FORD revises MPG for 6 cars

I don't know where you're getting your numbers from, but Greenercars.org has done this well-to-wheel analysis already. They don't show that EVs are dirtier than gasoline (with the sole exception of the Tesla).

Yes when the PiP (or Volt or plugin Fusion) runs off the energy of the grid, it is more efficient than when making energy locally (burning gasoline). It isn't a huge difference, a few percent, but it is there.BTW
Ford dropping the Cmax all the way from 47 to 37 highway makes them look incompetent. They don't even know how to run a simplest test in the EPA fuel economy range. Plus to quote an article: "Embarrassingly for Ford, the Fiesta’s downgrade now makes the 2014 Mitsubishi Mirage tops among non-hybrids," which negates all of Ford's braggard ads.

EPA tells Ford to fix fuel-economy data now, gives auto maker 15 days to make it happen : FUTURE TECH : Tech Times

 

BTW
Ford dropping the Cmax all the way from 47 to 37 highway makes them look incompetent. They don't even know how to run a simplest test in the EPA fuel economy range. Plus to quote an article: "Embarrassingly for Ford, the Fiesta’s downgrade now makes the 2014 Mitsubishi Mirage tops among non-hybrids," which negates all of Ford's braggard ads.

EPA tells Ford to fix fuel-economy data now, gives auto maker 15 days to make it happen : FUTURE TECH : Tech Times

 

Didn't miss it. At that time, it was revealed that they used the fusion numbers for the c-max, which used a loophole in the regulatoins. This time they used the wrong coast down numbers. There definitely seems to be a problem at ford, I hope they have fixed it.

The key number is combined, which on the c-max dropped from 47 to 43 to 40. The highway number really seemed to poke the pooch, as you said it went from 47 to 37 mpg. With that drag number it looked impossible that it got 47 mpg on the highway, when the much more aerodynamic prius only got 48 mpg. The numbers for the fusion still look good at 44/41/42, but I expect we will see backlash in the next couple of months as people choose the non hybrid fusion with 26 mpg combined versus the hybrid fusions 42.
Compare Side-by-Side
I find the 45mpg highway on the accord hybrid highly suspect also. I wonder if that is real.

 

I'm no Fuelly aficionado, but my back of the napkin calc's from their website seem to agree you. The Accord Hybrid runs around 2mpg-3mpg (blended) less than Honda's claims. That's tantamount to what a lead footed genII Prius owner gets.
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No actually the "key" number is the CAFE because that's what will lead companies to losing money if they don't meet it. (And really that's all Ford, Toyota, Honda, etc care about: Money. They don't care about their customers or workers.) So did the CAFE number on Ford's cars drop?

 

I told you where the numbers were from. Here if you are too lazy to google.

Beyond Tailpipe Emissions

 

Yes on this second revision cafe numbers dropped, but not as much as the epa values. The cafe numbers only use the slow highway test, which is not nearly as effected by the roll down numbers, and the very slow city test without air or heat, which will have very high numbers. Hybrids do better on the cafe tests versus the epa new tests.

 

50 MPG gas engine is as clean as 100 MPGe EV (about 220 gram/mile). Volt or Energi electric efficiencies are rated at 98 and 88 MPGe. Their EV miles may be cleaner than their 37 and 38 MPG gas engines. See why balancing the two power sources to get the most out of both is important?

When PiP runs on electricity, it gets 130+ MPGe (thanks to lower speed threshold). Combine that with 50 MPG gas engine, we have a winner. Remember, 95 MPGe rating is a combination of electricity and 0.2 gallon of gas -- still higher than Energi pure EV at 88 MPGe.

There is advantage burning gas locally. Waste heat from the exhaust gets recycled and used to warm up the cabin. That increases EV efficiency because you don't need to run the electric heater.

But then you use gas. Yes, so does a regular Prius rated 50 MPG, so it is nothing new. This approach just increases electric efficiency hence reduces emission.

PiP was artfully crafted from tailpipe and beyond. Ford Energi plugins (and Volt) sacraficed gas efficiency (and electric as well) for the sake of bigger battery. Government actually promote it as the incentive is tied to the capacity of the battery. Toyota was the only manufacturer that went with sicence and stayed true to Prius objectives (Project G21).

 

I agree on the "equally as clean" part (given the US mix of coal, CNG, etc), but I wasn't discussing that. I was discussing efficiency.

Which is a detriment in the summer. Then the car is making heat for no good purpose, whereas an electrical powerplant can recycle that heat to spin a few power turbines. More efficient. (And by the way: Even in winter the car makes more heat than you need..... unless you enjoy 150 degree passenger areas. )

Oh okay..... well I prefer the manufacturing-to-recycled numbers (or well-to-wheel numbers) when looking at such things. Looking at the tailpipe alone is not enough, especially for cars that don't have tailpipes.

 

In the summer, A/C runs on electricity, so gas engine wouldn't start.

Even if it runs due to higher speed or for more power, it would propel the wheels. It wouldn't stop using the battery either as both power can be blended.

Engine warm up takes about 2.5 ounce of gas. That amount is very little compare to those interstate vacation freedom drives. That's where the 50 MPG engine saves a lot of gas. ICE assisting in EV mode increases EV efficiency. Those are very good reasons.

There are power plants with combined cycle as you described. Despite that, the grid efficiency is about 33%.

Life cycle analyst is exactly that.

Toyota was against big batterybpack due to carbon footprint in manufacturing Lithium battery pack. So, they designed PiP to get the most out of 4.4 kWh pack.

 

So I took the EPA test car data and compared the measured, roll-down coefficients, and the dynamometer set-coefficients to find which vehicles had the greatest differences. Most were low mileage, low volume cars like the Jaguar XJ and Maserati Quattroporte which would not have large sample sets in Fuelly.com. But one surprise was the Golf diesel:

• 501% offset
  • -265% @35 mph
  • -425% @70 mph
• 34 MPG combined EPA
  • 30 MPG city
  • 42 MPG highway
• 40 MPG highest bucket FUELLY
  • 34 MPG 6th low bucket from highest FUELLY
  • 46 MPG 6th high bucket from highest FUELLY

So my first pass indicates the Golf diesel is badly 'sandbagged.' Its field and measured performance is significantly better than the EPA sticker numbers. If the pattern holds true then vehicles with positive, offsets are likely to be 'optimistic' in their EPA versus field performance.

BORING TECHNICAL DETAILS

1. Start with the 2014 EPA Test Car CSV file (downloadable)
2. Calculate the HP required at:
   1. 35 mph using roll-down
   2. 70 mph using roll-down
   3. 35 mph using set dynamometer
   4. 70 mph using set dynamometer
3. Calculate the % change between the roll-down and set coefficients, preserve sign
   1. low speed offset %
   2. high speed offset %
4. Calculate the root mean square of the two offsets

I sorted the list to identify the ones with the greatest RMS offset and by inspection, found the Golf. The worst was the Nissan Titan 4WD Crew cab but this model has a small sample set in Fuelly and the small digit, integer, EPA numbers makes it difficult to detect any differences.

Bob Wilson

 

Is there a stand out gasoline model?
The EPA test, or possibly the entire procedure, generally underestimates diesels to begin with.

 

You'll probably find the same with the Jetta and Passat diesel, Bob. Actually most diesels in general, the EPA test seems to underestimate their real world performance.

 

I was interested in finding similar errors to what Ford found. Although I could probably reconstruct the EPA numbers, it really wasn't part of what I was searching. For example, I needed the FUELLY numbers to confirm there was a problem, not just the table values which only suggested where to look.

As for diesels, the Golf was found because the table analysis suggested it was a possible candidate. Then when I compared the FUELLY and EPA MPG numbers, it was clear that particular model has a problem. Others may also have similar errors suggesting a methodology problem by this vendor, VW.

The biggest problem has to do with vehicle MPG:

	MPG	max error % / avg error%
1	10 MPG	10% / 5%
2	20 MPG	5% / 2.5%
3	25 MPG	4% / 2%
4	33 MPG	3% / 1.5%
5	50 MPG	1% / 0.5%

What this means is as the vehicle MPG increases, the ability to detect a problem improves as the rounding errors become smaller. But the less efficient ones are masked . . . as if we care.

Bob Wilson

 

Let's rewind: I said, "Yes when the PiP (or Volt or plugin Fusion) runs off the energy of the grid, it is more efficient than when making energy locally (burning gasoline). It isn't a huge difference, a few percent, but it is there"

You replied, "There is advantage burning gas locally. Waste heat from the exhaust gets recycled and used to warm up the cabin."

Then I said it's a "detriment in the summer. Then the car is making heat for no good purpose, whereas an electrical powerplant can recycle that heat to spin a few power turbines." You wrote, "In the summer, A/C runs on electricity, so gas engine wouldn't start."

So we're back to where we began when I said running off the grid is more efficient than running gasoline.

And the EPA doesn't use it. They said their analysis is "based on the vehicle's tailpipe carbon dioxide emissions only".

 

Gas production+transport is 83% efficient. Prius is 39% efficient.

Electricity production+distribution is 33% efficient. EV is 85% efficient.

Which path is more efficient?

Emission is closely related to efficiency. Renewable source does throw monkey wrench but it is a small percentage in current grid mix.

 

The problem with 'can' is that it actually only happens so rarely as to not matter.

So the reality is that waste heat is wasted year round in the EV while it is wasted only in the non-heating season in the hybrid or ICE car.

That is the waste heat. If you consider other elements of the fossil_fuel-to-wheels analysis, EV falls even further behind:

• Prius averages about 36% thermo efficiency, average grid about 33%
• 17% losses to make petrol from oil, compared to 8% electric transmission losses from plant to home, ~ 15% losses from wall to battery, and 8% losses from battery to wheels

Add it up and you get:
Prius oil to wheels* = 0.83*0.36 = 30%
EV fossil fuel plant to wheels = 0.33*0.92*0.85*0.92 = 23.7%

The above is summer. Winter is worse.
Note that I averaged fossil fuels. NG matches or beats Prius while coal is worse.

*I did not calculate the fraction of Prius ICE output that takes the electrical path. Some 28% of the energy flow incurs an additional 15% loss. A better estimate then is (36*72 + 36*0.85*28)/100 = ~ 34.5 ICE efficiency, and 34.5*0.83 = 28.6% oil to wheels.

 

Volt and Energi gas engines are not as efficient as Prius. So, what TH said maybe true of those plugins but I have not done the math yet.

 

Sage, 33% includes transmission loss already.

 

I don't think so.

For instance, this link from the EPA