Cooling the fuel


Excess fuel is returned to the tank at the common rail that is not injected into the cylinders. The return fuel is at high temperature as it absorbs heat from the injectors and the jacket of water. As it mixes in the tank with cooler air, the temperature of the fuel supply starts to slowly increase.


For every 10°F increase in fuel temperature above 100°F, the horsepower of the engine is reduced by about 1%. The high temperature of fuel also reduces its ability to lubricate components of the engine fuel system. If the fuel temperature to be supplied to the engine reaches a certain level (typically 140° to 150°F), the genset will shut down due to the safety cutoff. It is especially troublesome if the capacity of the tank is fairly low (e.g., auxiliary tanks), and the temperature of the return fuel is not decreased.

The unit-mounted radiator gensets are typically equipped with fuel coolers. They take advantage of the radiator fan which is powered by the engine to reject fuel heat. Remote-radiator gensets usually require an external fuel cooler to refuse heat from the air. Another option is to furnish the auxiliary tank with a return pump and exchange fuel with the main tank (return hot fuel and replace it with cold fuel) if the fuel temperature exceeds a set point. The return pumps can also be enabled to empty the auxiliary tank manually for maintenance or to prevent overflow conditions via a level sensor.

Contact the Premier Source for Remote Fill Systems

Remote Fill Systems is the premier source for remote fill tanks and systems for generator fueling. We are committed to providing knowledgeable and experienced support to our customers from design and application through startup and commissioning. Our team has many years of experience with fuel oil as well as long experience in industrial process control and mechanical HVAC and piping systems. We have developed innovative and cost-effective products in response to customer needs, such as:


Concealment of the Remote Fill — Architects want to retain the appearance of their designs. The Concealed Underground Remote Fill allows the appearance and beauty of a building to be undisturbed. The Concealed Underground Remote Fill provides a code compliance solution where the required clearance to building openings cannot be achieved with an above ground product.