Assesment of Fuel Economy Improvement Potential for a Hydraulic Hybrid Transit Bus

Abstract

Hybridization, in particular Hydraulic Hybrid Technology (HHT), is offering significant powertrain efficiency breakthroughs in near and mid-term. A data acquisition on a transit bus has been performed to assess the potentials for fuel consumption reduction based on deceleration energy calculations. Initial study suggests fuel economy improvements of 20 % are possible. Additional investigation was carried out to quantify fuel savings that would be achieved by implementing a start-stop system. Significant fuel consumption occurs during bus idling periods at bus stops and traffic lights. Analysis shows that more than 15 % fuel reduction is possible solely by turning off the engine.