JPS6111495Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a negative pressure extraction device for an exhaust gas recirculation device.

FIG. 1 shows an example of a conventional exhaust gas recirculation device.

In FIG. 1, there is a throttle valve 2 in a throttle valve chamber 1 constituting a part of an intake passage 3.
The intake air amount of the engine 4 changes depending on the opening degree of the engine 4.
An exhaust gas recirculation path 7 is in bypass communication between the exhaust path 6 and the intake path 3 of the engine 4, and an exhaust gas recirculation valve (hereinafter referred to as an EGR valve) 10 is installed in the middle of the path.
By adjusting the amount of exhaust gas recirculated by the engine, combustion conditions in the engine are controlled, and the amount of NOx contained in the exhaust gas is reduced.

The EGR valve 10 changes the cross-sectional area of the exhaust gas recirculation path 7 by moving a needle 12 facing the opening of the exhaust gas recirculation path 7 up and down in proportion to the negative pressure generated near the throttle valve 2 . That is, an exhaust gas recirculation amount proportional to the amount of intake air in the intake passage 3 is obtained. EGR
To briefly explain the structure of the valve 10, the needle 12
is fixed to the center of the diaphragm 13,
This diaphragm 13 is pulled up when the negative pressure working chamber 15 in its upper part becomes negative pressure and moves to a place where the force of the compression spring 14 is balanced, so that the needle 12
moves in the direction of opening the exhaust gas recirculation path. As shown in FIG. 1, the negative pressure working chamber 15 is communicated with an opening provided in the intake passage 3 near the throttle valve 2 through a negative pressure pipe (hereinafter referred to as EGR pipe) 5. Two branch pipes are connected to a control valve 20.

The control valve 20 has a flat diaphragm 27 and a bellows-shaped diaphragm 23, whose central portions are closely fixed to each other to form a negative pressure chamber 21 and a negative pressure chamber 22. The negative pressure chamber 21 communicates with a pipe branched from the inlet side of the negative pressure working chamber 15 of the EGR valve 10 of the EGR pipe 5, and the negative pressure chamber 22 communicates with the intake path 3 downstream of the throttle valve 2 and the negative pressure pipe 8. It has been made to communicate with each other.
A sealing member 26 made of a rubber plate is attached to the upper central surface of the diaphragm 27, and a pipe having an air opening 25 closely facing the sealing member 26 branches off from the EGR pipe 5. In addition, outside air flows through a porous filter 28 into the chamber into which the atmosphere opening 25 is inserted, and the pressure is at atmospheric pressure. A compression spring 24 is installed in the negative pressure chamber 22. Further, 11 is an orifice.

In the conventional exhaust gas recirculation system configured as described above, when the engine 4 rotates and the throttle valve 2 opens and intake air flows into the engine, the air opens near the throttle valve 2.
The inside of the EGR pipe 5 becomes negative pressure and the negative pressure chamber 2 of the control valve 20
1 and the pressure in the negative pressure working chamber 15 decreases, and the needle 12 is pulled up to increase the amount of exhaust gas recirculation. However, immediately after that, the seal member 2 along with the diaphragm 27
6 is pulled down, so it is away from the atmosphere opening 25,
Air is introduced from this to reduce the negative pressure in the negative pressure chamber 21 and the negative pressure working chamber 15. Therefore, the sealing member 26 approaches the atmosphere opening port 25 by the spring force of the compression spring 24 and suppresses the introduction of air, so that the negative pressure in the negative pressure chamber 21 and the negative pressure working chamber 15 increases again. Since the negative pressure in the intake passage 3 downstream of the throttle valve 2 is transmitted to the negative pressure chamber 22 of the control valve 20 by the negative pressure pipe 8, the negative pressure chamber 22 becomes a negative pressure for the time being.
Generally, this negative pressure is smaller than the negative pressure near the throttle valve 2, so the pressure in the negative pressure chamber 22 is higher than the pressure in the negative pressure chamber 21. Therefore, the relatively high pressure of the negative pressure chamber 22 and the force of the compression spring 24 act to reduce the distance between the sealing member 26 and the atmosphere opening 25, and the atmosphere opening 25 and the seal are sealed at an appropriate position. As a result, the gap between the members 26 is balanced, and the opening degree of the needle 12 is also determined. Additionally, if the opening degree of the throttle valve 2 changes, the intake air amount also changes, and the position of the needle 12 of the EGR valve 10 changes in the same way, so the recirculated exhaust amount can be obtained in proportion to the intake air amount. Become.

In FIG. 1, the negative pressure signal source for operating the EGR valve 10 is taken out from the vicinity of the throttle valve 2 in the throttle valve chamber 1. There is only one negative pressure outlet opening, but in some cases there may be two openings in the vertical direction close to the throttle valve 2.
There may also be separate locations. However, in any case, this negative pressure is directly guided to the EGR pipe to operate the EGR valve 10. Therefore, when the throttle valve 2 of the intake passage 3 is opened rapidly, the amount of recirculated exhaust gas increases rapidly, which has a negative effect on the operating condition. In other words, when a vehicle starts or accelerates rapidly, a surging phenomenon in which the engine vibrates minutely or a breathing phenomenon in the exhaust gas occurs, which deteriorates driving performance, causes discomfort to the driver, and increases the amount of substances in the exhaust that are a source of pollution. I was letting it happen.

The present invention aims to provide an exhaust gas recirculation device that can operate smoothly even during rapid acceleration, and includes an exhaust gas recirculation path that communicates an intake path and an exhaust path of an engine, and a midway point of the exhaust gas recirculation path. a diaphragm connected to the valve body and driving the valve body; a negative pressure working chamber formed by the diaphragm; and a negative pressure working chamber formed near the throttle valve of the intake passage. In an exhaust gas recirculation device comprising a negative pressure pipe for guiding pressure, a first small chamber connected to the negative pressure pipe and a combination orifice comprising the first small chamber and a pore are provided on the wall of the intake passage near the throttle valve. forming a second small chamber that communicates with the intake passage near the throttle valve through a second orifice;
The first chamber is connected to the second chamber through a first orifice.
It is characterized in that it communicates with the intake passage on the upstream side of the orifice.

FIG. 2 is a sectional view of a throttle valve chamber according to an embodiment of the present invention, and the same members as in FIG. 1 are designated by the same reference numerals. A second orifice 32 is provided on the wall of the intake passage 3 near the throttle valve 2, and a first orifice 31 is located relatively far from the throttle valve 2.
are provided close to each other in the vertical direction. A first small chamber 35 connected to the first orifice 31 and a second small chamber 36 connected to the second orifice 32 are partitioned by a partition wall, and these small chambers 3 are separated by a combination orifice 33 provided on the partition wall.
5 and 36 are in communication. First orifice 31
The EGR pipe 5 is connected to the first small chamber 35 which is opened. Note that the blind plug 34 is connected to the two small chambers 35 and 36 and the combination orifice 3.
It was embedded to close the upper and lower ends after processing No. 3.

In the throttle valve chamber 1 having such a structure, when the throttle valve 2 rapidly rotates in the direction of the arrow to increase the intake air amount,
First, a relatively weak negative pressure is generated in the first orifice 31, and a strong negative pressure is generated in the second orifice 32. However, since the negative pressure in the second orifice 32 passes through the combination orifice 33, transmission of the strong negative pressure signal is delayed, and the negative pressure in the EGR pipe 5 rises in a relatively gentle curve. When the throttle valve 2 gradually opens, the negative pressure in the throttle valve section is guided to the EGR pipe 5 without any time delay.

Figure 3 is a diagram comparing the increase in negative pressure in the EGR pipe due to the throttle valve chamber in Figure 2 during rapid acceleration and slow acceleration.The vertical axis indicates the negative pressure in the EGR pipe in -mmHg. ,
The horizontal axis indicates the opening degree of the throttle valve in degrees. solid line 40
The rise in the negative pressure in the throttle valve chamber during sudden acceleration, as shown by 41, is gradual, and in the case of slow acceleration, as shown by broken line 41, the negative pressure rises in proportion to the opening degree of the throttle valve. Omit the first orifice 31 and use the second orifice 32 directly.
The conventional type connected to the EGR pipe 5 draws a curve like the broken line 41 regardless of the speed or speed of acceleration.

Therefore, the EGR recirculation rate shows a gradual rise as shown by the solid line 40 in Figure 3 during sudden acceleration, which provides good engine drivability and suppresses the generation of pollutants in the exhaust gas. It has the advantage of being able to

Fig. 4 is a diagram comparing the characteristics of the embodiment shown in Fig. 2 and the conventional device during sudden acceleration. %)
The lower half shows the negative pressure of the EGR tube in -mmHg. Solid lines 42 and 43 are curves showing the state during sudden acceleration according to this embodiment, and dashed-dotted lines 44 and 45 are EGR curves.
This is a curve showing the state of a conventional device in which a pipe is communicated with one orifice during sudden acceleration. As can be seen from the figure, in the conventional device, the negative pressure at the throttle valve directly
Since the signal was transmitted through the EGR pipe to open the EGR valve, the amount of recirculated exhaust gas increased rapidly, degrading the engine's operating performance.

Figure 5 is a diagram comparing other characteristics during sudden acceleration between the embodiment shown in Figure 2 and the conventional device, where the vertical axis is
The EGR reflux rate is shown in %, and the horizontal axis shows time in seconds. As shown by the solid line 46, the EGR recirculation rate % during sudden acceleration according to this embodiment has a slower rise than the dashed-dotted line 47 indicating the EGR recirculation rate during sudden acceleration according to the conventional device, resulting in a delay of 0.9 to 1.2 seconds. .

As described above, this example demonstrates the effect of gradually increasing the amount of exhaust gas recirculation during rapid acceleration through a relatively simple structural improvement in which two orifices are provided and a pore communicates between them. This is also obtained from the results.

The throttle valve chamber of the embodiment shown in FIG. 2 is provided with two orifices. For example, the second orifice 32
It is also possible to provide one additional orifice close to the top of the. In this case, there is an advantage that the shape of the EGR reflux rate curve can be adjusted more finely.

The negative pressure extraction device of the exhaust gas recirculation device of the present invention has the effect of allowing smooth operation even during rapid acceleration, and has great industrial effects.

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining an example of a conventional exhaust gas recirculation device, Fig. 2 is a sectional view of a throttle valve chamber that is an embodiment of the present invention, and Fig. 3 is an EGR using the throttle valve chamber of Fig. 2.
Figures 4 and 5 are diagrams showing a comparison of the rise in negative pressure in the tube during rapid acceleration and slow acceleration. Compare the characteristics of the embodiment shown in Figure 2 and the conventional device during rapid acceleration. This is a line diagram. 1... Throttle valve chamber, 2... Throttle valve, 3... Intake path, 4... Engine, 5... Negative pressure pipe (EGR pipe),
6... Exhaust path, 7... Exhaust recirculation path, 10... Exhaust recirculation valve (EGR valve), 20... Control valve, 31... First orifice, 32... Second orifice, 33...
...Combination orifice chair.

Claims (1)

[Scope of utility model registration request] an exhaust gas recirculation path that communicates an intake path and an exhaust path of the engine; a valve body provided in the middle of the exhaust gas recirculation path;
A diaphragm that is connected to the valve body and drives the valve body, a negative pressure working chamber formed by the diaphragm, and a negative pressure pipe that guides the negative pressure generated near the throttle valve in the intake passage to the negative pressure working chamber. In the exhaust gas recirculation device, a first small chamber is connected to the negative pressure pipe on a wall of the intake passage near the throttle valve, and a second small chamber is communicated with the first small chamber via a combination orifice formed of a pore. The second small chamber communicates with the intake passage near the throttle valve via a second orifice, and the first small chamber communicates with the intake passage upstream of the second orifice via the first orifice. A negative pressure extraction device for an exhaust gas recirculation device, characterized in that the device is in communication with the exhaust gas recirculation device.