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Simple thermodynamic and heat transfer mathematical models have been developed to aid in the study of HVAC system designs in field testing. The refrigeration system, heating system and vehicle cabin have been examined. Test data are used to determine parameter values in governing equations. These parameter values may be used for performance simulation and competitor comparison. A benefit of this approach is that individual component performance can be extracted from system performance. Another benefit is that performance data can be adjusted, for comparison purposes, to identical test conditions.

Many reports about disc-brake squeal have been presented based on experimental or theoretical research in the past. However, there have been few in which theoretical analysis corresponding with experimental results has been used to explain the cause mechanism and nature of disc-brake squeal. By performing extensive experimental measurements and calculation using simulation models at the same time, a mechanism of disc-brake squeal has been developed to explain our results fully. It is clear from the results of our analysis that brake squeal is self-induced vibration between each brake part-pad, cylinder, disc etc.--and its growth can be classified into two patterns. The first is characteristic of the worst (or optimum) values and depends upon parameters such as mass, stiffness, etc.--, and the second increases with increases in other parameters--the coefficient of friction, moment arm, etc.