Published on Sep 20, 2019
Nano IC Engine
Nanotechnology in mechanical field is the internal combustion engine on a nano scale, which we have chosen as our area of interest. Heat engines have evolved from external combustion engines to internal combustion engines and the hot off the block is the nano internal combustion engine.
Construction of "Nano" - A 0.1cc Compression Ignition Engine
The Nano is a 0.1cc (that's less than 0.01 cuin) compression ignition engine - most frequently, if somewhat inaccurately, referred to as a "diesel". It was designed by Richard Gordon and the plans were included as a supplement with the British Magazine Model Engineer in the early 1990's.
An idea of the size of the Nano is given by this picture. From backplate to drive washer is less than 1 inch. There are no exotic materials required. The crankcase is hacked from a solid cube of aluminium 3/4" on a side. The piston and contra piston are cast iron. The crankshaft and liner are any old steel from the scrap box.
Here is an exploded view of the engine. The odd looking thing in the foreground is a special Nano-Spanner required to tighten the backplate. It also fits the fuel nipple. The construction is extremely conventional - only the scale is unusual.
Like all model IC projects, there are a few special jigs and tools required to construct the Nano. All are fully detailed in the plan, which includes step by step instructions with photos. The cutter is made from water hardening drill rod (called "silver steel" in the UK because of its appearance - it contains no silver).the teeth are formed of Dremal-type cut-off wheel.
The cutter is used to form the exhaust ports in the cylinder. There are three of these, spaced at 120 degrees with sufficient space between them for the angled transfer ports to slightly overlap the timing. The crown of the piston is conical to assist transfer. The contra piston has a matching concave conical depression.
The venturi is machined separately and secured with Lok-Tite before the final reaming of the crankshaft journal. Notice the three transfer passages in the photo. These terminate in a transfer belt below the cylinder seat that matches with the cylinder transfer ports. If you look very closely, you'll also see the stuff-up that turned away part of the venturi opening.
There's nothing special in the crankshaft components. Another jig (not shown) is made to hold the shaft in the 3-jaw chuck, offset by half the throw for forming the crank pin. Even at these sizes, final lapping to size is no different from larger engines in terms of the amount of metal that must be LEFT for removal. Only the microscopic size makes things difficult. The prop driver knurls were formed with a thread form tool, set on edge and used as a shaper. The prop nut is anodized in the usual way.