INFINITI Reinvents The Gasoline Engine — VC-Turbo
This could be a huge moment in the automotive world. Infiniti, an automaker not exactly known for leading the way in game-changing innovation, has revealed their groundbreaking new engine design featuring a system that allows on-the-fly combustion ratio changes, something that, as far as I have seen, has never been done.
Most of us have heard of VTec, Honda’s variable valve timing system that helps the engine make more power by swapping to a larger profile cam at high RPM. This is a similar concept, though it’s executed in different way due to the higher stresses seen by the engine crankshaft.
Before we discuss how the system works, let’s look at what exactly the compression ratio is and how it affects the engine’s operation.
To put it very simply – because I only have so much time to sum this up – compression ratio is how tightly the piston squishes the air/fuel mixture during the compression stroke. The higher the ratio, the tighter the squeeze before the mixture is ignited and pushes the piston back down. Higher compression is more efficient while lower ratios offer safer operation by combating knock, or detonation, especially when forced induction is used, which it is on this engine.
The variable compression engine, appropriately named the Infiniti VC-Turbo engine, uses a series of linkages between the connecting rod and the VC system, which is discussed in great detail by our friend Jason from Engineering Explained, who was flown to the Detroit Auto Show by Infiniti to explore the engine and help the masses understand how it works. As usual, Jason does a stellar job of breaking the system down into terms that are easier to understand, using the demo cutaway engine to help illustrate how the system works.
He also dives into some of the other innovations in the engine, which help make it one of the most advanced production engines we’ve ever seen.