Patent Publication Number: US-10323610-B2

Title: Noise attenuation device for an intake system of an internal combustion engine

Description:
FIELD 
     The present description relates generally to reducing noise caused by turbulent air flow in an intake manifold of a passenger vehicle traveling on the road. 
     BACKGROUND/SUMMARY 
     Intake manifolds may be formed with plastics in an effort to reduce vehicle cost and weight. However, plastic components are less dense than an equivalent metal component, which may lead to certain issues. For example, during vehicle travel, a noise may be generated by an air flow pattern at various throttle valve angles, including but not limited to tip-in or fast opening. The noise may penetrate the plastic passageways and radiate to a driver of the vehicle, resulting in undesirable sounds. 
     One example approach to reduce this noise is shown by Choi et al. in U.S. Pat. No. 5,722,357. Therein, an air diffuser is located between a throttle body and an intake manifold with radial vanes protruding into an intake path. The air diffuser may disrupt an air flow pattern and reduce noise emanating from the intake manifold. 
     However, the inventors herein have recognized a disadvantage with prior art noise reduction system for intake air passages. As one example, these noise reduction systems may decrease bulk airflow due to their protrusion into the intake path for a given throttle bore size, which may ultimately decrease an engine power output. Furthermore, such intake systems may have discontinuities so that the system can be packaged into the vehicle. Air flowing around these discontinuities can produce noise due to turbulent intake air flow. This noise can be bothersome to customers. Additionally, while increasing throttle bore may be used to counteract flow restrictions, this may cause still other problems related to not only packaging, but also airflow controllability which can be particularly relevant to idle speed control, air-fuel ratio control, etc. 
     In one example, the issues described above may be addressed by an intake system comprising a throttle body in an intake passage with a bore having a first radius smaller than a second radius of the intake passage and a noise attenuation device with a plurality of vanes located in the intake passage directly downstream of the throttle body and where a maximum height of the vanes is substantially equal to a difference between the radius. In this way, the vanes may decrease noise while not decreasing bulk airflow. 
     As one example, the vanes extend inwardly into the intake passage for a predetermined height equal to or less than the difference the first and second radius. The vanes may diffuse and/or redirect air flow that may otherwise impinge onto surfaces of the intake passage and produce an undesired noise. By diffusing the intake flow, the noise may be decreased or prevented such that it may not emanate from the intake passage. 
     It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic of an example engine. 
         FIG. 2  shows a cross-sectional view of an intake passage with a throttle body and a noise attenuation device located therein. 
         FIG. 3  shows a face-on view of the throttle body and noise attenuation device. 
         FIG. 4  shows a first embodiment of the noise attenuation device. 
         FIG. 5  shows a second embodiment of the noise attenuation device. 
         FIG. 6  shows a third embodiment of the noise attenuation device. 
         FIG. 7  shows a fourth embodiment of the noise attenuation device. 
         FIGS. 2-7  are shown approximately to scale, however other embodiments may be used. 
     
    
    
     DETAILED DESCRIPTION 
     The following description relates to systems for a noise attenuation device directly downstream a throttle body of an intake passage. An engine utilizing the intake passage is shown in  FIG. 1 . The noise attenuation device is welded to the throttle body via an upstream face and welded to the intake passage via a base. A height of the noise attenuation device is substantially equal to a difference between a radius of the throttle body and a radius of the intake passage, as shown in  FIG. 2 . An upstream-to-downstream view of the noise attenuation device located directly downstream of a transparent throttle body is shown in  FIG. 3 .  FIGS. 4, 5, 6, and 7  show various embodiments of the noise attenuation device. 
       FIGS. 2-7  show example configurations with relative positioning of the various components. If shown directly contacting each other, or directly coupled, then such elements may be referred to as directly contacting or directly coupled, respectively, at least in one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to each other, respectively, at least in one example. As an example, components laying in face-sharing contact with each other may be referred to as in face-sharing contact. As another example, elements positioned apart from each other with only a space there-between and no other components may be referred to as such, in at least one example. 
       FIG. 1  shows a schematic depiction of a vehicle system  6 . The vehicle system  6  includes an engine system  8 . The engine system  8  may include an engine  10  having a plurality of cylinders  30 . Engine  10  includes an engine intake system  23  and an engine exhaust  25 . Engine intake system  23  includes a throttle  62  fluidly coupled to the engine intake manifold  44  via an intake passage  42 . The throttle  62  includes a first bore concentric with a second bore of the intake passage  42 . In one example, the first bore has a first radius smaller than a second radius of the second bore. The engine exhaust  25  includes an exhaust manifold  48  eventually leading to an exhaust passage  35  that routes exhaust gas to the atmosphere. Throttle  62  may be located in intake passage  42  downstream of a boosting device, such as a turbocharger (not shown), and upstream of an after-cooler (not shown). When included, the after-cooler may be configured to reduce the temperature of intake air compressed by the boosting device. 
     A noise attenuation device  64  may be located downstream of the throttle  62  along a bottom portion of the intake passage  42 . As shown, the noise attenuation device  64  is coupled to a lowest portion of the intake passage  42 . The throttle  62  comprises a throttle valve  63  which may rotate based on an engine load to restrict intake flow. The throttle valve  63  may direct intake flow such that turbulent intake flow may impinge on lower interior surfaces of the intake passage  42  generating audible sounds. The noise attenuation device  64  may comprise a plurality of vanes extending inwardly for diffusing and redirecting the intake flow. The vanes protrude only partially into the intake passage  42  and do not span across the intake passage as will be described below. 
     Engine exhaust  25  may include one or more emission control devices  70 , which may be mounted in a close-coupled position in the exhaust. One or more emission control devices may include a three-way catalyst, lean NOx filter, SCR catalyst, etc. Engine exhaust  25  may also include a PF  102 , which temporarily filters PMs from entering gases, positioned upstream of emission control device  70 . In one example, as depicted, PF  102  is a gasoline particulate matter retaining system. PF  102  may have a monolith structure made of, for example, cordierite or silicon carbide, with a plurality of channels inside for filtering particulate matter from diesel exhaust gas. Tailpipe exhaust gas that has been filtered of PMs, following passage through PF  102 , may be measured in a PM sensor  106  and further processed in emission control device  70  and expelled to the atmosphere via exhaust passage  35 . 
     The vehicle system  6  may further include control system  14 . Control system  14  is shown receiving information from a plurality of sensors  16  (various examples of which are described herein) and sending control signals to a plurality of actuators  81  (various examples of which are described herein). As one example, sensors  16  may include exhaust flow rate sensor  126  configured to measure a flow rate of exhaust gas through the exhaust passage  35 , exhaust gas sensor (located in exhaust manifold  48 ), temperature sensor  128 , pressure sensor  129  (located downstream of emission control device  70 ), and PM sensor  106 . Other sensors such as additional pressure, temperature, air/fuel ratio, exhaust flow rate and composition sensors may be coupled to various locations in the vehicle system  6 . As another example, the actuators may include fuel injectors  66 , throttle  62 , spark plugs  68 , aftertreatment valves that control filter regeneration (not shown), a motor actuator controlling PM sensor opening (e.g., controller opening of a valve or plate in an inlet of the PM sensor), etc. Thus, engine  10  may be a spark ignited (gasoline engine). In some embodiments, spark plugs  68  may be omitted and engine  10  may be a diesel engine. The control system  14  may include a controller  12 . The controller  12  may be configured with computer readable instructions stored on non-transitory memory. The controller  12  receives signals from the various sensors of  FIG. 1 , processes the signals, and employs the various actuators of  FIG. 1  to adjust engine operation based on the received signals and instructions stored on a memory of the controller. 
     Thus, the vehicle system may be used in a passenger vehicle. A method of operating an intake system in a passenger vehicle traveling on the road may comprise directing an intake flow to an engine of the vehicle via an intake passage, where the passage includes a throttle body with a bore generating upstream and downstream discontinuities and where a set of vanes is located adjacent to one of the discontinuities. The throttle valve is operated to adjust a volume of intake flow in the intake passage. The vanes protrude into the intake passage for a predetermined distance equal to a height of one of the discontinuities. Therefore, the vanes protrude only partially into the intake passage and do not span across the intake passage. The discontinuities arise from a difference between a first radius of the bore of the throttle body and a second diameter of the intake passage, where the first radius is smaller than the second radius. Thus, the predetermined distance is substantially equal to the difference, which is substantially equal to the height of one of the discontinuities. The vanes (noise attenuation device) may be pressed against or spaced away from one or more of the upstream and downstream discontinuities. In one example, the noise attenuation device is located only behind the downstream discontinuity. 
       FIG. 2  shows a cross-sectional view of an intake system  200  with a noise attenuation device  220  located directly downstream of a throttle body  208 . The noise attenuation device  220  (noise attenuation device  64  in the embodiment of  FIG. 1 ) is configured to diffuse and redirect air flowing from the throttle body  208  (throttle  62  in the embodiment of  FIG. 1 ) toward an engine (engine  10  in the embodiment  FIG. 1 ) to decrease noises emanating from an intake system of a moving vehicle during some engine operating conditions. It will be appreciated that intake system  200  is shown in simplified form by way of example and that other configurations are possible. 
     An axes system  290  comprises two axes, namely a horizontal axis and a vertical (axial) axis. A central axis  295  of an intake pipe  202  is parallel to the horizontal axis. Arrow  297  depicts a general direction of intake gas parallel to the horizontal axis inside the intake pipe  202 . The intake pipe  202  defines an outer boundary of an intake passage  201  and therefore includes a bore located therein. 
     The throttle body  208  divides an intake passage  201  (e.g., intake passage  42  in the embodiment of  FIG. 1 ) within the intake pipe  202  into two separate segments, an upstream intake passage  204  and a downstream intake passage  206 . The upstream  204  and downstream  206  intake passages sandwich the throttle body  208  and may be substantially fluidly separated when a valve  212  of the throttle body  208  is in a closed position. Therefore, the upstream  204  and downstream  206  intake passage are fluidly coupled for a valve  212  outside of the closed position (at least partially open position). For a valve  212  in an at least partially open position, intake air initially flows through the upstream intake passage  204 , through a bore  210  of the throttle body  208 , and into the downstream passage  206 . In this way, the intake passage  201  (upstream intake passage  204 , bore  210 , and downstream intake passage  206 ) is a contiguous pathway. An amount of air flowing from the upstream intake passage  204  to the downstream intake passage  206  may be adjusted by the throttle valve  212 . A more open position of the throttle valve  212  allows a greater mass of air to flow into the downstream intake passage  206  than a more closed position of the throttle valve  212 . Thus, the throttle valve  212  may rotate via a rotating device  214  with a range of motion of 90°, 180°, or 360°. In this way, the throttle valve may be perpendicular to the central axis  295  (fully closed) or parallel to the central axis (fully open). The fully closed position may allow at least a minimum amount of air into the downstream intake passage  206  and the fully open position may allow a maximum amount of air into the downstream intake passage. In this way, the throttle valve  212  in the closed position may be minimally spaced away from the throttle body  208 . 
     The throttle body  208  comprises an annular, contiguous first bore wall  216 . Wall  216  defines the bore  210 , with edges of the wall  216  blocking outer portions of the intake passage  201 . Thus, wall  216  has a first (inner) radius  272  smaller than a second radius  274  of the bore of intake pipe  202 . Thus, the intake pipe  202  may serve as a second bore wall defining the bore of the intake passage  201 . The wall  216  may be thicker than and misaligned with the intake pipe  202 , such that a difference  270  between the radiuses extends around an entire inner circumference of the intake pipe  202 . In this way, the wall  216  is sized such that a portion of the wall  216  extends into the intake passage  201 , narrowing an area for intake flow to flow through at the throttle body  208 . Thus, the wall  216  generates discontinuities in the intake passage  201  due to a change in radius as described above. 
     Intake flow (e.g., motive flow, EGR, ram air, etc.) may collide with lower interior surfaces of the downstream intake passage  206  adjacent the throttle body  208  (below the central axis  295 ). Uninterrupted (turbulent) flow of intake air in this way may produce undesirable audible noises. Specifically, noise may be generated near an interface between the throttle body  208  and the downstream intake passage  206  during some engine conditions based on a position of the throttle valve  212 . The noise attenuation device  220  may decrease and/or prevent a generation of the audible sound by altering the intake air flow. The noise attenuation device comprises features (vanes) for diffusing the intake air flow through a range of valve positions, as will be described below. The noise attenuation device  220  is shown only on the bottom portion of the downstream intake passage  206 , but may be located around an entire inner circumference of the downstream intake passage adjacent to the throttle body  208 . As shown, a height  276  of the noise attenuation device is substantially equal to the difference  270  between first  272  and second  274  radius of the bore  210  and the intake pipe  202 , respectively. Substantially equal may be defined as the height and the difference deviating from each other due to production induced tolerances by 2-5% in one example. In one example, the height  276  may be a maximum height of the noise attenuation device  220 . Thus, the noise attenuation device  220  does not extend into an air space of the intake passage  201  directly downstream of the bore  210 . In some embodiments, the height  276  may be shorter than the discontinuity  270 . In this way, the noise attenuation device does not inhibit intake air flow while providing greater noise attenuation capabilities compared to the prior art, which extends beyond the difference  270 . 
     The noise attenuation device  220  is shown coupled to the wall  216  and the lower portion of the downstream intake passage  206  adjacent the wall  216 . Specifically, an upstream face  222  is in face-sharing contact with a downstream side  218  of the wall  216  of the throttle body  208  and a base  224  is coupled to the intake pipe  202 . The noise attenuation device may be coupled to the wall  216  and the downstream intake passage  206  via welds, adhesives, etc., as will be described below. Alternatively, in one example, a lower portion of the wall  216  may be manufactured with grooves, notches, and/or other locking features corresponding to locking features manufactured onto the upstream face  222  of the noise attenuation device  220 . In this way, the noise attenuation device  220  may be more accessible and easier to replace than a molded noise attenuation device. In another example, the intake conduit  202  and the noise attenuation device  220  may be manufactured as a single, contiguous piece. The upstream face  222  and downstream face  228  are normal to a direction of intake flow (arrow  297 ) and the base  224  and a top face  226  of the noise attenuation device  220  are parallel to a direction of intake flow. The noise attenuation device comprises a rectangular cross-section. It will be appreciated that the noise attenuation device may comprise other suitably shaped cross-sections, for example, triangular, without departing from the scope of the present disclosure. In some examples, the upstream face  222  may be spaced away from the throttle body  208  with only the base  224  anchoring the noise attenuation device  220  in the intake passage  201 . Additionally or alternatively, there may be a second noise attenuation device located upstream of the throttle body  208  at an interface between the throttle body and the intake conduit  202  in a lower portion (below the central axis  295 ) of the upstream intake passage  204 . Features of the noise attenuation device  220  will be described in greater detail with respect to  FIGS. 3-7 . It will be appreciated by someone skilled in the art that the noise attenuation device may be used in other flowing systems using similar valves and/or assembled joints as those described above, for example, in an HVAC or compressed air system. For example, a gas and/or fluid flow system may include a valve body, such as a throttle body or flap valve or other valve, in a passage with a bore having a first radius smaller than a second radius of the passage, and a noise attenuation device with a plurality of vanes located in the passage directly downstream of the valve body where a maximum height of the vanes is substantially equal to a difference between the radiuses. The system may be one where the vanes have at least some protrusion as compared with immediately downstream of the vanes, and/or the vanes have an upstream surface in face sharing contact with the expansion region between the unequal radiuses, and/or one or more of the various features described herein with regard to  FIGS. 1-7 . 
     For example, an intake system may comprise a throttle body in an intake passage with a bore having a first radius smaller than a second radius meter of the intake passage. A valve is mounted within the first bore and being moveable to selectively restrict intake flow. A noise attenuation device with a plurality of vanes may be located in the intake passage directly downstream of the throttle body and where a height of the vanes is substantially equal to a difference between the radius. The plurality of vanes extend inwardly from a base of the noise attenuation device into the intake passage, where the vanes are configured to diffuse and/or redirect intake flow. The noise attenuation device (vanes) may be pressed against or spaced away from the throttle body depending on a configuration of the intake passage and/or a noise characteristic of the intake system. The vanes extend inwardly into the intake passage for a predetermined distance, where the predetermined distance is based on a circumference of the bore of the throttle body. 
       FIG. 3  shows an upstream-to-downstream (face-on) view  300  of a throttle body  310  and a noise attenuation device  320 . The throttle body  310  is transparent (as indicated by small dash lines) to illustrate the noise attenuation device  320  in the view  300  that would otherwise be occluded by the throttle body. The throttle body  310  may be used similarly to the throttle body  208  in the embodiment of  FIG. 2  or throttle  62  in the embodiment of  FIG. 1 . The noise attenuation device  320  may be used similarly to the noise attenuation device  220  in the embodiment of  FIG. 2  and/or to the noise attenuation device  64  in the embodiment of  FIG. 1 . 
     An axes system  390  is shown comprising three axes, an x-axis parallel to the horizontal axis, a y-axis parallel to the vertical axis, and a z-axis perpendicular to the x and y axes. A rotation axis  395  of a valve  312  of the throttle body is parallel to the x-axis and shown by a large dash line with an arrow R depicting a direction of rotation. A central axis  398  of the noise attenuation device  320  is parallel to the y-axis. The noise attenuation device  320  is symmetric about the central axis  398 , however, the noise attenuation device may be asymmetric without departing from the scope of the present disclosure. Intake air flows parallel to the z-axis through an intake passage  302 . Intake air may contact the throttle body  310  before contacting the noise attenuation device  320 . Thus, solid lines indicate components farther along the z-direction than small dash lines. Large dash lines are bigger than small dash lines. 
     The valve  312  may rotate about the rotation axis  395  (x-axis) in a direction shown by arrow R with a range of motion between 90° to 360°. The valve  312  is shown rotated about the rotation axis  395  in a partially open position with a first end  314  facing an upstream direction and a second end  316  facing a downstream direction with respect to intake air flow. The second end  316  may direct a portion of intake air flow toward the noise attenuation device  320  located on a bottom portion of the intake passage adjacent a change in radiuses (discontinuity) between a first bore  303  of the intake passage  302  and a second bore  304  of the throttle body  310 . In some examples, the valve  312  may rotate in a direction opposite arrow R, in which case, the noise attenuation device  320  may be located in an upper portion of the intake passage  302 . The bores are concentric, wherein the first bore  303  is bigger than the second bore  304  by a distance  380  along an entire circumference of the second bore  304 . The noise attenuation device  320  is directly downstream of the discontinuity created by the change in size (radius) of the bores. The device  320  is physically coupled to a portion of an inner the intake passage  302  via a base  324  (indicated by a thick line). The noise attenuation device  320  comprises a plurality of vanes  322  extending inwardly from the base  324  into the intake passage  302 . The plurality of vanes  322  may be formed of the same material as the base  324 , where both components can be comprised of a plastic and attached together via one or more of glue, an interference fit, or sonic weld. Alternatively, the components may be metal, wherein they may be cast as a single piece or separate pieces. In the case where the vanes  322  and the base  324  are separate pieces, they may be welded together. In some embodiments, the plurality of vanes  322  may be a first set of vanes, where a second set of vanes may be located in an upper portion of the intake passage  302 , opposite the first set. Alternatively, the second set of vanes may be located upstream of the throttle body  310  adjacent an upstream discontinuity. It will be appreciated that a suitable number of sets of vanes may be located in a vehicle system in upstream and downstream positions adjacent discontinuities generated by features of the vehicle system components. 
     The vanes  322  are shown extending inwardly in an axial direction with none of the vanes  322  extending beyond a circumference of the second bore  304  of the throttle body  310 . In this way, a height of the vanes  322  may be staggered wherein outer vanes of the vanes  322  are taller than inner vanes of the vanes  322 . Alternatively, vanes  322  may extend from a predetermined axial position (a position of the base  324  along the y-axis) lower than a lowest portion of the bore  304  and extend radially inward from base  324  for a predetermined distance into intake passage  302 . The predetermined distance is less than or equal to difference  380  between the radiuses of the first bore  303  and the second bore  304 . The vanes  322  may be substantially identical in length and width when extending in the radial direction. The number, shape, length, height, thickness, and orientation of the vanes  322  may be varied based on desired noise dampening characteristics of the noise attenuation device  320 . 
     The vanes  322  are shown extending inwardly along the y-axis for a portion of a circumference of a bottom portion of the intake passage  302 . For example, each of the vanes  322  may extend inwardly 5-10 mm from base  324  and have a thickness of 1-2 mm. Further, vanes  322  may be spaced about an inner circumference of intake passage  302  substantially equidistant from one another. Substantially equidistant may be defined as the distances between the vanes deviating from other distances between the vanes due to production induced intolerances by 2-5% in one example. Alternatively, they may be spaced non-equidistant from one another. The vanes  322  extend the z-axis parallel to the intake flow for some distance. In some examples, the base  324  may span all of the inner circumference with vanes  322  extending radially inward. 
     Referring to  FIGS. 4-7 , several alternate embodiments of noise attenuation devices (noise attenuation device  64  of  FIG. 1  noise attenuation device  220  of  FIG. 2  or noise attenuation device  320  of  FIG. 3 ) or air diffusers are shown. Each embodiment may be disposed downstream of a discontinuity between a throttle body and an intake passage to reduce noise generated therein. The noise attenuation device may be coupled to only a bottom portion of the intake passage, however, the noise attenuation device may be located adjacent other discontinuities of a gas passage without departing from the scope of the present disclosure. Each embodiment may be constructed from steel, high temperature plastic, cast aluminum, dis-cast aluminum, or ceramic, or combinations thereof. Further, the number, shape, axial length, inwardly extending distance, thickness, and orientation of the vanes may be varied based on desired flow characteristics and noise damping characteristics of devices in an intake system. Further, multiple noise attenuation devices may be used in multiple locations intake systems. For example, a noise attenuation device may be places upstream of a discontinuity. 
       FIG. 4  shows a cross-sectional view  400  of a first embodiment of a noise attenuation device  410  spaced away from a throttle body  420  in a downstream direction in a bottom portion of an intake passage  402 . A space  490  between the components may be 1-5 mm. As shown, heights  480 ,  482  of the noise attenuation device and the portion of the throttle body  420  in the intake passage  402  are substantially equal, respectively. Dashed line  412  indicates another embodiment for the noise attenuation device  410 , wherein noise attenuating features (vanes) of the noise attenuation device  410  may be tapered via an angled cut along the dashed line  412  (herein referred to as angled cut  412 ). The angled cut  412  may begin at a top, upstream corner of the device  410  and traverse obliquely downward toward a base  406  of the device. The angled cut  412  may be between a range of 15−75°. In one example, the angled cut is exactly 45°. In this way, vanes may be rectangular, extending along a greater portion of the intake passage  402  than vanes including the angled cut. The device  410  including the angled cut may comprise triangular vanes. 
       FIG. 5  shows a cross-sectional view  500  of a second embodiment of a noise attenuation device  410 . Thus, components previously presented may be similarly numbered in subsequent figures. The second embodiment in the cross-sectional view  500  is identical to the first embodiment in the cross-sectional view  400  of  FIG. 4 , except the second embodiment shows the noise attenuation device being pressed against the throttle body (the space  490  is not present in the second embodiment). In this way, an upstream face  404  of the noise attenuation device is in face-sharing contact with a downstream face  422  of the portion of the throttle body  420  in the intake passage  402  for an entire length of the heights  480  and  482 . The angled cut  412  may begin at an upper upstream corner of the device  410  and end at a corresponding portion of the base  406  based on an angle of the angled cut  412 . 
       FIG. 6  shows a cross-sectional view  600  of a third embodiment of a noise attenuation device  610 . Device  610  is disposed downstream of a portion of a throttle body  620  protruding into an intake passage  602 . Device  610  is in face-sharing contact (pressed against) a downstream face  622  of the throttle body  620  for an entire length of the upstream side  604  before the upstream side begins to angle away from (angled side  608 ) the downstream face  622  of the throttle body  620 . The device  610  has five sides, with upstream  604  and downstream  605  sides normal to a general direction of intake flow, base  606  and top side  607  parallel to the direction of intake flow, and the angled side  608  oblique to intake flow. The device may include an optional angular cut  612  (indicated by a dashed line), which may taper the device  610  from a top of the upstream side  604  and bottom of the angled side  608  to a base  606 . The angled cut  612  may be between 15-75°. The device  610  including the angular cut  612  is tapered and includes four sides, namely the upstream side  604 , the angled side  608 , a tapered side created by the angular cut  612 , and base  606 . 
       FIG. 7  shows a cross-sectional view  700  of a fourth embodiment of a noise attenuation device  710 . Device  710  is disposed downstream of and pressed against a portion of a throttle body  720  protruding into an intake passage  702 . A portion of an upstream side  704  of the device  710  is in face-sharing contact with a downstream side  722  of the throttle body  720  before the upstream side begins to curve away from the throttle body  720 . As shown, upstream side  704  is convex, but it may be concave in other examples. In this way, the device  710  includes three linear sides (downstream side  705 , base  706 , and top side  707 ) with one curved side (upstream side  704 ). An optional curved cut is shown by dashed line  712 , where the cut may begin at an interface between the upstream side  604  and the top side  707 ) and end at the base  706 . As shown, the dashed line  712  is concave, but may be linear or convex in other examples. 
     Thus, the embodiments of  FIGS. 4-7  depict a noise attenuation device with vanes molded onto a base and where the base is coupled to at least a portion of an intake pipe with a throttle body located within the intake pipe. The vanes may be upstream or downstream of the throttle body along a bottom or top portion of an intake passage. 
     In this way, noise emanating from an intake passage may be reduced or prevented without decreasing a power output of an engine. A noise attenuation device may be placed downstream of a change in radius between an intake passage and a throttle body, where the intake passage has a first radius greater than a second radius of the throttle body. The noise attenuation device has a height substantially equal to or less than the change in radius and is at a location where a valve of the throttle body may direct air based on a rotation of the valve corresponding to a change in engine load. The technical effect of placing the device downstream of the discontinuity is to diffuse and/or redirect intake flow such that an impact of intake air hitting an interior surface of the intake passage is reduced. Thus, noise created by intake air flow may be decreased. 
     An intake system comprising a throttle body in an intake passage with a bore having a first radius smaller than a second radius of the intake passage and a noise attenuation device with a plurality of vanes located in the intake passage directly downstream of the throttle body where a height of the vanes is substantially equal to a difference between the radiuses. A first example of the intake system optionally including where the bore and the intake passage are concentric. A second example of the intake system optionally including the first example, and further including the plurality of vanes are spaced about an inner circumference of the intake passage substantially equidistant from one another. A third example of the intake system optionally including one or more of the first and second examples, and further including where the noise attenuation device is physically coupled to an interior surface in a bottom portion of the intake passage. A fourth example of the intake system optionally including one or more of the first through third examples, and further including where the noise attenuation device has a rectangular cross-section. A fifth example of the intake system optionally including one or more of the first through fourth examples, and further including where the noise attenuation device is tapered and has a triangular cross-section. A sixth example of the intake system optionally including one or more of the first through fifth examples, and further including where the plurality of vanes extend inwardly from a base of the noise attenuation device into the intake passage in an axial direction, and where the height of the vanes is greater along an outer portion of the noise attenuation device. A seventh example of the intake system optionally including one or more of the first through sixth examples, and further including where the plurality of vanes extend inwardly from a base of the noise attenuation device into the intake passage in a radial direction, and where the height of each of the vanes is equal and fixed. An eighth example of the intake system optionally including one or more of the first through seventh examples, and further including where the noise attenuation device is spaced away from a portion of the throttle body in the intake passage. A ninth examples of the intake system optionally including one or more of the first through eighth examples, and further including where the noise attenuation device is pressed against a portion of the throttle body in the intake passage. 
     A method of operating an intake system in a passenger vehicle traveling on the road, the method comprising directing an intake flow to an engine of the vehicle via an intake passage, where the passage includes a throttle body with a bore and where a radius of the bore is smaller than a radius of the intake passage and operating a throttle valve of the throttle body to adjust a volume of intake flow in the intake passage, where the vanes protrude inwardly into the intake passage for a predetermined distance equal to a difference in radiuses between the bore and the intake passage. A first example of the method further including where the vanes protrude only partially into the intake passage and do not span across the intake passage. A second example of the method optionally including the first example and further including where the vanes are spaced along an inner circumference of the intake passage equidistant from each other such that the vanes are configured to diffuse intake flow. A third example of the method optionally including the first and/or second examples and further including where the vanes are pressed against or spaced away from the throttle body in upstream and downstream portions of the intake passage. 
     A system comprising a throttle body having a first bore wall with a valve mounted within the first bore, the valve being movable to selectively restrict intake flow, an intake passage having an intake pipe defining a second bore wall and where the second bore has a greater diameter than the first bore, and a noise attenuation device located downstream of the valve and the first bore in the first bore of the intake passage with a plurality of vanes extend inwardly into the second bore for a predetermined distance equal to a difference between the radiuses of the first and second bores. A first example of the system further including where the vanes are molded onto a base and where the base is coupled to at least a portion of the intake pipe. A second example of the system optionally including the first example and further including where the vanes and the base comprise of a similar material. A third example of the system optionally including the first and/or second examples and further including where the vanes are configured to diffuse and redirect intake flow directed toward a lower portion of the intake passage. A fourth example of the system optionally including one or more of the first through third examples, and further including where the vanes are located around a portion of an inner circumference of the second bore. A fifth example of the system optionally including one or more of the first through fourth examples, and further including where the intake passage continues downstream of the throttle body such that an upstream intake passage and a downstream intake passage sandwich the first bore. A sixth example of the system optionally including one or more of the first through fifth examples, and further including where the noise attenuation device comprises only a single set of vanes pressed against or spaced away from the first bore wall. 
     Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the controller in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the engine control system, where the described actions are carried out by executing the instructions in a system including the various engine hardware components in combination with the electronic controller. 
     It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein. 
     The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.