Abstract: Herein disclosed is a hydraulic servomechanism control system in an automatic transmission, for modulating the oil pressure of any hydraulic servomechanism to engage or release frictional engagement devices. The control system comprises: two pressure modulating mechanisms for modulating the oil pressure of said hydraulic servomechanisms; and a shutoff mechanism for shutting off, when one of said pressure modulating mechanisms is caused to communicate with said hydraulic servomechanism, the communication between the other pressure modulating mechanism and said hydraulic servomechanism.

Abstract: In an automobile equipped with an engine, an automatic transmission including hydraulically actuated friction engaging means for shifting stages of the transmission, and an oil pump driven by the engine to provide a pressurized oil for actuating the friction engaging means, the capacity of the oil pump is so minimized as to be only enough for shifting the stages of the transmission, if the idle speed of the engine is temporally increased, when the temperature of oil of the transmission is above a threshold value.

Abstract: A shift control system for an automatic transmission including a first transmission assembly for changing gear ratios in accordance with the release or engagement of a first frictional engagement system and a second transmission assembly connected in series to the first transmission assembly for changing gear ratios in accordance with the engagement or release of a second frictional engagement system. It includes a decision system for deciding whether or not the automatic transmission should execute the gear changes and a time lag controller for making the time lag for the second frictional engagement system to be engaged shorter than the time lag for the second frictional engagement system to be engaged for another gear change when the automatic transmission is to execute the gear changes.

Abstract: A control system in an automatic transmission for controlling the change-over of the three speed change patterns which are a speed change pattern having a cross gear ratio on a low speed side, a speed change pattern having a cross gear ratio on a high speed side and a speed change pattern having a normal gear ratio. According to this controlling system, when one of the three speed change pattern is selected based one a throttle opening and a vehicle speed, and when it is judged that the gear shift from a speed range in the present speed change pattern to a speed range in the selected speed change pattern falls under on of prohibited conditions, e.g., requiring engagement and/or disengagement of three or more frictional engaging elements for the gear shift, the gear shift is performed using a temporary speed change pattern (including the present speed change pattern) including a speed range not falling under the prohibited conditions.

Abstract: A linear solenoid valve apparatus for discharging foreign matter collected at the exhaust port by engaging the electromagnet of the linear solenoid valve. The apparatus includes a linear solenoid valve having a valve sleeve, a spool, a spring, and an electromagnet, and a modulator valve including an exhaust port in which foreign matter is collected. The electromagnet is energized by foreign matter discharging control, responsive to detection of lack of need for output pressure from the solenoid valve, so that the foreign matter is discharged from the exhaust port.

Abstract: A lock-up apparatus in a torque converter includes a first oil chamber (25) and a second oil chamber (26) delimited by a lock-up piston (21), a first oil line system (A) communicating with the first oil chamber (25), and a second oil line system (B) communicating with the second oil chamber (26). An orifice (36) and an oil line (37) for directly communicating the first oil line system (A) and the second oil chamber (26) are provided in an output shaft (20) and a turbine hub (19), respectively. Accordingly, the first oil chamber (25) and the second oil chamber (26) are not directly communicated. As a result, not only is shock produced at release from the locked up state mitigated by the orifice (36) and oil line (37), but it is also possible to reliably prevent a decline in transmission torque capacity in the lock-up ON state.

Abstract: A shift control system for use in an automatic transmission which is connected to an engine and capable of changing the output torque of the engine during a shift. The automatic transmission includes first and second transmission assemblies connected in series to each other and each having a plurality of rotary components.

Abstract: A shift control system for an automatic transmission includes a first transmission assembly for changing gear ratios in accordance with the release or engagement of a first frictional engagement system and a second transmission assembly connected in series to the first transmission assembly for changing gear ratios in accordance with the engagement or release of a second frictional engagement system.

Abstract: A shift control system for an automatic transmission comprises: a first transmission assembly and a second transmission assembly connected in series to each other and individually having frictional engagement elements to be engaged, if subjected to oil pressures, and accumulators for regulating the oil pressures to be applied to the frictional engagement elements, so as to set any one of gear stages by applying the frictional engagement elements of one of the transmission assemblies to shift up the one transmission assembly and by releasing the frictional engagement elements of the other transmission assembly to shift down the other transmission assembly.

Abstract: In a downshifting of an automatic transmission with an engine being generally maintained in a substantial power generating condition in a vehicle, the output torque of the engine is decreased by an amount prior to a substantial establishment of a torque transmitting route in the automatic transmission for a shifted down speed stage, and then the output torque of the automatic transmission is repetitively monitored at a certain small scanning cycle after the start of establishing the torque transmitting route in the automatic transmission for the shifted down speed stage, while the monitored output torque of the automatic transmission is repetitively compared with a target value determined therefor at the scanning cycle, thereby progressively recovering the output torque of the engine at the scanning cycle by an amount corresponding to the repetitive comparison of the monitored output torque of the automatic transmission with the target value determined therefor so as to cancel a difference in each comparison.

Abstract: A hydraulic breather for a valve body in an automatic transmission, in which is disposed hydraulic equipment, for example, linear solenoid valves. The breather separates oil in the oil pan from the oil in the hydraulilc equipment when the automatic transmission is at work while allowing clean oil from the oil pan to enter the hydraulic equipment when the automatic transmission is at rest. The breating hole is provided in the form of an oil passage extending from hydraulic equipment within the valve body and includes an open-end section disposed in an upper part of the valve body. The open-end is located at a point higher than the working oil level in the automatic transmission. When the automatic transmission is at work, oil in the oil pan is used to lubricate, so the oil level is at its lowest level and the open-end section is above that oil level and thereby connects with air space in the valve body.

Abstract: In a speed stage shifting of an automatic transmission in a vehicle by engagement of a hydraulically operated friction engaging means through supply of a hydraulic fluid to the friction engaging means via a passage means including an accumulator operative with support by a back pressure, the back pressure is first maintained at an incipient pressure level, and is increased from the incipient pressure level toward a regular pressure level upon the lapse of a delay time from the detection of a transition phase when the transition phase starts before the lapse of a guard time or upon the lapse of the guard time when the guard time lapses before the start of the transition phase.

Abstract: A shift control system for an automatic transmission including first and second transmission assemblies, which are arranged in tandem to have their shifts controlled individually, and capable of selecting at least two gear stage trains, each being composed of a plurality of gear stages set by combining the first and second transmission assemblies, which are decided under a predetermined condition.

Abstract: A shift control system and method for an automatic transmission connected to an engine having engine intake controller includes a detector for detecting the start of an inertia phase at the time of a shift. An intake changing device outputs a first command signal for throttling the opening of the intake controller to such an extent that the engine torque is unvaried for a time period from the output of a command signal for the shift to the start of the inertia phase, and a second command signal for further throttling the opening of the intake controlling, simultaneously as the start of the inertia phase is detected, to drop the engine torque.

Abstract: A primary regulator valve has a cutback port which regulates a line pressure to increase, at the first speed of D range, a throttle pressure is applied to the cutback port through a cutback valve. The primary regulator valve sets the line pressure from a line pressure port higher. The cutback valve has a spool which is compressed in one direction. A first control chamber which is connected to a hydraulic servo (for example, a second brake hydraulic servo) which hydraulic pressure is applied at more than the second speed is formed against the pressing direction, a second control chamber which is connected to a hydraulic servo (for example, a second-coast brake hydraulic servo) to limit a coasting condition of the second speed is so formed as to follow the above pressing direction. At the second speed of second range, the cutback valve, as the first speed of D range, the throttle pressure is applied to the cutback port.

Abstract: A reverse-engaging condition is prevented by a reverse inhibit valve operated by the solenoid valve even if a shift lever is operated to a reverse range at forward running. A solenoid valve controlling a 1-2 shift valve is "OFF" when controlling a manual valve to a reverse range under 7 km/h of a vehical speed. The reverse inhibit valve is at a right-half position. Therefore, the hydraulic pressure from the reverse range port of the manual valve runs through oil passages and supplied to the hydraulic servos. At forward running over 7 km/h the solenoid valve is switched "ON", the reverse inhibit valve is switched to a left-half position and oil passages are isolated. When the solenoid valve is switched at forward running, a hydraulic pressure from a R range port of the manual valve does not operate on a difference of cross sectional areas of lands of the reverse inhibit valve, so that the reverse inhibit valve is kept at the right-half position together with a pressing force of a spring therein.

Abstract: A power control system for use with an engine which is connected through a torque converter to a transmission includes a speed ratio calculating device for determining the speed ratio of the torque converter, a torque ratio calculating device for determining the torque ratio of the torque converter from the speed ratio, a capacity factor calculating device for determining the capacity factor of the torque converter on the basis of the speed ratio, an input torque calculating device for determining an input torque to the transmission by making use of the torque ratio and the capacity factor, a detection device for detecting an overtorque state by comparing the torque to be applied to the component of the transmission mechanism or a drive mechanism in accordance with the input torque with an allowable torque predetermined for the component, and an output device for outputting a signal to engine torque control device to drop the output torque of the engine in case the overtorque state is detected.

Abstract: In the control of engine output torque for its temporary reduction for change-over of speed stages of an automatic transmission in a vehicle, recovery of the temporarily reduced engine output torque is started when a monitored rotational speed of a rotary member of the automatic transmission approaches its final value to be attained after the completion of the change-over of speed stages across a predetermined border value, and during the recovery the reduction of engine output torque is periodically adjusted in accordance with a difference between a current monitored rotational speed of the rotary member and its final due value so that a current amount of the reduction of engine output torque is decreased along with decrease of the above-mentioned difference.

Abstract: In a hydraulic control system for an automatic transmission comprising a hydraulic servomotor C-2 for a clutch or brake adapted to engage and disengage necessary rotary components of a planetary gear mechanism, and a select valve for selectively supplying hydraulic pressure to the hydraulic servomotor C-2 dependent on two transmission states, the select valve has two input ports selectively supplied with hydraulic pressure dependent on the two transmission states and one output port for outputting hydraulic pressure to the hydraulic servomotor C-2, a first orifice is disposed between the output port and the hydraulic servomotor C-2, and a second orifice is disposed on the same side as either of the two input ports.Upon an upshift from the 2nd to the 3rd speed in the D range condition, a shift valve is changed over such that the line pressure is supplied to one input port of the select valve via a line pressure output port and the second orifice to move a ball valve body in the select valve.

Abstract: In controlling an internal combusion engine so as to temporarily decrease output torque thereof in relation to speed stage shifting of an automatic transmission connected therewith, input rotational speed of the automatic transmission is monitored so as to obtain first and second subsequent time points corresponding to traversing of first and second predetermined values of the input rotational speed along with change thereof due to the speed stage shifting of the transmission, and a control for decreasing engine output torque is triggered at the first time point, while the cancellation of the decreasing of engine output torque is triggered at a time point which is counted by a timer starting from the second time point.