KR102249936B1 - Monitoring Method of Nitrogen Oxide Exhaust Gas Using Universal Nitrogen Oxide Sensor - Google Patents

Abstract

The present invention relates to a nitrogen oxide emission gas monitoring method using a general-purpose nitrogen oxide sensor. The present invention may include the step of deriving the exhaust gas flow rate in the SEMS, the step of deriving the final discharged nitrogen oxide emission using the derived exhaust gas flow rate and the nitrogen oxide emission concentration measured through the sensor.

Description

Monitoring Method of Nitrogen Oxide Exhaust Gas Using Universal Nitrogen Oxide Sensor}

The present invention relates to a method for monitoring nitrogen oxide emission gas by applying a general-purpose nitrogen oxide (NOx) sensor, and more particularly, an emission flow rate and nitrogen obtained by calculating the intake air flow rate and fuel consumption obtained in the SEMS (Sensor Based Emission Measurement System). It relates to an emission gas monitoring method comprising the step of deriving nitrogen oxide emission (g/s) using the density value of the oxide emission gas and the nitrogen oxide emission concentration (ppm) measured through a sensor.

The exhaust gas of passenger cars and commercial vehicles causes a lot of environmental burden. By introducing limit value regulations to limit emissions, vehicle manufacturers have been compelled to reduce the emissions of individual vehicles, for example through the development of engines and exhaust gas systems, and are now compelled to reduce them. .

The deterioration of the exhaust gas condition during the life of the vehicle, mainly due to the gradual increase in exhaust gas emission due to aging in the drive system and exhaust gas reduction system, but also partially through defective elements, is the reason why the above limit value regulations are not observed. May be.

Efforts to ensure emission levels comparable to the original condition are generally made through regular exhaust gas surveys. The downside to this is that only the next exhaust gas survey is the fault found, and until then, a lot of emissions are made.

If the catalytic converter has not yet reached its operating temperature, it is very low that during the first few seconds of vehicle operation the harmful substances of this exhaust gas are reduced through the catalytic converter. Since the engine makes about 70% of its total emissions in the cold start phase, optimizing the reduction of hazardous substances is valuable at this stage, that is, at this very stage in which no exhaust gas investigation is done at all.

A new starting point for reducing the emissions of this hazardous substance is this "On-Board-Diagnose" (OBD). This refers to a system for controlling exhaust gas by monitoring the faithful functions of individual members related to exhaust gas of a passenger car or a commercial vehicle through sensors. In the United States, long ago there was already the first form of OBD for passenger cars (OBD I-law), which has been phased out from the 1995 model through extensive OBD II-law. While this OBD I focuses solely on controlling the faithful functions of the components related to electronic engine control, the OBD II requires monitoring of all components related to exhaust gas emissions. The emphasis is on monitoring the catalytic converter, lambda-probe, fuel system, secondary ventilation system, exhaust gas return, tank ventilation and detection of combustion failures. When a fault or malfunction of the device is identified, a signal lamp lights up in the instrument cluster and an error code is stored. Since the identified error function is localized and recorded as accurately as possible and the information is stored, it is read by a standardized interface for quick identification by the repair center and repair of the error.

[Patent Document 1] Korean Patent Registration No. 10-1518968. 2015.05.04.Registration.

The present invention was created to solve the above-described problem, and the exhaust flow obtained by calculating the intake air flow rate and fuel consumption obtained in SEMS, the density value of the nitrogen oxide emission gas, and the nitrogen oxide emission concentration (ppm) measured through a sensor. It is an object of the present invention to provide an exhaust gas monitoring method characterized in that the nitrogen oxide emissions (g/s) are derived by using.

The objects of the present invention are not limited to the objects mentioned above, and other objects that are not mentioned will be clearly understood from the following description.

In order to achieve the above objects, a nitrogen oxide emission gas monitoring method using a general-purpose nitrogen oxide sensor according to an embodiment of the present invention is disclosed. The nitrogen oxide emission gas monitoring method includes the steps of deriving the exhaust gas flow rate in the SEMS and deriving the final discharged nitrogen oxide emission using the derived exhaust gas flow rate and the nitrogen oxide emission concentration measured through the sensor. I can.

In addition, according to an embodiment of the present invention, the step of deriving the exhaust gas flow rate in the SEMS may be a step of deriving the exhaust gas flow rate using the intake gas flow rate and the fuel consumption measured by the OBD during driving.

In addition, according to an embodiment of the present invention, the nitrogen oxide emission concentration may be measured in ppm by attaching a nitrogen oxide sensor to the front or rear end of the vehicle post-treatment device in the SEMS.

In addition, according to an embodiment of the present invention, the step of deriving the final discharged nitrogen oxide emission is performed by using the derived exhaust gas flow rate and the nitrogen oxide emission concentration (ppm) and molecular weight ratio measured through the sensor. g/s), and the molecular weight ratio may be a ratio of the specific gas molecular weight to the total exhaust gas molecular weight.

In addition, according to an embodiment of the present invention, the step of deriving the final discharged nitrogen oxide emission is performed by using the derived exhaust gas flow rate, the nitrogen oxide emission concentration (ppm) measured through the sensor, and the density value of the specific gas. It may be a step of deriving oxide emissions (g/s).

Detailed matters for achieving the above objects will become apparent with reference to embodiments to be described later in detail together with the accompanying drawings.

However, the present invention is not limited to the embodiments disclosed below, and may be configured in various different forms, so that the disclosure of the present invention is complete and those of ordinary skill in the technical field to which the present invention pertains ( Hereinafter, it is provided in order to completely inform the scope of the invention to the "normal engineer").

According to an embodiment of the present invention, by estimating the exhaust gas flow rate in SEMS, nitrogen oxide emission measured through a sensor roll using the estimated exhaust gas flow rate, the density value of the diesel exhaust gas, and the density value of the nitrogen oxide exhaust gas. It is possible to provide a nitrogen oxide emission gas monitoring method applying a general-purpose nitrogen oxide sensor that derives the concentration (ppm) as the nitrogen oxide emission (g/s).

The exhaust gas monitoring method of the present invention measures the exhaust gas flow rate in SEMS, which is relatively easy to measure, and determines the nitrogen oxide emission concentration (ppm) using the measured exhaust flow rate and the density value of each exhaust gas, which are features of the present invention. It is possible to derive more accurate exhaust gas by estimating the emission of nitrogen oxides (g/s).

The effects of the present invention are not limited to the above-described effects, and the potential effects expected by the technical features of the present invention will be clearly understood from the following description.

Some of the embodiments are shown in the accompanying drawings so that the features of the present disclosure mentioned above may be understood in detail, in a more detailed description, with reference to the following embodiments. In addition, like reference numbers in the drawings are intended to refer to the same or similar functions over several aspects. However, it should be noted that the accompanying drawings show only specific exemplary embodiments of the present invention, and are not considered to limit the scope of the present invention, and other embodiments having the same effect may be sufficiently recognized. Do it.
1 is a view showing a flow chart of a nitrogen oxide emission monitoring method using a general-purpose nitrogen oxide sensor according to an embodiment of the present invention.
2 is a view showing a comparison of the nitrogen oxide emission concentration (ppm) measured by SEMS and a mobile exhaust gas measurement equipment (PEMS) according to an embodiment of the present invention.
3 is a view showing a comparison of the discharge flow rate (kg / h) measured by the SEMS and the mobile exhaust gas measurement equipment (PEMS) according to an embodiment of the present invention.
FIG. 4 is a view showing a comparison of nitrogen oxide emissions (g/s) measured by SEMS and a mobile exhaust gas measurement equipment (PEMS) according to an embodiment of the present invention.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail.

Various features of the invention disclosed in the claims may be better understood in view of the drawings and detailed description. The apparatus, method, preparation method, and various embodiments disclosed in the specification are provided for illustration purposes. The disclosed structural and functional features are intended to enable a person skilled in the art to specifically implement various embodiments, and are not intended to limit the scope of the invention. The disclosed terms and sentences are intended to describe various features of the disclosed invention in an easy to understand manner, and are not intended to limit the scope of the invention.

In describing the present invention, when it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Hereinafter, a method for monitoring nitrogen oxide emissions using a general-purpose nitrogen oxide sensor according to an embodiment of the present invention will be described.

1 is a view showing a flow chart of a nitrogen oxide emission gas monitoring method using a general-purpose nitrogen oxide sensor according to an embodiment of the present invention.

Referring to Figure 1, the nitrogen oxide emission gas monitoring method applying a general-purpose nitrogen oxide sensor according to an embodiment of the present invention is the step of deriving the exhaust gas flow rate in the SEMS (sensor based emission measurement system) (S101), the derived It may include a step (S103) of deriving the final discharged nitrogen oxide emissions using the exhaust gas flow rate and the nitrogen oxide emission concentration measured through the sensor.

More specifically, the step of deriving the emission gas flow rate in the sensor based emissions measurement system (SEMS) is to calculate the intake gas flow rate (g/s) and fuel consumption (L/h) measured by on-board diagnostics (OBD) while driving. It can be used to derive the exhaust gas flow rate (g/s). Since the exhaust gas flow rate has the same amount as the intake gas flow rate, the exhaust gas flow rate can be derived by obtaining the intake gas flow rate. The intake gas flow rate can be derived using the intake gas flow rate and fuel consumption measured by the OBD while driving.

For example, the intake gas flow rate is equal to the sum of the intake gas flow rate and the fuel consumption. Since the intake gas flow rate is the same as the exhaust gas flow rate, the sum of the intake gas flow rate and the fuel consumption amount is the same as the exhaust gas flow rate. The above example is only an example for describing the present disclosure, and the present disclosure is not limited thereto.

In addition, it may include a step (S103) of deriving the final discharged nitrogen oxide discharge using the derived discharge gas flow rate and the nitrogen oxide discharge concentration measured through the sensor.

More specifically, the step (S103) of deriving the flow rate for each final discharged gas is from a mass point of view using the derived exhaust gas flow rate (g/s), the nitrogen oxide emission concentration (ppm) and the molecular weight ratio measured through the sensor. It may be a step of deriving the amount of nitrogen oxide emissions. The molecular weight ratio may be a ratio of the molecular weight of a specific gas to the total exhaust gas molecular weight. The final discharged gas flow rate can be derived by multiplying the volume fraction (ppm), mass discharge flow rate (g/s), and molecular weight ratio (ratio of the molecular weight of a specific gas to the total discharged gas molecular weight).

The nitrogen oxide emission (W _NOx ) is based on the exhaust gas mass flow rate (G _exh ), the nitrogen oxide emission gas molecular weight (M _NOx ), the exhaust gas molecular weight (M _exh ), and the nitrogen oxide emission concentration (C _NOx ) measured through a sensor. It can be derived by doing. The nitrogen oxide emission (W _NOx ) may have the following formula.

For example, since M _NOx is 46 (g/mol) and M _exh is 28.9 (g/mol) (Diesel), W _NOx can be obtained by substituting _{G exh and} C _NOx derived in the above step into the above equation. . The above example is only an example for describing the present disclosure, and the present disclosure is not limited thereto.

In addition, the step of deriving the flow rate for each gas discharged (S103) includes the derived discharge flow rate (L/s), the nitrogen oxide emission concentration (ppm) measured through the sensor, and the density value (g/L) of the specific gas. It may be a step of deriving nitrogen oxide emissions from a volume perspective. The final discharged gas flow rate can be derived by multiplying the volume fraction (ppm), the volume discharge flow rate (L/s), and the density (g/L). The nitrogen oxide emission (W _NOx ) (g/s) is the specific gas density value (ρ _gas ) (g/L), the exhaust gas volume flow rate (Q _exh ) (L/s), and the nitrogen oxide emission concentration measured by the sensor. It can be derived using (W _{NOx )(ppm).} The nitrogen oxide emission (W _NOx ) (g/s) may have the following formula.

For example, under certain conditions _{, ρ exh} . _Diesel is 1.2943 (kg/m ³ ), ρ exh. _{Since Petrol} is 1.2941 (kg/m ³ ) and ρ _NOx is 2.053 (kg/m ³ ), W _NOx can be obtained by substituting _{C NOx and} Q _exh derived in the above step into the above equation. The above example is only an example for describing the present disclosure, and the present disclosure is not limited thereto.

2 is a view showing a comparison of the nitrogen oxide emission concentration (ppm) measured by the SEMS and the mobile exhaust gas measuring equipment (PEMS) according to an embodiment of the present invention, Figure 3 is a diagram according to an embodiment of the present invention It is a diagram showing a comparison of the discharged flow rate (kg/h) measured by SEMS and the mobile exhaust gas measurement equipment (PEMS), and FIG. 4 is a view showing the comparison of the SEMS and the mobile exhaust gas measurement equipment (PEMS) according to an embodiment of the present invention. It is a diagram showing a comparison of the measured nitrogen oxide emissions (g/s).

More specifically, FIG. 2 is a graph showing a time series diagram comparing the nitrogen oxide (NOx) emission concentration (ppm) obtained from SEMS and the nitrogen oxide (NOx) emission concentration (ppm) obtained from PEMS, and FIG. It is a graph showing a time series diagram comparing the discharge flow rate (kg/h) calculated by summing the fuel consumption and the intake air amount obtained from OBD and the discharge flow rate (kg/h) measured by the flow meter of PEMS. After deriving the nitrogen oxide (NOx) emission concentration (ppm) obtained from SEMS as the emission (g/s) using the discharge flow rate (kg/h) obtained from the flow meter, the NOx emission (g/s) obtained from the PEMS equipment It is a graph showing a time series plot compared to.

2 to 4, data of the emission concentration (ppm) obtained from SEMS and the discharge flow rate (kg/h) calculated from the intake air flow rate and fuel consumption obtained from the vehicle's OBD are obtained from the flow meter of PEMS, respectively. As a graph showing the comparison, the nitrogen oxide (NOx) emission concentration (ppm) measured by the PEMS equipment and the general-purpose nitrogen oxide is shown as a time series, and the nitrogen oxide (NOx) emission concentration obtained from the general-purpose nitrogen oxide sensor is nitrogen obtained from the PEMS equipment. When compared with the concentration of oxide (NOx) emission, it can be seen that the correlation is high.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art will be able to make various changes and modifications without departing from the essential characteristics of the present invention.

Accordingly, the embodiments disclosed in the present specification are not intended to limit the technical idea of the present invention, but are intended to be described, and the scope of the present invention is not limited by these embodiments.

The scope of protection of the present invention should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be understood as being included in the scope of the present invention.

Claims (5)

Deriving an exhaust gas flow rate in a sensor based emission measurement system (SEMS); And
Using the derived exhaust gas flow rate (g/s) and the nitrogen oxide emission concentration (ppm) measured through a sensor attached to the front or rear end of the vehicle's post-treatment station within the SEMS, the final emission of nitrogen oxides is derived. Including the step of,
The step of deriving the exhaust gas flow rate in the SEMS,
This is a step of deriving the exhaust gas flow rate (g/s) using the intake gas flow rate (g/s) and the fuel consumption (L/h) measured by OBD (on-board diagnostics) while driving,
The step of deriving the final discharged nitrogen oxide emissions,
It is a step of deriving nitrogen oxide emission (g/s) using the derived exhaust gas flow rate (g/s) and the nitrogen oxide emission concentration (ppm) and molecular weight ratio measured through the attached sensor, and the molecular weight ratio Is the ratio of the specific gas molecular weight to the total exhaust gas molecular weight,
Using the following equation to derive nitrogen oxide emissions,
A method for monitoring nitrogen oxide emissions using a general-purpose nitrogen oxide sensor.

here,

Is the nitrogen oxide emissions,

Is the mass flow rate of the exhaust gas,

Is the molecular weight of the nitrogen oxide emission gas,

Is the molecular weight of the exhaust gas,

Denotes the nitrogen oxide emission concentration measured by a sensor attached to the front or rear end of the vehicle's post-treatment station in SEMS.
delete delete delete The method of claim 1,
The step of deriving the final discharged nitrogen oxide emissions,
It is a step of deriving nitrogen oxide emissions (g/s) using the derived exhaust gas flow rate, the nitrogen oxide emission concentration (ppm) measured through a sensor, and a density value of a specific gas,
Using the following equation to derive nitrogen oxide emissions,
A method for monitoring nitrogen oxide emissions using a general-purpose nitrogen oxide sensor.

here,

Is the nitrogen oxide emissions,

Is the volume flow of the exhaust gas

Is the nitrogen oxide density value,

Is the volume flow rate of the exhaust gas,

Denotes the nitrogen oxide emission concentration measured by a sensor attached to the front or rear end of the vehicle's post-treatment station in SEMS.

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