One of the key variables for an internal combustion engine is its compression ratio. This is the ratio of the maximum volume within the cylinder (when the piston is at bottom dead center) and the minimum volume within the cylinder (when the piston is at top dead center). Obviously, this ratio is fixed at the point of design—the amount of travel of a piston within a cylinder is determined by the profile of the crankshaft and the length of the connecting rod between the two.

At least that has always been the case. But Infiniti plans to change that with the debut of its new VC-T engine which is debuting at next month’s Paris Motor Show.

The higher an engine’s compression ratio is, the more mechanical energy it converts from the combustion of a given amount of fuel mixed with a given amount of air. But too-high a ratio causes knocking—premature detonation of fuel-air mixture during the engine’s compression stroke caused by high cylinder temperatures.