LU102337B1

LU102337B1 - Exhaust gas assembly with heatshield

Info

Publication number: LU102337B1
Application number: LU102337A
Authority: LU
Inventors: Axel Fessler; Filip Szybowski
Original assignee: Katcon Global Sa
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-06-22

Abstract

An exhaust treatment assembly comprises a housing and a heat shield assembly being arranged around the housing. The heat shield assembly comprises at least one heat shield opening through which at least one inlet port, which is arranged on and extending outwards from the housing, extends outward of the heat shield assembly. The heat shield opening is dimensioned so that a circumferential gap is formed between the heat shield assembly and the at least one inlet port. According to the present invention the exhaust treatment assembly further comprises a deflector plate, the deflector plate being arranged outside the heat shield assembly near the at least one inlet port. The deflector plate comprises a guide portion and two lateral portions, each one of the guide portion and the lateral portions extending from a first extremity of the deflector plate arranged near the inlet port to a second extremity of the deflector plate. The guide portion is preferably substantially plane and each one of the lateral portions advantageously forms a flange extending from the guide portion in an upwardly, outward direction, so that an angle is formed between the guide portion and a lateral portion, the angle being smaller than 180°, and preferably the angle is comprised between 120° and 60°. Moreover, the guide portion of the deflector plate is configured to collect a liquid leaking near the at least one inlet port.

Description

P-KATCON-012/LU 1 Exhaust gas assembly with heatshield Technical field

[0001] The present invention generally relates to an exhaust gas assembly for a combustion engine and more particularly to an exhaust gas aftertreatment system.

Background of the Invention

[0002] Exhaust lines are used in vehicles for routing exhaust generated by a fuel- burning engine to the atmosphere surrounding the vehicle. It is required to reduce pollutant(s) in the exhaust to an environmentally-acceptable level or form before the exhaust is released to the surrounding atmosphere. Accordingly, there is a requirement to provide an exhaust line for a vehicle with an exhaust gas aftertreatment assembly that operates to reduce pollutant(s) of an exhaust to an environmentally-acceptable form.

[0003] An exhaust treatment assembly typically comprises one or more exhaust gas treatment components such as one or more catalytic converters and/or diesel particulate filters which are arranged within a common housing. Due to the high temperature of the exhaust gases, aftertreatment systems heated up to very high temperatures. As most aftertreatments are located close to the engine (to take benefit of hot gases and facilitate chemical reaction), they are also exposed to flammable liquids (like fuel, motor oil, coolant) which can ignite in contact with high temperature surfaces thereby causing a fire to start. To prevent that, it is important to make sure flammable liquids are not getting in touch with hot surfaces in case of failure. The exhaust treatment assembly therefore usually includes a heat shield assembly with an external encapsulating material arranged around the housing, the space between the housing and the encapsulating material being filled with a mat of thermally insulating material. This heat shield assembly effectively reduces the temperature at the outer surface, thereby preventing liquids to ignite and cause fire.

[0004] However it is not possible to avoid openings in the direct encapsulation of the heat shield assembly. In fact the exhaust treatment assembly comprises one or more mounting brackets which are mounted on the housing of the exhaust gas treatment component and which are used to secure the exhaust treatment assembly to the vehicle structure or the engine. Furthermore, the assembly usually includes

P-KATCON-012/LU 2 one or more inlet ports, which are formed as tap mounted in openings of the housing, each inlet port being configured to accommodate either a sensor device or an urea injection device. Sensor devices are used to monitor the catalytic reaction or the efficiency thereof. Both the mounting brackets and the inlet ports extend outwards from the housing and penetrate the heat shield assembly through openings arranged therein to protrude outside of the assembly.

[0005] In order to allow a proper installation of the encapsulation and due to process tolerances, the heat shield openings are commonly larger than the corresponding cross section of the mounting brackets or the inlet ports, so that a circumferential gap is formed between said heat shield assembly and the mounting bracket and/or inlet port. Due to this gap, the openings let some small surfaces of i the housing exposed to liquid. In most cases, this is not considered as an issue because liquid will not stay in the corresponding area and the risk the liquids to ignite is very low. In other cases however, e.g. if the opening is orientated to the top, liquid can possibly accumulate into this area and this could turn into fire.

[0006] In order to alleviate this risk, manufacturers attempt to review in detail the potential path of the liquid in case of failure and to modify connections accordingly respectively provide additional covers. But these measures remain static tests and could be inefficient in a real-world scenario. Furthermore these measures clearly limit packaging possibilities all the while in modern vehicles it is becoming more and more challenging to find the required mounting space for the aftertreatment components. Object of the invention

[0007] It is therefore an object of the present invention to provide an improved exhaust treatment assembly without the above-described shortcomings. This object is achieved by an exhaust treatment assembly according to claim 1. General Description of the Invention

[0008] In order to achieve the above-mentioned object, the present invention provides an exhaust treatment assembly comprising a housing and a heat shield assembly being arranged around the housing. The heat shield assembly comprises at least one heat shield opening through which at least one inlet port, which is

P-KATCON-012/LU 3 arranged on and extending outwards from the housing, extends outward of the heat shield assembly. The heat shield opening is dimensioned so that a circumferential gap is formed between the heat shield assembly and the at least one inlet port. According to the present invention the exhaust treatment assembly further comprises a deflector plate, the deflector plate being arranged outside the heat shield assembly near the at least one inlet port. The deflector plate comprises a guide portion and two lateral portions, each one of the guide portion and the lateral portions extending from a first extremity of the deflector plate arranged near the inlet port to a second extremity of the deflector plate. The guide portion is preferably substantially plane and each one of the lateral portions advantageously forms a flange extending from the guide portion in an upwardly, outward direction, so that an angle is formed between the guide portion and a lateral portion, the angle being smaller than 180°, and preferably the angle is comprised between 120° and 60°. Moreover, the guide portion of the deflector plate is configured to collect a liquid leaking near the at least one inlet port. In other words, the deflector plate is preferably configured and oriented to form a guide or a groove for liquids (such as but without being limited to oil or fuel) to guide the liquids away from high temperature surfaces towards a safe area where the temperature is cool enough to | prevent any risk of fire.

[0009] The deflector plate according to the present invention is preferably arranged in the vicinity of the inlet port and spans from the inlet port over the circumferential gap to overlap with the outer skin of the heat shield assembly. The deflector plate thus covers the opening of the heat shield assembly in the area where a falling, leaking liquid would accumulate and risk flaming, thus preventing any liquid to come into contact with the hot surfaces of the underlying housing. In other words, any liquid falling from the engine onto the exhaust treatment assembly in the area of the inlet port is received by the defector plate and deflected by the deflector plate towards areas with lower temperatures and thus lower risk of flaming. In this context it will be noted that the exhaust treatment assembly usually has a generally tubular form and that the deflector plate arranged in the vicinity (i.e. near) of an inlet port on the top of the tubular form will deflect the liquid towards the side of the assembly.

[0010] It should be noted that the deflector plate is advantageously positioned above the heat shield opening, and further away from the hot surface of the exhaust

P-KATCON-012/LU 4 treatment assembly than the heat shield assembly. In other words, the deflector plate is preferably arranged outside the heat shield assembly so that a gap is formed between the heat shield assembly and the deflector plate. Advantageously, the gap has a height in the range between 0.5 mm and 10 mm. Therefore, the temperature of the deflector plate is lower than the temperature of the outer surface of the exhaust treatment assembly, so that there is no need to provide any additional insulating means to cover the deflector plate. In other words, the temperature of the bare deflector plate is sufficiently low to prevent any leaking flammable liquid from flaming. It should be noted that the deflector plate may still be coated or covered in order to improve other features thereof and that any covered or coated deflector plates still fall within the scope of the present invention. Coating or covering may include, but without being limited to, coating the deflector plate with a repellant suitable to repel flammable liquids such as fuel, oil or coolant so that any liquid falling on the deflector plate will be quickly evacuated under the joint effect of the geometry of the plate and the repelling effect of the coating.

[0011] The deflector plate thus eliminates the risk of a leaking, flammable liquid penetrating in the insulation material forming the heat shield assembly or under a bracket arranged near the inlet port. The deflector plate therefore address the potential problem of flammable liquid contacting the hot housing surface prior to the impact of the liquid on the housing, thus minimizing the risk of liquid penetrating inside the insulation material forming the heat shield assembly. As a consequence, the deflector plate also reduces the risk of damages to the heat shield assembly and housing of the exhaust treatment assembly and consequent loss of protective function. In other words, the deflector plate prevents damages from happening to the heat shield assembly and housing instead of mitigating their occurrence.

[0012] The deflector plate of the inventive exhaust treatment assembly is particularly well adapted to protect exposed hot surfaces of a catalytic converter or | of an outlet pipe guiding exhaust gases out. However, it is still within the scope of ; the present invention that any exposed hot surface of the exhaust treatment assembly may be protected by the deflector plate. When referring to a catalytic | converter, the term canning could be used instead of housing, as in the present text a canning refers to the housing of a catalytic converter in which active catalysts are enclosed.

P-KATCON-012/LU 5

[0013] In order to facilitate the mounting of the deflector plate and its assembling with the exhaust treatment assembly, the first extremity of the deflector plate is formed to partially encompass the iniet port. By partially but not totally encompassing the inlet port, the deflector plate can be installed by sliding the plate onto the inlet port.

[0014] The deflector plate is preferably mounted on the exhaust treatment assembly near the inlet port so that the deflector plate forms a slope from the inlet port towards the heat shield. This may easily be achieved in embodiments wherein the inlet port extends outward from the housing of the exhaust treatment assembly along a first axis and wherein the deflector plate substantially extends from its first extremity to its second extremity along a second axis: The second axis forms an angle with the first axis. In preferred embodiments, the angle between the first axis and the second axis is comprised between 10° and 170°, preferably 60° and 120°, most preferably between 80° and 100°. The deflector plate will thus present the desired slope, which is favorable for the deflection of liquids toward areas of lower temperature.

[0015] In a preferred embodiment, the deflector plate is made of ferritic steel. The use of ferritic steel minimizes the weight of the deflector plate while retaining a certain stiffness of the construction. It is necessary that the deflector plate present a certain stiffness to avoid the plate from sagging and forming a depression or a recess along the length of the deflector plate, in which liquid may accumulate. However, other materials offering the same advantages regarding the light weight and the stiffness may be used to produce the inventive deflector plate.

[0016] In order to further ensure a light weight combined with a minimal, necessary stiffness of the deflector plate, the thickness of the plate is optimized. Preferably, the deflector plate has a thickness in the range between 0.5 mm and 1.5 x thickness of the bracket. The deflector plate may e.g. have a thickness in the range between

0.5 mm and 10 mm.

[0017] Other dimensions of the deflector plate are also optimized in order to ensure that any liquid collected in and deflected by the plate would be guided toward areas of lower temperature while minimizing the space needed to mount the inventive deflector plate. | |

P-KATCON-012/LU 6

[0018] The deflector plate is preferably made stamping, but any other manufacturing method such as embossing can be used.

[0019] In embodiments, the heat shield assembly may comprise a second heat shield opening through which at least one mounting bracket, which is arranged on and extending outwards from the housing, extends outward of the heat shield assembly, said second heat shield opening being dimensioned so that a circumferential gap is formed between said heat shield assembly and the at least one mounting bracket. Preferably, the mounting bracket is arranged near the inlet port.

[0020] In the present text, the term "mounting bracket" refers to any mounting bracket of the exhaust treatment assembly, and may in particular refer to mounting brackets of the catalytic converter. Due to tolerances of assembly, it is difficult to tightly wrap the heat shield assembly around the bracket, thereby resulting in the second heat shield opening. The deflector plate is advantageously arranged so as to at least partially cover the second heat shield opening near the mounting bracket, thereby preventing flammable liquid from contacting an exposed hot surface in this area and also preventing the flammable liquid from penetrating under the mounting bracket.

[0021] In order to reduce production costs, time needed for assembly and ease the mounting of the deflector plate, the deflector plate may be integrated with the at least one mounting bracket. In other words, the deflector plate and the mounting bracket are attached to each other prior to their attachment to the exhaust treatment assembly. According to this embodiment or to alternative embodiments, the deflector plate may be welded on or brazed to the mounting bracket, preferably the flanges of the deflector plates are welded on or brazed to the mounting bracket. The flanges (or integrated tabs) enable for a direct welding (or brazing) of the deflector plate on the mounting bracket. The direct welding (or brazing) enables a thermal expansion of the deflector plate during operation of the exhaust treatment assembly, minimizing the risk of failure and break (i.e. crack forming) between deflector plate and bracket. It is however noted that other means and methods for attaching the deflector plate to the mounting bracket are not excluded from the scope of the invention, neither are alternative embodiments wherein the deflector plate is directly attached to the heat shield assembly. |

P-KATCON-012/LU 7

[0022] The skilled person will appreciate that the inlet port may be configured to accommodate a sensor device, such as but without being limited to a temperature sensor. Alternatively, the inlet port may be configured to accommodate a urea injection device. The present inventive exhaust treatment assembly may also comprise a plurality of inlet ports configured to accommodate both a plurality of sensor devices and a urea injection device. In such embodiments, the exhaust treatment assembly advantageously comprises as many deflector plates as inlet ports, each deflector plate being arranged in the vicinity of an individual inlet port. In other embodiments, only inlet ports arranged on an upper surface of the exhaust treatment assembly may be provided with a respective deflector plate. Brief Description of the Drawings

[0023] Further details and advantages of the present invention will be apparent from the following detailed description of not limiting embodiments with reference to the attached drawing, wherein: Fig. 1 is a perspective view of an exhaust treatment assembly according to the invention; Fig. 2 is a perspective view from a different angle of the exhaust treatment assembly of Fig. 1; and Fig. 3 is a perspective view of the deflector plate and mounting bracket of the exhaust treatment assembly of Fig.1. Description of Preferred Embodiments

[0024] An exhaust treatment assembly 10 typically comprises one or more exhaust gas treatment components such as one or more catalytic converters and/or diesel particulate filters which are arranged within a common housing 12. A heat shield assembly 14 is arranged around the housing 12 in order to reduce the skin temperature of the exhaust treatment assembly 10. The exhaust treatment assembly 10 usually has a generally tubular form and is provided with end cones 16 having a connection port for connecting the exhaust treatment assembly 10 to exhaust gas pipes.

[0025] While in some configurations, the exhaust treatment assembly 10 and the respective inlet and outlet connection ports with exhaust pipes are arranged in a

P-KATCON-012/LU 8 linear arrangement, the limited mounting space in modern vehicles often requires a more compact configuration with angled inlet and outlet ports. Figs. 1 and 2 show perspective views of such an exhaust treatment assembly 10 in a more compact configuration.

[0026] The heat shield assembly 14 comprises at least two heat shield openings 18 (shown on Fig.1) through which at least one inlet port 20 formed as a protruding tap extending along a first axis A and a bracket assembly, or mounting bracket 22, are arranged on the housing 12 and extend outward of the heat shield assembly 14. In order to allow for a proper installation of the heat shield encapsulation 14 and due to process tolerances, the heat shield openings 18 are larger than the corresponding respective cross section of the inlet port 20 and mounting bracket 22, so that a circumferential gap is formed between the heat shield assembly 14 and the inlet port as well as between the heat shield assembly 14 and the mounting bracket 22. Due to these gaps, the openings 18 let some small surfaces 24 of the housing 12 exposed to liquid.

[0027] The present inventive exhaust treatment assembly 10 will be described. In order to shield the exposed surfaces 22, the exhaust treatment assembly 10 further comprises a deflector plate 28 that is arranged above the heat shield assembly 14 in the vicinity (i.e. near) the inlet port 20 so as to extend from the inlet port along a second axis B.

[0028] The deflector plate is positioned above the heat shield assembly 14 and the exposed surfaces 22. In other words, a gap is provided between the lower surface

28.1 of the deflector plate 28 and both the heat shield assembly 14 and the exposed surfaces 22 of the housing 12. Due to the gap, the upper surface 28.2 of the deflector plate presents a skin temperature lower than the housing 12, so that no additional heat insulation layer is needed to prevent contacting leaking flammable fiuid from flaming. However, a skilled person will appreciate that the plate may be treated in order to improve some properties thereof, and coated or covered deflector plates still fall within the scope of the present invention.

[0029] The deflector plate 28 presents a generally elongate shape in the direction of the second axis B from a first extremity 30.1 to a second extremity 30.2. The first extremity 30.1 may be formed as a half-circle as shown on Fig. 1 to Fig. 3 so as to encompass a half of the inlet port 20. However, alternative embodiments wherein

P-KATCON-012/LU 9 the first extremity 30.1 of the deflector plate 28 presents an alternative shape still formed so as to partially encompass the protruding portion of the inlet port 20 also fall within the scope of the present disclosure. The specific shape of the first extremity 30.1 allows for an easy installation of the deflector plate 28 by sliding the plate toward the inlet port. Due to the specific shape of its first extremity 30.1, the deflector plate 28 glides along and remains in contact with the outer circumference of the inlet port 20.

[0030] The portion of deflector plate 28 extending from the first extremity 30.1 to the second extremity 30.2 forms a guide portion 32. The guide portion 32 presents a slope with respect to the horizontal, which is favorable for the deflection of flammable liquids toward areas of lower temperature. The slope extends from the inlet port 20 in a downward direction toward the heat shield assembly 14. The slope is defined by adjusting an angle a between the first axis A and the second axis B.

[0031] The deflector plate 28 further presents flanges 34, 34’ presenting a length along the axis B and a height extending radially upward from the guide portion. The flanges 34, 34’ advantageously prevent deflected liquid from flowing over the lateral sides of the deflector plate 28. Moreover, the flanges allow for a direct welding of the deflector plate 28 on the mounting bracket 22 arranged near the inlet port 20. The deflector plate 28 is preferably welded on the mounting bracket 22 before assembling the bracket 22 to the exhaust treatment assembly 10 (Fig. 3). The skilled person will appreciate that the deflector plate 28 may also be brazed to the mounting bracket 22, or attached thereto by any suitable fixation method.

[0032] The deflector plate of the inventive exhaust treatment assembly 10 also covers exposed surfaces 24 of the housing 12 near the mounting bracket 22 and prevents liquid from penetrating under the mounting bracket 22 (Fig. 1).

[0033] According to the presently described embodiment, the deflector plate is made of ferritic steel. The use of ferritic steel minimizes the weight of the deflector plate 28 while retaining a certain stiffness of the construction. It is necessary that the deflector plate 28 presents a minimal stiffness to avoid the plate from sagging and forming a depression, or recess, in which flammable liquid may accumulate. The skilled person will appreciate that the deflector plate 28 may be formed by any suitable material allowing a sufficient stiffness of the guide portion 32.

P-KATCON-012/LU 10

[0034] The deflector plate presented Fig. 1 to Fig. 3 is made in one part by stamping. It also possible to form the deflector plate by embossing. The skilled person will appreciate that the deflector plate 28 may also be manufactured by assembly of multiple pieces, e.g. by attaching two separate flanges 34, 34’ to lateral portions of a plate forming the guide portion 32.

[0035] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustrations and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

P-KATCON-012/LU 11 List of Reference Symbols exhaust treatment assembly 12 housing 14 heat shield assembly 16 end cone 18 heat shield opening inlet port 22 mounting bracket 24 exposed surface 28 deflector plate

28.1 lower surface

28.2 upper surface

30.1 first extremity of deflector plate

30.2 second extremity of deflector plate 32 guide portion 34, 34' flange A first axis B second axis a inclination of the deflector plate

Claims

P-KATCON-012/LU 12 Claims

1. Exhaust treatment assembly comprising a housing and a heat shield assembly being arranged around said housing, said heat shield assembly comprising at least one heat shield opening through which at least one inlet port, which is arranged on and extending outwards from said housing, extends outward of said heat shield assembly; wherein said heat shield opening is dimensioned so that a circumferential gap is formed between said heat shield assembly and the at least one inlet port; characterized by a deflector plate, wherein said deflector plate is arranged outside said heat shield assembly and comprises a guide portion and two lateral portions, each one of the guide portion and the lateral portions extending from a first extremity of the deflector plate arranged near said at least one inlet port to a second extremity of the deflector plate, wherein the guide portion is substantially plane and each one of the lateral portions forms a flange extending from said guide portion in an upwardly, outward direction from the guide portion so that an angle is formed between the guide portion and a lateral portion, the angle being smaller than 180°, preferably the angle is comprised between 120° and 60°, and wherein the guide portion is configured to collect a liquid leaking near said at least one inlet port.

2. Exhaust treatment assembly according to claim 1, wherein the deflector plate is arranged outside the heat shield assembly so that a gap is formed between the heat shield assembly and the deflector plate, and wherein the gap has a height in the range between 0.5 mm and 10 mm.

3. Exhaust treatment assembly according to claim 1 or 2, wherein the first extremity of the deflector plate is formed to partially encompass the inlet port.

4. Exhaust treatment assembly according to any one of the preceding claims, wherein the inlet port extends outward from the housing along a first axis and wherein the deflector plate substantially extends along a second axis from the first extremity to the second extremity, the second axis forming an angle with the first axis.

P-KATCON-012/LU 13

5. Exhaust treatment assembly according to claim 4, wherein the angle between the first axis and the second axis is comprised between 10° and 170°, preferably 60° and 120°, most preferably between 80° and 100°.

6. Exhaust treatment assembly according to any one of the preceding claims, wherein the deflector plate is made of ferritic steel.

7. Exhaust treatment assembly according to any one of the preceding claims, wherein the deflector plate has a thickness in the range between 0.5 mm and mm.

8. Exhaust treatment assembly according to any one of the preceding claims, 10 wherein the deflector plate is made by stamping.

9. Exhaust treatment assembly according to any one of the preceding claims, wherein the heat shield assembly comprises a second heat shield opening through which at least one mounting bracket, which is arranged on and extending outwards from the housing, extends outward of the heat shield assembly, said second heat shield opening being dimensioned so that a circumferential gap is formed between said heat shield assembly and the at least one mounting bracket, said at least one mounting bracket being arranged near the at least one inlet port.

10. Exhaust treatment assembly according to claim 9, wherein the deflector plate is integrated with the at least one mounting bracket.

11. Exhaust treatment assembly according to claim 9 or 10, wherein the deflector plate is welded on or brazed to the mounting bracket, preferably the flanges of the deflector plates are welded on or brazed to the mounting bracket.

12. Exhaust treatment assembly according to any one of the preceding claims, wherein the inlet port is configured to accommodate a sensor device.

13. Exhaust treatment assembly according to any one of the preceding claims, wherein the inlet port is configured to accommodate a urea injection device.