JP7205986B2 - fuel burner - Google Patents

Description

The present invention relates to a fuel combustion device. More specifically, it relates to a combustion apparatus for flame-retardant fuel such as ammonia.

With the increasing demand for reducing carbon dioxide emissions, expectations are rising for ammonia as a fuel to replace carbon-based fuels. Ammonia does not contain carbon, so it does not emit carbon dioxide when burned. Ammonia is already widely used as a fertilizer, is inexpensive, and can be stably supplied. Ammonia has a liquefying pressure equivalent to that of LPG and can be stored as a liquid at room temperature. Ammonia has many advantages as an alternative fuel to carbon-based fuels.

On the other hand, ammonia is flame retardant. While the ignition energy of carbonaceous fuel is about 80 mJ to 120 mJ, ammonia requires ignition energy of about 400 mJ to 600 mJ. Further, the laminar combustion speed of ammonia is about seven times slower than that of carbonaceous fuel. A study on an internal combustion engine using this flame-retardant ammonia as fuel is reported in Japanese Patent Laid-Open No. 2010-159705.

Japanese Unexamined Patent Application Publication No. 2010-159705

However, when burning flame-retardant fuels such as ammonia fuels, compared to burning carbon-based fuels that are widely used today, there are difficulties in initial ignition, difficulty in stabilizing combustion, etc. Many challenges remain. In particular, in order to put combustion devices using flame-retardant fuel into practical use in various fields, it is important to maintain stable combustion.

SUMMARY OF THE INVENTION An object of the present invention is to provide a combustion apparatus capable of stably continuing combustion of flame-retardant fuel.

A fuel combustion apparatus according to the present invention includes a combustion cylinder, a fuel injector for feeding a mixed gas fuel into the combustion cylinder as a swirling flow, an igniter having an ignition part in the combustion cylinder, and and a controller capable of adjusting the mixture ratio of the mixed gas fuel according to the detection result of the ion detector.

Preferably, said fuel is ammonia.

Preferably, the detection section is positioned near the ignition section. The detection section may be shared with the ignition section.

Preferably, the ignition section includes a discharge electrode and a first ground electrode, the detection section includes an application electrode and a second ground electrode, and the first ground electrode and the second ground electrode are common. .

Preferably, the ignition part is located in a region where the mixed gas fuel stays in the combustion cylinder.

Preferably, the combustion cylinder has a cylindrical body and a lower lid covering the end of the body, and the lower lid is provided with an inlet for feeding the mixed gas fuel. , the ignition section and the detection section are arranged in the lower lid section.

Preferably, the detection section is arranged on the lower lid section and the body section.

Preferably, the inlet has an annular shape, and the igniter and the detector are arranged in a region of the lower cover surrounded by the inlet.

The inlet may have a circular shape, and the ignition section and the detection section may be arranged around the inlet in the lower lid section.

One or a plurality of the ignition parts are present, and at least one of the ignition parts is positioned in a region in which the mixed gas fuel does not stay in the combustion cylinder.

Preferably, the ignition part is arranged in the lower lid part and the body part.

A fuel combustion method according to the present invention comprises a combustion step of continuously burning fuel. In the combustion step, the mixed gas fuel containing the fuel is ignited while sending it into the combustion cylinder as a whirling current, the ions generated by this combustion are detected, and the mixture ratio of the fuel is determined based on the detection result. adjust.

Preferably, the combustion method further comprises, prior to the combustion step, measuring a correlation between a parameter representing the combustion state of the fuel and the ion detection result to set a reference range for the ion detection result. In adjusting the mixture ratio of the fuel, the ion detection result is adjusted to fall within the reference range.

Preferably, the parameters representing the state of combustion of the fuel include emissions of oxides during combustion.

In the fuel combustion apparatus according to the present invention, since the ion current detector is arranged in the combustion cylinder, it is possible to grasp the combustion state of the mixed gas fuel introduced into the combustion cylinder. In addition, since the device is also provided with a controller for adjusting the air-fuel ratio of the mixed gas fuel, it is possible to perform appropriate air-fuel ratio control based on the grasped combustion state.

In this combustion device, since the mixed gas fuel is sent into the combustion cylinder as a swirling airflow, a swirl-like "region where the mixed gas stagnates" is generated in the combustion cylinder, where the flow is slower than the main stream of the swirling airflow. When an igniter and an ion detector are arranged in this retention region, the combustion state of the region to which energy is effectively supplied is reflected in the ion current in this combustion apparatus, so that the state of the flame kernel can be grasped. It becomes possible. In addition, since the apparatus includes a controller for adjusting the air-fuel ratio of the mixed gas fuel, air-fuel ratio control based on the state of the flame kernel can be achieved.

In addition, when the igniter and the ion detector are arranged in a region away from the retention region, the combustion state of the region flowing at a relatively high speed is reflected in the ion current in this combustion device. can be grasped. Moreover, since the apparatus includes a controller for adjusting the air-fuel ratio of the mixed gas fuel, it is possible to realize air-fuel ratio control that contributes to stabilization of combustion.

FIG. 1 is a conceptual diagram showing a combustion device according to one embodiment of the present invention. 2 is a top view of part of the combustion apparatus of FIG. 1. FIG. 3 is a connection diagram showing a part of the combustion apparatus of FIG. 1. FIG. 4 is a circuit diagram showing an example of an ion detection circuit of the combustion apparatus of FIG. 1; FIG. FIG. 5 is a graph showing the relationship between the mixture ratio, the ion current, and the amount of oxide emissions when fuel is burned in the combustion apparatus of FIG. FIG. 6 is a graph showing the relationship between the flow rate of fuel and the ion current when fuel is burned in the combustion apparatus of FIG. FIG. 7 is a conceptual diagram showing a combustion device according to another embodiment of the invention. FIG. 8 is a top view of part of a combustion apparatus according to still another embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

FIG. 1 is a conceptual diagram showing a fuel combustion device 2 according to one embodiment of the present invention. In this figure, part of the device is shown in cross section. This combustion device 2 includes a combustion cylinder 4 , a fuel injector 6 , a fuel mixer 8 , an igniter 10 , an ion detector 12 and a controller 14 . In this specification, the direction indicated by arrow X in FIG. The direction in which the fuel injector 6 is positioned is downward.

The combustion cylinder 4 has a tubular shape. In this embodiment, the combustion can 4 is cylindrical. In FIG. 1, the combustion tube 4 is shown in cross section. The combustion cylinder 4 includes a body portion 16 , a lower lid portion 18 and an upper lid portion 20 . The barrel 16 forms the side surface of the combustion tube 4 . The body portion 16 extends vertically. The lower lid portion 18 covers the lower end of the body portion 16 . An inlet 22 is provided in the lower lid portion 18 . A mixed gas containing fuel (mixed gas fuel) is sent from this inlet 22 . FIG. 2 is a view of the lower lid portion 18 viewed from above. As shown, in this embodiment the inlet 22 presents an annular shape. The upper lid portion 20 covers the upper end of the body portion 16 . An output port 23 is provided in the center of the upper lid portion 20 from which flames are ejected. In this embodiment, the material of the combustion tube 4 is heat-resistant glass.

As shown in FIG. 1 , the fuel injector 6 is positioned below the lower lid portion 18 of the combustion cylinder 4 . The fuel injector 6 has a housing 24 and a swirler 26 . The housing 24 has an annular shape when viewed from below. The inside of the housing 24 is hollow. A swirler 26 is located inside the housing 24 . The swirler 26 is positioned below the inlet 22 . In FIG. 2, the swirler 26 located underneath is visible through the inlet 22 . The swirler 26 comprises a plurality of slanted vanes. The mixed gas fuel fed into the housing 24 passes through the swirler 26 and becomes an airflow (swirling airflow) accompanied by a rotating vortex (swirl flow). The mixed gas fuel is sent into the combustion cylinder 4 as a swirling airflow. The swirler 26 material is typically steel.

Although not shown, the fuel injector 6 may further include a drive for rotating the swirler 26 . By rotating the swirler 26, the mixed gas fuel may be sent into the combustion tube 4 as a swirling airflow.

The fuel mixer 8 has a fuel tank 28 and a valve 30 . In this embodiment, the fuel mixer 8 has a first valve 30a and a second valve 30b. A fuel tank 28 stores flame-retardant fuel, which is the main fuel of the combustion device 2 . In this embodiment, the fuel tank 28 stores liquefied ammonia. This liquefied ammonia is vaporized and sent to the fuel injector 6 . A first valve 30 a is connected to the fuel tank 28 . A first valve 30a regulates the amount of fuel in the fuel mixture. A second valve 30b regulates the amount of air in the fuel mixture.

The fuel mixer 8 may further include a fuel tank containing secondary fuel and a third valve connected thereto. At this time, the fuel mixer 8 mixes two types of fuel and air. This secondary fuel has higher combustibility than the primary fuel. That is, the ignition energy of the secondary fuel is smaller than the ignition energy of the primary fuel, and the laminar burning velocity of the secondary fuel is greater than the laminar burning velocity of the primary fuel. Mixing the secondary fuel with high combustibility facilitates ignition of the mixed gas fuel. Methane is exemplified as a typical secondary fuel. The combustion device 2 may have three or more fuel tanks.

FIG. 3 is a connection diagram showing the connections of the igniter 10, the ion detector 12 and the controller 14. FIG.

The igniter 10 ignites the gaseous fuel mixture. As shown in FIG. 3, the igniter 10 includes an ignition section 32 and a voltage generation section. FIG. 1 shows the ignition section 32 among them. In FIG. 1, two igniters 32 are shown.

The ignition part 32 is arranged in "a region where mixed gas fuel stays". In FIG. 1, arrows indicate the swirl flow of the mixed gas fuel. The main stream of the swirling airflow (thick dotted line in FIG. 2) flowing from the inlet 22 spreads along the inner peripheral surface of the combustion tube 4 and advances upward while swirling. Since the atmospheric pressure is low in the portion where this main stream flows, the mixed gas fuel in the central portion of the combustion tube 4 is pulled by this flow. A vortex flow (thin dotted line in FIG. 2) is generated in the central portion. The area where this swirling flow occurs is the "area where the mixed gas fuel stays (stagnation area)". In this retention region, an air current whose speed is lower than that of the main stream of swirling air current flows continuously. In this portion, the mixed gas fuel is swirled and flows from below to above at a slower speed than the main stream of the swirling air flow as a whole. In the retention area, the mixed gas fuel forms a swirling flow, so the mixed gas fuel is repeatedly led to the ignition section 32 . The mixed gas fuel repeatedly passes through the vicinity of the ignition section 32 .

A typical retention area is near 39 a of area 38 of lower lid 18 surrounded by annular inlet 22 . Similarly, the outer vicinity 39b of the inlet 22 is also a retention area. As shown in FIG. 1, at the center of the combustion tube 4 in the vertical direction, there is also a stagnation area on the inside 39c of the main stream. These stagnant regions can be investigated, for example, by injecting colored smoke into the combustion canister 4 at the same velocity as the gaseous fuel mixture. The retention area can also be examined by simulation.

In this embodiment, the ignition portion 32 is located on the lower lid portion 18 . The ignition part 32 is positioned inside the combustion cylinder 4 . A plurality of igniters 32 are positioned in an area 38 of the lower lid 18 surrounded by the annular inlet 22 . These ignition parts 32 are located in the retention area. As shown in FIG. 2, in this embodiment the area 38 surrounded by the inlet 22 is circular. Although hidden behind the ion detectors 12 in FIG. 2, a plurality of igniters 32 are arranged concentrically in this region 38 below the ion detectors 12 . These igniters 32 are arranged so as to form one circle on concentric circles of a region 38 surrounded by the inlet 22 . The igniters 32 may be arranged on the concentric circles of this region 38 to form multiple circles. The positions where the ignition parts 32 are arranged are not limited to the concentric circles of the area 38 surrounded by the inlet 22 . A plurality of igniters 32 may be spirally arranged in this region 38 . The number of ignition units 32 may be one.

The lower lid portion 18 where the ignition portion 32 is located is located upstream of the flow of the mixed gas fuel. In this combustion device 2, the ignition part 32 is located upstream of the flow of the mixed gas fuel in order to burn the fuel sufficiently. The vertical distance between the ignition position of the ignition portion 32 (tip of the ignition portion 32) and the inlet 22 is preferably 50% or less, more preferably 25% or less of the vertical length of the body portion 16.

As shown in FIG. 1, in this embodiment the ignition section 32 comprises a discharge electrode 34 and a first ground electrode 36 . The discharge electrode 34 and the first ground electrode 36 are hook-shaped by bending a bar. The discharge electrode 34 and the first ground electrode 36 protrude inward from the lower lid portion 18 . Although not shown, the lower lid portion 18 is provided with a grounded terminal. The first ground electrode 36 is grounded by contacting this terminal. The discharge electrode 34 is electrically connected to the voltage generator. A high voltage is applied to the discharge electrode 34 from the voltage generator. As a result, sparks are generated between the tip of the discharge electrode 34 and the tip of the first ground electrode 36 . This ignites the fuel mixture. This ignition part 32 is a spark plug. The ignition part 32 may not be a spark plug. The igniter 32 may consist of a plasma jet spark plug.

The voltage generator generates a high voltage according to a signal from controller 14 . Although not shown, the voltage generator incorporates a primary coil and a secondary coil. A high voltage is intermittently generated on the secondary coil side by repeating disconnection and conduction of current in the primary coil.

The ion detector 12 detects ions inside the combustion cylinder 4 . As shown in FIG. 3, the ion detector 12 includes a detection section 40 and detection circuitry. 1 and 2 show the detector 40 among them. In this embodiment, the detection unit 40 includes a hook-shaped detection unit 40a and a ring-shaped detection unit 40b.

As shown in FIGS. 1 and 2, the hook-shaped detection portion 40a is located in the lower lid portion 18. As shown in FIG. As shown in FIG. 2 , a plurality of detectors 40 a are arranged on concentric circles in the area 38 surrounded by the inlet 22 . Each hook-shaped detection portion 40 a includes an application electrode 42 and a second ground electrode 44 . The application electrode 42 and the second ground electrode 44 of the hook-shaped detection unit 40a are hook-shaped by bending a bar. The application electrode 42 and the second ground electrode 44 protrude inward from the lower lid portion 18 . In the embodiment of FIG. 1, second ground electrode 44 is common with first ground electrode 36 . The second ground electrode 44 need not be common with the first ground electrode 36 . The application electrode 42 is electrically connected to the detection circuit section.

Although not shown, the application electrode 42 may be common to the discharge electrode 34 of the ignition section 32 . The application electrode 42 may be common with the discharge electrode 34 and the second ground electrode 44 may be common with the first ground electrode 36 . That is, the detection section 40a and the ignition section 32 may be common. Furthermore, a circuit in which the detection circuit section and the voltage generation section are integrated may be used. In this case, each igniter performs discharge ignition and ion detection.

A ring-shaped detection portion 40 b is located on the body portion 16 . FIG. 1 shows two ring-shaped detectors 40b. Each ring-shaped detection portion 40 b includes an application electrode 42 and a second ground electrode 44 . The application electrode 42 and the second ground electrode 44 are annular. The application electrode 42 and the second ground electrode 44 are attached to the inner surface of the cylindrical body portion 16 . This application electrode 42 is electrically connected to the detection circuit section. Although not shown, the body 16 is provided with a grounded terminal. The second ground electrode 44 is grounded by contacting this terminal.

A circuit example of the ion detector 12 is shown in FIG. As shown in FIG. 4, the detection circuit section consists of a power source E, a resistor R, and a voltage measurement section. The power source E applies a voltage to the application electrode 42 of the detection section 40 through the resistor R. In this example, a negative voltage is applied. For example, the voltage of this power supply E is -200V. When ions are present around the detection unit 40, the ions are attracted to the application electrode 42, and current (ion current) flows. The more ions present, the greater the ion current. The voltage measurement unit detects and amplifies the potential difference generated across the resistor R due to the ion current. A voltage measurement unit detects a voltage proportional to the ion current. From this voltage, the ion current is obtained. The ion detector 12 obtains an ion current as a result of ion detection.

A power supply E may apply a positive voltage to the application electrode 42 . For example, the voltage of the power supply E may be 200V. When electrons generated together with ions exist around the detection unit 40, the electrons are attracted to the application electrode 42, and an ion current flows. The more ions present, ie the more electrons, the greater the ion current. By measuring the voltage across the resistor R, the ion current is measured.

Ions are heavier than electrons. Ions move more slowly than electrons. When a negative voltage is applied to the application electrode 42, ions in the vicinity of the application electrode 42 are attracted. This method is suitable for detecting the amount of ions in the vicinity of the applied electrode 42 . Since electrons move easily, electrons are attracted from a wider range when a positive voltage is applied to the application electrode 42 than when a negative voltage is applied. This method is suitable for detecting the amount of ions over a wider range around the applied electrode 42 . Whether a positive or negative voltage is applied to the application electrode 42 is appropriately selected depending on the application, design concept, etc. of the combustion apparatus.

The configuration of the detection circuit section is not limited to that shown in FIG. A voltage measuring unit and a resistor may be provided in parallel with the power supply between the power supply and the application electrode 42 . Instead of the power source E in FIG. 4, it may have a capacitor and a charging circuit for charging the capacitor. In this configuration, current flows between this capacitance and the application electrode 42 . Further, the detection circuit section and the voltage generation section of the igniter 10 may be configured as a unit. For example, when the voltage generator applies a high voltage to the discharge electrode 34, the voltage generator may simultaneously charge the capacitance of the detection circuit.

Controller 14 is connected to igniter 10 , ion detector 12 and fuel mixer 8 . Symbol P in FIG. 1 represents a connection line with the igniter 10 , and symbol I represents a connection line with the ion detector 12 . As shown in FIG. 3, the controller 14 includes an ion analysis section, a valve control section, and an ignition control section. Detection results from all the ion detectors 12 are analyzed by the ion analysis unit. Based on this result, the valve control section controls the valve 30 of the fuel mixer 8 . This changes the fuel mixture ratio. The ignition control unit controls the ignition timing of each igniter 10 based on the analysis result of the ion analysis unit. The ignition timing of the igniter 10 is adjusted.

Controller 14 is typically implemented with a microcomputer. In this case, the circuits of the ion analysis section, the valve control section and the ignition control section of FIG. 3 do not exist separately. These functions are realized by a microcomputer and software. The controller 14 may have dedicated circuits for the ion analyzer, valve control and ignition control.

In combustion using the apparatus shown in FIGS. 1-4, at the start of combustion, first valve 30a and second valve 30b are opened by controller 14 to allow the fuel and air mixture to flow at a predetermined flow rate. is sent to the fuel injector 6 at . In this embodiment, a gaseous fuel mixture of ammonia and air is sent to the fuel injector 6 . The mixed gas fuel passes through the swirler 26 of the fuel injector 6 and is sent into the combustion cylinder 4 as a swirling airflow. The controller 14 drives the igniter 10 to ignite the fuel mixture. At this time, a plurality of igniters 10 are driven simultaneously. This causes the mixed gas fuel to burn. The ion detector 12 detects ions in the combustion cylinder 4 generated by this combustion as an ion current.

The combustion method according to the present invention comprises
(1) a reference range setting step of setting a reference range of ion current; and (2) a combustion step of continuously burning fuel.

In step (1) above, the correlation between the ion current and the parameter indicating the combustion state is measured. The straight line a in FIG. 5 shows the relationship between the mixture ratio (air-fuel ratio λ) of fuel (ammonia) and air and the ion current Iz (referred to as the λ-Iz function) under a predetermined mixed gas fuel flow velocity. ) are shown. FIG. 5 shows that the ion current Iz increases as the air-fuel ratio λ increases. A curve d in FIG. 5 represents the relationship between the air-fuel ratio λ at this time and the amount of oxides (nitrogen oxides NOx) emitted when the fuel is burned. The amount of nitrogen oxides has a peak at a specific air-fuel ratio λ. From the value of the air-fuel ratio λ at this time, the amount of nitrogen oxides decreases as the air-fuel ratio λ increases or decreases. In step (1) above, data representing the λ-Iz function is acquired as map data. A plurality of pieces of this map data are acquired according to the temperature and pressure in the combustion cylinder. Furthermore, the reference range of the ion current is set in consideration of the continuity of stable combustion, fuel efficiency, and oxide emissions. FIG. 5 shows an example of this reference range. These map data and reference range are stored in a memory circuit (not shown) of the controller.

In step (2) above, the igniter 10 is driven at regular time intervals while the mixed gas fuel is continuously sent to the combustion cylinder 4 . This causes the mixed gas fuel to burn continuously. The ion detector 12 detects ions in the combustion cylinder 4 at this time as an ion current. The controller 14 identifies the air-fuel ratio λ from the detected ion current and the λ-Iz function. The controller 14 adjusts the first valve 30a and the second valve 30 so that the ion current falls within the reference range set in (1) above. The air-fuel ratio λ is adjusted so that the ion current falls within the reference range set in (1) above.

In the above embodiment, the λ-Iz function (ie straight line a) under a given gaseous fuel flow velocity was used to determine the air-fuel ratio λ. In practice, the gaseous fuel flow rate may vary. As another embodiment of this combustion method, correction processing based on flow velocity fluctuations may be performed so that the air-fuel ratio λ can be specified more accurately. This method is described below.

FIG. 6 shows the relationship between flow velocity v and ion current Iz (referred to as the v-Iz function) at a reference air-fuel ratio λ. As shown in FIG. 6, the ion current Iz tends to increase as the flow velocity v increases. In this embodiment, the vIz function is also acquired as map data in step (1) above. Although FIG. 5 only shows the v-Iz function at the reference air-fuel ratio λ, this map data is obtained for a plurality of air-fuel ratios λ. These map data are stored in the memory circuit of the controller.

A dashed line b in FIG. 5 indicates the λ-Iz function in a high-speed state where the flow velocity is increased. A dashed line c indicates the λ-Iz function in the low speed state where the flow velocity is slowed down. In step (1) above, these data are also acquired as map data. These map data are stored in the memory circuit of the controller. In FIG. 5, λ-Iz functions are shown for three different flow velocities, but λ-Iz functions may be obtained for more flow velocities.

In this embodiment, in specifying the air-fuel ratio λ in step (2) above, the control unit 14 uses the map data of the vIz function from the detection result of the ion detector 12 to specify the flow velocity v. . At this time, the map data at the air heat ratio λ specified in the process prior to this process is used. Thereby, the control unit 14 specifies, for example, that the combustion state is the high speed state. At this time, the control unit 14 specifies the air-fuel ratio λ from the λ-Iz function in the high speed state in FIG. When using the map data of FIG. 6 next time, the map data at this air-fuel ratio λ will be used. This is used to identify the flow velocity v. This process is repeated.

The effects of the present invention will be described below.

In the fuel combustion apparatus 2 according to the present invention, the mixed gas fuel containing the fuel is fed into the combustion cylinder 4 as a swirling airflow. This mixed gas fuel forms a swirling flow, and there are portions where it flows at a slower speed than the main stream of the whirling air flow as a whole. This combustion device 2 can burn a flame-retardant fuel with a slow laminar combustion velocity.

The ignition part 32 of the igniter 10 of the combustion device 2 is located in a region where the mixed gas fuel stays inside the combustion cylinder 4 . Into this stagnation region, the swirling mixed gas fuel having a velocity lower than that of the main flow of the whirling airflow continuously flows. Therefore, the mixed gas fuel is repeatedly led to the ignition section 32 . The mixed gas fuel repeatedly passes through the vicinity of the ignition section 32 . Thereby, the ignition part 32 can give a large amount of energy to the mixed gas fuel. This device can provide sufficient energy for ignition even to fuel with high ignition energy.

This combustion apparatus 2 includes a detector 40 of the ionizer 12 inside the combustion cylinder 4 . The combustion state of the mixed gas fuel can be grasped by detecting the ions generated by the combustion by the detection unit 40 . Since this combustion device 2 is provided with a controller 14 that adjusts the mixture ratio of fuel based on the detection result, it is possible to perform appropriate air-fuel ratio control based on the grasped combustion state. This contributes to the continuation of stable combustion. In this combustion device, combustion of flame-retardant fuel can be stably continued.

As shown in FIG. 1, there is preferably a detection section 40 located near the ignition section 32 . This ignition part 32 is located in the retention area. In the detection section 40 near the ignition section 32, the detected ion current reflects the combustion state of the region to which energy is effectively supplied, so that the state of the flame kernel can be grasped. With this device, air-fuel ratio control and ignition timing control of the igniter 60 based on the state of the flame kernel can be realized. In this combustion device 2, flame-retardant fuel can be burned stably and efficiently.

The fuel mixture ratio affects the amount of oxides produced. Adjusting the fuel mixture ratio can help reduce the formation of oxides. In this combustion device 2, emission of oxides can be suppressed while continuing stable combustion of flame-retardant fuel.

A combustion method using this apparatus includes a step of measuring the correlation between a parameter representing the combustion state of fuel and the ion current to set the reference range of the ion current. By setting the ion current value detected by the ion detector 12 within this reference range in the step of continuously burning the fuel, it is possible to continue to maintain an appropriate combustion state.

The parameter representing the combustion state preferably includes the amount of oxides emitted. As a result, combustion in which the emission of oxides is more effectively suppressed can be realized. This combustion method can stably burn a flame-retardant fuel while suppressing the emission of oxides.

When the ignition section 32 includes the discharge electrode 34 and the first ground electrode 36, and the detection section 40 includes the application electrode 42 and the second ground electrode 44, the first ground electrode 36 and the second ground electrode 44 are common. preferably. By doing so, it is possible to prevent these ground electrodes from interfering with efficient combustion.

As shown in FIG. 1, it is preferable that a detector 40 is arranged on the inner surface of the body 16 from the side of the lower lid 18 toward the opposite side. By doing so, the combustion state at a position above the fuel inlet 22 can be detected. This contributes to setting an appropriate fuel mixture ratio and ignition timing of the igniter 10 . In this combustion device 2, it is possible to stably and efficiently burn the flame-retardant fuel while suppressing the emission of oxides.

As mentioned above, the igniter 32 is preferably located in the region 38 of the lower lid 18 surrounded by the annular inlet 22 . Inside the annular inlet 22, the mixed gas fuel flow is stagnant. By arranging the ignition portion 32 of the igniter 10 in this region 38 , the mixed gas fuel in the swirl flow is repeatedly led to the ignition portion 32 . The mixed gas fuel repeatedly passes through the vicinity of the ignition section 32 . Therefore, the device 2 can provide sufficient energy for ignition even to flame-retardant fuel. Moreover, these igniters 32 are positioned upstream in the flow of the mixed gas fuel. These realize stable ignition and combustion even for flame-retardant fuel.

As mentioned above, when the area 38 surrounded by the inlet 22 is circular, the igniters 32 are preferably arranged concentrically with this area 38 . By doing so, the mixed gas fuel can be uniformly ignited around the inlet 22 . As a result, the mixture gas fuel can be stably ignited.

Although not shown, the combustion device 2 may have a temperature sensor that measures the temperature inside the combustion cylinder 4 . This temperature sensor is connected to the controller 14 and the temperature measurement results are sent to the controller 14 . In general, fuel becomes more flammable when the temperature inside the combustion tube 4 increases. Ammonia also improves in combustibility as the temperature rises, and the amount of nitrogen oxides NOx emitted decreases. In this combustion device 2, the controller 14 adjusts the fuel mixture ratio based on the temperature measurement result. A controller 14 controls the ignition timing of the igniter 10 based on the temperature measurements. These contribute to the continuation of stable combustion. In this combustion device 2, stable combustion can be continued.

Although not shown, the combustion device 2 may have a pressure sensor that measures the pressure inside the combustion cylinder 4 . This pressure sensor is connected to the controller 14 and the pressure measurement results are sent to the controller 14 . In general, fuel becomes more flammable when the pressure inside the combustion tube 4 increases. Ammonia is also more combustible when the pressure is increased, and the amount of exhausted nitrogen oxides NOx is also reduced. In this combustion device 2, the controller 14 adjusts the fuel mixture ratio based on the pressure measurement result. Controller 14 controls the ignition timing of igniter 10 based on the pressure measurement. These contribute to the continuation of stable combustion. In this combustion device 2, stable combustion can be continued.

Although not shown, the combustion device 2 may have a drive mechanism for controlling the angle of the vanes of the swirler 26. This drive mechanism is connected to the controller 14 . The controller 14 adjusts the swirl ratio of the swirling airflow by controlling the angles of the blades through the drive mechanism. Controller 14 adjusts the vane angle based on the above ion current, temperature and pressure measurements. These contribute to the continuation of stable combustion. In this combustion device 2, stable combustion can be continued.

FIG. 7 is a conceptual diagram showing a fuel combustion device 52 according to another embodiment of the present invention. In this figure, part of the device is shown in cross section. This combustion device 52 comprises a combustion cylinder 54 , a fuel injector 56 , a fuel mixer 58 , an igniter 60 , an ion detector 62 and a controller 64 . In this embodiment, the material of the combustion liner 54 is steel. The fuel injector 56, fuel mixer 58 and controller 64 of this combustion device 52 are the same as those devices of the combustion device 2 of FIG. The direction indicated by the arrow X in FIG. 7 is the downward direction of the combustion device 52, and the opposite direction is the upward direction.

The igniter 60 includes an ignition section 66 and a voltage generation section. FIG. 7 shows the ignition section 66 among them. As shown in FIG. 7, in this embodiment, the ignition portion 66 is located in the lower lid portion 68 and the body portion 70 . A plurality of igniters 66 are positioned on the lower lid portion 68 and the body portion 70 . The ignition portion 66 located in the lower lid portion 68 is located in the retention area, like the ignition portion 32 in FIG. Among the ignition portions 66 located in the body portion 70, there is an ignition portion 66 located in a region where the mixed gas fuel does not stay. For example, there is an ignition portion 66 located where the main stream of swirling airflow flows. In this embodiment, the ignition portion 66 located in the retention region and the ignition portion 66 located in a region away from the retention region are mixed. Although not shown, the voltage generator of this embodiment is the same as the voltage generator of FIG.

The ignition portion 66 located on the lower lid portion 68 includes a discharge electrode 72 and a first ground electrode 74 . The first ground electrode 74 is grounded by contacting the grounded lower lid portion 68 . The configuration of the discharge electrode 72 is the same as that of the discharge electrode 34 in FIG.

The ignition parts 66 located in the body part 70 are arranged from the lower lid part 68 side toward the opposite side. Each ignition section 66 includes a discharge electrode 72 and a first ground electrode 74 . The discharge electrode 72 and the first ground electrode 74 are hook-shaped by bending a bar. The discharge electrode 72 and the first ground electrode 74 of the ignition portion 66 located in the trunk portion 70 protrude inward from the inner surface of the trunk portion 70 . The first ground electrode 74 is grounded by contacting the grounded trunk 70 . The discharge electrode 72 is electrically connected to the voltage generator. A high voltage is applied to the discharge electrode 72 from the voltage generator. As a result, sparks are generated between the tip of the discharge electrode 72 and the tip of the first ground electrode 74 . This ignites the fuel mixture.

The ion detector 62 includes a detection section 76 and a detection circuit section. FIG. 7 shows the detection section 76 among them. As shown in FIG. 7 , the detectors 76 are located in the lower lid portion 68 and the body portion 70 . A plurality of detectors 76 are positioned on the lower lid portion 68 and the body portion 70 . In this embodiment, all detectors 76 are hook-shaped. The configuration of the detection section 76 located in the lower lid section 68 is the same as that of the detection section 40 in FIG. Although not shown, the detection circuitry of this embodiment is the same as the detection circuitry of FIG.

The detectors 76 positioned on the body 70 are arranged from the lower lid 68 side toward the opposite side. Each detection section 76 has an application electrode 78 and a second ground electrode 80 . The application electrode 78 and the second ground electrode 80 are hook-shaped by bending a bar. The application electrode 78 and the second ground electrode 80 positioned on the trunk portion 70 protrude inward from the inner surface of the trunk portion 70 . This detection section 76 is located near the ignition section 66 located in the body section 70 . In the embodiment of FIG. 7, this second ground electrode 80 is common with the first ground electrode 74 of the ignition portion 66 located on the barrel 70 . The second ground electrode 80 need not be common with the first ground electrode 74 . The application electrode 78 is electrically connected to the detection circuitry.

In this combustion device 52 , the ignition portion 66 of the igniter 60 is located in the body portion 70 in addition to the lower lid portion 68 . These ignition portions 66 are arranged from the lower lid portion 68 side toward the opposite side. In this combustion device 52 , the fuel can be ignited also at the center and upper part of the body 70 . In this combustion device 52 , the fuel can be burned in a well-balanced manner in the entire combustion cylinder 54 . As a result, stable ignition and combustion are realized even for flame-retardant fuel.

In this combustion device 52 , the detection portion 76 of the ion detector 62 is located near the ignition portion 66 of the lower lid portion 68 and near the ignition portion 66 of the body portion 70 . That is, the detector 76 is positioned near the ignition part 66 located in the retention area and near the ignition part 66 located in an area away from the retention area. In the detection unit 76 near the ignition unit 66 located in the retention area, the detected ion current reflects the combustion state of the area to which energy is effectively supplied, so that the state of the flame kernel can be grasped. Become. With this device, air-fuel ratio control and ignition timing control of the igniter 60 based on the state of the flame kernel can be realized. This contributes to the formation of a stable flame kernel. This combustion device 52 can continue stable combustion.

In the detection unit 76 near the ignition unit 66 located in a region away from the retention region, the detected ion current reflects the combustion state in the region where the fuel flows at a relatively high speed, so the stability of combustion can be grasped. It becomes possible to With this device, air-fuel ratio control and ignition timing control of the igniter 60 can be realized based on the stability of combustion. This contributes to stabilization of combustion.

Although not shown, the combustion device 52 may have a plurality of temperature sensors arranged in the combustion cylinder 54 from the lower cover side toward the opposite side. These temperature sensors measure the temperature distribution within the combustion liner 54 . In this combustion device 52, the controller 64 controls the ignition timing of each igniter 60 based on these temperature measurement results. Appropriate ignition timing of the igniter 60 can be achieved depending on where the igniter 66 is located. These contribute to the continuation of stable combustion. This combustion device 52 can continue stable combustion.

Although not shown, the combustion device 52 may have a plurality of pressure sensors arranged in the combustion cylinder 54 from the lower cover side toward the opposite side. These pressure sensors measure the distribution of pressure within the combustion canister 54 . In this combustion device 52, the controller 64 controls the ignition timing of each igniter 60 based on these pressure measurement results. Appropriate ignition timing of the igniter 60 can be achieved depending on where the igniter 66 is located. These contribute to the continuation of stable combustion. This combustion device 52 can continue stable combustion.

FIG. 8 is a view of the bottom cover 94 of a fuel combustion device 92 according to still another embodiment of the present invention, viewed from above. This combustion device 92 is the same as combustion device 2 of FIGS.

As shown in FIG. 8, the lower lid portion 94 of the combustion device 92 is provided with an inlet 100 . A mixed gas fuel containing fuel is sent from this input port 100 . In this embodiment, the inlet 100 has a circular shape.

A fuel injector 96 is positioned below the lower lid portion 94 of the combustion canister. Fuel injector 96 includes swirler 102 . In FIG. 8, the swirler 102 located underneath is visible through the inlet 100 . The mixed gas fuel becomes a swirling airflow by passing through the swirler 102 . The mixed gas fuel is sent into the combustion tube as a swirling airflow. The swirler 102 material is typically steel.

Although not visible in FIG. A plurality of igniters are arranged in the lower lid portion 94 so as to surround the circular inlet 100 . The area around the inlet 100 is a retention area. Into the stagnation region, the swirl-like mixed gas fuel flows continuously at a velocity lower than that of the main stream of the whirling airflow. Therefore, the mixed gas fuel is repeatedly guided to the ignition section. The gaseous fuel mixture repeatedly passes through the vicinity of the ignition section. Thereby, the ignition part 32 can give a large amount of energy to the mixed gas fuel. This device can provide sufficient energy for ignition even to fuel with high ignition energy.

In this embodiment, a plurality of igniters are arranged concentrically with a circular inlet 100 . These ignition parts are arranged so as to form one circle on the concentric circle of the inlet 100 . By doing so, the mixed gas fuel can be uniformly ignited around the inlet 100 . As a result, the mixture gas fuel can be stably ignited.

Although not shown, these igniters may be arranged to form multiple circles on the concentric circle of the inlet 100 . These igniters may be spirally arranged so as to surround the inlet 100 . By doing so, the mixed gas fuel can be uniformly ignited around the inlet 100 . As a result, the mixture gas fuel can be stably ignited.

A detection section 104 of the ion detector 98 is arranged in the lower lid section 94 . This detection unit 104 is hook-shaped. As shown in FIG. 8, the detectors 104 are arranged concentrically with the circular inlet 100 . The detection unit 104 is positioned near the ignition unit. In the detection unit 104, the state of combustion in the region to which energy is effectively supplied is reflected in the detected ion current, so the state of the flame kernel can be grasped. With this device, air-fuel ratio control and ignition timing control of the igniter based on the state of the flame kernel can be realized.

In the combustion devices shown in the above embodiments, fuel was delivered continuously to the combustion device. This combustion device can also be applied to internal combustion engines such as automobiles. In this case, feeding fuel into the combustion cylinder and igniting the fuel are repeated as one cycle.

As described above, according to the present invention, it is possible to realize a combustion apparatus capable of stably continuing combustion of flame-retardant fuel. From this, the superiority of the present invention is clear.

The fuel combustion apparatus described above is used in various types of equipment.

2, 52, 92 Combustion device 4, 54 Combustion cylinder 6, 56 Fuel injector 8, 58 Fuel mixer 10, 60 Ignitor 12, 62, 98. Ion detector 14, 64 Controller 16, 70 Body 18, 68, 94 Lower lid 20 Bottom 22, 100 Insert 24 Housing Body 26, 102... Swirler 28... Fuel tank 30... Valve 30a... First valve 30b... Second valve 32, 66... Ignition part 34, 72... Discharge electrode 36 , 74... First ground electrode 38... Area surrounded by inlet 40, 76... Detector 40a... Hook-shaped detector 40b... Ring-shaped detector 42, 78, 104... Application electrode 44, 80... Second ground electrode

Claims (15)

a combustion cylinder, a fuel injector that feeds a mixed gas fuel into the combustion cylinder as a swirl flow, an igniter that has an ignition part in the combustion cylinder, an ion detector that has a detection part in the combustion cylinder, a controller that adjusts the mixture ratio of the mixed gas fuel according to the detection result of the ion detector;
The combustion cylinder has a cylindrical body and a lower lid covering the end of the body,
The lower lid portion is provided with an inlet into which the mixed gas fuel is sent,
A fuel combustion device, wherein the ignition section and the detection section are arranged in the lower lid section. 2. A fuel combustion apparatus according to claim 1, wherein said ignition portion is located in a region where said mixed gas fuel stays in said combustion cylinder. 3. The fuel combustion device according to claim 1, wherein the detector is common with the ignition unit. 2. The ignition section comprises a discharge electrode and a first ground electrode, the detection section comprises an application electrode and a second ground electrode, and the first ground electrode and the second ground electrode are common. 3. Or the fuel combustion device according to 2. 3. The fuel combustion device according to claim 1, wherein the detection section is adjacent to the ignition section. The fuel combustion device according to any one of claims 1 to 5, wherein the detectors are arranged in the lower cover and the body. The inlet has an annular shape,
7. The fuel combustion device according to any one of claims 1 to 6, wherein the ignition section and the detection section are arranged in a region of the lower lid section surrounded by the inlet. The inlet has a circular shape,
7. The fuel combustion device according to any one of claims 1 to 6, wherein the ignition section and the detection section are arranged around the inlet in the lower lid section. 9. The fuel combustion device according to any one of claims 1 to 8, wherein a plurality of said ignition units are present. 10. The fuel combustion apparatus according to claim 9, wherein at least one ignition part is located in a region in which the mixed gas fuel does not stay in the combustion cylinder. 11. The fuel combustion device according to claim 9 or 10, wherein the ignition part is arranged in the lower lid part and the body part. 12. The fuel combustion device according to any one of claims 1 to 11, wherein the gaseous fuel mixture contains ammonia. 2. The combustion cylinder further comprises an upper lid portion covering an end of the body portion opposite to the lower lid portion, and the upper lid portion is provided with an output port for ejecting flame. 13. The fuel combustion device according to any one of 12 to 12. Equipped with a combustion step that continuously burns fuel,
In the combustion step, the gaseous fuel is ignited while the gaseous fuel is sent into the combustion cylinder as a whirling current, ions generated by this combustion are detected, and the mixture ratio of the gaseous fuel is adjusted based on the detection result. death,
Further comprising, prior to the combustion step, setting a reference range of ion detection results based on a correlation between a parameter representing the combustion state of the mixed gas fuel and ion detection results,
The fuel combustion method, wherein the mixing ratio of the mixed gas fuel is adjusted so that the ion detection result falls within the reference range. 15. The method of burning fuel according to claim 14, wherein the parameter representing the state of combustion of the mixed gas fuel includes the amount of oxides emitted during combustion.

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