Nissan’s Infiniti division is the first company to release a production car engine with Variable Compression-Turbocharged (VC-T) technology. This technology took them more than two decades to perfect, and the result is a high performance engine offering that claims to offer vastly increased fuel efficiency as well.
By changing the stroke length, the engine can infinitely vary its compression ratio between 8:1 and 14:1. When the engine’s control logic electronics think you need more power, the actuator arm works on a control shaft to change the position of a multi-link pivoting around the connecting rod’s main bearing, lowering the piston in the cylinder. This decreases the compression ratio, allowing the turbocharger to produce more boost without the risk of pinging or detonation. But when you’re just cruising in top gear, the system will do the exact opposite, going for the highest possible compression to improve fuel mileage.
Infiniti claims the technology gives the engine “the torque and efficiency of an advanced turbodiesel—without the equivalent emissions”.