GB2510888A

GB2510888A - A catalytic converter assembly

Info

Publication number: GB2510888A
Application number: GB1302777.6A
Authority: GB
Inventors: James Donnelly
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2013-02-18
Filing date: 2013-02-18
Publication date: 2014-08-20
Also published as: CN203742729U; GB201302777D0; DE102014202727A1

Abstract

A catalytic converter assembly 20, for an internal combustion engine, comprises a catalytic converter housing 21 which is configured to house a catalytic converter 19, and an outlet housing 22 comprising an outlet 23 of the catalytic converter assembly. The outlet housing is configured such that an end 21b of the catalytic converter housing extends into a chamber 26 defined by the outlet housing. The outlet is set back from the end of the catalytic converter housing such that in use exhaust gases flowing through the outlet housing flow over at least a portion of an outer facing surface 27 of the catalytic converter housing. A spray injector 30 may spray urea into the outlet housing chamber. The catalytic converter assembly may be part of an exhaust system which comprises further exhaust treatment devices (e.g. a further catalytic converter, DPF or SCR system) downstream of the catalytic converter assembly.

Description

A CATALYTIC CONVERTER ASSEMBLY

The present disclosure relates a catalytic converter assembly for an internal combustion engine.

Background

Exhaust systems for automotive internal combustion engines typically comprise a catalytic converter. The catalytic converter comprises a catalyst which reduces harmful emissions from the internal combustion engine by converting such emissions into less harmful substances by way of a catalysed chemical reaction.

Typically, a catalytic converter must reach a particular temperature before it can operate effectively. This temperature is referred to as the "light-off' temperature. As a result, catalytic converters may be close-coupled to an exhaust of the internal combustion engine to reduce the time to light-off and reduce harmfiul emissions in the interim.

However, in automobile applications there is typically little available space in the vicinity of the engine and compromises on the proximity of the catalytic converter to the exhaust of the engine may have to be made.

In addition, the arrangement of an exhaust system comprising the catalytic converter is typically bespoke to the particular application, for example a particular automobile model. This is undesirable in respect of the extra design required for such systems and the resulting increase in component inventory.

The present disclosure seeks to address these issues.

Statements of Invention

According to a first aspect of the present invention there is provided a catalytic converter assembly for an internal combustion engine, the catalytic converter assembly comprising: a catalytic converter housing, the catalytic converter housing being configured to house a catalytic converter; and an outlet housing comprising an outlet of the catalytic converter assembly, the outlet housing being configured such that an end of the catalytic converter housing extends into a chamber defined by the outlet housing, wherein the outlet is at least partially set back from thc end of the catalytic converter housing such that in use exhaust gases flowing through the outlet housing flow over at least a portion of an outer facing surface of the catalytic converter housing.

The catalytic converter assembly may thrther comprise a spray injector. The spray injector may he configured to inject a spray into the outlet housing chamber. The spray injector may be configured to inject urea i.nto the outlet housing chamber.

The catalytic converter housing and outlet housing may define an annulus in a region where the catalytic converter housing and outlet housing may overlap. For example, an inner wall of the outlet housing and an outer wall of the catalytic converter housing may 1 5 define the annulus. The catalytic converter housing and outlet housing may be substantially cylindrical, although they may be any other shape. A cross-sectional area of the annulus maybe substantially equal to a cross-sectional area of the catalytic converter.

The outlet may be provided in the region where the catalytic converter housing and outlet housing overlap, e.g. such that the outlet may be in fluidic communication with the annulus. The outlet may be provided in an outer wall of the outlet housing.

The outlet housing may guide exhaust gas flow from the catalytic converter through the outlet. The outlet housing may comprise an end wall. The end wall may comprise an opening for receiving the end of the catalytic converter housing extending into the outlet housing chamber. The end wall may be disposed adjacent to the annulus, The end wall may be set back from the end of die catalytic converter housing.

The catalytic converter assembly may be configured to be close coupled to the internal combustion engine. The catalytic converter assembly may be close coupled to an outlet associated with the engine, for example, an engine exhaust manifold or a turbocharger outlet.

An exhaust system for an internal combustion engine may comprise the aforementioned catalytic converter assembly.

The exhaust system may further comprise an exhaust treatment assembly. The cxhaust treatment assembly may be configured for placement downstream of the catalytic converter assembly.

The exhaust system may further comprise a link pipc. The link pipe may be configured 1 0 for placement between the catalytic convcrtcr assembly outlet and the exhaust treatment assembly.

The exhaust treatment assembly may comprise a further catalytic converter. The exhaust treatment assembly may comprise a diesel particulate filter. The exhaust 1 5 treatment assembly may comprise a selective catalytic reduction system. The exhaust treatment assembly may comprise a combined selective catalytic reduction system and diesel particulate filter. The exhaust treatment assembly may comprise any combination of the aforementioned components.

The exhaust treatment assembly may be adjustable in size, e.g. length. The exhaust treatment system may be customizable for a particular application.

The exhaust system may further comprise a urea dosing unit. The urea dosing unit may be coupled to the outlet housing for dispensing urea into the outlet housing chamber.

The exhaust system may be modular. One or more components oithe exhaust system may be common across a range of vehicle platforms.

Brief Description of the Drawings

For a better understanding of the present disclosure, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows an exhaust system according to an example of the present disclosure; Figures 2a and 2b show sectional side views of a catalytic converter assembly according to an example of the present disclosure with or without a spray injector respectively; and Figure 3 shows a sectional end view of a catalytic converter assembly according to an

example of the present disclosure.

Detailed Description

With reference to Figure 1 the present disclosure relates to an exhaust system 10 for an automobile, in particular for an internal combustion engine of an automobile. in a particular example, the present disclosure may apply to a diesel engine, although it may equally apply to a petrol engine or any other type of engine. The exhaust system 10 comprises a catalytic converter assembly 20. As depicted, the exhaust system I 0 may further comprise an exhaust treatment assembly 40, which may be placed downstream of the catalytic converter assembly 20.

A link pipe 50 may be provided between the catalytic converter assembly 20 and the exhaust treatment assembly 40. It will be appreciated that exhaust gases from the internal combustion engine (e.g. from the exhaust manifold or turbocharger, neither of which are shown) may flow into the catalytic converter assembly 20, via an inlet 24, and then into the exhaust treatment assembly 40 via the link pipe 50. The exhaust from the exhaust treatment assembly 40 may be emitted from an exhaust treatment assembly outlet 42. The exhaust may then be emitted, e.g. from the automobile, via flirther ducting (not shown).

The catalytic converter assembly 20 may comprise a catalytic converter (not shown), which is configured to convert engine emissions into less harmful substances by way of a eatalysed chemical reaction. For example, the catalytic converter may convert carbon monoxide to carbon dioxide; unburnt hydrocarbons to carbon dioxide and water; nitrogen oxides to nitrogen; andior any combination of these reactions. Flowever, in a particular arrangement, the catalytic converter may convert carbon monoxide to carbon dioxide andior unhurnt hydrocarbons to carbon dioxidc and water. A catalyst of the catalytic converter maybe provided on a honeycomb structure, which may be ceramic or metallic. The catalyst may comprise platinum, palladium, rhodium, cerium, iron, manganese, nickel, copper, any other suitable material or combination thereof.

The exhaust treatment assembly 40 may comprise a further catalytic converter.

Features described with respect to the catalytic converter may apply equally to the fUrther catalytic converter. In particular, the exhaust treatment assembly 40 may comprise a catalytic converter for converting nitrogen oxides to nitrogen or nitrogen and water. For example, the exhaust treatment assembly may comprise a selective catalytic reduction system.

1 5 In addition or alternatively to the further catalytic converter, the exhaust treatment assembly 40 may comprise a diesel particulate filter. In a particular example, the exhaust treatment assembly 40 may comprise a combined selective catalytic reduction system and diesel particulate filter, for example in which the selective catalytic reduction system may be provided on a surface of the diesel particulate filter.

The exhaust system 10 may be modular. For example, the catalytic converter assembly andlor exhaust treatment assembly 40 may be common across a range of vehicle platforms. In this way, the design and validation burden may be reduced and the stock inventory minimised. Furthermore, by dividing the functions of the catalytic converter and the exhaust treatment assembly, a more adaptable exhaust system may be provided.

However, the exhaust treatment assembly 40 may he adjustable in size, e.g. length. For example, a range of exhaust treatment assemblies 40 maybe provided, which may vary in length. The exhaust treatment assemblies may vary in length only. In this way, the exhaust treatment system may be customizable for a particular application, e.g. a particular automobile model. Designing and validating a longer or shorter exhaust treatment assembly may be readily achieved and it may be straightforward to supply and stock exhaust treatment assemblies varying in length.

The link pipe 50 may be customised for a particular application, e.g. a particular automobile model. Designing a link pipe for a particular application may be less onerous than designing particular catalytic converters for each automobile model. It may also be easier to supply and stock a range of link pipes as opposed to particular catalytic converters for each automobile model.

With reference to Figures 2 and 3, the catalytic converter assembly 20 comprises: a catalytic converter housing 21 and an outlet housing 22 comprising an outlet 23 of the 1 0 catalytic converter assembly. As mentioned above, the catalytic converter assembly 20 may comprise a catalytic converter and the catalytic converter housing 21 may bc configured to house the catalytic converter 19. The outlet housing 22 may guide exhaust gas flow from the catalytic converter 19 through the outlet 23.

The catalytic converter assembly 20 may be configured to be close coupled to the internal combustion engine. The catalytic converter assembly 20 may be close coupled to an outlet associated with the engine, for example, an engine exhaust manifold or a turbocharger outlet.

The catalytic converter assembly 20 may comprise the inlet 24 which may be provided in an inlet cone 25, The inlet cone 25 may be coupled to an inlet end 21a of the catalytic converter housing 21. The inlet cone 25 may increase the cross-sectional area of the flow from the inlet 24 to the inlet end 21 a of the catalytic converter housing.

As depicted, an outlet end 2lb of the catalytic converter housing 21 may extend into a chamber 26 defined by the outlet housing 22. Accordingly, the outlet housing 22 may be greater than the catalytic converter housing 21 in size, e.g. diameter, at least where they overlap. The outlet 23 may be at least partially set back from the outlet end 21b of the catalytic converter housing 21. For example, a portion of an opening defining the outlet 23 may be set back from the outlet end 21b of the catalytic converter housing 21.

Alternatively, all of the opening defining the outlet 23 may be set back from the outlet end 21 b of the catalytic converter housing 21.

Accordingly, it will be appreciated that in use exhaust gases flowing through the outlet housing 22 may flow through an annulus 31 defined by the catalytic converter housing 2 I and outlet housing 22 (as indicated by the arrows in Figures 2a and 2b). The exhaust gases may flow over at least a portion of an outer facing surface 27 of the catalytic converter housing 21.

The outlet housing 22 may comprise a first end wall 28a. The first end wall 28a may be substantially perpendicular to a longitudinal axis of the catalytic converter housing 21, or, as depicted, the first end wall 28a may be angled with respect to the longitudinal axis of the catalytic converter housing 21. The first end wall 28a may comprise an opening 29 for receiving the outlet end 21b of the catalytic converter housing 21 extending into the outlet housing chamber 26. In other words, the catalytic converter housing 21 may extend through the opening 29 in the first end wall 28a. The end wall 28a may be set back from the outlet end 21 b of the catalytic converter housing 21.

The outlet housing 22 may comprise a second end wall 28b. The second end wall 28b may extend across an end of the outlet housing 22. The second end wall 28b maybe radiused where it joins the remainder of the outlet housing 22. The second end wall 28b, e.g. the radiused edge, may guide flow from the catalytic converter toward the annulus 31 defined by the catalytic converter housing 21 and outlet housing 22.

A lining 18 may be provided between the catalytic converter 19 and the catalytic converter housing 21. The lining 18 may be set back from the one or both of the inlet and outlet ends 21 a, 2 lb of the catalytic converter housing 21.

Referring to Figure 2b, the catalytic converter assembly 20 may further comprise a spray injector 30, which is depicted in schematic form. The spray injector 30 may be configured to inject a spray, e.g. a spray of liquid droplets, into the outlet housing chamber 26. In a particular example, the spray injector 30 may be configured to inject urea into the outlet housing chamber. The injection of urea may be used in a selective catalytic reduction reaction in the exhaust treatment assembly 40. Accordingly, it will be appreciated that the exhaust system 1 0 may ftirther comprise a urea dosing unit (not shown). The urea dosing unit may be coupled to the outlet housing 22 for dispensing urea into the outlet housing chamber. Injecting a spray into the outlet housing chamber 26 may result in greater mixing of the spray with the exhaust gases, e.g. by virtue of the turning of the flow and/or any turbulence in this region.

As depicted in Figure 3, the catalytic converter housing 21 and outlet housing 22 may define the annulus 3 1 in a region where the catalytic converter housing and outlet housing may overlap. For example, an inner wall 32 of the outlet housing 22 and the outer facing surface 27 of the catalytic converter housing 21 may define the annulus 31.

As shown, the catalytic converter housing 21 and outlet housing 22 may be substantially 1 0 cylindrical, at least in the region of the annulus 31, although they may be any other shape. The catalytic converter housing 21 and outlet housing 22 maybe substantially concentric, at least in the region of the arniulus 3 L The outlet 23 may be provided in the region where the catalytic converter housing 21 and outlet housing overlap 22. As a result, the outlet 23 may be in fluidie communication with the annulus 31. The outlet 23 maybe provided in the outer wall 33 of the outlet housing 22. The outlet 23 may connect to the link pipe 50 of the exhaust system tO.

A cross-sectional area 34 of the annulus 31 may be substantially equal to a cross-sectional area 35 of the catalytic converter. In this way, the flow of exhaust gases though the outlet housing may not be unduly impeded by flowing into the annulus 31 and a pressure drop across the catalytic converter assembly 20 may be minimiscd.

The outlet housing of the present disclosure may enable a shorter catalytic converter assembly 20 without necessarily affecting a pressure drop across the catafytic converter assembly. This may be achieved thanks to the cross-sectional area of the annulus and/or the increased residence time of the exhaust flow in the outlet housing.

It will be appreciated that a shorter catalytic converter assembly may be used in a wider range of applications, in particular, applications where space close to the engine is limited. As a result, the same catalytic converter assembly 20 may be used in a range of applications, e.g. a range of automobile models. In this way, the design and validation burden may be reduced and the stock inventory minimised.

Furthermore, the direct flow of the exhaust gases from the engine into the catalytic converter may ensure that the light-off temperature of the catalytic converter is reached quickly. The flow of the exhaust gases over the outer facing surface of the catalytic converter housing may also recover heat from the exhaust gases and assist in warming up the catalytic converter more quickly. In other words, heat from the exhaust gases may be transferred to the catalytic converter through the catalytic converter housing 1 0 where it overlaps with the outlet housing.

Claims

Claims 1. A catalytic converter assembly for an internal combustion engine, the catalytic converter assembly comprising: a catalytic converter housing, the catalytic converter housing being configured to house a cata]ytic convertcr; and an outlet housing comprising an outlet of the catalytic converter assembly, the outlet housing being configured such that an end of the catalytic convertcr housing extends into a chamber defined by the outlet housing, wherein thc outlet is at least partially set back from the end of the catalytic converter housing such that in usc exhaust gases flowing through the outlet housing flow over at least a portion of an outer facing surface of the catalytic converter housing.
2. The catalytic converter assembly of claim I, wherein the catalytic converter assembly further comprises a spray injector, the spray injector being configured to inject a spray into the outlet housing chamber.
3. The catalytic converter assembly of claim 2, wherein the spray injector is configured to inject urea into the outlet housing chamber.
4, The catalytic converter assembly of any of the preceding claims, wherein the catalytic converter housing and outlet housing define an annulus in a region where thc catalytic converter housing and outlet housing overlap.
5. The catalytic converter assembly of claim 4. wherein a cross-sectional area of the annulus is substantially equal to a cross-sectional area of the catalytic converter.
6. The catalytic converter assembly of claim 4 or 5, wherein the outlet is provided in the region where the catalytic converter housing and outlet housing overlap such that the outlet is in fluidic communication with the annulus.
7. The catalytic converter assembly of any of the preceding claims, wherein the outlet is provided in an outer wall of the outlet housing.
8. The catalytic converter assembly of any of the preceding claims, wherein the outlet housing comprises an end wall, the end wall comprising an opening for receiving the end of the catalytic converter housing extending into the outlet housing chamber.
9. The catalytic converter assembly of any of the preceding claims, wherein the catalytic converter assembly is configured to be close coupled to the internal combustion engine.
10. An exhaust system for an internal combustion engine, the exhaust system comprising the catalytic converter assembly of any of the preceding claims.
11. The exhaust system of claim 10, wherein the exhaust system further comprises an exhaust treatment assembly, the exhaust treatment assembly being configured for placement downstream of the catalytic converter assembly.
12. The exhaust system of claim II, wherein the exhaust system further comprises a link pipe, the link pipe being configured for placement between the catalytic converter assembly outlet and the exhaust treatment assembly.
13. The exhaust system of claim 11 or 12, wherein the exhaust treatment assembly comprises a further catalytic converter.
14. The exhaust system of any of claims 11 to 13, wherein the exhaust treatment assembly comprises a diesel particulate filter.
1 5. The exhaust system of any of claims Ii to 14, wherein the exhaust treatment assembly comprises a selective catalytic reduction system.
16. The exhaust system of any of claims 11 to 15, wherein the exhaust treatment assembly comprises a combined selective catalytic reduction system and diesel particulate filter.
17. The cxhaust system of any of claims 11 to 16, wherein the exhaust treatment assembly is adjustable in size.
18. The exhaust system of any of claims 10 to 17, wherein the exhaust system further comprises a urea dosing unit, the urea dosing unit being coupled to the outlet housing of the catalytic converter assembly for dispensing urea into the outlet housing chamber.
19. The exhaust system of any of claims 11 to 18, wherein the exhaust system is modular with one or more components of the exhaust system being common across a range of vehicle platforms.
20. A catalytic converter assembly or exhaust system as described herein with reference to and as shown in the accompanying drawings.