# US 5,704,872 A · Automatic vehicle clutch control

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- Number: US 5,704,872 A
- Document ID: US5704872A
- Status: Granted
- Kind: A
- Application number: 08/699,666
- Filed: 1996-08-19
- Granted: 1998-01-06
- Earliest claimed: 1995-08-21
- Assignees: Mercedes-Benz AG
- Inventors: Franz Kosik; Gunter Worner
- Web page: https://patentgrep.com/patent/US5704872A

## CPC

- F16D 48/066: {Control of fluid pressure, e.g. using an accumulator (F16D48/062, F16D48/068 take precedence)}
- B60W 30/18027: {Drive off, accelerating from standstill}
- F16D 48/08: Regulating clutch take-up on starting
- B60W 2510/0604: Throttle position
- B60W 2520/10: Longitudinal speed
- B60W 2540/10: Accelerator pedal position
- F16D 2500/10481: Automatic clutch, e.g. centrifugal masses
- F16D 2500/3026: Stroke
- F16D 2500/30806: Engaged transmission ratio
- F16D 2500/3101: Detection of a brake actuation by a sensor on the brake
- F16D 2500/3108: Vehicle speed
- F16D 2500/3111: Standing still, i.e. signal detecting when the vehicle is standing still or bellow a certain limit speed
- F16D 2500/3144: Accelerator pedal position
- F16D 2500/50206: Creep control
- F16D 2500/50224: Drive-off
- F16D 2500/7041: Position
- F16D 2500/70426: Clutch slip
- F16D 2500/7044: Output shaft torque
- F16D 2500/70663: State analysis; Analysing potential states of the machine and developing control strategies at each state
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT

## Abstract

In a method of controlling an automatic clutch arranged between an engine and a drive train of a vehicle in vehicle startup situations wherein the clutch is engaged to such a degree that only a small torque can be transmitted through the clutch and wherein the clutch is increasingly engaged when engine power output is increased, the clutch is immediately returned toward disengagement if, during vehicle startup, the engine power output requirements are suddenly reduced and, after a predetermined delay, the clutch is adjusted to the new situation that is to a standstill of the vehicle or to a renewed startup situation.

## Claims

### Claim 1

A method of controlling an automatic clutch arranged between a motor, especially an internal combustion engine, and a drive train of a vehicle in vehicle startup situations, wherein said clutch is automatically engaged to such a degree that only a small torque can be transmitted by the clutch which results in no more than creeping motion of said vehicle but wherein said clutch is increasingly engaged when an engine power output control member is actuated for increased engine power output, and wherein said clutch is immediately returned toward disengagement if, during vehicle startup, said engine power output control member is released and said clutch is then, after a predetermined delay, controlled in adaptation to the new situation--that is to a stand-still of the vehicle with brakes applied or to a renewed startup situation.

### Claim 2 (depends on 1)

A control method according to claim 1, wherein said clutch is fully disengaged only if the engine power output control element is returned to a position below a predetermined threshold value and/or the return of the engine power output control element to below said predetermined threshold value occurs rapidly.

### Claim 3 (depends on 1)

A control method according to claim 1, wherein said clutch is fully disengaged only if the vehicle speed falls below a predetermined small threshold value.

### Claim 4 (depends on 3)

A control method according to claim 3, wherein said predetermined small threshold value at which said clutch is fully disengaged depends on the gear in which a transmission disposed in the drive train of the vehicle is engaged.