EXHAUST-GAS SYSTEM

Abstract

An exhaust-gas system for guiding and aftertreating exhaust gases from an exhaust-gas source, such as an internal combustion engine, with a flow section through which the exhaust gas may flow, with at least one component which is provided for the exhaust-gas aftertreatment, is arranged in the flow section and through which the exhaust gas may flow, and with an actuator for influencing the exhaust-gas flow in the flow section. The actuator is in fluid communication with the gas volume in the flow section, as a result of which the flow direction of the exhaust gas which flows through the flow section is influenced.

Claims

1. An exhaust-gas system for guiding and aftertreating exhaust gases from an exhaust-gas source, such as an internal combustion engine, comprising: a flow section through which exhaust gas may flow; at least one component which is provided for the exhaust-gas aftertreatment, the at least one component arranged in the flow section and through which the exhaust gas may flow; and at least one actuator for influencing the exhaust-gas flow in the flow section; wherein the actuator is in fluid communication with the gas volume in the flow section, as a result of which the flow direction of the exhaust gas which may flow through the flow section is influenced.

2. The exhaust-gas system of claim 1, the at least one component further comprising at least one of a heating device, a catalytic converter, or an evaporation device.

3. The exhaust-gas system of claim 1, the at least one actuator further comprising a pump.

4. The exhaust-gas system of claim 3, the exhaust-gas system further comprising: a bypass which leads from a point downstream of the at least one component to a point upstream of the at least one component; wherein the exhaust gas located in the flow section is at least partially conveyed along the bypass by the at least one actuator.

5. The exhaust-gas system of claim 4, wherein the bypass is closed or is opened up by at least one flap.

6. The exhaust-gas system of claim 1, wherein the at least one actuator arranged at the flow section.

7. The exhaust-gas system of claim 6, the at least one actuator further comprising a first actuator and a second actuator, wherein the first actuator is arranged downstream of the at least one component and the second actuator is provided upstream of the at least one component.

8. The exhaust-gas system of claim 7, wherein the first actuator and the second actuator generate a pulsation of the gas volume located in the flow section, the pulsation of the gas volume enabling the flow direction of the gas volume to be reversed.

9. The exhaust-gas system of claim 6, the at least one actuator further comprising an expandable or compressible actuator volume, wherein a portion of the gas in the flow section is sucked into the actuator volume by expansion of the actuator volume and, when the actuator volume is compressed, the gas in the actuator volume is pressed into the flow section.

10. The exhaust-gas system of claim 9, wherein the at least one actuator is arranged upstream of the at least one component which is provided for the exhaust-gas aftertreatment.

11. The exhaust-gas system of claim 1, further comprising at least one closing device is provided in the flow section, wherein the flow section is opened or closed by the at least one closing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the following, the invention is explained in detail using exemplary embodiments with reference to the drawings. In the drawings:

[0032] FIGS. 1 to 4 each show a sectional view through a flow section with two catalytic converters arranged therein and a heating element arranged between the catalytic converters, the exemplary embodiments of the Figures differing in each case by the type and arrangement of the actuators via which the gas movement in the flow section is influenced.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0034] FIG. 1 shows a sectional view through a flow section 1 through which an exhaust gas from an exhaust-gas source may flow along the direction 2. After flowing through the flow section 1, the exhaust gas flows out of the flow section 1 along the direction 3.

[0035] Two catalytic converters 4 and a heating device 5, through which the flow may pass successively, are arranged within the flow section 1.

[0036] This design is identical in FIGS. 2 to 4 below, and therefore it is not described further in the Figures and the same reference signs are also used for identical parts.

[0037] Two actuators 6 are arranged on the housing forming the flow section 1. The actuators 6 serve to influence the exhaust-gas flow in the interior of the flow section 1.

[0038] In the example of FIG. 1, the actuators 6 are identical, but oriented in opposite directions to one another. One of the actuators 6 is arranged downstream of the catalytic converters 4, the other actuator 6 is arranged upstream of the catalytic converters 4.

[0039] The actuators 6 in the exemplary embodiment of FIG. 1 generate a pulsation of the gas located in the flow section 1, for example by pressure waves. The actuators 6, which are oriented in an opposed manner to one another, may for this purpose, for example, introduce phase-shifted pressure waves into the flow section 1 in order to generate a movement of the exhaust gas counter to the actual flow direction.

[0040] FIG. 2 shows an actuator 7 which is formed by a pump. The actuator 7 transports exhaust gases via a bypass 8, which branches off downstream of the catalytic converters 4 from the flow section 1 and opens upstream of the catalytic converters 4 into the flow section 1. By adding the exhaust gas again upstream of the catalytic converters 4 and the heating device 5, the exhaust gas may flow through them again and thus, on the one hand, is heated up further and, on the other hand, the pollutants contained in the exhaust gas are further converted, if a complete conversion has not yet been achieved during the first pass through.

[0041] Closure elements, for example in the form of rotatably mounted flaps, are also provided in the flow section 1 upstream and downstream of the bypass 8 in the flow direction. By closing the flow section 1 using the two closure elements, the gas volume located in the cavity formed between the closure elements is conveyed in a circuit through the catalytic converters 4 and the heating element 5 by the actuator 7, which is formed for example by a pump. The gas volume is pumped here into the bypass 8 in each case downstream of the last catalytic converter 4 in the flow direction and pumped back into the main flow section upstream of the first catalytic converter 4 in the flow direction.

[0042] By circulating the gas volume, the temperature at the catalytic converters 4 is kept high for longer. This is advantageous, for example, when the internal combustion engine is not running, since the absence of new exhaust gas flowing in would otherwise result in a significant reduction in the temperature at the catalytic converters 4. With active use of the heating element 5, the cooling of the catalytic converters is accordingly delayed even further.

[0043] FIG. 3 and FIG. 4 show an actuator 9 at the flow section in two different operating states. The actuator 9 is formed by a compressible volume which is compressed in a similar way to a bellows. In FIG. 3, the actuator 9 is shown in the compressed state, while the actuator 9 in FIG. 4 is shown non-compressed in the initial state.

[0044] The compression and the subsequent expansion work in a similar way to a bellows. In this way, some of the exhaust gas in the flow section 1 is sucked up and expelled again. A pulsation of the exhaust gas is thereby generated within the flow section 1, as a result of which the exhaust gas is at least partially guided past the catalytic converters 4 and the heating device 5 several times.

[0045] FIGS. 3 and 4 each also show the flap 10, which is rotatably mounted in the flow section 1, at the end of the flow section 1. The cross section of the flow section 1 is closed or opened up by the flap 10. As a result, the gas volume within the flow section 1 is limited. The outflow from the flow section 1 is also at least temporarily interrupted, which is why it is easier to generate a reverse movement of the exhaust gas.

[0046] The exemplary embodiments of FIGS. 1 to 4 are not of a restrictive nature and serve to illustrate the concept of the invention.

[0047] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.