Real world MPG not even close to Ford's Hybrid EPA MPG claims

[gone-ot]

The "EPA testing" process begins with the manufacturer: (A) doing "coast down" tests to find a "road load hp (RLHP)" number for the vehicle. Then, they (B) come up with a supposedly equivalent "test load hp (TLHP)" for the dynomometer they used. So, errors in A propagate into B and so on...

The two equations:

RLHP = (A + BV + CV^2)/7.5 ...A,B,C coefficients for "road"

...where:

V = mph
A = lbf
B = lbf/mph
V = lbf/mph^2

TLHP =(A + 50B + 2500C)/7.5 ...F0, F1, F2 coefficients for "test" dyno

_V = 50 mph
F0 = 36.62 (rolling force)
F1 = 0.1461 (rotational force)
F2 = 0.01869 (aero force)

...example from GM data submitted to EPA:

TLHP = (36.62 + 50(0.1461) + 2500(0.01869))/7.5 = 12.1 "test" hp @ 50 mph

[justme1969]

I posted it somewhere here recently that when I worked at Ford they were just trying out the hybrid regen systems on Escape vehicles. Had massive probblems suddenly in Sept throughout the whole line, it was directly attributed to winter blend petroleum.
Search and learn because it is like a whole different grade of fuel.
Also all fuel has a little bit different recipe if you will allow me that description. so every tank of fuel can be different.

[YeahPete]

I think Ford botched thier numbers. I read the articles. The MPG is off by 10 in this car while most others tested are off by 1-2.

The guy on our forums is hypermiling but is only yielding a 9% Above EPA mileage. Then he drives as a normal person would and yields below EPA.

The EPA is driving under normal conditions, not HYPERMILING. So if your hypermiling you should exceed the EPA claims by at least 20%.

Ex 1: I drove a prius on 2 occasions. I drove for 15 minutes and hit 6 red lights, and a few stopsigns (not hypermiling). Still netted 55 mpg. Then I hypermiled it to pick up a pizza (hypermiled). Netted 75mpg. Above EPA both times. Looks like toyota is conservative in thier estimates.

Ex 2: Last few tanks im averaging 45 mpg in my cavalier, EPA is 23/27/33. Does that mean Chevy can claim 45mpg combined, just because its obtainable by hypermiling?

[gone-ot]

...ALL EPA engine tests are mandated to be done using special 91 octane INDOLENE gasoline which has almost no sulphur content.

...so, not only is there no alcohol dilution, it's a mid-grade fuel, not standard 87 octane, low-grade fuel.

[PaleMelanesian]

Source? I'm not surprised, but I'd like to have something to quote in the future.

[mort]

Originally Posted by Old Tele man

...ALL EPA engine tests are mandated to be done using special 91 octane INDOLENE gasoline, with almost no sulphur content.

...so, not only is there no alcohol dilution, it's a mid-grade fuel, not standard 87 octane, low-grade fuel.

Except the car company can recommend higher octane. For Federal certification, the minimum octane by research number is 93 and the motor number not below 85.5, so the minimum R+M/2 is 89. For 50 states certification based on CARB reformulated gasoline - the minimum R+M/2 is 91, except for this note

ii) Unless otherwise approved by the Administrator, the octane rating of the gasoline used must be no higher than 1.0 Retail octane number above the lowest octane rating that meets the fuel grade the manufacturer will recommend to the ultimate purchaser for the relevant production vehicles. If the manufacturer recommends a Retail octane number rather than a fuel grade, then the octane rating of the service accumulation gasoline can be no higher than 1.0 Retail octane number above the recommended Retail octane number. The service accumulation gasoline must also have a minimum sensitivity of 7.5 octane numbers, where sensitivity is defined as the Research octane number minus the Motor octane number.

If the manufacturer recommends "regular grade" then the test can be done with 87 octane, but mostly the manufacturer can require premium and then use 93.
-mort

[gone-ot]

Originally Posted by PaleMelanesian

Source? I'm not surprised, but I'd like to have something to quote in the future.

...ask and ye shall receive:

WHEREAS, a federal gasoline test fuel, specified in title 40 CFR Part 86, subpart B, section 86.113-94(a)(1), is known as "Indolene";

...that's from this CARB document:

http://www.arb.ca.gov/regact/2011/so...ore15app15.pdf

...and, here's the Federal document that's referenced:

eCFR — Code of Federal Regulations

...notice the name "indolene" is NOT specifically called out, but if you chase the listed specifications, indolene is the ONLY fuel that meets the requirements. It is 100%-government-speak in print: they simply state the indolene specifications without using the indolene name.

[niky]

Originally Posted by euromodder

As the test procedures are laid out, all companies engineer their vehicles to pass the mandated tests as good as they can.

When real-life driving conditions don't sort of match the test conditions, you can get severe discrepancies.

While many can match EPA numbers, most people here in Europe won't match their car's NEDC numbers.
That's not because they drive with even less concern that the Yanks or idle even more - quite on the contrary, with $8 gas and diesel ... - it's simply because the NEDC test is a far cry from reality.

Seeing as how in recent technical articles I've read, some supercar and sports car makers have bragged about acing the urban part of the NEDC simply by making the battery of their hybrids just big enough.

-

The EPA may be flawed, but the current EPA drive cycle is easy to beat. The problem now being, how easy it is to beat varies widely, making it an uneven measuring stick.

[bwilson4web]

Hi,

Originally Posted by Old Tele man

The "EPA testing" process begins with the manufacturer: (A) doing "coast down" tests to find a "road load hp (RLHP)" number for the vehicle. Then, they (B) come up with a supposedly equivalent "test load hp (TLHP)" for the dynomometer they used. So, errors in A propagate into B and so on...

The two equations:

RLHP = (A + BV + CV^2)/7.5 ...A,B,C coefficients for "road"

...where:

V = mph
A = lbf
B = lbf/mph
V = lbf/mph^2

TLHP =(A + 50B + 2500C)/7.5 ...F0, F1, F2 coefficients for "test" dyno

_V = 50 mph
F0 = 36.62 (rolling force)
F1 = 0.1461 (rotational force)
F2 = 0.01869 (aero force)

...example from GM data submitted to EPA:

TLHP = (36.62 + 50(0.1461) + 2500(0.01869))/7.5 = 12.1 "test" hp @ 50 mph

I remember stumbling across the EPA page that had many of these values for different model cars. Do you have a URL handy or is it in the public domain?

THANK YOU! Found it:
http://www.epa.gov/otaq/tcldata.htm

Having the coefficients makes it possible to compare vehicle, not engine, performance so we can gain a clue.

Thanks,
Bob Wilson

[radioranger]

you're forgetting one big thing which is incredibly fit into the mold, Obama wants Ford to look bad, The media will NEVER want ford to look good . they bucked the bail out, you have to ,very sadly to say , look at darned near everything that way now, If it's not in the agenda it's not good for the Elite, it's downplayed by the media,