The invention determines at least one combustion property of a two-phase fuel gas. The invention comprises providing the fuel gas from substantially only a first phase of the fuel gas to a combustion engine and operating the combustion engine such that a first -value is achieved in the combustion process. The invention further provides the fuel gas from substantially only a second of the two phases of the fuel gas to the combustion engine, wherein the second phase is different from the first phase and wherein the same volumetric air/fuel ratio is kept as when the combustion engine was operated with the first -value. The invention determines a second -value when the combustion engine is operated with the fuel gas from substantially only the second of the two phases of the fuel gas and determines at least one first combustion property of the fuel gas based on the second -value.

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.

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.

An outboard motor includes a vapor separator tank, a downstream fuel supply path, a fuel pump that discharges a fuel in the vapor separator tank into the downstream fuel supply path, a downstream bypass path, and a downstream relief valve provided in the downstream bypass path. A first end of the downstream bypass path is connected to a downstream portion that is closer to the fuel injector than is the downstream check valve in the downstream fuel supply path, and a second end of the downstream bypass path is connected to an upstream portion between the downstream check valve and the vapor separator tank in the downstream fuel supply path. The downstream relief valve opens the downstream bypass path when a fuel pressure in a downstream region that is closer to the fuel injector than is the downstream check valve in the downstream fuel supply path exceeds a first predetermined value.

A lower limit setting portion of a fuel pump control system sets a lower limit value depending on an engine operating mode. For example, it sets a duty ratio of 0% as the lower limit value, when the engine operating mode is in a STOP mode in a turned-on condition of an ignition switch. A duty-ratio calculating portion carries out a feedback control in order that an actual fuel pressure comes closer to a target fuel pressure by use of the lower limit value and calculates a duty ratio for driving a fuel pump by the feedback control. An abnormal condition determining portion determines an abnormal condition based on the duty ratio and pump current. The abnormal condition determining portion further determines based on a remaining fuel amount whether the abnormal condition is caused by a disconnection or whether the abnormal condition is caused by an idling operation of the fuel pump due to fuel shortage.

An engine-driven welding generator that monitors fuel level is provided. The engine-driven welding generator comprises a fuel level monitoring system configured to measure a remaining fuel level in a fuel tank of the engine-driven welding generator, determine a rate of fuel usage of an engine of the engine-driven welding generator, and calculate a remaining run time of the engine based on the remaining fuel level and the rate of fuel usage of the engine

A control system for a dual fuel engine having a liquid fuel supply and a gaseous fuel supply is disclosed. The control system may include at least one sensor operably coupled to a cylinder of the dual fuel engine and configured to monitor cylinder condition and transmit a cylinder condition signal. Additionally, a controller may be communicably coupled with the at least one sensor and the controller may be configured to receive the cylinder condition signal and determine whether the cylinder is operating in an abnormal operating condition. Whereas the controller determines the cylinder is operating in the abnormal operating condition, the controller sends a control signal for the liquid fuel supply to provide an amount of liquid fuel which is greater than an amount of liquid fuel supplied to the cylinder during a normal operating condition.

A fuel system for a motor vehicle includes a fuel pump having a first pump outlet connectable to an engine fuel inlet and a second pump outlet, a fuel pump module including an internal volume, a fuel pump module outlet is arranged in the internal volume fluidically connected to the second pump outlet, and a fuel valve is fluidically connected to the second pump outlet. The fuel valve is operable to fluidically isolate the fuel pump from the fuel pump module when fuel in the internal volume reaches a selected fuel level.

Disclosed is a fuel level estimation device including: an information acquiring unit acquiring information about a closed system internal pressure of a closed fuel vapor system including the fuel tank, a vent passage, and a canister; a flow rate controlling unit controlling, by actuating a negative pressure pump, a flow rate of fuel vapor-containing gas in the closed fuel vapor system; a fuel level estimating unit estimating a fuel level based on a total volume of the closed fuel vapor system and an occupied volume of the gas. The fuel level estimating unit estimates the occupied volume of the gas by using a change in a closed system internal pressure before and after the closed fuel vapor system is subjected to pressure-reducing treatment for a predetermined interval and a reference discharging rate when the gas is subject to the pressure-reducing treatment. An abnormality diagnostic apparatus is also disclosed.

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.