Patent ID: 8499546

Claim:
A method for controlling an internal combustion engine, comprising: operating the engine with two phases, a first one of the two phases being an initial temperature operating phase of the engine and a second one of the two phases being a subsequent higher temperature operating phase of the engine, wherein, during the initial temperature operating phase of the engine; operating the engine with an air/fuel ratio varying with a predetermined modulation function F(t), where t is time, having a predetermined period P; and determining, after the predetermined period of time P whether: (A) operating temperature of the engine is less than a predetermined operating temperature; or (B) operating time of the engine is less than a predetermined time and; if it is determined that the operating temperature of the engine is less than the predetermined operating temperature or the operating time of the engine is less than the predetermined time, repeating the air/fuel ratio varying with the predetermined modulation function F(t), otherwise proceeding to operate the engine in the second one of the two phases.