Thermal Load Analysis of Piston Damaged by Wall-Wetting Combustion in a Heavy-Duty Diesel Engine

Abstract

Piston damage is a frequent problem of engine durability and plays an important role in an engine’s performance design. Recently, a large amount of piston erosion has occurred in a series of heavy-duty diesel engines. To investigate the reason for the piston erosion, a study of the computational fluid dynamics (CFD) of the combustion process in the cylinder and finite element analysis (FEA) of piston was carried out under different initial temperatures. The results show that when the initial temperature decreases from 380 K to 307 K, the mass of wall-wetting increases by 73%, and the maximum combustion pressure increases from 8.1 MPa to 11 MPa; when the initial temperature decreases from 350 K to 328 K, the highest temperature at the throat of the valve pocket increases by nearly 100 K, doubling the temperature fluctuation; and in the case of 328 K, areas exceeding 700 K are concentrated on the top surface of the piston, and the temperature gradient in the depth direction of the throat position decays rapidly.