An exhaust valve system for a two-stroke internal combustion engine having: at least one exhaust valve movable between open and closed positions; an actuator for moving the at least one exhaust valve; a valve position sensor; a controller communicating with the actuator and the valve position sensor. The controller being programmed for: controlling the actuator to attempt to move the at least one exhaust valve to a desired one of the open and closed positions; determining if the at least one exhaust valve has failed to reach the desired position based on the position of the at least one exhaust valve sensed by the valve position sensor; and controlling the actuator to move the at least one exhaust valve to an intermediate position when the at least one exhaust valve has failed to reach the desired position.

An internal combustion engine system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system to provide air to the plurality of cylinders through respective ones of a plurality of intake valves, an exhaust system to release exhaust gas from the plurality of cylinders through respective one of a plurality of exhaust valves. A valve train is provided for cylinder deactivation of a first part of the plurality of cylinders and compression release braking on a second part of the plurality of cylinders.

The invention pertains to gas exchange in internal combustion engines using low to zero-emission fuels. The combustion engine has the ability to regulate the quantity of air/fuel mixture in the cylinder using one or more exhaust valve(s) (2) that can have adjustable opening times in order to control the gas exchange in the cylinder so that exhaust and alternatively also air can be expelled into the exhaust system. By reducing the quantity of air and thus the quantity of fuel for each cycle, that combined with reduced compression pressure means that engines can operate with a higher expansion ratio by leaving the exhaust valve(s) (2) open through a part of the compression stroke to reduce the amount of air to the combustion and reduce compression and then pressure rise before combustion. Air volume and gas exchange are regulated by compressor(s) (5) as well as opening and closing of exhaust valve(s) (2) with the exhaust valve control (4); alternatively, also intake valves for 4-stroke engines.

A closing fork and open spring bias of a center power valve for a hitless control of an adjustable exhaust port 2-stroke motorcycle engine includes a closing fork which includes a flat plate that extends into two substantially parallel flat closing fork arms. An internal closing fork base section cylindrical wall accepts a shaft inserted there through. Each torsion spring of two torsion springs has a first extended leg including an approximately 90-degree bend about where the first extended leg extends out from a spring body of each torsion spring and a second leg extending straight out of a body of each torsion spring. Each of the torsion springs is a mirror of each other where the first extended leg extends from a different side. An upgrade kit and a method to convert a power valve system 2-stroke motorcycle engine to a hitless operation are also described.

Systems and methods are provided for operating an internal combustion engine in a two-stroke mode or a four-stroke mode to achieve greater fuel efficiency and minimize emissions. The system comprises a mode-adaptable valve; a valve rocker arm to actuate opening and closing of the mode adaptable valve; a cam follower of a first cam for carrying out a two-stroke mode; a cam follower of a second cam for carrying out a four-stroke mode; and a pin to mechanically couple the valve rocker arm to the cam follower of the first cam or the cam follower of the second cam. Coupling the valve rocker arm to the cam follower of the first cam enables a two-stroke mode and coupling the valve rocker arm to the cam follower of the second cam enables a four-stroke mode.

Systems and methods are provided for operating an internal combustion engine in a two-stroke mode or a four-stroke mode to achieve greater fuel efficiency and minimize emissions. The system comprises a mode-adaptable valve; a valve rocker arm to actuate opening and closing of the mode adaptable valve; a cam follower of a first cam for carrying out a two-stroke mode; a cam follower of a second cam for carrying out a four-stroke mode; and a pin to mechanically couple the valve rocker arm to the cam follower of the first cam or the cam follower of the second cam. Coupling the valve rocker arm to the cam follower of the first cam enables a two-stroke mode and coupling the valve rocker arm to the cam follower of the second cam enables a four-stroke mode.

A rotational combustion engine that generates force from the reciprocal motion and centripetal motion of one or more pistons that is then converted into rotational motion of a first cam and second cam wherein the cams are separated by a 2-3 degree horizontal offset and an angle of 60 degrees as well as camshaft assembly and driving shaft to provide power to an entity such as an automobile.

An exhaust valve assembly for a two-stroke internal combustion engine has a valve actuator, and a two-part valve having a primary and secondary valves defining first and second decompression passages respectively. The primary valve is operatively connected to the valve actuator. The primary valve is in first, second and third primary valve positions when the valve actuator is in first, second and third actuator positions respectively. The secondary valve is in a first secondary valve position when the valve actuator is in the first or the second actuator position and in a second secondary valve position when the valve actuator is in the third actuator position. The first and second valve decompression passages fluidly communicate with each other when the valve actuator is in the second actuator position, and are fluidly separate from each other when the valve actuator is the first or the third actuator position.

The present invention concerns a method and a device for electrically controlling a valve actuator in a two-stroke or four-stroke combustion engine where the actuator comprises a solenoid (A), a plunger (5) and a spring (6), wherein the engine has at least one cylinder (1) with at least one freely controllable engine valve disc (10) with corresponding valve stem (11) and a valve spring (4), where a distance (7) is provided between the lower end of the plunger and the upper end of the valve stem and where air is supplied, or exhaust gases are evacuated from, a combustion chamber (3) past a lower part of the valve stem with the valve disc via at least one channel (2) in the cylinder, wherein the valve actuator is activatable to open the engine valve. The invention is characterized in that the opening of the engine valve is initiated after activation of the solenoid, wherein the following acceleration of the plunger brings its lower end to strike the upper end of the valve stem for initial opening of the valve.

The present invention concerns a method and a device for electrically controlling a valve actuator in a two-stroke or four-stroke combustion engine where the actuator comprises a solenoid (A), a plunger (5) and a spring (6), wherein the engine has at least one cylinder (1) with at least one freely controllable engine valve disc (10) with corresponding valve stem (11) and a valve spring (4), where a distance (7) is provided between the lower end of the plunger and the upper end of the valve stem and where air is supplied, or exhaust gases are evacuated from, a combustion chamber (3) past a lower part of the valve stem with the valve disc via at least one channel (2) in the cylinder, wherein the valve actuator is activatable to open the engine valve. The invention is characterized in that the opening of the engine valve is initiated after activation of the solenoid, wherein the following acceleration of the plunger brings its lower end to strike the upper end of the valve stem for initial opening of the valve.