Jatco Corporation

Nissan Motor Company Limited

Hiromichi Akebono

Hideharu Yamamoto

Hisashi Saito

Kota Miura

Osamu Sato

Hiroki Matsui

Akio Nonomura

Seiichirou Takahashi

Isamu Ohtake

Shohei Imaji

Katsuyuki Hara

A belt-type continuously variable transmission includes a primary pulley, a secondary pulley, and a belt wound around the primary pulley and the secondary pulley. A controller performs a process, when performing a low speed position return shift to shift a transmission ratio toward a lowermost speed position while a vehicle is decelerating. The process includes: calculating a primary pressure actual lower limit, at which the belt actually starts to slip, based on the transmission ratio and a deceleration of the vehicle; setting a lower limit of a setpoint of the primary pressure to the primary pressure actual lower limit; setting the primary pressure actual lower limit higher with a locking tendency of a vehicle wheel detected than that without the locking tendency detected; and setting the primary pressure actual lower limit with the locking tendency detected to increase as the transmission ratio varies toward the lowermost speed position.

Belt-type continuously variable transmission

A transmission controller determines that a select operation has been performed from a reverse range to a drive range if a time during which a range other than the drive range has been selected is longer than a predetermined time threshold value and an input rotation speed of a transmission is lower than a predetermined rotation speed threshold value and determines that the select operation has been performed from a parking range or a neutral range to the drive range if the time during which the range other than the drive range has been selected is shorter than the time threshold value or the input rotation speed is higher than the rotation speed threshold value when the select operation has been performed from the range other than the drive range to the drive range during vehicle stop.

Automatic transmission and select operation determination method for automatic transmission

A device for controlling an automatic transmission includes: a position detection means for detecting a shift position; a vehicle speed detection means for detecting a vehicle speed; a rotation frequency detection means for detecting an input rotation frequency of the automatic transmission; and a control means for, when the shift position has been switched from a parking position or a neutral position to a driving position, making a determination about switching from stopped-state control to running-state control based on the vehicle speed after a physical amount indicating a state of the automatic transmission becomes equal to or larger than a predetermined value, the stopped-state control being control for a hydraulic pressure supplied to engaging elements based on the input rotation frequency of the automatic transmission, and the running-state control being control for the hydraulic pressure supplied to the engaging elements without using the input rotation frequency of the automatic transmission.

Device for controlling automatic transmission and method for controlling same

A transmission controller increases an indicated hydraulic pressure to a starting frictional engagement element to a normal hydraulic pressure, causes a hydraulic piston to stroke and executes a learning control of the indicated hydraulic pressure so that a time until the starting frictional engagement element starts generating a transmission capacity after the range is switched from the neutral range to the drive range becomes a target time when a range is switched from a neutral range to a drive range. The transmission controller further detects a driver's starting intention and increases the indicated hydraulic pressure to the starting frictional engagement element to a starting time hydraulic pressure higher than the normal hydraulic pressure and prohibits the learning control if the starting intention is detected before the starting frictional engagement element starts generating the transmission capacity.

Automatic transmission and starting time control method

A control system includes a drive source including an engine and a motor. A clutch is provided between the drive source and a driving wheel, wherein the clutch is engaged when a drive range is selected. The system performs, by a speed control of the motor, a control for keeping an input speed of the clutch at a target speed that is equal to the input speed at start of an engagement control of the clutch. The system judges that the clutch has started to be engaged, in response to a condition that a parameter has exceeded a predetermined threshold value when in a start region of the engagement control of the clutch, wherein the parameter changes along with a rotational fluctuation of the drive source. The system starts the judgment after awaiting satisfaction of a predetermined condition after the start of the engagement control of the clutch.

Device for controlling hybrid vehicle

A control device of an FR hybrid vehicle is provided with: a drive source that contains at least an engine (Eng); and a second brake (B) that is fastened when a D range is selected. In the range of starting of fastening control of the second brake (B), when the parameters (rate of input rotational frequency change and amount of motor torque change) that change along with the rotational fluctuation of the engine (Eng) become at least a predetermined threshold, it is judged that the second brake (B) has started fastening. When in a state wherein the rotational fluctuations of the engine (Eng) can be determined to be large, the absolute value of the predetermined threshold is set to a value that is larger than when in a state wherein the rotational fluctuations of the engine (Eng) can be determined to be small.

Vehicle control device

In control apparatus and method for a vehicle, the vehicle including a traveling mode (a WSC traveling mode) in which a slip control is performed for a clutch (second clutch CL) and a revolution speed control is performed for the driving source such that a revolution speed at a driving source side of the clutch becomes higher than that at a driving wheel side of the clutch by a predetermined revolution speed, an actual torque of a driving source of the vehicle is detected, a command hydraulic pressure is reduced from an initial command hydraulic pressure and a post-correction command hydraulic pressure is set on a basis of the command hydraulic pressure when a variation in the actual torque of the driving source along with the reduction of the command hydraulic pressure is determined to end, when a vehicle stopped state is determined to occur during the traveling mode.

Control apparatus for vehicle and control method therefor

A hybrid electric vehicle has a first mode in which slippage of a clutch between an electric motor and a driving wheel is allowed and controlled by rotational speed control of the electric motor and a second mode in which the slippage of the clutch is allowed and controlled by rotational speed control of an engine. When the vehicle is stationary in the first mode, a controller reduces a control setpoint of hydraulic pressure of the clutch from an initial point. The controller identifies a reference point of the control setpoint with which actual output torque of the electric motor becomes unchanged with respect to the reduction of the control setpoint. Then, the controller increases the control setpoint from the reference point at a higher gradient and then a lower gradient, and then sets the control setpoint to a corrected point below the initial point and above the reference point.

Vehicle control apparatus and vehicle control method

A hybrid electric vehicle has a first mode in which slippage of a clutch between an electric motor and a driving wheel is allowed and controlled by rotational speed control of the electric motor and a second mode in which the slippage of the clutch is allowed and controlled by rotational speed control of an engine. When the vehicle is stationary in the first mode, a controller reduces a control setpoint of hydraulic pressure of the clutch from an initial point. The controller identifies a reference point of the control setpoint with which actual output torque of the electric motor is substantially constant with respect to the reduction of the control setpoint. Then, the controller increases the control setpoint to a precharge point, and reduces the control setpoint to a corrected point that is lower than or substantially equal to the initial point and higher than the reference point.

An automatic transmission includes: a frictional engagement element arranged to be switched from an engagement state to a disengagement state at a switching from a running range to a neutral range, and including: frictional plates; a first piston arranged to push the frictional plates; a second piston arranged to push the frictional plates; a first hydraulic chamber arranged to receive a hydraulic fluid for pushing the first piston; and a second hydraulic chamber arranged to receive a hydraulic fluid for pushing the second piston; a first discharge speed switching section arranged to switch only a discharge speed of the hydraulic fluid of the first hydraulic chamber; and a control unit configured to increase the discharge speed of the hydraulic fluid of the first hydraulic chamber during a predetermined time period by the first discharge speed switching section at the switching from the running range to the neutral range.

Control apparatus for automatic transmission

There is provided a hydraulic control device for controlling a hydraulic pressure supplied to a vehicle start-up engagement element in an automatic transmission when a shift lever is moved from a non-drive range position to a drive range position. The hydraulic control device has a target pressure setting section that sets, based on an input torque of the automatic transmission, a target value of hydraulic pressure supplied to the vehicle start-up engagement element at the completion of engagement of the vehicle start-up engagement element and corrects the target value periodically based on the transmission input torque until the completion of engagement of the vehicle start-up engagement element and a hydraulic pressure control section that controls the hydraulic pressure in such a manner that the hydraulic pressure supplied to the vehicle start-up engagement element reaches the corrected target value at the completion of engagement of the vehicle start-up engagement element.

Hydraulic control device and method for automatic transmission

An automatic transmission control apparatus is provided with a brake switch, a brake fluid pressure detecting section, a range position detecting section, a neutral control section and a prohibiting section. The brake switch is configured to output an on-signal when a brake pedal is depressed and otherwise output an off-signal. The brake fluid pressure detecting section is configured to detect a brake fluid pressure corresponding to a brake pedal depression force. The range position detecting section is configured to detect if a traveling range of an automatic transmission is selected. The neutral control section is configured to start a neutral control that puts the automatic transmission into a neutral state when the brake fluid pressure detected by the brake fluid detecting section exceeds a start threshold value while the range position detecting section detects that the traveling range is selected, and to end the neutral control when the brake fluid pressure falls below an end threshold value while the neutral control is being executed, with the start and end threshold values being set to values that are higher than the brake fluid pressure occurring when the brake switch starts outputting the on-signal. The prohibiting section is configured to prohibit the neutral control from being subsequently started again, after the neutral control has been started by the neutral control section, regardless of the brake fluid pressure detected by the brake fluid pressure detecting section until the brake switch outputs the off-signal.

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Machida, Japan

Hiromichi Akebono