Automatic transmission and control method therefor
AssigneeNissan Motor Co., Ltd.
InventorsDaigo Kishi, Toshiaki Motomura
Life of this patent
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Abstract
In a vehicle having a continuously variable transmission, a controller selectively performs a first control mode in which a transmission ratio is controlled in a stepless manner, and a second control mode in which the transmission ratio is controlled in a stepwise manner to perform an upshift after a vehicle speed has increased. When the second control mode is selected in response to a driver's acceleration request, the controller continuously downshifts the transmission ratio until the upshift is performed.
Claims8
A control method for controlling an automatic transmission having a first control mode in which a transmission ratio of a continuously variable transmission is controlled in a stepless manner, and a second control mode in which the transmission ratio is controlled in a stepwise manner to perform an upshift after a vehicle speed has increased, the control method comprising:
- continuously downshifting until the upshift is performed when the second control mode is selected in response to a driver's acceleration request,
- the continuous downshifting being executed during a period from when the driver's acceleration request occurs until an engine rotational speed reaches an upshift determination rotational speed.
A control method for controlling an automatic transmission having a first control mode in which a transmission ratio of a continuously variable transmission is controlled in a stepless manner, and a second control mode in which the transmission ratio is controlled in a stepwise manner to perform an upshift after a vehicle speed has increased, the control method comprising:
- continuously downshifting until the upshift is performed when the second control mode is selected in response to a driver's acceleration request;
- and
- reducing a downshift amount upon determining that a traveling state at a start of acceleration is a state in which a risk exists that a predetermined shift speed cannot be achieved as compared to when the predetermined shift speed can be achieved.
An automatic transmission comprising:
- a continuously variable transmission, and
- a controller that selects one control mode from among a first control mode in which a transmission ratio of the continuously variable transmission is controlled in a stepless manner, and a second control mode in which the transmission ratio of the continuously variable transmission is controlled in a stepwise manner to perform an upshift after the vehicle speed has increased, in accordance with a driver's acceleration request, and that controls the transmission ratio of the continuously variable transmission based on the control mode that was selected, and
- when selecting the second control mode, the controller continuously downshifts until the upshift is performed,
- the controller executing the continuous downshifting during a period from when the driver's acceleration request occurs until an engine rotational speed reaches an upshift determination rotational speed.
Dependencies are inferred from the claim text.