Automatic transmission with neutral coast down feature

• US 7,597,650 B2
• Filed: 03/22/2006
• Issued: 10/06/2009
• 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 E., Harkenrider, Andrew J., Rzepecki, John M. II, Plunkett, Michael L., Duty, Mark J.
• Primary Examiner(s): Le; David D.
• Application Number:
  US11/386,913
• Publication Number:
  US 20070225114A1
• Time in Patent Office: 1,294 Days
• Field of Search: 477/107, 477/110, 477/118, 477/119, 477/169, 477/171, 477/173, 477/174, 477/175, 477/176, 477/184, 477/185, 477/901, 477/904
• US Class Current: 477/110
• 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 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.

Claims

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.

2. The system according to claim 1, wherein the 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 the control device is further configured to determine if the negative torque condition no longer exists and wherein said one or more clutches are selectively re-engaged putting said transmission into gear in response to a determination that the negative torque condition no longer exists.

4. The system according to claim 3, 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 an actuation of an accelerator pedal or a deactivation of the accelerator pedal.

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

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

10. The system according to claim 9. wherein the vehicle speed is used to calculate a vehicle acceleration, and wherein the 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 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.

12. The system according to claim 11, wherein the 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 die speed sensor is adapted to determine or signal a 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 the 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 the negative torque condition prior to re-engagement to the automatic transmission and said clutch is re-engaged putting the automatic transmission into gear when the negative torque condition no longer exists.

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

(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.

18. The method according to claim 17, wherein the control device comprises an engine controller and step (d) comprises sending of a signal from the engine controller to lower the speed of the engine.

19. The method according to claim 17, wherein the negative torque condition exists when a current rotational speed of said automatic transmission is higher than a current rotational speed of said engine, and wherein the releasing each one of the plurality of gear-selection clutches if the negative torque condition is determined to exist in step (c) causes each engaged gear-selection clutch to disengage from said automatic transmission putting said automatic transmission into neutral gear.

20. The method according to claim 17, farther including an electronic throttle control for signaling or providing a position or degree of opening of an engine throttle and a vehicle speed sensor for signaling or providing a vehicle speed, wherein an appropriate one or more of the clutches is selected and released in step (c) based upon signals or input provided by the electronic throttle control and the vehicle speed sensor.

21. The method according to claim 17, wherein before step (e), comprising the further step of applying a select or predetermined amount of pressure to an appropriate one of the gear-selection clutches during the existence of the negative torque condition and comprising during step (e) applying pressure to re-engage at least one of the plurality of gear-selection clutches when a rate of acceleration of the vehicle exceeds a select or predetermined amount putting the automatic transmission of the powertrain system into gear.