Method for operating a drive train
First Claim
1. A method of operating a motor vehicle drive train having a hybrid drive comprising an internal combustion engine, an electric motor, and an automatic transmission with a clutch arranged between the internal combustion engine and the electric motor, and one of another clutch and a torque converter located, along the drive train, between the electric motor and the automatic transmission, whereby when the drive train is powered exclusively by the electric motor, the internal combustion engine is started by engagement of the clutch arranged between the internal combustion engine and the electric motor,the method comprising the steps of:
- during a downshift, engaging the clutch arranged between the internal combustion engine and the electric motor of the hybrid drive to start the internal combustion engine, andgenerating a positive drive torque with the internal combustion engine before a rotational speed of the internal combustion engine equals a rotational speed of the automatic transmission input.
1 Assignment
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Accused Products
Abstract
A method of operating a motor vehicle drive train having a hybrid drive including an internal combustion engine, an electric motor and an automatic transmission. A clutch is located between the internal combustion engine and the electric motor, and a clutch or a torque converter is located between the electric motor and the automatic transmission such that, when the drive train is powered exclusively by the electric motor, the internal combustion engine can be started by engagement of the clutch located between the internal combustion engine and the electric motor. The clutch, arranged between the internal combustion engine and the electric motor, is engaged during the process of downshifting when the internal combustion engine is started.
34 Citations
15 Claims
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1. A method of operating a motor vehicle drive train having a hybrid drive comprising an internal combustion engine, an electric motor, and an automatic transmission with a clutch arranged between the internal combustion engine and the electric motor, and one of another clutch and a torque converter located, along the drive train, between the electric motor and the automatic transmission, whereby when the drive train is powered exclusively by the electric motor, the internal combustion engine is started by engagement of the clutch arranged between the internal combustion engine and the electric motor,
the method comprising the steps of: -
during a downshift, engaging the clutch arranged between the internal combustion engine and the electric motor of the hybrid drive to start the internal combustion engine, and generating a positive drive torque with the internal combustion engine before a rotational speed of the internal combustion engine equals a rotational speed of the automatic transmission input. - View Dependent Claims (2, 3, 6, 7, 8)
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4. A method of operating a motor vehicle drive train having a hybrid drive comprising an internal combustion engine, an electric motor, and an automatic transmission with a clutch arranged between the internal combustion engine and the electric motor, and one of another clutch and a torque converter located, along the drive train, between the electric motor and the automatic transmission, whereby when the drive train is powered exclusively by the electric motor, the internal combustion engine is started by engagement of the clutch arranged between the internal combustion engine and the electric motor,
the method comprising the steps of: -
during a downshift, engaging the clutch arranged between the internal combustion engine and the electric motor of the hybrid drive to start the internal combustion engine, starting the internal combustion engine, during the downshift, such that the internal combustion engine generates a positive drive torque before completion of the downshift and before a rotational speed of the internal combustion engine equals a rotational speed of the automatic transmission input. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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5. A method of operating a motor vehicle drive train having a hybrid drive comprising an internal combustion engine, an electric motor, and an automatic transmission with a clutch arranged between the internal combustion engine and the electric motor, and one of another clutch and a torque converter located, along the drive train, between the electric motor and the automatic transmission, whereby when the drive train is powered exclusively by the electric motor, the internal combustion engine is started by engagement of the clutch arranged between the internal combustion engine and the electric motor,
the method comprising the steps of: -
during a downshift, engaging the clutch arranged between the internal combustion engine and the electric motor of the hybrid drive to start the internal combustion engine, starting the internal combustion engine during the downshift such that, while the internal combustion engine is coasting, a pressure of at least one of a shifting component of the automatic transmission, to be engaged during the downshift and a shifting component to be disengaged during the downshift, is maintained substantially constant.
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Specification