摘要:
A subpump assists a main pump for feeding hydraulic oil into a vehicle transmission system so as to control the distribution of the drive force transmitted to front and rear wheels. A motor for driving the subpump is started with a predetermined timing and energized for a predetermined drive time, so that the subpump circulates hydraulic oil with air which is mixed into the hydraulic oil by a chain that is turned in an oil tank, from a strainer chamber for the subpump, to prevent accumulation of air in the oil tank.
摘要:
A lock-up type automatic transmission system includes a torque converter having a lock-up control valve and a lock-up solenoid for controlling the lock-up control valve. In the lock-up state, the lock-up control valve supplies a torque converter operating pressure to an apply chamber of the torque converter and it connects a release chamber of the torque converter to a drain circuit. In the converter state, the lock-up control valve supplies the operating pressure to the release chamber and connects the apply chamber to the drain circuit. In the lock-up state, when the apply pressure to the apply chamber reaches or exceeds a predetermined level, the lock-up control valve operates as a by-pass valve and directs excess hydraulic fluid, which is directed to the apply chamber, to the drain circuit or an oil cooler interposed in the drain circuit.
摘要:
A hydraulic circuit for a lock-up device includes a valve arranged in an oil path for supplying hydraulic pressure to a hydraulic power transmission. The valve regulates flows of hydraulic oil discharged toward a cooling circuit or a lubricating circuit, corresponding to a signal in relation to an engine torque. Therefore, corresponding to the engine torque, it is possible to maintain the hydraulic pressure for the hydraulic power transmission, which is necessary for lock-up condition of the lock-up device.
摘要:
A shift control system in an automatic transmission controls a shifting which necessitates redeployment of friction elements so that one friction element is engaged while the other friction element is released. In reply to a shift command, the shift control system starts to control one of the engagement pressure of the friction element to be engaged or the disengagement pressure of the friction element to be disengaged. Next, the shift control system starts to control the other one of the engagement pressure or the disengagement pressure at a moment at which a preset time has elapsed from the start of the shift command. The preset time is corrected so as to decrease a physical quantity indicative of discord of the timing between the engagement and the disengagement. Accordingly, the preset time firmly takes a proper time so as to carry out the deployment of both friction elements at a synchronized point due to such a learning control. This enables the shift feeling to always be kept good.
摘要:
A shift control system comprises duty solenoid valves by which engagement pressure of one friction element to be released and that one of the other friction element to be engaged can be controlled individually.
摘要:
A hydraulic control device for an automatic transmission comprises a shift valve and a control valve which are coaxially aligned in a valve chamber. The shift and control valves of a spool type control connecting states of first and second clutches of the automatic transmission, respectively. The shift and control valves are separated by a retainer having a through-hole through which a part of the control valve pushes the control valve so as to change the operating state of the control valve. The shift valve takes one of a first state where a hydraulic chamber of a first clutch is communicated with a drain port and a second state where the first clutch hydraulic chamber is communicated with a line pressure. In the first state of the shift valve, the control valve is set to control the line pressure and communicate a hydraulic chamber of a second clutch and the controlled line pressure. In the second state of the shift valve, the control valve is pushed by the shift valve and is set to communicate the second clutch hydraulic chamber and a drain port.
摘要:
In order to attenuate the occurrence of a double select shock which results from the use a first one-way clutch which is used in a first gear train and is involved in the generation of lowest speed thereof, and a second one-way clutch in an auxiliary gear train which is arranged between the main gear train and the final drive, the vehicle speed is sensed and while it is below a predetermined low value, a friction element which is arranged in parallel with the second one-way clutch is engaged. Above the predetermined low value the friction element engagement is maintained in the event that an engine braking demand signal is present.
摘要:
A predetermined control on an engine, i.e., a fuel-cut operation, is executed after an accelerator has been released under predetermined conditions when vehicle speed is higher than a fuel-cut vehicle speed value and engine speed is higher than or equal to a fuel-cut engine speed value. In an automatic transmission drivingly connected to the engine via a torque converter, a gear shift is initiated after the accelerator has been released. During a shift of the same kind, there occurs a variability in shift shock between the cases with and without the execution of the fuel-cut operation. In order to reduce this variability, the execution of the fuel-cut operation is inhibited until completion of the shift after the accelerator has been released under the predetermined conditions.
摘要:
When a transmission requires an upshift with the prime mover operating under minimal load, the rotational speed of the output shaft of a planetary gear set in which a one-way clutch is subject to load when torque is transmitted from the prime mover to the vehicle wheels via the transmission, is monitored and the upshift inhibited until such time as the rotational speed conditions are such as to indicate that the output shaft is rotating faster than it would be driven by the prime mover.
摘要:
A unified control device for engine and automatic transmission of an automotive vehicles serves to alleviate a racing select shock which occurs upon engagement of a driving clutch in the transmission when selecting a running range of the transmission to start the vehicle with an accelerator pedal depressed. The control device achieves a reduction control during changeover of the transmission into a running range from a racing state, to reduce at least one parameter representing the output power to be transmitted from the engine to driving wheels via the transmission, such as engine speed, engine output and/or transfer torque capacity of the clutch, etc. The reduction control is stopped as soon as the completion of engagement of the driving clutch has been detected, to allow the vehicle to be started without engine stalling.