3 Type of Fuel Injection Pump With Definition and Differents

We know that the diesel engine is a self-ignition engine, that means the combustion is occur by itself.

However, combustion in diesel engines does not appear immediately but there are several trigers that cause combustion to occur. At least there must be two things, first high pressure air with a temperature greater than the flash point of the diesel fuel.

second, the fuel is atomize (pulverize) in the high pressure air. If the two trigers are fulfilled, then combustion will occur spontaneously.

To get atomize fuel, a fuel mechanism is needed. The mechanism will force fuel out of the narrow gap with high pressure. To increase the pressure of diesel fuel, we know a component called an injection pump.

Then, how many types of injection pumps are used in diesel engines? we will discuss in detail.

3 Types of Diesel Fuel Pumps

Maybe you only know there are only two types of injection pumps in diesel engines. But if we see further, there is one type that is actually applied to many recent vehicles.

1. Individual inline pump

An individual pump is a pump mechanism with an individual fuel delivery system. That means that each injector will be served by a plunger mechanism.

It can be say, the number of plungers is the same as the number of injectors.

However, all the plungers are placed together in one pump unit in a line position. That is what causes this pump also called the inline injection pump.

The main components of this type of pump, among others;

  • Camshaft with the number of cam according to the number of plungers
  • plunger which functions to increase fuel pressure
  • Fuel barrel, a small space where the fuel is ready to be sent to the injector.

The way it works, when the crankshafy rotates, the camshaft pump also rotates. The rotation of the camshaft will cause the cam to press against the plunger alternately.

When the plunger is pressed against the cam, the fuel pressure rises immediately so that the fuel is sprayed from the injector.

2. Distributor pump type

Distrubutor pump is a type of injection pump with smaller design. The main purpose of the distributor pump, as a solution for vehicles with limited space.

The main feature of the distributor pump is the injection system. The inline type uses one plunger for one injector, but the distributor type uses a single plunger for all injectors.

The way it works, this plunger will press all the fuel in each fuel barrel alternately. The fuel barrel is placed around the pump shaft.

When the pump shaft rotates, the plunger will press the fuel in the fuel barrel alternately according to the ignition timing.

Even though it has a smaller design, the distributor pump does not have high fuel pressure. Therefore, this type is rarely used for high capacity diesel engines.

3. Continuous pump

Continuous pump is the latest type of diesel injection pump. As I said earlier, this type is actually the most widely applied today.

Continuous pump is an injection pump that is applied to the common direct injection system.

Judging from the physical, this pump has the smallest form of all types that we discuss. The reason is this pump only has a single function.

Its function is only to increase fuel pressure stably at high pressure. The pressure generated is also very high (30,000 - 40,000 PSI)

While the two types above, in addition to increase fuel pressure also regulates the timing and volume of sprayed fuel. So it's reasonable that the form is quite concise.

The way this pump works is like a water pump that uses a turbine even though some types also use membranes. The pump will suppress the fuel and hold the fuel pressure at the applied limit.

How is the fuel spraying technical?

On the common rail system, to spray the fuel is regulated by the injector directly with the ECU command. So, the pump duty only ensures maximum fuel pressure so that once the ECU opens the injector, fuel can be atomized.