Hi Lars-ss:
___You may not be seeing the reality of the EPA’s city and highway tests. The results are what they are in the test(s) that are run even if the test forces a Prius II or Escape HEV into a sustained EV mode. The pack helps the Prius and Escape HEV run quite a bit of the FTP75 in EV but the overall FE and emissions are measured and are what they are because the gasoline ICE is what charges up the pack AND propels the Prius, Escape HEV, Insight, HCH, whatever etc. … If someone were playing the devils advocate, they might say non-hybrids do not have to run their ICE to recharge a pack so the results are flawed in favor of the non-hybrids! This is just as much bunk as the assumptions quoted. If you ran your HCH or a Prius II in the exact manner with the exact setup as that of the (2) EPA tests used for the estimated FE with the city/hwy deduction taken, you would receive very close to what the EPA did with both EV in the case of the Prius and Autostops in the case of the HCH. Any new Toyota Sequoia, Chevrolet Yukon, and Ford Expedition would come very close to their respective EPA estimates if setup per the manufacturers specs and over the same exacting test cycle as well. There is no faking anything. The bag measurement gives the amount of fuel consumed as well as emissions over the particular test cycle including the exact distance, acceleration rates, deceleration rates, as well as at idle/autostop/EV mode while sitting there ICE off during the non-hybrids idle portion of the same test.

___If you wanted to look at a hybrid in the negative per the EPA test cycles, you have heard of a NOx spike upon start of just about any ICE, right? The Hybrid’s have quite a few ICE starts and stops whereas the non-hybrid’s do not. What does that due to a hybrid’s overall NOx emissions? They still meet very clean std.’s including SULEV and LEV for the HCH depending on config, SULEV to LEV for the FEH depending on locale, SULEV for the Prius I and II as well as HH and RXh, SULEV, ULEV, or LEV for the Insight depending on fuel and config, and ULEV for the AH. They maintain their standing in the FTP75 and HWFET tests even though they had all of those opportunities for a higher NOx output with a NOx spike on every re-ignition. The CAT’s are warmed up to help of course but there is still a NOx spike no matter how small after a given period of ICE off.

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Lars,

Only two conditions matter: the distance driven, and the energy used. The Prius could *FLY* during part of the EPA, for all it matters. The data would not be false.

I think you are arguing that the Prius is OPTIMIZED for the EPA route; and that the EPA test is a poor model for (your?) driving experience. That indeed may be true -- for you. My experience suggests otherwise. I accelerate modestly, time red lights, tend to drive below 40 mph on city streets, and glide when I can. What you seem to be calling other-worldly conditions, I call safe and reasonable city driving.

 

OK guys, y'all are ganging up on me here, and I seem to have failed to make my point. I'll say this one more thing, and if you don't get it, then I'll just drop it.

If a consumer's normal commute is average 20 mph, with 23 stops, 11 miles in 31 minutes, with a max speed of 56 mph, then THAT is the EPA test run. That person should get 60 MPH "WITHOUT USING ANY HYPERMILER TRICKS AT ALL*, no overinflated tires, no coasting, no pulse driving, nothing special.

I'm saying that is not probable and not likely and is not a reality. That makes the EPA test a farce for the Hybrid, and overstates the MPG by a large margin.

I do not think that even one of the drivers at GH.COM could get 60 MPG in a Prius in their normal commute "without using any hypermiler tricks". To do so would mean their commute is even simpler than the EPA test run.

Thus, because of the flawed nature of the test, any car which runs MORE IN EV MODE THAN A NORMAL DRIVER might experience, then the test is logically skewed more in the benefit of the hybrid.

This is the ONE REASON why we have people who complain about not getting 60 MPG in their City commute....

 

You seem to want the EPA to change it's city cycle to "Larry's drive to work." I'm afraid you are going to stay disgruntled.

At it's best, a test cycle gives a level playing field, to COMPARE one car to another. The presumption is that if the Prius gives 20% better mpg than the HCH in the EPA test, the same 20% difference would occur in your hands. It does NOT mean you will get 60 mpg. See the difference ?

You might argue that the 20% difference will only occur in a specified set of conditions that most drivers will not experience. That is a different argument, and one you have not argued persuasively.

A separate question is how far removed is the EPA cycle from real-world conditions. As I have said before, almost all my driving is in the city, and I have no problem at all hitting over 60 mpg, and usually closer to 65 mpg.

ymmv, as does mine, but hitting EPA does not take a Dan K or Wayne. It does take anticipatory driving, at least for me. Is that what you have against the EPA cycle ?

None of the above has squat to do with EV.

 

No, I don't want the EPA to change anything for ME personally, but even THEY know they need to change their testing, and they are looking into that.

All I have "against" the EPA cycle is what reality shows us - it is Flawed and needs to be revised toward realities of today's driving styles and habits.

As the test stands right now, today, the Prius is rated "too high" for reality, and thus leads to shattered expectations, and leads people to "badmouth" Hybrids, which I do not like to read or hear. It's not the TECHNOLOGY'S fault, it's the EPA tests which are raising expectations too high.

That's nothing new, and is not only my personal opinion but is also common knowledge in the automotive world. I can post links if you like.....

 

Certainly, many people in the vast majority of cars end up with mpg less than the EPA mean. The AAA used to have a long list of cars that they tested that shows this rather clearly. It also shows just as clearly that the Prius is not better or worse than than the average non-hybrid -- around 10% less than EPA.

Demands to decrease the hybrid EPA results unilateraly are unfounded and without merit. A more demanding EPA test cycle is an interesting question, but it is NEVER going to happen. Detroit barely makes CAFE as it is.

 

I think the test is flawed, in that the Prius gets much higher results than they should rate it at, meaning the Prius is optimized for the test conditions, and those conditions are closer to Japan real world conditions. I do think that if you repeated the same test in the real world, in a fully broken-in Prius you will get the same result as the EPA. The car is capable of this kind of efficiency when driven with FE in mind, and part of the design of the car is to show current fuel consumption in order to keep FE in your mind. The problem in my opinion is that they are giving you an MPG rating for a specific, small trip, either on the highway or in the city, not what you'll get per tanks, or per day, but what you'll use in a specific "test" and that in itself is not a good way to represent the fuel efficiency of a car. Average consumption is a WAY different number, and that's not what the tests are claiming to be, but most people assume they are. I find the numbers at GH more informative, and probably the same kind of thinking lead to the creating of this place.

But I think it's most important to be able to see the RANGES up front, since it shows the possibility of the vehicle. The fact that it can perform bad when driven bad may be important to people, like taxi drivers or other mainiacs on the road. For others it's important to see how good it can perform so they can work to improve their fuel economy.

 

Here is a story which says basically what I was trying to say in a more concise way than my efforts:

http://www.autosafety.org/article.php?scid=77&did=854

 

Check out the Japanese city drive cycle for something *really* divorced from reality. Prius gets around 80 mpg if I remember correctly

I wonder how the Japanese public deal with the posted numbers when they go to buy a fuel-sipper. Perhaps they just compare vehicles one to another, and realize the car they end up buying will get around 60% of stated

 

Quoting D. Hermance from the article lars-ss posted:
"It really is 50th-percentile driving. No one drives like that anymore."

So if people did not speed to a red light, the test cycle would be OK ??

I'm going a bit off-topic, but why legitimize lousy driving habits ? That the majority drive that way seems a **** poor excuse. I can't help but see this as another example of the US propensity to modify a test to the least common denominator, so that everyone feels good about themselves.

"No Driver Left Behind"