KR100306187B1 - Exhaust gas recirculation system for engine - Google Patents

Abstract

The exhaust gas recirculation apparatus for returning a part of the exhaust gas of the engine to the intake apparatus includes first and second gas inlets for directing the EGR gas downstream of the intake air passage of the throttle valve. The first and second inlets are respectively opened downstream of the first and second mixing positions of the first and second swing ends of the directional throttle valve, and efficiently mix and deposit the EGR gas with fresh intake air. Inclined downstream with respect to the longitudinal direction of the intake passage.

Description

Engine unit equipped with exhaust gas recirculation unit of engine and EGR unit {EXHAUST GAS RECIRCULATION SYSTEM FOR ENGINE}

The content of Japanese Patent Application No. Hei 9-142381, filed May 30, 1997, is incorporated herein by reference.

The present invention relates to an exhaust gas recirculation (EGR) device for returning a portion of the engine's exhaust gas to the intake apparatus to improve fuel efficiency and exhaust performance.

With increasing environmental concern, a controlled amount of exhaust gas is recycled to the intake unit during normal operation, which does not require high power, to improve fuel consumption and reduce nitrogen oxides (NO _X ) for CO ₂ reduction. Various EGR devices have been proposed for this purpose.

Japanese Laid-Open Patent Publication No. H3-114563 discloses a conventional first EGR device having a pair of horizontally facing openings for introducing EGR gas into an intake pipe. Japanese Unexamined Patent Application, First Publication No. 3-114564 discloses a conventional second EGR apparatus having an annular EGR gas passage and a plurality of holes around the intake pipe for introducing EGR gas from the annular passage into the intake pipe. All of the above devices are intended to reduce the non-uniformity of the EGR rate between cylinders.

Japanese Patent Laid-Open No. 8-218949 discloses a conventional third EGR device having an EGR passage opening in a second surge tank provided downstream of a first surge tank in an intake passage. Such a device introduces EGR gas at a location remote from the throttle valve to block the attachment of harmful components (deposit) to the throttle valve of the exhaust gas mixture.

However, conventional EGR devices are not fully enough to mix EGR gas with intake air and to distribute the EGR gas uniformly to the engine cylinder. In the second device, the fresh intake air flow state through the throttle valve has a significant effect on the mixing of the EGR gas and the attachment of the deposit to the throttle valve. Inadequate mixing of EGR gas with intake air causes uneven distribution of EGR rates in the cylinder, unstable engine performance, increased emissions and poor fuel consumption. Deposition on throttle valves reduces the accuracy of intake air volume control.

It is therefore an object of the present invention to provide an exhaust gas recirculating engine device for maintaining a constant EGR distribution in an engine cylinder and to protect the throttle valve against deposits.

According to the invention, the exhaust gas recirculation device of the engine comprises an exhaust device, an intake device and an EGR device. Intake devices include piping or piping and throttle valves. The tubing is a single member or assembly (such as the assembly of the intake manifold and the throttle body) for forming a passageway for distributing intake air to the cylinder of the engine. The piping includes a collector, a plurality of branch pipes from the collector to the cylinder of the engine, respectively, and an intake passage for introducing intake air into the collector. The throttle valve is disposed in the intake passage portion at an intermediate position such that the intake passage portion is separated into an upstream intake passage section on an upstream side of the throttle valve and a downstream intake passage system extending from the throttle valve to the collection portion.

The EGR device is arranged to return a portion of the exhaust gas as the EGR gas from the exhaust device into the downstream passage system of the intake apparatus. The EGR apparatus includes at least one EGR gas inlet with an EGR gas introduction opening for directing the incoming EGR gas flow to the downstream passage system. The EGR gas introduction opening is disposed downstream of the first free end of the throttle valve in the closed position. The EGR gas introduction port extends along a tangential direction which is tangent to the curved inner wall surface of the downstream passage system. The inflow direction of the EGR gas inlet is inclined downstream to form a predetermined angle with respect to the fresh intake air flow direction of the downstream intake passage system.

Thus, the EGR inlet leads to the generation of threaded spirals that travel downstream along the inner surface of the intake passage system. The intake air stream is attracted into the spiral and mixes well with the EGR gas. The spiral promotes the mixing of the EGR gas and the intake air and prevents deposition by leaving the EGR gas outside the backflow zone behind the throttle valve.

1 is a schematic diagram showing an engine device having an EGR inlet port according to a first embodiment of the present invention;

Fig. 2 shows the arrangement of an EGR inlet port according to the first embodiment.

Fig. 3 shows the arrangement of an EGR inlet port according to the first embodiment.

4 is a graph showing an EGR region.

5 and 6 show the flow on the downstream side of the throttle valve.

7 is a graph showing the relationship between the throttle opening and the reverse flow region.

Figures 8 and 9 show the magnitude of the backflow region under low and high load conditions.

10-14 illustrate EGR gas diffusion from various introduction positions.

15, 16 and 17 show spirals generated by the EGR inlet according to the first embodiment of the present invention.

18 is a diagram showing a moving distance of an EGR gas along a spiral passage according to the first embodiment of the present invention.

Fig. 19 is a graph showing the improvement of the cylinder EGR distribution in the cylinder by the spiral EGR passage shown in Fig. 18;

20A and 20B are schematic views showing the EGR introduction position according to the first embodiment.

Fig. 21 is a graph showing the improvement of deposit prevention by the EGR introduction position according to the first embodiment.

Fig. 22 is a schematic diagram showing a gas inlet port of an EGR device according to the second embodiment of the present invention.

Fig. 23 is a schematic diagram showing an arrangement of introduction ports according to the second embodiment.

Fig. 24 is a schematic diagram showing an arrangement of introduction ports according to the second embodiment.

Fig. 25 is a schematic diagram showing a gas inlet port of the EGR device according to the third embodiment of the present invention.

Fig. 26 is a schematic diagram showing an arrangement of introduction ports according to the third embodiment.

Fig. 27 is a schematic diagram showing a gas inlet port of the EGR device according to the fourth embodiment of the present invention.

Figure 28 is a schematic diagram showing an EGR introduction position according to the fifth embodiment of the present invention.

Fig. 29 is a graph showing the factors for determining the gas inlet port of the EGR apparatus according to the sixth embodiment of the present invention.

30 and 31 show the effect of the gas introduction port according to the sixth embodiment.

32 is a schematic diagram showing an inlet opening of an EGR device according to a seventh embodiment of the present invention;

33 is a graph showing the EGR introduction position according to the seventh embodiment;

<Description of the code | symbol about the principal part of drawing>

20: engine

21: intake manifold

22: exhaust manifold

25: branch pipe

27: throttle valve

34: first introduction port

35: second inlet

1 to 3 show an engine device according to a first embodiment of the present invention.

The engine apparatus shown in FIG. 1 includes an engine 20, an intake apparatus, an exhaust apparatus, and an EGR apparatus for returning a part of the exhaust gas as the EGR gas from the exhaust apparatus to the intake apparatus.

The intake apparatus includes piping (piping or piping) for distributing intake air to the cylinder of the engine 20. The intake piping of this example includes an intake manifold 21 and a throttle body 26 for forming an intake passage device for distributing intake air to the engine cylinder. The exhaust device includes an exhaust manifold 22 for transporting exhaust gas away from the cylinder of the engine 20.

The intake manifold 21 of this example is the inflow pipe part 23, the collection part 24 which has the predetermined volume extended from the inflow pipe part 23, and the collection part 24 from the collection part 24 to the cylinder of the engine 20, respectively. A set of branching tubes 25 extending.

The throttle body 26 is connected to the intake manifold 21 on the upstream side of the inflow pipe part 23. The throttle body 26 and the inlet pipe portion 23 form an intake air passage for introducing intake air into the collection portion 24 of the intake manifold 21. The throttle body 26 has a throttle valve 27 therein. The throttle valve 27 is disposed in the intake air passage. On the downstream side of the throttle valve 27, the downstream passage portion of the intake passage extends to the collecting portion 24.

The exhaust manifold 22 includes a set of branch pipes 28 extending from the engine cylinder and an exhaust pipe portion 30 where the branch pipes 28 gather.

The EGR apparatus includes an EGR passage 31 for exhaust gas recirculation. The EGR passage 31 branches from the exhaust pipe portion 30. As shown in FIG. 3, the EGR passage 31 of this example is provided with a first and second branch passageway leading to the inlet pipe portion 23 of the intake manifold 21 between the throttle valve 27 and the collecting portion 24. 32, 33) into two branches. The EGR gas from the exhaust device flows into the intake air flow of the intake air passage at the confluence point disposed in the downstream passage portion downstream of the throttle valve 27 and upstream of the collecting portion 24.

The first branch passage 32 opens the first EGR gas introduction opening opened into the inlet pipe 23 at the first EGR introduction position disposed behind the downstream free end 27a of the throttle valve 27 in the closed position. The first inlet 34 provided is provided. The second branch passage 33 opens the second EGR gas introduction opening opened into the inlet pipe 23 at the second EGR introduction position disposed behind the upstream free end 27b of the throttle valve 27 in the closed position. The provided 2nd introduction port 35 is provided.

The inlet pipe part 23 of this example has a circular cross section as shown in FIG. As shown in Fig. 3, each of the first and second inlets 34 and 35 extends along the tangent of the circular cross section of the inlet pipe section 23. As shown in Figs. The first and second inlets 34 and 35 are arranged such that the inflow directions of the first and second inlets 34 and 35 are opposite to each other as shown in FIG. The first and second inlets 34, 35 are open in opposite directions in a cross flow (or countercurrent) manner. As shown in Fig. 2, each inlet 34, 35 is inclined downstream to form a predetermined angle [theta] (lead angle) with respect to the fresh intake air flow direction in the inlet pipe portion 23. As shown in FIG.

The inlets 34 and 35 can be arranged arbitrarily so that the inlets 34 and 35 respectively extend from opposite directions. In this case, the inlet 34 extends from the left side of FIG. 3 and the inlet 35 extends from the right side.

4 shows the commercial operation region and the EGR region of the engine according to the engine speed and the throttle opening degree. In the commercial operating zone, the zone where the EGR is used is a zone formed by excluding the high load zone near the full throttle and the low load zone near the idle state.

5 and 6 show the flow in the inlet duct 23 on the downstream side of the throttle valve 27, seen from the direction perpendicular to the axis of the throttle valve 27 and parallel to the axis of the throttle valve 27. It is. Through the open zone between the throttle valve 27 and the inner wall surface of the inlet pipe 23, the main stream flows downstream towards the collector 24. Behind the throttle valve 27, a back flow region appears. The size of the reverse flow zone depends on the opening degree of the throttle valve 27 as shown in FIG. 8 and 9 show the backflow patterns in the high load operating region and the low load region. The counter flow zone becomes larger when the opening degree of the throttle valve 27 is small.

The position of the EGR gas introduction point A affects the flow in the inlet pipe part 23 as shown in Figs.

In the example of Fig. 10, the EGR gas is introduced horizontally at the downstream position of the reverse flow region behind the throttle valve 27. In this case, the EGR gas is spread from the free ends 27a and 27b of the throttle valve 27 between the upper main stream and the lower main stream, respectively. Thus, the EGR gas is conveyed away quickly towards the collector 24 before it is fully diffused. The EGR confluence position in Fig. 10 is beneficial for the prevention of deposition but not for mixing with fresh intake air.

In the example of Fig. 11, the EGR gas is introduced horizontally into the reverse flow zone near the throttle valve 27. The EGR gas is pushed backwards by backflow and hits the throttle valve 27 directly, causing undesirable deposition.

In the example of Fig. 12, the EGR gas is introduced horizontally at a position near the downstream end of the counter flow zone. The change in the engine load condition caused by the change in the road frame opening has a strong influence, and the mixing of EGR gas and fresh intake air, and prevention of depositing are all unstable. Such instability is particularly increased when the amount of EGR is increased.

In the example of Figures 13 and 14, the EGR gas is introduced vertically. The countercurrent zone affects the mixing performance and deposition prevention of the EGR gas and fresh intake air in the same manner as the examples of FIGS. 10 and 11. In the example of FIG. 13, the EGR gas forms a drift stream separate from the fresh intake air stream coming out of the free end of the throttle valve 27 without mixing with the fresh air stream. In the example of Figure 14, the flow rate of the EGR gas will affect the performance. When the EGR gas flow is fast and strong, the EGR flow traverses the mainstream vertically and increases undesirable deposits. When the EGR gas flow is weak, the EGR gas forms a separate stream that is detrimental to gas mixing.

FIG. 7 shows how the countercurrent influences the mixing of EGR gas with fresh intake air and the formation of deposits.

From above, the requirement to promote mixing of EGR gas with fresh intake air and to prevent deposits is provided by: I) avoiding backflow, ii) increasing residence time of EGR gas, and iii) throttle valve 27. The mixing of the EGR gas from both free ends into the mainstream of fresh intake air.

In order to meet this requirement, the EGR device according to the invention is adapted to produce at least one EGR for the production of spirals mixed with fresh liquor (main and lower liquor) from the free ends 27a and 27b of the throttle valve 27. A gas inlet is adopted.

In the example shown, the first confluence point of the EGR gas of the first inlet 34 is disposed just behind the downstream free end 27a of the throttle valve 27 in the closed position of the valve, and the second inlet ( The second confluence point of the EGR gas of 35 is disposed just behind the upstream free end 27b of the throttle valve 27 in the closed position of the valve. Each inlet 34, 35 extends along a line tangential to the circular cross section of the inlet tube 23, and each inlet 34, 35 is predetermined for the fresh intake airflow direction in the inlet tube 23. It is inclined downstream to form an angle θ (lead angle) of. In addition, the first and second inlets 34, 35 are opened in a cross flow manner (or countercurrent) in the opposite direction. Thus, the EGR gas is mixed with fresh intake air outside the counterflow zone at the mixing position where the fresh liquor velocity is the fastest, and the EGR gas and intake air are collected on the cylindrical inner wall surface of the inlet pipe section 23 and in the vicinity thereof. To form spirals flowing spirally towards

Therefore, the EGR gas stays for a very long time compared with the conventional design. Fresh intake air mainstream is included with the spiral of the EGR gas, and the EGR gas is directed from the outside to the center of the inlet pipe 23 during the spiral flow. Spreads towards. The EGR gas will stay outside the backflow region without causing deposition. The EGR device of this embodiment can sufficiently mix the EGR gas with the intake air, and can evenly distribute the EGR gas in the cylinder or effectively prevent depositing.

As shown in Fig. 18, the distance L2 moved by the EGR gas to the upstream branch pipe 25 along the spiral flow path (corresponding to the residence time) is much more than the distance L1 of the conventional straight path. long. As shown in Fig. 19, the degree of irregularity of EGR gas distribution in the cylinder is reduced by increasing the EGR gas travel distance.

As shown in Figs. 20 and 21, the upper and lower EGR introduction positions according to this embodiment can sufficiently prevent the formation of deposits as compared with the central EGR introduction position.

The engine apparatus according to the first embodiment of the present invention can make the EGR ratio of the cylinder even when the amount of EGR is large, thereby improving fuel consumption and exhaust performance. In addition, the engine device according to this embodiment can accurately control the amount of intake air by preventing deposition.

22 to 24 show an EGR device according to a second embodiment of the present invention. Each EGR inlet 34, 35 includes a guide case 40 defining an EGR inlet opening. In this example, the guide case 40 of each inlet is cylindrical and projects into the inlet pipe 23. In the example shown in Fig. 24, each inlet has an EGR inlet opening in a imaginary plane including the axis of the inlet pipe section 23. The axis of the throttle valve 27 is orthogonal to this plane.

The guide case 40 of each inlet 34 and 35 is for generating spirals which flow downstream as in the first embodiment, and is opened at a position that attracts the intake mainstream or the downstream mainstream into the spirals. . The outer cylindrical surface of each guide case 40 exposed inside the inlet pipe section 23 serves as a deflector for guiding and guiding fresh intake airflow (mainstream or downstream) in the direction of spiral flow. do.

By using the inner wall surface and outer wall surface of the guide case 40 to reinforce spirals, the EGR device of the second embodiment can sufficiently mix the EGR gas with the intake air, and uniformly distribute the EGR gas in the cylinder. And depositing can be prevented by keeping the EGR gas away from the backflow region.

25 and 26 show an EGR device according to a third embodiment of the present invention. In this embodiment, the gas introduction openings of each inlet 45, 46 are in the form of an elongated circle. The cross-sectional shape of each inlet port 45, 46 is elongated along the longitudinal direction of the inlet pipe section 23 as shown in FIG. In this example, the cross-sectional size of the opening of the second inlet port 46 behind the upstream end 27b of the throttle valve 27 is equal to the opening of the first inlet port 45 behind the downstream valve end 27a. Larger than the cross-sectional size.

The long openings in the first and second inlets 45, 46 allow the distance between the throttle valve 27 and the EGR gas introduction position to be reduced and to facilitate the mixing of the EGR gas with fresh intake air. You can increase the distance to). The first EGR gas inlet 45 is arranged on the side where the region of fresh intake air liquor is relatively narrow, and the second EGR gas inlet 46 is arranged on the side where the region of fresh intake air liquor is relatively wide. Thus, the smaller inlet 45 and the larger inlet 46 can introduce the EGR gas efficiently and keep the EGR gas out of the backflow region.

27 shows an EGR device according to a fourth embodiment of the present invention. In this embodiment, the EGR gas is introduced from an inlet 51 disposed downstream of the upstream end 27b of the throttle valve 27, while auxiliary air is introduced from the downstream end 27a of the throttle valve 27. It is introduced from the downstream inlet 50. Inlets 50 and 51 are directed and open as in the previous embodiment. Thus, in this embodiment, the inlet 51 is connected to the exhaust device, and the inlet 50 is connected to the intake device at a position upstream of the throttle valve 27. In this example, the inlet 50 is connected to an air cleaner on the upstream side of the throttle valve 27.

The EGR device of this example can increase the strength of spirals and can evenly mix the EGR gas. In this example, the inlet 50 for auxiliary air is arranged on the side where the intake air mainstream region is narrow. Thus, the EGR device can more effectively block the EGR gas from entering the countercurrent zone and prevent the deposit from being generated.

Fig. 28 shows an EGR device according to the fifth embodiment. The downstream inclination angle θ (lead angle) of each EGR gas inlet (shown in FIG. 2) is the most upstream branch pipe of the intake manifold 21 along the longitudinal center line of the inlet pipe section 23 from the EGR gas inlet position. The distance to the inlet of 25 is determined to be longer than one pitch (lead) of the spiral defined by the angle θ on the inner cylindrical surface of the inlet tube section 23.

Therefore, this design makes the moving distance of the EGR gas along the spiral path from the EGR gas confluence point to the inlet of the most upstream branch pipe 25 sufficiently long, and ensures proper mixing of the EGR gas and intake air.

Fig. 29 is a graph showing the sixth embodiment of the present invention. In this embodiment, the opening size (or opening area) of each of the first and second EGR inlets 55, 56 is the maximum flow rate of fresh intake air through the throttle valve 27 and the throttle valve 27. Of the EGR gas discharge flow rate (the flow rate of the EGR gas flowing into the inlet pipe section 23) changed by the distance between the shaft of the shaft and the openings of the gas inlets 55 and 56, and the opening shape of the inlet ports 55 and 56. Is determined.

As shown in Fig. 29, the flow rate of fresh liquor decreases as the distance from the throttle valve 27 in the downstream direction increases. The opening size and shape of the inlets 55 and 56 are determined such that the discharge flow rate of the EGR gas from each inlet 55 and 56 is always kept fast compared to the flow rate of the mainstream near the opening of the inlet. The setting of the EGR inflow rate is set higher than the fresh liquor speed as shown in FIG.

Thus, each inlet 55, 56 receives the EGR gas at a sufficient rate to produce strong spirals as shown in FIG. 30 without losing its speed due to collision with the mainstream as shown in FIG. 23) flow into. The EGR gas flows along the spiral path without turning inward toward the center of the inlet pipe portion 23 and stays away from the backflow region without causing deposition. The larger flow rate EGR flow of FIG. 30 can prevent deposits and can efficiently mix the EGR gas.

32 shows a part of an engine apparatus according to the seventh embodiment of the present invention. The intake passage formed by the inlet pipe section 23 and the throttle body 26 is connected to the collecting section 24 to form the bent portion 62 at an angle α in an imaginary plane orthogonal to the axis of the throttle valve 27. Inclined to the longitudinal direction. In this embodiment, the positions of the openings of the first and second inlets 60 and 61 are adjusted according to the bending angle α.

In the example shown in FIG. 32, the longitudinal center line of the intake air passage is bent downward with respect to the longitudinal direction of the collecting part 24, so that the upstream end 27b of the throttle valve 27 is the inner side of the bend 62. As shown in FIG. Is disposed on. In this case, the gas introduction position of the inlet port 61 disposed downstream of the upstream free end 27b of the throttle valve on the inner side of the bent part 62 is moved slightly downstream, and on the outer side of the bent part 62. The gas introduction position of the inlet port 60 arranged downstream of the downstream free end 27a of the throttle valve is moved further downstream according to the downward bending angle. As a result, the longitudinal distance from the axis of the throttle valve 27 to the confluence point of the inlet port 60 on the outside of the bend 62 along the longitudinal direction of the inlet pipe portion 23 is determined from the axis of the throttle valve 27 by the bend portion ( Longer than the longitudinal distance to the confluence of the inlet 61 on the inside of 62.

When the longitudinal center line of the intake air passage is bent upward with respect to the longitudinal direction in which the collector 24 extends so that the downstream end 27a of the throttle valve 27 is disposed on the inside of the bend, then the inside of the bend The EGR gas introduction confluence position of the introduction port 60 disposed downstream of the downstream free end 27a of the throttle valve on the side is moved upstream according to the upward bend angle, and the throttle valve 27 on the outside of the bend 62 is provided. The confluence position of the inlet 61 disposed downstream of the upstream free end 27b of s) is shifted less upstream as shown in FIG.

When the inlet pipe 32 has a downward bend angle as shown in Fig. 32, the counter flow zone moves toward the outside of the bend. Therefore, the EGR gas introduction confluence positions of the inlets 60 and 61 are moved downstream so that the confluence positions of the inlets 60 are moved away from the backflow region. When the inlet pipe part has an upward bend angle, the counter flow zone moves toward the center of the inlet pipe part 23. In this case, the confluence positions of the inlets 60 and 61 are moved upstream to increase the moving distance of the EGR gas.

Thus, the inlets 60 and 61 are opened at the optimum positions for the shape of the countercurrent region. Therefore, the design of this embodiment allows the EGR gas to be effectively mixed and deposition can be prevented.

As shown in Fig. 3, the swing shaft of the throttle valve 27 according to each shown embodiment of the present invention extends in the virtual first center plane C1. The virtual second center plane C2 crosses the first center plane C1 at right angles along the center line of the cylindrical inflow pipe part 23. The inlet pipe part 23 in the example shown is straight and in the form of a hollow right circular cylinder. The first and second virtual tangential surfaces T1 and T2 are parallel to the first central plane C1 and abut the cylindrical inner wall surfaces of the inlet pipe part 23 on both sides of the first central plane C1. The third and fourth virtual tangential surfaces T3 and T4 are parallel to the second central plane C2 and abut the cylindrical inner wall surfaces of the inlet pipe part 23 on both sides of the second central plane C2. In FIG. 2, the virtual cross section S is a plane perpendicular to the centerline of the inlet pipe 23 and parallel to the axis of the throttle valve 27.

In the example shown in FIGS. 2 and 3, the first inlet 34 extends along the first tangential plane T1 from the first side (right face) of the second central plane C2, and the fourth tangential plane. Open toward T4. The second inlet 33 extends along the second tangential surface T2 from the second side surface (left side surface) of the second central plane C2 and opens toward the third tangential surface T3.

Each of the first and second inlets 34, 35 of this example is circular in cross section. The cylindrical inner wall surface of the first inlet 34 is located on the first tangential surface T1 and includes a straight line in contact with the cylindrical inner wall surface of the inlet pipe section 23 at the point indicated by reference numeral M1 in FIG. 3. do. The cylindrical inner wall surface of the second inlet 35 is located on the second tangential surface T2 and includes a straight line contacting the cylindrical inner wall surface of the inlet pipe section 23 at the point indicated by reference numeral M2 in FIG. 3. do. The longitudinal direction of each inlet 34, 35 forms a cross section S and an angle θ as shown in FIG. 2. The first and second inlets 34 and 35 are inclined from the cross-section S in a direction to generate spirals flowing downstream toward the collecting section 24. The spiral flow direction generated by the first inlet 34 is the same as the spiral flow direction of the second inlet 35. In the example of FIG. 3, the spiral is counterclockwise.

Thus, the intake airflow is attracted into the spirals to mix well with the EGR gas, which promotes the mixing of the EGR gas and the intake air, and leaves the EGR gas outside the countercurrent behind the throttle valve to prevent deposition. It becomes possible.

Claims (20)

In the exhaust gas recirculation apparatus of an engine comprised of an exhaust apparatus, an intake apparatus, and an EGR apparatus for conveying exhaust gas away from an engine, The intake apparatus includes a pipe for distributing intake air to a cylinder of the engine, the pipe including a collector, a plurality of branch pipes from the collector to each of the cylinders of the engine, and an intake passage for introducing the intake air into the collector. And an intake apparatus further comprising a throttle valve disposed in the intake passage portion at an intermediate position, wherein the intake passage portion is separated into an upstream intake passage system on an upstream side of the throttle valve and a downstream intake passage system extending from the throttle valve to the collection portion; , The EGR device includes an EGR gas inlet with an EGR gas introduction opening for returning a portion of the exhaust gas as the EGR gas from the exhaust device into the downstream passage system of the intake apparatus and for directing the incoming EGR gas flow to the downstream passage system, The EGR gas introduction opening is disposed downstream of the first free end of the throttle valve in the closed position, the EGR gas introduction port extends along a tangential direction in contact with the curved inner wall surface of the downstream passage system, and the inflow direction of the EGR gas introduction port is the downstream passage system. The exhaust gas recirculation apparatus of the engine, characterized by inclining downstream to form a predetermined angle with respect to the fresh intake air flow direction. The exhaust gas recirculation apparatus of claim 1, wherein the EGR inlet includes a guide case protruding into the downstream passage system. The exhaust gas recirculation apparatus of claim 1, wherein the EGR inlet has a shape having a long cross section. 2. The EGR inlet of claim 1 wherein the EGR inlet extends along a predetermined tangential to the virtual helix on the curved inner wall of the downstream passageway, the lead of the helix being smaller than the distance between the EGR inlet opening and the inlet of any branch of the pipe. An exhaust gas recirculation apparatus of an engine, characterized in that. The opening area of the EGR gas introduction opening is determined by the maximum flow rate of fresh intake airflow through the throttle valve, the distance from the axis of the throttle valve and the EGR gas introduction opening, and the opening form of the EGR gas introduction opening. Exhaust gas recirculation apparatus for an engine, characterized in that it is determined by the flow rate of the corrected EGR gas inlet flow. The complementary inlet opening of claim 1, wherein the EGR device further comprises a complementary inlet having a complementary inlet opening for directing inlet gas flow into the downstream intake passage between the throttle valve and the collector, the complementary inlet opening being in a closed position. Disposed downstream of the second free end of the throttle valve, the complementary inlet extends along a tangential direction in contact with the curved inner wall surface of the downstream intake passage system, and the inflow direction of the complementary inlet passage is a fresh air flow direction of the downstream intake passage system. Inclined downstream to form a predetermined angle relative to the engine, wherein the EGR gas inlet and the complementary inlet extend from both directions such that the inflow direction of each EGR and the complementary inlet is opposite to the inflow direction of the other; Exhaust gas recirculation unit. 7. The throttle of claim 6, wherein the cross-sectional size of the EGR gas introduction opening disposed downstream of the first free end of the throttle valve is greater than the cross-sectional size of the complementary introduction opening disposed downstream of the second free end of the throttle opening. And the first free end of the valve is disposed upstream of the second free end when the throttle valve is in the closed position. 7. The exhaust gas recirculation apparatus of an engine according to claim 6, wherein both the EGR inlet and the complementary inlet are connected to an exhaust device to introduce the EGR gas into the downstream intake passage system through both inlets. The throttle valve according to claim 6, wherein the complementary inlet is connected to the intake device to introduce fresh air into the downstream intake passage system through the complementary inlet, the EGR inlet is connected to the exhaust device, and the second free end of the throttle valve is the throttle valve. Exhaust gas recirculation device of the engine, characterized in that it is disposed downstream of the first free end when the is in the closed position. 7. The intake passage portion according to claim 6, wherein the intake passage portion has a bent portion with respect to the collecting portion along a plane perpendicular to the axis of the throttle valve, and the position of the EGR inlet opening and the complementary inlet opening is at a bending angle between the intake passage portion and the collecting portion. The exhaust gas recirculation apparatus of the engine, characterized in that corrected accordingly. An engine device comprising a plurality of engine cylinders, an exhaust device for transporting exhaust gas away from the engine, an intake device, and an EGR device, The intake apparatus comprises a collecting portion, a plurality of branch pipes each extending from the collecting portion to one of the engine cylinders for distributing intake air to the engine cylinder of the engine, and a piping consisting of an intake passage portion for introducing the intake air into the collecting portion. Wherein the intake apparatus further comprises a throttle valve disposed in the intake passage portion, the intake passage portion upstream of the throttle valve and a downstream intake passage system extending from the throttle valve to the collection portion on the downstream side of the throttle valve. Including, The EGR apparatus includes a first gas inlet for returning a portion of the exhaust gas as the EGR gas from the exhaust apparatus to the downstream intake passage system of the intake apparatus, and directing the inflow gas flow to the downstream intake passage system, wherein the first inlet port Inclined in the direction of generating spirals along the curved inner wall surface of the passage system toward the collecting portion, the first inlet opening being opened in the downstream intake passage system at a position downstream of the first swing end of the throttle valve, An inlet flow is caused to flow into a fresh air stream exiting a gap between the first swing end of the throttle valve in the closed position and the inner wall surface of the intake passage portion. 12. The inlet of claim 11, wherein the first inlet extends along a slope that is inclined from an imaginary plane of the downstream intake passage system in a direction to form a spiral flowing downstream toward the collector along the inner wall surface of the downstream intake passage system. An engine apparatus provided with the EGR apparatus characterized by the above-mentioned. 13. An inner wall surface of a downstream intake passage system as set forth in claim 12, wherein the first inlet port comprises a virtual first center plane including a swing shaft on which the throttle valve swings and a center line of the downstream intake passage system, and a cylindrical surface parallel to the first center plane. The first introduction port lies on a virtual second center plane extending along the first tangential plane and intersecting at a right angle with the first center plane along the centerline of the downstream intake passage system. An engine device with an EGR device, characterized in that is opened to the first mixing position. The first tangential surface of claim 13, wherein the first inlet port is disposed on the first tangential surface and is formed with a first tangential surface along an inclined imaginary first tangent that forms a predetermined lead angle with an imaginary plane perpendicular to the centerline of the downstream intake passage system. And a cylindrical inner wall surface in contact, wherein the first inlet extends along an inclined tangent to reach a position where the first inclined line intersects the second central plane. 15. The intake passage of claim 14 wherein the EGR device includes a second gas inlet for directing an inlet gas flow into a downstream intake passage system of the intake device, the second inlet being downstream of the second swing end of the throttle valve. Open to the system so that the inflow flow from the second inlet flows into a fresh air stream exiting the gap between the second swing end of the throttle valve in the closed position and the inner wall surface of the intake passage, the first and second inlet being simulated Disposed on both sides of the first central plane, the first and second inlets being disposed on the first and second sides of the virtual second center plane, respectively, the first inlet being from the first side of the second central plane. Extends and opens toward a second side of the second center plane, the second inlet extends from the second side of the second center plane and opens toward the first side of the second center plane, respectively the first and second Inlet is An engine unit having an EGR device, characterized in that the inclined plane from the top. 16. An engine apparatus according to claim 15, wherein each of the first and second inlets terminates in a second central plane. 16. The engine apparatus according to claim 15, wherein each of the first and second inlets has an elongate shape along the centerline of the downstream intake passage system. The method of claim 15, wherein the first inlet has a first inlet opening disposed downstream of the first oscillating end of the throttle valve in the closed position and the second inlet is downstream of the second oscillating end of the throttle valve in the closed position. Having a second inlet opening arranged, the first swing end being disposed on a downstream side of the swing shaft of the throttle valve, the second swing end of the throttle valve being disposed on an upstream side of the swing shaft of the throttle valve, An engine device with an EGR device, characterized in that the first inlet opening is smaller in size than the second inlet opening. 16. The downstream intake passage system and the collecting portion of the downstream intake passage system are connected at their ends to form a bend forming a predetermined angle within the second central plane, such that the longitudinal centerline of the downstream intake passage system has the collecting portion in the second central plane. Intersects a longitudinal line extending at an intersection within, one of the first and second inlets is an outer inlet disposed on the outside of the bend, and the other of the first and second inlets is disposed on the inside of the bend And the distance of the open end of the external inlet from the swing shaft of the throttle valve along the centerline of the downstream intake passage system is the distance of the open end of the internal inlet from the swing shaft of the throttle valve along the centerline of the downstream intake passage system. An engine device with an EGR device characterized in that it is larger. An engine device comprising a plurality of engine cylinders, an exhaust device for transporting exhaust gas away from the engine, an intake device, and an EGR device, The intake apparatus comprises a collecting portion, a plurality of branch pipes each extending from the collecting portion to one of the engine cylinders for distributing intake air to the engine cylinder of the engine, and a piping consisting of an intake passage portion for introducing the intake air into the collecting portion. Wherein the intake apparatus further comprises a throttle valve disposed in the intake passage portion, the intake passage portion upstream of the throttle valve and a downstream intake passage system extending from the throttle valve to the collection portion on the downstream side of the throttle valve. Wherein the downstream intake passage system has a cylindrical inner wall surface extending thereabout along a virtual centerline perpendicular to the virtual plane of the downstream intake passage system, The EGR device includes first and second gas inlets for returning a portion of the exhaust gas as the EGR gas from the exhaust device to the downstream intake passage system of the intake apparatus and for directing the first and second inlet gas flows to the downstream intake passage system. And the first inlet is opened to the first mixing position such that the first inlet flow from the first inlet meets the intake air mainstream in the downstream intake passage system at the first mixing position and the second inlet is in the second mixing position. Opened so that a second inflow from the second inlet meets the intake air mainstream in the downstream intake passage system at the second mixing position, the first mixing position comprising an oscillation axis of the throttle valve and a centerline of the downstream intake passage system. Disposed on the first side of the first central plane, the second mixing position being disposed on the second side of the first central plane, and of the first and second mixing positions lying on the virtual second center plane. All cross at right angles with the first central plane along the centerline of the downstream intake passage system, the first inlet extending from the first side of the second central plane towards the second central plane, the second inlet being the second central plane Extending from a second side of the toward the second central plane, the first and second inlets being inclined relative to the plane of the downstream intake passage system in a direction to create spirals towards the collection along the cylindrical inner wall surface of the downstream intake passage system; Engine device provided with the EGR apparatus characterized by the above-mentioned.