Abstract:
An apparatus for simulating the sound of a conventionally powered gasoline or diesel powered engine in an electrically powered passenger vehicle having an electric drive motor operatively coupled to one or more of the vehicle&#39;s wheels for rotating the vehicle&#39;s wheels to propel the vehicle, includes a rotary air mover and sound generator for supplying cooling air to the electric drive motor and for generating a variable sound having at least one variable sound parameter, a motor for driving the rotary air mover and sound generator; and a controller for controlling the rotary air mover and sound generator, the controller controlling the rotary air mover and sound generator to change the variable parameter of sound generated by the rotary air mover and sound generator such that the sound parameter of sound generated by the rotary air mover and sound generator matches a selected one of the vehicle&#39;s performance parameters.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a non-provisional patent application of U.S. Provisional Application for Patent Serial No. 61/052,510, filed May 12, 2008, and entitled ELECTRICALLY PROPELLED VEHICLE HAVING ELECTRIC SOUND-PRODUCING BLOWER/COOLER, the specification of which is incorporated herein in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The following disclosure relates to electrically powered vehicles and in particular, an electrically powered vehicle having a rotating blower/cooler for providing an engine or turbine-like sound while supplying cooling air to the electrically powered components of a vehicle. 
       BACKGROUND 
       [0003]    A combination of factors including ever-increasing energy costs, environmental concerns and the development of new battery technology has revived interest in electrically powered automobiles. Currently, electric cars using “plug-in” technology are available that have a driving range of 200 or more miles per day and performance rivaling or exceeding conventional vehicles powered with gasoline or diesel fuels. Hybrid vehicles using a combination of an electric drive with a conventional gas or diesel engine are also receiving more attention. One characteristic of plug-in electrically powered vehicles is that the vehicles generate little or no engine sound. Similarly, hybrid electric vehicle produce little or no sound when operated in the electric mode. 
         [0004]    However, drivers (and pedestrians) are familiar with the sound generated by conventional automobiles. The sound generated by a gasoline or diesel powered engine is appealing to a large number of drivers and consumers that equate the engine sound with power and performance. Further, the sound generated by the engines of conventional diesel and gasoline powered vehicles often alerts pedestrians, pets and wild animals to the approach of the vehicle. 
         [0005]    Electrically powered automobiles utilizing both plug-in and hybrid technology require large battery packs, powerful electric motors and motor controllers to provide satisfactory performance. Such battery packs, motors and controllers generate a substantial amount of heat that must be dissipated to avoid damage. Thus, there exists a need for an electrically powered automobile having a combination air mover and sound generator that provides audible simulation while providing sufficient cooling to the vehicle&#39;s electrical components. 
       SUMMARY 
       [0006]    According to the disclosure, an electrically powered vehicle includes an electric drive motor operatively coupled to one or more of the vehicle&#39;s wheels for rotating the vehicle&#39;s wheels to propel the vehicle. The electric drive motor is powered with a battery or battery pack or for supplying power to the electric drive motor that is controlled with a motor controller. In one aspect a rotary air mover and sound generator having an air inlet and air outlet provides cooling air to the electric drive motor while generating a sound having at least one variable parameter as the vehicle moves. The rotary air mover and sound generator is driven with a blower motor and controlled with a speed controller that varies the speed of the rotary air mover and sound generator to vary the variable parameter of the sound generated by the rotary air mover and sound generator so that the parameter of sound generated by the rotary air mover and sound generator change with one of the vehicle&#39;s parameters. The vehicle performance parameter may be one of the vehicle&#39;s speed, acceleration, deceleration, throttle position and the speed of the vehicle&#39;s drive motor. The variable sound parameters may include volume, frequency, constant tone, variable tone and interrupted tone. In one embodiment, the rotary air mover and sound generator is one of an axial fan or a centrifugal blower. In another aspect, a resonating chamber is connected to the outlet of the rotary air mover and sound generator. 
         [0007]    In another aspect, an apparatus for simulating the sound of a conventionally powered gasoline or diesel powered engine in an electrically powered passenger vehicle having an electric drive motor operatively coupled to one or more of the vehicle&#39;s wheels for rotating the vehicle&#39;s wheels to propel the vehicle includes a rotary air mover and sound generator mounted on the vehicle. The apparatus is configured to supply cooling air to the electric drive motor and to generate a variable sound having at least one variable sound parameter. A motor is provided for driving the rotary air mover and sound generator along with a controller for controlling the rotary air mover and sound generator. In one embodiment, the controller controls the rotary air mover and sound generator to change the variable parameter of sound generated by the rotary air mover and sound generator such that the sound parameter of sound generated by the rotary air mover and sound generator matches a selected one of the vehicle&#39;s performance parameters. The variable parameter of sound may be frequency, volume, tone or pitch. 
         [0008]    In one variation, the controller controls the rotary air mover and sound generator such that a sound parameter of the sound generated by the rotary air mover and sound generator varies linearly with one of the speed or acceleration of the vehicle. In another embodiment, the controller controls the rotary air mover and sound generator such that a sound parameter of the sound generated by the rotary air mover and sound generator varies non-linearly with one of the speed or acceleration of the vehicle. 
         [0009]    In another aspect, the rotary air mover and sound generator comprises an axial fan having adjustable pitch blades and wherein the sound parameter is varied by changing the pitch of the blades of the axial fan or varying the distance between the blades of the fan and/or the distance between the blades and the outlet cut-off. The sound parameter may also be varied by changing the speed of the axial fan in response to a change in the speed of the vehicle or the acceleration of the vehicle. In another variation, the rotary air mover and sound generator comprises a centrifugal blower and wherein the sound parameter is varied by changing the speed of the blower. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0010]    For a more complete understanding, reference is now made to the following description taken in conjunction with the accompanying Drawings in which: 
           [0011]      FIG. 1  illustrates an electrically driven vehicle employing a the combination air mover and sound generator according to the disclosure; 
           [0012]      FIG. 2  is a graph illustrating the relationship between motor or vehicle speed and the volume of sound generated by the combination air mover and sound generator of  FIG. 1  in one embodiment; 
           [0013]      FIG. 3  is a graph illustrating the relationship between vehicle acceleration/deceleration and the volume of sound generated by the combination air mover and sound generator of  FIG. 1  in one embodiment; 
           [0014]      FIG. 4  is a graph illustrating the relationship between vehicle speed or motor speed and the pitch or frequency of sound generated by the combination air mover and sound generator of  FIG. 1  in one embodiment; 
           [0015]      FIG. 5  is a graph illustrating a simulated shifting sound generated by the combination air mover and sound generator of  FIG. 1 ; 
           [0016]      FIG. 6  is a graph illustrating a pulsed or interrupted tone or volume generated by the combination air mover and sound generator of  FIG. 1 ; 
           [0017]      FIG. 7  illustrates an electrically driven vehicle employing an alternate configuration of the combination air mover and sound generator according to the disclosure; and 
           [0018]      FIG. 8  illustrates an electrically driven vehicle wherein the air mover and sound generator is mounted on the exterior of the vehicle. 
       
    
    
     DETAILED DESCRIPTION  
       [0019]    Referring now to the drawings, wherein like reference numbers are used herein to designate like elements throughout, the various views and embodiments of electrically propelled vehicle having electric sound-producing blower/cooler are illustrated and described, and other possible embodiments are described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated and/or simplified in places for illustrative purposes only. One of ordinary skill in the art will appreciate the many possible applications and variations based on the following examples of possible embodiments. 
         [0020]    Referring to  FIG. 1 , in one embodiment an electrically powered vehicle  100  includes a battery or battery pack  102 , an electric drive motor  104  and a motor controller package  106 . As used herein, an “electrically powered vehicle” or “electrically driven vehicle” includes plug-in and hybrid vehicles capable of transporting human passengers and having one or more electric motors that supply rotary power to the vehicle&#39;s wheels to propel the vehicle. As illustrated, an electric drive motor  104  is mounted at the rear  108  of the vehicle with battery pack  102  and motor controller  106  mounted in a compartment  110  above the electric motor. In other variations, battery pack  102 , motor  104  and controller package  106  may be mounted at alternative positions in the vehicle, for example in the front of the vehicle or in a mid-body motor configuration or at different locations in the vehicle. Motor controller  106  is connected to operator controls (not shown) for energizing the drive motor and controlling the speed of the motor and vehicle. 
         [0021]    Referring still to  FIG. 1 , a rotary blower and sound generator  112  is mounted in a compartment  114  at the front  116  of the vehicle. In one embodiment, blower  112  is selected to generate sounds that simulate the noise generated by a high-speed turbine or a high performance conventionally fueled engine operating at high revolutions per minute (rpm). Vehicle  100  may include an access door  118 , similar to the hood of a conventional gasoline or diesel powered vehicle, for providing access to blower  1   12 . In other embodiments, blower  112  may be mounted at different locations on the vehicle, for example on the underside of vehicle  110  or in an air duct that opens through the body of the vehicle. In other embodiments, blower  112  may be mounted on the exterior of the vehicles body, for example on a body panel behind the passenger compartment. 
         [0022]    Blower  112  may be an axial fan-type blower or a centrifugal blower depending on the particular design. Axial fans move air in a direction parallel to the shaft of the fan with fixed or variable pitched blades. Axial fans are used in many applications from cooling fans for personal computers to multi-stage axial fans used to provide compressed air in modem jet engines. 
         [0023]    In one embodiment, blower  112  is driven directly, or indirectly (e.g., though a belt or gearbox), with an electric blower motor  120  mounted on or adjacent the blower in compartment  114 . In one embodiment, motor  120  is a variable speed direct current motor. In other embodiments, motor  120  may be an AC motor with a variable frequency drive for speed control. Electrical power for blower motor  120  may be supplied from battery pack  102 . 
         [0024]    As previously noted, blower  112  may be an axial fan-type blower or a centrifugal blower. Sound parameters such as the volume (dB) and frequency (Hz) of sound generated by an axial fan may be a function of a number of variables including the speed of the fan, the number of blades and the blade design. The configuration and impedance of the fan inlet and outlet as well as the distance between the blade tips and the fan housing or other structures also affects the characteristics of the sound generated by axial fans. Thus, in the cases where blower  112  is an axial fan volume and frequency of sound generated by the blower can be controlled by varying these parameters. 
         [0025]    Alternatively, blower  112  may be a centrifugal blower. Centrifugal blowers typically receive air along a path parallel to a rotating drive shaft and move air in a direction perpendicular to the rotating drive shaft. Centrifugal blowers are used in a wide variety of applications. “Squirrel cage” centrifugal blowers are used to move air in air conditioning and heating units. Centrifugal blowers are also used in vacuum cleaners as well as in turbochargers and superchargers to increase the flow of air to internal combustion engines. 
         [0026]    As in the case of axial flow fans, the frequency (Hz) and volume (dB) and of sound generated by an centrifugal blower is a function of a number of variables including the impeller design and speed and the distance between impeller and the cut off at the blower outlet. The design of the impeller housing as well as the configuration and impedance of the blower inlet and outlet also impact the amount and frequency of sound generated by a centrifugal blower. Consequently, when a centrifugal blower is selected for use as blower  112 , the frequency and volume of sound generated with the blower may be controlled by varying these parameters. 
         [0027]    Referring still to  FIG. 1 , in one embodiment, blower  112  may be actuated with a manually operated switch  122 . When a driver of vehicle  100  wishes to energize blower  112  he or she moves switch  122  to the on position at which time motor  120  is energized. In other embodiments, switch  122  is automatically actuated when vehicle  100  begins to move or when vehicle motor  104  is energized. 
         [0028]    Turning to  FIG. 2 , in one embodiment, when switch  122  is moved to the on position, motor  120  is energized and controlled to operate blower  122  at a base speed “B1” such that the blower produces a base volume of sound “V1.” “V1” may be selected to generate a sound level that is audible over a predetermined distance, for example fifty feet. In this manner, pedestrians and pets would be alerted even if vehicle  100  was stopped at a stop sign or red light. In other embodiments, motor  120  is not energized until the vehicle begins to move. 
         [0029]    As illustrated, the speed of motor  120  and/or blower  112  may be controlled to increase proportionally with the speed of vehicle motor  104  by means of a motion sensor that measures wheel or axle speed. Alternatively, the speed of motor  120  and/or blower  112  may be controlled by means of a sensor that detects the revolutions per minute of vehicle motor or the power supplied to vehicle motor. Thus, as illustrated, the volume (dB) and frequency (Hz) of sound generated by blower  112  increases as the speed of the vehicle increases or the rpm of drive motor  104  increases. In one embodiment, the volume of sound increases linearly with speed as illustrated by line  1 . In other embodiments, the volume of sound increases non-linearly as illustrated by lines  2  and  3 . In still other embodiments, the driver may select between different sound vs. speed profiles (e.g., lines  1 ,  2  or  3 ) by means of a selector switch (not shown) connected to the blower motor  120  or microprocessor  142  ( FIG. 1 ). 
         [0030]    Referring to  FIG. 3 , the speed of motor  120  and/or blower  112  may be controlled to increase or decrease the volume of sound generated proportionally to the vehicle&#39;s acceleration. In one variation, the volume of sound may be a linear function of the vehicle&#39;s acceleration and or deceleration as indicated by line  4 , or alternatively may be a non-linear function of the vehicle&#39;s acceleration or deceleration as illustrated by lines  5  and  6 . Further, the volume and pitch may be varied depending upon whether the vehicle is accelerating or decelerating to simulate the different sounds generated by a conventionally fueled vehicle as it accelerates versus when it decelerates. In still other embodiments, the driver may select between different sound vs. acceleration profiles (e.g., lines  4 ,  5  or  6 ) by means of a selector switch (not shown) connected to the blower motor  120  or microprocessor  142 . 
         [0031]    Referring to  FIG. 4 , the tone or pitch of the sound generated by motor  120  and/or blower  112  vary linearly with the speed of vehicle  100 , the speed of drive motor  104  or the position of the manual speed controller or throttle used by the driver. This effect may be linear as illustrated by line  7 , or non-linear as illustrated by lines  8  and  9 . In still other embodiments, the driver may select between different pitch vs. speed profiles (e.g., lines  7 ,  8  or  9 ) by means of a selector switch (not shown) connected to the blower motor  120  or microprocessor  142 . 
         [0032]    Turning to  FIG. 5 , sound parameters such as the tone, pitch or volume of the sound created by motor  120  and/or blower  112  may be varied in a “stepped” fashion vs. speed/acceleration to simulate the sound of a conventionally fueled vehicle as it is shifted, either manually or by means of an automatic transmission. This effect may be accomplished by changing the speed of motor  120  and/or blower  112  or alternatively by opening or closing a damper at the inlet or outlet of the blower or in a duct connected to the blower. The volume or frequency or the sound generated by motor  120  and/or blower  112  may also be controlled in the case where blower  112  is an axial fan by changing the pitch of the blades or varying the distance between the blades and the blower&#39;s housing or a structure adjacent the blades such as a baffle or plate. In the case of a centrifugal blower, the pitch of the blades and the distance between the impeller and cut-off at the air outlet may be changed to vary the volume or frequency of the sound. In some embodiments, the driver may select between shifting sound profiles (e.g., lines  10  or  11 ) by means of a selector switch (not shown) connected to the blower motor  120  or microprocessor  142 . 
         [0033]    Turning to  FIG. 6 , in yet another variation, the volume and/or frequency of sound generated by motor  120  and/or blower  112  may be pulsed or interrupted to create different audible effects. This effect may be created by, for example, rapidly opening or closing a damper at the inlet or outlet of blower  112  or in ducts connected to the inlet or outlet of the blower. Other means of achieving the pulsed or interrupted sound are possible. 
         [0034]    Referring again to  FIG. 1 , in one variation, one or more inlet ducts  124  may be employed to direct air to the inlet of blower  112 . Inlet ducts  124  may open at the front end  116  of vehicle  100  or may be connected to one or more scoops (not shown) in hood  118  of vehicle  100 . In one embodiment, ducts  124  may be designed and configured to resonate at a desired frequency to enhance the audible effect of blower  112 . 
         [0035]    One or more exhaust ducts  126  may conduct air from blower  112  to drive motor  120  and/or to compartment  110  to cool motor controller  106  and battery pack  104 . Compartment  110  may be provided with an exhaust outlet  136  to facilitate the flow of air through the compartment. Outlet  136  may be provided with a damper  138  that is positioned with a manual or electric actuator  140  to position the damper. Inlet ducts  124  and exhaust ducts  126  may be configured with baffles, restrictions, expansion chambers or other features to resonate at a desired frequency or otherwise affect the sound generated by blower  110 . 
         [0036]    In one embodiment, a valve or damper  128  may direct air from exhaust duct  126  though an outlet  130  in exhaust duct  126 . Damper  128  and/or outlet  130  may be opened and closed with an actuator  132 . Actuator  132  may be an electrically powered linear actuator or rotary actuator such as a stepper motor. In one variation, pressurized air from outlet  130  may be directed into the vehicle&#39;s passenger compartment for ventilation. In this variation, pressurized air from outlet  130  may be passed across a heating or cooling element to heat or cool the vehicle&#39;s passenger compartment. 
         [0037]    Damper  128  may be used to control the amount of cooling air supplied to drive motor  104  as well as motor controller  106  and battery pack  102 . Damper  128  may also be used to vary the volume and/or frequency of sound generated by blower  112 . In one variation, the signal from one or more temperature sensors positioned on or adjacent to drive motor and/or in compartment  110  may be utilized to control the position of damper  128 . Alternatively, damper  128  may be located in inlet duct  124  and or at the inlet of blower  112  to regulate the amount of air flowing into the blower. In one embodiment, the speed of blower motor  120 , and the position of actuators  132  and  140  are controlled with an onboard microprocessor  142  that is programmed to respond to changes in the speed of the drive motor or vehicle&#39;s speed as well as the temperature in compartment  110  and/or the temperature of drive motor  104 . 
         [0038]    Referring now to  FIG. 7 , in an alternate embodiment, an electrically powered vehicle  200  includes a battery pack  202 , an electric motor  204  and a motor controller package  206 . As illustrated, electric drive motor  204  is mounted at the rear  208  of the vehicle with battery pack  202  and motor controller  206  mounted in a compartment  210  above the electric motor. In other variations, battery pack  202 , motor  204  and controller package  206  may be mounted at alternate locations in the vehicle, for example at or near the front of the vehicle or in a mid-body motor configuration or at different locations in the vehicle. 
         [0039]    As illustrated, a pair of air ducts  212 ,  214  having inlet openings  216  at or adjacent front wheel wells  218  of vehicle  200 . Blowers  220  located in each of ducts  212 ,  214  are driven by fixed or variable speed motors  222  mounted in or on ducts  212 ,  214 . Blowers  220  may be either axial fans or centrifugal blowers and are selected to generate a turbine-like or engine-like sound in operation. Ducts  212 ,  214  may be designed and configured with restrictions, baffles, expansion chambers and other features to dampen unwanted frequency sounds and/or enhance desired frequency sounds. 
         [0040]    In one embodiment, intake dampers  224  are positioned in ducts  212 ,  214  between inlet openings  216  and blowers  220 . Dampers  224  may be positioned with linear or rotary actuators  226  to regulate the flow of air to the blowers. The speed of blowers  220  and/or position of dampers  224  may be controlled based on the speed of vehicle  200 , the rpm of drive motor  204  and/or the temperature of the drive motor, battery pack  202  or motor controller  206 . In one embodiment, the speed of blowers  220  is controlled based on the speed of vehicle  200  or rpm of drive motor  204  while the position of dampers  224  is based on the temperature of the drive motor, battery pack  202  or motor controller  206 . The speed of blowers  220  may be controlled to vary the dB level of the sound generated by the blowers as generally illustrated in  FIG. 2 . In this manner, blowers  220  may be operated at the speed required to generate the desired sound levels while supplying the needed amount of cooling air to the electrical components of vehicle  200 . 
         [0041]    In one embodiment, one of ducts  212 ,  214  discharges into compartment  210  to provide cooling to battery pack  202  or motor controller  206  while the other duct is configured to discharge cooling air directly on or adjacent to drive motor  204 . In this variation, the position of each of dampers  224  may be independently controlled based on the temperature in compartment  110  or the temperature of drive motor  204  as measured by temperature sensors  228  mounted in the compartment and on or adjacent the drive motor. In one embodiment, sensors  228  are connected to a controller  230  that is programmed to control blowers  220  and dampers  224 . Controller  230  may be connected to a manually activated switch  232 , allowing the driver the option of operating vehicle  200  with blowers on or off, in a silent mode, with the blowers de-energized. In one variation, controller  230  is programmed to operate blowers  220  for a predetermined period of time after drive motor  204  is de-energized to prevent over heating. In another variation, controller  230  is programmed to operate blowers  220  based on the temperature of the drive motor  204  and/or battery pack  202  and motor controller  206 , regardless of whether or not the drive motor is energized. 
         [0042]    Turning to  FIG. 8 , in another variation, an electrically powered vehicle  300  includes a battery or battery pack  302 , an electric drive motor  304  and a motor controller package  306 . In this variation, a blower  312  is mounted externally on the body of vehicle  300 . Blower  312  is driven by a variable speed electric drive motor  320  to direct air onto battery pack  302 , motor controller  306  and/or electric drive motor  304 . The speed of motor  320  and/or blower  312  may be controlled as described above to vary the frequency and volume of sound generated by the blower. A damper  328  may be mounted in the outlet  330  of blower  312  to regulate the flow of air directed to onto battery pack  302 , motor controller  306  and/or electric drive motor  304 . Damper  328  may be positioned with a manual or electric actuator (not shown). 
         [0043]    It will be appreciated by those skilled in the art having the benefit of this disclosure that this electrically propelled vehicle having electric sound-producing blower/cooler provides a rotary air mover and sound generator for an electrically propelled vehicle. It should be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to be limiting to the particular forms and examples disclosed. On the contrary, included are any further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments apparent to those of ordinary skill in the art, without departing from the spirit and scope hereof, as defined by the following claims. Thus, it is intended that the following claims be interpreted to embrace all such further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments.