What are the reasons for the unbalanced fuel supply of diesel generator set fuel injection pump?

1. The reason for the uneven oil supply of the fuel injection pump.

1.The debugging status is different from the usage conditions.

The fuel injection pump is debugged at room temperature on the test bench, while the installed use is used under the conditions of cylinder compression, cylinder temperature up to 500 700, and pressure 3 5MPa, which is quite different. When the locomotive is operating, the temperature of the fuel injection pump and the fuel injector is about 90, which will also cause the viscosity of diesel fuel to decrease, so the internal leakage of the plunger and needle valve coupling increases, and the oil return volume is more than that during commissioning. According to the measurement, the actual amount of oil injected into the cylinder of the fuel injection pump is only about 80% of the debugging amount of the test bench, although the oil pump debugging personnel will consider this factor, but it is impossible to accurately grasp it.

2.Uneven oil supply during commissioning.

When the fuel injection pump is debugged on the test bench, it is required that the unevenness of the oil supply of each cylinder at the rated speed should be 3%. In the actual commissioning process, due to the fact that the length, shape and caliber of the special injector and high-pressure oil pipe of the test bench cannot be completely consistent with the original machine, coupled with the difference in debugging technology, after the installation of the fuel injection pump, the actual oil injected into the cylinder is often 3% uneven.

3.Uneven oil supply caused by mechanical failure.

After long-term use of the locomotive, due to the loose coupling or excessive clearance of the fuel injection pump, the drive gear is worn and the backlash increases, which will also affect the uniformity of oil supply to each cylinder. In addition, the leakage of high-pressure tubing joints due to frequent vibration or insufficient tightening, as well as excessive tightening force, cause the metal of the coupling to fall off and block the tubing, which will also cause uneven oil supply to each cylinder.

1) There is air in the fuel injection pump or the oil pipe joint is loose and leaking.

2) The oil inlet pressure is too low, such as insufficient oil supply in the oil conveying system, too weak the spring of the oil return valve in the fuel injection group, and the blockage of the diesel filter.

3) The oil supply amount adjusted by the column cold is too small (that is, the relative position of the adjusting gear ring and the rack is not right), or the ballast screw of the adjusting gear ring is loose and displaced, so that the oil supply is too small.

4) Excessive wear of the plunger couple.

5) The oil outlet valve is not tightly sealed, which is mainly caused by excessive wear of the oil outlet valve, impurities entering the oil pump and weakening of the spring elasticity of the oil outlet valve.

6) The adjustment screw adjustment that limits the maximum oil volume of the rack in the governor is too small or the adjustment of the throttle handle limiting screw is too small.

The reason why the EFI diesel engine is difficult to start and the oil return is large.

Dear, I'm glad to answer for you! The reasons for the difficulty of starting the EFI diesel engine and the large amount of oil return are as follows:1

Loss of pressure in high-pressure oil circuit: EFI diesel engines need enough high-pressure oil to complete fuel injection. Leaks or other problems in the high-pressure oil circuit can lead to difficult start-up and high oil returns.

2.Clogged fuel filter: The fuel filter is used to filter the fuel entering the injector, and if the fuel filter is clogged, it will affect the fuel flow weight and injection efficiency, resulting in difficult start-up and high oil return.

3.Injector failure: Injectors are one of the key components in EFI diesel engines, they inject fuel into the cylinder to complete the combustion process.

If the injector is damaged or fails, it will lead to difficulty in starting and large oil return. Dry Pure 4Engine Wukai sensor failure:

EFI diesel engines need to monitor the operating status of the engine through various sensors and adjust the amount of fuel injected according to them. If the sensor fails, it will be difficult to start and the oil return will be large.

The detection and adjustment method of fuel supply time of diesel generator set fuel injection pump is as follows:

Step 1: Install the diesel generator set fuel injection pump on the test bench, seal the oil return port, connect the oil inlet pipe, fix the oil supply tooth rod on the oil supply position, loosen the air release screw on the oil pump, start the test bench, exhaust the air, and tighten the air release screw.

Step 2: Adjust the oil supply pressure of the test bench to.

Step 3: Adjust the height of the measuring cylinder and connect the high-pressure oil pipe of the standard injector.

Step 4: Put the control arm on the governor in the oil stop position, loosen the air release screw on the standard injector, and start the test bench, at this time, the oil return pipe of the standard fuel injector should have a large amount of oil return.

Step 5: Place the upper control arm of the governor in the full load position, and at the same time make the plunger of the first cylinder in the bottom dead center position, use a special wrench to rotate the dial slowly and evenly according to the working rotation direction of the oil pump, and pay attention to the fuel flow from the interface of the return pipe of the standard injector. When the oil at the return nozzle has just stopped flowing out (at this time, the plunger just closes the oil inlet hole), it is the starting point of the oil supply of the first cylinder, and the oil supply advance angle can be read from the dial.

If it does not meet the requirements, it can be adjusted by rotating the adjusting screw on the tappet or increasing or decreasing the thickness of the gasket.

Step 6: Take the starting point of the first cylinder oil supply as the benchmark, check and adjust the angle of the oil supply interval of each cylinder according to the above method according to the number of cylinders of the engine and the working sequence of the fuel injection pump. The requirement is that the angular deviation of the oil supply interval between the adjacent two cylinders is not greater than .

Fuel injection pump supply time (term: fuel timing) is a very important parameter for whether the diesel engine is working properly or not. To solve the problem of "incorrect fuel supply time of the fuel injection pump."

Diesel generator sets.

The best way to "run a malfunction" is to readjust its "fuel timing" as required by the instructions.

If the oil supply and oil supply time of each cylinder of the diesel engine are uneven, the combustion process of some cylinders will deteriorate, form carbon deposits or serious aftercombustion, and the heat of diesel combustion can not be used for work, and the temperature of the piston top in some cylinders is too high, resulting in thermal fatigue and melting of materials. Too much oil is one of the main causes of cylinder or piston burnout.

Exclusion method: Adjust the fuel supply of the fuel injection pump in strict accordance with the technical requirements to ensure that the error of the oil volume of each cylinder is not greater than 1. And regularly check and proofread the oil supply.

1.The basis for the readjustment of the fuel injection pump.

According to the exhaust temperature, pressure or smoke color of each cylinder to judge its actual working condition and the degree of combustion of the diesel engine, so as to determine whether the cylinder oil supply is too much or too little, the oil supply time is too early or too late, and then adjust again. By appropriately adjusting the oil supply volume and fuel supply time of each cylinder, the fuel injection pump can supply fuel to each cylinder of the diesel engine according to the principle of on-demand distribution, so as to eliminate the actual difference between each cylinder. FYI (Fujian Yanan Motor Xiaoyanan Answer).

2.Operational technology for readjustment of the fuel injection pump.

1) After the fuel injection pump is installed, adjust the fuel supply time according to the specified standard, and remove the exhaust manifold at the same time to observe the working condition of each cylinder.

2) Start the diesel engine, idle idle for 2 3min, touch the cylinder head near the exhaust port and the fuel injector of each cylinder with your hands, if the temperature of a cylinder is too high, it can be preliminarily concluded that the cylinder has more oil supply.

3) When the temperature exceeds 50, increase the throttle to let the engine run at the rated speed, and at the same time check the smoke color of each exhaust port and listen to the sound of the cylinder. If a cylinder emits black smoke, it means that the oil supply is too large, taking the 135 series diesel engine with more construction machinery as an example, you can pull out the adjusting tooth rod of the fuel injection pump in the direction of oil stopping, loosen the locking screw on the adjusting gear, take a thin iron rod and insert it into the small hole of the oil quantity control sleeve, and tap it with a hammer to turn it to the right, which can reduce the oil supply, and increase it otherwise.

When there is a crisp knocking sound in a cylinder and it is difficult to start, it means that the oil supply has started too early; If the temperature of a cylinder is too high, or even a flame erupts, it may be that the oil supply starts too late. For example, in the 135 series diesel engine, the adjustment of the start time of oil supply for each cylinder is determined by the position of the plunger of the oil pump. When the oil supply start time is too late, the timing adjustment nut and screw should be screwed out a little, and the oil supply start time is too early, then the screw should be tightened.

4) Check the oil supply advance angle.

Generally, the oil spill method can be used to check the advance angle of oil supply, that is, loosen the high-pressure oil pipe joint at one end of the oil pump, remove the joint connecting one end of the fuel injector, turn the oil pipe to the horizontal position, and then tighten the high-pressure oil pipe joint of the oil pump, pull the throttle to the maximum position, open the decompression rocker, until a few drops of diesel fuel come out at the outlet of the high-pressure oil pipe. Wipe the diesel fuel off the outlet of the tubing and slowly turn the flywheel. At the same time, pay attention to the oil level at the outlet of the high-pressure tubing, and stop rotating the flywheel immediately the moment it starts to move upward.

At this time, the engraved line on the tank or body should be aligned between 16 and 20° before the dead center of the flywheel. If there is an oil overflow before the alignment of the two, it means that the oil supply advance angle is too large and the oil supply is too early; If there is more oil overflow, it means that the oil supply advance angle is too small and the oil supply is too late.

1.The oil pump is not producing enough oil.

There are two types of oil pumps for diesel generator sets: gear pumps and rotary lobe pumps. Some gear pumps, the roughness of the joint surface of the pump cover and the pump body is very low, the original design does not add a gasket, if you add a paper pad during maintenance, it increases the end face clearance of the gear, but will reduce the oil output of the pump. However, there is a gasket at the joint surface between the pump and the cylinder block, and if it is missing, the pressure oil from the oil pump will leak outward, causing the oil pressure to drop.

Some rotary lobe pumps, the outer rotor has a chamfer on one side, the other side has no chamfer, if the installation is reversed, the oil output can be reduced by 40 to 60.

In addition, excessive wear and tear between the radial and end clearance of gears or rotors can lead to a decrease in the oil output of the pump and a drop in oil pressure. After repair, the oil pump should be put on the test bench to adjust the opening pressure of the pressure limiting valve to keep it in between. If the pressure is too high, it will accelerate the wear of the oil pump; If the pressure is too low, it will cause the pressure of the main oil duct to drop.

When installing the oil pump, it should be filled with oil first, so as to avoid air in the pump and unable to absorb oil. The connection between the oil pump and the suction plate must be sealed, and if there is an air leak, the oil output of the oil pump will be reduced.

2 The oil filter of the diesel generator set is clogged.

When the oil filter is clogged and the oil cannot pass through, the safety valve on the filter base will be jacked open, so that the oil can enter the main oil channel directly without filtration. However, if the opening pressure of the safety valve is too high to open in time, the internal leakage of the oil pump will increase, and the oil supply to the main oil channel will be reduced, and the oil pressure will also decrease. The oil filter should be maintained on time and the opening pressure of the safety valve should be adjusted correctly.

In addition, if the spring of the safety valve is aged, and the valve seat and the steel ball are not tightly sealed, a large amount of oil will leak and cause the oil pan oil to foam.

3 The return valve is damaged.

If the fatigue of the spring of the main oil return valve is softened or adjusted improperly, and the mating surface between the valve seat and the steel ball is worn or stuck by dirt and closed tightly, the oil return volume will increase significantly, and the oil pressure of the main oil channel will also decrease.