Ford Hybrids' Fuel Economy Failing To Live Up To EPA Ratings?

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by jsfabb, Nov 20, 2012.

  1. SageBrush

    SageBrush Senior Member

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  2. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Motor Trend's Car of the Year issue reported they got 37 on the C-Max.
     
  3. Trollbait

    Trollbait It's a D&D thing

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    Oh yeah, it has little affect on highway.
    Your statement about car weight and braking was seperated from the highway paragraph. So I thought it applied to both highway and city.
    Car weight has little effect if the friction brakes are not being used.
    edit: that was messy. Didn't see the pastes in the message field before repling.

    CR's reported 32mpg city for the Prius wasn't an instant reading.
     
  4. SageBrush

    SageBrush Senior Member

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    I'll try one last time to be clear (although I think I have already):Low highway fuel economy results reported by C-max owners compared to Prius at similar speeds cannot be entirely (or even mostly) explained away by the C-max's heavier weight.

    1-2* mpg difference from weight -- yes.
    The remainder -- other causes.

    * -- 1 mpg if the weight difference is 10%, 2 mpg if the weight difference is 20%.
     
  5. walter Lee

    walter Lee Hypermiling Padawan

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    Whether a vehicle is overweight or not depends on how efficiently and how fast its power plant can deliever power(power curve) for its given curb weight. The Prius powerplant uses a more fuel efficient Atkinson Cycle gas engine which has slower power curve/response. The Atkinson cycle engine is almost as fuel efficient as a diesel engine (which says alot). On the other hand, the Corolla uses a less fuel efficient Otto Cycle gas engine but it gets a faster power curve/response for this trade off. While both the Corolla and the Camry can get better FE if they accelerate more slowly - the Prius benefits even more so by accelerating more gently - this is difficult to observe unless you have a Gallons Per hour (GPH) fuel usage gauge instantanously monitoring fuel usage while you are accelerating. The Prius powerplant is supplemented with two electric motors which in theory are very efficient and have a very fast power curve(which are suppose to compensate for the slower response curve of the Atkinson cycle engine ) but in practice --in the real world-- the electric motors power output is limited by the maximum draw/load of the NiMh battery pack they depend on. The Ford C-Max hybrid solves the max load for the electric motors by replacing the NiMh battery pack by a more powerful Li-Ion battery pack. But because the C-Max is much heavier - the penalty for hard accelerations for the C-Max is going to be much more significant than for the Prius v which is a lighter vehicle. Designing a car is a very complex balancing act - it doesn't take much to fall off the tightrope.

    I believe I sort of understand the conundrum but I don't have any answers..:rolleyes:
     
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  6. walter Lee

    walter Lee Hypermiling Padawan

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    What does he know that I don't know? o_O
    How does he do that? :confused:
    That's incredible! That's impossible! o_O
    How can I get some of what he's having? :p:coffee:
    Enterprise is renting out Prius - maybe if I rent one out for a weekend or maybe week I see if I can get similar results...:cool::D
    Oh Jimmy Crickets! This isn't working out... :notworthy: :notworthy::notworthy:
     
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  7. ystasino

    ystasino Active Member

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    I remember when I first got my genII I would get about 44 mpg. After scangauge and years of experience I'm at 53, year round.

    There is a steep learning curve with any hybrid. First, you have to know what the RPM range that gives the best efficiency. Second you need to know the terrain you're driving so that you can accelerate efficiently when going uphill without losing momentum, and you need to know how to estimate whether rolling down the hill with battery only would maintain momentum. Third, you need to understand that changes in momentum are usually a waste of energy. Fourth, there will be hybrid system-specific differences.

    How does one get the fusion hybrid into "stage 4"? Are you tracking elevation so that you know the steepness of your hills or mountains? Are your tires inflated to at least 42 psi? And like everyone is saying winter time is tough on mpg.

    I bet that early Ford hybrid adopters, and the buffoons who pretend to know what they are test driving, are naive to such details and that 47 mpg is attainable.
     
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  8. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    All of this makes great sense to us hybrid veterans but here's the difference. The Gen II's FE rating was 45 hwy/48 city. Assuming mostly hwy or even mostly city, you were getting very near the EPA with your Gen II. Now your exceeding it by a wide margin.
    These guy/gals are getting 38mpgs in a car that's supposed to get 47. Should they have to learn all these techniques to simply match the EPA? Or... should these techiques allow them to surpass EPA?

    I get what you're saying and I do agree with it but, shouldn't the average driver be able to get w/in 2 or 3 mpgs of EPA? Shouldn't the hypermiler be able to exceed EPA?
     
  9. austingreen

    austingreen Senior Member

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    lol. The gen II had all the magazines greatly under performing the epa just like the c-max. It has a large spread. The gen III closed the gap. YMMV. We can judge real world in a couple of ways.

    1) If you drive the cars the same
    2) If you maximize

    Much of it has to do with the route you drive, even without behaviour.

    I'm getting 42-43 in a car that is supposed to get 50mpg. YMMV. If I take a long trip or go out of my way I can exceed EPA. I talked to some other prius drivers nearby. Techniques don't help you get close to epa with hills, short routes, and a 65mph highway. I know I can add on miles and go out of my way and get 50mpg - I tried to just verify.

    No the epa does not know your route. If you were gettting more than epa in a gen II using techniques though, you should be able to modify these techniques and exceed epa.

    What you can't do is drive the c-max like the gen II, or relly on car mags or the epa. YMMV
     
  10. a priori

    a priori Canonus Curiosus

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    The early EPA numbers for the Gen II were around 60MPG, as I recall, and not many people got very close to that predicted FE. I didn't, but I found it nearly impossible to go below 50MPG, except in the winter time. I have a short commute and live in a northern climate, but I don't have hills to contest with every day.

    The Gen III "closed the gap" by engineering changes that help people with shorter commutes and colder climates. It still doesn't change what hills will do to FE. The gap closure also had a lot to do with the EPA estimates being brought closer to reality. I've met the EPA numbers in my Gen III, but only barely. This has a lot to do with the fact I have a Model V with larger wheels and wider tires (and a little more weight). I also drive with the climate control always on, so I have heat and A/C going constantly. I use the seat warmers when I want to be even more comfortable, and even though I drive in the right lane and am not a speeder, I don't clog traffic just to get good MPG numbers. I COULD get higher FE, but I chose to use the comfort features of the car -- for my own pleasure and . . . comfort.

    You and I have drives outside the norm, so our numbers are not going to be in the center of the bell curve. The lack of hilly terrain in the midwest certainly helps my cause. I could do better on FE if I doubled my commute distance, but then I'd only be wasting fuel and time (as you've pointed out).

    We won't really know the full extent of the problem with the Ford numbers until we really know there is a problem with the Ford numbers. Now that we are in late November, FE is not going to be improving. My guess is we won't really know the situation until at least July of 2013. I'll agree the initial reports don't look very good, and it has steered me away from the C-Max as an option (as a second car) for now. The smaller cargo area hasn't helped, either, but the fact it doesn't appear to be close to the Prius v in FE really pushed me away for now.

    Still, I'm really hoping things will turn around and we'll see people averaging EPA numbers by next summer. I'm just not going to be one of the people taking that leap.
     
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  11. usbseawolf2000

    usbseawolf2000 HSD PhD

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    YMMV especially when you have the non-OEM wheels and tire size.
     
  12. austingreen

    austingreen Senior Member

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    Since I have asked neighbor prius drivers with OEM tires and similar driving patterns, we can eliminate my wheels and tires as the only factor. None of them gets close to epa.

    It is pretty obvious that the prius will greatly underperform epa significantly on short trips especially with heavy use of heat or air conditioning. That appears to be the most significant factor in YMMV at least here. As I said I can exceed EPA if I go out of my way and avoid the hills, highways and get stuck in traffic. I don't think that would actually significantly improve my enjoyment of the car or gallons per year. Trips to the grocery store and running trail are especially bad.

    I would guess my aftermarket equipment may reduce milesage 5%-10%, while I am getting 20% worse mileage. When I hear about those greatly exceeding epa, they don't have the same driving patterns at all. My mpg is Consistant with the numbers CR and car and Driver got on the gen III with oem tires. My previous car a Lexus GS V8 exceeded its epa, but its epa was much lower than the prius.
     
  13. Sergiospl

    Sergiospl Senior Member

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    I think Prius mpg is well-established; Browse On-the-Road Fuel Economy Data
    Here is a C-Max owner' s opinion!
     
  14. spwolf

    spwolf Senior Member

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    obviously he does not know how to drive the car!!!!!!!!

    it will take at least 10 years to establish the pattern of these new Ford Hybrids


    :)
     
  15. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Ford hybrids getting 38 MPG (what you were replying to) was not for the short trips with heavy use of heat or A/C. The reviews reported those figures have longer drive than that. Of course Prius will not get 50 MPG because that's far different from EPA test.

    I can tell you that aftermarket rims and non-OEM tire size will lower your MPG. Stickier tire compound affects the city MPG more than the highway. I do love the better handling and responsiveness. As I said before, I have love and hate relationship with my 17" Kyowa wheels so I end up swapping it back and forth.

    I did 2 miles trip (20 minutes drive) on gas with my PiP before I was able to charge. I got 38 MPG without using heat or A/C. After I am able to plug it in, I don't use gas any more and I weeded out those inefficient short trips.
     
  16. ystasino

    ystasino Active Member

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    If the 37 mpg holds for warmer ambient temperatures and for many different drivers, then yes Ford might have a serious issue. We also don't know if the estimated mpg is accurate. We know that the 2.0 lt engine is much faster -and thus tempting- than a Prius's. Also the average ford fusion buyer may be thinking that driving it as they drove their regular car would get 47 mpg, while the average Prius driver would be looking for savings and thus bring the actual mpg naturally closer to the EPA mpg.

    It's just way too early to say, I wish I could drive it for a few hundred miles and find out.
     
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  17. spwolf

    spwolf Senior Member

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    maybe they are broken and Ford will fix them.
     
  18. austingreen

    austingreen Senior Member

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    We don't know how they were being driven, other than accelerating faster than the prius v in the magazine reviews where it was spelled out. The prius c was driven long distances too, and low hp means it could not accelerate like the c-max. Still car and driver and consumer reports got 39 mpg on the prius c. I don't expect most owners to get numbers that low.

    There is simply too little data so far, other than a mileage hit above 60 mph as a couple of mags tested 75mph. I was responding to the YMMV. Whenever we have one of these things people drive the non-prius in worse conditions and compare it to prius EPA.

    I never said that my aftermarket equipment did not affect mile mileage, what I did say was the hit was much worse for my driving pattern. What is not spelled out by all the fan boys is short trips and hills make mileage in the prius much worse than epa. Others with oem equipment get similar hits to mine. I did not experience the same hit in my previous car, as I'm sure that big old 4L V8 warmed up fast and had plenty of power for my hills. I accelerate much more gently in the prius too.

    YMMV

    I'm sure electric miles would help my mpg. Note, I often take 5 minute 3 mile trips. Ken advised on how to fool the ecu, but I don't really want to do that to my car.
     
  19. ystasino

    ystasino Active Member

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    I don't have any stake in Ford, but my Gen II has had reliability issues with the squealing brake fluid pump, the twice recalled inverter pump, the steering wheel recall, the (ridiculous) gas pedal shave recall, a dying front passenger side window mechanism, and a melting trunk opening assembly. So I'm willing to cut Ford some slack on that one too...
     
  20. Sergiospl

    Sergiospl Senior Member

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    I hope it is not 37 mpg, because 10 mpg difference is 21% less. The ES 300h/Camry hybrid have a bigger 2.5L/200 hp versus the 2.0L/188 of C-Max/Fusion. Your MPG Estimates Your MPG Estimates
     
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