Ephrem Chemali

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Recently, increased emissions regulations and a push for less dependence on fossil fuels are factors that have enticed a growth in the market share of alternative energy vehicles. Readily available energy storage systems (ESSs) pose a challenge for the mass market penetration of hybrid electric vehicles (HEVs), plug-in HEVs, and EVs. This is mainly due to(More)
A battery-ultracapacitor Hybrid Energy Storage System (HESS) combines the advantages of both Li-ion batteries and ultracapacitors. Li-ion batteries sustain a relatively long electric only driving range but degrade if exposed to high C-rates and large number of cycles. Ultracapacitors are robust, have a quasi infinite cycle life and can sustain highly(More)
Nowadays, the two competing powertrains used in Hybrid and Plug-in Hybrid Electric Vehicles are embodied by the Chevrolet Volt and the Toyota Prius. These powertrain architectures are costly which is primarily due to the fact that they either use a large and expensive battery pack or a smaller battery pack coupled to a power converter. The concept of a(More)
A semi-active hybrid energy storage system, consisting of a Li-ion battery pack, dc/dc converter, and Li-ion capacitor pack is developed for a range extended plug-in vehicle application. The vehicle has a series-parallel drivetrain with two electric motors, a gas engine, gearbox, and a clutch to allow the engine to run decoupled from the gearbox in range(More)
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