It’s common for engine manufacturers to use a check valve, sometimes called a one-way valve, to allow the flow of fluids to move in only one direction. It’s the traffic cop of a fuel system. These valves are found in almost every mobile and industrial hydraulic system. If there’s a pump, you’ll likely find a check valve that’s preventing backflow from damaging upstream componentry. In addition to performing this important function, check valves are now flexing their versatility by taking on responsibilities they weren’t actually designed for, Parker Hannifin noted in a recent press announcement.

OEM engine manufacturers are now using Parker check valves as fuel pressure regulators in their Class 8 trucks. In other words, these check valves aren’t just controlling the direction that fuel is flowing but controlling the amount of fuel delivered to the engine.

Acting as fuel pressure regulators, check valves can ensure that the pump in the fuel system is not injecting too much or too little fuel into the engine, Parker Hannifin stated. Check valves help regulate a steady, precise amount of fuel to avoid fuel pressure imbalances, which provides greater operational efficiency and helps avoid emissions issues.