CAE Simulation and Experimental Testing of a CVT Vehicle Shuffle

A low-frequency vehicle shuffle can be excited when a reversal of torque occurs in a vehicle's drivetrain. It usually occurs during a throttle tip-in or tip-out event, or a static engagement shift event. This drivetrain shuffle vibration can introduce a vehicle fore-aft vibration that may affect the customer satisfaction of ride comfort and/or powertrain performance. Vehicle test data of the seat track acceleration from a 30 MPH wide-open-throttle tip-out event suggested a strong coupling between the CVT drivetrain shuffle and vehicle fore-aft vibration. An ADAMS based CVT model was developed and integrated into a full vehicle model for dynamic simulation of this vehicle shuffle issue. CAE DOE studies were performed to identify key vehicle and powertrain design parameters that could directly impact the vehicle shuffle vibration. Experimental tests were performed to verify the CAE design improvements of the CVT vehicle shuffle vibration. Primary benefits of this developed model are to provide upfront CAE and multi-attribute optimization to achieve better ride comfort, driveability, and shift quality in CVT vehicles.