Abstract: A piston structure for an internal combustion engine which utilizes fuel injection to furnish the engine charge. To provide a more effective operation, and to more fully utilize the air induced into the engine, the piston face is formed with a main cavity as well as with one or more supplementary depressions spaced away from the main cavity whereby to promote turbulence at the combustion chamber and consequently a better fuel-air mixture during a power stroke.

Abstract: A thermal reactor adapted to receive hot exhaust gases generated as the result of the combustion of a hydrocarbon fuel within an engine. The hot exhaust gas stream taken directly from the engine, is passed into a chamber where it reacts with air, preferably in the presence of a reaction promoting element. However, prior to the reaction stage, the hot gas is urged into a swirling motion and through a constricted passageway whereby to provide through a longer dwell period, better mixing, and avoid direct impingement of the gas against the catalyst bed surface when the latter is utilized.