System for controlling an electromagnetic clutch for a vehicle

• US 4,675,817 A
• Filed: 01/29/1985
• Issued: 06/23/1987
• Est. Priority Date: 01/31/1984
• Status: Expired due to Fees

• Current Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Sakakiyama, Ryuzo, Miyawaki, Motohisa
• Primary Examiner(s): Gruber, Felix D.
• Application Number:
  US06/695,980
• Time in Patent Office: 875 Days
• Field of Search: 364/424.1, 192/0.03, 192/0.032, 192/0.033, 192/0.52, 192/0.75, 192/0.76, 192/3.58
• US Class Current: 701/67
• 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 2510/0638 Engine speed
• 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: F16D 2500/1022 Electromagnet
• CPC Class Codes: F16D 2500/10475 Magnetic field, e.g. electro-rheological, magnetisable particles
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/3108 Vehicle speed
• CPC Class Codes: F16D 2500/31453 Accelerator pedal position threshold, e.g. switch
• CPC Class Codes: F16D 2500/70418 Current
• CPC Class Codes: F16D 48/064 Control of electrically or electromagnetically actuated clutches F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 61/21 Providing engine brake control
• CPC Class Codes: F16H 61/66 specially adapted for continuously variable gearings control of exclusively fluid gearing F16H61/38

Abstract

A system for controlling an electromagnetic clutch has a vehicle speed sensor and an accelerator pedal switch. The clutch current is cut off at a low speed of a vehicle in response to a signal of the accelerator pedal switch at the release of an accelerator pedal. The system is arranged to supply a small drag current to the coil of the clutch in a very low vehicle speed range including stopping of the vehicle.

Claims

1. A system for controlling an electromagnetic clutch for a vehicle having an infinitely variable belt-drive transmission comprising

a vehicle speed sensor for producing a first vehicle speed signal when vehicle speed is higher than a predetermined first low speed and for producing a second vehicle speed signal when the vehicle speed is lower than a predetermined second low speed which is lower than the first low speed,

an accelerator pedal switch for producing an accelerator pedal signal when an accelerator pedal of the vehicle is released,

first means responsive to the first vehicle speed signal for supplying current to a coil of the electromagnetic clutch,

second means responsive to the accelerator pedal signal and absence of said first and second vehicle speed signals for cutting off the clutch current to the coil when the vehicle speed is between the first flow speed and the second low speed, and

third means responsive to the accelerator pedal signal and to the second vehicle speed signal for generating a drag current for the coil.

2. The system for controlling an electromagnetic clutch according to claim 1 further comprising

an engine speed sensor for producing a signal dependent on the engine speed, and

fourth means for supplying the clutch current to the coil so as to increase with an increase of the engine speed in response to the signal of the engine speed sensor at the start of the vehicle in the absence of said accelerator pedal signal.

3. The system according to claim 1 wherein

said first means responsive to the first vehicle speed signal for supplying lock-up clutch current to the coil of the electromagnetic clutch.

4. A method for controlling an electromagnetic clutch for a vehicle having an infinitely variable belt-drive transmission, comprising the steps of

detecting speed of the vehicle and determining when the vehicle speed is higher than a predetermined first low speed and determining when the vehicle speed is lower than a predetermined second low speed which is lower than the first low speed,

detecting release of an accelerator pedal of the vehicle,

supplying clutch current to a coil of the electromagnetic clutch when the vehicle speed is higher than the predetermined first low speed,

cutting off the clutch current to the coil when the accelerator pedal is released when the vehicle speed is between the first low speed and the second low speed, and

generating a drag current for the coil when the accelerator pedal is released when the vehicle speed is lower than the second low speed.