CN113027581B - Method and device for detecting sulfur poisoning of SCR (Selective catalytic reduction) catalyst - Google Patents
Method and device for detecting sulfur poisoning of SCR (Selective catalytic reduction) catalyst Download PDFInfo
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- CN113027581B CN113027581B CN202110352346.8A CN202110352346A CN113027581B CN 113027581 B CN113027581 B CN 113027581B CN 202110352346 A CN202110352346 A CN 202110352346A CN 113027581 B CN113027581 B CN 113027581B
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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
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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
- F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
- F01N2550/02—Catalytic activity of catalytic converters
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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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/04—Methods of control or diagnosing
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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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
- F01N2900/1614—NOx amount trapped in catalyst
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Abstract
The application provides a method and a device for detecting sulfur poisoning of an SCR (selective catalytic reduction) catalyst, wherein the method comprises the following steps: respectively obtaining the mass of nitrogen oxides at the upstream and downstream of an SCR catalyst in a first time period and a second time period in the regeneration process of a particle collector, calculating the conversion efficiency of the SCR catalyst in the first time period and the second time period, calculating the difference value of the conversion efficiency in the first time period and the conversion efficiency in the second time period, and if the difference value of the conversion efficiency is greater than a preset error value, determining that the SCR catalyst is sulfur poisoning. And obtaining a detection result of the sulfur poisoning of the SCR catalyst by comparing the conversion efficiency of the SCR catalyst in two stages before and after the regeneration of the particle complementing collector. The embodiment of the application can detect the sulfur poisoning of the SCR catalyst by utilizing the regeneration of the particle collector, the detection mode is simple and convenient, and the detection result is accurate.
Description
Technical Field
The invention relates to the field of vehicles, in particular to a method and a device for detecting sulfur poisoning of an SCR (selective catalytic reduction) catalyst.
Background
Nowadays, the society pays more and more attention to the environmental protection, so the treatment technology aiming at the automobile exhaust is also improved. The current system for treating the automobile tail gas by the diesel automobile comprises a Selective Catalytic Reduction (SCR) catalyst, and the SCR catalyst is used for mixing nitrogen oxide in the tail gas of the diesel automobile with ammonia gas in urea and then generating nitrogen and water after a Reduction reaction is carried out under a high-temperature environment through catalysis of the SCR catalyst, so that the pollution of the automobile tail gas to the environment can be reduced.
At present, the SCR catalyst is generally mainly copper-based catalyst, is sensitive to the sulfur content in the burning oil product, and can cause sulfur poisoning of the SCR catalyst due to excessively high sulfur content, namely the copper-based catalyst and the sulfur in the SCR catalyst are combined to generate other impurities, so that the conversion efficiency of nitrogen oxide of the SCR catalyst is reduced, even the nitrogen oxide cannot be reduced, and the discharged tail gas contains the nitrogen oxide to pollute the environment.
Therefore, an effective method for detecting sulfur poisoning of the SCR catalyst is urgently needed.
Disclosure of Invention
In view of the above, the present application aims to provide an effective method for detecting sulfur poisoning of an SCR catalyst.
The embodiment of the application provides a method for detecting sulfur poisoning of an SCR (selective catalytic reduction) catalyst, which comprises the following steps:
respectively obtaining the mass of nitrogen oxides at the upstream and downstream of the SCR catalyst in a first time period and a second time period in the regeneration process of the particle collector, and calculating the conversion efficiency of the SCR catalyst in the first time period and the second time period; wherein the conversion efficiency of the SCR catalyst is calculated according to the mass of the nitrogen oxide upstream of the SCR catalyst and the mass of the nitrogen oxide downstream of the SCR catalyst in a corresponding time period when the mass of the nitrogen oxide upstream of the SCR catalyst reaches a preset mass threshold value;
calculating the difference value between the conversion efficiency of the first time period and the conversion efficiency of the second time period, and if the difference value of the conversion efficiencies is larger than a preset error value, determining that the detection result is the sulfur poisoning of the SCR catalyst;
wherein the first time period is a time period in a light-off phase of the particulate recollector regeneration process and the second time period is a time period in a cooling phase of the particulate recollector regeneration process.
Optionally, the calculating the conversion efficiency of the SCR catalysts in the first and second periods of time includes:
calculating the difference between the mass of the nitrogen oxides at the upstream of the SCR catalyst and the mass of the nitrogen oxides at the downstream of the SCR catalyst in the corresponding time period;
and calculating the mass difference and the mass ratio of the nitrogen oxides at the upstream of the SCR catalyst in the corresponding time period, wherein the mass ratio is the conversion efficiency in the corresponding time period.
Optionally, before obtaining the mass of the nitrogen oxides upstream and downstream of the SCR catalyst for the first and second periods of time, respectively, during regeneration of the particulate filter, the method further comprises:
confirming that the detected values of the nitrogen oxide sensors upstream of the SCR catalyst and downstream of the SCR catalyst are effective;
maintaining a temperature upstream of the SCR catalyst within a predetermined temperature range;
maintaining a concentration of nitrogen oxides upstream of the SCR catalyst within a predetermined concentration range;
maintaining the mass flow of the exhaust gas within a predetermined mass flow range.
Optionally, before maintaining the temperature upstream of the SCR catalyst within the predetermined temperature range, the method further comprises:
confirming that a temperature upstream of the particulate replenishment reservoir reaches a temperature threshold.
Optionally, the method further includes:
receiving an SCR catalyst sulfur poisoning detection request during a regeneration light-off phase of the particulate supplement DPF to perform SCR catalyst sulfur poisoning detection.
Optionally, the mass of the nox is detected by a nox sensor, and the predetermined error value is an error value of the nox sensor.
The embodiment of the application provides a SCR catalyst converter sulfur poisoning detection device, includes:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for respectively acquiring the mass of nitrogen oxides at the upstream and downstream of an SCR catalyst in a first time period and a second time period in the regeneration process of a particle complementing device and calculating the conversion efficiency of the SCR catalyst in the first time period and the second time period; wherein the conversion efficiency of the SCR catalyst is calculated according to the mass of the nitrogen oxide upstream of the SCR catalyst and the mass of the nitrogen oxide downstream of the SCR catalyst in a corresponding time period when the mass of the nitrogen oxide upstream of the SCR catalyst reaches a preset mass threshold value;
the calculation unit is used for calculating the difference value of the conversion efficiency of the first time period and the conversion efficiency of the second time period, and if the difference value of the conversion efficiencies is larger than a preset error value, the detection result is the sulfur poisoning of the SCR catalyst;
wherein the first time period is a time period in a light-off phase of the particulate recollector regeneration process and the second time period is a time period in a cooling phase of the particulate recollector regeneration process.
Optionally, the obtaining, by the obtaining unit, the conversion efficiencies of the SCR catalysts in the first time period and the second time period includes:
the acquiring unit calculates and obtains the difference value between the mass of the nitrogen oxide at the upstream of the SCR catalyst and the mass of the nitrogen oxide at the downstream of the SCR catalyst in a corresponding time period;
the obtaining unit calculates and obtains the mass difference and the mass ratio of the nitrogen oxides at the upstream of the SCR catalyst in the corresponding time period, wherein the mass ratio is the conversion efficiency in the corresponding time period.
Optionally, before the obtaining unit obtains the mass of the nitrogen oxides upstream and downstream of the SCR catalyst in the first and second periods during regeneration of the particulate filter, respectively, the apparatus further includes:
a first confirming unit for confirming that the detected values of the nitrogen oxide sensors upstream of the SCR catalyst and downstream of the SCR catalyst are valid;
a first holding unit for holding a temperature upstream of the SCR catalyst within a predetermined temperature range;
a second holding unit for holding a concentration of nitrogen oxides upstream of the SCR catalyst within a predetermined concentration range;
and the third maintaining unit is used for maintaining the mass flow of the tail gas within a preset mass flow range.
Optionally, before the first holding unit holds the temperature upstream of the SCR catalyst within the predetermined temperature range, the apparatus further includes:
a second confirmation unit for confirming that the temperature upstream of the particle complement has reached a temperature threshold.
Optionally, the apparatus further comprises:
a receiving unit, configured to receive a request for detecting SCR catalyst sulfur poisoning during a regeneration light-off phase of the DPF for performing SCR catalyst sulfur poisoning detection.
Optionally, the mass of the nox is detected by a nox sensor, and the predetermined error value is an error value of the nox sensor.
The method for detecting the sulfur poisoning of the SCR catalyst provided by the embodiment of the application is to add detection on the conversion efficiency of the SCR catalyst in two stages of DPF regeneration of a particle collector. The regeneration of the DPF of the particle collector comprises a desulfurization treatment process, if the oil used by the vehicle contains sulfur, a part of sulfur in the tail gas of the automobile is treated during the regeneration of the DPF of the particle collector, so that if the SCR catalyst is not poisoned by sulfur, namely the oil contains no sulfur, the conversion efficiency of the SCR catalyst before and after the regeneration of the DPF of the particle collector is not changed, and if the SCR catalyst is poisoned by sulfur, namely the oil contains sulfur, the conversion efficiency of the SCR catalyst is changed by desulfurization treatment before and after the regeneration of the DPF of the particle collector. That is, the detection result of the sulfur poisoning of the SCR catalyst is obtained by comparing the conversion efficiency of the SCR catalyst in two stages before and after the DPF regeneration of the particulate filter. The embodiment of the application can utilize the regeneration of the DPF of the particle collector to detect the sulfur poisoning of the SCR catalyst, the detection mode is simple and convenient, and the detection result is accurate.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic diagram of a particulate replenishment regeneration process of the prior art;
FIG. 2 is a flow chart illustrating a method for detecting sulfur poisoning of an SCR catalyst according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram illustrating a particle replenishment device regeneration process according to an embodiment of the present application;
fig. 4 shows a block diagram of an SCR catalyst sulfur poisoning detection apparatus according to an embodiment of the present application.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways than those described herein, and it will be apparent to those of ordinary skill in the art that the present application is not limited by the specific embodiments disclosed below.
Nowadays, the society pays more and more attention to the environmental protection, so the treatment technology aiming at the automobile exhaust is also improved. The current system for treating the automobile tail gas by the diesel automobile comprises a Selective Catalytic Reduction (SCR) catalyst, and the SCR catalyst is used for mixing nitrogen oxide in the tail gas of the diesel automobile with ammonia gas in urea and then generating nitrogen and water after a Reduction reaction is carried out under a high-temperature environment through catalysis of the SCR catalyst, so that the pollution of the automobile tail gas to the environment can be reduced.
At present, the SCR catalyst is generally mainly copper-based catalyst, is sensitive to the sulfur content in the burning oil product, and can cause sulfur poisoning of the SCR catalyst due to excessively high sulfur content, namely the copper-based catalyst and the sulfur in the SCR catalyst are combined to generate other impurities, so that the conversion efficiency of nitrogen oxide of the SCR catalyst is reduced, even the nitrogen oxide cannot be reduced, and the discharged tail gas contains the nitrogen oxide to pollute the environment.
Therefore, an effective method for detecting sulfur poisoning of the SCR catalyst is urgently needed.
The inventor finds that the regeneration process of the particle collector is schematically shown in fig. 1. As can be seen from the figure, the regeneration process of a Particulate Filter (DPF) can be divided into 3 stages: a light-off phase, a regeneration phase and a cooling phase. When the regeneration stage of the DPF of the particle collector is carried out, a desulfurization treatment process is included. Some conditions in the regeneration process of the DPF of the particle collector meet the condition for detecting sulfur poisoning of the SCR catalyst, and the regeneration stage of the DPF of the particle collector comprises a desulfurization treatment process, if fuel oil of a vehicle comprises sulfur, the conversion efficiency of the SCR catalyst can be changed before and after regeneration after the desulfurization treatment, and if the fuel oil of the vehicle does not comprise sulfur, the conversion efficiency of the SCR catalyst can not be changed before and after regeneration after the desulfurization treatment.
Based on this, the embodiment of the application provides a method for detecting sulfur poisoning of an SCR catalyst, including: respectively obtaining the mass of nitrogen oxides at the upstream and downstream of the SCR catalyst in a first time period and a second time period in the regeneration process of the particle collector, and calculating the conversion efficiency of the SCR catalyst in the first time period and the second time period; wherein the conversion efficiency of the SCR catalyst is calculated according to the mass of the nitrogen oxide upstream of the SCR catalyst and the mass of the nitrogen oxide downstream of the SCR catalyst in a corresponding time period when the mass of the nitrogen oxide upstream of the SCR catalyst reaches a preset mass threshold value; and calculating the difference between the conversion efficiency in the first time period and the conversion efficiency in the second time period, and if the difference is larger than a preset error value, determining that the SCR catalyst is sulfur poisoning, wherein the first time period is the time period in the ignition stage of the regeneration process of the particle collector, and the second time period is the time period in the cooling stage of the regeneration process of the particle collector.
The method for detecting the sulfur poisoning of the SCR catalyst provided by the embodiment of the application is to add detection on the conversion efficiency of the SCR catalyst in two stages of DPF regeneration of a particle collector. The regeneration of the DPF of the particle collector comprises a desulfurization treatment process, if the oil used by the vehicle contains sulfur, a part of sulfur in the tail gas of the automobile is treated during the regeneration of the DPF of the particle collector, so that if the SCR catalyst is not poisoned by sulfur, namely the oil contains no sulfur, the conversion efficiency of the SCR catalyst before and after the regeneration of the DPF of the particle collector is not changed, and if the SCR catalyst is poisoned by sulfur, namely the oil contains sulfur, the conversion efficiency of the SCR catalyst is changed by desulfurization treatment before and after the regeneration of the DPF of the particle collector. That is, the detection result of the sulfur poisoning of the SCR catalyst is obtained by comparing the conversion efficiency of the SCR catalyst in two stages before and after the DPF regeneration of the particulate filter. The embodiment of the application can utilize the regeneration of the DPF of the particle collector to detect the sulfur poisoning of the SCR catalyst, the detection mode is simple and convenient, and the detection result is accurate.
For a better understanding of the technical solutions and effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.
Referring to fig. 2, the figure is a flowchart of a method for detecting sulfur poisoning of an SCR catalyst according to an embodiment of the present application. The method for detecting the sulfur poisoning of the SCR catalyst comprises the following steps:
s201, respectively obtaining the mass of nitrogen oxides at the upstream and downstream of the SCR catalyst in a first time period and a second time period in the regeneration process of the particle complementing device, and calculating the conversion efficiency of the SCR catalyst in the first time period and the second time period; wherein the conversion efficiency of the SCR catalyst is calculated from the mass of nitrogen oxides upstream of the SCR catalyst and the mass of nitrogen oxides downstream of the SCR catalyst for a corresponding time period when the mass of nitrogen oxides upstream of the SCR catalyst reaches a predetermined mass threshold, wherein the first time period is a time period in a light-off phase of the particulate filter regeneration process and the second time period is a time period in a cooling phase of the particulate filter regeneration process.
In an embodiment of the application, the mass of nitrogen oxides upstream and downstream of the SCR catalyst is obtained for a first period of time and a second period of time, respectively, during regeneration of the particulate trap DPF, the first period of time being a period of time in a light-off phase of the particulate trap DPF, and the second period of time being a period of time in a cooling phase of the particulate trap DPF. The first time period may be different in time length from the second time period.
Referring to fig. 3, a schematic diagram of a regeneration process of a particle replenishment device according to an embodiment of the present application is shown. In the figure, an SCR efficiency monitoring stage 1 is used for acquiring the mass of nitrogen oxides at the upstream and the downstream of an SCR catalyst in a first time period, and an SCR efficiency monitoring stage 2 is used for acquiring the mass of the nitrogen oxides at the upstream and the downstream of the SCR catalyst in a second time period. That is, during the light-off phase of the particulate-fed DPF regeneration process, the mass of nitrogen oxides upstream and downstream of the SCR catalyst is simultaneously captured during a first time period, and during the cooling phase of the particulate-fed DPF regeneration process, the mass of nitrogen oxides upstream and downstream of the SCR catalyst is simultaneously captured during a second time period.
In practical application, the quality of the nitrogen oxide can be detected by a nitrogen oxide sensor. Specifically, the mass flow rate of the nitrogen oxide detected by the nitrogen oxide sensor may be an integral value of the mass flow rate of the nitrogen oxide over a period of time, and the integral value is the mass of the nitrogen oxide over the period of time. The unit of mass flow may be kilograms per hour (kg/h)
In the embodiment of the application, when the mass of the nitrogen oxide upstream of the SCR catalyst reaches a preset mass threshold value, the conversion efficiency of the SCR catalyst in the first time period and the second time period is calculated according to the mass of the nitrogen oxide upstream of the SCR catalyst and the mass of the nitrogen oxide downstream of the SCR catalyst in the corresponding time period.
That is, during the light-off phase of the regeneration of the DPF during the particulate supplement, when the mass of nitrogen oxides upstream of the SCR catalyst reaches a predetermined mass threshold value within a first time period, the conversion efficiency of the SCR catalyst for the first time period is calculated based on the mass of nitrogen oxides upstream of the SCR catalyst during the first time period and the mass of nitrogen oxides downstream of the SCR catalyst during the first time period. During the cooling phase during regeneration of the DPF of the particulate filter, when the mass of nitrogen oxides upstream of the SCR catalyst reaches a predetermined mass threshold value during a second period of time, the conversion efficiency of the SCR catalyst during the second period of time is calculated on the basis of the mass of nitrogen oxides upstream of the SCR catalyst during the second period of time and the mass of nitrogen oxides downstream of the SCR catalyst during the second period of time.
In the embodiments of the present application, the value of the predetermined quality threshold is not particularly limited. As an example, the predetermined quality threshold may be 15 grams (g). In the ignition stage and the cooling stage, the same preset quality threshold value is used as a precondition for triggering the calculation of the conversion efficiency of the SCR catalyst, so that other influence factors of the conversion efficiency of the SCR catalyst calculated in the two stages are basically the same, and the influence of the other influence factors on the detection of the sulfur poisoning of the SCR catalyst is reduced.
As a possible implementation, the conversion efficiency of the SCR catalyst for the first and second periods of time may be calculated by:
calculating to obtain the difference value between the mass of the nitrogen oxide at the upstream of the SCR catalyst and the mass of the nitrogen oxide at the downstream of the SCR catalyst in the corresponding time period, and calculating to obtain the ratio of the difference value between the masses and the mass of the nitrogen oxide at the upstream of the SCR catalyst in the corresponding time period, wherein the mass ratio is the conversion efficiency in the corresponding time period.
That is, during the light-off phase of the regeneration of the DPF during the particulate filter, the difference between the mass of nitrogen oxides upstream of the SCR catalyst during the first period of time and the mass of nitrogen oxides downstream of the SCR catalyst during the first period of time is calculated, the difference in mass is divided by the mass of nitrogen oxides upstream of the SCR catalyst during the first period of time, and the ratio of the masses obtained is the SCR catalyst conversion efficiency during the first period of time. In the cooling phase of the regeneration process of the DPF of the particle collector, the difference value of the mass of the nitrogen oxide at the upstream of the SCR catalyst in the second time period and the mass of the nitrogen oxide at the downstream of the SCR catalyst in the second time period is calculated, the obtained difference value of the masses is divided with the mass of the nitrogen oxide at the upstream of the SCR catalyst in the second time period, and the obtained ratio of the masses is the conversion efficiency of the SCR catalyst in the second time period.
S202, calculating a difference value between the conversion efficiency in the first time period and the conversion efficiency in the second time period, and if the difference value is larger than a preset error value, determining that the SCR catalyst is poisoned with sulfur.
In the embodiment of the application, after the conversion efficiency in the first time period and the conversion efficiency in the second time period are calculated, the difference between the conversion efficiency in the first time period and the conversion efficiency in the second time period is calculated, and if the difference between the conversion efficiencies is greater than a predetermined error value, the detection result is the SCR catalyst sulfur poisoning.
That is, by comparing the SCR catalyst conversion efficiency in the first time period with the SCR catalyst conversion efficiency in the second time period, if the conversion efficiencies are the same or the difference between the conversion efficiencies is less than a predetermined error value, it is determined that the SCR catalyst is not poisoned with sulfur, that is, the oil of the vehicle does not contain sulfur; if the difference value of the conversion efficiencies is larger than the preset error value, the desulfurization treatment of the DPF in the regeneration process of the particle collector enables the conversion efficiency of the SCR catalyst to be changed before and after regeneration, and the sulfur poisoning of the SCR catalyst is confirmed, namely the sulfur is contained in oil products of vehicles.
In the embodiment of the present application, the value of the predetermined error value is not particularly limited. As a possible implementation, the predetermined error value may be an error value of the nox sensor, for example, the error value of the nox sensor may be 0.1.
In the embodiment of the application, when the detection result is SCR catalyst sulfur poisoning, alarm processing can be carried out, a vehicle user is reminded of the SCR catalyst sulfur poisoning, and sulfur cleaning and replacement of the SCR catalyst are carried out in time to avoid sulfur-containing oil.
In the embodiment of the application, before the quality of the nitrogen oxides upstream and downstream of the SCR catalyst in the first time period and the second time period in the regeneration process of the particulate filter is respectively obtained, the detection condition of the sulfur poisoning of the SCR catalyst can be kept consistent, that is, the conversion efficiency of the SCR catalyst is detected in the first time period and the second time period under the same condition, so that the accuracy of the detection result of the sulfur poisoning of the SCR catalyst can be improved.
As a possible implementation, it is confirmed that the detected values of the nitrogen oxide sensors upstream and downstream of the SCR catalyst are valid, the temperature upstream of the SCR catalyst is maintained within a predetermined temperature range, the concentration of the nitrogen oxide upstream of the SCR catalyst is maintained within a predetermined concentration range, and the mass flow rate of the exhaust gas is maintained within a predetermined mass flow rate range. Confirming that the detected values of the nitrogen oxide sensors upstream of the SCR catalyst and downstream of the SCR catalyst are effective can avoid inaccurate detected results caused by the failure of the nitrogen oxide sensors. The temperature upstream of the SCR catalyst is kept within a predetermined temperature range, which may be a temperature range for optimum efficiency conversion of the SCR catalyst in order to increase the accuracy of the detection result of the conversion efficiency of the SCR catalyst, for example the predetermined temperature range may be 230 ℃ -270 ℃. The predetermined concentration may be in units of parts per million (ppm) and the predetermined concentration may range from 50ppm to 1500 ppm. The predetermined mass flow rate range may be 350Kg/h to 1600 Kg/h.
Before the detection conditions are kept consistent, the temperature of the upstream of the particulate filter DPF can be detected, and after the temperature of the upstream of the particulate filter DPF is confirmed to reach the temperature threshold value, the subsequent steps of detecting the sulfur poisoning of the SCR catalyst can be continued. The temperature threshold may be 300 ℃.
In an embodiment of the application, an SCR catalyst sulfur poisoning detection request may be received for SCR catalyst sulfur poisoning detection during a light-off phase after the particulate filler DPF enters a regeneration process. If the SCR catalyst sulfur poisoning detection request is not triggered, only the regeneration process of the DPF of the particle supplement device is needed, and the SCR catalyst sulfur poisoning detection is not needed, so that the original regeneration of the DPF of the particle supplement device cannot be influenced by the SCR catalyst sulfur poisoning detection.
In practical applications, when the temperature of the particulate filler DPF is up to 250 ℃ and a request for SCR catalyst sulfur poisoning detection is received while the particulate filler DPF is in the light-off phase, SCR catalyst sulfur poisoning detection is entered. The SCR catalyst sulfur poisoning detection request may include the following conditions: no crystal exists in the tail gas treatment system, the nitrogen oxide sensor is confirmed to be free of fault, the detection value is effective, and the tail gas treatment system reports that the conversion efficiency of the SCR catalyst is reduced. After the exhaust treatment system reports a decrease in SCR catalyst conversion efficiency, it may be confirmed by the SCR catalyst sulfur poisoning detection whether the decrease in SCR catalyst conversion efficiency is due to SCR catalyst sulfur poisoning or due to other influencing factors.
The method for detecting the sulfur poisoning of the SCR catalyst provided by the embodiment of the application is to add detection on the conversion efficiency of the SCR catalyst in two stages of DPF regeneration of a particle collector. The regeneration of the DPF of the particle collector comprises a desulfurization treatment process, if the oil used by the vehicle contains sulfur, a part of sulfur in the tail gas of the automobile is treated during the regeneration of the DPF of the particle collector, so that if the SCR catalyst is not poisoned by sulfur, namely the oil contains no sulfur, the conversion efficiency of the SCR catalyst before and after the regeneration of the DPF of the particle collector is not changed, and if the SCR catalyst is poisoned by sulfur, namely the oil contains sulfur, the conversion efficiency of the SCR catalyst is changed by desulfurization treatment before and after the regeneration of the DPF of the particle collector. That is, the detection result of the sulfur poisoning of the SCR catalyst is obtained by comparing the conversion efficiency of the SCR catalyst in two stages before and after the DPF regeneration of the particulate filter. The embodiment of the application can utilize the regeneration of the DPF of the particle collector to detect the sulfur poisoning of the SCR catalyst, the detection mode is simple and convenient, and the detection result is accurate.
Based on the method for detecting sulfur poisoning of the SCR catalyst provided by the above embodiment, the embodiment of the present application further provides a device for detecting sulfur poisoning of the SCR catalyst, and the working principle of the device is described in detail below with reference to the accompanying drawings.
Referring to fig. 4, the figure is a block diagram of a device for detecting sulfur poisoning of an SCR catalyst according to an embodiment of the present disclosure.
The SCR catalyst sulfur poisoning detection apparatus 400 according to the present embodiment includes:
an obtaining unit 410, configured to obtain the mass of nitrogen oxides upstream and downstream of the SCR catalyst in a first time period and a second time period in a regeneration process of the particulate filter, respectively, and calculate conversion efficiencies of the SCR catalyst in the first time period and the second time period; wherein the conversion efficiency of the SCR catalyst is calculated according to the mass of the nitrogen oxide upstream of the SCR catalyst and the mass of the nitrogen oxide downstream of the SCR catalyst in a corresponding time period when the mass of the nitrogen oxide upstream of the SCR catalyst reaches a preset mass threshold value;
a calculating unit 420, configured to calculate a difference between the conversion efficiency in the first time period and the conversion efficiency in the second time period, and if the difference is greater than a predetermined error value, the detection result is the SCR catalyst sulfur poisoning;
wherein the first time period is a time period in a light-off phase of the particulate recollector regeneration process and the second time period is a time period in a cooling phase of the particulate recollector regeneration process.
Optionally, the obtaining, by the obtaining unit, the conversion efficiencies of the SCR catalysts in the first time period and the second time period includes:
the acquiring unit calculates and obtains the difference value between the mass of the nitrogen oxide at the upstream of the SCR catalyst and the mass of the nitrogen oxide at the downstream of the SCR catalyst in a corresponding time period;
the obtaining unit calculates and obtains the mass difference and the mass ratio of the nitrogen oxides at the upstream of the SCR catalyst in the corresponding time period, wherein the mass ratio is the conversion efficiency in the corresponding time period.
Optionally, before the obtaining unit obtains the mass of the nitrogen oxides upstream and downstream of the SCR catalyst in the first and second periods during regeneration of the particulate filter, respectively, the apparatus further includes:
a first confirming unit for confirming that the detected values of the nitrogen oxide sensors upstream of the SCR catalyst and downstream of the SCR catalyst are valid;
a first holding unit for holding a temperature upstream of the SCR catalyst within a predetermined temperature range;
a second holding unit for holding a concentration of nitrogen oxides upstream of the SCR catalyst within a predetermined concentration range;
and the third maintaining unit is used for maintaining the mass flow of the tail gas within a preset mass flow range.
Optionally, before the first holding unit holds the temperature upstream of the SCR catalyst within the predetermined temperature range, the apparatus further includes:
a second confirmation unit for confirming that the temperature upstream of the particle complement has reached a temperature threshold.
Optionally, the apparatus further comprises:
a receiving unit, configured to receive a request for detecting SCR catalyst sulfur poisoning during a regeneration light-off phase of the DPF for performing SCR catalyst sulfur poisoning detection.
Optionally, the mass of the nox is detected by a nox sensor, and the predetermined error value is an error value of the nox sensor.
When introducing elements of various embodiments of the present application, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.
It should be noted that, as one of ordinary skill in the art would understand, all or part of the processes of the above method embodiments may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when executed, the computer program may include the processes of the above method embodiments. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus embodiment, since it is substantially similar to the method embodiment, it is relatively simple to describe, and reference may be made to some descriptions of the method embodiment for relevant points.
The foregoing is merely a preferred embodiment of the present application and, although the present application discloses the foregoing preferred embodiments, the present application is not limited thereto. Those skilled in the art can now make numerous possible variations and modifications to the disclosed embodiments, or modify equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the claimed embodiments. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still fall within the protection scope of the technical solution of the present application without departing from the content of the technical solution of the present application.
Claims (10)
1. An SCR catalyst sulfur poisoning detection method is characterized by comprising the following steps:
respectively obtaining the mass of nitrogen oxides at the upstream and downstream of the SCR catalyst in a first time period and a second time period in the regeneration process of the particle collector, and calculating the conversion efficiency of the SCR catalyst in the first time period and the second time period; wherein the conversion efficiency of the SCR catalyst is calculated according to the mass of the nitrogen oxide upstream of the SCR catalyst and the mass of the nitrogen oxide downstream of the SCR catalyst in a corresponding time period when the mass of the nitrogen oxide upstream of the SCR catalyst reaches a preset mass threshold value;
calculating the difference value between the conversion efficiency of the first time period and the conversion efficiency of the second time period, and if the difference value of the conversion efficiencies is larger than a preset error value, determining that the detection result is the sulfur poisoning of the SCR catalyst;
wherein the first time period is a time period in a light-off phase of the particulate recollector regeneration process and the second time period is a time period in a cooling phase of the particulate recollector regeneration process.
2. The method of claim 1, wherein the calculating conversion efficiencies for the first and second time periods of the SCR catalyst comprises:
calculating the difference between the mass of the nitrogen oxides at the upstream of the SCR catalyst and the mass of the nitrogen oxides at the downstream of the SCR catalyst in the corresponding time period;
and calculating the mass difference and the mass ratio of the nitrogen oxides at the upstream of the SCR catalyst in the corresponding time period, wherein the mass ratio is the conversion efficiency in the corresponding time period.
3. The method of claim 1, wherein prior to obtaining the mass of nitrogen oxides upstream and downstream of the SCR catalyst for the first and second periods of time, respectively, during regeneration of the particulate replenisher, the method further comprises:
confirming that the detected values of the nitrogen oxide sensors upstream of the SCR catalyst and downstream of the SCR catalyst are effective;
maintaining a temperature upstream of the SCR catalyst within a predetermined temperature range;
maintaining a concentration of nitrogen oxides upstream of the SCR catalyst within a predetermined concentration range;
maintaining the mass flow of the exhaust gas within a predetermined mass flow range.
4. The method of claim 3, further comprising, before maintaining the temperature upstream of the SCR catalyst within the predetermined temperature range:
confirming that a temperature upstream of the particulate replenishment reservoir reaches a temperature threshold.
5. The method of claim 1, further comprising:
receiving an SCR catalyst sulfur poisoning detection request during a regeneration light-off phase of the particulate supplement DPF to perform SCR catalyst sulfur poisoning detection.
6. The method of claim 1, wherein the mass of NOx is sensed by a NOx sensor and the predetermined error value is an error value of the NOx sensor.
7. An SCR catalyst sulfur poisoning detection apparatus, comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for respectively acquiring the mass of nitrogen oxides at the upstream and downstream of an SCR catalyst in a first time period and a second time period in the regeneration process of a particle complementing device and calculating the conversion efficiency of the SCR catalyst in the first time period and the second time period; wherein the conversion efficiency of the SCR catalyst is calculated according to the mass of the nitrogen oxide upstream of the SCR catalyst and the mass of the nitrogen oxide downstream of the SCR catalyst in a corresponding time period when the mass of the nitrogen oxide upstream of the SCR catalyst reaches a preset mass threshold value;
the calculation unit is used for calculating the difference value of the conversion efficiency of the first time period and the conversion efficiency of the second time period, and if the difference value of the conversion efficiencies is larger than a preset error value, the detection result is the sulfur poisoning of the SCR catalyst;
wherein the first time period is a time period in a light-off phase of the particulate recollector regeneration process and the second time period is a time period in a cooling phase of the particulate recollector regeneration process.
8. The apparatus of claim 7, wherein the obtaining unit calculating the conversion efficiency of the SCR catalyst for the first and second periods of time comprises:
the acquiring unit calculates and obtains the difference value between the mass of the nitrogen oxide at the upstream of the SCR catalyst and the mass of the nitrogen oxide at the downstream of the SCR catalyst in a corresponding time period;
the obtaining unit calculates and obtains the mass difference and the mass ratio of the nitrogen oxides at the upstream of the SCR catalyst in the corresponding time period, wherein the mass ratio is the conversion efficiency in the corresponding time period.
9. The apparatus of claim 7, wherein before the obtaining unit obtains the mass of nitrogen oxides upstream and downstream of the SCR catalyst for the first and second periods of time, respectively, during regeneration of the particulate replenisher, the apparatus further comprises:
a first confirming unit for confirming that the detected values of the nitrogen oxide sensors upstream of the SCR catalyst and downstream of the SCR catalyst are valid;
a first holding unit for holding a temperature upstream of the SCR catalyst within a predetermined temperature range;
a second holding unit for holding a concentration of nitrogen oxides upstream of the SCR catalyst within a predetermined concentration range;
and the third maintaining unit is used for maintaining the mass flow of the tail gas within a preset mass flow range.
10. The apparatus according to claim 9, wherein before the first holding unit holds the temperature upstream of the SCR catalyst within the predetermined temperature range, the apparatus further comprises:
a second confirmation unit for confirming that the temperature upstream of the particle complement has reached a temperature threshold.
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| CN113803143B (en) * | 2021-09-02 | 2022-09-23 | 潍柴动力股份有限公司 | DOC sulfur poisoning judgment method and control device with same |
| CN113669143B (en) * | 2021-09-24 | 2022-12-06 | 一汽解放汽车有限公司 | Performance detection method, detection device and medium for tail gas aftertreatment system |
| CN113719338B (en) * | 2021-09-27 | 2023-01-24 | 潍柴动力股份有限公司 | SCR sulfur poisoning degree determining method and device, diesel vehicle and medium |
| CN113756921B (en) * | 2021-09-29 | 2023-01-06 | 潍柴动力股份有限公司 | Method and device for determining sulfur poisoning of SCR system, vehicle and medium |
| CN114592955B (en) * | 2022-03-17 | 2023-12-15 | 潍柴动力股份有限公司 | Method, device, system and storage medium for determining SCR carrier sulfur poisoning |
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