Ignition timing control for internal combustion engine having a dual induction type intake system

摘要

Internal combustion engine having an intake port formed in cylinder head and a first and second intake passages both connected with said intake port. The intake passages are respectively provided with throttle valves and the throttle valve in the second intake passage is opened only under a heavy load operation. The ignition timing is advanced when the throttle valve in the second intake passage has been brought into operation.