The Electric Car
in [Design]
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From: Eeyore on 8 Aug 2007 02:30 MooseFET wrote: > Don Lancaster <d...(a)tinaja.com> wrote: > > MooseFET wrote: > > > > > I think compressed air is a better way to go. > > > > Go for what? > > > > The energy density of compressed air is ludicrously low. > > Typically one sixth of lead acid or worse. 15 wh/l is hard to acheive. > > It is the energy per pound kilograms please. Pounds are used only in Myanmar (Burma), Liberia and oh yes, the USA. > not the energy per unit volume that matters. Others have seen that it is a > good light way to store energy > and get the power out quickly when needed. You can't say that in isolation. If the volume becomes excessive (which it does with compressed air) it's equally impractical. And don't forget the weight of the containment either (also a big problem - one of many - for hydrogen). Graham
From: Eeyore on 8 Aug 2007 02:31 MooseFET wrote: > Eeyore wrote: > > MooseFET wrote: > > > JosephKK <joseph_barr...(a)sbcglobal.net> wrote: > > > > Mark makol...(a)yahoo.com posted to sci.electronics.design: > > > > > > >> It seems to just argued against using any electric motors at all. > > > > > > > Yep, I think the small batteries and electric motor in the Prius > > > > > are there for only 2 reasons.. > > > > > > > 1) efficency gained by regenerative braking > > > > > 2) improve the acceleration so the ICE can be smaller also > > > > > improving the efficency. > > > > > > > If you had the small ICE without the acceleration boost provided > > > > > by > > > > > the electrics, the acceleration would be poor and people would > > > > > not like the "drivablility". > > > > > > > Intersting to note that a flywheel could provide the same > > > > > advantage. > > > > > > > In fact I tend to think of the battery and electric motor in the > > > > > Prius is just an electric implementation of a flywheel. > > > > > > Yes, and flywheels bring their own issues with changes yaw, pitch > > > > and roll. There will have to be space for the flywheel to spin not > > > > only during normal driving but the vehicle must not become a hazard > > > > if it rolls over in any direction or spins out. > > > > > I think compressed air is a better way to go. > > > > Compressed air power storage is horribly lossy. > > Not from what I've read. The problem is the pumps. No, the problem is physics and the various Gas Laws. > The Volvo Flygmotor busses used hydraulic pumps and motors but the energy > storage was compressed air. And where are they now ? Graham
From: Eeyore on 8 Aug 2007 02:37 John Larkin wrote: > Jim Thompson wrote: > > > >I'm getting 19MPG at 85MPH in my Q45 ;-) > > > I'm getting 18 MPG in my 5-cylinder Rabbit, driving to/from work on > the hills of San Francisco. I average about 4000 miles per year. Now that's where an EV really would score ! Graham
From: Eeyore on 8 Aug 2007 02:41 John Larkin wrote: > I'm soooo tired of seeing entire blocks of cars that are all grey and silver > and black. Yes, they're very bland / boring. I've had a couple that are 'silverish' but still have some colour in them. One was called 'platinum', my neighbour called it 'oyster'. It was very nice. Graham
From: MooseFET on 8 Aug 2007 09:26
On Aug 7, 8:10 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Tue, 07 Aug 2007 12:11:15 -0700, Jim Thompson > > > > <To-Email-Use-The-Envelope-I...(a)My-Web-Site.com> wrote: > >On Tue, 07 Aug 2007 11:36:32 -0700, James Arthur > ><dagmargoodb...(a)yahoo.com> wrote: > > >>On Aug 1, 6:11 am, MooseFET <kensm...(a)rahul.net> wrote: > >>> On Jul 31, 9:38 pm, JosephKK <joseph_barr...(a)sbcglobal.net> wrote: > > >>> > MooseFET kensm...(a)rahul.net posted to sci.electronics.design: > > >>> > > On Jul 31, 6:48 am, John Larkin > >>> > > <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >>> > >> On Mon, 30 Jul 2007 23:31:20 -0700, Richard Henry > > >>> > >> <pomer...(a)hotmail.com> wrote: > >>> > >> >On Jul 30, 8:25 pm, krw <k...(a)att.bizzzz> wrote: > >>> > >> >> In article > >>> > >> >> <1185850948.051175.139...(a)d30g2000prg.googlegroups.com>, > >>> > >> >> pomer...(a)hotmail.com says... > > >><snip> > > >>> > >> >> > OOHH!. Think of the children... > > >>> > >> >> > You sound like a leftist weenie. > > >>> > >> >> Not at all. Not "the" children. *HIS* children. There is a > >>> > >> >> difference. > > >>> > >> >> > Please explain again the more-efficient-at-higher-speed > >>> > >> >> > feature. > > >>> > >> >> It's entirely possible as was explained at the time. > > >>> > >> >It was bs then and it's bs now. All fancy gearing and ignition > >>> > >> >tricks will be overcome by the inevitability of the > >>> > >> >non-linearity of increase of air resistance with speed. > > >>> > >> The air resistance is highly nonlinear, cubic power:speed > >>> > >> roughly, whereas other losses are essentially independent of > >>> > >> speed. Every car will have an optimum speed for miles/gallon, and > >>> > >> it won't be zero. > > >>> > > It also won't be much over about 50MPH. It takes about 15 HP to > >>> > > push > >>> > > a modest sized car at 50MPH. The windage losses per mile run as > >>> > > just about the square of the speed. > > >>> > Not necessarily. My first new car got about 22 mpg at 55 mph and > >>> > about 26 mpg at 70 mph. Back then i had plenty of documentation to > >>> > back it up. Kinda funny, 70 mph occurred right the rmp torque > >>> > peak. It couldn't be a coincidence could it? > > >>> It was likely a combination of coincidence and something very wrong > >>> with the car. 22MPG at 55MPH is a horrid milage. This is very like > >>> the leaky fuel line case. > > >>FWIW, I've always gotten about 20% better than EPA-rated fuel economy, > >>by carefully optimizing my driving. > > >>I had been driving 55 mph, then even 50 mph in an attempt to improve > >>my Acura's mpg. Careful cross-country measurements show optimum fuel > >>economy to be 41mpg, which applies from 85 down to 65 mph. Going > >>slower reduces mpg. > > >>A gearhead pal offered a decent explanation of how providing the > >>engine with optimum load and RPM by going faster makes my particular > >>engine more efficient, making up for the windage loss... up to a > >>point, of course. > > >>Cheers, > >>James Arthur > > >I'm getting 19MPG at 85MPH in my Q45 ;-) > > > ...Jim Thompson > > I'm getting 18 MPG in my 5-cylinder Rabbit, driving to/from work on > the hills of San Francisco. I average about 4000 miles per year. That would also be a hard environment for a non-special purpose electric car. The very low speeds and a lot of starting on upgrades etc would make for a low range in an electric. Since your trip is to work and back, you can't be going far so an electric car would work for you. Far better would be to extend the cable car system. It takes a quite low energy input per person moved. It may be best if the Muni system was removed. From what I read in the news, it kills more people than it takes safely to their destination. |