CN216955839U

CN216955839U - Nitrogen and oxygen sensor oxygen pumping device and nitrogen and oxygen sensor

Info

Publication number: CN216955839U
Application number: CN202120845756.1U
Authority: CN
Inventors: 张敏环
Original assignee: Wuhan Liangan Technology Co ltd
Current assignee: Wuhan Liangan Technology Co ltd
Priority date: 2021-04-23
Filing date: 2021-04-23
Publication date: 2022-07-12
Anticipated expiration: 2031-04-23

Abstract

The utility model relates to the technical field of automobile exhaust treatment, and discloses a nitrogen-oxygen sensor oxygen pumping device and a nitrogen-oxygen sensor, wherein the nitrogen-oxygen sensor oxygen pumping device comprises a signal processing module and an oxygen pumping module, the signal processing module is used for detecting, processing according to a pumping current signal of a pumping electrode and a reference induction potential signal of a reference electrode to obtain an advanced pumping oxygen signal, and sending the advanced pumping oxygen signal to the oxygen pumping module; the reference induced potential signal is generated by superposing potential difference generated by 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 pump oxygen module is used for being connected with the signal processing module and used for adjusting a main pump-pump potential difference between a main pump electrode and a pump electrode according to the received advanced pump oxygen signal so as to pump oxygen to a chamber. The oxygen pumping device for the nitrogen-oxygen sensor solves the problem that the concentration measurement of nitrogen oxides in the nitrogen-oxygen sensor in the prior art is not accurate.

Description

Nitrogen and oxygen sensor oxygen pumping device and nitrogen and oxygen sensor

Technical Field

The utility model relates to the field of automobile exhaust treatment, in particular to a nitrogen-oxygen sensor oxygen pumping device and a nitrogen-oxygen sensor.

Background

The current type nitrogen-oxygen sensor is made of a ceramic material based on an aluminum oxide and zirconia matrix (materials such as doped yttrium oxide and the like), and is widely applied to detection of nitrogen oxides in tail gas of diesel vehicles due to the advantages of high temperature resistance, corrosion resistance, long service life, sensitivity to gas and the like. The detection principle is that after the temperature exceeds 300 ℃, by applying voltage on two sides of a zirconia matrix, zirconia can conduct electricity through the migration of oxygen ions, so that current is formed. In the diesel vehicle emission process, tail gas contains gas such as oxynitride, oxygen, hydrocarbon in the gas that awaits measuring promptly, behind a cavity in the oxynitride sensor, oxygen in the gas that awaits measuring can be pumped outside the oxynitride sensor under voltage and high temperature effect, remaining await measuring gas enters into two cavities in the oxynitride sensor, oxynitride decomposes into oxygen and nitrogen gas under the catalyst effect, decomposed oxygen can be pumped outside the oxynitride sensor again, the concentration of oxynitride can be calculated through the oxygen ion electric current that produces when the oxygen of decomposition is pumped out.

In the prior art, the oxygen response speed of the first chamber pump is low, so that excessive oxygen enters the two chambers, the oxygen capacity of the two chambers exceeds the oxygen pumping capacity range of the two chambers, the two chambers pump oxygen cannot maintain balance, the oxygen concentration of the oxynitride measurement position is excessive, the oxygen ion current measured at the measurement position is larger than that of the actual oxynitride decomposition, and the concentration measurement value of oxynitride is not a true value.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects in the prior art, the utility model provides an oxygen pumping device of a nitrogen-oxygen sensor and the nitrogen-oxygen sensor, which can solve the technical problem that the concentration of oxynitride in the nitrogen-oxygen sensor in the prior art is not accurately measured.

The utility model provides a nitrogen-oxygen sensor oxygen pumping device, which comprises a signal processing module and an oxygen pumping module, wherein,

the signal processing module is used for detecting a pump current signal of a pump electrode in the nitrogen-oxygen sensor and a reference induction potential signal of a reference electrode, processing the pump current signal and the reference induction potential signal to obtain an advanced pump oxygen signal, and sending the advanced pump oxygen signal to the pump oxygen module; the reference induction potential signal is generated by superposing a potential difference generated by an oxygen concentration difference between a 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 pumping oxygen module is used for being connected with the signal processing module and used for adjusting a main pump-pump potential difference between the main pump electrode and the pump electrode according to the received advanced pumping oxygen signal so as to adjust oxygen ion current of the pump electrode and pump oxygen to a chamber in the nitrogen-oxygen sensor.

Optionally, the apparatus further includes a control module, configured to be connected to the signal processing module, and configured to detect two pump reference potential difference signals between two pump electrodes in the nitrogen oxygen sensor and the reference electrode, and two pump current signals of the two pump electrodes, process the two pump reference potential difference signals and the two pump current signals to obtain a signal to be modulated according to the two pump reference potential difference signals, and send the signal to be modulated to the signal processing module; wherein the two-pump reference potential difference signal is generated by the difference of oxygen concentration between the two pump electrodes and the reference electrode;

the signal processing module is further configured to process the pump current signal, the reference induced potential signal and the received signal to be adjusted to obtain a feedback pump oxygen signal, and send the feedback pump oxygen signal to the pump oxygen module;

the oxygen pumping module is further configured to adjust a main pump-pump potential difference between the main pump electrode and the pump electrode according to the received feedback pumping oxygen signal, so as to adjust an oxygen ion current of the pump electrode, so as to pump oxygen to the chamber until a current value of the two pump current signals reaches a preset current value and a potential difference of the two pump reference potential difference signals reaches a preset potential difference.

Optionally, the signal processing module includes a first processing module, configured to detect and process the pump current signal; the first processing module comprises a first operational amplifier, a first resistor, a first capacitor and a second resistor;

the inverting input end of the first operational amplifier is used for receiving the pump current signal and is respectively connected with one end of the first resistor and one end of the first capacitor;

the other end of the first resistor is respectively connected with 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 with one end of the second resistor, and the other end of the second resistor is connected with the positive-phase input end of the first operational amplifier;

the power supply end of the first operational amplifier is connected with a first preset voltage, and the grounding end of the first operational amplifier is grounded.

Optionally, the signal processing module further comprises a second processing module, configured to detect and process the reference sensing potential signal; the second processing module comprises a second operational amplifier, a third resistor, a fourth resistor, a second capacitor and a fifth resistor;

the positive phase input end of the second operational amplifier is used for receiving the reference induced potential signal, and the negative phase input end of the second operational amplifier is respectively connected with 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 connected with the other end of the second capacitor and one end of the fifth resistor respectively, and the other end of the fifth resistor is connected with the output end of the second operational amplifier;

the power supply end of the second operational amplifier is connected with a second preset voltage, and the grounding end of the second operational amplifier is grounded.

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

the negative electrode of the clamping diode is respectively connected with 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 with 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 negative electrode of the clamping diode is also connected with one end of the ninth resistor, and the other end of the ninth resistor is connected with the positive-phase input end of the first operational amplifier.

Optionally, the second processing module further includes a voltage divider, a first input end of the voltage divider is connected to one end of the sixth resistor, a second input end of the voltage divider is connected to the other end of the seventh resistor, a first output end of the voltage divider is connected to the two pump electrodes, and a second output end of the voltage divider is connected to the measurement electrode.

Optionally, the apparatus further includes a tenth resistor, an eleventh resistor, a third capacitor, and a fourth capacitor;

the control module is further configured to connect one end of a tenth resistor, the other end of the tenth resistor is connected to one end of the eleventh resistor and one end of the third capacitor, respectively, the other end of the third capacitor is grounded, the other end of the eleventh resistor is connected to one end of the fourth capacitor and the positive-phase input terminal of the first operational amplifier, respectively, and the other end of the fourth capacitor is grounded.

In a second aspect, the utility model provides a nitrogen-oxygen sensor, which comprises a core body and the oxygen pumping device, wherein the oxygen pumping device is used for pumping oxygen into a cavity in the core body.

The utility model discloses a nitrogen-oxygen sensor oxygen pumping device, which comprises a signal processing module and an oxygen pumping module, wherein the signal processing module is used for detecting and processing a pumping current signal and a reference induced potential signal, and sending an advanced oxygen pumping signal obtained by processing; the pump oxygen module is used for connecting the signal processing module, a potential difference between the main pump electrode and a pump electrode is adjusted according to the received advanced pump oxygen signal, so as to pump oxygen to a chamber, the device can change the potential difference between the main pump electrode and a pump electrode by detecting the reference induced potential signal and a pump current signal before the gas to be measured enters two chambers, so as to pump oxygen to a chamber, thereby reducing the oxygen concentration of the gas to be measured of a chamber in advance, avoiding the gas to be measured with the increased oxygen concentration from diffusing into two chambers, avoiding exceeding the oxygen range of the two chambers, keeping the two chambers in balance, and ensuring that the concentration of the nitrogen oxide measured by the measuring electrode is more accurate.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is also possible for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a core body of a nitrogen-oxygen sensor provided by the utility model;

FIG. 2 is a schematic structural diagram of a NOx sensor oxygen pumping apparatus according to an embodiment of the present invention;

fig. 3 is a circuit diagram of a first processing module of a signal processing module in an oxygen pumping apparatus for a nitrogen oxygen sensor according to a second embodiment of the present invention;

FIG. 4 is another circuit diagram of a first processing module of the signal processing module of the oxygen pumping device for a NOx sensor according to the present invention;

fig. 5 is a circuit diagram of a second processing module of the signal processing module in the oxygen pumping device for a nitrogen oxygen sensor according to the third embodiment of the present invention;

fig. 6 is a schematic diagram illustrating the operation of a control module in the oxygen pumping apparatus for a nitrogen oxygen sensor according to the fourth embodiment of the present invention;

Fig. 7 is a graph showing the relationship between the electrical parameter and the oxygen concentration in the chamber of the oxygen and nitrogen sensor oxygen pumping device according to the fifth embodiment of the present invention.

Detailed Description

In order to make the objects, features and advantages of the present invention more obvious and understandable, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments, which can be obtained by those skilled in the art without making any creative effort based on the embodiments of the present invention, belong to the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a core body of a nitrogen oxygen sensor provided in the present invention.

As shown in figure 1, the core body of the nitrogen-oxygen sensor comprises a cavity, two cavities and a reference cavity, a main pump electrode, a pump electrode, two pump electrodes, a measuring electrode, a reference electrode and a heating electrode are arranged in the core body, the pump electrode is arranged in the cavity, the two pump electrodes and the measuring electrode are arranged in the cavities, the reference electrode is communicated with the reference cavity, and the reference cavity is communicated with the outside air. The diffusion barrier is arranged in front of the first chamber, the isolation barrier is arranged between the first chamber and the second chamber, and the diffusion barrier and the isolation barrier are made of porous alumina, so that gas to be detected enters the first chamber and the second chamber at a certain speed.

Different preset voltages are respectively connected to the electrodes, 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 is constant and greater than the values of V1, V2 and V3, and the value of V4 may be greater than, equal to or less than the value of V0. The oxygen ion current I1 of one pump electrode, the oxygen ion current I2 of two pump electrodes and the oxygen ion current I3 of the measuring electrode all flow out of the main pump electrode, so that oxygen ions are gathered on the main pump electrode to form oxygen to be pumped out.

In the prior art, current is applied to the heating electrode to heat the core body, and the core body becomes a conductor when the temperature of the core body is 600 to 850 ℃. The voltage is applied between the electrodes in the zirconia matrix, the zirconia can conduct electricity through the migration of oxygen ions, so that oxygen ion current is formed, namely, oxygen in the gas to be measured in one cavity and two cavities can be pumped out of the core body in the form of the oxygen ion current, so that the gas to be measured entering the two cavities almost does not contain oxygen and only contains nitrogen oxide, the nitrogen oxide is decomposed into nitrogen and oxygen through catalytic reduction reaction of a 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 the nitrogen oxide in the gas to be measured can be calculated according to the amount of the oxygen pumped out of the measuring electrode. The oxygen concentration and the nitrogen oxide concentration in the gas to be measured in the chamber and the two chambers can be calculated by measuring the oxygen ion current of each electrode. Oxygen in the gas to be measured in a chamber cannot be completely pumped out, otherwise nitrogen oxide is decomposed into nitrogen and oxygen in a chamber.

In the prior art, a voltage is applied to a pump electrode to pump out oxygen in a gas to be tested, the oxygen content is controlled to be 3-5 million percent by volume fraction (nitrogen oxides are prevented from generating reduction reaction in a chamber), after the gas to be tested enters two chambers, the two pump electrodes continuously pump out the oxygen entering the chamber, so that the oxygen content in the two chambers approaches to 10-3 million percent by volume fraction, and the influence of the oxygen in the gas to be tested on a test result caused by the fact that the oxygen enters a measuring electrode is avoided.

In the prior art, whether the oxygen concentration of the gas to be measured entering the two chambers changes is judged through the oxygen ion current I2 of the two pump electrodes, so that the main pump-pump potential difference V01 between the main pump electrode and the pump electrode in the one chamber is controlled to pump oxygen, and the oxygen concentration of the gas to be measured entering the two chambers is further adjusted, however, before the oxygen ion current I2 of the two pump electrodes is detected to change, the oxygen concentration of the gas to be measured entering the two chambers changes, so that the oxygen ion current I3 of the measuring electrode in the two chambers changes, and the calculated concentration of the oxynitride in the gas to be measured is inaccurate. Therefore, the prior art has the technical defect that the change of the oxygen concentration induced by the two cavities lags behind.

It should be noted that, the larger the oxygen concentration is, the larger the oxygen ion current is, the higher the oxygen potential difference between the two electrodes is, and the larger the oxygen ion current is, the larger the oxygen concentration is, and the larger the potential difference is.

The greater (or smaller) the difference in oxygen concentration between the other electrode (e.g., main pump electrode, one pump electrode, two pump electrodes, measurement electrode) and the reference electrode, the smaller (or larger) the potential difference between the other electrode and the reference electrode, according to nernst's principle. Only a potential difference exists between the other electrode and the reference electrode, and no current exists. The reference electrode is in communication with air, which has an oxygen concentration of between 19.5% and 23.5%, and in some embodiments of the present application, the oxygen concentration in the reference chamber is always 20.9%, while the oxygen concentration at the other electrodes is typically less than the oxygen concentration in air.

It should be noted that the tail gas, i.e., the gas to be measured, gradually enters the cavity of the core body of the nitrogen-oxygen sensor step by step in a diffusion manner. The gas to be measured is introduced into the nitrogen-oxygen sensor core body and is divided into three stages according to the time sequence. Stage 1: the gas to be measured diffuses on the surface of the head of the core body; and (2) stage: the gas to be measured enters a chamber through an isolation barrier in front of the chamber; and (3) stage: and the gas to be detected passes through the diffusion barrier behind the first chamber and enters the two chambers.

When the oxygen concentration of the gas to be measured changes, in the first stage, oxygen in the gas to be measured first diffuses on the substrate near the main pump electrode, and according to the nernst principle, the voltage V04 between the main pump electrode and the reference electrode changes in this stage, and since the potential V0 of the main pump electrode does not change, the potential V4 of the reference electrode changes in this stage. In the second stage, after the gas to be measured is diffused into a chamber, the oxygen concentration of the chamber is changed, so that the oxygen ion current I1 of a pump electrode is changed at this stage. In the third stage, after the gas to be measured enters the two chambers, the oxygen concentration in the two chambers changes, and in this stage, the oxygen ion current I2 of the two pump electrodes changes, and of course, the voltage V24 between the two pump electrodes and the reference electrode also changes according to the nernst principle.

Referring to fig. 2, fig. 2 is a schematic structural diagram of an oxygen pumping apparatus for a nitrogen oxygen sensor according to an embodiment of the present invention.

In a first aspect, the present invention provides a nox sensor oxygen pumping device, as shown in fig. 2, the device includes a signal processing module 1 and an oxygen pumping module 2, wherein,

the signal processing module 1 is used for detecting and processing a pumping current signal of a pumping electrode in the nitrogen-oxygen sensor and a reference induction potential signal of a reference electrode, and sending the processed advanced pumping oxygen signal to the pumping oxygen module 2. Wherein the potential V0 of the main pump electrode is a preset value, and the preset value is selected to be 2.0-2.5 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.

It should be noted that preset voltage is connected to both the main pump electrode and the reference electrode, and a potential difference exists between the main pump electrode and the reference electrode, but according to the nernst principle, when an oxygen concentration difference exists between the main pump electrode and the reference electrode, a potential difference is induced between the main pump electrode and the reference electrode, and since the potential V0 of the main pump electrode is unchanged, the induced potential difference is superposed on the reference electrode to form the potential V4 of the reference electrode, and the detected reference induced potential signal is a signal of the potential V4 of the reference electrode.

Preferably, in conjunction with fig. 1-2, the potential V0 of the primary pump electrode is constant and the potential V4 of the reference electrode changes according to nernst's principle when the difference in oxygen concentration between the primary pump electrode and the reference electrode changes. The oxygen concentration of the test gas entering a chamber changes, as does the oxygen ion current I1 of a pump electrode. Therefore, according to the above principle description, in the first stage and the second stage, the oxygen concentration of the gas to be measured changes, and the oxygen ion current I1 of a pump electrode and the potential V4 of the reference electrode change.

Accordingly, a pumping current signal is a signal of the oxygen ion current I1 of a pumping electrode, and a reference induced potential signal is a signal of the potential V4 of a reference electrode. By detecting the oxygen ion current I1 of a pump electrode and the potential V4 of a reference electrode, the oxygen concentration of the gas to be detected can be known to change, so that oxygen can be pumped into one chamber in advance, and the gas to be detected with the changed oxygen concentration is prevented from entering two chambers.

As shown in fig. 1 to fig. 2, the pump oxygen module 2 is configured to connect to the signal processing module 1, and is configured to adjust a main pump-pump potential difference V01 between a main pump electrode and a pump electrode according to the received early pump oxygen signal, so as to adjust an oxygen ion current I1 of the pump electrode, so as to pump oxygen to a chamber in the nox sensor.

In fact, the potential V0 of the main pumping electrode is constant, so that the potential difference V01 between the main pumping electrode and a pumping electrode can be changed by only adjusting the potential V1 of a pumping electrode, thereby changing the oxygen ion current I1 of a pumping electrode and changing the oxygen pumping rate of a chamber.

For example, when the oxygen concentration of the gas to be measured is increased and the gas to be measured diffuses on the substrate surface of the main pump electrode, oxygen is adsorbed on the main pump electrode due to the electromagnetic force of the potential V0 applied to the main pump electrode, the oxygen concentration at the main pump electrode is increased, according to the nernst principle, the potential difference between the main pump electrode and the reference electrode is decreased, while the potential V0 of the main pump electrode is not changed, and then the potential V4 of the reference electrode is decreased.

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

Because the gas to be detected is diffused on the surface of the substrate of the main pump electrode before being introduced into a chamber, the oxygen concentration of the gas to be detected can be known in advance to be changed through the detected changed potential V4 of the reference electrode, and the preparation is made for pumping oxygen in advance.

The gas to be measured continuously enters a chamber, the oxygen concentration is increased, the main pump-pump potential difference V01 between the main pump electrode and a pump electrode is unchanged, and then the oxygen ion current I1 of the pump electrode is increased.

At this time, the oxygen concentration of the gas to be measured is increased, so that the oxygen ion current I1 of a pump electrode is increased and the potential V4 of the reference electrode is decreased, and the oxygen ion current I1 of a pump electrode and the potential V4 of the reference electrode are detected, that is, the potential V1 of the pump electrode is decreased, so that the main pump-pump potential difference V01 between the main pump electrode and the pump electrode is increased, so that the oxygen ion current I1 of the pump electrode is increased, oxygen pumping of a chamber is accelerated, the oxygen concentration of the gas to be measured in the chamber is decreased, and the gas to be measured with the increased oxygen concentration is prevented from being diffused into the two chambers.

The utility model discloses a nitrogen-oxygen sensor oxygen pumping device, which comprises a signal processing module and an oxygen pumping module, wherein the signal processing module is used for detecting and processing a pumping current signal and a reference induced potential signal and sending an advanced oxygen pumping signal obtained by processing; the pump oxygen module is used for connecting the signal processing module, a potential difference between the main pump electrode and a pump electrode is adjusted according to the received advanced pump oxygen signal, so as to pump oxygen to a chamber, the device can change the potential difference between the main pump electrode and a pump electrode by detecting the reference induced potential signal and a pump current signal before the gas to be measured enters two chambers, so as to pump oxygen to a chamber, thereby reducing the oxygen concentration of the gas to be measured of a chamber in advance, avoiding the gas to be measured with the increased oxygen concentration from diffusing into two chambers, avoiding exceeding the oxygen range of the two chambers, keeping the two chambers in balance, and ensuring that the concentration of the nitrogen oxide measured by the measuring electrode is more accurate.

Further, as shown in fig. 2, the apparatus further includes a control module 3, which is connected to the signal processing module 1, and configured to detect the two-pump reference potential difference signal between the two pump electrodes and the reference electrode and the two-pump current signal of the two pump electrodes, process the two-pump reference potential difference signal and the two-pump current signal to obtain a signal to be adjusted, and send the signal to be adjusted 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. The two-pump current signal is the signal of the oxygen ion current I2 of the two-pump electrode.

The Control module 3 may be a single chip microcomputer, an FPGA (Field Programmable gate array), a PLC (Programmable Logic Controller), an ECU (Electronic Control Unit), a DCU (Drive Control Unit), and the like, and preferably, in this embodiment, the Control module 3 may be an ECU or a DCU.

The signal processing module 1 is further configured to process the pump current signal, the reference induced potential signal and the received signal to be adjusted to obtain a feedback pump oxygen signal, and send the feedback pump oxygen signal. The signal to be modulated is a voltage signal.

The pumping oxygen module 2 is further configured to adjust a main pump-pump potential difference V01 between the main pump electrode and the first pump electrode according to the received feedback pumping oxygen signal, so as to pump oxygen to the first chamber until a current value of the two-pump current signal reaches a preset current value and a potential difference of the two-pump reference potential difference signal reaches a preset potential difference.

Preferably, the reference potential difference V24 of the two pumps reaches a preset potential difference, the preset potential difference is a constant value between 410 mv and 450 mv, the current value of the oxygen ion current I2 of the two pump electrodes reaches a preset current value, and the preset current value is a constant value between 5 microamperes and 9 microamperes.

Further, the apparatus further comprises a power supply module (not shown in fig. 2) for supplying power to the signal processing module 1. Preferably, the power module is further configured to supply power to the control module 3.

Further, the control module 3 outputs a signal to be modulated in a form of a PWM (Pulse width modulation) wave.

Referring to fig. 3, fig. 3 is a circuit diagram of a first processing module of a signal processing module in an oxygen pumping apparatus for a nitrogen oxygen sensor according to a second embodiment of the present invention.

Further, as shown in fig. 3, 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.

The inverting input terminal of the first operational amplifier a1 is used for receiving a pump current signal, and is further connected to one end of the first resistor R1 and one end of the first capacitor C1, respectively.

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.

The output terminal of the first operational amplifier a1 is further connected to one terminal of a second resistor R2, and the other terminal of the second resistor R2, i.e., the terminal a in fig. 3, is connected to the non-inverting input terminal of the first operational amplifier a1, for superimposing the potential output converted from a pump current signal to the potential V1 of a pump electrode.

The power supply terminal of the first operational amplifier a1 is connected to a first predetermined voltage, and the ground terminal thereof is grounded. Wherein the first preset voltage is 3-30 volts.

Referring to fig. 4, fig. 4 is another circuit diagram of a first processing module of a signal processing module in the oxygen pumping device for a nox sensor according to the present invention.

As shown in fig. 4, compared to fig. 3, the first processing module of the prior art further includes a third operational amplifier a3 and a twelfth resistor R12.

The non-inverting input terminal of the third operational amplifier A3 is connected to the output terminal of the first operational amplifier a1 and one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is grounded.

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.

The power supply terminal of the third operational amplifier a3 is connected to a third predetermined voltage, and the ground terminal thereof is grounded. Wherein the third preset voltage is 3-30 volts.

The third operational amplifier a3 and the twelfth resistor R12 in the prior art shown in fig. 4 function to convert a current input to a non-inverting input terminal thereof into a potential output. In the embodiment of the present application shown in fig. 3, the third operational amplifier A3 and the twelfth resistor R12 are removed, and the current output from the output terminal of the first operational amplifier a1 flows through the second resistor R2, and is converted into a potential and directly output to the non-inverting input terminal of the first operational amplifier a 1. Compared with the prior art in fig. 4, the first processing module provided by the embodiment of the present application in fig. 3 has a simple structure and a low cost, and because one operational amplifier and one resistor are removed, an error amplification rate caused by a complex circuit structure is reduced, so that the electric potential output by the first processing module is more stable.

It should be noted that, in the prior art, at least 2 operational amplifiers are usually required to convert and feed back the oxygen ion current I1 of a pump electrode to the potential V1 of a pump electrode. The oxygen ion current I1 of a pump electrode can be converted and fed back to the potential V1 of the pump electrode by only one operational amplifier, so that noise interference caused by excessive operational amplifiers is reduced, and the response speed of the pump oxygen is improved.

Referring to fig. 5, fig. 5 is a circuit diagram of a second processing module of the signal processing module in the oxygen pumping device of the nitroxide sensor according to the third embodiment of the present invention.

Further, as shown in fig. 5, the signal processing module 1 further includes a second processing module for detecting and processing the reference sensing potential signal. The second processing module comprises 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 by a factor of 1-2 and to perform RC (resistance Capacitance) filtering.

The non-inverting input terminal of the second operational amplifier a2 is used for receiving the reference sensing potential signal, and the inverting input terminal thereof is connected to one terminal of the third resistor R3, one terminal of the fourth resistor R4 and one terminal of the second capacitor C2 respectively.

The other end of the third resistor R3 is grounded, the other end of the fourth resistor R4 is connected to the other end of the second capacitor C2 and one end of the fifth resistor R5, respectively, and the other end of the fifth resistor R5 is connected to the output end of the second operational amplifier a 2.

The power supply terminal of the second operational amplifier a2 is connected to the second predetermined voltage, and the ground terminal thereof is grounded. Wherein the second preset voltage is 3-30 volts.

Further, as shown in fig. 5, 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 added device of the second processing module here is to clamp the potential V4 of the reference electrode after amplification and filtering.

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

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 terminal of the second operational amplifier a 2.

The cathode of the clamping diode D is also connected to one end of a ninth resistor R9, and the other end of the ninth resistor R9, i.e., the end B in fig. 4, is connected to the non-inverting input terminal of the first operational amplifier a1, for superimposing the potential output converted from the reference induced potential signal to the potential V1 of one pump electrode.

Further, as shown in fig. 5, the second process module further includes a voltage dividing circuit for dividing the potential V4 of the clamped reference electrode. The first input end of the voltage division circuit is connected with one end of a sixth resistor R6, the second input end of the voltage division circuit is connected with the other end of a seventh resistor R7, the first output end, namely the D end of the voltage division circuit, is connected with two pump electrodes to output the potential V2 of the two pump electrodes, the second output end, namely the E end of the voltage division circuit, is connected with a measuring electrode to output the potential V3 of the measuring electrode.

As shown in fig. 6, fig. 6 is a schematic diagram illustrating operation of a control module in an oxygen pumping apparatus for a nitrogen oxygen sensor according to a fourth embodiment of the present invention.

Further, as shown in fig. 6, the apparatus further includes a tenth resistor R10, an eleventh resistor R11, a third capacitor C3, and a fourth capacitor C4.

The control module 3 is further configured to connect one end of a tenth resistor R10, the other end of the tenth resistor R10 is connected to one end of an eleventh resistor R11 and one end of a third capacitor C3, respectively, the other end of the third capacitor C3 is grounded, the other end of the eleventh resistor R11 is connected to one end of a fourth capacitor C4 and the non-inverting input terminal of the first operational amplifier a1, and the other end of the fourth capacitor C4 is grounded.

The control module 3 is configured to detect a two-pump current signal and a two-pump reference potential difference signal, and process the two-pump current signal and the two-pump reference potential difference signal to obtain a signal to be adjusted, where it should be noted that the signal to be adjusted output by the control module 3 is a PWM square wave current signal, and 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 a potential V1 superimposed on a pump electrode.

It should be noted that, as shown in fig. 3, fig. 5 and fig. 6, the terminal a in fig. 3, the terminal B in fig. 5 and the terminal C in fig. 6 are all connected to the non-inverting input terminal of the first operational amplifier a1 in fig. 3, and are respectively used for converting a pump current signal into a potential, converting a reference induced potential signal into a potential, and converting two pump current signals and two pump reference potential difference signals into signals to be adjusted and filtering the obtained potentials, which are all superimposed on the potential V1 of one pump electrode. Therefore, when the detected first pump current signal, the reference induced potential signal, the second pump current signal and the second pump reference potential difference signal are changed, the potential difference between the main pump electrode and the first pump electrode can be changed by changing the potential V1 formed by superposing the potential signals on the first pump potential, so that oxygen is pumped into one chamber, the oxygen concentration of the gas to be measured in the one chamber is reduced in advance, the gas to be measured with the increased oxygen concentration is prevented from diffusing into the two chambers, the oxygen range of the two chambers is prevented from being exceeded, the oxygen can be pumped into the two chambers in a balanced manner, and the concentration of nitrogen oxide measured by the measuring electrode is more accurate.

In the embodiment of the utility model, the pump oxygen in the first chamber and the pump oxygen in the second chamber are balanced by controlling the potential V1 and the oxygen ion current I1 of the first pump electrode, 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, so that the measurement of the concentration of the nitrogen oxide in the gas to be measured is completed.

With the fact that gas to be detected sequentially enters a chamber and two chambers through diffusion, dynamic balance of oxygen in the chamber is broken, a pumping oxygen channel in the chamber has only two paths, one path is that voltage is applied to a pumping electrode of the chamber, the pumping oxygen capacity of the chamber is changed by changing a main pump-pump potential difference V01 between a main pump electrode and the pumping electrode, and the larger the main pump-pump potential difference V01 between the main pump electrode and the pumping electrode is, the stronger the pumping oxygen capacity is (namely, the larger the oxygen ion current I1 of the pumping electrode is). The other way is to apply voltage to two pump electrodes of two chambers, and change the oxygen pumping capacity by changing the voltage of a main pump and the two pump electrodes, and because the oxygen pumping capacity of the two chambers is limited, the change of the oxygen concentration is mainly completed by the oxygen pumping of one chamber.

Referring to fig. 7, fig. 7 is a graph illustrating a relationship between an electrical parameter and an oxygen concentration in a chamber of an oxygen pumping device of a nox sensor according to a fifth embodiment of the present invention.

For example, as shown in fig. 7, the change of the oxygen ion current I1 of a pump electrode and the change of the reference induced potential V04 between the main pump electrode and the reference electrode, which are caused by the change of the oxygen concentration in the gas to be measured, are processed by signal operation to obtain an advanced pumping oxygen signal, which is directly input to the pump electrode without feedback adjustment, the main pump-pump potential difference V01 between the main pump electrode and the pump electrode is adjusted in advance, so that the oxygen concentration of the gas to be measured entering the two chambers through the one chamber is maintained within the range of the pumping oxygen capacity of the two chambers, the control module 3 calculates the voltage to be adjusted by measuring the oxygen ion current I2 of the two pump electrodes of the two chambers, and then, together with the oxygen ion current I1 of the pump electrode and the reference induced potential V04 between the main pump electrode and the reference electrode, the voltage is processed by signals and then fed back to the one pump electrode, to fine-tune the potential V1 of the one pump electrode, namely, the main pump-to-pump potential difference V01 between the main pump electrode and a pump electrode is finely adjusted so that the oxygen concentration in the two chambers is in a dynamic equilibrium.

In one embodiment of the present invention, in order to maintain the oxygen balance of the two chambers, 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 need to be maintained at constant values by a control method. In some embodiments of the present application, as shown in FIG. 6, the potential difference V24 between the two pump reference electrodes is constant between 410 mV and 450 mV, and the oxygen ion current I2 between 5 microamperes and 9 microamperes between the two pump electrodes is constant.

In circuit design, the main pump electrode to ground voltage V0 is fixed at a constant value between 2V and 2.5V, the change of the reference electrode potential in the first stage diffusion reflects the change of the oxygen concentration in the gas to be measured, and in fig. 7, the potential difference V04 of the main pump electrode to the reference electrode and the potential difference V01 of the main pump electrode to a pump electrode are in positive correlation, so the potential V4 of the reference electrode and the potential V1 of the pump electrode are in positive correlation. In order to maintain the constant value of the two-pump reference potential difference V24 between 410 and 450 mV, a voltage stabilizing tube is used in circuit design, and the two-pump reference potential difference V24 is always clamped at a constant value between the two-pump reference potential difference V24 and the constant value.

The potential difference V24 between the voltage input of the two pump electrodes and the voltage input of the reference electrode is constant between 410 mv and 450 mv due to the amplification, clamping and voltage dividing effects of the second processing block of fig. 5, so that the change in the potential V2 of the two pump electrodes is automatically adjusted by the change in the potential V4 of the reference electrode without further intervention.

After the voltages in fig. 3 and 5 are superposed, the superposed voltages are input to a pump electrode as a pre-adjusted voltage, so that a main pump-pump potential difference V01 of a chamber pump oxygen is changed, thereby changing the pump oxygen capacity, and performing pre-adjustment on the oxygen concentration of a chamber, after the adjustment, the oxygen concentration entering the two chambers is within the adjustment capacity range, the oxygen ion current I2 of the two pump electrodes is measured and input to the control module 3, after the control module 3 is adjusted by PID (proportional Integral Differential), a voltage signal to be adjusted in a PWM waveform form is output, and after the two-stage RC filtering in fig. 6, the voltage signal is input to the a end in fig. 3 from the C end, the oxygen pump potential difference of the one chamber is finely adjusted, and the pump oxygen balance of the one chamber and the two chambers is maintained.

The utility model discloses a nitrogen-oxygen sensor oxygen pumping device, which comprises a signal processing module and an oxygen pumping module, wherein the signal processing module is used for detecting and processing a pumping current signal and a reference induced potential signal and sending an advanced oxygen pumping signal obtained by processing; the pump oxygen module is used for connecting the signal processing module, a potential difference for between main pump electrode and a pump electrode is adjusted according to received pump oxygen signal in advance, with to a cavity pump oxygen, this device can be before the gas that awaits measuring gets into two cavities, judge whether the oxygen concentration of the gas that awaits measuring changes through detecting reference induced potential signal and a pump current signal, if change, just change the potential difference between main pump electrode and a pump electrode and come to a cavity pump oxygen, thereby reduce the oxygen concentration of a cavity gas that awaits measuring in advance, avoid the gas that awaits measuring that oxygen concentration increases to diffuse in the cavity. The device can pump oxygen to one chamber in advance, avoid excessive oxygen from entering the two chambers and exceeding the oxygen pumping range of the two chambers, so that the two chambers can maintain the balance of the oxygen pumping, and the concentration of the nitrogen oxide measured by the measuring electrode is more accurate.

In a second aspect, the utility model provides a nitrogen-oxygen sensor, which comprises a core body and any one of the oxygen pumping devices, wherein the oxygen pumping device is used for pumping oxygen into a cavity in the core body.

The structure and the working principle of the oxygen pumping device are completely the same as those of the oxygen pumping device provided by the first aspect of the present invention, and are not described herein again.

The utility model discloses a nitrogen-oxygen sensor which comprises a core body and the oxygen pumping device, wherein the oxygen pumping device is used for pumping oxygen into a cavity in the core body. The oxygen pumping device comprises a signal processing module and an oxygen pumping module, wherein the signal processing module is used for detecting and processing a pumping current signal and a reference induced potential signal and sending an advanced oxygen pumping signal obtained by processing; the pump oxygen module is used for connecting the signal processing module, a potential difference for between main pump electrode and a pump electrode is adjusted according to received pump oxygen signal in advance, with to a cavity pump oxygen, this device can be before the gas that awaits measuring gets into two cavities, judge whether the oxygen concentration of the gas that awaits measuring changes through detecting reference induced potential signal and a pump current signal, if change, just change the potential difference between main pump electrode and a pump electrode and come to a cavity pump oxygen, thereby reduce the oxygen concentration of a cavity gas that awaits measuring in advance, avoid the gas that awaits measuring that oxygen concentration increases to diffuse in the cavity. The device can pump oxygen to one chamber in advance, avoid excessive oxygen from entering the two chambers and exceeding the oxygen pumping range of the two chambers, so that the two chambers can maintain the balance of the oxygen pumping, and the concentration of the nitrogen oxide measured by the measuring electrode is more accurate.

In the above embodiments, the description of each embodiment has its own weight, and for parts that are not described in detail in a certain embodiment, reference may be made to the description of other embodiments. The above description is provided for the oxygen pumping device of a nitroxide sensor and the nitroxide sensor, and persons skilled in the art may change the embodiments and application scope according to the idea of the embodiments of the present invention, and in summary, the content of the present specification should not be construed as limiting the present invention.

Claims

1. The oxygen pumping device of the nitrogen-oxygen sensor is characterized by comprising a signal processing module and an oxygen pumping module, wherein,

the signal processing module is used for detecting a pump current signal of a pump electrode in the nitrogen-oxygen sensor and a reference induction potential signal of a reference electrode, processing the pump current signal and the reference induction potential signal to obtain an advanced pump oxygen signal, and sending the advanced pump oxygen signal to the pump oxygen module; the reference induced potential signal is generated by superposing a potential difference generated by an oxygen concentration difference between a 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;

2. The device of claim 1, further comprising a control module, connected to the signal processing module, for detecting two pump reference potential difference signals between two pump electrodes in the oxynitride sensor and the reference electrode, two pump current signals of the two pump electrodes, processing the two pump reference potential difference signals and the two pump current signals to obtain a signal to be adjusted, and sending the signal to be adjusted to the signal processing module; wherein the two-pump reference potential difference signal is generated by the difference of oxygen concentration between the two pump electrodes and the reference electrode;

The oxygen pumping module is further configured to adjust a first pump potential difference of the main pump between the main pump electrode and the first pump electrode according to the received feedback pump oxygen signal, so as to adjust an oxygen ion current of the first pump electrode, so as to pump oxygen into the first chamber until a current value of the second pump current signal reaches a preset current value and a potential difference of the second pump reference potential difference signal reaches a preset potential difference.

3. The nitroxide sensor pumping oxygen device of claim 2, wherein the signal processing module comprises a first processing module for detecting and processing the pump current signal; the first processing module comprises a first operational amplifier, a first resistor, a first capacitor and a second resistor;

4. The nitroxide sensor pumping oxygen device of claim 3, wherein the signal processing module further comprises a second processing module for detecting and processing the reference sense potential signal; the second processing module comprises a second operational amplifier, a third resistor, a fourth resistor, a second capacitor and a fifth resistor;

the positive-phase input end of the second operational amplifier is used for receiving the reference induced potential signal, and the negative-phase input end of the second operational amplifier is respectively connected with one end of the third resistor, one end of the fourth resistor and one end of the second capacitor;

5. The nitroxide sensor pumping oxygen device of claim 4, wherein the second processing module further comprises a clamping diode, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor;

the negative electrode of the clamping diode is further connected with one end of the ninth resistor, and the other end of the ninth resistor is connected with the positive-phase input end of the first operational amplifier.

6. The NOx sensor pumping oxygen device of claim 5, wherein said second processing module further comprises a voltage divider circuit, a first input terminal of said voltage divider circuit is connected to one end of said sixth resistor, a second input terminal thereof is connected to the other end of said seventh resistor, a first output terminal thereof is connected to said two pump electrodes, and a second output terminal thereof is connected to said measuring electrode.

7. The nitroxide sensor pumping oxygen device of claim 6, further comprising a tenth resistor, an eleventh resistor, a third capacitor, and a fourth capacitor;

The control module is further configured to connect to one end of a tenth resistor, where the other end of the tenth resistor is connected to one end of the eleventh resistor and one end of the third capacitor, respectively, the other end of the third capacitor is grounded, the other end of the eleventh resistor is connected to one end of the fourth capacitor and the positive-phase input end of the first operational amplifier, respectively, and the other end of the fourth capacitor is grounded.

8. A nitroxide sensor comprising a core body and an oxygen pumping device as claimed in any of claims 1 to 7 for pumping oxygen to a chamber within the core body.