Patent ID: 7290521

Claim:
A system for controlling an internal combustion engine whose operation is switchable between a compression-ignition operation in which an air-fuel mixture supplied to a combustion chamber auto-ignites to burn owing to compression and a spark-ignition operation in which the air-fuel mixture is ignited to burn by a spark of a spark plug installed in the combustion chamber, comprising: a prohibitive condition determiner that determines whether a predetermined prohibitive condition to prohibit switching from the spark-ignition to the compression-ignition operation is satisfied; and a switching prohibiter that prohibits switching from the spark-ignition operation to the compression-ignition operation when the predetermined prohibitive condition is satisfied, wherein the prohibitive condition determiner includes: a gas temperature regulator that regulates a gas temperature in the combustion chamber; and a discriminator that discriminates whether operation of the gas temperature regulator is normal; and determines that the predetermined prohibitive condition is satisfied when the operation of the gas temperature regulator is discriminated to be not normal.