Influence of Piston Ring End Gap Position on Blow-by

In order to reduce blow-by through piston ring-pack without changing geometry parameters of piston and rings, a blow-by flow model was established. The blow-by in 1 800 r/min full load conditions was calculated firstly in this study. Then the positions of end gap were optimized based on orthogonal design. The gas flow through end gap, groove, and running face was calculated and analyzed separately. Results show that the optimization scheme can reduce the blow-by by 10.3% compared to original scheme. And the reason that the higher blow-by produces in original scheme was analyzed. It is mainly due to the oil ring flutter caused by piston land pressure. Gas flow was greatly influenced by land pressure in all the three flow channels. Blow-by can be reduced effectively by reasonable adjustment of end gap and rational allocation of land pressure. The state of oil ring can influence the blow-by indirectly by changing the land pressure.