A “Mini-Hybrid” Transit Bus with Electrified Cooling System

A Diesel engine-powered transit bus was fitted with a powertrain thermal management system comprised of electrified components, including fans, coolant pump, and electronic thermostat. A high output belt-driven 24 volt DC alternator was installed to provide power for this system in addition to the normal bus electrical power loads. Except for the alternator, all components were mounted on a slide-mounted tray to facilitate service and maintenance.

In practice, this “mini-hybrid” vehicle has demonstrated a fuel economy improvement of 10.5% in fleet operation during a four month period and is expected to achieve 5-7% better fuel economy annually, compared to a conventional bus. Additional benefits include lower maintenance costs, improved safety, and enhanced serviceability.