An internal combustion engine that uses stratification of gasses for compressing air is disclosed. The engine uses a combustion chamber that delivers products of combustion into an elongated compression chamber to drive the products of combustion against resident air within the elongated compression chamber, and push the resident air into a compressed air chamber. After driving the resident air into the compressed air chamber, the products of combustion are used with work-producing devices. Air is then driven into the compression chamber by an air pump or low-pressure compressor to once again fill the compression chamber with fresh air. The air in the compressed air chamber is then delivered to the combustion chamber and used for combustion. Fuel is delivered to the combustion chamber by a fuel injector, and ignited by the heat of the compressed air and/or a glow plug, spark plug, or similar ignition device.