The side combustion chamber system in the Diesel engine reduces the noise and strain, and prevents a sudden combustion of the fuel in the main combustion chamber, causing a sudden pressure increase.
How it works
Pure air is sucked in, and pushed into the side combustion chamber. An engine driven, mechanical high pressure pump injects the Diesel fuel at the end of the compression stroke with around 130 bar into the side combustion chamber.The first picture displays the prechamber, in which the fuel is squirted onto a hot ball in the interior where it evaporates and burns. The pressure reaches, through a number of narrow ports, the main combustion chamber.
The next pictures on top show the later developed whirl chamber. Here approx. 50 to 75% of the air, while compressing, is pressed tangentially into the side combustion chamber, mixing by the swirl of the injection intensely with fuel.The fuel-air mixture burns. By the combustion the pressure increases, and pushes the burning mixture by the same port into the main combustion chamber. Prechamber and whirl chamber are entirely or partly independent components which can be exchanged if necessary without having to replace the complete cylinder head.
The side combustion chamber system reduces sudden loads of the crank device. It improves the running comfort of the diesel engine, however, it has disadvantages for the achievement, torque and the fuel consumption. Because nowadays the disadvantages of the direct fuel injection are significantly reduced, by using specialized materials and an electronically controlled injection, direct fuel injection has substituted, almost entirely, the side combustion chamber diesel engines.
The surface of the main- and side combustion chambers extract during the start of the engine large parts of the compression heat. Therefore, an electrical pre-glow is necessary for starting, except when the engine is warm.