Claims
- 1. A method for catalytic aftertreatment of exhaust gas of an internal-combustion engine, comprising:
providing first and second spatially separate catalyst devices in an exhaust gas system, the first catalyst device being arranged in a position close to the engine, and the second catalyst device being arranged in a position away from the engine, and causing a heating measure which has an exothermal reaction for heating the second catalyst device to take place.
- 2. The method according to claim 1, wherein the heating measure has a first phase in which the exothermal reaction heats the second catalyst device above the light-off temperature.
- 3. The method according to claim 2, wherein the heating measure has a second phase without the exothermal reaction for cooling to the light-off temperature, the engine being operated stoichiometrically or in a lean fashion.
- 4. The method according to claim 1, wherein a mixture is adjusted such that the exhaust gas coming from the engine has combustible constituents, and wherein air is supplied to the exhaust gas with the combustible constituents in the exhaust gas system in order to obtain a combustible mixture.
- 5. The method according to claim 4, wherein the air is fed at a position upstream of the first catalyst device.
- 6. The method according to claim 4, wherein the air is fed at a position downstream of the first catalyst device.
- 7. The method according to claim 5, wherein at least two bends are provided in a flow of the exhaust gas between the position at which the air is fed and a position at which the exothermal reaction takes place.
- 8. The method according to claim 1, wherein a reaction chamber is set up in front of the second catalyst device, and further comprising initiating the exothermal reaction in the reaction chamber by an ignition device.
- 9. The method according to claim 8, wherein the ignition device is arranged essentially centrally in the reaction chamber.
- 10. The method according to claim 1, wherein the second catalyst device is provided with a multi-constituent integral coating which has a catalytic constituent and an adsorbing constituent for hydrocarbons.
- 11. The method according to claim 1, and further comprising providing a third catalyst device upstream directly in front of a reaction chamber of the second catalyst device.
- 12. The method according to claim 11, wherein the third catalyst device is provided with a multi-constituent integral coating which has a catalytic constituent and an adsorbing constituent for hydrocarbons.
- 13. The method according to claim 6, wherein at least two bends are provided in a flow of the exhaust gas between the position at which the air is fed and a position at which the exothermal reaction takes place.
- 14. The method according to claim 8, wherein said ignition device is a glow device.
- 15. A system for catalytic aftertreatment of exhaust gas of an internal-combustion engine, comprising:
first and second spatially separate catalyst devices, the first catalyst device being arranged in a position close to the engine, and the second catalyst device being arranged in a position away from the engine, and a reaction chamber arranged in front of the second catalyst device for causing an exothermal reaction to take place for heating the second catalyst device.
- 16. The system according to claim 15, and further comprising a control device which causes the exothermal reaction for heating the second catalyst device during a warm-up phase until the first catalyst device has reached its light-off temperature.
- 17. The system according to claim 15, wherein a feeding device is provided for feeding air at a position upstream of the first catalyst device.
- 18. The system according to claim 15, wherein a feeding device is provided for feeding air at a position downstream of the first catalyst device.
- 19. The system according to claim 17, wherein the feeding device has a pipe which extends into an exhaust pipe and which has a slotted pipe shell.
- 20. The system according to claim 19, wherein the pipe which extends into the exhaust pipe is arranged essentially perpendicular to the flow direction of the exhaust gas.
- 21. The system according to claim 15, and further comprising an ignition device provided in the reaction chamber.
- 22. The system according to claim 21, wherein the ignition device is essentially arranged centrally in the reaction chamber.
- 23. The system according to claim 15, wherein the second catalyst device is provided with a multi-constituent integral coating which has a catalytic constituent and an adsorbing constituent for hydrocarbons.
- 24. The system according to claim 15, and further comprising a third catalyst device provided upstream directly in front of the reaction chamber of the second catalyst device.
- 25. The system according to claim 17, wherein at least two bends are provided in exhaust gas flow between the feeding device and the reaction chamber.
- 26. The system according to claim 15, wherein the reaction chamber has a cylindrical construction.
- 27. The system according to claim 18, wherein the feeding device has a pipe which extends into an exhaust pipe and which has a slotted pipe shell.
- 28. The system according to claim 25, wherein the pipe which extends into the exhaust pipe is arranged essentially perpendicular to the flow direction of the exhaust gas.
- 29. The system according to claim 18, wherein at least two bends are provided in exhaust gas flow between the feeding device and the reaction chamber.
Priority Claims (1)
Number |
Date |
Country |
Kind |
100 38 724.1 |
Aug 2000 |
DE |
|
Parent Case Info
[0001] This application claims the priority of German application 100 38 724.1, filed Aug. 9, 2000, the disclosure of which is expressly incorporated by reference herein.