Abstract:
A method for providing a shift position indication in an automatic transmission comprising the steps of providing a display device, sensing a position of an input device, the input device being responsive to manipulation by a driver and having a plurality of input positions, sensing an active gear ratio, and modifying the display device to display the position of the input device and the active gear ratio. An apparatus for displaying information on both the position of the shift lever and the activated gear ratio is also provided.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to vehicle gear shift (PRNDL) displays and more particularly to a vehicle gear shift display which indicates both the position of a gear shift lever and a currently active gear ratio. 
     2. Discussion 
     Generally, conventional shift lever position displays (PRNDL displays) for automatic transmissions provide the vehicle operator with an indication of the position of the shift lever. Where the transmission may also be operated in a ‘manual’ automatic mode (i.e., the driver determines the timing of the shift but activation of the transmission clutches is performed automatically), several types of PRNDL displays are also operable in a mode wherein the activated gear ratio is displayed. One drawback of these PRNDL displays is that no feedback on both the position of the shift lever and the activated gear ratio is provided to the vehicle operator. Information on both the position of the shift lever and the activated gear ratio is desirable in that it permits the vehicle operator to monitor the configuration and performance of the vehicle when the transmission is controlled in an automatic mode. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide a method for providing a shift position indication in an automatic transmission wherein information on both the position of the shift lever and the activated gear ratio is displayed to the vehicle operator. 
     It is another object of the present invention to provide an apparatus for displaying information on both the position of the shift lever and the activated gear ratio. 
     In one form, the present invention provides a method for providing a shift position indication in an automatic transmission comprising the steps of providing a display device, sensing a position of an input device, the input device being responsive to manipulation by a driver and having a plurality of input positions, sensing an active gear ratio, and modifying the display device to display the position of the input device and the active gear ratio. An apparatus for displaying information on both the position of the shift lever and the activated gear ratio is also provided. 
     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 schematic illustration of a portion of a vehicle constructed in accordance with the teachings of the present invention; 
     FIG. 2 is a schematic illustration of a portion of the vehicle of FIG. 1 illustrating the vehicle dash panel; 
     FIG. 3 illustrates a portion of the display device of FIG. 2 as operated in a first operational mode; 
     FIGS. 4 through 7 illustrate a portion of the display device of FIG. 2 as operated in a second operational mode; and 
     FIGS. 8 through 11 illustrate a portion of the display device of FIG. 2 as operated in a third operational mode. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIGS. 1 and 2, a vehicle is schematically indicated by reference numeral  10 . In the particular embodiment illustrated, vehicle  10  is shown to include an engine  12 , an automatic transmission  14 , an engine controller  16 , a transmission controller  18 , a plurality of first sensors  20 , an input device  22 , at least one second sensor  24  and a display device  26 . Engine  12 , transmission  14 , engine controller  16  and the plurality of first sensors  20  are conventional in their construction and operation and as such, need not be described in detail. Briefly, engine  12  is operable for providing a rotational output which is received by transmission  14 . Transmission  14  includes a plurality of gear ratios which are operable in an active mode for transmitting drive torque to the vehicle wheels  28  and an inactive mode in which they do not transmit drive torque. In the example provided, transmission  14  includes a first gear ratio, a second gear ratio, a third gear ratio and a fourth or overdrive gear ratio. First sensors  20  are coupled to vehicle  10  and are operable for sensing a plurality of vehicle dynamics and outputting a plurality of first sensor signals in response thereto. At least one of the plurality of first sensors  20  is coupled to transmission  14  and is operable for producing a gear ratio signal indicative of the active gear ratio. Engine controller  16  receives the first sensor signals and controls the operation of the engine  12  in response thereto. 
     Transmission controller  18  is coupled to transmission  14  and is operable for selectively activating and de-activating each of the plurality of gear ratios according to a predetermined shift schedule, the plurality of first sensor signals including the gear ratio signal, and the position signal (discussed below). Preferably, transmission controller  18  is selectively operable in a first automatic mode having a first predetermined shift schedule, a second automatic mode having a second predetermined shift schedule and a manual forward mode having a driver determined shift schedule. Transmission controller  18  is adapted in each of the first and second automatic modes to responsively shift transmission  14  in response to the plurality of first sensor signals. Transmission controller  18  is also coupled to engine controller  16  and display device  26  to permit sharing of various vehicle, engine and transmission data. In the example provided, transmission controller  18 , engine controller  16  and display device  26  are coupled via a multiplex data bus. 
     Input device  22  is operable for cooperating with transmission controller  18  to control the operation of transmission  14 . Input device  22  is responsive to manipulation by a driver and is positionable in a plurality of input positions. The second sensor  24  determines the position of the input device  22  and produces a position signal in response thereto. In particular, input device  22  is shown to include a lever  30  which may be operated as described in commonly assigned U.S. application Ser. No. 09/316,314 entitled “Apparatus and Method for Selecting a Manual Mode of Shifting an Automatic Transmission”, U.S. application Ser. No. 09/316,605 entitled “Apparatus and Method for Providing Automatic Shift Modes in an Automatic Transmission”, and U.S. application Ser. No. 09/316,946 entitled “Apparatus and Method for Manually Shifting an Automatic Transmission”, all of which are hereby incorporated by reference as if fully set forth herein. Those skilled in the art will understand that input device  22  could also be a conventional shift lever for an automatic transmission which is coupled to the transmission via a link member for shifting the position of a spool valve to direct hydraulic fluid in a predetermined manner. 
     Display device  26  is illustrated in FIG. 2 to include a display mode selector switch  32  and a gear lever position display (PRNDL display)  34  having a plurality of display positions  36 . Display device  26  is coupled and responsive to transmission controller  18 . PRNDL display  34  is preferably a vacuum fluorescent display which is selectively operable in a plurality of modes. Operation of PRNDL display  34  in a first display mode causes the continuous illumination of the display position  36  that corresponds to the position of the input device  22 . Operation of PRNDL display  34  in a second display mode causes the illumination of the display position or positions that correspond to the active gear ratio and the position of the input device  22 . Operation of the PRNDL display  34  in a third display mode causes the illumination of the display position that corresponds to the active gear ratio. Display mode selector switch  32  is operable for transmitting a mode input signal to display device  26  to switch PRNDL display  34  between the first, second and third display modes. Those skilled in the art will understand that display mode selector switch  32  may be comprised of two or more switches located throughout vehicle  10  to permit one or more of the display modes to be actuated automatically upon the sensing of a predetermined condition. For example, second sensor  24  may be employed to automatically actuate one of the display modes when the input device  22  is moved to a predetermined position. 
     FIG. 3 illustrates the operation of the PRNDL display  34  in the first display mode. In this example, transmission controller  18  operates in the first automatic mode wherein transmission  14  is controlled according to a first shift schedule that conventionally upshifts and downshifts from one gear ratio to another gear ratio without manipulation of the input device  22 . Accordingly, when the transmission controller  18  is operated in the first automatic mode and the driver positions the input device  22  in the “D” position, the PRNDL display  34  will continuously illuminate the display position  36 a corresponding to “D” regardless of which of the actual forward gear ratios is active. 
     FIGS. 4 through 7 illustrate the operation of the PRNDL display  34  in a second display mode. A mode indicator  38   a  indicates to the vehicle operator that the display device  26  is being operated in the second display mode. In this example, the input device  22  is placed in the “D” position and vehicle  10  is proceeding from a stop at a relatively low rate of speed. Accordingly, display positions  36   a  and  36   b  are illuminated as shown in FIG. 4 as they corresponding to the placement of the input device  22  in the “D” position and the operation of transmission  14  in the first gear ratio, respectively. 
     As the speed of vehicle  10  increases, transmission controller  18  causes transmission to upshift to the second gear ratio and the PRNDL display  34  updates as illustrated in FIG.  5 . As shown, display positions  36   a  and  36   c  are illuminated as they corresponding to the placement of the input device  22  in the “D” position and the operation of transmission  14  in the second gear ratio, respectively. 
     When the speed of vehicle  10  increases sufficiently, transmission controller  18  causes transmission to upshift to the third gear ratio and the PRNDL display  34  updates as illustrated in FIG.  6 . As shown, display positions  36   a  and  36   d  are illuminated as they corresponding to the placement of the input device  22  in the “D” position and the operation of transmission  14  in the third gear ratio, respectively. 
     As the speed of vehicle  10  further increases, transmission controller  18  causes transmission to upshift to the fourth or overdrive gear ratio and the PRNDL display  34  updates as illustrated in FIG.  7 . As shown, display positions  36   a  and  36   e  are illuminated as they corresponding to the placement of the input device  22  in the “D” position and the operation of transmission  14  in the fourth or overdrive gear ratio, respectively. 
     The operation of the PRNDL display  34  may be associated with a predetermined shift schedule, such as an enhanced (aggressive) performance schedule or an overdrive schedule in which an overdrive gear ratio cannot be activated when the input device is placed at any other input position. In the example provided, operation of the PRNDL display  34  in the first display mode causes the transmission controller  18  to operate in the first automatic mode wherein the transmission controller  18  causes the transmission  14  to perform an upshift between a first gear ratio and a second gear ratio at a first engine rotational speed and operation of the PRNDL display in the second display mode causes the transmission controller  18  to operate in the second automatic mode wherein the transmission controller  18  causes the transmission  14  to perform an upshift between the first and second gear ratios at a second and possibly higher engine rotational speed. Accordingly, operation of the PRNDL display  34  in the first display mode may be associated with the fuel efficiency of vehicle  10 , and operation of the PRNDL display  34  in the second display mode may be associated with higher performance. 
     FIGS. 8 through 11 illustrate the operation of the PRNDL display  34  in a third display mode. A mode indicator  38   b  indicates to the vehicle operator that the display device  26  is being operated in the second display mode. In this example, the active gear ratio is displayed on the PRNDL display. Accordingly, to begin forward movement, the input device  22  is first positioned in the lowest gear ratio as shown in FIG.  8 . As shown, only the display position  36   b  is illuminated. As the speed of vehicle  10  increases, the driver manipulates the input device  22  and causes transmission to upshift to the second gear ratio. The PRNDL display  34  updates, illuminating display position  36   c  as illustrated in FIG.  9 . 
     When the speed of vehicle  10  increases sufficiently, the driver manipulates the input device  22  and causes transmission to upshift to the third gear ratio. The PRNDL display  34  updates, illuminating display position  36   d  as illustrated in FIG.  10 . 
     As the speed of vehicle  10  further increases, the driver manipulates the input device  22  and causes transmission to upshift to the fourth gear ratio. Accordingly, PRNDL display  34  updates as illustrated in FIG.  11 . As shown, display position  36   e  is illuminated as is corresponds to the operation of transmission  14  in the fourth gear ratio, respectively. 
     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.