A pressure-regulating device for a fuel consumption measurement system includes a fuel supply line which supplies fuel to a consumer, a fuel return line, a bypass line which branches off from the fuel supply line, a pressure regulator which sets a free flow cross-section in the bypass line, a pressure sensor arranged at the fuel supply line downstream of where the bypass line branches off, a control unit electrically connected to the pressure sensor, and a pressure-reducing element arranged in the fuel supply line upstream of the pressure sensor and downstream of the branch of the bypass line. The bypass line fluidically connects the fuel supply line to the fuel return line and feeds fuel from the fuel supply line to the fuel return line while bypassing the consumer. The pressure sensor provides pressure measurement values. The control unit regulates the pressure regulator depending on the pressure measurement values.

A fuel supply system for an internal combustion engine may include a plurality of fuel injection pumps, each fuel injection pump being configured to pressurize fuel and provide the pressurized fuel to an associated fuel injector. The fuel supply system may further include a low-pressure fuel supply line fluidly connected to the plurality of fuel injection pumps and configured to provide fuel from a fuel supply tank to the plurality of fuel injection pumps. The fuel supply system may still further include a low-pressure fuel return line fluidly connected to the plurality of fuel injection pumps and configured to return remaining fuel from the plurality of fuel injection pumps to the fuel supply tank. The fuel supply system may include a first fuel cut-off valve disposed in the low-pressure fuel supply line and configured to stop a flow of fuel from the fuel supply tank to the plurality of fuel injection pumps.

A fuel supply device configured to supply fuel from an inside of a fuel tank to an internal combustion engine includes: a cover body that is installed to an upper wall of the fuel tank; a pump unit that is placed on a bottom wall of the fuel tank and is configured to discharge the fuel from the inside of the fuel tank toward the internal combustion engine; and a coupling stay that couples between the cover body and the pump unit. The coupling stay includes: an upper stay that extends on a lower side of the cover body; and a lower stay that is installed to the pump unit and is slidably fitted to the upper stay in a top-to-bottom direction. A stress concentrating portion, which reduces a section modulus to concentrate a stress around the stress concentrating portion, is formed at a specific location of the lower stay.

The present invention provides improved auxiliary fuel tank control systems and methods that avoid the need for locating, identifying, and tapping into a wire leading from the sending unit of the vehicle's primary fuel tank by connecting directly to a diagnostic port of the vehicle which is in communication with the output from the sending unit. Based on information received from the sending unit, embodiments of the invention may automatically cause fuel to be pumped from an auxiliary tank to the primary tank when the amount of fuel in the primary tank drops below a threshold.

Methods and systems are provided for refilling a fuel tank devoid of fuel vapors. In one example, a method may include, prior to an upcoming refueling event, conditioning a fuel vapor-less fuel tank by operating a fuel pump. Operation of the fuel pump may agitate and vaporize the residual fuel in the fuel tank.

A pump unit may include a pump configured to increase a pressure of diesel fuel and discharge the diesel fuel to a fuel passage in which a filter is disposed, and a controller configured to control an operation of the pump. The controller may be configured to execute freeze avoidance control in which the operation of the pump is controlled using an index that indicates a degree of clogging of the filter caused by the diesel fuel freezing. In the freeze avoidance control, the controller may be configured to apply a higher load to the pump as the degree of clogging of the filter indicated by the index is higher.

A fuel-feeding device may include a fuel tank storing fuel therein, a fuel pump configured to feed the fuel in the fuel tank to an engine through a fuel-feeding conduit, an aspirator configured to generate a negative pressure therein using a flow of the fuel flowing through a branched conduit branched from the fuel-feeding conduit, a negative pressure sensor configured to detect the negative pressure generated by the aspirator, and a control device configured to control a revolution speed of the fuel pump. The control device is configured to determine a sign of vapor generation in the fuel stored in the fuel tank based on detection information of the negative pressure sensor.

A returnless fuel system includes a fuel injector, an accumulator, a first fuel pump assembly and a second fuel pump assembly. The accumulator is adapted to store pressurized fuel that is utilized by the fuel injector during prescribed conditions. The first fuel pump assembly is adapted to supply the pressurized fuel at a controlled pressure to the fuel injector. The second fuel pump assembly is in fluid communication with the accumulator and the first fuel pump assembly, and is adapted to provide the pressurized fuel at a controlled pressure to the first fuel pump assembly and the accumulator.

To optimize fuel supply of an engine with a carburetor during engine operation, a throttle opening degree detection sensor detecting a throttle opening degree and a control unit controlling a valve body variably controlling an opening degree of a fuel discharge part or a fuel supply passage based on a map are included. The map includes a plurality of sections divided based on the throttle opening degree and an opening degree of the valve body set for each section. The opening degree of the valve body set for each section is the opening degree of the valve body at which the engine rotation speed is highest in each section. The control unit controls an electric actuator driving the valve body to achieve the opening degree of the valve body set in a section to which the throttle opening degree detected by the throttle opening degree detection sensor belongs out of the plurality of sections.

A fuel system for an internal combustion engine is provided, which comprises a first fuel tank, a fuel filter device, arranged between a low pressure pump operated by an electric motor and a high pressure pump, a first fuel conduit, through which the low pressure pump is arranged to supply fuel to the fuel filter device, and a control device, arranged in connection with an electric motor operating the low pressure pump. An overflow conduit is arranged in connection with a deaeration outlet, arranged in the fuel filter device and the first fuel tank, and the control device is arranged to control the electric motor, in such a way that the low pressure pump is active when the internal combustion engine is turned off for a limited period, whereby fuel may flow from the fuel filter device via the deaeration outlet and the overflow conduit, back to the first fuel tank.