JPS60145450A - Pneumatic apparatus for temporarily concentrating gaseous mixture generated by caburator for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a carburetor for an internal combustion engine, and particularly to a device suitable for being assembled into a carburetor for transiently enriching an air-fuel mixture.

BACKGROUND OF THE INVENTION Several devices are known for enriching a mixture during certain phases of an engine process. In particular, there are devices that are adapted to operate in response to a decrease in the vacuum in the intake manifold and have a structure that allows them to perform their function even when the load on the engine increases.

Known devices of this type can be divided into two types. That is,
The first type is a device consisting of a concentrator valve that operates as long as the vacuum in the intake manifold is maintained below a certain predetermined value. In this way, the device supplies an associated conventional carburetor circuit (main or minimal) with a fuel flux whose range is determined by the strength of the suction force created by the air velocity within the carburetor. . A second type consists of a pneumatically controlled accelerator pump that operates transiently to supply a constant amount of fuel under pressure to the intake manifold.

[Problem sought to be solved by the invention] However, the above-mentioned known device does not solve the problem of mixture enrichment through a controlled transition using the metering device of the above-mentioned conventional circuit starting from the first moment of the transition. Not yet.

The main object of the invention is to solve the above problems with a reliable and inexpensive device that can be easily assembled into existing vaporizers.

[Means and operations for solving the problem] An apparatus suitable for transiently concentrating a mixture generated from a vaporizer, the apparatus including a housing housing first and second chambers separated by a diaphragm. Device. The first chamber communicates with the manifold via a vent tube and the second chamber communicates with the first chamber via metering holes across the plate. A force is exerted on the diaphragm due to the spring and the pressure acting on the side of the diaphragm. A third chamber, separated from the second chamber by a second diaphragm, communicates with the floating chamber via an inlet and with the main circuit via an outlet, and is constituted by a spring suitable for pressing the sphere on the seat. Closed by a valve. A cross bar integral with the diaphragm supports a push bar which unseats the sphere under the action of pressure on the diaphragm, opening the exit passage. Fuel is metered by bushes.

Example 1 The device shown in FIGS. 1 and 2 consists of a housing l suitable for assembly in a vaporizer, preferably mounted next to a floating chamber 2 in a horizontal plane.

The housing 1 has two opposing plates 4a at its center.
and a first diaphragm 3 fixed by 4b.
It includes. These two opposing plates divide the interior of the housing l into a first chamber and a second chamber. The first chamber 5 communicates with the intake manifold via a vent pipe 7, and the second chamber 6 - has a smaller diameter than said vent pipe 7 and has a metering hole 8 extending across the two opposing plates 4a and 4b. It communicates with the first chamber 5 via.

The first diaphragm 3 has a first diaphragm 3 facing the first chamber 5.
The second side surface 3b facing the side surface 3a and the second chamber 6
It includes.

The second chamber 6 includes a spring 9 with a front-rear axis, a play) 4
b, and the opposite end supported by the wall IO of the chamber 6, which elastically pushes the first diaphragm 3 away along a direction extending substantially parallel to the longitudinal axis of the spring 9. .

The second chamber 6 has a relatively large capacity, and even if a strong pressure difference occurs between the first chamber 5 and the second chamber 6 during the process cycle of the engine, It has a durable structure that can withstand changes in internal pressure. Such a mechanism allows the dimensions of the holes 8 to be kept at technically achievable values.

The second diaphragm 11 is fixed in its central part by two small plates 12a and 12b located opposite to the plates 4a and 4b of the diaphragm 3, and the second diaphragm 11 connects the second chamber 6 to the third chamber. Separated from the chamber 13, the third chamber 13 has a large entrance 1
It communicates with the vaporizer floating chamber 2 via 4 and with the vent pipe 15 via an outlet 16 . Mechanically, the vent pipe 15 also constitutes the main supply circuit of the carburetor, which includes fuel and air metering devices in a known manner. The outlet 16 is equipped with a metering bush 25 for metering fuel during operation of the device. The passage 16 is closed by a valve constituted by a seat 17 cooperating with a ball 18 and a spring 19. The sphere 18 closes the seat 17 by the thrust force of the spring 19.

The cross bar 20 is integrated with the plays 4a and 4b of the first diaphragm 3 and communicates with the small plays 12a and 12b of the second diaphragm 11.

The horizontal bar 20 includes a protrusion 21 that faces and interlocks with a protrusion 22 formed inside the wall 23 of the first chamber 5 under the elastic deflection action of the spring 9. There is. The end of the crossbar 20 opposite the protrusion 21 defines a push bar 24 which extends through the third chamber 13 and is capable of passing the outlet 18, applying pressure on the diaphragm 3 to 21 from facing the protrusion 22, the sphere 18 is moved from the seat 17.
Remove from.

In the position shown in FIG. 1, the end of push rod 24 approaches sphere 18 without contact. This arrangement makes it possible to effectively reduce the operating time of the device to a minimum.

The second diaphragm 11 forms a seal between the second chamber 6 and the third chamber 13 so that the fuel contained in the third chamber 13 is transferred to the second chamber 6.
prevent infiltration. The second diaphragm 11 allows the horizontal bar 20 to move in the axial direction without significant frictional resistance.

The surface area of the second diaphragm must be small enough to overcome the counterpressure against the movement of the crossbar 20.

The operation of the apparatus shown in FIGS. 1 and 2 will be explained as follows.

During the stable operating phase at low and lowest engine speeds, the vacuum in the intake manifold is not excessive. A corresponding vacuum pressure acts on both the first chamber 5 and the second chamber 6, and the first side surface 3d of the first diaphragm 3
and the forces brought about by the pressures applied to each of the second side surfaces 3b are balanced. Spring 9 maintains the device in the condition shown in FIG. In this state, the third chamber 13 does not communicate with the ventilation pipe 15 because the ball 18 closes the seat 17 under the elastic deflection action of the spring 19. The concentration of the mixture emerging from the carburetor is therefore determined by a conventional metering device in the main circuit 15.

If the vacuum in the intake manifold drops due to a sudden opening of the carburetor throttle valve, or if the load on the engine suddenly increases, the system will transiently enter the operating position shown in Figure 2. reach. In reality, the vacuum pressure in the first chamber 5 instantaneously reaches the vacuum pressure in the intake manifold. The first chamber 5 is connected to the manifold via a ventilation pipe 7. The vacuum pressure in said second chamber 6 is such that, at least initially, prior to the start of the transition period,
Maintained at normal vacuum pressure. The pressure difference across the sides 3a and 3b of the diaphragm 3 creates a force sufficient to overcome the elastic deflection action of the spring 9. In this way, the horizontal bar 20 moves along its longitudinal axis,
The push rod 24 is actuated to disengage the sphere 1B from the seat 17 against the action of the spring 18. As a result of the above, the third chamber 13 can communicate with the main circuit 15 via the outlet 16. The diaphragm 11 is also displaced by the lateral movement of the horizontal bar 20, thereby causing the third
The volume of the chamber 13 is reduced. As a result, the pumping effect is negligible due to the large cross-sectional area of the inlet 14 compared to the relatively small cross-sectional area of the metering bush 25, considering the small size of the second diaphragm 11. In this way, the fuel metered by the metering bush 25 is
No fuel is introduced into the main circuit 15 under pressure, or more precisely, when the vacuum pressure for fuel suction is particularly weak, the fuel is metered by a conventional metering device in the main circuit. Added instantly.

This makes it possible to achieve a precise enrichment of the mixture concentration, depending on the needs arising from the specific operating conditions of the engine.

As a result, the air crossing the holes 8 flows from the first chamber 5 to
A low vacuum prevailing in the second chamber 6 is entered. In this way, the difference in pressure applied to each of the first side surface 3a and the second side surface 3b of the first diaphragm 3 is gradually reduced.

In this way, the device sequentially returns to the structural arrangement as shown in FIG. As a result, the push rod 24 of the crossbar 20 is retracted along the direction of its anteroposterior axis, repositioning the sphere 1 on the seat 17 and supplying the fuel to the circuit 15 as required by the new operating conditions of the engine. Cut off the supply. Due to the particular shape of the device and the cross-sectional area of the bore 8, the duration for which the outlet 1B remains open depends on the initial difference between 1 and 1 of the vacuum pressures prevailing in the first chamber 5 and the second chamber 6. The above difference represents a change in the load on the engine.

The device shown in FIG. 3 relates to another embodiment of the invention and is different from the device shown in FIGS. 1 and 2 and described above, in that the hole 8 is replaced by the metering bush 8a. The only difference is that The metering button is connected to the ventilation pipe 7.
a, the second chamber 6 of the device according to the invention;
It is branched off from the vent pipe 7 in order to connect the manifold with the vent pipe 7. For the expert, it is clear that the solution proposed and shown in FIG. Some structural advantages can therefore be deduced, in particular in connection with a failure or blockage of the metering bush 8a, which is easier to repair.

In an additional embodiment of the invention, the metering hole 8 or metering bush 8a of the device of FIGS. 1 and 2 can be molded from a microporous synthetic material.

In another embodiment, the metering bushing 8a can be formed by an annular passage formed by inserting the rod 3 2 into the bushing. The bushing has a diameter larger than the diameter of the rod and has an appropriate length corresponding to this diameter. Said bar constitutes the end of a threaded element having a microthreaded portion inserted into a support hole with a corresponding microthread. The support hole is molded into a support framework suitable for keeping the bush centered. Other known sealing methods that do not allow non-employees to handle the threaded elements can also be implemented. The advantage of this solution is that the time for reversing the push rod 24 from the position of FIG. 2 to the position of FIG. 1 can be easily adjusted. This adjustment can be effected by a load loss proportional to the part of the bar inserted into the bushing during the installation of the carburetor or during the test phase via screw movement of the bar within the bushing.

Once the travel time requirements are determined, the seal method is applied.

In practicing the invention, any suitable dimensions, shapes or materials may be used to meet the requirements of a particular application. This use does not depart from the scope of the inventive concept as shown and described in this specification.

[Effects of the Invention] As is clear from the above description, according to the present invention, it is possible to achieve accurate enrichment of the mixture concentration according to the needs arising from the specific operating conditions of the engine.

[Brief explanation of drawings]

1 is a sectional view of the device according to the present invention, showing the first operating state; FIG. 2 is a sectional view of the device of FIG. 1, showing the second operating state; FIG. 3 is a sectional view of a device in a second embodiment of the invention. 1: housing, 2 - vaporizer floating chamber, 3: first diaphragm. 4a, 4b: Opposing plate, 5: First chamber, 6: Second chamber, 7: Ventilation pipe, 8: Measuring hole, 9: Spring, lO
: Wall, 11: Second diaphragm, +2a, 12b: Small plate, 13: Third chamber, 5 14: Inlet, 15: Ventilation pipe, 16: Yamaguchi, 17: Seat, 1
8: Sphere, 18: Spring, 20: Horizontal bar, 21: Projection, 22
: Projection, 23: Wall, 24: Push rod, 25: Measuring button Applicant: Unibar - Niss B.N. Representative Yutaka 1) Yoshio 6 Figure 1 Figure 6 Figure 2

Claims (6)

[Claims] (1) A device suitable for transiently concentrating a mixture generated from a carburetor of an internal combustion engine, the housing housing at least first and second chambers separated by an elastic diaphragm; a housing in which the diaphragm is fixed in its central part by two opposing plates; a vent pipe suitable for connection with the first chamber;
The above-mentioned vent pipe and/or the pressure in the intake manifold acts.
or a space defined by said first chamber, for deflecting said diaphragm towards a first position defined by a first limiting stop means and moving it to a second position defined by a second limiting stop means. a third chamber separated from said second chamber by an impermeable wall; said third chamber communicating with said floating chamber of said vaporizer; said third chamber being separated from said second chamber by an impermeable wall; a first passageway suitable for closing said third chamber, a second passageway comprising a fuel metering device, said third chamber being adapted to close off said second passageway; a second passageway suitable for communication with a circuit, an element associated with said plate suitable for acting on said valve to open said second passageway when said second position is occupied by a diaphragm, a second chamber; a second chamber characterized by a main body having a larger volumetric capacity than the first chamber, and a passageway mechanism of regulated dimensions is foreseen for connecting said space with the second chamber;
A device in which a chamber and said passageway mechanism establish in said second chamber the pressure value existing in said space with a desired delay. 2. The apparatus of claim 1, wherein said passageway mechanism includes an orifice that traverses said plate. 3. The apparatus of claim 1, wherein the passageway mechanism includes a metering orifice in the second vent tube directly connecting the second chamber with the intake manifold. (4) -■=The device according to claim 1, comprising a bushing made of a synthetic microporous material. (5) The passage mechanism includes a first bushing having an appropriate diameter and length, a push rod suitable for insertion into the bushing, and having a diameter slightly smaller than the diameter of the bushing, and a portion of the threaded element. The rod comprising the bushing 2 is supported by a structure suitable for maintaining the diameter axially on the bushing 2, and the mechanism and the structure are each provided with a thread and a screw seat, 1. Suitable for accommodating a push rod for axially moving a rod into said bushing, and also comprising a sealing mechanism to prevent undesired movement of the push rod. The device described. (6) Between the second chamber and the third chamber
2. The device of claim 1, wherein said partition comprises a resilient diaphragm.