If an engine coolant temperature is equal to or lower than a first low-temperature determination value and a battery temperature is equal to or lower than a second low-temperature determination value when a request to start up an engine is made, the advancement driving of a variable valve operating mechanism is first started. Then, when an advancement amount of the variable valve operating mechanism later becomes equal to or larger than a prescribed startup start determination value, is started.

An internal combustion includes: a camshaft having a metal core rod insert formed centrally in the camshaft and a driven gear, an exhaust cam, etc. formed of resin integrally with the camshaft; and a decompression mechanism. The decompression mechanism includes: a pair of supporting protrusions provided on the driven gear and each having an insertion hole; a decompression member having a pair of projections disposed between the supporting protrusions; and a biasing spring disposed between the projections for normally biasing the decompression member toward the exhaust cam. The camshaft also has a guide recess and a balancing recess formed in opposite sides of the camshaft, and the metal core rod is exposed through the guide recess and the balancing recess.

An internal combustion includes: a camshaft having a metal core rod insert formed centrally in the camshaft and a driven gear, an exhaust cam, etc. formed of resin integrally with the camshaft; and a decompression mechanism. The decompression mechanism includes: a pair of supporting protrusions provided on the driven gear and each having an insertion hole; a decompression member having a pair of projections disposed between the supporting protrusions; and a biasing spring disposed between the projections for normally biasing the decompression member toward the exhaust cam. The camshaft also has a guide recess and a balancing recess formed in opposite sides of the camshaft, and the metal core rod is exposed through the guide recess and the balancing recess.

A camshaft has a decompression device for an internal combustion engine, wherein a valve lifter is rotatably supported in a base circle of a cam, which can be brought into operative connection with a gas exchange valve via rotation. The valve lifter is operatively connected to a centrifugal fly weight, which is arranged coaxially to the camshaft and which is rotatably supported, in such a way that the valve lifter forms a contour of the base circle in the region of action with the gas exchange valve from a certain rotational speed of the camshaft. The camshaft has a cavity in the region of the centrifugal fly weight, to which cavity lubricant pressure can be applied. A radial first bore from the cavity to the centrifugal fly weight is arranged in the camshaft. A slideable element that can be displaced by the lubricant pressure is arranged in the first bore. By way of the design of the camshaft, an unstable centrifugal fly weight is stabilized and thus acoustics are improved.

A method for controlling a drivetrain of a motor vehicle is disclosed. Either a start mode for starting the reciprocating engine is activated via the driving vehicle wheel, or a coasting mode is activated for driving the reciprocating engine via the driving vehicle wheel. At least one volume-reducing stroke is executed that follows an intake stroke for at least one cylinder of the reciprocating engine with at least intermittently open cylinder. Alternately at least one volume-enlarging stroke is executed for at least one cylinder of the reciprocating engine, which is followed by a compression stroke of this cylinder, and at least one volume-reducing stroke of this cylinder, which follows an expansion stroke that follows the compression stroke, with a cylinder that is closed, if possible, in this operating mode.

A method for controlling a drivetrain of a motor vehicle is disclosed. Either a start mode for starting the reciprocating engine is activated via the driving vehicle wheel, or a coasting mode is activated for driving the reciprocating engine via the driving vehicle wheel. At least one volume-reducing stroke is executed that follows an intake stroke for at least one cylinder of the reciprocating engine with at least intermittently open cylinder. Alternately at least one volume-enlarging stroke is executed for at least one cylinder of the reciprocating engine, which is followed by a compression stroke of this cylinder, and at least one volume-reducing stroke of this cylinder, which follows an expansion stroke that follows the compression stroke, with a cylinder that is closed, if possible, in this operating mode.

Start-up of an internal combustion engine comprises maintaining one or more engine valves in an engine cylinder in a continuously open state for more than one engine cycle during engine cranking. When it is determined that an engine parameter or transmission oil pressure has reached a predetermined value, maintenance of the one or more engine valves in the continuously open state is discontinued and fuel is subsequently provided to the engine cylinder for engine start-up. In various embodiments, the engine parameter may comprise an engine temperature parameter, an engine pressure parameter or an engine electrical parameter.

Start-up of an internal combustion engine comprises maintaining one or more engine valves in an engine cylinder in a continuously open state for more than one engine cycle during engine cranking. When it is determined that an engine parameter or transmission oil pressure has reached a predetermined value, maintenance of the one or more engine valves in the continuously open state is discontinued and fuel is subsequently provided to the engine cylinder for engine start-up. In various embodiments, the engine parameter may comprise an engine temperature parameter, an engine pressure parameter or an engine electrical parameter.

A phase adjuster assembly configured to adjust a phase between a driving component and a driven component of an internal combustion engine is generally provided. The assembly includes an input gear assembly comprising an input gear configured to engage a driving component, and a spline carrier. An output gear assembly includes an output gear configured to engage a driven component, and a drive plate configured to drivingly engage with the spline carrier. Various components disclosed herein are formed as stamped sheet metal components. Additionally, various connections between adjacent components are provided via relative uncomplicated processes, such as welding.

A two-stroke, opposed-piston engine includes a cylinder with an inlet piston controlled inlet port and an exhaust piston controlled exhaust port, the cylinder defining a combustion chamber with the inlet piston and the exhaust piston, a charge air channel in flow communication with the inlet port, a conduit extending directly from the combustion chamber to the charge air channel, and a valve arranged to selectively open and close flow communication through the conduit.