Control apparatus for automatic transmission

Patent metadata

Field	Value
Publication number	US-9709165-B2
Application number	US-201514799772-A
Country	US
Kind code	B2
Filing date	Jul 15, 2015
Priority date	Jul 16, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

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 the automatic transmission is gear-shifted to a predetermined gear at deceleration of the vehicle and it is determined that predetermined operating conditions of the vehicle are satisfied, 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 when the lock-up clutch engaging circuit has been formed, and fail-safe control is then implement when the sticking is determined.

First claim

What is claimed is:

1. An apparatus for controlling an automatic transmission that is connected to a prime mover mounted on a vehicle and changes a speed of rotation of the prime mover to transmit the speed of rotation to driven wheels, the apparatus comprising:
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;
the automatic transmission;
clutches provided on the automatic transmission and connecting the prime mover and the driven wheels;
a controller that controls operation of the lock-up clutch and the automatic transmission through the hydraulic supply circuit; and
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;
wherein the controller forms a lock-up clutch engaging circuit through the hydraulic supply circuit when the automatic transmission is gear-shifted to a predetermined gear at deceleration of the vehicle and it is determined that predetermined operating conditions of the vehicle are satisfied, determines whether an engage-position sticking malfunction of the lock-up clutch has occurred based on the calculated ratio when the lock-up clutch engaging circuit has been formed, and disengages the clutches when it is determined that the engage-position sticking malfunction of the lock-up clutch has occurred.

2. The apparatus according to claim 1 , wherein the controller determines that the engage-position sticking malfunction of the lock-up clutch has occurred, when it is determined that the calculated ratio is kept to be equal to or less than a predetermined ratio for a prescribed time period.

3. The apparatus according to claim 1 , wherein the controller resets data indicative of occurrence of the engage-position sticking malfunction of the lock-up clutch after stop of the vehicle.

4. The apparatus according to claim 1 , wherein the predetermined operating conditions include at least that a lock-up clutch control pressure command value that defines engaging pressure of the lock-up clutch is less than a predetermined value, and that the input rotational speed of the automatic transmission is equal to or greater than a prescribed rotational speed.

5. The apparatus according to claim 1 , wherein the predetermined conditions includes that a temperature of the hydraulic oil of the hydraulic supply circuit is equal to or greater than a predetermined temperature.

Assignees

• Honda Motor Co Ltd

Inventors

• SHIGENAGA Masato
• Takamatsu Masaaki
• Yoshimura Yusuke

Classifications

• F16H61/143

  using electric control means · CPC title

• F16H2061/1224

  Adapting to failures or work around with other constraints, e.g. circumvention by avoiding use of failed parts · CPC title

• F16H2059/467

  of torque converter · CPC title

• F16H61/12 Primary

  Detecting malfunction or potential malfunction, e.g. fail safe (in control of hydrostatic gearing F16H61/4192) {; Circumventing or fixing failures} · CPC title

• F16H61/14

  Control of torque converter lock-up clutches · CPC title