A fuel return device includes a fuel collector and a return system. The fuel collector is located in a passage between a fuel tank and a vapor fuel processing device that processes vapor fuel discharged from the fuel tank. The fuel collector collects the fuel and stores the collected fuel as a storage fuel. The return system extends from the fuel collector, and is connected to a low-pressure generation part that generates a low pressure by a flow of fuel refueled through a filler pipe into the fuel tank, to return the storage fuel to the fuel tank.

A hermetically sealed fuel tank system includes a hermetically sealed fuel tank, a fuel pump configured to supply fuel from within the hermetically sealed fuel tank to an internal combustion engine, and a pressure regulating valve. The pressure regulating valve is disposed within the hermetically sealed fuel tank and is configured to regulate the fuel pressure of the fuel supplied from the fuel pump to the internal combustion engine. The pressure regulating valve includes a pressure regulating chamber and a backpressure chamber partitioned by a diaphragm. An ambient air introduction passage is fluidly connected to the backpressure chamber and is configured to introduce air from the atmosphere outside the fuel tank into the backpressure chamber.

Methods and systems are provided for pressurizing a step chamber of a direct injection fuel pump. In one example, the step chamber may be pressurized to a pressure higher than an output pressure of a lift pump, the lift pump supplying fuel to the direct injection fuel pump. The pressurization of the step chamber may occur during at least a portion of a pump stroke of the direct injection fuel pump.

A fuel pump system of a hybrid vehicle is provided. The fuel pump system prevents a fuel pump from continuing to operate when fuel is exhausted, whereby the fuel pump may be damaged. The pressure of fuel is measured in response to exhaustion of fuel, and when the pressure of fuel is low, fuel is circulated within the fuel pump instead of being supplied to the engine side, thereby preventing the fuel pump from being stuck due to frictional heat

A fuel pump system of a hybrid vehicle is provided. The fuel pump system prevents a fuel pump from continuing to operate when fuel is exhausted, whereby the fuel pump may be damaged. The pressure of fuel is measured in response to exhaustion of fuel, and when the pressure of fuel is low, fuel is circulated within the fuel pump instead of being supplied to the engine side, thereby preventing the fuel pump from being stuck due to frictional heat

A low pressure regulator for a high pressure fuel pump includes a standard damping orifice, providing a constant level of piston movement damping by enabling a fluid pathway between a spring chamber and a return line. The low pressure regulator also includes a further damping orifice, which is covered by the piston when discharge port holes are open, the further damping orifice providing a further, variable level of piston movement damping by providing a further fluid pathway between the spring chamber and return line. The further damping orifice is open in a hydraulic accumulator mode and closed in a regulator mode, thereby reducing pressure spikes caused by insufficient spring chamber filling.

A fuel supply device includes a fuel pump, a filter case that houses a fuel filter, and a port member joined to the filter case, a fuel pumped by the fuel pump from inside a fuel tank is filtered by the fuel filter and supplied from inside the filter case toward an internal combustion engine, and the port member integrally includes a plurality of fuel ports that communicate from inside of the filter case to outside of the filter case.

A fuel supply device includes a sub-tank, a pump unit, a jet pump, and a connection structure connected with the pump unit and the jet pump. The connection structure has a guide part that is provided to the pump unit and guides the pressurized fuel toward the bottom in an axial direction, a pressurizing part that is provided to the jet pump and is fitted to the guide part from a side of the bottom in an axially slidable manner, to which the pressurized fuel is guided from the guide part, a shock-absorbing member that has a low spring constant that is predetermined and mitigates an axial impact between the guide part and the pressurizing part, and a sealing member that has a high spring constant higher than the low spring constant of the shock-absorbing member and radially seals a space between the guide part and the pressurizing part.

A valve, a multi-functional combination valve and a CFLVV valve simultaneously achieve the functions of a refueling limit valve and a rolling-over valve in a fuel tank. The valve body includes a valve core accommodating cavity, and first and second inflow passages, a first discharge port, and a second discharge port communicating therewith are provided. The valve core accommodating cavity includes two independent vertical-sliding first valve core assemblies and second valve core assemblies for opening or closing the first discharge port and the second discharge port. The pressure maintaining part is connected to the second discharge port and contains a certain opening pressure. After the first valve core assembly closes the first discharge port, and a certain pressure value has to be reached in the valve core accommodating cavity, the pressure maintaining part will open the second discharge port, and the fluid will flow out of the second discharge port.

Fuel isolation systems, apparatuses and methods are described. In some embodiments, a system comprises a connector coupled inline with a fuel line on a cold side of the fuel line, a valve coupled to the connector, a fluid feed line coupled to a fluid source and to the valve. In the event of an engine fire condition, a control unit outputs signaling to stop pumping the fuel and to operate the valve to introduce fluid from the fluid source into the fuel line. The introduced fluid provides a siphon break in the fuel line such that the only fuel that can pass the firewall is the remaining fuel in the fuel line downstream of the connector and the introduced fluid.