What does a check valve do in the fuel system?

A check valve in the fuel system is designed to allow fluid to flow in only one direction. This function is critical in preventing the backflow of fuel, which could lead to various operational issues, including fuel system contamination and inefficient fuel delivery to the engine. By maintaining a unidirectional flow, the check valve helps ensure that the fuel system operates effectively, providing the necessary pressure and volume of fuel to the engine while preventing any conditions that could compromise performance or safety.

The design of a check valve inherently does not allow for two-way flow, which is why the other choices do not correctly describe its function. It also does not serve the purposes of filtering impurities or regulating temperature, as those tasks are handled by other specialized components within the fuel system.