IN LINE PUMP COMPONENTS

1.PUMP HOUSING

The pump housing is made of cast aluminum, and contains the pumping mechanism, feed pump, governor mechanism, etc.

2.CAMSHAFT

The camshaft is supported by two tapered roller bearings, and driven by the engine crankshaft via timing gears and the automatic timer. The cam-shaft has cams (the same number as the cylinders of the engine) that actuate the plungers and a cam that actuates the feed pump.

3.TAPPETS

The tappets convert the rotational movement of the cams into the vertical movement of the plungers. Inner and outer rollers are installed where tappets contact cams to increase the bearing surface area.


4. LOWER SPRING SEAT

The lower spring seat supports a plunger spring that pushes the plunger downward, and is de-signed to allow the plunger to turn in the lower spring seat easily. There are two types of lower spring seat: the conventional type and the high-speed type, as shown below. Shims (or an adjusting bolt on the 2D engine) are provided between the lower spring seat and the tappet in order to allow the adjustment of the pre-stroke of the plunger for the No.1 cylinder (or the injection interval of the plungers of the other cylinders).

5. PUMP ELEMENTS

The cylinder is fixed inside the pump housing by a delivery valve holder. The control groove of the plunger acts as a relief for pressurized fuel for the termination of injection when the groove matches the feed hole in the cylinder. The driving face of the plunger fits into the slit of the control sleeve, which rotates the plunger in the cylinder in order to regulate the amount of injection.

6. CONTROL RACK

The control rack is connected directly to the governor, with the rack geared to the control pinion. A control sleeve is fixed to the control pinion by a screw, and they rotate as one. Because the driving face of the plunger fits into the slit of the control sleeve, when the sleeve rotates, the plunger rotates also. When the control rack moves to the right or left, the plunger rotates clockwise or counterclockwise.

IN LINE INJECTION PUMP LUBRICATION

LUBRICATION SYSTEM

An injection pump requires an appropriate lubri­cation system to ensure high-speed operation even under high temperatures and pressures. The lubrication points of an injection pump are roughly divided into parts that are lubricated by engine oil and parts that are lubricated by diesel fuel.

1. LUBRICATION BY ENGINE OIL

In this method, part of the engine oil used to lubricate the engine is diverted to the injection pump in order to lubricate the mechanical gover­nor and driving mechanism of the pump.

2. LUBRICATION BY DIESEL FUEL

The injection pump plungers, delivery valves, injection nozzles, and feed pump piston are lub­ricated by the diesel fuel as it passes through them. (See figure below.)Because the sliding surfaces of these parts are lap-finished the clearance between them is very small. This is especially so in the case of the plungers — they are finished to the extremely close tolerance of about 1 /1000 mm (0.00004 in) to enable them to withstand the very high pres­sures (up to 30 MPa; 300 kgf/cm2; 4,300 psi to which they are subjected, without leakage.Since any foreign material that finds its way into the fuel system can damage or seriously impair the operation of these parts, clean fuel is essential to proper operation of the engine.