Space utilisation is very important in HEVs due to the densely populated engine compartment, and this poses considerable challenges for the designer.
Machines must be able to withstand the harsh underbonnet environment where extreme temperatures, corrosive fluids and high shock loads are commonplace. Additionally, to minimise the powertrain extension, an abnormally thin, large diameter, machine may be required which can lead to conflicting demands. For example, it could serve as starter motor, traction motor and generator, and therefore must be capable of an extremely wide speed range.
For EMX, these challenges require highly sophisticated designs using technologies previously unseen in automotive engineering.