Injection pump: classification and repair
Every year the requirements for dieselThe engine by such criteria as power, environmental friendliness and economy only increase. And only an ideal formation of a combustible mixture allows satisfying these requirements. Consequently, the entire injection system must work efficiently, ensuring the smallest spray at high pressure.
Such a system, which unites in one nodethe fuel injector and the pump, is the injector pump. Similarly to the injection pump, the injector pump injects a certain volume of the mixture at the right time. Due to the fact that for each of the engine cylinders there is one pump-injector, in such a system there are no fuel pipes of fuel pump.
The nozzle assembly is as follows: In the cylinder head there are diesel injection pumps. To actuate them on the camshaft there are 4 special cams. The force on the plungers of the injector pumps is transmitted through the rocker arms. Due to the special profile of the drive cam of the pump-injector, the rocker first rises sharply, and then smoothly descends.
At the moment when there is a sharp riserocker, the plunger is pressed downwards with great speed. Therefore, a high pressure arises. When the rocker starts to slowly lower, the plunger also starts to move slowly and evenly upwards. This design allows the fuel to flow into the high pressure chamber smoothly, without creating air bubbles. The time and the injection period control the solenoid valve control pump-injector. To do this, the electronic control unit is supplied with voltage. Even with small deviations in the factory parameters during spraying, the fuel is over-consumed, the engine starts to "make noise".
The diesel pump-injector can be of three types: piezoelectric, electromagnetic, electrohydraulic. With the solenoid valve, the nozzle is installed on both petrol and diesel engines and has a simple device: a nozzle and a solenoid valve with a spraying needle. Electro-hydraulic injector is installed only on diesel engines, which most often work on the system of Komon Rile. Piezoelectric is considered the most perfect for diesel engines.Such a pump injector operates up to 4 times faster than an electromagnetic injector, and doses the injected fuel with maximum accuracy.
Repair of injectors should be carried out whenthe following signs are observed: fuel consumption is markedly increased, failure with a rapid depressing of the gas pedal, leaking fuel or clapping in the exhaust system. Idle turns of the car are unstable: the arrow of the tachometer constantly "jumps" for no reason. Checking the injectors, as well as their repair is done on special stands, therefore it is difficult to repair them yourself: setting the pressure only 10% higher than the nominal causes the engine to malfunction. And even if the operation of the fuel system does not give cause for concern, the diagnosis of the injectors is a process that is recommended to be carried out after every 60,000-70,000 km of auto run.