FEV, KSPG Tout Latest EV Range-Extender System

Powertrain engineering firm FEV GmbH and supplier KSPG say their compact range-extender system for electric vehicles can fit under the rear floor of most production cars.

The two German companies continue to develop the technology, which they showed in prototype form in October at the IAA convention in Frankfurt and last month at the SAE World Congress in Detroit. The system currently is being demonstrated in an electrified Fiat 500 city car. Gary Rogers, CEO of FEV's U.S. unit, tells AutoTech Daily the companies are negotiating with an unidentified subcompact carmaker to mass-produce the system.

Core to the latest range extender is an 800-cc, V-2 gasoline engine that makes about 40 hp. The little powerplant runs a pair of generators through a gear wheel drive to produce as much as 30 kW. The 134-lb system is intended to feed energy into an EV's battery, thus extending the vehicle's range.

Rogers says the system is designed to begin replenishing the vehicle's battery well before the battery is depleted. The extender lacks enough output to maintain vehicle performance if the primary-drive battery is completely drained, but it could provide a reduced-power "limp home" capability under that circumstance.

FEV and KSPG tout their technology as a relatively simple approach to range extension because there is no mechanical connection between the system's engine and the vehicle's wheels. FEV has experimented with range extenders powered by fuel cells, one- and two-piston engines and Wankel rotary powerplants.

Rogers says REV has been able to eliminate about 95% of the inherent vibration of the current system's two-cylinder powerplant by deliberately unbalancing such components as the alternator and water pump. The resulting harmonics, he says, act much like an engine balance shaft but without additional weight or complexity.