JPH0531738B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a temperature control device for an oxygen sensor, and more particularly to a temperature control device for maintaining the activation temperature of an oxygen sensor that detects the oxygen concentration in the exhaust gas of an internal combustion engine. .

[Prior art]

Conventionally, magnetic type,
Oxygen concentration detectors such as density type and thermal conduction type are used. Among these, current-limiting oxygen concentration detectors using solid electrolytes such as zirconia are attracting attention as sensors for precise combustion control in internal combustion engines due to their linear output characteristics.

Incidentally, it is important that the oxygen concentration be detected by the oxygen concentration detector in a region where the detector output is stable and at a substantially constant temperature. For example, in internal combustion engines for automobiles, the exhaust temperature of the internal combustion engine is controlled, or when the exhaust temperature is low, the oxygen concentration detector is activated by a heater (Japanese Patent Laid-Open No. 57-48648), and the heater also serves as a temperature sensor. A device was installed inside the oxygen concentration detector to control the amount of heat generated by the heater so that the temperature remained almost constant (Japanese Patent Laid-Open No.
57-192852).

However, among the above-mentioned conventional techniques, the method of controlling the exhaust gas temperature greatly restricts the operation of the internal combustion engine, and the method of simply heating the heater when the exhaust temperature is low is useful for quickly raising the temperature of the oxygen concentration detector. is difficult to maintain at a constant temperature. Furthermore, if the oxygen concentration detector is equipped with a temperature detection device, the structure of the sensor itself will be complicated, making it difficult to mass produce and increasing the possibility of failure. There was also a situation where the oxygen concentration detection part was still at a low temperature even after the oxygen concentration was detected, and there was a possibility that precise control of the internal combustion engine would be hindered.

One solution to this problem is to maintain the temperature of the oxygen sensor in an active state regardless of the state of the internal combustion engine by providing the oxygen sensor with an amount of heat that corresponds to the operating state of the internal combustion engine. [Problems to be Solved by the Invention] However, if there is a fluctuation in the power supply voltage or a change in the resistance value of the heat generating means over time, the desired amount of heat generation may not be obtained. Therefore, even though the power supply is actually becoming insufficient, power is supplied based on the voltage or resistance value set from the beginning, resulting in less power than necessary, and the oxygen sensor is not fully functioning. This means that the amount of oxygen will be detected without activation. This causes the oxygen sensor to give an inaccurate output.

SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature control device for an oxygen sensor that does not complicate the structure of the oxygen sensor, ensures activation of the oxygen sensor, and provides accurate output.

[Means to solve the problem]

As illustrated in FIG. 1, the temperature control device for an oxygen sensor of the present invention includes: an operating state detection means for detecting the operating state of an internal combustion engine; and an oxygen sensor for detecting the oxygen concentration in the exhaust gas of the internal combustion engine. a heat generating means; a supply power adjusting means for adjusting the power supplied to the heat generating means in accordance with a command signal; a power detecting means for outputting a signal indicating the power actually supplied to the heat generating means; and the operating state. determining means for determining a state in which the heating means should be heated based on the operating state of the internal combustion engine detected by the detecting means; and a heat generation amount control means that adjusts a command signal to the power supply adjustment means in accordance with the detected power detected by the power detection means so that the required power corresponding to the power is supplied.

[Effect]

The determining means determines the state in which the heat generating means should be heated based on the data obtained from the operating state detecting means. Based on this determination result, the calorific value control means supplies the necessary power corresponding to the target temperature of the oxygen sensor to the heat generating means. In order to perform this supply appropriately, the calorific value control means adjusts a command signal to the power supply adjustment means in accordance with the detected power detected by the power detection means. Due to this,
Activation of the oxygen sensor is done properly.

For example, if there is a fluctuation in power due to fluctuations in the power supply voltage or changes in the resistance value of the heat generating means over time, the heat generation control means detects the fluctuation based on the output of the power detection means, and further calculates the amount of power supplied based on the fluctuation. The regulating means regulates the electric power supplied to the heat generating means. As a result, even if there is a fluctuation in the power supply voltage or a change in the resistance value of the heat generating means over time, the oxygen sensor can always be activated and the oxygen concentration state can be accurately determined.

In this way, in order to maintain the activated state of the oxygen sensor, a temperature detection device is not used, but instead a power detection means is used for the oxygen sensor. It is only necessary to provide the detection means separately from the oxygen sensor. Therefore, it is possible to ensure activation of the oxygen sensor and obtain accurate output without complicating the structure of the oxygen sensor.

Next, embodiments of the present invention will be described with reference to the drawings.

〔Example〕

FIG. 2 shows an electronic fuel injection system for an automobile engine and an air-fuel ratio control system incorporated therein. That is, 1 is a cylinder of the engine 2, 3 is an exhaust manifold connected to the exhaust port 5 of each cylinder of the cylinder head 4, 6 is an intake manifold connected to the intake port 7 of the cylinder head 4, and the intake manifold 6 is connected to the exhaust port 5 of each cylinder. is connected to the surge tank 8. An air flow meter 9 that detects the intake air amount from an air cleaner (not shown) is connected to the surge tank 8, and an intake temperature sensor 10 that detects the intake air temperature is installed near the air flow meter 9. Reference numeral 11 denotes an intake air bypass passage that bypasses the throttle valve 12 that controls the amount of intake air sent to each cylinder via the surge tank 8;
Reference numeral 3 indicates a fuel injection valve that controls the amount of fuel to be injected, which is provided near the tip of the intake manifold 6 on the side of the intake port 7. Reference numeral 14 indicates a throttle opening sensor that detects the opening of the throttle valve 12; The valve 13 is driven and controlled by a control circuit 15, and the latter throttle sensor 14 is connected to output a signal to the control circuit 15 in accordance with the throttle opening. 16 is attached to the exhaust manifold 3,
An air-fuel ratio sensor 17 consisting of an oxygen concentration detection section as an oxygen sensor for detecting the oxygen concentration in exhaust gas and a heater section as a heat generating means for heating the detection section.
is a water temperature sensor that detects the cooling water temperature of engine 2,
Reference numeral 18 denotes a distributor that applies a high voltage output from the igniter 19 to each spark plug 18a of the engine 2 at a predetermined timing, and 20 is attached to the distributor 18 and generates a pulse signal corresponding to the rotation speed of the engine 2. The detection signals of the air-fuel ratio sensor 16, the water temperature sensor 17, and the rotation speed sensor 20 are transmitted to the control circuit 1.
5 is output. Among the above configurations, air flow meter 9, intake temperature sensor 10, throttle opening sensor 1
4. The water temperature sensor 17 and the rotation speed sensor 20 correspond to the operating state detection means of the internal combustion engine. Further, the control circuit 15 also functions as a power supply adjustment means, a power detection means, a determination means, and a heat generation amount control means. Control circuit 1
5, the energization control circuit 38, which will be described later, corresponds to the power supply adjustment means, and the power consumption detection circuit 39 corresponds to the power detection means. The determination means and the calorific value control means are realized by a program executed within the microcomputer 37.

The structure of the air-fuel ratio sensor 16 described above is shown in FIG.
Shown in b.

In FIG. 3A, reference numeral 16a is an oxygen concentration detection section, which forms a sheath body having a U-shaped cross section. Electrode layers are provided on the inner and outer surfaces of the oxygen concentration detection section 16a, and by applying a predetermined voltage between the lead wires 31a and 31b electrically connected to the electrode layers, a current flows between the two electrode layers. is measured to detect the oxygen concentration of the exhaust gas flowing through the exhaust manifold 3. Further, a heater 16b is inserted into the sheath of the oxygen concentration detection section 16a, and a lead wire 32
By applying a voltage between a and 32b, heat is generated and the amount of heat is supplied to the oxygen concentration detection section 16a. The oxygen concentration detection section 16a and the heater 16b are combined in an insulated state. Also, hood 16
c covers the oxygen concentration detection section, and is configured such that exhaust gas is supplied to the surface of the oxygen concentration detection section 16a through a through hole 16c1 formed therein by a diffusion phenomenon. This hood 16c protects the oxygen concentration detection section 16a and also protects the exhaust manifold 3.
This is to equalize the concentration of oxygen that diffuses and flows into the hood 16c from the exhaust gas flowing therein.

Oxygen concentration detection section 16 of the air-fuel ratio sensor 16
a, the heater 16b and the hood 16c are fixedly integrated by a mounting base 16d, and are fixed to the exhaust manifold 3.

The hood 16c of the air-fuel ratio sensor 16 described above was a single hood, but as shown in FIG.
e, 16f may be provided. Of course, these structures are also attached to the exhaust manifold 3 using a suitable mounting base 16g.

Next, FIG. 4 shows a block diagram showing the configuration of the above-mentioned control circuit 15. In the figure, 31 is an application power source for applying a predetermined voltage to the oxygen concentration detection section 16a of the air-fuel ratio sensor 16, 32 is a resistor for detecting the current flowing to the detection section 16a, and 33 is a resistor 3.
2 is an amplifier circuit for amplifying the voltage drop at 2 by a predetermined time; 34 is an output signal from the amplifier circuit 33, that is, an analog signal corresponding to the oxygen concentration in the exhaust gas, an air flow meter 9, an intake temperature sensor 10, and a throttle opening degree; This is an A/D converter that receives analog signals detected by the sensor 14, water temperature sensor 17, etc., and converts them into digital signals. Further, 35 represents a drive circuit which is controlled by a control signal calculated and outputted by the microcomputer 37, and drives the fuel injection valve 13.
This circuit outputs a drive signal for supplying the desired amount of fuel calculated in the engine 2 to the engine 2. The igniter 19 is also controlled by the microcomputer 37 so as to output a high voltage to the distributor 18 at a predetermined timing.

38 is an energization control circuit that is similarly controlled by the microcomputer 37 and controls the energization to the heater section 16b of the air-fuel ratio sensor 16, for example, the amount of energization and the energization time. The power consumed by the heater section 16b is detected by the power consumption detection circuit 39, and the power consumed by the heater section 16b is detected by the power consumption detection circuit 39.
(random access memory).

In this embodiment, among the above configurations, an air flow meter 9, an intake air temperature sensor 10, a throttle opening sensor 1
4. Based on the output signals from the water temperature sensor 17 and the rotation speed sensor 20, the control circuit 15 controls the amount of power supplied to the heater section 16b of the air-fuel ratio sensor 16.

FIG. 5 shows a heater section 16 which is the main part of this embodiment.
The energization control circuit 38 of FIG. 4 performs the heat generation control of b.
and the power consumption detection section 39 will be explained in more detail. Here, 51 represents an oxygen concentration detection section;
2 represents a heater section. Reference numeral 53 denotes a switching circuit consisting of a thyristor or a transistor corresponding to the energization control circuit, which supplies a predetermined amount of current to the heater section 52 based on the output from the microcomputer 37 side. The output from the microcomputer 37 is a pulse signal with a duty D as shown in FIG. 6, and the amount of current applied to the heater section 52 is controlled at the rate of the duty D.

Also, 54 is an A/D corresponding to the power consumption detection circuit.
This converter circuit converts the voltage between points P1 and P2 in FIG. 5 into a digital quantity and outputs it to the microcomputer 37. 56 is a voltage detection resistor, and Tm indicates a terminal to which voltage is applied from the power supply.

In such a configuration, when a voltage of value V ₁ is applied to point P1 and a voltage of value V ₂ is applied to point P2, the voltages detected by the A/D converter 54 are V ₁ , V ₂ It is. From this, in order to realize the necessary amount of power W to be supplied to the heater section 52 calculated from the operating state of the internal combustion engine, the resistance during operation of the switching circuit 53 must be
If it is negligible compared to the resistor 56, a pulse signal with a duty D that satisfies the following equation (1) may be output from the microcomputer 37 to the switching circuit 53.

W=(V ₁ -V ₂ )・V ₂ /r・D (%)/100...(1) In the above configuration, if the resistance of the switching circuit 53 cannot be ignored, the point P2 is between the heater section 52 and the resistor 56. You can also use it as

As another example, a constant current circuit 71 may be provided as shown in FIG. 7, and energization to the heater section 52 may be controlled by a switching circuit 72. In this case, the relationship between the power supplied to the heater section 52 and the duty D of the output pulses from the microcomputer 37 to the switching circuit 72 is expressed by the following equation (2), where _i0 is the current flowing under the control of the constant current circuit 71. It becomes like that.

W=(V ₁ - V ₂ )・i ₀・D (%)/100...(2) Also, as another example, as shown in Figure 8, the voltage
₀ , the A/D converter 82 converts the voltage V ₂ after the voltage drop due to the heater section 52 to the point P.
3 may be used. Here, 83 is a switching circuit, and 84 is a voltage detection resistor having a resistance value r. The relationship between W and D in this case is as shown in the following equation.

W=(V ₀ −V ₂ )・V ₂ /r・D (%)/100…(1-1
) Next, in the above-described configuration, the amount of heat generated by the heater section is controlled based on input signals from each operating state detection means. In this case, a flow chart of a program executed by the microcomputer 37 that controls the amount of power supplied to the heater section will be explained.

FIG. 9 is a flowchart showing a first example of the program. Here, 110 represents a step for initializing various variables and flags. 1
20 represents a step for determining whether or not the air-fuel ratio sensor 16 is in an active state. Air fuel ratio sensor 16
is active or not by applying two types of voltages to the solid electrolyte element of the oxygen concentration detection unit 16a, and determining that it is active if the difference in the current flowing at that time is less than a predetermined value, or It is determined whether the sensor is active or not by reversing the positive and negative sides of the voltage and comparing the difference in the current value flowing at that time, or by measuring the oxygen concentration in the exhaust gas during fuel cut. 130 represents a step for controlling the heater section 16b with a preset duty. Reference numeral 140 represents a step for reading various parameters representing the operating state of the internal combustion engine, such as intake air amount, fuel injection amount, cooling water temperature, and engine speed. 150 represents a step for measuring and calculating the exhaust flow rate. Since the exhaust flow rate is parallel to the intake air amount Q ₀ found in step 140 above,
It is found by multiplying Q ₀ by a constant coefficient.
160 represents a step for calculating the expected value T of the exhaust gas temperature from the data obtained in steps 140 and 150 above. This calculation is performed from a map based on the various parameters mentioned above, for example, through experiments. 170 represents a step of determining whether or not the exhaust gas temperature T determined in step 160 is less than T ₀ which is the target temperature of the oxygen concentration detection section 16a. 180 represents a step of calculating the duty of a control signal that determines the amount of power to heat the heater section 16b. In this calculation, the data D is determined by the following method. First, since the amount of heat K flowing out from the oxygen concentration detecting section 16a at the temperature _T0 is proportional to the square of the difference with the ambient temperature T and proportional to the gas flow rate Q, the above K can be expressed as shown in the following equation (3).

K=A・Q・(T−T ₀ ) ² …(3) Here, A is a proportionality constant. Furthermore, by supplying the same amount of heat from the heater 16b as the amount of heat flowing out from the oxygen concentration detection section 16a, the temperature of the oxygen concentration detection section 16a can be set constant at the target temperature _T0 . The amount of heat K ₀ received is proportional to the electric power W given to the heater section 16b, and there is a relationship as shown in the following equation (4).

K ₀ =B・W=K (4) Here, B is a proportionality constant.

From the above equations (3) and (4), the electric power W supplied to the heater section 16b is expressed as the following equation (5).

W=A/B・Q・(T−T ₀ ) ² …( ₅ ) Here, if we use the circuit shown in _FIG .・
Since the relationship V ₂ /r・D/100=A/B・Q・(T−T ₀ ) ² holds, D=A/B・Q・(T−T ₀ ) ² /(V ₁ −V ₂ )・V ₂ /r
・100…(6) Furthermore, among the variables used in the calculations of equations (1), (2), and (1-1), the values of V ₁ and V ₂ are as described above,
The output values of the A/D converters 54 and 82 are read and used. If the switching circuit 53 is controlled using the calculation result of this duty D, the oxygen concentration detection section 51 will be maintained at a predetermined temperature _T0 .

Next, 190 represents a switch that sets the duty to 0. This is because since the atmospheric temperature T is equal to or higher than the target temperature T ₀ , it is no longer necessary to energize the heater section 16b. 200 is step 18 above
This represents a step in which the heater section 16b is controlled by the duty D determined at 0.190.

When the program as described above is started, initial settings are first made in step 110, and then it is determined in step 120 whether or not the air-fuel ratio sensor 16 is active. If it is not active, step 130 is executed and the preset settings are performed. Heater 1 at duty D
6b. This is because, since the air-fuel ratio sensor 16 is still in a cooled state, the heater 16b is controlled at the duty D set for raising the temperature, and the temperature of the oxygen concentration detection section 16a is quickly raised. On the other hand, if the sensor 16 is activated and the determination is ``YES'' in step 120, various parameters are read in step 140, and then the exhaust flow rate is calculated in step 150.
Next, in step 160, the exhaust temperature is determined.
Next, in step 170, the exhaust temperature T is set to the target temperature.
It is determined whether T is less than ₀ or not. If T<T ₀ here, step 18 is performed to maintain the oxygen concentration detection section 16a at T ₀ so that the temperature does not drop below the activation temperature.
A duty calculation of 0 is performed, and on the other hand, if T≧T ₀ , it is determined as “NO” and there is no longer a need for heating, so the duty is set to 0 in step 190.
is set to Next, in step 200, the heater is controlled at duty D, and step 1 is started again.
Return to 20.

Among the above processes, the processes in steps 160 and 170 correspond to the process as a determination means, and the processes in step 18
The processing of 0.200 corresponds to the processing as a heat generation amount control means.

With this embodiment, the temperature of the oxygen concentration detecting section 16a can be maintained constant at or above the activation temperature even without having a temperature detecting section in the air-fuel ratio sensor 16. It is something. Therefore, the air-fuel ratio sensor 16 does not need to have a complicated structure, but instead has a simple structure, the manufacturing yield is high, there are few failures, and the number of parts is small, which contributes to resource saving.

Furthermore, even if there is a fluctuation in the power supply voltage or a change in the resistance value of the heater section 16b over time, the power consumption detection circuit 3
The fluctuation change is detected at 9, and the energization control circuit 3
8 to the heater section 16b, the oxygen concentration detection section 16a can be activated at all times, and the oxygen concentration state can be accurately known.

In this way, the power consumption detection circuit 39 that detects the power to the heater section 16b is used to maintain the activated state of the oxygen concentration detection section 16a without using a temperature detection device. 16a
It is sufficient to simply provide a simple power consumption detection circuit 39 in the control circuit 15, which is a location other than the air-fuel ratio sensor 16, without providing a temperature detection device for the air-fuel ratio sensor 16.
Therefore, the structure of the air-fuel ratio sensor 16 is not complicated, and the activation of the oxygen concentration detecting section 16a is ensured, so that accurate output can be obtained.

Next, a flowchart as a second example of the control program is shown in FIG. It is assumed that the configuration shown in FIG. 5 is used as the temperature control device.

Here, 210 represents a step for initializing various variables and flags. 220 represents a step for determining whether the operating condition is a medium load steady state. This medium load steady state is when the engine speed is within a certain range of values, for example 1500 to 3000 rpm,
and the fluctuation rate is small and within the range of intake air amount,
For example, it refers to an operating condition in which the fluctuation is small, about 1/10 to 1/8 of the full load. If the operating state is not a steady state and is determined to be "NO", the processing in this routine ends. On the other hand, if the operating state has reached a steady medium load state, step 220
If the result is ``YES'', the process moves to step 230, where power is started to be applied to the switching circuit 53, which is a heater drive circuit made up of, for example, a transistor, and the value of the timer counter at that time is stored in the RAM of the microcomputer 37. Store. Next, in step 240, the values of V ₁ and V ₂ are read,
Next, in step 250, the total power W expected to be required in a temperature atmosphere where the exhaust temperature has reached in a medium load steady state is calculated in advance (this may be a map of W using the rotational speed and intake air amount as parameters). Duty D is calculated from V ₁ and V ₂ taken in step 240 above. Next, in step 260, the setting cycle at which the switching circuit 53 should be energized is determined.
The energization time T ₁ is calculated from T ₂ and the duty D determined in step 250 above. This calculation is given by T ₁ =T ₂ ×D/100. This setting cycle
T ₂ is defined as such that when energization and de-energization are performed at this period, the pulsation of temperature changes in the heater section 52 and the oxygen concentration detection section 51 can be ignored. . Next, in step 270, the energization start time T ₀ and the energization time are determined.
The energization stop time T ₀ +T ₁ is calculated from T ₁ , and in the next step 280, when the timer counter and T ₀ +T ₁ match, the energization to the switching circuit 53 is stopped. Next, in step 290, the time when electricity starts to be applied
The energization start point is calculated from T ₀ and the period T ₂ , and the process returns to step 220.

Among the above processes, the process of step 220 corresponds to the process as a determination means, and steps 230 to 29
The process of 0 corresponds to the process as a heat generation control means.

Since this embodiment is configured in this way, the exhaust gas temperature can be almost predicted, especially in a steady medium load state where the exhaust gas temperature is relatively low and there is a risk that the oxygen concentration detection section 51 may be inactivated. In this state, the temperature of the oxygen concentration detection section 51 can be maintained in a substantially constant state by setting the expected amount of heat generation required and supplying the amount of power to the heater section 52 in anticipation. is possible. In this way, the temperature of the oxygen concentration detecting section 51 of the air-fuel ratio sensor having the heater section 52 can be made constant with a simple structure.

Further, as in the first example program, even if there is a fluctuation in the power supply voltage or a change in the resistance value of the heater section 16b over time, the power consumption detection circuit 39 detects the fluctuation change, and the energization control circuit 38 sends a signal to the heater section 16b. Since this is reflected in the amount of power supplied to the oxygen sensor, the oxygen sensor can be activated at all times, and the oxygen concentration state can be accurately determined.

In this way, the power consumption detection circuit 39 that detects the power to the heater section 16b is used to maintain the activated state of the oxygen concentration detection section 16a without using a temperature detection device. 16a
It is sufficient to simply provide a simple power consumption detection circuit 39 in the control circuit 15, which is a location other than the air-fuel ratio sensor 16, without providing a temperature detection device for the air-fuel ratio sensor 16.
Therefore, the structure of the air-fuel ratio sensor 16 is not complicated, and the activation of the oxygen concentration detecting section 16a is ensured, so that accurate output can be obtained.

〔Effect of the invention〕

The present invention calculates the amount of heat generated in the heat generating means for heating the oxygen sensor based on data detected by the operating state detecting means of the internal combustion engine, thereby eliminating the need for making the oxygen sensor a particularly complicated structure. This makes it possible to maintain the temperature of the oxygen sensor at a constant temperature higher than the activation temperature, making it easy to apply the oxygen sensor to internal combustion engines. Such a simple structure reduces failures, is easy to manufacture, has a high yield, and does not require special parts, contributing to resource conservation.

In addition, if there is a fluctuation in power due to fluctuations in power supply voltage or changes in the resistance value of the heat generating means over time,
The calorific value control means detects the fluctuation based on the output of the power detection means, and further, based on the fluctuation, the power supply adjustment means adjusts the power supplied to the heat generation means. As a result, even if there is a fluctuation in the power supply voltage or a change in the resistance value of the heat generating means over time, the oxygen sensor can always be activated and the oxygen concentration state can be accurately determined.

In this way, to maintain the activated state of the oxygen sensor, a power detection means is used for the heat generation means without using a temperature detection device, so it is possible to easily detect power without providing a temperature detection means in the oxygen sensor. It is only necessary to provide the means separately from the oxygen sensor. Therefore, it is possible to ensure activation of the oxygen sensor and obtain accurate output without complicating the structure of the oxygen sensor.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the basic configuration of the present invention, Figure 2 is a schematic diagram of the first embodiment of the present invention, and Figure 3A is a cross-sectional view of essential parts showing the structure of the air-fuel ratio sensor used therein. , Fig. 3(b) is a sectional view of a main part of an air-fuel ratio sensor having another structure, Fig. 4 is a block diagram of a control circuit used in the first embodiment, and Fig. 5 shows details of heater control of the air-fuel ratio sensor. 6 is a pulse waveform diagram showing the pulse waveform of the control signal, FIG. 7 is a block diagram showing another example of heater control for the air-fuel ratio sensor, and FIG. 8 is the configuration of yet another example of heater control. 9 is a flowchart of one control example, and FIG. 10 is a flowchart of another control example. 2... Internal combustion engine, 3... Exhaust manifold, 9... Air flow meter, 10... Intake temperature sensor, 13... Fuel injection valve, 14... Throttle opening sensor, 15... Control circuit, 16... Air-fuel ratio sensor, 16a, 51... Oxygen Concentration detection section, 16b, 52... Heater section, 37
...Microcomputer, 38...Electrification control circuit,
39...Power consumption detection circuit.

Claims (1)

[Scope of Claims] 1. Operating state detection means for detecting the operating state of the internal combustion engine; Heat generating means for heating the oxygen sensor for detecting the oxygen concentration in the exhaust gas of the internal combustion engine; Electric power supplied to the heat generating means. supply power adjusting means for adjusting the power supply according to a command signal; power detecting means for outputting a signal indicating the power actually supplied to the heat generating means; and power detecting means for outputting a signal indicating the power actually supplied to the heating means; determining means for determining whether the heating means should be heated based on the heating means; A temperature control device for an oxygen sensor, comprising: a calorific value control means that adjusts a command signal to the power supply adjustment means according to the detected power detected by the power detection means. 2. The operating state detection means includes an intake air amount detection section that detects the intake air amount of the internal combustion engine and an exhaust temperature detection section that detects the exhaust temperature, and the heat generation means includes a resistor attached to the oxygen sensor. A heating element is provided, and the heat generation amount control means sends a command signal to the power supply adjustment means based on the intake air amount detected by the intake air amount detection section and the exhaust temperature detected by the exhaust temperature detection section. 2. A temperature control device for an oxygen sensor according to claim 1, wherein the temperature control device is configured to adjust the temperature of the oxygen sensor. 3. The heat generation amount control means controls the power supply adjustment means to maintain the heat generation amount of the heat generation means at a predetermined amount when the fluctuation in the operating state detected by the operation state detection means is within a predetermined range. A temperature control device for an oxygen sensor according to claim 1, characterized in that the device is configured to adjust a command signal.