Driving force control apparatus and method for a vehicle

A driving force control apparatus for a vehicle comprising:

• slip detection means for detecting a slip condition amount indicating the magnitude of a slip condition generated in driving wheels when starting or accelerating the vehicle;
• driving force control means for controlling an output of an engine equipped on the vehicle to control a driving force transmitted from the driving wheels to a road surface;
• vibration detection means for detecting occurrence of a vibration in the driving wheels, said vibration detection means including driving wheel speed detection means for detecting a rotational speed of the driving wheels, defining generation of a vibration in the driving wheels when a vibration is generated in the rotational speed of the driving wheels;
• control means including target driving torque setting means for setting a target value of a driving torque required to reduce a slip in the driving wheels as a target driving torque according to the slip condition amount detected by said slip detection means, and engine control means for controlling said driving force control means according to the target driving torque set by said target driving torque setting means, to reduce the engine output and suppress a slip of the driving wheels;
• and
• control regulation means for restricting a change in the driving force by said control means when said vibration detection means detects occurrence of a vibration in the driving wheels,
• wherein said target driving torque setting means includes
• acceleration detection means for detecting a running acceleration of the vehicle,
• reference driving torque setting means for setting a driving torque required for the vehicle to run at a running acceleration according to the running acceleration detected by said acceleration detection means as a reference driving torque,
• correction torque setting means for setting a correction torque as a driving torque reduction amount required to reduce a slip of the driving wheels according to the slip condition amount detected by said slip detection means, and
• correction means for correcting the reference driving torque set by said reference driving torque setting means by the correction torque set by the correction torque setting means to set the target driving torque,
• said control regulation means restricting the correction torque set by said correction torque setting means.

A driving force control method comprising the steps of:

• (a) detecting a slip condition amount generated in the driving wheels of the vehicle;
• (b) controlling a driving force, transmitted from the driving wheels to the road surface, to be reduced based upon the slip condition amount detected in step (a) to suppress a slip of the driving wheels;
• (c) detecting whether or not a vibration occurs in at least one of the driving wheels of the vehicle;
• and
• (d) inhibiting control to increase the reduced driving force upon detecting the existence of a vibration in step (c), wherein step (c) includes the substeps of,
• (c1) determining that the vehicle is traveling on a split road if frictional coefficients of the road surface contacting right and left driving wheels of the vehicle are different, and
• (c2) detecting that a vibration occurs based upon the detection that the vehicle, in step (c1), is traveling on a split road, wherein step (c1) includes the substeps of,
• detecting rotational speeds of the right and left driving wheels of the vehicle;
• and
• detecting that the vehicle is running on the split road upon detecting that a difference of the detected rotational speeds of the right and left driving wheels of the vehicle is greater than a predetermined value.