Combustion chamber assembly unit

1. A combustion chamber assembly unit for a fuel-operated vehicle heater, the combustion chamber assembly unit comprising:

a combustion chamber housing elongated in a direction of a housing longitudinal axis, the combustion chamber housing comprising a combustion chamber circumferential wall delimiting a combustion in a radial direction and a combustion chamber bottom axially delimiting the combustion chamber;

a combustion air feed volume open to the combustion chamber via a plurality of passage openings in the combustion chamber housing; and

a cooling medium feed device for feeding a liquid cooling medium to the combustion air feed volume.

2. A combustion chamber assembly unit in accordance with claim 1 , further comprising an outer circumferential wall surrounding the combustion chamber circumferential wall on an outside, wherein:

the combustion chamber circumferential wall cooperates with the combustion chamber circumferential wall to form a combustion air feed chamber of the combustion air feed, between the combustion chamber circumferential wall and the outer circumferential wall; and

the combustion air feed chamber is open to the combustion chamber over at least some of the passage openings; and

the cooling medium feed device comprises at least one cooling medium feed line for releasing liquid cooling medium into the combustion air feed chamber.

3. A combustion chamber assembly unit in accordance with claim 2 , wherein the at least one cooling medium feed line opens into the combustion air feed chamber.

4. A combustion chamber assembly unit in accordance with claim 2 , wherein the cooling medium feed line has at least one cooling medium release opening, which is open to the combustion air feed chamber.

5. A combustion chamber assembly unit in accordance with claim 4 , wherein the cooling medium feed device further comprises a cooling medium release nozzle with the at least one cooling medium release opening at one end of a line section of the cooling medium feed line, which line section extends into the combustion air feed chamber.

6. A combustion chamber assembly unit in accordance with claim 5 , wherein the line section extends essentially in a direction of the housing longitudinal axis.

7. A combustion chamber assembly unit in accordance with claim 4 , wherein:

the combustion air feed chamber surrounds the combustion chamber radially outside, in at least some areas; and

the cooling medium feed line comprises a line section extending in the combustion air feed chamber around the combustion chamber circumferential wall in a circumferential direction in at least some areas;

the at least one cooling medium release opening is provided in the line section.

8. A combustion chamber assembly unit in accordance with claim 7 , wherein:

the at least one cooling medium release opening comprises a plurality of cooling medium release openings; and

the plurality of cooling medium release openings are arranged along the line section, following one another in the circumferential direction.

9. A combustion chamber assembly unit in accordance with claim 7 , wherein:

the at least one cooling medium release opening is provided on a side of the line section that axially faces the combustion chamber bottom; or

the at least one cooling medium release opening is provided on a side of the line section that faces axially away from the combustion chamber bottom.

10. A combustion chamber assembly unit in accordance with claim 1 , wherein the cooling medium feed device further comprises a cooling medium pump and a cooling medium reservoir, the cooling medium pump delivering the liquid cooling medium from the cooling medium reservoir to the combustion air feed volume.

11. A combustion chamber assembly unit in accordance with claim 1 , wherein the combustion chamber bottom comprises porous evaporator medium and a fuel feed line guiding liquid fuel to the porous evaporator medium.

12. A vehicle heater comprising a combustion chamber assembly unit, the combustion chamber assembly unit comprising:

a combustion chamber housing elongated in a direction of a housing longitudinal axis, the combustion chamber housing comprising a combustion chamber circumferential wall delimiting a combustion in a radial direction and a combustion chamber bottom axially delimiting the combustion chamber;

a combustion air feed volume open to the combustion chamber via a plurality of passage openings in the combustion chamber housing; and

a cooling medium feed device for feeding a liquid cooling medium to the combustion air feed volume.

13. A vehicle heater in accordance with claim 12 , further comprising:

at least one waste gas flow volume; and

a reduction catalytic converter device provided in the waste gas flow volume, wherein the cooling medium feed device is configured to feed a reducing agent as the liquid cooling medium.

14. A vehicle heater in accordance with claim 13 , further comprising a heat exchanger housing, wherein:

the at least one a waste gas flow space, providing the at least a part of the gas flow volume is formed between the combustion chamber assembly unit and a heat exchanger housing; and

the reduction catalytic converter device is arranged in the waste gas flow space.

15. A vehicle heater in accordance with claim 13 , wherein further comprising an oxidation catalytic converter device provided in the waste gas flow volume.

16. A vehicle heater in accordance with claim 15 , wherein the reduction catalytic converter device is integrated into the oxidation catalytic converter device.

17. A vehicle heater in accordance with claim 14 , wherein the combustion chamber assembly unit further comprising an outer circumferential wall surrounding the combustion chamber circumferential wall on an outside, wherein:

the combustion chamber circumferential wall cooperates with the combustion chamber circumferential wall to form a combustion air feed chamber of the combustion air feed, between the combustion chamber circumferential wall and the outer circumferential wall; and

the combustion air feed chamber is open to the combustion chamber over at least some of the passage openings; and

the cooling medium feed device comprises at least one cooling medium feed line for releasing liquid cooling medium into the combustion air feed chamber.

18. A vehicle heater in accordance with claim 17 , wherein the cooling medium feed device further comprises a cooling medium release nozzle with the at least one cooling medium release opening at one end of a line section of the cooling medium feed line, which line section extends into the combustion air feed chamber and is open to the combustion air feed chamber.

19. A vehicle heater in accordance with claim 17 , wherein:

the cooling medium feed line has at least one cooling medium release opening, which is open to the combustion air feed chamber

the combustion air feed chamber surrounds the combustion chamber radially outside, in at least some areas;

the cooling medium feed line comprises a line section extending in the combustion air feed chamber around the combustion chamber circumferential wall in a circumferential direction in at least some areas; and

the at least one cooling medium release opening is provided in the line section.

20. A vehicle heater in accordance with claim 17 , wherein the cooling medium feed device further comprises a cooling medium pump and a cooling medium reservoir, the cooling medium pump delivering the liquid cooling medium from the cooling medium reservoir to the combustion air feed volume.