US 11,754,174 B2
Control device and control method for automatic transmission
Norihira Amano, Fuji (JP); and Masahiro Hamano, Atsugi (JP)
Assigned to JATCO LTD, Fuji (JP); and NISSAN MOTOR CO., LTD., Yokohama (JP)
Appl. No. 17/642,145
Filed by JATCO Ltd, Fuji (JP); and NISSAN MOTOR CO., LTD., Yokohama (JP)
PCT Filed Nov. 20, 2020, PCT No. PCT/JP2020/043399
§ 371(c)(1), (2) Date Jul. 7, 2022,
PCT Pub. No. WO2021/106785, PCT Pub. Date Jun. 3, 2021.
Claims priority of application No. 2019-216986 (JP), filed on Nov. 29, 2019.
Prior Publication US 2022/0333683 A1, Oct. 20, 2022
Int. Cl. B60W 10/11 (2012.01); F16H 61/12 (2010.01); B60W 10/06 (2006.01); B60W 30/18 (2012.01); F16H 61/02 (2006.01); F16H 61/16 (2006.01); F16H 61/682 (2006.01)
CPC F16H 61/12 (2013.01) [B60W 10/06 (2013.01); B60W 10/11 (2013.01); B60W 30/18009 (2013.01); F16H 61/0204 (2013.01); F16H 61/16 (2013.01); F16H 61/682 (2013.01); B60W 2510/0208 (2013.01); B60W 2510/104 (2013.01); B60W 2510/1005 (2013.01); B60W 2510/1015 (2013.01); B60W 2710/0666 (2013.01); B60W 2710/1005 (2013.01); F16H 2061/124 (2013.01); F16H 2061/1232 (2013.01); F16H 2200/0065 (2013.01); F16H 2200/2012 (2013.01); F16H 2200/2046 (2013.01)] 9 Claims
OG exemplary drawing
1. A control device for an automatic transmission, comprising:
a transmission control unit configured to control a shift solenoid provided for each of a plurality of friction elements of a stepped transmission mechanism, and perform a shift control in which a plurality of gear positions are switched by changing engaged states of the plurality of friction elements, wherein
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.