Camshaft profile for reducing cylinder pressures during engine cranking

摘要

A camshaft assembly may include a shaft and a lobe member fixed for rotation with the shaft. The lobe member may include a lobe extending radially outward from a base circle. The lobe may include a valve closing profile defined between a peak of the lobe and an ending point of the lobe on the base circle. The valve closing profile may define a closing flank and a closing ramp extending from an end of the closing flank to the ending point. The closing ramp may have a radial extent from the base circle at the end of the closing flank that is less than ten percent of the radial extent of the peak from the base circle and may have a first angular extent of at least ten degrees. A second angular extent defined between the peak and the ending point may be at least eighty degrees.