Honda Giken Kogyo Kabushiki Kaisha

Yoshiyuki Ura

Takamichi Shimada

Shuichi Fujimoto

Hisashi Kunii

Kazumi Sato

Noboru Sekine

An automatic transmission includes a frictionally engaging element for establishing a predetermined speed range. This predetermined speed range may be a second or higher speed range, and it is set temporarily in N-D squat control and also used for establishing a reverse range. In this transmission, engagement-actuation control of the frictionally engaging element for establishing the predetermined speed range which is executed when a shift is made from a N range to a R range comprises a plurality of control stages. When a shift to the R range is made via the N range following a N-D shift, a shift control apparatus detects the engagement condition of the the frictionally engaging element for establishing the predetermined speed range, selects one of the control stages in correspondence with the engagement condition, and initiates the engagement-actuation control of the frictionally engaging element from the control stage selected, so as to execute an engagement control for establishing the reverse range. Thus, in-gear shifts are executed smoothly without any delay in a N-D-N-R range shift.

Shift control apparatus for automatic transmission

An engagement-actuation control for a frictionally engaging element to establish a driving range in response to a shift command to shift from a neutral range to the driving range comprises a plurality of control stages including an invalid-stroke-clearing control. This invalid-stroke-clearing control is finished when invalid-stroke clearing is judged complete on the basis that the absolute value of the rate of rotational change of a turbine shaft is equal to or greater than a predetermined rate and that the difference between the rotational speed of an engine and the rotational speed of the turbine shaft is equal to or greater than a predetermined value.

A shift control apparatus for an automatic transmission for a vehicle wherein D-N-D in-gear shifts are carried out quickly without any shift shock. Engagement-actuation control for a frictionally engaging element to establish a D range when a shift is made from a N range to the D range comprises a plurality of control stages, for example, an invalid-stroke clearing stage, an intermediate-pressure retaining stage, a feedback stage, etc. When the shift to the D range is made following a shift from the D range to the N range, a shift control apparatus detects the engagement condition of the the frictionally engaging element for establishing the D range, selects one of the control stages in correspondence with the engagement condition, and initiates the engagement-actuation control for the frictionally engaging element from the control stage selected.

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Niiza, Japan

Yoshiyuki Ura