CN118130554A - Method and circuit for driving ammonia sensor - Google Patents
Method and circuit for driving ammonia sensor Download PDFInfo
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 307
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 137
- 238000000034 method Methods 0.000 title claims abstract description 22
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 54
- 239000007789 gas Substances 0.000 claims abstract description 32
- 239000000463 material Substances 0.000 claims abstract description 30
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000001301 oxygen Substances 0.000 claims abstract description 18
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 18
- 238000004891 communication Methods 0.000 claims description 45
- 238000012545 processing Methods 0.000 claims description 34
- 238000004364 calculation method Methods 0.000 claims description 30
- 238000006243 chemical reaction Methods 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 25
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 10
- 238000012544 monitoring process Methods 0.000 claims description 7
- 238000001914 filtration Methods 0.000 claims description 6
- 238000005457 optimization Methods 0.000 claims description 6
- 230000004044 response Effects 0.000 claims description 5
- 101001078093 Homo sapiens Reticulocalbin-1 Proteins 0.000 claims description 2
- 102100025335 Reticulocalbin-1 Human genes 0.000 claims description 2
- 238000001514 detection method Methods 0.000 abstract description 32
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 230000002708 enhancing effect Effects 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 9
- 238000013461 design Methods 0.000 description 8
- 230000006870 function Effects 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 230000003321 amplification Effects 0.000 description 5
- 230000007613 environmental effect Effects 0.000 description 5
- 238000003199 nucleic acid amplification method Methods 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 4
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 3
- 239000004202 carbamide Substances 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000008713 feedback mechanism Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000007405 data analysis Methods 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000002847 impedance measurement Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- DOTMOQHOJINYBL-UHFFFAOYSA-N molecular nitrogen;molecular oxygen Chemical compound N#N.O=O DOTMOQHOJINYBL-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000000041 tunable diode laser absorption spectroscopy Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
- G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor
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Abstract
The invention discloses a method for driving an ammonia sensor, which relates to the field of automobile electronic sensing detection, and comprises the following steps of: step 1, acquiring the actual temperature of an ammonia sensor; step 2, adjusting the actual temperature of the ammonia sensor to reach the set temperature of the ammonia sensor; step 3, acquiring voltage signals sent by gas sensitive materials for detecting the concentration of nitrogen oxides and oxygen on the ammonia sensor on the basis that the actual temperature of the ammonia sensor reaches the set temperature, and obtaining the concentration of the ammonia and the oxygen at present through operation treatment; the beneficial effects of the invention are as follows: according to the ammonia gas concentration detection method, the ammonia gas sensor is maintained at the set temperature, and ammonia gas concentration detection is performed, so that ammonia gas detection accuracy is ensured; the ammonia gas detector is relatively simple in structure, low in cost and capable of enhancing the possibility of wide application, simultaneously has sensitivity to ammonia gas with low concentration, and further improves the accuracy and practicability of ammonia gas detection.
Description
Technical Field
The invention relates to the field of automobile electronic sensing detection, in particular to a method and a circuit for driving an ammonia sensor.
Background
With the improvement of the social living standard, the rapid increase of the number of automobiles makes the traveling of people more convenient, however, the problem of environmental pollution is also aggravated. Nitrogen oxides (NO X) are a kind of harmful substances in automobile exhaust, the most common method for eliminating the nitrogen oxides is Selective Catalytic Reduction (SCR), nitrogen oxides (NO X) can be converted into nitrogen and water by spraying urea into a gas spraying pipe, a nitrogen-oxygen sensor is usually installed at the outlet of the SCR to detect the content of nitrogen oxides (NO X) after SCR, and the amount of urea sprayed is controlled to be adjusted correspondingly according to the detection result. Although SCR can effectively solve the emission of harmful nitrogen oxides, if urea is injected too much, excessive ammonia (NH 3) is generated, and ammonia is also a harmful gas, colorless, has strong pungent smell and is a toxic gas, so that the emission problem of ammonia is solved while eliminating nitrogen oxides, and the problem is to be solved first, so that an ammonia sensor is also installed in a vehicle equipped with an SCR system to detect the concentration of ammonia in real time.
Most of the existing measurement principles of various ammonia sensors rely on elements formed by gas-sensitive materials to react with ammonia gas to detect the concentration of ammonia gas, and the gas-sensitive materials generally have an optimal temperature to keep the activity and sensitivity of the materials, when the gas-sensitive materials are at the optimal temperature, the detection precision is the highest, but due to some influences caused by environmental or other factors, the temperature of the ammonia sensor may not be always maintained at the temperature at which the gas-sensitive materials are most active, so that the detection precision is affected, and improvement is needed.
Disclosure of Invention
The present invention is directed to a method and a circuit for driving an ammonia sensor, which solve the above-mentioned problems.
In order to achieve the above purpose, the present invention provides the following technical solutions:
A method for driving an ammonia gas sensor, comprising the steps of:
Step 1, acquiring the actual temperature of an ammonia sensor;
Step 2, adjusting the actual temperature of the ammonia sensor to reach the set temperature of the ammonia sensor;
And step 3, acquiring voltage signals sent by gas sensitive materials for detecting the concentration of nitrogen oxides and oxygen on the ammonia sensor on the basis that the actual temperature of the ammonia sensor reaches the set temperature, and obtaining the concentration of the ammonia and the oxygen at present through operation treatment.
As still further aspects of the invention: the step 1 specifically comprises the following steps:
Step 11, acquiring data of a thermosensitive zirconia internal resistance signal on an ammonia sensor to obtain resistance data of a thermosensitive material;
And step 12, acquiring the actual temperature of the ammonia sensor based on the one-to-one correspondence between the impedance of the thermosensitive material and the temperature.
A circuit for driving an ammonia gas sensor, comprising:
the wide linear amplifying circuit is used for receiving the voltage signal generated by the gas sensitive material on the ammonia sensor, amplifying the voltage signal in a wide linear range, obtaining an amplified signal and outputting the amplified signal to the signal conversion module;
The signal conversion module is used for converting the input amplified signal into a discrete digital signal and outputting the discrete digital signal to the data processing module;
The data processing module is used for receiving the digital signals, calculating the concentration of nitrogen oxides (NOX value) and the concentration of oxygen (O2 value) after filtering treatment, and finally obtaining the concentration of ammonia (NH 3 value);
The DFT integrated interface circuit is used for receiving the impedance analog signal output by the ammonia sensor and outputting the impedance analog signal to the alternating current impedance calculation module;
The alternating current impedance calculation module is used for analyzing the frequency response characteristic of the thermistor on the ammonia sensor, measuring voltage and current signals in the alternating current circuit, calculating the impedance value of the circuit by using a calculation formula (Z=R+jX) of the impedance, obtaining the impedance value of the thermistor on the ammonia sensor, and detecting the temperature of the ammonia sensor at the moment;
the temperature control module is used for receiving the actual temperature information of the ammonia sensor detected by the alternating current impedance calculation module and outputting a temperature control signal to the heating drive circuit according to the difference between the set temperature and the actual temperature;
The heating driving circuit is used for heating and driving the ammonia sensor according to the received temperature control signal so as to enable the actual temperature of the ammonia sensor to be matched with the set temperature;
the communication module is used for transmitting and receiving information;
The CAN communication module is used for constructing communication between the communication module and the control equipment;
The wide linear amplifying circuit is connected with the signal conversion module, the signal conversion module is connected with the data processing module and the communication module, the data processing module is connected with the communication module, the DFT integrated interface circuit is connected with the alternating current impedance calculation module, the alternating current impedance calculation module is connected with the temperature control module and the communication module, the temperature control module is connected with the communication module and the heating driving circuit, the communication module is connected with the CAN communication module, and the CAN communication module is connected with the control equipment.
As still further aspects of the invention: the circuit for driving the ammonia sensor further comprises a power module, wherein the power module is used for converting input voltage into 3.3V and 5V direct current and supplying the direct current to each module and each circuit.
As still further aspects of the invention: the control equipment comprises an engine control unit ECU, and is used for realizing comprehensive monitoring, control and optimization of the running state of the automobile by connecting various sensors and a data bus.
As still further aspects of the invention: the DFT integrated circuit further includes a compensation resistor Rcal for compensating the deviated impedance value to the standard impedance value.
As still further aspects of the invention: and an output temperature control signal output by the temperature control module is a PWM signal.
Compared with the prior art, the invention has the beneficial effects that: according to the invention, the ammonia concentration is detected by maintaining the temperature of the ammonia sensor within the set temperature (the optimal detection temperature range), so that the ammonia detection precision is ensured; the ammonia gas detector is relatively simple in structure, low in cost and capable of enhancing the possibility of wide application, simultaneously has sensitivity to ammonia gas with low concentration, and further improves the accuracy and practicability of ammonia gas detection.
Drawings
Fig. 1 is a schematic diagram of a circuit for driving an ammonia sensor.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making creative efforts based on the embodiments of the present invention are included in the protection scope of the present invention.
The existing independent ammonia sensor control system architecture has obvious defects, and most ammonia detection systems are integrated into a composite multi-gas sensor control system. The architecture of such a multi-gas sensor system is itself relatively complex, its structural complexity increases the difficulty of operation and maintenance, and the cost of the system is relatively high. In addition, mutual interference may occur between different gases, wherein the detection result of one gas may be affected by other gases, further reducing the reliability of the system. Such a multiple gas sensor control system is not the most desirable option for the detection of ammonia content in motor vehicle exhaust gases. The detection of ammonia content in motor vehicle exhaust is critical to environmental monitoring and emission control, and therefore a more accurate, simple and focused control system is needed. The existing system structure leads the ammonia gas detection to be interfered by multiple gases, reduces the detection accuracy, and increases the operation and maintenance difficulties due to complex system. Therefore, there is an urgent need to design a more focused and efficient independent ammonia sensor control system architecture to solve the problems of the existing multi-gas sensor system and improve the reliability and accuracy of ammonia detection.
In the prior art, cheng Junna (Cheng Junna, yang Ling, hao Xin, etc. design of STM 32-based ammonia gas detection system [ J ]. Technological information, 2021,19 (07): 60-63.DOI:10.16661/J. Cnki.1672-3791.2103-5042-5972), et al, proposed using a TDLAS-based gas detection module, designing an ammonia gas detection system having a response time of at most 32 s, which can realize detection of minute amounts of ammonia gas, due to the use of an optical principle sensor, which is relatively high in cost and requires specialized operation, installation and maintenance.
In a NOx sensor control system (CN 201510942731.2[ P ]. 2015.12.16), a control system architecture for NOx sensors is provided. Since the NOX sensor is also constructed of a heat sensitive material, it is required to achieve the highest detection accuracy at a specific temperature. The NOX sensor sends a voltage signal value to a NOX sensor control system, and detection of NOX concentration and control of NOX sensor temperature are achieved through signal conversion and data processing and the addition of control algorithms.
Cheng Junna et al propose an STM 32-based ammonia sensor control system that focuses on the control architecture of an optical ammonia sensor. The system utilizes the optical principle to detect, and estimates the concentration of ammonia by measuring the attenuation degree of light after passing through ammonia medium. In contrast, an nox sensor control system detects ammonia based on a physical temperature change of the semiconductor material. The optical ammonia sensor control system has the advantage of a highly accurate measurement principle, and the ammonia concentration is accurately monitored through the optical element. However, this is associated with higher costs, since such systems require the use of precision optical elements and specialized optical measuring equipment. In contrast, a NOx sensor control system employs relatively low cost semiconductor materials and conventional electronic measurement equipment. Although its detection principle is based on temperature variations of the semiconductor material, its cost-effective and easy-to-maintain properties make it more attractive in practical applications. Overall, there is a tradeoff between cost and performance for both ammonia sensor control systems. The optical ammonia sensor control system focuses on high accuracy detection, while a nitrogen oxide sensor control system focuses on economy and ease of use. Both have corresponding defects, so a method and a system for driving an ammonia sensor with high detection precision and low cost are needed.
Referring to fig. 1, a method for driving an ammonia sensor includes the steps of:
Step 1, acquiring the actual temperature of an ammonia sensor;
Step 2, adjusting the actual temperature of the ammonia sensor to reach the set temperature of the ammonia sensor;
And step 3, acquiring voltage signals sent by gas sensitive materials for detecting the concentration of nitrogen oxides and oxygen on the ammonia sensor on the basis that the actual temperature of the ammonia sensor reaches the set temperature, and obtaining the concentration of the ammonia and the oxygen at present through operation treatment.
In this embodiment: referring to fig. 1, step 1 specifically includes:
Step 11, acquiring data of a thermosensitive zirconia internal resistance signal on an ammonia sensor to obtain resistance data of a thermosensitive material;
And step 12, acquiring the actual temperature of the ammonia sensor based on the one-to-one correspondence between the impedance of the thermosensitive material and the temperature.
The DFT integrated interface circuit 4 is connected with the ammonia sensor, data acquisition is carried out on the thermosensitive zirconia internal resistance impedance signal on the ammonia sensor, the acquired impedance signals are transmitted to the alternating current impedance calculation module 5 of the microprocessor MCU for corresponding impedance calculation, then the temperature of the sensor at the moment can be judged by obtaining the impedance value due to the one-to-one correspondence between the impedance of the thermosensitive material and the temperature, and then the digital signal is transmitted to the temperature control module 7, the temperature control module 7 adds a certain control algorithm to control the temperature of the sensor in an optimal detection temperature range, the output high-level duty ratio is changed by utilizing the PWM principle, the temperature control of the ammonia sensor is realized, the sensor is kept in a state with the best sensitivity, and therefore the detection precision can be effectively ensured. Meanwhile, the ammonia gas sensor at the optimal temperature receives voltage signals sent by the gas sensitive material on the ammonia gas sensor for detecting the concentration of nitrogen oxides and oxygen through the allowance linear amplifying circuit 1, converts analog signals into digital signals through the transfer signal conversion module 2, sends the digital signals to the data processing module 3, performs operation processing by utilizing principles such as a Nernst equation to obtain the concentration of the ammonia gas and the oxygen gas at present, and sends the digital signals of the concentration information to the engine control unit ECU12 in a CAN communication mode to provide information for the subsequent control of the emission of the ammonia gas.
In this embodiment: referring to fig. 1, a circuit for driving an ammonia gas sensor includes:
The wide linear amplifying circuit 1 is used for receiving a voltage signal generated by the gas sensitive material on the ammonia sensor, amplifying the voltage signal in a wide linear range, acquiring an amplified signal and outputting the amplified signal to the signal conversion module 2; the allowance linear amplification circuit 1 is an amplification circuit having a large linear operation range (i.e., allowance). In the ammonia sensor control system, the main function of the system is to receive the voltage signal generated by the gas sensitive material on the ammonia sensor and amplify the voltage signal within a wide linear range. Since the voltage signal generated by the gas sensitive material may have different magnitudes under different operating conditions, the use of the spacious linear amplification circuit 1 helps to ensure that accurate and reliable amplification results can be obtained under various operating conditions without distortion or saturation. Such a circuit design helps to improve the adaptability of the system to different ammonia concentration variations, thereby enhancing the stability and reliability of the ammonia sensor control system. The key role of the allowance linear amplification circuit 1 in this scenario is to receive two key voltage signals from the ammonia sensor: one is a voltage signal regarding the nitrogen concentration, and the other is a voltage signal regarding the oxygen concentration. Through the module, the two voltage signals are amplified, so that the problem that the output signal of the ammonia sensor is weak and the MCU input requirement of the singlechip is difficult to directly meet is solved.
The signal conversion module 2 is used for converting the input amplified signal into a discrete digital signal and outputting the discrete digital signal to the data processing module 3; the main task of the signal conversion module 2 is to implement the conversion of analog signals into digital signals. In an ammonia sensor control system, the input of this module is the Nernst voltage signal for the gas sensitive material to detect nitrogen and oxygen, while the output is the continuous analog signal converted to a discrete digital signal by an analog-to-digital converter (ADC). This conversion process is critical because the digital signal is easier to process and transmit and is suitable for subsequent data analysis and processing steps. The converted digital signals are then transmitted to a data processing module 3, which performs operation processing by using the principles of the nernst equation and the like, so as to obtain concentration information of ammonia and oxygen. The design and performance of the signal conversion module 2 directly affects the sensitivity and accuracy of the system to gas concentration variations. Thus, a reasonable and efficient signal conversion module 2 is a key component in an ammonia sensor control system.
The data processing module 3 is used for receiving the digital signals, calculating the concentration of nitrogen oxides (NOX value) and the concentration of oxygen (O2 value) after filtering treatment, and finally obtaining the concentration of ammonia (NH 3 value); the primary task is to receive and process the digital signals converted by the signal conversion module. The module has a plurality of key functions, including accurate data acquisition and conversion of digital signals output by the ammonia sensor, so as to ensure the reliability of the signals. In the data processing process, the system can apply a filtering technology to carry out filtering processing on the acquired signals so as to remove potential noise and interference, thereby improving the accuracy of the data and the stability of the system. In addition, the data processing module 3 also performs data transmission with other devices through a communication interface, so as to realize information sharing with an external system or perform local storage on the data. When the received data are analyzed, the module can calculate the concentration of nitrogen oxides and the concentration of oxygen, and finally the concentration of ammonia is obtained. The processed data is properly stored in memory for later retrieval, analysis or history. In addition, the data processing module 3 also has the capability of receiving and processing external data, so that the data processing module is more comprehensive. Through the complete functional set, the data processing module 3 plays a core role in the whole system, so that the ammonia sensor control system is ensured to provide highly accurate and stable gas concentration information, and a reliable basis is provided for environmental monitoring and control.
The DFT integrated interface circuit 4 is configured to receive an impedance analog signal output by the ammonia sensor, and output the impedance analog signal to the ac impedance calculation module 5; the DFT integrated interface circuit 4 is used for processing an ac electric signal, and has the main task of receiving an impedance analog signal output by the ammonia sensor and processing the impedance analog signal by utilizing the corresponding relation between ac impedance and temperature. Through this process, the DFT integrated interface circuit 4 can accurately detect the current temperature information of the ammonia sensor. In operation, the module is connected to an ammonia gas sensor, receives an impedance analog signal, and performs a Discrete Fourier Transform (DFT) on the signal through a particular circuit design, converting the signal to a frequency domain representation. By analyzing the frequency domain information, the relation between the impedance signal and the temperature can be obtained, so that the current temperature of the ammonia sensor can be deduced. Finally, the DFT integrated interface circuit 4 sends the processed temperature information to the ac impedance calculation module 5, providing accurate input for subsequent impedance calculation. Through the process, the system can acquire the temperature information of the ammonia sensor in real time, and provide key basic data for temperature control and gas concentration calculation.
The alternating current impedance calculation module 5 is used for analyzing the frequency response characteristic of a thermistor (specifically, the zirconia internal resistance of the thermistor) on the ammonia sensor, measuring voltage and current signals in an alternating current circuit, calculating the impedance value of the circuit by using a calculation formula (Z=R+jX) of the impedance, obtaining the impedance value of the thermistor on the ammonia sensor, and detecting the temperature of the ammonia sensor at the moment; where R is a resistor, X is a reactance, and j is an imaginary unit.
The temperature control module 7 is used for receiving the actual temperature information of the ammonia gas sensor detected by the alternating current impedance calculation module 5 and outputting a temperature control signal to the heating drive circuit 10 according to the difference between the set temperature and the actual temperature; the temperature control module 7 is composed of a temperature sensor (ac impedance calculation), a controller (incorporating a temperature control algorithm), and an actuator (heating drive circuit 10). The ac impedance module detects the temperature, and the controller controls the actuator to operate according to the difference between the set temperature and the actual temperature, so as to control the heating driving circuit 10 to adjust the temperature. The main function of the module is that after knowing that a certain corresponding relation exists between the impedance value and the temperature of the ammonia sensor, the impedance signal of the ammonia sensor is input into the data processing module 3 for calculation processing, a temperature deviation signal value is obtained, and a control algorithm of active disturbance rejection control (Active Disturbance Rejective Control) is added into the module to control the temperature of the ammonia sensor and correct deviation. And the PWM principle can be utilized, because the digital signal is transmitted to the temperature control module 7, and is sent in a high-low level mode, the duty ratio of each period of the voltage signal can be adjusted to realize the control of the output voltage and the temperature.
The heating driving circuit 10 is used for heating and driving the ammonia sensor according to the received temperature control signal so as to match the actual temperature of the ammonia sensor with the set temperature; the heating drive circuit 10 plays a vital role in the ammonia sensor system. The working principle mainly comprises the steps of receiving a temperature control signal sent by a temperature control module 7 and heating and driving an ammonia sensor through an actual physical control means. First, the circuit receives an accurate temperature control signal from the temperature control module 7. This signal is generated based on the system's demand for sensor temperature, taking into account a preset temperature range and control algorithm. Next, upon receiving the temperature control signal, the heating drive circuit 10 performs heating of the ammonia gas sensor by a physical control means. This may include controlling the heating element or adjusting the current to ensure that the sensor remains within the optimum operating temperature range at all times. This process helps to improve the sensitivity and performance of the sensor. Meanwhile, the heating drive circuit 10 is typically equipped with a temperature sensor or other feedback mechanism for monitoring the temperature state of the actual sensor. The temperature feedback mechanism realizes closed-loop control, ensures that the sensor can maintain the optimal working temperature under different environmental conditions, and improves the detection accuracy and reliability. In summary, the heating driving circuit 10 provides effective temperature management for the ammonia sensor system through its controllable heating mechanism, so as to ensure that the sensor can maintain the optimal state under various working conditions, thereby improving the performance and stability of the whole system.
A communication module 6 for transmitting and receiving information; the system is a module for internal communication and external connection of the whole ammonia sensor detection system, and is mainly used for communication among various modules in the interior, such as transmitting the impedance information of the ammonia sensor to a temperature control module 7 and transmitting digital signals obtained by a data processing module 3, such as the concentration information of ammonia and oxygen, and the like, to an engine control unit (ECU 12) by utilizing a CAN communication module 8, so that the emission of ammonia is regulated jointly by combining other modules.
The CAN communication module 8 is used for constructing communication between the communication module 6 and the control equipment; and a controller area network (Controller Area Network, CAN) protocol is adopted to provide an efficient and reliable information transmission and communication mechanism for the system. The main tasks of the system comprise key functions such as data transmission, control instruction transmission, network communication, fault diagnosis and the like. The main function of the module is to transmit the concentration of nitrogen oxides, the concentration of O 2 and the concentration of NH 3 to other system components, such as an engine electronic control unit (ECU 12), through a CAN bus.
The wide linear amplifying circuit 1 is connected with the signal conversion module 2, the signal conversion module 2 is connected with the data processing module 3 and the communication module 6, the data processing module 3 is connected with the communication module 6, the DFT integrated interface circuit 4 is connected with the alternating current impedance calculation module 5, the alternating current impedance calculation module 5 is connected with the temperature control module 7 and the communication module 6, the temperature control module 7 is connected with the communication module 6 and the heating driving circuit 10, the communication module 6 is connected with the CAN communication module 8, and the CAN communication module 8 is connected with the control equipment.
In this embodiment: referring to fig. 1, the circuit for driving the ammonia gas sensor further includes a power module 9 for converting the input voltage into 3.3V and 5V direct currents, and supplying the direct currents to the modules and circuits.
The power module 9 is a key component in the ammonia sensor system, the input voltage is +12v, and the output provides +3.3v and +5v voltages required inside the system to meet the power requirements of each component. The main functions include voltage conversion, power distribution, stability and reliability guarantee and efficiency optimization. First, the power module 9 converts the input +12v voltage into +3.3v and +5v voltages required inside the system by a precise circuit design and voltage conversion technique. The conversion ensures that each element in the system can normally operate in a proper voltage range, and ensures the stability of the system. Secondly, the power module 9 is responsible for effectively distributing the generated +3.3v and +5v voltages to various components in the ammonia sensor system, including the DFT integrated interface circuit 4, the ac impedance calculation module 5, the CAN communication module 8, the data processing module 3, and the like. This power distribution mechanism ensures that each component is supported by a consistent and reliable power. In order to ensure the robustness of the system, the power module 9 adopts the designs of a voltage stabilizer, an overload protection circuit and the like, prevents the fluctuation of output voltage from generating adverse effect on the system, and cuts off the power supply when the current is abnormal, thereby protecting the system from damage. Finally, the power module 9 improves the energy efficiency of the whole system and reduces the energy waste through an efficiency optimization technology in the power conversion process. This provides a basic support for the reliability and long-term stable operation of ammonia sensor systems. In combination, the power module 9 provides stable and reliable power support for the entire ammonia sensor system through its precise design and versatility.
In this embodiment: referring to fig. 1, the control device includes an engine control unit ECU12 for implementing comprehensive monitoring, control and optimization of the running state of the automobile by connecting various sensors and data buses.
The engine control unit ECU12 is connected with various sensors and data buses, and the ECU12 realizes comprehensive monitoring, control and optimization of the running state of the automobile and is also responsible for realizing various functions. The ECU12 first collects the running state and environmental data of the vehicle in real time through various sensors connected to the vehicle, such as an ammonia sensor, a speed sensor, a temperature sensor, etc. The ECU12 then processes and analyzes these data in real time, applying advanced algorithms and logical reasoning to accurately grasp the vehicle state, and to recognize the driver's operational intent. Based on the information obtained by the processing, the ECU12 makes intelligent decisions to determine optimal engine operating parameters, vehicle handling strategies, etc., to meet performance, fuel efficiency, emissions, etc. The ECU12 converts the formulated steering strategy into specific actions by connecting to actuators, such as engine actuators, brake actuators, etc., to achieve precise steering of the various systems of the vehicle.
In this embodiment: referring to fig. 1, the DFT integrated circuit further includes a compensation resistor Rcal11 for compensating the deviated impedance value to the standard impedance value.
As a compensation resistor of the DFT integrated interface circuit, for the gas sensitive material in the ammonia sensor, there is an optimum temperature corresponding to a standard impedance value, and due to the difference between the chip materials and other physical effects, there may be a positive and negative deviation of the corresponding impedance value at the optimum temperature not being the standard impedance value. Therefore, by adding an Rcal11 compensation resistor, a function of compensating the impedance value with a certain deviation to a standard impedance value is added to the system, and after the temperature calibration is completed, the impedance measurement is carried out subsequently, so that a correct temperature value is corresponding.
In this embodiment: referring to fig. 1, the output temperature control signal output by the temperature control module 7 is a PWM signal.
Because the digital signal is transmitted to the temperature control module 7, the digital signal is transmitted in a high-low level mode, and the duty ratio of each period of the voltage signal can be adjusted to realize the control of the output voltage and the temperature.
The working principle of the invention is as follows: the allowance linear amplifying circuit 1 is used for receiving a voltage signal generated by the gas sensitive material on the ammonia sensor, amplifying the voltage signal in an allowance linear range, obtaining an amplified signal and outputting the amplified signal to the signal conversion module 2; the signal conversion module 2 is used for converting the input amplified signal into discrete digital signals and outputting the discrete digital signals to the data processing module 3; the data processing module 3 is used for receiving the digital signals, calculating the concentration of nitrogen oxides (NOX value) and the concentration of oxygen (O2 value) after filtering treatment, and finally obtaining the concentration of ammonia (NH 3 value); the DFT integrated interface circuit 4 is used for receiving the impedance analog signal output by the ammonia sensor and outputting the impedance analog signal to the alternating current impedance calculation module 5; the alternating current impedance calculation module 5 is used for analyzing the frequency response characteristic of the thermistor on the ammonia sensor, measuring voltage and current signals in the alternating current circuit, calculating the impedance value of the circuit by using a calculation formula (Z=R+jX) of the impedance, obtaining the impedance value of the thermistor on the ammonia sensor, and detecting the temperature of the ammonia sensor at the moment; the temperature control module 7 is used for receiving the actual temperature information of the ammonia gas sensor detected by the alternating current impedance calculation module 5, and outputting a temperature control signal to the heating driving circuit 10 according to the difference between the set temperature and the actual temperature; the heating driving circuit 10 is used for heating and driving the ammonia sensor according to the received temperature control signal so as to match the actual temperature of the ammonia sensor with the set temperature; the communication module 6 is used for transmitting and receiving information; the CAN communication module 8 is used to construct communication between the communication module 6 and the control device.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
Claims (7)
1. A method for driving an ammonia sensor, characterized in that the method for driving an ammonia sensor comprises the steps of:
Step 1, acquiring the actual temperature of an ammonia sensor;
Step 2, adjusting the actual temperature of the ammonia sensor to reach the set temperature of the ammonia sensor;
And step 3, acquiring voltage signals sent by gas sensitive materials for detecting the concentration of nitrogen oxides and oxygen on the ammonia sensor on the basis that the actual temperature of the ammonia sensor reaches the set temperature, and obtaining the concentration of the ammonia and the oxygen at present through operation treatment.
2. The method for driving an ammonia gas sensor according to claim 1, wherein step 1 specifically comprises:
Step 11, acquiring data of a thermosensitive zirconia internal resistance signal on an ammonia sensor to obtain resistance data of a thermosensitive material;
And step 12, acquiring the actual temperature of the ammonia sensor based on the one-to-one correspondence between the impedance of the thermosensitive material and the temperature.
3. A circuit for driving an ammonia sensor, the circuit for driving an ammonia sensor comprising:
the wide linear amplifying circuit is used for receiving the voltage signal generated by the gas sensitive material on the ammonia sensor, amplifying the voltage signal in a wide linear range, obtaining an amplified signal and outputting the amplified signal to the signal conversion module;
The signal conversion module is used for converting the input amplified signal into a discrete digital signal and outputting the discrete digital signal to the data processing module;
The data processing module is used for receiving the digital signals, calculating the concentration of nitrogen oxides and the concentration of oxygen after filtering treatment, and finally obtaining the concentration of ammonia;
The DFT integrated interface circuit is used for receiving the impedance analog signal output by the ammonia sensor and outputting the impedance analog signal to the alternating current impedance calculation module;
The alternating current impedance calculation module is used for analyzing the frequency response characteristic of the thermistor on the ammonia sensor, measuring voltage and current signals in the alternating current circuit, calculating the impedance value of the circuit by utilizing an impedance calculation formula, obtaining the impedance value of the thermistor on the ammonia sensor, and detecting the temperature of the ammonia sensor at the moment;
the temperature control module is used for receiving the actual temperature information of the ammonia sensor detected by the alternating current impedance calculation module and outputting a temperature control signal to the heating drive circuit according to the difference between the set temperature and the actual temperature;
The heating driving circuit is used for heating and driving the ammonia sensor according to the received temperature control signal so as to enable the actual temperature of the ammonia sensor to be matched with the set temperature;
the communication module is used for transmitting and receiving information;
The CAN communication module is used for constructing communication between the communication module and the control equipment;
The wide linear amplifying circuit is connected with the signal conversion module, the signal conversion module is connected with the data processing module and the communication module, the data processing module is connected with the communication module, the DFT integrated interface circuit is connected with the alternating current impedance calculation module, the alternating current impedance calculation module is connected with the temperature control module and the communication module, the temperature control module is connected with the communication module and the heating driving circuit, the communication module is connected with the CAN communication module, and the CAN communication module is connected with the control equipment.
4. A circuit for driving an ammonia gas sensor as defined in claim 3 further comprising a power module for converting the input voltage into 3.3V and 5V direct current, and supplying each module and each circuit.
5. A circuit for driving an ammonia gas sensor according to claim 3 wherein the control device comprises an engine control unit ECU for effecting comprehensive monitoring, control and optimization of the vehicle driving conditions by connecting various sensors and data buses.
6. A circuit for driving an ammonia gas sensor as defined in claim 3 wherein the DFT integrated circuit further comprises a compensation resistor Rcal for compensating the deviated impedance value to a standard impedance value.
7. A circuit for driving an ammonia gas sensor as defined in claim 3 wherein the output temperature control signal output by the temperature control module is a PWM signal.
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