JP2005344711A - Method of regenerating diesel soot filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of regenerating a diesel soot filter for embodying a proper regenerating logic by harmonizing a degree of natural regeneration with a degree of deviating a constant value K when forcibly regenerating the diesel soot filter. <P>SOLUTION: The method of regenerating the diesel soot filter comprises a step of inputting to an ECU a fluid resistance value (a value obtained by dividing a pressure difference between the front and rear ends of the diesel soot filter by the flow amount of exhaust gas) different in the amount of soot residing in the soot filter, the cumulative mileage of a vehicle and the total volume of the exhaust gas independently of the conditions of an engine and the vehicle, a step of calculating the cumulative mileage and the fluid resistance value K with the ECU, a step of performing primary forcible regeneration of the diesel soot filter when the mileage is 200-10,000 km, and a step of performing secondary forcible regeneration of the diesel soot filter when the fluid resistance value K is 0.001-0.07. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a method for regenerating a diesel soot filter device, and the regeneration of a diesel soot filter device embodied in an appropriate regeneration logic in consideration of natural regeneration as well as forced regeneration of a soot filter device in which the amount of accumulated smoke is converted into data. Regarding the method.

  When developing a diesel smoke filter, the most important ECU logic is "how can the smoke filter be used continuously". For this purpose, the accumulated soot in the diesel soot filter must be burned continuously so that the diesel soot filter does not become clogged.

  Therefore, the temperature of the diesel smoke filter must be continuously increased. For this purpose, post-injection of the engine fuel (post-injection post injection) is essential.

General playback logic conditions are defined as follows.
1) Engine rpm: 1000 to 4000
2) Travel distance: 200km
3) Engine load: about 0.7 bar
4) Vehicle speed: 50 kph
5) Cooling water temperature: 50 ° C. or higher The diesel smoke filter is regenerated under the above conditions.

  However, the above conditions are arbitrary regeneration conditions for the experiment, and traveling characteristics and conditions for mass production are not considered at all.

The reason why the above regeneration conditions cannot be applied to a diesel vehicle is that the regeneration is not regeneration after grasping the time and condition of regeneration, but exclusively regeneration for preventing errors.
That is, the regeneration logic based on the above-described regeneration conditions has no way of blocking the deterioration of fuel consumption and uncontrolled burning, and has a fatal adverse effect on the commercial value of the vehicle.

  At present, in order to produce / sell diesel cars, many endurance tests and evaluation tests (European evaluation mode: EC mode, American evaluation mode: FTP-75 mode) must be passed through. Various development logics, such as forced regeneration logic, must be created according to the conditions and conditions on the actual road to prevent sudden problems.

  In particular, it goes without saying that sufficient data for the test variables in all the above cases is necessary.

  However, even if we have sufficient test data, in order to use the data effectively, we need to know the exact amount and accumulation of smoke.

  That is, in order to mount a diesel smoke filter device in a diesel vehicle, it is necessary to secure sufficient engine data and vehicle data, and a sufficient period is required to map them.

  Therefore, there is a demand for how to effectively burn the collected smoke so that it can be used continuously in order to attach the diesel smoke filter device.

In order to develop / install the diesel smoke filter device, the minimum and highest priority items to be preceded are as follows.
1) Exhaust gas temperature rise due to fuel after-injection (including Advance / Retard) 2) Measures of forced soot regeneration by engine conditions 3) Understanding of soot loading (loading) amount and start and end points of soot forced regeneration Grasping 4) Technology for preventing uncontrolled burning.

  As described above, in order to manufacture and sell a diesel vehicle, a lot of durability tests and evaluation tests (European evaluation mode: EC mode, American evaluation mode: FTP-75 mode) must be passed, and the basic logic and errors Various development logics such as logic and smoke forcible regeneration logic should be created according to the actual conditions and conditions on the road so that sudden problems can be prevented.

  For this purpose, it goes without saying that sufficient data for the test variables in all the cases described above is required.

  The problem of the test variables 1), 2), and 4) must be grasped, and sufficient mapping and test data must be retained. In the case of 3), sufficient test data is available. Even if you own a, you must know the exact amount and accumulation of smoke for effective use.

  To that end, there is currently only a method for directly measuring the amount of smoke accumulated in the vehicle and engine using a scale.

  That is, in order to ascertain the time point for forced regeneration of smoke during actual tests on vehicles and engines, separate the soot filtration device to determine how much g of soot has accumulated in the current soot filtration device, weigh it, This must be worn again to proceed with the test.

  However, it is almost impossible to carry out such a process. The reason is that the weight of the smoke filter device is generally 12 to 15 kg, and the weight of smoke is about 2 to 12 g, which is very small. This is because even when foreign matter adheres to the outside of the smoke filter device, the weight of the smoke is different, and it is impossible to accurately measure the weight of the smoke in real time.

  The same applies to the test in the engine. In the case of the engine, the process is extremely easy as compared with the case of the vehicle, but the same is true in that the smoke filter device is removed and the weight is measured with a scale. That is, during the test, the smoke filter must be removed and weighed, and then reattached to continue the test.

  After all, if such a test is repeated, not only will the development period be significantly extended, but the reliability of the measured data will be greatly reduced.

  Accordingly, it is urgent to set an arbitrary constant value that allows the vehicle to check the accumulated amount of smoke in real time. If such a constant value cannot be set, the accumulated amount of smoke will not be known.

  As the constant value, a fluid resistance value (Flow resistance, K Factor) can be used. This constant value is a constant value that does not change depending on engine conditions, but is a value that changes depending on the diesel smoke filter.

  The biggest disadvantage of the prior art is that the exact amount of smoke accumulated in the diesel smoke filter device cannot be grasped, and therefore an accurate regeneration time point for the accumulated smoke in the device cannot be set.

  This makes it impossible to know the regeneration point and end point of the diesel smoke filter, and there is no information that can be used to confirm how much regeneration has been performed, and the data on how much regeneration should be performed next is also unknown. Disappear.

  In other words, in order to develop a complete diesel smoke filter, it is necessary to clearly indicate how many grams of smoke are loaded in real time for vehicles and engines. .

However, it is currently considered that it is impossible to know the loading data for smoke, for the following reasons.
1) Engine rpm that changes instantaneously
2) The pressure at the front and rear ends of the smoke filter that changes instantaneously 3) The amount of air and fuel that changes instantaneously 4) The amount of smoke that cannot be determined how much is accumulated

  In view of the above points, the applicant of the present invention determines the fluid resistance value (the pressure difference between the front and rear ends of the diesel smoke filter device as the exhaust gas) depending on the amount of smoke accumulated in the smoke filter device regardless of the engine and vehicle conditions. (The value divided by the flow rate) is measured, and the accumulated amount of smoke and the measured fluid value are converted into data, so that a software foundation is prepared and the measured fluid value of the actual vehicle is measured later. A method for determining the regeneration point and end point of a diesel soot filtering device that can easily determine the forced regeneration point and end point of the device has already been filed (Korea Patent Application No. 2004-312111 (2004.05.04). )).

  The feature of the present invention is that, regardless of the conditions of the engine and the vehicle, different fluid resistance values for each smoke amount (SL) accumulated in the smoke filter device (the pressure difference between the front and rear ends of the diesel smoke filter device is expressed by the exhaust gas flow rate). A step of preliminarily measuring the divided value FR1); a step of storing each smoke amount (SL) and the fluid resistance value (FR1) in the storage / calculation means in advance and converting the data into data; and a prestored smoke amount (SL) ) Using the fluid resistance value (FR1) corresponding to) as a reference for the forced regeneration time (starting point) of the soot filter; and simultaneously measuring the fluid resistance value (FR2) of the actual vehicle and the measured fluid resistance value ( A step of calculating and confirming the smoke amount (SL) corresponding to FR2) by the storage / calculation means; the fluid resistance value (FR2) of the actual vehicle and the fluid resistance value of the confirmed smoke amount (SL) (FR1) Compared / calculated by warehouse / calculating means, at the same time it determines the end point and the forced regeneration time of the DPF device lies in comprising the step of determining the forced regeneration possibility of the soot-filtering device.

  Further, the storage / calculation means is an ECU, and compares the fluid resistance value (FR2) measured in the actual vehicle with the fluid resistance value (FR1) stored in advance, and if the values coincide, At the same time, the smoke filter device is forcibly regenerated.

  However, the above method is the basis for judging the regeneration point and end point of the diesel soot filter, and it seems that there will be no problem if it is judged to start and end the forced regeneration. Questions are raised about when the points are detected.

  In order to investigate this, as a result of measuring the temperature in a passenger diesel vehicle, it was found that the inflow temperature of the diesel smoke filter device was in the region of 300 to 350 ° C., as shown in FIG.

  This temperature range is a sufficient condition for the autoignition of the catalyst coated on the DFP support in the diesel smoke filter. That is, the spontaneous ignition of soot progresses on the catalyst CFP, and the entire amount of soot discharged from the engine is not accumulated. That is, when the driver is in a driving state in a high temperature region such as an expressway, the K value rapidly decreases, and the condition that the forced regeneration mode cannot be entered continues, as shown in FIG.

  As shown in FIG. 2, the regeneration mode is executed by forced regeneration when the K value is 0.03 or more. At this time, the forced regeneration mode of the vehicle never operates before 10,000 km. Then, before 10000 km, even if there is no forced regeneration mode, a question arises as to whether or not the vehicle should continue to be operated.

  The ability to travel 10,000 km without forced regeneration is a desirable phenomenon in terms of vehicle fuel consumption, but it cannot be stated that uncontrolled burning does not occur during 10,000 km.

  In other words, no matter how much the logic for forced regeneration can be improved, uncontrolled burning may occur as the logic becomes unusable once, and during forced regeneration, the diesel soot filter device may be unreasonable. There is a problem that it takes.

Therefore, it is necessary to appropriately combine forced regeneration logic and natural regeneration logic by CFP catalyst coating.
Korean Patent Application No. 2004-321211

  The present invention has been researched and developed in view of the above points. In forced regeneration of a diesel smoke filter device, natural regeneration conditions have come before the detection of an ordinary value K (fluid resistance). Considering that it is difficult to protect the CFP, that is, the diesel smoke filter device, only with the forced regeneration logic, the appropriate regeneration is performed by harmonizing the degree of natural regeneration and the value from which the K value is derived. The purpose of the present invention is to provide a method for regenerating a diesel smoke filter device that can implement logic.

  In order to achieve the above object, the present invention provides a method for regenerating a diesel smoke filter device, wherein the fluid resistance value varies depending on the amount of smoke accumulated in the smoke filter device regardless of engine and vehicle conditions (diesel smoke filter device). The pressure difference between the front and rear ends of the exhaust gas divided by the exhaust gas flow rate), the cumulative mileage of the vehicle, and the total volume of exhaust gas are input to the ECU; the cumulative mileage and fluid resistance value (K) in the ECU; Calculating the first forced regeneration of the diesel smoke filter when the mileage is 200 to 10000 km; and when the fluid resistance value (K) is 0.001 to 0.07, the diesel And the second forced regeneration of the soot filter.

  When the mileage is 1000 km or more, the diesel smoke filter device is first forcedly regenerated. When the fluid resistance value (K) is 0.003 or more, the diesel smoke filter device is secondarily forcedly regenerated. It is characterized by that.

  The first forced regeneration is performed at a medium temperature (550 to 600 ° C.) so that only a part of the soot can be burned, and then the second forced regeneration is performed in a high temperature region (600 to 650 ° C., Or 650 ° C. or higher).

  According to the method for regenerating a diesel smoke filter device according to the present invention, in the forced regeneration of the diesel smoke filter device, the natural regeneration condition is taken into consideration before detecting the constant value K (flow resistance), and the degree of natural regeneration. A complete regeneration of the diesel smoke filter device can be achieved by implementing an appropriate regeneration logic in harmony with the value to which the K value is derived. Further, the method of the present invention can be used as a software key for forced soot regeneration of a diesel soot filtering device, and can be used as a mapping element of an ECU.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a flowchart illustrating a method for regenerating a diesel soot filtering device according to the present invention.

  In the present invention, the K value of the fluid resistance value that is different for each amount of smoke accumulated in the smoke filter device is measured so that the filter device is forcibly regenerated. The main point is that the accumulated mileage of the vehicle is checked before the forced regeneration is performed in two stages before the vehicle is detected.

  The state in which the diesel engine soot filter device according to the present invention is regenerated will be described in order as follows.

  First, at the stage where data for forced regeneration of the smoke filter device is input to the engine ECU, regardless of the conditions of the engine and the vehicle, different fluid resistance values K for each amount of smoke accumulated in the smoke filter device, The cumulative mileage of the vehicle and the total volume of exhaust gas are input to the ECU.

  Next, the cumulative mileage input to the ECU and the fluid resistance value K are calculated. When the cumulative mileage is 200 to 10,000 km, preferably 1000 km or more, the diesel soot filter device is first-ordered. Force regeneration.

  Such regeneration by mileage is a state in which the fluid resistance value K is not detected, and it is determined that the amount of smoke accumulated in the diesel smoke filter is below a reproducible level. That is, vehicle mileage should be detected on a vehicle-by-vehicle basis and deemed appropriate for fuel economy and protection of the smoke filter device.

  At this time, since the amount of accumulated soot is small, the uncontrolled burning of the diesel smoke filter device is not performed even if the conditions for forced regeneration proceed in a high temperature range (600 to 650 ° C., or higher than 650 ° C.). Does not occur.

  Next, when the fluid resistance value K is 0.001 to 0.07, preferably when the fluid resistance value K is 0.03 or more, the diesel smoke filter device is secondarily forcedly regenerated.

  At this time, the K value is a constant that varies depending on the conditions of the vehicle and the engine, and the range thereof is 0.001 to 0.07. The mileage is 200 to 10,000 km in consideration of the loading amount of the catalyst. Limited to range.

  On the other hand, when the K value is detected, even if the mileage is 200 km or less, because the detected amount of smoke is large and the K value is detected, when forced regeneration logic is performed in a high temperature region, Uncontrolled burning occurs. Therefore, as described above, when the K value is 0.001 to 0.07, preferably 0.03 or more, the diesel smoke filter device is secondarily forcedly regenerated.

  At this time, a large amount of soot is not combusted all at once, but is forcibly regenerated at an intermediate temperature (550 to 600 ° C.) where only a part of the soot can be combusted, and then the second forced regeneration is performed in a high temperature region. (600 to 650 ° C., or 650 ° C. or higher), and complete regeneration of the diesel smoke filter device can be achieved.

It is a flowchart which shows the regeneration method of the diesel smoke filter apparatus by this invention. It is a graph which shows the variation | change_quantity of K value by mileage accumulation. It is a graph which shows the distribution aspect of the CFP inlet temperature of a passenger diesel vehicle.

Claims (3)

In the regeneration method of the diesel smoke filter device,
Regardless of engine and vehicle conditions, different fluid resistance values for each amount of smoke accumulated in the smoke filter (the pressure difference between the front and rear ends of the diesel smoke filter divided by the exhaust gas flow rate) and the cumulative number of vehicles Inputting mileage and total volume of exhaust gas into the ECU;
Calculating cumulative mileage and fluid resistance value (K) in the ECU;
When the mileage is 200 to 10,000 km, the diesel smoke filter device is first forcedly regenerated;
When the fluid resistance value (K) is 0.001 to 0.07, the method further comprises the step of secondarily regenerating the diesel soot filter device.   When the mileage is 1000 km or more, the diesel smoke filter is first forcedly regenerated, and when the fluid resistance value (K) is 0.003 or more, the diesel smoke filter is secondarily regenerated. The method for regenerating a diesel smoke filter device according to claim 1.   The first forced regeneration is performed at a medium temperature (550 to 600 ° C.) so that only a part of the soot can be burned, and then the second forced regeneration is performed in a high temperature region (600 to 650 ° C., Or 650 ° C. or higher). The method for regenerating a diesel smoke filter device according to claim 1.

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