KR20010064296A - Egr valve - Google Patents

Abstract

PURPOSE: An EGR(Exhaust Gas Recirculation) valve is provided to prevent a diaphragm having low intensity against heat from aging by interrupting heat transfer thereto and to improve durability by inhibiting carbon from flowing back. CONSTITUTION: A diaphragm(11) is moved to a vacuum chamber(13) by compressing a return spring(16) as a strong negative pressure is applied to the vacuum chamber. A valve(4) is separated from a valve seat(3) and interlocking with the lifting of an upper and a lower disk member(12,10). Thereby, a return line is opened and exhaust gas is supplied to an intake system. The hot exhaust gas heats the valve, a working rod(5), a housing(2), and particularly, a ceramic filter(mesh filter,20) by flowing through the housing. Herein, an insulating material(19) is mounted between the ceramic filter and a bush(18) to isolate heat transfer to a diaphragm housing(6) through the bush. If the negative pressure gets smaller, the diaphragm descends by the elastic repulsive force of the return spring. The opening of the valve seat is reduced or closed completely. A washer(15) is useful as a buffer even though vibration is generated from the frequent lifting of the diaphragm. Therefore, the working rod is not separated.

Description

EZ Valve

The present invention relates to an improvement in the structure of an EGR valve that can block thermal conduction and prevent deterioration of components.

Exhaust gas emitted from the engine contains a large amount of gaseous components such as HC, CO, and NOx that are harmful to the human body.

These harmful gas components are purified through catalytic converters, but the purification components vary depending on the operating conditions such as air-fuel ratio.

In the case of NOx, which is the most harmful to the human body, the emission temperature tends to increase as the temperature of the combustion chamber increases.

For this reason, part of the exhaust gas discharged through the exhaust system is returned to the combustion chamber and re-burned together with the mixer to lower the temperature of the combustion chamber to reduce the amount of NOx generated, and to burn and discharge unburned gas such as HC in the exhaust gas. The system is being applied to reduce emissions.

In the middle of the return line for guiding the exhaust gas to the intake manifold side, an EGR valve 1 having a structure as shown in FIG. 2 is provided to open and close the return line according to the engine operating conditions.

The EGR valve 1 is composed of a valve 4 for opening and closing the valve seat 3, an actuating rod 5, a diaphragm 11 for operating the actuating rod 5, a return spring 16, and the like. The vacuum chamber 13 of 11) communicates with the intake side so that the intake negative pressure of the engine acts.

Accordingly, if the intake negative pressure acting on the vacuum chamber 13 is greater than the repulsive force of the return spring 16, that is, when the operating speed of the engine is increased, the diaphragm 11 is sucked to compress the return spring 16 to the vacuum chamber 13 side. In this way, the EGR gas is supplied to the combustion chamber by opening the valve 4 at the end of the operating rod 5 away from the valve seat 3.

However, according to the conventional structure described above, since the EGR gas returned from the exhaust system is very high temperature, the heat conducted to the valve 4, the operating rod 5, the housing 2, and the ceramic filter 20 is transferred back to the diaphragm 11 side. In particular, there is a problem that deterioration of the diaphragm 11 and the like, which are particularly susceptible to heat, and premature wear of each unit due to backflow of carbon, thereby lowering durability.

Accordingly, the present invention has been proposed in view of the above problems, and an object thereof is to provide an EGR valve that can block heat conduction, prevent deterioration of a diaphragm, such as heat, and prevent carbon backflow, thereby improving durability.

In order to achieve the above object, the EGR valve of the present invention prevents the reverse flow of the bush and carbon provided in the valve housing to support and guide the valve for opening and closing the valve seat, the operating rod for operating the valve, and the axial movement of the operating rod. Comprising: a ceramic filter, a diaphragm for lifting and lowering the operating rod, an upper and lower disk member suitable for stacking inside and outside the diaphragm to fix the operating rod, and a return spring for supporting the diaphragm moving toward the vacuum chamber by intake negative pressure In the EGR valve

Characterized by interposing a heat insulating material blocking the heat conduction between the bush and the ceramic filter.

And according to claim 2 of the present invention, the fixing rod is reduced in diameter at the upper end of the operating rod, the fixing rod is fixed through the upper and lower disk member and the diaphragm, the valve between the lower end of the fixing rod and the lower disk member It is characterized in that the washer for preventing the separation.

1 is a view showing an EGR valve according to the present invention

2 is a conventional EGR valve

※ Explanation of codes for main parts of drawing

1: EGR valve 2: valve housing

3: valve seat 4: valve

5: working rod 6: diaphragm housing

8: stepped portion 9: fixed rod

10 lower disk member 11 diaphragm

12 upper disk member 13 vacuum chamber

14 Nut 15 Washer

16: return spring 17: inlet

18: bush 19: insulation

20: ceramic filter (mesh filter)

Hereinafter, the configuration and operation of the present invention will be described with reference to the accompanying drawings.

1 is a view showing an EGR valve according to the present invention.

In the middle of the return line for returning the exhaust gas from the exhaust system to the intake manifold side, a valve housing 2 for installing the EGR valve 1 is connected.

The valve housing 2 has a valve seat 3, and a valve 4 for opening and closing the valve seat 3 is formed at the lower end of the operating rod 5.

The upper end of the actuating rod 5 protrudes upward through the valve housing 2 and protrudes into the diaphragm housing 6, and the upper end of the actuating rod 5 forms the step 8 due to the reduction in diameter. The fixing rod 9 extends, and the fixing rod 9 sequentially penetrates the lower disk member 10, the diaphragm 11, and the upper disk member 12, and is fastened to the nut 14 at the vacuum chamber 13 side. It is fixed.

And the stainless steel washer 15 fitted to support the stepped part 8 of the lower end of the fixed rod 9 is interposed between the lower disk member 10. The washer 15 prevents the nut 14 from loosening, thereby preventing the fastening state of the fixing rod 9 from loosening.

The peripheral edge of the diaphragm 11 is clamped by the diaphragm housing 6, and the return spring 16 which supports the diaphragm 11 in the vacuum chamber 13 is provided.

The vacuum chamber 13 is connected to an intake machine, for example, a surge tank side, via an inlet port 17.

The bush 18, the heat insulator 19, and the ceramic filter 20 are fitted to the portion where the actuating rod 5 passes through the valve housing 2 to guide and support the up and down operation of the valve actuating rod 5. .

The bush 18 is formed of a graphite material subjected to heat oxidation at 450 ° C.

In the present invention as described above, when the intake negative pressure acts strongly on the vacuum chamber 13 and the diaphragm 11 sucks and moves to the vacuum chamber 13 side while compressing the return spring 16, the upper and lower disk members 12, 10 are lifted up. In conjunction with the valve 4 at the lower end of the operating rod 5 is spaced apart from the valve seat 3, the return line is opened to supply the exhaust gas to the intake side.

At this time, the high temperature exhaust gas passing through the inside of the housing 2 heats the valve 4, the operating rod 5, the housing 2 and in particular the ceramic filter 20 (mesh filter). The heat insulating material 19 is interposed between the bushes 18 to interrupt the conduction of heat to the diaphragm housing 6 via the bushes 18.

In addition, when the intake negative pressure decreases, the diaphragm 11 is lowered by the elastic force of the return spring 16 to reduce or close the opening amount of the valve seat 3.

Here, even if the diaphragm 11 moves up and down frequently and the vibration force acts, the washer 15 serves as a buffer to prevent loosening of the fastening state of the operating rod 5.

According to the present invention as described above to block the heat transfer in the middle by inserting an insulating material between the bush and the ceramic filter for supporting the valve operating rod and guide the vertical movement to prevent the heat caused by the EGR gas conduction to the weak diaphragm side. The mesh filter prevents backflow of carbon, which prevents the wear and durability of diaphragm and chamber parts from being deteriorated, and acts as an anti-loosening washer between the valve operation rod and the disk member for fixing the diaphragm. Unwinding due to vertical vibration is prevented.

Claims (2)

A valve for opening and closing the valve seat, an actuating rod for operating the valve, a bush provided in the valve housing to support and guide the axial movement of the actuating rod, a ceramic filter for preventing backflow of carbon, a diaphragm for raising and lowering the actuating rod, An EGR valve comprising: an upper and lower disk member suitable for stacking inside and outside of a diaphragm to fix the working rod, and a return spring for supporting the diaphragm moving toward the vacuum chamber by intake negative pressure. EGR valve, characterized in that between the bushing and the ceramic filter is interposed between a heat insulating material to block the heat conduction and a mesh filter to prevent backflow of carbon The method of claim 1, A fixed rod having a reduced diameter is extended to the upper end of the working rod, and the fixed rod is fixed through the upper and lower disc members and the diaphragm. EGR valve characterized in that.