The Electric Car
in [Design]
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From: Guy Macon on 1 Aug 2007 22:01 AZ Nomad wrote: >Where do you think the electricity comes from? An electricity well? It comes from an open-pit electricity strip-mine. -- Guy Macon <http://www.guymacon.com/>
From: Don Klipstein on 1 Aug 2007 22:02 In <1186019741.273364.202210(a)d30g2000prg.googlegroups.com>, MooseFET wrote: >On Aug 1, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat wrote: >> 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. Energy per mile is proportional to force of drag so both are square laws. The cubic law is power used to overcome drag - airspeed squared times groundspeed. - Don Klipstein (don(a)misty.com)
From: MooseFET on 1 Aug 2007 22:02 On Aug 1, 10:28 am, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Wed, 01 Aug 2007 10:23:13 -0700, Jim Thompson > > > > <To-Email-Use-The-Envelope-I...(a)My-Web-Site.com> wrote: > >On Wed, 01 Aug 2007 08:46:53 -0700, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >>On Wed, 01 Aug 2007 08:26:13 -0700, Jim Thompson > >><To-Email-Use-The-Envelope-I...(a)My-Web-Site.com> wrote: > > >[snip] > > >>>You need to look at engine horsepower and torque versus RPM as well. > > >>Don't tell me what I need to do. > > >Eh? Didn't get any last night, John? You sure are cranky ;-) > > >>>Drag DOES depend on body shape. > > >>Aero drag goes up roughly with the square of speed for most shapes. > >>The question is where the v^2 thing starts to dominate. The answer, > >>for most cars, seems to be upwards of 55 MPH. Below that, other things > >>seem to matter. > > >>John > > >I think, if you will follow my advice, see the horsepower peak in that > >region as well. > > > ...Jim Thompson > > I wonder at what speed a 500HP 'vette is most efficient? ;-) When its in the shop and you take a taxi home. > > 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: Guy Macon on 1 Aug 2007 22:07 Spehro Pefhany wrote: >I wonder at what speed a 500HP 'vette is most efficient? ;-) You get 500HP out of your Chevette? -- Guy Macon <http://www.guymacon.com/>
From: Eeyore on 1 Aug 2007 22:53
MooseFET wrote: > Eeyore wrote: > > John Larkin wrote: > > > Spehro Pefhany wrote: > > > > > >>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. > > > > > >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. > > > > > Both hybrids would get far better mileage if the batteries, the > > > electrics, and all the fancy controls were dumped. What's left would > > > be a small, light, slippery, ugly car with a small engine. All you'd > > > give up is acceleration and the questionable advantage of regenerative > > > braking, a small price to pay for dumping the batteries. > > > > In city driving it's regenerative braking that can make a huge difference. The > > complexity of shoving electrical and ICE motive power through some combined > > transmission seems plain daft though. The series hybrid (in which the ICE simply > > recharges a battery) seems far more sensible all round. > > No, I disagree. The dual electrical machine design beats the series > system hands down. Having the engine go straight to the wheels when > it makes sense to do so makes the demand on the electrical system way > less. Why's that an advantage ? It also means you can't have 'meaningful' true electric only operation of it, plus it requiresa gearbox which otherwise may not be needed at all. Graham |