Sunday, September 16, 2012

The New 54.5 MPG Mileage Standards

A couple of weeks ago, the Administration announced a new CAFE (Corporate Average Fuel Economy) mileage standard for the year 2025, 54.5 MPG.  Note that the "Average" in there explicitly says that every vehicle in the manufacturer's lines doesn't need to get 54.5 MPG, just that a manufacturer's fleet average needs to hit this magic number.  Cars are treated differently than trucks, and one of the reasons for the explosion of SUVs is that they are counted as trucks, while station wagons were counted as cars.  Not many station wagons being made these days.  There is great legal wrangling and fighting over how to classify any given vehicle because not every vehicle has a prayer of hitting that kind of mileage

The NHTSA press release touted:
  • A savings of more than $1.7 trillion dollars in fuel costs, or an average fuel savings of more than $8,000 by 2025 per vehicle over its lifetime,
  • A dramatic reduction in reliance on foreign oil to the tune of 12 billion barrels of oil a year, or 2 million barrels a day, of oil imports, by 2025
  • Reducing greenhouse gas emissions from cars and light trucks by 6 billion metric tons, or more than the total amount of carbon dioxide emitted by the United States in 2010
  • Does anyone besides an engineer ask how much we need to spend to save $8000?  It's going to be free, like the free candy from unicorns that poop skittles?  No?
    Design News reports this week that there have been a couple of engineering consulting groups  studying just what it takes to increase CAFE to that level.  The government says it will add $2500 to the price of the average car, but the Center for Automotive Research (CAR, of course), disagrees, saying it could hit $11,000 to save that $8000.  Scenaria, "a consulting firm specializing in the study of technology investment decisions, contended that the figure would minimally reach $5,000 per vehicle, and might hit more than $8,000 on many models."  Are you sure you want to spend $5000 to save $8000? Sounds better than spending $11,000 to save $8000.
    Consultants also worried about the rule's effect on the market for new vehicles. "When you reach 35, 40, and 50 miles per gallon, the cost to achieve it gets too high," David Cole, chairman emeritus of The Center for Automotive Research (CAR) and a former professor of automotive engineering the University of Michigan, said in an interview. "And the value returned to the customer gets to be less and less. The risk is that people will say, 'Why should I buy a new car? I'll just keep the old one. It's a better business decision.' " 
    CAR also analyzed how much the annual fuel cost is for 15,000 miles of driving, and posts this graph of cost vs. MPG for three different fuel costs.  They all share the shape of a curve of diminishing returns, and even at $5.00/gallon, the savings aren't very great as mileage goes beyond about 30.  For example, the cost of fuel at 20 MPG is 50% higher than 30 MPG, but from 30 to 40 the fuel cost is only 33% higher. 

    The laws of physics can only be broken in advertising (and Looney Tunes).  To deliver the power it takes to move big things requires power out of the engine: long piston strokes, large pistons, large engines, lots of torque.  The internal combustion engine has been optimized as a system for about a hundred years, and you're not going to suddenly make it 70% more efficient (the difference in CAFE standards from now to 2025).  Instead, to reach the new standard the cars will get lighter, with more plastics and thinner metal structures.  The shorter way to say that is they'll be less safe.  These new standards will cost more lives. 

    In a rambling rant a month ago, I commented on a similar situation with the regulations that essentially outlawed top-loading washing machines, and how our single-minded bureaucracies always think they know better than the market.  I've got news for the administration: a real half ton pickup (the most common size) that got twice the current MPG would be snapped up so fast it would set every truck sales record imaginable.  Nobody's against that.  We're just against being forced to pay more for a flimsier, less safe vehicle than we save by buying it, and we're against getting stuck with one that doesn't do everything we need it to do.



    1. Getting those "last few per cent" of *anything* always incurs a cost way out of line with getting the first few.
      Maybe these morons can just repeal the laws of Thermodynamics, and we'll all benefit every where, every time, forever!

    2. I think it was somewhere around 1986 or so that it was pointed out that CARB-standard cars were performing as mobile air filtration devices in the LA basin, emitting cleaner air then they took in. The suggestion was made at that time that, instead of bludgeoning car companies for still cleaner cars, it would be more efficient for CARB to simply buy brand new models and exchange them for free with any car more than 6 years old.

      The same is true, I think, with the government's mileage wars. Trading a 14 mpg Buick for a 30+ mpg Civic or Camry would lower national consumption overnight.

      But I doubt lowering consumption, while a stated goal, is the primary reason for the effort.

    3. The laws of thermodynamics are discriminatory, no one is allowed to tell "The ONE" no. I find that the newer cars do not have much more cargo room than my motorcycle, and aren't all that more efficient. If you have more than 2 children do you drive 2 cars, or will that be factored in, along with the lack of luggage, and overall crampedness brought on by these plastic "vondervagon"s, I do like higher MPG's, and cleaner air but at what cost?, and by who's instructions?
      IIRC mopar had experimented with a gas turbine electric vehicle back in the late 50's and wasn't able to coordinate the DC motors, with computer assist I think it might work at this time. Constant speed turbine(little jet engine) diving a generator powering DC motors at the hub might be the ticket, who knows?

    4. The Chrysler Turbine Car used a standard TorqueFlite transmission with a gear reduction box between the engine and the transmission.
      The power turbine ran at about 45,000 RPM, and the gear box was about 10:1.
      No electric motors used.
      What killed it was the high cost of manufacturing it, and the very high NOX emissions caused by the high combustion temperature.
      Back in the 70's when I was working at Fermilab, a buddy of mine and I had a standing joke about everybody's house would have it's own mini sewage treatment plant that would capture the methane, and use the methane to fuel a small turbine running a generator to power their house.
      It wouldn't be much of a stretch to use a small turbine spinning a generator to power a car.

    5. I have been wrong before, but still why not try again. Turbine electric seems to work on marine applications, downscale, use ceramics, and try it. I don't have any answers just sugestions, and banging heads against wall, repeat until new answer arrives ain't getting it.

    6. Turbines work excellently for applications that run at a fixed load/fixed speed. The classic "automotive" turbine like Chrysler built was an attempt to overcome some of the problems with using a turbine in an automotive application. Namely, a load cycle that was anything but fixed, or operating over a narrow speed range.
      A small turbine running a generator/alternator to recharge the batteries in an electric vehicle, and to supplement them, could be a game changer.
      The problems in mass production of small turbines on the scale that the automotive industry would require some clever thinking, and materials research.
      I'm not knocking your idea, just saying it would take a bit of effort. I think the bigger problem is the entrenched thinking in Detroit; If it doesn't have pistons and a crankshaft, it's not an engine, and isn't worth any thought.

    7. "Instead, to reach the new standard the cars will get lighter, with more plastics and thinner metal structures. The shorter way to say that is they'll be less safe. These new standards will cost more lives."

      What makes you think they'll relax crash standards one iota?

      These regulations are made by people who think you just snap your fingers and say "Lux fiat!" and the universe orders itself to your desires. They would vote on what pi should be and then demand it be made so.

    8. I've mentioned this here before - a small, one-RPM turbo diesel driving an alternator, coupled with a small battery pack to handle short high drain demand (rapid acceleration which requires more current than the engine/alternator system can handle) and a double shaft motor driving both rear wheels is, I think, a potential solution that could yield pretty high MPG.

      Might a turbine be better? Could be, I have quite a bit of knowledge about internal combustion reciprocating engines, gas turbines not so much. But, diesel has infrastructure: fuel is sold pretty much everywhere, a lot of mechanics can fix them, and there's a wealth of engineering talent to apply on the design end. Given marine genset technology, there might be a few foundation platforms already in existence to begin with.

      Turbines might be better in the long run - I don't know - but it'll take a while to build the infrastructure to support them.

      I also think that drjim and Tam are correct: If a big leap in technology, or a completely new application of existing technology, is the answer it won't come from Detroit. And, bureaucrats in Washington will find new and innovative ways to strangle it in its crib.

    9. I agree about a small Diesel spinning a generator, and the fact that getting small turbines into production could be costlier than a small Diesel. Diesel technology has been around a LONG time, and the knowledge from stationary power plants/generators would apply directly.
      The nice thing about using an ICE as a generator is that they can be optimized for running most efficiently at a single speed, rather than being throttled, which always cause a loss of efficiency. Most ICE's (normally aspirated, anyway) have lowest specific fuel consumption at the point where their volumetric efficiency is highest, usually very close to where the engine develops peak torque.
      A number of the Foss tugboats being used in the L.A./Long Beach harbor are using a "hybrid" technology that involves Diesels and battery packs, but I don't know very much about them. I'll SWAG it that that's the type of marine application you're alluding to.

    10. drjim - Actually, I was thinking about diesel gensets used on smaller marine craft. A number of years back I saw some small (about 1.5-2.5 liters, IIRC) German and Japanese diesels driving 15-40KW alternators on some boats in the 80-120 foot range.

    11. Ahhhhh....gotcha.
      I'd forgotten that most ships have a separate genset, or two.
      That's a good example. I'm sure the engines are optimized for that use, and probably get quite good bsfc.

    12. I just want to say I can't add anything to this, but I've enjoyed all of the conversation!

    13. Incidentally, I believe Jag was working on a small turbine setup for their extended-range plug-in hybrid supercar, but decided it wouldn't be ready for prime time in time for the model's launch.

      It'll debut with a conventional small turbo four-banger while development work continues on the little jets.

      1. That would be cool to see... A little search fu leads to a Jaguar C-X75 that seems to match your description. 200,000 pounds, which is north of $320,000 today.