Infiniti Has Built A Variable Displacement Engine And It's Spectacularly Clever
The idea of a variable displacement engine is something that’s been around for years. Through cylinder shutdown technology, engines like Bentley’s W12 and Aston Martin’s new 5.2-litre V12 can turn off a whole cylinder bank under certain situations, temporarily giving a smaller, more efficient engine. However, the sort of variable displacement tech Infiniti has come up is way, way more clever.
What the company’s new ‘VC-T’ engine can do is change the stroke of the pistons automatically depending on the driving situation, in the process varying the displacement and compression ratio. The con rods are made of two parts, with an actuator connected to the lower ‘multi-link’ part. An electric motor moves the actuator, raising and lowering the piston height where required.
Using this jolly clever tech, the VC-T can have a compression ratio anywhere from 8:1 for the best performance, to 14:1 for the highest efficiency.
Power-wise we can expect around 270bhp, all while giving what Infiniti claims is diesel-rivalling efficiency. Oh, and apparently it’ll be as smooth as a V6. Those are some lofty claims, so we’re fascinated to see how this thing works in reality.
Expect the engine to replace the company’s 3.5-litre V6, making an appearance in multiple Infiniti vehicles. It’ll make its public debut at the Paris motor show.
Comments
An electric motor on the connecting rod…… jeez i can’t see that being problematic.
In some places you still need topay taxes based on engine capacity
Just another overly complicated device that will break.
But saab was the firts to do a variable cr engine
R.I.P reliability.
If we had that attitude Variable valve timing or VGTs would be non existent
Im ALL for new technology and innovation… but this sounds like it’d be extremely costly in the future when the engine succumbs to basic wear’n’tear
8:1 is not going to be more powerful than 14:1 you infantile pillocks! Less compression means less power….
Until you factor in forced induction
https://turbobygarrett.com/turbobygarrett/compression_ratio_with_boost
That doesn’t make any sense, 8:1 compression will have less power per liter than any equal displacement motor with a higher compression ratio, while a 14:1 compression ratio would be hell on the engine wear wise and preclude things like a turbo charger r
higher compression increases pump losses, on a 2 stroke motor increased compression can make the engine rev less high.
The way i see it, it doesnt “varying the length of the piston stroke” - aka changing the engine displacement. They simply move the crankshaft up and down, changing the compressionratio as they do so. The volume between the piston and the cylinderhead at TDC (top dead center) is the one thing that changes significantly.
Displacement is the travel of the piston times the area, and doesnt not change unless you change the length between the center of the crankshaft and the conrods and i dont see any signs of that.
Just a thought though, havent done any research, what do you guys think?
Pretty sure its variable compression, thats also probably why its called VC-T, Variable Compression Technology I’m guessing!
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