Method and circuit configuration for controlling an anti-lock brake system for automotive vehicles with all-wheel drive

Claim 3

A method as claimed in claim 1, wherein one start limit value is predetermined in the range between 0.1 g and 0.5 g.

Claim 4

A method as claimed in claim 2, wherein one start minimum period of time is predetermined in the range between 40 msecs to 200 msecs.

Claim 7

A method as claimed in claim 4, wherein upon detection of a wheel rotational behavior typical of spinning and upon rise of the vehicle reference speed immediately subsequent to a slip-controlled braking action, a control or control action which may be lasting at this point of time will be terminated prematurely.

Claim 8

A circuit configuration for implementing a method for controlling an anti-lock brake system for automotive vehicles with all-wheel drive, comprising sensor means operatively coupled to a motor vehicle for the generation of electric signals representative of the rotational behavior of the vehicle wheels, and comprising circuit means for the conditioning, processing and logic combining of the sensor signals and for the generation of braking pressure control signals as a function of slip and deceleration or acceleration of the individual wheels, wherein a vehicle reference speed is derived from the information about the rotational behavior of the wheels and which is compared with the instantaneous speed of the individual vehicle wheels, and comprising switching means for influencing the control upon the occurrence of spinning tendencies, wherein upon detection of a wheel rotational behavior typical of spinning or a spinning tendency and upon attainment of predetermined start conditions and attainment or exceeding of predetermined limit values, said switching means are operable to effect a change-over of a control cycle to a second control concept in which the instantaneous wheel slip is deleted as a control signal whereby the braking pressure is controllable as a function of the wheel acceleration and wheel deceleration; wherein the switching means are operable to cause a switching back of the control cycle to a normal control, in which the braking pressure is controllable in dependence on wheel slip and wheel deceleration or wheel acceleration, as soon as at least one vehicle wheel shows a stable rotational behavior; and, wherein a digital counter is included as a feedback integrator means (8) which, as soon as the start conditions are fulfilled, is put into operation and which integrates the rise, i.e., the differential quotient (b REF ), of the vehicle reference speed (V REF ) with a predetermined time constant.

Claim 9

A circuit configuration for implementing a method for controlling an anti-lock brake system for automotive vehicles with all-wheel drive, comprising sensor means operatively coupled to a motor vehicle for the generation of electric signals representative of the rotational behavior of the vehicle wheels, and comprising circuit means for the conditioning, processing and logic combining of the sensor signals and for the generation of braking pressure control signals as a function of slip and deceleration or acceleration of the individual wheels, wherein a vehicle reference speed is derived from the information about the rotational behavior of the wheels and which is compared with the instantaneous speed of the individual vehicle wheels, and comprising switching means for influencing the control upon the occurrence of spinning tendencies, wherein upon detection of a wheel rotational behavior typical of spinning or a spinning tendency and upon attainment of predetermined start conditions and attainment or exceeding of predetermined limit values, said switching means are operable to effect a change-over of a control cycle to a second control concept in which the instantaneous wheel slip is deleted as a control signal whereby the braking pressure is controllable as a function of the wheel acceleration and wheel deceleration; wherein the switching means are operable to cause a switching back of the control cycle to a normal control, in which the braking pressure is controllable in dependence on wheel slip and wheel deceleration or wheel acceleration, as soon as at least one vehicle wheel shows a stable rotational behavior; and, wherein a digital counter is included as a feedback integrator means (8) which, as soon as the start conditions are fulfilled, is put into operation and which integrates the rise, i.e., the differential quotient (b REF ), of the vehicle reference speed (V REF ) with a predetermined time constant.

Claim 10

A circuit configuration as claimed in claim 6, wherein the integration time constant is approximated to the minimum vehicle acceleration at low frictional coefficient.

Claim 11

A circuit configuration as claimed in claim 7, wherein a value in the range between 0.1 g and 0.3 g is determined as an integration time constant.

Claim 12

A circuit configuration as claimed in claim 8, wherein said circuit configuration changes the integration time constant over to a considerably higher value (B Min2 ) when the vehicle reference speed shows a spinning tendency over a predefined longer period of time.

Claim 13

A circuit configuration as claimed in claim 9, wherein change-over to the greater time constant is performed as soon as the gradient of the vehicle reference speed has dropped to a predetermined value, to a value in the range between +0.2 g and -0.2 g.

Claim 14

A circuit configuration as claimed in claim 10, wherein the event of dropping of the gradient of the vehicle reference speed below a predetermined value of -0.2 g, the integration is continued with the smaller time constant.

Claim 15

A circuit configuration as claimed in claim 11, wherein said circuit means changes the integration time constant over to a value increased by one to two decimal powers.

Claim 16

A circuit configuration as claimed in claim 12, wherein during a control cycle, said integrator means (8) is set to zero as soon as a vehicle wheel shows stable rotational behavior, and which integrator (8) is put into operation again as soon as the start conditions are fulfilled.

Claim 17

A circuit configuration as claimed in claim 12, wherein during a control cycle, said integrator means (8) is set to zero as soon as a vehicle wheel shows stable rotational behavior, and is put into operation again as soon as the vehicle reference speed rises anew as soon as the differential quotient of the vehicle reference speed becomes positive.

Claim 18

A circuit configuration as claimed in claim 14, wherein said circuit means evaluates the deceleration of a vehicle wheel which lasts longer than a predetermined minimum time span and is subsequent to the acceleration of this wheel as a criterion for a stable rotational behavior of this wheel, not indicative of any spinning tendency.

Claim 19

A circuit configuration as claimed in claim 14, wherein a brake-actuating signal of a brake light switch is supplied to said digital counter to provided accelerated resetting of the counter.