Influence of pin assembly on the wear behavior of piston skirt

Different pinhole offset and assembly clearance between pin and pinhole were designed to investigate the influence on wear behavior of piston skirt. The pistons with different pin assemblies were fabricated and assembled in the same engines. The engine tests were conducted under standard condition. The wear of piston skirt was focused to evaluate the effects of different pin assemblies. Micro-observations were conducted to investigate the wear degrees of worn skirts. Numerical simulation method was introduced to analyze the different wear mechanisms under different pin assemblies. Results show that the pinhole offset and assembly clearance both influenced the skirt wear behavior obviously. None or too small negative offset resulted in obvious noise during engine worked. Too larger negative offset resulted in severe wear. Larger assembly clearance under rational scope improves the stability of secondary motion of piston. Additionally, wear degrees on thrust side were obvious lager than anti-thrust side. The higher contact pressure on piston skirt in expansion stroke was the main reason.