Urea Detection Device and Method

Abstract

The present application relates to a urea detection device and method. The device includes: a urea sensor disposed in a urea tank to be measured, for detecting urea parameters in the urea tank; a driving module connected to the urea sensor, for supplying power to the urea sensor and driving the urea sensor to operate; a processing module connected to the urea sensor, for obtaining a detection signal output by the urea sensor, determining actual urea parameters according to the detection signal when the detection signal meets a first preset condition, and recording the actual urea parameters as the parameters of the urea in the urea tank when the actual urea parameters meet a second preset condition. Through two effectiveness judgments, the reliability and accuracy of urea quality detection are improved.

Description

Technical Field

[0001] This application relates to the technical field of vehicle exhaust treatment, and particularly to a urea detection device and method. Background Art

[0002] With the development of automotive technology and the increasing emphasis on environmental protection, the requirements for energy conservation and emission reduction of vehicles are also getting higher and higher. Urea is used in the vehicle exhaust after-treatment system. The exhaust after-treatment system sprays an aqueous urea solution into the vehicle exhaust passage through a nozzle, and uses the heat of the exhaust gas to hydrolyze urea to generate ammonia. Ammonia, as a reducing agent, can reduce nitrogen oxides in the vehicle exhaust, thereby reducing the pollution of vehicle exhaust to the environment. The quality of urea in the vehicle urea tank will directly affect the purification degree of the vehicle exhaust after-treatment system for vehicle exhaust. Therefore, it is necessary to detect the quality of urea. However, in traditional technologies, the detected data of urea quality are inaccurate. Summary of the Invention

[0003] Based on this, in view of the above technical problems, it is necessary to provide a urea detection device and method that can obtain more accurate urea quality data.

[0004] A urea detection device includes: a urea sensor disposed in a urea tank to be measured, for detecting urea parameters in the urea tank; a driving module connected to the urea sensor, for supplying power to the urea sensor and driving the urea sensor to work; a processing module connected to the urea sensor, for acquiring a detection signal output by the urea sensor, when the detection signal meets a first preset condition, determining actual urea parameters according to the detection signal, and when the actual urea parameters meet a second preset condition, recording the actual urea parameters as the parameters of urea in the urea tank.

[0005] In one embodiment, the driving module is used to periodically drive the urea sensor to work at fixed time intervals; the processing module is used to determine that the current detection signal meets the first preset condition when the time interval between acquiring the current detection signal and the previous detection signal is greater than a set time length, and the frequency of the current detection signal is greater than a set frequency.

[0006] In one embodiment, the processing module is used to determine an actual urea concentration according to the actual urea parameters, and when the actual urea concentration is less than an upper concentration limit, determine that the actual urea parameters meet the second preset condition.

[0007] In one embodiment, the urea detection device includes: a voltage division module, which is connected to an external power supply module and is used to divide the voltage provided by the external power supply module into a first voltage for output; the driving module includes a power supply unit and a driving unit, where: the high-voltage side input end of the power supply unit is connected to the external power supply module, the low-voltage side input end of the power supply unit is connected to the voltage division module, the high-voltage side output end of the power supply unit is connected to the driving unit, the low-voltage side output end of the power supply unit is connected to the negative electrode of the urea sensor, and the power supply unit is used to supply power to the driving unit and the urea sensor; the signal input end of the driving unit is connected to an external pulse source, the power supply input end of the driving unit is connected to the high-voltage side output end of the power supply unit, and the signal output end of the driving unit is connected to the positive electrode of the urea sensor. The driving unit is used to provide a preset pulse signal for the urea sensor to drive the urea sensor to work.

[0008] In one embodiment, the power supply unit includes: a first filter, the first end of the first filter is used as the high-voltage side input end of the power supply unit, and the second end of the first filter is equivalently connected; a second filter, the first end of the second filter is connected to the equivalent connection, and the second end of the second filter is used as the low-voltage side input end of the power supply unit and is connected to the negative electrode of the urea sensor; a load resistor, the first end of the load resistor is connected to the first end of the first filter, and the second end of the load resistor is used as the high-voltage side output end of the power supply unit.

[0009] In one embodiment, the first filter and the second filter are high-pass filters.

[0010] In one embodiment, the driving unit includes: a frequency divider, the input end of the frequency divider is used as the signal input end of the driving unit, and the frequency divider is used to output a first pulse signal with a preset frequency; a first amplifier circuit, the input end of the first amplifier circuit is connected to the output end of the frequency divider, the power supply end of the first amplifier circuit is used as the power supply input end of the driving unit, and the first amplifier circuit is used to amplify the pulse signal with the preset frequency by a preset magnification to obtain a second pulse signal; a first impedance matching circuit, the input end of the first impedance matching circuit is connected to the output end of the first amplifier circuit, and the output end of the first impedance matching circuit is used as the signal output end of the driving unit. The characteristic impedance of the first impedance matching circuit is the same in magnitude and phase as that of the urea sensor.

[0011] In one embodiment, the processing module includes: an acquisition unit connected to the urea sensor, configured to obtain the sensing signal obtained by the urea sensor and convert the sensing signal into the detection signal for transmission; and a processing unit connected to the acquisition unit, configured to determine the actual urea parameter according to the detection signal when the detection signal meets a first preset condition, and record the actual urea parameter as the parameter of the urea in the urea tank when the actual urea parameter meets a second preset condition.

[0012] In one embodiment, the acquisition unit includes: a second impedance matching circuit, an input end of the second impedance matching circuit being connected to the urea sensor, wherein the magnitude and phase of the characteristic impedance of the second impedance matching circuit are the same as those of the urea sensor; a second amplification circuit, an input end of the second amplification circuit being connected to an output end of the second impedance matching circuit, the second amplification circuit being configured to amplify the sensing signal; and a comparison circuit, an input end of the comparison circuit being connected to the output end of the second amplification circuit, an output end of the comparison circuit being connected to the processing unit, the comparison circuit being configured to output a high-level signal when the sensing signal is greater than a voltage threshold.

[0013] A urea detection method is applied to the aforementioned urea detection device, and the method includes:

[0014] Obtain the detection signal output by the urea sensor;

[0015] Determine whether the detection signal meets a first preset condition;

[0016] If the detection signal meets the first preset condition, determine the actual urea parameter according to the detection signal;

[0017] Determine whether the actual urea parameter meets a second preset condition;

[0018] If the actual urea parameter meets the second preset condition, record it as the parameter of the urea in the urea tank.

[0019] The above urea detection device and method. The urea detection device can detect urea parameters in the urea tank by setting a urea sensor. By setting a driving module, power can be supplied to the urea sensor to make the urea sensor powered on, and the urea sensor can be driven to work. By setting a processing module, the detection signal output by the urea sensor can be obtained, and then it can be determined whether the detection signal meets the first preset condition. Thus, before the detection signal is parsed, the first validity judgment of the detection signal is performed, and the detection signals that do not meet the first preset condition can be filtered out. Then, the actual urea parameters are determined according to the detection signals that meet the first preset condition, that is, the detection signals that meet the first preset condition are parsed and processed to obtain the actual urea parameters included in the detection signals. Then, it is determined whether the actual urea parameters meet the second preset condition, thereby performing the second validity judgment on the actual urea parameters, and the actual urea parameters that do not meet the second preset condition can be filtered out. Then, the actual urea parameters that meet the second preset condition are recorded as the urea parameters in the urea tank. Through the first validity judgment of the detection signal, after the signal is received, the interfering signals that do not meet the conditions can be filtered out, thereby improving the accuracy of the obtained urea quality data, and avoiding parsing the detection signals that do not meet the conditions, reducing the time for subsequent parsing of the detection signals, and improving the detection efficiency. Then, the second validity judgment is performed on the actual urea parameters, and the incorrect actual urea parameters can be filtered out. The actual urea parameters that have passed the two validity judgments are used as the urea parameters in the urea tank, improving the reliability and accuracy of urea quality detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of a urea detection device in an embodiment;

[0022] Figure 2 It is a schematic structural diagram of a urea detection device in another embodiment;

[0023] Figure 3 It is a schematic structural diagram of a urea detection device in yet another embodiment;

[0024] Figure 4 It is a schematic structural diagram of a urea detection device in yet another embodiment;

[0025] Figure 5 It is a schematic structural diagram of a urea detection device in yet another embodiment;

[0026] Figure 6 It is a schematic structural diagram of a urea detection device in yet another embodiment;

[0027] Figure 7 It is a schematic structural diagram of a urea detection device in yet another embodiment;

[0028] Figure 8 It is a flowchart of a urea detection method in one embodiment.

[0029] Description of reference numerals:

[0030] 10 - urea sensor, 20 - drive module, 30 - processing module, 40 - urea tank, 50 - voltage division module, 21 - power supply unit, 22 - drive unit, 60 - power module, 70 - pulse source, 23 - first filter, 24 - second filter, 25 - load resistor, 26 - frequency divider, 27 - first amplifier circuit, 28 - first impedance matching circuit, 31 - acquisition unit, 32 - processing unit, 33 - second impedance matching circuit, 34 - second amplifier circuit, 35 - comparison circuit. Detailed implementation manners

[0031] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0033] It can be understood that the terms "first", "second", etc. used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0034] Spatial relationship terms such as "under", "below", "beneath", "underneath", "above", "over", etc. can be used herein to describe the relationship of one element or feature shown in the figure with other elements or features. It should be understood that, in addition to the orientations shown in the figure, spatial relationship terms also include different orientations of the device during use and operation. For example, if the device in the attached drawing is flipped, an element or feature described as "under other elements" or "beneath it" or "under it" will be oriented "above" other elements or features. Therefore, the exemplary terms "under" and "beneath" can include both the upper and lower orientations. In addition, the device may also include additional orientations (such as rotating 90 degrees or other orientations), and the spatial descriptors used herein are accordingly interpreted.

[0035] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediate element. In addition, for "connection" in the following embodiments, if there is a transfer of electrical signals or data between the connected objects, it should be understood as "electrically connected", "communicatively connected", etc.

[0036] As used herein, the singular forms "a", "an", and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that terms such as "comprise / include" or "have" etc. specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0037] In one embodiment, as Figure 1 shown, a urea detection device is provided, including: a urea sensor 10, a drive module 20, and a processing module 30, wherein:

[0038] The urea sensor 10 is disposed in the urea tank 40 to be measured for detecting urea parameters in the urea tank 40.

[0039] Among them, the urea sensor 10 may include an ultrasonic probe, a temperature sensor, etc. By means of ultrasonic detection, information such as the concentration, liquid level, and temperature of urea can be obtained and converted into electrical signals for transmission.

[0040] The drive module 20 is connected to the urea sensor 10 for supplying power to the urea sensor 10 and driving the urea sensor 10 to operate.

[0041] Among them, the driving module 20 can, on the one hand, provide a driving current for the urea sensor 10 so that the urea sensor 10 can be powered on, and on the other hand, can provide a driving pulse signal for the urea sensor 10 to drive the urea sensor 10 to work.

[0042] The processing module 30, connected to the urea sensor 10, is used to obtain the detection signal output by the urea sensor 10. When the detection signal meets the first preset condition, the actual urea parameter is determined according to the detection signal. When the actual urea parameter meets the second preset condition, the actual urea parameter is recorded as the parameter of the urea in the urea tank 40.

[0043] Among them, the first preset condition and the second preset condition are preset in the processing module 30. After receiving the detection signal sent by the urea sensor 10, the processing module 30 first judges the rationality of the detection signal according to the first preset condition, so as to judge whether the received detection signal is a valid detection signal or an invalid interference signal, and can filter out the invalid interference signal. Then for the valid detection signal, the actual urea parameter is determined according to the detection signal, and then the rationality of the actual urea parameter is judged according to the second preset condition, so as to judge whether the actual urea parameter conforms to the actual situation, so that the wrong actual urea parameter can be filtered out. The actual urea parameter that has passed two rationality judgments is an effective and highly reliable urea parameter, and can be determined as the parameter of the urea in the urea tank 40.

[0044] In this embodiment, the urea detection device can detect the urea parameters in the urea tank 40 by setting the urea sensor 10. By setting the driving module 20, the urea sensor 10 can be powered on and the urea sensor 10 can be driven to work. By setting the processing module 30, the detection signal output by the urea sensor 10 can be obtained, and then it is determined whether the detection signal meets the first preset condition. Thus, before the detection signal is parsed, the first validity judgment of the detection signal is carried out, and the detection signals that do not meet the first preset condition can be filtered out. Then, the actual urea parameters are determined according to the detection signals that meet the first preset condition, that is, the detection signals that meet the first preset condition are parsed and processed to obtain the actual urea parameters included in the detection signals. Then, it is determined whether the actual urea parameters meet the second preset condition, so that the second validity judgment of the actual urea parameters is carried out, and the actual urea parameters that do not meet the second preset condition can be filtered out. Then, the actual urea parameters that meet the second preset condition are recorded as the urea parameters in the urea tank 40. Through the first validity judgment of the detection signal, the interference signals that do not meet the conditions can be filtered out after the signal is received, thereby improving the accuracy of the obtained urea quality data, avoiding the parsing of the detection signals that do not meet the conditions, reducing the time for subsequent parsing of the detection signals, and improving the detection efficiency. Then, the second validity judgment of the actual urea parameters is carried out, and the incorrect actual urea parameters can be filtered out. The actual urea parameters that have passed the two validity judgments are used as the urea parameters in the urea tank 40, improving the reliability and accuracy of the urea quality detection.

[0045] In one embodiment, the driving module is used to drive the urea sensor to work periodically at fixed time intervals.

[0046] Wherein, the urea sensor includes an ultrasonic probe, so the driving module periodically provides a pulse signal with a set frequency to the urea sensor at fixed time intervals to drive the ultrasonic probe to emit ultrasonic waves.

[0047] The processing module is used to determine that the current detection signal meets the first preset condition when the time interval between obtaining the current detection signal and obtaining the previous detection signal is greater than the set time length and the frequency of the current detection signal is greater than the set frequency.

[0048] Among them, the set duration is set according to the interval time of the driving module providing a pulse signal to the urea sensor, and can be set to be slightly less than the interval time of the driving module providing a pulse signal to the urea sensor. Therefore, as long as the time interval between the received detection signal and the previous detection signal is less than the set duration, it does not conform to the normal interval time of the two-terminal detection signals. Therefore, it can be directly determined that the currently received detection signal is an invalid interference signal. And the detection signal is designed as a high-frequency pulse signal. If the frequency is less than the set frequency, it means that the signal is also an invalid interference signal. Thus, on the one hand, the validity of the detection signal is judged by the time interval between receiving two detection signals, and on the other hand, the validity of the detection signal is judged by the frequency of the received detection signal, which can effectively filter out interference signals.

[0049] Exemplarily, the processing module can start timing at the moment of receiving the rising edge of the previous detection signal and stop timing until receiving the rising edge of the next detection signal, then the interval duration between the two detection signals can be obtained.

[0050] In this embodiment, on the one hand, the validity of the detection signal is judged by the time interval between receiving two detection signals, and on the other hand, the validity of the detection signal is judged by the frequency of the received detection signal, which can effectively filter out interference signals and improve the reliability of urea detection.

[0051] In one embodiment, the processing module is used to determine the actual urea concentration according to the actual urea parameters. When the actual urea concentration is less than the concentration upper limit, it is determined that the actual urea parameters meet the second preset condition.

[0052] Among them, after determining the actual urea parameters according to the detection data, the urea concentration in the actual urea parameters is used as an index to judge the validity of the actual urea parameters. The actual urea concentration is compared with the concentration upper limit preset in the processing module. Theoretically, the actual urea concentration will not exceed the concentration upper limit. Therefore, the rationality of the actual urea concentration can be judged according to the concentration upper limit, and the incorrect actual urea concentration data can be filtered out.

[0053] Exemplarily, the effective value of the concentration upper limit is obtained by looking up a table according to the effective temperature value in the actual urea parameters.

[0054] Exemplarily, the processing module is connected to the in-vehicle terminal of the vehicle through a Controller Area Network (CAN) communication bus, and can transmit the urea parameters to the in-vehicle terminal.

[0055] In this embodiment, the urea concentration in the actual urea parameters is used as an index to judge the effectiveness of the actual urea parameters, so as to effectively filter out the incorrect actual urea concentration data and improve the accuracy and reliability of urea detection.

[0056] In one embodiment, as Figure 2 shown, the urea detection device includes a voltage division module 50. The driving module includes a power supply unit 21 and a driving unit 22.

[0057] The voltage division module 50 is connected to an external power supply module 60 and is used to divide the voltage provided by the external power supply module 60 into a first voltage for output.

[0058] Among them, the voltage division module 50 can be a digital voltage divider, a low dropout regulator (LDO), a voltage dividing resistor or other devices with a voltage dividing function, which can divide the voltage output by the power supply module 60 into a suitable first voltage as the low voltage side of the power supply.

[0059] Exemplarily, the power supply module 60 can be a vehicle power supply.

[0060] The high-voltage side input end of the power supply unit 21 is connected to the external power supply module 60, the low-voltage side input end of the power supply unit 21 is connected to the voltage division module 50, the high-voltage side output end of the power supply unit 21 is connected to the driving unit 22, and the low-voltage side output end of the power supply unit 21 is connected to the negative electrode of the urea sensor 10. The power supply unit 21 is used to supply power to the driving unit 22 and the urea sensor 10.

[0061] Among them, the high-voltage side input end of the power supply unit 21 directly receives the voltage provided by the external power supply module 60, and the low-voltage side input end of the power supply unit 21 receives the voltage after being divided by the voltage division module 50. Therefore, the voltage on the high-voltage side of the power supply unit 21 is greater than the voltage on the low-voltage side, so that a pressure difference can be formed to obtain a supply current. Secondly, the voltage provided by the power supply unit 21 is only less than the voltage of the power supply module 60, so the voltage is smaller and safer.

[0062] Among them, the low-voltage side output end of the power supply unit 21 is connected to the negative electrode of the urea sensor 10, and the high-voltage side output end of the power supply unit 21 is connected to the positive electrode of the urea sensor 10 through the driving unit 22, so as to realize the power supply to the urea sensor 10.

[0063] The signal input end of the driving unit 22 is connected to the external pulse source 70, the power supply input end of the driving unit 22 is connected to the high-voltage side output end of the power supply unit 21, and the signal output end of the driving unit 22 is connected to the positive electrode of the urea sensor 10. The driving unit 22 is used to provide a preset pulse signal for the urea sensor 10 to drive the urea sensor 10 to work.

[0064] Among them, the signal input end of the driving unit 22 can receive an external pulse signal, process the pulse signal, and then supply it to the positive electrode of the urea sensor 10 through the signal output end, so as to drive the operation of the urea sensor 10. And the power supply input end of the driving unit 22 is connected to the high-voltage side output end of the power supply unit 21 to receive the power supply from the power supply unit 21.

[0065] Exemplarily, the pulse source 70 can be a pulse generator, which can provide pulse drive signals, clock signals, etc.

[0066] In this embodiment, by setting the voltage dividing module 50, the voltage output by the power supply module 60 is divided, and then the divided voltage is used as the low voltage and supplied to the low-voltage side of the driving module 20. Then, the voltage output by the power supply module 60 without being divided by the voltage dividing module 50 is used as the high voltage and supplied to the high-voltage side of the driving module 20. Therefore, the positive electrode of the urea sensor 10 is directly powered by the voltage provided by the power supply module 60, and the negative electrode of the urea sensor 10 is powered by the voltage provided by the power supply module 60 after being divided by the voltage dividing module 50. Thus, the supply voltage of the urea sensor 10 all comes from the power supply module 60, and there is no need to separately set a high-voltage driving module 20. And compared with the traditional scheme where the negative electrode of the urea sensor 10 is grounded, in this application, a low voltage is provided for the negative electrode of the urea sensor 10, which can make the voltages of the positive and negative electrodes of the urea sensor 10 fluctuate synchronously and with a smaller fluctuation degree when the voltage of the power supply module 60 fluctuates, thereby avoiding damage to the urea sensor 10 and improving the service life of the urea sensor 10.

[0067] In one embodiment, as Figure 3 shown, the power supply unit includes: a first filter 23, a second filter 24, and a load resistor 25, where:

[0068] The first end of the first filter 23 serves as the high-voltage side input end of the power supply unit 21, and the second end of the first filter 23 is equivalently connected to the ground.

[0069] The first end of the second filter 24 is equivalently connected to the ground, and the second end of the second filter 24 serves as the low-voltage side input end of the power supply unit 21 and is connected to the negative electrode of the urea sensor 10.

[0070] Among them, both the first filter 23 and the second filter 24 can be capacitive filters, and the capacitance value of the first filter 23 is greater than 10 uF, which can filter the input electrical signal. In addition, the first filter 23 and the second filter 24 are also equivalently connected to the ground. When the pulse signal is in the low-level stage, the impedance between the first filter 23 and the second filter 24 and the ground is infinite, so as to play an isolation role and avoid the low-level pulse signal from being transmitted to the probe and affecting the accuracy of the probe sampling.

[0071] Exemplarily, the first filter 23 and the second filter 24 are high-pass filters.

[0072] One end of the load resistor 25 is connected to one end of the first filter 23, and the other end of the load resistor 25 serves as the high-voltage side output terminal of the power supply unit 21.

[0073] In this embodiment, by setting the filter and the load resistor 25, the signal can be filtered and isolated, making the signal transmitted in the circuit more accurate.

[0074] In one embodiment, as Figure 4 shown, the driving unit includes: a frequency divider 26, a first amplifier circuit 27, and a first impedance matching circuit 28, where:

[0075] The input end of the frequency divider 26 serves as the signal input end of the driving unit 22, and the frequency divider 26 is used to output a first pulse signal with a preset frequency.

[0076] Among them, the frequency divider 26 can receive the pulse signal transmitted from the external pulse source 70, and then adjust the frequency of the pulse signal. The frequency is adjusted using the following formula: f S2 = n / mf S1 , where f S2 is the pulse signal after frequency adjustment, f S1 is the pulse signal before frequency adjustment, and n and m are positive integers, and n < m.

[0077] Exemplarily, the number of pulses of the pulse signal is greater than or equal to 2. The frequency of the pulse signal after frequency adjustment is around 1 MHz.

[0078] The input end of the first amplifier circuit 27 is connected to the output end of the frequency divider 26. The power supply end of the first amplifier circuit 27 serves as the power supply input end of the driving unit 22. The first amplifier circuit 27 is used to amplify the pulse signal with a preset frequency by a preset magnification to obtain a second pulse signal.

[0079] Among them, the first amplifier circuit 27 can amplify the pulse signal. The amplification is performed using the following formula: V S2 = K·V S1 where V S2 is the amplified pulse signal, V S1 is the pulse signal before amplification, and K is the amplification factor.

[0080] Exemplarily, the first amplifier circuit 27 includes a triode. The base of the triode is connected to the output end of the frequency divider 26, the collector of the triode is connected to the high-voltage side output terminal of the power supply unit 21, and the emitter of the triode is grounded. The amplification function can be achieved.

[0081] The input end of the first impedance matching circuit 28 is connected to the output end of the first amplifying circuit 27. The output end of the first impedance matching circuit 28 serves as the signal output end of the driving unit 22. The magnitude and phase of the characteristic impedance of the first impedance matching circuit 28 are the same as those of the urea sensor 10.

[0082] Among them, the first impedance matching circuit 28 has complex impedance characteristics. The pulse signal passing through the first impedance matching circuit 28 has the characteristic that the argument ∈ (-90°, 0]. Since the urea sensor 10 has complex impedance characteristics, therefore, the impedance characteristics of the first impedance matching circuit 28 need to be the same as those of the urea sensor 10, so as to better match the impedance of the urea sensor 10 and make the transmitted signal more accurate.

[0083] Exemplarily, the first impedance matching circuit 28 includes a capacitor and a resistor, and can achieve the matching of complex impedance.

[0084] In this embodiment, by setting the frequency divider 26, the first amplifying circuit 27, and the first impedance matching circuit 28, a pulse signal required by the urea sensor 10 can be provided, which is convenient for driving the urea sensor 10 and makes the pulse signal provided for the urea sensor 10 more accurate.

[0085] In one embodiment, as Figure 5 shown, the processing module includes: an acquisition unit 31 and a processing unit 32, where:

[0086] The acquisition unit 31 is connected to the urea sensor 10 and is used to obtain the sensing signal obtained by the urea sensor 10 and convert the sensing signal into a detection signal for transmission.

[0087] The processing unit 32 is connected to the acquisition unit 31 and is used to determine whether the detection signal meets the first preset condition. If the detection signal meets the first preset condition, the actual urea parameter is determined according to the detection signal, and it is determined whether the actual urea parameter meets the second preset condition. If the actual urea parameter meets the second preset condition, it is recorded as the urea parameter in the urea tank 40.

[0088] In this embodiment, by setting the acquisition unit 31, the acquisition of the sensing signal obtained by the urea sensor 10 is realized. By setting the processing unit 32, the detection signal can be processed.

[0089] In one embodiment, as Figure 6 shown, the acquisition unit includes: a second impedance matching circuit 33, a second amplifying circuit 34, and a comparison circuit 35, where:

[0090] The input end of the second impedance matching circuit 33 is connected to the urea sensor 10. Among them, the magnitude and phase of the characteristic impedance of the second impedance matching circuit 33 are the same as those of the urea sensor 10.

[0091] Among them, the second impedance matching circuit 33 has a complex impedance characteristic, and the phase ∈ (-90°, 0). Thus, it can match the impedance of the urea sensor 10, enabling the signal output by the urea sensor 10 to be transmitted more accurately.

[0092] The input end of the second amplifier circuit 34 is connected to the output end of the second impedance matching circuit 33, and the second amplifier circuit 34 is used to amplify the sensing signal.

[0093] Exemplarily, the amplification factor of the second amplifier circuit 34 is greater than or equal to 20 dB.

[0094] Exemplarily, the second amplifier circuit 34 includes an operational amplifier.

[0095] The input end of the comparison circuit 35 is connected to the output end of the second amplifier circuit 34, and the output end of the comparison circuit 35 is connected to the processing unit 32. The comparison circuit 35 is used to output a high-level signal when the sensing signal is greater than the voltage threshold.

[0096] Exemplarily, the reference voltage can be obtained by voltage division of the power supply module 60. The voltage threshold, i.e., the reference voltage, can be half of the output voltage of the power supply module 60. The comparison circuit 35 has a hysteresis characteristic.

[0097] Exemplarily, the comparison circuit 35 includes a comparator, and one input end of the comparator is used to receive the reference voltage.

[0098] In this embodiment, by setting the second impedance matching circuit, the second amplifier circuit, and the comparison circuit, the impedance of the probe can be matched, enabling the sensing signal to be transmitted more accurately, amplifying the received sensing signal of the probe, and shaping the amplified waveform, thereby facilitating the provision of a more accurate and easily processable detection signal for the subsequent processing unit.

[0099] Exemplarily, as Figure 7 shown, it is a detailed structure diagram of the urea detection device. Both the first impedance matching circuit and the second impedance matching circuit are connected to the positive electrode of the urea sensor, and the first impedance matching circuit and the second impedance matching circuit work in a time-sharing manner. For example, when the first impedance matching circuit provides a pulse signal to the urea sensor, the second impedance matching circuit does not receive the sensing signal. When the second impedance matching circuit receives the sensing signal, the first impedance matching circuit stops providing the pulse signal to the urea sensor.

[0100] In one embodiment, as Figure 8 shown, a urea detection method is provided, which is applied to the urea detection device as described above. The method includes:

[0101] Step S800: Obtain the detection signal collected by the urea sensor.

[0102] Step S810: Determine whether the detection signal meets the first preset condition. If the detection signal meets the first preset condition, execute Step S820; otherwise, execute Step S830.

[0103] Step S820: Determine the actual urea parameter according to the detection signal.

[0104] Step S830: Delete the detection signal.

[0105] Step S840: Determine whether the actual urea parameter meets the second preset condition. If the actual urea parameter meets the second preset condition, execute Step S850; otherwise, execute Step S860.

[0106] Step S850: Record the actual urea parameter as the urea parameter in the urea tank.

[0107] Step S860: Delete the actual urea parameter.

[0108] In this embodiment, the detection signal output by the urea sensor is obtained, and then it is determined whether the detection signal meets the first preset condition. Thus, a first validity judgment is made on the detection signal before parsing the detection signal, and the detection signals that do not meet the first preset condition can be filtered out. Then, the actual urea parameter is determined according to the detection signal that meets the first preset condition, that is, the detection signal that meets the first preset condition is parsed to obtain the actual urea parameter included in the detection signal. Then, it is determined whether the actual urea parameter meets the second preset condition, thus making a second validity judgment on the actual urea parameter, and the actual urea parameters that do not meet the second preset condition can be filtered out. Then, the actual urea parameter that meets the second preset condition is recorded as the urea parameter in the urea tank. Through the first validity judgment of the detection signal, the interference signals that do not meet the conditions can be filtered out after receiving the signal, thus improving the accuracy of the obtained urea quality data, and avoiding parsing the detection signals that do not meet the conditions, reducing the subsequent parsing time of the detection signals, and improving the detection efficiency. Then, a second validity judgment is made on the actual urea parameter, which can filter out the incorrect actual urea parameters, and the actual urea parameters that have passed the two validity judgments are used as the urea parameters in the urea tank, improving the reliability and accuracy of the urea quality detection.

[0109] It should be understood that although Figure 8 the steps in the flowchart are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, Figure 8At least some of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily executed and completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in rotation with at least some of the steps or stages in other steps or other steps.

[0110] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database or other medium used in the various embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0111] In the description of this specification, the description with reference to terms such as "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or features described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0112] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0113] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A urea detection device, characterized in that, Including: A urea sensor, disposed in a urea tank to be measured, for detecting urea parameters in the urea tank; A driving module, connected to the urea sensor, for supplying power to the urea sensor and driving the urea sensor to work periodically at fixed time intervals; A processing module, connected to the urea sensor, for obtaining a detection signal output by the urea sensor, determining actual urea parameters according to the detection signal when the detection signal meets a first preset condition, and recording the actual urea parameters as the urea parameters in the urea tank when the actual urea parameters meet a second preset condition; The processing module is configured to determine that the current detection signal meets the first preset condition when the time interval between obtaining the current detection signal and obtaining the previous detection signal is greater than a set time length and the frequency of the current detection signal is greater than a set frequency; The processing module is configured to determine actual urea concentration according to the actual urea parameters, and determine that the actual urea parameters meet the second preset condition when the actual urea concentration is less than an upper concentration limit; A voltage dividing module, connected to an external power supply module, for dividing the voltage provided by the external power supply module and outputting a first voltage; The driving module includes a power supply unit and a driving unit, wherein: The high-voltage side input end of the power supply unit is connected to the external power supply module, the low-voltage side input end of the power supply unit is connected to the voltage dividing module, the high-voltage side output end of the power supply unit is connected to the driving unit, the low-voltage side output end of the power supply unit is connected to the negative electrode of the urea sensor, and the power supply unit is used to supply power to the driving unit and the urea sensor; The signal input end of the driving unit is connected to an external pulse source, the power supply input end of the driving unit is connected to the high-voltage side output end of the power supply unit, the signal output end of the driving unit is connected to the positive electrode of the urea sensor, and the driving unit is used to provide a preset pulse signal to drive the urea sensor to work.

2. The urea detection device according to claim 1, characterized in that The power supply unit includes: A first filter, the first end of the first filter serves as the high-voltage side input end of the power supply unit, and the second end of the first filter is equivalently connected; A second filter, the first end of the second filter is connected to the equivalent ground, and the second end of the second filter serves as the low-voltage side input end of the power supply unit and is connected to the negative electrode of the urea sensor; A load resistor, the first end of the load resistor is connected to the first end of the first filter, and the second end of the load resistor serves as the high-voltage side output end of the power supply unit.

3. The urea detection device according to claim 2, characterized in that, The first filter and the second filter are high-pass filters.

4. The urea detection device according to claim 1, characterized in that, The driving unit includes: A frequency divider, the input end of the frequency divider serves as the signal input end of the driving unit, and the frequency divider is used to output a first pulse signal with a preset frequency; A first amplification circuit, the input end of the first amplification circuit is connected to the output end of the frequency divider, the power supply end of the first amplification circuit serves as the power supply input end of the driving unit, and the first amplification circuit is used to amplify the pulse signal of the preset frequency by a preset magnification to obtain a second pulse signal; A first impedance matching circuit, the input end of the first impedance matching circuit is connected to the output end of the first amplification circuit, the output end of the first impedance matching circuit serves as the signal output end of the driving unit, and the magnitude and phase of the characteristic impedance of the first impedance matching circuit are the same as those of the urea sensor.

5. The urea detection device according to claim 1, characterized in that, The processing module includes: An acquisition unit, connected to the urea sensor, configured to obtain the sensing signal obtained by the urea sensor and convert the sensing signal into the detection signal for transmission; A processing unit, connected to the acquisition unit, configured to determine the actual urea parameter according to the detection signal when the detection signal meets the first preset condition, and record the actual urea parameter as the parameter of the urea in the urea tank when the actual urea parameter meets the second preset condition.

6. The urea detection device according to claim 5, characterized in that, The acquisition unit includes: A second impedance matching circuit, the input end of the second impedance matching circuit is connected to the urea sensor, wherein the magnitude and phase of the characteristic impedance of the second impedance matching circuit are the same as those of the urea sensor; A second amplification circuit, the input end of the second amplification circuit is connected to the output end of the second impedance matching circuit, and the second amplification circuit is used to amplify the sensing signal; A comparison circuit, the input end of the comparison circuit is connected to the output end of the second amplification circuit, the output end of the comparison circuit is connected to the processing unit, and the comparison circuit is configured to output a high-level signal when the sensing signal is greater than the voltage threshold.

Images