Method for suctioning liquid fuel from a liquid trap in a fuel tank; and fuel system for a motor vehicle

Patent metadata

Field	Value
Publication number	US-9631586-B2
Application number	US-201514720011-A
Country	US
Kind code	B2
Filing date	May 22, 2015
Priority date	May 23, 2014
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A method for suctioning liquid fuel from a liquid trap in a fuel tank of a motor vehicle, includes generating a negative pressure in a gas compartment or headspace of the fuel tank, applying the negative pressure to the liquid trap through a suction line, wherein the liquid trap has a collection container collecting liquid fuel during venting of the fuel tank, and at least partially suctioning the liquid fuel located in the collection container through the suction line into the gas compartment or headspace.

First claim

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein:

1. A method for suctioning liquid fuel from a liquid trap in a fuel tank of a motor vehicle, comprising:
generating a negative pressure in a gas compartment or headspace of the fuel tank;
applying the negative pressure to the liquid trap through a suction line, said liquid trap having a collection container collecting liquid fuel during venting of the fuel tank, said suction line branching into a plurality of parallel branch lines with smaller line cross sections before entering the collection container, said branch lines entering the collection container through a bottom of the collection container, wherein end sections of the branch lines extend in the collection container upwards and have lateral apertures for passage of liquid fuel therethrough into the branch lines; and
at least partially suctioning the liquid fuel located in the collection container through the suction line into the gas compartment or headspace.

2. The method of claim 1 , wherein the negative pressure in the gas compartment or headspace is generated as a result of cooling of the fuel tank, with the fuel tank being closed gas-tight.

3. The method of claim 1 , wherein the negative pressure in the gas compartment or headspace is generated as a result of consumption of fuel in an internal combustion engine of the motor vehicle, with the fuel tank being closed gas-tight.

4. The method of claim 1 , wherein the negative pressure in the gas compartment or headspace is generated by suctioning gas or a gas mixture from the gas compartment or headspace, with the fuel tank being gas-tightly closed.

5. The method of claim 4 , wherein the gas or gas mixture is suctioned into an intake tract of an internal combustion engine of the motor vehicle.

6. The method of claim 1 , further comprising supporting the suctioning of the liquid fuel from the liquid trap by opening a closed tank shutoff or isolating valve.

7. A fuel system for a motor vehicle, comprising:
a fuel tank having a gas compartment or headspace; and
a liquid fuel trap situated within the fuel tank for separation of liquid fuel during venting of the fuel tank, said liquid trap comprising a collection container for collection of the liquid fuel separated by the liquid trap, said gas compartment or headspace of the fuel tank being connected to the liquid fuel trap by a suction line which communicates with the collection containers, said suction line branching into a plurality of parallel branch lines with smaller line cross sections before entering the collection container, said branch lines entering the collection container through a bottom of the collection container, wherein end sections of the branch lines extend in the collection container upwards and have lateral apertures for passage of liquid fuel therethrough into the branch lines.

8. The fuel system of claim 7 , wherein an end of the suction line is situated in the gas compartment or headspace and is provided with a tank vent valve and filling level limitation valve.

9. The fuel system of claim 7 , wherein the liquid trap is connected to an activated carbon filter through a vent line, said vent line containing an expansion volume and/or a tank shutoff or isolating valve for preventing a pressure increase in the collection container.

10. The fuel system of claim 7 , further comprising an automatically operating valve arranged between the liquid trap and a filler plug or filler tube of the fuel tank, said automatically operating valve comprising a first port communicating with the liquid trap, a second port communicating with the filler plug or filler tube, and a third port communicating with an environment of the motor vehicle.

11. The fuel system of the claim 7 , further comprising a further suction line between the gas compartment or headspace of the fuel tank and an intake tract of a combustion engine of the motor vehicle, said further suction line comprising a shutoff valve.

Assignees

• Audi Ag

Inventors

• Hagen Harald

Classifications

• B60K2015/03509

  with a droplet separator in the vent line · CPC title

• B60K15/03504

  adapted to avoid loss of fuel or fuel vapour, e.g. with vapour recovery systems · CPC title

• B60K2015/03514

  with vapor recovery means · CPC title

• F02M33/04

  returning to the intake passage · CPC title

• F02M33/08 Primary

  returning to the fuel tank · CPC title