Infiniti showed off a slightly updated Q50 yesterday at the Paris Motor Show, but nobody gave a damn because right next to it was this: the first ever production-ready variable compression-ratio engine. Here are some new, highly pornographic photos and additional details on this marvelous piece of machinery.
The big news is that Infiniti’s power goal for its diesel-killing 2.0-liter variable compression turbocharged four-cylinder is 268 horsepower, and the torque target is 287 lb-ft.
We’ve written all about how the new Jesus-engine—called the VC-T—actually works, but here’s a quick refresher video recently released by Infiniti:
And if you’d rather not watch that, here’s the gist: an engine can work most efficiently at high compression ratios, but sometimes at high engine loads (and high boost), that can yield pre-ignition and knock.
Since Infiniti doesn’t want to pull power to reduce knock when the driver gives it the beans (that kind of defeats the purpose), it created an engine that can vary the compression ratio via a “multi-link” system.
Basically, there’s an electric motor that rotates a cam, which pushes an actuator arm, spinning a “control shaft.” There’s a lower link attached to that control shaft, which gets pushed and pulled when that shaft is spun (presumably because the lower link and the control shaft have off-set axes, just like throws on a connecting rod).
That pushed (or pulled) lower link yanks shoves the multi-link, which rotates about the crankshaft, pulling or pushing the upper-link to change how high the piston goes in the cylinder, thus altering the compression ratio. The piston goes higher in the cylinder (high compression) when the driver is light on the gas, and it’s lower (for lower compression) when the driver is deep on the pedal to reduce the risk of pre-ignition.
The compression ratio can vary from 8:1 all the way up to 14:1, and Infiniti says this yields “an engine that combines the power of a high-performance 2.0-liter turbo gasoline engine with the torque and efficiency of an advanced diesel powertrain.”
Plus, they say, it doesn’t have the negative emissions of the diesel, and the Noise, Vibration and Harshness will be much better than the oil burner. In other words, this thing, under development for more than 20 years and finally set for production in 2018, really is meant to slay diesels.
Here are some new images of Infiniti’s crown jewel :