Fuel Filter

Trouble-free operation of a diesel injection system is possible only with filtered fuel. Fuel filters help reduce damage and premature wear from contaminants by retaining very fine particles and water to prevent them from entering the fuel injection system. As shown in Figure 1, fuel systems can contain one or more stages of filtration. In many cases, a course screen is also located at the fuel intake located in the fuel tank.

Two stage filter system typically uses a primary filter on the inlet side of the fuel transfer pump and a secondary filter on the outlet side. The primary filter is required to remove larger particles. The secondary filter is required to withstand higher pressures and remove smaller particles that can damage the engine components. One-stage systems remove larger and smaller particles in a single filter.

Figure 1. Examples of Low Pressure Fuel Systems for Heavy-Duty and Light-Duty Diesel Vehicles