JP3009955B2 - Arrangement structure of engine exhaust system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrangement of an exhaust system of an engine, and more particularly, to an arrangement of a catalytic converter disposed immediately below an exhaust manifold.

[0002]

2. Description of the Related Art In many vehicles, a catalytic converter for purifying exhaust of an engine is provided in an exhaust system of the engine. In this type of catalytic converter, a so-called direct-coupled catalytic converter directly connected to an exhaust manifold is known (for example, Japanese Utility Model Application Laid-Open No. 64-13227, Japanese Utility Model Application Laid-Open No. 190924/1985, Japanese Patent Application Laid-Open No. 62-1987). 1
No. 06842).

In such a direct-coupled catalytic converter, the high-temperature exhaust gas discharged from the combustion chamber is introduced into the catalytic converter without lowering the temperature, so that the catalyst in the catalytic converter reaches the activation temperature early after the engine is started. Therefore, the catalytic converter can always exhibit a stable exhaust purification action. Since such a direct-coupled catalytic converter is disposed directly below the exhaust manifold, a supporting method of mounting the catalytic converter on a cylinder block side wall of the engine by a mounting bracket is generally adopted as a supporting method of the catalytic converter. In this support method, a pair of mounting brackets are respectively disposed on both sides of the catalytic converter, and one end of each mounting bracket is fixed to a flat cylinder block side wall, and the other end is fixed to each side edge or each side surface of the catalytic converter. You. In the thus supported catalytic converter, the rear surface of the catalytic converter faces the cylinder block side wall, and the front surface of the catalytic converter faces the radiator and the cooling fan located in front of the vehicle body of the engine.

[0004]

However, when such a catalytic converter is mounted on a horizontal engine, the catalytic converter is located between the engine and the cooling fan. For this reason, the ventilation of the radiator cooling fan toward the engine is blocked by the catalytic converter, and the cooling efficiency of the cooling fan decreases. Further, when the cooling fan operates during traveling of the vehicle, the outside air blown by the cooling fan hits the surface of the catalytic converter, and the catalytic converter is cooled. If the cooling fan continues to introduce outside air for a long period of time, the temperature of the catalyst in the catalytic converter drops below the activation temperature, and the catalyst can no longer exhibit a stable purifying action. Furthermore, recent radiator cooling fans tend to be located behind the radiator,
The cowling of the cooling fan and the side wall of the cylinder block of the horizontal engine are quite close. For this reason, it is becoming difficult to arrange the catalytic converter between the cooling fan and the cylinder block side wall.

Further, in the above-mentioned supporting method, the convex back surface of the curved catalytic converter is directed toward the relatively flat cylinder block side wall, so that both side edges or both side surfaces of the catalytic converter are separated from the cylinder block side wall. Resulting in. For this reason, both side edges or both side surfaces of the catalytic converter must be attached to the cylinder block side wall by a relatively long mounting bracket, and there is a problem in securing sufficient support rigidity of the catalytic converter.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exhaust system of a horizontal engine having a direct-coupled catalytic converter.
Prevents the catalytic converter from obstructing the ventilation of the cooling fan, prevents overcooling of the catalytic converter, and efficiently arranges the catalytic converter between the cooling fan located behind the radiator and the cylinder block side wall Is to do.

Another object of the present invention is to increase the support rigidity of the catalytic converter in an exhaust system of an engine having a direct-coupled catalytic converter.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention includes a catalytic converter disposed immediately below an exhaust manifold of a horizontal engine, the catalytic converter comprising a cooling fan for a radiator and the catalytic converter. An engine exhaust system having at least two fans, wherein the cooling fan is disposed behind a radiator, the catalytic converter being disposed between the rotation axis of each of the fans. The exhaust system of the engine is arranged in a region, the fans have different operation frequencies from each other, and the catalytic converter is positioned at a position biased to the fan with a lower operation frequency.

According to the above configuration of the present invention, the catalytic converter is positioned between each fan constituting the cooling fan. In the area between the fans, the amount of air blown by the fans is smaller than immediately behind each fan. Therefore, a large amount of air from each fan does not hit the catalytic converter, and the catalytic converter does not block the main airflow from each fan. In addition, since the cowling of each fan does not protrude greatly in the region between the fans, the catalytic converter can be efficiently disposed avoiding each cowling. Thus, the catalytic converter does not obstruct the cooling fan and the catalytic converter is not supercooled,
Moreover, the catalytic converter is efficiently disposed between the cooling fan disposed on the rear side of the radiator and the side wall of the cylinder block.

In an actual vehicle design, it may be difficult to accurately arrange a catalytic converter at the center of each fan.
In this case, it is preferable to arrange the catalytic converter at a position biased toward the fan whose operation frequency is relatively low. This allows
Obstruction of the air flow of the cooling fan and supercooling of the catalytic converter can be avoided as much as possible.

[0011] The present invention also provides the above-mentioned object.
A catalytic converter disposed immediately below an exhaust manifold of a horizontal engine, the catalytic converter being disposed between a radiator cooling fan and the engine, and the catalytic converter being mounted to a cylinder block of the engine by a mounting bracket. In the arrangement structure of the exhaust system of the engine, the cylinder block has a cone portion forming a connection portion with a transmission, and the catalytic converter is disposed near the cone portion with an axis extending vertically, and The convex curved surface forming the back surface of the converter is positioned so as to complement the curved concave side surface of the cone, and the mounting bracket has one end fixed to a side edge or side surface of the catalytic converter and the other end fixed to the cone. Engine exhaust system mounting structure fixed to the side of the engine To provide.

According to the above configuration of the present invention, the catalytic converter is supported by the so-called cone of the cylinder block. The cone is a strong cylinder block portion that forms a connection with the transmission, and has higher rigidity than other portions of the cylinder block. The cone also expands in a trumpet or arcuate manner toward the transmission so that a relatively narrow cylinder block body can be connected to a relatively large diameter transmission and has curved concave sides. The catalytic converter is arranged so that the curved convex backside is close to and along the side of the cone, so that the side edges or sides of the catalytic converter do not significantly separate from the side of the cone. Thus, using a relatively short length of mounting bracket to mount the cylinder block cone with relatively high strength,
The support rigidity of the catalytic converter can be increased.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1, 2, and 3 are a side view, a plan view, and a front view of a V-type engine having an exhaust system arrangement structure according to an embodiment of the present invention. FIGS. 1 to 3 show a horizontal type 6 disposed in an engine room of a vehicle.
A cylinder V-type engine 1 is shown. Only one bank 2 of the engine 1 located in front of the vehicle is shown,
An exhaust manifold 3 extends downward from the bank 2.
In front of the engine 1, a radiator 4 connected to a cooling water pipe of the engine 1, a condenser 6 connected to a refrigerant pipe of the air conditioner, and an electric cooling fan 5 for forced ventilation of the radiator 4 and the condenser 6 for the air conditioner Is arranged.

The cooling fan 5 has a first fan 5a for introducing outside air into the engine room via a front grill (not shown), a condenser 6 and a radiator 4, and a first fan 5a for introducing outside air via a front grill and a radiator 4. And two fans 5b. A fan control device (not shown) controls the operation of the first fan 5a and the second fan 5b. The fan control device activates the second fan 5b when the cooling water temperature of the engine 1 reaches a predetermined temperature, and increases the amount of air blown by the second fan 5b stepwise based on the cooling water temperature of the engine 1. The fan control device also operates the first fan 5a when the air conditioner operates. In this embodiment, since the first fan 5a is always operating when the air conditioner is operating, the operating frequency of the first fan 5a is higher than the operating frequency of the second fan 5b.

A transmission 8 is arranged beside the engine 1. The outer shape of the casing of the transmission 8 is partially illustrated in FIG. The end portion 7 of the cylinder block 1a connected to the transmission 8 is enlarged so as to correspond to the end profile of the transmission 8, and this end portion 7 is generally called a cone. Hereinafter, this end portion is referred to as a cone. The side surface of the cone 7 expands in an arc toward the transmission 8 as shown in FIG. 2, and the end of the cone 7 has an outer diameter substantially coinciding with the end of the transmission 8.

Referring to FIG. 1, a catalytic converter 10 is connected to a lower end of the exhaust manifold 3, and an exhaust pipe 9 is connected to a lower end of the catalytic converter 10. The catalytic converter 10 has a substantially cylindrical outer shape, and its axis extends vertically. The rear outer peripheral surface of the catalytic converter 10 is positioned close to the cone 7. Catalytic converter 10
Are extended in the vertical direction, and the convex back side surface of the catalytic converter 10 is complementary to the concave side surface of the cone 7, so that the catalytic converter 10 can be arranged as close as possible to the side surface of the cone 7.

In this embodiment, the catalytic converter 10 is supported on the cone 7 by the mounting bracket 11. As shown in FIGS. 2 and 3, the mounting bracket 11 is disposed between the outer peripheral surface of the catalytic converter 10 and the side surface of the cone 7,
One end is fixed to an outer peripheral surface of the catalytic converter 10 by a bolt 12, and the other end is fixed to a side surface of the cone 7 by a bolt 13. The outer peripheral surface of the catalytic converter 10 has a cone 7
Of the mounting bracket 11
Can be set to a relatively short length.

The cone 7 has a higher strength than other parts of the cylinder block 1a in order to maintain a firm connection between the cylinder block 1a and the transmission 8. Since the catalytic converter 10 is supported by the cone 7, the supporting rigidity of the catalytic converter 10 is sufficiently ensured. In this embodiment, the catalytic converter 10
Are located at positions where the main airflow of the cooling fan 5 does not directly hit. The catalytic converter 10 has the exhaust manifold 3
The exhaust gas discharged from the combustion chamber of the engine 1 passes through the catalytic converter 10 without lowering the temperature. Therefore, the temperature of the catalyst in the catalytic converter 10 rises to the activation temperature early after the start of the engine 1, so that the desired purifying action can be exhibited promptly after the start of the engine. However, when the cooling fan 5 is operated during traveling and the outside air is continuously introduced into the engine room, the catalytic converter 1
The catalyst within 0 is cooled to a temperature lower than the activation temperature, and it is difficult to exhibit a stable purifying action. When the catalytic converter 10 is located immediately behind the first or second fan 5a or 5b, the cooling fan 5
Blows the cooling fan 5 toward the engine 1 and deflects the blowing flow. Therefore, the cooling efficiency of the engine 1 by the cooling fan 5 decreases. For this reason,
In this example, the first fan 5a is positioned without positioning the catalytic converter 10 immediately behind the first fan 5a or the second fan 5b.
And in the region between the rotation axes of the second fan 5b, that is, in the intermediate region, whereby the supercooling of the catalytic converter 10 by the cooling fan 5 and the catalytic converter 10
This prevents the airflow from being hindered. Catalytic converter 1
0 is ideally located at the center between the first fan 5a and the second fan 5b.
It is difficult to accurately arrange the catalytic converter 10 at the center of the first and second fans 5a and 5b. Therefore, it is necessary to displace the catalytic converter 10 from the center of the first and second fans 5a and 5b to one of the fans 5 while keeping the temperature of the catalytic converter 10 in consideration. For this reason, in the present example, the catalytic converter 10 is positioned at a position slightly biased toward the second fan 5b having a relatively low operation frequency,
As a result, the catalytic converter 10 is switched to the first fan 5a as much as possible.
And an intermediate region of the second fan 5b to prevent the airflow and to prevent the catalytic converter 10 from being overcooled.

In the intermediate region, the first and the second
The cowlings 5c of the fans 5a and 5b do not protrude significantly. Therefore, the catalytic converter 10 having a convexly curved surface can be efficiently arranged behind the cooling fan 5. As described above, according to the present embodiment, the catalytic converter 10
Are supported by the horizontal engine 1 and arranged behind a cooling fan 5 located in front of the engine 1. Cooling fan 5
Is disposed behind the radiator 4 and has two fans having different operation frequencies, that is, first and second fans 5a and 5b. As described above, the catalytic converter 10 is positioned in the intermediate region between the first and second fans 5a and 5b, and the air blown by the cooling fan 5 does not hit the catalytic converter 10 in a large amount.
Further, the catalytic converter 10 does not block the main airflow of the cooling fan 5. Thus, according to the above arrangement, it is possible to prevent the catalytic converter 10 from being overcooled by the cooling fan 5 and to prevent the main airflow of the cooling fan 5 from being obstructed by the catalytic converter 10. Further, in the above embodiment, since the catalytic converter 10 is disposed at a position avoiding the cowlings 5c of the first and second fans 5a and 5b, the catalytic converter 10 is efficiently placed between the engine 1 and the cooling fan 5. Can be arranged in

Since it is difficult to accurately position the catalytic converter 10 at the intermediate position between the first and second fans 5a and 5b, the catalytic converter 10 is slightly displaced toward the second fan 5b which is relatively infrequently operated. Is located in the position.
Accordingly, the arrangement of the catalytic converter 10 can be appropriately adjusted to the actual arrangement in the engine room while the supercooling of the catalytic converter 10 and the obstruction of the main airflow by the catalytic converter 10 are prevented as much as possible.

Further, in the above embodiment, the catalytic converter 1
0 is disposed near the cone 7 of the cylinder block 1a, and the convex outer peripheral surface of the catalytic converter 10 is positioned close to the convex side surface of the cone 7. Thereby, the length of the mounting bracket 11 is set to a relatively short length, and the catalytic converter 10 is mounted on the cone 7 having a relatively high strength by the mounting bracket 11. Thus, sufficient support rigidity of the catalytic converter 10 is ensured.

[0022]

According to the above-mentioned structure of the present invention, in the arrangement structure of the exhaust system of the horizontal engine equipped with the direct-coupled catalytic converter, the catalytic converter is positioned in the intermediate area between the cooling fans. Prevents the catalytic converter from interfering with the ventilation of the cooling fan, prevents overcooling of the catalytic converter, and efficiently arranges the catalytic converter between the cooling fan located behind the radiator and the cylinder block side wall. It becomes possible.

According to the above structure of the present invention, in the arrangement structure of the exhaust system of the engine having the direct-coupled catalytic converter, the catalytic converter is vertically arranged near the cone of the cylinder block. By positioning the curved convex back surface so as to complement the concave side surface of the cone, fixing one end of the mounting bracket to the side edge or side surface of the catalytic converter, and fixing the other end to the side surface of the cone, Support rigidity can be increased.

[Brief description of the drawings]

FIG. 1 is a side view of a V-type engine provided with an exhaust system arrangement structure according to an embodiment of the present invention.

FIG. 2 is a plan view of the engine shown in FIG.

FIG. 3 is a front view of the engine shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 1a Cylinder block 2 Bank 3 Exhaust manifold 4 Radiator 5 Cooling fan 5a First fan 5b Second fan 6 Condenser 7 Cone 8 Transmission 9 Exhaust pipe 10 Catalytic converter 11 Mounting bracket 12 Bolt 13 Bolt

Continuation of the front page (72) Inventor Eiji Oda 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References: JP-A 47-33405 (JP, U) JP-A 4-116213 ( JP, U) Japanese Utility Model Showa 61-151027 (JP, U)

Claims (3)

(57) [Claims] The present invention further includes a catalytic converter disposed directly below an exhaust manifold of a horizontal engine, the catalytic converter being disposed between a radiator cooling fan and the engine, and the cooling fan being disposed behind a radiator. In an arrangement of an exhaust system of an engine having at least two fans provided, the catalytic converter is positioned in an intermediate region of a rotation axis of each fan, the fans have different operation frequencies from each other, and the catalytic converter is An arrangement for an exhaust system of an engine, wherein the exhaust system is positioned at a position biased toward a fan whose operation frequency is lower. A catalytic converter disposed immediately below an exhaust manifold of the horizontal engine, the catalytic converter being disposed between a radiator cooling fan and the engine, and the catalytic converter being mounted on the engine by a mounting bracket. In the arrangement structure of an exhaust system of an engine attached to a cylinder block, the cylinder block has a cone portion forming a connection portion with a transmission, and the catalytic converter is disposed near the cone portion with an axis line extending vertically. Arranged, the convex curved surface constituting the back surface of the catalytic converter is positioned so as to complement the curved concave side surface of the cone, and the mounting bracket has one end fixed to a side edge or a side surface of the catalytic converter, An engine exhaust characterized in that the other end is fixed to a side surface of the cone. The arrangement structure of the system. 3. A catalyzer comprising a catalytic converter disposed immediately below an exhaust manifold of a horizontal engine, wherein the catalytic converter is disposed between a radiator cooling fan and the engine, and the cooling fan is disposed on a rear side of the radiator. An engine exhaust system having at least two fans provided therein, wherein the catalytic converter is mounted on a cylinder block of the engine by a mounting bracket, wherein the catalytic converter has an intermediate region of a rotation axis of each fan. The cylinder block has a cone portion forming a connection portion with a transmission,
The catalytic converter is disposed in the vicinity of the cone portion with the axis line extending vertically, and the convex curved surface forming the back surface of the catalytic converter is positioned so as to be complementary to the curved concave side surface of the cone, and the mounting is performed. An arrangement for an exhaust system of an engine, wherein one end of a bracket is fixed to a side edge or a side surface of the catalytic converter, and the other end is fixed to a side surface of the cone.