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Diesel Prius

Discussion in 'Diesels' started by cmth, Sep 13, 2013.

  1. cmth

    cmth Active Member

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    Thanks to all those who contributed to this thread.

    I started off with a simple question - why not a diesel prius ? The technical challenges, it is safe to say, can be overcome but there seem to be so many other factors that matter - this is what I learnt. I am sure the feedback would have been very different had I asked this question in a clean diesel forum - perhaps a bit more positive I would guess.

    At the end of the day, I still think Toyota has overlooked a great opportunity here. Toyota could have done a great diesel hybrid. Knowing Toyota it could have been priced just right so most consumers could afford it, it would be reliable and cheap to run/maintain. In other words, the balance of traits would have been just right for the ordinary consumer. Alas that wasn't to be!

    Anyway, as I look forward to Prius Gen 4, I really really hope this will be a game changer - never again do I want to hear of another car that is significantly cheaper yet close to or better than the Prius where it matters*.
     
  2. GasperG

    GasperG Senior Member

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    A Prius engine has a torque, power and complexity similar to 1.33 VVT-i engine, the HSD works like an ideal transmission, every speed you chose you can have almost any rpm you need, the only problem is the noise of the engine. A diesel engine (or Turbo petrol) is designed to work very good and efficient with a stupid gearbox, Prius gearbox (HSD) is designed to work with low torque stupid engine.

    Let's look at the Auris example, a normal 1.33 Auris is getting around 7 l/100 km, Auris hybrid is getting 5 l/100 km or 28% improvement in consumption and 36% improvement in performance and 5,400 € price premium.

    Let's look at the Peugeot Hybrid4 (diesel). There is very little data on spritmonitor but nevertheless I think we can draw a conclusion:
    Peugeot 3008 Hybrid4: 6 l/100 km data1 data2
    Peugeot 3008 Diesel: 6.5 l/100 km data1
    Peugeot 508 Hybrid4: 5.3 l/100 km data
    Peugeot 508 Diesel: 6 l/100 km data

    I see only around 10% improvement in consumption, but higher performance (33-44%), 4 wheel drive system and 6.700 € price premium.

    My point is If you combine a complicated expensive smart engine (diesel) with expensive smart drive train (HSD) you are way out of "comfortable" hybrid price premium and you are getting only 10% in fuel economy improvement. The only way to offer that kind of car on the market is to offer something more (200HP, 4WD). I think the Toyota engineers are really working hard to keep this simple engine approach in next gen Prius, there will be no turbo, maybe even no DI, some other simple tricks will have to boost efficiency of next Prius.
     
  3. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Why not have Rosanne Bar compete on Dancing With The Stars?
    I mean....yeah....it's possible....she could do it..... but....why? :eek:

    Same thing.
    Oil burners have their place on the roads, as do EVs.
    I see absolutely no benefit in replacing an ICE Prius with a Prius Diesel.

    IMNTBHO, It's a solution searching for a problem.
     
  4. Braddles.au

    Braddles.au DEFAnitely using an EBH

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    The Volvo PHEV Diesel is solving a very different problem, that being that old chestnut of needing a large station wagon with occasional AWD and 1800kg towing capacity that can become zero-emission on demand.
    So a diesel Prius in a medium-sized hatchback form factor doesn't make sense. Diesel is better when the vehicle will carry heavy loads, because the weight penalty is nowhere near as great on fuel economy.
     
  5. engerysaver

    engerysaver Real Senior Member

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    Any idea's on using LPG ??
     
  6. GrumpyCabbie

    GrumpyCabbie Senior Member

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    Some have done the conversion but whether spending £1,500 ($2,500) on the conversion is worthwhile is debatable. You lose about 25% power and economy with lpg but it is half the price of petrol - about the same as what you pay for petrol really.
     
  7. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    If I were going to limit my range and tie myself to a dodgy infrastructure, then I'd just go EV...or PHEV and keep the ability to go outside the city limit.

    However (comma!!!) LPG would probably work better for your tow-beast, especially since it's already huffing alky/water vapor. :)
     
  8. Quentin

    Quentin Member

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    Diminishing returns. One could argue that the Prius is already pushing into diminishing returns at these lowish gas prices. A diesel would just make it more expensive, less reliable, and marginally more efficient.
     
  9. GrumpyCabbie

    GrumpyCabbie Senior Member

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  10. wxman

    wxman Active Member

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    Then the EU needs to start focusing on particle emissions from direct-injection GASOLINE (GDI) engines...

    "…Compared to diesels, a bigger contribution to airborne nano-particle emissions made by gasoline engines especially DISI (Direct Injection Spark Ignition) engines has been recognised….

    …A number of researchers have shown that gasoline engines produce much smaller particles (nanoparticles) than diesel engines…."

    Source: Chen, “Measurement of Particulate Emissions from Gasoline Direct Injection Engines.”, August 2008, Measurement of Particulate Emissions from Gasoline Direct Injection Engines | Longfei Chen - Academia.edu


    "…New DI Gasoline Engines Said to Emit 1,000 Times More Harmful Particles than Older Ones…"

    Source: New gasoline engines emit 1,000 times more particles than predecessors, study says
     
  11. GrumpyCabbie

    GrumpyCabbie Senior Member

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    A start would be the diesel engines.

    Easy to work out that they're the problem.

    Europe has horrific air quality in cities and large numbers of diesel vehicles.

    The US has issues with smog, but compared to Europe it's clean. The US doesn't have as many diesels.

    I wonder what the air quality of the US would be if they had the fuel economy standards of Europe but with the existing US emission controls.
     
  12. wxman

    wxman Active Member

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    Even if that is true (and I'd like to see actual monitoring data to be convinced diesel is the problem), it's because of legacy diesels. As I'm sure you're aware, Euro 5b has a particle number emission limit for diesel vehicles (6X10^11 particles/km) which is a very strict emission standard and went into effect in 2011. It is currently being proposed that GDI be given an order of magnitude leeway in PN emissions under Euro 6 (6X10^12 particles/km - Emission Standards: Europe: Cars and Light Trucks - footnote (g) in Table 1).

    According to a recent report by the European Commission (Institute for Energy and Transport), GDI vehicles currently exceed that diesel limit by one and a half orders of magnitude.
     
  13. GrumpyCabbie

    GrumpyCabbie Senior Member

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    You sound like an engineer. There's a big difference between sticking a car on a rolling road and the real world. I have to live in cities that stink of diesel - literally. And before you say it's a legacy issue, London has banned vehicles that don't comply with minimal standards, yet it still stinks. Why? because diesel emissions in real life don't work like they should.

    Have a read of those. I have to live in the diesel stink.

    Diesel dominance threatened by EU emissions rules | Autocar

    Vehicle Emissions | Air Pollution | City Diesel | LPG | CNG

    About the LEZ | Low Emission Zone | Transport for London

    Diesel engine exhaust fumes are 'major cancer risk' | Mail Online
     
  14. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Right, the pollution is only because of every diesel ever actually made, not these fantasy diesels we would like to convince you work.

    Every diesel site I have visited has lively threads on how to remove the emissions controls, as did gas engine hot rodders in the 70s. Once gas engines with proper emissions controls could produce the same power and MPG as pre-emissions engines, that dried up. Let me know when diesels that meet your brand new standards are as cheap to operate and as durable and powerful as the pre-emissions diesels were.
     
  15. hlunde

    hlunde Member

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    All diesels are direct injection and start faster (when warm) than port injection, e.g., Prius. Port injection requires air flow from the manifold to draw the charge into the cylinder. A diesel cylinder full of air will fire on first compression when injection occurs.
     
  16. wxman

    wxman Active Member

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    Actually, I'm not an engineer. I served as an air quality forecaster in the U.S. NOAA from 2004-2012 (Retired in 2012). I have been involved in various aspects of air quality/pollution in some capacity since 1985. I have more than a cursory knowledge of the topic.

    You mean like GDI?...

    "…Direct injection gasoline engines are more dangerous than previously known to man and the environment. This is the result, a new test that the German Environmental Aid Association (DUH) has commissioned the exhaust testing the University of Bern in order. For the first time the data has now been obtained in actual operation, not only to the test. The result: The emission of carcinogenic soot and other pollutants is road traffic significantly higher than in the test scenario in the laboratory…." (Translated by Google Translate)

    Source: http://www.spiegel.de/auto/aktuell/deutsche-umwelthilfe-gefaehrliche-benziner-mit-direkteinspritzung-a-930663.html


    ALL PM2.5 (actually ALL air pollution) has been classified as a Group 1 carcinogen ("carcinogenic to humans") by IARC, not just diesel PM.

    Finally, a report of a very rigorous study of regulated and unregulated emissions from three 2010-compliant diesel truck engines has been recently released - Advance Collaborative Emissions Study (ACES) Phase 2 - http://www.crcao.org/reports/recentstudies2013/ACES%20Ph2/03-17124_CRC%20ACES%20Phase2-%20FINAL%20Report_Khalek-R6-SwRI.pdf. Both regulated emissions and over 300 unregulated emissions have been reduced to near or below detection levels in several different test duty cycles.

    Another Phase of the ACES study (Phase 3) has shown that test animals exposed to nearly continuous exposure to concentrated exhaust from a 2007-compliant diesel truck engine has shown little effect through 12 month (http://pubs.healtheffects.org/getfile.php?u=708) and preliminarily through the normal lifespan of the test animals (http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/ace044_greenbaum_2013_o.pdf - Slide #19). 2010-compliant diesel engines have emissions that are significantly reduced even from 2007-compliant engines.
     
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  17. wxman

    wxman Active Member

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    Actually, GrumpyCabbie, I'm perplexed by your adamant attack on diesel emissions.

    I thought I've seen posts from you highlighting how clean the inside of tailpipes of diesel cars you've seen were?
     
  18. GasperG

    GasperG Senior Member

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    Small passenger cars need a simple engine design that is "clean" by default and needs very little after treatment.

    Prius - problem solved ;)
     
  19. GrumpyCabbie

    GrumpyCabbie Senior Member

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    From somebody else who lives in an environment where diesels are used to excess.

    Funny how many from Europe where diesel smog is prevalent like the Prius and the Americans (in this thread) where diesel cars are as rare as manual transmissions are all pro diesel.

    I appreciate the science and theory of diesel emission reduction - in a laboratory, but in the real world diesel emission control isn't as good as it's made out. I have in the past mentioned the inside of the exhaust of some diesel cars being totally clean to the touch, but it's early days. Ask me again in 5 years time when these cars are 8 years old. If they're still clean, I'm a convert. If they're not, I'm not.

    I know from the taxi experience that emission control on a petrol is much simpler and generally more reliable. Diesel emission control adds a whole new level of complication.

    From what some of the posters above are saying, diesel is obviously the fuel of the future as it can be cleaned up better than a petrol. Well if that's the case, bring it on. Diesel will be cleaner than petrol? Great. Diesel cars for long runs and BEV's for local. Our infrastructure is all in place and people are used to diesels. Maybe the diesel fanboys were ahead of their time all along?
     
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  20. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    ^ Well said.

    Like I said.
    In the colonies?
    Passenger car diesels are a solution in search of a problem.