty medium and low-speed diesel engines widely use heavy oil as fuel, while high-speed diesel engines still use light diesel.
The low-speed diesel engine directly drives the propeller. In order to make the propeller have high propulsion efficiency, a lower speed is required. The medium and high-speed diesel engines drive the propeller through the gear reduction box. The gear box is generally equipped with a reversing mechanism to achieve the reverse rotation of the propeller, but the low-speed diesel engine and some medium-speed diesel engines can reverse themselves. Medium and high-speed diesel engines are also electrically driven by generators-motors-propellers. When the required power is large, multiple machines can also be used in parallel, and at low speeds, only one host can be used to work, thereby improving the operation economy and reliability. When two main engines are installed on the same ship, they are divided into a left engine and a right engine according to the installation position and propeller steering.
L28/32 diesel engine parts talk about the main development trend of marine diesel engines: improving supercharging technology (secondary supercharging, super high supercharging and supplementary combustion supercharging, etc.) to increase the power of the single engine; improving the combustion process and burning low quality Fuel oil and use of waste heat to improve economy; improve reliability and extend service life; use fault prediction and monitoring to achieve automatic remote control of diesel engines.