| 摘要 |
A control method for securing the lateral stability of a four-wheel drive vehicle is provided to increase the lateral stability and to prevent tight corner braking when the vehicle slips on a descending slope and in an engine brake region. The control method for securing the lateral stability of a four-wheel drive vehicle comprises the steps of: reading wheel speed and steering angle of front and rear wheels, position of a throttle valve, and a gradient value by sensors(S223); following the control method not to make the speed of the front and rear wheels different by applying duty to a magnetic clutch if a descending gradient of the vehicle is below a reference value and judging whether the vehicle is in an engine brake region if the descending gradient of the vehicle is over a reference value(S224); following the control method if not in the engine brake region and judging whether the vehicle slips or not if in the engine brake region(S225); executing a duty ramp up step if speed difference between the front and rear wheels is over an allowable value and judging whether the vehicle is in a tight corner braking region or not if the speed difference is below an allowable value(S227); controlling the vehicle by a first duty table preventing the speed of the front and rear wheels from being different from each other by the input of throttle position and vehicle speed by applying the duty to the magnetic clutch in the tight corner braking region and comparing the steering angle with the reference value if not in the tight corner braking region(S228,S231); and using a duty ratio output by adding a weight factor to a second duty table executing controls by a duty ratio varied according to a gradient and vehicle speed if the steering angle is over the reference value and using the second duty table if the steering angle is below the reference value(S229,S230,S232).
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