GB2535001A - Exhaust pipe element for an exhaust system of a vehicle, in particular a motor vehicle - Google Patents

Abstract

An exhaust pipe element 16 has at least one exhaust conduit 18 through which exhaust gas of a combustion engine can flow. The exhaust conduit 18 has at least one diversion zone (A, Fig 2f) in which the exhaust gas flowing through the diversion zone (A, Fig. 2f) is diverted at least 70 degrees. The exhaust pipe element 16 is, at least in the diversion zone (A, Fig. 2f), formed by means of hydroforming. The diversion zone (A, Fig 2f) may have a first portion where the conduit 18 widens conically, a second portion where the conduit tapers conically, and a third portion (S, Fig. 2f) in the form of a straight circular cylinder. The cross section of the third portion (S, Fig. 2f) may be smaller than the first or second portions. The exhaust pipe element 16 may be made from aluminized stainless steel. An exhaust system 12 for a vehicle, containing an exhaust pipe element 16 is also claimed.

Description

Exhaust Pipe Element for an Exhaust System of a Vehicle, in particular a Motor Vehicle The invention relates to an exhaust pipe element for an exhaust system of a vehicle, in particular a motor vehicle.

US 2011/0037258 Al shows a conduit coupling including first and second conduits, and annular adapter and a clamp. The first conduit has an angular flange on an outer surface adjacent to a first end. The adapter is coupled to the outer surface of the first conduit and has an annular first engagement surface positioned adjacent to the flange and an annular second engagement surface that is spherical and convex. The second conduit has a flared end with an inner surface and an outer surface. The inner surface includes an adapter engagement surface that is spherical and concave and engagable with the second engagement surface. The outer surface includes a clamp engagement surface and the clamp includes a flared end engagement surface that is engagable with the clamp engagement surface. The clamp is configured to urge the flared end, adapter and annular flange together.

It is an object of the present invention to provide an exhaust pipe element by means of which exhaust gas of a combustion engine can be guided particularly advantageously, wherein the exhaust pipe element can be manufactured in a cost-effective way.

This object is solved by an exhaust pipe element having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are indicated in the other patent claims.

The exhaust pipe element according to the present invention has at least one exhaust conduit through which exhaust gas of a combustion engine can flow. For example, the combustion engine is configured as an internal combustion engine. The combustion engine can be part of a vehicle, in particular a motor vehicle, which can be driven by the combustion engine. For example, the exhaust pipe element is used to guide the exhaust gas away from the combustion engine.

The exhaust conduit has at least one diversion zone in which the exhaust pipe element is formed in such a way that the exhaust gas flowing through the diversion zone is diverted at least 70°degrees, in particular at least 90°de grees. For example, the exhaust gas flowing through the exhaust pipe element enters the diversion zone in a first direction of flow. Moreover, for example, the exhaust gas flowing through the exhaust pipe element exits the diversion zone in a second direction of flow. Since, by means of the diversion zone, the exhaust gas flowing through the diversion zone is diverted, the second direction of flow extends angularly to the first directional off-flow, wherein the first direction of flow and the second direction of flow confine an angle of at least 70 degrees, in particular of at least 90 degrees.

In order to guide the exhaust gas particularly advantageously and manufacture the exhaust pipe element in a particularly cost-effective way, the exhaust pipe element is, at least in the diversion zone, formed by means of hydroforming. Thus, the exhaust pipe element according the present invention can be configured as an optimized and hydroformed low profile exhaust elbow addressing elevated back pressure which, for example, can be measured in conventional exhaust systems. Since the exhaust pipe element is formed in such a way that the exhaust gas is diverted at least 70 degrees, in particular 90 degrees, interference or clash of the exhaust pipe element with surrounding components of the vehicle can be avoided. The optimized exhaust pipe element according to the present invention also simplifies manufacture of the part from a cut and welded part to a hydroformed part without any welds. This eliminates the small amount of resistance to flow created by hard mitered corners and weld pools. The simplified manufacturability also addresses reliability issues with failed welds seen on conventional solutions. Lastly, the hydroformed exhaust pipe element eliminates gas leakage of exhaust systems, in particular under cabs or sleepers of vehicles, in particular commercial vehicles.

By using hydroforming to form the exhaust pipe elements the hydroformed exhaust pipe element eliminates three processes used to manufacture conventional exhaust pipe elements: cutting, welding and bending. Thereby, costs of the exhaust pipe element can be kept particularly low and an improved reliability can be realized. Moreover, by using hydroforming and optimized geometry improving flow of compressible gas such as exhaust gas can be realized thereby reducing backpressure on the engine which improves fuel efficiency of the vehicle. Moreover, the hydroformed exhaust pipe element is also more attractive in comparison with conventional exhaust pipe elements thereby appealing better to a person.

Preferably, the exhaust pipe element is made of aluminized steel, in particular aluminized stainless steel such as aluminized 409 stainless steel which reduces corrosion of the part thereby improving long term life and appearance of the part, even under elevated temperature and flow seen within the exhaust system.

Further advantages, features, and details of the invention derive from the following description of preferred embodiments as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respectively indicated combination but also in other combination or taken alone without leaving the scope of the invention.

The drawings show in: Fig. 1 a schematic perspective view of an exhaust system for a motor vehicle, the exhaust system comprising at least one exhaust pipe element being formed by means of hydroforming; Fig. 2a a schematic perspective view of a first embodiment of the exhaust pipe element; Fig. 2b a schematic front view of the exhaust pipe element according to the first embodiment; Fig. 2c a schematic back view of the exhaust pipe element according to the first embodiment; Fig. 2d a schematic bottom view of the exhaust pipe element according to the first embodiment; Fig. 2e a schematic top view of the exhaust pipe element according to the first embodiment; Fig. 2f a schematic side view of the exhaust pipe element according to the first embodiment; Fig. 3a a schematic side view of a prior art solution of the exhaust pipe element; Fig. 3b a schematic top view of the exhaust pipe element according to the prior art solution; Fig. 4a a schematic side view of a second embodiment of the exhaust pipe element; Fig. 4b a schematic top view of the exhaust pipe element according to the second embodiment, Fig. 5a a schematic side view of a third embodiment of the exhaust pipe element; and Fig. 5b a schematic top view of the exhaust pipe element according to the third embodiment; In the figures the same elements or elements having the same functions are indicated by the same reference signs.

Fig. 1 shows an exhaust system 10 for a vehicle, in particular a motor vehicle. The motor vehicle comprises a combustion engine which is configured as an internal combustion engine. For example, the internal combustion engine is configured as a reciprocating piston engine by means of which the vehicle can be driven. Preferably, the vehicle is configured as a commercial vehicle such as a truck or tractor. During fired operation of the combustion engine said combustion engine provides exhaust gas, wherein the exhaust system 10 is used to guide the exhaust gas away from the combustion engine. Thus, the exhaust gas provided by the combustion engine can flow through the exhaust system 10. The exhaust system 10 comprises an exhaust gas aftertreatment device 12 through which the exhaust gas can flow, wherein the exhaust gas aftertreatment device 12 is configured as an exhaust gas aftertreatment box. For example, the exhaust gas aftertreatment device 12 comprises at least one catalytic converter and/or at least one particle filter so that the exhaust gas can be aftertreated by means of the exhaust gas aftertreatment device 12.

Moreover, the exhaust system 10 comprises a plurality of exhaust pipe elements 14 and 16 which are fluidically connected to the exhaust gas aftertreatment device 12 so that the exhaust gas flowing through the exhaust gas aftertreatment device 12 can flow out of the exhaust gas aftertreatment device 12 and into the exhaust pipe elements 14 and 16, wherein the exhaust gas can flow through the exhaust pipe elements 14 and 16. As can be seen from Fig. 1, the exhaust pipe element 14 is fluidically connected to the exhaust gas aftertreatment device 12 by the exhaust pipe element 16, wherein Figs. 2a-f show a first embodiment of said exhaust pipe element 16. As will be described in the following, the exhaust pipe element 16 is configured as an optimized and hydroformed low profile exhaust elbow by means of which the exhaust gas can be guided in a particularly advantageous way, wherein said low profile exhaust elbow can be manufactured in a particularly cost-effective way.

As can be seen from Figs. 2a-f, the exhaust pipe element 16 comprises at least one exhaust conduit 18 through which the exhaust gas can flow. In Fig. 2f, a path of flow and, thus, a direction of flow of the exhaust gas flowing through the exhaust pipe element 16 is illustrated by a dashed line 20. The exhaust pipe element 16 is made of a metallic material such as steel. Preferably, the exhaust pipe element 16 is made of an aluminized stainless steel.

As can be seen from Fig. 2f the exhaust conduit 18 and, thus, the exhaust pipe element 16 have at least one diversion zone A in which the exhaust pipe element 16 and, thus, the exhaust conduit 18 are formed in such a way that the exhaust gas flowing through the diversion zone A is diverted at least 70 degrees. In the embodiments shown in the figures, the exhaust pipe element 16 is, at least in the diversion zone A, formed in such a way that the exhaust gas flowing through the diversion zone A and, thus, the exhaust pipe element 16 is diverted at least 90 degrees.

In order to guide the exhaust gas in a particularly advantageous way and manufacture the exhaust pipe element 16 in a particularly cost-effective way, the exhaust pipe element 16 is formed by means of hydroforming. The exhaust pipe element 16 is formed by means of hydroforming in the diversion zone A as well as in a straight pipe zone S and in a third zone Z, wherein the diversion zone A is arranged between the straight pipe zone S and the third zone Z with respect to the path of flow of the exhaust gas flowing through the exhaust pipe element 16. This means the straight pipe zone S is fluidically connected with the third zone Z by the diversion zone A. Moreover, in Fig. 2f, points 1, 2, 3, 4 and 5 are shown, wherein said points 1, 2, 3, 4 and 5 are points or parts of the path of flow illustrated by the dashed line 20.

As can be seen from Figs. 1 to 2f, the exhaust pipe element 16 is a packaging optimized elbow for low resistance flow of a compressible fluid such as the exhaust gas. For example, said elbow is a 4" or 5" diameter aluminized 409 stainless steel tube, hydroformed into a one-piece low profile elbow for the purpose of routing high temperature and high flow rate exhaust into, or out of, an after treatment system of a vehicle such as a commercial vehicle where allowable space for the exhaust pipe is restricted due to manufacturing constraints, nearby components or thermal restrictions. In said elbow, the distance from point 1 to point 2 is minimized while the width of the elbow is increased. For example, respective end connections of the elbow are interchangeable and can include Detroit spherical marmon/straight tube ends such as disclosed in US 8328243, Cummins spherical marmon/straight tube ends, conical marmon/straight tube ends or two straight tube ends. The diversion zone A forms a bend by means of which the exhaust gas is diverted.

The elbow reduces exhaust gas flow restriction/pressure loss through the bend (point 2 through point 4) to the outlet (point 4 to point 5) by forming the diversion zone A into a conical expansion (point 2 to point 3)/conical reduction (point 3 to point 4) while increasing the cross sectional area of diversion zone A along the central line to a greater-than straight pipe diameter, while minimizing the distance between point 1 and point 3. For example, the cross sectional area of the exhaust pipe element 16 at a plane cut normal to point 3 along the central line is greater than a cross sectional area of the straight pipe section, point 4 to point 5, wherein said straight pipe section is formed by the straight pipe zone S. Moreover, said central line is illustrated by the dashed line 20. The larger cross sectional area equates to a larger diameter which reduces pressure loss. The geometry has been developed so that gas flow through the bend moves exhaust gas out of the outlet at a similar flow rate as the exhaust gas passes into the inlet. The elbow material was selected to increase the life of the part and aid in corrosion resistance as the elbow is exposed to internal and external corrosive conditions.

The hydroformed elbow improves current exhaust pipe elements by removing manufacturing processes which results in lower costs to manufacture the elbow, eliminating sharp corners and welds (increased flow/increased corrosion resistance) and having improved appearance.

For example, said inlet comprises a through opening 22 through which exhaust gas can flow so that the exhaust gas can flow into the exhaust conduit 18 via the through opening 22. Moreover, said outlet comprises a through opening 24 through which exhaust gas can flow so that the exhaust gas can flow out of the exhaust pipe element 16 via the through opening 24.

As can be seen from Figs. 2a-f, the diversion zone A is formed in such a way that the diversion zone A comprises a first portion in which the exhaust conduit 18 widens conically. Moreover, the diversion zone A is formed, in particular hydroformed, in such a way that the diversion zone A comprises a second portion adjoining the first portion, the exhaust conduit 18 tapering conically in the second portion. With respect to the direction of flow of the exhaust gas the first portion is arranged upstream of the second portion. Moreover, the straight pipe portion S adjoins the second portion so that the straight pipe portion S is arranged downstream of the second portion with respect to the direction of flow of the exhaust gas, wherein, in the straight pipe zone S, the exhaust conduit 18 has the form of a straight circular cylinder. Moreover, for example, the exhaust pipe element 16 has a fourth portion 26 which is arranged upstream of the diversion zone A. For example, in the fourth portion 26 the exhaust conduit 18, in particular its cross section, tapers conically towards the diversion zone A. Figs. 3a and 3b show a prior art solution of the exhaust pipe element 16, wherein Figs. 4a and 4b show a second embodiment. Moreover, Figs. 5a and 5b show a third embodiment of the exhaust pipe element 16.

List of reference signs exhaust system 12 exhaust gas aftertreatment device 14 exhaust pipe element 16 exhaust pipe element 18 exhaust conduit dashed line 22 through opening 24 through opening 26 fourth portion A diversion zone S straight pipe zone Z third zone 1 point 2 point 3 point 4 point point

Claims (7)

1. Patent Claims 1. An exhaust pipe element (16) having at least one exhaust conduit (18) through which exhaust gas of a combustion engine can flow, the exhaust conduit (18) having at least one diversion zone (A) in which the exhaust pipe element (16) is formed in such a way that the exhaust gas flowing through the diversion zone (A) is diverted at least 70 degrees, wherein the exhaust pipe element (16) is, at least in the diversion zone (A), formed by means of hydroforming.
2. 2. The exhaust pipe element (16) according to claim 1, wherein the diversion zone (A) comprises a first portion in which the exhaust conduit (18) widens conically.
3. 3. The exhaust pipe element (16) according to claim 2, wherein the diversion zone (A) comprises a second portion adjoining the first portion, the exhaust conduit (18) tapering conically in the second portion.
4. 4. The exhaust pipe element (16) according to claim 3, wherein the exhaust conduit (18) comprises a third portion (S) adjoining the second portion and the diversion zone (A), the exhaust conduit (18) having the form of a straight circular cylinder in the third portion (S).
5. 5. The exhaust pipe element (16) according to claim 4, wherein the exhaust conduit (18) has a cross section which, in the third portion (S), is smaller than in the first portion and/or second portion.
6. 6. The exhaust pipe element (16) according to any one of the preceding claims, wherein the exhaust pipe element (16) is made of aluminized stainless steel.
7. 7. An exhaust system (12) for a vehicle, the exhaust system (12) comprising at least one exhaust pipe element (16) according to any one of the preceding claims.