DE102013215594A1 - Exhaust system for an internal combustion engine - Google Patents

Abstract

An exhaust system for an internal combustion engine is proposed with at least one exhaust pipe (1) and a pipe (1) arranged connecting piece (3) for Abgasdruckbeaufschlagung a pipe near sensor (6) for the dynamic measurement of the pressure in the pipeline (1). wherein the connecting piece (3) is formed with a device for reducing the application of heat from the exhaust gas to a component coupled to the connecting piece with the sensor (6) to the exhaust gas pressure line.

Description

The present invention relates to an exhaust system for an internal combustion engine with at least one exhaust-carrying pipe and a pipe arranged on the pipe connection for Abgasdruckbeaufschlagung a near-pipeline sensor for the dynamic measurement of the pressure in the pipeline.

Exhaust systems of internal combustion engines may have sensors that serve, for example, the measurement of the exhaust gas composition. Also, a sensor may be provided which serves to measure the pressure upstream of a provided in the exhaust system particulate filter. If the degree of loading of the particulate filter with soot particles becomes too great, a regeneration process is started in dependence on the measured pressure, with which the soot particles are burnt off in a controlled manner in order to reduce the back pressure in the exhaust gas system to a predetermined value.

In this case, to measure the pressure, a pressure measuring sensor arranged at a distance from a pipeline of the exhaust system can be used, which is arranged on the body of a vehicle equipped with the internal combustion engine. For static pressure measurement, the pressure prevailing upstream of the particle filter is transmitted to the pressure measuring sensor via a connecting hose which is fixed to a connecting piece on the pipeline. The connecting hose is elastic and can compensate for the operational length and shape changes of the pipeline.

In this case, a cost-effective component which is uncoupled from the high temperatures of the pipeline can be used as the connecting tube, in that the connecting piece is made of a metallic material and has a large longitudinal extent, so that the heat exerted on the connecting tube, resulting from the pipeline, which is forwarded by heat conduction via the connecting piece to the connecting hose can be reduced due to the cooling of the connecting piece by wind and Wärmestrählung over its length. Therefore, a static pressure measurement can make use of long pressure lines to mitigate the problem of heat input of the elastic connection tube.

Long pressure lines are disadvantageous in dynamic pressure measurements, in which dynamically changing pressures are measured at short time intervals, since run-time errors can arise due to long pressure lines. If a long elastic connecting hose for pressure transfer between the place where the pressure is tapped and the place where the pressure is measured in an exhaust system so a branch of the pipeline and a spaced apart arranged pressure measuring sensor used, the pressure measuring signal by movements of the connecting hose also be falsified.

A dynamic pressure measurement is used, for example, in a system for active noise control, in which the user of a vehicle disturbing noise by the active loading of the vehicle interior with phase-shifted to the disturbing noise sound waves are attenuated, leading to an erasure of the user as disturbing noises should take sound waves taken.

For this purpose, microphones are arranged in the vehicle interior, which serve to detect the noise and the supply of the control electronics with input signals.

Also, in an exhaust system, an actuator for acting on the combustion noise of the internal combustion engine may be provided with antiphase sound waves, which can be used to extinguish or attenuate the noise emission of the internal combustion engine. For this purpose, the sound waves to be damped must be detected metrologically and fed to a control loop. For this purpose, the highly dynamic control loop must be supplied with pressure input signals in order to provide phase-shifted sound waves via the actuator can. A long pressure measuring line is for this purpose unsuitable, since conditional propagation delays would adversely affect the reaction rate of the control loop.

If dynamic pressure measuring operations of the pressure prevailing in an exhaust system are to be carried out, then a corresponding pressure measuring sensor must be applied near the pipeline of the exhaust system to avoid the signal distortions described above while largely avoiding connection of the sensor to the vehicle.

The pressure measuring sensor can be attached for this purpose, for example, to a muffler or actuator of the exhaust system or an existing actuator on the exhaust system. Since the exhaust system undergoes temperature changes due to changes in length, the pressure line must be formed by the pipe to the pressure measuring sensor elastic.

The small, available in the underbody of a vehicle space for the integration of the exhaust system with a arranged for dynamic pressure measurement Pressure measuring leads to the fact that a metallic connecting piece for receiving an elastic pressure line can be formed only very short, so that it can dissipate little heat between its branch on the pipe and the location of the connection of the elastic pressure line to the connection piece.

As a result, the thermal load of the elastic pressure line at the location of their connection to the connecting piece is very high and especially in high temperature travel, so for example driving the vehicle with high engine load, quickly exceeds the specification-related allowable limits for an elastic pressure line, which is for example a silicone Elastomer hose can act.

Based on DE 198 54 095 A1 An exhaust system with an exhaust pipe for guiding the exhaust gas to a catalyst has become known, which quickly reaches its light-off temperature, since an air gap insulation of the exhaust pipe ensures that the exhaust gas emits little heat to the environment on its way to the catalyst.

Based on DE 10 2011 086 798 A1 a metering module with air gap insulation has become known, which is provided for introducing a reducing agent into the exhaust gas tract of an internal combustion engine and the air gap insulation is used for cooling the metering module by convection.

With reference to the applicant EP 2 607 640 A1 an actuator arrangement for an active exhaust system has become known, which in 7 a arranged around a sensor cooling channel for cooling the sensor shows.

Proceeding from this, the present invention is based on the object to provide an exhaust system for an internal combustion engine, which allows a dynamic measurement of the pressure prevailing in the exhaust system.

To solve this problem, the invention has the features specified in claim 1. Advantageous embodiments thereof are described in the further claims.

The invention provides an exhaust system for an internal combustion engine with at least one exhaust pipe leading and arranged on the pipe connection piece for Abgasdruckbeaufschlagung a close-coupled sensor for dynamic measurement of the pressure in the pipeline, wherein the connecting piece with a device for reducing the admission of the connecting piece with the component coupled to the sensor for the exhaust gas pressure line is formed with heat from the exhaust gas.

In other words, the invention provides an exhaust system with an at least single-flow pipe whose cross-section can be arbitrarily formed and a connection piece arranged on the pipe whose cross-section can likewise be of any desired configuration and via which the exhaust gas pressure prevailing in the exhaust system moves in the direction of the pipe arranged pressure measuring sensor can propagate to allow a dynamic measurement of prevailing in the pipeline exhaust pressure.

The connecting piece can be connected to the pressure measuring sensor via a component in the form of an elastic connecting hose, which is connected to the connecting piece and directly or with the interposition of a further fluid line to the pressure measuring sensor. By means provided on the connection piece for reducing the admission of the component with heat from the exhaust gas, the connection piece itself is cooled, not the sensor, as is the case with the document described above, thereby achieving that of the exemplary elastic connection hose is not burdened with a temperature profile exceeding its specification at the place of its attachment to the connecting piece.

It is provided according to a development of the invention that the device has a first, extending away from the pipe connecting piece section and a second, extending in the direction of the pipe towards the connecting piece section. Thus, a configuration is provided in which the connecting piece has two sections, of which the first section runs away from the pipeline from the branch of the connecting piece on the pipeline and the second section extends again in the direction of the pipeline.

Such a configuration allows the formation of a connecting piece corresponding to an elongate connecting piece with regard to the longitudinal extent, but without requiring the space required for receiving an elongate connecting piece.

It is provided according to a development of the invention that the second section has a smaller longitudinal extent than the first section, so the second section does not run back to the pipe back. A thus formed connection piece allows the dissipation of heat along the course of the connecting piece and thus provides in the region of the second portion of the connecting piece a place for the attachment of an elastic connecting hose, which experiences at this point a heat load, the largely corresponds to the heat load at the end of a known elongated connection piece, but without requiring its space requirement.

The second section has a larger transverse extent than the first connection piece section and is arranged coaxially or at an angle to the first connection piece section and an air gap is formed between the connection piece sections. The air gap ensures that thermal insulation takes place between the two connection piece sections and thus the larger outer dimensions of the second connection piece section surrounding the first connection piece section at least along a partial longitudinal extension of the first end connection section has a significantly lower temperature level than the first connection piece section. The second portion may coaxially surround the first portion or may have an angle relative to the first spud portion, that is, for example, form a flared spigot that surrounds the first spud portion.

If the elastic connection hose is attached to the second connection piece section, then it is exposed to a significantly lower temperature load than would be the case if it were fixed at the end of the first connection connection section. In the air gap between the two connecting piece sections, moreover, during the drive of the vehicle with the exhaust system according to the invention, the heat dissipation in the area of the air gap encouraging turbulence and thus active cooling of the second connecting piece section through the air gap space occurs.

The transition region between the two connecting-pipe sections can be annular in a plan view, so that the first connecting-pipe section merges radially inward into the transitional region and the transitional region merges radially outward into the second connecting-pipe section.

According to a development of the invention, the second connecting-piece section is formed on the outer circumference for receiving the already mentioned elastic connecting element in the form of, for example, an elastic connecting hose, which connects the sensor to the second connecting-piece section in a pressure-tight manner. For this purpose, the second connection piece section may have at least one radial extension over which the elastic connection hose is pushed and there undergoes a radial widening and thus the pressure-tight connection between the connection hose and the connection piece can be realized without further fastening means.

The first and / or second connecting piece section is preferably formed from a metallic material, for example the material from which the pipeline of the exhaust system is formed, so that the second connecting piece section experiences a corresponding cooling via the turbulences in the air gap arising during the travel of the vehicle.

In addition to the already described possibility of air-gap insulation and the correspondingly formed connecting piece sections, it is also provided according to a development of the invention that the device has a lamella tube, which is arranged in the region between a branch of the pipe and the pressure measuring sensor. The lamellar tube has a large surface area on its outer circumference, so that a location of the attachment of the sensor directly to the lamellar tube or of an elastic connecting tube, which is connected to the sensor and provided at the lamellar tube, has a significantly lower temperature level as the branch itself and thus in the case of a direct arrangement of the sensor on the fin tube of the sensor input and in the case of an arrangement of a connecting tube on the fin tube of the connecting tube undergoes a significantly reduced heat load.

Quite generally, it is provided according to the invention that the connecting piece and / or an attachment point formed on the lamellae pipe for the elastic connecting hose has a closed profile and in particular is circular.

According to a development of the invention, it is also provided that the connection piece is arranged on the pipe so that condensate flows from the connection piece into the pipe. Such a configuration has the advantage that condensate present in the exhaust system, which enters the connection piece, flows back into the pipe and at low temperatures does not lead to the formation of ice in the connection piece and / or the laminated pipe and / or plugging the connection piece the connection hose and / or the Druckmesssensoreingang can come.

Also, according to a development of the invention, the connecting piece can be beveled in the region of the end portion of the second connecting piece section, wherein the beveled end portion has a shorter region in the longitudinal direction of a provided with the exhaust system Vehicle has forward lying and thus it comes to the driving of the vehicle to intense air turbulence in the region of the air gap between the two connecting piece sections, whereby the cooling of the second connection piece section is further improved.

The invention will be explained in more detail below with reference to the drawing. This shows in:

1 a schematic representation of a known piping close arrangement of a pressure measuring sensor;

2 a schematic representation similar 1 but showing an embodiment of the invention;

3 a representation similar 2 showing the spigot with the connecting hose disconnected therefrom;

4 a representation similar 3 showing a second embodiment of the invention;

5 a schematic representation of a third embodiment of the invention; and

6 a representation similar 5 showing a fourth embodiment.

1 The drawing shows a schematic representation of a known exhaust system with piping near arrangement of a pressure measuring sensor for the dynamic measurement of the pressure prevailing in the pipeline.

On a pipeline 1 , in which the exhaust gas flows in the arrow direction, is a muffler or actuator 2 arranged, which serves to reduce the noise emission of an internal combustion engine, not shown. The silencer or actuator 2 has a housing which can be used for the arrangement of the pressure measuring sensor described below. Also, the exhaust system may include the actuator already mentioned above, which is used for damping the noise emissions of the internal combustion engine and also has a housing on which the pressure measuring sensor can be set.

At the pipeline 1 is a connecting piece 3 provided, on which an elastic connecting hose 4 is arranged and can be fixed there via a fastener, such as a spring ring or a hose clamp. At the other end of the connection hose 4 is again a fastener 5 provided, which the connection hose 5 at an input of a pressure measuring sensor 6 pressure tight.

The pressure measuring sensor 6 Can via a holding member 7 on the housing of the muffler or actuator 2 be set releasably. In this way, a piping near arrangement of the pressure measuring sensor 6 be realized, but with significant disadvantages, which lead to such a known arrangement is not suitable for use.

At the piping near location of the connection of the connecting hose 4 on the connecting piece 3 can be measured in the known arrangement, a temperature T1, which reaches values of up to 320 ° C in real operation of the internal combustion engine. Such temperature values are far beyond the specification range of connection hoses in the form of silicone elastomer hoses, which are usefully used for mass production, and which are usually released for upper temperature ranges of 200 ° C.

At the other end of the connection piece 3 Temperatures T2 of about 180 ° C, the coverage area between the location where the temperature T1 is measured and the location at which the temperature T2 is measured, for safe and pressure-tight connection of the connecting tube 4 on the connecting piece 4 needed, so can not be shortened.

2 The drawing shows an embodiment of an exhaust system according to the invention. At the pipeline 1 is a silencer or actuator 2 arranged, from which a connecting piece 3 branches off, on which a connecting hose 4 is arranged, the connecting piece 3 pressure-tight with an input of a pressure measuring sensor 6 connects, via a holding component 7 on the silencer or actuator 2 is fixed.

For further explanation of this embodiment is on 3 referred to the drawing. This shows the connection piece 3 with a first connection piece section 8th and a second connection piece section 9 , The first connection piece section 8th extends largely vertically from the pipeline 1 in the upward direction to the pressure measuring sensor 6 and has a transition region at the upper end region 10 on the first spigot section 8th with the second connection piece section 9 combines.

The second connection piece section 9 runs from the transition area 10 towards the pipeline 1 but has a shorter longitudinal extent than the first connection piece section 8th and larger outer dimensions than the first spud section 8th , In the illustrated embodiment, both are spigot sections 8th . 9 circular tube-shaped, the second Connector fitting section 9 thus has a larger outer diameter than the first connection piece section 8th ,

In this way, radially outward of the first port section 8th and radially within the second port portion 9 an air gap space 11 formed, the thermal insulation of the second connection piece section 9 serves, in which the in 3 drawn off drawing shown connection hose 4 can be attached.

Temperature measurements with otherwise unchanged temperature measurement conditions with continuous engine full load have shown that now the contact area between the connection piece 3 and the connection hose 4 , where the highest temperatures prevail, the transition area 10 between the two spigot sections 8th . 9 is and there maximum temperatures of 160 ° C exist. These temperatures can be covered with a cost-effective silicone elastomer hose.

4 The drawing shows a schematic representation of a second embodiment of the invention, which differs from the in 2 and 3 illustrated embodiment characterized in that the pipe near the end portion 12 is formed bevelled. This configuration results in that during a driving movement of the vehicle equipped with the exhaust system according to the invention, not shown in detail, the opposite to the arrow in the pipeline 1 shown direction of the exhaust gas flow, strong turbulence in the region of the air gap space 11 occur that further reduce the measured temperature T2. In this way, the use of connecting hoses can be achieved from even more cost-effective materials.

5 The drawing shows a further embodiment of an exhaust system according to the present invention. On a short in this embodiment, connecting piece 3 closes a lamellae 13 at, on whose, the connecting piece 3 opposite end portion 14 , the connection hose 4 can be determined, which is the pipeline 1 pressure-tight with the pressure measuring sensor not shown here 6 combines.

The lamellae pipe 13 can be arranged on the underbody of the vehicle not shown in such a way that it is cooled during a driving movement of the vehicle by the prevailing in the region of the subsoil airflow.

Finally shows 6 the drawing shows a further embodiment, different from the in 5 the drawing illustrated embodiment differs in that the pressure measuring sensor 6 without interposition of a connecting hose directly on the end section 14 of the finned tube 13 can be determined.

The invention provides the possibility of integration of a pressure measuring sensor close to the pipeline to the exhaust system for an internal combustion engine of a vehicle, without requiring a large amount of space. The design of the exhaust system so that the required connection for the pressure measuring sensor connection piece is cooled, it is achieved that a pressure-tight connection between the pipe and the pressure measuring sensor provided elastic connecting hose can be carried out inexpensively, without high temperature stable and expensive for mass production special materials to dodge.

The formation of the connecting piece with two connecting piece sections provides for a connecting piece with a large length, but without requiring the space required for the integration of a known connection piece with a long length. Due to the design of the exhaust system with a lamellar pipe in the region between the connecting piece and the pressure measuring sensor, the heat application of a connecting hose arranged between the pressure measuring sensor and the lamellar pipe can be further reduced. In addition, the heat load of the pressure measuring sensor can be reduced via the lamellae.

With regard to features of the invention which are not explained in greater detail above, reference is expressly made to the claims and the drawings, moreover.

LIST OF REFERENCE NUMBERS

1

pipeline

2

Silencer, actuator

3

spigot

4

connecting hose

5

fastener

6

Pressure measuring sensor

7

holding member

8th

first connecting piece section

9

second connection piece section

10

Transition area

11

Air gap

12

end

13

finned

14

end

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19854095 A1 [0013]
• DE 102011086798 A1 [0014]
• EP 2607640 A1 [0015]

Claims (12)

Exhaust system for an internal combustion engine with at least one exhaust-carrying pipeline ( 1 ) and one on the pipeline ( 1 ) arranged connecting piece ( 3 ) for Abgasdruckbeaufschlagung a pipe near sensor ( 6 ) for the dynamic measurement of the pressure in the pipeline ( 1 ), characterized in that the connecting piece ( 3 ) with a device for reducing the admission of a connecting piece with the sensor ( 6 ) to the exhaust pressure line coupled component is formed with heat from the exhaust gas. Exhaust system according to claim 1, characterized in that the device has a first ( 8th ), away from the pipeline ( 1 ) extending spigot portion and a second ( 9 ), in the direction of the pipeline ( 1 ) has extending connecting piece section. Exhaust system according to claim 2, characterized in that the second connecting piece section ( 9 ) has a smaller longitudinal extent than the first connection piece section (FIG. 8th ) having. Exhaust system according to claim 2 or 3, characterized in that the second connecting piece section ( 9 ) has a larger transverse extent than the first connecting piece section ( 8th ) and coaxial or at an angle to the first connection piece section ( 8th ) and between the connecting piece sections ( 8th . 9 ) an air gap space ( 11 ) is trained. Exhaust system according to one of claims 2 to 4, characterized in that in the transition region ( 10 ) between the two connecting piece sections ( 8th . 9 ) A connecting portion is arranged, which is annular in a plan view. Exhaust system according to one of claims 2 to 5, characterized in that the second connecting piece section ( 9 ) on the outer circumference for receiving an elastic connecting element ( 4 ) is formed, which the sensor ( 6 ) with the second connection piece section ( 9 ) connects pressure-tight. Exhaust system according to one of claims 2 to 6, characterized in that the first ( 8th ) and / or second ( 9 ) Connecting piece section are formed of a metallic material. Exhaust system according to one of the preceding claims, characterized in that the device is a lamellae ( 13 ) having. Exhaust system according to claim 8, characterized in that the lamellae ( 13 ) the pipeline ( 1 ) with the sensor ( 6 ) connects pressure-tight. Exhaust system according to one of the preceding claims, characterized in that the connecting piece ( 3 ) has a closed profile in cross-section and in particular is annular. Exhaust system according to one of the preceding claims, characterized in that the connecting piece ( 3 ) on the pipeline ( 1 ) is arranged so that condensate from the connecting piece ( 3 ) into the pipeline ( 1 ) drains off. Exhaust system according to one of the preceding claims, characterized in that the connecting piece ( 3 ) a bevelled end portion ( 12 ), the shorter region of which lies in the front in the longitudinal direction of a vehicle provided with the exhaust system.

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