Anti-blocking system for a road vehicle having a hydraulic multi-circuit brake installation
First Claim
1. An anti-blocking system for a road vehicle having a hydraulic multi-circuit brake installation operable to be changed over by an electrohydraulic changeover means from a functional condition which corresponds, in the sense of a fixed determination of the front axle/rear axle braking force distribution, to a dimensioning for a stable driving behavior up to the highest possible values of the braking of the vehicle, into a functional condition which corresponds, also in the sense of a fixed determination of said ratio,to a dimensioning of the latter for a higher proportion of the rear axle braking force, whereby the anti-blocking system operates according to the principle of keeping the braking slippage of the vehicle wheels within a range of values compatible both with good braking deceleration and with adequate driving stability, comprising brake pressure regulating valve means for the control of brake pressure build-up phases, brake pressure maintaining phases and brake pressure reduction phases, the brake pressure regulating valve means being operable to be activated into coresponding functional positions by output signals of an electronic control means which generates the signals necessary for the control of the different regulation phases in correct sequence and combination for the regulation from a comparative and differentiating processing of wheel velocity sensor output signals characteristic of the movement behavior of the vehicle wheels, the changeover means being operable at the commencement of a braking to control the brake installation into that functional condition which coresponds to the braking force distribution with the higher rear axle braking force proportion in such a manner that as long as the regulation is effective only in the rear axle braking circuit, the anti-blocking system operates on the principle of keeping the braking slippage λ
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H occurring at the rear axle in relation to the braking slippage λ
V occurring at the front axle within a range of values given by the relation
space="preserve" listing-type="equation">λ
.sub.V <
λ
.sub.H <
λ
.sub.V +Δ
λ
,wherein Δ
λ
is a prescribed limit of the slippage difference by which the rear axle braking slippage λ
H may exceed the braking slippage λ
V in the front axle braking circuit, while the value Δ
λ
is between about 2% and 6%, and that upon the commencement of the anti-blocking regulations at least at one of the front wheels of the vehicle the ABS is changed over to that functional condition, in which it operates on the principle of keeping the respective relative braking slippage λ
R referred to a reference velocity vF assumed as representative of the vehicle speed, which is defined by the relation ##EQU1## wherein vR is the wheel velocity of the vehicle wheel subjected to the regulation, both at the front axle and at the rear axle, within a range of values delimited by a slippage threshold λ
2 which is at most greater by about 2% to 4% than the braking slippage associated with the maximum tangential force transmission capacity of the vehicle wheels.
1 Assignment
0 Petitions
Accused Products
Abstract
An anti-blocking system for a road vehicle having a hydraulic service brake installation constructed as a dual-circuit brake installation with a front axle/rear axle brake circuit distribution which is adjustable to different values m1 and m2 of the front axle/rear axle braking force distribution, whereby the one value m1 corresponds to a braking force distribution optimized in the sense of driving stability and the other value corresponds to a relatively higher value of the rear axle braking force proportion. As long as the regulation is effective only at the rear axle, this anti-blocking system operates according to the principle of keeping a braking slippage λH occurring in the rear axle brake circuit within the range of values delimited by the relation λV +Δλ≦λH ≦λV +Δλ in relation to a braking slippage λV occurring in the front axle brake circuit, whereby Δλ designates a permissive slippage differential of about 4% and Δλ'"'"'≈Δλ/2. As soon as the anti-blocking regulation is also effective on the front axle, both the latter and the rear axle are regulated according to the principle of keeping both the front axle braking slippage λV and the rear axle braking slippage λH within the same range of values delimited by an upper limit of the braking slippage which is compatible with good braking deceleration and equally good driving stability.
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Citations
14 Claims
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1. An anti-blocking system for a road vehicle having a hydraulic multi-circuit brake installation operable to be changed over by an electrohydraulic changeover means from a functional condition which corresponds, in the sense of a fixed determination of the front axle/rear axle braking force distribution, to a dimensioning for a stable driving behavior up to the highest possible values of the braking of the vehicle, into a functional condition which corresponds, also in the sense of a fixed determination of said ratio,to a dimensioning of the latter for a higher proportion of the rear axle braking force, whereby the anti-blocking system operates according to the principle of keeping the braking slippage of the vehicle wheels within a range of values compatible both with good braking deceleration and with adequate driving stability, comprising brake pressure regulating valve means for the control of brake pressure build-up phases, brake pressure maintaining phases and brake pressure reduction phases, the brake pressure regulating valve means being operable to be activated into coresponding functional positions by output signals of an electronic control means which generates the signals necessary for the control of the different regulation phases in correct sequence and combination for the regulation from a comparative and differentiating processing of wheel velocity sensor output signals characteristic of the movement behavior of the vehicle wheels, the changeover means being operable at the commencement of a braking to control the brake installation into that functional condition which coresponds to the braking force distribution with the higher rear axle braking force proportion in such a manner that as long as the regulation is effective only in the rear axle braking circuit, the anti-blocking system operates on the principle of keeping the braking slippage λ
-
H occurring at the rear axle in relation to the braking slippage λ
V occurring at the front axle within a range of values given by the relation
space="preserve" listing-type="equation">λ
.sub.V <
λ
.sub.H <
λ
.sub.V +Δ
λ
,wherein Δ
λ
is a prescribed limit of the slippage difference by which the rear axle braking slippage λ
H may exceed the braking slippage λ
V in the front axle braking circuit, while the value Δ
λ
is between about 2% and 6%, and that upon the commencement of the anti-blocking regulations at least at one of the front wheels of the vehicle the ABS is changed over to that functional condition, in which it operates on the principle of keeping the respective relative braking slippage λ
R referred to a reference velocity vF assumed as representative of the vehicle speed, which is defined by the relation ##EQU1## wherein vR is the wheel velocity of the vehicle wheel subjected to the regulation, both at the front axle and at the rear axle, within a range of values delimited by a slippage threshold λ
2 which is at most greater by about 2% to 4% than the braking slippage associated with the maximum tangential force transmission capacity of the vehicle wheels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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H occurring at the rear axle in relation to the braking slippage λ
Specification