CN112555000A - Liquid level sensor monitoring method for vehicle, vehicle SCR system and control unit - Google Patents
Liquid level sensor monitoring method for vehicle, vehicle SCR system and control unit Download PDFInfo
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- CN112555000A CN112555000A CN201910915483.0A CN201910915483A CN112555000A CN 112555000 A CN112555000 A CN 112555000A CN 201910915483 A CN201910915483 A CN 201910915483A CN 112555000 A CN112555000 A CN 112555000A
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- level sensor
- heater
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- liquid
- monitored
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- 239000007788 liquid Substances 0.000 title claims abstract description 133
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000012544 monitoring process Methods 0.000 title claims abstract description 17
- 238000010438 heat treatment Methods 0.000 claims abstract description 25
- 230000002159 abnormal effect Effects 0.000 claims abstract description 6
- 230000007257 malfunction Effects 0.000 claims abstract description 6
- 238000001514 detection method Methods 0.000 claims description 12
- 239000012530 fluid Substances 0.000 claims description 7
- 230000007423 decrease Effects 0.000 description 7
- 238000012545 processing Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910001868 water Inorganic materials 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
- F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
-
- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
-
- 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
- Y02T10/12—Improving ICE efficiencies
-
- 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
- Y02T10/40—Engine management systems
Abstract
A technique of monitoring a level sensor in a vehicle liquid tank, wherein: monitoring the working state of the liquid level sensor; when the abnormal work of the liquid level sensor is monitored, a heater in the liquid tank is started or maintained to heat the liquid in the liquid tank, and the heating state of the heater is monitored; performing liquid tank drainage operation under the condition that the heater is monitored to be heated stably; in the case of monitoring the heater to heat unstably, carrying out liquid tank charging operation; the operating state of the level sensor is then monitored, and a level sensor malfunction is determined when abnormal operation of the level sensor is monitored.
Description
Technical Field
The present application relates to a technique for monitoring a level sensor, in particular of the ultrasonic type, in a vehicle tank, in particular in an exhaust gas treatment tank.
Background
SCR (selective catalytic reduction) systems are used to reduce the NOx content of diesel exhaust. In the SCR system, a reducing agent, generally called an exhaust gas treatment liquid, is injected into exhaust gas to reduce NOx in the exhaust gas into harmless components such as nitrogen, water, and carbon dioxide by a selective catalytic reduction method. The SCR system generally includes a tank containing an exhaust gas treatment liquid, a metering unit for injecting the treatment liquid into an exhaust pipe of the diesel engine, and a pump unit which draws the treatment liquid from the tank and supplies it under pressure to the metering unit. An ultrasonic liquid level sensor is arranged in the liquid tank and used for detecting the liquid level in the liquid tank. Such level sensors achieve level measurement by means of the interface between the process liquid and the air above. When the liquid tank is excessively filled with the processing liquid, air in the liquid tank is completely squeezed out, an interface between the processing liquid and the air does not exist, and the liquid level sensor cannot detect the liquid level and can be misdiagnosed as a sensor fault. When the process fluid in the tank is substantially drained, the level sensor may also fail to detect the fluid level and may be misdiagnosed as a sensor fault. The user may go to a maintenance station to replace the level sensor or even the entire tank.
Disclosure of Invention
In view of the above-described problems, the present application aims to provide a technique of monitoring a level sensor, in particular an ultrasonic type level sensor, in a vehicle tank, in particular in a process tank, avoiding the level sensor being misdiagnosed.
According to one aspect of the present application, there is provided a method of monitoring a level sensor in a vehicle fluid tank, comprising the steps of:
monitoring the working state of the liquid level sensor;
when the abnormal work of the liquid level sensor is monitored, a heater in the liquid tank is started or maintained to heat the liquid in the liquid tank, and the heating state of the heater is monitored;
performing liquid tank drainage operation under the condition that the heater is monitored to be heated stably; in the case of monitoring the heater to heat unstably, carrying out liquid tank charging operation;
the operating state of the level sensor is then monitored, and a level sensor malfunction is determined when abnormal operation of the level sensor is monitored.
According to another aspect of the present application, a control unit of a vehicle SCR system is provided, which is configured to control the operation of a tank, a pump unit and a dosing unit of the SCR system, and is configured to monitor a malfunction of a liquid level sensor in the tank by means of the method of the present application.
According to another aspect of the present application, a vehicle SCR system is provided, comprising a tank, a pump unit, a dosing unit and the control unit of the present application.
According to the method and the device, whether the liquid tank is excessively filled or emptied is confirmed through the operation of related elements of the liquid tank under the condition that the liquid level sensor does not have a sensing signal, so that whether the liquid level sensor breaks down or not is judged, and misdiagnosis of the liquid level sensor is avoided.
Drawings
FIG. 1 is a schematic illustration of an SCR system according to one possible embodiment of the present application;
FIG. 2 is a flow chart of an ultrasonic type level sensor monitoring method according to one possible embodiment of the present application.
Detailed Description
Fig. 1 shows an exhaust SCR system for use in a vehicle, in particular a diesel vehicle, according to an embodiment of the present application, associated with an exhaust pipe (not shown) of the vehicle engine for injecting an exhaust treatment fluid, typically an aqueous urea solution, into the exhaust pipe for reducing the NOx content of the exhaust gases. The SCR system mainly comprises a liquid tank 1, a pump unit 2 and a metering unit 3. The liquid tank 1 is for containing a treatment liquid. The pump unit 2 includes therein a supply pump 4 and a return pump 5, wherein the supply pump 4 draws and pressurizes the treatment liquid from the liquid tank 1 through a suction line L1 and supplies it to the metering unit 3 through a supply line L2 when the engine is operated. The metering unit 3 is used to inject the treatment liquid into the exhaust pipe in a metered manner. After the engine stops operating, the suck-back pump 5 pumps the treatment liquid in the pump unit 2 and the metering unit 3 back to the liquid tank 1 through the suck-back line L3 in order to prevent the treatment liquid from depositing, crystallizing, etc. in the pump unit 2 and the metering unit 3 after the engine operation is finished.
A liquid level sensor 6 is arranged in the liquid tank 1 and used for detecting the liquid level of the treatment liquid in the liquid tank 1; a filter 7 connected to an upstream end of the suction line L1 for filtering impurities in the processing liquid; and a heater 8 for heating the treatment liquid.
Furthermore, the SCR system comprises a control unit 10, which is connected to the tank 1, the pump unit 2 and the dosing unit 3 as well as to other functional elements of the SCR system for controlling their operation and monitoring their status.
A level sensor 6 is mounted at the bottom of the tank 1. According to one embodiment, the level sensor 6 is of the ultrasonic type, the level measurement being achieved by emitting ultrasonic waves to the interface between the treatment liquid in the tank 1 and the air above and receiving the ultrasonic waves reflected by this interface. When the liquid level sensor 6 fails, the liquid level is not detected. Further, when the liquid tank 1 is excessively filled with the treatment liquid, the air in the liquid tank 1 is substantially entirely pushed out, so that there is no interface between the treatment liquid and the air, no ultrasonic wave is reflected back to the liquid level sensor 6, and the liquid level sensor 6 does not detect the liquid level. Furthermore, when the treatment liquid in the liquid tank 1 is excessively consumed without timely replenishment of the treatment liquid, the liquid level may fall below the ultrasonic wave emitting portion of the liquid level sensor 6 and even be substantially empty, and the liquid level sensor 6 will not detect the liquid level.
The control unit 10 of this application can judge that level sensor 6 breaks down when level sensor 6 can not detect the liquid level, still the fluid reservoir 1 is by excessive filling to avoid level sensor 6 to be diagnosed by the mistake.
When the control unit 10 detects whether the liquid level sensor 6 is malfunctioning, it is necessary to operate by means of the heater 8. Specifically, the heater 8 is different in operating state between the presence and absence of the treatment liquid therearound, and particularly has different temperature rise rates, operating currents, and the like. For example, when the treatment liquid is present around the heater 8, the temperature increase rate of the heater 8 is slow (steady heating), and when the treatment liquid is not present around the heater 8, the temperature increase rate of the heater 8 is rapidly increased (non-steady heating).
As a possible embodiment, the heater 8 is a PTC (positive temperature coefficient) heater, the heating element of which is made of a PTC material, the resistance of which increases with temperature. With this material, when the processing liquid is raised to a certain temperature, the resistance of the heating element is raised and the current is reduced, so that the power of the heater 8 is reduced, thereby preventing the processing liquid from being excessively heated, and therefore the heater 8 has a self-temperature-limiting function. When the treatment liquid is not present around the heater 8, the temperature rise rate of the PTC heater 8 is very fast, and the operating current rapidly decreases.
The control unit 10 determines the charging condition in the liquid tank 1 according to the operating state of the heater 8. For this reason, the heater 8 is preferably disposed at substantially the same level as or lower than the ultrasonic wave emitting portion of the level sensor 6. For example, the heater 8 is installed at or near the bottom of the tank 1.
The control unit 10 activates the heater 8 or maintains the heating state of the heater 8 when it finds that the liquid level sensor 6 does not detect a signal within a certain time period Δ T (for example, about 5 minutes), and monitors the heating state of the heater 8 for judging the state of the liquid in the tank 1. Specifically, in the case where the control unit 10 detects that the heater 8 is stably heated, it may be determined that a sufficient amount of the processing liquid is present in the liquid tank, and in the case where the heater is not stably heated, it may be determined that the amount of the processing liquid in the liquid tank is insufficient. For example, in a condition where the heater 8 is stably heated, the heater 8 is normally warmed up, thereby determining that the treatment liquid level in the liquid tank 1 is located above the ultrasonic wave emitting portion of the level sensor 6 (may be referred to as a first level condition), whereas in a condition where the heater 8 is not stably heated, the heater 8 is excessively warmed up, thereby determining that the treatment liquid in the liquid tank 1 has fallen below the ultrasonic wave emitting portion of the level sensor 6 (close to emptying or even already emptied, may be referred to as a second level condition). In the case where the heater 8 is a PTC heater, the control unit 10 detects the operating current of the heater 8, and if the falling rate of the operating current is normal, it is determined that the heater 8 is stably heating, and it is determined that the level of the treatment liquid in the liquid tank 1 is above the ultrasonic wave emitting portion of the liquid level sensor 6 (first liquid level condition), and in the case where it is detected that the falling rate of the operating current of the heater 8 is too fast or becomes lower than a predetermined minimum current value, it is determined that the heater 8 is not stably heating, and it is determined that the treatment liquid in the liquid tank 1 falls below the ultrasonic wave emitting portion of the liquid level sensor 6 (second liquid level condition).
Next, in the case where the control unit 10 determines that the first liquid level condition is such that sufficient treatment liquid is present in the tank 1 to cover the ultrasonic wave emitting portion of the liquid level sensor 6, the control unit 10 controls the pump unit 2 and the metering unit 3 to operate for a period of time to spray a predetermined dose of treatment liquid which ensures that the liquid level in the tank 1 falls to a level which produces a treatment liquid-air interface sufficient for detection by the liquid level sensor 6. For example, the dose may be determined as the minimum dose that is able to ensure that the level of liquid from when the tank 1 is completely full drops sufficiently to create a treatment liquid-air interface that can be detected by the level sensor 6. For the tank 1 having the automatic filling function, the control unit 10 prevents the tank 1 from being filled while the pump unit 2 and the metering unit 3 are operating. After the pump unit 2 and the metering unit 3 are operated for the period of time, the control unit 10 detects the state of the liquid level sensor 6, and if the liquid level sensor 6 has a detection signal, the liquid level sensor 6 is determined to be normal; if the level sensor 6 still does not detect a signal for a certain period of time Δ T1 (e.g., about 5 minutes, which may or may not be equal to Δ T), then it is determined that the level sensor 6 is malfunctioning and the control unit 10 may trigger a warning element to alert the user that the level sensor 6 is malfunctioning and needs to be replaced (for an integrated tank 1, the entire tank 1 needs to be replaced).
In the case where the control unit 10 determines the second level condition, i.e. the treatment liquid in the tank 1 has fallen below the ultrasonic emission site of the level sensor 6, the control unit 10 may switch off the heater 8 and initiate the charging operation of the tank 1. When the SCR system does not have the function of automatically filling the tank 1, the control unit 10 may trigger an alarm element to remind the user to replenish the tank 1 with the treatment liquid. The tank 1 is filled with a dose that ensures that a treatment liquid-air interface is created in the tank 1 that is sufficient for detection by the level sensor 6, e.g., the dose is determined to be a minimum dose sufficient to create a treatment liquid-air interface detectable by the level sensor 6 from a state in which the tank 1 is fully empty, or nearly empty. Then, the control unit 10 detects the state of the liquid level sensor 6, and if the liquid level sensor 6 has a detection signal, it is determined that the liquid level sensor 6 is normal; if the level sensor 6 still does not detect a signal for a certain period of time Δ T2 (e.g., about 5 minutes, which may or may not be equal to Δ T and Δ T1), then it is determined that the level sensor 6 is malfunctioning, and the control unit 10 may alert the user that the level sensor 6 is malfunctioning.
It will be appreciated that various modifications may be made by those skilled in the art to the structure and function of the SCR system, and in particular the control unit 10, described hereinbefore within the scope of the present application.
The present application also relates to a monitoring method of an ultrasonic type level sensor in a process tank, which method can optionally be applied in the SCR system described above and can be implemented by means of the control unit 10 described above. One possible flow of the method is shown schematically in fig. 2.
As shown in fig. 2, in step S1, the operating state of the ultrasonic type level sensor in the liquid tank is monitored.
Next, at step S2, it is determined that the level sensor has not detected a signal for a certain period of time (e.g., about 5 minutes).
Next, in step S3, the heater in the liquid tank is activated or the heating state of the heater is maintained, and the operating state of the heater is monitored.
Next, in step S4, it is determined whether the heating state of the heater is in steady heating. For example, the determination is made by whether the temperature rise rate of the heater exceeds a predetermined temperature rise rate, whether the operating current decrease rate of the heater exceeds a predetermined current decrease rate, or whether the operating current value of the heater is lower than a predetermined minimum current value.
If it is judged in step S4 that the operating state of the heater is in the steady heating (for example, the temperature increase speed does not exceed the predetermined temperature increase speed, the operating current decrease speed does not exceed the predetermined current decrease speed, or the operating current value of the heater is not lower than the predetermined minimum current value), it goes to step S5.
At step S5, the process fluid in the tank is caused to be output by a predetermined amount (for an automatic fill type tank, the tank is prevented from filling) to an amount sufficient to create a process fluid-air interface in the tank required for level sensor detection. Next, in step S7, the operation state of the level sensor is monitored, and if the level sensor has a detection signal, it is determined in step S8 that the level sensor is normal, and if the level sensor has no detection signal for a certain period of time (e.g., about 5 minutes), it is determined in step S9 that the level sensor is malfunctioning.
On the other hand, if it is judged in step S4 that the operating state of the heater is in non-steady heating (for example, the temperature increase speed exceeds the predetermined temperature increase speed, the operating current decrease speed exceeds the predetermined current decrease speed, or the operating current value of the heater is lower than the predetermined minimum current value), it goes to step S6.
At step S6, the tank is filled (automatically or manually) to an amount sufficient to create a process fluid-air interface in the tank that is required for level sensor detection. In step S6, the heater may be turned off. Next, the operation of the level sensor is monitored in step S7, and if the level sensor has a detection signal, the operation proceeds to step S8, and if the level sensor has no detection signal for a certain period of time (for example, about 5 minutes), the operation proceeds to step S9.
It is noted that the foregoing describes an SCR system for a vehicle engine, a control unit thereof and a related method, which are capable of monitoring an ultrasonic type level sensor in a process liquid tank. However, the techniques of this application may be used to monitor various types of level sensors in other liquid tanks in a vehicle. Accordingly, the scope of the present application covers various occasions where a level sensor malfunction is determined based on the operating state of a heater in a vehicle liquid tank.
Although the present application has been described herein with reference to particular embodiments, the scope of the present application is not intended to be limited to the details shown. Various modifications may be made to these details without departing from the underlying principles of the application.
Claims (11)
1. A method of monitoring a level sensor in a vehicle fluid tank, comprising the steps of:
monitoring the working state of the liquid level sensor;
when the abnormal work of the liquid level sensor is monitored, a heater in the liquid tank is started or maintained to heat the liquid in the liquid tank, and the heating state of the heater is monitored;
performing liquid tank drainage operation under the condition that the heater is monitored to be heated stably; in the case of monitoring the heater to heat unstably, carrying out liquid tank charging operation;
the operating state of the level sensor is then monitored, and a level sensor malfunction is determined when abnormal operation of the level sensor is monitored.
2. The method of claim 1, wherein the tank is an exhaust treatment tank in a vehicle SCR system, the liquid in the tank is an exhaust treatment liquid, and the level sensor is an ultrasonic level sensor.
3. The method of claim 2, wherein the heater is disposed at a position substantially level with or below an ultrasonic emission site of the level sensor.
4. A method according to any one of claims 1 to 3, wherein the heating state of the heater is monitored based on the heating temperature of the heater, and the heater is determined to be in an unstable heating state when the rate of rise of the heating temperature exceeds a predetermined temperature rise rate value, and/or when the heating temperature exceeds a predetermined temperature value.
5. A method according to any one of claims 1 to 3, wherein the heating state of the heater is monitored based on a change in the operating current of the heater, and the heater is determined to be in an unstable heating state when the rate of change in the operating current exceeds a predetermined current change rate value, or when the operating current reaches a predetermined limit current value.
6. A method according to any one of claims 1 to 3 wherein the heater is a PTC heater and is determined to be in an unstable heating state when the operating current of the heater is below a predetermined minimum current value.
7. The method according to any one of claims 1 to 6, wherein the amount of liquid drainage in the tank draining operation is set to be equal to or greater than a minimum amount of liquid drainage required for the liquid level in the tank to fall to a level suitable for detection by the liquid level sensor;
the amount of charge in the tank charging operation is set to be equal to or greater than the minimum amount of charge required to raise the liquid level in the tank to a level suitable for detection by the level sensor.
8. A method as claimed in any one of claims 1 to 7, wherein the heater is switched off during a tank charging operation.
9. The method of any one of claims 1 to 8, wherein the sensor is determined to be operating improperly when the sensor does not detect a signal for a predetermined period of time.
10. A control unit (10) of a vehicle SCR system, which is configured to control the operation of a tank (1), a pump unit (2) and a dosing unit (3) of the SCR system and is configured to monitor a malfunction of a liquid level sensor (6) in the tank (1) by means of a method according to any one of claims 1 to 9.
11. A vehicle SCR system comprising a tank (1), a pump unit (2) and a dosing unit (3), and a control unit (10) according to claim 10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910915483.0A CN112555000B (en) | 2019-09-26 | Liquid level sensor monitoring method for vehicle, vehicle SCR system and control unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910915483.0A CN112555000B (en) | 2019-09-26 | Liquid level sensor monitoring method for vehicle, vehicle SCR system and control unit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112555000A true CN112555000A (en) | 2021-03-26 |
| CN112555000B CN112555000B (en) | 2024-05-14 |
Family
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Citations (7)
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|---|---|---|---|---|
| US5741958A (en) * | 1995-12-23 | 1998-04-21 | Robert Bosch Gmbh | Method for detecting and documenting exhaust-gas relevant malfunctions of a motor vehicle having an internal combustion engine with the aid of on-board means |
| JP2002031563A (en) * | 2000-07-14 | 2002-01-31 | Yamatake Corp | Liquid level detection device, liquid supply control device and liquid delivery system |
| CN101281053A (en) * | 2007-04-03 | 2008-10-08 | 通用汽车环球科技运作公司 | System for detecting failures in fuel systems |
| JP2015021452A (en) * | 2013-07-22 | 2015-02-02 | トヨタ自動車株式会社 | Diagnosis device of fuel level sensor |
| US20160258377A1 (en) * | 2015-03-04 | 2016-09-08 | Denso Corporation | Fuel level sensor diagnosis device |
| WO2018055128A1 (en) * | 2016-09-22 | 2018-03-29 | Plastic Omnium Advanced Innovation And Research | Method and system for determining a quantity of liquid in a tank |
| CN107923279A (en) * | 2015-08-14 | 2018-04-17 | 康明斯排放处理公司 | Virtual restoration agent liquid level sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5741958A (en) * | 1995-12-23 | 1998-04-21 | Robert Bosch Gmbh | Method for detecting and documenting exhaust-gas relevant malfunctions of a motor vehicle having an internal combustion engine with the aid of on-board means |
| JP2002031563A (en) * | 2000-07-14 | 2002-01-31 | Yamatake Corp | Liquid level detection device, liquid supply control device and liquid delivery system |
| CN101281053A (en) * | 2007-04-03 | 2008-10-08 | 通用汽车环球科技运作公司 | System for detecting failures in fuel systems |
| JP2015021452A (en) * | 2013-07-22 | 2015-02-02 | トヨタ自動車株式会社 | Diagnosis device of fuel level sensor |
| US20160258377A1 (en) * | 2015-03-04 | 2016-09-08 | Denso Corporation | Fuel level sensor diagnosis device |
| CN107923279A (en) * | 2015-08-14 | 2018-04-17 | 康明斯排放处理公司 | Virtual restoration agent liquid level sensor |
| WO2018055128A1 (en) * | 2016-09-22 | 2018-03-29 | Plastic Omnium Advanced Innovation And Research | Method and system for determining a quantity of liquid in a tank |
| CN109844465A (en) * | 2016-09-22 | 2019-06-04 | 全耐塑料高级创新研究公司 | Method and system for determining the amount of liquid in a tank |
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