JPH09151809A - Exhaust gas recirculating device and method for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mix intake air with E.G.R. gas in its early stages and uniformly distribute them in order to reduce NOx gas generated at the time of combustion of an engine. SOLUTION: In an exhaust gas recirculating(E.G.R.) device, an E.G.R. passage 8, through which a part of exhaust gas 7 is recirculated into an intake air manifold 5, and an E.G.R. valve 10 are prepared. In addition, an E.G.R. gas returning port 12 is arranged, which is communicated with the E.G.R. passage 8 through which the exhaust gas 7 is gushed into the intake air minifold 5, at the downstream of the E.G.R. valve 10. Further, a variable E.G.R.-gas-passage throttle valve 11 is prepared, in which the area of the passage can be varied, between the E.G.R. valve 10 and the E.G.R. gas returning port 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine exhaust gas recirculation method and apparatus.

[0002]

2. Description of the Related Art Conventionally, in an automobile engine, in order to purify exhaust gas, part of the exhaust gas is returned to an intake manifold to reduce nitrogen oxides (hereinafter referred to as NOx) in the exhaust gas. Some are provided with a gas recirculation device (hereinafter referred to as an EGR device). In this EGR device, exhaust gas, which is an inert gas generated during combustion of the engine, is returned into the intake manifold to reduce the combustion temperature in each cylinder and reduce the generation of NOx generated at high temperatures. . In this device, the exhaust gas (hereinafter referred to as EGR gas) returned to the intake manifold is used to make the EGR gas amount proportional to the intake air amount of the engine, that is, the intake air amount as one means for reducing NOx. It is necessary to keep the ratio of exhaust gas recirculation amount to
In order to improve the fuel consumption, it is possible to change the ratio according to the operating conditions of the engine or increase or decrease the EGR gas amount itself. Engine E considering these
Regarding the GR device, Japanese Patent Laid-Open No. 59-229044 has been proposed. Japanese Unexamined Patent Publication No. 59-229044 discloses a negative pressure responsive recirculation amount control valve provided in an exhaust gas recirculation passage branching from an exhaust passage of an internal combustion engine to the intake passage, and a recirculation amount control valve operating negative valve. A negative pressure control valve that controls the pressure to increase and decrease substantially in proportion to the intake air amount of the engine; and a first control valve that can change the control pressure of the negative pressure control valve under specific operating conditions to change the exhaust gas recirculation rate. The second control valve that changes the control pressure of the negative pressure control valve under a specific condition to change the exhaust gas recirculation amount with different characteristics from the first control valve.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
JP-A-59-229044 discloses that the control pressure of the negative pressure control valve is changed by the first control valve to change the exhaust gas recirculation rate.
The control valve changes the amount of exhaust gas recirculation to suppress the generation of nitrogen oxides and reduce fuel consumption. Here, in order to further suppress the generation of nitrogen oxides, controlling the flow velocity ratio between the intake air and the EGR gas can be mentioned. By forming the flow velocity ratio of both fluids, early mixing of both fluids can be promoted and E to each cylinder can be increased.
The GR gas can be evenly distributed, and the generation of nitrogen oxides can be effectively reduced.

An object of the present invention is to efficiently reduce the combustion temperature of the engine and to reduce NOx generated in a large amount during high temperature combustion.

[0005]

A first feature of the present invention for achieving the above object is a bypass for recirculating a part of exhaust gas (EGR gas) from an engine exhaust manifold into an intake manifold. A pipe is provided, an EGR valve for controlling the amount of EGR gas is provided in the bypass pipe, and at least an EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold is provided downstream of the EGR valve. With one exhaust gas recirculation device, the EGR gas flow rate to be recirculated into the intake manifold is controlled via the EGR valve, and then the EGR valve and the EG
It is possible to obtain a desired EGR gas flow velocity through a flow velocity control means arranged between the R gas return ports.

A second feature of the present invention for achieving the above object is the exhaust gas recirculation device for an engine according to the first feature of the present invention, wherein the flow velocity control means is arranged in the bypass pipe. The control is performed by providing at least one throttle valve whose passage cross-sectional area is variable between the EGR valve and the EGR gas return port.

A third feature of the present invention for achieving the above object is the exhaust gas recirculation system for an engine according to the first feature of the present invention, in which the EG supplied from the EGR gas return port is supplied.
The EGR gas flow velocity is controlled so that the R gas flows in the vicinity of the center of the vertical cross section with respect to the intake flow in the intake manifold downstream of the EGR gas return port.

A fourth aspect of the present invention for achieving the above object is the exhaust gas recirculation system for an engine according to the first aspect of the present invention, wherein the EGR gas return port is connected to the intake air flow in the intake manifold. It is located near the center of the vertical section.

A fifth feature of the present invention for achieving the above object is to dispose a bypass pipe for recirculating a part of the exhaust gas (EGR gas) from the exhaust manifold of the engine into the intake manifold, An EGR valve for controlling the amount of EGR gas is provided in the bypass pipe, and at least one EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold is provided downstream of the EGR valve. In the exhaust gas recirculation device, E is provided between the EGR valve disposed in the bypass pipe and the EGR gas return port.
A flow velocity control means for controlling the flow rate of the GR gas is provided, and the flow velocity control means is provided with a plurality of throttle valves each having a continuously variable passage cross-sectional area so that the throttle valves can be individually controlled. .

A sixth feature of the present invention for achieving the above object is an exhaust gas recirculation device for an engine according to the fifth feature of the present invention, wherein the E gas ejected from the EGR gas return port is ejected.
The GR gas is jetted and supplied into the intake manifold at a predetermined angle with respect to the intake air flow flowing in the intake manifold, and the EGR gases are arranged so as to collide with each other in the intake manifold. .

A seventh aspect of the present invention for achieving the above object is an exhaust gas recirculation apparatus for an engine according to any one of the first to sixth aspects of the present invention, wherein the flow velocity is intermittently varied by using the flow velocity control means. Is to let.

An eighth feature of the present invention for achieving the above object is to dispose a bypass pipe for recirculating a part of the exhaust gas (EGR gas) from the engine exhaust manifold into the intake manifold, An EGR valve for controlling the amount of EGR gas is provided in the bypass pipe, and at least one EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold is provided downstream of the EGR valve. In the exhaust gas recirculation device, the EGR gas is supplied when the pressure pulsation amplitude waveform in the intake manifold is convex upward and downward at the EGR gas return port.

A ninth feature of the present invention for achieving the above object is to dispose a bypass pipe for recirculating a part of the exhaust gas (EGR gas) from the exhaust manifold of the engine into the intake manifold, A pulse-type EGR valve for controlling the amount of EGR gas is arranged in the bypass pipe, and at least one EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold is provided downstream of the pulse-type EGR valve. The arranged exhaust gas recirculation device controls the pulse type EGR valve, and supplies EGR gas when the pressure pulsation waveform in the intake manifold is convex upward or downward at the EGR gas return port. is there.

A tenth aspect of the present invention for achieving the above object.
In the first to ninth aspects of the present invention, the flow velocity control means and the pulse-type EGR valve include an air flow sensor output signal and a crank angle sensor output signal for measuring the amount of intake air passing through the intake manifold, The control is performed using either the cylinder pressure sensor output signal, the intake manifold pressure sensor output signal, or the like.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. FIG. 1 shows the exhaust gas recirculation (hereinafter,
It is an explanatory view of an engine 1 using a device (referred to as EGR) (when one EGR gas return port 12 is provided) (EG
Method 1 for returning R gas). The white arrows in FIG. 1 indicate the flow of the intake air 2 used for combustion in the cylinder 13 and the flow velocity U of the intake air 2. The measurement of the intake air 2 is measured by the air flow sensor 3. The amount of intake air 2 is adjusted by throttle valve 4 arranged downstream of air flow sensor 3.
It is implemented by opening and closing. After that, the intake air 2 is supplied to the inside of the cylinder 13 through the intake manifold 5, used for combustion, and then passes through the exhaust manifold 6 to be exhausted. Here, the engine 1 using the EGR device shown in FIG.
Then, a part of the exhaust gas 7 flows into the EGR passage 8 (bypass pipe) provided downstream of the exhaust manifold 6 as the EGR gas 9 as shown by a black arrow. Inflowed E
The GR gas 9 is the EGR valve 10 provided in the EGR passage 8.
(In this embodiment, as shown in the drawing, a negative pressure control type EGR
A valve is shown, but other types of EGR valves are also applicable) to control a predetermined flow rate. After that, the EGR gas 9 is
An EG arranged downstream of the EGR valve 10 in the EGR passage 8.
It passes through the R gas variable throttle valve 11. This allows the EGR passage 8 sectional area to be continuously and arbitrarily adjusted. Variable throttle valve 11
Is controlled by the control unit 15 using an intake air quantity signal that passes through the intake manifold 5 (for example, an air flow sensor output signal). Where EGR
When the gas 9 passes through the variable throttle valve 11, the EG
The jet flow velocity u from the R gas return port 12 can be adjusted. Therefore, it is possible to form the optimum flow rate ratio u / U for the early mixing of the intake air 2 and the EGR gas 9 described above. Therefore, the intake air 2 and the EGR gas 9 are early mixed and uniformly supplied into each cylinder 13, and the combustion temperature in the cylinder 13 can be effectively lowered, and nitrogen oxides (NOx) which are harmful substances generated at the time of high temperature combustion. ) Can be reduced.

FIG. 2 is an explanatory view of an engine using the EGR device of the present invention (EGR gas returning method second plan). The difference from FIG. 1 lies in the shapes of the intake and exhaust manifolds 5 and 6. As shown in the figure, the intake / exhaust manifold 5, 5 is shaped so that the direction of the intake / exhaust air 2, 7 flowing in the intake / exhaust manifold 5, 6 changes substantially at a right angle until it reaches the inside of the cylinder and is discharged from the cylinder. 7 Also, E
The configurations of the GR valve 10 and the EGR gas variable throttle valve 11 and the control method of the variable throttle valve 11 are the same as those described with reference to FIG. The feature of the present invention here is that the optimum flow rate u / for the early mixing of the intake air 2 and the EGR gas 9 is the same as described in FIG.
To form U. Further, when the approach distance sufficient to mix the intake air 2 and the EGR gas 9 cannot be obtained, the opening / closing control of the EGR gas variable throttle valve 11 causes the EG
By changing the R gas flow velocity u and changing the mainstream flow of the EGR gas 9 from the EGR gas return port 12 to an arbitrary position in a vertical cross section with respect to the flow of the intake air 2 flowing in the intake manifold 5, the EGR gas 9 to EGR gas return port 1
The cylinder 13 on the front side and the cylinder 14 on the rear side are distributed almost uniformly. That is, the cylinder 13
When it is desired to supply the EGR gas 9 to the side, the EGR gas variable throttle valve 11 is throttled to reduce the cross-sectional area of the EGR gas passage, the EGR gas flow velocity is increased to facilitate the flow to the cylinder 13 side, and the EGR gas to the cylinder 14 side. When it is desired to supply 9, the EGR gas variable throttle valve 11 can be expanded to increase the EGR gas passage cross-sectional area, reduce the EGR gas flow velocity, and facilitate the flow to the cylinder 14 side. Therefore, the uniform distribution of the EGR gas 9 to the cylinders 13 and 14 can be controlled.

FIGS. 3 to 5 are explanatory views of the first, second, and third alternatives of the EGR gas variable throttle valve 11 of the present invention, which is a detailed view of the portion A in FIGS. 1 and 2. Exhaust gas 7 in FIGS. 3 to 5
The EGR gas 9 that is a part of the EGR passage 8 when passing through the EGR passage 8 provided downstream of the exhaust manifold 6
After being adjusted to a predetermined flow rate by the EGR valve 10 provided in the EGR gas, the EGR gas 9 flows at the flow rate u ′ on the upstream side of the EGR gas variable throttle valve 11. Here, in the case of FIG. 3, the EGR gas 9
Is provided with an EGR gas variable throttle valve 11 that makes it possible to control the passage cross-sectional area (filled portion in the figure) a such as a camera shutter valve to an arbitrary cross-sectional area.
The flow velocity u of the EGR gas 9 passing through the EGR gas variable throttle valve 11 can be controlled. In the case of FIG. 4, the EGR gas 9 is provided with an EGR gas variable throttle valve 11 capable of controlling the passage cross-sectional area (filled portion in the figure) a such as the throttle valve 4 (butterfly valve) to an arbitrary EGR gas variable throttle valve 11.
The flow velocity u of the EGR gas 9 passing through the gas variable throttle valve 11 can be controlled. In the case of FIG. 5, the EGR gas 9 is provided with an EGR gas variable throttle valve 11 that makes it possible to control the passage cross-sectional area (filled portion in the figure) a such as a slide valve to an arbitrary cross-sectional area. The flow velocity u of the EGR gas 9 passing through the variable throttle valve 11 can be controlled. Therefore, the EGR gas 9 flow rate and the flow rate can be sufficiently controlled with respect to the intake air 2 amount and the flow rate measured by the air flow sensor 3 and controlled by the throttle valve 4.
It is possible to form an optimum flow rate ratio that allows early mixing and uniform distribution of the intake air 2 and the EGR gas 9. Each of these valves has its own characteristics. If you want to reduce the passage resistance of the throttle valve, use the shutter valve and slide valve type variable throttle valve 11 shown in FIGS. 3 and 5, and consider productivity, durability, etc. If it says, the butterfly valve type variable throttle valve 11 of FIG. 4 will be used, and if it says in terms of structure, the butterfly valve and slide valve type variable throttle valve 11 shown in FIGS. 4 and 5 will be used. Further, in the engine of the type as shown in FIG. 1, the EGR gas 9 ejected from the EGR gas return port 12
Is capable of forming a relatively flat jet flow and promoting early mixing with the intake air 2, the butterfly valve shown in FIGS. 4 and 5,
A slide valve type variable throttle valve 11 is preferable. In the engine of the type shown in FIG. 2, the shutter valve type variable throttle valve 11 shown in FIG. 3 is preferable because it can form an arbitrary EGR gas mainstream flow in a cross section perpendicular to the intake air flow.

FIG. 6 is an explanatory view of the EGR gas returning section of the present invention (EGR gas returning method third plan). In the present invention, the control relating to the flow rate and the flow velocity of the intake air 2 and the EGR gas 9 is substantially the same as that described in FIG. 1 and FIG. The difference from the EGR gas return section in FIGS. 1 and 2 lies in the configuration of the EGR gas return port 12.
That is, the EGR gas return port 12 is connected to the intake manifold 5
The EGR gas 9 is disposed near the center of the cross section perpendicular to the flow of the intake air 2 flowing therein, and supplies the EGR gas 9 near the center of the intake air 2. As a result, an optimum mixing flow velocity ratio can be formed according to the flow velocity of the intake air 2, and early mixing is promoted.
GR gas can be uniformly supplied to each cylinder.

FIG. 7 shows an exhaust gas recirculation system (E according to the present invention.
It is an explanatory view of engine 1 using a case where a plurality of GR gas return ports 12 are arranged. The difference from the above-described explanatory view of the engine 1 using the exhaust gas recirculation device shown in FIGS. 1 and 2 is that a plurality of EGR gas return ports 12 are passed along the flow of the intake air 2 passing through the intake manifold 5. It has been arranged. Here, the EGR gas variable throttle valve 1 for controlling the flow velocity of each EGR gas 9 ejected from the EGR gas return port 12
1 corresponds to each EGR gas return port 12 and is characterized in that each EGR gas variable throttle valve 11 can be individually controlled. As a result, as shown in FIG. 8 (FIG. 7, enlarged schematic view of part A), the flow lines of the EGR gas 9 ejected from the EGR gas return ports 12 flow in the flow of the intake air 2 without substantially overlapping. . Therefore, the flow distribution of the EGR gas 9 can be widely formed in the intake manifold 5.
Even if the distance from the gas return port 12 to each cylinder 13 (the mixing distance between the intake air 2 and the EGR gas 9) is short, early mixing can be promoted. Further, when the engine of the type shown in FIG. 2 is used, it is possible to promote the uniform distribution of the EGR gas to each cylinder in the same manner as described in FIG. Therefore, early mixing of the intake air 2 and the EGR gas 9 and uniform distribution among the cylinders 13 are achieved, and reduction of NOx which is an air pollutant can be promoted.

FIG. 9 shows the fifth EGR gas returning method of the present invention.
It is explanatory drawing of a plan. Intake air 2, EGR gas 9 flow rate,
The control relating to the flow velocity is the same as that described in FIG. 1, FIG. 2, FIG. 6 and FIG. EG in FIGS. 1, 2, 6 and 7.
The difference from the R gas return method explanatory diagram is that the EGR gas return port 1
There is a difference in the configuration of 2. That is, the EGR gas return port 1
In the cross section perpendicular to the flow of the intake air 2 flowing in the intake manifold 5, a plurality of (two in FIG. 9) are arranged,
The EGR gas return port 12 is disposed so as to face each other, and the EGR gas return port 12 is disposed so that the ejected EGR gas 9 collides with it. As a result, it becomes possible to form the main flow of the EGR gas 9 at an arbitrary position within the same cross section perpendicular to the flow of the intake air 2 in the intake manifold 5. Therefore, early mixing depending on the flow velocity of the intake air 2,
An EGR gas flow rate that allows uniform distribution can be formed, and the EGR gas 9 can be uniformly supplied to each cylinder 13.

FIG. 10 is an explanatory view of the sixth EGR gas returning method of the present invention. The control regarding the flow rate and flow velocity of the intake air 2 and the EGR gas 9 is the same as that described in FIGS. The difference from the explanatory diagrams of the EGR gas returning method in FIGS. 1, 2, 6 and 7 lies in the configuration of the EGR gas return port 12. That is, a plurality (two in FIG. 10) of EGR gas return ports 12 are provided, and further, the EGR gas 9 ejected from the EGR gas return ports 12 is added to the intake air 2 flowing in the intake manifold 5. On the other hand, the EGR gas 9 is jetted and collided at a predetermined angle θ with respect to the flow of the intake air 2 in the intake manifold 5 by being injected at a predetermined angle θ. As a result, the EGR gas 9 can be formed into a main flow of the EGR gas at an arbitrary position with respect to the flow of the intake air 2. Therefore, an EGR gas flow rate capable of early mixing and uniform distribution can be formed according to the flow rate of the intake air 2, and the EGR gas 9 can be uniformly supplied to each cylinder 13.

11 and 12 show the pressure and flow velocity of the intake air 2 flowing in the intake manifold 5 of the engine according to the present invention, which is arranged by time. As shown in FIG. 11, the pressure in the intake manifold 5 is pulsating as shown by the solid line (without EGR gas flow rate control). As shown in FIG. 12, the intake air 2 is provided at the upper convex portion (A, B, C, D in FIG. 11) and the lower convex portion (a, b, c, d in FIG. 11) of this pulsation waveform. The flow velocity of is zero or low (Fig. 12
Medium A, B, C, D and a, b, c, d), the EGR gas variable throttle valve 11 is intermittently controlled, and EGR is controlled in the vicinity thereof.
By supplying the gas 9, a space in which the EGR gas 9 is uniformly filled is formed in a vertical cross section with respect to the flow of the intake air 2, and it is possible to uniformly distribute the EGR gas 9 to each cylinder. Also, EG
The mixing of both fluids is also promoted because the R gas 9 is intermittently injected and supplied. Further, as shown in FIG. 11, the EGR gas 9 has a portion where the pressure pulsation waveform is convex upward (A, B, C,
In D), when the EGR gas 9 is supplied (flow rate control), when the EGR gas 9 is not supplied (flow rate control) (see FIG. 1).
1), the amplitude of pressure pulsation waveform increases (Fig. 1).
The effect of improving the efficiency of the intake air taken into the cylinder 13 is also obtained.

FIG. 13 is an explanatory diagram of an engine using the exhaust gas recirculation system (without the EGR gas variable throttle valve 11) of the present invention. In the present embodiment, E is provided downstream of the EGR valve 10.
Intake air 2 and EGR without using the GR gas variable throttle valve 11
This is an example of promoting the early mixing and uniform distribution of the gas 9.
That is, using the EGR valve (pulse type) 10, a part of the exhaust gas 7 flowing in the exhaust manifold 6 is changed to the EGR gas 9
As a result, when the EGR valve (pulse type) 10 is controlled to be intermittently supplied at the convex portion on the pressure pulsation waveform of the intake air 2 when returning to the intake manifold 5, as shown in FIG.
There is the same effect as described in FIG. 12, and early mixing and uniform distribution of both fluids of the intake air 2 and the EGR gas 9 are promoted. In addition, the intake efficiency of the engine can be improved. Furthermore, EG
Since the R gas variable throttle valve 11 is not used, it is possible to provide an inexpensive engine exhaust gas recirculation device.

The EGR valve 1 described in the above embodiment is also used.
0, EGR gas variable throttle valve 11 is controlled by an air flow sensor output signal for measuring the amount of intake air intake 2 or a throttle valve output signal for controlling the same, an in-cylinder pressure sensor, a crank angle sensor, and an intake manifold It is possible to use each output signal of the pressure sensor or the like.

[0025]

According to the present invention, the ratio of the flow velocity of the intake air passing through the intake manifold to the flow velocity of the EGR gas which is a part of the exhaust gas returned from the exhaust manifold to the intake manifold is arranged in the bypass pipe. A variable throttle valve is provided between the EGR valve and the EGR gas return port to control the fluid flow velocity ratio to a predetermined ratio, and the intake air pressure flowing in the intake manifold by controlling the EGR valve and throttle valve intermittently. By supplying EGR gas to the convex portion on the pulsation waveform, early mixing of both fluids and uniform distribution to each cylinder are promoted,
Since the combustion temperature in each cylinder can be efficiently reduced, there is an effect that NOx generated during combustion can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an engine using an exhaust gas recirculation device of the present invention (when one EGR gas return port is provided).

FIG. 2 is an explanatory diagram of an engine using the exhaust gas recirculation device of the present invention (when one EGR gas return port is provided).

FIG. 3 is an explanatory view of a first proposal of an EGR gas variable throttle valve of the present invention.

FIG. 4 is an explanatory view of a second alternative of the EGR gas variable throttle valve of the present invention.

FIG. 5 is an explanatory diagram of a third proposal of the EGR gas variable throttle valve of the present invention.

FIG. 6 is an explanatory view of a third plan of the EGR gas returning method of the present invention.

FIG. 7 is an explanatory diagram of an engine using the exhaust gas recirculation device of the present invention (when a plurality of EGR gas return ports are provided).

FIG. 8 is an enlarged view of part A in FIG.

FIG. 9 is an explanatory view of a fifth plan of the EGR gas returning section of the present invention.

FIG. 10 is an explanatory diagram of a sixth proposal of the EGR gas returning section of the present invention.

FIG. 11 is a characteristic diagram showing the relationship between the pressure in the intake pipe of the engine of the present invention and time.

FIG. 12 is a characteristic diagram showing the relationship between the pressure in the intake pipe of the engine of the present invention and the flow velocity.

FIG. 13 is an explanatory diagram of an engine using the exhaust gas recirculation device (without an EGR valve) of the present invention.

[Explanation of symbols]

1 ... Engine, 2 ... Intake air, 3 ... Air flow sensor,
4 ... Throttle valve, 5 ... Intake manifold, 6 ... Exhaust manifold, 7 ... Exhaust gas, 8 ... EGR passage, 9 ...
EGR gas, 10 ... EGR valve, 11 ... EGR gas variable throttle valve, 12 ... EGR gas return port, 13 ... Cylinder, 15
…control unit.

Claims (10)

[Claims] 1. An EGR valve for arranging a bypass pipe for recirculating EGR gas, which is a part of exhaust gas, from an engine exhaust manifold into an intake manifold, and controlling the amount of the EGR gas in the bypass pipe. And the above E
In an exhaust gas recirculation device having at least one EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold downstream of the GR valve, the EGR for recirculating into the intake manifold.
After controlling the gas flow rate through the EGR valve, the E
An exhaust gas recirculation device for an engine, wherein a desired EGR gas flow velocity is obtained via a flow velocity control means arranged between a GR valve and the EGR gas return port. 2. The flow velocity control means according to claim 1,
The EGR valve and the EGR disposed in the bypass pipe
An exhaust gas recirculation device for an engine, which is controlled by providing at least one throttle valve having a continuously variable passage cross-sectional area between gas return ports. 3. The EGR gas flow velocity according to claim 1, wherein the EGR gas supplied from the EGR gas return port flows downstream of the EGR gas return port in the vicinity of the center of a vertical cross section with respect to the intake air flow in the intake manifold. Exhaust gas recirculation device for the engine that controls the 4. The exhaust gas recirculation system for an engine according to claim 1, wherein the EGR gas return port is provided near the center of a vertical cross section with respect to the intake air flow in the intake manifold. 5. An EGR valve for arranging a bypass pipe for recirculating EGR gas, which is a part of exhaust gas, from an engine exhaust manifold into an intake manifold, and controlling the amount of the EGR gas in the bypass pipe. And the above E
In an exhaust gas recirculation device in which at least one EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold is provided downstream of the GR valve,
The EGR valve and the EGR disposed in the bypass pipe
A flow velocity control means for controlling the EGR gas flow velocity is arranged between the gas return ports, and a plurality of throttle valves capable of continuously varying the passage sectional area of the flow velocity control means are arranged, and the throttle valves are individually controlled. An exhaust gas recirculation system for engines, which has been made possible. 6. The EGR gas ejected from the EGR gas return port according to claim 5, wherein the EGR gas is injected and supplied into the intake manifold at a predetermined angle with respect to an intake air flow flowing in the intake manifold. An exhaust gas recirculation device for an engine, arranged so that the EGR gases collide with each other in the intake manifold. 7. An exhaust gas recirculation system for an engine according to claim 1, 2, 3, 4, 5 or 6, wherein the flow velocity control means is used to intermittently vary the flow velocity. 8. An EGR valve for arranging a bypass pipe for recirculating EGR gas, which is a part of exhaust gas, from an engine exhaust manifold into an intake manifold, and controlling the amount of the EGR gas in the bypass pipe. And the above E
In an exhaust gas recirculation device in which at least one EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold is provided downstream of the GR valve,
An exhaust gas recirculation method for an engine, wherein EGR gas is supplied when the pressure pulsation amplitude waveform in the intake manifold is convex upward and downward at the EGR gas return port. 9. A bypass pipe for recirculating EGR gas, which is a part of exhaust gas, from an engine exhaust manifold into the intake manifold is provided, and an E pipe is provided in the bypass pipe.
A pulse type EGR valve for controlling the amount of GR gas is provided, and at least one EGR gas return port communicating with the bypass pipe for ejecting the exhaust gas into the intake manifold is provided downstream of the pulse type EGR valve. In the exhaust gas recirculation device, the pulse type EGR valve is controlled to control the EGR
An exhaust gas recirculation device for an engine, wherein EGR gas is supplied when the pressure pulsation waveform in the intake manifold is convex upward and downward at the gas return port. 10. The method of claim 1, 2, 3, 4, 5, 6, 7, 8
Or 9, the flow velocity control means, the pulse type E
The GR valve is controlled using any one of an air flow sensor output signal for measuring the amount of intake air passing through the intake manifold, a crank angle sensor output signal, a cylinder pressure sensor output signal, an intake manifold pressure sensor output signal, and the like. Exhaust gas recirculation system for engines.