Duke Engines of New Zealand has been busy developing and demonstrating excellent results with a bizarre axial engine prototype that completely eliminates valves while delivering excellent power and torque for a much smaller, lighter and simpler engine than the existing technology. We talked to Duke co-founder John Garvey to find out how the Duke Axial Engine project is going.
The Duke Engines 3-liter five-liter test mule is already manufacturing 215 horsepower and 250 pound-feet of torque at 4,500 rpm, slightly surpassing two conventional 3-liter reference engines weighing almost 20 percent more and Are almost three times as large for shipping purposes. With an innovative, uncovered design, the Duke engine appears to be well on its way to deliver superior performance, greater compression and greater efficiency in an extremely compact and lightweight package with far fewer moving parts than conventional engines.
The Duke engine is an axial design, which means that its five cylinders surround the drive shaft and work parallel with it. The pistons drive a star-shaped reciprocator, which nutates around the transmission shaft, sort of like a spinning coin that comes to rest on a table.
The center point of the alternator is used to drive the central drive shaft, which rotates in the opposite direction to the reciprocator. "This counter-rotation keeps the balance neat," says Duke co-founder John Garvey. "If you put your hand on it while you run, you can barely detect any movement, it's quite remarkable."
This is corroborated by the video below where the revving engine does not even cause enough vibrations to tilt a coin out of its side.Instead of intake and exhaust valves driven by cam or tire, the cylinders rotate past input and output ports In a Stationary Head Ring. The spark plugs are also mounted on this stationary ring - the cylinders simply pass through each port or plug in the stage of the cycle that is needed to and continue on. In this way, Duke eliminates all the complexity of the operation of the valve and manages to execute a five-cylinder engine with only three spark plugs and three fuel injectors.
The Duke engine ends up offering as many power strokes per revolution as a six-cylinder engine, but with great weight savings and a large reduction in the number of engine parts.