The power supply system for Common Rail diesel engines is divided into two stages: low and high pressure. And if the first is designed for the uninterrupted supply of diesel fuel to the injection pump, then the start and operation of the motor depends on the functioning of the second.
Necessary
- - voltmeter,
- - adapter with scanner,
- - pressure gauge for 1450 atm.
Instructions
Step 1
From the low end point, a high pressure line begins, consisting of:
- a high-pressure fuel pump (TNVD) with a shut-off valve, - a high pressure fuel accumulator (TAVD) with a sensor and a regulator valve;
- motor injectors connected by an electronic control unit (ECU);
- connecting tubes.
Step 2
A diesel engine, unlike a gasoline engine, is very sensitive to the moment of fuel injection. The main parameters of the engine operation (power, diesel fuel consumption, resource) depend on the correctness of the set ignition timing. Changing the position of the crankshaft, at which the timing valves are closed and fuel is injected into the cylinder, at least one risk to "+" or "-", significantly changes the "behavior" of the power plant.
Step 3
Specialists in fuel equipment have always approached the installation of a high-pressure fuel pump (high-pressure fuel pump) with special responsibility, meticulously matching the tightening torque of the drive clutch in accordance with the injection start angle. The Common Rail system nullified all the efforts of the minders, instructing the electronic control unit of the power plant to monitor the specified parameters.
Step 4
From now on, the only task when installing the injection pump into the engine is the articulation of the drive clutch elements. But the electronics not only monitors the moment of injection, it also monitors the formation of high pressure in the fuel accumulator, on the left end of which a corresponding sensor is fixed, which sends signals to the ECU.
Step 5
To check the performance of the power supply system and determine the degree of high pressure, it is necessary to carry out diagnostics. But what to do for those drivers who refused to start the engine and still need to get to the electrician somehow. Buy a scanner that costs ten thousand rubles or more and take it with you? Or buy a pressure gauge for one and a half thousand atmospheres, the price of which is not lower than an adapter, carve out adapters and use it to determine high pressure?
Step 6
If you study the documentation on Common Rail carefully, there is still a way out. To determine the parameters in the TAVD, it is enough to connect a voltmeter to the red wire of the high pressure sensor, turn on the ignition and crank the engine with a starter. At the moment the key is turned to position "II", the voltage from 0, 00 to 0, 07 volts should be removed from the red wire, with the starter on this indicator should be above 0.5 volts, which indicates the presence of a pressure of more than 250 atm. This is exactly how much it takes to start the engine successfully.
Step 7
If the readings of the device exceed 4.5 volts, which is equal to the pressure in the TAVD 1450 atm. and above, the ECU gives a command to the regulator valve, and it dumps fuel into the return line.
