KR101437105B1 - Test method for spray cone-angle of injector - Google Patents

Abstract

Disclosed is an injector spray angle measurement method. The injector spray angle measurement method according to the present invention includes: an image processing step for processing a spray image; and a step for measuring a spray angle from information on a spray reach distance which is a distance to a point where the spray image processed through the image processing step reaches the farthest from an injector nozzle tip. According to the injector spray angle measurement method of the present invention, the spray angle can be measured from the information on the distance reached by the spray image and a spray behavior can be predicted. Accordingly, a measurement result can be more accurate and stable than in the related art even after a predetermined spray development as well as initial spray. Therefore, a research on engine efficiency improvement such as engine injection amount and injection time can be facilitated by actual injector spray behavior information.

Description

[0001] The present invention relates to a method for measuring a spray angle of an injector,

The present invention relates to a spray angle measurement method of an injector, and more particularly, to a spray angle measurement method of an injector for evaluating a spray angle of a fuel injector from information on a maximum reaching distance of a spray image.

Generally, an internal combustion engine is provided with a fuel injection nozzle (or an injector, hereinafter referred to as an injector) for injecting fuel into a cylinder inside the engine. The injector is provided as a rod-like structure and connected to one side of the engine. The injector injects the fuel into the cylinder at an appropriate time and in an appropriate amount through a device such as a filter and a valve. Actually, most of the injectors currently used are electronic control systems, and solenoid valves are installed therein. The solenoid valves are opened and closed according to electric signals transmitted from the control unit or ECU of the vehicle.

Such an injector is required to measure the spray angle or the spray angle when spraying fuel into the cylinder. Here, the spray angle refers to the angle of the spray formed by the sprayed liquid when a liquid substance such as fuel is sprayed from the nozzle. If the spray angle of the injector does not match the shape of the engine combustion chamber or the speed of the engine, the fuel may collide against the wall surface of the combustion chamber to cause excessive smoke generation, or the amount of wear of the cylinder may increase and the durability of the engine may be significantly reduced. The spray angle of the injector is becoming more important in the field of diesel engine injecting fuel directly into the cylinder or gasoline engine of the direct injection type which has been studied recently.

Usually, the spray angle is measured by analyzing the macroscopic behavior of the spray through a visualization experiment of visualizing the spray, etc. In this case, it is necessary to acquire a plurality of spray images at a short time interval, Can be measured. In the conventional spray angle measurement method, the outermost point in the radial direction from the nozzle tip is respectively found in the photographed spray image, and the angle between the two points and the nozzle tip is defined as the spray angle .

However, the conventional spray angle measuring method can measure the spray angle relatively accurately at the initial stage of spraying, but after the spray develops to a certain level or more, the measured spray angle is significantly increased compared to the actual spray angle There is a problem that the spraying behavior of the actual injector can not be accurately reflected. This is because a plurality of spray images are photographed using a high-speed camera or the like, and thus the outermost points measured for each image in the image processing process are different from each other, and the outermost points are dispersed in a large range.

A related art is disclosed in Japanese Patent Application Laid-Open No. 10-2002-0050640 (entitled: Fuel nozzle spray angle measuring device, published on Jun. 27, 2002).

SUMMARY OF THE INVENTION It is an object of the present invention to improve the efficiency of the engine such as the amount of fuel injected or the injection timing through the actual spraying behavior information of the actual injector even after the initial development of the spray, The present invention provides a method of measuring the spray angle of an injector,

According to an aspect of the present invention, there is provided a method for measuring a spray angle of an injector, including: an image processing step of processing a spray image; And measuring a spray angle from information on the spray reach distance from the nozzle tip of the injector to the point farthest from the spray image in the spray image processed through the image processing step.

The method may further include photographing the spray image from a spray jetted from a nozzle tip of the injector prior to the image processing step.

Wherein the image processing step comprises: removing the reflected light of the nozzle tip and the non-spray-related portion in the spray image; And converting the spray image to black and white to store the distribution of the spray.

In the step of storing the distribution of the spray, the portion where the spray is obtained may be converted into a white pixel, and the portion where the spray is not obtained may be converted into a black pixel.

Wherein the measuring the spray angle comprises: calculating the spray reach distance; Calculating a counting reference distance corresponding to a preset ratio in the spray reach distance, forming a virtual arc having a radius of the counting reference distance from the nozzle tip, and counting the number of white pixels existing within the arc; Calculating an area of the sector from the counted number of white pixels; And calculating a spray angle from a relationship between the width of the sector and the virtual circle width formed by the arc.

The spray reach may be a length from the nozzle tip to the white pixel located farthest from the nozzle tip.

The spray angle can be calculated from a relation of the width of the sector / imaginary circle width * 360 formed by the arc.

The present invention proposes a measurement standard for measuring the spray angle from information on the reach distance of the sprayed image, so that stable and accurate measurement results can be obtained even after the spray has developed to a certain level or more, It is possible to more easily study the efficiency improvement of the engine such as the fuel injection amount and injection timing through the actual sprayer behavior information of the injector.

1 is a schematic block diagram for explaining a configuration of a spray angle measuring method of an injector according to an embodiment of the present invention.
Fig. 2 is a block diagram for explaining the configuration of the spray angle measuring unit in Fig. 1. Fig.
3 is a view showing an example of a spray image measured using the high-speed camera of FIG.
Fig. 4 is an enlarged view of the area B in Fig. 3 (c).
5 is a flowchart of a method of measuring the spray angle of an injector according to an embodiment of the present invention.
6 is a flow chart illustrating spray image processing steps in FIG.
7 is a flow chart for explaining the spray angle measurement step in FIG.
FIG. 8 is a view showing a measurement result of the spray angle obtained by the conventional spray angle measurement result and the spray angle measurement method of the injector according to the embodiment of the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in order to avoid unnecessary obscuration of the present invention.

In the conventional spray angle measurement method, an angle formed between two points and a nozzle tip is calculated by finding both outermost points on both sides from the center of the spray. At this time, a radial line connecting the nozzle tip and the pixels constituting the farthest spray in the circumferential direction is set, and the angle formed by this line is calculated and stored as the spray angle.

In the conventional spray angle measurement method, the spray angle can be measured relatively accurately at the initial stage of spraying. However, since the spray angle measured after the spray development exceeds a certain level is significantly increased compared to the actual spray angle, There is a problem that the spray behavior can not be accurately reflected.

The method of measuring the spray angle of the injector according to the embodiment of the present invention proposes a method of measuring the spray angle of the injector 2 using the counting reference distance r derived from the information on the spray reach distance R .

FIG. 1 is a schematic block diagram for explaining a configuration of a spray angle measuring method of an injector according to an embodiment of the present invention. FIG. 2 is a block diagram for explaining a configuration of a spray angle measuring unit in FIG. 1, FIG. 5 is a flow chart of a method of measuring the spray angle of an injector according to an embodiment of the present invention, and FIG. 6 is a flow chart illustrating a spray image processing step in FIG. 5 FIG. 7 is a flow chart for explaining the spray angle measuring step in FIG. 5, FIG. 8 is a graph showing the spray angle measurement result obtained by the conventional spray angle measurement method and the injector spray angle measuring method according to an embodiment of the present invention Fig.

A method for measuring the spray angle of an injector according to an embodiment of the present invention includes a step S110 of photographing the spray image from a spray jetted from a nozzle tip 3 of the injector 2 (S110), an image processing step Measuring a spray angle from information on a spray arrival distance (R) from the nozzle tip (3) of the injector (2) to the point where the spray image processed through the image processing step reaches the farthest from the nozzle tip (3) (S130).

First, as shown in Fig. 5, a step of photographing a spray image from the spray jetted from the nozzle tip 3 of the injector 2 may be performed (S110). The spray image may be photographed by at least one photographing means shown in FIG. 1. The photographing means used at this time may be a high-speed camera 4, or a camera having excellent resolution may be used.

An example of the spray image photographed by the photographing means is shown in Fig. 3 (a). On the other hand, when a plurality of images are shot, a plurality of spray images can be taken.

Since the spray image photographed in the photographing step S110 is a spray pattern before processing, an image processing process is required to measure the spray pattern and the spray angle (S120). The image processing step S120 may be performed by the data processor 10 of Figs. As shown in FIGS. 5 and 6, the image processing step S120 includes a step S121 of removing the reflected light of the nozzle tip 3 and the non-spray-related part in the atomized image, And storing the distribution of the spray (S122).

In the spray image, the reflected light of the nozzle tip (3) A step of removing a part irrelevant to the spraying may be performed (S121). In Fig. 3, the spray image of (a) can be converted into the spray image of (b).

Next, a step of storing the distribution of the spray may be performed (S122). In the step S122 of storing the spray distribution, the part where the spray is obtained may be converted into a white pixel (1), and the part where the spray is not obtained may be converted into a black pixel (0, black pixel). At this time, the white pixel 1 is converted to white, and the black pixel (0) portion is converted to black. The converted spray image is shown in Fig. 3 (c). Meanwhile, at this stage, it may further include a step of examining the validity of the conversion result through comparison between the converted sprayed distribution and the actual sprayed image.

Next, a step of measuring the spray angle may be performed (S130). The step S130 of measuring the spray angle of the injector 2 according to the embodiment of the present invention is performed such that the spray image processed through the image processing step S120 is farthest from the nozzle tip 3 of the injector 2 And the spray angle is measured using the information on the spray reach distance (R) to the point reached.

The step of measuring the spray angle (S130) may be carried out by the spray angle measuring unit 20. 7, the step of calculating the spraying distance R is performed (S131), and the step of counting the number of white pixels 1 is performed (S132). Third, a step of calculating the area of the sector formed by the white pixel (1) is performed (S133). Finally, a step between the width of the sector and the imaginary circle width (S134) of calculating a spray angle from the relationship between the spray angle and the spray angle.

First, a step of calculating the spray reach distance R may be performed (S131). Here, the spray reach distance R refers to the length from the nozzle tip 3 to the white pixel 1 located farthest from the nozzle tip 3, as shown in FIGS.

Second, a step of counting the number of white pixels 1 may be performed (S132). The step S132 of counting the number of white pixels 1 is performed by calculating a counting reference distance r corresponding to a preset ratio in the spray reach distance R and then counting the counting reference distance r from the nozzle tip 3, (r) as a radius, and counts the number of white pixels (1) existing within the circular arc.

More specifically, the counting reference distance r according to the present invention is a length corresponding to a predetermined ratio (for example, 1/3 of the spray reach distance R in FIG. 4) of the spray reach distance R And the counting reference distance r can also be calculated when the spray reach distance R is calculated. Referring to FIG. 4, FIG. 4 illustrates a process of meshing a portion of the spray image in FIG. 3 to count the number of white pixels 1 located within the counting reference distance r. At this time, it is possible to form a virtual arc having the radius of the counting reference distance r, but the number of white pixels 1 arranged in the virtual arc can be counted. This refers to setting the spray angle to a liquid mainly located within 1/3 of the spray reach distance R from the nozzle tip 3 on the image.

Next, a step of calculating the width A of the sector can be performed. The width A of the sector means the area occupied by the white pixel 1 counted in the virtual arc in the previous step. That is, the shape of the portion counted by the white pixel 1 in the previous step can be assumed to be a circular sector whose radius r is 1/3 of the spray reach distance R, The number can be calculated.

) 사이의 관계로부터 분무각을 계산하는 단계가 수행될 수 있다. Finally, the width (A) of the sector and the imaginary circle width formed by the arc

) May be performed from the relationship between the spray angle and the spray angle.

) 의 관계로부터 도출될 수 있다.The spray angle can be calculated from the following equation (1). [Equation 1] is the sum of the width A of the sector and the imaginary circle width of the arc

). ≪ / RTI >

[Equation 1]

) * 360°The width of the sector (A) / the imaginary circle width formed by the arc (

) * 360 °

The spray angle can be measured using the reference for calculating the spray angle from the information on the reach distance of the sprayed image through the steps described above. Thus, even after the spray is developed at a certain level or more, Results can be obtained.

Further, it is possible to more easily study the efficiency improvement of the engine such as the fuel injection amount and the injection timing based on the accurate spray angle information.

FIG. 8 is a view showing a measurement result of the spray angle obtained by the conventional spray angle measurement result and the spray angle measurement method of the injector according to the embodiment of the present invention.

The measurement results will be described with reference to Figs. 1 to 8 using the spray angle measuring method of the injector having such a configuration. The spray angle measurement method of the injector according to the embodiment of the present invention can be implemented using a commercially available MATLAB program or the like. It is easier and easier to carry out measurement experiments when using commercial packages.

The pressure applied to the injector was 100 Mpa and the measurement time was 1.3 ms. The change of spray angle was measured according to the change of the internal density of the cylinder.

As shown in FIG. 8, the conventional measurement method and the spray angle measurement method of the injector according to the embodiment of the present invention were used for the same experimental conditions. As a result, the dispersion range was reduced, and more stable and accurate results were obtained Can be obtained.

Referring to FIG. 8A, it can be seen that the spray angle measured with passage of time to the injector 2 is not stabilized and the dispersion (deviation) is severe. This is because the conventional measurement method is a measurement standard This is because it is computed by selecting different outermost points for each image. In the case of using the spray angle measurement method of the present invention, it can be seen that this deviation is significantly reduced with reference to FIG. 8 (b).

By using this method, the spray angle can be measured from the information on the spray reach distance R. [ As a result, it is possible to obtain stable and accurate measurement results even after the spray is developed not only at the initial stage but also at a certain level or more.

In addition, it is possible to more easily study the efficiency improvement of the engine such as the fuel injection amount and injection timing through the spray behavior information of the actual injector 2.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims (7)

An image processing step of processing the spray image; And
Measuring a spray angle from information about a spray reach distance from a nozzle tip of the injector to a point farthest from the spray image in the spray image processed through the image processing step,
Wherein the image processing step comprises: removing the reflected light of the nozzle tip and the non-spray-related portion in the spray image; And converting the spray image to black and white to store the distribution of the spray.
The method according to claim 1,
Prior to the image processing step,
Further comprising the step of photographing the spray image from a spray sprayed from a nozzle tip of the injector.
delete The method according to claim 1,
Wherein the step of storing the distribution of the spray converts the portion where the spray is acquired into the white pixel and the portion where the spray is not acquired is converted into the black pixel and stores it.
5. The method of claim 4,
Wherein the step of measuring the spray angle comprises:
Calculating the spray reach distance;
Calculating a counting reference distance corresponding to a preset ratio in the spray reach distance, forming a virtual arc having a radius of the counting reference distance from the nozzle tip, and counting the number of white pixels existing within the arc;
Calculating an area of the sector from the counted number of white pixels; And
And calculating a spray angle from the relationship between the width of the sector and the imaginary circle width formed by the arc.
6. The method of claim 5,
Wherein the spray reaching distance is a length from the nozzle tip to the white pixel located farthest from the nozzle tip.
6. The method of claim 5,
The spray angle
Is calculated from a relation of the width of the sector / the imaginary circle width * 360 formed by the arc.

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