CN108278146B - Particulate filter control system for internal combustion engine - Google Patents
Particulate filter control system for internal combustion engine Download PDFInfo
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- CN108278146B CN108278146B CN201810081972.6A CN201810081972A CN108278146B CN 108278146 B CN108278146 B CN 108278146B CN 201810081972 A CN201810081972 A CN 201810081972A CN 108278146 B CN108278146 B CN 108278146B
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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
- F01N9/00—Electrical control of exhaust gas treating apparatus
- F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
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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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
- F01N2900/1402—Exhaust gas composition
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
- F01N2900/1611—Particle filter ash amount
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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 invention provides a control system of a particulate filter of an internal combustion engine, which comprises a particulate flow module, an oxygen flow module, a nitrogen dioxide flow module, an active regeneration module, a passive regeneration module, a trapping rate module and a particulate accumulation module, wherein the particulate accumulation module is connected with the oxygen flow module; the particle flow module is used for calculating the particle flow entering the particle filter; the oxygen flow module is used for calculating the oxygen flow entering the particulate filter; the nitrogen dioxide flow module is used for calculating the nitrogen dioxide flow entering the particulate filter; the active regeneration module is used for calculating the active regeneration reaction rate of the particulate filter; the passive regeneration module is used for calculating the passive regeneration reaction rate of the particulate filter; a trapping rate module that determines a rate of particulate accumulation within the particulate filter based on the particulate flow rate and the regeneration reaction rate; the particulate accumulation module determines an amount of particulate accumulation within the particulate filter based on the particulate accumulation rate integral. The invention enables accurate calculation of the particulate load in a particulate filter of an internal combustion engine without relying on pressure or differential pressure sensors.
Description
Technical Field
The invention relates to the field of internal combustion engines, in particular to an energy-saving and emission-reducing system of a diesel engine.
Background
Scheme 1: chinese patent CN1304743C provides an engine exhaust cleaning component, the control method of which includes a method of estimating the carbon loading of the particulate filter. The technical means and the achieved effect that this patent adopted are: the engine control unit estimates a particulate accumulation amount of the particulate filter based on a difference between the upstream pressure and the downstream pressure of the particulate filter, and proposes to adjust the estimated particulate accumulation amount using an exhaust flow rate obtained from an engine speed and a load through a lookup table. The patent is deficient and the reason is that the influence of the particle distribution state on the pressure difference estimation is not taken into consideration when only the pressure difference is used as a method of estimating the accumulation amount of the particulate matter. After the particulate filter is not completely regenerated, the particulate distribution state is a non-uniform distribution state, the corresponding relation between the pressure difference and the cumulant is not the same as that in uniform distribution, if the distribution state is not considered to be corrected, an estimation error of the particulate cumulant can be generated, the regeneration time of the particulate filter is influenced to be correctly calculated, and the risk of thermal runaway during the regeneration of the particulate filter is caused.
Scheme 2: chinese patent CN1297733C provides an engine exhaust purification device, the control method of which includes a method for estimating the carbon load of the particulate filter. The technical means and the achieved effect that this patent adopted are: detecting a pressure difference upstream and downstream of the particulate filter using two sensor detection pressure sensors, and obtaining a first inferred cumulative amount from MAP lookup at engine speed; a second inferred cumulative amount indicating the cumulative amount after the end of the previous forced regeneration is obtained by looking up MAP using the engine speed and the fuel injection amount. When either of these two inferred cumulative amounts exceeds the corresponding threshold is the primary condition for triggering forced regeneration, the system then determines whether to initiate forced regeneration based on conditions such as oxidation catalyst temperature. The patent is deficient and the reason is that the influence of the particle distribution on the pressure difference is not considered in calculating the first inferred cumulative amount; in calculating the second estimated cumulative amount, only the engine speed and the fuel injection amount are used as conditions for calculating particulate emissions, but the influence of the EGR rate (exhaust gas recirculation rate) and the engine cooling water temperature on the particulate emissions in the actual operation of the internal combustion engine is not taken into consideration.
Scheme 3: chinese patent CN 100538033C provides a control method of an exhaust gas purification system and an exhaust gas purification system. The technical means and the achieved effect that this patent adopted are: the regeneration of the particulate filter is determined by two factors of the differential pressure and the mileage, and the timing of forced regeneration of the continuous regeneration type particulate filter is determined by comparing the particulate accumulation amount and the mileage with a predetermined determination value. The method takes into account the problem of oil dilution caused by particulate filter regeneration. And comprehensively judging whether manual or automatic particle filter regeneration is triggered under the current condition according to the particle accumulation amount and the driving mileage obtained by the pressure difference, and reminding a driver to go to a maintenance center for maintenance under the condition that the engine oil is too diluted and still needs regeneration. The defects and reasons of the patent are as follows: in the calculation of the particulate accumulation amount using the differential pressure as a parameter, the influence of the particulate distribution state on the calculation of the particulate accumulation amount by the differential pressure is not considered, and the actual particulate accumulation amount may be caused to be higher than the estimated amount, causing thermal runaway of the particulate filter regeneration.
The following disadvantages mainly exist in the prior art:
1. after the particulate filter is not completely regenerated, the particulate distribution state is a non-uniform distribution state, the corresponding relation of the pressure difference and the cumulant is not the same as that in uniform distribution, if the distribution state is not considered to be corrected, the estimation error of the particulate cumulant can be generated, the regeneration time of the particulate filter is influenced to be correctly calculated, and the risk of thermal runaway during the regeneration of the particulate filter is caused;
2. when the engine speed and the fuel injection amount are used as conditions for calculating particulate emissions, the influence of the engine cooling water temperature on the particulate emissions of the internal combustion engine in actual operation thereof is not taken into consideration. (ii) a
3. The second method of calculating the particulate accumulation amount when the differential pressure sensor fails or the second method has a small correction amount and limited accuracy, and cannot provide an accurate regeneration timing for the particulate filter.
Disclosure of Invention
It is an object of the present invention to overcome the deficiencies of the prior art and to provide a control system for a particulate filter of an internal combustion engine that accurately calculates the particulate load on the particulate filter of the internal combustion engine without relying on pressure or differential pressure sensors. The technical scheme adopted by the invention is as follows:
a control system of a particulate filter of an internal combustion engine comprises a particulate flow module, an oxygen flow module, a nitrogen dioxide flow module, an active regeneration module, a passive regeneration module, a trapping rate module and a particulate accumulation module;
the particle flow module is used for calculating the particle flow entering the particle filter;
the oxygen flow module is used for calculating and obtaining the oxygen flow at the outlet of the oxidation catalyst, namely the oxygen flow entering the particulate filter;
the nitrogen dioxide flow module is used for calculating the nitrogen dioxide flow at the outlet of the oxidation catalyst, namely the nitrogen dioxide flow entering the particulate filter;
the active regeneration module is used for calculating the reaction rate of particles and oxygen in the particulate filter during the active regeneration of the particulate filter, namely the active regeneration reaction rate of the particulate filter;
the passive regeneration module is used for calculating the reaction rate of particles in the particle filter and nitrogen dioxide during the passive regeneration of the particle filter, namely the passive regeneration reaction rate of the particle filter;
a trapping rate module that determines a rate of particulate accumulation within the particulate filter based on the particulate flow rate and the regeneration reaction rate;
the particulate accumulation module determines an amount of particulate accumulation within the particulate filter based on the particulate accumulation rate integral.
The control system can accurately calculate the particulate load in a particulate filter of an internal combustion engine without relying on a pressure or differential pressure sensor.
The particle flow module is used for calculating the particle flow entering the particle filter; the particle flow is jointly determined by the basic particle flow under the steady-state working condition and the correction quantity under the transient working condition; determining the basic particle flow under the steady-state working condition by inquiring a corresponding MAP table through a basic particle calculation module according to the working conditions of the internal combustion engine represented by the variable of the rotating speed and the fuel injection quantity of the internal combustion engine; meanwhile, the correction of the basic particle flow under the steady-state working condition by considering the cooling water temperature of the internal combustion engine and the like; a water temperature correction module queries a corresponding MAP table according to the cooling water temperature of the internal combustion engine to obtain a water temperature correction coefficient, a transient working condition correction module calculates and obtains a transient air-fuel ratio deviation according to the rotating speed of the internal combustion engine, the fuel injection quantity and the air inflow of the internal combustion engine, and the value queries the corresponding MAP table to obtain a transient working condition correction coefficient; the particle flow correction calculation module corrects the basic particle flow under the steady-state working condition calculated by the basic particle calculation module through the water temperature correction coefficient calculated by the water temperature correction module and the transient working condition correction coefficient calculated by the transient working condition correction module to obtain the particle flow entering the particle filter;
the oxidation catalyst outlet oxygen flow module is used for calculating the oxygen flow of oxygen in the exhaust gas discharged from the outlet of the exhaust manifold after the oxygen in the exhaust gas is reacted by the oxidation catalyst and enters the particulate filter; the device comprises an exhaust manifold outlet oxygen content coefficient calculation module and a DOC outlet oxygen flow calculation module; oxygen flow at the outlet of an exhaust manifold of the internal combustion engine is determined by internal combustion engine combustion control parameters such as transient air-fuel ratio, exhaust gas recirculation rate and the like of the internal combustion engine through an exhaust manifold outlet oxygen content coefficient calculation module, and an oxygen content coefficient in the exhaust gas is obtained by inquiring a corresponding MAP table or is obtained by calculation according to a combustion model; in the DOC outlet oxygen flow calculation module, the mass flow of the exhaust gas at the outlet of the exhaust manifold is multiplied by the oxygen content coefficient at the outlet of the exhaust manifold obtained by the exhaust manifold outlet oxygen content coefficient calculation module to obtain the oxygen flow entering the oxidation catalyst; inquiring corresponding MAP (MAP) according to the oxygen flow entering the oxidation catalyst and the temperature of the oxidation catalyst carrier or calculating the reaction rate of the obtained oxygen in the oxidation catalyst according to a chemical reaction model of the oxidation catalyst; checking the corresponding MAP according to the reaction rate of the oxygen in the catalyst and the post-injection oil quantity to obtain the oxygen quantity consumed by the oxidation catalyst in the reaction per unit time; the oxygen flow entering the oxidation catalyst subtracts the oxygen consumed by the oxidation catalyst in unit time to obtain the oxygen flow at the outlet of the oxidation catalyst, namely the oxygen flow entering the particulate filter.
The nitrogen dioxide flow module multiplies the flow of nitrogen oxide at the exhaust manifold of the internal combustion engine by the conversion rate of the nitrogen oxide in the oxidation catalyst to nitrogen dioxide to obtain the flow of the nitrogen dioxide entering the particulate filter; basic flow of nitrogen oxides at the exhaust manifold of the internal combustion engine is determined by inquiring a corresponding MAP table according to the working conditions of the internal combustion engine represented by variables such as the rotating speed of the internal combustion engine, the fuel injection quantity and the like, and the basic flow of the nitrogen oxides is corrected by considering the exhaust gas recirculation rate and the cooling water temperature of the internal combustion engine at the same time to obtain the flow of the nitrogen oxides at the exhaust manifold of the internal combustion engine; the basic conversion rate of the conversion from the nitrogen oxide to the nitrogen dioxide in the oxidation catalyst is determined by inquiring a corresponding MAP table or a chemical reaction model according to the temperature of the oxidation catalyst and the flow of the nitrogen oxide at an exhaust manifold, and the conversion rate from the nitrogen oxide to the nitrogen dioxide in the oxidation catalyst is obtained after the aging degree coefficient of the oxidation catalyst is corrected; nitrogen oxide with known flow (nitrogen oxide flow at an exhaust manifold) discharged by the internal combustion engine enters an oxidation catalyst, and the nitrogen dioxide flow at the outlet of the oxidation catalyst, namely the nitrogen dioxide flow entering a particulate filter, can be obtained according to the determined conversion rate;
the oxidation catalyst age factor is determined by querying the corresponding MAP table for the cumulative time that the oxidation catalyst substrate temperature exceeds the age temperature threshold.
The active regeneration module is used for calculating the active reaction efficiency of the particles and the oxygen in the particle filter during the active regeneration of the particle filter by multiplying the basic reaction efficiency of the oxygen and the particles in the particle filter by an active reaction efficiency correction coefficient; the basic reaction efficiency of oxygen and particles in the particle filter is obtained by checking a corresponding MAP or a reaction model according to the reaction conditions in the particle filter represented by the temperature of the carrier of the particle filter and the oxygen flow at the outlet of the oxidation catalyst; the active reaction efficiency correction coefficient is obtained by looking up a corresponding curve characteristic table according to the particle deposition characteristic reflected by the particle cumulant; the rate of reaction of the particulates with oxygen in the particulate filter during active regeneration of the particulate filter may be obtained by multiplying the accumulation of particulates in the particulate filter by the efficiency of the active reaction.
The passive regeneration module is used for calculating the reaction rate of particles in the filter and nitrogen dioxide during the passive regeneration of the particulate filter by multiplying the particle accumulation amount in the particulate filter and the passive reaction efficiency in the particulate filter; the passive reaction efficiency in the particulate filter is obtained by checking a corresponding MAP table or a passive reaction model according to the temperature of exhaust gas at the outlet of the oxidation catalyst, the flow rate of nitrogen dioxide entering the particulate filter and the cumulative amount of particulates in the particulate filter; the passive regeneration reaction rate of the particulate filter can be obtained by multiplying the passive reaction efficiency in the particulate filter by the accumulation amount of the particulate in the particulate filter.
The trapping rate module comprises a trapping efficiency calculation module and a trapping rate calculation module; in the trapping efficiency calculation module, the trapping efficiency of the particulate filter is obtained by checking a corresponding MAP table or a trapping efficiency model according to the filtering characteristics represented by the accumulated amount of the particulates in the particulate filter and the total volume of the particulate filter; the trapping rate calculation module multiplies the flow of the particles entering the particle filter by the trapping efficiency of the particle filter calculated by the trapping efficiency calculation module to obtain the trapping rate of the particle filter, namely the mass of the particles trapped in unit time; subtracting the active regeneration reaction rate of the particulate filter and the passive regeneration reaction rate of the particulate filter from the trapping rate of the particulate filter to obtain the particulate accumulation rate in the particulate filter;
the particle accumulation module comprises a particle integration module; the particle integration module is used for calculating the current particle accumulation amount in the particle filter; when the internal combustion engine is in an operating state, the particle integration module starts to use the particle accumulation integration initial value and the particle accumulation rate to carry out particle mass integration at the moment, and the particle accumulation amount accumulated in the particle filter is calculated; resetting the integral value when the controller sends out a signal for replacing or cleaning the particulate filter, wherein the reset initial value is a filter reset initial value; the controller saves the particulate accumulation amount calculated by the particulate integration module when the internal combustion engine is stopped, and as a particulate accumulation integration initial value for calculation at the next time the internal combustion engine is operated.
The invention has the advantages that:
1. the method can avoid the danger that the thermal runaway of the active regeneration of the particulate filter is caused due to the error caused by the uneven distribution of the particulates caused by the incomplete regeneration of the particulate filter when the particulate accumulation is calculated by using the pressure difference, and improve the safety of the system.
2. The risk that the particle cumulant cannot be calculated due to failure of the pressure sensor when the particle cumulant is calculated by using the pressure difference can be avoided, and the safety of the system is improved;
3. the calculation process does not depend on a differential pressure sensor, and the emission control system does not need to be provided with a pressure sensor, so that the cost is reduced; when the method is applied to an exhaust control system using a pressure sensor, the particle accumulation amount calculated by the pressure difference can be corrected by the calculation method in the invention, and the reliability and the precision of the system are improved;
4. when the particulate, nitrogen oxide and oxygen emission are calculated, relevant influence conditions are fully considered, and the emission amount of each emission can be accurately calculated.
Drawings
Fig. 1 is a schematic view of an exhaust gas treatment structure of an internal combustion engine of the present invention.
FIG. 2 is a schematic structural diagram of the present invention.
FIG. 3 is a schematic view of a particle flow module according to the present invention.
FIG. 4 is a schematic diagram of an oxygen flow module according to the present invention.
Figure 5 is a schematic view of a nitrogen dioxide flow module of the present invention.
FIG. 6 is a schematic diagram of the active regeneration module calculation according to the present invention.
FIG. 7 is a schematic diagram of a passive regeneration module according to the present invention.
FIG. 8 is a schematic of the capture rate module calculation of the present invention.
FIG. 9 is a schematic calculation diagram of the particle accumulation module of the present invention.
Detailed Description
The invention is further illustrated by the following specific figures and examples.
In fig. 1, exhaust gas from an internal combustion engine passes through an oxidation catalyst (DOC) through an exhaust manifold and then is treated by a particulate filter (DPF) to meet national exhaust emission standards.
FIG. 2 is a schematic diagram of a particulate filter control system for an internal combustion engine. The invention relates to a control system of a particulate filter of an internal combustion engine, which comprises a particulate flow module, an oxygen flow module, a nitrogen dioxide flow module, an active regeneration module, a passive regeneration module, a trapping rate module and a particulate accumulation module.
The particle flow module is used for calculating the particle discharge flow of the exhaust gas of the internal combustion engine before treatment;
the oxygen flow module calculates the oxygen flow of the exhaust gas of the internal combustion engine before the exhaust gas is not processed and the oxygen flow of the exhaust gas after the exhaust gas is reacted by the oxidation catalyst;
the nitrogen dioxide flow module calculates the discharge flow of nitrogen oxide before the exhaust gas of the internal combustion engine is not treated and the flow of nitrogen dioxide in the exhaust gas after the exhaust gas is reacted by the oxidation catalyst, namely the flow of the nitrogen dioxide entering the particulate filter;
the active regeneration module is used for calculating the reaction rate of particles and oxygen in the particulate filter during the active regeneration of the particulate filter, namely the active regeneration reaction rate of the particulate filter;
the passive regeneration module is used for calculating the reaction rate of particles in the particle filter and nitrogen dioxide during the passive regeneration of the particle filter, namely the passive regeneration reaction rate of the particle filter;
a trapping rate module that determines a rate of particulate accumulation within the particulate filter based on the particulate flow rate and the regeneration reaction rate;
the particulate accumulation module determines an amount of particulate accumulation within the particulate filter based on the particulate accumulation rate integral.
FIG. 3 is a schematic view of a particulate flow module; the particulate flow module is used to calculate the particulate flow 109 into the particulate filter; the particle flow is jointly determined by the basic particle flow under the steady-state working condition and the correction quantity under the transient working condition; according to the engine working conditions represented by variables such as the engine speed 102 and the fuel injection quantity 103, the corresponding MAP table is inquired through the basic particle calculation module 105 to determine the basic particle flow rate under the steady-state working conditions, and meanwhile, the correction of the basic particle flow rate under the steady-state working conditions needs to be considered, such as the engine cooling water temperature 101 and the engine air intake quantity 104; the particle flow correction calculation module 108 corrects the steady-state working condition basic particle flow calculated by the basic particle calculation module 106 through the water temperature correction coefficient calculated by the water temperature correction module 105 and the transient working condition correction coefficient calculated by the transient working condition correction module 107 to obtain the particle flow 109 entering the particle filter; the water temperature correction module 105 queries a corresponding MAP table according to the cooling water temperature 101 of the internal combustion engine to obtain a water temperature correction coefficient, the transient working condition correction module 107 calculates a transient air-fuel ratio deviation according to the rotating speed 102 of the internal combustion engine, the fuel injection quantity 103 and the air intake quantity 104 of the internal combustion engine, and queries the corresponding MAP table according to the value to obtain the transient working condition correction coefficient;
FIG. 4 is an oxidation catalyst outlet oxygen flow module for calculating an oxygen flow 208 into the particulate filter after oxygen in the exhaust gas exiting the exhaust manifold outlet has reacted through the oxidation catalyst; the device comprises an exhaust manifold outlet oxygen content coefficient calculation module 206 and a DOC outlet oxygen flow calculation module 207; the oxygen flow at the outlet of the exhaust manifold of the internal combustion engine is calculated according to the oxygen content coefficient in the exhaust gas obtained by inquiring a corresponding MAP table through an exhaust manifold outlet oxygen content coefficient calculating module 206 according to the combustion control parameters of the internal combustion engine such as the transient air-fuel ratio 201, the exhaust gas recirculation rate 203 and the like of the internal combustion engine or the oxygen content coefficient in the exhaust gas obtained by calculating according to a combustion model; in a DOC outlet oxygen flow calculation module 207, the exhaust manifold outlet exhaust gas mass flow 202 is multiplied by an exhaust manifold outlet oxygen content coefficient obtained by an exhaust manifold outlet oxygen content coefficient calculation module 206 to obtain the oxygen flow entering an oxidation catalyst; inquiring corresponding MAP (MAP) according to the oxygen flow entering the oxidation catalyst and the oxidation catalyst carrier temperature 204 or calculating the reaction rate of the oxygen in the oxidation catalyst according to a chemical reaction model of the oxidation catalyst; the reaction rate of oxygen in the catalyst and the post-injection amount 205 are used for checking the corresponding MAP to obtain the amount of oxygen consumed by the oxidation catalyst in the reaction per unit time; the oxygen flow entering the oxidation catalyst subtracts the oxygen consumed by the oxidation catalyst per unit time to obtain the oxidation catalyst outlet oxygen flow 208, i.e., the oxygen flow entering the particulate filter.
FIG. 5 is a schematic view of a particulate filter inlet nitrogen dioxide flow module. The particulate filter inlet nitrogen dioxide flow module is used to calculate the nitrogen dioxide flow into the particulate filter 311; there is no means for treating the exhaust gases between the exhaust manifold of the internal combustion engine and the oxidation catalyst, so the flow of nitrogen oxides at the outlet of the exhaust manifold of the internal combustion engine can be regarded as the flow of nitrogen oxides at the inlet of the oxidation catalyst. In the oxidation catalyst inlet nitrogen oxide calculation module 309, the basic flow of the oxidation catalyst inlet nitrogen oxide is determined by querying a corresponding MAP table according to the engine operating conditions represented by the variables such as the engine speed 102 and the engine fuel injection quantity 103, and meanwhile, the basic flow of the nitrogen oxide is corrected by considering the exhaust gas recirculation rate 203 and the engine cooling water temperature 101, so that the flow of the oxidation catalyst inlet nitrogen oxide (namely the flow of the nitrogen oxide at the exhaust manifold of the engine) is obtained. In the conversion rate calculation module 308 for converting nitrogen oxide into nitrogen dioxide in the oxidation catalyst, the basic conversion rate for converting nitrogen oxide into nitrogen dioxide in the oxidation catalyst is determined by checking a corresponding MAP file or a chemical reaction model according to the temperature 301 of the oxidation catalyst and the inlet exhaust gas flow 202 of the oxidation catalyst, and the conversion rate for converting nitrogen oxide into nitrogen dioxide in the oxidation catalyst is obtained after correcting a catalyst aging degree coefficient obtained by checking a corresponding MAP when the temperature 204 of the carrier of the oxidation catalyst exceeds an aging temperature threshold value. In the flow calculation module 310 for the NO2 at the outlet of the oxidation catalyst, the flow 311 of nitrogen dioxide at the outlet of the oxidation catalyst, i.e. the flow 311 of nitrogen dioxide entering the particulate filter, is obtained from the flow of nitrogen oxide at the inlet of the oxidation catalyst determined by the calculation module 309 according to the conversion determined by the calculation module 308.
FIG. 6 is a schematic diagram of the active regeneration module calculation. The active regeneration module 404 is configured to calculate a rate 405 of reaction of the particulate in the filter with oxygen during active regeneration in the particulate filter, which is indicative of a mass of the particulate consumed by the passive regeneration per unit time. In the active regeneration module 404, the basic efficiency of the reaction of oxygen with particulates in the particulate filter is obtained by examining the reaction conditions in the particulate filter as characterized by the particulate filter support temperature 401 and the oxidation catalyst outlet oxygen flow 208 for a corresponding MAP or reaction model; the active reaction efficiency correction coefficient is obtained by looking up a corresponding curve characteristic table from the particle deposition characteristics reflected by the particle accumulation amount 808. Multiplying the basic reaction efficiency of oxygen and particles in the particulate filter during active regeneration in the particulate filter by an active reaction efficiency correction factor to calculate the active reaction efficiency of the particles and oxygen in the particulate filter during active regeneration of the particulate filter; finally, the active regeneration reaction rate 405 of the particulate filter can be obtained by multiplying the accumulation amount of particulates in the particulate filter by the active reaction efficiency.
FIG. 7 is a schematic diagram of a passive regeneration module calculation. The passive regeneration module 504 is configured to calculate a rate 505 of reaction of particulates in the particulate filter with nitrogen dioxide during passive regeneration in the particulate filter, which is indicative of a mass of particulates consumed by the passive regeneration per unit time. Within the passive regeneration module 504, the passive reaction efficiency within the particulate filter is determined from a corresponding MAP or reaction model for the passive reaction conditions within the particulate filter as characterized by the oxidation catalyst outlet exhaust temperature 501 and the ratio of the oxidation catalyst outlet nitrogen dioxide flow 311 to the accumulated amount of particulates 808 within the particulate filter. The passive regeneration reaction rate 505 of the particulate filter can be obtained by multiplying the passive reaction efficiency in the particulate filter by the accumulation amount 808 of particulates in the particulate filter.
FIG. 8 is a schematic of the capture rate module calculation; it comprises a capture efficiency calculation module 706 and a capture rate calculation module 607; the trapping efficiency calculation module 706 is used to calculate the percentage of particles in the exhaust gas flowing through the particulate filter that are trapped in the carrier by the particulate filter to the total particles in the exhaust gas; in the trapping efficiency calculation module 706, the filtering characteristics represented by the accumulated amount 808 of the particulates in the particulate filter and the total volume 705 of the particulate filter are checked by a corresponding MAP table or a trapping efficiency model to obtain the trapping efficiency of the particulate filter; the trapping rate calculation module 607 multiplies the particulate filter trapping efficiency calculated by the trapping efficiency calculation module 706 by the particulate flow rate 109 entering the particulate filter to obtain the trapping rate of the particulate filter, that is, the mass of the particulates trapped in a unit time; the particulate filter trapping rate minus the particulate filter active regeneration reaction rate 405 and the particulate filter passive regeneration reaction rate 505 yields the particulate accumulation rate 608 within the particulate filter.
FIG. 9 is a schematic of particle accumulation module calculations; it includes a particle integration module 807; the particle integration module 807 is configured to calculate a current particle accumulation amount 808 in the particle filter; when the engine stop state 801 is not 0, that is, the engine is in an operating state, the particulate integration module 807 starts to perform particulate mass integration using the particulate accumulation integration initial value 804 and the particulate accumulation rate 608, and calculates a particulate accumulation amount 808 accumulated in the particulate filter; when the controller issues a particulate filter replacement or cleaning signal 802 (e.g., to a service station to replace or clean a particulate filter), the integral value is reset to an initial filter reset value 805; at the time of engine stop, the controller will save the particulate accumulation amount 808 calculated by the particulate integration module 807, and as a particulate accumulation integration initial value for calculation at the time of the next engine operation.
The present invention is independent of a differential pressure sensor and can calculate particulate accumulation independently or as a backup particulate accumulation for a particulate filtration system with a differential pressure sensor.
Claims (8)
1. A control system of a particulate filter of an internal combustion engine comprises a particulate flow module, an oxygen flow module, a nitrogen dioxide flow module, an active regeneration module, a passive regeneration module, a trapping rate module and a particulate accumulation module;
the particle flow module is used for calculating the particle flow entering the particle filter;
the oxygen flow module is used for calculating and obtaining the oxygen flow at the outlet of the oxidation catalyst, namely the oxygen flow entering the particulate filter;
the nitrogen dioxide flow module is used for calculating the nitrogen dioxide flow at the outlet of the oxidation catalyst, namely the nitrogen dioxide flow entering the particulate filter;
the active regeneration module is used for calculating the reaction rate of particles and oxygen in the particulate filter during the active regeneration of the particulate filter, namely the active regeneration reaction rate of the particulate filter;
the passive regeneration module is used for calculating the reaction rate of particles in the particle filter and nitrogen dioxide during the passive regeneration of the particle filter, namely the passive regeneration reaction rate of the particle filter;
a trapping rate module that determines a rate of particulate accumulation within the particulate filter based on the particulate flow rate and the regeneration reaction rate;
a particle accumulation module determines an amount of particle accumulation in the particle filter based on the particle accumulation rate integral;
the particle flow module is used for calculating the particle flow entering the particle filter; the particle flow is jointly determined by the basic particle flow under the steady-state working condition and the correction quantity under the transient working condition; determining the basic particle flow under the steady-state working condition by inquiring a corresponding MAP table through a basic particle calculation module according to the working conditions of the internal combustion engine represented by the variable of the rotating speed and the fuel injection quantity of the internal combustion engine; a water temperature correction module queries a corresponding MAP table according to the cooling water temperature of the internal combustion engine to obtain a water temperature correction coefficient, a transient working condition correction module calculates and obtains a transient air-fuel ratio deviation according to the rotating speed of the internal combustion engine, the fuel injection quantity and the air input of the internal combustion engine, and the transient working condition correction coefficient is obtained by querying the corresponding MAP table according to the transient air-fuel ratio deviation value; the particle flow correction calculation module corrects the steady-state working condition basic particle flow calculated by the basic particle calculation module through the water temperature correction coefficient calculated by the water temperature correction module and the transient working condition correction coefficient calculated by the transient working condition correction module to obtain the particle flow entering the particle filter.
2. The particulate filter control system for an internal combustion engine according to claim 1,
the oxygen flow module is used for calculating the oxygen flow of oxygen in the exhaust gas discharged from the outlet of the exhaust manifold after the oxygen in the exhaust gas is reacted by the oxidation catalyst and enters the particulate filter; the device comprises an exhaust manifold outlet oxygen content coefficient calculation module and a DOC outlet oxygen flow calculation module; the oxygen flow at the outlet of the exhaust manifold of the internal combustion engine is determined by the transient air-fuel ratio of the internal combustion engine and the exhaust gas recirculation rate of the internal combustion engine, and the combustion control parameters of the internal combustion engine are obtained by inquiring an oxygen content coefficient in the exhaust gas obtained by a corresponding MAP table through an oxygen content coefficient calculating module at the outlet of the exhaust manifold or obtaining the oxygen content coefficient in the exhaust gas through calculation according to a combustion model; in the DOC outlet oxygen flow calculation module, the mass flow of the exhaust gas at the outlet of the exhaust manifold is multiplied by the oxygen content coefficient at the outlet of the exhaust manifold obtained by the exhaust manifold outlet oxygen content coefficient calculation module to obtain the oxygen flow entering the oxidation catalyst; inquiring corresponding MAP (MAP) according to the oxygen flow entering the oxidation catalyst and the temperature of the oxidation catalyst carrier or calculating the reaction rate of the obtained oxygen in the oxidation catalyst according to a chemical reaction model of the oxidation catalyst; checking the corresponding MAP according to the reaction rate of the oxygen in the catalyst and the post-injection oil quantity to obtain the oxygen quantity consumed by the oxidation catalyst in the reaction per unit time; the oxygen flow entering the oxidation catalyst subtracts the oxygen consumed by the oxidation catalyst in unit time to obtain the oxygen flow at the outlet of the oxidation catalyst, namely the oxygen flow entering the particulate filter.
3. The particulate filter control system for an internal combustion engine according to claim 1,
the nitrogen dioxide flow module multiplies the flow of nitrogen oxide at the exhaust manifold of the internal combustion engine by the conversion rate of the nitrogen oxide in the oxidation catalyst to nitrogen dioxide to obtain the flow of the nitrogen dioxide entering the particulate filter; basic flow of nitrogen oxides at the exhaust manifold of the internal combustion engine is determined by inquiring a corresponding MAP table according to the working conditions of the internal combustion engine represented by the variables of the rotating speed and the fuel injection quantity of the internal combustion engine, and the basic flow of the nitrogen oxides is corrected by considering the exhaust gas recirculation rate and the cooling water temperature of the internal combustion engine at the same time to obtain the flow of the nitrogen oxides at the exhaust manifold of the internal combustion engine; the basic conversion rate of converting the nitrogen oxide in the oxidation catalyst into the nitrogen dioxide is determined by inquiring a corresponding MAP table according to the temperature of the oxidation catalyst and the flow of the nitrogen oxide at an exhaust manifold, and the conversion rate of the nitrogen oxide in the oxidation catalyst into the nitrogen dioxide is obtained after the aging degree coefficient of the oxidation catalyst is corrected; the nitrogen oxide discharged by the internal combustion engine and knowing the flow of the nitrogen oxide at the exhaust manifold enters the oxidation catalyst, and the flow of the nitrogen dioxide at the outlet of the oxidation catalyst, namely the flow of the nitrogen dioxide entering the particulate filter, can be obtained according to the determined conversion rate.
4. The particulate filter control system for an internal combustion engine according to claim 3,
the oxidation catalyst age factor is determined from a query of the corresponding MAP table for the cumulative time that the oxidation catalyst substrate temperature exceeds the age temperature threshold.
5. The particulate filter control system for an internal combustion engine according to claim 1,
the active regeneration module is used for calculating the active reaction efficiency of the particles and the oxygen in the particle filter during the active regeneration of the particle filter by multiplying the basic reaction efficiency of the oxygen and the particles in the particle filter by an active reaction efficiency correction coefficient; the basic reaction efficiency of oxygen and particles in the particle filter is obtained by checking a corresponding MAP or a reaction model according to the reaction conditions in the particle filter represented by the temperature of the carrier of the particle filter and the oxygen flow at the outlet of the oxidation catalyst; the active reaction efficiency correction coefficient is obtained by looking up a corresponding curve characteristic table according to the particle deposition characteristic reflected by the particle cumulant; the reaction rate of the particulates in the particulate filter with oxygen during the active regeneration of the particulate filter, that is, the active regeneration reaction rate of the particulate filter, is obtained by multiplying the accumulation amount of the particulates in the particulate filter by the active reaction efficiency.
6. The particulate filter control system for an internal combustion engine according to claim 1,
the passive regeneration module is used for calculating the reaction rate of particles in the filter and nitrogen dioxide during the passive regeneration of the particulate filter by multiplying the particle accumulation amount in the particulate filter and the passive reaction efficiency in the particulate filter; the passive reaction efficiency in the particulate filter is obtained by checking a corresponding MAP table or a passive reaction model according to the temperature of exhaust gas at the outlet of the oxidation catalyst, the flow rate of nitrogen dioxide entering the particulate filter and the cumulative amount of particulates in the particulate filter; the passive regeneration reaction rate of the particulate filter can be obtained by multiplying the passive reaction efficiency in the particulate filter by the accumulation amount of the particulate in the particulate filter.
7. The particulate filter control system for an internal combustion engine according to claim 1,
the trapping rate module comprises a trapping efficiency calculation module and a trapping rate calculation module; in the trapping efficiency calculation module, the trapping efficiency of the particulate filter is obtained by checking a corresponding MAP table or a trapping efficiency model according to the filtering characteristics represented by the accumulated amount of the particulates in the particulate filter and the total volume of the particulate filter; the trapping rate calculation module multiplies the flow of the particles entering the particle filter by the trapping efficiency of the particle filter calculated by the trapping efficiency calculation module to obtain the trapping rate of the particle filter, namely the mass of the particles trapped in unit time; the particulate filter trapping rate minus the active particulate filter regeneration reaction rate and the passive particulate filter regeneration reaction rate yields the particulate accumulation rate within the particulate filter.
8. The particulate filter control system for an internal combustion engine according to claim 1,
the particle accumulation module comprises a particle integration module; the particle integration module is used for calculating the current particle accumulation amount in the particle filter; when the internal combustion engine is in an operating state, the particle integration module starts to use the particle accumulation integration initial value and the particle accumulation rate to carry out particle mass integration at the moment, and the particle accumulation amount accumulated in the particle filter is calculated; resetting the integral value when the controller sends out a signal for replacing or cleaning the particulate filter, wherein the reset initial value is a filter reset initial value; the controller saves the particulate accumulation amount calculated by the particulate integration module when the internal combustion engine is stopped, and as a particulate accumulation integration initial value for calculation at the next time the internal combustion engine is operated.
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| CN112412600B (en) * | 2020-11-24 | 2021-11-19 | 安徽江淮汽车集团股份有限公司 | Method, device and equipment for monitoring trapping efficiency of particle trap and storage medium |
| CN112395710B (en) * | 2020-12-02 | 2023-11-17 | 潍柴动力股份有限公司 | Correction method and device for carbon loading model |
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| CN114033532B (en) * | 2021-11-08 | 2022-12-30 | 凯龙高科技股份有限公司 | DPF active regeneration period determination method and device, electronic equipment and storage medium |
| CN114033533B (en) * | 2021-11-08 | 2022-11-18 | 凯龙高科技股份有限公司 | DPF active regeneration period determination method and device, electronic equipment and storage medium |
| CN115045743A (en) * | 2022-04-27 | 2022-09-13 | 东风柳州汽车有限公司 | GPF-based oxygen flow calculation method, device, equipment and storage medium |
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