(1) Before disassembling the fuel injection pump, shake the engine crankshaft to the position 14 before the top dead center of the crankshaft. This is very convenient for refitting the fuel injection pump in the future, because all the lines and marks are aligned;
(2) When disassembling the fuel injection pump, it is best not to disassemble the fuel injection pump bracket and leave it on the engine. This helps to keep the fuel injection pump and air compressor concentric;
(3) When removing the fuel injection pump, it is most convenient to remove two bolts passing through the long holes from the connector connecting plate. It is best not to disassemble from the middle of the connector, because it is easy to destroy the concentricity of the connector itself;
(4) If the coaxially connected air compressor is to be disassembled, it is convenient to rotate the crankshaft of the engine to the top dead center position of a cylinder compression stroke in advance, and then disassemble it. Because, at this time, the "1" mark on the timing gear of the fuel injection pump in front of the air compressor is aligned with the pointer on the observation hole of the flywheel housing. When reassembling, as long as the installation marks are still aligned.
After the fuel injection pump is removed from the diesel engine, it needs to be removed and repaired. Disassembly and adjustment of fuel injection pump is a special skill, which requires theoretical study and training. During disassembly and assembly, special attention should be paid to:
(1) The working environment must be clean: the coupling of diesel fuel injection pump is very precise, and the mechanism action must be quite flexible. Therefore, contact with dust and abrasive particles should be avoided during disassembly, cleaning, assembly and adjustment. The operation should also be very cautious to minimize the contact and collision between parts.
(2) Couples must be stored in pairs: plunger couples and outlet valve couples must always maintain a strict pairing relationship and must not be confused. Except for the gaskets commonly used in fasteners, all gaskets (such as camshaft axial clearance adjustment gasket and oil outlet valve seat gasket) must remember their relative positions, and pay special attention to the repaired fuel injection pump. Except in special circumstances, each group of components (oil outlet valve coupling, plunger coupling, tappet and its corresponding cam) should usually maintain a constant relative relationship.
(3) Use the specified special tools: special tools are needed to assemble and disassemble the plunger and tappet, and it is not allowed to replace them with surrounding objects at will. Because that will affect the assembly quality and even damage the accuracy of parts.
(4) Remember the relative position relationship between components: when disassembling, pay attention to the relative position relationship between the notch or pit on the fuel supply control rack and the rear end face of the fuel injection pump, the relative position relationship between the sector tooth and the meshing trace on the rack, and the relative position relationship between the sector tooth and the fuel supply control sleeve in the circumferential direction. For reference during reassembly and adjustment. For the repaired or adjusted fuel injection pump, special attention should be paid to the above marking, and it should be re-marked if necessary.
(5) Tighten the screws and nuts moderately: Pay special attention to the clamping screws with sector teeth, the timing nuts on the tappets and the locking caps of the oil outlet valves. Do not tighten them too tightly. In order not to affect the flexibility of the surrounding parts, the parts are not deformed or loose. [top]
Secondly, the removal of the Governor.
Before repairing the fuel injection pump, remove the governor from the fuel injection pump and perform the following steps, as shown in Figure 5-28.
(1) Remove the dipstick seat cover at the rear end of the governor, use a screwdriver to keep the existing position of the adjusting screw of the torque corrector on the governor, remove the lock nut screwed on it, then unscrew the lock nut of the corrector and remove the torque corrector;
(2) Use a 22mm socket wrench to loosen the lock nut of the idle spring screw sleeve and remove the idle spring screw sleeve assembly;
(3) Loosen the two lead-sealed screws and nuts that clamp the speed regulating rod, and let the speed regulating rod loosen the speed regulating spring;
(4) Remove the six bolts fastening the governor cover so that the governor cover leaves the governor housing, remove the lock clip on the rack connecting rod with a screwdriver to separate the rack from the connecting rod, and then remove the starting spring with a needle-nosed pliers;
(5) Unscrew the screw sleeve in the center of the centrifugal weight bracket with a wide screwdriver, and remove the centrifugal weight bracket assembly from the camshaft of the fuel injection pump. [top]
Third, the inspection of the fuel injection pump
In the maintenance of the fuel injection pump, the main wear parts of the fuel injection pump should be checked, as shown in Figure 5-29, so as to make a comprehensive disassembly and maintenance decision, so that the fuel injection pump of the diesel engine can reach its original technical performance and ensure the normal operation of the diesel engine.
1. Rack and sector tooth surface
The mating pair between the rack and the sector tooth surface is an important part in the oil supply control mechanism, as shown in Figure 5-29 (1), and its mating should be relatively tight and easy to push and pull.
During inspection, if it is found that the rack is bent and deformed or the tooth surface is worn, it is difficult to repair and rebuild the tooth surface by straightening, and new parts should be replaced.
If it is found that the push-pull is stuck and the locking position is variable, there may be foreign objects stuck on the tooth surface or individual tooth surfaces are damaged. During maintenance, clean and grind the damaged tooth surface, reassemble and try again.
The push-pull clearance between the rack and the tooth surface, that is, the tooth surface clearance should not be greater than 0. 1mm, the working length should be uniform, and the push-pull force should not exceed 3N. If the resistance is too large or stuck, it should be cleaned and reassembled. If it cannot be repaired, it should be replaced with a new one.
2. Plunger ear and both sides of oil quantity control sleeve
The matched two surfaces are motion control surfaces, which are easy to wear, as shown in Figure 5-29-2. The standard fit clearance is 0.02-0.04 mm If the wear or upsetting deformation exceeds 0.20mm, it should be repaired. When conditions permit, local hard chromium plating can be used to thicken both sides of the plunger ear to achieve the standard fit clearance. Skilled repairmen can also disturb the ears by hammering and carefully polishing, restore the original fit gap, and replace them with new ones when they can't be repaired.
3. Matching surface of oil outlet valve
The mating surface of the oil outlet valve includes the conical surface of the oil outlet valve and the oil outlet valve seat, as well as the decompression ring and the cylindrical surface of the oil outlet valve seat, as shown in Figures 5-29, 4 and 5. It is an important mating surface of fuel injection pump and plays a sealing role. If the wear is serious, the pressure of the sprayed oil will decrease.
4. Plunger mating surface
The mating surface of the plunger refers to the mating of the plunger and the cylindrical surface of the plunger sleeve, as shown in Figure 5-29 (6). It is an important working face of fuel injection pump, which plays the role of lubricating oil pump and sealing. If the wear is serious, the injection oil pressure will be reduced, so the fuel injection pump cannot be used.
5. Tappet cylindrical surface and tappet seat hole
The mating surface between the tappet and the cylindrical surface of the seat hole plays the role of sliding and guiding the tappet, as shown in Figure 5-29 (3). After wear, it will be loose or stuck, which will affect the oil movement of the plunger pump of the fuel injection pump. When the clearance exceeds 0.20mm, it should be updated.
6. Rack and Rack Sleeve Cylinder
The cylindrical fit between the rack and the rack sleeve plays a guiding role in pushing and pulling the rack, as shown in Figure 5-29 (7). Wear will cause the push-pull action of the rack to get stuck. When the gap is too large, it will cause the tooth surface gap between the rack and the sector tooth to be too large. When the gap exceeds 0.40mm, it should be replaced with a new one.
7. Cam
The cam on the camshaft should be replaced when it is seriously worn.
8. Bearing
When the camshaft bearing is seriously worn, it should be replaced with a new bearing to ensure the normal operation of the camshaft. [top]
Four. Disintegration of type A fuel injection pump
When the fuel injection pump is removed from the diesel engine and the governor is removed, the A-type fuel injection pump can be disassembled. Fig. 5-2 shows the exploded view of type A fuel injection pump. There are six sets of single fuel injection pump, which have the same structure and the same action process. Check them one by one when disassembling.
Generally, the disassembly of type A fuel injection pump follows the following sequence:
(1) Dismantle the governor, advancer, smoke limiter and oil transfer pump, and open the inspection window cover on the fuel injection pump side to prepare for disassembly;
(2) Rotate the camshaft, with one tappet for each tappet to the top dead center, clamp the neck of the tappet timing screw with a special tappet positioning plate, and clamp all tappets to the top dead center with six positioning plates;
(3) Put down the fuel injection pump and unscrew the six plugs on the bottom of the pump body facing the six tappets;
(4) Remove the four fastening screws of the bearing cover plate at the advance end, and pull out the camshaft from this end;
(5) Remove the tappet assembly from the screw hole at the bottom of the pump body with special tools: tappet seat and tappet clamp;
(6) Pull out the plunger and its spring and spring seat with special tools: plunger seat and plunger clamp, and put them into special tools in order, without confusion;
(7) Unscrew the tight cover of the oil outlet valve, take out the oil outlet valve stopper, spring, washer and oil outlet valve body, and put them into special instruments in turn, which correspond to the plunger sequence one by one, and shall not be confused;
(8) Pull out the oil outlet valve seat and O-shaped rubber ring from the screw hole of the oil outlet valve tight seat with special tools;
(9) Remove the oil quantity control sleeve with sector gear from the side observation window, unscrew the rack stop screw and pull out the rack;
(10) The camshaft of the fuel injection pump is still in the bearing of the pump body, so it is generally unnecessary to disassemble it. [top]
Verb (abbreviation of verb) Assembly of A-type fuel injection pump
The reassembly sequence of type A fuel injection pump is opposite to the disassembly sequence, which can be reassembled according to the following steps:
(1) Cleaning parts: Before assembly, the parts must be cleaned (usually gasoline or light diesel oil) and dried with anhydrous compressed air. Don't wipe the coupler with cloth, so as not to get fiber. Couplers should be dipped in light diesel oil and other parts should be coated with engine oil. For new coupling parts, protective grease must be heated and melted in engine oil before cleaning.
(2) Insert the plunger sleeve into the pump body: check the mating surfaces, especially the upper and lower end surfaces of the upper flange of the plunger sleeve and the stop surface in the hole of the pump body, and there shall be no burrs, protrusions and foreign objects, so as to prevent the plunger sleeve from being skewed and bent after fitting, causing the plunger to be hairpin, aggravating wear or affecting the flexibility of rack movement. When loading, align the pit on the outer cylindrical surface of the plunger sleeve with the pin hole on the flange side of the inspection window on the side of the pump body, and insert the positioning pin immediately after loading, and the pin end shall not exceed the flange plane.
(3) Installation of the oil outlet valve assembly: Install the oil outlet valve coupling after confirming that the bottom surface of the oil outlet valve seat is smooth and free of foreign objects. Put the oil outlet valve spring, the oil outlet valve stopper and a new copper washer on the oil outlet valve seat in turn, and then screw the oil outlet valve seat into the pump body with an O-shaped rubber ring. The tightening torque is 30-35 N m ... This operation is very critical, and a slight negligence will lead to the leakage of high-pressure oil from here. The end of the sealing seat should be covered with a protective cover.
(4) Install the oil injection quantity control rack: make the scribed lines or pits on the rack flush with the rear end face of the pump body, and gently press it with the rack stop screw to prevent the rack from moving in series.
(5) Install the fan tooth and fuel injection control sleeve assembly: make the opening of the fan tooth fastening screw face the side cover, and the opening is perpendicular to the rack axis. If there is a pit mark on the rack, align the middle tip of the sector tooth with this mark and push the sleeve to make the sector tooth mesh with the rack. For the rack without scribing and marking, the distance between the end of the rack and the rear end face of the pump body can be17.5 mm.
(6) Check the meshing relationship between the sector teeth and the rack: loosen the rack stop screw, push the rack to the end, put a rubber ring on the rack and stick it on the end face of the pump body, and then pull the rack to the end to see if the assembly mark score or the pit mark on the rack is at half the distance between the rubber ring and the end face, as shown in Figure 5-30. When pushing in and pulling out to the bottom, you can see that there is still one tooth in each sector that is not engaged in the rack. If the above is met, the assembly is correct; If there is a slight difference, the oil supply of a single plunger can be adjusted for the repaired pump; If it does not meet the above conditions, it is an assembly error and should be reassembled.
Indiana should be easy. When installing the fuel injection pump, the pulling force should not be greater than 3N.
(7) Insert the plunger: put down the fuel injection pump so that the opening of the side cover faces upwards, clamp the lower end of the plunger with a special plunger, insert the plunger sleeve from the plug hole at the bottom of the pump body, and push and pull the plunger to check whether there is blockage. If there is blockage, loosen the tight seat of the oil outlet valve until the tight seat is tightened without blocking the plunger. Insert the upper spring seat of the plunger from the lower end of the oil injection control sleeve, put the plunger with the lower spring seat and spring on the special plunger seat, insert it from the screw hole on the bottom of the pump body, and align the ear of the plunger with the notch at the lower end of the oil injection control sleeve and push it in. Before pushing in, it must be confirmed that one side of the spiral groove at the top of the plunger is facing upward (that is, toward the observation window).
(8) Install the tappet assembly: Check the total length of the tappet assembly to avoid damaging the top of the plunger and the bottom of the oil outlet valve seat. Insert the special tappet seat into the tappet hole. Note: Only when the slider on the side of the tappet is aligned with the guide groove in the hole can it be pushed in. Push the plunger to the highest point, insert the special tappet positioning plate, and clamp the neck of the timing screw on the upper end of the tappet.
(9) Install the camshaft: Install the rear bearing, cover the rear end of the camshaft with gasket and adjusting gasket, insert the camshaft from the front end (advance end), cover the front end gasket and adjusting gasket, and install the bearing, oil seal, bearing cover gasket and bearing cover plate. Ensure that the axial clearance of the camshaft is between 0.03 and 0.035 meters, which can be adjusted by adjusting the gasket.
(10) Gently pry up the plunger spring seat with a screwdriver, turn the camshaft so that the tip of the cam faces the tappet, and pull out the tappet positioning plate. Do the same, and pull out all tappet locating plates.
(1 1) Reinstall the oil transfer pump and the side observation window cover.
(12) Reinstall the governor.
(13) Reinstall the fuel injection advancer and smoke limiter.
(14) When there is oil after all reloading, use a spring scale to pull the rack, and check the tension, which should not exceed 3N. Turn the camshaft and check whether the fuel injection action of the fuel injection pumps of each cylinder is good. [top]
Six, fuel injection pump installation
The fuel injection pump of 6 1 10 diesel engine is connected with the timing intermediate gear at the rear end of the diesel engine through an air compressor, as shown in Figure 5-27. Therefore, in order to ensure that the fuel injection pump has the correct fuel supply advance angle, the fuel injection pump and the air compressor must be installed correctly. The advancer at the front end of the fuel injection pump is connected with the crankshaft of the air compressor through a connector, and the transmission gear of the fuel injection pump is installed at the front end of the crankshaft of the air compressor. Only by correctly connecting the fuel injection pump advancer, connector and air compressor, and correctly meshing the fuel injection pump transmission gear at the front end of the air compressor with the timing intermediate gear at the back end of the diesel engine, can the fuel injection advance angle of the fuel injection pump be guaranteed. The correct installation operation is as follows:
(1) Uncover the rubber plug on the engine flywheel housing, and turn the engine crankshaft so that the 1-6 top dead center line on the flywheel is aligned with the pointer on the rubber plug hole;
(2) Open the rocker arm chamber cover to ensure that both valves of the first cylinder are closed; Otherwise, rotate the crankshaft again to align the scribed line with the pointer;
(3) Align the mark "1" on the drive gear of the fuel injection pump at the front end of the air compressor with the pointer on the flywheel housing. Observe the correctness of timing gear meshing from rubber plug hole;
(4) Install the connecting plate with long holes on the connector at the rear end of the crankshaft of the air compressor, and tighten the clamping bolts; Install the other half of the connector on the advancer concentrically;
(5) Rotate the crankshaft for one and a half cycles. When the 140 reticle on the flywheel is aligned with the pointer on the rubber plug hole, slowly rotate the crankshaft to stop;
(6) Turn the fuel injection pump so that the engraved line on the casing of the advancer is aligned with the engraved line on the timing indicator of the fuel injection pump, and install the fuel injection pump on the bracket. Adjust the position of the fuel injection pump so that the two halves of the connector are aligned and concentric. At this time, the line 0 on the connecting plate should be aligned with the scribed line on the outer circle of the front steel sheet group of the connector;
(7) Tighten the bolt passing through the long hole of the connector connecting plate and install the fuel injection pump.
(8) Connect the lubricating oil pipe, rotate the crankshaft of the diesel engine, and inject lubricating oil into all lubricating parts.
(9) Connect the oil supply pipeline, turn the crankshaft of the diesel engine, and check the action of the fuel injection pump.
(10) Drive the diesel engine with the starter, make the diesel engine start and run at idle speed, and check the working conditions of all departments. [top]
Seven. Installing a single fuel injection pump
BF6M 10 13EC diesel engine is equipped with a single fuel injection pump, which is an important assembly in the fuel supply system. The six single pumps of a six-cylinder engine are independent of each other and controlled by an oil supply rack. Each unit pump is installed in the corresponding hole on the left side of the cylinder block, fixed by two unit pump fixing bolts and driven by the corresponding cam on the camshaft, so the fuel injection is driven separately.
Figure 5-3 1 is the schematic diagram of the installation method of the unit pump, and the correct installation operation is as follows:
(1) After the diesel engine is turned off, put the speed-regulating rack of the fuel injection pump in the stop position, support the rack from the end with the bolt on the special tool to prevent it from moving in the fuel supply direction, and keep the unit pump in the original assembly position.
(2) Replace individual pumps one by one. Turn the driving cam below the unit pump to its base circle position, and then put the adjusted unit pump into the hole of the unit pump on the cylinder body.
(3) Pre-tighten the fixing bolt of the unit pump with a torque of 5N·m, and then loosen it by about 60 in the opposite direction. Try to turn the unit pump with a torque wrench, and accurately read and write down the value of the rotating torque m.
(4) Turn the monomer pump counterclockwise to make the torque reach (m+1) n m, and then cross-tighten the monomer pump fixing bolts.
(5) The fixing bolts of the monomer pump shall be tightened alternately in three steps, with tightening torques of 7N·m,10n m and 30n m. ..
(6) After the assembly is completed, loosen the bolts on the special tools, remove the special tools, and restore the original assembly state of the whole machine. [top]
Eight, fuel supply system maintenance without disassembly.
The main coupling device of the fuel supply system is very precise, so the requirements for fuel are very strict.
1. Cleaning and maintenance of oil supply system
Most of the faults of diesel engines in use come from the oil supply system, and the main reasons for the faults of the oil supply system are poor quality, uncleanness, incorrect oil number and water content. Therefore, the key to using diesel engine is to ensure the cleanliness of engine oil, and the methods are as follows:
(1) When installing the fuel pipeline, blow the pipeline clean in advance.
(2) Replace the new fuel filter or filter element in time and keep it clean.
(3) Before adding diesel oil every time, the diesel oil should be precipitated for 48 hours in advance, and only the upper ash-free and water-free part should be used; Or add diesel at a designated gas station.
(4) When driving for a long distance, refueling along the way, and stopping for a rest, a part of diesel oil can be released from the oil drain plug at the bottom of the oil tank, and added back to the oil tank after precipitation separation, and the part containing water and sediment at the bottom can be dumped;
(5) Maintain the fuel supply system on time.
2. Maintenance of fuel filter
The fuel filter replacement and maintenance methods of Liuping diesel engine and Jiuping diesel engine are the same, and the purpose of replacement and maintenance is to ensure the cleanliness of fuel and the normal and reliable operation of diesel engine.
(1)6 1 10 diesel filter replacement. 6 1 10 diesel coarse filter and fine filter are shown in Figure 5- 10 and Figure 5- 1, and their maintenance methods are as follows:
Primary fuel filter:
(1) The motor oil in the settling cup should be eliminated every 2000km; Clean the coarse filter element every 8000- 10000 km.
② When cleaning or replacing the coarse filter element, loosen the fixing ring of the precipitation cup with a special ring wrench, remove the precipitation cup, take out the filter element and clean it with kerosene.
(3) When putting it back, be sure to install the sealing ring, and then tighten the fixing ring of the precipitation cup by hand to ensure sealing.
(4) When disassembling the inlet and outlet pipe joints, check whether the gaskets are in good condition, and if damaged, please replace them. The tightening torque of tubing joint is 20-25 N m to ensure no oil leakage.
Secondary fuel filter:
The fine fuel filter plays an important role in ensuring the normal operation of the fuel injection pump and injector in the fuel system. When it is found that the filter element is out of oil or has high resistance, it should be disassembled and replaced with a new filter element in time.
(1) New diesel engines and overhauled diesel engines should be replaced with new filters at the 2500h; When driving normally for 8000- 10000 km, replace the new filter.
(2) When replacing, clamp the oil inlet pipe of the filter, take down the filter with a ring-shaped special tool, and catch the flowing diesel oil with a container.
(3) Clean the sealing surface of the filter base, coat a layer of engine oil on the surface of the rubber sealing ring of the new filter, and then screw the filter to the base and tighten it by hand. Finally, tighten it for half a turn, release the oil pipe, check for leakage and ensure sealing.
④ During the operation of the diesel engine, check the sealing conditions of the coarse filter and the fine filter of each pipe joint again; System bleed.
(2) Replace Jiupingchai fuel filter.
As shown in Figure 5-32, the fuel coarse filter of Jiupingchai automobile diesel engine. The maintenance method is:
(1) The oil in the precipitation cup should be eliminated every 2000km, and the coarse filter element should be cleaned every 8000- 10000km.
② The lower part of the coarse filter is equipped with an oil drain plug 1. Loosen the oil plug, remove oil stains, and pay attention to air removal when tightening.
③ When replacing the filter element, loosen the connecting bolt 6 with a wrench, take down the precipitation cup 3, take out the filter element 4 and clean it with kerosene.
(4) Put the new filter element 4 into the precipitation cup, and screw the filter element and the supporting sleeve arm 2 onto the central connecting rod 9 of the precipitation cup; Pay attention to check whether the base sealing ring 8 is intact, and ensure sealing during assembly.
⑤ Tighten the connecting bolt 6 with a wrench, and the tightening torque is15n m. ..
⑥ Exhaust the air in the oil circuit and the coarse filter with the deflation bolt, and the tightening torque of the deflation plug is 25 N m. ..
The maintenance of fuel fine filtration of Jiupingchai automobile is basically the same as that of 6 1 10 diesel engine. [