CN101418712B

CN101418712B - Electrically heated particulate filter regeneration using hydrocarbon adsorbents

Info

Publication number: CN101418712B
Application number: CN2008101497711A
Authority: CN
Inventors: E·V·冈策; M·J·小帕拉托尔; F·阿门特
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2007-10-22
Filing date: 2008-09-25
Publication date: 2011-05-11
Anticipated expiration: 2028-09-25
Also published as: DE102008039619A1; CN101418712A

Abstract

An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material selectively heats exhaust passing through the upstream end to initiate combustion of particulates within the PF. A hydrocarbon adsorbent coating applied to the PF releases hydrocarbons into the exhaust to increase a temperature of the combustion of the particulates within the PF.

Description

Use the electrically heated particulate filter regeneration of hydrocarbon adsorbents

The statement of government rights

[0001] the present invention is proposing with about No.DE-FC-04-03AL67635 according to U.S. government and DOE (Department of Energy) (DoE).U.S. government has certain right to the present invention.

Technical field

[0002] the present invention relates to be used for the heated particle filter method and apparatus of (or claiming particle trapper).

Background technique

[0003] description of this section may not constitute prior art just for background information related to the present invention is provided.

[0004] diesel engine has the efficient higher than petrol engine usually, because the compression ratio of diesel fuel increases and energy density is higher.The burn cycle of diesel engine produces particle, normally by the particulate filter (PF) that is arranged in the blast air these particles is filtered out from diesel exhaust gas.Along with the past of time, this PF can become full and must remove the diesel particulate that is captured.In the regenerative process, diesel particulate is in the PF internal combustion.

[0005] some regeneration method are lighted the particulate matter of PF front portion by the front surface heater.Then, utilize PF be heated near surface particulate matter the heat that burning produced or by the heat that exhaust produces that is heated that flows through PF, realize the regeneration of PF no particulate matter.In some cases, the burning of particulate matter has been suppressed in the high flow rate exhaust of flowing through PF, propagates downwards along PF thereby stop.In order to prevent this compacting, the operation of this regeneration method is limited to the low running condition of exhaust flow velocity, as idling conditions or urban transit system running condition.

Summary of the invention

[0006] therefore, the invention provides a kind of vent systems, be used to handle the exhaust that motor produces.This system generally comprises particulate filter (PF), and it filters out particle from exhaust, and wherein, the upstream extremity of PF receives the exhaust that motor is discharged.Thereby the grid of resistance material optionally heats the exhaust of this upstream extremity of flowing through and causes the endocorpuscular burning of PF.Thereby the hydrocarbon adsorbents coating that is coated on the PF is discharged into hydrocarbon the particle burning temperature that improves in the exhaust in the PF.

[0007] on the other hand, the invention provides the method that a kind of particulate filter (PF) that is used for vent systems is regenerated.This method generally comprises: the grid that resistance material is set at the front end of PF; Switch on to heat this grid to resistance material; Cause the particle burning that exists on the PF front surface by being heated grid; Thereby cause the endocorpuscular burning of PF in the heat importing PF with the particle burning generation; And, hydrocarbon improves the particle burning temperature in the exhaust from hydrocarbon adsorbents by being discharged into.

[0008] will obviously find out more suitable application areas of the present invention from the description of this paper.Should be appreciated that detailed description and specific examples just play effect for example, and be not intended to limit the scope of the invention.

Description of drawings

[0009] accompanying drawing described herein just plays effect for example, and never intention limits the scope of the invention.

[0010] Fig. 1 is the theory diagram of exemplary automobile, and this automobile has the particulate filter and the particulate filter regeneration systems of the each side according to the present invention.

[0011] Fig. 2 is the sectional view of exemplary wall stream integral particulate filter.

[0012] Fig. 3 comprises the perspective view of the exemplary front surface of particulate filter, and it shows the various patterns of resistor path.

[0013] Fig. 4 is the front surface perspective view of exemplary particulate filter and heater pad.

[0014] Fig. 5 is the sectional view of particulate filter shown in Figure 2, and it has hydrocarbon adsorbents.

[0015] Fig. 6 is that figure has released according to the present invention the data flowchart of the exemplary particulate filter regeneration systems of each side.

[0016] Fig. 7 is that figure has released according to the present invention the flow chart of the exemplary particulate filter regeneration systems of each side.And being figure, Fig. 8 released the flow chart of exemplary temperature controlling method in the particulate filter regenerating method.

Embodiment

[0017] in fact following description is exemplary and is not intended to limit the present invention, application or purposes.Should be appreciated that and in institute's drawings attached, represent identical or corresponding part and feature with identical reference character.Term used herein " module " is meant specific integrated circuit (ASIC), electronic circuit, carries out the processor of one or more softwares or firmware program (shared, special-purpose or group) and storage, combinational logic circuit and/or other the suitable parts that described function is provided.

[0018], shows the exemplary automobile 10 of the diesel engine system 11 that comprises each side according to the present invention referring now to Fig. 1.Should be appreciated that in fact diesel engine system 11 is exemplary, and particulate filter regeneration systems described herein can be used in having adopted the various engine systems of particulate filter.These engine systems can be but be not limited to G. D. I engine system and homogeneous charge compression ignition engine system.For the ease of discussing, will discuss the present invention with regard to diesel engine system.

[0019] turbocharged diesel system 11 comprises that combustion air and fuel mixture are to produce the motor 12 of driving torque.Air enters this system via air-strainer 14.Air stream is through air-strainer 14 and be inhaled in the turbosupercharger 18.18 pairs of fresh airs that enter system 11 of turbosupercharger compress.Usually, air compression must be big more, and the output of motor 12 is just big more.Then, the pressurized air air-cooler 20 of before entering intake manifold 22, flowing through.

[0020] air in the intake manifold 22 is divided into cylinder 26.Although four cylinders 26 only are shown, be to be understood that system and method for the present invention can use in having the motor of a plurality of cylinders, include but not limited to 2,3,4,5,6,8,10 and 12 cylinders.Should be appreciated that also system and method for the present invention can use in v type air cylinder structure.By fuel injector 28 fuel is sprayed into cylinder 26.Compressed-air actuated heat has been lighted air/fuel mixture.The burning of air/fuel mixture produces exhaust.Exhaust enters vent systems from cylinder 26.

[0021] vent systems comprises gas exhaust manifold 30, diesel oxidation catalyst (DOC) 32 and particulate filter (PF) 34.Alternatively, EGR valve (not shown) with a part of exhaust gas recirculatioon back in the gas manifold 22.All the other exhausts are introduced in the turbosupercharger 18 and drive turbine.This turbine has promoted the compression of the fresh air that comes out from air-strainer 14.Exhaust is flowed out from turbosupercharger 18, flows through DOC32 and PF34.DOC32 is according in the after-combustion air fuel ratio oxidation being carried out in exhaust.PF34 receives the exhaust of coming out from DOC32 and the particulate matter that exists the exhaust is carried out trap filter

[0022] control module 44 is controlled motor 12 and PF regeneration according to various detection information and/or model information.In more detail, the particulate matter load capacity of control module 44 estimation PF34.When the particulate matter load capacity of estimation reaches threshold value (as, the particulate matter of 5 grams per liters) and exhaust flow velocity and is in the prespecified range, start regenerative process thereby control the electric current of supplying with PF34 by power supply 46.Change the endurance of regenerative process according to the particulate matter quality in the PF34.Expect that regenerative process can continue 1-6 minute.Yet, only switch in the initial period of regenerative process.In more detail, electric energy to the place ahead of PF34 heating one period phase presentation time (as, 1-2 minute).Exhaust to the front surface of flowing through is heated.The residue period that utilization is finished regenerative process by near the heat of the burning generation of the particulate matter the face that is heated of PF34 or the heat that is heated the exhaust generation of the PF34 that flows through.

[0023] in some cases, the burning meeting of PF34 no particulate matter is by some motor operation conditions compacting.For example, the motor accelerated events may be suppressed regeneration.In order to prevent this compacting, PF34 has hydrocarbon adsorbents, and this will further discuss hereinafter.Control module 44 is carried out pretreatment with fuel to hydrocarbon adsorbents according to sensor signal and/or modeling data, and particulate filter regenerating method of the present invention and system are carried out pretreatment.Thereby the pretreatment of fuel has improved burning level in the PF has prevented compacting to burning.

[0024] in various embodiments, exhaust gas temperature sensor 47 produces exhaust temperature signal based on delivery temperature.Mass Air Flow sensor 48 produces exhaust signal based on the air that enters or discharge motor 12.Electric current and/or voltage transducer 49 produce electric current and/or voltage signal based on power supply 46 to voltage and/or the electric current that PF34 provides.Lambda sensor 51 produces the oxygen content signal based on the oxygen content in the exhaust.In various embodiments, control module 44 receives these signals and with fuel PF34 is carried out pretreatment, controls combustion temperature simultaneously and makes heat not too high.The fuel pretreatment can by for example after burn cycle through for example fuel injector 28 or in exhaust the rearmounted fuel injector 53 of burner oil finish to the exhaust burner oil.In other different embodiments, the fuel pretreatment is for example taking place in the engine cold starting event procedure easily, and this moment, the air/fuel ratio was generally dense.

[0025] especially with reference to Fig. 2, PF34 is preferably the integral particulate filter and comprises closed cell/duct 50 and open cells/duct 52 alternately.These unit/ducts 50,52 are the square-section normally, runs through these parts vertically.The wall 58 of PF34 is preferably the ceramic honey comb wall of the porous of being made by cordierite material and forms.Should be appreciated that any ceramic honey comb material all within the scope of the present invention.Adjacent duct is alternately to block an end, shown in 56.This just forces diesel particulate to pass the carrier wall of porous, and it serves as mechanical filter.Particulate matter is deposited in the sealing duct 50, and exhaust is discharged through open cell channels 52.Particulate matter 59 flows into PF34 and is trapped in wherein.

[0026] purpose in order to regenerate, the grid 64 that comprises resistance material is attached on the place ahead outer surface of PF34, is called front surface.Switch on to resistance material and to produce heat energy.Should be appreciated that and to adopt the thick film heating technology that grid 64 is attached on the PF34.For example, can coat heating material such as silver or nichrome at the front surface of PF34 is corroded then or adds the last layer shade.In other different embodiments, grid 64 is made up of resistance material such as stainless steel, and the mode of utilizing binder or being press fit into PF34 is attached on the PF34.

[0027] should be appreciated that also resistance material is applicable as various single path or multipath pattern, as shown in Figure 3.Some sections that can remove resistance material produce path.In various embodiments, as shown in Figure 4, stick the heater pad 70 of porous at the front surface of PF34.In above-mentioned arbitrary embodiment, the exhaust band that flows through PF34 the heat energy that produces at the PF34 front surface along the duct 50,52 down a bit of distances.The heat energy that increases has been lighted near the particulate matter of inlet of PF34.Then, thus the heat that particle burning produced is conducted through the burning that PF34 causes all the other particles in the PF34.

[0028], as mentioned above, on PF34, scribbles hydrocarbon adsorbents coating 72 especially with reference to Fig. 5.In various embodiments, as shown in the figure, hydrocarbon adsorbents coating 72 is adorned closelyer than the rear end of PF34 at the PF34 front end.According to expectation ground, the rear end of the density of hydrocarbon adsorbents coating 72 from the front end of PF34 to PF34 is to successively decrease.

[0029] during various motor operation conditionss, when the cold machine of PF34 moves, hydrocarbon adsorbents coating 72 storage hydrocarbons.When being heated, therefore the hydrocarbon of PF34 front-end stores is released, and makes particulate matter can add fuel on the ground that the easiest quilt of flame beacon face extinguishes.For example, after beginning regeneration, flame beacon face spreads and passes hydrocarbon adsorbents coating 72.Thereby hydrocarbon adsorbents coating 72 is discharged into hydrocarbon and improves regeneration temperature in the burning particles.More can resist the incident of extinguishing than thermal-flame, just as high-temperature exhaust air stream.When 72 of hydrocarbon adsorbents coatings were located at PF34 anterior, along with flame beacon face spreads through hydrocarbon adsorbents coating 72, hot acceleration reduced, and reduces the heat dissipation of PF34 rear end thus.

[0030] referring now to Fig. 6, data flowchart figure has released the various embodiments of particulate filter regeneration systems, and this system is embedded in the control module 44.The various embodiments of particulate filter regeneration systems of the present invention can have the submodule in the control module 44 of being embedded in of any amount.According to expectation ground, submodule shown in Figure 6 can merge and/or further divide similarly to control the regeneration of PF34.The input value of system can detect from automobile 10 (Fig. 1), and other control module in automobile 10 (Fig. 1) receives, and/or is determined by other submodule (not shown) in the control module 44.In various embodiments, the control module 44 of Fig. 6 has regeneration control module 80, fuel control module 82 and temperature control modules 84.

[0031] regeneration control module 80 reception particulate matter quality and grades 86 and exhaust flow velocity 88 are as input value, and this particulate matter quality and grade indicates the estimated value that is accumulated in the particulate matter among the PF34 (Fig. 1).According to particulate matter quality and grade 86 and exhaust flow velocity 88, regeneration control module 80 determines whether and need regenerate.For example, if accumulation particulate matter quality and grade 86 height and exhaust flow velocity 88 are enough to the continuity burning, regeneration control module 80 need be regenerated with regard to determining.Regenerate if desired, regeneration control module 80 just is provided with reproduced state 90 and need regenerates to indicate.In various embodiments, reproduced state 90 can be to enumerate, and its numerical value indicates at least not to be needed to regenerate, need regenerate and ongoing regeneration.

[0032] regeneration control module 80 can also receive fuel state 92 and combustion temperature 93 as input value.In case indicating, fuel state 92 finished fuel pretreatment (as mentioned below), regeneration control module 80 just produces heater control signal 94, the surface that the electric current of PF34 (Fig. 1) heats PF34 (Fig. 1) is led in its control, and reproduced state 90 is arranged to indicate the regeneration well afoot.For example, in case finished regeneration, finished regeneration when combustion temperature 93 indicates, regeneration control module 80 just is arranged to reproduced state 90 to indicate and has been finished regeneration.

[0033] fuel control module 82 receives reproduced state 90 as input value.Need regenerate if reproduced state 90 indicates, fuel control module 82 just produces fuel control signal 95, sprays into blast air or directly sprays in the PF34 (Fig. 1) by control fuel PF34 (Fig. 1) is carried out pretreatment.In case finished the fuel pretreatment, fuel control module 82 just is arranged to fuel state 92 to indicate and has been finished the fuel pretreatment.For example, fuel state 92 is made as and equals TRUE when having finished the fuel pretreatment, and fuel state 92 is made as and equals FALSE when not finishing the fuel pretreatment.

[0034] temperature control modules 84 receives reproduced state 90, oxygen concentration 96, exhaust flow velocity 98, delivery temperature 100 and grid temperatures 102 as input value.In various embodiments, determine grid temperatures 102 according to voltage and/or current signal.When reproduced state 90 indicated the regeneration well afoot, temperature control modules 84 evaluation oxygen concentrations 96, exhaust flow velocity 98, delivery temperature 100 and grid temperatures 102 were estimated combustion temperature 93.If combustion temperature 93 is too high, temperature control modules 84 just by fuel parameter 104 and/or air parameter 106 control supply engines 12 (Fig. 1) thus fuel and/or air restriction maximum combustion temperature, and prevent to damage PF34 thus.

[0035] referring now to Fig. 7, flow chart figure has released exemplary particulate filter regenerating method, and its particulate filter regeneration systems by Fig. 6 of the each side according to the present invention is carried out.According to expectation ground, the order of the performed step of exemplary particulate filter regenerating method can change, only otherwise change essence of the present invention.Exemplary particulate filter regenerating method is periodically carried out or according to the particular event predetermined running at the control module run duration.

[0036] in an example, this method begins at 200 places.At 210 places, PF34 (Fig. 1) is passed a judgement to determine whether and need regenerate.If expired and need regenerate, just in the temperature of estimation of 210 and 220 places and evaluation PF34 at 210 PF34 of place (Fig. 1).If be lower than predetermined threshold temperature and fuel of no use carries out pretreatment to PF34 (Fig. 1) in 230 place's temperature, just with fuel PF34 (Fig. 1) carried out pretreatment at 240 places.Power to begin regeneration to PF34 (Fig. 1) at 250 places.Yet,, just do not carry out pretreatment and power to begin regeneration to PF34 (Fig. 1) if be higher than temperature threshold or at 240 places PF34 carried out pretreatment in 220 place's combustion temperature.

[0037] at the regeneration period at 260 places, monitors combustion temperature 93 at 270 places.If, just carry out the maximum combustion temperature that temperature is controlled the regeneration period that limits 270 places at 270 place's combustion temperature, 93 height (just being higher than predetermined threshold).Yet,, just continue regeneration if the combustion temperature 93 at 270 places is normal.After 260 places have finished regeneration, just finish this method at 292 places.

[0038] referring now to Fig. 8, flow chart figure has released the exemplary temperature controlling method of particulate filter regenerating method, and its particulate filter regeneration systems by Fig. 6 of the each side according to the present invention is carried out.According to expectation ground, the order of the performed step of exemplary temperature controlling method can change, only otherwise change essence of the present invention.The exemplary temperature controlling method is periodically carried out or according to the particular event predetermined running at the control module run duration.

[0039] in an example, this method begins at 300 places.In the combustion temperature 93 of 310 places estimation particulate matter and at 320 places it is evaluated.If 320 place's combustion temperature 93 too high (just being higher than threshold value) just limit combustion temperature 93 at 330 places by control engine parameter such as engine air and/or fuel etc.Finish this method at 340 places.

[0040] those skilled in the art can know from description above now, can implement broad teachings of the present invention in a variety of forms.Therefore, although described the present invention with specific examples,, therefore actual range of the present invention can not be restricted, because can clearly obtain other modification by research accompanying drawing, specification and following claim for a person skilled in the art.

Claims

1. vent systems that is used to handle the exhaust that motor produces comprises:

Particulate filter, it filters out particle from exhaust, and wherein, the upstream extremity of particulate filter receives the exhaust that motor is discharged;

The grid that resistance material is made, thus its exhaust of optionally heating this upstream extremity of flowing through causes the endocorpuscular burning of particulate filter; And

Be coated in the hydrocarbon adsorbents coating on the particulate filter, thereby it is discharged into hydrocarbon the particle burning temperature that improves in the exhaust in the particulate filter.

2. vent systems as claimed in claim 1, wherein, the hydrocarbon adsorbents coating is coated on first minor segment of particulate filter by first density.

3. vent systems as claimed in claim 2, wherein, the hydrocarbon adsorbents coating is to be coated on second minor segment of particulate filter by second density, and wherein, first density is greater than second density.

4. vent systems as claimed in claim 3, wherein, first minor segment is first distance from the particulate filter upstream extremity, second minor segment is the second distance from the particulate filter upstream extremity, and wherein, second distance is greater than first distance.

5. vent systems as claimed in claim 1 also comprises control module, and it optionally controls the injection of fuel to the exhaust of flowing through particulate filter, and wherein, hydrocarbon adsorbents is stored from the hydrocarbon in the fuel.

6. vent systems as claimed in claim 5, wherein, control module is controlled the injection of fuel by the fuel injector of control motor.

7. vent systems as claimed in claim 5, wherein, control module is arranged in the injection that rearmounted fuel injector in the blast air is controlled fuel by control.

8. vent systems as claimed in claim 5, wherein, after fuel had sprayed in the exhaust, control module control began regeneration to the energising of particulate filter.

9. the method for the particulate filter of the vent systems that is used to regenerate comprises:

The grid that provides resistance material to make at the front end place of particulate filter;

Switch on to heat this grid to resistance material;

Cause the particle burning that exists on the particulate filter front surface by heated grid;

Thereby by causing the endocorpuscular burning of particulate filter in the heat importing particulate filter of exhaust with the particle burning generation; And

By hydrocarbon is discharged into the temperature that improves particle burning in the exhaust from hydrocarbon adsorbents.

10. method as claimed in claim 9 also comprises the hydrocarbon adsorbents coating to particulate filter is provided.

11. method as claimed in claim 10, wherein, first minor segment that provides the hydrocarbon adsorbents coating to be included in particulate filter provides the hydrocarbon adsorbents coating by first density.

12. method as claimed in claim 11, wherein, second minor segment that provides the hydrocarbon adsorbents coating to be included in particulate filter provides the hydrocarbon adsorbents coating by second density, and wherein, first density is greater than second density.

13. method as claimed in claim 12, wherein, provide the hydrocarbon adsorbents coating also to be included on first minor segment of front end first distance of particulate filter by first density in first minor segment hydrocarbon adsorbents coating is provided, wherein, provide the hydrocarbon adsorbents coating also to be included on second minor segment of the front end second distance of particulate filter by second density in second minor segment hydrocarbon adsorbents coating is provided, and wherein, second distance is greater than first distance.

14. method as claimed in claim 9 also comprises:

Optionally control the injection of fuel to the exhaust of flowing through particulate filter; And

By the hydrocarbon of hydrocarbon adsorbents storage from fuel.

15. method as claimed in claim 14 wherein, is optionally controlled the fuel injection and is comprised the injection of optionally controlling fuel by the fuel injector of control motor.

16. method as claimed in claim 14 wherein, is optionally controlled fuel and is sprayed and to comprise by control and be arranged in the injection that rearmounted fuel injector in the blast air is controlled fuel.

17. method as claimed in claim 9 also is included in after fuel sprayed in the exhaust, control begins regeneration to the energising of particulate filter.