JP4955524B2 - 方法 Methods to reduce primary particle emissions - Google Patents

Description

  The present invention relates to a technique for reducing soot generated by combustion of carbon-containing materials, and more particularly to a technique for suppressing generation of soot generated from an internal combustion engine.

  In diffusion combustion, which is widely applied in industry, generation of soot is regarded as a problem. In particular, there is a demand for reducing the amount of soot contained in exhaust gas to the atmosphere in terms of adverse effects on the environment. In diesel automobiles, filters (DPF) for collecting soot in exhaust gas are widely used. However, the weight increase due to the installation of the DPF, and the cost burden for the replacement and regeneration of the DPF itself or the DPF are unavoidable.

  By the way, since soot is easily generated in a region where carbon density is partially high and oxygen is insufficient in a combustion environment, measures for improving the mixing efficiency of fuel and air have been devised. Such countermeasures include the use of fuel that evaporates easily and mixes with air, promotes fuel evaporation and mixing with air by intentionally creating turbulence in the combustion chamber, For example, the fuel is injected into the combustion chamber at a high pressure of 1000 atm or higher.

  However, no matter how excellent liquid fuel is used, soot generation cannot be sufficiently prevented under excessive fuel conditions, there is a limit to improvement of mixing efficiency due to turbulent flow, and increase in spray pressure is also cost, There are restrictions from the point of increase in weight and strength of the pressure-resistant member.

  In addition, a technique for promoting the evaporation of fuel by heating the fuel before injection has been developed. For example, Patent Documents 1 and 2 disclose a technique for irradiating a fuel tank with microwaves and injecting a preheated fuel into a combustion chamber.

  However, even with such a technique, the fuel vaporization rate is improved, but it is still insufficient to reduce soot generation.

Therefore, Patent Document 3 discloses a technique for irradiating microwaves into a combustion chamber after fuel injection. According to this technique, plasma discharge is generated in the combustion chamber by microwave irradiation, and the radical concentration in the combustion chamber increases, so that the radicals easily collide with the soot particles. Thereby, dissociation of the carbon bond of the soot is promoted and soot can be reduced.
JP-A-2005-340108 JP 2007-239653 A JP 2007-113570 A

  However, since the technique disclosed in Patent Document 3 is a system that uses plasma discharge, it is generally difficult to maintain the plasma state, and it is also difficult to control the collision between radicals and soot particles. Moreover, in order to generate plasma discharge, generally a great deal of energy, special equipment and inert gas are required.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method and an internal combustion engine that can improve the efficiency of reducing soot generated by fuel combustion with simple control and means.

  The present inventors have found that the nucleation of soot nuclei and the surface growth of nuclei are inhibited by irradiating the burning fuel with microwaves under non-plasma generation conditions, and the present invention has been completed. Specifically, the present invention provides the following.

  (1) A method of reducing the emission of primary particles by burning a fuel containing carbon and irradiating the burning fuel with microwaves under non-plasma generation conditions.

  (2) A method of reducing the particle size of the discharged primary particles by burning a fuel containing carbon and irradiating the burning fuel with microwaves under non-plasma generation conditions.

  (3) A method for improving the crystallinity of discharged primary particles by burning a fuel containing carbon and irradiating the burning fuel with microwaves under non-plasma generation conditions.

(4) An internal combustion engine comprising a combustion chamber in which fuel is combusted, introduction means for introducing liquid or gaseous fuel and oxidant into the combustion chamber, and microwave irradiation means for irradiating the combustion chamber with microwaves Because
The microwave irradiation means irradiates the burning fuel with microwaves under non-plasma generation conditions,
An internal combustion engine in which the particle size of the discharged primary particles is reduced.

  (5) The internal combustion engine according to (4), wherein the non-plasma generation condition is a condition in which the crystallinity of the discharged primary particles is improved.

  (6) The internal combustion engine according to (4) or (5), wherein the microwave irradiation means irradiates single mode or multimode microwave.

(7) further comprising a control means for controlling the microwave irradiation means,
The internal combustion engine according to any one of (4) to (6), wherein the control means includes stop control means for stopping microwave irradiation by the microwave irradiation means when the fuel is not burned.

  (8) The control means further includes a condition adjusting means for increasing or decreasing one or more selected from the group consisting of a microwave frequency and an output in accordance with an increase or decrease in the air-fuel ratio in the combustion chamber. Internal combustion engine.

  According to the present invention, since the burning fuel is irradiated with microwaves under non-plasma generation conditions, soot nucleation and growth of the nuclear surface are inhibited. Thereby, the reduction efficiency of the soot generated from fuel combustion can be improved. In addition, since such an effect can be obtained without generating plasma, control of combustion and microwave irradiation can be simplified, and special means necessary for plasma generation can be reduced.

  Hereinafter, although an embodiment of the present invention is described, the present invention is not limited to this.

<How to reduce wrinkles>
The method according to the present invention includes a procedure of burning a fuel containing carbon and irradiating the burning fuel with microwaves under non-plasma generation conditions. The “plasma non-generation condition” in this specification refers to a condition that is theoretically expected that the combustion field irradiated with microwaves is not substantially converted to plasma, and until no plasma is actually generated in the combustion field. Is not a requirement.

  The fuel used may be solid, liquid, or gas, but is preferably liquid or gaseous fuel. Here, the liquid or gaseous fuel includes various liquids or gases containing carbon such as gasoline and light oil, but excludes solid fuel such as garbage.

  In order to explain the principle of the method of the present invention, an example of the soot generation process is shown in FIG. In the high temperature oxidation process, the hydrocarbon compound becomes C3H3 after being converted to acetylene (C2H2). Since the oxidation rate of C3H3 is slow, C6H6 (benzene) is easily synthesized by binding to each other. When benzene is bonded to each other, various polycyclic aromatic carbons (PAH) are generated, and nuclei are formed by accumulating these PAHs. Thereafter, as the degree of carbon supersaturation decreases, surface growth in which carbon is sequentially bonded to the surface of the formed nuclei becomes more dominant than formation of new nuclei, and primary particles are formed. When the degree of carbon supersaturation further decreases over time, surface growth stops, and primary particles aggregate due to intermolecular forces or the like to form wrinkles.

  Here, in order to solidify a liquid or gaseous substance, nucleation is required, but nucleation is activated in a highly supersaturated environment. Nucleation proceeds with a balance between a decrease in free energy proportional to the volume of the nuclear precursor and an increase in free energy proportional to the surface area of the nuclear precursor. That is, as the particle size of the nuclear precursor increases, the free energy decreases, so that a stable nucleus is transferred.

  In the method of the present invention, since the microwave is irradiated under the non-plasma generation condition in this process, the temperature of the nuclear precursor is increased. Thereby, the thermal frequency of the molecule | numerator and atom which comprise a nuclear precursor increases, and the probability that it will detach | leave from a nuclear precursor increases. As a result, it is estimated that nucleation is inhibited.

  In addition, microwaves are also irradiated to the nuclei in the process of surface growth under non-plasma generation conditions, and as a result of the temperature of the nuclei increasing, the critical radius of the nuclei increases. As a result, it is presumed that nuclei that could exist stably at low temperatures also become unstable and easily disappear as the critical radius increases. In other words, it can be said that the nuclei remaining through the method of the present invention have a larger particle size than the nuclei produced without the method of the present invention, and the number of nuclei themselves decreases. The critical radius refers to the radius of a nucleus that can exist stably at a temperature under a certain condition.

  By the way, the supersaturation degree increases at low temperatures, and the diffusion of atoms on the solid surface and the detachment of atoms from the solid do not easily occur. Therefore, the crystallinity decreases, and when the supersaturation degree further increases, the solid becomes amorphous.

  However, in the method of the present invention, since the solid is heated and the supersaturation degree is lowered by irradiation with microwave non-plasma generation conditions, atoms adhering to the solid surface diffuse on the solid surface and stabilize kink and the like. The probability of detaching atoms from the crystal surface increases with crystallization at any location. As described above, according to the method of the present invention, the surface growth rate of the primary particles is lowered, and this phenomenon appears as a result of improvement in crystallinity and reduction of the particle size of the primary particles.

  結晶 The crystallinity of primary particles is not particularly limited, but can be evaluated by appropriately combining conventionally known surface analysis methods such as SEM, TEM, X-ray diffraction, AFM, XPS, AES, FTIR, laser Raman spectroscopy, etc. Good. Further, the particle size of the primary particles is not particularly limited, but may be calculated based on a laser induced red heat method (LII), and may be an average particle size calculated from, for example, a particle size distribution.

  The microwave generation conditions used in the method of the present invention are not particularly limited as long as the irradiated combustion field is not a plasma generation condition in which plasma is not generated, but the temperature of the irradiated soot rises to generate primary particles. The amount may be appropriately set so as to reduce the amount, and specifically, the temperature of the soot being generated is set to increase by about 50K or more. In addition, the “non-plasma condition” may be set as appropriate so that the particle size of the discharged primary particles is reduced or the crystallinity is improved. Microwave conditions can be adjusted by output (power) and frequency.

  The temperature rise by the microwave is mainly induction heating due to Joule loss caused by movement of free electrons in a molecule to be irradiated by a high frequency electric field. It is known that the wavelength causing the temperature rise due to the Joule loss is generally in a wide range, but the wavelength of the microwave used in the present invention is 1 MHz to several hundred GHz in consideration of the temperature rise rate of the soot. Is preferred. Moreover, less than 10 GHz is more preferable at the point which can reduce required energy, and about 2.45 GHz is still more preferable at the point which can utilize a commercially available microwave generator.

  The means for irradiating such a microwave is not particularly limited, and may be a conventionally known one. The introduction of the microwave may be performed by appropriately using various means such as a waveguide or a coaxial cable, and the spatial mode of the microwave may be either single mode or multimode. In addition, it is preferable to irradiate the microwave only to a necessary portion in the single mode from the viewpoint that the necessary energy can be reduced.

  Further, the microwave irradiation may be performed before the combustion in addition to the combustion of the fuel. Thereby, when the fuel is liquid, the evaporation of the fuel is promoted, and the mixing efficiency of the fuel and the oxidant (for example, oxygen) is improved. As a result, since the oxidation of molecules in the fuel proceeds, the amount of soot generated can be reduced synergistically.

  As explained above, primary particle formation (nucleation rate and surface growth rate) depends on the degree of supersaturation (carbon concentration and temperature) of carbon atoms and carbon molecules around the nucleus precursor or around the nucleus, while molecular The rate of oxidation (which affects the inhibition of soot formation) depends on the oxygen concentration around the carbon and the temperature. Therefore, it is possible to control the frequency and / or output of the microwave based on the fluctuation of the oxidizer / fuel ratio in the combustion environment so that the generation of soot can be inhibited with the minimum necessary energy in various combustion environments. preferable. Specifically, the microwave frequency and / or output may be decreased in accordance with the increase in the oxidizer / fuel ratio, and the microwave frequency and / or output may be increased in accordance with the decrease in the oxidizer / fuel ratio. .

  It is also preferable to control the frequency and / or output of the microwave based on the fluctuation of the temperature of the combustion environment. Specifically, the frequency and / or output of the microwave is decreased as the temperature increases, and the temperature What is necessary is just to increase the frequency and / or output of a microwave according to the fall of this.

  As described above, the method of the present invention is not a system that uses plasma generation, but is a system that simply uses inhibition of soot generation due to temperature rise of soot, so that the complexity of control can be reduced. Further, since the microwave irradiation can be performed with a simple device, cost reduction can be realized. In addition, since the generation efficiency of microwaves is high, not only is it necessary to use a small amount of energy, it is economical, but also it can be generated in a very short time of about microseconds, so that high-speed intermittent irradiation can be performed. . For this reason, continuous irradiation may not be performed and microwave irradiation may be stopped when the fuel is not burned, thereby further reducing the required energy. Moreover, since microwave irradiation can be easily performed at both normal pressure and high pressure, it can be used for any application.

<Internal combustion engine>
The internal combustion engine according to the present invention is an application of the aforementioned soot reduction method. A diesel engine 10 as an internal combustion engine shown in FIG. 2 includes a combustion chamber 20 in which fuel is combusted. The combustion chamber 20 is provided with an air introduction portion 30 and a fuel introduction portion 40 as introduction means, and air containing oxygen gas as an oxidant is introduced from the air introduction portion 30 and liquid from the fuel introduction portion 40. Light oil as fuel is injected.

  A piston (not shown) is provided inside the combustion chamber 20, and the internal pressure of the combustion chamber 20 increases and decreases as the piston moves. Specifically, after air is introduced from the air introduction part 30 into the combustion chamber 20, the piston narrows the internal space of the combustion chamber 20 and increases the internal pressure of the combustion chamber 20. When light oil is injected from the fuel introduction part 40 in this state, the light oil ignites and starts combustion.

  Here, the diesel engine 10 further includes a microwave introduction unit 50 as microwave introduction means. The microwave introduction unit 50 includes a microwave generation unit 51 such as a magnetron, and the microwave generated by the microwave generation unit 51 is combusted via a microwave transmission unit 53 such as a waveguide or a coaxial cable. The burning fuel in the chamber 20 is irradiated. Thereby, the generation of soot is suppressed by the above-described mechanism without substantially generating plasma in the combustion field. It is preferable that the microwave transmission part 53 is arrange | positioned so that the irradiated microwave may be irradiated to the fuel under combustion intensively.

  The microwave introduced by the microwave introduction unit 50 may be either single mode or multimode. In addition, it is preferable to irradiate only the required location in the single mode, and it is preferable to irradiate the location where the fuel during combustion is concentrated, from the viewpoint that the required energy can be reduced.

  The generation condition of the microwave generated by the microwave generation unit 51 is not particularly limited as long as the irradiated combustion field is not a plasma generation condition in which the irradiation field is not converted into plasma, but the temperature of the irradiated soot is increased to generate primary particles. The amount may be appropriately set so as to reduce the amount, and specifically, the temperature of the soot being generated is set to increase by about 50K or more. In addition, the “non-plasma condition” may be set as appropriate so that the particle size of the discharged primary particles is reduced or the crystallinity is improved. Microwave conditions can be adjusted by output (power) and frequency.

  Moreover, it is preferable that the wavelength of the microwave which the microwave generation part 51 generate | occur | produces is 1 MHz-several hundred GHz in consideration of the temperature increase rate of the irradiated soot. Less than 10 GHz is more preferable at the point which can reduce required energy. If a commercially available microwave generator is used as the microwave generator 51, the wavelength of the microwave is generally about 2.45 GHz.

  The gas expanded by the combustion moves through the piston and is discharged from the discharge unit 60 to the outside of the diesel engine 10, and then subjected to a purification process such as DPF passage if necessary, and then discharged to the atmosphere as exhaust gas. The Since the generation of soot is suppressed, the amount of soot contained in the exhaust gas is reduced. In addition, since the amount of soot has already been reduced when it is released to the outside of the diesel engine 10, the required DPF can be reduced in size or weight, and the frequency of replacement and regeneration of the DPF can be reduced. Thereby, both initial cost and maintenance cost can be significantly reduced. Further, in the piston engine as in this embodiment, it is not necessary to continuously irradiate microwaves, and it is sufficient to perform intermittent irradiation only at the time of combustion, so that power consumption can be greatly reduced.

  Then, it returns to the introduction of air from the air introduction part 30 again, and the above event is repeated. In addition, the movement of the piston according to the increase / decrease in the volume inside the combustion chamber 20 acts on the outside world and becomes a driving force of the vehicle or the like.

  The diesel engine 10 according to the present embodiment further includes a control device 70 that controls the microwave generator 51. As shown in FIG. 3, the control device 70 includes a stop control unit 71 as a stop control unit and a condition adjustment unit 73 as a condition adjustment unit.

  When the fuel in the combustion chamber 20 is not combusted, the stop control unit 71 performs control to stop the microwave irradiation by the microwave generation unit 51. The timing when the fuel is not burned can be estimated based on the composition of the fuel, the temperature and pressure in the combustion chamber 20, and can be easily estimated based on the position of the piston.

  The condition adjusting unit 73 receives information related to the amount of air introduced from the air introduction unit 30 and receives information related to the amount of light oil introduced from the fuel introduction unit 40. Based on these pieces of information, the air-fuel ratio in the combustion chamber 20 is calculated, and the frequency and / or output of the microwave generated from the microwave generator 51 is increased or decreased in accordance with the increase or decrease in the calculated value. As a result, the generation of soot can be sufficiently suppressed with the minimum necessary energy even in an environment of any air-fuel ratio that fluctuates frequently. In addition, the transmission source of information is not restricted to the air introduction part 30 and the fuel introduction part 40, You may set suitably.

  More preferably, a temperature detection unit that detects the temperature in the combustion chamber 20 is provided, and the condition adjustment unit 73 changes the frequency and / or output of the microwave according to the increase or decrease of the detection value received from the temperature detection unit. Decrease. Thereby, generation | occurrence | production of soot can be suppressed more fully with a required minimum energy.

  First, the apparatus used in the examples will be described. As shown in FIG. 4, the apparatus 100 includes a reactor 120 having an internal size of 300 mm × 300 mm × 300 mm, and the reactor 120 is provided with a hollow air supply unit 130, a fuel introduction unit 140, and a discharge unit 160. ing. A penetration portion of the air supply unit 130 and the fuel introduction unit 140 is covered with a radio wave shielding member 125 to prevent leakage of microwaves from the microwave introduction unit 150.

FIG. 5 is a partially enlarged view of the air supply unit 130 and the fuel introduction unit 140. As shown in FIG. 5, the air supply unit 130 and the fuel introduction unit 140 are arranged such that their tips face each other with a slight gap C therebetween. A large number of open-ended tubes “DEGUSITIT” (manufactured by FRIATEC) made of high-purity oxide ceramics are bundled and inserted into the air supply unit 130 and the fuel introduction unit 140. When the tubes were bundled, an inorganic adhesive “ThreeBond 3732” (manufactured by Three Bond Co., Ltd.) having a heat resistant temperature of 1400 ° C. was used. As a result, the gas introduced from the air supply unit 130 and the fuel introduction unit 140 is rectified and then introduced into the gap C. In addition, the dimension of each member is as follows.
Air supply unit 130, fuel introduction unit 140: inner diameter 29 mm
Clearance C: 13.5mm
Both ends open tubes 135 and 145: inner diameter 2 mm, outer diameter 3 mm, length 25 mm

  The reactor 120 is provided with a waveguide 153 at the same height as the gap C. The waveguide 153 communicates with the magnetron 151 and can irradiate the gap C with the microwave generated by the magnetron 151. The waveguide 153 was designed so that a microwave having a frequency of 2.45 GHz can be generated in the multi-mode in the reactor 120 having the above-described dimensions. As the magnetron 151, a magnetron whose output can be adjusted at 0 to 780 W was used.

[Test Example 1]
Using the apparatus 100 described above, the following test was performed. Air is supplied from the air supply unit 130 at a flow rate of 1.3 L / min, and air-fuel mixture (nitrogen gas 1.15 L / min, C2H2 gas 0.2 L / min) is supplied from the fuel introduction unit 140 at 1.35 L / min. did. The gas introduced into the gap C was ignited and irradiated with microwaves having a frequency of 2.45 GHz toward the burning fuel (700 W). An image of the diffusion flame generated in the gap C at this time is shown in FIG. 6 together with an image in the case of no microwave irradiation.

  As shown in FIG. 6, it was observed that the brightness of the bright flame was increased by irradiating the burning fuel with microwaves. Since the bright flame is emission of particulate matter such as soot, it was found that the soot particles were heated by microwave irradiation.

[Test Example 2]
Next, the volume fraction of the soot occupying the flame of the gap C was measured using a laser induced red heat method (LII). Specifically, a pulse Nd ³⁺ : YAG laser “LQ129” (manufactured by SolarLaserSystems) is used, and a second harmonic (532 nm) laser (output 0.15 to 0.19 J / cm ² ) is applied to the gap of the apparatus 100. C diffusion flame was irradiated. Laser irradiation was performed for each case where the output of the microwave generated by the magnetron 151 was 175 W, 350 W, 525 W, and 700 W.

When the laser is irradiated, the soot in the flame is heated to about 4000 K and generates incandescent light (FIG. 8). In this test, incandescent light generated on the nozzle side (middle) and blue flame side (edge) of the diffusion flame was measured. Specifically, as shown in FIG. 7, the generated incandescent light was passed through a dichroic filter and a lens to remove scattered light having a wavelength of 532 nm, and then divided into two optical paths by a half mirror. The light introduced into each optical path passes through an interference filter (center wavelength: 410 nm, 670 nm) and then enters a photomultiplier tube “H7732-10” (manufactured by Hamamatsu Photonics). The output signal from the photomultiplier tube was observed with a high-speed sampling oscilloscope “TDS3052B” (manufactured by Tektronix). Based on the following formula, the volume fraction of cocoons was calculated using the observed values. Further, the temperature of the extended flame was also measured by the LII two-wavelength two-color method as described above.
LIIe (λλ): detection signal w: laser beam width λ: interference filter center wavelength E (m): absorption coefficient of soot

  FIG. 9 shows the relationship between the microwave output and the soot volume fraction, FIG. 10 shows the relationship between the microwave output and the soot primary particle size, and FIG. 11 shows the relationship between the microwave output and the soot temperature. As shown in FIG. 9, by irradiating the microwave, the volume fraction of the soot rapidly decreases on both the nozzle side and the blue flame side. It was confirmed that the output depends to some extent. Also, as shown in FIG. 10, by irradiating microwaves, the particle size of the primary particles is reduced on both the nozzle side and the blue flame side, and the degree of particle size reduction depends on the output of the microwave. It was confirmed that it depends to some extent. According to FIG. 11, the temperature of the soot increases as the output of the microwave increases, so it is estimated that the reduction in the volume fraction of soot and the primary particle size of the soot is due to the temperature rise of the soot. It was.

[Test Example 3]
A ceramic rod having a diameter of 1 mm or less was brought close to the diffusion flame in Test Example 1 to deposit soot on the surface of the rod, and this soot was observed with an electron microscope. FIG. 12 shows an SEM image and a TEM image in the control group (non-microwave irradiation), and FIG. 13 shows an SEM image and a TEM image in the microwave irradiation group.

  In the control group, it was observed that the primary particles of the camellia were uniformly uniform in color (for example, region γ) and were in an amorphous state. On the other hand, in the microwave irradiation section, it was observed that the color was dark from the surface of the primary particles of the cocoon toward the center, and the primary particles had high crystallinity. Thereby, it was confirmed that the crystallinity of the primary particles is improved by irradiating the burning fuel with microwaves. Note that although the region β in FIGS. 12 and 13 appears dark, this is due to simple superposition of primary particles and does not reflect crystallinity.

  FIG. 14 is a ΦT map in a conventional diesel engine that does not irradiate microwaves (for example, “Motor fan separate volume special feature diesel new era”, page 79). The ΦT map is an equivalent ratio Φ (amount obtained by dividing the fuel / air value by the stoichiometric fuel st / air st) and the combustion temperature. It is a map produced based on a detection amount. As confirmed in Test Example 2, FIG. 15 shows a ΦT map when it is assumed that when the microwave is irradiated at 700 W, the soot temperature is increased by about 1000 K, and the soot temperature is increased by about 1000 K.

  As shown in FIG. 15, the soot temperature is raised by about 1000K by irradiating microwaves even at an equivalent ratio that originally generates soot due to a shortage of the combustion temperature. The As a result, a condition where neither soot nor NOx occurs is newly created (in FIG. 15, the region α surrounded by a dotted line), the degree of freedom of combustion control can be expanded, and the output in a state in which soot generation is suppressed. Improvement in fuel consumption is also expected. In addition, the production cost can be reduced by simplifying the combustion control.

<Modification>
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  For example, in the above-described embodiment, a diesel engine is employed as the internal combustion engine. However, the present invention is not limited thereto, and may be a gas turbine engine, a jet engine, a direct injection gasoline engine, or the like. Depending on the type of the internal combustion engine, the configuration and arrangement of the introduction means and the microwave irradiation means may be set as appropriate.

It is a figure explaining the generation | occurrence | production process of a soot. 1 is a schematic configuration diagram of an internal combustion engine according to an embodiment of the present invention. It is a block diagram of the control means which comprises the internal combustion engine which concerns on the said embodiment. It is a schematic block diagram of the apparatus used in one Example of this invention. FIG. 4 is a partially enlarged view of FIG. 3. It is a photograph which shows the temperature rise of the soot by microwave irradiation. It is a block diagram of the measurement system used for the test example of this invention. It is a photograph which shows the measurement conditions of the test example of this invention. It is a graph which shows the relationship between a microwave output and a housing volume fraction. It is a graph which shows the relationship between a microwave output and a soot primary particle diameter. It is a graph which shows the relationship between a microwave output and soot temperature. It is the SEM image and TEM image of the soot primary particle produced | generated on the conditions of microwave non-irradiation. It is the SEM image and TEM image of the soot primary particle produced | generated on the conditions of microwave irradiation. It is a ΦT map in a microwave non-irradiated internal combustion engine. It is a ΦT map in an internal combustion engine of a microwave irradiation system.

Explanation of symbols

10 Diesel engine (internal combustion engine)
20 Combustion chamber 30 Air introduction part (introduction means)
40 Fuel introduction part (introduction means)
50 Microwave introduction part (microwave introduction means)
70 Control device (control means)
71 Stop control unit (stop control means)
73 Condition adjustment unit (condition adjustment means)

Claims (8)

Combustion of carbon-containing fuel, microwaves with a frequency of 1 MHz to several hundred GHz are applied to the burning fuel so that the burning combustion field is not converted into plasma and the temperature of the soot being generated rises by about 50K or more. A method of reducing the discharge of primary particles by irradiation. Combustion of carbon-containing fuel, microwaves with a frequency of 1 MHz to several hundred GHz are applied to the burning fuel so that the burning combustion field is not converted into plasma and the temperature of the soot being generated rises by about 50K or more. A method of reducing the particle size of the discharged soot primary particles by irradiation. Combustion of carbon-containing fuel, microwaves with a frequency of 1 MHz to several hundred GHz are applied to the burning fuel so that the burning combustion field is not converted into plasma and the temperature of the soot being generated rises by about 50K or more. A method of improving the crystallinity of the discharged soot primary particles by irradiation. An internal combustion engine comprising: a combustion chamber in which fuel is combusted; introduction means for introducing liquid or gaseous fuel and oxidant into the combustion chamber; and microwave irradiation means for irradiating microwaves into the combustion chamber. ,
The microwave irradiation means irradiates the burning fuel with microwaves having a frequency of 1 MHz to several hundreds of GHz so that the irradiated combustion field is not converted into plasma and the temperature of the soot being generated rises by about 50K or more. ,
An internal combustion engine in which the particle size of the discharged primary particles is reduced. The microwave irradiation means irradiates the burning fuel with microwaves having a frequency of 1 MHz to several hundreds of GHz so that the irradiated combustion field is not converted into plasma and the temperature of the soot being generated rises by about 50K or more. ,
請 Motomeko 4 internal combustion engine according crystallinity you improve soot primary particles discharged.   The internal combustion engine according to claim 4 or 5, wherein the microwave irradiation means irradiates single mode or multimode microwave. A control means for controlling the microwave irradiation means;
The internal combustion engine according to any one of claims 4 to 6, wherein the control means includes stop control means for stopping the microwave irradiation by the microwave irradiation means when the fuel is not burned.   8. The internal combustion engine according to claim 7, wherein the control means further includes a condition adjusting means for decreasing one or more selected from the group consisting of a frequency and an output of microwaves in accordance with an increase / decrease in the air / fuel ratio in the combustion chamber.