JP6747762B2 - Internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine, and is characterized by a structure that protects a head portion from heat damage of an exhaust turbocharger.

It is widely practiced to provide an exhaust turbocharger in an internal combustion engine, but the housing portion of the exhaust turbocharger (particularly the turbine housing) becomes hot due to exhaust gas. Therefore, in order to prevent other members from being damaged by heat generated by the exhaust turbocharger, a heat shield plate (heat insulator) is provided.

As an example, Patent Document 1 discloses that a heat shield plate is fixed by using an oil pipe for lubricating a rotary shaft of an exhaust turbocharger, and the catalyst case is covered with the heat shield plate. ing. On the other hand, Patent Document 2 discloses that a turbine insulator is attached to a housing portion of an exhaust turbocharger.

JP, 2007-309124, A JP, 2016-180396, A

Now, as in Patent Document 1, a catalyst case is often connected to the exhaust turbocharger. Further, conventionally, as disclosed in Patent Document 1, the exhaust turbocharger has a lower-winding structure in which exhaust gas flows into a turbine chamber from above and flows downward, and therefore, a vertical internal combustion engine. In the case of an engine, the housing part of the exhaust turbocharger is roughly located next to the cylinder block, and thus the catalyst case is also located next to the cylinder block.

On the other hand, the size of the catalyst case tends to increase with the tightening of exhaust gas regulations, and if the height of the catalyst case is not increased, problems such as hindering the arrangement of the exhaust pipe may occur. It can be said that the exhaust turbocharger should have an upper winding structure in which exhaust gas flows from the bottom to the top in order to increase the height of the catalyst case. Then, the heat of the housing portion is directed toward the upper portion of the cylinder head and the head cover, so that the head cover and the cables arranged on the upper portion of the head portion are easily damaged by heat. In particular, if the head cover is made of resin, heat damage remarkably appears, and there is concern that the head cover may be deformed or deteriorated, or the ignition device may be adversely affected.

Regarding this point, it is conceivable to fix a heat shield plate (insulator) covering the housing part from the head cover side to the housing part of the exhaust turbo supercharger as in Patent Document 2, but the exhaust turbo supercharger The housing part is made of an expensive material (Niresist or cast stainless steel) because heat resistance is required. Therefore, if the boss part for the heat shield plate is provided, the material cost and processing cost increase. There is.

An object of the present invention is to improve such a current situation.

The present invention is
“Having a cylinder head and a head cover fixed to the upper surface of the cylinder head, a water-cooled exhaust turbocharger is attached to the exhaust side surface of the cylinder head directly or through an exhaust manifold,
The exhaust turbocharger includes an exhaust gas inflow portion attached to the cylinder head or the exhaust manifold, and a housing portion having a built-in rotary shaft driven by the exhaust gas inflowing from the exhaust gas inflow portion. The cooling water inflow pipe and the cooling water outflow pipe are connected to the housing portion at different heights ."
That is the basic configuration.

And in the above basic configuration,
"In the exhaust turbocharger, while the housing portion is arranged in an upper winding state in which the housing portion is higher than the exhaust gas inflow portion ,
In the cooling water inflow pipe and the cooling water outflow pipe, wraparound portions that are located between the housing portion and the cylinder head or the head cover and have a long posture in the crank axis direction are formed in different heights. A heat shield plate that suppresses heat transfer from the housing portion to the head cover or the cylinder head is provided in the wraparound portion of the cooling water inflow pipe and the cooling water outflow pipe, and extends over the wraparound portion of the cooling water inflow pipe and the cooling water outflow pipe. It is fixed in a raised state . "
It has the feature.

If you are connecting the catalyst case the exhaust turbocharger, the heat shield plate, interrupting a thermal shield plate and heat radiated from the top of the catalyst case, it is possible to protect the head cover and the cylinder head ..

According to the present invention, the heat shield can prevent or remarkably prevent the head cover, the cylinder head, the cable, and the like from being damaged by the heat due to the upper structure of the exhaust turbocharger. Since the heat shield plate is not fixed to the housing part of the exhaust turbocharger but to the pipe for cooling water, it is not necessary to perform special processing on the housing part made of an expensive material. No cost increase can be prevented.

Further, since the cooling water pipe can be bent into an arbitrary shape, the position of the heat shield plate can be set arbitrarily. Further, since the heat shield plate is cooled by the cooling water flowing through the cooling water, the heat shield effect can be improved as compared with the case where the heat shield plate is fixed to the housing portion. Further, since the vibration of the engine is transmitted to the heat shield plate by the cooling water pipe, the vibration of the heat shield plate can be suppressed.

Further, the heat shield plate for securing by straddled wants state and cooling water inlet pipe and a cooling water outlet pipe, to play a role of reinforcing plate heat shield plate connecting the cooling water inlet pipe and a cooling water outlet pipe As a result, vibration of the cooling water inflow pipe and the cooling water outflow pipe can be suppressed.

It is the side view which looked at an embodiment from the direction orthogonal to the crank axis and the cylinder bore axis. It is a II-II view of FIG.

(1). Basic Structure Next, an embodiment of the present invention will be described with reference to the drawings. The internal combustion engine has a cylinder block 1, a cylinder head 2 fixed to the upper surface thereof, and a head cover 3 fixed to the upper surface of the cylinder head 2. The cylinder head 2 is of a type in which an exhaust manifold portion is built in and one exhaust outlet 5 is opened on the exhaust side surface 4, and the exhaust turbocharger 6 is directly fixed to the exhaust side surface 4 of the cylinder head 2. ..

The turbocharger 6 has a housing portion 9 in which an exhaust gas inflow portion 7 fixed to the cylinder head 2 and a rotary shaft 8 (see FIG. 2) driven by the exhaust gas inflowing from the exhaust gas inflow portion 7 are incorporated. And have. The housing portion 9 is composed of a turbine housing 9a containing a turbine, a compressor housing 9b containing a compressor (not shown), and a bearing housing 9c positioned between the two. Although the housings 9a, 9b, 9c are separately configured and fixed, the turbine housing 9a and the bearing housing 9c can be integrated.

A turbine scroll passage 10 is formed in the turbine housing 9a, and as described above, a turbine (not shown) is rotatably held via the rotary shaft 8. Further, an exhaust gas outlet 11 through which exhaust gas is discharged is formed in the turbine housing 9 a so as to open in the axial direction of the rotary shaft 8, and a catalyst case 12 is connected to the exhaust gas outlet 11. Further, the wastegate passage portion 13 is formed in the turbine housing 9 a so as to bulge laterally (in the axial direction of the rotary shaft 8 ), and exhaust gas is discharged into the wastegate passage portion 13 through the exhaust gas outlet. A waste gate passage (not shown) for bypassing 11 is formed.

An intake inlet 14 opens in the compressor housing 9b in the axial direction of the rotary shaft 8, and the intake air flowing into the intake inlet 14 is pressurized in the compression scroll passage 15 and discharged from the intake outlet 16. Inside the bearing housing 9c, a semi-floating bearing that rotatably holds a rotating shaft (not shown) is formed. Therefore, the oil inflow pipe 17 is connected to the upper surface of the bearing housing 9c, and the oil discharge pipe 18 is connected to the lower surface of the bearing housing 9c.

A flange 19 for fixing to the cylinder head 2 is formed in the exhaust gas inflow portion 7 of the turbine housing 9a.

The turbocharger 6 has an upper winding structure in which the housing portion 9 (each of the housings 9a to 9c) is arranged at a position higher than the exhaust gas inflow portion 7. Therefore, the exhaust gas outlet 11 is also higher than the exhaust gas inflow portion 7, and the height of the catalyst case 12 is considerably higher than that of the conventional case. Therefore, even the catalyst case 12 having a long length to clear the strict regulation of the exhaust gas can be attached without causing any particular problem.

(2). Water-cooling structure/heat shield plate The turbocharger 6 is a water-cooling system in which a cooling water passage is formed in the bearing housing 9c, where the bearing housing 9c faces the cylinder head 2 side. The cooling water inflow pipe 20 and the cooling water outflow pipe 21 are connected to the back surface. The cooling water inflow pipe 20 is located below and the cooling water outflow pipe 21 is located above. Therefore, the cooling water flows from the bottom to the top in the cooling water passage of the bearing housing 9c.

Both the cooling water inflow pipe 20 and the cooling water outflow pipe 21 change their postures from the bearing housing 9c to the rear side and then to the upper side, and then take a long horizontal posture in the crank axis direction so as to face the exhaust gas inflow portion 7. Therefore, both pipes 20 and 21 have horizontal wraparound portions 20a and 21a located closer to the head cover 3 than the housing portion 9 is.

The wraparound portions 20a and 21a of the two pipes 20 and 21 have different heights such that the wraparound portion 21a of the cooling water inflow pipe 21 is located below and the wraparound portion 20a of the cooling water outflow pipe 20 is located above. A heat shield plate 22 in a state of straddling both of the recesses 20a and 21a is fixed by brazing to the back faces of the recesses 20a and 21a. The heat shield plate 22 has a height that covers the upper part of the cylinder head 2 and the entire head cover 3, and the length in the crank axis direction is the turbine housing 9a of the bearing housing 9c and the L-shaped joint portion 12a of the catalyst case 12. It has a length that covers and from behind. However, the size and shape of the heat shield plate 22 can be appropriately set as necessary. It is also possible to bend the upper part of the heat shield plate 22 toward the housing part 9.

As described above, since the heat shield plate 22 is arranged, the heat radiated from the turbocharger 6 and the heat radiated from the joint portion 12a of the catalyst case 12 reach the upper portion of the cylinder head 2 and the head cover 3. This can be significantly suppressed. Therefore, for example, even if the head cover 3 is made of resin, it is possible to prevent the head cover 3 from being deformed or deteriorated by heat. It can also protect cables and tubes.

Although the cooling water passage is provided in the bearing housing 9c in the above embodiment, the cooling water passage may be provided in the turbine housing 9a to cool the turbine housing 9a with water. In this case, the cooling water inflow pipe 20 and the cooling water outflow pipe 21 may be connected to the back surface of the turbine housing 9a. Since the turbocharger 6 is of the upper winding type, the rear surface of the turbocharger 6 faces the cylinder head 2 and the head cover 3, so that the cooling water inflow pipe 20 and the cooling water outflow pipe 21 are connected to the rear surface. If it becomes very easy.

The present invention can be variously embodied in addition to the above-described embodiments. For example, the cooling water inflow pipe is connected to the lower surface of the bearing housing or the turbine housing, the cooling water outflow pipe is connected to the upper surface of the bearing housing or the turbine housing, and both pipes are bent toward the cylinder head (or head cover) side. Can also be formed.

The present invention can be actually embodied in an internal combustion engine. Therefore, it can be used industrially.

1 Cylinder Block 2 Cylinder Head 3 Head Cover 4 Exhaust Side 5 Exhaust Outlet of Cylinder Head 6 Turbocharger 7 Exhaust Gas Inlet 8 Rotating Shaft 9 Housing 9a Part of Housing Turbine Housing 9b Part of Housing barrier compressor housing 9c bearing housing 10 turbine scroll passage 11 exhaust gas outlet 12 catalyst case 20 cooling water inlet pipe 20a coolant curved portion 22 of the curved portion 21 the cooling water outlet pipe 21a coolant outflow pipe of pipe forming part of the housing Hot plate

Claims (1)

It has a cylinder head and a head cover fixed to its upper surface, and on the exhaust side surface of the cylinder head, a water-cooled exhaust turbocharger is attached directly or via an exhaust manifold,
The exhaust turbocharger includes an exhaust gas inflow portion connected to the cylinder head or the exhaust manifold, and a housing portion having a built-in rotary shaft driven by the exhaust gas flowing from the exhaust gas inflow portion. In the housing portion, a cooling water inflow pipe and a cooling water outflow pipe are connected at different heights ,
The exhaust turbocharger, while the housing portion is arranged in a state of upper winding in a position higher than the exhaust gas inflow portion ,
In the cooling water inflow pipe and the cooling water outflow pipe, wraparound portions that are located between the housing portion and the cylinder head or the head cover and have a long posture in the crank axis direction are formed in different heights. A heat shield plate that suppresses heat transfer from the housing portion to the head cover or the cylinder head is provided in the wraparound portion of the cooling water inflow pipe and the cooling water outflow pipe, and extends over the wraparound portion of the cooling water inflow pipe and the cooling water outflow pipe. It is fixed in a raised state ,
Internal combustion engine.

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