MEASURING CUSTOMER PERCEIVED THERMAL COMFORT IN CAR CABIN COMPARTMENT: INDEX OF PERCEIVED THERMAL COMFORT

摘要

During the early phases of a new model car development it is of outmost importance to know and predict the customer perception. The first step is the identification and deployment of the perception structure, after that it is necessary to the correlate the subjective perception with physical measurements. The paper describes how this approach has been applied to the Thermal Comfort. Thermal comfort perception in car cabin compartments depends on many factors. Well being sensation is not only a function of air temperature but of all the other quantities that influence thermal exchange between the body and the surrounding environment. The CRF developed the EVA3 thermal manikin to assess the cabin Thermal Comfort . Centro Ricerche FIAT, after several experimental campaigns, identified an algorithm able to correlate panel tests judgments with a the physical measured made with the EVA3 thermal manikin and other physical quantities. Road tests have been performed, during winter and summer, with over 30 cars and 100 people. All cars have been instrumented both conventional sensors and with EVA3 thermal manikin (developed by Centro Ricerche Fiat and ISO 9001 certified) that measures the equivalent temperature in 18 points of the body surface. In parallel, people were asked to answer a detailed questionnaire conceived by cognitive ergonomists, whose aim is to establish people perception of thermal comfort. An analysis has been performed to discriminate which quantities, among those that have been measured, could be better correlated to people judgement. Then an index has been developed by means of statistic regressive techniques. An 89% correlation has been obtained between subjective collected data and customers predicted vote by the index. Validation experiments have also been carried out showing the Index reliability and robustness.