CN103133105A

CN103133105A - Controlling soot burn in a diesel particulate filter (dpf) of a vehicle

Info

Publication number: CN103133105A
Application number: CN2012104438938A
Authority: CN
Inventors: K·福特; J·瑞特; J·布罗姆哈姆; N·H·奥珀斯盖; J·道纳利
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2011-11-24
Filing date: 2012-11-08
Publication date: 2013-06-05
Anticipated expiration: 2032-11-08
Also published as: DE102012221337A1; RU2622586C2; GB201120267D0; CN103133105B; RU2012148815A; GB2496876B; GB2496876A

Abstract

A method of controlling soot burn in a diesel particulate filter (DPF) of a vehicle comprises measuring pressure difference across the DPF, normalizing the measured pressure difference across the DPF, deriving a gradient value from at least one change in the measured pressure difference across the DPF, and controlling regeneration of the DPF in response to the derived gradient value.

Description

The detection of carbon-smoke combustion in vehicle

Technical field

The present invention relates to detect the method and apparatus of carbon-smoke combustion in vehicle.Particularly but not exclusively, the present invention relates to detect the not controlled or unacceptable speed of carbon-smoke combustion in the diesel particulate filter (DPF) of vehicle.

Background technique

But the operation of known diesel engines is tended to have more Economy the shortcoming that can run into the discharging aspect.Diesel engine had complete mixing air of time and fuel seldom before igniting.As a result, the exhaust of diesel engine comprises imperfect combustion fuel, and it is called as particulate matter.

Known use DPF physically captures these particulates.But, the particulate that the soot that DPF easily is aggregated fills up and must capture by catalytic oxidation and repeatedly being regenerated.This makes the temperature of DPF raise.

But, when the temperature of DPF raise, cracking or the fusing of DPF matrix can occur in some cases.For example, the exhaust flow rate that surpasses critical value and pass DPF when soot accumulation is by idling or low load engine operating condition (for example when vehicle slide) and during reduction, the exothermic reaction meeting of carbon and oxygen is too fast.In these cases, but exhaust comprises the oxygen of high percentage is in little overall flow speed, and this convection current that has reduced hot basal body is cooling.In addition, the heat that is produced by exothermic reaction has promoted further oxidation and has therefore produced more heat, and this process is known as " thermal runaway (thermal runaway) ".

Multiple condition can affect the speed that particulate matter assembles and therefore control comparatively difficulty of this speed in DPF.These conditions comprise engine operating condition, mileage, driving style, road conditions etc., and certainly, much these conditions will dynamic change during route.

Made the multiple thermal runaway of attempting before predicting and stoping.Usually, these have related to the temperature of measuring DPF, thereby provide indication when thermal runaway may begin, sometimes as the function of soot content, oxygen concentration, exhaust flow rate etc.For example, in Yezerets US2007/0130921 under one's name, hot gradient/hot slope (thermal ramp) is calculated for and controls regeneration.

Yet known these are attempted often predicting early enough that the beginning of thermal runaway is in order to take corrective action.There are a plurality of reasons, for example suddenly variation of dpf temperature after thermal runaway has begun for this reason.Therefore and temperature rising meeting is considerably localized, and is difficult to (or excessively late be detected) be detected by the temperature transducer away from described position.In addition, in the dynamic situation of the motor that absolute value continuously changes, relate to the prediction meeting of measuring these absolute values too blunt or produce conversely wrong positive result.

Expectation provides the prediction improvement means that thermal runaway begins.Expectation provides the means that do not rely on temperature reading and/or absolute value.

Summary of the invention

According to the present invention, the method for the carbon-smoke combustion in control diesel oil of vehicle particulate filter (DPF) is provided, described method comprises:

Measure the pressure reduction of DPF both sides;

The pressure reduction of the DPF both sides that standardization is measured;

The Grad of deriving from least one of the standardization pressure reduction of DPF both sides changes; And

At least respond the Grad of deriving and control the regeneration of DPF.

Method can comprise measures the step that the flow of DPF is passed in exhaust.Grad can be at least derived from the variation of the relative extraction flow of variation of the pressure reduction of measuring.

Method can comprise measures the step that the volume flowrate of DPF is passed in exhaust.Grad can be at least from the variation of the volume flowrate of the relative exhaust of variation of measured pressure reduction and derived.

The step that starts dpf regeneration can comprise to the exhaust of passing DPF of flowing and adds catalyzer.

The step of controlling dpf regeneration can comprise and taking corrective action.Corrective action can comprise the temperature that changes DPF.Alternately or additionally, corrective action can comprise the amount of the catalyzer that changes the exhaust that adding flows passes DPF.

Method can comprise the steps: to take corrective action when the Grad of deriving reaches predetermined value at least.

Method can comprise the steps: at least measured pressure reduction reduce take corrective action when speed reaches predetermined value.

Method can comprise the steps: to measure at least one in temperature, soot content and the oxygen concentration parameter of DPF.Method can comprise the steps: to rely at least in part in measured parameter at least one control the regeneration of DPF.

Description of drawings

Only embodiments of the present invention will be described by referring to the drawings by way of example for present general, in the accompanying drawings:

Fig. 1 is the schematic diagram of vehicle;

Fig. 2 is the schematic diagram of motor;

Fig. 3 is the schematic diagram of emission control systems;

Fig. 4 is the test result figure that the time dependent motor of car speed is shown;

Fig. 5 is the test result figure that the time dependent motor of temperature of DPF is shown;

Fig. 6 is the test result figure that the time dependent motor of carbon-smoke combustion is shown;

Fig. 7 is the test result figure that the time dependent motor of oxygen concentration is shown;

Fig. 8 is the test result figure that the time dependent motor of pressure reduction of DPF is shown; And

Fig. 9 is the test result figure that the time dependent motor of standardization pressure reduction of DPF is shown.

Embodiment

Fig. 1 is the schematic diagram of vehicle 1, and vehicle 1 has diesel engine 2, and exhaust flow to emission control systems 20 via outlet pipe 5 thus, and emission control systems 20 comprises diesel particulate filter (DPF) 6 and is expelled to atmosphere via tail pipe 7 thus.

Diesel engine 2 may be operably coupled to electronic controller 3, and electronic controller 3 is carried out various functions, and described function comprises controls timing and the volume that fuel is injected into motor 2 each cylinders.Electronic controller 3 is also controlled the regeneration of DPF 6, and this will describe with more details hereinafter.Electronic controller 3 receives input from a plurality of sources, and described a plurality of sources comprise one or more vehicle sensors 8 and engine sensor 9.

Motor 2 has a plurality of cylinders, and a cylinder in these cylinders 30 is illustrated in Fig. 2.Motor comprises firing chamber 32, and piston 36 is set up wherein and is connected to bent axle 40.Firing chamber 32 is communicated with intake manifold 44 and gas exhaust manifold 5 via intake valve 52 and exhaust valve 54.

Controller 3 is to comprise microprocessing unit (CPU) 102, input/output end port (I/O) 104, ROM (read-only memory) (ROM) 106, the microcomputer of random-access memory (ram) 108 and routine data bus.

With reference now to Fig. 3,, emission control systems 20 is included in the antigravity system 13 of DPF 6 upstreams.Can use various types of catalyzer.The downstream that DPF 6 is provided at antigravity system 13 is used for catching the particulate matter of for example soot that the run duration at motor 2 produces.In case soot accumulation has reached predeterminated level, the regeneration of DPF 6 can be activated.Can be by hot filtration apparatus to realizing filter regeneration with the temperature of very fast speed coal smoke particle.

Provide at least one temperature transducer or thermocouple 21 at DPF 6 places.And, can determine pressure difference signal from

pressure transducer

124 and 126,

pressure transducer

124 and 126 is measured respectively the pressure of downstream and the upstream of DPF6.

And, provide sensor 24 to measure the volume flowrate of the exhaust of passing DPF 6.

In addition, sensor 9 can comprise for the running temperature of the rotational speed of measuring motor 2, motor with at the sensor of the delivery temperature at one or more select locations places.

Storage 108 be processed and/or be stored to data from sensor can by microprocessor unit 102.

Fig. 4 shows the test result that is implemented specially to bring out the thermal runaway in DPF 6.Drawing shows the car speed 200 at test period.The regeneration 202 of DPF 6 was located to be activated at 140 seconds.From 250 seconds to 350 seconds, vehicle 1 slided and then is decelerated to 470 seconds with 2.5% little slope slope 204 decelerations and locates to stop fully.

During deceleration is slided, and in the situation that regeneration 202 occurs, the temperature of DPF 6 is high but to pass the flow rate of exhaust of DPF 6 low.Observe in the bottom of the outlet taper 208 of DPF 6 thermal run away condition 206 occurs, it located burning of filter material and at about 30 seconds after-filter wall cuts since 300 seconds.

Fig. 5 is illustrated in the setting of four thermocouples 21 at outlet taper 208 places of DPF 6 and the hygrogram of being measured by each thermocouple 21.Thermocouple 21 is arranged on the arctic (N), the South Pole (S), the eastern utmost point (E) and the western utmost point (W) of outlet taper 208.During drawing was illustrated in whole thermal run away condition 206, measured temperature only raise as expected gradually, do not entered slow down the impact of the vehicle 1 during sliding and only during thermal run away condition 206 temperature rise rapidly.Therefore, any prediction to thermal runaway based on temperature change can not provide time enough to take corrective action.

In addition, the increase of measured temperature depends on the position of thermocouple 21 very much, wherein is in maximum the increasing of the South Pole (position of thermal destruction) thermocouple 21 records.This shows that the temperature of use measurement is as another restriction of thermal runaway fallout predictor.

Fig. 6 shows the drawing of the measured carbon-smoke combustion 210 that calculates according to the CO2 emission of motor 2 and temperature S(in the South Pole) over time.Carbon-smoke combustion 210 keeps stable and only raises rapidly during thermal run away condition 206, and only slim lead is in measured temperature.Therefore, the prediction based on carbon-smoke combustion 210 can not provide time enough to take corrective action equally.

Fig. 7 is illustrated in DPF 6 before and afterwards measured oxygen concentration 212 and 214 time dependent drawing.Can see oxygen generation concentration at the test period surging, because it is gone up in response to dynamic engine condition largely.After regeneration starts, there is remarkable a decline of oxygen concentration, but after, fluctuation still reaches similar in appearance to regeneration level before.Therefore, measured oxygen concentration is considered to main fallout predictor too unstable and that can not begin as thermal runaway.

Fig. 8 illustrate pressure reduction 220(from before DPF 6 and measured pressure afterwards derive) time dependent drawing.Beginning, pressure reduction 220 surgings, but after beginning regeneration, these fluctuations are reducing aspect amplitude and frequency.Also there was an observable decline in pressure reduction 220 near 250 seconds.This also is illustrated in drawing at carbon-smoke combustion 210() and temperature before.

The pressure reduction 220 at each some place in time can by with data divided by another parameter by standardization.Particularly, the volume flowrate of the exhaust of passing DPF 6 that can measure with correspondence of in time pressure difference data is come standardization.This can carry out by controller 3.This will be called as standardized pressure reduction 230.

Fig. 9 illustrates the time dependent drawing of standardized pressure reduction 230.Have been found that in standardized pressure reduction 230 and do not have surging.Still there was observable decline near 250 seconds.But, be apparent that now the early decline that has near beginning 180 seconds.Have realized that the reliable and early stage fallout predictor that standardized pressure reduction 230 provides thermal runaway to begin.

Therefore, comprise from the variation derivation normalized gradient value of the measured pressure reduction of DPF 6 both sides according to the method for the carbon-smoke combustion in control according to the present invention DPF 6, and control the regeneration of DPF 6 based on the Grad of this derivation.This Grad can be by standardization DPF 6 both sides measured pressure reduction and derived.Particularly, can be by data be come the standardization pressure difference data divided by the measured volume flowrate of the correspondence of the exhaust of passing DPF 6.

Controller 3 can from the currency of standardized pressure reduction 230 and one or more early value come the normalized Grad.Although this does not provide indication the earliest, it has avoided the relatively poor prediction based on the actual value that still has minor swing.

Can be added into the regeneration that the mobile catalytic amount that passes the exhaust of DPF 6 realizes controlling based on the standardized Grad of this derivation DPF 6 by temperature and/or the control that for example changes DPF 6.For example, when the normalized gradient value of deriving reached predetermined large threshold value, controller 3 can reduce the temperature of DPF 6 and/or reduce to be added to the amount of catalyzer of the exhaust of passing DPF 6 of flowing.

Although specific embodiments of the invention below have been described, described embodiment have been left in understanding still may fall within the scope of the invention.

Claims

1. a diesel particulate filter of controlling vehicle is the method for the carbon-smoke combustion in DPF, and described method comprises:

Measure the pressure reduction of described DPF both sides;

The described measurement pressure reduction of the described DPF of standardization both sides;

At least from the variation derivation Grad of the standardization pressure reduction of described DPF both sides; And

At least control the regeneration of described DPF in response to the Grad of described derivation.

2. the method for claim 1, comprise the steps: to measure the flow of the exhaust of passing described DPF, and wherein said Grad is at least from the variation of the relative extraction flow of variation of measured pressure reduction and derive.

3. method as claimed in claim 1 or 2, comprise the steps: to measure the volume flowrate of the exhaust of passing described DPF, and wherein said Grad is at least from the variation of the relative exhaust volume flow of the variation of measured pressure reduction and derive.

4. as the described method of above arbitrary claim, the step of wherein controlling described dpf regeneration comprises and taking corrective action.

5. method as claimed in claim 4, wherein said corrective action comprise the temperature that changes described DPF place.

6. method as described in claim 4 or 5, wherein said corrective action comprise the catalytic amount that changes the exhaust that being added into flows passes described DPF.

7. as any described method of claim in claim 4 to 6, comprise the steps: to work as at least when the Grad of deriving reaches predetermined value and take corrective action.

8. as any described method of claim in claim 4 to 6, comprise the steps: at least when described standardized pressure reduction reduce take corrective action when speed reaches predetermined value.

9. as the described method of above arbitrary claim, comprise the steps: to measure at least one in temperature, soot content and the oxygen concentration parameter at described DPF place, and wherein said method comprises the steps: that at least part of at least one based in measured parameter control the regeneration of described DPF.

10. a diesel particulate filter of controlling vehicle is the method for the carbon-smoke combustion in DPF, and described method comprises:

Measure the pressure reduction of described DPF both sides;

At least from the variation derivation Grad of the pressure reduction of described DPF both sides;

The described Grad of standardization; And

At least control the regeneration of described DPF in response to described standardized Grad.

11. method as claimed in claim 10 comprises the steps: to measure the flow of the exhaust of passing described DPF, and wherein said standardized Grad is to derive by the variation with the relative extraction flow of variation of measured pressure reduction at least.

12. method as described in claim 10 or 11, comprise the steps: to measure the volume flowrate that described DPF is passed in exhaust, and wherein said standardized Grad is by deriving with the variation of the relative exhaust volume flow of the variation of measured pressure reduction at least.