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Development of the Matrix Infrared Sensor and Climate Control System Using this Sensor Takuya KATAOKA Tatsumi KUMADA Drivers and passengers always tend to require more comfortable climate control in

1 Development of the Matrix Infrared Sensor and Climate Control System Using this Sensor Takuya KATAOKA Tatsumi KUMADA Drivers and passengers always tend to require more comfortable climate control in vehicles. This paper is concerned with the development of a newly developed infrared sensor measuring surface temperatures at six separate locations, and an advanced climate control system that incorporates this sensor. In a conventional systems using an air temperature sensor and solar radiation sensor, climate conditions are usually controlled according to the thermal load. It is believed that more comfortable climate control will be realized by using the infrared sensor to monitor passenger s surface temperature. The sensor consists of a lens, an IC with six thermopiles, a circuit and a case, and was developed to measure cabin-interior surface temperature accurately even under severe outside environmental conditions. The HVAC system controls the outlet air temperature and the mode individually for each seat according to the measured temperatures. Even though, a passenger may get in a vehicle from a very hot or cold environment, the system estimates the passengers thermal conditions from the measured temperature and controls the HVAC to adjust the climate condition of each passenger appropriately and quickly. This proposed control system realizes a pleasant thermal feeling of climate control for the passenger. Key words: Climate control, Air conditioning, Thermal comfort, Sensing, Infrared sensor Table 1 Sensing methods and applications of infrared sensors Methodology Thermopile Applications Thermometer Thermal type Pyroelectric element Sensitivity switch Quantum type Bolometer Photodiode Photoransistor Photoconductive tube Radiation meter Thermograph Color sensor Illuminometer Photocell Thermopile Filter Infrared radiation Pins Can Stem Thermistor Hot junction Cold junction Fig. 1 Structure and principle of thermopile infrared sensors

2 Radiation energy Visible Light Object Expected bene t Required accuracy Required resonance Mid Infrared Near Infrared Interior Thermal load in passenger compartment Sensing area of the Infrared thermometer Passenger s clothing C C C Wave length (μm) Table 2 Application of infrared sensors for vehicle climate control Passenger s skin Thermal state Thermal state and conditions of and sensations of passenger passenger ±1. to 2. K ±1. to 2. K ±.3 to.7 K Far Infrared Fig. 2 Radiant energy distribution and measuring area of infrared thermometers Glass Fogging (w/ humidity sensor) Depends on purpose.7 to 1 m.1 to.3 m.2 to.3 m.1 to.3 m

3 Mean skin temperature ( C) TO: - to Va:.1 to 1. m/s RH: to 8% RH Clo:.6 Mean skin temperature ( C) TO: - to Va:.1 to 1. m/s RH: to 8% RH Clo: function Clothing surface temperature ( C) - - SET* Fig. 3 Relation between SET* and mean skin temperature (Clo =.6) TO: - to Va:.1 to 1. m/s RH: to 8% RH Clo: SET* Fig. 4 Relation between SET* and clothing surface temperature (Clo =.6) Clothing surface temperature ( C) - - SET* Fig. Relation between SET* and mean skin temperature (Clo: function of ambient air temperature, with a deviation of ±.2) TO: - to Va:.1 to 1. m/s RH: to 8% RH Clo: function - - SET* Fig. 6 Relation between SET* and clothing surface temperature (Clo: function of ambient air temperature, with a deviation of ±.2)

Set temperature TSET HVAC Electronic Control Unit TA TS TR Ambient air

7 Single Infrared sensor Infrared sensor Fig.

8 Sensor equipped on an Instrument panel Image of sensing area Room air

9 Measuring area of the sensor (right hand drive vehicle) Temperature (

4 Set temperature TSET HVAC Electronic Control Unit TA TS TR Ambient air temp. sensor Solar radiation sensor Room air temp. sensor Fig. 7 Single Infrared sensor Infrared sensor Fig. Conventional climate control system Fig. 8 Sensor equipped on an Instrument panel Image of sensing area Room air temperature C (A photo of a vehicle with right hand drive) Fig. 9 Measuring area of the sensor (right hand drive vehicle) Temperature ( C) Door trim Ceiling Side window Ambient air temperature ( C) Fig. 11 Interior surface temperature sensitivity with changes in ambient air temperature

5 Temperature ( C) Side window Ambient air temperature C Room air temperature C Door trim Ceiling Solar radiation (W/m 2 ) Fig. 12 Interior surface temperature sensitivity with changes in solar radiation Fig. Matrix infrared sensor Room air temperature ( C) Conventional IR Cover Sensor - Ambient air temperature ( C) Fig. 13 Results of ambient air temperature correction Ambient air temperature C Fig. 16 Cross sectional view around the sensing element Room air temperature ( C) Conventional IR Solar radiation (W/m 2 ) Fig. 14 Results of solar radiation correction 6 Fig. 17 Sensing area of the matrix infrared sensor

Matrix IR sensor Areas where surface temperature is detected 6 mean sensed

6 Matrix IR sensor Areas where surface temperature is detected 6 mean sensed temperature Object temperature Temperature ( C) Maximum deviation in the six cells Fig. 18 Installation position and measuring areas of the Matrix IR sensor Time (min) Fig. Comparison of the sensor transient condition Matrix IR sensor LIN Electronic Control Unit Fig. 19 Sensor installed in a vehicle 4zone control Front HVAC Rear FACE B Pillar Rear FOOT Rear air conditioner Rear SIDE Ceiling Fig. 21 Overview of the system Summer: Hot passenger gets in Winter: Cold passenger gets in Fig. 22 Illustrations of thermal history control

7 Temperature change ( C) Chest Waist Legs Time (Min) Fig. 23 Temperature change over time with thermal history control activated Thermal sensation Thermal sensation Very hot With IR sensor Hot Without IR sensor Warm Slightly warm Neutral Slightly cool Time (min) Summer condition: Ambient air temperature C Slightly warm Neutral Slightly cool Cool With IR sensor Cold Without IR sensor Very cold Time (min) Winter condition: Ambient air temperature C Fig. 24 Effects of thermal history control

Vol. 51 No (2000) Thermo-Physiological Responses of the Foot under C Thermal Conditions Fusako IWASAKI, Yuri NANAMEKI,* Tomoko KOSHIB

Vol. 51 No (2000) Thermo-Physiological Responses of the Foot under C Thermal Conditions Fusako IWASAKI, Yuri NANAMEKI,* Tomoko KOSHIB Vol. 51 No. 7 587-593 (2000) Thermo-Physiological Responses of the Foot under 22-34 C Thermal Conditions Fusako IWASAKI, Yuri NANAMEKI,* Tomoko KOSHIBA and Teruko TAMURA * Junior College Division, Bunka