Experimental Validation of Eco-Driving and Eco-Heating Strategies for Connected and Automated HEVs

TL;DR

This study experimentally validates eco-driving and eco-heating strategies for connected hybrid electric vehicles, demonstrating significant energy savings through V2I communication, predictive optimization, and thermal energy storage during real-world city driving at cold temperatures.

Contribution

The paper introduces a real-time predictive optimization framework integrating eco-driving and eco-heating strategies using thermal energy storage in a hybrid electric vehicle.

Findings

Eco-driving reduces fuel consumption by 14.5%.

Eco-heating achieves 4.7% energy savings.

Combined strategies save over 19% energy compared to baseline.

Abstract

This paper presents experimental results that validate eco-driving and eco-heating strategies developed for connected and automated vehicles (CAVs). By exploiting vehicle-to-infrastructure (V2I) communications, traffic signal timing, and queue length estimations, optimized and smoothed speed profiles for the ego-vehicle are generated to reduce energy consumption. Next, the planned eco-trajectories are incorporated into a real-time predictive optimization framework that coordinates the cabin thermal load (in cold weather) with the speed preview, i.e., eco-heating. To enable eco-heating, the engine coolant (as the only heat source for cabin heating) and the cabin air are leveraged as two thermal energy storages. Our eco-heating strategy stores thermal energy in the engine coolant and cabin air while the vehicle is driving at high speeds, and releases the stored energy slowly during the vehicle stops for cabin heating without forcing the engine to idle to provide the heating source. To test and validate these solutions, a power-split hybrid electric vehicle (HEV) has been instrumented for cabin thermal management, allowing to regulate heating, ventilation, and air conditioning (HVAC) system inputs (cabin temperature setpoint and blower flow rate) in real-time. Experiments were conducted to demonstrate the energy-saving benefits of eco-driving and eco-heating strategies over real-world city driving cycles at different cold ambient temperatures. The data confirmed average fuel savings of 14.5% and 4.7% achieved by eco-driving and eco-heating, respectively, offering a combined energy saving of more than 19% when comparing to the baseline vehicle driven by a human driver with a constant-heating strategy.