Antiskid control method
First Claim
1. In a vehicle having brake fluid pressure piping divided into a first channel for right front and left rear wheels and a second channel for left front and right rear wheels, a pressure reducing device provided for antiskid control in each of said channels, a pressure reducing valve disposed in a fluid pressure transmission line leading to said rear wheel in each of said first and second channels, and a control circuit arranged to render said pressure reducing devices operative according to a sudden drop in the velocity of the wheels which results from brake application, an antiskid control method comprising determining whether the road surface is of a low or high coefficient of friction and controlling said pressure reducing device of each of said channels with a respective signal, selected as a reference signal in one of the following modes (a) or (b) chosen on the basis on said determination, from among signals representing wheel velocity values detected from said four wheels, wherein:
- mode (a) comprises, when the vehicle is running on a road surface of a low coefficient of friction on which the deceleration of the vehicle becomes low during brake application, selecting respective signals, each representing the velocity of a wheel rotating at a lower velocity, as the reference signal by comparing the velocity values of said front and rear wheels of each of said channels with each other; and
mode (b) comprises, when the vehicle is running on a road surface which is not of a low coefficient of friction, comparing signals representing the velocity values of said rear wheels of said two channels with each other, selecting the signal representing the higher rear wheel velocity, comparing the higher rear wheel velocity signal with signals representing the velocity values of said front wheels of said two channels, and selecting respective signals for said respective pressure reducing devices which represent a lower wheel velocity, respectively, among said signals compared.
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Accused Products
Abstract
In a method for antiskid control of a vehicle, the operating condition of a two-channel type antiskid control device is arranged to be shiftable according to the road surface condition, in such a manner that, in the case of a so-called split road surface condition, the braking force is maintained as much as possible on wheels which remain sufficiently in contact with the road surface, so that the brake distance can be prevented from lengthening without losing the maneuverability of the vehicle.
65 Citations
6 Claims
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1. In a vehicle having brake fluid pressure piping divided into a first channel for right front and left rear wheels and a second channel for left front and right rear wheels, a pressure reducing device provided for antiskid control in each of said channels, a pressure reducing valve disposed in a fluid pressure transmission line leading to said rear wheel in each of said first and second channels, and a control circuit arranged to render said pressure reducing devices operative according to a sudden drop in the velocity of the wheels which results from brake application, an antiskid control method comprising determining whether the road surface is of a low or high coefficient of friction and controlling said pressure reducing device of each of said channels with a respective signal, selected as a reference signal in one of the following modes (a) or (b) chosen on the basis on said determination, from among signals representing wheel velocity values detected from said four wheels, wherein:
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mode (a) comprises, when the vehicle is running on a road surface of a low coefficient of friction on which the deceleration of the vehicle becomes low during brake application, selecting respective signals, each representing the velocity of a wheel rotating at a lower velocity, as the reference signal by comparing the velocity values of said front and rear wheels of each of said channels with each other; and mode (b) comprises, when the vehicle is running on a road surface which is not of a low coefficient of friction, comparing signals representing the velocity values of said rear wheels of said two channels with each other, selecting the signal representing the higher rear wheel velocity, comparing the higher rear wheel velocity signal with signals representing the velocity values of said front wheels of said two channels, and selecting respective signals for said respective pressure reducing devices which represent a lower wheel velocity, respectively, among said signals compared. - View Dependent Claims (2, 3, 4, 5)
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6. In a vehicle having brake fluid pressure piping divided into a first channel for right front and left rear wheels and a second channel for left front and right rear wheels, a pressure reducing device provided for antiskid control in each of said channels, a pressure reducing valve disposed in a fluid pressure transmission line leading to said rear wheel in each of said first and second channels and a control circuit arranged to cause said pressure reducing devices to operate according to a sudden drop in the velocity of the wheels resulting from brake application, an antiskid control method comprising operating said pressure reducing device of each of said channels by comparing two wheel velocity signals representing the velocity values of the rear wheels of said two channels, selecting one of said signals representing a higher velocity value;
- comparing said rear wheel velocity signal thus selected with each of the wheel velocity signals representing velocity values of the front wheels of said channels, selecting the respective signals representing lower velocity values of said channel for operating said pressure reducing devices of said channels, respectively.
Specification