I was just reading the IRS Certification for the Altima hybrid and it astonishingly lists 46.8 MPG city on page 2, Item "E", subsection "D"......is this some fuzzy math or am I missing something, I haven't seen any one get that much mileage city. "Model year 2009 Altima Hybrid city fuel economy as determined under 40 CFR s/s 600.002-85(11)"

I would assume Nisan would have to prove they actually were able to achieve that mileage.....?

http://www.nissanusa.com/pdf/altimah...9ALTHybrid.pdf

I tried looking up more information on this but it's very confusing.

 

Interesting, I never looked at the .PDF you referenced before but you've stumbled across some not so well known facts about the stupid EPA mileage tests. Go to http://www.fueleconomy.gov/feg/download.shtml and download the 2009 datafile and unzip it. You will see the exact same 46.8 mpg figure under UNRND CITY (EPA).

http://www.fueleconomy.gov/feg/how_tested.shtml and http://www.fueleconomy.gov/feg/fe_test_schedules.shtml goes over the basic procedure for the old EPA tests which is still used to determine the numbers for CAFE (Corporate Average Fuel Economy) purposes. For model years before 2008, ONLY the city and highway numbers portions were used to determine the numbers that went on the window sticker after being fudged downwards (city down by 10% and highway by 22%, see http://www.epa.gov/fueleconomy/420f04053.htm).

If you lookup a 2007 Altima hybrid at http://www.fueleconomy.gov/feg/sbs.htm and look "Official EPA Window Sticker MPG" (this is before the addition of the extra harsher tests), you'll see 42 city/36 highway.

46.8 * .9 = 42.12
46.6 * .78 = 36.348

In short, if you follow the EPA test procedure (temperature, humidity, etc.) and schedule (be at the right speed at each point in time), drive on a dyno instead of a real road, and measure tailpipe emissions instead of fuel consumed, you should be able to get the above figures.

Even though the window sticker for MY 2008+ now reflects harsher tests, the combined CAFE (UNRND COMP (EPA)) is what used to count toward's a manufacturer's CAFE numbers. There are 3 fleets for light vehicles: import passenger cars, domestic passenger cars, and "light trucks" (SUVs, minivans, pickups and some vans).

old info at http://www.nhtsa.dot.gov/CARS/rules/CAFE/overview.htm
newer/more info at http://www.nhtsa.dot.gov/portal/site...7529cdba046a0/

When the new "35.5 mpg" average standard was being thrown around in the news recently, that's based on this stupid uncorrected EPA dyno numbers of which the NAH already gets "46.7 mpg" and my Prius gets "65.8 mpg". The IP and DP fleets have to already meet "27.5 mpg" else the car maker faces fines. http://blogs.edmunds.com/strategies/...you-think.html is one of many articles on this.

 

Wow, thanks for that detailed reply. It certainly is confusing.

 

Yes, when I bought my 07 NAH the window sticker read 42MPG city. I have achieved those numbers, but is is not possible for me to only drive city, and I cannot get that in the winter.

 

Why is your Real Time average showing 42.8 then?

 

Yes, the window sticker rated 42 city and I am at 42.8. I have achieved 46 on a few tanks and 39 on some highway tanks. Sounds about right, No?

 

I've owned my 2009 NAH less than 24 hours, but this morning on my way to work the computer reported 47MPG. 25 minutes of driving mostly under 40MPH. I tried to maximize EV mode.

 

It definitely can be done at the right conditions. As The Spoils says, it's much worse in colder winters, though. I even have a block heater and a full grill block, but was down in the mid-30s most of the winter here in Rochester, NY.

 

As promised, here is some preliminary FE data for the Prius. I know is is not the right forum, but I feel we are all friends here. Although the MPG is impressive and the car is new, the ride quality and interior is not up to par with the NAH. I'm just glad I did not have to sacrifice one for the other.
Check out the web photo evidence here : http://www.thespoils.8m.com/photo2_4.html

 

You made mention of the NAH so sounds like the right forum to me,