Diesel generator set maintenance training diesel engine -p126-p130 timing and oil pressure adjustment

Section 2 Adjustment of Timing and Oil Pressure of Diesel Generator Sets

First, check and adjust timing


After the diesel generator diesel engine is assembled, it is necessary to check and adjust the valve opening and closing time, that is, the valve timing. The timing of the valve timing should be checked after adjustment and adjustment of the valve clearance, and it should be adjusted according to the specification of the random carried technical specification.


During the inspection, a 360° dial should be mounted on the front end of the crankshaft, an adjustable pointer should be placed on the front cover, and then the crankshaft should be turned so that the pointer on the inspection hole of the flywheel housing is aligned with the “0” on the flywheel. The tick marks are shown in Figure 4-8. At this point, adjust the pointer on the front cover so that it aligns with the “0” mark on the dial and fix it. Install a dial indicator on the cylinder head. Place the contact of the dial indicator against the intake valve or the exhaust valve spring seat to be checked. Then turn the crankshaft as indicated by the steering arrow on the dial. Check. At the moment when the dial indicator starts to swing, that is, when the valve starts to open, the angle indicated by the pointer on the dial is the starting angle of valve opening. Then, the crankshaft continues to rotate, and the valve starts to close after being opened to the maximum. At the instant that the indicator of the dial indicator swings from being immovable, the valve is closed, and the angle indicated by the pointer on the dial is the valve closing angle. From valve opening to valve closing, the crankshaft turns through an angle called the valve opening duration.

The diesel generator timing can also be checked by rotating the push rod method, that is, gently prying the valve push rod by hand, while the crankshaft turns to turn the crankshaft. When the push rod is just unable to move by hand, the valve is opened, and the scale indicated by the pointer is the opening angle of the valve. Continue to turn turmeric, when the rod can not be rotated to be able to turn by hand, it means that the valve is closed. At this time, the scale indicated by the pointer is the closing angle of the valve. When checking the timing of valve timing, only the valve of the first cylinder is generally checked. The other backup cylinders are guaranteed by the camshaft. The inspection result of the valve timing shall comply with the technical requirements stipulated in the instruction manual of the diesel engine. The maximum error shall not exceed plus or minus 5... If the valve timing exceeds plus or minus 5 hours. , Should check whether the installation position of the cam gear and the matching gap of the gear meet the requirements.

If it does not meet the technical requirements, you should re-adjust the mounting position of the camshaft drive gear or replace the gear that has been seriously worn out.

Second, the adjustment of oil pressure

There are generally three types of lubrication for diesel engines: pressure lubrication, splash lubrication, and artificial lubrication. When the diesel engine is running, if the oil pressure is too low or too high, it will affect the lubrication quality of the diesel engine. Therefore, the oil pressure must be controlled within the specified range. The oil pressure range of the 135 series naturally aspirated diesel engine should be 0.25-0.35Mpa (25-3.5kgf/cm?), and the oil pressure range of the 6135 series diesel engine should be 0.3- 0.4MI twist (3-4kgf/cm?). Immediately after the diesel engine has started 1m blood, if the reading of the oil pressure gauge does not rise, it shall be stopped immediately for inspection, the cause must be ascertained and the fault must be corrected before starting the engine and observing the oil pressure. During the operation of the diesel engine from low speed to high speed, the oil pressure gradually increases. After the diesel engine reaches the rated speed, the oil pressure gradually returns to the specified value. If you cannot restore to the specified value within 15mh, you must adjust the oil pressure.

The 135 series diesel engine has a pressure regulator on the side of the oil filter. Remove the nut, loosen the lock nut, and turn the adjusting screw with a screwdriver, as shown in Figure 2-91. When screwing in the bolt, the oil pressure should rise: When the bolt is unscrewed, the oil pressure should be reduced. After adjustment, tighten the lock nut. If the oil pressure is still too low after adjusting the oil pressure, the maintenance personnel should check the oil absorption or oil quality.

Section 3 Adjuster and fan belt adjustment and decompression adjustment

First, adjuster adjustment

During the operation of the diesel generator set diesel engine, it often appears that the DC charging current meter pointer does not move, the charging current is too large to persuade the small and other failures. Under normal circumstances, 6Q-195 power storage his charging current is about 13A, the current over the General Assembly caused by the battery life is reduced, not too small, it does not self-accumulation of electricity on time and thus recharge the regulator thus put forward higher requirements . When assembling the test machine, adjust the internal spring of the regulator if the pointer of the charging ammeter indicates that it exceeds 18A.

After starting the diesel engine, if the charging current exceeds the specified maximum charging current allowed by the battery, the current limiting spring inside the regulator should be adjusted so that the spring will be shortened and the current will be reduced; otherwise, the current will be increased. .

During the adjustment process, be careful not to use too much force, it should be performed gently until it meets the requirements.

Second, the fan belt adjustment

The adjustment of the diesel fan belt has certain requirements. Too tight fan belt will increase the wear of the generator bearings, water pump bearings and fan bearings of the straight (cross) flow: the belt is too loose and will cause the fan to have insufficient air flow, which will affect the cooling effect of the cooling water and the generator output voltage will drop. The flow rate of the water pump is reduced and the use effect is not achieved.

Therefore, the fan belt must be adjusted according to the use requirements. Under normal circumstances, in the middle of the triangle rubber belt, when pressing down the tape with a 29-49N (3 to 5kgf) force, it should be able to press 10~20mm, otherwise the tension force of the gantry tape should be adjusted. Adjust the position as shown in Figure 4-9.

Third, decompression adjustment

When the diesel generator set diesel engine is started, it is often difficult to start with the influence of weather or battery power shortage. The method of valve decompression of the diesel engine may be used to reduce the compression ratio and improve the starting resistance line start.

At this point, the operation of the diesel engine into this adjustment method is to open the valve to reduce the crankshaft rotation resistance. If the top is opened too large, then the piston will collide with the valve when the piston reaches top dead center and an accident occurs; if the item is opened too small, it will not be able to function as a decompression.

Therefore, before the adjustment, you must use a tool of appropriate thickness for decompression. For example, before starting, you can insert a flat-blade screwdriver between the shaker and the intake or exhaust valve stem (as shown in Fig. 4.10). One cylinder can use two cylinders when decompression is not enough. After starting pressure relief, remove the screwdriver immediately. When using this method, it is best to put a screwdriver into the rocker arm and valve lever, and then move the flywheel for two weeks to observe whether the valve will collide with the piston. After the diesel engine is started, install the air vent housing at low speed.