Anti-skid control system for motor vehicle
First Claim
1. An anti-skid control system for a motor vehicle, including a brake fluid pressure buildup-control mode and a brake fluid pressure reduction mode, which occur in anti-skid cycles, said anti-skid control system comprising:
- first valve means for alternately building up and holding brake fluid pressure during said brake fluid pressure buildup-control mode;
wheel speed measuring means for measuring a speed of each wheel of the motor vehicle and for providing a wheel velocity signal VW responsive to said speed;
peak detecting means for receiving said velocity signal VW and for detecting a high peak value VHP and a low peak value VLP of said velocity signal VW when said anti-skid control system is operated;
controller means for repetitively opening and closing said first valve means during said brake fluid pressure buildup-control mode, from a first time when said velocity signal VW has said high peak value VHP to a second time when said velocity signal VW has a value R, said value R corresponding to said velocity signal VW being equal to a reference velocity VWO at the second time, said reference velocity VWO having an initial value at the first time being less than said high peak value VHP by a predetermined velocity value Δ
V, having values which vary between the first time and the second time dependent upon a gradient θ
, and having a final value equal to said velocity signal VW at the second time corresponding to said value R;
acceleration measuring means for measuring wheel acceleration during a time after detection of said low peak value VLP by said peak detecting means on the basis of said velocity signal VW between a first value Va and a second value Vb of said velocity signal VW, said first value Va being dependent upon a predetermined rate of wheel velocity and said low peak value VLP, said second value Vb being dependent upon another predetermined rate of wheel velocity and said first value Va; and
determining means for determining at least one of said predetermined velocity value Δ
V, said gradient θ and
an initial pressure buildup time TP, for said brake fluid pressure buildup-control mode and in accordance with said measured wheel acceleration.
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Accused Products
Abstract
An anti-skid control system for a motor vehicle, includes a brake fluid pressure buildup-control mode and a brake fluid pressure reduction mode, each of which occur cyclically. In each buildup-control mode, a control valve is repetitively opened and closed so that brake fluid pressure buildup and holding operations are performed alternately. The time period of each buildup-control mode is from a high peak of a wheel speed signal until a point of intersection between a reference velocity VW0 and the wheel speed VW. The reference velocity VW0 has an initial point Q positioned under the high peak VHP of the wheel speed VW by a velocity value ΔV and extending straight at a gradient θ. The speed value ΔV, the gradient θ, and an initial pressure buildup time TP, in each building-control mode, are determined in accordance with the wheel acceleration in the preceding wheel acceleration, i.e., coefficient of friction of the road surface.
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Citations
8 Claims
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1. An anti-skid control system for a motor vehicle, including a brake fluid pressure buildup-control mode and a brake fluid pressure reduction mode, which occur in anti-skid cycles, said anti-skid control system comprising:
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first valve means for alternately building up and holding brake fluid pressure during said brake fluid pressure buildup-control mode; wheel speed measuring means for measuring a speed of each wheel of the motor vehicle and for providing a wheel velocity signal VW responsive to said speed; peak detecting means for receiving said velocity signal VW and for detecting a high peak value VHP and a low peak value VLP of said velocity signal VW when said anti-skid control system is operated; controller means for repetitively opening and closing said first valve means during said brake fluid pressure buildup-control mode, from a first time when said velocity signal VW has said high peak value VHP to a second time when said velocity signal VW has a value R, said value R corresponding to said velocity signal VW being equal to a reference velocity VWO at the second time, said reference velocity VWO having an initial value at the first time being less than said high peak value VHP by a predetermined velocity value Δ
V, having values which vary between the first time and the second time dependent upon a gradient θ
, and having a final value equal to said velocity signal VW at the second time corresponding to said value R;acceleration measuring means for measuring wheel acceleration during a time after detection of said low peak value VLP by said peak detecting means on the basis of said velocity signal VW between a first value Va and a second value Vb of said velocity signal VW, said first value Va being dependent upon a predetermined rate of wheel velocity and said low peak value VLP, said second value Vb being dependent upon another predetermined rate of wheel velocity and said first value Va; and determining means for determining at least one of said predetermined velocity value Δ
V, said gradient θ and
an initial pressure buildup time TP, for said brake fluid pressure buildup-control mode and in accordance with said measured wheel acceleration. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An anti-skid control system for a motor vehicle, including a brake fluid pressure buildup-control mode and a brake fluid pressure reduction mode, each of which occurs in anti-skid cycles, said anti-skid brake control system comprising:
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first valve means for alternately building-up and holding brake fluid pressure during said brake fluid pressure buildup-control mode; second valve means for reducing brake fluid pressure during said brake fluid pressure reduction mode; wheel speed measuring means for measuring a speed of each wheel of the motor vehicle and for providing a wheel velocity signal VW responsive to said speed; peak detecting means for receiving said velocity signal VW and for determining a high peak value VHP and a low peak value VLP of said velocity signal VW when a wheel is braked; controller means for repetitively opening and closing said first valve means during said brake fluid pressure buildup-control mode, from a first time when said velocity signal VW has said high peak value VHP to a second time when said velocity signal VW has a value R, said value R corresponding to said velocity signal VW being equal to a reference velocity VWO at the second time, said reference velocity VWO having an initial value at the first time being less than said high peak value VHP by a predetermined velocity value Δ
V, having values which vary between the first time and the second time dependent upon a gradient, and having a final value equal to said velocity signal VW at the second time corresponding to said value R;acceleration measuring means for measuring wheel acceleration during a time after detection of said low peak value VLP by said peak detecting means on the basis of said velocity signal VW between a first value Va and a second value Vb of said velocity signal VW, said first value Va being dependent upon a predetermined rate of wheel velocity and said low peak value VLP, said second value Vb being dependent upon another predetermined rate of wheel velocity and said first value Va; determining means for determining at least one of said predetermined velocity value Δ
V, said gradient θ and
an initial pressure buildup time TP, for said brake fluid pressure buildup-control mode in accordance with said measured wheel acceleration; andreduction control means for controlling opening of said second valve means during said brake fluid pressure reduction mode, from a time corresponding to an occurrence of said value R until a time corresponding to an occurrence of said low peak value VLP of said velocity signal VW. - View Dependent Claims (8)
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Specification