Fail-safe operation of a vehicle automatic transmission responsive to failure of engine water temperature sensor
First Claim
1. A fail-safe control device for an electronically controlled automatic transmission having a lock-up clutch comprising:
- (a) means for detecting the number (NE) of engine revolutions or revolutions input to the transmission;
(b) time counting means for measuring duration of engine operation after said number exceeds zero and generating a signal representative of counted time;
(c) an engine water temperature sensor; and
(d) means for receiving said signal and for determining that said engine water temperature sensor is in a failure state when the engine water temperature detected by said engine water temperature sensor, after said counted time exceeds a predetermined time, is lower than a temperature predetermined for said counted time.
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Accused Products
Abstract
A fail-safe control device for an electronically controlled automatic transmission to be mounted on a vehicle arranged in such a manner that the number of engine revolution or the number of revolution input to a T/M is detected, the duration of the engine revolving state is counted, and it is determined that a failure of the engine water temperature sensor occurs if the engine water temperature detected by the engine water temperature sensor after a predetermined time elapse counted is lower than a predetermined temperature. As a result of this, a proper fail-safe control against the failure of the engine water temperature sensor can be performed.
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Citations
7 Claims
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1. A fail-safe control device for an electronically controlled automatic transmission having a lock-up clutch comprising:
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(a) means for detecting the number (NE) of engine revolutions or revolutions input to the transmission; (b) time counting means for measuring duration of engine operation after said number exceeds zero and generating a signal representative of counted time; (c) an engine water temperature sensor; and (d) means for receiving said signal and for determining that said engine water temperature sensor is in a failure state when the engine water temperature detected by said engine water temperature sensor, after said counted time exceeds a predetermined time, is lower than a temperature predetermined for said counted time. - View Dependent Claims (2, 3, 4)
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5. A fail-safe control method for an electronically controlled automatic transmission having a lock-up clutch, provided in a vehicle equipped with an engine water temperature sensor, said method comprising:
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(a) detecting the number (NE) of engine revolutions or revolutions input to the transmission; (b) begin counting elapsed time when said number exceeds zero to obtain a counted elapsed time; and (c) determining that said engine water temperature sensor is in a failure state if the engine water temperature detected by the engine water temperature sensor, after a predetermined elapsed time, is lower than a temperature predetermined for said counted elapsed time. - View Dependent Claims (6, 7)
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Specification