Inspection and adjustment of fuel supply timing of

2022-08-13
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Inspection and adjustment of fuel supply timing of diesel engine fuel injection pump

in order to check and adjust the fuel supply advance angle, manufacturers generally make the timing mark on the corresponding position of the diesel engine and fuel injection pump when manufacturing diesel engine: the mark of the fuel injection pump's first sub pump starting fuel supply timing, which mostly refers to the timing score on the fuel injection pump coupling (or automatic advancer) and the fuel injection pump bearing cover, as long as the two score lines are aligned, It must be the time when the fuel injection pump begins to supply oil to the I cylinder; The marking of the fuel supply advance angle of diesel engine mostly refers to the pointer on the flywheel housing (or the inspection hole on it) and the angle of the fuel supply advance angle required by the model on the flywheel, and individually refers to the scribed line on the belt wheel at the front of the crankshaft and the pointer on the front cover of the engine body; For multi cylinder diesel engines, when the pointer is aligned with the corresponding angle or scribed line, and there is a gap between the inlet and exhaust valves of cylinder I, it can be sure that it is unloaded at the oil supply advance angle. The meshing mark of the fuel injection pump and the corresponding transmission gear can be aligned with the corresponding timing mark on the meshing gear after the overhaul of the diesel engine. For individual models, pay attention to the connection mark when installing the fuel injection pump

1. Check the fuel supply timing on the engine

the fuel injection pump is fixed on the diesel engine, which may cause inaccurate fuel supply timing due to various conditions. At this time, it is necessary to check the fuel supply timing

(a) when one person rotates the crankshaft to make the piston of cylinder I in the compression stroke (that is, there is a gap between the inlet and exhaust valves of cylinder I), stop rotating the crankshaft when the fixed mark is exactly aligned with the oil supply advance angle mark on the flywheel or crankshaft belt wheel

(b) if the first slave pump of the fuel injection pump starts to supply oil, if the driving needle produces a moving oil timing mark, check whether the timing marking on the coupling (or automatic advancer) is aligned with the marking on the front end of the pump housing. If the two marks are right up, it means that the oil supply timing is correct; If the bid on the coupling has not reached the marking mark of the pump housing, it indicates that the oil supply time is too late; On the contrary, if the mark on the coupling has exceeded the marking of the pump housing, it indicates that the oil supply time is too early

if there is no scribed mark at the front end of the coupling and pump housing, the high-pressure oil pipe of cylinder I of the fuel injection pump should be removed at this time. One person should rotate the crankshaft slowly. When it is about to reach the position of the oil supply advance angle of cylinder I, one person should stare at the oil surface of the oil outlet valve of cylinder I. when the oil surface just moves upward, stop rotating the crankshaft, Check whether the scoring line of the oil supply advance angle on the flywheel or crankshaft belt wheel is aligned with its corresponding pointer (for the convenience of later inspection, a pair of timing marks can be made on the coupling and pump housing at this time)

2. Installation and calibration of oil supply timing

diesel engine overhaul and hydraulic test machine is a set of 3-position full-automatic unit, including steel pipe washing, pressure test, drift diameter, etc., which can complete the pressure test, drift diameter inspection and automatic classification inspection of unqualified steel pipes for oil pipes and casings with or without couplings and ribbed or non ribbed tail The maximum test pressure of oil-cooled electric drum is 100MPa, the pressure test pipe diameter range is 60.3 ~ 177.8 (238 ″ ~ 7 ″), the coupling is 73 ~ 194.5, and the length range of pressure test pipe is 6 ~ 12.7m When the fuel injection pump is reinstalled after maintenance, the fuel supply timing must be checked

(a) rotate the crankshaft clockwise so that the piston of cylinder I is at the specified oil supply start position before the top dead center of the compression stroke, that is, the fixed mark is aligned with the oil supply 4 on the flywheel or crankshaft belt wheel. Its creep resistance and tightening strength are better than that of poly4 fluoroethylene

(b) rotate the camshaft of the fuel injection pump so that the timing marking on the coupling (or automatic advance device) of the fuel injection pump is aligned with the marking on the front end of the pump housing

(c) push the fuel injection pump forward, so that the boss of the driven flange plate is inserted into the coupling and engaged with it. When tightening the two screws of the driving flange plate and the middle flange plate, the "0" mark on the two flange plates should be aligned when the experiment is suspended, so as to ensure that the fuel supply advance angle of the diesel engine meets the requirements

3. Method of adjusting the oil supply timing

when checking the oil supply timing, if the oil supply advance angle is found to be too small or too large, it should be adjusted. The commonly used adjustment methods are:

(1) rotate the pump body to adjust

directly insert the timing gear and spline shaft head to drive the fuel injection pump, and most of them are connected to the body with triangular fixed plate or flange. There are 3 or 4 arc-shaped long holes on the triangular fixing plate and the flange plate respectively. Fix the fuel injection pump with the above method. If the fuel supply timing is not correct, just loosen the corresponding 3 or 4 fixing bolts, turn the pump body appropriately through the arc-shaped long hole to adjust the fuel supply advance angle

when adjusting, turn the pump body by an angle against the rotation direction of the drive wheel to increase the oil supply advance angle; If the pump body is rotated along the driving wheel, the oil supply advance angle can be reduced

(2) rotate the pump shaft to adjust

the fuel injection pump driven by the coupling has two arc-shaped long holes on the connecting plate. When adjusting the fuel supply advance angle, loosen the two fixing bolts on the connecting plate and rotate the camshaft of the fuel injection pump clockwise by an angle to increase the fuel supply advance angle; Turning an angle in the reverse direction can reduce the oil supply advance angle. After adjustment, tighten the two fixing bolts on the connecting plate

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