Catalytic converter for motor vehicles

• US 5,482,681 A
• Filed: 09/03/1991
• Issued: 01/09/1996
• Est. Priority Date: 09/20/1985
• Status: Expired due to Fees

• Current Assignee: Tenneco Automotive Operating Company Incorporated (Apollo Global Management, Inc.)
• Original Assignee: Tennessee Gas Pipeline Company (El Paso Corporation)
• Inventors: Sager, Robert L. Jr.
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): Kim, Christopher Y.
• Application Number:
  US07/754,042
• Time in Patent Office: 1,589 Days
• Field of Search: 422/177, 422/180, 422/182, 422/202, 181/241, 181/243, 181/282, 181/283
• US Class Current: 422/180
• CPC Class Codes: F01N 13/0097 the purifying devices are arranged in a single housing
• CPC Class Codes: F01N 13/14 having thermal insulation exhaust manifolds F01N13/102
• CPC Class Codes: F01N 13/1888 the housing of the assembly consisting of two or more parts, e.g. two half-shells
• CPC Class Codes: F01N 2260/022 using air
• CPC Class Codes: F01N 2450/30 Removable or rechangeable blocks or cartridges, e.g. for filters
• CPC Class Codes: F01N 3/2857 the mats or gaskets being at least partially made of intumescent material, e.g. unexpanded vermiculite
• CPC Class Codes: F01N 3/30 Arrangements for supply of additional air control, e.g. using by-passes or variable air pump drives, F01N3/22
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

An aftermarket catalytic converter for motor vehicle exhaust gas systems has a clamshell housing with an upper heat shield and stainless steel inlet and outlet bushings and contains a catalyst coated substrate cushioned and supported inside of it by a heat expandable mat, the features and parts of the converter being constructed and arranged to enable one converter construction to be used as a replacement converter in a substantial number of different applications for the original equipment converters.

Claims

1. A motor vehicle exhaust gas system aftermarket catalytic converter suitable as a replacement for a variety of original equipment ("O.E.") catalytic converters, said aftermarket catalytic converter comprising a clamshell housing comprised of upper and lower halves each about 10 inches long and having a peripheral rim including semicircular rim sections at opposite ends and longitudinal rim sections extending between said semicircular rim sections, said longitudinal rim sections being welded together and said halves being shaped to jointly form a housing having a centrally located longitudinally extending catalyst substrate chamber about 5.75 inches long, said semicircular rim sections fitting together to define a circular inlet flange and a circular outlet flange, said housing including an inlet chamber increasing in cross-section in a direction extending from the circular inlet flange to an upstream end of said substrate chamber, said housing including an outlet chamber decreasing in cross-section in a direction extending from a downstream end of the substrate chamber to said circular outlet flange, a cylindrical inlet bushing having a downstream end fitting in and welded to said circular inlet flange, a cylindrical outlet busing having an upstream end fitted in and welded to said circular outlet flange, said bushings having a diameter of about 2.0 to 2.5 inches and projecting outwardly about 1.5 to 2.0 inches from said semicircular rim sections whereby the overall length of the housing is about 13 to 14 inches, said housing being substantially symmetrical about a longitudinal axis and said circular flanges and said bushings being substantially concentric with said longitudinal axis, a clamshell heat shield conforming in shape to the upper half of said housing, said heat shield including flat longitudinal side flanges welded to the longitudinal rim sections of said housing and a semicircular section extending laterally between the side flanges and completely spaced from and unconnected to the semicircular rim sections of the housing to provide an uninterrupted insulation space between the opposite ends of the shield, and oval-shaped flat ended catalyst substrate of the catalyst coated honeycomb-type disposed in said substrate chamber, an annular uniform thickness substrate support mat surrounding the entire outer peripheral surface of said substrate and in engagement with the wall of the chamber to centrally locate and support the substrate in the chamber and substantially uniformly space the outer peripheral surface of the substrate about 0.125 inch from the walls of the chamber, said support mat being composed of a heat expandable vermiculite base material and compressed between the walls of the chamber and the outer peripheral surface of the substrate to about one-half of its preassembled free state thickness, said substrate being about 4.25 inches long and having a major height of about 3.0 inches, a major width of about 4.75 inches, and a volume of about 55 cubic inches, said substrate having a multiplicity of longitudinally extending exhaust gas passage honeycomb cells at a density of substantially 400 cells per square inch, the walls of said cells being coated with a catalyst effective in the reduction of oxides of nitrogen and the oxidation of hydrocarbons and carbon monoxide, said catalyst comprising substantially five parts palladium and one part rhodium applied in a coating of about 20 grams per cubic foot of substrate.

2. A converter as set forth in claim 1 wherein the major height of said clamshell housing is about 31/2", and the major height of said heat shield and said converter is about 33/4".

3. A motor vehicle exhaust gas system aftermarket catalytic converter suitable as a replacement for a variety of original equipment ("O.E.") catalytic converters, said aftermarket catalytic converter comprising a clamshell housing about 3.5 inches high comprised of upper and lower halves each about 10 inches long and having a peripheral rim including semicircular rim sections at opposite ends and longitudinal rim sections extending between said semicircular rim sections, said longitudinal rim sections being welded together and said halves being shaped to jointly form a housing having a centrally located longitudinally extending uniform size oval cross-section catalyst substrate chamber about 5.75 inches long, said semicircular rim sections fitting together to define a circular inlet flange and a circular outlet flange, said housing including an inlet chamber increasing in cross-section in a direction extending from the circular inlet flange to an upstream end of said substrate chamber, said housing including outlet chamber decreasing in cross-section in a direction extending from a downstream end of the substrate chamber to said circular outlet flange, a cylindrical inlet bushing having a downstream end fitting in and welded to said circular inlet flange, a cylindrical outlet bushing having an upstream end fitted in and welded to said circular outlet flange, said bushings projecting outwardly about 1.5 to 2.0 inches from said semicircular rim sections whereby the overall length of the upper housing is about 13 to 14 inches, said housing being substantially symmetrical about a longitudinal axis and said circular flanges and said bushings being substantially concentric with said longitudinal axis, a clamshell heat shield conforming in shape to said upper housing half and secured thereto solely by longitudinal side flanges being welded to the longitudinal rim sections of the housing said heat shield forming a continuous uninterrupted semicircular shell, portion above said upper housing half and providing an insulation space open at opposite ends of said shell, an oval-shaped flat ended catalyst substrate of the catalyst coated honeycomb-type in said substrate chamber, an annular uniform thickness substrate support mat surrounding the entire outer peripheral surface of said substrate and in engagement with the wall of the chamber to centrally locate and support the substrate in the chamber and substantially uniformly space the outer peripheral surface of the substrate about 0.125 inch from the walls of the chamber, said support mat being composed of a heat expandable vermiculite base material and compressed between the walls of the chamber and the outer peripheral surface of the substrate to about one-half of its preassembled free state thickness, said oval cross-section substrate being about 4.25 inches long and having a major height of about 3.0 inches, and a major width of about 4.75 inches and a volume of about 55 cubic inches, said substrate having a multiplicity of longitudinally extending exhaust gas passage honeycomb cells at a density of substantially 400 cells per square inch, the walls of said passages being coated with a catalyst effective in the reduction of oxides of nitrogen and the oxidation of hydrocarbons and carbon monoxide, said catalyst comprising substantially five parts palladium and one part rhodium applied in a coating of about 20 grams per cubic foot.

4. A converter as set forth in claim 3 wherein said heat shield and said converter have a major height of about 33/4".

5. A motor vehicle exhaust gas system aftermarket catalytic converter suitable as a replacement for a variety of original equipment ("O.E.") catalytic converters comprising a clamshell housing comprised of upper and lower halves including flat longitudinal rim sections extending between semicircular rim sections, the longitudinal rim sections being welded together to jointly form a housing substantially symmetrical about a longitudinal axis and having a centrally located longitudinally extending uniform size oval cross-section catalyst substrate chamber, said longitudinal and semicircular rim sections at opposite ends of the housing fitting together to define a circular inlet flange and a circular outlet flange, a circular cylindrical inlet bushing fitting in and welded to said circular inlet flange, a circular cylindrical outlet bushing fitting in and welded to said circular outlet flange, catalyst means including an oval-shaped flat ended catalyst substrate in said substrate chamber for reacting with exhaust gases passed through the housing, support means comprising an annular uniform thickness substrate support mat composed of a heat expandable vermiculite base material for surrounding and substantially uniformly spacing the substrate from the walls of the chamber, said converter further characterized by said housing halves each being about 10 inches long and said bushings having inner diameters in the range of 2.0 to 2.5 inches and projecting outwardly a distance in the range of 1.5 to 2.0 inches from the semicircular rim sections of said housing whereby the overall length of the housing and bushings is in the range of 13 to 14 inches, a clamshell heat shield conforming in shape to said upper housing half and connected to said housing only along the longitudinal rim sections of said upper housing half, said shield including longitudinal peripheral flanges welded to the longitudinal rim sections of said housing, and a semicircular housing section spaced from the semicircular rim sections of the housing and spaced above the upper half of the housing to provide an insulation space open at opposite ends of the housing section, said substrate having extended between its opposite end faces a multiplicity of longitudinally extending exhaust gas passages each coated with a catalyst effective in the reduction of oxides of nitrogen and the oxidation of hydrocarbons and carbon monoxide.

6. A converter as set forth in claim 5 including inlet means for injecting air into said catalyst chamber, said inlet means comprising a tubular member having opposite end portions with one end portion being secured in sealed relation to one clamshell half of said housing at a location spaced from said longitudinal rim sections.

7. A converter as set forth in claim 6 including a pair of coaxial, axially spaced substrates, and wherein said tubular member includes an apertured portion which extends into the axial space formed between said substrates.

8. A converter as set forth in claim 5 wherein said clamshell housing is about 31/2" high and said heat shield and said converter having a total height of about 33/4".

9. In a catalytic converter of the type used in motor vehicle exhaust systems, a housing of the clam-shell type and open at each end, said housing including upper and lower shell halves having mating flanges extending longitudinally along respective shell edges, a reducing catalyst substrate and an oxidizing catalyst substrate disposed in said housing, support means, including a resilient support mat encircling each said substrate, for securing and locating the substrates in said housing relative to the respective ends of the housing and such that the substrates are axially spaced from one another whereby to form a central chamber, means for communicating air into said central chamber from a source external to said housing to aid in the oxidation and reduction process as exhaust gases are passed through the housing, and heat shield means comprising a single one piece sheet of material conforming in shape to the upper shell half of said housing and extending longitudinally in superposing relation above the housing, said sheet of material including longitudinal peripheral rim sections welded to said longitudinal mating flanges of the housing with the rim sections and mating flanges being disposed in a common plane passing through the central axis of the housing.

10. The converter as recited in claim 9 wherein said means for communicating air comprises an elongated tube having opposite end portions and perforations disposed therealong, and means for securing one end portion of said tube into the wall of extending through said housing, the other end portion of said tube being spaced from the interior surface of the housing and the end thereof opening, into said central chamber.

11. In a catalytic converter for internal combustion exhaust gases and of the type having catalyst means mounted in a housing of the clamshell type and open at each end, said housing being comprised of an upper and a lower shell member having mating flanges which are sealingly welded together and extend longitudinally along opposite sides thereof, and means for communicating air into said housing for oxidation of the exhaust gases, the improvement comprising said catalyst means including a pair of oval-shaped flat ended substrates, one and the other substrate being, respectively, a reducing substrate and an oxidizing substrate, support means for mounting the substrates in said housing such that the outer peripheral surfaces of the substrates are spaced from the walls of the housing and located in axially spaced relation to define a chamber between respective end faces, said means for communicating air into the housing comprises an elongated tube having perforations disposed between its opposite end portions, one end portion being secured to one said shell member at a location spaced from said mating flanges and the other end portion opening into said chamber, and a clamshell heat shield comprising a single one piece sheet of material having longitudinal peripheral rim sections and extending longitudinally between opposite longitudinal ends, said sheet conforming in shape to said upper shell member and being connected to the housing solely by said longitudinal peripheral rim sections being welded to the mating flanges of said housing and including semicircular rim sections at said opposite ends, said semicircular rim sections being formed by a continuous uninterrupted edge of said sheet that extends between said longitudinal rim sections and is spaced from the housing to provide an insulation space open at opposite ends.