Road surface condition determining system
First Claim
1. A road surface condition determining system for an automotive vehicle equipped with a traction control feature which provides prevention of relative rotation in excess of driving wheels against a road for determining an eventual road surface friction coefficient which is used in traction control, said road surface condition determining system comprising:
- speed detecting means for detecting a speed of the vehicle;
a torque sensor for detecting engine output torque and a selected transmission gear and for determining driving torque transmitted to the driving wheels based on said engine output torque and said selected transmission gear; and
road surface friction coefficient determining means for detecting longitudinal acceleration of the vehicle in a straight-ahead travel direction from a vehicle speed detected by said speed detecting means, for estimating, while traction control is being executed, a first road surface friction coefficient on the basis of said vehicle speed and said longitudinal acceleration and a second road surface friction coefficient on the basis of driving torque detected by said torque sensor, for determining either one of said first and second road surface friction coefficients which is larger than the other as an eventual road surface friction coefficient and for inhibiting determination of said second road surface friction coefficient as said eventual road surface friction coefficient for a predetermined period of time after commencement of said traction control.
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Accused Products
Abstract
A road surface condition determining system for an automotive vehicle equipped with a traction control feature determines, while the traction control is being executed, a first road surface friction coefficient on the basis of a vehicle speed and longitudinal acceleration and a second road surface friction coefficient on the basis of driving torque applied to the driving wheels and selects, as an eventual road surface friction coefficient, either one of the first and second road surface friction coefficients which is larger than the other.
113 Citations
15 Claims
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1. A road surface condition determining system for an automotive vehicle equipped with a traction control feature which provides prevention of relative rotation in excess of driving wheels against a road for determining an eventual road surface friction coefficient which is used in traction control, said road surface condition determining system comprising:
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speed detecting means for detecting a speed of the vehicle; a torque sensor for detecting engine output torque and a selected transmission gear and for determining driving torque transmitted to the driving wheels based on said engine output torque and said selected transmission gear; and road surface friction coefficient determining means for detecting longitudinal acceleration of the vehicle in a straight-ahead travel direction from a vehicle speed detected by said speed detecting means, for estimating, while traction control is being executed, a first road surface friction coefficient on the basis of said vehicle speed and said longitudinal acceleration and a second road surface friction coefficient on the basis of driving torque detected by said torque sensor, for determining either one of said first and second road surface friction coefficients which is larger than the other as an eventual road surface friction coefficient and for inhibiting determination of said second road surface friction coefficient as said eventual road surface friction coefficient for a predetermined period of time after commencement of said traction control. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A road surface condition determining system, for an automotive vehicle having an automatic transmission equipped with a torque converter, for determining an eventual road surface friction coefficient which is used in traction control which provides prevention of relative rotation in excess of driving wheels against a road, said road surface condition determining system comprising:
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speed detecting means for detecting a speed of the vehicle; a torque sensor for detecting engine output torque and a selected transmission gear and for determining driving torque transmitted to the driving wheels based on said engine output torque and said selected transmission gear; slip detecting means for detecting slipping rate of the torque converter; and road surface friction coefficient determining means for detecting longitudinal acceleration of the vehicle in a straight-ahead travel direction from a vehicle speed detected by said speed detecting means, for estimating, while traction control is being executed, a first road surface friction coefficient on the basis of said vehicle speed and said longitudinal acceleration and a second road surface friction coefficient on the basis of driving torque detected by said torque sensor, for correcting said second road surface friction coefficient with said slipping rate, for determining either one of said first road surface friction coefficients and said second road surface friction coefficient after correction which is larger than the other as an eventual road surface friction coefficient and for inhibiting determination of said second road surface friction coefficient as said eventual road surface friction coefficient for a predetermined period of time after commencement of said traction control. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification