CN114687841B - System and method for estimating accumulated carbon quantity of passenger car particle catcher - Google Patents
System and method for estimating accumulated carbon quantity of passenger car particle catcher Download PDFInfo
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- CN114687841B CN114687841B CN202210247875.6A CN202210247875A CN114687841B CN 114687841 B CN114687841 B CN 114687841B CN 202210247875 A CN202210247875 A CN 202210247875A CN 114687841 B CN114687841 B CN 114687841B
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 183
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 183
- 239000002245 particle Substances 0.000 title claims abstract description 139
- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000004364 calculation method Methods 0.000 claims abstract description 30
- 238000012544 monitoring process Methods 0.000 claims abstract description 27
- 238000009825 accumulation Methods 0.000 claims abstract description 19
- 238000000638 solvent extraction Methods 0.000 claims abstract description 13
- 238000010586 diagram Methods 0.000 claims description 44
- 230000001186 cumulative effect Effects 0.000 claims description 41
- 230000007774 longterm Effects 0.000 abstract description 3
- 238000005192 partition Methods 0.000 description 8
- 239000000243 solution Substances 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000013618 particulate matter Substances 0.000 description 4
- 230000008929 regeneration Effects 0.000 description 4
- 238000011069 regeneration method Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000012887 quadratic function Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/022—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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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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- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- General Physics & Mathematics (AREA)
- Processes For Solid Components From Exhaust (AREA)
Abstract
The invention discloses a system and a method for estimating accumulated carbon quantity of a passenger car particle catcher, wherein the system comprises a pressure difference monitoring module, a carbon accumulation characteristic module and a carbon accumulation quantity calculating module; the pressure difference monitoring module is used for monitoring the pressure difference between the front and the rear of exhaust entering the gasoline engine particle catcher; the carbon accumulating characteristic module is used for determining the current carbon accumulating characteristic of the gasoline engine particle catcher according to the pressure difference before and after exhaust entering the gasoline engine particle catcher and the volume flow of vehicle exhaust; the accumulated carbon quantity calculation module is used for calculating the current accumulated carbon quantity of the gasoline engine particle catcher according to the current accumulated carbon characteristic of the gasoline engine particle catcher. The system designed by the invention comprehensively estimates the accumulated carbon quantity of the gasoline engine particle catcher in a partitioning way based on the front-rear exhaust pressure difference and the vehicle exhaust volume flow of the gasoline engine particle catcher. The system-based estimation method avoids the accumulated errors of other generation rate algorithms in long-term operation, and can accurately and stably estimate the current accumulated carbon quantity of the gasoline engine particle catcher.
Description
Technical Field
The invention relates to the technical field of engine control systems, in particular to a system and a method for estimating accumulated carbon quantity of a passenger car particle catcher.
Background
In order to obtain better performance, modern automobile engines adopt new technologies such as direct injection in a cylinder, a high-pressure common rail, exhaust gas circulation, valve timing and the like, but with the introduction of the direct injection technology in the cylinder, the level of particulate matter emission is increased. In the face of strict regulations on particulate matters and the number of the particulate matters in the regulations, each manufacturer needs to take corresponding emission reduction measures. The addition of GPF (Gasoline PARTICLE FILTER, gasoline engine particulate trap) to the exhaust system is the current mainstream solution. In the development design of GPF, the following problems are faced: in case of an overload of the GPF, where a large amount of combustible particulate matter is accumulated in the GPF, a regeneration reaction occurs which is too severe to run away, and burns the GPF out of control, which is an unacceptable safety risk for spontaneous combustion of the vehicle. Therefore, a set of monitoring strategies needs to be designed to monitor the loading amount of combustible particulate matters in the GPF, and then the behavior of the engine is correspondingly regulated, so that the service life of the GPF is prolonged. The current GPF monitoring scheme in the industry is mainly a particle accumulation model method, which is used for establishing a particle accumulation model by researching the generation and consumption rates of particles. The advantage of this solution is that no additional equipment is required for monitoring, the disadvantage being that the errors in the model are constantly accumulated, since it is essentially an accumulated model. If thorough regeneration (i.e., deterministic depletion of all particulate matter) is not performed for a long period of time, errors may accumulate to an unacceptable level, which may adversely affect the service life of the GPF.
Disclosure of Invention
The invention aims to solve the defects of the background technology and provides a system and a method for estimating the accumulated carbon quantity of a gasoline engine particle catcher based on differential pressure sensor signals and in different areas and avoiding overlarge accumulated error caused by a traditional accumulated model.
To achieve the purpose, the system for estimating the accumulated carbon quantity of the passenger car particle catcher, which is designed by the invention, is characterized in that: the device comprises a differential pressure monitoring module, a carbon accumulating characteristic module and a carbon accumulating amount calculating module;
the pressure difference monitoring module is used for monitoring the pressure difference between the front and the rear of exhaust entering the gasoline engine particle catcher;
The carbon accumulating characteristic module is used for determining the current carbon accumulating characteristic of the gasoline engine particle catcher according to the pressure difference before and after exhaust entering the gasoline engine particle catcher and the volume flow of vehicle exhaust;
the accumulated carbon quantity calculation module is used for calculating the current accumulated carbon quantity of the gasoline engine particle catcher according to the current accumulated carbon characteristic of the gasoline engine particle catcher.
Further, the system for estimating the carbon accumulation amount of the passenger car particle catcher further comprises an exhaust volume flow monitoring module, wherein the exhaust volume flow monitoring module is used for equivalent of the intake volume flow calculated by the engine internal model to the vehicle exhaust volume flow.
Further, the carbon accumulating characteristic module comprises an image drawing module, a characteristic partitioning module and a characteristic matching module;
The image drawing module is used for drawing a differential pressure flow characteristic diagram;
The characteristic partitioning module is used for partitioning the differential pressure flow characteristic diagram according to the curve characteristic of the differential pressure flow characteristic diagram;
The characteristic matching module is used for matching the current accumulated carbon quantity of the gasoline engine particle catcher into a corresponding area of the differential pressure flow characteristic diagram according to the pressure difference before and after the exhaust entering the gasoline engine particle catcher and the vehicle exhaust volume flow.
Further, the pressure difference flow characteristic diagram is a relation diagram of the vehicle exhaust volume flow and the pressure difference before and after the exhaust of the gasoline engine particle catcher.
Further, the characteristic partitioning module divides the differential pressure flow characteristic map into a low flow area, a linear area and a high flow area according to the magnitude of the vehicle exhaust volume flow.
Further, the characteristic matching module matches the accumulated carbon quantity of the current gasoline engine particle catcher to a low flow zone or a linear zone or a high flow zone according to the pressure difference before and after the exhaust gas enters the gasoline engine particle catcher and the volume flow of the vehicle exhaust gas.
Further, the accumulated carbon quantity calculating module comprises a low flow area calculating module, a linear area calculating module and a high flow area calculating module;
The low flow area calculation module is used for calculating the accumulated carbon quantity of the gasoline engine particle catcher positioned in the low flow area;
The linear region calculation module is used for calculating the accumulated carbon quantity of the gasoline engine particle catcher positioned in the linear region;
the high flow area calculation module is used for calculating the accumulated carbon quantity of the gasoline engine particle catcher positioned in the high flow area.
Further, the accumulated carbon amount calculating method of the low flow area is as follows: and establishing a speed model of the particulate matters generated by the engine under different working conditions, and obtaining the accumulated carbon quantity S of the current gasoline engine particulate catcher by an integral method. Regarding the method for calculating the cumulative carbon value through the rate model, reference may be made to "those matters of state six solutions" issued by the united electronic public number-particle catcher OBD monitoring solution ", patent No. CN112101415A, entitled" cumulative carbon prediction method, apparatus, automobile, cloud server and computer-readable storage medium ", and patent No. CN210714813U, entitled" external gasoline engine exhaust particulate matter filtration system for gasoline vehicle refitting ".
The accumulated carbon amount calculation method of the linear region is as follows: the image drawing module draws a differential pressure flow characteristic diagram in a linear region under the current accumulated carbon quantity, calculates the slope K of the differential pressure flow characteristic diagram in the linear region, determines the ratio n of the accumulated carbon quantity S of the gasoline engine particle catcher in the linear region to the slope K, and calculates the product of Kn to obtain the accumulated carbon quantity S of the current gasoline engine particle catcher.
The calculation method of the high flow area calculation module comprises the following steps: establishing a rate model of particulate matters generated by the engine under different working conditions, obtaining the accumulated carbon quantity S of the current gasoline engine particle catcher by an integral method (the method for calculating the accumulated carbon quantity by the rate model is the same as the accumulated carbon quantity calculation method of a low flow area), comparing the accumulated carbon quantity S with a primary load accumulation threshold S1 of the gasoline engine particle catcher and a serious load accumulation threshold S2 of the gasoline engine particle catcher, if S is less than or equal to S1, the accumulated carbon quantity of the current gasoline engine particle catcher is S1, if S1 is less than S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S, and if S is more than or equal to S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S2.
Further, the method for determining the ratio n of the cumulative carbon quantity to the slope of the gasoline engine particle catcher in the linear region is as follows: the image drawing module draws a differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ', calculates the slope K ' of the differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ' in a linear region, and calculates the ratio n of the S ' to the K '.
Specifically, the method for estimating the accumulated carbon quantity of the passenger car particle catcher comprises the following steps: it comprises the following steps:
Step one: monitoring the pressure difference before and after exhaust entering the gasoline engine particle catcher and the volume flow of vehicle exhaust, and drawing a pressure difference flow characteristic diagram;
step two: dividing regions of a differential pressure flow characteristic diagram of the gasoline engine particle catcher under the current accumulated carbon quantity according to the accumulated carbon characteristic, and determining accumulated carbon quantity calculating methods of different regions;
step three: judging the region of the differential pressure flow characteristic diagram of the accumulated carbon quantity of the current gasoline engine particle catcher, and calculating the accumulated carbon quantity of the current gasoline engine particle catcher by a accumulated carbon quantity calculating method of the region.
The beneficial effects of the invention are as follows: the system designed by the invention comprehensively estimates the accumulated carbon quantity of the gasoline engine particle catcher in a partitioning way based on the front-rear exhaust pressure difference and the vehicle exhaust volume flow of the gasoline engine particle catcher. The system-based estimation method avoids the accumulated errors of other generation rate algorithms in long-term operation, also greatly eliminates the estimation influence of the loading distribution characteristic of the gasoline engine particle catcher on the accumulated carbon quantity through partition calculation, and can accurately and stably estimate the current accumulated carbon quantity of the gasoline engine particle catcher. The system designed by the invention has no requirement on the arrangement of the gasoline engine particle catcher, so the system is suitable for all passenger vehicles provided with the gasoline engine particle catcher, is a universal system and an estimation method, and can be widely popularized.
Drawings
FIG. 1 is a diagram showing the connection of a system module for estimating the cumulative carbon content of a passenger car particle catcher in the present invention;
FIG. 2 is a graph of engine exhaust volumetric flow versus GPF front-to-back differential pressure for calibrating GPF cumulative carbon values in accordance with the present invention;
FIG. 3 is a logic block diagram of the cumulative carbon amount calculation in the low flow area of the present invention;
FIG. 4 is a block diagram of the cumulative carbon calculation for the linear region of the present invention;
FIG. 5 is a logic block diagram of the cumulative amount of carbon in the high flow area of the present invention;
The system comprises a 1-differential pressure monitoring module, a 2-exhaust volume flow monitoring module, a 3-image drawing module, a 4-characteristic partition module, a 5-characteristic matching module, a 6-low flow area calculating module, a 7-linear area calculating module and an 8-high flow area calculating module.
Detailed Description
The invention will now be described in further detail with reference to the drawings and to specific examples.
The system for estimating the accumulated carbon quantity of the passenger car particle catcher as shown in fig. 1 comprises a differential pressure monitoring module 1, an exhaust volume flow monitoring module 2, an accumulated carbon characteristic module and an accumulated carbon quantity calculating module.
The differential pressure monitoring module 1 comprises a differential pressure sensor arranged on the gasoline engine particle catcher, and the differential pressure sensor is used for monitoring the pressure difference of exhaust entering the gasoline engine particle catcher before and after; the exhaust gas volumetric flow monitoring module 2 is configured to equate the intake volumetric flow calculated by the engine internal model to the vehicle exhaust gas volumetric flow.
The carbon accumulating characteristic module comprises an image drawing module 3, a characteristic partitioning module 4 and a characteristic matching module 5. The image drawing module 3 is used for drawing a pressure difference flow characteristic diagram, namely a relation diagram of vehicle exhaust volume flow and the pressure difference before and after exhaust of the gasoline engine particle catcher. The characteristic partitioning module 4 is configured to partition the differential pressure flow characteristic map into regions according to a curve characteristic of the differential pressure flow characteristic map: dividing a differential pressure flow characteristic diagram into a low flow area, a linear area and a high flow area according to the volume flow of the vehicle exhaust; the range of the volume flow Q1 of the vehicle exhaust in the low flow area is Q0 to or less than Q1 to less than Q2; the range of the vehicle exhaust volume flow Q3 in the linear region is Q2-Q3-Q4; the vehicle exhaust volume flow Q5 in the high flow region ranges from Q5 > Q4. The characteristic matching module 5 is used for matching the current accumulated carbon quantity of the gasoline engine particle catcher to a low flow area or a linear area or a high flow area of the differential pressure flow characteristic diagram according to the pressure difference before and after the exhaust entering the gasoline engine particle catcher and the vehicle exhaust volume flow.
The accumulated carbon amount calculation module includes a low flow rate region calculation module 6, a linear region calculation module 7, and a high flow rate region calculation module 8. The low flow area calculating module 6 is used for calculating the accumulated carbon amount of the gasoline engine particle catcher positioned in the low flow area, and the method is as follows: and establishing a speed model of the particulate matters generated by the engine under different working conditions, and obtaining the accumulated carbon quantity S of the current gasoline engine particulate catcher by an integral method. The linear region calculation module 7 is used for calculating the accumulated carbon quantity of the gasoline engine particle catcher positioned in the linear region, and the method is as follows: the image drawing module 3 draws a differential pressure flow characteristic diagram in a linear region under the current accumulated carbon quantity, calculates the slope K of the differential pressure flow characteristic diagram in the linear region, determines the ratio n of the accumulated carbon quantity S of the gasoline engine particle catcher in the linear region to the slope K, and calculates the product of Kn to obtain the accumulated carbon quantity S of the current gasoline engine particle catcher; the method for determining the ratio n of the accumulated carbon quantity to the slope of the gasoline engine particle catcher in the linear region is as follows: the image drawing module 3 draws a differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ', calculates the slope K ' of the differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ' in a linear region, and calculates the ratio n of the S ' to the K '. The high flow area calculating module 8 is used for calculating the accumulated carbon amount of the gasoline engine particle catcher positioned in the high flow area, and the method is as follows: establishing a speed model of generating particulate matters by the engine under different working conditions, obtaining the accumulated carbon quantity S of the current gasoline engine particle catcher by an integral method, comparing the accumulated carbon quantity S with a primary load accumulation threshold S1 of the gasoline engine particle catcher and a serious load accumulation threshold S2 of the gasoline engine particle catcher, wherein if S is less than or equal to S1, the accumulated carbon quantity of the current gasoline engine particle catcher is S1, if S1 is less than S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S, and if S is more than or equal to S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S2.
The method of the system for estimating the cumulative carbon content of the passenger car particle catcher designed by the invention is further described below: as shown in fig. 2-5, the present invention uses the partition to establish three different algorithms to accurately estimate the current cumulative carbon content of the gasoline engine particulate trap.
As shown in fig. 2, on the premise of changing the cumulative carbon amount of the known gasoline engine particle catcher, the exhaust volume flow rate and the pressure difference between the front and the rear of the GPF are changed correspondingly, so that seven (i.e., S1 'to S7', or more than two) relationship curves of the exhaust volume flow rate and the pressure difference between the front and the rear of the GPF can be drawn through the image drawing module 3, and according to the seven relationship curves of the exhaust volume flow rate and the pressure difference between the front and the rear of the GPF, a low, medium and high partition can be established to independently design the cumulative carbon amount calculation strategy. The vehicle exhaust volume flow rate Q1 in the low flow region is 0.03m3/s or more (i.e., Q0 described above) and less than 0.05m3/s (i.e., Q2 described above). The vehicle exhaust volume flow rate Q3 in the linear region is 0.05m3/s or more and 0.15m3/s or less (i.e., Q4 described above). The vehicle exhaust volume flow Q5 in the high flow region is greater than 0.15m3/s.
The principle of partition establishment is as follows: the relative error of the GPF differential pressure measurement is too large in the curve in the low flow area and cannot depend on any differential pressure signal, so that a speed model of the engine for generating particulate matters under different working conditions needs to be established in the area, and then the accumulated quantity is obtained in an integral mode.
The curve in the linear region can be approximately regarded as a diagonal line, and the linear region can be found to have the following characteristics through calculation: taking S2 'as an example, wherein the cumulative carbon amount of S2' is 0.5g, the slope of S2 'in the linear region is K2, the ratio of the cumulative carbon amount of S2' to the slope of the linear region is 0.5/K2, and the ratio is assumed to be n2; similarly, the ratio of the cumulative carbon amount of S3 'to the slope of the linear region is 1/K3, the ratio of the cumulative carbon amount of S4' to the slope of the linear region is n3, the ratio of the cumulative carbon amount of S4 'to the slope of the linear region is 2/K4, the ratio of the cumulative carbon amount of S5' to the slope of the linear region is 3/K5, the ratio of the cumulative carbon amount of S6 'to the slope of the linear region is 5/K6, the ratio of the cumulative carbon amount of S6 to the slope of the linear region is 10/K7, and the ratio of the cumulative carbon amount of S7' to the slope of the linear region is n7. Calculated n2=n3=n4=n5=n6=n7=n. Therefore, the cumulative carbon value of the current GPF can be obtained by calculating Kn as long as the slope K of the current GPF in the linear region is determined. The actual accumulated carbon quantity of the linear region can be obtained by drawing a relationship curve of the exhaust volume flow of the GPF with known accumulated carbon quantity and the pressure difference before and after the GPF, and then multiplying n by the slope K to obtain the accumulated carbon quantity.
The curve in the high flow area has obvious non-characteristic of pressure difference, and the relative error of GPF pressure difference measurement is too large to depend on any pressure difference signal, so that a speed model of the particulate matters generated by the engine under different working conditions needs to be established in the area, and then the accumulated quantity is obtained in an integral mode.
The accumulated carbon amount of each zone is specifically described below: and monitoring the exhaust volume flow and the pressure difference between the front and the rear of the GPF, comparing the three areas with the three areas in FIG. 2, determining the area where the current GPF accumulated carbon quantity is located, and then calculating the accumulated carbon quantity according to the current area.
Low flow area: when the exhaust volume flow and the pressure difference before and after the GPF are monitored to be in a low flow area, the relative error of the pressure difference measurement is too large to depend on any pressure difference signal, so that a speed model of the engine for generating particulate matters under different working conditions needs to be established in the area, and then the accumulated quantity is obtained in an integral mode. The model of the accumulation rate can be calculated from both the time and the mileage dimensions. The particle generation rate is determined by the atmospheric pressure, the intake air temperature, the coolant temperature, and the downtime. The accumulation model continues to accumulate on the basis of existing measurements during engine operation.
Linear region: the following characteristics can be summarized from fig. 2: 1. for a particular flow rate, a higher cumulative amount of carbon in the gasoline engine particulate trap will create a greater pressure differential. 2. For a gasoline engine particle catcher under a specific accumulated carbon quantity, the front-rear pressure difference of the gasoline engine particle catcher is increased along with the rising of the volume flow of vehicle exhaust. And the increasing trend is progressively faster (i.e., the curve is convex downward). 3. For each point on the same curve, the cumulative carbon content of the corresponding gasoline engine particle catcher is the same. Therefore, theoretically, the cumulative carbon amount of the gasoline engine particle catcher can be known only by knowing the vehicle exhaust volume flow at a certain moment and then based on the front-rear exhaust pressure difference of the gasoline engine particle catcher measured at that moment.
For example, under the conditions of the current vehicle exhaust volume flow and the front-rear exhaust pressure difference of the gasoline engine particle catcher, the accumulated carbon quantity is between 1 and 2g, and a specific value cannot be obtained. To solve this problem, a new regression algorithm is introduced. Specifically, when the exhaust volume flow and the pressure difference between the front and the rear of the GPF are monitored to be located in a linear region, an image drawing module 3 collects 800 points according to the monitored values of the exhaust volume flow and the pressure difference between the front and the rear of the GPF, draws a pressure difference flow characteristic diagram located in the linear region under the current accumulated carbon quantity, calculates the slope K of the pressure difference flow characteristic diagram located in the linear region, determines the ratio n of the accumulated carbon quantity S of the gasoline engine particle catcher located in the linear region to the slope K, and calculates the product of the Kn to obtain the accumulated carbon quantity S of the current gasoline engine particle catcher; the method for determining the ratio n of the accumulated carbon quantity to the slope of the gasoline engine particle catcher in the linear region is as follows: the image drawing module 3 draws a differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ', calculates the slope K ' of the differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ' in a linear region, and calculates the ratio n of the S ' to the K '.
The regression algorithm was designed based on the results of one of the following observations: each curve is very close to a conic, or some interval in the middle (linear region) can be considered as a straight line. The cumulative carbon quantity in each linear region corresponds to the coefficient of a quadratic curve or the slope of a straight line. And the coefficient or slope is a value for each point that can be calculated by interpolation. For example, consider that the differential pressure flow chart of the current cumulative carbon amount is a straight line in the linear region, the slope of the differential pressure flow chart of the known cumulative carbon amount of 1g in the linear region is 1, the slope of the differential pressure flow chart of the cumulative carbon amount of 2g in the linear region is 2, the ratio of the cumulative carbon amount S to the slope K at this time is 1, and if the slope of the differential pressure flow chart of the current cumulative carbon amount measured at this time in the linear region is 1.6, the corresponding cumulative carbon amount at this time is 1.6x1, i.e. 1.6g. Thus, the cumulative carbon value under any state can be obtained under the condition of carrying out limited experiments.
The curve of the linear region is actually closer to a quadratic curve, and for the convenience of calculating the slope of this segment, the curve of the linear region is approximately regarded as a straight line. It is therefore necessary to establish a correction to remove the effect of the quadratic term. The slope of the fitted straight line is calculated by measuring a large number of data points (more than 800) and then by means of regression, and the latest accumulated carbon quantity of the gasoline engine particle catcher is updated according to the slope.
Differential pressure signal processing: let the differential pressure be dP and the volumetric flow be Qvol. If the relationship between them is considered to satisfy the quadratic power function relationship, then:
dP＝a*Qvol2+b*Qvol+c (1)
a. b and c are constants.
By calibrating a proper a, the method leads to ：
dPmodified＝dP-a*Qvol2＝b*Qvol+c (2)
Fitting the quadratic function into a straight line, and calculating the slope of the straight line through a regression algorithm.
The regression algorithm:
Obtaining a fitting straight line
The current slope value is calculated according to the regression algorithm formula.Is a slope,/>Is a constant, x is the exhaust volume flow, y is the GPF front-to-back pressure difference, x i is the collected exhaust volume flow, y i is the collected GPF front-to-back pressure difference value,/>For the average value of all exhaust gas volume flows collected,/>Is the average of all GPF front-to-back differential pressures collected.
The slope calculation may be performed in the ECU by accumulating the present value on the basis of the previous value.
High flow area: when the exhaust volume flow and the pressure difference before and after the GPF are monitored to be in a high flow area, the non-characteristics of the pressure difference are obvious, and a regression algorithm cannot be used for calculating specific values. The critical threshold point design is generally made according to design requirements. In this area, only two key points are defined: s1 represents a primary load accumulation threshold value, and S2 represents a serious load accumulation threshold value. (these two data are intrinsic values of the gasoline engine particle catcher and do not need to be measured). When the accumulated carbon quantity S is less than or equal to S1, the running of the vehicle is not affected; above S1 but below S2, the vehicle needs to begin actively attempting to enter a regeneration condition; when the vehicle is higher than or equal to S2, the vehicle needs to give an alarm to prompt the driver to repair, and the vehicle is prevented from entering a regeneration working condition. The high flow area cannot give a certain particle mass, so that a speed model of the particle mass produced by the engine under different working conditions needs to be established, the accumulated carbon quantity S of the current gasoline engine particle catcher is obtained through an integral method, the accumulated carbon quantity S is compared with a primary load accumulation threshold S1 of the gasoline engine particle catcher and a serious load accumulation threshold S2 of the gasoline engine particle catcher, if S is less than or equal to S1, the accumulated carbon quantity of the current gasoline engine particle catcher is S1, if S1 is less than S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S, and if S is more than or equal to S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S2.
Partition coordination: for the regional coordination of the estimation of the accumulated carbon quantity of the particle traps of the three gasoline engines, the following principles are satisfied: 1. the estimated value of the low flow area is always accumulated according to the calibrated speed; 2. the regression algorithm (linear region) yields the most reliable data, and thus once a measurement is made with the regression algorithm, this data is used to determine the cumulative carbon content of the current gasoline engine particulate trap. 3. The current accumulated carbon quantity is monitored by the high flow area, so that the accumulated carbon quantity is ensured not to exceed a serious load accumulation threshold S2, and the running safety of the vehicle is ensured.
The system designed by the invention comprehensively estimates the accumulated carbon quantity of the gasoline engine particle catcher in a partitioning way based on the front-rear exhaust pressure difference and the vehicle exhaust volume flow of the gasoline engine particle catcher. The system-based estimation method avoids the accumulated errors of other generation rate algorithms in long-term operation, also greatly eliminates the estimation influence of the loading distribution characteristic of the gasoline engine particle catcher on the accumulated carbon quantity through partition calculation, and can accurately and stably estimate the current accumulated carbon quantity of the gasoline engine particle catcher. The system designed by the invention has no requirement on the arrangement of the gasoline engine particle catcher, so the system is suitable for all passenger vehicles provided with the gasoline engine particle catcher, is a universal system and an estimation method, and can be widely popularized.
The above description is only of the preferred embodiment of the present invention, and is not intended to limit the structure of the present invention in any way. Any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (8)
1. A system for estimating the cumulative carbon content of a passenger vehicle particle catcher, comprising: the device comprises a differential pressure monitoring module (1), a carbon accumulating characteristic module and a carbon accumulating amount calculating module;
the pressure difference monitoring module (1) is used for monitoring the pressure difference between the front and the rear of exhaust entering the gasoline engine particle catcher;
The carbon accumulating characteristic module is used for determining the current carbon accumulating characteristic of the gasoline engine particle catcher according to the pressure difference before and after exhaust entering the gasoline engine particle catcher and the volume flow of vehicle exhaust;
The accumulated carbon quantity calculation module is used for calculating the current accumulated carbon quantity of the gasoline engine particle catcher according to the current accumulated carbon characteristic of the gasoline engine particle catcher;
The system for estimating the carbon accumulation amount of the passenger car particle catcher further comprises an exhaust volume flow monitoring module (2), wherein the exhaust volume flow monitoring module (2) is used for equivalently converting the air intake volume flow calculated by an engine internal model into the vehicle exhaust volume flow;
the carbon accumulating characteristic module comprises an image drawing module (3), a characteristic partitioning module (4) and a characteristic matching module (5);
the image drawing module (3) is used for drawing a differential pressure flow characteristic diagram;
the characteristic partitioning module (4) is used for partitioning the differential pressure flow characteristic diagram according to the curve characteristic of the differential pressure flow characteristic diagram;
the characteristic matching module (5) is used for matching the current accumulated carbon quantity of the gasoline engine particle catcher into a corresponding area of a pressure difference flow characteristic diagram according to the pressure difference before and after exhaust entering the gasoline engine particle catcher and the vehicle exhaust volume flow;
The accumulated carbon quantity calculation module is used for adopting different accumulated carbon quantity calculation methods for different areas of the differential pressure flow characteristic diagram.
2. The system for estimating a cumulative carbon amount of a particulate trap of a passenger vehicle of claim 1, wherein: the pressure difference flow characteristic diagram is a relation diagram of vehicle exhaust volume flow and the pressure difference before and after exhaust of the gasoline engine particle catcher.
3. The system for estimating a cumulative carbon amount of a particulate trap of a passenger vehicle of claim 2, wherein: the characteristic partitioning module (4) divides the differential pressure flow characteristic diagram into a low flow area, a linear area and a high flow area according to the size of the vehicle exhaust volume flow.
4. A system for estimating a cumulative carbon amount of a particulate trap of a passenger vehicle as set forth in claim 3, wherein: the characteristic matching module (5) matches the accumulated carbon quantity of the current gasoline engine particle catcher to a low flow area or a linear area or a high flow area according to the pressure difference before and after the exhaust entering the gasoline engine particle catcher and the vehicle exhaust volume flow.
5. The system for estimating a cumulative carbon amount of a particulate trap of a passenger vehicle of claim 4, wherein: the accumulated carbon quantity calculating module comprises a low flow area calculating module (6), a linear area calculating module (7) and a high flow area calculating module (8);
the low flow area calculation module (6) is used for calculating the accumulated carbon quantity of the gasoline engine particle catcher positioned in the low flow area;
The linear region calculation module (7) is used for calculating the accumulated carbon quantity of the gasoline engine particle catcher positioned in the linear region;
The high flow area calculation module (8) is used for calculating the accumulated carbon quantity of the gasoline engine particle catcher positioned in the high flow area.
6. The system for estimating a cumulative carbon amount of a particulate trap of a passenger vehicle of claim 5, wherein: the accumulated carbon quantity calculating method of the low flow area comprises the following steps: establishing a speed model of generating particulate matters by the engine under different working conditions, and obtaining the accumulated carbon quantity S of the current gasoline engine particulate catcher by an integral method;
The accumulated carbon amount calculation method of the linear region is as follows: the image drawing module (3) draws a differential pressure flow characteristic diagram positioned in a linear region under the current accumulated carbon quantity, calculates the slope K of the differential pressure flow characteristic diagram positioned in the linear region, determines the ratio n of the accumulated carbon quantity S of the gasoline engine particle catcher positioned in the linear region to the slope K, and calculates the product of the Kn to obtain the accumulated carbon quantity S of the current gasoline engine particle catcher;
The calculation method of the high flow area calculation module comprises the following steps: establishing a speed model of generating particulate matters by the engine under different working conditions, obtaining the accumulated carbon quantity S of the current gasoline engine particle catcher by an integral method, comparing the accumulated carbon quantity S with a primary load accumulation threshold S1 of the gasoline engine particle catcher and a serious load accumulation threshold S2 of the gasoline engine particle catcher, wherein if S is less than or equal to S1, the accumulated carbon quantity of the current gasoline engine particle catcher is S1, if S1 is less than S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S, and if S is more than or equal to S2, the accumulated carbon quantity of the current gasoline engine particle catcher is S2.
7. The system for estimating a cumulative carbon amount of a particulate trap of a passenger vehicle of claim 6, wherein: the method for determining the ratio n of the accumulated carbon quantity to the slope of the gasoline engine particle catcher in the linear region is as follows: the image drawing module (3) draws a differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ', calculates the slope K ' of the differential pressure flow characteristic diagram of the gasoline engine particle catcher with the known accumulated carbon quantity S ' in a linear region, and calculates the ratio n of the S ' to the K '.
8. A method of estimating a passenger vehicle particle trap carbon deposit based on the system of estimating a passenger vehicle particle trap carbon deposit as defined in any one of claims 1-7, characterized by: it comprises the following steps:
Step one: monitoring the pressure difference before and after exhaust entering the gasoline engine particle catcher and the volume flow of vehicle exhaust, and drawing a pressure difference flow characteristic diagram;
step two: dividing regions of a differential pressure flow characteristic diagram of the gasoline engine particle catcher under the current accumulated carbon quantity according to the accumulated carbon characteristic, and determining accumulated carbon quantity calculating methods of different regions;
step three: judging the region of the differential pressure flow characteristic diagram of the accumulated carbon quantity of the current gasoline engine particle catcher, and calculating the accumulated carbon quantity of the current gasoline engine particle catcher by a accumulated carbon quantity calculating method of the region.
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| CN100491704C (en) * | 2004-08-10 | 2009-05-27 | 日产自动车株式会社 | Estimation device and method of particulate matter deposit amount in diesel particulate filter |
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| CN104863679A (en) * | 2015-03-31 | 2015-08-26 | 凯龙高科技股份有限公司 | DPF system carbon loading capacity estimation and blocking state judgment method |
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