Automatic transmission control system

• US 5,823,052 A
• Filed: 03/31/1997
• Issued: 10/20/1998
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: Nobumoto, Hidetoshi
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US08/834,820
• Time in Patent Office: 568 Days
• Field of Search: 74/335, 701/52
• US Class Current: 74/335
• CPC Class Codes: F16H 2037/088 Power split variators with summing differentials, with the input of the CVT connected or connectable to the input shaft
• CPC Class Codes: F16H 2059/0239 Up- and down-shift or range or mode selection by repeated movement mechanical step by step selection devices F16H63/14
• CPC Class Codes: F16H 2061/6615 Imitating a stepped transmissions
• CPC Class Codes: F16H 2061/6616 the shifting of the transmission being manually controlled
• CPC Class Codes: F16H 2061/6643 dependent on driver's choice
• CPC Class Codes: F16H 37/086 CVT using two coaxial friction members cooperating with at least one intermediate friction member
• CPC Class Codes: F16H 59/0204 for automatic transmissions with means for range selection and manual shifting, e.g. range selector with tiptronic
• CPC Class Codes: F16H 59/06 the ratio being infinitely variable
• CPC Class Codes: F16H 61/6648 controlling of shifting being influenced by a signal derived from the engine and the main coupling
• CPC Class Codes: Y10T 74/19251 Control mechanism

Abstract

A toriydal type of automatic transmission is changeable between an automatic shift mode and a manual shift mode in which a shift up switch or a shift down switch is operated. The automatic transmission in the manual shift mode is shifted down by one step when the shift down switch is operated and shifted up by two step when the shift up switch is operated, so that the transmission gear ratio changes at a rate smaller during a manual down shift than during a manual up shift.

Claims

1. A control system for controlling a gear ratio of an automotive automatic transmission changeable between an automatic shift mode and a manual shift mode, said automatic transmission control system comprising:

gear ratio control means for controlling a change of the gear ratio to shift the automatic transmission to a desired gear;

manually operated shift up means for causing said gear ratio control means to make the gear ratio lower to shift the automatic transmission up in said manual shift mode when said shift up means is continuously operated;

manually operated shift down means for causing said gear ratio control means to change the gear ratio higher to shift the automatic transmission down in said manual shift mode when said shift down means is continuously operated; and

a control means for controlling said gear ratio control means to make a change rate of the gear ratio lower when said shift down means is continuously operated than when said shift up means is continuously operated.

2. An automatic transmission control system as defined in claim 1, wherein said control means detects a duration of continuous operation of each of said shift up means and said shift down means, and controls said gear ratio control means to make said change rate higher when said duration of continuous operation is longer than a specified time than when said duration of continuous operation is shorter than said specified time.

3. An automatic transmission control system as defined in claim 2, wherein said control means controls said gear ratio control means to change said change rate so as to change the gear ratio to a gear ratio for a highest available gear at once when said duration of continuous operation of said shift up means is longer than said specified time.

4. An automatic transmission control system as defined in claim 1, wherein said control system controls said gear ratio control means to make said change rate higher when a gear prior to changing said change rate is higher than when said gear is lower.

5. An automatic transmission control system as defined in claim 1, wherein said control means keeps said gear ratio control means from changing said change rate when said shift up means and said shift down means are coincidentally operated.

6. An automatic transmission control system as defined in claim 1, wherein said automatic transmission is of a continuously variable type.

7. A control system for controlling a gear ratio of an automotive automatic transmission changeable between an automatic shift mode and a manual shift mode, said automatic transmission control system comprising:

gear ratio control means for controlling a change of the gear ratio in accordance with magnitude of an electric signal to shift the automatic transmission to a desired gear;

manually operated shift up means for making the gear ratio lower to shift the automatic transmission up in said shift mode when said shift up means is continuously operated;

manually operated shift down means for making the gear ratio higher to shift the automatic transmission down in said shift mode when said shift down means is continuously operated; and

control means for controlling said electric signal magnitude so that said gear ratio change means changes the gear ratio at a change speed lower when said shift down means is operated than when said shift up means is operated.

8. An automatic transmission control system as defined in claim 7, wherein said control means detects a duration of continuous operation of each of said shift up means and said shift down means, and makes said electric signal magnitude greater as said duration of continuous operation becomes longer.

9. An automatic transmission control system as defined in claim 7, wherein said control means detects a duration of continuous operation of each of said shift up means and said shift down means, and makes said electric signal magnitude smaller as said duration of continuous operation becomes shorter.