These three kinds of shapes were tested to examine the influence of the oil groove on the spread of the cylinder oil through the comparison between 1] and 2], and to examine the difference between the wave cut and the honing through the comparison between 1] and 2].
2.2 Shape of ring running surface
The barrel shape of 5 (m in projecting quantity of the ring running surface as illustrated in Fig.3 is defined as the reference shape, and compared with the plain shape.
2.3 Kind of cylinder oil and liner temperature
In order to set the viscosity of the lubricating oil in the test to be equivalent to the viscosity of the cylinder oil of the actual engine (the kinematic viscosity of 3.0 cSt at the liner TDC temperature of 210℃ with the oil kind SAE 50), the kinematic viscosity is set to 2.4 cSt at the liner temperature of 30℃ with ISO VG2 lubricating oil.
2.4 Oil-feed quantity
With reference to the oil quantity per rotation of the engine and per unit running area with the oil-feed ratio of 1 g/PS･hr in the actual engine, the reference oil-feed quantity is set to 0.02 cc/ome feed (one oil feed with 5 rotation of the tester), and comparison was made with the oil-feed quantity of 0.01 cc/ome feed and 0.03 cc/ome feed.
