GB2524225A

GB2524225A - Vehicle

Info

Publication number: GB2524225A
Application number: GB1400675.3A
Authority: GB
Inventors: Denis Joseph Culloty; Marc Ian Harrison
Original assignee: Leyland Trucks Ltd
Current assignee: Leyland Trucks Ltd
Priority date: 2014-01-15
Filing date: 2014-01-15
Publication date: 2015-09-23
Anticipated expiration: 2034-01-15
Also published as: GB2524225B; GB201400675D0

Abstract

A vertically extending exhaust pipe 2 of a vehicle is fitted at an upper outlet section with an exhaust gas outlet arrangement 1 which inhibits passage of water into the exhaust pipe, whilst allowing discharge of exhaust gas. The outlet arrangement includes a water trap unit 3 comprised of a vertically extending first (outlet) tubular member 6 axially off-set from the upper section of the exhaust pipe, the first tubular member having an aperture in the wall thereof above the lower end of the first tubular member. A second (bridging) tubular member 7 extends transversely to said first tubular member from said aperture thereof to provide communication between the first tubular member and the upper section of the exhaust pipe. Within the first tubular member, the aperture is shielded by a ledge (12, figure 2) to inhibit passage of water into the second tubular member. The first tubular member has a water outlet (11, figure 2) below the level of the ledge.

Description

Vehicle The present invention relates to a vehicle having an exhaust pipe with protection against the ingress of water into the exhaust pipe. The invention relates more particularly (but not exclusively) to trucks in which it is necessary to prevent passage of water into and along the exhaust to ensure protection of a component such as a Selective Catalytic Reduction (SCR) unt, a NO, sensor or a Diesel Particulate Filter (D P F).

Combustion of diesel fuel by trucks produces mixtures of gaseous products including carbon monoxide, carbon dioxide and nitrous oxides (NOx); and particulate matter in the form of particulate carbon. Certain of these products are damaging to the environment and/or hazardous to health and so legislation (e.g. the Euro 5 and Euro S standards in Europe) requires trucks to include systems of either chemically converting combustion products into less damaging/hazardous substances before exiting the truck via exhaust pipework, or physically removing combustion products (e.g. particulate carbon) before exhaust discharge.

NOx is typically converted into nitrogen and water using a selective catalytic reduction (SCR) unit, which catalyses a reduction reaction between NOx and urea.

The amount of urea reqthred by the SCA depends on the amount of NOx in the combustion gases. A NOx sensor is therefore provided n order to measure the leves of NOx and thus the ev& of urea required. The NOx sensor is operatively inked with a urea injection system so that the amount of urea njected in the SCR can be adjusted, as necessary, depending on the amount of NOx detected ri the combustion gasses.

Particuate carbon may be physicaIy removed u&ng a DeseE ParficuPats FUter (DPF) which traps particuate matter n a fflter, and which may be adapted periodicafly to burn off the matter which accumulates.

The effectiveness of the SOR unit, the NOx sensor and the DPF can be adverse'y affected by exposure to water. Trucks are exposed to water from a vat ety of sources, such as from rain, traffic--generated spray and aso dudng routine truck cleaning.

Passage of water to the SCA unit, NOx sensor and DPF s particularly a problem fl the case of trucks having a verticafly extending exhaust pipe with an upper exhaust oufiet.

In this case, water can pass into and down the exhaust pipe and reach the 5CR unft, NOx sensor or DPF.

In order to prevent water entenng the exhaust pipe, trucks may be provided with a fixed exhaust rain cap to shield the open end of exhaust pipework. Such caps are designed to shield the open end of the exhaust from water ingress, while simultaneously allowing exhaust gases to escape. Undesirably, however, the cap presents an obstruction to gas flow and hence increases back pressure within the exhaust, impacting engine efficiency.

To ameliorate the problem of exhaust back pressure, exhaust rain caps may be of hinged design so as to be able to pivot to an open position upon action of exhaust gases exiting the exhaust. When in an open position, the cap does not obstruct gas flow and hence no increase in back pressure occurs. Gases are released from the exhaust under relatively high flow rate and so, when the cap is in the open position, the gas flow prevents water from entering the exhaust. Hinged capping. systems are typically biased towards a closed position so that the cap closes once exhaust gas flow stops, thus one again shielding the open end of the exhaust mom water ingress.

However, hinged capping systems suffer from a disadvantage that the hinge can be easily damaged. This may cause the cap to become permanently open, thus compromising its water shielding function.

The design of capping systems often means that they are incompatible with fittings which may be provided on the end of exhaust pipework, Such fittings may provide a variety of useful functions, for example causing the flow of exhaust gas leaving the exhaust pipework to diverge and so cool down. It is, therefore, desirable for capping systems to be compatible with such fittings.

It is therefore an object of the invention to obviate or mitigate the abovementioned disadvantages.

According to a first aspect of the present invention there is provided a vehicle having an exhaust pipe with a vertically extending upper section at the upper end of which is the outlet of the exhaust pipe, said exhaust pipe being fitted at its upper outlet end with an exhaust gas arrangement which inhibits passage of water from external of the vehicle into the exhaust pipe whilst providing passage of exhaust gas to the atmosphere through the arrangement, wherein said outlet arrangement includes a water trap unit comprised of a vertically extending first tubular member axially off-set from the upper section of the exhaust pipe, said first tubular member having an aperture in the wall thereof above the lower end of said tubular member, and a second tubular member extending transversely to said first tubular member from said aperture thereof to provide communication between the interiors of said first tubular member and the upper section of the exhaust pipe wherein within the first tubular member said aperture is shielded by a ledge to inhibit passage of water into said second tubular member and wherein the first tubular member has a water outlet below the level of the ledge.

The water trap unit inhibits the passage of water to the exhaust pipe so that any upstream component such as an SCR unit, NO, sensor or DPF is prevented from water damage. More specifically, any water (such as from rain, traffic-generated spray or vehicle wash water) that enters the first tubular member is captured therein and discharged harmlessly through the outlet thereof. More specifically, water that runs down the inner wall of the first tubular member towards the aperture is prevented from passage into the aperture by virtue of the ledge which effectively diverts that water past the aperture, allowing it to be drained through the outlet. Other water that enters the upper region of the first tubular member either passes along the wall thereof away from the aperture and then to the outlet or possibly down the interior of the tube but away from the aperture, so that in both cases water does not enter the aperture but reaches the drain.

In preferred embodiments of the invention, the ledge surrounds the aperture.

Most preferably, a ledge surrounding the aperture is formed from an end of the second tubular member that projects into the first tubular member and the projecting end provides the ledge. In this embodiment it is preferred that both the first and second tubular members are of circular section and that the ledge is of constant width. It is further preferred that the end of the second tubular member that projects into the first tubular member has an upper arcuate cut-out and the ledge bounds this upper arcuate cut-out. Preferably also the end of the second tubular member that projects into the first tubular member additionally has a lower arcuate cut-out opposed to the upper cut-out and the ledge also bounds this lower arcuate cut-out. The ledge may additionally comprise vertical straight sections disposed on either side of the or each arcuate cut-out. Water draining down the inner wall of the first tubular member may encounter the upper arcuate ledge portion and run therealong to the vertical straight sections, down which the water may then run away from the aperture.

Preferably the first tubular member has a closed lower end that slopes downwardly towards the water outlet.

The water trap unit preferably comprises a third tubular member which is axially offset relative to the first tubular member and extends generally axially parallel thereto, the first and third tubular members being connected by the second tubular member. The third tubular member is closed as its upper end and is mounted at its lower end on the upper outlet end of the exhaust pipe. In this way, the water trap is a "single unit" for convenient mounting on the exhaust pipe.

In particularly preferred embodiments of the invention, the exhaust gas outlet arrangement additionally comprises an air diffuser assembly mounted at the upper end of the first tubular member. The air diffuser assembly is such as to serve a dual role.

One such role is to allow air to be entrained into the hot exhaust gas and effect a degree of cooling thereof. The other role is to act as a primary water separator so that a portion of any water that has entered the air diffuser assembly is drained therefrom and that portion does not pass to the water trap unit. Preferably the air diffuser assembly comprises a lower body portion and an upper exhaust outlet portion. In this arrangement, the body portion of the diffuser has at least one aperture through which air is entrained by the exhaust gas said cooling. The at least one aperture is additionally adapted to drain water from within the lower body portion to externally of the first tubular member.

Use of an air diffuser assembly in the exhaust gas outlet arrangement can provide for removal of about 90% of the water that has entered the outlet of the diffuser assembly before the water reaches the water trap.

According to a second aspect of the present invention there is provided a water trap unit for inhibiting passage of water from external of a vehicle into an exhaust pipe whilst providing passage of exhaust gas through the unit, said water trap unit comprising an outlet tubular member and an inlet tubular member axially off-set from the outlet tubular member, each of said outlet and inlet tubular members having an aperture in the wall thereof, and a bridging tubular member extending transversely between the apertures of said outlet and inlet tubular members to provide communication between the interiors thereof, said outlet tubular member having an exhaust outlet end and a water outlet end, and the inlet tubular member having a closed end and being mountable at its other open end on an upper end of a vertically extending exhaust pipe, wherein within the outlet tubular member said aperture is shielded by a ledge to inhibit passage of water into said bridging tubular member and wherein the outlet tubular member has a water outlet located so as to be below the level of the ledge when the arrangement is mounted to a vertically extending exhaust pipe.

A third aspect of the invention provides an exhaust gas outlet arrangement comprising a water trap unit as defined for the second aspect of the invention and an air diffuser assembly, said air diffuser assembly being mounted at the exhaust outlet end of the outlet tubular member of the water trap unit, said air diffuser assembly having a body portion and an exhaust outlet portion, said body portion of the diffuser having at least one aperture through which air is entrained by the exhaust gas to effect a cooling effect on said gas, said at least one aperture of the body portion being adapted to drain water from within the body portion to externally of the outlet tubular member of the water trap unit.

Features of the first aspect of the invention as described above are applicable mutatis mutar,dis to the second and third aspects of the invention.

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 illustrates one embodiment of exhaust gas outlet arrangement fitted on a verticaly extending exhaust pipe of a truck; Fig. 2 is a cut-away view of part of a water trap unit incorporated in the exhaust gas outlet arrangement shown in Fig. 1; and Fig. 3 is a detail of a tubular member in the water trap unit shown in Fig. 2.

The exhaust gas outlet arrangement 1 shown in Fig. 1 is intended for location on the upper end of a vertical exhaust pipe 2 of a truck complying with the Euro 6 standard, but could equally well be fitted to the exhaust pipe of a truck complying with the Euro 5 or other standard. With regard to the Euro standard, the exhaust system of the truck will include (upstream of the portion of the exhaust pipe 2 shown in Fig. 2) inter a/ia a Diesel Particulate Filter (DPF), a Selective Catalyst Reduction (SCR) unit, and a NO, sensor, all of which must be protected from contact with liquid waste.

The exhaust gas outlet arrangement 1 is fitted onto upper end of exhaust pipe 2 and serves the combined roles of (a) cooling the hot exhaust gas from the pipe 2, (b) discharging the exhaust gas to atmosphere via a directional outlet 16 (see below), and preventing water that may enter the outlet 16 (e.g. as rain, traffic-generated water spray or vehicle wash water) for entering the exhaust pipe 2 and passing to the DPF, SCR unit or NO, sensor.

In more detail, the exhaust gas outlet arrangement 1 comprises a water trap unit 3 located on the outlet end of the exhaust pipe 2 and an air diffuser assembly 4 located on the water trap unit 3. More specifically, water trap unit 3 comprises first and second, axially parallel vertical tubes 5 and 6 respectively which are in communication with each other via upper and lower horizontal tubes 7 and 8 respectively. All of tubes 5-8 are of circular section. Lower end of first tube 5 is secured on the upper end of exhaust pipe 2 whereas the upper end of tube 5 is blanked, as depicted by reference numeral 9 in Fig. 1. The lower end of tube 6 is blanked as indicated by reference numeral 10 in Fig. 2 and slopes downwardly to an aperture 11 (see particularly Fig. 2) which is provided at one side of the lower end of tube 6 and which serves as a water outlet (as described more fully below).

As detailed above, the vertical tubes 5 and 6 are in communication with each other via the horizontal tubes 7 and B which locate through, and are a close fit in, respective apertures in the walls of tubes 5 and 6. Reference is now made to Figs. 2 and 3 which provide further detail as to the manner in which the ends of tubes 7 and 8 are located relative to the vertical tubes S and 6.

As shown in Fig. 2, the horizontal tubes 7 and 8 project a short distance into the tube 6 and provide respective ledge portions 12 and 13 therein which are relatively narrow to prevent excessive back pressure and flow noise. The formation of narrow ledge 12 from the pipe 7 is illustrated in Fig. 3 and is achieved by cutting (or otherwise forming) that end of pipe 7 which locates within tube 6 in upper and lower arcuate sections 12a connected at their ends by straight side sections 12b. The radii of arcuate sections 12a and the dimensioning of the side sections 12b are such that the ledge 12 is of constant width.

At its connection with the vertical tube 5, the end of horizontal tube 7 is cut (or otherwise formed) to match the inner surface of tube 6 (see right hand end of Fig. 3) and does not project therein.

Horizontal tube B is formed, and locates at its ends in the tubes 5 and 6, n exactly the same way described above for the upper horizontal tube 7.

Air diffuser assembly 4 comprises lower and upper, generally cylindrical body component 14 and 15 respectively that are coaxial with each other, the latter being associated at its upper end with directional exhaust outlet 16. It will be appreciated that exhaust gas from the exhaust pipe 2 passes through the outlet 16 via the tube 5, one or other of the tubes 7 and 8, the tube 6, and body portions 14 and 15 of the air diffuser assembly 4.

Upper cylindrical body portion 15 of air diffuser assembly 4 is, over the majority of its length, of greater diameter than the lower cylindrical body portion 14. Upper body portion 15 does however have, at its lower end, a frustoconical section 15a that tapers downwardly to meet the outer surface of cylindrical body portion 14. Formed in the frustoconical portion iSa are four inverted, generally U-shaped cut-outs 17, the function of which will be described below.

As shown, a bracket 18 is provided to fix the exhaust gas outlet arrangement 1 in a suitable position on a truck.

Operation of the exhaust gas outlet arrangement 1 will now be described.

Firstly, it should be noted that one function of the air diffuser assembly 4 is to entrain air into the exhaust gas. In this respect, passage of exhaust gas upwardly through the upper body portion 15 of the air diffuser assembly 4 causes air to be drawn through the cut-out 17 to mix with the gas and effect cooling thereof.

Consider now that water has entered the exhaust gas outlet 16, e.g. due to rain, traffic-generated spray or a wash installation through which the vehicle is passing.

The water (however introduced) passes into the exhaust outlet 16 of the air diffuser assembly 4 and then into the upper cylindrical body portion 15. Within the upper body portion 15, most of the water will run down the interior walls thereof and will be drained via the cut-outs 17 in the frustoconical portion isa. This drained water will then run harmlessly away, e.g. down the outside of pipe 6. In this way, the air diffuser assembly functions as a "primary separator" of the water and as such may drain away about 90% of the water introduced into the exhaust outlet 16. Remaining water then passes into the vertical tube 6. Any water than runs down the inner wall of the tube 6 will either come into contact with the ledges 12 and 13 or will by-pass those ledges and travel to the bottom of tube 6 to be drained through the water outlet 11. Any water that runs down the interior wall of tube 6 into contact with the ledges 12 or 13 is guided around these ledges (possibly falling off the vertical side sections) and is prevented from entering the horizontal tubes 7 and 8. Therefore, water does not enter the vertical tube nor the exhaust pipe 2. Therefore, the DPT, SCR unit and the NO remain protected from water.

It should be appreciated that a number of modifications may be made to the exhaust gas outlet arrangement 1 illustrated in, and described with reference to, Figs. 1-3 of the drawings. Thus, for example, only a single one of the horizontal pipes 7 and 8 might be provided. Alternatively, or additionally, the air diffuser assembly 4, particularly if it is envisaged that any water entering the tube 6 would only ever be minimal.

Claims

CLAIMS1. A vehicle having an exhaust pipe with a vertically extending upper section at the upper end of which is the outlet of the exhaust pipe, said exhaust pipe being fitted at its upper outlet end with an exhaust gas arrangement which inhibits passage of water from external of the vehicle into the exhaust pipe whilst providing passage of exhaust gas to the atmosphere through the arrangement, wherein said outlet arrangement includes a water trap unit comprised of a vertically extending first tubular member axially off-set from the upper section of the exhaust pipe, said first tubular member having an aperture in the wall thereof above the lower end of said tubular member, and a second tubular member extending transversely to said first tubular member from said aperture thereof to provide communication between the interiors of said first tubular member and the upper section of the exhaust pipe wherein wthin the first tubular member said aperture is shielded by a ledge to inhibit passage of water into said second tubular member and wherein the first tubular member has a water outlet below the level of the ledge.
2. A vehicle as claimed in claim 1 wherein said ledge surrounds the aperture.
3. A vehicle as claimed in claim 2 wherein an end of said second tubular member projects into the first tubular member and said projecting end provides the ledge.
4. A vehicle as claimed in claim 3 wherein the first and second tubular members are of circular section and the ledge is of constant width.
5. A vehicle as claimed in claim 4 wherein the end of the second tubular member has an upper arcuate cut-out and the ledge bounds said upper arcuate cut-out.
6. A vehicle as claimed in claim 5 wherein the end of the second tubular member has a lower arcuate cut-out opposed to said upper cut-out and the ledge bounds said lower arcuate cut-out.
7. A vehicle as claimed in claim 5 or 6 wherein the ledge comprises vertical straight sections disposed on either side of the arcuate cut-out(s).
8. A vehicle as claimed in any one of claims 1 to 7 wherein the first tubular member has a closed lower end that slopes downwardly towards the water outlet.
9. A vehicle as claimed in any one of claims 1 to 8 wherein the water trap unit comprises a third tubular member axially offset relative to the first tubular member and connected thereto by the second tubular member, said third tubular member having a closed upper end and being mounted at its lower end on the upper end of the exhaust pipe.
10. A vehicle as claimed in any one of claims 1 to 9 wherein the water trap unit comprises two of said second tubular members.
11. A vehicle as claimed in any one of claims 1 to 10 wherein said exhaust gas outlet arrangement additionally comprises an air diffuser assembly mounted at the upper end of the first tubular member, said air diffuser assembly having a lower body portion and an upper exhaust outlet portion, said body portion of the diffuser having at least one aperture through which air is entrained by the exhaust gas to effect a cooling effect on said gas, said at least one aperture of the lower body portion being adapted to drain water from within the lower body portion to externally of the first tubular member.
12. A vehicle substantially as hereinbefore described with reference to Figures 1-3.
13. A water trap unit for inhibiting passage of water from external of a vehicle into an exhaust pipe whilst providing passage of exhaust gas through the unit, said water trap unit comprising an outlet tubular member and an inlet tubular member axially off-set from the outlet tubular member, each of said outlet and inlet tubular members having an aperture in the wall thereof, and a bridging tubular member extending transversely between the apertures of said outlet and inlet tubular members to provide communication between the interiors thereof, said outlet tubular member having an exhaust outlet end and a water outlet end, and the inlet tubular member having a closed end and being mountable at its other open end on an upper end of a vertically extending exhaust pipe, wherein within the outlet tubular member said aperture is shielded by a ledge to inhibit passage of water into said bridging tubular member and wherein the outlet tubular member has a water outlet located so as to be below the level of the ledge when the arrangement is mounted to a vertically extending exhaust pipe.
14. A water trap unit as claimed in claim 13 wherein said ledge surrounds the aperture.
15. A water trap unit as claimed in claim 14 wherein an end of said bridging tubular member projects into the outlet tubular member and said projecting end provides the ledge.
16. A water trap unit as claimed in claim 15 wherein the outlet and bridging tubular members are of circular section and the ledge is of constant width.
17. A water trap unit as claimed in claim 16 wherein the end of the bridging tubular member has an arcuate cut-out and the ledge bounds said cut-out.
18. A water trap unit as claimed in claim 17 wherein the end of the second tubular member has two arcuate cut-outs opposed to one another, the ledge bounding said arcuate cut-outs.
19. A water trap unit as claimed in claim 17 or 18 wherein the ledge comprises straight sections disposed on either side of the arcuate cut-out(s), the straight sections extending parallel to the longitudinal axis of the inlet tubular member.
20. A water trap unit as claimed in any one of claims 13 to 19 wherein the closed water outlet end of the outlet tubular member slopes downwardly towards the water outlet when the arrangement is mounted on a verticaUy extending exhaust pipe.
21. A water trap unit as claimed in any one of claims 13 to 20 wherein the water trap unit comprises two of said brdging tubular members.
22. A water trap unit substantially as hereinbefore described with reference to Figures 1-3.
23. An exhaust gas outlet arrangement comprising a water trap unit as claimed in any one of claims 13 to 22 and an air diffuser assembly, said air diffuser assembly being mounted at the exhaust outlet end of the outlet tubular member of the water trap unit, said air diffuser assembly having a body portion and an exhaust outlet portion, said body portion of the diffuser having at least one aperture through which air is entrained by the exhaust gas to effect a cooling effect on said gas, said at least one aperture of the body portion being adapted to drain water from within the body portion to externally of the outlet tubular member of the water trap unit.
24. An exhaust gas outlet arrangement substantially as hereinbefore described with reference to Figures 1-3.