JP3536689B2 - Engine exhaust gas recirculation system - Google Patents

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 device (EGR device) for improving fuel efficiency or exhaust performance by recirculating exhaust gas.

[0002]

2. Description of the Related Art In recent years, during normal operation requiring no output, a part of exhaust gas is supplied to an intake system in order to reduce CO ₂ or NOx emission by improving fuel efficiency due to increasing interest in the environment. Various return exhaust gas recirculation systems (EGR systems) have been proposed.

As a conventional exhaust gas recirculation device for an engine, for example, an example shown in FIG. 33 (Japanese Utility Model Laid-Open No. 3-114563), an example shown in FIG.
An example shown in FIG. 35 (Japanese Patent Application Laid-Open No. 8-218949) is known.

In FIG. 33, the EGR gas from the gas introduction passage 1 is introduced into the intake pipe 2 through two horizontally opposed openings 4 through the gas guide grooves 3 provided around the intake pipe 2. Then, fresh air and EGR gas are mixed. In FIG. 34, an annular passage 6 into which the EGR gas is introduced is formed on the outer periphery of the intake pipe 5, and the EGR gas is supplied to the intake pipe 5 through a plurality of holes 7 connecting the wall of the intake pipe 5 and the annular path 6. The fresh air and the EGR gas are mixed by being introduced into the inside. These are all aimed at reducing the variation in the exhaust gas recirculation rate between the cylinders.

In FIG. 35, a second surge tank 12 is provided in the intake passage 10 downstream of the first surge tank 11, and an EGR gas introduction section 13 is arranged in the second surge tank 12. . By introducing the EGR gas into the second surge tank 13 at a position distant from the throttle valve 14 as described above, a deterioration component (deposit) of the exhaust gas is prevented from adhering to the throttle valve 14.

[0006]

However, in these conventional exhaust gas recirculation devices, EGR to the intake pipe is not provided.
It cannot be said that the gas introduction part is at the optimum position and direction.

For example, as shown in FIG. 34, only EGR gas is introduced from a hole 7 provided in the wall of the intake pipe 5, or FIG.
The introduction of the EGR gas only from the opening 4 opposed in the horizontal direction as in 3 does not make it possible to mix the EGR gas and fresh air satisfactorily. In FIG. 34, the flow state of the fresh air by the throttle valve greatly affects the mixing of the EGR gas and the fresh air and the adhesion of the deposit to the throttle valve. In the case where the EGR gas is introduced into the second surge tank 13 as shown in FIG. 35, it is difficult to uniformly distribute the EGR gas from the surge tank 13 to each cylinder.

For this reason, when a large amount of EGR is performed, the mixing of the EGR gas and fresh air becomes insufficient, and as a result, the EGR rate varies among the cylinders, deteriorating the stability of the engine and reducing the emission. This leads to an increase in fuel efficiency. Except for those shown in FIG. 35, there is a concern that the control of the intake air amount and the like may be deteriorated due to the formation of a deposit on the throttle valve.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art, and has as its object to improve the variation of the exhaust gas recirculation rate between the cylinders and prevent the exhaust gas from being deposited on the throttle valve. Is to provide.

[0010]

According to a first aspect of the present invention, there is provided an intake system provided with a throttle valve upstream of an intake pipe provided with a branch pipe connected to each cylinder and a collector, and an external recirculation passage is provided from the exhaust system. In an exhaust gas recirculation system for an engine that introduces EGR gas into the intake pipe behind the throttle valve of the intake system and upstream of the collector via the intake system, the throttle valve when the EGR gas introduction port to the intake pipe of the external recirculation path is closed is closed. arranged than the circumference tangential direction of the intake pipe section at a position along the opposite banks of the rear free end, and against the axial direction of the intake pipe straight
Turn the direction of the intersecting cross section .

[0011] In a second aspect based on the first aspect, the EG
The R gas inlet is located at a position behind the forward free end of the throttle valve and at a position behind the free backward end of the throttle valve.

According to a third aspect of the present invention, in the second aspect, the EGR gas inlet on the free front end side and the EGR gas inlet on the free rear end side of the throttle valve are opened in a cross-flow manner.

[0014] In a fourth aspect based on the second aspect, the cross-sectional area of the EGR gas inlet port on the free front end side of the throttle valve is made larger than the cross-sectional area of the EGR gas inlet port on the rear free end side.

According to a fifth aspect of the present invention, in the second aspect, the EGR gas inlet at the rearward free end side of the throttle valve is connected to the EGR gas inlet.
Auxiliary air is introduced instead of GR gas.

In a sixth aspect based on the first aspect, the EG
A guide case for projecting the R gas inlet into the intake pipe is provided.

According to a seventh aspect, in the first aspect, the EG is provided.
The cross section of the R gas inlet is formed in an elliptical shape.

According to an eighth aspect based on the first aspect, the EG
The opening area of the R gas inlet depends on the maximum speed of fresh air passing through the throttle valve, the distance from the throttle valve shaft center to the EGR gas inlet, and the EGR gas blowing speed corrected by the opening shape of the EGR gas inlet. To set.

In a ninth aspect based on the second aspect , the intake pipe including the throttle chamber is provided with a throttle valve.
If there is a bend with the free front end inside,
EG on the free end side of the throttle valve that leans forward according to the angle of inclination
The position of the R gas inlet is located downstream, and the EGR at the free end
Introduce EGR gas at the free end side of the gas inlet at its free forward end
Correct downstream to a greater proportion than the mouth . Tenth invention
Includes the throttle chamber according to the second invention.
Make the intake pipe with the rear free end of the throttle valve
If you have a bend, the slot
The position of the EGR gas inlet on the free end of the valve
On the downstream side, the position of the EGR gas
Up at a smaller ratio than the EGR gas inlet on the free end side
Correct to the downstream side.

[0019]

According to the first aspect of the invention, the main flow of fresh air and the EGR gas passing through the free end side of the throttle valve are mixed by a spiral flow (spiral flow) in a circumferentially downstream direction of the intake pipe. Thus, mixing is promoted, and even under a large amount of EGR rate, variation in EGR rate between the cylinders can be sufficiently reduced, and fuel efficiency and exhaust performance can be improved. Further, the EGR gas does not enter the reverse flow area downstream of the throttle valve, so that formation of a deposit on the throttle valve can be prevented. Further, the EGR gas inlet can be easily processed.

According to the second invention, the mainstream of fresh air and EGR
Since the EGR gas is introduced from two positions where the mixing with the gas and the effect of preventing the inflow of the EGR gas into the reverse flow region are obtained, a larger amount of the EGR gas is newly added while preventing the deposit from being formed on the throttle valve. It can be mixed well with air.

According to the third aspect of the present invention, the EGR gas immediately after the introduction does not collide with each other and the EGR gas does not diffuse toward the center of the intake pipe, and the EGR gas does not enter the reverse flow area. Can be sufficiently prevented.

According to the fourth aspect of the present invention, since the area of the gas inlet in the larger main flow area is increased, the EGR gas does not enter the reverse flow area, and deposit formation on the throttle valve can be sufficiently prevented. .

According to the fifth aspect, the spiral flow for mixing the fresh air and the EGR gas is strengthened and the mixing thereof is further promoted. Therefore, even with a large amount of the EGR rate, the EGR rate between the cylinders can be improved. Can be sufficiently reduced. In addition, since the auxiliary air is introduced from the gas inlet on the rearward free end side of the throttle valve, the EGR gas does not enter the reverse flow area from the narrow main flow area, and deposit formation on the throttle valve can be sufficiently prevented.

According to the sixth aspect, the main flow passing through the free end side of the throttle valve in the guide case is guided to the spiral flow in the circumferential downstream direction of the intake pipe, and therefore, the mixing of fresh air and EGR gas is enhanced. Therefore, the mixing is further promoted, and the variation in the EGR rate between the cylinders can be sufficiently reduced even under a large amount of the EGR rate. In addition, since the flow of the flow toward the center of the intake pipe due to the collision of the fresh air and the EGR gas is eliminated and the EGR gas does not enter the reverse flow region, formation of a deposit on the throttle valve can be sufficiently prevented.

According to the seventh aspect, the gas inlet can be arranged near the throttle valve where the reverse flow area in the intake pipe is large and the main flow area on the free end side of the throttle valve is narrow. The spiral flow of the air is extended and the mixing time of fresh air and EGR gas can be extended, so that the mixing is promoted, and even under a large amount of EGR rate,
Variations in the EGR rate between the cylinders can be sufficiently reduced. Further, deposit formation on the throttle valve can be sufficiently prevented.

According to the eighth aspect of the present invention, the EGR gas is prevented from stalling due to the collision between the fresh air main stream and the EGR gas, and the spiral flow can be stably secured. Mixing is promoted and large amounts of E
Even under the GR rate, it is possible to sufficiently reduce the variation in the EGR rate between the cylinders. Further, the flow of the EGR gas in the direction of the center of the intake pipe due to the collision is prevented from being bent, and the EGR gas flows in the reverse flow region.
Since gas does not enter, deposit formation on the throttle valve can be sufficiently prevented.

According to the ninth and tenth aspects of the present invention, the gas inlet can be arranged in the intake pipe having a bent portion in accordance with the shape of the reverse flow area in the intake pipe. Similarly, the mixture of fresh air and EGR gas is promoted, and a large amount of E
Even under the GR rate, it is possible to sufficiently reduce the variation in the EGR rate between the cylinders. Further, the EGR gas does not enter the reverse flow area, and the formation of a deposit on the throttle valve can be sufficiently prevented.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a first embodiment, in which 20 is an engine, 21 is an intake manifold, and 22 is an exhaust manifold.

The intake manifold 21 includes an intake pipe 23,
A throttle 24 having a predetermined volume following the intake pipe 23 and a branch pipe 25 connected from the collector 24 to each cylinder of the engine is connected to a throttle body 26 connected upstream of the intake pipe 23. You.

The exhaust manifold 22 includes a branch pipe 28 connected to each cylinder of the engine, and an exhaust pipe 30 where the branch pipes 28 gather.

An EGR passage (exhaust recirculation passage) for recirculating a part of the engine exhaust gas from the exhaust pipe 30 to the intake system.
A branch 31 is formed, and the EGR passage 31 is branched into two passage portions 32 and 33 from the middle, and is connected to the intake pipe 23 behind the throttle valve 27 of the intake system and upstream of the collector 24.

The gas inlet 34 of one of the passages 32 has a rearward free end 2 of the throttle valve 27 in the closed state.
7a, the gas inlet 35 of the other passage portion 33 is connected to the throttle valve 2 in the closed state.
7 is opened at a position behind the forward leaning free end 27b.

In this case, as shown in FIGS. 1 to 3, the gas introduction ports 34 and 35 are provided in the circumferential tangent direction of the cross section of the intake pipe 23 and are opened in a cross-flow manner in which the inflow directions are opposed to each other. , Are formed perpendicular to the axial direction of the intake pipe 23.

The gas inlets 34 and 35 may be formed from opposite directions, respectively, or one of them may be provided.

Next, the operation will be described.

FIG. 4 shows a normal operation range and an EGR range expressed by the engine speed and the throttle opening. The region where the EGR is used in the normal operation region is a region excluding a high load region near the throttle fully open and a low load region near the idle.

FIGS. 5 and 6 show the flow downstream of the throttle valve 27 in the intake pipe 23. In contrast to the main flow passing through the opening of the throttle valve 27, a reverse flow area in which the flow circulates behind the throttle valve 27 is shown. Exists. The size of the reverse flow area depends on the throttle opening as shown in FIG. FIGS. 8 and 9 show the reverse flow forms in the high load region and the low load region.

Here, the influence of the EGR introduction position A on the physical phenomenon in the intake pipe 23 will be described with reference to FIGS.

First, as shown in FIG.
When the GR is introduced horizontally, the EGR gas is sandwiched between the main flows passing through the two free ends of the throttle valve 27 and cannot be diffused. The EGR gas is caused to flow downstream in the shortest time. The condition is bad. When EGR is horizontally introduced into the reverse flow area near the throttle valve 27 as shown in FIG. 11, the EGR gas directly hits the throttle valve 27, thereby causing a deposit to be formed.

As shown in FIG. 12, the EGR is located near the tip of the backflow area.
When the is introduced horizontally, it is easily affected by fluctuations in the engine load state due to the throttle opening, and the mixed state of EGR gas and fresh air and the prevention of deposits are both unstable. In particular, in the case of a large amount of EGR, the phenomenon becomes remarkable.

When the EGR is introduced into the intake pipe 23 from above and below as shown in FIGS. 13 and 14, the mixed state of the EGR gas and fresh air due to the influence of the backflow region, and the performance of deposit prevention are shown in FIGS. Same as horizontal introduction. In the case of FIG. 13, the EGR gas is deflected, and the mixed state with fresh air is deteriorated. In the case of FIG. 14, it is easy to change depending on the magnitude of the flow rate of the EGR.
In the case of a strong flow velocity crossing the main flow passing through the two free ends, the deposit formation becomes strong, and in the case of a weak flow velocity, the flow becomes eccentric and the mixing state with fresh air deteriorates.

FIG. 7 shows the relationship between the mixing state of EGR gas and fresh air and the formation of deposits in these backflow regions.

From the above findings, the requirements satisfying both the promotion of mixing of EGR gas and fresh air and the prevention of deposit are as follows.

No backwater basin is used.

A sufficient residence time of the EGR gas is maintained.

The air mixes with the main flow of fresh air causing the drift, that is, the entire main flow passing through both free ends of the throttle valve 27.

Therefore, in this embodiment, as shown in FIGS. 15 to 17, the EGR gas is supplied to the main flow (upper main flow, lower main flow) passing through both free ends 27a and 27b of the throttle valve 27 and the intake pipe 23. The mixing is performed by a spiral flow in the circumferential downstream direction.

That is, the throttle valve 27 when the other gas inlet 35 is also in the closed state is located at a position rearward of the rearward free end 27a of the throttle valve 27 when one of the gas inlets 34 is in the closed state. At the rear of the forward inclined free end 27b of the air intake pipe 23, the main flow velocity of the fresh air is the largest, and the reverse flow area is open at a cross-flow type in which the inflow direction is opposed to each other. Both free ends 27a, 27 of the throttle valve 27 that do not generate
At the position behind b, the fresh air and the EGR gas are merged, and a spiral flow in the circumferential downstream direction of the intake pipe 23 is formed by the fresh air and the EGR gas, and mixed.

The EGR gas introduced into the intake pipe 23 has only a velocity component in the circumferential tangential direction of the cross section of the intake pipe 23, but is pushed by the flow of fresh air after the introduction (the downstream direction of the fresh air flow). Is applied, so that a spiral flow as shown in FIG. 15 is formed.

As a result, the residence time of the EGR gas is significantly longer than that of the conventional one. In addition, due to the merging with the main stream of fresh air, the cause of the drift is eliminated, and the spiral flow downstream causes the diffusion from the outer periphery to the center of the intake pipe 23 to proceed.

Further, the EGR gas does not enter the reverse flow area downstream of the throttle valve 27, and the formation of a deposit on the throttle valve 27 is prevented.

Therefore, the mixing of the EGR gas and fresh air can be promoted, the variation in the EGR rate between the cylinders can be improved, and the prevention of deposit can be achieved.

FIGS. 18 and 19 show the moving distance (residence time) of EGR gas to the inlet of the most upstream branch pipe 25 and the EGR gas.
When the cylinder distribution ratio of the ratio is shown, the moving distance of the EGR gas in the embodiment is significantly longer due to the spiral flow, and the cylinder distribution ratio of the EGR ratio is sufficiently smaller than the conventional one.

FIG. 20 and FIG. 21 show the EGR introduction position and the state of deposit formation. As shown in FIG.
GR is connected to both free ends 27a, 27b of the throttle valve 27.
By introducing from the side (upper side, lower side), deposit formation is sufficiently prevented.

As a result, even under a large amount of EGR rate, variations in the EGR rate among the cylinders can be sufficiently reduced, and the fuel efficiency and exhaust performance can be improved. Further, it is possible to prevent the influence of the deposit formation on the control accuracy of the intake air amount.

The gas inlets 34 and 35 are connected to the intake pipe 23.
Is performed in a direction orthogonal to the axial direction of the intake pipe 23, and can be manufactured by, for example, a two-axis processing machine.

FIGS. 22 to 24 show a second embodiment in which the gas introduction ports 34 and 35 of the EGR are projected into the intake pipe 23 by the guide case 40. FIG.

In this case, the guide case 40 is fitted into a pilot hole of the gas inlet provided in the intake pipe 23, and its distal end projects to the vicinity of the center line of the intake pipe 23 orthogonal to the gas inflow direction of the guide case 40. You.

The main flow (upper main flow, lower main flow) passing through both free ends 27a and 27b of the throttle valve 27 is guided by the guide case 40 into a spiral flow in the circumferential downstream direction of the intake pipe 23.

Therefore, the mixing of the fresh air and the EGR gas can be strengthened, so that the mixing is further promoted, and the variation in the EGR rate among the cylinders can be sufficiently reduced even under a large amount of the EGR rate. Further, since the flow of the flow toward the center of the intake pipe 23 due to the collision of the fresh air and the EGR gas is eliminated, and the EGR gas does not enter the reverse flow region, formation of a deposit on the throttle valve 27 can be sufficiently prevented.

FIGS. 25 and 26 show a third embodiment, in which the cross-sectional shapes of the EGR gas inlets 45 and 46 are formed into elliptical shapes. Further, the cross-sectional area of the gas inlet 46 on the side of the forward tilt free end 27b of the throttle valve 27 is larger than the cross-sectional area of the gas inlet 45 on the side of the rearward tilt free end 27a.

In this way, the backflow area in the intake pipe 23 is large, and both free ends 27a, 27a of the throttle valve 27 are formed.
Since the gas inlets 45 and 46 can be arranged near the throttle valve 27 where the main flow area on the 7b side becomes narrower, the spiral flow to the inlet of the uppermost branch pipe 25 is extended, and fresh air and E
Since the mixing time of the GR gas can be prolonged, the mixing thereof is promoted, and the E-gas between the cylinders can be increased even under a large EGR rate.
Variation in GR rate can be sufficiently reduced. Further, the shape of the gas inlets 45 and 46 is changed according to the shape of the reverse flow area, and the area of the gas inlet 46 having the larger main flow area is increased, so that the EGR gas does not enter the reverse flow area, Deposit formation on the valve 27 can be sufficiently prevented.

FIG. 27 shows a fourth embodiment.
The EGR gas is introduced from the gas inlet port 51 on the forward free end 27b side of the throttle valve 27, and the auxiliary air is introduced from the gas inlet port 50 on the rear free end 27a side of the throttle valve 27. is there.

In this case, the passage of the gas inlet 50 is connected to the air cleaner upstream of the throttle valve 27.

In this manner, the spiral flow for mixing the fresh air and the EGR gas is strengthened, and the mixing thereof is further promoted. Therefore, even if the EGR rate is large, the EGR rate among the cylinders varies. Can be sufficiently reduced. Also,
Since the auxiliary air is introduced from the gas inlet port 50 on the free end 27a of the throttle valve 27 at the rearward free end 27a, the EGR gas does not enter the reverse flow area from the narrow main flow area, and the deposit on the throttle valve 27 is sufficiently prevented. it can.

FIG. 28 illustrates the fifth embodiment. The opening areas of the gas introduction ports 55 and 56 of the EGR are determined based on the maximum velocity of fresh air passing through the throttle valve 27 and the axis of the throttle valve 27. E corrected by the distance to the gas inlets 55 and 56 and the opening shapes of the gas inlets 55 and 56.
This is set according to the GR gas blowing speed (flow speed into the intake pipe 23).

That is, as shown in FIG. 28, the flow rate of the main stream of fresh air decreases as it goes downstream,
The opening areas of the gas introduction ports 55 and 56 are set including the opening shape so that the blowing speed of the EGR gas from the gas introduction ports 55 and 56 is always higher than the main flow velocity near 6.

As a result, a sufficient blowing speed of the EGR gas is ensured as shown in FIG. 29 to prevent the EGR gas blowing speed from stalling as shown in FIG. 30 due to the collision between the main stream of fresh air and the EGR gas. A spiral flow can be secured stably. Therefore, the mixture of fresh air and EGR gas is promoted, and even at a large EGR rate, the EGR between the cylinders is reduced.
Variation in rate can be sufficiently reduced. In addition, E
Since the flow of the GR gas in the direction of the center of the intake pipe 23 is no longer bent and the EGR gas does not enter the reverse flow area,
Deposit formation on the throttle valve 27 can be sufficiently prevented.

FIG. 31 shows a sixth embodiment.
When the intake pipe 23 including the throttle chamber (throttle body 26) has a bend with respect to the collector 24 along a plane perpendicular to the axis of the throttle valve 27, the EGR of the EGR is changed in accordance with the bend angle α. The position of the gas inlets 60 and 61 is corrected.

In this case, as shown in FIG. 31, when the intake pipe 23 has a bent portion 62 (downward bent portion) in which the forward free end 27b side of the throttle valve 27 is inward, as shown in FIG. As shown in the figure, the position of the gas introduction port 61 on the free front end 27b side of the throttle valve 27 is set to the downstream side,
The position of the gas inlet 60 on the side of the rearward tilting free end 27a is corrected to the downstream side at a larger ratio than the gas inlet 61.

The intake pipe 23 is connected to the throttle valve 27.
32 has a curved portion (upward curved portion) with the rear free end 27a side inward, the gas inlet 60 of the throttle valve 27 at the rear free end 27a side as shown in FIG. The position is corrected to the upstream side, and the position of the gas inlet 61 on the side of the forward inclined free end 27b is corrected to the upstream side at a smaller ratio than the gas inlet 60.

When the intake pipe 23 has a downwardly bent portion, the reverse flow region moves to the rearward free end 27a of the throttle valve 27, so that the gas introduction ports 60 and 61 are formed relatively downstream, and the gas introduction is performed. Move mouth 60 away from the backflow area.

When the intake pipe 23 has an upward bend, the reverse flow region moves toward the center of the intake pipe 23. In this case, the gas inlets 60 and 61 are formed relatively upstream, and the EG is formed.
Increase the moving distance of R gas.

As described above, the gas inlets 60 and 61 can be optimally arranged in the intake pipe 23 having the bent portion in accordance with the shape of the reverse flow area in the intake pipe 23. Thus, the mixture of fresh air and EGR gas is promoted, and even when the EGR rate is large, the variation in the EGR rate between the cylinders can be sufficiently reduced. In addition, of course, the EGR gas does not enter the reverse flow region, and the formation of a deposit on the throttle valve 27 can be sufficiently prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment.

FIG. 2 is a layout diagram of gas inlets according to the first embodiment.

FIG. 3 is a layout diagram of gas inlets according to the first embodiment.

FIG. 4 is a characteristic diagram showing an EGR region.

FIG. 5 is an explanatory diagram showing a flow downstream of a throttle valve.

FIG. 6 is an explanatory diagram showing a flow downstream of a throttle valve.

FIG. 7 is a characteristic diagram showing a relationship between a throttle opening and a reverse flow region.

FIG. 8 is an explanatory diagram showing a change in a reverse flow area depending on a load condition.

FIG. 9 is an explanatory diagram showing a change in a reverse flow area depending on a load condition.

FIG. 10 is an explanatory diagram showing an EGR gas introduction position and an EGR gas diffusion state.

FIG. 11 is an explanatory diagram showing an EGR gas introduction position and a diffusion state of EGR gas.

FIG. 12 is an explanatory diagram showing an EGR gas introduction position and an EGR gas diffusion state.

FIG. 13 is an explanatory diagram showing an EGR gas introduction position and an EGR gas diffusion state.

FIG. 14 is an explanatory diagram showing an EGR gas introduction position and a diffusion state of EGR gas.

FIG. 15 is an operation explanatory view.

FIG. 16 is an operation explanatory view.

FIG. 17 is an operation explanatory view.

FIG. 18 is an explanatory diagram of an improvement effect of EGR rate cylinder distribution variation.

FIG. 19 is an explanatory diagram of the effect of improving the EGR rate cylinder distribution variation.

FIG. 20 is an explanatory diagram of an improvement effect relating to reduction of deposit formation.

FIG. 21 is an explanatory diagram of an improvement effect relating to reduction of deposit formation.

FIG. 22 is a partial configuration diagram showing a second embodiment.

FIG. 23 is a layout diagram of gas inlets according to the second embodiment.

FIG. 24 is a layout view of gas inlets according to the second embodiment.

FIG. 25 is a partial configuration diagram showing a third embodiment.

FIG. 26 is a layout diagram of gas inlets according to the third embodiment.

FIG. 27 is a partial configuration diagram showing a fourth embodiment.

FIG. 28 is an explanatory diagram of the fifth embodiment.

FIG. 29 is an operation explanatory view.

FIG. 30 is an operation explanatory view.

FIG. 31 is a partial configuration diagram showing a sixth embodiment.

FIG. 32 is a characteristic diagram showing an EGR introduction position when the intake pipe is bent.

FIG. 33 is a partial cross-sectional view of a conventional example.

FIG. 34 is a partial perspective view of a conventional example.

FIG. 35 is a schematic configuration diagram of a conventional example.

[Explanation of symbols]

20 Engine 23 Intake pipe 24 Collector 25 Branch pipe 26 Throttle body 27 Throttle valve 27a Backward free end 27b Forward tilt free end 30 exhaust pipe 31 EGR passage (exhaust gas recirculation passage) 32, 33 passage 34,35 Gas inlet 40 Guide Case 45, 46 Gas inlet 50, 51 Gas inlet 55,56 Gas inlet 60, 61 gas inlet 62 Bent

Continuation of front page (56) References JP-A-49-117829 (JP, A) JP-A-10-77913 (JP, A) JP-A-9-317569 (JP, A) JP-A-9-256914 (JP, A) JP-A-9-217659 (JP, A) JP-A-9-209848 (JP, A) JP-A-9-195859 (JP, A) JP-A-9-158789 (JP, A) 8-319900 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 25/07 580 F02M 35/10 311

Claims (10)

(57) [Claims] An intake system provided with a throttle valve upstream of an intake pipe having a branch pipe connected to each cylinder and a collector, and an EGR gas supplied from an exhaust system via an external recirculation path to a rear side of the intake system throttle valve. In the exhaust gas recirculation device for the engine introduced into the intake pipe upstream of the collector, the EGR gas introduction port to the intake pipe of the external recirculation path is provided in the reverse flow area behind the free end of the throttle valve in the closed state.
Arranged than the circumference tangential direction of the intake pipe section at a position along, and this was suited to the cross section in a direction perpendicular against the axial direction of the intake pipe <br/> an exhaust gas recirculation system for an engine according to claim. 2. The exhaust gas recirculation system for an engine according to claim 1, wherein the EGR gas inlet is disposed at a position behind the free forward end of the throttle valve and at a position behind the free backward end of the throttle valve. 3. An EG on a free front end side of a throttle valve.
3. The exhaust gas recirculation device for an engine according to claim 2, wherein the R gas introduction port and the EGR gas introduction port on the rearward free end side are opened in a cross flow manner facing each other. 4. An EG on a free front end side of a throttle valve.
3. The cross-sectional area of the R gas inlet is larger than the cross-sectional area of the EGR gas inlet on the rearward free end side.
An exhaust gas recirculation device for an engine according to Claim 1. 5. The EG on the free rear end side of the throttle valve.
3. The exhaust gas recirculation device for an engine according to claim 2, wherein auxiliary air is introduced from the R gas introduction port instead of the EGR gas. 6. The exhaust gas recirculation device for an engine according to claim 1, further comprising a guide case for projecting the EGR gas introduction port into the intake pipe. 7. The exhaust gas recirculation device for an engine according to claim 1, wherein the cross-sectional shape of the EGR gas inlet is formed in an elliptical shape. 8. An EGR gas in which an opening area of an EGR gas inlet is corrected by a maximum speed of fresh air passing through a throttle valve, a distance from a throttle valve shaft center to an EGR gas inlet, and an opening shape of the EGR gas inlet. The exhaust gas recirculation device for an engine according to claim 1, wherein the exhaust gas recirculation device is set in accordance with the blowing speed. 9. An intake pipe including a throttle chamber,
Bend with the forward free end of the throttle valve inside
If you have a throttle valve according to its turn
The position of the EGR gas inlet on the free front end is set to the downstream side,
The position of the EGR gas inlet on the free tilt end side is changed to the forward free end
3. The exhaust gas recirculation device for an engine according to claim 2 , wherein the correction is made to the downstream side at a larger ratio than the EGR gas inlet on the side . 10. An intake pipe including a throttle chamber.
However, there is a tune with the rear free end of the throttle valve inward.
If you have a bend, the throttle valve
The position of the EGR gas inlet on the free end side
Then, the position of the EGR gas inlet port on the free end side
Upstream at a smaller ratio than the free end side EGR gas inlet
3. The engine according to claim 2, wherein the engine speed is corrected.
Exhaust gas recirculation device.