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US 10,837,324 B2Granted
Four-stroke internal combustion engine thereto related vehicle and method
AssigneeScania CV AB
InventorsAndreas Dahl, Eric Olofsson
Life of this patent
Estimating the term…
Abstract
A four-stroke internal combustion engine is disclosed. A camshaft and a crankshaft if the engine are synchronised to rotate at a same rotational speed. A first linkage arrangement is configured to change the motion of an exhaust valve head. A second linkage arrangement is configured to change the motion of the intake valve head. A control unit is configured for controlling the first linkage arrangement to selectively prevent or reduce the motion of the exhaust valve head and for controlling the second linkage arrangement to selectively prevent or reduce the motion of the intake valve head.
Claims19
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, and a connecting rod connecting the piston to the crankshaft;
- an exhaust arrangement comprising 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;
- and
- at least one camshaft comprising:
- a first lobe configured to cause a motion of the exhaust valve head, so as to open and close the exhaust opening, via a first linkage arrangement;
- and a second lobe configured to cause a motion of the intake valve head, so as to open and close the intake opening, via a second linkage arrangement,
- wherein the at least one camshaft is synchronized with the crankshaft to rotate at a same rotational speed as the crankshaft,
- wherein the piston performs a four stroke operation in the cylinder bore, corresponding to an intake stroke, a compression stroke, a power stroke, and an exhaust stroke,
- wherein the first linkage arrangement is configured to change the motion of the exhaust valve head by selectively switching between an activated lift, a partial lift, and a deactivated lift of the exhaust valve head,
- wherein the second linkage arrangement is configured to change the motion of the intake valve head by selectively switching between an activated lift, a partial lift, and a deactivated lift of the intake valve head,
- wherein the partial lift of the exhaust valve head opens the exhaust opening to a lesser degree than the activated lift of the exhaust valve head,
- wherein the partial lift of the intake valve head opens the intake opening to a lesser degree than the activated lift of the intake valve head,
- wherein the first linkage arrangement and the second linkage arrangement are controlled by a control unit, and
- wherein the control unit in a first engine braking mode is configured to switch the first linkage arrangement to the deactivated lift of the exhaust valve head at every rotation or every alternate rotation of the at least one camshaft such that the exhaust opening remains closed during the compression stroke and/or during the exhaust stroke, and either:
- switch the second linkage arrangement to the partial lift of the intake valve head during the intake stroke and the power stroke, or
- switch the second linkage arrangement to the deactivated lift of the intake valve head at every alternate rotation of the at least one camshaft such that the intake opening remains closed during the intake stroke or the power stroke, and to switch to the partial lift of the intake valve head such that the intake opening is partially opened during a remaining one of the intake stroke and the power stroke.
15 more elements
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 comprises a cylinder bore, a piston arranged to reciprocate in the cylinder bore, and a connecting rod connecting the piston to the crankshaft;
- an exhaust arrangement comprising 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;
- and
- at least one camshaft comprising:
- a first lobe configured to cause a motion of the exhaust valve head, so as to open and close the exhaust opening, via a first linkage arrangement, and a second lobe configured to cause a motion of the intake valve head, so as to open and close the intake opening, via a second linkage arrangement,
- wherein the piston performs a four stroke operation in the cylinder bore, corresponding to an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, and wherein the method comprising:
- rotating the at least one camshaft at a same rotational speed as the crankshaft;
- changing the motion of the exhaust valve head by selectively switching the first linkage arrangement between an activated lift, a partial lift, and a deactivated lift of the exhaust valve head;
- changing the motion of the intake valve head by selectively switching the second linkage arrangement between an activated lift, a partial lift, and a deactivated lift of the intake valve head;
- wherein the partial lift of the exhaust valve head opens the exhaust opening to a lesser degree than the activated lift of the exhaust valve head;
- wherein the partial lift of the intake valve head opens the intake opening to a lesser degree than the activated lift of the intake valve head;
- and
- wherein in a first engine braking mode the method further comprises switching the first linkage arrangement to the deactivated lift of the exhaust valve head at every rotation or every alternate rotation of the at least one camshaft such that the exhaust opening remains closed during the compression stroke and/or during the exhaust stroke, and either:
- switching the second linkage arrangement to the partial lift of the intake valve head such that the intake opening is partially opened during the intake stroke and the power stroke;
- or
- switching the second linkage arrangement to the deactivated lift of the intake valve head at every alternate rotation of the at least one camshaft such that the intake opening remains closed during the intake stroke or the power stroke, and switching to the partial lift of the intake valve head such that the intake opening is partially opened during a remaining one of the intake stroke and the power stroke.
15 more elements
Dependencies are inferred from the claim text.