Piston rotation and frictional forces between piston and cylinder of piston and motor

Figure 1 shows the scheme of measurement parts of the rotational speeds of the piston and the frictional forces between the piston and the cylinder. The principal parts are the same as that

measured the frictional forces and the oil film thickness by Kyogoku et al. (1),(2). The specification of the piston and the cylinder is shown in Table 1.