A sealing structure for hot end EGR valve flange connection

Abstract

The utility model relates to a sealing structure of a flange connection of a hot end EGR valve, comprising: two butt flanges connected by bolts with water channels and air channels, a sealing gasket is arranged between the two butt flanges, the sealing gasket is a metal sealing gasket, and the metal sealing gasket is provided with a sealing ring of polymer material at the water channel. The utility model proposes that in order to prevent water and gas from communicating, the sealing gasket adopts different sealing structures in the water side and gas side cavities, wherein the gas side cavity is sealed with a metal gasket, which is resistant to high temperature and not easy to fail, and the water side cavity is sealed with a rubber ring because the coolant flows inside and the temperature is low, and the rubber compensation ability is strong, the sealing is good and not easy to fail, and the rubber ring of the water channel is vulcanized together with the metal gasket, which is easy to assemble, solves the problem that the performance of the sealing gaskets of the same material does not meet the requirements, and improves the service life of the sealing gasket.

Description

Technical Field

[0001] The utility model relates to a sealing structure of a hot end EGR valve flange connection, which is a valve structure used in an environmental protection system of an automobile engine and a structure on a flange connecting an EGR valve and an engine. Background Art

[0002] The EGR valve is divided into two types: cold end and hot end. In the hot end arrangement, the high-temperature engine exhaust gas passes through the EGR valve first and then through the cooler. At this time, the EGR valve has no function of directly cooling the exhaust gas. Therefore, the temperature of the flange connecting the EGR valve and the cooler is very high. The sealing structure used at the flange needs to have strong high temperature resistance.

[0003] The existing exhaust gas recirculation (EGR) system of automobile engines is compact in structure. Usually, the EGR valve and the cooler are connected together by a butt flange, and both a water channel and an air channel are provided in the flange. The advantage of this design is that it not only has a compact structure, but also can use the coolant in the water channel to cool the entire flange connection, thus improving the working environment of the cooler and the EGR valve.

[0004] The existing hot-end EGR valve arrangement EGR system generally uses a sealing gasket, or a metal gasket, or a high-temperature resistant non-metallic gasket, such as graphite, to seal at the valve and cooler flange connection. This sealing gasket prevents both exhaust gas leakage and coolant leakage. Metal gaskets have high rigidity and weak compensation ability, and cannot achieve good sealing. They are suitable for occasions with low requirements for leakage. In addition, metal gasket sealing has high requirements for the roughness and flatness of the flange surface. It is difficult to achieve that two cavities on the same flange surface are not interconnected. Therefore, metal gaskets are generally used for sealing a single channel under high temperature conditions, such as the flange seal of the engine exhaust manifold and the EGR valve; non-metallic gaskets such as graphite gaskets have high temperature resistance, and can achieve the purpose of sealing by compensating for the microscopic defects of the flange surface after compression. They have strong compensation ability and good initial sealing. However, graphite gaskets work at high temperatures for a long time and are prone to oxidation and weight loss. After the graphite gasket is compressed, the sealing medium will leak slightly through the interlayer gap after the graphite is compressed under high pressure. Coupled with the influence of high-temperature oxidation, the micro-leakage gradually turns into a large leak over time, and then fails.

[0005] Therefore, when a single gasket is used at the high temperature end, conventional rubber seals cannot meet the sealing requirements and will age and fail due to high temperature, leading to leakage risks. Especially when the water channel and the air channel are arranged on the same flange surface, there is a hidden danger of water and gas intercommunication. Once it fails, the coolant enters the air channel and then flows into the engine cylinder, causing cylinder scuffing and serious damage to the engine. How to avoid the risk of engine failure caused by seal damage between the hot end EGR valve and the cooler is a problem that needs to be solved. Summary of the invention

[0006] In order to overcome the problems of the prior art, the utility model proposes a sealing structure for the flange connection of the hot end EGR valve. The sealing structure uses different sealing materials in the air channel and the water channel to form different densities, which effectively reduces the risk of engine failure caused by sealing damage between the hot end EGR valve and the cooler.

[0007] The purpose of the utility model is achieved as follows: a sealing structure of a hot end EGR valve flange connection, comprising: two butt flanges with water channels and air channels connected by bolts, a sealing gasket is arranged between the two butt flanges, the sealing gasket is a metal sealing gasket, and the metal sealing gasket is provided with a sealing ring of a polymer material at the water channel.

[0008] Furthermore, the polymer material is rubber.

[0009] Furthermore, the sealing ring is fixed on the metal sealing gasket by vulcanization.

[0010] Furthermore, a step is provided at the junction of the metal sealing pad and the vulcanized and fixed rubber sealing ring.

[0011] Furthermore, a guide groove is provided on the flange between the water channel and the air channel.

[0012] Furthermore, the metal sealing gasket is a multi-layer sealing gasket.

[0013] Furthermore, the multi-layer sealing gasket includes: two layers of copper foil, upper and lower layers, and a paper material in the middle.

[0014] The advantages and beneficial effects of the utility model are as follows: in order to prevent water and gas from communicating, the utility model adopts different sealing structures in the water side and gas side cavities of the sealing gasket, wherein the gas side cavity is sealed with a metal gasket, which is resistant to high temperature and not easy to fail; the water side cavity has a low temperature due to the flow of coolant inside, and is sealed with a rubber ring, which has strong rubber compensation ability, good sealing and not easy to fail; and the rubber ring sealing the water channel is vulcanized together with the metal gasket, which is easy to assemble, solves the problem that the performance of sealing gaskets of the same material does not meet the requirements, and increases the service life of the sealing gasket. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 This is a schematic diagram of the sealing structure described in Embodiment 1 of the present utility model;

[0017] Figure 2 is a schematic diagram of the sealing gasket structure of the first embodiment of the utility model, Figure 1 Middle AA view;

[0018] Figure 3 It is a structural schematic diagram of the joint between the rubber sealing ring and the metal sealing gasket described in the fourth and seventh embodiments of the present utility model. Figure 2 Enlarged view of the cross section in the CC direction;

[0019] Figure 4 is a schematic diagram of the structure of the guide groove described in the sixth embodiment of the utility model, Figure 1 Middle BB view. DETAILED DESCRIPTION

[0020] Embodiment 1:

[0021] This embodiment is a sealing structure for the flange connection of the hot end EGR valve, such as Figure 1 , 2 This embodiment includes: two butt flanges 4 and 5 with water channel 2 and air channel 3 connected by bolts 1, and a sealing gasket 6 is arranged between the two butt flanges. The sealing gasket is a metal sealing gasket, and the metal sealing gasket is provided with a sealing ring 601 made of polymer material at the water channel. Figure 2 shown.

[0022] The flange connection described in this embodiment is a structure for connecting the cooler of the EGR system of the engine and the engine exhaust pipe. The engine exhaust pipe is also provided with a cooling water channel. The temperature of the exhaust pipe can be reduced by using the coolant. Therefore, there are both water channels and air channels on the flange. In order to ensure that both the high-temperature gas test side and the low-temperature water side can be well sealed, this embodiment adopts an integral metal gasket to resist high temperature, and at the same time, a sealing ring of a polymer material surrounding the water side is adopted on the water side. Due to the effect of the coolant on the water side, the sealing material can work at a relatively low temperature. The sealing ring of the polymer material can be a material such as rubber or plastic that can withstand high temperatures of 80 to 150 degrees. The sealing ring of the polymer material and the metal gasket can be connected by bonding or vulcanization fixing. In order to make the polymer material and the metal gasket firmly connected, the connection between the two can adopt structural forms such as steps and lock edges.

[0023] To prevent leakage of polymer sealing materials, a guide groove can be provided between the water channel and the air channel on the flange to isolate the water channel and the air channel. In this way, even if the seal on one side fails, the coolant can be discharged to the outside and will not enter the engine, thereby effectively reducing losses.

[0024] The metal sealing gasket can be in the form of two layers of copper foil with paper material sandwiched between them.

[0025] Embodiment 2:

[0026] This is an improvement of the first embodiment and a refinement of the first embodiment with respect to polymer materials. The polymer material described in this embodiment is rubber.

[0027] Rubber is a commonly used polymer sealing material with good elasticity, can withstand high temperatures of 150 degrees, and can work reliably for a long time without leakage.

[0028] Embodiment three:

[0029] This embodiment is an improvement of the above embodiment and a refinement of the rubber sealing ring of the above embodiment. The sealing ring described in this embodiment is fixed on the metal sealing pad by vulcanization.

[0030] Vulcanization fixation allows the sealing ring to be firmly fixed on the metal sealing ring, and can be combined with the metal sealing gasket in a more complex shape (such as steps, etc.).

[0031] Embodiment 4:

[0032] This embodiment is an improvement of the above embodiment and is a refinement of the above embodiment regarding the rubber sealing ring. A step 602 is provided at the junction of the metal sealing pad and the vulcanized and fixed rubber sealing ring described in this embodiment. Figure 3 shown.

[0033] Add steps on one side or both sides, such as Figure 3 As shown, the compression space of the sealing ring can be increased, so that the rubber sealing ring and the metal sealing gasket are firmly combined and are not easy to loosen.

[0034] Embodiment five:

[0035] This embodiment is an improvement of the above embodiment and a refinement of the flange of the above embodiment. The flange of this embodiment is provided with a guide groove 501 between the water channel and the air channel. Figure 4 shown.

[0036] In this embodiment, a guide groove is provided between the gas tester and the water side. Once the coolant leaks from the water side, it can be discharged through the guide groove without entering the gas tester. Figure 3 The flange shown has a guide groove on one side, but in practice, a guide groove may also be provided on the other side, so that coolant leakage can be prevented on both sides.

[0037] Embodiment six:

[0038] This embodiment is an improvement of the above embodiment and a refinement of the metal sealing gasket of the above embodiment. The metal sealing gasket described in this embodiment is a multi-layer sealing gasket.

[0039] High temperature metal gaskets can be in many forms, such as copper foil gaskets, metal gaskets with paper material between two layers of copper foil, etc.

[0040] Embodiment seven:

[0041] This embodiment is an improvement of the above embodiment and a refinement of the above embodiment regarding the multi-layer sealing gasket. The multi-layer sealing gasket described in this embodiment includes: two layers of copper foil 604, a paper material 605 in the middle, such as Figure 3 shown.

[0042] Finally, it should be noted that the above is only used to illustrate the technical solution of the utility model and is not a limitation. Although the utility model is described in detail with reference to the preferred arrangement scheme, ordinary technicians in the field should understand that the technical solution of the utility model (such as the form of the flange, the cooler or valve connected to the flange and the flange connection method, etc.) can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model.

Claims

1. A sealing structure for a hot end EGR valve flange connection, comprising: Two butt flanges with water channels and air channels connected by bolts, a sealing gasket is arranged between the two butt flanges, characterized in that the sealing gasket is a metal sealing gasket, and the metal sealing gasket is provided with a sealing ring made of polymer material at the water channel.

2. The sealing structure according to claim 1, characterized in that: The polymer material is rubber.

3. The sealing structure according to claim 2, characterized in that: The sealing ring is fixed on the metal sealing gasket by vulcanization.

4. The sealing structure according to claim 3, characterized in that: A step is provided at the junction of the metal sealing pad and the vulcanized and fixed rubber sealing ring.

5. The sealing structure according to any one of claims 1 to 4, characterized in that: The flange is provided with a guide groove between the water channel and the air channel.

6. The sealing structure according to claim 5, characterized in that: The metal sealing gasket is a multi-layer sealing gasket.

7. The sealing structure according to claim 6, characterized in that: The multi-layer sealing gasket comprises: two layers of copper foil, an upper layer and a lower layer, and a paper material in the middle.

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