VEHICLE PROPULSION SYSTEMS WITH HYDRAULIC ENERGY-STORAGE - A LITERATURE SURVEY

A worldwide literature survey was performed to investigate the status of hydraulic-accumulator-based hybrid propulsion systems. This article reviews the hybrid concept, its benefits and drawbacks as compared with a conventional propulsion system, and the three main hybrid system configurations. Results of major simulation studies on hydraulic hybrid systems are reported for passenger cars, trucks and buses. Hydraulic hybrid vehicles currently under development or in operation are reviewed and experimental fuel economy and performance results are reported. Actual fuel economy data obtained with hybrid buses have generally confirmed simulation results, but little confirming passenger car data was found. The power assist appears to be the most promising configuration for passenger car application.