JPS61210918A - Spectrochemical analyzing method for combustion flame of reciprocating internal-combustion engine - Google Patents

Abstract

PURPOSE:To facilitate the spectrochemical analysis of the combustion flame of a reciprocating internal combustion engine by converting data to spectral illuminance by taking the attenuation rate of a flame image into consideration. CONSTITUTION:A spectroscope is operated at a specific wavelength and the spectral illuminance of the light transmitted through soot in the wavelength region thereof is detected by a light power meter. The data measured by a similar method in the state perior to sticking of soot is separately obtd. The data 77 on the attenuation rate of the flame image propagation at specific wavelengths lambda1-lambda4 by the sticking of the soot is obtd. from the difference between such data and the data obtd. in soot sticking stage. The data 77 is stored into an RAM65 in an analyzer 61 contg. an arithmetic element, storage element, etc. automatically or by a manual operation from the outside. On the other hand, the data on the information on the analysis illuminance of the flame image, etc. converted and stored at an electrical level into a data recorder is inputted to a CPU64. The data on the attenuation rate of the soot from the RAM65 is also inputted to the CPU64. The CPU64 reads out the necessary information from an ROM66 from two sets of the data and calculates the spectral illuminance corresponding to the engine stroke by taking the attenuation rate of the flame image propagation by the influence of the soot into consideration.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to spectroscopic analysis of combustion flames (hereinafter referred to as "engines").

(Technical background of the invention and their sum) In order to detect the details of the combustion situation in the high-temperature, high-pressure combustion chamber inside the engine, it is necessary to transmit the light energy generated during combustion (hereinafter referred to as the flame image) to the outside (transmission). It is necessary to perform so-called spectral analysis by analyzing the flame image that has spread and propagated using a spectrometer at the spectrometer.In order to perform this analysis, a viewing window is installed in the combustion chamber, and the It is necessary to guide the flame image to the analyzer. However, it is not easy to install a permanent heat-resistant and pressure-resistant window in the combustion chamber of an actual engine (and even if it could be installed, However, it has been extremely difficult to perform accurate spectroscopic analysis of actual equipment in wet conditions due to the flame image caused by soot adhering to the window surface.

(Summary of the Invention) Recently, a mounting bracket having a light guide such as an optical fiber hermetically penetrated inside the engine combustion chamber partition wall is installed, and the light guide incident surface is placed opposite to the combustion flame. A method of transmitting the image to the outside was devised, and a typical example is fi+ 176861 (August 27, 1982). By using such mounting brackets, it is not only easy to transmit the flame image to the outside, but also because the device itself is highly durable, making it possible to grasp the actual state of combustion in actual equipment, even in wet conditions. .

In addition, if an optical fiber or the like is used as a single light guide when dispersing the flame image transmitted to the outside, the complicated work of aligning the optical axis during spectroscopy can be omitted, and the efficiency can be improved by using the minimum light energy. Regarding the problem of soot, which is extremely easy to adhere to, first convert the flame image to an electrical level and record it, then check whether the mounting bracket is on the combustion chamber bulkhead, take into account the attenuation thus investigated, and then This effect can be eliminated by converting the recorded data into spectral brightness or illuminance (hereinafter referred to as illuminance). A feature of the present invention is that the combustion flame of a reciprocating internal combustion engine is spectroscopically analyzed by such a method.

(Embodiments of the Invention) Various embodiments of the present invention are possible, but in the embodiment described below, after the operation of the engine for data collection is completed,
Let's discuss how to investigate the reduction of soot attached to the light guide entrance surface and correct the collected data when performing spectroscopic analysis based on the results.

FIG. 1 is a concept showing an example in which the present invention is implemented in a known pre-combustion chamber type diesel engine. A sub-combustion chamber 5 is provided on the side thereof. A fuel injection valve 6 is attached to the auxiliary combustion chamber 5, and fuel injected from the valve flows into the combustion chamber 3, is adiabatically compressed by the piston 7, and ignites and burns.

Reference numeral 11 denotes a mounting bracket having a structure whose details will be described later and has a light guide that penetrates the combustion chamber partition wall 10 in an airtight manner, and is installed to pass through the combustion chamber partition wall 10 in an airtight manner, and can be easily attached and removed from the partition wall using screws. The configuration is such that it can be done. Mounting bracket 1
A light beam 11 that receives a flame image generated in the sub-combustion chamber 5 is attached to the tip of the sub-combustion chamber 5 by a screw, and a tapered surface 32 is attached to the sub-combustion chamber 5 side.
is formed. 33 is a through hole formed in the longitudinal direction of the mounting bracket 11, 34 is a rod-shaped optical fiber serving as a light guide, 35 is an entrance surface of the optical fiber, 36 is an output surface of the optical fiber, and 37 is a rod-shaped optical fiber that serves as a light guide. A first support that supports the entrance surface 35 side of the fiber 34, which supports the optical fiber 34.
In order to absorb the aberration caused by heat between the optical fiber 34 and the optical fiber 34, it is slidable in the fine (longitudinal) direction of the optical fiber 34, and is fixed to the through hole 33 of the mounting bracket 11 with a screw. . 38 is a see-through window attached to the side of the sub-combustion chamber 5 of the support 37, and the one shown is a lens-shaped one that transmits the flame image in the sub-combustion chamber 5 and condenses the light. A fixing agent that is made of artificial sapphire, which has a high melting point, heat resistance, pressure resistance, good light and heat transmission, and is resistant to corrosion, and has heat resistance and airtightness39 The optical fiber 340 portion is hermetically sealed to prevent the optical fiber 340 from being damaged or having its properties deteriorated by high temperature, high pressure gas, shock waves, corrosive gas, etc. generated in the combustion chamber.

As described above, the inside of the auxiliary combustion chamber 5 of the reciprocating internal combustion engine 1 reaches a high temperature that may affect the optical fiber 34 and the like only for a very short time while the fuel is being combusted.

Therefore, it is only necessary to cover the high temperature with the transparent window 38 of the optical fiber <34 for a short period of time. The above-mentioned transparent window 38 is not limited to a lens shape and may be a flat plate shape, but if the optical fiber protection is not required, a different structure without this window may be used. Good too. 40
is a second support that is press-fitted into the main body of the mounting bracket 11, the inner surface of which is flush with the through hole 33 formed in the longitudinal direction of the mounting bracket 11, and a part of the support is in contact with the first support. The fitting 37 is supported in the same way as the mounting fitting 11. Reference numeral 41 indicates a fixing portion made of adhesive for sealing the optical fiber 34 and the second support 40, and 42 indicates a known connecting fitting used to connect the optical fiber 36 to another light guide.

In the mounting bracket 11 having such a configuration, the flame image generated in the sub-combustion chamber 5 enters the entrance surface 35 of the optical fiber 340 through the see-through window 38 and exits from the exit surface 36 to the outside. In addition, various methods can be considered for spectroscopy of the flame image transmitted from the high-temperature, high-pressure combustion chamber to the outside by the mounting bracket 11 provided with a light guide inside, such as heat radiatively transmitted from the sub-combustion chamber 5.

For example, the most common method is to attach a large-diameter optical fiber to the output end of the mounting bracket, branch the flame image using a known splitter, etc., and use multiple known spectrometers at each end of the branched flame image. There is a method of arranging instruments side by side to perform spectroscopy and then converting it to electrical levels. Alternatively, the mounting bracket 1
One possible method is to add a number of light beams to the incident surface of 1 and obtain a nearly continuous spectrum.
Let's explain how to easily disperse flame images using fiber optic fibers and filters.

In FIG. 1, an input end (details of which are shown in FIG. 3) is tied together at the output end (not shown) of the mounting bracket 11, and the output end is divided into a plurality of groups (four in this embodiment). The well-known branch bundle optical fiber 8 is connected to the input end of the optical fiber east 540 connected by the connecting fitting 42 shown in FIG. They are connected using metal fittings 42, 52 and an adapter 51, and the flame image is transmitted to the input end of the optical fiber bundle 54.The output end side of the branched bundle optical fibers 8 is bundled in units of one or more fibers. is,
It is divided into four groups, and the output end of each group is connected to a photoelectric converter 9 including a photoelectric element with high responsiveness and sensitivity, which is preceded by a known bandpass filter that transmits only a specific narrow wavelength range. It is assumed that the spectral sensitivity range of each converter is set to an appropriate value that facilitates the spectroscopic analysis of flame rays. Reference numeral 16 denotes a well-known amplifier with excellent responsiveness, which outputs a voltage corresponding to the spectral illuminance of the light incident on the incident surface of the mounting bracket 11. Note that this output value indicates that the mounting bracket 11 is
The spectral illuminance of a specific wavelength at the entrance surface is calibrated in advance using a known blackbody furnace or a standard light source before installation, and the entrance end of the mounting bracket 11 is not contaminated by soot, etc. can be detected from the output voltage of the amplifier 16, and the thus detected output is sent to a known data recorder 54.
is input and recorded. 55 is a known crank angle detector, and 56 is a known pulse type tachometer, both of which are attached to the camshaft and crankshaft of the engine 1, and when the engine is running, they receive data along with the output of the amplifier 16. -Specific crank angle information (stroke position it, ) and so-called rotation pulses are recorded on the recorder.

Note that the method of using a data recorder to record data is only one embodiment, and instead, a known memory element or the like may be used, and a 701st embodiment will be shown below. FIG. 4 is a block diagram showing the main structure of an external recording device using a known memory element. In the figure, the well-known GT is operated by inputting information (crank angle information) that the engine stroke (crank angle K) is near the combustion start point from the crank angle detector 55, and the crankshaft is rotated at a constant angle. A known counter 5 is connected to the advance angle via a known waveform shaping circuit (not shown).
7 to operate this quanta and address the known storage element 58.

At the same time, the pulse is also output to a well-known AD converter 59, which is activated, and the specific wavelength range flame image converted to an electrical level output from the amplifier 16 is digitally converted and sent to the corresponding address. Data is read using a known method.

Next, when performing spectroscopic analysis from the data recorded in this way, the flame image transmission due to the shadow RkK of soot adhering to the light guide entrance surface of the mounting bracket 11 is calculated by comparing the amount of attenuation when the mounting bracket is connected to the sub-combustion chamber. It was removed from the bulkhead 10 and the trap 11
(Let's discuss how to perform the above work, taking into consideration the attenuation amount investigated.

FIG. 5 is a block diagram including a conceptual diagram showing a method of detecting the amount of attenuation of the flame image propagation due to soot attached to the light guide entrance surface of the mounting bracket 11. The mounting bracket 11 removed from the engine 1 has soot attached to it, and a fiber 74 is connected to it, and white light emitted from a standard light source 71 such as a known halogen lamp or a black body furnace is collected in a known condensed state. The light enters through the system 72 and the spectroscope 73, and exits from the light guide entrance surface of the mounting bracket 11, and enters the detector 76 of a known optical power meter 75 mounted there. In such a configuration, by operating the spectrometer 73 at a specific wavelength (specifically, the transmission wavelength of the bandpass filter of the photoelectric converter 9), the optical power meter calculates the fraction of the light that has passed through the soot in that wavelength range. Can detect light illuminance. Furthermore, data measured using the same method under conditions before soot adhesion, or data measured again with soot removed after the measurement work was completed, was obtained, and the difference between this and the data when soot adhesion was determined. By calculating, each specific wavelength λ1 by soot ykK
Attenuation amount data 77 of flame image propagation in ~14 is obtained.

Next, when the attenuation amount is determined manually, the position of the diffraction grating in the spectrometer 73 (not shown) is detected by a known method (not shown) to indicate that the spectrometer 73 is set to the wavelength in question. This is then stored in a known storage element 80 via the spectral illuminance converter 79 of the wavelength detected by the optical power meter 75. Thereafter, similar measurements are repeated for other specific wavelengths, and the spectral illuminance of the specific wavelengths λ~λ4 detected by the optical power meter with soot attached is memorized. Next, after removing the mounting bracket 11 and removing the soot, measure the spectral illuminance of the specific wavelength in this state using the same method as described above according to the measurement mode instruction from the outside, and also obtain this data. Memory element 80
to memory. Next, in accordance with an external measurement mode instruction given to the arithmetic element 82, the arithmetic element 82 calculates the spectral illuminance of the same wavelength for the two data stored in the storage element 80 using a known method, and Attenuation data similar to the above is obtained and outputted to a memory element 6FIK built into the analyzer 61, which will be described in detail later.

Next, a method for performing spectroscopic analysis of a flame image will be described with reference to FIG. 1, taking into consideration the data attenuation data from aiC obtained in this manner. The soot attenuation amount data 77 obtained by the method described in FIG. is stored in memory.

Under these circumstances, use it as a data recorder! Data such as the spectral illuminance of the flame image converted and recorded at the atmospheric level and crank angle information are input to an analyzer 61 and sent to an arithmetic element via a known AD converter 62, a waveform shaping circuit 63, etc. 64. Soot attenuation data is also input to the same element from the memory element 65.

The arithmetic element 64 calculates the spectral illuminance according to the crank angle from the above two data by converting the electric level that can be visualized into the illuminance, a calibration value, a calculation formula, and an illuminance correction calculation based on the attenuation amount of soot. Information such as formulas is read out from the memory element 66, and based on this information, the spectral illuminance according to the engine stroke is calculated based on the attenuation amount of the flame image due to the influence of soot. The measured values thus calculated are outputted to the plotter 68 via a built-in known drive circuit 67, thus obtaining the originally intended measured data 69.

Note that instead of collecting the electrical level (converted and recorded spectral illuminance of the flame image with the data recorder 54), if it is stored in memory using a storage element as shown in FIG.
The stored data can be easily transferred to the arithmetic element 64 in the analyzer 61 using a known data bus, or the element 58 itself may be built into the analyzer 61.

Although an example has been described in which the data recorder 54 is used to record a flame image on a time-based basis and in memory element implementation, this is not limiting.

The number of measurements of the flame image is not particularly mentioned in the embodiment just described, but if there is almost no change in the state of soot adhesion, the number of measurements may be set to a large number. Furthermore, even if the condition of adhering soot changes significantly due to combustion, etc., the fuel supply can be stopped using a quick-response fuel cutoff valve during strokes other than those in which fuel is being supplied while the engine is running. If a method is adopted in which the mounting bracket 11 is then removed and soot attenuation data is collected, flame image spectroscopic analysis during the final combustion stroke during engine operation can be performed with high accuracy.

Furthermore, in the embodiments described so far, when flame propagation is caused by soot adhesion, the attenuation evaluation method measures the amount of attenuation itself and corrects the measured data. An example of using a value calibrated in a state t without the use of t has been described. However, as an alternative method, you do not calibrate the electrical level at all in advance, but first operate the engine and record the data on a data recorder, etc., and then
, 11 was dumped and put into a black body furnace with soot still attached.
Alternatively, calibrate the electrical level using a standard light source, etc.
The recorded data at an astonishing level may be directly converted into spectral illuminance using the calibration value thus obtained. When this method is adopted, spectroscopic analysis data can be obtained by almost the same method as described in Figure 1, but in this example as well, the basic idea is that the measurement data is converted to spectral illuminance. At this time, the amount of attenuation due to the shadow 411 of soot attached to the light guide entrance surface is investigated by removing the mounting bracket, and the data is converted into spectral illuminance by taking into consideration the amount of attenuation thus investigated. The way of thinking is the same.

Furthermore, as another embodiment, if there is no problem even if the state of soot adhesion changes, the recording on the data recorder is omitted in the embodiment described in FIG. After manually inputting the analyzer 61, the output of the amplifier 16 may be directly input to the analyzer 61 to perform spectroscopic analysis.

(Effects of the Invention) By stirring the method as described above, it is possible to perform spectroscopic analysis of the engine flame while eliminating the effects of soot and the like.

[Brief explanation of the drawing]

Fig. 1 is a structural conceptual diagram showing an embodiment of the present invention, Fig. 2 is a side cross-sectional view showing an embodiment of a mounting bracket having a light guide hermetically penetrated therein, and Fig. 3 is a branch bundle. Fig. 4 is a block diagram showing the main components of a data recording device using a memory element; Fig. 5 is a side sectional view showing how to connect optical fibers; Fig. 5 is a block diagram showing the main components of a data recording device using a storage element; FIG. 3 is a conceptual diagram showing a method for detecting the amount of attenuation. Branch bundle optical 7 eyeball, 9... photoelectric converter, 51.
...Adapter, 61...Analyzer. Designated Agent: Tatsuzo Honma, Director of Legal Affairs Division, Office of the President of National Railways

Claims (1)

[Scope of Claims] 1) A mounting bracket provided with a light guide airtightly penetrating the inside thereof is installed in a reciprocating internal combustion engine combustion chamber partition wall in an easily attachable/detachable state so as to airtightly penetrate the partition wall; By placing the guide entrance surface facing the flame in the combustion chamber, the combustion flame image was transmitted to an external spectrometer for spectroscopy, and the thus spectroscopic flame image was converted to an electrical level by a photoelectric conversion device installed on the output side of the spectrometer. Later, the level is stored in the storage device according to the engine stroke, and when converting the stored data to spectral illuminance, the amount of attenuation during propagation of the flame image due to the influence of soot adhering to the light guide entrance surface is calculated as described above. A method for spectroscopic analysis of a combustion flame in a reciprocating internal combustion engine, characterized in that the metal fitting is investigated by removing it from the combustion chamber partition wall, and the data is converted into spectral illuminance by taking into consideration the attenuation thus investigated. 2) The spectroscopic flame image is converted into an electrical level by a photoelectric conversion device provided on the output side of the spectrometer, and then stored in a storage device, and the level is stored according to time instead of engine stroke. A method for spectroscopic analysis of combustion flame in a reciprocating internal combustion engine according to claim 1. 3) Install a mounting bracket with a light guide airtightly passing through the partition wall of a combustion chamber of a reciprocating internal combustion engine in an easily attachable/detachable state, and install the mounting bracket airtightly through the partition wall of the combustion chamber of a reciprocating internal combustion engine. By installing the combustion flame image opposite to the chamber flame, the combustion flame image is transmitted to an external spectrometer for spectroscopy, and the resulting flame image is converted into spectral illuminance via a photoelectric conversion device installed on the output side of the spectrometer. Investigating in advance the amount of attenuation during propagation of the flame image due to the influence of soot adhering to the entrance surface by removing the mounting bracket from the combustion chamber partition,
A method for spectroscopic analysis of a combustion flame in a reciprocating internal combustion engine, characterized in that the level is converted into spectral illuminance by taking into account the amount of attenuation investigated in this manner.