APPARATUS FOR DETECTING ABNORMAL HYDRAULIC PRESSURE OF AUTOMATIC TRANSMISSION

• US 20160017990A1
• Filed: 07/15/2015
• Published: 01/21/2016
• Est. Priority Date: 07/16/2014
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Yoshimura, Yusuke
• Granted Patent: US 9,618,112 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F16H 2059/683 Sensing pressure in control systems or in fluid controlled devices, e.g. by pressure sensors for hydrostatic transmissions F16H2059/6861
• CPC Class Codes: F16H 2061/1208 with diagnostic check cycles; Monitoring of failures
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures

Abstract

In an apparatus for detecting abnormal hydraulic pressure of an automatic transmission having first and second input shafts that input rotation of an engine through first and second clutches and an idler shaft that inputs the rotation through a third clutch, and equipped with a hydraulic pressure supply circuit having a first pressure-regulating valve that generates line pressure, a line pressure-regulating valve that controls operation of the first pressure-regulating valve based on a line pressure command value, and first, second and third hydraulic pressure detectors that detect the hydraulic pressures of first, second and third oil passages respectively, it is determined whether abnormality that makes the high pressure abnormally high has occurred in the line pressure-regulating valve based on the hydraulic pressures detected by at least one of the first, second and third hydraulic pressure detectors and a line pressure command value, when predetermined operating conditions of the vehicle are satisfied.

Claims

1. An apparatus for detecting abnormal hydraulic pressure of an automatic transmission having first and second input shafts that input rotation of a prime mover mounted on a vehicle through first and second clutches;

an idler shaft that inputs the rotation of the prime mover through a third clutch;

at least one output shaft arranged in parallel to the first and second input shafts; and

a plurality of gear engaging mechanisms that engages one of speed gears to the first and second input shafts and the output shaft, comprising;

an oil pump driven by the prime mover;

a hydraulic pressure supply circuit having a first pressure-regulating valve that pressure-regulates hydraulic pressure discharged from the oil pump to line pressure;

a line pressure-regulating valve that controls operation of the first pressure-regulating valve based on a line pressure command value;

second pressure-regulating valve that pressure-regulates the line pressure regulated by the first pressure-regulating valve to clutch pressure;

first and second oil passages that supply the clutch pressure regulated by the second pressure-regulating valve through first and second shift valves to the first and second clutches of the automatic transmission;

a third oil passage that directly supplies the line pressure through the first and second shift valves to the third clutch of the automatic transmission; and

first, second and third hydraulic pressure detectors that detect the hydraulic pressures of the first, second and third oil passages respectively, and

a line-pressure regulating valve abnormality determiner that determines whether abnormality that makes the line pressure abnormally high has occurred in the line pressure-regulating valve based on at least the hydraulic pressures detected by at least one of the first, second and third hydraulic pressure detectors and the line pressure command value, when predetermined operating conditions of the vehicle are satisfied.

2. The apparatus according to claim 1, wherein the predetermined operating conditions are that the rotation of the prime mover is within a predetermined range, that one of the first, second and third clutches of the automatic transmission is engaged, and that the line pressure command value is equal to or less than a prescribed value.

3. The apparatus according to claim 2, wherein the line-pressure regulating valve abnormality determiner determines that the abnormality has occurred in the line pressure-regulating valve when the third clutch is engaged and the hydraulic pressure detected by the third hydraulic pressure detector is greater than the line pressure command value.

4. The apparatus according to claim 2, wherein the line-pressure regulating valve abnormality determiner determines that the abnormality has occurred in the line pressure-regulating valve, if a desired value of the hydraulic pressure to be supplied to the one of the first and second clutches is set to a pressure higher than the line pressure command value and if the hydraulic pressure of the one of the first and second clutches detected by one of the first and second hydraulic pressure detectors is higher than the line pressure command value, when the one of the first and second clutches is engaged.

5. The apparatus according to claim 3, wherein the line-pressure regulating valve abnormality determiner determines that the abnormality has occurred in the line pressure-regulating valve when the hydraulic pressure detected by the third hydraulic pressure detector is kept to be higher than the line pressure command value continuously for a predetermined time period.

6. The apparatus according to claim 4, wherein the line-pressure regulating valve abnormality determiner determines that the abnormality has occurred in the line pressure-regulating valve when the hydraulic pressure of the one of the first and second clutches detected by the one of the first and second hydraulic pressure detectors is kept to be higher than the line pressure command value continuously for a predetermined time period.

7. The apparatus according to claim 1, wherein the predetermined operating conditions include that no gear-shifting of the gear engaging mechanisms of the automatic transmission is in progress.

8. The apparatus according to claim 1, wherein the line-pressure regulating valve abnormality determiner determines the abnormality of the line pressure-regulating valve only once in a driving cycle of the vehicle.