The present invention relates to vehicle exhaust systems. More particularly, the present invention relates to a muffler of a specific design for use in controlling particulate emissions from diesel engines. Prior Art:

Emissions regulations are becoming increasingly stringent for particulates from diesel engines, as well as for gaseous emissions from both conventional and diesel engines. Various mechanisms have been proposed in an effort to reduce emissions.

U.S. Patent No. 4,372,421 to Jackson, the disclosure of which is hereby incorporated by reference, teaches a vehicle exhaust system which incorporates an afterburner, a muffler, and a resonator. The present invention is an improvement on the basic muffler of Jackson and provides a muffler which is particularly suited for filtering diesel exhaust.

SUMMARY OF THE INVENTION

The present invention provides a muffler with improved ability to remove particulates from diesel exhaus .

A muffler in accordance with the present invention comprises:

(a) a hollow housing having an inlet and an outlet and first, second, and third interior port-ions formed therein;

(b) an inlet conduit disposed in the inlet of the housing and extending a distance into the first portion of the housing; the inlet conduit having .a plurality of baffles formed therein, the inlet conduit tapering from a first

cross-sectional diameter at the housing inlet to a second cross-sectionai diameter in the interior of the housing, the second cross-sectionai diameter being smaller than the first cross-sectional diameter;

(c) a mass of sound deadening material disposed in the first portion of the housing surrounding the inlet conduit;

(d) a mass of wire mesh disposed in the second portion of the housing adjacent the mass of sound deadening material ;

(e) an outlet conduit disposed in the outlet of the housing and extending a distance into the third portion of the housing, the outlet conduit having a baffle formed therein; and

(f) a plate in the housing separating the first and second portions thereof, the plate having a plurality of apertures formed therethrough to allow fluid flow communication between the first and second portions of the housin .

For a more complete understanding of the present invention, reference is made to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following description and in the drawings, like reference numbers are used to refer to like parts throughout the several views, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a side elevational view depicting an exhaust system in accordance with the present invention;

Figure 2 is a perspective view showing an afterburner and muffler in accordance with the present invention;

Figure 3 is a cross-sectional view of the afterburner of Figure 2;

Figure 4 is a cut-away, ^' perspective first embodiment of a muffler according to the practice of the present invention,

Figure δ is a cut-aw.ay, perspective view of a resonator which may be employed in the practice of the present invention; and

Figure 6 is a cut-away, perspective view of a second embodiment of a muffler in accordance with the present invention.

DETAILED DESCRIPTION Referring now to the drawings, and in particular Figure 1 , there is shown a vehicle 10 having an exhaust system, generally indicated at 12. The exhaust system includes a conduit 14 extending from the exhaust manifold (not shown), to an afterburner, generally indicated at 16. The conduit 14 extends between the exhaust manifold and the inlet side of the afterburner 16. A conduit 18 extends between the outlet 20 of the after-burner and the inlet 22 of a muffler, generally indicated at 24. An outlet 26 of the muffler 24 is connected to an exhaust pipe, generally indicated at 28. The exhaust pipe 28, in turn, communicates with a resonator, generally indicated at 29. A conduit 31 extends from the resonator and opens to the atmosphere.

It is to be understood that, with reference to the present invention, the automobile 10 is of standard construction and includes a diesel fuel burning internal combustion engine having an exhaust manifold through which the exhaust gases are exhausted to the atmosphere. Further, the conduits which provide the communication between the after-burner, the muffler, the resonator, and the atmosphere are, also, of standard construction and well known to those skilled in the art.

Referring now to Figures 2-δ, there is depicted therein, the afterburner 16, muffler 24, and resonator 29

of the present invention. The after-burner 16 includes a cylindrical steel housing 30 having an outer wail 32 and an inner wall 34. The after-burner further includes a first side wall 38 and a second side wall 40. The two side walls 38, 40 are spaced apart and cooperate with the housing 30 to define an interior chamber 42. A spark plug 44 is threadably mounted in the first side wall 38 of the after-burner 16. The spark plug 44 has a lead wire 46 which extends to the ignition system of the vehicle (not shown) . A contact plate 48. may be mounted in the chamber 42 proximate the spark plug 44.

A pair of support posts 52, 54 are mounted within the housing 30. The support posts are affixed to the housing by any suitable means such as welding or the like. Each of the support posts 52, 54 includes a threaded connector 56 or the like, which extends through the support posts as shown. The two support posts 52, 54 are spaced apart along the longitudinal extent of the housing 30. Extending between the two support posts is a nichrome wire 58. The ends of the nichrome wire 58 are secured to the support posts 52, 54 via the threaded connectors 56. Extending from the support post 52 and its associated threaded connector 56 is a connecting wire 50 which is connected at its other end to the contact plate 48. Thus, the electrical contact achieved by the lead wire 46 is transmitted through connecting wire 50 to the nichrome wire 58. A ground wire 60 extends from the support post 54 to a suitable ground such as the engine block (not shown). In accordance with the present invention, the nichrome wire 58 is adapted to generate approximately a three-ohm resistance to generate heat within the chamber 42. The spark plug 44 is connected for intermittent or continuous flow of electrical current which further, ignites the exhaust gases issuing through the exhaust manifold of the engine. Thus, in accordance with the present invention, the conduit 14

opens into the interior of the housing 30, i.e. , the chamber 42, wherein the heat from the wire 58 and the spark plug 44 cooperate to further combust and break down the exhaust emissions into basic elements, such as carbon dioxide, water, and the .like.

The exhaust gases within the chamber 42 are exhausted through the outlet 20 into the conduit 18. From the conduit 18 the exhaust gases travel to the inlet conduit 22 associated with the muffler 24 hereof. As noted, the muffler of the present invention is particularly suitable for use with a diesel engine.

The muffler 24 includes an inlet 22 and an outlet 26, as hereinbefore noted. The inlet and outlet comprise an inlet conduit 23 and an outlet conduit 25. As shown in Figure 4, the inlet and outlet conduits 23, 25 are generally longitudinally offset in the muffler 24 with respect to the longitudinal axis thereof. A cylindrical casing 64 surrounds the inlet and outlet conduits 23, 25. The flattened casing 64 includes a cylindrical or elliptical wall 66 and end walls 68 and 70 which are substantially planar, the end walls being longitudinally spaced from one another. The interior of the casing 64 is divided into first, second, and third portions thereof as will be further described hereinbelow. The casing 64 may integrally formed with the conduits 23, 25. As shown in Figure 4, the inlet and outlet conduits 23, 25 each have that portion thereof which is disposed within the casing 64 provided with a plurality of baffles 72 formed therethrough. The baffles 72 are openings formed in the wall of the conduits 23, 25 and permit the exhaust gas traveling through the conduits to exit therefrom into the interior of the casing 64, or to pass from the interior of the casing 64 into the outlet conduit 25.

A particularly novel feature of the present invention is the shape of the inlet conduit 23 within the

housing 64. The conduit 23 ^' tapers from a first cross-sectional diameter at the housing inlet 22 to a second cross-sectional diameter in the interior of the housing, adjacent a first separator plate 80. As may be seen in the drawing, - the portion of the inlet conduit 23 within the housing is substantially conical in shape so that the second cross-sectional diameter in the interior of the housing is smaller than the first cross-sectional diameter at the inlet 22 thereof. The inclusion of a sufficient number of baffles 72 in the conical inlet conduit 23 provides escape ports for exhaust gases passing therefrom and does not unduly restrct exhaust flow, as would otherwise be the case, with this tapering design. Thus, because of the baffles 72, back pressure is kept at an acceptable level in the muffler system 12.

Advantages of this conical design of the portion of the inlet conduit 23 within the casing 64 are that this forces more of the exhaust gases out through the baffles 72 and through the material surrounding the inlet conduit 23 to effectively filter the exhaust gas. This is particularly useful with diesel vehicles because of the high particulate content of diesel exhaust. This conical design helps to equalize pressures within the muffler 124 and ensures more effective removal of particulates from diesel exhaust than was possible with the prior art designs. In the embodiment of the present invention showin in Figure 4, the inlet conduit 23 is completely closed off at the second cross-sectional diameter thereof, forcing all of the exhaust gas to pass through the baffles 72 in order to pass through the muffler 24. The first baffle 72 may be advantageously located at a point within the casing 64 where the inlet conduit 40 begins to taper.

Disposed within the interior of the casing 64 and surrounding the inlet conduit 23 is a mass of sound deadening filter material 74, such as fiberglass. The

sound deadening material 74 is utilized in sufficient thickness to fill substantially all of the interior of the first portion 73 of the casing 64. The sound deadening material 74 is held in position and in contact with the inlet conduit 23 by ■an outer layer of wire mesh 76. The portion of the interior of the casing 64 having the sound deadening material 74 disposed therein thus comprises a first interior section 73 of the muffler 24.

Adjacent the insulating material 74 which fills the first section 73 of the interior of the muffler 24 is a second section 75 of the interior. The second section 75 is filled with a plurality of turns of fine wire mesh 76 which are disposed within the interior of the casing 64. Thus, the gases which exit from the first portion of the casing, come into contact with the wire mesh 76 in the second portion thereof.

A perforated plate 80 is disposed between the first and second section of the interior of the muffler 24. The plate 80 includes a plurality of apertures or openings 81 which permit exhaust gases to flow from the first interior section 73 into the second interior section 75. Similarly, a second perforated plate 83 is disposed at the rearward end of the second section 75 of the interior of the casing 64. The second plate 83 helps to retain the wire mesh 76 within the second section 75 of the muffler 24 while allowing exhaust gases to pass therethrough. The second perforated plate 83 has a plurality of apertures or openings 85 formed therein to permit exhaust gas flow therethrough. A third section 77 of the interior of the muffler 24 rearward of the second perforated plate 83 defines an air space within the muffler 24. The insulation 74 and wire mesh 76 define a removable module or cartridge that can be easily removed from the muffler 24 and replaced with a fresh cartridge to prevent clogging of the insulation and wire mesh with particulates. The removable

feature is achieved by providing a plurality of fasteners such as bolts 79, which connect one end wall 68 to the cylindrical wall 66. Thus, the bolts 79 can be detached, thereby permitting the end wail 68 to be removed. The inlet conduit 23 is -fixedly attached to the end wall 68, and thus comes away and is detachable with the end wall 68. This allows for easy access to the interior of the muffler 24 for removal of the fiberglass and wire mesh therein. The first perforated plate 80 may be reused, or, alternatively, may be replaced with a new cartridge. As noted, the exhaust port 26 of the muffler 24 is connected to the exhaust pipe 28 which then transmits the gases to the resonator 29. The resonator 29 is optional. The resonator 29 is constructed in a manner somewhat similar to that of the muffler 124. As shown in Figure 5 the resonator generally includes a pair of spaced apart end walls 82, 84 and a substantially cylindrical side wall 86 fixedly attached thereto. The walls cooperate to define an open interior 88. The end wall 82 is provided with an opening 90 which defines an inlet for the exhaust pipe 28. The exhaust pipe 28 is baffled along the extent thereof as herein described with respect to the muffler 24.

The interior of the resonator 29 is separated into two sections. The first section is defined by a fiberglass or mat 94 which surrounds the conduit 28. The second section of the interior 88 of the resonator 29 comprises a wire mesh or screen 98. The wire mesh 98 surrounds the fiberglass matt 94. It is to be appreciated that as exhaust gases enter the conduit 28 they are circulated through the interior 88 of the resonator 29 by virtue of the baffles. Unlike the design in the muffler 124, in the resonator 29 the exhaust gas does not have to pass through the fiberglass packing to exit the unit. The resonator 29 further includes an outlet 100 which is defined by an

opening in the end wall 84. The conduit 28 is connected to the exhaust conduit at the outlet 100. A second embodiment of a muffler 124 may be substituted for the muffler 24 in the exhaust system 12 of the present invention.

Referring now • to Figure 6, a second embodiment of a muffler 124 in accordance herewith, generally, comprises a substantially cylindrical housing 164 having a tubular side wall 166 and two end walls 168, 170 affixed to the side wall 166. One of the end walls 168 is removably attached to the side wall .166 by threaded fasteners 179 such as bolts, screws, or the like. The muffler 124 includes an inlet 122 and an outlet 126 formed in the end walls 168, 170, respectively. An inlet conduit 123 is disposed in the inlet 122 and fixedly attached thereto, and in a similar fashion, an outlet conduit 125 is disposed in the outlet 126 and is fixedly attached thereto. As shown in Figure 6, in this embodiment, the inlet and outlet conduits 123, 125 are, generally, coaxially and linearly disposed in the housing 164 along the longitudinal axis thereof.

The interior of the casing 164 is divided into first, second, and third portions as will be further discussed herein. As shown in the drawing, the inlet and outlet conduits 123, 125 each have that portion thereof which is disposed within the casing provided with a plurality of baffles 172 formed therethrough. The baffles 172 are openings formed in the wall of the conduits 123, 125 to permit exhaust gases traveling through the conduits 123, 125 to exit therefrom into the interior of the casing 164, or to pass from the interior of the casing 164 into the outlet conduit 125.

Once again, in this embodiment, the inlet conduit 123 tapers in a substantially conical shape from a first, larger, cross-sectional diameter at the housing inlet 122 to a second, smaller, cross-sectional diameter in the

interior of the housing, adjacent a separator plate 180. The inclusion of a sufficient number of baffles 172 in the inlet conduit 123 provides escape ports for exhaust gases to pass through from the conduit 123 and does not unduly restrict exhaust flow,- as would otherwise be the case with such a conical design. Thus, because of the presence of the baffles 172, back pressure within the muffler system 12 is kept at an acceptable level, allowing the diesel engine (not shown) in the vehicle 10 to perform more effectively than it would without the baffles 172.

The conical design of the inlet conduit 123 forces a significant portion of exhaust gases out through the baffles 172 and through a filter material 174, which surrounds the inlet conduit 123, to effectiλ'ely filter the exhaust gas.

Again, this design is particularly efficacious for use w ^τ ith diesel engines, because of the known high particulate content of diesel exhaust. In the embodiment of Figure 6, a. central opening 202 is provided in the separator plate 180 to allow some of the exhaust gas to pass directly from a first portion 173 to a second portion of the muffler 124 without passing through the baffles 172 and the filter medium 174. In this embodiment, less than all of the exhaust gas is required to pass through the baffles 172 in order to pass through the muffler 124, as distinguished from the design shown in Figure 4.

Disposed within the interior of the casing 164 and surrounding the inlet conduit 123 is a mass of filter material 174, such as, e.g. , fiberglass. The filter material 174 is provided in sufficient thickness to fill substantially all of the first portion 173 of the casing 164. The filter material 174 is the only material within the first portion 173 of the casing 164 surrounding the inlet conduit 123 in this second embodiment.

A second interior section 175 of the muffler 124

is defined by the space between the perforated plate 180 and a foraminous plate 183 disposed within the casing 164. The foraminous plate 183 has a plurality of openings 185 formed therethrough and serves to retain a wire mesh 176 in the second section of- the muffler to screen particulates out of the exhaust, while allowing gases to pass through.

A third section 177 of the interior of the muffler casing 164 rearward of the foraminous plate 183 defines an air space within the muffler 124. The filter material 174 and wire mesh 176 define a-removable module or cartridge that can be easily removed from the muffler 124 and replaced with a fresh cartridge to prevent clogging of the muffler 124 with particulates.

The opposite end of the exhaust conduit opens to the atmosphere. The improved design of the present invention significantly reduces particulate emissions from a diesel engine ^• when installed as part of a complete exhaust system.

Having, thus, described the invention, what is claimed is: