Four-stroke internal combustion engine thereto related vehicle and method

A vehicle comprising a four-stroke internal combustion engine comprising:

• a crankshaft;
• at least one cylinder arrangement forming a combustion chamber and comprising a cylinder bore, a piston arranged to reciprocate in the cylinder bore, a connecting rod connecting the piston with the crankshaft;
• an exhaust arrangement for outflow of exhaust gas from the cylinder bore,
• wherein the exhaust arrangement comprises an exhaust valve, an exhaust opening, and an exhaust valve head configured to seal against an exhaust valve seat of the exhaust opening;
• an intake arrangement for intake of fresh gas into the cylinder bore, wherein the piston performs four-strokes in the cylinder bore, corresponding to an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, wherein the intake arrangement comprises an intake valve and an intake opening, the intake valve comprising an intake valve head configured to seal against an intake valve seat of the intake opening;
• at last one camshaft comprises a first lobe configured to cause a motion of the exhaust valve head for opening and closing the exhaust opening, and a second lobe configured to cause a motion of the intake valve head for opening and closing the intake opening, wherein the at least one camshaft is synchronized with the crankshaft to rotate at a same rotational speed as the crankshaft,
• wherein the exhaust arrangement comprises a first linkage arrangement configured to change the motion of the exhaust valve head caused by the first lobe, and the intake arrangement comprises a second linkage arrangement configured to change the motion of the intake valve head caused by the second lobe;
• and
• a control unit configured for controlling the first linkage arrangement to selectively prevent the motion of the exhaust valve head and configured for controlling the second linkage arrangement to selectively prevent the motion of the intake valve head.

A method for controlling a four-stroke internal combustion engine, the four-stroke internal combustion engine comprising:

• a crankshaft;
• at least one cylinder arrangement forming a combustion chamber and comprising a cylinder bore, a piston arranged to reciprocate in the cylinder bore, a connecting rod connecting the piston with the crankshaft, an exhaust arrangement for outflow of exhaust gas from the cylinder bore, and an intake arrangement for intake of fresh gas into the cylinder bore, wherein the piston performs four-strokes in the cylinder bore, corresponding to an intake stroke, a compression stroke, a power stroke, and an exhaust stroke;
• an exhaust arrangement comprises an exhaust valve and an exhaust opening, the exhaust valve comprising an exhaust valve head configured to seal against an exhaust valve seat of the exhaust opening;
• an intake arrangement comprising an intake valve and an intake opening, the intake valve comprising an intake valve head configured to seal against an intake valve seat of the intake opening;
• at least one camshaft comprising a first lobe configured to cause a motion of the exhaust valve head for opening and closing the exhaust opening, and the at least one camshaft comprising a second lobe configured to cause a motion of the intake valve head for opening and closing the intake opening,
• wherein the method comprises:
• rotating the at least one camshaft at a same rotational speed as the crankshaft;
• changing the motion of the exhaust valve head caused by the first lobe by means of a first linkage arrangement comprised in the exhaust arrangement;
• and
• changing the motion of the intake valve head caused by the second lobe by means of a second linkage arrangement comprised in the intake arrangement,
• wherein changing the motion of the exhaust valve head comprises:
• selectively preventing the motion of the exhaust valve head by means of the first linkage arrangement,
• wherein changing the motion of the intake valve head comprises:
• selectively preventing the motion of the intake valve head by means of the second linkage arrangement,
• wherein the cylinder arrangement is configured to drive the crankshaft in a four-stroke engine running mode only, wherein in the four-stroke engine running mode, wherein selectively preventing the motion of the exhaust valve head comprises:
• preventing the motion of the exhaust valve head otherwise caused by the first lobe at every alternate rotation of the at least one camshaft, such that the exhaust opening remains closed during the compression stroke, and
• wherein selectively preventing the motion of the intake valve head comprises:
• preventing the motion of the intake valve head otherwise caused by the second lobe at every alternate rotation of the at least one camshaft such that the intake opening remains closed during the power stroke.

A computer program product comprising computer program code stored on a non-transitory computer-readable medium, said computer program product used for controlling a four-stroke internal combustion engine, wherein the combustion engine comprises:

• a crankshaft;
• at least one cylinder arrangement forming a combustion chamber and comprising a cylinder bore, a piston arranged to reciprocate in the cylinder bore, a connecting rod connecting the piston with the crankshaft, an exhaust arrangement for outflow of exhaust gas from the cylinder bore, and an intake arrangement for intake of fresh gas into the cylinder bore, wherein the piston performs four-strokes in the cylinder bore, corresponding to an intake stroke, a compression stroke, a power stroke, and an exhaust stroke;
• an exhaust arrangement comprises an exhaust valve and an exhaust opening, the exhaust valve comprising an exhaust valve head configured to seal against an exhaust valve seat of the exhaust opening;
• an intake arrangement comprising an intake valve and an intake opening, the intake valve comprising an intake valve head configured to seal against an intake valve seat of the intake opening;
• at least one camshaft comprising a first lobe configured to cause a motion of the exhaust valve head for opening and closing the exhaust opening, and the at least one camshaft comprising a second lobe configured to cause a motion of the intake valve head for opening and closing the intake opening, said computer program code comprising computer instructions to cause one or more control units to perform the operations of:
• rotating the at least one camshaft at a same rotational speed as the crankshaft;
• changing the motion of the exhaust valve head caused by the first lobe by means of a first linkage arrangement comprised in the exhaust arrangement;
• and
• changing the motion of the intake valve head caused by the second lobe by means of a second linkage arrangement comprised in the intake arrangement,
• wherein changing the motion of the exhaust valve head comprises:
• selectively preventing the motion of the exhaust valve head by means of the first linkage arrangement,
• wherein changing the motion of the intake valve head comprises:
• selectively preventing the motion of the intake valve head by means of the second linkage arrangement,
• wherein the cylinder arrangement is configured to drive the crankshaft in a four-stroke engine running mode only, wherein in the four-stroke engine running mode, wherein selectively preventing the motion of the exhaust valve head comprises:
• preventing the motion of the exhaust valve head otherwise caused by the first lobe at every alternate rotation of the at least one camshaft, such that the exhaust opening remains closed during the compression stroke, and
• wherein selectively preventing the motion of the intake valve head comprises:
• preventing the motion of the intake valve head otherwise caused by the second lobe at every alternate rotation of the at least one camshaft such that the intake opening remains closed during the power stroke.