Nitrogen oxygen sensor oxygen pumping device, nitrogen oxygen sensor and oxygen pumping method thereof

Abstract

The present invention relates to the technical field of automobile exhaust treatment, and discloses a nitrogen oxygen sensor oxygen pumping device, a nitrogen oxygen sensor and an oxygen pumping method thereof. The nitrogen oxygen sensor oxygen pumping device comprises a signal processing module and an oxygen pumping module. The signal processing module is used to detect and process a pump current signal of a pump electrode and a reference induced potential signal of a reference electrode to obtain an advance oxygen pumping signal, and send the advance oxygen pumping signal to the oxygen pumping module; wherein the reference induced potential signal is generated by superimposing the potential difference generated by the oxygen concentration difference between the main pump electrode and the reference electrode on the reference electrode, and the potential of the main pump electrode is a preset value; the oxygen pumping module is used to connect the signal processing module, and is used to adjust the main pump-pump potential difference between the main pump electrode and a pump electrode according to the received advance oxygen pumping signal, so as to pump oxygen to a chamber. The nitrogen oxygen sensor oxygen pumping device provided by the present invention solves the problem of inaccurate concentration measurement of nitrogen oxides in nitrogen oxygen sensors in the prior art.

Description

Technical Field

[0001] The invention relates to the field of automobile exhaust treatment, and in particular to a nitrogen oxygen sensor oxygen pumping device, a nitrogen oxygen sensor and an oxygen pumping method thereof. Background Art

[0002] The current-type nitrogen oxide sensor is made of ceramic materials based on aluminum oxide and zirconium oxide matrix (doped with materials such as yttrium oxide). Due to its advantages of high temperature resistance, corrosion resistance, long life, and gas sensitivity, it is widely used in the detection of nitrogen oxides in diesel vehicle exhaust. The detection principle is that after exceeding 300 degrees Celsius, by applying voltage on both sides of the zirconium oxide matrix, zirconium oxide can conduct electricity through the migration of oxygen ions, thereby forming an electric current. In the exhaust process of diesel vehicles, the exhaust gas, i.e. the gas to be tested, contains nitrogen oxides, oxygen, hydrocarbons and other gases. After passing through a chamber in the nitrogen oxide sensor, the oxygen in the gas to be tested will be pumped out of the nitrogen oxide sensor under the action of voltage and high temperature, and the remaining gas to be tested will enter the second chamber in the nitrogen oxide sensor. Under the action of the catalyst, the nitrogen oxides are decomposed into oxygen and nitrogen. The decomposed oxygen will be pumped out of the nitrogen oxide sensor again. The concentration of nitrogen oxides can be calculated by the oxygen ion current generated when the decomposed oxygen is pumped out.

[0003] In the prior art, the oxygen pump response speed of the first chamber is slow, resulting in too much oxygen entering the second chamber, exceeding the oxygen pump capacity of the second chamber, causing the oxygen pump of the second chamber to be unable to maintain balance, resulting in excessive oxygen enrichment at the nitrogen oxide measurement point, and the oxygen ion current measured at the measurement point is larger than the actual oxygen ion current of the decomposition of nitrogen oxides, so that the measured concentration value of nitrogen oxides is not the true value. Summary of the invention

[0004] In view of the deficiencies in the above-mentioned prior art, the present invention provides a nitrogen oxide sensor oxygen pumping device, a nitrogen oxide sensor and an oxygen pumping method thereof, which can solve the technical problem of inaccurate concentration measurement of nitrogen oxide compounds in the nitrogen oxide sensor in the prior art.

[0005] A first aspect of the present invention provides a nitrogen oxygen sensor oxygen pump device, the device comprising:

[0006] A signal processing module, used for detecting a pump current signal of a pump electrode in the nitrogen oxygen sensor and a reference induced potential signal of a reference electrode, obtaining an advance pump oxygen signal according to the pump current signal and the reference induced potential signal, and sending the advance pump oxygen signal to the pump oxygen module; wherein the reference induced potential signal is generated by superimposing the potential difference generated by the oxygen concentration difference between the main pump electrode and the reference electrode in the nitrogen oxygen sensor on the reference electrode, and the potential of the main pump electrode is a preset value;

[0007] The oxygen pump module is used to connect to the signal processing module, and is used to adjust the main pump-pump potential difference between the main pump electrode and the first pump electrode according to the received advance oxygen pump signal, so as to adjust the oxygen ion current of the first pump electrode to pump oxygen to a chamber in the nitrogen oxide sensor.

[0008] Optionally, the device further includes a control module, which is connected to the signal processing module, and is used to detect a two-pump reference potential difference signal between the two-pump electrodes in the nitrogen oxygen sensor and the reference electrode, and a two-pump current signal of the two-pump electrodes, obtain a required adjustment signal according to the two-pump reference potential difference signal and the two-pump current signal, and send the required adjustment signal to the signal processing module; wherein the two-pump reference potential difference signal is generated by the oxygen concentration difference between the two-pump electrodes and the reference electrode;

[0009] The signal processing module is further used to obtain a feedback pump oxygen signal according to the first pump current signal, the reference induction potential signal and the received demand signal, and send the feedback pump oxygen signal to the pump oxygen module;

[0010] The oxygen pump module is further used to adjust the main pump-pump potential difference between the main pump electrode and the first pump electrode according to the received feedback oxygen pump signal, so as to adjust the oxygen ion current of the first pump electrode to pump oxygen to the first chamber until the current value of the second pump current signal reaches a preset current value and the potential difference of the second pump reference potential difference signal reaches a preset potential difference.

[0011] Optionally, the signal processing module includes a first processing module, which is used to detect and process the first pump current signal; the first processing module includes a first operational amplifier, a first resistor, a first capacitor and a second resistor;

[0012] The inverting input terminal of the first operational amplifier is used to receive the first pump current signal, and is also connected to one end of the first resistor and one end of the first capacitor respectively;

[0013] The other end of the first resistor is respectively connected to the other end of the first capacitor and the output end of the first operational amplifier;

[0014] The output end of the first operational amplifier is also connected to one end of the second resistor, and the other end of the second resistor is connected to the non-inverting input end of the first operational amplifier;

[0015] The power supply terminal of the first operational amplifier is connected to a first preset voltage, and the ground terminal thereof is grounded.

[0016] Optionally, the signal processing module further includes a second processing module for detecting and processing the reference induced potential signal; the second processing module includes a second operational amplifier, a third resistor, a fourth resistor, a second capacitor, and a fifth resistor;

[0017] The non-inverting input terminal of the second operational amplifier is used to receive the reference induced potential signal, and the inverting input terminal thereof is respectively connected to one end of the third resistor, one end of the fourth resistor, and one end of the second capacitor;

[0018] The other end of the third resistor is grounded, the other end of the fourth resistor is respectively connected to the other end of the second capacitor and one end of the fifth resistor, and the other end of the fifth resistor is connected to the output end of the second operational amplifier;

[0019] The power supply terminal of the second operational amplifier is connected to a second preset voltage, and the ground terminal thereof is grounded.

[0020] Optionally, the second processing module further includes a clamping diode, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor;

[0021] The cathode of the clamping diode is respectively connected to the other end of the second capacitor and one end of the sixth resistor, and the other end of the sixth resistor is respectively connected to the clamping end of the clamping diode and one end of the seventh resistor;

[0022] The other end of the seventh resistor is connected to the anode of the clamping diode and one end of the eighth resistor respectively, and the other end of the eighth resistor is connected to the ground terminal of the second operational amplifier;

[0023] The cathode of the clamping diode is also connected to one end of the ninth resistor, and the other end of the ninth resistor is connected to the non-inverting input end of the first operational amplifier.

[0024] Optionally, the second processing module also includes a voltage divider circuit, a first input end of the voltage divider circuit is connected to one end of the sixth resistor, a second input end of the voltage divider circuit is connected to the other end of the seventh resistor, a first output end of the voltage divider circuit is connected to the two pump electrodes, and a second output end of the voltage divider circuit is connected to the measuring electrode.

[0025] Optionally, the device further includes a tenth resistor, an eleventh resistor, a third capacitor and a fourth capacitor;

[0026] The control module is also used to connect one end of the tenth resistor, the other end of the tenth resistor is respectively connected to one end of the eleventh resistor and one end of the third capacitor, the other end of the third capacitor is grounded, the other end of the eleventh resistor is respectively connected to one end of the fourth capacitor and the non-inverting input terminal of the first operational amplifier, and the other end of the fourth capacitor is grounded.

[0027] A second aspect of the present invention provides a nitrogen oxygen sensor, comprising a core body and an oxygen pumping device as described above, wherein the oxygen pumping device is used to pump oxygen into a chamber in the core body.

[0028] A third aspect of the present invention provides an oxygen pumping method for a nitrogen oxygen sensor, the method comprising:

[0029] Detecting a pump current signal of a pump electrode in the nitrogen oxygen sensor and a reference induced potential signal of the reference electrode, and obtaining an advance pump oxygen signal according to the pump current signal and the reference induced potential signal; wherein the reference induced potential signal is generated by superimposing the potential difference generated by the oxygen concentration difference between the main pump electrode and the reference electrode in the nitrogen oxygen sensor on the reference electrode, and the potential of the main pump electrode is a preset value;

[0030] The main pump-pump potential difference between the main pump electrode and a pump electrode is adjusted according to the advance oxygen pump signal to adjust the oxygen ion current of the pump electrode to pump oxygen to a chamber in the nitrogen oxide sensor.

[0031] Optionally, the method further includes:

[0032] Detecting a two-pump reference potential difference signal between the two-pump electrodes and the reference electrode in the nitrogen oxygen sensor and a two-pump current signal of the two-pump electrodes, and obtaining a required adjustment signal according to the two-pump reference potential difference signal and the two-pump current signal; wherein the two-pump reference potential difference signal is generated by the oxygen concentration difference between the two-pump electrodes and the reference electrode;

[0033] Obtaining a feedback pump oxygen signal according to the regulation demand signal, the first pump current signal, and the reference induction potential signal;

[0034] The main pump-one pump potential difference between the main pump electrode and the one pump electrode is adjusted according to the feedback pump oxygen signal to adjust the oxygen ion current of the one pump electrode to pump oxygen to the one chamber until the current value of the two pump current signals reaches a preset current value and the potential difference of the two pump reference potential difference signals reaches a preset potential difference.

[0035] The invention discloses a nitrogen oxygen sensor oxygen pumping device, which comprises a signal processing module and an oxygen pumping module. The signal processing module is used to detect and process a pump current signal and a reference induced potential signal, and send an advance oxygen pumping signal obtained by the processing; the oxygen pumping module is used to connect the signal processing module, and is used to adjust the potential difference between a main pump electrode and a pump electrode according to the received advance oxygen pumping signal, so as to pump oxygen into a chamber. The device can change the potential difference between the main pump electrode and the pump electrode by detecting a reference induced potential signal and a pump current signal before the gas to be measured enters the second chamber, so as to pump oxygen into the first chamber, thereby reducing the oxygen concentration of the gas to be measured in the first chamber in advance, avoiding the gas to be measured with increased oxygen concentration from diffusing into the second chamber, avoiding exceeding the oxygen pumping range of the second chamber, so that the oxygen pumping of the two chambers can maintain balance, and making the concentration of nitrogen oxides measured by the measuring electrode more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic structural diagram of the core body of the nitrogen oxygen sensor provided by the present invention;

[0038] Figure 2 A schematic diagram of the structure of a nitrogen and oxygen sensor oxygen pump device provided in Embodiment 1 of the present invention;

[0039] Figure 3 A circuit diagram of a first processing module of a signal processing module in a nitrogen oxygen sensor pump oxygen device provided in Embodiment 2 of the present invention;

[0040] Figure 4 Another circuit diagram of the first processing module of the signal processing module in the nitrogen oxygen sensor pump oxygen device provided by the present invention;

[0041] Figure 5 A circuit diagram of a second processing module of a signal processing module in a nitrogen oxygen sensor pump oxygen device provided in Embodiment 3 of the present invention;

[0042] Figure 6 A working principle diagram of a control module in a nitrogen and oxygen sensor pump oxygen device provided in a fourth embodiment of the present invention;

[0043] Figure 7 This is a diagram showing the relationship between electrical parameters and oxygen concentration in the chamber of a nitrogen and oxygen sensor pump oxygen device provided in Embodiment 5 of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0045] See also Figure 1 , Figure 1 This is a schematic structural diagram of the core body of the nitrogen oxygen sensor provided by the present invention.

[0046] like Figure 1 As shown, the core body of the nitrogen oxygen sensor includes a chamber, a second chamber and a reference chamber. The core body is provided with a main pump electrode, a pump electrode, a second pump electrode, a measuring electrode, a reference electrode and a heating electrode. The pump electrode is provided in the chamber, the second pump electrode and the measuring electrode are provided in the chamber, the reference electrode is connected to the reference chamber, and the reference chamber is connected to the outside air. There is a diffusion barrier in front of the chamber, and an isolation barrier is provided between the chambers. The diffusion barrier and the isolation barrier are porous alumina, allowing the gas to be measured to enter the chambers at a certain speed.

[0047] Each electrode is connected to a different preset voltage, the potential of the main pump electrode is V0, the potential of the first pump electrode is V1, the potential of the second pump electrode is V2, the potential of the measuring electrode is V3, and the potential of the reference electrode is V4. Preferably, the value of V0 remains unchanged and is greater than the values ​​of V1, V2, and V3, and the value of V4 can be greater than, equal to, or less than the value of V0. The oxygen ion current I1 of the first pump electrode, the oxygen ion current I2 of the second pump electrode, and the oxygen ion current I3 of the measuring electrode all flow out from the main pump electrode, so the oxygen ions will gather on the main pump electrode to form oxygen and be pumped out.

[0048] In the prior art, a current is passed through the heating electrode to heat the core body, and when the temperature of the core body is between 600 and 850 degrees Celsius, the core body becomes a conductor. By applying a voltage between the electrodes in the zirconium oxide matrix, the zirconium oxide can conduct electricity through the migration of oxygen ions, thereby forming an oxygen ion current, that is, the oxygen in the gas to be measured in the first chamber and the second chamber can be pumped out of the core body in the form of an oxygen ion current, so that the gas to be measured entering the second chamber contains almost no oxygen, but only nitrogen oxides, which are decomposed into nitrogen and oxygen by the catalytic reduction reaction of the catalyst on the measuring electrode. The decomposed oxygen is pumped out of the core body under the action of the voltage between the main pump electrode and the measuring electrode, and the concentration of nitrogen oxides in the gas to be measured can be calculated according to the amount of oxygen pumped out at the measuring electrode. The oxygen concentration in the gas to be measured in the first chamber and the second chamber and the concentration of nitrogen oxides can be calculated by measuring the size of the oxygen ion current of each electrode. Among them, the oxygen in the gas to be measured in the first chamber cannot be completely pumped out, otherwise the nitrogen oxides will be decomposed into nitrogen and oxygen in the first chamber.

[0049] In the prior art, a voltage is applied to a pump electrode to pump out the oxygen in the gas to be tested, and the oxygen content is controlled at 3-5 ppm by volume (to prevent nitrogen oxides from undergoing a reduction reaction in the first chamber). After the gas to be tested enters the second chamber, the second pump electrode continues to pump out the oxygen entering the first chamber, so that the oxygen content in the second chamber approaches 10-3 ppm by volume, thereby preventing the oxygen in the gas to be tested from entering the measuring electrode and affecting the test results.

[0050] In the prior art, the oxygen ion current I2 of the second pump electrode is used to determine whether the oxygen concentration of the gas to be measured entering the second chamber has changed, thereby controlling the main pump-one pump potential difference V01 between the main pump electrode and the first pump electrode in the first chamber to pump oxygen, thereby adjusting the oxygen concentration of the gas to be measured entering the second chamber. However, before the change of the oxygen ion current I2 of the second pump electrode is detected, the oxygen concentration of the gas to be measured entering the second chamber has changed, which will cause the oxygen ion current I3 of the measuring electrode in the second chamber to change, and the calculated concentration of nitrogen oxides in the gas to be measured will also be inaccurate. Therefore, there is a technical defect in the prior art that the second chamber senses the change of oxygen concentration lagging.

[0051] It should be noted that when the potential difference between the two electrodes is constant, the greater the oxygen concentration, the greater the oxygen ion current. When the oxygen concentration between the two electrodes is constant, the greater the potential difference, the greater the oxygen ion current.

[0052] The greater (or smaller) the oxygen concentration difference between the other electrodes (e.g., the main pump electrode, the first pump electrode, the second pump electrode, the measuring electrode) and the reference electrode, the smaller (or larger) the potential difference between the other electrodes and the reference electrode according to the Nernst principle. There is only a potential difference between the other electrodes and the reference electrode, and no current exists. The reference electrode is connected to the air, and the oxygen concentration in the air is between 19.5% and 23.5%. In some embodiments of the present application, the oxygen concentration in the reference chamber is always 20.9%, and the oxygen concentration at the other electrodes is usually less than the oxygen concentration in the air.

[0053] It should be noted that the exhaust gas, i.e. the gas to be tested, gradually enters the chamber of the nitrogen oxygen sensor core body in steps by diffusion. The gas to be tested enters the nitrogen oxygen sensor core body in three stages in chronological order. Stage 1: The gas to be tested diffuses on the head surface of the core body; Stage 2: The gas to be tested enters the first chamber through the isolation barrier in front of the first chamber; Stage 3: The gas to be tested passes through the diffusion barrier behind the first chamber and enters the second chamber.

[0054] When the oxygen concentration of the gas to be measured changes, in the first stage, the oxygen in the gas to be measured first diffuses on the substrate near the main pump electrode. According to the Nernst principle, the voltage V04 between the main pump electrode and the reference electrode changes at this stage. Since the potential V0 of the main pump electrode remains unchanged, the potential V4 of the reference electrode changes at this stage. In the second stage, after the gas to be measured diffuses into the first chamber, the oxygen concentration of the first chamber changes, causing the oxygen ion current I1 of the first pump electrode to change at this stage. In the third stage, after the gas to be measured enters the second chamber, the oxygen concentration in the second chamber changes. At this stage, the oxygen ion current I2 of the second pump electrode changes. Of course, according to the Nernst principle, the voltage V24 between the second pump electrode and the reference electrode also changes.

[0055] See also Figure 2 , Figure 2 This is a schematic structural diagram of a nitrogen oxygen sensor oxygen pump device provided in Embodiment 1 of the present invention.

[0056] The first aspect of the present invention provides a nitrogen oxygen sensor pump oxygen device, such as Figure 2 As shown, the device includes a signal processing module 1 and an oxygen pump module 2, wherein:

[0057] The signal processing module 1 is used to detect and process a pump current signal of a pump electrode in the nitrogen oxygen sensor and a reference induced potential signal of a reference electrode, and send the processed advance pump oxygen signal to the pump oxygen module 2. Among them, the potential V0 of the main pump electrode is a preset value, and the preset value is selected as 2.0 volts-2.5 volts. The reference induced potential signal is generated by applying the potential difference generated by the oxygen concentration difference between the main pump electrode and the reference electrode to the reference electrode.

[0058] It should be noted that both the main pump electrode and the reference electrode are connected to a preset voltage, and there is already a potential difference between the two electrodes. According to the Nernst principle, when there is an oxygen concentration difference between the main pump electrode and the reference electrode, a potential difference will be induced between the main pump electrode and the reference electrode. Since the potential V0 of the main pump electrode remains unchanged, the induced potential difference will be superimposed on the reference electrode to form the potential V4 of the reference electrode. The detected reference induced potential signal is the signal of the potential V4 of the reference electrode.

[0059] Better, combined Figure 1 to Figure 2 , the potential V0 of the main pump electrode remains unchanged. When the oxygen concentration difference between the main pump electrode and the reference electrode changes, according to the Nernst principle, the potential V4 of the reference electrode changes. When the oxygen concentration of the gas to be measured entering a chamber changes, the oxygen ion current I1 of the pump electrode will also change. Therefore, according to the above principle description, in the first stage and the second stage, when the oxygen concentration of the gas to be measured changes, the oxygen ion current I1 of the pump electrode and the potential V4 of the reference electrode will change.

[0060] Correspondingly, a pump current signal is a signal of an oxygen ion current I1 of a pump electrode, and a reference induced potential signal is a signal of a potential V4 of a reference electrode. By detecting an oxygen ion current I1 of a pump electrode and a potential V4 of a reference electrode, it is known that the oxygen concentration of the gas to be measured has changed, and oxygen can be pumped into a chamber in advance to prevent the gas to be measured with a changed oxygen concentration from entering the second chamber.

[0061] like Figure 1 to Figure 2 As shown, the oxygen pump module 2 is used to connect to the signal processing module 1, and is used to adjust the main pump-pump potential difference V01 between the main pump electrode and the first pump electrode according to the received advance oxygen pump signal, so as to adjust the oxygen ion current I1 of the first pump electrode to pump oxygen to a chamber in the nitrogen oxygen sensor.

[0062] In fact, the potential V0 of the main pump electrode is constant, so only the potential V1 of a pump electrode needs to be adjusted to change the potential difference V01 between the main pump electrode and a pump electrode, thereby changing the oxygen ion current I1 of a pump electrode and changing the oxygen pumping rate of a chamber.

[0063] For example, when the oxygen concentration of the gas to be measured increases and the gas to be measured diffuses on the matrix surface of the main pump electrode, due to the electromagnetic force of the potential V0 applied to the main pump electrode, oxygen will be adsorbed on the main pump electrode, and the oxygen concentration at the main pump electrode will increase. According to the Nernst principle, the potential difference between the main pump electrode and the reference electrode becomes smaller, while the potential V0 of the main pump electrode remains unchanged, then the potential V4 of the reference electrode becomes smaller.

[0064] For example, the potential V0 of the main pump electrode is a constant value of 2.3 volts. When the oxygen concentration at the main pump electrode is 0, 10%, and 20.9%, respectively, the potential difference V04 generated by the oxygen concentration difference between the main pump electrode and the reference electrode is -0.2 volts, -0.1 volts, and 0 volts, respectively, and the potential V4 of the reference electrode is 2.5 volts, 2.4 volts, and 2.3 volts, respectively.

[0065] Because the gas to be measured diffuses on the substrate surface of the main pump electrode before entering a chamber, by detecting the changed potential V4 of the reference electrode, the change in the oxygen concentration of the gas to be measured can be known in advance, so as to prepare for pumping oxygen in advance.

[0066] The gas to be measured continues to enter the first chamber, the oxygen concentration increases, and the main pump-one pump potential difference V01 between the main pump electrode and the first pump electrode remains unchanged, so the oxygen ion current I1 of the first pump electrode increases.

[0067] At this time, the oxygen concentration of the gas to be measured increases, causing the oxygen ion current I1 of the first pump electrode to increase and the potential V4 of the reference electrode to decrease. By detecting the oxygen ion current I1 of the first pump electrode and the potential V4 of the reference electrode, the main pump-pump potential difference V01 between the main pump electrode and the first pump electrode can be increased by reducing the potential V1 of the first pump electrode, thereby increasing the oxygen ion current I1 of the first pump electrode, speeding up the oxygen pumping of the first chamber, and reducing the oxygen concentration of the gas to be measured in the first chamber, thereby preventing the gas to be measured with increased oxygen concentration from diffusing into the second chamber.

[0068] The invention discloses a nitrogen oxygen sensor oxygen pumping device, which comprises a signal processing module and an oxygen pumping module. The signal processing module is used to detect and process a pump current signal and a reference induced potential signal, and send an advance oxygen pumping signal obtained by the processing; the oxygen pumping module is used to connect the signal processing module, and is used to adjust the potential difference between a main pump electrode and a pump electrode according to the received advance oxygen pumping signal, so as to pump oxygen into a chamber. The device can change the potential difference between the main pump electrode and the pump electrode by detecting a reference induced potential signal and a pump current signal before the gas to be measured enters the second chamber, so as to pump oxygen into the first chamber, thereby reducing the oxygen concentration of the gas to be measured in the first chamber in advance, avoiding the gas to be measured with increased oxygen concentration from diffusing into the second chamber, avoiding exceeding the oxygen pumping range of the second chamber, so that the oxygen pumping of the two chambers can maintain balance, and making the concentration of nitrogen oxides measured by the measuring electrode more accurate.

[0069] Further, such as Figure 2As shown, the device also includes a control module 3, which is used to connect the signal processing module 1, and is used to detect the two-pump reference potential difference signal between the two-pump electrode and the reference electrode, the two-pump current signal of the two-pump electrode, obtain the required adjustment signal according to the two-pump reference potential difference signal and the two-pump current signal, and send the required adjustment signal to the signal processing module. Among them, the two-pump reference potential difference signal is generated by the oxygen concentration difference between the two-pump electrode and the reference electrode. The two-pump current signal is the signal of the oxygen ion current I2 of the two-pump electrode.

[0070] The control module 3 can be a single-chip microcomputer, FPGA (Field Programmable Gate Array), PLC (Programmable Logic Controller), ECU (Electronic Control Unit), DCU (Drive Control Unit), etc. Preferably, ECU or DCU can be selected as the control module 3 in this embodiment.

[0071] The signal processing module 1 is also used to obtain a feedback pump oxygen signal according to a pump current signal, a reference induction potential signal and a received adjustment signal, and to send the feedback pump oxygen signal. The adjustment signal here is a voltage signal.

[0072] The oxygen pump module 2 is also used to adjust the main pump-pump potential difference V01 between the main pump electrode and the first pump electrode according to the received feedback oxygen pump signal to pump oxygen to a chamber until the current value of the second pump current signal reaches a preset current value and the potential difference of the second pump reference potential difference signal reaches a preset potential difference.

[0073] Preferably, the reference potential difference V24 of the two pumps reaches a preset potential difference, which is a constant value between 410 mV and 450 mV, and the current value of the oxygen ion current I2 of the two pump electrodes reaches a preset current value, which is a constant value between 5 μA and 9 μA.

[0074] Furthermore, the device also includes a power supply module ( Figure 2 The power supply module is used to supply power to the signal processing module 1. Preferably, the power supply module is also used to supply power to the control module 3.

[0075] Furthermore, the control module 3 outputs the modulation signal in the form of PWM (Pulse width modulation).

[0076] See also Figure 3 , Figure 3 This is a circuit diagram of a first processing module of a signal processing module in a nitrogen oxygen sensor pump oxygen device according to a second embodiment of the present invention.

[0077] Further, such as Figure 3 As shown, the signal processing module 1 includes a first processing module for detecting and processing a pump current signal. The first processing module includes a first operational amplifier A1, a first resistor R1, a first capacitor C1 and a second resistor R2.

[0078] The inverting input terminal of the first operational amplifier A1 is used to receive a pump current signal, and is also connected to one end of the first resistor R1 and one end of the first capacitor C1 respectively.

[0079] The other end of the first resistor R1 is connected to the other end of the first capacitor C1 and the output end of the first operational amplifier A1 respectively.

[0080] The output end of the first operational amplifier A1 is also connected to one end of the second resistor R2. Figure 3 The A terminal in is connected to the non-inverting input terminal of the first operational amplifier A1, and is used to superimpose a potential output converted from a pump current signal on a potential V1 of a pump electrode.

[0081] The power supply terminal of the first operational amplifier A1 is connected to a first preset voltage, and the ground terminal thereof is grounded, wherein the first preset voltage is 3V-30V.

[0082] See also Figure 4 , Figure 4 Another circuit diagram of the first processing module of the signal processing module in the nitrogen oxygen sensor pump oxygen device provided by the present invention.

[0083] like Figure 4 As shown, in the prior art, compared with Figure 3 The first processing module also includes a third operational amplifier A3 and a twelfth resistor R12.

[0084] A non-inverting input terminal of the third operational amplifier A3 is respectively connected to the output terminal of the first operational amplifier A1 and one end of a twelfth resistor R12, and the other end of the twelfth resistor R12 is grounded.

[0085] The inverting input terminal of the third operational amplifier A3 is connected to the output terminal of the third operational amplifier A3 and one end of the second resistor respectively.

[0086] The power supply terminal of the third operational amplifier A3 is connected to a third preset voltage, and the ground terminal thereof is grounded, wherein the third preset voltage is 3V-30V.

[0087] Figure 4 The third operational amplifier A3 and the twelfth resistor R12 in the prior art shown in the figure are used to convert the current input to the non-inverting input terminal thereof into a potential output. Figure 3In the embodiment of the present application shown, the third operational amplifier A3 and the twelfth resistor R12 are removed, and the current output from the output end of the first operational amplifier A1 flows through the second resistor R2 to be converted into a potential and directly output to the non-inverting input end of the first operational amplifier A1. Figure 4 The prior art in Figure 3 The first processing module provided in the embodiment of the present application has a simple structure and low cost. Since an operational amplifier and a resistor are removed, the error amplification rate caused by the complex circuit structure is reduced, making the potential output by the first processing module more stable.

[0088] It should be noted that, in the prior art, at least two operational amplifiers are usually required to convert the oxygen ion current I1 of a pump electrode and feed it back to the potential V1 of a pump electrode. However, the present application only requires one operational amplifier to convert the oxygen ion current I1 of a pump electrode and feed it back to the potential V1 of a pump electrode, thereby reducing the noise interference caused by too many operational amplifiers and improving the oxygen pump response speed.

[0089] See also Figure 5 , Figure 5 This is a circuit diagram of the second processing module of the signal processing module in the nitrogen oxygen sensor pump oxygen device provided in the third embodiment of the present invention.

[0090] Further, such as Figure 5 As shown, the signal processing module 1 also includes a second processing module for detecting and processing the reference induced potential signal. The second processing module includes a second operational amplifier A2, a third resistor R3, a fourth resistor R4, a second capacitor C2, and a fifth resistor R5. The function of the second processing module here is to amplify the potential V4 of the reference electrode and perform RC (Resistor Capacitance, resistor and capacitor) filtering, with an amplification factor of 1-2 times.

[0091] The non-inverting input terminal of the second operational amplifier A2 is used to receive the reference induced potential signal, and the inverting input terminal thereof is respectively connected to one end of the third resistor R3, one end of the fourth resistor R4, and one end of the second capacitor C2.

[0092] The other end of the third resistor R3 is grounded, the other end of the fourth resistor R4 is respectively connected to the other end of the second capacitor C2 and one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the output end of the second operational amplifier A2.

[0093] The power supply terminal of the second operational amplifier A2 is connected to a second preset voltage, and the ground terminal thereof is grounded, wherein the second preset voltage is 3V-30V.

[0094] Further, such as Figure 5As shown, the second processing module further includes a clamping diode D, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. The function of the components added to the second processing module here is to clamp the potential V4 of the reference electrode after amplification and filtering.

[0095] The cathode of the clamping diode D is respectively connected to the other end of the second capacitor C2 and one end of the sixth resistor R6 , and the other end of the sixth resistor R6 is respectively connected to the clamping end of the clamping diode D and one end of the seventh resistor R7 .

[0096] The other end of the seventh resistor R7 is connected to the anode of the clamping diode D and one end of the eighth resistor R8 respectively, and the other end of the eighth resistor R8 is connected to the ground end of the second operational amplifier A2.

[0097] The cathode of the clamping diode D is also connected to one end of the ninth resistor R9, and the other end of the ninth resistor R9 is Figure 4 The B terminal in is connected to the non-inverting input terminal of the first operational amplifier A1, and is used to superimpose the potential output obtained by converting the reference induced potential signal onto the potential V1 of a pump electrode.

[0098] Further, such as Figure 5 As shown, the second processing module also includes a voltage divider circuit for dividing the potential V4 of the clamped reference electrode. The first input end of the voltage divider circuit is connected to one end of the sixth resistor R6, the second input end is connected to the other end of the seventh resistor R7, the first output end, i.e., the D end, is connected to the second pump electrode to output the potential V2 of the second pump electrode, and the second output end, i.e., the E end, is connected to the measuring electrode to output the potential V3 of the measuring electrode.

[0099] like Figure 6 As shown, Figure 6 This is a working principle diagram of a control module in a nitrogen oxygen sensor pump oxygen device provided in Embodiment 4 of the present invention.

[0100] Further, such as Figure 6 As shown, the device further includes a tenth resistor R10, an eleventh resistor R11, a third capacitor C3 and a fourth capacitor C4.

[0101] The control module 3 is also used to connect one end of the tenth resistor R10, the other end of the tenth resistor R10 is respectively connected to one end of the eleventh resistor R11 and one end of the third capacitor C3, the other end of the third capacitor C3 is grounded, the other end of the eleventh resistor R11 is respectively connected to one end of the fourth capacitor C4 and the non-inverting input end of the first operational amplifier A1, and the other end of the fourth capacitor C4 is grounded.

[0102] The control module 3 is used to detect the two-pump current signal and the two-pump reference potential difference signal, and obtain the required adjustment signal according to the two-pump current signal and the two-pump reference potential difference signal. It should be noted that the required adjustment signal output by the control module 3 is a PWM square wave current signal, which is filtered by the tenth resistor R10, the eleventh resistor R11, the third capacitor C3 and the fourth capacitor C4 to form a potential and output the potential V1 superimposed on the first pump electrode.

[0103] It should be noted that if Figure 3 , Figure 5 and Figure 6 As shown, Figure 3 The A end of Figure 5 The B-side and Figure 6 The C-terminals in the Figure 3 The non-inverting input terminal of the first operational amplifier A1 is used to convert the potential obtained by converting the first pump current signal, the potential obtained by converting the reference induced potential signal, and the potential obtained by converting the second pump current signal and the second pump reference potential difference signal into the required signal and filtering, and superimpose them on the potential V1 of the first pump electrode. Therefore, when the detected first pump current signal, reference induced potential signal, second pump current signal and second pump reference potential difference signal change, the main pump-one pump potential difference between the main pump electrode and the first pump electrode can be changed by changing the potential V1 formed by superimposing on the first pump potential, so as to pump oxygen to the first chamber, thereby reducing the oxygen concentration of the gas to be measured in the first chamber in advance, avoiding the diffusion of the gas to be measured with increased oxygen concentration into the second chamber, avoiding exceeding the pump oxygen range of the second chamber, so that the pump oxygen of the second chamber can maintain balance, and the concentration of nitrogen oxides measured by the measuring electrode is more accurate.

[0104] In an embodiment of the present invention, by controlling the potential V1 of a pump electrode and the oxygen ion current I1, the two-pump reference potential difference V24 between the two pump electrodes and the reference electrode, and the oxygen ion current I2 of the two pump electrodes, the pump oxygen in the first chamber and the second chamber is caused to reach a balance, thereby completing the measurement of the concentration of nitrogen oxides in the gas to be measured.

[0105] As the gas to be tested enters the first chamber and the second chamber in turn through diffusion, the dynamic balance of oxygen in the second chamber is broken, and there are only two ways to pump oxygen in the chamber. One way is to change the oxygen pumping capacity of the first chamber by applying voltage to the first pump electrode of the first chamber and changing the main pump-pump potential difference V01 between the main pump electrode and the first pump electrode. The larger the main pump-pump potential difference V01 between the main pump electrode and the first pump electrode, the stronger the oxygen pumping capacity (that is, the larger the oxygen ion current I1 of the first pump electrode). The other way is to change the oxygen pumping capacity by applying voltage to the second pump electrode of the second chamber and changing the voltage between the main pump and the second pump electrode. Since the oxygen pumping capacity of the second chamber is limited, the change in oxygen concentration is mainly completed by pumping oxygen in the first chamber.

[0106] See also Figure 7 , Figure 7 This is a diagram showing the relationship between electrical parameters and oxygen concentration in the chamber of a nitrogen and oxygen sensor pump oxygen device provided in Embodiment 5 of the present invention.

[0107] For example, Figure 7 As shown, the change of oxygen concentration in the gas to be measured first causes the change of oxygen ion current I1 of the first pump electrode and the change of reference induced potential V04 between the main pump electrode and the reference electrode. After signal operation processing, an advance pump oxygen signal is obtained, which is directly input to the first pump electrode without feedback adjustment, and the main pump-pump potential difference V01 between the main pump electrode and the first pump electrode is adjusted in advance, so that the oxygen concentration of the gas to be measured entering the second chamber through the first chamber is maintained within the oxygen pumping capacity range of the second chamber. The control module 3 measures the oxygen ion current I2 of the second pump electrode of the second chamber to calculate the required adjustment voltage, and then feeds it back to the first pump electrode after signal processing together with the oxygen ion current I1 of the first pump electrode and the reference induced potential V04 between the main pump electrode and the reference electrode, and fine-tunes the potential V1 of the first pump electrode, which is equivalent to fine-tuning the main pump-pump potential difference V01 between the main pump electrode and the first pump electrode, so that the oxygen concentration of the two chambers is in a dynamic balance.

[0108] In one embodiment of the present invention, in order to maintain the oxygen balance of the two chambers, it is necessary to maintain the two-pump reference potential difference V24 between the two-pump electrode and the reference electrode and the oxygen ion current I2 of the two-pump electrode at a constant value by a control method. Figure 6 As shown, the reference potential difference V24 of the two pumps is a constant value between 410 mV and 450 mV, and the oxygen ion current I2 of the two pump electrodes is a constant value between 5 μA and 9 μA.

[0109] In circuit design, the voltage V0 of the main pump electrode to ground is fixed at a constant value between 2V and 2.5V. The change of the reference electrode potential in the first stage of diffusion reflects the change of oxygen concentration in the gas to be measured. Figure 7 The potential difference V04 between the main pump electrode and the reference electrode is positively correlated with the potential difference V01 between the main pump electrode and the first pump electrode, so the potential V4 of the reference electrode is also positively correlated with the potential V1 of the first pump electrode. In order to maintain the reference potential difference V24 of the two pumps at a constant value between 410 mV and 450 mV, a voltage regulator is used in the circuit design to always clamp the reference potential difference V24 of the two pumps at a constant value between the two pumps.

[0110] pass Figure 5The amplification, clamping and voltage division functions of the second processing module make the potential difference V24 between the voltage input terminal of the second pump electrode and the voltage input terminal of the reference electrode a constant value between 410 mV and 450 mV. Therefore, the change of the potential V2 of the second pump electrode is automatically adjusted by the change of the potential V4 of the reference electrode, and no other intervention is required.

[0111] In passing Figure 3 and Figure 5 The voltage of the first pump electrode is superimposed as the voltage for advance regulation, so that the main pump potential difference V01 of the first chamber oxygen pump changes, thereby changing the oxygen pumping capacity, and the oxygen concentration of the first chamber is advanced regulated. After the regulation, the oxygen concentration entering the second chamber is within the regulation capacity range. The oxygen ion current I2 of the second pump electrode is measured and input to the control module 3. After the control module 3 is regulated by PID (Proportion Integral Differential), it outputs the voltage signal to be regulated in the form of PWM wave. Figure 6 After two-stage RC filtering, the C terminal inputs Figure 3 The A end of the chamber is used to fine-tune the oxygen pump potential difference in the first chamber to maintain the oxygen pump balance between the first chamber and the second chamber.

[0112] The present invention discloses a nitrogen oxygen sensor oxygen pumping device, which includes a signal processing module and an oxygen pumping module. The signal processing module is used to detect and process a pump current signal and a reference induced potential signal, and send the processed advance oxygen pumping signal; the oxygen pumping module is used to connect the signal processing module, and is used to adjust the potential difference between the main pump electrode and the first pump electrode according to the received advance oxygen pumping signal, so as to pump oxygen to a chamber. Before the gas to be measured enters the second chamber, the device can determine whether the oxygen concentration of the gas to be measured changes by detecting the reference induced potential signal and the first pump current signal. If it changes, the potential difference between the main pump electrode and the first pump electrode is changed to pump oxygen to the first chamber, thereby reducing the oxygen concentration of the gas to be measured in the first chamber in advance, and preventing the gas to be measured with increased oxygen concentration from diffusing into the second chamber. The device can pump oxygen to the first chamber in advance, avoid excessive oxygen from entering the second chamber, and avoid exceeding the oxygen pumping range of the second chamber, so that the oxygen pumping of the two chambers can maintain balance, so that the concentration of nitrogen oxides measured by the measuring electrode is more accurate.

[0113] A second aspect of the present invention provides a nitrogen oxygen sensor, comprising a core body and any one of the above-mentioned oxygen pumping devices, wherein the oxygen pumping device is used to pump oxygen into a chamber in the core body.

[0114] The structure and working principle of the oxygen pumping device are exactly the same as those of the oxygen pumping device provided in the first aspect of the present invention, and will not be described in detail here.

[0115] A third aspect of the present invention provides an oxygen pumping method for a nitrogen oxygen sensor, the method comprising:

[0116] A pump current signal and a reference induction potential signal in the nitrogen oxide sensor are detected and processed to obtain an advance pump oxygen signal. Among them, the potential V0 of the main pump electrode in the nitrogen oxide sensor is a preset value, and the reference induction potential signal is generated by superimposing the potential difference generated by the oxygen concentration difference between the main pump electrode and the reference electrode on the reference electrode.

[0117] The main pump-to-pump potential difference V01 between the main pump electrode and the first pump electrode is adjusted according to the advance oxygen pump signal to adjust the oxygen ion current I1 of the first pump electrode to pump oxygen into a chamber in the nitrogen oxygen sensor to prevent the gas to be tested with a changed oxygen concentration from entering the second chamber.

[0118] Furthermore, the method further comprises:

[0119] The two-pump reference potential difference signal and the two-pump current signal between the two-pump electrode and the reference electrode in the nitrogen oxygen sensor are detected, and the adjustment signal is obtained according to the two-pump reference potential difference signal and the two-pump current signal. Among them, the two-pump reference potential difference signal is generated by the oxygen concentration difference between the two-pump electrode and the reference electrode.

[0120] The feedback pump oxygen signal is obtained by processing the demand signal, a pump current signal and a reference induction potential signal.

[0121] The main pump-pump potential difference V01 between the main pump electrode and the first pump electrode is adjusted according to the feedback pump oxygen signal to adjust the oxygen ion current I1 of the first pump electrode to pump oxygen to a chamber until the current value of the second pump current signal reaches a preset current value and the potential difference of the second pump reference potential difference signal reaches a preset potential difference.

[0122] Preferably, the reference potential difference V24 of the two pumps reaches a preset potential difference, which is a constant value between 410 mV and 450 mV, and the current value of the oxygen ion current I2 of the two pump electrodes reaches a preset current value, which is a constant value between 5 μA and 9 μA.

[0123] The present invention discloses a method for pumping oxygen of a nitrogen oxide sensor, the method comprising: detecting a pump current signal of a pump electrode and a reference induced potential signal of a reference electrode, obtaining an advance pump oxygen signal according to the pump current signal and the reference induced potential signal, adjusting a main pump-pump potential difference between a main pump electrode and a pump electrode according to the advance pump oxygen signal, so as to pump oxygen to a chamber, thereby reducing the oxygen concentration of a gas to be measured in the chamber in advance, avoiding the gas to be measured with increased oxygen concentration from diffusing into a second chamber, avoiding exceeding the pump oxygen range of the second chamber, so that the pump oxygen of the two chambers can maintain balance, and making the concentration of nitrogen oxides measured by the measuring electrode more accurate.

[0124] In the above embodiments, the description of each embodiment has its own emphasis. For the part not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The above is a description of the nitrogen oxide sensor oxygen pumping device, nitrogen oxide sensor and oxygen pumping method provided by the present invention. For those skilled in the art, according to the idea of ​​the embodiment of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A nitrogen oxygen sensor oxygen pump device, characterized in that: The device includes a signal processing module, an oxygen pump module, and a control module, wherein: The signal processing module is used to detect a pump current signal of a pump electrode in the nitrogen oxygen sensor and a reference induced potential signal of a reference electrode, obtain an advance pump oxygen signal according to the pump current signal and the reference induced potential signal, and send the advance pump oxygen signal to the pump oxygen module; wherein the reference induced potential signal is generated by superimposing the potential difference generated by the oxygen concentration difference between the main pump electrode and the reference electrode in the nitrogen oxygen sensor on the reference electrode, and the potential of the main pump electrode is a preset value; The oxygen pump module is connected to the signal processing module and is used to adjust the main pump-pump potential difference between the main pump electrode and the first pump electrode according to the received advance oxygen pump signal, so as to adjust the oxygen ion current of the first pump electrode to pump oxygen to a chamber in the nitrogen oxide sensor; The control module is used to connect the signal processing module, and is used to detect the two-pump reference potential difference signal between the two-pump electrode and the reference electrode in the nitrogen oxygen sensor, and the two-pump current signal of the two-pump electrode, and obtain the required adjustment signal according to the two-pump reference potential difference signal and the two-pump current signal, and send it to the signal processing module so that the signal processing module can obtain the feedback pump oxygen signal according to the one-pump current signal, the reference induced potential signal and the received required adjustment signal, and send it to the pump oxygen module; and also make the pump oxygen module according to the feedback The pump oxygen signal adjusts the main pump-one pump potential difference between the main pump electrode and the one pump electrode to adjust the oxygen ion current of the one pump electrode to pump oxygen to the one chamber until the current value of the two pump current signals reaches a preset current value and the potential difference of the two pump reference potential difference signals reaches a preset potential difference; wherein the two pump reference potential difference signals are generated by the oxygen concentration difference between the two pump electrodes and the reference electrode, the potential of the main pump electrode is greater than the potential of the one pump electrode, the two pump electrodes, and the measuring electrode, and the potential of the reference electrode is greater than, equal to, or less than the potential of the main pump electrode.

2. The nitrogen oxygen sensor oxygen pump device according to claim 1, characterized in that: The signal processing module includes a first processing module for detecting and processing the first pump current signal; the first processing module includes a first operational amplifier, a first resistor, a first capacitor and a second resistor; The inverting input terminal of the first operational amplifier is used to receive the first pump current signal, and is also connected to one end of the first resistor and one end of the first capacitor respectively; The other end of the first resistor is respectively connected to the other end of the first capacitor and the output end of the first operational amplifier; The output end of the first operational amplifier is also connected to one end of the second resistor, and the other end of the second resistor is connected to the non-inverting input end of the first operational amplifier; The power supply terminal of the first operational amplifier is connected to a first preset voltage, and the ground terminal thereof is grounded.

3. The nitrogen oxygen sensor oxygen pump device according to claim 2, characterized in that: The signal processing module further includes a second processing module for detecting and processing the reference induced potential signal; the second processing module includes a second operational amplifier, a third resistor, a fourth resistor, a second capacitor, and a fifth resistor; The non-inverting input terminal of the second operational amplifier is used to receive the reference induced potential signal, and the inverting input terminal thereof is respectively connected to one end of the third resistor, one end of the fourth resistor, and one end of the second capacitor; The other end of the third resistor is grounded, the other end of the fourth resistor is respectively connected to the other end of the second capacitor and one end of the fifth resistor, and the other end of the fifth resistor is connected to the output end of the second operational amplifier; The power supply terminal of the second operational amplifier is connected to a second preset voltage, and the ground terminal thereof is grounded.

4. The nitrogen oxygen sensor oxygen pump device according to claim 3, characterized in that: The second processing module further includes a clamping diode, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor; The cathode of the clamping diode is respectively connected to the other end of the second capacitor and one end of the sixth resistor, and the other end of the sixth resistor is respectively connected to the clamping end of the clamping diode and one end of the seventh resistor; The other end of the seventh resistor is connected to the anode of the clamping diode and one end of the eighth resistor respectively, and the other end of the eighth resistor is connected to the ground terminal of the second operational amplifier; The cathode of the clamping diode is also connected to one end of the ninth resistor, and the other end of the ninth resistor is connected to the non-inverting input end of the first operational amplifier.

5. The nitrogen oxygen sensor oxygen pump device according to claim 4, characterized in that: The second processing module also includes a voltage divider circuit, a first input end of the voltage divider circuit is connected to one end of the sixth resistor, a second input end of the voltage divider circuit is connected to the other end of the seventh resistor, a first output end of the voltage divider circuit is connected to the two pump electrodes, and a second output end of the voltage divider circuit is connected to the measuring electrode.

6. The nitrogen oxygen sensor oxygen pump device according to claim 5, characterized in that: The device also includes a tenth resistor, an eleventh resistor, a third capacitor and a fourth capacitor; The control module is also used to connect one end of the tenth resistor, the other end of the tenth resistor is respectively connected to one end of the eleventh resistor and one end of the third capacitor, the other end of the third capacitor is grounded, the other end of the eleventh resistor is respectively connected to one end of the fourth capacitor and the non-inverting input terminal of the first operational amplifier, and the other end of the fourth capacitor is grounded.

7. A nitrogen oxygen sensor, characterized in that: It comprises a core body and an oxygen pumping device as described in any one of claims 1 to 6, wherein the oxygen pumping device is used to pump oxygen into a chamber in the core body.

8. A method for pumping oxygen for a nitrogen oxygen sensor, applied to the oxygen pumping device as claimed in any one of claims 1 to 6, characterized in that: The method includes: Detecting a pump current signal of a pump electrode in the nitrogen oxygen sensor and a reference induced potential signal of the reference electrode, and obtaining an advance pump oxygen signal according to the pump current signal and the reference induced potential signal; wherein the reference induced potential signal is generated by superimposing the potential difference generated by the oxygen concentration difference between the main pump electrode and the reference electrode in the nitrogen oxygen sensor on the reference electrode, and the potential of the main pump electrode is a preset value; adjusting a main pump-pump potential difference between the main pump electrode and a pump electrode according to the advance oxygen pump signal to adjust an oxygen ion current of the pump electrode to pump oxygen to a chamber in the nitrogen oxide sensor; Detecting a two-pump reference potential difference signal between the two-pump electrodes and the reference electrode in the nitrogen oxygen sensor and a two-pump current signal of the two-pump electrodes, and obtaining a required adjustment signal according to the two-pump reference potential difference signal and the two-pump current signal; wherein the two-pump reference potential difference signal is generated by the oxygen concentration difference between the two-pump electrodes and the reference electrode; Obtaining a feedback pump oxygen signal according to the regulation demand signal, the first pump current signal, and the reference induction potential signal; The main pump-one pump potential difference between the main pump electrode and the one pump electrode is adjusted according to the feedback pump oxygen signal to adjust the oxygen ion current of the one pump electrode to pump oxygen to the one chamber until the current value of the two pump current signals reaches a preset current value and the potential difference of the two pump reference potential difference signals reaches a preset potential difference.

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