Method and device for determining sulfur poisoning of SCR system, vehicle and medium

文档序号：1933882 发布日期：2021-12-07 浏览：18次中文

阅读说明：本技术 一种scr系统硫中毒确定方法、装置、车辆及介质 (Method and device for determining sulfur poisoning of SCR system, vehicle and medium ) 是由赵德财孙善良于 2021-09-29 设计创作，主要内容包括：本发明实施例公开了一种SCR系统硫中毒确定方法、装置、车辆及介质。该SCR系统硫中毒确定方法包括：获取发动机排气中的上游NOx值和下游NOx值,并按功基窗口计算得到上游NOx比排放值和下游NOx比排放值；确定多个SCR转化效率值,并确定SCR转化效率分布状态；根据多个功基窗口的下游NOx比排放值确定多个相邻功基窗口的比排放平均斜率、多个功基窗口的比排放总斜率以及多个下游NOx比排放值的平均比排放值,并确定SCR下游NOX比排放状态；根据SCR转化效率分布状态和SCR下游NOX比排放状态确定SCR系统是否出现硫中毒故障。以实现对硫中毒进行准确判断,并及时提醒用户对硫中毒进行处理,保持后处理系统性能。(The embodiment of the invention discloses a method, a device, a vehicle and a medium for determining sulfur poisoning of an SCR system. The method for determining the sulfur poisoning of the SCR system comprises the following steps: obtaining an upstream NOx value and a downstream NOx value in engine exhaust, and calculating according to a power base window to obtain an upstream NOx specific emission value and a downstream NOx specific emission value; determining a plurality of SCR conversion efficiency values and determining an SCR conversion efficiency distribution state; determining specific emission average slopes of a plurality of adjacent work base windows, specific emission total slopes of a plurality of work base windows and average specific emission values of a plurality of downstream NOx specific emission values according to the downstream NOx specific emission values of the plurality of work base windows, and determining an SCR downstream NOx specific emission state; and determining whether the SCR system has a sulfur poisoning fault according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state. The method and the device can accurately judge the sulfur poisoning, remind a user of treating the sulfur poisoning in time and keep the performance of the post-treatment system.)

1. An SCR system sulfur poisoning determination method, characterized by comprising:

after determining that the sulfur poisoning fault judgment enabling condition is met through an OBD system of the vehicle, acquiring an upstream NOx value in engine exhaust and a downstream NOx value in the engine exhaust measured by a downstream NOx sensor, and calculating according to a power base window to obtain an upstream NOx specific emission value and a downstream NOx specific emission value;

determining a plurality of SCR conversion efficiency values according to the upstream NOx specific emission value and the downstream NOx specific emission value, and determining an SCR conversion efficiency distribution state according to the plurality of SCR conversion efficiency values;

determining a specific-emission average slope for a plurality of adjacent work-based windows, a specific-emission total slope for a plurality of the work-based windows, and an average specific-emission value for a plurality of the downstream NOx-specific-emission values based on the downstream NOx-specific-emission values for a plurality of the work-based windows, and determining an SCR downstream NOx-specific-emission state based on the specific-emission average slope, the specific-emission total slope, and the average specific-emission value;

and determining whether the SCR system has sulfur poisoning faults according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state.

2. The SCR system sulfur poisoning determination method of claim 1, before determining, by the vehicle OBD system, that the sulfur poisoning fault determination enabling condition is satisfied, further comprising:

acquiring the mass flow of engine exhaust of an aftertreatment system and an SCR upstream temperature value measured by an SCR upstream temperature sensor;

the sulfur poisoning fault judgment enabling condition is that the engine exhaust mass flow is larger than a calibrated engine exhaust mass flow limit value, the SCR upstream temperature value is larger than a calibrated temperature limit value, and a vehicle OBD system determines that NOx emission is not faulty, the downstream NOx sensor is not faulty and the SCR upstream temperature sensor is not faulty.

3. The SCR system sulfur poisoning determination method of claim 2, further comprising, before calculating the upstream NOx specific emission value and the downstream NOx specific emission value in terms of a work base window:

the method comprises the steps of obtaining the engine speed of the vehicle, and determining that the engine speed is in a set engine speed range, the engine exhaust mass flow is in a set engine exhaust mass flow range, and the SCR upstream temperature value is larger than a set temperature range.

4. The SCR system sulfur poisoning determination method of claim 1, wherein determining a SCR downstream NOX specific emission state based on the specific emission average slope, the specific emission total slope, and the average specific emission value comprises:

and if the specific emission average slope is in a preset specific emission average slope threshold range, the specific emission total slope is in a preset specific emission total slope threshold range, and the average specific emission value is greater than a set average specific emission threshold, determining that the downstream NOx specific emission state of the SCR is abnormal.

5. The SCR system sulfur poisoning determination method of claim 1, further comprising, prior to determining an SCR downstream NOX specific emission state based on the specific emission average slope, the specific emission total slope, and the average specific emission value:

determining that the SCR downstream NOx specific emission state is SCR removed if an ith downstream NOx specific emission value determined by the ith work base window is greater than a set downstream NOx specific emission threshold, an average specific emission value of a plurality of downstream NOx specific emission values determined before the ith work base window is less than a first average specific emission value, and an average specific emission value of a plurality of downstream NOx specific emission values determined after the ith work base window is greater than a second average specific emission value;

wherein i is a positive integer greater than 1.

6. The SCR system sulfur poisoning determination method of claim 1, wherein determining whether a SCR system has a sulfur poisoning fault based on the SCR conversion efficiency distribution status and the SCR downstream NOX specific emission status comprises:

and if the SCR conversion efficiency distribution state is poor SCR conversion efficiency distribution and the SCR downstream NOx ratio emission state is abnormal, determining that the SCR system has a sulfur poisoning fault.

7. The SCR system sulfur poisoning determination method of claim 1, further comprising:

and after the sulfur poisoning fault occurs in the SCR system, responding to a high-temperature regeneration request of the vehicle, judging whether the SCR conversion efficiency distribution state is poor in SCR conversion efficiency distribution, if so, setting a regeneration detoxification frequency limit value, and if not, reporting the sulfur poisoning fault.

8. An SCR system sulfur poisoning determination device characterized by comprising:

the specific emission value determining module is used for acquiring an upstream NOx value in engine exhaust and a downstream NOx value in the engine exhaust measured by a downstream NOx sensor after determining that the sulfur poisoning fault judgment enabling condition is met through an OBD system of the vehicle, and calculating according to a power base window to obtain an upstream NOx specific emission value and a downstream NOx specific emission value;

the SCR conversion efficiency distribution state determining module is used for determining a plurality of SCR conversion efficiency values according to the upstream NOx ratio emission value and the downstream NOx ratio emission value and determining an SCR conversion efficiency distribution state according to the plurality of SCR conversion efficiency values;

an SCR downstream NOx specific emission state determination module to determine a specific emission average slope for a plurality of adjacent work based windows, a specific emission total slope for a plurality of the work based windows, and an average specific emission value for a plurality of the downstream NOx specific emission values based on the downstream NOx specific emission values for the plurality of work based windows, and to determine an SCR downstream NOx specific emission state based on the specific emission average slope, the specific emission total slope, and the average specific emission value;

and the sulfur poisoning fault determining module is used for determining whether the SCR system has a sulfur poisoning fault according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state.

9. A vehicle, characterized in that the vehicle comprises:

one or more processors;

storage means for storing one or more programs;

when executed by the one or more processors, cause the one or more processors to implement the SCR system sulfur poisoning determination method of any one of claims 1-7.

10. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the SCR system sulfur poisoning determination method according to any one of claims 1 to 7.

Technical Field

The embodiment of the invention relates to the technical field of aftertreatment control, in particular to a method, a device, a vehicle and a medium for determining sulfur poisoning of an SCR system.

Background

The non-road four-stage diesel engine has higher requirements on diesel oil, and the sulfur content of oil products in domestic markets is different, so that part of users still use inferior fuel oil with extremely high sulfur content in the third country and the fourth country in order to save cost in the actual use process.

The use of high-sulfur fuel oil by a diesel engine can cause a large amount of sulfides in tail gas to cause serious pollution to an after-treatment system, particularly to an SCR (Selective Catalytic Reduction) of the after-treatment system of the diesel engine, so that a catalyst of the after-treatment system is poisoned, and the conversion efficiency of the SCR system to tail gas nitrogen oxides after sulfur poisoning is reduced, thereby causing the emission to exceed the standard; in addition, the after-treatment system can cause irreversible failure after long-time poisoning, and the after-treatment failure caused by sulfur poisoning frequently occurs in the market, so that certain loss is brought to customers and enterprises.

Disclosure of Invention

The embodiment of the invention provides a method, a device, a vehicle and a medium for determining sulfur poisoning of an SCR system, so as to accurately judge the sulfur poisoning, remind a user of treating the sulfur poisoning in time and keep the performance of a post-treatment system.

In a first aspect, an embodiment of the present invention provides a method for determining sulfur poisoning of an SCR system, where the method for determining sulfur poisoning of an SCR system includes:

and determining whether the SCR system has sulfur poisoning faults according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state.

Further, before it is determined by the vehicle OBD system that the sulfur poisoning failure determination enabling condition is satisfied, the method further includes:

acquiring the mass flow of engine exhaust of an aftertreatment system and an SCR upstream temperature value measured by an SCR upstream temperature sensor;

Further, before calculating the upstream NOx specific emission value and the downstream NOx specific emission value according to the work base window, the method further includes:

Further, before determining the SCR downstream NOx specific emission state according to the specific emission average slope, the specific emission total slope and the average specific emission value, the method further comprises the following steps:

wherein i is a positive integer greater than 1.

Further, determining whether a sulfur poisoning fault occurs in the SCR system according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state comprises:

Further, the method for determining sulfur poisoning of the SCR system further includes:

In a second aspect, an embodiment of the present invention further provides an SCR system sulfur poisoning determination device, including:

In a third aspect, an embodiment of the present invention further provides a vehicle, including:

one or more processors;

a storage device for storing a plurality of programs,

when at least one of the plurality of programs is executed by the one or more processors, the one or more processors are caused to implement a method for determining sulfur poisoning of an SCR system provided in an embodiment of the first aspect of the present invention.

In a fourth aspect, the embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the method for determining sulfur poisoning of an SCR system provided in the embodiment of the first aspect of the present invention.

According to the technical scheme of the embodiment of the invention, after the condition that sulfur poisoning fault judgment enabling conditions are met is determined by an OBD system of the vehicle, an upstream NOx value in engine exhaust and a downstream NOx value in the engine exhaust measured by a downstream NOx sensor are obtained, and an upstream NOx specific emission value and a downstream NOx specific emission value are obtained by calculation according to a power base window; determining a plurality of SCR conversion efficiency values according to the upstream NOx specific emission value and the downstream NOx specific emission value, and determining an SCR conversion efficiency distribution state according to the plurality of SCR conversion efficiency values; determining a specific-emission average slope for a plurality of adjacent work-based windows, a specific-emission total slope for a plurality of the work-based windows, and an average specific-emission value for a plurality of the downstream NOx-specific-emission values based on the downstream NOx-specific-emission values for a plurality of the work-based windows, and determining an SCR downstream NOx-specific-emission state based on the specific-emission average slope, the specific-emission total slope, and the average specific-emission value; and determining whether the SCR system has sulfur poisoning faults according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state. The problem that the emission of an SCR system exceeds the standard after sulfur poisoning and the aftertreatment system is irreversibly disabled after long-time poisoning to cause loss is solved, so that accurate judgment on sulfur poisoning is realized, a user is timely reminded of treating sulfur poisoning, and the performance of the aftertreatment system is kept.

Drawings

Fig. 1 is a flowchart of a method for determining sulfur poisoning of an SCR system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a diesel aftertreatment system provided in accordance with an embodiment of the invention;

FIG. 3 is a flowchart illustrating a method for determining sulfur poisoning of an SCR system according to a second embodiment of the present invention;

FIG. 4 is a graphical illustration of a SCR conversion efficiency distribution provided by an embodiment of the present invention;

FIG. 5 is a graphical illustration of NOx specific emission conditions downstream of the SCR provided by an embodiment of the present invention;

fig. 6 is a structural diagram of a sulfur poisoning determination apparatus of an SCR system according to a third embodiment of the present invention;

fig. 7 is a schematic hardware structure diagram of a vehicle according to a fourth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.

It should be further noted that, for the convenience of description, only some but not all of the relevant aspects of the present invention are shown in the drawings. Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart may describe the operations (or steps) as a sequential process, many of the operations can be performed in parallel, concurrently or simultaneously. In addition, the order of the operations may be re-arranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, and the like.

Example one

Fig. 1 is a flowchart of a method for determining sulfur poisoning of an SCR system according to an embodiment of the present invention, where the method is applicable to a case where a sulfur poisoning determination is performed based on a statistical distribution of SCR conversion efficiency of the SCR system and a downstream NOx ratio emission change rule. The method for determining the sulfur poisoning of the SCR system specifically comprises the following steps:

and S110, after determining that the sulfur poisoning fault judgment enabling condition is met through an OBD system of the vehicle, acquiring an upstream NOx value in engine exhaust and a downstream NOx value in the engine exhaust measured by a downstream NOx sensor, and calculating according to a power base window to obtain an upstream NOx specific emission value and a downstream NOx specific emission value.

Fig. 2 is a schematic structural diagram of a Diesel engine aftertreatment system according to an embodiment of the present invention, referring to fig. 2, engine exhaust sequentially passes through a DOC (Diesel Oxidation Catalyst), a DPF (Diesel Particulate Filter), and an SCR (Selective Catalytic Reduction), in this embodiment, only the SCR is shown, where reference numeral 1 is an SCR upstream temperature sensor, reference numeral 2 is an upstream NOx sensor, reference numeral 3 is a downstream NOx sensor, reference numeral 4 is an engine control unit ECU, and the engine control unit ECU is configured to complete acquisition and storage of parameters of the sensors, and storage and transmission of limits corresponding to the parameters.

It should be noted that, in the present embodiment, the upstream NOx sensor is optional, and when the upstream NOx sensor is provided in the diesel aftertreatment system, the upstream NOx sensor is located upstream of the SCR, the SCR is used for eliminating nitrogen oxides in the exhaust gas of the engine, and the upstream NOx sensor is used for measuring an upstream NOx value in the exhaust gas of the engine. If no upstream NOx sensor is provided in the diesel aftertreatment system, the upstream NOx value in the engine exhaust may be replaced by a NOx model value.

A downstream NOx sensor is located downstream of the SCR for measuring a downstream NOx value in the engine exhaust.

With continued reference to fig. 2, specifically, after it is determined by the vehicle OBD system that the sulfur poisoning failure determination enabling condition is satisfied, an upstream NOx value in the engine exhaust flowing into the aftertreatment system is measured by the upstream NOx sensor, or, as the upstream NOx value in the engine exhaust, a NOx model value is used, and further, a downstream NOx value in the engine exhaust flowing into the aftertreatment system is measured by the downstream NOx sensor.

On the basis of the above embodiment, before determining, by the vehicle OBD system, that the sulfur poisoning failure determination enabling condition is satisfied, the method further includes: acquiring the mass flow of engine exhaust of an aftertreatment system and an SCR upstream temperature value measured by an SCR upstream temperature sensor;

with continued reference to fig. 2, specifically, before it is determined by the vehicle OBD system that the sulfur poisoning failure determination enabling condition is satisfied, the engine exhaust mass flow of the aftertreatment system and the SCR upstream temperature value measured by the SCR upstream temperature sensor are obtained by the engine control unit ECU, so as to determine whether the aftertreatment system satisfies the sulfur poisoning failure determination enabling condition by the vehicle OBD system according to the above parameters.

The sulfur poisoning fault judgment enabling condition is that the engine exhaust mass flow is larger than a calibrated engine exhaust mass flow limit value, the SCR upstream temperature value is larger than a calibrated temperature limit value, and a vehicle OBD system determines that NOx emission is not faulty, the downstream NOx sensor is not faulty and the SCR upstream temperature sensor is not faulty.

The vehicle OBD system is a vehicle-mounted diagnosis system and is used for monitoring the running condition of an engine and whether tail gas exceeds the standard or not and sending out warning.

On the basis of the above embodiment, before calculating the upstream NOx specific emission value and the downstream NOx specific emission value in terms of the work base window, the calculation conditions for determining the work base window include: the method comprises the steps of obtaining the engine speed of the vehicle, and determining that the engine speed is in a set engine speed range, the engine exhaust mass flow is in a set engine exhaust mass flow range, and the SCR upstream temperature value is larger than a set temperature range.

The accumulated work of the engine is obtained by continuously integrating the power of the engine, and the accumulated work P of the engine reaches the calibrated maximum work amount Pmax and is used as a power base window.

On the basis, the upstream NOx value of one power base window is divided by the calibrated maximum work amount Pmax, and the upstream NOx specific emission value is calculated, and the downstream NOx value of one power base window is divided by the calibrated maximum work amount Pmax, and the downstream NOx specific emission value is calculated.

S120, determining a plurality of SCR conversion efficiency values according to the upstream NOx specific emission value and the downstream NOx specific emission value, and determining an SCR conversion efficiency distribution state according to the plurality of SCR conversion efficiency values.

Wherein, a work base window can obtain an SCR conversion efficiency value through calculation of an upstream NOx specific emission value N1 and a downstream NOx specific emission value N2 of the work base window, k SCR conversion efficiency values are calculated by k work base windows, and k is a positive integer larger than 1.

It will be appreciated that k is set taking into account the diesel vehicle model and the corresponding engine displacement, typically the greater the engine displacement, the greater the value of k.

The SCR conversion efficiency value is calculated as (upstream NOx ratio emission value N1-downstream NOx ratio emission value N2)/upstream NOx ratio emission value N1.

Specifically, the efficiency distribution of k SCR conversion efficiency values is counted, and the calculated ratio of the k SCR conversion efficiency values SCRef is counted at intervals or step lengths of 10%, or other intervals or step lengths.

If the proportion of k SCR conversion efficiency values SCRef which are smaller than the minimum SCR conversion efficiency value SCRefmin exceeds a set proportion value, the SCR conversion efficiency distribution state is judged to be that the SCR conversion efficiency is poor as a whole, and at the moment, the SCR conversion efficiency distribution state SCRef _ st is set to be 1 through an ECU; if the proportion of the k SCR conversion efficiency values SCRef which is larger than the maximum SCR conversion efficiency value SCRefmax exceeds the set proportion value, the SCR conversion efficiency distribution state is judged to be that the SCR conversion efficiency is overall better, and at the moment, the SCR conversion efficiency distribution state SCRef _ st is set to be 2 through the ECU.

It should be noted that the minimum SCR conversion efficiency value scrfmin, the maximum SCR conversion efficiency value scrfmax and the set ratio are all selected and set by those skilled in the art according to actual determination conditions, and this embodiment does not limit this.

S130, determining specific emission average slopes of a plurality of adjacent work base windows, specific emission total slopes of a plurality of work base windows and average specific emission values of a plurality of downstream NOx specific emission values according to the downstream NOx specific emission values of the work base windows, and determining an SCR downstream NOx specific emission state according to the specific emission average slopes, the specific emission total slopes and the average specific emission values.

During the sulfur poisoning process of the SCR system, the downstream NOx specific emission of the SCR is gradually deteriorated, the SCR conversion efficiency is gradually reduced as the poisoning degree is deepened, and the downstream NOx specific emission is gradually increased. On the basis of the downstream NOx specific emission values of a plurality of the work base windows, specific emission average slopes of a plurality of adjacent work base windows, specific emission total slopes of a plurality of the work base windows and average specific emission values of a plurality of the downstream NOx specific emission values are determined.

Further, determining the SCR downstream NOx specific emission state according to the specific emission average slope, the specific emission total slope and the average specific emission value comprises: and if the specific emission average slope is in the preset specific emission average slope threshold range, the specific emission total slope is in the preset specific emission total slope threshold range, and the average specific emission value is greater than the set average specific emission threshold, determining that the SCR downstream NOx specific emission state is abnormal, and setting the SCR downstream NOx specific emission state SCRM _ st to be 1 through the ECU.

On the basis of the above embodiment, considering that the SCR is removed, the downstream NOx specific emission will be continuously larger, and before determining the SCR downstream NOx specific emission state according to the specific emission average slope, the specific emission total slope, and the average specific emission value, further comprising: if the ith downstream NOx specific emission value determined by the ith power base window is larger than the set downstream NOx specific emission threshold value, the average specific emission value of a plurality of downstream NOx specific emission values determined before the ith power base window is smaller than the first average specific emission value, and the average specific emission value of a plurality of downstream NOx specific emission values determined after the ith power base window is larger than the second average specific emission value, determining that the SCR downstream NOx specific emission state is SCR removal, and at the moment, setting the SCR downstream NOx specific emission state SCRM _ st to 2 through the ECU, and carrying out SCR removal fault alarm by the vehicle OBD system; wherein i is a positive integer greater than 1.

It should be noted that the downstream NOx specific emission threshold Nmax is set as an upper limit value of the emission overrun, the first average specific emission value Nmin is set to be smaller than an OBD system alarm limit value (for example, 4g/kw.h) required by the emission regulations, the second average specific emission value Nmax is an upper limit value of the emission overrun, and the ECU calculates and stores the specific emission value for each power base window.

And S140, determining whether the SCR system has a sulfur poisoning fault according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state.

On the basis of the embodiment, the step of determining whether the SCR system has the sulfur poisoning fault according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state comprises the following steps: and if the SCR conversion efficiency distribution state is poor SCR conversion efficiency distribution and the SCR downstream NOx ratio emission state is abnormal, determining that the SCR system has a sulfur poisoning fault.

When the SCR conversion efficiency distribution state SCRef _ st is set to 1 by the ECU and the SCR downstream NOx specific emission state SCRM _ st is set to 1 by the ECU, the SCR efficiency distribution is poor and the SCR downstream NOx specific emission state is abnormal, and at the moment, the possibility of sulfur poisoning faults of the SCR system is high.

Further, the method for determining sulfur poisoning of the SCR system further includes: and after the sulfur poisoning fault occurs in the SCR system, responding to a high-temperature regeneration request of the vehicle, judging whether the SCR conversion efficiency distribution state is poor in SCR conversion efficiency distribution, if so, setting a regeneration detoxification frequency limit value, and if not, reporting the sulfur poisoning fault.

The ECU judges and reports that the post-processing system has sulfur poisoning faults, and automatically enters regeneration detoxification in response to the high-temperature regeneration request to perform high-temperature detoxification.

Specifically, at this time, the SCR system has a high possibility of sulfur poisoning failure, the vehicle generates a high-temperature regeneration request, and performs SCR desulfurization and detoxification through a sustained high temperature for a certain time (for example, setting the DPF or SCR temperature to 550 ℃, and continuing for 30min), and if the SCR conversion efficiency distribution state is that the SCR conversion efficiency distribution is poor after high-temperature regeneration, a regeneration detoxification frequency limit is set, and desulfurization regeneration is not performed in a short period of time; if the SCR conversion efficiency distribution state SCRef _ st is set to be 2, namely the SCR conversion efficiency is integrally good, the SCR system is considered to have a sulfur poisoning fault, the sulfur poisoning fault is reported to give a sulfur poisoning alarm, the high-temperature regeneration can also avoid continuous deep poisoning, and the service life of the SCR system is prolonged.

Example two

Fig. 3 is a flowchart of a method for determining sulfur poisoning of an SCR system according to a second embodiment of the present invention, which is optimized based on the second embodiment.

Correspondingly, the method of the embodiment specifically includes:

s210, acquiring an engine exhaust mass flow of the aftertreatment system and an SCR upstream temperature value measured by an SCR upstream temperature sensor.

And S211, determining that the sulfur poisoning fault judgment enabling condition is met through an OBD system of the vehicle.

After the vehicle is started, the engine exhaust mass flow M is determined to be larger than a calibrated engine exhaust mass flow limit value Mmin, and the SCR upstream temperature value Tscr is larger than a calibrated temperature limit value Tmin. The calibrated engine exhaust mass flow limit Mmin and the calibrated temperature limit Tmin are selected and set by a person skilled in the art according to actual determination conditions, and the embodiment does not limit the above.

The determination of no fault in NOx emissions by the vehicle OBD system, NOx emissions related to faults such as urea injection system faults, urea concentration off-specification faults, ammonia slip faults, etc. is made where no other faults affecting NOx emissions are determined by the vehicle OBD system.

S212, acquiring an upstream NOx value in the engine exhaust and a downstream NOx value in the engine exhaust measured by a downstream NOx sensor.

S213, determining whether the calculation condition of the function base window is satisfied, if yes, performing step S214, and if no, performing step S211.

Specifically, before determining whether the calculation condition of the power base window is met, the engine speed of the vehicle is obtained, and on the basis, the calculation condition of the power base window is to determine that the engine speed is in a set engine speed range, the engine exhaust mass flow is in a set engine exhaust mass flow range, and the SCR upstream temperature value is greater than a set temperature range.

And S214, calculating an upstream NOx specific emission value and a downstream NOx specific emission value according to the work base window.

S215, determining a plurality of SCR conversion efficiency values according to the upstream NOx specific emission value and the downstream NOx specific emission value, and determining an SCR conversion efficiency distribution state according to the plurality of SCR conversion efficiency values.

Fig. 4 is a schematic graph of an SCR conversion efficiency distribution state provided in an embodiment of the present invention, and referring to fig. 4, efficiency distribution of k SCR conversion efficiency values is counted, if an occupation ratio smaller than a minimum SCR conversion efficiency value scrfmin among the k SCR conversion efficiency values SCRef exceeds a set occupation ratio, it is determined that the SCR conversion efficiency distribution state is that the SCR conversion efficiency is overall poor, and if an occupation ratio larger than a maximum SCR conversion efficiency value scrfmax among the k SCR conversion efficiency values SCRef exceeds the set occupation ratio, it is determined that the SCR conversion efficiency distribution state is that the SCR conversion efficiency is overall good.

S216, determining specific emission average slopes of a plurality of adjacent work base windows, specific emission total slopes of a plurality of work base windows and average specific emission values of a plurality of downstream NOx specific emission values according to the downstream NOx specific emission values of the plurality of work base windows.

S217, determining the SCR downstream NOx specific emission state according to the specific emission average slope, the specific emission total slope and the average specific emission value.

During sulfur poisoning, the downstream NOx specific emission of the SCR is gradually deteriorated, the SCR conversion efficiency is gradually reduced along with the increase of the poisoning degree, and the downstream NOx specific emission is gradually increased. Specifically, the total slope of the specific emissions of k consecutive work base windows and the average slope of the adjacent windows are all within a certain range, for example, Ni is the specific emission value of the ith work base windowX1 ═ N2-N1)/1 is the ratio discharge slope of N1 to N2,specific emission slopes N1 to Nk, if the specific emission average slope x _ pj is within a preset specific emission average slope threshold range, i.e., theAnd the specific exhaust gross slope x _ z is within a preset specific exhaust gross slope threshold range, i.e.And if the average specific emission value is larger than the set average specific emission threshold, determining that the downstream NOx specific emission state of the SCR is abnormal after the 3 conditions are met.

S218, judging whether the SCR downstream NOx specific emission state is abnormal or not, if so, executing step S219, otherwise, executing step S220.

S219, determining that the downstream NOx ratio emission state of the SCR is that the SCR is removed, and reporting an SCR removal fault.

When the SCR is removed, the SCR conversion efficiency is suddenly changed, namely, in k power base windows, the specific emission of one power base window is abnormally large, fig. 5 is a graphical representation of specific NOX emission conditions downstream of the SCR provided by an embodiment of the present invention, see fig. 5, after the work base window 8 in the figure, as the SCR is removed, the downstream NOx will continue to be larger than the emissions, i.e. the ith downstream NOx specific emission value determined by the ith said work base window is greater than the set downstream NOx specific emission threshold Nmax, and the average specific emission value of the plurality of downstream NOx specific emission values determined before the ith said work base window is less than the first average specific emission value Nmin, and the average specific emission value of the plurality of downstream NOx specific emission values determined after the ith said work base window is greater than the second average specific emission value Nmax, determining that the downstream NOx specific emission state of the SCR is SCR removed, and carrying out SCR removal fault alarm by the vehicle OBD; wherein i is a positive integer greater than 1.

It will be appreciated that the off-road four-phase vehicle OBD system primarily monitors whether the SCR is removed. When vehicles use high sulfur oil, the SCR conversion efficiency gradually deteriorates, with a clear difference from the SCR efficiency change caused by directly removing the SCR. The invention mainly monitors the change of SCR conversion efficiency to distinguish SCR removal and sulfur poisoning, and takes certain alarming and protecting measures after sulfur poisoning.

S220, if the SCR conversion efficiency distribution state is poor SCR conversion efficiency distribution and the SCR downstream NOx ratio emission state is abnormal, determining that the SCR system has sulfur poisoning faults.

And S221, responding to the high-temperature regeneration request of the vehicle, and performing high-temperature regeneration.

S222, determining whether the SCR conversion efficiency distribution state is the SCR conversion efficiency distribution difference, if so, executing step S223, and if not, executing step S224.

And S223, setting a regeneration detoxification frequency limit value, and not performing desulfurization regeneration in a short period.

S224, a sulfur poisoning failure is reported, and step S211 is executed.

Specifically, the sulfur poisoning failure is reported, and the sulfur poisoning failure is cured on a time basis.

According to the technical scheme of the embodiment of the invention, sulfur poisoning judgment is carried out by taking the distribution of SCR conversion efficiency as a key factor through the characteristics of sulfur poisoning of an SCR system and SCR conversion efficiency of normal post-treatment; meanwhile, SCR removal faults and sulfur poisoning faults required by non-road four-stage regulations are distinguished, and the sulfur poisoning and the SCR removal of an SCR system are distinguished according to the characteristic of the downstream NOx specific emission change of the SCR. If the characteristics that SCR conversion efficiency distribution is concentrated in a low-efficiency region and the specific emission degradation rate of NOx at the downstream of SCR is in a certain range are met, suspicion of SCR system sulfur poisoning is high, then regeneration desulfurization is triggered, and if the SCR conversion efficiency recovers after regeneration, the SCR system sulfur poisoning is judged and a sulfur poisoning alarm is carried out.

The method has the advantages that after the vehicle uses the high-sulfur fuel oil, the SCR system sulfur poisoning judgment and detoxification are carried out before the emission of the high-sulfur fuel oil exceeds the standard, the vehicle torsion limitation and fault lamp lightening are avoided, the SCR system sulfur poisoning accurate judgment can be carried out based on the SCR conversion efficiency statistical distribution condition of the SCR system after sulfur poisoning and the SCR downstream NOx specific emission change rule, a high-temperature desulfurization regeneration method is further adopted, the emission durability of the system is favorably realized, the irreversible deep poisoning is avoided, the performance of a post-treatment system is kept, meanwhile, an additional sensor is not needed, and the cost is saved.

EXAMPLE III

Fig. 6 is a structural diagram of a sulfur poisoning determination device of an SCR system according to a third embodiment of the present invention, which is applicable to a case of determining sulfur poisoning based on a statistical distribution of SCR conversion efficiency of the SCR system and a downstream NOx specific emission change rule.

As shown in fig. 6, the SCR system sulfur poisoning determination device includes: a specific emission value determination module 610, an SCR conversion efficiency distribution status determination module 620, an SCR downstream NOx specific emission status determination module 630, and a sulfur poisoning failure determination module 640, wherein:

the specific emission value determining module 610 is used for acquiring an upstream NOx value in engine exhaust and a downstream NOx value in the engine exhaust measured by a downstream NOx sensor after determining that the sulfur poisoning fault judgment enabling condition is met through an OBD system of the vehicle, and calculating according to a power base window to obtain an upstream NOx specific emission value and a downstream NOx specific emission value;

an SCR conversion efficiency distribution determination module 620, configured to determine a plurality of SCR conversion efficiency values according to the upstream NOx specific emission value and the downstream NOx specific emission value, and determine an SCR conversion efficiency distribution according to the plurality of SCR conversion efficiency values;

an SCR downstream NOx specific emission state determination module 630 configured to determine a specific emission average slope for a plurality of adjacent work base windows, a specific emission global slope for a plurality of the work base windows, and an average specific emission value for a plurality of the downstream NOx specific emission values based on the downstream NOx specific emission values for a plurality of the work base windows, and to determine an SCR downstream NOx specific emission state based on the specific emission average slope, the specific emission global slope, and the average specific emission value;

a sulfur poisoning failure determination module 640 for determining whether a sulfur poisoning failure of the SCR system occurs based on the SCR conversion efficiency distribution status and the SCR downstream NOx specific emission status.

The SCR system sulfur poisoning determination apparatus of this embodiment obtains an upstream NOx value in engine exhaust and a downstream NOx value in engine exhaust measured by a downstream NOx sensor after determining that a sulfur poisoning failure determination enabling condition is satisfied by a vehicle OBD system, and calculates an upstream NOx specific emission value and a downstream NOx specific emission value according to a power base window; determining a plurality of SCR conversion efficiency values according to the upstream NOx specific emission value and the downstream NOx specific emission value, and determining an SCR conversion efficiency distribution state according to the plurality of SCR conversion efficiency values; determining a specific-emission average slope for a plurality of adjacent work-based windows, a specific-emission total slope for a plurality of the work-based windows, and an average specific-emission value for a plurality of the downstream NOx-specific-emission values based on the downstream NOx-specific-emission values for a plurality of the work-based windows, and determining an SCR downstream NOx-specific-emission state based on the specific-emission average slope, the specific-emission total slope, and the average specific-emission value; and determining whether the SCR system has sulfur poisoning faults according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state. The problem that the emission of an SCR system exceeds the standard after sulfur poisoning and the aftertreatment system is irreversibly disabled after long-time poisoning to cause loss is solved, so that accurate judgment on sulfur poisoning is realized, a user is timely reminded of treating sulfur poisoning, and the performance of the aftertreatment system is kept.

On the basis of the foregoing embodiments, the SCR system sulfur poisoning determination device further includes:

the data acquisition module is used for acquiring the mass flow of the exhaust gas of the engine of the aftertreatment system and an SCR upstream temperature value measured by an SCR upstream temperature sensor;

On the basis of the foregoing embodiments, the SCR system sulfur poisoning determination device further includes:

and the power base window condition calculation module is used for acquiring the engine rotating speed of the vehicle and determining that the engine rotating speed is in a set engine rotating speed range, the engine exhaust mass flow is in a set engine exhaust mass flow range, and the SCR upstream temperature value is greater than the set temperature range.

On the basis of the above embodiments, the SCR downstream NOX specific emission state determination module 630 is specifically configured to:

On the basis of the foregoing embodiments, the SCR system sulfur poisoning determination device further includes:

an SCR removed determining module, configured to determine that an SCR downstream NOx specific emission state is SCR removed if an ith downstream NOx specific emission value determined by the ith work base window is greater than a set downstream NOx specific emission threshold, an average specific emission value of a plurality of downstream NOx specific emission values determined before the ith work base window is less than a first average specific emission value, and an average specific emission value of a plurality of downstream NOx specific emission values determined after the ith work base window is greater than a second average specific emission value;

wherein i is a positive integer greater than 1.

On the basis of the foregoing embodiments, the sulfur poisoning failure determination module 640 is specifically configured to:

On the basis of the foregoing embodiments, the SCR system sulfur poisoning determination device further includes:

and the regeneration judging module is used for responding to a high-temperature regeneration request of the vehicle after the sulfur poisoning fault occurs in the SCR system, judging whether the SCR conversion efficiency distribution state is an SCR conversion efficiency distribution difference, if so, setting a regeneration detoxification frequency limit value, and if not, reporting the sulfur poisoning fault.

The SCR system sulfur poisoning determination apparatus provided in each of the above embodiments may execute the SCR system sulfur poisoning determination method provided in any of the embodiments of the present invention, and has a functional module corresponding to the execution of the SCR system sulfur poisoning determination method and a beneficial effect.

Example four

Fig. 7 is a schematic structural diagram of a vehicle according to a fourth embodiment of the present invention, as shown in fig. 7, the vehicle includes a processor 710, a memory 720, an input device 730, and an output device 740; the number of processors 710 in the vehicle may be one or more, and one processor 710 is taken as an example in fig. 7; the processor 710, memory 720, input device 730, and output device 740 in the vehicle may be connected by a bus or other means, such as by a bus in fig. 7.

The memory 720 may be used as a computer readable storage medium for storing software programs, computer executable programs, and modules, such as program instructions/modules corresponding to the SCR system sulfur poisoning determination method in embodiments of the present invention (e.g., the specific emission value determination module 610, the SCR conversion efficiency distribution state determination module 620, the SCR downstream NOX specific emission state determination module 630, and the sulfur poisoning fault determination module 640 in the SCR system sulfur poisoning determination device). The processor 710 executes various functional applications and data processing of the vehicle, i.e., implements the SCR system sulfur poisoning determination method described above, by executing software programs, instructions, and modules stored in the memory 720.

The memory 720 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application program required for at least one function; the storage data area may store data created according to the use of the terminal, and the like. Further, the memory 720 may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some examples, the memory 720 may further include memory located remotely from the processor 710, which may be connected to the vehicle via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The input device 730 may be used to receive input numeric or character information and generate key signal inputs related to user settings and function control of the vehicle. The output device 740 may include a display device such as a display screen.

EXAMPLE five

An embodiment of the present invention also provides a storage medium containing computer-executable instructions, which when executed by a computer processor, are configured to perform a method for determining sulfur poisoning of an SCR system, the method comprising:

and determining whether the SCR system has sulfur poisoning faults according to the SCR conversion efficiency distribution state and the SCR downstream NOx specific emission state.

Of course, the storage medium provided by the embodiment of the present invention contains computer-executable instructions, and the computer-executable instructions are not limited to the operations of the method described above, and may also execute the relevant operations in the method for determining sulfur poisoning in an SCR system provided by any embodiment of the present invention.

From the above description of the embodiments, it is obvious for those skilled in the art that the present invention can be implemented by software and necessary general hardware, and certainly, can also be implemented by hardware, but the former is a better embodiment in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as a floppy disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a FLASH Memory (FLASH), a hard disk or an optical disk of a computer, and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device) to execute the methods according to the embodiments of the present invention.

It should be noted that, in the embodiment of the SCR system sulfur poisoning determination apparatus, the included units and modules are only divided according to the functional logic, but are not limited to the above division as long as the corresponding functions can be realized; in addition, specific names of the functional units are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present invention.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

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Method and device for determining sulfur poisoning of SCR system, vehicle and medium

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