The high-pressure fuel pump is one of the main elements of the diesel engine fuel injection system. This device has two functions - it pumps up the right amount of diesel fuel under pressure and regulates the necessary moment of the start of injection.
Purpose and device of injection pump
This pump is based on a special plunger pair that combines a piston (plunger) with a cylinder (bushing). This mechanism is made exclusively of stainless steel. There is a slight gap between the plunger and the sleeve. This is a precision pairing.
It is also worth noting that in recent years, high-pressure fuel pumps have widespread, which regulate the moment of injection by electronic nozzles.
Depending on the design, several types of fuel pumps are distinguished:
- In-line.
- Distribution.
- Trunk.
The inline fuel pump device is as follows. It pumps diesel into the cylinder with a separate plunger pair. By its design, it is the simplest. For example, distribution pumps have several plunger pairs in their design. They pump and distribute fuel across all cylinders.
As a rule, distribution fuel injection pumps are equipped with a pair of plungers. Due to this, they provide a more uniform fuel supply. Unlike in-line, these pumps are distinguished by their low weight and smaller size. Therefore, the details of the distribution fuel injection pump often do not withstand the loads and fail. These pumps are most often equipped with diesel cars.
Trunk high pressure fuel pump
The arrangement of main pumps differs significantly from the design of the previous ones. Such high-pressure fuel pumps are used in the Common Rail injection system, where they perform the function of pumping diesel fuel into a ramp. The main pumps create the greatest pressure in the system. Some devices provide injection under a pressure of 190 MPA. The device of the fuel pump "Mercedes Actros", for example, implies the presence of up to 3 pairs of plungers. Their drive is carried out using a special cam washer or shaft.
These were all varieties of modern fuel injection pumps. The device of each of them, as we have already seen, assumes the presence of at least one plunger pair, the uniformity of the supply and injection of fuel into the system depends on the number and characteristics of which.
If this pump ceases to function, the fuel supply to the combustion chamber will stop. Therefore, it is very important to monitor the state of this mechanism. And finally, we note several signs by which it is possible to determine the malfunction of the injection pump:
- The device mechanism has increased noise during operation.
- A belt slides off the gear of the pump.
- The supply of fuel from the injection pump to the nozzles is disrupted.
- Difficult start of the engine.
- Increased fuel consumption.
- Thick black smoke is pouring from the exhaust pipe . As a rule, this indicates clogged filters, but after replacing them, it is recommended to check the condition of the injection pump.