Abstract: Propulsion systems for vehicles are provided. The propulsion system includes an engine and a module. The module includes a fuel pump, a check valve, and a relief valve. The fuel pump is configured to supply fuel flow having a pressure. The check valve is configured to receive the fuel flow from the fuel pump, and to allow passage of the fuel flow to the engine. The relief valve is coupled to the fuel pump and configured to release a portion of the pressure of the fuel flow. The relief valve is disposed upstream of the check valve.

Abstract: A liquid fuel strainer assembly includes a filter body of filtration media. The filter body includes a first wall and an opposing second wall shaped to define an enclosed interior space therebetween. A fitting connects the filter body to a fuel pump, and provides fluid communication from the enclosed interior space of the filter body to the fuel pump. A flexible tube is disposed within the enclosed interior space of the filter body. The flexible tube prevents the first wall and the second wall from collapsing toward each other to allow fuel to flow through the enclosed interior space toward the fitting. The flexible tube is not attached to either the fitting or the filter body, and is freely moveable within the enclosed interior space of the filter body.

Abstract: A flow-restricting plug is provided for installation within a vapor recirculation pipe that communicates with a fuel filler pipe. The plug is manufactured of fuel-impervious material and has a cylindrical shape adapted to be mounted by press fit within the vapor recirculation pipe. A flow passage of tortuous shape is formed along the outer circumferential surface of the plug between the opposed ends thereof. The tortuous shape of the flow passage permits the flow of fuel vapor through the plug but prevents the flow of liquid fuel through the plug.