JP3303501B2 - Liquid spray volume measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a volume of a liquid spray such as a fuel spray of a combustion engine, and more particularly to a device capable of acquiring three-dimensional shape information with a simple structure and performing a highly accurate volume measurement. The present invention relates to an apparatus for measuring the volume of a liquid spray that can be formed.

[0002]

2. Description of the Related Art In the process of developing and researching a fuel injection system of a combustion engine such as a diesel engine or a gasoline engine, it is important to know the volume of fuel spray by the fuel injection system. Since it is not possible to directly measure the volume of the fuel spray, it is common to observe the external shape of the fuel spray and estimate the volume from this external shape. Conventionally, to measure the volume of liquid spray by estimating from such a shape, a photograph taken with a high-speed camera is used, and the image is processed to extract the shape of the liquid spray, and the volume is estimated from this shape. Is going.

FIG. 6A shows a basic configuration of the volume measuring device. As shown in the figure, a light source 61 such as a laser and a high-speed camera 62 are arranged on both sides of a fuel injection system 63 so that a side projection image of the fuel spray 64 can be photographed. By photographing at a high speed, a photograph 65 as shown in FIG. 6B showing the momentary side shape of the growing fuel spray 64 is obtained. From the fuel spray image 66 of the photograph 65, the volume at each time point is estimated.

[0004]

By the way, the volume is estimated from the photograph of one side as in the prior art because the shape of the liquid spray 64 is roughly axially symmetric with respect to the axis of the liquid spray 64. Based on the foresight. However, in practice, the shape of the liquid spray is not always axially symmetric. For example, as shown in FIG. 7A, a liquid material spray 71 having a shape in which only a certain angle is distorted is set to the angle (arrow).
7 (b), the distorted portion 72 does not appear in the photograph taken in this way. FIG.
A photograph as shown in (b) is obtained. Therefore, the estimated volume becomes inaccurate. As described above, since the three-dimensional shape of the liquid spray cannot be known from observation from one side using the two-dimensional information of a photograph, the volume cannot be accurately measured in the past.

[0005] The technique disclosed in Japanese Patent Application No. 53-3555 (Japanese Patent Application Laid-Open No. 54-96625) attempts to compensate for the drawbacks caused by observation from one side in the verification of the three-dimensional angle and shape of the spray. Things. However, it is sufficient for mere determination of pass / fail, but is not suitable for precise volume measurement in the process of developing and researching an injection system. That is, this technique irradiates a plurality of strobe light sources from different directions, and observes the light quantity at the reference position of the shadow image in each direction. Although the strobe light source and the detector are provided in two or more directions,
A strobe light source cannot be used at the same time in order to obtain light amount information of a shadow image in each detection unit. Further, even if a high-speed camera is replaced with a detection unit, operating two or more high-speed cameras and a strobe light source at the same time cannot eliminate a mechanical delay or the like even if an electric trigger is synchronized. Because it is difficult. Therefore, the shape information obtained from two or more directions always has a time lag. Since the fuel spray grows every moment, the volume of the fuel spray cannot be accurately obtained from the shape information having a time lag. In addition, since high-speed cameras are very expensive, it is economically difficult to use a plurality of high-speed cameras.

Accordingly, an object of the present invention is to solve the above problems and to provide a liquid spray volume measuring apparatus capable of acquiring three-dimensional shape information with a simple configuration and performing volume measurement with high accuracy.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a light source for irradiating parallel light to a liquid spray from a plurality of directions perpendicular to the axis of the liquid spray, and a light source opposite to the liquid spray. A plurality of reflecting means for aligning and reflecting these parallel lights in the same direction, an imaging means for receiving the aligned parallel lights and imaging the liquid spray images from a plurality of directions, and And a volume estimating means for calculating the volume of the liquid spray based on the three-dimensional contour.

The above-mentioned contour estimating means measures the diameter of the liquid spray image in each irradiation direction at predetermined intervals in the axial direction of the liquid spray image, and estimates the cross-sectional contour by interpolating between the irradiation directions. Good.

The light source may include a laser oscillator for generating a laser beam, and a plurality of emission ends coupled to the laser oscillator via an optical fiber and arranged around the axis of the liquid spray. .

[0010]

With the above arrangement, the light source irradiates the liquid spray with parallel light from a plurality of directions orthogonal to the axis of the liquid spray. In each direction, since the parallel light is radiated, a parallel light carrying accurate lateral shape information of the liquid spray is obtained on the opposite side of the liquid spray. The plurality of reflecting means reflect parallel lights in the respective directions in the same direction. Therefore, the parallel light reflected in the same direction carries accurate side shape information of the liquid spray in a plurality of directions.

The imaging means receives the aligned parallel light and images liquid spray images from a plurality of directions. Since the plurality of imaged liquid spray images each represent a side shape at the same time, the contour estimating means estimates an instantaneous three-dimensional contour of the liquid spray that grows from these liquid spray images. Can be. The volume calculation means calculates the volume of the liquid spray based on the three-dimensional contour.

The three-dimensional contour estimating method of the contour estimating means estimates a cross-sectional contour at predetermined intervals in the axial direction of the liquid spray image.
That is, each sectional contour is estimated by cutting the liquid spray at right angles to the axis, and a three-dimensional contour is obtained by arranging these sectional contours in the axial direction. The cross-sectional contour is estimated by measuring the diameter of the liquid spray image for each irradiation direction. Two points of the cross-sectional contour are obtained from the diameter of the liquid spray image in one direction, and a plurality of measurement points on the cross-sectional contour can be obtained by arranging these points around the axis in the direction. At this time, by interpolating between the irradiation directions by linear interpolation or Lagrangian interpolation, it is possible to estimate a sectional contour close to the actual contour from a finite number of measurement points. In this case, the calculation of the volume involves calculating the area of each cross section and further integrating the area of this cross section in the axial direction.

The light source may be provided independently around the axis of the liquid spray for each irradiation direction. However, a plurality of optical fibers are branched from one laser oscillator, and these optical fibers are used for the liquid spray. It is also possible to combine with a plurality of emission ends arranged around the axis.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1A shows the configuration of an optical system of a liquid spray volume measuring apparatus according to the present invention. The light source 1 includes a laser oscillator 2 for generating laser light, and a plurality of emission ends 5 coupled to the laser oscillator 2 via an optical fiber 3 and arranged around the axis of the liquid spray 4. I have. In this embodiment, three emission ends 5 arranged at intervals of approximately 120 ° are provided. The parallel light L emitted from the emission end 5 has a predetermined width wider than the diameter of the liquid spray 4 to be measured as shown in the figure, and is perpendicular to the plane of the drawing (the axial direction of the liquid spray). The parallel light L having a rectangular shape in cross section and having a predetermined width larger than the length of the liquid spray 4. Each emission end 5
Are arranged so as to face the liquid spray from the side surface so as to be orthogonal to the injection axis direction of an injection system (not shown). In this manner, the light source 1 that distributes the laser light from the single laser oscillator 2 to the three emission ends 5 and irradiates the liquid spray with the parallel light L from three directions orthogonal to the axis of the liquid spray is formed. Have been.

The reflecting means 6 comprises a plane mirror 7. In this embodiment, since one of the emission ends 5 faces the imaging means described later, there is no plane mirror 7 corresponding to the emission end 5, and two plane mirrors 7 are provided for the remaining emission ends 5. It is provided in. Each plane mirror 7 is disposed on the opposite side of the liquid spray 4 from the corresponding output end 5 and has a predetermined inclination angle with respect to the corresponding output end 5. This tilt angle is
The parallel light L from the opposite side of the liquid spray 4 is set to be reflected in the same direction as the parallel light L from the exit end 5 without the plane mirror 7. As shown in the figure, the respective parallel lights L do not overlap each other.

The imaging means 8 comprises a high-speed camera 9 for performing a high-speed shutter operation and film feeding, and an objective lens 10 placed in front of the camera, and is arranged to face one of the above-mentioned emission ends 5. Have been. The objective lens 10
The aligned parallel light L is focused on the high-speed camera 9. The high-speed camera 9 captures the collected light and forms an image on an internal film surface. In this manner, three liquid spray images having the different directions are picked up at a predetermined magnification on one frame of the film accommodated in the high-speed camera 9.

FIG. 2 shows a system configuration for measuring the volume from the liquid spray image picked up by the image pickup means 8. In this example, the imaging means 8 can use two types of the high-speed camera 9 and the high-speed video 21 described above. When the high-speed camera 9 is used, a photographic film is loaded into a known film motion analyzer 22. RGB signals as image data of the high-speed video 21 or the film motion analyzer 22 are input to the image processing device 23. The image processing device 23 extracts the coordinate data of the contour of the object by processing the image data, and estimates the three-dimensional contour of the liquid spray from the liquid spray image obtained by the imaging means 8. Used as means 24. A specific method for estimating the contour from the coordinate data will be described later.

The image processing device 23 has RS-232C, G
The host computer 25 is connected via a communication line such as P-IB. The host computer 25 is a volume calculating means 26 for calculating the volume of the liquid spray. The host computer 25 can process the contour estimation result by a volume calculation program and output a volume measurement result. A specific calculation method of the volume will be described later.

Next, the operation of the embodiment will be described.

In FIG. 1, laser light from a laser oscillator 2 is distributed by an optical fiber 3 and has three emission ends 5.
Are emitted as parallel light L. The parallel light L passes through the ejection axis of the ejection system at right angles, and directly goes where the plane mirror 7 is not provided.
Where the plane mirror 7 is located, the light is reflected by the plane mirror 7 and reaches the objective lens 10 without overlapping each other. At this time, each parallel light L can map, at the position of the objective lens 10, the side surface shape in each direction of the object between the emission end 5 and the objective lens 10 at the same magnification regardless of the optical path distance. . The objective lens 10 condenses these parallel lights L on the high-speed camera 9.

When the operation of the high-speed camera 9 is started in synchronization with the ejection operation of the ejection system, the state of the growing liquid spray is continuously imaged. On the film (one frame), the liquid material spray images in the respective directions by the three parallel lights L appear at the same magnification. FIG. 1B shows an example of the film. On the film 11, three liquid spray images 12 at the same moment are shown side by side. Reference numeral 13 denotes a tip of the injection system. Here, since the light sources are in three directions, scattered light from the liquid spray may appear, but in the present invention, the effect of the scattered light can be neglected since it is only necessary to estimate the contour.

Next, the procedure for estimating the contour and calculating the volume using this film in the system of FIG. 2 is shown in FIG.
This will be described with reference to FIG. 4B and FIG.

First, the coordinates of the contour points Pi1 to Pi6 at an arbitrary position (indicated by a broken line) in the axial direction (Z direction) of the liquid spray of each liquid spray image on the film 11 in FIG. Perform detection. This detection can be performed by performing known image processing such as filtering and binarization to separate the liquid spray image from the background. Next, these points are assigned to each liquid spray image, and the distance from the coordinates corresponding to the axis of the liquid spray is calculated. Multiply this distance by a magnification,
Convert to the actual diameter r. The point represented by the diameter r is mapped to the polar coordinates of FIG. Since the angle θ of each point is clear from the configuration of FIG. 1, Pi5, Pi3,... Are arranged in the order of the angle θ. Next, as shown in FIG. 4B, in a coordinate system in which the angle θ is developed into a straight line, the space between the points is filled by linear interpolation (linear interpolation), and the radius r
To obtain an approximate continuous change curve. When this is returned to polar coordinates, a closed figure of FIG. 4C is obtained. This shows the cross-sectional contour at the above position in the Z direction. In addition,
FIG. 4D shows a state in which the space between the points is filled by Lagrange interpolation, and the cross-sectional profile of FIG. 4E is obtained. As described above, by using an appropriate interpolation method, it is possible to estimate a cross-sectional contour to a desired accuracy without using a large number of emission ends 5 and plane mirrors 7.

By shifting the position in the Z direction, a sectional contour at each position along the axis can be obtained, so that the three-dimensional contour of the liquid spray can be estimated. Since the contour in the axial direction of each liquid spray image is continuous, a continuous three-dimensional contour can be obtained. However, sampling may be performed discretely. In the present embodiment, this is shown in FIG. Sampling is performed at intervals of ΔZ.

FIG. 5 shows positions Zi (i = 1,
2,..., 5) show the outline of each cross section 51 obtained by the above method. Here, the area Si (i = 1, 2,..., 5) of each cross section 51 can be calculated by a known method. Therefore, the volume V of the liquid spray
To

[0027]

(Equation 1)

As described above, the area Si is obtained by integrating the area Si in the Z direction.

Next, another embodiment will be described.

The system shown in FIG. 3 is an inexpensive system that does not use the image processing device 23 for automatically extracting the coordinate data of the contour. The photographic film obtained by the high-speed camera 9 is placed on the digitizer 31 or the tabletop projection device 32. In the case of the digitizer 31, when each point on the contour is manually specified, the coordinate data is RS-232C, GP-I
B is transmitted to the personal computer 33 via a communication line such as B. In the case of the tabletop projector 32, the coordinate data obtained by reading the scale is manually input to the personal computer 33. The personal computer 33 outputs a volume by executing the contour estimation program based on the polar coordinate conversion and interpolation algorithm and the volume calculation program.

[0031]

The present invention exhibits the following excellent effects.

(1) Since images from a plurality of directions can be contained on one screen (one frame), the three-dimensional shape and volume can be accurately known, and images at the same moment can be obtained. Even if the object is suddenly deformed, the inaccuracy due to the time lag is eliminated.

(2) Since only one imaging means is required, the configuration is simple. This configuration is economical because imaging means such as high speed cameras are generally expensive.

[Brief description of the drawings]

FIG. 1A is a configuration diagram of an optical system of a volume measuring device according to an embodiment of the present invention, and FIG. 1B is a diagram of a photographed film.

FIG. 2 is a configuration diagram of a system for measuring a volume from a liquid spray image according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a system for measuring a volume from a liquid spray image according to another embodiment of the present invention.

FIG. 4 is a diagram showing an algorithm for estimating a contour.

FIG. 5 is a diagram showing an algorithm for calculating a volume.

FIG. 6A is a configuration diagram of an optical system of a conventional volume measuring device, and FIG. 6B is a diagram of a photographed film.

FIG. 7A is a side view of the liquid spray, and FIG. 7B is a side view of the liquid spray viewed from another angle.

[Explanation of symbols]

 Reference Signs List 1 light source 4 liquid spray 6 reflecting means 12 liquid spray image 24 contour estimating means 26 volume calculating means

──────────────────────────────────────────────────続 き Continuation of front page (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01F 11/00 F02M 65/00

Claims (3)

(57) [Claims] 1. A light source for irradiating parallel light to a liquid spray from a plurality of directions orthogonal to the axis of the liquid spray, and a plurality of light sources for reflecting these parallel lights from the opposite side of the liquid spray in the same direction. A reflection unit, an imaging unit that receives the aligned parallel light and captures a liquid spray image from a plurality of directions, and a contour estimation unit that estimates a three-dimensional contour of the liquid spray from these liquid spray images. And a volume calculating means for calculating a volume of the liquid spray based on the three-dimensional contour. 2. The contour estimating means measures the diameter of the liquid spray image in each irradiation direction at predetermined intervals in the axial direction of the liquid spray image, and estimates the cross-sectional contour by interpolating between the irradiation directions. The volume measuring device for a liquid spray according to claim 1, wherein: 3. The light source comprises: a laser oscillator for generating a laser beam; and a plurality of emission ends coupled to the laser oscillator via an optical fiber and arranged around an axis of the liquid spray. The volume measuring device for a liquid spray according to claim 1 or 2, wherein: