Abstract: A shift control method for executing a shift-up control from an off-going range to an on-coming range comprises an off-going-range releasing stage, an off-going-range controlling stage, and an on-coming-range invalid-stroke-clearing stage. In the off-going-range releasing stage, a pressure command signal is generated to quickly lower the engagement-actuation pressure of the off-going engaging element. In the off-going-range controlling stage, a pressure command signal is generated to control the engagement-actuation pressure of the off-going engaging element in such a way that the off-going engaging element is kept slipping within a predetermined range of input/output rotational speed ratio (=output rotational speed/input rotational speed).

Abstract: An engagement-actuation control for a frictionally engaging element to establish a driving range in response to a shift command to shift from a neutral range to the driving range comprises a plurality of control stages including an invalid-stroke-clearing control. This invalid-stroke-clearing control is finished when invalid-stroke clearing is judged complete on the basis that the absolute value of the rate of rotational change of a turbine shaft is equal to or greater than a predetermined rate and that the difference between the rotational speed of an engine and the rotational speed of the turbine shaft is equal to or greater than a predetermined value.

Abstract: In a sealing device, a crank-shaped oil channel is defined in an abutment of a sealing ring for sealing between a shaft member and a housing which surrounds the shaft member and is rotatable relative the shaft member. The crank-shaped oil channel is comprised of a first oil channel portion and a second oil channel portion which extend axially, and a third oil channel portion which connects the first and second oil channel portions to each other. If the sealing ring is thermally expanded circumferentially due to a change in temperature, the sectional area of the flow path in each of the first and second oil channel portions is varied, but the sectional area of the flow path in the third oil channel portion is not substantially varied. Therefore, it is possible to leak a given amount of an oil from one side of the sealing ring through the crank-shaped oil channel to the other side, thereby preventing the wearing of the shaft member caused by foreign matter, such as an iron powder, contained in the oil.

Abstract: A shift control apparatus for an automatic transmission for a vehicle wherein D-N-D in-gear shifts are carried out quickly without any shift shock. Engagement-actuation control for a frictionally engaging element to establish a D range when a shift is made from a N range to the D range comprises a plurality of control stages, for example, an invalid-stroke clearing stage, an intermediate-pressure retaining stage, a feedback stage, etc. When the shift to the D range is made following a shift from the D range to the N range, a shift control apparatus detects the engagement condition of the the frictionally engaging element for establishing the D range, selects one of the control stages in correspondence with the engagement condition, and initiates the engagement-actuation control for the frictionally engaging element from the control stage selected.

Abstract: A continuously variable transmission on a motor vehicle is controlled to control a speed reduction ratio using, as a control value, a rate of change di/dt of the speed reduction ratio that is determined using a reserve horsepower of an engine on the motor vehicle, an engine rotational speed Ne, a vehicle speed V of the motor vehicle, a present acceleration Ga of the motor vehicle, and a target acceleration Gon. A control process detects whether a rate of change of an indication by a driver of the motor vehicle of an intention to accelerate or decelerate the motor vehicle is greater than a predetermined value or not, whether a target engine rotational speed Neo corresponding to the indication is greater than an actual engine rotational speed Nea or not and whether the target acceleration Gon is greater than the present acceleration Ga on an acceleration side (positive side) or not.

Abstract: A hydraulic servo unit for changing the swash plate angle of a continuously variable transmission to vary its speed reduction ratio comprises a cylinder whose chamber is divided into a rod-side chamber and a head-side chamber by a piston slidably fitted therein. The rod-side chamber is supplied with working oil under predetermined hydraulic pressure through a first hydraulic pressure supply passage. A second hydraulic pressure supply passage is connected to the head-side chamber through a duty-cycle-controlled first solenoid-operated valve, and a drain hydraulic passage is connected to the second hydraulic pressure supply passage through a second duty-cycle-controlled solenoid-operated valve. The first and second solenoid-operated valves are simultaneously actuated with different duty cycles.

Abstract: A control system for controlling the throttle opening of an engine of an automobile has a stepping motor for actuating a throttle valve disposed in an intake passage of the engine to control the throttle opening, an accelerator operation detecting unit for detecting the amount of operation of an accelerator pedal operated on by the driver of the automobile, an engine operating condition detecting unit for detecting an operating condition of the engine, and a controller for controlling the stepping motor based on detected values from the accelerator operation detecting unit and the engine operating condition detecting unit.

Abstract: The solenoid valve 30 is mounted on the mounting member 10 with the inlet port section 31 positioned at the lower end thereof extending out downwardly from the bottom face of the mounting member 10, and this mounting member 10 is mounted on the base member 1 to cover the supplied oil path 2 and the discharged oil path 3 formed in the base member 1. The inlet port section 31 of the solenoid valve 30 extending out from the bottom surface of the mounting member 10 extends into the supplied oil path 2, thus the inlet port 31a and the supplied oil path 2 are communicated to each other. Furthermore, the outlet port 31b of the solenoid valve 30 is communicated to the discharged oil path 3 via the communicating groove 12 formed on the bottom surface of the mounting member 10. Also, the electric connector 21 is mounted on the mounting member 10 and the wiring members 25, 26 and 27 connecting the solenoid 36 of the solenoid valve 30 to this electric connector 21 are buried inside the mounting member 10.

Abstract: A shift control apparatus controls the shifting of a transmission by selecting one power transmitting path at a time from a plurality of paths respectively having different speed reduction ratios. At least one power transmitting path is provided with a one-way clutch and an engine-brake clutch is included in the plurality of paths. The one-way clutch can be locked by the engine-brake clutch. An engine-brake clutch control valve is provided for controlling the engine-brake clutch. Two solenoid valves are provided for controlling the engine brake clutch control valve. When one of the two solenoid valves fails and is inactivated, the other solenoid valve is used to cause the engine-brake clutch control valve to engage the engine-brake clutch.

Abstract: A clutch engaging torque which will be required by a hydraulically operated clutch to be engaged for a gearshift is preset. A hydraulic pressure required to obtain the clutch engaging torque while the hydraulically operated clutch is at rest is calculated. Then, a corrective action is effected by, for example, subtracting from the hydraulic pressure a centrifugal hydraulic pressure which will be developed in the hydraulically operated clutch by the rotation thereof in the gearshift, thus determining a hydraulic pressure to operate the hydraulically operated clutch.

Abstract: If the accelerator pedal condition is a power-on condition and the gearshift type is an upshift, or the accelerator pedal condition is a power-off condition and the gearshift type is a downshift, then a torque for engaging the next-gear-position gearshift means is established based on the engine torque to be transmitted from the engine to the next-gear-position gearshift means, and an inertia torque required to make the rotational speed of the input member of the next-gear-position gearshift means vary as desired with respect to the gearshift. If the accelerator pedal condition is a power-on condition and the gearshift type is a downshift, or the accelerator pedal condition is a power-off condition and the gearshift is an upshift, then the ratio between the rotational speeds of the input and output members of the next-gear-position gearshift means is detected.

Abstract: Engine racing is determined during shift in an automatic transmission having clutches associated with respective gear positions, by, after a shift command is issued to effect a shift in a power-on mode, detecting the input and output rotational speed ratios of previous-gear-position and next-gear-position clutches of the transmission, and determining that engine racing has occurred if the input and output rotational speed ratio of one of the clutches which is normally greater than 1.0 during a gear shift remains below a threshold value slightly smaller than 1.0 for a predetermined period of time.

Abstract: When a gearshift command for a power-on/downshift or power-off/upshift mode is issued, the magnitude of a change in the engine rotational speed due to the gearshift is calculated from the vehicle speed or the engine rotational speed when the gearshift starts to be effected and the gear ratio of a gear position to be reached by the gearshift. If the magnitude of the engine speed change is large, then a hydraulic control pressure is lowered for a certain period of time to advance the timing of operating of a hydraulic pressure release valve to quickly disengage a previous-gear-position clutch. If the magnitude of the engine speed change is small, then the control pressure is increased to delay the timing of operation of the hydraulic pressure release valve to allow the previous-gear-position clutch to be disengaged after a next-gear-position clutch starts to be engaged.