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An internal combustion engine (ICE) is a heat engine in which the oxidation of a fuel–air mixture occurs inside the engine itself, within one or more cylinders, and the resulting high-temperature, high-pressure gaseous products act directly on a piston, rotor, or nozzle to produce mechanical work ^[1]. Energy is released by rapid combustion—either spark-ignited burning of a premixed charge or compression ignition of injected fuel—that converts the chemical enthalpy of the fuel into cylinder pressure, which is then transformed through a reciprocating or rotating mechanism into shaft work ^[2]. Reciprocating ICEs are classified by thermodynamic cycle as four-stroke or two-stroke devices and by ignition mode as spark-ignition (Otto) or compression-ignition (Diesel) engines, with air-standard cycles serving as idealized reference models of the real process ^[3]. The engine converts the expansion of hot gas against a moving boundary, transferring work through a crankshaft or turbine, and exhausts the products of combustion to the environment ^[2]. It is distinguished from external combustion engines, in which combustion takes place outside the working cylinder, by the internal conversion of chemical fuel energy to mechanical work ^[1].