Control system and method for an automatic transmission providing smooth engagement action
This patent describes an automatic transmission system for a vehicle, the automatic transmission system comprising a gear transmission mechanism which comprises a rotational element, and first and second friction engaging means which are oppositely changed over between engaged and disengaged states so as to alternately provide one of a first speed stage and a second speed stage of the gear transmission mechanism, a control system comprising: first means for detecting a rotational speed of the rotational element; second means for controlling an engagement and disengagement of the first friction engaging means so as to increase a degree of engagement of the first friction engaging means when activated in one of first and second actuating directions thereof and to decrease the degree of engagement of the first friction engaging means when activated in the other of the first and second actuating directions: third means for repetitively comparing each current value of the rotational speed of the rotational element detected by the first means with a preceding value of the rotational speed of the rotational element detected by the first means in the repetitive comparison; fourth means for activating the second means to incrementally activate the second means in one of the first and second actuating directions each time the third means detects in the repetitive comparison.
- Assignee:
- Toyota Jidosha Kabushiki Kaisha, Toyota
- Patent Number(s):
- US 4685356
- OSTI ID:
- 6095673
- Country of Publication:
- United States
- Language:
- English
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