EP2516834A1

EP2516834A1 - Bypass valve for vehicles

Info

Publication number: EP2516834A1
Application number: EP10757146A
Authority: EP
Inventors: Chang Hoon Lee; Kuk Chan Moon; Seong Jun Kim; Yun Su Kim; Kyung Min Lee; Ji Yong Lee
Original assignee: Unick Corp
Current assignee: Unick Corp
Priority date: 2010-07-08
Filing date: 2010-09-08
Publication date: 2012-10-31
Also published as: WO2012005406A1; KR101016191B1; CN102667128A; EP2516834A4

Abstract

Disclosed is a bypass valve for vehicles, which provides effective control of exhaust gas, permits effective use of an internal space of the bypass valve, and guarantees good durability of flaps and a shaft. The bypass valve includes a valve-housing coupled to an outlet of an EGR cooler, a first intake port formed on one side of the valve-housing and connected to a cooling passage of the EGR cooler, a second intake port on the one side of the valve-housing and connected to a bypass passage of the EGR cooler, an exhaust port on the other side of the valve-housing, a first transfer channel in the valve-housing to connect the first intake port to the exhaust port, a second transfer channel in the valve-housing to connect the second intake port to the exhaust port, a first flap rotatably disposed in the first transfer channel, and a second flap rotatably disposed in the second transfer channel. The first and second flaps selectively open or close the first and second transfer channels to allow some of exhaust gas from an exhaust manifold to be directly recirculated to an intake manifold or to be recirculated thereto after being cooled.

Description

BYPASS VALVE FOR VEHICLES

The present disclosure relates to a bypass valve for vehicles and, more particularly, to a bypass valve for vehicles, which provides effective control of exhaust gas, permits effective use of an internal space of the bypass valve, and guarantees good durability of flaps and a shaft.

Emissions generally refer to gas discharged through an exhaust pipe upon combustion of a gas mixture and contain harmful substances, such as carbon monoxide (CO), nitrogen oxide (NOx), unburned hydrocarbon (HC), and the like.

With regard to such harmful substances, the amount of nitrogen oxide is inversely proportional to the amount of carbon monoxide and hydrocarbon. Namely, nitrogen oxide generation is maximized while generation of carbon monoxide and hydrocarbon is minimized, when fuel is completely combusted.

Thus, as regulation concerning emissions of harmful nitrogen-containing emissions become increasingly strict, various solutions, including an exhaust gas recirculation (EGR) system, have been devised to reduce harmful substance emissions.

The EGR system reduces the amount of nitrogen oxide by minimizing output loss while lowering the peak combustion temperature through recirculation of some of emissions. More specifically, when an exhaust gas containing carbon dioxide (CO₂), which has a greater thermal capacity than nitrogen (N₂), is added in a proper ratio to a gas mixture, it is possible to lower the peak combustion temperature in an engine, so that the amount of nitrogen oxide can be lowered.

Fig. 12 is a schematic view of a general exhaust gas recirculation system. Next, the exhaust gas recirculation system will be described with reference to Fig. 12.

The exhaust gas recirculation system 10 includes recirculation pipes 42, 44 for recirculating some of an exhaust gas discharged through an exhaust manifold 20 to an intake manifold 30, and an EGR cooler assembly 50 disposed on the recirculation pipes 42, 44 to cool a recirculated exhaust gas.

The recirculation pipes 42, 44 include an inlet pipe 42 connected to one end of the EGR cooler assembly 50 to receive an inflow of high temperature exhaust gas, and an outlet pipe 44 connected to the other end of the EGR cooler assembly 50 to discharge the exhaust gas cooled through the EGR cooler assembly 50. On the inlet pipe 42, an EGR valve (not shown) for recirculating the exhaust gas and a bypass valve (not shown) for selectively passing the exhaust gas flowing through the inlet pipe 42 are disposed.

The EGR cooler assembly 50 is a shell & tube type heat exchanger and cools the high temperature exhaust gas, which flows therein through the inlet pipe 42, using a coolant from an engine 60. To this end, the EGR cooler assembly 50 is provided with an inflow tube 52, through which the coolant flows into the EGR cooler assembly 50, and a discharge tube 54 through which the coolant is discharged.

However, the bypass valve applied to the conventional EGR recirculation system 10 cannot provide effective control of the exhaust gas flow due to the complicate structure thereof, thereby causing very low utilization of an internal space in a valve-housing. Further, flaps for selective discharge of exhaust gas and associated components for operating the flaps are likely to suffer significant deterioration in durability by long period operation of the bypass valve.

The present disclosure is conceived to solve the above and other problems of the related art, and an aspect of the present disclosure provides a bypass valve for vehicles, which provides effective control of exhaust gas, permits effective use of an internal space of the bypass valve, and guarantees good durability of flaps and a shaft.

In accordance with an aspect of the present disclosure, a bypass valve for vehicles includes: a valve-housing coupled to an exhaust gas outlet of an EGR cooler; a first intake port formed on one side of the valve-housing and connected to a cooling passage of the EGR cooler; a second intake port formed on the one side of the valve-housing and connected to a bypass passage of the EGR cooler; an exhaust port formed on the other side of the valve-housing; a first transfer channel defined in the valve-housing and connecting the first intake port to the exhaust port; a second transfer channel defined in the valve-housing and connecting the second intake port to the exhaust port; a first flap rotatably disposed in the first transfer channel; and a second flap rotatably disposed in the second transfer channel.

In the bypass valve of this structure, the first and second flaps selectively open or close the first and second transfer channels to allow some of an exhaust gas discharged through an exhaust manifold to be directly recirculated to an intake manifold or to be recirculated thereto after being cooled to a predetermined temperature.

According to one embodiment of the present disclosure, the bypass valve for vehicles may provide, using a pair of flaps, effective control of an exhaust gas flowing into the bypass valve through the EGR cooler, and permit effective use of an internal space of the bypass valve using circular flaps. Further, the bypass valve is configured to allow smooth rotation of the flaps, thereby eliminating malfunction or deformation even after a long period of operation.

Figs. 1 and 2 are perspective views of a bypass valve for vehicles according to an exemplary embodiment of the present disclosure;

Fig. 3 is a perspective view of the bypass valve for vehicles according to the embodiment of the present disclosure, showing an inner configuration of the bypass valve;

Fig. 4 shows a shaft and flaps of the bypass valve for vehicles according to the embodiment of the present disclosure;

Figs. 5 and 6 show a coupling structure of the shaft in the bypass valve for vehicles according to the embodiment of the present disclosure;

Fig. 7 shows a rear side of the bypass valve for vehicles according to the embodiment of the present disclosure;

Figs. 8 and 9 show the bypass valve for vehicles according to the embodiment of the present disclosure, when coupled to an EGR cooler and when separated therefrom, respectively;

Figs. 10 and 11 show operating processes of the bypass valve for vehicles according to the embodiment of the present disclosure; and

Fig. 12 is a schematic view of a general exhaust gas recirculation system.

Exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In illustration of the embodiments, like elements will be denoted by like reference numerals throughout the drawings.

Figs. 1 and 2 are perspective views of a bypass valve for vehicles according to an exemplary embodiment, Fig. 3 is a perspective view of the bypass valve for vehicles according to the embodiment, showing an inner configuration of the bypass valve, Fig. 4 shows a shaft and flaps of the bypass valve for vehicles according to the embodiment, Figs. 5 and 6 show a coupling structure of the shaft in the bypass valve for vehicles according to the embodiment, and Fig. 7 shows a rear side of the bypass valve for vehicles according to the embodiment.

Referring to Figs. 1 to 3, a bypass valve 100 for vehicles according to this embodiment includes a valve-housing 110, a shaft 120 and flaps 130 disposed inside the valve-housing 110, and a drive mechanism 140 disposed outside the valve-housing 110 to rotate the shaft 120 to which the flaps 130 are secured.

The valve-housing 110 is formed at one side thereof with intake ports 112a, 112b, through which exhaust gas is introduced into the valve-housing 110, and is formed at the other side thereof with an exhaust port 114 through which the exhaust gas is discharged from the valve-housing 110. Further, transfer channels 116a, 116b are formed in the valve-housing 110 to connect the intake ports 112a, 112b to the exhaust port 114.

The intake ports 112a, 112b include a first intake port 112a connected to a cooling passage 210 (see Figs. 8 and 9) of the EGR cooler 200 (see Figs. 8 and 9) and a second intake port 112b connected to a bypass passage 220 (see Figs. 8 and 9) of the EGR cooler 200. Further, the transfer channels 116a, 116b include a first transfer channel 116a connecting the first intake port 112a to the exhaust port 114, and a second transfer channel 116b connecting the second intake port 112b to the exhaust port 114.

Here, flaps 130 are disposed between the first and second transfer channels 116a, 116b for selective discharge of the exhaust gas flowing in the valve-housing 110 through the first and second intake ports 112a, 112b. That is, when one of the transfer channels 116a, 116b is opened using the flaps 130, the exhaust gas is introduced into the valve-housing 110 only through the intake port 112a or 112b, which is connected to the opened transfer channel 116a or 116b. For example, when the first transfer channel 116a is opened, an exhaust gas cooled through the cooling passage 210 of the EGR cooler 200 is introduced through the first intake port 112a, and when the second transfer channel 116b is opened, an exhaust gas by-passed through the bypass passage 220 of the EGR cooler 200 is introduced through the second intake port 112b.

As shown in Figs. 3 and 4, the shaft 120 has a rod shape of a predetermined length to be disposed in the valve-housing 110 through the first and second transfer channels 116a, 116b.

The flaps 130 include a first flap 132 located on the first transfer channel 116a and a second flap 134 located on the second transfer channel 116b. Each of the flaps 130 has a thin circular plate shape (disc shape) and is formed at the middle thereof with a mounting groove 132a or 134a, which is formed with a joining hole 132b or 134b.

The first and second flaps 132, 134 are disposed at a right angle relative to each other so that the second transfer channel 116b can be closed when the first transfer channel 116a is opened, and vice versa.

With this configuration, the first and second flaps 132, 134 occupy a smaller space in the valve-housing 110 than a conventional rectangular flap. In particular, since the first and second flaps 132, 134 are disposed on the first and second transfer channels 116a, 116b, respectively, the flow of exhaust gas may be more effectively controlled than in the case of using a single flap. Further, since the shaft 120, acting as a central axis of rotation, is coupled to the middle portions of the first and second flaps 132, 134, the flaps have a smaller turning radius than a conventional swing type flap, thereby enabling effective use of an internal space of the valve-housing 110.

The first and second flaps 132, 134 are secured to the shaft 120 through the mounting grooves 132a, 134a and the joining holes 132b, 134b. That is, with the shaft 120 inserted into the mounting grooves 132a, 134a, the first and second flaps 132, 134 are secured to the shaft 120 by laser welding through the joining holes 132b, 134b. In this manner, when the first and second flaps 132, 134 are secured to the shaft 120 by laser welding, there is no need to form a flap mounting surface on the shaft 120, thereby facilitating manufacture of the bypass valve while preventing stress concentration to enhance durability of the shaft 120.

Next, referring to Figs. 3 and 5 to 7, a coupling structure of the shaft 120 will be described.

Dry bearings 152, 154 are coupled to opposite ends of the shaft 120. The dry bearings 152, 154 are inserted into and secured to first and second mounting holes 118a, 118b formed on front and rear surfaces of the valve-housing 110. The first mounting hole 118a is provided with a shaft seal 156a and a seal plate 156b, and the second mounting hole 118b is provided with a stopper ring 158a and a locking cap 158b in order to prevent separation of the shaft 120 and leakage of exhaust gas.

The locking cap 158b may be made of the same material, for example, aluminum, as that of the valve-housing 110. In the case where the locking cap 158b is made of a different material than the valve-housing 110, a gap can be formed between the valve-housing 110 and the locking cap 158b due to difference in coefficient of thermal expansion, thereby causing leakage of the exhaust gas therethrough.

Further, after inserted into the second mounting hole 118b, the locking cap 158b is secured thereto by punching. In particular, as shown in Fig. 7, when punching points are radially formed along a circumference of the locking cap 158, the locking cap 158b may be effectively secured thereto.

One end of the shaft 120 is exposed from the valve-housing 110 through the first mounting hole 118a. The one end of the shaft 120 exposed outside is coupled to a rotational plate 142. The rotational plate 142 is connected to the drive mechanism 140 through a tappet 144 and is rotated to rotate the shaft 120 during operation of the drive mechanism 140.

The drive mechanism 140 is a general actuator operated by a negative pressure of an engine, and a detailed description thereof will be omitted herein.

Figs. 8 and 9 show the bypass valve for vehicles according to the embodiment, when coupled to an EGR cooler and when separated therefrom, respectively, and Figs. 10 and 11 show operating processes of the bypass valve for vehicles according to the embodiment.

As shown in Figs. 8 and 9, the bypass valve 100 of the embodiment is disposed at an exhaust gas outlet of the EGR cooler 200. That is, the bypass valve 100 is disposed to allow an exhaust gas from an exhaust manifold (not shown) to flow through the cooling passage 210 of the EGR cooler 200 or through the bypass passage 220 by selectively opening the first and second transfer channels 116a, 116b according to a negative pressure of the engine in the vehicle.

More specifically, when the drive mechanism 140 is operated by a negative pressure of the engine, the tappet 144 is moved to rotate the rotational plate 142, which in turn rotates the shaft 120 and the first and second flaps 132, 134.

Here, the first and second flaps 132, 134 selectively open one of the first and second transfer channels 116a, 116b. For example, when the first transfer channel 116a is opened, the second transfer channel 116b is closed, so that the exhaust gas is introduced in a cooled state into the valve-housing through the first intake port 112a via the cooling passage 210 of the EGR cooler 200. On the other hand, when the second transfer channel 116b is opened, the first transfer channel 116a is closed, so that the exhaust gas is introduced in a non-cooled state into the valve-housing through the second intake port 112b via the bypass passage 220 of the EGR cooler 200.

When the flow of exhaust gas is controlled by the process described above, it is possible to maintain the temperature of the exhaust gas discharged through the exhaust port 114 of the bypass valve 100.

On the other hand, in Figs. 10 and 11, reference numerals 230 and 240 indicate an inlet of the EGR cooler 200 through which a coolant for cooling the exhaust gas flowing through the cooling passage 210 is introduced into the EGR cooler 200, and an outlet of the EGR cooler 200 through which the coolant is discharged from the EGR cooler 200, respectively.

Although some embodiments have been provided to illustrate the invention, it should be noted that the embodiments are given by way of illustration only and do not limit the scope of the present invention, and it will be apparent to those skilled in the art that various modifications, changes, and substitutions can be made without departing from the spirit and scope of the invention. Therefore, the scope and sprit of the invention should be interpreted only by the following claims and equivalents thereof.

Claims

A bypass valve for vehicles comprising:

a valve-housing coupled to an exhaust gas outlet of an EGR cooler;

a first intake port formed on one side of the valve-housing and connected to a cooling passage of the EGR cooler;

a second intake port formed on the one side of the valve-housing and connected to a bypass passage of the EGR cooler;

an exhaust port formed on the other side of the valve-housing;

a first transfer channel defined in the valve-housing and connecting the first intake port to the exhaust port;

a second transfer channel defined in the valve-housing and connecting the second intake port to the exhaust port;

a first flap rotatably disposed in the first transfer channel; and

a second flap rotatably disposed in the second transfer channel,

the first and second flaps selectively opening or closing the first and second transfer channels.
The bypass valve of claim 1, further comprising:

a shaft disposed in the valve-housing to penetrate the first and second transfer channels, the first and second flaps being coupled to the shaft; and

a drive mechanism provided to one end of the shaft and rotating the first and second flaps.
The bypass valve of claim 2, wherein the first and second flaps are disposed at a right angle relative to each other to close the second transfer channel when the first transfer channel is opened, and to open the second transfer channel when the first transfer channel is closed.
The bypass valve of claim 3, wherein the first and second flaps have a circular shape and are formed with mounting grooves into which the shaft is inserted.
The bypass valve of claim 4, wherein the first and second flaps are secured to the shaft by laser welding.
The bypass valve of claim 5, wherein the valve-housing is formed at front and rear surface thereof with first and second mounting holes, to which dry bearings are provided, and the shaft is rotatably coupled at opposite ends thereof to the dry bearings, respectively.
The bypass valve of claim 6, further comprising: a shaft seal and a seal plate provided to the first mounting hole.
The bypass valve of claim 6 or 7, further comprising: a stopper ring and a locking cap provided to the second mounting hole.
The bypass valve of claim 8, wherein the locking cap is inserted into the second mounting hole and secured thereto by punching.
The bypass valve of claim 9, wherein the locking cap is made of a material having the same coefficient of thermal expansion as the valve-housing.