SBIR Phase I: A Compact Home Power Generator using a Free-Piston Engine

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project is to sell affordable backup generators that provide 23 kilowatts, for operating a home's lights and appliances. With power outages due to natural disasters and an aging power grid becoming ever more frequent, and with society increasingly reliant on electricity to power not only lights and household appliances, but also computers, wireless routers, and medical devices, back-up power is an increasingly critical need. This SBIR's portable generator is expected to be more than an order of magnitude lower cubic size and weight, all at a reduced cost compared to existing generators. The broader impact of this project is its significant benefits to the environment by providing backup power at high fuel efficiency (i.e. less consumption of non-renewable fossil fuels) and low emissions of hydrocarbons, particulate matter, carbon monoxide, and smoke. This SBIR Phase I project proposes to address the shortcomings of residential-use backup generators currently on the market. Available backup generators are either small and affordable but can only power a single appliance; or able to power most of a home's needs but cumbersome and expensive. This project will demonstrate the potential for implementing a free-piston internal combustion engine that will maximize fuel efficiency; minimize size; decrease dependence on lubricating oil; and incorporate an engine management system. The objective of the current effort is the engine, while the functioning compact generator will be developed in the next phase. In this free-piston engine design, the two pistons oscillate with forces in balance and reduced side-loads to the pistons, yielding a long-lasting high-speed engine. The pilot work included modification of the cylinder intake ports; addition of a modified squish band and dome to the cylinder head; and use of low-friction bearing materials yielding a successful prototype that runs on regular gasoline. The engineers will continue implementing, testing, and improving on these modifications. The successful completion of this project will yield an efficient, compact, low-weight, and low-emissions generator that produces 23 kilowatts of usable power that runs on standard pump gasoline. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.