Method of distributing brake pressure to the axles of a motor vehicle with an ABS pressure-medium brake
First Claim
1. A method of distributing brake pressure to axles of a motor vehicle having an ABS pressure-medium brake, an electrically acting anti-lock brake system (ABS) with an electronic centralized control and electrically controllable brake valves proximate the axles and comprising speed sensors which are assigned to the brakable wheels and serve as actual-value, instantaneous wheel speed sensors for an ABS control operative at a wheel brake pressure near a wheel lock limit, comprising the steps ofregulating automatically an inter-axle brake-pressure distribution φ
- in a slip range below a range in which the ABS control is operative in accordance with an evaluation of the wheel-speed signals supplied by the wheel-speed sensors and the exceeding of a first predeterminable limiting value ds, by a referred difference of inter-axle wheel speeds upon braking as a condition for a first regulation of said inter-axle brake-pressure distribution φ
,performing dynamically the first regulation when the limiting value ds1 is exceeded for intervention in individual brake applications in the sense of a continuously cyclic acquisition and processing of current actual wheel-speed differences to immediately influence the brake-pressure distribution while a respective braking operation is still underway, andmaking a second regulation in the manner of an adaptively predictive precontrol of the brake-pressure distribution φ
for any retardation levels is made the basis of the first regulation, by seeking mutually associated steady-state values of the referred inter-axle wheel speed difference and of the retardation in the case of previous brake-pressure distribution on the basis of predetermined limiting values for the time rate of change thereof, determining, after at least one initial brake application, parameters of a brake-pressure distribution function, as soon as steady-state values are present, then, after at least one initial brake application, in which function a setpoint deceleration demanded by a driver via a brake pedal is included, using the brake-pressure distribution as a basis for subsequent braking operations, and correcting the previous value of the brake-pressure distribution to a current value by the first regulation in the current cycle as soon as a second, smaller limiting value is exceeded by a steady-state value of the referred speed difference, after the determination of the parameters in the course of a subsequent brake application.
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Accused Products
Abstract
A method utilizes components of an existing anti-lock brake system (ABS) in order thereby to achieve an automatically self-optimizing inter-axle brake-pressure distribution acting far below the wheel lock limit. For this purpose, the brake pressure and, hence, the brake-force distribution are regulated axle-specifically far below the wheel lock limit too. An immediate dynamic intervention is, on one hand, effected in the case of sufficiently large wheel-speed differences between the axles. On the other hand, an adaptive predetermination of correct brake-force distributions is made the basis for each current regulating intervention. Even before the occurrence of large speed differences, the brake-force distribution expedient in each case for these is here predictively determined, stored, and, if required, correspondingly adapted to current requirements, i.e. corrected, in the course of subsequent dynamic braking demands. Requisite determination parameters are obtained for each journey either via characteristic diagrams specific to the family of vehicles or are determined individually on the individual vehicle by a learning approximation routine.
90 Citations
20 Claims
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1. A method of distributing brake pressure to axles of a motor vehicle having an ABS pressure-medium brake, an electrically acting anti-lock brake system (ABS) with an electronic centralized control and electrically controllable brake valves proximate the axles and comprising speed sensors which are assigned to the brakable wheels and serve as actual-value, instantaneous wheel speed sensors for an ABS control operative at a wheel brake pressure near a wheel lock limit, comprising the steps of
regulating automatically an inter-axle brake-pressure distribution φ - in a slip range below a range in which the ABS control is operative in accordance with an evaluation of the wheel-speed signals supplied by the wheel-speed sensors and the exceeding of a first predeterminable limiting value ds, by a referred difference of inter-axle wheel speeds upon braking as a condition for a first regulation of said inter-axle brake-pressure distribution φ
,performing dynamically the first regulation when the limiting value ds1 is exceeded for intervention in individual brake applications in the sense of a continuously cyclic acquisition and processing of current actual wheel-speed differences to immediately influence the brake-pressure distribution while a respective braking operation is still underway, and making a second regulation in the manner of an adaptively predictive precontrol of the brake-pressure distribution φ
for any retardation levels is made the basis of the first regulation, by seeking mutually associated steady-state values of the referred inter-axle wheel speed difference and of the retardation in the case of previous brake-pressure distribution on the basis of predetermined limiting values for the time rate of change thereof, determining, after at least one initial brake application, parameters of a brake-pressure distribution function, as soon as steady-state values are present, then, after at least one initial brake application, in which function a setpoint deceleration demanded by a driver via a brake pedal is included, using the brake-pressure distribution as a basis for subsequent braking operations, and correcting the previous value of the brake-pressure distribution to a current value by the first regulation in the current cycle as soon as a second, smaller limiting value is exceeded by a steady-state value of the referred speed difference, after the determination of the parameters in the course of a subsequent brake application. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
- in a slip range below a range in which the ABS control is operative in accordance with an evaluation of the wheel-speed signals supplied by the wheel-speed sensors and the exceeding of a first predeterminable limiting value ds, by a referred difference of inter-axle wheel speeds upon braking as a condition for a first regulation of said inter-axle brake-pressure distribution φ
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20. In a motor vehicle having an ABS pressure-medium brake associated with each vehicle wheel, an electrically-acting anti-lock brake system (ABS) with an electronic centralized control, and electrically controllable brake valves proximate axles of the vehicles and comprising speed sensors assigned to the brakable vehicle wheels operable to serve as actual-value, instantaneous wheels speed sensors for control of the ABS at a wheel brake pressure near a wheel lock limit, the improvement comprising means for distributing brake pressure to the axles by automatically regulating inter-axle brake pressure distribution φ
- in a slip range below a range in which the ABS control is operative in accordance with an evaluation of the wheel-speed signals supplied by the wheel-speed sensors using the exceeding of a first predeterminable limiting value ds, by a referred difference of inter-axle wheel speeds upon braking as a condition for a first regulation of said inter-axle brake-pressure distribution, performing dynamically the first regulation when the limiting value ds1 is exceeded, for intervention in individual brake application, in the sense of a continuously cyclic acquisition and processing of current actual wheel-speed differences to immediately influence the brake-pressure distribution while a respective braking operation is still underway, and making a second regulation in the manner of an adaptively predictive precontrol of the brake-pressure distribution φ
for any retardation levels the basis of the first regulation by seeking mutually associated steady-state values of the referred inter-axle speed difference and of the retardation in the case of a previous brake-pressure distribution φ
=(Pfront /Pread) on the basis of predetermined limiting values for the time rate of change thereof, determining after at least one initial brake application parameters of a brake-pressure distribution function as soon as steady-state values are present, then, after at least one initial brake application, in which function a setpoint deceleration demanded by a driver via a brake pedal is included, using the brake-pressure distribution as a basis for the subsequent braking operations, and correcting the old value of the brake-pressure distribution to a new value by the first regulation in the current cycle as soon as a second, smaller limiting value is exceeded by a steady-state value of the referred speed difference, after the determination of the parameters in the course of a subsequent brake application.
- in a slip range below a range in which the ABS control is operative in accordance with an evaluation of the wheel-speed signals supplied by the wheel-speed sensors using the exceeding of a first predeterminable limiting value ds, by a referred difference of inter-axle wheel speeds upon braking as a condition for a first regulation of said inter-axle brake-pressure distribution, performing dynamically the first regulation when the limiting value ds1 is exceeded, for intervention in individual brake application, in the sense of a continuously cyclic acquisition and processing of current actual wheel-speed differences to immediately influence the brake-pressure distribution while a respective braking operation is still underway, and making a second regulation in the manner of an adaptively predictive precontrol of the brake-pressure distribution φ
Specification