JP2008190889A - Gas sensor system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the gas sensor system mounted on a vehicle to detect a gas to be detected, such as hydrogen, that operates corresponding to the state of the vehicle and can prevent deterioration of a gas-detecting element. <P>SOLUTION: The gas sensor system 1 mounted on a fuel cell vehicle and operated corresponding to the vehicle to detect hydrogen is equipped with: the gas-detecting element 23 for detecting hydrogen; a first gas detection chamber 32 having the gas-detecting element 23 arranged therein and taking in hydrogen; a second detection chamber 41; a butterfly valve 51 capable of holding the first and the second gas detection chambers 32 and 41 to a hermetically sealed state; and an ECU 90 for controlling the butterfly valve 51 to determine whether the fuel cell vehicle is stopped. When the fuel cell vehicle is determined as having stopped, the ECU 90 hermetically seals the first and second gas detection chambers 32 and 41 using the butterfly valve 51. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas sensor system.

  A solid polymer type fuel cell forms an MEA (Membrane Electrode Assembly) by sandwiching both sides of a solid polymer membrane between an anode (fuel electrode) and a cathode (oxygen electrode), and this membrane electrode assembly A single fuel cell stack is formed by stacking a plurality of single cells sandwiched between a pair of separators. Then, hydrogen (fuel gas) is supplied to the anode, and air (oxidant gas) is supplied to the cathode. An electrode reaction occurs at the anode and the cathode, and the fuel cell generates power.

  Since unreacted hydrogen (detected gas) is discharged from such a fuel cell, a hydrogen sensor is provided in the flow path of the off gas discharged from the fuel cell, and the hydrogen sensor detects the hydrogen concentration in the off gas. It is being monitored. The off gas contains water vapor (moisture) generated by the electrode reaction and is humid.

  However, when a gas detection element that is built in a hydrogen sensor and detects hydrogen by a gas catalytic combustion method or the like is exposed to water vapor in off-gas for a long period of time, it deteriorates. In view of this, for example, a gas sensor is disclosed in which a valve body that appropriately blocks intrusion of a gas to be detected is provided and the valve body is operated by a coil spring made of a shape memory alloy that expands and contracts depending on temperature (see Patent Document 1).

The fuel cell system including the fuel cell is mounted on, for example, a fuel cell vehicle (vehicle). The operation of the fuel cell system, that is, whether the fuel cell is in the power generation state or the non-power generation state is usually synchronized with the state of the fuel cell vehicle (for example, running or stopped).
Japanese Utility Model Publication No. 3-40553

  As described above, when the fuel cell and its system are mounted on a fuel cell vehicle, a hydrogen sensor is also mounted. When the hydrogen sensor is mounted on the fuel cell vehicle as described above, it is considered preferable that the hydrogen sensor is interlocked with the state of the fuel cell vehicle, but this is not disclosed in Patent Document 1.

  Therefore, the present invention provides a gas sensor system that is mounted on a vehicle and detects a gas to be detected such as hydrogen and that operates according to the state of the vehicle and can prevent deterioration of the gas detection element. Let it be an issue.

  As means for solving the above-mentioned problems, the present invention is a gas sensor system that is mounted on a vehicle, operates in accordance with the state of the vehicle (for example, running state, stopped state), and detects a gas to be detected. A gas detection element for detecting the gas to be detected; a gas detection chamber in which the gas detection element is disposed; a gas detection chamber into which the gas to be detected is taken; a valve mechanism capable of maintaining the gas detection chamber in a sealed state; A valve mechanism control unit that controls the valve mechanism; and a stop determination unit that determines whether or not the vehicle has stopped. When the stop determination unit determines that the vehicle has stopped, the valve mechanism control unit The gas sensor system is characterized in that the means seals the gas detection chamber by the valve mechanism.

  According to such a gas sensor system, when it is determined by the stop determination means that the vehicle has stopped, the valve mechanism control means seals the gas detection chamber by the valve mechanism correspondingly. As a result, factors (deterioration factors) that degrade the gas detection element such as water vapor (moisture) and dust do not enter the gas chamber while the vehicle is stopped. As a result, it is possible to prevent the gas detection element from being deteriorated due to the deterioration factor.

  In addition, scavenging means for introducing a scavenging gas into the gas detection chamber and scavenging the gas detection chamber is provided. When the stop determination means determines that the vehicle has stopped, the scavenging means opens the gas detection chamber. After the scavenging, the valve mechanism control means is preferably a gas sensor system that seals the gas detection chamber by the valve mechanism.

  Here, scavenging means that deterioration factors such as water vapor and dust are pushed out of the gas detection chamber and discharged by the scavenging gas. The scavenging gas refers to a gas that is used for such scavenging and does not include the deterioration factor or includes a small amount of the deterioration factor. For example, as described in an embodiment described later, air (outside air) is used. Can be used.

  According to such a gas sensor system, when it is determined by the stop determination means that the vehicle has stopped, after the gas detection chamber is scavenged by the scavenging means, the valve mechanism control means seals the gas detection chamber by the valve mechanism. That is, since the gas detection chamber is sealed after reducing the amount of the deterioration factor in the gas detection chamber, it is possible to more suitably prevent the gas detection element from deteriorating while the vehicle is stopped after the sealing.

  A humidity sensor for detecting the humidity of the gas detection chamber; and a scavenging gas amount determining means for determining the amount of the scavenging gas based on the humidity of the gas detection chamber, wherein the humidity of the gas detection chamber is It is preferable that the gas sensor system has a higher amount of scavenging gas as it is higher.

  According to such a gas sensor system, as the humidity of the gas detection chamber is higher, the scavenging gas amount is determined by the scavenging gas amount determination means. Since the gas detection chamber is scavenged by the determined amount of scavenging gas, the humidity of the gas detection chamber can be appropriately reduced. Thereby, after the gas detection chamber is sealed, deterioration of the gas detection element due to water vapor (moisture) can be suitably prevented.

  Preferably, the gas detection system includes a temperature sensor that detects the temperature of the gas detection chamber, and the scavenging means is a gas sensor system that continues scavenging until the temperature of the gas detection chamber becomes a predetermined temperature or lower.

  According to such a gas sensor system, since the scavenging is continued until the temperature of the gas detection chamber becomes equal to or lower than a predetermined temperature at which the gas detection element is not thermally deteriorated, the gas detection is performed while scavenging the gas detection chamber. After the chamber temperature is lowered, the gas detection chamber can be sealed. That is, the gas detection chamber is prevented from being sealed at a high temperature, and as a result, thermal deterioration of the gas detection element can be prevented.

  In addition, a scavenging gas amount determining means for determining the amount of the scavenging gas based on the concentration of the gas to be detected in the gas detection chamber is provided, and the amount of the scavenging gas increases as the concentration of the gas to be detected increases. A gas sensor system is preferred.

  According to such a gas sensor system, the higher the concentration of the gas to be detected in the gas detection chamber, the higher the scavenging gas amount is determined by the scavenging gas amount determining means, and the gas detection is performed by the determined amount of scavenging gas. Since the chamber is scavenged, the concentration of the gas to be detected in the gas detection chamber can be appropriately reduced. Thereby, it is possible to suitably prevent the gas detection element from being deteriorated by a high concentration of the gas to be detected.

  According to the present invention, there is provided a gas sensor system that is mounted on a vehicle and detects a gas to be detected such as hydrogen and that operates according to the state of the vehicle and can prevent deterioration of the gas detection element. it can.

<< First Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
The gas sensor system 1 according to the first embodiment is a system incorporated in a fuel cell system, and is installed in a fuel cell automobile (vehicle) together with the fuel cell system. The gas sensor system 1 is interlocked with an ON / OFF signal (vehicle state) of the IG 61 that is a start switch of the fuel cell system (fuel cell vehicle).

≪Configuration of gas sensor system≫
The gas sensor system 1 includes an offgas pipe 10 through which offgas discharged from a polymer electrolyte fuel cell (not shown) flows, a hydrogen sensor 20 that detects a hydrogen concentration in the offgas, and a first gas detection chamber of the hydrogen sensor 20. 32 and the second gas detection chamber 41 (referred to as the second gas detection chamber 41 etc.), the scavenging means 60 for sending the scavenging gas into the second gas detection chamber 41 etc., and the second gas detection chamber 41. A humidity sensor 71 that detects humidity such as IG81 and an ECU 90 (Electronic Control Unit) are mainly provided.

<Obgas piping>
The offgas pipe 10 is connected downstream of the fuel cell so that offgas flows. A through hole 11 serving as an off gas passage is formed in the upper wall of the off gas pipe 10.
In order to secure the solid polymer membrane constituting the fuel cell in a wet state, the fuel cell is supplied with humidified hydrogen or air, and the fuel cell generates water (water vapor) by power generation. The off gas is humid. Incidentally, the off-gas may be any of an anode off-gas discharged from the anode of the fuel cell, a cathode off-gas discharged from the cathode, and a mixture thereof.

<Hydrogen sensor>
The hydrogen sensor 20 includes a substrate 21 on which a sensor circuit is patterned, a case 22 that houses the substrate 21, a gas detection element 23 that is connected to the substrate 21 and protrudes downward from the lower surface of the case 22. And an element accommodating portion 30 that accommodates the gas detecting element 23.
The case 22 is fixed to a second element accommodating portion 40, which will be described later, by a bolt (not shown), and the second element accommodating portion 40 is fixed to the off-gas pipe 10 by a bolt (not shown).

  The gas detection element 23 is disposed in a first gas detection chamber 32 which will be described later, and is an element that detects the hydrogen concentration C11 in the off-gas taken into the first gas detection chamber 32. The gas detection element 23 outputs an electrical signal to the substrate 21 in accordance with the detected hydrogen concentration C11. The substrate 21 includes a CPU, a ROM, a RAM, various interfaces, an electronic circuit, and the like, calculates a hydrogen concentration C11 based on an electric signal from the gas detection element 23, and outputs the hydrogen concentration C11 to the ECU 90. ing.

The type and number of gas detection elements 23 are determined according to the detection method of the hydrogen concentration C11.
For example, when the hydrogen detection method is a gas catalytic combustion type, the gas detection element 23 is configured by a pair of a detection element and a temperature compensation element. And hydrogen concentration C11 is detected based on the electrical resistance difference between a detection element and a temperature compensation element using the heat generated when hydrogen contacts each element and burns.
Further, when the hydrogen detection method is a semiconductor method, the gas detection element 23 is configured by a pair of a detection element and a detection element. Then, the hydrogen concentration C11 is detected based on a resistance value generated when hydrogen comes into contact with or leaves oxygen from the surface of each element.
Further, when the hydrogen detection method is a heat conduction method, the gas detection element 23 (hydrogen detection unit) is configured by a pair of a heater for heating hydrogen and a temperature sensor. The hydrogen concentration C11 is detected based on the fact that hydrogen has a higher thermal conductivity than other gases.

  The element accommodating portion 30 is a housing that surrounds and accommodates the gas detection elements 23 in a double manner, and mainly includes an inner first element accommodating portion 31 and an outer second element accommodating portion 40.

  The first element housing portion 31 is a substantially bottomed cylindrical body projecting from the lower surface of the case 22 and has a first gas detection chamber 32 therein. A gas flow hole 33 is formed in the bottom wall of the first element housing portion 31, and a filter 34 is provided so as to cover the gas flow hole 33. The filter 34 is a filter that allows gas (gas) to flow while ensuring explosion-proof properties, and is configured by, for example, a layered structure of a water-repellent filter and an explosion-proof filter. The water repellent filter is a filter that transmits gas but does not transmit liquid contained in gas, and is made of, for example, a tetrafluoroethylene film. The explosion-proof filter is a filter for ensuring explosion-proof properties, and is made of, for example, a metal mesh or a porous body that allows liquid water to pass through.

  The second element housing part 40 is a substantially cylindrical body provided outside the first element housing part 31, and has a second gas detection chamber 41 inside thereof. The second gas detection chamber 41 communicates with the first gas detection chamber 32 through the filter 34 and the off-gas pipe through the through hole 11. Further, a through hole 42 serving as a scavenging gas passage is formed in the peripheral wall of the second element housing portion 40.

<Butterfly valve>
The butterfly valve 51 is a valve body that is actuated by an actuator (not shown) (for example, an ultrasonic motor, a solenoid) (see arrow A1) and that can maintain the second gas detection chamber 41 and the like in a sealed state. 40. However, the gate valve, the ball valve, the globe valve, and the like may be used as long as the second gas detection chamber 41 and the like can be maintained in a sealed state without being limited to the butterfly valve 51. When an ultrasonic motor is used as the actuator, the butterfly valve 51 can be maintained in the open position or the closed position by the static torque in the non-energized state, and power consumption can be suppressed.

The actuator is connected to the ECU 90 and operates in accordance with a command from the ECU 90. As a result, the butterfly valve 51 opens and closes. Therefore, in the first embodiment, the valve mechanism capable of maintaining the second gas detection chamber 41 and the like in a sealed state includes the butterfly valve 51 and the actuator.
The actuator and the compressor 61, which will be described later, are powered by a fuel cell, a battery (power storage device), or the like.

<Scavenging means>
The scavenging means 60 is a means for introducing a scavenging gas into the second gas detection chamber 41 and the like and scavenging the second gas detection chamber 41 and the like, and mainly includes a compressor 61 and an on-off valve 62. The compressor 61 is connected to the through hole 42 of the second element housing portion 40 via a pipe 61a, an on-off valve 62, and a pipe 62a. In response to a command from the ECU 90, the on-off valve 62 is opened, and when the compressor 61 is operated, outside air is taken in and sent to the first gas detection chamber 32, the second gas detection chamber 41, and the like as scavenging gas.

  Since the on-off valve 62 allows the scavenging gas to flow into the second gas detection chamber 41 or the like only during scavenging, a check valve may be provided instead of this, for example. If the check valve is used in this way, control by the ECU 90 becomes unnecessary. The compressor 61 may also serve as a compressor that sends air to the fuel cell, or may use a blower (fan), for example, instead of the compressor 61.

<Humidity sensor>
The humidity sensor 71 is disposed in the second gas detection chamber 41, detects the humidity H11 of the second gas detection chamber 41, etc., and outputs it to the ECU 90. In addition, the position of the humidity sensor 71 is not limited to this, You may provide in the 1st gas detection chamber 32, and may provide in both.

<IG>
The IG 81 is a start switch for the fuel cell vehicle and the fuel cell system, and is provided around the driver's seat. Further, the IG 81 is connected to the ECU 90, and the ECU 90 detects an ON / OFF signal of the IG 81.

<ECU>
The ECU 90 is a control device that electronically controls a fuel cell system (fuel cell vehicle) including the gas sensor system 1 and includes a CPU, a ROM, a RAM, various interfaces, an electronic circuit, and the like.
When the ECU 90 detects the ON signal of the IG 81, the ECU 90 supplies hydrogen and oxygen-containing air to the fuel cell to generate power and run the fuel cell vehicle according to the driver's request. ing. That is, the ECU 90 (stop determination means) has a function of determining that the fuel cell vehicle has stopped when the IG 81 detects an OFF signal.

  The ECU 90 (valve mechanism control means) has a function of appropriately controlling the butterfly valve 51, the compressor 61, and the on-off valve 62.

Further, when the ECU 90 (scavenging gas amount determining means) determines that the fuel cell vehicle has stopped, scavenging is performed based on the humidity H11 detected by the humidity sensor 71 and the map shown in FIG. 3 stored therein. A function of determining the total amount of gas and the operation time of the compressor 61 is provided.
The map shown in FIG. 3 is a graph that is obtained by a preliminary test or the like and shows the relationship between the humidity H11 and the total amount of scavenging gas (the operation time of the compressor 61). The operating time of the compressor 61 tends to be longer as the number of compressors 61 increases. However, the map shown in FIG. 3 illustrates the case where the compressor 61 is operated at a constant rotational speed.

≪Operation of gas sensor system≫
Next, the operation of the gas sensor system 1 will be described together with the flow of a program (flowchart) set in the ECU 90 with reference mainly to FIG. In the initial (start) state of FIG. 2, the IG 81 is in the ON state, the fuel cell system is activated (the fuel cell is generating power), and the fuel cell vehicle is in the running or idling state. In the initial state, the butterfly valve 51 is open and the on-off valve 62 is closed.

In step S101, the ECU 90 determines whether or not the fuel cell vehicle has stopped based on whether or not the IG 81 is turned off. When it is determined that the IG 81 is turned off and the fuel cell vehicle has stopped (S101, Yes), the processing of the ECU 90 proceeds to step S102. On the other hand, when it is determined that the IG 81 is not turned OFF and the fuel cell vehicle is not stopped (No in S101), the determination in step S101 is repeated.
Note that when the IG 81 is turned off, the ECU 90 stops the supply of hydrogen and air to the fuel cell and stops the power generation of the fuel cell. Thereby, the hydrogen concentration in the off-gas discharged from the fuel cell gradually decreases.

  In step S102, the ECU 90 detects the current humidity H11 of the second gas detection chamber 41 and the like via the humidity sensor 71.

  In step S103, the ECU 90 calculates and determines the total amount of scavenging gas to be sent to the second gas detection chamber 41 and the like based on the humidity H11 detected in step S102 and the map of FIG.

In step S104, the ECU 90 determines the operating time of the compressor 61 based on the total amount of scavenging gas calculated in step S103. Here, in the first embodiment, the case where the compressor 61 is operated at a constant rotational speed is exemplified, so that the higher the humidity H11 and the greater the total amount of scavenging gas, the longer the operation time of the compressor 61 (see FIG. 3). ).
However, the present invention is not limited to this, and a configuration may be adopted in which the rotational speed of the compressor 61 is increased when the total amount of scavenging gas increases.

In step S105, the ECU 90 opens the butterfly valve 51 and the on-off valve 62, and operates the compressor 61 for the operation time determined in step S105. Thereby, scavenging gas is sent into the 2nd gas detection chamber 41 grade | etc., Scavenging is implemented, and the humidity H11 of the 1st gas detection chamber 32 and the 2nd gas detection chamber 41 falls.
Then, after the operation time has elapsed, the ECU 90 stops the compressor 61.

In step S106 after scavenging the second gas detection chamber 41 and the like, the ECU 90 closes the butterfly valve 51 and the on-off valve 62. As a result, the second gas detection chamber 41 and the like are sealed.
Then, the processing of the ECU 90 proceeds to the end, and the operation of the gas sensor system 1 ends.

≪Effect of gas sensor system≫
According to such a gas sensor system 1, the following effects can be mainly obtained.
When the fuel cell vehicle (fuel cell system) is stopped and the hydrogen concentration C11 in the off-gas decreases and it is not necessary to detect the hydrogen concentration C11, the first gas detection chamber 32 and the second gas detection are detected by the butterfly valve 51 or the like. The chamber 41 can be maintained in a sealed state. Thereby, while the fuel cell vehicle is stopped, deterioration factors such as off gas and water vapor and dust accompanying the off gas do not enter the first gas detection chamber 32 and the second gas detection chamber 41. Therefore, the gas detection element 23 is not exposed to water vapor, dust or the like while the fuel cell vehicle is stopped, and deterioration of the gas detection element 23 due to water vapor, dust or the like is prevented.

  Further, before sealing the second gas detection chamber 41 etc., the scavenging gas scavenges the second gas detection chamber 41 etc. and lowers the humidity H11 of the second gas detection chamber 41 etc. The second gas detection chamber 41 and the like can be sealed after the environment is reduced. Thereby, deterioration of the gas detection element 23 can be suitably prevented.

  Furthermore, the total amount of the scavenging gas sent into the second gas detection chamber 41 or the like is appropriately determined based on the humidity H11 when the IG 81 is OFF. Thereby, the 2nd gas detection chamber 41 grade | etc., Can be scavenged suitably, and the humidity H11 can be lowered | hung.

Thus, in the first embodiment, in the initial state where the butterfly valve 51 is open (IG81 is ON), when the IG81 is turned OFF, the butterfly valve 51 is closed and the fuel cell vehicle continues to be stopped. However, a case where the butterfly valve 51 is opened will be described.
The ECU 90 opens the butterfly valve 51 when the IG 81 is actually turned on (when entering the ON position) or when the IG 81 is expected to be turned on thereafter. When the IG81 is expected to be turned on, for example, when it is detected that the key is inserted into the cylinder, when the passenger is detected in the vehicle by the passenger sensor, the seating of the driver is detected by the seating sensor. In this case, it is detected that the door on the driver's seat side is opened, and that the door lock is unlocked.

<< Second Embodiment >>
Next, the second embodiment of the present invention will be described with reference to FIG. 4 and FIG.

≪Configuration of gas sensor system≫
As shown in FIG. 4, the gas sensor system 2 according to the second embodiment includes a temperature sensor 72 instead of the humidity sensor 71 (see FIG. 1). The temperature sensor 72 is arranged in the second gas detection chamber 41, detects the current temperature T11 of the second gas detection chamber 41, etc., and outputs the detected temperature T11 to the ECU 90. Note that the temperature sensor 72 may be provided in the first gas detection chamber 32.

  The ECU 90 according to the second embodiment has a function of starting scavenging after the fuel cell vehicle stops, and continuing this scavenging until the temperature T11 becomes equal to or lower than a predetermined temperature T0. The predetermined temperature T0 is a temperature at which the gas detection element 23 is assumed not to be thermally deteriorated. The predetermined temperature T0 depends on the specification, position, etc. of the gas detection element 23, is determined by a preliminary test or the like, and is stored in the ECU 90.

≪Operation of gas sensor system≫
Next, the operation of the gas sensor system 2 will be described with reference mainly to FIG.
In step S201, which proceeds to the case where the IG 81 is turned off (S101: Yes), the ECU 90 opens the on-off valve 62 and operates the compressor 61 while the butterfly valve 51 is open. Then, scavenging gas is sent into the second gas detection chamber 41 and the like, scavenging of the second gas detection chamber 41 and the like is started, and the temperature T11 of the second gas detection chamber 41 and the like starts to decrease due to the scavenging gas.

  In step S202, the ECU 90 determines whether or not the current temperature T11 is equal to or lower than a predetermined temperature T0. When it is determined that the temperature T11 is equal to or lower than the predetermined temperature T0 (S202 / Yes), the processing of the ECU 90 proceeds to step S203. On the other hand, if it is determined that the temperature T11 is not equal to or lower than the predetermined temperature T0 (No in S202), the determination in step S202 is repeated. In this case, the compressor 61 continues to operate and scavenging is continued.

In step S203, the ECU 90 stops the compressor 61.
Next, in step S106, the ECU 90 closes the butterfly valve 51 and the on-off valve 62 and closes the second gas detection chamber 41 and the like in the same manner as in the first embodiment.

≪Effect of gas sensor system≫
According to such a gas sensor system 2, it is possible to reduce the temperature T11 while reducing the humidity of the second gas detection chamber 41 and the like by the scavenging gas. That is, scavenging can be continued until the temperature T11 of the second gas detection chamber 41 or the like decreases to a predetermined temperature T0 or lower.
As a result, the second gas detection chamber 41 and the like are prevented from being sealed at a high temperature, and thus thermal deterioration of the gas detection element 23 can be prevented.

<< Third Embodiment >>
Next, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7 and different parts from the first and second embodiments.

≪Operation of gas sensor system≫
In step S301, which proceeds to the case where the IG 81 is turned off (S101, Yes), the ECU 90 detects the current hydrogen concentration C11 in the first gas detection chamber 32 via the gas detection element 23.

  In step S302, the ECU 90 (scavenging gas amount determining means) calculates the total amount of scavenging gas to be sent to the second gas detection chamber 41 and the like based on the hydrogen concentration C11 detected in step S301 and the map shown in FIG. And decide. The map shown in FIG. 7 has a tendency that when the hydrogen concentration C11 increases, the scavenging gas amount tends to increase. By scavenging with the calculated scavenging gas amount, the hydrogen concentration C11 decreases and the high concentration C11 increases. It is set so that the gas detection element 23 is not deteriorated by hydrogen. This map is obtained by a preliminary test or the like and stored in the ECU 90.

  In step S303, the ECU 90 determines the operating time of the compressor 61 based on the total amount of scavenging gas calculated in step 302. In addition, since the case where the compressor 61 is operated at a constant rotational speed is illustrated, the operation time of the compressor 61 becomes longer as the hydrogen concentration C11 is higher and the total amount of scavenging gas is larger (see FIG. 7).

In step S304, the ECU 90 opens the butterfly valve 51 and the on-off valve 62, and operates the compressor 61 with the operation time determined in step S303. Thereby, scavenging gas is sent into the 2nd gas detection chamber 41 grade, scavenging is implemented, and humidity H11, temperature T11, and hydrogen concentration C11 of the 1st gas detection chamber 32 and the 2nd gas detection chamber 41 grade fall.
Then, after the operation time has elapsed, the ECU 90 stops the compressor 61 and then closes the butterfly valve 51 and the on-off valve 62 to seal the second gas detection chamber 41 and the like.

≪Effect of gas sensor system≫
According to such a gas sensor system, the scavenging gas can reduce the hydrogen concentration C11 while reducing the humidity H11 and the temperature T11 of the second gas detection chamber 41 and the like. Accordingly, high concentration hydrogen is prevented from being enclosed in the first gas detection chamber 32 and the second gas detection chamber 41, and deterioration (corrosion) of the gas detection element 23 due to high concentration hydrogen can be prevented. .
Further, since the total amount of scavenging gas and the operation time of the compressor 61 are appropriately determined based on the hydrogen concentration C11 when the IG 81 is OFF, the hydrogen concentration C11 can be appropriately reduced.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and the following modifications can be made without departing from the spirit of the present invention.
In the above-described embodiment, the case where the gas to be detected is hydrogen has been exemplified. However, the present invention is not limited to this, and other types of gases may be used. Moreover, although the case where the gas sensor system 1 was mounted in the fuel cell vehicle was described, the structure mounted in the other vehicle may be sufficient.

  In the above-described embodiment, the case where it is determined that the fuel cell automobile (vehicle) is stopped when the IG 81 is turned off is illustrated. However, for example, the fuel cell actually generates power after the IG 81 is turned off. In the configuration of stopping, it may be configured to determine that the fuel cell vehicle has stopped when the power generation of the fuel cell stops.

  In the third embodiment described above, the case where the amount of scavenging gas is determined based on the hydrogen concentration C11 detected through the gas detection element 23 is exemplified. However, the hydrogen concentration is detected separately from the gas detection element 23. A configuration may be employed in which a sensor is provided and the scavenging gas amount is determined based on the hydrogen concentration detected by the sensor.

  In the first embodiment, the scavenging gas amount and the operation time of the compressor 61 are determined based on the humidity H11 when the IG 81 is OFF, and based on the hydrogen concentration C11 when the IG 81 is OFF in the third embodiment. In addition, the case where the compressor 61 is operated and scavenged is illustrated, but in addition, for example, as in the second embodiment, scavenging is started when the IG 81 is turned off, and the humidity H11 is lowered to a predetermined humidity H0 or lower. The scavenging may be continued until the hydrogen concentration C11 falls below the predetermined hydrogen concentration C0. The predetermined humidity H0 is a humidity at which the gas detection element 23 is not deteriorated by moisture, and the predetermined hydrogen concentration C0 is a hydrogen concentration at which the gas detection element 23 is not deteriorated by hydrogen.

  On the contrary, in the second embodiment, the case where the scavenging is continued until the temperature T11 falls below the predetermined temperature T0 is exemplified, but other than this, for example, based on the temperature T11 when the IG 81 is OFF, the scavenging gas The amount and the operation time of the compressor 61 may be determined, and the compressor 61 may be operated and scavenged according to the determined amount.

It is a figure which shows the structure of the gas sensor system which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the gas sensor system which concerns on 1st Embodiment. It is a map which shows the relationship between the humidity which concerns on 1st Embodiment, and the quantity of scavenging gas (operating time of a compressor). It is a figure which shows the structure of the gas sensor system which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the gas sensor system which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the gas sensor system which concerns on 3rd Embodiment. It is a map which shows the relationship between the hydrogen concentration which concerns on 3rd Embodiment, and the quantity of scavenging gas (operation time of a compressor).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas sensor system 20 Hydrogen sensor 23 Gas detection element 30 Element accommodating part 32 1st gas detection chamber 41 2nd gas detection chamber 51 Butterfly valve (valve mechanism)
60 scavenging means 61 compressor 71 humidity sensor 72 temperature sensor 90 ECU (valve mechanism control means, stop determination means, scavenging gas amount determination means)

Claims (5)

A gas sensor system that is mounted on a vehicle, operates corresponding to the vehicle, and detects a gas to be detected.
A gas detection element for detecting the gas to be detected;
A gas detection chamber in which the gas detection element is disposed and a gas to be detected is taken in, and
A valve mechanism capable of maintaining the gas detection chamber in a sealed state;
Valve mechanism control means for controlling the valve mechanism;
Stop determination means for determining whether or not the vehicle has stopped;
With
The gas sensor system, wherein the valve mechanism control unit seals the gas detection chamber by the valve mechanism when the stop determination unit determines that the vehicle has stopped. Scavenging gas is introduced into the gas detection chamber, and scavenging means for scavenging the gas detection chamber is provided,
When it is determined by the stop determination means that the vehicle has stopped, after the gas detection chamber is scavenged by the scavenging means, the valve mechanism control means seals the gas detection chamber by the valve mechanism. The gas sensor system according to claim 1. A humidity sensor for detecting the humidity of the gas detection chamber;
A scavenging gas amount determining means for determining the amount of the scavenging gas based on the humidity of the gas detection chamber;
With
The gas sensor system according to claim 2, wherein the amount of the scavenging gas increases as the humidity of the gas detection chamber increases. A temperature sensor for detecting the temperature of the gas detection chamber;
The gas scavenging system according to claim 2, wherein the scavenging means continues scavenging until the temperature of the gas detection chamber becomes equal to or lower than a predetermined temperature. A scavenging gas amount determining means for determining the amount of the scavenging gas based on the concentration of the gas to be detected in the gas detection chamber;
The gas sensor system according to claim 2, wherein the amount of the scavenging gas increases as the concentration of the detection gas increases.

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