by cwerdna (Posted Sun, 21 Apr 2013 02:07:46 GMT)
^^^
Re: the EPA tests, viewtopic.php?f=4&t=2433 might help along w/the links from http://priuschat.com/threads/car-and-dr ... tes.67235/.
The C&D article was written WAY before the Leaf and is more applicable to ICEVs. On ICEVs, they derive the fuel economy by measuring tailpipe emissions (not actual fuel consumption) after running a bunch of test cycles (details in the links) while on a dyno. On a BEV, you obviously can't measure tailpipe emissions.
I'm sure there are other threads here on MNL relating to EPA testing on the '11 and '12 Leaf.
Side note: The observation at http://green.autoblog.com/2013/01/03/fu ... -mistaken/ is disturbing.
From that, I and others on Priuschat are wondering if it's Ford optimizing well for the EPA test or if there are intentional or accidental errors in their coast-down numbers as their EPA mileage numbers are real high on recent vehicles (C-Max, '13 Fusion Hybrid, etc.) yet everyone seems to get worse "real world" or similar mileage vs. Toyota hybrids w/lower EPA ratings (e.g. Prius v wagon and Camry Hybrid).
More on the Ford uproar at viewtopic.php?p=248506#p248506 and later there I have links to some info about the Hyundai/Kia screwup.
^^^
Re: the EPA tests, viewtopic.php?f=4&t=2433 might help along w/the links from http://priuschat.com/threads/car-and-dr ... tes.67235/.
The C&D article was written WAY before the Leaf and is more applicable to ICEVs. On ICEVs, they derive the fuel economy by measuring tailpipe emissions (not actual fuel consumption) after running a bunch of test cycles (details in the links) while on a dyno. On a BEV, you obviously can't measure tailpipe emissions.
I'm sure there are other threads here on MNL relating to EPA testing on the '11 and '12 Leaf.
Side note: The observation at http://green.autoblog.com/2013/01/03/fu ... -mistaken/ is disturbing.
Quote:
Through complex calculations, this data then determines a vehicle's road-load energy usage as a function of speed, which becomes a major mathematical factor in the EPA's highway test calculation. So if its reported road-load curve is inaccurately low, a car's EPA highway rating (and also, as a result, its city/highway "combined" rating) will be unrealistically high. And while the EPA audits automakers' test procedures and runs emissions/fuel-economy tests (on a small percentage of vehicles) in its own Ann Arbor, MI dynamometer lab to validate their results, with no suitable facility to run their own coast-down tests, they have had to accept automakers' road-load power numbers as submitted.
From that, I and others on Priuschat are wondering if it's Ford optimizing well for the EPA test or if there are intentional or accidental errors in their coast-down numbers as their EPA mileage numbers are real high on recent vehicles (C-Max, '13 Fusion Hybrid, etc.) yet everyone seems to get worse "real world" or similar mileage vs. Toyota hybrids w/lower EPA ratings (e.g. Prius v wagon and Camry Hybrid).
More on the Ford uproar at viewtopic.php?p=248506#p248506 and later there I have links to some info about the Hyundai/Kia screwup.