A camshaft includes, as a cam that opens and closes an exhaust valve and an intake valve, a ball cam whose protrusion amount changes according to rotation of the camshaft, wherein the camshaft has a double structure consisting of an inner shaft and an outer shaft provided in a manner that the inner shaft is helically displaced with respect to the outer shaft around an axis of the camshaft according to a rotation speed of the camshaft, and the ball cam is accommodated movably in a guide groove provided in the inner shaft and protrudes from the outer shaft, and a protrusion amount of the ball cam from the outer shaft changes when the ball cam moves in the guide groove due to the helical displacement of the inner shaft with respect to the outer shaft.

In an exemplary embodiment, an internal combustion engine, in which a valve is opened and closed when a piston reciprocates in a cylinder, has a configuration to perform repeatedly the following combined strokes: an intake stroke.fwdarw.a compression stroke.fwdarw.a combustion stroke.fwdarw.an exhaust stroke in a four-cycle internal combustion engine are combined with an intake and compression stroke.fwdarw.a combustion and exhaust stroke in a two-cycle internal combustion engine. The internal combustion engine can reduce pumping loss in a six-cycle internal combustion engine and increase the output.

A camshaft includes, as a cam that opens and closes an exhaust valve and an intake valve, a ball cam whose protrusion amount changes according to rotation of the camshaft, wherein the camshaft has a double structure consisting of an inner shaft and an outer shaft provided in a manner that the inner shaft is helically displaced with respect to the outer shaft around an axis of the camshaft according to a rotation speed of the camshaft, and the ball cam is accommodated movably in a guide groove provided in the inner shaft and protrudes from the outer shaft, and a protrusion amount of the ball cam from the outer shaft changes when the ball cam moves in the guide groove due to the helical displacement of the inner shaft with respect to the outer shaft.

A two-stroke combustion engine comprising a user-operated throttle control, an adjustable valve arranged to control one or more air intakes of the combustion engine, and a control unit arranged to control a state of the adjustable valve, wherein the combustion engine is arranged to operate in a first idle mode at an idle engine speed below a clutch engagement engine speed when the user-operated throttle control is not engaged, wherein the combustion engine is arranged to operate in a second idle mode at a target engine speed above the clutch engagement engine speed when the user-operated throttle control is engaged and when the engine is not subject to an external load, the control unit being arranged to control the state of the adjustable valve to maintain engine speed at the target engine speed when the engine operates in the second idle mode.

The present disclosure relates to a 2-cycle engine with a valve system that generates power during every one crankshaft rotation. The 2-cycle engine of the present disclosure includes the valve system opening and closing an air intake valve and an exhaust valve and includes a turbocharger. In the turbocharger, the air intake valve and the exhaust valve are respectively opened and closed once during one crankshaft rotation, and the valve system is configured to control the turbocharger using difference between an air intake pressure and an exhaust pressure. Accordingly, a current air intake reaches a target air intake.

The present disclosure relates to a 2-cycle engine with a valve system that generates power during every one crankshaft rotation. The 2-cycle engine of the present disclosure includes the valve system opening and closing an air intake valve and an exhaust valve and includes a turbocharger. In the turbocharger, the air intake valve and the exhaust valve are respectively opened and closed once during one crankshaft rotation, and the valve system is configured to control the turbocharger using difference between an air intake pressure and an exhaust pressure. Accordingly, a current air intake reaches a target air intake.

In an exemplary embodiment, an internal combustion engine, in which a valve is opened and closed when a piston reciprocates in a cylinder, has a configuration to perform repeatedly the following combined strokes: an intake stroke.fwdarw.a compression stroke.fwdarw.a combustion stroke.fwdarw.an exhaust stroke in a four-cycle internal combustion engine are combined with an intake and compression stroke.fwdarw.a combustion and exhaust stroke in a two-cycle internal combustion engine. The internal combustion engine can reduce pumping loss in a six-cycle internal combustion engine and increase the output.

Disclosed is a complementary analog and digital method for controlling ignition of a gasoline engine. First, analog ignition is performed by means of an analog trigger circuit. After power has been steadily supplied to a microcontroller, the microcontroller disconnects the analog trigger circuit, starts to collect a digital trigger reference signal and turn on a digital trigger circuit, and switches to a digital signal to trigger ignition. Also disclosed is a complementary analog and digital system for controlling ignition of a gasoline engine.

Disclosed is a complementary analog and digital method for controlling ignition of a gasoline engine. First, analog ignition is performed by means of an analog trigger circuit. After power has been steadily supplied to a microcontroller, the microcontroller disconnects the analog trigger circuit, starts to collect a digital trigger reference signal and turn on a digital trigger circuit, and switches to a digital signal to trigger ignition. Also disclosed is a complementary analog and digital system for controlling ignition of a gasoline engine.

The present disclosure relates to a 2-cycle engine with a valve system that generates power during every one crankshaft rotation. The 2-cycle engine of the present disclosure includes the valve system opening and closing an air intake valve and an exhaust valve and includes a turbocharger. In the turbocharger, the air intake valve and the exhaust valve are respectively opened and closed once during one crankshaft rotation, and the valve system is configured to control the turbocharger using difference between an air intake pressure and an exhaust pressure. Accordingly, a current air intake reaches a target air intake.