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

Abstract

An exhaust system includes at least one exhaust gas purification component, at least one exhaust line, at least one connecting device for connecting the exhaust system to an internal combustion engine of a motor vehicle and at least one fastening element for additionally fastening the exhaust system to the motor vehicle. The purification component can oscillate at a first resonance frequency range of less than 150 Hz in a fastened state. The purification component can oscillate due to vibrations of the engine at least when the engine is started or switched off. This, in particular, allows ash residues to be removed from a purification component during starting of the motor vehicle, so that maintenance expense for the purification component is reduced and effective operation thereof is possible over the long term. A motor vehicle having an exhaust system and a method for operating the motor vehicle are also provided.

Claims

1. An exhaust system, comprising: at least one exhaust-gas purification component; at least one exhaust line connected to said at least one exhaust-gas purification component; at least one connector configured to connect said at least one exhaust line to an internal combustion engine of a motor vehicle; and at least one fastener configured to additionally fasten the exhaust system to the motor vehicle; in an installed state of the exhaust system in the motor vehicle, mechanical properties of said at least one exhaust-gas purification component, said at least one exhaust line, said connector and said at least one fastener being coordinated with one another for setting a first resonance frequency range of said at least one exhaust-gas purification component between 50 to 300 Hz for freeing said at least one exhaust-gas purification component from particles.

2. The exhaust system according to claim 1, wherein said at least one exhaust-gas purification component is configured to be stimulated to perform oscillations with the first resonance frequency range by vibrations of the internal combustion engine at least during start-up or shut-down of the internal combustion engine.

3. The exhaust system according to claim 1, wherein at least two of the following components have a construction permitting said components to attain resonance frequencies from the first resonance frequency range: said at least one connector, said at least one fastener, said at least one exhaust-gas purification component, or said at least one exhaust line.

4. The exhaust system according to claim 1, wherein said at least one exhaust-gas purification component has at least one part having a second resonance frequency range of higher than 500 Hz.

5. The exhaust system according to claim 4, which further comprises a vibrator associated with said at least one exhaust-gas purification component and configured to stimulate said at least one exhaust-gas purification component to perform oscillations with a frequency in the second resonance frequency range.

6. The exhaust system according to claim 1, wherein said at least one exhaust line is one exhaust line extending in a single direction and being connected to said at least one exhaust-gas purification component.

7. The exhaust system according to claim 1, wherein said at least one exhaust-gas purification component includes channels delimited by filter material being permeable to exhaust gas.

8. A motor vehicle, comprising: an internal combustion engine; and an exhaust system connected to said internal combustion engine, said exhaust system including: at least one exhaust-gas purification component; an exhaust line extending between and being connected to said internal combustion engine and said at least one exhaust-gas purification component; at least one connector configured to connect the exhaust system to said internal combustion engine; and at least one fastener configured to additionally fasten the exhaust system to the motor vehicle; in an installed state of the exhaust system in the motor vehicle, mechanical properties of said at least one exhaust-gas purification component, said at least one exhaust line, said connector and said at least one fastener being coordinated with one another for setting a first resonance frequency range of said at least one exhaust-gas purification component between 50 to 300 Hz for allowing said internal combustion engine to free particles from said at least one exhaust-gas purification component during idling of said internal combustion engine.

9. The motor vehicle according to claim 8, wherein said at least one exhaust-gas purification component includes channels delimited by filter material being permeable to exhaust gas, and said exhaust line is one exhaust line extending in a single direction.

10. A method for operating a motor vehicle having an internal combustion engine and an exhaust system, the method comprising the following steps: providing at least one exhaust line; connecting an internal combustion engine to one end of the at least one exhaust line; connecting an exhaust-gas purification component along the at least one exhaust line; connecting at least one connector and at least one fastener configured for fastening the at least one exhaust line to the motor vehicle; and during a starting process, vibrating the internal combustion engine with the exhaust-gas purification component, the at least one exhaust line, the at least one connector, and the at least one fastener being coordinated with one another for generating a first resonance frequency range between 50 to 150 Hz in the exhaust-gas purification component for a length of time, and freeing the exhaust-gas purification component from particles.

11. The method according to claim 10, wherein the exhaust-gas purification component includes channels delimited by filter material being permeable to exhaust gas, and the at least one exhaust line is one exhaust line extending in a single direction.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a block diagram of a motor vehicle having an exhaust system according to the invention; and

(2) FIG. 2 is a fragmentary, diagrammatic, longitudinal-sectional view of an exhaust-gas purification component.

DETAILED DESCRIPTION OF THE INVENTION

(3) Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a motor vehicle 6 having an internal combustion engine 5 and an exhaust system 1. The exhaust system 1 has an exhaust line 3 with two (integrated) exhaust-gas purification or treatment components 2, a connector or connection device 4 and two fasteners or fastening elements 7. The exhaust system 1 is connected by the connection device 4 to the internal combustion engine 5 and is additionally connected by the fastening elements 7 to the motor vehicle 6. Detectors 17, which are also disposed on the exhaust line 3, are connected through data lines 18 to a control unit 19. A vibrator or vibration element 9, which is also associated with one of the exhaust-gas purification components 2, is likewise connected through the data line 18 to the control unit 19. The control unit 19 is furthermore connected to the internal combustion engine 5.

(4) The mechanical properties of the exhaust-gas purification component 2, of the exhaust line 3, of the connection device 4 and of the fastening element 7, are coordinated with one another in such a way that at least one exhaust-gas purification component 2 has a first resonance frequency range of below 300 Hz or even below 150 Hz, but above 50 Hz. It is ensured in this way that, during the starting of the internal combustion engine 5, as a result of transmitting the vibrations of the internal combustion engine 5 to the exhaust system 1, the at least one exhaust-gas purification component 2 is stimulated to perform oscillations or excited to oscillate, in such a way that particles deposited in the exhaust-gas purification component 2 are detached. A stimulation of oscillations as a result of uneven road surfaces during a journey is, however, prevented. A stimulation of the exhaust-gas purification component 2 to perform oscillations while the internal combustion engine 5 is at idle and/or under load can thus likewise practically be prevented (if desired). During the starting of the internal combustion engine 5, the control unit 19 controls injection processes in such a way that preferably oscillations with frequencies from a first resonance frequency range are stimulated.

(5) The detectors 17 determine parameters of the exhaust gas, such as pressure, temperature and/or exhaust-gas composition, in the exhaust line 3 and transmit these to the control unit 19. The control unit 19 can, after predefined intervals and/or in the presence of predefinable parameters of the internal combustion engine 5 and/or in the presence of predefinable parameters of the exhaust gas, transmit a signal for performing vibrations to the vibration element 9. The vibration element 9 performs, in particular, oscillations with frequencies higher than 500 Hz [1/sec]. The frequency of the stimulating oscillation can thus be set in such a way that the exhaust-gas purification component 2 is stimulated with a frequency in a second resonance frequency range of parts 8 of the exhaust-gas purification component 2 shown in FIG. 2. The exhaust-gas purification component 2 may be stimulated in an alternating manner with different frequencies by the vibration element 9. In this case, the stimulating amplitude of the vibration element 9 is preferably less than 1 mm. In this case, the vibration of the exhaust-gas purification component 2 is performed during the operation of the internal combustion engine 5, in such a way that particles which have been deposited in the exhaust-gas purification component 2 and which have not been converted during a regeneration are detached and entrained by the exhaust-gas flow of the internal combustion engine. The vibration element 9 may, for example, be a piezoelectric element or an electric motor.

(6) FIG. 2 shows a portion of an exhaust-gas purification component 2. The exhaust-gas purification component 2 has channels 11 into which the exhaust gas flows in an original flow direction 16. The channels 11 are formed by channel walls 13 which have passages 15 and which are formed partially by filter material 12. Furthermore, the channel walls 13 may have structures 14 (for example corrugated metal foils) which divert the exhaust gas. Arrows indicate the flow direction of the exhaust gas. The exhaust gas carries particles 10 with it and is diverted by the structures 14 in such a way that the particles 10 can be deposited in the filter material 12. In general, during the regeneration of the exhaust-gas purification component 2, soot particles and ash are converted into carbon dioxide and nitrogen. A situation may, however, arise in which the conversion does not take place completely, and as a result, the filter material 12 and/or the passages 15 become blocked. Such a blockage may possibly increase the pressure drop across the exhaust-gas purification component 2. As a result of the stimulation of the exhaust-gas purification component 2 to perform vibrations during the starting or shut-down of the internal combustion engine 5, the deposited particles 10 can detach and pass back into the exhaust-gas flow. A blockage of the exhaust-gas purification component 2 is thus prevented in an effective manner.

(7) The present invention permits, in particular, the removal of ash residues from an exhaust-gas purification component 2 during the starting of the motor vehicle 6, in such a way that the maintenance expenditure for such an exhaust-gas purification component is reduced and long-term effective operation of the exhaust-gas purification component 2 is possible.