A FEM Thermal Analysis on a Novel Designed Air-Gap Insulated Piston 932490

A novel design of an air-gap insulated piston has been proposed which is expected to give a longer life compared to the past designs and lower heat transfer there by increasing its crown temperature. Also it is light weight. The basic design of the piston, where the crown is separated from the body of the piston through a thick composite gasket. The crown and the piston base are fitted together by an interference fitting and locked by oval shaped rivets. A steady state two dimensional thermal analysis is done on the piston for the following five cases using FEM: Aluminum piston single piece as reference, aluminum crown with thick composite gasket and air-gap with aluminum base, composite crown and air-gap with aluminum base, all composite piston without air-gap and all composite with air-gap. Constant temperatures are assumed at gas, liner and oil boundaries of the piston. Also the film coefficients on the piston boundaries are kept constant for all the cases. The analysis gives a detailed study on the temperature distribution in the piston and heat flux through different surfaces of the piston. Heat loss reduction ranged between 17.4% to 60% in the four cases compared with the reference piston. Similarly, the crown temperature increased in the range of 16.3% to 76.4%.