US 9,810,319 B2
Control apparatus for automatic transmission
Masato Shigenaga, Wako (JP); and Yusuke Yoshimura, Wako (JP)
Assigned to HONDA MOTOR CO., LTD, Tokyo (JP)
Filed by HONDA MOTOR CO., LTD, Minato-ku, Tokyo (JP)
Filed on Jul. 13, 2015, as Appl. No. 14/797,440.
Claims priority of application No. 2014-145895 (JP), filed on Jul. 16, 2014.
Prior Publication US 2016/0017988 A1, Jan. 21, 2016
Int. Cl. F16H 61/12 (2010.01); F16H 61/14 (2006.01)
CPC F16H 61/12 (2013.01) [F16H 61/143 (2013.01); F16H 2061/1224 (2013.01); F16H 2061/1232 (2013.01)] 15 Claims
OG exemplary drawing
 
1. An apparatus for controlling an automatic transmission that is connected to a prime mover mounted on a vehicle and changes speed of rotation of the prime mover to transmit the speed of rotation to driven wheels, having a torque converter interposed between the prime mover and the automatic transmission and equipped with a lock-up clutch, a hydraulic supply circuit that supplies hydraulic pressure to the lock-up clutch and the automatic transmission, and a controller that controls operation of the lock-up clutch and the automatic transmission through the hydraulic supply circuit, comprising:
a rotational speed ratio calculator that calculates a ratio of an input rotational speed of the automatic transmission relative to an output rotational speed of the prime mover; and
a lock-up clutch engage-position sticking determiner that causes the controller to form a lock-up clutch engaging circuit through the hydraulic supply circuit when it is determined that predetermined operating conditions of the vehicle are satisfied at vehicle drive-off, determines whether engage-position sticking malfunction of the lock-up clutch has occurred based on the calculated ratio and a change rate of the output rotational speed of the prime mover when the lock-up clutch engaging circuit has been formed, and causing the controller to implement fail-safe control when the sticking is determined.