JPS5918112Y2 - Dash pot for throttle valve closing speed control - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dashpot used for controlling the closing speed of a throttle valve.

In automobiles, etc., when the throttle valve is suddenly closed when driving at high speed, the intake negative pressure downstream of the throttle valve increases.
A large amount of fuel is sucked into the intake passage from an idle port that opens into the intake passage downstream of the throttle valve, and at the same time, the amount of air sucked into the intake passage rapidly decreases.

Therefore, if you close the throttle valve suddenly like this,
The fuel could not be completely combusted in the cylinder, and the amount of unburned hydrocarbons in the exhaust gas increased, which was bad in terms of exhaust gas control.

On the other hand, if the throttle valve is closed at a slow speed, the amount of unburned hydrocarbons in the exhaust gas decreases, which is preferable in terms of exhaust gas countermeasures, but the engine brake becomes ineffective, which poses a problem in terms of driving and safety.

In order to reconcile these two conflicting matters, by closing the throttle valve rapidly in the initial stage of its closing operation, it is possible to satisfy drivability and safety, and also to improve the closing operation of the throttle valve. It is considered desirable to slowly close this throttle valve in the latter stage to suppress the increase in unburned hydrocarbons in the exhaust gas.

An object of the present invention is to provide a dashpot that satisfies the aforementioned throttle valve closing performance by controlling the closing speed of the throttle valve in stages.

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is the main body of the carburetor, 2 is the intake passage in the main body 1, and 3 is the throttle valve (3) that opens and closes the intake passage 2.
Throttle valve), 4 is a shaft that rotatably supports the throttle valve 3 on the main body 1, and the left end of the intake passage 2 in the figure is connected to an intake pipe (not shown) of the engine.

When the throttle valve 3 is rotated clockwise, its opening degree increases.

5 is an arm fixed to the shaft 4 at a right angle; 6 is a screw screwed at right angles to the tip of the arm 5; the tip of the screw 6 faces in the direction in which the throttle valve 3 is closed;

One end of a lever 7 is rotatably supported on the shaft 4 adjacent to the arm 5, and a rod 8 is rotatably connected to the other end of the lever 7.

A screw 6 is located in the middle part of the lever 7 within the rotation locus of the tip of the screw 6 and is inserted in the latter stage of the closing operation of the throttle valve 3.
A stopper 9 is fixed, with which the tip of the stopper 9 comes into contact.

10 is a flow control valve.

This flow control valve 10 has a one-way valve 13 and an orifice 14 arranged side by side on a partition wall 12 that divides the inside of a case 11 into two chambers A and B.

Therefore, in this flow rate control valve 10, when fluid flows from chamber A to chamber B, the fluid flows through one-way valve 13 and orifice 14, and when fluid flows in the opposite direction, fluid flows through orifice 14. Flows only through.

A chamber A of this flow control valve 10 is connected downstream of the throttle valve 3 of the intake passage 2 via a passage 15, and a chamber B is connected to the downstream side of the throttle valve 3 of the intake passage 2 through a passage 15.
It is connected by a passage 17 to a sealed chamber C inside.

This sealed chamber C is formed between one side of the diaphragm 18 and the case 16.

Note that the diaphragm 18 divides the case 16 into two chambers C and D.

The diaphragm 18 as a pressure receiving member includes a flange 8a at the inner end of the case 16 of the rod 8 passing through the case 16;
It is composed of a flexible sealing membrane 19 held between the flange 8a and the case 16, and the diaphragm 18 faces the sealed chamber C so as to be movable forward and backward.

A spring receiver 20 is arranged in the sealed chamber C in parallel with the flange 8a.

This spring receiver 20 is supported within the case 16 by a flexible membrane 21.

22 is a large diameter communication hole bored in the spring receiver.

A first compression spring 2 is provided between the flange 8a and the spring receiver 20.
3 is interposed, and a second compression spring 24 whose spring force is sufficiently smaller than that of the compression spring 23 is interposed between the spring receiver 20 and the inner wall of the sealed chamber C.

In this way, the compression springs 23 and 24 are interposed in series between the diaphragm 18 and the inner wall of the sealed chamber C.

Reference numeral 25 designates a stopper screwed onto the case 16 so that it can move forward and backward toward the spring receiver 20.

Next, the operation of the dashpot having such a configuration will be explained.

When the accelerator (not shown) is suddenly released from a large depression state, the throttle valve 3 rotates counterclockwise from a large opening and closes.

Assuming that the point in time when the accelerator is released is to in FIG. 2, at the initial point in time, the throttle valve 3 is abruptly closed at the same time as the accelerator is released.

This operation is performed until the screw 6 rotates together with the throttle valve 3 via the shaft 4 and the arm 5 until the tip thereof hits the stopper 9 of the lever 7.

Next, when the tip of the screw 6 hits the stopper 9, the counterclockwise rotation of the throttle valve 3 is restrained by the spring force of the compression springs 23 and 24.

At this time, since the opening degree of the throttle valve 3 is also sufficiently small, the intake negative pressure downstream thereof is large.

This intake negative pressure gradually acts on the diaphragm 18 of the sealed chamber C through the orifice 14 of the flow control valve 10 and the passages 15 and 17, and the diaphragm 18 moves in the direction of compressing the compression springs 23 and 24 in the sealed chamber C. Displace.

As a result, the compression spring 24 is gradually compressed until the spring receiver 20 hits the screw 25 as a stopper, and then the compression spring 23 is gradually compressed.

Due to the action of the compression springs 23 and 24, the displacement speed of the diaphragm 18 is changed in two stages.

This displacement of the diaphragm 18 is transmitted to the stopper 9 via the rod 8 and the lever 7, and the stopper 9 rotates in a direction to close the throttle valve 3.

Therefore, if the time from when the compression spring 24 is compressed to when the spring receiver 20 comes into contact with the screw 25 is tl, the closing speed of the throttle valve 3 will be slightly slower from 10 to tl as shown in FIG. 23 begins to be compressed, the closing speed of the throttle valve 3 becomes even slower, and the throttle valve 3 becomes fully closed at time t2.

In the embodiment described above, an example was shown in which two compression springs 23 and 24 with different spring forces were interposed in series between the diaphragm 18 and the inner wall of the sealed chamber C, but the invention is not necessarily limited to this. Instead, three compression springs 2 with different spring forces are used.
3.24.26 may be interposed in series between the diaphragm 18 and the inner wall of the sealed chamber C as shown in FIG. It may be inserted in between.

In FIG. 3, 27 is a spring support supported by the case 16 by a flexible membrane 28, 29 is a communication hole drilled in the spring support 27, and 30 is provided protruding from the surface of the spring support 27 facing the spring support 20. It is a stopper.

As explained above, in the present invention, the pressure receiving member connected to the lever for adjusting the throttle valve opening is movably faced into the sealed chamber to which the intake pipe negative pressure is introduced, and the pressure receiving member is connected to the inner wall of the sealed chamber. In between, at least a first spring is placed on the pressure-receiving member side, a second spring having a spring force smaller than the first spring force is placed on the inner wall side of the sealed chamber, and a spring having a communicating hole is provided. Since the deformation is restrained through the bridge and two or more springs are interposed in series, the throttle valve (7) is suddenly closed at the initial stage of the closing operation. In addition, in the latter stage of the closing operation of the thrower I/L valve, the spring with a small spring force on the inner wall of the sealed chamber first reduces the negative pressure in the intake pipe. Furthermore, due to the communication hole in the spring holder, the spring with a large spring force on the pressure receiving member side receives negative pressure from the intake pipe and slowly contracts, and due to these actions,
Since the thrower I/L valve is closed, an increase in unburned hydrocarbons in the exhaust gas can be reliably suppressed.

[Brief explanation of drawings]

Fig. 1 is a piping system diagram of a carburetor and dashpot showing one embodiment of the present invention, Fig. 2 is a closing speed characteristic curve diagram of a throttle valve, and Fig. 3 is a dashpot showing another embodiment of the present invention. FIG.

Claims (1)

[Scope of utility model registration request] A pressure-receiving member connected to a lever for adjusting the throttle valve opening is movably faced into a sealed chamber into which intake pipe negative pressure is introduced, and a pressure-receiving member is provided between the inner wall of the sealed chamber and the pressure-receiving member at least on the pressure-receiving member side. a first spring, and a first spring on the inner wall side of the sealed chamber.
A second spring having a spring force smaller than that of the spring is provided through a spring receiver having a communication hole so that deformation is sequentially restrained as the spring deforms, and two or more springs are connected in series. A dashpot for controlling the closing speed of a throttle valve, characterized in that it is equipped with a.