JPH10252577A - Egr distributing device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain variation of EGR rate among cylinders so as to prevent deterioration of exhaust performance by providing a conjunction part of an intake pipe and an EGR introduction pipe upstrea from an intake manifold, and providing an orifice in an inlet part of the intake manifold. SOLUTION: An EGR distributing device of an internal combustion engine having an EGR system is so constructed that an EGR introduction pipe 11 and an intake passage 12 are joined to each other in the middle between an intake throttle valve 21 and an intake manifold 1, and the EGR introduction pipe 11 is connected from the opposite direction to the intake port 2 side coupled to a cylinder head 50 through an EGR valve 13. An orifice 30 formed by a half-moon like projection is provided in an inlet part of the intake manifold 1, taking the intake port 2 side as a fitting position. When the half-moon orifice 30 is thus provided, the distribution of EGR gas and the exhaust performance can be remarkably improved without changing the lay-out of the intake system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an EGR distribution device for an internal combustion engine.

[0002]

2. Description of the Related Art As an EGR distribution device in an engine having a conventional EGR system, for example, Japanese Utility Model Laid-Open No. 1-1
As disclosed in U.S. Pat. No. 66253, there is a structure as shown in FIG. In this prior art, a groove is provided on the inner peripheral surface of a surge tank of an intake manifold so as to intersect with a flow direction of intake air, and exhaust gas is introduced into a side wall surface of the groove.
An opening for the GR gas passage is provided. This gives E
The distribution of GR gas is improved. Further, as another conventional technique, there is one having a structure as shown in FIG. In this prior art, EGR gas is mixed with fresh air using turbulence generated by a throttle.

[0003]

However, Japanese Utility Model No. 1-1
In the prior art described in Japanese Patent No. 66253, the diameter of an EGR gas introduction pipe is increased in order to increase the amount of EGR gas in order to further purify exhaust gas. As a result, in such a configuration, there is a problem in layout such that the intake manifold becomes large. Furthermore, with the increase in the amount of EGR gas and the expansion of the EGR region, it has been difficult to improve the EGR distribution over a wide range by such a method.
On the other hand, in the diesel engine described in Japanese Utility Model Laid-Open No. 17263/1991, the use area of the throttle valve is narrow, and such a method cannot be used. It is conceivable to use a turbulence generator such as an orifice instead of the throttle valve, but this increases the intake resistance and causes the charging efficiency to deteriorate.

The present invention has been made in view of such a conventional problem. In an internal combustion engine having an EGR system, a junction of an intake pipe and an EGR introduction pipe is provided upstream of an intake manifold, and an EGR introduction pipe is provided. It is an object of the present invention to solve the above-mentioned problem by providing a projection at the inlet portion of the intake manifold in a direction opposite to the introduction direction of the intake manifold.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an internal combustion engine having an EGR system, in which a junction of an intake pipe and an EGR introduction pipe is provided upstream of an intake manifold, and is provided at an inlet of the intake manifold. An orifice is provided.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, E of an internal combustion engine according to the present invention will be described.
An embodiment of a GR distribution device will be described in detail with reference to the accompanying drawings. FIG. 1 is a view showing one embodiment of an EGR distribution device for an internal combustion engine according to the present invention, and is a partially sectional perspective view showing a characteristic portion of the present invention in a cross section. FIG. 2 (a)
2 is a top view of FIG. 1, and FIG.
It is sectional drawing which shows the -A cross section.

First, the structure will be described. An EGR distribution device for an internal combustion engine according to a first embodiment is shown in FIGS.
As shown in (a), the EGR introduction pipe 11 and the intake passage 12
At the middle of the intake throttle valve 21 and the intake manifold 1. At this time, the EGR introduction pipe 11 is introduced from a direction opposite to the intake port 2 side connected to the cylinder head 50 via the EGR valve 13. A half-moon-shaped orifice 30 is provided at the inlet of the intake manifold 1 as shown in FIGS. This orifice 30
Are provided on the intake port 2 side.

Next, the operation of the embodiment will be described. FIG. 3 shows changes in the EGR rate and excess air rate (λ) of each cylinder with respect to the shape and mounting position of the orifice. As a result,
When the semilunar orifices are located on the intake port side and the opposite side, EGR distribution is overwhelmingly better on the intake port side. On the other hand, when the orifice shape is all around,
Although the distribution is improved, the excess air ratio (λ) in the EGR decreases due to the deterioration of the charging efficiency.

FIG. 4 shows changes in the EGR rate and the excess air rate (λ) in the present embodiment and when the orifice is not used. As can be seen from the results, when the orifice is not used, the EGR rate of the # 4 cylinder located immediately after the inlet decreases extremely, and increases at # 2. This is because the EGR introduction pipe is located opposite to the port side, so that the EGR gas initially flows on the side wall opposite to the port side and is gradually drawn toward the port side. By providing a semilunar orifice on the port side, cavitation occurs near the # 4 port, and EGR gas is drawn to the # 4 port inlet. On the other hand, when a semilunar orifice is provided on the side opposite to the port, cavitation occurs in the direction opposite to the port, and the effect cannot be obtained.

[0010] By improving the EGR distribution in the present embodiment, the exhaust performance is greatly improved as shown in FIG. Further, since the distribution can be improved without changing the layout of the intake system, and the half-moon orifice can be handled by changing the shape of the gasket, the cost is hardly increased.

[0011]

As described above in detail, according to the present invention, in the internal combustion engine having the EGR system, the confluence of the intake pipe and the EGR introduction pipe is provided upstream of the intake manifold. By providing the intake manifold inlet with a projection in the direction opposite to the pipe introduction direction, it is possible to suppress EGR rate variation between cylinders and prevent deterioration of exhaust performance.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of an EGR distribution device for an internal combustion engine according to the present invention.

2A is a top view of FIG. 1, and FIG. 2B is a cross-sectional view taken along the line AA in FIG.

FIG. 3 is a diagram showing changes in the EGR rate and excess air rate (λ) of each cylinder with respect to the shape and mounting position of an orifice.

FIG. 4 is a diagram showing the effect of the present invention.

FIG. 5 is a diagram showing the effect of the present invention on exhaust performance.

FIG. 6 is a diagram showing a conventional EGR distribution device.

FIG. 7 illustrates another prior art EGR distribution device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intake manifold 2 Intake port 11 EGR introduction pipe 12 Intake passage 13 EGR valve 21 Intake throttle valve 30 Half moon-shaped orifice

Claims (3)

[Claims] 1. An EGR distribution device for an internal combustion engine having an EGR system, wherein a junction of an intake pipe and an EGR introduction pipe is provided upstream of an intake manifold, and an orifice is provided at an inlet of the intake manifold. 2. The EGR distribution device for an internal combustion engine according to claim 1, wherein the intake manifold inlet is located at the rear or all of the engine, and the orifice provided at the intake manifold inlet is provided only on the intake port side. An EGR distribution device for an internal combustion engine, which is provided in 3. An EGR distribution device for an internal combustion engine according to claim 2, wherein a projection at an intake manifold inlet portion is provided in a direction opposite to a direction in which the EGR introduction pipe is introduced. apparatus.