The present work deals with the impact of alternative drive concepts on the driving dynamics of passenger cars. Introductory, conventional and alternative drive concepts and their differences in terms of driving dynamics are illustrated. The results of a literature survey concerning trends and concepts in future hybrid electric vehicles' chassis design do not see clear trends to new and or significantly modified chassis concepts, consequently a separate consideration of chassis in vehicles with conventional or alternative drive concepts is not required. The disclosed differences between conventional and alternative drive concepts show that the possibility of brake energy recuperation of hybrid electric vehicles can lead to significant effects in driving dynamics under combined longitudinal and lateral dynamics. Therefore, driving manoeuvres are compiled and analyzed in terms of the relevance for the recuperation. In this case, the standardized driving manoeuvre (DIN ISO 7975) 'braking-in-a-turn' proves to be purposeful to analyze the impacts of recuperation on the driving dynamics. In addition, the vehicle behaviour is analyzed during straight line braking with steering excitation as well as on ?-split road conditions, since interactions of drive train and chassis occur. To assess the results, the driving stability as well as the perceptibility of altered driving dynamics is considered. Based on the literature survey, a perception threshold of 3°/s of yaw rate is defined. The results of a simulation study with two different vehicle concepts (front/rear wheel drive) in three driving manoeuvres show, that regenerative braking can be used effectively over a wide range of deceleration levels. During a braking-in a-turn manoeuvre, regenerative braking at the front axle lead to a significant reduction of disturbing over steer reactions and can be used even at higher lateral accelerations. However, regenerative braking at the rear axle, in particular at braking in a turn on wet road surface conditions, may result in critical driving conditions. By limiting the maximum regenerative brake moment at higher wheel slip conditions, the driving stability can be ensured. The results of the other simulated driving manoeuvres show, that no perceptible differences in the driving dynamics occur at lower wheel slip values. (Author/publisher)
Abstract