WO2009012819A1

WO2009012819A1 - Exhaust gas system for commercial vehicles

Info

Publication number: WO2009012819A1
Application number: PCT/EP2007/060976
Authority: WO
Inventors: Andreas Lang; Michael Wolf; Sascha Haverkamp
Original assignee: Heinrich Gillet Gmbh
Priority date: 2007-07-26
Filing date: 2007-10-15
Publication date: 2009-01-29
Also published as: DE202007010435U1

Abstract

The invention relates to an exhaust gas system for commercial vehicles, comprising an inlet pipe (1), a first housing (2) for receiving at least one first functional body (2.1, 2.3), a second housing (3) for receiving at least one second functional body, a crossflow pipe (4) which connects the first housing and the second housing, and an outlet pipe (6), wherein at least one of the housings has an inlet hood (10), an outlet hood (10), a removable housing cover (11) or housing cover section (11.2) which is arranged between the former, and releasable connecting clips (13).

Description

Exhaust system for commercial vehicles

Description:

The invention relates to exhaust systems for commercial vehicles according to the preamble of claim 1.

Exhaust systems for motor vehicles with internal combustion engine, especially for commercial vehicles, must combine the three areas of sound reduction, exhaust aftertreatment and support for additional elements of the motor vehicle user in itself. Furthermore, the exhaust systems should be as compact as possible and also variable for adaptation to a wide variety of motor vehicle types. The currently commercial exhaust systems for commercial vehicles meet these conditions only partially and only to a small extent. There is therefore still a need for improved solutions.

The present invention is therefore an object of the invention to provide an exhaust system of the type mentioned, which is compact and variable, which allows a realization of a modern exhaust aftertreatment system in whole or in part, allows a reduction of the exhaust noise to the values prescribed by law and that with minimal pressure loss.

This object is achieved by an exhaust system with the features of claim 1. Thanks to the modular construction of housings made of removable housing shell or housing shell section, inlet hood and outlet hood, thanks to the use of inlet, outlet and overflow pipes and thanks to the detachable connection of the housing shell with the inlet hood and the outlet hood using connecting clamps, compared to the known exhaust systems in Form of box structures, a cost-effective, flexible and maintenance-friendly exhaust system can be provided. In particular, the division of the housing into the housing shell and the inlet and outlet hood allows easy separability for cleaning purposes, for example, if a diesel particulate filter (DPF short) is arranged as a functional body in the housing shell, which can be easily removed or replaced after loosening the connection clamps. Further functional bodies are, for example, a diesel oxidation catalyst (short DOC) or a reduction catalyst (abbreviated to SCR catalyst for "selective catalytic reduction").

The removable housing shell or housing shell section particularly preferably has a round cross-section. The use of cylindrical or tubular components reduces the cost of the exhaust system with the greatest possible flexibility.

Preferably, the inlet pipe, the overflow pipe and / or the output pipe are detachably connected by means of clamp or by means of flange with the housing, whereby the exhaust system can be flexibly adapted to all possible situations of use.

Advantageously, the inlet and outlet hoods are thermally and as a result also acoustically insulated. In this way, the noise level in the exhaust gas is lowered while reducing the heating of the environment. In addition, the operation of the catalysts and required for the regeneration of the particulate filter temperature reached and maintained faster, which is particularly important in diesel engines because of their relatively low exhaust gas temperature is particularly important.

Advantageously, the overflow pipe is thermally insulated. The reasons and advantages are the same as with the inlet and outlet hoods.

It is understood that for the same reasons, the housing shells should be isolated. This is achieved according to the invention in that bearing mats, in particular thick bearing mats, are used in the housing between the housing jacket and the functional bodies active as catalyst or particle filter.

Preferably, the inlet and outlet hoods are designed aerodynamically in the interior. In particular, the inlet hood of the diesel catalyst using a Anström plate, which distributes the inflowing exhaust gases as evenly as possible over the end face of the following functional body, flow optimized.

Particularly preferably, the inlet hood and / or the outlet hood has a double-walled end-side end floor, between the walls of which insulating material for reducing heat and structure-borne sound radiation is arranged. In this way, a particularly efficient thermal or acoustic insulation is realized.

A particularly simple assembly is obtained when the inlet hood or the outlet hood is formed from two nested steel pots of different sizes, which form a double wall on the bottom side and circumferentially and arranged between which insulating material for reducing heat and structure-borne noise radiation - A -

is. The steel pans with the insulating material between them to reduce heat and structure-borne sound radiation are in other words inserted into one another according to the shoe box principle and preferably connected in the region of their edges by means of spot welding. Due to the non-detachable connection, the steel pots, together with the insulation between them, form an integral and universal component, which can be easily mounted.

Particularly preferably, an injection nozzle for an additive is provided, which opens into the exhaust system in the region of the overflow pipe. Injection nozzles for exhaust systems for introducing chemically reactive additives, in particular hydrocarbon compounds or urea solution, are known. The arrangement in the region of the overflow pipe proves to be particularly favorable in order to achieve a good distribution or atomization of the additive in the exhaust gas before this mixture is fed to an SCR catalyst.

Furthermore, a metallite catalyst for improving the light-off functionality of the diesel oxidation catalyst is preferably arranged in the inlet pipe.

According to one embodiment of the invention, the output tube is covered with a surface resonator. With the help of such a surface resonator difficult acoustic problems can be mastered in special cases.

According to another embodiment of the invention, the output tube is closed at the end and has circumferentially distributed large-area outlet perforations. These serve to quickly mix the exhaust gas temperature after leaving the outlet pipe with ambient air and so meet the temperature requirements after discharge, in particular to to prevent neighboring parts from being scorched or even set on fire.

As mentioned above, the exhaust systems or their holders are also a place where the motor vehicle user attaches additional elements, such as wheel chocks, tool boxes and the like. The brackets of the exhaust system must therefore not only be able to carry their own weight but also the weight of the possible additional elements. It has therefore been found that L-shaped holder as support structures can fulfill this additional function with minimal additional effort.

Finally, it is possible to attach threaded bushes to housings, inlet and outlet hoods, inlet pipe, overflow pipe and / or outlet pipe for the temperature, pressure, oxygen, NOx and / or NH ₃ sensors required for operating the engine and exhaust system.

In particular, the exhaust system for commercial vehicles according to the invention can thus comprise:

- an entrance pipe,

a diesel oxidation catalyst in a housing separable for cleaning,

a particulate filter in a housing separable for cleaning purposes, typically in the same housing behind the DOC,

- an overflow pipe,

- An injector for an additive

- And / or an output tube, wherein

there is a metallite catalyst in the inlet pipe for improving the light-off functionality of the diesel oxidation catalyst,

- The housing further - inlet and outlet hoods,

- A housing shell

- and releasable connection clamps include and

- The nozzle sits in the overflow pipe.

Reference to the drawings, the invention will be explained in more detail in the form of embodiments. They each show purely schematically

1 shows an oblique view of a first exhaust system,

2 is an oblique view of a second exhaust system with holders,

Fig. 3 is an oblique view of a third exhaust system and

4 shows a longitudinal section through the exhaust system of FIG. 1.

Fig. 1 shows purely schematically an oblique view of a first exhaust system. It can be seen an inlet pipe 1, which (not shown) from a diesel engine exhaust gases in a diesel oxidation catalyst in a first housing 2 passes. In the interior of the first housing 2, a diesel particulate filter (short DPF) can be located downstream of the DOC in the flow direction. To improve the light-off functionality, a metallite catalyst is integrated in the inlet pipe 1. For cleaning purposes and to increase the variability, the housing elements of the first housing 2, namely an inlet hood 10, a housing jacket 11 and an outlet hood 10, are releasably connected to one another by means of clamps 13 (not shown in FIG. 1).

The exiting at the end of the diesel oxidation catalyst exhaust gas flows into an overflow pipe 4, at the input of a nozzle 5 is seated Adding additives into the exhaust gas, for example, an aqueous urea solution, which is needed so that the chemical reaction can proceed in a subsequent SCR catalyst. The exhaust-urea mixture swirls still in the overflow 4 and further at the entrance into a second housing 3, in which the SCR catalyst is arranged. The second housing 3 of the SCR catalytic converter consists of a housing jacket 11 with inlet and outlet hoods 10. The diesel particulate filter may also be located inside the second housing 3 behind the SCR unit, if this is more favorable for different reasons, for example the exhaust gas temperature ,

The cleaned and filtered exhaust gas leaves the exhaust system via an output pipe 6. This is closed in this embodiment at the end and has at the periphery large-area outlet perforations (not shown), through which the exhaust gas exits into the atmosphere. In this case, an intimate mixing with ambient air, whereby the exhaust gas temperature is greatly reduced, so there is no risk of fire.

Fig. 2 also shows purely schematically and as an oblique view of a second exhaust system. The two large housings 2, 3 are arranged directly adjacent to one another in adaptation to another installation situation. However, there are again the overflow pipe 4, the inlet pipe 1 and the outlet pipe 6, which, however, is provided with an end pipe 7 with the aid of which the cleaned and filtered exhaust gases are discharged upwards.

It can also be seen stable L-shaped holder 12 whose free legs (not visible) wear the exhaust system and can also accommodate the weight of any additional elements. Finally, it can be seen in Fig. 2 also still the two clamps 13, which hold the various housing parts in operation and sufficiently seal against exiting exhaust gases, however, allow for cleaning purposes, a convenient opening of the housing.

Fig. 3 also shows purely schematically and as an oblique view of a third embodiment. Here is the overflow tube 4 with inserted nozzle 5 below the second housing eleventh

FIG. 4 shows a longitudinal section through the exhaust system of FIG. 1. The inlet tube 1, which enters the inlet hood 10, can be seen. This includes a double-walled end-side end floor 10.2, between the walls of insulation material 10.1, typically (woven) E-glass wool, arranged to reduce heat and structure-borne noise radiation. The end floor is either itself designed as a flow-optimized Anströmblech or there is a separate Anströmblech provided in the inlet hood 10, which provides for a uniform distribution of entering through the inlet pipe 1 exhaust downstream to the end face of the first functional body 2.1, in this case, for example, a DOC , The inlet hood 10 is formed from two nested steel pots of different sizes, which form not only the bottom side but also circumferentially a double wall in the space also insulating material for thermal and acoustic insulation is provided.

The inlet hood 10 is connected downstream with a housing shell 11, which in this embodiment of a first housing shell portion 11.1 for receiving a first functional body 2.1 (DOC) and a second housing shell portion 11.2 for receiving a second Functional body 2.3 (DPF) exists. The housing shell sections are preferably made of a cylindrical steel tube. Both functional body 2.1, 2.3 are supported by means of thick bearing mats 2.2, 2.4 (typically glass fiber mats) in the housing shell 11, wherein the bearing mats are compressed and produce a press fit in the steel tube, which makes an additional mechanical fixation superfluous. The bearing mats 2.2, 2.4 simultaneously act as thermal insulation.

The tube of the first housing shell portion 11.1 is fixedly connected to the inlet hood 10, preferably by a gas-tight circumferential weld. A detachable connection is not necessary at this point because the DOC typically arranged therein does not need to be replaced. The downstream arranged second housing shell portion 11.2 is held in contrast by means of two clamps 13 in its position. A clamp connects the one axial end of the second housing shell portion 11.2 with the free end of the first housing shell portion 11.1 and closes the joint at the same time largely gas-tight. The other clamp connects the other axial end of the second housing shell portion 11.2 with the free end of the downstream outlet hood 10 and creates there a largely gas-tight seal. In this case, a seal that does not exceed a limit value of the gas outlet of 20 L / min at 0.3 bar overpressure in the exhaust system, be considered sufficient. The clamps are a detachable connection that allows easy removal or replacement of this housing part and the functional body therein, in particular the DPF, by the second housing shell portion 11.2 can be removed after opening and axial displacement of the clamps in the radial direction. The exiting from the second functional body 2.3 exhaust gas enters an outlet hood, which coincides in shape and size with the inlet hood 10, which allows a rational production.

From the outlet hood, the exhaust gases pass into the overflow pipe 4, the wall of which is insulated thermally and acoustically with insulating material 4.1.

With the aid of the nozzle 5, an additive, for example an aqueous urea solution or a hydrocarbon, is injected into the exhaust gases in the overflow pipe 4.

The exhaust gases pass from the overflow pipe 4 into a second inlet hood 10, which belongs to the second housing 3, which accommodates a third functional body, typically the SCR catalytic converter. The second housing 3 is constructed identically or at least substantially equal to the first housing 2, so that the same housing components can also be used here, wherein here, for example, no releasable connection must be provided, but all housing sections can be welded together.

From the outlet hood 10 of the second housing 3, the exhaust gases pass into the outlet tube 6, the end of which, however, can no longer be seen in the drawing. LIST OF REFERENCE NUMBERS

1 inlet pipe

2 first housing

2.1 first functional body (DOC)

2.2 storage mat

2.3 second functional body (DPF)

2.4 Storage mat

3 second housing

4 overflow pipe

5 nozzle

6 output pipe

7 tailpipe

10 inlet and outlet hood

10.1 Insulation material

10.2 end floor

11 housing jacket

11.1 first housing shell section

11.2 second housing shell section

12 holders

13 clamp

Claims

Claims:

1. Exhaust system for commercial vehicles, comprising

an inlet pipe (1),

a first housing (2) for receiving at least one first functional body (2.1, 2.3),

a second housing (3) for accommodating at least one second functional body,

- A connecting the first and second housing overflow pipe (4)

- And an output tube (6), wherein at least one of the housing an inlet hood (10), an outlet hood (10), a removable housing shell arranged therebetween (11) or

Housing shell portion (11.2) and releasable connection clamps (13).

2. Exhaust system according to claim 1, characterized in that the inlet tube (1), the overflow tube (4) and / or the output tube (6) is releasably connected by means of clamp or flange with the housing.

3. Exhaust system according to claim 1 or 2, characterized in that the inlet and / or outlet hood (10) is thermally insulated.

4. Exhaust system according to one of claims 1 to 3, characterized in that the inlet and / or outlet hood (10) is designed fluidically efficient.

5. Exhaust system according to one of claims 1 to 4, characterized in that the overflow pipe (4) is thermally insulated.

6. Exhaust system according to one of claims 1 to 5, characterized in that a bearing mat forms a thermal insulation in the housings.

7. Exhaust system according to one of claims 1 to 6, characterized in that in the inlet hood (10), in particular of the diesel catalyst (2), a Anströmblech is.

8. Exhaust system according to one of claims 1 to 7, characterized in that the output tube (6) is covered with a surface resonator.

9. Exhaust system according to one of claims 1 to 7, characterized in that the output tube (6) is closed at the end and distributed on the circumference arranged large-area outlet perforations.

10. Exhaust system according to one of claims 1 to 9, characterized in that the inlet hood (10) and / or the outlet hood (10) has a double-walled end-side end floor, between the walls of insulating material for reducing heat and structure-borne noise radiation is arranged.

11. Exhaust system according to claim 10, characterized in that the inlet hood (10) and / or the outlet hood (10) are formed from two nested steel pots of different sizes, which form a double wall on the bottom side and circumferentially and between which insulation material for the reduction of heat and structure-borne sound radiation is arranged.

12. Exhaust system according to claim 11, characterized in that the steel pots are connected in the region of their edges by means of spot welding.

13. Exhaust system according to one of the preceding claims, characterized in that an injection nozzle (5) is provided for an additive which opens into the exhaust system in the region of the overflow pipe (2).

14. Exhaust system according to one of the preceding claims, characterized in that in the inlet pipe (1) a Metallit catalyst for improving the light-off functionality of the diesel oxidation catalyst (2) is arranged.

15. Exhaust system according to one of the preceding claims, characterized in that the clamps (13) are arranged to seal the housing (2, 3) sufficiently against exiting exhaust gases.

16. Exhaust system according to one of the preceding claims, characterized in that the removable housing shell (11) or the housing shell portion (11.2) has a round cross-section.