Clutch control method for determining clutch kiss-point during running conditions

• US 6,086,514 A
• Filed: 08/12/1998
• Issued: 07/11/2000
• Est. Priority Date: 12/20/1996
• Status: Expired due to Fees

• Current Assignee: Luk Leamington Limited (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Luk Leamington Limited (INA-Holding Schaeffler GmbH & Co. KG)
• Inventors: Jones, Charles John, Martin, Paul Grahame
• Primary Examiner(s): TA, KHOI QUANG
• Application Number:
  US09/117,855
• Time in Patent Office: 699 Days
• Field of Search: 477/84, 477/86, 477/174, 477/175, 477/180
• US Class Current: 477/180
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2510/0225 Clutch actuator position
• CPC Class Codes: B60W 2510/0291 Clutch temperature
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16D 2500/10412 Transmission line of a vehicle
• CPC Class Codes: F16D 2500/3026 Stroke
• CPC Class Codes: F16D 2500/30404 Clutch temperature
• CPC Class Codes: F16D 2500/30426 Speed of the output shaft
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/50236 Adaptations of the clutch characteristics, e.g. curve clutch capacity torque - clutch actuator displacement
• CPC Class Codes: F16D 2500/50245 Calibration or recalibration of the clutch touch-point
• CPC Class Codes: F16D 2500/50251 During operation
• CPC Class Codes: F16D 2500/7041 Position
• CPC Class Codes: F16D 2500/70605 Adaptive correction; Modifying control system parameters, e.g. gains, constants, look-up tables
• CPC Class Codes: F16D 48/066 : Control of fluid pressure, e.g. using an accumulator F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 63/46 : Signals to a clutch outside the gearbox

Abstract

A method of determining, during a clutch re-engagement process, the kiss-point of a vehicle clutch (14) having a driven plate (40) which drives a vehicle from an engine (10) via a multi-ratio transmission (12). The clutch is operated via a clutch actuating mechanism (20, 22) under the control of an electronic control means (36) using a method comprising the steps of: checking that the throttle (18) of the engine is closed and that the vehicle is in an engine overrun condition; partially reengaging the clutch (14) up to a point (Y) where the clutch increases the engine speed to a substantially constant level below the speed of the driven plate (40) of the clutch; measuring (34) the position of the clutch actuating mechanism (20, 22) when in said partially engaged condition; computing from said position measurement(s) and the known engagement/torque characteristics (T1, T2, T3) of the clutch the current kiss-point position (T); saving said current kiss-point position (T), and completing the engagement of the clutch.

Claims

1. A method of determining, during a clutch re-engagement process, the kiss-point of a vehicle clutch having a driven plate which drives a vehicle from an engine via a multi-ratio transmission, operation of the clutch being via a clutch actuating mechanism under the control of an electronic control means, said method comprising the steps of:

checking that the throttle of the engine is closed and that the vehicle is in an engine overrun condition;

partially re-engaging the clutch up to a point where the clutch increases the engine speed to a substantially constant level below the speed of the driven plate of the clutch;

measuring the position of the clutch actuating mechanism when in said partially engaged condition;

computing from said position measurement and the known engagement/torque characteristics of the clutch the current kiss-point position;

saving said current kiss-point position, and

completing the engagement of the clutch.

2. A method according to claim 1 in which the electronic control means senses the engine speed and the speed of the driven plate of the clutch prior to re-engagement and then re-engages the clutch to drive the engine at a speed in a predetermined relationship to said sensed speeds.

3. A method according to claims 1 in which the engine is driven at a speed halfway between the sensed engine and driven plate speeds.

4. A method according to claim 1 in which during a given kiss-point determination a series of clutch actuating mechanism position measurements are made and said series of measurements are compared for consistency and if sufficiently consistent, indicating a steady state clutch engagement condition, are utilised for a kiss-point determination.

5. A method according to claim 4 in which a time limit is set by the electronic control means for making the position measurements of the clutch actuating mechanism to prevent prolonged clutch slippage.

6. A method according to claim 1 in which a given kiss-point determination is aborted if the throttle does not remain closed or if the driven plate speed does not remain above a lower limit or if the temperature of the clutch, exceeds a predetermined level.

7. A method according to claim 1 which includes the preliminary step of checking that the engine has been operating for a sufficient time to ensure that normal clutch operating temperature has been reached.

8. A method according to claims 7 in which immediately prior to each deactivation of the electronic control means at the end of each vehicle journey the control means stores a value of kiss-point position related to the final actual kiss-point position computed during that specific journey.

9. A method according to claim 8 in which stored value of kiss-point position at the end of each vehicle journey is equal to the average of all the kiss-point positions computed during that specific journey.

10. A clutch control system which includes an electronic control means a routine for determining the kiss-point of the associated clutch in accordance with the method of claim 1.

11. A method of determining the kiss-point of a vehicle clutch having a driven plate which drives a vehicle from an engine via a multi-ratio transmission, operation of the clutch being via a clutch actuating mechanism under the control of an electronic control means, said method comprising the steps of:

determining when a downshift in the operative ratio of the associated transmission has been selected;

checking that the throttle is closed;

disengaging the clutch;

disengaging the old transmission ratio and engaging the required new ratio;

Partially re-engaging the clutch up to a point where the clutch increases the engine speed to a substantially constant level below the speed of the driven plate of the clutch;

measuring the position of the clutch actuating mechanism when in said partially engaged condition;

computing from said position measurement and the known engagement/torque characteristics of the clutch the current kiss-point position;

saving said current kiss-point position, and

completing the engagement of the clutch.