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

Axial-pistondistributorpumpscauses the stop lever, the shaft, the innerlever and the ball pin, to swivel andchange the roller ring’s setting so that thestart of delivery is advanced. The ball pinengages in a slot in the roller ring, whichmeans that the timing-device pistoncannot rotate the roller ring any further inthe “advance” direction until a givenengine speed has been exceeded.In those cases in which the KSB istriggered by the driver from the cab(timing-device KSB), independent of theadvance defined by the timing device (a),an advance of approx. 2.5° camshaft ismaintained (b), as shown in Fig. 13. Withthe automatically operated KSB, thisadvance depends upon the enginetemperature or ambient temperature.The automatic advance mechanism usesa control device in which a temperaturesensitiveexpansion element converts theengine temperature into a stroke movement.The advantage of this method isthat for a given temperature, the optimumstart of delivery (or start of injection) isalways selected.There are a number of different leverconfigurations and operating mechanismsin use depending upon thedirection of rotation, and on which sidethe KSB is mounted.Temperature-controlled idle-speedincrease (TLA)The TLA is also operated by the controldevice and is combined with the KSB.Here, when the engine is cold, the ballpin at the end of the elongated KSBadvance lever presses against the engine-speedcontrol lever and lifts it awayfrom the idle-speed stop screw. The idlespeed increases as a result, and roughrunning is avoided. When the engine haswarmed up, the KSB advance lever abutsagainst its stop and, as a result, theengine-speed control lever is also upagainst its stop and the TLA is no longereffective (Fig. 14).Hydraulic cold-start acceleratorAdvancing the start of injection byshifting the timing-device piston hasonly limited applications. In the case ofthe hydraulic start-of-injection advance,the speed-dependent pump interiorpressure is applied to the timing-devicepiston. In order to implement a startof-injectionadvance, referred to theconventional timing-device curve, thepump interior pressure is increasedautomatically. To do so, the automaticcontrol of pump interior pressure ismodified through a bypass in thepressure-holding valve.Fig. 13Effect of the mechanical cold-startaccelerator (KSB)a Timing-device advance,b Minimum advance (approx. 2.5° camshaft).°cmsFig. 14Mechanical cold-start accelerator(automatically controlled) with temperaturedependentidle-speed increase1 Engine-speed control lever, 2 Ball pin,3 KSB advance lever, 4 Stop.42Injection-timing advance2.5°b00Pump speed pa1234min –1UMK0374EUMK0377Y