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.
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.
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Wow!just when everyone thought ICE has reached its limit, they come out with this.
What kind of spark plug going to be used though? Should be a special one as the variation in the CR is quite large
This tech has actually been developed for decades is not mistaken. Not really surprising given how complicated the cracking system is. To be honest, the idea behind tech seems to be way ahead of it’s time decades back. It was and still is a genuine engineering idea but let down by difficulty in execution. Today, this is rather obsolete given that DI with VVT can virtually allow the engine to have result of variable compression without the need of a complicated crank system. Also, the Atkinson cycle is now proven to be a viable option too.
Renault going to have access to this engine as well?
An engine to have both efficiency (less fuel consume) & powerful (high boost & pickup) by changing the compression ratio to 14:1 (fuel efficient) or 8:1 (power). Nowadays, our car usually compromise power for fuel efficiency but for this Variable Compression Engine, we can have both (fuel efficiency & power) depends on situation and the way we drive our car.
Proton Campro.
Oil quality is going to be critical to the engine
They should seriously be awarded the engine of the year. Bravo Infiniity !!
After watching it a few times, I don’t think there us actually any change in displacement, since the total swept volume remains the same.
It just moves the pivot point of the main conrod and thus the TDC position.
Yes, I’m nitpicking.
And yes, this would be ground braking.
You can slap on a pretty big turbocharger for big torque and when coupled with an electric motor, you get a good kick at low RPM as well.
Limited to benzine (petrol) version engine due to current technology constraints.
Diesel variant is impossible….
crankshaft & linkage failure
lubricant oil leakage
electric motor seized
overheating
Kaput!
This means it runs on high compression ratio
for city driving, which puts further strain on cooling system in an already hot condition.
this is how i see it:
a) highway driving, highest CR possible (14:1).
b) mixed driving, somewhere in between depending on load on the engine.
c) urban driving (stop/go), lowest CR possible (8:1).
i could be wrong but i figure thats how infiniti is going to utilise their variable cr turbopetrol engine.
Low compression 8:1 is associated with engine with high pressure turbocharges while high compression 14:1 associated with N/A engine works without turbo. So high compression was intended for urban use where most of the time turbocharger will not spool when low compression is during highway driving when turbocharger get spool at most of time.
Get your research correct before commenting.
Actually it’s the other way around. Youd know what you typed is rubbish if you have ever driven a turbo car before.
At highway cruising speeds the engine is working in vacuum. Yes. Like an NA. Likewise at low engine speeds…ie in city use.
The correct description will be the compression (static)/boost (dynamic) will vary based on Engine LOAD. Irregardless of highway or city use. But you will actually see more compressor utilisation in actual urban use instead of highway…when you accelerate for example.
When you floor the throttle this engine will drop the compression ratio to run higher boost and more advanced ignition timing than otherwise possible if running high compression. The power comes from not only the boost..but also ignition timing…where it can hit as high as 40degrees BTDC.
Campro is the best…..Asian BMW
ICE is as good as dead when Tesla Model 3 rolls out in 2018. When the cost of battery price drops by another half and double the efficiency, all oil producing countries and traditional car makers will be in trouble. Welcome to the future now.
oil producing countries will block electric cars but will pretend to support. petroleum is here to stay. ICE ICE baby.
I would say the video did a good job in illustrating how a sprinter & marathoner merge to create a perfect engine.
Is this a pioneering new VC-Turbo Power-train !? That is debatable.
The old school of Variable valve timing which increases an engine’s flexibility under different conditions, have taken care or resulted in increased fuel economy & better performance.
If Infinity is talking of outright power, they are far behind the Germans which produce 400BHP for a 2 liter engine.
Variable compression together with Direct Injection & turbo charging are less complicated without an extra actuator arm to be operated by an electric motor fitted on the outside of the engine block.
What happen when the actuator is not working or due to electrical failure ?!
My point is Hybrid or Full Electric is the way forward. Car manufacturer should concentrate on developing cars that is more environment friendly.