Driving force control apparatus for four-wheel drive vehicle

• US 20060037804A1
• Filed: 08/19/2005
• Published: 02/23/2006
• Est. Priority Date: 08/23/2004
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company), Mary Ashley Zimmermann
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Hara, Jiro, Sugo, Yasuhiko
• Granted Patent: US 7,434,647 B2
• Time in Patent Office: Days
• US Class Current: 180/249
• CPC Class Codes: B60K 17/35 including arrangements for suppressing or influencing the power transfer, e.g. viscous clutches differential gearing with locking devices F16H48/20
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch

Abstract

A driving force control apparatus for a four-wheel drive vehicle is provided for stably launching the vehicle irrespective of whichever condition of a road surface and whether or not a road is gradient. In the driving force control apparatus for a four-wheel drive vehicle configured to transmit a driving force of a prime mover directly to a left and a right main driving wheel and to a left and a right sub-driving wheel through a clutch, rotational speed sensors detect the rotational speed of the respective main driving wheels and sub-driving wheels, a 2/4 WD•ECU sets a fastening force of the clutch in accordance with a difference between the detected rotational speeds of the main driving wheels and the sub-driving wheels, determines that the four-wheel drive vehicle is in a slip stop state when at least one of the detected rotational speeds of the wheels is equal to or lower than a predetermined rotational speed, and corrects the clutch for the set fastening force when it determines that the four-wheel drive vehicle is in the slip stop state.

Claims

1. A driving force control apparatus for a four-wheel drive vehicle configured to transmit a driving force of a prime mover directly to a left and a right main driving wheel and to a left and a right sub-driving wheel through a clutch, said apparatus comprising:

rotational speed detecting means for detecting a rotational speed of each of said main driving wheels and said sub-driving wheels;

fastening force setting means for setting a fastening force of said clutch in accordance with a difference between the detected rotational speeds of said main driving wheels and said sub-driving wheels;

slip stop state determining means for determining that said four-wheel drive vehicle is in a slip stop state when at least one of the detected rotational speeds of said wheels is equal to or lower than a predetermined rotational speed; and

fastening force correcting means for correcting the fastening force of said clutch set by said fastening force setting means when said slip stop state determining means determines that said four-wheel drive vehicle is in the slip stop state.

2. A driving force control apparatus for a four-wheel drive vehicle according to claim 1, wherein said slip stop state determining means determines that said four-wheel drive vehicle is in the slip stop state when at least one wheel is rotating at a rotational speed equal to or lower than the predetermined rotational speed for a first predetermined time or longer.

3. A driving force control apparatus for a four-wheel drive vehicle according to claim 2, further comprising counting means for counting the number of times said slip stop state determining means determines that said four-wheel drive vehicle is in the slip stop state,

wherein said fastening force correcting means corrects said clutch for the fastening force in accordance with the counted count value.

4. A driving force control apparatus for a four-wheel drive vehicle according to claim 1, wherein said slip stop state determining means determines that said four-wheel drive vehicle has exited the slip stop state when all of said main driving wheels and said sub-driving wheels are rotating at rotational speeds exceeding the predetermined rotational speed for a second predetermined time or longer after said four-wheel drive vehicle is determined to be in the slip stop state.