Patent ID: 6498974
Filing Date: 2002-12-24
Classification: B60K,B60W,Y10T

Abstract:
A system for controlling a transfer case which is operatively disposed within a four-wheel drive vehicle of the type having a front driveshaft which rotates at a first speed during a first interval of time and at a second speed during a second interval of time, and a rear driveshaft which rotates at a third speed during said first interval of time and at a fourth speed during said second interval of time, said transfer case being adapted to selectively provide torque to said front and said rear driveshaft, said system comprising:a first sensor which measures said first speed and generates a first signal which represents said first speed, and which measures said second speed and generates a second signal which represents said second speed; a second sensor which measures said third speed and generates a third signal which represents said third speed, and which measures said fourth speed and generates a fourth signal which represents said fourth speed; and a controller which is communicatively coupled to said transfer case and to said first sensor and to said second sensor, which receives said first, second, third and fourth signals, which utilizes said first signal and said third signal to calculate a first error value, and which utilizes said second signal and said fourth signal to calculate a second error value, said controller being further adapted to selectively generate an output signal which is derived based upon said first error value and said second error value, said output signal being effective to selectively control said torque which is transferred to said front and said rear driveshaft; wherein said first interval of time occurs after said second interval of time and wherein said first error value is equal to said third speed minus said first speed and a first allowable slip value and said second error value is equal to said fourth speed minus said second speed and a second allowable slip value.