| 摘要 |
A machine comprising a cylinder (103) and a piston ring set for a piston (109) of the machine, the piston ring set comprising a first piston ring (207) having a first profile and a second piston ring (207) having a second profile, the first and second profiles being different, each of the piston rings (207) having a circumferential surface (217) configured to engage an inner surface (105) of the cylinder (103), the inner surface (105) having at least one recess (129) indented into the inner surface (105), the engagement of a contact portion of the circumferential surface (217) of each of the piston rings (207) with the inner surface (105) of the cylinder (103) defining respective contact zones (111) therebetween, the remainder of the circumferential surface (217) of each piston ring (207) not engaging the inner surface (105), wherein the contact portion of the circumferential surface (217) of each of the piston rings (207) is configured such that the ratio of the dimension of each contact zone (211) in the direction of travel of the piston (109) to the dimension of the recess (129) in the direction of travel of the piston (109) is in the range of approximately 5:1 to 5:3. |
