CN116147852A - LNG leakage detection circuit, system and LNG commercial vehicle - Google Patents
LNG leakage detection circuit, system and LNG commercial vehicle Download PDFInfo
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- CN116147852A CN116147852A CN202211352470.5A CN202211352470A CN116147852A CN 116147852 A CN116147852 A CN 116147852A CN 202211352470 A CN202211352470 A CN 202211352470A CN 116147852 A CN116147852 A CN 116147852A
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- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/16—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using electric detection means
- G01M3/18—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using electric detection means for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/30—Use of alternative fuels, e.g. biofuels
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Abstract
The invention discloses an LNG leakage detection circuit, an LNG leakage detection system and an LNG commercial vehicle, and relates to the technical field of LNG leakage detection, comprising the following steps: the device comprises a sensor signal acquisition circuit, a voltage reference circuit and a comparison judging circuit; the voltage judging circuit is connected with the sensor signal acquisition circuit and the voltage reference circuit; the sensor signal acquisition circuit is used for outputting a first signal voltage and a second signal voltage at a first signal end and a second signal end respectively according to the LNG concentration and the working state of the sensor; the voltage reference circuit is used for outputting a first reference voltage and a second reference voltage at a first reference end and a second reference end respectively; the comparison judging circuit is used for comparing the first signal voltage with the first reference voltage so as to judge whether the sensor works normally or not; and when the sensor works normally, the comparison judging circuit is also used for comparing the second signal voltage with the second reference voltage so as to judge whether LNG leakage exists or not. The invention can avoid the error of the detection result caused by the sensor fault and improve the accuracy of LNG leakage detection.
Description
Technical Field
The invention relates to the technical field of LNG leakage detection, in particular to an LNG leakage detection circuit, an LNG leakage detection system and an LNG commercial vehicle.
Background
At present, the risk of leakage exists in the pipeline connection of liquefied natural gas (Liquefied Natural Gas, LNG for short) commercial vehicles, the LNG is liquid at-162 ℃, the LNG used by the combustion of vehicle engines needs to be vaporized into gas at-30-60 ℃, the leakage risk exists in the pipeline connection and sealing in the process, and from the safety aspect, the requirements of regulations are as follows: if LNG leaks, the system needs to give an alarm in time to remind a driver to carry out maintenance treatment.
The existing gas sensor for detecting LNG leakage converts LNG concentration into voltage acquisition signals through an LNG concentration sensitive resistor in the gas sensor. However, when the sensor fails, an error detection result is caused, interference is brought to a user, and the user cannot be timely reminded of identifying risks.
Disclosure of Invention
The embodiment of the invention provides an LNG leakage detection circuit, an LNG leakage detection system and an LNG commercial vehicle, and aims to solve the technical problem that detection results are wrong due to sensor faults in the existing detection of electric Lewis in the related art.
In a first aspect, there is provided an LNG leak detection circuit comprising: the device comprises a sensor signal acquisition circuit, a voltage reference circuit and a comparison judging circuit;
the voltage judging circuit is connected with the sensor signal acquisition circuit and the voltage reference circuit;
the sensor signal acquisition circuit is used for outputting a first signal voltage and a second signal voltage at a first signal end and a second signal end respectively according to the LNG concentration and the working state of the sensor;
the voltage reference circuit is used for outputting a first reference voltage and a second reference voltage at a first reference end and a second reference end respectively;
the comparison judging circuit is used for comparing the first signal voltage with the first reference voltage so as to judge whether the sensor works normally or not; and when the sensor works normally, the comparison judging circuit is also used for comparing the second signal voltage with the second reference voltage so as to judge whether LNG leakage exists or not.
In some embodiments, the comparison and judgment circuit is configured to compare the first signal voltage with the first reference voltage to judge whether the sensor is operating normally; and when the sensor works normally, the comparison judging circuit is further used for comparing the second signal voltage with the second reference voltage to judge whether LNG leakage exists or not, and the process comprises the following steps:
comparing whether the first signal voltage is greater than the first reference voltage;
if yes, judging that the sensor works normally;
comparing whether the second signal voltage is larger than the second reference voltage;
if yes, judging that LNG leakage exists.
In some embodiments, the sensor signal acquisition circuit includes a first voltage dividing resistor and a second voltage dividing resistor;
the first end of the first voltage dividing resistor is connected with the first output end of the sensor, the second end of the first voltage dividing resistor is grounded, and the first end of the first voltage dividing resistor is a first signal end of the sensor signal acquisition circuit;
the first end of the second voltage dividing resistor is connected with the second output end of the sensor, the second end of the second voltage dividing resistor is grounded, and the first end of the second voltage dividing resistor is a second signal end of the sensor signal acquisition circuit.
In some embodiments, the voltage reference circuit includes a third voltage dividing resistor, a fourth voltage dividing resistor, and a fifth voltage dividing resistor;
the first end of the third voltage dividing resistor is connected with the positive electrode of the power supply, the second end of the third voltage dividing resistor is connected with the first end of the fourth voltage dividing resistor, the second end of the fourth voltage dividing resistor is connected with the first end of the fifth voltage dividing resistor, the second end of the fifth voltage dividing resistor is grounded, the common end of the third voltage dividing resistor and the fourth voltage dividing resistor is the second reference end of the voltage reference circuit, and the common end of the fourth voltage dividing resistor and the fifth voltage dividing resistor is the first reference end of the voltage reference circuit.
In some embodiments, the LNG leak detection circuit further comprises:
and the temperature compensation circuit is connected with the voltage reference circuit and is used for compensating the first reference voltage and the second reference voltage.
In some embodiments, the temperature compensation circuit includes a thermistor connected in parallel with the third voltage divider resistor.
In some embodiments, the comparison and judgment circuit comprises a first comparator, a second comparator and a controller;
the non-inverting input end of the first comparator is connected with the first signal end of the sensor signal acquisition circuit, and the inverting input end of the first comparator is connected with the first reference end of the voltage reference circuit;
the inverting input end of the second comparator is connected with the second signal end of the sensor signal acquisition circuit, and the non-inverting input end of the second comparator is connected with the second reference end of the voltage reference circuit;
the I/O interface of the controller is connected with the output end of the first comparator and the output end of the second comparator.
In some embodiments, the LNG leak detection circuit further comprises:
and the alarm circuit is connected with the comparison judging circuit, and is used for sending out alarm light when the comparison judging circuit judges that LNG leakage exists.
In a second aspect, there is provided an LNG leak detection system comprising the LNG leak detection circuit described above.
In a third aspect, there is provided an LNG commercial vehicle comprising the aforementioned LNG leak detection system.
The technical scheme provided by the invention has the beneficial effects that:
the embodiment of the invention provides an LNG leakage detection circuit, an LNG leakage detection system and an LNG commercial vehicle, wherein the LNG leakage detection circuit is provided with a sensor signal acquisition circuit, a voltage reference circuit and a comparison judging circuit, the sensor signal acquisition circuit outputs a first signal voltage and a second signal voltage according to the concentration of LNG and the working state of the sensor, the voltage reference circuit outputs the first reference voltage and the second reference voltage, the comparison judging circuit compares the first signal voltage with the first reference voltage to judge whether the sensor works normally, and when the sensor works normally, the second signal voltage is compared with the second reference voltage to judge whether LNG leakage exists. According to the invention, the working state of the sensor is judged, and when the sensor works normally, whether LNG leakage exists is judged, so that the detection result is prevented from being wrong due to the sensor fault, and the accuracy of LNG leakage detection is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic block diagram of an LNG leak detection circuit according to an embodiment of the present invention;
fig. 2 is a first circuit diagram of an LNG leak detection circuit according to an embodiment of the present invention;
fig. 3 is a second circuit diagram of an LNG leak detection circuit according to an embodiment of the present invention;
fig. 4 is a third circuit diagram of an LNG leak detection circuit according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, 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 some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The embodiment of the invention provides an LNG leakage detection circuit which can solve the technical problem that the detection result is wrong due to the fault of a sensor in the existing detection circuit.
Referring to fig. 1, an embodiment of the present invention provides an LNG leak detection circuit, including: the device comprises a sensor signal acquisition circuit, a voltage reference circuit and a comparison judging circuit.
The voltage judging circuit is connected with the sensor signal acquisition circuit and the voltage reference circuit. The sensor signal acquisition circuit is used for outputting a first signal voltage and a second signal voltage at the first signal end and the first signal end respectively according to the LNG concentration and the working state of the sensor. The voltage reference circuit is used for outputting a first reference voltage and a second reference voltage at a first reference end and a second reference end respectively. The comparison judging circuit is used for comparing the first signal voltage with the first reference voltage so as to judge whether the sensor works normally or not; and when the sensor works normally, the comparison judging circuit is also used for comparing the second signal voltage with the second reference voltage to judge whether LNG leakage exists or not.
The LNG leakage detection circuit is provided with a sensor signal acquisition circuit, a voltage reference circuit and a comparison judging circuit, wherein the sensor signal acquisition circuit outputs a first signal voltage and a second signal voltage according to the LNG concentration and the working state of the sensor, the voltage reference circuit outputs a first reference voltage and a second reference voltage, the comparison judging circuit compares the first signal voltage and the first reference voltage to judge whether the sensor works normally, and when the sensor works normally, the second signal voltage and the second reference voltage are compared to judge whether LNG leakage exists. According to the invention, the working state of the sensor is judged, and when the sensor works normally, whether LNG leakage exists is judged, so that the detection result is prevented from being wrong due to the sensor fault, and the accuracy of LNG leakage detection is improved.
As an alternative implementation manner, in an embodiment of the present invention, the comparing and judging circuit is configured to compare the first signal voltage with the first reference voltage to determine whether the sensor is operating normally, and when the sensor is operating normally, the comparing and judging circuit is further configured to compare the second signal voltage with the second reference voltage to determine whether there is LNG leakage, and the process includes:
comparing whether the first signal voltage is greater than the first reference voltage;
if yes, judging that the sensor works normally;
comparing whether the second signal voltage is larger than the second reference voltage;
if yes, judging that LNG leakage exists.
Specifically, referring to fig. 2, the sensor signal acquisition circuit includes a first voltage dividing resistor RE and a second voltage dividing resistor RL.
The first end of the first voltage dividing resistor RE is connected with the first output end of the sensor U4, the second end of the first voltage dividing resistor RE is grounded, and the first end of the first voltage dividing resistor RE is a first signal end Hlink of the sensor signal acquisition circuit and is used for outputting a first signal voltage.
The first end of the second voltage dividing resistor RL is connected with the second output end of the sensor, the second end of the second voltage dividing resistor RL is grounded, and the first end of the second voltage dividing resistor RL is a second signal end of the sensor signal acquisition circuit and is used for outputting a second signal voltage.
The sensor U4 can be a TGS2611 gas sensor, and is provided with four pins 1, 2, 3 and 4, the pins 3 and 4 of the sensor U4 are all connected with the positive electrode of a power supply, the pins 1 and 2 of the sensor U4 are a first output end and a second output end respectively, an LNG concentration sensitive resistor RS is arranged between the pins 3 and 2, the resistance value of the LNG concentration sensitive resistor RS is reduced along with the increase of the LNG concentration, and the voltage of the pin 2 of the sensor U4 is increased, namely the second signal voltage of the second signal end of the sensor signal acquisition circuit is increased. A heating resistor RH is arranged between pins 4 and 1 of the sensor U4 and is used for heating the LNG concentration sensitive resistor RS so as to enable the LNG concentration sensitive resistor RS to work normally. When the sensor U4 works normally, the heating resistor RH works normally to generate heat, and the voltage of the pin 1 of the sensor U4 is greater than 0V (usually set to be greater than 0.1V), namely the first signal voltage of the first signal end of the sensor signal acquisition circuit is greater than 0.1V; when the sensor U4 fails, the heating resistor RH is opened, the voltage of the pin 1 of the sensor U4 drops to 0V, namely the first signal voltage of the first signal end of the sensor signal acquisition circuit drops to 0V.
The voltage reference circuit comprises a third voltage dividing resistor RA, a fourth voltage dividing resistor RB and a fifth voltage dividing resistor RC;
the first end of the third voltage dividing resistor RA is connected with the positive electrode of the power supply, the second end of the third voltage dividing resistor RA is connected with the first end of the fourth voltage dividing resistor RB, the second end of the fourth voltage dividing resistor RB is connected with the first end of the fifth voltage dividing resistor RC, the second end of the fifth voltage dividing resistor RC is grounded, and the common end of the third voltage dividing resistor RA and the fourth voltage dividing resistor RB is the second reference end of the voltage reference circuit and is used for outputting a second reference voltage (set according to actual requirements). The common terminal of the fourth voltage dividing resistor RB and the fifth voltage dividing resistor RC is the first reference terminal Rlink of the voltage reference circuit, and is used for outputting a first reference voltage (typically set to 0.1V).
Referring to fig. 2 and 3, the comparison judgment circuit includes a first comparator U1, a second comparator U2, and a controller U3. The first and second comparators U1 and U2 may have a model LM2903, and the controller U3 may be an STC32F103C6T6.
The non-inverting input end of the first comparator U1 is connected with the first signal end of the sensor signal acquisition circuit, and the inverting input end of the first comparator U1 is connected with the first reference end of the voltage reference circuit.
The inverting input end of the second comparator U2 is connected with the second signal end of the sensor signal acquisition circuit, and the non-inverting input end of the second comparator U2 is connected with the second reference end of the voltage reference circuit.
The I/O interface of the controller U3 is connected to the output end of the first comparator U1 and the output end of the second comparator U2.
When the first signal voltage of the first signal end of the sensor signal acquisition circuit is greater than 0.1V, namely greater than a first reference voltage, the voltage of the non-inverting input end of the first comparator U1 is greater than the voltage of the inverting input end, the output end PRO of the first comparator U1 outputs a high level to the pin PA1 of the controller U3, and the controller U3 judges that the sensor works normally. Conversely, when the first signal voltage of the first signal end of the sensor signal acquisition circuit is 0V, that is, is smaller than the first reference voltage, the voltage of the non-inverting input end of the first comparator U1 is smaller than the voltage of the inverting input end, the output end PRO of the first comparator U1 outputs a low level to the pin PA1 of the controller U3, and the controller U3 determines that the sensor fails.
When the sensor works normally, if the concentration of the LNG increases to a certain dangerous value, the second signal voltage of the second signal end of the sensor signal acquisition circuit rises to be larger than the second reference voltage, the voltage of the inverting input end of the second comparator U2 is larger than the voltage of the non-inverting input end, the output end STA of the second comparator U2 outputs low level to the pin PA2 of the controller U3, and the controller U3 judges that LNG leakage exists.
As an alternative implementation manner, in an embodiment of the present invention, the LNG leak detection circuit further includes: and the temperature compensation circuit is connected with the voltage reference circuit and is used for compensating the first reference voltage and the second reference voltage.
Specifically, referring to fig. 2, the temperature compensation circuit includes a thermistor NTC connected in parallel with the third voltage dividing resistor RA. When the ambient temperature changes, the first reference voltage and the second reference voltage will fluctuate due to the resistance changes of the third voltage-dividing resistor RA, the fourth voltage-dividing resistor RB and the fifth voltage-dividing resistor RC, and after the ambient temperature changes, the thermistor NTC compensates the resistance changes of the third voltage-dividing resistor RA, the fourth voltage-dividing resistor RB and the fifth voltage-dividing resistor RC, so as to compensate the first reference voltage and the second reference voltage, so that the first reference voltage and the second reference voltage are in stable states at different ambient temperatures, and the accuracy of the output signals of the output ends of the first comparator U1 and the second comparator U2 is ensured.
As an alternative implementation manner, in an embodiment of the present invention, the LNG leak detection circuit further includes: and the alarm circuit is connected with the comparison judging circuit, and is used for sending out alarm light when the comparison judging circuit judges that LNG leaks.
Specifically, the alarm circuit includes a light emitting diode L1 and a control switch Q1, the control switch Q1 may be a triode, an anode of the light emitting diode L1 is connected with a positive electrode of a power supply, a cathode of the light emitting diode L1 is connected with a collector of the control switch Q1, a base of the control switch Q1 is connected with a pin 46 of the controller U3, and an emitter of the control switch Q1 is grounded, when the comparison and judgment circuit judges that LNG leaks, the pin 46 of the controller U3 outputs a high level to the base of the control switch Q1, the collector of the control switch Q1 is conducted with the emitter, and the light emitting diode L1 emits alarm light.
The embodiment of the invention provides an LNG leakage detection system, which comprises the LNG leakage detection circuit. Referring to fig. 1, the LNG leak detection circuit includes: the device comprises a sensor signal acquisition circuit, a voltage reference circuit and a comparison judging circuit.
The voltage judging circuit is connected with the sensor signal acquisition circuit and the voltage reference circuit. The sensor signal acquisition circuit is used for outputting a first signal voltage and a second signal voltage at the first signal end and the first signal end respectively according to the LNG concentration and the working state of the sensor. The voltage reference circuit is used for outputting a first reference voltage and a second reference voltage at a first reference end and a second reference end respectively. The comparison judging circuit is used for comparing the first signal voltage with the first reference voltage so as to judge whether the sensor works normally or not; and when the sensor works normally, the comparison judging circuit is also used for comparing the second signal voltage with the second reference voltage to judge whether LNG leakage exists or not.
The LNG leakage detection system comprises a sensor signal acquisition circuit, a voltage reference circuit and a comparison and judgment circuit, wherein the sensor signal acquisition circuit outputs a first signal voltage and a second signal voltage according to the LNG concentration and the working state of the sensor, the voltage reference circuit outputs a first reference voltage and a second reference voltage, the comparison and judgment circuit compares the first signal voltage with the first reference voltage to judge whether the sensor works normally, and when the sensor works normally, the second signal voltage is compared with the second reference voltage to judge whether LNG leakage exists. According to the invention, the working state of the sensor is judged, and when the sensor works normally, whether LNG leakage exists is judged, so that the detection result is prevented from being wrong due to the sensor fault, and the accuracy of LNG leakage detection is improved.
As an alternative implementation manner, in an embodiment of the present invention, the comparing and judging circuit is configured to compare the first signal voltage with the first reference voltage to determine whether the sensor is operating normally, and when the sensor is operating normally, the comparing and judging circuit is further configured to compare the second signal voltage with the second reference voltage to determine whether there is LNG leakage, and the process includes:
comparing whether the first signal voltage is greater than the first reference voltage;
if yes, judging that the sensor works normally;
comparing whether the second signal voltage is larger than the second reference voltage;
if yes, judging that LNG leakage exists.
Specifically, referring to fig. 2, the sensor signal acquisition circuit includes a first voltage dividing resistor RE and a second voltage dividing resistor RL.
The first end of the first voltage dividing resistor RE is connected with the first output end of the sensor U4, the second end of the first voltage dividing resistor RE is grounded, and the first end of the first voltage dividing resistor RE is a first signal end HLINK of the sensor signal acquisition circuit and is used for outputting a first signal voltage.
The first end of the second voltage dividing resistor RL is connected with the second output end of the sensor, the second end of the second voltage dividing resistor RL is grounded, and the first end of the second voltage dividing resistor RL is a second signal end of the sensor signal acquisition circuit and is used for outputting a second signal voltage.
The sensor U4 can be a TGS2611 gas sensor, and is provided with four pins 1, 2, 3 and 4, the pins 3 and 4 of the sensor U4 are all connected with the positive electrode of a power supply, the pins 1 and 2 of the sensor U4 are a first output end and a second output end respectively, an LNG concentration sensitive resistor RS is arranged between the pins 3 and 2, the resistance value of the LNG concentration sensitive resistor RS is reduced along with the increase of the LNG concentration, and the voltage of the pin 2 of the sensor U4 is increased, namely the second signal voltage of the second signal end of the sensor signal acquisition circuit is increased. A heating resistor RH is arranged between pins 4 and 1 of the sensor U4 and is used for heating the LNG concentration sensitive resistor RS so as to enable the LNG concentration sensitive resistor RS to work normally. When the sensor U4 works normally, the heating resistor RH works normally to generate heat, and the voltage of the pin 1 of the sensor U4 is greater than 0V (usually set to be greater than 0.1V), namely the first signal voltage of the first signal end of the sensor signal acquisition circuit is greater than 0.1V; when the sensor U4 fails, the heating resistor RH is opened, the voltage of the pin 1 of the sensor U4 drops to 0V, namely the first signal voltage of the first signal end of the sensor signal acquisition circuit drops to 0V.
The voltage reference circuit comprises a third voltage dividing resistor RA, a fourth voltage dividing resistor RB and a fifth voltage dividing resistor RC;
the first end of the third voltage dividing resistor RA is connected with the positive electrode of the power supply, the second end of the third voltage dividing resistor RA is connected with the first end of the fourth voltage dividing resistor RB, the second end of the fourth voltage dividing resistor RB is connected with the first end of the fifth voltage dividing resistor RC, the second end of the fifth voltage dividing resistor RC is grounded, and the common end of the third voltage dividing resistor RA and the fourth voltage dividing resistor RB is the second reference end of the voltage reference circuit and is used for outputting a second reference voltage (set according to actual requirements). The common terminal of the fourth voltage dividing resistor RB and the fifth voltage dividing resistor RC is the first reference terminal RLINK of the voltage reference circuit, and is used for outputting a first reference voltage (typically set to 0.1V).
Referring to fig. 2 and 3, the comparison judgment circuit includes a first comparator U1, a second comparator U2, and a controller U3. The first and second comparators U1 and U2 may have a model LM2903, and the controller U3 may be an STC32F103C6T6.
The non-inverting input end of the first comparator U1 is connected with the first signal end of the sensor signal acquisition circuit, and the inverting input end of the first comparator U1 is connected with the first reference end of the voltage reference circuit.
The inverting input end of the second comparator U2 is connected with the second signal end of the sensor signal acquisition circuit, and the non-inverting input end of the second comparator U2 is connected with the second reference end of the voltage reference circuit.
The I/O interface of the controller U3 is connected to the output end of the first comparator U1 and the output end of the second comparator U2.
When the first signal voltage of the first signal end of the sensor signal acquisition circuit is greater than 0.1V, namely greater than a first reference voltage, the voltage of the non-inverting input end of the first comparator U1 is greater than the voltage of the inverting input end, the output end PRO of the first comparator U1 outputs a high level to the pin PA1 of the controller U3, and the controller U3 judges that the sensor works normally. Conversely, when the first signal voltage of the first signal end of the sensor signal acquisition circuit is 0V, that is, is smaller than the first reference voltage, the voltage of the non-inverting input end of the first comparator U1 is smaller than the voltage of the inverting input end, the output end PRO of the first comparator U1 outputs a low level to the pin PA1 of the controller U3, and the controller U3 determines that the sensor fails.
When the sensor works normally, if the concentration of the LNG increases to a certain dangerous value, the second signal voltage of the second signal end of the sensor signal acquisition circuit rises to be larger than the second reference voltage, the voltage of the inverting input end of the second comparator U2 is larger than the voltage of the non-inverting input end, the output end STA of the second comparator U2 outputs low level to the pin PA2 of the controller U3, and the controller U3 judges that LNG leakage exists.
As an alternative implementation manner, in an embodiment of the present invention, the LNG leak detection circuit further includes: and the temperature compensation circuit is connected with the voltage reference circuit and is used for compensating the first reference voltage and the second reference voltage.
Specifically, referring to fig. 2, the temperature compensation circuit includes a thermistor NTC connected in parallel with the third voltage dividing resistor RA. When the ambient temperature changes, the first reference voltage and the second reference voltage will fluctuate due to the resistance changes of the third voltage-dividing resistor RA, the fourth voltage-dividing resistor RB and the fifth voltage-dividing resistor RC, and after the ambient temperature changes, the thermistor NTC compensates the resistance changes of the third voltage-dividing resistor RA, the fourth voltage-dividing resistor RB and the fifth voltage-dividing resistor RC, so as to compensate the first reference voltage and the second reference voltage, so that the first reference voltage and the second reference voltage are in stable states at different ambient temperatures, and the accuracy of the output signals of the output ends of the first comparator U1 and the second comparator U2 is ensured.
As an alternative implementation manner, in an embodiment of the present invention, the LNG leak detection circuit further includes: and the alarm circuit is connected with the comparison judging circuit, and is used for sending out alarm light when the comparison judging circuit judges that LNG leaks.
Specifically, the alarm circuit includes a light emitting diode L1 and a control switch Q1, the control switch Q1 may be a triode, an anode of the light emitting diode L1 is connected with a positive electrode of a power supply, a cathode of the light emitting diode L1 is connected with a collector of the control switch Q1, a base of the control switch Q1 is connected with a pin 46 of the controller U3, and an emitter of the control switch Q1 is grounded, when the comparison and judgment circuit judges that LNG leaks, the pin 46 of the controller U3 outputs a high level to the base of the control switch Q1, the collector of the control switch Q1 is conducted with the emitter, and the light emitting diode L1 emits alarm light.
The embodiment of the invention also provides an LNG commercial vehicle, which comprises the LNG leakage detection system.
In the description of the present invention, it should be noted that the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present invention. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
It should be noted that in the present invention, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is only a specific embodiment of the invention to enable those skilled in the art to understand or practice the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.
Claims (10)
1. An LNG leak detection circuit, comprising: the device comprises a sensor signal acquisition circuit, a voltage reference circuit and a comparison judging circuit;
the voltage judging circuit is connected with the sensor signal acquisition circuit and the voltage reference circuit;
the sensor signal acquisition circuit is used for outputting a first signal voltage and a second signal voltage at a first signal end and a second signal end respectively according to the LNG concentration and the working state of the sensor;
the voltage reference circuit is used for outputting a first reference voltage and a second reference voltage at a first reference end and a second reference end respectively;
the comparison judging circuit is used for comparing the first signal voltage with the first reference voltage so as to judge whether the sensor works normally or not; and when the sensor works normally, the comparison judging circuit is also used for comparing the second signal voltage with the second reference voltage so as to judge whether LNG leakage exists or not.
2. The LNG leak detection circuit as defined in claim 1, wherein the comparison and determination circuit is configured to compare the first signal voltage with the first reference voltage to determine whether the sensor is operating properly; and when the sensor works normally, the comparison judging circuit is further used for comparing the second signal voltage with the second reference voltage to judge whether LNG leakage exists or not, and the process comprises the following steps:
comparing whether the first signal voltage is greater than the first reference voltage;
if yes, judging that the sensor works normally;
comparing whether the second signal voltage is larger than the second reference voltage;
if yes, judging that LNG leakage exists.
3. The LNG leak detection circuit as defined in claim 1, wherein:
the sensor signal acquisition circuit comprises a first voltage dividing resistor and a second voltage dividing resistor;
the first end of the first voltage dividing resistor is connected with the first output end of the sensor, the second end of the first voltage dividing resistor is grounded, and the first end of the first voltage dividing resistor is a first signal end of the sensor signal acquisition circuit;
the first end of the second voltage dividing resistor is connected with the second output end of the sensor, the second end of the second voltage dividing resistor is grounded, and the first end of the second voltage dividing resistor is a second signal end of the sensor signal acquisition circuit.
4. The LNG leak detection circuit as defined in claim 1, wherein:
the voltage reference circuit comprises a third voltage dividing resistor, a fourth voltage dividing resistor and a fifth voltage dividing resistor;
the first end of the third voltage dividing resistor is connected with the positive electrode of the power supply, the second end of the third voltage dividing resistor is connected with the first end of the fourth voltage dividing resistor, the second end of the fourth voltage dividing resistor is connected with the first end of the fifth voltage dividing resistor, the second end of the fifth voltage dividing resistor is grounded, the common end of the third voltage dividing resistor and the fourth voltage dividing resistor is the second reference end of the voltage reference circuit, and the common end of the fourth voltage dividing resistor and the fifth voltage dividing resistor is the first reference end of the voltage reference circuit.
5. The LNG leak detection circuit as defined in claim 4, further comprising:
and the temperature compensation circuit is connected with the voltage reference circuit and is used for compensating the first reference voltage and the second reference voltage.
6. The LNG leak detection circuit as defined in claim 5, wherein:
the temperature compensation circuit comprises a thermistor, and the thermistor is connected with the third voltage dividing resistor in parallel.
7. The LNG leak detection circuit as defined in claim 1, wherein:
the comparison and judgment circuit comprises a first comparator, a second comparator and a controller;
the non-inverting input end of the first comparator is connected with the first signal end of the sensor signal acquisition circuit, and the inverting input end of the first comparator is connected with the first reference end of the voltage reference circuit;
the inverting input end of the second comparator is connected with the second signal end of the sensor signal acquisition circuit, and the non-inverting input end of the second comparator is connected with the second reference end of the voltage reference circuit;
the I/O interface of the controller is connected with the output end of the first comparator and the output end of the second comparator.
8. The LNG leak detection circuit as defined in claim 1, further comprising:
and the alarm circuit is connected with the comparison judging circuit, and is used for sending out alarm light when the comparison judging circuit judges that LNG leakage exists.
9. An LNG leak detection system comprising the LNG leak detection circuit of any one of claims 1 to 8.
10. An LNG commercial vehicle comprising the LNG leak detection system of claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211352470.5A CN116147852A (en) | 2022-10-31 | 2022-10-31 | LNG leakage detection circuit, system and LNG commercial vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211352470.5A CN116147852A (en) | 2022-10-31 | 2022-10-31 | LNG leakage detection circuit, system and LNG commercial vehicle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116147852A true CN116147852A (en) | 2023-05-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211352470.5A Pending CN116147852A (en) | 2022-10-31 | 2022-10-31 | LNG leakage detection circuit, system and LNG commercial vehicle |
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| Country | Link |
|---|---|
| CN (1) | CN116147852A (en) |
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2022
- 2022-10-31 CN CN202211352470.5A patent/CN116147852A/en active Pending
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