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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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    Or a Corolla sedan pretty please with sugar on top!

    Too bad there's zero way this is going to be a fun drive train to drive, at least for my weird tastes. But then again at least it's practical and there just aren't any fun cars anymore anyway.
     
  2. Trollbait

    Trollbait It's a D&D thing

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    Because Toyota also talked about these engines using carbon neutral fuels and expanding the fuels adoption, including hydrogen.

    This is not a gen6. It is a gen5 with a new engine swapped. A gen6 would take advantage of the smaller engine to have an even lower profile.

    That engine could be connected to the the gen5 transaxle, or the one from the Aqua. The intake manifold is much different than the display engine. It could be the turbo version. All the photos are from one side, making it possible the turbo is out of sight behind the engine. You have to be right on top of the Sonic engine bay to see the turbo and compressor.

    This car may not even run.
     
  3. Gokhan

    Gokhan Senior Member

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    Sure, they could have a hydrogen version, but it would be a separate engine and not a mainstream one. They only used hydrogen injection in the paper because otherwise, they wouldn't be able to achieve combustion in the existing engines they studied with the very large super-lean-burn stoichiometric ratio λ they experimented with. The all-new engine uses a stratified mixture (richer mixture at the spark plug) as opposed to a homogeneous mixture to achieve combustion among other things and does not require hydrogen.

    Yes, it is a Gen 5 with a pseudo Gen 6 engine. The car will hopefully run one day, but yes, everything is a test at the moment. :)
     
  4. hill

    hill High Fiber Member

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    Looks like China is beating the tar out of Toyota & most other manufacturers when it comes to high efficiency engines. Theirs are not still on the drawing board, either. Consider Chinese manufacturer Weichai;

    Weichai Power breakthrough: Diesel engine efficiency at 54,16%.

    Their diesel efficiencies are pretty dang efficient too. Shouldn't we rather be impressed by stuff in existence - rather than what might come to be?

    .
     
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  5. telmo744

    telmo744 HSD fanatic

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    Not comparable.
    Truck diesel engine vs passenger car gasoline engine
    (different cycles and very different cylinder capacity/dimensions)
     
  6. austingreen

    austingreen Senior Member

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    Totally agree, with so little hydrogen infrastructure, toyota is talking about to work in the distant future. in a phey with an ice hydrogen makes more sense than fuel cell as costs will be lower and efficiency not much different.

    What they said was there work with hydrogen, which makes me think of more cooling with the fuel. We have a lot of examples of water injection - water mixed with a little alcohol (usually methanol), injected to cool the air fuel mixture, as well as reduce pollution in a lean burn and allow for higher compression without detonation. IDK, we will find out when they they release the engines. You can use it without alcohol, but the alcohol allows better combustion as it raises the octane.

    I think as with the current prius the engines will use a port plus direct injection. That direct injection is where I would expect the water to work best, and they may have more than one direct injector. Most after market water injection kits work on the port injection and are used to mainly allow higher compression for more power, but it also makes them more efficient.
     
    #86 austingreen, Jun 12, 2024
    Last edited: Jun 12, 2024
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  7. Zeromus

    Zeromus Member

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    The idea that they'd make a car with an even lower profile is wild to me. It's already pretty small, at some point the overall profile of the car can't get much lower and still be practical.

    Though, maybe it opens up options for them to have fun GR models, or to put an engine like this into a TRD car like the Yaris for the engineering challenges that they push through that program.

    What a smaller engine does do is allow for something like a Yaris with this engine to get obscene levels of fuel efficiency. Just because it's smaller doesn't mean the *roofline* of a car and profile needs to be smaller. It can also mean the engine bay can be tinier. But that also has limits, since there are safety requirements, crumple zones, that kind of thing that a smaller engine doesn't change. Part of the reason some of the chinese EVs have bigger length models globally is related to this issue. At some point, there's a size of car where safety related engineering puts a limit on what you can do.
     
  8. Trollbait

    Trollbait It's a D&D thing

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    2035. New cars for Europe will have to be zero carbon. There is lobbying for other carbon neutral fuels, but right now that means EV or hydrogen. Toyota is going to be developing these engines for hydrogen along side gasoline. They could introduce hydrogen injection to help spur hydrogen growth, and to meet emissions.

    Honda did stratified charged engines in 1980s. This isn't part of the 'next great thing'.
    True, but Toyota's diesel isn't much more efficient than their current hybrid engines; 44% thermal efficiency. Maybe they're planning something. It's been almost a decade since that engine came out.
    Toyota's Revamped Turbo Diesel Engines Offer
    More Torque, Greater Efficiency and Lower Emissions | Toyota Motor Corporation Official Global Website


    Diesel has drawbacks, but they do work well for commercial uses. Even better efficiency will allow the stretching of carbon neutral fuel supplies.

    In the posted paper, Toyota used ethanol addition in the turbo lean burn engine to reach higher efficiencies. It didn't discuss it, but a couple of figures included a hydrogen injected engine. Those were about NOx emissions, and the hydrogen injection was the only way to reach the low target amount. Other work with hydrogen injection for cleaning emissions has been done.

    A goal of Euro 7 is to lower NOx by 35% compared to Euro 6. The lean burning OG Insight needed a NOx trap back in 2000. The impetus for developing these engines was that the current engines would need more exhaust treatment and depowering to meet those new limits. For the naturally aspirated new engine to reach high efficiency, that will likely mean very lean burn. Toyota could be planning/hoping to use hydrogen to not require a full suite of diesel engine emission controls.

    The test engine did have two injectors; one to fill the cylinder with lean mix, and a second to 'prime' the spark plug with fuel for ignition.

    Particle emissions was one of the main drives for using port with direct injection. Without it, a DI engine needs an exhaust filter under Euro 6. Euro 7 will lower those limits by 13%. In addition, the measured particle size is moving from 23nm down to 10nm. The port and direct injection may require an exhaust filter under Euro 7. In which case, why continue with the cost and space of having port injection?

    Euro 7 is also requiring longer lifespans to emission controls. Plus, will cover EV battery life.
    https://ec.europa.eu/commission/presscorner/api/files/document/print/en/ip_22_6495/IP_22_6495_EN.pdf
    Euro 7: Deal on new EU rules to reduce road transport emissions | News | European Parliament
    https://theicct.org/wp-content/uploads/2024/03/ID-116-%E2%80%93-Euro-7-standard_final.pdf
     
  9. Trollbait

    Trollbait It's a D&D thing

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    These engines aren't intended to be used with an electric motor. The 1.5L NA may even be intended for PHEVs only when talking models larger than an Aqua. So smaller over all sized engines mean more space for the electrical side. Toyota does make a point about how the shrinkage allows the dropping of the hood line and how the aero change can improve efficiency. There was one diagram also showing the roof line drop, but that could have been using a typical sedan as the start point.
     
  10. Zeromus

    Zeromus Member

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    Oh yeah, good point about the typical sedan thing. I just made the obvious assumption because, well, they literally put the picture next to an example of the engine size inside of a gen 5 prius.

    On the stratified hydrogen engine side, I just still don't see a world where hydrogen FCV overtakes BEV. The infrastructure just doesn't seem to be something anyone is interested in developing or expanding. I think it would take a single minded, and very intentional push to implement something like Tesla's charger/supercharger network. I think the biggest thing Tesla has done for BEVs may not even be the cars themselves, but the fact that they put in so much infrastructure to make BEVs palatable and possible for a significant number of drivers.

    If hydrogen is going to be a real, viable, option - which on paper solves a lot of BEV issues, it will definitely need a very concerted effort to make the fuel available. I just don't know that any manufacturer is willing to take the risk of co-launching FCV based cars, at scale, alongside even an existing large scale gas company, to offer hydrogen at a lockstep scale.

    At the very least, BEVs had the added side benefit of being able to charge almost anywhere - even if slowly - to avoid there being a literal maximum range they could *ever* go. You run out of the hydrogen fuel and aren't anywhere near an appropriate fuel station you're stranded. You run low on charge, you can plug in to any outlet and *eventually* get enough energy to move on.

    The range anxiety hurdle BEVs faced early on, at least had what could be considered a pressure release valve available to them. Hyrdogen cars do not.

    BUT if a major company like, BP or Shell for example could add hydrogen to X% of stations all over the world... things would change on that front quickly. But, given the growing ubiquity of the BEV platform, I just don't know that this is going to, really, be a viable alternative.
     
  11. hill

    hill High Fiber Member

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    Don't miss the forest for the trees. Mentioning the efficiency of the Weichai diesel improvements is only a side note. The main point is that Weichai's natural gas ICE efficiency is already at 54%.
    NOx reduction in gasoline exhaust is similarly an issue with diesel - so you can't just sweep the issues under the rug as totally unrelated. Diesel NOX is mitigated by injecting urea into the exhaust. That cleans exhaust to the point that tailpipe emissions become nitrogen/ ammonia., CO2 & water.
    The notion of injecting gasoline ICE with hydrogen begs the question "where does the hydrogen come from". The least "outrageously expensive" hydrogen currently is reformation via fossil fuels. Wind or PV solar hydrogen distillation is green, but it begs the question why use that power for hydrogen distillation when it's more than a 3-fold better efficiency use putting the electricity into a battery.
    Choosing a plan of action, do the one that's the least dumb.
    .
     
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  12. austingreen

    austingreen Senior Member

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    Where does the hydrogen come from if not from a hydrogen station? Well we have had kits for 30 years, that can use electricity to create it. They claim to increase efficiency but if they really did big auto would be doing by now. What it has been shown to do is reduce emissions in diesels.

    Hydrogen injection device saves fuel and cuts emissions on big diesels

    The conservation of energy just doesn't work for making engines more efficient though, that is no one has shown that to work despite the claims. Maybe toyota will use a fuel cell instead of electrolysis since that is more efficient, and maybe they will charge the battery in a phev with renewable energy and not count that as an energy input. I doubt either of these things are going to happen. Water injection has been proven to reduce pollution and increase efficiency and requires a lot less hardware. Still maybe they are planning on renewable hydrogen tanks sitting in the trunk what you can buy from the toyota dealer ;-)

    Lets wait for a real engine and benchmarks before even thinking of the hydrogen hype.
     
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  13. ColoradoBoo

    ColoradoBoo Senior Member

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    Always interested in Toyota's R&D projects. I have to admit, I'm not completely sold on Turbo, even from Toyota, which is why I don't have one. If I do ever get one, that engine oil is getting changed every 3,000 miles.

    For the 1.5L, I'm wondering if it'll be using 0W-08 motor oil? I wouldn't run out and buy one right away, better to wait 6-9 months after they start selling to see if any real-world issues come up....last few Toyota new Gens have all had initial issues, some major! (Not fun)
     
  14. Trollbait

    Trollbait It's a D&D thing

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    That was my criticism of Toyota and others pushing hydrogen cars; they weren't investing in the infrastructure to support them. It highlighted a lack of seriousness they had in the fuel. Fuel cells could have become competitive in price, if more were made, but infrastructure needs to be in place to support the cars before people buy, but there wasn't any, so FCEV prices stayed high, and no one bought them.

    The endeavor was going to take a major capital investment to start, and the car companies hoping to make money of it wanted the public to make that payment.

    Toyota is experimenting with hydrogen engines. The cars would be cheaper, so they can support the hydrogen network until the FCEV prices drop. California's ZEV program once would have supported them. Would have made sense to try selling them back then, along side a FCEV model, but they didn't. In fairness, I suspect the NOx emissions might have been the issue.

    Hydrogen injection of diesel and gasoline engines has been shown to reduce emissions. Perhaps using it for that purpose could wean people onto using it as a fuel.:unsure:

    Honda's upcoming FCEV CR-V will have a plug. I just think the space needed for hydrogen tanks will compromise most PHEV designs.

    Three way catalytic converters do a pretty good job of cleaning up CO, HC, and NOx in engine exhaust when the engine is running stoichiometric fuel ratios. The cat needs to right mix pollutants to clean them all up, as it getting them to react with each other. Change the fuel ratio, and too much of something is made for the cat to clean up. That something is NOx when the engine is running lean.

    So other means of getting rid of the NOx are needed. Right now, the main methods are a trap and SCR. A trap catches NOx when the amount produced spikes up, and then releases it at a slower rate that allows the three way cat handle it. SCR is more effective; it uses a second catalyst that reacts the NOx with urea or ammonia, so it adds more equipment and maintenance to the vehicle. The two can be used together.

    Those systems have added to the costs of diesels, and reduced performance in some cases. Lean burning gasoline engines may need them. Hydrogen injection has been shown to reduce emissions, and adding it will likely be cheaper than the exhaust after treatments.
     
  15. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    People keep bringing this up. But the fact is that green (or even greenish) hydrogen is much more expensive than electricity.
    So it is NEVER (IMO) going to be a viable alternative for mass market cars. So no company is going to make a big push for it by installing lots of hydrogen refueling stations like Tesla has done with Superchargers.

    Mike
     
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  16. Trollbait

    Trollbait It's a D&D thing

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    Which is why many car companies switched to commercial trucks only for their hydrogen development. Such might be a better solution for some roles than BEV. Then we will need green hydrogen for other purposes. Production regions could support local truck fleets.
     
  17. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    By commercial trucks, do you mean semi trucks hauling products around? Or things like tractors on farms and dump trucks? Or local delivery, like from Amazon?
    I doubt that the extra expense will work for bringing products to people or stores. Why pay extra for this when most of that can be served from a Tesla semi or one of the many others like this?

    Mike
     
  18. Trollbait

    Trollbait It's a D&D thing

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    The ones being developed are box trucks that can be adapted to multiple roles to semis. Things that need a CDL.

    We make a lot of hydrogen from fossil fuels. Going to have to make a lot of green hydrogen to replace it. Hydrogen could also be used for grid storage in regions where batteries won't work. Why pay to install the high power chargers and grid support that a BEV truck fleet would need when the hydrogen is available?

    There are also other roles to consider that could be a better fit with available hydrogen than batteries. Such as trains.

    Making green hydrogen for cars and trucks is silly, but when the production scale is large enough to meet our current needs, say ammonia for growing food, then some excess going to transportation might be better than BEVs for some location and roles.
     
  19. ColoradoBoo

    ColoradoBoo Senior Member

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    That's true and the Flex Fuel push was proof that letting the gubmint tell the private sector what we can and can't do should be VERY limited.

    How much money did Toyota and other auto makers spend developing engines that can run on it? Who decided that taking food (corn) and turning it into fuel was a good idea? It's bad for the engines, costs a LOT more, and you get much lower MPGs....three strikes and you're out! (My Tundra has a flex fuel engine but will never be used for it.)

    Sorry gubmint, stick to keeping our water clean and leave our cars alone!

    • "Government's first duty is to protect the people, not run their lives." --Ronald Reagan
    • "Government does not solve problems; it subsidizes them."--Ronald Reagan
     
  20. Trollbait

    Trollbait It's a D&D thing

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    That was more the corn and ethanol lobbies getting government to force something on the public. Earlier test programs was allowing other alcohols and fuels as part of the mix.

    Much of the R&D for ethanol was already done. Ford was pushing ethanol as an octane booster before Dupont got their way with lead. Flex fuel engines just needed a fuel sensor, higher flowing injectors, and fuel system components hardened against the alcohol. Was less than $100 for the manufacturers. Would have been better if they used a high compression engine for conversion. Then the high octane of ethanol could be used to offset some of the mpg loss, but the car companies just wanted to sell as many as they could.

    That's where the government messed up. The CAFE incentives for flex fuel cars got manufacturers to put the engines in nearly every model, but there was no substantial support to get stations to sell E85.

    Now without the adoption of E85 happening, the ethanol lobby wants E15 mandated as the minimum alcohol level.