Controller for vehicle power transmission system

Patent metadata

Field	Value
Publication number	US-9689491-B2
Application number	US-201615056063-A
Country	US
Kind code	B2
Filing date	Feb 29, 2016
Priority date	Mar 3, 2015
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

When there is a failure in a speed ratio control linear solenoid valve, or the like, a controller for a vehicle power transmission system establishes a state where torque is transmitted via a gear mechanism, and, in this state, determines whether the speed ratio control linear solenoid valve, or the like, has returned to a normal state by comparing a target speed ratio and actual speed ratio of a continuously variable transmission with each other. It is determined whether the speed ratio control linear solenoid valve, or the like, has returned to the normal state by changing the target speed ratio of the belt-type continuously variable transmission and then comparing the target speed ratio with the actual speed ratio. Thus, when the speed ratio control linear solenoid valve, or the like, has returned from a fail-safe state to the normal state, a feeling of strangeness of a driver is suppressed.

First claim

What is claimed is:

1. A controller for a vehicle power transmission system, the vehicle power transmission system including: a gear mechanism, a belt-type continuously variable transmission and a switching mechanism, the gear mechanism and the belt-type continuously variable transmission being provided in parallel with each other in power transmission paths between an input shaft and an output shaft, the belt-type continuously variable transmission including an input-side sheave and an output-side sheave, the switching mechanism being configured to selectively establish any one of a first transmission path of the power transmission paths and a second transmission path of the power transmission paths, the first transmission path being a path through which torque input from the input shaft is transmitted to the output shaft via the belt-type continuously variable transmission, the second transmission path being a path through which torque input from the input shaft is transmitted to the output shaft via the gear mechanism, the controller comprising:
one or more processors programmed to
calculate an actual speed ratio in the belt-type continuously variable transmission, and
set a target speed ratio of the belt-type continuously variable transmission; and

a hydraulic pressure output device configured to control hydraulic pressure that is output to the input-side sheave based on the target speed ratio, wherein
the one or more processors are further programmed to, when there is a failure in the hydraulic pressure output device, establish a state where torque is transmitted through the second transmission path, and determine whether the hydraulic pressure output device has returned to a normal state by comparing the target speed ratio and actual speed ratio of the belt-type continuously variable transmission with each other in the state where torque is transmitted through the second transmission path.

2. The controller according to claim 1 , wherein
the one or more processors are further programmed to, when there is the failure in the hydraulic pressure output device,
(i) establish the state where torque is transmitted through the second transmission path, and
(ii) determine whether the hydraulic pressure output device has returned to the normal state by changing the target speed ratio of the belt-type continuously variable transmission in the state where torque is transmitted through the second transmission path and then comparing the target speed ratio with the actual speed ratio.

3. The controller according to claim 1 , wherein
the one or more processors are further programmed to, when there is the failure in the hydraulic pressure output device,
(i) establish the state where torque is transmitted through the second transmission path, and
(ii) prohibit switching from the state where torque is transmitted through the second transmission path to a state where torque is transmitted through the first transmission path.

4. The controller according to claim 3 , wherein
the one or more processors are further programmed to, after it is determined that the hydraulic pressure output device has returned to the normal state, when it is determined that a traveling state is a state where the state where torque is transmitted through the second transmission path should be established, cancel prohibition of switching from the state where torque is transmitted through the second transmission path to the state where torque is transmitted through the first transmission path.

5. The controller according to claim 1 , wherein
the one or more processors are further programmed to, when it is determined that there is dice failure in the hydraulic pressure output device,
(i) establish a neutral state in the vehicle power transmission system, and
(ii) at the time when a vehicle speed becomes lower than or equal to a prescribed value, establish the state where torque is transmitted through the second transmission path.

6. The controller according to claim 5 , wherein
the prescribed value is a vehicle speed higher than a vehicle speed that is used as a criterion to switch from a state where torque is transmitted through the first transmission path to the state where torque is transmitted through the second transmission path in the case where it is not determined that there is the failure in the hydraulic pressure output device.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ito Akihide
• Inoue Daisuke
• Fukao Mitsuhiro
• Matsuo Kenji
• Kondo Hiroki
• Kimura Motonori
• Sakamoto Kazuya

Classifications

• F16H37/022

  the toothed gearing having orbital motion · CPC title

• F16H9/18

  only one flange of each pulley being adjustable · CPC title

• F16H61/662

  with endless flexible members · CPC title

• F16H2061/1224

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