CN110552770A - Mixer crystallization detection method and system - Google Patents
Mixer crystallization detection method and system Download PDFInfo
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- CN110552770A CN110552770A CN201910880612.7A CN201910880612A CN110552770A CN 110552770 A CN110552770 A CN 110552770A CN 201910880612 A CN201910880612 A CN 201910880612A CN 110552770 A CN110552770 A CN 110552770A
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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
- F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
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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
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/08—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a pressure sensor
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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
- 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
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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
- Y02T10/40—Engine management systems
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- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
the invention discloses a mixer crystallization detection method and a mixer crystallization detection system. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
Description
Technical Field
The invention relates to the technical field of SCR (selective catalytic reduction), in particular to a mixer crystallization detection method and system.
background
diesel engines have significant advantages over gasoline engines in terms of power, economy and reliability, particularly with respect to very low CO 2 emissions, and their use has gradually expanded to all types of vehicles, however, Diesel engines have significant emissions of nitrogen oxides (NO X). as emissions escalate, emissions become the standard for engines, particularly in the sixth and off-road four stages, aftertreatment assemblies including DOC (Oxidation Catalyst), SCR (Selective Catalytic Reduction), DPF (Diesel particulate filter), and ASC (ammonia slip Catalyst).
in the current emission stage, the requirement on tail gas NOx is low, and particularly, an efficient SCR technical route engine has a high risk of mixer crystallization due to the large urea injection amount. When the mixer is more severely crystallized, the power of the engine is insufficient. Often users find that the mixer is substantially blocked by crystals, in which case the post-treatment needs to be replaced.
in order to find the mixer crystallization as early as possible so as to solve the problem in time, the detection scheme of the mixer crystallization at present is as follows: in the first variant, mixer crystallization is determined when a drop in engine power is detected and is treated accordingly. In the second scheme, the mixer crystallization treatment is carried out every certain mileage of the engine. However, as the engine usage time increases, the performance of various aspects of the engine, including engine power, may suffer from certain degradation, and therefore there is a large error in using the engine power drop or each certain mileage the engine runs as a trigger condition for triggering the mixer crystallization process.
Disclosure of Invention
in view of the above, the present invention discloses a mixer crystallization detection method and system, which compare an obtained SCR upstream pressure value with an SCR upstream pressure threshold value to determine whether to process a mixer crystallization, and determine to process the mixer crystallization when the SCR upstream pressure value is not less than the SCR upstream pressure threshold value.
A mixer crystallization detection method, comprising:
Acquiring the pressure value of the selective catalytic reduction SCR upstream of the engine in the running process of the vehicle;
Judging whether the SCR upstream pressure value is not less than an SCR upstream pressure threshold value, wherein the SCR upstream pressure threshold value is as follows: when the urea crystallization volume in the mixer calibrated by the engine pedestal is the maximum crystallization volume value, the exhaust gas flow rate corresponds to the SCR upstream pressure value corresponding to the SCR upstream temperature;
and if the SCR upstream pressure value is not less than the SCR upstream pressure threshold value, outputting prompt information, wherein the prompt information is used for indicating that the mixer crystallization needs to be treated.
optionally, the calibration process of the SCR upstream pressure threshold is as follows:
and crystallizing the mixer by adopting a rapid crystallization method, calibrating the SCR upstream pressure based on the engine exhaust gas flow and the SCR upstream temperature by taking the crystallization amount when the engine performance is degraded as a reference when the crystallization amount causes the degradation of the engine performance, and determining the calibrated SCR upstream pressure as the SCR upstream pressure threshold.
Optionally, if the SCR upstream pressure value is not less than the SCR upstream pressure threshold, outputting a prompt message, specifically including:
judging whether the continuous times that the SCR upstream pressure value is not less than the SCR upstream pressure threshold value reach preset times or not;
if yes, outputting the prompt message.
Optionally, after the outputting the prompt information, the method further includes:
Receiving a mixer crystallization processing instruction;
based on the mixer crystallization processing instruction, the rotating speed and the torque of the engine are adjusted, fuel oil is injected after the engine is started, mixer crystallization is processed, and the mixer crystallization is calibrated through PID control, so that the temperature of the DPF upstream rises in a stepped mode according to a preset temperature interval until the temperature of the DPF upstream of the diesel particulate filter reaches the preset temperature, and the stable operation time of the engine reaches the preset time.
Optionally, the preset temperature is 600 ℃, and the preset time is 10 min.
Optionally, after adjusting the rotation speed and the torque of the engine based on the mixer crystallization processing instruction, and starting the post-injection fuel oil, processing the mixer crystallization until the upstream temperature of the DPF reaches a preset temperature and the steady operation time of the engine reaches a preset time, the method further includes:
Acquiring the SCR upstream pressure value again;
Judging whether the SCR upstream pressure value obtained again is not less than the SCR upstream pressure threshold value;
If so, the mixer is determined to be fully crystallized.
A mixer crystallization detection system comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring the pressure value of the selective catalytic reduction SCR upstream of an engine in the running process of a vehicle;
the first judging unit is used for judging whether the SCR upstream pressure value is not less than an SCR upstream pressure threshold value, wherein the SCR upstream pressure threshold value is as follows: when the urea crystallization volume in the mixer calibrated by the engine pedestal is the maximum crystallization volume value, the exhaust gas flow rate corresponds to the SCR upstream pressure value corresponding to the SCR upstream temperature;
and the output unit is used for outputting prompt information under the condition that the first judgment unit judges that the crystals of the mixer need to be processed.
Optionally, the output unit specifically includes:
the judging subunit is used for judging whether the continuous times that the SCR upstream pressure value is not less than the SCR upstream pressure threshold value reach preset times or not;
And the output subunit is used for outputting the prompt information under the condition that the judgment subunit judges that the prompt information is positive.
optionally, the method further includes:
A receiving unit, configured to receive a mixer crystallization processing instruction after the output unit outputs the prompt information or the output subunit outputs the prompt information;
And the adjusting unit is used for adjusting the rotating speed and the torque of the engine based on the mixer crystallization processing instruction, starting the post-injection fuel oil, processing the mixer crystallization, calibrating through PID control, and enabling the DPF upstream temperature to rise in a stepped manner according to a preset temperature interval until the DPF upstream temperature of the diesel particulate filter reaches the preset temperature and the stable operation time of the engine reaches the preset time.
optionally, the preset temperature is 600 ℃, and the preset time is 10 min.
Optionally, the method further includes:
the re-acquisition unit is used for adjusting the rotating speed and the torque of the engine based on the mixer crystallization processing instruction, starting the post-injection fuel oil, processing mixer crystallization until the upstream temperature of the DPF of the diesel particulate filter reaches a preset temperature and the stable operation time of the engine reaches a preset time, and then acquiring the upstream pressure value of the SCR again;
The second judgment unit is used for judging whether the SCR upstream pressure value acquired again is not less than the SCR upstream pressure threshold value;
a determination unit configured to determine that the mixer is completely crystallized if the second determination unit determines yes.
according to the technical scheme, whether the mixer crystal is processed or not is determined by comparing the SCR upstream pressure value obtained in the running process of the vehicle with the SCR upstream pressure threshold, and when the SCR upstream pressure value is not smaller than the SCR upstream pressure threshold, the mixer crystal is determined to be processed. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the disclosed drawings without creative efforts.
FIG. 1 is a flow chart of a mixer crystallization detection method according to an embodiment of the present invention;
FIG. 2 is a flow chart of another mixer crystallization detection method disclosed in an embodiment of the present invention;
FIG. 3 is a flow chart of another mixer crystallization detection method disclosed in an embodiment of the present invention;
FIG. 4 is a graph showing a temperature of an upstream side of a DPF increasing in steps according to a predetermined temperature interval according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a mixer crystallization detection system according to an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of another mixer crystallization detection system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention discloses a mixer crystallization detection method and a mixer crystallization detection system. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
referring to fig. 1, a flow chart of a mixer crystallization detection method according to an embodiment of the present invention is disclosed, the method includes the steps of:
Step S101, acquiring an SCR upstream pressure value of an engine in the running process of a vehicle;
It should be noted that the mixer crystallization detection method disclosed in the present invention is applicable to a vehicle equipped with an SCR (Selective Catalytic Reduction) tank.
SCR tank, a selective catalytic reduction device, means a device installed in an engine exhaust to reduce NO x in engine exhaust to N 2 and H 2 O by means of a reductant (NH 3), thereby reducing NO x in engine exhaust.
the embodiment obtains the SCR upstream pressure value of the engine through an SCR upstream pressure sensor of the engine.
Step S102, judging whether the SCR upstream pressure value is not less than the SCR upstream pressure threshold value, if so, executing step S103;
the SCR upstream pressure threshold value is an SCR upstream pressure value corresponding to the SCR upstream temperature and the exhaust gas flow when the urea crystallization volume in a mixer calibrated by an engine bench is the maximum crystallization volume limit value a g/cm 3.
specifically, the calibration process of the pressure threshold value upstream of the SCR is as follows:
and crystallizing the mixer by adopting a rapid crystallization method, calibrating the SCR upstream pressure Map1 based on the engine exhaust gas flow and the SCR upstream temperature by taking the crystallization amount when the engine performance is degraded as a reference when the crystallization amount causes the degradation of the engine performance, and determining the SCR upstream pressure Map1 as an SCR upstream pressure threshold value.
it should be noted that, the SCR upstream Pressure MAP (intake pipe Pressure Sensor) is an SCR upstream Pressure value, where the urea crystal volume in a mixer calibrated by an engine bench is 0g/cm 3 and a g/cm 3 (theoretically acceptable maximum crystal volume limit value which does not affect various performances of the engine and causes the crystal volume when the engine power is reduced by 3%), and b g/cm 3 (too much crystal volume causes post-treatment blockage and can be solved only by replacing a post-treatment tank) where the exhaust gas flow rate corresponds to the SCR upstream temperature.
when the value of the pressure upstream of the SCR is less than the SCR upstream pressure threshold value, crystallization on the mixer is less, and the crystallization treatment is not needed.
And S103, outputting prompt information, wherein the prompt information is used for indicating that the mixer crystals need to be processed.
in this embodiment, when it is determined that the detected SCR upstream pressure value is not less than the SCR upstream pressure threshold value, a prompt message is output, for example, an indicator lamp of a cab is controlled to be turned on, so that a driver knows that the mixer crystal needs to be processed.
In practical applications, the prompt message may be in other forms, such as a voice prompt, and the present invention is not limited herein.
in summary, the mixer crystallization detection method disclosed by the invention determines whether to process the mixer crystallization by comparing the SCR upstream pressure value obtained during the vehicle running process with the SCR upstream pressure threshold value, and determines to process the mixer crystallization when the SCR upstream pressure value is not less than the SCR upstream pressure threshold value. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
in order to avoid misjudgment of the trigger of the active treatment strategy of the mixer crystallization caused by the error of the detection of the pressure value at the upstream of the SCR, the invention further improves the embodiment.
Referring to fig. 2, a flow chart of a mixer crystallization detection method according to another embodiment of the present invention is disclosed, the method including the steps of:
Step S201, acquiring an SCR upstream pressure value of an engine in the running process of a vehicle;
Step S202, judging whether the SCR upstream pressure value is not less than an SCR upstream pressure threshold value, if so, executing step S203;
it should be noted that step S201 and step S202 correspond to step S101 and step S102 in the embodiment shown in fig. 1, respectively, and therefore, specific operation principles of step S201 and step S202 are not described herein again.
Step S203, judging whether the continuous times that the SCR upstream pressure value is not less than the SCR upstream pressure threshold value reach a preset time, if so, executing step S204, and if not, returning to execute step S201;
And step S204, outputting prompt information, wherein the prompt information is used for indicating that the mixer crystals need to be processed.
in this embodiment, when it is determined that the detected SCR upstream pressure value is not less than the SCR upstream pressure threshold value, a prompt message is output, for example, an indicator lamp of a cab is controlled to be turned on, so that a driver knows that the mixer crystal needs to be processed.
In practical applications, the prompt message may be in other forms, such as a voice prompt, and the present invention is not limited herein.
in summary, the mixer crystallization detection method disclosed by the invention determines whether to process the mixer crystallization by comparing the SCR upstream pressure value obtained in the vehicle running process with the SCR upstream pressure threshold, and determines to process the mixer crystallization when the SCR upstream pressure value is not less than the SCR upstream pressure threshold and the SCR upstream pressure value detected continuously for many times is not less than the SCR upstream pressure threshold. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
In the above embodiment, when the driver determines that the mixer crystallization needs to be processed according to the prompt information, the driver may trigger the automatic processing of the mixer crystallization by triggering the active crystallization processing switch.
Therefore, on the basis of the above embodiment, referring to fig. 3, a flow chart of a mixer crystallization detection method disclosed in another embodiment of the present invention may further include, on the basis of step S204, the steps of:
Step S205, receiving a mixer crystallization processing instruction;
in practical application, when the driver determines that the mixer crystallization needs to be processed according to the prompt information, the driver can send a mixer crystallization processing instruction to the vehicle controller by triggering the active crystallization processing switch.
and S206, adjusting the rotating speed and the torque of the engine based on the mixer crystallization processing instruction, starting the post-injection fuel oil, processing the mixer crystallization, and calibrating through PID control to enable the temperature of the upper stream of the DPF to rise in a stepped manner according to a preset temperature interval until the temperature of the upper stream of the DPF reaches the preset temperature and the stable operation time of the engine reaches the preset time.
it should be noted that the present day closed loop automatic control techniques are based on the concept of feedback to reduce uncertainty. The elements of the feedback theory include three parts: measuring, comparing and executing. What is essential to the measurement is the actual value of the controlled variable, which is compared with the desired value, and this deviation is used to correct the response of the system and to perform the regulation control. In engineering practice, the most widely used regulator control law is proportional, integral and derivative control, abbreviated as PID control, also known as PID regulation.
The value of the preset temperature interval depends on actual needs, such as 100 ℃.
The process of the temperature of the upstream of the DPF rising in steps according to the preset temperature interval can be seen in fig. 4.
DPFs (Diesel particulate filters) are classified into active regeneration and passive regeneration according to the operating principle. Passive regeneration, which means that the particulate matter collected by the filter is disposed of as soon as certain temperature and pressure conditions are reached. Active regeneration refers to when a vehicle does not reach a specific reaction condition, the active creation condition of the system is required to process the particulate matter.
After research, the inventor of the application finds that if the temperature of the upper stream of the DPF reaches 400 ℃, the mixer can be completely crystallized after running for about 1 h; if the temperature of the upper stream of the DPF reaches 500 ℃, the mixer can be completely crystallized after running for about 30 min; if the temperature of the upper stream of the DPF reaches 600 ℃, the mixer can be completely crystallized after running for about 10 min.
In this embodiment, the upstream temperature of DPF is preferably 600 deg.C, and the mixer crystallization is completed after about 10min of operation.
it should be particularly noted that step S205 and step S206 may also be executed after step S103 in the embodiment shown in fig. 1.
in summary, the mixer crystallization detection method disclosed by the invention determines whether to process the mixer crystallization by comparing the SCR upstream pressure value obtained in the vehicle running process with the SCR upstream pressure threshold, and determines to process the mixer crystallization when the SCR upstream pressure value is not less than the SCR upstream pressure threshold and the SCR upstream pressure value detected continuously for many times is not less than the SCR upstream pressure threshold. And when a mixer crystallization processing instruction is received, adjusting the rotating speed and the torque of the engine, starting the rear fuel injection, and processing mixer crystallization until the upstream temperature of the DPF reaches a preset temperature and the stable operation time of the engine reaches a preset time. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
In the above embodiment, to ensure that the mixer crystallization is completely processed, when the mixer crystallization is actively processed until the DPF upstream temperature reaches the preset temperature and the engine stable operation time reaches the preset time, the step S201 is returned to obtain the SCR upstream pressure value of the engine again, and it is continuously determined whether the SCR upstream pressure value is not less than the SCR upstream pressure threshold, and if the SCR upstream pressure value is less than the SCR upstream pressure threshold, it is determined that the mixer crystallization is completely processed.
Corresponding to the embodiment of the method, the invention also discloses a mixer crystallization detection system.
Referring to fig. 5, a schematic structural diagram of a mixer crystallization detection system according to an embodiment of the present invention is disclosed, the system including:
the acquiring unit 301 is used for acquiring the pressure value of the selective catalytic reduction SCR upstream of the engine in the running process of the vehicle;
it should be noted that the mixer crystallization detection method disclosed in the present invention is applicable to a vehicle equipped with an SCR (Selective Catalytic Reduction) tank.
SCR tank, a selective catalytic reduction device, means a device installed in an engine exhaust to reduce NO x in engine exhaust to N 2 and H 2 O by means of a reductant (NH 3), thereby reducing NO x in engine exhaust.
The embodiment obtains the SCR upstream pressure value of the engine through an SCR upstream pressure sensor of the engine.
a first determining unit 302, configured to determine whether the SCR upstream pressure value is not less than an SCR upstream pressure threshold, where the SCR upstream pressure threshold is: when the urea crystallization volume in the mixer calibrated by the engine pedestal is the maximum crystallization volume value, the exhaust gas flow rate corresponds to the SCR upstream pressure value corresponding to the SCR upstream temperature;
The SCR upstream pressure threshold value is an SCR upstream pressure value corresponding to the SCR upstream temperature and the exhaust gas flow when the urea crystallization volume in a mixer calibrated by an engine bench is the maximum crystallization volume limit value a g/cm 3.
It should be noted that, the SCR upstream Pressure MAP (intake pipe Pressure Sensor) is an SCR upstream Pressure value, where the urea crystal volume in a mixer calibrated by an engine bench is 0g/cm 3 and a g/cm 3 (theoretically acceptable maximum crystal volume limit value which does not affect various performances of the engine and causes the crystal volume when the engine power is reduced by 3%), and b g/cm 3 (too much crystal volume causes post-treatment blockage and can be solved only by replacing a post-treatment tank) where the exhaust gas flow rate corresponds to the SCR upstream temperature.
When the value of the pressure upstream of the SCR is less than the SCR upstream pressure threshold value, crystallization on the mixer is less, and the crystallization treatment is not needed.
an output unit 303, configured to output prompt information indicating that the mixer crystal needs to be processed if the first determination unit 302 determines that the mixer crystal needs to be processed.
in this embodiment, when it is determined that the detected SCR upstream pressure value is not less than the SCR upstream pressure threshold value, a prompt message is output, for example, an indicator lamp of a cab is controlled to be turned on, so that a driver knows that the mixer crystal needs to be processed.
in practical applications, the prompt message may be in other forms, such as a voice prompt, and the present invention is not limited herein.
In summary, the mixer crystallization detection system disclosed by the invention determines whether to treat the mixer crystallization by comparing the SCR upstream pressure value obtained during the running process of the vehicle with the SCR upstream pressure threshold value, and determines to treat the mixer crystallization when the SCR upstream pressure value is not less than the SCR upstream pressure threshold value. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
In order to avoid misjudgment of the trigger of the active treatment strategy of the mixer crystallization caused by the error of the detection of the pressure value at the upstream of the SCR, the invention further improves the embodiment.
Referring to fig. 6, a schematic structural diagram of a mixer crystallization detection system according to another embodiment of the present invention is disclosed, the system including:
The acquiring unit 401 is used for acquiring the pressure value of the Selective Catalytic Reduction (SCR) upstream of the engine during the running process of the vehicle;
A first determining unit 402, configured to determine whether the SCR upstream pressure value is not less than an SCR upstream pressure threshold, where the SCR upstream pressure threshold is: when the urea crystallization volume in the mixer calibrated by the engine pedestal is the maximum crystallization volume value, the exhaust gas flow rate corresponds to the SCR upstream pressure value corresponding to the SCR upstream temperature;
a determining subunit 403, configured to determine whether the number of consecutive times that the SCR upstream pressure value is not less than the SCR upstream pressure threshold reaches a preset number of times;
An output subunit 404, configured to output the prompt information if the determining subunit 404 determines that the display is a display.
in this embodiment, when it is determined that the detected SCR upstream pressure value is not less than the SCR upstream pressure threshold value, a prompt message is output, for example, an indicator lamp of a cab is controlled to be turned on, so that a driver knows that the mixer crystal needs to be processed.
In practical applications, the prompt message may be in other forms, such as a voice prompt, and the present invention is not limited herein.
In summary, the mixer crystallization detection system disclosed by the invention determines whether to process the mixer crystallization by comparing the SCR upstream pressure value obtained in the vehicle running process with the SCR upstream pressure threshold, and determines to process the mixer crystallization when the SCR upstream pressure value is not less than the SCR upstream pressure threshold and the SCR upstream pressure value detected continuously for many times is not less than the SCR upstream pressure threshold. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
In the above embodiment, when the driver determines that the mixer crystallization needs to be processed according to the prompt information, the driver may trigger the automatic processing of the mixer crystallization by triggering the active crystallization processing switch.
therefore, on the basis of the above embodiment, the detection system may further include: a receiving unit and an adjusting unit, wherein:
a receiving unit, configured to receive a mixer crystallization processing instruction after the output unit 303 outputs the hint information or the output subunit 404 outputs the hint information;
In practical application, when the driver determines that the mixer crystallization needs to be processed according to the prompt information, the driver can send a mixer crystallization processing instruction to the vehicle controller by triggering the active crystallization processing switch.
and the adjusting unit is used for adjusting the rotating speed and the torque of the engine based on the mixer crystallization processing instruction, starting the post-injection fuel oil, processing the mixer crystallization, calibrating through PID control, and enabling the DPF upstream temperature to rise in a stepped manner according to a preset temperature interval until the DPF upstream temperature of the diesel particulate filter reaches the preset temperature and the stable operation time of the engine reaches the preset time.
DPFs (Diesel particulate filters) are classified into active regeneration and passive regeneration according to the operating principle. Passive regeneration, which means that the particulate matter collected by the filter is disposed of as soon as certain temperature and pressure conditions are reached. Active regeneration refers to when a vehicle does not reach a specific reaction condition, the active creation condition of the system is required to process the particulate matter.
After research, the inventor of the application finds that if the temperature of the upper stream of the DPF reaches 400 ℃, the mixer can be completely crystallized after running for about 1 h; if the temperature of the upper stream of the DPF reaches 500 ℃, the mixer can be completely crystallized after running for about 30 min; if the temperature of the upper stream of the DPF reaches 600 ℃, the mixer can be completely crystallized after running for about 10 min.
in this embodiment, the upstream temperature of DPF is preferably 600 deg.C, and the mixer crystallization is completed after about 10min of operation.
in summary, the mixer crystallization detection system disclosed by the invention determines whether to process the mixer crystallization by comparing the SCR upstream pressure value obtained in the vehicle running process with the SCR upstream pressure threshold, and determines to process the mixer crystallization when the SCR upstream pressure value is not less than the SCR upstream pressure threshold and the SCR upstream pressure value detected continuously for many times is not less than the SCR upstream pressure threshold. And when a mixer crystallization processing instruction is received, adjusting the rotating speed and the torque of the engine, starting the rear fuel injection, and processing mixer crystallization until the upstream temperature of the DPF reaches a preset temperature and the stable operation time of the engine reaches a preset time. The mixer crystallization detection method disclosed by the invention is not influenced by the performance of an engine, so that the detection precision of the mixer crystallization is greatly improved, and the timely and effective treatment of the mixer crystallization is effectively ensured.
In the above embodiment, to ensure that the mixer crystallization is completely processed, when the mixer crystallization is actively processed until the DPF upstream temperature reaches the preset temperature and the engine stable operation time reaches the preset time, the step S201 is returned to obtain the SCR upstream pressure value of the engine again, and it is continuously determined whether the SCR upstream pressure value is not less than the SCR upstream pressure threshold, and if the SCR upstream pressure value is less than the SCR upstream pressure threshold, it is determined that the mixer crystallization is completely processed.
accordingly, the detection system may further comprise:
the re-acquisition unit is used for adjusting the rotating speed and the torque of the engine based on the mixer crystallization processing instruction, starting the post-injection fuel oil, processing mixer crystallization until the upstream temperature of the DPF of the diesel particulate filter reaches a preset temperature and the stable operation time of the engine reaches a preset time, and then acquiring the upstream pressure value of the SCR again;
The second judgment unit is used for judging whether the SCR upstream pressure value acquired again is not less than the SCR upstream pressure threshold value;
a determination unit configured to determine that the mixer is completely crystallized if the second determination unit determines yes.
it should be noted that, for the specific operation of each component in the system embodiment, reference is made to the corresponding part of the method embodiment, and details are not described here.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be 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. Also, 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 an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present 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 disclosed herein.
Claims (11)
1. a mixer crystallization detection method, comprising:
Acquiring the pressure value of the selective catalytic reduction SCR upstream of the engine in the running process of the vehicle;
Judging whether the SCR upstream pressure value is not less than an SCR upstream pressure threshold value, wherein the SCR upstream pressure threshold value is as follows: when the urea crystallization volume in the mixer calibrated by the engine pedestal is the maximum crystallization volume value, the exhaust gas flow rate corresponds to the SCR upstream pressure value corresponding to the SCR upstream temperature;
And if the SCR upstream pressure value is not less than the SCR upstream pressure threshold value, outputting prompt information, wherein the prompt information is used for indicating that the mixer crystallization needs to be treated.
2. Detection method according to claim 1, characterised in that the calibration procedure of the SCR upstream pressure threshold is:
And crystallizing the mixer by adopting a rapid crystallization method, calibrating the SCR upstream pressure based on the engine exhaust gas flow and the SCR upstream temperature by taking the crystallization amount when the engine performance is degraded as a reference when the crystallization amount causes the degradation of the engine performance, and determining the calibrated SCR upstream pressure as the SCR upstream pressure threshold.
3. The detection method according to claim 1, wherein if the SCR upstream pressure value is not less than the SCR upstream pressure threshold, outputting a prompt message specifically includes:
Judging whether the continuous times that the SCR upstream pressure value is not less than the SCR upstream pressure threshold value reach preset times or not;
If yes, outputting the prompt message.
4. The detection method according to any one of claims 1 to 3, further comprising, after the outputting the prompt information:
receiving a mixer crystallization processing instruction;
based on the mixer crystallization processing instruction, the rotating speed and the torque of the engine are adjusted, fuel oil is injected after the engine is started, mixer crystallization is processed, and the mixer crystallization is calibrated through PID control, so that the temperature of the DPF upstream rises in a stepped mode according to a preset temperature interval until the temperature of the DPF upstream of the diesel particulate filter reaches the preset temperature, and the stable operation time of the engine reaches the preset time.
5. The detection method according to claim 4, wherein the preset temperature is 600 ℃ and the preset time is 10 min.
6. the sensing method according to claim 4, wherein after said adjusting the engine speed and torque based on said mixer crystallization processing command and starting the post-injection fuel, processing the mixer crystallization until the temperature upstream of the DPF reaches a preset temperature and the engine steady operation time reaches a preset time, further comprising:
Acquiring the SCR upstream pressure value again;
Judging whether the SCR upstream pressure value obtained again is not less than the SCR upstream pressure threshold value;
If so, the mixer is determined to be fully crystallized.
7. A mixer crystallization detection system, comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring the pressure value of the selective catalytic reduction SCR upstream of an engine in the running process of a vehicle;
the first judging unit is used for judging whether the SCR upstream pressure value is not less than an SCR upstream pressure threshold value, wherein the SCR upstream pressure threshold value is as follows: when the urea crystallization volume in the mixer calibrated by the engine pedestal is the maximum crystallization volume value, the exhaust gas flow rate corresponds to the SCR upstream pressure value corresponding to the SCR upstream temperature;
and the output unit is used for outputting prompt information under the condition that the first judgment unit judges that the crystals of the mixer need to be processed.
8. The detection system according to claim 7, wherein the output unit specifically comprises:
The judging subunit is used for judging whether the continuous times that the SCR upstream pressure value is not less than the SCR upstream pressure threshold value reach preset times or not;
And the output subunit is used for outputting the prompt information under the condition that the judgment subunit judges that the prompt information is positive.
9. The detection system of claim 7, further comprising:
a receiving unit, configured to receive a mixer crystallization processing instruction after the output unit outputs the prompt information or the output subunit outputs the prompt information;
And the adjusting unit is used for adjusting the rotating speed and the torque of the engine based on the mixer crystallization processing instruction, starting the post-injection fuel oil, processing the mixer crystallization, calibrating through PID control, and enabling the DPF upstream temperature to rise in a stepped manner according to a preset temperature interval until the DPF upstream temperature of the diesel particulate filter reaches the preset temperature and the stable operation time of the engine reaches the preset time.
10. the detection system according to claim 9, wherein the preset temperature is 600 ℃ and the preset time is 10 min.
11. The detection system of claim 9, further comprising:
The re-acquisition unit is used for adjusting the rotating speed and the torque of the engine based on the mixer crystallization processing instruction, starting the post-injection fuel oil, processing mixer crystallization until the upstream temperature of the DPF of the diesel particulate filter reaches a preset temperature and the stable operation time of the engine reaches a preset time, and then acquiring the upstream pressure value of the SCR again;
The second judgment unit is used for judging whether the SCR upstream pressure value acquired again is not less than the SCR upstream pressure threshold value;
A determination unit configured to determine that the mixer is completely crystallized if the second determination unit determines yes.
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