JPH08193550A - Gas-liquid mixer of diesel engine - Google Patents

Abstract

PURPOSE: To prevent an uninjected state from occurring through a simple structure, pertaining to this a gas-liquid mixer of a diesel engine to treat air mixed in a fuel supply system. CONSTITUTION: In this gas-liquid mixer of a diesel engine, made up of installing a fuel filter 3 and a fuel injection pump 4 in order in a fuel supply system ranging from a fuel tank 2 to a fuel injection nozzle 5, this mixer 1, which forms a flow of air containd in fuel to be conveyed into granules, and supplies this finely granulated fuel inclusive of air toward the fuel injection pump 4, is installed in space between the fuel filter 3 and the fuel injection pump 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid mixing device for a diesel engine, and more particularly to a gas-liquid mixing device for a diesel engine for treating air mixed in a fuel supply system.

[0002]

2. Description of the Related Art Generally, a fuel supply system of a diesel engine is provided with a fuel filter and a fuel injection pump in order between a fuel tank and a fuel injection nozzle. By the way, the fuel flowing through the fuel supply system may contain a large amount of bubbles (air), and if this flows into the fuel injection pump as it is, the flow of fuel becomes an intermittent flow and a non-injection state occurs. As a result, the injection characteristics of the fuel injection amount and the like change, causing a malfunction of the diesel engine. Therefore, various devices for treating the air mixed in the fuel have been proposed.

An example of an apparatus for treating the air mixed in the fuel is disclosed in Japanese Patent Laid-Open No. 157014/1993. The device for treating mixed air disclosed in the publication includes a bubble discharge device provided between a fuel filter and a fuel injection pump and having a bubble separation film for capturing air (bubbles) in the fuel, and the bubble separation device. It is configured to have a space formed above the membrane, a return passage having a venturi portion inside the space for passing the surplus fuel, and a communication passage connecting the space and the venturi portion.

In the above structure, a negative pressure is generated in the venturi portion by the flow of the return fuel flowing through the return passage. Further, the air captured by the bubble separation membrane will be accumulated in the space formed above the bubble separation membrane. Furthermore, since the space and the venturi section are communicated with each other by the communication passage, the air accumulated in the space is sucked through the communication passage due to the negative pressure generated in the venturi portion and flows into the return fuel flowing through the return passage. Therefore, it is configured to be returned to the fuel tank.

[0005]

By the way, in a fuel supply system having a so-called distribution type fuel injection pump, in which fuel is distributed from the fuel injection pump to each fuel injection nozzle, the fuel injection pump is a diesel engine. It is configured to be driven by a crankshaft. Therefore, the fuel injection pump is generally arranged at a lower position of the diesel engine. Further, since the fuel filter is a device having a relatively large outer shape, it cannot be set under the fuel injection pump.

Therefore, the fuel filter is located above the fuel injection pump, and since the air mixed in the pipe is lighter than the fuel, it easily accumulates in the fuel filter located above or in the pipe located above, and a fixed amount. At the time of accumulation, air mixes with the fuel flow and temporarily flows into the fuel injection pump in large quantities. At this time, the fuel flow becomes an intermittent flow and a non-injection state occurs, which causes a malfunction of the diesel engine.

As described above, there are restrictions on the positions where the fuel filter and the fuel injection pump are arranged. Further, since the bubble discharging device needs to introduce the return fuel from the fuel injection pump, it must also be arranged in the vicinity of the fuel injection pump. On the other hand, the lower part of the diesel engine is a part where the injection pump constituent devices such as a timer device, electrical components and the like are arranged at high density, and there is little surplus space.

However, in the above-mentioned conventional device, since the air accumulated in the space inside the bubble discharging device is returned to the fuel tank through the return passage, it is necessary to provide the return passage and the structure becomes complicated. There is a problem. Further, there is a problem that the return passage and the bubble discharging device must be provided in a portion where the surplus space is small, and it is difficult to set the arrangement positions of the return passage and the bubble discharging device.

The present invention has been made in view of the above points, and prevents generation of an intermittent flow without providing a return passage by atomizing the air contained in the fuel and supplying it to the fuel injection pump. However, it is an object of the present invention to provide a gas-liquid mixing device for a diesel engine that can prevent the occurrence of a non-injection state with a simple configuration.

[0010]

In order to solve the above problems, the present invention relates to a diesel engine in which a fuel filter and a fuel injection pump are sequentially arranged in a fuel supply system from a fuel tank to a fuel injection nozzle. In the gas-liquid mixing device, an air atomizing means for atomizing the air contained in the conveyed fuel is provided between the fuel filter and the fuel injection pump.

[0011]

With the above-mentioned structure, the air contained in the fuel conveyed by the air atomizing means is atomized and supplied to the fuel injection pump. Here, the non-injection state occurs because a large amount of air is temporarily supplied to the fuel injection pump, and fuel mixed with atomized air is continuously supplied to the fuel injection pump. In the state of flowing into the engine, the non-injection state does not occur and the operation of the diesel engine is not hindered.

Therefore, the air contained in the fuel is atomized by the air atomizing means, and the fuel containing the atomized air is supplied to the fuel injection pump to prevent the non-injection state from occurring. Therefore, the operation of the diesel engine can be improved. Further, since the air contained in the fuel is atomized and supplied to the fuel injection pump, it is not necessary to provide a return pipe, so that the structure near the position where the fuel injection pump is disposed can be simplified and the number of parts can be reduced. be able to.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a fuel supply system of a diesel engine provided with a gas-liquid mixing device 1 according to an embodiment of the present invention. First, the overall configuration of the fuel supply system of the diesel engine will be described.

As shown in FIG. 1, the fuel supply system of a diesel engine is roughly divided into a gas-liquid mixing device 1, a fuel tank 2, a fuel filter 3, a fuel injection pump 4, and a fuel injection nozzle 5 (corresponding to the number of cylinders. Image provided in the same way, 1 in the figure
(Only one is shown in the figure) and the like.

The fuel tank 2 has an in-tank
It has a filter 6 and a suction pipe 7, and is connected with a fuel supply pipe 8 and a reflux pipe 9. The in-tank filter 6 is connected to the fuel supply pipe 8 and has a function of preventing dust (relatively large dust) in the fuel tank 2 from entering the fuel supply pipe 8. The in-tank filter 6 is arranged near the bottom of the suction pipe 7.

The fuel filter 3 has a structure in which a filter element is provided inside a filter case, and has a function of removing fine dust mixed in the inflowing fuel. Since the fuel filter 3 has a relatively large shape, it cannot be arranged below the fuel injection pump 4.
Therefore, the fuel filter 3 is arranged at a position higher than the position where the fuel injection pump 4 is arranged.

The fuel injection pump 4 includes a drive shaft 4
a is connected to a crankshaft of a diesel engine (not shown) and is driven by the driving force of the diesel engine. A feed pump (not shown) is disposed inside the fuel injection pump 4, and the suction force generated by the feed pump causes the fuel in the fuel tank 2 to be sucked toward the fuel injection pump 4.

The sucked fuel is increased in pressure by a high-pressure pump mechanism arranged in the fuel injection pump 4, and is distributed at a predetermined timing to the fuel injection nozzles 5 arranged in each cylinder of the diesel engine. It is configured to be pumped. Since the fuel injection pump 4 is configured to be driven by the crankshaft of the diesel engine as described above, it is arranged at the lower position of the diesel engine.

The fuel injection nozzle 5 is connected to the fuel injection pump 4 as described above, and when high-pressure fuel is supplied from the fuel injection pump 4, the valve is opened at a predetermined fuel pressure, and the fuel is injected into the cylinder. Is configured to be jetted. The fuel supply system including the above-described components includes a fuel supply pipe 8 from the fuel tank 2 to the fuel injection nozzle 5, and a fuel filter 3, a gas-liquid mixing device 1, and a fuel injection pump 4 in order from the fuel tank 2 side. It is arranged.

In the fuel supply system configured as described above, the fuel sucked from the fuel tank 2 via the in-tank filter 6 and the suction pipe 7 flows in the fuel supply passage 8 in the direction of the solid line arrow, After passing through the fuel filter 3 and the gas-liquid mixing device 1 which is a main part of the present invention, the fuel is supplied to the fuel injection pump 4 and is distributed and pressure-fed to each fuel injection nozzle 5 from here.

Further, the nozzle surplus fuel not injected from the fuel injection nozzle 5 and the pump surplus fuel in the fuel injection pump 4 pass through the recirculation passage 9 as shown by the broken line arrow in FIG. It is configured to return to 2. Next, the gas mixing apparatus 1 which is the main part of the present invention will be described with reference to FIG. 2 in addition to FIG.

The gas mixing device 1 is arranged between the fuel filter 3 and the fuel injection pump 4 in the fuel supply pipe 8 as described above. This gas mixing device 1 is roughly composed of a housing 10, a separator 11, an air introduction passage 12,
And the air bleed 13 and the like.

The housing 10 is a closed container having a cylindrical shape, and an inflow port 14 and an outflow port 15 are formed at the upper position. The inflow port 14 is connected to the fuel filter 3 via the fuel supply pipe 8, and the outflow port 15 is connected to the fuel injection pump 4 via the fuel supply pipe 8.

The top plate 1 is provided inside the housing 10.
Separator 11 provided so as to hang downward from 0a
Is provided. By disposing the separator 11, the interior of the housing 10 is divided into a gas-liquid separation chamber 16 and a gas mixing chamber 17.

The separator 11 is the housing 1
0 does not extend to the bottom surface 10b, and the separator 11
The lower end 11a and the bottom surface 10b are separated by a predetermined distance. This separated portion forms a fuel passage 18 through which fuel flows from the gas-liquid separation chamber 16 to the gas mixing chamber 17.

An air introduction passage 12 is formed on the surface of the separator 11 on the gas-liquid separation chamber 16 side. The air introduction passage 12 is formed by a passage wall 19 having a substantially L-shaped cross section as shown in the drawing, and the air introduction passage 12 is opened to the gas-liquid separation chamber 16 at a position near the top plate 10a. It is said that.

The air bleed 13 is used as the separator 1.
A small hole is formed in the vicinity of the lower end of No. 1 so as to penetrate therethrough, and its diameter is, for example, about 0.3 mm. By forming the air bleed 13, the gas mixing chamber 17 and the air introduction passage 12 are communicated with each other.

Subsequently, the gas mixing apparatus 1 having the above structure
The operation will be described below. When the feed pump provided in the fuel injection pump 4 performs the suction operation, the fuel tank 2 is introduced into the inflow port 14 of the gas mixing device 1 via the in-tank filter 6, the fuel filter 3, and the fuel supply pipe 8. The fuel loaded in the tank flows in. On this occasion,
A large amount of air is temporarily mixed in the fuel flowing into the gas mixing device 1.

That is, also in the fuel supply system in which the gas mixing device 1 according to this embodiment is installed, the installation position of each device constituting the fuel supply system is restricted, and specifically, the fuel injection pump 4 is used. Needs to be arranged at a lower position of the diesel engine, and the fuel filter 3 needs to be arranged above the fuel injection pump 4. Therefore, the air mixed in the fuel supply passage 8 is likely to be accumulated in the fuel filter 3 or the portion located above the fuel supply pipe 8, and when a certain amount of the air is accumulated, the air is mixed in the fuel flow and temporarily. A large amount of gas flows into the gas mixing device 1.

When the fuel mixed with a large amount of air flows into the inlet 14, the fuel first flows into the gas-liquid separation chamber 16 connected to the inlet 14.
At this time, since the air is lighter than the fuel, the air and the fuel are separated, and the air is located above the gas-liquid separation chamber 16 and the fuel is located below the gas-liquid separation chamber 16. That is, in the gas-liquid separation chamber 16, air and fuel are separated into gas and liquid.

On the other hand, the outlet 15 is connected to the fuel injection pump 4, so that the suction force generated by the fuel injection pump 4 is applied to the outlet 15. Due to this suction force, the fuel located in the lower part of the gas-liquid separation chamber 16 advances into the gas mixing chamber 17 through the fuel passage 18 (the flow of fuel is indicated by the solid arrow in the figure).

At this time, the air mixed with the fuel is gas-liquid separated as described above and is located above the gas-liquid separation chamber 16, so that it enters the gas mixing chamber 17 through the fuel passage 18. There is no such thing. However, the air accumulated in the upper part of the gas-liquid separation chamber 16 has a predetermined pressure as fuel is sequentially introduced from the inflow port 14, and therefore the air having the predetermined pressure is not separated by the separator 11.
Flowing into the air introduction passage 12 arranged on the gas-liquid separation chamber 16 side.

As described above, the air introduction passage 12 is configured to open to the gas-liquid separation chamber 16 in the vicinity of the top plate 10a. Will not penetrate inside. Therefore, only air flows into the air introduction passage 12.

The air that has flowed into the air introducing passage 12 is arranged in the lower portion of the air introducing passage 12 and the air bleed 13 is provided.
Leading to. Since the air bleed 13 is a hole that connects the gas-liquid separation chamber 16 and the gas mixing chamber 17, the air that has flown into the air bleed 13 is the air bleed 1.
3 and flows into the gas mixing chamber 17.

At this time, as described above, the suction force generated by the fuel injection pump 4 acts on the gas mixing chamber 17, so that the fuel fills the gas mixing chamber 17. Therefore, the air blown from the air bleed 13 toward the gas mixing chamber 17 is mixed with the fuel in a state where the gas mixing chamber 17 is filled. Further, as described above, the diameter of the air bleed 13 is
Since it is a small hole of about 0.3 mm, the air blown out is in a finely divided state, so that the finely divided air is mixed with the fuel in the gas mixing chamber 17.

The fuel mixed with the air thus atomized is introduced into the fuel injection pump 4 through the outlet 15. Here, the fuel injection nozzle 5 is in the non-injection state when a large amount of air temporarily flows into the fuel injection pump 4. However, in the configuration in which the fuel mixed with the atomized air is supplied to the fuel injection pump 4 and the pressure of the fuel is increased by the fuel injection pump 4 and injected from the fuel injection nozzle 5 as in the present embodiment, the air is It is dispersed in the fuel because it is made finer. Therefore, an intermittent flow does not occur on the upstream side of the gas-liquid mixing device 1 with respect to the fuel flow direction, and thus the fuel injection nozzle 5 can be prevented from becoming a non-injection state. Therefore, the diesel engine can always be operated in a stable state.

Further, the gas-liquid mixing apparatus 1 does not have a structure in which the air generated in the fuel supply system is returned to the fuel tank 2 unlike in the conventional case, but the generated air is atomized to be discharged from the fuel injection nozzle 5. Since it is configured to eject, it is not necessary to connect the reflux pipe 9 to the gas-liquid mixing device 1.

As a result, the position where the reflux pipe 9 is arranged can be set regardless of the gas-liquid mixing apparatus 1, so that the position where the reflux pipe 9 is arranged can be set freely. Further, since it is not necessary to dispose the gas-liquid mixing device 1 in the vicinity of the fuel injection pump 4, it is possible to give flexibility to the setting position of the gas-liquid mixing device 1. Therefore, the layout with the constituent elements of the diesel engine is facilitated, and the fuel supply system and the diesel engine as a whole can be made compact.

In the above embodiment, the air bleeding 13 which is a small hole is formed in the separator 11 provided in the gas-liquid mixing device 1 as the air atomizing means. The means for granulating is not limited to this, and it goes without saying that another configuration may be used as long as it can granulate the air.

[0040]

As described above, according to the present invention, the air atomizing means is used to atomize the air contained in the fuel, and the fuel containing the atomized air is supplied to the fuel injection pump. As a result, the occurrence of the non-injection state can be prevented, and the operation of the diesel engine can be improved.

Further, since the air contained in the fuel is atomized and supplied to the fuel injection pump, it is not necessary to provide a return pipe, so that the structure near the position where the fuel injection pump is arranged is simplified and the number of parts is reduced. It is possible to reduce.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an overall configuration of a fuel supply system provided with a gas-liquid mixing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a gas-liquid mixing device that is an embodiment of the present invention.

[Explanation of symbols]

 1 Gas-Liquid Mixing Device 2 Fuel Tank 3 Fuel Filter 4 Fuel Pump 5 Fuel Injection Nozzle 8 Fuel Supply Pipe 9 Recirculation Pipe 10 Housing 11 Separator 12 Air Introduction Passage 13 Air Breed (Small Hole) 16 Gas-Liquid Separation Chamber 17 Gas Mixing Chamber 18 Fuel passage 19 Passage wall

Claims (1)

[Claims] 1. A gas-liquid mixing apparatus for a diesel engine, wherein a fuel filter and a fuel injection pump are arranged in order in a fuel supply system from a fuel tank to a fuel injection nozzle, wherein a fuel filter and a fuel injection pump are provided. A gas-liquid mixing device for a diesel engine, characterized in that an air atomizing means for atomizing the air contained in the conveyed fuel is provided therebetween.