A fuel level sensor detects the level of fuel in a fuel tank. A level signal detected by a float does not change in a full dead zone and an empty dead zone. During normal fuel consumption, the level signal changes according to the consumption amount. Thus when an electronic control unit, or ECU, detects that the fuel level sensor is operating normally, the ECU resets a fuel consumption amount. However, when a small quantity of fuel is supplied, the fuel consumption amount is not reset, and a measurement error may occur during failure detection. Accordingly, the ECU corrects a failure threshold value to avoid misdiagnosing a failure.

The disclosure relates to a method for determining a size of a leak in a fuel tank system. The method includes: starting an internal combustion engine; calculating a stoppage time for a vehicle and/or a temperature difference between the fuel in the fuel tank system and the environment; and checking whether at least one of a plurality of diagnostic conditions is fulfilled. A first diagnostic condition is fulfilled when the stoppage time is longer than a predetermined minimum stoppage time. A second diagnostic condition is fulfilled when the temperature difference is smaller than a predetermined maximum temperature difference. Additionally, when at least one of the plurality of diagnostic conditions is fulfilled, the method includes: evacuating the fuel tank system; recording a time profile of the pressure in the fuel tank system; and determining the size of a leak based on the recorded time profile of the pressure.

A fuel supply device (1) has a valve (13) in a fuel passage between a fuel pump (3) and an engine (5). In a storage portion of an ECU (18-21) is stored a relationship between a fuel pressure and a flow rate, which are required by the engine, and voltage which is supplied to a motor (7). The ECU senses voltages V26, V27, V28 supplied to the motor from a controller (22) when the valve is opened from change points C1′, C2′, C3′ at which a characteristic between the voltage and the current which are supplied to the motor (7) is changed. Then, the ECU corrects the voltage stored in the storage portion on the basis of differences between voltages V1, V2, V5 stored in the storage portion at the change points C1, C2, C3 and the voltages V26, V27, V28 when the valve is opened. In this way, the fuel supply device can correctly control the motor in correspondence to the fuel pressure and the flow rate which are required by the engine.

A method for determining the load status of a filter mounted in a fuel supply system, comprising a fuel supply pump and a control unit for controlling the fuel supply pump, the time curve of the rotational speed of the fuel supply pump being detected over a predetermined period of time, and at least one value of the time curve of the rotational speed and its associated detection time being compared with a comparative value stored in a control unit

A control device is applied to a fuel supply system including a fuel pump that rotates an impeller in a housing and pumps fuel from a fuel tank and a fuel pipe in which fuel discharged from the fuel pump flows. The control device controls the fuel pump. The control device includes an execution device and a storage device that stores a program of a process which is performed by the execution device. In the control device, the execution device performs a coping process of increasing an amount of operation of the impeller when the impeller is deformed and interference with the housing is detected in comparison with a case in which the interference is not detected.

Fuel isolation systems, apparatuses and methods are described. In some embodiments, a system comprises a fuel tank, a fuel pump, an engine, a firewall, a fuel line from the fuel tank to the engine, a connector coupled inline with the fuel line on a cold side of the fuel line, a valve coupled to the connector, an air feed line coupled to an air source and to the valve. In the event of an engine fire condition, a control unit outputs signaling to turn off the fuel pump and operate the valve to introduce air from the air source into the fuel line. The introduced air 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 air.

A valve system of a fuel system for a vehicle may close a jet pump-side flow path when a pressure of fuel supplied from a fuel pump to an engine is lower than a prescribed fuel pressure at engine start-up, and open the jet pump-side flow path when the pressure of fuel is equal to or higher than the prescribed fuel pressure at the engine start-up, thereby improving cold startability of an engine, and may also allow the jet pump-side flow path to be kept in an opened state between a low load region and a high load region of the engine after the engine start-up, thereby smoothly keeping a function of the jet pump after the engine start-up.

In some embodiments, a fuel temperature sensor is located proximate to a vehicle component that is expected to experience fuel gelling, such as near or within a fuel filter, in order to obtain temperature information that accurately reflects the likelihood of fuel gelling occurring within the component. The proximate fuel temperature sensor can provide more accurate temperature information for components such as fuel filters that are installed at the periphery of the vehicle, compared to other temperature sensors that measure oil temperatures or other temperatures of centrally located vehicle components. In some embodiments, the vehicle is automatically started when the temperature indicated by the fuel temperature sensor falls below a startup temperature threshold value, and is automatically stopped after a predetermined time period or after the temperature reaches a shutdown temperature threshold value.

An automatic drain device is configured for use with a fuel water separator filter system. The automatic drain device includes a solenoid, a water-in-fuel sensor, and a controller configured to operate the automatic drain device by activating the solenoid in response to a signal from the water-in-fuel sensor. The automatic drain device may be utilized with suction side and pressure side fuel water separator filter systems. The automatic drain device operates independently of any user input.

A control apparatus for a fuel supply apparatus is used in an engine system. The engine system includes an engine including a fuel injection valve, and the fuel supply apparatus including a fuel pump configured to supply fuel in a fuel tank to a supply pipe connected to the fuel injection valve, and a relief valve provided in the supply pipe. The control apparatus for the fuel supply apparatus includes an executor configured to execute, when the fuel is supplied to the fuel tank, relief pressure control for driving the fuel pump to open the relief valve until a predetermined termination condition is satisfied.