The Electric Car
in [Design]
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From: MooseFET on 1 Aug 2007 21:47 On Aug 1, 11:07 am, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Wed, 01 Aug 2007 18:44:25 +0100, Eeyore > > > > <rabbitsfriendsandrelati...(a)hotmail.com> wrote: > > >"René" wrote: > > >> On Wed, 01 Aug 2007 17:11:38 +0100, Eeyore > >> <rabbitsfriendsandrelati...(a)hotmail.com> wrote: > > >> >The official US figures don't agree with you. > >> >http://www.fueleconomy.gov/feg/noframes/20801.shtml > > >> >Graham > > >> OK you win :-) > >> not sure what are the export models shown here. > >> I was led to believe that smaller engined models could make it. > > >> (not even counting the energy in making the car!) > > >> Anyway, the "3 liter Lopo" (smaller brother of the Golf, designed for > >> economy - 4 person 5 door car) does 70 mpg. > > >I think you mean the 3 CYLINDER Lupo. It has a 1.2 litre turbodiesel engine. > >http://en.wikipedia.org/wiki/Volkswagen_Lupo > > >Graham > > 3-cylinder? Well, if you want real economy, an electric scooter with > SLA battery charged from a SMPS brick is about as far as you can go. Take a modern bike and add a good electric motor and battery and it will do even better.
From: MooseFET on 1 Aug 2007 21:49 On Aug 1, 12:09 pm, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Wed, 01 Aug 2007 20:19:03 +0200, René <rjz~REMO...(a)xs4all.nl> > wrote: > > > > >On Wed, 01 Aug 2007 18:44:25 +0100, Eeyore > ><rabbitsfriendsandrelati...(a)hotmail.com> wrote: > > >>I think you mean the 3 CYLINDER Lupo. It has a 1.2 litre turbodiesel engine. > >>http://en.wikipedia.org/wiki/Volkswagen_Lupo > > >It is indeed a confusing name. > >The "3 liter" is supposed to express the fact that it consumes less > >than 3 litres / 100 km. It is a special edition of the Lupo with > >lightened interior and skinny tyres. > > >The "real life" Priusses (Priae, Prii - whatever) we have here do > >15...18 km to a litre (no documentation, asking real life owners on > >local phora), a figure that is easily beaten by a average diesel car. > > >This is overall use. In city use (stop & go) the Prius may have a real > >advantage. > >I do like the hybrid technology - but I wait for the figures to > >improve. > > >I can imagine e.g. a light 2 stroke diesel, operating in its most > >efficient fixed rpm, driving a generator / accu combo; wheels driven > >by electrics only - may have a better yield. > > Don't diesel's have to be heavier to support the higher compression > ratio? They usually are bigger and heavier but that is partly because when you are designing the engine for a train you don't worry about weight. The forces in a high performance gas engine are higher than in a diesel.
From: MooseFET on 1 Aug 2007 21:53 On Aug 1, 12:30 pm, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Wed, 01 Aug 2007 20:18:45 +0100, Eeyore > > > > <rabbitsfriendsandrelati...(a)hotmail.com> wrote: > > >Spehro Pefhany wrote: > > >> René wrote: > > >> >I can imagine e.g. a light 2 stroke diesel, operating in its most > >> >efficient fixed rpm, driving a generator / accu combo; wheels driven > >> >by electrics only - may have a better yield. > > >> Don't diesel's have to be heavier to support the higher compression > >> ratio? > > >Typically they are. They need to be stronger rather than heavier really. > > >> >Somehow I distrust the factory milage figures. Makes me think of PMPO > >> >power.. > > >> >http://jalopnik.com/cars/news/classic-top-gear-the-prius-kinda-blows-.... > > >> I trust the test figures in a comparative sense. OTOH, I've not driven > >> a diesel that wasn't smelly, noisy and with crappy performance > >> compared to a gas engine. We won't easily put up with that sort of > >> thing here, nor is the lack of diesel pumps conducive to adoption. And > >> yes, I've driven a modern mid-size (VW Passat) diesel in several > >> European countries. > > >I drove a Peugeot 1.9 turbo diesel as long ago as 1988. It was pretty brisk. Performance seem to > >be less of an issue with diesels these days although they don't rev as fast. > > >Graham > > How about noisy/smelly? The new ones are nearly odorless. The ball in a coffee can sound is a lot quieter on the new ones too. One of the companies has an experimental engine that uses a cute trick to refine extra oxygen out of the air and add it to the intake. This raises the burn temperature enough to eat up all the bad stuff. > > Best regards, > Spehro Pefhany > -- > "it's the network..." "The Journey is the reward" > sp...(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 21:55 On Aug 1, 8:33 am, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Wed, 01 Aug 2007 08:26:13 -0700, Jim Thompson > > > > <To-Email-Use-The-Envelope-I...(a)My-Web-Site.com> wrote: > >On Wed, 01 Aug 2007 07:15:06 -0700, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >>On Wed, 01 Aug 2007 06:22:36 -0700, MooseFET <kensm...(a)rahul.net> > >>wrote: > > >>>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. > > >>Not in this graph: > > >>http://www.fueleconomy.gov/feg/driveHabits.shtml > > >>I've seen a few other mpg-vs-speed curves, and they all look similar. > >>Looks like aerodynamic drag starts to seriously kick in above 55 MPH. > > >>John > > >You need to look at engine horsepower and torque versus RPM as well. > > >Drag DOES depend on body shape. > > > ...Jim Thompson > > For a given shape, at automotive speeds, I think there is a square law > relationship between air speed and drag. No thats a cubic law. The energy per mile is the square law one.
From: MooseFET on 1 Aug 2007 22:01
On Aug 1, 9:21 am, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> wrote: > Spehro Pefhany wrote: > > Jim Thompson wrote: > > > John Larkin wrote : > > > >>http://www.fueleconomy.gov/feg/driveHabits.shtml > > > >>I've seen a few other mpg-vs-speed curves, and they all look similar. > > >>Looks like aerodynamic drag starts to seriously kick in above 55 MPH. > > > >>John > > > >You need to look at engine horsepower and torque versus RPM as well. > > > >Drag DOES depend on body shape. > > > > ...Jim Thompson > > > For a given shape, at automotive speeds, I think there is a square law > > relationship between air speed and drag. > > You are correct at higher speeds. The relationship isn't simple it seems.http://en.wikipedia.org/wiki/Drag_(physics) > > Drag coefficient can make collosal differences too.http://en.wikipedia.org/wiki/Drag_coefficient > > Unfortunately current US styling (the trend for truck like 'slab fronts' ) is producing > cars with greater rather than lesser drag. The shape of the back controls the drag more than the shape of the front. This is why the shape gets tot he full width fairly quickly and then slowly tapers to the back. > > The current hybrids also use skinny tyres to reduce rolling resistance. I hate to think > of the adverse effect on road holding. There is basically no difference in the traction. Wide tires look cool but below a certain amount of force per unit area of rubber give no traction advantage. The traction loss in thing tires is because the force on the surface is high enough to rip bits of the rubber or the road loose. They modern materials in the tires are less subject to this problem. The cars we are talking about are quite light too. > > Graham |