Car Industry

Infiniti's variable-compression engine offers diesel efficiency with petrol power

The company claims it's production ready, but it's not slated to appear in any production car just yet.

Until I get a full-on animation of how the piston stroke is altered on the fly, I'm just going to call it witchcraft.

Infiniti

For the longest time, an engine's compression ratio has been a fixed value, but Infiniti's innovative VC-Turbo is set to change all that.

Using a complicated system of links buried deep within the engine block, it's able to change the piston's stroke, thereby varying compression ratio. It changes the ratio based on a number of inputs, and it picks a suitable ratio on the fly. It's able to change compression between 8.0:1 and 14.0:1.

The benefits are numerous. By running a low compression ratio, the engine's power output can increase, whereas a higher compression ratio can be used for efficiency. Switching between the two can bring both benefits to the same engine. That should help keep the internal combustion engine relevant for a little longer in the face of competition from electrification and hybrid drivetrains.

Infiniti believes the VC-Turbo will produce 27 percent greater fuel efficiency than a similarly capable V6 engine, despite being down two cylinders. The automaker is targeting a power output of 268 horsepower and 288 pound-feet of torque.

At the moment, it's only available as a four-cylinder, so it may not be any use to larger SUVs and vehicles that require a bit more thrust. Regardless, it's a hell of an achievement, even if it seems like a bit of witchcraft, and it will be interesting to see the engine arrive in Infiniti's vehicles in 2018.