Research on Design Development and Modification of a Steel Piston in a Heavy-Duty Diesel Engine

The thermal and mechanical loads of the engine rise dramatically with the increase in engine power density, which places higher demands on the design of the piston. In this paper, the design development of a steel piston for a marine diesel engine belonging to 190 series heavy-duty diesel engines was studied. The design methods including material selection and structural design were used to finished the preliminary design. In the meanwhile, the design philosophies of the aluminum alloy piston and composite piston for the 190 series diesel engines were used for reference in the design process. The designed steel piston was tested in the engine durability bench test and simulated for reliability. The results showed that the failure of the steel piston occurred at the same position in both the test and the simulation. The cause of cracking in the steel piston was analyzed, and the insufficient strength of the local structure led to high-cycle fatigue failure. Based on the failure mechanism, the modified design was carried out. The improved steel piston not only satisfied the fatigue strength assessment but passed the engine durability bench test successfully. Finally, the design development of the steel piston was finished. This study has significance for the design of steel pistons for large-bore diesel engines.