Failsafe system in automatic transmission
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsKunihiro Iwatsuki, Yoshio Shindo
Life of this patent
Estimating the term…
Abstract
A failsafe system in an automatic transmission includes: a device for detecting rotary speed of an output shaft of the automatic transmission; a device for detecting either rotary speed of a rotary member other than the output shaft of the automatic transmission or engine rotary speed. When a correlation between the output shaft rotary speed and either the rotary speed of the rotary member or the engine rotary speed is abnormal, control oil pressure in a hydraulic control device of the automatic transmission is increased, whereby slippage in frictionally engaging devices in the hydraulic control device of the automatic transmission during non-shift are effectively eliminated.
Claims8
A failsafe system in an automatic transmission for a vehicle, comprising:
- means for detecting an output shaft rotary speed of said automatic transmission;
- means for detecting engine rotary speed;
- means for detecting engine load;
- means for detecting whether a lockup clutch of said automatic transmission is engaged;
- means for detecting whether a prescribed period of time has elapsed from either a shift judgment or a shift command of said automatic transmission;
- means for determining a correlation between said output shaft rotary speed and said engine rotary speed when said engine load is higher than a predetermined value, said lockup clutch is engaged, and said prescribed period of time has elapsed from either of said shift judgment or shift command of said automatic transmission;
- means for judging whether said correlation is abnormal;
- and
- means for increasing oil pressure in a hydraulic control device of said automatic transmission when said correlation is judged to be abnormal.
A failsafe system in an automatic transmission for a vehicle, comprising:
- means for detecting rotary speed of an output shaft of said automatic transmission;
- means for detecting rotary speed of a turbine shaft of said automatic transmission;
- means for detecting engine load;
- means for detecting whether a prescribed period of time has elapsed from either a shift judgment or a shift command of said automatic transmission;
- means for determining a correlation between the rotary speed of the output shaft and the rotary speed of the turbine shaft when said engine load is higher than a predetermined value, and said prescribed period of time has elapsed from either of said shift judgment or shift command of said automatic transmission;
- means for judging whether said correlation is abnormal;
- and
- means for increasing oil pressure in a hydraulic control device of said automatic transmission when said correlation is judged to be abnormal.
Dependencies are inferred from the claim text.