Provided is an engine knocking detection apparatus capable of reasonably implementing necessary measures for water and dust proofing and against breaking of a cable, and the like at low cost as well as precisely detecting and effectively suppressing or avoiding knocking while suppressing cost and weight increases as much as possible. The engine knocking detection apparatus is adapted to detect knocking in an engine that adopts a flywheel magneto ignition system with an ignition coil unit securely attached to a cylinder, the ignition coil unit including an iron core, a coil wound around the iron core, and a control circuit board attached to the coil, and has an accelerometer for knocking detection attached to the iron core of the ignition coil unit.

A handheld engine-driven working machine comprises an internal combustion engine and an ignition control device; wherein the ignition control device can switch its control between a normal mode and a operation mode, wherein during the operation mode, the ignition timing within the high speed range is maintained at a second BTDC angle, and the ignition timing within the medium speed range is advanced more than a third BTDC angle between a first BTDC angle and the second BTDC angle, and wherein at any rotational speed within the medium speed range, the ignition timing during the operation mode is advanced more than the ignition timing during the normal mode.

An ignition device for an internal combustion engine is provided which improves ignition while reducing electric power consumption. An ignition device for an internal combustion engine includes an ignition plug that is placed with a tip exposed on an end in an axial direction of a combustion chamber formed in a cylinder and that includes a central electrode and a grounding electrode provided opposing each other at the tip, and a magnetic field former that forms a magnetic field in a direction in which a magnetic field vector substantially vertically passes through an approximate two-dimensional plane including a spark discharge path formed, by a gas flow ejected to the end in the axial direction of the combustion chamber, between the central electrode and the grounding electrode, and extending in an approximate U shape in a direction orthogonal to the opposing direction of the electrodes.

A multiple-keyed crankshaft and flywheel provides for different ignition timing options for an internal combustion engine. The crankshaft of the engine includes multiple keyways set at designated angular displacements of the crankshaft that correspond with keyways on a flywheel for providing different timing options for the engine. The flywheel may be mounted to the crankshaft by aligning one of the keyways of the flywheel to one of the keyways of the crankshaft related to a particular ignition timing selection.

A delayed ignition control device comprises a charging circuit and a delayed ignition control circuit. In the delayed ignition control circuit, the resistor R6 is connected between the positive electrode of the input end of the photo coupling IC and the initial end of the power coil N3; the shut-off switch S1 is connected between the negative electrode of the input terminal of the photo coupling IC and the ground; the collector electrode of the photo coupling IC is connected with the initial end of the power coil N3; the output end of the photo coupling IC is connected with the anode of the diode D5; the voltage holding capacitor C2 is connected between the negative electrode of the diode D5 and the ground; and the resistor R8 is connected with the negative electrode of the diode D5 and the controller electrode of the silicon controlled SCR2.