The Electric Car
in [Design]
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From: Jim Thompson on 2 Aug 2007 22:40 On Fri, 03 Aug 2007 00:47:16 GMT, JosephKK <joseph_barrett(a)sbcglobal.net> wrote: >Eeyore rabbitsfriendsandrelations(a)hotmail.com posted to >sci.electronics.design: > >> [snip] > >> I know American roads don't have corners (or at least >> from the way US cars drive you'd think that was the case) but we >> do here. > >We have them on residential streets. ;^) > >> >> Which reminds me... why do Americans seem to want such big engined >> over-powered cars when most of them fall off the road so easily if >> you use it ? Is it just a macho thing ? >> >> >> Graham Some of us own cars that can negotiate freeway ramps posted as 45MPH at double that speed with nary a tire squeal ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | America: Land of the Free, Because of the Brave
From: Spehro Pefhany on 2 Aug 2007 23:42 On Fri, 03 Aug 2007 02:57:46 +0100, the renowned Eeyore <rabbitsfriendsandrelations(a)hotmail.com> wrote: > > >Mark wrote: > >> > >> > 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. > >A flywheel would be so heavy as to make the car undriveable too. Depends on material strength. http://en.wikipedia.org/wiki/Flywheel#Physics http://en.wikipedia.org/wiki/Flywheel_energy_storage > Not to mention the gyroscopic action ! > >Graham And possible explosive release of energy. 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 2 Aug 2007 22:51 JosephKK wrote: > Eeyore rabbitsfriendsandrelations(a)hotmail.com posted > > MooseFET wrote: > >> Eeyore wrote: > >> > >> > 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. > > > > I'm not talking about traction, I'm talking about road holding / > > handling. > > And just how, exactly, do you separate the two (dealing with tires > only)? Both are ultimately limited by friction limits. Skinny tyres don't corner very well. Mind you, when the greenies get the guy with a red flag back in front of every car that'll be less of a problem. Graham
From: Eeyore on 2 Aug 2007 23:12 MooseFET wrote: > Eeyore wrote: > > MooseFET wrote: > > > On the highway, the engine gets connected directly to the wheels. > > > This takes the sosses of the electric machines out of the picture. > > > > What losses ? Electric motors are highly efficient. > > Yes exactly. The losses in the electric motors. They should be very low. Traction motors can be 90% efficient. > > > It also allows the engine and both motors to be used for passing power. > > > > At the cost and complexity of requiring a transmission. I just don't see any sense in it. > > It gives about 15% better fuel economy on the highway and about double > the merging power. Better than ..... what ? Double compared to .... what ? Scotch mist ? Graham
From: Eeyore on 2 Aug 2007 23:14
Jim Thompson wrote: > JosephKK wrote: > >Eeyore rabbitsfriendsandrelations(a)hotmail.com posted > > > >> I know American roads don't have corners (or at least > >> from the way US cars drive you'd think that was the case) but we > >> do here. > > > >We have them on residential streets. ;^) > > > >> > >> Which reminds me... why do Americans seem to want such big engined > >> over-powered cars when most of them fall off the road so easily if > >> you use it ? Is it just a macho thing ? > > > Some of us own cars that can negotiate freeway ramps posted as 45MPH > at double that speed with nary a tire squeal ;-) Still doesn't require 7 or 5.7 litre V8s. Or even a 3 litre V8 come to that. Graham |