Neat new concept: http://www.coatesengine.com/technology.html In the late 1960s and 1970s, most vehicles combustion engines in the USA were running at a compression ratio of 12 to 1, which resulted in an engine efficiency of approximately 55 percent. The rest of the engine power was lost in friction, pumping and heat loss. When it was found that lead additives in fuel had an adverse effect on the environment, it was removed from the fuel. This caused the poppet valves and combustion chamber on poppet valve engines to overheat, raising the temperature to in excess of 2500 degrees F and damaging the poppet valves. 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. The poppet valves' stems are lubricated with engine oil which is burned off after a short period of running. The stem of the inlet valve system is also lubricated with engine oil, which is washed off and inducted into the combustion chamber with air and fuel mixture. This slows combustion and produces further emissions and eventually clogs the catalytic converter. Variable valve timing has advantages at lower RPMs as it can shorten the overlap duration of the valves, but has extra moving parts that eventually wear. On quick deceleration, it can cause piston and valve contact where serious damage can occur. Poppet valves, if not activated with hydraulic systems, must have clearance readjusted periodically. The successful poppet valve of the original combustion engine has been used and modified continuously until the present. However, it is the most troublesome part of a combustion engine and has lower efficiency at higher RPMs. Remedy 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, 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. The seals 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.