| 摘要 |
PURPOSE:To enhance the durability of an automatic transmission and frictional engaging elements thereof without causing increase in dimension and weight, and also to enhance the fuel economy by increasing the line pressure together with the performance of differential limitation by a differential limiting device. CONSTITUTION:When a difference in rotational speed between front and rear wheels exceeds a predetermined value, the line pressure Pl is increased to make the transmission torque capacity of an automatic transmission 2 larger than a differential transmission torque capacity or an actual output torque, and accordingly, no slip occurs between frictional engaging elements in the automatic transmission 2. With such differential limiting operation, the difference between angular speeds of the front and rear wheels gradually decreases. The differential limiting torque is slightly lowered when this difference becomes zero, and accordingly, the output torque of the automatic transmission and the actual torque of the front wheel are reduced, and simultaneously or after that, such control that the line pressure Pl is increased is ceased, and the line pressure Pl is set to a pressure based upon normal control in accordance with a throttle opening degree and the like, thereby it is possible to lower the capacity of torque transmission through the automatic transmission. |
