Patent ID: 11933259
Assignee: YAMAHA HATSUDOKI KABUSHIKI KAISHA
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  Y | IPC F

Claim 0:
1. An ignition timing control device for controlling ignition timing of an internal combustion engine of a marine propulsion device, the ignition timing control device comprising:
a storage to store at least one of a first ignition timing map or a second ignition timing map, the first ignition timing map associated with a first fuel, and the second ignition timing map associated with a second fuel that is more likely to cause knocking of the internal combustion engine than the first fuel; and
a processor configured or programmed to function as:
an ignition timing control section to control the ignition timing of the internal combustion engine based on either the first ignition timing map or the second ignition timing map; and
a knocking determining section to determine whether or not the knocking of the internal combustion engine has occurred in a range in which a rotational speed of the internal combustion engine is greater than or equal to a predetermined speed; wherein

the ignition timing control section is operable to:
control the ignition timing based on the first ignition timing map by executing a timing retardation correction of the ignition timing based on the first ignition timing map when the knocking determining section determines that the knocking of the internal combustion engine has occurred; or
control the ignition timing based on the second ignition timing map by executing a timing advancement correction of the ignition timing based on the second ignition timing map when the knocking determining section determines that the knocking of the internal combustion engine has not occurred; and

the ignition timing control section is operable to cancel the timing retardation correction or the timing advancement correction when the rotational speed of the internal combustion engine becomes lower than the range during execution of the timing retardation correction or the timing advancement correction.