limited States Patent Kofinit [451 June 5, 1973 [54] DEVICE FOR THE COMBUSTION OF BURNABLE COMPONENTS OF Primary ExaminerDouglas Hart EXHAUST GASES Attorney-John J. McGlew and Alfred E. Page [75] Inventor: Siegfried Kotink, Lenzhalde, Ger- [57] ABSTRACT man y A device for the combustion of the burnable coml Asslgnee! Ebel'spachel', Esslmger, Germany ponents of exhaust gases includes a conduit or tube [22] Filed: Apr. 20, 1971 for the passage of the exhaust gases and a heat pipe mounted within the conduit preferably at a spaced lol l PP 135,548 cation from the interior walls in order to permit passage of the exhaust gases around the heat pipe and throu h the conduit. The device also includes means [30] Foreign Application Pnomy Data for di ecting an air supply into the exhaust conduit in May [6, 1970 Germany ..P 20 24 034.0 order to aid in the combustion of exhaust gases under certain exhaust gas conditions. The heat pipe com- [52] [1.8. CI ..23/277 C, 60/282, 60/304, prise a tubular zone closed on all sides and evacuated 0 303 0 323 1 5 105 on the interior. A capillary fabric is arranged adjacent 51 Im. Cl ..F01n 3/10 the inside face and the p p is filled with a quantity of [58] Field of Search ..60/282, 304, 323, a volatile liquid, for example Sodium or potassium 60/303; 23/277 C; 165/105 Such a pipe has a property of being capable of transferring heat with about 10 times the conductivity of [56] References Cited copper. The practical construction is such that the temperature gradient over the entire length of the heat UNITED STATES PATENTS tube is substantially 3,662,542 5/1972 Streb ..60/320 9 Claims, 2 Drawing Figures mm 'llllllllllll-f DEVICE FOR THE COMBUSTION OF BURNABLE COMPONENTS OF EXHAUST GASES SUMMARY OF THE INVENTION This invention relates in general to devices for the further combustion of burnable components of exhaust gases and, in particular, to a new and useful device including a conduit or chamber for the passage of exhaust gases having a heat pipe extending along the length thereof arranged in the exhaust gas flow.

Devices for the combustion of burnable components for exhaust gases are particularly applicable for use with internal combustion engines and provide a means for the detoxication of the exhaust gases. Arrangements are known which are located directly behind the exhaust valves of an internal combustion engine and which comprise whirl bodies and heat storage devices which when they are heated into an incandescent state aid in the burning of the harmful parts of the traversing combustion gases. In the known arrangements, this is achieved by adjusting the combustion mixture of the combustion engine to a weak or lean mixture (for example lambda 1.05 to 1.1) and because of this the combustion gases leave the engine with a certain excess of air. The oxygen still contained in the combustion gases burns in these devices with the burnable residual exhaust gases at the location of the incandescent parts of the recombustion devices. These known recombustion devices have the considerable disadvantage that they are very complicated in construction and have a relatively high pressure loss that is, they produce a counterpressure behind the outlet valves of the combustion engine. Thus the use of such devices is limited and in part impossible in combustion engines of low to medium power because of the power loss which results.

In accordance with the present invention, there is provided a device for the optimum execution of the detoxication of the exhaust gases in combustion engines of low power and also in aircraft engines. In accordance with the invention, a heat pipe is arranged within the zone traversed by the exhaust gas or the exhaust gas conduit itself is designed over at least a portion of its length as a heat tube. The heat pipe advantageously comprises a tube of special construction which has a conductivity which is about times the the conductivity of copper so that the temperature gradient over the entire length of the tube is almost equal to 0. By the use of this device, the combustion gases are in contact with the incandescent heat pipe for the reaction combustion over a relatively long distance through their path of travel through the exhaust tube so that a very good residue combustion particularly of the gaseous components of CO and hydrocarbon components is achieved. Accordingly, it is an object of the invention to provide an improved exhaust gas treatment device which includes a conduit for the passage of the exhaust tubes having a heat pipe extending along the length thereof with a conductivity characteristic which maintains the temperature throughout the length of theheat pipe substantially uniform so that the after combustion of the burnable products of the exhaust gases is carried out in the most optimum manner.

A further object of the invention is to provide an exhaust gas combustion device which includes a heat pipe extending along a substantial length of the exhaust gas conduit and which is supported at a spaced location from the walls thereof by supports which add a whirling movement to the exhaust gases around the heat pipe.

A further object of the invention is to provide an exhaust gas treatment device which is simple in design, rugged in construction, and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference should be had to the accompanying drawing and descriptive matter in which there are illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the Drawing:

FIG. 1 is a longitudinal sectional view of a portion of an exhaust conduit having a heat pipe therein and constructed in accordance with the invention;

FIG. 2 is a view similar to FIG. 1 showing another embodiment of the invention.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing in particular, the invention embodied therein in FIG. 1 comprises, an exhaust gas fitting 1 having a plurality of connecting flanges 1a, lb, etc., for conducting away exhaust gases from one or more locations for example, from the separate cylinders of an internal combustion engine. The exhaust gases pass through the various connecting fittings 1a, 1b, 1c, Id, through an exhaust gas tube 3 which has an interior or zone 4 along which the exhaust gases flow.

In accordance with the invention, a heat pipe or tube 5 is mounted on supports or vanes 6 at a spaced location from the interior walls of the pipe 3 and it extends along a considerable length of the pipe. The supports 6 are designed as webs which impart a whirling motion or twist to the exhaust gas flow as indicated at 7 causing the exhaust gas to move around the heat pipe 5 as it passes along the interior of the tube 3 in a direction of the arrow 10.

In some instances it is desirable to provide additional combustion air and this is admitted, for example through an inlet fitting 9, which is located adjacent the exhaust gas inlet 1. A heat insulation 8 is formed around at least a portion of the tube 3 at least in the area of the heat pipe 5. This prevents undesirable heat transfer by radiation.

In the construction of FIG. 1 the heat tube is surrounded on all sides by the exhaust gases which move in a direction of the arrow 10 and it comprises a tubular zone which is closed on all sides and evacuated. A capillary fabric (not shown) is arranged on the inner face of the tube and the tube is filled with a quantity of volatile liquid, for example sodium or potassium. The heat pipe 5 has the property of transferring heat with the conductivity of about 10 power times the conductivity of copper so that the temperature gradient over the entire length of the heat pipe 5 is almost equal to 0. The exhaust gases which flow through the conduit 3 achieve a temperature, in a very short time, for example of from 800 to 1,000, and this temperature is maintained uniformly along the entire length of the pipe 5. By such an arrangement, the burnable components of the exhaust gas will be subjected to uniform combustion conditions and the combustion interreaction will be maintained at an optimum condition over the entire length of the heat pipe 5 because of the uniform temperature involved. The combustion gases therefor remain in contact with the incandescent heat pipe for the reaction combustion over a relatively long distance to the extent of the length of the heat pipe 5 so that a very good residue combustion particularly of the CO and hydrocarbons components is achieved. The system also has the advantage that it is very simple and compact and there is only very little pressure loss in the exhaust gas lines.

By providing in the whirling vanes 6 it is assured that the exhaust gases will be permitted to move in intimate contact with all portions of the surface of the heat pipe 5. Heat insulation 8 ensures that the surrounding area is not unduly heated.

In the embodiment of FIG. 2, there is provided an exhaust gas tube generally designated 3 which includes a portion, for example an interior portion, having a heat pipe formation or a heat pipe liner 5 of double wall construction which is evacuated and includes a wick adjacent the wall thereof and a quantity of a liquid such as sodium or potassium as in the other embodiment. In this construction, the inlet fitting 1 may be connected only to an exhaust line or to a source of air for improving further after-combustion of the exhaust gases. The heat pipe 5 may be of any desired length or a length found suitable for the combustion conditions and the exhaust gas flow which are expected in each given installation.

While a specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A device for the combustion of the burnable components of an exhaust gas comprising an exhaust gas conduit through which the exhaust gases are passed, said conduit having a heat pipe portion therein comprising a tube having an evacuated portion extending along a substantial portion of the length thereof of substantially uniform dimension along its length with a capillary fabric therein and being filled with a quantity of volatile liquid to greatly increase the conductivity thereof and defining a substantially uniform gas flow area with said exhaust conduit which is maintained at a uniform high temperature to cause continued burning of the exhaust gases.

2. A device for the combustion of the burnable components of an exhaust gas comprising an exhaust gas conduit through which the exhaust gases are passed, said conduit having aheat pipe portion therein comprising a tube having an evacuated portion extending along the length thereof with a capillary fabric therein and being filled with a quantity of volatile liquid to greatly increase the conductivity thereof; said heat pipe comprising a separate tube arranged within said exhaust conduit, means for mounting said tube within said conduit at a spaced location from the interior walls thereof.

3. A device for the combustion of the burnable components of an exhaust gas comprising an exhaust gas conduit through which the exhaust gases are passed, said conduit having a heat pipe portion therein comprising a tube having an evacuated portion extending along the length thereof with a capillary fabric therein and being filled with a quantity of volatile liquid to greatly increase the conductivity thereof and means for supplying combustion air into said exhaust conduit.

4. A device for the combustion of the burnable components of an exhaust gas comprising an exhaust gas conduit through which the exhaust gas are passed, said conduit having a heat pipe portion therein comprising a tube having an evacuated portion extending along the length thereof with a capillary fabric therein and being filled with a quantity of volatile liquid to greatly increase the conductivity thereof and a plurality of inlets connected into said exhaust conduit for exhaust gas and at least one inlet for combustion air.

5. A device according to claim 1, wherein said heat pipe comprises a tubular member which is closed at each end and said evacuated portion is formed at the interior and extends from one end to the other.

6. A device according to claim 1, wherein said heat pipe comprises a tube having a double wall construction, the space between the walls being evacuated.

7. A device according to claim 1, wherein said heat pipe comprises said exhaust conduit.

8. A device according to claim 2, wherein said mounting means comprises curved vanes to impart a twisting motion to the exhaust gases passing therethrough.

9. A device according to claim 1, wherein said exhaust conduit is surrounded by an insulation at least in the area of the extension of said heat pipe.