Automatic transmission with neutral coast down feature

• US 20070225114A1
• Filed: 03/22/2006
• Published: 09/27/2007
• Est. Priority Date: 03/22/2006
• Status: Active Grant

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: Chrysler Group LLC (Stellantis NV)
• Inventors: Cheng, Yi, Fingerman, Michael, Harkenrider, Andrew, Plunkett, Michael, Rzepecki, John, Duty, Mark
• Granted Patent: US 7,597,650 B2
• Time in Patent Office: Days
• US Class Current: 477/107
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/023 Fluid clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 2030/1809 Without torque flow between driveshaft and engine, e.g. with clutch disengaged or transmission in neutral
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/1015 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2510/1065 Transmission of zero torque
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 30/188 Controlling power parameters of the driveline, e.g. determining the required power
• CPC Class Codes: F16H 2061/0234 Adapting the ratios to special vehicle conditions
• CPC Class Codes: F16H 61/21 Providing engine brake control
• CPC Class Codes: Y02T 10/60 Other road transportation technologies with climate change mitigation effect

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. The system including a control device for determining if a negative torque condition exists and to provide an output or signal to decrease the rotational speed of said engine in response to the determination of the existence of a negative torque condition.

Claims

1. 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, the system comprising:

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 system provides an output or signal to decrease the rotational speed of said engine in response to the determination of the existence of a negative torque condition.

2. The system according to claim 1, wherein a negative torque condition is determined to exist when the rotational speed of said transmission is greater than the rotational speed of said engine.

3. The system according to claim 1, wherein said one or more clutches are selectively disengaged from said automatic transmission during the determined existence of a negative torque condition.

4. The system according to claim 1, wherein said one or more clutches are selectively pressurized to a select or predetermined pressure during the presence of the negative torque condition prior to re-engagement to said automatic transmission.

5. The system according to claim 1, further including a sensor adapted to signal or determine actuation or deactivation of an accelerator pedal.

6. The system according to claim 5, wherein deactivation of the accelerator pedal is a parameter used by the control device to determine the existence of a negative torque condition.

7. The system according to claim 1, further including a sensor for signaling or determining actuation or deactivation of a brake pedal.

8. The system according to claim 7, wherein the actuation of the brake pedal is a parameter used by the control device to determine the existence of a negative torque condition.

9. The system according to claim 1, wherein the control device is adapted to determine vehicle speed, wherein vehicle speed is a parameter used by the control device to determine the existence or absence of a negative torque condition.

10. The system according to claim 9, wherein vehicle speed is used to calculate vehicle acceleration, and wherein a rate of vehicle acceleration is a parameter used by the system to signal engagement of said one or more clutches.

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:

a control device in communication with 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 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 further wherein said clutch selectively disengages said automatic transmission, the engine controller selectively lowers the current rotational speed of said engine, or both, when the control device determines or signals the existence of a negative torque condition.

12. The system according to claim 11, wherein a negative torque condition exists when the control device determines the current rotational speed of said transmission is greater than the current rotational speed of said engine based upon signals or information provided by the engine controller and the transmission controller.

13. The system according to claim 11, further including a vehicle speed sensor in communication with the control device, wherein the speed sensor is adapted to determine or signal the current vehicle speed, including when the vehicle is experiencing a neutral coast condition.

14. The system according to claim 11, further including an accelerator pedal sensor in communication with the engine controller,

wherein the accelerator pedal sensor is adapted to signal or determine a position or degree of depression of an accelerator pedal;

the control device is adapted to determine the existence or absence of a neutral coast condition based, in part, upon parameters received from the accelerator pedal sensor; and

said clutch is selectively engaged or disengaged based upon the neutral coast condition.

15. The system according to claim 11, further including a brake pedal sensor in communication with the control device,

wherein the brake pedal sensor is adapted to signal or determine a position or degree of depression of a brake pedal;

the control device is adapted to determine the existence or absence of a neutral coast condition based upon parameters received from the brake pedal sensor; and

said clutch is selectively engaged or disengaged based upon the existence of a neutral coast condition.

16. The system according to claim 11, wherein said clutch is selectively pressurized to a select or predetermined pressure during the existence of a negative torque condition prior to re-engagement to the automatic transmission.

17. A method of controlling the engagement and disengagement of one or more clutches for a powertrain system of a vehicle comprising:

determining the existence or absence of a negative torque condition;

releasing one or more clutches if a negative torque condition is determined to exist; and

providing a select or predetermined amount of pressure to one or more clutches during the existence of a negative torque condition and prior to engagement of one or more clutches.

18. The method according to claim 17, further including the sending of a signal from an engine controller to lower a rotational speed of an engine after the releasing of one or more clutches.

19. The method according to claim 17, wherein said powertrain system includes an engine and an automatic transmission operatively connected by said one or more clutches, and wherein a negative torque condition exists when a current rotational speed of said automatic transmission is higher than a current rotational speed of said engine.

20. The method according to claim 17, further including an electronic throttle control for signaling or providing the position or degree of opening of an engine throttle and a vehicle speed sensor for signaling or providing the vehicle speed,

wherein the appropriate clutch is selected based upon signals or input provided by the electronic throttle control and the vehicle speed sensor.

21. The method according to claim 17, further including applying pressure to engage an appropriate clutch when the rate of acceleration exceeds a select or predetermined amount.