40%-Efficient Engine, Really?

Discussion in 'Prime Technical Discussion' started by mr88cet, Apr 24, 2017.

  1. GT4Prius

    GT4Prius Active Member

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    Combined Heat and Power where much of the heat is recovered rather than wasted to atmosphere is a widely used and established technology. Can also be used on smaller scales for a smallish group of domestic properties, large hotels, for industrial purposes and for things like Public swimming pools.

    There has been plenty of debate about this as a way of improving electricity generation efficiency nationally, but most countries are too invested in terms of infrastructure and politics to large scale generation and national distribution grids which then make CHP impractical to fit that model and predisposition.

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  2. Dale Leonard

    Dale Leonard Member

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    An atomic power plant is 1% efficient.
    Talk about wasted heat.
     
  3. fuzzy1

    fuzzy1 Senior Member

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    By what measure?

    Certainly not by the usual definition of thermal efficiency, the conversion of thermal power to electrical power, where nukes are typically around 30% efficient.
     
  4. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    I would also like to be able to change engines twice per season :)

    I'm very amused someone with the username Ferrarilover liked your post.
     
  5. AJDL

    AJDL New Member

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    How do you calculate the gasoline mileage? I am not able to find any option on the car to see, how much it is consuming or MPG. It shows MPG but that includes the EV.
     
  6. Lee Jay

    Lee Jay Senior Member

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    So what? When you are in Hv, especially if you are in Hv for a long duration or when you start and end with the same remaining Ev range, all the energy is coming from the gas engine, regardless of the Ev percentage.
     
  7. Trollbait

    Trollbait It's a D&D thing

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    I think he means the MPG figure includes energy from the grid, which would make it inaccurate.
     
  8. Lee Jay

    Lee Jay Senior Member

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    But it doesn't.
     
  9. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    @Tideland Prius and all, that intake manifold cross section through the EGR looks to illustrate that the passage goes from one, to two, to four, somewhat akin to a family tree. I can see the advantage there: more even distribution. Third gen has a single long passage, with a side branch at each cylinder port.

    OTOH, it looks to be near impossible to completely clean mechanically, to run pipe cleaners through. You could still do spraying, anyway. I believe the 4th gen EGR intake is moved further downstream, beyond the catalytic converter, reducing the need for intake manifold cleaning. Hopefully.

    upload_2017-9-18_10-49-20.png
     
  10. Tideland Prius

    Tideland Prius Moderator of the North
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    Would a cleaner burning engine result in less potential soot in the exhaust gas that is recirculated?
     
  11. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Maybe. But I've got an undeducated hunch a lot of that soot is due to the PCV dumping oil from the crankcase. I found my intake manifold to be an oily mess, the MAP sensor more-or-less drowned in oil.
     
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  12. bhtooefr

    bhtooefr Senior Member

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    At least based on the TDI world's experience with this, it's not the PCV, it's the EGR. (Granted, TDIs have a turbocharger that seeps a bit of oil into the intake, so removing the PCV doesn't remove all of the oil, but still, it removes a lot of it.)

    Reducing particulate matter in the exhaust pre-EGR - whether that's through more complete combustion, or through removing the PM from the exhaust pre-EGR, will help.
     
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  13. bwilson4web

    bwilson4web i3 and Prime

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    Same fuel, I suspect no. Change the fuel to higher hydrogen to carbon ratio, methane, methanol, or hydrogen, and soot can all but disappear. Although not designed as particle filters, their heat, 600C, and alternating reduction cycles should reduce soot too.

    The catalytic converters have been and remain a game changer.

    Bob Wilson
     
  14. Tideland Prius

    Tideland Prius Moderator of the North
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    Question about Shell's "Nitrogen-enriched" fuel. Would that not result in more NOx emissions? Or do the benefits that it supposedly brings, offset that?
     
  15. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    My bet: "Nitrogen enriched" is marketing, not chemistry.
     
  16. bhtooefr

    bhtooefr Senior Member

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    Adding more nitrogen in the fuel won't have an effect on NOx emissions, I suspect - there's already an excess of nitrogen in the intake air, and the high temperature reaction between that nitrogen and any excess oxygen in the cylinder is what forms NOx.

    That's why gasoline engines tend to have better NOx emissions performance - the throttle plate means that excess air isn't entering the cylinder in the first place, whereas diesels run wide open. And, that's why lean burn gasoline engines aren't common - lean burn means NOx.
     
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  17. Lee Jay

    Lee Jay Senior Member

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    Gasoline engines have lower NOx because of less compression leading to lower peak combustion temperatures than diesels.
     
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  18. Tideland Prius

    Tideland Prius Moderator of the North
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    Would be curious to see how Mazda tackles the HCCI engine they have coming down the line.
     
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  19. RonMc5

    RonMc5 Member

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    Like the 400 HP of the 60s was brake HP on a bench dyno. Now called (I think) SAE gross HP, newer is SAE Net HP, with like pumping it's own coolant and other accessories attached and in street trim. DIN HP was always like SAE net, and a more realistic figure. :)
     
  20. mr88cet

    mr88cet Senior Member

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    I think I recall that they compress almost to the compression-ignition point, and then ignite “normally” an extremely tiny amount of gas whose sole purpose is to tip the pressure over the threshold.

    Ah:
     
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