The Electric Car
in [Design]
|
From: Spehro Pefhany on 1 Aug 2007 08:57 On Tue, 31 Jul 2007 23:09:20 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Wed, 01 Aug 2007 00:45:24 -0500, Spehro Pefhany ><speffSNIP(a)interlogDOTyou.knowwhat> wrote: > >>On Tue, 31 Jul 2007 21:29:24 -0700, the renowned John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Tue, 31 Jul 2007 18:08:26 -0700, MooseFET <kensmith(a)rahul.net> >>>wrote: >>> >>>>On Jul 31, 8:19 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- >>>>Web-Site.com> wrote: >>>>> On Tue, 31 Jul 2007 08:14:21 -0700, John Larkin >>>>> >>>>> >>>>> >>>>> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>> >On Tue, 31 Jul 2007 14:37:31 +0000, Guy Macon >>>>> ><http://www.guymacon.com/> wrote: >>>>> >>>>> >>Jim Thompson wrote: >>>>> >>>>> >>>I don't ever recall saying "more-efficient-at-higher-speed". >>>>> >>>>> >>>But I guess it WOULD depend on your definition. The engine is >>>>> >>>optimized right around 3000RPM (85MPH), but external drag is higher. >>>>> >>>>> >>Assuming that "optimized" means maximum efficiency as opposed >>>>> >>to maximum power or torque, wouldn't it be more efficient at >>>>> >>3000 RPM in first gear? >>>>> >>>>> >>Part of me thinks about the far lower drag and says that it >>>>> >>would. Part of me thinks about those pistons moving up and >>>>> >>down more times per mile and sucking in about the same amount >>>>> >>of fuel per cycle and says that it wouldn't. Maybe it needs >>>>> >>an engine sized for 3000 RPM in first gear to make it work? >>>>> >>>>> >>Also, I can't prove it, but I suspect that hard accelerating >>>>> >>to some speed (don't know how fast) and then shutting down >>>>> >>the engine and coasting down, then repeating, gives the >>>>> >>maximum fuel economy. >>>>> >>>>> >Interesting curve: >>>>> >>>>> >http://www.fueleconomy.gov/feg/driveHabits.shtml >>>>> >>>>> >And it is reasonable to also factor in the value of your time. >>>>> >>>>> >John >>>>> >>>>> "Remove excess weight"... don't give a leftist weenie a ride ;-) >>>> >>>>At those speeds it is drag not weight that matters. You shouldn't >>>>wear a dress while driving. >>> >>>You get the best mileage if you wear nothing at all. >> >>I suspect Spandex is better than nothing. More slippery than hairy >>surfaces and it could prevent the energy-sapping oscillation of fatty >>and/or dangly bits. > > >Well, I suppose some people are more viscous than others. > > >> >>Interesting that modern hybrids apparently get better gas milage in >>city driving rather than highway. > >We have a friend who bought a Toyota hybrid. But hauling all those >batteries up and down the hills here apparently isn't efficient... her >mileage is mediocre. The battery pack is actually pretty tiny on the Prius (40kg) 6.5AH at 273VDC, which works out to 3% of the curb weight. http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/2a_2002_01_1962.pdf >>Eg. Prius 60mpg city, 51mpg highway > >People don't buy Prius' to save gas, they buy them to be hip and >stylish. So instead of smog, we have clouds of smug. > >John Yes. _South Park_ dubbed it the "Toyota Pius". My calculations indicate the payback to be marginal on hybrids, even with a $4K government subsidy, so long as gas remains around $3US/US gallon, and the Prius yields significantly better mileage than, say, the hybrid Camry. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff(a)interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
From: MooseFET on 1 Aug 2007 09:11 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... > > >> >> > On Jul 30, 7:20 pm, Jim Thompson > >> >> > <To-Email-Use-The-Envelope-I...(a)My- Web-Site.com> wrote: > >> >> > > On Mon, 30 Jul 2007 19:12:03 -0700, Richard Henry > > >> >> > > <pomer...(a)hotmail.com> wrote: > >> >> > > >On Jul 30, 5:48 pm, Jim Thompson > >> >> > > ><To-Email-Use-The-Envelope-I...(a)My- Web-Site.com> wrote: > >> >> > > >> On Mon, 30 Jul 2007 17:30:01 -0700, "J.A. Legris" > > >> >> > > >> >- I said fuel consumption will never decrease much > >> >> > > >> >unless cars are much lighter, but even radically > >> >> > > >> >lighter vehicles are no long-term solution on this > >> >> > > >> >overpopulated planet > > >> >> > > >> Amen! I keep telling people that, and they look at me > >> >> > > >> like I'm some kind of idiot. > > >> >> > > >You have also told us how you like to drive your big > >> >> > > >import illegally fast and tried to rationalize it by > >> >> > > >claiming that among the vehicle's luxury features is that > >> >> > > >it runs more efficiently at high speed. > > >> >> > > I didn't rationalize anything. However I do agree that > >> >> > > leftist weenies should be taxed more heavily to support my > >> >> > > excesses ;-) > > >> >> > > And I certainly have no problem with YOU driving a tin > >> >> > > can, just NOT my children and grandchildren ;-) > > >> >> > 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.
From: MooseFET on 1 Aug 2007 09:17 On Jul 31, 10:45 pm, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Tue, 31 Jul 2007 21:29:24 -0700, the renowned John Larkin > > > > <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >On Tue, 31 Jul 2007 18:08:26 -0700, MooseFET <kensm...(a)rahul.net> > >wrote: > > >>On Jul 31, 8:19 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- > >>Web-Site.com> wrote: > >>> On Tue, 31 Jul 2007 08:14:21 -0700, John Larkin > > >>> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >>> >On Tue, 31 Jul 2007 14:37:31 +0000, Guy Macon > >>> ><http://www.guymacon.com/> wrote: > > >>> >>Jim Thompson wrote: > > >>> >>>I don't ever recall saying "more-efficient-at-higher-speed". > > >>> >>>But I guess it WOULD depend on your definition. The engine is > >>> >>>optimized right around 3000RPM (85MPH), but external drag is higher. > > >>> >>Assuming that "optimized" means maximum efficiency as opposed > >>> >>to maximum power or torque, wouldn't it be more efficient at > >>> >>3000 RPM in first gear? > > >>> >>Part of me thinks about the far lower drag and says that it > >>> >>would. Part of me thinks about those pistons moving up and > >>> >>down more times per mile and sucking in about the same amount > >>> >>of fuel per cycle and says that it wouldn't. Maybe it needs > >>> >>an engine sized for 3000 RPM in first gear to make it work? > > >>> >>Also, I can't prove it, but I suspect that hard accelerating > >>> >>to some speed (don't know how fast) and then shutting down > >>> >>the engine and coasting down, then repeating, gives the > >>> >>maximum fuel economy. > > >>> >Interesting curve: > > >>> >http://www.fueleconomy.gov/feg/driveHabits.shtml > > >>> >And it is reasonable to also factor in the value of your time. > > >>> >John > > >>> "Remove excess weight"... don't give a leftist weenie a ride ;-) > > >>At those speeds it is drag not weight that matters. You shouldn't > >>wear a dress while driving. > > >You get the best mileage if you wear nothing at all. > > I suspect Spandex is better than nothing. More slippery than hairy > surfaces and it could prevent the energy-sapping oscillation of fatty > and/or dangly bits. > > >John > > Interesting that modern hybrids apparently get better gas milage in > city driving rather than highway. > > Eg. Prius 60mpg city, 51mpg highway > > http://www.toyota.com/prius/specs.html This is as you would expect if they are making good use of the energy in the fuel.
From: AZ Nomad on 1 Aug 2007 09:17 On Sat, 28 Jul 2007 16:34:44 -0700, gyansorova(a)gmail.com <gyansorova(a)gmail.com> wrote: >Don't give me your problems! Give me your solutions!! What's the >answer when the oil runs out? Where do you think the electricity comes from? An electricity well?
From: MooseFET on 1 Aug 2007 09:22
On Jul 31, 9:12 pm, krw <k...(a)att.bizzzz> wrote: > In article <1185930451.854228.138...(a)x35g2000prf.googlegroups.com>, > kensm...(a)rahul.net says... > > > > > On Jul 31, 7:21 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- > > Web-Site.com> wrote: > > > On Mon, 30 Jul 2007 20:02:28 -0700, Richard Henry > > > > <pomer...(a)hotmail.com> wrote: > > > >On Jul 30, 7:20 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- > > > >Web-Site.com> wrote: > > > >> On Mon, 30 Jul 2007 19:12:03 -0700, Richard Henry > > > > >> <pomer...(a)hotmail.com> wrote: > > > >> >On Jul 30, 5:48 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- > > > >> >Web-Site.com> wrote: > > > >> >> On Mon, 30 Jul 2007 17:30:01 -0700, "J.A. Legris" > > > > >> >> >- I said fuel consumption will never decrease much unless cars are > > > >> >> >much lighter, but even radically lighter vehicles are no long-term > > > >> >> >solution on this overpopulated planet > > > > >> >> Amen! I keep telling people that, and they look at me like I'm some > > > >> >> kind of idiot. > > > > >> >You have also told us how you like to drive your big import illegally > > > >> >fast and tried to rationalize it by claiming that among the vehicle's > > > >> >luxury features is that it runs more efficiently at high speed. > > > > >> I didn't rationalize anything. However I do agree that leftist > > > >> weenies should be taxed more heavily to support my excesses ;-) > > > > >> And I certainly have no problem with YOU driving a tin can, just NOT > > > >> my children and grandchildren ;-) > > > > >OOHH!. Think of the children... > > > > >You sound like a leftist weenie. > > > > >Please explain again the more-efficient-at-higher-speed feature. > > > > I don't ever recall saying "more-efficient-at-higher-speed". > > > > But I guess it WOULD depend on your definition. The engine is > > > optimized right around 3000RPM (85MPH), but external drag is higher. > > > If you shift to a lower gear, 3000 RPM is at a lower speed. If there > > isn't an issue that is well modeled by a fuel leak, the milage would > > improve. > > Ever consider that transmissions aren't equally efficient in all > gears Yes but he didn't report he was driving with a faulty one. > and perhaps the over-drive locked-up may be a tad more > efficient than the lower gears? A tad but not enough to make the difference. The energy per mile increases as the square of the speed. > There is also work done just > spinning the engine. Me thinks you're wrong. I think not. > > -- > Keith |