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US 10,731,751 B2Granted
Automatic gear changer control device and control method
AssigneesJATCO Ltd, Nissan Motor Co., Ltd.
InventorsKunihiko Okumura, Takeshi Fujii
Life of this patent
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Abstract
A control device for an automatic transmission of a vehicle includes a shift control section including; a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and a downshift control section configured to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state.
Claims6
A control device for an automatic transmission of a vehicle arranged
- to bring a torque converter to a lockup state and to perform a fuel cut by which a fuel supply to an engine is stopped during a coast traveling in which an accelerator pedal is released,
- to release the lockup of the torque converter when an engine speed is decreased to a lockup release rotation speed during the fuel cut, and
- to perform a fuel recovery to finish the fuel cut to restart of the fuel supply to the engine when the engine speed is decreased to be a fuel recovery rotation speed lower than the lockup release rotation speed,
- the automatic transmission including the torque converter, and a stepwise automatic shift mechanism to which a rotation from the engine is input through the torque converter, and which is arranged to attain a plurality of shift stages by combinations of engagements and disengagements of a plurality of frictional engagement elements,
- the control device comprising:
- a controller including;
- a shift control section configured to perform a downshift control of the automatic shift mechanism by a changeover of the frictional engagement elements when a vehicle speed is decreased to be equal to or smaller than a predetermined downshift vehicle speed during the fuel cut,
- the shift control section including;
- a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and
- a downshift control section configured
- to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state,
- wherein the plural stage downshift includes a continuous downshift to continuously downshift through an intermediate shift stage toward the target shift stage, and
- wherein the shift control section is configured to judge the shift based on a shift judgement vehicle speed value according to the detected vehicle speed by using a shift map in which shift lines are set, and to judge the shift by shifting the shift judgment vehicle speed to a lower speed side when the continuous downshift is performed.
10 more elements
A control method for an automatic transmission of a vehicle arranged
- to bring a torque converter to a lockup state and to perform a fuel cut by which a fuel supply to an engine is stopped during a coast traveling in which an accelerator pedal is released,
- to release the lockup of the torque converter when an engine speed is decreased to a lockup release rotation speed during the fuel cut, and
- to perform a fuel recovery to finish the fuel cut to restart of the fuel supply to the engine when the engine speed is decreased to be a fuel recovery rotation speed lower than the lockup release rotation speed,
- the automatic transmission including the torque converter, and a stepwise automatic shift mechanism to which a rotation from the engine is input through the torque converter, and which is arranged to attain a plurality of shift stages by combinations of engagements and disengagements of a plurality of frictional engagement elements,
- the control method comprising:
- performing a downshift control of the automatic shift mechanism by a changeover of the frictional engagement elements when a vehicle speed is decreased to be equal to or smaller than a predetermined downshift vehicle speed during the fuel cut;
- a deceleration state judging section judging step of judging whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state;
- and
- a downshift controlling step of commanding a plural stage downshift to downshift from the current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging step judges the sudden deceleration state,
- wherein the plural stage downshift includes a continuous downshift to continuously downshift through an intermediate shift stage toward the target shift stage, and
- wherein the downshift control is configured to judge the shift based on a shift judgement vehicle speed value according to the detected vehicle speed by using a shift map in which shift lines are set, and to judge the shift by shifting the shift judgment vehicle speed to a lower speed side when the continuous downshift is performed.
8 more elements
Dependencies are inferred from the claim text.