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posted by Dopefish on Friday February 28 2014, @10:00AM   Printer-friendly
from the rev-up-and-burn-out dept.

germanbird writes: "Jalopnik has an interesting article up about Koenigsegg's Prototype Camless Engine. The engine uses pneumatic actuators rather than a cam to open and close the valves in the engine. The engineers behind this claim that it can provide "30 percent more power and torque, and up to 50 percent better economy" when applied to an existing engine designs. The article and some of the comments also mention that some work has been done with electromagnetic actuators to accomplish the same task. It may be a while before this tech is mature enough for passenger vehicles, but maybe if a racing series or two picked it up, it might give some of the manufacturers the opportunity to work the bugs out?

Not sure this is on topic for SoylentNews, but the article brought me back to my introduction to engineering course in college. One of my classmates was a car nut and I remember a discussion with an EE professor one day about the potential (or actually lack thereof due to performance issues) for using electric actuators to open and close valves."

 
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  • (Score: 5, Informative) by ls671 on Friday February 28 2014, @10:25AM

    by ls671 (891) Subscriber Badge on Friday February 28 2014, @10:25AM (#8401) Homepage

    Somebody already got away with camshafts and even crankshafts a while ago. Pretty efficient too.

    https://en.wikipedia.org/wiki/Wankel_engine [wikipedia.org]

    https://www.youtube.com/watch?v=6BCgl2uumlI [youtube.com]

    https://en.wikipedia.org/wiki/Mazda_Wankel_engine [wikipedia.org]

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  • (Score: 3, Informative) by carburraetor on Friday February 28 2014, @10:43AM

    by carburraetor (2221) on Friday February 28 2014, @10:43AM (#8406) Homepage

    Two stroke engines dont use camshafts as well, they use ports http://en.wikipedia.org/wiki/Two-stroke_engine [wikipedia.org]

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    • (Score: 5, Interesting) by c0lo on Friday February 28 2014, @11:14AM

      by c0lo (156) Subscriber Badge on Friday February 28 2014, @11:14AM (#8417) Journal

      And again, there was [wikipedia.org] and now is this one [wikipedia.org]

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    • (Score: 2) by c0lo on Friday February 28 2014, @11:51AM

      by c0lo (156) Subscriber Badge on Friday February 28 2014, @11:51AM (#8430) Journal

      Here's a clip of how 1962-64 Chrysler Turbine Car sound [youtube.com] like (around 2'45" you can see it being driven)

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    • (Score: 1) by cwix on Friday February 28 2014, @01:02PM

      by cwix (873) on Friday February 28 2014, @01:02PM (#8456)

      Yes, but two strokes are notoriously inefficient, and polluting. You loose some of your fuel on the compression stroke.

      • (Score: 2) by Foobar Bazbot on Friday February 28 2014, @09:56PM

        by Foobar Bazbot (37) on Friday February 28 2014, @09:56PM (#8822) Journal

        Two-stroke gas engines have those problems. But two-stroke diesels are very nifty -- a blower provides scavenging without crankcase involvement, and not injecting the fuel till you're ready for combustion means none gets wasted. (Most do have a camshaft and exhaust valve(s) for uniflow scavenging, but cross-flow scavenging is also possible.)

        • (Score: 1) by cwix on Friday February 28 2014, @11:23PM

          by cwix (873) on Friday February 28 2014, @11:23PM (#8879)

          Good point. I am actually not that familiar with two stroke diesels. I'm not even sure what the use case is for them. I will have to do some reading. Thanks!

    • (Score: 2) by Grishnakh on Friday February 28 2014, @04:19PM

      by Grishnakh (2831) on Friday February 28 2014, @04:19PM (#8570)

      Two-stoke engines are horrifically polluting and fuel-inefficient. They have very high power-to-weight ratios, however, and are mechanically simple, which is why they're frequently used for portable lawn equipment (weedwackers, leaf blowers, chainsaws, etc.). However, they've been banned from some municipalities because of the pollution, and 2-stroke boat motors have been banned from many places for the same reason.

  • (Score: 3, Interesting) by tirefire on Friday February 28 2014, @10:54AM

    by tirefire (3414) on Friday February 28 2014, @10:54AM (#8410)
    As I understand it, Wankel (Rotary) engines have had trouble meeting emissions requirements, prompting Mazda to discontinue the RX-8 recently.

    Still a very cool design, and it's a shame that Mazda seems to be the only company interested in it. I've never had the pleasure of driving an RX-7/8, but I've heard that unlike reciprocating piston designs, their rotaries run smoother the faster you rev them (downside: a rough idle).
    • (Score: 2) by Grishnakh on Friday February 28 2014, @04:26PM

      by Grishnakh (2831) on Friday February 28 2014, @04:26PM (#8574)

      Yep, and they also were notorious for having crappy fuel economy for the power they produced.

  • (Score: 4, Funny) by Vanderhoth on Friday February 28 2014, @12:43PM

    by Vanderhoth (61) on Friday February 28 2014, @12:43PM (#8448)

    You guys are totally ruining my day, I just spent two hours watching engine videos and now have two less hours to finish my stupid SOP and test case documents. Totally worth it.

    Thanks, jerks.

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    • (Score: 1) by monster on Friday February 28 2014, @04:41PM

      by monster (1260) on Friday February 28 2014, @04:41PM (#8582) Journal

      Hey, at least there wasn't a link to tvtropes... In that case it would be game over!

  • (Score: 1) by epitaxial on Friday February 28 2014, @01:38PM

    by epitaxial (3165) on Friday February 28 2014, @01:38PM (#8477)

    You do know that rotary engines need a teardown and rebuild much much sooner than piston engines? Fun fact: if you own an RX-8 they recommend you check your oil level every 3 gas fill ups. The engine burns that much oil.

    • (Score: 1) by Kromagv0 on Friday February 28 2014, @02:32PM

      by Kromagv0 (1825) on Friday February 28 2014, @02:32PM (#8509) Homepage

      Well that was suppose to have been fixed with the RX-8 generation of rotary engine but they still couldn't resolve the problem with the carbon tips of the rotors lasting. This was a problem on the old RX-7 rotaries as well. It is an interesting design but it just never seems to deliver.

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      • (Score: 1) by computersareevil on Sunday March 02 2014, @02:11AM

        by computersareevil (749) on Sunday March 02 2014, @02:11AM (#9345)

        Fact 3: No RX has had "carbon tips" aka apex seals since the early 1970's. The have been a steel alloy since at least the RX-3 introduced in 1972. They still use carbon apex seals in some VERY high-power applications, and yes, they don't last long. They've mostly been supplanted by ceramic apex seals.

        Fact 4: The RX-8 engine doesn't die due to apex seal failure. The most common failure appears to be rotor side seal failure caused by excess carbon buildup in the side exhaust ports, which is caused by not revving the shit out of the engine daily. The RENESIS engine is the first Mazda rotary with side exhaust ports instead of peripheral ports.

        Fact 5: The RX-7 never had a problem with apex seals. Normally-aspirated RX-7s routinely go hundreds of thousands of miles without problems (so long as they are properly-driven). The third-generation FD RX-7 didn't have problems with apex seals, it had problems with boost and fuel control. A cluster-fuck of vacuum hoses and solenoids controlled the sophisticated sequential twin-turbochargers. The cluster-fuck would spit a hose periodically, which would cause a sudden lean condition under boost, leading to catastrophic detonation and subsequently popping an apex seal. The apex seals are not the cause any more than a burned valve or punctured piston is the problem in a boosted piston engine that goes lean. Securing the cluster-fuck of hose ends to their fittings with cable ties solves that reliability problem.

        In summary, pretty much all the reputation problems with the Mazda rotary engines amount to FUD, which makes it all the more painful to read it being spread by (supposedly) fellow geeks on SN.
         

    • (Score: 1) by computersareevil on Sunday March 02 2014, @01:53AM

      by computersareevil (749) on Sunday March 02 2014, @01:53AM (#9337)

      Wrong. I own a road-race-track-driven 2005 RX-8 with 70k miles on it, no rebuild yet. Many are over 100,000 miles without a rebuild.

      What happens to the Mazda rotaries that shortens their life is that ignorant people like you don't read the owner's manual or look up basic facts about the engine, abuse and neglect it, then bitch when it dies on them.

      Fact 1: "Oh, it burns the oils!" The Mazda rotary burns oil on-purpose. This is how it lubricates the apex seals. This is how it's been since the Mazda Cosmo Sport 110S [wikipedia.org] was introduced in 1967. And yet here we are 46 years later and people still can't get it through their soft skulls that it burns oil on-purpose.

      Fact 2: Properly maintained and driven Mazda rotaries will go hundreds of thousands of miles. I also race a 1985 Spec RX-7 with 167,000 miles on the engine. They aren't really "broken-in" until they are over 100,000 miles. The secret is that if you drive it like a piston engine, you will ruin it. Everything in a rotary should be done at least 2X the RPM of a piston engine. It should be redlined at least daily, if not at every shift pulling away from a stop. That doesn't mean drag race it at every light, it just means don't shift until the little buzzer lets you know that 9000 RPM has arrived and you should shift when you get around to it. The buzzer is the only way you'll know this buttery-smooth little engine is turning that fast. People who regularly drive under 2000 RPM and never shift over 6000 will kill the engine in under 50k miles.

  • (Score: 1) by Kromagv0 on Friday February 28 2014, @02:38PM

    by Kromagv0 (1825) on Friday February 28 2014, @02:38PM (#8512) Homepage

    The best thing the rotary engine has going for it is the higher specific output since it is much closer to a 2 stroke than a 4 stroke otto cycle engine. There was suppose to be some wonderful efficiency gains since there were so few moving parts but they typically have been over stated. Also add in the wear and premature failure of the carbon tips that has plagued Wankels from the beginning and it is a niche product. They are a nifty little engine none the less and I applaud Mazda for trying to perfect them.

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  • (Score: 3, Interesting) by frojack on Friday February 28 2014, @07:45PM

    by frojack (1554) on Friday February 28 2014, @07:45PM (#8723) Journal

    Come on guys, a subject of hmmmm just makes you look dumb. Don't type like you talk.

    Wankel was a good try, but it still wasted a lot of energy, and emitted too much un-burned gas.

    The problem was getting the porting just right wasn't feasible other than for a very limited range of RPM.

    Frankly, this new air-operated system seems interesting, but the use of air is imprecise, and inefficient. Air is compressible, and about 30 percent of the power applied to air actuators (of just about any sort) goes to just compressing the air to working pressure. Then you have to vent that built up pressure when you want the valve to close again.

    Hydraulic would seem much faster, and more precise way of moving the valve stem. Electric valving of the Hydraulic fluid would allow computer controlled adjustment for timing. Hydraulic chambers for both Raise and Lower could eliminate valve springs as well, meaning the engine wouldn't be wasting energy compressing a spring.

    (Note: Hydraulic lifters as used today are simply a buffer between cam shafts and valve stems, so not the same thing).

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