Patent ID: 7620504
Filing Date: 2009-11-17
Classification: B60G,B60T,B60W

Abstract:
1. A road-surface condition estimating device, comprising: driving-torque detecting means that detects a driving torque of an engine; longitudinal-acceleration detecting means that detects a longitudinal acceleration of the vehicle; driving-torque difference-value calculating means that calculates a difference between a currently detected driving torque of the engine and a previously detected driving torque of the engine as a driving-torque difference value; inertial-force difference-value calculating means that calculates a difference between a current inertial force of the vehicle and a previous inertial force of the vehicle as an inertial-force difference value on the basis of the longitudinal acceleration; inertial-force change-amount difference-value calculating means that calculates a difference between a current amount of change in inertial force of the vehicle and a previous amount of change in inertial force of the vehicle as an inertial-force change-amount difference value on the basis of the longitudinal acceleration; determination-coefficient calculating means that calculates at least one of a first determination coefficient and a second determination coefficient on the basis of a state equation related to the inertial-force change-amount difference value, the state equation being formed by adding a first arithmetic term to a second arithmetic term, the first arithmetic term being obtained by multiplying the inertial-force difference value by the first determination coefficient, the second arithmetic term being obtained by multiplying the driving-torque difference value by the second determination coefficient; and road-surface-condition determining means that determines a road-surface condition on the basis of the at least one of the first determination coefficient and the second determination coefficient.