US 8,275,510 B2Granted

Failure determining device and failure determining method of continuously variable transmission

AssigneeToyota Jidosha Kabushiki Kaisha

InventorsNaoto Tanaka, Shinya Toyoda, Naoya Inoue, Tadashi Tamura, Akira Hino, Yasunari Matsui

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Abstract

An ECU executes a program including the steps of determining that a change speed solenoid is abnormal when a target speed ratio falls within a predetermined range, an upshift is recognized and the change speed solenoid is abnormal; determining that the change speed solenoid is normal when the change speed solenoid is not abnormal; determining that a belt pinch pressure solenoid is abnormal when the target speed ratio is substantially equal to a speed ratio γmin on a maximum speed-increase side and the target speed ratio is not substantially equal to an actual speed ratio; and determining that the belt pinch pressure solenoid is normal when the target speed ratio is substantially equal to the actual speed ratio.

Claims10

Dependent claims

A failure determining device of a continuously variable transmission mounted on a vehicle, wherein said continuously variable transmission includes a drive pulley, a driven pulley and a belt, said belt is wound around said drive and driven pulleys, a speed ratio is continuously changed by changing winding radii of said belt around said pulleys, said pulleys have groove widths being changeable by actuators supplied with a hydraulic pressure regulated by a regulator valve, and said regulator valve includes a first regulator valve for regulating a hydraulic pressure supplied to the actuator of said drive pulley and a second regulator value for regulating the hydraulic pressure supplied to the actuator of said driven pulley;

said failure determining device comprises:
a sensing unit for sensing a physical quantity corresponding to a running state of said vehicle, and
a determining unit connected to said sensing unit;
said determining unit determines whether said first regulating valve is abnormal in a region where the hydraulic pressure supplied to the actuator of said driven pulley is higher than the hydraulic pressure supplied to the actuator of said drive pulley, or not, at the time of changing speed ratio in a first region of the speed ratio based on a degree of change of an actual speed ratio calculated based on a running state corresponding to said sensed physical quantity and the target speed ratio;
said determining unit determines whether said second regulating valve is abnormal in a region where the hydraulic pressure supplied to the actuator of said driven pulley is lower than the hydraulic pressure supplied to the actuator of said drive pulley, or not, at the time of changing speed ratio change in a second region on a speed increase side with respect to said first region, based on the degree of change of the actual speed ratio calculated based on said running state and the target speed ratio;
and
said first and second regions do not overlap together, and each of said first and second regions allows the change of speed ratio when said second regulating valve is abnormal.

4 more elements

A failure determining method of a continuously variable transmission mounted on a vehicle, wherein said continuously variable transmission includes a drive pulley, a driven pulley and a belt, said belt is wound around said drive and driven pulleys, a speed ratio is continuously changed by changing winding radii of said belt around said pulleys, said pulleys have groove widths being changeable by actuators supplied with a hydraulic pressure regulated by a regulator valve, and said regulator valve includes a first regulator valve for regulating a hydraulic pressure supplied to the actuator of said drive pulley and a second regulator value for regulating the hydraulic pressure supplied to the actuator of said driven pulley;

said failure determining method comprises:
a sensing step of sensing a physical quantity corresponding to a running state of said vehicle;
a first determining step of determining whether said first regulating valve is abnormal or not, at the time of changing speed ratio in a first region of the speed ratio, based on a degree of change of an actual speed ratio calculated based on a running state corresponding to said sensed physical quantity and the target speed ratio;
and
a second determining step of determining whether said second regulating valve is abnormal or not, at the time of changing speed ratio in a second region on a speed increase side with respect to said first region based on the degree of change of the actual speed ratio calculated based on said running state and the target speed ratio;
said first determining step determines whether said first regulating valve is abnormal in a region where the hydraulic pressure supplied to the actuator of said driven pulley is higher than the hydraulic pressure supplied to the actuator of said drive pulley, or not;
said second determining step determines whether said second regulating valve is abnormal in a region where the hydraulic pressure supplied to the actuator of said driven pulley is lower than the hydraulic pressure supplied to the actuator of said drive pulley, or not;
and
said first and second regions do not overlap together, and each of said first and second regions allows the change of speed ratio when said second regulating valve is abnormal.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/670,470Filed 25 Jul 2008
Priority: JP 2007-19577427 Jul 2007
Published: US 2010/0191407 A129 Jul 2010
Granted: 25 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

F16H 61/12
Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid…
F16H 61/66259
Controlling of shifting being influenced by a signal derived from the engine and the main coupling: using electrical or electronical sensing or…
F16H 61/66272
With endless flexible members: characterised by means for controlling the torque transmitting capability of the gearing
F16H 59/70
Inputs being a function of gearing status: dependent on the ratio established