JPS58143154A - Carburetor - Google Patents

Abstract

PURPOSE:To make the fuel in a proper mixture ratio feedable to an engine, by varying the effective sectional area of a fuel jet which is formed so as to make its pressure at the inlet side constant at all times. CONSTITUTION:Fuel from a float chamber 11 is led into a fuel jet 9 via a fuel intake passage 10 and thereby the pressure at the inlet side of the fuel jet 9 is always kept constant. An intake air stream detecting plate 4 being eccentrically secured to a rotary shaft 3 detects the quantity of the intake air stream but simultaneously shifts a metering needle 8 via a lever 7 secured to the rotary shaft 3, altering the effective sectional area of the fuel jet 9 in response to the air flow and metering the fuel consumption, and then this metered fuel is discharged to an atmospheric chamber 12. This fuel is spouted into an intake air passage 1 and makes up a proper mixture ratio required by the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carburetor for an internal combustion engine in which atomization of fuel is promoted by a high-speed airflow of intake air fed under pressure from a pump.

Generally, the fuel supplied to the engine is measured and measured by a carburetor.
However, increasing the intake flow velocity in the carburetor (Venturi part) to promote fuel atomization will result in an obstacle that further increases the intake resistance. The degree of fuel consumption was unavoidably poor, which was unsatisfactory from the engine's point of view, and as a result, the fuel distribution to each cylinder, the engine's fuel efficiency, and exhaust gas characteristics were degraded.

The present invention is an attempt to solve the above-mentioned drawbacks by significantly promoting atomization of fuel by using a high-speed airflow of intake air fed under pressure from a pump, and will be described below with reference to the drawings.

FIG. 1 shows a carburetor according to the present invention, which is equipped with a pump 17 driven by an engine output shaft, an electric motor, etc. (a small-capacity pump may be used).

The diameter of the atmospheric chamber 12 is sufficiently large compared to the diameter of the communication passage 13 (usually, as shown in the figure, since a part with the smallest diameter is formed in the communication passage 13, compared to the diameter of this part). Therefore, regardless of the strength of the negative pressure acting on the communication path 13 (even if strong negative pressure acts), the pressure in the atmospheric chamber 12 is always maintained at atmospheric pressure.

On the other hand, the fuel from the float chamber 11 is introduced into the fuel jet 9 via the fuel introduction passage 10, so that the pressure on the inlet side of the fuel jet 9 is always constant (the height of the fuel oil level in the float chamber 11). is always constant).

(When a large amount of fuel begins to flow through the fuel introduction passage 10,
Strictly speaking, the pressure on the inlet side of the fuel jet 9 will change slightly depending on the fuel flow rate, but since the diameter of the fuel introduction passage 10 is normally set to be sufficiently large, generally the pressure on the inlet side of the fuel jet 9 will change slightly depending on the fuel flow rate. pressure is assumed to be constant).

Therefore, by changing the effective cross-sectional area (the effective cross-sectional area through which fuel passes) of the fuel jet 9 (as appropriate) in accordance with the intake flow rate flowing through the intake passage 1 of the carburetor, the proper mixture ratio can be supplied to the engine. The matter is clear.

For this purpose, an intake flow rate detection plate 4 is provided eccentrically fixed to the rotating shaft 3.

That is, when the intake air passes through the intake passage 1, the intake flow rate detection plate 4 receives a valve opening torque due to the pressure difference before and after the intake passage 1, and this valve opening torque and the intake flow rate detection plate 4 are subject to a predetermined closing force applied by a spring or the like. It is opened to an opening that balances the torque, and the intake flow rate is detected.

At the same time, a metering needle 8 is moved via a lever 7 fixed to the rotary shaft 3 to change the effective cross-sectional area of the fuel jet 9 and meter the fuel, which flows out into the atmospheric chamber 12.

The fuel that has flowed out into the atmospheric chamber 12 further passes through the communication passage 13 (is sucked up) and is ejected from the nozzle 14 (forming a part of the communication passage 13) into the intake passage 1, thus achieving the proper conditions required by the engine. Form the mixing ratio.

The pressure of the intake air pumped from the pump 17 is a positive pressure, but when the intake air is jetted out at high speed from the intake nozzle 15, it is first reduced to ambient pressure, and then further reduced by its own velocity energy ( Therefore, the fuel flowing out from the fuel jet 9 can be sucked up through the connecting path 13.

At this time, since the speed of the intake air jetted out from the intake nozzle 15 is extremely high, the fuel jetted out from the nozzle 14 is atomized very well.

Therefore, the distribution of the fuel chamber to each cylinder is improved, vaporization is promoted, and complete combustion of the fuel becomes possible, so that the fuel efficiency and exhaust gas characteristics of the engine are significantly improved.

In this case, if the pump discharge side passage 16 is actively heated with exhaust gas, an electric heater, etc., high temperature intake air will be ejected from the intake nozzle 15, which will be even more effective.

5 is a damper plate, and 6 is a damper chamber that stabilizes the operation of the intake air inflow detection plate 4.

In the present invention, when fuel supply is not required, such as when the engine is stopped, the fuel introduction passage 10 is closed by the cutoff valve 18 (in the figure, an electromagnetic cutoff valve is used) shown by the chain double-dashed line, and the fuel from the fuel jet 9 is removed. Atmospheric chamber 12
It is desirable to avoid a large amount of fuel from accumulating in the tank.

Incidentally, the fuel flowing out from the fuel jet 9 is transferred to the float chamber 1.
The fuel is jetted into the intake passage 1 of the carburetor after passing through a place higher than the oil level of the fuel oil, but the nozzle 14' (i.e.,
It is also conceivable to eject it from the float chamber 11 (located below the fuel oil level) and collide with the high-speed airflow of intake air pumped from the pump 17 to atomize it (in this case, In order to indicate that fuel supply is not required, it is necessary to prevent the fuel from flowing out from the fuel jet 9 using the shutoff valve 18).

According to this method, the distance of the connecting path 13' can be shortened, so the responsiveness of the engine is extremely improved. ).

Reference numeral 15' denotes an intake nozzle through which intake air pumped from the pump 17 is jetted out.

Next, the intake flow rate detection plate 4 that detects the intake flow rate is connected to the plate valve 1.
FIG. 2 shows an embodiment of the present invention in which the intake air flow rate detection diaphragm device 9 and the intake air flow rate detection diaphragm device 22 are replaced.

That is, in FIG. 2, the plate valve 19 has the rotating shaft 3 at its center.
is fixed and rotatable about the rotating shaft 3, and the negative pressure generated downstream of the plate valve 19 is introduced into the intake flow rate detection diaphragm device 22.

Therefore, when the intake air passes through the intake passage 1, the intake flow rate detection diaphragm device 22 applies a valve opening torque to the rotary shaft 3 via the rod 21 and the lever 20, and also applies the valve opening torque to the plate valve 19 ( That is, the plate valve 19 is opened to an opening degree that balances the closing torque given in advance to the rotating shaft 3, and the air flow rate is detected.

At the same time, a metering needle (not shown) is moved via lever 7 to vary the effective cross-sectional area of the fuel jet (not shown) and meter the flow rate, thus achieving the engine's demand as in Figure 1. Form a proper mixing ratio.

Next, an embodiment of the present invention shown in FIG. 3 will be described.

That is, in FIG. 3, the intake air that is force-fed from the pump 17 is ejected into the jetting passage 24 through the constriction part 23, and even if the pressure immediately before the constriction part 23 is positive, the constriction part 23 As the intake air passes through at a high speed, the pressure is reduced, and a negative pressure is applied to the communication passage 13 that opens to the constriction part 23.

As a result, the fuel flowing out from the fuel jet 9 is guided to the jetting passage 24 through the communication passage 13, and is further jetted out violently from the jetting part 25 (which forms a part of the jetting passage 24), resulting in an extremely smooth flow. This results in atomization.

Therefore, the distribution of fuel to each cylinder and the fuel and exhaust gas characteristics of the engine are greatly improved.
It will be even more effective if you make it collide with 5).

At this time, since the intake air pressure-fed from the pump 17 passes through the injection passage 24, the fuel and intake air in the injection passage 24 flow at an extremely high speed, and therefore the fuel jet 9
Since the fuel flowing out from the intake passage 1 is jetted out into the intake passage 1 more quickly, the response of the engine is improved (it is desirable to make the communication passage 13 as short as possible).

If the discharge pressure of the pump 17 is quite high, increase the pressure loss by lengthening the pump discharge side passage 16 or installing a resistor inside it to reduce the pressure immediately before the constriction part 23 as much as possible. It is preferable to lower the pressure, so that a strong negative pressure can be applied to the communication path 13.

4 is an intake flow rate detection plate, 8 is a motoring needle, 9 is a fuel jet, and 12 is an atmospheric chamber, and their functions are as explained in FIG. 1.

Incidentally, the fuel that has passed through the communication path 13 and the throttle section 23 is sent to the jet section 25' located downstream of the throttle valve 2 as shown by the two-dot chain line.
The air may be ejected from the air inlet (which forms part of the ejection passage 24') into the intake passage 1.

In this case, since the jetting portion 25' is located at a lower level than the fuel oil level in the float chamber 11, the outflow of fuel from the fuel jet 9 is prevented by the shutoff valve 18 shown by the two-dot chain line when fuel supply is not required. is necessary.

As described above, the present invention provides an intake flow rate detection device (an intake flow rate detection plate, a plate valve, and an intake flow rate detection diaphragm device) that is equipped with a fuel jet whose pressure on the inlet side is always constant, and that operates according to the intake flow rate. etc.), the effective cross-sectional area of this fuel jet is changed to measure the fuel, and the fuel from the fuel jet is flowed out into an atmospheric chamber where atmospheric pressure acts, and then passed through a communication passage, and this fuel is Since the fuel is supplied by colliding with the high-speed airflow of intake air pumped from the pump, it is possible to greatly improve the distribution of fuel to each cylinder, the fuel efficiency of the engine, and the exhaust gas characteristics.

It should be noted that the pump in the present invention does not need to be dedicated to filtering fuel into fine particles, and may be a pump provided for other purposes (for example, to inject air into exhaust gas for exhaust gas purification). pump).

[Brief explanation of drawings]

1 and 3 are cross-sectional views of a carburetor according to the present invention, and FIG. 2 is a diagram of an intake air flow rate detection device. 1 is an intake passage of the carburetor, 2 is a throttle valve, 3 is a rotating shaft, 4 is an intake flow rate detection plate, 5 is a damper plate, 6 is a damper chamber, 7.
20 is a lever, 8 is a metering needle, 9 is a fuel jet, 10 is a fuel introduction passage, 11 is a float chamber, 12
is an atmospheric chamber, 13 and 13' are connecting passages, 14 and 14' are nozzles, 15 and 15' are intake nozzles, 16 is a pump discharge side passage, 17 is a pump, 18 is a cutoff valve, 19 is a plate valve, and 21 is The rod, 22 is an intake flow rate detection diaphragm device, 23 is a constriction part, 24 and 24' are jet passages, and 25 and 25' are jet parts. Patent applicant Shuichi Kitamura

Claims (4)

[Claims] (1) The fuel jet is equipped with a fuel jet whose inlet side pressure is always constant, and the effective cross-sectional area of the fuel jet is varied by an intake flow rate detection device that operates according to the intake flow rate to measure the fuel. Furthermore, after the fuel from the fuel jet flows out into an atmospheric chamber where atmospheric pressure acts, it is made to pass through a communication passage and collide with the high-speed airflow of intake air pumped from this fuel pump, thus supplying fuel. A vaporizer characterized by the following features: (2) The fuel that has passed through the communication path collides with the high-speed airflow of intake air that is force-fed from the pump, and the fuel is further jetted out through the jetting passage, thus supplying fuel. Vaporizer described in section. (3) The vaporizer according to claim 1 or 2, in which the fuel flowing out of the fuel jet is jetted into the intake passage from a lower level without passing through a higher level than the fuel oil level in the float chamber. vessel. (4) Claim 1 in which the shutoff valve prevents fuel from flowing out of the fuel jet even when fuel supply is not required.
The vaporizer according to any one of Items 1 to 3.