New Infiniti engine offers variable compression

Discussion in 'The Bench' started by Brian Albrecht, Sep 10, 2019.

  1. GraySky

    GraySky Well-Known Member

    I'm sure, but don't you think they had much less of a grasp on things back then? To meet emissions in the 70's, they dropped compression through the floor, which killed efficiency. Totally the wrong move. All of the steps they took made efficiency worse. I think there is much more understanding now about the combustion process now. For example, look at some of the newer Mazda Skyactiv engines operating at super high compression ratios.
    Hey, you could be right, no doubt. But, I believe that we've got a much better understanding of the basics and are now just milking the remaining gains, which have diminishing returns.
    It will be interesting to see where they find the gains. The real stop to development will probably be when battery technology comes of age and everything goes electric.
  2. John Codman

    John Codman Platinum Level Contributor

    I remember Detroit telling the Feds that the new emission controls were unobtainable with the technology of the day. Honda then told the government that it could meet the new standards. Needless to say, Detroit found a way to meet the standards too. Eventually the piston engine will all but disappear as new technology arises, but it ain't dead yet, nor do I expect it to be for many years to come.
    Houmark likes this.
  3. Houmark

    Houmark Well-Known Member

    I agree..

    The stuff you put inside the engine, fuel and air, has it limits.. A lot, if not the majoritet, of the energy released upon combustion, will be lost in heat and driving the cooling system..

    I read somewhere that s gasoline car, maximum uses 33% of the energy, obtained of the combustions, to power the cars movement.. And in that's without loss in transmission etc.. Lowest calculated was 16%..
    GraySky likes this.
  4. Rob Ross

    Rob Ross Well-Known Member

    It's because the octane is fixed. You can run high compression at the lighter loads to avoid PI and increase efficiency. But at WOP (wide open pedal) there isn't enough octane to support the higher CR.
    bhambulldog likes this.
  5. bw1339

    bw1339 Well-Known Member

    This guy has a lot of great videos on WWII forced induction and octane ratings.

  6. Mark Demko

    Mark Demko Well-Known Member

    We should push TA Performance to develope something like this for the 350:cool::D
    alvareracing likes this.
  7. alvareracing

    alvareracing Well-Known Member

    Mark, could you imagine having direct injection heads for the 350. Talking about gas mileage and performance! I'll never forget when our 72 conv GS with a 200R4 got 22 mpg on Power Tour. I was tickle to death!
    Mark Demko likes this.
  8. GraySky

    GraySky Well-Known Member

    That's why most of the recent development has revolved around the Atkinson cycle engine. Varying the dynamic compression (and now the mechanical compression) is the means to run super lean mixtures and control the temperature with automatic EGR due to cam overlap. It's all about addressing the heat loss issues from here on out, I believe. I bet there will be advances in materials and coatings to help with that. You would think they would design an exclusively E85 burning engine to maximize on the octane and heat-absorbing properties of the alcohol.
  9. Duane

    Duane Member

    I saw a car once that had both a variable compression ratio and a variable spark plug gap.

    It came into the shop as a "problem child" that a bunch of other shops could not fix.

    What happened was the ceramic part of a spark plug had come loose from the metal threaded piece. Often it would stay together, but sometimes the center of the plug would slide out about a 1/2" on the compression stroke. Then the car would run on 7 cylinders.

    We found the problem by watching it run with the hood open. It was the funniest thing, watching that plug slide in and out.
    Brian Albrecht and Mark Demko like this.
  10. bhambulldog

    bhambulldog 1955 76-RoadmasterRiviera

    dynaflow and Mark Demko like this.
  11. Mark Demko

    Mark Demko Well-Known Member

    I remember my dads ‘52 Evinrude FastTwin outboard had that, to go faster you just cranked in more timing
    bhambulldog likes this.
  12. bw1339

    bw1339 Well-Known Member

    All joking aside, I bet that 95 years ago, when the modern distributor appeared, there were people who complained that taking away that lever ruined the driving experience. And front brakes! Fuggedaboutit!! :eek:
  13. Brian Albrecht

    Brian Albrecht Gold Level Monkey

    Read about Ford model T starting
    bhambulldog likes this.
  14. bhambulldog

    bhambulldog 1955 76-RoadmasterRiviera

    I'm very familiar with steering column mounted spark control. I've logged many starts and many miles in Ford model 'A's
    Brian Albrecht likes this.
  15. Brian Albrecht

    Brian Albrecht Gold Level Monkey

    Atkinson engine=no carbs

    I crank myself up ;)
    1972Mach1, Mike B in SC and GraySky like this.
  16. GraySky

    GraySky Well-Known Member

    gotta respect a good pun.
  17. dynaflow

    dynaflow shiftless...

    ...just when we thought engineers had done all they could with inline 4 cyl 4 strokes...not only variable compression, but rod angle and 2nd order harmonics. Wow. Time will tell if others think gains warrant complexity...

    ...started with his methanol vid and became a fan... for "advance lever," my BSA A10 had one. One quickly learns its purpose/value...:eek:
  18. John Codman

    John Codman Platinum Level Contributor

    The problem with any fuel containing alcohol is that alcohol (Ethanol) contains far less energy then gasoline. Gasoline has 114,000 BTUs of energy per gallon, the corresponding number for Ethanol is 76.100 BTUs. The engine will require almost twice the amount of Ethanol to produce the same amount of energy as an equal amount of gasoline. Translation: The more Ethanol in the gasoline mix, the worse the fuel economy.
    Last edited: Sep 13, 2019 at 12:11 PM
  19. GraySky

    GraySky Well-Known Member

    Yes, true. I actually ran ethanol in my Silverado for a while, just to see what the deal was (flex fuel silverado 5.3). It was more expensive due to the mileage difference... ran really well, and cleaned out a lot of junk from the motor. I think ethanol as it stands today is a loser (except for cheap race fuel). It is net loss fuel- requires more energy in the process to make it than it generates. I wish the government would stay out of subsidizing energy when they have no real understanding of the issues, but here we are. The farmers are loving the subsidies. I think it's unethical to use good growing land for fuel production when there are hungry people in the world.
  20. BennyK81

    BennyK81 Well-Known Member

    The goal is to reduce combustion temperature to lower NOx (nitrogen oxides) Emissions.
    VW is now running the Miller Cycle and not the Atkinson (like a lot of japanese cars). And EVERYTHING they do is because they have to lower emissions. All new Gasoline engines come with particle filters like diesels. They have controlled variable oil pressure to reduce load to the engine. newest oil we have is 0w20 and it feels like water when hot.
    Goal is to reach the WLTP 2 standards for CO2. Because if you do not all the car makes get heavily fined.

    most engines we have now do have oil squirters inside to cool down they even added a valve to shut the oil passage off if it is not needed to cool so there is less load on the oil pump.

    lots of crazy stuff...
    Mark Demko likes this.

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