There are two main types of diesel engines:
- Two-stroke diesel engines: A two-stroke diesel engine completes the four-stroke combustion cycle in two strokes of the piston. In this type of engine, the intake, compression, power and exhaust take place in two strokes of the piston, this design is relatively simple, lightweight, and compact. They are less common than four-stroke diesel engines and are typically used in smaller applications such as portable generators, outboard motors, and some light-duty trucks. They have a higher power density compared to four-stroke diesel engines, but they are also less efficient and produce more pollutants.
- Four-stroke diesel engines: A four-stroke diesel engine completes the combustion cycle in four strokes of the piston. These engines are more common than two-stroke diesel engines and are used in a wide range of applications, including transportation, construction, agriculture, and marine. They are also widely used as backup generators and in off-grid power systems. Four-stroke diesel engines are known for their durability, efficiency, and low emissions. They are used in cars, trucks, buses, and large industrial and marine applications.
As I mentioned earlier, within these two main types, there are different types of diesel engines such as direct-injection diesel engine, indirect-injection diesel engine, and common rail diesel engine.
- Direct-injection diesel engines inject the fuel directly into the combustion chamber, this allows for better fuel atomization and improved combustion efficiency.
- Indirect-injection diesel engines inject the fuel into a pre-chamber or a cylinder head, which then vaporizes the fuel before it enters the combustion chamber. This design is simpler and less expensive than direct-injection diesel engines, but it is also less efficient and produces more emissions.
- Common rail diesel engines use a high-pressure fuel injection system, which allows for precise control of the fuel delivery and improved combustion efficiency. This technology is relatively new, and it is becoming more common in modern diesel engines.
Each type has its advantages and disadvantages, depending on the application and the specific requirements of the engine.