Method for shifting a twin-clutch transmission and twin-clutch transmission arrangement
First Claim
1. A method for shifting a twin-clutch transmission having first and second transmission input shafts and a transmission output shaft, the input shafts having associated first and second clutches, respectively, in which the first clutch initially transmits engine torque in a state of static friction and the second clutch is initially open, comprising;
- bringing the second transmission shaft to a synchronous speed with a selected gear to be engaged and engaging the selected gear;
opening the first clutch in a regulated manner using a slip controller so that, at a desired speed of the engine side of the first clutch, the clutch operates at a slip limit,closing the second clutch in a controlled manner until the first clutch, which is being operated at the slip limit by the slip controller, no longer transmits any torque,fully opening the first clutch so that the second clutch transmits the engine power by itself; and
disengaging the initial gear essentially without loss of torque;
wherein the speed of the second transmission input shaft is changed with the aid of a synchronizer to the appropriate synchronous speed; and
wherein the synchronizer takes torque required to accelerate the second transmission input shaft from the transmission output shaft.
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Accused Products
Abstract
A twin-clutch transmission has first and second transmission input shafts and a transmission output shaft, each input shaft having an associated friction clutch. In the initial state, the first clutch transmits engine torque in a state of static friction and the second clutch is open. In a shifting operation the second transmission input shaft is brought to a synchronous speed, thus permitting the engagement of a selected gear. In order to prevent a condition in which both clutches are in static friction engagement, which would result in locking up of the transmission, the speed of at least one clutch is maintained in the range of sliding friction to a value in the vicinity of the synchronization speed until the torque to be transmitted has been transferred steadily from the first clutch to the second clutch. A synchronizer is used when shifting up in the overrun condition.
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Citations
25 Claims
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1. A method for shifting a twin-clutch transmission having first and second transmission input shafts and a transmission output shaft, the input shafts having associated first and second clutches, respectively, in which the first clutch initially transmits engine torque in a state of static friction and the second clutch is initially open, comprising;
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bringing the second transmission shaft to a synchronous speed with a selected gear to be engaged and engaging the selected gear; opening the first clutch in a regulated manner using a slip controller so that, at a desired speed of the engine side of the first clutch, the clutch operates at a slip limit, closing the second clutch in a controlled manner until the first clutch, which is being operated at the slip limit by the slip controller, no longer transmits any torque, fully opening the first clutch so that the second clutch transmits the engine power by itself; and disengaging the initial gear essentially without loss of torque; wherein the speed of the second transmission input shaft is changed with the aid of a synchronizer to the appropriate synchronous speed; and wherein the synchronizer takes torque required to accelerate the second transmission input shaft from the transmission output shaft. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 15, 17)
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2. A method for shifting a twin-clutch transmission having first and second transmission input shafts and a transmission output shaft, the input shafts having associates first and second friction clutches, respectively, in which the first clutch initially transmits engine torque in a state of static friction and the second clutch is initially open comprising:
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bringing the second transmission shaft to a synchronous speed with a selected gear to be engaged and engaging the selected gear; closing the second clutch in a regulated manner using a slip controller so that, at a desired speed of the engine-side of the second clutch, the second clutch operates at a slip limit, opening the first clutch in a controlled manner until the second clutch, which is being operated at the slip limit by the slip controller, transmits the full torque from the engine; fully closing the second clutch, so that the second clutch transmits the engine power by itself; and when the first clutch is fully open, disengaging the initial gear essentially without torque; wherein the speed of the second transmission input shaft is changed with the aid of a synchronizer to the appropriate synchronous speed; and wherein the synchronizer takes torque required to accelerate the second transmission input shaft from the transmission output shaft. - View Dependent Claims (10, 11, 12, 13, 14, 16)
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- 18. A twin-clutch transmission comprising a first transmission input shaft carrying an initially engaged gear, a second transmission input shaft carrying a selected gear to be engaged after shifting, a transmission output shaft and a synchronizer providing a torque transmitting coupling between the second transmission input shaft and the transmission output shaft for the purpose of synchronization.
Specification