Abstract:
In control apparatus and method for an automatic transmission, a gear shift state of a stepwise variable transmission mechanism is controlled to a target gear shift state by releasing a first engagement section according to a reduction in a capacity of the first engagement section and, simultaneously, by engaging a second engagement section according to an increase in the capacity of the second engagement section, in accordance with a torque inputted to the stepwise variable transmission mechanism and, during an inertia phase, either one of the first and second engagement sections functions as a gear shift state control side engagement section and the capacity of a gear shift state non-control side engagement section which is the other engagement section is increased when determining that it is impossible to make the gear shift state follow up the target gear shift state at the gear shift state control side engagement section.
Abstract:
When a vehicle stops in a travel range, a transmission controller sets a subtransmission mechanism in a second speed interlocking condition in which a torque input into a continuously variable transmission is transmitted in a second gear position and both a frictional engagement element of a first gear position and a frictional engagement element of the second gear position are engaged, and when a predetermined condition is established while the vehicle is stationary, the transmission controller reduces an output shaft torque of the continuously variable transmission.
Abstract:
The transmission controller changes the gear position of the subtransmission mechanism and varies the speed ratio of the variator in an opposite direction to a speed ratio variation direction of the subtransmission mechanism when the actual through speed ratio passes a predetermined mode switch line. When the improvement in the shift response of the continuously variable transmission is determined to be required and the actual through speed ratio passes the mode switch line from a Low side to the High side, the transmission controller increases a shift speed of the subtransmission mechanism compared with a normal coordinated shift.
Abstract:
The transmission controller performs a non-coordinated shift, in which the gear position of the subtransmission mechanism is modified from the second gear position to the first gear position at a higher speed than when the gear position of the subtransmission mechanism is modified by a coordinated shift while permitting a deviation between the through speed ratio and the target through speed ratio, instead of the coordinated shift when it is determined that the second speed kick down shift is to be performed.
Abstract:
A continuously variable transmission includes a variator capable of varying a speed ratio continuously, and a subtransmission mechanism provided in series with the variator. When an actual through speed ratio passes a predetermined mode switch speed ratio, a transmission controller performs a coordinated shift in which a gear position of the subtransmission mechanism is changed and a speed ratio of the variator is varied in an opposite direction to a speed ratio variation direction of the subtransmission mechanism. When the rapid deceleration is determined to be underway, the transmission controller decreases a speed ratio variation amount of the variator in the direction of a High side accompanied by a downshift of the subtransmission mechanism compared with the coordinated shift.
Abstract:
A transmission control unit reduces a hydraulic pressure of a release-side frictional engagement element which is to be released of a sub-transmission mechanism and reduces this reduction amount as an input torque to the sub-transmission mechanism increases at the time of starting a shift when a manual mode is selected, the input torque is positive and the sub-transmission mechanism is to be shifted down.
Abstract:
The shift control unit shifts the sub-transmission mechanism while changing the speed ratio of the variator in response to a change in the speed ratio of the sub-transmission mechanism so that the through speed ratio does not change after the through speed ratio is caused to reach the final through speed ratio by changing only the speed ratio of the variator if the speed ratio corresponding to the shift instruction from the driver is between a first speed ratio at which the sub-transmission mechanism is in the second gear position at the high speed side and the speed ratio of the variator is lowest and a second speed ratio at which the sub-transmission mechanism is in the first gear position at the low speed side and the speed ratio of the variator is highest when the manual mode is selected.
Abstract:
A subtransmission mechanism 30 comprises a Ravigneaux planetary gear mechanism 31, a Low brake 32 and a High clutch 33, shifts between a first speed gear position in which the Low brake 32 is engaged whereas the High clutch 33 is disengaged and a second speed gear position in which the Low brake 32 is disengaged and the High clutch 33 is engaged. A minute slip is caused at the Low brake 32 and then terminated by engaging the High clutch 33. A value representing the engaging state variation such as an engaging time period and/or an engaging speed of the High clutch 33 is learned and the pressure of oil supplied during the engaging operation of the High clutch 33 is corrected based upon the learned value, thereby assuring a smooth shift operation by compensating for any inconsistency in the torque transmission characteristics of the High clutch 33.
Abstract:
A control device for a vehicle continuously variable transmission 4 comprises a shift control means for controlling either of or both the speed ratio at the continuously variable transmission mechanism 20 and the gear position at the subtransmission mechanism 30 so as to adjust an overall speed ratio to a final speed ratio and a torque capacity control means for controlling the torque capacity at a disengagement-side frictional engagement element in the subtransmission mechanism 30 so as to sustain a torque capacity value substantially equal to zero in an inertia phase occurring during a process of adjusting the gear position at the subtransmission mechanism 30 from the first gear position to the second gear position when a negative torque is input to the vehicle continuously variable transmission 4.
Abstract:
A continuously variable transmission 4 for a vehicle includes a variator 20 that modifies a speed ratio continuously and a subtransmission mechanism 30 that is connected in series to the variator 20 and applies a first speed and a second speed, which is higher than the first speed, selectively. When the vehicle is running under a low load/high speed upshift condition having a lower load or a higher speed than a normal upshift condition, the subtransmission mechanism 30 is upshifted from the first speed to the second speed at a lower vehicle speed than under the normal upshift condition, and as a result, both rotation variation in an internal combustion engine 1 accompanying upshifting of the subtransmission mechanism 30 and an increase in a fuel consumption amount of the internal combustion engine 1 due to the shift operation in the continuously variable transmission 4 are suppressed.