JPH10317947A - Exhaust manifold with catalyst converter for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain heat radiation to the engine room of an automobile by fitting a catalyst converter to the outlet of an exhaust manifold, and providing water jackets mutually communicating to the outer circumference of the exhaust manifold and the catalyst converter. SOLUTION: A part of engine cooling water forcedly fed by a water pump flows from an inlet 19 on the front end of the gathering part 13 of an exhaust manifold 11 into a water jacket 17, and branches into a flow toward the water jacket 17 on the outer circumference of an outlet 14, and a flow flowing in a communication pipe 22 toward the water jackets 17A-17D of branched parts 12A 12D, and going to the water jacket 17 on the outer circumference of the outlet 14 through the communication pipe 22. Thereafter the two separated flows meet at the outlet 14, and the flow passes a connecting part 16 and flows in the water jacket 18 of a catalyst converter 15. The cooling water passed through the catalyst converter 15 while cooling it discharges from the outlet 20 of the catalyst converter 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for cooling an exhaust manifold with a catalytic converter of an internal combustion engine mounted on an automobile.

[0002]

2. Description of the Related Art Some engine rooms of an automobile are equipped with an internal combustion engine as shown in FIG. An exhaust manifold 2 is provided on a side surface of the cylinder head 1 of the internal combustion engine.
A small catalytic converter 3 is attached to the outlet of the exhaust manifold 2 (Japanese Utility Model Laid-Open No. 60-159823).

[0003] In an engine room having an internal combustion engine, the temperature of the exhaust manifold 2, the catalytic converter 3, the cylinder block, etc., whose surface temperature becomes 300 ° C or higher during operation of the engine, becomes high temperature. In particular, the temperature around the exhaust manifold 2 and the catalytic converter 3 is high. In order to prevent the components arranged in the vicinity from being damaged by the heat, a heat shielding cover 4 and a heat insulating cover 5 are usually provided near the exhaust manifold 2 and the catalytic converter 3 to cover them. Further, the heat shield cover 4 and the heat insulating cover 5 are air-cooled by the traveling wind of the automobile or the airflow of the radiator fan. Nevertheless, the heat generated from the exhaust manifold 2 and the catalytic converter 3 causes the vicinity thereof to have a considerably high temperature.

[0004]

However, recently, the inside of the engine room has been narrowed by various components, and it has been necessary to install an electronic control control box, rubber components, and the like in close proximity. Some of these components are vulnerable to heat, and the heat radiated from the exhaust manifold 2 and the catalytic converter 3 becomes high in temperature, so that the functions may be reduced or the components may become unusable. In order to prevent this, expensive heat-resistant materials were used for the control box and rubber parts, or a large-scale structure was modified to prevent this. Also, the same treatment was performed on the heat shielding cover 4 and the heat insulating cover 5.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an exhaust manifold with a catalytic converter that emits less heat to an engine room of an automobile.

[0006]

According to a first aspect of the present invention, in a structure in which a catalyst converter is attached to an outlet of an exhaust manifold, a water jacket communicating with each other is provided around the exhaust manifold and the catalytic converter, and cooling water is supplied to the water jacket. Circulated.

According to a second aspect of the present invention, there is provided a communication pipe for connecting water jackets in the vicinity of the connection of each branch of the exhaust manifold with the cylinder head.

According to a third aspect of the present invention, a cooling water inlet is provided in a water jacket of the exhaust manifold, and an outlet is provided in a water jacket of the catalytic converter, and a thermostat is provided at the outlet.

[0009]

According to the first aspect of the present invention, the outer circumference of the exhaust manifold and the catalytic converter is cooled with cooling water, and the degree of the inside of the engine room becoming hot due to the heat of the exhaust manifold and the catalytic converter is reduced.

In the second aspect of the present invention, the high temperature exhaust gas coming out of the cylinder head comes into contact first with the communication pipe connecting the water jackets near the junction of each branch portion of the exhaust manifold with the cylinder head. The branch portions that easily become high in temperature can be actively cooled, and the difference in cooling water temperature between the respective branch portions of the exhaust manifold is reduced.

In the third aspect, the catalyst temperature can be set to a temperature at which the conversion efficiency is good, and the exhaust gas composition can be controlled so as to always be good.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in further detail with reference to an embodiment of an exhaust manifold with a catalytic converter of a four-cylinder internal combustion engine shown in FIGS.

In FIG. 1, reference numeral 11 denotes an exhaust manifold, which is arranged in order from the front end of the internal combustion engine.
C and 12D are branch portions of the exhaust manifold 11. Each branch portion 12A, 12B, 12C, 12D is connected to an exhaust port of a cylinder head (not shown). 1
Reference numeral 3 denotes a collection portion of the exhaust manifold 11, and reference numeral 14 denotes an exhaust outlet of the exhaust manifold 11. Reference numeral 15 denotes a catalytic converter attached to the exhaust outlet 14 of the exhaust manifold 11. Reference numeral 16 denotes a flange joint-like connecting portion that connects the exhaust outlet 14 of the exhaust manifold 11 and the catalytic converter 15, and these connecting portions 16 can be separated from each other.
If necessary, the connecting portion 16 may be fixed with a connecting pipe interposed.

Reference numeral 17 denotes a branch portion 12 of the exhaust manifold 11.
Exhaust manifold 1 including A, 12B, 12C, 12D
1 Water jacket provided on the entire outer periphery. Also, 1
Reference numeral 8 denotes a water jacket provided on the outer periphery of the entire catalytic converter 15. The water jacket 17 and the water jacket 18 communicating with each other are formed by casting simultaneously at the same time when the exhaust manifold 11 and the catalytic converter 15 are formed. Reference numeral 19 denotes a cylindrical cooling water inlet provided in the water jacket 17 of the collecting portion 13 of the exhaust manifold 11 located at the front end of the internal combustion engine.
Numeral 0 is an outlet of a cylindrical cooling water provided in a water jacket 18 of the catalytic converter 15. The cooling water enters through the inlet 17 and flows through the exhaust manifold 11, the water jackets 17 and 18 of the catalytic converter 15, and the outlet. You are going to get out of 20. Therefore, as shown in FIG. 1, the water jacket 17 and the water jacket 18 communicate with each other at the connecting portion 16. 21 is exit 2
0 is a thermostat provided to open a passage when the temperature of the cooling water becomes equal to or higher than a predetermined value.

Reference numeral 22 denotes a branch portion 12 of the exhaust manifold 11.
This is a communication pipe that connects the water jackets 17A, 17B, 17C, and 17D around the outer circumferences of A, 12B, 12C, and 12D to be connected to the cylinder head. The communication pipe 22 is arranged in parallel with the water jacket 17 in the collecting portion 13 of the exhaust manifold, and is provided to divert the cooling water flowing from the inlet 19. High temperature exhaust gas coming out of the combustion chamber of the internal combustion engine through the cylinder head first comes into contact with the branch portion 12 which is likely to have a high temperature.
A, 12B, 12C, and 12D have a function of actively cooling the tip portions. Reference numerals 23A and 23B denote plate-shaped covers for closing the openings at the front end and the rear end of the collecting portion 13 of the exhaust manifold 11, respectively.

FIG. 2 is a sectional view taken along line AA of FIG. The cooling water inlet 19 is provided in the water jacket 17 of the collecting part 13 of the exhaust manifold 11 located at the front end of the internal combustion engine, and is provided in the water jacket 17 provided in the branch part 12A.
A extends to the vicinity of the junction of the branch portion 12A of the exhaust manifold 11 with the cylinder head, and communicates with the other water jackets 17B and C via the communication pipe 22 at that portion.

Next, the operation will be described.

A part of the engine cooling water is pressure-fed by a water pump (not shown) and led to the exhaust manifold 11. The cooling water flows into the water jacket 17 from an inlet 19 at the front end of the collecting portion 13 of the exhaust manifold 11. As shown in FIG.
The flow through the water jacket 17 of the collecting portion 13 of the exhaust manifold 11 toward the water jacket 17 on the outer periphery of the outlet 14 and the flow toward the water jackets 17A to 17D of the branch portions 12A to 12D to form the communication pipe 2
2 and flows into the water jacket 17 around the outlet 14 through the communication pipe 22. The flow through the communication pipe 22 is divided into the branch portions 12A, 12B, 12C, 12
The high-temperature exhaust gas coming out of the combustion chamber near the connection with the cylinder head of D through the cylinder head mainly comes into contact and cools mainly the part which tends to become high in temperature. A part of the flow of the divided cooling water flows on the way to the water jacket 17 at the outlet 14 of the exhaust manifold 11 and at the water jacket 17 at the branches 12B and 12C of the exhaust manifold 11. At that time, an action of reducing the mutual temperature difference is performed. Thereafter, the two streams merge at the outlet 14, pass through the connecting portion 16, and flow into the water jacket 18 of the catalytic converter 15. The cooling water that has passed while cooling the catalytic converter 15 flows to an outlet 20 provided in the catalytic converter 15. Thus, the outer circumference from the front end of the exhaust manifold 11 of the internal combustion engine to the rear end of the catalytic converter 15 is sufficiently cooled. In addition, since the thermostat 21 provided at the outlet 20 of the cooling water opens and closes according to the temperature, the flow rate of the cooling water passing through the outlet 20 is adjusted here. Then, the cooling water flowing out of the outlet 20 flows to a radiator or the like of the internal combustion engine, where heat is released.

The operation of the thermostat 21 controls the flow rate of the cooling water so as to be a large flow rate at a high temperature and a small flow rate at a low temperature, thereby controlling the exhaust gas temperature to optimize the catalyst conversion efficiency. Alternatively, it can be controlled so as to improve the catalyst life. Instead of the thermostat 21, the flow rate of the cooling water may be controlled by directly measuring the temperature of the cooling water in the water jacket or the exhaust temperature at the catalyst inlet. Further, although the engine coolant for the internal combustion engine is used as the coolant, a dedicated coolant circuit may be provided for the exhaust manifold and the catalytic converter. Further, the temperature of the internal combustion engine can be controlled by detecting the temperature of the cooling water in the water jacket and the temperature of the exhaust gas at the catalyst inlet to reduce the temperature, for example, when the temperature of the exhaust manifold and the catalytic converter is abnormally high. A port liner may be provided inside the exhaust manifold 11 to prevent excessive cooling near the exhaust port, or the heated cooling water may be effectively used for a heat exchanger for heating or hot water supply.

[0020]

According to the first aspect of the present invention, in a structure in which a catalytic converter is attached to an outlet of an exhaust manifold, a water jacket is provided integrally on the outer periphery of the exhaust manifold and the catalytic converter, and cooling water is circulated through the water jacket to exhaust gas. Since the manifold and the catalytic converter are cooled, the heat radiated from the exhaust manifold and the catalytic converter is reduced, and the temperature of the engine room becomes higher than before. Therefore, the electronic control box and rubber parts are not damaged by heat, and there is no need to use expensive heat-resistant materials or to improve the structure to a large scale. Also, it is not necessary to use expensive heat-resistant materials for the heat shield cover and the heat insulation cover.

According to the second aspect of the present invention, the communication pipes for connecting the water jackets near the junctions of the respective branch portions of the exhaust manifold and flowing cooling water are provided in parallel with the water jacket of the exhaust manifold. The high temperature exhaust gas coming out of the combustion chamber of the internal combustion engine via the cylinder head comes into contact first and can actively cool the branch which is likely to become high temperature, and also between the respective branches of the exhaust manifold. Cooling water temperature difference can be reduced. Further, even if the cooling water is likely to stagnate in the water jacket of the collecting portion, the cooling water can flow from the communication pipe, so that the cooling efficiency can be improved.

In the third aspect, the temperature of the cooling water is controlled by the thermostat, so that the catalyst temperature can be set to a temperature at which the conversion efficiency is good, so that the composition of the exhaust gas can always be controlled to be good.

[Brief description of the drawings]

FIG. 1 is a plan view including a partial cross section of an exhaust manifold showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an external view of the vicinity of an exhaust manifold of a conventional internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Exhaust manifold 3 Catalytic converter 4 Heat shield cover 5 Heat insulation cover 11 Exhaust manifold 12A Branch part 12B Branch part 13 Collecting part 14 Exhaust outlet of exhaust manifold 15 Catalyst converter 17 Water jacket 17A-17D Water jacket 18 Water jacket 19 Inlet 20 Exit 22 Communication pipe

Claims (3)

[Claims] 1. An internal combustion engine having a structure in which a catalytic converter is attached to an outlet of an exhaust manifold, a water jacket communicating with each other is provided on the outer periphery of the exhaust manifold and the catalytic converter, and cooling water is circulated through the water jacket. Exhaust manifold with catalytic converter. 2. The exhaust gas with a catalytic converter of an internal combustion engine according to claim 1, wherein a communication pipe is provided for connecting water jackets near the junction of each branch portion of the exhaust manifold with the cylinder head. Manifold. 3. The exhaust manifold according to claim 1, wherein a cooling water inlet is provided in a water jacket of the exhaust manifold, an outlet is provided in a water jacket of the catalytic converter, and a thermostat is interposed in the outlet. Exhaust manifold with catalytic converter for internal combustion engine.