Fuel efficiency

Discussion in 'Australia' started by GodSilla, Jun 6, 2018.

  1. GodSilla

    GodSilla I did that.

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    This came up in another thread, but I think it deserves it's own thread.

    Eggzackerlee. This is a subject that was once fairly prominent, but (just like 'planned obsolesence') it has been deliberately and quietly dropped from social discourse.

    Despite 50 years of "progress", more than half the fuel still comes out the exhaust port unburnt. Dumb dumb dumb dumb dumb.:jump

    FWIW, as I understand it, Ralph Sarich was disturbed at the fuel consumption of his radical Orbital engine (an insoluble problem sadly). He experimented, then fitted his own design injection to a Suzuki 3-cylinder 800cc (?) motor fitted to a 2-litre Holden Camira, then drove it from Perth to Adelaide (from memory) at normal speeds and performance levels and got in excess of 90 MPG. His fuel injection design managed to burn over 90% of the fuel, which is where he got the power and economy from, instead of just blowing most of it out the tailpipe unburned.

    That technology was bought and buried. Personally I find that criminal.
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  2. wairau

    wairau get in behind!

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    er :scratch

    you sure?
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  3. GodSilla

    GodSilla I did that.

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    Yup.
    Putting an extra spark in when the exhaust is being voided is a workaround to burn some more off in the exhaust to reduce emissions, almost universal these days, but that's post-combustion.
    The issue is with the atomisation of the fuel in a traditional carby or injector. While an injector theoretically gives you more control over the fuel delivery it doesn't actually do that much better a job at atomisation. There is a large variability in the size of the fuel droplets in the combustion chamber, and the problem is they burn at vastly different rates, comparitively speaking. This is the problem that Ralph Sarich largely solved.
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  4. wairau

    wairau get in behind!

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    why do they put all that fuel in there when half it doesnt get burnt?
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  5. GodSilla

    GodSilla I did that.

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    'Cos that's how it worked in the early days when there was lots of cheap oil for fuel making.

    If you check current fuel efficiency figures they haven't really moved much in 40-odd years. Cars are newer, more advanced, supposedly better, but they still spew more than half the fuel out the exhaust valve unburnt.

    Keep in mind that there area whole industries built around the existing investment in internal combustion engines, from manufacture to purchase to maintenance to wrecking, squillions of people depend on it for income. The inertia is huge. Industry is conservative as well, generally speaking.

    Sarich got bought out by Ford eventually (again, from memory) and they quickly buried his injection system, but aspects of it have cropped up on some of their brands' marine outboards as I understand it. Mercury is one.

    The car makers care about selling you a car. The fuel producers care about selling you fuel. Both take great effort to do the minimum required to achieve that. If the buying public doesn't complain loudly about fuel efficiency, they don't care to address it either.

    Just as an aside, if the Sarich injection was mandated on passenger vehicles and commercials, fuel consumption would drop to near 1/3 of current usage. This scares the crap out of the oil producers. If they had any brains though they'd see that charging 3 times as much would restore their profits, the motorist pays the same per km but has a cleaner conscience to match the cleaner burning, and the resource lasts 3 times as long (with 3 times the profits....).

    Everyone wins really. It's a no-brainer to an outsider.:dunno
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  6. bigborett

    bigborett Hipster

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    [​IMG]
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  7. Blakduk

    Blakduk Just trying to get by.

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    I call bullshit on you @Godzilla . If a car manufacturer in Korea or in Japan could give me 90 mpg out of the little engine with the same power (which I think is what you are alluding to), then they would. People would buy them by the millions. Or China would do it. So I think there is no conspiracy.

    As for saying fuel efficiency hasn't moved in 40 years. That is so obviously bullshit I'm surprised you have the balls to say it.
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  8. DRjoe

    DRjoe Long timer

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    codswallop
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  9. Wodger63

    Wodger63 Long timer

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    :lurk
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  10. wairau

    wairau get in behind!

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    you mean to say that, you put in the exact amount of fuel that uses up all the oxygen in the combustion chamber and it makes some power. then you put in a whole bunch more, just to spew it out the exhaust without burning it like 'silla says and it makes more power?

    this is all very confusing.
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  11. Big Willy

    Big Willy Gen. Italia

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    It's a tricky one and there is a limit. I know because if I leave my choke on, the motor runs like shit.

    Then again there may be something to do with the cooling effect of fuel enabling more compression...don't know, just putting it out there.

    @KASUYAHO may be able to tell us from his dragracing days
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  12. Mouse

    Mouse I'm only smelly

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    Sarich technology = optimax outboards. Works very well, bit mechanically complex perhaps but real good thing imo.

    I could be easily wrong but I don't think any of the car makers wanted his tech, mercury ran with it to keep their 2smokes compliant in california...
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  13. DRjoe

    DRjoe Long timer

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    And tohatsu, bombardier and i think aprilia used it as well.
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  14. Cruz

    Cruz Lost but laughing.

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    Ha, anyone would think you might know something about outboard motors. ;)
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  15. Mouse

    Mouse I'm only smelly

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    Bombardier? Same clan as evinrude and their etech? I don't know much bout the etech but don't think it's an iteration of sarich tech.
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  16. DeLewis

    DeLewis Been here awhile

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    No knowledge of the Sarich tech BUT Godsilla’s post touches on something that has always baffled me and for which I cannot find an answer: why are motorbikes so hugely inefficient compared to cars (or just about any larger vehicles)??

    My 701 consumes roughly 4.3lt per 100km (commuting). It weighs 145kg + rider with gear 85kg. Total weight ~ 230kg. My wife’s car - Honda CRV (current model) weighs 1500kg + driver 75kg (me not her) - total weight ~ 1575kg. It consumes about 9.6lt per 100km. Bit over double and yet it weighs almost SEVEN times more than the fully laden bike. What’s going on?! Yeah bikes accelerate harder but that cannot explain more than a small margin.

    Are there economies of scale that apply? ie. a lot of the fuel is consumed just through mechanical loss within the engine so that the extra work to move a larger mass is a smaller component of the consumption? And WTF does this have to do with a KTM on the drawing board:-)
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  17. Cruz

    Cruz Lost but laughing.

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    Look at the Honda NC750X with a motor much like a cars and look at the mileage it gets. Easily around high 60's and into the 70's, take it easy and some owners report into low 90's. The bike isn't a light weight racer either, around 225 kg fuelled up.
    That may give some pointer.
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  18. ToriMish

    ToriMish Long timer

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    I looked into the Orbital Engine after the post - interesting and I didn't know about it at all. However, I am unsure about the conspiracy - some of the articles I were reading indicated the engine was quite impractical and prone to overheating - leaving the engine as overly impractical.
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  19. flinders_72

    flinders_72 Long timer

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    kW/tonne, mainly.
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  20. DRjoe

    DRjoe Long timer

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    They used the tldi system before they went to the shit box hunk of crap that is etec
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