Method for diagnosing a failure of an output shaft speed sensor of an automatic transmission for a vehicle
First Claim
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1. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
- determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on at least one of a current gear, an input shaft speed, an output shaft speed, or an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a gear if an upshift criterion exists, if the failure criterion exists, wherein if the determined forward gear is first gear or second gear, the failure criterion comprises at least one of;
(1) a lapse of a predetermined period after shifting from neutral to drive and a turbine shaft speed greater than a turbine shaft speed threshold and no signal from the output shaft speed sensor; and
(2) a lapse of a predetermined period after shifting from neutral to drive and an engine speed greater than a engine speed threshold and a normal engine speed sensor signal and no signal from the output shaft speed sensor.
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Abstract
A method and apparatus for diagnosing a failure of an output shaft speed sensor of an automatic transmission is provided, which comprises: determining whether a current transmission is a forward driving range; determining whether a failure criterion exists based on a current gear, an input shaft speed, an output shaft speed, and an engine speed, if the current transmission is the forward driving range; and maintaining the current gear if a downshift criterion exists, or upshifting a gear if a upshift criterion exists, if the failure criterion exists.
13 Citations
29 Claims
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1. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on at least one of a current gear, an input shaft speed, an output shaft speed, or an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a gear if an upshift criterion exists, if the failure criterion exists, wherein if the determined forward gear is first gear or second gear, the failure criterion comprises at least one of;
(1) a lapse of a predetermined period after shifting from neutral to drive and a turbine shaft speed greater than a turbine shaft speed threshold and no signal from the output shaft speed sensor; and
(2) a lapse of a predetermined period after shifting from neutral to drive and an engine speed greater than a engine speed threshold and a normal engine speed sensor signal and no signal from the output shaft speed sensor. - View Dependent Claims (2)
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3. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on at least one of a current gear, an input shaft speed, an output shaft speed, or an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a gear if an upshift criterion exists, if the failure criterion exists, wherein if the determined forward gear is first gear or second gear, the failure criterion comprises at least one of;
(1) a lapse of a predetermined period after shifting from neutral to drive and a turbine shaft speed greater than a turbine shaft speed threshold and no signal from the output shaft speed sensor; and
(2) a lapse of a predetermined period after shifting from neutral to drive and an engine speed greater than a engine speed threshold and a normal engine speed sensor signal and no signal from the output shaft speed sensor and, wherein if the transmission is determined to be in third gear, fourth gear, or fifth gear, the failure criterion comprises at least one of;
(1) completion of shifting from neutral to drive, and a turbine shaft speed greater than a turbine shaft speed threshold, and no signal from the output shaft speed sensor; and
(2) completion of shifting from neutral to drive, and an engine speed greater than an engine speed threshold, and a normal engine speed sensor signal, and no signal from the output shaft speed sensor. - View Dependent Claims (4)
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5. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on at least one of a current gear, an input shaft speed, an output shaft speed, or an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a wear if an upshift criterion exists, if the failure criterion exists, wherein if the determined forward gear is first gear or second gear, the failure criterion comprises at least one of;
(1) a lapse of a predetermined period after shifting from neutral to drive and a turbine shaft speed greater than a turbine shaft speed threshold and no signal from the output shaft speed sensor; and
(2) a lapse of a predetermined period after shifting from neutral to drive and an engine speed greater than a engine speed threshold and a normal engine speed sensor signal and no signal from the output shaft speed sensor, wherein if the transmission is determined to be in third gear, fourth gear, or fifth gear, the failure criterion comprises at least one of;
(1) completion of shifting from neutral to drive, and a turbine shaft speed greater than a turbine shaft speed threshold, and no signal from the output shaft speed sensor; and
(2) completion of shifting from neutral to drive, and an engine speed greater than an engine speed threshold, and a normal engine speed sensor signal, and no signal from the output shaft speed sensor and, wherein the upshift criterion comprises at least one of;
(1) an engine speed greater than an engine speed threshold, and an angular acceleration of the engine greater than 0; and
(2) a turbine shaft speed greater than a turbine shaft speed threshold, and an angular acceleration of the turbine shaft greater than 0.
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6. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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(a) determining whether the transmission is in a forward gear;
(b) determining whether a failure criterion exists based on at least one of a current gear, an input shaft speed, an output shaft speed, or an engine speed, if the transmission is in a forward gear;
(c) maintaining the current gear if a downshift criterion exists, or upshifting a gear if an upshift criterion exists, if the failure criterion exists, wherein if the determined forward gear is first gear or second gear, the failure criterion comprises at least one of;
(1) a lapse of a predetermined period after shifting from neutral to drive and a turbine shaft speed greater than a turbine shaft speed threshold and no signal from the output shaft speed sensor; and
(2) a lapse of a predetermined period after shifting from neutral to drive and an engine speed greater than a engine speed threshold and a normal engine speed sensor signal and no signal from the output shaft speed sensor, wherein if the transmission is determined to be in third gear, fourth gear, or fifth gear, the failure criterion comprises at least one of;
(1) completion of shifting from neutral to drive, and a turbine shaft speed greater than a turbine shaft speed threshold, and no signal from the output shaft speed sensor; and
(2) completion of shifting from neutral to drive, and an engine speed greater than an engine speed threshold, and a normal engine speed sensor signal, and no signal from the output shaft speed sensor and, wherein the upshift criterion comprises at least one of;
(1) an engine speed greater than an engine speed threshold, and an angular acceleration of the engine greater than 0; and
(2) a turbine shaft speed greater than a turbine shaft speed threshold, and an angular acceleration of the turbine shaft greater that 0, further comprising;
(d) determining whether a shift restriction criterion exists;
(e) determining whether the transmission is in a forward gear, if it is determined that the shift restriction criterion exists; and
(f) maintaining a current gear if a downshift criterion exists, or upshifting a gear if a upshift criterion exists, for a shift restriction period, if the transmission is in a forward gear. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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an inhibitor switch for detecting what gear the transmission is in;
an input shaft speed sensor detecting a turbine shaft speed and generating a corresponding signal;
an output shaft speed sensor detecting an output shaft speed and generating a corresponding signal;
an engine speed sensor detecting an engine speed and generating a corresponding signal; and
a control unit programmed to execute instructions comprising;
determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on a current gear, an input shaft speed, an output shaft speed, and an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a gear if a upshift criterion exists, if the failure criterion exists. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification