FIELD: power engineering, oil and gas industries, agriculture, transport; internal combustion engines. SUBSTANCE: according to first version, mixture of oxidizer and fuel, excess oxidizer coefficient α > 0,8,, is delivered into engine working space, is compressed to self- ignition and combusted with formation of combustion products and execution of mechanical work. Oxidizer and fuel are delivered into working space separately. Fuel charge is delivered and/or simultaneously, and/or after, and/or separately from oxidizer and/or together with oxidizer. Fuel charge can contain water and/or steam, and/or additions, and/or combustion products, and/or other fuel differing in content or phase and/or mixture of fuel(s) and/or oxidizer(s). Description of second version is given in description of invention. Invention provides optimum combustion process (complete combustion) at increased efficiency and engine power output, reduced concentration of harmful substances, reduced heat and mechanical stresses. EFFECT: improved performance of engine. 24 cl, 1 tbl, 1 dwg
