Control method for automatic transmission
AssigneeHyundai Motor Company
InventorHee-Yong Lee
Life of this patent
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Abstract
In a control method for an automatic transmission, it is first determined if the automatic transmission is in a fourth speed and the vehicle is being driven in a power off state, then a damper clutch operation slip control signal is output when the vehicle is in a power off state. Next, an engine fuel cut-in rpm reduction signal is output to engine control unit when a damper clutch is operated by the damper clutch operation slip control signal. A lower engine fuel cut-in signal is transmitted from the engine control unit according to the output engine fuel cut-in rpm reduction signal. Then, it is determined if engine output is undergoing continuous reduction, and a duty ratio is controlled using a learned value during 4-3 shifting when engine output is being reduced.
Claims6
A control method for an automatic transmission comprising the steps of:
- (a) determining if the automatic transmission is in a fourth speed and the vehicle is being driven in a power off state;
- (b) outputting a damper clutch operation slip control signal when the vehicle is in a power off state;
- (c) outputting an engine fuel cut-in rpm reduction signal to an engine control unit when a damper clutch is operated by the damper clutch operation slip control signal;
- (d) receiving an engine fuel cut-in signal from the engine control unit according to the output engine fuel cut-in rpm reduction signal;
- (e) determining if engine output is undergoing continuous reduction;
- and
- (f) controlling a duty ratio using a learned value during 4-3 shifting when engine output is being reduced.
Dependencies are inferred from the claim text.