Exergy-based modeling framework for hybrid and electric ground vehicles

TL;DR

This paper introduces a novel exergy-based modeling framework for ground vehicles that quantifies and analyzes energy transfer and losses, aiding in the development of more efficient vehicle management strategies.

Contribution

It is the first to propose a comprehensive exergy-based analysis framework at the vehicle and powertrain level for ground vehicles.

Findings

The model effectively quantifies exergy transfer and destruction.

Case studies demonstrate the framework's ability to locate and rank sources of exergy losses.

The framework can guide strategies to minimize exergy losses in vehicle design.

Abstract

Exergy, or availability, is a thermodynamic concept representing the useful work that can be extracted from a system evolving from a given state to a reference state. It is also a system metric, formulated from the first and the second law of thermodynamics, encompassing the interactions between subsystems and the resulting entropy generation. In this paper, an exergy-based analysis for ground vehicles is proposed. The study, a first to the authors' knowledge, defines a comprehensive vehicle and powertrain-level modeling framework to quantify exergy transfer and destruction phenomena for the vehicle's longitudinal dynamics and its energy storage and conversion devices (namely, electrochemical energy storage, electric motor, and ICE). To show the capabilities of the proposed model in quantifying, locating, and ranking the sources of exergy losses, two case studies based on an electric vehicle and a parallel hybrid electric vehicle are analyzed considering a real-world driving cycle. This modeling framework can serve as a tool for the future development of ground vehicles management strategies aimed at minimizing exergy losses rather than fuel consumption.