Abstract: A hydraulic control apparatus of a vehicular automatic transmission has a plurality of hydraulic friction engagement devices that are selectively engaged and released to establish a plurality of forward speed change stages of different speed change ratios. The forward speed change stages are achieved through engagement of predetermined friction engagement devices, of the plurality of friction engagement devices. If it is determined that a predetermined speed change stage corresponding to a predetermined shift output is not established, the hydraulic control apparatus identifies a hydraulic friction engagement device having a bad engagement that is a cause of the non-establishment of the predetermined speed change stage, on the basis of the state of engagement oil pressure of the predetermined friction engagement device.

Abstract: When a traveling state is in an engagement range of a lock-up clutch, an ECU executes a program including a step of executing slip control if preconditions are satisfied and learning start conditions are satisfied, a step of updating a learning value if an output value is not greater than an FF control value+? or not smaller than the FF control value+?, and a step of engaging the lock-up clutch.

Abstract: The vehicle start determining unit determines a vehicle starting state based on a vehicle speed and an accelerator pedal press-down degree. When the vehicle starting state is determined, the target slip value determining unit determines a target slip rotational speed based on the actual accelerator pedal press-down degree. In receipt of a signal indicating initiation of the control upon the previous slip control, the running history storing unit stores a change of the vehicle speed over time after the relevant timing, and sets a running history flag to an on state when detecting that the vehicle speed has exceeded a prescribed threshold value. In receipt of the target slip rotational speed and the running history flag, if the running history flag is in the on state, the lock-up clutch control unit carries out the slip control according to the target slip rotational speed.

Abstract: A hydraulic control apparatus for switching an operation of a hydraulically operated mechanical apparatus, by selectively operating two frictional engagement elements of a first, a second, a third, and a fifth frictional engagement elements, the hydraulic control apparatus including a first control valve which, in association with an event that respective hydraulic pressures to operate the first and second frictional engagement elements are both produced, drains one of the third and fifth frictional engagement elements and outputs a control hydraulic pressure; and a second control valve which, when at least two hydraulic pressures of (a) the control hydraulic pressure and (b) respective hydraulic pressures to operate the third and fifth frictional engagement elements are supplied to the second control valve, drains the other of the third and fifth frictional engagement elements.

Abstract: An overflow tube is provided at an oil pan and when the oil pan receives an amount of a working fluid exceeding a prescribed amount the overflow tube causes the fluid to overflow to allow the fluid to have a level set at a prescribed level. The overflow tube has an end portion positioned in the oil pan and defining an opening of a drain hole receiving and passing the fluid overflowing. The end portion has a curved surface facing vertically upward and extending to surround the opening of the drain hole, and curving in a direction in contact with a generally horizontal direction. The overflow tube can thus help to set the fluid's level at a prescribed level precisely.

Abstract: A shift control apparatus of an automatic transmission of a motor vehicle to which torque is transmitted from an engine via a fluid coupling device is provided. In the automatic transmission including a plurality of hydraulically operated friction elements, a clutch-to-clutch downshift is carried out during coasting of the vehicle by releasing one of the friction elements and engaging another friction element. A controller of the shift control apparatus detects a difference between input and output rotation speeds of the fluid coupling device, and increases an engine speed by a controlled amount based on the difference between the input and output rotation speeds when the clutch-to-clutch downshift is carried out during coasting of the vehicle, so that the vehicle is brought into a minimal driving state in which the engine speed is slightly higher than the output rotation speed of the fluid coupling device.

Abstract: In a friction engagement device of an automatic transmission, a brake piston is actuated by an oil pressure and a friction disc is pressed by the brake piston. The friction engagement device of an automatic transmission includes an oil pressure chamber extending in an annular shape and a main oil pressure supply path and a secondary oil pressure supply path each extending separately to supply oil to the oil pressure chamber. Each of the main oil pressure supply path and secondary oil pressure supply path connects to the oil pressure chamber in a position different from each other in a circumferential direction of the oil pressure chamber. With a construction as such, a friction engagement device of an automatic transmission is provided which prevents a load to the friction disc from locally increasing and attains a smooth speed-changing operation.

Abstract: A lubrication structure of a transmission includes a gear chamber having an internal space storing lubricating oil, in which chamber a pressure is raised to a prescribed pressure, a gear chamber having an internal space communicating to the internal space through a communicating hole and attaining a pressure lower than the prescribed pressure, and an oil catch tank provided in the internal space at a position directly under the communicating hole and receiving the lubricating oil that flows into the internal space from the internal space through the communicating hole. With such a structure, a lubrication structure for a transmission capable of holding an oil level at a proper level with a simplified structure can be provided.

Abstract: In a shift control system of an automatic transmission for a vehicle, an engaging torque applied to a predetermined friction element that has been engaged to establish a predetermined gear stage of the automatic transmission during running of the vehicle is gradually decreased to generate a slip in the predetermined friction element. Based on the engagigng torque of the friction element and a command value output to generate the engaging torque to the friction element, a predetermined relationship used for determining the command value for generating a required engaging torque is corrected. Learning quality or accuracy with respect to the predetermined relationship between the engaging torque of the friction element and the control value for generating the engaging torque may be sufficiently ensured.

Abstract: In a control apparatus for a vehicle, when a coast downshifting is performed in response to a downshifting command from a vehicle operator during braking operation under the fuel cut control, the braking force of the wheel brake is increased so as to increase the deceleration. This makes it possible to achieve a predetermined deceleration with a good response to the deceleration request of the vehicle operator represented by the downshifting command. The control apparatus is structured to decrease the braking force of the wheel brake such that the increase in the engine braking force is offset by the inertia caused by the rise in the engine speed resulting from downshifting upon the coast downshifting due to the vehicle speed increase. The control apparatus for the vehicle, thus, reduces the shock caused by the sharp increase in the engine braking force.

Abstract: A duty ratio for controlling an engagement force of a friction engagement device on the side of upshift engagement is corrected by an amount corresponding to an intermediate correction control value in the course of the shift. In addition, on a prerequisite condition that learning correction of a constant standby pressure control value at the start of the shift is converged, learning correction is performed for the intermediate correction control value according to a gradient of a turbine speed. Thus, a shift shock is prevented from occurring due to abrupt engagement of the friction engagement device and the like at the completion of the shift.

Abstract: When it has been determined that control for a predetermined upshift has been started while an accelerator pedal was not being depressed, and that a factor that changes an input torque of an automatic transmission has been generated, an engaging pressure of a predetermined hydraulic frictional engagement device is corrected by a correction amount in accordance with the factor that changes the input torque. As a result, undershooting of an engine speed, as well as shift shock which results from that undershooting, is able to be preferably suppressed.

Abstract: In a vehicle in which a moderate throttle opening degree control of maintaining a degree of throttle opening that is less than a degree of throttle opening that corresponds to an accelerator operation is performed for a predetermined period following a beginning of the accelerator operation, if it is determined that a clutch-to-clutch downshift judgment has been made, the reduction of the engaging pressure of a disengage-side friction engagement device is restrained until it is determined that the moderate throttle opening degree control has ended. Therefore, even if the turbine torque is returned to a normal value at the end of the moderate throttle opening degree control, insufficient engaging torque is avoided, and the takeover of engaging torque for the clutch-to-clutch downshift is smoothly performed while the turbine torque is stable. Hence, occurrence of a shock related to the end of the moderate throttle opening degree control is suitably prevented.

Abstract: A hydraulic control apparatus for switching an operation of a hydraulically operated mechanical apparatus, by selectively operating two frictional engagement elements of a first, a second, a third, and a fifth frictional engagement elements, the hydraulic control apparatus including a first control valve which, in association with an event that respective hydraulic pressures to operate the first and second frictional engagement elements are both produced, drains one of the third and fifth frictional engagement elements and outputs a control hydraulic pressure; and a second control valve which, when at least two hydraulic pressures of (a) the control hydraulic pressure and (b) respective hydraulic pressures to operate the third and fifth frictional engagement elements are supplied to the second control valve, drains the other of the third and fifth frictional engagement elements.

Abstract: An automatic transmission and method including a plurality of hydraulic servos which respectively engage and disengage a plurality of frictional engagement elements, a first solenoid valve for gear shifting which is used for generating a hydraulic pressure supplied to a predetermined hydraulic servo, a second solenoid valve for lock-up which is used for generating a hydraulic pressure supplied to a fluid transmission apparatus for executing a lock-up, a hydraulic control apparatus, a first connector which connects the first solenoid valve and the hydraulic control apparatus, a second connector which connects the second solenoid valve and the hydraulic control apparatus, a failsafe mechanism which achieves a predetermined shift range in a high-speed-side when the first connector is disconnected and a gear shift processing mechanism which achieves a predetermined shift range among a plurality of shift ranges when the second connector is disconnected.

Abstract: In a vehicle having a hydraulic power transmitting device equipped with a lock-up clutch on an output side of the engine, a control apparatus for controlling the lock-up clutch is provided which includes a lock-up clutch control unit that places the lock-up clutch in a slipping state when the vehicle is started so that torque received from the engine is transmitted to a later-stage transmission via the lock-up clutch as well as the hydraulic power transmitting device.

Abstract: In a shift control system of an automatic transmission for a vehicle, an engaging torque applied to a predetermined friction element that has been engaged to establish a predetermined gear stage of the automatic transmission during running of the vehicle is gradually decreased to generate a slip in the predetermined friction element. Based on the engagigng torque of the friction element and a command value output to generate the engaging torque to the friction element, a predetermined relationship used for determining the command value for generating a required engaging torque is corrected. Learning quality or accuracy with respect to the predetermined relationship between the engaging torque of the friction leement and the control value for generating the engaging torque may be sufficiently ensured.

Abstract: A shift control apparatus of an automatic transmission of a motor vehicle to which torque is transmitted from an engine via a fluid coupling device is provided. In the automatic transmission including a plurality of hydraulically operated friction elements, a clutch-to-clutch downshift is carried out during coasting of the vehicle by releasing one of the friction elements and engaging another friction element. A controller of the shift control apparatus detects a difference between input and output rotation speeds of the fluid coupling device, and increases an engine speed by a controlled amount based on the difference between the input and output rotation speeds when the clutch-to-clutch downshift is carried out during coasting of the vehicle, so that the vehicle is brought into a minimal driving state in which the engine speed is slightly higher than the output rotation speed of the fluid coupling device.

Abstract: When a clutch is disengaged in a D-N shift, a duty ratio of a linear solenoid in a stand-by state at a constant pressure is calculated according to the following equation by using the following values: a reference duty ratio in a stand-by state at a constant pressure; a correction value for an AT oil temperature; a correction value for an engine speed; and respective learning correction values in a N-D shift and a 4-3 coast down shift in which the clutch is engaged. In the equation, K is a coefficient and has a constant value predetermined in the range of 0≦K≦1.

Abstract: To prevent the neutral state from being formed in a change gear apparatus and allow the obtaining of an intended gear change appropriately during a servo malfunction. Hydraulic servos engage and disengage a plurality of friction engagement elements; a hydraulic pressure supply system supplies the hydraulic servo of a predetermined friction engagement element with hydraulic pressure; and an auxiliary hydraulic pressure supply systems supplies a predetermined hydraulic servo with another hydraulic pressure, in the case where the hydraulic pressure supply system is placed in a first unsupplied state where the hydraulic pressure supply system cannot supply the hydraulic servo of the predetermined friction engagement element with hydraulic pressure.