Patent Application
20100242927
The present disclosure relates generally to seal rings. More specifically, the present disclosure relates to a seal ring for an exhaust gas recirculation (EGR) system.
In modern internal combustion engines, the air flow in the intake system and/or the exhaust gas flow in the exhaust gas system are controlled or regulated by electronically controlled valve devices. The appropriate valve devices are, for example, a throttle valve, and exhaust gas recirculation (EGR) valve, a bypass valve of a supercharger, etc. Such valve devices normally include a channel through which the air stream and the exhaust gas stream flow, a rotatable or displaceable valve element which controls the flow quantity as a function of its setting, an electrical actuating device, for instance a DC motor, a mechanical connection between the valve element and the actuating device, a sensor that records the current setting of the valve element, and a control and regulation device that ascertains the actuating signal that is applied to the actuating device in order to obtain a desired position of the valve element.
EGR valves are a major part of anti-pollution devices on the internal combustion engines of present day vehicles. EGR valves are attached to the exhaust manifold where the crossover pipe leads to the intake manifold. At that point, the valve is inserted into the exhaust manifold through a pre-existing hole to regulate the amount of exhaust entering the intake manifold. This cools the peak combustion temperature, provides a better burn of the gas, and reduces NOx emissions.
In an exemplary embodiment, a ring seal assembly can include a ring and a seal. The ring can have a proximal end including a major lip and a distal end including a minor lip. Additionally, the ring can have a seal contacting region between the major lip and the minor lip. Further, the ring can have an inner surface defining a central bore. Within the seal contacting region, the central bore can have a radius that decreases along a direction extending from the minor lip to the major lip. The seal can have a ring contacting outer portion and a shaft contacting inner portion. The ring contacting outer portion can be shaped to be complementary to the inner surface of the seal contacting region of the ring and a shaft contacting inner portion can be configured to contact a shaft placed within the central bore of the ring.
In another exemplary embodiment, an EGR valve system can include an actuator, a shaft coupled to the actuator, and a valve disk coupled to the shaft. The valve disk can be configured to regulate an amount of exhaust gas being passed to an intake manifold. Additionally, the EGR valve system can include a ring seal assembly placed on the shaft to substantially limit the amount of exhaust gas that contacts the actuator. The ring seal assembly can include a ring and a seal. The ring can have a proximal end including a major lip and a distal end including a minor lip. Additionally, the ring can have a seal contacting region between the major lip and the minor lip. Further, the ring can have an inner surface defining a central bore. Within the seal contacting region, the central bore can have a radius that decreases along a direction extending from the minor lip to the major lip. The seal can have a ring contacting outer portion and a shaft contacting inner portion. The ring contacting outer portion can be shaped to be complementary to the inner surface of the seal contacting region of the ring and a shaft contacting inner portion can be configured to contact a shaft placed within the central bore of the ring.
In a further exemplary embodiment, a method of operating an internal combustion engine can include receiving an exhaust gas from an internal combustion engine, mixing a portion of the exhaust gas with air to form an intake gas mixture, and providing the intake gas to the internal combustion engine. Additionally, the method can include controlling the ratio of the exhaust gas to air by activating an actuator, and protecting the actuator from the exhaust gas. In order to control the ratio of exhaust gas to air, the actuator can move a shaft attached to a valve disk in order to alter the amount of exhaust gas added to the intake gas mixture. The actuator can be protected from the exhaust gas by using a ring seal assembly located on the shaft between the valve disk and the actuator. The ring seal assembly can include a ring and a seal. The ring can have a proximal end including a major lip and a distal end including a minor lip. Additionally, the ring can have a seal contacting region between the major lip and the minor lip. Further, the ring can have an inner surface defining a central bore. Within the seal contacting region, the central bore can have a radius that decreases along a direction extending from the minor lip to the major lip. The seal can have a ring contacting outer portion and a shaft contacting inner portion. The ring contacting outer portion can be shaped to be complementary to the inner surface of the seal contacting region of the ring and a shaft contacting inner portion can be configured to contact a shaft placed within the central bore of the ring.
The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings.
The use of the same reference symbols in different drawings indicates similar or identical items.
The seal 110 can be an annular seal having a passage 126 formed through the center. The seal include an outer portion 128 and an inner portion 130. The outer portion 128 can contact the inner surface 122 of the ring 108 within the seal contacting region 120. The inner portion 130 can be located adjacent to the passage 126 and can be substantially free of contact with the ring 108. In an embodiment, the seal 110 can have a flattened V-shaped cross section as shown. That is, the seal 110 can have a flattened joining region 132, rather than a pointed vertex, where the inner portion 130 and the outer portion 128 meet. Alternatively, the seal 110 can have a U-shaped cross section having a curved joining region or a V-shaped cross section having a pointed vertex at the joining region.
When assembled, the seal 110 can be generally contained within the seal contacting region 120 and held in place between the major lip 114 and the minor lip 118. Further, the inner portion 130 of the seal can contact the inner surface of the seal contacting region 120 of the ring along substantially the entire length of the seal contacting region 120, thereby preventing the formation of a void space between the seal 110 and the ring 108.
In an embodiment, the ring 108 can be formed of a substantially rigid material, such as brass, steel, and certain plastics. The seal 110 can be formed of a semi-rigid or flexible material, such as certain natural and synthetic polymers. For example, the seal can include polytetrafluoroethylene (PTFE), rubber, latex, polyethylene, polyamide, and the like. Further, the seal can include fillers and additives known to modify certain physical properties, such as rigidity, wear resistance, thermal stability, and chemical resistance, of the polymer.
In an embodiment, the ring seal 100 and sealed shaft assembly 200 can be used in an EGR valve, as described in more detail below. Alternatively, the ring seal 100 can be used in other applications, where a translating or rotating shaft passes through a barrier or wall and contamination needs to be substantially prevented from passing through the barrier or wall. Contamination can include liquids, gasses, or particulate material, such as dust. Additionally, the ring seal 100 can be used in applications typically known to use spring biased seals. In an embodiment, the ring seal 100 can have an average leakage rate of less than about 4.0 ml/min, such as less than about 3.0 ml/min, less than about 2.0 ml/min, even less than about 1.0 ml/min.
The valve body 302 can include an exhaust gas inlet 322 and an exhaust gas outlet 324. The exhaust gas inlet 322 can be in fluid communication with an exhaust manifold of an internal combustion engine and the exhaust gas outlet 324 can be in fluid communication with an intake manifold of the internal combustion engine. In a closed position, the plate seals 308 and 310 can separate the exhaust gas inlet 322 from the exhaust gas outlet 324 and can substantially prevent exhaust gases passing from the exhaust manifold to the intake manifold. In an open position, the valve stem 304 can be translated towards the proximal end 314 of the EGR valve 300 causing the plate seals 308 and 310 to open and allow passage of exhaust gas from the exhaust gas inlet 322 to the exhaust gas outlet 324. Accordingly, the exhaust gas from the internal combustion engine can be recirculated from the exhaust manifold to the intake manifold.
During operation, an actuator (not shown), such as an electric motor, a solenoid, or a pneumatic actuator, can move the EGR valve 300 between the open and closed positions, thereby controlling the amount of exhaust gas recirculated from the exhaust manifold to the intake manifold. The recirculated exhaust gas can be mixed with air to form an intake gas prior to reaching the internal combustion engine. The recirculated exhaust gas can reduce the amount of oxygen in the intake gas, thereby cooling the operating temperature of the internal combustion engine and can reduce NOx emissions. Additionally, the ring seal can substantially reduce the amount of exhaust gasses that contact the actuator and increase the lifetime of the actuator and the EGR valve 300, thereby reducing maintenance costs.
The samples are assembled within an EGR valve test rig. Average leakage rates are determined by applying a pressure of 1 bar to the exhaust gas inlet and exhaust gas outlet and measuring the flow across the ring seal using a flow meter. The results are shown in Table 1.
Comparative Sample 1 includes a ring having a substantially constant radius within the seal contacting region, as shown in
Sample 1 includes a ring having a linearly decreasing radius within the seal contacting region along a distance from the minor lip to the major lip, as shown in
Sample 2 is the same as Sample 1, except sample 2 is a serial production run of 100 ring seals.
The present application claims priority from U.S. Provisional Patent Application No. 61/164,691, filed Mar. 30, 2009, entitled “SEAL RING FOR EXHAUST GAS RECIRCULATION SYSTEM,” naming inventors Torsten Recktenwald and Tibor Moeller, which application is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61164691 | Mar 2009 | US |
