JPH0429076Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention is an exhaust gas recirculation control valve, that is, an EGR
Regarding valve improvement, the present invention provides an EGR valve that operates well and can withstand long-term use.

[Prior art]

By increasing the amount of inert components in the mixture supplied to the internal combustion engine, the amount of gas per unit calorific value increases, which lowers the fuel temperature, thereby reducing the amount of NO generated in the exhaust gas. is known, and a method of lowering the combustion temperature by returning part of the exhaust gas to the intake air as an inert component and supplying it to the air-fuel mixture is widely practiced.

An exhaust recirculation control valve, that is, an EGR valve, is used in the circuit that performs exhaust recirculation.
A diaphragm valve is used as this EGR valve.

The diaphragm valve applies pressure to the diaphragm chamber formed in the upper part of the diaphragm via an EGR negative pressure adjustment valve that is activated by the pressure in the intake manifold, thereby discharging the diaphragm chamber and the outside air chamber of the adjacent chamber. is configured so that outside air acts on it.

Conventional EGR valves have a valve body fixed at one end,
It is necessary to ensure that the valve stem with a diaphragm fixed to the other end moves up and down smoothly, and to prevent EGR gas from leaking to the outside as much as possible. A button is provided.

Since the outside air chamber is located next to the valve part filled with EGR gas, it tends to be quite hot. Therefore, in order to cool the outside air chamber, a hole is made in the lower case constituting the outside air chamber to introduce outside air.

On the other hand, since the amount of EGR gas directly affects the performance of the internal combustion engine, care is taken to minimize the distance between the shaft and the bushing that supports the shaft.

By the way, as mentioned above, the conventional EGR valve is
It is necessary to minimize the distance between the valve stem and the hole provided in the bush through which the valve stem passes, and the structure in which the outside air chamber communicates with the outside air causes the following problems.

That is, while the vehicle is running, salt water, rainwater, muddy water, dust, etc. enter the outside air chamber through holes provided in the lower case that constitutes the outside air chamber, causing damage to the bushes and valve stems installed in the outside air chamber. This means that they will be invading the booth between them.

If left in this condition after the vehicle has been driven, rust will develop on the valve stem during that period, resulting in poor slippage between the valve stem and the bushing, and in some cases, the EGR valve will become stuck when restarted. Accidents such as malfunction or inoperability may occur.

Due to malfunction or inoperability of this EGR valve.
EGR operation became impossible, and the specified exhaust gas recirculation was no longer performed, resulting in worsening exhaust gas.

In order to solve the problems of the EGR valve, for example, Japanese Utility Model Application Publication No. 56-37773 has been proposed. The EGR valve described in this publication is
The seal part of the lower case that passes through the valve stem uses a double-layered sealing material (bushing) in which the atmospheric chamber side is made of carbon sealing material and the valve part side, that is, the outer wall side, is made of asbestos sealing material.

However, in the case of a sealing material having this structure, problems occur in the management of parts, and resistance increases, resulting in worsening of movement of the valve stem. Additionally, salt water, rainwater, muddy water, dust, etc. may enter the gap between the valve stem and the sealing material, causing rust on the valve stem and causing the same drawbacks as described above.

In order to prevent foreign substances such as salt water from entering the outside air chamber, it is necessary to make the cover that makes up the outside air chamber a sealed type. It cannot be adopted.

On the other hand, in cold regions, salt is sprayed to prevent road surfaces from freezing, but as a result, it is unavoidable that foreign substances such as salt water enter the outside air chamber of the EGR valve as described above.

[Purpose of invention]

This invention prevents the valve stem from becoming stuck to the bushing, which is a sealing member, even if foreign matter such as salt water enters the outside air chamber of the EGR valve, and furthermore, the space between the bushing and the valve stem is as a proper value
EGR that prevents EGR gas from leaking to the outside air chamber side
It provides a valve.

Furthermore, the present invention provides an EGR valve configured such that the bushings exhibit excellent sealing function without substantially changing the structure of the conventional EGR valve.

[Summary of the idea]

To achieve the above object, the present invention has an oil supply hole connected to a valve stem hole of a bushing fixed to an outside air chamber that supports a valve stem having a diaphragm fixed to one end and a valve body fixed to the other end. The cylinder head cover and the oil supply hole are connected by a hose via a check valve.

That is, the present invention is configured to supply oil to the bushing that forms a seal between the outside air chamber of the EGR valve and the valve chamber in which the valve body is housed, and supports the valve shaft while the internal combustion engine is stopped. This is what I did.

For this purpose, an oil supply hole is opened in the bushing to intersect with the hole passing through the valve stem. It is not necessary to constantly supply oil to this oil supply hole, and it is sufficient to supply oil after the internal combustion engine is activated. As a method to improve the oil retention effect, forming an oil retention groove such as an annular groove near the oil supply hole,
A porous bearing alloy is used for all or part of the bushing.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-section of an internal combustion engine and an EGR valve. The EGR valve 1 is composed of a diaphragm part 2 and a valve part 3. The diaphragm part 2 has a diaphragm between an upper case 4 and a lower case 5. A diaphragm chamber 7 and an outside air chamber 8 are formed with a diaphragm chamber 7 and an outside air chamber 8 interposed therebetween.

A valve shaft 9 is fixed to the center of the diaphragm 6, and a valve body 10 is provided at the other end of the valve shaft 9, and is configured to open and close a valve seat 12 provided inside the main body 11. There is.

A protrusion 5a is formed in the center of the lower case 5, and a bush 13 is fitted into the protrusion 5a. The bush 13 is provided with an oil supply hole that intersects and communicates with the hole through which the valve shaft 9 passes, and a pipe 14 is press-fitted into this oil supply hole, and one end of a hose 15 is connected to this pipe 14. Note that the lower case 5 is provided with an opening 22 to allow outside air to enter and exit.

On the other hand, the cylinder head cover 1 of the internal combustion engine 16
A pipe 18 is fixed through the side of 7, and is connected to the hose 15 via a hose 19 and a check valve 20.

An opening 11a at the bottom of the main body 11 is an EGR gas supply port, and an opening 11b at the side of the main body 11 is a communication port with an inlet manifold of the internal combustion engine 16. Further, a pipe 21 provided in the diaphragm chamber 7 communicates with a negative pressure regulating valve operated by the negative pressure of the intake manifold.

Next, the operation of the device according to the present invention will be explained.

During operation of the internal combustion engine 16, the pressure inside the cylinder head cover 17 becomes positive and the pressure inside the inlet manifold (not shown) becomes negative, so the inlet manifold is connected to the inlet manifold at the opening 11b. The inside of the valve chamber 11c becomes a negative pressure, and accordingly, the space between the valve shaft 9 and the bush 13 also becomes a negative pressure. Therefore, since negative pressure acts on the check valve 20 via the hose 15, the valve body 20a moves to the position indicated by the dotted line and closes one end of the hose 19.
Although this hose 19 opens inside the cylinder head cover 17, the oil mist floating inside the cylinder head cover 17 does not flow toward the bush 13 because the check valve 20 is closed.

When the internal combustion engine 16 stops, the inside of the cylinder head cover 17 and the inside of the inlet manifold are both at atmospheric pressure, so the valve body 2 of the check valve 20
0a is pushed up and opened by the force of the spring 20b. Then, the oil mist accumulated in the hose 19 between the cylinder head cover 17 and the check valve 20 and the oil droplets condensed from the oil mist pass through the check valve 20 and pass through the hose 15 and pipe 14. It is fed into the bush 13.

The oil droplets are supplied between the valve stem 9 and the bush 13 to lubricate the valve stem 9 and the bush 13 and prevent the valve stem 13 from rusting.

FIG. 2 shows a cross section of a bush 13 having another structure, in which a hole 14a into which a pipe 14 is press-fitted is provided perpendicular to a hole 9a through which the valve shaft 9 passes;
An annular groove 14 is formed along the upper and lower inner peripheral surfaces of this hole 14a.
b is formed.

FIG. 3 shows a cross section of a bush 13 of still another structure.
4a is provided.

By using the bush 13 as shown in FIGS. 2 and 3, it is possible to ensure the amount of oil retained while fully exhibiting the sealing function.

[Effect of idea]

This invention provides a oil supply hole that connects to the valve shaft guide hole of the bushing, which is provided in the part of the diaphragm part of the EGR valve where the valve shaft passes through between the outside air chamber and the valve chamber. Since it is connected to the head cover via a check valve that is closed while the internal combustion engine is operating, the following effects can be achieved.

When the internal combustion engine stops, oil mist and oil droplets that have accumulated in the hose or pipe between the cylinder head cover and the check valve are supplied to the oil supply hole in the bushing. lubrication is improved.

Therefore, even if salt water or dust that enters the outside air chamber of the diaphragm of the EGR valve adheres to the valve stem during operation of the internal combustion engine, the bushing is always lubricated with oil, so the valve stem that passes through the bushing will be protected. There will be no rust on the parts.

When the internal combustion engine is started again,
The EGR valve does not stick and operates smoothly, keeping the internal combustion engine in good operating condition.

As described above, since the valve stem is not stuck to the bushing while the internal combustion engine is stopped, the distance between the valve stem hole provided in the bushing and the valve stem can be in an optimal state.

Further, even if foreign matter such as salt water enters the outside air chamber of the diaphragm portion, problems such as sticking of the valve stem will not occur, so the outside air chamber can be opened to fully exhibit its heat dissipation effect.

Moreover, the present invention can be implemented with conventional EGR valves without substantial modification.

[Brief explanation of drawings]

Figure 1 shows an internal combustion engine according to an embodiment of the present invention.
2 and 3 are sectional views showing the shape of the bush. 1... EGR valve, 2... diaphragm section,
3...Valve section, 4...Upper case, 5...Lower case, 6...Diaphragm, 7...Diaphragm chamber, 8...Outside air chamber, 9...Valve stem, 13...Button, 16...Internal combustion Engine, 17...Cylinder head cover, 20...Check valve.

Claims (1)

[Scope of utility model registration request] A diaphragm is attached to one end and a valve body is fixed to the other end. In order to support the valve stem, an oil supply hole is provided by connecting to the valve stem hole of a bushing fixed to the outside air chamber, and the oil supply hole is connected to the cylinder head cover and the oil supply hole is provided. An exhaust recirculation control valve that is connected to a hole with a hose via a check valve.