JP2007023870A - Judging method of regeneration time and ending time of diesel smoke filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a judging method of regeneration time and ending time of a diesel smoke filter capable of judging the regeneration time and the ending time of the diesel smoke filter. <P>SOLUTION: The judging method comprises a step to previously measure a flow resistance value changing for every quantity of smoke, a step to previously store each smoke and the flow resistance value into a storage/calculation means for data processing, a step to determine the previously stored flow resistance value equivalent to quantity of smoke as a standard of the forcible regeneration time (starting time) of the smoke filter, a step to measure the flow resistance value of an actual vehicle and confirm the quantity of smoke to meet the measured flow resistance value, and a step to judge the forcible regeneration time and the end time of the smoke filter by comparing/calculating the flow resistance value of the real vehicle with the flow resistance value of the confirmed quantity of smoke. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for judging the regeneration point and end point of a diesel smoke filter, and more specifically, a value obtained by dividing a pressure difference between the front and rear ends of a diesel smoke filter by an exhaust gas flow rate (hereinafter referred to as a flow resistance value). ) Is a method for determining the regeneration point and end point of a diesel soot filter device, in which the amount of accumulated smoke is converted into data and the forced regeneration point and end point of the smoke filter device can be determined.

  Currently, in order to comply with the EURO-IV regulations, the development of diesel smoke filter devices (see Fig. 2) has been spurred, but many system changes are required to satisfy such regulations, and existing Since only the above oxidation catalyst has difficulty in satisfying the above regulations, a new diesel smoke filter is being developed.

  In particular, in the case of a diesel vehicle, a vehicle with a size of 1.7 tons or less is trying to satisfy the EURO-IV regulation without using a diesel smoke filter, but a vehicle with a size of 1.7 tons or more is diesel-powered. EURO-IV regulations cannot be satisfied without the soot filter.

However, a lot of engine data and vehicle data are required to mount a diesel smoke filter device on a diesel vehicle, and a sufficient period is required to map them.
It is also important to effectively burn the collected soot so that it can be reused continuously because it is equipped with a diesel soot filter.

The following are the minimum and preferential considerations for developing and installing the diesel soot filter.
1) Exhaust gas temperature rise due to fuel after-injection (including advance / late) 2) Smoke forced regeneration strategy for each engine condition 3) Smoke loading (loading) amount grasping and smoke forcible regeneration start and end point grasping 4) Uncontrolled burning prevention technology, etc.

As mentioned above, in order to manufacture and sell diesel vehicles, it is necessary to pass several endurance tests and evaluation tests (European evaluation mode: EC mode, US evaluation mode: FTP-75 mode), and basic logic and errors A variety of development logics such as logic and forced smoke regeneration logic must be created according to the conditions and conditions on the actual road to prevent sudden problems.
Needless to say, this requires sufficient data for all of the above problems.

  Regarding the issues 1), 2) and 4), it is necessary to grasp the problem and to have mapping and test data for it. In the case of item 3), it is necessary to ascertain the exact amount of smoke and its accumulation for effective use together with sufficient test data. At present, however, the amount of smoke accumulated in actual vehicles and engines is measured. The fact is that there is only a way to measure with.

Therefore, in the actual vehicle and engine test, in order to grasp the time point for forced regeneration of smoke, measure how many grams of smoke is accumulated in the current smoke filter device, and install it again to proceed with the test. Don't be.
However, since the weight of the smoke filter is generally 12 to 15 kg, the weight of the smoke is as small as about 2 to 12 g, so the measurement accuracy (Accuracy) is low, and the smoke filter when traveling Since the amount of smoke changes even if foreign substances adhere to the outside, it is impossible to accurately measure the amount of smoke in real time.

In the engine test, it is the same problem to separate the smoke filter and measure its weight with a scale. That is, during the test, the corresponding smoke filter device must be disconnected and weighed, and the test must be continued with this attached.
Repeating such a test not only makes the development period very long, but also reduces the reliability of the measured data.
That is, since the accurate amount of smoke accumulated in the diesel smoke filter device cannot be grasped, it is not possible to set an accurate regeneration time point for accumulated smoke in the device.

The regeneration logic of the current diesel smoke filter device is a certain mileage (more than 200km) or more, taking into account variables such as water temperature (above 50 ° C), engine speed (more than 2000rpm), and vehicle speed. Only in the above manner, smoke is regenerated at 600 ° C. using post injection.
However, there is currently no method for accurately grasping the amount of smoke in the diesel smoke filter before regeneration and the amount of smoke after completion of regeneration. In other words, it may not be possible to grasp how much smoke can be removed, and the situation inside the smoke filter device may not be known at all.
Accordingly, waste of fuel for regeneration of the smoke filter device and deterioration of the durability of the equipment are caused.
Japanese Patent Laid-Open No. 7-4226 JP-A-9-264119

  The present invention has been made in consideration of the above points, and the pressure difference between the front and rear ends of the diesel smoke filter is determined according to the amount of smoke accumulated in the smoke filter regardless of the engine and vehicle conditions. The flow resistance value, which is the value divided by the flow rate, is calculated, and the accumulated amount of smoke and the corresponding flow measurement value are converted into data, so that software is provided, and only the flow measurement value of the actual vehicle is measured thereafter. It is another object of the present invention to provide a method for determining the regeneration point and end point of a diesel smoke filter device that can easily determine the forced regeneration point and end point of the smoke filter device.

  In order to achieve the above object, the present invention provides a flow resistance value (differential pressure difference between the front and rear ends of a diesel smoke filter device) that changes depending on the amount of smoke (SL) accumulated in the smoke filter device regardless of engine and vehicle conditions. A value obtained by dividing the exhaust gas flow rate), a step of storing each smoke amount (SL) and a corresponding flow resistance value (FR1) in the storage / calculating means in advance and converting them into data, The flow resistance value (FR1) corresponding to the amount of smoke (SL) is determined as a standard for the forced regeneration time (starting point) of the smoke filter device, and the flow resistance value (FR2) of the actual vehicle is measured and measured. The step of calculating and confirming the smoke amount (SL) corresponding to the flow resistance value (FR2) by the storage / calculation means, the flow resistance value (FR2) of the actual vehicle, and the confirmed smoke amount (SL) Applicable flow resistance value (FR1 Comparison / calculation is made in storing / calculating means, and wherein determining the forced regeneration whether the DPF while determine the end point and the forced regeneration time of the DPF device, in that it consists of.

  The storage / calculation means is an ECU. When the flow resistance value (FR2) measured in the actual vehicle is compared with the previously stored flow resistance value (FR1) and the values match, The determination is made and the soot filtering device is forcibly regenerated.

  According to the method for judging the regeneration time and end point of the diesel smoke filter according to the present invention, after measuring the flow resistance value, which is a value obtained by dividing the pressure difference between the front and rear ends of the diesel smoke filter by the exhaust gas flow rate, the accumulated amount of smoke In addition, the accumulated smoke amount can be easily grasped simply by measuring the flow resistance value of the actual vehicle by converting the corresponding flow measurement value into data, and based on this, the forced regeneration point and end point of the smoke filter device can be known.

  The method of the present invention can also be applied to an operation method for forced soot regeneration of a diesel soot filtering device, and judges an accumulation amount of soot and predicts an engine control method, fuel amount determination and fuel injection timing. It can also be used in methods.

  Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

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

Prior to the description of the present invention, the prior art will be briefly described. The prior art has a problem in that it cannot grasp the accumulated amount of smoke in the diesel smoke filter of the vehicle that changes in real time.
Since the amount of soot cannot be determined, it is not possible to know the regeneration point and end point for controlling the diesel smoke filter, and there is no information on how much it is being regenerated, and there is also data on how much it should be regenerated next. There wasn't.
In other words, although playback is performed even in the prior art, data for grasping the phenomenon and situation cannot be obtained, so that the reproduction state cannot be grasped at all.

Therefore, in order to develop an efficient diesel soot filter device, it is necessary to clearly show how many grams of soot are loaded for vehicles and engines. Don't be.
That is, it is necessary to derive a constant value for estimating the soot accumulated in the soot filter regardless of the engine and vehicle conditions, and this must be indicated by a specific value for each vehicle. This value must be a constant value that is not affected by the exhaust gas temperature rise, the air amount change, the fuel amount change, etc. for regeneration.

The present invention accurately estimates the amount of soot accumulated in the smoke filter device by providing a constant value that does not change according to the conditions and circumstances in the field, and based on this, the forced regeneration interval The main purpose is to set the start and end points.
The method of the present invention will be described below.

First, the flow resistance value (value obtained by dividing the pressure difference between the front and rear ends of the diesel smoke filter by the exhaust gas flow rate) changes for each smoke amount (SL) accumulated in the smoke filter regardless of the engine and vehicle conditions. Is calculated in advance.
The calculation method of the flow resistance value includes a step of receiving a signal from a differential pressure sensor installed at the front and rear ends of the smoke filter device, calculating a pressure difference between the front and rear ends of the smoke filter device, an intake air amount and a fuel The ECU comprises a step of receiving a signal from the quantity sensor by the ECU and measuring the exhaust gas flow rate, and a calculation step of dividing the front-rear pressure difference by the exhaust gas flow rate.

The attached FIG. 3 shows the flow resistance value (Del. P / Volume Flow) in the vehicle, and represents the flow resistance value in the case of accumulation of smoke amount 6 g / L.
As shown in FIG. 3, a sharp shape (M) may be represented by the engine speed (rpm) and other variables, but this is represented by a value (E) filtered through the ECU. It becomes more stable.

  As shown in FIG. 3, the vehicle speed and rpm change instantaneously, and the amount of air and the amount of fuel change instantaneously in response to the application of the transition section, but the flow resistance value tends to be constant. Most of the values are 0.030 to 0.035. That is, when the accumulated amount of smoke in the diesel smoke filter is about 6 g, it can be seen that the flow resistance value is about 0.030 to 0.035 in the test vehicle and does not easily change depending on the external conditions of the vehicle.

  On the other hand, FIG. 4 attached shows the tendency of the flow resistance value in the case of accumulation of 8 g / L of smoke in the vehicle. In the case of accumulation of 8 g of smoke, the flow resistance value is about 0.050 to 0.055. It has become.

Next, each smoke amount (SL) and the corresponding flow resistance value (FR1) measured in advance as described above are stored / calculated in advance in the storage means, that is, ECU, converted into data, and correspond to each smoke amount (SL). The flow resistance value (FR1) to be used is determined as a reference for the forced regeneration time point (start point) of the smoke filter device.
As described above, when the flow resistance value (FR2) of the actual vehicle is measured in a state where the flow resistance value for each amount of smoke is stored in advance in the ECU, it can be understood how much smoke is accumulated in the actual vehicle.

  That is, the flow resistance value (FR2) of the actual vehicle is measured, and the smoke amount (SL) that matches the measured flow resistance value (FR2) is calculated and confirmed by the storage / calculation means.

Next, the flow resistance value (FR2) of the actual vehicle and the corresponding flow resistance value (FR1) of the confirmed smoke amount (SL) are compared / calculated by the storage / calculation means, and the smoke filter device is forced. A regeneration time point and an end point are determined, and whether or not the soot filter is forcibly regenerated is determined.
As a result, the flow resistance value measured under actual vehicle conditions is a value that can be easily obtained through ECU data (previously stored flow resistance value). When this flow resistance value is monitored, the degree of accumulation of soot And the regeneration point and end point of the diesel smoke filter.

That is, the ECU compares the flow resistance value (FR2) measured in the actual vehicle with the previously stored flow resistance value (FR2), and determines that it is the forced regeneration point when the values match, and the soot and smoke The filtration device is forced to regenerate.
Attached FIG. 5 is a graph showing the correlation between the accumulated amount of smoke and the flow resistance value. In order to draw the linear graph of FIG. 5, a smoke filtering device in which the amount of smoke (which is known in advance) is mounted on a vehicle, a flow resistance value is obtained, and this is graphically represented.

When the graph of FIG. 5 is obtained, a smoke filter device with an unknown amount of smoke accumulated in an actual vehicle is mounted, and when the flow resistance value is obtained, the amount of smoke accumulated in the smoke filter device at that time is accurately predicted. can do.
In order to use the flow resistance value more effectively, when the flow resistance value is calculated by filtering by the ECU and multiplied by about 100, it can be expressed easily.

  Therefore, when trying to regenerate the smoke filter device based on 8 g / L shown in FIG. 4, when the flow resistance value of the actual vehicle is measured to 0.050 to 0.055, it corresponds to the measured flow resistance value. If the flow resistance value of the actual vehicle is equal to or higher than the flow resistance value stored in advance through the calculation of the ECU, the ECU performs forced regeneration of the smoke filter device. Will begin.

FIG. 6 (a) shows a change aspect of the flow resistance value in the case of forced regeneration at 6 g / L, and FIG. 6 (b) shows a change aspect of the flow resistance value in the case of forced regeneration at 8 g / L. Show.
Referring to FIG. 6A, in the case of forced regeneration at 6 g / L, it can be seen that most of the accumulated smoke is burned under the forced smoke regeneration condition of about 1200 seconds under the traveling condition of the corresponding vehicle.
Referring to FIG. 6 (b), it can be seen that in the case of forced regeneration at 8 g / L, smoke regeneration for about 800 to 1000 seconds is necessary.

  As shown in FIGS. 6 (a) and 6 (b), it is possible to determine the total time for forced soot regeneration of the soot filter by the soot loading amount. Assuming that the soot loading amount in the soot filtering device is regenerated based on an arbitrary g, the flow resistance value at that time is set as the starting point of forced smoke regeneration of the ECU logic, and through this, the monitoring flow resistance value is greater than the prestored value. It is possible to determine at a glance how long the forced regeneration is necessary and when the forced regeneration is finished.

It is a flowchart explaining the regeneration time and end point judgment method of the diesel smoke filter apparatus by this invention. It is the schematic which shows a diesel smoke filter apparatus. The flow resistance value (Del.P / Volume Flow) in the vehicle in the case of accumulation of smoke amount 6 g / L is shown. The flow resistance value (Del. P / Volume Flow) in the vehicle in the case of accumulation of smoke amount 8g / L is shown. It is a graph which shows the correlation with a soot accumulation amount and a flow resistance value. (A), (b) is a graph which shows the change of the flow resistance value in the case of forced regeneration in 6g / L and 8g / L.

Claims (2)

Regardless of engine and vehicle conditions, the flow resistance value (value obtained by dividing the pressure difference between the front and rear ends of the diesel smoke filter by the exhaust gas flow rate) that changes for each smoke amount (SL) accumulated in the smoke filter is measured in advance. And the stage of
Storing each smoke amount (SL) and the corresponding flow resistance value (FR1) in the storage / calculating means in advance and converting it into data;
A step of determining a flow resistance value (FR1) corresponding to a pre-stored smoke amount (SL) as a reference for a forced regeneration time point (start point) of the smoke filter device;
Measuring the flow resistance value (FR2) of the actual vehicle and calculating and confirming the smoke amount (SL) that matches the measured flow resistance value (FR2) by the storage / calculation means;
The flow resistance value (FR2) of the actual vehicle and the corresponding flow resistance value (FR1) of the confirmed smoke amount (SL) are compared / calculated by the storage / calculation means, Determining an end point and determining whether to force regeneration of the soot filter;
A method for judging the point of regeneration and end point of a diesel smoke filter device, comprising:   The storage / calculation means is an ECU. When the flow resistance value (FR2) measured in the actual vehicle is compared with the previously stored flow resistance value (FR1) and the values match, The method for determining the regeneration time point and end point of the diesel smoke filter device according to claim 1, wherein the smoke filter device is forcibly regenerated while making a determination.

Images