We couldn’t have explained it better, really. The video above is Infiniti’s illustration of its new and groundbreaking VC-Turbo engine, which is the world’s first production-ready variable compression ratio engine. Twenty years in the making, apparently.

The power of a sprinter and the efficiency of a long distance runner – the VC-Turbo combines both, Nissan’s premium brand says. Calling it one of the most advanced internal combustion engines ever created, Infiniti claims the power of a high-performance 2.0 litre turbo petrol engine with the torque and efficiency of an advanced diesel powertrain, without the equivalent emissions.

“The pioneering new VC-Turbo powertrain represents a leap forward for engine development. Vehicle engineers believe the breakthrough in internal combustion technology would come from mastering the variable compression ratio. Infiniti will be the first to bring this technology to the market in 2018. This new generation of powertrains will help our global growth and expansion of the Infiniti product portfolio,” said Roland Krueger, president of Infiniti.

Watch the video above before you continue reading. Done? Here’s what it’s made of, in a nutshell. The VC-T tech allows the engine to raise or lower the height the pistons reach, allowing for the engine’s displacement of the engine to change, and the compression ratio to vary seamlessly between 8:1 (for high performance) and 14:1 (for high efficiency). Brilliantly illustrated by the stance of the sprinter and marathoner in the video.

The switching is accomplished via a mechanical actuator arm that is connected to the piston’s conrods through a slot in the side of the engine block, which is controlled by the engine’s control logic that determines the optimum ratio to be applied depending on the driving demands.

The actuator arm is operated by an electric motor fitted on the outside of the engine block, and pushes a lever-type link that joins the conrods, which themselves are made in two halves. This effectively changes the length of the conrods, where a higher compression ratio is achieved with a longer length, and vice versa.

Infiniti VC-T tech diagram

Click to enlarge

There’s more. The VC-Turbo engine has two parallel fuel injection systems, one direct and one into the intake manifold, and can switch between the standard combustion and fuel-saving Atkinson combustion cycles. The engine can benefit from hybridisation for an estimated further 10% improvement in fuel economy.

The development target power output is around 272 PS (200 kW) and 390 Nm torque. This is good enough to send the 3.5 litre V6 petrol currently used by Nissan and Infiniti into retirement, as the four-cylinder VC-Turbo’s efficiency will be on a different plane altogether. It will be better in NVH terms compared to the V6. Lighter, too.

The 2.0 litre VC-Turbo engine is tipped to power Infiniti’s upcoming QX50 SUV – previewed by the QX Sport Inspiration concept that was revealed earlier this year – before going into the rest of the range. Interesting.