Investigations on ablation failure of high power pistons

Numerical simulation of combustion characteristics at wall burning condition in a diesel engine was conducted using software AVL FIRE, and the thermal boundary conditions of finite element calculation for piston at wall burning condition were obtained. Moreover, the finite element analysis of piston during ablation process was carried out using software ANSYS, and the rules of influence of wall burning on piston ablation were achieved. Meanwhile, a corresponding experiment of piston ablation was made on the diesel engine, and the calculated results accorded with the experimental results. The results show that the resolving method established can be used to simulate the ablation process of piston. The abrasion of injection nozzle, which leads to bigger gas temperature and wall heat transfer coefficient of gas on piston throat in a wide crank angle range, may cause ablation failure of piston. Meanwhile, the ablation amount firstly increases and then decreases with the increase of diameter of injection nozzle, and peaks when the diameter increases by 15%. The ablation amount increases with the ablation time, but the speed of ablation reduces slowly.