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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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    No, because my same argument shows that the Fusion also cannot reach those fuel economy figures just based on ICE-off part of the test.
     
  2. SageBrush

    SageBrush Senior Member

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    This is the EPA test:

    US-06.png

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    Over the ~ 600 seconds of the test, deceleration occurs for about 100 seconds, or 17% of the test. The steady state driving in the low 60's mph would only be an efficient glide in a Ford hybrid if excess SOC was available to use in a power-glide. Even in an optimistic scenario the excess SOC would be used up after a minute, so ICE-off during this test for a Ford hybrid is at most 160 seconds of the 600 second test. That works out to a 3% fuel economy bonus.
     
  3. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    I'll never understand why people don't do a little research if FE is super important to them. Unless they were an early adopter it is widely known that they don't get their EPA.
     
  4. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I think it is due to larger displacement ICE and not having EGR to enable efficient operation at low loads.

    I don't think Ford published BSFC for that 2.0L engine. My guess of min power at reasonable BSFC is 30kW. With that excessive power, it can be used to charge the battery and it shutdown and repeat. This approach takes a hit on conversion loss through the battery. If charging and discharging loss are 15%, the loss would be 28% and add loss from inverter also.

    The alternative is to operate ICE at inefficient load. This appears to be the least efficient choice and unavoidable above 62 mph.
     
  5. SageBrush

    SageBrush Senior Member

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    I'm under the impression that the round-trip around the battery is 15%, not each way. And 30 kW sounds like a lot for an Atkinson engine to reach a low BSFC. You are right though, an engine chart would be very interesting.
     
  6. SageBrush

    SageBrush Senior Member

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    Speaking for myself only -- I thought the early reports were a mixture of aggressive Ford drivers and the winter hit.


    And while I now accept that Ford did *something* to up the EPA results to unrealistic numbers, I remain unsure exactly what was done. The story of using the Fusion hybrid numbers is at best only a partial answer because the Fusion is also over-rated -- somehow.
     
  7. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Charging loss for PiP from wall is about 15%. Battery discharge is about 85% efficient so another 15% loss. I forgot about 5% loss from motor and generator. There is also 5% loss from IGBT inverter to and from motor/generator.

    Total round trip loss add up to about 40%.

    30 kW estimate may be high. Gen2 Prius 1.5L engine has min power of 18kW to get optimal BSFC. 33% more displacement would move it up to 24kW. Assuming Ford Atkinson cycle implementation is as good (close the intake as late) as Toyota.

    What's amazing about the 1.8L ICE in Gen3 is it can go as low as 10kW and still able to get optimal BSFC. That is essentially necessary for PiP to blend with power from plugin battery.

    This also mean Energi plugins from Ford cannot blend since ICE will have excess power most of the time.
     
  8. Troy Heagy

    Troy Heagy Member

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    Yes really. Because Ford *admitted* they just copied the Fusion's 47/47 results over to the C-max, because they didn't want to run the test a second time.

    BTW I don't know why you think Fusion's results are not acceptable? If Prius can get 48 highway & the Accord 45 highway, I don't see anything to stop a Fusion getting a comparable value of 47.
     
  9. dipper

    dipper Senior Member

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    The Fusion mpg numbers are from the old 2 cycle test, not the 5 cycle test. A legal loophole Ford used to allow using these unattainable mpg numbers with the old test cycle. If Prius was still using the 2 cycle test, Prius would still get 60 mpg city for Gen2 (more if used for Gen3). Which Prius got flacked for, which required the new EPA test cycles to start with. I am glad Ford is getting the same crap that the Prius gotten. Welcome to 2007?
     
  10. Trollbait

    Trollbait It's a D&D thing

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    Of the 5 test cycles, only 2 are mandatory. Those 2 are the old test cycles, which, AFAIK, haven't been changed. The after testing math has though.

    My understanding is that for a car run through the 5 cycles, the 2 old cycles are what is used for the base city and highway figures. The results of the other 3 are used to determine an adjustment for those figures.

    A manufacturer has the option to not run all 5 cycles, but just the base 2 and determine an adjustment mathematically. Like was done to determine new numbers for pre-2008 models, but it might be more exacting. So, the 2 cycle route will not give a pre-2008 number now.

    2 cycle only results come out fine for traditional cars. With hybrids and turbos, it can mean an overestimate. This is probably what Ford did with the Fusion. The 2014 model still has the 47 numbers, so, if so, the EPA seems fine with it, but we won't know for sure until 2015 numbers come out to see. 5 cycle testing should be mandatory for hybrids, but I don't see any changes to the regulations taking effect until the 2015 MY.
     
  11. SageBrush

    SageBrush Senior Member

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    Frank from Spain calculated ~ 10% losses from a trip into and out of the battery.

    I agree that M/G/inverter losses also have to be included to get a fair idea about system inefficiency if Ford programming is shunting ICE energy to the traction battery unwisely, but only by the amounts not also lost in a 'usual' ICE->wheels path.
     
  12. austingreen

    austingreen Senior Member

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    Actually not. The fusion epa uses the mathematical fudge factors that convert the prius (genII) from 2 cycle to current epa. In other words the fusion hybrid 47 mpg combined is an apples to apples test with the gen II prius 46 combined using the same 2 cycle test and fudge factors from the epa. The fudge factors were created partially from the gen II prius.

    The biggest problem is that ford, and every other automaker has gotten better at designing for the test. This is not an altogether bad thing, if you have tests that simulate real world driving, but the 2-cycle test does not. The 5-cycle test does a better job but needs much improvement, especially on the city test. All these high mpg cars should be forced to do the more realistic 5-cycle test, and it should be improved more.

    The c-max though fell through a regulatory loophole, which is quite bizarre. The epa let ford use the fusion numbers, which are higher, for the c-max. The new "corrected" numbers come from the c-max doing the same test. This loophole should be closed except for extremely low volume vehicles where cost of testing really does make a difference. The c-max would never fall in that category.
     
  13. Troy Heagy

    Troy Heagy Member

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    "Fell through" is an understatement. Ford never even tested the C-max..... just copied the numbers from the Fusion test.
    Hyundai/Kia also recently got caught, and had to redue all highway MPG by 3 on all cars. They refunded ~$500 which is ridiculous because 3 mpg loss represents *thousands* of dollars in additional gasoline expenses for owners. (Ditto for C-max owners.)
     
  14. SageBrush

    SageBrush Senior Member

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    Perhaps the consumers will catch a clue and buy a car that *actually* gets superior fuel economy next time, rather than be dumbasses who think '45' and '50' are about the same (let alone 35 -40), or only pay attention to highway fuel economy.
     
  15. Troy Heagy

    Troy Heagy Member

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    Yeah sure blame the Victim instead of the Hundai/Kia criminals that false-advertised. The victims had no idea they were being lied to, especially since the numbers have the official backing of a democratically-elected government.
     
  16. SageBrush

    SageBrush Senior Member

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    I listened to these same 'victims' poo-poo the EPA numbers of the Prius for a decade, and howl in merriment as Honda's IMA came up short.

    It wasn't blind trust in the EPA that led the turkeys off the cliff, it was a mixture of penny pinching and brand choice. Sucks to be them (and you, if I remember your past trolls.)
     
  17. austingreen

    austingreen Senior Member

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    Troy that is the regulatory hole. The EPA made testing similar cars with the same and transmission and similar weights optional. As Car and Driver stated when they created this rule, they weren't thinking about efficient cars. If you labeled a car 16mpg and it really gets 15 mpg, no big deal (or so the regulators would say.) ymmv. Difference in fuel between 47 and 43 on a car going 150,000 miles is about 300 gallons lifetime. But the payments ford made were for good will, there was nothing illegal about the labels. Hyundai/Kia illegally tested their cars. Many that bought the c-max already knew that it was unlikely to hit epa. Was ford unethical in the testing, abolutely, but it was perfectly legal. Bad move on ford's part, the law should be changed that all these cars need to go through 5 cycle tests, and remove the math fudge factors. Was ford the worst car company in unethical behavior? Let's just point out that Toyota perfectly legally refused to bring readers to customers to see the black boxes in unintended acceleration cases. When this was stated in court that the reason was to protect the users privacy, when it was the user that was asking for the test, things got hot for toyota. They have now dropped this practice, but it is just one of the unethical behaviors that they exhibited that drove up the costs of their unintended acceleration case. The bigger cost, was hiding safety information from regulators on sticky pedals. That was illegal, and they were fined for it, but also when caught increased the skeptism of toyota being truthful on safety issues that cost much more.

    Bad on Ford. Bad on the EPA. The law needs to be changed to close these loopholes, but the tests should also be changed to be more realistic of driving in 2013.
     
  18. Troy Heagy

    Troy Heagy Member

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    Sagebrush is still blaming the victims (who believed the EPA numbers of 47/47) instead of the companies. I can easily imagine him saying something like, "She shouldn't have worn that slinky black dress," rather than blame the criminal.

    Toyota also had that engine sludging issue they refused to fix. Tons of engines dying at only 20 or 30,000 miles and Toyota responded by voiding the warranty on customer cars (even when the car had proper oil changes). The issue went on for a decade & the class-action lawsuit involved 4 million customers. It is simply Wrong to advertise a 100,000 mile warranty for an engine & then refuse to honor the warranty when millions of engines start dying early
    .