KR20100061160A - Apparatus for finding an alien substance in urea-s.c.r. and control method using the same - Google Patents

Abstract

PURPOSE: A foreign material detecting apparatus for a urea SCR system and a method thereof are provided to enable a controller to determine whether foreign material is included in urea water or not by comparing value measured by a load cell with standard value. CONSTITUTION: A foreign material detecting apparatus for a urea SCR system comprises a housing(2), a load cell(18), and a controller. Urea water(4) is contained in the housing. The load cell is mounted on the housing and measures the load value of the urea water. The controller comprises value measured in the load cell with a standard value. The controller decides whether the foreign material is included in the urea water or not. A level sensor(12), a temperature sensor and a pressure sensor(16) are formed in the foreign material detecting apparatus.

Description

Apparatus for finding an alien substance in Urea-S.C.R. and control method using the same}

The present invention relates to a foreign matter detection apparatus and a control method of the urea SCC system, and more particularly, to a foreign matter detection apparatus and a control method of the urea SCC system that can improve the detection performance.

European (EURO-5) / North American (BIN-8) diesel vehicles, which are tightened in the future, will need to be equipped with efficient NOx reduction aftertreatment. The results of the present research suggest that 'Selective Catalytic Reduction of NOx or' Ammonia (NH3) 'is injected into high-temperature combustion products (exhaust) and reacted with NOx in exhaust on the catalyst to be reduced to nitrogen (N2). SCR of NOx) 'is an efficient device. In particular, the SCR method (hereinafter referred to as Urea-SCR) using urea instead of ammonia is preferred as an alternative considering the difficulty of transporting and storing ammonia and the hazards of unreacted effluents.

1 illustrates the components and layout of a typical Urea-SCR device. Urea solution (Urea Solution = Urea + H2O) is supplied to the injector from the storage tank (Urea Tank) by the supply pump (Supply Pump) is injected. Urea solution exposed to high temperature exhaust gas produces gaseous ammonia (NH3) by chemical reaction:

The ammonia thus produced is mixed with the exhaust for a period of time (exhaust-urea mixing zone) before entering the catalytic reactor (SCR-Reactor), and then reduced to nitrogen (N2) by chemical reaction with NOx in the exhaust in the catalytic reactor. do

For vehicles employing the Urea-SCR method, other solutions other than the prescribed (or standard) urea water (prepared primarily by mixing 32% weight urea with water)-for example, ordinary water or over-dilution / An important part of European and North American strengthening regulations is the provision of a device / logic (OBD) that detects and alerts when foreign substances such as over-concentrated urea water or fuels are replenished with the SCR system.

In the current SCR technology, the reduction efficiency shown in FIG. 1, that is, NOx reduction measured (or calculated) by measuring (or calculating) the concentration of NOx flowing into the SCR reactor ([NOx] in) and the concentration of NOx remaining after the SCR reaction ([NOx] out) The precautionary method of alarming when the efficiency is abnormally excessive is dominant.

This detection method has the following problems.

The NOx abatement efficiency can only be calculated by operating the CS system, so in order to know if the CS system has failed, the CS system must be operated first. In other words, if you do not operate the system can not know whether the failure occurs because it can operate the system despite the failure can cause environmental pollution.

The present invention is to solve the above problems, the present invention is to provide a foreign matter detection apparatus and control method of the urea SCC system with improved detection performance.

In order to achieve the above object, the present invention is a housing in which urea water is accommodated; A load cell mounted to the housing to measure a load value of the urea water; And a control unit comparing the measured value measured in the load cell with a reference value to determine whether the foreign material is included in the urea water.

In addition, it is possible to further include a level sensor for measuring the water level of the urea water, a temperature sensor for measuring the temperature of the urea water and a pressure sensor for measuring the pressure of the urea water.

In particular, the reference value may be calculated using the level sensor, the temperature sensor and the pressure sensor.

The control unit may compare the measured value with the reference value before the urea SRC system is operated or after the operation of the urea SRC system is finished.

In addition, the present invention comprises a first step of calculating a reference value using a level sensor, a temperature sensor, a pressure sensor; A second step of measuring the measured value by the load cell; And a third step of comparing the reference value and the measured value and determining that a failure has occurred in the urea SLC system when the difference is out of a setting range. do.

Furthermore, the first step and the second step may be performed before the SR system is operated or after the operation of the SR system is terminated.

According to the present invention, it is possible to detect whether or not foreign substances are introduced into the urea water tank by mistake or intentionally in the urea SRC system.

In addition, according to the present invention, it is possible to determine whether foreign matter is included before operating the urea SRC system, thereby preventing contamination and failure of the injection system.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

2 is a block diagram of a foreign substance detection apparatus of the urea SCC system according to the present invention. A description with reference to FIG. 2 is as follows.

The foreign material detecting device of the urea SCC system according to the present invention includes a level sensor 12 for measuring the level of urea water, a temperature sensor 14 for measuring the temperature of the urea water, and a pressure for measuring the pressure of the urea water. Sensor 16.

In addition, the detection apparatus includes a load cell 18 to measure the load value of the urea water, that is, the weight. The load cell 18 measures the weight to generate an output voltage value that varies with the weight.

On the other hand, the detection device includes a control unit 30 receives the input value from the level sensor 12, the temperature sensor 14, the pressure sensor 16 and the load cell 18.

In addition, the controller 30 may determine whether the foreign material is included in the urea SLC system to turn on the warning lamp 40. The warning lamp 40 informs the user whether a failure has occurred in the urea SRC system, so that the user can quickly repair the failure.

In particular, the controller 30 preferably stores data about a reference value. Data for reference values include load values based on the urea water level at standard conditions and correction values under specific temperatures and pressures. The reference value may be calculated by multiplying the load value with the correction value.

The calibration method of the reference value is as follows. General urea water is injected into the designed urea water housing, and the relationship with the load cell output value (mV) according to each urea water level in a standard environment (25 ° C., 1 atm) is established. Then, the correction value at the temperature / pressure possible outside the standard environment is dataized to calculate the load cell value at a specific level / temperature / pressure, and various data are collected.

In detail, first, the relationship between the standard element number level (water level) and the load cell output value (mV) is established in the standard environment through the level sensor 12 as shown in the following table. Examples of related data are shown in the table below.

Level of standard element number (level sensor) empty 0.1 0.2 … 0.5 … 0.9 full Load cell output value (mV) 0 0.52 … … … … … …

In addition, taking into account a specific pressure and temperature state other than the standard environment, the correction value according to the temperature and pressure of the state is dataized. Examples of related data are shown in the table below.

Temperature (℃)
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Pressure (bars) -35 -25 -10 0 10 25 50 70 0.60 … … … … … … … … 0.70 … … … … … … … … 0.80 … … … … … … … … 0.90 … … … … … 0.999 … … 1.00 … … … 1.004 1.001 1,000 0.999 0.997

Finally, the final standard load value, that is, the reference value is calculated. In this case, the reference value is calculated by multiplying the load cell output value by the correction value.

The present invention is a system for warning / alarming by comparing foreign matters with standard load values preliminarily calibrated in the number of standard elements, and determining the foreign matter when the difference between the two values exceeds the set range for the determination of suitability. In particular, the setting range is preferably set to the difference of the actual value with respect to the reference value ± 30%.

3 is a view showing a foreign matter detection device of the SRC system according to the present invention. A description with reference to FIG. 3 is as follows.

The foreign matter detection device of the urea SCC system according to the present invention includes a housing 2 in which urea water 4 is accommodated, and the level sensor 12, the temperature sensor 14, and the pressure sensor 16. May be mounted to the housing 2.

The urea water 4 contained in the housing 2 may be transferred to an injection valve (injector or injector) through the operation of the supply pump 6 and injected into the exhaust pipe.

In particular, the load cell 18 may be mounted on the bottom of the housing 2 to operate by a 12V power supply.

4 is a logic diagram of FIG. 3. A description with reference to FIG. 4 is as follows.

First, the load cell 18 detects a load output for the number of elements (actual load value or measured value).

Then, the level sensor 12 measures the water level, that is, the level of the corresponding element number, and calculates the load cell value for the standard element number. Then, the temperature sensor 14 measures the temperature of the urea water, and the final measured value (standard load value) using the correction value calculated by measuring the pressure of the urea water in the pressure sensor 16. To calculate.

The controller 30 may calculate a difference rate between the measured value and the reference value and determine whether the difference rate is out of the setting range.

If the housing 2 is loaded with standard (regular) urea water, the difference rate will be 0 (or calibration deviation level), while the foreign matter (water, fuel, over-dilution / excess urea water, etc.) is contained. In this case, as the inclusion amount increases, the difference rate will also increase.

5 is a control flowchart of a foreign substance detection apparatus of an SRC system according to the present invention. A description with reference to FIG. 5 is as follows.

First, level values of standard urea water and correction value data according to a specific temperature and pressure may be collected and stored in the controller 30 by a manufacturer or a user who configures the urea SRC system.

Then, it is determined whether the current state is before the operation of the urea SRC system or after the operation of the urea SRC system is terminated (S10).

In this case, before the urea SRC system is operated, it may be in a state similar to that before starting cranking (= IG-On) after key-on. That is, before the urea is injected by the urea SRC system.

In addition, after the operation of the urea SRC system may be finished, it may mean an after-run condition, that is, a period of time after the engine is stopped, generally about 10 seconds. That is, it may include a state in which the operation of the urea SRC system is stopped.

When it is determined that the step S10 is satisfied, the water level, temperature, and pressure of the urea water are measured using the level sensor 12, the temperature sensor 14, and the pressure sensor 16. A reference value is calculated based on this data (S12). In this case, data previously stored in the controller 30 may be used.

Then, the measured value is measured by the load cell 18 (S14). In this case, the measured value may mean an electrical output value according to the weight of the urea water, and includes information on the weight of the urea water.

The difference rate between the reference value and the measured value is calculated, and it is determined whether the difference rate is within a setting range (S16). At this time, the setting range is preferably within approximately ± 30%.

In this case, the difference rate may be calculated as a ratio of (difference between the measured value and the reference value) / (measured value).

If it is determined that the set range is exceeded, the warning light is turned on (S18) and the operation of the CS system may be stopped, or the operation of the CS system may be disabled again. On the other hand, the user can recognize that a failure has occurred in the Urea RS system when the warning light is turned on.

The present invention is not limited to the above-described embodiments, and as can be seen in the appended claims, modifications can be made by those skilled in the art to which the invention pertains, and such modifications are within the scope of the present invention.

1 illustrates components and layout of a Urea-SCR device according to the prior art.

Figure 2 is a block diagram of the foreign matter detection apparatus of the urea SCC system according to the present invention.

3 is a view showing a foreign matter detection device of the urea SCC system according to the present invention.

4 is a logic diagram of FIG. 3.

5 is a control flowchart of a foreign substance detection device of the urea SCC system according to the present invention.

<Description of Signs for Main Parts of Drawings>

2: housing 4: number of elements

12: level sensor 14: temperature sensor

16: pressure sensor 18: load cell

40: warning light

Claims (6)

A housing accommodating urea water; A load cell mounted to the housing to measure a load value of the urea water; And And a control unit comparing the measured value measured by the load cell with a reference value to determine whether the foreign material is included in the urea water. The method of claim 1, A level sensor for measuring the water level of the urea water, A temperature sensor for measuring the temperature of the urea water; The foreign material detection device of the urea SCC system further comprising a pressure sensor for measuring the pressure of the urea water. The method of claim 2, And the reference value is calculated using the level sensor, the temperature sensor, and the pressure sensor. The method of claim 1, The control unit is a foreign material detection device of the urea SAL system, characterized in that for comparing the measured value and the reference value before the operation of the urea SRC system or after the operation of the urea SLC system. Calculating a reference value using a level sensor, a temperature sensor, and a pressure sensor; A second step of measuring the measured value by the load cell; And And comparing the reference value with the measured value and determining that a failure has occurred in the urea SLC system when the difference is out of a predetermined range. The method of claim 5, The first step and the second step is a control method of the foreign material detection apparatus of the urea SCC system, characterized in that is carried out before the SRC system is operated or after the operation of the SRC system is terminated.

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