A hydraulic control apparatus including a first and second control valves switched to exert hydraulic pressure on a piston to press toward first position, a third and fourth control valves switched to exert hydraulic pressure on the piston to press toward second position and, a CPU. The CPU performs executing a first process controlling the control valves so that hydraulic pressure is exerted by switching of the first, second and third control valves or a second process controlling the control valves so that hydraulic pressure is exerted by switching of the second control valve and determining that the first control valve is failed when movement of the piston to the first position is not detected through the first process and determining that the third control valve is failed when movement of the piston to the first position is not detected through the second process.

A monitoring method and device for determination of a gear-stick position, a vehicle control unit, and a vehicle. The monitoring method for determination of a gear-stick position includes: acquiring a first actual gear-stick position and a first acceptable gear-stick position calculated by a functional layer; calculating a second actual gear-stick position according to a gear-stick position signal; determining whether the first actual gear-stick position and the second actual gear-stick position are consistent; in case that the first actual gear-stick position and the second actual gear-stick position are consistent, determining whether the first acceptable gear-stick position is valid; and in case that the first actual gear-stick position and the second actual gear-stick position are inconsistent or the first acceptable gear-stick position is invalid, controlling the vehicle to enter a safe state. The present application can ensure safe driving of a vehicle.

The transmission control unit includes a gear ratio abnormality determination unit and a limp home control unit. The gear ratio abnormality determination unit is configured to determine that a gear ratio is abnormal when, during travelling at a predetermined gear position, a difference between an actual gear ratio, which is calculated based on a transmission input shaft rotation speed and a transmission output shaft rotation speed, and a set gear ratio at the predetermined gear position is equal to or greater than a set value. The limp home control unit is configured to, when the gear ratio abnormality determination unit determines that the gear ratio is abnormal, output a disengagement instruction for disengaging all of the plurality of friction elements, when it is confirmed that a neutral state is shifted to according to the output of the disengagement instruction, determine engagement/disengagement of a specific friction element among the plurality of friction elements based on rotation/stop information of a rotation member of the stepped transmission mechanism, and determine an evacuation gear position based on determination information on the engagement/disengagement of the specific friction element, and shift the gear position to the determined evacuation gear position.

Disclosed is method for operating a multi-gear vehicle transmission having a plurality of shifting elements (A, B, C, D, E) for engaging gears of the vehicle transmission. In a neutral gear a transmission input (1) and a transmission output (2) of the vehicle transmission are decoupled from one another. In a driving gear the transmission input (1) and the transmission output (2) of the vehicle transmission are coupled with one another by closing the shifting elements (A, B, C, D, E) associated with the driving gear in order to propel the vehicle. When the neutral gear is engaged, a transmission condition is determined, and if a transmission condition with elevated drag losses exists, then in addition to the shifting elements (A, B, C, D, E) of a driving gear, at least one further shifting element (A, B, C, D, E) of the vehicle transmission is closed.

A control device for an automatic transmission includes: a failure diagnosis section for diagnosing whether or not a failure has occurred in a shift control system of the automatic transmission; a fail-safe control section for fixing the automatic transmission into a predetermined gear position in response to confirmation of the failure of the shift control system of the automatic transmission; and an oil temperature rise regulation torque reduction control section for outputting a torque reduction request to suppress torque of a vehicle driving source, based on temperature of transmission operating oil of the automatic transmission, and outputting the torque reduction request in response to satisfaction of an oil temperature condition that is set lower in oil temperature when the automatic transmission is fixed in a first gear position by the fail-safe control section than when the automatic transmission is not fixed in the first gear position.

In an apparatus for controlling an automatic transmission connected to a prime mover mounted on a vehicle, having a torque converter equipped with a lock-up clutch, when predetermined operating conditions of the vehicle are satisfied at drive-off, a lock-up clutch engaging circuit is formed through a hydraulic supply circuit. Next it is determined whether engage-position sticking malfunction of the lock-up clutch has occurred based on a ratio of an input rotational speed of the automatic transmission relative to an output rotational speed of the prime mover and a change rate of the output rotational speed of the prime mover when the lock-up clutch engaging circuit has been formed, and fail-safe control is then implement when the sticking is determined.

There is obtained an automatic transmission control apparatus that makes it possible that even when an abnormality occurs in a sensor for detecting a motor rotation angle or the like, control of an automatic transmission is appropriately performed. Inputted first, second, and third detection signals are compared with one another; it is determined that at least two detection signals, out of these detection signals, that coincide with each other are normal and another detection signal is abnormal; then, based on the result of the determination, switching of the ranges of the automatic transmission is controlled.

A vehicle includes a prime mover, transmission, drive axle, and controller. The controller identifies clutches involved in establishing or maintaining a requested gear state, and detects an impending fault condition of the transmission. The controller also executes a pre-remedial control action in response to the impending fault condition, and places the transmission in a hydraulic default mode when the remedial control action does not clear the fault condition after a calibrated duration. A system includes the transmission and controller. A method for providing pre-remedial control of a transmission includes identifying clutches of the transmission that are involved in establishing or maintaining a requested gear state, and detecting an impending fault condition. The method further includes executing a pre-remedial control action in response to the impending fault condition and placing the transmission in a hydraulic default mode if the remedial control action does not clear the fault condition.

A vehicle includes a prime mover, a transmission having an electronic transmission range selection (ETRS) system, a user interface device that generates an electric range selection (ERS) signal in response to a selected operating range, and a controller. The controller processes the ERS signal and determines the operating range and executes a remedial control action when the incorrect powerflow is detected. The remedial action may include interrupting powerflow. A control apparatus includes the user interface device and controller. A method includes determining if a powerflow fault condition is present, including comparing clutches commanded on against a calibrated list of clutches not permitted to be on, and one or both of comparing a measured speed ratio to an expected speed ratio and comparing actual switch states of mode valves to states commanded by the ETRS system. The method includes executing the remedial control action when the incorrect powerflow is detected.

Even when a motor fails in an EV travel mode in which a clutch is disengaged, an amount of hydraulic oil that is supplied to the clutch can be secured by reducing a transmission leaked amount. Accordingly, the clutch can be engaged, and an oil pump can be driven by power of an engine. Thus, an evacuation travel by the engine is allowed when the motor fails in the EV travel mode.