Automatic transmission with neutral coast down feature
First Claim
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1. A system for controlling engagement and disengagement of one or more clutches that are adapted to operatively connect an engine and an automatic transmission of a vehicle, the system comprising:
- a torque convener coupling an engine to an automatic transmission having one or more gear-selection clutches,a control device configured to obtain or receive a rotational speed of said engine, to obtain or receive a rotational speed of said automatic transmission, and to determine if a negative torque condition exists,wherein the control device causes selective disengagement of each one of said one or more clutches putting said automatic transmission in neutral gear in response to a determination that the negative torque condition exists.
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Abstract
A system for controlling the engagement and disengagement of one or more clutches that are adapted to operatively connect an engine and an automatic transmission includes a control device for determining if a negative torque condition exists and for providing an output or signal to decrease the rotational speed of the engine in response to the determination of the existence of the negative torque condition.
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Citations
21 Claims
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1. A system for controlling engagement and disengagement of one or more clutches that are adapted to operatively connect an engine and an automatic transmission of a vehicle, the system comprising:
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a torque convener coupling an engine to an automatic transmission having one or more gear-selection clutches, a control device configured to obtain or receive a rotational speed of said engine, to obtain or receive a rotational speed of said automatic transmission, and to determine if a negative torque condition exists, wherein the control device causes selective disengagement of each one of said one or more clutches putting said automatic transmission in neutral gear in response to a determination that the negative torque condition exists. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for controlling the engagement and disengagement of a clutch adapted to operatively connect an engine and an automatic transmission, the system comprising:
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a torque convener coupling an engine to an automatic transmission, a control device comprised of an engine controller and a transmission controller; an engine speed sensor in communication with the engine controller and adapted to provide a signal associated with a current rotational speed of said engine; and a torque converter turbine output shaft sensor in communication with the transmission controller and adapted to provide a signal associated with a current rotational speed of said transmission; wherein the control device determines whether a negative torque condition exists based upon signals Or information received from or provided by the engine controller and the transmission controller, and wherein said clutch selectively disengages said automatic transmission putting the automatic transmission into neutral gear, when the control device determines or signals the existence of the negative torque condition. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method of controlling engagement and disengagement of one or more clutches for a powertrain system of a vehicle comprising;
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(a) providing a (1) powertrain system that comprises an automatic transmission coupled by a torque convener to an engine with the automatic transmission having a plurality of gear-selection clutches, and (2) a control device monitoring operation of the engine and transmission that comprises at least one of a transmission controller and an engine controller; (b) determining whether a negative torque condition exists; (c) releasing each one of die plurality of gear-selection clutches if the negative torque condition is determined to exist, putting the automatic transmission into a neutral gear condition; (d) lowering speed of the engine while the automatic transmission is in the neutral gear condition; and (e) re-engaging at least one of the plurality of gear-selection clutches putting the automatic transmission into gear upon determining that the negative torque condition no longer exists. - View Dependent Claims (18, 19, 20, 21)
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Specification