CN117552876A - EGR flow control method, device and equipment - Google Patents
EGR flow control method, device and equipment Download PDFInfo
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- CN117552876A CN117552876A CN202311520006.7A CN202311520006A CN117552876A CN 117552876 A CN117552876 A CN 117552876A CN 202311520006 A CN202311520006 A CN 202311520006A CN 117552876 A CN117552876 A CN 117552876A
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- 238000002485 combustion reaction Methods 0.000 description 4
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
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- 238000010248 power generation Methods 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/0047—Controlling exhaust gas recirculation [EGR]
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
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Abstract
The application discloses an EGR flow control method, device and equipment, which are used for solving the problems that inaccurate flow deviation fault results are caused by inaccurate difference values of EGR actual flow and EGR required flow in the related technology, and the control of an engine on an EGR system is affected. After determining the difference value between the actual flow of the EGR and the required flow of the EGR, judging the authenticity of the current flow difference value through knock intensity, and if the actual flow of the EGR is determined to be inaccurate, correcting a fault diagnosis threshold value through a threshold value correction factor corresponding to the current knock intensity, so that the accuracy of fault diagnosis under the working condition is improved, and fault false alarm is prevented; the required EGR rate is corrected by the EGR rate correction factor corresponding to the current knock intensity, so that the problem that the engine performance and reliability are reduced due to inaccurate control of an EGR system caused by inaccurate EGR flow is solved, and accurate control of the EGR flow is realized.
Description
Technical Field
The application relates to the technical field of automobiles, in particular to an EGR flow control method, an EGR flow control device and EGR flow control equipment.
Background
Currently, EGR (Exhaust Gas Recirculation ) technology is applied in natural gas engines primarily for the purpose of reducing the combustion temperature and the tendency of knocking of the engine and secondarily for improving the NOx emission level of the engine; during use, regulations require monitoring of EGR flow in order to protect the engine and meet emissions specifications.
In the related art, the difference value between the actual EGR flow and the required EGR flow calculated by an ECU (Electronic Control Unit, an electronic controller unit) is compared with a preset fault diagnosis threshold value to determine whether a flow deviation fault exists or not, and the torque output of an engine is limited to reduce the load of the engine after the flow deviation fault exists; however, in the actual use process, the problems of aging of an EGR valve, poor production consistency of the EGR valve, signal drift or other anomalies of related sensors (such as an upstream pressure sensor, a downstream pressure sensor and a position feedback sensor) of an EGR system and the like exist, at this moment, the actual EGR flow calculated by the ECU is distorted, and the difference between the actual EGR flow and the required EGR flow is inaccurate, so that the result of flow deviation fault is inaccurate, and meanwhile, the inaccuracy of the actual EGR flow also affects the normal EGR system control of the engine, thereby affecting the performance and reliability of the engine.
Disclosure of Invention
The purpose of the application is to provide an EGR flow control method, an EGR flow control device and EGR flow control equipment, which are used for solving the problems that inaccurate flow deviation fault results are caused by inaccurate difference values of EGR actual flow and EGR required flow in the related technology, and the control of an EGR system is influenced by an engine.
In a first aspect, the present application provides an EGR flow control method, the method comprising:
determining a flow difference between the EGR actual flow and the EGR demand flow;
comparing the flow difference with a preset flow difference threshold, and comparing the current knock intensity of the engine with a preset knock intensity threshold;
if the determined comparison result indicates that the EGR actual flow is inaccurate, correcting a fault diagnosis threshold value based on a threshold value correction factor corresponding to the current knock intensity of the engine, and correcting a required EGR rate based on an EGR rate correction factor corresponding to the current knock intensity; the fault diagnosis threshold is used for determining a fault level based on the flow difference value; the demanded EGR rate is used to control the amount of exhaust gas entering the cylinders via EGR.
In one possible embodiment, before determining the flow difference between the actual EGR flow and the required EGR flow, the method further includes:
determining that the vehicle meets the safe working condition;
wherein the safe operating conditions include all of the following:
the engine speed is greater than or equal to a preset speed threshold;
the intake pressure is greater than or equal to a preset pressure threshold;
the engine control system is free of EGR system faults and knock faults;
the gas composition adaptive factor is in a preset range.
In one possible implementation manner, if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold value and the current knock intensity is greater than or equal to a preset first knock intensity threshold value, the EGR actual flow is characterized as inaccurate;
and if the comparison result shows that the flow difference is smaller than or equal to a preset second flow difference threshold value and the current knock intensity is smaller than or equal to a preset second knock intensity threshold value, the actual flow of the EGR is not accurate.
In one possible implementation manner, if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold, and the current knock intensity is greater than or equal to a preset first knock intensity threshold;
the correcting the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity comprises the following steps:
obtaining a threshold value increase factor for increasing a fault detection threshold value according to the corresponding relation between the knock intensity and the threshold value increase factor, and obtaining a corrected fault detection threshold value based on the threshold value increase factor; the threshold correction factor includes a threshold increase factor;
the correcting the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity includes:
according to the corresponding relation between the knocking intensity and the EGR rate increasing factor, an EGR rate increasing factor for increasing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate increasing factor; the EGR rate correction factor includes an EGR rate increase factor.
In one possible implementation manner, if the comparison result is that the flow difference is less than or equal to a preset second flow difference threshold value, and the current knock intensity is less than or equal to a preset second knock intensity threshold value;
the correcting the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity comprises the following steps:
according to the corresponding relation between the knock intensity and the threshold reduction factor, obtaining a threshold reduction factor for reducing the fault detection threshold, and obtaining a corrected fault detection threshold based on the threshold reduction factor; the threshold correction factor includes a threshold reduction factor;
the correcting the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity includes:
according to the corresponding relation between the knocking intensity and the EGR rate reduction factor, an EGR rate reduction factor for reducing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate reduction factor; the EGR rate correction factor includes an EGR rate reduction factor.
In one possible embodiment, the pre-flow difference threshold or the pre-set knock intensity threshold is obtained by querying a corresponding pre-set map according to an engine speed and an intake pressure.
In one possible embodiment, if the determined comparison indicates that the EGR actual flow is inaccurate, the method further includes:
an EGR data fault signal is sent to inform a user to service EGR system related components.
In a second aspect, the present application provides an EGR flow control device, the device comprising:
a flow difference determination module configured to determine a flow difference of the EGR actual flow and the EGR demand flow;
the data comparison module is configured to compare the flow difference value with a preset flow difference value threshold value and compare the current knock intensity of the engine with a preset knock intensity threshold value;
the correction module is configured to correct a fault diagnosis threshold value based on a threshold correction factor corresponding to the current knock intensity of the engine and correct a required EGR rate based on an EGR rate correction factor corresponding to the current knock intensity if the determined comparison result indicates that the EGR actual flow is inaccurate; the fault diagnosis threshold is used for determining a fault level based on the flow difference value; the demanded EGR rate is used to control the amount of exhaust gas entering the cylinders via EGR.
In one possible embodiment, before determining the flow difference between the actual EGR flow and the required EGR flow, the method further includes:
the safety working condition determining module is configured to determine that the vehicle meets the safety working condition;
wherein the safe operating conditions include all of the following:
the engine speed is greater than or equal to a preset speed threshold;
the intake pressure is greater than or equal to a preset pressure threshold;
the engine control system is free of EGR system faults and knock faults;
the gas composition adaptive factor is in a preset range.
In one possible implementation manner, if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold value and the current knock intensity is greater than or equal to a preset first knock intensity threshold value, the EGR actual flow is characterized as inaccurate;
and if the comparison result shows that the flow difference is smaller than or equal to a preset second flow difference threshold value and the current knock intensity is smaller than or equal to a preset second knock intensity threshold value, the actual flow of the EGR is not accurate.
In one possible implementation manner, if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold, and the current knock intensity is greater than or equal to a preset first knock intensity threshold;
performing the correction of the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity, the correction module configured to:
obtaining a threshold value increase factor for increasing a fault detection threshold value according to the corresponding relation between the knock intensity and the threshold value increase factor, and obtaining a corrected fault detection threshold value based on the threshold value increase factor; the threshold correction factor includes a threshold increase factor;
executing the correction of the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity, the correction module configured to:
according to the corresponding relation between the knocking intensity and the EGR rate increasing factor, an EGR rate increasing factor for increasing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate increasing factor; the EGR rate correction factor includes an EGR rate increase factor.
In one possible implementation manner, if the comparison result is that the flow difference is less than or equal to a preset second flow difference threshold value, and the current knock intensity is less than or equal to a preset second knock intensity threshold value;
performing the correction of the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity, the correction module configured to:
according to the corresponding relation between the knock intensity and the threshold reduction factor, obtaining a threshold reduction factor for reducing the fault detection threshold, and obtaining a corrected fault detection threshold based on the threshold reduction factor; the threshold correction factor includes a threshold reduction factor;
executing the correction of the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity, the correction module configured to:
according to the corresponding relation between the knocking intensity and the EGR rate reduction factor, an EGR rate reduction factor for reducing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate reduction factor; the EGR rate correction factor includes an EGR rate reduction factor.
In one possible embodiment, the pre-flow difference threshold or the pre-set knock intensity threshold is obtained by querying a corresponding pre-set map according to an engine speed and an intake pressure.
In one possible embodiment, if the determined comparison indicates that the EGR actual flow is inaccurate, the apparatus further includes:
and the fault signal sending module is configured to send an EGR data fault signal to inform a user of overhauling related parts of the EGR system.
In a third aspect, the present application provides an electronic device, comprising:
a processor and a memory;
the memory is configured to store the processor-executable instructions;
the processor is configured to execute the instructions to implement the EGR flow control method of any of the first aspects above.
In a fourth aspect, the present application provides a computer readable storage medium, which when executed by an electronic device, causes the electronic device to perform the EGR flow control method according to any of the first aspects described above.
In a fifth aspect, the present application provides a computer program product comprising a computer program:
the computer program, when executed by a processor, implements the EGR flow control method according to any one of the first aspect described above.
The technical scheme provided by the embodiment of the application at least brings the following beneficial effects:
in the embodiment of the application, after detecting that the difference exists between the actual flow of the EGR and the required flow of the EGR, the threshold value correction factor corresponding to the current knocking intensity is used for correcting the fault diagnosis threshold value, so that the accuracy of fault diagnosis under the working condition is improved, and fault false alarm is prevented; the required EGR rate is corrected by the EGR rate correction factor corresponding to the current knocking intensity, so that the problem that the engine performance and reliability are reduced due to inaccurate control of an EGR system caused by inaccurate EGR flow is solved, the accurate control of the EGR flow is realized, and the emission of NOx is reduced.
Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, and it is obvious that the drawings that are described below are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is an overall flow schematic diagram of an EGR flow control method provided in an embodiment of the present application;
fig. 2 is a schematic structural diagram of an EGR flow control device 200 according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Wherein the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
Also, in the description of the embodiments of the present application, "/" means or, unless otherwise indicated, for example, a/B may represent a or B; the text "and/or" is merely an association relation describing the associated object, and indicates that three relations may exist, for example, a and/or B may indicate: the three cases where a exists alone, a and B exist together, and B exists alone, and in addition, in the description of the embodiments of the present application, "plural" means two or more than two.
The terms "first," "second," and the like, are used below for descriptive purposes only and are not to be construed as implying or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", or the like may explicitly or implicitly include one or more such feature, and in the description of embodiments of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.
The following explains the related terms or devices to which embodiments of the present application relate:
ECU (Electronic Control Unit ).
EGR: an exhaust gas recirculation (Exhaust Gas Recirculation) separates a portion of the exhaust gases after combustion and directs them to the intake side for entry into the cylinders for combustion.
EGR rate: the ratio of the amount of exhaust gas entering the cylinder via EGR to the total amount of intake air drawn into the cylinder.
MAP: a map is input X, Y, and a corresponding numerical value Z is output; x is the engine speed, Y is the intake pressure, Z is the flow difference threshold or knock intensity threshold.
CURVE: inputting a value X into the one-dimensional array to obtain a corresponding output Y in the one-dimensional array; x is knock intensity, Y is threshold correction factor or EGR rate correction factor.
Knock intensity: the knocking degree of a certain cylinder of the engine under a certain working condition is generally represented by the ratio of the integrated voltage of a knocking signal to the voltage of a reference background noise signal, and the greater the value, the greater the knocking intensity.
In the related art, whether an EGR flow deviation fault exists is generally determined by comparing a difference value between an EGR actual flow calculated by an ECU and a required flow with a preset fault diagnosis threshold.
In the actual use process, the problems of aging of an EGR valve, poor production consistency of the EGR valve, signal drift or other abnormality of related sensors (such as an upstream pressure sensor, a downstream pressure sensor and a position feedback sensor) of an EGR system and the like exist, at the moment, the actual flow of the EGR calculated by the ECU can be distorted, and the difference between the actual flow of the EGR and the required flow of the EGR is inaccurate, so that the result of flow deviation faults is inaccurate, and meanwhile, the inaccuracy of the actual flow of the EGR also affects the normal control of the EGR system of the engine, thereby affecting the performance and reliability of the engine.
In view of this, the present application provides a method, an apparatus and a device for controlling EGR flow, so as to solve the problem that in the related art, the difference between the actual EGR flow and the required EGR flow is inaccurate, resulting in inaccurate results of flow deviation faults and affecting the control of the engine on the EGR system.
The inventive concepts of the present application can be summarized as follows: after determining the difference value between the actual flow of the EGR and the required flow of the EGR, judging the authenticity of the current flow difference value through the knock intensity, and if the actual flow of the EGR is determined to be inaccurate, correcting a fault diagnosis threshold value through a threshold value correction factor corresponding to the current knock intensity, so that the accuracy of fault diagnosis under the working condition is improved, and fault false alarm is prevented; the required EGR rate is corrected by the EGR rate correction factor corresponding to the current knocking intensity, so that the problem that the engine performance and reliability are reduced due to inaccurate control of an EGR system caused by inaccurate EGR flow is solved, the accurate control of the EGR flow is realized, and the emission of NOx is reduced.
After the main inventive concept of the embodiments of the present application is introduced, some simple descriptions are made below on application scenarios applicable to the technical solutions of the embodiments of the present application, and it should be noted that the application scenarios described below are only used to illustrate the embodiments of the present application and are not limiting. In specific implementation, the technical scheme provided by the embodiment of the application can be flexibly applied according to actual needs.
In order to facilitate understanding of the power generation control method of the range extender provided in the embodiment of the present application, the following is further described with reference to the accompanying drawings.
In one possible embodiment, the application provides an EGR flow control method, the overall flow of which is shown in fig. 1, including the following:
in step 101, a flow difference between the actual EGR flow and the demanded EGR flow is determined.
In step 102, the flow difference is compared to a preset flow difference threshold and the current knock intensity of the engine is compared to a preset knock intensity threshold.
In step 103, if the determined comparison result indicates that the EGR actual flow is inaccurate, the fault diagnosis threshold is corrected based on the threshold correction factor corresponding to the current knock intensity of the engine, and the required EGR rate is corrected based on the EGR rate correction factor corresponding to the current knock intensity.
The fault diagnosis threshold is used for determining a fault level based on the flow difference, different flow differences correspond to different deviation fault levels, for example, the flow difference is A, the corresponding deviation fault level is a first level, the flow difference is 2A, and the corresponding deviation fault level is a second level, so that the actual flow of the EGR is inaccurate, and the actual flow is originally the first level of the fault level and may be misjudged as the second level.
The demanded EGR rate is used to control the amount of exhaust gas entering the cylinders via EGR. The EGR rate has a larger influence on the in-cylinder combustion temperature, and as the EGR rate increases, the transient highest temperature and the average temperature in the cylinder are reduced, and as the high-temperature environment is a necessary condition for generating NOX, the increase of the EGR rate is beneficial to reducing the emission of NOX, and the required EGR rate is increased, so that more exhaust gas is recycled, and the actual flow of the EGR approaches the required flow of the EGR.
In one possible embodiment, the engine burns worse, is under-powered, and has no knock phenomenon if the actual flow of EGR is higher than the required flow of EGR, whereas the engine may have knock phenomenon when the actual flow of EGR is lower than the required flow of EGR.
When the flow difference is determined to be greater than or equal to a preset first flow difference threshold (the threshold is a positive value, and represents that the actual flow of the engine EGR calculated by the ECU is greater than the EGR required flow), the knock intensity is greater at the moment, but the current knock intensity is greater than or equal to a preset second knock intensity threshold, which indicates that the actual flow of the EGR calculated by the ECU is inaccurate and is greater than the actual flow of the EGR, and the failure level determined by the system is greater than the actual failure level.
In one possible implementation manner, for the above case, when the comparison result is that the flow difference is greater than or equal to the preset first flow difference threshold and the current knock intensity is greater than or equal to the preset first knock intensity threshold, in step 103, the fault diagnosis threshold is corrected based on the threshold correction factor corresponding to the current knock intensity, which may be implemented as follows:
according to the corresponding relation between the knock intensity and the threshold value increasing factor, the threshold value increasing factor for increasing the fault detection threshold value is obtained, and the fault detection threshold value after correction is obtained based on the threshold value increasing factor.
For example, the corresponding relation between the knock intensity and the threshold value increase factor is included in the CURVE1, the current knock intensity X1 is input, the corresponding threshold value increase factor Y1 is obtained, for example, Y1 is 1.1, and the corrected fault detection threshold value is 1.1 times of the original fault detection threshold value.
In step 103, the correction of the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity may be implemented as:
according to the corresponding relation between the knocking intensity and the EGR rate increasing factor, the EGR rate increasing factor for increasing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate increasing factor.
For example, the corresponding relation between the knock intensity and the EGR rate increase factor is included in the CURVE2, and the current knock intensity X2 is input to obtain the corresponding EGR rate increase factor Y2, for example, Y2 is 1.2, and the corrected required EGR rate is 1.2 times the original required EGR rate.
According to the embodiment of the application, the determined fault level accords with the actual situation by increasing the fault diagnosis threshold value; meanwhile, because the EGR actual flow is larger than the EGR required flow, the embodiment of the application further achieves recirculation through increasing the required EGR rate, and the EGR actual flow is close to the EGR required flow.
The threshold correction factor includes a threshold increase factor and a threshold decrease factor; the EGR rate correction factor includes an EGR rate increase factor and an EGR rate decrease factor.
In another possible implementation, when the flow difference is determined to be less than or equal to a preset second flow difference threshold (the threshold is a negative value, which indicates that the actual EGR flow of the engine calculated by the ECU is less than the EGR required flow), the knock intensity should be small or no knock exists, but the current knock intensity is less than or equal to a preset first knock intensity threshold, which indicates that the actual EGR flow calculated by the ECU is inaccurate and smaller than the actual EGR flow, resulting in a failure level determined by the system that is greater than the actual failure level.
In a possible implementation manner, for the case 2, when the comparison result is that the flow difference is less than or equal to the preset second flow difference threshold and the current knock intensity is less than or equal to the preset second knock intensity threshold, in step 103, the fault diagnosis threshold is corrected based on the threshold correction factor corresponding to the current knock intensity, which may be implemented as follows:
according to the corresponding relation between the knock intensity and the threshold reduction factor, the threshold reduction factor for reducing the fault detection threshold is obtained, and the corrected fault detection threshold is obtained based on the threshold reduction factor.
For example, the corresponding relation between the knock intensity and the threshold reduction factor is included in the CURVE3, the current knock intensity X3 is input, the corresponding threshold reduction factor Y3 is obtained, for example, Y3 is 0.9, and the corrected fault detection threshold is 90% of the original fault detection threshold.
In step 103, the correction of the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity may be implemented as:
according to the corresponding relation between the knocking intensity and the EGR rate reduction factor, the EGR rate reduction factor for reducing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate reduction factor.
For example, the corresponding relation between the knock intensity and the EGR rate reduction factor is included in the CURVE4, and the current knock intensity X4 is input to obtain the corresponding EGR rate reduction factor Y4, for example, Y4 is 0.8, and the corrected required EGR rate is 80% of the original required EGR rate.
According to the embodiment of the application, the determined fault level accords with the actual condition by reducing the fault diagnosis threshold value; meanwhile, because the EGR actual flow is smaller than the EGR required flow, the embodiment of the application further achieves recirculation of fewer exhaust gases by reducing the required EGR rate, and the EGR actual flow is close to the EGR required flow.
In another possible implementation manner, if the comparison result is that the flow difference is smaller than the preset first flow difference threshold and the flow difference is larger than the preset second flow difference threshold, the EGR actual flow is accurately represented;
or if the comparison result is that the flow difference value is larger than or equal to a preset first flow difference value threshold value and the current knock intensity is smaller than the preset first knock intensity threshold value, the EGR actual flow is represented accurately;
or if the comparison result is that the flow difference value is smaller than or equal to the preset second flow difference value threshold value and the current knock intensity is larger than the preset second knock intensity threshold value, the EGR actual flow is represented accurately.
In one possible implementation, before determining the flow difference between the actual EGR flow and the desired EGR flow, the embodiments of the present application will also determine that the vehicle meets safe operating conditions; wherein, safe operating conditions include all of the following:
the engine speed is greater than or equal to a preset speed threshold, such as 1200rpm;
the intake pressure is greater than or equal to a preset pressure threshold, such as 1.5bar, which is indicative of the load of the engine;
the engine control system is free of EGR system faults and knock faults, such as EGR valve, EGR position sensor, EGR upstream and downstream pressure sensor, and knock sensor related faults;
the gas composition self-adaptive factor is in a preset range, for example, the gas composition self-learning factor is between 0.9 and 1.1 in the preset range. The main standard of the gas component self-learning factor is that the gas component of the natural gas used by the current vehicle is in a normal range, namely the octane number and the heat value are in the normal range, abnormal knocking of the engine caused by the gas component can be avoided, and the accuracy of fault diagnosis and correction can be improved by adding the safe working condition.
In one possible embodiment, the pre-flow difference threshold or the pre-set knock intensity threshold is obtained by querying a corresponding pre-set map according to an engine speed and an intake pressure. For example, the preset first flow difference threshold is obtained by checking a corresponding preset MAP1 of the engine speed and the intake air pressure, that is, the engine speed X and the intake air pressure Y are input into the MAP1, and the output value Z is the preset first flow difference threshold.
In one possible implementation, if the determined comparison indicates that the actual EGR flow is inaccurate, the embodiments of the present application will also send out an EGR data fault signal to inform the user to overhaul the EGR system related components.
In summary, after determining the difference between the actual flow of the EGR and the required flow of the EGR, the embodiment of the present application determines the authenticity of the current flow difference through the knock intensity, and if it is determined that the actual flow of the EGR is inaccurate, corrects the fault diagnosis threshold through the threshold correction factor corresponding to the current knock intensity, so as to improve the accuracy of fault diagnosis under the working condition and prevent fault false alarm; the required EGR rate is corrected by the EGR rate correction factor corresponding to the current knocking intensity, so that the problem that the engine performance and reliability are reduced due to inaccurate control of an EGR system caused by inaccurate EGR flow is solved, the accurate control of the EGR flow is realized, and the emission of NOx is reduced.
Based on the same inventive concept, the present application provides an EGR flow control device, as shown in fig. 2, the device 200 includes:
a flow difference determination module 201 configured to determine a flow difference between the EGR actual flow and the EGR demand flow;
a data comparison module 202 configured to compare the flow difference to a preset flow difference threshold and to compare a current knock intensity of the engine to a preset knock intensity threshold;
the correction module 203 is configured to correct a fault diagnosis threshold based on a threshold correction factor corresponding to the current knock intensity of the engine and correct a required EGR rate based on an EGR rate correction factor corresponding to the current knock intensity if the determined comparison result indicates that the EGR actual flow is inaccurate; the fault diagnosis threshold is used for determining a fault level based on the flow difference value; the demanded EGR rate is used to control the amount of exhaust gas entering the cylinders via EGR.
In one possible embodiment, before determining the flow difference between the actual EGR flow and the required EGR flow, the method further includes:
the safety working condition determining module is configured to determine that the vehicle meets the safety working condition;
wherein the safe operating conditions include all of the following:
the engine speed is greater than or equal to a preset speed threshold;
the intake pressure is greater than or equal to a preset pressure threshold;
the engine control system is free of EGR system faults and knock faults;
the gas composition adaptive factor is in a preset range.
In one possible implementation manner, if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold value and the current knock intensity is greater than or equal to a preset first knock intensity threshold value, the EGR actual flow is characterized as inaccurate;
and if the comparison result shows that the flow difference is smaller than or equal to a preset second flow difference threshold value and the current knock intensity is smaller than or equal to a preset second knock intensity threshold value, the actual flow of the EGR is not accurate.
In one possible implementation manner, if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold, and the current knock intensity is greater than or equal to a preset first knock intensity threshold;
performing the correction of the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity, the correction module configured to:
obtaining a threshold value increase factor for increasing a fault detection threshold value according to the corresponding relation between the knock intensity and the threshold value increase factor, and obtaining a corrected fault detection threshold value based on the threshold value increase factor; the threshold correction factor includes a threshold increase factor;
executing the correction of the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity, the correction module configured to:
according to the corresponding relation between the knocking intensity and the EGR rate increasing factor, an EGR rate increasing factor for increasing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate increasing factor; the EGR rate correction factor includes an EGR rate increase factor.
In one possible implementation manner, if the comparison result is that the flow difference is less than or equal to a preset second flow difference threshold value, and the current knock intensity is less than or equal to a preset second knock intensity threshold value;
performing the correction of the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity, the correction module configured to:
according to the corresponding relation between the knock intensity and the threshold reduction factor, obtaining a threshold reduction factor for reducing the fault detection threshold, and obtaining a corrected fault detection threshold based on the threshold reduction factor; the threshold correction factor includes a threshold reduction factor;
executing the correction of the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity, the correction module configured to:
according to the corresponding relation between the knocking intensity and the EGR rate reduction factor, an EGR rate reduction factor for reducing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate reduction factor; the EGR rate correction factor includes an EGR rate reduction factor.
In one possible embodiment, the pre-flow difference threshold or the pre-set knock intensity threshold is obtained by querying a corresponding pre-set map according to an engine speed and an intake pressure.
In one possible embodiment, if the determined comparison indicates that the EGR actual flow is inaccurate, the apparatus further includes:
and the fault signal sending module is configured to send an EGR data fault signal to inform a user of overhauling related parts of the EGR system.
An electronic device 130 according to this embodiment of the present application is described below with reference to fig. 3. The electronic device 130 shown in fig. 3 is only an example and should not be construed as limiting the functionality and scope of use of embodiments of the present application.
As shown in fig. 3, the electronic device 130 is in the form of a general-purpose electronic device. Components of electronic device 130 may include, but are not limited to: the at least one processor 131, the at least one memory 132, and a bus 133 connecting the various system components, including the memory 132 and the processor 131.
Bus 133 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a processor, and a local bus using any of a variety of bus architectures.
Memory 132 may include readable media in the form of volatile memory such as Random Access Memory (RAM) 1321 and/or cache memory 1322, and may further include Read Only Memory (ROM) 1323.
Memory 132 may also include a program/utility 1325 having a set (at least one) of program modules 1324, such program modules 1324 include, but are not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment.
The electronic device 130 may also communicate with one or more external devices 134 (e.g., keyboard, pointing device, etc.), one or more devices that enable a user to interact with the electronic device 130, and/or any device (e.g., router, modem, etc.) that enables the electronic device 130 to communicate with one or more other electronic devices. Such communication may occur through an input/output (I/O) interface 135. Also, electronic device 130 may communicate with one or more networks such as a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network, such as the Internet, through network adapter 136. As shown, network adapter 136 communicates with other modules for electronic device 130 over bus 133. It should be appreciated that although not shown, other hardware and/or software modules may be used in connection with electronic device 130, including, but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, data backup storage systems, and the like.
In an exemplary embodiment, the present application also provides a computer readable storage medium including instructions, such as memory 132 including instructions, executable by processor 131 of electronic device 130 to perform the EGR flow control method described above. Alternatively, the computer readable storage medium may be a non-transitory computer readable storage medium, for example, a ROM, a Random Access Memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.
In an exemplary embodiment, a computer program product is also provided, comprising a computer program which, when executed by the processor 131, implements an EGR flow control method as provided herein.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.
Claims (10)
1. An EGR flow control method, characterized by comprising:
determining a flow difference between the EGR actual flow and the EGR demand flow;
comparing the flow difference with a preset flow difference threshold, and comparing the current knock intensity of the engine with a preset knock intensity threshold;
if the determined comparison result indicates that the EGR actual flow is inaccurate, correcting a fault diagnosis threshold value based on a threshold value correction factor corresponding to the current knock intensity of the engine, and correcting a required EGR rate based on an EGR rate correction factor corresponding to the current knock intensity; the fault diagnosis threshold is used for determining a fault level based on the flow difference value; the demanded EGR rate is used to control the amount of exhaust gas entering the cylinders via EGR.
2. The method of claim 1, wherein prior to determining the flow difference between the actual EGR flow and the desired EGR flow, further comprising:
determining that the vehicle meets the safe working condition;
wherein the safe operating conditions include all of the following:
the engine speed is greater than or equal to a preset speed threshold;
the intake pressure is greater than or equal to a preset pressure threshold;
the engine control system is free of EGR system faults and knock faults;
the gas composition adaptive factor is in a preset range.
3. The method of claim 1, wherein if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold and the current knock intensity is greater than or equal to a preset first knock intensity threshold, then characterizing that EGR actual flow is inaccurate;
and if the comparison result shows that the flow difference is smaller than or equal to a preset second flow difference threshold value and the current knock intensity is smaller than or equal to a preset second knock intensity threshold value, the actual flow of the EGR is not accurate.
4. The method according to claim 3, wherein if the comparison result is that the flow difference is greater than or equal to a preset first flow difference threshold, and the current knock intensity is greater than or equal to a preset first knock intensity threshold;
the correcting the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity comprises the following steps:
obtaining a threshold value increase factor for increasing a fault detection threshold value according to the corresponding relation between the knock intensity and the threshold value increase factor, and obtaining a corrected fault detection threshold value based on the threshold value increase factor; the threshold correction factor includes a threshold increase factor;
the correcting the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity includes:
according to the corresponding relation between the knocking intensity and the EGR rate increasing factor, an EGR rate increasing factor for increasing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate increasing factor; the EGR rate correction factor includes an EGR rate increase factor.
5. The method according to claim 3, wherein if the comparison result is that the flow difference is less than or equal to a preset second flow difference threshold, and the current knock intensity is less than or equal to a preset second knock intensity threshold;
the correcting the fault diagnosis threshold based on the threshold correction factor corresponding to the current knock intensity comprises the following steps:
according to the corresponding relation between the knock intensity and the threshold reduction factor, obtaining a threshold reduction factor for reducing the fault detection threshold, and obtaining a corrected fault detection threshold based on the threshold reduction factor; the threshold correction factor includes a threshold reduction factor;
the correcting the required EGR rate based on the EGR rate correction factor corresponding to the current knock intensity includes:
according to the corresponding relation between the knocking intensity and the EGR rate reduction factor, an EGR rate reduction factor for reducing the required EGR rate is obtained, and the corrected required EGR rate is obtained based on the EGR rate reduction factor; the EGR rate correction factor includes an EGR rate reduction factor.
6. The method of claim 1, wherein the pre-flow difference threshold or the pre-set knock intensity threshold is derived from an engine speed and an intake pressure query corresponding pre-set map.
7. The method of any one of claims 1-6, further comprising, if the determined comparison indicates that the EGR actual flow is inaccurate:
an EGR data fault signal is sent to inform a user to service EGR system related components.
8. An EGR flow control device, characterized in that the device comprises:
a flow difference determination module configured to determine a flow difference of the EGR actual flow and the EGR demand flow;
the data comparison module is configured to compare the flow difference value with a preset flow difference value threshold value and compare the current knock intensity of the engine with a preset knock intensity threshold value;
the correction module is configured to correct a fault diagnosis threshold value based on a threshold correction factor corresponding to the current knock intensity of the engine and correct a required EGR rate based on an EGR rate correction factor corresponding to the current knock intensity if the determined comparison result indicates that the EGR actual flow is inaccurate; the fault diagnosis threshold is used for determining a fault level based on the flow difference value; the demanded EGR rate is used to control the amount of exhaust gas entering the cylinders via EGR.
9. An electronic device, comprising:
a processor and a memory;
the memory is configured to store the processor-executable instructions;
the processor is configured to execute the instructions to implement the EGR flow control method of any of claims 1-7.
10. A computer readable storage medium, characterized in that instructions in the computer readable storage medium, when executed by a processor of an electronic device, enable the electronic device to perform the EGR flow control method according to any of claims 1-7.
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