how to repair P9 injection pump? taking the pump used in weichai X6170 and jichai 8190 as example

Fuel injection pump governor assembly used by X6170Z series diesel engine is injection pump P9. There are mechanical and electronic governors. Let 's introduce the P9 pump with mechanical full stroke governor assembly used on ships. This injection pump belongs to the P series compound multi - cylinder straight plunger pump, with the low pressure dieseltransfer pump being mounted on the injection pump. Connect the rear end of the injectionpump with the governor. The injection pump is composed of injection body, slave cylinders.drive gear and fuel quantity control mechanism. There are 6 slave cylinders in the injection pump altogether.

Summarization of the structure principle: the fuel pump plunger coupler can provide fuel in a given time interval and quantity in two ways.

.( 1) With the function of cam and spring, the fuel pump plunger will move up and down reciprocally to ensure that fuel will be provided in a given time interval.(2)By the help of the governor, the drag link, the control rack and the control pinion ,the fuel pump plunger will move in a rotary way to control the fuel quantity and adapt to the load variations of the diesel engine. Refer to Fig. 3 -9 -2 for the operating principle of the injection pump plunger.

When the plunger is at the position of  the upper part of the plunger is connected withthe outer fuel circuit, The fuel will be transferred from the low pressure fuel cavity of the pumpto the plunger bushing inner cavity. Once the cam rotates, the plunger will move up to the po-sition of b and block the fuel inlet so as to begin pressuring the fuel. If the plunger continues to ascend, the fuel pressure in the high pressure fuel cavity will rise promptly; open the outlet valve and force the fuel into high pressure fuel pipe and the injector. When the pressure reaches a certain value (290bar) , the fuel will push open the needle valve of the injector and be injected into the cylinder through the jet orifice. In case of continuous ascending of the plunger, the fuel injection will keep on till the plunger chute and the fuel inlet being connected.That is to say, when the plunger is at the position of c, it will stop injecting.The b, d and e, indicate the variations of fuel quantity injected when the plunger rotates by a certain angle. Compare the position of b to that of d, we can find that the initial injection times are the same, while d will stop injecting earlier than b. Thus, the total fuel quantity injected of d is fewer than that of b. When the plunger tums to the position of e, the core straightflute and the fuel inlet will be connected ; it will stop injecting fuel because of no longer pressu-ring the fuel ( that is the shutdown position). Once the plunger spring acts on the plunger and forces it to descend , the upper part of the plunger will be filled with fuel again; another cycle is prepared.

It is a mechanical full stroke governor.

In the total working speed range of the diesel engine, a full stroke goveror can regulate any specified rotating speed, To sense the variation of the diesel engine rotating speed by the a-mount of the flying iron centrifugal force, and transfer the displacement of the flying iron to thecontrol rack by the driving of some lever element so that the quantity of fuel supplied can adapt to the outer load t, and to ensure that the diesel engine can run stably and reliably.

Drive(alignment)

Mount the injection bump on the fuel pump support fixed on the engine. It is driven by the injection pump drive gear. The coaxiality of the camshaft of the injection pump and the drivingshaft shall be no more than 0. 1mm, which is ensured by the processing. If the measured coaxi-ality after assembling is more than that, it might be adjusted by adding a gasket to the locatingcurved surface of the pump support ( upward adjustment) and adding a gasket to the connectingparts of the support and the engine ( outward adjustment). The driving shaft couldnt be adjus-ted because it is positioned by the ring ridge.

Adjustment of the fuel supply advance angle ( detailed to contact us email [email protected] ).

Requirement for lead sealing .

On the diesel engine test bench, after pulling the diesel engine to the nominal rotatingspeed and 110% of nominal load ( or as per the supply contract), lead seal the speed limitscrew and the fuel quantity limit screw at the same time. The client shall not unseal it withoutpermission. 3.9.3 Injector.

Figure for the structure features.