| 摘要 |
<p>A fuel pump for use in an internal combustion engine has a pumping plunger (37) for pressurising fuel within a pump chamber (36) during a plunger pumping stroke and a drive member (20), such as a tappet, for imparting axial drive to the pumping plunger (37) to perform its plunger pumping stroke. The drive member (20) is movable within a drive member bore (38) having a drive bore axis and a shaft-driven cam (14) co-operates with the drive member (20). The cam (14) has a first axis of rotation (16) and the drive shaft has a second axis of rotation (12) displaced from the first axis of rotation, the first and second axes of rotation (12, 16) being offset from one another to define a pump eccentricity. The drive bore axis (38) is displaced relative to the second axis of rotation (12) by an offset amount, the offset amount being selected to be that amount at which the difference in energy absorbed at regions (120b, 220b, 120c, 220c) of contact between the drive member (20) and the drive member bore (38) as the drive member experiences torque, in use, is substantially minimised.</p> |
