Interrelated power delivery controls – including engine control – Transmission control – Transmission controlled by engine
Reexamination Certificate
2001-01-18
2003-01-07
Estremsky, Sherry (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Transmission controlled by engine
C477S079000, C477S124000, C477S906000
Reexamination Certificate
active
06503172
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a control unit and a control method of an automatic transmission for controlling a hydraulic pressure used for a shift in the automatic transmission of an automotive vehicle, and an automotive vehicle having the control unit mounted thereon.
As this kind of control method in accordance with the prior art, for example, there is a structure described in Japanese Patent Unexamined Publication No. 9-280362. This conventional control method is structured such as to at first start an engagement of a fixed side friction device when a shift command signal is generated and next start a disengage of a disengage side friction device when recognizing a disengage timing of the disengage side friction device. Further, the disengage timing of the disengage side friction device is recognized by detecting a torque phase on the basis of a longitudinal acceleration signal of a vehicle. Here, the torque phase means a period at which a number of rotation of a turbine is not reduced and only a torque of an output shaft in the transmission is changed in the case of paying attention to a time change of the torque of the output shaft in the transmission. Further, when recognizing a disengage timing (a torque phase) of the disengage side friction device on the basis of the longitudinal acceleration signal of the vehicle, an elapsed time after the shift command signal is generated is measured, the elapsed time when the disengage timing is recognized is compared with a predetermined elapsed time and a disengage of the disengage side friction device is started for the first time when the former elapsed time is greater than the latter elapsed time, whereby an early disengage due to an erroneous recognition of the disengage timing during a rough road travelling or the like is prevented and a blowing-up of a number of rotation of the turbine is prevented.
In accordance with the control method described in Japanese Patent Unexamined Publication No. 9-280362, as mentioned above, since the disengage side friction device is disengaged for the first time when the elapsed time at which the disengage time is recognized becomes greater than the predetermined elapsed time, it is possible to prevent an early disengage due to an erroneous recognition of the disengage timing during the rough road travelling. However, in accordance with the control method described in Japanese Patent Unexamined Publication No. 9-280362, in the case that the disengage timing can not be recognized due to the rough road travelling, both of the fixed side friction device and the disengage side friction device are fixed (tied up), so that there is generated a problem that not only the shift characteristic is deteriorated but also the friction device (a clutch) is promoted to be broken.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide a control unit and a control method of an automotive vehicle which securely prevent a tie-up due to a miss-recognition of the disengage timing of the disengage side friction device and realize a control of accurately and reliably shifting the clutch, and an automotive vehicle having the control unit mounted thereon.
A second object of the present invention is to provide a control unit and a control method of an automotive vehicle which securely prevent an early disengage and a tie-up due to an erroneous recognition and a miss-recognition of the disengage timing of the disengage side friction device and realize a control of accurately and reliably shifting the clutch.
(1) In order to achieve the first object mentioned above, in accordance with the present invention, there is provided a control unit of an automatic transmission having pressure adjusting command generating means which executes a shift by engaging and disengaging a predetermined friction device in an automatic transmission connected to an engine and adjusts a hydraulic pressure acting on the friction device at a time of the shift, comprising:
disengage timing recognizing means which recognizes a disengage timing of a disengage side friction device at a time of shifting the automatic transmission;
first disengage determining means which determines a disengage operation of the disengage side friction device on the basis of a result of recognition by the disengage timing recognizing means; and
second disengage determining means which forcibly determines a disengage operation of the disengage side friction device in the case that it is impossible to recognize the disengage timing in the disengage timing recognizing means,
wherein the pressure adjusting command generating means operates so as to disengage the disengage side friction device on the basis of determination of the first and second disengage determining means.
As mentioned above, the second disengage determining means is provided in addition to the first disengage determining means so as to forcibly determine the disengage operation of the disengage side friction device in the case that the disengage timing of the disengage side friction device can not be recognized in the disengage timing recognizing means, whereby the tie-up due to the miss-recognition of the disengage timing is securely prevented by forcibly disengaging the friction device even in the case that the disengage timing can not recognized, for example, due to the rough road travelling or the like, and an accurate and reliable clutch shifting control can be realized.
(2) Further, in order to achieve the second object mentioned above, in accordance with the present invention, there is provided a control unit of an automatic transmission having pressure adjusting command generating means which executes a shift by engaging and disengaging a predetermined friction device in an automatic transmission connected to an engine and adjusts a hydraulic pressure acting on the friction device at a time of the shift, comprising:
disengage timing recognizing means which recognizes a disengage timing of a disengage side friction device at a time of shifting the automatic transmission;
first disengage determining means which determines a disengage operation of the disengage side friction device on the basis of a result of recognition by the disengage timing recognizing means; and
second disengage determining means which forcibly determines a disengage operation of the disengage side friction device in the case that it is impossible to recognize the disengage timing in the disengage timing recognizing means,
wherein the pressure adjusting command generating means operates so as to disengage the disengage side friction device on the basis of determination of the first and second disengage determining means, and there is further provided disengage inhibiting means for inhibiting a disengage of the disengage side friction device for a predetermined period after the automatic transmission starts shifting.
As mentioned above, since the second disengage determining means is provided in addition to the first disengage determining means, the tie-up due to the miss-recognition of the disengage timing is securely prevented as mentioned in the item (1) mentioned above. Further, since the disengage inhibiting means is provided so as to inhibit to disengage the disengage side friction device for a predetermined period after the automatic transmission starts shifting, an early disengage is securely prevented even in the case that the disengage timing is erroneously recognized, for example, due to the rough road travelling or the like, and an accurate and reliable clutch shifting control can be realized.
(3) Further, in order to achieve the first object mentioned above, in accordance with the present invention, there is provided a control method of an automatic transmission having pressure adjusting command generating means which executes a shift by engaging and disengaging a predetermined friction device in an automatic transmission connected to an engine and adjusts a hydraulic pressure acting on the friction device at a time of the shift, comprisi
Minowa Toshimichi
Ochi Tatsuya
Crowell & Moring LLP
Estremsky Sherry
Hitachi , Ltd.
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