| Author | Message | ||
     99buellx1 |
Not really. You can only breathe as much air as you have CC's in the engine per revolution. (on a naturally aspirated motor) | ||
| Reepicheep |
Right, but you work harder to breathe it through a smaller opening. Unless a twin was allowed to supercharge, is be good with that.  | ||
| Mog |
I will try this again (for the second or third time between this and another site) http://www.coatesengine.com/files/theme/csrv_vs_po ppet.html Coates and son have poured 10s of millions of personal wealth into this and have been called futurists and also fakes. It has been demonstrated on a set of bikes George and Gregory Coates built (chopper style) and it works. I have seen it and been to the plant. It needs practical application and race engineering but is quite promising.  | ||
| Blake |
Looks like a scam to me. Their emissions claims are beyond plausible for comparison to an equivalent conventional engine. You can't reduce CO,NOX, and CO2 as they indicate and have similar power output. But they would dearly appreciate any further funding you'd care to contribute. | ||
| Blake |
Poppet valves can provide much more optimum opening and closing performance, meaning opening quicker and staying full-open longer. That's important for peak power performance. | ||
| Sparky |
I had a 120cc rotary valve Kawasaki 2-stroke trail bike when I was going to JC and putzing around with my dirt bike riding friends. It was peppy and reliable for what it was. I know it's not exactly like the 4-stroke Coates system but the (rotary valve) concept has worked successfully on countless Kawi 2-smokes. | ||
| Fast1075 |
The rotary valve 2 smoke was top of class power wise because it allowed asymmetric intake timing. Able to make much more power than a strictly piston port motor, but hard to package compactly. | ||
| Trojan |
The rotary valve 2 smoke was top of class power wise because it allowed asymmetric intake timing. But was still beaten by Yamaha with a much more simple reed valve motor. Rotary valves are nothing new in 4 stroke motors and have been around for donkeys years. getting them to work better (at reasonable cost) than conventional valves is the problem. We all know that there are theorectically better engineering solutions to many things (motorcycle forks for instance) but making them commercially viable is one thing and getting customers to accept them even harder. A few years ago a company called Orbital built a 2 stroke car engine that was far more powerful and more economical than the equivalent 4 stroke motor. Ford bought the rights to the engine and pronmptly buried it deep so that it didn't challenge their own 'lean burn' 4 stroke concept  | ||
| Blake |
>>> Ford bought the rights to the engine and promptly buried it deep so that it didn't challenge their own 'lean burn' 4 stroke concept. Doubtful popular urban myth scenario. | ||
| Trojan |
Doubtful popular urban myth scenario look it up I remember seeing with my own eyes a Ford Fiesta fitted with an Orbital 2 stroke motor. It was a very exciting and well documented project until Ford got hold of it, then nothing..... | ||
| Mog |
 A rotary valve CSRV and a rotary intake (Kawasaki type) are entirely different by a long shot. Poppet valves are the bane of current car and motorcycle internal combustion engines. Port openings of a CSRV (a rotating sphere with large passages cut through the sphere) have huge allowance for the rapid and voluminous gas throughput. If there are folks truly interested in the operational dynamics and credible testing of the CSRV, then maybe this portion of the discussion can be transferred to another area (or keep it here) and I will be happy to pass along data for that discussion at anyone's request. | ||
| Blake |
It's a far leap from seeing an engine in a car to "Ford bought it to kill it." I can't find any credible news source affirming such a story. The opposite appears true, Ford actually had a test fleet running to evaluate the engine: http://www.apnewsarchive.com/1993/Ford-Signs-Deal- With-Orbital-for-Two-Stroke-Engine-Production/id-5 48abcf6270aa0b4fef14f4a5f4ba565 I don't think even Orbital is still using 2-stroke tech. DFI 4-stroke is much more efficient, quiet, low-emmissions, and user-friendly. How many customers want to have to fill up both oil and fuel? Ford spent a lot of money testing the thing and found it lacking. The Eco-Boost engines are spectacular. | ||
| Blake |
>>> Poppet valves are the bane of current car and motorcycle internal combustion engines. Complete and utter baloney. | ||
| Hughlysses |
I don't think even Orbital is still using 2-stroke tech. DFI 4-stroke is much more efficient, quiet, low-emmissions, and user-friendly. How many customers want to have to fill up both oil and fuel? I'm pretty sure the Orbital design uses a external Roots blower for scavenging instead of the crankcase, so a regular 4-stroke-type pressurized oil system is used (no oil addition/mixing required). The utter simplicity of a 2-stroke compared to today's complex 4-strokes is appealing, but I'm sure there are good reasons this didn't make it to production. | ||
| Reepicheep |
I rebuilt a rotary valve Kawasaki... very cool design, but putting the carb on the side of the motor was a disaster, and maintenance was much worse than reed valves. That motor did make great power, but in the long run, my KDX motor with a KIPS valve seems more durable, easier to package, easier to maintain and just as effective. I've envisioned rotating sphere valves before. I imagined they would give phenomenal potential valve train RPM (as they spin continually instead of changing direction). But I bet they are a nightmare to "seal" reliably and durably. And having very high valve train capability probably doesn't help you that much at the end of the day, because modern valves have already achieved speeds very close to where the piston speed becomes the next bottleneck in the system... so faster valves would only give a minor improvement in return for having to solve a whole new class of problems making them work. Why bother when you can just turbo charge or super charge or direct inject the motor and get major performance improvements for less work. | ||
| Mog |
 Baloney? I guess so, for the uninformed Blake. Reepiccheep got it much more correct, although, I have never seen a Ford (Windsor) engine turn 14,850 rpm with poppet valves and do not suppose I will see it done again without the Coates CSRV. Here is an excerpt conclusion from a lab test run on that V8 using the CSRV......... 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 areading 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, The Coates Spherical Rotary Valve comprises two spherical rotary valves assembled on two separate shafts - one for inlet and one for exhaust. They rotate on ceramic carbon bearing with no oil lubrication, the spheres do not make contact with any part of the housing. Theseals are a floating type and are also made of a ceramic material. They have two piston rings and are floating in a small cylinder-type chamber, they are activated by the compression and the combustion strokes of the engine which allows 100 percent sealing effectiveness, when compressed. Because the valves rotate away from the combustion chamber and are vented and charged on the opposite side of each sphere, this creates a lower combustion chamber temperature, allowing for higher compression ratios to be used thus creating an extremely efficient engine. Some of the Coates Spherical Rotary Combustion Engines are at 12 to 1, 13 to 1, 14 to 1 and 15 to 1 compression ratios depending on the application. | ||
| Blake |
bane (noun): a cause of great distress or annoyance. >>> Poppet valves are the bane of current car and motorcycle internal combustion engines. Like I said, complete and utter baloney. "static test" How do they compare in a dynamic test, as if the engine were turning? A rotary valve is always opening or closing, never remaining fully open. A poppet valve may remain fully open for a significant duration. Thus comparing performance capabilities based on static flow is about worthless. "the Spherical Rotary Valve Engine in comparison reached 14,850 RPM's" Poppet valve engines routinely reach 18,000 RPM. So? You do understand that engine efficiency goes to heck at high speeds, yes? So, for street vehicle use, we understand that poppet valve technology today is incredibly reliable and durable. We also understand that poppet valve performance is very efficient with the added bonus of aiding turbulence for improved air/fuel mixture inside the combustion chamber. We also now understand that being able to control and even vary valve timing and valve opening duration is very helpful to both performance and efficiency. Do rotary valves have advantages? Sure. Fewer parts is one. Are the spherical rotary valves superior for durability or performance? No. Do they have disadvantages? Yes. Are poppet valves today the cause of great distress or annoyance in car and motorcycle engines today? No. Mostly they are never even thought about. Modern engines just work. I think you misread that article, which is very deceptively written. It certainly is not objective. | ||
| Bads1 |
Now lets get back to talking about racing!! | ||
| J2blue |
Yes, please, and thanks. How did the boys fair today? Or do they only race tomorrow? | ||
| Blake |
Thanks Dana! Tomorrow | ||
| Mog |
No less objective than your interpretation. Utter baloney. The CSRV is far more durable and superior. At least you got that it has advantages, so lets cut the baloney stuff. Time will tell, so keep a more open mind and a bit more reading Blake. As for todays timings, the KTM is a bit faster so far. The real eyeopener was a Daytona class bike at the front of the grid surpassed some KTM and EBR times, I hope that gets fixed. Should be a great race on the puter screen.  | ||
| Bluzm2 |
Mog, you do know that Blake is an engineer right? Pretty open minded regarding ALL things mechanical... Particularly if they burn dead dinosaurs.. | ||
| Doerman |
That went pretty well for the EBRs ! | ||
| M2typhoon |
Cory really stepped up!! | ||
| Mog |
Sorry, wouldn't know him, I retired at the age of 46. I will be 70 in the not too distant future. In the old days at Sperry Univac and Prime Computer, the engineers with whom I worked seemed different. Same with the folks with whom I worked at GE, Textron, Hughes, Sangamo Weston, Imo De Laval, AMP, Landis Tool, Greis Dynacast and Ford to mention a few. My helmet is off to Blake. I will go to the garage, take out the old Buell 1125R and do penance tomorrow.  | ||
| Xb1125r |
Wow how does one retire at 46! Must be nice | ||
| Bads1 |
We finally get to see the Laguna round on TV and Miller is this weekend and its not televised neither. | ||
| Sparky |
If Miller is approx Salt Lake City according to CBSSN, they are televising Miller rounds live and encores. | ||
| Crusty |
Here's the schedule: http://www.amaproracing.com/rr/events/tvlistings.c fm?year=2013 | ||
| Firstbuell |
for races NOT being on TV, add the XR1200s at Indy MotoGP AMA Pro offers live streaming of fixed cams instead..... |
