-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Chris Burck wrote: | josh, this is like claiming the engine uses less fuel when it's shut | than when it's running. aerodymics aren't magic. a vehicle moving at | 65mph is still encountering more air resistance than when moving at | 55mph. there are many interesting aspects in automobile technology | today, yet today's average vehicle consumes more fuel than in years | past. it *may* be that today's vehicles are as aerodynamically | efficient at 65mph as earlier vehicles were at 55mph, but that seems | doubtful and in itself means little. gearing? a vehicle in 6th gear | (wish they'd started making them decades ago) will always consume less | fuel at 55mph than at 65mph. can you provide any citations to back up | these rather outlandish claims you make?
Well, One of the most aerodynamic vehicles I've ever had the pleasure to drive is the 3rd (current) generation Toyota Prius. While I haven't logged a lot of miles in one, I've logged a few, and what I've found, is what one might expect. Driving like the more radical drivers suggest works. With the Prius's monitoring, you get really quick feedback on what the vehicle is doing. At highway speeds, momentum works. On one relatively short trip on limited access eastern highways and freeways, I managed to squeak 56 mpg average over 110 miles. Speed? anywhere from 32 to 88 mph. Gently accelerating on downgrades, using the internal combustion engine as little as possible, doing one's best to make the best use of the terrain, and paying no attention to speed 'limits' whatsoever, and letting the momentum gained from battery driven down grade acceleration, remarkable efficiency is possible. Average velocity for the trip? 54mph. 'Pulse and glide' on the flats, decelerating on the climbs, using gravity + some electrical power on the descents. While the Prius, as we all know, has that nifty ability to store energy in an battery bank, the overall concept still applies. This is how the old road tractor pilots used to drive. No regard for 'speed limits', and maximizing every advantage possible. Remember those miles long truck convoys of the 70s? Sometimes moving at incredible speeds? Those guys are paying attention to a lot of feedback that automobile drivers don't. They have exhaust temp monitoring, they have manifold pressure monitoring, they actually know where their torque bands on their power plants lie, most of them were gear heads, and grew up driving farm farm tractors from like age 12 or earlier. Good feel for machinery. Lorry drivers in Europe didn't operate like that, it's unsafe. Unsafe in a relative sense. But there used to be real good money in hauling freight in the US, and quite literally, a gallon saved was money earned. Folks like to point at a lot of statistics on fuel consumption in the US. Couple of things that I keep in mind, in the '70s', folks like to think that cars got better mileage. Well, wouldn't that depend on the car? My father was a big fan of VW beetles. He loved the things, bought his first new one in 62, and owned countless ones over the years, he finally got a diesel dasher, 3rd hand in 81 or so, and drove that thing for another few hundred thousand miles, averaging well over 50mpg the whole way, he could tease a few less drops per mile better than anyone I knew, and drove like there were eggs between his feet and the pedals, that should never be broken. But facts are, the modern highway is no place for a vw beetle, diesel rabbit, nor dasher. The cars on the road today have antilock brakes, traction control, more airbags than you can count, and are capable of crossing the lanes at full speed, and destroying a rabbit, slaughtering the occupants and walking away with a bruise or two, and the lawyers to make sure it doesn't cost anything. I quit driving rabbits about 5 years ago, I'm a hold out. Bought an old subaru outback wagon. It can take a hit, and I drive in the mid-atlantic a lot. Averaging over 25k a year. I can squeak 30+ mpg out of it, mixed-highway. on the weekends anyway. Folks want throw weight in an accident. and an accident is a given. It's assumed. Way back, decades ago, there was a speculative fiction story in Road & Track called 'A nice morning drive' the plot of which was a fellow with an old fun delicate car, an MGB, going out on early weekend drive in the distant future, where HSVs (high safety vehicles) ruled the road. Like the SUV of today, the HSV of fiction can kill you and get away with it, scott free, without real consequence. It's not a great story, but I liked it at the time, and it's lesson has born the test of time very well. Anyway, before I drift way afield of the topic, the Prius is about as good as it currently gets, and it starts building measurable drag at about 22mph, there is a harmonic drop in the drag somewhere in the low 50s somewhere, but the inverse square law still applies. Driving down the highway, isn't a static thing, it's dynamic and the factors that play into fuel consumption are legion. It's completely possible to get better mileage at 65 than 55, but highly unlikely. And nothing, and I mean nothing is worse, than lock-step, high density traffic spaced out far enough to be buffeted about by the turbulence, but unable to take advantage of the low pressure, blah blah blah, in other words, the over-crowded US highway, here in the east anyway. Basically, the whole model is broken, it doesn't work, and it needs to be done away with. A nationwide 55mph speed limit is a piece of ducttape over a rent in a ocean freighter's hull. It's a gesture, but that's all it is. The 'Interstate' system is a bad idea. an overcrowded interstate system is a idea that's orders of magnitude worse. But that's what we have, and it needs to go away. mornings | | On 4/25/08, Josh Boltrek <[EMAIL PROTECTED]> wrote: |> Very well put Chip. Too many people are overly-anxious to demand laws to |> fix what ought to be dealt with using common sense and/or market/social |> forces. Very often, laws are enacted to affect change for things which are |> changing anyway (say, in response to voter 'demand for action'). This can |> often lead to a backlash, as the results tend to swing too far in the |> desired direction. This is because the legislators are simply implimenting |> what is often happening on its own. Thus, we spend half our time |> legislating what 'ought to be the law,' and the other half trying to figgure |> out how to effectively rein-in the results of those laws. |> |> On the topic of speed limits specifically: Many cars now are actually more |> efficient at 65 MPH than they are at 55 MPH (due to gearing, aerodynamics, |> better tyres, etc). The other thing to consider when thinking about speed |> limits is time savings, and how that can affect accident rates. Many |> studies have shown that accident rates have decreased with the higher speed |> on US highways. This seems to be because drivers do not have to spend |> nearly as much time monitoring the speedometer, and they can relax more- |> simply driving at a speed that is comfortable. This leads to less fatigue, |> and therefore fewer accidents. Cleaning up accidents takes a significant |> amount of time and resources, and building new cars to replace crashed ones |> uses even more. |> |> Therefore, I put forward the idea that leaving the speed limits where they |> are will ultimately use less fuel than reducing the speed limits will. If |> petrol gets expensive enough, people will naturally begin to demand higher |> efficiency from their cars, and drive at the most efficient speed for their |> particular car. The most notable result of the 55 MPH speed limit was not |> actually fuel savings, but rather massive revenue gains for the Highway |> Patrol. |> |> Cheers, |> |> Josh |> |> |> |> ----- Original Message ---- |> From: Chip Mefford <[EMAIL PROTECTED]> |> To: sustainablelorgbiofuel@sustainablelists.org |> Sent: Friday, 25 April, 2008 2:46:30 AM |> Subject: Re: [Biofuel] We Need To Solve The Oil Crisis--Now |> |> Brian Schneider wrote: |>> Hello, |>> Just a comment, why don't we in the US do something else that was |>> done in the 70's oil crisis...drop the speed limit back to 55. |> There were a *lot* of problems with this. I'm not going to |> go into it all, in fact, I'm barely going to scratch the |> surface. But essentially, the nationwide 55mph speed limit |> was about as popular as prohibition, and caused many of |> the same problems. |> |> In interest of full disclosure, |> when ever I hear 'There ought to be a law", |> I duck. |> |> We have plenty of laws. a few orders of magnitude |> too many I'd say. In fact, I'd point to the |> current state of affairs as my primary exhibit |> in the 'laws don't fix anything' presentation. |> |> |> _______________________________________________ |> Biofuel mailing list |> Biofuel@sustainablelists.org |> http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel |> |> Biofuel at Journey to Forever: |> http://journeytoforever.org/biofuel.html |> |> Search the combined Biofuel and Biofuels-biz list archives (70,000 |> messages): |> http://www.mail-archive.com/biofuel@sustainablelists.org/ |> |> |> Get the name you always wanted with the new y7mail email address. |> www.yahoo7.com.au/y7mail |> -------------- next part -------------- |> An HTML attachment was scrubbed... |> URL: /pipermail/attachments/20080425/ad0ead5a/attachment.html |> _______________________________________________ |> Biofuel mailing list |> Biofuel@sustainablelists.org |> http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel |> |> Biofuel at Journey to Forever: |> http://journeytoforever.org/biofuel.html |> |> Search the combined Biofuel and Biofuels-biz list archives (70,000 |> messages): |> http://www.mail-archive.com/biofuel@sustainablelists.org/ |> | | _______________________________________________ | Biofuel mailing list | Biofuel@sustainablelists.org | http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel | | Biofuel at Journey to Forever: | http://journeytoforever.org/biofuel.html | | Search the combined Biofuel and Biofuels-biz list archives (70,000 messages): | http://www.mail-archive.com/biofuel@sustainablelists.org/ - -- Chip Mefford - -------------------- Before Enlightenment; ~ chop wood ~ carry water After Enlightenment; ~ chop wood ~ carry water - --------------------- Public Key http://www.well.com/user/cpm -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFIEd5elwL/NsEHg6sRAp0oAJ4ksXMMwiCSDXICO4hELtHGpISbpACcDo08 YWs7bCddEFRmIscB5695Fzg= =VyuU -----END PGP SIGNATURE----- _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (70,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
