By on August 15, 2016

 

INFINITI four-cylinder turbocharged gasoline VC-T engine

Infiniti has a revolutionary new engine in the works that’s both a high-compression mileage-maker and a low-compression pavement burner, giving drivers the option of being lean or mean at any given time.

The world’s first variable compression engine, dubbed the VC-T, ate up 20 years of design work before Infiniti went public with its achievement. The automaker plans to unveil the revolutionary engine next month, at the Paris Auto Show.

VC-T (Variable Compression-Turbocharged) is two engines in one. The 2.0-liter turbocharged mill is able to change both its compression and its displacement at will, depending on the type of driving required.

INFINITI four-cylinder turbocharged gasoline VC-T engine

The VC-T’s Jekyll and Hyde personality is the latest leap forward in gasoline engine efficiency and powerplant versatility. By raising and lowering the height of the pistons’ reach, the engine allows for low-compression (8:1) cruising under light loads, and high-compression (14:1) performance.

“It is a revolutionary next-step in optimizing the efficiency of the internal combustion engine,” said Infiniti president Roland Krueger in a statement. “This technological breakthrough delivers the power of a high-performance 2.0-liter turbo gasoline engine with a high level of efficiency at the same time.”

Infinity claims the technology improves fuel economy, lowers noise and vibration levels, and allows for a smaller, lighter engine.

Performance specifications and mileage estimates should drop at the engine’s September 29 unveiling, but rumors about the mill’s output already abound. Several media sources put the VC-T’s power between 265 and 270 horsepower. Expect to see the new engine offered in the 2018 QX50.

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54 Comments on “Infiniti’s Variable Compression Engine is the Chameleon the World Wants...”


  • avatar
    azulR

    The first variable compression engine? Just google “Saab variable compression engine”. Infiniti’s may well be more sophisticated but hardly the first.

    • 0 avatar
      InterstateNomad

      I believe that the SkyActiv engine, although not variable compression, can switch between modes depending on usage (I believe it involves a modified Atkinson cycle, but I’m not knowlegdeable enough to say more). I’m sure you have to ask marketing to create hype, no matter who else has done it before.

      • 0 avatar
        redav

        They use adjustable valve timing to change the effective compression ratio. The valve stays open as the compression cycle starts which means the cylinder sees less total compression.

        They call their engines “Miller cycle” rather than Atkinson, but in situations it mimics the Atkinson.

      • 0 avatar
        car driver

        nissan 1.2 dig-S run in both miller and atkinson cycle so nissan have done that from 2010, this is completely different, the engine does that too, but it also change compression and it sometime run in hCCI mode.Mazda engine is a fix compression.

    • 0 avatar
      danio3834

      I was going to say this as well. IIRC SAAB’s design used some sort of variable height head gasket contraption. The technical details are hazy to me but I remember a drawing from maybe 10-15 years ago.

    • 0 avatar
      carlisimo

      It was never finished or used, was it?

      • 0 avatar
        heavy handle

        The Saab VC engine was used as a development testbed, but not as a production engine.
        It allowed them to test a huge number of compression/boost combinations, something that would have been much more expensive if they used fixed-compression engines.

    • 0 avatar
      L'avventura

      Variable compression engines (VCR) has been around for over 100 years in concepts and prototypes.

      Harry Ricardo (famed engine designer; designed the Rolls-Royce Merlin, etc) had builtthe E-35 variable compression ratio engine back in the 1910s for the Shell Company, which was crucial to the octane number rating system being developed.

      SAAB, Peugeot-Citroën, etc who have since shown VCR engines have never actually brought it to market. Given how old ICE are someone has likely thought of and built it decades earlier. Such is the case with seemingly modern engine developments like gasoline direct-injection, BEVs, hybrids, etc.

      If Infiniti-Nissan is actually able tobring it to market then they will really be the first. It would be a huge accomplishment.

    • 0 avatar
      car driver

      Nissan have patent dated back to 1991 and test engine dated back to 1998,and several test engine at SAE, SAAB was the first to make their own public, but it does not mean they were actually first, to calaim who was first is difficult to say.

    • 0 avatar
      car driver

      nissan have been working aon VCR from 1991

  • avatar
    TrailerTrash

    The death reports of the ICE were indeed premature.

    Ya gotta love the free world and the economics and competition of profit. This is wonderful, if true.

    When will we be seeing any advancements in battery development?

    • 0 avatar
      mcs

      Wait’ll these things are out on the market a while and people start to put a few miles on them before you start celebrating.

      As far as battery advancements and other EV improvements go, they’ve been moving out of the labs and into production. It takes a few years to get a technology from lab to mass production. In a few years we’ve moved from 80-mile range low-end EVs to 200+ miles for the same money. At the high end, the P100D is rated 380 miles range for the European cycle. Nissan has shown a solid-oxide fuel cell range extender that runs on ethanol and it’s been running around Rio during the Olympics. Personally, I have a battery in my EV that has 34k miles on it without a noticeable loss in range (showing 115 miles on the range meter at this very moment), so they are making progress on degradation. I have close contacts in battery labs with technology that improves density, increases electrode life, drops weight, and has a shorter less costly manufacturing process. It’s moving from the lab towards mass production. They expect to be in mass production in 2020 – hey, it takes a while.

      So, there has been steady progress in batteries, it’s just that you have to read tech publications to hear about it. This Nissan engine kind of follows my theory that the EV won’t kill the ICE. The ICE will commit suicide via the escalating complexity of engines and transmissions. Hey, who wants to be the first to buy one of these and keep it past the warranty period?

      • 0 avatar
        VoGo

        Summary: battery efficiency has doubled in 5 years, while ICE improvements are about 20%.

        Why do so few of the B&B see a trend here?

        • 0 avatar
          jkross22

          ICE improvements are totaling 20% in the last 5 years? Where’d you find that info? I would’ve guessed 9% with DI and small engine turbo charging.

          I’m not sure anyone’s doubting the electric car trend. It’s the range that still presents issues for most people, especially when mass market real world range doesn’t come close to manufacturers’ claims.

          My experience with the i3 bore this out. Claimed range is 81 miles. I got 58 and I wasn’t driving it like I robbed a bank.

          • 0 avatar
            TrailerTrash

            well…I am doubting the trend, unless you and VoGo like to call such miniscule EV sales percentage in the marketplace advancement. That is not a trend. It’s closer to cultish.

            And this is kinda another of those false stat manipulations. Like when Mazda growth percentage at 15 percent is looking larger than Ford’s 1 percent. Any improvement over little is big.

            and I am sayin this as somebody who is looking forward to the hybrid growth in cars, especially the Pacifica. I am really looking forward to the 30 mile plus range of this minivan since moving into a minivan is required for us old people. Dressing poorly and bigger cars is simply part of the dying process.
            I just don’t like all electric nor do I like the forced popularity/funding of it. But that’s just me being a cranky old person.

        • 0 avatar
          TrailerTrash

          well…I am doubting the trend, unless you and VoGo like to call such miniscule EV sales percentage in the marketplace advancement. That is not a trend. It’s closer to cultish.

          And this is kinda another of those false stat manipulations. Like when Mazda growth percentage at 15 percent is looking larger than Ford’s 1 percent. Any improvement over little is big.

          and I am sayin this as somebody who is looking forward to the hybrid growth in cars, especially the Pacifica. I am really looking forward to the 30 mile plus range of this minivan since moving into a minivan is required for us old people. Dressing poorly and bigger cars is simply part of the dying process.
          I just don’t like all electric nor do I like the forced popularity/funding of it. But that’s just me being a cranky old person.

          • 0 avatar
            VoGo

            TT,
            I am talking about the trend that battery efficiency is improving rapidly. Within 5 years, it should be at parity with ICE.

            Sales will follow once the technology is there.

          • 0 avatar
            TrailerTrash

            VoGo
            I understood perfectly what you were talking about.
            And I still say it s much to do about nuthin.
            Perhaps one day it will be transforming.
            But right now what you are trying to imply that all things are equal.
            They aren’t.
            The ICE has been around for a long time. It has perhaps reached a point of slow gains for advancement, but the advancement and impact and pillar of our economics lives is impossible to measure against the EV.
            Not even measurable.It has about the same amount of influence on our world as my vote does.

            I hope it does become an electronic world ONCE we even have a plan for providing the electricity. Right now we are not even close. Forget about solar and wind power.
            IF we make great advancement in electric power production and delivery, and the EV becomes useable, everything will be terrific.

            Not now.

          • 0 avatar
            TrailerTrash

            VoGo…
            not to off on a side track…but all this is really weird.
            The more economic we make cars…the more trouble we bring.
            It reminds me of the lines in Gone With The Wind. Tracy is explaining how if we build airplanes, we fill the skies with smoke. We make telephones, the world loses distance., etc. Something like that….
            And the more economical we make driving, the more people spread out. The more farm land we lose to developments.
            The more advancements in medicine, the longer we live and the more over crowded the planet gets and the less resources are had.
            The internet brought fantastic freedom of research, yet we never see each other face to face anymore. Our cell phones, although they have made up constantly available and in touch, have taken away our solitary time and are our altars, our daily holy books.

            Its like we are all on the train to destruction.

        • 0 avatar
          DevilsRotary86

          I have to admit, my lack of enthusiasm for battery vehicles is mostly due to the fact that there isn’t a battery vehicle out that I would actually want to pay money for.

          You are right about electrics catching up with ICE eventually. I just don’t care. Now if there was an electric car I would be excited to pay money for I would be more interested. But there isn’t.

          • 0 avatar
            jimbob457

            ICE and EV’s are both very mature technologies. IMO a five year trend is not very important. I suspect that EV’s will ultimately win in the end, but with $50 oil as far as the eye can see it may be decades.

  • avatar
    redliner

    Im confused… I thought low compression is bad for efficiency (but easier for emissions compliance). Isn’t that why Mazda’s Skyacvtive engines have such high compression?

    On another note – Holy complicated Batman! It’s like the ultimate Rube Goldberg machine, what with its turbo this, variable valve timing that, and variable displacement variable compression design.

    It is at this point that electric motors are just so much more elegant from an engineering stand point. Now about those batteries…

    • 0 avatar
      danio3834

      This has to be for emissions compliance. Otherwise high compression would be desirable for better economy and power…and most emissions. The side effect is higher oxides of nitrogen which of course is the barrier that modern diesels are running into.

    • 0 avatar
      wmba

      Because Willems cannot read the diagram, and neither did you. He got it exactly backwards, much like he doesn’t seem to understand that the VW TDI has nitrogen dioxide problems NOx, not nitrous oxide N2O problems. The latter has been mentioned, ooh, about a million times in articles all over the world, but Willems hasn’t grasped the concept.

      • 0 avatar
        Kenmore

        Woomba’s back!

        Hey, I’ve got a nice, big Donald Duck coffee mug that says “Cranky to the Last Drop”. Not using it, trade you for some red Solo cups?

        • 0 avatar
          wmba

          I tried to leave, dear Fridge, but Mark wouldn’t delete my account – no matter the computer, tablet or phone, the WordPress home page sits there stunned. It wouldn’t even change my email address after seven years of continual trying. You type in the new one and the thing sits there.

          Still, I must say as a septuagenarian curmudgeon, this place is about as technically sound as the local vaccuum store.

          The question you ask below about vibration is handled by the link that changes the stroke – forces can be balanced against the piston/rod. Probably the engine doesn’t even need a balance shaft that all the other 2 litre turbos have.

          Hey, I still find your quite clever obervations very amusing and worthwhile. Just not about me. I’d prefer to be gone like the wind. So here’s their chance to do what i asked – delete the account.

    • 0 avatar
      heavy handle

      It’s using high compression for efficiency, and low compression for power, presumably with lots of turbo boost.

      It would be great to read a technical report on this engine. At first glance, it doesn’t seem overwhelming at only 270 HP. Even Volvo gets more than that out of a 2.0-liter. Maybe the efficiency is outstanding.

      • 0 avatar
        Big Al from Oz

        heavy handle,
        I would assume from off idle, there is not turbo boost, so there must be some form of bypass for the intake. As rpm rises exhaust is bleed off (metered) to the turbo and intake air diverted to the turbo until the turbo comes gradually on line.

        This way the engine can run at low rpms, with high torque, good FE and no turbo lag.

        This seems to be a fantastic idea.

        This is an assumption on my part

    • 0 avatar
      car driver

      This is a turbo engine also, so it switch from turbo boost toma none tubo boost, at boost it runs at 8:1, which turbo engines are more efficient, at 14:1 there will be no turbo.

  • avatar
    Kenmore

    How does replacing a simple connecting rod with an articulated linkage make for lower noise and vibration levels? Contraptiony much?

  • avatar
    indi500fan

    Here’s some example of 100 years of variable compression engines:
    http://www.nap.edu/read/21744/chapter/27

  • avatar
    ajla

    “Several media sources put the VC-T’s power between 265 and 270 horsepower. Expect to see the new engine offered in the 2018 QX50.”

    The current QX50 makes 325hp, so I’m hoping this will be the base engine and some sort of 300hp-400hp V6 will still be available.

    • 0 avatar
      Waftable Torque

      From what was implied in another article on this engine, this new one will eventually replace all of Nissan’s 3.5L V6’s globally. That would be far more significant news if that was the case.

      • 0 avatar
        Big Al from Oz

        Waffable Torque,
        This is the first of this engine. What is its future potential, say in 5-10 years? Look at the humble V8 power output over the past 20 years.

        I did see some comments allude to the fact this engine isn’t a real advancement over the current breed of turbo fours. But, I’d say this engine will have a huge flat and fat powerband.

  • avatar
    Chocolatedeath

    Wonder how this would do paired with some batteries?

  • avatar
    celebrity208

    I’d be interested in a comparison between this engine design vs the Honda EXLink engine design.

  • avatar
    28-Cars-Later

    Cool stuff, maybe in twenty more years this will be solid enough to go mainstream.

  • avatar
    mfgreen40

    Why do golf cars still have heavy lead acid batteries? Cost?

    • 0 avatar
      Russycle

      Yep. If a cart goes around the course twice in one day, that’s about 10 miles between charges, at about 15 mph. Don’t need fancy batteries for that kind of range.

      • 0 avatar
        DevilsRotary86

        Although a quick google search turned up no less than 3 companies that specialize in selling lead-acid to lithium ion conversion kits for golf carts. So that world may be changing too.

        • 0 avatar
          Lorenzo

          The latest advances from Club Car include a more efficient 48 volt motor for hill climbing, regenerative braking, and a variable charging system to prevent overcharging. Street legal personal carts are usually gas powered, and the motors are now EFI. Some of the electric cart advances cost almost enough to make battery upgrades cost effective, but battery packs that require their own cooling system might have environmental dangers connected to golf course use, fires in particular.

          BTW, more than a few golfers are so lazy they’ll put 10 miles on a cart in one round rather than stay on the cart path and take a few extra steps. Others are so bad at the game they take extended tours of parts of the property that aren’t actually part of the course to retrieve their ball, and many housing development courses have such convoluted routing that the distance from hole to hole makes walking impossible, and adds significant mileage to the round of golf.

  • avatar
    zososoto

    INFINITI denveloped this engine? Not Nissan? I thought infiniti was just a marketing department

    • 0 avatar
      motormouth

      Without looking elsewhere I’ll go along with that. Infiniti will welcome nay kind of marketing boost and Nissan will launch the tech with them to give them a headstart before trickling it down into Nissan-badged products.

      Not to mention Infiniti deal in far smaller volumes, so serves as a good real-world test bed. Far fewer vehicles to fix if this proves to be a reliability bust (could happen).

      • 0 avatar
        Kenmore

        “Far fewer vehicles to fix if this proves to be a reliability bust (could happen).”

        Sandboxing wildly suspect flakiness? That linkage reeks of beer & sauerkraut.

  • avatar
    sportyaccordy

    My inner geek is screaming with glee

    My inner pragmatist is likening this to the toilet machine from the Simpsons Australia episode.

    People dump on the Prius, but you scale that thing’s powertrain up and you get the RX350h, which makes more power/torque than this thing and by Nissan’s own estimates still gets significantly better gas mileage for what I imagine is much less cost.

    Someone needs to answer the question of why manufacturers are rushing to turbos when hybrids are the clearly superior solution.

    • 0 avatar
      Snail Kite

      This is still way cheaper than adding a battery, motor, all of the electronic hardware to control them. Plus there are no design compromises from having a big battery.

      This may be new, but 4 cylinder engines have added valve control, balance shafts, direct injection, and turbocharging and still remained economical. I don’t see why this would be any different.

      • 0 avatar
        ajla

        Is this thing going to be faster or more efficient than the current Infiniti hybrid offerings (which use an older system in the first place)?

        Infiniti is still ostensibly a “luxury” brand so it would be nice if they didn’t just settle for “it’s way cheaper”. I don’t think the best solution for an Altima SL should be the same for the Q50.

  • avatar
    CoolCreek

    I wince at the picture thinking the mechanism will break.

    And turbo chargers offer variable compression as needed.

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