Vehicle ride comfort is significantly influenced by powertrain torsional vibration. A multi-condition and multi-index evaluation method of the torsional vibration of the powertrain is proposed in this paper, which selects different evaluation indices according to the characteristics of different working conditions. First, the torsional vibration excitation source of the powertrain is analyzed. The selected indices are the speed amplitude value obtained with the root mean square value, the vibration dose value, the peak-to-peak value, the vibration isolation rate (
), and the speed fluctuation attenuation rate (
). Second, the torsional vibration characteristics of ignition, idle, startup, acceleration, deceleration, and switching from tip-in to tip-out are analyzed, and the torsional vibration evaluation indices of each working condition are determined. Then the torsional characteristics of a dual-mass flywheel (DMF) are tested before and after optimization, and the vehicle is tested according to the selected working conditions. Finally, by removing the trend term in the extracted data, the speed amplitude is obtained to calculate the evaluation indices for each working condition. The test results show that the damping performance is improved after the optimization of the DMF, and the evaluation indices under different working conditions are improved by approximately 7% in general, the magnitude of the indices under each working condition showed the same trend, which verifies the feasibility of the evaluation for the multi-condition and multi-index methods and provides references for evaluating the torsional vibration of the powertrain.
