Tank system for a motor vehicle having a volume modifying element

Patent metadata

Field	Value
Publication number	US-10675967-B2
Application number	US-201615372470-A
Country	US
Kind code	B2
Filing date	Dec 8, 2016
Priority date	Jul 21, 2014
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A tank system of a motor vehicle includes a volume modifying element, having a compensation volume, which is provided in the inner chamber of the fuel tank and which is used to equalize the vapor pressure. The compensation volume is connected to the surrounding area. The only connection between the volume modifying element and the surrounding area is formed by a storage unit of the gaseous fuel components and the inner chamber of the fuel tank is connected to the surrounding area by a valve unit. The valve unit is normally open when filling the fuel tank and when exceeding or falling below the pressure limits in the inner chamber of the tank, and is otherwise closed. The storage unit is connected to the valve unit. The volume modifying element and the valve unit are designed in such a way that vehicles which are parked for several days do not undergo diurnal losses due to changes in temperature of the surroundings, due to the fact that the vapor pressure equilibrium in the fuel tank can be maintained by the automatic supply and removal of ambient air in the, or from the, volume modifying element as long as the valve unit remains closed.

First claim

What is claimed is:

1. A tank system of a motor vehicle, comprising:
a fuel tank having an inner chamber;
a volume modifying element provided in the inner chamber of the fuel tank, wherein a compensation volume of the volume modifying element is connected to surroundings of the motor vehicle depending on boundary conditions;
a valve unit connecting the inner chamber of the fuel tank with the surroundings, wherein
the valve unit is normally open when the fuel tank is being filled as well as when an overpressure limit value in a magnitude of up to 100 mbar is exceeded and when the overpressure limit value falls below a specific negative pressure limit value of an amount not above the overpressure limit value between a pressure in the inner chamber of the tank and a surrounding pressure, and the valve unit is otherwise closed;

a first storage unit for gaseous fuel components and a second storage unit for gaseous fuel components, the second storage unit being arranged downstream of the first storage unit in a direction of the surroundings;
a tank ventilation line leading from the inner chamber of the fuel tank through the valve unit to the first storage unit for gaseous fuel components, and extending from the first storage unit into the second storage unit for gaseous fuel components; and
a ventilation line for the compensation volume of the volume modifying element extending only into:
the tank ventilation line between the first and second storage unit,
(ii) the first storage unit, or
(iii) the tank ventilation line upstream of the first storage unit and downstream of the valve unit.

2. The tank system according to claim 1 , wherein
the volume modifying element and the valve unit are configured such that when a motor vehicle is parked for an extended period, no diurnal losses are created due to changes in ambient temperature in that vapor pressure equilibrium is maintained by independent intake and removal of ambient air into or from the volume modifying element to an extent that the valve unit remains close.

3. The tank system according to claim 1 , wherein
a maximum capacity of the compensation volume of the volume modifying element is in a magnitude of 25% to 40% of the inner chamber of the fuel tank.

4. The tank system according to claim 1 , wherein
the volume modifying element is configured as a deformable bubble or bag, which either completely or in cooperation with a section of an inner wall of the fuel tank forms the compensation volume, the compensation volume being modifiable and connected to the surroundings.

5. The tank system according to claim 1 , further comprising:
a slosh protection wall provided in the fuel tank, wherein
the slosh protection wall at least partially encloses the volume modifying element in a maximum state of expansion and has through-openings for fuel.

6. The tank system according to claim 1 , further comprising:
a measuring device for a fuel filling level in the fuel tank, the measuring device operating as a level sensor; and
an electronic evaluation unit of the level sensor being configured to take into account a negative pressure in the fuel tank, if applicable.

7. The tank system according to claim 1 , wherein
the volume modifying element is configured to unfold automatically for a volume enlargement and to fold up automatically for a volume reduction.

8. The tank system according to claim 1 , wherein:
the second storage unit, as well as the first storage unit, contains an activated carbon, but with different storage properties.

9. The tank system according to claim 1 , wherein the second storage unit is formed so as to be smaller than the first storage unit.

10. The tank system according to claim 9 , wherein the second storage unit is a honeycomb or low bleed emission activated carbon filter.

11. The tank system according to claim 10 , wherein the valve unit is a negative pressure tank lock valve.

12. The tank system according to claim 1 , wherein:
the first storage unit is provided for refueling and/or for high tank pressure values when operating the motor vehicle.

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Arras Emmanuel
• Pribil Jutta
• Huber Markus

Classifications

• B60K2015/03085

  using inflatable bags or bladders in the tanks · CPC title

• F02M25/0836

  Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold · CPC title

• B60K2015/0775

  for reducing movement or slash noise of fuel · CPC title

• F02M25/089

  Layout of the fuel vapour installation · CPC title

• B60K2015/03217

  Fuel level sensors · CPC title