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Wow, wait till aftermarket ECU tuners get their hands on that and can play with variable compression from 7.0:1 to 18.0:1. On top of varying fuel and boost already.

I wonder why they're using the whole separate rod and piston driven off the crank to control the compression instead of an electric device with a rod and piston driven off that. Maybe it makes too much mess around/external to the head

They indicated it was a 100% mechanical setup so thats probably why. I wonder what they use to move the actuator that adjusts compression. That is one awesome technology. Now if they can make it strong enough to handle some real power!

didnt play the you tube vid as this computer seems to get viruses from you tube all the time ,VCR is old technology . . was reading about an old test engine used in TAFE,. . . .they could raise the compression of the engine by lifting the head closer/further away from the pistons, not sure how they did it but it was within the grasp of first year students

this is true ^^, if this engine design makes it into regular production cars it will be interesting to see how durable it is compared to the current crop of engines, good to see some new devolopement coming out as there doesnt seem to be a lot going on with manufacturers (apart from hybrid tech) lately

that is neat. the end of it though makes things more interesting as they mention VVT and forced induction. overall someone had a bright idea to make an engine more efficient. that certainly does that. also like the comparison vs hybrid.

Not really a new concept, Saab did this in 2000 and unveiled a motor that had a tilting head which varies the CR. Haven't heard anything since then.

The geared conrod method is different, Saab probably patented the tilting head.

Wonder how the intrinsic strength of both solutions stacks up...

Not really a new concept, Saab did this in 2000 and unveiled a motor that had a tilting head which varies the CR. Haven't heard anything since then.

The geared conrod method is different, Saab probably patented the tilting head.

Wonder how the intrinsic strength of both solutions stacks up...

it would be good if it was out soon on cars, you would be able to have the ecu read the octane of the fuel in the tank and adjust the CR too suit , , ,run anything from cats piss ULP to E85 (and anything in between)without having to lift a finger

  • 3 weeks later...

Nissan's version is better if you look at that tiny gear wheel below the piston that has to take alot of force you can tell that's a potential weak point. Plus nissan's version suits a reciprocating motion better.

http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/vcr.html

Yeah it's old technology - another way to do it is to set up the head with high comp ratio and use psid controlled valves to dump pre combustion fuel/air mixture into exhaust. It's wasteful and not good for the environment, plus adds too much plumbing around the engine.

  • 1 month later...

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