Control system for a clutch for a motor vehicle

• US 4,905,801 A
• Filed: 05/13/1988
• Issued: 03/06/1990
• Est. Priority Date: 05/20/1987
• Status: Expired due to Fees

• Current Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Tezuka, Kazunari
• Primary Examiner(s): Bonck, Rodney H.
• Application Number:
  US07/193,893
• Time in Patent Office: 662 Days
• Field of Search: 192/0.032, 192/0.076, 192/21.5, 364/424.1
• US Class Current: 477/87
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• 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 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 10/107 with endless flexible members
• CPC Class Codes: B60W 2510/0241 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 2510/0604 Throttle position
• 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 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16D 2500/1022 Electromagnet
• CPC Class Codes: F16D 2500/10412 Transmission line of a vehicle
• CPC Class Codes: F16D 2500/10475 Magnetic field, e.g. electro-rheological, magnetisable particles
• CPC Class Codes: F16D 2500/1088 CVT
• 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 2500/31466 Gear lever
• CPC Class Codes: F16D 2500/70252 Clutch torque
• CPC Class Codes: F16D 2500/7027 Engine speed
• CPC Class Codes: F16D 2500/7044 Output shaft torque
• CPC Class Codes: F16D 2500/70605 : Adaptive correction; Modifying control system parameters, e.g. gains, constants, look-up tables
• CPC Class Codes: F16D 48/064 : Control of electrically or electromagnetically actuated clutches F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 61/66 : specially adapted for continuously variable gearings control of exclusively fluid gearing F16H61/38

Abstract

A control system for an electromagnetic clutch for a vehicle has an engine speed sensor, a clutch driven member speed sensor and a throttle position sensor. The system has a memory storing first torque capacities increasing with increase of engine speed and storing second torque capacities at clutch engagement rate 100% in accordance with engine speed and throttle position. The actual clutch engagement rate is calculated based on output signals of the engine speed sensor and the clutch driven member speed sensor. A first torque capacity and a second capacity are derived from the memory in accordance with output signals of the sensors. A torque capacity Tc for engaging the clutch is calculated as follows,

Tc=Re·TcL+(1-Re)·Tcs

where Re is the clutch engagement rate, Tcs is the first torque capacity and TcL is the second torque capacity.

Claims

1. A control system for a clutch for a vehicle driven by an engine having an engine speed sensor, a clutch driven member speed sensor and a throttle position sensor, the system comprising:

a memory storing first torque capacities increasing with increase of engine speed and storing second torque capacities dependent on engine torque characteristic in accordance with engine speed and throttle position;

means responsive to output signals of the engine sensor and the clutch driven member speed sensor for producing an actual clutch engagement rate signal;

deriving means responsive to output signals of said engine speed and throttle position sensors for deriving a first torque capacity and a second torque capacity from the memory;

means responsive to the clutch engagement rate signal and the derived first and second torque capacities for calculating a calculated torque capacity by using a predetermined equation;

actuating means for engaging the clutch depending on the calculated torque capacity.

2. The system according to claim 1 wherein the predetermined equation for calculating the torque capacity Tc is

3. The control system according to claim 1, wherein

said clutch is an electromagnetic clutch.

4. The control system according to claim 3, wherein

said electromagnetic clutch is an electromagnetic powder clutch.

5. A control system for a clutch connected between an engine and driving wheels of a motor vehicle having an engine speed sensor to detect rotating speed of an output shaft of said engine for providing an engine speed signal, a first sensor to detect speed corresponding to rotating speed of a driven member of said clutch for producing a driven member speed signal, and a throttle position sensor to detect opening degree of a throttle valve mounted on said engine, the improvement in the control system comprising:

first storing means for providing a first clutch torque characteristic with respect to said engine speed signal when said clutch is completely disengaged;

second storing means for providing a second clutch torque characteristic with respect to said engine speed signal and said opening degree of said throttle valve when said clutch is fully engaged;

clutch engagement rate setting means responsive to said engine speed and said driven member speed signals for providing a clutch engagement rate;

clutch torque calculating means responsive to said first and second clutch torque characteristics and said clutch engagement rate for calculating a clutch torque; and

control means responsive to said clutch torque for controlling said clutch providing optimum control of said clutch so as to smoothly engage said clutch without slipping at a starting mode and to operatively increase clutch torque of the clutch at a lockup mode when said engine torque signal abnormally increases, thereby preventing said clutch from overheating.

6. The control system according to claim 5, wherein

said clutch torque calculating means calculates said clutch torque (Tc) by the following equation:

space="preserve" listing-type="equation">Tc=Re·

TcL+(1-Re)·

Tcs

where Re is the clutch engagement rate, Tcs is the first clutch torque characteristic and Tcl is the second clutch torque characteristic.

7. The control system according to claim 5, wherein

said first sensor is a driven pulley speed sensor.

8. The control system according to claim 5, wherein

said clutch is an electromagnetic clutch.

9. The control system according to claim 8, wherein

said electromagnetic clutch is an electromagnetic powder clutch.