Patent Application
20120279606
In the past years, government regulations, including those promulgated by the Environmental Protection Agency (EPA), have required that emission levels of motor vehicles be reduced over time. The EPA has implemented these requirements by setting regulations which requires emission reductions by any company which manufactures motor vehicles, engines or emission systems. Recently, the regulations have become even more stringent and motor vehicle, engine and emission system manufacturers have had to apply new technological components to their vehicles in order to comply with the parameters set forth by the EPA.
The primary goal in reducing emissions is to eliminate as much nitrous oxide in the exhaust stream as possible. This requires that most manufacturers of motor vehicles equip their vehicles with emission systems. The process of eliminating the nitrous oxides is achieved by using “selective catalytic reduction” or SCR systems. In those systems, the nitrous oxides that travel through the exhaust stream come into contact with urea, which is sprayed into the exhaust tube through a nozzle. Upon its injection into the exhaust stream, the urea burns up a majority of the nitrous oxides in the exhaust stream, thus reducing harmful emissions into the atmosphere.
The largest factor in achieving a reduction of nitrous oxides is the temperature of the exhaust gas traveling through the exhaust system. Testing has proven that the higher the temperatures of the exhaust stream, the more nitrous oxides will be eliminated once the urea is injected into the system.
Additionally, insulating the exhaust system has been shown to increase engine performance. This is achieved by hastening the exit of combusted gasses in the exhaust system and allowing the engine to accept a greater volume of cooler intake air. The combusted gasses cool as they leave the chamber and, therefore, lose velocity. Insulating the pipes in the exhaust system keeps the gasses as high a temperature as possible and, therefore, increases the gasses' exit velocity as compared to non-insulated exhaust systems. The increased exit of the combusted gasses reduces back pressure and allows the engine to accept a greater volume of cooler intake air, which results in greater horsepower output.
Because such extreme heat is present within the exhaust system, the ambient air surrounding the exhaust pipes can reach relatively high temperatures as well. Components made of plastic and rubber that surround these exhaust systems can be damaged due to the heat. Therefore, manufacturers have taken precautions such as externally insulating rigid exhaust pipes with insulated blanket wraps to ensure external components are protected and that exhaust temperatures remain high to reach the intended emissions reduction. However, such insulated blanket wraps are consistently subjected to the weather, sun, environmental elements, road gravel and rocks, damage from maintenance, washing and changing of adjacent components, especially in over-the-road trucks, and therefore can become cracked, worn, damaged, punctured or otherwise degraded. Additionally, such blanket wraps and heat shields increase space requirements and require additional mounting clamps, brackets and fastening hardware.
Accordingly, a need exists for an internally insulated rigid exhaust system having insulating properties for reducing emissions and increasing engine performance. Additionally, a need exists for an insulated exhaust conduit where the insulation material is protected from the elements. Further, a need exists for a method of simply and efficiently manufacturing an internally insulated exhaust conduit.
The present invention involves the provision of an internally insulated rigid conduit for use in an exhaust system. The conduit includes an outer rigid tube, a generally flexible inner portion positioned within the outer tube and an insulation layer disposed between the inner portion and outer tube. The inner portion may be a spirally-wound interlock hose member, a bellows member, a braided, chainmail or mesh member or any combinations thereof. The insulation layer may be formed from a sheet, blanket or sleeve or loose particles, fibers, filaments or pieces or an injectable liquid insulation that will expand, dry and harden.
The conduit may include one or more curves or bends. Due to their flexibility, the inner portion and insulation layer generally conform to any bend or curve formed in the outer rigid tube. In one embodiment, one or more spacers are positioned between the inner portion and outer tube for maintaining a generally uniform annular gap therebetween. The spacers may be welded or otherwise attached to the inner portion. In addition to, or alternative to, the spacers, a wire chainmail member or strips may be added in order to position the inner portion within the outer rube, constrict the insulation around the inner portion and/or facilitate the insertion of the inner portion within the outer tube.
The present invention also involves the provision of a method for manufacturing an internally insulated rigid conduit. In one embodiment of the method, the inner portion is wrapped with insulation to form a wrapped subassembly. The wrapped subassembly is then inserted into the outer tube. The wrapped subassembly may be placed within the outer tube either before or after the outer tube has been bent. One or more sleeving fixtures designed to engage the inner portion may be utilized to pull the wrapped subassembly into the outer tube.
In another embodiment of the method, the inner portion is placed within the outer tube such as to define an annular gap therebetween. The inner portion may be placed within the outer tube either before or after the outer tube has been bent. Insulation is then injected, blown, sprayed, stuffed or otherwise placed into the gap. One or more spacers may be used to maintain a generally uniform annular gap between the inner portion and the outer tube. This aids in creating or maintaining a uniform coverage of the insulation material.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.
In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views:
The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures.
The present invention is directed generally toward an internally insulated rigid exhaust system or conduit 10. As illustrated in
The outer rigid tube 12 includes first and second ends 20 and 22 and is of a generally tubular configuration. The outer tube 12 may be of any suitable length and constructed of pipe or other tubing material having a suitable diameter or other geometrical cross-section. As will be appreciated, the tube 12 can be formed of a generally rigid material including steel, stainless steel, aluminum, carbon fiber, polymer, ferrous and nonferrous materials, other metallic and alloy materials or any other suitable material presently known or hereafter developed. The wall of the outer tube 12 may be solid or may include holes, slits, slots or other apertures defined therethrough.
As demonstrated in the figures, insulation material 14 is positioned between the inner portion 16 or 18 and the outer tube 12. As discussed in further detail below, the insulation material 14 may be in the form of a sheet, blanket or sleeve having first and second ends 24 and 26 or loose particles, fibers, filaments or pieces or an injectable liquid insulation that will expand, dry and harden. The insulation material 14 is constructed of any suitable material effective to resist heat transmission. Additionally, the material 14 may be suitable for suppressing noise transmission. Further, the material 14 can provide a barrier that dampens vibrations and prevents the inner portion 16 or 18 and outer tube 12 from physically contacting one another. As a consequence, the conduit 10 may exhibit reduced heat transmission, improved noise control, diminished vibrations and enhanced structural capabilities.
One material that is satisfactory for the insulation material 14 is commercially available silica or silicone fiber insulation. However, other materials having the necessary characteristics can also be used, including but not limited to fiberglass, mineral wool, macroporous materials, microporous materials and foam materials. In one embodiment, the insulation material 14 can have two components: (1) a woven fiber layer and (2) a fibrous material layer. The woven fiber layer serves to protect the inner portion 16 or 18 against wear and serves to prevent the infiltration of insulation fibers through an interlock member 18 and into the exhaust stream. The insulation material 14 may be comprised of any suitable configuration, including but not limited to (1) only a fibrous material, (2) only a woven material, (3) a fibrous material with a woven material on one side or (4) a fibrous material sandwiched between and having woven materials on both sides, (5) multiple layers of any combinations of the insulating materials, among others described here or known to own of skill in the art.
As will be discussed in greater detail below, the insulation material 14 may comprise a sheet of material wrapped around the inner portion 16 or 18 to form a wrapped subassembly that is then inserted into the outer tube 12. The insulation material 14 may be covered or coated with tape, mesh, plastics, glue and/or lubricating materials. In another embodiment, the insulation may be loose insulation that is blown into a gap formed between the inner portion 16 or 18 and the outer tube 12. In either embodiment, it will be appreciated that the inner portion 16 or 18 is surrounded, either partially or wholly, with an insulation material 14. In yet another embodiment, air or a vacuum takes the place of some or all of the insulation in the conduit 10. In that embodiment, the gap or void space between the inner portion 16 or 18 and the outer tube 12 acts to insulate the conduit 10.
The inner portion may be constructed of a generally flexible member. In one embodiment, the inner portion is a spirally-wound interlock hose member 18, as depicted in
In another embodiment, the inner portion may comprise a bellows member 16, as shown in
In hot exhaust applications, the inner portion 16 or 18 is generally manufactured from a metallic material having a melting point temperature higher than the temperature of the exhaust gas. The inner portion 16 or 18 may be formed of a variety of materials including steel, stainless steel, aluminum, carbon fiber, polymer, ferrous and nonferrous materials, other metallic and alloy materials or any other suitable material presently known or hereafter developed.
The use of a flexible inner portion 16 or 18 inside of a rigid outer tube 12 provides the conduit 10 with an internal flexibility not achievable with a rigid inner portion. As illustrated in
Because the inner portion is flexible, it will generally conform to the bend 54 of the outer tube 12. If the inner portion were not a flexible member (i.e., if it were a rigid member), it would not conform to the bend 54 of the outer rigid tube 12 and the gap between the inner portion and the outer tube 12 would not be of a generally consistent width. Rather, there would be a section where no gap exists at all and the inner portion and outer tube 12 would be touching one another.
As demonstrated by
In the embodiment that comprises loose fiber material 14, spacers 80 may be used to maintain the uniformity of the annular gap between the inner portion 16 or 18 and the outer tube 12, as depicted in
As depicted in
Turning now to the methods for manufacturing the conduit 10, it will be understood that the conduit 10 may be manufactured using more than one method. In one embodiment, the inner portion 16 or 18 is wrapped with an insulation material 14 to form a wrapped subassembly. The insulation material 14 may be in the form of a sheet, blanket or sleeve. The wrapped subassembly comprises the inner portion 16 or 18 and the insulation material 14. In addition, a layer of wire mesh or chainmail, in the form of individual strips, a sheet or a tuber member, may be added around the insulation material 14 in order to constrict the insulation material 14 against the inner portion and/or facilitate with the insertion of the wrapped subassembly by providing a generally smooth surface on the exterior of the wrapped subassembly. The wrapped subassembly is sleeved or inserted into the outer tube 14. The insertion of the wrapped subassembly may occur either prior to or after the outer tube 12 has been bent.
In order to facilitate the insertion of the wrapped subassembly into the outer tube 12, a sleeving fixture 60, as shown in
Once the fixture 60 has engaged the inner portion 16 or 18, the wrapped subassembly may be pulled into the outer tube 12. While the wrapped subassembly may alternatively be pushed into the outer tube 12, the pulling action will generally result in a slight linear expansion of the inner portion 16 or 18 and therefore, a shrinking in diameter, as opposed to expanding in diameter, as the wrapped subassembly is being inserted into the outer tube 12. The threaded pin 74 may be equipped with eyelets 76 that are employed for attaching a cable, chain, rope or other suitable line to the fixture 60 for pulling.
Once the wrapped subassembly is fully inserted into the outer tube 12, the threaded pin 74 is turned in a reverse direction so as to back the tapered insert 70 out from within the fixture 60. In doing so, bands or o-rings 72 contract the sections 64 back into a retracted position. As the lips 66 disengage the corrugations 32 or 38, the fixture 60 may be removed from the inner portion 16 or 18. The bands or o-rings 72 maintain the sections 64 of the fixture 60 in a retained relationship. Further, as demonstrated in
In another embodiment, the insulation material 14 is placed, injected, blown, stuffed, sprayed or otherwise placed into an annular gap defined between the inner portion and the outer tube 12. In this method, the inner portion is inserted into the outer tube 12 without any insulation 14 wrapped therearound. Once the inner portion is placed within the outer tube 12, the insulation 14 may be blown into the gap defined between the inner portion and outer tube 12. Optionally, a temporary cap may be placed on the end of the conduit 10 opposite the insulation insertion point to allow the insulation 14 to build up and completely compress inside of the gap. The insulation blower tube (not shown) is designed to have a circular slot no greater in size than the gap defined between the inner portion and outer tube 12. The insulation may be injected, blown, sprayed or stuffed into the gap either before or after the outer tube 12 has undergone bending.
As an additional step, spacers 80 may be placed between the outer surface of the inner portion and the inner surface of the outer tube 12 in order to maintain a generally uniform gap between the inner portion and outer tube 12. The spacers 80 may be welded or otherwise attached to the outer surface of the inner portion. In addition, a layer of wire mesh or chainmail, in the form of individual strips, a sheet or a tuber member, may be added between the inner portion and outer tube 12 in order to maintain a generally uniform gap therebetween.
Optionally, the assembled conduit 10 (which includes an outer rigid tube 12, insulation 14 and a flexible inner portion 16 or 18) may be bent to a desired angle in a bending process. The advantage of the present invention is that during the bending process the flexible inner portion 16 and 18 and the insulation 14 will conform to the bend(s) that the rigid out tube 12 is experiencing. The bending process may be undertaken using a pipe bender, such as a CNC pipe bender, using a press or using any other suitable bending process. The final product is an internally insulated rigid exhaust piping system which can be bent as a user or customer requires.
Finally, the conduit 10 of the present invention will not involve or require the amount of space needed to externally insulate an exhaust system with a blanket wrap. The conduit 10 can be of any desired length, for example, less than one foot, more than 200 feet or anywhere therebetween. The conduit 10 may also be any desired diameter, for example, less than one inch, more than 24 inches or anywhere therebetween. The exhaust piping system of the present invention may also be suitable for operating in a wide variety of temperature ranges, for example, less than −200° F., more than 2500° F. or anywhere therebetween.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting.
The constructions described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.
This Application claims priority to U.S. Provisional Patent Application Ser. No. 61/481,330 filed May 2, 2011 to Michael Teso entitled “Internally Insulated Exhaust System,” currently pending, the entire disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61481330 | May 2011 | US |
