Electronic control for a starting clutch

• US 4,558,772 A
• Filed: 08/29/1984
• Issued: 12/17/1985
• Est. Priority Date: 08/29/1984
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Grimes, Michael R., Vukovich, William J.
• Primary Examiner(s): Staab, Lawrence J.
• Application Number:
  US06/645,338
• Time in Patent Office: 475 Days
• Field of Search: 192/0.075, 192/0.076, 192/0.084, 192/0.096, 192/103 R, 361/242
• US Class Current: 477/176
• CPC Class Codes: B60W 2050/001 Proportional integral [PI] controller
• CPC Class Codes: B60W 2050/0012 Feedforward or open loop systems
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/023 Clutch engagement rate
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: F16D 2500/10412 Transmission line of a vehicle
• CPC Class Codes: F16D 2500/1045 Friction clutch
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/50224 Drive-off
• CPC Class Codes: F16D 2500/70241 Angle
• CPC Class Codes: F16D 2500/70252 Clutch torque
• CPC Class Codes: F16D 2500/7027 Engine speed
• CPC Class Codes: F16D 2500/70605 Adaptive correction; Modifying control system parameters, e.g. gains, constants, look-up tables
• CPC Class Codes: F16D 2500/70652 Open loop
• CPC Class Codes: F16D 2500/70668 Signal filtering
• CPC Class Codes: F16D 2500/7087 of the vehicle
• CPC Class Codes: F16D 48/066 Control of fluid pressure, e.g. using an accumulator F16D48/062, F16D48/068 take precedence

Abstract

An electronic control for energizing an electrically operated valve of a motor vehicle starting clutch at a level which compensates for performance variations of the valve and/or clutch so that the desired clutch engagement feel may be repeatably produced. The compensated energization level is formed by the combination of a principal term determined as a function of engine speed and a corrective, or vernier, term determined as a function of engine speed deviation from a reference engine speed. The reference engine speed is obtained by determining the desired steady state engine speed for the clutch engagement and applying thereto a time response characteristic that generally resembles that of the vehicle engine.

Claims

1. For a motor vehicle including a fluid-operated clutch for transmitting torque from the engine to the transmission wherein the speed of the engine during engagement of the clutch for a given setting of the engine throttle is determined by the torque capacity of the clutch which in turn is determined by the energization duty cycle of an electrically operated actuator, the combination comprising:

principal clutch control means responsive to the speed of the engine for defining a principal energization duty cycle value as a function of engine speed; and

vernier clutch control means responsive to the difference between the actual engine speed and a reference engine speed for developing a vernier energization duty cycle value which is combined with the principal energization duty cycle value and applied to said actuator thereby to compensate the applied duty cycle value for variations in the actual engine speed due to performance variations in the actuator and other components of the system, the vernier clutch control means including means for integrating the difference between the actual engine speed and the reference engine speed to form the vernier duty cycle value thereby to minimize the steady state value of such difference, means responsive to the engine throttle setting to define a steady state reference engine speed value at which it is desired to maintain the actual engine speed relatively constant during engagement of said clutch, and means responsive to changes in the steady state reference engine speed value during engagement of the clutch to effect the required changes in value as a function of time in accordance with a dynamic response characteristic that generally approximates the dynamic response characteristic of the engine thereby to stabilize the engine speed response during engagement of the clutch.

2. For a motor vehicle including a fluid-operated clutch for transmitting engine output torque to the vehicle drivetrain and an electrically operated interface element energizable at a variable duty cycle for regulating the torque capacity of the clutch, a control system for operating the interface element comprising:

principal control means including duty cycle look-up means responsive to the engine speed for supplying a principal duty cycle value for said interface element such that the torque capacity of the clutch is progressively increased with increasing engine speed to a value substantially equal to the engine output torque whereafter the engine speed is maintained substantially constant at a steady state value for the remainder of the clutch engagement;

vernier control means including engine speed look-up means responsive to the engine throttle setting for supplying a reference steady state speed value at which it is desired to maintain the engine speed substantially constant during clutch engagement, means responsive to changes in the reference steady state speed value during clutch engagement to form a dynamic engine speed reference signal by applying a time response characteristic to such changes which generally approximates the time response characteristic of the engine, and means for integrating the difference between the dynamic engine speed reference signal and the actual engine speed with respect to time to form a vernier duty cycle value; and

means for combining the principal duty cycle value with the vernier duty cycle value and energizing the interface element in accordance therewith so as to adaptively compensate the energization duty cycle for performance variations in the interface element and clutch whereby the engine speed during clutch engagement is repeatably controlled regardless of such performance variations.

3. For a motor vehicle including a fluid-operated clutch for transmitting engine output torque to the vehicle drivetrain wherein the speed of the engine during engagement of the clutch for a given setting of the engine throttle is determined by the torque capacity of the clutch which in turn is determined by the energization duty cycle of an electrically operated actuator, the combination comprising:

means effective during engagement of said clutch for energizing the actuator according to the combination of a principal duty cycle value and a vernier duty cycle value, the principal duty cycle value being determined as a function of engine speed such that the engine speed is progressively increased to a steady state value and thereafter maintained at such value for the remainder of the clutch engagement and the vernier duty cycle value being determined as a function of the integral with respect to time of the difference between the actual engine speed and a reference engine speed having imposed thereon a dynamic time response characteristic that generally approximates the dynamic time response characteristic of the engine; and

means effective following engagement of said clutch for energizing the actuator in accordance with a further duty cycle value determined as a function of engine speed such that the torque capacity of the clutch is maintained in excess of the engine output torque thereby to maintain the clutch engagement.