KR20050114298A - Method for determinating regeneration of diesel soot filtering device - Google Patents

Abstract

The present invention relates to a method for regenerating a diesel particulate filter, and a method for regenerating a diesel particulate filter implemented by appropriate regeneration logic in consideration of forced regeneration and natural regeneration of the particulate filter in which the accumulation amount of particulates is recorded. It is about.

To this end, the present invention is a flow resistance value (differential pressure difference divided by the exhaust gas flow rate divided by the exhaust gas flow rate of the diesel particulate filter) and the cumulative accumulation of the vehicle for each smoke amount accumulated in the particulate filter regardless of the engine and vehicle conditions, Inputting the mileage and the total volume of the exhaust gas into the ECU; Calculating cumulative mileage and flow resistance value K in the ECU; Forcibly regenerating the diesel particulate filter when the mileage is 200 to 10,000 km; When the flow resistance value (K) is 0.001 to 0.07, there is provided a regeneration method of the diesel particulate filter comprising a step of forcibly regenerating the diesel particulate filter.

Description

Method for determinating regeneration of diesel soot filtering device

The present invention relates to a method for regenerating a diesel particulate filter, and a method for regenerating a diesel particulate filter implemented by appropriate regeneration logic in consideration of forced regeneration and natural regeneration of the particulate filter in which the accumulation amount of particulates is recorded. It is about.

In developing a diesel soot filter, the most important ECU logic depends on "how to use the soot filter continuously." To this end, the soot accumulated in the diesel particulate filter must be continuously burned to prevent the diesel particulate filter from being blocked.

Therefore, it is necessary to continuously increase the temperature of the diesel particulate filter, the post-injection of fuel through the post injection of the engine will be an essential element.

General playback logic conditions can be defined as follows.

1) Engine rpm: 1000 ~ 4000

2) Mileage: 200km

3) Engine load: about 0.7bar

4) Vehicle Speed: 50kph

5) Cooling water temperature: above 50 ℃

Under these conditions, the diesel particulate filter is to be regenerated.

However, the above conditions are arbitrarily regenerating conditions for experiments, and considerations for driving characteristics and mass production are not considered at all.

The above regeneration conditions cannot be applied to diesel vehicles because the regeneration conditions are not the regeneration as a result of understanding the point and condition of the regeneration, but only for the prevention of error. As a result, the regeneration logic by the regeneration condition has no way to block the deterioration of fuel economy and uncontrolled burning, and has a fatal adverse effect on the merchandise of the vehicle.

Currently, in order to manufacture / sales diesel vehicles, many endurance tests and evaluation tests (European evaluation mode: EC mode, US evaluation mode: FTP-75 mode) are required. Actual roads including basic logic, error logic and soot regeneration logic Various development logics should be prepared according to the situation and situation in the company to prevent accidental problems.

In particular, it is, of course, necessary to have sufficient data on the test parameters in all of the above cases.

However, even with sufficient test data, it is necessary to know the exact amount and accumulation of soot in order to make the data useful.

That is, in order to install a diesel particulate filter in a diesel vehicle, a lot of engine data and vehicle data must be secured, and a time period for mapping them is sufficiently required.

Therefore, the key point is to effectively burn the soot collected for the installation of the diesel soot filtration device to enable continuous reuse.

In order to develop / mount the diesel particulate filter, the minimum / priority test variable to be preceded is as follows.

1) Whether the exhaust gas temperature rises due to fuel post-injection

2) Forced Regeneration Strategy Based on Engine Condition

3) Identifying the amount of soot loading and the start and end point of soot regeneration

4) Uncontrolled burning prevention technology.

As mentioned above, building and selling diesel vehicles requires a number of endurance tests and evaluation tests (European evaluation mode: EC mode; US evaluation mode: FTP-75 mode), and basic logic, error logic and soot regeneration. It is necessary to write various development logics according to the conditions and situations in the actual road such as logic to prevent accidental problems.

Therefore, it is needless to say that sufficient data on the test variables in all cases mentioned above are required.

The problem of test variables 1), 2) and 4) should be identified and sufficiently retained the mapping and test data. However, in case of 3), even if sufficient test data is available, The amount and accumulation of soot must be known.

To this end, there is currently no way but to measure the amount of soot accumulated in real vehicles and engines using a scale.

As a result, during actual vehicle and engine testing, to determine the point of forced regeneration of smoke, the amount of soot accumulated in the current soot filter should be removed and re-mounted on the scale, and the test should be carried out by remounting it. do.

However, it is almost impossible to proceed with this process, because the weight of the soot filtration apparatus is generally 12-15 kg and the weight of soot is about 2-12 g. In addition, even when foreign matter is attached to the exterior of the soot filter during driving, the weight of the soot is different, so it is impossible to accurately measure the weight of the soot in real time.

The same is true for the test of the engine object. The engine subject goes through a much easier process in the vehicle, but again it is equally necessary to remove the soot filtration and weigh it on a scale. In other words, the soot filter must be removed and weighed during the test, and it must be refitted to continue the test.

As a result, repeating these tests not only lengthens the development period, but also significantly reduces the reliability of the measured data.

Therefore, it is urgent to set an arbitrary constant value which can know the accumulation amount of smoke in real time in a vehicle, and if this constant value is not set, the accumulation amount of smoke will be unknown.

The constant value may be defined as a flow resistance value (K factor), and the constant value is a constant value which does not change depending on the engine condition, and is a value that varies depending on the diesel particulate filter.

The biggest disadvantage of the prior art is that it is not possible to set the exact regeneration time for the accumulated soot in the apparatus because it does not know the exact amount of soot accumulated in the diesel particulate filter.

As a result, the regeneration point and end point of the diesel particulate filter cannot be known, and there is no information on how much regeneration has been performed, and data on how much regeneration should be performed next.

After all, in order to fully develop the diesel particulate filter, it is necessary to clearly indicate how many g of the particulates are loaded in real time from the vehicle and engine targets.

However, it is currently known that it is impossible to know the loading data for soot, for the following reasons.

1) momentarily changing engine rpm,

2) Before and after pressure of the soot filter, which changes momentarily,

3) the amount of air and fuel that varies from moment to moment,

4) The amount of soot cannot be determined how much it is accumulated.

In view of the above, the present applicant applies a flow resistance value obtained by dividing the pressure difference between the front and rear ends of the diesel particulate filter by the exhaust gas flow rate according to the amount of smoke accumulated in the particulate filter regardless of the engine and vehicle conditions. By measuring and measuring the accumulation level of soot and the corresponding flow measurement data, the diesel can easily determine the forced regeneration point and end point of the soot filtration device by preparing the software basis and measuring the flow measurement value of the actual vehicle later. The method for determining the regeneration time point and end point of the soot filtration device has already been filed (application number: 2004-31211, application date: 2004.05.04).

The previously reported feature measures in advance the flow resistance (differential pressure difference between the diesel particulate filter divided by the exhaust gas flow rate), which varies with the amount of smoke (SL) accumulated in the particulate filter regardless of engine and vehicle conditions. Making a step; Storing each of the particulate matter (SL) and the corresponding flow resistance value (FR1) in advance in a storage / operation means to make data; Determining a flow resistance value FR1 corresponding to the amount of smoke SO stored in advance as a reference for the steel regeneration time (starting point) of the smoke filter; Measuring the flow resistance value FR2 of the actual vehicle and calculating and confirming the soot amount SL corresponding to the measured flow resistance value FR2 in the storage / operation means; The flow resistance value FR2 of the actual vehicle and the corresponding flow resistance value FR1 of the identified soot amount SL are compared / computed by the storage / operation means to determine the forced regeneration time point and the end point of the soot filtration device. And determining the forced regeneration of the particulate filter.

The storage / computing means is an ECU, and compares the flow resistance value FR2 measured in the actual vehicle with the pre-stored flow resistance value FR2, and if the values coincide with each other, determines the forced regeneration time and at the same time the smoke filter. Is forcibly reproduced.

However, although it is true that it is the basis for judging the regeneration time and end point of the diesel particulate filter by the above method, it seems that there will be no problem if judging the regeneration start and end of forced regeneration. The question may be raised if it is detected.

In order to determine this, as a result of the temperature measurement carried out in the diesel vehicle, it can be seen that the inlet temperature of the diesel particulate filter as shown in Figure 3 attached to the 300 ~ 350 ℃ range.

This temperature range is a condition in which the self-ignition of the catalyst coated on the DFP carrier sufficiently occurs in the diesel particulate filter. That is, spontaneous ignition of the soot proceeds on the catalyst CFP, so that the total amount discharged from the engine is not accumulated. As a result, if the driver is in the driving state of a high temperature region such as a highway, the K value is drastically lowered, and the condition that cannot enter the forced regeneration mode is continued, which is shown in FIG.

Referring to FIG. 2, the regeneration mode is performed by forced regeneration at a K value of 0.03 or more. In this case, the forced regeneration mode of the vehicle is never operated before 10,000 km. Then, the question arises whether driving of the vehicle should continue even without the mode of steel regeneration before 1000 km.

Being able to drive 10,000 km without forced regeneration is encouraging for vehicle fuel economy, but we can't guarantee that uncontrolled burning will not occur for 10,000 km.

As a result, no matter how well the logic for forced regeneration, uncontrolled burning may occur without the logic being used once, and there is a problem that a large number of diesel soot filtration devices may occur during forced regeneration.

Therefore, there is a need to properly combine the previously applied forced regeneration logic and the natural regeneration logic according to the CFP catalyst coating.

The present invention has been researched and developed in view of the above, in the forced regeneration of the diesel particulate filter, the natural regeneration condition is found before the detection of the constant value K (Flow resistance), the logic of the forced regeneration Considering that it is difficult to protect CFP, or diesel particulate filter alone, the diesel particulate filter has been developed to achieve proper regeneration logic by matching the value of natural regeneration with the value of K value. The purpose is to provide.

The present invention for achieving the above object is a flow resistance value (divided by the exhaust gas flow rate divided by the front and rear end pressure difference of the diesel particulate filter) and the amount of soot accumulated in the particulate filter regardless of the engine and vehicle conditions and Inputting the accumulated mileage of the vehicle and the total volume of the exhaust gas into the ECU; Calculating cumulative mileage and flow resistance value K in the ECU; Forcibly regenerating the diesel particulate filter when the mileage is 200 to 10,000 km; When the flow resistance value (K) is 0.001 to 0.07, there is provided a regeneration method of the diesel particulate filter comprising a step of forcibly regenerating the diesel particulate filter.

As a preferred embodiment, if the mileage is 1000km or more, the diesel particulate filter is forcibly regenerated, and if the flow resistance value (K) is 0.003 or more, the diesel particulate filter is forcibly regenerated.

In a more preferred embodiment, the primary forced regeneration proceeds at a medium temperature (550-600 ° C.) condition where only a portion of the soot can combust, followed by the secondary forced regeneration in a high temperature range (600-650 ° C., or 650). It is characterized in that the proceeding at).

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

1 is a flowchart illustrating a regeneration method of a diesel particulate filter according to the present invention.

According to the present invention, the forced regeneration of the filtration apparatus is performed by measuring the K value, which is a flow resistance value that varies with the amount of smoke accumulated in the smoke filtration apparatus, and checks the accumulated mileage of the vehicle before the K value is detected in consideration of natural regeneration The main focus is on forced regeneration in two stages.

Referring to the state in which the regeneration of the diesel engine particulate filter according to the invention is made in order as follows.

First, data for forcibly regenerating the soot filtration device is input to the engine ECU, and the flow resistance value K that varies with the amount of soot accumulated in the soot filter device regardless of the engine and vehicle conditions, the cumulative mileage and the discharge of the vehicle The total volume of gas is entered into the ECU.

Subsequently, an operation is performed based on the accumulated mileage and the flow resistance value K inputted from the ECU. When the accumulated mileage is 200 to 10,000 km, preferably 1000 km or more, the diesel particulate filter is forcedly regenerated. .

In the regeneration by the mileage, the flow resistance value K is not detected, and it is determined that the amount of the soot accumulated in the diesel particulate filter is less than the recyclable level. As a result, the mileage of the vehicle should be detected differently for each vehicle, and should be the point where the protection of the fuel efficiency and the soot filtration device is considered appropriate.

At this time, since the accumulation amount of the soot is small, uncontrolled burning of the diesel particulate filter does not occur even if the conditions for forced regeneration are carried out in a region of high temperature (600 to 650 ° C, or 650 ° C or more).

Next, when the flow resistance value K is 0.001 to 0.07, preferably, when the flow resistance value K is 0.03 or more, the diesel particulate filter is forcedly regenerated.

In this case, the K value is a constant that must be expressed differently according to the condition of the vehicle and the condition of the engine, and if the range is limited, the value is expressed as 0.001 to 0.07, and in the case of the mileage in consideration of the loading amount of the catalyst 200 to 10000 km It is limited to the range of.

On the other hand, even if the mileage is less than 200km in the area where the K value is detected, since the detection amount of soot is large and is represented by the K value, when the forced regeneration logic is performed in the high temperature area, uncontrolled burning is performed. Occurs. Therefore, as described above, if the K value is 0.001 to 0.07, preferably 0.03 or more, the diesel particulate filter is forcedly regenerated.

At this time, forcible regeneration is carried out at a medium temperature (550 to 600 ° C.) condition in which only a part of the smoke can be burned instead of burning a large amount of soot at once, and then the second forced regeneration is performed at a high temperature range (600 to 650 ° C., Or 650 ° C. or higher) to allow the regeneration of a complete diesel particulate filter.

As described above, according to the regeneration method of the diesel particulate filter according to the present invention, in the forced regeneration of the diesel particulate filter, a natural regeneration condition is detected before detection of the constant value K (Flow resistance). In consideration of this, the appropriate regeneration logic can be achieved by matching the degree of natural regeneration with the value at which the K value is derived, thereby achieving a complete regeneration of the diesel particulate filter.

In addition, the method of the present invention can be used as a software key (Key) for the forced soot regeneration of the diesel particulate filter, it can be used as a mapping element of the ECU.

1 is a flow chart showing a regeneration method of the diesel particulate filter according to the present invention,

2 is a graph showing an amount of change in K value according to mileage accumulation;

3 is a graph showing the distribution of CFP inlet temperature of a passenger diesel vehicle;

Claims (3)

In the regeneration method of the diesel particulate filter, Regardless of the engine and vehicle conditions, the flow resistance value (the difference in pressure between the front and rear end of the diesel particulate filter divided by the exhaust gas flow rate) that varies with the amount of smoke accumulated in the particulate filter, the cumulative mileage of the vehicle, Inputting the total volume into the ECU; Calculating cumulative mileage and flow resistance value K in the ECU; Forcibly regenerating the diesel particulate filter when the mileage is 200 to 10,000 km; When the flow resistance value (K) is 0.001 to 0.07, the diesel particulate filter filtration regeneration method comprising the step of forcibly regenerating the diesel particulate filter. The diesel particulate filter of claim 1, wherein the diesel particulate filter is forcedly regenerated when the mileage is 1000 km or more, and the diesel particulate filter is forcedly regenerated when the flow resistance value K is 0.003 or more. Regeneration of Soot Filter. The method of claim 1, wherein the first forced regeneration proceeds at a medium temperature (550 ~ 600 ℃) conditions that can burn only a part of the soot, and then the second forced regeneration is a high temperature region (600 ~ 650 ℃, or 650 ℃ Regeneration method of the diesel particulate filter, characterized in that proceeds in the above).