An engine capable of use with multiple different types of fuels including gasoline, alcohol based fuels, and heavy fuels such as diesel, JP5, JP8, Jet A, and kerosene based fuels. The engine (10) includes a main cylinder (25) having a compression chamber (26) at one end and a piston (31) that is movable along the length of the cylinder (25) and which connects to a crankshaft (23) for the engine (10). A fuel delivery system (72) delivers a combustible mixture of fuel and air through a fuel delivery valve (73) into the combustion chamber (26) at a sonic velocity of flow such that the fuel is substantially atomized into the air of the combustible mixture delivered to the combustion chamber (26). The combustible mixture is ignited by an igniter (160) within the combustion chamber (26) to urge the piston (31) along the cylinder for driving the crankshaft (23) of the engine (10).