> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Tachyon
> Sent: Wednesday, December 20, 2006 11:56 PM
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE]:: Bimota centre hub steering
> 
> haha, someone at the EPA needs a new proofreader.
> I couldn't figure what was going on  'till I re-read the 
> actual test spec document.
> The spreadsheets you pointed to didn't jive with the numbers 
> in them which match other data using ppm and other static units.

Hi Tachyon, it's grams per mile.  It's how the cars are rated by the
manufacturer, with the car on a treadmill that varies the load to
simulate both city and highway driving.  It's called the federal test
procedure and I would think that google would return you a whole
evenings worth of reading material about it.

> 
> It's supposed to be grams per MOLE. I bet some secretary 
> thought they were correcting an error and changed it to mile.
> 
> There are two major units used in these tests and a few minor 
> ones. The major two are parts per million (ppm) and grams per 
> mole g/mol.
> 
> If you live in a state that does emissions testing, then 
> you've seen that the cars don't go anywhere. There's no 
> motion or chassis dyno to derive a per distance unit.

Texas does emissions testing, although my particular county doesn't, and
I can assure you that in some parts of the state pre OBD2 cars (1995 and
older) are put on a treadmill.  Denver I believe puts all cars on the
dyno, they found that most of the cars that failed the OBD2 (computer
only) test were in fact perfectly clean.

--steve


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