Abstract:
A shift control system for an automatic is designed to prevent engine racing and clutch tie-up during a clutch-to-clutch shift (clutch switching shift) involving engagement/disengagement of first and second frictional engagement elements. The shift control system includes an engagement force controller for independently controlling both of the frictional engagement elements. A gear ratio calculator continuously calculates a gear ratio r of the transmission and a shift characteristic value calculator calculates a shift characteristic value .alpha. based on changes in the gear ratio between the start of the shift and completion of the shift. A control value calculator calculates a control value .beta., based on the shift characteristic value .alpha. calculated by the shift characteristic value calculator and a shift characteristic value .alpha.I on an ideal gear ratio curve. The control value .beta. is calculated so that the shift characteristic value .alpha. coincides with the shift characteristic value .alpha.I on the ideal gear ratio curve.
Abstract:
A control system for a multiple ratio transmission including a hydrokinetic torque converter with a pressure actuated friction bypass clutch, pressure actuated clutches and brakes controlling ratio changes in forward drive and for effecting reverse drive, a solenoid operated pressure control that develops an optimum clutch and brake pressure for smooth engagement and for increased torque capacity during start-up, and separate solenoid regulator valves for ratio shift valve control and for bypass clutch pressure control.
Abstract:
The present invention is directed to a device and a method for controlling a shift position of a vehicle in response to a road condition when the vehicle is running on a steeply sloped road or a sharply curved road. The device includes a slope/curve sensor, a steering angle sensor, a throttle valve sensor, a vehicle speed sensor, and a shift controller. A solenoid valve controls a hydraulic pressure and the resulting shift position in response to a control signal applied from the shift controller.
Abstract:
A lock-up clutch by way of which input/output shafts of a torque converter are operatively connected to each other is connected to an electronic type pressure control valve. During speed changing in a transmission, the problem of interruption of torque transmission can be solved by turning off the lock-up clutch at the time when filling of one of the speed changing clutches to be next brought into an operatively engaged state with hydraulic oil is completed. Hydraulic pressure (P.sub.t) in the torque converter is exerted on the back 100 pressure portion of a piston of the lock-up clutch while hydraulic pressure (P.sub.t) in the torque converter is exerted on the proportional solenoid side of the pressure control valve, making it possible to reduce the initial hydraulic pressure. During speed changing, the lock-up clutch is not fully released from the engaged state but maintains its operative state at low pressure, causing shock from shifting the lock-up state to be reduced. When hydraulic pressure is gradually increased, the extent of opening the throttle, weight of the vehicle and the current gear ratio are derived so as to vary the rate of gradual increase of hydraulic pressure depending 100 on values of these parameters.
Abstract:
An electromagnetically operated proportional valve, in particular a pressure regulating valve for automatic transmission of motor vehicles has a magnet housing, a magnet coil and stationary flux guiding elements received in the magnet housing, a magnet armature, a valve member with which the magnet armature cooperates, stationary structural elements forming at least one auxiliary air gap and a working air gap in a magnetic circuit, the valve member cooperating with the stationary structural elements through the at least one auxiliary air gap and the at least one working air gap, at least one of the structural elements cooperating in the working air gap being at least partially provided on at least one surface facing a corresponding another structural element with at least one nonmagnetic coating.
Abstract:
A hydraulic control for an automatic transmission is composed of a gear shift mechanism having first and second frictional engagement elements, a hydraulic control unit for the engagement elements, and an electronic control unit for the hydraulic control unit. The first element is engaged to achieve a first speed stage and the second element is engaged to achieve a second speed stage faster than and closest to the first speed stage. The hydraulic control unit has a first directional control valve for switching the feeding and discharge of hydraulic pressure between the first and second engagement elements, responsive to a first solenoid signal from the electronic control unit. A second directional control valve is adapted to be switched by a second solenoid signal from the electronic control unit to achieve a third speed stage yet faster than the second speed stage. The first engagement element has a discharge line connected to a drain line via the second directional control valve. The electronic control unit has a detector for determination of tie-up of either or both of the engagement elements, whereby upon detection of tie-up by the detector, the second solenoid signal is output to the second directional control valve.
Abstract:
An electromagnetic valve, in particular switching or pressure regulating valve for an automatic transmission of motor vehicles has a magnet housing, a magnet coil with a coil body received in the magnet housing, a valve member, a magnet armature through which the magnet coil cooperates with the valve member, a valve closing part connected with the magnet housing, electrical contacts for controlling the magnet coils and arranged outside of the magnet housing, and conductors extending through the magnet housing and connecting the electrical contacts with the magnet coil. The magnet housing is composed of at least two magnet casing elements, including a first magnet casing element and also a second magnet casing element which at least partially overlaps the first magnet casing element, at least one of the magnet casing elements having a recess through which the conductors extend to the electrical contacts.
Abstract:
An R-N-D control valve of a hydraulic control system is disclosed which ensures the prevention of shock that may occur at the time of an "N-R" and an "N-D" manual shift, by unifying a shift control pressure with one valve in the case of an "N-R" shift and an "N-D" shift and first-second speed shift. The present invention discloses that a line pressure generated from a manual valve is changed to a control pressure controlled by the proportional control of a linear valve, and transmitted to each clutch and brake according to the movement position of a spool of a valve by the line pressure.
Abstract:
An apparatus and method are adapted for detecting an end-of-fill condition of an actuator having a varying control volume is provided. The end-of-fill condition corresponds to the varying control volume being pressurized to a predetermined end-of-fill pressure. The apparatus comprises a solenoid having a coil and an armature. The armature is movable relative to the coil in response to energization of the coil. A valve delivers a flow of fluid to the actuator. The fluid flow having a rate responsive to the movement of the armature. The apparatus and method controllably energizes the coil with a control current. The apparatus and method detects a flyback current in the coil, detects a change in the level of noise in said flyback current, and responsively producing an end-of-fill signal in response to the change being greater than a predetermined threshold.
Abstract:
The disclosed hydraulic control system for an automatic transmission has a main pressure valve to control main pressure produce by a pump, a manually operated slide valve to select a transmission condition, and electromagnetically operable valve arrangements receiving main pressure from the manual slide valve and by which the various main pressure levels are adjustable at corresponding transmission shift elements. At least one of the electromagnetic valve arrangements has a slide valve and an electromagnetic valve capable of being influenced by a control unit and at least one face of the slide valve is capable of being acted on by pressure.