JPH0218422B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a device for mixing air into fuel and combusting it, and more specifically, the above-mentioned fuel supply device that makes it easy to control the amount of air mixed in to a predetermined amount. Regarding.

(Prior Art) In order to improve combustion within a combustion chamber, a device has already been proposed that mixes air into fuel and injects it to combust it.

FIG. 1 shows an example of a previously proposed combustion device, which attempts to mix air in the form of microbubbles into fuel that is fed to an injection pump 2 of a diesel engine 1.

In the previously proposed device, the fuel in the fuel tank 3 is once boosted in pressure by the feed pump 4 and then fed.
A pipe 7 communicating with a compressor or an air tank 6 is opened into the pressurized fuel supply path 5, and compressed air is blown into the pressurized fuel from the tip of the pipe 7.

(Problems to be Solved by the Invention) The previously proposed structures as described above have the following drawbacks.

Since air is blown into pressurized fuel, the blown air must have a higher pressure than the fuel pressure. Therefore, a large-sized device such as a compressor or an air tank for producing or storing compressed air is required, which is undesirable in terms of cost and weight.

Furthermore, the amount of air blown into the fuel tank tends to fluctuate due to the influence of pulsations in fuel pressure, etc., making it difficult to always obtain a constant amount of blown air.

The present invention takes this one step further, and aims to make it easier to control the amount of air mixed in to a predetermined amount, and to simplify the device.

(Means for Solving the Problems) The present invention is characterized in that a mixing device such as a vent lily, an ejector, or an aspirator is provided in the fuel feeding route before the pressure is increased by the feeding pump, and a throat portion of the mixing device is provided. The idea was to open the tank to the atmosphere and allow air to be mixed in by suction.

(Example) The structure of the present invention, which improves the drawbacks of the previously proposed structure described above and brings it closer to practical use, will be described below with reference to FIG.

Note that since the present invention is also applied to continuous combustion devices, it should be noted in advance that the following description is not limited to diesel engines.

In the diesel engine 11, the fuel in the fuel tank 12 is pressurized by the feed pump 13, and the pressurized fuel is sent to the injection pump 1 through the feed path 14.
I am sending it to 5. The injection pump 15 is the injection pipe 1
6 to the injection valve 17 to inject the fuel into a combustion chamber (not shown).

It is desirable that the injected fuel mixes well with the air in the combustion chamber and burns completely, but in actual engines, sufficient air-fuel mixture cannot be obtained, and the exhaust gas contains a large amount of HC or smoke. will occur.

In the present invention, a return passage 18 communicating with the fuel tank 12 is provided in the feed route 14 ₂ downstream of the feed pump 13 , and an on-off valve 19 is provided in the return passage 18 .
will be established. Furthermore, a pressure detector 20 is provided in the feed path 14 ₂ downstream of the feed pump 13, and the opening/closing valve 19 is controlled to open and close based on the signal from the pressure sensor 20, thereby controlling the opening and closing of the on-off valve 19 within the feed path 14 ₂ . The pressure is controlled to a predetermined value. In this case, feeding route 14 ₂
When the internal pressure exceeds a predetermined value, the on-off valve 19 is opened and a portion of the fuel is returned to the fuel tank 12.

Further, a bench lily 21 is provided in the feeding path 14 ₁ upstream of the feeding pump 13 in the feeding path 14 . The bench lily 21 has a throat portion 22, and a plurality of small holes 23 are opened in the throat portion 22. The other end of the small hole 23 is open to the atmosphere.

The operation of the present invention configured as described above will be explained.

When the fuel fed to the feed pump 13 passes through the bench lily 21, air bubbles are mixed into the fuel through the small holes 23. The amount of air mixed in is determined by the degree of constriction of the throat portion 22, in other words, the amount of air mixed in
proportional to the flow rate of fuel passing through it.

The air-containing fuel is sent to the injection pump 15, where the pressure is further increased to a higher pressure, and the air bubbles are completely eliminated. And the injection valve 17
When the air is injected into the combustion chamber, air reappears and improves the combustion conditions.

Now, if the diesel engine 11 shifts from a high load to a low load, the amount of fuel required will decrease, and the fuel fed by the feed pump 13 will be in a surplus state. Therefore, the pressure within the feeding path 14 ₂ increases, and the pressure sensor 20 opens the on-off valve 19 . Then, a portion of the fuel is returned into the fuel tank, and the pressure within the feed path 14 ₂ is controlled to be constant, so that the flow rate through the throat portion 22 of the bench lily 21 is maintained constant. Therefore, in the device of the present invention, not only can a constant amount of mixed air be obtained at all times, but also the amount of mixed air can be controlled by changing the set value of the pressure detector 20.

Although the above description has been made regarding a diesel engine, the present invention can also be applied to continuous combustion devices such as gas turbine combustors and boilers. In the case of a gas turbine combustor, the feed pump shown in FIG. 2 may be replaced with a pump capable of boosting the pressure to a high pressure. Also, the injection pump can be eliminated from the boiler.

Incidentally, instead of the bench lily mentioned above, a structure having a suction function such as an ejector or an aspirator may be used, and the scope of the present invention includes all mixing devices having a suction function.

(Effects of the Invention) As explained above, according to the present invention, the amount of air mixed into fuel can be automatically controlled, and a complicated and large-sized device is not required.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of a previously proposed aeration device, and FIG. 2 is a system diagram showing an embodiment of the present invention. 11: Diesel engine, 12: Fuel tank, 13: Feeding pump, 15: Injection pump, 1
8: Return path, 19: Open/close valve, 20: Pressure detector, 21: Bench lily, 22: Throat part, 2
3: Small hole.

Claims (1)

[Scope of Claims] 1. In a combustion supply device that feeds fuel in a fuel tank by a feed pump, and injects and burns the fuel, the fuel is provided upstream of the feed pump in the fuel feed path. A mixing device is provided, a small hole communicating with the atmosphere is provided in the throat portion of the mixing device, a return path is provided downstream of the feed pump in the feed path, an on-off valve is provided in the return path, and a return path is provided downstream of the feed pump in the feed path. A pressure detector is installed in the downstream feed route, and when the pressure in the feed route downstream of the feed pump becomes higher than the set pressure, the on-off valve is opened, and the pressure in the feed route becomes higher than the set pressure. When the pressure becomes low, the on-off valve is closed to maintain the pressure in the feed route downstream of the feed pump at a predetermined level, and when the fuel flows through the throat of the mixing device, the pressure is A fuel supply device characterized in that a predetermined amount of air is mixed into the fuel. 2. In a diesel engine in which fuel in a fuel tank is fed to an injection pump by a feed pump, and the fuel is pressurized to a high pressure by the injection pump and injected into a combustion chamber through an injection pipe and an injection valve, A mixing device is provided upstream of the feeding pump in the fuel feeding path, a small hole communicating with the atmosphere is provided in the throat portion of the mixing device, and a return path is provided downstream of the feeding pump in the feeding path. , an on-off valve is provided in the return path, a pressure detector is provided in the feed path downstream of the feed pump, and the valve opens and closes when the pressure in the feed path downstream of the feed pump becomes higher than the set pressure. The valve is opened, and when the pressure in the feed route becomes lower than the set pressure, the on-off valve is closed to maintain the pressure in the feed route downstream of the feed pump at a predetermined level. A fuel supply device characterized in that a predetermined amount of air is mixed into fuel through small holes as it flows through a throat portion of a mixing device.