Vehicle behavior control device

1. A vehicle behavior control device for controlling a behavior of a vehicle having steerable front road wheels, comprising:

driving force control part configured to perform control to reduce a driving force for the vehicle according to a yaw rate-related quantity which is related to a yaw rate of the vehicle; and

understeer-causing factor acquisition part configured to acquire an understeer-causing state of the vehicle which is a factor causing understeer,

wherein:

the driving force control part is further configured to perform control to, after reducing the driving force, increase the driving force at a change rate decided based on the understeer-causing state of the vehicle acquired by the understeer-causing factor acquisition part;

the understeer-causing factor acquisition part is operable to acquire a gross weight of the vehicle, as the understeer-causing state of the vehicle; and

the driving force control part is operable to reduce a change rate during increasing of the driving force to a smaller value, as the gross weight of the vehicle acquired by the understeer-causing factor acquisition part becomes larger.

2. The vehicle behavior control device as recited in claim 1 , wherein the driving force control part is operable, when a steering wheel angle of the vehicle is increasing and the yaw rate-related quantity is increasing, to reduce the driving force according to the yaw rate-related quantity being increasing, and, subsequently, when the steering wheel angle decreases or becomes constant, to increase the driving force.

3. A vehicle behavior control device for controlling a behavior of a vehicle having steerable front road wheels, comprising:

driving force control part configured to perform control to reduce a driving force for the vehicle according to a yaw rate-related quantity which is related to a yaw rate of the vehicle; and

understeer-causing factor acquisition part configured to acquire an understeer-causing state of the vehicle which is a factor causing understeer, wherein:

the driving force control part is further configured to perform control to, after reducing the driving force, increase the driving force at a change rate decided based on the understeer-causing state of the vehicle acquired by the understeer-causing factor acquisition part;

the understeer-causing factor acquisition part is operable to acquire an elapsed period of time after installation of tires in the vehicle, as the understeer-causing state of the vehicle; and

the driving force control part is operable to reduce a change rate during increasing of the driving force to a smaller value, as the elapsed period of time after installation of tires in the vehicle, acquired by the understeer-causing factor acquisition part becomes larger.

4. The vehicle behavior control device as recited in claim 3 , wherein the driving force control part is operable, when a steering wheel angle of the vehicle is increasing and the yaw rate-related quantity is increasing, to reduce the driving force according to the yaw rate-related quantity being increasing, and, subsequently, when the steering wheel angle decreases or becomes constant, to increase the driving force.

5. A vehicle control device comprising a controller to which at least a steering wheel angle, an accelerator position and a vehicle speed are input, and which is configured to control a driving force output from a driving force generator based on the steering wheel angle, the accelerator position and the vehicle speed, wherein the controller is configured to:

reduce the driving force so as to generate an additional deceleration to be added to the vehicle according to steering speed, with reference to a map defining the additional deceleration to be set according to the steering speed, when the steering wheel angle is increasing and the steering speed is not decreasing;

reduce the driving force so as to generate the additional deceleration at the maximum steering speed when the steering wheel angle is increasing and the steering speed is decreasing;

increase the driving force so as to reduce the additional deceleration when the steering wheel angle is not increasing; and

reduce a reduction rate of the additional deceleration during the decreasing thereof to a smaller value, as a gross weight of the vehicle becomes larger.