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Scientists Claim Major Leap in Engine Design 775

An anonymous reader writes "Purdue researchers say they have made a major advance in the design of the internal combustion engine, one that could seriously boost fuel efficiency and cut emissions. A key portion involves building intake and exhaust valves that are no longer driven by mechanisms connected to the pistons, a departure from the way car engines have worked since they were commercialized more than a century ago. 'The concept, known as variable valve actuation, would enable significant improvements in conventional gasoline and diesel engines used in cars and trucks and for applications such as generators, he said. The technique also enables the introduction of an advanced method called homogeneous charge compression ignition, or HCCI, which would allow the United States to drastically reduce its dependence on foreign oil and the production of harmful exhaust emissions. The homogeneous charge compression ignition technique would make it possible to improve the efficiency of gasoline engines by 15 percent to 20 percent, making them as efficient as diesel engines while nearly eliminating smog-generating nitrogen oxides, Shaver said.'"
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Scientists Claim Major Leap in Engine Design

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  • by r_jensen11 ( 598210 ) on Thursday May 10, 2007 @05:40PM (#19075105)
    Are they going to do anything useful, like, say, actually boost milage? Or are they going to continue what they've been doing and just increase horsepower and torque?
    • Nah (Score:5, Insightful)

      by damacus ( 827187 ) on Thursday May 10, 2007 @05:46PM (#19075197) Homepage
      All the benefits will be squandered on making bigger, heavier vehicles. At least, that's what's been happening with improvements in efficiency since the 80s. Sigh...
    • by hey! ( 33014 ) on Thursday May 10, 2007 @05:46PM (#19075205) Homepage Journal
      Well, the scientists think the companies will use this to boost mileage.

      Reminds me of a play we had to read in 1960s grammar school about nuclear war. Big scary Atom Bomb threatens everybody, but he is driven away by Atoms for Peace (the script called for a costume kind of like lady liberty, complete with torch, except white instead of green). You see Science was bringing us limitless power, and that was going to eliminate poverty. Since nobody was poor, nobody had a reason to fight.
      • Re: (Score:3, Interesting)

        Of course, better efficiency just means more people before we strip the planet of resources. Anyway, I don't want a more efficient engine. I want a smaller, more powerful one, so I can buy a plug-in-hybrid and seriously reduce oil dependence. We need more room and weight for the batteries, not a more complex, bigger more efficient engine. If I can do most of my driving around town off the grid, it wont matter much if I get 20 MPG or 50 for the occasional road-trip. With 9KWH A123 Systems battery, an 80
      • Re: (Score:3, Insightful)

        by adrianmonk ( 890071 )

        Well, the scientists think the companies will use this to boost mileage.

        Yeah, and the scientists who developed silicone breast implants thought they would be used by breast cancer victims who'd had mastectomies and just wanted to look normal again.

        Well, I'm sure they had some idea, but that was the intent at least.

    • by Sciros ( 986030 )
      Haha I'd be happiest with both. A properly-powered SUV like an Xterra could benefit from better mileage. But better mileage on a Z06? Psh that's like asking for a hockey player to have better teeth :-P

      You do have a point, though. Personally, and because I'm in a cynical mood at the moment, I think that those folks who get paid big bucks to do R&D on, or lobby for, alternative fuels, might try to bury this so they can avoid any budget cuts. Hopefully not, though. From what I've read, at the moment hybrid
  • Related story (Score:4, Informative)

    by ajs ( 35943 ) <ajs AT ajs DOT com> on Thursday May 10, 2007 @05:42PM (#19075137) Homepage Journal
    Slashdot had a related story [] a while back on increases to engine efficiency. Not sure if it's related.
  • But they don't actually talk at all about how they WILL drive the cams. And for that matter, they still have cams! Driving valves with solenoids somehow would be more meaningful. If they're keeping the cam, then they can have variable timing easily enough, but they're still going to need a bunch of additional hardware to control lift and duration. Of course, it takes a lot of power to use solenoids to drive the valves, which is why they're not doing it now. Personally I'm far more interested in Coates rotary valves, which have been used in racing. They let you raise RPMs dramatically without having an exploding valvetrain. Combine that with direct injection and I'll be pleased as punch.
    • by TempeNerd ( 410268 ) on Thursday May 10, 2007 @05:53PM (#19075323)
      The also haven't built anything - just modeled it on a computer.
      They may not have solved any of the actual implementation issues, nothing in the article said they had.

      I don't wish to belittle their design ideas - but it is usually very difficult to go from a revolutionary engine design to an operational engine. A good example is the Stirling Engine, great design - difficult to realize.

      I wish them luck - but not going to hold my breath for this one.
    • by theguru ( 70699 ) on Thursday May 10, 2007 @05:53PM (#19075345)
      Why keep a cam if you're electronically controlling the valves? Just like ignition systems have gone to fully solid state, with very few cars having distributors any more, why not move to fully digital timing?

      The cam/valves are really the last mechanical part of the loop. The fuel/air mixtures are now fully controlled by the ECU, and can change on the fly to adjust for altitude, temperature, manifold pressure (turbo and supercharged systems), and the octane of the fuel. As I mentioned above, the spark systems are now fully controlled by a computer, and advance or retard the cylinder ignition, sometimes in conjunction with the fuel curve, to best burn the fuel/air mixture. Being able to dynamically change the valve timing, opening, closing, overlap, duration opens up even more possibilities for tuning and timing an engine.
      • Why keep a cam if you're electronically controlling the valves? Just like ignition systems have gone to fully solid state, with very few cars having distributors any more, why not move to fully digital timing?

        I don't know if you've ever had to compress a valve spring, but they're pretty pissed off devices.

        The best thing we could do would be to move to some kind of rotary valve system - any kind, really. Because reciprocating valves have problems. They are what limits RPMs, which is why rotary engines have been known to reach over 10,000 RPM, and why a [very very built] small block tchevy :) with a Coates rotary valve system [] has reached over 12,000 RPM (can't find cite for that, but their page says "The comparative efficiencies of the spherical rotary valve combustion engine have enabled engine speeds of 14,850 RPMs."

        We could make smaller, even more efficient engines by increasing RPM, but we don't do that because it causes valvetrain death. In order to get high RPMs, you need to be able to open and close the valves faster. Cams only open valves; springs shut them. This has two effects; one, there is a hammering process that goes on between the valve and the seat. Two, if the springs are not strong enough, they do not push the valve closed fast enough, and you get a phenomenon called "valve float". Solenoids can provide infinitely variable valve timing and duration, and through a shifting system (where the whole actuation system moves) you can provide variable lift. But as you increase RPMs, you need to increase the spring rate, and therefore you need stronger and stronger solenoids.

        A solenoid valvetrain has been used in racing (I forget by who) but no one has managed to make a system suitable for the street yet. That's really too bad, because you could eliminate most of the valvetrain that way. But there are definitely serious implementation issues. Rotary valves are here now. There are competing designs, but none with pictures as pretty.

        • by DigiShaman ( 671371 ) on Thursday May 10, 2007 @06:53PM (#19076149) Homepage
          You want an engine that makes peak HP with the lowest RPM level possible for two reasons. 1st, engine wear (think RPM squared). 2nd, fuel efficiency. Even with the best dynamic valve timing, you will achieve maximum burn and emissions the longer the gas has time in the combustion phase. While you can make lots of power in the high RPM band, you'll sacrifice fuel efficiency and emissions. It's always a trade-off which is why we have open and closed loop ECU algorithms in place.

          While I like elegant design of the Coates cam for racing, it's not a practical solution for the mass auto market. Keeping a constant seal with oil is a problem without having it sucked into the combustion chamber. This would lead to carbon fouling. Also, the cam is static, not variable like the proposed system (and the previous V-Tec systems) which poses a major problem for reducing emissions while maintaining a beefy power curve.
        • Re: (Score:3, Interesting)

          and I wonder how long till these are perfected so they do not break often?

          One of the biggest problems with newer cars is that one needs to hook up the computer to fix them. And the computer is not always correct. I had an intermittent problem with the car almost stalling out. I would be driving at 55 mph for a while (30 min, 2 hours+) slow down for a toll (didn't have to stop easy pass) hit the gas to go again. The engine rpms would drop to under 100. I usually took my foot off the gas then hit it again. Ta
          • Re: (Score:3, Interesting)

            by karnal ( 22275 )
            Actually sounds like you need to find a mechanic that can look at the whole picture and not just concentrate on the compy.

            Of course, when you find that one, send him or her my way - I've not found anyone like that yet. I'm trying to learn though...
        • Re: (Score:3, Informative)

          by tbuskey ( 135499 )
          You're looking at car engines, right? My 1982 Honda CB900 redlines at 12,000. Around that time, Honda had a 500cc GP bike that had a powerband between 22,000 and 24,000 rpm. V4, oval pistons, 8 valves per cylinder. It made it to production as the NSR500.

          On another front, cams can close valves too. Ducati uses a desmodramic(sp?) system that doesn't use valve springs at all. It was developed at a time when the metallurgy to make springs meant lots of compromise. Desmodromic means no vavle float. Ducat
    • by Anna Merikin ( 529843 ) on Thursday May 10, 2007 @06:00PM (#19075447) Journal
      In Formula One racing, motors have featured compressed air to open and close the poppet valves. This is related to that development, at least 20 years old. It makes valve timing independent of crankshaft angle, so maximum efficiency can be reached at any or all engine speeds. Parasitic losses are less, and so is weight, the cam, cam drive and other associated rotating parts can be replaced with air or oil operated solenoids.

      The other "development" you mention is that adding water to the combustion process allows a higher compression ratio to be used without the risk of preignition or knock. This results in more (and more even) combustion pressure, meaning more torque everywhere from the same amount of gas. This method is very popular among drag racers, and is sometimes used with air/water injection into a turbo- or supercharger's plenum to keep the pressurized air from becoming uselessly hot before compression in the motor.

      Rotary valves are a much older development. They have no history of producing more power or reliability (or even efficiency) than traditional valves. Of course, there is no reason they should. Both of the above techniques combined might double the efficiency of the internal combustion engine.
  • by jimicus ( 737525 ) on Thursday May 10, 2007 @05:43PM (#19075145)
    Nothing spectacular about changing the timing on the valves depending on how the engine's being driven: []

    According to Wikipedia, VVT has existed since the 1960's. The only improvement I can see (and that's from reading between the lines) is that they've developed a means of controlling it more precisely.
    • by jfengel ( 409917 ) on Thursday May 10, 2007 @05:55PM (#19075375) Homepage Journal
      That's pretty much standard stuff in science reporting these days:

      1. Scientist develops an improvement in an old but unused technology.

      2. Nobody had ever heard of the old technology, so they can't explain the new stuff until they explain the old stuff.

      3. The press writes about the old stuff, not realizing that it's not news.

      Plus bonus step 4: scientist, trying to ensure that grants continue, points out that eventually there's a major improvement to be made, which the press promptly presents as "imminent".

      You see this all the time on Slashdot, especially in conjunction with solar-cell stuff. There's news there, but it's not what the press is talking about, because the actual news is less interesting.
  • Nothing new (Score:3, Insightful)

    by Oz0ne ( 13272 ) on Thursday May 10, 2007 @05:43PM (#19075151) Homepage
    Toyota and Honda have both been leveraging variable valve timing techniques to boost performance and efficiency for over a decade.

    The big difference here is that finally someone realizes we can do that independent of crankshaft, pistons, and cams.

    It's a simple concept really, monitor your engine and control the valves on solenoids digitally and you can achieve monumental performance, efficiency, and emmission improvements. It's really just a matter of making the concept cost effective to produce.
  • Most cars have some forum of variable valve timing already. If this is radically better it will need to be a lot better.

    If this can increase fuel efficiency and give the sort of performance you get from a Wankel engine as used in the Mazda RX8 then this will be welcome.
    • Re: (Score:3, Informative)

      by drinkypoo ( 153816 )
      The RX-EVOLV in the RX-8 falls significantly short of original projections and the vehicles have a tendency to get poor mileage. It would be better to make a comparison to the pissed off TT motor in the late model RX7, which actually has more power. That however was turbocharged. But then again, I like turbocharging/supercharging.
  • Lipstick on a pig (Score:5, Insightful)

    by tinrobot ( 314936 ) on Thursday May 10, 2007 @05:46PM (#19075209)
    No matter how efficient an internal combustion engine gets, it will still emit carbon dioxide. While this technology might help an engine spew less carbon dioxide, it's still a dead end -- kind of like putting lipstick on a pig.

    Put the effort into other forms of energy and we'll be a lot better off a lot more quickly.

    • by drinkypoo ( 153816 ) <> on Thursday May 10, 2007 @06:08PM (#19075555) Homepage Journal

      No matter how efficient an internal combustion engine gets, it will still emit carbon dioxide.

      No matter how much carbon dioxide an internal combustion engine emits, the fuel consumption will still be carbon-neutral if it's running on biofuels.

      Put the effort into other forms of energy and we'll be a lot better off a lot more quickly.

      We have a huge fueling infrastructure that is not simply going to go away overnight, and internal combustion engines will be here (on Earth) for a long, long time to come. Making them more efficient is probably a good idea.

  • Been done (Score:3, Informative)

    by OnlineAlias ( 828288 ) on Thursday May 10, 2007 @05:46PM (#19075221)

    Why does this warrant such a sensational article? Racing engines have been actuating valves pneumatically for years and exhaust gas recirculation has been around forever too. Hell, Honda's old CVCC used a similar exhaust technique back in the 70's.
  • 1. GM buys technology
    2. New efficient engines are developed and promoted
    3. Next generation of cars have negligible improvement in fuel economy
    4. ???
    5. Profit!!
  • Trying to improve the efficiency of ICE engines is good as a short-term solution, but eventually we will need to wean ourselves out of petroleum. I know the subject has been hammered onto every slashdotter's heads, but I think BEVs [] are the way to go.
    • by drinkypoo ( 153816 ) <> on Thursday May 10, 2007 @06:15PM (#19075659) Homepage Journal
      The problems with batteries are that they have poor energy density (even the theoretical energy density of a chemical battery is less than that of gasoline) and that they take a lot of energy to produce. They also tend to be based around substantial quantities of toxic, polluting materials; the refinement of those materials is further detrimental to the environment. Fuel cells with liquid fuels produced by nuclear, solar, wind, hydro, or biofuels (or taking biofuels directly) do much better along potentially all of these lines.
  • How appropriate! the Boilermakers finally come through...
  • by 0WaitState ( 231806 ) on Thursday May 10, 2007 @06:08PM (#19075563)
    from the blurb:

    ...which would allow the United States to drastically reduce its dependence on foreign oil...

    Editor doesn't know much 'Murkins, does he? This will be used to create higher-horsepower, heavier cars, not more efficient ones. Coming soon: The Hummer Canyonero-Magnum!
  • by Nom du Keyboard ( 633989 ) on Thursday May 10, 2007 @06:11PM (#19075603)
    This doesn't sound that new, at least not in concept. Actuating engine valves with something other than camshafts, lifters, pushrods, and rocker arms as been around as an idea for a long time. I recall a Tucker prototype engine in the San Diego Automotive Museum (Balboa Park) that explored that concept. And Honda VTEC, IIRC, varies valve timing based on RPM.

    Yeah, mechanical valve actuation has its problems. It makes for either non-optimal valve placement (standard wedge heads) or overly complicated mechanical actuation trains (see Chrysler original Hemi engine design). So a better method to actuate valves than driving it from a fixed, or fixed-variable, design could make for better engine performance overall. That's hardly new. As best I've seen, this has been merely an engineering problem to determine a better way to actuate valves that meets the requirements of cost, durability, cost, performance, and cost -- when it comes to consumer engines. While such an actuator method is certainly significant news in and of itself, it's not like someone has redone the whole engine.

  • by Animats ( 122034 ) on Thursday May 10, 2007 @06:28PM (#19075859) Homepage

    The trouble with direct valve actuation is making an actuator that's fast enough, powerful enough, small enough, heat-tolerant enough, and reliable enough to do the job. Cheaply. This is not easy. Prototypes have been built [], but it's still not something that's easy to do. BMW did quite a bit of work in this direction, but backed off to their "Valvetronic" scheme, which still has a camshaft with other components to give some adjustment potential.

    Most of the existing schemes for tweaking valve timing still involve camshafts, but there's an additional mechanical linkage which allows adjustment of phase angle, valve travel, or both. That's an idea which goes back to steam engine design. Most of the gear on the side of a steam locomotive is there to adjust valve timing. Steam engines are controlled by valve duty cycle, not throttling. This was the original pulse-width-modulation system. On steam engines, valve phase can be adjusted far enough to reverse the engine, which is how locomotives back up. Some newer marine diesels have that feature, too. Eliminates the need for a reverse gear.

    So this isn't a new idea. It's an old idea that's hard to make work cost-effectively. Somebody may crack this thing; it's a tough mechanical engineering problem, but not an impossible one.

  • Pointless (Score:4, Interesting)

    by twifosp ( 532320 ) on Thursday May 10, 2007 @06:34PM (#19075939)
    Improving a piston driven engine is absolutely pointless. There are already moer effecient alternatives out there.

    Such as the Quasiturbine engine []

    Or the wankel, or Rotary, engine which is even used today. While the rotary might not get better gas mileage than a piston engine, it certain produces more power per displacement than a piston engine. Furthermore, the newest rendetion of the wankel, the Renesis, developed by Mazda already uses some of the benefits that this engine supposedly does. Namely with the exhaust ports.

    The design of the piston engine is flawed. Moving up and down robs your engine of momentum and is just plain silly. Going around in circles produces much more power. If only the Wankel engine, or better yet, the quasiturbine engine had as much R/D put into them as piston engines, we'd have a lot better combustion based engines.

    • engine displacement (Score:5, Informative)

      by Anonymous Coward on Thursday May 10, 2007 @08:08PM (#19076997)

      While the rotary might not get better gas mileage than a piston engine, it certain produces more power per displacement than a piston engine.

      Well, no actually. A rotary such as the current Mazda 1.3 litre simply spins faster than the equivalent piston engine. The volume passed per unit of time is the relevant comparison, not the static displacement.

      Since the RX8 competes with similar HP sports cars by guzzling at SUV rates, it indicates Mazda's best effort so far is still inferior in power conversion of the gasoline. (Though the smoothness is great fun.)

      As for turbines, same deal really. The aircraft turbine has yet to match piston engines on efficiency for short flights. You have to run long-haul at cruise altitude before the overall fuel consumption is lower.

      The idea of a completely spinning engine is very seductive, but the actual results of forty years of careful research has not delivered a spinning engine that's better than the 'tossing potatos'. This is counter intuitive, and it's entire worth your while to dig into the studies to find out why that is.
  • Prior Art (Score:3, Interesting)

    by sunderland56 ( 621843 ) on Thursday May 10, 2007 @06:40PM (#19076027)
    Boy, this sure sounds a lot like what Valeo announced last year [].
  • by dltaylor ( 7510 ) on Thursday May 10, 2007 @07:25PM (#19076551)
    This article, as has been, and will be, pointed out throughout the comments is not news, very interesting, or likely to yield much of practical value.

    Non-crankshaft-linked valve timing, whether through variation mechanisms that are in current street car use, or electric/pneumatic/hydraulic actuators, such as the F1 engines have used for years do not solve the problem of heat control. Burning fuel (which is why some parts of the combustion chamber are hotter than others; get a clue) generates heat. Some of that heat expands gases to push pistons (or rotors) and a lot of heat raises the temperature of the engine components. Without cooling the engine, the accumulated heat destroys the materials. This is why my air-cooled Ducati engine has a lower power output than the water-cooled Ducati engine of the same (roughly) displacement. The water-cooled engines can keep the components at a lower (and more consistent, I know) temperature, so they can use more air and fuel to generate more power (the extra valves are only usable because the additional heat can be managed).

    The real solution is to use more of the chemical energy to provide power for moving the vehicle and less of it to heat the components. Trying to store the energy in rechargeable batteries will result in mostly short-range urban and novelty vehicles for a very long time, since the energy density of the storage, both in mass and volume, and recharge rate are pathetic compared to diesel, gasoline, or compressed propane/methane.

    The "hydrogen solution", applied as an internal combustion fuel, has the same problems, plus the additional headaches of generating the hydrogen ("but solar is cheap" - and it will compete directly for surface area with homes, farms, and the large-scale installations needed to power your iPod's recharger since we'll be trading power between sunlit and darkened regions) and transferring it between fuel station storage and vehicle storage. Hydrogen fuel cells, still with the generating, storage, and transfer problems, are pretty good at converting between chemical and electrical energy, and electric motors are usably efficient at converting electrical energy into motion.

    What we need are fuel cells that can handle ALL of the chemical energy in a hydrocarbon fuel, converting not just the stored hydrogen and oxygen from the air into water (2 H2 + O2 = 2 H2O; put energy in to break up the hydrogen and oxygen molecules then get energy back by combining the hydrogen and oxygen atoms into water), but also using the carbon atoms in the fuel molecules to make CO2 which gives a larger net energy output by mass of fuel.

    As for "CO2 is a greenhouse gas": So what? We're already too far down the path. The paleohistoric record of ice-age cycles shows that we have already passed the inflection point to cooling while we're accelerating the heating. If you want to reduce the CO2 footprint of humans, along with ending overfishing of the oceans, sucking the deep aquifers dry, destruction of the rain forests for farmland, habitat destruction for either human use or by diversion of fresh water resources, pollution by agricultural runoff, ..., reduce the number of humans by 6 billion, or so. Unless you do that, nothing else will matter. Additional terrestrial hydrocarbon fuel resources are becoming quite hard to reach and there's too much demand to get by easily on biological sources alone. Improving the efficiency by which we use the fuel helps us, regardless of the other issues.
  • by avxo ( 861854 ) on Thursday May 10, 2007 @07:28PM (#19076581)
    I'm sorry, but variable valve actuation is not a major leap today. It was a major leap a decade or so ago.

    Indeed, Renault had been actively researching electromagnetic valve actuation and infinitely variable lift and timing systems for their F1 engines since at least the mid 90's. I believe that at least some of their engines have used such electromagnetic actuators in the past, in combination with pneumatic springs (which are not really "springs" in the traditional sense, but function in a similar way) although I can't find a specific reference to that effect.

    And then, of course, there is Valeo. You see, in 2005, at the Frankfurt Motor Show, it introduced a system that replaced camshafts with electromagnetically actuated valves and it claims that it will be available to manufacturers in volume in 2009. More details, including a pretty image, can be found here [].

    Now, coming up with smarter management software (which seems to be implied by the article), that can take advantage of per-cylinder (and per-valve) actuation by using such tricks as re-introduction of exhaust gases from previous cycles into the cylinder sounds very promising, and could help increase power, improve mileage, reduce emissions and lengthen the life of catalytic converters.

  • this is news how? (Score:3, Interesting)

    by OKCfunky ( 1016860 ) on Friday May 11, 2007 @02:32AM (#19079609)
    This has been known for quite sometime now.
    It's nothing new, and hardly something applicable in the short term.
    If it's pneumatic valves, wouldn't last near long enough and prohibitively expensive ala certain Formula engines.
    Electric valves, 24V or any other, do not have the capability to survive in a reliable and flawless manner in a stressful life, i.e. high rpm, high heat, long term capability, all at the same time. When I don't have to fear a solenoid fritzing and nuking a $30K SBC, then I'll make that jump.
    Rotary valves, while nifty, are likewise prohibitively expensive in the short term outside of nicely lined sponsored rides. I'm not looking to blow an easy 60K on a perfectly balanced durable big block to reel 10K. While it'd be cool, theres a hell of a lot cheaper and easier ways to get ridiculous power out of current solutions.

    How about more development into the cerametallic blocks, bore liners, pistons, heads etc. ? It'd be nice to have a ridiculous low thermal expansion rate, so that way you can have a far better seal, higher efficiency, you know... useful things.
  • by KrisJon ( 6582 ) <> on Friday May 11, 2007 @03:35AM (#19079873)
    In 1991 BMW started using variable intake valves. Now both intake and exhaust valves are variably controlled via the DME (brain). You don't even have a throttle in the normal sense, just different valve timing controlled by the computer. []
  • Prior art (Score:3, Interesting)

    by threaded ( 89367 ) on Friday May 11, 2007 @05:24AM (#19080389) Homepage
    I built one of 'electronic-camshafts' in my workshop about 20 years ago, fitted to the engine of an old Honda 2 cylinder motorcycle. The increase in power and efficiency was so startling that I went as far as applying for a patent. Then found it'd been patented about 15 years earlier still. Bit of a waste of time and money. At least nowadays one can sit with a stack of CDs or even Google and search these things yourself.
  • by Tungbo ( 183321 ) on Friday May 11, 2007 @09:51AM (#19082033)
    Why not just use diesel....

The other line moves faster.