The effect of different engine operating conditions and piston pin hole offset parameters on piston friction and wear was compared by the engine bench test and piston dynamical simulation. Results show that the sensitivity of the contact pressure on diesel engine piston to the piston pin hole offset is higher than that of gasoline engine piston. Smaller offset will often make the piston skirt produced larger. With the increase of pin hole offset

the maximum contact pressure on piston skirt will gradually reduce

but when it increases to a certain degree

the maximum contact pressure will have a reverse trend to increase. The cumulative wear load growth of piston skirt main thrust side occurs mainly in the first half of the power stroke

almost no increase in the exhaust stroke and intake stroke. The cumulative wear load growth of piston skirt secondary thrust side occurs mainly in the middle of the exhaust stroke

but almost no increase in the intake stroke. The change of pin hole center leads to the change of piston mass center

which will change the engine related performance. By optimizing the pin hole offset of the gasoline engine

the wear load on the piston skirt thrust side is changed from 27.46 MW/m2 to 1.12 MW/m2

which is almost 25 times compared with the original one. This simulation can solve the problem of piston skirt wear

and the results agree with the experimental date very well.