Kimmel Steam Engine Collection: George Nutz Steam Bicycle Engine and Boiler

George Nutz designed bicycle engine and boiler. This is a very small uniflow engine. The genius of this design is the piston valve in series with the uniflow exhaust ports. To begin with the exhaust ports are drilled in an inch above BDC. The piston valve holds things closed for the down stroke. Just before BDC the piston valve opens and thus there is a long or at least longer time period for exhausting through the uniflow ports. Also the amount of steam left in the cylinder to be recompressed is less, allowing for a smaller clearance volume. This is a very clever design and the first time that I have seen an attempt to change the timing of a uniflow engine.

George Nutz designed bicycle engine and boiler. This is a very small uniflow engine. The genius of this design is the piston valve in series with the uniflow exhaust ports. To begin with the exhaust ports are drilled in an inch above BDC. The piston valve holds things closed for the down stroke. Just before BDC the piston valve opens and thus there is a long or at least longer time period for exhausting through the uniflow ports. Also the amount of steam left in the cylinder to be recompressed is less, allowing for a smaller clearance volume. This is a very clever design and the first time that I have seen an attempt to change the timing of a uniflow engine.
The engine is not completed and so the piston valve drive train is some harmonic drive off an eccentric on the crank shaft. The whole power plant and bicycle were designed for a specific 3 mile run to the post office and back.
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George Nutz Bicycle Engine and Boiler

George Nutz Bicycle
Engine and Boiler