Integration of Sensitivity Analysis and Design for Six Sigma (DFSS) Methodology into Transient Thermal Analysis

In this paper we present an integrated approach which combines analysis of the effect of simultaneous variations in model input parameters on component or system temperatures. The sensitivity analysis can be conducted by varying model input parameters using specific values that may be of interest to the user. The alternative approach is to use a structured set of parameters generated in the form of a DFSS DOE matrix. The matrix represents a combination of simulation conditions which combine the control factors (CF) and noise factors. CF’s are the design parameters that the engineer can modify to achieve a robust design. Noise factors include parameters that are outside the control of the design engineer. In automotive thermal management, noise factors include changes in ambient temperature, exhaust gas temperatures or aging of exhaust system or heat shields for example. The integrated approach, presented in this paper, provides powerful tools that can significantly reduce the total simulation time and helps to provide robust thermal protection scenarios. The relative importance of the CF’s can be estimated, and the least costly but effective design can therefore be considered. An example is illustrated for optimization of catalytic converter design in order to reduce its impact on surrounding component temperatures.