Shift control apparartus and shift control method of automatic transmission of vehicle
First Claim
1. A shift control apparatus that executes a shift control of an automatic transmission that changes a speed of a rotation transferred from a power source to an input member and outputs the rotation to a drive wheel, wherein, in response to a downshift determination made during an upshift operation which engages a first friction coupling device, the shift control apparatus performs a downshift operation which disengages the first friction coupling device and engages a second friction coupling device, the shift control apparatus comprising:
- a multiple shift execution unit that starts the downshift operation in response to the downshift determination; and
a torque reduction control execution unit that;
determines, after starting the downshift operation, whether a rotational speed of the input member has increased to be equal to or higher than a control start-up rotational speed that is preliminarily set to be lower than a synchronous rotational speed, which is determined in accordance with a shift ratio of a gear stage to be established by the downshift operation; and
executes a torque reduction control that reduces a torque output of the power source when the rotational speed of the input member increases to be equal to or higher than the control start-up rotational speed.
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Accused Products
Abstract
The invention relates to a shift control apparatus for an automatic transmission that executes a torque reduction control when the transmission downshifts in response to a downshift determination made during an upshift. The shift control apparatus includes a multiple shift execution unit that starts the downshift in response to the downshift determination, and a torque reduction control execution unit that determines whether the rotational speed of the input member is at least a control start-up rotational speed, after the downshift operation starts, and executes a torque reduction control of the power source when the rotational speed of the input member is increased to at least the control start-up rotational speed. This allows the rotational speed of the input shaft to be quickly changed to the appropriate synchronous rotational speed. Thus, the desired driving force is provided upon completion of the downshift without overspeeding the engine.
49 Citations
16 Claims
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1. A shift control apparatus that executes a shift control of an automatic transmission that changes a speed of a rotation transferred from a power source to an input member and outputs the rotation to a drive wheel, wherein, in response to a downshift determination made during an upshift operation which engages a first friction coupling device, the shift control apparatus performs a downshift operation which disengages the first friction coupling device and engages a second friction coupling device, the shift control apparatus comprising:
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a multiple shift execution unit that starts the downshift operation in response to the downshift determination; and
a torque reduction control execution unit that;
determines, after starting the downshift operation, whether a rotational speed of the input member has increased to be equal to or higher than a control start-up rotational speed that is preliminarily set to be lower than a synchronous rotational speed, which is determined in accordance with a shift ratio of a gear stage to be established by the downshift operation; and
executes a torque reduction control that reduces a torque output of the power source when the rotational speed of the input member increases to be equal to or higher than the control start-up rotational speed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of controlling an automatic transmission, which changes a speed of a rotation transferred from a power source to an input member and outputs the rotation to a drive wheel, wherein, in response to a downshift determination made during an upshift operation that engages a first friction coupling device, a downshift operation, which disengages the first friction coupling device and engages a second friction coupling device, is performed;
- the method comprising;
starting the downshift operation in response to the downshift determination;
determining, after starting the downshift operation, whether a rotational speed of an input member has increased to be equal to or higher than a control start-up rotational speed that is preliminarily set to be lower than a synchronous rotational speed, which is determined in accordance with a shift ratio of a gear stage to be established by the downshift operation; and
executing a torque reduction control to reduce a torque output of the power source when the rotational speed of the input member increases to be equal to or higher than the control start-up rotational speed. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
- the method comprising;
Specification