Electronic control for automatic transmission

Claim 2

An automatic transmission system for a vehicle having an engine with a throttle valve and an automatic transmission unit with an input shaft, an output shaft and a speed changing gear unit interconnected therebetween having brake and clutch means for establishing a plurality of speed gear'ratios, comprising: means for detecting an operating condition of said engine and said vehicle; a memory in which is stored data representing a plurality of speed change modes for effecting engine braking of different operating characteristics; a mode selecting circuit responsive to said detected operating condition to select the stored data representing one of said speed change modes; and a hydraulic actuating unit comprising a plurality of shift valves and corresponding solenoids for activating said shift valves in response to the data selected by said mode selecting circuit to control said brake and clutch means to select one of said gear ratios corresponding to the selected speed change mode.

Claim 3

An automatic transmission system as claimed in calim 1, wherein said memory includes data representing a first engine brake mode for effecting engine braking with low-to-medium speed gear at a high vehicle speed and a second engine brake mode for effecting engine braking with low-to-medium speed gear with the throttle valve being closed at a medium-to-high vehicle speed.

Claim 4

An automatic transmission system as claimed in claim 1, wherein said means for detecting an operating condition of said vehicle and said engine comprises a vehicle speed sensor and a throttle opening sensor, and wherein said stored data representing each of said speed change modes is sotred in said memory in a matrix of rows and columns corresponding to a coordinate system in which outputs of said throttle opening sensor are plotted as a function of outputs of said vehicle speed sensor.

Claim 5

An automatic transmission system as claimed in claim 3, further comprising circuit means converting the data read out of said memory into signals for application to said solenoids in accordance with said detected throttle opening and said vehicle speed.

Claim 6

An automatic transmission system as claimed in claim 4, wherein said means for detecting an operating condition of said vehicle and said engine further comprises: means for detecting the rate at which said throttle valve is opened to generate a first upshift command signal when the detected rate is higher than a predetermined value; means for detecting when said vehicle is moving uphill at a grade higher than a predetermined value or when said vehicle is moving downhill to generate a second upshift command signal; and means for detecting when the detected throttle opening is maintained for a predetermined period to generate a downshift command signal, said mode selecting circuit being responsive to said first and second upshift command signals and to said downshift command signal to selectively read the data representing one of said first and second engine brake modes out of said memory into said conversion circuit means.

Claim 7

An automatic transmission system as claimed in claim 5, wherein said operating condition detecting means further comprises means for detecting the position of a gear shift lever for applying a first signal to said mode selecting circuit indicating that the gear shift lever is in a drive range and applying a second signal indicative of a said detected gear position to said conversion circuit means.

Claim 8

An automatic transmission system as claimed in claim 6, wherein said conversion circuit means is responsive to said detected vehicle speed and said detected throttle opening.

Claim 9

An automatic transmission system as claimed in claim 1 or 2; wherein said memory further including data representing a plurality of gear engaging modes corresponding to said speed change modes for reducing the amount of shock which occurs during speed changes, and wherein said mode selecting circuit is arranged to select one of said gear engaging mode data in correspondence to the selected speed change mode data.

Claim 10

An automatic transmission system as claimed in claim 8, wherein said means for detecting an operating condition of said vehicle and said engine comprises a vehicle speed sensor and a throttle opening sensor, and wherein said stored data representing said gear engaging modes is stored in said memory in a matrix of rows and columns corresponding to a coordinate system in which outputs of said throttle opening sensor are plotted as a function of outputs of said vehicle speed sensor.

Claim 11

An automatic transmission system as claimed in claim 1 or 2, wherein said vehicle further includes an automatic drive system, and wherein said memory further includes data representing a speed change mode associated with said automatic drive system, further comprising means for detecting when said automatic drive system is operating and a preferential circuit for reading the last-mentioned data out of said memory in preference over input signals supplied to said mode selecting circuit.

Claim 12

An automatic transmission system as claimed in claim 1 or 2, wherein said memory further includes data representing the locking of said output shaft, and wherein said operating condition.detecting means includes means for detecting when said vehicle is in the process of deceleration to a standstill for supplying said mode selecting circuit with a signal for reading the-last mentioned data out of said memory to cause said clutch and brake means to lock said vehicle axle.

Claim 13

An automatic transmission system as claimed in claim 11, further comprising a brake assembly comprising: a shaft having a manual control knob secured to an upper end of said shaft rotatably and longitudinally movaly disposed in a guide member, said shaft having a first wire leading from the other end thereof to a parking lock mechanism of said vehicle to cause it to operate exclusively in response to an upward movement of said shaft and a second wire leading to a side brake system of the vehicle to cause it to operate exclusively in response to a rotational movement of the shaft; and spring-biasing means for urging said shaft to a predetermined angular position and to a predetermined longitudinal position.

Claim 14

An automatic transmission as claimed in claim 1 or 2, wherein said solenoids are arranged so that when all of said solenoids are de-energized said shift valves cause said clutch means to be shifted to a predetermined speed range, further comprising a fail-safe logic circuit connected to input circuits of said solenoids for detecting a predetermined combination of the operating states of the solenoids for disconnecting the supply of power to said solenoids, whereby in the event of a failure in the input circuits of said solenoids said speed gear ratio is automatically shifted to said predetermined speed range.

Claim 15

An automatic transmission system as claimed in claim 13, wherein said logic circuit includes a coincidence gate connected to the input circuits of said solenoids to detect said predetermined combination of their operating states, timing circuit means for detecting when the output of said coincidence gate is present for a predetermined period of time, and a bistable circuit responsive to the output of said timing circuit means for generating an inhibit signal and responsive to an externally applied signal to generate a noninhibit signal, and switching means for supplying a current from a power source to said solenoids in response to said noninhibit signal and shutting off the current supply in response to said inhibit signal.

Claim 16

An automatic transmission system as claimed in claim 14, wherein said input circuits of said solenoids include a computer which controls the supply of currents to said solenoids from said power source in response to the selected data, so that in the event of a failure in said computer, said solenoids are all de-energized to shift the speed gear ratio to said predetermined speed range.

Claim 17

An electronic control cirucit for automatic transmission comprising: a memory in which is stored a set of data representing a plurality of transmission shift patterns in a matrix of rows and columns, each of said patterns describing a relationship between the opening of a throttle valve of an engine and the speed of a vehicle, each of said shift patterns corresponding to a different operating characteristic of engine braking; a throttle opening sensor; a vehicle speed sensor; means for detecting an operating condition of the vehicle in response to said sensors; means for selectively reading the stored data representing one of the transmission shift patterns in response to said detected operating vehicle condition; a plurality of solenoids;. a hydraulic actuating circuit having a plurality of shift valves in communication with said transmission through hydraulic circuits and respectively movable in response to the operation of said solenoids for controlling said transmission to a shift pattern represented by the data read out of said memory; and means for generating solenoid activating signals from said read-out data as a function of the outputs of said sensors for application to said solenoids.

Claim 18

An electronic control cirucit for automatic transmission comprising: a memory in which is stored a set of data representing a plurality of transmission shift patterns in a matrix of rows and columns, each of said patterns describing a relationship between the opening of a throttle valve of an engine and the speed of a vehicle, each of said shift patterns corresponding to a different operating characteristic of engine braking; a throttle opening sensor; a vehicle speed sensor; means for detecting an operating condition of the vehicle in response to said sensors; means for selectively reading the stored data representing one of the transmission shift patterns in response to said detected operating vehicle condition; a plurality of solenoids;. a hydraulic actuating circuit having a plurality of shift valves in communication with said transmission through hydraulic circuits and respectively movable in response to the operation of said solenoids for controlling said transmission to a shift pattern represented by the data read out of said memory; and means for generating solenoid activating signals from said read-out data as a function of the outputs of said sensors for application to said solenoids.

Claim 19

An electronic control circuit as claimed in claim 16, wherein said memory includes data representing a first engine brake mode for effecting engine braking with low-to-medium speed gear at a high vehicle speed and a second engine brake mode for effecting engine braking with low-to-medium speed gear with the throttle valve being closed at a medium-to-high vehicle speed.

Claim 20

An electronic control circuit as claimed in claim 16 or.l7, further comprising: an acceleration rate sensor for generating a signal indicative of the rate of acceleration of said vehicle; a grade sensor for generating a signal indicative of the grade of a terrain on which said vehicle is moving; a load sensor for generating a signal indicative of the amount of load on said vehicle; means receptive of said acceleration rate signal, grade signal and said load signal for generating an upshift command signal; a coasting drive sensor for generating a downshift command signal when said vehicle is running at a constant' speed for a predetermined period; and said reading means is responsive to said upshift and downshift command signals to read out the stored data.

Claim 21

An electronic control circuit as claimed in claim 16, further comprising means for detecting the position of a shift lever of said vehicle, wherein said means for generating solenoid activating signals is responsive to said shift lever position detecting means.

Claim 22

An electronic control circuit as claimed in claim 16, wherein said memory further includes data representing a plurality of transmission shift patterns each describing a relationship between the opening of the throttle valve and the vehicle speed for a different gear engaging characteristic, and wherein said reading means includes means for selectively reading the stored data representing one of said transmission.shift patterns of gear engaging characteristics out of said memory in response to said detected vehicle operating condition.

Claim 23

An electronic control circuit as claimed in calim 16 or 20, further comprising an automatic drive sensor, wherein said memory further includes data representing a plurality of transmission shift patterns each describing a relationship between the throttle opening and the vehicle speed for a different automatic drive characteristic, and wherein said reading means includes means for selectively reading the stored data representing one of said transmission shift patterns of automatic drive characteristic out of said memory in response to said detected vehicle operating condition.

Claim 24

An electronic control circuit as claimed in claim 19, further comprising a brake pedal sensor for generating a signal when the brake pedal of the vehicle is depressed, and wherein said means for generating solenoid activating signals further comprises means responsive to said brake pedal signal, said shift lever position signal, and the outputs of said throttle opening and vehicle speed sensors to activate said solenoids such that an output shaft of said transmission is locked.