"New technologies and design concepts had to be combined in a synergistic way so that every gain was multiplied by another. Technology, per se, is not the answer, it's how intelligently you use the technology that gets you there," York says.
The first step in Precept's design was a shape with as low as co-efficient of drag as possible. After research that lasted 10 months and ended in September, 1998, GM designers came up with "the most aerodynamic 5-passenger sedan ever created."
To be specific, Precept has a coefficient of drag of only 0.163, which is about half that of a regular family sedan and lower than the reigning record holder about production vehicles, the EV1 and its Cd of 0.19.
George Claypole, a GM Advanced Technology Vehicles vehicle integration engineer, says that "typically aerodynamic improvements are the result of tremendous attention to detail: every shape, every surface, a thousand tiny steps."
But four key architectural concepts are at the heart of the Precept's remarkable coefficient of drag: rear engine layout, a rear thermal system, electronic rear vision (i.e. no outside mirrors), and a smooth underbody flow.
Driving this airfoil or wing shape is an electric traction system (ETS) in the front and a heat engine traction system in the rear, both of which are controlled by the hybrid control system.Precept's propulsion system manager, Mark Kosowski, explains that "engineers call the device that powers the front wheels a 'drive unit' because it combines an electric motor, a single-staged planetary-gear reduction unit, and a differential in one compact assembly."