JPS6030407B2 - Air fuel ratio control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-fuel ratio control device that appropriately controls the mixture ratio of fuel and air supplied to a combustor of an external combustion engine, a combustion furnace for a dryer, or the like.

For example, in a combustor that is installed separately outside the main body, such as a Stirling cycle external combustion turbine, or in a device that supplies fuel to a combustion furnace such as a dryer, it is necessary to combine fuel and air to improve the combustion efficiency of the fuel. It is necessary to appropriately control the mixture ratio, that is, the air-fuel ratio.

For this reason, the fuel supply system is equipped with an air-fuel ratio control device that controls the amount of fuel supplied according to the amount of air supplied to the combustor so that the air-fuel ratio is always maintained within a certain range. . However, in conventional devices of this type, for example, in the case of a carburetor system, the amount of fuel supplied is controlled by a jet with a fixed diameter, so the amount of fuel supplied is controlled in response to sudden changes in the amount of intake air. The disadvantage is that the amount cannot be controlled in a follow-up manner.

In addition, fuel injection type systems detect the amount of intake air using an airflow sensor, etc., and then control the fuel injection pressure or injection nozzle diameter through electrical means, resulting in a complicated structure. There is a problem in that it is disadvantageous in terms of economy and maintenance. Therefore, in order to eliminate these drawbacks, devices with various structures have been proposed in which the fuel passage is throttle-controlled according to the intake air pressure and fuel injection pressure, but in all of them, the detection of the fuel flow rate is based on the secondary pressure. However, since the detection was only performed by the conventional method, it was not possible to expect satisfactory performance in terms of the degree of accommodation.

The present invention has been made in view of the above points, and includes an actuation valve that responds via a first pressure-receiving member according to the amount of intake air, and a fuel control valve that opens and closes a fuel supply passage by its operation. By applying fuel pressure to the second pressure-receiving member provided downstream of the valve and feeding back the balance force to the operating pestle, it is possible to adjust the air-fuel ratio with extremely high precision and eliminate excess air and incomplete combustion. The purpose of the present invention is to provide an air-fuel ratio control device that completely prevents combustion and improves combustion efficiency. Embodiments of the present invention will be described in detail below with reference to the drawings. The figure is a longitudinal cross-sectional view showing one embodiment of the air-fuel ratio control device according to the present invention. and fuel injected from the fuel injection nozzle 4 through the fuel supply path 3 extending through the tank 5, to generate a mixture having a predetermined air-fuel ratio, and combust it.

The intake pipe 2 is provided with a blower 6 at a downstream position.
Air is sucked in from the tip entrance and blown into the combustor 1.

Reference numeral 7 denotes a throttle provided at the tip of the intake pipe 2, which generates an appropriate negative pressure at a downstream position.

Further, reference numeral 8 denotes an air control valve that changes the closing area of the intake pipe 2 according to the rotational position, thereby controlling the amount of intake air. The intake pipe internal pressure P is located downstream of the throttle 7.
A tube 9 is disposed to lead out the air, and the intake pressure in the intake pipe is introduced into the first pressure receiving member 10 formed in a bellows shape. The proximal end 10a of the first pressure receiving member 1 is fixed to the device fixing part 11, and the movable end 10b on the opposite side is configured to be reciprocated by comparing the internal pressure with the atmospheric pressure. Furthermore, the movable end 10b of the first pressure receiving member 10 includes:
Connecting the other end 13a of the working village 13 with one end pivoted 12,
It is adapted to swing as the movable end 10b is displaced. On the other hand, a fuel pump 14 and a fuel control valve 1 are included in the fuel supply system 3 that connects the fuel tank 5 and the fuel injection nozzle 4.
5 is interposed.

The fuel control valve 15 has a pobet valve body 17 biased and supported in a valve chamber 16 by a spring 18. The povet valve body 17 closes the fuel supply passage 3 due to the biasing force of the spring 18, and the spring 1
By tilting the povet valve body 17 to the right in the figure against the force of 8, the fuel supply passage 3 is throttled or opened.

A second pressure-receiving member 19 in the form of a small-diameter bellows is provided at the left end of the povet valve body 17 to seal the fuel supply path 3, and a second pressure-receiving member 19 is provided at the left end of the povet valve body 17 to seal the fuel supply path 3. Place the left end of the povet valve body 17 on the outside of the operating village 1.
A pusher 21 fixedly installed in the middle of 3 is in contact with each other. In addition, due to the above-mentioned configuration, the fuel pressure downstream of the fuel control valve 15 is introduced into the second pressure receiving member 19, and the movable member 19a is displaced compared to atmospheric pressure. In the figure, 22 is a circle, and the symbols written in the figure are as follows.

Q^: Intake air amount QF: Supply fuel amount Po: Atmospheric pressure P^: Intake pipe internal pressure S,: Pressure receiving area of the first pressure receiving member S2: Pressure receiving area of the second pressure receiving member 1,: Pivot point and Distance 12 from the connection part of the pressure receiving member 1
: Distance between the pivot point and the connection part of the second pressure-receiving member 8 : Rotation angle R^ of the air control valve : Resistance of the throttle RF : Low resistance of the injection nozzle Since the present invention device has the above-mentioned configuration, its The effect is as follows.

First, the air control valve 8 is operated manually or automatically to adjust the amount of intake air.

Now, if the angle a of the air control valve 8 is made smaller, the intake air amount Q^ will increase and the intake pipe internal pressure P^ will become smaller than atmospheric pressure. Therefore, the first pressure receiving member 10 has a movable end 10b.
is displaced to the right in the figure, and the working village 13 is swung counterclockwise around the pivot point 12. This causes the pusher 21 to move to the second position.
Together with the pressure receiving member 19, the Pobet valve body 17 is pushed to the right in the figure against the force of the spring 18. This pressing force F is F=Harm-
SI(p^-P.

)...Represented by m.

On the other hand, fuel is being pumped into the valve chamber 16 by the pump 14, and as the Pobett valve element 17 opens the fuel supply path 3, the fuel flows and is injected from the injection nozzle 4.

At this time, the fuel downstream of the fuel control valve 15 is
Since the pressure is also supplied to the inside of the pressure receiving part village 19, the movable end 1
9a is displaced to the left in the figure and presses the operating punch 13 clockwise via the pusher 21. This pressing force F' is F'=
S2 (PF-P.

) ...{represented by 21. Therefore, when F=F', equilibrium is established, and the total amount of supplied fuel QF is controlled according to the opening degree of the fuel control valve at that time.

Here, from the general formula for calculating the flow rate, Q = C no △P, as a simplified formula, QA = Quantity.・・・．・・【3'QF
=Tokyocho City ．・・・． ...Leading '41.

Note that PT in formula (■) is the pressure inside the furnace, but considering the nozzle diameter and fuel injection pressure, it is assumed that PT = Po, and the formula '4) is changed to QF = pressure in the furnace.・・・．・On the other hand, from F=F′ mentioned above, '1}, {2)
Using the formula, S2(PF-P.

)=Harm-S・(P^-P.)...■, so if we substitute the formula (3}, {4) into this, we get QF=Umano;Thing-Q^
b7] can be obtained.

As can be seen from this equation {7}, the fuel supply amount QF is obtained as a value proportional to the intake air amount Q^.

Further, the fuel supply amount QF can be controlled by the ratio of 1, , 12, the ratio of S, , S2, and further by the resistances R^ and RF, and the air-fuel ratio can be changed by changing these values. In particular, since the ratio of the lengths 1, 12 of the operating punch 13 can be easily changed, it is optimal for changing and setting the air-fuel ratio. As is clear from the above description, according to the present invention, the air-fuel ratio control device includes an operating pestle that responds via the first pressure-receiving member according to the intake air amount, and a fuel control valve that opens and closes the fuel supply passage by the operation of the operating pestle. By applying fuel pressure to a second pressure-receiving member provided on the downstream side of the fuel control valve and feeding back the balance force to the operating village, the relationship of the fuel control valve to the air flow rate can be adjusted. Proportional fuel flow rates are automatically maintained, allowing the fuel/air mixture ratio to be automatically adjusted with extreme precision to completely avoid excess air and incomplete combustion. , significantly improving combustion efficiency.

Further, since only a throttle is provided to operate the operating punch according to the amount of intake air, the shape of the intake passage can be made straight, and the design and processing can be significantly simplified.

[Brief explanation of drawings]

The figure is a longitudinal sectional view showing an embodiment of an air-fuel ratio control device according to the present invention. 1... Combustion furnace, 2... Intake pipe, 3...
...Fuel supply path, 4...Fuel injection nozzle,
5...tank, 6. ．． ...Blower, 7...
... Throttle, 8... Air control valve, 10...
...First pressure receiving part village, 13......Operating village, 15
...Fuel control valve, 17...Pobet valve body,
19...Second pressure receiving village, 21...Pusher.

Claims (1)

[Claims] 1. A first pressure receiving member that introduces pressure downstream of an intake throttle provided in the intake air passage and displaces its movable end at an atmospheric pressure ratio;
An operating rod that responds to the displacement of the first pressure-receiving member, a fuel control valve that is operated by the operating rod to open, close, or throttle the fuel supply path leading to the fuel injection nozzle, and a downstream of the fuel control valve. An air-fuel ratio control device comprising: a second pressure-receiving member which introduces fuel pressure from the side and whose one end is displaced at an atmospheric pressure ratio to apply a balancing force to the operating rod.