The piston may be connected to the upper end of the connecting rod either directly (trunk piston type), or indirectly (crosshead type).
活塞与连杆上端的连接，既可以是直接连接(筒状活塞式)，也可以是间接连接(十字头式)。
2
Upper and lower piston rings are arranged inside a piston gaseous ring groove, and openings on the two-piece piston rings are mutually staggered.
在一个活塞气环槽内设有上下二片活塞环，二片活塞环上的开口相互错开。
3
In trunk-piston engines, a horizontal pin within the piston is encircled by the upper end of the connecting rod. This by far the most common construction.