JPH0454848B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spray combustion device for domestic or industrial use, and particularly to a small spray combustion device for vehicle use.

The conventional in-vehicle spray combustion device was developed in Japanese Patent Application Laid-open No.
As disclosed in Japanese Patent No. 147921, a fuel injection valve that sprays liquid fuel from the closed end side to the open end side is provided concentrically in the swirling chamber at the center of the swirling airflow generating device. The structure is such that liquid fuel is sprayed into the center of the swirling airflow.

A first combustion tube having a larger diameter than the swirl chamber is concentrically connected to the open end of the swirl chamber, and a first combustion tube is connected to the outlet of the first combustion tube.
The second combustion cylinders are concentrically connected through the throttle, and the second
The combustion tube is formed to have a larger diameter than the first combustion tube, and a second throttle is provided at the outlet of the second combustion tube.

In this spray type combustion device, when the swirling air flow, that is, the mixture flow, in which liquid fuel is sprayed in the center, flows from the swirling chamber into the large-diameter first combustion cylinder, its diameter expands due to the swirling force. Mixing is promoted and the first
When it flows from the combustion tube through the first throttle into the second combustion tube, which has a large diameter, the diameter decreases and then expands due to its swirling force, promoting mixing.

Furthermore, since the air mixture is swirling, the stability of the air mixture is better than in the case where the air mixture is not swirling, and therefore, the stability of the flame is better.

However, in this spray type combustion device, the second combustion tube is thicker than the first combustion tube, and the combustion tube has an expanded tube structure with a thicker tip, so the flame becomes thicker at the tip, so when the fuel flow rate becomes small, Flame stability deteriorates, and combustion deteriorates due to flame fluctuations, backflow of exhaust gas, etc. In addition, in order to prevent backflow of exhaust gas, a second
A second restriction is required at the exit of the combustion tube.

That is, in a region where the fuel flow rate is very small, flame stability deteriorates and combustion deteriorates.

Further, in this spray type combustion device, the combustion cylinder has an expanded tube structure with a thicker end, and the body is thick, so the car heater, which is constructed by covering the body with a heat exchanger, becomes large.

That is, it is difficult to construct a small car heater.

An object of the present invention is to solve the conventional problems as described above.

Structure of the Invention A fuel injection valve that sprays liquid fuel from a closed end side to an open end side is provided concentrically in a cylindrical swirling chamber into which an air flow swirling around an axis is introduced. The structure is such that liquid fuel is sprayed at the center of the swirling airflow that has been introduced, an ignition plug is provided to ignite the mixture at the center of the mixed airflow in which the liquid fuel is sprayed into the swirling airflow, and a first throttle is installed at the open end of the swirling chamber. The first combustion tube is connected concentrically through the swirl chamber, the first combustion tube is formed to have a larger diameter or the same diameter as the swirl chamber, and the second combustion tube is connected to the outlet of the first combustion tube through a second throttle. A spray combustion device characterized in that the cylinders are concentrically connected and the second combustion cylinder is formed to have a smaller diameter or the same diameter as the first combustion cylinder.

Effect of the Invention When the air mixture flows from the swirling chamber through the first throttle into the first combustion cylinder having a large diameter or the same diameter, the diameter decreases and then expands due to the swirling force, promoting mixing and increasing the first combustion tube. When it flows from one combustion tube to a second combustion tube with a smaller diameter or the same diameter through a second throttle, the diameter decreases and then expands due to its swirling force, promoting mixing.

When the second combustion tube has a smaller diameter than the first combustion tube,
When the mixture flow flows from the first combustion tube to the second combustion tube, the speed increases, and the speed increase also promotes mixing.

Since the air mixture is swirling, the stability of the air mixture is good, and therefore the stability of the flame is good.

When the second combustion tube has a smaller diameter than the first combustion tube,
The flame becomes tapered and the flame stability is good. Therefore, reducing the fuel flow rate only shortens the length of the flame and does not cause the flame to become unstable. Furthermore, since the flame stability is good, even if there is no restriction at the outlet of the second combustion tube, the exhaust gas is less likely to flow back into the second combustion tube.

If the second combustion tube has the same diameter as the first combustion tube,
When the flow rate of the air mixture is larger than in the above case where the diameter is small, substantially the same effect as in the above case is achieved.

Effects of the Invention Even in a small fuel flow rate range, the flame does not become unstable, and there is little deterioration of combustion due to flame fluctuations, backflow of exhaust gas, etc.

The outlet of the second combustion tube does not require a restriction to prevent backflow of exhaust gas.

In addition, since the second combustion cylinder has a smaller diameter or the same diameter as the first combustion cylinder, and the body does not become thicker, when constructing a car heater by covering the body with a heat exchanger,
It is easy to construct a small car heater.

Next, examples of the present invention will be described.

First Example (See Figures 1 to 7) As shown in Figure 1, the spray combustion device of this example has a cylindrical shape formed in the center of a swirling airflow generating device 1, that is, a swirler 1. A fuel injection valve 11 sprays fuel into the swirling chamber 2 from the closed end side to the open end side thereof.
are provided concentrically, and a first aperture 1 is provided at the open end of the swirling chamber 2.
5, a cylindrical first combustion tube 16 is concentrically arranged, and an ignition plug 17 is provided at the axial position of the first combustion tube 16.
A cylindrical second combustion tube 2 is inserted into the outlet of the first combustion tube 16 through a second throttle 19.
0 are arranged concentrically.

The first combustion cylinder 16 is formed to have a larger diameter than the swirl chamber 2. The second combustion tube 20 is formed to have the same diameter as the first combustion tube 16. Note that no throttle is provided at the outlet of the second combustion cylinder 20.

As shown in FIGS. 1 and 2, the swirler 1 includes an inner circumferential wall 3 forming the circumferential wall of a swirling chamber 2, and the front and rear ends of a cylindrical outer circumferential wall 4 arranged concentrically around the outer circumferential position of the inner circumferential wall 3. A front end plate 5 and a rear end plate 6 are provided to form an annular air swirl path 7, and an air introduction pipe 8 is connected to one location on the outer peripheral wall 4 along the tangential direction of that location to form an air swirl path 7. An air introduction passage 8 connected to the passage 7 is formed, an air supply source 9 is connected to the air introduction passage 8, and air introduction holes 10 are formed at four locations on the inner circumferential wall 3 along the connecting direction of the inner circumferential surface of the respective locations. is installed through the shaft to connect the air swirling path 7 to the swirling chamber 2, so that an air flow swirling around the axis of the swirling chamber 2 is introduced into the swirling chamber 2.

As shown in FIG. 1, the fuel injection valve 11 has an injection end penetrated into the center of the rear end plate 6 of the swirling chamber, and the liquid fuel from the fuel supply passage 12 is injected into the air flow from the air supply passage 14. It is a two-fluid spray type that is atomized by atomization, and a fuel supply source 13 is connected to the fuel supply path 12, and an air supply source 9 is connected to the air supply path 14.

The ignition plug 17 connects the ignition part at the tip to the fuel injection valve 11.
ignition source 1 at the proximal terminal.
8 is connected.

Furthermore, the spray combustion device of the present invention has a combustion tube 1.
6 and 20 are fitted with a heat exchanger 21 to form a car heater.

As shown in FIGS. 1, 3, and 4, the heat exchanger 21 has a cylindrical container-shaped vessel body 22 fitted into the first combustion tube 16 and the second combustion tube 20, and the vessel body 22 and Between the first and second combustion tubes 16 and 20, the second combustion tube 2
A large number of heat exchange fins 24 are provided at equal intervals along the axial direction of the second combustion cylinder 20 on the inner circumferential surface of the vessel body 22. An outlet 25 of the gas passage 23 is provided in the first combustion cylinder 16 side portion of the gas passage 22 . The second combustion cylinder 20 side portion of the vessel body 22 is formed into a double container shape to form a fluid passage 26, and a spiral heat exchange fin 27 is provided on the inner circumferential surface of the fluid passage 26 to form a fluid passage 26. An inlet 28 and an outlet 29 are provided at one end of 26 and the other end. Note that a fluid supply source is connected to the inlet 28 of the fluid passage, and a radiator is connected to the outlet 29 of the fluid passage.

When the spray combustion device of this example is operated, the swirling chamber 2
An airflow is introduced that swirls around its axis,
Fuel such as light oil, kerosene, or gasoline is sprayed from the fuel injection valve 11 into the center of the swirling airflow in the swirling chamber 2, and the mixture flow of the sprayed fuel and swirling air flows into the swirling chamber 2.
flows into the first combustion tube 16 through the first throttle 15, is ignited by the spark plug 17 and burns, and the combustion flame flows from the first combustion tube 16 through the second throttle 19 to the second combustion tube 20. The combustion exhaust gas flows into the gas passage 23 from the second combustion cylinder 20, heats the heat exchange fins 24 and the vessel body 22 of the gas passage, and is discharged from the outlet 25. On the other hand, the inlet 28 of the fluid passage
Fluid such as water or air flows into the fluid passage 26, is heated by the heat exchange fins 27 of the fluid passage and the container body 22, reaches a high temperature, and flows out from the outlet 29.

The spray type combustion device of this example has a first throttle 15 provided between the swirl chamber 2 and the first combustion tube 16, and
6 is formed to have a larger diameter than the swirling chamber 2, so when the combustion flame of the air-fuel mixture flows from the swirling chamber 2 through the first throttle 15 and into the first combustion tube 16, its diameter is reduced and then due to the swirling force. Then, it suddenly expanded and the first combustion tube 1
6 and is uniformly distributed throughout the first combustion cylinder 16. Therefore, high load combustion becomes possible.

Further, due to the rapid expansion of the flame, a stable circulation region is formed in the first combustion tube 16, and the flame is well maintained. Therefore, the flame is stable even under a load of about 1/3 of the maximum load.

In addition, when the first combustion tube 16 is formed to have the same diameter as the swirling chamber 2, the diameter of the first throttle 15 is appropriately selected when the flow rate of the air-fuel mixture is larger than in the above case where the first combustion tube 16 is formed to have a large diameter. This produces almost the same effect as the above case.

In the spray type combustion apparatus of _this example _, as _shown in _FIG . When the diameter _D5 of the throttle 19: the diameter _L1 of the second combustion cylinder 20: the length of the swirling chamber 2, it is preferable to set the ratio as follows.

(1) When 0.6≦D ₂ /D ₁ ≦1 D ₂ /D ₁ <0.6, the sprayed fuel adheres to the first throttle 15 and flows down. Also, flame retention is not good.

(2) 0.5≦D ₄ /D ₃ ≦0.8 When D ₄ /D ₃ <0.5, the passage resistance from the first combustion tube 16 to the second combustion tube 20 becomes large, and the flame flow becomes unstable. When D ₄ /D ₃ >0.8, the aperture effect of the second diaphragm 19 is small.

(3) If 0.6≦D ₅ /D ₃ ≦1 D ₅ /D ₃ <0.6, the flame is in the second combustion tube 2.
0 too close to the peripheral wall of the second combustion tube 20.
passage resistance increases and combustion worsens.

(4) If 1≦D ₃ /D ₁ ≦2 D ₃ /D ₁ >2, the flame is in the first combustion tube 1.
6, and an extra space is created, which prevents it from being compact.

(5) 0.5≦L ₁ /D ₁ ≦1.5 When L ₁ /D ₁ <0.5, the distance required for the swirling airflow and the sprayed fuel to mix in the swirling chamber 2 is insufficient, and combustion deteriorates. When L ₁ /D ₁ >1.5, the sprayed fuel adheres to the peripheral wall of the swirling chamber 2, and more end-burning hydrocarbons are discharged.

(6) The total cross-sectional area of the air introduction holes 10 of the swirling chamber 2 is S ₀ ,
If the area of the peripheral wall of the swirling chamber 2 is S ₁ = π・D ₁・L ₁ , then 2≦S ₁ /S ₀ ≦100 If S ₁ /S ₀ >100, a swirling air flow is introduced into the swirling chamber 2. In order to do so, a high-pressure generator is required, which is large-scale and unsuitable for small-sized combustion devices. Also, the speed of the swirling airflow becomes too high,
On the contrary, mixing of the swirling air flow and the atomized fuel is hindered. When S ₁ /S ₀ <2, the speed of the swirling airflow is insufficient.

(7) Furthermore, if the protrusion length of the fuel injection valve 11 into the swirling chamber 2 is l, then O≦l≦L ₁ /2 Two-fluid spray in which the fuel injection valve 11 atomizes the fluid fuel by airflow In the case of this type, since the injection speed is high, a distance of L ₁ /2 or more is required in the swirling chamber 2 for sufficient mixing of the atomized fuel and the swirling air flow.

Next, in the spray fuel system of this example, D ₂ /D ₁ = 1, D ₃ /D ₁ = 1.5, D ₄ /D ₃ = 0.56, D ₅ /D ₃ = 1, L ₁ /D ₁ = 1. The performance is shown when S ₁ /S ₀ =47 and l=0.

6 and 7, the vertical axis shows the flow rate of air supplied to the swirler's air introduction path 8 and the fuel injection valve's air supply path 14, and the horizontal axis shows the fuel supply to the fuel injection valve. The flow rate of light oil, which is the fuel supplied to the road 12, is measured. In both figures, λ indicates the excess air ratio, ie the ratio of the supplied air flow rate to the theoretical air flow rate required for combustion. The left side of the hatched vertical line intersecting the λ=3 line indicates the region where the flame becomes unstable.

In Figure 6, CO is at the outlet 2 of the gas passage.
It shows the concentration of carbon monoxide in the exhaust gas discharged from No. 5. Therefore, as is clear from FIG. 6, the concentration of carbon monoxide in the exhaust gas is approximately 300 ppm or less in the range of 1.1≦λ≦2.2, which is very low.

Further, in FIG. 7, TE indicates the thermal efficiency of the car heater, that is, the 100% ratio of the amount of heat received by the water passing through the fluid passage 26 to the amount of heat generated by the supplied fuel. Therefore,
As is clear from FIG. 7, the thermal efficiency of the car heater is 85 to 95%, which is very high.

In the end, fuel with a minute flow rate of 1.2 to 6 c.c./min burns well. That is, the combustion range is a small range of fuel flow rate and is wide. In addition, the calorific value is 600
~3.000Kcal/h.

Second Embodiment (See FIGS. 8 to 11) As shown in FIG. A fuel injection valve 39 that sprays fuel from the closed end side to the open end side is provided concentrically in the swirling chamber 32, and a cylindrical first Combustion tube 44
The spark plugs 4 are arranged concentrically in a row, and the ignition plug 4 is installed in the first combustion cylinder 44.
A cylindrical second combustion tube 47 is concentrically connected to the outlet of the first combustion tube 44 via a second throttle 46.

The first combustion cylinder 44 is formed to have a larger diameter than the swirl chamber 32. The second combustion tube 47 is formed to have a smaller diameter than the first combustion tube 44.

As shown in FIGS. 8 and 9, the swirler 31 is
A front end plate 34 and a rear end plate 35 are provided at the front and rear ends of a cylindrical outer peripheral wall 33 arranged concentrically at the outer circumferential position of the swirling chamber 32 to form an annular air swirling path 36 . An air introduction pipe 37 is connected to one location along the connection direction of that location, and the air swirl circuit 3
6, a large number of guide vanes 38 are provided radially in the air swirling circuit 36 at equal intervals around the swirling chamber 32, and each guide vane 38 is located at a position where the inner ends thereof are close to each other. The air swirling path 36 is arranged along the connection direction of the circumferential surface of the swirling chamber 32, and the air swirling path 36 is communicated with the swirling chamber 32 through a gap between the guide vanes 38.
The structure is such that an air flow that swirls around the axis of the swirling chamber 32 is introduced into the swirling chamber 32.

As shown in FIG. 8, the fuel injection valve 39 has an injection end protruding into the swirling chamber 32 by more than half the length of the swirling chamber, and is attached to the center of the rear end plate 35 of the swirling chamber.
This is an ultrasonic vibration type in which the liquid fuel from the fuel supply path 40 is atomized by ultrasonic vibrations generated by two electrostrictive elements 42 holding an electrode 41 between them.

The ignition plug 45 connects the ignition part at the tip to the fuel injection valve 39.
located in the fuel spray area.

Furthermore, the spray combustion device of this example has a combustion tube 44,
47 is fitted with a heat exchanger 48 to form a car heater.

As shown in FIG. 8, FIG. 10, and FIG. 1, between the second combustion cylinders 44 and 47, the second combustion cylinder 4
A large number of heat exchange fins 51 are provided at equal intervals along the axial direction of the second combustion cylinder 47 on the inner peripheral surface of the vessel body 49, and a gas passage 50 is formed in communication with the outlet of the vessel body 49. An outlet 52 of a gas passage 50 is provided in the first combustion cylinder 44 side portion of the combustion chamber 49 . The vessel body 49 is
It is formed into a double container shape to form a fluid passage 53, a spiral heat exchange fin 54 is provided on the inner peripheral surface of the fluid passage 53, and an inlet 55 and an outlet 56 are provided at one end and the other end of the fluid passage 53. It is set up.

In the spray type combustion device of this example, since the second combustion tube 47 has a smaller diameter than the first combustion tube 44, the combustion flame of the air-fuel mixture passes from the first combustion tube 44 through the second throttle 46 to the second combustion tube 47. When the fuel flows into the air, the turning speed and forward speed are restored and increased, and the increased speed promotes the mixing of fuel and air. Also, the flame becomes tapered,
Improves stability. Therefore, combustion is performed well.

Further, since the fuel injection valve 39 is of the ultrasonic vibration type, the particle size of the sprayed fuel is small, and atomization is performed well. Furthermore, since the particles of the atomized fuel have a very small momentum during atomization, they are easily swept away by the swirling airflow, and are quickly mixed with the swirling airflow.

In addition, since the length of the fuel injection valve 39 protruding into the swirling chamber 32 is more than half the length of the swirling chamber, the fuel is injected into a stable swirling air flow, and there is little variation in the fuel-air mixture flow. The flame becomes stable. Further, the temperature of the fuel injection valve 39 is prevented from rising due to the swirling air flow around it, and the electrostrictive element 4, which is a source of vibration, is prevented from increasing in temperature.
2. Durability is improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of a spray combustion apparatus according to a first embodiment of the present invention. Figure 2 is the − of Figure 1.
FIG. FIG. 3 is a sectional view taken along the line -- in FIG. 1. FIG. 4 is a sectional view taken along the - line in FIG. 1. FIG. 5 is a partial longitudinal sectional side view of the same spray combustion device. FIG. 6 and FIG. 7 are diagrams showing the performance of the spray combustion device. Figure 8 shows the second
FIG. 2 is a longitudinal cross-sectional side view of the spray combustion device according to the embodiment. FIG. 9 is a sectional view taken along the - line in FIG. 8. 10th
The figure is a sectional view taken along the line -- in FIG. FIG. 11 is a sectional view taken along the line XI-XI in FIG. 8. 2: swirling chamber, 11: two-fluid spray type fuel injection valve,
15: First throttle, 16: First combustion tube, 17: Spark plug, 19: Second throttle, 20: Second combustion tube, 32:
Turning chamber, 39: Ultrasonic vibration type fuel injection valve, 43:
1st throttle, 44: 1st combustion tube, 45: Spark plug, 4
6: Second throttle, 47: Second combustion tube.

Claims (1)

[Claims] 1. A fuel injection valve that sprays liquid fuel from a closed end to an open end is provided concentrically in a cylindrical swirling chamber into which an air flow swirling around an axis is introduced. The structure is such that liquid fuel is sprayed at the center of the swirling air flow introduced into the swirling chamber, and an ignition plug is provided to ignite the center of the mixed air flow in which the liquid fuel is sprayed into the swirling air flow, and the open end of the swirling chamber is The first combustion tube is concentrically connected through a first throttle, the first combustion tube is formed to have a larger diameter or the same diameter as the swirl chamber, and the second combustion tube is connected to the outlet of the first combustion tube through a second throttle. A spray type combustion device characterized in that a second combustion tube is concentrically connected to each other, and the second combustion tube is formed to have a smaller diameter or the same diameter as that of the first combustion tube. 2. The spray according to claim 1, wherein the diameter of the first throttle is 0.6 times or more the diameter of the swirling chamber, and the diameter of the first combustion cylinder is not more than twice the diameter of the swirling chamber. type combustion device. 3 1.5 if the length of the turning chamber is 0.5 times or more the diameter of the turning chamber
The spray type combustion device according to claim 1 or 2, characterized in that the amount is less than or equal to twice as much. 4 The diameter of the second orifice is 0.5 times or more the diameter of the first combustion cylinder.
The spray combustion device according to any one of claims 1 to 3, characterized in that it is 0.8 times or less. 5. The spray combustion device according to any one of claims 1 to 4, wherein the diameter of the second combustion tube is 0.6 times or more the diameter of the first combustion tube. 6 The fuel injection valve is a two-liquid spray type that atomizes liquid fuel by airflow, and the length of the fuel injection valve protruding into the swirling chamber is 0.5 times or less the length of the swirling chamber. Claims 1 to 5
The spray-type combustion device according to any one of paragraphs. 7. The fuel injection valve is of an ultrasonic vibration type that atomizes liquid fuel by ultrasonic vibration, and the length of the fuel injection valve protruding into the swirling chamber is 0.5 times or less the length of the swirling chamber. A spray combustion device according to any one of claims 1 to 5.