Vehicle control method

• US 6,926,639 B2
• Filed: 08/06/2003
• Issued: 08/09/2005
• Est. Priority Date: 07/02/2003
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Hopper, Mark L.
• Primary Examiner(s): Pang, Roger
• Application Number:
  US10/635,304
• Publication Number:
  US 20050003930A1
• Time in Patent Office: 734 Days
• Field of Search: 477/3, 477/107, 477/110, 477/113, 477/127, 477/156
• US Class Current: 477/110
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/18027 Drive off, accelerating from standstill
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F02N 11/0818 Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• CPC Class Codes: F16H 2312/14 Going to, or coming from standby operation, e.g. for engine start-stop operation at traffic lights
• CPC Class Codes: F16H 61/0021 Generation or control of line pressure
• CPC Class Codes: F16H 61/0031 using auxiliary pumps, e.g. pump driven by a different power source than the engine

Abstract

A method of controlling an engine and an automatic transmission of a vehicle to reduce noise, vibration and harshness issues during shutting off a vehicle engine to improve fuel economy. The method combines vehicle engine start/stop control with neutral idle control in the transmission.

Claims

1. A method of controlling an engine and an automatic transmission in a vehicle, the automatic transmission having an engagement element and an actuator disposed between a torque input and a torque output, the engagement element operative in engagement states to selectively transfer torque from the torque input to the torque output and wherein the actuator applies a pressure to the engagement element to control the engagement state of the engagement element, said method comprising:

sensing a vehicle stop condition;

reducing the pressure applied by the actuator to the engagement element to a neutral idle pressure in response to said vehicle stop condition;

sensing said neutral idle pressure; and

stopping the vehicle engine after sensing said neutral idle pressure.

2. The method of claim 1 wherein the engagement element is a clutch pack and the actuator is a hydraulic clutch assembly and wherein said step of sensing said neutral idle pressure further includes the step of sensing a neutral idle hydraulic pressure within the clutch assembly wherein the clutch pack is in a disengaged state in response to said neutral idle hydraulic pressure.

3. The method of claim 1 further comprising the steps of:

sensing a vehicle start condition; and

increasing the pressure applied by the actuator to the engagement element in response to said vehicle start condition.

4. The method of claim 3 wherein said step of increasing the pressure applied by the actuator further comprises the steps of:

starting the engine in response to said vehicle start condition;

increasing the pressure applied to the engagement element while starting the engine in response to said vehicle start condition; and

increasing the pressure applied to the engagement element as a function of engine throttle after the engine is started.

5. The method of claim 4 wherein the engagement element enters an engaged state as a result of increasing the pressure as a function of engine throttle.

6. The method of claim 4 wherein the engagement element enters a pre-engaged state as a result of increasing the pressure while starting the engine.

7. The method of claim 1 comprising:

sensing an engine start condition;

starting the engine in response to said engine start condition while maintaining said neutral idle pressure.

8. The method of claim 7 comprising;

sensing an engine stop condition after starting the engine in response to said engine start condition; and

stopping the engine in response to said engine stop condition while maintaining said neutral idle pressure.

9. The method of claim 7 comprising:

sensing a vehicle start condition after starting the engine in response to said engine start condition; and

increasing the pressure applied to the engagement element as a function of throttle in response to said vehicle start condition.

10. A method of controlling an engine and an automatic transmission in a vehicle, the automatic transmission having an engagement element and an actuator disposed between a torque input and a torque output, the engagement element operative in engagement states to selectively transfer torque from the torque input to the torque output and wherein the actuator applies a pressure to the engagement element to control the engagement state of the engagement element, said method comprising:

stopping the engine after the engagement element is in a disengaged state;

sensing an engine start condition after stopping the engine;

starting the engine in response to said engine start condition while maintaining the engagement element in said disengaged state; and

maintaining the engagement element in said disengaged state while the engine is running.

11. The method of claim 10 further comprising:

sensing a vehicle stop condition;

placing the engagement element in said disengaged state in response to said vehicle stop condition; and

sensing when the engagement element enters a disengaged state before stopping the engine while the engagement element is in said disengaged state.

12. The method of claim 10 further comprising:

sensing a vehicle start condition; and

placing the engagement element in an engaged state as a function of throttle in response to said vehicle start condition.

13. The method of claim 10 comprising:

sensing an engine stop condition;

stopping the engine in response to said engine stop condition;

sensing a vehicle start condition after stopping the engine;

increasing pressure applied by the actuator to the engagement element while starting the engine in response to said vehicle start condition, wherein the engagement element enters a pre-engagement state as a result of increasing pressure during starting the engine; and

increasing pressure applied by the actuator to the engagement element as a function of throttle, wherein the engagement element enters an engaged state as a result of increasing pressure as a function of throttle.

14. A method of controlling an engine and an automatic transmission in a vehicle, the automatic transmission having an engagement element and an actuator disposed between a torque input and a torque output, the engagement element operative in engagement states to selectively transfer torque from the torque input to the torque output and wherein the actuator applies a pressure to the engagement element to control the engagement state of the engagement element, said method comprising:

sensing a vehicle stop condition;

reducing the pressure applied by the actuator to the engagement element in response to said vehicle stop condition to a neutral idle pressure;

sensing said neutral idle pressure;

stopping the vehicle engine after sensing the neutral idle pressure;

sensing a vehicle start condition;

starting the engine in response to said vehicle start condition;

increasing the pressure applied to the engagement element while starting the engine in response to said vehicle start condition; and

increasing the pressure as a function of engine throttle after the engine is started.

15. The method of claim 14 comprising:

sensing an engine start condition;

starting the engine in response to said engine start condition while maintaining said neutral idle pressure.

16. The method of claim 15 comprising:

sensing an engine stop condition after starting the engine in response to said engine start condition; and

stopping the engine in response to said engine stop condition while maintaining said neutral idle pressure.