Search Results

Due to the current federal requirements for increasing vehicle fuel economy, more engineering resources are allocated to the up-front analysis with the purpose of increasing vehicle fuel economy. Engine friction is one of the biggest factors influencing the fuel economy. The cylinder bore distortion plays an important role for the friction between the sliding pistons and the cylinder bore. The quality of the cylinder bore distortion has significant impact on the overall engine efficiency and performance. The cylinder bore distortion will result into consequences such as power loss, blow-by, oil consumption, and NVH issues. To meet the cylinder bore distortion requirements, the engineering community turns efforts to the early design stage during product development. The CAE applications in the design of automotive engine have become an essential tool. Both the cost and cycle of the product development benefit from its usages.

Cyclic firing loading conditions coupled with high thermal loads are the main causes for failure of the cylinder head. A complete thermo-mechanical fatigue analysis of a cast aluminum cylinder head should include both high and low cycle fatigue. Reliable nonlinear material behavior, accurate thermo-mechanical stress analysis, and dependable failure criterion are the keys to successful life prediction. The low cycle fatigue is primarily due to thermal stress resulted from repeated start-up and shut-down cycle of the engines. The high cycle fatigue is mainly due to the firing loads, as amplitude stress, accumulated to the mean stress due to the thermal load. In this paper the required CAE simulations for high/low cycle fatigue of cylinder head will be discussed.