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
"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.........