CONVERTERLESS TRANSMISSION SHIFT CONTROL SYSTEM
First Claim
1. A control method for controlling speed ratio shifts in a multiple-ratio converterless transmission for an automotive vehicle powertrain wherein an internal combustion engine is connected directly to torque input elements of the transmission, the transmission having multiple pressure-actuated friction elements, a speed ratio change in the transmission being effected by engaging a pressure actuator for an oncoming friction element and releasing a pressure actuator for an off-going friction element, the method comprising the steps of:
- increasing actuating pressure for an oncoming friction element during a torque phase of a power-on upshift;
detecting slip speed of an actuator for an oncoming friction element at the beginning of an inertia phase of a power-on upshift;
controlling slip speed of the oncoming friction element using closed loop control triggered by detection of slip speed of the actuator for the oncoming friction element; and
increasing pressure of the actuator for the oncoming friction element at the end of the closed loop control as slip of the oncoming friction element becomes approximately zero.
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Accused Products
Abstract
A converterless, multiple-ratio transmission and shift control method wherein smoothness of power-on upshifts and downshifts and power-off upshifts and downshifts is achieved by closed loop control of slip speed and friction element actuating pressure for an oncoming friction element, the data used during the closed loop control including speed sensor information for multiple friction elements during upshift and downshifts events.
42 Citations
16 Claims
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1. A control method for controlling speed ratio shifts in a multiple-ratio converterless transmission for an automotive vehicle powertrain wherein an internal combustion engine is connected directly to torque input elements of the transmission, the transmission having multiple pressure-actuated friction elements, a speed ratio change in the transmission being effected by engaging a pressure actuator for an oncoming friction element and releasing a pressure actuator for an off-going friction element, the method comprising the steps of:
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increasing actuating pressure for an oncoming friction element during a torque phase of a power-on upshift;
detecting slip speed of an actuator for an oncoming friction element at the beginning of an inertia phase of a power-on upshift;
controlling slip speed of the oncoming friction element using closed loop control triggered by detection of slip speed of the actuator for the oncoming friction element; and
increasing pressure of the actuator for the oncoming friction element at the end of the closed loop control as slip of the oncoming friction element becomes approximately zero. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A control method for controlling speed ratio shifts in a multiple-ratio converterless transmission for an automotive vehicle powertrain wherein an internal combustion engine is connected directly to torque input elements of the transmission, the transmission having multiple pressure-actuated friction elements, a speed ratio change in the transmission being effected by engaging a pressure actuator for an oncoming friction element and releasing a pressure actuator for an off-going friction element, the method comprising the steps of:
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controlling power-on downshifts by detecting slip speed of the off-going friction element;
controlling slip speed of the oncoming friction element during an inertia phase, the inertia phase being triggered by detection of slip speed of the off-going friction element; and
increasing pressure on the actuator for the oncoming friction element upon completion of the inertia phase. - View Dependent Claims (8, 9, 10)
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11. A control method for controlling speed ratio shifts in a multiple-ratio converterless transmission for an automotive vehicle powertrain wherein an internal combustion engine is connected directly to torque input elements of the transmission, the transmission having multiple pressure-actuated friction elements, a speed ratio change in the transmission being effected by engaging a pressure actuator for an oncoming friction element and releasing a pressure actuator for an off-going friction element, the method comprising the steps of:
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controlling power-off upshifts by measuring slip speed of the oncoming friction element to directly sense torque capacity of the oncoming friction element; and
controlling oncoming friction element capacity with closed loop control of pressure on the actuator for the oncoming friction element during a power-off upshift.
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12. A control method for controlling speed ratio shifts in a multiple-ratio converterless transmission for an automotive vehicle powertrain wherein an internal combustion engine is connected directly to torque input elements of the transmission, the transmission having multiple pressure-actuated friction elements, a speed ratio change in the transmission being effected by engaging a pressure actuator for an oncoming friction element and releasing a pressure actuator for an off-going friction element, the method comprising the steps of:
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controlling a power-off downshift by measuring slip speed of the off-going friction element thereby sensing loss of capacity of the off-going friction element;
determining off-going friction element slip speed to detect loss of capacity of the actuator for the off-going friction element; and
controlling slip speed of the oncoming friction element during closed loop control of pressure of the actuator for the oncoming friction element.
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13. A vehicle powertrain including a multiple-ratio converterless transmission with multiple-ratio gearing for an automotive vehicle powertrain wherein an internal combustion engine is connected directly to torque input elements of the transmission gearing;
- the transmission comprising;
multiple pressure actuated friction elements for controlling relative speeds of gear elements of the gearing, a speed ratio change in the transmission being effected by engaging a pressure actuator for an oncoming friction element and releasing a pressure actuator for an off-going friction element during an upshift;
at least two speed sensors for independently measuring speed of separate ones of the gear elements; and
an electronic controller for increasing actuating pressure for an oncoming friction element during a torque phase of the upshift;
the speed sensors being characterized by separate speed signals for the electronic controller, whereby the electronic controller detects slip speed for an oncoming friction element during an inertia phase of the upshift and controls slip speed of the oncoming friction element in response to the speed signals for the speed sensors. - View Dependent Claims (15)
- the transmission comprising;
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14. A vehicle powertrain including a multiple-ratio converterless transmission with multiple-ratio gearing for an automotive vehicle powertrain wherein an internal combustion engine is connected directly to torque input elements of the transmission gearing;
- the transmission comprising;
multiple pressure actuated friction elements for controlling relative speeds of gear elements of the gearing, a speed ratio change in the transmission being effected by engaging a pressure actuator for an oncoming friction element and releasing a pressure actuator for an off-going friction element during a downshift;
at least two speed sensors for independently measuring speed of separate ones of the gear elements; and
an electronic controller for increasing actuating pressure for an oncoming friction element during a torque phase of the downshift;
the speed sensors being characterized by separate speed signals for the electronic controller, whereby the electronic controller detects slip speed for an off-going friction element during an inertia phase of the downshift and controls slip speed of the oncoming friction element in response to the speed signals for the speed sensors. - View Dependent Claims (16)
- the transmission comprising;
Specification