Exhaust assembly for utility vehicle

Abstract

A utility vehicle includes an exhaust assembly fluidly coupled to an engine. Depending on various parameters, such as the size and / or performance of the vehicle, the exhaust assembly needs to meet certain emissions regulations. Such emissions regulations can be met by increasing the temperature within the exhaust assembly, however, at particularly high temperatures, a catalyst of the exhaust assembly can be damaged. Accordingly, the exhaust assembly includes various options for cooling portions thereof to remove heat from the assembly.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 184,496, filed May 5, 2021, entitled “EXHAUST ASSEMBLY FOR A UTILITY VEHICLE” (Attorney Docket No. PLR-06-29264.01P-US), the entire disclosure of which is expressly incorporated by reference herein. TECHNICAL FIELD

[0003] The present disclosure relates generally to an exhaust assembly for a vehicle, and more particularly to an exhaust assembly for a utility or off-road vehicle that is configured to reduce emissions from the utility or off-road vehicle. BACKGROUND

[0004] Off-road vehicles are typically smaller than automotive vehicles and are not classified under automotive standards and regulations. As such, off-road vehicles can have different emission regulations as compared to automotive emission regulations. However, if various parameters of the off-road vehicle, such as the size of the vehicle, the performance of the vehicle, and the like, change, the vehicle can be required to meet different emission standards. As emission standards change in the United States, Europe, and other parts of the world, there is a need to provide an off-road vehicle that is configured for improved performance and is capable of meeting more stringent emission regulations. SUMMARY

[0005] In one embodiment of the present disclosure, a utility vehicle includes a frame assembly extending along a longitudinal axis and defining an operator area, a plurality of ground-engaging members supporting the frame assembly and including a front ground-engaging member and a rear ground-engaging member, a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine, and an exhaust assembly including an exhaust conduit fluidly coupled to the engine, a catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit, and a cooling mechanism configured to provide a cooling fluid to a portion of the exhaust assembly.

[0006] Preferably, the cooling mechanism defines a deflection mechanism configured to direct bypass air through a portion of the utility vehicle and toward the exhaust assembly.

[0007] Preferably, the cooling mechanism includes a radiator configured to provide the cooling fluid to the engine.

[0008] Preferably, the cooling mechanism includes a fan.

[0009] Preferably, the cooling mechanism comprises an outlet port of the transmission.

[0010] Preferably, the cooling mechanism comprises a cooler configured to provide cooling fluid to the transmission.

[0011] Preferably, the cooling mechanism includes a deflection mechanism positioned at the wheel wells of the rear contact members.

[0012] Preferably, the cooling mechanism comprises a cooling jacket.

[0013] Preferably, the cooling jacket is located along a portion of the exhaust duct.

[0014] Preferably, the cooling jacket is fluidly coupled to a cooling circuit, and the cooling circuit comprises a heater for the operator area.

[0015] Preferably, the cooling circuit comprises a first cooling circuit, and a second cooling circuit is operatively coupled to the engine and is distinct from the first cooling circuit.

[0016] Preferably, the exhaust assembly further includes an exhaust manifold fluidly coupled with the engine and the exhaust conduit, and the cooling jacket is positioned along a portion of the exhaust manifold.

[0017] Preferably, the catalyst includes a first catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit, and further includes a second catalyst positioned downstream of the first catalyst along the exhaust conduit.

[0018] Preferably, the second catalyst is positioned within the muffler of the exhaust assembly.

[0019] Preferably, the first catalyst is equal to or smaller in size than the second catalyst.

[0020] In another embodiment, a method of cooling a portion of an exhaust assembly of an engine for a utility vehicle includes providing an exhaust conduit; fluidly coupling a catalyst to the exhaust conduit; directing a fluid at a portion of the exhaust assembly; and reducing a temperature of exhaust gas flowing through the exhaust assembly after directing the fluid at the portion of the exhaust assembly.

[0021] Preferably, directing the fluid includes directing bypass air through a portion of the utility vehicle and toward the portion of the exhaust assembly.

[0022] Preferably, directing the fluid includes directing air through a radiator fluidly coupled to the engine and toward the portion of the exhaust assembly.

[0023] Preferably, directing the fluid includes directing air through the fan and toward the portion of the exhaust assembly.

[0024] Preferably, the method further includes providing a transmission operably coupled to the engine, and wherein directing the fluid includes discharging air from the transmission and directing the air toward the portion of the exhaust assembly.

[0025] Preferably, directing the fluid includes flowing the fluid through a cooling jacket positioned at the portion of the exhaust assembly.

[0026] Preferably, the method further includes providing an exhaust manifold fluidly coupled to the engine and the exhaust conduit and positioning the water jacket along a portion of the exhaust manifold.

[0027] In yet another embodiment, an utility vehicle includes a frame assembly extending along a longitudinal axis and defining an operator area, a plurality of ground engaging members supporting the frame assembly and including a front ground engaging member and a rear ground engaging member, a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine, and an exhaust assembly including an exhaust conduit fluidly coupled to the engine, a first catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit, and a second catalyst positioned along the exhaust conduit downstream of the first catalyst.

[0028] In another embodiment, an utility vehicle includes a frame assembly extending along a longitudinal axis and defining an operator area, a plurality of ground engaging members supporting the frame assembly and including a front ground engaging member and a rear ground engaging member, a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine, and an exhaust assembly including an exhaust conduit fluidly coupled to the engine, and a catalyst fluidly coupled to exhaust conduit and configured to receive exhaust gas from the exhaust conduit, and the exhaust conduit, the engine, and the catalyst positioned adjacent one another along the longitudinal axis.

[0029] Preferably, the exhaust conduit is positioned longitudinally intermediate the engine and the catalyst.

[0030] Preferably, the catalyst is positioned longitudinally intermediate the engine and the exhaust conduit.

[0031] Preferably, the exhaust assembly further includes an exhaust gas constituent sensor supported by the exhaust conduit, and the exhaust gas is continuous between the exhaust gas sensor and the catalyst.

[0032] Preferably, the sensor is positioned downstream of the catalyst.

[0033] Preferably, the exhaust assembly further comprises a heat shield positioned adjacent the sensor.

[0034] Preferably, at least a portion of the heat shield is separated from the muffler by an air gap.

[0035] Preferably, the exhaust assembly further includes a muffler, and the exhaust duct includes a bellows, and the bellows is positioned within the utility vehicle at a position longitudinally intermediate the muffler and the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other features of the present invention and the manner in which they are achieved will become more apparent, and the present invention itself will be better understood, by referring to the following description of the embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0037] FIG. 1 is a left front perspective view of a utility vehicle of the present disclosure;

[0038] FIG. 2 yes FIG. 1 a right rear perspective view of a utility vehicle;

[0039] FIG. 3 yes FIG. 1 left side view of a utility vehicle;

[0040] FIG. 4 yes FIG. 1 a right side view of a utility vehicle;

[0041] FIG. 5 yes FIG. 1 a top view of a utility vehicle;

[0042] FIG. 6 yes FIG. 1 A front view of a utility vehicle;

[0043] FIG. 7 yes FIG. 1 a rear view of a utility vehicle;

[0044] FIG. 8A yes FIG. 1 a schematic top view of a layout of powertrain components of a utility vehicle;

[0045] FIG. 8B yes FIG. 1a top view of a utility vehicle of the type

[0046] FIG. 8C is FIG. 1 a top view of a utility vehicle of the type

[0047] FIG. 8D is FIG. 1 a top view of a utility vehicle of the type

[0048] FIG. 9 is FIG. 8B and FIG. 8D a left front perspective view of a continuously variable transmission of a powertrain assembly of the type

[0049] FIG. 10 is FIG. 8B a top view of a powertrain assembly and exhaust assembly of the type

[0050] FIG. 11 is FIG. 8D a top view of a powertrain assembly and exhaust assembly of the type

[0051] FIG. 12 is a schematic view of an exhaust assembly of the present disclosure having a first oxygen sensor;

[0052] FIG. 13 is a schematic view of an exhaust assembly of the present disclosure having a second oxygen sensor;

[0053] FIG. 14 is FIG. 13 a cross-sectional view of a muffler of an exhaust assembly of the type

[0054] FIG. 15 is FIG. 14 a schematic view of an exhaust assembly of the type having a third oxygen sensor;

[0055] FIG. 16 is a right rear perspective view of an alternative embodiment muffler of an exhaust assembly disclosed herein;

[0056] FIG. 17 is FIG. 16 a cross-sectional view of a muffler of the type

[0057] FIG. 18 is a schematic view of a first cooling embodiment of an exhaust assembly disclosed herein;

[0058] FIG. 19 is a schematic view of a second cooling embodiment of an exhaust assembly disclosed herein;

[0059] FIG. 20 is a schematic diagram of a third cooling embodiment of an exhaust assembly disclosed herein;

[0060] FIG. 21 is a schematic diagram of a fourth cooling embodiment of an exhaust assembly disclosed herein;

[0061] FIG. 22 is a schematic diagram of a fifth cooling embodiment of an exhaust assembly disclosed herein;

[0062] FIG. 23 is a schematic diagram of a sixth cooling embodiment of an exhaust assembly disclosed herein;

[0063] FIG. 24 is a schematic diagram of a seventh cooling embodiment of an exhaust assembly disclosed herein;

[0064] FIG. 25 is a schematic diagram of an eighth cooling embodiment of an exhaust assembly disclosed herein;

[0065] FIG. 26 is a schematic diagram of a ninth cooling embodiment of an exhaust assembly disclosed herein;

[0066] FIG. 27 is a schematic diagram of a tenth cooling embodiment of an exhaust assembly disclosed herein;

[0067] FIG. 28 is a schematic diagram of an eleventh cooling embodiment of an exhaust assembly disclosed herein;

[0068] FIG. 29 Is not used FIG. 28 A schematic diagram of a conventional exhaust duct length of an eleventh cooling embodiment;

[0069] FIG. 30 It is the use of FIG. 28 A schematic diagram of an extended length of the exhaust duct of an eleventh cooling embodiment;

[0070] FIG. 31 It is the use of FIG. 28 Another schematic diagram of the extended length of the exhaust duct of the eleventh cooling embodiment;

[0071] FIG. 32 yes FIG. 1 a rear perspective view of a portion of the vehicle's engine and alternator;

[0072] FIG. 33 yes FIG. 32 Rear perspective view of the alternator and fan;

[0073] FIG. 34 yes FIG. 33 Exploded view of the alternator and fan;

[0074] FIG. 35 is a schematic view of a cooling air flow across a portion of an engine and alternator and at least a portion of the exhaust assembly disclosed herein in a rearward direction; FIG. 32

[0075] FIG. 36 is a top view of an engine and exhaust assembly disclosed herein;

[0076] FIG. 37 is a partial exploded view of a portion of an exhaust assembly disclosed herein;

[0077] FIG. 38 is a right side view of a muffler of an exhaust assembly disclosed herein;

[0078] FIG. 39 is a left side view of a muffler of FIG. 38

[0079] FIG. 40 is a top view of a muffler of FIG. 36

[0080] FIG. 41 is a perspective view of a muffler disclosed herein and showing a heat shield for an exhaust composition sensor;

[0081] FIG. 42 is a cross-sectional view of a muffler of FIG. 41 taken along line 42-42 of FIG. 41

[0082] FIG. 43 is a partial exploded view of a muffler and heat shield of FIG. 41

[0083] Throughout the drawings, corresponding reference characters indicate corresponding parts. The drawings are to scale unless otherwise specified. DETAILED DESCRIPTION

[0084] The embodiments disclosed below are not intended to be exhaustive or to limit the invention to the precise form disclosed in the following detailed description. Rather, the embodiments were chosen and described from among a wide number of possible embodiments so as to provide the best understanding of the principles and the practices of the present invention. Although the present disclosure is primarily directed to utility vehicles, it should be appreciated that the features disclosed herein can be applied to any vehicle having one or more ground engaging members, including but not limited to all-terrain vehicles, motorcycles, snowmobiles, scooters, tricycles, and golf carts.

[0085] Referring to FIGS. 1-7 ​​​​​, showing an illustrative embodiment of a utility vehicle 2. The vehicle 2 is configured for off-road operation. The vehicle 2 includes a plurality of ground-engaging members 4, illustratively front wheels 6 and rear wheels 8. In one embodiment, one or more of the ground-engaging members 4 can be replaced by a track, such as the Prospector II track available from Polaris industries, Inc. of 2100 Highway 55 in Medina, MN 55340; or by a non-pneumatic tire, such as those shown in U.S. Patent Nos. 8,176,957 and 8,104,524, the entire disclosures of which are expressly incorporated by reference herein.

[0086] The vehicle 2 further includes a frame assembly 10 supported by the ground-engaging members 4, the frame assembly extending along a longitudinal axis L of the vehicle 2 FIG. 8B ). The frame assembly 10 includes a lower frame assembly 12 and an upper frame assembly 14 coupled together. The upper frame assembly 14 generally extends above the lower frame assembly 12. The frame assembly 10 supports a rear cargo area 22 and a vehicle body 20 including a plurality of vehicle body panels, such as a hood.

[0087] The vehicle 2 also includes an open operator area 16, illustratively including seats 18 for one or more passengers. As such, the operator area 16 is exposed to ambient air and is not fully enclosed. Alternatively, the vehicle 2 can include a cab assembly (not shown), such as a roof, a front windshield, a rear windshield, and doors, to enclose the operator area 16. The upper frame assembly 14 can be positioned generally about the operator area 16 such that the seats 18 are at least partially surrounded by the upper frame assembly 14. Illustratively, the seats 18 include an operator seat and a passenger seat, however, the seats 18 can also include a rear bench seat for additional passengers, or can include only a single seat for carrying an operator. The seats 18 can include a seat bottom 18a and a seat back 18b.

[0088] The operator area 16 further includes a plurality of operator controls 28, such as a steering wheel, through which an operator can provide input to operate the vehicle 2. Various operator controls, including a steering assembly, can be further described in International Patent Application No. PCT / US13 / 64516 (Attorney Docket No. PLR-15-25448.04P-WO), filed on October 11, 2013, the entire disclosure of which is expressly incorporated by reference herein.

[0089] Still referring to FIGS. 1-7The vehicle 2 includes a rear suspension assembly 24 and a front suspension assembly 26, both of which are supported by the lower frame assembly 12. Additional details of the suspension assemblies 24, 26 can be disclosed in U.S. Patent No. 9,566,858, issued February 14, 2017 (Attorney Docket No. PLR-15-26601.01P) and U.S. Patent Application Serial No. 16 / 226,797, filed December 20, 2018 (Attorney Docket No. PLR-15-28340.05P-US), the entire disclosures of which are expressly incorporated herein by reference.

[0090] Referring to FIGS. 8A-8D The vehicle 2 further includes a powertrain assembly 30, which is supported by the lower frame assembly 12 and includes at least a prime mover (illustratively an engine 32), a transmission (which can be configured as or include a manual transmission 36), a continuously variable transmission (“CVT”) 34, and an intake assembly 38. The powertrain assembly 30 can be located in different positions within the vehicle 2, as shown by the various dashed depictions of the powertrain 30. While the vehicle 2 is illustratively shown as including the powertrain components listed above, the vehicle 2 is not so limited and can include any powertrain arrangement. The powertrain assembly 30 further includes primary reducers or differentials, such as a front drive 39 and a rear drive 37. The rear drive 37 is operably coupled to the rear ground-engaging members 8 by half shafts, and similarly, the front drive 39 is operably coupled to the front ground-engaging members 6 by half shafts.

[0091] The engine 32 is positioned rearward of the operator area 16 and generally rearward of the seat 18. While the prime mover is disclosed as an engine 32, the prime mover can be any type of device configured to provide power to the vehicle 2, such as an electric motor, a fuel-based engine, a hybrid engine, a generator, etc. The engine 32 can be any size and include any number of cylinders 31, such as one cylinder, two cylinders, three cylinders, four cylinders, six cylinders, or eight cylinders. The intake assembly 38 is fluidly coupled to an intake manifold of the engine 32 to provide combustion air thereto.

[0092] Further, the CVT 34 and the range transmission 36 are at least partially located rearward of the operator area 16 and the seat 18. The CVT 34 is operably coupled to both the engine 32 and the range transmission 36. More specifically, the CVT 34 is operably coupled to the engine 32 by a crankshaft (not labeled) of the engine 32 and to the range transmission 36 by an input shaft (not labeled) of the range transmission 36. In various embodiments, the CVT 34 can be positioned longitudinally forward of the engine 32 or laterally outward of at least a portion of the engine 32. The range transmission 36 can also be positioned longitudinally forward or rearward of the engine 32 or laterally outward of at least a portion of the engine 32.

[0093] As shown in FIG. 9 The CVT 34 includes a housing 50 having an inner portion or cover 52 and an outer portion or cover 54 removably coupled together. The CVT housing 50 includes a single air intake or inlet port 56 for receiving air to cool the CVT 34 and a single air exhaust or outlet port 58 for expelling warm or hot air from the CVT 34. Illustratively, the outer cover 54 includes the air inlet port 56 and the inner cover 52 includes the air outlet port 58. As known, the CVT 34 includes a drive pulley or belt wheel, a driven pulley or belt wheel, and a belt (not shown) extending therebetween. In one embodiment of the CVT 34, the belt is a rubber belt, however, in other embodiments of the CVT 34, the belt is a steel belt.

[0094] Because the vehicle 2 is configured for off-road applications, the powertrain assembly 30 including the exhaust assembly 40 can have a reduced potential length of exhaust heat after the catalyst of the exhaust assembly 40 (due to the powertrain assembly 30 being generally located rearward of at least a portion of the operator area 16), a higher load duty cycle compared to typical on-road passenger vehicle usage profiles, a higher engine specific power (Hp / L) which can result in increased exhaust gas temperatures, a potential increase in higher vibration / mechanical shock loads due to the vehicle 2 being capable of jumping, and / or more exposure to debris (e.g., dirt, mud, grass). As such, given the above, the exhaust assembly 40 can be configured as disclosed herein.

[0095] Referring again to FIGS. 8B-8DThe vehicle 2 further includes an exhaust assembly 40 fluidly coupled with the powertrain assembly 30, and more particularly, with the engine 32. The exhaust assembly 40 includes a muffler 42, an exhaust manifold 44, an exhaust conduit 46, and a tailpipe or outlet 48. Illustratively, the exhaust manifold 44 is coupled to the engine 32 and the exhaust conduit 46 such that exhaust gas from the engine 32 flows into the exhaust manifold 44 and through the exhaust conduit 46. Both the exhaust conduit 46 and the outlet 48 are coupled to the muffler 42, and exhaust gas in the exhaust conduit 46 flows into the muffler 42 and exits the vehicle 2 at the outlet 48. The muffler 42 can be considered a silencer and is configured for sound attenuation within the exhaust assembly 40.

[0096] The powertrain assembly 30 and the exhaust assembly 40 can have various configurations. Illustratively, in the embodiment of FIG. 8B , the engine 32 is positioned longitudinally rearward of the intake assembly 38, and the cylinders 31 of the engine 32 are positioned in a lateral arrangement that is generally perpendicular to the longitudinal axis L. In this configuration of the engine 32, the CVT 34 is positioned laterally outward of the engine 32 and extends generally parallel to the longitudinal axis L. In one embodiment, the CVT 34 is generally positioned rearward of a portion of the driver’s seat of the seat 18 and to the left of the longitudinal axis L. In other embodiments, the intake assembly 38 can be positioned in any location relative to the engine 32 (e.g., above the engine 32, forward of the engine 32, etc.).

[0097] Still referring to FIG. 8B , the exhaust manifold 44 is positioned longitudinally rearward of the cylinders 31 and can be longitudinally intermediate the engine 32 and the muffler 42. The inlet 60 of the muffler 42 can be positioned to the right of the longitudinal axis L, and as such, the exhaust conduit 46 curves or bends toward the right side of the vehicle 2 to couple with the inlet 60 of the muffler 42. The outlet 62 of the muffler 42 can be positioned to the left of the longitudinal axis L. The muffler 42 extends laterally between the inlet 60 and the outlet 62 and intersects the longitudinal axis L.

[0098] Now referring to FIG. 8C and FIG. 8D , the disclosed embodiments generally position the engine 32 rearward of the CVT 34 such that the CVT 34 is longitudinally intermediate the seat 18 and the engine 32. In this configuration, the cylinders 31 of the engine 32 extend along the longitudinal direction, and each cylinder can intersect the longitudinal axis L. FIG. 8C The CVT 34 is disclosed as a steel-belted CVT, while FIG. 8D the CVT 34 is disclosed as a rubber-belted CVT. At least FIG. 8CAdditional details of the steel belt CVT can be found in U.S. patent application Ser. No. 17 / 147,937 (Attorney Docket No. PLR-06-28903.02P-US), filed on Jan. 13, 2021, the entire disclosure of which is expressly incorporated herein by reference. Illustratively, the air intake assembly 38 is positioned laterally outboard of the engine 32, and while shown to the right of the longitudinal axis L, the air intake assembly 38 can also be positioned to the left of the longitudinal axis L. FIG. 8C and FIG. 8D In the embodiment of FIG. 4 , the exhaust manifold 44 extends from the engine 32 to the left of the longitudinal axis L, and the exhaust conduit 46 is generally parallel to the longitudinal axis L as it extends between the exhaust manifold 44 and the muffler 42. As such, the inlet 60 of the muffler 42 may be positioned to the left of the longitudinal axis L, and the outlet 62 of the muffler 42 may be positioned to the right of the longitudinal axis L. The muffler 42 is positioned rearward of the engine 32 such that the engine 32 is longitudinally intermediate the muffler 42 and the CVT 34.

[0099] refer to FIG. 10 , showing in more detail FIG. 8B . Illustratively, the exhaust duct 46 may include a first coupling or joint 64 and a second coupling or joint 66. The exhaust duct 46 includes a first bend 68, a generally linear portion 70, and a second bend 72, however, the exhaust duct 46 may include any configuration relative to the longitudinal axis L, the exhaust manifold 44, and the muffler 42. The configuration of the exhaust duct 46 does not interfere with the rear transmission 37 or any other components supported on the frame assembly 10. FIG. 10 As shown, the exhaust manifold 44 may be positioned generally above a portion of the shiftable transmission 36 and / or the rear transmission 37 .

[0100] refer to FIG. 11 , showing in more detail FIG. 8D Illustratively, the exhaust conduit 46 is generally perpendicular to the longitudinal axis L along a linear portion 74, but does include a curved portion 76 that couples with the inlet 60 of the muffler 42. FIG. 10 The embodiments are different, FIG. 11 The exhaust duct 46 is located to the left of the longitudinal axis L.

[0101] refer to FIG. 12 , an exhaust gas constituent sensor is included on the exhaust assembly 40 to measure oxygen and / or other gases within the exhaust gas flowing through the exhaust assembly 40. Illustratively, the exhaust assembly 40 includes at least one exhaust gas constituent sensor 78 positioned upstream of the muffler 42. Thus, the exhaust gas constituent sensor 78 measures the oxygen concentration and / or composition of the exhaust gas before the gas flows into the muffler 42. FIG. 12As shown, exhaust composition sensor 78 is positioned downstream of couplings 64, 66, and there are no other couplings or joints between exhaust composition sensor 78 and at least a portion of muffler 42, such as catalyst 80. For example, sensor 78 and catalyst 80 can be placed immediately downstream of coupling 64 but upstream of coupling 66, downstream of both couplings 64, 66, within muffler 72, or downstream of muffler 42 (e.g., in outlet or tailpipe 48). In this way, sensor 78 and catalyst 80 can be placed anywhere along the length or position of exhaust assembly 40.

[0102] In embodiments further disclosed herein, catalyst 80 can be positioned within muffler 42 to alter an exhaust composition within the exhaust gas before the gas exits vehicle 2 at outlet 48. When catalyst 80 is positioned within muffler 42, there are no couplings or joints positioned between exhaust composition sensor 78 and catalyst 80. In this way, exhaust composition sensor 78 can be a pre-catalyst exhaust composition sensor. Because joints or couplings can periodically leak, introducing fresh air into exhaust assembly 40, a control system of engine 32 can not be able to correct for such added fresh air and can result in decreased emission performance of catalyst 80 if a joint or coupling is positioned between exhaust composition sensor 78 and catalyst 80. Further, the introduction of fresh air can make the air quantity of the exhaust inconsistent, which will result in inefficient and inconsistent performance of catalyst 80. As such, embodiments disclosed herein do not include joints or couplings (e.g., couplings 64, 66) between any exhaust composition sensor (e.g., exhaust composition sensor 78) and catalyst 80. It can be clear that the illustrative embodiments do not disclose any assembled couplings or joints positioned between catalyst 80 and post-catalyst exhaust composition sensor 78.

[0103] If catalyst 80 is positioned outside of muffler 42, for example along the length of exhaust conduit 46, then exhaust composition sensor 78 is also positioned upstream of catalyst 80, and there are no joints or couplings (e.g., couplings 64, 66) positioned between exhaust composition sensor 78 and catalyst 80 in exhaust conduit 46. FIG. 12 Various examples are shown in which exhaust composition sensor 78 and catalyst 80 can be positioned upstream of muffler 42. To accommodate this configuration of catalyst 80 along the length of exhaust conduit 46, the length of exhaust conduit 46 can be lengthened. In various embodiments, the length of exhaust conduit 46 can extend linearly between exhaust manifold 44 and outlet 48 (e.g., see FIG. 28 ), however, in other embodiments (e.g., see FIG. 30 and FIG. 31The length of the exhaust conduit 46 can be increased by looping the exhaust conduit 46 around portions of the engine 32, the exhaust manifold 44, and / or the muffler 42.

[0104] It can be appreciated that based on the disclosure herein, the flow geometry (e.g., curvature) allows for even distribution of exhaust across the face of the catalyst 80 to maintain performance of the catalyst 80. Additionally, the further the catalyst 80 is moved into the muffler 42, the less sound attenuation remains in the muffler 42 because of the flow straightening / matrix (e.g., honeycomb) configuration of the catalyst 80, sound attenuation does not occur until after the exhaust exits the catalyst 80. Further, at low engine speeds / loads, there can be a reverse flow of ambient air up to the outlet 48 and into the muffler 42, potentially affecting operation of the catalyst 80, and as such, the position of the catalyst 80 relative to the outlet 48 can be optimized.

[0105] As disclosed herein and with reference to FIG. 13 and FIG. 14 the catalyst 80 is positioned between the exhaust manifold 44 and the outlet 48. In various embodiments, the catalyst 80 can be positioned within the muffler 42. The muffler 42 can also include a plurality of cross-pipes 82 configured to attenuate sound. Illustratively, the cross-pipes 82 include at least a first cross-pipe 82a, a second cross-pipe 82b, and a third cross-pipe 82c, however, any number of cross-pipes 82 can be included. In one embodiment, the third cross-pipe 82c can be integrally formed with the outlet 48. The muffler 42 can include walls, such as baffles or support walls, configured to support the cross-pipes 82 and further attenuate sound within the muffler 42.

[0106] Exhaust can flow in the direction of arrow F such that the exhaust flows through the exhaust conduit 46 into the muffler 42 and into the catalyst 80. The exhaust follows arrow F from the catalyst 80 and flows to the first cross-pipe 82a. The exhaust flows from the first cross-pipe 82a into the second cross-pipe 82b and traverses a length of the muffler 42 before flowing into the third cross-pipe 82c. The exhaust within the third cross-pipe 82c flows out of the muffler 42 through the outlet 48 to exit the vehicle 2. This flow path, as well as the use of the cross-pipes 82, provides sound attenuation within the muffler 42. The exhaust flowing between the cross-pipes 82 can have a partially turbulent flow, however, the exhaust has an overall laminar or smooth flow as the exhaust flows from the muffler 42 through the third cross-pipe 82c and through the outlet 48.

[0107] Still referring to FIG. 13 and FIG. 14, the exhaust assembly 40 can include a second exhaust constituent sensor 86 positioned downstream of the catalyst 80 such that the second exhaust constituent sensor 86 is a post-catalyst sensor. The second exhaust constituent sensor 86 is supported on the muffler 42 and can be positioned inside or outside of the muffler 42. Illustratively, the second exhaust constituent sensor 86 is positioned outside of the muffler 42 and is in fluid communication with the outlet 48 to measure exhaust constituent levels within the exhaust gas exiting the catalyst 80. As noted herein, the exhaust gas flowing through the outlet 48 and thus over the second exhaust constituent sensor 86 can have more laminar flow relative to the exhaust gas upstream of the catalyst 80. If the exhaust gas has turbulent flow at the second exhaust constituent sensor 86, the measurements of the exhaust constituent sensor 86 can not be accurate. It can be appreciated that the sensor 86 can be used in addition to or in place of the sensor 78, and that any exhaust constituent sensor (alone or in combination with other sensors) can be positioned at any location along the length of the exhaust assembly 40 (e.g., upstream of the catalyst 80, upstream of the muffler 42, downstream of the muffler 42, within the outlet 48, etc.).

[0108] Referring now to FIG. 15 , the exhaust assembly 40 can include a second post-catalyst exhaust constituent sensor, shown as sensor 88. The exhaust constituent sensor 88 is positioned within the muffler 42 and can be positioned generally along the flow path (arrow F) between the second cross-pipe 82b and the third cross-pipe 82c. The exhaust constituent sensor 88 can be used in addition to or in place of the pre-catalyst exhaust constituent sensor 78 and / or the second / post-catalyst exhaust constituent sensor 86. The exhaust constituent sensor 88 provides further measurements of the exhaust gas to enhance control over engine performance and other factors in an effort to reduce emissions from the outlet 48. In other embodiments, the sensor 88 can be positioned near the wall 84 and upstream of the flow through the cross-pipe 82a.

[0109] Referring to FIG. 16 and FIG. 17 , an alternative embodiment muffler 42' is disclosed. The muffler 42' is fluidly coupled with the exhaust conduit 46 and the outlet 48. The exhaust constituent sensors 78, 86 are fluidly coupled to the muffler 42'. The muffler 42' includes the catalyst 80, an alternative embodiment cross-pipe 82', and an alternative embodiment wall(s) 84'. The exhaust gas is configured to flow into, through, and out of the muffler 42' in the direction of arrow F.

[0110] The illustrative muffler 42' includes a first pass-through baffle 90 and a second pass-through baffle 92 positioned adjacent respective housing walls 94 and 96. The at least second exhaust gas constituent sensor 86 can be supported on the muffler 42' by a weld boss 98 (e.g., a plug weld). The weld boss 98 can be positioned generally parallel to an axis 99 of the catalyst 80 (e.g., within a range of about 0 degrees to about 15 degrees relative to the axis 99). The exhaust gas constituent sensor 86 can extend through a portion of the pass-through baffle 92 and the housing wall 96. Illustratively, the baffle 92 and the wall 96 can be coupled together and form a chamber of the muffler 42' such that the sensor 86 extends through the chamber defined by the baffle 92 and the wall 96. Further, the curved or arcuate baffle 92 and wall 96 direct exhaust gas flow across the sensor 86 to provide an increased flow distribution across the sensor 86. In this manner, the exhaust gas constituent sensor 86 utilizes the wall 96 and can collect measurements from within the inner chamber of the muffler 42'. The pass-through baffle 92 is formed to protrude inside and outside of the wall 96. The exhaust gas constituent sensor 86 is able to monitor post-catalyst exhaust gas from within the muffler 42' and / or a portion of the wall 96, and more particularly, can monitor exhaust gas from within the inner chamber of the muffler 42'.

[0111] Reference is now made to FIGS. 18-31 In order to improve emissions from the outlet 48, the temperature of the exhaust assembly 40 is reduced. By reducing the temperature of the exhaust assembly 40, extended stoichiometric engine operation is available, which allows for proper catalyst operation. The cooling of the exhaust assembly 40 also reduces the severity of the exhaust assembly 40 as a source of radiant heat during hot soak conditions, such as immediately after heavy load operation of the vehicle engine 32 is shut off. Various embodiments disclosed herein can be configured to limit the temperature of at least a portion of the exhaust assembly 40 and / or the exhaust gas to a temperature limit (e.g., 800-1000 °C) to reduce or prevent damage to the catalyst 80. The temperature limit can be based on an exhaust gas temperature value or limit relative to other portions of the exhaust assembly 40, such as a thermal degradation temperature range of respective components of the exhaust assembly 40.

[0112] Conventional methods of reducing the temperature of the exhaust assembly 40 and preventing thermal damage to the engine 32 and exhaust components can include fuel enrichment. More specifically, fuel enrichment can be used to reduce exhaust gas temperature through evaporative cooling. However, when the engine 32 is operated with fuel enrichment, catalyst emissions can increase, and thus, catalyst performance can decrease and emissions at the outlet 48 can increase. As disclosed herein with respect to FIGS. 18-31 Fuel enrichment is avoided if exhaust gas cooling can be provided by alternative methods.

[0113] In FIG. 18In the embodiment of FIG. 1 , vehicle bypass air (i.e., air flowing over and around vehicle 2 ), as indicated by arrows A, can be used to cool exhaust assembly 40 . By redirecting vehicle bypass air A across exhaust assembly 40 , convective heat removal from exhaust assembly 40 is increased, thereby reducing exhaust gas temperature. The bypass air can be redirected through a portion of vehicle 2 by portions of vehicle body 20 (such as a body panel (schematically shown at 95 ) configured as a deflector and / or duct) and / or portions of frame assembly 10 , which can also be configured as deflectors 95 . Ducts or deflectors 95 can be positioned anywhere along the longitudinal length of vehicle 2 . As disclosed herein, by reducing exhaust gas temperature, stoichiometric engine operation can occur at higher engine speeds and loads while reducing emissions from vehicle 2 , which allows for proper catalyst operation, thereby reducing emissions at outlet 48 . The rate of vehicle bypass air A increases with increasing engine speed and load, and thus, enhanced cooling of exhaust assembly 40 occurs when cooling is most needed.

[0114] exist FIG. 19 In the embodiment of the present invention, convective cooling is provided to the exhaust assembly 40 by airflow (arrow 104) that has passed through the radiator 100 of the vehicle 2. In one embodiment, the radiator 100 is the primary radiator of the engine 32; however, in other embodiments, the radiator 100 may be a secondary radiator disposed within the primary cooling assembly of the engine 32. The radiator 100 may include a conduit 102 fluidly coupled to the engine 32 for flowing coolant to and receiving coolant from the engine 32. Cooling of the exhaust assembly 40 is provided by airflow that has passed through the radiator 100 and is redirected toward the exhaust assembly 40 due to the vehicle ram effect or by using an electric fan for the radiator 100 (positioned near the radiator 100). In this manner, convective heat removal from the exhaust assembly 40 reduces exhaust gas temperature. In the case of radiator airflow caused by the vehicle ram effect, airflow naturally increases as engine speed / load increases due to increasing vehicle speed, thereby enhancing exhaust gas cooling when cooling is most needed.

[0115] exist FIG. 20In an embodiment, convection cooling is provided to the exhaust assembly 40 by airflow (arrow 106) from a fan 108. The fan 108 can be an electronically controlled fan. Using the fan 108 to provide airflow across the exhaust assembly 40 provides a convection heat removal enhancement from the exhaust assembly 40 to reduce the exhaust gas temperature. The fan 108 can be controlled by an engine control unit or module (not shown) and can be operated only under elevated engine speed / load conditions when it is desired to enhance the cooling of the exhaust assembly 40 and when additional electrical load capacity can be obtained from the charging system (not shown). The fan 108 can also be used during low vehicle speed conditions, when the vehicle 2 is stationary, and / or when the engine 32 is turned off to extract heat from the exhaust assembly 40. In one embodiment, the fan 108 can be positioned near the hottest section of the exhaust assembly 40.

[0116] exist FIG. 21 In the embodiment of the present invention, convective cooling is provided to the exhaust assembly 40 by airflow (arrow 110) from the exhaust / outlet port 58 of the CVT 34. For example, the opening of the outlet port 58 can be oriented to directly flow the outlet air from the CVT 34 onto a portion of the exhaust assembly 40. Additionally or alternatively, a duct, deflector, or other similar mechanism can be used to further direct the CVT exhaust gas onto the exhaust assembly 40. By redirecting the airflow exiting the CVT 34 across a portion of the exhaust assembly 40, enhanced convective heat removal from the exhaust assembly 40 occurs to reduce the exhaust gas temperature of the exhaust assembly. As the clutch speed (e.g., the speed of the first pulley and / or the second pulley of the CVT 34) increases, the airflow from the CVT 34 can naturally increase as the engine speed / load increases, thereby providing enhanced exhaust system cooling when enhanced cooling is desired.

[0117] exist FIG. 22 In an embodiment, convective cooling is provided to the exhaust assembly 40 by airflow (arrow 112) from a cooler 114. In one embodiment, the cooler 114 may be a transmission cooler for the shiftable transmission 36. By redirecting the airflow that has passed through the cooler 114 across the exhaust assembly 40, whether the airflow is due to the vehicle speed ram effect or caused by a fan (not shown) (e.g., an electric fan), convective heat removal from the exhaust assembly 40 is enhanced to reduce the exhaust gas temperature. The cooler 114 may be supported at the rear portion 118 ( FIG. 23 ) and is positioned so that air exiting the cooler 114 flows directly across a portion of the exhaust assembly 40. When airflow to the cooler 114 is caused by the vehicle speed ram effect, the airflow can naturally increase as engine speed / load increases due to increased vehicle speed and, therefore, provide enhanced cooling of the exhaust assembly 40 when enhanced cooling is desired. The cooler 114 can be an air / liquid cooler, or a liquid / liquid cooler.

[0118] In FIG. 23 embodiments, convective cooling is provided to the exhaust assembly 40 by airflow (arrow 119) through the wheel well 116 of the rear ground contact member 8 at the rear portion 118 of the undercarriage assembly 12. More specifically, the turbulent air present in the wheel well 116 is redirected to flow over a portion of the exhaust assembly 40. By redirecting this turbulent airflow in the wheel well 116 across the exhaust assembly 40, convective heat rejection is enhanced from the exhaust assembly 40 to reduce exhaust gas temperatures. As the rotation of the rear ground contact member 8 increases, the turbulent airflow through the wheel well 116 naturally increases as engine speed / load increases, thereby providing cooling to the exhaust assembly 40 when it is most needed. The air at the wheel well 116 can be directed toward the exhaust assembly 40 by a portion of the vehicle body 20 and / or a portion of the frame assembly 10 that is configured as a deflector, duct, or other mechanism to direct air inward toward the exhaust assembly 40.

[0119] In FIG. 24 embodiments, convective cooling is provided to the exhaust assembly 40 by using a closely coupled catalyst or pre-catalyst 122 to enhance convective heat rejection from the exhaust assembly 40 and reduce the exotherm experienced in the catalyst 80 downstream of the catalyst 122. More specifically, the catalyst 122 is positioned upstream of the catalyst 80 and can be located intermediate the exhaust manifold 44 and the catalyst 80 in position. As such, the catalyst 122 can be supported on the exhaust conduit 46 or can be positioned upstream of the catalyst 80 within the muffler 42.

[0120] The catalyst 122 generates an exotherm that increases exhaust gas temperatures at the front section of the flow path 120 through the exhaust assembly 40, thereby increasing the AT component of the heat rejection. AT defines the temperature difference between the hot exhaust gas and the cooling fluid or medium (e.g., ambient air). The heat transfer rate (Q) can be expressed as Q = m * Cp * dT, where m = mass flow rate of the cooling fluid (e.g., air flowing across the exhaust assembly 40), Cp = heat capacity of the cooling fluid (e.g., water has a higher heat capacity than air, thus water is more effective for cooling), and dT = difference between the temperature difference of the cooled surface (exhaust system surface) and the temperature of the cooling fluid.

[0121] It can be appreciated that the catalyst 122 is generally positioned in proximity to the engine 32 and the exhaust manifold 44 such that the exotherm occurring in the catalyst occurs early in the exhaust assembly 40. However, as FIG. 24As shown, the catalyst 122 also helps to enhance heat transfer from the exhaust assembly 40 upstream of the catalyst 80 when positioned along any length of the exhaust conduit 46. In various embodiments, the catalyst 122 can be positioned with the catalyst 80 in the muffler 42 such that the catalysts 122, 80 are positioned in series within the muffler 42, or the catalyst 80 can be a multi-chamber catalyst that includes multiple catalyst portions in series with one another within the muffler 42.

[0122] Additionally, as the exhaust gas continues to flow through the downstream portion of the exhaust assembly 40, the catalyst 122 can partially clean the exhaust gas to reduce emissions from the exhaust gas. This partial cleaning of the exhaust gas results in a reduced heat release in the catalyst 80, and thus, the catalyst 80 does not experience as much heat during operation of the exhaust assembly 40. The catalyst 122 can be configured to only partially clean the exhaust gas such that the catalyst 122 does not experience full or complete heat release. The catalyst 122 can have a honeycomb configuration with a lower cell density than the cell density of the catalyst 80. Further, the catalyst 122 can have an equal or reduced size as the catalyst 80, and a large diameter-to-length ratio such that it is less likely to create exhaust flow restrictions. It can be appreciated that the catalyst 122 not only reduces the temperature experienced by the exhaust assembly 40, but also reduces emissions more quickly after the engine 32 begins operation (e.g., as compared to an exhaust system without the catalyst 122) because it reaches an appropriate operating temperature more quickly, provided it is closer to the engine 32.

[0123] In FIG. 25 embodiments, cooling is provided to the exhaust assembly 40 by utilizing a water jacket or cooling jacket 124 around a portion of the exhaust assembly 40 to enhance heat extraction from the exhaust gas at a front section of the flow path (e.g., before the catalyst 80). The cooling jacket 124 includes at least one channel 126 configured to receive cold water or other coolant / fluid (e.g., glycol) to reduce the temperature of a portion of the exhaust assembly 40 (e.g., a portion of the exhaust conduit 46 upstream of the catalyst 80). Providing the cooling jacket 124 around a portion of the exhaust conduit 46 enhances heat extraction from the exhaust gas. However, the cooling jacket 124 can provide too much exhaust heat for the cooling assembly of the engine 32 to manage, and as such, additional cooling circuits can be needed to best manage the cooling of the exhaust assembly 40 and the cooling of the engine 32. Using separate circuits can allow for optimization of the cooling for coolant flow rate, temperature thresholds, etc., such that the cooling jacket 124 only extracts a target amount of heat and / or is only used during elevated engine speed / load conditions when enhanced cooling is desired.

[0124] In FIG. 26In embodiments, cooling is provided to the exhaust assembly 40 by a cooling jacket 128 around a portion of the exhaust assembly 40 to enhance heat rejection from the exhaust gas at an upstream section of the flow path (e.g., upstream and / or proximate to the exhaust manifold 44). The cooling jacket 128 includes at least one passage 129 configured to circulate cold water or other coolant / fluid to reduce the temperature of a portion of the exhaust assembly 40 (e.g., a portion of the exhaust manifold 44 proximate to the engine 32). The cooling jacket 128 can be integrated into the exhaust manifold 44 or can be separate from the exhaust manifold and, for example, can define an extension of the exhaust ports of the engine 32. It can be appreciated that the exhaust manifold 44 is coupled to the exhaust port(s) of the engine 32. The exhaust ports of the engine 32 are typically flush with the cylinder block of the cylinder 31, however, in FIG. 26 In embodiments, cooling is provided to the exhaust assembly 40 by a cooling jacket 130 around a portion of the exhaust assembly 40 to enhance heat rejection from the exhaust gas at an upstream section of the flow path. The cooling jacket 130 includes at least one passage 132 configured to receive cold water or other coolant / fluid to reduce the temperature of a portion of the exhaust assembly 40 (e.g., a portion of the exhaust conduit 46). The cooling jacket 130 is fluidly coupled to a cooling circuit 134 that includes a heater 136 for the vehicle 2. More specifically, the heater 136 can be used to heat the cab of the vehicle 2 (e.g., when the operator area 16 is enclosed) by receiving heat rejected from the exhaust assembly 40 by water / fluid that is heated after cooling the exhaust conduit 46.

[0125] In FIG. 27 In embodiments, cooling is provided to the exhaust assembly 40 by a cooling jacket 130 around a portion of the exhaust assembly 40 to enhance heat rejection from the exhaust gas at an upstream section of the flow path. The cooling jacket 130 includes at least one passage 132 configured to receive cold water or other coolant / fluid to reduce the temperature of a portion of the exhaust assembly 40 (e.g., a portion of the exhaust conduit 46). The cooling jacket 130 is fluidly coupled to a cooling circuit 134 that includes a heater 136 for the vehicle 2. More specifically, the heater 136 can be used to heat the cab of the vehicle 2 (e.g., when the operator area 16 is enclosed) by receiving heat rejected from the exhaust assembly 40 by water / fluid that is heated after cooling the exhaust conduit 46.

[0126] Using the cooling jacket 130 can produce too much heat rejection for the cooling components of the engine 32 (e.g., the radiator 100, 138) to manage, thus the cooling circuit 134 can be used. Using a separate circuit 134 allows for optimization of cooling for coolant flow rate, temperature thresholds, etc., such that only a target amount of heat is extracted from the exhaust assembly 40 and / or only during elevated engine speeds / loads when cooling is most needed. The cooling circuit 134 can be used as a heat source for the heater 136, rather than having the heater 136 rely on the cooling components of the engine 32 to provide heat to the operator area. The cooling circuit 134 can improve heating of the operator area 16 at low engine speeds / loads, reduce the time to heat after the engine 32 is started, or both, compared to a cab heating system that only uses the cooling components of the engine 32.

[0127] With respect to embodiments of the FIGS. 25-27 , the cooling components of the engine can include a secondary radiator, or other heat exchanger 138 (in combination with or in place of the radiator 100 of the FIG. 19 ) can be provided that is fluidly coupled with the water jackets 124, 128, 130. The secondary radiator 138 can be used because the primary radiator for the engine 32 can not provide sufficient cooling for the cooling fluid flowing through the water jackets 124, 128, 130. The secondary radiator 138 can be positioned anywhere on the vehicle 2. For example, the secondary radiator 138 can be positioned in a front portion of the vehicle 2 to be subjected to undisturbed cool ambient air. It can be appreciated that the water jackets 124, 128, 130 can be used individually or in any combination with each other.

[0128] In embodiments of the FIGS. 28-31 , the length of the exhaust assembly 40 (e.g., the exhaust conduit 46) can be lengthened upstream of the catalyst 80 to enhance heat rejection from the exhaust gas before the exhaust gas enters the catalyst 80. Lengthening the length of the exhaust conduit 46 enhances convective heat rejection from the exhaust assembly 40 by allowing more heat transfer time and surface area. In some examples, lengthening the length of the exhaust conduit 46 can also enable exhaust regulation, which can help develop a torque curve.

[0129] As best shown in FIGS. 29-31 , the length of the exhaust conduit 46 can be increased in a variety of configurations, and illustratively, the length of the exhaust conduit 46 is increased by wrapping the exhaust conduit 46 around various components of the powertrain assembly 30 and / or the exhaust assembly 40. More specifically, due to the compact arrangement of the vehicle 2 and the number of components supported adjacent to the engine 32 on the lower frame assembly 12, it can be necessary to lengthen the length of the exhaust conduit 46 at locations proximate the engine 32 to prevent interference with other components.

[0130] Illustratively, as FIG. 30shown and with FIG. 29 Compared to the length of the exhaust duct 46 shown, the length of the exhaust duct 46 can be extended by wrapping the exhaust duct 46 around the engine 32 and the muffler 42 so that the exhaust duct 46 is longitudinally positioned intermediate the engine 32 and the muffler 42. In this manner, the exhaust duct 46 can begin at the exhaust manifold 44 on a first side of the longitudinal axis L and end at the muffler 42 along a second side of the longitudinal axis L. Additionally, as shown in FIG. FIG. 31 As shown, the length of the exhaust duct 46 can be extended by wrapping the exhaust duct 46 around the muffler 42 so that the catalyst 80 is positioned longitudinally intermediate the engine 32 and the exhaust duct 46. In this manner, the exhaust duct 46 can begin at the exhaust manifold 44 on a first side of the longitudinal axis L and end at the catalyst 80 along a second side of the longitudinal axis L. FIG. 30 and FIG. 31 The embodiment extends the length of the exhaust conduit 46 to improve heat removal from the exhaust component 40 upstream of the catalyst 80 .

[0131] exist FIGS. 32-35 In the embodiment of FIG. 5 , cooling is provided to the exhaust assembly 40 by a fan 150 mounted to an alternator 152 of the engine 32. The alternator 152 is operably coupled to the engine 32, and the fan 150 is removably coupled to the alternator 152 by fasteners 154 ( FIG. 34 ). The fan 150 may be protected by a cover 156. In operation, as air flows through the vehicle 2 in a rearward direction (as indicated by arrow 158), the air flows over the engine 32 and through the fan 150, which directs the air rearward toward the exhaust assembly 40. More specifically, air flowing to the rear of the vehicle 2 is drawn from under the intake manifold of the engine 32, across the alternator 152, through the fan 150 and directed at portions of the exhaust assembly 40 such as the vibration isolators (e.g., isolator 160) and the pre-catalyst exhaust gas constituents sensor 78. In this manner, the airflow at the exhaust assembly 40 provides cooling by convection and allows the heated air to exit the vehicle 2 at the rear of the vehicle. This airflow also benefits the alternator 152 because heat is removed from the alternator 152 as the air flows rearward in the vehicle 2. Although FIGS. 32-35 An alternator 152 is included, but it will be appreciated that the same cooling effect of the exhaust assembly 40 may be achieved by other components of the vehicle 2 , such as any belt-driven components of the powertrain assembly 30 .

[0132] about FIGS. 18-35 any embodiment, fin or other feature (in FIG. 26An exhaust conduit 46 can be provided on the exhaust manifold 44 to increase the surface area thereof (shown schematically as 140). By increasing the surface area of the exhaust conduit 46, heat transfer from the exhaust assembly 40 upstream of the catalyst 80 can be improved.

[0133] It can be appreciated that any of the cooling embodiments of FIGS. 18-35 may be used alone or in combination with any other cooling embodiment depending on the configuration and parameters of the vehicle 2, powertrain assembly 30, and exhaust assembly 40. Further, in embodiments of FIGS. 18-35 it can be clear that minimal thermal shielding and / or shielding is exhibited along the length of the exhaust conduit 46 to allow for increased heat transfer out of the exhaust conduit 46 prior to reaching the catalyst 80. Further, with any of the embodiments disclosed herein, it can be desirable to increase the flow rate of the cooling fluid or medium (e.g., air, water, coolant, etc.) to enhance heat transfer from the exhaust assembly 40. The cooling medium can be provided at any location along the length of the exhaust assembly 40 upstream of the catalyst 80. In this manner, the disclosure herein FIGS. 18-35 combines the disclosure of minimal thermal shielding / shielding and methods for increasing the flow rate of the cooling medium to improve cooling of the exhaust assembly 40, which can enhance catalyst operation at elevated engine speeds / loads, thereby reducing emissions at the outlet 48. More specifically, and from the disclosure of FIGS. 18-35 it can be clear that the exhaust temperature is affected by thermal shielding, airflow, exhaust conduit length, calibration parameters, and other factors from any of the embodiments of FIGS. 18-35 alone or in combination.

[0134] Referring now to FIG. 36 and FIG. 37 an alternative configuration of the exhaust conduit 46 is shown as conduit 46'. The exhaust conduit 46' includes a first conduit portion 170 fluidly coupled to the exhaust manifold 44 and a second conduit portion 172 fluidly coupled to the muffler 42. A flexible bellows element 174 also defines a portion of the exhaust conduit 46' and is illustratively positioned intermediate the first conduit portion 170 and the second conduit portion 172 such that the bellows element 174 is downstream of the first conduit portion 170 and the engine 32 but upstream of the second conduit portion 172, the muffler 42, and the exhaust constituent sensors 78, 86. In one embodiment, the bellows element 174 can be welded to the first conduit portion 170 and / or the second conduit portion 172; however, as FIG. 37As shown, the bellows element 174 can be removably coupled to the at least second conduit portion 172 by a removable coupler such as a clamp 176. The bellows element 174 enables flexibility along the flow path of the exhaust gas while also maintaining the flow of the exhaust gas. More specifically, due to the positioning and configuration of the bellows element, the bellows element 174 is configured to flex or move in lieu of forward / backward translational forces with movement of the engine 32. In one embodiment, the bellows element 174 is constructed of multiple layers such as interlocking metal layers, a thin metal bellows layer, and an outer braided material that allow the bellows element 174 to compress and move with movement of the engine 32.

[0135] As shown, FIG. 36 the bellows element 174 is positioned longitudinally rearward of the engine 32 and longitudinally forward of the muffler 42. Because the engine 32 can be positioned rearward of the seat 18 in various embodiments, the bellows element 174 can also be positioned rearward of the seat 18. Depending on the orientation of the engine 32 within the vehicle 2, the crankshaft axis CSA can extend in a generally longitudinal direction of the vehicle 2, while a flow axis of the bellows element 174 (shown as BEA) can be generally perpendicular to the crankshaft axis CSA. More specifically, the bellows element axis BEA can be positioned at approximately 87-93 degrees to the crankshaft axis CSA. In various embodiments, the bellows element 174 is positioned within a lateral width of the engine 32 and / or the muffler 42 and can be centered along the lateral width of the muffler 42 and / or the engine 32.

[0136] Referring now to FIGS. 38-40 , the inlet pipe 180 of the muffler 42 (which can generally be defined as a portion of the exhaust conduit 46, 46' and can include the first conduit portion 170 and the second conduit portion 172 FIG. 36 and FIG. 37 ) and the outlet pipe 48 can be offset or angled from a centerline of the muffler 42 and not in a plane. Offsetting the inlet pipe 180 and / or the outlet pipe 48 from the muffler 42 allows for tighter packaging of components adjacent to the muffler 42. In this manner, the packaging of the exhaust assembly 40 enables available space for other components of the vehicle 2. In one embodiment, an inlet axis IA of the inlet pipe 180 can be at an angle of less than 90 degrees to a muffler width or lateral axis MWA, which allows for tighter packaging as the inlet pipe 180 enters the muffler 42. At least as shown, FIGS. 13-15 the cross pipe 82 can be parallel to the muffler width axis MWA, such that the inlet pipe 180 is also at an angle of less than 90 degrees to an axis of the cross pipe 82. As shown, FIG. 40As shown, the inlet axis IA can be angled relative to the muffler longitudinal axis MLA. Further, the inlet axis IA is angled relative to a vertical axis V of the muffler 42, and in one embodiment, is angled at 45 degrees or less relative to the vertical axis V.

[0137] Still referring to FIGS. 38-40 , the outlet axis OA of the outlet pipe 48 is also angled relative to the vertical axis V, and in one embodiment, is angled at approximately 25-65 degrees relative to the vertical axis V. Additionally, the outlet axis OA is angled at less than 90 degrees relative to the muffler longitudinal axis MLA and at less than 90 degrees relative to the muffler width axis MWA.

[0138] As FIGS. 41-43 shown, the muffler 42 can include a heat shield 162 positioned proximate the exhaust gas composition sensor 86. The exhaust gas composition sensor 86 is a post-catalyst sensor and is generally positioned proximate the outlet pipe 48. As such, in one embodiment, the heat shield 162 can be positioned generally adjacent the outlet pipe 48. Illustratively, the heat shield 162 is coupled to a wall (e.g., wall 96 FIG. 16 ) of the muffler 42, however, the heat shield 162 can be coupled at least partially to a portion of the sensor 86, can be coupled to a portion of the chassis of the vehicle 2, or can be coupled to any other component of the vehicle 2 at a location that protects the sensor 86 from radiant heat. Illustratively, the heat shield 162 is mounted to the muffler 42, and at least a portion of the heat shield 162 is spaced apart from the muffler 42 by an offset distance or air gap 164. The air gap 164 can have a distance of approximately 1 to 7 mm. The air gap 164 can be defined by a tab 166 of the heat shield 162 that extends from a central body 168 of the heat shield 162. The tab 166 is angled relative to the central body 168 and contacts the muffler 42 such that the central body 168 is held at the offset distance of the air gap 164 relative to the tab 166 and the muffler 42. During operation of the exhaust assembly 40, the heat shield 162 and the air gap 164 protect the sensor 86 from heat that is radiated from the muffler 42 and would otherwise be directed toward the sensor 86.

[0139] Additional details of the vehicle 2 and / or powertrain components can be disclosed in U.S. Patent Application Serial No. 15 / 388,436 (Attorney Docket No. PLR-15-27200.00P), filed December 22, 2016; U.S. Patent Application Serial No. 15 / 388,106 (Attorney Docket No. PLR-06-27992.00P), filed December 22, 2016; and U.S. Patent Application Serial No. 16 / 238,991 (Attorney Docket No. PLR-15-28340.04P), filed January 3, 2019, the entire disclosures of which are hereby expressly incorporated by reference herein.

[0140] The following clauses recite example subject matter that describes innovations described herein.

[0141] Clause 1. A utility vehicle, comprising: a frame assembly extending along a longitudinal axis and defining an operator area; a plurality of ground-engaging members supporting the frame assembly and including front and rear ground-engaging members; a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine; and an exhaust assembly including: an exhaust conduit fluidly coupled to the engine; a catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit; and a cooling mechanism configured to provide cooling fluid to a portion of the exhaust assembly.

[0142] Clause 2. The utility vehicle of clause 1, wherein the cooling mechanism defines a deflection mechanism configured to direct bypass air through a portion of the utility vehicle and toward the exhaust assembly.

[0143] Clause 3. The utility vehicle of clause 1, wherein the cooling mechanism defines a radiator configured to provide cooling fluid to the engine.

[0144] Clause 4. The utility vehicle of clause 1, wherein the cooling mechanism defines a fan.

[0145] Clause 5. The utility vehicle of clause 1, wherein the cooling mechanism defines an outlet port of the transmission.

[0146] Clause 6. The utility vehicle of clause 1, wherein the cooling mechanism defines a cooler configured to provide cooling fluid to the transmission.

[0147] Clause 7. The utility vehicle of clause 1, wherein the cooling mechanism defines a deflection mechanism positioned at a wheel well of the rear ground-engaging members.

[0148] Clause 8. The utility vehicle of clause 1, wherein the cooling mechanism defines a water jacket.

[0149] Clause 9. The utility vehicle of clause 8, wherein the water jacket is positioned along a portion of the exhaust conduit.

[0150] Clause 10. The utility vehicle of clause 8, wherein the water jacket is fluidly coupled to a cooling circuit, and the cooling circuit includes a heater for the operator area.

[0151] Clause 11. The utility vehicle of clause 10, wherein the cooling circuit defines a first cooling circuit, and a second cooling circuit is operably coupled to the engine and separate from the first cooling circuit.

[0152] Clause 12. The utility vehicle of clause 10, wherein the exhaust assembly further includes an exhaust manifold fluidly coupled to the engine and the exhaust conduit, and the water jacket is positioned along a portion of the exhaust manifold.

[0153] Clause 13. A method of cooling a portion of an exhaust assembly for an engine of a utility vehicle, the method comprising: providing an exhaust conduit; fluidly coupling a catalyst to the exhaust conduit; directing a fluid at a portion of the exhaust assembly; and reducing a temperature of exhaust gas flowing through the exhaust assembly after the fluid is directed at the portion of the exhaust assembly.

[0154] Clause 14. The method of clause 13, wherein directing the fluid includes directing bypass air through a portion of the utility vehicle and toward the portion of the exhaust assembly.

[0155] Clause 15. The method of clause 13, wherein directing the fluid includes directing air through a radiator fluidly coupled to the engine and toward the portion of the exhaust assembly.

[0156] Clause 16. The method of clause 13, wherein directing the fluid includes directing air through a fan and toward the portion of the exhaust assembly.

[0157] Clause 17. The method of clause 13, further comprising providing a transmission operably coupled to the engine, and wherein directing the fluid includes expelling air from the transmission and directing the air toward the portion of the exhaust assembly.

[0158] Clause 18. The method of clause 13, wherein directing the fluid includes flowing the fluid through a water jacket positioned at the portion of the exhaust assembly.

[0159] Clause 19. The method of clause 18, further comprising positioning the water jacket along a portion of the exhaust conduit.

[0160] Clause 20. The method of clause 18, further comprising providing an exhaust manifold fluidly coupled with the engine and the exhaust conduit and positioning the water jacket along a portion of the exhaust manifold.

[0161] Clause 21. A utility vehicle, comprising: a frame assembly extending along a longitudinal axis and defining an operator area; a plurality of ground engaging members supporting the frame assembly and including a front ground engaging member and a rear ground engaging member; a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine; and an exhaust assembly including: an exhaust conduit fluidly coupled to the engine; a first catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit; and a second catalyst positioned along the exhaust conduit downstream of the first catalyst.

[0162] Clause 22. The utility vehicle of clause 21, wherein the second catalyst is positioned within a muffler of the exhaust assembly.

[0163] Clause 23. The utility vehicle of clause 21, wherein the first catalyst is equal to or smaller in size than the second catalyst.

[0164] Clause 24. A utility vehicle, comprising: a frame assembly extending along a longitudinal axis and defining an operator area; a plurality of ground engaging members supporting the frame assembly and including a front ground engaging member and a rear ground engaging member; a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine; and an exhaust assembly including: an exhaust conduit fluidly coupled to the engine; and a catalyst fluidly coupled to exhaust conduit and configured to receive exhaust gas from the exhaust conduit, and the exhaust conduit, the engine, and the catalyst are positioned adjacent to one another along the longitudinal axis.

[0165] Clause 25. The utility vehicle of clause 24, wherein the exhaust conduit is positioned longitudinally intermediate the engine and the catalyst.

[0166] Clause 26. The utility vehicle of clause 24, wherein the catalyst is positioned longitudinally intermediate the engine and the exhaust conduit.

[0167] Clause 27. The utility vehicle of clause 24, wherein the exhaust assembly further includes an exhaust composition sensor supported by the exhaust conduit, and the exhaust gas is continuous between the exhaust sensor and the catalytic converter.

[0168] Clause 28. The utility vehicle of clause 27, wherein the sensor is positioned downstream of the catalytic converter.

[0169] Clause 29. The utility vehicle of clause 28, wherein the exhaust assembly further includes a heat shield positioned adjacent the sensor.

[0170] Clause 30. The utility vehicle of clause 29, wherein at least a portion of the heat shield is spaced apart from the muffler by an air gap.

[0171] Clause 31. The utility vehicle of clause 27, wherein the exhaust assembly further includes a muffler, and the exhaust conduit includes a bellows, and the bellows is positioned within the utility vehicle longitudinally intermediate the muffler and the engine.

[0172] While this application has been described as having exemplary designs, the present application can be further modified within the spirit and scope of the disclosure. This application is therefore intended to cover any variations in the application that would be apparent to those of ordinary skill in the art upon reading the description herein. Further, this application includes all products made using any of the processes of the application.

Claims

1. A multi-purpose vehicle comprising: a frame assembly extending along a longitudinal axis and defining an operator area; a plurality of ground contact members supporting the frame assembly and including front and rear ground contact members; at least one wheel well supported by the rear contact member; a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine, wherein the engine is located longitudinally rearward of the operator area; as well as An exhaust assembly, the exhaust assembly comprising: an exhaust conduit fluidly coupled to the engine; a catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit; and a cooling mechanism configured to provide cooling fluid to a portion of the exhaust assembly, wherein the cooling mechanism includes a deflection mechanism positioned at at least one wheel well of the rear contact member to direct air from the at least one wheel well toward the portion of the exhaust assembly, wherein a rate of cooling air directed toward the portion of the exhaust assembly increases as a speed of the utility vehicle increases.

2. The utility vehicle of claim 1, wherein: The cooling mechanism also includes a radiator configured to provide the cooling fluid to the engine.

3. The utility vehicle of claim 1, wherein: The cooling mechanism also includes a fan.

4. The utility vehicle of claim 1, wherein: The cooling mechanism also includes an outlet port of the transmission.

5. The utility vehicle of claim 1, wherein: The cooling mechanism also includes a cooler configured to provide cooling fluid to the transmission.

6. The utility vehicle of claim 1, wherein: The cooling mechanism also includes a cooling jacket.

7. The utility vehicle of claim 6, wherein: The cooling jacket is positioned along a portion of the exhaust duct.

8. The utility vehicle of claim 6, wherein: The cooling jacket is fluidly coupled to a cooling circuit, and the cooling circuit includes a heater for the operator area.

9. The utility vehicle of claim 8, wherein: The cooling circuit includes a first cooling circuit, and a second cooling circuit is operably coupled to the engine and is distinct from the first cooling circuit.

10. The utility vehicle of claim 8, wherein: The exhaust assembly further includes an exhaust manifold fluidly coupled with the engine and the exhaust conduit, and the cooling jacket is positioned along a portion of the exhaust manifold.

11. The utility vehicle of claim 1, wherein: The catalyst includes a first catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit, and further includes a second catalyst positioned downstream of the first catalyst along the exhaust conduit.

12. The utility vehicle of claim 11, wherein: The second catalyst is positioned within the muffler of the exhaust assembly.

13. A multi-purpose vehicle comprising: a frame assembly extending along a longitudinal axis and defining an operator area; a plurality of ground contact members supporting the frame assembly and including front and rear ground contact members; at least one wheel well supported by the rear contact member; a powertrain assembly supported by the frame assembly and including at least an engine and a transmission operably coupled to the engine, wherein the engine is located longitudinally rearward of the operator area; as well as An exhaust assembly, the exhaust assembly comprising: an exhaust conduit fluidly coupled to the engine; a catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit, with the exhaust conduit, the engine, and the catalyst positioned adjacent one another along the longitudinal axis; and A cooling mechanism is configured to cool a portion of the exhaust assembly, the cooling mechanism including a deflection mechanism to direct air from at least one wheel well toward the portion of the exhaust assembly, wherein a velocity of the cooling air directed toward the portion of the exhaust assembly increases as the speed of the utility vehicle increases.

14. The utility vehicle of claim 13, wherein: The exhaust duct is positioned longitudinally intermediate the engine and the catalyst.

15. The utility vehicle of claim 13, wherein: The catalyst is positioned longitudinally intermediate the engine and the exhaust duct.

16. The utility vehicle of claim 13, wherein: The exhaust assembly further includes an exhaust gas constituent sensor supported by the exhaust conduit, and the exhaust gas is continuous between the exhaust gas constituent sensor and the catalyst.

17. The utility vehicle of claim 16, wherein: The sensor is positioned downstream of the catalyst.

18. The utility vehicle of claim 17, wherein: The exhaust assembly further includes a heat shield positioned adjacent the sensor.

19. The utility vehicle of claim 13, wherein: The exhaust assembly further includes a muffler, and the exhaust conduit includes a bellows, and the bellows is positioned within the utility vehicle at a location longitudinally intermediate the muffler and the engine.

20. An exhaust assembly for a utility vehicle having a front portion, a rear portion, a longitudinal axis extending between the front and rear portions, and a powertrain assembly including at least an engine and a transmission operatively coupled to the engine, the exhaust assembly comprising: an exhaust conduit fluidly coupled to the engine; a catalyst fluidly coupled to the exhaust conduit and configured to receive exhaust gas from the exhaust conduit, wherein the exhaust conduit, the engine, and the catalyst are positioned adjacent to one another along a longitudinal axis of the utility vehicle; and A cooling mechanism is configured to cool a portion of the exhaust assembly, the cooling mechanism including a deflection mechanism for directing air from a rear portion of the vehicle toward the portion of the exhaust assembly, wherein air is directed toward the portion of the exhaust assembly from at least two wheel wells of the utility vehicle; and wherein a rate of cooling air directed toward the portion of the exhaust assembly increases as the speed of the utility vehicle increases.

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