UNBURNED FUEL VENTING IN INTERNAL COMBUSTION ENGINES

摘要

An internal combustion engine is disclosed. The engine may have a cylinder. The engine may also have a piston reciprocally movable within the cylinder between a top dead center (TDC) and a bottom dead center (BDC). The piston may separate the cylinder into an upper piston section and a lower piston section. The piston may have a piston ring assembly with a piston ring configured to sealingly contact the cylinder. The piston ring assembly may have a thickness (D). The engine may have an annular crevice in fluid communication with the upper piston section. The engine may also have a plurality of venting grooves that may fluidly connect the annular crevice with the lower piston section, only when the crank angle ranges from about 85° to 95° and about 265° to 275° after the top dead center (TDC).

主权项

1. An internal combustion engine comprising:
a cylinder; a piston reciprocally movable within the cylinder between a top dead center (TDC) and a bottom dead center (BDC), the piston separating the cylinder into an upper piston section and a lower piston section, the piston including a piston ring assembly with at least one piston ring configured to sealingly contact the cylinder and having a piston ring assembly thickness (D); an annular crevice having an annular crevice volume and being in fluid communication with the upper piston section and being defined by the cylinder, the piston, and the piston ring assembly; and a plurality of venting grooves each extending within the cylinder in an axial direction over a length (L) greater than the piston ring assembly thickness (D), the venting grooves having a venting volume and being configured and positioned to fluidly connect the annular crevice with the lower piston section, only when the piston has a position corresponding to a crank angle range of about 85° to 95° and about 265° to 275° after the top dead center (TDC), the venting volume being within the range from 15% to 60% of the annular crevice volume.