Working principle of diesel engine
In a diesel engine, clean air is pumped into the cylinders and highly compressed there. As a result, the temperature in the cylinders increases so much that it exceeds the auto-ignition temperature of the fuel. When the piston reaches top dead center (TDC), diesel fuel is injected into the air compressed and heated to a temperature of ~600°C. The fuel is self-igniting and therefore spark plugs are not required.
In a very cold engine, the compressed air may not reach the required temperature. In this case, a preroll is applied. To do this, a glow plug is installed in each swirl chamber of a diesel engine, which warms up the combustion chamber. In addition, the diesel engine is equipped with a cold start accelerator, which is activated using a button on the instrument panel before starting the engine. Under the influence of the cold start accelerator, the injection timing of the high pressure fuel pump (injection pump) moves in the direction of advance, thereby fuel is injected into hot air earlier, a cold engine starts quickly. Once the engine has reached its operating temperature, the cold start button must be released again.
Fuel is sucked directly from the fuel tank by a distribution injection pump (injection pump). It creates the pressure required for injection of about 135 bar, and the fuel is distributed to the individual cylinders according to the ignition order. At the same time, the injection pump regulator controls the injection volume depending on the position of the gas pedal. Through the injectors, diesel fuel at the moment of ignition enters the swirl chamber of the corresponding cylinder. During the compression stroke, the intake air takes the form of a vortex flow in the shape of the swirl chamber and thus optimally mixes with the injected fuel.
Before fuel enters the charge pump, it passes through the fuel filter. There it is cleaned of dirt and water. Therefore, it seems necessary to change the fuel filter according to the maintenance recommendations.
The pressure pump does not require maintenance. All moving parts of the pump are lubricated with diesel fuel. The pump is driven by the crankshaft through the pump drive shaft in the drive chain box.
Since the diesel engine is a self-igniting device, it does not turn off when the voltage in the ignition system is interrupted; for this purpose, it is equipped with a solenoid fuel cut-off valve. When the ignition is turned off, the voltage on the solenoid valve is turned off and it closes the fuel supply channel. His work can be checked by ear (a click should be heard when the valve is activated). When the engine is started with the starter switch, the valve is energized and the fuel passage is opened.
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