Infiniti launches world’s first variable-compression engine

Infiniti has concluded plans to introduce the world’s first variable-compression engine.

Dubbed VC-T for “variable-compression, turbocharged,” Infiniti said in a release earlier in the week that the innovation features a mechanical connecting-rod modification that was first described in a U.S. patent assigned to Nissan in 2003.

The engine, which is expected to be unveiled officially in the upcoming Paris auto show comes with an advanced multi-link system that seamlessly raises and lowers the height the pistons reach within the cylinders, varying the clearance area above the piston and thereby altering the compression ratio between 8.0:1 (at the low point of the mechanism’s travel) to 14.0:1.

Before Infiniti’s announcement, the ability to vary an engine’s compression ratio has been a “holy grail” quest of engine engineers for decades, because “one size” of compression ratio cannot possibly fit all the operating conditions required of a typical internal combustion-powered vehicle.

Saab tried hinging the upper half of the engine in 2000, various other inventors have envisioned racks and pinions to vary the piston position relative to stroke, Lotus suggested a movable piston in the cylinder head to vary the clearance volume, and much more recently FEV demonstrated an eccentric piston-pin that provided two distinct connecting rod lengths (and hence compression ratios) while an outfit called Lugo Developments showed a crazy cammed-crankshaft concept.