JP7617868B2 - engine - Google Patents

Description

The present invention relates to an engine.

Conventionally, engines equipped with a turbocharger are known. In such engines, a cooling system is provided to prevent the temperature of the turbocharger from rising excessively. For example, Patent Document 1 discloses a configuration in which a cooling water flow path is provided in the turbine housing of the turbocharger.

JP 2017-186954 A

In a configuration in which a cooling water flow path is provided in the turbocharger, there are concerns that, for example, the structure of the turbocharger will become complicated and manufacturing costs will increase. There is a need for technology that can prevent the temperature of the turbocharger from rising excessively while preventing the engine structure from becoming complicated.

The present invention aims to provide a new technology that can prevent the turbocharger installed in an engine from becoming excessively hot.

An exemplary engine of the present invention is a liquid-cooled engine that includes an engine block consisting of a cylinder block and a cylinder head, an exhaust manifold attached to the engine block, a turbocharger driven by exhaust gas from the exhaust manifold, an exhaust connection pipe connecting the exhaust manifold and the turbocharger, and a cooling liquid flow path that flows the cooling liquid discharged from the engine block through the exhaust connection pipe and the exhaust manifold in that order.

According to the exemplary embodiment of the present invention, it is possible to prevent the turbocharger of the engine from becoming excessively hot.

FIG. 1 is a schematic perspective view showing the configuration of an engine. FIG. 2 is a schematic perspective view showing a portion of the engine that is composed of a cylinder block, a head block, and a head cover. Schematic cross-sectional view of a cylinder block portion of an engine. Schematic top view showing the engine configuration FIG. 2 is a diagram showing a schematic configuration of a coolant flow path provided in the engine; Schematic front view showing the engine configuration FIG. 2 is a schematic perspective view showing components that form a part of the cooling liquid flow path dedicated to the right cylinder bank and the left cylinder bank; FIG. 8 is a schematic cross-sectional perspective view showing a cross section taken along the line VIII-VIII shown in FIG. FIG. 2 is a schematic perspective view showing the configuration of a right exhaust pipe provided in the engine. FIG. 2 is a schematic perspective view showing the configuration of a gear case provided in the engine; FIG. 11 is a schematic perspective view of the gear case when viewed from a direction different from that of FIG. 10 . FIG. 1 is a schematic right side view showing the configuration of a gear case provided in an engine. FIG. 13 is a schematic cross-sectional perspective view showing a cross section taken along the line XIII-XIII shown in FIG. 12 . FIG. 13 is a schematic cross-sectional perspective view showing a cross section taken along the line XIV-XIV shown in FIG. 12 .

Below, an exemplary embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the following description, the X direction is the front-rear direction, the Y direction is the left-right direction, and the Z direction is the up-down direction. Note that the +X side is the front side and the -X side is the rear side. The +Y side is the right side, and the -Y side is the left side. The +Z side is the upper side, and the -Z side is the lower side. In detail, the direction in which the center line C of the crankshaft (output shaft) shown in FIG. 1 extends is the front-rear direction, and the side on which the flywheel 2 is arranged with respect to the cylinder block 1 is the rear side. In addition, the up-down direction is defined as the side on which the oil pan 3 is arranged with respect to the cylinder block 1 is the lower side. The direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction, and the side that is right when viewed from the rear toward the front is the right side, and the side that is left is the left side. Note that these directions are names used simply for explanation, and are not intended to limit the actual positional relationship and direction. In this specification, the crankshaft direction is the same as the front-to-rear direction in which the center line C of the crankshaft extends.

<1. Engine Overview>
Fig. 1 is a schematic perspective view showing a configuration of an engine 100 according to an embodiment of the present invention. The engine 100 is suitable as a marine engine for use in ships, for example. However, the engine 100 is not limited to being a marine engine and may be applied to other applications. The engine 100 is a diesel engine.

As shown in FIG. 1, engine 100 includes a cylinder block 1, a head block 4, and a head cover 5. Cylinder block 1 and head block 4 form an engine block (engine body). In other words, engine 100 includes an engine block. FIG. 2 is a schematic perspective view showing the portion of engine 100 that includes cylinder block 1, head block 4, and head cover 5. FIG. 3 is a schematic cross-sectional view of the cylinder block 1 portion of engine 100.

As shown in Figures 2 and 3, a crankshaft 6 and a piston 7 extending in the front-rear direction are arranged inside the cylinder block 1. The inside of the cylinder block 1 is connected to the inside of an oil pan 3 arranged below and storing lubricating oil. A flywheel 2 (see Figure 1) is attached to the rear end of the crankshaft 6. The flywheel 2 rotates integrally with the crankshaft 6 and is used to extract power from the engine 100. More specifically, the piston 7 is arranged inside a cylinder 11 formed in the cylinder block 1. The piston 7 is connected to the crankshaft 6 via a connecting rod 71.

In detail, the cylinder block 1 has a right cylinder 11R arranged on the right side and a left cylinder 11L arranged on the left side. When viewed from behind, the right cylinder 11R is cylindrical and extends diagonally, tilting to the right in the vertical direction. When viewed from behind, the left cylinder 11L is cylindrical and extends diagonally, tilting to the left in the vertical direction. The right cylinder 11R and the left cylinder 11L are arranged in a V shape. The pair of right cylinder 11R and left cylinder 11L arranged in a V shape are arranged with their cylinder axes slightly offset in the front-rear direction. In this embodiment, the left cylinder 11L is arranged slightly forward of the right cylinder 11R.

The cylinder block 1 has a right cylinder row 111R in which a plurality of right cylinders 11R are arranged in the front-rear direction, and a left cylinder row 111L in which a plurality of left cylinders 11L are arranged in the front-rear direction. That is, the engine 100 has two cylinder rows 111R, 111L. Each of the two cylinder rows 111R, 111L extends in the crankshaft direction. The two cylinder rows 111R, 111L are arranged side by side. In particular, the two cylinder rows 111R, 111L are arranged side by side in the left-right direction. The right cylinder row 111R and the left cylinder row 111L form a V-shaped bank. In this embodiment, the number of right cylinders 11R that constitute the right cylinder row 111R and the number of left cylinders 11L that constitute the left cylinder row 111L are both six, for example. That is, the engine 100 of this embodiment is a V-type 12-cylinder engine.

In each of the right cylinder row 111R and the left cylinder row 111L, a head block 4 is placed on top of each cylinder 11. The head block 4 is fastened to the cylinder block 1 using screws. In detail, the head block 4 includes a right head block 4R that is placed on top of the right cylinder 11R, and a left head block 4L that is placed on top of the left cylinder 11L. Since one right head block 4R is placed on each right cylinder 11R, there are as many right cylinders 11R as there are right cylinders 11R. Since one left head block 4L is placed on each left cylinder 11L, there are as many left cylinders 11L as there are left cylinders 11L. In this embodiment, the number of right head blocks 4R and left head blocks 4L is six.

Each head block 4 has an intake port 41 for supplying gas to a combustion chamber formed by the cylinder 11, piston 7, and head block 4, and an exhaust port (not shown) for exhausting gas from the combustion chamber. The exhaust port is provided on the side opposite to the side on which the intake port 41 is provided. In detail, the right head block 4R has an intake port 41 on the left side and an exhaust port on the right side. The left head block 4L has an intake port 41 on the right side and an exhaust port on the left side.

A head cover 5 is placed on top of each head block 4. The head cover 5 is fastened to the head block 4 using screws. Each head cover 5 covers the intake valves and exhaust valves (not shown) arranged on the head block 4. An injector 8 is attached to each head cover 5. One end of the injector 8, which is provided with an injection port for injecting fuel, faces the combustion chamber. The other end of the injector 8 protrudes from the head cover 5 toward the outside.

In detail, the head cover 5 includes a right head cover 5R that is placed over the right head block 4R, and a left head cover 5L that is placed over the left head block 4L. The right head covers 5R are placed over each right head block 4R, so there are the same number of right head covers 5R as there are right head blocks 4R. The left head covers 5L are placed over each left head block 4L, so there are the same number of left head blocks 4L. In this embodiment, the number of right head covers 5R and left head covers 5L is six. The number of right injectors 8R arranged on the right head cover 5R and the number of left injectors 8L arranged on the left head cover 5L are also six.

On the right side of the cylinder block 1, the right cylinder 11R, right head block 4R, and right head cover 5R that make up the right bank RB extend diagonally upward to the right. On the left side of the cylinder block 1, the left cylinder 11L, left head block 4L, and left head cover 5L that make up the left bank LB extend diagonally upward to the left. In a plan view from the front-to-rear direction, the right bank RB and the left bank LB are V-shaped, and the engine 100 has a V-bank. An intra-bank area 200 is formed between the right bank RB and the left bank LB in the left-right direction.

Returning to FIG. 1, the engine 100 is equipped with a top cover 9 and a side cover 10. The top cover 9 prevents water from splashing on the controller 26 (see FIG. 4, etc., described later) and other components disposed inside due to, for example, condensation. The side cover 10 prevents fuel from splashing due to, for example, cracks in components such as the head block 4. Although FIG. 1 only shows the side cover 10 disposed on the right side, a similar side cover 10 is also disposed on the left side. In other words, the engine 100 is equipped with a pair of left and right side covers 10.

Figure 4 is a schematic top view showing the configuration of an engine 100 according to an embodiment of the present invention. In Figure 4, the top cover 9 and the pair of side covers 10 are omitted. As shown in Figures 1 and 4, the engine 100 includes an intake manifold 21 and an exhaust manifold 22. The intake manifold 21 and the exhaust manifold 22 are attached to the engine block (specifically, the head block 4).

The intake manifold 21 distributes intake air, which is air or a mixture drawn in from the outside, to each cylinder 11. The intake manifold 21 is disposed on top of the engine 100 and extends in the front-to-rear direction. In detail, the intake manifold 21 includes a right intake manifold 21R for the right cylinder 11R and a left intake manifold 21L for the left cylinder 11L. That is, the engine 100 has two intake manifolds 21R, 21L.

The right intake manifold 21R is disposed above each intake port 41 (see FIG. 2) of the multiple right head blocks 4R aligned in the front-rear direction. The interior of the right intake manifold 21R is connected to each right cylinder 11R via each intake port 41. The left intake manifold 21L is disposed above each intake port 41 of the multiple left head blocks 4L aligned in the front-rear direction. The interior of the left intake manifold 21L is connected to each left cylinder 11L via each intake port 41.

In more detail, an intake valve (not shown) is provided between each intake port 41 and each cylinder 11, and when the intake valve is open, the inside of the intake manifold 21 communicates with the cylinder 11.

The exhaust manifold 22 collects the exhaust from each cylinder 11. The exhaust manifold 22 is disposed on the side of the engine 100 and extends in the front-to-rear direction. In detail, the exhaust manifold 22 includes a right exhaust manifold 22R for the right cylinder 11R and a left exhaust manifold 22L for the left cylinder 11L.

The right exhaust manifold 22R is disposed on the right side of multiple right head blocks 4R (see FIG. 2) arranged in the front-rear direction. The interior of the right exhaust manifold 22R and each right cylinder 11R are connected via exhaust ports (not shown) provided on the right side of the right head block 4R. The left exhaust manifold 22L is disposed on the left side of multiple left head blocks 4L (see FIG. 2) arranged in the front-rear direction. The interior of the left exhaust manifold 22L and each left cylinder 11L are connected via exhaust ports (not shown) provided on the left side of the left head block 4L.

In more detail, an exhaust valve (not shown) is provided between each exhaust port and each cylinder 11, and when the exhaust valve is open, the inside of the exhaust manifold 22 communicates with the cylinder 11.

The exhaust gas collected in the right exhaust manifold 22R is exhausted to the outside via the right supercharger 23R and the right exhaust outlet pipe 24R, both of which are located at the right rear of the engine 100. The exhaust gas collected in the left exhaust manifold 22L is exhausted to the outside via the left supercharger 23L and the left exhaust outlet pipe 24L, both of which are located at the left rear of the engine 100.

The right supercharger 23R and the left supercharger 23L each have a compressor section 231 and a turbine section 232. The compressor section 231 pressurizes and compresses intake air, such as air, supplied from outside the engine 100. The compressed intake air is supplied to the intake manifold 21 via the intercooler 25. The turbine section 232 is rotated by exhaust gas supplied from the exhaust manifold 22. The rotational power of the turbine section 232 is transmitted to the compressor section 231. That is, the right supercharger 23R and the left supercharger 23L of this embodiment are so-called turbochargers that use an exhaust gas turbine as a driving source. The engine 100 is equipped with a supercharger 23 driven by exhaust gas from the exhaust manifold 22.

The intercooler 25 connected to the intake manifold 21 is supplied with cooling water by a cooling water pump (not shown) and cools the intake air. The intake air supplied from the compressor section 231 is pressurized and compressed, generating compression heat and increasing the temperature. The intercooler 25 cools the intake air by exchanging heat between the cooling water supplied from the cooling water pump and the pressurized and compressed intake air. In other words, by providing the intercooler 25, the temperature of the intake air supplied to the intake manifold 21 can be adjusted to a desired temperature.

As shown in FIG. 4, the right intake manifold 21R and the left intake manifold 21L are arranged at a distance from each other in the left-right direction on the top of the engine 100. As shown in FIG. 4, when the top cover 9 is removed, the in-bank area 200 is exposed to the outside through the space between the right intake manifold 21R and the left intake manifold 21L. In the in-bank area 200, for example, a controller 26 that controls the entire engine 100, and a fuel pump 27 that supplies fuel to the injector 8 are arranged.

That is, the engine 100 includes a controller 26 disposed in an intra-bank area 200 located between the right cylinder row 111R and the left cylinder row 111L. The engine 100 also includes a fuel pump 27 disposed in the intra-bank area 200. Note that, strictly speaking, the intra-bank area 200 may be the spatial area between the right cylinder row 111R and the left cylinder row 111L. However, in this embodiment, the intra-bank area 200 broadly includes the spatial area in the left-right direction between the right bank RB including the right cylinder row 111R and the left bank LB including the left cylinder row 111L.

By arranging the controller 26 and the fuel pump 27 in the in-bank area 200, the in-bank area 200 can be used efficiently for arranging parts. This allows the engine 100 to be made more compact. However, the controller 26 and the fuel pump 27 may be arranged outside the in-bank area 200.

The controller 26 specifically includes a first controller 261 and a second controller 262. However, the number of controllers 26 may be changed as appropriate, and may be composed of only one controller, for example. In this embodiment, the first controller 261 and the second controller 262 are aligned in the front-rear direction (crankshaft direction). In detail, the first controller 261 is located forward of the second controller 262. One of the first controller 261 and the second controller 262 is the main controller, and the other is the sub-controller. In this embodiment, the first controller 261 is the main controller, and the second controller 262 is the sub-controller.

The first controller 261 configured as a main controller executes calculations necessary for controlling the engine 100. The calculations necessary for controlling the engine 100 include, for example, calculations related to the control of fuel injection and calculations related to stopping the engine 100. The second controller 262 configured as a sub-controller is connected to the first controller 261 by a communication line (not shown) and is provided so as to be able to communicate with the first controller 261. The second controller 262 performs control operations according to instructions from the first controller 261.

The first controller 261 controls the right injector 8R arranged in the right bank RB. That is, the first controller 261 and each right injector 8R are electrically connected. The second controller 262 controls the left injector 8L arranged in the left bank LB. That is, the second controller 262 and each left injector 8L are electrically connected.

Fuel pump 27 pressurizes the fuel and discharges it toward a high-pressure fuel pipe for the right bank RB (not shown) and a high-pressure fuel pipe for the left bank LB (not shown). Fuel passing through the high-pressure fuel pipe for the right bank RB is distributed to each right injector 8R arranged in the right bank RB. Fuel passing through the high-pressure fuel pipe for the left bank LB is distributed to each left injector 8L arranged in the left bank LB. Each injector 8 injects fuel into the combustion chamber under the control of controller 26.

<2. Cooling system>
The engine 100 of this embodiment is a liquid-cooled engine. The engine 100 includes a cylinder block 1 constituting an engine block, and a coolant flow passage 50 (see FIG. 5 described later) through which a coolant flows to cool each of a plurality of head blocks 4. In this embodiment, the coolant is cooling water. However, the coolant may be a liquid other than water, such as antifreeze. The antifreeze is, for example, a liquid obtained by mixing pure water and ethylene glycol in a predetermined ratio.

Figure 5 is a diagram showing a schematic configuration of the coolant flow path 50 provided in the engine 100 according to the embodiment of the present invention. In this embodiment, the coolant flow path 50 includes a first coolant flow path 50R and a second coolant flow path 50L. That is, the engine 100 includes the first coolant flow path 50R and the second coolant flow path 50L. The first coolant flow path 50R is provided for one of the two cylinder rows 111R and 111L. The second coolant flow path 50L is provided for the other of the two cylinder rows 111R and 111L. In detail, the first coolant flow path 50R is a coolant flow path provided for the right cylinder row 111R. The second coolant flow path 50L is a coolant flow path provided for the left cylinder row 111L.

The first coolant flow path 50R includes a coolant flow path 51R dedicated to the right cylinder row and a shared coolant flow path 52. The second coolant flow path 50L includes a coolant flow path 51L dedicated to the left cylinder row and a shared coolant flow path 52. The shared coolant flow path 52 is a coolant flow path shared by both the first coolant flow path 50R and the second coolant flow path 50L.

As shown in FIG. 5, the shared coolant flow path 52 includes a coolant pump 30, a coolant cooler 31, a lubricant cooler 32, and a thermostat case 34 that houses a thermostat 33. FIG. 6 is a schematic front view showing the configuration of an engine 100 according to an embodiment of the present invention. FIG. 6 is a view of the engine 100 viewed from the front to the rear. As shown in FIG. 6, the coolant pump 30, the coolant cooler 31, the lubricant cooler 32, and the thermostat case 34 are disposed at the front end of the engine 100.

The coolant pump 30 circulates the coolant through the coolant flow path 50. The coolant pump 30 is driven by rotational power transmitted from the crankshaft 6 via a gear (not shown). In this embodiment, the coolant pump 30 is a cooling water pump.

The coolant cooler 31 cools the coolant circulating through the coolant flow path 50. In this embodiment, the coolant cooler 31 is a fresh water cooler. The coolant cooler 31 cools the coolant circulating through the coolant flow path 50 by utilizing heat exchange with seawater pumped up by driving the seawater pump 35. The seawater pump 35 is disposed at the front end of the engine 100. The seawater pump 35 is driven by rotational power transmitted from the crankshaft 6 via a gear (not shown). In this embodiment, the seawater pumped up by the seawater pump 35 is sent to the intercooler 25, then reaches the coolant cooler 31, and is discharged to the outside (sea). In other words, the seawater pump 35 is an example of a cooling water pump that supplies cooling water to the intercooler 25 described above.

The lubricating oil cooler 32 cools the lubricating oil. The lubricating oil is supplied from the oil pan 3 to each part of the engine 100 by driving a lubricating oil pump (not shown) and returns to the oil pan 3. The lubricating oil cooler 32 also constitutes a flow path for the lubricating oil. The lubricating oil cooler 32 cools the lubricating oil using the cooling liquid flowing through the cooling liquid flow path 50. The lubricating oil pump is driven by the rotational power transmitted from the crankshaft 6 via a gear (not shown).

The thermostat case 34 covers the thermostat 33 placed in the coolant cooler 31 and forms the coolant flow path 50. The thermostat 33 has the function of maintaining the temperature of the coolant near a set temperature. Due to the function of the thermostat 33, the coolant that needs to be cooled is sent to the coolant cooler 31.

The coolant discharged from the coolant pump 30 is sent to the right cylinder row dedicated coolant flow path 51R and the left cylinder row dedicated coolant flow path 51L. The coolant that has passed through each of the right cylinder row dedicated coolant flow path 51R and the left cylinder row dedicated coolant flow path 51L is sent to the thermostat case 34 that houses the thermostat 33. The coolant sent to the thermostat case 34 includes coolant that is sent to the coolant cooler 31 by the action of the thermostat 33 and coolant that returns to the coolant pump 30 without being sent to the coolant cooler 31. The coolant sent to the coolant cooler 31 is cooled by the heat exchanger 311 (see FIG. 6) of the coolant cooler 31 and sent to the coolant tank 312 (see FIG. 6) of the coolant cooler 31. The coolant stored in the coolant tank 312 is sent to the coolant pump 30 as appropriate. In addition, a portion of the coolant sent to the coolant cooler 31 returns to the coolant pump 30 via the lubricant oil cooler 32.

Figure 7 is a schematic perspective view showing parts that make up part of the right cylinder row-only coolant flow path 51R and the left cylinder row-only coolant flow path 51L. In Figure 7, the open arrows indicate the flow of coolant. As shown in Figure 7, parts that make up the right cylinder row-only coolant flow path 51R include the right exhaust manifold 22R, the right coolant collecting pipe 28R, and the right exhaust connecting pipe 29R. Parts that make up the left cylinder row-only coolant flow path 51L include the left exhaust manifold 22L, the left coolant collecting pipe 28L, and the left exhaust connecting pipe 29L.

The right exhaust manifold 22R and the left exhaust manifold 22L are cylindrical and extend in the front-rear direction. FIG. 8 is a schematic cross-sectional perspective view showing a cross section cut at the VIII-VIII position shown in FIG. 7. In FIG. 8, the thick arrows indicate the flow of the coolant. As shown in FIG. 8, each of the right exhaust manifold 22R and the left exhaust manifold 22L has an internal exhaust pipe 222 that communicates with an exhaust gas inlet 221 provided on the inner side surface. Note that a plurality of exhaust gas inlets 221 are provided in each exhaust manifold 22R, 22L in a line in the front-rear direction, and each of them communicates with an exhaust port provided in each head block 4. In each of the right exhaust manifold 22R and the left exhaust manifold 22L, the coolant flows through the internal space SP1 of each exhaust manifold 22R, 22L. In detail, the coolant flows around the internal exhaust pipe 222 arranged in the internal space SP1.

The right cooling liquid collecting pipe 28R and the left cooling liquid collecting pipe 28L are cylindrical and extend in the front-rear direction. The right cooling liquid collecting pipe 28R is arranged alongside the right exhaust manifold 22R and is attached to the right exhaust manifold 22R. The right cooling liquid collecting pipe 28R is arranged diagonally above the right of the right exhaust manifold 22R. The left cooling liquid collecting pipe 28L is arranged alongside the left exhaust manifold 22L and is attached to the left exhaust manifold 22L. The left cooling liquid collecting pipe 28L is arranged diagonally above the left of the left exhaust manifold 22L.

A number of cooling liquid holes 281 are provided on the inner side of each of the right and left cooling liquid collecting pipes 28R and 28L. Each cooling liquid collecting pipe 28R, 28L has the same number of cooling liquid holes 281 as the number of cylinders that make up each cylinder row 111R, 111L, and are arranged at intervals in the front-to-rear direction. In this embodiment, the number of cooling liquid holes 281 provided in each cooling liquid collecting pipe 28R, 28L is six.

Each cooling liquid hole 281 is connected to a cooling liquid flow path provided in each head block 4 by a cooling liquid pipe (not shown). The cooling liquid discharged from the cooling liquid pipe connected to the cooling liquid flow path of each head block 4 constituting the right bank RB flows into the internal space SP2 of the right cooling liquid collecting pipe 28R through each cooling liquid hole 281. The cooling liquid discharged from the cooling liquid pipe connected to the cooling liquid flow path of each head block 4 constituting the left bank LB flows into the internal space SP2 of the left cooling liquid collecting pipe 28L through each cooling liquid hole 281.

As shown in FIG. 7, the right exhaust communication pipe 29R is connected to the rear end of the right exhaust manifold 22R. The left exhaust communication pipe 29L is connected to the rear end of the left exhaust manifold 22L. As shown in FIG. 1, the right exhaust communication pipe 29R is connected to the turbine section 232 of the right supercharger 23R. The left exhaust communication pipe 29L is connected to the turbine section 232 of the left supercharger 23L. In other words, the right exhaust communication pipe 29R connects the right exhaust manifold 22R and the right supercharger 23R. The left exhaust communication pipe 29L connects the left exhaust manifold 22L and the left supercharger 23L. That is, the engine 100 is provided with an exhaust communication pipe 29 that connects the exhaust manifold 22 and the supercharger 23.

Figure 9 is a schematic perspective view showing the configuration of the right exhaust communication pipe 29R equipped in the engine 100 according to an embodiment of the present invention. In Figure 9, the thick arrows indicate the flow of the coolant. The left exhaust communication pipe 29L has the same main configuration as the right exhaust communication pipe 29R. For this reason, the configuration of the exhaust communication pipe 29 will be explained using the right exhaust communication pipe 29R as a representative example.

As shown in FIG. 9, the right exhaust connecting pipe 29R has a space SP3 inside. An exhaust pipe 291 inside the connecting pipe, through which exhaust gas passes, is arranged in this internal space SP3. An exhaust inlet 292 that connects to one end of the exhaust pipe 291 inside the connecting pipe is provided on the front side of the right exhaust connecting pipe 29R. When the right exhaust connecting pipe 29R and the right exhaust manifold 22R are connected, the exhaust pipe 291 inside the connecting pipe and the exhaust pipe 222 inside the manifold are in communication.

The right exhaust communication pipe 29R is provided with an exhaust outlet 293 that is connected to the other end of the exhaust pipe 291 in the communication pipe. When the right exhaust communication pipe 29R is connected to the turbine section 232 of the right supercharger 23R, the exhaust pipe 291 in the communication pipe communicates with the inside of the turbine section 232. That is, exhaust gas from each combustion chamber of the right bank RB is sent to the turbine section 232 of the right supercharger 23R through the exhaust pipe 222 in the manifold of the right exhaust manifold 22R and the exhaust pipe 291 in the communication pipe of the right exhaust communication pipe 29R. Similarly, exhaust gas from each combustion chamber of the left bank LB is sent to the turbine section 232 of the left supercharger 23L through the exhaust pipe 222 in the manifold of the left exhaust manifold 22L and the exhaust pipe 291 in the communication pipe of the left exhaust communication pipe 29L.

As shown in FIG. 9, the right exhaust communication pipe 29R is provided with a cooling liquid inlet 294, which is an inlet for the cooling liquid. More specifically, the cooling liquid inlet 294 is provided on the right side surface of the right exhaust communication pipe 29R. However, the location where the cooling liquid inlet 294 is provided may be changed as appropriate. As shown in FIG. 7, the cooling liquid inlet 294 communicates with the internal space SP2 of the right cooling liquid collecting pipe 28R via the cooling liquid communication pipe 36. In addition, a cooling liquid outlet 295, which is an outlet for the cooling liquid, is provided on the front surface of the right exhaust communication pipe 29R. When the right exhaust communication pipe 29R and the right exhaust manifold 22R are connected, the cooling liquid outlet 295 communicates with the internal space SP1 of the right exhaust manifold 22R.

In the right exhaust connecting pipe 29R, the cooling liquid that enters the internal space SP3 from the cooling liquid inlet 294 flows around the exhaust pipe 291 inside the connecting pipe and is discharged from the cooling liquid outlet 295. Similarly, in the left exhaust connecting pipe 29L, the cooling liquid that enters the internal space SP3 from the cooling liquid inlet 294 flows around the exhaust pipe 291 inside the connecting pipe and is discharged from the cooling liquid outlet 295.

The coolant discharged from the coolant pump 30 and flowing through the coolant flow passage 51R for the right cylinder row is sent to the coolant flow passage for the right cylinder row 111R provided in the cylinder block 1 and each head block 4 that constitutes the right bank RB. As shown by the white arrows in Figure 7, the coolant discharged from each head block 4 that constitutes the right bank RB flows in the order of the right exhaust connection pipe 29R and the right exhaust manifold 22R.

The coolant discharged from the coolant pump 30 and flowing through the coolant flow passage 51L for the left cylinder row is sent to the coolant flow passage for the left cylinder row 111L provided in the cylinder block 1 and each head block 4 constituting the left bank LB. As shown by the white arrows in Figure 7, the coolant discharged from each head block 4 constituting the left bank LB flows in the order of the left exhaust connection pipe 29L and the left exhaust manifold 22L.

That is, in this embodiment, the engine 100 is provided with a coolant flow path 50 that flows the coolant discharged from the engine block through the exhaust connection pipe 29 and then the exhaust manifold 22. With this configuration, the engine block (cylinder block 1 and head block 4), which is an important part of the engine 100, can be cooled first with the coolant. Then, by sending the relatively low-temperature coolant discharged from the engine block to the exhaust connection pipe 29 first instead of the exhaust manifold 22, the part of the engine 100 in front of the supercharger 23, which is likely to become particularly hot, can be preferentially cooled. This makes it possible to appropriately suppress the temperature rise at the exhaust inlet part of the supercharger 23, and to suppress the temperature of the supercharger 23 from rising excessively.

In detail, the coolant discharged from each head block 4 constituting the right bank RB flows through the right coolant collecting pipe 28R, the right exhaust connecting pipe 29R, and the right exhaust manifold 22R in that order. Also, the coolant discharged from each head block 4 constituting the left bank LB flows through the left coolant collecting pipe 28L, the left exhaust connecting pipe 29L, and the left exhaust manifold 22L in that order. In other words, the coolant flow path 50 includes a coolant collecting pipe 28 that collects the coolant discharged from multiple points in the engine block and discharges it into the exhaust connecting pipe 29.

In this embodiment, the exhaust manifold 22 and the coolant collecting pipe 28 are arranged parallel to the crankshaft 6. In other words, the exhaust manifold 22 and the coolant collecting pipe 28 are arranged side by side with the crankshaft 6. In particular, the exhaust manifold 22 and the coolant collecting pipe 28 are arranged side by side with the crankshaft 6 in the left-right direction. More specifically, the right exhaust manifold 22R and the right coolant collecting pipe 28R are arranged side by side on the right side of the crankshaft 6. The left exhaust manifold 22L and the left coolant collecting pipe 28L are arranged side by side on the left side of the crankshaft 6.

At least a portion of the turbocharger 23 is disposed on one side of the exhaust manifold 22 in the crankshaft direction. In this example, the one side of the crankshaft direction refers to the rear side. In detail, at least a portion of the right turbocharger 23R is disposed rearward of the right exhaust manifold 22R and the right cooling liquid collecting pipe 28R. At least a portion of the left turbocharger 23L is disposed rearward of the left exhaust manifold 22L and the left cooling liquid collecting pipe 28L. By disposing in this manner, the structure connecting the exhaust connecting pipe 29 disposed near the turbocharger 23 to both the cooling liquid collecting pipe 28 and the exhaust manifold 22 can be configured without having a complex shape. In other words, the cooling liquid flow path through which the cooling liquid flows in the order of the cooling liquid collecting pipe 28, the exhaust connecting pipe 29, and the exhaust manifold 22 can be formed as a compact and simple structure.

At the other end of the crankshaft direction of the engine 100, coolant flow path components to which the coolant that has flowed through the exhaust manifold 22 is sent are disposed. In this example, the other end of the crankshaft direction refers to the front side. As shown by the white arrows in FIG. 7, the coolant that flows through the right exhaust manifold 22R and the left exhaust manifold 22L flows from the rear to the front. For this reason, by disposing the coolant flow path components at the rear end of the engine 100, the components that make up the engine 100 can be disposed efficiently.

The coolant flow path components may broadly include components that configure the coolant flow path. The coolant flow path components may include, for example, cooling pipes through which the coolant flows. The coolant flow path components are preferably components related to cooling the coolant. In detail, the coolant flow path components preferably include at least one of a thermostat case 34 that houses a thermostat 33 and a coolant cooler 31. The coolant discharged from the exhaust manifold 22 is hotter than when it is discharged from the coolant pump 30 after absorbing heat from exhaust gases, etc. For this reason, the coolant cooler 31 and the thermostat 33 used in conjunction with the coolant cooler 31 are configured to be located near where the coolant is discharged from the exhaust manifold 22, thereby effectively cooling the coolant to maintain cooling performance.

In this embodiment, the coolant cooler 31 is a fresh water cooler as described above, but it may be something other than a fresh water cooler, for example, a radiator. In other words, the category of coolant cooler may include fresh water coolers and radiators.

The first coolant flow path 50R includes a right coolant collecting pipe (first coolant collecting pipe) 28R that collects the coolant that has cooled one of the two cylinder rows 111R, 111L. The first coolant flow path 50R further includes a water-cooled right exhaust connecting pipe 29R that is connected to the right coolant collecting pipe 28R, and a water-cooled right exhaust manifold 22R that is connected to the right exhaust connecting pipe 29R. In detail, the right coolant collecting pipe 28R, the water-cooled right exhaust connecting pipe 29R, and the water-cooled right exhaust manifold 22R constitute a coolant flow path 51R dedicated to the right cylinder row.

The second coolant flow path 50L includes a left coolant collecting pipe (second coolant collecting pipe) 28L that collects the coolant that has cooled the other of the two cylinder rows 111R, 111L. The second coolant flow path 50L further includes a water-cooled left exhaust connecting pipe 29L that is connected to the left coolant collecting pipe 28L, and a water-cooled left exhaust manifold 22L that is connected to the left exhaust connecting pipe 29L. In detail, the left coolant collecting pipe 28L, the water-cooled left exhaust connecting pipe 29L, and the water-cooled left exhaust manifold 22L constitute a coolant flow path 51L dedicated to the left cylinder row.

In this embodiment, as shown in FIG. 7, the coolant discharged from the right exhaust manifold 22R flows into the coolant flow path provided in the gear case 40 via the cooling pipe 37. The coolant discharged from the left exhaust manifold 22L flows into the coolant flow path provided in the gear case 40 via the cooling pipe 37. That is, the engine 100 includes a gear case 40 in which a portion of the first coolant flow path 50R and a portion of the second coolant flow path 50L are provided. However, this is merely an example, and the gear case may be configured to include a portion of the first coolant flow path 50R and/or a portion of the second coolant flow path 50L.

The gear case 40 houses gears (not shown) that transmit the rotational power of the crankshaft 6 to the rotating shaft of the coolant pump 30, the seawater pump 35, the alternator (not shown), etc. That is, the configuration of this embodiment is a configuration in which the coolant flow paths 50 for the two cylinder rows 111R and 111L are formed using the gear case 40, which is an accessory part originally provided on the engine 100. Therefore, in the engine 100 having the two cylinder rows 111R and 111L, the coolant flow paths can be configured while suppressing an increase in the number of parts. Since the number of parts can be reduced, the space required for arranging the coolant flow paths can be reduced, making the engine 100 more compact.

In this embodiment, the coolant pump 30 and the seawater pump 35 are attached to the gear case 40. The gear case 40 is disposed forward of the two cylinder rows 111R and 111L. The gear case 40 is disposed forward of the engine block.

Figure 10 is a schematic perspective view showing the configuration of the gear case 40 provided in the engine 100 according to the embodiment of the present invention. Figure 11 is a schematic perspective view of the gear case 40 when viewed from a different direction than in Figure 10. Figure 10 is a view of the gear case 40 from the diagonal front right. Figure 11 is a view of the gear case 40 from the diagonal rear right. Figure 12 is a schematic right side view showing the configuration of the gear case 40 provided in the engine 100. Figure 13 is a schematic perspective cross-sectional view showing a cross section cut at position XIII-XIII shown in Figure 12. Figure 14 is a schematic perspective cross-sectional view showing a cross section cut at position XIV-XIV shown in Figure 12. Note that in Figures 10, 11, 13, and 14, thick arrows indicate the flow of coolant.

10 to 14, the gear case 40 is a plate-like member that has a thickness in the front-rear direction and extends in a direction perpendicular to the front-rear direction. In a plan view from the front-rear direction, the gear case 40 has a crankshaft hole 401 penetrating in the front-rear direction near the lower center. The front end of the crankshaft 6 is inserted into the crankshaft hole 401. The gear case 40 also has a bearing accommodating recess 402 in front of the crankshaft hole 401. The bearing accommodating recess 402 is recessed from the front to the rear and accommodates the bearing 38 (see FIG. 6) that rotatably supports the crankshaft 6. The gear case 40 also has a gear accommodating recess 403 on its rear surface that is recessed toward the front. The gear accommodating recess 403 accommodates multiple gears (not shown) that transmit the rotational power of the crankshaft 6. The multiple gears include, for example, a gear that transmits the rotational power to the coolant pump 30 and a gear that transmits the rotational power to the seawater pump 35. The gear case 40 also has a coolant pump mounting opening 404 on the front right side, where the coolant pump 30 is mounted. The gear case 40 also has a seawater pump mounting opening 405 on the front left side, where the seawater pump 35 is mounted.

The gear case 40 has a right side coolant inlet 406R at the top of the right side, which receives coolant from the right coolant collecting pipe 28R. The right side coolant inlet 406R is connected to a first case internal flow path 407R for the right cylinder row (see FIG. 13) provided inside the gear case 40. The first case internal flow path 407R for the right cylinder row is provided at the top of the gear case 40 and extends in the left-right direction. The first case internal flow path 407R for the right cylinder row is included in the first coolant flow path 50R, and more specifically, is included in the coolant flow path 51R dedicated to the right cylinder row.

The gear case 40 also has a left side coolant inlet 406L at the top of the left side, which receives coolant from the left coolant collecting pipe 28L. The left side coolant inlet 406L is connected to a first case internal flow passage 407L for the left cylinder row (see FIG. 13) provided inside the gear case 40. The first case internal flow passage 407L for the left cylinder row is provided at the top of the gear case 40, and is disposed to the left of the first case internal flow passage 407R for the right cylinder row. The first case internal flow passage 407L for the left cylinder row is included in the second coolant flow passage 50L, and more specifically, is included in the coolant flow passage 51L dedicated to the left cylinder row.

The first case internal flow path 407R for the right cylinder row and the first case internal flow path 407L for the left cylinder row are separated by a partition wall 408 extending in the vertical direction within the gear case 40. That is, the gear case 40 has a partition wall 408 that separates the first coolant flow path 50R and the second coolant flow path 50L. A difference in water pressure may occur between the coolant entering the case from the right side coolant inlet 406R and the coolant entering the case from the left side coolant inlet 406L. In such a case, if the partition wall 408 is not present, backflow due to the pressure difference may occur. By providing the partition wall 408, it is possible to prevent such backflow due to the pressure difference. In addition, if the cooling liquid entering the case from the right side cooling liquid inlet 406R and the cooling liquid entering the case from the left side cooling liquid inlet 406L both have sufficient pressure and flow downstream without backflow due to pressure difference, the partition 408 may not be provided, and the cooling liquid entering the case from the right side cooling liquid inlet 406R and the cooling liquid entering the case from the left side cooling liquid inlet 406L may be configured to merge inside the gear case 40.

The top surface of the gear case 40 is provided with a right upper surface coolant outlet 409R and a left upper surface coolant outlet 409L. The right upper surface coolant outlet 409R and the left upper surface coolant outlet 409L are arranged side by side on the left edge of the top surface of the gear case 40. The right upper surface coolant outlet 409R is arranged to the right of the left upper surface coolant outlet 409L. The right upper surface coolant outlet 409R is connected to the first case internal flow path 407R for the right cylinder row. The left upper surface coolant outlet 409L is connected to the first case internal flow path 407L for the left cylinder row.

The coolant that enters the first case flow passage 407R for the right cylinder row from the right side coolant inlet 406R is discharged from the case through the upper right side coolant outlet 409R and sent to the thermostat case 34. The coolant that enters the first case flow passage 407L for the left cylinder row from the left side coolant inlet 406L is discharged from the case through the upper left side coolant outlet 409L and sent to the thermostat case 34. That is, the coolant that enters the gear case 40 from the right coolant collecting pipe (first coolant collecting pipe) 28R and the left coolant collecting pipe (second coolant collecting pipe) 28L is discharged to the thermostat case 34 that houses the thermostat 33. However, this is an example, and the coolant that enters the gear case 40 from the right coolant collecting pipe 28R and/or the left coolant collecting pipe 28L may be discharged to the thermostat case 34 that houses the thermostat 33.

As shown in Figures 10 and 14, the gear case 40 has a first front cooling liquid inlet 410 on the right side of the upper front surface, which guides the cooling liquid discharged from the lubricant cooler 32 into the inside of the case. The gear case 40 has a common case internal flow path 411 connected to the first front cooling liquid inlet 410 inside. The common case internal flow path 411 is included in the common cooling liquid flow path 52. The gear case 40 has a front cooling liquid outlet 412 on the right end of the front surface, which is connected to the common case internal flow path 411. The front cooling liquid outlet 412 is located to the right and below the first front cooling liquid outlet 410. The cooling liquid that enters the common case internal flow path 411 from the first front cooling liquid inlet 410 is discharged outside the case from the front cooling liquid outlet 412 and sent to the cooling liquid pump 30.

As can be seen from the above, the gear case 40 has a shared coolant flow path 52 that is shared by both the first coolant flow path 50R and the second coolant flow path 50L. In detail, the gear case 40 has a portion of the shared coolant flow path 52. The shared coolant flow path 52 provided in the gear case 40 includes a flow path that guides the coolant discharged from the lubricant cooler 32, which cools the lubricant, to the coolant pump 30.

As shown in Figs. 10 and 14, the gear case 40 has a second front coolant inlet 413 at the center of the front surface, which guides the coolant discharged from the coolant pump 30 into the inside of the case. The gear case 40 has a branching section 414 inside, which is connected to the second front coolant inlet 413 and divides the coolant into the first coolant flow path 50R and the second coolant flow path 50L. The branching section 414 is included in the shared coolant flow path 52.

As shown in FIG. 14, the gear case 40 has a second case flow passage 415R for the right cylinder row that is connected to the branching portion 414 and extends diagonally downward to the right. The second case flow passage 415R for the right cylinder row is included in the first coolant flow passage 50R, and more specifically, is included in the coolant flow passage 51R dedicated to the right cylinder row. The gear case 40 also has a second case flow passage 415L for the left cylinder row that is connected to the branching portion 414 and extends diagonally downward to the left. The second case flow passage 415L for the left cylinder row is included in the second coolant flow passage 50L, and more specifically, is included in the coolant flow passage 51L dedicated to the left cylinder row.

As shown in FIG. 11, the gear case 40 has a right rear coolant outlet 416R at the right end of the lower rear surface, which is connected to the second case internal flow path 415R for the right cylinder row. The gear case 40 also has a left rear coolant outlet 416L at the left end of the lower rear surface, which is connected to the second case internal flow path 415L for the left cylinder row.

The cooling liquid discharged from the cooling liquid pump 30 is divided at the branching point 414 into cooling liquid flowing through the second case internal flow path 415R for the right cylinder row and cooling liquid flowing through the second case internal flow path 415L for the left cylinder row. The cooling liquid flowing through the second case internal flow path 415R for the right cylinder row is discharged outside the case from the right rear cooling liquid outlet 416R and sent to the cooling flow path for the right cylinder row provided in the cylinder block 1. The cooling liquid flowing through the second case internal flow path 415L for the left cylinder row is discharged outside the case from the left rear cooling liquid outlet 416L and sent to the cooling flow path for the left cylinder row provided in the cylinder block 1.

As can be seen from the above, a portion of the first coolant flow path 50R provided in the gear case 40 includes a flow path that guides the coolant supplied from the coolant pump 30 to one of the two cylinder rows 111R, 111L. Also, a portion of the second coolant flow path 50L provided in the gear case 40 includes a flow path that guides the coolant supplied from the coolant pump 30 to the other of the two cylinder rows 111R, 111L. In this example, one of the two cylinder rows 111R, 111L is the right cylinder row 111R. The other of the two cylinder rows 111R, 111L is the left cylinder row 111L.

In this embodiment, multiple types of flow paths for the flow of coolant are provided inside the gear case 40, allowing the coolant flow path 50 to be formed efficiently.

<3. Important points to note>
Various technical features disclosed in this specification can be modified in various ways without departing from the spirit of the technical creation. In other words, the above embodiment should be considered to be illustrative in all respects and not restrictive. In addition, multiple embodiments and modifications shown in this specification may be combined to the extent possible.

In the embodiment described above, the engine 100 is a V-engine, but this is merely an example. The present invention can also be applied to, for example, an in-line engine in which the pistons reciprocate vertically, or a horizontally opposed engine in which the pistons reciprocate horizontally.

1...Cylinder block (engine block)
4...Head block (engine block)
6: crankshaft 22: exhaust manifold 23: turbocharger 28: cooling liquid collecting pipe 29: exhaust connecting pipe 31: cooling liquid cooler (cooling liquid flow path component)
34... Thermostat case (coolant flow path component)
50: Coolant flow path 100: Engine

Claims (5)

A liquid-cooled engine,
An engine block including a cylinder block and a cylinder head;
an exhaust manifold attached to the engine block;
A turbocharger driven by exhaust gas from the exhaust manifold;
an exhaust communication pipe connecting the exhaust manifold and the turbocharger;
a coolant flow path through which the coolant discharged from the engine block flows through the exhaust connecting pipe and the exhaust manifold in this order;
Equipped with
The engine, wherein the turbocharger is disposed on one side of the exhaust manifold in a crankshaft direction . The engine of claim 1, wherein the coolant flow path includes a coolant collecting pipe that collects the coolant discharged from multiple locations in the engine block and discharges it to the exhaust connecting pipe. The engine of claim 2 , wherein the exhaust manifold and the coolant collecting pipe are disposed parallel to a crankshaft. The engine according to claim 3, wherein a coolant flow path component to which the coolant that has flowed through the exhaust manifold is sent is disposed at the other end in the crankshaft direction. The engine of claim 4, wherein the coolant flow path components include at least one of a thermostat case that houses a thermostat and a coolant cooler.