AP-800 ASPHALT PAVER Powerpack Caterpillar


The powerpack consists of a diesel engine, six hydraulic pumps mounted on a pump drive gearbox that is mounted on the engine flywheel housing, and a 55 amp alternator. The alternator supplies the 14 volt direct current electricity needed for various machine instruments and control valves. The hydraulic pumps supply the hydraulic oil pressure used for machine operation and control.

The engine is protected against dust and other foreign material in the intake air by a two stage, paper element air cleaner. Air enters the air cleaner through the inlet tube and is given a cyclonic twist as it passes the pre-cleaner fins. From 75 to 90 percent of the contaminants are separated from the air by the fins. The separated contaminants are thrown from the main air stream and out the dust ejector valve. The pre-cleaned air flows through the main element which removes virtually all (99.9 plus percent) of the remaining contaminants. A safety element inside the main element provides continuous air cleaning if the main element is damaged and also while the main element is being serviced. An indicator shows a red signal when the main element requires servicing.

Fuel for the engine is stored in a 35-gallon (132.5-liter) tank located on the left side of the machine. Fuel used for the screed heaters and for machine washdown is also drawn from this tank.

The pump drive gearbox drives all the hydraulic pumps in the direction of rotation opposite the engine rotation. The function of each pump is:

1.Ground Drive Pump
supplies the hydraulic oil to the ground drive motor which acts through a two speed transmission and an electrical/ hydraulic power locked differential.
2.Right Conveyor Pump
supplies the hydraulic oil to the right conveyor motor which drives the right drag conveyor and right screw conveyor (auger).
3.Left Conveyor Pump
drives the left drag conveyor and left screw conveyor (auger) through the left conveyor motor.
4.Vibrator Pump
powers the screed vibrator motors which turn the screed vibrators.
5.Auxiliary Pump
supplies the hydraulic oil for the various hydraulic cylinders, including the steering system cylinder.