WO2005026712A1 - ガス検出装置 - Google Patents
ガス検出装置 Download PDFInfo
- Publication number
- WO2005026712A1 WO2005026712A1 PCT/JP2003/011526 JP0311526W WO2005026712A1 WO 2005026712 A1 WO2005026712 A1 WO 2005026712A1 JP 0311526 W JP0311526 W JP 0311526W WO 2005026712 A1 WO2005026712 A1 WO 2005026712A1
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- WIPO (PCT)
- Prior art keywords
- gas
- sensor
- reference value
- update
- value
- Prior art date
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- 238000001514 detection method Methods 0.000 claims abstract description 86
- 238000011109 contamination Methods 0.000 claims abstract description 66
- 238000005070 sampling Methods 0.000 claims abstract description 18
- 239000004065 semiconductor Substances 0.000 claims description 22
- 230000035945 sensitivity Effects 0.000 claims description 12
- 230000007423 decrease Effects 0.000 claims description 11
- 238000012937 correction Methods 0.000 claims description 9
- 238000010410 dusting Methods 0.000 claims description 5
- 238000005259 measurement Methods 0.000 claims 1
- 239000007789 gas Substances 0.000 description 324
- 238000000034 method Methods 0.000 description 14
- 238000004140 cleaning Methods 0.000 description 10
- 238000012545 processing Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 239000000428 dust Substances 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 230000003111 delayed effect Effects 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 210000001215 vagina Anatomy 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000004378 air conditioning Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 229910000510 noble metal Inorganic materials 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- 229910001887 tin oxide Inorganic materials 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- -1 Hydride carbon Chemical compound 0.000 description 1
- 235000014676 Phragmites communis Nutrition 0.000 description 1
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- SAZUGELZHZOXHB-UHFFFAOYSA-N acecarbromal Chemical compound CCC(Br)(CC)C(=O)NC(=O)NC(C)=O SAZUGELZHZOXHB-UHFFFAOYSA-N 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 230000008786 sensory perception of smell Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0062—General constructional details of gas analysers, e.g. portable test equipment concerning the measuring method or the display, e.g. intermittent measurement or digital display
- G01N33/0063—General constructional details of gas analysers, e.g. portable test equipment concerning the measuring method or the display, e.g. intermittent measurement or digital display using a threshold to release an alarm or displaying means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- B60H1/00—Heating, cooling or ventilating [HVAC] devices
- B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
- B60H1/0073—Control systems or circuits characterised by particular algorithms or computational models, e.g. fuzzy logic or dynamic models
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- B60H1/00—Heating, cooling or ventilating [HVAC] devices
- B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
- B60H1/00735—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models
- B60H1/008—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models the input being air quality
Definitions
- the present invention relates to a gas detection device for detecting exhaust gas and malodorous gas in the atmosphere.
- gas detection devices that detect exhaust gas in the atmosphere have been provided in order to automatically control the switching of a damper that switches between inside air circulation and outside air introduction in an air conditioning system of an automobile.
- the damper When the detected exhaust gas concentration exceeds a certain level, the damper is switched to inside air circulation to prevent dirty outside air from entering the vehicle interior.
- the damper When the exhaust gas concentration falls below a certain level, the damper is switched to introduction of outside air. And clean outside air was introduced into the passenger compartment.
- a gas sensor used in such a gas detection device is required to be inexpensive and highly durable, so a semiconductor gas sensor using a metal oxide semiconductor is suitable.
- a semiconductor gas sensor has a temperature and humidity atmosphere.
- the output of the semiconductor gas sensor is sampled every unit time to obtain a change ⁇ . It was judged that exhaust gas was present where the predetermined threshold was exceeded.
- this reference value is compared with the current output, and if the difference between the two is large, it is determined that there is exhaust gas.
- Devices have also been provided in the past (see, for example, Japanese Patent Application Laid-Open No. 200-28 1 1 85). However, only a high concentration could be detected, and despite the presence of exhaust gas, the damper was left switched to the outside air side, causing dirty outside air to flow into the vehicle.
- this reference bell is compared with the current output using the lowest gas concentration in a certain period in the past as a reference value, and if the difference between the two is large, the exhaust gas There is also a device that has been judged to be present, but if the lowest gas concentration, which has temporarily dropped sharply due to noise or other factors, is used as a reference point, clean air is mistakenly detected as dirty air, and the damper There was a problem that was still switched to the shy side. Disclosure of the invention
- the present invention has been made in view of the above problems, and its purpose is that the gas concentration of exhaust gas and malodorous gas when a person feels that the air is dirty due to the difference in location and the like is different. Even in this case, a gas test can be performed to ensure the presence of exhaust gas and odorous gas. To provide a dispensing device.
- the resistance fluctuates according to the exhaust gas discharged from automobiles and the gas concentration of malodorous gas generated from factories, sewage treatment plants, waste treatment plants, ranches, farms, etc.
- the first contamination signal indicating the degree of air contamination obtained from the deviation between the semiconductor gas sensor and the output of the semiconductor gas sensor at a predetermined sampling period and the sensor resistance ⁇ calculated from this output and the predetermined first reference ⁇ .
- the reference value update unit has a high gas concentration. Dirt direction compared to the case of updating the first reference ⁇ , and accelerate the update rate in the case of updating the first reference ⁇ cleaned direction in which the gas concentration decreases.
- the update amount is obtained by multiplying the deviation between the current sensor output and the first reference value at the previous update by the update ratio, and this update amount is obtained at the time of the previous update. Since this first reference value is obtained by adding it to the first reference fence, the first reference value can be changed according to the surrounding environment.
- the gas concentration is different, the first contamination signal can be used to reliably contact the presence or absence of exhaust gas or odorous gas. Therefore, when controlling the damper of an automobile using the output of this gas detection device, it is possible to perform damper control that suits the human sense in any environment.
- the first standard Since the renewal speed when updating in the clean direction is faster than the renewal speed when updating the reference value in the dirt direction, if the gas concentration continues to be high for a long time, the first standard Since the value gradually changes in the direction of dirt, it is possible to prevent the first reference value from going too far in the dirt direction and switch the damper to the outside, and there are always exhaust gases and odorous gases as in urban areas. If you stay at the place for a long time, the human sense of smell is used to the environment. In the same way as the first reference value approaches the value that matches the lowest gas concentration in the environment, it is possible to prevent the damper from being switched to the inside air side. In addition, when the air becomes clean, the first standard soot changes rapidly in the clean direction, and a small amount of exhaust gas or bad odor gas is detected and the damper is switched to the inside air side. Tampering can be controlled.
- the reference reed update unit further shortens the first update period when updating the first reference value in the clean direction compared to the first update period when updating the first reference value in the dirty direction.
- the update speed in the cleaning direction can be increased by shortening the first update period when updating in the clean direction compared to the first update period when updating the first reference value in the dirt direction.
- the reference bell update unit further increases the value of the update ratio used when updating the first reference value in the clean direction as compared with the update ratio used when updating the first reference value in the dirt direction. It is preferable.
- the renewal rate in the clean direction can be increased by increasing the value of the renewal rate used for lifting that is updated in the clean direction compared to the renewal rate used when the first reference value is updated in the dirty direction.
- the update ratio is a value inversely proportional to the magnitude of the first contamination signal.
- the value obtained by subtracting the reference value from the sensor output and the update ratio is the update amount of the first reference value.Therefore, in a high gas concentration atmosphere, the update amount becomes large and the first reference value becomes Although it tends to change to the high concentration side in a relatively short time, the update rate of the first reference value can be increased in an atmosphere with a high gas concentration by setting the update ratio to a value inversely proportional to the magnitude of the first contamination signal. Can be delayed.
- the gas determination unit further corrects the variation in sensitivity among the sensors to a value obtained by dividing the difference between the output of the semiconductor gas sensor and the first reference value by the first reference value.
- the correction coefficient to be multiplied is preferably used as the first contamination signal.
- the sensor output is temperature dependent, but the sensor resistance that changes with temperature and humidity is obtained by dividing the deviation between the sensor output and the first reference value by the first reference value to obtain the resistance ratio. Sensitivity can be normalized so that it does not depend on the value, and a correction factor is applied. Variation in sensitivity among individual sensors can be eliminated.
- the gas detection device as the semiconductor gas sensor, a first sensor whose resistance bell increases as the exhaust gas concentration of the diesel vehicle increases, and a resistance value as the gas concentration of the exhaust gas and malodorous gas of the gasoline vehicle increases.
- the gas determination unit is provided for each of the first and second sensors, and the reference value update unit determines the first reference value of each gas determination unit. It is preferable to update each independently.
- each gas determination unit obtains the first contamination signal from the deviation between the output of the first sensor or the second sensor and the respective first reference rod.
- the presence or absence of exhaust gas and offensive odor gas can be detected using the first dirt signal, and when controlling the damper of an automobile using the output of this gas detection device, the exhaust gas of both diesel and gasoline vehicles is used. And it is possible to switch the damper to the inside air side by knowing bad odor gas.
- the reference value updating unit sets the first reference value on the second sensor side in the clean direction when the first contamination signal obtained from the output of the first sensor becomes equal to or higher than a predetermined first threshold level.
- the reference value update prohibition on the second sensor side is canceled, and the first contamination signal is obtained from the output of the second sensor.
- the value exceeds the predetermined second threshold level it is prohibited to update the first reference bell on the first sensor side in the clean direction, and below the second threshold level, the reference on the first sensor side is prohibited. It is preferable to cancel the prohibition of value update.
- the first sensor is slightly sensitive to exhaust gas and odorous gas from gasoline cars
- the second sensor is also slightly sensitive to exhaust gas from diesel cars.
- the output of the engine changes in the clean direction when exhaust gas and odorous gas from gasoline cars are present
- the output of the second sensor changes in the clean direction when exhaust gas from diesel cars exists.
- the output of each sensor is fetched at the sampling period for each of the first and second sensors, and the second obtained from the deviation between the output and a predetermined second reference value.
- a low-concentration gas determination unit that outputs a contamination signal is provided, and each time the second update period that is longer than the sampling period and shorter than the first update period passes by the reference value update unit, the current output of each sensor.
- the value obtained by multiplying the difference between the vagina and the second reference vagina at the previous update by a predetermined coefficient smaller than 1 and adding the second reference value at the previous update is the new second reference value for each sensor. It is preferable to shorten the second update cycle when updating the second reference value in the clean direction, compared with the second update cycle when updating the second reference value in the dirty direction.
- the first fouling signal threshold (detection level) is set to a small value, and the first reference value is too small in the clean direction.
- the detection level is set to a large value, low-concentration exhaust gases and odorous gases will be generated. If it becomes difficult to detect or controls the damper, the response of the damper will be slow, but this second reference value will be compared with the second reference value, which is faster than the update speed of the first reference value.
- the second contamination signal threshold (low concentration detection level) is set to a concentration lower than the detection level of the first contamination signal.
- the gas judgment unit can detect exhaust gases and odorous gases with relatively high concentrations, and when the detection level of the first contamination signal is set high, the renewal speed is compared. Therefore, exhaust gas and odorous gas can be detected reliably with reduced false detections.
- the damper is opened and closed based on the first and second contamination signals with respect to the opening and closing device that opens and closes the damper for introducing outside air into the vehicle interior of the automobile.
- a switching control unit that outputs a switching signal, wherein the switching control unit is configured such that the first dirt signal exceeds a predetermined dust level or the second dirt signal exceeds a predetermined low concentration detection level.
- a switching signal for closing the damper is output, and when both the first and second contamination signals are below the contact level and the low concentration detection level, the predetermined time is limited. Start the timer, and if the 1st and 2nd contamination signals do not exceed the contact level and the low concentration detection level respectively while the timer is counting, output the switch when the timer counts up. Is preferred.
- the damper is closed for a predetermined time, and exhaust gas and odorous gas are extracted during that time. Otherwise, since the damper is opened after a predetermined time, the probability that the tamper is closed immediately after the damper is opened is reduced, and the life of the motor that drives the tamper can be extended by reducing the number of times the damper is opened and closed.
- the second contamination signal from each low-concentration gas determination unit is detected until the predetermined stop time elapses after the switching control unit outputs a switching signal for turning on the damper. It is preferable to stop the output of the switching signal that closes the damper after the level is exceeded.
- the second dirt signal from the low-concentration gas determination unit exceeds the low-concentration detection level and is ignored until the stop time elapses after switching the damper to the outside air side.
- the control is not performed in the middle of being closed, and it is possible to extend the life by reducing the unnecessary load on the motor that drives the damper.
- the switching control unit stops outputting the switching signal for closing the tamper based on the second contamination signal input from the low concentration gas determination unit on the first sensor side.
- the output of the first sensor changes to the clean side when there is exhaust gas and bad odor gas from a gasoline car, it is clean after being exposed to high concentration exhaust gas and high concentration odor gas from a gasoline car.
- the output of the first sensor changes in the direction of contamination, and this change in output may be judged by the low-concentration gas determination unit as air contamination, but the gas determination unit on the second sensor side
- the determination by the low-concentration gas determination unit on the first sensor side is stopped, and then input from the low-concentration gas determination unit on the first sensor side. It is possible to prevent the damper from being closed by preventing erroneous determination that clean air is dirty based on the second contamination signal.
- FIG. 1 is a block diagram of a damper control system using a gas detector according to an embodiment of the present invention.
- ⁇ 2 is an explanatory diagram for updating the reference value.
- FIG. 3 is a front view of the first sensor used in the above with a part omitted.
- ⁇ 4 is a flowchart of the air quality determination operation using the first sensor.
- Fig. 5 is a flowchart of the air quality determination operation using the second sensor.
- ⁇ 6 is a routine routine for updating the first reference value of the first sensor in the same direction as above.
- Completion is the first step in the routine to update the first reference value of the second sensor in the same direction as above.
- ⁇ 8 is a routine routine for updating the first reference value of the first sensor in the same direction as above.
- Fig. 9 is a flowchart of the routine for updating the first reference value of the second sensor in the above direction in the dirt direction.
- FIG. 10 is a block diagram of a damper control system using the gas detection device of another embodiment.
- Fig. 11 is a flowchart showing the damper control operation.
- FIG. 1 shows a block diagram of the gas detector A of the present embodiment.
- This gas detection device A has a first sensor 1 sensitive to diesel exhaust emitted from a diesel vehicle and a second sensor sensitive to gasoline exhaust and malodorous gas emitted from a gasoline vehicle.
- Sensor 2 AZD converters 3 a and 3 b, first gas determination unit 4 a that determines the presence or absence of diesel exhaust gas based on the output of the first sensor 1, and the output of the second sensor 2
- the main components are the second gas determination unit 4b, the switching control unit 5, the reference lamp update unit 6, and the sensor drive unit 7, which determine the presence or absence of galiline exhaust gas and malodorous gas.
- 0 converters 3 &, 3 b, first and second gas determination units 4 a, 4 b, switching control unit 5, reference vagina update unit 6, and sensor driving unit 7 have built-in AZD converters. It is configured using a microcomputer.
- This gas detection device A is used in an automobile damper control system. At one end of a duct 11 that guides air into the vehicle interior, an outside air introduction duct 1 2 that introduces air outside the vehicle, The inside air introduction duct 13 that guides air through circulation is connected.
- a damper 20 for switching the air inflow path to duct 1 2 or duct ⁇ 1 3 is arranged at the connecting part between ducts 1 2 and 1 3 and duct 1 1, and damper drive unit 2 1 is a switching control unit. Based on the switching signal input from 5, the damper 20 is switched to the outside or inside air side.
- a fan (not shown) of the blower is disposed downstream of the duct 1 1. When the fan is operated, the air taken in from the duct 1 2 or 1 3 passes through the duct 1 1. It is led to the passenger compartment.
- the gas detector A uses the first and second sensors 1 and 2 to detect the exhaust gas concentration and malodorous gas concentration emitted from diesel vehicles and gasoline vehicles, and the exhaust gas concentration and malodorous gas concentration.
- Dumbar 20 is increased when 1 becomes higher.
- the damper 20 is switched to the duct 1 2 side to take clean outside air into the passenger compartment.
- the first sensor 1 used in the gas detection device A is a conventional sensor that changes in the direction in which the resistance value of the gas sensing body increases as the gas concentration of NOx and other oxidizing gases emitted from diesel vehicles increases. As shown in FIG. 3, it has a gas sensitive body 1a formed of a metal oxide semiconductor such as tin oxide (SnO 2 ) as a main component and formed into a substantially spherical shape. 1 A heater combined electrode 1 b made of platinum in a coil is embedded in a, and a resistance detection electrode 1 c made of a noble metal wire is passed through the center of the coil of the heater combined electrode 1 b. 1 Embedded in a.
- a metal oxide semiconductor such as tin oxide (SnO 2 )
- lead wires 8a and 8c are formed from both ends of the heater combined electrode 1b protruding from the gas sensing element 1a, and one end of the resistance detection electrode 1c protruding from the gas sensing element 1a. Leads 8b.
- the first sensor 1 is attached to three terminals 9a to 9c penetrating the resin base 10 via lead wires 8a to 8c.
- FIG. 1 shows the configuration of a circuit that controls the heating of the heater combined electrode 1 b of the first sensor 1 and detects the gas to be detected from the resistance value change of the gas sensing element 1 a.
- the constant voltage V c is applied to the heater combined electrode 1 b of the first sensor 1 via the switch element Q 1, and the heater combined electrode 1 b is energized when the switch element Q 1 is turned on.
- the heater combined electrode 1b generates heat.
- a constant voltage V c is applied to the resistance detection electrode 1 c through a series circuit of the load resistance R 1 a and the switch element Q 2 and the load resistance R 1 b, and the resistance detection electrode 1 c is connected to the input terminal of AZD converter 3a.
- Switch elements Q 1 and Q 2 are switched on and off by the output signals a and b from the sensor drive unit 7, and when the switch element Q 1 is turned on for a predetermined time by the output signal a of the sensor drive unit 1
- the gas sensitive body 1a is heated by the heat generated by the heater electrode 1b. Therefore, the sensor drive unit 7 is operated at a predetermined time (about ⁇ .
- the gas sensing element 1a is heated to about 300 ° C by duty control to energize the heater combined electrode 1b for only 16 mS).
- the AZD converter 3 a converts the voltage across the first sensor 1 to AZD every predetermined sampling period ts and converts it to a digital value.
- V d is output to the first gas determination unit 4 a.
- the switch element Q 2 is turned on by the output signal b of the sensor drive unit end, the load resistance R 1 b is connected in parallel with the load resistance R 1 a, and the load connected to the resistance detection electrode 1 c
- the combined resistance value of the resistors can be switched between two ways. That is, the sensor drive unit 7 switches on / off of the switch element Q 2 in accordance with the signal level input to the A / D converter 3 a. When the signal level decreases, the switch element Q 2 By turning on and reducing the load resistance bell, the signal level input to the AZD converter 3a is increased to prevent a decrease in detection accuracy.
- the second sensor 2 reduces the resistance of the gas sensor when the gas concentration of reducing gas such as HC and C ⁇ bad odor gas (for example, ammonia) contained in the exhaust gas from a gasoline vehicle increases.
- reducing gas such as HC and C ⁇ bad odor gas (for example, ammonia) contained in the exhaust gas from a gasoline vehicle increases.
- composed consists conventionally known semiconductor gas sensor that varies in direction, has the same structure as the first sensor 1, a substantially tin oxide (S N_ ⁇ 2) of which a metal oxide semiconductor as a main component A gas sensitive body formed in a spherical shape is provided, and the heater combined electrode 2b made of coiled platinum is embedded in the gas sensitive body and penetrates the center of the coil of the heater combined electrode 2b.
- the resistance detection electrode 2c made of noble metal wire is embedded in the gas sensitive body.
- a constant voltage V c is applied to the heater combined electrode 2 b of the second sensor 2 via the switch element Q 3, and the load resistance R 2 a and the switch element Q are applied to the resistance detection electrode 2 c.
- a constant voltage V c is applied through a series circuit of 4 and the load resistance R 2 b, and the resistance dusting electrode 2 c is connected to the input terminal of the AZD converter 3 b.
- Switch elements Q3 and Q4 are switched on and off by output signals c and d from sensor drive unit 7, and switch element Q3 is switched by output signal c from the sensor drive unit. When turned on for a certain period of time, the heater combined electrode 2b is energized.
- the sensor drive unit 7 performs duty control to energize the heater electrode 2b every predetermined period (for example, about 7.8 mS) for a predetermined time (about 0.19 mS). Heated to temperature. Then, during the period when the heater combined electrode 2 b is not energized, the AZD converter 3 b performs AZD conversion of the voltage across the second sensor 2 every predetermined sampling period ts, and the sensor output V converted to a digital value g is output to the second gas determination unit 4 b.
- the sensor drive unit 7 switches the load resistance value in two ways by turning on and off the switch element Q4 according to the signal level input to the A / D converter 3b, so that the detection accuracy decreases. Is preventing. In the sensor driving unit 7, the switch elements Q1 and Q3 are turned on half a cycle at a time so that the heater N period of the first sensor 1 and the heater ON period of the second sensor 2 do not overlap. The power consumption is reduced.
- Fig. 4 shows the operation in which the first gas determination unit 4a detects the exhaust gas from the diesel vehicle based on the output of the first sensor 1, and ⁇ 5 shows the second gas determination unit 4b in the second sensor 2.
- the operation of detecting the exhaust gas and malodorous gas of a gasoline car based on the output of the gas is shown respectively.
- the first and second gas judgment units 4a and 4b are set to a predetermined judgment value every predetermined sampling period. D1 D2, Judgment value ⁇ 31.
- steps S1, S1 1 1 After setting G2 (steps S1, S1 1), the resistance value Rd of both sensors 1 2 based on the sensor outputs V d, Vg input from AZD converters 3a, 3 b Rg is calculated (steps S2, S12).
- the full scale (256) is Vc, and resistance of detection resistor FM R2 If the value is 256, the resistance value Rd Rg of both sensors 1 2 is
- Rd VdX256 / (256-Vd)-(1)
- Rg VgX256 / (256— Vg)... (2)
- the reference heel update unit 6 performs the update process of the first reference values Rdm and Rgm used when obtaining the first dirt signals D and G, which will be described later.
- the reference value update unit 6 determines whether or not an update period t for updating the first reference rods Rdm and Rgm in the clean direction has elapsed (steps S3 and S13).
- Step S4 Each time the update period t of the first reference value Rdm on the first sensor side elapses in the determination of S3, the reference value update unit 6 executes a routine for updating the first reference value Rdm in the clean direction ( Step S4) and shift to the dirt determination routine (step S7). If it is not just the update cycle t, it is determined whether or not the update cycle T for updating the first reference value R dm in the dirt direction has passed (step S 5). Each time the update cycle T elapses in the determination of S5, the reference value updating unit 6 executes a routine for updating the first reference value Rdm in the dirt direction (step S6), and then proceeds to the dirt judgment routine. (Step S7), except when the update cycle T has elapsed, the process proceeds to the dirt determination routine (Step S7).
- the reference value update unit 6 determines that the resistance value Rg is greater than or equal to the reference value RgmO at the previous update. (Step S14), and if the resistance value Rg is greater than or equal to the reference value RgmO, after executing a routine to update the first reference value Rdm in the clean direction (Step S15), proceed to the contamination determination routine (Step S18).
- the update period T for updating the first reference value R gm in the dirt direction is It is determined whether or not it has elapsed (step S16). Then, every time the update cycle has passed in the determination of S16, the reference value updating unit 6 executes a routine for updating the first reference bell Rgm in the dirt direction (step S17), and then proceeds to the dirt judgment routine (step S17). Unless the update cycle T has elapsed (step S18), the process proceeds to the dirt determination routine (step S18).
- the reference value update unit 6 is prohibited to update the reference value in the clean direction. (S21), if not prohibited, compare the magnitude of the first contamination signal G obtained from the previous reference bell RgmO and the sensor resistance Rg and the predetermined judgment value G3 (S22) If the first contamination signal G or the 'judgment bell G3 or higher, updating the first reference value Rdm in the clean direction is prohibited (S25), and the update routine is terminated without updating the reference value.
- the reference bell update unit 6 determines whether the resistance value Rd of the first sensor 1 and the previous first reference value RdmO. Compare the size (S23), and if Rdm ⁇ Rd, the value obtained by multiplying the reference value RdmO at the previous update by subtracting the sensor resistance Rd from the reference value RdmO and multiplying by the specified update ratio. Is set to the new reference value Rdm (S24), and the update routine is terminated.
- the update ratio is 1ZCd (Cd> 1)
- the reference value R dm is expressed by the following equation.
- the reference value update unit 6 ends the update routine without updating the reference value.
- the reference value updating unit 6 prohibits updating the first reference summary Rdm on the first sensor side in the clean direction when the first contamination signal G becomes equal to or greater than the determination bell G3.
- the condition for canceling is that, after the first dirt signal (3 once becomes less than the judgment value G 4 «G3), the state less than the judgment value G 3 continues for a predetermined number of times of sampling.
- the reference value update unit 6 compares the size of the first dirt signal G and the determination bell G4 (S26), and if it is less than G4, the flag SSDRNW After 1 (S27), the process proceeds to step S29, and if it is G4 or more, the size of the first dirt signal G and the judgment bell G3 are compared (S28). If it is determined in S28 that the first dirt signal G is equal to or greater than the judgment value G3, the process proceeds to step S33. If the first dirt signal G is less than the judgment value G3, the flag SSDRNW is 1 or not. (S29).
- the counter value of the counter is reset to 0 (S33), and the processing routine is terminated.
- the value of flag SSDRNW is 1, predetermined sampling by the counter Judgment is made on whether or not the number of counts has been completed (S30). If the count has been completed, the prohibition of updating the reference value in the clean direction is canceled (S31), and the value of flag SSDRNW is set to 0. Later (S32), the process proceeds to step S23 to update the reference value. Note that if the count value has not reached the predetermined number of samplings as a result of the determination in S3 0, the processing routine is terminated.
- a routine for updating the first reference value Rgm on the second sensor side in the clean direction will be described based on the flowchart of FIG.
- the routine for updating the first reference bell Rgm in the cleaning direction is performed by performing the process of S14 in FIG. 5 before proceeding to this updating routine, so that the above-mentioned routine for updating the first reference ⁇ R dm in the cleaning direction is performed.
- the processing is the same as the update routine for the first reference value R dm except that the processing of S23 is eliminated, detailed description is omitted.
- the processing of this update routine is as follows.
- the reference value updating unit 6 sets a predetermined value after subtracting the reference value RgmO at the previous update from the sensor resistance Rg. Multiply the renewal ratio and add the reference value R gm ⁇ to set the value to the new reference value Rgm.
- the renewal ratio is IZCg (Cg> 1)
- the reference value Rgm is expressed by the following equation.
- the reference value updating unit 6 compares the sensor resistance Rd with the previous first reference value RdmO (S46). If Rd is RdmO, the previous first reference value RdmO is changed to the new reference value Rdm. After setting and finishing the update routine, if Rd RdmO, the previous first contamination signal D is compared with the predetermined judgment value D 5 (S47). In S47, the first dirt signal D is judged as D5.
- the value obtained by subtracting the first reference value RdmO from the sensor resistance Rd and multiplying the bell by the predetermined renewal ratio (1 Pd) is the renewal amount (2 (Rd—RdmO) / Pd) (S4 9)
- the constant Ld for adjusting the amount of renewal is set to the first dirt signal D by subtracting the first reference value RdmO from the sensor resistance Rd.
- the value multiplied by the bell (Ld / D) is used as the renewal amount (2 (Rd-RdmO) XL d / D) (S50).
- the reference value update unit 6 determines whether or not the update amount is 1 or more (S51). If it is 1 or more, the previous reference bell R dm ⁇ is set to S49 or S50. The value obtained by adding the calculated update amount is set as a new reference value R dm (S52), and if it is less than 1, the value obtained by adding 1 to the previous reference value Rdm 0 is the new value.
- the reference value is R dm. That is, if the first dirt signal D is less than the judgment value D5, the first reference value Rdm is expressed by the following formula (5). If the judgment value D is equal to or greater than 5, the first reference value R dm is It is expressed by 6). Note that Pd> 1 and Ld> 1.
- the new reference value Rgm is expressed by the following equation (7). If G5 or more, the new reference value Rgm is expressed by the following equation (8).
- Rgm RgmO- (RgmO-Rg) / Pg... (7)
- both gas determination units 4a and 4b determine the first reference values Rdm and Rgm determined by the above update routine from the resistance values Rd and Rg of the sensors 1 and 2 obtained by the equations (1) and (2).
- the sensitivity is normalized so that it does not depend on the sensor resistance bell that changes with temperature and humidity, and a correction factor is applied.
- the first fouling signal D which indicates the degree of air fouling due to exhaust gas from diesel vehicles
- the first fouling signal which indicates the degree of air fouling due to exhaust gas and odorous gas from gasoline vehicles.
- Kd is a correction coefficient (K d> 1) for correcting the variation between individuals of the first sensor 1
- Kg is a correction coefficient (Kg> 1) for correcting the variation between individuals of the second sensor 2.
- the first dirt signals D and G are expressed by the following equations.
- the first gas determination unit 4a compares the first contamination signal D with the predetermined determination values D1 and D2 (D1> D2), "1 When the dirt signal D is greater than or equal to the judgment value D1, the detection flag F DON is set to" 1 ", and when the first dirt signal D is lower than the judgment value D2, the detection flag FDON is set to" O ". (D dirt judgment routine S7).
- the second gas determination unit 4b compares the magnitude relationship between the first contamination signal G and the predetermined determination values G1, G2 (G 1> G2), When the first contamination signal G becomes equal to or greater than the judgment value G1, the value of the knowledge flag FGON is set to “1”, and when it becomes lower than the first contamination signal G judgment value G2, the detection flag FGON is set to “ ⁇ ” ( G dirt determination routine S18).
- each gas determination unit 4a, 4b outputs a gas detection signal when the first contamination signals D, G exceed a predetermined detection level (determination values D1, G1). Since hysteresis is provided in the output, the output can be prevented from fluttering.
- the value of the detection flag FDON input from the first gas determination unit 4a and the logic of the dust flag F GON input from the second gas determination unit 4b are displayed. If the value of at least one of the detection flags F DON and F GON is “1” (that is, one of the first dirt signals D and G is less than the detection level) If it exceeds, the control signal for switching to the introduction of the inside air (closing the damper) is output to the damper drive unit 21, and the damper drive unit 21 switches the tamper 20 to the inside air side in response to this control signal.
- the switching control unit 5 outputs a control signal for switching to open air introduction (opening the damper) to the damper drive unit 21 after the elapse of a predetermined time td, and the damper drive unit 21 receives the damper 20 on the outside air side in response to this control signal. Switch to.
- the reference value update unit 6 updates the first reference values R dm and R gm for each sensor according to the above update routine, and the car is in the city center, factory, sewage treatment plant, waste treatment plant, ranch. As the average gas concentration in the surrounding area gradually increases, the first reference value R dm increases, and the first reference value R gm increases. In urban areas, the amount of exhaust gas that may be said to be clean air is contained in air, or air that contains a minute amount of malodorous gas that the nose is used to and feels no odor. It can be prevented from being switched to the inside air side.
- the first reference value R dm decreases and the first reference value R gm increases accordingly.
- a small amount of exhaust gas and bad odor gas contained in clean air can be detected, the damper can be switched to the inside air side, and the standard of clean air according to changes in the surrounding environment
- the value can be set to perform damper control that matches the human sense. That is, the gas concentration when a person feels that the air is dirty due to a difference in location or the like is different, and the presence or absence of exhaust gas or odorous gas can be reliably detected using the first contamination signal.
- the reference value updating unit 6 sets the update cycle T for updating the first reference summary in the dirt direction as shown in FIG. 2 to a longer time than the update cycle t for updating in the clean direction.
- the renewal speed for updating in the dirt direction is slower than the renewal speed for updating the standard summary in the clean direction, so when the gas concentration changes in the dirt direction, the first reference bell changes slowly in the dirt direction.
- the tamper 20 can be switched to the inside air side.
- the first reference value can be changed in the clean direction in a short time. Therefore, a small amount of exhaust gas or malodorous gas in clean air is detected and tampering is detected. 20 can be switched to the inside air side.
- the above update ratios 1 ZP d and 1 ZC d shall be substantially the same value, and the update ratios 1 ZP g and 1 ZC g shall be substantially the same value.
- X represents the output Rd of the first sensor 1
- ⁇ represents the first reference value Rdm.
- the first sensor 1 having selectivity with respect to exhaust gas (oxidizing gas) of a diesel vehicle, and selectivity with respect to exhaust gas and malodorous gas (reducing gas) of a gasoline vehicle.
- the second sensor 2 is used, but the selectivity of both sensors 1 and 2 is not perfect, and the first sensor 1 has some sensitivity to the exhaust gas and odorous gas of gasoline cars.
- the second sensor 2 is also somewhat sensitive to diesel vehicle exhaust.
- the first reference value R for the first sensor 1 changes because the resistance value of the first sensor 1 decreases (cleaning direction) in an atmosphere with a high exhaust gas concentration or malodorous gas concentration discharged from the vehicle. If dm goes too far in the clean direction and then changes to a direction in which the resistance value of the first sensor 1 increases (dirt direction) when exposed to clean air, it is determined that there is exhaust gas from the diesel vehicle. Therefore, the damper 20 may be switched to the inside air side.
- the resistance value of the second sensor 2 changes in the direction of increasing (cleaning direction), so the first reference ⁇ R gm for the second sensor 2 Goes too clean, After that, when exposed to clean air and the resistance value of the second sensor 2 decreases (dirt direction), it is judged that there is exhaust gas or odorous gas from the gasoline car, and the damper 20 There is a possibility of switching to the side.
- the first sensor 1 detects even a slight amount of exhaust gas discharged from the diesel vehicle, and the first dirt signal D is the first. If the threshold level of 1 (judgment value D3) is exceeded, the reference value updater 6 prohibits the second sensor 2 from updating the reference value in the clean direction, so the exhaust gas emitted from the diesel vehicle is high.
- the output V g of the second sensor 2 increases in an environment that exists in the concentration, the first reference value on the second sensor side is prevented from going too far in the clean direction, and the surroundings return to a clean atmosphere. In addition, it is possible to prevent malfunctions in which the damper switches to the inside air side.
- the reference value update unit 6 prohibits the reference sensor 1 from being updated in the direction of cleanliness of the first sensor 1, the first value in an environment where exhaust gas or malodorous gas exhausted from a gasoline vehicle exists at a high concentration.
- the sensor 1 output V d decreases, preventing the first reference value on the first sensor side from going too far in the clean direction, and preventing the malfunction of the damper switching to the inside air when the surroundings return to a clean atmosphere. it can. Since the first and second threshold levels are provided with hysteresis (D3> D4, G3> G4), the operation for prohibiting the update of the reference value can be performed stably.
- the first reference values R dm and R gm are updated in the dirt direction
- the sensor resistance and the previous reference The update ratio applied to the difference with the value is inversely proportional to the magnitudes of the first dirt signals D and G, but this update ratio is 1 ZP d, 1 regardless of the magnitude of the first dirt signals D and G.
- ZP g is constant, the renewal amount is large ⁇ in an atmosphere with high exhaust gas concentration and bad odor gas concentration. Therefore, the first reference values R dm and R gm will change greatly in the direction of contamination when exposed to an atmosphere with high exhaust gas concentration and malodorous gas concentration for a long time. Dan / ⁇ ° 20 is outside even if the bottom just touches There is an union where dirty air flows in.
- the update ratio is set to the value of the first dirt signals D and G. Since the values (LdZD) and (Lg / G) are inversely proportional to the magnitude, the update value of the first reference values R dm and Rgm can be made inversely proportional to the magnitude of the first contamination signals D and G.
- the gas gas concentration or malodorous gas concentration becomes high (that is, when the first contamination signal D, G becomes large)
- the update amount of the first reference value Rdm, Rgm is decreased, and the first reference value Rdm
- the update speed of Rgm in the dirt direction can be delayed.
- the first standard ⁇ Rdm, Rgm can be delayed from changing in the direction of contamination, and the exhaust gas concentration or malodorous gas concentration can be reduced. It is possible to prevent the damper 20 from switching to the outside air just by lowering slightly.
- the update speed t for updating the first reference value in the cleaning direction is shorter than the update period T for updating the dirt direction, so that the update speed of the first reference value in the cleaning direction is reduced.
- the update rate is faster than the update rate in the dirt direction, but the update cycle T and update cycle t are approximately the same cycle, and the update ratio is 1 Pd, 1 ZPg when the first reference rod is updated in the dirt direction.
- the renewal ratio 1 / Cd, 1 ZCg to a large value (that is, Pd> Cd> 1, Pg> Cg> 1) when the first reference value is updated in the cleaning direction, Compared to updating the value, the update rate when updating the first reference value in the clean direction can be increased, and the same effect as described above can be obtained.
- the gas detection device A outputs a switching signal for closing and closing the damper to the damper closing device, but outputs the first dirt signals D and G as they are, and the vehicle air conditioner
- the damper opening / closing control may be performed using a main computer or the like.
- one sensor detects both exhaust gas and bad odor gas from a gasoline vehicle.
- a sensor that is particularly sensitive to exhaust gas from a gasoline vehicle and the output of this sensor.
- a gas determination unit for detecting the exhaust gas of a gasoline car from A sensor that is particularly sensitive to malodorous gas and a gas determination unit that detects malodorous gas from the output of this sensor are provided separately, and the reference value update unit 6 updates the reference bell of each gas determination unit You may do it.
- the first sensor 1 since the first sensor 1 is sensitive to the exhaust gas or bad odor gas (reducing gas) discharged from the gasoline vehicle, the exhaust gas concentration or bad odor gas of the gasoline vehicle is used. In an atmosphere with a high concentration, the resistance value of the first sensor 1 changes in the direction of decreasing (cleaning direction).
- the second sensor 2 since the second sensor 2 is also sensitive to exhaust gas (oxidizing gas) emitted from diesel vehicles, the second sensor 2 is used in an atmosphere where the exhaust gas concentration of the diesel vehicle is high. Changes in the direction of increasing the resistance value (cleaning direction).
- the judgment values D 1, D 2, G 1, G, and the like can be detected so that the exhaust gas or the malodorous gas having a relatively low concentration can be detected and the damper 20 can be switched to the inside air side.
- 2 is set to a very small value, if the reference value goes too far in the clean direction due to fluctuations in sensor output due to interference gas, the surroundings will return to a clean environment, and there will be no influence from interference gas.
- the judgment values D1, D2, G1, and G2 are set to very large values, it will not only be possible to detect low-concentration exhaust gases or odorous gases.
- the answering time until the damper 20 is switched becomes longer and varies. In some cases, the judgment value is not reached, and the damper 20 remains switched to the outside air side.
- FIG. 10 is a block diagram of the present embodiment.
- This gas detection apparatus A includes a first sensor 1, a second sensor 2, / 0 converters 3 &, 3 b, 1 gas determination unit 4a, second gas determination unit 4b, first low-concentration gas determination unit 4c, second low-concentration gas determination unit 4d, switching control unit 5, and reference lamp update Unit 6 and sensor drive unit 7 as main components.
- a / D converters 3a and 3b, determination units 4a to 4d, switching control unit 5, reference bar update unit 6, and sensor drive unit 7 Is built using a microcomputer with a built-in AZD converter. Since the configuration other than the first and second low-concentration gas determination units 4c and 4d is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted. To do.
- the first and second low-concentration gas determination units 4 c and 4 d are connected to the sensor outputs V g and Vd input from the AZD converters 3 a and 3 b in the same manner as the gas determination units 4 a and 4 b described above. Based on the above, find the resistance values Rd and Rg of each sensor 1 and 2.
- each low-concentration gas determination unit 4c, 4d obtains a value obtained by subtracting the second reference value Rdm2, Rgm2 set for each sensor from the resistance value Rd, Rg of each sensor 1, 2, and the second reference value Rdm2, By dividing by Rgm2 and obtaining the resistance ratio, the sensitivity is standardized so that it does not depend on the sensor resistance value that varies with temperature and humidity, and by applying a correction coefficient, variations in sensitivity among individual sensors are corrected.
- the second dirt signal D02 which represents the degree of air pollution caused by exhaust gas from diesel vehicles
- the second dirt signal GO2 which represents the degree of air dirt caused by exhaust gas and odorous gas from gasoline cars, respectively. Convert.
- Kd 2 is a correction coefficient (Kd2> 1) for correcting the variation between individuals of the first sensor 1
- Kg 2 is a correction coefficient (Kg2> 1 for correcting the variation between individuals of the second sensor 2.
- the second contamination signal D02, G02 is expressed by the following equation.
- G02 (Rgm2-Rg) XKg2 / Rgm2
- the second reference values Rdm2, R gm2 used when the first and second low concentration gas determination units 4c, 4d obtain the second contamination signals D02, G02 are the first reference values R dm, Rgm
- the reference value update unit 6 appropriately updates.
- the update routine of the second reference values Rdm2 and R gm2 by the reference value update unit 6 is described in the first embodiment. This is substantially the same as the first reference value Rdm, Rgm update routine, and a detailed description thereof will be omitted.
- the update process of the second reference bell Rdm2, Rgm2 is briefly explained.
- the resistances Rd, Rg of both sensors 1, 2 sampled this time are used as the second reference value Rdm02 at the previous update.
- Rgm02 is multiplied by a predetermined update ratio ( ⁇ 1) and the reference values RdmO 2 and Rgm02 at the previous update are added to obtain the second reference values Rdm2 and Rgm2.
- the second reference values Rdm2 and Rgm2 are determined by the following equation.
- Rdm2 Rdm02 + (Rd— Rdm02) / Pd2
- the second reference values Rdm2 and Rgm2 are determined by the following equations.
- Rdm2 Rdm02 + (Rd-Rdm02) / Cd2
- Rgm2 Rgm02 + (Rg— Rgm ⁇ 2) / Cg2
- the first low-concentration gas determination unit 4c compares the magnitude relationship between the second contamination signal D02 and the predetermined determination value D12, If the dirt signal DO2 is greater than or equal to the judgment value D12, the detection flag FDON ⁇ is set to “1” for a certain period of time Td2.
- the second low-concentration gas determination unit 4d the first Similar to the low-concentration gas determination unit 4c, compare the magnitude relationship between the second contamination signal GO 2 and the predetermined determination value G12. If the contamination signal G ⁇ 2 is equal to or greater than the determination value G12, it is detected for a certain time Tg 2. Set ⁇ of flag FGON to “1”.
- Fig. 11 is a flowchart of a control routine for controlling the opening and closing of the damper 20.
- the switching control unit 5 determines whether or not the values of the detection flags FDOON and FGON are both 0 (S62, 2). S63). If either of the detection flags FDOON and FGON is 1, a control signal for switching to introduction of the inside air (closing the damper) is output to the damper drive unit 21 (S69), and the process proceeds to step S700.
- the switching control unit 5 determines whether or not the value of the flag DLYO FF indicating the hold period is 1 (S64), and the value of the flag DLYOFF is 0. If there is, the process proceeds to step S68. If the flag DL ⁇ ⁇ FF is ⁇ , it is determined whether the predetermined hold time Tw3 is counted or not (S65). If the count is not completed in S65, the process proceeds to S69 and the damper 20 is kept closed. If the count is completed in S65, the flag indicating that the hold period is in progress.
- step S end 0 it is determined whether or not the value of the flag D LYON is 1, and if the flag D LYON is 1, it is determined whether or not the counting of the predetermined stop time Tm has ended ( S71), the flag D LYON is set to ⁇ when the stop time counting ends, and the detection flags FD ⁇ N and FGON from the first and second low-concentration gas judgment units 4c and 4d are made valid. (S end 2).
- the reference value update unit 6 moves the second reference value Rdm2,
- the update cycle T 2 for updating Rgm 2 is set to a time longer than the update cycle t 2 for updating the second reference values Rdm2 and Rgm2 in the clean direction and shorter than the update cycle T, and further the update cycle Since t 2 is set to a time shorter than the update period t and equal to or longer than the sampling period ts (ts ⁇ t 2 ⁇ T 2 ⁇ T, t 2 ⁇ t), gas
- the second reference values Rdm2 and Rgm2 when the concentration changes in the dirt direction can be changed in a short time compared to the first reference values Rdm and Rgm, and the judgment bells D12 and G12 are reduced by a corresponding amount.
- one set of the first low-concentration gas determination unit 4c and the second low-concentration gas determination unit 4d is updated in a shorter time than the first reference value used by the first gas judgment unit 4a and the second gas judgment unit 4b of the other set, so It is possible to detect a change in gas concentration in a short time and switch the damper 20, but as a result, the number of switching of the damper 20 increases.
- An increase in the number of switching of the damper 20 is not preferable for the life of the motor that drives the damper 20, and a signal for switching from the outside air side to the inside air side may be issued immediately after the damper 20 is switched from the inside air side to the outside air side.
- a reverse drive signal is input while the motor is rotating in one direction, it is not preferable for the life of the motor.
- the switching operation of the damper 20 may take several seconds (about 7 seconds), and while the damper 20 is performing the switching operation, some may not accept a new switching signal. It is not preferable to issue a switching signal for switching the damper 20 to the outside air side when switching signals for switching to the side are issued one after another.
- the switching control unit 5 sets the dust flag FDOON and FGON. Even if both values become “0” (that is, even when exhaust gas or bad odor gas is not detected), the control signal for switching the damper 20 to the inside air is still output and the built-in Tw3 A timer (not shown) is operated, and the damper 20 is kept switched to the inside air while the built-in timer is counting. If the detection flag FDON or FGON becomes “1” while the built-in timer is counting (that is, if exhaust gas or odorous gas is detected), the switching control unit 5 resets the built-in timer, and then detects the flag FD ⁇ N.
- the switching control unit 5 switches the damper 20 to the outside air side when the detection flags FDOON and FGON are both “0” (that is, exhaust gas and odorous gas are not detected), or If the built-in timer counts up while the detection flag FD ⁇ N and FGON remain ⁇ O '' while the built-in timer keeps counting, when the damper 20 is switched to the outside side, the damper 20 is placed on the outside side. While the specified stop time of Tm seconds has elapsed since the switch to, the flag DLYON is set to 1, and the detection flags FD ⁇ N and FGON from the first and second low-concentration gas determination units 4c and 4d are disabled.
- the first and second low concentration gas determination units 4c and 4d are added, and the first and second gas determination units 4a and 4b are added.
- the switching control unit 5 performs switching control of the damper 20 based on the determination results of the first and second low-concentration gas determination units 4c and 4d.
- the first and second low concentration gas determination units 4 c and 4 d of the present embodiment are provided instead of the first and second gas determination units 4 a and 4 b, and the first and second low gas determination units 4 a and 4 b are provided.
- the switching control unit 5 may perform switching control of the damper 20 based on the determination results of the concentration gas determination units 4 c and 4 d.
- the sensor 1 having a relatively large sensitivity in the direction in which the resistance value decreases with respect to the exhaust gas or malodorous gas of the gasoline vehicle is used as the first sensor 1, for example, the exhaust gas of the gasoline vehicle When exposed to exhaust gas or odorous gas from a gasoline car for a long time, such as when going out of a contaminated tunnel, the resistance of the first sensor 1 rises and The low-concentration gas judgment unit 1c of 1 may erroneously judge this change in resistance value if diesel vehicle exhaust gas exists.
- the predetermined determination value G 6 and G end are set in the second gas determination unit 4 b, and the first contamination signal G becomes equal to or greater than the determination value G 6.
- the dirt determination in the first low-concentration gas determination unit 4c is stopped until the determination value G7 becomes smaller than the determination value G7. During this period, the determination in the first low-concentration gas determination unit 4c is stopped. It is possible to prevent erroneous detection of a change in resistance of the first sensor 1 due to interference gas.
- hysteresis is provided at the determination stop level (determination values G6 and G7) when stopping the determination of the first low-concentration gas determination unit 4c.
- the concentration gas determination unit 4c can be operated stably. Industrial applicability
- the update amount is obtained by multiplying the difference between the current sensor output and the first reference value at the previous update by the update ratio. Since the first reference value of this time is obtained by adding the amount to the first reference value at the time of the previous update, the first reference value can be changed according to the surrounding environment. Even if the gas concentration is different when people feel it is dirty, the exhaust gas The presence or absence of a bad odor gas can be reliably detected.
- the first dirt signal of this gas detection device to control the switching of the car's damper, it fits the human senses in any environment and takes in the outside air when the outside air is clean, When the outside air is dirty, the inside air can be circulated to keep the passenger compartment air clean.
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Abstract
Description
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AU2003262028A AU2003262028A1 (en) | 2003-09-09 | 2003-09-09 | Gas detector |
PCT/JP2003/011526 WO2005026712A1 (ja) | 2003-09-09 | 2003-09-09 | ガス検出装置 |
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Cited By (3)
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JP2010008326A (ja) * | 2008-06-30 | 2010-01-14 | Yamatake Corp | 湿度計測装置 |
JP2011052977A (ja) * | 2009-08-31 | 2011-03-17 | Yazaki Corp | ガス検出装置 |
EP3549801A4 (en) * | 2016-12-02 | 2019-12-11 | Denso Corporation | VEHICLE CLIMATE CONTROL DEVICE |
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- 2003-09-09 JP JP2005508900A patent/JP4074634B2/ja not_active Expired - Fee Related
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JPH05294132A (ja) * | 1992-04-17 | 1993-11-09 | Zexel Corp | 車両用空気汚染度検出装置 |
WO1995029435A1 (en) * | 1994-04-27 | 1995-11-02 | Auto Electronics Corporation | Sensor system for controlling ventilation systems in vehicles |
WO1996035115A1 (de) * | 1995-04-29 | 1996-11-07 | I.T.V.I. International Techno Venture Invest Aktiengesellschaft | Sensoranordnung zur steuerung der belüftung von innenräumen |
JPH1142925A (ja) * | 1997-07-25 | 1999-02-16 | Denso Corp | 車両用空調装置 |
JPH11240323A (ja) * | 1998-02-25 | 1999-09-07 | Denso Corp | 車両用空調装置 |
JP2003057202A (ja) * | 2001-08-09 | 2003-02-26 | Ngk Spark Plug Co Ltd | ガス検出装置、車両用オートベンチレーションシステム |
JP2003098138A (ja) * | 2001-09-27 | 2003-04-03 | Ngk Spark Plug Co Ltd | ガス検知装置、車両用オートベンチレーションシステム |
JP2003121400A (ja) * | 2001-10-12 | 2003-04-23 | Ngk Spark Plug Co Ltd | ガス検出装置、車両用オートベンチレーションシステム |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010008326A (ja) * | 2008-06-30 | 2010-01-14 | Yamatake Corp | 湿度計測装置 |
JP2011052977A (ja) * | 2009-08-31 | 2011-03-17 | Yazaki Corp | ガス検出装置 |
EP3549801A4 (en) * | 2016-12-02 | 2019-12-11 | Denso Corporation | VEHICLE CLIMATE CONTROL DEVICE |
Also Published As
Publication number | Publication date |
---|---|
AU2003262028A1 (en) | 2005-04-06 |
JP4074634B2 (ja) | 2008-04-09 |
JPWO2005026712A1 (ja) | 2006-11-24 |
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