Abstract:
An improved sunroof assembly is provided. The sunroof assembly includes a sunroof portion and an air dam portion. The sunroof portion includes a sunroof panel which is positionable between an open and a closed position. The air dam portion includes an air dam structure, a drive assembly and a wind noise determining portion. The air dam structure is pivotally coupled to the sunroof portion and is positionable between a retracted position and an extended position. The drive assembly is coupled to the sunroof portion and the air dam structure and operable for positioning the air dam structure between the retracted position and the extended position. The wind noise determining system determines the amount and characteristics of the noise transmitted into the vehicle passenger compartment through sunroof assembly and generates a signal in response thereto. Drive assembly interprets the signal and selectively repositions air dam structure in predetermined control method to vary the position of air dam structure so as to minimize the wind noise transmitted into a vehicle passenger compartment.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention pertains generally to vehicle sunroof systems and more particularly, to vehicle sunroof systems which attenuate wind noise transmitted into the vehicle passenger compartment while the vehicle is operated and the sunroof is in an open condition. 
     2. Discussion 
     It has become commonplace to employ sunroof assemblies in automotive vehicle roof systems. Such sunroof assemblies offer sunlight access through a fixed vehicle roof opening when a sunroof panel is disposed in either an open or closed position, and an opaque sunshade is openly slid. Furthermore, open air motoring access is provided through a sun roof aperture when the sunroof panel is fully opened, thereby increasing ventilation within the passenger compartment. 
     Most conventional sunroof assemblies have a sunroof tub, an electric motor, a cable driven drive mechanism and a sunroof panel. A driver accessible switch is also typically provided for selectively energizing and de-energizing the electric motor in a manual manner. These conventional sunroof assemblies move the sunroof panel between a fully closed position generally flush with the exterior of the vehicle roof and a fully open position either stowed below or above the stationary vehicle roof. 
     Many conventional sunroof assemblies have problems with noise that is transmitted into the vehicle passenger compartment which results from the flow of air proximate the sunroof aperture. One component of the wind noise typically results from wind buffeting and is generally characterized by low frequencies. Another component of the wind noise typically results from wind rushing over the vehicle trim and other vehicle components (e.g., antenna) and is generally characterized by high frequencies. 
     In an effort to attenuate the low frequency portion of the wind noise, air dams have frequently been incorporated into sunroof assemblies. These air dams generally pivot from a retracted position when the sunroof panel is into and an extended position when the sunroof panel is opened. Various air dam constructions have been suggested or employed to affect the low-frequency portion of wind noise and/or to improve air flow into the passenger compartment. While air dams have been employed with some success in attenuating low-frequency noise in certain situations, several drawbacks have been noted. 
     One drawback relates to the positioning of the air dam at the fully extended position regardless of the speed of the vehicle or the amount that sunroof panel is open. It is well known in the art that both of these factors greatly influence the magnitude of the low-frequency portion of the wind noise, yet these systems do not adjust the position of the air dam between the retracted and extended positions to optimize performance of the air dam. Furthermore, these air dams are typically constructed with little regard to substantially attenuate the high-frequency portion of the wind noise. 
     Other efforts in this area have focused on variable positioning of the sunroof panel as the vehicle speed changes. While this strategy has greatly attenuated the magnitude of the low-frequency portion of the wind noise, this strategy does not substantially attenuate the magnitude of the high-frequency portion of wind noise. 
     SUMMARY OF THE INVENTION 
     It is therefore one object of the present invention to provide an improved sunroof apparatus which attenuates the wind noise transmitted into the vehicle passenger compartment from a sunroof aperture. 
     It is another object of the present invention to provide an improved sunroof apparatus having an air dam which may be selectively positioned between a retracted position and an extended position to attenuate portions of the wind noise which is transmitted into a vehicle passenger compartment. 
     An improved sunroof assembly is provided. The sunroof assembly includes a sunroof portion and an air dam portion. The sunroof portion includes a sunroof panel which is positionable between an open and a closed position. The air dam portion includes an air dam structure, a drive assembly and a wind noise determining portion. The air dam structure is pivotally coupled to the sunroof portion and is positionable between a retracted position and an extended position. The positioning assembly coupled to the sunroof portion and the air dam structure and operable for positioning the air dam structure between the retracted position and the extended position. The wind noise determining system determines the amount and characteristics of the noise transmitted into the vehicle passenger compartment through sunroof assembly and generates a signal in response thereto. Positioning apparatus interprets the signal and selectively repositions air dam structure in predetermined control method to vary the position of air dam structure so as to minimize the wind noise transmitted into a vehicle passenger compartment. 
    
    
     Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a portion of a vehicle incorporating a sunroof constructed according to the teachings of the present invention; 
     FIG. 2 is an exploded perspective view of a portion of the vehicle of FIG. 1; 
     FIG. 3 is a cross-sectional view of the vehicle of FIG. 1 taken along the line  3 — 3 ; 
     FIG. 4 is a schematic diagram of the electrical control system for a portion of the sunroof of the present invention; 
     FIG. 5 is a diagram schematically illustrating the a portion of the electrical control system of FIG. 4; 
     FIG. 6 is a perspective view of a portion of the vehicle of FIG. 1; and 
     FIG. 7 is a schematic diagram of a system constructed according to an alternate embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIGS. 1 and 2 of the drawings, a motor vehicle constructed in accordance with the teachings of the preferred embodiment of the present invention is generally identified at reference numeral  10 . As will be discussed in greater detail below, vehicle  10  includes a vehicle body  14  and a closure apparatus, such as sunroof apparatus  18 . Although the particular closure apparatus illustrated is a sunroof apparatus, it will be understood that the teachings of the present invention have applicability to other types of closure members which are coupled to the body of a structure to selectively cover an aperture formed into the body. 
     Body  14  includes a generally horizontal roof member  24  defining a sunroof aperture  28 . Roof member  24  is disposed above the vehicle passenger compartment  32 . Sunroof aperture  28  extends through roof member  24  to permit air and light to enter into passenger compartment  32 . 
     Sunroof apparatus  18  is disposed within sunroof aperture  28  includes a sunroof portion  36  and an air dam portion  38 . Sunroof portion includes a sunroof panel  40 , a sunroof tub  44 , a first actuator  48 , an electronic control unit  52  and a pair of slide mechanisms  56  (only one shown). A driver-accessible toggle or push/push switch  60  is coupled to electronic control unit  52  and is operable for causing first actuator  48  to actuate to open or close sunroof panel  40  as desired. 
     As best shown in FIG. 3, sunroof tub  44  includes a lateral sidewall  62  which extends generally vertically upward from passenger compartment  32 . Lateral sidewall includes a positioning aperture  64  having a major axis  66  which is generally parallel the longitudinal axis of vehicle  10 . Positioning aperture  64  is bounded by a pair of spaced apart sidewalls  66   a ,  66   b.    
     Sunroof panel  40 , sunroof tub  44 , first actuator  48 , slide mechanisms  56   a ,  56   b  and switch  60  are otherwise conventional in construction and do not require further discussion. Sunroof tub  44  is disposed within sunroof aperture  28  and coupled to roof member  24  in a conventional manner. 
     As best shown in FIG. 3, air dam portion  38  is shown to include an air dam structure  80 , a first pin  84 , a positioning apparatus  88  and a wind noise determining apparatus  92 . First pin  84  pivotally couples air dam structure  80  to tub  44  and permits air dam structure  80  to pivot between a retracted position (not specifically shown) and a fully extended position as indicated by reference letter A. Air dam structure  80  includes a curved exterior surface  96  which is operable for directing air flow  100  proximate sunroof aperture  28 . The manner in which exterior surface  96  directs air flow  100  is dependant upon the positioning of air dam structure  80  between the retracted and extended positions. Air dam structure  80  is conventional in this regard and this aspect need not be discussed in further detail. Air dam structure  80  also includes a pin aperture  104  located in one of its lateral sides  108 . Pin aperture  104  will be discussed in further detail, below. 
     Positioning apparatus  88  is shown to include a first positioning member  120 , a drive assembly  124 , and first and second pivot pins  128   a ,  128   b  and a roller pin  132 . First pivot pin  128   a  pivotally couples first positioning member  120  to air dam structure  80 . Roller pin  132  extends through a pin aperture (not shown) in first positioning member  120  and through positioning aperture  62 . Roller pin  132  is coupled to first positioning member  120  and slidingly engages at least one of the sidewalls  66   a ,  66   b . Drive assembly  124  is pivotally coupled to first positioning member  120  through second pivot pin  128   b . Operation of drive assembly  124  causes a second positioning member  140  to rotate about a pivot point  141  to cause first positioning member  120  to rotate air dam structure  80  between the retracted and extended positions as desired. 
     In the particular embodiment illustrated, drive assembly  124  includes a second positioning member  140 , a drive motor  144 , preferably a stepper motor or a servo motor, and a controller  148 . A first end of second positioning member  140  is pivotally coupled to first positioning member through second pivot pin  128   b . A second, distal end of second positioning member  140  is coupled for rotation with the output shaft of motor  144 . Controller  148  is electrically coupled to drive motor  144  through wire harness  152  and controls the operation of drive motor  144 . Drive motor  144  can be controlled to rotate in a first direction to transmit an upwardly directed force from second positioning member  140  to first positioning member  120  and cause air dam structure  80  to be positioned toward or into the extended position. Similarly, drive motor  144  may be controlled to rotate in a second direction to transmit a downwardly directed force from second positioning member  140  to first positioning member  120  and cause air dam structure  80  to be positioned toward or into the retracted position. 
     In FIG. 4, wind noise determining apparatus  92  is operable for determining the magnitude and character of the wind noise transmitted into passenger compartment  32 . In the particular embodiment illustrated in FIGS. 5, wind noise determining apparatus  92  includes a wind noise sensor  170  and a signal processor  174 . With additional reference to FIGS. 1 and 4, wind noise sensor  170  is shown to include a microphone  178 . Microphone  178  is mounted to vehicle body  14  proximate sunroof aperture  28  and is operable for producing a microphone output signal indicative of the amplitude and character of the noise entering passenger compartment  32  which results from air flow  100 . Microphone  178  is conventional and as such, will not be discussed in further detail. 
     Microphone output signal is received by signal processor  174  where it is processed in a predetermined manner. In the particular embodiment illustrated, microphone output signal is processed through an amplifier  182  after which it is split into two portions. A first portion of the microphone output signal is directed into a first processor  186  and a second portion of the microphone output signal is directed into a second processor  190 . First processor  186  is operable for filtering the first portion of the microphone output signal to remove all of the signal except for the portion which is associated with a predetermined first range of wind noise frequencies. Similarly, second processor  190  is operable for filtering the second portion of the microphone output signal to remove all of the signal except for the portion which is associated with a predetermined second range of wind noise frequencies. 
     In a preferred embodiment of the present invention, first processor  186  is operable for filtering out all of the microphone output signal except for the portion of the signal that relates low-frequency noise having a maximum frequency of about 200 Hz and second processor  190  is operable for filtering out all of the microphone output signal except for the potion of the signal that relates to high-frequency noise having a frequency below about 6 kHz. Optimal frequency ranges may need to be tuned to a particular model of vehicle to compensate for variances in the generation of noise which are design related, including the placement of the vehicle radio antenna, the rake or angle of the vehicle windshield, the volume of the passenger compartment, the size of the sunroof aperture  28 , etc. 
     Also in a preferred embodiment, first and second processors  186  and  190  are operable for producing first and second processor output signals, respectively, which are indicative of the amount of low-frequency and high-frequency noise, respectively. Preferably, first and second processor output signals are digital signals indicative of whether the magnitude of the low-frequency and high-frequency noise has exceeded predetermined low-frequency and high-frequency noise levels, respectively. 
     The first and second processor output signals are received by controller  148 . Then, as necessary, controller  148  controls drive motor  144  according to a predetermined control strategy to adjust air dam structure  80  between the retracted and extended positions to balance the first and second frequency ranges of the wind noise in a predetermined manner. In the particular embodiment illustrated, controller  148  includes an operational amplifier  194  which compares the digital first and second processor output signals. 
     When sunroof panel  40  is to be moved to the closed position, drive motor  144  may be controlled to draw air dam structure  80  into the retracted position in a predetermined manner. Alternatively, as best shown in FIG. 3, first positioning member  120  may be configured in a manner such that as first actuator  48  drives sunroof panel  40  toward the closed position, the leading edge  200  of sunroof panel  40  contacts and transmits a downwardly directed force to first positioning member  120 , causing first positioning member  120  to rotate about first pivot pin  128   a  into the retracted position. 
     While the sunroof apparatus of the present invention has been described thus far as having an air dam positioning apparatus which includes a drive motor and a wind noise determining apparatus which includes a microphone and filtering the wind noise signal at two fixed ranges, those skilled in the art will appreciate that the invention, in its broader aspects, may be constructed somewhat differently. For example, air dam positioning apparatus may include various other devices to selectively position air dam structure  80  between the retracted and extended positions. Such devices are conventionally known and include, for example, linear motors, variable displacement solenoids, fluid-powered cylinders or a drive rack. 
     Another example of a somewhat different construction of the sunroof apparatus of the present invention is illustrated in FIG. 6. A control panel  602  adjacent to sunroof apparatus  18 ′ includes first and second slider control buttons  606   a ,  606   b  in addition to switch  60 . First and second slider control buttons  606   a ,  606   b  are operable for adjusting the threshold levels of the high-frequency noise and low-frequency noise, respectively. These controls permit the vehicle occupant to adjust the control of the air dam structure to favor increased attenuation of one type of noise. For example, if the vehicle occupants find the high-frequency noise particularly irritating or distracting, they may adjust the control of air dam structure to focus on the attenuation of the high-frequency noise so as to slightly reduce it or eliminate it altogether. 
     Alternatively, first and second slider control buttons  606   a ,  606   b  may be operable for adjusting the value of the maximum and minimum attenuation frequencies to accommodate the hearing of particular vehicle occupants. This permits the minimum attenuation frequency associated with the high-frequency wind noise to be adjusted from 6 kHz to 5 kHz, for example. 
     Another example is illustrated in FIG.  7 . Wind noise determining apparatus “is illustrated as a speedometer  702  which produces a speed signal indicative of the speed of vehicle  10 ”. Speed signal is received by controller  148  ″ which utilizes a predetermined methodology to control the structure  80 . The predetermined methodology is based upon empirical testing to associate the speed of vehicle  10 ″ to the optimal position of the air dam structure. 
     While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the description of the appended claims.