Rotary valved engines

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Ben91069
Posts: 13
Joined: Sat May 20, 2006 2:44 am
Location: Dayton, OH

Post by Ben91069 »

Again, what are actual the advantages for production automobile engines? :roll:
The advantages are obvious. Less internal power consumption means you can manufacture a smaller displacement engine with the same power. A smaller displaced motor uses less fuel.
You'd have to give real world details of work showing efficiency improvements for full sized engines, the fact that no racing team even considers them proves that the gains are negligible or even that losses may result.
I dont have to give real world details to show anything. This has already been done and I am not trying to convince anyone to buy them. This is just a pet project.
Call me a nasty old sceptic but rumours and suggestions don't convince me, if someone can quote good data I'll buy it, if not then it's spam perpetuated by the enthusiastically uninformed.
I didn't know I was posting this to convince anyone. I am not trying to convert people to like my idea. If you don't subscribe to this idea, please begin a post of your own on what design you do like.

Anyone know what a fuel cell is? :shock:
Yes, we do. It goes against everything you suggest is keeping manufacturers from designing and manufacturing a rotary valve - capital, research, etc. But yet this is what they are starting to make. Tell me why a fuel cell is better when it is 100 times more complex in manufacturing and design than a simple rotating shaft?
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magic9r
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Joined: Thu Mar 23, 2006 6:30 pm
Location: Sheffield, England

Post by magic9r »

Just ignore me, I love a good discussion and really can't help myself;

so if anyone's interested they should red the coates site do read really carefully, there are parts which are a real hoot!

A very good example is the following passage, note that they quote the data for the coates engine where it looks good & miss out the really important bits, they fail to address flow for partially open valves, there's a really good reason, theirs are like a brick wall at partial openings, they miss out power figures for their engine, can't imagine why :roll:

"The Coates Spherical Rotary Valve Engine is the most advanced in the world, with the most positive valving system ever built. The breathing capabilities of the system are almost double that of a poppet valve. For instance: a static test of a five-litre poppet valve engine on an airflow machine produced a reading of 133 cubic feet per minute (CFM) with valve fully opened. The five-litre Coates Spherical Rotary Valve Engine on the same machine, however, produced a reading of 319 CFMs fully opened; a colossal advantage in airflow comparison. A five-litre poppet vavle engine tested on a dynomometer under the same loads and conditions at 5500 produced 480 BHP and 454 foot pounds of torque. The maximum RPMs on the poppet valve engine were 5700 RPMs; the Spherical Rotary Valve Engine in comparison reached 14,850 RPM's"

And given that my old 1991 Suzuki 400 Bandit revved cleanly to 14000 rpm and had a compression ratio of 11.8:1 and my current Kawasaki ZX-9R redlines at 12000 rpm & has an 11.5:1 compression ratio, both running on nasty unleaded makes the following passage from the site somewhat heavy on BS;

"The answer to this problem was to lower the compression ratio of all engines to 10 to 1 or lower, thus reducing efficiency of the combustion engine to approximately 24 percent. This means less miles per gallon (MPG), lower brake horse power (BHP) and lower torque. The air traveling in through the inlet venturi of a combustion engine inlet travels at a speed of up to 450ft a second. In normally aspirated engines this works fine, but in poppet valve engines, the BHP and torque decreased as the air traveling in does not increase in speed unless a turbo or supercharger is incorporated. At higher RPMs the poppet valve tends to float or bounce and is unable to service the cylinder and chamber to capacity with air and fuel mixture. This is the reason for adding two extra valves to modern engines, causing unburned fuel to escape through the exhaust system which leads to a loss of power, lower MPG and produces significant pollution."

If the bit about poppet valves not flowing well is true then Coates have proven that F1 cars without turbo's cannot work, explain that one to Mr Schumaker anyone?

And although four valve cylinders do suffer less from valve bounce as the valves are lighter and so more easily controlled the primary reason for more valves is that more smaller valves allow more valve area, draw two smaller similar sized circles inside a much larger one, look at the unused area, try again with 4, look how much less unused area, 4 is just optimum from an engineering complexity point of view.

Coates' site looks awful like a fishing hook for investors it seems real short on fact and real long on unproven claims plus some glaring mistakes & BS for anyone who's built & tuned a few 4-strokes in the last 20 years to laugh at, still the boss gets to play with nice toys,
Good luck to him.

Hey! I've got a project engine with efficiency greater than unity, if anyone out there would like to invest......... :wink:
Ben91069
Posts: 13
Joined: Sat May 20, 2006 2:44 am
Location: Dayton, OH

Post by Ben91069 »

You know Magic9r, it sounds as if you have a real problem. I mean, I began this thread in a forum for hobbyists who enjoy anything and everything about internal combustion engines, to share the thought about designing and building a working engine that is unconventional. Nevertheless, you STILL seem to think this thread is all about convincing me that a rotary valve is a bad idea unless you have some data to back it up.

Do you not comprehend? As I stated earlier in my posts, this thread is NOT proving a design to be better than anything else. Do you understand. Get off your rant, because frankly I do not care what you think about this design relative to Formula cars or your precious motorcycles revving so high.

The rotary valve is about mechanical efficiency. Any valving system will compromise airflow in some way and this is not the point of designing a rotary valved engine. The whole point is to eliminate mechanical loss. It has nothing to do with how many RPMs a motor will turn. Your bikes rev so high, because they generate peak torque and power in that range, because of the cam profile matched to the airflow and compression ratio, in addition to light valves on a very small engine. So what? Without a cam and valves, a rotary valve engine with the exact same flow specs will generate more power because it isnt wasting it to operate a conventional valving system. Do you get my point? I do not care about flow ratings or what so and so says this or that will do. I am concerned only with making a design and possibly a model that works. Is this such a huge controversy to you that you immediately knock it down as being so wretched that no one can post their ideas - or are you just trying to be some sort of internet dictator?
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magic9r
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Joined: Thu Mar 23, 2006 6:30 pm
Location: Sheffield, England

Post by magic9r »

Apologies Ben,
I suppose I sometimes get a bee in my bonnet when I see unproven theory touted as fact with no evidence,
I'm out of this one then, it's all yours,
Regards,
Nick
Ben91069
Posts: 13
Joined: Sat May 20, 2006 2:44 am
Location: Dayton, OH

Post by Ben91069 »

Apologies Ben,
I suppose I sometimes get a bee in my bonnet when I see unproven theory touted as fact with no evidence,
I'm out of this one then, it's all yours,
Regards,
Nick
I appreciate you standing up like a man with an apology. I did not claim everything Coates said was fact. Of course they are trying to sell a product. The only fact I can claim is that it is "mechanically efficient", which is common sense.

Thanks again.
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john 58

rot valve

Post by john 58 »

I have a rotary valve cam-am motor cycle works good for 32 years ...hope the design gets on market...john
Ben91069
Posts: 13
Joined: Sat May 20, 2006 2:44 am
Location: Dayton, OH

Re: rot valve

Post by Ben91069 »

john 58 wrote:I have a rotary valve cam-am motor cycle works good for 32 years ...hope the design gets on market...john
It surprises me that the design has actually been used on an engine in service. I did not know this. Was this bike a production bike or something built for racing? Do you know anything about how they sealed the valve or if it is a 2 or 4 stroke?
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Michael_Moore
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Joined: Wed Sep 29, 2004 1:13 pm
Location: San Francisco, CA

Post by Michael_Moore »

Here are some photos of a rotary valve head someone I know built for a small Honda thumper engine

Image

Another friend built a cylindrical rotary valve race engine back in the 1960s as a teenager, and later converted a TZ250 Yamaha to cylindrical rotary valve and you can see some photos here:

http://www.tonyfoale.com/gallery/Engines/index.htm

cheers,
Michael
User avatar
1978enco
Posts: 21
Joined: Tue Jul 11, 2006 6:04 am

Post by 1978enco »

Maybe some kind of magnet might help with the "valve bounce". An electric magnet could be worked into the timing. So that the magnet is on only when the valve is open and closed. Thus keeping it in place without a spring to rob the power
Diesel II
Posts: 124
Joined: Sun Jul 23, 2006 10:58 am
Location: Tyrone GA

Post by Diesel II »

I also thought of a rotary valve engine in the late 80’s and early 90’s. I was working on 2 stroke Detroit diesel engines. Of course there is no intake valves because they are two stoke and the cylinders are ported. I thought it would be a fun project to make a rotary valve head would only need to worry about the exhaust valves. And think what kind of Jake Brake you could make using a rotary style valve. Would be easy to change valve timing without hitting the pistons. Think about the breaking ability. I think the real issue is lubrication and sealing.
swarfed
Posts: 1
Joined: Sat Sep 09, 2006 1:22 am

production rotaries

Post by swarfed »

Are there no snowmobilers here? Skidoo (Bombardier) has been using rotary valved engines in their sleds for a few years now. I think their watercraft may have them too. They're not spherical rotaries like the Coates engine, but they're a production rotary engine nonetheless. And I suspect their valve system would be much easier to duplicate than the Coates.
john58
Posts: 29
Joined: Sun Jan 05, 2003 3:08 pm
Location: n.s. can.

Post by john58 »

The canam engine is a2 stroke motor cycle made by a canadian co mpany till 1982 . mine is a 1974- 175 cc and puts out 24 hp with even pwr .band/ ..Its still all orginal ,I don't use it as much its getting harder to get back up after a spill....john
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