How about a little Encyclopedia Hoonatica to make your hump day a little less humpy? It’s funny how one thing leads to another, and from where inspiration arises. A couple of days ago I was listening to the radio, and a story came on about a man who needed a new heart valve. Once the stuff of science fiction, prosthetic cardiac valves are now commonplace, and thousands of people go about their daily lives with one ka-thumping in their chests. All that amazing medical advancement got me to thinking about the valves that are almost as important as the ones in Cupid’s target, meaning the valves that allow the traditional ICE to work. But what if that engine, wasn’t so traditional?
The original poppet valve predates the internal combustion engine, having been used in steam engines and pumps for years prior – and in fact the Presta or Schrader valves on your tires are examples of them. The earliest forms of reciprocating ICEs were just as likely to have slide valves, but as compression ratios and engine speeds increased, the simplicity and effective nature of the coil-sprung poppet became a standard form of gas flow management in vehicle applications. F-heads, L-heads, and OHV engines, there have been plenty of applications of that traditional poppet with coil spring over the years, and of course the form remains the standard fitment to this day in most of the cars, trucks and motorcycles on the road.
Except for those which don’t. Today, we’re cataloging the automotive, motorcycle and hell, even snowmobile, engines that eschew that traditional application of the coil on mushroom valve system for something a little more, shall we say, esoteric? I’ll start off with one that we all know – an easy one to get the juices flowing as it were – the desmodromic valve system. This mechanism utilizes mechanical opening and closing of the valve – so as to provide precise valve timing (before computer engine controls) and limit valve float – the condition when engine speed causes the valve’s ineria to overcome the spring’s ability to push it closed. Mercedes applied desmo heads to its 1954-55 W196 Formula One cars, and Italian motorcycle maker, Ducati has made it a feature of their wide-angle twins for more than 5 decades. The downsides of the Desmo system are additional frictional losses, weight, and maintenance- the last being either a frustration or a badge of honor among Duck owners.
There are other less-common valve systems in use today, and a lot that have come and gone – there have been other methods of valve return employed, including torsion bar and leaf spring, and of course there are a number of engines that shun the poppet altogether, and I’m sure we’ll see some examples of those here too. So, what say we get this party jump started, how many non-traditional valve system engines can you name?
Don’t forget the rules: Read the existing posts first, don’t post duplicates, and shrink your large photos to 500 pixels wide.
Image sources: [ducatimonster, two-stroke-engine.com]
Encyclopedia Hoonatica: Non-Traditional Valve Systems
43 responses to “Encyclopedia Hoonatica: Non-Traditional Valve Systems”
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How about the easy one:
Pneumatic valves used on F1 engines (among others)
<img src="http://www.pureluckdesign.com/ferrari/f1engine/valvesystem1.jpg" width="500"> -
Winton used air-controlled valves, which I suppose would be considered pneumatic.
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The Knight sleeve valve system used on several prewar cars http://en.wikipedia.org/wiki/Sleeve_valve
There were also rotary valve systems which had a drum or disc in the head http://www.aqpl43.dsl.pipex.com/MUSEUM/POWER/unus…
And lots of 2 strokes used a rotating disc on the crankshaft to control air intake.-
The Knight engines were unusual in that unlike conventional engines, some carbon buildup over time was actually a good thing in that it improved both the lubrication and sealing of the valve sleeves.
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Well, that's both of the things I was going to say.
I thought up disc valves some time ago before hearing this idea already existed. I'm still not convinced they aren't totally practical and awesome. -
Sleeve valves were also used on some British WW2 radial aircraft engines.
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FPT's Multiair is something of a hybrid, still using poppet valves directly activated by the cam in the case of the exhaust valves, but the intake valves are operated by the controlled release of a quantity of pressurized engine oil which is first pumped by another lobe on the cam.
<img src="http://www.fptpowertrain.com/ita/img_engines/Image-No-9_low.jpg" width="500"/>-
That was going to be my answer!
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If it's any consolation, the Aspin rotary valves are more obscure and less conventional. MultiAir is clever but there's no denying that half of the valvetrain is plain old SOHC cam-over-bucket.
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Valves? The small figure at the top shows a reed-valve two-stroke, but that's overkill. Really all you need is the piston moving up and down past some ports in the cylinder wall.
<img src="http://www.saabisti.fi/wp-content/uploads/2009/03/saab-96-engine-2.jpg" width="400">
Worked just fine for SAAB (shown) or, as far as that goes, KV. Your mileage may vary. Mine certainly does.-
I try to keep it to a minimum, so only when it's appropriate (or is that a maximum?). It does seem the car occupies a sweet spot for "Hooniverse Asks: What's a Stubbornly Contrarian Way to Accomplish X?" though. If Encyclopedia Hoonatica ever gets around to an entry on rack-and-chain steering or post-War mechanical brakes, it'll be there.
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Or tire friction drive.
– KV
– AMF Roadmaster
– Velosolex
– …????-
Quite a few mopeds. High on the list should be the Zanetti (aka Bicizeta), designed to come apart for ease of, um, transport? storage? use? Let's just say "for ease."
<img src="http://vroum52.com/vroumcyclo.img/Bicizeta-4%5B1%5D.jpg" width="300">
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Really all you need is the piston moving up and down past some ports in the cylinder wall.
Or the piston moving round and round past some ports in the cylinder wall.
<img src="http://i615.photobucket.com/albums/tt237/jskitter/hooniverse/mazda-rotary-engine.jpg" width="500">-
Yeah, but that's not a REAL engine. It just fills in for a while until the owner replaces enough valve seals that they pull the sucka out and replace it with a traditional SBC.
/puts on flame suit.-
Actually, SBF in my case. Aluminium heads will help with the weight difference.
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I found this simplified operating diagram of the RX-7 Turbo's 13B-REW that seems appropriate:
<img src="http://img33.imageshack.us/img33/6453/apexseals.gif">
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"Or the piston moving round and round past some ports in the cylinder wall."
I've had something like that happen in one of my SAABs, actually.
<img src="http://farm6.static.flickr.com/5251/5492274401_5eb36cfc4d.jpg" width="450">
The middle piston didn't leave the factory with a crinkle-cut perimeter; that developed during a few miles of freeway driving after the horrible noise started. [The car made it home, though!] Admittedly only a few bits of the piston were moving round and round past the ports, but that seemed to be enough.
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A piston-port 2-stroke still has valves…they just double as the piston skirts.
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Renault was rumored to be testing a variation of Siemens electromagnetic valve actuation in testing prior to the 2002 F1 season. I don't recall ever hearing that confirmed or disproved.
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It's so pretty!!
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That's because it runs on blue paint and expels red paint as a product of combustion.
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Rambler used an engine that could interchangeably use either an L-head or OHV design. When first introduced, the ubiquitous 195.6 inline-six used an L-head design, which basically meant that it worked the same as a conventional design, except that the valves opened upwards into an intake plenum, and the combustion chamber didn't completely seal in the "traditional" hemispherical design we think of now.
I can't find a picture of it, so I'll just post a photo of the engine that ate so many pieces of my fingers, and still earned my love.
<img src="http://www.allpar.com/images/1964/rambler-six.jpg" width="500"> -
I remember reading in 1998 or so how all cars were going to convert to 42 Volt electrical systems. this was going to be driven by the switch to solenoid operated valves.
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Yeah, we even updated a bunch of our systems in the Ford wind tunnels to be able to power/read the 42V systems…that never materialized.
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So, what happened to the 42V system? I thought it was supposed to be here by now, in our flying cars…
Seriously, I would enjoy an article on this subject by someone in the know.
My understanding is with 42V, the alternator and starter motors would be one and could even become a milde hybrid…
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I'm going for my 2 favorites, which are likely my 2 favorites because the info is not easily googleable.
Early stationary engines had atmospheric intake valves. Engine vacuum opened them, and a spring closed them. Good for low speed operation.
Ferrari (and likely others) used ballistic valves on their F1 cars. The camshaft had a big straight line in the profile, which was designed to accelerate the valve rapidly enough to allow the valve to lose contact with the cam lobe. Maximum lift and duration at higher RPMs. Short life though.-
You're completely right on the first one. We have several old hit and miss engines laying around where I work, and a few of them do have the atmospheric intake valve. I guess they work alright if your engine only turns at about 600 RPM.
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<img src="http://www.home.no/andreas.sunnhordvik/mekanisk/Valveless/Principle.jpg" width=500>
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The Aspin Rotary Valve system was similar to the rotary valves on flugelhorns (see below). It was used on British aircraft engines and marketed for automotive use. I don't think it ever really opened up to any long term success.
<img src="http://upload.wikimedia.org/wikipedia/commons/6/6c/Cilindros.JPG"> -
I was just reading about the first airplane diesel engine buillt by Packard. It was a 9 cylinder radial engine with adisplacement of 980 cubic inches and produced 225 hp. It weighed 500lbs. It had one valve per cylinder for intake and exhaust. The downfall was the exhaust fumes, it was said that the pilot looked like an old Indy 500 driver with black soot all over his face.
_http://www.oldengine.org/members/diesel/Duxford/Aviat.htm -
The disc valve.
<img src="http://douglas-self.com/MUSEUM/POWER/unusualICeng/RotaryValveIC/KM8%20torpedo%20a.gif" width="500/">
From http://douglas-self.com/MUSEUM/POWER/unusualICeng…
"Cross-section of a Junkers Jumo KM8 disc-valve engine, enclosed in its torpedo casing.
The disc valve is visible on the right side of the engine, just above the piston.
The engine had eight liquid-cooled cylinders of 90mm bore by 85mm, stroke arranged as a V-8 with a 90deg angle. The total swept volume was 4.34 litres and the compression ratio was 6.6 to 1. Output was 275 HP at 3650 rpm. It ran on a mixture of petrol, oxygen, and its own exhaust gas- the latter presumably to dilute the oxygen to a manageable content.
A production order for 100 engines was issued towards the end of WW2 but was never completed. A prototype was examined by British and American intelligence engineers, who concluded it was "a progressive trend in automotive development." It would appear they were wrong. "
Go here to waste several hours of your time, the Museum of Retro Technology, especially the section on unusual internal combustion engines: <a href="http://douglas-self.com/MUSEUM/museum.htm” target=”_blank”>http://douglas-self.com/MUSEUM/museum.htm -
Radial valves, à la MV Agusta and Honda's RVFC.
<img src="http://dmoto.free.fr/images_diverses/RFVC.jpg"> -
I'm going to go with BMW Valvetronic. Yes, I know the actuation is a conventional OHC setup, but it's similar to the Fiat Multiair in that altering the amount of valve lift (in this case with a separate eccentric shaft and levers and followers controlled by a stepper motor) takes the place of a traditional throttlebody, so the valves perform double duty.
<img src="http://www.bmwinformation.com/img/vt.jpg"> -
Is VTEC-E considered "non-traditional"?
<img src="http://suspendedhatch.thecarthing.com/gassavers/VTEC-E_diagram.gif"> -
Stepped Piston intake
<img src="http://users.breathe.com/prhooper/prinpcd5.gif"> -
The strangest cam/valve setup I've ever seen was on a small engine at the Flywheelers antique tractor show. It wasn't in any vehicle, and I have no idea what it came out of or was used for. It was running, though, and watching it completely blew my mind. You knew instantly what it was doing…how it worked….but the first thought was "WHY?!?!?!?!"
The cams were PERFECTLY ROUND, i.e. their circumference was always the same distance from the axis of the shaft. They were still able to open the valves, though, because these cams varied in thickness; the rocker rested on the SIDE of the cam, and it opened the valve each time the thickest portion of the cam moved past.
This was several years ago. I didn't have a camera with me.-
It sounds like a face-cam, Chater-Lea made some motorcycle engines with that style of valve gear in the 1930s.
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2 exhaust valves, no intake valve, my favorite engine, the Detroit Diesel 2 strokes.
<img src="http://static.howstuffworks.com/gif/diesel-two-stroke.gif"> -
The Mercedes-Benz 300SL used desmodromic valves, too. That was the first use I'd ever heard about them, when I was a kid in the '60s. And then of course the Ducatis, like the Desmo.
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Shit. Day late, and a lot more than a dollar short.
I will just say that I have a Desmo shirt that is that damn exact picture in the lead. And that, as a Ducati owner, it is more of a badge of honor than any kind of headache. -
How about the Intake-Over-Exhaust valve arrangement, as seen in old Land Rovers: http://en.wikipedia.org/wiki/IOE_engine
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I'm super late on this one, but I have to nominate the 4-valve per cylinder, single-overhead cam Triumph Dolomite Sprint.
[img ]http://cache.gawker.com/assets/images/comment/12/2011/03/1d5d6368189d483982592fbb72867b00/340x.jpg[/img]
the single camshaft operated directly on the two intake valves per cylinder, and a pair of rockers off the camshaft operated the exhaust valves. Very weird. Maybe BL didn't have the money for an extra camshaft? Entirely possible.
What's weird is that Saab took this same engine, changed up a few things, and brought out a 16 valve version of it in 1985. With the proper amount of camshafts. Which was reliable. Sorta.
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