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Hybrid Vehicles Why Tesla wanna go Hybrid when is already 100% electric?
22 messages, Last post on Mar 14, 2009 at 8:55 AM
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Replying to: gwmort (May 28, 2008 7:17 am)
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Replying to: coldcranker (Dec 29, 2008 9:30 am) Everyone seems to be focussed solely on the current low cost of each Kilowatt hour from the PLUG....Subject to change with NO notice. Build a smallish CNG fueled SuperChargered engine, Miller Cycle engine, that ALWAYS operates at its most optimal speed, at or near WOT(minimized pumping losses), and I have no doubt that one could OUTPERFORM the commercial grid's power generation, distribution losses/costs and adverse environmental effects.
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Replying to: wwest (Dec 29, 2008 6:28 pm) Back on topic, however, it would be a good idea for Tesla to be looking at batteryfree series hybrids so that they can leverage their electronic powertrain technology towards other applications that don't include long strings of Li-ion just in case they get locked out of the large format battery Li-ion business upstream. I am sure there are motorcycle engine manufacturers around with the knowhow to develop 100Hp for a highspeed genset application using a lot less parts than currently available 4 cyl automobile engines employ. Modern automobile engines still carry a lot of baggage to cope with the clutch coupled multi-ratio transmission that, save for the Prius, is used exclusively today.
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Replying to: toyolla2 (Dec 30, 2008 11:17 am) NOT...!! The "HOG" cycles use engine technology from the 1930's and that's the way the owners like/want it. On the other end of this spectrum is 'cycle engines that run at 12-18,000 RPM. So it's the aircraft engine manufacturing company's that are more likely to have the expertise for this, CONSTANT RPM, HIGH output power at relatively LOW RPM, for hour upon hour and decent FE to boot. What is needed for road-going engines, at the "BASE", really amounts to TWO engines, a small displacement but HIGHLY efficient ICE for simply cruising, and a HUGE ICE (battery in the current crop of 0-60 oriented hybrids) to yield the acceleration levels that US owners seem to value so highly. The obvious answer to that conundrum is a hybrid, total battery road power but with a small high efficient, probably constant speed, fossil fuel (CNG) engine/generator with the ability to supply just enough electricity to allow the electric drive motor(s) to move the vehicle along at reasonable road speeds and simultaneously recharge the battery in order to keep a RESERVE charge available for use as a SuperCharger. Looks to me like Tesla may be on to something.
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Replying to: wwest (Jan 02, 2009 9:04 am) One thing people often forget is that when you charge a battery, you lose about half the energy to heat, analagous to spilling juice on the floor sloppily. |
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Replying to: wwest (Jan 02, 2009 9:04 am) the 2009 Honda CRF450R motorcycle sports a single cylinder 449cc capable of 56Hp  8500rpm. The whole bike weighs 200+ lbs. The engine by itself sans gearbox/clutch probably weighs around 40lbs. This happens to be exactly twice as powerful as the Prius battery, which Gagrice reckons to weigh in at about 90lbs. The underlying point is to say that for mobile applications These last two points are, of course, covered by Tesla. As I see it the aim of Tesla is to produce that 4 second to 60 rush without the unreliabilty and NVH of V12 engines. But would a pair of these motorcycle engines accomplish this task ? I am not saying that, but just consider....... The pre- production EV1 acheived 60mph in 8 seconds with just 114Hp and 1175lbs of lead acid battery. If the weight delta by dispensing with these was factored in, an overall saving of 1000lbs might result. This could yield a figure of six seconds to 60. As I recall, the EV1 didn't reach full power until 42mph. The superior ampacity of Tesla's inverter could lower that point to 20mph and further improve on this figure. Obviously I am not interested in pure electric cars, only the technology they present in moving us away from the use of large mechanical engineering systems of current vehicles. Need I say more ? T2
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Replying to: toyolla2 (Feb 02, 2009 4:25 am) 8500RPM.... The best way to make us of that "power" is to provide a "power" accumulator so that when the engine runs it runs ONLY at the most optimum RPM. In the Tesla that accumulator is called a "battery".
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Replying to: wwest (Feb 02, 2009 11:10 am) Respectfully but your mind is locked up with this obsession for efficiency as a primary need for a powertrain. Having looked at this for quite a few years, my mind changed from efficiency towards an obsession for efficacy instead. Since acceleration is such a small part of the driving cycle - it lasts only a few seconds - we don't have to be concerned with peak efficiency at that time. It's what comes afterwards that concerns me. Case in point. Consider If I accelerate to 60mph in eight seconds and then drive a further three miles at that speed. But no accumulator battery is used at all, only a direct gasoline-electric powertrain. Then what you are saying is this, that what happens during those first 117yds is going to significantly affect my overall fuel economy for the whole three mile trip you are saying that what happens in 1/16mile will affect the next three miles. Put another way the first 2% of the trip will significantly ruin any fuel economy I might gain with that small engine over the whole trip !! Quite frankly, I don't see it. To go with your idea instead, I would assume, is to suggest the additional installation of a couple of Prius battery systems (weighing 180lbs total and costing $5000 total plus significant bulk)) to supply 50Hp during acceleration in order that I can limit my engine to run at its peak thermal efficiency which may occur at around only 15Hp ? Oh and by the way, let's conveniently forget that there is a continuous tire rolling resistance loss of humping that 180lbs of "boutique energy storage" around the streets at 60mph of at least 115watts !! -wwest I have limited time to hammer my points home so it'll be interesting to see how much of this post you will ignore. T2
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Replying to: toyolla2 (Feb 03, 2009 2:06 am) The add a battery ("accumulator") to fulfill the need for power surges above the average. Permanent magnet rotor AC synchronous electric motor/generators provide EXCELLENT capability in this regard. The ICE only runs if the battery SOC gets low enough.... The way I see it the "fly" in your "ointment" is that US drivers have grown used to upwards of 200HP for acceleration when all that is needed for simply cruising along at a constant speed might be as little as 25-30HP. That's HUGE operational range for a fossil fuel engine to be made efficient across. Spoiled, we are. Maybe a 40,000 PSI hydraulic pump/accumulator and a few gallons of ATF.
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