CN109083720B - Diesel vehicle DPF active regeneration temperature control method - Google Patents
Diesel vehicle DPF active regeneration temperature control method Download PDFInfo
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- CN109083720B CN109083720B CN201810837066.4A CN201810837066A CN109083720B CN 109083720 B CN109083720 B CN 109083720B CN 201810837066 A CN201810837066 A CN 201810837066A CN 109083720 B CN109083720 B CN 109083720B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
- F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
- F01N3/0253—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases
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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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- 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
Abstract
A diesel vehicle DPF active regeneration temperature control method sequentially comprises the following steps: (1) reading DOC inlet temperature T1 and DPF inlet temperature T2 before oil injectionOriginal sourceSelecting DPF inlet regeneration target temperature T3, calculating or selecting initial oil injection quantity q of an HC injection unit (9), and injecting oil to the DOC (1) inlet according to the initial oil injection quantity q; (2) DPF inlet temperature T2 is read againkThe next fuel injection quantity q of the HC injection unit (9) is redeterminedk+1(ii) a (3) Adjusting the fuel injection quantity injected to the DOC (1) inlet to the next fuel injection quantity q determined in the step (2)k+1(ii) a (4) DPF inlet temperature T2 is read againkThe next fuel injection quantity q of the HC injection unit (9) is redeterminedk+1(ii) a (5) And (4) repeating the step. The quick regeneration of the DPF is realized by less fuel consumption and better regeneration temperature, and the regeneration efficiency of the DPF is higher.
Description
Technical Field
The invention relates to a regeneration method of a particle catcher for purifying engine tail gas, in particular to a control method of the DPF active regeneration temperature of a diesel vehicle. Belongs to the technical field of engine tail gas purification,
background
Particulate matter is one of the major pollutants in diesel exhaust emissions. The national six emission regulations not only tighten the PM mass emission limit by 67%, but also increase the limit on the solid particulate matter PN concentration. To meet stringent PM and PN emission requirements, diesel particulate traps DPF are currently recognized as an aftertreatment device that can effectively eliminate diesel emission particulates. Diesel engine DPF regeneration control is one of the key technologies of the aftertreatment of the national six diesel engines. Because the emission control requirements on low-speed and low-load working regions are increased by the national six-emission standard, the overall exhaust temperature of a general diesel engine is lower, and the exhaust temperature of the engine can not reach the ignition temperature of particles under most working conditions, so that the exhaust temperature needs to be increased by fuel oil injected in a cylinder or behind an exhaust pipe to realize regeneration. The constant variation of the engine operating conditions makes temperature control during regeneration more difficult.
The regeneration temperature control method of the DPF of the diesel engine enables the temperature of the inlet of the DPF to be controlled at a reasonable regeneration target temperature, and the DPF can complete the whole regeneration process safely and reliably without influencing each performance of the engine, so that the regeneration temperature control method of the DPF of the diesel engine is indispensable in a DPF regeneration control system. The most key point of DPF regeneration control is to ensure the stability and accuracy of temperature control in the regeneration process, and the premise for realizing the aim is to ensure the stability and accuracy of DPF inlet temperature control. Chinese patent publication No.: CN 107100703 a, published: 29/8/2017, the invention is named as a method for controlling the DPF regeneration temperature of a non-road diesel engine combustor, and the method comprises the steps of setting the target regeneration temperature of the DPF; the DPF controller judges a DPF regeneration temperature difference which is a difference value between the actual temperature of the DPF and the target regeneration temperature of the DPF; the DPF controller converts the DPF regeneration temperature difference into the size of exhaust pipe fuel injection amount through a feedforward PID controller, the fuel injection amount performs chemical reaction on the DOC catalyst to generate temperature, the DPF catalyst is heated to obtain the DPF actual temperature and DPF regeneration temperature difference, and DPF regeneration temperature closed-loop control based on the target regeneration temperature is completed. Under various working conditions of the diesel engine, the error between the actual temperature of the inlet of the DPF catalyst and the target regeneration temperature of the DPF can be controlled within 25 ℃, and the reliable regeneration temperature management of the DPF system under various working conditions is realized. However, this method has the following disadvantages: the difference between the actual temperature of the DPF inlet and the target regeneration temperature is about 25 ℃, the error between the actual temperature and the target regeneration temperature is large, the temperature fluctuation range during DPF regeneration is large, and the regeneration time is prolonged; secondly, the calculation mode is complex, the parameters needing to be calibrated are many, including a proportional amplification factor, an integral amplification factor, a differential amplification factor and the like, the artificially determined coefficients are too many, the formula is more and complex, the consistency of the calculation result and the actual working condition is poor, and the control precision is low.
Disclosure of Invention
The invention aims to overcome the defects and shortcomings of large regeneration temperature control error, complex calculation formula, multiple calibration parameters and poor control consistency in the prior art, and provides a diesel vehicle DPF active regeneration temperature control method. The method has the advantages of simple calculation method, less sampling parameters, better matching with the actual working condition, higher control precision, good adaptability and lower regenerative oil consumption.
To achieve the above object, the technical solution of the present invention is as follows:
the temperature control method for the active regeneration of the DPF of the diesel vehicle comprises the following steps of:
(1) sampling and reading DOC inlet temperature T1 and DPF inlet temperature T2 before oil injectionOriginal sourceSelecting a DPF inlet regeneration target temperature T3, calculating or selecting an initial oil injection quantity q of the HC injection unit, and controlling the HC injection unit to inject oil to the DOC inlet according to the initial oil injection quantity q;
(2) resampling and reading DPF inlet temperature T2kRe-determining next fuel injection quantity q of HC injection unitk+1；
Next fuel injection quantity q of HC injection unitk+1Calculated according to the following formula:
qk+1＝q+qbk+1；
wherein: qbk+1＝q*(T3-T2k)/(T2k–T2Original source)；
In the formula (I);
qk+1-next injection quantity of HC injection unit;
q- - - -initial fuel injection amount of the HC injection unit;
qbk+1-next compensated injection of fuel by the HC injection unit;
T2k-DPF inlet temperature read for this sampling;
T2original source-DPF inlet temperature read from pre-injection sampling;
t3- -DPF inlet regeneration target temperature;
k is the sampling frequency of DPF inlet temperature T2 after initial oil injection, wherein k is 1 in the step;
(3) adjusting the fuel injection amount of HC injection unit to inject HC injection unitAdjusting the fuel injection quantity of the DOC inlet from the initial fuel injection quantity q to the next fuel injection quantity q determined in the step (2)k+1；
(4) Resampling and reading DPF inlet temperature T2kIncreasing the sampling time K of DPF inlet temperature T2 after initial oil injection once, and simultaneously determining the next oil injection quantity q determined last timek+1As the current fuel injection quantity qkRe-determining next fuel injection quantity q of HC injection unitk+1；
Next fuel injection quantity q of HC injection unitk+1Calculated according to the following formula: q. q.sk+1＝qk+qbk+1；
Wherein: qbk+1＝qk*(T3-T2k)/(T2k–T2Original source)；
In the formula (I);
qk+1-k +1 shots of HC injection unit;
qk-the number of k injections of the HC injection unit;
qbk+1-k +1 compensated injection quantities of the HC injection unit;
T2k-k sample readings of DPF inlet temperature;
T2original source-DPF inlet temperature read from pre-injection sampling;
t3- -DPF inlet regeneration target temperature;
k- -the number of samples of DPF inlet temperature T2 after initial injection, k being 2, 3, 4, 5 …;
adjusting the oil injection quantity of the HC injection unit, and adjusting the oil injection quantity of the HC injection unit injected to the DOC inlet according to the current oil injection quantity qkAdjusted to the next fuel injection quantity qk+1；
(5) And (4) repeating the step.
In the step (1), the DPM fuel injection pump is controlled by the regeneration controller DCU, and the HC injection unit is controlled to inject fuel to the DOC inlet to heat and regenerate the DPF.
The target DPF inlet regeneration temperature in the steps (1), (2), and (4) is 550 to 600 ℃.
The target DPF inlet regeneration temperature in the steps (1), (2), and (4) is 580 ℃.
In the step (2), a calculation formula of the initial fuel injection quantity q of the HC injection unit is as follows:
in the formula, q is initial fuel injection quantity, and the unit is kg/h; c. CpThe exhaust gas ratio constant pressure heat capacity is expressed as J/(kg. DEG C); qmThe unit is kg/h, and the exhaust mass flow is shown as the exhaust mass flow; hfuelThe heat value of the fuel oil is expressed in J/kg; eta is fuel oil oxidation efficiency,%; Δ t0Is the difference between the DPF inlet regeneration target temperature T3 and the DOC inlet temperature T1 before injection in degrees c.
In the step (2) and the step (4), (T3-T2)k) At + 2-2 deg.C, (T3-T2)k)＝0。
In the step (2) and the step (4), the DPF inlet temperature T2k(ii) a Measured DPF inlet temperature T2 before injectionOriginal sourceAnd the temperature value of the DPF inlet regeneration target temperature T3 are both reserved at least two digits after a decimal point.
In the steps (1), (2) and (4), the initial fuel injection quantity q and the next fuel injection quantity q arek+1Next compensation oil injection quantity qbk+1And the fuel injection quantity q of k timeskThe injection quantity values of (A) are all reserved at least two digits after the decimal point.
Before the step (1), reading the operation condition of the engine through a regeneration controller DCU, acquiring the exhaust mass flow of the engine fed back by an engine ECU, the DOC inlet temperature T1 measured by a DOC inlet temperature sensor and the pressure difference between the outlet and the inlet of the DPF measured by a pressure difference sensor arranged at the outlet and the inlet of the DPF, judging whether the three values all reach regeneration trigger values, and triggering regeneration control when the three values all reach respective regeneration trigger values to start the step (1);
the regeneration trigger values of the mass flow of the engine exhaust, the temperature of the DOC inlet and the air pressure difference between the DPF outlet and the DPF inlet are respectively as follows: the DOC inlet temperature is more than or equal to 270 ℃, the engine exhaust mass flow is more than or equal to 200kg/h, and the air pressure difference between the DPF inlet and the DPF outlet is more than or equal to 15 kPa.
In the step (1), after the HC injection unit starts to inject oil according to the initial oil injection quantity q, the pressure difference sensors at the outlet and the inlet of the DPF are detected, and when the pressure difference value between the outlet and the inlet of the DPF is less than or equal to 4kPa, the regeneration controller DCU controls the DPM oil injection pump and controls the HC injection unit to stop injecting oil, so that the regeneration process is completed.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the temperature change trends of the DOC inlet and the DPF inlet, namely the DOC outlet before and after oil injection, the corresponding relation between the last oil injection amount and the DPF inlet temperature is analyzed, the next compensation oil injection amount required by reaching the DPF inlet regeneration target temperature is calculated, the sum of the last oil injection amount and the next compensation oil injection amount is used as the next oil injection amount, the last oil injection amount is adjusted, the DPF inlet temperature is quickly reached and stabilized within the DPF inlet regeneration target temperature range through dynamic adjustment of the oil injection amount, DPF quick regeneration is realized with less fuel consumption and better regeneration temperature, and the DPF regeneration efficiency is higher.
2. The method has the advantages of simple calculation mode of next oil injection amount, few data sampling points, few read data, convenient value taking, no artificially set correction coefficient, good consistency of the calculation result and the actual working condition, convenient and quick adjustment of the oil injection amount, high response speed, higher control precision, no DPF overburning phenomenon, prolonged service life of the DPF, and safe and reliable use.
3. The regeneration target temperature of the invention is 550-600 ℃, when the temperature is lower than 550 ℃, the regeneration efficiency is low, carbon particles on the DPF can not be removed to the lower limit value of the carbon loading capacity in a short time, and when the temperature is higher than 600 ℃, certain damage can be caused to the DPF carrier by high temperature. Therefore, the regeneration temperature range of 550-600 ℃ is selected to ensure that the whole regeneration process is carried out stably, the damage to the carrier is small, the regeneration efficiency is high, and 580 ℃ is the temperature with the best regeneration efficiency.
4. The initial fuel injection quantity calculation formula is simple, DOC fuel oil oxidation efficiency is considered, the error between the target fuel quantity and the actually required fuel quantity is reduced, meanwhile, the parameters in the formula are mostly related to the engine performance and DOC efficiency, the main variables are temperature differences, the universality is high, the DPF inlet temperature can reach or approach the DPF inlet regeneration target temperature quickly, and the time of the DPF entering a better regeneration process is shortened.
5. DPF inlet temperature as described in the present invention; the temperature values of the DPF inlet temperature and the DPF inlet regeneration target temperature measured before oil injection are at least two digits after decimal point. And meanwhile, the oil injection quantity value of the next oil injection quantity, the next compensation oil injection quantity and the oil injection quantity value of the K-time oil injection quantity are at least two digits after decimal point, so that the precision of DPF regeneration temperature control can be further improved.
6. The invention enlarges the error range that the DPF inlet temperature is equal to the DPF inlet regeneration target temperature, can reduce the frequency of adjusting the fuel injection quantity and keep the stability of fuel injection.
7. The regeneration ending condition of the invention is that the air pressure difference value between the inlet and the outlet of the DPF is less than or equal to 4 kPa. When there is a certain amount of carbon particles in the DPF, the operation efficiency of the DPF is higher than that when there is no carbon particles in the DPF, and therefore, since the carbon particles are generally not removed and the certain amount of carbon particles are maintained, the regeneration is terminated at an air pressure difference of 4kPa or less.
Drawings
FIG. 1 is a schematic diagram of a DPF regeneration control architecture according to the present invention;
FIG. 2 is a flow chart of DPF regeneration control of the present invention;
in the figure, 1, DOC, 2, DPF, 3, DOC inlet temperature sensor, 4, DPF inlet temperature sensor, namely DOC outlet temperature sensor, 5, DPF outlet and inlet differential pressure sensor, 6, regeneration controller DCU, 7, engine ECU, 8, DPM fuel injection pump, 9, HC injection unit, T1, DOC inlet temperature, T2, DPF inlet temperature, namely DOC outlet temperature, and delta P, DPF outlet and inlet air pressure difference.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Referring to fig. 1 and 2, in the method for controlling the temperature of diesel vehicle DPF active regeneration according to the present invention, a DOC1 is disposed upstream of the DPF2, an HC injection unit 9 is disposed upstream of the DOC1, normally, an oxidation catalyst, that is, DOC1 and a particulate trap, that is, DPF2, purify exhaust gas discharged from a diesel vehicle engine, so that particulate matters in exhaust gas thereof meet or satisfy national regulation requirements, but after the DPF2 is used for a period of time, fuel is injected through the HC injection unit 9 disposed upstream of the DOC1, so as to generate high temperature active combustion of particulate matters staying in a passage of the DPF2 for regeneration, in the field, conditions for starting the DPF2 to actively regenerate are various, in the regeneration control of the DPF2 according to the present invention, an operation condition of the engine is read through a regeneration controller DCU6, an exhaust mass flow rate of the engine fed back by an engine ECU, a DOC inlet temperature T1 measured by a DOC inlet temperature sensor 3, and a pressure difference sensor 5 disposed at an outlet and an inlet of the engine are collected The air pressure difference between the DPF outlet and inlet judges whether the three values all reach regeneration trigger values, when the three values all reach respective regeneration trigger values, regeneration control is triggered to start the process of active regeneration of the DPF2, and in the invention, the regeneration trigger values of the engine exhaust mass flow, the DOC inlet temperature and the air pressure difference between the DPF outlet and inlet are respectively as follows: the DOC inlet temperature is more than or equal to 270 ℃, the engine exhaust mass flow is more than or equal to 200kg/h, and the air pressure difference between the DPF inlet and the DPF outlet is more than or equal to 15 kPa.
Of course, the present invention may take other forms of DPF triggered regeneration control.
After the DPF2 enters an active regeneration mode, the method for controlling the temperature of the DPF during active regeneration sequentially comprises the following steps:
(1) sampling and reading DOC inlet temperature T1 and DPF inlet temperature T2 before oil injectionOriginal sourceSelecting DPF inlet regeneration target temperature T3, such as T3-580 ℃ or T3-590 ℃, calculating or selecting initial oil injection quantity q of the HC injection unit 9, and controlling the HC injection unit 9 to inject oil to the DOC1 inlet according to the initial oil injection quantity q;
(2) resampling and reading DPF inlet temperature T2kThe next fuel injection quantity q of the HC injection unit 9 is newly determinedk+1；
Next fuel injection quantity q of HC injection unit 9k+1Calculated according to the following formula:
qk+1＝q+qbk+1；
wherein: qbk+1＝q*(T3-T2k)/(T2k–T2Original source)；
In the formula (I);
qk+1next injection quantity of the HC injection unit 9;
q- - - -initial fuel injection amount of the HC injection unit 9;
qbk+1-next compensated injection of fuel by the HC injection unit 9;
T2k-DPF inlet temperature read for this sampling;
T2original source-DPF inlet temperature read from pre-injection sampling;
t3- -DPF inlet regeneration target temperature;
k is the sampling frequency of DPF inlet temperature T2 after initial oil injection, wherein k is 1 in the step;
(3) adjusting the fuel injection quantity of the HC injection unit 9, and adjusting the fuel injection quantity of the HC injection unit 9 injected to the DOC1 inlet from the initial fuel injection quantity q to the next fuel injection quantity q determined in the step (2)k+1；
(4) Resampling and reading DPF inlet temperature T2kThe sampling time k of DPF inlet temperature T2 after initial fuel injection is increased once, and the next fuel injection quantity q determined last time is simultaneously increasedk+1As the current fuel injection quantity qkThe next fuel injection quantity q of the HC injection unit 9 is newly determinedk+1；
Next fuel injection quantity q of HC injection unitk+1Calculated according to the following formula: q. q.sk+1＝qk+qbk+1；
Wherein: qbk+1＝qk*(T3-T2k)/(T2k–T2Original source)；
In the formula (I);
qk+1-k +1 shots of HC injection unit 9;
qk-the k injections of the HC injection unit 9;
qbk+1-k +1 compensated injection quantities of HC injection unit 9;
T2k-k sample readings of DPF inlet temperature;
T2original source-DPF inlet temperature read from pre-injection sampling;
t3- -DPF inlet regeneration target temperature;
k- -the number of samples of DPF inlet temperature T2 after initial injection, k being 2, 3, 4, 5 …;
adjusting the fuel injection quantity of the HC injection unit 9, and adjusting the fuel injection quantity of the HC injection unit 9 injected to the DOC1 inlet from the current fuel injection quantity qkAdjusted to the next fuel injection quantity qk+1；
(5) And (4) repeating the step.
In the step (1) of the invention, the regeneration DPF2 is heated by controlling the DPM fuel injection pump 8 and controlling the HC injection unit 9 to inject fuel to the DOC1 inlet through the regeneration controller DCU 6. Other ways of controlling the HC injection unit 9 to inject fuel into the DOC1 inlet to heat the regenerated DPF2 are also possible.
The target DPF inlet regeneration temperature in step (1), step (2), and step (4) of the present invention is 550 to 600 ℃. The temperature of DPF internal regeneration is reasonable in the range, and the effect of particulate matter combustion purification is good.
Preferably, the target DPF inlet regeneration temperature in step (1), step (2), and step (4) of the present invention is 580 ℃. The regeneration efficiency in the DPF is high, and the phenomenon of over-burning of the DPF cannot occur.
In step (2), the calculation formula of the initial fuel injection quantity q of the HC injection unit 9 is as follows:
in the formula, q is initial fuel injection quantity, and the unit is kg/h; c. CpThe exhaust gas ratio constant pressure heat capacity is expressed as J/(kg. DEG C); qmThe unit is kg/h, and the exhaust mass flow is shown as the exhaust mass flow; hfuelThe heat value of the fuel oil is expressed in J/kg; eta is fuel oil oxidation efficiency,%; Δ t0Is the difference between the DPF inlet regeneration target temperature T3 and the DOC inlet temperature T1 before injection in degrees c.
The initial fuel injection quantity q calculated according to the formula can enable the DPF inlet temperature T2 to reach or approach the DPF inlet regeneration target temperature T3 quickly, and the time for the DPF to enter a better regeneration process is shortened.
Of course, the initial injection quantity q in the present invention can also be selected according to the displacement and power of the engine, such as the DPF regeneration injection quantity of other engines, or the conventional injection quantity is half or 2/3 according to experience.
In the step (2) and the step (4) of the present invention, when (T3-T2)k) At + 2-2 deg.C, (T3-T2)k)＝0。
In the step (2) and the step (4) of the present invention, the DPF inlet temperature T2 isk(ii) a The temperature values of the DPF inlet temperature T2 measured before the injection and the DPF inlet regeneration target temperature T3 both reserve at least two digits after a decimal point.
In the step (1), the step (2) and the step (4), the initial fuel injection quantity q and the next fuel injection quantity q arek+1Next compensation oil injection quantity qbk+1And the fuel injection quantity q of k timeskThe injection quantity values of (A) are all reserved at least two digits after the decimal point.
In the invention, in the step (1), after the HC injection unit 9 starts to inject oil according to the initial oil injection quantity q, the DPF outlet and inlet air pressure difference sensor 5 starts to be detected, and when the air pressure difference value between the DPF outlet and inlet is less than or equal to 4kPa, the regeneration controller DCU6 controls the DPM oil injection pump 8 and controls the HC injection unit 9 to stop injecting oil, thereby completing the regeneration process.
The present invention may also adopt other forms or control methods to stop the injection of the HC injection unit 9 to complete the regeneration process.
The idea of the active regeneration temperature control of the invention is as follows: recording DOC inlet temperature T1 and DPF inlet temperature T2 before oil injectionOriginal sourceInjecting oil to DOC inlet according to initial oil injection quantity q, and recording DPF inlet temperature T2 again after oil injectionkThen, the amount of increase in DPF inlet temperature after injection is calculated (T2)k-T2Original source) The target DPF inlet regeneration temperature T3 and the DPF inlet temperature T2 are calculatedkThe difference of (T3-T2)k)；
Then the initial fuel injection quantity q and the increase quantity of the DPF inlet temperature are determined (T2)k-T2Original source) Dividing, calculating the fuel injection quantity required for increasing one temperature unit, and finally dividing q/(T2)k-T2Original source) Multiplication by (T3-T2)k) Namely, the next compensation oil amount qb which is increased when the next oil injection is carried out and is required to reach the DPF inlet regeneration target temperature T3 is obtainedk+1，
The initial fuel injection quantity q and the next compensation oil quantity qbk+1Adding to obtain the next fuel injection quantity q when the fuel injection quantity is adjustedk+1. The fuel injection quantity is pressed for the next fuel injection quantity qk+1After adjustment, the next fuel injection quantity q is injectedk+1As this injection quantity qkRepeating the temperature reading and calculating process, and continuously adjusting the next fuel injection quantity qk+1So that the next fuel injection quantity q is pressedk+1The DPF inlet temperature raised after the injected fuel is burned is always equal to or close to the DPF inlet regeneration target temperature T3, so that the DPF regeneration effect is good and the regeneration efficiency is improved.
In the fuel injection amount calculation process, the DPF inlet temperature T2 is caused to vary due to the variation in the fuel injection amountkIs greatly changed, resulting in (T3-T2)k) Three situations can occur;
one is DPF inlet temperature T2kLess than the DPF inlet regeneration target temperature T3, i.e. (T3-T2)k) Equal to positive values, in the calculation formula q (T3-T2)k)/(T2k-T2Original source) Due to (T2)k-T2Original source) It is impossible to have a negative value, and the next compensation oil amount qb calculated at this timek+1Also positive. This means that the expression q isk+1＝q+qbk+1Calculated next fuel injection quantity qk+1Greater than initial fuel injection quantity q or current fuel injection quantity qkNext injection quantity qk+1Increase in an attempt to increase the next DPF inlet temperature T2kTo be equal to or close to the DPF inlet regeneration target temperature T3.
Second, DPF inlet temperature T2kEqual to the DPF inlet regeneration target temperature T3, i.e. (T3-T2)k) Equal to zero, in the calculation of formula q (T3-T2)k)/(T2k-T2Original source) In this case, since the numerator is zero, the next compensation oil amount qb calculated at this time isk+1Also zero. This means according to the formula qk+1＝q+qbk+1Calculated next fuel injection quantity qk+1Equal to the initial fuel injection quantity q or the current fuel injection quantity qkThat is, the next injection quantity q at this timek+1Continuously keeping the original initial fuel injection quantity q or the current fuel injection quantity qkAnd no adjustment is made.
Third, DPF inlet temperature T2kGreater than the DPF inlet regeneration target temperature T3, i.e. (T3-T2)k) Equal to a negative value, in the calculation of the formula q (T3-T2)k)/(T2k-T2Original source) Due to (T2)k-T2Original source) It is impossible to have a negative value, and the next compensation oil amount qb calculated at this timek+1Negative values should also be used. This means that the expression q isk+1＝q+(-qbk+1) Calculated next fuel injection quantity qk+1Less than initial oil injection quantity q or current oil injection quantity qkNext injection quantity qk+1Decrease in an attempt to lower the DPF inlet temperature T2kTo be equal to or close to the DPF inlet regeneration target temperature T3.
In the invention, the temperature reading and calculating processes are repeatedly carried out, and the next oil injection quantity q is adjustedk+1The interval time can be set according to the situation, the interval time is long, the sampled and read temperature value is relatively accurate, the time and the period for adjusting the fuel injection quantity are prolonged, the interval time is too short, the fuel injection quantity is adjusted quickly, the sampled and read temperature value has certain fluctuation, the accuracy for adjusting the fuel injection quantity is relatively low, the frequency for adjusting the fuel injection quantity is increased, the time for sampling and adjusting the fuel injection quantity is generally 0.2-5 seconds, wherein, when the time is (T3-T2)k) Equal to zero, namely the original initial fuel injection quantity q or the current fuel injection quantity q is maintainedkWhen the oil injection quantity is not adjusted, the time interval between sampling and adjusting the oil injection quantity can be longer; when (T3-T2)k) Is large, i.e., the DPF inlet temperature T2kWith a large difference from the DPF inlet regeneration target temperature T3, the time between sampling and adjusting the injection quantity should be short.
The process is repeated continuously during the whole regeneration process of the DPF2, and the DPF inlet temperature T2 can be maintained by less fuel injection quantitykAlways remaining at DPF inlet regeneration targetThe temperature T3 is within a suitable range and is near or equal to the set optimal DPF inlet regeneration target temperature T3 until the regeneration process is complete. The regeneration time of the DPF2 is shortened, and the regeneration efficiency of the DPF2 is improved.
In order to improve the accuracy of DPF regeneration temperature control, the DPF inlet temperature T2 provided by the inventionk(ii) a The temperature values of the original DPF inlet temperature T2 and the target DPF inlet regeneration temperature T3 measured before the injection are both reserved at least two digits after decimal point, such as the target DPF inlet regeneration temperature T3 is 580.00 ℃, or the original DPF inlet temperature T2 is 294.352 ℃, or the DPF inlet temperature T2k463.23 ℃ and the like. Meanwhile, the initial fuel injection quantity q and the next fuel injection quantity qk+1Next compensation oil injection quantity qbk+1And the fuel injection quantity q of k timeskThe injected fuel quantity values are all reserved at least two digits after decimal point, for example, the initial injected fuel quantity q is 1.27kg/h, or the injected fuel quantity q next timek+11.42kg/h, or the next compensation oil injection amount qbk+1The fuel injection quantity q is 0.151kg/h or k timesk1.357kg/h, etc.
In order to reduce the frequency of adjusting the fuel injection quantity and maintain the stability of the fuel injection, the invention can also be used when (T3-T2)k) At + 2-2 deg.C, (T3-T2)k) 0. I.e., the DPF inlet temperature T2 is enlargedkEqual to the error range of the DPF inlet regeneration target temperature T3.
The DPF active regeneration temperature control method has the advantages that the control precision is high, the error between the actual temperature at the inlet of the DPF and the target regeneration temperature T3 is small, and the temperature T2 at the inlet of the DPF is lowkThe fluctuation value of the optimal target regeneration temperature T3 can reach about 3-5 ℃, the temperature fluctuation range during DPF regeneration is small, the regeneration time is shortened, the fuel consumption can be reduced by 3% -10%, the phenomenon of DPF overburning can not be generated, the service life of the DPF is prolonged by 10% -15%, and the use is safe and reliable. In addition, the method has the advantages of less read data, no artificially added correction coefficient, good consistency of the calculation result and the actual working condition, simple calculation, convenient and quick adjustment of the fuel injection quantity, high response speed and higher control precision, and the DPF can be used for controlling the diesel fuel injection quantity of the diesel fuel injection unit on the premise of ensuring the measurement precision of the DOC inlet temperature sensor 3 and the DPF inlet temperature sensor 4 and the accuracy of the fuel injection quantity of the HC injection unit 9The control accuracy of the active regeneration temperature can also be improved.
Claims (10)
1. A diesel vehicle DPF active regeneration temperature control method is characterized by comprising the following steps in sequence, wherein a DOC (1) is arranged at the upstream of a DPF (2), and an HC injection unit (9) is arranged at the upstream of the DOC (1):
(1) sampling and reading DOC inlet temperature T1 and DPF inlet temperature T2 before oil injectionOriginal sourceSelecting a DPF inlet regeneration target temperature T3, calculating or selecting an initial oil injection quantity q of the HC injection unit (9), and controlling the HC injection unit (9) to inject oil to the DOC (1) inlet according to the initial oil injection quantity q;
(2) resampling and reading DPF inlet temperature T2kThe next fuel injection quantity q of the HC injection unit (9) is redeterminedk+1；
Next fuel injection quantity q of HC injection unit (9)k+1Calculated according to the following formula:
qk+1＝q+qbk+1；
wherein: qbk+1＝q*(T3-T2k)/(T2k–T2Original source)；
In the formula (I);
qk+1-next injection quantity of HC injection unit (9);
q- - -initial injection quantity of HC injection unit (9);
qbk+1-next compensated injection of fuel by the HC injection unit (9);
T2k-DPF inlet temperature read for this sampling;
T2original source-DPF inlet temperature read from pre-injection sampling;
t3- -DPF inlet regeneration target temperature;
k is the sampling frequency of DPF inlet temperature T2 after initial oil injection, wherein k is 1 in the step;
(3) adjusting the fuel injection quantity of the HC injection unit (9), and adjusting the fuel injection quantity of the HC injection unit (9) injected to the DOC (1) inlet from the initial fuel injection quantity q to the next fuel injection quantity q determined in the step (2)k+1；
(4) Resampling and reading DPF inlet temperature T2kWill initially spray oilThe sampling times K of the inlet temperature T2 of the rear DPF is increased once, and meanwhile, the next fuel injection quantity q determined last time is addedk+1As the current fuel injection quantity qkThe next fuel injection quantity q of the HC injection unit (9) is redeterminedk+1；
Next fuel injection quantity q of HC injection unitk+1Calculated according to the following formula: q. q.sk+1＝qk+qbk+1；
Wherein: qbk+1＝qk*(T3-T2k)/(T2k–T2Original source)；
In the formula (I);
qk+1-k +1 shots of HC injection unit (9);
qk-the k injections of the HC injection unit (9);
qbk+1-k +1 compensation shots of HC injection unit (9);
T2k-k sample readings of DPF inlet temperature;
T2original source-DPF inlet temperature read from pre-injection sampling;
t3- -DPF inlet regeneration target temperature;
k- -the number of samples of DPF inlet temperature T2 after initial injection, k being 2, 3, 4, 5 …;
the fuel injection quantity of the HC injection unit (9) is adjusted, and the fuel injection quantity of the HC injection unit (9) injected to the DOC (1) inlet is adjusted according to the current fuel injection quantity qkAdjusted to the next fuel injection quantity qk+1；
(5) And (4) repeating the step.
2. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: in the step (1), the DPM fuel injection pump (8) is controlled by the regeneration controller DCU (6), and the HC injection unit (9) is controlled to inject fuel to the DOC (1) inlet to heat and regenerate the DPF (2).
3. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: the target DPF inlet regeneration temperature in the steps (1), (2), and (4) is 550 to 600 ℃.
4. The method for controlling temperature of DPF active regeneration of diesel vehicle as claimed in claim 1 or 3, wherein: the target DPF inlet regeneration temperature in the steps (1), (2), and (4) is 580 ℃.
5. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: in the step (2), the calculation formula of the initial fuel injection quantity q of the HC injection unit (9) is as follows:
in the formula, q is initial fuel injection quantity, and the unit is kg/h; c. CpThe exhaust gas ratio constant pressure heat capacity is expressed as J/(kg. DEG C); qmThe unit is kg/h, and the exhaust mass flow is shown as the exhaust mass flow; hfuelThe heat value of the fuel oil is expressed in J/kg; eta is fuel oil oxidation efficiency,%; Δ t0Is the difference between the DPF inlet regeneration target temperature T3 and the DOC inlet temperature T1 before injection in degrees c.
6. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: in the step (2) and the step (4), (T3-T2)k) At + 2-2 deg.C, (T3-T2)k)＝0。
7. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: in the step (2) and the step (4), the DPF inlet temperature T2k(ii) a Measured DPF inlet temperature T2 before injectionOriginal sourceAnd the temperature value of the DPF inlet regeneration target temperature T3 are both reserved at least two digits after a decimal point.
8. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: in the step (1), the step (2) and the step (4), the initial fuel injection quantity q and the next fuel injection quantity q areQuantity qk+1Next compensation oil injection quantity qbk+1And the fuel injection quantity q of K timeskThe injection quantity values of (A) are all reserved at least two digits after the decimal point.
9. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: before the step (1), reading the operation condition of the engine through a regeneration controller DCU (6), acquiring the exhaust mass flow of the engine fed back by an engine ECU, the DOC inlet temperature T1 measured by a DOC inlet temperature sensor (3) and the pressure difference between the outlet and the inlet of the DPF measured by a pressure difference sensor (5) arranged at the outlet and the inlet of the DPF, judging whether the three values all reach regeneration trigger values, triggering regeneration control when the three values all reach respective regeneration trigger values, and starting the step (1);
the regeneration trigger values of the mass flow of the engine exhaust, the temperature of the DOC inlet and the air pressure difference between the DPF outlet and the DPF inlet are respectively as follows: the DOC inlet temperature is more than or equal to 270 ℃, the engine exhaust mass flow is more than or equal to 200kg/h, and the air pressure difference between the DPF inlet and the DPF outlet is more than or equal to 15 kPa.
10. The method of claim 1 for controlling temperature of DPF active regeneration of a diesel vehicle, wherein: in the step (1), after the HC injection unit (9) starts oil injection according to the initial oil injection quantity q, a pressure difference sensor (5) of the DPF outlet and inlet starts to be detected, and when the pressure difference value between the DPF outlet and inlet is smaller than or equal to 4kPa, a regeneration controller DCU (6) controls a DPM oil injection pump (8) and controls the HC injection unit (9) to stop oil injection, so that the regeneration process is completed.
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| CN110242390B (en) * | 2019-05-09 | 2020-07-28 | 上海交通大学 | Regeneration temperature control method and system for diesel particulate filter device |
| CN113985942B (en) * | 2021-10-29 | 2022-07-12 | 东风商用车有限公司 | DPF regeneration temperature control system and method |
| CN114458422B (en) * | 2022-03-09 | 2022-11-22 | 一汽解放汽车有限公司 | DPF active regeneration control method and system |
| CN114964794B (en) * | 2022-05-09 | 2023-07-14 | 北京理工大学 | Method for rapidly evaluating balance point temperature in endurance process of cDPF device |
| CN114991978B (en) * | 2022-05-25 | 2023-05-16 | 广西科技师范学院 | Fuel-saving management method and system for gasoline engine |
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