An Objective Method of Driveability Evaluation using a Simulation Model for Hybrid Electric Vehicles

Conventionally, driveability evaluations in vehicles are subjectively assessed by professional test drivers in automotive companies. To solve limitation of repeatability and time-consuming, this paper proposes an objective method of evaluating driveability during acceleration and overtaking conditions in a hybrid electric vehicle. Selected criteria are the acceleration value obtained by the root mean square (RMS), the vibration dose value (VDV), the response delay, and the peak-to-peak value of the acceleration and jerk. For human vibration, measured acceleration signals are applied to frequency weighting functions on the basis of ISO 2631-1. An objective evaluation method for driveability is proposed by achieving a synthesis between the values calculated from each criterion and the correlated weighting factor obtained from the regression analysis of the subjective evaluations. The results by the proposed method with the target HEV are compared to those of the subjective evaluations during acceleration condition and while overtaking. A HEV dynamic model is also designed to utilize the proposed method. The characteristics of two types of strategies for HEVs are designed and analyzed. Finally, a driveability evaluation for each control strategy is performed and the results are compared using the proposed evaluation method.