JP5186188B2 - Control device for gas sensor with built-in heater - Google Patents

Description

  The present invention relates to a control device for a gas sensor with a built-in heater.

Conventionally, for example, a hydrogen detector (gas sensor) has been provided in the discharge system on the oxygen electrode side of a fuel cell such as a solid polymer membrane fuel cell, and hydrogen on the fuel electrode side passes through the solid polymer electrolyte membrane by this hydrogen detector. A control device that detects whether or not there is leakage to the pole side is known (for example, see Patent Document 1).
In a fuel cell such as a solid polymer membrane fuel cell as described above, in order to maintain the ionic conductivity of the solid polymer electrolyte membrane, the reaction gas (for example, hydrogen or air) supplied to the fuel cell is humidified. Since water (humidified water) is mixed by the device and the like, and the reaction product water is generated by the electrochemical reaction when the fuel cell is operated, the off-gas of the fuel cell, especially the off-gas on the oxygen electrode side is a highly humid gas. It has become.
For this reason, in the apparatus according to an example of the above-described prior art, condensation may occur in a gas sensor or the like disposed in the off-gas flow path due to the highly humid off-gas discharged from the fuel cell. The gas sensor may be deteriorated or damaged. In particular, since the solid polymer membrane fuel cell described above has a normal operating temperature lower than the vaporization temperature of water, and the offgas is discharged as a gas with a high humidity and a large amount of water, the water in the offgas is discharged. There is a problem of easy condensation.

For such a problem, in the control device according to an example of the above-described prior art, the temperature at a position upstream of the gas sensor in the flow direction in the piping through which the gas to be detected flows, and the gas detection chamber of the gas sensor By controlling the energization amount of the heater that heats the gas detection chamber so that the temperature difference from the temperature is within a predetermined range, the occurrence of condensation in the gas detection chamber is suppressed.
Japanese Patent No. 3833559

By the way, in the control device according to the above-described prior art, simply controlling the energization amount of the heater according to the temperature difference between the temperature upstream of the gas sensor and the temperature in the gas detection chamber, the heater is turned on at an excessive timing. There is a risk that it may start up, resulting in a problem of increased power consumption.
In such a control device, it is possible to prevent excessive power consumption at the heater and to prevent the device configuration from becoming complicated or enlarged in order to eliminate condensation or suppress the occurrence of condensation, for example. Is desired.

  The present invention has been made in view of the above circumstances, and prevents excessive energy consumption and prevents the gas sensor from being damaged, deteriorated, and reduced in detection accuracy while preventing the apparatus configuration from becoming complicated and large. An object of the present invention is to provide a control device for a gas sensor with a built-in heater.

In order to solve the above-described problems and achieve the object, the control device for a heater built-in gas sensor according to the first aspect of the present invention is supplied with fuel gas and oxidant gas to generate power, and based on an output command value. The off-gas provided in the fuel cell in which the output current fluctuates, the pipe through which the off-gas discharged from the fuel cell flows, and the pipe through which the off-gas flows (for example, the outlet side pipe 14 in the embodiment). A gas sensor (for example, the gas sensor 15 in the embodiment) having a heater (for example, the heater 36 in the embodiment) for heating the inside of the gas detection chamber (for example, the gas detection chamber 26 in the embodiment) into which gas can flow. A humidity sensor provided upstream of the gas sensor in the flow direction of the off gas (for example, the upstream state sensor 41 in the embodiment also serves), and the humidity sensor And an energization controller (for example, the controller 10 in the embodiment) that is connected to a power source (for example, the power storage device 4 in the embodiment) and controls power supply from the power source to the gas sensor. The heater built-in type gas sensor control device, wherein the energization controller detects whether or not the humidity of the off-gas upstream of the gas sensor detected by the humidity sensor is equal to or higher than a threshold having hysteresis , When the off-gas humidity on the upstream side of the gas sensor is lower than the low-side threshold value , the energization to the heater is stopped, and the off-gas humidity on the upstream side of the gas sensor is equal to the threshold value . If the threshold is higher than the high side threshold , the heater is energized.

According to the control apparatus of the built-in heater gas sensor according to the first embodiment, the heater on and off the detection value of the humidity sensor, ie a benzalkonium be controlled according to the humidity of the gas to be detected on the upstream side of the gas sensor The heater can be started efficiently, the increase in power consumption can be suppressed, and the gas to be detected that flows into the gas detection chamber even if the gas to be detected is in a saturated water-containing state upstream of the gas sensor As the temperature rises, the saturated water vapor pressure increases, the relative humidity of the gas to be detected can be reduced, and condensation can be prevented from occurring due to the gas to be detected flowing into the gas detection chamber.

Embodiments of a control device for a heater built-in gas sensor according to the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, for example, the control device 1 for a heater built-in gas sensor according to this embodiment includes, for example, a fuel cell 2, a current controller 3, a power storage device 4, a load 5, and an S / C output controller. 6, a supercharger (S / C) 7, a fuel supply device 8, an output current sensor 9, and a controller 10, each fuel cell system 1 a is connected to the fuel cell 2. Among the pipes 11, 12, 13, and 14, the operation start, operation stop, and operation of the heater built-in gas sensor (gas sensor) 15 provided in the oxygen-side outlet pipe 14 are controlled.

The fuel cell 2 is mounted on a vehicle as a power source of a fuel cell vehicle or an electric vehicle, for example, and an electrolyte electrode structure in which a solid polymer electrolyte membrane is sandwiched between a hydrogen electrode and an oxygen electrode is further sandwiched between a pair of separators. A plurality of unillustrated fuel battery cells are stacked.
The inlet side pipe 11 connected to the hydrogen electrode of the fuel cell 2 is supplied with a fuel gas containing hydrogen gas from a fuel supply device 8 having a high-pressure hydrogen tank or the like, for example, and undergoes a catalytic reaction on the catalyst electrode of the hydrogen electrode. The ionized hydrogen moves to the oxygen electrode through a moderately humidified solid polymer electrolyte membrane, and electrons generated by this movement are taken out to an external circuit and used as DC electric energy. . For example, an oxidant gas such as oxygen or air is supplied from a supercharger (S / C) 7 to the inlet side pipe 12 connected to the oxygen electrode, and hydrogen ions, electrons, and oxygen react at the oxygen electrode. As a result, water is generated. Then, the so-called off-gas that has been reacted is discharged out of the system from the outlet side pipes 13 and 14 on both the hydrogen electrode side and the oxygen electrode side. In particular, a solid polymer electrolyte fuel cell normally has an operating temperature lower than the vaporization temperature of water, and the off-gas is discharged as a gas with a high humidity and a large amount of moisture.

  Here, a gas contact combustion type heater built-in gas sensor (gas sensor) 15 is attached to the oxygen electrode side outlet side pipe 14 on the upper side in the vertical direction, and the gas sensor 15 supplies hydrogen from the outlet side pipe 14 on the oxygen electrode side. It can be confirmed that the gas is not discharged.

The supercharger 7 takes in air from the outside of the vehicle, for example, compresses it, and supplies this air as a reaction gas to the oxygen electrode of the fuel cell 2.
The rotational speed of a motor (not shown) for driving the supercharger 7 is based on a control command input from the controller 10, for example, an S / C output controller 6 having a PWM inverter by pulse width modulation (PWM). Is controlled by.

The generated current (output current) taken out from the fuel cell 2 is input to the current controller 3, and a plurality of capacitor cells, such as electric double layer capacitors and electrolytic capacitors, are connected to each other in series. A power storage device 4 made of a connected capacitor or the like is connected.
The fuel cell 2, the current controller 3, and the power storage device 4 are, for example, a traveling motor (not shown), a cooling device (not shown), an air conditioner (not shown), or the like of the fuel cell 2 or the power storage device 4, for example. It is connected in parallel to a load 5 composed of various auxiliary machines and an S / C output controller 6.

In this fuel cell system 1 a, the controller 10 includes, for example, the operating state of the vehicle, the concentration of hydrogen contained in the fuel gas supplied to the hydrogen electrode of the fuel cell 2, and the offgas discharged from the hydrogen electrode of the fuel cell 2. Is supplied from the supercharger 7 to the fuel cell 2 based on the concentration of hydrogen contained in the fuel cell 2, the power generation state of the fuel cell 2, for example, the inter-terminal voltage of each of the plurality of fuel cells, the output current extracted from the fuel cell 2, etc. A command value for the flow rate of air and a command value for the flow rate of the fuel gas supplied from the fuel supply device 8 to the fuel cell 2 are output, and the power generation state of the fuel cell 2 is controlled.
Therefore, a detection signal output from the output current sensor 9 that detects the current value of the output current extracted from the fuel cell 2 is input to the controller 10.
Further, the controller 10 controls the current value of the output current extracted from the fuel cell 2 by the current controller 3 based on the power generation command (FC output command value) for the fuel cell 2.

  For example, as shown in FIGS. 2 and 3, the gas sensor 15 includes a case 21 having a rectangular shape that is long along the longitudinal direction of the outlet side pipe 14. The case 21 is made of, for example, polyphenylene sulfide, and includes flange portions 22 at both ends in the longitudinal direction. The flange portion 22 is provided with a collar 23, and a bolt 24 is inserted into the collar 23 so as to be fastened and fixed to the mounting seat 14 a of the outlet side pipe 14.

A cylindrical portion 25 made of ceramic is provided on an end face (for example, a lower surface) in the thickness direction of the case 21 via a base portion 35 described later. The cylindrical portion 25 penetrates the outlet side pipe 14. The hole 14b is inserted from the outside.
The inside of the cylindrical portion 25 is formed as a gas detection chamber 26, and a flange portion 27 made of ceramic is integrally formed on the inner side surface 26 </ b> A of the gas detection chamber 26 toward the inner peripheral side. A portion is formed as an opening as the gas introduction portion 28.
Further, a sealing material 29 is attached to the outer peripheral surface 25A of the cylindrical portion 25 and is in close contact with the inner peripheral wall of the through hole 14b of the outlet side pipe 14 to ensure airtightness.

A circuit board 30 sealed with resin is provided in the case 21. For example, a pair of detection elements 31 and a temperature compensation element 32 disposed in the gas detection chamber 26 are connected to the circuit board 30. A plurality of stays 33 (support members) and lead wires 34 are connected to the circuit board 30.
The energizing stay 33 is formed of, for example, a composite alloy material such as a copper alloy, an iron alloy, or a nickel alloy, and penetrates a substantially annular plate-like base portion 35 disposed between the case 21 and the cylindrical portion 25. The base end portion is connected to the circuit board 30 in the case 21 and the tip end portion protrudes into the gas detection chamber 26, and is formed in a flat plate shape from an insulating material such as alumina or glass epoxy. It is fixed by the base part 35.

A flat heater 36 such as a PTC (positive temperature coefficient) thermistor made of barium titanate or the like is provided on the inner side surface 26A of the gas detection chamber 26, for example.
Note that the heater 36 has, for example, a circular plate shape, and is provided with electrical terminals for energization at both ends in the radial direction.
Moreover, by setting the heater 36 to, for example, a PTC thermistor, the Curie temperature can be arbitrarily set by the material composition of the semiconductor ceramic mainly composed of barium titanate constituting the PTC thermistor. The heater 36 can be a constant temperature heating element by utilizing the property that electric resistance increases rapidly.
That is, the PTC thermistor self-heats due to Joule heat when a voltage is applied to the PTC element, and when the temperature of the PTC element exceeds the Curie temperature, the resistance value of the PTC element increases logarithmically. As a result, the current supplied to the PTC element is reduced and the increase in power is suppressed, so that the heat generation temperature is lowered. And if the resistance value of a PTC element falls, since the electric current supplied to a PTC element will increase and electric power will increase again, heat_generation | fever temperature will increase. By repeating this series of operations, the PTC thermistor functions as a constant temperature heating element having a self-control function.

  A state sensor 37 for detecting the temperature and humidity around each element 31, 32 in the gas detection chamber 26 is fixed by the base portion 35, and the state sensor 37 is connected to the circuit board 30 in the case 21.

The gas introduction portion 28 includes a net-like or porous explosion-proof structure 38 (for example, a sintered filter) made of, for example, metal or ceramic, sequentially from the base end portion to the tip end portion along the thickness direction of the gas sensor 15. For example, a water repellent filter 39 made of resin is disposed. The explosion-proof structure 38 is in contact with the heater 36 and is directly heated by the heater 36.
As a result, the inspection target gas is sequentially introduced from the outside through the water-repellent filter 39 and the explosion-proof structure 38 heated directly by the heater 36 into the gas detection chamber 26, and the temperature of the inspection target gas is increased. Is kept at a temperature above the dew point. In addition, it is possible to prevent dew condensation from occurring in the explosion-proof structure 38 that is in contact with the gas to be inspected, and this moisture is evaporated even when moisture adheres to the explosion-proof structure 38.

The detection element 31 is a well-known element, and the surface of the coil of a metal wire containing platinum or the like having a high temperature coefficient with respect to electric resistance is a catalyst made of a noble metal or the like that is active against hydrogen to be detected gas. It is formed in a substantially spherical shape with a carrier such as alumina to be carried.
The temperature compensation element 32 is inactive with respect to the gas to be detected. For example, the surface of the coil equivalent to the detection element 31 is formed in a substantially spherical shape with a carrier such as alumina.
And the detection element 31 which became high temperature by the heat_generation | fever of the combustion reaction produced when the hydrogen gas which is a detection gas contacts the catalyst of the detection element 31, and the combustion reaction by a detection gas does not generate | occur | produce but detection element 31 By utilizing the fact that a difference in electrical resistance value occurs between the temperature compensation element 32 and the low temperature compensation element 32, it is possible to detect the hydrogen concentration by offsetting the change in the electrical resistance value due to the ambient temperature.

The detection element 31 and the temperature compensation element 32 are connected to the circuit board 30 and, for example, a pair is provided in the gas detection chamber 26 at the same height in the vertical direction with a predetermined interval.
For example, as shown in FIG. 2, the gas detection chamber 26 stands between the detection element 31 and the temperature compensation element 32 along the inflow direction of the detection gas so as to block both elements 31 and 32. In this state, a plate-shaped heat shield member 40 is arranged. The heat shut-off member 40 prevents heat transfer due to radiation caused by mutual heat generation between the detection element 31 and the temperature compensation element 32, and detects the gas to be detected flowing into the gas detection chamber 26. The elements 31 and the temperature compensation elements 32 are distributed equally so as to be distributed.

For example, as shown in FIG. 4, in the outlet pipe 14 on the oxygen electrode side to which the gas sensor 15 is attached, the temperature of the gas to be detected at the upstream position adjacent to the attachment site of the gas sensor 15 in the flow direction of the gas to be inspected. An upstream state sensor 41 for detecting the humidity, that is, the gas temperature and gas humidity on the upstream side of the gas sensor 15 is attached.
The upstream side state sensor 41 is configured such that a base 42 is inserted and fixed in a through hole 14 c formed in the outlet side pipe 14, and a tip detection part 43 is inserted into the outlet side pipe 14. Note that a sealing material 44 is attached to the outer peripheral wall of the base portion 42 of the upstream side state sensor 41 to ensure a sealing property between the upstream side state sensor 41 and the through hole 14c.

The controller 10 is connected to an upstream state sensor 41 attached to the outlet side pipe 14 and a state sensor 37 provided inside the gas sensor 15, and is connected to a heater 36 of the gas sensor 15.
The controller 10 then activates the gas sensor 15 and the heater 36 according to, for example, the operating state of the fuel cell 2, for example, starts operation (that is, starts energizing the heater 36) and stops operation (that is, the heater 36). For example, from the power storage device 4 to the detection element 31, the temperature compensation element 32, and the heater 36.

For example, the controller 10 controls the start and stop of energization of the heater 36 in accordance with the gas humidity upstream of the gas sensor 15 output from the upstream state sensor 41, and at the time of energization of the heater 36. The energization amount to the heater 36 is controlled based on the temperature detected by the state sensor 37 and the upstream side state sensor 41.
For example, in the controller 10, the humidity (detected humidity value) of the gas to be detected upstream of the gas sensor 15 detected by the upstream state sensor 41 is equal to or higher than the threshold humidity HY (L / H) having a predetermined hysteresis. The start and stop of energization to the heater 36 are controlled according to the determination result. Further, for example, when the heater 36 is energized during the operation of the fuel cell 2 or the like, the temperature in the gas detection chamber 26 (detected chamber temperature) detected by the state sensor 37 and the gas sensor detected by the upstream state sensor 41 Based on the temperature of the gas to be detected upstream of 15 (upstream gas temperature), the detection chamber temperature is set to be higher than the upstream gas temperature by a predetermined temperature (for example, a predetermined temperature of 0 ° C. or more and 5 ° C. or less). Thus, the energization amount of the heater 36 is controlled. At this time, the controller 10 controls the heater by, for example, feedback control with respect to a current value supplied to the heater 36, chopper control based on, for example, on / off operation of the switching element (that is, on / off switching control). 36 is controlled.

  The heater built-in gas sensor control device 1 according to this embodiment has the above-described configuration. Next, the operation of the heater built-in gas sensor control device 1, in particular, the start and stop of energization of the heater 36, the heater An operation for controlling the energization amount when energization to 36 will be described.

First, for example, in step S01 shown in FIG. 5, the humidity (detected humidity value) of the gas to be detected upstream of the gas sensor 15 detected by the upstream state sensor 41 has a threshold humidity HY (L / H) It is determined whether or not.
If the determination result is “NO”, that is, if the humidity detection value is less than the predetermined low-side threshold humidity HY (L), the process proceeds to step S10 described later.
On the other hand, if this determination is “YES”, that is, if the humidity detection value is greater than or equal to the predetermined high-side threshold humidity HY (H), the process proceeds to step S02.

In step S02, it is determined whether the energization of the heater 36 is stopped.
If this determination is “NO”, the flow proceeds to step S 04 described later.
On the other hand, if the determination is “YES”, the flow proceeds to step S03.

In step S03, energization of the heater 36 is started.
In step S04, the temperature of the gas to be detected upstream from the gas sensor 15 detected by the upstream state sensor 41 from the temperature in the gas detection chamber 26 detected by the state sensor 37 (detection chamber temperature) ( A value obtained by subtracting (upstream gas temperature) is set as a temperature difference detection value.
In step S05, the temperature difference detection value is a high threshold temperature difference TE (H) (for example, an appropriate value of 0 ° C. or more and 5 ° C. or less) of the threshold temperature difference TE (L / H) having a predetermined hysteresis. Whether it is greater than 5 ° C. or the like.
If this determination is “NO”, the flow proceeds to step S 07 described later.
On the other hand, if this determination is “YES”, the flow proceeds to step S 06.
In step S06, the energization current to the heater 36 is reduced, and the series of processes is terminated. Thereby, the temperature difference detection value is decreased by lowering the detection room temperature to secure a desired temperature difference, and excessive power consumption is prevented.

In step S07, the threshold temperature difference TE (L / H) having a predetermined hysteresis as the temperature difference detection value is a low-side threshold temperature difference TE (L) (for example, an appropriate value between 0 ° C. and 5 ° C.). And whether it is smaller than 0 ° C. or the like.
If this determination is “NO”, the flow proceeds to step S 09 described later.
If this determination is “YES”, the flow proceeds to step S08.
In step S08, the energization current to the heater 36 is increased, and the series of processes is terminated. Thereby, the temperature difference detection value is increased by raising the detection room temperature to secure a desired temperature difference, and the prevention of the occurrence of condensation in the gas sensor 15 is made more reliable.
In step S09, the energization current to the heater 36 at this time is maintained, and a series of processing ends.

In step S10, it is determined whether or not the energization of the heater 36 is stopped.
If the determination result is “YES”, the series of processes is terminated.
On the other hand, if this determination is “NO”, the flow proceeds to step S11.
In step S11, the energization to the heater 36 is stopped, and a series of processing ends.

As described above, according to the heater built-in gas sensor control apparatus 1 according to the present embodiment, excessive energy consumption in the heater 36 is prevented and, for example, a dedicated gas for drying the gas detection chamber 26 is used. By providing the supply device, it is possible to prevent the gas sensor 15 from being damaged, deteriorated, and lowered in detection accuracy due to condensation while preventing the device configuration from becoming complicated and large.
That is, since the heater 36 in the gas detection chamber 26 is turned on and off according to the humidity of the gas to be detected upstream of the gas sensor 15, the heater 36 is unnecessarily activated at an excessive frequency. And the inside of the gas detection chamber 26 can be appropriately dried.
When the heater 36 is on, the temperature of the heater 36 is controlled so that the temperature in the gas detection chamber 26 is higher than the temperature of the gas to be detected upstream of the gas sensor 15 by a predetermined temperature or more. Therefore, it is possible to prevent the dew condensation from newly occurring due to the gas to be detected flowing into the gas detection chamber 26.

Further, of the oxygen gas side off gas discharged from the fuel cell 2 and flowing in the outlet side pipe 14, the off gas reaching the gas detection chamber 26 of the gas sensor 15 has a temperature difference in a predetermined range from the upstream side off gas. Thus, since the heater 36 heats, the relative humidity is reduced as compared with the upstream off-gas.
As a result, the inside of the gas detection chamber 26 has a temperature difference with a margin with respect to the dew point, and it is possible to prevent moisture in the off-gas from condensing in the gas detection chamber 26. In this case, it is possible to prevent condensed water from coming into contact with the detection element 31 and damaging or deteriorating the detection element 31, thereby enhancing the durability of the detection element 31 and increasing the detection accuracy.

  Further, the off-gas in the gas detection chamber 26 that has become higher than the upstream gas temperature by being heated by the heater 36 causes a temperature difference (temperature difference detection value) from the upstream gas temperature to have a predetermined hysteresis by the controller 10. For example, the temperature difference detection value is too small (temperature difference detection value <low-side threshold temperature difference TE (L)), because the threshold temperature difference TE (L / H) is set within a predetermined range. Condensation occurs in the gas sensor 15 or the temperature difference detection value becomes larger than necessary (temperature difference detection value ≧ high-side threshold temperature difference TE (H)), and wasteful power consumption is prevented from being minimized. Generation of condensation in the gas sensor 15 can be prevented with energy.

  In the above-described embodiment, the flat heater 36 is a PTC thermistor, but is not limited to this. Other heaters such as a heater made of a linear material having a large electric resistance may be used. For example, a part of an electric circuit formed by printing and firing a conductive resistor on the surface of the base portion 35 may be used. The heater which makes the conductor pattern of may be sufficient.

  In the above-described embodiment, the gas sensor 15 is a contact combustion type sensor. However, the gas sensor 15 is not limited to this. For example, according to the element resistance value generated when the gas to be detected comes out of contact with oxygen on the surface of the detection element. It may be a gas sensor based on another method such as a semiconductor type for detecting the gas concentration, or a gas sensor composed of both a contact combustion type and a semiconductor type sensor.

The control function executed by the controller 10 may be executed by a microcomputer or IC (not shown) mounted on the circuit board 30.
Further, the variation in detection sensitivity of the gas sensor 15 may be corrected based on the temperature and relative humidity in the gas detection chamber 26 detected by the state sensor 37.

  In the embodiment described above, the explosion-proof structure 38 and the water repellent filter 39 are arranged in the gas introduction portion 28 sequentially from the base end portion to the tip end portion along the thickness direction of the gas sensor 15. However, the present invention is not limited to this. For example, the water repellent filter 39 and the explosion-proof structure 38 may be sequentially arranged from the base end portion to the tip end portion.

1 is a configuration diagram of a fuel cell system including a heater built-in gas sensor control device according to an embodiment of the present invention. FIG. It is a top view of the gas sensor which concerns on one Embodiment of this invention. It is a schematic sectional drawing which follows the AA line shown in FIG. It is a block diagram of the control apparatus of the gas sensor with a built-in heater which concerns on one Embodiment of this invention. It is a flowchart which shows the operation | movement of the control apparatus of the gas sensor with a built-in heater which concerns on one Embodiment of this invention, especially the operation | movement which controls the start and stop of electricity supply to a heater, and the energization amount at the time of energization to a heater. .

Explanation of symbols

1 Heater built-in gas sensor control device 1a Fuel cell system 4 Power storage device (power supply)
10 Controller (energization controller)
14 Outlet piping (piping)
15 Gas sensor 26 Gas detection chamber 36 Heater 37 Condition sensor (first temperature sensor)
41 Upstream state sensor (second temperature sensor, humidity sensor)

Claims (1)

A fuel cell in which fuel gas and oxidant gas are supplied to generate power, and an output current varies based on an output command value; and
Piping through which off-gas discharged from the fuel cell circulates;
A gas sensor provided in the pipe through which the off gas flows, and having a heater for heating the gas detection chamber into which the off gas can flow;
A humidity sensor provided upstream of the gas sensor in the flow direction of the off gas;
A heater built-in type gas sensor control device comprising: the humidity sensor; and a power supply controller connected to a power source and controlling power supply from the power source to the gas sensor,
The energization controller is
Detecting whether the humidity of the off-gas upstream of the gas sensor detected by the humidity sensor is equal to or higher than a threshold having hysteresis ;
When the humidity of the off gas on the upstream side of the gas sensor is less than the low threshold value of the threshold value , the energization to the heater is stopped,
The heater-incorporated gas sensor control apparatus, wherein the heater is energized when the humidity of the off-gas upstream of the gas sensor is equal to or higher than the high threshold value .

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