It has been said by respected engineers that unlike science, engineering is simply a study of approximation and not a practice in making an object to exact dimensions. That might sound outlandish to anyone who's seen engineers pour over equations to get a result down to a decimal, but engineers only need to design something, be it a bridge or car, to operate within certain parameters. Once it meets those requirements, the job is done. Except thanks to fuel economy restrictions, the bar keeps getting set higher.

The constant changing of the parameters means that new engines and drivetrain technologies need to be invented.

With automakers struggling to meet the demands of a power-loving public and a regulatory system insistent on fuel economy, why not solve the problem by making an engine that can do both instead of designing a motor that sort of meets the demands halfway? Infiniti's latest engine does just this by varying the compression ratio, enabling the cylinders and crankshaft to move and optimize the combustion chamber for either power or efficiency. Stomp on the pedal of the upcoming QX50, the first car that the revolutionary engine is slated for, and the compression ratio lowers to provide the full power potential. Flick the cruise control switch and suddenly compression ratio goes up to leave some gas for later.