Diesel generator maintenance training diesel article -p61-p65 fuel injection pump

Diesel generator maintenance training diesel article -p61-p65 fuel injection pump

The method for troubleshooting the non-uniform injection of fuel from each cylinder of the diesel generator fuel injection pump is basically the same as the above method. The method of testing and adjusting on the test bench for injection pump is also basically the same.

During the use of the diesel generator diesel engine in the process of using the oil pump oil gauge inspection hole or the oil monitoring port to overflow the diesel, there are generally the following three conditions; 1 plunger sleeve and the pump body contact position oil leakage:

2 The clearance between the internal plunger and the sleeve of the oil pump is too large:

2 The wear gap between the plunger and the plunger sleeve is large.

When it is determined that the plunger sleeve is in contact with the pump body and leaks, each cylinder should be inspected until the missing cylinder is found. After the fault location is found, first remove the tight seat of the oil outlet valve, and then use a special tool to remove the oil outlet valve and the plunger assembly. After these precision components are removed, they must be cleaned with clean diesel fuel, and then the plunger sleeve, the contact surface in the bore of the pump body and the sealing gaskets must be inspected. If you find that the plunger sleeve or gasket is deformed, replace it with a new one. If the contact surface in the bore of the pump body is deformed, use a special tool to grind it. When the grinding amount is large, the relative position of the plunger sleeve can be maintained by increasing the sealing gasket. When performing the final assembly, tighten the tight seat of the oil valve according to the specified torque.

The overhaul or over-adjustment of the fuel advance angle is shown in Figure 2.75. If the timing of diesel engine fuel injection is incorrectly assembled or changes during operation, the diesel engine will have problems such as difficulty in starting, abnormal exhaust emission, unstable rotating speed, and insufficient power. When this kind of failure phenomenon is found, maintenance personnel should first check the injection pump. 2. Injector (1) Composition of the injector The injector is one of the most precise components inside the high pressure oil circuit, mainly by the injectors. Couplings, fuel injectors, injection pressure regulators, inlet and return hose connections. Its role is to spray a certain amount of high-pressure diesel fuel from the fuel injection pump into the combustion chamber in a mist form and form a uniform combustible mixture with the air. For this purpose, the injector must have a certain injection pressure, range and spray cone angle, and the atomization effect should be good. When the injection is completed, the diesel fuel should be quickly cut off to prevent the oil hole of the injector from dripping oil, inside the combustion chamber and Excessive carbon build up around the hole.

Note that different types of diesel engines require different injection pressures. When repairing, it must be adjusted according to the fuel injection pressure specified in the technical specification. After adjusting the pressure too much and assembling the fuel injector to the diesel engine, the fuel injector will not be fueled and other failure phenomena when starting. The sputter assembly is shown in Figure 2-79, and its physical decomposition is shown in Figure 2.80.

If there is a change in the relative position of the fixing screw, if the relative position of the fixing screw is changed, the two fixing screws can be loosened under time pressure, and then the diesel flywheel is rotated so that the two fixing screws are positioned in the middle of each hole. Position, then tighten the two screws.

After the injection pump is disassembled, if it is found that the plunger and the outlet valve are seriously worn, the new parts are generally replaced without repair. The wear position of the plunger and outlet valve is shown in the circle in Figure 2-76.

A diesel engine that has been placed for a long period of time cannot be started or started. The rotational speed is unstable and the smoke is abnormal. This is usually due to the phenomenon that the internal plunger and plunger sleeve of the fuel injection pump are stuck or the individual plunger is stuck in the plunger sleeve. When the pistons of many cylinders in the fuel injection pump are stuck at the minimum position of the fuel supply, the diesel engine is difficult to start, and even if the start-up operation time can not be too long and the power is seriously insufficient. When the internal plunger of the fuel injection pump is stuck at the maximum position of the fuel supply of the plunger sleeve, the diesel engine can start, but after starting, a large amount of black smoke will appear in the exhaust pipe, the speed will be out of control and the diesel engine cannot be stopped. At this time, the diesel engine has occurred. Speeding car accident.

When the diesel generating set maintenance personnel encounters a fuel injection pump with a “flying car” fault, first remove the inspection cover of the injection pump and then manually move the governor shutdown handle up and down to check the rotation of the interior of the fuel injection pump. The situation, as shown in Figure 2-77. After checking the stuck or jammed plunger, use a universal tool to remove the tight seat of the oil valve, and then use a special tool to take out the check valve and the plunger couple. General conditions K When the plunger has stuck or stuck in the plunger sleeve, replace it with a new one. Other fuel injection valve and plunger parts of fuel injection pump should be completely removed and removed, and placed in a clean firewood for cleaning. After the cleaning, the wear condition of these precision parts shall be separately inspected. For the worn-out coupling parts, the new parts are generally replaced without repairs:

For less wearable plungers, perform a sliding test on the plunger assembly as shown in Figure 2-78.

Fig. L77 Month of month SBo machine 7 handle, 96-column from Kd situation B 2-78 Sliding test of plunger coupling When performing the sliding test, tilt the plunger coupling 45. Then, draw out the contact area between the plunger and the cylinder of the plunger sleeve about 1/3, and gently rotate the plunger. If the plunger can smoothly slide down after the hand is released, it is qualified:

If there is a block in the process of sliding down, the plunger should be replaced.

During assembly, the original couple of each cylinder is not allowed to be exchanged and it must be assembled strictly according to the original assembly position marking.

Finally, check the total speed of the fuel injection pump and the full-load fuel supply on the test bench until the fuel supply requirements are met.

2. Injector

(1) The composition of the injector

The diesel generator fuel injector is one of the most precise components inside the high-pressure oil circuit. It is mainly made up of nozzle accessories, injector bodies, injection pressure adjustment components, and inlet and return pipe connectors. Its role is to spray a certain amount of high-pressure diesel fuel from the fuel injection pump into the combustion chamber in a mist form and form a uniform combustible mixture with the air. For this purpose, the injector must have a certain injection pressure, range and spray cone angle, and the atomization effect should be good. When the injection is completed, the diesel fuel should be quickly cut off to prevent the oil hole of the injector from dripping oil, inside the combustion chamber and Excessive carbon build up around the hole.

(2) Faults that are easily caused by injectors

The susceptors easily produce faults: the wear of the nozzles: individual nozzles are blocked by carbon deposits or impurities in the diesel fuel: when there are too many impurities or metal particles in the diesel, the needle valve easily jams in the injector nozzle. Spray nozzle

To be continued...