Exhaust gas system for a motor vehicle, method for operating an exhaust gas system, and motor vehicle

Abstract

An exhaust gas system for a motor vehicle includes an exhaust gas burner and a pressure sensor for sensing flame formation in the exhaust gas burner.

Claims

1. An exhaust gas system for a motor vehicle, said exhaust gas system comprising: an engine exhaust gas path through which combustion products are delivered from an engine of the motor vehicle; an exhaust gas burner and a pressure sensor for sensing flame formation in the exhaust gas burner; a burner exhaust gas path connecting the exhaust gas burner with the engine exhaust gas path, the burner exhaust gas path intersecting the engine exhaust gas path at an intersection point; a supply air path for introducing combustion air into the exhaust gas burner, the pressure sensor being arranged in the supply air path and outside of a combustion chamber of the exhaust gas burner; a further pressure sensor being arranged in the burner exhaust gas path, the pressure sensor and the further pressure sensor being configured to determine a differential pressure between the supply air path and the burner exhaust gas path, wherein the pressure sensor and the further pressure sensor are both arranged upstream of the intersection point.

2. The exhaust gas system according to claim 1, wherein the exhaust gas system comprises an optical sensor arranged in the combustion chamber.

3. The exhaust gas system according to claim 1, wherein the supply air path comprises an air pump for conveying air into the exhaust gas burner, the pressure sensor being arranged between the air pump and the exhaust gas burner, the pressure sensor being arranged between the air pump and a valve of the supply air path.

4. The exhaust gas system according to claim 1, wherein the pressure sensor is a dual sensor for sensing pressure and temperature.

5. The exhaust gas system according claim 1 further comprising a temperature sensor for sensing an exhaust gas temperature of the exhaust gas burner.

6. The exhaust gas system according to claim 5, wherein the temperature sensor is arranged in the burner exhaust gas path at a location between the further pressure sensor and the exhaust gas burner.

7. A motor vehicle comprising the exhaust gas system according to claim 1.

8. The exhaust gas system according to claim 1, further comprising a first catalytic converter positioned upstream of the intersection point.

9. The exhaust gas system according to claim 8, further comprising a second catalytic converter positioned downstream of the intersection point.

10. The exhaust gas system according to claim 9, further comprising a filter positioned downstream of the second catalytic converter.

11. The exhaust gas system according to claim 1, wherein the further pressure sensor is exposed to pressures within the burner exhaust gas path and the engine exhaust gas path.

12. The exhaust gas system according to claim 1, further comprising a non-return valve arranged in the supply air path at a location between the pressure sensor and the exhaust gas burner.

13. A method for operating an exhaust gas system of a motor vehicle, said method comprising: delivering engine combustion products produced by an engine of the motor vehicle through an engine exhaust gas path; delivering combustion air through a supply air path and to an exhaust gas burner of the exhaust gas system, delivering burner combustion products produced by the exhaust gas burner through a burner exhaust gas path that connects the exhaust gas burner with the engine exhaust gas path, wherein the burner exhaust gas path intersects the engine exhaust gas path at an intersection point; and determining a differential pressure between the supply air path and the burner exhaust gas path using both a pressure sensor positioned within the air supply path and a further pressure sensor positioned within the burner exhaust gas path to sense flame formation in the exhaust gas burner, wherein the pressure sensor and the further pressure sensor are both arranged upstream of the intersection point.

14. The method according to claim 13, further comprising sensing flame formation: (i) optically inside of a combustion chamber of the exhaust gas burner, and/or (ii) via a temperature difference between air flowing into the exhaust gas burner and exhaust gas flowing out of the exhaust gas burner, and/or (iii) acoustically using a knock sensor of the motor vehicle.

15. The method according to claim 13, further comprising sensing flame formation optically inside of a combustion chamber of the exhaust gas burner.

16. The method according to claim 13, further comprising sensing flame formation via a temperature difference between air flowing into the exhaust gas burner and exhaust gas flowing out of the exhaust gas burner.

17. The method according to claim 13, further comprising sensing flame formation acoustically using a knock sensor of the motor vehicle.

18. The method according to claim 13, further comprising sensing flame formation: (i) optically inside of a combustion chamber of the exhaust gas burner, (ii) via a temperature difference between air flowing into the exhaust gas burner and exhaust gas flowing out of the exhaust gas burner, and (iii) acoustically using a knock sensor of the motor vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details, features and advantages of the invention can be found in the drawings and in the following description of preferred embodiments with reference to the drawings. The drawings merely illustrate exemplary embodiments of the invention which do not restrict the concept of the invention.

(2) FIG. 1 is a schematic view of an exhaust gas system according to an exemplary embodiment of the present invention.

(3) FIG. 2 is a schematic view of a motor vehicle according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 is a schematic view of an exhaust gas system 1 according to an exemplary embodiment of the present invention. The exhaust gas system 1 discharges exhaust gases from an internal combustion engine 13 of a motor vehicle and purifies these gases in a first catalytic converter 14, a second catalytic converter 15 and a particulate filter 16.

(5) In order to bring the second catalytic converter 15 and the particulate filter 16 to a specific temperature quickly and precisely, for example after a cold start, the exhaust gas system 1 comprises an exhaust gas burner 2. Fuel and combustion air are fed into a combustion chamber 5 of the exhaust gas burner 2 via a fuel line 17 and a supply air path 4, respectively. The mixture of combustion air and fuel is then ignited and combusted in the combustion chamber 5. The resulting hot exhaust gases are conducted via an exhaust gas path 6 to the second catalytic converter 15 and to the particulate filter 16 and heat them.

(6) In order to precisely control the exhaust gas system 1, it is essential that the combustion, in particular the flame formation, in the exhaust gas burner 2 is monitored. For this purpose, the exhaust gas system 1 comprises a pressure sensor 3. The pressure sensor 3 is arranged in the supply air path 4 and is spaced so far apart from the exhaust gas burner 2 that the pressure sensor 3 is protected from heat generated in the combustion chamber 5. If the mixture of combustion air and fuel ignites in the combustion chamber 5 and a flame is formed in the process, this can be recorded by the pressure sensor 3 as a result of the change in pressure.

(7) In addition to the pressure sensor 3, the supply air path 4 comprises an air filter 12 for purifying the combustion air, an air pump 8 for generating an air flow toward the exhaust gas burner 2, and a valve 9. The pressure sensor 3 is arranged between the air pump 8 and the valve 9, which is designed as a non-return valve. As a result, the pressure sensor 3 is able to record the pressure change caused by the flame formation.

(8) A further pressure sensor 3′ is arranged in the exhaust gas path 6 of the exhaust gas burner 2. Together with the pressure sensor 3, a differential pressure across the exhaust gas burner 2 can therefore be determined. This also allows the flame formation in the combustion chamber 5 to be sensed in a highly accurate manner.

(9) Furthermore, the exhaust gas path 6 comprises a temperature sensor 10 for measuring the temperature of the exhaust gas from the exhaust gas burner 2. The pressure sensor 3 is preferably designed as a dual sensor for determining pressure and temperature. By determining the temperature in the supply air path 4 and the temperature of the exhaust gas of the exhaust gas burner 2, the formation of flames can also be inferred using the pressure sensor 3 and the temperature sensor 10, and the pressure-based sensing of the flame formation can thus be checked. The exhaust gas burner 2 in the combustion chamber 5 also comprises an optical sensor 7 to check the pressure-assisted sensing of the flame formation. The formation of flames can also be inferred acoustically using a knock sensor (see FIG. 2) of the motor vehicle.

(10) FIG. 2 is a schematic view of a motor vehicle 100 according to an exemplary embodiment of the present invention. The motor vehicle 100 comprises an internal combustion engine 13 and an exhaust gas system 1 according to an exemplary embodiment of the present invention. The sensing of the flame formation in the exhaust gas burner of the exhaust gas system 1 is checked acoustically by means of a knock sensor 11.

LIST OF REFERENCE SIGNS

(11) 1 exhaust gas system 2 exhaust gas burner 3 pressure sensor 3′ further pressure sensor 4 supply air path 5 combustion chamber 6 exhaust gas path 7 optical sensor 8 air pump 9 valve 10 temperature sensor 11 knock sensor 12 air filter 13 internal combustion engine 14 first catalytic converter 15 second catalytic converter 16 particulate filter 17 fuel line 100 motor vehicle