KR101405550B1 - Pulse switching Exhaust Gas Recirculation apparatus - Google Patents

Abstract

The present invention applies a pulse switching valve and a one-way valve and extracts only the exhaust pressure higher than the intake boost pressure to recirculate the EGR gas to the intake manifold, thereby preventing backflow of EGR gas due to supercharging of high pressure in the engine to which the turbocharger is applied To a pulse switching exhaust gas recirculation device capable of reducing knock and reducing pumping loss as well as improving NOx reduction efficiency.

Description

[0001] Pulse switching exhaust gas recirculation apparatus [0002]

The present invention relates to a pulse switching exhaust gas recirculation device capable of reducing knock suppression, knock reduction, and pumping loss.

The vehicle is provided with an exhaust gas recirculation (hereinafter referred to as EGR) device for recirculating a part of the exhaust gas to the intake system to suppress the generation of NOx.

In the exhaust gas flow path of the automobile engine to which the EGR device is applied, the intake air flowing into the cylinder according to the opening of the intake valve is mixed with the fuel and burned, and then discharged into the exhaust manifold according to the opening of the exhaust valve.

Subsequently, a part of the exhaust gas emitted from the exhaust manifold is recirculated to the intake manifold through the EGR hose in accordance with the opening of the EGR valve, while the remaining exhaust gas is exhausted toward the exhaust pipe.

As described above, the EGR device reduces NOx generated during combustion by introducing a part of the exhaust gas into the engine, thereby lowering the temperature in the cylinder.

The turbocharger, which is also referred to as a so-called turbocharger, is attached to an exhaust manifold of the engine and drives the turbine using exhaust gas discharged from the engine. The air from the turbocharger is supplied to an intercooler intercooler) and then supplied to the engine again.

Since the turbocharger is connected to the turbine and the compressor by a single shaft, when the exhaust gas to the exhaust muffler collides with the turbine side and the turbine is turned, the compressor connected to the shaft rotates together to suck and compress the fresh air outside, By forcibly pushing it, the volume effect of the cylinder is increased, and the effective pressure ratio and the explosion pressure are also increased, and the output is improved.

However, in a general supercharging engine, the intake boost pressure is higher than the exhaust pressure, so that the EGR gas can not be supplied to the intake side but rather flows backward, resulting in a problem of deterioration of NOx reduction efficiency.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide an engine in which a turbo supercharger is applied by employing a pulse switching valve and a one way valve and recirculating EGR gas to an intake manifold by extracting only an exhaust pressure higher than an intake boost pressure And it is an object of the present invention to provide a pulse switching exhaust gas recirculation device capable of preventing backflow of EGR gas due to supercharging of high pressure and improving NOx reduction efficiency as well as suppressing knock and reducing pumping loss .

According to an aspect of the present invention, there is provided an exhaust gas recycling apparatus including: an engine having a plurality of cylinders; An exhaust manifold for bifurcating the exhaust gas discharged from the cylinder; A pulse switching valve connected to the exhaust manifold for selectively opening and closing a flow passage of the exhaust gas branched in two directions; And a one-way valve installed in an exhaust gas recirculation line between the exhaust manifold and the intake system of the engine to prevent reverse flow of recirculated exhaust gas.

Wherein the exhaust manifold is constituted by first and second exhaust manifolds respectively connecting the cylinders in a branch structure and the cylinders of the first exhaust manifold and the cylinders of the second exhaust manifold are alternately So as to be ignited.

The cylinders are divided into two groups by an exhaust manifold. When the number of cylinders is an even number, the exhaust manifolds of each group are symmetrical. When the number of cylinders is odd, the exhaust manifolds of the groups are asymmetrically structured The exhaust gas from any one of the cylinders of the group of cylinders having a larger number of cylinders can be discharged directly through the exhaust pipe without recirculation.

The pulse switching valve and the one-way valve are installed in a valve body having a T-shaped body. The valve body is formed on both sides of the valve body so that a first port and a second port for introducing exhaust gas into the valve body, And a third port formed in a direction opposite to the first port and the second port to discharge the exhaust gas, wherein the first port and the second port are selectively opened and closed by the operation of a pulse switching valve, The port is characterized in that the exhaust gas can be discharged only in one direction by the one-way valve.

And the pulse switching valve and the one-way valve are separately provided separately from each other.

Advantages of the pulse switching exhaust gas recirculation apparatus according to the present invention are as follows.

First, a pulse switching valve and a one-way valve are applied on the recirculation line to extract the exhaust pressure higher than the intake pressure in the exhaust manifold, so that in the EGR system in which the supercharging engine is applied, the EGR gas is recirculated .

Second, it is possible to prevent backflow of the exhaust gas due to intake air compression of the turbo supercharger, thereby reducing knocking, knock reduction and pumping loss.

1 is a schematic diagram of an exhaust gas recirculation apparatus according to the present invention
Figs. 2 to 4 are diagrams showing operating states of the pulse switching valve and the one-way valve according to the pressure difference in Fig.
FIG. 5 is a graph showing a pressure curve for explaining extraction of an exhaust gas having an exhaust pressure higher than an intake pressure according to the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be easily understood by those skilled in the art.

1 is a configuration diagram of an exhaust gas recirculation apparatus according to the present invention.

The present invention relates to a pulse switching exhaust gas recirculation device capable of preventing backflow of EGR gas.

Particularly, in the exhaust gas recirculation apparatus according to the present invention, when a part of the exhaust gas is recirculated to the intake manifold 1 in the supercharged engine 2 equipped with the turbocharger 16, The knock suppression, the knock reduction, and the pumping loss can be reduced.

To this end, the present invention is characterized in that a pulse switching valve 7 and a one-way valve 8 (not shown) are provided on the EGR line in which the exhaust gas discharged from the exhaust manifold 6 is recirculated to the intake manifold 1 it is possible to prevent the reverse flow phenomenon of the EGR gas by extracting only the exhaust pressure higher than the compressed intake pressure from the supercharger 16 by using the oneway valve.

Currently, an internal combustion engine such as a gasoline and diesel engine 2 has a plurality of cylinders 3, and fuel and air are supplied into the combustion chambers of the respective cylinders 3, where combustion is performed through ignition to generate explosive power And the exhaust gas is exhausted to the exhaust manifold 6.

At this time, the cylinders 3 are ignited at the same time, but ignition is performed in a predetermined order.

For example, an example showing the ignition sequence according to the number of cylinders 3 is shown in Table 1 below.

The number in the ignition sequence in Table 1 is the number of the cylinder 3 attached to the manufacturer in accordance with the number of the cylinders 3 of each engine 2 and this is only one example for explaining the present invention and does not limit the present invention .

In the branch structure in Table 1, the exhaust port of each cylinder 3 is connected to the two exhaust manifolds 6, and the exhaust gas discharged from the plurality of cylinders 3 is connected to the two exhaust manifolds 6, To the exhaust system structure.

In the conventional exhaust system, the exhaust gas discharged from the plurality of cylinders 3 is connected to one exhaust manifold and exhausted to the exhaust pipe 15. However, the exhaust system according to the present invention is not limited to the exhaust gas discharged from the plurality of cylinders 3 And branching to the two exhaust manifolds 6.

The branch structure is a term cited from the shape of a branch.

Here, the exhaust system (exhaust manifold 6) of the branch structure according to the present invention is divided into two groups by connecting the cylinders 3 on the basis of the ignition sequence of each cylinder 3, for example, four cylinders In the case of the cylinder 3, the first exhaust manifold 4, which is one of the two exhaust manifolds 6, binds the cylinders 3 of which ignition is first and third, and the second exhaust manifold 4, (5) binds the cylinders (3) of which the ignition is the second and fourth.

For example, when four cylinders 3 are arranged on the same line from the left in the order of # 1, # 2, # 3, and # 4 cylinders 3 When the ignition sequence of each cylinder 3 in the four-cylinder engine 2 is performed in the order of # 1 → # 3 → # 4 → # 2, the first exhaust manifold 4 is connected to the first and fourth cylinders 3 And the second exhaust manifold 5 binds the cylinders 2 and 3 to the cylinder 3 and the second exhaust manifold 4 of the first exhaust manifold 4 5 are alternately ignited.

The reason why the cylinders 3 of the first and second exhaust manifolds 4 and 5 are alternately ignited is as follows.

The ignition sequence of the engine is performed in the order of 1-3-4-2. If all of the cylinders 3 of the engine are connected to one exhaust manifold, the third cylinder 3, then the third cylinder 3, The exhaust pressure is overlapped at the time of exhausting the third exhaust gas before the completion of the exhaust of the first exhaust gas, so that the exhaust gas is not good and the engine output is lowered.

Therefore, by separating the exhaust manifolds 4 of the first and fourth cylinders 3 from the exhaust manifolds 5 of the second and third exhaust manifolds 5, And the engine output can be raised.

In connection with the connection structure of each cylinder 3 according to the number of cylinders 3 of the engine 2 in Table 1, when the number of cylinders is two, the first exhaust manifold 4 (branch A) Folds 5 (branch B), and the number of cylinders is four, as described above.

In the Inline 6 engine 2 in which the number of cylinders is 6 and the cylinder arrangement is linear, the cylinder 3 is arranged in the order of 1, 2, 3, 4, 5 and 6 from the left The cylinder 3 connected by the first exhaust manifold 4 is No. 1, No. 2, No. 3 and No. 2 is the No. 3 exhaust manifold 4 when the ignition sequence is 1-4-3-6-2-5. The cylinders 3 connected by the fold 5 are No. 4, No. 5 and No. 6.

The exhaust system of the V6 engine 2 also has the same branch structure as the inline 6 engine 2, LH bank refers to the group 3 (Left Head Bank) of the cylinder head located on the left side, RH bank refers to the cylinder head And the cylinder (3) of the group on the right side.

The exhaust system of the V8 engine 2 has eight cylinders and a cylinder arrangement of V shape. The cylinders 3, 4, 6 and 7 are located on the left LH bank and 2 cylinders The first exhaust manifold 4 and the second exhaust manifold 4 are arranged in the order of 1-5-4-2-6-3-7-8, The first, second, and third cylinders 3, 3, 5, and 8 are connected by the second exhaust manifold 5, respectively.

Here, the branch structure has first and second exhaust manifolds 4 and 5 for dividing the plurality of cylinders 3 into two groups on the basis of the order of ignition of each cylinder 3 irrespective of the number of cylinders, , 5) are alternately ignited.

At this time, even when the number of cylinders is an odd number, it is possible to have two branch structures. For example, in the case of three or five cylinders 3, one of the two branches has one more cylinder 3 connected thereto , The exhaust gas discharged from the remaining one cylinder 3 can be directly drawn to the muffler so that the exhaust pressure can not be applied to the two branches.

Otherwise, if the number of cylinders 3 is odd, the branch structure may be asymmetric. For example, in one of the five cylinders 3, one branch connects two cylinders 3 and the other branch And the remaining three cylinders 3 may be connected.

The pulse switching exhaust gas recirculation apparatus according to the present invention divides the exhaust gas discharged from each cylinder 3 through the two exhaust manifolds 6 and divides a part of the exhaust gas in each exhaust manifold 6 into separate A T-shaped valve body 9 for collecting the exhaust gas into a single point, and a pulse switching unit 9 for selectively opening only the exhaust gas having a relatively high exhaust pressure, Thereby providing a valve 7.

The T-shaped valve body 9 consists of an inlet pipe 9a for collecting the separated fluid in one place and a discharge pipe 9b formed in one direction in the middle of the inlet pipe 9a.

The inlet pipe 9a has a first port 10a connected to the first exhaust manifold 4 through a first connection hose and a second port 10b connected to the second exhaust manifold 5 through a second connection hose. And a third port 10c connected to the intake manifold 1 through a third connection hose is formed in the discharge pipe 9b.

The recirculated exhaust gas flows into the valve body 9 from the first and second exhaust manifolds 4 and 5 through the first port 10a and the second port 10b, And recycled to the intake manifold 1 through the third port 10c.

The inlet pipe 9a has a connecting flow passage therein so that the first port 10a and the second port 10b, which are separated from each other, meet with each other. A valve operating section is formed in the middle of the connecting flow passage, Communicate with the first port 10a and the second port 10b, respectively.

The valve operating portion has a ball type pulse switching valve 7 whose diameter is relatively smaller than that of the valve operating portion. The diameter of the connecting flow path communicating with the first and second ports 10a and 10b is larger than the diameter of the ball And the length of the valve operating portion is longer than the diameter of the ball.

FIGS. 2 to 4 are operation states of the pulse switch valve and the one-way valve according to the pressure difference in FIG.

When the exhaust pressure of either one of the exhaust gas flowing in the first exhaust manifold 4 and the exhaust gas flowing in the second exhaust manifold 5 is larger, When the pulse switching valve 7 moves from one port to the other port of the first and second ports 10a and 10b in the operation part, the port with the larger exhaust pressure is opened.

For example, when the pressure of the exhaust gas flowing into the first port 10a is larger than the pressure of the exhaust gas flowing into the second port 10b, the pulse switching valve 7 is moved in the direction of the second port 10b The second port 10b is closed and a gap is formed at the other end of the valve operation portion to open the first port 10a.

On the contrary, when the pressure of the exhaust gas flowing into the second port 10b is larger than the pressure of the exhaust gas flowing into the first port 10a, the pulse switching valve 7 is moved in the direction of the first port 10a The first port 10a is closed by being in close contact with the other end of the valve operating portion and a gap is formed at one end of the valve operating portion to open the second port 10b.

Here, the pressure of the exhaust gas flowing through the first and second ports 10a and 10b is larger than the pressure of the intake air by supercharging.

As described above, the pulse switching valve 7 is moved by the pressure difference of the exhaust gas flowing into the first and second ports 10a and 10b to selectively supply the exhaust gas from the first and second exhaust manifolds 4 and 5 Lt; / RTI >

At this time, the reason why the two ports 10a and 10b are selectively opened by using the pulse switching valve 7 is to increase the extraction amount of the EGR gas.

In the absence of the pulse switching valve 7, the exhaust gas generated from the first exhaust manifold 4 may move from the first port 10a to the discharge pipe 9b, but the second exhaust gas may flow through the second port 10b, The pressure of the exhaust gas drops due to the movement toward the manifold 5 and the pressure of the exhaust gas generated in the first exhaust manifold 4 is canceled by the pressure of the exhaust gas generated in the second exhaust manifold 5 So that the extraction amount of the EGR gas is lowered.

The discharge pipe 9b has a hollow portion formed therein, a communication hole connecting between the coupling flow path and the hollow portion, a locking protrusion 11 protruding inward in the middle of the hollow portion, Way valve 8 that is movably inserted between the two-way valve 8.

The diameter of the communication hole is relatively smaller than the diameter of the one way valve 8 and the diameter of the hollow portion is larger than the diameter of the one way valve 8 and the inner diameter of the stopping jaw 11 is larger than the diameter of the one way valve 8 So that the one-way valve 8 can move left and right between the inner end of the hollow portion and the engaging jaws 11.

Way valve 8 is operated by the difference between the intake pressure by the supercharging and the exhaust pressure by the exhaust gas recirculation. In the case where the exhaust pressure is larger than the intake pressure, Way valve 8 is moved from one end of the hollow portion to the engaging step 11 and is in close contact with the third port 10c to open the third port 10c and the exhaust gas is introduced into the intake manifold 1). ≪ / RTI >

On the other hand, when the intake pressure is greater than the exhaust pressure, the one way valve 8 moves from the engagement protrusion 11 of the hollow portion of the discharge pipe 9b to the end thereof by the pressure difference, It is possible to prevent the intake air from flowing backward in the discharge pipe 9b.

5 is a pressure curve graph for explaining extraction of an exhaust gas having an exhaust pressure higher than the intake pressure according to the present invention.

Referring to FIG. 5, as shown in the upper right pressure curve graph of FIG. 5, the exhaust pressure curves of the first and second cylinders and the second and third cylinders have different phase differences with time, and the pressure varies in the vertical direction.

As shown in the graph of the pressure curve at the lower left of the drawing, the intake pressure curve is represented by a horizontal line (dotted line), only an exhaust pressure curve with a higher pressure than the horizontal line is displayed, The pressure curve was removed.

This indicates that the exhaust gas is recirculated by extracting only the exhaust pressure higher than the intake pressure by using the pulse switching valve 7 and the one-way valve 8 of the present invention.

As shown in the graph of the pressure curve at the lower right of the drawing, the graphs of the exhaust gas pressure curves of 1, 3 cylinder and 2, 3 cylinder are shown as shaded exhaust gas pressure lower than the intake air pressure, It is indicated that the backflow phenomenon may occur.

Here, the pulse switching valve 7 and the one-way valve 8 are provided on the EGR line for connecting the intake manifold 1 to the exhaust manifold 6 and recirculating the exhaust gas. In the above description, The pulse switch valve 7 and the one way valve 8 may be installed separately in the pump 9 and the pulse switch valve 7 and the one way valve 8 may be provided separately from each other .

For example, the pulse switching valve 7 is directly connected to the first and second exhaust manifolds 4 and 5, the one-way valve 8 is connected to the intake manifold 1, and the pulse switching valve Way valve 8 and the EGR cooler 13 and the EGR valve 14 can be provided between the two-way valve 7 and the one-

It is a matter of course that the functions of the pulse switching valve 7 and the one way valve 8 are the same.

When the number of cylinders is six or less, only one pulse switching valve 7 can be used. However, when the number of cylinders is eight, two pulse switching valves 7 may be used.

In addition, when there are a plurality of recirculation lines 12, it is possible to recycle the many one way valves to the intake system of the engine 2.

Therefore, according to the present invention, the pulse switching valve 7 and the one-way valve 8 are applied on the recirculation line 12 to extract the exhaust pressure higher than the intake pressure in the exhaust manifold 6, The EGR gas can be recirculated irrespective of the increase in the intake air pressure due to supercharging.

In addition, it is possible to prevent the reverse flow of the exhaust gas due to the intake air compression of the turbocharger 16, thereby suppressing the knock, reducing the knock, and reducing the pumping loss.

1: Intake manifold (intake system)
2: engine
3: Cylinder
4: First exhaust manifold
5: Second exhaust manifold
6: Exhaust manifold (Exhaust system)
7: Pulse switching valve
8: One Way Valve
9: Valve body
9a: inlet pipe
9b: discharge pipe
10a: first port
10b: second port
10c: third port
11: hanging jaw
12: recirculation line
13: EGR cooler
14: EGR valve
15: Exhaust pipe (muffler)
16: supercharger
17: Intercooler

Claims (8)

1. An exhaust gas recirculation apparatus for recycling a part of an exhaust gas to an engine (2) through an intake system,
An engine (2) having a plurality of cylinders (3);
An exhaust manifold 6 for bifurcating the exhaust gas discharged from the cylinder 3;
A pulse switching valve (7) connected to the exhaust manifold (6) for selectively opening and closing a flow path of exhaust gas branched in two directions; And
Way valve (8) installed in an exhaust gas recirculation line (12) between the exhaust manifold (6) and the intake system of the engine (2) to prevent reverse flow of recirculated exhaust gas;
And,
Each of the cylinders 3 is divided into two groups by an exhaust manifold 6. When the number of cylinders 3 is an even number, each group of the exhaust manifolds 6 has a symmetrical structure, The number of the exhaust manifolds 6 of each group is asymmetric or the exhaust gas of any one of the cylinders 3 of the group of cylinders 3 having a larger number of cylinders is directly discharged to the exhaust pipe 15 without recirculation And the exhaust gas recirculation device is capable of discharging the exhaust gas through the exhaust gas recirculation device.
The method according to claim 1,
The exhaust manifold 6 is constituted by first and second exhaust manifolds 4 and 5 for connecting the cylinders 3 in a branch structure and is connected to the first exhaust manifold 4 on the basis of the ignition sequence, Wherein the cylinder (3) of the second exhaust manifold (5) and the cylinder (3) of the second exhaust manifold (5) are configured to be alternately ignited.
delete The method according to claim 1,
The pulse switching valve 7 and the one way valve 8 are installed inside a valve body 9 composed of a T-shaped body. The valve body 9 is formed separately on both sides of the valve body 9, A first port 10a and a second port 10b for introducing exhaust gas into the first port 10a and the second port 10b and a third port 10b formed in a direction opposite to the first port 10a and the second port 10b, Way valve 10c and the first port 10a and the second port 10b are selectively opened and closed by the operation of the pulse switching valve 7. The third port 10c is connected to the one- So that the exhaust gas can be discharged only in one direction by the exhaust gas recirculation device.
The method according to claim 1,
Wherein the pulse switching valve (7) and the one-way valve (8) are separately provided separately from each other.
The method according to claim 1,
Wherein the pulse switching valve (7) is installed in a plurality of separate states.
The method according to claim 1,
Wherein the one-way valve (8) is installed on each of a plurality of exhaust gas recirculation lines (12).
The method according to claim 1,
Wherein the pulse switching valve (7) and the one-way valve (8) are formed in a ball shape.

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