A non-road high-pressure common rail diesel engine was taken as the research object. Based on the result of piston temperature field test

a piston dynamic model was established. The influence of different cylinder clearances and piston ring end gap chamfers on diesel engine blow-by and oil consumption was emphatically studied. The response surface method was used to analyze the influence of the piston ring end gap on blow-by. Based on the result

optimize the end gap of top ring and the second ring to obtain the optimal solution. The results indicate that

oil consumption increases with the increase of the cylinder clearances

and the largest increase is 7.54%. Cylinder clearance has little effect on the blow-by while piston ring end gap chamfer has significant influence on blow-by. Blow-by increased 13% when top ring end gap chamfer increased from 0 to 1mm. The end gap of the top ring and the second ring has a significant linear relationship with the blow-by while the end gap of oil ring has little influence on blow-by. The optimal solution appears when the end gap of top ring is 0.42mm and the end gap of second ring is 0.48mm. At this moment

the blow-by is 13.11L/min.