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Thread: Rotary diesel?

  1. #16
    Registered User Turner's Avatar
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    Re: Rotary diesel?

    As was already mentioned, Wankel Supertec and Wankel AG (both in Germany) are running a joint venture in a new line of diesel rotaries. It looks promising with plans for a range of engines of 1 up to 4 rotors, with 500 cc per rotor. They say they can get 65 hp per rotor which sounds reasonable.

    I'm following their development with great interest.
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  2. #17
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    Re: Rotary diesel?

    What about the Renesis with its High Tech intake and fuel delivery system........how would that work running on desiel....maybe not a compression run desiel, but running on that fuel (or JET A)

  3. #18
    Registered User Wesleyvi's Avatar
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    Re: Rotary diesel?

    The engine you are talking about was the Newbold Rotary Diesel Engine. Vern Nerbold is still working hard on this engine.

  4. #19
    Registered User dino's Avatar
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    Re: Rotary diesel?

    Zoche diesel radials are alive but not running. They exhibited at Aero 2012 last week. They have pursued design, patenting and prototyping but have stopped there most likely intentionally as it a more viable to develope using EU grants than it is to manufacture.


    Dino

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    Re: Rotary diesel?

    Hi
    The rand cam enginehttp://www.regtech.com/Radmax_Technology/

  6. #21
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    Re: Rotary diesel?

    http://www.regtech.com/Radmax_Technology/

    $0.10 per share and an average 3 month trading volume of only 3,213! Unless they have found a way to keep the vanes from wearing/breaking this looks like another penny stock scam to me.
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  7. #22
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    Re: Rotary diesel?

    Quote Originally Posted by JCP View Post
    No, just business, just a matter of money flow...


    JCP
    Correct, you would be surprised at how much money "the Big Bad Three" (along with the others) throw at patents and licences every year but nearly always at the end of the day there is no profitable way forward for those ideas. Usually the patents and licences are purchased in order to see if the idea can be developed, not quashed by the MIB.


    Quote Originally Posted by JCP View Post

    Anti-Wear Coatings, Heat Rejection Coatings, and Seals have all improved. Perhaps it is time to revisit a Wankel-Diesel !

    JCP
    Nope, simple case of the thin crescent shaped combustion chamber offering far too much surface area soaking up too much heat in a rotary to be successful as an efficient diesel. Check out the Rolls Royce diesel wankel to get an idea of whats required to get the combustion heat, suddenly all thr rotary's advantages just went out the window (along with the apex seals :-)).

  8. #23
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    Re: Rotary diesel?

    When we built working models of new design dieseling engines there was a lot of fuel mixing to get them to run ..
    we had spark plug.. glow plug.. air injectors.. and fuel injectors all in the same head..
    My point is the many variables that can be tested..
    I personally do not think a Wankel engine can run well as a diesel..

  9. #24
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    Re: Rotary diesel?

    Hello everyone,Im new don't own a plain or have the means to,my speeling is bad and grammor worce, but I own and have been driving a almost 100% diesel powered rotary rx8 and need some advice on eliminating spark. I have some ideas and I think the renesis solves many of the prior problems discussed above with two cooling jackets more ports and higher revs. Now torque I belive is an issue between us am I right, please anything possitive would be greatly welcomed as support is lean at best here at home.

  10. #25
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    Re: Rotary diesel?

    Rotarywheelmen, I am building a four rotor with my own aluminum end housings of 398 aluminum (17% silicon carbide alloy) and in anticipation of possibly running on diesel I have included mounting bosses for direct injection thru the side housings. Getting fuel sprayed in is the first step. The second is the mindset of the rotary RPM. The balance point where gas pressures and centrifical force are
    equal is 6200 RPM on the stock Mazda RX8 and would be higher on a diesel. I remember the RC aircraft diesels which had adjustable compression. Turn it in to start and as it heated up screw it out for less compression and more speed. With more RPM there is less time for heat loss thru the side housings and rotor. In a post above it was suggested that the large surface area of the moving combustuion chamber would transmit too much heat away making it difficult to ignite diesel fuel. I disagree with this notion by intuitionn alone. A four stroke diesel has 1 hot power stroke with 3 strokes to cary heat to the water jacket.The Wankel engine has the exhaust and intake strokes occuring while the other rotor faces are fireing. Also on a piston diesel the cylinder wall adds considerable surface area and is water cooled.One third of the Mazda heat rejection is thru the oil cooled rotor which has a lower transfer rate than water cooling. Second point is that the 8 pound rotor is what limits the RPM on the Mazda engine. If I get serious about running on diesel I would carve ceramic rotors on my CNC machine which would transmit almost no heat. Think of the ceramic tiles the space shuttles were covered with.....machined ceramic blocks. For several years pistons have been used on road tractor diesels which have ceramic tops so the temperature and shock of the diesel fireing would not seem to be an issue. I am waiting for Ford and Mazda to make available in the US their laser ignition as used on the Mazda 16B and some sky-active engines but not available in the US at present. The DD15 diesels have a turbocompounding setup which is geared to the crankshaft for starting boost and as the exhaust gets flowing to spin the turbo, excess power is sent back to the crankshaft recovering 8% power from the waste heat as useable torque. There is a double expansion Wankel (rotors in series) which recovers exhaust residual power on one face with the other side of the housing supercharging the first stage rotor. I think it is a marine engine, ciurrently lost on 11.5 terabite of hard drive of this computer.
    When you say you drive an almost 100% diesel rotary would that mean a mix of diesel and 87 octyane gas with spark ignition? My misspelling is due to an enthusiastic keyboard that likes to add a b or d or change to caps just to make things interesting.
    wizzardworks

  11. #26
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    Re: Rotary diesel?

    Quote Originally Posted by Reg LeBlanc View Post
    Hi All: I'm not sure if this is the right place to ask but,does anyone have any information on a rotary engine that will run on diesel fuel. I have been told that there was something at Oshkosh a while back. I haven't been able to find any info on who it was or what the details of the engine were. Regards...........Reg
    The Britich developed a very nice diesel rotary using a large displacement rotary as the compressor and a smaller as the diesel engine. Much too heavy for aircraft use. But serviceable for stationary power. Lynn E. Hanover

  12. #27
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    Re: Rotary diesel?

    Quote Originally Posted by wizzardworks View Post
    In a post above it was suggested that the large surface area of the moving combustuion chamber would transmit too much heat away making it difficult to ignite diesel fuel. I disagree with this notion by intuitionn alone.
    Disagree all you want but you are technically and historically 100% wrong, surface area and combustion shape is just one of many big issue with rotarys and that's why there are no diesel rotarys. There are other very major issues as well, enough that no one makes one and unless some technology dramatically changes, never will..


    Quote Originally Posted by wizzardworks View Post
    A four stroke diesel has 1 hot power stroke with 3 strokes to carry heat to the water jacket. The Wankel engine has the exhaust and intake strokes occuring while the other rotor faces are fireing.
    Also on a piston diesel the cylinder wall adds considerable surface area and is water cooled.One third of the Mazda heat rejection is thru the oil cooled rotor which has a lower transfer rate than water cooling.
    A piston engine is by far more efficient than a Wankel is, it provides energy to drive the piston far more effectively per charge than that of a rotary's partly due to it's by far smaller internal surface area than the rotary's.

    FWIW, a 2 cylinder, 4 cycle piston engine is equivelent to a rotary in terms of 1 firing pulse per 360 degree crankshaft rotation or a single cylinder 2 stroke.

    While a rotary has packaging advantages of a "3 in 1 piston" (loosely speaking), that very packaging causes many of it's main disadvantages but no need to explain that to a guy building a 4 rotor wankel of course.
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  13. #28
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    Re: Rotary diesel?

    NASA did one like this back in the late 70's or early 80's I think. Glow plug in the trailing spark plug hole, high pressure injector in the leading spark plug hole, turbos bolted to the intake manifold - no throttle plate - more fuel = more power. I've been looking at the NASA archives for a tech note or documentation so far no luck. I think seals may be an issue at the high compression ratios. The concept still fascinates me. I'll keep looking. It would also seem there must be some fundamental flaw since it hasn't been done yet and it looks such an obvious thing to do.


    Quote Originally Posted by JCP View Post
    The German company "WankelSuperTEC" appeared to have an approach to a Wankel-Diesel that looked very promising.

    Direct Injection with a Spark plug to get it started.

    Once Turbo spooled up under load, would run as a Diesel.

    Turbo boost (2:1 to 3:1) plus Wankel compression (8:1 to 9:1)
    got you into normal Diesel compression ratios.

    No Intercooler, hot compressed air out from Turbo further compressed and heated by Wankel compression cycle to diesel ignition temperatures.

    Hence 2 stage compression, and 2 stage expansion.

    At light load (i.e., low boost) I've heard that it needed spark to run smoothly. (or a glow plug)

    Project either ran out of money or went black and may now be powering drones.

    JCP

  14. #29
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    Re: Rotary diesel?

    The C-W, John Deere, Rotary Power International SCORE 580 engine was a diesel direct injected Wankel Rotary engine.
    It was intended to have a high power to weight ratio for use in battle tanks.
    It lost funding during the military cut backs of the Clinton Administration.
    Here is a link to a discussion of the slow painful death:
    Rotary Power International? - RotaryNews.com
    The Mazda 13b type engine might be the 70 series engine mentioned in the link, one smokey example being built.

  15. #30
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    Re: Rotary diesel?

    What is the problem with having spark plugs on a rotary diesel? Seems like a small compromise and could improve BSFC. In its normal configuration the heat of compression
    raises the air temp above the flash over point of the fuel and the fuel ignites as it is injected. This makes the fuel injection timing an important issue where with spark
    ignition the fuel and air could be mixed during the compressdion stroke. The spark would then start a conventional flame front heating the mixture as it propigates. A
    turbocharger seems like an excellent choice on an aircraft engine but I was thinking the exhaust heat could be used like a cabin heat muff on the diesel intake to
    preheat the air so that less comression is needed to get the air above the flashover point. This seems more effective than heat transfer from the cylinder wall and
    head which are water cooled to a surface temp below 400 degrees F. I am also not convinced by the argument that a wankel combustion chamber particulary one
    smaller to raise compression is relevent. Some diesel engines like Internationl Harvestor had a prechamber in the head to start a flame front but the majority don't
    have anything but a flat space between the piston top and head. Personally I don't have a problem with starting a wankel diesel with a separate injector that
    injects gasoline to get up to temperature. No different than a modern 2 stroke having an oil injection pump to avoid premixing fuel and oil. The real goal is the
    ability to burn jet fuel or kerocine in parts of the world where gasoline is extremeny expensive or unavailable because engines run on soy bean oil.
    wizzardworks

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