What is a High Pressure Pump?

 Diesel engines and gasoline engines differ in the type of fuel they use and the method of obtaining energy from it. Diesel fuel cannot be combusted by ignition like gasoline. With the help of an injector, compressed air is sprayed into high pressure and combustion is carried out.

Cylinders provide the increase in air pressure. The element that increases the pressure of diesel fuel is the high fuel pump. Its most basic task is to increase the fuel pressure (4-8 bar) coming from the fuel pump to 250-2500 bar levels. There are generally two types of high pressure pumps. Radial type and axial type. Radial type pumps have an eccentric rotating shaft in the center and a spring piston placed around this shaft at 120 degrees like a star. The camshaft, which takes its movement from the crankshaft, rotates and compresses the pistons and the fuel is pressurized in this way. In this high flow system, the pressures are relatively small. In axial type pumps, there are pistons in a cam-shaped slot in the center opposite the movable pusher rollers. The roller moving in this cam mechanism follows a path that will push the counter piston. Thus, the fuel in the center is pressurized and sent. Contrary to the axial pump, the flow rate is low and the pressures are quite high. The fuel under high pressure is sent to the injector via pressure pipes. Some pumps are also assigned to adjust the fuel time and are managed by the brain of the vehicle called the ECU. It receives information from pressure and temperature sensors connected to the brain. A failed fuel pump cannot pressurize the fuel at the desired level and the vehicle cannot perform the combustion process. This interrupts the cylinder operating times and causes the vehicle to run intermittently and make more noise than normal. In addition, in case of a malfunction, the vehicle starts to burn oil instead of fuel and white smoke comes out of the exhaust. Engine oil also has a diesel fuel smell. In such cases, it is recommended to go to the authorized service immediately.