JPH094522A - Exhaust gas recirculation control device - Google Patents

Abstract

PURPOSE: To form an intake pipe out of a resin material by reducing the temperature of an exhaust gas recirculating to an intake system upto a level not exerting bad influence upon the intake pipe formed out of resin badly. CONSTITUTION: An EGR passage 2 is constituted so that an exhaust gas can be recirculated after the exhaust gas passes a catalytic converter 6 installed in the piping passage of the exhaust pipe 3. A heat radiation mechanism 4 is provided in the EGR passage 2. The piping passage of the EGR passage 2 is made so that the air blowing of the fan 5 for cooling a radiator for cooling the radiator 9 can be received.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation control device (hereinafter referred to as an EGR device) used in an internal combustion engine of an automobile.

[0002]

2. Description of the Related Art E used in a conventional automobile internal combustion engine
The GR device is generally provided with an exhaust gas recirculation passage that connects an intake system and an exhaust system of an engine, and a flow rate control valve is provided between the exhaust gas recirculation passages. The recirculated exhaust gas is
Recirculates to the intake system in a high temperature state.

An example of such an EGR device having a conventional mechanism is disclosed in JP-A-2-33459. This publicly known example is
By circulating the cooling water through the flow control valve, the flow control valve is cooled without lowering the temperature of the recirculated exhaust gas.

[0004]

However, in recent years, the weight of vehicles has been reduced in order to reduce the fuel consumption of automobiles, and the material forming the intake pipe is changed from the conventional metallic material to a resin material. There is a tendency. As a result, when hot recirculated exhaust gas flows into the intake pipe made of resin material,
A resin having a lower melting point than a metal material will be deformed or melted.

It is an object of the present invention to reduce the gas temperature before the recirculated exhaust gas flows into the intake pipe, until the resin can withstand it.

[0006]

In order to achieve the above object, the EGR device of the first invention has an EGR passage for guiding exhaust gas discharged from an exhaust system to an intake system, and exhaust gas of an internal combustion engine. In the EGR device that recirculates the
The EGR passage has a heat radiating mechanism for increasing the contact area with the atmosphere and a cooling water passage for circulating cooling water.
Device.

The EGR device of the second invention has an EGR passage for guiding the exhaust gas discharged from the exhaust system to the intake system, and in the EGR device for recirculating the exhaust gas of the internal combustion engine to the intake system, the EGR passage is , An EGR device which is piped to a position for receiving the air blown by the radiator cooling fan.

The EGR device of the third invention has an EGR passage for guiding the exhaust gas discharged from the exhaust system to the intake system, and in the EGR device for recirculating the exhaust gas of the internal combustion engine to the intake side, the EGR passage is , An EGR device in which exhaust gas is recirculated from the downstream of the catalytic converter.

[0009]

According to the EGR device of the first aspect of the present invention, when the exhaust gas passes through the EGR passage having the heat radiation mechanism and / or the cooling water passage for circulating the cooling water so that the contact area with the atmosphere becomes large, the gas temperature Is reduced to a level that does not affect the intake pipe made of resin such as deformation and melting.

In the EGR device of the second invention, when the exhaust gas passes through the EGR passage arranged at a position where the fan for cooling the radiator is blown, the gas temperature is transformed into an intake pipe formed of resin, melting, etc. To a level that does not affect.

The EGR device according to the third aspect of the present invention uses the EGR device for the exhaust gas whose exhaust gas temperature is lower than that downstream of the catalytic converter.
At the stage of flowing into the passage and flowing into the intake pipe made of resin, the gas temperature drops to a level at which the intake pipe is not deformed or melted.

[0012]

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

FIG. 1 shows an EG constructed in an internal combustion engine of an automobile.
2 shows an R device. The EGR device uses an EGR passage 2 to connect an exhaust pipe 3 provided for releasing exhaust gas generated by the operation of the internal combustion engine 1 to the atmosphere and an intake pipe 8 for sucking air required for the operation of the internal combustion engine 1 by an EGR passage 2. The flow rate of the exhaust gas communicating with each other and flowing through the EGR passage 2 is controlled by a flow control valve 7 provided in the middle of the EGR passage 2 and the intake pipe 8 to control NOx.
Reduce the invention of.

The EGR passage 2 is constructed so that exhaust gas is recirculated after passing through a catalytic converter 6 provided in a pipe path of the exhaust pipe 3. The exhaust gas extraction portion of the EGR passage 2 may be either the catalytic converter 6, the exhaust pipe 3 or the downstream flow of the catalytic converter.
Further, the EGR passage 2 is provided with a heat radiating mechanism 4 such as a fin so that the surface area in contact with the atmosphere is large compared to the passage length for the purpose of lowering the gas temperature of the circulating exhaust gas. In addition, in order to further improve the exhaust gas cooling effect, a cooling water passage 15 is provided to branch the cooling water for cooling the internal combustion engine 1 by the cooling water passage 15 and circulate the cooling water pipe in the exhaust gas recirculation passage. Things are possible. The cooling water passage 15 includes an indoor heater 13 and a heater water pipe 12.
It is configured so that it does not branch from the side, but branches from between the internal combustion engine-radiator cooling water passage 14 having a high cooling effect. Further, the piping path of the EGR passage 2 is arranged so as to receive the air blown by the radiator cooling fan 5 for cooling the radiator 9.

Regarding the heat radiation mechanism 4 provided in the EGR passage 2, FIG. 2 shows a first embodiment thereof, FIG. 3 shows a second embodiment thereof, FIG. 4 shows a third embodiment thereof, and FIG. FIG. 6 shows the fourth embodiment and the fifth embodiment.

In the embodiment shown in FIGS. 2 and 3, the radiation fin 10 is provided on the outer ring portion of the pipe to lower the temperature of the exhaust gas passing therethrough by the heat exchange action with the atmosphere. This radiation fin 10
Is formed on the whole or part of the EGR passage 2 by a machining method such as cutting, casting, or casting, or the heat radiation mechanism 4 having the radiation fins 10 formed by the above-described processing method is screwed or the like. It is possible to adopt a structure in which the passage 2 is fastened. The embodiment of FIG. 4 is an example in which a cooling water circulation passage 11 is provided in the heat dissipation mechanism 4 to achieve a heat dissipation effect. As the circulating cooling water, it is conceivable to use the cooling water used for cooling the internal combustion engine 1 in common. Cooling water circulation passage 1
1 shows that when the cooling water passage 11 is formed by cutting or casting in a part of the EGR passage, the passage is not closed by the heat dissipation mechanism 4 alone due to the processing of the cooling water passage,
A cooling water passage is formed by fastening the EGR passage 2 with a screw connection or the like. Further, as shown in FIG. 5, a cooling water passage is formed in advance with, for example, a steel pipe 16 or the like,
It is also possible to adopt a method of casting the steel pipe 16 forming the cooling water passage when the heat dissipation mechanism 4 is formed by casting. When the method of casting the cooling water passage formed in advance in this way is adopted, cooling water leakage can be prevented. FIG. 6 shows an example in which heat radiation to the atmosphere by the fins and cooling water circulation are shared.

[0017]

According to the present invention, the temperature of the exhaust gas recirculated to the intake system in the EGR device for recirculating the exhaust gas of the internal combustion engine to the intake side is at a level that does not adversely affect the intake pipe formed of resin. And the intake pipe can be made of a resin material.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an EGR passage formed in an internal combustion engine of an automobile according to the present invention.

FIG. 2 is a cross-sectional view showing a first embodiment of a heat dissipation mechanism provided in an EGR passage.

FIG. 3 is a cross-sectional view showing a second embodiment of a heat dissipation mechanism provided in the EGR passage.

FIG. 4 is a cross-sectional view showing a third embodiment of a heat dissipation mechanism provided in the EGR passage.

FIG. 5 is a sectional view showing a fourth embodiment of a heat dissipation mechanism provided in an EGR passage.

FIG. 6 is a cross-sectional view showing a fifth embodiment of a heat dissipation mechanism provided in the EGR passage.

[Explanation of symbols]

2 ... EGR passage, 4 ... Heat dissipation mechanism, 7 ... Flow control valve, 8 ...
Intake pipe, 10 ... Radiating fins, 11 ... Cooling water circulation passage.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F01P 5/06 511 F01P 5/06 511D

Claims (3)

[Claims] 1. An exhaust gas recirculation device for recirculating exhaust gas of an internal combustion engine to an intake side, the exhaust gas recirculation device having an exhaust gas recirculation passage for guiding exhaust gas discharged from an exhaust system to an intake system. The exhaust gas recirculation control device, wherein the circulation passage has a heat dissipation mechanism and / or a cooling water passage for circulating cooling water so that a contact area with the atmosphere is large. 2. An exhaust gas recirculation device for recirculating exhaust gas of an internal combustion engine to an intake side, the exhaust gas recirculation device having an exhaust gas recirculation passage for guiding exhaust gas discharged from an exhaust system to an intake system. An exhaust gas recirculation control device, characterized in that the circulation passage is arranged at a position for receiving the air blown by the radiator cooling fan. 3. An exhaust gas recirculation device for recirculating exhaust gas of an internal combustion engine to an intake side, the exhaust gas recirculation device having an exhaust gas recirculation passage for guiding exhaust gas discharged from an exhaust system to an intake system. An exhaust gas recirculation control device, wherein the circulation passage is arranged so as to recirculate exhaust gas from a downstream side of the catalytic converter.