JPH0368294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air-fuel ratio control device for a gun-type burner, and more particularly to an air-fuel ratio control device for a gun-type burner that controls the air-fuel ratio to the stoichiometric air-fuel ratio.

[Conventional technology]

In conventional gas type burners, fuel is supplied from a fuel pump etc. to a fixed nozzle via a feed pipe, and the fuel is injected from the nozzle, and the air blown by the rotation of a fan is mixed with the injected fuel to ignite. The rod is ignited and burned to generate hot air. The temperature of the hot air from the gun-type burner that is burned as described above is determined by detecting the temperature of the hot air generated by the gun-type burner using a temperature sensor, etc., and comparing the detected hot air with a preset temperature. This is controlled by controlling the amount of fuel supplied to the gun-type burner. Further, at this time, the air-fuel ratio of the gun-type burner is controlled to the stoichiometric air-fuel ratio by controlling the air amount supplied by a fan or the like based on the fuel amount.

[Problem that the invention seeks to solve]

However, when controlling the amount of fuel supplied to the gun-type burner, the particle size of the spray particles injected from the nozzle of the gun-type burner changes depending on the injection pressure. Since the fuel is large, the particles are fine and complete combustion is achieved, but in the case of small combustion with a small amount of fuel injection,
Since the injection pressure is low, the particles are coarse, and even if the air-fuel ratio is controlled to the stoichiometric air-fuel ratio, the atomization is poor and incomplete combustion tends to occur, resulting in soot generation.

The present invention has been made to solve the above problems, and is an air-fuel ratio of a gun type burner that can completely burn fuel regardless of the combustion amount and easily control the air-fuel ratio to the stoichiometric air-fuel ratio. The purpose is to obtain a control device.

[Means for solving problems]

In order to achieve the above object, the present invention includes a nozzle that includes a nozzle hole and injects fuel from the nozzle hole at a constant pressure and at a predetermined angle, and a hole that allows the fuel to pass through and is disposed on the fuel injection side of the nozzle. a moving device for moving the nozzle so that a nozzle hole of the nozzle and a hole of the shielding plate approach or separate from each other, an inspection means for detecting the position of the nozzle, and a position of the nozzle. control means for controlling the amount of air so that the air-fuel ratio becomes the stoichiometric air-fuel ratio based on;
It consists of:

[Effect]

In the present invention, a fixed amount of fuel is injected from the injection hole of the nozzle at a fixed pressure. When the nozzle is moved in a direction in which the injection hole of the nozzle and the hole of the shielding plate approach each other, the amount of fuel shielded by the shielding plate decreases, and the amount of combustion increases. Conversely, if the nozzle is moved in a direction in which the injection hole of the nozzle and the hole of the shielding plate are moved away from each other, the amount of fuel shielded by the shielding plate increases, and the amount of fuel burned decreases. In this way, the amount of combustion can be adjusted by moving the position of the nozzle.

Further, since combustion is injected from the injection hole of the nozzle at a constant pressure, the atomization state of the fuel is always constant regardless of the age of combustion, and the fuel can be completely combusted. Furthermore, in the present invention, the amount of fuel to be combusted and the amount of air can be adjusted separately, and the amount of fuel to be combusted can be detected based on the position of the nozzle, so the amount of air can be adjusted so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. can be easily controlled.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

A first embodiment of the present invention is shown in FIGS. 1 to 7, and FIG. 1 shows the configuration of a gun type burner. In the gun-type burner, fuel is sent from a fuel pump (not shown) to a nozzle adapter 14 through a fuel pipe 12 at a constant pressure (and a constant amount) to achieve a good atomization state. This nozzle adapter 14 can be moved linearly along the axis of a nozzle adapter guide 18 fixed by a fixing plate 16, and the nozzle adapter 14 is moved linearly by a moving device 20 via a rod 22. The nozzle hole 26 for injecting fuel onto the nozzle tip 24 provided at the tip of the nozzle adapter 14
is now moved in a straight line.

In addition, a spring 28 provided on the rod side of the nozzle adapter guide 18 allows the nozzle adapter 14 to be
The moving device 20 is pressed in the direction of the rod 22.
The position of the nozzle can be determined by

On the fuel injection side of the nozzle tip 24, a shielding plate 32 with a hole 34 bored in the center is fixed to an outer cylinder 30 provided at the other end of the nozzle adapter guide 18, and the shielding plate 32 is provided with a hole 34 in the center thereof. When fuel is injected from the nozzle holes 26, only the fuel that has passed through the holes 34 of the shielding plate 32 is supplied for combustion. The fuel shielded by the shielding plate 32 according to the position of the nozzle hole 26 is returned to the fuel tank by a fuel return pipe 38 provided through the shielding plate 32 and the outer cylinder 30. There is. Thus, by keeping the amount and pressure of fuel injected from the nozzle holes 26 constant, the amount of fuel to be combusted is controlled.

Further, in the lower part of the shielding plate 32, there is a return hole 36 for passing the fuel dripping from the hole 34 of the shielding plate 32 along the outer peripheral surface thereof to the fuel return pipe 38.
is drilled. Note that the nozzle position sensor 40 that indirectly detects the position of the nozzle is connected to the moving device 20.
is attached to.

On the other hand, the amount of air supplied necessary for combustion is controlled by controlling the fan motor 44 of the Sirotskov fan 42.
The fuel passes through the holes 34 of 2 and is mixed with the flame holder (dehyder user) 48, and is ignited by the ignition rod 52 connected to the ignition transformer 50 and protruding between the frame holder 48 and the outer cylinder 30. It is now being burned. The fan motor 44 is provided with a rotation speed sensor 58 that detects the rotation speed of the fan.

Also, there is a hot air temperature sensor 54 that detects the temperature of the hot air generated by the gun type burner, and a setting device 56 that sets the temperature of the hot air generated by the burner.
is provided. The moving device 20, nozzle position sensor 40, fan motor 44, hot air temperature sensor 54, setting device 56, and rotation speed sensor 58 are each connected to an electronic control circuit 60 composed of a microcomputer or the like.

The moving device 20 and nozzle position sensor 40 will be explained in more detail with reference to FIGS. 2 and 3. This moving device 20 uses a thermal expansion body to move the nozzle position, and the nozzle position sensor 40 indirectly detects the nozzle position.

As shown in FIGS. 2 and 3, the moving device 20 is a bimetallic insulator (silicon rubber, Nomex, Kapton, etc.) 80 with a film heater 84 on which a nichrome wire 82 is printed. 86. According to this moving device 20, the shape of the bimetal 86 changes by increasing the temperature of the hearter 84, the position of the nozzle hole 26 on the nozzle tip 24 moved by pushing the rod 22 is moved, and the nozzle tip 24 is moved. The amount of combustion reaches its maximum when it comes into contact with the shielding plate 30. Furthermore, when the temperature of the heater is lowered and the shape of the bimetal 86 no longer changes, the amount of combustion becomes the minimum. The nozzle position sensor includes a temperature sensor 88 that detects the temperature of the heater 84.
The nozzle position is indirectly detected.

As shown in FIG. 4, the electronic control circuit 60 includes a central processing unit (CPU) 62, a read-only memory (ROM) 64, a random access memory (RAM) 66, an input port 68, an output port 70, and It is configured to include a data bus and a control bus 72 that connect these. The setting device 56 and the rotation sensor 58 are connected to the input port 68, and the hot air temperature sensor 54 and the nozzle position sensor 4 are connected to the input port 68 via an analog-to-digital converter (ADC) 74 and a multiplexer 76.
0 is connected.

The CPU 62 has a multiplexer 76 and an ADC 7
4, and sequentially converts the outputs of the hot air temperature sensor 54 and the nozzle position sensor 40 into digital signals.
Store it in RAM66. The output port 70 is connected to the moving device 2 via drive circuits 77 and 78, respectively.
0, is connected to the fan motor 44, and the CPU 62 is
moving device 20 by controlling the drive circuit;
Controls the fan motor 44. The ROM 64 stores in advance a control routine program to be described below.

FIG. 5 shows the control routine of the first embodiment, in which when the gun type burner is ignited, the step
At step 150, the hot air temperature T detected by the hot air temperature sensor is read from the RAM, and the step
In 152, it is determined whether the hot air temperature T read in step 150 is higher than the preset temperature To, and if the hot air temperature T is higher than the set temperature To, the current supplied to the heater is controlled in step 154. By doing so, the heater temperature HT is lowered. As a result of the heater temperature being lowered, the position of the nozzle is retracted as shown in FIG. Further, as shown in FIG. 7, as a result of the nozzle being moved back, more fuel is shielded by the shielding plate, and the amount of fuel supplied is reduced.

Further, if the hot air temperature T is lower than the set temperature To, the heater temperature HT is increased in step 156. As a result of the heater temperature being increased, the position of the nozzle is advanced as shown in FIGS. 6 and 7, and the amount of fuel injected from the nozzle is increased. Then, in step 158, the temperature sensor 8
The heater temperature HT detected in step 8 is read. Since the heater temperature is proportional to the amount of nozzle movement, the nozzle position is indirectly read.

In step 160, the fuel supply amount F is calculated from the heater temperature HT. In step 162, the air supply amount Q is calculated from the fuel supply amount F calculated in step 160 so as to reach the stoichiometric air-fuel ratio. The calculated air supply amount Q is converted to the fan rotation speed NEo. The current fan rotation speed NE is read in step 166, and the current fan rotation speed NE is read in step 168.
It is determined whether NE is less than or equal to the fan rotation speed NEo calculated in step 164. If the result is affirmative, the fan rotation speed is increased in step 170; if negative, the fan rotation speed is increased in step 172. The fan rotation speed is reduced and the air-fuel ratio is controlled to the stoichiometric air-fuel ratio.

Note that the moving device 20 for moving the nozzle is a cylinder 90 as shown in FIG.
A moving device can be used in which oil 92 is injected into the nozzle tip and when heated by a heater 94 similar to the above, the oil 92 is expanded and the rod 22 is moved via the piston 91 to linearly move the position of the nozzle tip 24. . In this case, a temperature sensor 96 that detects the temperature of the heater 94 can be used as a means for indirectly detecting the position of the nozzle. Moreover, a shape memory alloy can also be used as a moving device.

Further, as a means for controlling the air supply amount, as shown in FIG. 9, the number of rotations of the fan 42 is kept constant, and a damper 98 is provided at the air intake port of the fan 42 to control the damper motor 100. The damper 98 can be used to control the opening degree of the damper 98 and control the amount of air.

Next, according to FIGS. 10 to 12, the second embodiment of the present invention will be described.
An example will be explained. In FIGS. 10 to 12, parts that are the same as those in the first embodiment are given the same reference numerals, and explanations thereof will be omitted. FIG. 10 shows the configuration of a gun type burner, in which a sensor capable of directly detecting the amount of movement of the rod 22 is used as the nozzle position sensor 40.

As shown in FIG. 11, the moving device 20 is composed of a motor (step motor) 104 and a cam 102 fixed to the output shaft of the motor 104. When the cam 102 is rotated by the motor 104, The rod 22 is moved by the cam 102 so that the position of the nozzle tip 24 is moved. Further, the nozzle position detection means includes limit switches SW1, SW2, SW3, and SW4 arranged in order in a direction perpendicular to the axis of the rod 22, one end of which is rotatably supported on the upper end of the nozzle position sensor 40, and the other end of which is rotatably supported between the dog 108. movable piece 106 supported by
It is composed of. This nozzle position sensor 4
0, the movable piece 106 is swung by a dog 108 provided on the rod 22, so that the limit switches are turned on in the order of SW1, SW2, SW3, and SW4.

FIG. 12 shows the control routine of the second embodiment. When the gun type burner is ignited, the hot air temperature T is read in step 174, and the hot air temperature T read in step 174 is preset in step 176. It is determined whether the hot air temperature T is higher than the set temperature To, and if the hot air temperature T is higher than the set temperature To, the nozzle position is moved back by reversing the motor 104 in step 178, and the amount of heat supplied is reduced. Ru. Also, the hot air temperature T is the set temperature
When the temperature is lower than To, the nozzle is advanced by rotating the motor 104 forward in step 180.
The amount of fuel supplied is increased.

In step 182, the position of the nozzle is determined based on the on/off state of the limit switch, in step 184, the fuel supply amount F is calculated based on the nozzle position, and in step 186, the theoretical fuel supply amount F is calculated from the fuel supply amount F calculated in step 184. The air supply amount Q is calculated to match the fuel ratio, and in step 188 the air amount Q calculated in step 186 is calculated.
is calculated as the fan rotation speed NEo.

Current fan rotation speed NE at step 200
is read, and in step 202 it is determined whether the current fan rotation speed NE is less than or equal to the fan rotation speed NEo calculated in step 188. If it is affirmative, the fan rotation speed is increased in step 204. If the answer is NO, the fan rotation speed is reduced in step 206, and the air-fuel ratio is controlled to the stoichiometric air-fuel ratio.

Figure 13 shows a routine for controlling the air-fuel ratio to the stoichiometric air-fuel ratio without using a temperature sensor.
In step 208, the set temperature To is read,
In step 210, the number of pulses NP of the step motor of the nozzle moving device corresponding to the set temperature To is selected based on a table previously stored in the ROM as shown in FIG. Drive pulses are supplied to the step motor and the number of drive pulses is counted, and in step 212, when the count value matches the number of pulses NP selected in step 210, the drive of the motor is stopped.
In other words, the position of the nozzle is moved to reduce the hot air temperature.
A predetermined fuel supply amount corresponding to To is set.

In step 214, the air amount Q corresponding to the set temperature To is selected from the table shown in FIG. This air amount Q corresponds to the stoichiometric air-fuel ratio. At step 216, the air supply amount Q selected at step 214 is converted into fan rotation speed NE. Current fan rotation speed in step 218
NE is read, and in step 220 it is determined whether the current fan rotation speed NE is less than or equal to the fan rotation speed NEo converted in step 216. If it is affirmative, the fan rotation speed is increased in step 222, If denied, step
At 224, the fan rotation speed is reduced and the air-fuel ratio is controlled to the stoichiometric air-fuel ratio.

Note that the means for controlling the air amount may be configured to control the air amount by controlling the opening degree of the damper 98 as explained in FIG.

In addition to the above, the moving device 20 for moving the nozzle is also shown in FIGS. 2, 8, 11, and 15.
The moving devices shown in FIGS. 19 to 19 can be used.

In the moving device shown in FIG. 15, a continuous groove 112 is provided on the upper surface of a cylinder 110, and when the cylinder 110 is rotated by a motor (step motor) 114, a pin 116 on a rod 22 is aligned with the groove 112. The rod 22 is moved.

In the moving device shown in FIG. 16, a pinion 118 is rotated by a motor (step motor) 120, a rack 122 moves linearly, and a rod 22 is moved.

In the moving device shown in FIG. 17, the diaphragm 126 is
moves the piston 128 so that the rod 22 is moved linearly.

In the moving device shown in FIG. 18, a piston 132 is moved by hydraulic pressure sent from a hydraulic device 130, and the rod 22 is moved.

The moving device shown in FIG. 19 uses a step motor, and the rotor 1 is moved by changing the current supply to the stator coil 134 according to a signal from an electronic control circuit.
36 rotates forward or backward, and the rod 22 is moved.

〔Effect of the invention〕

As explained above, according to the present invention, the nozzle is configured to inject combustion at a constant pressure from the injection hole, and the amount of air is controlled based on the position of the nozzle so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. As a result, the fuel can be combusted at an unprecedented rate regardless of the combustion amount, and the air-fuel ratio can be easily controlled to the stoichiometric air-fuel ratio.

In addition, in general, the spray pattern (spray angle, direction) of the nozzle varies depending on each nozzle and is not stable, and it is necessary to inspect and select each nozzle before use. Since the pattern is cut and formed at an arbitrary angle, there is a synergistic effect in that there are no problems as in the conventional method.

Conventionally, the fuel amount was controlled by adjusting the fuel amount stepwise using several on-off solenoid valves, etc., but as in this embodiment, the fuel amount can be continuously operated steplessly. By adopting a mobile device, the amount of fuel supplied and the amount of fuel based on it can be adjusted and controlled steplessly (linearly) and sharply.
It has this excellent effect.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a gun type burner showing a first embodiment of the present invention, Fig. 2 is a schematic diagram showing a moving device of the first embodiment, and Fig. 3 is a schematic diagram showing a - line cross section in Fig. 2. Cross-sectional view, Figure 4 is similar to Figure 1 and Figure 1.
0 is a block diagram showing details of the control circuit, FIG. 5 is a flowchart showing the control routine of the first embodiment, and FIG.
Figure 7 is a diagram showing the relationship between heater temperature and nozzle movement amount, Figure 7 is a diagram showing the relationship between nozzle movement amount and fuel supply amount, Figure 8 is a schematic diagram showing another moving device, and Figure 9 is a diagram showing the relationship between nozzle movement amount and fuel supply amount. The figure is a schematic diagram showing a damper of a gun type burner, FIG. 10 is a schematic diagram of a gun type burner showing a second embodiment of the present invention, FIG. 11 is a schematic diagram showing a moving device of the second embodiment, 13 is a flowchart showing another control routine, FIG. 14 is an explanatory diagram showing details of the routine in FIG. 13, and FIGS.
17, 18, and 19 are schematic diagrams showing a moving device of a second embodiment. 20...Movement device, 24...Nozzle chip, 2
6... Nozzle hole, 32... Shielding plate, 34... Hole, 40
... Nozzle position sensor, 42 ... Sirotskov fan.

Claims (1)

[Claims] 1. A nozzle having a nozzle hole and injecting fuel at a constant pressure and at a predetermined angle from the nozzle hole; a shielding plate having a hole through which fuel passes and disposed on the fuel injection side of the nozzle; a moving device for moving the nozzle so that the hole and the hole in the shielding plate approach or move away from each other; a detection means for detecting the position of the nozzle; and an air-fuel ratio or a stoichiometric air-fuel ratio based on the position of the nozzle. An air-fuel ratio control device for a gun-type burner, comprising: a control means for controlling an air amount.