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 Mazda RX-7s
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 Reed valve fitted peripheral intake port Wankel
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urquiola
Apprentice

Spain
96 Posts

Posted - Jun 08 2010 :  08:52:36 AM  Show Profile  Reply with Quote
I guess I'm approaching my incompetence level, as I can't offer nothing more than speculations, sorry no mechanical abilities at all. Some degree of exhaust gas recirculation is probably inevitable in rotaries, but this doesn't need to be specially negative for the overall engine performance, and any degree of backflow of exhaust gas into the intake manifold or duct, that took place in some peripheral intake peripheral exhaust rotaries is a much more catatrophic event, that can be fully eliminated with a reed-valve, acting as an unsurmontable wall for backflow. A very small amount of exhaust gas taken into the next cycle or recirculated, the wording you prefer, can be regarded as no recirculation at all, if it doesn't reach the amount that produces misfirings - or 1 ignition in 3 turns functioning -, that was seen early in the development of Wankel engine. (About the flexion of seals, SAE Paper 840035 by J Knoll et al.,seems to deal with the subject; regarding the shape, number and placement of ports, and shape of duct-chamber edge, the book by R.F. Ansdale, Iliffe, 1968, The Wankel RC Engine Design and Performance, pp 14,15 & 85, contains a detailed discussion of all this, and also a diagram on the degree of port overlap that is currently used in the Renesis engine). See you later...

Edited by - urquiola on May 05 2012 7:19:12 PM
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urquiola
Apprentice

Spain
96 Posts

Posted - Jul 22 2010 :  11:50:51 AM  Show Profile  Reply with Quote
Attached please find a hand sketch of my concept of peripheral intake side exhaust RCE. (Sorry, don't know how to use MS Paint) If you simulate it, you'll notice that overlap is minimal to nil, and that prismatic reed-valve greatly decreases EGR at part load, low rprm, and that the increase in MEP it gives improves sealing,emissions and fuel use. Maybe Renesis has a similar practical fuel use as RX7, but it is much more powerful. We all would greatly appreciate you letting us know the reference on the RCE simulation application you have, it will give all of us lots of fun!. Salud +

Download Attachment: Periph int side exh Wankel RCE 2.jpg
56.81 KB

Edited by - urquiola on Aug 22 2010 05:05:18 AM
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Aaron Cake
Administrator

Canada
6705 Posts

Posted - Jul 25 2010 :  10:43:20 AM  Show Profile  Visit Aaron Cake's Homepage  Send Aaron Cake an ICQ Message  Send Aaron Cake a Yahoo! Message  Reply with Quote
But without the peripheral exhaust ports, the peripheral intake ports don't have nearly as great an advantage. Without that high RPM overlap, high RPM power drops off greatly.
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urquiola
Apprentice

Spain
96 Posts

Posted - Jul 26 2010 :  06:12:16 AM  Show Profile  Reply with Quote
Well, power drops very little at high rpm, you can look at the Yanmar Diesel RCE data. Wankel was a highway, high rpm engine, its good zone started at 3'000 rpm, it is less well adapted to city or low rpm driving, and that is the regime where Reed Valve can be an advantage. With a HighWay speed limit of 55 mph, an engine able to give 230 Kw and run at 8'000 rpm is most of time underused and in its bad performance range. If you open up the intake port early in the cycle, you gain in low rpm torque and engine driveability, such in a truck engine. Low rpm power tuned engines use long intake ducts; for high speed power, ducts must be shortest as possible; ducts are also tuned for resonating waves reaching a high pressure point close to the intake port opening, to improve engine filling. The Peripheral Port advantage is a higher Mean Effective Pressure throughout the whole rpm range. Thanks, salud +

Edited by - urquiola on Aug 22 2010 05:06:15 AM
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Aaron Cake
Administrator

Canada
6705 Posts

Posted - Aug 19 2010 :  09:22:47 AM  Show Profile  Visit Aaron Cake's Homepage  Send Aaron Cake an ICQ Message  Send Aaron Cake a Yahoo! Message  Reply with Quote
True enough. But consider this: by just using a regular side port engine (with or without peripheral exhaust ports), overlap can be kept to a minimum at all RPM ranges. Then a small turbocharger (such as a GT30R) can be used which will provide response from 1500RPM until about 7500 RPM, put down 300HP/300 FT-LBs and maintain easy low load driving due to conservative porting.

I think the NA rotary was great in it's day, but today the rotary can't compete without forced induction. Which is fine with me, because the rotary is perfectly suited to turbocharging.
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Aaron Cake
Administrator

Canada
6705 Posts

Posted - Aug 29 2010 :  10:53:13 AM  Show Profile  Visit Aaron Cake's Homepage  Send Aaron Cake an ICQ Message  Send Aaron Cake a Yahoo! Message  Reply with Quote
Something is weird here. The index shows the original poster replied today at 5AM, yet his reply isn't here...

TESTING
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urquiola
Apprentice

Spain
96 Posts

Posted - Sep 01 2010 :  03:47:36 AM  Show Profile  Reply with Quote
What I added were changes in the first entry on the subject, now deleted, perhaps it was a mouse mistake.... If you deem appropiate, you can delete this. By the way: Are you aware of somebody that can install a Norton rotor (already bought) in a Sachs air cooled engine from an Hércules / DKW W-2000 Motorcycle? Some dynamic balancing is needed, as the weight of Norton rotor, that has cooling fins, is heavier than the original Sachs rotor. The resulting engine would be installed in a Citroen A series car (see www.mcda.com ) whose air cooled flat-twin engine has the same displacement and turns in the same direction as the Sachs KC 24 engine. Rules here are very strict, it's extremely difficult having an approval for installing a turbo or other major changes in an existing car or engine, if you want to continue using it legally on streets or roads. On the overlap subject, some exhaust gas recirculation (EGR) is unavoidable, as the combustion pocket or recess in the rotor always has some burnt gases at the beginning of admission stroke; the kind of EGR you can expect from a RV system is probably not much greater than this, and for sure, can be computed and assessed. Exhaust Gas Recirculation was a way used in reciprocating engines to reduce NOx emissions, I discussed this before.

Edited by - urquiola on Jan 01 2013 4:04:34 PM
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urquiola
Apprentice

Spain
96 Posts

Posted - Oct 02 2010 :  11:09:10 AM  Show Profile  Reply with Quote
In the magazine Popular Science, year 1974, you can find lots of interesting things related to the development of RCE by several automakers, most of them from Jan P. Norby, a very good expert and historian on the subject; in the same magazine Jan 1967 issue, some rotary engine alternatives to Wankel are described. Anybody knowing the reason why Mazda changed from LDR rotor recess in 1972 or so, to an MDR recess later on ?. Perhaps just production costs and number of machining operations ?
Salut to you all +!

Edited by - urquiola on Mar 24 2012 10:10:39 PM
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urquiola
Apprentice

Spain
96 Posts

Posted - Oct 03 2010 :  03:36:13 AM  Show Profile  Reply with Quote
The german automaker Audi exhibited in an auto show an experimental electric version of his A1, named A1 e-tron. This car has an electric engine and a battery, can go for 50 km, and an small Wankel engine, 245 cc in displacement, to charge the battery and extend the range up to 200 km. There's no drawing of the engine, but they state that it is a single port engine. The concept that comes into my mind is a port, with a movable gate, that opens the port to the intake or exhaust ducts, depending on the phase of cycle the engine is. If it is so, is an idea that I like. Nobody knows if the AudiA1 e-tron car will be ever mass produced. Anybody knowing more about this engine ?. Salut +
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Aaron Cake
Administrator

Canada
6705 Posts

Posted - Oct 09 2010 :  10:35:02 AM  Show Profile  Visit Aaron Cake's Homepage  Send Aaron Cake an ICQ Message  Send Aaron Cake a Yahoo! Message  Reply with Quote
Mazda has used a similar system in their R26B race engine, and something a little simpler in the 2nd gen NA engine (aux ports, then VDI in '89+), then finally a 3 stage variable intake in the Renesis.
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urquiola
Apprentice

Spain
96 Posts

Posted - Jan 08 2011 :  5:10:28 PM  Show Profile  Reply with Quote
I guess the variable intake tubing in the Mazda car that won the Le Mans 24h race was something like a trombone, a short distance tubing from fuel injector to intake port was used to give the best HP at high r.p.m., and a long one to give more torque in the low rotation speed range. Should any of you become aware of somebody implementing the kind of porting I proposed, please let us know !. Happy year 2011, thanks,
salut +

Edited by - urquiola on Apr 01 2012 10:48:36 AM
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urquiola
Apprentice

Spain
96 Posts

Posted - Jan 29 2011 :  07:21:23 AM  Show Profile  Reply with Quote
Attached please find a picture of the Husqvarna Reed Valve

Download Attachment: Husqvarna Reed Valve.jpg
202.25 KB


Edited by - urquiola on Jan 29 2011 07:23:07 AM
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urquiola
Apprentice

Spain
96 Posts

Posted - Jan 29 2011 :  07:32:51 AM  Show Profile  Reply with Quote
This is the side view

Download Attachment: H R-V Side View.jpg
107.73 KB

Edited by - urquiola on Jan 29 2011 07:33:41 AM
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Aaron Cake
Administrator

Canada
6705 Posts

Posted - Jan 29 2011 :  10:19:40 AM  Show Profile  Visit Aaron Cake's Homepage  Send Aaron Cake an ICQ Message  Send Aaron Cake a Yahoo! Message  Reply with Quote
That's a nice reed valve.
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urquiola
Apprentice

Spain
96 Posts

Posted - Nov 04 2011 :  5:57:06 PM  Show Profile  Reply with Quote
Mazda announced they will shut their Rotary Engine production line the next year 2012, after building 1'000 units of the new and, we hope not, final Rx 7. The britons started collecting money from the public some years ago to keep flying the last Delta Wing Avro Vulcan bomber. Anybody starting to emit shares or anything to buy the Rotary Engine line from Mazda, and thus having the Wankel engine alive ? We are many in having lots of fun from these engines, just a good management is needed. Aaron, how do you see yourself as an engine producer in the name of all Rotary Enthousiasts ?. Salut +
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