Use of Infra-Red Thermography for Automotive Climate Control Analysis

Abstract

greatest possiblethermal resolution, in most systems, the sensorconsistsof a singleinfra-reddetector(suchas In this paper, several automotive climate control mercury/oadmlum/telluride). Electromechanicalservos applications for IR thermographyare described. Some of (galvanometers)oscillate mirrors to perform horizontal these applicationscan be performed usingconventional and verticalscanningof the image ontothe detector.The IR techniques. Others, such as visualizing the air detector respondsto the sum of the emitted, reflected, temperature distributionwithin the cabin, at duct exits, and transmitted energies (radiosity) coming from the and at heater and evaporator faces, require new target. experimental methods.In order to capture the 1"oobtainthe targettemperature,the emittedenergy temperaturedistribution withinan airstream, a O.25-mm-must be separatedfrom the total radiosity. The emitted thick (0.01 inch) fiberglass screen is used. This screen energy must be compensated(scaled up) by the target can be positionedperpendicularor parallelto the flow to emittanceto obtain an equivalentblackbodyemittance. obtainthree-dimensional spatialmeasurements. In many Finally, this blackbody emittance is converted to a cases, the air flow pattern can be inferred from the temperatureby referenceto Planckblackbodydistribution resultingtemperature distribution, allowingimprovedair information. In this way, an IR imaging system can distribution designs. In all cases,significantimprovement captureand process108temperature measurementsper in the speed, ease, and quantity of temperature second. These signalsare digitizedby a microprocessor distribution informationcan be realizedwiththermography and converted to grey-scale or color video images. A as compared to conventional thermocouple array high-resolutionvideo recorder can be used to store techniques. Comparisons are presented between IR transient images for later post-processing. Typical thermography images and both thermocouple personal computer or workstation post-processing measurementsand computational fluid dynamics(CFD) capabilitiesinclude identificationof isotherms,minimum predictions, and maximumtemperatures,and temperatures along a particularline,curve, or boundary. As a real-time interactive diagnostic tool, IR

Thermal comfort models for indoor spaces and vehicles—Current capabilities and future perspectives

“…The Infrared thermography is non-invasive, non contact imaging approach that has been proposed by certain authors to measure the temperature variation on the human skin temperature [25,122,123]. As shown by Alahmer et al [3], using infrared thermography is possible to achieve real-time measurements of solid surfaces temperature fields within the vehicular cabin in addition to clothes and visible body parts of the human subjects.…”

“…There is a limited number of papers in the literature discussing the use of infrared thermography to measure and evaluate the thermal conditions inside the cabin, even though this optical technique seems to be a promising tool in the assessment of the comfort state in vehicular cabins, given that the surface's temperature is one of the most influencing parameters in this case. An early study of Burch et al [122] displays several automotive applications of infrared thermography with focus on its use for automotive climatic control analysis. The author proposes a method for measuring ambient air temperature by using a thin (0.15 mm) layer of polyethylene plastic mounted perpendicular to the air stream.…”

Gas temperature imaging using the heated grid technique with adaptive background correction

“…By inserting a high emissivity mesh into the flow (e.g. Anderson et al [2], Burch et al [3]), IRT can be used to measure temperature distributions in flow fields. In the past, different materials, such as paper screens, have been used (e.g.…”

Passenger Thermal Comfort in Vehicles - A Review

“…It was found that period in this case. This method had previously ventilation would bring the seat temperature to that been proposed by Burch et al [35] in 1993 for of the ambient and increase the thermal comfort of other automotive applications. The results were the passenger.…”