JP7619157B2 - Thermal management structure of V-engine - Google Patents

Description

The present invention relates to a thermal management structure for a V-type engine in which the exhaust system connected after the exhaust manifold is housed in the inner space of both banks.

Traditionally, in vehicles equipped with a V-type engine, the intake system or exhaust system is placed between the two banks to efficiently use the space in the engine compartment. Then, for soundproofing and to improve design, an engine cover is attached to cover the intake system or exhaust system. Because of this structure, heat tends to build up in the space inside the two banks, so technology has been devised to efficiently release that heat and prevent heat damage.

For example, in Patent Document 1, an intake system is placed between both banks of a V-type engine, and the engine cover is provided with an air intake port that takes in air from the fan and a heat insulator that blows the air that has been taken in to create an upward current. The upward current is then released through louvers provided on the top surface of the cover, and the hot air inside the bank is discharged from the louvers to the upper rear together with the generated upward current.

Japanese Patent Application Publication No. 10-331636

In the past, locating the exhaust system between the two banks of a V-engine tended to trap heat, so it was common to place the intake system between the two banks. However, in recent years, particularly in diesel engine vehicles, it has become necessary to keep the catalysts used in the exhaust gas purification system at the right temperature so that they can be activated and kept warm quickly, and efforts are underway to deliberately place these in the inner space between the two banks where heat is trapped.

In other words, by using exhaust heat, the catalyst can be effectively heated and kept warm from the moment the engine is started. However, placing the exhaust system equipment in the inner space of both banks, where heat tends to build up, naturally increases the risk of heat damage. Therefore, once the inner space has reached an appropriate temperature for the catalyst, proper heat management is required, which uses exhaust heat on the one hand, while at the same time preventing heat damage by having the exhaust system equipment dissipate heat so that the temperature of the inner space does not rise more than necessary.

In this regard, for example, in the structure of a V-engine such as that in Reference 1, the intake system is housed between the two banks, but if the exhaust system were to be housed between the two banks, there would be nothing to block the engine cover from the heat source (exhaust system), so there would be a high possibility of heat damage to the engine cover. In other words, hot air that passes through a relatively high-temperature heat source would hit the heat insulator and pass directly through the louvers of the engine cover. The engine cover is made of plastic, so there is a high risk of heat damage.

The present invention was conceived in light of these points, and aims to provide a thermal management structure for a V-engine that can suppress heat damage caused by the exhaust system devices housed in the inner spaces of both banks, while also efficiently dissipating heat from the devices.

To achieve the above object, the first aspect of the present invention is a thermal management structure for a V-type engine in which an exhaust system connected after the exhaust manifold of the V-type engine is housed in the inner space of both banks, and the thermal management structure for a V-type engine has an engine cover attached to cover the upper part of the inner space, and an insulator disposed between the engine cover and the exhaust system to block heat transfer from the exhaust system to the engine cover.

The second aspect of the present invention is a thermal management structure for a V-type engine according to the first aspect of the present invention, in which an opening is provided in a portion of the upper surface of the engine cover, and a portion of the insulator is exposed through the opening.

The third aspect of the present invention is a thermal management structure for a V-type engine according to the second aspect of the present invention, in which a portion of the insulator exposed from the opening has a slit whose longitudinal direction is perpendicular to the direction of travel of the vehicle when the V-type engine is mounted on the vehicle.

The fourth aspect of the present invention is a thermal management structure for a V-type engine according to the third aspect of the present invention, in which a plate-shaped louver extending in the longitudinal direction of the slit is provided on the long side of the slit facing the rear of the vehicle, and is inclined toward the front of the vehicle.

The fifth aspect of the present invention is a thermal management structure for a V-engine according to any one of the first to fourth aspects, in which the V-engine has a supercharger equipped with a turbine as the exhaust system device, and the insulator is arranged to cover at least the turbine.

The sixth aspect of the present invention is a thermal management structure for a V-engine according to any one of the first to fifth aspects, in which the engine cover is inclined so that the rear side of the vehicle is higher than the front side when the V-engine is mounted on the vehicle.

According to the first invention, the insulator is positioned between the engine cover and the exhaust system, so that the insulator is located in a position that directly receives heat emitted from the exhaust system, blocking the transfer of heat from the exhaust system to the engine cover. Furthermore, the insulator does not function to block (or change) the flow of air that enters the inner space between the two banks and flows between the exhaust system, such as the wind generated by running or the cooling wind generated by a cooling fan, and the exhaust system dissipates heat appropriately. Therefore, heat damage caused by the exhaust system contained in the inner space between the two banks is suppressed, and heat from the exhaust system can be efficiently dissipated.

According to the second invention, when the vehicle is running, the wind from the vehicle enters the inner spaces of both banks through the openings, mixing the air in the inner spaces of both banks, further promoting heat dissipation from the exhaust system. Also, when the engine is stopped, the hot air trapped in the inner spaces of both banks rises toward the engine cover, so the openings can function as an exhaust port for the rising hot air.

According to the third invention, when the vehicle is running, the wind from the vehicle enters the inner space of both banks through the openings and the slits in the insulator, and flows between the exhaust system devices located below the insulator, further promoting heat dissipation from the exhaust system devices. In addition, when the engine is stopped, the hot air trapped in the inner space of both banks rises toward the engine cover, so the slits and openings can function as an exhaust outlet for the rising hot air.

According to the fourth invention, the airflow hitting the inclined surface of the louver changes direction and passes through the slits, entering the inner space of both banks. This increases the amount of airflow flowing between the exhaust system devices located below the insulator, further promoting heat dissipation from the exhaust system devices.

According to the fifth invention, the turbocharger is usually set closer to the engine cover than other exhaust system devices, and the turbine is located upstream of the exhaust and is hot. Since an insulator is interposed between the turbocharger having such characteristics and the engine cover, heat damage to the engine cover can be prevented.

According to the sixth aspect of the invention, if the engine cover is not inclined, the area of the opening that appears when the engine cover is viewed from the direction of travel is zero, whereas if the engine cover is inclined, the area becomes larger. The increased area allows more wind to be drawn into the inner space of both banks, which further promotes heat dissipation from the exhaust system.

1 is a diagram showing a state in which a V-type engine according to an embodiment of the present invention is mounted on a vehicle. FIG. 1 is an exploded perspective view for explaining an overview of a V-type engine according to an embodiment of the present invention. FIG. FIG. 1 is a front view of a V-type engine according to an embodiment of the present invention. This is a cross-sectional view taken along line VV in FIG. FIG. 1 is a plan view of a V-type engine according to an embodiment of the present invention. 4 is a diagram for explaining the action and effect of the V-type engine according to the present embodiment when the vehicle is running. FIG. 4 is a diagram for explaining the operation and effect when the V-type engine according to the present embodiment is stopped. FIG.

● [V-type engine overview (Fig. 1 to 3)]
An embodiment for carrying out the present invention will be described below with reference to the drawings. First, an overview of a V-type engine 10 mounted on a vehicle 1 will be described with reference to Figs. 1 to 3. Note that when "front", "rear", "left", "right", "upper", and "lower" are shown in the drawings, "front" refers to the front direction of the vehicle 1, and "rear" refers to the rear direction of the vehicle 1. Also, "left" refers to the left direction of the vehicle 1, and "right" refers to the right direction of the vehicle 1. "Up" refers to the upper direction of the vehicle 1, and "lower" refers to the lower direction of the vehicle 1.

As shown in FIG. 1, the V-type engine 10 is mounted, for example, vertically in the engine room 2 of the vehicle 1. In other words, the rotating axis 11 of the crankshaft (not shown) housed in the crankcase 50 of the V-type engine 10 faces in the front-to-rear direction of the vehicle 1. In addition to the V-type engine 10, a radiator, cooling fan, battery, air cleaner, and other piping and wiring are also arranged in the engine room 2, but are not shown in FIG. 1.

As shown in FIG. 2, the V-engine 10 has a right bank 51 and a left bank 52 (corresponding to both banks) in which multiple cylinders are formed, and a predetermined bank angle is set for the right bank 51 and the left bank 52. An inner space 53 is formed between the right bank 51 and the left bank 52, and in order to effectively utilize the space in the engine room 2, the inner space 53 houses engine accessories. The engine accessories mainly house exhaust system devices, such as an exhaust gas purification device and a turbocharger equipped with a turbine as an exhaust system device. Note that in order to further effectively utilize the space, the inner space 53 may house part of the intake system device in addition to the exhaust system device.

As shown in FIG. 2, the engine cover 20 is attached so as to cover the upper part of the inner space 53. The engine cover 20 is made of, for example, resin, and has a predetermined design molded on its surface, improving the appearance when the user looks at the V-type engine 10 inside the engine room 2. In other words, unless the engine cover 20 is removed from the V-type engine 10, the engine accessories housed in the inner space 53 cannot be seen when the engine room 2 is opened, which is one of the factors that causes heat to build up in the inner space 53.

As shown in FIG. 2, the engine cover 20 has an opening 21 on a part of its upper surface. When the vehicle 1 is traveling, the wind 3 (see FIG. 1) enters the engine room 2 from the front grille (not shown), and the opening 21 serves as an inlet for directing the wind 3 into the inner space 53 of the V-engine 10. Also, if the V-engine 10 is stopped immediately after it becomes hot due to high-load operation without going through low-load operation such as idling (dead soak), the hot air generated by the exhaust system rises toward the engine cover 20, and the opening 21 also functions as an outlet for the rising hot air.

The insulators 30, 40 are disposed between the engine cover 20 and the exhaust system. The insulators 30, 40 are separate from each other, with the insulator 30 disposed on the front side of the inner space 53 and the insulator 30 disposed on the rear side of the inner space 53. In other words, the insulators 30, 40 are disposed below the engine cover 20, and the exhaust system is disposed further below the insulators 30, 40. The insulators 30, 40 are made of a metal such as aluminum, and block heat transferred from the exhaust system to the engine cover 20.

As shown in FIG. 3, the insulator 30 has slits 31a-31c and louvers 32a-32c. The longitudinal direction of the slits 31a-31c is perpendicular to the traveling direction (front-to-rear direction) of the vehicle 1, and, for example, three of them are formed in the insulator 30. The louvers 32a-32c are plate-shaped extending in the longitudinal direction of each slit 31a-31c, and are provided on the long side 33 of the slits 31a-31c on the rear side of the vehicle 1 so as to incline toward the front of the vehicle 1 (see FIG. 6).

● [Engine cover and insulator structure and features (Figs. 4 to 6)]
5 and 6, the engine cover 20 is provided with an opening 21 in front of the center. The engine cover 20 is also attached at an angle such that the rear side of the vehicle 1 is higher than the front side, and has a predetermined angle θ with respect to the horizontal plane. Therefore, as shown in Fig. 4, in a front view of the V-type engine 10 seen from the front of the vehicle 1, the upper surface of the engine cover 20 appears, and as a result, the opening 21 provided in the upper surface is also visible, making it easier for the running wind 3 to enter through the opening 21.

A portion of the insulator 30 is exposed from the opening 21 of the engine cover 20. The portion of the insulator 30 exposed from the opening 21 has slits 31a-31c and louvers 32a-32c. As described above, the louvers 32a-32c are inclined toward the front of the vehicle 1.

Here, in the case of a V-type engine 10, two turbochargers (twin turbo 61) are often provided. The turbocharger turbine is connected immediately downstream of the exhaust manifold, so it becomes particularly hot in the exhaust system. Therefore, if cooling by running wind 3 (see FIG. 1) is expected, it is better to place it closer to the opening 21. Also, since a predetermined bank angle is set for the right bank 51 and the left bank 52, the inner space 53 is a space that expands from the bottom to the top, so that the twin turbo 61 is necessarily accommodated up to the upper side of the inner space 53. As a result, the twin turbo 61 is closer to the engine cover 20. The insulator 30 is mainly attached to cover such a twin turbo 61 that is close to the bottom surface of the engine cover 20.

Meanwhile, the insulator 40 has its front end 41 overlapped with the rear end 34 of the insulator 30, and is attached at a greater distance from the engine cover 20 than the insulator 30, so as to cover mainly the exhaust gas purification device 62. Also, because the exhaust gas purification device 62 does not require as much storage space as the twin turbo 61 described above, the insulator 40 is attached so that it is further away from the engine cover 20 as it moves rearward. Note that the space secured between the insulator 40 and the engine cover 20 may be used to place an intake system device such as an intercooler.

[Functions and effects of the engine cover opening and the insulator slits and louvers (Fig. 7, Fig. 8)]
7, when the vehicle 1 is traveling, the traveling wind 3 enters the opening 21. At this time, the engine cover 20 is inclined by a predetermined angle θ, and the normal vector component of the traveling wind 3 with respect to the opening 21 (opening surface) increases, so that more traveling wind 3 can be taken in compared to when the engine cover 20 is not inclined (the normal vector component is 0).

The traveling wind 3 that enters the opening 21 then changes direction when it hits the inclined surfaces of the louvers 32a to 32c, passes through the slits 31a to 31c, and enters the inner space 53. In this way, by providing the louvers 32a to 32c, more traveling wind 3 can be guided into the inner space 53 compared to a structure in which only the slits 31a to 31c are provided.

The running wind 3 guided into the inner space 53 passes between the exhaust system (twin turbo 61, exhaust gas purification device 62) and the insulator 30, and reaches the rear end 34 of the insulator 30 while reducing the heat of the exhaust system. Then, it passes between the exhaust system and the insulator 40, and passes through the inner space 53 while similarly reducing the heat of the exhaust system.

As shown in FIG. 8, when the engine of the vehicle 1 is stopped, not only is there no wind 3 generated, but unless the vehicle is designed to turn on the cooling fan after the engine is stopped, no air flows between the exhaust system and the insulators 30, 40. Therefore, especially during dead soak, a large amount of heat is generated from the exhaust system. However, when the hot air trapped in the inner space 53 rises toward the engine cover, it flows along the underside of the insulator 40 toward the insulator 30, and is finally discharged from the slits 31a-31c and the opening 21.

The thermal management structure of the V-engine of the present invention is not limited to the appearance, configuration, structure, etc. described in this embodiment, and various modifications, additions, and deletions are possible without changing the gist of the present invention. For example, in this embodiment, three slits and three louvers are provided, but as long as they can guide the wind while driving into the inner space or release the hot air trapped in the inner space after the engine is stopped, the number of slits and louvers may be two or four, for example.

In addition, in this embodiment, the insulator 40 is provided separately from the insulator 30, but they may be integrated into one insulator. Conversely, the insulator 40 may be further divided into two or more insulators.

In addition, in this embodiment, the V-type engine is described as being mounted vertically in the engine room of the vehicle, but it may be mounted horizontally. In other words, even if the engine is mounted horizontally, if a slit is provided whose longitudinal direction is perpendicular to the vehicle's direction of travel, and if a plate-shaped louver extending in the longitudinal direction of the slit is provided so as to be inclined toward the front of the vehicle, the wind generated by the vehicle's movement can be guided into the internal space.

In addition, in this embodiment, two turbochargers (twin turbo) are provided, but it is also possible to provide one turbocharger.

Reference Signs List 1 Vehicle 2 Engine room 3 Traveling wind 10 V-type engine 11 Rotating shaft 20 Engine cover 21 Opening 30 Insulators 31a to 31c Slits 32a to 32c Louvers 33 Long side 34 Rear end 40 Insulator 41 Front end 50 Crankcase 51 Right bank 52 Left bank 53 Inner space 61 Twin turbo 62 Exhaust gas purification device θ Angle

Claims (5)

A thermal management structure for a V-type engine in which an exhaust system device connected to the exhaust manifold of the V-type engine is housed in the inner space of both banks,
An engine cover attached so as to cover an upper portion of the inner space;
an insulator disposed between the engine cover and the exhaust system to block heat transferred from the exhaust system to the engine cover;
having
an opening is provided in a part of an upper surface of the engine cover, and a part of the insulator is exposed through the opening;
Thermal management structure of a V-engine. 2. A thermal management structure for a V-type engine according to claim 1,
a slit having a longitudinal direction perpendicular to a traveling direction of the vehicle when the V-type engine is mounted on the vehicle is provided in a portion of the insulator exposed from the opening.
Thermal management structure of a V-engine. 3. A thermal management structure for a V-type engine according to claim 2,
A plate-shaped louver extending in the longitudinal direction of the slit is provided on a long side of the slit on the rear side of the vehicle so as to incline toward the front of the vehicle.
Thermal management structure of a V-engine. A thermal management structure for a V-type engine according to any one of claims 1 to 3,
the V-type engine has a turbocharger equipped with a turbine as the exhaust system device,
The insulator is disposed so as to cover at least the turbine.
Thermal management structure of a V-engine. A thermal management structure for a V-type engine according to any one of claims 1 to 4,
The engine cover is inclined so that the rear side of the vehicle is higher than the front side when the V-type engine is mounted on the vehicle.
Thermal management structure of a V-engine.

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