4.2　Structure of the main part

　

4.2.1　Cylinder block

The cylinder block is adopted cast iron underslung main bearing and is a box type unit structure which integrates the cam chamber, air inlet duct, cooling water distributing pipes and lubrication oil main gallery. Besides high rigidity, it has less outer piping which makes maintenance and inspection easier. When design is made on the cylinder block, structural analysis by means of three-dimensional FEM model is executed to seek optimization for the wall thickness and rib arrangement. As sufficient rigidity is given under high combustion pressure while designing light weight, vibration and noise is reduced.

FEM model

Fig　6

Deformation of Cylinder Block(by FEM Analysis)

Table　6

Fig　7

4.2.2　Cylinder liner

The cylinder liner is made of special cast iron which is rich in wear and abrasion resistance, and the wall thickness is made thicker to bear high combustion pressure and to prevent cavitation by means of piston slap. The inside is given nitriding treatment and platoon honing to reduce wear of liner and piston ring. The upper part of the liner is equipped with anti-polishing ring to control temperature rise of the upper part of liner and also to control hard carbon deposit on the piston top land, thus lubrication consumption is reduced.

Fig　8

Lower part periphery of the cylinder liner collar is given forced cooling to reduce thermal load of the cylinder liner and the peripheral jacket part is cooled uniformly by means of swivel current.

Structural analysis is carried out in the state that cylinder liner, cylinder block and cylinder head are assembled, and stress concentration of R part below collar of cylinder liner is reduced and optimum of the liner temperature is designed.

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