Hybrid Propulsion Efficiency Increment through Exhaust Energy Recovery—Part 1: Radial Turbine Modelling and Design

The efficiency of Hybrid Electric Vehicles (HEVs) may be substantially increased if the energy exhaust gases, which do not complete expansion inside cylinder internal combustion engine, is efficiently recovered by means a properly designed turbogenerator and employed for vehicle propulsion; previous studies, carried out same authors this work, showed potential hybrid fuel increment up to 15% employing 20 kW turbine on 100 HP rated power thermal unit. innovative unit here proposed composed supercharged engine endowed with turbogenerator, comprises two fundamental elements: an gas expressly optimized application, suitable electric generator necessary convert into energy, can stored in on-board storage system vehicle. In these parts, realistic evaluated compared traditional turbocharged engine. Part 1, present model prediction dedicated radial turbine, based simple but effective mean-line approach; paper also reports design algorithm, which, owing some assumptions approximations, allows fast determination proper geometry given operating condition. It worth pointing that, being quasi-steady production, considered quite different from ones commonly turbocharging application; reason, consideration required size, such available market, nor has its development been previously scientific literature. 2 paper, defined calculated, algorithm described 1; energetic advantage that could achieved implementation propulsion through performance under conditions As overall result, it was estimated reference turbocompound gain improvement between 3.1% 17.9%, depending output level, while average 10.9% determined whole range.