Two Types of Fuel Pump (1)

The importance of fuel pumps

The diesel fuel pump is an important element that affects the performance of the engine. It is prominently manifested in the combustion performance of the engine. Therefore, the improvement of fuel pumps and fuel injectors will play a vital role in improving engine performance. At present, there are only two types of fuel pumps for construction machinery: plunger fuel pumps and PT fuel pumps.

Plunger fuel pumps

The earliest plunger fuel pumps, commonly known as high-pressure oil pumps, are still widely used. After development, pump injectors with distributed fuel pumps, fuel injection pumps and fuel injectors gradually appeared. In fact, these three types belong to the same category of plunger fuel pumps, they are all through the plunger reciprocating motion of the supply of oil. In this paper, these three are referred to as plunger pump, distribution pump and pump injector.

Plunger pumps

Each cylinder of the diesel engine has its own plunger sub-pump, which is arranged on a pump body. Each sub-pump has a high-pressure tubing connected to the injector, which is mounted on the cylinder head, and the fuel can be injected directly into the combustion chamber. The camshaft of the high-pressure fuel pump drives the sub-pump driven by the engine crankshaft through the gear, the CAM and the spring make the plunger up and down reciprocating movement, and each pump supplies oil to each cylinder injector on time.

Distribution pumps

The distribution pump has only one reciprocating plunger to supply oil to the injector, and the reciprocating movement completes the oil supply process once. At the same time, the plunger also rotates, and the oil outlet hole rotates in a certain direction to supply oil to a certain cylinder. The injector of each cylinder must have a tubing connected with the distribution pump, and the oil quantity is controlled by the control ring. The fuel pump is driven by the engine itself, and its CAM structure makes the reciprocating movement times of the plunger in one week of rotation and the number of cylinders the same, to ensure that the distribution pump rotates one week, the engine rotates exactly two weeks, and each cylinder supplies oil on time. Since a plunger must fuel each cylinder once in a rotation cycle, this pump is only used on four and six-cylinder engines.

Pump injectors

The pump injector is actually the plunger fuel pump and injector together, the CAM of the camshaft jacking roller frame, through the jacking rod top shaking arm, rocker arm can rotate on the shaft, the other end can press down to move the plunger, so that the oil supply is controlled by the rack rotating plunger. Below the plunger is the injector, which injects fuel into the cylinder. It moves in the same way that the valve opens and closes. Its CAM is on the same engine camshaft as the valve opening and closing CAM and is driven automatically by the engine.