On Thu, Sep 04, 2003 at 11:04:02PM -0700, Paul Johnson wrote: > On Thu, Sep 04, 2003 at 01:59:03PM +0100, Pigeon wrote: > > Fascinating. How do they compare on raw bhp and power-to-weight ratio? > > The diesel-electrics and fuel-cell busses are taller by about a foot > and a half due to a very large unit on the roof, but it doesn't seem > to be an issue since they still come in shorter than most semi's. What's in that unit - power control gear? Have they gone for a modular design, where you can have a diesel genset module or a fuel cell module and the rest is more or less the same? > > What kind of generator and motor technology are they using to get the > > weight down? Do they have a bank of auxiliary batteries for > > regenerative braking and starting boost? > > They don't do regenerative braking and the engine's always running, > just remains idle or nearly idle except when accelerating hard, and > then it's still not running anywhere near as hard as the > diesel-hydraulics. Well, it does sound like they have much bigger engines than what they replace. > > Fuel cells? Already? Cool. I want one for my bicycle. > > No, you don't. Mopeds aren't allowed to run on power in bicycle > lanes, and tend to go slower than anybody commuting for more than two > weeks can maintain comfortably on their own when on power. Mopeds > weigh a good two to three times as much as a normal bicycle as well; > they're mostly worthless machines. Which is why you don't see many of > them except at car lots that sell electric mopeds to look > environmentally friendly (never mind most of them still have models > five years old unsold on the showroom floor). In the UK, an electrically powered bicycle counts as a bicycle, not a moped (ie. no road tax, no insurance, no helmet etc) as long as it has (a) powered top speed <=15mph (b) max power <=200W (c) max weight <=40kg. 15mph is OK for a bicycle, but 40kg means you get really crap range with a lead-acid battery; a fuel cell sounds great, as long as it runs on methanol or some other convenient fuel rather than hydrogen. The biggest problem is that the max power of 200W is totally useless in hilly areas. To get a 40kg bike + rider + luggage up a 1 in 4 gradient fast enough to maintain balance requires about a horsepower. -- Pigeon Be kind to pigeons Get my GPG key here: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x21C61F7F
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