The Electric Car
in [Design]
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From: Spehro Pefhany on 1 Aug 2007 15:30 On Wed, 01 Aug 2007 20:18:45 +0100, Eeyore <rabbitsfriendsandrelations(a)hotmail.com> wrote: > > >Spehro Pefhany wrote: > >> Ren� 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-buy-a-diesel-186004.php >> >> 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? 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: Eeyore on 1 Aug 2007 15:46 Spehro Pefhany wrote: > Eeyore wrote: > >Spehro Pefhany wrote: > >> Ren� 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-buy-a-diesel-186004.php > >> > >> 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. > > > How about noisy/smelly? I got caught behind a smelly one the other day. It was a 1996 or thereabouts model and seemed not to be in the best state of tune (it was smoking a bit too). You get petrol cars that are equally offensive. Mostly diesels don't seem to be very smoky or smelly these days although buses often seem to be rather poor. As for noise, some seem worse than others. The best examples are quite quiet now. Graham
From: Rich Grise on 1 Aug 2007 18:40 On Wed, 01 Aug 2007 20:18:45 +0100, Eeyore wrote: > Spehro Pefhany wrote: >> Ren� 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-buy-a-diesel-186004.php >> >> 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. I won "designated driver" one time, and drove this guy's Mercedes 300D. What a pig! Had horrendous blind spots, and went 0-60 in about 10 minutes. ;-) Thanks, Rich
From: MooseFET on 1 Aug 2007 21:42 On Aug 1, 9:10 am, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> 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.
From: MooseFET on 1 Aug 2007 21:45
On Aug 1, 6:27 am, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Wed, 01 Aug 2007 06:17:26 -0700, MooseFET <kensm...(a)rahul.net> > wrote: > > > > >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. > > Sure. It's interesting to see that they've actually achieved it, with > significant mileage improvment to boot, in a practical production car. > I suspect that many of us in this news group such as those who have done things like DC-DC converters would say that any car that doesn't do that is an example of bad design. The auto industry is still stuck largely in the stone age. They are a little like the folks who club dinner but have a transistor radio. > 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 |