TRAILER MODE DETERMINATION DEVICE AND METHOD USING GRADIENT

A trailer mode determination device and method using a gradient is provided that a trailer mode determination method includes: calculating longitudinal acceleration-based gradient of a vehicle and determining whether a calculated value is valid; calculating clutch torque-based gradient and determining whether the calculated value is valid; determining whether the longitudinal acceleration-based gradient is greater than or equal to a predetermined reference gradient; determining whether vehicle speed and vehicle speed change amount are greater than or equal to predetermined values; calculating a difference between the longitudinal acceleration-based gradient (d1) and the clutch torque-based gradient (d2) when the vehicle speed and vehicle speed change amount are greater than or equal to a predetermined value; determining whether gradient difference (d1−d2) exceeds a predetermined normal range; and determining a trailer is mounted and a trailer mode is switch on when the gradient difference (d1−d2) exceeds the normal range.