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Complicated little buggers though?
There are quite a few "older" designs for two stroke engines that never really caught on: Stepped piston two stroke[^]
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No, not complicated at all really. They have no valve train, and are more thermally efficient. They have a blower to help scavenge, but most diesels have a turbo anyway. They are simpler than todays engines.
The steped piston isnt different from the crank case scavenged tqo stoke which is simpler and widely used today.
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It's very different! It uses a 4 stroke-like lubrication system (which means the lubricant isn't total loss with the emission problems that gives "normal" 2 strokes) and the ratio of the two piston's swept volumes can be adjusted to increase or decrease the "supercharger" effect.
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Interesting.
I would have thought the following were a problem in cars/trucks:
Rapid heating and cooling: It's going to alter (weaken?) the engine block. Might temper it in such a way it improves, not thsat much of an engineer.
Steam: These things must puff out steam like billy-o. Or they would need condensers.
Water: Obviously, if you have a condenser you can recycle, but I'd assume this would end up with warm water being injected. I think this would reduce the power gain, naturally it would reduce cooling. :/
Seems like sensible arrangement though, especially as the cost of fuel rises. Must be more complex & expensive to manufacture.
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Check out the 6 stroke engine, there are some vids on line, they are incredible. So sinple, so efficient.
Of course you need a water tank as well as a fuel tank. The gasses are natural, but yes, they will steam a bit.
The main thing is it gets rid of the radiator, hopses, water pump etc etc etc. A smaller, tidier engine even with the addition of the water pump and additional injectors.
It will happen. You wait.
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When I was child we used to have a Trabant[^], which had a two-stroke engine...
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is (V).
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When I was a fully grown adult, capable of making a rational decision I bought a Trabi. Why? Because they rock! For getting around town they where ideal and they really annoyed the green lobby; which was nice.
speramus in juniperus
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The common between these two, that both made of pressed paper painted with colored varnish...
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is (V).
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Nope. Yugos are ex Fiats, 127s and 128s to be precise.
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Yes. But remade of paper.
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is (V).
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I think they are but the fact that you need to get the rebuilt after 50K-60K miles makes the idea of the Wankel a poor engine.
Someone I work with just had his RX8 engine rebuilt to the tune of £2500 pounds.
Every day, thousands of innocent plants are killed by vegetarians.
Help end the violence EAT BACON
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Must resist urge to make puerile joke about the name "Wankel"... 
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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But inefficient, not ecconomical and dont produce much torque.
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Ok but:
less moving parts == less moving mass
less parts == lighter engine
It might consume more but revs up much faster than a piston engine.
Also, the time invested improving this type of engines is nothing compared to the time invested in piston engines.
No further developments make sense now as we moved on to new techs but still it's an ingenious peace of mechanics 
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Ahh! Happy days! I got my tracked vehicle licence driving a very large, very heavy tin box, powered by a Rolls Royce K60 multi-fuel. Mind you, if you used the wrong oil in the fuel type control, then the seal would perish, the plunger drop, and the engine go to full throttle. I once saw one of these tin boxes drive straight through the side of a German farm house... 
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Actually the hotel I am in in Germany got hit by a car. It bust one of the main wodden uprights and pushed it and the wall into reception.
I dont thihnk it would be hard to go straight through if you had some welly behind it!
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Ah, memories... Never worked with them but did do a short course in college that covered the topic. Mind you, that was so long ago that I would not have recalled the subject without that article to prompt me.
I think it may be too little too late for these marvelous little pieces of engineering: I foresee efficient electrically powered vehicles becoming the norm in the next 10 or so years, consigning all of the other engines to history and vintage/antique collectibles.
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur." Red Adair.
Those who seek perfection will only find imperfection
nils illegitimus carborundum
me, me, me
me, in pictures
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Did you have a background in mechanical engineering too Mark?
I still love it, more than software, but the pay is bad, jobs non existant, and you cant travel the world doing it. but my real passion is still for machines..
Anyway, back to the fuel. Electric is interesting, but its all about energy density; electric just doesnt deliver compared to other fuels. And particularly with the kind of technology I linked to, in addition to water injection to use the extra thermal energy, will give efficiency and smoothness way beyond todays diesels.
Imagine an engine that can do 7 k rpm, is smooth as silk and gives 50 mpg at 100 mph. Thats the kind of diesel that could be done with this technology. I really cant see why we stick with the classic 4 pot valve scavenged system.
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Erudite_Eric wrote: Did you have a background in mechanical engineering too Mark?
Yup: spent years working with Jaguar and Lotus amongst others. Miss it, really. Nothing quite like building an engine and then turning the key for the first time.
Or restoring an old car. Like a 1932 Merecedes or an amphi-car or a head-to-tail rebuild of an E-Type or rewiring a burnt out Jensen Interceptor (that was cool because the factory used to buy looms from different suppliers so the wire color was never consistent. Fun.
Anyways, it's only a matter of time until electric vehicles become feasible; apart from anything else, it's what the public think they want.
Oh, the reason we stick with those engines is because of the noise.
Oh, don't ask me now how to fix anything: that's what the AAA is for!
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur." Red Adair.
Those who seek perfection will only find imperfection
nils illegitimus carborundum
me, me, me
me, in pictures
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The "Omega" was very promising, but manufacturing (machining) was a bitch!
Dave.
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