Related by context. Frequent words. (Click for all words.) 46 hybrid electric 39 HEV 38 Li ion battery 37 Valence Technology 36 PHEV 36 ultracapacitor 36 propulsion systems 36 inverter 34 internal combustion engines 34 electric propulsion 34 electric motors 33 electric 33 kW 33 Hybrid Electric 33 electric hybrid 32 rechargeable 32 combustion engine 32 ultracapacitors 32 internal combustion engine 32 battery powered 31 PHEVs 31 hybrid 31 electrically powered 31 combustion engines 31 Azure Dynamics 31 hydrogen powered 30 hybrid powertrain 30 Electric Vehicle 30 internal combustion 30 nickel metal hydride 30 acid batteries 30 Electrovaya 30 Ford Escape Hybrid 30 battery packs 30 electric hybrids 30 Chevrolet Volt electric 30 hydrogen 30 rechargeable batteries 29 Chevrolet Volt 29 Hybrid 29 hybrid Prius 29 hydrogen fuel 29 compressed natural 29 Altairnano 28 lithium ion battery 28 LED lighting 28 Lithium ion batteries 28 lithium ion batteries 28 diesel engine 28 lithium ion 28 Alternative Fuels 28 zero emission 28 diesel 28 EV 28 diesel engines 27 photovoltaic solar 27 diesel powered 27 powertrains 27 infotainment systems 27 UTC Power 27 Volt 27 telematics 27 Chevy Volt 27 Fuel Cell 26 Fuel Cells 26 Enova 26 Hydrogenics 26 FuelCell Energy 26 hybrids 26 flex fuel 25 Coulomb Technologies 25 EVs 25 MTI Micro 25 Hydrogen 25 Toyota Prius hybrid 25 alternative fuels 25 Escape Hybrid 25 EV charging 25 diesels 24 bio diesel 24 powertrain 24 Hybrids 23 Ford Transit Connect 23 smart grid 23 tailpipe emissions 22 renewable energy 22 smart fortwo 22 Toyota Prius 22 Electric Vehicles 22 Nissan Leaf 22 Smart Grid 21 i MiEV 21 Clean Cities 21 renewable fuels 21 solar powered 21 Prius 20 Nissan LEAF 20 hydrogen fueling 15 cleaner greener 15 cleaner fuels 13 smart grids