>> >Certainly, no one argues with international automotive test >> >findings that better fuel economy can be had with diesel/electric >> >hybrids than with gasoline/electric hybrid vehicles. >> >> I do most certainly argue with this. I measure mileage by >> miles-per-unit-energy, and on that basis, it is not clear to me if diesel >> gets >> better mileage or not. It looks to me like: "about the same", though it's >>hard to say. >> >> I also think that the Battery Electric Vehicle mileage figures I've seen, >on a >> per-unit-energy-onboard basis, by and large get better mileage than the >gasoline >> or diesel cars I've seen, by a wide margin, and they also get better >mileage >> even than the hybrids. I calculate the RAV4 EV as something like 93 mpg >> gasoline equivalent, though I'd have to review some of the issues there, >such as >> whether the mileage is measured at the meter, or onboard, (since there are >> inefficiencies of charging, in some cases very very high).
>diesels most certainly do get higher mpg, The article stated that diesels get better "fuel economy". If this means that a vehicle gets better "miles per gallon", then the assertion is correct and my dispute with it is not correct. *However*, the use of the term "fuel econonomy", in the present vernacular, has not been sufficiently made clear in my view, and I guess that's what I'm trying to get across. In fact, it is ambiguous not only in that it is somewhat natural to view "fuel" as having a standardized energy content (of course: it does not particularly compared to other fuels) but also because the word "economy" somehow makes it easier to allow us to think that the term "fuel economy" might connote "energy efficiency". Most people, if they show some interest in fuel economy have *no clue* that there is more energy in a gallon of diesel than in a gallon of gasoline. Upon learning this, I have seen some assume, wrongly, compounding the problem, that it is somehow "even better" that one is able to wring more mpg out of a gallon of diesel, when in fact the opposite is true, and it is usually not impressive (though it is a matter of degree). Much of this could be cleared up by measuring not fuel economy but *energy* economy. Many people assume without discussion that "mpg" means energy economy which of course is not an equivalency, something that makes it very hard to compare different fuels. I'm sure the oil companies don't mind *one bit* that it becomes difficult to compare different fuels' energy economy, or that even energy activists accept, without a shred of discussion, that it is ok to standardize energy economy discussions to terms already defined in petroleum inexact terms, .... thus conceding much of the battle to Big Oil before it is even begun. "mpg": foo-ey I say. I think this all needs exact clarification and saying diesel gets "better fuel economy" is wrong because it leaves the matter ambiguous for too many readers whom you and I both know have not enough understanding of the matter to sort out that there might be a very significant difference between "fuel economy" and "energy economy". The author of the article we're discussing probably knew this but thought it might be ok to do some shorthand because everyone else does it. It's not ok, in my view. I have yet to see an article which makes the matter clear, except one or two articles which pointed out that PNGV vehicles which came close to 80 mpg on diesel were sort of cheating (though the matter was often glossed-over.) I have a further question that I've never seen examined or discussed which is this: if diesel has more btu per unit volume or mass than gasoline, then I wonder if it takes more of a barrel of petroleum to make x number of gallons of diesel than it does to make x number of gallons of gasoline. If so, then how much more? It becomes possible that the miles-per-gallon of diesel is *worse* than that of gasoline if we are talking about the gallons of crude used per mile. I reckon it might take some doing to get a hard idea as to the answer to that one. >because diesel has a higher btu >count / gallon. > >btu / mile is similar. Yes, I'll agree with that. You and I know this. Most people, including many many energy activists, would have little idea of what you're talking about. I tried to put this chart together a couple of years ago with some of these ideas in mind. I think the best thing for all would be to standardize mileage discussions to a "neutral" energy unit (MegaJoules, BTU, maybe kWh, Erg? what is an Erg anyway?) but some are less neutral than others. We concede too much, in my opinion, by continuing serious energy discussion on terms defined in Oil, (terms brought to us by the same people who cannot give anyone in the US or perhaps on Earth a straight answer as to the price of a gallon of their wares, but insist on this insulting 9/10 of a cent tacked on to every unit sold). The number of BTU per gallon gasoline and I think also diesel is not at all an exact number, so the terms are arguably not even objective or scientifically clear. You get what you pay for but what the heck are you paying for? Here is the chart. Note that it is only when we deal in standardized terms that it *starts* to become possible to discuss EV's and HEV's, and to compare other fuels and their energy content. Of course at that point the Madding Crowd chimes in with various other conversation-enders, such as the energy losses between power plant and EV, and plenty of other assumptions, but one has to start somewhere to get on with this research: http://www.herecomesmongo.com/ae/comptab.html >> >> >> Biofuels at Journey to Forever >> http://journeytoforever.org/biofuel.html >> Biofuel at WebConX >> http://www.webconx.dns2go.com/2000/biofuel/biofuel.htm >> List messages are archived at the Info-Archive at NNYTech: >> http://archive.nnytech.net/ >> To unsubscribe from this group, send an email to: >> [EMAIL PROTECTED] >> >> >> >> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ >> >> >> > > > >Biofuels at Journey to Forever >http://journeytoforever.org/biofuel.html >Biofuel at WebConX >http://www.webconx.dns2go.com/2000/biofuel/biofuel.htm >List messages are archived at the Info-Archive at NNYTech: >http://archive.nnytech.net/ >To unsubscribe from this group, send an email to: >[EMAIL PROTECTED] > > > >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > ------------------------ Yahoo! Groups Sponsor ---------------------~--> Plan to Sell a Home? http://us.click.yahoo.com/J2SnNA/y.lEAA/MVfIAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
