US 3683625 A
A silicon carbide resistance electric heating element is incorporated in the exhaust system of an automobile. The heating of the exhaust gases in this element will, with the addition of extra air, convert carbon monoxide in the exhaust to carbon dioxide. In a preferred form of the invention, an exhaust analyzer is connected to the exhaust system downstream from the heating element and controls an air auxiliary inlet to admit the proper amount of air to eliminate carbon monoxide.
Description (OCR text may contain errors)
United States Patent  3,683,625 McCrink [451 Aug. 15, 1972 SMOG REDUCER 3,088,271 5/1963 Smith ..60/30 72 Inventor: Edward J. McCrink, 7 Lake s 3,261,161 7/1966 Sawyer ..60/3O Northlake, I11. 601 64  Filed: May 25, 1970  Appl. No.: 40,201
 US. Cl ..60/276, 23/277 C, 60/303  Int. Cl ..F0ln 3/14  Field of Search....60/29, 30, 276, 303; 23/277 C  References Cited UNITED STATES PATENTS 2,981,057 4/ 1961 Buttler ..60/29 A 2,038,567 4/1936 Ittner ..60/30 2,771,736 11/1956 McKinley ..60/30 2,837,169 6/1958 Sawyer ..60/30 3,032,969 5/1962 Barnes ..60/30 Primary Examiner-Douglas Hart Attorney-Olson, Trexler, Wolters & Bushnell ABSTRACT admit the proper amount of air to eliminate carbon monoxide.
9 Claim, 4 Drawing Figures ANAL] 25K ADDITIONAL All? g 66 4. [xx/4057- INLET DEV/CE flA/flb/ZER cox/780M503) Ex/Musr SMOG REDUCER BACKGROUND OF THE INVENTION At the present time it is well recognized that automobile exhaust badly pollutes the air. One of the worst pollutants is carbon monoxide which is believed to cause cancer, and which is known to affect adversely the ability of the bloodstream to carry oxygen. It is further known that significant quantities of unburned hydrocarbons pass through an automobile exhaust, and when subjected to sunlight become partially opaque to cause smog. It is recognized that carbon monoxide can readily be oxidized to carbon dioxide, and that the unburned hydrocarbons can be oxidized to eliminate many of the deleterious effects of automotive and the like exhausts. However, systems for accomplishing this end have heretofore either been prohibitively expensive or have adversely affected engine operation.
BRIEF DESCRIPTION OF THE INVENTION AND OBJECTS In view of the foregoing, it is an object of the present invention to provide a simple and inexpensive system for oxidizing components of automotive and the like exhausts.
Specifically, it is an object of the present invention to provide a simple and inexpensive apparatus for converting carbon monoxide to carbon dioxide, and for burning unburned hydrocarbons.
It is a further object of the invention to provide an element inan automotive exhaust system as noted in the last two foregoing paragraphs which can also serve as a muffler.
In accordance with the present invention, I propose to add an electric resistance heating element, specifically silicon carbide, in the exhaust system of an automobile. The element is electrically heated. Additional air is introduced into the exhaust system forward of the heating element, and the combination of air and heat oxidizes substantially anything in the exhaust gases that is capable of being oxidized, specifically carbon monoxide and unburned hydrocarbons.
DESCRIPTION OF THE DRAWINGS AND DETAILED DISCLOSURE FIG. 1 is a somewhat schematic side view of an automobile showing the present invention as incorporated therein;
FIG. 2 is an enlarged longitudinal sectional view through the smog reducer of the present invention;
FIG. 3 is a longitudinal view generally similar to FIG. 2 showing a modification of the invention adopting it to serve as a muffler as well as a smog reducer; and,
FIG. 4 is a cross-sectional view taken substantially along the line 4-4 in FIG. 3.
Turning now to FIG. 1, there will be seen an automobile 10 having an internal combustion engine 12 with an exhaust pipe 14 connected to a smog reducer 16 comprising the subject matter of the present invention.
The outlet of the smog reducer leads to a more or less conventional muffler 18, which in turn is connected to a tail pipe 20. Although not specifically shown, it will be understood that there is an electrical system associated with the engine 12, including a storage battery and either a generator or an alternator.
Attention now should be directed to FIG. 2 wherein the exhaust pipe 14 will be seen to have at its trailing edge a circumferential, radially extending flange 22..
The exhaust pipe may be insulated at 24 since it is desired to retain the exhaust gases at a high temperature as will be apparent shortly hereinafter. Immediately upstream of the flange 22 the exhaust pipe is provided with a converging air inlet 26 from an air inlet device 28 which is controlled by an exhaust analyzer to be mentioned hereinafter.
The smog reducer 16 comprises a cylindrical tube 30 of silicon carbide. The tube is provided at its inlet end with a circumferential flange 32, and a clamping element or washer 34 is secured to the exhaust pipe flange 22 as by bolts 35 to join the tube 30 to the exhaust pipe 14 in air-tight, coaxial relation. Asbestos or the like gaskets 36 are provided to ensure air tightness.
The tube 30 is provided with a similar flange 40 at its trailing edge, and the tail pipe 20 has a circumferential radially extending flange 42 with bolts 44 extending through a clamping retainer or washer 46 and the flange 42 to hold the tail pipe and the smog reducer 16 tightly together in coaxial relation. Asbestos gaskets 48 again are provided to assure air tightness.
Substantially from end-to-end the tube 30 of the smog reducer is provided with an interior baffle 50 generally in the form of a screw thread. This baffle preferably is cast integrally with the tube 30, and therefore is likewise of silicon carbide construction. Alternatively, the baffle 50 can be of any heat resistant element, such as ceramic, which would then be inserted and held byany suitable means, rather than being integral. As will be understood, if the baffle were made as a separate part, it could be in a plurality of pieces joined en'd-to-end or perhaps with spacers incorporated.
Also, throughout most of the length of the tube 30, and conveniently about the same length as the baffle 50, there is provided exteriorly insulation 52 to prevent escape of heat from the tube. Clamps 54 and 56 provide connection to electric cables 58 and 60 for connection of the electric power source thereto. As will be appreciated the usual alternator or generator in the automobile 10 can be supplanted by one of much higher generating capacity to handle the electric heating of the smog reducing element as well as the other electric requirements of the automobile. In addition, although not specifically shown, it will be understood that any suitable or conventional means as provided for adjusting the current supplied to the silicon carbide tube 30, whereby to control the temperature which will be on the order of many hundreds of degrees Fahrenheit.
In addition to the foregoing, and preferably adjacent the inlet end of the tail pipe 20, there is provided a fitting 62 tapping off a percentage of the exhaust gases to an exhaust analyzer 64. The exhaust analyzer is connected, preferably by electric wires as indicated generally at 66, to the air inlet device 28. The exhaust analyzer will monitor the amount of carbon dioxide and unburned hydrocarbons in the exhaust and also the amount of oxygen present, whereby to control the air inlet device to add more or less air as is necessary for complete combustion of the undesirable unoxidized exhaust components. The exhaust analyzer could also be connected to the current controlling means, but it is at the present time thought unnecessary to be able to make continuous adjustments both of the temperature and of the air, since both can be present to approximately the desired levels, whereby variation of only one is sufficient for final control.
Indeed, it is contemplated that cost of the system could be held down by eliminating the exhaust analyzer and the control function of the air inlet device. At periodic service intervals, such as every three to 6 months, the exhaust could be analyzed in an automotive service station, and the air inlet device could be set manually for the correct results.
A modification of the invention is shown in FIGS. 3
and 4, whereby the smog reducer can serve as a muffler as well as for smog reduction. The system remains generally as heretofore, except for elimination of the muffler, and numerals are used similar to those used heretofore, this time with the addition of the suffix a to avoid duplication of description. The essential difference is that a rod 68 of heat resistant material extends axially through the tube 30a, being held in place by any suitable means such as integral or ceramic spiders within the tube 300. Transverse baffle discs 70 are provided on the rod 68 at suitable intervals. These baffles can be of suitable metallic construction or they can be a ceramic or silica. The purpose is to prevent a straight-through flow path, whereby all of the exhaust gases must travel in a swirling path, thereby substantially eliminating the pulsations which cause obnoxious exhaust sounds. It will be appreciated that the initial form of the invention as discussed with regard to FIG. 2 also effects a swirling path, whereby to ensure proper mixing of the exhaust gases and the added air. However, a more efficient swirling is effected with the use of The specific examples of the invention as herein shown and described will be understood as being for illustrative purposes only. Various changes in structure will no doubt occur to those skilled in the art, and will be understood as forming a part of the present invention insofar as they fall within the spirit and scope of the appended claims.
The invention is claimed as follows:
1. Exhaust treating apparatus for exhaust gases such as from automotive internal combustion engines and the like comprising a conduit for inclusion in an exhaust system, said conduit being made of electric resistance heating material, means for adding air to exhaust gases entering said conduit, means for mixing said added air and exhaust gases, and means connecting a source of electric power to said conduit.
2. Apparatus as set forth in claim 1 wherein the mixing means comprises internal baffle means in spiral configuration and made of an electric resistance heating element, and connected to said source of electric power.
3. Apparatus as set forth in claim 2 wherein the internal baffle means are integral with said conduit.
4. Apparatus as set forth in claim 2 wherein said baffle means are separate and are inserted in said conduit.
5. Apparatus as set forth in claim 1 and further including insulation on the exterior of said conduit.
6. Apparatus as set forth in claim 1 and further including means for adjusting the amount of air added to said exhaust gases in accordance with the composition of gases at the exhaust outlet.
7. Apparatus as set forth in claim 6 and further including means for analyzing the composition of gases at the exhaust outlet and for automatically controlling the amount of air added in accordance therewith.
8. Apparatus as set forth in claim 1 wherein the means for mixing the air and gases comprises a spiral baffle on the internal wall of said conduit and a plurality of transverse baffles spaced longitudinally of said conduit centrally thereof and across the conduit axis and precluding a straight-through flow path, thus enhancing mixing of said air and exhaust gases.
9. Apparatus as set forth in claim 2 wherein said conduit and internal baffle means comprise silicon carbide.