Mazda Announces It Has Solved Gasoline’s Pre-ignition Problem with High Compression

Discussion in 'In the News' started by xcel, Aug 8, 2017.

  1. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    The reported Thermodynamic Efficiency of the new SKYACTIV-X ICE is up to 42 percent with a much larger power range than the current 4th gen Prius' I4. Do not ask how I came about this information. ;)

    Wayne
     
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  2. Jay

    Jay Well-Known Member

    Thanks Wayne. The latest Irvine Skyactiv x press conference has unleashed a flurry of reports that shed more light on the engine. Most of the reports derive from the presentations by Dave Coleman and Jay Chen. MotorTV recently posted videos of the conference (which nobody but rabid Mazda fans should watch :)) so now we can go straight to the source. In the first video, Dave Coleman reviews Skyactiv G technologies while Jay Chen extols the benefits of lean combustion and delves into Skyactiv X details in the second. Some takeaways:

    1. They reiterate that Skyactiv X will be a mild hybrid (possibly i-eloop?).
    2. The engine achieves high efficiency over a broad range of loads and rpms --so much so that they are shortening the final drive ratios significantly. They figure why not improve throttle response if it doesn't cost much in fuel economy.
    3. SPCCI operates at lambdas of 2 to 2.5 (lambda = stoichiometric = 14.7:1 air-to-fuel ratio)
    4. The "high availability fuel supply" (roots supercharger) is not so much for performance increase but to deliver the air needed for lean combustion.


     
    Last edited: Feb 20, 2018
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  3. BillLin

    BillLin MASS: 2018 Bolt EV and 2017 Prime

    Still that 'zoom zoom' company... such a waste. Keep the performance level to not have it feel like those weakling, hyper-efficient hybrids, but close the MPG gap without the added expense of big electric motors and high voltage batteries.

    It will be interesting to see real world comparisons when the time comes. Assuming the hybrid car can approach the 'zoom zoom' of a SKYACTIV-X in some everyday unhurried driving, drive them both in the same way and see how the fuel economy comes out. Will the 42% thermal efficiency and efficiencies in certain modes be enough to topple a hybrid with a 40% thermal efficiency engine? I also hope the SKYACTIV-X engines run cleanly, too. (referring to air quality)

    Edit: I'll watch the videos tonight. Thanks!
     
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  4. Jay

    Jay Well-Known Member

    Bill, I'm skeptical of the short final drive ratios myself. When Jalopnik tested the prototypes last Sept., they posted gas mileage results and the auto gave much better economy than the manual. Why? Evident from the graphs, the taller gearing and lower rpms of the auto was the reason. We'll see.

    Another consideration is cost. Can Mazda keep the price of Skyactiv X competitive esp. with the mild hybrid addition? Honda offers its gas-turbo in all trims of the Civic hatch, even the very low priced LX trim. Will Mazda offer the Skyactiv X in only the top trim level and make customers pay for accessories and do dads they don't want just to get the cool engine?

    At any rate, I'm grateful for the press conferences and that Mazda is marketing and promoting Skyactiv X. Mazda is way ahead of Hyundai and others in explaining to customers the benefits of their wares.
     
    Last edited: Feb 19, 2018
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  5. BillLin

    BillLin MASS: 2018 Bolt EV and 2017 Prime

    I think the mild hybrid (48V) system will be a routine item, like TPMS and rear-view cameras. Not negligible in cost, but a necessary part of every US vehicle. Just like particle filtration will become a fact of life for the gasoline direct-injected cars, barring those particles being oxidized and precipitated through other means.
     
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  6. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    I too am skeptical of the rpm issue. The data below is from my car with a port-injected engine, so it may be different. Still, I see a VERY strong pattern here and would be amazed if they managed to break it. Maybe they can flatten the slope but I doubt they'll eliminate it altogether.

    [​IMG]
     
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  7. Jay

    Jay Well-Known Member

    Another benefit of Skyactiv X, once it's widely adopted by other manufacturers, is that we can drastically lower the octane rating of gasoline and lower the cost. Mazda says that 80 octane gasoline is ideal for SPCCI. Currently, gasoline has to undergo expensive hydrocracking in the refineries and then add expensive additives to prevent combustion ignition. I don't think gas stations will have a Mazda pump of 80 octane just for Mazda, but at some time in the not-too-distant future demand may allow it.
     
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  8. BillLin

    BillLin MASS: 2018 Bolt EV and 2017 Prime

    Invest in the CPU/GPU chips that allow modern engines like the SKYACTIV-X to function. :D (not to mention the autonomous vehicles...)
     
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  9. RedylC94

    RedylC94 Well-Known Member

    Yes. Compared to more conventional engines such as your Fit's, Mazda can "flatten the slope" somewhat because (I assume) they've greatly reduced light-load throttling losses, BUT they can't eliminate the mechanical friction losses associated with needlessly high engine speed.
     
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  10. Jay

    Jay Well-Known Member

    ...or the NVH degradation.
     
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  11. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    Thanks for the embedded YouTubes!

    The small pre-light of a less lean area reminds me of Honda's CVCC engine that ignited a small ball of less lean fuel in a small walled area of the combustion chamber which the flame front expanded out and ignited the large volume lean charge afterwards.

    The Hybrid appears to be a std. 48V system. Probably another $500 to $750 OEM for the larger battery, larger Motor/Generator, harness, inverter, and control. The Roots blower does not appear to be as robust as a std. blower and appears not to have the aggregate losses on the thermo efficiency that a normal one would plus is clutched out except for high power/high RPM conditions so that is good too. Another expense tacked on however.

    The stuff at the end about higher RPM for better instantaneous performance due to not having to downshift concerns me as it does everyone else here. Why add the frictional losses and NVH of higher RPMs?

    The guys that drove the prototypes still say their are stumbles but Mazda is working to remove/reduce it through engine tuning prior to release.

    Finally the Ra Ra about a broader RPM efficiency band than a hybrid to keep TD up is kind of non-sense as the Hybrid MGSet provides power on its own allowing the full hybrid drivetrain engine to maintain its "sweet" low BSFC volume while drivability is maintained. The larger the MGSet, the less reliance on the ICE to provide instantaneous power and that is only getting better.

    I am hopeful but still skeptical until the Mazda3s with SKYACTIV-X reach the road.

    Wayne
     
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  12. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    I have been thinking about this high RPM statement and imho, it is a ruse. Keep the ICE in its power band? I am calling BS as nobody adds pounds of sound deadening to reduce NVH that the new ICE emits unless they had to do it. It is either emissions or they cannot completely control the combustion and power output at lower RPMs. The same problem with HCCI from previous OEM attempts.

    Wayne
     
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  13. Jay

    Jay Well-Known Member

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  14. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    Not far away!

    SKYACTIV-D? 6-years and counting. :)

    Wayne
     
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  15. Jay

    Jay Well-Known Member

    Yep, I know about the US Skyactiv-D no shows. But the Europeans and Aussies should get all engine choices.
     
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  16. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    Just a thought.

    The 2.0L in the all-new Corolla Hatch, the 2.5L in the Camry and Avalon, and the same when hybridized in the Camry, all-new Avalon and all-new Lexus ES, the 1.6L in the Ioniq and 1.4L in the Elantra ECO are on the road or scheduled for the road very soon in the case of the Avalon and ES. All of these engines are 40+ thermodynamically efficient today with little or no driveability issues.

    The all-new variable compression ratio 2.0L I4 in the currently available Infiniti QX50 and soon the 19 Nissan Altima is also "probably" 40+ percent efficient.

    The automotive universe is moving forward with real world products reaching showrooms today or in the near future regardless of what Mazda is doing with the strange sounding power curve of the SKYACTIV-X or the "FOREVER NEVER" SKYACTIV-D media push.

    Wayne
     
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  17. Jay

    Jay Well-Known Member

    Wayne, not to take anything away from those engines but I see them as evolutionary not revolutionary. They don't use a different form of combustion. The Mazda does. The highly atkinsonized engines achieve great efficiency but only over a narrow operating range. Mazda claims great efficiency over a wide operating range which sets their SPCCI engine apart. Anyway, it's a little like arguing how many angels can fit on the head of a pin at this point until we can see the end result in showrooms.

    For me, I have always appreciated the extra effort Mazda's engineers put into making their cars "feel" right. They sweat the details that other makers overlook. Small flaws in power delivery and transmission operation are like a pebble in my shoe. After a few hours it feels like a boulder. I trust Mazda's attention to detail in these areas more so than other manufacturers. Finally, I like the way Mazdas are styled more so than anybody else in Japan right now. The latest MX-5 and CX-5 are gorgeous and I expect no less from this upcoming Mazda3. I'm excited!
     
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  18. SI_Prius

    SI_Prius Well-Known Member

    The new WLTP + real driving emissions (RDE) test cycle in Europe is already pushing manufacturers with DI engine to equip them with gasoline particulate filter (GPF), I wonder how Skyactive-X will cope with more stringent emissions standards.

    PFI engines can comply with stringent emissions without GPF, I wonder if Toyota 2.0 and 2.5 with both DI and PFI will get through emissions in EU without GPF, we will see in couple of months.
     
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  19. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    The SKYACTIV-X solution sounds even more restrictive as they are running 3,000 RPM at standard load to keep "it" in its most efficient zone.

    I want to see everything at 40+ percent. I am not concerned how the OEMs get there, just that they get there.

    Wayne
     
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  20. Jay

    Jay Well-Known Member

    Mazda has confirmed rumors that the next generation Mazda3 will debut at the LA Auto Show at the end of this month. I have not seen any spy photos of the new car but Mazda has released a 15-second "teaser" video (that doesn't show anything) and they've recently released a teaser photo that shows more. We see the Kai concept influence in some of the lines but not much more. The takeaway is that they have an actual car to show in LA in 19 days and presumably they are on track to release the new model next spring. Dave Coleman says that NVH mitigation has been very challenging because of the nature of SPCCI explosions. They are adding a lot of foam under the hood and they had to redesign and strengthen the engine block. Shown in the teaser photo is the sedan model in gray and the hatch in red.

    https://www.carsguide.com.au/car-news/all-new-mazda-3-2019-teased-ahead-of-la-auto-show-debut-71817

    [​IMG]
     
    Last edited: Nov 11, 2018
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