Piston for internal combustion engine has outer second trough sector defined by elliptical shape in cross section

摘要

The piston (10) has its outer second trough sector (20) defined by an elliptical or droplet shape in cross section; or the transition (22) between the inner first trough sector (18) and the outer second trough sector is of shallower depth (T3) from the endface (16) facing the piston than the outer second trough sector itself.