Diesel distributor fuel-injection pumps VE - K-Jet.org

More documents

Recommendations

Info

Axial-pistondistributorpumps38jected fuel quantity must be adaptedto the lower air mass. This is performedby the manifold-pressure compensatorwhich, below a given (selectable)charge-air pressure, reduces the full-loadquantity.Design and constructionThe LDA is mounted on the top of thedistributor pump (Fig. 7). In turn, the topof the LDA incorporates the connectionfor the charge-air and the vent bore. Theinterior of the LDA is divided into twoseparate airtight chambers by a diaphragmto which pressure is applied bya spring. At its opposite end, the springis held by an adjusting nut with whichthe spring’s preload is set. This servesto match the LDA’s response point tothe charge pressure of the exhaustturbocharger. The diaphragm is connectedto the LDA’s sliding pin whichhas a taper in the form of a control cone.This is contacted by a guide pin whichtransfers the sliding-pin movements tothe reverse lever which in turn changesthe setting of the full-load stop. The initialsetting of the diaphragm and the slidingpin is set by the adjusting screw in the topof the LDA.Method of operationIn the lower engine-speed range thecharge-air pressure generated by theexhaust turbocharger and applied to thediaphragm is insufficient to overcome thepressure of the spring. The diaphragmremains in its initial position. As soon asthe charge-air pressure applied to thediaphragm becomes effective, the diaphragm,and with it the sliding pin andcontrol cone, shift against the force of thespring. The guide pin changes itsposition as a result of the control cone’svertical movement and causes thereverse lever to swivel around its pivotpoint M 1 (Fig. 7). Due to the force exertedby the governor spring, there is a nonpositiveconnection between tensioninglever, reverse lever, guide pin, andsliding-pin control cone. As a result, thetensioning lever follows the reverselever’s swivelling movement, causing thestarting lever and tensioning lever toswivel around their common pivot pointthus shifting the control collar in thedirection of increased fuel delivery. Fueldelivery is adapted in response to theincreased air mass in the combustionchamber (Fig. 8). On the other hand,when the charge-air pressure drops,the spring underneath the diaphragmpushes the diaphragm upwards, and withit the sliding pin. The compensationaction of the governor lever mechanismnow takes place in the reverse directionand the injected fuel quantity is adaptedto the change in charge pressure. Shouldthe turbocharger fail, the LDA reverts toits initial position and the engine operatesnormally without developing smoke. Thefull-load delivery with charge-air pressureis adjusted by the full-load stop screwfitted in the governor cover.Fig. 8Charge-air pressure: Operative rangea Turbocharger operation,b Normally aspirated operation.p 1 Lower charge-air pressure,p 2 Upper charge-air pressure.mm 3 /strokeInjected fuelquantity Qep 1LDA operativerangeabCharge-air pressure pp 2 mbarUMK0368E
Load-dependentcompensationDepending upon the diesel engine’s load,the injection timing (start of delivery)must be adjusted either in the “advance”or “retard” direction.Load-dependent start of delivery(LFB)AssignmentLoad-dependent start of delivery is designedso that with decreasing load(e.g., change from full-load to partload),with the control-lever position unchanged,the start of delivery is shiftedin the “retard” direction. And when engineload increases, the start of delivery(or start of injection) is shifted in the“advance” direction. These adjustmentslead to “softer” engine operation, andcleaner exhaust gas at part- and fullload.Fig. 9Design and constructionFor load-dependent injection timing,modifications must be made to the governorshaft, sliding sleeve, and pumphousing. The sliding sleeve is providedwith an additional cutoff port, andthe governor shaft with a ring-shapedgroove, a longitudinal passage and twotransverse passages (Fig. 9). The pumphousing is provided with a bore so thata connection is established from theinterior of the pump to the suction side ofthe vane-type supply pump.Method of operationAs a result of the rise in the supplypumppressure when the engine speedincreases, the timing device adjusts thestart of delivery in the “advance” direction.On the other hand, with the drop inthe pump’s interior pressure caused bythe LFB it is possible to implement a(relative) shift in the “retard” direction.This is controlled by the ring-shapedgroove in the governor shaft and thesliding-sleeve’s control port. The controlDesign and construction of the governor assembly with load-dependent start of delivery (LFB)1 Governor spring, 2 Sliding sleeve, 3 Tensioning lever, 4 Start lever, 5 Control collar,6 Distributor plunger, 7 Governor shaft, 8 Flyweights.M 2 Pivot point for 3 and 4.Add-onmodulesand shutoffdevices1 23478M 256UMK0369Y39
Page 3 and 4: Dieseldistributor fuel-injection pu
Page 5: (prechamber engines and direct-inje
Page 8 and 9: Diesel fuelinjectionsystems:An over
Page 10 and 11: Axial-pistondistributorpumpsMechani
Page 12: Axial-pistondistributorpumpsSubasse
Page 17 and 18: contaminants in the fuel can lead t
Page 19 and 20: Pump assembly with distributor head
Page 21 and 22: Fig. 10Distributor plunger with str
Page 23 and 24: Delivery valve with return-flowrest
Page 25 and 26: - Maximum-speed governing: With the
Page 27 and 28: start-quantity position by the ball
Page 29 and 30: Overrun (engine braking)During down
Page 31 and 32: Injection timingIn order to compens
Page 33 and 34: through a sliding block and a pin s
Page 35 and 36: Fig. 2Schematic of the VE distribut
Page 37 and 38: the torque-control lever tilts arou
Page 39: Power and torque comparison, natura
Page 43 and 44: Cold-start compensationThe diesel e
Page 45 and 46: Design and constructionThe hydrauli
Page 47 and 48: Testing and calibrationInjection-pu
Page 49 and 50: Throttling pintle nozzleThe throttl
Page 51 and 52: Sac-hole nozzle with cylindrical sa
Page 53 and 54: The nozzle-holder body contains the
Page 55 and 56: This necessitates a nozzle holder w
Page 57 and 58: formation in accordance with specif
Page 59 and 60: Closed control loops (Fig. 5)Inject
Page 61 and 62: Table 1. ECU reactionsFailure Monit
Page 63 and 64: High-pressure solenoid valveThe hig
Page 65 and 66: Sheathed-element glow plugs:Tempera

Diesel distributor fuel-injection pumps VE - K-Jet.org

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?