An ignition coil unit is attached to an engine body. The engine body includes a cylinder head having a plug hole and a head cover that covers the cylinder head by including an opening hole facing the plug hole. The ignition coil unit includes a coil unit that generates a high voltage and a cylindrical coupling unit that connects the coil unit with a spark plug. The coupling unit includes a flexible sealing section fitting to an outer peripheral surface of the high tension tower and a harder joint fitting to a tip of the sealing section. The sealing section includes an adhesion portion to tightly contact the head cover and a neck portion at least between the adhesion portion and the joint in a Z-axis direction. The neck portion is formed by partially constricting an outer peripheral surface of the sealing section radially inside.

A system and method for generating microwaves for microwave enhanced combustion (MEC) input to an MEC antenna of an internal combustion engine. The system uses a directional coupler to deliver the MEC input signal to the MEC antenna and to receive a reflected power signal from the MEC antenna. A feedback path determines a desired frequency, based on the reflected power and using an impedance-matching controller that matches the reflected power to a desired frequency value. Additional inputs, such as various engine conditions, can also be used to determine the desired frequency.

A method is for starting a combustion engine having a pull-rope starter. A fuel/air mixture is fed to the engine via an intake channel. The mixture is ignited by a spark plug. The combustion drives the piston downward and drives a crankshaft rotationally. The fuel system has a fuel channel opening into the intake channel. An electric fuel valve is open in its currentless state and closes a fuel channel only when an operating voltage is applied. An electronic control unit actuates the fuel valve and triggers an ignition spark and is utilized by a generator to supply energy to the control unit, the fuel valve and the ignition device. To prevent excessive enriching of the fuel/air mixture during starting, the energy, which is generated at the beginning of the rotation of the crankshaft, is used to first close the fuel valve before the control unit triggers an ignition spark.

An internal combustion engine for an aircraft can include a crankshaft configured to drive a propeller; a camshaft coupled to the crankshaft; and an ignition controller coupled to the camshaft and including a visual indicator, the visual indicator configured to produce a visual signal at a predetermined angular position of the engine. An ignition controller for an internal combustion engine can include a housing and a P-lead connection extending from the housing, the ignition controller configured to selectively supply or cut main electrical power from the engine via the P-lead connection, the ignition controller also configured to selectively supply its own power.

In an ignition device, a proportion of a yoke end width defined as a distance from one end to another end of an end portion of each of a pair of yokes in the circumferential direction to a magnet width defined as a distance from one end to another end of a permanent magnet disposed on the outer circumferential surface of a flywheel, in the circumferential direction is in a range of 60% to 100%. Moreover, a proportion of the magnet width to a yoke interval between the pair of yokes is in a range of 95% to 100%.

An internal combustion engine for an aircraft can include a crankshaft configured to drive a propeller; a camshaft coupled to the crankshaft; and an ignition controller coupled to the camshaft and including a visual indicator, the visual indicator configured to produce a visual signal at a predetermined angular position of the engine. An ignition controller for an internal combustion engine can include a housing and a P-lead connection extending from the housing, the ignition controller configured to selectively supply or cut main electrical power from the engine via the P-lead connection, the ignition controller also configured to selectively supply its own power.

An internal combustion engine for an aircraft can include a crankshaft configured to drive a propeller; a camshaft coupled to the crankshaft; and an ignition controller coupled to the camshaft and including a visual indicator, the visual indicator configured to produce a visual signal at a predetermined angular position of the engine. An ignition controller for an internal combustion engine can include a housing and a P-lead connection extending from the housing, the ignition controller configured to selectively supply or cut main electrical power from the engine via the P-lead connection, the ignition controller also configured to selectively supply its own power.

An internal combustion engine for an aircraft can include a crankshaft configured to drive a propeller; a camshaft coupled to the crankshaft; and an ignition controller coupled to the camshaft and including a visual indicator, the visual indicator configured to produce a visual signal at a predetermined angular position of the engine. An ignition controller for an internal combustion engine can include a housing and a P-lead connection extending from the housing, the ignition controller configured to selectively supply or cut main electrical power from the engine via the P-lead connection, the ignition controller also configured to selectively supply its own power.

An ignition apparatus includes a plasma device, a first circuit, a second circuit, and a control unit. The plasma device produces a plasma discharge in an air-fuel mixture before an arc discharge is produced. The first circuit causes an ignition plug to start the arc discharge. The second circuit energizes a primary coil in a direction opposite to the direction of the energization by the first circuit during the arc discharge, to maintain energization of the secondary coil in the same direction as the direction of the energization started by an operation of the first circuit, to cause continuation of the arc discharge. The control unit controls operations of the first circuit, the second circuit, and the plasma device.

A system for monitoring and cleaning a spark plug is disclosed. In one example, rim firing of a spark plug is detected according to characteristics of a voltage of a primary coil of an ignition coil. The system may institute spark plug cleaning after rim firing of a spark plug is detected.