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Thread: Chevy Volt priced at $41,000 before credit.

  1. #31
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    Start&Stop devices are now available on diesel cars as well, but the fact they came later than on petrol models, and that the size of batteries on standard cars keeps on growing, I'd suspect this system is more suitable on petrol cars. The engine is easier to start, requires less power (less pressure required), and there can be no turbo (a further obstacle) while still getting a good mileage.
    I should find again some data I put together about improvements on petrol and diesel cars when equipped with such systems.

    The reason why the engine is often turned off is mainly to achieve "extraordinary" CO2 figures. People don't really care if they are going to spend less counting both electricity and fuel, and no one is providing not only good estimates on electricity costs related to high voltage lines to charge the cars, and not even CO2 emissions related to the electricity required to run/charge the car.

    Talking about temperatures, diesel takes a little more to reach their operating temperatures mainly because the engine has ticker walls and parts, and also because and it is even less efficient during the first cycles because the fuel won't vaporize (something less problematic with petrol). This will also affect the turbo's efforts.

    Eventually, I'm not sure if temperatures would drop significantly so to affect a diesel ICE's efficiency, but it would again add complexity to an already complex (and therefore expensive for the end user) system.

    It doesn't really surprise me that PSA is trying (according to their statements) to enter the hybrids market with a diesel ICE. Relying mainly on EU sales, their engines production is probably biased towards diesel engines which they are also pretty good at. They have always been more than proud about their particulate filters, and in a hybrid system things would be even better.
    On the other hand, they may be aware that diesel engines won't have a very long life ahead of them, so trying to improve this time with some electric motors is also a sensible idea to save updates to petrol based systems for later on.
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  2. #32
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    While you are looking for stuff, it's been a long time but you don't happen to have a themodynamic cycle comparison of a turbo vs non-turbo motor of the same power? I've been trying to remember the details of how a turbo makes a gasoline motor more efficient. I can think of lots of reasons why a smaller displacement turbo would be more efficient than a larger motor of the same power but most of those reasons are not specific to the motor but are related to the car. Things like longer top gear thus lower RPM. Think about it in terms of comparing say a 1997 SAAB 900 2.0T vs 2.3 non-T. It's been a while since I've looked at my themo cycles.

  3. #33
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    Quote Originally Posted by aiasib View Post
    Wow, it looks NOTHING like the concept.
    No kidding, that's what I was just gonna say.
    Last edited by Sledgehammer; 08-02-2010 at 07:13 PM.

  4. #34
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    That's not at all surprising. The concept was like most other concepts, very out there. It also wasn't at all aerodynamic. Lutz said it was better in reverse!

  5. #35
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    Quote Originally Posted by culver View Post
    While you are looking for stuff, it's been a long time but you don't happen to have a themodynamic cycle comparison of a turbo vs non-turbo motor of the same power? I've been trying to remember the details of how a turbo makes a gasoline motor more efficient. I can think of lots of reasons why a smaller displacement turbo would be more efficient than a larger motor of the same power but most of those reasons are not specific to the motor but are related to the car. Things like longer top gear thus lower RPM. Think about it in terms of comparing say a 1997 SAAB 900 2.0T vs 2.3 non-T. It's been a while since I've looked at my themo cycles.
    Not putting numbers in, the existence of the Turbo is already recycling the energy in the exhaust gas that would otherwise just be wasted into helping the engine do work, so I'd imagine you are bumping the efficiency up regardless...

    Side note, the MSRP of this thing is probably less important than the Lease cost of $350/month. That's about "normal" for a family car if not a little bit on the high side. But for someone looking at this kind of product they might just take the plunge since its not a significant jump...
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  6. #36
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    Quote Originally Posted by RacingManiac View Post
    Not putting numbers in, the existence of the Turbo is already recycling the energy in the exhaust gas that would otherwise just be wasted into helping the engine do work, so I'd imagine you are bumping the efficiency up regardless...

    Side note, the MSRP of this thing is probably less important than the Lease cost of $350/month. That's about "normal" for a family car if not a little bit on the high side. But for someone looking at this kind of product they might just take the plunge since its not a significant jump...
    That energy isn't recycled for free. In this case I'm specifically interested in the thermo cycle tables. I originally started down a combustion engineering track but that was years ago and I have forgotten more than I care to admit. Well that and I was don't gas turbine vs piston engines.

  7. #37
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    I'd imagine the benefit is similar. In steam turbine or something you use the exhaust heat to run the regen cycle to pre-heat the steam. The Turbo pre-compresses the intake charge to up the volumetric efficiency. One recycles heat, the other recycles kinetic energy of the exhaust flow. Same effect also applies I think a gas turbine/jet engine....
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  8. #38
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    The turbo cycle didn't look like a bottoming cycle (where use use waste heat to run a second steam cycle for instance). Turbos are also quite different than the gas turbine cycle. I just don't remember exactly what they looked like.

  9. #39
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    Apparently my thermo cycles book has been left in Modena. I'm in "summer break mode" since three days, but I'll look if I can dig out some old notes here at parents'.
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  10. #40
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    Besides, the Volt can use regular gazoline:
    2011 Chevrolet Volt has knock sensor, can run on regular gas Autoblog
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  11. #41
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    I've seen so many cases were someone takes a snippet about the Volt and turns it into something it's just not. We have the premium gas bit. No surprise the car is tuned to run on the fuel that gives maximum economy but can also use less grades. We had people raise bloody hell that the on board motor wouldn't recharge the batteries. Never mind that if you drive 40 miles then let the gas motor recharge the batteries you might as well just create a series hybrid and screw the EV part of the system. Finally after GM said the gas motor would recharge the batteries people said the car would be limited to 80hp (or what ever the gas motor is) once you drove the 40 miles. That's stupid because GM has always said the car would operate as a series hybrid in extended range mode.

    It seems the biggest issue GM is having is making sure people just have their facts right.

  12. #42
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    Quote Originally Posted by culver View Post
    It seems the biggest issue GM is having is making sure people just have their facts right.
    could that be because people may think that in the past GM was having great problems of having their facts right?
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  13. #43
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    Quote Originally Posted by henk4 View Post
    could that be because people may think that in the past GM was having great problems of having their facts right?
    Certainly when it comes to talking about reliability GM hasn't done well. However, in this case we are talking about people just being wrong. GM actually has a pretty good record of not stretching the technical truth. Look at GM's HP testing vs Toyota. With the new stricter testing standards GM's numbers didn't change. Toyota's almost all dropped.

  14. #44
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    I honestly thought it was dead after the economic downturn. But not now....
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  15. #45
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    So apparently the Volt really is a glorified hybrid.

    In extreme discharge conditions, the engine will kick in to power the wheels.

    How much did GM lie to sell this car? It's not like I'm out to get this car, but pretty much it is a lie of omission.

    Chevy Volt and Nissan Leaf Fuel Ratings a Struggle for E.P.A. - NYTimes.com

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