JPH0821316A - Connecting construction of exhaust gas re-circulating device - Google Patents

Abstract

PURPOSE:To prevent thermal deformation of the connecting part of a connector with an intake manifold by connecting an exhaust tube to an intake manifold made of synthetic resin through an annular connector, forming heat releasing fins on the part nearby the exhaust tube of the connector, and facing the heat releasing fins to the intake air flow passage in the intake manifold so as to release the heat transmitted from exhaust gas to the intake air. CONSTITUTION:An exhaust gas tube 4 is connected to the opening 2 of an intake manifold 1 made of synthetic resin through a connector 3. The connector 3 is fixedly secured to the manifold by means of bolts 6, and formed with heat releasing fins 5 nearby the exhaust gas tube 4. Heat of exhaust gas is transmitted from the exhaust gas tube 4 to the connector 3, but released into intake air through the heat releasing fins 5, and hence heat influence is not applied to the connecting part of the connector outer circumferential part to the intake manifold 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting an exhaust gas pipe to an intake manifold in an exhaust gas recirculation system (hereinafter referred to as EGR) of an internal combustion engine.

[0002]

2. Description of the Related Art EGR is designed to eliminate pollution of exhaust gas from an internal combustion engine by introducing a part of the exhaust gas into the intake manifold. A part of the exhaust gas is exhausted from the exhaust pipe to the intake manifold. And is mixed with the intake air. The inflow position is a position where the air flow rate is large upstream of the branch of each cylinder of the intake manifold. An example of the connection structure of this portion is shown in FIG.

The intake manifold 11 is made of synthetic resin for the purpose of weight reduction and the like, and an exhaust gas pipe 14 made of a metal pipe is attached to the opening 12 through a connector 13. The connector 13 is made of metal such as stainless steel and is welded to the exhaust gas pipe 14. The connector 13 is attached to the intake manifold 11 by tightening nuts 15 and bolts 16 inserted in the intake manifold 11 via packings 17. It The exhaust gas flows into the inside 18 of the intake manifold 11 as shown by an arrow G and is mixed with the intake air (arrow A).

[0004]

[Problems to be Solved by the Invention] Arrow G
Exhaust gas flowing in like a high temperature (150 ℃ ~ 650
And the heat is transferred from the exhaust gas pipe 14 to the intake manifold 11 via the connector 13. Since the intake manifold 11 is made of synthetic resin and cannot withstand this heat, the portion to which the connector 13 is attached is thermally deformed, and a gap is created in the attachment portion, which causes looseness in the attachment, and air flows in through the gap to allow intake air. The amount changes and the engine output decreases. The connector 13 is provided with a bent portion 19 to radiate heat, but this is not sufficient.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a radiation fin is formed in a portion of an annular connector which is interposed between an exhaust gas pipe of an EGR and an intake manifold made of synthetic resin, in the vicinity of the exhaust gas pipe. Is arranged so as to face the intake air flow path inside the intake manifold.

[0006]

[Function] Exhaust gas flows in from the exhaust gas pipe and transfers heat to the connector, but since there is a radiation fin near the exhaust gas pipe of the connector and this is in contact with the intake air, the heat of the exhaust gas is the radiation fin. Emitted into the intake air. Therefore, the amount of heat transferred from the portion of the outer peripheral portion of the connector attached to the intake manifold is small, and the intake manifold is not thermally deformed.

[0007]

EXAMPLE FIG. 1 shows an example. An exhaust gas pipe 4 is attached to a wall surface opening 2 of a synthetic resin intake manifold 1 of an internal combustion engine with a connector 3 interposed therebetween. The opening 2 is provided at a position where the intake air (arrow A) flow rate is large on the upstream side where the intake manifold 1 branches into each cylinder. The base end of the exhaust gas pipe 4 is connected to an exhaust pipe (not shown) of the internal combustion engine, and the end portion is welded to the inner peripheral side of the connector 3. The outer peripheral side of the connector 3 is fastened to the peripheral edge of the opening 2 of the intake manifold 1 by an appropriate number of bolts 6.

The middle portion of the connector 3 is formed into a bent portion 7 having a cylindrical shape, and a plurality of parallel heat radiation fins 5 project annularly at a portion near the inner peripheral portion thereof and close to the exhaust gas pipe 4. Has been formed. The radiating fin 5 faces the intake air flow path (arrow A) inside the intake manifold 1.
The connector 3 is made of metal, and may be made of stainless steel together with the exhaust gas pipe 4, or may be made of aluminum, and the material is not limited. Further, as shown in FIG. 2, a plurality of vertical radiating fins 5a may be provided at right angles to the radiating fin 5 of FIG.

The connector 3 is fastened with a bolt 6 to an insert nut 8 embedded when the intake manifold 1 is molded, and the outer peripheral portion of the connector 3 is fixed via a packing 9.

Exhaust gas flows through the exhaust gas pipe 4 as indicated by arrow G, and is mixed with intake air (arrow A) in the air passage 10. The heat of the exhaust gas is transferred from the exhaust gas pipe 4 to the connector 3, but the heat radiation fins 5 or the heat radiation fins 5 and 5a radiate heat to the intake air, and the amount of heat transferred to the outer peripheral portion of the connector 3 is small, and the intake manifold 1 is connected. The parts are not deformed by heat.

[0011]

According to the EGR connection structure of the present invention, the heat of the exhaust gas is released into the intake air by the radiation fins provided in the connector, so that the amount of heat transferred from the connector to the synthetic resin intake manifold is small, Eliminates loose mounting and leaks due to the heat of the manifold.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a perspective view of a main part of another embodiment.

FIG. 3 is a sectional view of a conventional connection structure.

[Explanation of symbols]

 1 Intake manifold 3 Connector 4 Exhaust gas pipe 5 Radiating fin

Claims (1)

[Claims] 1. In a connection structure for connecting an exhaust gas pipe of an exhaust gas recirculation device for an internal combustion engine and an intake manifold made of synthetic resin with an annular connector interposed, heat is radiated to a portion near the exhaust gas pipe of the connector. Forming fins,
A connection structure for an exhaust gas recirculation device, characterized in that heat radiation fins are arranged so as to face the intake air flow path inside the intake manifold.