Diesel generator maintenance training diesel article -p52-p55 high pressure oil

Diesel generator maintenance training diesel article -p52-p55 high pressure oil line two, high pressure oil line

The components of the diesel generator high-pressure oil circuit include fuel injection pumps, governors, high-pressure fuel pipes, fuel injectors, etc. These are the most precise and important components in the diesel fuel supply system. The performance of the diesel generator will be high and low. Directly affect the diesel engine's power output, fuel consumption, mechanical load and work reliability. Therefore, the technical requirements for the repair of the components in the high-pressure oil line are relatively high. Generally, a special technician uses a fuel injection pump test stand or an injector to check the village injection pump assembly or the fuel injector for debugging or repair.

Fuel injection pump

The role of the fuel injection pump is to produce high pressure diesel fuel, and according to the size of the diesel engine's speed and load, it is timed to deliver a certain amount of pressure and quantity of atomized diesel fuel to the combustion chamber through the injector.

The structure of the fuel injection pump has many hinges. According to the different working principle of the fuel injection pump, it can be generally divided into the following four categories:

1 rotor-distribution fuel injection pump: Its characteristic is to rely on the rotation of the rotor to achieve the fuel booster pump oil and distribution.

2 Injector-injector: It is characterized by the combination of the injection pump and the injector. The production of high-pressure diesel and the adjustment of the amount of diesel fuel are completed in the injection pump-injector.

2PT pump: The oil supply is characterized by adjusting the supply of oil according to the relationship of the pressure over time, the adjustment of the oil supply is carried out in the diesel pump, the generation of the high pressure diesel and the timing injection are completed in the injector. .

4 plunger-type fuel injection pump: Its feature is the use of plunger in the reciprocating motion of the plunger sleeve for oil absorption and pressure, the preparation of the cylinder's fuel supply adjustment by changing the plunger stroke to achieve the effective travel. This pump is widely used due to its compact structure, reliable operation, and easy commissioning and maintenance. The following focuses on plunger injection pumps.

The physical appearance of the diesel generator plunger-type fuel injection pump is shown in Figure 2 - as shown. The sedum-type fuel injection pump is mainly composed of an embolic coupling piece, an outlet valve assembly, a roller body, a rotating plunger mechanism, a camshaft, a pump body and ancillary components.

The oil supply principle of the diesel generator plunger injection pump is: When the plunger moves down with the adjustment screw of the wheel body, the diesel oil in the low pressure oil passage of the pump body enters the upper oil chamber of the plunger via the plunger sleeve oil hole: when the plunger As the wheel body adjustment screw moves upwards, the oil hole in the plunger sleeve is closed. As the plunger continues to move upwards, the diesel oil in the upper plunger chamber is compressed and the oil pressure rises rapidly. When the pressure of the diesel oil exceeds the oil pressure When the pressure of the valve spring is reached, the top of the diesel engine opens the oil valve and enters the high pressure oil pipe. * As the piston continues to move upward, the pressure of the diesel fuel in the high pressure manifold and the squirt continues to increase until the pressure of the diesel fuel is greater than the opening pressure of the sprayer. The injector needle valve was opened and the high pressure diesel fuel was atomized into the combustion chamber. The entire oil pressure process continues until the plunger's spiral chute releases the plunger oil hole. The oil hole is opened and the high pressure diesel oil at the top of the plunger flows back through the straight groove on the plunger and the oil return hole on the plunger sleeve to the low pressure oil passage of the pump body. At this time, the oil pressure in the top of the plunger chamber rapidly drops, the injector stops spraying, and the outlet valve also returns to the valve seat under the action of the spring. When the plunger moves downward with the elastic force of the spring along with the roller body, the upper part of the plunger chamber is filled with diesel again, waiting for the next working cycle.

(1) Plunger coupler

The diesel generator plunger assembly will be made from a plunger and a plunger, as shown in Figure 2-65(a). There are straight grooves and spiral chutes on the upper part of the plug, and bumps and small shanks on the lower end, as shown in Figure 2-65(b). The upper part of the plunger sleeve has oil inlet hole and oil return hole rA. Figure 2-65 (c), (d)]. When installing the plunger sleeve, make sure that the oil inlet hole and oil return hole communicate with the low pressure oil passage in the pump body. The groove in the hole is aligned with the locating screw on the pump body and fixed.

The function of the plunger coupler is to move the roller body of the plunger up and down to generate a high pressure diesel fuel which is delivered to the high pressure oil pipe and the injector through the outlet valve assembly.

(2) Outlet valve assembly

The diesel generator outlet valve assembly is one of the precision components in the injection pump. It consists of an outlet valve and a valve seat, as shown in Figure 2-66. The outlet valve assembly is mounted on the top of the plunger sleeve. In order to prevent oil leakage, a seal ring made of nylon is installed on the valve seat. The outlet valve spring is installed on the upper part of the outlet valve, and then it is tightly fixed with the outlet valve. The tightening torque of the oil valve tight seat must not be too large, generally 39-68N·m. If the tightening torque is too large, the plunger sleeve will be deformed and the sliding performance of the coupling will be affected.

The function of the oil valve is to quickly cut off the high-pressure fuel pipe and the diesel oil in the upper oil chamber when the plunger stops supplying oil, so as to prevent the diesel oil in the high-pressure fuel pipe from falling into the fuel injection pump when the plunger is down.

(3) wheel body

The physical appearance of the diesel generator fuel injection pump wheel body is shown in Figure 2-67. The bottom of the roller body is in contact with the cam on the camshaft in the pump body, and the top of the roller body is in contact with the bottom of the plunger. In order to prevent the wheel body from rotating when the A-axis rotates, there are vertical grooves in the pump body and outside. After inserting the roller pin into the groove, the roller and the crank wheel of the wheel are in contact with each other. If the fuel supply time of each cylinder of the fuel injection pump is not pushed, the adjustment screw at the upper end of the roller body can be adjusted.

(4) Turn plunger mechanism (oil control sleeve)

When the plunger assembly of the diesel generator set is fixed in the hole in the upper hole of the housing, a part of the plunger sleeve enters into the oil control sleeve and can rotate relative to the column. Bar cold bumps must be installed in the lack of oil control sleeve to install u, fuel adjustment gear is assembled on the outside of the control sleeve, and the oil adjustment gear meshes with the oil adjustment pinion. When pulling the oil adjustment gear rod, the oil adjustment gear, the oil control sleeve and the plunger rotate together, and the fuel supply can be adjusted by the rotation of the plunger. If the fuel supply of each cylinder does not meet the technical requirements, you can unscrew the locking screw and use a flat-blade screwdriver to gently turn the oil adjustment gear to drive the oil control sleeve and the plunger to adjust the oil volume. When correcting the amount of oil, the lock screw must be fixed for each rotation of the oil level adjustment gear. The function of rotating the plunger mechanism is to change the fuel supply of the fuel injector by changing the effective stroke of the plunger.

The physical appearance of the injection pump oil control sleeve is shown in Figure 2-68.