FuelEconomy.gov official ratings posted - 58 City/53 Hwy Prius Eco - 54 City / 50 Hwy for Prius

With my old 2013 Prius three and my 2015 persona (both obviously liftbacks) I would shift to neutral on most extended downhills.... I do believe it aided in mpg...

With my v I don't tend to do so as I find it more difficult to P&G as the regen display is diff and is not linear as compared to the liftback. Personally I dislike the display on the v and much prefer the linear regen display on the liftback. So much easier to regulate..

 

If you still want a technical answer, pose the question here: Efficient driving for a 1,000 mile tank | PriusChat

Bob Wilson

 

I didn't read the whole post but you are wrong, under 46 mph engine pistons are not moving, MG1, MG2 and PSD (transaxle) are all spinning, but engine is not moving one bit. There are probably more losses in this kind of simulated "Neutral" than a regular declutched transmission, but difference is definitely not that big.

 

I'm pretty sure that Wayne Gerdes was having them shift to neutral because he had not taught the driver another advanced technique. That technique is holding the accelerator in a position where you're not creating any regen to the battery nor using any battery power. He mentioned several times that the driver would use this other technique very soon.

 

Thats called the Pulse and Glide method (P&G)

 

I referred to it as "the sweet spot."

 

Question- Do we know CAFE MPG assigned to Gen4?
I estimated >80 on a different web site but I wonder if that's true?

Slightly off topic, but also how would an BEV like Nissan Leaf compare on CAFE?

 

Not sure about the Leaf, but Tesla scored 277 in 2014.
I would guess the Leaf would score higher as it is more efficient, but I could only find breakdown by company.
http://www.nhtsa.gov/staticfiles/rulemaking/pdf/cafe/Performance-summary-report-12152014-v2.pdf

 

Source: Test Car List Data Files | Cars and Light Trucks | US EPA

Yes, the Prius ECO made it, 82-84 MPG and meets the PNGV goal.

Bob Wilson

 

That is a ton of data!
I couldn't parse out CAFE values though, unless the mpg are CAFE. They seem too low though.

 

Help us with the data Bob. Seems like only Gen4 2eco is tested. Could that possibly explain why 2eco has 58 MPG? The others simply not tested. Which cycle is CAFE.

 

Source: Fuel Economy | US EPA

My understanding is the 'ftp' test, MPG number is the one used per vehicle: http://www3.epa.gov/fueleconomy/documents/420f14015.pdf

10. Why are CAFE values different than the mpg estimates given on a car’s window sticker?
Will consumers achieve 54.5 mpg with new cars in 2025?

The Corporate Average Fuel Economy (CAFE) program has a different purpose than the EPA/DOT Fuel Economy and Environment Label (or window sticker) and the mpg estimates used for each program differ accordingly. CAFE is the required average fuel economy that individual manufacturers must meet for their fleets of passenger cars and light trucks manufactured for sale in the United States for each model year. The National Highway Traffic Safety Administration (NHTSA), within the Department of Transportation, establishes and enforces the CAFE stan dards, while EPA performs vehicle testing and CAFE calculations.

CAFE values are calculated from the EPA vehicle fuel economy database (based on testing at both EPA and automakers, including the test data used to determine the fuel economy estimates for the labels.) However, the law requires that the methodology used to calculate fuel economy for CAFE compliance be consistent with the 1975 test methods so, unlike the label values, CAFE mpg estimates are not adjusted to reflect real-world driving conditions. As a general rule of thumb, the combined mpg estimate on a vehicle’s window sticker is about 20% lower than its combined mpg estimate for CAFE, though the actual difference depends on the particular vehicle. For consumers, the label value provides the best estimate of the fuel economy they are likely to experience in real world driving.​

Top 1% of the ~2,000 FTP test entries:

	model	FTP test MPG
1	IMPALA	10000
2	Audi A6	10000
3	Audi A6	10000
4	Audi A6	10000
5	Audi A6	10000
6	MIRAI	94.1
7	PRIUS Eco	84.1
8	PRIUS Eco	84.1
9	PRIUS Eco	82.5
10	PRIUS	78.0
11	PRIUS	77.3
12	PRIUS c	75.0
13	PRIUS c	71.4
14	PRIUS	71.1
15	PRIUS c	69.0
16	Tucson Fuel Cell	68.0
17	PRIUS c	65.9
18	PRIUS	64.9
19	PRIUS v	61.5
20	Fusion (HEV)	60.6

I am expecting some 'adjustments' of the Impala and A6 numbers. It looks like GM has borrowed the same German translators that VW/Audi used for the diesel NOx testing.

Where are the Leaf and Tesla numbers?

Bob Wilson

 

Those are not CAFE numbers.
Various adjustments are made to attain the CAFE numbers.
As for the FTP numbers, I am not sure how those are attained. The ones for Tesla (23 - 30mpg) don't even make sense.

 

We need model year for the above table...I am thinking eco is only 2016 Prius model, but not sure.

The 54.5 MPG target is really hard to understand...it's really 40 EPA MPG but then automakers get all kinds of credits, and 54.5 MPG may go down if more F150's lower the average...gets to the point where I think we're really talking 30-35 MPG vs. 25-26 today.

 

Follow the link in post 109
Source: Test Car List Data Files | Cars and Light Trucks | US EPA

 

Technically you are correct. Following the baseline, 1975 testing protocol:

• 55% * FTP ## urban cycle
• 45% * HWFET ## highway cycle

Poor urban performance has been the biggest driver because the highway cycle is so much easier. Being a Prius owner, I simplify the calculations by using just the FTP MPG. Regardless, the raw data is available in the source file and can be easily enough calculated:

1. Extract the FTP cycle MPG for each model into a table, keep the best
2. Extract the HWFET cycle MPG for each model into a table, keep the best
3. Combine the two and use 55% and 45%

Bob Wilson

 

Thanks Bob.
Shame, I was hoping there was the actual CAFE numbers somewhere in there.

It seems there is a lot more going into the new CAFE ratings. I found some details here, Corporate Average Fuel Economy - Wikipedia, the free encyclopedia

Specifically

This also has some interesting info: The CAFE Numbers Game: Making Sense of the New Fuel-Economy Regulations - Feature - Car and Driver

I'd really like to figure how this is all calculated on a vehicle, not fleet, basis. It is very convoluted though.

 

Careful what you ask for:

	make-model-id	FTP	HWY	CARB MPG
1	CHEVROLET-IMPALA-361EGP4200	10000.0	10000.0	10000.0
2	AUDI-Audi A6-GAAC-CAF	10000.0	10000.0	10000.0
3	AUDI-Audi A6-GAAC-CAQ	10000.0	10000.0	10000.0
4	CHEVROLET-IMPALA-361EGP4200	10000.0	39.3	5517.7
5	TOYOTA-MIRAI-16-JD1F	94.1	94.1	94.1
6	TOYOTA-PRIUS Eco-16-ZV2H	84.1	78.2	81.4
7	TOYOTA-PRIUS Eco-16-ZV2H	84.1	76.9	80.9
8	TOYOTA-PRIUS Eco-16-ZV2H	82.5	78.2	80.6
9	TOYOTA-PRIUS-16-ZV3H	77.3	76.1	76.8
10	TOYOTA-PRIUS-16-ZV1H	78.0	71.2	74.9
11	TOYOTA-PRIUS c-12-NP2H	75.0	71.4	73.4
12	Hyundai-Tucson Fuel Cell-LMFCTV000098	68.0	71.9	69.8
13	TOYOTA-PRIUS c-12-NP1H	71.4	66.6	69.2
14	TOYOTA-PRIUS-16-ZV1H	71.1	66.0	68.8
15	TOYOTA-PRIUS c-12-NP2H	69.0	68.0	68.6
16	TOYOTA-PRIUS Eco-16-ZV2H	56.3	76.9	65.6
17
18	Pagani Automobili-PT4-EDV14PAG01	12.9	20.4	16.3
19	Ferrari-F12 Special Series-180311_F152VS	13.0	20.1	16.2
20	LAMBORGHINI-AVENTADOR-LB83-DSSCD	11.5	21.2	15.9
21	Mercedes-Benz-AMG G65-G463E60TC-Z6021	13.0	18.6	15.5
22	Ford-F150 FFV 4X4-FFA00014	12.8	18.8	15.5
23	TOYOTA-TUNDRA 2WD FFV-16-SK1A	12.0	18.1	14.7
24	TOYOTA-TUNDRA 4WD FFV-12-SK4A	11.9	17.3	14.3
25	TOYOTA-TUNDRA 2WD FFV-16-SK1A	11.5	17.7	14.3
26	TOYOTA-SEQUOIA 4WD FFV-12-SK4A	11.4	17.5	14.1
27	TOYOTA-TUNDRA 4WD FFV-12-SK4A	11.6	17.2	14.1
28	TOYOTA-SEQUOIA 4WD FFV-12-SK4A	11.1	17.2	13.8

Bob Wilson

 

Don't forget EPA test are conducted with 100% pure gasoliine, no Ethanol, unless of course for E-85. So from the start, results will be 3-5 % lower when you use E-10 gasoline.

 

Really? I did not know this..

If true that's kinda screwed as pure gas is next to impossible to find most anywhere that I know of?