Abstract: A hydraulic control device that controls a hydraulic pressure for a plurality of friction engagement elements included in an automatic transmission mounted on a vehicle to establish a plurality of shift speeds, including: a plurality of pressure regulation valves, a plurality of hydraulic switches, speed change control means, and abnormality determination means.

Abstract: A hydraulic control device that controls a hydraulic pressure for a plurality of friction engagement elements included in an automatic transmission mounted on a vehicle to establish a plurality of shift speeds, including: a plurality of pressure regulation valves, a plurality of hydraulic switches, speed change control means, and abnormality determination means.

Abstract: An oil pressure control apparatus for an automatic transmission configured with an oil pressure servo that engages and disengages a friction engagement element. The friction element is engaged by first and second hydraulic oil chambers that individually provide low torque, and can provide a higher torque when working in combination. A failure solenoid valve outputs a signal when a failure occurs to stop oil pressure to an oil pressure servo. Valves are configured to determine whether oil pressure is supplied to or discharged from the first and second hydraulic oil chambers. A switching valve is switched on the basis of the failure signal, and an oil pressure can be individually supplied to and discharged from the first and second hydraulic oil chambers based on the status of the switching solenoid valve and the signal from the failure solenoid valve.

Abstract: An oil pressure control apparatus for an automatic transmission configured with an oil pressure servo that engages and disengages a friction engagement element. The friction element is engaged by first and second hydraulic oil chambers that individually provide low torque, and can provide a higher torque when working in combination. A failure solenoid valve outputs a signal when a failure occurs to stop oil pressure to an oil pressure servo. Valves are configured to determine whether oil pressure is supplied to or discharged from the first and second hydraulic oil chambers. A switching valve is switched on the basis of the failure signal, and an oil pressure can be individually supplied to and discharged from the first and second hydraulic oil chambers based on the status of the switching solenoid valve and the signal from the failure solenoid valve.

Abstract: A system for control of the discharge pressure of an input clutch hydraulic servo at the time of a D→N shift, in which the peak value (DN_Omega_max) rate of change of the rotational speed of an input shaft increases if the initial value (DN sol Sweep Start SLT signal) of the pressure adjusting control becomes high or low. A convergence region (DN_Omega_limit_max) is provided. On the basis of comparison between the previous peak value (DN_Omega_max_ave1) and the present peak value (DN_Omega_max_ave2), and the direction of correction, the learning is performed in accordance with various maps in a direction toward the convergence region.

Abstract: A system for control of the discharge pressure of an input clutch hydraulic servo at the time of a D→N shift, in which the peak value (DN_Omega_max) rate of change of the rotational speed of an input shaft increases if the initial value (DN sol Sweep Start SLT signal) of the pressure adjusting control becomes high or low. A convergence region (DN_Omega_limit_max) is provided. On the basis of comparison between the previous peak value (DN_Omega_max_ave1) and the present peak value (DN_Omega_max_ave2), and the direction of correction, the learning is performed in accordance with various maps in a direction toward the convergence region.