Air ingestion into a transmission hydraulic system may lead to a number of issues. For example, the time to engage a hydraulically actuated parking mechanism may be excessive. As another example, the pump may not prime properly on a subsequent engine start. The air ingestion issue may be detected based on variability of transmission line pressure. When the line pressure variability exceeds a threshold, actions are taken to mitigate the potential issues.

A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. An integrated actuator housing includes a single external power access for the shift actuator. A controller interprets a shaft displacement angle, determines if the transmission is in an imminent zero or zero torque region, and performs a transmission operation in response to the transmission in the imminent zero or zero torque region.

A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. An integrated actuator housing includes a single external power access for the shift actuator. A controller interprets controls the shift actuator with actuating and opposing pulses, and interprets a shaft displacement angle, determines if the transmission is in an imminent zero or zero torque region, and performs a transmission operation in response to the transmission in the imminent zero or zero torque region.

A transmission includes an input shaft and an output shaft, the input shaft selectively accepting a torque input from a prime mover, and the output shaft selectively providing torque output to a driveline. A controller determines a shaft displacement angle representing an angle value of rotational displacement difference between at least two shafts of the transmission, and performs a transmission operation responsive to the shaft displacement angle.

A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. An integrated actuator housing includes a single external power access for the shift actuator. A controller interprets a shaft displacement angle, determines if the transmission is in an imminent zero or zero torque region, and performs a transmission operation in response to the transmission in the imminent zero or zero torque region.

For a hybrid vehicle including an engine, a motor generator, and a belt-type continuously variable transmission, a controller performs a low speed position return expediting control in response to a downshift request accompanying deceleration. During the low speed position return expediting control, the controller increases a differential pressure between a primary pressure and a secondary pressure and cause a downshift toward a lowest speed position transmission ratio by reducing the primary pressure, and further reduces the primary pressure when the secondary pressure becomes greater than or equal to a trigger threshold value during the downshift; and terminates the low speed position return expediting control when an actual secondary pressure decreases to a secondary pressure minimum level. The controller further sets a secondary pressure lower limit higher than the secondary pressure minimum level during the low speed position return expediting control.

A transmission assembly including a clutch system, an accumulator, and a controller is provided. The clutch system may include a flow source. The accumulator may be selectively in communication with the flow source via a solenoid valve. The controller may be programmed to, responsive to detection of a vehicle stop and the accumulator charged below a predetermined threshold, output a command to open the solenoid valve to rapidly charge the accumulator from the flow source. The predetermined threshold may be an accumulator pressure between 700 kPa and 900 kPa. The controller may be further programmed to, responsive to detection of the accumulator being charged to or above the predetermined threshold, output a shut down command to an engine in communication with the transmission assembly and to output a close command to the solenoid valve. The flow source may be a pump out circuit or a line pressure circuit.

In a hydraulic control device and a hydraulic control method of a transmission, in a case that an oil supplying section is supplying a first oil to a continuously variable transmission mechanism, a TCU outputs, to an LC control valve of the oil supplying section, a control signal for giving a command to start supply of a second oil to a torque converter if a pulley pressure detected by a pressure sensor reaches a pressure threshold value.

A transmission (21) as a power transmission device for a vehicle comprises an input shaft (22), an output shaft (23), a planetary continuously variable transmission mechanism (31), a direct connecting mechanism (27), and an idler gear (29). The direct connecting mechanism (27) comprises a direct connecting clutch (30). The planetary continuously variable transmission mechanism (31) comprises a planetary gear mechanism (32), a pump side clutch (33), a hydraulic pump (36), a hydraulic motor (38), and a motor side clutch (40). The hydraulic pump (36) and the hydraulic motor (38) are connected via a pair of main lines (37A, 37B). An electromagnetic on-off valve (41) capable of switching between a communicating state and a blocking state between the pair of main lines (37A, 37B) is provided between the pair of main lines (37A, 37B).

A continuously variable transmission includes: a first pulley and a second pulley each including a fixed pulley and a movable pulley; and an endless member wound around the first pulley and the second pulley, wherein the continuously variable transmission continuously changes a speed ratio by controlling a thrust of the movable pulley with a hydraulic pressure, the thrust of the movable pulley is made smaller as a rotation speed of the first pulley decreases, and when the rotation speed of the first pulley is lower than a predetermined rotation speed, the thrust of the movable pulley in a case where the speed ratio is on a Low side of the predetermined speed ratio is not made smaller than the thrust of the movable pulley in a case where the speed ratio is on a High side of the predetermined speed ratio.