Control system for automatic transmission

• US 5,707,317 A
• Filed: 09/20/1996
• Issued: 01/13/1998
• Est. Priority Date: 09/21/1995
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kaigawa, Masato, Tabata, Atsushi
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US08/716,861
• Time in Patent Office: 480 Days
• Field of Search: 477/109
• US Class Current: 477/109
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16H 59/18 dependent on the position of the accelerator pedal
• CPC Class Codes: F16H 59/24 dependent on the throttle opening
• CPC Class Codes: F16H 59/72 dependent on oil characteristics, e.g. temperature, viscosity
• CPC Class Codes: F16H 59/78 Temperature
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: F16H 63/502 for smoothing gear shifts

Abstract

A control system for an automatic transmission connected to an engine, in which a fundamental throttle opening is set with a predetermined delay characteristic from a depression stroke of an accelerator pedal and in which a present throttle opening is set with an inevitable delay and with a selective delay control for the fundamental throttle opening. A gear stage to be set in the automatic transmission is decided on the basis of the fundamental throttle opening, and an oil pressure to be fed to a frictional engagement unit for achieving a gear stage is set on the basis of the present throttle opening.

Claims

1. A control system for an automatic transmission connected to an engine, in which a fundamental throttle opening is set with a predetermined delay characteristic from a depression stroke of an accelerator pedal and in which a present throttle opening is set with an inevitable delay and with a selective delay control for the fundamental throttle opening, comprising:

shift decision means for deciding a gear stage to be set in said automatic transmission, on the basis of said fundamental throttle opening; and

oil pressure adjusting means for setting an oil pressure to be fed to a frictional engagement unit for achieving a gear stage, on the basis of said present throttle opening.

2. A control system for an automatic transmission according to claim 1, further comprising:

control condition decision means for deciding whether or not a predetermined condition is satisfied; and

delay control means for setting said present throttle opening with a predetermined delay from said fundamental throttle opening if said control condition decision means decides the satisfaction of said condition,

wherein said oil pressure adjusting means sets the oil pressure to be fed to said frictional engagement means, on the basis of said present throttle opening, only if said delay control means controls said present throttle opening with a predetermined delay from said fundamental throttle opening.

3. A control system for an automatic transmission according to claim 2,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if a shift range capable of setting all forward gear stages is selected in said automatic transmission.

4. A control system for an automatic transmission according to claim 2,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if either the temperature of said engine or the oil temperature of said automatic transmission is over a predetermined level.

5. A control system for an automatic transmission according to claim 2,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if the vehicle speed is over a predetermined level.

6. A control system for an automatic transmission according to claim 2, further comprising:

another oil pressure adjusting means for setting the oil pressure to be fed to said frictional engagement means, on the basis of said fundamental throttle opening unless the control by said delay control means is executed.

7. A control system for an automatic transmission according to claim 1, further comprising:

torque down control means for lowering the output torque of said engine temporarily while the shift control in said automatic transmission is being executed,

wherein said oil pressure adjusting means sets the oil pressure to be fed to said frictional engagement means, on the basis of said present throttle opening unless said torque down control means executes a control to lower the output torque of said engine.

8. A control system for an automatic transmission according to claim 1, further comprising:

torque down control means for lowering the output torque of said engine temporarily while the shift control in said automatic transmission is being executed; and

another oil pressure adjusting means for setting the oil pressure to be fed to said frictional engagement means, if the engine torque is lowered during the shift, to the pressure which is prepared by correcting the pressure set on the basis of said present throttle opening in accordance with the lowering control amount of the engine torque.

9. A control system for an automatic transmission according to claim 2, further comprising:

torque down control means for lowering the output torque of said engine temporarily while the shift control in said automatic transmission is being executed,

wherein said oil pressure adjusting means sets the oil pressure to be fed to said frictional engagement means, on the basis of said present throttle opening unless said torque down control means executes a control to lower the output torque of said engine.

10. A control system for an automatic transmission according to claim 9,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if a shift range capable of setting all forward gear stages is selected in said automatic transmission.

11. A control system for an automatic transmission according to claim 9,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if either the temperature of said engine or the oil temperature of said automatic transmission is over a predetermined level.

12. A control system for an automatic transmission according to claim 9,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if the vehicle speed is over a predetermined level.

13. A control system for an automatic transmission according to claim 9, further comprising:

another oil pressure adjusting means for setting the oil pressure to be fed to said frictional engagement means, on the basis of said fundamental throttle opening unless the control by said delay control means is executed.

14. A control system for an automatic transmission according to claim 2, further comprising:

torque down control means for lowering the output torque of said engine temporarily while the shift control in said automatic transmission is being executed; and

another oil pressure adjusting means for setting the oil pressure to be fed to said frictional engagement means, if the engine torque is lowered during the shift, to the pressure which is prepared by correcting the pressure set on the basis of said present throttle opening in accordance with the lowering control amount of the engine torque.

15. A control system for an automatic transmission according to claim 14,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if a shift range capable of setting all forward gear stages is selected in said automatic transmission.

16. A control system for an automatic transmission according to claim 14,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if either the temperature of said engine or the oil temperature of said automatic transmission is over a predetermined level.

17. A control system for an automatic transmission according to claim 14,

wherein said control condition decision means includes means for deciding the satisfaction of said condition if the vehicle speed is over a predetermined level.

18. A control system for an automatic transmission according to claim 14, further comprising:

another oil pressure adjusting means for setting the oil pressure to be fed to said frictional engagement means, on the basis of said fundamental throttle opening unless the control by said delay control means is executed.

19. A control system for an automatic transmission according to claim 1,

wherein said oil pressure adjusting means includes means for adjusting the oil pressure of said frictional engagement means to be applied at the time of a clutch-to-clutch downshift.

20. A control system for an automatic transmission according to claim 2, wherein said oil pressure adjusting means includes means for adjusting the oil pressure said frictional engagement means to be applied at the time of a clutch-to-clutch downshift.