Deformation characteristics of diesel engine cylinder liner under pre-tightening condition

For effectively suppressing seal failure caused by deformation of cylinder liner in high power diesel engine, the out-of-roundness and Fourier spectrum analysis of the cross section of cylinder liner inner surface were applied as liner deformation evaluation indexs. The cylinder liner deformation characteristics were analyzed under the pre-tightening condition of a composite model with cylinder, cylinder head, cylinder liner. The influence laws of pre-tightening force of head bolts, sink hole depth of head bolts and distribution locations of head bolts on cylinder liner deformation have been studied and compared with test results. The results show that: under the pre-tightening condition, the cylinder liner presents elliptical deformation at the upper cross-sections and small deformation at the lower position; with the increase of bolt pre-tightening force, whole cylinder liner deformation increases; and then, when the depth of bolt sink hole increases, the second order Fourier deformation of cylinder liner increases, the fourth order decreases;moreover, the increase of the angle between the line of diagonal bolts and the center line of inlet and outlet could reduce the deformation of cylinder liner significantly.