Interrelated power delivery controls – including engine control – Transmission control – Engine controlled by transmission
Reexamination Certificate
2000-04-21
2002-08-13
Bonck, Rodney H. (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Engine controlled by transmission
C477S111000
Reexamination Certificate
active
06432025
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cooperative control apparatus adapted to effect cooperative control of an automatic transmission incorporating a frictional coupling device which is engaged during power driving of the vehicle and released during coasting of the vehicle, and an engine which generates a power to drive the vehicle through the automatic transmission.
2. Discussion of the Related Art
There is known an automotive vehicle having an automatic transmission equipped with a frictional coupling device such as a one-way clutch, which is placed in its engaged state during power driving of the vehicle with an engine power and is placed in its released state during coasting of the vehicle so as to inhibit engine braking while a shift lever is placed in a drive position “D”, for instance. An example of such a vehicle is disclosed in JP-A-3-117763.
In an automotive vehicle having an automatic transmission equipped with a frictional coupling device as described above, there arises a large difference between the input speed of the automatic transmission and the synchronizing speed (which is the output speed multiplied by the currently established speed ratio of the automatic transmission), immediately after a shift-down action of the automatic transmission which takes place due to a drop of the running speed of the vehicle during a coasting run as a result of a releasing operation of the accelerator pedal toward its non-operated or engine-idling position. The large speed difference indicated above requires a relatively long time for the input speed of the automatic transmission to rise to the synchronizing speed when the accelerator pedal is again depressed to accelerate the vehicle. Accordingly, the frictional coupling device requires a long response time, namely, it takes a long time for the frictional coupling device to be engaged to transmit the engine power to the vehicle drive wheels, unfavorably resulting in deteriorated drivability of the vehicle as felt by the vehicle operator.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a cooperative control apparatus for controlling an automatic transmission and an engine of an automotive vehicle, which apparatus permits the engine power to be transmitted to the vehicle drive wheels in a relatively short time after an operation of the accelerator pedal to accelerate vehicle following a coasting run of the vehicle.
The above object may be achieved according to the principle of the present invention, which provides a cooperative control apparatus for controlling an automotive vehicle, so as to effect a cooperative control of an automatic transmission and a drive power source which produces an output to drive the vehicle through the automatic transmission, the automatic transmission incorporating a frictional coupling device which is engaged to place the automatic transmission in a power transmitting state, during power driving of the vehicle with the output of the drive power source, and is released to place the automatic transmission in a power disconnecting state, during coasting of the vehicle, the cooperative control apparatus comprising: control initiating condition determining means for determining whether a control initiating condition required to initiate an output increase control for temporarily increasing the output of the drive power source is satisfied or not, depending upon whether an operation to accelerate the vehicle is performed during the coasting of the vehicle while the frictional coupling device is placed in a released state; and output increase control means operable when the control initiating condition determining means determines that the control initiating condition is satisfied, for effecting the output increase control such that the output of the drive power source is larger by a predetermined amount than when the output increase control is not effected.
In the cooperative control apparatus of the present invention constructed as described above, the output of the drive power source is made larger by the predetermined amount by the output increase control means when the control initiating determining means determines that the control initiating condition is satisfied, upon an operation to accelerate the vehicle during coasting of the vehicle with the frictional coupling device placed in the released state, than when the control initiating determining means does not determine that the control initiating condition is satisfied. The output increase control is effective to reduce the time required for the input shaft speed of the automatic transmission to be raised to the synchronizing speed which is a product of the output shaft speed and the speed ratio of the currently established forward drive position of the automatic transmission during the vehicle coasting. Accordingly, the output increase control reduces the accelerating response time from the moment of the vehicle accelerating operation to the moment of engagement of the frictional coupling device to enable the automatic transmission to transmit the vehicle drive power, so that the drivability of the vehicle as felt by the vehicle operator is improved.
In one preferred form of this invention, the frictional coupling device is a one-way clutch which is placed in an engaged state during the power driving of the vehicle, and is placed in the released state when an input shaft speed of the automatic transmission is lower than a synchronizing speed which is a product of an output shaft speed of the automatic transmission and a speed ratio of a currently established forward drive position of the automatic transmission. This one-way clutch is mechanically constructed such that the one-way clutch is automatically engaged when a power is transmitted from the drive power source to drive wheels of the automotive vehicle, and is automatically released when a power is transmitted in the reverse direction. In this form of the invention, the one-way clutch need not be electrically controlled to place this one-way clutch in the released state.
In another preferred form of this invention, the output increase control means increases the output of the drive power source such that an input shaft speed of the automatic transmission in the process of increase of the output of the drive power source does not exceed a synchronizing speed which is a product of an output shaft speed of the automatic transmission and a speed ratio of a currently established forward drive position of the automatic transmission. This form of the invention does not suffer from a rapid reduction in the rate of increase of the input shaft speed of the automatic transmission upon engagement of the frictional coupling device, so that an otherwise possible engaging shock of the frictional coupling device can be suitably avoided.
In a further preferred form of this invention, the output increase control means increases the output of the drive power source such that the output is kept increased while an input shaft speed of the automatic transmission is not higher than a synchronizing speed which is a product of an output shaft speed of the automatic transmission and a speed ratio of a currently established forward drive position of the automatic transmission. In this form of the invention, the input shaft speed of the automatic transmission can be rapidly raised to a value close to the synchronizing speed, whereby the accelerating response of the vehicle can suitably be improved.
In a yet further preferred form of this invention, the control initiating condition determining means includes input shaft speed determining means for determining whether an input shaft speed of the automatic transmission is lower than a synchronizing speed minus a predetermined first value, the synchronizing speed being a product of an output shaft speed of the automatic transmission and a speed ratio of a currently established forward drive position of the automatic transmission. The output increase control means continues to incr
Kondo Masami
Nakamura Yasunari
Bonck Rodney H.
Ho Ha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Toyota Jidosha & Kabushiki Kaisha
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