Patent ID: 7438665

Claim:
A control system for an internal combustion engine having a plurality of cylinders and switching means for switching between an all-cylinder operation in which all of said plurality of cylinders are operated and a partial-cylinder operation in which at least one of said plurality of cylinders is halted, said control system comprising: operation amount detecting means for detecting an operation amount indicative of a required output power of said engine; condition determining means for determining a condition for performing the partial-cylinder operation based on the operation amount detected by said operation amount detecting means; and instructing means for instructing said switching means to perform the partial-cylinder operation or the all-cylinder operation according to a result of the determination, wherein said condition determining means includes filtering means for performing a low-pass filtering of the operation amount, and determines the condition for performing the partial-cylinder operation based on the operation amount filtered by said filtering means, when the partial-cylinder operation is being performed.