Patent Publication Number: US-11655749-B2

Title: Oxygen sensor cooling duct

Description:
PRIORITY CLAIM 
     This patent application is a continuation of U.S. patent application Ser. No. 16/151,188, entitled “COOLING DUCT,” filed on Oct. 3, 2018, which is a continuation of U.S. patent application Ser. No. 15/873,791, entitled “OXYGEN SENSOR COOLING DUCT,” filed on Jan. 17, 2018, and issued as U.S. Pat. No. 10,119,450 on Nov. 6, 2018, which is a continuation of U.S. patent application Ser. No. 15/418,630, entitled “OXYGEN SENSOR COOLING DUCT,” filed on Jan. 27, 2017, and issued as U.S. Pat. No. 9,909,483 on Mar. 6, 2018, which is a continuation of U.S. patent application Ser. No. 14/475,359, entitled “OXYGEN SENSOR COOLING DUCT,” filed on Sep. 2, 2014, and issued as U.S. Pat. No. 9,587,548 on Mar. 7, 2017, the entirety of each of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The disclosure relates generally to controlling the temperature of vehicle components and specifically to controlling the temperature of vehicle components by ventilating the components with clutch case exhaust air. 
     BACKGROUND OF THE INVENTION 
     Modern vehicles include numerous temperature sensitive devices, such as sensors, switches, microcontrollers, memory devices, communication transceivers, and the like. These devices often include a temperature specification. If operated or exposed to temperatures outside of the temperature specification, the device may not operate or perform reliably. In some cases, the device may even be subject to a shortened lifespan. 
     Modern vehicles also include “hot spots” due to heat sources, such as internal combustion engines and engine exhaust systems. Some of the above devices may be required to be positioned close enough to a “hot spot” to be heated close to or beyond the upper bound of the device&#39;s temperature specification. 
     For example, oxygen sensors are employed in many vehicles to monitor the oxygen content of the vehicle&#39;s engine exhaust. In order to monitor this oxygen content, the oxygen sensor must sample and be exposed to the vehicle&#39;s exhaust. The sensor casing may be mounted directly to the exhaust pipe. The engine exhaust and pipe may be at a greater temperature than the upper bound of the oxygen sensor&#39;s temperature specification. 
     Furthermore, some vehicles are operated in cold climates where the ambient air temperature is less than the lower bound of the temperature specification of various devices. It is for these and other concerns that the following disclosure is offered. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed towards systems, vehicles, and methods for controlling the temperature of temperature sensitive devices or components employed in vehicles. The temperature sensitive device may be either heated or cooled by providing ventilation, where the source of the ventilating air or gas is the vehicle&#39;s drivetrain. 
     A system for cooling a device included in a vehicle includes a drivetrain duct that includes a first aperture and a second aperture. The first aperture is coupled to a drivetrain aperture included in a drivetrain of the vehicle. The system may also include a coupler that is configured and arranged to couple the first aperture to a drivetrain aperture included in a drivetrain of a vehicle such that the second aperture is directed at the device. In at least one embodiment, the second aperture is positioned at a predetermined distance from the device. The device is thermally coupled to a heat source included in the vehicle. 
     When the drivetrain is engaged, the heat source is at a first temperature and the drivetrain outputs drivetrain exhaust gas through the drivetrain aperture. The drivetrain exhaust gas is at a second temperature and at a drivetrain pressure. In some embodiments, the device is under an ambient pressure. The first temperature may be greater than the second temperature. In some embodiments, the drivetrain pressure is greater than the ambient pressure. 
     In some embodiments, the device is an oxygen sensor. The drivetrain aperture may be a transmission aperture. The transmission may be a continuously variable transmission. The heat source includes power source exhaust gas generated by the vehicle&#39;s power source. In at least one embodiment, the heat source includes a power source exhaust duct coupled to the vehicle&#39;s power source. In a preferred embodiment, the drivetrain includes a plurality of rotating fins and/or blades. The plurality of rotating fins and/or blades circulates at least a portion of the drivetrain exhaust through the drivetrain aperture. 
     The drivetrain duct is configured and arranged to be coupled to the vehicle&#39;s frame when the first aperture is coupled to the drivetrain aperture. The device may be a sensor, a switch, or a voltage regulator. 
     The predetermined distance may be based on a difference between the first temperature of the heat source and the second temperature of the drivetrain exhaust gas when the drivetrain is engaged. Furthermore, the predetermined distance may be based on a difference between the ambient pressure that the device is under and the drivetrain pressure of the drivetrain exhaust gas when the drivetrain is engaged. 
     When the drivetrain is engaged, the first temperature of the heat source is between 800° C. and 900° C. This may be the exhaust gas temperature inside a power source exhaust pipe or duct. The second temperature of the drivetrain exhaust gas is between 200° C. and 300° C. A backpressure generated by the drivetrain duct when the drivetrain is engaged is substantially less than a difference between the ambient pressure that the device is under and the drivetrain pressure of the drivetrain exhaust gas. 
     A cross section of the drivetrain duct may be based on at least a difference between the ambient pressure that the device is under and the drivetrain pressure of the drivetrain exhaust gas when the drivetrain is engaged. In at least one embodiment, the system further includes a manifold configured and arranged to position a third aperture of the drivetrain duct at a second predetermined distance from another device when the first aperture is coupled to the drivetrain aperture. 
     A vehicle consistent with the various embodiments includes a frame, a plurality of ground engaging members coupled to the frame, and a power source configured and arranged to convert stored energy into mechanical work. 
     The vehicle also includes a drivetrain configured and arranged to transmit the mechanical work provided by the power source to at least one of the plurality of ground engaging members. The drivetrain includes a first exhaust source that when the drivetrain is engaged produces a first exhaust gas at a first temperature. The first exhaust gas may be at a first pressure. 
     The vehicle also includes a heat source such that when the vehicle is operated, the heat source is at a second temperature that is greater than the first temperature. Further, the vehicle includes a temperature sensitive device that is thermally coupled to the heat source and under an ambient pressure that is less than the first pressure. In at least one embodiment, the vehicle includes a conduit configured and arranged to provide at least a portion of the first exhaust gas to the device. 
     A system for controlling the temperature of a device included in a vehicle includes a drivetrain duct that includes a first aperture and a second aperture. The first aperture is coupled to a drivetrain aperture included in a drivetrain of the vehicle. The system may also include a coupler that is configured and arranged to couple the first aperture to the drivetrain aperture included in the drivetrain of the vehicle such that the second aperture is positioned at a predetermined distance from the device. 
     When the drivetrain is engaged, the device is at a first temperature. The device may be at a first pressure. The drivetrain outputs drivetrain exhaust gas through the drivetrain aperture. The drivetrain exhaust gas is at a second temperature. The drivetrain exhaust may be at a second pressure. The first temperature is different from the second temperature. The second pressure may be greater than the first pressure. In at least one embodiment, the first temperature is less than the second temperature. In another embodiment, the first temperature is greater than the second temperature. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred and alternative examples of the present invention are described in detail below with reference to the following drawings: 
         FIG.  1 A  illustrates an isometric view of an embodiment of a vehicle that is consistent with the various embodiments disclosed herein. 
         FIG.  1 B  illustrates a side view of another embodiment of a vehicle that is consistent with the various embodiments disclosed herein. 
         FIG.  1 C  illustrates an oxygen sensor device configured and arranged to provide data for real time monitoring of the oxygen content in the power source exhaust gas of a vehicle that is consistent with the various embodiments disclosed herein. 
         FIG.  2    illustrates a device, such as the oxygen sensor of  FIG.  1 C , coupled to a power source exhaust duct of a vehicle, such as the vehicle of  FIG.  1 A  or the alternative vehicle of  FIG.  1 B , that is consistent with various embodiments disclosed herein. 
         FIG.  3 A  illustrates a portion of a powertrain that is included in a vehicle that is consistent with the various embodiments disclosed herein. 
         FIG.  3 B  illustrates another embodiment of a Continuously Variable Transmission (CVT) within a CVT cover that has been partially cut-away to reveal various CVT components. 
         FIG.  3 C  illustrates an interior view of a portion of the CVT cover according to various embodiments disclosed herein. 
         FIGS.  3 D- 3 F  illustrates the flow of cooling air through various embodiments of CVTs that are consistent with the various embodiments disclosed herein. 
         FIG.  4    illustrates an isometric side view of a powertrain exhaust duct that is coupled to the powertrain of a vehicle and employed to cool a device included with the vehicle in a cooling method that is consistent with the various embodiments disclosed herein. 
         FIG.  5    illustrates an orthographic top view of a powertrain exhaust duct that is coupled to the powertrain of a vehicle and employed to cool a device included with the vehicle in a cooling method that is consistent with the various embodiments disclosed herein. 
         FIG.  6    illustrates another view of a powertrain exhaust duct that is coupled to the powertrain of a vehicle and employed to cool a device included with the vehicle in a cooling method that is consistent with the various embodiments disclosed herein. 
         FIG.  7    illustrates temperature vs. time series data for the grommet portion of an oxygen sensor, such as the oxygen sensor of  FIG.  1 C , that is thermally coupled to an exhaust system of a vehicle, such as the vehicle of  FIG.  1 A  or the alternative vehicle of  FIG.  1 B . The oxygen sensor was cooled with a method consistent with the various embodiments disclosed herein. 
         FIG.  8    illustrates temperature vs. time series data for the hex portion of an oxygen sensor, such as the oxygen sensor of  FIG.  1 C , that is thermally coupled to an exhaust system of a vehicle, such as the vehicle of  FIG.  1 A  or the alternative vehicle of  FIG.  1 B . The oxygen sensor was cooled with a method consistent with the various embodiments disclosed herein. 
         FIG.  9    illustrates temperature vs. time data for the sensing element/heater portion of an oxygen sensor, such as the oxygen sensor of  FIG.  1 C , that is thermally coupled to an exhaust system of a vehicle, such as the vehicle of  FIG.  1 A  or the alternative vehicle of  FIG.  1 B . The oxygen sensor was cooled with a method consistent with the various embodiments disclosed herein. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as outlined in the claims. 
       FIG.  1 A  illustrates an isometric view of a vehicle  10  that is consistent with embodiments disclosed herein. In some embodiments, vehicle  10  is an off-road sport or utility vehicle. Vehicle  10  includes frame  16 . Vehicle  10  includes a plurality of ground-engaging members  2  coupled to and supported by frame  16 . In some embodiments, ground-engaging members  2  are wheels. 
     Vehicle  10  may include an operator&#39;s seat  6 . In at least one embodiment, vehicle  10  includes a passenger seat  8 . Vehicle  10  may include one or more control mechanisms, such as a steering mechanism  12 , to control vehicle  10 . In various embodiments, vehicle  10  includes a utility bed  22 . Vehicle  10  includes roll-cage  14  to protect at least the operator in the event of a vehicle rollover. Roll-cage  14  may be coupled to frame  16  by employing at least one tube-coupler. 
     In some embodiments, vehicle  10  includes a powertrain that includes a power source and a drivetrain. A power source may include an engine, such as an internal combustion engine, a motor, such as an electric motor, a hybrid engine-motor, or any other device that is configured and arranged to convert stored energy into mechanical work, such as translation or rotation. In a preferred embodiment, the stored energy is stored in the chemical bonds of hydrocarbon molecules. The power source outputs the mechanical work, or power, and makes it available to the drivetrain. The drivetrain is configured and arranged to transmit the power to at least one of the ground engaging members  2 . In at least one embodiment, the powertrain includes transmission  4 . In some embodiments, transmission  4  is a continuously variable transmission (CVT). 
     Vehicle  10  includes one or more air intakes  18 . Air intake  18  provides ambient air to airbox  20  and transmission  4 . Furthermore, to ensure proper operation of the power source, airbox  20  provides a portion of the ambient air from air intake  18  to the power source. In some embodiments, inefficiencies, such as internal friction, cause the transmission  4  to operate at a temperature greater than the ambient temperature. Ambient air provided to transmission  4  by air intake  18  at least partially cools transmission  4  through advection. Because this thermodynamic exchange occurs in the fixed volume of the transmission housing, the heated gas is under a pressure that is greater than the ambient pressure. 
     As discussed in detail in the context of  FIGS.  3 A- 3 F , the operation of transmission  4  induces the venting, circulation, or flow, of this somewhat heated drivetrain cooling air, or simply drivetrain exhaust, through a drivetrain exhaust port. In at least one embodiment, the drivetrain exhaust is transmission exhaust. The drivetrain exhaust port may be a transmission port, such as a CVT air exhaust port. 
     In some embodiments, the conversion of stored energy into mechanical work results in a power source exhaust gas, such as exhaust gas from an internal combustion engine. Due to inefficiencies in the power source&#39;s energy conversion process, the power source exhaust gas, or simply the exhaust, may be at a greater temperature and/or pressure than the ambient air. In a preferred embodiment, the temperature of the power source exhaust is greater than the temperature of the drivetrain exhaust. The pressure of the power source exhaust may be greater than the pressure of the drivetrain exhaust. In a preferred embodiment, the power source exhaust is engine exhaust. 
     As with the transmission exhaust, the pressure differential between the power source exhaust and the ambient air induces the flow of the heated power source exhaust through a power source exhaust port. In a preferred embodiment, the power source exhaust port is coupled to a power source exhaust duct, such as an exhaust pipe. In at least one embodiment, a power source exhaust duct delivers at least a portion of the power source exhaust to at least one of a muffler or catalytic convertor prior to the power source exhaust being vented to the external atmosphere. 
       FIG.  1 B  illustrates a side view of another embodiment of a vehicle  30  that is consistent with the various embodiments disclosed herein. Some features of vehicle  30  may be somewhat or substantially similar, analogous to, or a counterpart of features included in vehicle  10  of  FIG.  1 A . Other features of vehicle  30  may be somewhat or substantially dissimilar, different, alternative to, or not included in vehicle  10 . Likewise, vehicle  10  may include features that are alternative to or have no analog and/or counterpart in vehicle  30 . Both vehicle  10  of  FIG.  1 A  and vehicle  30  of  FIG.  1 B  are consistent with embodiments disclosed herein. Vehicle  10  and vehicle  30  are exemplary vehicles only and the embodiments disclosed herein are not constrained by these exemplary vehicles. 
     Vehicle  30  includes a frame  52 . Vehicle  30  includes a plurality of wheels  42  coupled to and supported by frame  52 . Vehicle  30  includes at least one seating structure  28 . Vehicle  30  includes a steering wheel  32  to control vehicle  30 . Vehicle  30  includes roll-cage  34  to protect one or more occupants of vehicle  30 . Vehicle  30  includes a hood  58  and a utility bed  44 . In at least one embodiment, hood  58  conceals a storage space. 
     Vehicle  30  includes a power source, such as internal combustion engine  50 . Engine  50  exhaust gas may pass through muffler  31  prior to being emitted into the atmosphere. Engine  50  is coupled to a transmission  34 . A rear drive shaft  56  may couple the rear wheels  42  to transmission  34 . A front drive shaft  54  may couple the front wheels  42  to transmission  34 . A shift lever  58  is coupled to transmission  34 . 
       FIG.  1 C  illustrates an oxygen sensor device  100  configured and arranged to provide data for real time monitoring of the oxygen content in the power source exhaust gas of a vehicle, such as vehicle  10  of  FIG.  1 A  or alternative vehicle  30  of  FIG.  1 B , that is consistent with the various embodiments disclosed herein. In at least one embodiment, this data is employed to provide real time monitoring of an air-to-fuel ratio in a power source of the vehicle. 
     Oxygen sensor  100  includes a grommet portion  102 , a hex portion  104 , and a sensing element/heater portion  106 . The hex portion  104  may include a fastener, such as a threaded hex-nut, to couple oxygen sensor  100  to the vehicle. The sensing element/heater portion  106  is exposed to and samples the vehicle&#39;s power source exhaust. Oxygen sensor  100  includes cabling  108 . Cabling  108  is coupled to oxygen sensor  100  proximate the grommet portion  102 . Cabling  108  provides electrical power to the oxygen sensor  100  and is enabled as an input/output (I/O) bus to enable communication with other devices, including outputting the real time oxygen data. 
     In some embodiments, to ensure the fidelity of the oxygen data and the expected lifetime of oxygen sensor  100 , oxygen sensor  100  must be operated within a finite temperature range. In a preferred embodiment, the finite temperature range for sensing element portion  106  is between 600° C. and 950° C. The hex portion  104  must be operated at a temperature less than or equal to 650° C. Likewise, the grommet portion  102  must be operated at a temperature less than 260° C. If oxygen sensor  100  is operated continuously, these maximum values may be lower. 
       FIG.  2    illustrates a device, such as the oxygen sensor  100  of  FIG.  1 C , coupled to a power source exhaust duct of a vehicle, such as the vehicle  10  of  FIG.  1 A  or alternative vehicle  30  of  FIG.  1 B , that is consistent with various embodiments disclosed herein. 
     Exhaust from the power source enters power source exhaust duct  210  through power source exhaust duct input aperture  212 . The heated power source exhaust exits power source exhaust duct  210  through power source exhaust duct output aperture  214 . 
     Oxygen sensor  200  is coupled to power source exhaust duct  210 . In order to sample the oxygen content of the power source exhaust, sensing element (not shown) of oxygen sensor  200  is exposed to power source exhaust through a sensor aperture in power source exhaust duct  210 . In a preferred embodiment, the sensing element protrudes into and is substantially transverse to at least a portion of the lateral cross section of power source exhaust duct  210 . Oxygen sensor  200  may be securely coupled to the power source exhaust duct  210  at the hex portion  204  by a fastener. The fastener may be a hex-nut that threadably engages with corresponding threads included on the sensor aperture. Oxygen sensor  200  includes cabling  208  that is coupled to oxygen sensor  200  at the grommet portion  202 . 
     In at least some embodiments, oxygen sensor  200  is thermally coupled to the heated power source exhaust and/or the power source exhaust duct  210 . Because the sensing element is directly exposed to the power source exhaust, the sensing element is in thermal contact with the power source exhaust gas. Additionally, hex portion  204  may be in direct physical contact with portions of the power source exhaust duct  210 , such as the threaded sensor aperture. Accordingly, hex portion  204  is thermally coupled to the power source exhaust and/or power source exhaust duct  210 . 
     Generally, power source exhaust duct  210  is not substantially thermally insulating. Accordingly, due to the close proximity, grommet portion  202  is also thermally coupled to the power source exhaust and/or power source exhaust duct  210 . Accordingly, during and after operation of the power source, the various portions of oxygen sensor  200  may be at a greater temperature than the ambient air. This increased temperature may interfere with the operability and/or lifetime of oxygen sensor  200 . 
       FIG.  3 A  illustrates a portion of an embodiment of a powertrain that is included in a vehicle that that consistent with the various embodiments disclosed herein. A vehicle, such as vehicle  10  of  FIG.  1 A  may include at least some of the powertrain components illustrated in  FIG.  3 A . Powertrain  300  includes a power source  330 . Power source  330  may be an engine, motor, hybrid engine-motor device, or other such device that converts stored energy into mechanical work. In a preferred embodiment, power source  330  is an internal combustion engine. 
     Power source  330  includes one or more power source exhaust ports  334 . Power source exhaust gas, generated in the power source&#39;s energy conversion process, is expelled through one or more power source exhaust ports  334 . The power source exhaust may be provided to a power source exhaust duct, such as power source exhaust duct  210  of  FIG.  2    (not shown in  FIG.  3 A ). In some embodiments, at least one of the power source exhaust or the power source exhaust duct are at a greater temperature than the ambient air during normal vehicle operation. 
     Powertrain  300  includes a drivetrain. In some embodiments, the drivetrain includes at least a transmission and driveshaft assembly  340 . The transmission may be an automatic, semi-automatic, or a manual transmission. In a preferred embodiment, the transmission includes a continuously variable transmission (CVT). CVT  321  is one exemplary embodiment of a continuously variable transmission. The driveshaft assembly  340  includes at least one drive-member, such as a driveshaft, drive-chain, or a drive-belt. The driveshaft assembly  340  may include a differential. In at least one embodiment, the drivetrain includes a transaxle assembly. 
     CVT  321  is coupled to the power source  330  by crankshaft  332 . CVT  321  includes drive clutch  323  and driven clutch  325 . Drive clutch  323  and driven clutch  325  are coupled by transmission belt  327 . Power from power source  330  is transmitted to drive clutch  323  via crankshaft  332 . In some embodiments, drive clutch  323  rotates at a first frequency based on the rotational frequency of the power source  330 . At least a portion of this rotational energy is transmitted to driven clutch  325  via transmission belt  327 . The driven clutch  325  rotates at a second frequency. 
     The ratio of the first frequency to the second frequency is dependent upon the ratio of the instantaneous running radius of the drive clutch  323  to the radius of the driven clutch  325 . The driven clutch  325  transfers at least a portion of the rotational energy to the driveshaft assembly  340  via input shaft  328 . The driveshaft assembly  340  transfers at least a portion of this rotational energy to at least one of the vehicle&#39;s ground engaging members, such as ground engaging members  2  of  FIG.  1 A . 
       FIG.  3 B  illustrates another embodiment of a continuously variable transmission: CVT  320 . Some features of CVT  320  may be somewhat or substantially similar, analogous, or a counterpart of features included in CVT  321  of  FIG.  3 A . Other features of CVT  320  may be somewhat or substantially dissimilar, different, alternative to, or not included in CVT  320 . Likewise, CVT  321  may include features that are alternative to or have no analog and/or counterpart in CVT  320 . Both CVT  320  and CVT  321  are consistent with embodiments disclosed herein. CVT  320  and CVT  321  are exemplary transmissions only and the embodiments disclosed herein are not constrained by these exemplary transmissions. 
     CVT  320  is housed within CVT cover  342  that has been partially cut-away to reveal various CVT components. The CVT  320  has a driven clutch  324 , a drive clutch  322 , and a transmission belt  326  between the driven clutch  324  and the drive clutch  322 . The drive clutch  322  is coupled to a power-source crankshaft, such as power-source crankshaft  332  of  FIG.  3 A . Drive clutch  322  receives power from a power source, such as power source  330  of  FIG.  3 A . Drive clutch  322  transmits this power through the transmission belt  326  to the driven clutch  324 , and eventually from the driven clutch  324  to the vehicle&#39;s ground engaging members. 
     The drive clutch  322  can have two conical sheaves  336  holding the transmission belt  326  between them. Moving the sheaves  336  toward and away from one another changes the effective gear ratio of the drive and driven clutch system. As the sheaves  336  of the drive clutch  322  move farther apart the belt drops to a lower location on the sheaves  336  and to a higher location on the sheaves of the driven clutch  324 . Conversely, as the drive sheaves  336  move closer together, the driven sheaves mover farther apart. Thus, the gear ratios from input to output smoothly change, thereby achieving a continuously variable transmission. Although, all the movement of the belt sides along the sides of the sheaves as the clutches are turning creates heat. Aspects of the present invention can also be used with other transmissions and with other engine casing components. 
     The backside (first portion  338 ) of CVT cover  342  surrounds the side of the CVT  320  adjacent the power source and transmission. CVT cover  342  protects the moving parts of CVT  320 . CVT cover  342  also serves as a channel through which air moves to cool various CVT components, such as drive sheaves  336 , driven clutch  324 , and transmission belt  326 . The cover includes a transmission air inlet  316  near the drive clutch  322  and a transmission air outlet  318  near the driven clutch  324 . The positions of the transmission air inlet  316  and transmission outlet  318  can vary slightly, but preferably the transmission air inlet  316  and transmission air outlet  318  are on substantially opposing sides of CVT cover  342  to permit the air to flow over the components of the CVT  320  and out the other side. 
     CVT cover  342  is formed of two portions: a first portion  338 , and a second portion  344 . The two portions  338 ,  344  are split along a line parallel with transmission belt  326 . The two portions are held together by bolts through bosses  346  around the periphery of CVT cover  342 . The bosses are preferably on the external portion of the CVT cover  342  to allow smoother airflow in the interior of CVT cover  342  for better cooling. 
     The first portion  338  can be on the power source side and the second portion  344  can be on the wheel side, or vice versa. In the illustrated embodiment of  FIG.  3 B , the first portion  338 , in which the transmission air inlet  316  and transmission air outlet  318  are formed, are both on the engine side of CVT  320 . Depending on the configuration of CVT  320  and the power source, the heat builds up more significantly on the power source side of CVT  320 . However, in a different configuration, the heat may be more concentrated elsewhere, in which cover the transmission air inlet  316  and transmission air outlet  318  can be positioned accordingly. 
     As noted above, inefficiencies create heat, such as the movement of transmission belt  326  along the drive clutch  322  and driven clutch  324 . In order to cool the transmission components, such as transmission belt  326 , driven clutch  324 , and drive clutch  322 , ambient air flows from a vehicle air intake, such as air intake  18  of  FIG.  1 A , and into CVT cover  342  through transmission air inlet  316 . As the ambient air flows through the volume surrounding CVT  320 , the various CVT components are cooled. 
     Heat exchanged between this ambient air and CVT  320  produces heated drivetrain exhaust, such as heated transmission exhaust. The transmission exhaust is at a greater temperature and pressure than the ambient air. The drivetrain exhaust is expelled from the CVT cover  342  through transmission air outlet  318 . In at least one embodiment, transmission air outlet  318  is a drivetrain exhaust port. In at least one embodiment, the drivetrain exhaust is expelled through the drivetrain exhaust port at least partially due to the increased pressure of the heated air within the drivetrain housing. As shown in  FIG.  3 B , the fins on the drive clutch and the driven clutch also function as a pump to expel the drivetrain exhaust. 
       FIG.  3 C  illustrates an interior view of a portion of CVT cover  342  according to various embodiments disclosed herein. CVT cover  342  includes first portion  338 . First portion  338  of CVT cover  342  includes various features and surfaces that enhance the airflow of cooling ambient air received by the transmission air inlet  318  and the drivetrain exhaust expelled through transmission air outlet  318  or drivetrain exhaust port. In some embodiments, a second portion (not shown in  FIG.  3 C ) may also include similar airflow-enhancing features and/or surfaces. As the fins or blades included on the drive and driven clutches pump air in through air inlet  316  and out air outlet  318 , these features and/or surfaces guide or channel the flow of air that cools the transmission components. 
       FIGS.  3 D- 3 F  illustrates the flow of cooling air through various embodiments of CVTs that are consistent with the various embodiments disclosed herein. Note that the flow of air through the CVT casing is dependent upon various features included in the CVT cover  342 . 
     In preferred embodiments, as the drivetrain exhaust exits CVT cover  342  through transmission air outlet  318 , the power source exhaust is at a substantially greater temperature than the drivetrain exhaust. Thus, relative to the power source exhaust, the drivetrain exhaust is cooling exhaust or air. In at least one embodiment, the power source exhaust is approximately 900° C. under normal vehicle operating conditions. The powertrain exhaust may be between 200° C. and 300° C. under normal vehicle operating conditions 
     In some embodiments, a device such as a sensor or a switch is thermally coupled to the power source exhaust, such as oxygen sensor  200  in  FIG.  2   . The device may malfunction, operate unreliably, experience a decreased lifetime, catastrophically fail, or otherwise cease to function once heated beyond a critical temperature. Due to the substantial temperature of the power source exhaust, the device may be heated close to or beyond this critical temperature during normal vehicle operating conditions. In some embodiments, the temperature differential between the power source exhaust and the drivetrain exhaust, as well as the pressure differential between the drivetrain exhaust and the ambient air is employed to cool the device to a temperature within an acceptable temperature window. 
       FIG.  4    illustrates an isometric side view of a drivetrain exhaust duct that is coupled to the drivetrain of a vehicle. The cooler drivetrain exhaust is employed to cool a device included with the vehicle in a cooling method that is consistent with the various embodiments disclosed herein. The drivetrain may be included in a vehicle, such as vehicle  10  of  FIG.  1 A . The drivetrain may include various components, including but not limited to a transmission, such as CVT  321  of  FIG.  3 A  or CVT  320  of  FIG.  3 B . 
     In a preferred embodiment, device  400  is an oxygen sensor, such as oxygen sensor  100  of  FIG.  1 C . Although other embodiments are not so constrained, and device  400  may include any other sensor, switch, integrated circuit (IC), semiconductor component, or any other device included in a vehicle. Device  400  may be a component. Device  400  is coupled to power source exhaust duct  410 , in a similar manner to that described in the discussion of  FIG.  2    and in regards to coupling oxygen sensor  200  to power source exhaust duct  210 . As also discussed in regards to  FIG.  2   , device  400  is thermally coupled to the power source exhaust and or power source exhaust duct  410 . Device  400  may include a sensing element portion (not shown) that is exposed to the power source exhaust gas. Device  400  may include a hex portion  404 , a grommet portion  402 , and cabling  408 . 
     In some embodiments, a power source exhaust manifold  416  is employed to couple power source exhaust duct  410  to the vehicle&#39;s power source (not shown). Power source exhaust duct  410  may be coupled to power source exhaust manifold  416  at the power source exhaust duct input aperture  412 . The vehicle&#39;s power source is similarly situated as power source  330  of  FIG.  3 A . In various embodiments, other auxiliary power source exhaust ducts  434  are intermediate the power source exhaust manifold  416  and power source exhaust ports, such as exhaust ports  334  of  FIG.  3 A . In at least one embodiment, power source exhaust enters the power source exhaust duct  410  through power source exhaust duct input aperture  412 . 
     Power source exhaust duct  410  may be coupled to vehicle muffler  460  at power source exhaust duct output aperture  414 . Power source exhaust gas flows from power source exhaust duct  410  to muffler  460  via power source exhaust output aperture  414 . In some embodiments, at least a portion of the power source exhaust gas is provided to a catalytic converter by the power source exhaust duct  410 . Because of the substantial temperature of the power source exhaust gas, the power source exhaust duct  410  may be at a temperature significantly greater than that of the ambient air during or after normal operation of the power source. 
     In some embodiments, a drivetrain exhaust duct  450  is employed to provide drivetrain exhaust gas to a volume proximate the device  400 . Drivetrain exhaust duct  450  may be an exhaust pipe. Drivetrain exhaust duct  450  may be a conduit. Drivetrain exhaust duct  450  may be constructed from metal, plastic, or any material that can withstand the elevated temperatures of drivetrain exhaust and be in close proximity to power source exhaust duct  410 . 
     In some embodiments, drivetrain exhaust gas may be transmission exhaust gas. Drivetrain exhaust duct  450  may be coupled to a drivetrain component. In a preferred embodiment, drivetrain exhaust duct  450  is coupled to a transmission  420  included in the vehicle&#39;s drivetrain. In at least one embodiment, drivetrain exhaust duct  450  is coupled, either directly or indirectly, to a transmission air outlet, such as transmission air outlet  318  of  FIGS.  3 B and  3 C . The transmission may be an automatic transmission, a semi-automatic transmission, or a manual transmission. Transmission  420  may be a CVT, such as CVT  321  of  FIG.  3 A  or CVT  320  of  FIG.  3 B . In at least one embodiment, drivetrain exhaust duct  450  is coupled to a torque converter. 
     Transmission  420  is housed in a transmission housing that includes transmission cover  442 . A drivetrain exhaust manifold  444  may be employed to couple drivetrain exhaust duct  450  to a drivetrain exhaust port included in transmission  420 . Drivetrain exhaust manifold  444  may be a coupler. For instance, drivetrain exhaust manifold may be positioned between a transmission air outlet and the drivetrain exhaust duct  450 . Drivetrain exhaust manifold  444  may be coupled to transmission  420  by employing a fastener, such as a hose-clamp. 
     In some embodiments, drivetrain exhaust duct  450  may include a frame-mounting bracket  454 . Frame mount bracket  454  may be employed to secure and/or stabilize drivetrain exhaust duct  450  to the vehicle&#39;s frame, such as frame  16  of  FIG.  1 A . Drivetrain exhaust duct  450  may be coupled to the vehicle frame by employing any suitable fastener, such as bolts or the like. In at least one embodiment, a cable tie is employed to couple the drivetrain exhaust duct  450  to the frame, through an aperture in frame mounting bracket  454 . A cable tie may be a Zip-Tie®. 
     Drivetrain exhaust gas (i.e., cooling air) is delivered to a volume that is proximate to device  400  through drivetrain exhaust duct output aperture  452 . In preferred embodiments, the temperature of the transmission exhaust gas is less than the temperature of the power source exhaust gas and the temperature of power source exhaust duct  410 . Because device  400  is thermally coupled to the power source exhaust gas and power source exhaust duct  410 , at least portions of device  400  are at temperatures that exceed the temperature of drivetrain exhaust gas. The drivetrain exhaust gas that is delivered to the volume that is proximate to device  400  provides ventilation and cools device  400  through advection. 
     In some embodiments, the drivetrain exhaust gas includes air that was provided to transmission  420  through a vehicle air intake, such as air intake  18  of  FIG.  1   . This air is somewhat heated within the transmission housing, but not nearly to the same degree as the power source exhaust gas. As described in the context of  FIGS.  3 B- 3 F , air is circulated through the transmission housing with the assistance of fins or blades included on various rotating components of the transmission, such as drive and/or driven clutches. In preferred embodiments, structures and/or surfaces within the transmission housing provide additional assistance in the airflow through and out of the transmission casing. As the air flows across the transmission components, the air cools the components. This heat exchange heats the air. The pumping action of the fins and/or blades of the rotating transmission components, along with structures and/or surfaces internal to the transmission housing, pumps the drivetrain exhaust out of a transmission air outlet and through the drivetrain exhaust duct  450 . In at least one embodiment, additional mechanical means, such as a fan or a pump, are employed to provide additional assist in the flow or circulation of drivetrain exhaust to the device  400   
     Drivetrain exhaust within the transmission housing is at a first temperature and a first pressure. In some embodiments, the first temperature may be between 200° C. and 300° C. The portion of the drivetrain exhaust gas that is provided to the volume that is proximate to device  400  via drivetrain exhaust duct  450  is at another temperature and another pressure. The other pressure is less than the first pressure. In some embodiments, depending on the ambient temperature and the thermal insulating properties of drivetrain exhaust duct  450 , the other temperature is less than the first temperature due to cooling of the drivetrain exhaust during travel through drivetrain exhaust duct  450 . 
     The difference between the first pressure and the other pressure is the pressure drop across the drivetrain exhaust duct  450 . This pressure drop may provide additional pumping action to circulate the drivetrain exhaust during travel through drivetrain exhaust duct  450 . In some embodiments, drivetrain exhaust duct  450  is configured and arranged to minimize, or at least decrease, this pressure drop. The drivetrain exhaust flow rate and the pressure drop across drivetrain exhaust duct  450  depend upon various factors, including but not limited to the various rotational frequencies of the transmission components, the arrangement and configuration of any blades and/or fins included with any rotating transmission components, structures or surfaces internal to the transmission housing, the first pressure, the first temperature, the ambient air temperature, the pressure, and the inclusion of any additional mechanical means such as fans and/or air pumps. 
     The drivetrain exhaust flow rate and the pressure drop across drivetrain exhaust duct  450  also depend upon various physical characteristics of the drivetrain exhaust duct  450  and the drivetrain exhaust manifold  444 . These features include but are not limited to the duct and/or manifold&#39;s lateral cross section, total path length that exhaust gas must travel, bends or other features that may induce backpressure, total vertical distance that exhaust gas must travel, and other geometrical considerations. In certain embodiments, any of these features may be varied to suit the cooling needs of device  400 . 
     The capability to cool device  400  depends upon the flow rate of drivetrain exhaust gas from drivetrain exhaust duct output aperture  452 , the temperature of the drivetrain exhaust at the drivetrain exhaust duct output aperture  452 , the temperature of the various portions of device  400 , the temperature of the power source exhaust, the temperature of the power source exhaust duct  410 , the lateral cross section of the drivetrain exhaust duct output aperture  452 , distance between drivetrain exhaust output aperture  452  and the various portions of device  400 , the speed of the vehicle, the ambient air temperature, and other such factors. 
     In some embodiments the shape, geometry, and/or position of the drivetrain exhaust duct  450  and/or drivetrain exhaust manifold  444  may be based on the cooling requirements for device  400 , and other factors. These other factors include, but are not limited to the temperature differential between the power source exhaust and the drivetrain exhaust, the pressure differential between the drivetrain exhaust and the ambient air, the power to be transmitted to the vehicle&#39;s ground engaging members, the expected operating conditions, such as engine load, terrain to be traversed, and climate, of the vehicle. In at least one embodiment, drivetrain exhaust output aperture  452  is positioned closer to device  400  for enhanced cooling capability. 
     In at least one embodiment, a duct-extender may be coupled to drivetrain output aperture  452  to decrease the distance between the location of drivetrain exhaust duct&#39;s  410  output and device  400 . The lateral cross section of the duct-extender may be varied to increase or decrease the lateral cross section of the drivetrain&#39;s output. In at least one embodiment, the duct-extender may provide a fan-out or output manifold structure to deliver drivetrain exhaust to a plurality of locations and/or volumes to cool other devices. 
     Although device  400  is coupled to the power source exhaust duct  410 , other embodiments are not so constrained. Device  400  may be located at other vehicles locations and may be at a temperature greater than that of the drivetrain exhaust. The shape, orientation, and location of drivetrain exhaust duct  450  may be varied to provide cooling drivetrain exhaust to other regions of the vehicle. In addition to an oxygen sensor, device  400  may include device types, such as but not limited to voltage regulators, gear selector switches, power distribution modules, engine control units, coolant temperature sensors, microcontrollers, processor devices, digital memory devices, field programmable gate arrays (FPGAs), accelerometers, communication transceivers, or any other component that may, due to its proximity to heating sources on the vehicle, may reach temperatures greater than that of the drivetrain exhaust gas. In some embodiments, device  400  is heated at least partially because device  400  is itself a heat source. Such heat source device types may include, but are not limited to integrated circuits that generate electrical current and/or mechanical components that generate friction. In at least one embodiment, drivetrain exhaust duct  450  may be configured and arranged to provide drivetrain exhaust to a plurality of devices that are positioned at disparate locations via a fan-out or manifold structure. 
     In alternative embodiments, some vehicles may be configured and arranged to operate in cold climates, such as arctic regions or high altitude locations. Some devices included in the vehicle may include temperature specifications with a lower temperature bound that is greater than the ambient temperature of the expected climate of operation. In such situations, the transmission exhaust duct  450  may be employed to heat such devices by providing the warmer drivetrain exhaust gas to the device of vehicle region to be warmed. 
       FIG.  5    illustrates an orthographic top view of a powertrain exhaust duct that is coupled to the powertrain of a vehicle and employed to cool a device included with the vehicle in a cooling method that is consistent with the various embodiments disclosed herein. The embodiment illustrated in  FIG.  5    includes similar features to the embodiments illustrated in  FIG.  4   . 
     Power source exhaust may flow from the vehicle&#39;s power source (not shown) to muffler  560 , through auxiliary power source exhaust ducts  534 , then through power source exhaust manifold  516 , and into power source exhaust duct  510 . Power source exhaust gas may enter power source exhaust duct  510  through power source exhaust duct input aperture  512  and exit through power source exhaust duct output aperture  514 . 
     Device  500  is thermally coupled to power source exhaust gas and/or power source exhaust duct  510 . Device  500  may include a sensing element portion (not shown). Device  500  includes a hex portion  504 , a grommet portion  502 , and cabling  508 . 
     Device  500  is cooled through advection by drivetrain exhaust air provided to device  500  via a drivetrain exhaust duct  550 . Drivetrain exhaust duct  550  is coupled to the vehicle&#39;s drivetrain through drivetrain exhaust manifold  544 . The source of the drivetrain exhaust may be a transmission, such as a CVT. The transmission exhaust gas is delivered to a volume that is proximate to device  500  through drivetrain exhaust duct output aperture  552 . In some embodiments, drivetrain exhaust duct  510  is coupled to the vehicles frame via frame mounting bracket  554 . 
       FIG.  6    illustrates another view of a powertrain exhaust duct that is coupled to the powertrain of a vehicle and employed to cool a device included with the vehicle in a cooling method that is consistent with the various embodiments disclosed herein. The embodiment illustrated in  FIG.  6    includes similar features to the embodiments illustrated in  FIG.  4    and  FIG.  5   . 
     Power source exhaust may flow through power source exhaust duct  610 . Power source exhaust gas may enter power source exhaust duct  610  and exit out through power source exhaust duct output aperture  614 . 
     Device  600  is thermally coupled to power source exhaust gas and/or power source exhaust duct  610 . Device  600  may include a sensing element portion (not shown). Device  600  includes a hex portion  604 , a grommet portion  602 , and cabling  608 . 
     Device  600  is cooled through advection by drivetrain exhaust air provided to device  600  via a drivetrain exhaust duct  650 . Drivetrain exhaust duct  650  is coupled to the vehicle&#39;s drivetrain through drivetrain exhaust manifold  644 . The source of the drivetrain exhaust may be a transmission, such as a CVT  620 . The transmission exhaust gas is delivered to a volume that is proximate to device  600  through drivetrain exhaust duct output aperture  652 . In some embodiments, drivetrain exhaust duct  610  is coupled to the vehicles frame via frame mounting bracket  654 . 
       FIG.  7    illustrates temperature time series data for the grommet portion of an oxygen sensor, such as the oxygen sensor  100  of  FIG.  1 C , that is thermally coupled to an exhaust system of a vehicle, such as vehicle  10  of  FIG.  1 A  or alternative vehicle of  FIG.  1 B . The oxygen sensor was cooled with a method consistent with the various embodiments disclosed herein. Temperature data was acquired for 17 continuous minutes. The x-axis of the plot represents time in minutes and the y-axis of the plot represents temperature in degrees centigrade. 
     During the test sequence, the vehicle was toggled between an idle state, a ground-speed state, and an off state. During an idle state, the vehicle&#39;s engine was idling and the vehicle was not moving. During the idle state, engine exhaust is generated (but at an idle or low engine speed). The exhaust gas heats the oxygen sensor. Because the vehicle is not moving, the transmission is not transmitting power to the wheels. Accordingly, there is very little, if any, transmission exhaust providing ventilation to the oxygen sensor during the idle state. 
     During the ground-speed state, both the engine speed and the ground speed are increased. Accordingly, the oxygen sensor is simultaneously heated by the engine exhaust and, during some of the tests, cooled by the transmission exhaust during the ground-speed state. During the off state, the engine is turned off. Accordingly, the oxygen sensor is not being heated by engine exhaust and is not being ventilated by the transmission exhaust. During the off state, the oxygen sensor is being cooled by the ambient air and heat diffusion. The test sequence during data acquisition was as follows, where t is the x-axis value: idle state for 0≤t&lt;1 min, ground-speed state for 1≤t&lt;6 min, idle state for 6≤t&lt;7 min, ground-speed state for 7≤t&lt;12 min, off state for 12≤t&lt;17 min. 
     Curve  770  illustrates the grommet portion temperature, as a function of time during the above test sequence, for an “original pipe” configuration. Herein, the “original pipe” refers to a configuration where the oxygen sensor was housed within heat shields to protect the various components from engine exhaust heat, rather than being cooled with transmission exhaust during the ground-speed states of the test. The oxygen sensor was located mid-way through the exhaust stream and housed within the set of heat shields. The heat shields decreased ambient airflow to the oxygen sensor. The temperature of the grommet portion of the oxygen sensor, at t=0 mins for curve  770 , as well as the other curves presented in  FIGS.  7 ,  8  and  9   , is greater than the ambient air temperature because the oxygen sensor was already warm due to previous testing. 
     Curve  780  illustrates the grommet portion temperature, as a function of time during the above test sequence, for a “new pipe” configuration. Herein, the “new pipe” configuration refers to a configuration where the oxygen sensor was moved downstream along the exhaust system, but not cooled with transmission exhaust during the ground-speed states of the test. 
     Curve  790  illustrates the grommet portion temperature, as a function of time during the above test sequence, for a “new pipe and transmission exhaust duct” configuration. Herein, the “new pipe and transmission exhaust duct” configuration refers to placing the oxygen sensor downstream as discussed above and cooling the oxygen sensor with transmission exhaust during the ground-speed states of the test 
     As shown by curves  770 ,  780 , and  790 , cooling the oxygen sensor with transmission exhaust results in significant decreases in temperature of the grommet portion of the oxygen sensor. At t=0 mins, the temperature of curve  790  is significantly greater than that of curve  780  (due to different previous testing conditions). However, within approximately 1 minute of being cooled with exhaust gas (at t˜2 mins), curve  790  is cooled to a temperature less than the curve  780  (not being cooled by transmission exhaust). 
       FIG.  8    illustrates temperature time series data for the hex portion of an oxygen sensor, such as the oxygen sensor  100  of  FIG.  1 C , that is thermally coupled to an exhaust system of a vehicle, such as vehicle  10  of  FIG.  1 A  or alternative vehicle  30  of  FIG.  1 B . The oxygen sensor was cooled with a method consistent with the various embodiments disclosed herein. Temperature data was acquired for 17 continuous minutes during the test sequence described above. The x-axis of the plot represents time in minutes and the y-axis of the plot represents temperature in degrees centigrade. 
     Curve  870  illustrates the hex portion temperature, as a function of time during the above test sequence, for the “original pipe” configuration. Curve  880  illustrates the hex portion temperature, as a function of time during the above test sequence, for the “new pipe” configuration. Curve  890  illustrates the hex portion temperature, as a function of time during the above test sequence, for the “new pipe and transmission exhaust duct” configuration. 
       FIG.  9    illustrates temperature time series data for the sensing element portion of an oxygen sensor, such as the oxygen sensor  100  of  FIG.  1 C , that is thermally coupled to an exhaust system of a vehicle, such as vehicle  10  of  FIG.  1 A  or alternative vehicle  30  of  FIG.  1 B . The oxygen sensor was cooled with a method consistent with the various embodiments disclosed herein. Temperature data was acquired for 17 continuous minutes during the test sequence described above. The x-axis of the plot represents time in minutes and the y-axis of the plot represents temperature in degrees centigrade. 
     Curve  970  illustrates the sensing element portion temperature, as a function of time during the above test sequence, for the “original pipe” configuration. Curve  980  illustrates the sensing element portion temperature, as a function of time during the above test sequence, for the “new pipe” configuration. Curve  990  illustrates the sensing element portion temperature, as a function of time during the above test sequence, for the “new pipe and transmission exhaust duct” configuration. As shown in  FIG.  2   , the sensing element of the oxygen sensor is embedded within the engine&#39;s exhaust duct  210 . Thus, the transmission exhaust is not directly incident on the sensing portion. Accordingly, the cooling due to transmission exhaust is less significant for the sensing portion, as compared to other portions of the oxygen sensor that are directly exposed to transmission exhaust. 
     All of the embodiments and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.