Patent EP0133598A2 successfully refreshed from Google Patents.
EP0133598A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Antiskid control with surface friction compensation by prolonged down-pressure operation
Assignee: Denso Corp
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Filing: 1984-08-07
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Granted: —
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Expires: 2004-08-07
Abstract
Abstract in an antiskid control system for a motor vehicle, the speed and acceleration of at least one vehicle wheel are detected and from the detected wheel speed is estimated the speed of the vehicle. First and second variable threshold values are derived from the vehicle speed. The wheel speed and acceleration are compared with the first and second thresholds, respectively, to estimate the level of road surface friction and to operate solenoid-operated hydraulic brake pressure decreasing means. The operating period of the pressure decreasing means is controlled in accordance with the estimated road surface friction to prevent excessive reduction of the brake pressure and premature locking of wheels.
Inventors
- 👤 Syouichi Masaki
- 👤 Kimio Tamura
- 👤 Teruyoshi Wakao
- 👤 Noriyuki Nakashima
- 👤 Ken Asami
- 👤 Kazunori Sakai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 16:45
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/176; B60T8/1761; B60T8/17616; B60T8/172; B60T8/32; B60T8/88; B60T8/885; B60T2270/00; B60T2270/40; B60T2270/415; B60T2270/416
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
148 words
An antiskid control system for the hydraulic braking system of a wheeled vehicle having means for decreasing the fluid pressure of the braking system at a variable rate, comprising: means for detecting the speed of a vehicle wheel; means for deriving the acceleration of said wheel; means for detecting the speed of said vehicle; means for deriving a speed threshold variable as a function of said vehicle speed and an acceleration threshold variable as a function of said vehicle speed; means for comparing said wheel speed and said wheel acceleration with said speed and acceleration thresholds, respectively; means for estimating the level of road surface friction based upon outputs of said comparing means; means for operating said pressure decreasing means according to the outputs of said comparing means; and means for extending the operating period of said pressure decreasing means in accordance with the estimated road surface friction.
Claim 2
Dependent Claim
148 words
An antiskid control system for the hydraulic braking system of a wheeled vehicle having means for decreasing the fluid pressure of the braking system at a variable rate, comprising: means for detecting the speed of a vehicle wheel; means for deriving the acceleration of said wheel; means for detecting the speed of said vehicle; means for deriving a speed threshold variable as a function of said vehicle speed and an acceleration threshold variable as a function of said vehicle speed; means for comparing said wheel speed and said wheel acceleration with said speed and acceleration thresholds, respectively; means for estimating the level of road surface friction based upon outputs of said comparing means; means for operating said pressure decreasing means according to the outputs of said comparing means; and means for extending the operating period of said pressure decreasing means in accordance with the estimated road surface friction.
Claim 3
Dependent Claim
29 words
An antiskid control system as claimed in claim 1, wherein said period extending means comprises means for varying said acceleration threshold in response to the estimated road surface friction.
Claim 4
Dependent Claim
73 words
An antiskid control system as claimed in claim 1, wherein said estimating means comprises means for deriving first, second and third values respectively representing high, medium and low levels of road surface friction from said outputs of said comparing means, and said period extending means comprises means for causing said pressure decreasing means to operate for shorter, medium and longer periods of time in response to said first, second and third values, respectively.
Claim 5
Dependent Claim
159 words
An antiskid control system for the hydraulic braking system of a wheeled vehicle having means for decreasing the fluid pressure of the braking system at a variable rate comprising: means for detecting the speed of a vehicle wheel; and data processing means programmed to perform the steps of: a) deriving an acceleration of the wheel from the detected wheel speed; b) detecting the speed of said vehicle; c) deriving a speed threshold from the vehicle speed and an acceleration threshold from the vehicle speed; d) comparing the wheel speed and the wheel acceleration with said speed and acceleration thresholds, respectively; e) operating said pressure decreasing means according to the results of the step (d); f) simultaneously with the step (e), estimating the level of road surface friction based on the results of the step (d); and g) extending the operating period of said pressure decreasing means according to the level of road surface friction estimated by the step (f).
Claim 6
Dependent Claim
159 words
An antiskid control system for the hydraulic braking system of a wheeled vehicle having means for decreasing the fluid pressure of the braking system at a variable rate comprising: means for detecting the speed of a vehicle wheel; and data processing means programmed to perform the steps of: a) deriving an acceleration of the wheel from the detected wheel speed; b) detecting the speed of said vehicle; c) deriving a speed threshold from the vehicle speed and an acceleration threshold from the vehicle speed; d) comparing the wheel speed and the wheel acceleration with said speed and acceleration thresholds, respectively; e) operating said pressure decreasing means according to the results of the step (d); f) simultaneously with the step (e), estimating the level of road surface friction based on the results of the step (d); and g) extending the operating period of said pressure decreasing means according to the level of road surface friction estimated by the step (f).
Claim 7
Dependent Claim
62 words
An antiskid control system as claimed in claim 4, wherein the step (f) comprises deriving first, second and third values respectively representing high, medium and low values of road surface friction, and wherein the step (g) comprises causing said pressure decreasing means to operate for shorter, medium and longer periods of time respectively in response to said first, second and third values.
Claim 8
Dependent Claim
169 words
An antiskid control system for the hydraulic braking system of a wheeled vehicle having means for decreasing the the fluid pressure of the braking system at a variable rate comprising: means for detecting the speed of rotation of at least one of said wheels; and data processing means programmed to perform the steps of: a) deriving an acceleration of the wheel from the detected wheel speed; b) detecting the speed of said vehicle; c) deriving a speed threshold from the vehicle speed and an acceleration threshold from the vehicle speed; d) comparing the wheel speed and the wheel acceleration with said speed and acceleration thresholds, respectively; e) estimating the level of road surface friction basef on the results of the step (d); and f) varying said acceleration threshold according to the level estimated by the step (e); g) comparing said wheel speed and said wheel acceleration with said varied speed and acceleration thresholds, respectively; and h) operating said pressure decreasing means according to the results of the step (g).
Claim 9
Dependent Claim
169 words
An antiskid control system for the hydraulic braking system of a wheeled vehicle having means for decreasing the the fluid pressure of the braking system at a variable rate comprising: means for detecting the speed of rotation of at least one of said wheels; and data processing means programmed to perform the steps of: a) deriving an acceleration of the wheel from the detected wheel speed; b) detecting the speed of said vehicle; c) deriving a speed threshold from the vehicle speed and an acceleration threshold from the vehicle speed; d) comparing the wheel speed and the wheel acceleration with said speed and acceleration thresholds, respectively; e) estimating the level of road surface friction basef on the results of the step (d); and f) varying said acceleration threshold according to the level estimated by the step (e); g) comparing said wheel speed and said wheel acceleration with said varied speed and acceleration thresholds, respectively; and h) operating said pressure decreasing means according to the results of the step (g).
Claim 10
Dependent Claim
27 words
An antiskid control system as claimed in claim 6, wherein the step (f) comprises varying said speed threshold according to the level estimated by the step (e).
Claim 11
Dependent Claim
49 words
An antiskid control system as claimed in claim 6, wherein the step (e) comprises deriving first, second and third values respectively representing high, medium and low values of road surface friction, and wherein the step (f) comprises varying said acceleration threshold in response to said second and third values.
References Cited (Backward Citations)
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