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Mazdas new petrol engine doesn't need spark plugs and is 30% more efficient.

Discussion in 'Science & Technology' started by CAPSLOCKSTUCK, Aug 8, 2017.

  1. CAPSLOCKSTUCK

    CAPSLOCKSTUCK Spaced Out Lunar Tick

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    Its fuel economy potentially matches that of a diesel engine without high emissions of nitrogen oxides or sooty particulates.

    Mazda's engine employs spark plugs under certain conditions, such as at low temperatures, to overcome technical hurdles that have hampered commercialization of the technology.

    HOW IT WORKS
    A homogeneous charge compression ignition (HCCI) engine ignites petrol through compression, eliminating spark plugs.

    Its fuel economy potentially matches that of a diesel engine without high emissions of nitrogen oxides or sooty particulates.

    Mazda's engine employs spark plugs under certain conditions, such as at low temperatures, to overcome technical hurdles that have hampered commercialization of the technology.

    To keep the temperature low at compression, the system reduces the amount of hot exhaust gas inside the combustion chamber.

    [​IMG]

    +3
    To keep the temperature low at compression, the system reduces the amount of hot exhaust gas inside the combustion chamber using a 4-2-1 exhaust system

    In the Skyactiv-G, for example – the predecessor to the Skyactiv-X – Mazda uses a 4-2-1 exhaust system.

    This relies on a pipe with a length over 600mm to elevate actual-use torque, and a loop shape to save space.

    As the long distance cools the exhaust gas before it reaches the catalyst, which would then delay the catalyst’s activation, the system delays ignition timing after engine-start for stable combustion.

    A piston cavity is used to optimize fuel injection further, to formulate a stratified air-fuel mixture around the spark plug, according to Mazda.


    [​IMG]



    http://www.mazda.com/en/innovation/technology/skyactiv/skyactiv-g/
     
  2. GoldenX

    GoldenX

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    As a motor fan, this is great news, but as a rotary fanboy, Mazda, gimme another RX-7 please!
     
  3. therealmeep

    therealmeep

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    So in a nutshell its a diesel engine running on gas with some new fiddly bits to help it with mpg and the works.
     
  4. Melvis

    Melvis

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    so its a diesel engine with extractors that doesn't run on diesel?
     
  5. HD64G

    HD64G

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    Much more complex since it burns petrol (=gas for US). And it has spark plugs for when combustion isn't high enough to induce the burning procedure. The achievement is spectacular, especially for such small company, but Mazda is a rare occassion in motor industry which has given the motor enthusiasts some special cars and technologies in times. Many cudos to them for giving decads of life more in internal combustion engines.
     
  6. Melvis

    Melvis

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    I am guessing the spark plugs kick in when it is at idle RPM when the compression is at its lowest. Mazda is well just Mazda I wouldn't say there anything special but alot better then some other company's, we can thank them for the Rotary engine thats for sure.
     
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  7. FordGT90Concept

    FordGT90Concept "I go fast!1!11!1!"

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    I read an article in truck trend that compression ignition is possible with gasoline but the compression ratios to make it happen are ridiculous. In short, the fuel economy improvements are offset by the weight of the engine to compensate for the high pressures (this is why diesel engines tend to be much heavier than gasoline engines). Increasing fuel economy standards may lead to requiring the development of compression ignition gasoline engines (surprised Mazda is first).

    Wankel engines are kind of crappy though (dirty and inefficient).
     
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  8. GoldenX

    GoldenX

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    Combustion engines in general are dirty and inefficient.
     
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  9. dorsetknob

    dorsetknob "YOUR RMA REQUEST IS CON-REFUSED"

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    Dorset where else eh? >>> Thats ENGLAND<<<
    In the moter trade This is known as Pinking and is Caused by faulty ignition Timing Not Good for Engines as it Damages Pistons
     
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  10. FordGT90Concept

    FordGT90Concept "I go fast!1!11!1!"

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    That's knocking (premature combustion), not compression ignition. Compression ignition engines (largely diesel) use a high pressure fuel injector which forces fuel into the cylinder at maximum compression. The energy from this causes the fuel-air mixture to ignite.
     
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  11. CrAsHnBuRnXp

    CrAsHnBuRnXp

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    Love my Mazda. Hopefully when I trade in my 6, this new engine will be in it.
     
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  12. Brusfantomet

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    That reminds me of the Wärtsilä dual fuel engines. Originally a diesel cycle (burning MDO or just straight crude oil) they could change over to run on natural gas after is was started on MDO. the trick was to use a small pilot injection of MDO at the start of the power stroke and then follow up with natural gas during the rest of the power stroke.
     
  13. HD64G

    HD64G

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    That's why Mazda made it. They are pushing the development of higher compression ratio engines more than any other car manufacturer for a decade now instead of bringing to the market diesel-gate engines or small turbo gasoline ones that irl burn much more fuel than advertised, and now must get bigger and bigger to get lower emissions. Mazda's longtime strategy is proven brilliant now.

    As for Wankel engines, they are also monstrous in output, revving sky-high and sound great. Engines for enthusiasts.
     
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  14. GoldenX

    GoldenX

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    Here in Argentina we still use common engines modified to run on natural compressed gas (with a huge canister on the back), it's way cheaper, very popular with taxis.
     
  15. dorsetknob

    dorsetknob "YOUR RMA REQUEST IS CON-REFUSED"

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    [​IMG]
     
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  16. Totally

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    So they're using performance/race longtube headers, and deliberately inducing combustion through high compression called 'engine knock' when it happens otherwise. Where's the breakthrough?
     
  17. niko084

    niko084

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    I look forward to seeing what it can do but have my doubts/concerns, primarily on reliability and power output.
    --- There are already a number of gasoline/petrol small low power cars available that achieve near the fuel economy of a diesel.

    There are a few problems, greatly increasing compression will increase wear. I'm curious as to what the power band will look like.
    I assume this will also require a high pressure fuel pump on the rail which adds more drawback.
    I believe this will also increase CO emissions (per unit of spent fuel), total emissions maybe down due to increases in efficiency.

    I do not intend to sound like a downer on what sounds like could be a great development to carry over until electric is ready for mass markets.

    ****
    Then the motor head side of my brain boots up and says NO! Blown big block or go home!

    It's not a huge breakthrough per say, they are making the design compatible with unleaded fuels, but nobody else has done so and brought it to large scale automotive production.

    It's a fair bit different from knock, closer related to pre-ignition I suppose.
     
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  18. GreiverBlade

    GreiverBlade

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    actually not Mazda is to thanks for the Rotary ... but rather the Dr. Wankel
    https://en.wikipedia.org/wiki/Felix_Wankel
    controversial history nonetheless ... but like most "innovation/invention" you need a war to draw them out ... sadly.

    and that engine wasn't used firsthand by Mazda
    https://en.wikipedia.org/wiki/NSU_Ro_80
    obviously not the 1st car that used it ... but my grandfather had one
    the 1st one was that one
    https://en.wikipedia.org/wiki/NSU_Spider

    and motorcycle
    https://en.wikipedia.org/wiki/Suzuki_RE5
    ok i should have put Sachs motor or Norton or DKW instead of Suzuki :p

    muh... crappy i wouldn't say ... they had quite some success and fan ... (if you did write "i find the Wankel Engine crappy" i wouldn't quote :laugh: ;) ) dirty? well, which combustion motor isn't dirty... (even the new Mazda Skyactive is still a dirty engine, even if it is more efficient ) efficient? hum, technically no engine is really efficient , but true the Wankel design was too much fuel hungry ...

    it had a nice sound nonetheless ...

     
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  19. Aquinus

    Aquinus Resident Wat-man

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    It's a gasoline/petrol version of a diesel engine with part-time spark plugs for when the engine is cold. Look out Carnot, here we come. :laugh:
    Carnot would be disappointed in the Wankel. Thermal efficiency with that engine is garbage and higher expansion ratios is what lets you approach the maximum possible power out of a heat engine. The wankle produces a lot of power because it revs high, it eat a lot of fuel because it has a poor expansion ratio in terms of the area at the beginning and end of the combustion stroke. The Prius gets good gas mileage because it leaves the intake valve open longer and pushes some air out but, has a high compression ratio if the valve wasn't left open longer. So you have the expansion ratio of basically 14.5:1 so, you get great gas mileage. The electric motor is just to make up for the under-powered engine that's super efficient.

    Diesels are just efficient because you compress the hell out of it until it explodes. They're really heavy engines though.

    Efficiency = Increase in volume at the end of the combustion stroke to bring the ignited charge to atmospheric pressure and temperature. Thank you, Carnot. :love:
     
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  20. FR@NK

    FR@NK

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    Reliability will be the biggest issue as these engine will have even higher piston pressures then diesel engines. If they do make it strong enough then the power to weight ratio will be abit heavy.

    The fuel is injected on the intake stroke so you wont need a high pressure fuel rail. Not to say they wont use one though.

    Injecting oil into the combustion chamber to help seal the "rings" makes it much more dirty compared to most engines.
     
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  21. neatfeatguy

    neatfeatguy

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    I love my 2005 Mazda 3 (especially the lava orange color), how she handles and the zip she has under the hood....but a few things that really pissed me off when about the 50k mile mark was hit. Makes me second guess going with Mazda, but perhaps I'm lucky with my car, she hasn't had too many issues. When I got my car the warranty was only for 36,000 miles. At least warranties today have much improved since I got my car back on 2005.

    First issue around 50k: Purge solenoid valve fail/sticking. Only cost around $20-25 to fix, but still a pain.
    Second issue around 60k: alternator failed
    Third issue around 60k: gunk buildup in throttle body (regardless of regular oil changes and filter changes) - about every 15k since I have to clean it out
    Fourth issue around 75k: thermostat failed
    Fifth issue around 120k: front right wheel bearing failure. It wouldn't really have been much of an issue since it's a normal wear and tear thing, but you need to machine press the knuckle out and back into the new bearing. By the time you buy new parts and find a shop with a machine press, the cost for them to do the work only leaves you around $150 under the cost of having a place do everything it for you. So I had my local Mazda dealership fix it for me.

    I'm at 125k on her now and normal wear and tear issues have cropped up to be fixed (broken rear strut mounts, replacement of rear struts - done around 110k). I need to replace rotors and breaks and if I have the cash I'll replace the front struts, too. Mechanically, under the hood, she's still in pretty good shape. Exterior, with the MN winters she started rusting on the rear wheel wells 3 years ago, regardless of all the washes and turtle waxes I put on her over the years. I suppose she's in pretty good shape for a 12 year old car. Gets me from A to B.

    Only real issue I have when it comes to driving the car is driving in the winter. Even with quality snow-type tires, if there is more than 6 inches of snow on the ground, you're going nowhere if you have to come to a complete stop. I've gotten hung up in my driveway a couple of times when the snow was 6+ inches deep. Since she's pretty low to the ground, compared to a lot of other cars on the road, the big chunks of hard, packed snow that fall off other vehicles that sit in the middle of the road, I have to drive around or they smash into the under body.....I watch every other car in front of me drive right over it like it's not there.

    If I stick with Mazda I'd look at something a bit higher off the ground with similar room/handling, all wheel drive......I'd probably look to a CX-5 or CX-3. Outside of some unforeseen failure on my Mazda 3 hatchback, I figure I'll get another 3-4 years out of her before she's pretty much ran into the ground.
     
  22. Aquinus

    Aquinus Resident Wat-man

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    I'm 2 1/2 years and 55k into my 2015 Subaru Impreza and the only thing that has broke is the power window switch for the drive side window. I considered the Mazda 3 but, I wanted the AWD for the winter. I have the manual transmission which has the 50:50 viscous coupled limited slip center diff which does wonders in the snow. Even with all-seasons, it handles decently in the snow. Like you, I'm no stranger to snow here in NH. The Saab was a nightmare with repairs and in the snow though. I will never go back to front-wheel drive.
     
  23. Melvis

    Melvis

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    Also they dont last very long, high wear rate and use three times as much petrol.

    Yes I know of the NSU having the rotary engine also, but I mean Mazda made it work like it says in the article they fixed some issues with the original design and I guess the rest is history from there onwards. Mazda made the rotary
    successful :)
     
    Last edited: Aug 10, 2017
  24. JC316

    JC316 Knows what makes you tick

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    Detonation is technically compression ignition, just unintentional and not timed. It's also a great way to blow a hole in your piston. It's also a great way to do this to a head gasket. With direct injection coming to gasoline engines, it was only a matter of time before a compression based ignition would happen. I'm just curious as to how much power they can extract with this technique.

    [​IMG]
     
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  25. GhostRyder

    GhostRyder

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    I was reading up on this and though multiple users have beaten me to the punch in saying it, its a similar system to a Diesel engine. I like the idea, but that high of compression is going to be a bit harder on the engines and require a design that can hold up under pressure otherwise you end up with the Chevy 350 Diesel.
     

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