Torque distribution control apparatus for 4 wheel driven vehicle

A torque distribution control apparatus of a four wheel drive vehicle, the vehicle comprising an engine mounted on said vehicle for supplying a driving force to front wheels and to rear wheels of the vehicle, an automatic gear train mounted on said vehicle and mechanically connected to said engine for changing a speed of the vehicle, and for transmitting a driving force to each of said wheels, a center differential mechanically interposed between said automatic gear train and said front and said rear wheels for changing a torque distribution ratio between said front and said rear wheels, a brake actuator hydro-mechanically connected to said wheels for stopping a rotation of any of said wheels by wheel cylinders installed on the vehicle for respective ones of said wheels, wheel speed sensors provided near said wheels for detecting speeds of respective ones of said wheels and for generating respective wheel speed signals, an acceleration sensor (81) mounted on said vehicle for detecting an acceleration in a running direction of said vehicle and for generating a longitudinal acceleration signal, and a vehicle driving controller responsive to said wheel speed signals for controlling said vehicle under driving conditions, said torque distribution control apparatus comprising:

• braking force control means connected to said brake actuator for controlling an optimum braking force to each of said wheels and for generating a braking force control signal;
• and
• torque distribution controller responsive to said longitudinal acceleration signal and said braking force control signal for calculating a weight distribution for said front and said rear wheels upon application of said braking force to said front wheels or said rear wheels, and for producing a weight distribution signal;
• wherein
• said torque distribution controller is operated responsive to said weight distribution signal for applying an engaging force to said center differential in accordance with a predetermined equation based upon said weight distribution so as to stabilize a controllability of said vehicle in various driving conditions and to improve a response characteristic during a running of the vehicle on a road.

A torque distribution control apparatus of a four wheel drive vehicle, the vehicle comprising an engine mounted on said vehicle for supplying a driving force to front wheels and to rear wheels of the vehicle, an automatic gear train mounted on said vehicle and mechanically connected to said engine for changing a speed of the vehicle and for transmitting a driving force to each of said wheels, a center differential mechanically interposed between said automatic gear train and said front and said rear wheels for changing a torque distribution ratio between said front and said rear wheels, a brake actuator hydromechanically connected to all of said wheels for stopping a rotation of any one of said wheels by wheel cylinders installed on the vehicle for respective ones of said wheels, wheel speed sensors provided near said wheels for detecting speeds of respective ones of said wheels and for generating respective wheel speed signals, an acceleration sensor mounted on said vehicle for detecting an acceleration in a running direction of said vehicle and for generating a longitudinal acceleration signal, and a vehicle driving controller responsive to said wheel speed signals for controlling said vehicle under driving conditions, said torque distribution control apparatus comprising:

• braking force control means connected to said brake actuator for controlling a braking force to each of said wheels, and for generating a braking force control signal;
• and
• a torque distribution controller responsive to said longitudinal acceleration signal and said braking force control signal for calculating a turning capability of said vehicle when said braking force is applied to at least one of said front wheels and said rear wheels while turning and for producing a turning capability signal;
• wherein
• said torque distribution controller is operated responsive to said turning capability signal for applying an engaging force to said center differential in accordance with a turning capability of said vehicle so as to stabilize a controllability of said vehicle in over-steering or under-steering conditions, and to improve a response characteristic during a running of the vehicle on a road.