Research On Friction Properties Of Piston Ring And Cylinder Liner In Internal Combustion Engine Under Cold-starting State

The requirement of the working environment for vehicles is more and more critical.Internal combustion engines, as the heart of the vehicle, also have to develop with the trend ofhigh power, high speed, high efficiency, good starting performance, low noise and lowemission. Piston ring and cylinder liner is an important friction pair in the internal combustionengine. In cold-starting condition, as the environment temperature is very low, the piston ringhas to bear the interaction of the piston reciprocating inertia force and the impact of highpressure and temperature of the combustion gas. The tribological properties of the piston ringand cylinder liner will be deteriorated in lower temperature, and so will the lubricationquality.In this article, temperature is chosen as the main variable. The tribological properties andlubrication performances of the piston ring and cylinder liner will be studied in the progress ofgradually temperature decreases. The results will provide a series of theoretical basis andsimulation methods for the prediction of tribological properties in the piston ring-cylinderliner friction pair, also for further design work of internal combustion engines in lowtemperature.In this article, the mainly studied contents are as follows.(1) Deduction of the mathematical model for piston ring-cylinder linerAn internal combustion engine was taken as the object for the research work. Thekinematic analysis was conducted for the piston. The dynamics model was established for the first ring in the cylinder. The mathematical model for piston ring-cylinder linerwas deducted.(2) Analysis of the impact on the friction properties with temperature changeThe parameters were analyzed with temperature changes for the friction model. Thevariation curves were obtained for each parameter when the temperature drops. Then thefriction force was calculated at particular temperatures for the piston ring-cylinder linerduring the first combustion cycle with the help of this model.(3) Verification for the friction modelThe simulation for the piston ring-cylinder liner model was conducted by means ofRicardo-Ringpak software. The friction force and friction power loss on the first ringduring first combustion cycle was obtained at variety of temperatures. The phenomenonwhich friction force increases with decreasing temperature was explained using asperitycontact theory.