Interrelated power delivery controls – including engine control – Transmission control – Transmission controlled by engine
Reexamination Certificate
2000-08-21
2002-05-21
Estremsky, Sherry (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Transmission controlled by engine
C477S109000, C477S154000, C477S158000
Reexamination Certificate
active
06390949
ABSTRACT:
This application is based on Japanese Patent Application No. 11-241790 filed Aug. 27, 1999, the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a control apparatus for an automatic transmission of an automotive vehicle, and more particularly to an upshift of the automatic transmission while the vehicle is running in a power-off state.
2. Discussion of the Related Art
There is widely known a power transmitting system for an automotive vehicle, which includes (a) an automatic transmission which is shifted up from a presently established lower-gear position to a higher-gear position having a lower speed ratio than the presently established lower-gear position, by an engaging action of a frictional coupling device by the corresponding hydraulic cylinder, and (b) a hydraulic control device for supplying a pressurized fluid to the hydraulic cylinder to effect the engaging action of the frictional coupling device. JP-A-9-295526 discloses an example of such a power transmitting system including a control apparatus adapted to limit the output of an engine of the vehicle until an upshift of the automatic transmission is completed, where an accelerator pedal is operated in the process of that upshift which was initiated during running of the vehicle with the accelerator pedal placed in the non-operated position. JP-A-9-170654 discloses a power transmitting system including a control apparatus having a pressure regulating device which is adapted to control the pressure of the pressurized fluid to be supplied to the above-indicated hydraulic cylinder such that the fluid pressure is changed at a suitable rate in the process of an upshift of the automatic transmission, or such that the fluid pressure is feedback-controlled so as to change the input speed of the automatic transmission at a suitable rate.
The conventional control apparatus for such power transmitting systems for a motor vehicle is not satisfactory in the control of an upshift of the automatic transmission. For example, the drivability of the vehicle is deteriorated if the engine output is limited until the upshift is completed, where the accelerator pedal is operated in the process of the upshift. If the frictional coupling device is engaged only after the accelerator pedal is subsequently released to its non-operated position, an engine brake may be applied to the vehicle with a result of the vehicle deceleration unexpectedly to the vehicle operator. In the absence of the pressure regulating device indicated above, the moment at which the frictional coupling device has been engaged would tend to differ from the moment at which the input speed of the automatic transmission has reached the synchronizing speed of the higher-gear position. If the generation of the engaging force of the frictional coupling device is initiated before the input speed has reached the synchronizing speed, the vehicle tends to be accelerated unexpectedly to the vehicle operator. If the generation of the engaging force is initiated after the input speed has reached the synchronizing speed, the vehicle tends to be decelerated unexpectedly to the vehicle operator. The latter deceleration is remarkable particularly where the speed of the vehicle drive power source (e.g., engine speed) is raised by an engine braking effect. Even where this engine speed rise is restricted by a one-way clutch which allows the engine speed to be lowered, the vehicle may be unexpectedly decelerated due to a change in the rotating speed of the rotary members of the automatic transmission.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a control apparatus for an automatic transmission of an automotive vehicle, which permits an improved control of an upshift of the automatic transmission during running of the vehicle with the accelerator pedal placed in the non-operated position, more particularly, a control apparatus which, in the absence of the above-indicated pressure regulating device, permits adequate engagement of the frictional coupling device in a suitably timed relationship with the moment at which the input speed of the automatic transmission has reached the synchronizing speed, and more specifically, a control apparatus which permits adequate engagement of the frictional coupling device, so as to prevent deterioration of its durability and minimize unexpected deterioration of the vehicle drivability, when the accelerator pedal is operated in the process of the upshift, and which is effective to prevent unexpected deceleration of the vehicle due to an engine braking effect when the accelerator pedal is subsequently released.
The above object may be achieved according to a first aspect of the present invention, which provides an apparatus for controlling a power transmitting system of an automotive vehicle, the power transmitting system including (a) an automatic transmission which is shifted up from a presently established lower-gear position to a higher-gear position having a lower speed ratio than the lower-gear position, by an engaging action of a frictional coupling device which is operated by a hydraulic cylinder, and (b) a hydraulic control device for supplying a pressurized fluid to the hydraulic cylinder to effect the engaging action of the frictional coupling device, the apparatus comprising: (a) synchronizing time estimating means for estimating a synchronizing time required for an input speed of the automatic transmission to reach a synchronizing speed of the higher-gear position, in the process of an upshift of the automatic transmission during running of the vehicle in a power-off state in which a vehicle drive force is not transmitted to drive wheels of the vehicle through the automatic transmission; (b) a time data memory storing a predetermined stroking time required for a piston of the hydraulic cylinder to reach an engaging stroke end; and (c) timing determining means operable in response to a command to effect said upshift during running of the vehicle in said power-off state, for comparing the synchronizing time with the predetermined stroking time, and thereby determining a point of time at which a supply of the pressurized fluid to the hydraulic cylinder is initiated.
The term “power-off state” of the vehicle is interpreted to mean a state in which the vehicle drive force is not transmitted from a vehicle drive power source such as an engine to the vehicle drive wheels through the automatic transmission. This “power-off state” includes not only a state in which the operator's required output of the drive power source is zero, namely, a state in which the accelerator pedal or other accelerating member for accelerating the vehicle is in the non-operated position, but also a state in which the vehicle drive force is not transmitted to the drive wheels because the operating amount of the accelerating member is smaller with respect to the running speed of the vehicle.
In the vehicle transmission control apparatus according to the first aspect of the present invention constructed as described above, the synchronizing time estimating means estimates the synchronizing time required for the input speed of the automatic transmission to reach the synchronizing speed of the higher-gear position to which the automatic transmission is shifted up, and the timing determining means compares the estimated synchronizing time with the predetermined stroking time stored in the time data memory, and thereby determines the point of time at which the supply of the pressurized fluid to the hydraulic cylinder is initiated. This control arrangement permits the frictional coupling device to be engaged in a suitably timed relationship with the point of time at which the input speed of the automatic transmission has substantially reached the synchronizing speed, irrespective of a variation in the rate of change of the input speed due to a variation in the operating characteristics of the engine. Thus, the present control appara
Kondo Masami
Nakamura Yasunari
Estremsky Sherry
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Toyota Jidosha & Kabushiki Kaisha
LandOfFree
Apparatus for controlling frictional coupling device to... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for controlling frictional coupling device to..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for controlling frictional coupling device to... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2844108