By on November 8, 2009

Next big future? How many times have we heard that before? [Thanks to MMH for the link]

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29 Comments on “Ask the Best and Brightest: Wave Disc Engine?...”


  • avatar
    cwmoo740

    That thing doesn’t even look like it is physically large enough to get a volumetric rate of flow of gasoline sufficient to produce 10KW, even at 100% efficiency. Relying on this “wave compression” idea should also severely limit the RPM range of the engine, since if it spins too fast the compression wave won’t have sufficient time to travel through the combustion chamber. Also, if it produced any amount of power, how exactly are they going to manage heat without a cooling system?

    It seems like it could work, but it would produce so little power that it would only be good for the POS econoboxes that we’re going to be driving soon.
    Even his claim of 25 KW would be enough to sustain a top speed of… 50 mph? 45 mph?

  • avatar
    Jeff Puthuff

    I think it’s designed to operate over a very narrow RPM range. It’s for electricity generation so the constant rate would not be a drawback. It might work very well in a series hybrid if the problems with cooling, materials strength, and scavenging are solved.

  • avatar
    twonius

    I think before we can critique this we’d have to do some reading

    http://www.egr.msu.edu/mueller/NMReferences/AkbariNalimMueller_JGTP2006_aReviewOfWaveRotorTechnologyAndApplications.pdf

    I suggest a pot of coffee and some scratch paper.

  • avatar
    PeteMoran

    Two words; Stirling Engine.

    Good advice twonius. I got mine.

  • avatar

    Just another university professor trying to get tenure by dipping into the feedbag of government grants for hairbrained “new” engine designs.

  • avatar
    John

    No way. Turbine, Rotary, Orbital, Stirling, Scuderi. I’m sure I’ve missed a few. With the exception of the rotary none have, or will ever make it. And the rotary only made it in a very small niche thanks to Mazda. Gotta hand it to Otto and Diesel. Thanks to continuous improvements they are still going strong.

  • avatar
    zerofoo

    An SUV with 25 KW? It’s been a while since my engineering classes, but that seems to be around 34 HP.

    34 HP seems too little to move around a modern SUV with all the safety equipment needed to make it roadworthy.

    Getting a 4500 pound SUV up a hill with this thing will be a challenge and you can forget about towing.

    -ted

  • avatar
    Martin Schwoerer

    The application Müller seems to be talking about is a range-extender for a series hybrid. As I wrote in my article about range extenders, what you’re looking for is compact size, light weight, low cost, low NVH, and acceptable fuel consumption at the engine’s RPM sweet spot.

    From a layman’s point of view, the Wave Disc engine looks promising on all accounts except cost. When you’re developing a totally new kind of engine for a given application, you have enormous development costs that need to be allocated to an unknown amount of produced units.

    On the other hand, if you can just adapt an Otto cycle engine, or a turbine, or a Wankel, most of the development work has been done (and paid for) by other people.

    Oh and by the way, somebody of no consequence whatsoever thinks that global warming is a crock of shit.

  • avatar
    MBella

    zerofoo: “Getting a 4500 pound SUV up a hill with this thing will be a challenge and you can forget about towing”

    The idea is for a series hybrid like the volt. It would use the motors to get up the hill.

    Am i still skeptical at 25KW? Yes

  • avatar
    Richard Chen

    @Martin Schwoerer: Hmmm, Fisker will be charging boatloads for his series hybrids, and has DOE funds to boot

  • avatar
    GS650G

    Why not just make those carbs that get 100 mpg? Or those air filters that give you 29% more power and mileage?

  • avatar
    Dynamic88

    The prof got a DOE grant of 2.5M

    http://stimulusfunding.msu.edu/approved-grants/detail.asp?EntryID=73&RecPos=1

  • avatar
    Pig_Iron

    Reminds me of Richard Clem’s engine.

  • avatar
    folkdancer

    the POS econoboxes that we’re going to be driving soon.

    Why do you hate engineers?

    Designing a good small package is more difficult than having huge size and power to work with.

    I like efficiency. How much can we do with how little.

    Designing small packages seems to be a lot of fun. Look at pictures from the Tokyo Auto Show.

    You might also want to read the history of the Spanish Armada when they attacked England.

  • avatar
    chuckR

    Every now and then, I check back on this company

    http://www.mechanology.com

    which holds patents on a compact high efficiency compressor/expander design. They have been working on this for more than a decade and a half that I know of. It is a struggle to move a novel technology forward which is competing with mature proven technologies where, as Martin pointed out, development costs are sunk, while you own all of yours. While your design may ultimately be of higher efficiency (while your demo unit may not be), its a tough sell.

    Sooner rather than later, the dollar will significantly devalue and buy less energy. In the US, higher efficiency will appear more cost effective and encourage more R&D and development like these efforts.

    Is the wave disc investigation worth $2.5mm in grants? If all they do is come up with a process improvement in thermal or acoustic control, tribology/sealing, better materials, yes. And you can’t determine that ahead of time. There is a lot of gov’t money wasted, but start by looking at earmarks that politicians like Murtha and Byrd specialize in.

  • avatar
    John Horner

    You can read a bit more about this project here:

    http://www.greencarcongress.com/2009/10/michigan-state-university-receives-25m-arpae-award-to-build-wave-disc-enginegenerator-for-series-hyb.html

    I have no idea if it is going to work or not. But, this investigation is the sort of thing University labs should be doing. $2.5 million to move this thing forward a step makes sense to me.

  • avatar
    chuckR

    Although ARPA-E is not (D)ARPA, let’s remember that the Internet we all like so much started out as ARPANet….. Government money well spent or not?

  • avatar
    Daanii2

    I have no idea if it is going to work or not. But, this investigation is the sort of thing University labs should be doing. $2.5 million to move this thing forward a step makes sense to me.

    I agree with that comment 100%. I don’t think this particular technology is going to work. It’s still (as near as I can tell) a heat engine, and thus subject to the second law of thermodynamics and less efficient than the Carnot cycle. I think ceramic engine blocks and free-piston engines have more promise.

    But this is legitimate research. The Department of Energy is pissing away $25 billion to give companies like Fisker, Tesla and the Big Three operating capital. They think that is going to advance the state of the art. What a waste of money.

    Much more likely that this project, and others like it, will change the way the world moves. Pennies spent on research will deliver more than dollars spent to fund operating expenses.

  • avatar
    Darth Lefty

    Yes it’s a heat engine. But if you acknowledge that a piston engine loses a ton of energy running the valve train, another ton running such low compression, another ton needing a transmission, and another ton operating most of the time far away from its best SFC, there’s a lot of potential for improvement.

    Even hooking a gas engine straight up to his generator to run a series hybrid would be a big improvement over lugging around a 200hp engine and a six-speed.

  • avatar
    Daanii2

    there’s a lot of potential for improvement

    True. A gallon of gasoline contains about 33 kilowatt hours of energy. The Lotus Elise gets about 25 miles per gallon. That’s about 0.75 miles per kilowatt hour.

    The Tesla Roadster goes over 3 miles per kilowatt hour. That’s about 4 times more efficient. Seems like a lot of low-hanging efficiency fruit for us to pick.

    But it’s not as easy as it seems. People have built series hybrids, and found that the seemingly easy gains disappear. The Chevy Volt, for example, does not do as well as many of us expected on gasoline alone.

    Still, I think you’re right that there are efficiency gains out there. Good to see Norbert at Michigan State trying to get them.

  • avatar
    Martin Schwoerer

    Daanii, please keep in mind that nobody is proposing a series hybrid that runs on gas all the time. The normal case would be electric for the 90% of the rides that are less than 50 miles. The engine only kicks in when you want to visit Grandma. How important is the fuel economy you get on 10% of your rides, when the rest of the time you get zero emission transport for peanuts?

  • avatar
    pariah

    I hate it when people say things like, “five times less.” Five times less would be a negative number! So what do people mean when they say that? One fifth?

  • avatar
    fincar1

    …and when people say things like “zero emission transport” re electric-powered vehicles you know they don’t live anywhere near a fossil-fuel power plant.

  • avatar
    Fritz

    If this device is able to translate the actual shock wave of combustion into something other than noise and heat isn’t that nearly a pure gain over a conventional engine in this respect? Would the exhaust from the wave disk engine drive a turbo to compress air for its intake?

    I’d love to see a diagram of whole working device and not just the part Mr. Mueller is holding in his hands.

  • avatar
    Greg Locock

    It’s a bit like the comprex type of turbocharger. Sadly credibility wains when the linked article claims 5 times more efficient than an auto engine – a Prius operates at better than 30% all the time except when idling.

  • avatar
    PeteMoran

    What the good Professor says (I think) is you can go 3.5 times further than a “regular” hybrid vehicle or 5 times further than an otherwise normal SUV (which I guess means hybridising the SUV first, then the 3.5x rule applies).

    In other words;

    20MPG turns into 100MPG.

    Anyway you look at it, that’s a very big claim.

  • avatar
    udham

    True. A gallon of gasoline contains about 33 kilowatt hours of energy. The Lotus Elise gets about 25 miles per gallon. That’s about 0.75 miles per kilowatt hour.

    The Tesla Roadster goes over 3 miles per kilowatt hour. That’s about 4 times more efficient. Seems like a lot of low-hanging efficiency fruit for us to pick.

    The problem with this analysis is – how do you define efficiency? Something like the Telsa Roadster moves the Carnot efficiency hit upstream. Assuming that the efficiency of the coal plant combined with the efficiency of the grid is 50% (sounds reasonable), the efficiency multiplier of the Tesla just dropped to 2 instead of 4. Driven conservatively, the elise can hit 30+ mpg on the highway. That makes the efficiency gain of the Tesla even smaller.

    Obviously if the upstream plant is nuclear/wind/solar, then from a carbon standpoint, the Tesla is much much better. Wind/Solar with the current state of the art will not be able to generate the energy the world requires. Nuclear suffers from a serious case of NIMBY.

  • avatar
    PeteMoran

    @ udham

    In my day-to-day work on and around energy projects we normally work with the “local” efficiency. It’s an extremely complex task otherwise. People attempt it in the form of “Carbon Accounting”, but that’s a controversial subject (for some).

    In your rebuttal of the Tesla example, you could also make the same argument about MPG not taking into account the upstream energy costs of drilling, transporting and refining the fuel in a car. People don’t (can’t?) sit down to work that out.

    The only indicator as to what is going on, and it’s highly distorted for ALL forms of energy, is the price per unit.

  • avatar
    udham

    @PeteMoran

    I appreciate your response.

    I am not sure if my response was a “rebuttal” of sort. I was just trying to point out that there is more to what meets the eye as far as “efficiency” goes and that qualitative blanket statements are almost bound to be off.

    I agree that with oil, there is probably a relatively big added carbon cost of converting dino juice into the ground into something you can put into your tank. Of course, for coal/natural gas/oil fired plants, there is an added carbon cost of getting the carbon out of the ground and getting it to the power plant.

    So you are right, people are not going to want to figure out the intricacies of where their energy comes from, and exactly what their carbon footprint is. Maybe regulation is the answer, or maybe regulation leads to controversial and in my opinion asinine decisions like corn based ethanol being added to fuel.

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