The Effect of Displaying Kinetic Energy on Hybrid Electric Vehicle Drivers’ Evaluation of Regenerative Braking

Abstract

More energy efficient and sustainable systems become increasingly widespread in automotive applications (e.g., hybrid electric vehicles; HEVs). Yet, their real-world energy efficiency strongly depends on driver behaviour and, often, showing optimal eco-driving behaviour is challenging especially if energy dynamics are not sufficiently represented in the driver interface. For example, previous research indicated that HEV drivers try to actively utilize and regain electric energy, without sufficiently considering conversion losses that are part of this process (i.e., energy conversion fallacy). One possible explanation is that HEV drivers do not actively consider kinetic energy while driving, mainly because it is not represented in energy displays. The object of the present research was to examine whether drivers can be supported in a less biased perception of the efficiency of regenerative braking when an indicator of kinetic energy is also represented in the interface. To this end, we designed an online video experiment. Two displays were presented to drivers, a conventional energy flow display in which only electric energy resources were represented and an adapted display in which also kinetic energy resources were represented. Drivers rated the perceived energy efficiency of two types of deceleration scenarios, regenerative braking and neutral mode. The results provide first evidence that adding a representation of kinetic energy resources to displays of energy flows in HEVs can reduce drivers’ energy conversion fallacy.