Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
  • F01N13/08—Other arrangements or adaptations of exhaust conduits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N1/00—Silencing apparatus characterised by method of silencing
  • F01N1/16—Silencing apparatus characterised by method of silencing by using movable parts
  • F01N1/166—Silencing apparatus characterised by method of silencing by using movable parts for changing gas flow path through the silencer or for adjusting the dimensions of a chamber or a pipe
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
  • F01N13/02—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate silencers in series
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
  • F02D9/04—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning exhaust conduits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
  • F02D9/08—Throttle valves specially adapted therefor; Arrangements of such valves in conduits
  • F02D9/10—Throttle valves specially adapted therefor; Arrangements of such valves in conduits having pivotally-mounted flaps
  • F02D9/1005—Details of the flap
  • F02D9/1025—Details of the flap the rotation axis of the flap being off-set from the flap center axis
  • F02D9/103—Details of the flap the rotation axis of the flap being off-set from the flap center axis the rotation axis being located at an edge
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
  • F02D9/08—Throttle valves specially adapted therefor; Arrangements of such valves in conduits
  • F02D9/10—Throttle valves specially adapted therefor; Arrangements of such valves in conduits having pivotally-mounted flaps
  • F02D9/1035—Details of the valve housing
  • F02D9/104—Shaping of the flow path in the vicinity of the flap, e.g. having inserts in the housing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
  • F02D9/08—Throttle valves specially adapted therefor; Arrangements of such valves in conduits
  • F02D9/10—Throttle valves specially adapted therefor; Arrangements of such valves in conduits having pivotally-mounted flaps
  • F02D9/1065—Mechanical control linkage between an actuator and the flap, e.g. including levers, gears, springs, clutches, limit stops of the like
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
  • F01N2240/36—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an exhaust flap

Definitions

• the subject invention relates to a valve assembly for a vehicle exhaust system.
• One aspect of the invention relates to a location of a passive valve in relation to other exhaust system components.
• Another aspect of the invention relates to a passive valve and resonator configuration, and more particularly relates to a passive valve in combination with a packed resonator.
• Another aspect of the invention relates to a passive valve with a stop pad that facilitates noise reduction while also improving valve performance and durability.
• Another aspect of the invention relates to a passive valve in a non-bypass configuration with a high percentage of coverage when in a closed position.
• Another aspect of the invention relates to passive valve that is offset within a vehicle exhaust system.
• Exhaust systems are widely known and used with combustion engines.
• an exhaust system includes exhaust tubes that convey hot exhaust gases from the engine to other exhaust system components, such as mufflers, resonators, etc.
• Mufflers and resonators include acoustic chambers that cancel out sound waves carried by the exhaust gases. Although effective, these components are often relatively large in size and provide limited nose attenuation.
• Passive valves have been used in a muffler to provide further noise attenuation.
• the proposed valves have numerous drawbacks that limit their widespread use in a variety of applications.
• One disadvantage with passive valves is their limited use in high temperature conditions.
• Another disadvantage with known passive valve configurations is that these valves do not effectively attenuate low frequency noise.
• additional challenges are presented when these types of valves are used in exhaust systems with multiple mufflers.
• One solution is to locate the passive valve outside of the muffler.
• An example of such a configuration is found in applicant's co-pending application 11/950,034 filed on December 4, 2007. While this solution has proven to be effective, other challenges are presented within the overall exhaust system by this type of mounting arrangement.
• a position of the passive valve in relation to other exhaust system components becomes an important characteristic from a noise reduction perspective.
• a specific position of the passive valve in the overall exhaust system is directly tied to the acoustic effectiveness of the valve. For example, positioning the valve at an acoustic velocity nodal point is ineffective.
• Additional challenges are also presented by multi-exhaust component systems, such as systems that include more than one muffler for example. Positioning the passive valve in front of a main muffler can give rise to chatter issues due to a higher level of pressure pulsations.
• the passive valve has been used within an exhaust pipe with a by-pass configuration.
• the passive valve includes a flapper valve body or vane that is positioned within the exhaust pipe, with the vane being pivotable between an open position and a closed position.
• the passive valve is spring biased toward the closed position, and when exhaust gas pressure is sufficient to overcome this spring bias, the vane is pivoted toward the open position.
• the vane provides 100% coverage, i.e. complete blockage, of the exhaust component when in the closed position.
• exhaust gases can flow outside of the exhaust pipe that houses the vane via a by-pass pipe that is connected to the exhaust pipe at locations upstream and downstream of the vane.
• the vane is generally configured such that, during pivotal movement, edges of the vane do not contact inner surfaces of the exhaust component. While use of such a valve improves low frequency noise attenuation, there is additional flow noise caused by turbulence generated at edges of the vane. Thus, while using the passive valve outside of the muffler has addressed certain problems, it has raised additional noise challenges that need to be addressed.
• the passive valve when used within an exhaust pipe, such as a pipe in a muffler or when used in a by-pass pipe configuration, challenges are presented when the passive valve is moved toward a fully open position.
• the vane When the vane is moved toward the fully open position, potential interference challenges are presented by the shape of the pipe itself.
• the vane has been supported by a shaft mounted to a wall of the pipe, with the shaft defining a pivot axis of rotation that is aligned with the vane, i.e. a plane defined by the vane intersects the pivot axis of rotation.
• the pipe typically includes a curved pipe wall having an inner surface that defines the exhaust gas flow path.
• an opening angle for the passive valve is limited by the width of the vane and the curvature of the wall. Limiting the opening angle is disadvantageous from a back pressure standpoint, in addition to failing to achieve a true fully open position for maximum flow.
• a muffler is subjected to different operating conditions dependent upon application. For example, due to its usual position, a main muffler for a passenger car can be subjected to exhaust gases of 600 degrees Celsius, while mufflers used in truck, minivan or SUV applications are subjected to gas temperatures that can exceed 750 degree Celsius.
• a passive noise attenuation valve has been directly incorporated within a muffler body to provide noise attenuation.
• This valve includes a spring for biasing a valve body for pivotable movement within a valve housing that defines an exhaust flow path.
• the spring has limited application in high temperature environments. Special high-temperature spring materials are often required, which can be very expensive. Also, these valves can be difficult to package in smaller sized mufflers, which are typically used as part of a multi-muffler configuration for larger vehicles such as trucks, SUVs, mini- vans, etc.
• these known passive valves are used in a configuration where a by-pass flow path is provided.
• this type of configuration has a primary flow path and a by-pass flow path for exhaust gases.
• the valve body is positioned within an internal muffler tube that defines the primary flow path.
• the valve body is configured to block 100% of the primary flow path when in the closed position.
• a by-pass tube is in fluid communication with the internal muffler tube at a position upstream of the valve body and at a position downstream of the valve body. Under certain conditions, such as when the primary flow path is 100% blocked for example, exhaust gases are directed around the valve body via the by-pass tube.
• a vehicle exhaust system includes a passive valve that is positioned within the exhaust system at a certain positional relationship to other exhaust components to provide a significant acoustic advantage of noise attenuation for the exhaust system as a whole.
• a vehicle exhaust system includes at least one muffler having an inlet and an outlet.
• a first pipe body is connected to the outlet and a second pipe body is connected to the inlet.
• a passive valve assembly is mounted within one of the first and second pipe bodies and is positioned at a location within a first 25% of an overall pipe length of a respective one of the pipe bodies relative to corresponding one of the inlet and outlet of the muffler.
• the first pipe body has first and second ends.
• the first end is located at the muffler, and the pipe body extends to a second end to define the overall pipe length.
• the first pipe body defines a sole exhaust flow path between the first and the second ends.
• a passive valve assembly is mounted within the first pipe body and is positioned at a location within a first 25% of the overall pipe length relative to the first end, which is positioned at the outlet of the muffler.
• the vehicle exhaust system includes at least first and second mufflers and an inter-pipe that connects the first muffler to the second muffler.
• the inter-pipe defines a sole exhaust gas flow path between the first and the second mufflers.
• the inter-pipe has a tube body with a first end connected to the first muffler and a second end connected to the second muffler.
• the tube body extends from the first end to the second end to define an overall inter-pipe length.
• the passive valve assembly is mounted within the tube body at a position between the first and the second ends.
• the passive valve assembly is positioned at a location within a first 25% of the overall pipe length relative to one of the first and the second ends.
• the valve is close to the velocity anti-node position for acoustic resonances that exist within the associated pipes.
• a vehicle exhaust system in another example configuration, includes first and second exhaust components with an inter-pipe that fluidly connects an outlet of the first exhaust component to an inlet of the second exhaust component.
• a passive valve is mounted within the inter-pipe.
• the second exhaust component defines an internal cavity that is at least partially packed with a high frequency absorption material. This packed configuration cooperates with the passive valve to effectively attenuate low and high frequency noise.
• the first and the second exhaust components comprise first and second mufflers or resonators and the inter-pipe comprises a sole exhaust gas flow path between the first outlet and the second inlet.
• the first exhaust component has a first inlet and a first outlet
• the second exhaust component defines an internal cavity that has a second inlet and a second outlet.
• the second inlet and the second outlet cooperate to define an internal flow path through the second exhaust component.
• the internal flow path occupies a portion of the internal cavity leaving a remaining portion.
• the remaining portion of the internal cavity is completely packed with a high frequency absorption material.
• the inter-pipe connects the first outlet with the second inlet, and the passive valve is mounted within the inter-pipe.
• the second exhaust component includes a pipe that connects the second inlet to the second outlet to define the internal flow path.
• the pipe is defined by a pipe diameter and the passive valve is mounted within the inter-pipe at a specified distance from the second inlet of the second exhaust component. In one example, this specified distance is a distance that is at least four times the pipe diameter of the internal flow path.
• the pipe includes a perforated section and the high frequency absorption material is positioned within the internal cavity to contact at least a portion of the perforated section. In one example, the high frequency absorption material contacts an entire length of the perforated section.
• a passive valve in another example exhaust system configuration, includes a vane that is positioned within an exhaust gas flow path.
• the vane is supported by a shaft and is pivotable between open and closed positions.
• a stop is also positioned within the exhaust gas flow path and defines a closed position for the vane.
• the vane comprises a body structure that has a first portion coupled to the shaft. The body structure extends from the first portion to a tip. When in the closed position, the tip of the body structure engages the stop. In this configuration, the stop is positioned furthest from an axis of rotation defined by the shaft. This reduces contact forces between the stop and the vane to provide improved durability.
• the stop comprises a ramped surface that begins upstream of the vane.
• An exhaust component has a wall with an external surface and an internal surface that defines the exhaust gas flow path.
• the ramped surface extends from the internal surface of the wall toward the vane.
• a stop end surface then extends from the ramped surface back toward the internal surface of the wall.
• the tip of the vane engages the stop end surface when the passive valve is in the closed position.
• the upstream ramped surface reduces backpressure, turbulence, and the generation of flow noise.
• a passive valve for a vehicle exhaust system is arranged in a non-bypass configuration and provides a high percentage of coverage when in a closed position.
• the passive valve assembly is mounted within an exhaust tube.
• the exhaust tube has a bore that defines an exhaust flow path having a cross-sectional area.
• One end of the exhaust tube is to be connected to a first exhaust component and a second end of the exhaust tube is to be connected to a second exhaust component such that the exhaust tube forms a sole exhaust path between the first and the second exhaust components.
• the passive valve assembly includes a vane that is mounted within the bore, and which is moveable between an open position and a closed position. A resilient member biases the vane toward the closed position. When the vane is in the closed position, the vane covers 80-97% of the cross-sectional area.
• a high-coverage single passive valve assembly is used in a non- bypass arrangement to effectively attenuate low frequency noise.
• an exhaust component in another example exhaust system configuration, includes a wall with an inner surface defining an exhaust gas flow path.
• a passive valve assembly includes a vane that is positioned within the exhaust gas flow path to be pivotable between open and closed positions.
• the vane is defined by a plane that extends across a width of the vane.
• the vane is supported by a shaft that defines an axis of rotation. The axis of rotation is offset from the plane of the vane.
• the exhaust component comprises a pipe having a curved inner wall surface.
• a housing is mounted to a curved outer surface of the pipe.
• At least one bushing is mounted within the housing to pivotally support the shaft.
• a resilient member biases the vane toward the closed position, and the vane is pivoted from the closed position towards the open position in response to an exhaust gas flow that exceeds a biasing force of the resilient member.
• the plane and the axis of rotation have a non-intersecting relationship and a connecting arm is used to maintain a spaced relationship between the plane and the axis of rotation.
• the connecting arm has one portion coupled to the shaft and another portion coupled to the vane.
• the connecting arm extends transversely to the plane and to the axis of rotation.
• the vane comprises a disc- shaped body having a greater width than thickness.
• the plane is defined across the width of the disc-shaped body.
• the vane By offsetting the plane from the vane, the vane can be pivoted to a fully open position to maximize flow without interfering with a curved inner surface of the wall of the pipe.
• Figure 1 shows a perspective view of an exhaust pipe component and passive assembly.
• Figure 2 shows an acoustic velocity mode shape for a pipe having open ends.
• Figure 3 shows one example of a passive valve in a vehicle exhaust system.
• Figure 4 shows another example of a passive valve in a vehicle exhaust system.
• Figure 5 shows another example of a passive valve in a vehicle exhaust system.
• Figure 6 shows one example of a passive valve in a vehicle exhaust system.
• Figure 7 shows a cross-sectional view of a rearmost exhaust component from Figure 6.
• Figure 8 shows a schematic view of a mounting location of the passive valve in relation to the exhaust component of Figure 7.
• Figure 9 is a schematic view of one example of a packed exhaust component with a perforated pipe.
• Figure 10 is a schematic view of another example of a packed exhaust component with a tuning pipe.
• Figure 11 shows a perspective view of one example of an exhaust component and passive valve assembly.
• Figure 12 shows a side view of an exhaust component with a stop for a vane.
• Figure 13A is a schematic side view showing a ramp surface angle of the stop relative to a centerline of the exhaust component.
• Figure 13B is a schematic side view showing an end surface angle of the stop relative to the centerline of the exhaust component.
• Figure 14 is a schematic side view of one example of a stop.
• Figure 15 is a schematic side view of another example of a stop.
• Figure 16A is a perspective view of another example of a stop.
• Figure 16B is an end view of the stop of Figure 16A.
• Figure 16C is a side view of the stop of Figure 16 A.
• Figure 1 6D is a top view of the stop of Figure 16A.
• Figure 17 shows a schematic view of a valve shaft, bushings, and spring as used in the assembly of Figure 1.
• Figure 18 shows a cross- sectional view of the spring of Figure 17.
• Figure 19 is a schematic side view of a spring and vane showing substantially closed and open positions.
• Figure 20 is a cross-sectional end view of an external exhaust tube and passive valve assembly with the vane being in the substantially closed position.
• Figure 21 is a perspective view of a muffler and an external exhaust tube with a passive valve assembly.
• Figure 22 shows a side view of an exhaust component with an offset vane.
• Figure 23 is a schematic side view of the exhaust component of Figure 22 in a fully open position.
• an exhaust component such as an exhaust tube or pipe 10 includes an exhaust throttling valve, referred to as a passive valve assembly 12.
• the passive valve assembly 12 is movable between an open position where there is minimal blockage of an exhaust gas flow path 16 and a closed position where a substantial portion of the exhaust gas flow path 16 is blocked.
• the passive valve assembly 12 is resiliently biased toward the closed position and is moved toward the open position when exhaust gas flow generates a pressure sufficient enough to overcome the biasing force.
• the exhaust pipe 10 comprises a single tube body 14 that defines the exhaust gas flow path 16.
• the passive valve assembly 12 includes a valve body or vane 18 that blocks a portion of the exhaust gas flow path 16 when in the closed position. As discussed above, the vane 18 is pivoted toward the open position to minimize blockage of the exhaust gas flow path 16 in response to pressure exerted against the vane 18 by exhaust gases.
• the vane 18 is fixed to a shaft 20 with a tang, bracket, or connecting arm 22.
• a slot 24 is formed within an outer surface of the pipe body 14.
• a housing 26, shown in this example as a square metal structure, is received within this slot 24 and is welded to the pipe body 14. Other housing configurations could also be used.
• the shaft 20 is rotatably supported within the housing 26 by first 28 and second 30 bushings or bearings.
• the connecting arm 22 comprises a piece of sheet metal that has one portion welded to the shaft 20 and another portion that extends outwardly from the housing 26 and is welded to the vane 18.
• the connection arm 22 is just one example of how the shaft 20 can be attached to the vane 18, it should be understood that other attachment mechanisms could also be used.
• the first bushing 28 is positioned generally at a first shaft end 32.
• the first bushing 28 comprises a sealed interface for the first shaft end 32.
• the shaft 20 includes a shaft body 34 that has a first collar 36 and a second collar 38.
• the first bushing 28 includes a first bore that receives the first shaft end 32 such that the first collar 36 abuts directly against an end face of the first bushing 28 to provide a sealed interface. As such, exhaust gases cannot leak out of the first bushing 28 along a path between the shaft 20 and first bushing 28.
• the second bushing 30 includes a second bore through which the shaft body 34 extends to a second shaft end 40.
• the second collar 38 is located axially inboard of the second bushing 30.
• the shaft 20 extends through the second bore to an axially outboard position relative to the second bushing 30.
• a resilient member such as a spring 42 for example, is coupled to the second shaft end 40 with a spring retainer 44.
• the spring retainer 44 includes a first retainer piece 46 that is fixed to the housing 26 and a second retainer piece 48 that is fixed to the second shaft end 40.
• One spring end 50 is associated with housing 26 via the first retainer piece 46 and a second spring end (not viewable in Figure 1 due to the spring retainer 44) is associated with the shaft 20 via the second retainer piece 48.
• the passive valve assembly 12 is advantageously positioned within a vehicle exhaust system at a certain positional relationship to other exhaust components to provide a significant acoustic advantage for overall noise attenuation.
• Figure 2 schematically shows a pipe 60 having open ends 62, 64. A typical acoustic velocity mode shape for this pipe configuration is shown at 66. It has been found that where the passive valve assembly 12 is positioned within an exhaust system determines its acoustic effectiveness. For example, positioning the passive valve assembly at an acoustic velocity nodal point P ( Figure 2) is ineffective for noise attenuation.
• FIG. 3 One example of a vehicle exhaust system 70 is shown in Figure 3.
• This configuration includes at least one muffler 72 that has an inlet 74 that receives exhaust gas flow from an engine as indicated at 76.
• the muffler 72 can comprises the only muffler in the vehicle exhaust system 70 or, if other mufflers are included in the vehicle exhaust system 70, the muffler 72 comprises a rearmost muffler in the vehicle exhaust system 70.
• the muffler 72 includes an outlet 78 that directs exhaust gases to a tailpipe 80.
• the outlet 78 can comprise a tube 82 that is coupled to a rear of the muffler 72 and coupled to the tailpipe 80, or the tube 82 can comprise the tailpipe 80 itself.
• the tube 82 forms the sole exhaust gas flow path between the muffler 72 and an outlet from the tailpipe 80, and the passive valve assembly 12 is the only valve located within this section of the exhaust system. In other words, there is no by-pass tube or path downstream of the muffler 72 for this configuration.
• the tube 82 is defined as having a first end 84 that is coupled to the outlet 78 and a second end 86 that extends to the outlet from the tailpipe 80.
• the tube 82 has an overall length that extends from the first end 84 to the second end 86. This overall length is referred to as a developed length of the pipe or tube.
• the overall length does not have to be a straight-line length, i.e. the first 84 and second 86 ends can be non-coaxial, and the overall length can be defined as a length that is comprised of straight and curved portions added together.
• a passive valve assembly 12a is mounted outside of, i.e. external to, the muffler 72 and within the tube 82 at a position between the first 84 and second 86 ends.
• the passive valve assembly 12a is positioned at a location within a first 25% of the overall pipe length relative to the first end 84 as indicated at 90a.
• a passive valve assembly 12b is located within a tube or pipe 75 that is fluidly connected to the inlet 74 of the muffler 72.
• This pipe 75 defines an overall pipe length and comprises a sole exhaust flow path between the muffler 72 and an upstream exhaust component.
• the passive valve assembly 12b is positioned at a location within a first 25% of the overall pipe length relative to the inlet 74 as indicated at 90b.
• FIG. 4 shows another example of a vehicle exhaust system 90.
• the inter-pipe 96 comprises the sole gas path between the first 92 and second 94 mufflers, i.e. a non-bypass configuration is provided, and the passive valve assembly 12 is the only valve located within this section of the exhaust system.
• the inter-pipe 96 includes a first end 98 that is coupled to an outlet 100 of the first muffler 92 and a second end 102 that is coupled to an inlet 104 of the second muffler 94.
• the inter-pipe 96 can be a single tube or can be comprised of multiple tube portions connected together to form a single tube between the first 92 and second 94 mufflers.
• the first muffler 92 includes an inlet 106 that receives exhaust gas flow from an engine as indicated at 108.
• the second muffler 94 includes an outlet 110 that is coupled to a tailpipe 112.
• the passive valve assembly 12 is mounted within the inter-pipe 96 and is located at a position between the first 98 and second 102 ends at a location within a first 25% of the overall pipe length relative to one of first 98 and second 102 ends.
• the passive valve assembly 12a is positioned within a first 25% of the overall pipe length relative to the first end 98 as indicated at 114.
• the passive valve assembly 12b is positioned within a first 25% of the overall pipe length relative to the second end 102 as indicated at 116.
• the acoustic attenuation benefit of positioning the valve assembly 12a or 12b close to the velocity anti-node positions for the acoustic resonances existing within the inter-pipe 96 between the first 92 and second 94 mufflers is provided.
• FIG. 5 Another example of an exhaust system 120 is shown in Figure 5. This example is similar to that of Figure 4 but includes an additional foremost muffler 122 that is connected to an engine 124 upstream of the first muffler 92.
• the first 92 and second 94 mufflers in this configuration comprise additional or secondary mufflers that are used to provide additional noise attenuation.
• the foremost muffler 122 has an inlet 126 that is in fluid communication with the engine 124 and an outlet 128 that is in fluid communication with the inlet 106 of the first muffler 92.
• the passive valve assembly 12 is located in the inter-pipe 96 at a location within a first 25% of the overall pipe length relative to the first end 98 as indicated at 130.
• FIG. 6 schematically shows another example configuration of a vehicle exhaust system 200 that includes at least one first resonator or muffler 202 and at least one second resonator or muffler 204.
• the first muffler 202 has an inlet 206 that receives exhaust gas flow from an engine as indicated at 208.
• the first muffler 202 includes an outlet 210 that directs exhaust gases to an inter-pipe 212.
• the inter-pipe 212 fluidly connects the outlet 210 of the first muffler 202 to an inlet 214 of the second muffler 204.
• the second muffler 204 includes an outlet 216 that is fluidly connected to a tailpipe 218.
• the inter-pipe 212 can be a single tube or can be comprised of multiple tube portions connected together to form a single tube between the first 202 and second 204 mufflers.
• the tailpipe 218 can be a single tube or can be comprised of multiple tube portions connected together to form a single flow gas exit from the exhaust system 200.
• the inter-pipe 212 forms the sole exhaust gas flow path between the first 202 and second 204 mufflers. In other words, there is no by-pass flow option within the fluid connections between the first 202 and second 204 mufflers.
• the inter-pipe 212 extends from a first end 220 to a second end 222 to define an overall pipe length referred to as a developed length of the pipe.
• the first 220 and second 222 ends need not be co-axial, thus the developed length of the pipe can be comprised of a single straight section of pipe or can be comprised of a combination of straight and curved sections of pipe having their lengths added together.
• the passive valve assembly 12 is mounted external to the first 202 and second mufflers 204 and within the inter-pipe 212.
• the passive valve assembly 12 is positioned within the inter-pipe 212 between the first 220 and second 222 ends at a specified location in relation to the second muffler 204. This will be discussed in greater detail below.
• Figure 7 shows a cross-sectional view of the second muffler 204.
• the second muffler 204 defines an internal cavity 224 that has the single inlet 214 and the single outlet 216.
• the inlet 214 and outlet 216 cooperate to define the sole internal flow path 226 within the second muffler 204.
• This internal flow path 226 occupies a specified portion of the internal cavity 224 leaving a remaining portion that is not occupied by the internal flow path 226. This remaining portion is packed with a high frequency absorption material 228.
• a fiber-based material is used, however, any suitable material for attenuating high frequency noise can be used.
• the sole internal flow path 226 is contained within a pipe body 230 that extends from the inlet 214 to the outlet 216, and the high frequency absorption material 228 completely fills the internal cavity 224 to completely surround the pipe body 230.
• This completely packed configuration is the most common configuration and is the most efficient configuration from an assembly and manufacturing perspective.
• the passive valve assembly 12 is mounted within the inter-pipe 212 at a specified distance relative to the inlet 214 of the second muffler 204 as indicated at 232.
• the pipe body 230 is defined by a pipe diameter D.
• This pipe diameter D can vary depending upon the type of vehicle application and/or other exhaust system characteristics.
• the passive valve assembly 12 is positioned at a distance 232 that is at least four times the pipe diameter D that defines the internal flow path 226.
• a pipe 250 extends from the inlet 214 to the outlet 216 to define a sole internal flow path 252.
• the pipe 250 includes a perforated section 254.
• the perforated section 254 is positioned within the internal cavity 224 and extends along a portion of an overall length of the pipe 250. As such, a length L of the perforated section 254 is less than the overall length of the pipe 250.
• the perforated section 254 at least partially extends about an outer circumference of the pipe 250, and in the example shown, extends entirely about the outer circumference of the pipe 250.
• the high frequency absorption material 228 is positioned with the internal cavity 224 to contact at least a portion of the perforated section 254 to provide a packed configuration.
• the high frequency absorption material 228 is positioned to contact the entire length L of the perforated section 254.
• the high frequency absorption material 228 can comprise material that is packed around the pipe to provide this contact, or the high frequency absorption material 228 can comprise a mat that is wrapped around the perforated section 254.
• the high frequency absorption material 228 also contacts the pipe 250 along non-perforated sections 256.
• the pipe 250 can also include sections within the internal cavity 224 that are not in contact with high frequency absorption material 228.
• the high frequency absorption material 228 does contact the entire length L of the perforated section 254 to provide the most effective attenuation of high frequency noise.
• a tuning tube 260 is connected to the pipe 250 at one of the non-perforated sections 256 to provide additional noise attenuation.
• the tuning tube 260 is not at a location of the pipe 250 that is contact with high frequency absorption material 228.
• high frequency absorption material 228 could also be used on the pipe 250 at the tuning tube location.
• the tuning tube 260 could also be used in the configuration shown in Figures 6-8.
• the passive valve assembly 12 is mounted within the inter-pipe 212 at a specified location relative to the inlet 214 of the second muffler 204 as described above in the examples of Figures 6-8.
• the pipe body 230 shown in Figures 7 and 8 could include a perforated section in combination with a completely packed internal cavity.
• the use of a packed high frequency muffler downstream of a throttling, spring-biased passive valve provides an effective configuration for attenuating noise.
• the passive valve assembly 12 which is effective for attenuating low frequency noises, cooperates with the packed muffler, which is effective for attenuating high frequency noise, to provide an exhaust system with significantly improved noise attenuation capability.
• Figure 11 shows the exhaust pipe 10 and the passive valve assembly 12 in combination with a stop feature.
• the exhaust pipe 10 comprises a single pipe body 14 that defines the exhaust gas flow path 16.
• the pipe body 14 includes a curved outer surface 14a and a curved inner surface 14b that defines the exhaust gas flow path 16.
• the pipe body 14 has a circular cross-section.
• the passive valve assembly 12 includes a valve body or vane 18 that blocks a portion of the exhaust gas flow path 16 when in the closed position. As discussed above, the vane 18 is pivoted toward the open position to minimize blockage of the exhaust gas flow path 16 in response to pressure exerted against the vane 18 by exhaust gases.
• the vane 18 comprises a body structure 300, such as a disc-shaped body for example, which includes a first portion 302 that is coupled to the shaft 20 with the connecting arm 22.
• the body structure 300 extends from the first portion 302 to a second portion that comprises a distal tip 304.
• the tip 304 comprises a portion of the body structure 300 that is furthest from the axis of rotation A.
• a stop 306 is supported by the pipe body 14 and is positioned within the exhaust gas flow path 16.
• the stop 306 defines the closed position for the vane 18.
• the tip 304 of the vane 18 engages the stop 306 when the spring 42 returns the vane 18 from the open position to the closed position.
• the stop 306 comprises a ramped surface 308 that begins at the inner surface 14b at a position upstream from the vane 18 and extends outwardly away from the inner surface 14b and towards the vane 18.
• the ramped surface 308 then transitions into a stopper end surface 310 that extends back towards the inner surface 14b.
• the tip 304 of the vane 18 engages the stopper end surface 310 when in the closed position.
• the ramped surface 308 and the stopper end surface 310 are angled relative to the inner surface 14b of the pipe body 14.
• the pipe body 14 defines a pipe centerline C, which is shown in Figure 12.
• the ramped surface 308 is positioned at a ramp angle A that is within a range of 10 to 45 degrees relative to the pipe centerline C.
• the stopper end surface 310 ( Figure 13B) is positioned at an angle B relative to the pipe centerline C.
• the ramped surface 308 and the stopper end surface 310 are obliquely orientated relative to the inner surface 14b and relative to the pipe centerline C.
• a pad 312 is supported on the stopper end surface 310 to provide a cushioned surface to engage the tip 304 of the vane 18.
• the pad 312 can be made from a mesh material or other similar material, for example, and can be attached to the stopper end surface 310 with any type of attachment method suitable for use within an exhaust component.
• the stop 306 is positioned at the tip 304 of the vane 18 to minimize closing forces. By positioning these contact surfaces as far as possible from the axis of rotation A, contact forces are reduced, which in turn increases durability. Further, the upstream ramped surface 308 of the stop 306 reduces backpressure, turbulence, and the generation of additional flow noise. [00100]
• the stop 306 is formed as one piece with the wall of the pipe body 14 as shown in Figure 14. A tool 314 is used to indent a portion 316 of the pipe body 14 itself to form the stop 306. The pad 312 can then be attached to the stopper end surface 310 as discussed above.
• the stop 306 comprises a separate body 320 that is welded to the inner surface 14b of the pipe body 14 as indicated at 322.
• the pad 312 can then be attached as described above.
• the pad 312 and the separate body 320 can be made from common materials, or the pad 312 can be made from a different material that is attached to the stop 306.
• the stop 306 comprises a duckbill portion 330 that is positioned upstream of the stopper end surface 310.
• the duckbill portion 330 has a radius of curvature R that is contoured to match the inner surface 14b of the pipe body 14.
• the duckbill portion 330 is spot welded, as indicated at 332, to the pipe body 14.
• the duckbill portion 330 transitions into the ramped surface 308, which in this example comprises a curved surface.
• the ramped surface 308 terminates at the stopper end surface 310, which extends back toward the inner surface 14b of the pipe body 14 in a direction away from a centerline of the pipe body 14.
• the duckbill portion 330 is formed as one-piece with the ramped surface 308 and the stopper end surface 310.
• the pad 312 can be attached to the stopper end surface 310 as described above.
• the subject passive valve assembly 12 with the stop 306 and pad 312 can effectively and efficiently return a vane 18 to a consistent, repeatable closed position without generating additional unwanted noise. Additionally, the pad 312 is positioned adjacent the tip 304 of the vane 18 to minimize closing forces and to improve durability of the passive valve assembly. Further, the orientation and position of the ramped surface 308 of the stop 306 also reduces noise in addition to reducing backpressure and turbulence.
• FIG 17 shows the shaft 20, spring 42, and bushings 28, 30 in greater detail.
• the first bushing 28 is positioned generally at the first shaft end 32 and comprises a sealed interface for the first shaft end 32.
• the shaft 20 includes a shaft body 400 that is defined by a first diameter Dl.
• Near the first shaft end 32 is the first collar 36, which is defined by a second diameter D2 that is greater than the first diameter Dl.
• the first bushing 28 includes a first bore 402 that receives the first shaft end 32.
• the first collar 36 abuts directly against an end face 404 of the first bushing 28 such that exhaust gas cannot leak out of the first bushing 28 along a path between the shaft 20 and first bushing 28.
• the second bushing 30 includes a second bore 406 through which the shaft body 400 extends to the second shaft end 40.
• the shaft 20 includes the second collar 38, which is defined by a third diameter D3.
• the third diameter D3 is greater than the first diameter Dl.
• the second D2 and third D3 diameters can be the same or different from each other.
• the second collar 38 is located axially inboard of the second bushing 30.
• the shaft 20 extends through the second bore 406 to an axially outboard position relative to the second bushing 30.
• the spring 42 is coupled to the second shaft end 40 with the spring retainer 44.
• the spring retainer 44 includes the first retainer piece 46 that is fixed to the housing 26 and the second retainer piece 48 that is fixed to the second shaft end 40.
• One spring end 50 is associated with housing 26 via the first retainer piece 46 and a second spring end 408 ( Figure 18) is associated with the shaft 20 via the second retainer piece 48.
• the spring 42 is located external to, i.e. outside of, the pipe body 14. As such, the spring 42 operates in a much cooler environment instead of being subjected directly to the high temperature exhaust gases as in prior designs.
• the spring 42 comprises a coil spring that is configured to be compressed both in an axial direction along axis A and in a torsional direction about the axis A during installation.
• Torsional loading creates a preload force that biases the shaft 20 and the vane 18 toward the closed position. As gas flow increases, this torsional force is overcome to move the vane 18 toward the open position.
• the axial force serves to positively seat and seal the second collar 38 against an end face 410 of the second bushing 30. This prevents any exhaust gas from leaking out of the second bushing 30 by sealing off a passage between an outer surface of the shaft 20 and a bore surface of the second bushing 30.
• a single spring is used to provide both axial and torsional loading, resulting in a configuration that can both hold the passive valve assembly 12 in a desired operational position as well as preventing exhaust gas leakage.
• the spring 42 is shown in greater detail in Figure 18.
• the spring 42 is a coil spring formed from wire having a diameter Dw. Prior to installation, the spring 42 is defined by a free length condition FL where a first pitch dimension Pl is greater than the diameter Dw. This relationship results in spacing between adjacent coils by a gap 412. The gaps 412 between adjacent coils enable the spring 42 to be compressed in the axial direction as well as in the torsional direction during installation. This results in a second pitch dimension P2 ( Figure 1) that is less than the first pitch dimension Pl.
• the spring 42 has a wire diameter Dw that is approximately 1.8 mm, and a first pitch dimension Pl that is greater than 2 mm.
• the spring 42 also has an overall outer diameter of 17 mm and a free length FL of approximately 30 mm. When compressed for installation this free length FL is reduced by approximately 5 mm. It should be understood that this is just one example configuration and that other configurations could be used as needed to provide desired characteristics.
• the shaft By utilizing a single spring that can act both in torsion and axially, the shaft can be loaded against the bushing, which will minimize exhaust gas leakage between the shaft and the bushing. Further, this configuration can be used to minimize build up variations because the shaft will always be positively located against the bushing.
• the passive valve assembly 12 also provides a significant amount of coverage of the exhaust gas flow path 16 when in the closed position as compared to prior valves, which have 50% or less coverage when closed.
• the passive valve assembly 12 is positioned in an exhaust tube 420 having a first tube end 422 that is connected to a first exhaust component 424 and a second tube end 426 that is connected to a second exhaust component 428.
• the first 424 and second 428 exhaust components can comprise components such as a muffler, tailpipe, etc.
• the first exhaust component 424 comprises a muffler 430 and the second exhaust component 428 comprises a tailpipe 432.
• the exhaust tube 420 is connected to an outlet 434 of the muffler 430 and an inlet to the tailpipe 432.
• both the first 424 and second 428 components comprise mufflers (schematically shown in Figure 19) with the exhaust tube 420 being connected to an outlet from one muffler and to an inlet from another muffler.
• the exhaust tube 420 has an internal bore or opening 436 that fluidly connects the first 424 and second 428 exhaust components and defines the exhaust gas flow path 16.
• the exhaust gas flow path 16 is sole flow path between the first 424 and second 428 exhaust components. In other words, there is no by-pass flow path associated with the exhaust tube 420, and the only path through which exhaust gases can flow is exhaust gas flow path 16 within the exhaust tube 420
• the vane 18 is pivotable within the opening 436 from a substantially closed position (solid line) to a substantially open position (dashed line).
• the vane 18 is biased by the spring 42 (shown schematically) toward the closed position as schematically indicated at 440.
• exhaust gas pressure indicated by arrow 442
• exceeds a certain level the spring force is overcome and the vane 18 is moved toward the open position.
• the opening 436 is defined by a cross-sectional area.
• this cross-sectional area is covered, i.e. closed off, by approximately 80-97%.
• the cross-sectional area is covered within a range of 87.5-92.5%.
• This high percentage of coverage in combination with a non-bypass configuration, provides a very effective way to attenuate low frequency noise.
• Figures 22-23 show an example an offset passive valve configuration.
• the pipe body 14 includes a curved outer surface 14a and a curved inner surface 14b that defines the exhaust gas flow path 16 (Figure 1).
• the vane 18 comprises a disc-shaped body 500 that is generally flat, and which has a significantly greater width W (Figure 1) or diameter than a thickness t (Figure 22) of the disc- shaped body 60.
• the vane 18 defines a plane (a vane center plane) P ( Figure 22) that extends across the width W of the disc-shaped body 500. It should be noted that the thickness t of the disc-shaped body 500 is exaggerated in Figure 22 to clearly show the plane P.
• the plane P is offset from the axis of rotation A by a distance D.
• This distance D remains generally constant as the vane 18 is pivoted between the open and closed positions, and as such, the plane P and the axis of rotation A have a non- intersecting relationship.
• the vane 18 can be pivoted to a fully open position as shown in Figure 23 without interfering with the curved inner surface 14b of a wall of the pipe body 14.
• the exhaust gas flow path 16 extends in a first direction, indicated by arrow 502, and the axis of rotation A extends in a second direction that is different than the first direction.
• the plane P is offset from the axis of rotation A in the first direction.
• the first and second directions are perpendicular to each other and the plane P is positioned in the exhaust gas flow path 16 at a location upstream from the axis of rotation A.
• the connecting arm 22 includes a first portion 504 that is coupled to the shaft 20 and a second portion 506 that is coupled to the vane 18.
• the connecting arm 22 is welded to the shaft 20 and vane 18 at the first 504 and second 506 portions, respectively.
• the connecting arm 22 extends transversely to both the plane P and the axis of rotation A. In one example, the connecting arm 22 is perpendicular to the axis of rotation A and the plane P.
• the pipe body 14 extends longitudinally, i.e. along a length, to define a center axis C that coincides with a center of the exhaust gas flow path 16.
• the plane P of the vane 18 is generally parallel to, and offset from, the center axis C when the vane 18 is in the open position to provide a fully open, maximum flow, position.
• the offset relationship between the vane 18 and the shaft 20 provided by the transversely extending connecting arm 22 allows minimal blockage when open, i.e. maximizes the opening angle, which results in minimal backpressure.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust Silencers (AREA)
• Check Valves (AREA)

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• 2008
  • 2008-11-18 CN CN201410045177.3A patent/CN103790678B/zh active Active
  • 2008-11-18 WO PCT/US2008/083866 patent/WO2009067430A2/en active Application Filing
  • 2008-11-18 EP EP08851763A patent/EP2232031A2/en not_active Withdrawn
  • 2008-11-18 KR KR1020107012712A patent/KR20100105593A/ko not_active Application Discontinuation

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