What is the primary function of check valves in a fuel system?

The primary function of check valves in a fuel system is to ensure that fuel flows in only one direction. These valves are designed to prevent backflow, which could potentially allow fuel to return to the source or contaminate the fuel line. By maintaining a one-way flow, check valves help ensure the fuel system remains pressurized and that fuel is delivered efficiently to the engine when needed. This function is crucial for maintaining the operational integrity of the fuel system, avoiding issues that could arise from an improper flow direction.

The other options refer to aspects that are not the primary function of check valves. For instance, control of fuel temperature, enhancement of fuel purity, and increase of fuel efficiency involve different components and mechanisms within the fuel system that do not directly relate to the function of check valves.