CONTROL SYSTEM FOR AUTOMOTIVE AUTOMATIC TRANSMISSION

• US 3,640,156 A
• Filed: 10/29/1969
• Issued: 02/08/1972
• Est. Priority Date: 10/30/1968
• Status: Expired due to Term

• Current Assignee: Hiroshisa Ichimura, Yoichi Mori
• Original Assignee: Hiroshisa Ichimura, Yoichi Mori
• Inventors: Mori, Yoichi, Ichimura, Hiroshisa
• Primary Examiner(s): McKeon, Arthur T.
• Application Number:
  US04/872,253
• Time in Patent Office: 832 Days
• Field of Search: 74/866,336,365,731,752
• US Class Current: 477/93
• CPC Class Codes: F16H 59/44 dependent on machine speed of the machine, e.g. the vehicle
• CPC Class Codes: F16H 59/66 Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 59/78 Temperature
• CPC Class Codes: F16H 61/0021 Generation or control of line pressure
• CPC Class Codes: F16H 61/0206 Layout of electro-hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/2807
• CPC Class Codes: Y10S 477/901 Control signal is slope

Abstract

An automatic transmission mechanism for an automotive vehicle in which the transmission governing factors such as the position of the speed selecting lever, position of the accelerator pedal and the throttle valve, engine speed, vehicle speed and road grade are measured by electric means and the signals thus obtained are continuously fed into an electronic control system for evaluation of the requirements from the transmission. The electronic control system sends signals to elements converting them into hydraulic pressure which actuates friction elements to change gear ratios of the transmission.

Claims

1. An automatic transmission for an automotive vehicle comprising at least one planetary gear set including actuable friction elements selectively hydraulically for obtaining different speed ratios;

hydraulic means supplying hydraulic pressure to said friction elements for actuation of said friction elements;

sensing means for sensing vehicle speed, engine speed, position of a speed selecting lever, position of an acceleration control member, and engine torque; and

electrical means responsive to said sensing means and controlling the operation of said hydraulic means for firstly causing a change of gear reduction ratio to take place at a level of vehicle speed which is higher the greater the displacement of the acceleration control member is and for secondly causing variation in the level of the hydraulic pressure in dependence on the engine torque and in dependence on the vehicle and engine speeds.

2. An automatic transmission of the planetary gear set type according to claim 1, wherein said sensing means includes vacuum level sensing means for sensing vacuum level in an intake manifold of an engine of the vehicle as a function of the engine torque.

3. An automatic transmission of the planetary gear set type according to claim 1, further comprising inclination-sensing means for sensing the longitudinal inclination of said vehicle, wherein said electrical means is responsive to said inclination-sensing means for raising the level of vehicle speed at which the change of gear reduction ratio is caused to take place both when the vehicle is ascending and when the vehicle is descending.

4. An automatic transmission of the planetary gear set type according to claim 1, further comprising temperature-sensing means for sensing engine temperature, wherein said electrical means is responsive to said temperature means for raising the level of vehicle speed at which the change of gear ratio is caused to take place when engine temperature is low.

5. An automatic transmission of the planetary gear set type according to claim 1, further comprising brake-sensing means for sensing brake operation of said vehicle, wherein said electrical means is responsive to said brake-sensing means for raising the level of vehicle speed at which shifting down is caused to take place when the brake operation is effected.

6. An automatic transmission of the planetary gear set type according to claim 1, comprising a torque converter, wherein said sensing means comprises first voltage-generating means for generating voltage proportional to the rotational speed of the output shaft of said engine, second voltage-generating means for generating voltage proportional to the rotational speed of the driven shaft of said vehicle, third voltage-generating means for generating voltage proportional to an angular position of the throttle valve of the carburetor of said engine, wherein said electrical means comprises an electrical circuit including an emergency switch, a starter switch, a manual lever operated selector switch selectively connectable to said emergency switch and to said starter switch, and electronic calculating means connected for reception of the voltage from first and second voltage-generating means and electric signals from said selector switch through said emergency switch for comparing the relative values of said received voltages and electrical signals and upon detecting a predetermined gear shift point, for developing a selective signal to initiate a gear shift for supplying a signal to a throttle valve controller independently of the position of said accelerator pedal, synchronizing the speed of sAid engine output shaft with the speed of said driven shaft, for developing a timer signal to cause a momentary pressure fall in said hydraulic pressure while said gear shift takes place, and for developing a signal for causing a selected engagement and disengagement of at least one of said friction members to effect said gear shift;

and wherein said hydraulic means comprises a regulator valve, a hydroelectronic converting means connected for reception of said timer signal and for the speed of a turbine shaft of said torque converter for supplying a hydraulic signal to said regulator valve;

electromechanical valve means responsive to said hydraulic pressure for causing actuation of at least one of said friction members, and solenoid valve means connected for reception of said timer signal for controlling the level of said hydraulic pressure while said gear shift takes place.

7. An automatic transmission of the planetary gear set type according to claim 6, wherein said electrical means comprises a low speed limit relay connected to said electronic calculating means and said throttle valve controller for resetting the position of said throttle valve when the engine speed is lower than a predetermined level.

8. An automatic transmission of the planetary gear set type according to claim 7, wherein at least one manually controllable low forward speed power train, at least two electronically controllable forward speed power trains and at least one manually controllable reverse power train are provided.

9. An automatic transmission of the planetary gear set type according to claim 8, wherein said emergency switch, when in emergency position, provides electrically a high forward speed power train while low and intermediate forward speed and reverse power trains are hydraulically provided.

10. An automatic transmission of the planetary gear set type according to claim 8, wherein said electronic calculating means develops a signal for changing the input/output ratio into a high forward speed power train when said vehicle is decelerated to a complete halt and the throttle valve is closed and a signal for changing said input/output ratio into a low forward speed power train when said throttle valve is opened by depressing said accelerator pedal, thereby avoiding vehicle creep during said halt but providing a high torque power train for easily starting said vehicle from said halt.

11. An automatic transmission of the planetary gear set type according to claim 8, wherein said friction elements comprises a second clutch having its drive portion connected to a turbine shaft of said torque converter and a driven portion, and a first brake;

and wherein said planetary gear set comprises a first planetary gear set including a first ring gear connected with said driven portion of said second clutch, a first sun gear and a plurality of first planet gears all of which are rotatably connected with a first carrier connected with said driven shaft and are also meshed with both said ring and sun gears, a second planetary gear set including a second sun gear integrally and axially connected with the sun gear of the first planetary gear set, a second ring gear connected with said driven shaft and a plurality of second planet gears all of which are connected with a second carrier and meshed with said second ring and sun gears, whereby a power train for a low speed ratio is provided for forward drive through the drive portion of said second clutch when the driven portion thereof is engaged with the drive portion thereof, the first ring gear of the first planetary gear set engaging with the drive portion of said second clutch connected with said turbine shaft, said first planet gears engaging with said first ring gear, said driven shaft being connected with said first planet gears through the first carrier connected therewith and said first brake providing a reaction element.