CONTROL APPARATUS FOR INTERNAL COMBUSTION ENGINE

摘要

An ECU (20) after the cranking is started performs a control such that the first combustion cycle is executed on a CPS equipped cylinder (step 100). After that self ignition occurs in the first combustion cycle and the in cylinder pressure changes. The ECU (20) detects change of the in cylinder pressure by using a cylinder pressure sensor (22) and acquires the maximum value thereof as a value Pmax (step 102). Next the acquired value Pmax is corrected on the basis of the engine coolant temperature or the amount of in cylinder air (step 104). The ECU (20) pre stores the relationship between the value Pmax and the octane number (RON) as a map. The ECU (20) determines the octane number (RON) that corresponds to the value Pmax from the map (step 106).