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 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 fuel tank arrangement for a dual fuel internal combustion engine includes a fuel tank arranged to supply liquid fuel to the dual fuel internal combustion engine, wherein the fuel tank arrangement includes a return conduit connected to the fuel tank and configured to supply leaked fuel from the dual fuel internal combustion engine to the fuel tank, wherein the fuel tank arrangement includes a first fuel separation arrangement positioned in fluid communication between the fuel tank and an outlet to an ambient environment thereof.

A fuel tank arrangement for a dual fuel internal combustion engine includes a fuel tank arranged to supply liquid fuel to the dual fuel internal combustion engine, wherein the fuel tank arrangement includes a return conduit connected to the fuel tank and configured to supply leaked fuel from the dual fuel internal combustion engine to the fuel tank, wherein the fuel tank arrangement includes a first fuel separation arrangement positioned in fluid communication between the fuel tank and an outlet to an ambient environment thereof.

A fuel separation system includes a fuel separator configured to receive a fuel stream and separate the fuel stream, based on a volatility of the fuel stream, into a vapor stream defined by a first auto-ignition characteristic value and a first liquid stream defined by a second auto-ignition characteristic value, the second auto-ignition characteristic value greater than the first auto-ignition characteristic value; and a control system communicably coupled to the fuel separator and operable to receive an input from an engine, the input including an engine operating condition, the control system configured to adjust an operating parameter of the fuel separator, based at least in part on the engine operating condition, to vary at least one of the first or second auto-ignition characteristic values.

A fuel separation system includes a fuel separator configured to receive a fuel stream and separate the fuel stream, based on a volatility of the fuel stream, into a vapor stream defined by a first auto-ignition characteristic value and a first liquid stream defined by a second auto-ignition characteristic value, the second auto-ignition characteristic value greater than the first auto-ignition characteristic value; and a control system communicably coupled to the fuel separator and operable to receive an input from an engine, the input including an engine operating condition, the control system configured to adjust an operating parameter of the fuel separator, based at least in part on the engine operating condition, to vary at least one of the first or second auto-ignition characteristic values.

A method for detecting a sticking tank vent valve in a motor vehicle, a temperature sensor being situated in a tank vent line between the tank vent valve and an inlet point into an intake manifold or into a turbocharger and sticking of the tank vent valve being detected when the absolute value of a correlation of a calculated tank ventilation mass flow and of a signal value of the temperature sensor violates a predefinable threshold value.

A fuel system for a bi-fuel vehicle, which is provided with an engine and an LPG tank connected to each other through a fuel supply line and a fuel return line through which liquefied petroleum gas (LPG) fuel passes, includes: a 3-way valve which is installed in the fuel return line, and selectively opened and closed to move returning LPG fuel to a canister connected with a fuel tank; and a return tube, which branches off from the fuel return line, installed so that the returning LPG fuel passes through the canister in accordance with an operation of the 3-way valve, allowing the LPG fuel of which the temperature is decreased by heat exchange while the LPG fuel passes through the canister to move to the fuel return line.

A fuel system for a bi-fuel vehicle, which is provided with an engine and an LPG tank connected to each other through a fuel supply line and a fuel return line through which liquefied petroleum gas (LPG) fuel passes, includes: a 3-way valve which is installed in the fuel return line, and selectively opened and closed to move returning LPG fuel to a canister connected with a fuel tank; and a return tube, which branches off from the fuel return line, installed so that the returning LPG fuel passes through the canister in accordance with an operation of the 3-way valve, allowing the LPG fuel of which the temperature is decreased by heat exchange while the LPG fuel passes through the canister to move to the fuel return line.

A fuel separation system includes a fuel separator configured to receive a fuel stream and separate the fuel stream, based on a volatility of the fuel stream, into a vapor stream defined by a first auto-ignition characteristic value and a first liquid stream defined by a second auto-ignition characteristic value, the second auto-ignition characteristic value greater than the first auto-ignition characteristic value; and a control system communicably coupled to the fuel separator and operable to receive an input from an engine, the input including an engine operating condition, the control system configured to adjust an operating parameter of the fuel separator, based at least in part on the engine operating condition, to vary at least one of the first or second auto-ignition characteristic values.