The ST-5 and IC Compared
The ST-5 is fundamentally different from conventional internal combustion (IC) engines. The IC process relies on injecting fuel into the engine and causing it to explode intermittently. The combustion takes place against a cooled cylinder face and under high pressure resulting in high levels of carbon monoxide, unburned hydrocarbons and nitrogen oxides. Since the fuel is injected into the engine, it has to be removed by means of exhaust so that additional fuel may be injected.
With the ST-5, the fuel is burned continuously outside the engine, against hot surfaces and at atmospheric pressure. This results in almost no carbon monoxide pollution. The level of unburned hydrocarbons and nitrogen oxides is much lower than that from IC engines and for most biomass fuels there is no sulphur production. The heat from the fuel is transmitted into the engine by means of a heat exchanger (the heater head) and since no fuel is injected into the engine, no exhaust system is necessary from the engine itself.
The differences between the two systems give the ST-5 significant qualitative advantages. First of all, the need for spark plugs, carburetors, distributors and other fuel injection systems is eliminated. In their place, the ST-5 utilizes a simple burner, very much like a high quality wood furnace. So, in place of complicated parts which are prone to failure, the ST-5 has a simple firebox.
I.C. engines require mufflers to reduce the noise of the intermittent exploding of fuel. Since the ST-5's operation uses a constant flame temperature outside the engine, there is no sound from the fuel-combustion process. Hence, the ST-5 does not have a muffler. In fact, it does not have an IC type exhaust system at all, requiring only a chimney and a means of ash-removal.
Maintenance of conventional engines always involves frequent oil changes, and a used oil disposal problem. The ST-5 takes care of that. Oil and the ST-5 don't mix. If oil were to get into the hot end or the regenerator, it would seriously damage the engine, so the ST-5 is fitted with sealed bearings and dry-lubricated cylinders. This not only protects the engine from the possibility of oil infiltration but frees the user from the trouble of changing oil periodically. It also keeps the environment clean as there are no oil residues or odor.
Because the engine components which make maintaining an IC engine difficult are unnecessary for the ST-5, this power system is extremely simple to keep operating. The mechanical arrangement is about as complicated as a 10 speed bicycle, although the engine itself is considerably heavier. A person with minimal mechanical aptitude, a hoist or assistant, a few universal hand tools (wrenches, a hammer, etc.) and the service manual provided with the ST-5, can completely strip the engine and rebuild it in a matter of hours.
Multifuel capabilities, maximum reliability, low pollution, user-serviceability and quiet operation; all hallmarks of the ST-5 power system!
