JPS5970864A - Variable venturi type carburettor - Google Patents

Abstract

PURPOSE:To satisfy an air-fuel ratio required by an engine and to save fuel consumption, by supplying fuel directly from a fuel passage to an intake-air passage downstream of a venturi section, in accordance with engine operating conditions. CONSTITUTION:A communication passage 49 communicated to an intake-air passage 32 downstream of a vanturi section 36 and formed through an intake-air pipe 31 and a nozzle guide 40, is communicated to a hole 39 through a port 50. Further, a nozzle body 44 is formed with a vertically extending elongated oil hole 51 in the position which is opposed to the port 50 when a lever 45 is pulled down. By adjusting the degree of pull-down of the lever 45, the opening area of a port 50 may be adjusted with respect to a fuel passage 47. That is, the communication area of the communication passage 49 may be controlled by a control means 52, and therefore, the amount of fuel sucked up from the communication passage 49 may be controlled. Accordingly, the air-fuel ratio may be properly set in accordance with engine temperatures and atmospheric temperatures, thereby the enhancement of exhaust characteristics and the save of fuel consumption may be made.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to a variable-type, saturated carburetor, and in particular to a Sl+ vaporizer.

(2) Prior Art A conventional variable venturi carburetor is known, for example, as described in Takashi Yoshida's ``Theory and Practice of Carburetors'' (published by Railway Japan Co., Ltd.), as shown in Figure 1.2. It is shown as follows. The variable venturi carburetor is disposed upstream of the throttle valve 2 in the intake passage 1, and includes a venturi fixed part 3 and a venturi movable part 4 that forms a venturi part 4 between the fixed part 3 and the venturi fixed part 3. It has a part 5.

The vent fixing part 3 has a protrusion 6 extending in a strip shape at right angles to the intake passage l, and a nozzle guide 7 is inserted into a hole formed in the center of the protrusion 6. There is. An idle adjustment nut 8 is screwed onto the tip of the nozzle guide °7, and a sprig 10 is fitted between the eye I' adjustment nut 8 and the intake pipe 9.Nozzle guy 1- A nozzle body 12 having a nozzle 11 formed at one end thereof is housed within the nozzle body 7 so as to be movable, and a connector 14 having a lever 13 attached thereto is screwed to the other end of the nozzle body 12. The lever 13 is used to automatically or manually push down the nozzle body 12 downward in the diagram when starting the engine, and the I connector 14 is urged upward in the space time diagram by a spring (not shown). A 1-meter fuel passage 15 is formed in the nozzle body 12, and fuel is supplied from the float chamber 17 through the two-liter connector 14 and the fuel pipe I6.
7 is supplied with fuel from an evening feed link (not shown) via a knee valve 8, and according to the amount of fuel supplied to the float chamber 17, the ζ float 19 floats and closes the needle valve 18. Therefore, the float chamber 17
The amount of fuel in the nozzle body 12 is kept constant, and fuel is supplied to the nozzle body 12 from the float chamber 17 up to a predetermined level.

On the other hand, the venturi movable part 5 is disposed at a position facing the fixed part 3, and is connected to the traction cylinder 20.
It has a suction screw 23 that is slidably housed in the crayon cylinder 20 and partitions the inside of the suction cylinder 20 into an atmospheric chamber 21 and a negative pressure chamber 22, and is fixed to the F end surface of the suction piston 23. A hench pulley portion 4 is formed between the portion 3 and the hench pulley portion 4. Atmospheric pressure is supplied to the atmospheric chamber 21 through the atmospheric pressure passage 24, and the negative pressure chamber 22
The venturi Y4-1 on the downstream side of the venturi portion 4F is introduced through the crayon hole 25 formed in the tension piston I/N 23. The cranking ring 23 is compressed within the negative pressure chamber 22 and biased toward the fixed portion 3 by a tension spring 26.

Therefore, the liquid reaction screw 23 moves due to the force difference between the popular chamber 21 and the negative pressure chamber 22, the force of the suction spring 26, and the balance between the weight of the suction piston 23 and the fixed part 3. They approach each other and are separated by Al1. A tapered jet needle 27 is attached to the tip of this screw type piston 23.
This jet needle 27 is the nozzle 1! It penetrates inside. Therefore, the nozzle body 120 and the nozzle 11 have an annular 4-shaped ring between them and the jet needle 21.
A p-section is formed, the passage area of which increases as the rotation piston 23 moves away from the fixed section 3. Note that 28 is an oil damper that suppresses the vibration of the compression piston 23 and prevents the vibration of the compression piston 23 due to the pulsation of intake air.

In this variable venturi carburetor, due to the venturi negative pressure generated in the venturi portion 4 in response to the intake air p, the narashijin piston 23 is aligned with the fixed portion 3 and approaches or separates from it. l'l to move
', the passage area of the measuring section changes. Therefore, the amount of fuel corresponding to the amount of intake air is sucked out from the fuel passage 15 to the intake passage 1 through the 41M section, and the air-fuel ratio of the air-fuel mixture is kept constant.

Also, when cranking, move the lever 13 to: 11.
Fuel is increased each time you press down on the lower blade in the diagram. Meanwhile, when the lever 13 is pushed down, the nozzle body 12 is pulled down along the nozzle guides 1-7, and the passage surface of the n1 room is moved. From 15 to δ1, the amount of fuel sucked into the intake passage 1 increases through the weight 7, and the engine starts 1.
．． ing. stop.

When the engine has completely started, the nozzle body 12 moves in both directions as shown in Figure 1, and reaches the position where the I-neck 14 comes into contact with the idle adjuster I. Stop.

The passage area of the n1 section determined by the position of the nozzle 11 at each time determines the air-fuel ratio at idle. Therefore, the air/fuel ratio at idle can be adjusted by rotating the eye wheel adjuster 8 and adjusting its position #.

However, in the conventional variable bench 1 carburetor like this one, the tapered shape of -1 l is used to properly maintain the required air-fuel ratio in each operating state after the intercalary warm-up.・) When JFJ is set up, -me, when starting the west gate, special ε
(The air temperature will reach the freezing point.) No. 4 At the time of starting at a low temperature of In other words, at low temperatures, the cranking speed is slow and the amount of intake air is small, so the negative pressure on the bench cannot be increased sufficiently, and the viscosity of the fuel is high. , iH1 from the fuel passage
The amount of fuel sucked out into the intake passage through the
It is not possible to obtain a dense empty/flood ratio (indicated by the area Δ in FIG. 3) sufficient for cranking in the curve (indicated by the curve ■ in FIG. 3). As a result, there were problems in that it took a long time to start the engine, and the engine stalled immediately after starting. Also, if the position of the nozzle body is set to satisfy the air-fuel IL during cranking,
As shown by the curve ■ in Figure 3, the sky j during eye ring is
The μ ratio is the required air-fuel ratio after complete explosion (shown in the middle area HB in Figure 3).
There was a problem that it became darker and the engine stalled.

(3) Purpose of the Invention Accordingly, the present invention provides the air-fuel ratio required by the engine by supplying fuel directly from the fuel 11 passage to the intake passage on the downstream side of the intake passage. The purpose is to achieve satisfaction.

(4) Structure of the Invention The variable venturi fixing part 1 of the present invention includes a fixing part installed on the upstream side of the throttle valve in the intake passage, a nozzle arranged in the fixing part to supply fuel to the intake passage, and a fuel outlet in the nozzle. A Venturi part is formed between the fuel passage supplying the fuel and the fixed part, and the negative pressure of the venturi part causes the venturi to move closer to the fixed part by a distance of 1 Pill.The area of the venturi increases. 3.9-cushion piston with variable tip and nozzle
1ti is inserted in the jet needle to change the nozzle opening area according to the movement of the suction piston, are communicated through a communication passage, and C control is performed based on the operating state of the engine using the jmm area control means of the communication passage.
Fuel is supplied from the communication passage depending on the operating state of the engine.

(5) Examples The present invention will be described in detail below with reference to the drawings.

FIG. 4 is a diagram showing a first embodiment of the present invention, and 31 is an intake pipe in which an intake air amount WPr32 is formed.

Intake '>m A throttle valve 33 interlocked with an accurel pedal is provided in the W832, and a variable venturi carburetor 34 is provided upstream of the throttle valve 33. The variable venturi carburetor 34 includes a venturi fixed part 35 and a venturi movable part 37 that forms a venturi part 36 between the fixed part 35 and the venturi fixed part 35 .

The venturi fixing part 35 is perpendicular to the intake passage 32 and has a diameter of 41
It has a protrusion 38 extending in a single shape, and a nozzle guide 40 is provided in the center of the protrusion 38 where a hole 39 is formed. An eye 1-4 adjuster 4I is fitted on the outer periphery of the tip of the nozzle guide 40, and a spring 42 is compressed between the eye 1-41 and the intake pipe 31. There is. This spring 4:3 biases the eye adjuster 41 to prevent it from loosening. A nozzle body 44 having a nozzle 43 formed at one end is slidably housed in the hole 39 of the nozzle guy 1'40, and a lever 45 is installed at the other end of the nozzle body 44. The connector 46 is mated. Lever 454; When starting with J$1+1 concave, the nozzle body 4 is automatically moved in and out with the connector 6.
4 is pressed by force F in Fig. 4 -F'', which is then biased against the upper blade by a spring (not shown).No.
47 is formed, and the furnace fuel is supplied to a predetermined level from a float chamber (not shown) through a connector 46 and a fuel pipe 48.
1 and the nozzle guide 40: <Nturi part 3
61': A communication path 49 is formed that communicates with the intake air amount 1i'i'i 32 on the downstream side, and this communication W849 communicates with the hole 39 through the bow 151). In addition, Nosurupoti 4-i has Po 15 when lowering L/par 45.
An oil hole 51 is formed at a position facing J-0 and extends in the upper F direction in the figure, and as shown in FIG. As the nozzle body 44 moves up and down, the i\ of the boat 50 is larger than the maximum length of the oil hole 51 in the direction of the structural force. Therefore, as the nozzle body 44 moves up and down, the The opening area for the fuel passage 47 changes, and the oil holes 51 formed in the bows 1 and 50 and the nozzle body 44 constitute a control means 52.

Referring again to FIG. 4, the movable part 37 has a compression piston 53 slidably housed in a cylinder (not shown), and the lower end surface of the piston 53 and the fixing part 35 form a joint part 3G therebetween.

The interior of the Zakujon Bis 1 53 is divided into a popular chamber into which atmospheric pressure is introduced, and a negative pressure chamber 55 into which negative pressure is introduced through the leakage ball 54, and further, It is contracted in the negative pressure chamber 55 and is biased in the direction of the fixed HP 35 force by an action spring 56. Therefore, the tension screw 1 53 moves relative to the fixed part 35 due to the pressure difference between the atmospheric chamber and the negative pressure chamber 55, the biasing force of the tension spring 56, and the balance between the weight of the tension screw 1 53. Approach/separate from each other. At the tip of this crayon piston 53, there is a jet knee (57) for use at the beginning, and this jet knee (57) passes through the inside of the nozzle 43. Therefore, the nozzle body 4
4 ()) / Sufu1z43f! An annular 41-door section is formed between the li-min. It increases as time goes by.

Next, the action will be explained.

The FiJ variable temperature venturi carburetor 34 is (of the gate), during lightning operation, the Zakujon screw 1 53 is pressed against the fixing part 35 due to the venturi negative pressure generated in the venturi part 3 [i].
Approaching with illusion/1i1tlv! It moves and sucks out the fuel corresponding to the intake flow rate from #1 weight and keeps the empty ratio constant. However, the negative pressure downstream of the negative pressure chamber 55 is introduced into the negative pressure chamber 55, and when the intake flow rate increases, this negative pressure is received and r-! L action pis 1 53
moves. Movement of this Jixigonbis1n53 ε:1
The venturi negative pressure continues until the negative pressure reaches a predetermined negative pressure (determined by the E1 force of the Crayon spring 5G, the weight of the Zakujo piston 53, etc.), and the venturi negative pressure applies this predetermined negative pressure to the lightning. It becomes pressure. As the jiction piston 53 moves, the jet needle 5
'/ also moves, and the passage surface and bonds of the gt M section change. Therefore, the amount of fuel sucked into the intake passage 32 from the fuel tank changes according to the intake flow rate, and the air-fuel ratio is kept constant.

At the time of starting operation, a rich air-fuel mixture is required, and in this case, the air-fuel ratio is enriched by pulling down the lever 45. That is, when the lever 45 is pulled automatically or by a sliding motion when starting the engine, the oil hole 51 formed in the nozzle body 44 moves to a position facing the boat 50, and the oil hole 51 formed in the nozzle body 44 moves to the downstream side of the venturi portion 36 of the intake passage 32. and the fuel passage 47 communicate with each other, and the fuel in the fuel passage 47 is sucked out into the intake passage 32 through the control means 52 and the communication passage 49 due to the intake pipe negative pressure. Furthermore, by pulling down the lever 45, the passage area of the IM section increases, and the amount of fuel sucked out from the metering section into the intake passage 32 increases. In order to suck out the phosphorus from both the communication passages 49 and 81 in this way, the shape of the engine nodney L 57 is adjusted so that the air-fuel ratio is kept constant depending on the various operating conditions after the engine is started. Even when set to 1), it is possible to satisfy the rich air-fuel ratio (area Δ) required at cranking, as shown by curve 1 in Figure 3, and improve engine startability. I can do it. In addition, the shape of the oil hole 51 is longer in the direction of the lower blade in the figure, and the lateral length is shorter in the direction of F. By J', the combustion t'1 passage 47 of Bow 1-5 (]
It is possible to adjust the area of the open L-mass that corresponds to 1. That is, the first control stage 52 can control the passage area of the communication passage A9, and can control the amount of fuel sucked out from the communication passage A9. Therefore, the air-fuel ratio can be set appropriately according to the engine temperature and the air temperature, which improves the engine performance and fuel efficiency. Save V)
be able to.

Fig. 6.7 shows a second embodiment of the present invention, and in explaining this embodiment, only the same reference numerals are used for the same components as in the first embodiment, and the explanation thereof will be omitted. do.

The variable venturi carburetor 58 of this embodiment has a communication passage 49 that communicates between the fuel passage 60 of the fixed part 59 and the intake passage 32.
The circuit area is controlled at two locations. In other words, 6
(3) is a control valve installed in the communication passage 49, and the control valve 61
The valve body 62 opens and closes the communicating passage 49 using the intake pipe negative pressure. The valve body 624;J-111:1 part is inserted into the communication path 49, and the other end is
The diaphragm 63 is fixed to the intake pipe 31 and divides the inside of the gauging 64 into an atmospheric chamber 65 and a negative and positive chamber 66.

Intake pipe negative pressure is introduced into the negative pressure chamber 66 through the h pressure pipe 67 and U7, and the diaphragm 63 is moved toward the atmospheric chamber 65 side (=J
Forced. Therefore, the diaphragm 63 moves in relation to the pressure difference between the atmospheric chamber (5) and the negative pressure chamber 66 and the force of the spring 68,
3 moves, the valve body 62 moves to open and close the communication passage 49. The operating intake pipe negative pressure of the control valve 61 is set, for example, as shown in FIG. In addition, nozzle body 6
As shown in FIG. 7, the oil hole 70 formed in the nozzle body 69 is located at the uppermost position (the position where the connector 4G contacts the A1 lug and toss L nut 41).
) Even when the bow 1-50 is closed to the fuel passage 60 [''
The horizontal length of the oil hole 70 becomes shorter toward F in the figure. The oil hole 70 and the ball 15 (l constitutes a control means 71) formed in the above-mentioned 11, control, /1''6I and nozzle body 6I.

This 111 variable vent tip and carburetor 58 can be adjusted by pulling the lever 45 when starting the engine.
The open 11 area of the fμ feed communication path 60\ of 50 increases by 1σ, and the area of the jIN path of the old M portion increases. When starting the engine, the negative pressure in the intake pipe is low.
Since the control valve 61 is small at about 1g, the control valve 61 is connected to the communication path 49.
open. Therefore, the fuel in the fuel passage 1i'86 (1) is sucked out from the enlarged n1 volume part by the negative pressure, and passes through the boat 50 and the communication passage 49, which are wide open by the intake pipe negative pressure, to the intake passage 32. This makes it possible to satisfy the rich air-fuel ratio required in the case of the first embodiment and during intermittent cranking.

When the engine is idling, the intake pipe fl: becomes 0!100mm11g, and the control valve 61 closes the four connected paths. Therefore, C, fuel passage 60
The fuel 1 is sucked out only from the metering part, and the air-fuel ratio at the time of air-ring can be satisfied.

The transition of the air-fuel ratio from the cranking force (1 and 2) to the eye 1 ring occurs because the control valve 61 closes at 7 in response to the development of intake pipe negative pressure, as shown in curve IV in Figure 3. The transition is smooth and the engine performance after cranking is improved.

Further, when the negative pressure in the intake pipe does not develop significantly, such as during high load and low rotation, but a rich mixture is required, the control valve 61 opens at tJ and the nozzle body 61 is positioned at the uppermost end. Even in cases where the communication passage 49 is the fuel passage 6 ()
Because it has a small opening, JrA can pass through the communication path 49.
fl is supplied. As a result, a +'yl rich air-fuel ratio is obtained, and the operating performance of the engine is improved.

In addition, in each of the examples described in "-", if stream air is introduced into the communication path 49 to atomize the combustion particles 1, the -RtJ
l! Leap driving performance improves -1:, J'.

(L3) Effect According to the present invention, even if the air-fuel ratio is set to 7, the air-fuel ratio is kept constant under various operating conditions after the engine starts. air fuel ratio J
I; Can be supplied to IJ, improving engine startability to 1i
iJ-1 can be improved and the operating performance of the engine can be improved.

Furthermore, in the second embodiment, even in an operating state where the intake pipe negative pressure does not develop but requires a rich mixture, fuel can be supplied from the communication passage, and the engine can be operated. Performance can be further improved.

[Brief explanation of the drawing]

Part 1.21 M&J is a diagram showing a conventional variable carburetor, and FIG. 1 is a front view thereof, and FIG.
The figure is a side view, and Figure 3 is a diagram comparing the relationship between intake pipe negative pressure and air-fuel ratio between the variable venturi carburetor of the present invention and a conventional variable venturi carburetor. ￥S4.5 Figure is a diagram showing the first embodiment of the variable venturi carburetor of the present invention,
FIG. 4 is a front view of the same, FIG. 5 is an enlarged sectional view showing its control means, FIGS. 6 to 8 are views showing a second embodiment of the variable venturi carburetor of the present invention, and FIG. 7 is an enlarged sectional view showing the positional relationship between the boat and the oil hole, and FIG. 8 is a diagram showing the operating intake pipe negative pressure of the control valve. 32---Intake passage, 33---One throttle valve, 34,! T, 8, --- variable venturi carburetor, 35.
60------Venturi fixing part, , 36---
--- Bench lily part, 43 --- Nostle, 47.60 -- Fuel passage, 49 -- Series 1ffl passage, 52.71 --- Control means, 53 --- No. 1 John piston, 57 -----J-Ets Tony 1°. Patent Applicant Nissan Motor Co., Ltd. Patent Attorney Ugagun Part Figure 1 Figure 2 Figure 5 Figure 7 Figure 8 Figure 6 Figure 8

Claims (1)

[Claims] A fixed part provided on the upstream side of the throttle valve in the intake passage, a nozzle arranged in the fixed part that supplies fuel to the intake passage, a fuel passage that supplies fuel Y.1 to the nozzle, and the fixed part. A venturi part is formed between the piston and the suction piston, whose tip is loosely inserted into the nozzle. In a variable venturi carburetor equipped with a jet needle whose nozzle opens in response to the movement of the fuel passageway and a jet needle whose area changes according to the movement of the fuel passageway, the downstream side of the venturi portion of the intake passageway is connected to the fuel passageway. 1. A variable venturi carburetor, characterized in that the variable venturi carburetor is provided with a control means for controlling the passage area of the communication passage.