JPS5820954A - Variable venturi type carburetor - Google Patents

Abstract

PURPOSE:To make an additional fuel supplying mechanism unnecessary and uniform the atomization of the fuel and the mixture thereof by a method wherein the annular Venturi is formed between an axially reciprocating movable body and a throat section opening the orifice thereof at the inner peripheral surface of a housing. CONSTITUTION:The movable body 3, reciprocable into up-and-down directions along the axial direction of an air path and movable in accordance with the movement of an accelerating pedal, is arranged in the air path coaxially therewith while the throat section 2, protruded inwardly with a reduced diameter so as to form the annular Venturi between the upper outer surface of said movable body 3, is provided at the inner surface of a housing 1. The annular orifice 4, communicating with a supply path 23, is opened at the throat section 2 along the whole periphery of the minimum inner-diametral section and the fuel is supplied through a float chamber and the supply path 23 by a vacuum generated by an airflow being flowed through the Venturi formed by the throat section 2 and the movable body 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a carburetor for supplying mixed air with a required mixture ratio of 11 to an internal combustion engine 111, in particular a downflow variable venturi valve for use in an automobile MS Sekikawa. venturi 111
It's about bulk.

#1Al11$1 for automobiles has a variable load condition, so even if you use a carburetor for that purpose, it is difficult to feed the internal combustion engine with an appropriate mixture ratio depending on the load condition and rotational speed of the internal combustion engine. However, the very big problem 5 here is the response of the carburetor when changing from no load or light load to full load, such as when starting or suddenly accelerating. In other words, a general vaporizer has a fixed bench 1
Whether it is a single type or a variable venturi type, fuel is supplied according to the flow velocity of intake air flowing through the internal air passage, but under the above conditions, it is not possible to supply the required lean mixture. It will disappear. It takes 67t to accelerate suddenly now.
When you step on the accelerator, the throttle valve opens and the degree of negative pressure in the two intake mantles decreases due to the vent, and although the amount of air flowing through the carburetor increases, its flow rate decreases. This is because the internal combustion engine is slow, or not fast, and cannot obtain the necessary air pressure during sudden acceleration, causing the internal combustion engine to suddenly start up suddenly or stop. For this purpose, in the past, an additional mechanism such as a power jet that operates to supply fuel was generally provided during sudden acceleration, but this made the structure of the Vi carburetor more complicated.
Adjustment will take a lot of time and effort.

The present invention has been made in view of the above points, and its purpose is to create a mixture with the same mixing ratio required by the venturi not only at no load, but also at full load. We can supply fuel so that
No additional fuel supply mechanism is required, and since the venturi is annular and the fuel supply orifice is located around the entire circumference of the annular venturi, the fuel can be atomized and the mixture of fuel and air can be uniform. An object of the present invention is to provide a variable bench single-type carburetor in which conversion is performed extremely well.

The present invention will be described below based on illustrated embodiments. (1) in the diagram
is a housing with an air passage that has a circular cross section passing through the center vertically, and this housing (1
) is formed with a supply channel communicating with a float chamber adsorbed on the outer surface of the float chamber. A movable body (3) is disposed within the air passage and is coaxial with the air passage and can reciprocate up and down along the axial direction, and an upper outer surface of the movable body (3) is disposed inwardly of the housing (1). A companion seat portion (2) is provided which projects inward and has a smaller diameter so as to form an annular bench reel between the two. Soot part (2
), an annular orifice (4) communicating with the supply path (2) opens over the entire circumference in the small inner diameter portion, and a venturi between the stream s(2) and the movable body (3). Under the negative pressure generated by the airflow flowing through the float chamber, fuel is sucked out from the annular orifice (4) through the supply channel (2) and into the air channel.

The movable body (3) responds to the accelerator and moves downward in response to the depression of the accelerator to increase the volume of the venturi.
to save. Then, the air bleed mechanism sends air into the fuel passage according to the degree of negative pressure of the internal combustion engine. It is formed into upper and lower halves by the upper housing (b), and an f clear housing (not shown) is connected to the upper part of the upper housing (b). The two intake man leads of the inner m-ring gate are connected to the lower part of υ. The throat part (2) is integrally provided with the upper suction part and material O absorbed in the lower part of the inner surface of the upper housing, and integrally protrudes inward on the upper part of the lower housing part. The annular orifice (4) is formed as a gap between the upper throat member 04 and the lower throat member. ′
The inner diameter of the upper housing S (b) is approximately constant along the axial direction, but the main stator member Qj4 is formed with an inclination rjji such that the inner diameter decreases as it goes downward. The phantom inward direction is a convex curve in which the inner diameter gradually increases from the upper end, which is also the tip of the lower throw 1 member.
] (C) Continuing from this convex curved end, the inner diameter gradually increases, and then the inner diameter gradually becomes smaller, passing through a concave curve, and then connecting to the lower surface. There is.

There is a hole in the lower part of the illusion, upwards and downwards,
A plurality of supply passages are provided with their upper ends opening at the upper surface, and each supply passage communicates with a foot Y member housed outwardly in the lower housing sill and a communication hole. Each supply channel A has 7 liter air pipes H installed at equal intervals in the lower part of the upper housing (B), with their lower ends having micro holes arranged below the liquid gap at the end of the supply channel. It's embedded. Each supply lol! The upper end of A communicates with the annular orifice (4) through a through hole (11) bored in the upper housing (2).
The other end communicates with the air pipe 94 to form an air bleed mm.

The movable body (3) Fi disposed in the housing (1) configured as described above is attached by press-fitting into one opening of the lower housing eυ and slides in the axial direction by a table plate. It is provided on a freely supported throttle shaft (5), and the lower main body part (6), which is marked by the throttle shaft (51), and the throttle shaft (51) slide roughly up and down in the axial direction of the throttle shaft (51). The main body part (6) is movably arranged and consists of an upper valve body (7). The end of the chamber in which the return spring cI of the movable body (3) is housed is in sliding contact with the throttle shaft (5) and is sealed except for communication with the upper part of the air passage through nine ventilation holes. Note that this vent hole is closed when the chamber end becomes negative pressure and the main body part (6
) to prevent it from interfering with its upward return. - indicates a nut for mounting the main body (6) onto the throttle shaft (5;).

The main body part (6) further has a small diameter part in the upper part, and the lower part of the valve body (7) is slidably fitted into this small diameter part. This valve body (7) is screwed into the upper outer part of the throttle shaft (5) and a spring (9) which is disposed between the main body 5 (6) and urges the valve body (7) upward. The springs disposed between the flange portion Q@ at the upper end of the cylindrical g-force and elastically biasing the valve body (7) downward are in contact with each other at the top and bottom, respectively. The valve body (7) that comes into sliding contact with the outer surface of the cylinder (lη) has a slightly weaker spring force than the spring (9), so
Normally, it is placed at a position 111ifl above the main body (6). An O-ringy is formed between the valve body (7) and the main body (6), and is housed in the main body (6) and contacts the inner circumferential surface of the lower part of the valve body (7). A sealing member provided and in contact with the outer circumferential direction of the cylindrical body Qη,
17), the member pressure chamber (8) is formed in the main body (6) and is connected to the air passage below the throw 1 part (2) through an L communication hole Wt. The bolt is a lock bolt that prevents the threaded connection of the cylinder body O to the throttle shaft (5) from loosening.

Next, the operation will be explained. Figure 1 shows the state when the internal combustion engine is not running, and no negative pressure is generated in the intake mandrel, and the valve body (7) is simply a pair of springs. (9) - Negative pressure is generated in the main body (6) - mouth part until i1 is balanced through the communication hole in the negative pressure chamber (8).
The negative pressure chamber (8) acts as a vacuum piston and pushes the valve body (7) slightly downward against the splash (9).
31 move. In this state 1i11, the first factor is shown by an imaginary line.

The outer periphery 11 of the upper end portion, which is the largest diameter of the valve body (7), faces the inner side of the stem portion (2) to minimize the area of the annular venturi. Therefore, the flow rate of the air flowing through this bench is fast, and the amount of fuel sucked out from the orifice (4) is larger than the amount of air passing through the pliers. This makes it possible to supply the fuel and air mixture necessary to start the internal combustion engine.

When the internal combustion @ threshold is operated under a light load such as when idling or driving on a flat road at a constant speed, the slot shaft (5) and the main body (6) are
) moves downward, and at this time, the degree of negative pressure in the intake manifold is high (approximately -250WJIHg -s
00ssmHg), the degree of negative pressure in the negative pressure chamber (81 is also high, and the lower edge of the valve body (7) moves downward until it touches the main body g (61) and moves to the next position, and the valve body moves according to the opening degree of act tlL+. (7) contacts the main body part (6) and moves up and down in a straight line. This is the state shown in Figures 2 and 3. The actuator (7) is depressed by K50 depending on the amount of accelerator depression, and the actuator is depressed to bend the venturi. However, when the internal combustion engine's rotation speed is not increased or the rotation speed is not increased, the throttle shaft (5) and the main body 5 (6) move downward according to the input of the engine. At this time, as mentioned above, the degree of negative pressure in the intake mantle is reduced (-100w).
aHg~-2Q Q saHg) and the suction force of the valve body (7) against the negative pressure chamber (8) decreases, so the valve body (7) 7) moves upward with respect to the main body (6), and as shown in FIG. 4, the vertical area of the bench becomes smaller. Therefore, although the degree of negative pressure in the intake manifold is low,
The flow rate of the air flowing through the Lee is fast, and since the amount of fuel roughly corresponding to this flow rate is supplied from the orifice (4), the required mixed air can be supplied. When the rotational speed of the internal combustion engine is high up to the IP1 rotation speed, the degree of negative pressure increases again, so the force moves downward against the valve body (6) against the spring (9), and the body Department (
6) to vII#. 1* - When the accelerator pedal is returned to the down position shown in Figure 4, when the accelerator pedal is released, such as when stopping acceleration midway or when transitioning from pitching to flat ground driving, the main body part (6) moves upward and the main body part (6) moves upward. In order to prevent the passage of the flowing air between the part (6) and the lower throat member from becoming narrower and increasing the flow velocity, the main body part (6) is communicated with the lower throat member at a minimum distance from each other. Since the hole (E) is open, the degree of negative pressure of bond pressure * ta+ is increased. Therefore, the main body '81Sl
The valve body (1) does not move upward with the upward movement of lIl, and the valve body (1) moves downward relative to the main body (6), resulting in the state shown in FIG. 2.

The operating pressure (degree of negative pressure) for the valve body (1) in the negative pressure chamber (8) is determined by the threading of the cylinder aη onto the throttle shaft (6).
By changing the spring force of the spring (11) instead of k', it can be set to an appropriate value.It is particularly difficult to manufacture the spring (9) with a constant spring constant, but this manufacturing error can be corrected by changing the spring constant of the spring (9). The position of the valve body (71) relative to the main body (6) can be set as planned by adjusting the compression ratio of (to).

In the illustrated embodiment, one end of the negative pressure chamber (a communication hole for connecting the negative pressure chamber 81 and the lower air passage) is opened at the upper side surface of the main body (6); ) may be opened on the lower side or lower surface of the main body.

(6) An appropriate shape is taken into consideration (Moadeshi,
For example, the upper housing lj(
The inner shape of the river is also similar.

As described above, in the present invention, an annular variable bench 1 is formed between a movable body that reciprocates in the axial direction and a throat portion having an orifice opened on the inner peripheral surface of the tube. Since fuel is supplied to the annular air flow flowing through this annular venturi from orifices around the entire circumference, fuel atomization and air-fuel mixture homogenization are performed extremely well. The movable body consists of an upper valve body that forms an annular venturi in the darkness with the throw 1 part, and a lower main body that responds to the accelerator pedal. A negative pressure chamber is provided that is connected to the air below, and the valve body is elastically biased upward relative to the main body, so that the valve body moves up and down according to the degree of negative pressure in the main body and the lower air passage. Depending on the load situation in the internal combustion engine, the valve body moves up and down with respect to the main body due to the suction force in the negative pressure chamber, and the rich air-fuel mixture is
Despite the fact that the internal combustion engine's rotational speed does not change to F6 depending on the opening of the accelerator, the pressure of the intake manifold decreases and the speed of the air flow in the venturi decreases. The valve body moves upward as the negative pressure increases, reducing the venturi area and increasing the flow velocity of the air flowing through the venturi to increase the ruts of fuel sucked out from the orifice. It supplies a mixture with a crowded ratio to the internal combustion engine without the need for an additional fuel supply mechanism such as a power jet.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 shows a cross section when the internal combustion engine is stopped, Fig. 2 shows a cross section when there is no load, Fig. 3 shows a cross section when a light load is applied, and Fig. 4 shows a cross section when a heavy load is applied. It is a diagram. ! l) is the housing, 1 is the throat part, ! S) Beam cutting body, (4) is orifice, (i) is throttle shaft, (6) is main body, (7
) indicates a valve body, (8) indicates a negative pressure chamber, (9) (to) indicates a spring, and - indicates a communication hole. Agent Patent Attorney Ishi 1) Chief 7'1S 1 Figure 2 Figure 3 Figure 8 Figure 4

Claims (3)

[Claims] (1) A cylindrical air passage penetrating vertically, a part a-) protruding into this air passage, and an inner II4 edge Kfii of the throat part
A housing having an annular orifice with a Q opening and a part 11 disposed coaxially with the part 20 in the air passage and reciprocatingly in the vertical axial direction are inserted into the housing for downward movement. and a movable body for a throttle forming an annular variable bench lary in which the venturi pile becomes large. The throat part is elastically biased upward against the main body part, and the upper cone-shaped valve body is connected only to the lower air passage and forms a negative pressure 11, The valve body forming the variable valve body between the throat part and the main body part is configured to move up and down according to the degree of negative pressure in the lower air passage which is applied to the intake manifold. Variable venturi mgL converter with features. (2) Between the upper end of the shaft extending upward from the main body and the upward direction of the valve body, apply a biasing force that is weaker than the force that urges the valve body upward against the main body. The i3T variant pentel described in the first aircraft in the scope of Patent No. 111 is characterized in that a spring body is interposed to elastically bias the body downward, and the downward biasing force of the I11 by this spring body is formed as kqR. One vaporizer/ (3) A patent lll characterized in that the communication hole FiqlIb is provided in the main body part of the body, and one end thereof is opened toward the upper part of the main body part, which communicates with the negative pressure chamber and the air passage below the throat part. Range of demands! ! IIIJJ description: 0 town change pliers 1 one time vaporizer.