NOVELTY - The system has an internal combustion engine (10) including a combustion chamber (30) i.e. cylinder. An injector (66) i.e. direct injector, provides injection fluid to the combustion chamber. A heated pressurization system (200) heats the injection fluid in a pressure vessel to specified temperature for injecting the injection fluid to the combustion chamber by the injector at specified injection pressure. Another injector (70) i.e. port injector, provides another injection fluid different from the former injection fluid to the combustion chamber.    USE - Engine system for controlling vapor pressure of an injected fluid e.g. liquid hydrocarbon, alcohol and alcohol-water mixture (all claimed), that is injected into cylinders of an internal combustion engine in a vehicle.    ADVANTAGE - The system avoids the need of high pressure positive displacement pump, thus reducing the engine production cost. The system utilizes heated exhaust gas flowing through the exhaust passage as energy source to heat the pressure vessel to provide the injection fluid at the injection pressure for direct injection, thus partially recovering energy losses related to exhaust heat. The injection fluid is heated itself such that the injection fluid pressurization system is less complex. The system is provided with the engine controller adjusting the amount of the injected fluid based on composition, thus accurately controlling combustion to aid in stoichiometric operation. The pressure vessel is heated by heat energy of exhaust gas, so that the potential parasitic loss is reduced, thus increasing the operating efficiency of the vehicle.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for controlling pressurization and injection of a fluid made up of a set of identified substances to a combustion chamber of an engine.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an engine system.    Internal combustion engine (10)    Combustion chamber (30)    Crankshaft (40)    Injectors (66, 70)    Heated pressurization system (200)