Piston Bowl Rim Cracks-A More Detailed Analysis

Today's trends to higly rated engines as well as reentrant bowls with sharp corners to meet emission requirements have made the combustion bowl rims of DI Diesel engine pistons proner to crack.

The usual method of analysing this problem through Goodman's Diagram, does not consider: (i) peak stresses due to thermal transients; (ii) the sequence of events which alters mean stresses in each applied cycle and (iii) the material properties under cyclic loading.

In order to overcome these points, a more detailed analysis using the strain life method has been performed. Results were then compared to engine tests.