JPH018774Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a negative pressure control valve that continuously and variably controls negative pressure using electric current. The control valve of the present invention continuously controls any negative pressure servo system, and its application is not particularly limited, but it is effective for use, for example, in controlling the negative pressure of an EGR valve in a diesel engine.

In other words, unlike gasoline engines, diesel engine EGR control does not have a negative pressure source that changes depending on the load, so a negative pressure control valve that can vary the amount of negative pressure depending on the load is required. Therefore, there is a need for a control valve that continuously controls negative pressure as in the present invention.

In the negative pressure control valve of the present invention, a valve holding member having a magnetic part is supported by a diaphragm, and an electromagnetic attractive force is applied to the valve holding member to apply an attractive force to the diaphragm, thereby reducing the negative pressure in the diaphragm chamber. The basic configuration is to change the size of.

That is, an object of the present invention is to electrically control the negative pressure in the diaphragm chamber by changing the negative pressure in the diaphragm chamber depending on the magnitude of the electromagnetic attraction force.

The present invention will be explained below based on an embodiment shown in the drawings.

In Figure 1, 1 is a diesel engine, 2
is its fuel injection nozzle. 3 is an EGR passage that connects the exhaust system 4 and intake system 5 of the engine; 6 is an exhaust gas control valve that opens and closes this EGR passage 3;
Control quantity. 31 is a load sensor that detects the load on the engine, and 32 is a computer. Reference numeral 10 denotes a negative pressure control valve, which is disposed in the middle of a signal passage 9 that communicates between the vacuum pump 8 and the diaphragm chamber 7 of the exhaust gas control valve 6.

Next, this negative pressure control valve 10 will be explained with reference to FIG. The negative pressure control valve 10 includes a cover 11,
The outer wall is composed of the housing 12 and the yoke 13,
The outer periphery of a rubber diaphragm 14 is held between the cover 11 and the housing 12. Further, the cover 11 is provided with a negative pressure intake port 16 and a negative pressure outlet port 17 that communicate with the diaphragm chamber 15 . The inner periphery of the diaphragm 14 is held between valve holding members 21 made of a magnetic material such as iron. The valve holding member 21 has a passage 24 therein which communicates the diaphragm chamber 15 and the atmosphere opening chamber 18, and this passage 24 is opened and closed by the valve body 22 coming into contact with and separating from the valve seat 25. It is becoming more and more common.

The valve body 22 has an electromagnetic attraction force acting on the valve holding member 21 (that is, acting on the diaphragm 14),
Drive according to the balanced relationship between the spring force applied by the compression coil spring 23 to the valve body 22 and the force applied to the diaphragm 14 due to the pressure difference between the diaphragm chamber 15 and the atmospheric release chamber 18 that maintains atmospheric pressure as a reference pressure. be done.

First, when the output negative pressure (the pressure inside the diaphragm chamber 15) determined by the computer 32 based on the signal from the load sensor 31 is relatively high,
In this case, a large current is passed through the coil 28,
Pull the valve holding member 21 downward as shown.
Thereby, the valve body 22 comes into contact with the valve seat 25 formed on the inner surface of the valve holding member 21 under the pressure of the coil spring 23, and the communication between the diaphragm chamber 15 and the atmosphere opening chamber 18 is cut off. At the same time, the valve body 22 opens a valve seat 26 formed at the tip of the negative pressure intake pipe 11a of the cover 11, allowing negative pressure to be introduced from the negative pressure intake port 16 into the diaphragm chamber 15.

When negative pressure is introduced into the diaphragm chamber 15 in this way, the negative pressure inside the diaphragm chamber 15 increases, and a receiving pressure that pulls the diaphragm 14 (valve holding member 21) upward in the figure is generated, and the coil The suction force exerted by 28 and the pressure received by the diaphragm 14 are balanced, and the valve holding member 21 is held in a state in which the valve body 22 closes both the valve seat 26 on the negative pressure intake side and the valve seat 25 on the atmospheric pressure intake side. Ru.
On the other hand, if the output negative pressure calculated by the computer 32 becomes smaller, the amount of current applied to the coil 28 is reduced.
When the current applied to the coil 28 decreases, the attraction force decreases, so the diaphragm 1 that had been maintained until then decreases.
The balance between the receiving pressure applied to 4 and the suction force is disrupted,
The valve holding member 21 is pulled upward by the pressure applied to the diaphragm 14 . In this case, the valve body 22 is the valve seat 2 at the tip of the negative pressure intake pipe 11a.
6 and does not move any further, the valve holding member 2
Only 1 will move upward.

As a result, the valve body 22 comes into contact with the valve seat 26 to prevent negative pressure from being introduced into the diaphragm chamber 15 from the negative pressure intake port 16, and also separates from the valve seat 25 and connects the diaphragm chamber 15 and the atmosphere port 20. is communicated through the air port 24 provided in the valve holding member 21 and the filter 19, thereby reducing the negative pressure in the diaphragm chamber 15.

In this case, as the negative pressure inside the diaphragm chamber 15 decreases, the diaphragm 14 (valve holding member 2
1) is reduced, the suction force of the coil 28 and the receiving pressure of the diaphragm 14 are balanced in a new force relationship, and the valve element 22 is connected to the valve seat 26 on the negative pressure intake side and the atmospheric pressure intake. The valve holding member 21 returns to the position where it closes the side valve seat 25 together.

As described above, by operating the valve body 22, the negative pressure in the diaphragm chamber 15 is reduced to the load sensor 3.
A predetermined equilibrium underpressure value required on the basis of the signal 1 is maintained, so that the exhaust gas control valve 6 performs an optimum exhaust gas recirculation.

That is, the load sensor 31 and the computer 32 increase the amount of current applied to the coil 28 as the engine load decreases, so when the load is low, a relatively large negative pressure in the diaphragm chamber 15 is applied to the diaphragm chamber 7 of the exhaust gas control valve 6. A large amount of exhaust gas is refluxed. Conversely, when the load increases, the amount of current applied to the coil 28 decreases, the output negative pressure decreases, and the exhaust gas control valve 6 reduces the amount of recirculated exhaust gas.

Note that when the coil 28 is energized, the valve holding member 2
1 through the gap 29 between the valve holding member 21 and the stator core 27, there is a correlation between this attraction force and the gap 29. In other words, the attraction force characteristics are as shown in FIG. When the gap 29 is wide as in the position B, the increase in attraction force per unit current becomes small. Therefore, the relationship between current and output negative pressure is as shown in Figure 3, and the diaphragm chamber 1
When the gap 29 is narrow, the negative pressure at No. 5 changes to A with a large slope. Therefore, by adjusting the gap 29, the change in the negative pressure in the diaphragm chamber 15 relative to the current value, in other words, the output negative pressure can be adjusted to a desired value. Therefore, in this example, housing 1
A gap adjustment shim (not shown) is interposed between 2 and the yoke 13.

In addition, 30 in FIG. 1 is a buffer material for preventing adsorption between the valve holding member 21 and the stator core 27 and made of an elastic non-magnetic material such as rubber.

In the above example, the output negative pressure corresponding to the load is stored in the computer 32 in advance, and the load sensor 3
The amount of current applied to the coil 28 was determined uniquely according to the signal from the computer 3.
The actual output negative pressure may be fed back to No. 2. That is, the load sensor 31 is connected to the computer 32.
In addition to the signal from the load sensor 31, the pressure inside the diaphragm chamber 15 is also input as a signal, and when the actual pressure inside the diaphragm chamber 15 is smaller than the value calculated based on the signal from the load sensor 31, the The amount of current applied to the coil 28 is increased according to the difference.

As explained above, in the control valve of the present invention, the valve holding member has a magnetic part, and a passage connecting the diaphragm chamber and the constant pressure chamber is provided inside the valve holding member.
The valve body has both the function of holding the valve body that opens and closes the passage and the function of a moving core that receives electromagnetic attraction force, so that the valve body can open and close both the negative pressure intake port and the atmospheric air introduction passage. This has the excellent effect that the output negative pressure can be electrically controlled with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing an embodiment of the control valve of the present invention, and FIGS. 2 and 3 are explanatory views showing the relationship between the gap, suction force, and output negative pressure. 10... Negative pressure control valve, 11... Cover, 12...
...Housing, 14...Diaphragm, 15...
Diaphragm chamber, 16... Negative pressure intake port, 1
7... Negative pressure extraction port, 18... Atmospheric release chamber (reference pressure chamber), 21... Valve holding member, 22... Valve body, 24... Passage, 28... Coil.

Claims (1)

[Scope of utility model registration request] a cover having a negative pressure intake port and a negative pressure output port and forming a diaphragm chamber together with the diaphragm; a housing disposed on the opposite side of the cover with the diaphragm in between and forming a reference pressure chamber together with the diaphragm; and the diaphragm. a valve holding member supported by a magnetic member and having a passage connecting the diaphragm chamber and the reference pressure chamber and having a magnetic member; A negative pressure control valve comprising: a valve body that opens and closes; and an electromagnetic coil for applying an excitation attraction force to the diaphragm via the valve holding member.