Design of parameters for running-in cylinder liner piston rings based on running-in attractor

Friction and wear is one of the important energy losses of cylinder liner piston rings (CLPRs). The research on the design of running in test parameters of cylinder liner and piston ring is of great significance to reduce the energy loss of internal combustion engine and improve the service life. In order to shorten the running-in time and improve the running-in quality of CLPR, the running-in tests were carried out and running-in parameters of CLPR were designed based on running-in attractor theory. The running-in tests of CLPR samples were carried out for 28 groups under different speed and load conditions, and the friction signal and the running-in surface morphology were collected. The running-in attractor phase trajectory is constructed from the friction signal time series, and the characteristic parameters of the running-in attractor are calculated. The running-in state and time under different working conditions are identified by the evolution law of the running-in attractor phase trajectory and chaotic characteristic quantities. The running-in quality under different working conditions is obtained by the fractal dimension of the surface morphology and characteristic roughness parameters. The running-in parameters of CLPR aiming at both short running-in time and improve running-in quality are designed, and a multi index optimization design aiming at short running-in time and good running-in quality is carried out. The results show that an optimal solution for the CLPR running-in tests under different objectives does existed, and the corresponding optimal running-in parameters are obtained. These parameters, in turn, guide the choice of optimal working conditions. This work can provide ideas for the study of other friction pairs.