Camshaft with low lift dwell profile and methods for operating the same
AssigneeCummins Inc.
InventorsThomas Robert Marsh, Vaibhav J. Lawand, Brendan J. O'Grady
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Abstract
Systems, apparatus, and methods are disclosed that include an internal combustion engine having a plurality of cylinders and at least one camshaft for opening at least one valve associated with the at least one cylinder. The camshaft includes a cam with a cam lobe defining a cam lobe profile having a base circle portion on a base circle of the cam lobe, a main cam lobe portion, and a low lift dwell portion that extends a constant height from the base circle along a substantial portion of the base circle to increase valve opening overlap and cylinder scavenging.
Claims10
A camshaft arrangement for opening a valve of an engine, comprising:
- a cam defining a cam lobe profile that consists of a base circle portion on a base circle of the cam lobe, a low lift dwell portion, and a main cam lobe portion, wherein:
- the low lift dwell portion extends a first height from the base circle and the first height is constant along the low lift dwell portion, wherein the first height defines the maximum height of the cam profile other than at the main cam lobe portion, and the low lift dwell portion is configured so that the valve is lifted from a seat by a distance corresponding to the first height that is sufficient for scavenging during an engine cycle and the valve is maintained at the distance along the entire low lift dwell portion;
- and
- the main cam lobe portion lies adjacent to the low lift dwell portion and extends a second height above the base circle portion at an apex of the main cam lobe portion to fully lift the valve from the seat during the engine cycle.
Dependencies are inferred from the claim text.