a common rail diesel fuel system
Common Rail System
How To

How a Common Rail Fuel System Works in the Doosan Engine

A common rail diesel engine has many benefits over a conventional system. Those benefits include better fuel efficiency, more power and less emissions. These systems typically run in the 10,000-30,000 psi range which is a significant improvement. 

Let’s start by looking at what is included in a fuel system. We’ll use the Doosan fuel system as an example. This system includes:

  • a fuel tank
  • a fuel pump
  • a fuel filter
  • an injection system connected by fuel lines
Diesel engines also use an Engine Control Module (ECM)’s to control and open the diesel injector nozzles.

Starting with the tank, the fuel goes through a filter and then feeds to the pump. The pump plays a powerful role in fuel systems, including Doosan’s. The pump has a metering valve, and then a pressure regulator feeds to the common rail. The common rail has a rail sensor on it. That sensor measures how much pressure is in the rail, so if you have a high or low pressure deviation, it will send a code to your ECM. From the rail it goes through the tube or injector lines which are connected to the injectors. The fuel lines provide fuel to each injector with the use of the common rail. The injectors then fire the ECM.

The way that the injector fires and how fast they fire with the higher pressure allows for a much quicker and cleaner combustion inside the engine. 

a fuel system how it works

The caveat with the common rail fuel system is that having clean fuel will be essential for a well functioning system as diesel fuel acts as a lubricant for the injector and its counterparts. In our other article we talk about how water getting into the fuel is one the leading causes of why many diesel injectors fail. Ensuring you get your fuel from a reliable source will be key to maximizing the performance of your fuel system. 

Before you go— We hope this overview gives you a better idea of how a fuel system works. Be sure to check out our other resources for additional information. We also carry many parts that go into a fuel system, including injectors, pumps, fuel lines, and common rails. To ensure your shopping experience is easier, we now sell entire fuel systems for engines D18, D24, and D34