System, in particular for a motor vehicle or utility vehicle, and method for the same

Patent metadata

Field	Value
Publication number	US-11094948-B2
Application number	US-201515126124-A
Country	US
Kind code	B2
Filing date	Jan 29, 2015
Priority date	Mar 17, 2014
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

The invention relates to a system ( 10 ) for storing natural gas as fuel, in particular for a motor vehicle or utility vehicle, wherein the system ( 10 ) has at least one storage tank ( 11 ) for the fuel. It is provided according to the invention that the storage tank ( 11 ) is assigned at least one fuel cell ( 12 ), wherein natural gas that has changed into the gaseous state can be fed from the storage tank ( 11 ) to the fuel cell ( 12 ) in order to be at least partially converted into electrical energy, wherein the storage tank ( 11 ) and the fuel cell ( 12 ) interact by way of a control unit ( 13 ). In this case, the fuel cell ( 12 ) is in the form of a solid oxide fuel cell.

First claim

The invention claimed is:

1. A system for storing natural gas as fuel, the system comprising an internal combustion engine ( 30 ), at least one storage tank for the fuel, and at least one fuel cell ( 12 ), wherein the system is configured such that natural gas that has changed into a gaseous state can be fed from the storage tank ( 11 ) to the fuel cell ( 12 ) in order to be at least partially converted into electrical energy, wherein the system also comprises at least one flow path ( 14 , 14 ′, 25 ) configured to operatively connect the fuel cell ( 12 ) in terms of fluid mechanics to the storage tank ( 11 ), and at least one return flow path ( 25 ) configured to return natural gas escaping in excess from the fuel cell ( 12 ) to the storage tank ( 11 ), the system further including at least one valve ( 16 , 17 ) disposed in the at least one flow path ( 14 , 14 ′, 25 ), a control unit ( 13 ) for controlling the at least one valve ( 16 , 17 ) and the fuel cell ( 12 ), and at least one pressure sensor assigned to the storage tank ( 11 ) to continually detect a pressure produced in the storage tank ( 11 ) by the natural gas,
wherein the control unit ( 13 ) acquires pressure measurement values that are detected by the pressure sensor and signaled to the control unit ( 13 ), and
wherein, when the internal combustion engine ( 30 ) of the system is turned off, the control unit ( 13 ) controls the at least one fuel cell ( 12 ) and the at least one valve ( 16 , 17 ) as a function of the pressure in the storage tank ( 11 ) such that the control unit ( 13 ) only opens the flow path ( 14 , 14 ′) to the fuel cell ( 12 ) and activates the fuel cell ( 12 ) when the pressure in the storage tank ( 11 ) achieves or exceeds a predetermined pressure threshold value that is a function of a burst pressure of the storage tank, thereby relieving over-pressure in the storage tank ( 11 ).

2. The system according to claim 1 , wherein the control unit ( 13 ) is electrically operatively connected to the at least one valve via a signal line.

3. The system according to claim 2 , wherein a further signal line of the control unit ( 13 ) is connected to the fuel cell ( 12 ).

4. The system according to claim 1 , characterized in that a second flow path ( 14 ) is provided for a combustion chamber of an internal combustion engine ( 30 ) in order to supply the combustion chamber with natural gas from the storage tank ( 11 ) at least during a driving mode of the internal combustion engine.

5. The system according to claim 1 , characterized in that the fuel cell ( 12 ) is in the form of a solid oxide fuel cell.

6. A method for operating the system according to claim 1 , the method comprising the following steps:
acquiring ( 120 ) a temporally dependent pressure that is in each case currently prevailing in the storage tank ( 11 ), and
supplying ( 140 ) natural gas present in the vapor state from the storage tank ( 11 ) to the fuel cell ( 12 ) and activating the fuel cell ( 12 ) only when the acquired pressure in the storage tank ( 11 ) reaches or exceeds the predetermined pressure threshold value that is a function of the burst pressure of the storage tank, thereby relieving over-pressure in the storage tank ( 11 ),
wherein, in an activated state of the fuel cell, natural gas that has moved in excess to a cathode side of the fuel cell ( 12 ) is returned to the storage tank ( 11 ).

7. A motor vehicle comprising a system according to claim 1 .

Assignees

• Bosch Gmbh Robert

Inventors

• Wach Achim

Classifications

• B60L58/31

  for starting of fuel cells · CPC title

• B60L58/34

  by heating · CPC title

• Y02T90/40

  Application of hydrogen technology to transportation, e.g. using fuel cells · CPC title

• H01M8/04201 Primary

  Reactant storage and supply, e.g. means for feeding, pipes · CPC title

• H01M8/04425

  at auxiliary devices, e.g. reformers, compressors, burners · CPC title