Most of today’s cars are powered by internal combustion engines. The diesel engine also belongs to a group of internal combustion (burning) engines. The energy required to start the vehicle powered by these engines is obtained by combusting the fuel mixture (gasoline, diesel, alcohol, gas, etc.) and air in the cylinders. The air required to burn the fuel is introduced from the atmosphere into the cylinder by suction channels, and the fuel contained in the tank is supplied by the pump that brings it to the injection system. In gasoline (Otto) engine, the mixture of fuel and air is then compressed by the piston, and it fires with a spark from the spark plug. In gas, oil engines (Diesel), the ignition of the fuel is enabled by the high temperature of the compressed air. When the mixture is burned, the gases are released through the exhaust system.
Diesel engines differ in design depending on the number of strokes required to perform a complete working cycle. The diesel engine consists of the engine block, the cylinder head, and the crankcase.
Most motors work on the principle of four-stroke: intake, compression, power, and exhaust. The difference between a four-stroke Otto engine and a four-stroke Diesel engine is in the exhaust. In the Diesel engine, the expansion occurs as a result of the self-ignition of the fuel expansion and air, caused by the high temperature of the compressed mixture. The process is repeated on each cylinder separately so that we get engine operation on each cylinder.
Two-stroke diesel engine
A two-stroke engine is an internal combustion engine that runs the entire cycle in two strokes. The first stroke consists of intake and air compression, while the second stroke contains expansion and exhaust. Two-stroke diesel engines are quite fuel-efficient. Two-stroke engines have been discarded long ago from use in the automotive industry. These types of engines are still used, for example, when starting huge objects, such as large ship engines.
Fuel injection is maybe the biggest difference between Gasoline and Diesel engines. There are two types of injection: direct and indirect.
Direct injection engines achieve higher performance and lower fuel consumption. The injector injects fuel directly into the engine cylinder, that is, into the expansion space, which in this case is located in the engine piston itself.
The advantage of direct injection engines is a relatively small area is needed for combustion. Also, the heat losses are less. Direct-injection engines have higher operating efficiency and therefore have lower fuel consumption.
In the case of indirect systems, fuel is injected into the pre-chamber. By compressing air, a whirlpool is created in the chamber. When injected, the fuel will mix evenly with the compressed air. Such engines work much quieter and softer than direct-injection engines.
Nowadays, the indirect systems are among the older technologies, but it is this system that made the use of diesel motors very popular in its very beginning.