Duke Engines' incredibly compact, lightweight valveless axial engine - 0 views
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The Duke engine is an axial design, meaning that its five cylinders encircle the drive shaft and run parallel with it. The pistons drive a star-shaped reciprocator, which nutates around the drive shaft, kind of like a spinning coin coming to rest on a table.
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The reciprocator's center point is used to drive the central drive shaft, which rotates in the opposite direction to the reciprocator. "That counter-rotation keeps it in tidy balance," says Duke co-founder John Garvey. "If you lay your hand on it while it's running, you can barely detect any motion at all, it's quite remarkable." That's borne out by the video below, where the engine revving doesn't even cause enough vibrations to tip a coin off its side.
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Instead of cam- or pneumatically-operated intake and outlet valves, the cylinders rotate past intake and outlet ports in a stationary head ring. The spark plugs are also mounted in this stationary ring – the cylinders simply slide past each port or plug at the stage of the cycle it's needed for and move on. In this way, Duke eliminates all the complexity of valve operation and manages to run a five-cylinder engine with just three spark plugs and three fuel injectors. The Duke engine ends up delivering as many power strokes per revolution as a six cylinder engine, but with huge weight savings and a vast reduction in the number of engine parts.
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Watch the second video! This is extraordinary. "New Zealand's Duke Engines has been busy developing and demonstrating excellent results with a bizarre axial engine prototype that completely does away with valves, while delivering excellent power and torque from an engine much smaller, lighter and simpler than the existing technology. We spoke with Duke co-founder John Garvey to find out how the Duke Axial Engine project is going."