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Technology Stocks : Advanced Engine Technologies (AENG) -- Ignore unavailable to you. Want to Upgrade?

To: john griffin who wrote (1477)	7/17/1998 9:34:00 PM
From: shashyazhi	Read Replies (2) \| Respond to of 3383

Initially the OX2 engine befuddles the mechanically unsophisticated person. Even those who have a fairly intimate acquaintance with the conventional internal combustion engine are led astray by the horsepower output from such an apparently small engine. Since the OX2 fires all eight pistons TWICE in one turn of the output shaft, its true displacement is about 264 cubic inches per turn. The Chevrolet 350 takes two full turns, its true displacement is about 175 cubic inches per turn. So comparing the OX2 to a 350 Chevy is not a very valid comparision. I would rather compare it to a motorcycle engine like a Suzuki 1100. That's a fairer comparison, because motorcycle engines do commonly run at 10,000 RPM, while that high engine speed would immediately destroy ANY American built V-8 you would care to name. Piston speed basically assumes that the piston is travelling in a straight line in a cylinder bore with an infinite length. Of course, it isn't an infinite length. But piston speed can be fairly safely used as a rule of thumb indicator of what the highest rpm the pistons, rods and rings can withstand continuously. Another problem is that the piston must start and stop constantly. Mechanical stress on an engine is a squared function. If you double the engine speed, you have four times the stress on the mechanical parts. High piston acceleration causes the rings to flutter in their grooves, allowing compressed gasses to bypass the rings and scorch the oil film off of the mating surface between piston and bore. Lubrication failure follows immediately. The maximum acceleration, G, in feet per second per second is equal to the quantity RPM squared times the length of the stroke in inches divided by 2189. Since the OX2 engine is turning the equivalent of 10,000 RPM when the output shaft is turning 2500 RPM, the calculation becomes G = [ 10,000 X 10,000 X 2.955 ] divided by 2189. The answer is 134,993 feet per second per second. In order to avoid ring flutter, the piston rings can be no thicker than 1 millimeter ( 0.39 inches ). I have worked with piston rings as thin as half a millimeter in high RPM two stroke engines. Those rings wore out very quickly, because they had such extreme rubbing pressure on a small area. In an engine with a conventional crankshaft, some of the pressure of the expanding gasses during the power stroke is wasted trying to push the piston sideways. Therefore, the piston has rather long skirts to keep it aligned with the bore. This causes friction losses. The trend in modern high speed engines is to minimize the width of the skirts by using the "slipper" type piston. It would be interesting to compare the amount of friction losses between a conventional 8-cylinder engine and the OX2 engine using engines of more equal sizes. I would like to see the spark plugs removed and the engines motored on a dyno. I would bet that the OX2 engine probably has less friction than the conventional engine.