The Development of an Ultra Compact Electric Vehicle Range Extender Unit

Range anxiety is the single greatest obstacle to the widespread adoption of electric vehicles
(EV) and the environmental benefits they offer (Fastcoexist, 2013). 44% of UK drivers
consider emissions & environmental friendliness as important factors when buying a car yet
only 5% would consider buying an electric car due to range concerns (ONS, 2014). Vehicle
manufacturers have sought to address this issue through the installation of range extenders.
However, current range extender solutions tend to use piston based internal combustion
engines. The technology is mature, reliable with low maintenance, low fuel consumption &
relatively low emissions. However, there are numerous disadvantages including: significant
vibrations resulting from reciprocating parts (pistons), cost & complexity, relatively low
power to weight ratio, heavy, large footprint and bulky size. Piston engines need engine bays,
and this seriously limits the design freedom with electric vehicles.
Consequently, rotary engines have been considered as an alternative to piston engines because
they have inherent advantages such as high power to weight ratio, compact size, low vibration
(no reciprocating parts), simplicity & low cost. However, rotary engines are also noisy,
inefficient at variable speeds & variable loads, and have high emissions. These factors
therefore present a limitation to the suitability of rotary engines for use as range extenders.
This project seeks to develop a completely novel rotary engine system for use as an ultra
compact range extender for electric vehicles. Our technology aims to eliminate the
disadvantages of rotary engines for range extender applications whilst building on the inherent
advantages. The successful exploitation of the technology will result in cumulative revenue of
£47.5m after 6 years on the market.