KR20100009749A - Control methode for exhaust gas decreasing device - Google Patents

Abstract

The present invention relates to a method for controlling an exhaust gas reducing device. More particularly, the exhaust gas is efficiently heated by effectively controlling forced regeneration using a soot amount estimation formula suitable for the environment of each vehicle. The present invention relates to a control method of an exhaust gas reducing device capable of preventing overload and increasing exhaust gas reducing efficiency.

The control method of the exhaust gas reducing device according to the present invention is a control method of the exhaust gas reducing device comprising a burner which is formed in the exhaust pipe through which the exhaust gas of the engine flows, and heats the exhaust gas, and a regeneration filter for DPF. The control method of the gas reduction apparatus S100) after the engine is operated, checking the cumulative smoke accumulation time to check the time that the smoke is collected; S200) determining whether the cumulative soot collection time exceeds a first preset time; S210) a forced regenerating step of forcibly regenerating by operating a burner when the cumulative soot collection time exceeds a first set time; S300) an estimated soot amount calculating step of calculating an amount of soot inside a filter when the soot collecting accumulation time is less than or equal to a first predetermined time; S400) determining whether the calculated estimated suit amount exceeds a first set suit amount; S410) a forced regeneration step of forcibly regenerating by operating a burner when the calculated estimated suit amount is greater than a first set suit amount; S420) when the calculated estimated suit amount is less than or equal to a first set suit amount, returning to the accumulated time checking step; And S500) a forced regeneration termination step of stopping the burner and ending the forced regeneration after performing the forced regeneration step; Characterized in that it comprises a.

Description

CONTROL METHOD FOR EXHAUST GAS DECREASING DEVICE}

The present invention relates to a method for controlling an exhaust gas reducing device. More particularly, the exhaust gas is efficiently heated by effectively controlling forced regeneration using a soot amount estimation formula suitable for the environment of each vehicle. The present invention relates to a control method of an exhaust gas reducing device capable of preventing overload and increasing exhaust gas reducing efficiency.

Diesel cars are used in large vehicles because they can reduce fuel consumption compared to conventional gasoline vehicles and have excellent output, and are increasingly applied to small vehicles.

However, the diesel engine is combusted by the fuel injected into the engine to increase the temperature by the compression of the piston causing self ignition, so incomplete combustion occurs due to the inhomogeneous fuel and air in the process, harmful emissions (soot) is generated. do.

In particular, the hazardous emissions are mainly gaseous substances (nitrogen oxides (NOx), hydrocarbons, carbon monoxide) and particulate matter (PM, Particulate Matter), and it is reported that harmful emissions from diesel vehicles account for 40% of the total air pollution. Accordingly, various countries have regulated the emission of exhaust gas and have been disclosed to reduce the exhaust gas is inserted into the exhaust passage in order to satisfy this.

However, the conventional exhaust gas reducing device collects soot by the catalytic filter and oxidizes the collected soot by the catalyst. However, when the liquid fuel is not atomized and vaporized, the engine output is lowered and the fuel is reduced. Due to the very short period of high pressure injection in the combustion chamber, a large amount of harmful particulates are generated, and when there are many low-speed driving sections such as a heavy traffic section, the exhaust gas temperature is low, which makes it difficult to regenerate naturally by the catalyst. . If the catalyst is not functioning properly, the output is lowered due to the increase in exhaust back pressure, the fuel consumption is increased, and if such a phenomenon persists, not only the filter is damaged but also the engine is damaged. In addition, according to the consumption of the engine oil and the use of additives there is a problem that the soot (soot, ash) is accumulated in the particle removal filter unit to bring about the hassle of having to periodically clean the filter.

In order to solve the above problems, a method of combining a natural regeneration method using a catalyst with a forced regeneration method using an electric heater, a burner, and a throttling has been proposed.

The burner for forced regeneration has the advantage of heating the exhaust gas to directly burn the soot to prevent the overload of the filter, and to increase the exhaust gas reduction efficiency by the filter by raising the exhaust gas as a whole, exhaust exhaust flowing through the exhaust pipe The amount of gas inflow, or the temperature is difficult to control the burner, depending on the vehicle driving conditions, and if the operation of the burner is excessive, the filter may be damaged and the durability of the entire apparatus may be lowered. Various methods have been proposed.

For example, Korean Patent Publication No. 2001-0057515 (name of the invention: a method for reducing soot) may be mentioned, which is shown in FIG. 1.

The smoke reduction method illustrated in FIG. 1 includes heating the silencer internal temperature of the diesel vehicle to be a first predetermined temperature; Stopping the heater operation for a first predetermined time; Vehicle driving state determination step (low load / high load-engine speed and engine fuel supply); If the internal temperature of the silencer is lower than the second set temperature in the low load region, the step of heating the heater to the second set temperature is performed and the step of stopping the heater operation after the second set time is performed. When the internal temperature of the muffler is lower than the third set temperature when the state is a high load region, heating the heater to reach a third set temperature and stopping the heater operation after the third set time; It is characterized in that is performed.

The method for reducing smoke is proposed to control the burner operation by varying the set temperature of the burner by determining the driving state of the vehicle, but after heating to a specific set temperature to prevent overheating, the heater is stopped for a specific set time. Regeneration efficiency may be lowered, and simply adjusting the burner set temperature in two stages of low load / high load may not be enough to reflect various vehicle driving conditions, which may waste energy.

In addition, heating the exhaust gas to the target temperature by adjusting the operation time of the burner may increase the catalyst regeneration efficiency to some extent, but there is a limit when the amount of particulate matter generated in the engine is very large. It has been proposed to directly burn the particulate matter by direct injection.

However, the amount of fuel injected directly affects the operation of the burner. However, when the type and amount of the injected fuel are excessively burned, the burned fuel may be incompletely burned and more harmful substances may be discharged. Should be properly controlled.

The present invention has been made to solve the problems described above, the object of the present invention is to estimate the amount of soot contained in the exhaust gas more accurately using the soot amount estimation equation, so that the estimated amount of soot or soot collection time Accordingly, it is possible to efficiently increase the exhaust gas by driving the burner, and to provide a control method of the exhaust gas reducing device that can increase the exhaust gas reduction efficiency by reflecting the state of the individual vehicle and the driving habits of the driver.

The control method of the exhaust gas reducing device according to the present invention is a control method of the exhaust gas reducing device comprising a burner which is formed in the exhaust pipe through which the exhaust gas of the engine flows, and heats the exhaust gas, and a regeneration filter for DPF. The control method of the gas reduction apparatus S100) after the engine is operated, checking the cumulative smoke accumulation time to check the time that the smoke is collected; S200) determining whether the cumulative soot collection time exceeds a first preset time; S210) a forced regenerating step of forcibly regenerating by operating a burner when the cumulative soot collection time exceeds a first set time; S300) an estimated soot amount calculating step of calculating an amount of soot inside a filter when the soot collecting accumulation time is less than or equal to a first predetermined time; S400) determining whether the calculated estimated suit amount exceeds a first set suit amount; S410) a forced regeneration step of forcibly regenerating by operating a burner when the calculated estimated suit amount is greater than a first set suit amount; S420) when the calculated estimated suit amount is less than or equal to a first set suit amount, returning to the accumulated time checking step; And S500) a forced regeneration termination step of stopping the burner and ending the forced regeneration after performing the forced regeneration step; Characterized in that it comprises a.

In addition, between the forced regeneration step and the forced regeneration step, determining whether the forced regeneration time exceeds the second set time in the forced regeneration step; S610) ending the forced playback when the forced playback time exceeds a second predetermined time; And S620) when the forced regeneration time is less than or equal to a second predetermined time, returning to the forced regeneration step; It is characterized in that it is further included.

In addition, the method for reducing the exhaust gas S700) the soot amount estimation equation completion step used in the estimated soot amount calculation step; characterized in that it further comprises, wherein, the soot amount estimation formula is [Equation 1] It is characterized by.

[Equation 1]

In addition, the step of completing the S700) the soot amount estimation formula S710) engine RPM for increasing the engine RPM to a maximum value in a predetermined unit, and changing the idle state and measuring the back pressure and temperature according to each engine RPM, back pressure, and Collecting temperature information; Determining the constants a, b, and c by substituting the respective engine RPM, back pressure, and temperature information into [Equation 1] to obtain constants a, b, and c having the smallest deviation of the estimated suit amount; And S730) determining the proportional constant A by substituting the soot amount in the state where the soot amount is 0 and the forced regeneration start state into [Equation 1] to be a specific estimated suit amount, respectively; Characterized in that it is performed, including.

Further, in the step S300 of calculating the estimated suit amount, the estimated suit amount is repeatedly calculated every first time, and after calculating a plurality of first average values of the calculated estimated values for a second time, the final of the first average values again. Characterized in that determined by the average value.

In addition, S800) characterized in that it further comprises a device status check step to check the device status before the cumulative time check step, the device is characterized in that the means for measuring the engine RPM, back pressure, or temperature.

At this time, the first set time is characterized in that 2 to 12 (hours), the first set suit amount is characterized in that 2 to 10 (g / L), the second set time is 400 to And 600 (seconds).

Accordingly, the control method of the exhaust gas reducing device of the present invention can estimate the amount of soot using vehicle RPM, back pressure, temperature information, can control the operation of the burner according to the amount of soot, and enhance the effect by the burner. By effectively burning particulate matter, it is possible to prevent an overload of the regeneration filter for the DPF and to increase the exhaust gas reduction efficiency.

In addition, the present invention basically operates the apparatus by setting the first set time to 2 to 12 hours, and assists in all vehicles, such as a vehicle in which a large number of suits are generated and a vehicle in which a number of small suits are generated, by using a soot amount estimation formula. It has the advantage of stable device operation.

The control method of the exhaust gas reducing device of the present invention having the features as described above will be described in detail with reference to the accompanying drawings.

2 is a view showing a general exhaust gas reducing device 50, Figure 3 is a schematic diagram of a control method of the exhaust gas reducing device according to the present invention, Figure 4 is a schematic diagram showing the completion step of the soot amount estimation formula according to the present invention. 5 is a diagram illustrating an engine RPM and an estimated suit amount according to a control method of an exhaust gas reducing device of the present invention, and FIG. 6 is an actual suit amount measurement value and an estimated suit according to a control method of an exhaust gas reducing device of the present invention. 7 is another schematic view of the control method of the exhaust gas reducing device according to the present invention, and FIG. 8 is another schematic view of the control method of the exhaust gas reducing device according to the present invention, and FIGS. 9 and 10. Is a view showing the estimated suit amount according to the control method of the exhaust gas reducing device of the present invention, Figure 11 is a view showing the temperature according to the control method of the exhaust gas reducing device of the present invention, Figure 12 It is a figure which shows the back pressure by the control method of the waste gas reduction apparatus of this invention.

The control method of the exhaust gas reducing device of the present invention can be applied to various exhaust gas reducing devices 50 evenly, and the exhaust gas reducing device 50 of a general form will be described first for smooth explanation.

2, a general exhaust gas reducing device 50 is formed in the exhaust pipe 20 generated from the engine 10, the burner 30 for heating the exhaust gas and the DPF regeneration filter for regenerating particulate matter ( 40) are formed sequentially.

An oxidation filter 40 (DOC) may be further provided at the front end of the regeneration filter 40 for the DPF, and the method of controlling the exhaust gas reducing device of the present invention is in addition to the exhaust gas reducing device 50 shown in FIG. The burner 30 may be changed in various forms using a plasma electrode, a spark plug, or a heater.

The control method of the apparatus for reducing exhaust gas according to the present invention includes: S100) a soot collection accumulated time checking step; S200) determining whether the accumulated soot collection time exceeds a first predetermined time; S210, 410) forced regeneration step; 300) calculating an estimated suit amount; S400) determining whether the calculated estimated suit amount exceeds the first set suit amount; S420) returning to the accumulated time checking step; And S500) forced reproduction end step; It includes.

First, the step of checking the cumulative smoke collection time S100 is a step of checking the time when the smoke is collected in the filter by operating the engine 10, the time when the smoke is collected by determining the time when the engine 10 is operated. This step is to check, using the generation time and maintenance time of the engine RPM information can be confirmed.

S200) determining whether the accumulated soot collection time exceeds a first predetermined time; Is a step of determining whether the cumulative soot collecting time determined in the step of checking the soot collecting time exceeds a first predetermined time.

S210) the forced regeneration step is a step of performing forced regeneration by operating the burner 30 when the cumulative soot accumulation time exceeds the first preset time in the determination step, wherein the first preset time is 2 to 12 (hours). Is preferred.

That is, the first predetermined time is a time at which it is necessary to regenerate the filter after the soot is collected in the filter, apart from the accumulated soot amount, such as engine 10 performance, vehicle driving pattern (high speed, low speed), and the like. It is set by the vehicle condition.

If the cumulative soot collection time is less than or equal to the first predetermined time in the determining step, 300) an estimated suit amount calculation step is performed.

300) The estimating suit amount calculating step is a step of estimating an actual accumulated soot amount not determined as time, and the present invention uses a soot amount estimation formula having a value varied according to each vehicle.

The soot amount estimation equation is as shown in Equation 1 below.

[Equation 1]

[Equation 1] is to determine the constant a, b, c and the proportional constant A is not determined to complete the soot amount estimation formula (Equation 1), which is shown in Figure 4, S700) soot amount estimation formula Completion step; Through the 300) estimated soot amount calculation step is determined through, in more detail, the S700) soot amount estimation step completion step S710) engine RPM, back pressure, and temperature information collection step; S720) determining the constants a, b, c; And S730) determining the proportional constant A; It is carried out including.

In step S710, the engine RPM, the back pressure, and the temperature information collecting step are to increase the engine RPM to a maximum value by a predetermined unit, and measure back pressure and temperature according to each engine RPM while changing to an idle state. Collect the back pressure and temperature information while changing the engine RPM in stages as shown in the figure.

In this case, the back pressure or temperature may be measured by using each sensor at a plurality of points.

S720) The constants a, b, and c are determined by substituting the engine RPM, back pressure, and temperature information into [Equation 1] to obtain constants a, b, and c having the smallest deviation of the estimated suit amount.

S730) The proportional constant A determination step is a step of obtaining the proportional constant A by substituting the amount of the soot in the state where the soot amount is 0 and the forced regeneration start state into the equation 1 so as to determine the specific estimated soot amount, respectively.

The estimated suit amount shown in FIG. 5 has the smallest deviation when the a, b, and c changes, and the first set suit in which the estimated suit amount is 8000 and forced regeneration should be started in the absence of soot. 6 shows the estimated suit amount according to the engine RPM after determining the proportional constant A when the estimated suit amount becomes 9000 value at 4 g / l, and compares the estimated suit amount with the actual suit amount in FIG. Referring to the figure, it was confirmed that the soot amount estimation equation (Equation 1) can be used as an equation for estimating the amount of soot since the estimated soot amount and the actually measured soot amount have a high correlation.

That is, the present invention can correct the unsuited soot quantity estimation equation appropriately for each vehicle, so that the deviation according to various vehicle conditions and driver habits can be corrected, so that the soot quantity can be more accurately predicted, and the exhaust gas reduction device ( 50) can be controlled.

After the 300) estimated suit amount calculation step is performed, step S400) determines whether the calculated estimated suit amount exceeds a first set suit amount.

The first set soot amount refers to the amount of soot that is required to be forcibly regenerated because a lot of soot is collected in the actual filter, although the cumulative time for collecting soot in the filter has not reached the set time for which forced regeneration is required.

In this case, since the estimated suit amount is a value which is proportional to the suit amount, not the actual suit amount, the comparison value may be different from each other, so that the first set suit amount is converted to the estimated suit amount or the estimated suit amount is compared. Is determined in accordance with the first set suit amount.

Further, in the 300) estimating suit amount calculation step, the determination of the estimated suit amount is repeatedly calculated every first time, as shown in FIG. 9, and as shown in FIG. 10, during the second time. After calculating a plurality of first average values of the calculated estimated values, the final average values of the first average values are again determined.

In more detail, FIG. 9 illustrates an estimated value initially calculated using the engine RPM, back pressure, and temperature information every second, and FIG. 10 illustrates a moving average of the first calculated estimated value three times in 60 seconds. After calculating one average value (blue), the final estimated suit amount was determined using their average (red) again.

That is, in FIG. 9, the first time is 1 second and the second time is 60 seconds.

In FIG. 9 and FIG. 10, the amount of the estimated suit suddenly decreased, as illustrated in FIG. 11, the burner 30 is operated to reduce the internal soot amount. The operation of the burner 30 is performed by fuel injection or a thermocouple. It can be confirmed by increasing the exhaust gas temperature using.

Accordingly, as shown in FIG. 12, as the regeneration starts, the back pressure may also be lowered from 4.5 (psi) to 3 (psi) or less.

S410) The forced regeneration step is performed when the calculated estimated suit amount is greater than the first set suit amount, and it is determined that the burner operation needs to be large because the collected suit amount is large even though the forced regeneration time point has not been reached. As a step of operating the burner, the same process as the forced regeneration step is performed.

S420) the step of returning to the cumulative time checking step is to return to the initial step of checking the cumulative time when the calculated estimated suit amount is less than or equal to the first set suit amount. The control of the exhaust gas reducing device is made by returning to the initial stage of the process.

At this time, the amount of the first set suit may vary depending on the vehicle state, it is preferably 2 to 10 (g / l).

S500) The forced regeneration step is a step of terminating the forced regeneration by stopping the burner 30 after the forced regeneration step is performed.

In addition, the control method of the exhaust gas reducing device of the present invention is a step for determining the time point to terminate the forced regeneration, as shown in FIG. 7, S600) between the forced regeneration step and the forced regeneration end step, Determining whether the forced regeneration time in the forced regeneration step exceeds a second preset time; May be further performed.

The second set time is a time at which the burner 30 is operated to expect a sufficient temperature increase effect. When the burner 30 is exceeded, a specific portion may be overheated, thereby lowering the durability of the device. In the case of exceeding the second preset time, the step of terminating the forced regeneration is performed, and the step S610) of the forced regeneration is performed in the same process as the step S500) of the forced regeneration described above.

S620) If the forced regeneration time is less than or equal to the second predetermined time, the step of returning to the forced regeneration step is a step in which the operation of the burner 30 is further maintained because a sufficient forced regeneration is not performed.

At this time, the second set time is preferably 400 to 600 (seconds).

In addition, the method for controlling the exhaust gas reducing apparatus according to the present invention may further include a device state checking step of confirming a device state before the cumulative time checking step, as shown in FIG. 8.

(S800) device status check step is to check the state of the exhaust gas reducing device 50 and the device for collecting information for controlling the), the device includes means for measuring the engine RPM, back pressure, or temperature can do.

As described above, the control method of the exhaust gas reducing device according to the present invention is a simple method of confirming the exhaust gas accumulation time, the burner 30 operating time or calculating the estimated suit amount using the engine RPM, back pressure, and temperature information. In this way, there is an advantage that can safely and effectively control the operation of the exhaust gas reducing device 50.

5, 6, and 9 to 12 in the present invention has the engine specifications as shown in Table 1 below, equipped with an exhaust gas reduction device 50 on a city bus using ULSD (light oil less than 50ppm-S) fuel As a result of the test, the configuration of the basic exhaust gas reducing device follows the form shown in FIG.

More specifically, the first set time is 4 (hours), the second set time is 480 (seconds), the first set soot quantity is set to 4 (g / l), and the control method of the exhaust gas reducing device of the present invention. This is the result of performing the steps.

Engine type DE12Ti producer Daewoo Heavy Industries Displacement 11,051 cc Output 280ps / 2,100rpm Torque 115 kgm / 1260 rpm Intake Method TCI Number of cylinders / injection method 6 cylinders / DI

Table 1. Engine specification>

The present invention is not limited to the above-described embodiments, and the scope of application is not limited, and various modifications can be made without departing from the gist of the present invention as claimed in the claims.

1 is a schematic view showing a conventional smoke reduction method.

2 is a view showing a general exhaust gas reducing device.

Figure 3 is a schematic diagram of a control method of the exhaust gas reducing device according to the present invention.

Figure 4 is a schematic diagram showing the completion of the soot amount estimation formula according to the present invention.

5 is a view showing the engine RPM and the estimated suit amount according to the control method of the exhaust gas reducing device of the present invention.

6 is a view showing the actual soot amount measurement value and the estimated soot amount according to the control method of the exhaust gas reducing device of the present invention.

Figure 7 is another schematic view of the control method of the exhaust gas reducing device according to the present invention.

Figure 8 is another schematic view of the control method of the exhaust gas reducing device according to the present invention.

9 and 10 are diagrams showing the estimated suit amount according to the control method of the exhaust gas reducing device of the present invention.

11 is a view showing a temperature according to the control method of the exhaust gas reducing device of the present invention.

12 is a view showing the back pressure according to the control method of the exhaust gas reducing device of the present invention.

** Description of the symbols for the main parts of the drawings **

10: engine

20: exhaust pipe

30: burner

40: DPF Regeneration Filter

50: exhaust gas reduction device

S100 ~ S800: each step of the control method of the exhaust gas reducing device according to the present invention

Claims (11)

In the control method of the exhaust gas reducing device comprising a burner 30 for forming the exhaust pipe 20 through which the exhaust gas of the engine 10 flows and heating the exhaust gas, and a regeneration filter 40 for DPF, The control method of the exhaust gas reducing device is S100) after the engine 10 is operated, checking the cumulative smoke accumulation time to check the time when the smoke is collected; S200) determining whether the cumulative soot collection time exceeds a first preset time; S210) a forced regeneration step of forcibly regenerating by operating the burner 30 when the smoke collection time exceeds the first set time; S300) an estimated soot amount calculating step of calculating an amount of soot inside the filter 40 when the cumulative soot collection time is less than or equal to a first predetermined time; S400) determining whether the calculated estimated suit amount exceeds a first set suit amount; S410) a forced regeneration step of forcibly regenerating by operating the burner 30 when the calculated estimated suit amount is greater than the first set suit amount; S420) when the calculated estimated suit amount is less than or equal to a first set suit amount, returning to the accumulated time checking step; And S500) after the forced regeneration step, the forced regeneration end step of terminating the forced regeneration by stopping the burner (30); Control method of the exhaust gas reducing device comprising a. The method of claim 1, S600) determining whether the forced regeneration time exceeds the second preset time between the forced regeneration step and the forced regeneration step; S610) ending the forced playback when the forced playback time exceeds a second predetermined time; And S620) returning to the forced playback step if the forced playback time is less than or equal to a second predetermined time; The control method of the exhaust gas reducing device further comprises. The method of claim 1, The exhaust gas reduction method S700) the control method of the exhaust gas reducing device further comprises; a soot amount estimation equation completion step used in the estimated soot amount calculation step. The method of claim 3, The method for estimating the amount of soot is the control method of the exhaust gas reducing device, characterized in that [Equation 1] below. [Equation 1]

The method of claim 4, wherein S700) the step of completing the soot amount estimation formula S710) increasing the engine RPM to a maximum value in a predetermined unit, and collecting the engine RPM, back pressure, and temperature information for measuring the back pressure and temperature according to each engine RPM while changing to an idle state; S720) Constant a, b, and c determination steps of substituting the respective engine RPM, back pressure, and temperature information into [Equation 1] to obtain constants a, b, and c having the smallest deviation of the estimated suit amount. ; And S730) determining the proportional constant A by substituting the soot amount in the state where the soot amount is 0 and the forced regeneration start state into [Equation 1] to be a specific estimated soot amount, respectively; Control method of the exhaust gas reduction device, characterized in that performed. The method of claim 4, wherein In the estimating suit amount calculation step, the estimated suit amount is repeatedly calculated every first time, and after calculating a plurality of first average values of the calculated estimated values for a second time period, the final suit values of the first average values are again calculated. Control method of the exhaust gas reduction device, characterized in that determined. The method of claim 1, S800) The control method of the exhaust gas reduction device, characterized in that further comprising a device status check step of checking the device status before the step of confirming the cumulative time. The method of claim 7, wherein The apparatus (50) is a control method of an exhaust gas reducing device, characterized in that the means for measuring the engine RPM, back pressure, or temperature. The method of claim 1, And said first set time is 2 to 12 (hours). The method of claim 1, The control method of the exhaust gas reducing device, characterized in that the first set soot amount is 2 to 10 (g / L). The method of claim 1, And said second set time is 400 to 600 (seconds).

Images