WO2018206120A1

WO2018206120A1 - An exhaust gas system

Info

Publication number: WO2018206120A1
Application number: PCT/EP2017/061457
Authority: WO
Inventors: Guido Hanel
Original assignee: Volvo Construction Equipment Ab
Priority date: 2017-05-12
Filing date: 2017-05-12
Publication date: 2018-11-15
Also published as: CN110582623A; EP3622165A1; EP3622165B1; CN110582623B

Abstract

The present disclosure relates to an exhaust gas system (1, 1') for conveying exhaust gas from an engine (2, 2') to the ambient (3, 3'). The exhaust gas system (1, 1') has an exhaust pipe (10, 10') and a tail pipe (20, 20') wherein the tail pipe (20, 20') is disposed downstream the exhaust pipe (10, 10'). The tail pipe (20, 20') in use is tiltable between a first raised position (A) and a second tilted position (B) such that the tail pipe (20, 20') in both the first raised position (A) and the second tilted position (B) is adapted to convey exhaust gas there through. An air inlet (30, 30') is provided between the exhaust pipe (10) and the tail pipe (20, 20'), and an exhaust gas conveyor (40, 40') is located such that in the second tilted position (B) the exhaust gas conveyor (40, 40') conveys exhaust gas from the exhaust pipe (10, 10') to the tail pipe (20, 20') past the air inlet (30, 30'). The present disclosure further relates to an engine (2, 2') and a vehicle (4, 4') having such an exhaust gas system (1' 1').

Description

An exhaust gas system

TECHNICAL FIELD

The present disclosure relates to an exhaust gas system for conveying exhaust gas from an engine to the ambient, the exhaust gas system having an exhaust pipe and a tail pipe wherein the tail pipe is disposed downstream the exhaust pipe, the tail pipe in use being tiltable between a first raised position and a second tilted position such that the tail pipe in both the first raised position and the second tilted position is adapted to convey exhaust gas there through. The present disclosure further relates to an engine and a vehicle having such an exhaust gas system.

BACKGROUND

The invention is applicable on working machines within the fields of industrial construction machines or construction equipment, in particular pavers. Although the invention will be described with respect to a paver, the invention is not restricted to this particular machine, but may also be used in other working machines such as articulated haulers, excavators and backhoe loaders.

Existing pavers have a tiltable weather roof to which a likewise tiltable tail pipe is connected through e.g. a holding arm. In the normal operating position the tail pipe is located in an upright or vertical position. In the tilted position the tail pipe is located in a forwardly tilted and almost horizontally located position, 'forwardly' in this respect meaning pointing forwardly in the direction of forward driving of the paver. One reason for tilting the weather roof and the tail pipe is to reduce the height of the paver during transportation. Such transportation generally takes place through placing the paver on the back of a trailer. The paver is itself not made for long distance transportation at a speed of any relevance for such transportation. During a period when the weather roof and the tail pipe is tilted, the engine of the paver may have to be running, such that the tail pipe need to be operable also during this position.

Due to the need for proper function of the tail pipe in both its upright and tilted position present day pavers are equipped with a tiltable tail pipe which is connected in a generally gas tight manner to the exhaust pipe which distributes the exhaust gases from the engine. The transition between the exhaust pipe and the tail pipe is designed in the form of a large hinge, which hinge also conveys the exhaust gases with the aim to do so without applying any undue gas transportation restriction in the area. SUMMARY

An object of the present disclosure is to provide an exhaust gas system, which has an improved design while maintaining functionality with respect to tiltability and gas distribution. The object is achieved by a system according to claim 1 . This object is hence achieved by an exhaust gas system for conveying exhaust gas from an engine to the ambient, in which the exhaust gas system has an exhaust pipe and a tail pipe wherein the tail pipe is disposed downstream the exhaust pipe, the tail pipe in use being tiltable between a first raised position and a second tilted position such that the tail pipe in both the first raised position and the second tilted position is adapted to convey exhaust gas there through, wherein an air inlet is provided between the exhaust pipe and the tail pipe, and in that an exhaust gas conveyor is located such that in the second tilted position the exhaust gas conveyor conveys exhaust gas from the exhaust pipe to the tail pipe past the air inlet. This is a simple yet convenient and functional design which both enables air to enter into the tail pipe for cooling the exhaust gases which passes there through, while maintaining the gas conveying functionality. In the first raised position the tail pipe is conveying exhaust gases in a customary way, while in the second tilted position the exhaust gas conveyor is located such that it conveys the exhaust gases from the exhaust pipe to the tail pipe past the air inlet. Through this simple design a less complex and less bulky design is achieved.

The design is consequently cheaper than known designs. This design enables, if desirable, to generally completely separate the exhaust pipe from the tail pipe. It also enables removing the need for any seal between the exhaust pipe and the tail pipe. The disclosed system also enables to separate the hinge or tilting function from the exhaust gas conveying function. The hinge may be separate from an exhaust gas conveying path through the exhaust pipe and the tail pipe. The tilting point may also be separated from the exhaust pipe and the tail pipe. It also enables a minimising of any restricting effect on the exhaust gas transportation at the transfer between the exhaust pipe and the tail pipe. According to an embodiment the exhaust gas conveyor is part of the tail pipe at an inlet end thereof, and the exhaust gas conveyor is protruding towards the exhaust pipe such that, in the second tilted position, it is located vertically above an outlet end of the exhaust pipe. This is a simple yet efficient manner of achieving the object of the present disclosure. The exhaust gas conveyor functions as an umbrella or catcher for the exhaust gases when leaving the outlet end of the exhaust pipe and collects them in order to enter the inlet end of the tail pipe in the second tilted position. According to an embodiment the exhaust gas conveyor essentially covers the outlet of the outlet end of the exhaust pipe in the second tilted position. Normally the hot exhaust gases rise generally vertically when leaving the exhaust pipe. This way essentially all exhaust gases are caught by the exhaust gas conveyor and transferred into the tail pipe. According to an embodiment, in the first raised position, a contour of the inlet end of the tail pipe generally follows a contour of the outlet end of the exhaust pipe at a non-zero distance there from. Normally the hot exhaust gases rise generally vertically when leaving the exhaust pipe. This way essentially all exhaust gases are caught by the inlet end of the tail pipe and are transferred there into, while leaving a gap for air inlet.

According to an embodiment the air inlet extends along at least a majority of a circumference of the exhaust pipe and/or the tail pipe. Hereby enough air is allowed to enter into the tail pipe in order to enable cooling of the exhaust gases. According to an embodiment the air inlet is provided on a side of the exhaust gas system towards which the tail pipe is tiltable. The location of the air inlet is enabling a simplification of the tilting function owing at least in part to the open design and the related reduced amount of material in the tilting or folding area of the exhaust pipe - tail pipe interface. There is no longer a need for a gas tight transfer which simplifies the design.

According to an embodiment a hinge tiltably connects the exhaust pipe and the tail pipe. This hinge may be located at a position which is distant from the exhaust pipe - tail pipe interface, which could also be described as a transfer zone between the exhaust pipe and the tail pipe at the air inlet at which the exhaust gas conveyor conveys exhaust gas from the exhaust pipe to the tail pipe past the air inlet, and may thus be located in a position where it is better suited both from a vehicle design perspective and where it disturbs the exhaust gas transfer between the exhaust pipe and the tail pipe less.

According to an embodiment the hinge is located in the proximity of an inlet end of the tail pipe and in the proximity of an outlet end of the exhaust pipe. It is not necessary for such a hinge to be located exactly at the inlet end of the tail pipe or at the outlet end of the exhaust pipe, but may be located slightly distended there from to enable e.g. a tilting path of the tail pipe in relation to the exhaust pipe which is advantageous. According to an embodiment the exhaust pipe, in the proximity of an outlet end thereof, or the tail pipe, in the proximity of an inlet end thereof, is provided with a venturi system for entering ambient air in order to cool the exhaust gases flowing there through. The venturi system enables additional air to be introduced, e.g. into the tail pipe, for cooling of the exhaust gases. The venturi system ascertains an improved mixing between the air and the exhaust gases.

According to an embodiment the tail pipe in the proximity of an inlet end thereof is provided with a further air inlet system for entering ambient air in order to cool the exhaust gases flowing there through, wherein the further air inlet system preferably has a plurality of air inlet openings located transversely to an exhaust gas flow direction of the tail pipe. The further air inlet system enables additional air to be introduced, e.g. into the tail pipe, for cooling of the exhaust gases. The further air inlet system is preferably located at in inlet end of the tail pipe. According to an embodiment the exhaust pipe is protruding into the tail pipe in both the first raised position and the second tilted position. This is a simple yet efficient manner of achieving the object of the present disclosure. The exhaust pipe preferably has a smaller cross-sectional dimension than the tail pipe. This way the exhaust pipe may protrude into the tail pipe both providing room for air inlet there around, and maintaining a path transfer path from the exhaust pipe to the tail pipe in both the first raised position and the second tilted position.

According to an embodiment the exhaust pipe protrudes into the tail pipe past the further air inlet system. A proper mixing of air and exhaust gas may thus be achieved. According to an embodiment a cross sectional area of the tail pipe is larger than a cross sectional area of the exhaust pipe. This design enables that all or essentially all exhaust gases are transferred into the tail pipe. According to an embodiment the tail pipe is adapted to convey exhaust gas there through in any position between the first raised position and the second tilted position. It may at times be advantageous to be able to use the exhaust gas system also in any intermediate position. According to an embodiment an angle between the first raised position and the second tilted position is at least 30 degrees, preferably at least 45 degrees, and more preferably at least 60 degrees.

According to an embodiment the first raised position of the tail pipe being a generally vertical position and the second tilted position being a generally horizontal position. A generally vertical position of the tail pipe is a common position for an exhaust gas system of this kind, and a generally horizontal position enables a maximised lowering of height in e.g. a transportation state. According to an embodiment the outlet end of the exhaust pipe remains in its position in both the first raised position and the second tilted position of the tail pipe. The outlet end of the exhaust pipe is consequently easy to accommodate in a vehicle design without affecting such design negatively. According to an embodiment the tail pipe is an end section of the exhaust gas system, such that the exhaust gases leave the exhaust gas system and enters the ambient when exiting the tail pipe.

According to an embodiment the air inlet covers approximately 50 % of the circumference of the tail pipe, and consequently the exhaust gas conveyor covers approximately 50 % of the circumference of the tail pipe. The exhaust gas conveyor may cover between 25 to 75 % of the circumference of the tail pipe, preferably between 35 to 65 %, and more preferably between 40 to 60 % in order to catch and convey exhaust gases in an efficient manner. According to an embodiment the engine is an internal combustion engine. As such an internal combustion engines produces exhaust gases which needs transferring away for which the exhaust gas system may function well. According to an embodiment a vehicle is disclosed which comprises an exhaust gas system of the kind disclosed above.

According to an embodiment the vehicle is a construction equipment vehicle, such as a paver.

According to an embodiment the tail pipe is adapted to be tiltable together with a foldable part of the vehicle, such as a foldable weather roof.

According to an embodiment the tail pipe being hingely connected at or in the proximity of an outlet end thereof to the foldable part of the vehicle, such that the tail pipe and the foldable part are tilted together between the first raised position and the second tilted position.

Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detailed description of embodiments of the disclosure cited as examples.

In the drawings:

Fig. 1 a is side view a paver which is equipped with an exhaust gas system of the kind of the present disclosure in a first raised position,

Fig. 1 b is a view as in Fig. 1 a, with exhaust gas system in a second tilted position, Fig. 2 is an enlarged side view of an exhaust pipe - tail pipe interface of Fig. 1 a,

Fig. 3 is a perspective view of the Fig. 2 embodiment,

Fig. 4 is an enlarged side view of an exhaust pipe - tail pipe interface of Fig. 1 b,

Fig. 5 is a perspective view of an alternative exhaust gas system,

Fig. 6 is a perspective view of an exhaust gas system according to prior art, Fig. 7 is a is a side view of an exhaust pipe - tail pipe interface according to an alternative embodiment in a first raised position, and

Fig. 8 is a side view of the Fig. 7 embodiment in a second tilted position. DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE DISCLOSURE

Starting with the disclosure of Fig. 1 a, a paver 4 of generally known kind is shown, which is equipped with an exhaust gas system 1 of the kind disclosed herein. The exhaust gas system 1 is located in a raised, vertical position A which is the main working position A of the exhaust gas system 1 as well as of the paver 4. This position is henceforth called a first raised position A. In this position A exhaust gases from an engine 2 of the paver 4 are transferred through an exhaust pipe 10 and a tail pipe 20 before leaving the tail pipe to enter the ambient 3. The paver 4 may be equipped with additional equipment, such as an exhaust gas after treatment system for at least to some extent cleaning the exhaust gases before entering the ambient 3. Any such additional equipment is normally connected to the exhaust pipe 10 downstream of the engine 2 and upstream of the tail pipe 20, and is not the content of this disclosure and is hence also not shown in any drawings.

The paver 4 is equipped with a weather roof 5 which also is shown in its raised, generally vertical working position A. The weather roof 5 comprises in general terms four generally vertical uprights 6, one in each corner, which uprights 6 holds the roof 5 itself in position and which roof 5 is used to keep the driver of the paver 4 protected from sun and wind. The weather roof 5 is of a generally known kind and is also not the subject of the present disclosure. The tail pipe 20 is connected to the weather roof 5 through a holding arm 7. The holding arm 7 is rotationally connected to the weather roof 5 at one end and to the tail pipe 20 in an opposite end. The holding arm 7 is of a generally known kind and is not the subject of the present disclosure. The holding arm 7 maintains the first raised position A of the tail pipe 20 when the weather roof 5 is locked in its raised position which corresponds to the first raised position A of the tail pipe 20. When the weather roof 5 is tilted, to a lowered, second tilted position B, as shown in Fig. 1 b, the tail pipe 20 follows the movement of the weather roof 5 to its own second tilted position B. A reason for tilting the weather roof 5 and the tail pipe 20 is to lower the height of the paver during e.g. transportation of the paver on a trailer of a lorry. It should be noted that the paver 4 is adapted to be run also when having the weather roof 5 and tail pipe 20 in the second tilted position B, such that the engine 2 is producing exhaust gases which need to be transported away from the engine 2 and any person handling the paver 4. For clarity's sake, it is also noted that the exhaust gases which are produced in the engine 2 are conveyed from the engine 2, through the exhaust pipe 10, into the tail pipe 20 and out into the ambient 3.

The engine 2 is an internal combustion engine, of preferably petrol or diesel type, although any type of exhaust gas producing engine 2 for any type of fuel is contemplated.

The exhaust gas system 1 of the present disclosure may be used with other types of vehicles 4, such as for any type of construction equipment or other vehicle type.

In Fig. 2, the exhaust gas system 1 is shown in greater detail. The figure is a cut-out and enlargement of the area in Fig. 1 a around the exhaust pipe - tail pipe interface. What is shown is a bonnet 8 of the paver 4, which covers and protects the engine 2 (as shown in Figs. 1 a and 1 b) and which also may be designed to give the paver 4 an appealing design. The bonnet 8 is provided with a hole 9 for the exhaust gas system 1 to protrude from the engine 2 into the ambient 3. As can be gleaned the exhaust pipe 10 is connected to an exhaust gas manifold which is part of the engine 2, and is given an appropriate curvature to have an outlet end 1 1 thereof in a generally vertical position which extends through the hole 9 through the bonnet 8. The outlet end 1 1 has an outlet 12 which is an opening through which exhaust gases may pass. The outlet end 1 1 of the exhaust pipe 10 terminates generally in a plane corresponding to a plane of the bonnet 8 at the hole 9. The bonnet 8 is slanting in a forward direction of the paver 4. In the depicted embodiment the outlet end 1 1 of the exhaust pipe 10 is also slanting with an angle corresponding generally to an angle of slant of the bonnet 8. This may be designed otherwise, such as for example having a horizontal bonnet 8 with an outlet end 1 1 of the exhaust pipe 10 also being horizontally located. The edges of the outlet end 1 1 of the exhaust pipe 10 may also be designed not to conform to the precise angle of slant or other design of the bonnet 8 and of the hole 9. The hole 9 through the bonnet 8 is larger than an outer perimeter of the exhaust gas system 1 .

Generally vertically above the outlet end 1 1 of the exhaust pipe 10 an inlet end 21 of the tail pipe 20 is located. The hot exhaust gases are consequently rising through the outlet end 1 1 of the exhaust pipe 10 into the inlet end 21 of the tail pipe 20 during use of the paver 4, i.e. during running of the engine 2. The exhaust pipe 10 has a rounded, generally circular, cross-section and the tail pipe 20 has a polygonal cross-section of a generally rectangular main shape. The cross-sectional area of the tail pipe 20 is larger than the cross-sectional area of the exhaust pipe 10. The tail pipe 20 is also larger than the exhaust pipe 10 as seen in a horizontal plane, such that the inlet end 21 of the tail pipe 20 5 is able to catch and convey generally all of the exhaust gases coming from the engine 2, even though there might be a side wind blowing around the paver 4. The tail pipe 20 and the exhaust pipe 10 each has an axial centre axis, and the location and direction of the centre axis of the tail pipe 20 corresponds generally to the location and direction of the centre axis of the exhaust pipe 10 at the exhaust pipe - tail pipe interface. The curvature

10 of the exhaust pipe 10 between the engine 2 and its outlet end 1 1 may be of any design to bridge the gap between the engine 2 and the exhaust pipe - tail pipe interface. The tail pipe 20 may be located in the paver 4 such that it is close to the engine 2, while not blocking the view for the driver of the paver 4. Hence the general curvature of the exhaust pipe 10 is adapted to the current location of the engine 2 and inlet end 21 of the tail pipe

15 20 respectively.

The tail pipe 20 is a separate item from the exhaust pipe 10. This means that although the exhaust pipe 10 and the tail pipe 20 are located close to one another, they are not made in one piece. There is a non-zero distance in the form of an air inlet 30 between the outlet

20 end 1 1 of the exhaust pipe 10 and the inlet end 21 of the tail pipe 20. Approximately half of a circumference of the inlet end 21 of the tail pipe 20 is located at approximately 1 cm or more vertically above the bonnet 8 for ambient air to enter into the tail pipe 20 and to cool the hot exhaust gases during use. The distance could be either smaller or larger. It can also have a curved opening, such as in the later disclosed second embodiment. The

25 distance between the outlet end 1 1 of the exhaust pipe 10 and the inlet end 21 of the tail pipe 20 could also be located underneath the bonnet 8. The particular design depends on how much ambient air is desirable for the cooling function of the exhaust gases and from where the major part of the ambient air should be drawn. The distance is between at least 0.5 and 5 cm, and preferably between at least 1 and 5 cm. The air inlet 30 is located in

30 the tail pipe 20 in a forward direction of the paver 4 to collect ambient air. The design of the tail pipe 20 on its opposite side, which side is not shown here, is generally similar to the one shown, such that the tail pipe 20 is symmetrical along its axial extension.

The tail pipe 20 is tiltably connected by a bolt 50 to the paver 4. The bolt 50 represents a 35 hinge 50 and any kind of hinge joint may be used as an alternative for the bolt 50. The bolt 50 connects the tail pipe 20 to a beam 60 of the paver 4, which beam 60 is rigidly mounted underneath the bonnet 8 for i.a. maintaining the tail pipe 20 in position. The tail pipe 20 is hence adapted to be tilted or rotated around the bolt 50 between its first raised position A and its second tilted position B. Depending on the location of the bolt 50 in relation to the tail pipe 20 different paths may be achieved. In the present embodiment the tail pipe 20 is provided with a U-shaped lever 41 at a distance from the inlet end 21 of the tail pipe 20, and the bolt 50 is located in a direction which is transverse to the forward direction of the paver 4, such that the tail pipe 20 is tilted generally forwardly. The U- shaped lever 41 is shaped as a U as seen in cross-section of the tail pipe 20. Another advantage gained by the distance between the tilting point, i.e. the location of the bolt 50 in relation to the inlet end 21 of the tail pipe 20, and the inlet end 21 of the tail pipe 20, is that the parts of the inlet end 21 of the tail pipe 20 are configured not to interfere with the bonnet 8 or the outlet end 1 1 of the exhaust pipe 10. The location of the tilting point may also be set more freely in comparison to the known exhaust gas systems, in which the tilting point is a part of the exhaust gas pathway. The tilting point is hence separated from the exhaust pipe 10 and the tail pipe 10. In the present embodiment the tilting point is located in front of the air inlet 30 at the exhaust pipe - tail pipe interface.

It should be noted that the outlet end 1 1 of the exhaust pipe 10 is generally fixed in location in relation to the paver 4. This means that the relative motion between the outlet end 1 1 of the exhaust pipe 10 and the inlet end 21 of the tail pipe 20 is solely provided by the tilting motion of the inlet end 21 of the tail pipe 20.

As can be gleaned from Fig. 2 the inlet end 21 of the tail pipe 20 is provided with an exhaust gas conveyor 40. The exhaust gas conveyor 40 is in the present embodiment designed as a tongue which protrudes from the inlet end 21 of the tail pipe 20 in a direction vertically downwards, and away from the remainder of the tail pipe 20. The exhaust gas conveyor 40 consequently extends in an axial direction of the tail pipe 20. The U-shaped lever 41 is fastened to the lowermost point of the exhaust gas conveyor 40, when the tail pipe 20 is in its first raised position A. The lever 41 may be made in one piece with the exhaust gas conveyor 40 and the tail pipe 20, or may be a separate item which is later fastened thereto. Also the exhaust gas conveyor 40 may preferably be made in one piece with the remainder of the tail pipe 20, but may alternatively be made as a separate item which is fastened to the tail pipe 20. The exhaust gas conveyor 40 encloses the outlet end 1 1 of the exhaust pipe 10 fully at an aft end of the exhaust pipe 10, but not fully alongside the exhaust pipe 10, as seen in a forward direction of the paver 4. The width of the exhaust gas conveyor 40 as seen in a circumferential direction of the tail pipe 20 is generally a balance between a large enough air inlet 30 and a large enough exhaust gas conveyor 40. In the present embodiment the air inlet 30 covers slightly less than 50 % of the circumference of the tail pipe 20, and consequently the exhaust gas conveyor 40 covers slightly more than 50 % of the circumference of the tail pipe 20. It is contemplated that the exhaust gas conveyor 40 preferably should cover between 25 to 75 %, more preferably between 35 to 65 %, and most preferably between 40 to 60 % in order to catch and convey exhaust gases in an efficient manner.

In Fig. 3 the embodiment of Fig. 2 is shown in perspective view, including the full length of the tail pipe 20. The exhaust gas system 1 is shown in its first raised position A. The tail pipe 20 is at its vertical top portion designed in a known manner and this is not discussed further herein.

In the first raised position A of the tail pipe 20, the exhaust gas conveyor 40 is not, or at least generally not, used for any conveying action of exhaust gases since the location of the inlet end 21 of the tail pipe 20 in relation to the outlet end 1 1 of the exhaust pipe 10 serves this purpose, but as may be gleaned from Fig. 4, it is used in the second tilted position B for collecting and conveying exhaust gases from the exhaust pipe 10 into the tail pipe 20. Since the hot exhaust gases rise upwards, they meet the exhaust gas conveyor 40 and are conveyed into the tail pipe 20. In this second tilted position B, the exhaust gas conveyor 40 is thus located vertically above the outlet end 1 1 of the exhaust pipe 10. The exhaust gas conveyor 40 even covers the outlet 12 of the outlet end 1 1 of the exhaust pipe 10 in the second tilted position B to catch and convey all exhaust gases from the exhaust pipe 10. From Fig. 4 it may be gleaned that the exhaust gas conveyor 40 has a small overlap with the outlet end 1 1 . The overlap is an overlap as seen in the side view of Fig. 4. The reason for the existence of an overlap is to convey all exhaust gases, but if it is acceptable to convey a slightly reduced ratio of the exhaust gases, or if a design other than an overlap is found advantageous, another design may be conceivable. Such other design may include an exhaust gas conveyor 40 which protrudes in the axial direction of the tail pipe 20 with the same curvature as the tail pipe 20. When the tail pipe 20 is in this second tilted B position it may at its forward front of the air inlet 30 abut the bonnet 8 of the paver 4. The shape of the air inlet 30 is however such that there are still open areas remaining at the sides of the air inlet 30 in relation to the tail pipe 20 walls, such that ambient air may enter. The shape of the air inlet 30 may however be otherwise designed. In the present embodiment the design is mainly made to conform to the design of the bonnet 8 when positioned in the first raised position A, and to bridge the distance to the exhaust gas conveyor 40 and the lever 41 to hold the tail pipe 20 in place. In Fig. 5 an alternative embodiment of the present disclosure is disclosed in which the exhaust pipe - tail pipe interface of the above disclosed type is used, but for which a further air inlet system 31 has been added at the lower parts of the tail pipe 20. This further air inlet system 31 take for form of a plurality of air inlet openings 31 a, 31 b located transversely to an exhaust gas flowing direction of the tail pipe 20. This further air inlet system 31 may be used with the other embodiments of the exhaust pipe - tail pipe interface disclosed herein, such as the one disclosed with reference to Figs. 7 - 8 below. The tail pipe 20 or the exhaust pipe 10 may also be provided with a venturi system (not shown), such as in the proximity of the inlet end 21 or at the outlet end 1 1 , respectively, at the inside in order to improve mixing of exhaust gases and ambient air. A venturi system may take the form of decrease in diameter over a short axial extension of the tail pipe 20 or the exhaust pipe 10. The predominant diameter is then reset, downstream the venturi system.

Fig. 6 shows an exhaust gas transportation system 1 PA according to prior art for comparison with the present disclosure. The exhaust gas pathway is indicated through arrows through the system. Exhaust gases are flowing from an engine up in an exhaust conduit 10PA which protrudes through a gap in a bonnet 8PA. Vertically above the bonnet 8PA a large hinge joint 50PA is located which serves the dual purposes of conveying exhaust gases and providing a tilting function for the system 1 PA. Beyond that it is also gas tight. The exhaust gases are thereafter transported out into the ambient 3 and released at a vertically higher level. This is a complex and expensive structure which e.g. high demands on production tolerances.

The hinge joint 50PA takes for form of a cylinder which is divided around its middle part into two generally symmetrical halves 52PA, 53PA, which halves 52PA, 53PA are joined together for relative rotational motion. The joint 51 PA is sealed to avoid any gas leakage. The hinge joint 50PA adds a restriction for the gas flow path.

The attention is now turned towards Fig. 7 and an alternative embodiment of the present disclosure. Like details are given like numbers in relation to the embodiment disclosed above. This embodiment includes an exhaust gas system 1 ' having an exhaust pipe 10' and a tail pipe 20'. The exhaust pipe 10' is in this embodiment protruding through the hole 9' in the bonnet 8' of the paver 4'. The exhaust pipe 10' is in this embodiment furthermore protruding slightly into the tail pipe 20'. There is hence a slight overlap between the outlet end 1 1 ' of the exhaust pipe 10' and the inlet end 21 ' of the tail pipe 20'. The protrusion length of the outlet end 1 1 ' of the exhaust pipe 10' into the inlet end 21 ' of the tail pipe 20' may be chosen to be longer than what is depicted in Fig. 7. An air inlet 30' is provided in a forward direction of the inlet end 21 ' of the tail pipe 20'. The outlet end 1 1 ' of the exhaust pipe 10' is open in its vertical top portion for conveying the exhaust gases. The vertically seen lowermost part of the tail pipe 20' is provided with an exhaust gas conveyor 40' for catching and conveying the exhaust gases from the exhaust pipe 10' into the tail pipe 20' past the air inlet 30' in the second tilted position B.

In the Fig. 7 embodiment a hinge having a bolt 50' for holding and tilting the tail pipe 20' is located behind the outlet end 1 1 ' of the exhaust pipe 10' as seen in a forward direction of the paver 4'. This location may be used with any embodiment of the present exhaust gas system herein. The location is chosen in the present embodiment since the tilting of the tail pipe 20' is not hindered by the location of the exhaust pipe 10', and the air inlet 30' is sized to accommodate the outlet end 1 1 ' of the exhaust pipe 10' in the second tilted position B, which is shown in Fig. 8.

The upper parts of the tail pipe 20' may in this embodiment conform to any one of the embodiments earlier described herein. The lower part of the exhaust gas conveyor 40', is closed, not only in the lateral surface of the tail pipe 20', but also in the portion starting from the hinge 50' and going backwards as seen in the forward direction of the paver 4', i.e. the portion which in the first raised position A of the exhaust gas system 1 ' is facing the bonnet 8' and the paver 4', and which in the second tilted position B is located such that catches and conveys the exhaust gases from the exhaust pipe 10' into the tail pipe 20'. The closed surface portion together with lateral surfaces of the tail pipe 20' in this area, i.e. the size and configuration of the exhaust gas conveyor 40', should at least be such that it is adapted in use of the exhaust gas system 1 ' to in the second tilted position B convey exhaust gas from the exhaust pipe 10' to the tail pipe 20' past the air inlet 30'. It may be said that the exhaust gas conveyor 1 ' essentially covers the outlet 12 of the outlet end 1 1 ' of the exhaust pipe 10' in the second tilted position B. For this reason it may not be necessary to have a surface closed all down to the hinge 50', since the outlet end 1 1 ' of the exhaust pipe 10' is located well above this point in the present embodiment.

In all of the above disclosed embodiments the first raised position A of the tail pipe 10, 10' is either vertical or almost vertical, i.e. approximately at an angle of between 0 and 15 degrees to the vertical. The angle of the tail pipe 10, 10' to the vertical may however be slightly larger if desired. The second tilted position B of the tail pipe 10, 10' could be almost horizontal if desired, but is in the depicted embodiments at an angle between the first raised position A and the second tilted position B of approximately 45 degrees. It is contemplated that said angle could be between at least 30 degrees and at least 60 degrees, within which range the height of the paver 4, 4' is low enough to e.g. conform to any transportation heights requirements.

It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims. Such changes may involve the use of the exhaust gas system without the accompanying weather roof which is disclosed above. The tail pipe may e.g. be equipped with its own locking mechanism to maintain the first raised position, and for releasing to lower it to the second tilted position.

The size and shape of the exhaust pipe as well as of the tail pipe may be designed differently than what is disclosed above. The exhaust pipe may be given any shape, such as polygonal, and the tail pipe may also be designed differently, such as having a rounded design. Their mutual cross-sectional dimensions may also be different, such as having equal cross-sectional area. The tail pipe may also be designed to accommodate more than one exhaust pipe, or to accommodate one exhaust pipe and additional pipes, such as one conveying bituminous gases from the aft parts of the paver during use thereof. Such additional gases, such as the bituminous ones, may also be mixed with ambient air in order to cool them down and to dilute them. The pipes could preferably be located alongside one another as seen in a forward direction of the paver, but other designs could also be used. It is contemplated to have all pipes entering gases into the inlet end of the tail pipe of rectangular design to keep the total cross-sectional side low. The size of the inlet end of the tail pipe consequently needs to be adapted to the number of pipes to catch and convey gases from. Another option would be to add any additional gas upstream the outlet end of the exhaust pipe in order to only have one pipe meeting the tail pipe at the exhaust pipe - tail pipe interface. It is further contemplated to adapt the exhaust gas system to convey machine compartment air into the tail pipe. A proper ventilation of the engine compartment may thus be achieved. Another embodiment could be some other location of the tilting point of the exhaust pipe - tail pipe interface. It may be positioned wholly behind the exhaust pipe - tail pipe interface as seen in the forward direction of the paver, but also at a location alongside the exhaust pipe - tail pipe interface if desirable. It is contemplated that the relative motion between the outlet end of the exhaust pipe and the inlet end of the tail pipe could be achieved through a combined motion of the outlet end of the exhaust pipe and the inlet end of the tail pipe relative to one another. A prerequisite is however that the exhaust gas conveyor in the second tilted position is adapted to convey exhaust gases from the exhaust pipe to the tail pipe past the air inlet. Although not specifically requested, all of the above embodiments of the exhaust gas system may be used to convey exhaust gas in any position between the first raised position and the second tilted position from the exhaust pipe to the tail pipe past the air inlet. The design, location and specific type of hinge, lever and bolt may be altered. The bolt may e.g. be exchanged for any type of general fastening means which achieves a rotational motion of the tail pipe.

Claims

1 . An exhaust gas system (1 , 1 ') for conveying exhaust gas from an engine (2, 2') to the ambient (3), the exhaust gas system (1 , 1 ') having an exhaust pipe (10, 10') and a tail pipe (20, 20') wherein the tail pipe (20, 20') is disposed downstream the exhaust pipe (10, 10'), the tail pipe (20, 20') in use being tiltable between a first raised position (A) and a second tilted position (B) such that the tail pipe (20, 20') in both the first raised position (A) and the second tilted position (B) is adapted to convey exhaust gas there through, characterized in that an air inlet (30, 30') is provided between the exhaust pipe (10, 10') and the tail pipe (20, 20'), and in that an exhaust gas conveyor (40, 40') is located such that in the second tilted position (B) the exhaust gas conveyor (40, 40') conveys exhaust gas from the exhaust pipe (10, 10') to the tail pipe (20, 20') past the air inlet (30, 30').

2. An exhaust gas system (1 , 1 ') according to claim 1 , wherein the exhaust gas conveyor (40, 40') is part of the tail pipe (20, 20') at an inlet end (21 , 21 ') thereof, and the exhaust gas conveyor (40, 40') is protruding towards the exhaust pipe (20, 20') such that, in the second tilted position (B), it is located vertically above an outlet end (1 1 , 1 1 ') of the exhaust pipe (10, 10').

3. An exhaust gas system (1 , 1 ') according to claim 2, wherein the exhaust gas conveyor (40, 40') essentially covers an outlet (12) of the outlet end (1 1 , 1 1 ') of the exhaust pipe (10, 10') in the second tilted position (B).

4. An exhaust gas system (1 , 1 ') according to any one of the claims 2 to 3, wherein, in the first raised position (A), a contour of the inlet end (21 , 21 ') of the tail pipe (20, 20') generally follows a contour of the outlet end (1 1 , 1 1 ') of the exhaust pipe (10, 10') at a non-zero distance there from.

5. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein the air inlet (30, 30') extends along at least a majority of a circumference of the exhaust pipe (10, 10') and/or the tail pipe (20, 20').

6. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein the air inlet (30, 30') is provided on a side of the exhaust gas system (1 , 1 ') towards which the tail pipe (20, 20') is tiltable.

7. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein a hinge (50, 50') tiltably connects the exhaust pipe (10, 10') and the tail pipe (20, 20').

8. An exhaust gas system (1 , 1 ') according to claim 7, wherein the hinge (50, 50') is located in the proximity of an inlet end (21 , 21 ') of the tail pipe (20, 20') and in the proximity of an outlet end (1 1 , 1 1 ') of the exhaust pipe (10, 10').

9. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein the exhaust pipe (10, 10'), in the proximity of an outlet end (1 1 , 1 1 ') thereof, or the tail pipe (20, 20'), in the proximity of an inlet end (21 , 21 ') thereof, is provided with a venturi system for entering ambient air in order to cool the exhaust gases flowing there through.

10. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein the tail pipe (20, 20') in the proximity of an inlet end (21 , 21 ') thereof is provided with a further air inlet system (31 ) for entering ambient air in order to cool the exhaust gases flowing there through.

1 1 . An exhaust gas system (1 , 1 ') according to claim 10, wherein the further air inlet system (31 ) has a plurality of air inlet openings (31 a, 31 b) located transversely to an exhaust gas flowing direction of the tail pipe (20, 20').

12. An exhaust gas system (1 ') according to any one of the preceding claims, wherein the exhaust pipe (10') is protruding into the tail pipe (20') in both the first raised position (A) and the second tilted position (B).

13. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein a cross sectional area of the tail pipe (20, 20') is larger than a cross sectional area of the exhaust pipe (10, 10').

14. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein the tail pipe (20, 20') is adapted to convey exhaust gas there through in any position between the first raised position (A) and the second tilted position (B).

15. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein an angle between the first raised position (A) and the second tilted position (B) is at least 30 degrees, preferably at least 45 degrees, and more preferably at least 60 degrees.

16. An exhaust gas system (1 , 1 ') according to claim 15, wherein the first raised position (A) of the tail pipe (20, 20') being a generally vertical position and the second tilted position (B) being a generally horizontal position.

17. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, wherein the outlet end (1 1 , 1 1 ') of the exhaust pipe (10, 10') remains in its position in both the first raised position (A) and the second tilted position (B) of the tail pipe (20, 20').

18. An exhaust gas system (1 , 1 ') according to any one of the preceding claims, 5 wherein the tail pipe (20, 20') is an end section of the exhaust gas system (1 , 1 '), such that the exhaust gases leave the exhaust gas system (1 , 1 ') and enters the ambient (3) when exiting the tail pipe (20, 20').

19. An engine (2, 2') comprising an exhaust gas system (1 , 1 ') according to any one of the preceding claims, the engine (2, 2') preferably being an internal combustion engine.

10 20. A vehicle (4, 4') comprising an exhaust gas system (1 , 1 ') according to any one of claims 1 to 17.

21 . A vehicle (4, 4') according to claim 20, wherein the vehicle (4, 4') is a construction equipment vehicle, such as a paver.

22. A vehicle (4, 4') according to any one of claims 20 to 21 , wherein the tail pipe (20, 15 20') is adapted to be tiltable together with a foldable part (5) of the vehicle (4, 4'), such as a foldable weather roof.

23. A vehicle (4, 4') according to claim 22, wherein the tail pipe (20, 20') being hingely connected at or in the proximity of an outlet end thereof to the foldable part (5) of the vehicle (4, 4'), such that the tail pipe (20, 20') and the foldable part (5) are tilted together

20 between the first raised position (A) and the second tilted position (B).