Fuel is sucked in by the high pressure fuel pump (injection pump) directly from the tank. In the injection pump, the fuel is compressed to the pressure required for injection. Injection is carried out in the same order as the ignition order in a gasoline engine.
To reduce the proportion of harmful substances in the exhaust gases, diesel engines have a diesel oxidation catalytic converter. At the same time, the recirculation system ensures a significant reduction in the content of nitrogen oxides in the exhaust gases. This is achieved by supplying exhaust gases to the engine intake air, which reduces the oxygen concentration in the air entering the engine cylinders. This results in a delayed ignition and a lower combustion temperature, which ultimately reduces the formation of NOx. However, the exhaust gas recirculation process must be accurately metered, otherwise carbon emissions increase. To do this, the amount of air drawn in is determined by the meter, which allows the electronic device to control the recirculation process.
When the engine is cold, the compression temperature of the air is insufficient to ignite the fuel. In this case, preheating is required. For this purpose, an electric glow plug is installed in each cylinder of the engine.
The duration of the glow depends on the outside temperature and is regulated by a special relay.
Fuel injection into the cylinders can be carried out in three ways: through the prechamber, swirl chamber or directly into the combustion chamber.
At pre-chamber injection diesel fuel is injected into the prechamber of the respective cylinder. The hot fuel mixture ignites immediately. However, the volume of oxygen contained in the prechamber is sufficient to burn only a portion of the injected fuel. The remaining unburned part of the fuel under the action of combustion pressure is thrown into the main combustion chamber, where complete combustion of the fuel occurs.
At vortex chamber injection fuel is injected into a chamber separated from the main combustion chamber. The difference from the pre-chamber injection is a different implementation of the connecting channel between the vortex and main chambers. Here, when compressed, a strong air swirl occurs in the swirl chamber, which contributes to good mixing of air with injected fuel.
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