×

Fail-safe operation of a vehicle automatic transmission responsive to failure of engine water temperature sensor

  • US 4,949,078 A
  • Filed: 12/09/1988
  • Issued: 08/14/1990
  • Est. Priority Date: 12/28/1987
  • Status: Expired due to Fees
First Claim
Patent Images

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.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×