Background of the Invention

This invention relates to electrical control apparatuses and more particularly to electric control apparatuses for controlling various functions of a motor vehicle.

Modern day motor vehicles typically include an automatic transmission in which the shifting is done in response to sensed speed and throttle opening parameters. A typical motor vehicle further includes backup lights which are automatically energized in response to placement of the transmission in a reverse mode and a starter motor which may be enabled only with the transmission in a neutral or park mode. Various control devices have been provided to selectively shift the transmission at the operator's command, to provide a neutral or park signal to enable starting of the engine of the motor vehicle, and to provide a reverse signal to provide energization of the backup lamp circuitry. Typically, the devices controlling the shifting of the transmission, the enabling of the starter motor circuit, and the energization of the backup lamp circuit have comprised separate devices and, as such, have been, in composite, rather expensive and prone to maintenance requirements. It is further important in such electric shift systems that some means be provided to continuously display the present shift position of the transmission to the

driver and it is further important to ensure that the means for displaying the present transmission shift position are working properly.

Summary of the Invention This invention is directed to the provision of an improved electric control apparatus for a motor vehicle.

More specifically, this invention is directed to the provision of a control apparatus for selectively shifting the transmission of the vehicle and for simultaneously providing a starter enable signal for the vehicle as well as a backup lamp signal for the vehicle.

This invention is also directed to the provision of an electric transmission control for a motor vehicle including means that continuously display the present shift position of the transmission and means to readily ensure that the transmission shift position display means are working properly.

The electric control apparatus of the invention is intended for use with a motor vehicle of the type having a starter motor circuit and a transmission having a plurality of states including a neutral state. The invention control apparatus comprises a transmission state sensing means for generating a plurality of present transmission state signals respectively indicating and corresponding to the various states of the transmission and means operative in response to receipt of a neutral transmission state signal to enable the starter motor circuit. This arrangement allows the utilization of the

transmission state sensing means typically forming a part of the electric shift apparatus to also be utilized to provide the neutral start signal to enable the starter motor circuit of the vehicle. According to a further feature of the invention, the motor vehicle has a backup light circuit, the transmission has a reverse state, and the control apparatus further includes means operative in response to receipt of a reverse transmission state signal to energize the backup light circuit. This arrangement allows the available transmission state signal to be further utilized to energize the backup lamp in response to placement of the transmission in a reverse state.

According to a further feature of the invention, the operative means includes a logic control unit receiving the present transmission state signals from the sensing means and operative to enable the starter-motor circuit in response to receipt of a neutral transmission state signal from the sensing means and to energize the backup lamp circuit in response to receipt of a reverse transmission state signal from the sensing means. This arrangement allows a common logic unit to be utilized in the control of the transmission as well as to provide a neutral start signal and a backup lamp signal. According to a further feature of the invention, the transmission includes a mode select shaft operative in response to rotation thereof to selectively position the transmission in its various states and the transmission state sensing means includes encoder means tracking the

angular position of the mode select shaft and operative to generate a plurality of transmission state signals for delivery to the logic control unit corresponding to respective angular positions of the mode select shaft related to respective states of the transmission. This arrangement provides a convenient means of determining the present state of the transmission for use in shifting the transmission as well as for use in providing a neutral start signal and a reverse backup lamp signal. According to a further feature of the invention, the control system includes operator input means in the form of a gear selector assembly enabling the vehicle operator to select a desired transmission state; enunciator means associated with each gear selector assembly select position and operative when individually activated to distinguish the associated select position from the other select positions; means operative to activate the enunciator means associated with the gear selector assembly select position corresponding to the instantaneous shift position of the transmission; and means operative in response to movement of the ignition switch of the vehicle to an activated position to activate all the enunciator means and to thereafter deactivate all the enunciator means with the exception of the enunciator means associated with the gear selector assembly select position corresponding to the instantaneous shift position of the transmission. This arrangement provides the operator with a clear indication at all times of the instantaneous state or position of the transmission and further provide a system check each time

the ignition switch is initially moved to its activated position.

In the disclosed embodiment of the invention, the control apparatus includes means generating a desired transmission state signal corresponding to the operator input to the gear selector assembly and a logic control unit interconnected between the operator input means and the transmission state sensing means and operative to shift the transmission to the desired transmission state as indicated by the operator input means if the desired transmission state differs from the present transmission state as determined by the sensing means and further operative in response to receipt of a neutral transmission state signal to enable the starter motor circuit and still further operative in response to receipt of a reverse transmission state signal to energize the backup lamp circuit.

Brief Description of the Drawings

FIGURE 1 is a fragmentary perspective view of a front wheel drive motor vehicle embodying the invention electric control apparatus;

FIGURE 2 is a fragmentary plan view of the front wheel drive assembly of the vehicle of FIGURE 1;

FIGURE 3 is a view taken on line 3-3 of FIGURE 2;

FIGURE 4 is a fragmentary exploded perspective view of the structure within the circle 4 of FIGURE 3;

FIGURE 5 is a view taken on line 5-5 of FIGURE 3;

FIGURE 6 is a fragmentary perspective view of a control module employed in the invention electric control apparatus;

FIGURE 7 is a circuit diagram for the invention electric control apparatus;

FIGURE 8 shows further circuit detail of the circuit diagram shown in FIGURE 7;

FIGURE 9 is a fragmentary perspective view of an alternate embodiment of the invention electric control apparatus;

FIGURE 10 is a fragmentary plan view of a motor vehicle utilizing the control apparatus of FIGURE 9;

FIGURE 11 is a block diagram of the control apparatus of FIGURE 9; and FIGURE 12 is a fragmentary schematic view of an alternate display arrangement for the control apparatus of FIGURE 9.

Detailed Description of the Preferred Embodiment

The invention electric control apparatus is seen schematically in Figure 1 in association with a motor vehicle of the front wheel drive type and including an instrument panel assembly 10 positioned within the passenger compartment of the motor vehicle; a steering wheel 12 associated with the instrument panel; an accelerator pedal assembly 14; and a front wheel drive assembly 16.

Front wheel drive assembly 16 includes an internal combustion engine 18 mounted transversely in the

engine compartment of the vehicle, a torque converter 20 driven by engine 18, a gear drive assembly 22, an automatic transmission 24, and drive shafts 26 drivingly connected to the opposite ends of transmission 24 by U joints 28. Transmission 24 includes a mode select shaft 30 having a free upper end positioned above the housing 32 of the transmission 24 and operable in known manner in response to rotation of the shaft to operate internal devices within the transmission to position the transmission in a plurality of transmission modes such as park, neutral, drive, etc.

The invention electric control apparatus, broadly considered, comprises a power module 34 and a control module 36. Power module 34 is adapted to be bolted to transmission housing 32 in proximity to mode select shaft 30 and control module 36 is adapted to be positioned in the instrument panel assembly 10 of the vehicle for convenient operator access. Power module 34 is in the form of a motor assembly and includes a DC electric motor 38 and a speed reduction unit 40.

Motor 38 is a direct current motor having, for example, an output torque rating of 200 inch pounds and includes a housing 42 and an output shaft 44.

Speed reduction unit 40 includes a housing 46 fixedly secured to motor housing 42 and defining an internal cavity 46a, a worm gear 48 formed as a coaxial extension of motor output shaft 44 and extending into

cavity 46a, a worm wheel 50 positioned in cavity 46a and driven by worm gear 48, and an output ^" shaft 52 driven by worm wheel 50, journalled in housing walls 46b and 46, and including a free lower end 52a positioned outside of and below housing wall 46c. Shaft lower end 52a includes a D shaped opening 52b for driving, coupling receipt of the D shaped upper end portion 30a of mode select shaft 30.

Motor assembly 34 is mounted on the upper face of transmission housing 32 by a plurality of bolts 54 passing downwardly through bores 46d in lug portions 46e of reduction unit housing 46 and downwardly through spacers 56 for threaded receipt in tapped bores 32a in transmission housing 32. In assembled relation, reduction unit output shaft 42 is coaxially aligned with mode select shaft 30, and D opening 52b in reduction shaft lower end 52a telescopically receives D shaped upper end 30a of mode select shaft 30 so that actuation of motor 38 acts through worm shaft 48, worm wheel 50, and reduction unit output shaft 52 to drive mode select shaft 30. Power module 34 further includes an encoder assembly 72 operative to sense the instantaneous shift state or position of the transmission and generate an encoded signal representative of the sensed shift position.

Encoder assembly 72 includes an encoder wheel 74 and a pickup device 76. Encoder wheel 74 may be formed for example of a suitable plastic material and is secured to a side face of worm wheel 50 within reduction unit housing chamber 46a. Encoder wheel 74 includes a central aperture 74a passing speed reduction unit output shaft 42 and

further includes code indicia 80 provided on the exposed outer face of the wheel and arranged ^" along four arcuate tracks 80a, 80b, 80c and 80d centered on the center line of the encoder wheel. Pickup device 76 includes a plastic body member

82 mounting a plurality of flexible resilient contact fingers 84 for respective coaction with indicia tracks 80a, 80b, 80c and 80d. In addition to the four fingers 84 for respective engagement with the four indicia racks, a fifth finger is provided to provide a ground for the system.

A lead 86 from motor 42 and a lead 88 from pickup device 76 are combined into a pin-type plug 90.

Control module 36 is intended for ready installation in an opening 10a in instrument panel 10 by insertion of the module from the rear of the panel and fastening of the module within opening 10a by the use of several fasteners such as seen at 96. module 36 includes a housing structure 98 of general box-like configuration enclosing an operator access or push button submodule 36a and a logic submodule 36b.

Push button submodule 30a includes a plurality of push buttons 100 positioned in vertically spaced relation in the front face 98a of the module housing and corresponding to the available transmission shift modes. Specifically, bottoms 100 include buttons corresponding to park, reverse, neutral, over-drive, drive, second and first shift positions for the transmission. Buttons 100 coact in known manner with a printed circuit board 102 to generate

suitable electrical signals in response to respective depression of the buttons 100.

Logic submodule 36b includes an electronic printed circuit board 104 suitably electrically connected to printed circuit 102 and suitably mounting a first plurality of connector terminals 106 and a second plurality of connector terminals 108. Connector terminals 106 coact with a pin-type plug 110 at the end of a cable 112. Cable 112 includes a plug 114 at its remote end for plugging receipt of plug 90 so that plug 110 embodies the information from leads 86 and 88. Connector terminals 108 coact with a pin-type plug 118. Plug 118 embodies the information from leads 120, 121, 122, 123, 124, and 125.

Lead 120 is associated with a switch 130 sensing the open or closed position of the driver's door of the vehicle; lead 121 is associated with a switch 132 sensing the presence or absence of a driver on the driver's seat of the vehicle; lead 122 senses the open or closed condition of the ignition switch 134 of the vehicle; leads 123 and 124 are connected to the negative and positive terminals of the vehicle battery 135 with a suitable fuse 136 in lead 123; and lead 125 is connected to a speed sensor 137 which provides information with respect to the instantaneous speed which the vehicle is traveling. The invention electric shift assembly is delivered to the vehicle manufacturer in the form of power module 34 and control module 36. During the assembly of the vehicle, the power module 34 is mounted on the transmission housing 32 in coupling relation to mode select

shaft 30 and the control module 36 is mounted in the instrument panel 10, whereafter plug ^" 90 is plugged into plug 114 and plugs 110 and 118 are plugged into control module 36 to complete the assembly of the electric shift assembly.

The mounting of power module 34 on the transmission housing is accomplished simply by positioning the lower end 52a of reduction shaft 52 over the upper end 30a of mode select shaft 30 and passing bolts 54 downwardly through bores 46d and spacers 56 for threaded engagement with tapped bores 32a in transmission housing 32.

Installation of control module 36 in instrument panel 10 is affected simply by moving the control module from the rear of the panel into the opening 10a and fastening the module in place by the use of fasteners 96 or the like. Following the plugging of plug 90 into plug 114 and the plugging of plugs 110 and 118 into connector terminals 106 and 108, the system is operational for shifting the transmission. In use, various input signals, such as described above and illustrated in Figure 7, are supplied to a logic chip 141, which may be a programmable logic array or a gate array. Logic chip 141 is configured to receive these input signals and generate the necessary drive signals to motor 38 via a buffer 142 for providing the selection of the desired gear. The various input signals are formed into a set of logic signals.

Logic chip 141 serves to compare the inputs indicating the depressed push button with the inputs

indicating the present gear. If they differ, then logic chip 141 generates an output signal to ^" motor 38 to rotate the motor until the present gear matches the selected gear. This process includes an indication of which shifts are upshifts and which are downshifts according to Boolean equations.

As soon as the instantaneous encoder signal transmitted by pickup device 76 matches the signal generated by the specific depressed push button, the comparator logic of control module 36 functions to deenergize and brake the motor so that the mode select shaft 30, and thereby the transmission, is stopped precisely in the selected shift position.

The manner in which the various input signals are formed into a set of logic signals, the specific Boolean equations employed, and the manner in which the control system functions to receive an input or request signal, compare it to the present transmission state signal, and suitably energize the motor to shift the transmission to the desired state, are explained in further detail in U.S. Patent Nos. 4,841,793, 4,790,204, 4,817,471, and U.S. application Serial No. 311,982 filed February 16, 1989, all assigned to the assignee of the present application.

The circuit diagram seen in Figure 7 further includes a starter motor circuit 150 and a backup light circuit 152.

Starter motor circuit 150 includes a starter enable output 154, a lead 156 connected between the starter enable output 154 and the logic submodule 36b, and a lead

158 connected between the starter enable output 154 and the starter motor 160 of the motor vehicle.

Backup light circuit 152 includes a backup light drive 162, a lead 164 connected between the backup light drive 162 and logic submodule 36b, and a further lead 166 connected between backup drive 162 and the backup lamp 168 of the motor vehicle.

With reference now to Figure 8, lead 156 is connected to an open collector output 170 positioned within logic submodule 36b and connected to logic chip 141. Starter enable output 154 includes a first relay 172 and a second relay 174. The coil 174 of first relay 172 is connected to lead 156 and to the positive battery terminal, and the contacts 176 of first relay 172 are connected at one side to a lead 178 extending from the ignition switch 134 of the motor vehicle.

The coil 180 of second relay 174 is connected to the other side of the contacts 176 of first relay 172 and to ground and the contacts 182 of second relay 174 are connected between battery positive and lead 158 to starter motor 160.

Logic chip 141, upon receipt of a neutral or park signal from encoder assembly 172 acts through open collector output 170 and through coil 174 of relay 172 to enable the starter motor circuit and, specifically, act to close contacts 176 so that upon movement of ignition switch 134 to a start position a circuit is completed through coil 180 of relay 174 to close contacts 182 of relay 174 to provide a high current circuit from the positive battery

terminal to starter motor 160 via lead 158 to allow starting of the vehicle. The described circuitry operates to maintain the starter motor circuit enabled for so long as chip 141 continues to receive a neutral or a park signal from the encoder assembly 72. As soon as the encoder assembly indicates a transmission state other than park or neutral, the logic submodule operates to deenergize the relay 174 and disenable the vehicle starter motor circuit. Backup light drive 162 includes a relay 190. The coil 192 of relay 190 is connected via lead 164 to an open collector output 194 within logic submodule 36b and connected to logic chip 141. The other side of coil 192 is connected to positive battery. The contacts 194 of relay 190 are connected between positive battery and lead 166. When logic chip 141 receives a reverse signal from encoder assembly 72 the chip operates through open collector output 194 and via lead 164 to energize coil 192 of relay 190 and thereby close contacts 194 to close a circuit between the battery and backup lamp 168 via lead 166. The logic chip continues to energize relay 190 and maintain contacts 194 in a closed position so long as a reverse transmission state signal is being received from encoder assembly 72 and, conversely, acts to deenergize relay 190 and open contacts 194, thereby breaking the circuit to the backup lamp, when the encoder input to logic chip 141 indicates a transmission state other than reverse.

The control apparatus seen in Figures 9-12 is generally similar to the control apparatus of the Figures

1-8 embodiment and like reference numerals are used to

indicate identical or comparable elements in the two embodiments. The logic submodule 36b of the control model 36 of the Figures 9-12 embodiment includes a logic control unit or chip 141, a desired gear encoder 200, a speed sensor 137, and an analog-to-digital speed decoder 204. The specific output from the push-button module 36a, as determined by the specific button 100 depressed by the vehicle operator, is transmitted electrically to desired gear encoder 200 which functions in known manner to generate an electric signal for transmission to logic chip 141 with a specific transmitted signal corresponding in encoded language to the specific gear selected by operator depression of the specific push-button 100 of the push¬ button module. Speed sensor 137 functions in known manner to provide analog information with respect to the instantaneous speed of the vehicle and analog-to-digital speed decoder 204 receives the analog input from speed sensor 137 and generates a plurality of desired speed signals for example, MPH3, MPH7, MPH20 and MPH30 for transmission to the logic chip 141. Analog-to-digital speed decoder 204 produces each speed signal MPH3, MPH7, MPH20 and MPH30 as a digital signal of a first type when the analog information from speed sensor 137 indicates a vehicle speed less than a corresponding predetermined vehicle speed and has a digital signal of the opposite type when the analog information from speed sensor 137 indicates a vehicle speed greater than the corresponding predetermined vehicle speed. The plurality of speed

signals generated by speed decoder 204 provide a plurality of threshold vehicle speed signals for use by the logic control unit in deciding whether a requested shift is allowable in view of the instantaneous speed of the vehicle. The selected threshold vehicle speed signals will of course vary depending upon the particular vehicle application.

In the general operation of the electric control system of the Figures 9-12 embodiment, a signal from the operator originated by depression of the appropriate push¬ button 100 of the push-button module 36a is relayed to the desired gear encoder 200 and then to the logic chip 141 which compares the desired shift signal to the present gear encoder signal as provided from encoder assembly 72 via lines 88 and 112 and, if the desired signal differs from the present signal and the threshold speed signal MPH3, MPH7, MPH20 and MPH30 being supplied by speed decoder 137 indicates that the desired shift is permissible, transmits a signal through lines 112 and 86 to motor 38 to rotate the motor in a clockwise or a counter-clockwise direction and thereby rotate the associated mode select shaft of the transmission to shift the transmission to the desired position. Further details of the manner in which push¬ button module 34, power module 36, logic chip 141, speed sensor 137, speed decoder 204, and desired gear encoder 200 coact to achieve the shift in the transmission in accordance with the requested signals as provided by operator input to the push-button module are disclosed in previously referred to U.S. Patent No. 4,817,471.

The motor vehicle, in accordance with standard practice, includes ignition switch 134 and logic chip 141, as more fully explained in U.S. Patent No. 4,817,471 functions to shift the transmission to PARK automatically in response to movement of the ignition switch from an ON or activated position to an OFF or deactivated position and so long a the threshold speed signal being supplied at that instant by speed decoder 137 indicates that such a shift is permissible, that is indicates that the vehicle speed is below 3 miles per hour.

The control apparatus of the Figures 9-12 embodiment also includes means to continuously display the instantaneous state or position of the transmission at all appropriate times and in a manner to clearly apprise the operator of the state or position of the transmission. The transmission display feature of the invention is provided by a present gear indicator 206, a present gear indicator drive module 208, and an instrument panel display 210 preferably of the vacuum florescent type. Present gear indicator drive module 208 is connected to logic chip 141 by a lead 212 and is in turn connected to present gear indicator module 206 by a lead 214. A lead 216 connects instrument panel VF display 210 to present gear indicator module 206 and a lead 218 connects the ignition switch 134 to logic chip 141. Lead 218 provides an ignition ON signal and specifically provides a positive signal at any time that the key is inserted in the ignition switch and the ignition switch moved to an ON or activated position.

Present gear indicator module 206 is physically positioned adjacent push-button module 36a and includes a plurality of enunciator lamps 220 corresponding in number to the push-button 100 of the push-button module 36a with a lamp 220 positioned immediately adjacent each of the push-buttons 100 of the push-button module. Push-buttons 100 are preferably formed of a translucent material and light means, forming a part of the usual instrument panel lighting circuit, are arranged behind the push-buttons so that the push-buttons are illuminated, at a level depending upon the position of the usual instrument panel light intensity adjuster, upon movement of the ignition to an activated position.

In the alternate arrangement seen in Figure 12, the lamps 220 are positioned behind the respective corresponding push-buttons 100, the push-buttons are constructed of a translucent material so that the lamps, when energized, cause the corresponding push-buttons to be lighted, and the lamps 220 are arranged in the usual instrument panel lighting circuit. With this alternative arrangement, all of the lamps are illuminated at a relatively low level as a part of the instrument panel lighting whenever the ignition switch is in an activated position and the lamp corresponding to the instantaneous position of the transmission is illuminated at a high intensity level to brightly illuminate the push-button corresponding to the present transmission position and provide a clear enunciation of the present transmission position.

During normal vehicle operation, present gear indicator driver module 208 receives an appropriate coded signal from logic chip 141 via lead 212 representative of the present transmission position, as provided by encoder assembly 72, and transmits an appropriate driver signal via lead 214 to present gear indicator module 206 to light the appropriate lamp 220 corresponding to the instantaneous position of the transmission, or to increase the light intensity of the appropriate push-button in the alternative arrangement of Figure 12. At the same time, present gear indicator driver module 208 transmits a drive signal via lead 214 and lead 216 to instrument panel display 210 which functions to display in letter symbols the instantaneous position of the transmission in a window 222 provided in the instrument panel of the vehicle directly in the line of sight of the vehicle operator. That is, if the vehicle transmission is presently in PARK the lamp .220 adjacent the PARK push-button will be lit and the word "PARK" will be displayed in the window 222. When the operator enters the vehicle via door 224 and moves the ignition switch 134 to an ON or an activated position, a signal is transmitted to logic chip 141 via lead 218 and thence via lead 212 to present gear indicator drive module 208 to generate an appropriate drive signal via lead 214 to present gear indicator module 206 to light the appropriate light 220 and generate a drive signal in lead 216 to display the appropriate letter signals in window 222, thereby to indicate the instantaneous position of the transmission. Since, as previously indicated, logic

chip 141 functions in response to movement of the ignition key to the OFF position to automatically shifts the transmission to the PARK position, the transmission will be in the PARK position as the operator returns to the vehicle and accordingly the lamp 220 opposite the PARK push-button will be lit and the instrument panel display 210 will display the word "PARK."

In further response to operator movement of ignition switch to an ON or activated position, a signal is transmitted via lead 226 to present gear indicator 206 to light all of the lamps 220, thereby providing a system check that all of the lamps are operational. The lamps 220 continue to be lit for a time determined by a timer 228 in line 226 whereafter, as the timer times out, the signal via lead 226 is terminated but the lamp 220 corresponding to the present gear position, for example PARK, continues to be illuminated via lead 214 and the VF display in window 222, for example PARK, continues in effect via leads 214 and 216. Timer 228 may for example time out one second after the ignition is moved to the ON position thereby providing the operator with a one second system check to insure that all lamps 220 are operational whereafter the system automatically reverts to the mode in which the instantaneous position of a transmission is indicated by illumination of the appropriate lamp 220 and the instantaneous position of the transmission continues to be displayed in letter symbol form in window 222.

It will be understood that, in the alternative arrangement of Figure 12, all of the push-buttons will be

brightly illuminated in response to movement of the ignition switch to an activated position, whereafter, following timing out of the timer 228, only the push-button corresponding to the present position of the transmission will remain brightly illuminated and the other push-buttons will revert to a low level illumination as determined by the setting of the instrument panel lighting circuit.

The invention electric control apparatus will be seen to provide a compact, efficient and inexpensive mechanism for providing automatic shifting of a transmission in response to operator input, for providing a neutral START signal to enable the starter motor circuit, and for providing a reverse signal to energize the back-up lamp circuit. Further, the invention transmission display system will be seen to provide a clear and positive display to the vehicle operator at all times of the instantaneous position of the transmission both by virtue of the particular lamp 220 that is lit in the present gear indicator module 206 and by virtue of the specific legend displayed in the instrument panel display 210, and further functions each time the vehicle is started to provide a system check to insure the operator that the display system is working properly.

Whereas preferred embodiments of the invention has been illustrated and described in detail, it will be apparent that various changes may be made in the disclosed embodiments without departing from the scope or spirit of the invention.