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Featured Gen 6 Prius engine will be a “game changer,” achieve a 53% thermal efficiency

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by Gokhan, Jun 7, 2024.

  1. Isaac Zachary

    Isaac Zachary Senior Member

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    53% diesel efficiency isn't that impressive (unless, perhaps, it meets stringent emissions levels). The best average fuel mileage I've gotten has not been in either of my Toyota hybrids, but in my 1985 VW diesel. I could get up to 60mpg in that car if I kept the transmission shifted up as much as reasonably possible, and it didn't have any sort of regenerative braking, nor was it near as aerodynamic as any modern car, nor did it have anything close to low rolling resistance tires.

    But >50% efficiency for a gasoline engine is pretty impressive.
     
  2. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Sheetz locally has 87 and 88 octane offered with 88 being cheaper but with 5% more ethanol. Which should I use in a Prius engine from '19?
     
  3. telmo744

    telmo744 HSD fanatic

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    Very big engine, about 1 liter cylinder capacity. My main point is: significant dimension differences.
     
  4. Trollbait

    Trollbait It's a D&D thing

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    What does the manual say? I've used their E15 in the Camry, but Toyota says to stay below E20.

    The components of a car that can use E10 are probably safe with E15. I leave it to the individual decide if they want to take the risk. The extra ethanol in the fuel might cause an engine check light. Nothing was broken, but an operating parameter went outside what the ECU was told was okay.

    Above 50% is impressive for any engine. Toyota's best current diesel is 44%. Your old Rabbit was likely in the 30s. It got great fuel economy because you likely had it running lean all the time. It's a little smog monster then.

    That isn't big. Big is a house sized ship diesel; you can stand in the cylinder. Those are low rpm 2 cycles, and might hit 55%.

    Mass can help thermal efficiency, but the difference between a car and commercial truck engine is tiny. If there is a difference, it may not be measurable.

    Going back to the OT, the new 1.5L NA is more efficient than the old 1.5L. It has one more cylinder though, meaning the individual cylinders are smaller.
     
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  5. Zeromus

    Zeromus Member

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    For me it comes down to use case.

    If transportation can move towards hydrogen, then even if its less efficient than being in a battery, the energy being green to produce hydrogen for use in larger vehicles that travel longer distances with fewer stops which require more power, that's still a net gain.

    For passenger vehicles, honestly, yeah wind/solar onto the grid and into batteries is probably way better assuming it remains much more efficient to do so.

    Imagine if air travel could be done with hydrogen. That would be better than airplane fuel, and its not like you can really use batteries for planes - for example.
    The corn thing is simply because of longstanding farm subsidies, and between tariffs on sugar and the use of ethanol in fuel, they've created a baseline guaranteed market demand for the good setting a defacto market price floor which results in guaranteed income for farmers.
     
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  6. Rmay635703

    Rmay635703 Senior Member

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    Funny thing is that a car could dirive 7-12% more energy from hydrogen if the energy from releasing the compressed gas could be recovered
     
  7. Trollbait

    Trollbait It's a D&D thing

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    Batteries won't work for everywhere. Hydrogen just has issues in transporting and storing it that keep it from widespread use. I can see having a niche use around facilities that make green hydrogen to replace black, or where it is used for energy storage. Like how CNG is used by some truck fleets.

    Transporting it outside those areas can be done, but the costs of building that infrastructure is high. Research is now looking into converting hydrogen into a chemical that is easier and cheaper to transport, or even already has infrastructure, and then separating the hydrogen off at the destination. The carrier compounds, usually ammonia or methanol, can be used directly as fuels themselves. Then for not much more effort, we can convert the hydrogen into an e-fuel replacement for diesel or gasoline. We have plenty of distribution for those, and we can reduce the carbon footprint of existing cars already on the road.

    On vehicles, the hydrogen tanks take up a lot of space. The ones for the pressurized gas are also very heavy. Their lighter for liquid, but you have to except the loss of fuel to venting with them.

    Tiny turbine to help with the 12V load?
     
  8. hill

    hill High Fiber Member

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    It wouldn't be any more difficult than it is in an RV refrigerator. But you're now adding cost for the plumbing to circulate another decompressing gas through your AC lines.
     
  9. Pri3C

    Pri3C Active Member

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    Or bring Gen 2 Prius C that they released in Japan a couple years ago to the US market.

    The fuel economy estimates of the Gen 2 Aqua/Prius C converts to around 85mpg
     
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  10. Trollbait

    Trollbait It's a D&D thing

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    Wouldn't work. Hydrogen is one of the odd gases that heats things up when decompressing. It's why chilling down to -40 degrees is needed for fast filling.
    Japan's estimates are higher than the US and Europe.
     
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  11. Pri3C

    Pri3C Active Member

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    Yes, I remember being told that here when the numbers were released, but I’m pretty sure I also remember seeing test drives on YT where the numbers were around the same.
     
  12. hill

    hill High Fiber Member

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    If you like high efficiency little cars - consider what the head of GM said at the recent shareholders meeting;

    It may not be a Chevy Volt (small car) ,but the tech seems to be getting revived. During the past ½ dozen years our volt (averaging ~90% EV) has averaged ~80mpg equivalent. And that's with a couple cannonball runs halfway across the nation at high speed. But stooping down into a low profile great CD/aero car is getting tougher nearing late 60's age.
    In any event, future GM proclamations are no more or less reliable then Toyota proclamations of future products.
    .
     
    #112 hill, Jun 13, 2024
    Last edited: Jun 13, 2024
  13. Trollbait

    Trollbait It's a D&D thing

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    Sure it's possible. Some did so with the gen1 Aqua. Getting the gen5 Prius over 90mpg is also possible. Even for a cross country trip. Doesn't mean it's a number comparable to the EPA rating of another model.
     
  14. Zeromus

    Zeromus Member

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    I think more PHEVs are probably going to be coming as a response to tooling of factories, costs and limitations with Battery production, etc. Likely coming to a similar conclusion as Toyota - seeing how well hybrids in general sell for them and extrapolating to PHEVs given regulations about future zero emissions sales requirements in the 2030s.

    For every BEV, they can make multiple PHEVs, and they don't need to retool as many factories, meaning lower investments required in the short term when economy looks to be entering a downturn part of the economic cycle, and likely driving appetite for smaller more affordable cars with high levels of energy efficiency. Easier to make an existing model/design a hybrid or PHEV, than new platforms for EVs in the small car segment. Especially since GM's BEV segment seems to be focused on SUVs like the Equinox, Blazer, Bolt EUV, etc.
     
  15. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    This is an honest question: why would I care what the head of GM thinks? They've already announced the discontinuation of the last few cars I actually liked from their stable.

    I recognize them for having their finger on the pulse of what their dealers want, but there's no overlap to what I want.

    Detroit's big three are dead to my dollars.
     
  16. PiPLosAngeles

    PiPLosAngeles Senior Member

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    Driving any gas car that gets better than 30 mpg is cheaper than driving a BEV if you're having to pay afternoon rates to PG&E or Edison. Driving the Prime without charging costs half what it would cost to drive on an afternoon charge.
     
  17. hill

    hill High Fiber Member

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    That's why I went PV solar in 2009. Dropped our So Cal Edison bill that represented charging 2 car costs (as of 2011/12) & running the house electricity to $0.00
    That's better than 10¢ gas.
    We sold that house a couple years ago but the solar paid for itself in the 1st 6½ years.
    ;)
    .
     
    #117 hill, Jun 13, 2024
    Last edited: Jun 13, 2024
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  18. Gokhan

    Gokhan Senior Member

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    But those engines couldn't even pass the California emissions tests of the 1980s, let alone the modern emissions tests.

    The whole point of the Toyota paper is to achieve super lean burn without the high NOₓ emissions.
     
  19. austingreen

    austingreen Senior Member

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    Toyota has had a turbulent jet ignition (tji) engine in a super gt lexus since 2018. TJI works on an old idea from the cvcc using a pre combustion chamber and was first introduced by mercedes in an f1 car in 2014.

    Turbulent Jet Ignition: The next stage in GT500 engine development – Super GT World

    This is one way that toyota has been working on for years and it allows a more efficient cooler lean burn which should lower NOx. That old Honda didn't have a cat, I'm sure the new engines will.
     
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  20. Gokhan

    Gokhan Senior Member

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    Of course the 1980s cars had catalytic converters. Lean burn still increases the NOₓ a lot. I don't know how lean is that Lexus. There is lean burn, and there is super lean burn. Technically, most engines since the 1980s employed some degree of lean burn. My 1985 Corolla engine was 4A-LC, L standing for lean burn and C for emissions controls, even though I don't think there was any combustion tricks. It was mainly the carburetor and emissions controls that were adjusted for a slightly leaner combustion. Just like in the Volkswagen diesel standard, emissions and fuel efficiency/horsepower conflict with each other. I could set the ignition timing further advanced in my old Corolla to obtain more power, but it increased the emissions.

    New Honda engine a no-go in state: Technology: The ‘lean-burn,’ fuel-efficient model emits too much nitrogen oxide to comply with California pollution regulations.—Los Angeles Times
     
    #120 Gokhan, Jun 14, 2024
    Last edited: Jun 14, 2024