阅读说明：本技术 一种基于光学发动机联合测量碳烟前驱物和碳烟的装置及方法 (Device and method for jointly measuring soot precursor and soot based on optical engine ) 是由 钟汶君 相启龙 何志霞 姜鹏 颜飞斌 王谦 于 2019-08-22 设计创作，主要内容包括：本发明涉及发动机燃烧性能测试技术,提供一种基于光学发动机联合测量碳烟前驱物和碳烟的装置及方法,利用波长为355nm的激光激发诱导PAH基的荧光信号以及波长为532nm的激光诱导炽光信号来测量燃烧情况下碳烟前驱物和碳烟空间分布,通过PAH与碳烟出现的时序差异以及信号的衰减速率,通过控制拍摄策略,成功获得一次喷雾燃烧过程中的PAH和碳烟图像,实现了对动力机械系统燃烧条件下碳烟的前驱发展及碳烟空间分布的联合测量。本试验装置由光学发动机系统、激光系统、燃油供给系统、信号同步系统、数据采集系统组成。该试验装置能够同时开展光学发动机喷雾燃烧条件下碳烟的PAH基团、碳烟体积分数及其空间分布的试验研究。(The invention relates to an engine combustion performance testing technology, and provides a device and a method for jointly measuring soot precursors and soot based on an optical engine. The test device consists of an optical engine system, a laser system, a fuel supply system, a signal synchronization system and a data acquisition system. The test device can simultaneously carry out the experimental research on the PAH group, the volume fraction and the spatial distribution of the carbon smoke under the spray combustion condition of the optical engine.)

1. A device for jointly measuring soot precursors and soot based on an optical engine is characterized by mainly comprising a laser system, an optical engine main body (5), a fuel oil supply system, an air supply system, a signal synchronization system and an image acquisition system,

the signal synchronization system comprises a computer (2) and a signal synchronizer (3), wherein the computer (2) is used for controlling a fuel supply system and an air supply system to respectively provide fuel and gas for the optical engine main body (5); the control signal synchronizer (3) controls signal acquisition and delay among the laser system, the fuel supply system and the image acquisition system;

the laser system comprises a first YAG laser (1) and a second YAG laser (4);

the image acquisition system comprises a first spectroscope (6), a second spectroscope (15), a 450-band-pass filter (7), a 410 nm-band-pass filter (9), a first ICCD camera (8) and a second ICCD camera (10);

the film coating side of the first spectroscope (6) faces the first ICCD camera (8) and the second ICCD camera (10) and is obliquely arranged, and the inclination angle is 45 degrees; one side of the second beam splitter (15) coated with a film is obliquely arranged facing the first YAG laser (1) and the second YAG laser (4), and the inclination angle is 45 degrees;

the film optical system (16) is arranged on one side of a window of the optical engine main body (5), the second spectroscope (15) is obliquely arranged on the film optical system (16) and the extended line of the center point of the window, the first spectroscope (6) is obliquely arranged on the other side of the film optical system (16), and the geometric centers of the window, the film optical system (16), the second spectroscope (15) and the first spectroscope (6) of the optical engine main body (5) are positioned on the same straight line;

the 450nm band-pass filter (7) and the 410nm band-pass filter (9) are respectively arranged between the first ICCD camera (8), the second ICCD camera (10) and the first spectroscope (6);

the connecting line of the central points of the first ICCD camera (8) and the first spectroscope (6) is vertical to the connecting line of the central points of the second ICCD camera (10) and the second spectroscope (6);

and a first YAG laser (1) is arranged on one side of the second spectroscope (15), and a second YAG laser (4) is arranged on the other side of the second spectroscope.

2. The device for jointly measuring soot precursors and soot based on the optical engine according to claim 1, is characterized in that: the water heater further comprises a circulating water jacket, wherein the circulating water jacket is arranged around the upper piston body of the optical engine (5), and the circulating water jacket is communicated with the heating water tank through a temperature control switch.

3. The device for jointly measuring soot precursors and soot based on the optical engine according to claim 1, is characterized in that: an electric heating wire and a temperature sensor are arranged in an air inlet channel of the optical engine (5), and the electric heating wire and the temperature sensor are externally connected with a temperature control switch.

4. The device for jointly measuring soot precursors and soot based on the optical engine according to claim 1, is characterized in that: the gas supply system comprises an oxygen gas supply device and can control the oxygen content of the supplied gas.

5. The device for jointly measuring soot precursors and soot based on the optical engine according to claim 1, is characterized in that: and a reflector (13) is arranged at the lower end of the optical engine.

6. The device for jointly measuring soot precursors and soot based on the optical engine according to claim 1, is characterized in that: the fuel supply system comprises a high-pressure oil pump (14), a high-pressure common rail pipe (11) and a fuel injector (12); the high-pressure oil pump (14) is connected with the high-pressure common rail pipe (11) through an oil pipe, and the high-pressure common rail pipe is connected with the oil injector (12); the oil injector (12) is positioned at the upper end of the optical engine main body (5).

7. The device for jointly measuring soot precursors and soot based on the optical engine according to claim 1, is characterized in that: the signal synchronizer (3) is a BNC signal synchronizer.

8. The device for jointly measuring soot precursors and soot based on the optical engine according to claim 1, is characterized in that: the optical engine body (5) is a single-cylinder four-stroke optical engine.

9. The measurement method of the device for jointly measuring soot precursor and soot based on the optical engine is characterized by comprising the following steps:

step 1: the synchronous control system adjusts the valve timing and the lift through the valve timing mechanism to realize the timing matching of the fuel injection of the fuel supply system, the computer (2) controls the control signal of the fuel supply system to control the fuel injector (12) to inject the fuel, and then the fuel injector (12) sends a signal to the signal synchronizer (3);

step 2: the signal synchronizer (3) controls laser with the wavelength of 532nm emitted by the first YAG laser (1) and controls the first ICCD camera (8) to take pictures; at the moment, 532nm laser passes through a light sheet system (16) after passing through a spectroscope 1(5) to be converted into a laser light sheet, the laser light sheet irradiates into an optical engine (5) and vertically irradiates on combustion flame, the laser light sheet passes through a first spectroscope (6), is filtered by a 450nm band-pass filter (7) and then is shot by a first ICCD camera (8) to obtain an excited laser-induced blazing light signal, and the measurement of carbon smoke spatial distribution under the combustion condition is carried out;

and step 3: then, the signal synchronizer (3) controls the laser with the wavelength of 355nm emitted by the second YAG laser (4) and controls the second ICCD camera (10) to take a picture; at the moment, 355nm laser passes through a first spectroscope (15) and then passes through a light sheet system (16) to be converted into a laser light sheet, then the laser light sheet is emitted into an optical engine (5) and vertically irradiated on fuel oil spray flame, then the laser light sheet passes through a first spectroscope (6) and a 410nm band-pass filter (9), and finally a laser induced fluorescence signal is obtained by a second ICCD camera (10), so that the measurement of a soot precursor product PAH base is realized.

10. The test method of claim 9, wherein: the shooting gate widths of the first ICCD camera (8) and the second ICCD camera (10) are set to be 200ns and 20ns respectively.

Technical Field

The invention relates to the technical field of engine combustion performance testing, in particular to a device and a method for jointly measuring soot precursors and soot based on an optical engine.

Background

During the working cycle of the power machine, soot is one of the important indexes for evaluating the pollutant emission characteristics of the power machine. Therefore, the country sets strict emission regulations to restrict the emission of the soot, and the research on the generation and development process of the soot precursors and the soot in the combustion process of the power machine is significant for reducing the emission of the soot of the power machine.

In the previous research, researchers mainly focused on the final emission of soot, and the research on the soot precursors, the development process of soot generation during combustion and the quantitative research on soot is less, so that the understanding of the generation mechanism of soot is not very clear, and the tracing is needed to reduce the emission of soot fundamentally. The soot precursor and the soot generation characteristic in combustion have important guiding significance for exploring the soot generation and development mechanism; in addition, through the optical engine system, the development process of the soot precursor and the development process of soot generation can be obtained closer to the actual operation condition of the real engine, and test data support is provided for further understanding the formation of soot pollutants of the power machine.

However, the following difficulties exist in studying soot precursors and soot generated in the combustion process of an engine: the engine combustion is large in fluctuation per cycle, the combustion process is unstable and strong in turbulence, in order to obtain the corresponding soot precursor in the primary combustion process and the soot generation development characteristic in the combustion process, the soot precursor and the soot need to be measured in a combined manner, and meanwhile, the corresponding soot precursor and the soot development characteristic in the primary combustion process are obtained.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a device and a method for jointly measuring soot precursors and soot based on an optical engine, which ensure the test accuracy and better research the combustion emission characteristics of power machinery. The soot precursors and soot are simultaneously spatially distributed and measured under the combustion condition.

To achieve the above object, the present invention adopts the following embodiments:

a device for jointly measuring soot precursors and soot based on an optical engine is characterized by mainly comprising a laser system, an optical engine main body, a fuel supply system, an air supply system, a signal synchronizer and an image acquisition system,

the fuel supply system and the gas supply system respectively provide fuel and gas for the optical engine main body;

the laser system comprises a first YAG laser and a second YAG laser;

the image acquisition system comprises a first spectroscope, a second spectroscope, a 450-band-pass filter, a 410nm band-pass filter, a first ICCD camera, a second ICCD camera and a computer;

one side of the first spectroscope coating film is obliquely arranged facing the first ICCD camera and the second ICCD camera, and the inclination angle is 45 degrees; one side of the second beam splitter coating is obliquely arranged facing the first YAG laser and the second YAG laser, and the inclination angle is 45 degrees;

the sheet optical system is arranged on one side of a window of the optical engine main body, a second spectroscope is obliquely arranged on the sheet optical system and the extension line of the center point of the window, a first spectroscope is obliquely arranged on the other side of the optical engine main body, and the geometric centers of the window, the sheet optical system, the second spectroscope and the first spectroscope of the optical engine main body are positioned on the same straight line;

the 450nm band-pass filter and the 410nm band-pass filter are respectively arranged between the first ICCD camera, the second ICCD camera and the first spectroscope;

the connecting line of the central points of the first ICCD camera and the first spectroscope is in a vertical relation with the connecting line of the central points of the second ICCD camera and the second spectroscope;

a first YAG laser is arranged on one side of the second spectroscope, and a second YAG laser is arranged on the other side of the second spectroscope;

the signal synchronizer is connected with the laser system, the fuel oil supply system and the image acquisition system and controls signal acquisition and delay among the laser system, the fuel oil supply system and the image acquisition system.

Further, the circulating water jacket is arranged around the piston upper body of the optical engine and communicated with the heating water tank through a temperature control switch.

Furthermore, an electric heating wire and a temperature sensor are arranged in an air inlet channel of the optical engine, and the electric heating wire and the temperature sensor are externally connected with a temperature control switch.

Further, the gas supply system includes an oxygen supply device and is capable of controlling the oxygen content in the supplied gas.

Further, a reflector is placed at the lower end of the optical engine.

Further, the fuel supply system comprises a high-pressure oil pump, a high-pressure common rail pipe and a fuel injector; the high-pressure oil pump is connected with the high-pressure common rail pipe through an oil pipe, and the high-pressure common rail pipe is connected with the oil injector; the oil injector is positioned at the upper end of the optical engine main body.

Further, the signal synchronizer is a BNC signal synchronizer.

Further, the optical engine body is a single-cylinder four-stroke optical engine.

The measuring method of the device for jointly measuring the soot precursor and the soot based on the optical engine is characterized by comprising the following steps of:

step 1: the synchronous control system adjusts the gas distribution phase and the lift through the gas distribution phase mechanism to realize the timing matching of the fuel injection of the fuel supply system, the computer controls the control signal of the fuel supply system to control the fuel injection of the fuel injector, and then the fuel injector sends a signal to the signal synchronizer;

step 2: the signal synchronizer controls laser with the wavelength of 532nm emitted by the first YAG laser, and simultaneously controls the first ICCD camera to take pictures; at the moment, 532nm laser passes through the light splitting mirror 1 and then is converted into a beam of laser light, the laser light irradiates into the optical engine and vertically irradiates on combustion flame, the laser light passes through the first light splitting mirror, is filtered by a 450nm band-pass filter and then is shot by a first ICCD camera to obtain an excited laser induced blazing light signal, and the measurement of carbon smoke spatial distribution under the combustion condition is carried out;

and step 3: then, the signal synchronizer controls laser with the wavelength of 355nm emitted by the second YAG laser, and simultaneously controls the second ICCD camera to take pictures; at the moment, 355nm laser passes through a first spectroscope and then passes through a photosystem to be converted into a laser sheet light, then the laser sheet light is emitted into an optical engine and vertically irradiates on fuel oil spray flame, then the laser sheet light passes through the first spectroscope and a 410nm band-pass filter, and finally a laser induced fluorescence signal is obtained by a second ICCD camera, so that the measurement of the carbon smoke precursor product PAH base is realized.

Further, the photographing gate widths of the first and second ICCD cameras are set to 200ns and 20ns, respectively.

The invention has the advantages and obvious effects that:

the invention discloses a device and a method for jointly measuring soot precursors and soot based on an optical engine, which are used for measuring the spatial distribution of the soot precursors and the soot under the combustion condition by utilizing laser excitation induced PAH (polycyclic aromatic hydrocarbon) base fluorescence signals with the wavelength of 355nm and laser induced blazing light signals with the wavelength of 532nm, successfully obtaining PAH (polycyclic aromatic hydrocarbon) and soot images in the process of one-time spray combustion through the time sequence difference of the PAH and the soot and the attenuation rate of the signals and controlling a shooting strategy, and effectively solving the problem that the space of the soot precursors and the soot is difficult to distinguish and measure under the combustion condition. The method realizes synchronous measurement of the soot nascent development and the diffusion process in the fuel oil one-time spray combustion process, solves the problem that the soot precursor and the soot are difficult to obtain simultaneously in the combustion process, is beneficial to deepening the understanding of the soot generation mechanism of the power machinery and provides an optimization scheme from the source.

Drawings

Fig. 1 is a schematic structural diagram of the device for jointly measuring soot precursors and soot based on an optical engine.

In the figure: 1-a first YAG laser, 2-a computer, 3-a signal synchronizer, 4-a second YAG laser, 5-an optical engine body, 6-a first spectroscope, 7-450nm band-pass filter, 8-a first ICCD camera, 9-410nm band-pass filter, 10-a second ICCD camera, 11-a high-pressure common rail pipe, 12-an oil injector, 13-a reflector, 14-a high-pressure oil pump, 15-a second spectroscope and 16-a light system.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.

As shown in fig. 1, the device for jointly measuring soot precursor and soot based on an optical engine mainly comprises a laser system, an optical engine main body 5, a fuel supply system, an air supply system, a signal synchronizer 3 and an image acquisition system. The fuel supply system and the air supply system supply fuel and gas to the optical engine body 5, respectively. The computer 2 of the image acquisition system is connected with the laser system, the fuel supply system and the image acquisition system through a signal synchronizer 3 and controls signal acquisition and delay among the laser system, the fuel supply system and the image acquisition system.

The laser system comprises a first YAG laser 1 and a second YAG laser 4; the image acquisition system comprises a first spectroscope 6, a second spectroscope 15, a 450 band-pass filter 7, a 410nm band-pass filter 9, a first ICCD camera 8, a second ICCD camera 10 and a computer 2; the coated side of the first spectroscope 6 faces the first ICCD camera 8 and the second ICCD camera 10 and is obliquely arranged, and the inclination angle is 45 degrees; one side of the second beam splitter 15, which is coated with a film, is obliquely arranged facing the first YAG laser 1 and the second YAG laser 4, and the inclination angle is 45 degrees; the 450nm band-pass filter 7 and the 410nm band-pass filter 9 are respectively arranged in front of the first ICCD camera 8 and the second ICCD camera 10; the connecting line of the central points of the first ICCD camera 8 and the first spectroscope 6 is vertical to the connecting line of the central points of the front part of the second ICCD camera 10 and the second spectroscope 6; a sheet optical system 16 is arranged on one side of a window of the optical engine main body 5, a second spectroscope 15 is obliquely arranged on the sheet optical system 16 and an extension line of a center point of the window, and a first spectroscope 6 is obliquely arranged on the other side of the window, wherein geometric centers of the window of the optical engine main body 5, the sheet optical system 16, the second spectroscope 15 and the first spectroscope 6 are positioned on the same straight line; one side of the second beam splitter 15 is provided with a first YAG laser 1, the other side is provided with a second YAG laser 4, and the position of the sheet optical system 16 can ensure that the lasers on the two sides can be combined.

Light rays excited in a combustion chamber of an optical engine 5 are respectively led to the front of a first ICCD camera 8 and a second ICCD camera 10 through a 450nm band-pass filter 7 and a 410nm band-pass filter 9 by virtue of the light path arrangement of a first spectroscope 6, and the first ICCD camera 8 and the second ICCD camera 10 respectively shoot soot space distribution and a soot precursor PAH base; the two cameras are connected with the computer 2 through a signal synchronizer 3 and controlled by the computer 2.

The method utilizes laser with wavelength of 532nm emitted by a first YAG laser 1 to measure laser-induced glow, obtains the volume fraction and spatial distribution of soot under the condition of combustion, and utilizes laser with wavelength of 355nm emitted by a second YAG laser 4 to capture fluorescent signals of a precursor PAH base for soot primary generation.

The signal synchronizer 3 is a BNC signal synchronizer, and an interface of the BNC signal synchronizer can transmit radio frequency signals and reduce mutual interference among the signals.

The fuel supply system comprises a high-pressure oil pump 14, a high-pressure common rail pipe 11 and a fuel injector 12; the high-pressure oil pump 14 is connected with the high-pressure common rail pipe 11 through an oil pipe, the high-pressure common rail pipe is further connected with the oil injector 12, and the oil injector 12 is located at the upper end of the optical engine main body 5. The fuel supply system pumps fuel from the fuel tank through the low-pressure fuel pump to the high-pressure fuel pump 14, the high-pressure fuel pump 14 converts low-pressure fuel into high-pressure fuel under the drive of a motor and sends the high-pressure fuel to the high-pressure common rail pipe 11 through the high-pressure fuel pipe, the high-pressure common rail pipe 11 is connected with the fuel injector 12, and the rail pressure of the high-pressure common rail pipe 11, the fuel injection pulse width of the fuel injector 12 and the fuel injection time are controlled through the computer 2. The oil pressure in the oil pipe is accurately controlled, the pressure of the oil pipe is independent of the rotating speed of the engine, and the variation of the oil supply pressure of the optical engine along with the rotating speed of the engine can be greatly reduced, so that the instability of the optical engine is reduced.

The optical engine main body 5 is a single-cylinder four-stroke optical engine, during measurement, the working condition of the optical engine is controlled to be at a low rotating speed, the working condition of the optical engine is dragged back to 1200r/min by the alternating current electric dynamometer, the optical engine works intermittently, and the continuous operation time is generally less than 10 minutes. In order to solve the problems that the quartz glass is difficult to ignite due to low compression ratio and can be polluted due to incomplete combustion, an external control system is required to provide circulating hot water and hot air so as to simulate the heat engine state when an optical engine 5 in an optical engine system works and promote the atomization and evaporation of fuel oil and a tracer. In terms of circulating hot water, a circulating water jacket is arranged around the upper piston body of the optical engine 5 in the optical engine system, hot water is supplied to the circulating water jacket through a heating water tank, a temperature control switch for control is arranged, and the circulating cooling water with controllable temperature ensures that the temperature of an engine cylinder body is 80 ℃. In the aspect of hot air, an electric heating wire and a temperature sensor are arranged in an air inlet channel of the optical engine 5, the electric heating wire and the temperature sensor are externally connected with a temperature control switch, the electric heating wire is used for heating air in the air inlet pipe, the temperature sensor is used for detecting the air temperature in the air inlet pipe in real time, and the temperature control switch is used for switching on and off the electric heating wire so as to ensure that the air temperature in the air inlet pipe is controlled to be about 353K. And different oxygen concentration environments are configured through an air supply system.

The synchronous control system adjusts the valve timing and lift through a valve timing mechanism to realize the timing matching of the oil injection of the oil injector, adopts the synchronizer 3 to synchronously control a YAG-laser I1 signal, a YAG-laser II4 signal, an ICCD camera I8 signal and an ICCD camera I10 signal, and sets the YAG-laser I1, the YAG-laser II4, the ICCD camera I8 and the ICCD camera I10 synchronous signals to be output when only the oil injection signal of the oil injector 12 is triggered, thereby realizing the laser diagnosis of the in-cylinder combustion condition.

The lower end of the optical engine is provided with a reflector 13, so that the oil injection combustion condition in the combustion chamber and the arrangement of the whole light path system can be mastered in real time by observing the reflector, and an oil injector 12 is arranged right above the reflector.

The testing process for jointly measuring the soot precursor and the soot device based on the optical engine comprises the following steps:

step 1: the computer 2 sends a signal to a fuel supply system to control the fuel injector 12 to inject fuel, and then the fuel injector 12 sends a signal to the BNC signal synchronizer 3; the synchronizer 3 respectively sends signals to the first YAG laser 1, the second YAG laser 4, the first ICCD camera 8 and the first ICCD camera 10, so that the laser triggering and the camera acquisition time sequence are synchronized, and the computer 2 controls all systems to synchronously run.

Step 2: laser with wavelength of 532nm emitted by a first YAG laser 1 passes through a first spectroscope 15, then passes through a sheet light system 16, is converted into a beam of laser sheet light, and is irradiated into an optical engine 5 and vertically irradiated on combustion flame, and then passes through a first spectroscope 6, and is filtered by a 450nm band-pass filter 7, and then is filtered by a first ICCD camera 8 to obtain an excited laser-induced blazing light signal, so that the carbon smoke spatial distribution is measured under the combustion condition;

and step 3: laser with the wavelength of 355nm emitted by the second YAG laser 4 passes through the first spectroscope 15 and then passes through the sheet light system 16 to be converted into a beam of laser sheet light, then the laser sheet light is emitted into the optical engine 5 and vertically irradiated on fuel oil spray flame, then the laser sheet light passes through the first spectroscope 6 and a 410nm band-pass filter 9, and finally a laser induced fluorescence signal is obtained by the second ICCD camera 10, so that the measurement of the soot precursor product PAH base is realized.

Preferably, the shooting gate widths of the first ICCD camera 8 and the second ICCD camera 10 are set to 200ns and 20ns respectively to adapt to the radiation intensity of PAH radicals and soot, so as to ensure the accuracy of the timing and duration of signal capture.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.