Abstract: An engine (FIG. 1-1) comprising of multiple cylinders designated (2-5) combustion cylinders and (2-6) for heat recovery steam cylinders, each cylinder having a piston connected to a common crankshaft. The combustion cylinders operate on a four stroke cycle and the heat recovery steam cylinders operate on a two stroke cycle. The exhaust gas from the combustion cylinders is pressurized by a compressor, driven by a turbine, before entry into the heat recovery steam cylinders. This happens during the intake/power stroke of the heat recovery steam cylinders, as the intake valve closes, after top dead center, heated pressurized water is injected into the cylinder and spontaneously turns to steam driving the receding piston down. This heated exhaust gas and steam is expelled from the heat recovery steam cylinders to drive the turbine which in turn drives two compressors, one to compress the exhaust gas and one to compress the intake air.