Yes, Stan, J/km first, and then $/km. ---- Original message ---- >Date: Thu, 10 Jul 2008 12:12:42 -0400 >From: "STANLEY DOORE" <[EMAIL PROTECTED]> >Subject: [USMA:41384] Re: FW: Impressions of a Futurecar - FlowChart >(usnews.com) >To: "U.S. Metric Association" <[email protected]> > > Hydrogen, batteries, gasoline, diesel, > biofuel, etc. How to compare the energy and > efficiency of these? > Why not J/km (Joules per kilometer) as the > common unit of SI measurement? Cost per kilometer > is really what we want to know for economic purposes > isn't it? > Stan Doore > . > > > > ----- Original Message ----- > From: Nat Hager III > To: U.S. Metric Association > Sent: Thursday, July 10, 2008 4:34 AM > Subject: [USMA:41377] FW: Impressions of a > Futurecar - FlowChart (usnews.com) > > Sorry, missed the most controversial part…. > > Hydrogen car article in US News….. > > >>>Kilograms per what? The Hydrogen 7 has one of > those onboard computers that display your fuel > efficiency—for both gasoline and hydrogen. Gas > mileage, of course, is measured in the familiar > mpg. But hydrogen mileage is flipped around and > expressed in kilograms per 100 kilometers. This > took a bit of noodling to understand, like > figuring out the inverse of a currency exchange in > a foreign country. Simply put, it's the metric > version of how many gallons it takes to go 100 > miles. If you're averaging 4 gallons per 100 > miles, for instance, that's the same as 25 miles > per gallon; 3 gallons per 100 miles would be 33 > mpg. So in hydrogen terms, the lower the number, > the better. > > I started out averaging 3.3 kilograms of hydrogen > per 100 kilometers. I tried to drive gently and > see if I could improve on that, and I got it down > to 2.9 for a while. Then I hit traffic, and it > went back up to 3.2. I studied the instant > efficiency reading, too, which ranged from 0 to > 10. When coasting at about 50 miles per hour—a > very efficient speed for most cars—my hydrogen > consumption was less than 2 kilograms. But when > pressing hard on the accelerator to pass somebody, > I pegged the meter, burning the maximum 10 > kilograms (or more). > > If hydrogen catches on, there will have to be > standardized metrics for expressing fuel economy. > My guess is that the federal government will adopt > something similar to the mpg construct, while > taking account of the fact that hydrogen is > typically measured by weight, not volume. So an > Americanized version might be expressed as miles > per pound. If that were the case, my 3.3 kilograms > per 100 kilometers would equate to about 8.5 miles > per pound of hydrogen. I think. Or maybe we'll > just have to join the rest of the world and learn > the metric system. > > >>> > > > http://www.usnews.com/blogs/flowchart/2008/7/9/impressions-of-a-futurecar.html > > Nat
