JP7270087B2 - engine device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an engine device equipped with a supercharger.

Conventionally, in order to increase the air density in the cylinders of the engine, a turbocharger that compresses fresh air with exhaust energy is mounted on the engine device for the purpose of improving engine output and improving fuel efficiency (see Patent Document 1). . In a diesel engine, a large amount of high-density air is supplied to the cylinder to burn a large amount of fuel, which not only increases engine output and engine torque, but also promotes the mixing of fuel and air to prevent By suppressing mixed combustion, it is possible to reduce NOx emissions.

In addition, since a single-stage turbocharger with one turbocharger has a limit to the requirements of a high-power engine, a two-stage An engine equipped with a supercharger has been proposed (see Patent Document 2).

Japanese Patent No. 4517550 Japanese Patent No. 5237785

By the way, the mounting space for a diesel engine varies depending on the work vehicle (construction machinery, agricultural machinery, etc.) to be mounted, but in recent years, due to the demand for lighter and more compact, the mounting space is limited (narrow). many. Therefore, it is necessary to lay out the components of the diesel engine in a compact manner. In addition to the problem of limited mounting space, the cylinder head is required to have a highly rigid structure because parts such as an EGR device and a turbocharger are connected to and supported by the cylinder head.

Further, as in the engine device of Patent Document 2, when the turbochargers of the high pressure stage and the low pressure stage in the two-stage turbocharger are vertically arranged at positions separated from the exhaust manifold, the two-stage turbocharger is supported. The moment applied to the outlet of the exhaust manifold becomes large, and as a result, the supporting rigidity of the two-stage supercharger becomes low. Moreover, since the bypass route provided on the turbine side of the high-pressure stage is used as an external pipe, the pipe structure in the two-stage supercharger becomes complicated, and assembly to the engine device becomes complicated.

It is a technical object of the present invention to provide an engine device that has been improved in consideration of the above-mentioned current situation.

An engine device according to an aspect of the present application includes an exhaust manifold and an intake manifold arranged in a cylinder head, and a supercharger that compresses fresh air flowing into the intake manifold by fluid energy of exhaust gas discharged from the exhaust manifold. wherein the supercharger comprises a two-stage supercharger comprising a high-pressure supercharger connected to the exhaust manifold and a low-pressure supercharger connected to the high-pressure supercharger. The center of the low-pressure supercharger is arranged closer to the cylinder head than the center of the high-pressure supercharger in plan view.

It is a front view of an engine. It is a rear view of an engine. It is a left side view of an engine. It is a right side view of an engine. It is a top view of an engine. It is a bottom view of an engine. It is the perspective view which looked at the engine from diagonally forward. It is the perspective view which looked at the engine from diagonally back. Fig. 3 is an enlarged perspective view of the cylinder head viewed from the intake manifold side; Fig. 3 is an exploded perspective view of the cylinder head viewed from the exhaust manifold side; Fig. 3 is an exploded perspective view of the cylinder head viewed from the intake manifold side; It is a top view of a cylinder head. It is a front view of a cylinder head. It is a cross-sectional perspective view of a cylinder head and an EGR device. FIG. 4 is a cross-sectional perspective view of a cylinder head and an exhaust manifold; It is a cross-sectional perspective view of the connection part with an EGR cooler in a cylinder head. It is a cross-sectional perspective view of an EGR device. It is a top view of an EGR device. 1 is an exploded perspective view of an EGR device; FIG. FIG. 4 is an exploded view of a connecting portion with an EGR cooler in the cylinder head; FIG. 4 is a cross-sectional view of a connecting portion with an EGR cooler in the cylinder head; Fig. 3 is a left side view of the engine for explaining the arrangement of the two-stage supercharger; It is a rear enlarged view of an engine. It is a front enlarged view of an engine. It is a left view of a two-stage supercharger. It is a perspective view of a two-stage supercharger. It is a right side view of a two-stage supercharger. It is an exploded perspective view of a cooling water pump. It is a partial cross-sectional view of a cooling water pump attachment portion.

An embodiment embodying the present invention will be described below with reference to the drawings. First, the overall structure of a diesel engine (engine device) 1 will be described with reference to FIGS. 1 to 8. FIG. In the following description, both sides parallel to the crankshaft 5 (sides on both sides of the crankshaft 5) are referred to as left and right, the flywheel housing 7 installation side is referred to as the front side, and the cooling fan 9 installation side is referred to as the rear side. , are used as references for the four-way and top-bottom positional relationships in the diesel engine 1 for convenience.

As shown in FIGS. 1 to 8, an intake manifold 3 is arranged on one side of a diesel engine 1 parallel to a crankshaft 5, and an exhaust manifold 4 is arranged on the other side. In the embodiment, an intake manifold 3 is formed integrally with the cylinder head 2 on the right side of the cylinder head 2 and an exhaust manifold 4 is installed on the left side of the cylinder head 2 . The cylinder head 2 is mounted on a cylinder block 6 containing a crankshaft 5 and pistons (not shown).

Front and rear tip sides of the crankshaft 5 are projected from both front and rear sides of the cylinder block 6 . A flywheel housing 7 is fixed to one side of the diesel engine 1 that intersects with the crankshaft 5 (the front side of the cylinder block 6 in the embodiment). A flywheel 8 is arranged in the flywheel housing 7 . The flywheel 8 is pivotally supported on the front end side of the crankshaft 5 and configured to rotate integrally with the crankshaft 5 . It is configured to take out the power of the diesel engine 1 through the flywheel 8 to the working part of the working machine (for example, hydraulic excavator, forklift, etc.). A cooling fan 9 is provided on the other side of the diesel engine 1 intersecting the crankshaft 5 (in the embodiment, on the rear side of the cylinder block 6). It is configured to transmit rotational force from the rear end side of the crankshaft 5 to the cooling fan 9 via the V-belt 10 .

An oil pan 11 is arranged on the lower surface of the cylinder block 6 . Lubricating oil is stored in the oil pan 11 . The lubricating oil in the oil pan 11 is sucked by an oil pump (not shown) arranged on the right side surface of the cylinder block 6 at the connecting portion of the cylinder block 6 with the flywheel housing 7 . It is supplied to each lubricating part of the diesel engine 1 via an oil cooler 13 and an oil filter 14 arranged on the right side. The lubricating oil supplied to each lubricating section is then returned to the oil pan 11 . An oil pump (not shown) is configured to be driven by rotation of the crankshaft 5 .

A fuel supply pump 15 for supplying fuel is attached to the connecting portion of the cylinder block 6 with the flywheel housing 7 , and the fuel supply pump 15 is arranged below the EGR device 24 . A common rail 16 is fixed to the side surface of the cylinder block 6 below the intake manifold 3 of the cylinder head 2 and arranged above the fuel supply pump 15 . On the upper surface of the cylinder head 2 covered with the head cover 18, there are provided injectors (not shown) for four cylinders having electromagnetic open/close control type fuel injection valves.

Each injector is connected via a fuel supply pump 15 and a cylindrical common rail 16 to a fuel tank (not shown) mounted on the work vehicle. Fuel in the fuel tank is pressure-fed from the fuel supply pump 15 to the common rail 16, and the common rail 16 stores high-pressure fuel. High-pressure fuel in the common rail 16 is injected from each injector into each cylinder of the diesel engine 1 by controlling the opening and closing of the fuel injection valve of each injector.

A blow-by gas reducing device for taking in blow-by gas leaking from the combustion chamber of the diesel engine 1 to the upper surface of the cylinder head 2 is placed on the upper surface of the head cover 18 covering intake valves and exhaust valves (not shown) provided on the upper surface of the cylinder head 2. 19 are provided. A blow-by gas outlet of the blow-by gas reducing device 19 communicates with an intake portion of the two-stage turbocharger 30 via a reducing hose 68 . The blow-by gas from which the lubricating oil component has been removed in the blow-by gas reducing device 19 is returned to the intake manifold 3 via the two-stage supercharger 30 .

An engine starter 20 is attached to the flywheel housing 7 and arranged below the exhaust manifold 4 . The engine starting starter 20 is attached to the flywheel housing 7 at a position below the connecting portion between the cylinder block 6 and the flywheel housing 7 .

A cooling water pump 21 for cooling water lubrication is arranged below the cooling fan 9 at a portion on the left side of the rear surface of the cylinder block 6 . As the crankshaft 5 rotates, the cooling fan 9 and the cooling water pump 21 are driven via the cooling fan drive V-belt 10 . Cooling water in a radiator (not shown) mounted on the work vehicle is supplied to the cooling water pump 21 by driving the cooling water pump 21 . Cooling water is supplied to the cylinder head 2 and the cylinder block 6 to cool the diesel engine 1 .

The cooling water pump 21 is arranged below the exhaust manifold 4 , and the cooling water inlet pipe 22 communicating with the cooling water outlet of the radiator is located on the left side of the cylinder block 6 at the same height as the cooling water pump 21 . is fixed to On the other hand, a cooling water outlet pipe 23 communicating with the cooling water inlet of the radiator is fixed above the rear surface of the cylinder head 2 . The cylinder head 2 has a cooling water drainage portion 35 projecting rearward of the intake manifold 3 , and the cooling water outlet pipe 23 is installed on the upper surface of the cooling water drainage portion 35 .

The inlet side of the intake manifold 3 is connected to an air cleaner (not shown) via a collector (EGR body case) 25 of an EGR device 24 (exhaust gas recirculation device), which will be described later. Fresh air (outside air) sucked into the air cleaner is dust-removed and purified by the air cleaner, sent to the intake manifold 3 through the collector 25, and then supplied to each cylinder of the diesel engine 1. In the embodiment, the collector 25 of the EGR device 24 is connected to the right side of the intake manifold 3 that is formed integrally with the cylinder head 2 and constitutes the right side surface of the cylinder head 2 . That is, the outlet opening of the collector 25 of the EGR device 24 is connected to the inlet opening of the intake manifold 3 provided on the right side surface of the cylinder head 2 . In this embodiment, the collector 25 of the EGR device 24 is connected to an air cleaner via an intercooler (not shown) and a two-stage supercharger 30, as will be described later.

The EGR device 24 has a collector 25 as a relay pipe that mixes recirculated exhaust gas (EGR gas from the exhaust manifold 4) of the diesel engine 1 and fresh air (external air from the air cleaner) and supplies the mixture to the intake manifold 3. , an intake throttle member 26 that communicates the collector 25 with the air cleaner, a recirculation exhaust gas pipe 28 that is a part of a recirculation pipe connected to the exhaust manifold 4 via an EGR cooler 27, and the recirculation exhaust gas pipe 28. and an EGR valve member 29 that communicates with the collector 25 .

The EGR device 24 is arranged on the right side of the intake manifold 3 in the cylinder head 2 . That is, the EGR device 24 is fixed to the right side surface of the cylinder head 2 and communicates with the intake manifold 3 inside the cylinder head 2 . In the EGR device 24, the collector 25 is connected to the intake manifold 3 on the right side of the cylinder head 2, and the EGR gas inlet of the recirculation exhaust gas pipe 28 is connected to the front portion of the intake manifold 3 on the right side of the cylinder head 2 and fixed. be. An EGR valve member 29 and an intake throttle member 26 are connected to the front and rear of the collector 25, respectively, and an EGR gas outlet of a recirculation exhaust gas pipe 28 is connected to the rear end of the EGR valve member 29.

The EGR cooler 27 is fixed to the front side surface of the cylinder head 2 , and the cooling water and EGR gas flowing inside the cylinder head 2 flow into and out of the EGR cooler 27 , and the EGR gas is cooled in the EGR cooler 27 . EGR cooler connection bases 33 and 34 for connecting the EGR cooler 27 project from the front side surface of the cylinder head 2 at left and right positions, and the EGR cooler 27 is connected to the connection bases 33 and 34 . That is, the EGR cooler 27 is arranged above the flywheel housing 7 and in front of the cylinder head 2 so that the rear end surface of the EGR cooler 27 and the front side surface of the cylinder head 2 are separated from each other.

A two-stage supercharger 30 is arranged on the side of the exhaust manifold 4 (left side in the embodiment). The two-stage supercharger 30 includes a high pressure supercharger 51 and a low pressure supercharger 52 . The high-pressure supercharger 51 has a high-pressure turbine 53 with a built-in turbine wheel (not shown) and a high-pressure compressor 54 with a built-in blower wheel (not shown), and the low-pressure supercharger 52 has a turbine wheel (not shown). and a low pressure compressor 56 containing a blower wheel (not shown).

An exhaust inlet 57 of a high pressure turbine 53 is connected to the exhaust manifold 4, an exhaust inlet 60 of a low pressure turbine 55 is connected to an exhaust outlet 58 of the high pressure turbine 53 via a high pressure exhaust gas pipe 59, and an exhaust outlet 61 of the low pressure turbine 55 is connected. The ends of exhaust gas discharge pipes (not shown) on the exhaust gas intake side are connected. On the other hand, the fresh air supply side (fresh air outlet side) of an air cleaner (not shown) is connected to the fresh air intake (fresh air inlet) 63 of the low pressure compressor 56 via an air supply pipe 62, and the low pressure compressor 56 is supplied with fresh air. A fresh air intake port 66 of the high pressure compressor 54 is connected to a port (fresh air outlet) 64 via a low pressure fresh air passage pipe 65, and an interface is connected to a fresh air supply port 67 of the high pressure compressor 54 via a high pressure fresh air passage pipe 71. Connect the fresh air intake side of the cooler (not shown).

A high-pressure supercharger 51 is connected to an exhaust outlet 58 of the exhaust manifold 4 and fixed to the left side of the exhaust manifold 4 , while a low-pressure supercharger 52 is connected via a high-pressure exhaust gas pipe 59 and a low-pressure fresh air passage pipe 65 . is connected to the high-pressure supercharger 51 and fixed above the exhaust manifold 4 . That is, the high-pressure supercharger 51 with a small diameter and the exhaust manifold 4 are arranged side by side below the low-pressure supercharger 52 with a large diameter, so that the two-stage supercharger 30 is positioned on the left side of the exhaust manifold 4. and are arranged to surround the upper surface. That is, the exhaust manifold 4 and the two-stage turbocharger 30 are compactly fixed to the left side surface of the cylinder head 2 so as to be arranged in a rectangular shape when viewed from the rear (front view).

Next, the configuration of the cylinder head 2 will be described below with reference to FIGS. 9 to 16. FIG. As shown in FIGS. 9 to 16, the cylinder head 2 has a plurality of intake passages 36 for introducing fresh air into a plurality of intake ports (not shown) and a plurality of exhaust passages for leading exhaust gas from the plurality of exhaust ports. 37 are formed. An intake manifold 3 that collects a plurality of intake passages 36 is integrally formed on the right side of the cylinder head 2 . By forming the cylinder head 2 and the intake manifold 3 integrally, it is possible to improve the gas sealing performance from the intake manifold 3 to the intake passage 36 and increase the rigidity of the cylinder head 2 .

The cylinder head 2 has an exhaust manifold 4 connected to the left side opposite to the right side where the intake manifold 3 is formed, and an EGR cooler 27 connected to the front side (flywheel housing 7 side) adjacent to the left and right sides. be done. Connection pedestals (EGR cooler connection pedestals) 33 and 34 that are connected to the EGR cooler 27 are formed so as to protrude from the front side surface of the cylinder head 2, and EGR gas flow paths (EGR gas relay flow paths) are formed in the connection pedestals 33 and 34. 31, 32 and cooling water flow paths (cooling water relay flow paths) 38, 39 are formed.

By forming the EGR gas relay passages 31, 32 and the cooling water passages 38, 39 in the connecting pedestals 33, 34 to which the EGR cooler 27 is connected, the cooling water piping and the EGR No gas piping is required. Therefore, it is possible not only to ensure the sealing performance at the connection part with the EGR cooler 27 without being affected by expansion and contraction of the piping due to EGR gas and cooling water, but also to withstand external fluctuation factors such as heat and vibration (structural stability). performance) can be improved, and the configuration can be made compact.

The cylinder head 2 has an upstream EGR gas relay passage 31 that communicates from the front portion of the left side surface to the front side surface. is in communication with In addition, the cylinder head 2 includes a downstream EGR gas relay passage 32 that communicates from the front portion of the right side surface (in front of the intake manifold 3) to the front side surface, and the EGR gas inlet of the recirculation exhaust gas pipe 28 is connected to the downstream side EGR gas passage. It communicates with the gas relay channel 32 . The cylinder head 2 has EGR cooler connection pedestals 33 and 34 projecting forward from both left and right edge sides (front left corner portion and front right corner portion of the cylinder head 2) of the front side surface thereof. An upstream EGR gas relay passage 31 is provided in the connecting seat 33 , and a downstream EGR gas relay passage 32 is provided in the connecting seat 34 .

An EGR device 24 is connected to an intake manifold 3 projecting from the right side surface of the cylinder head 2 . The intake manifold 3 is provided on the rear side of the right side of the cylinder head 2 (toward the cooling fan 9), and is configured by protruding rightward from the lower side of the right side of the cylinder head 2. It has an intake inlet 40 . An intake outlet 83 of the collector 25 of the EGR device 24 is connected to an intake inlet 40 of the intake manifold 3 projecting from the right side of the cylinder head 2 , and the EGR device 24 is fixed on the right side of the cylinder head 2 .

In front of the right side surface of the cylinder head 2 (on the side of the flywheel housing 7), a connection base 34 connected to the EGR cooler 27 is projected forward. of the EGR gas outlet is open. One end of the recirculated exhaust gas pipe 28 of the EGR device 24 is connected to the right side surface of the connecting base 34, so that the collector 25 of the EGR device 24 is connected via the recirculated exhaust gas pipe 28 and the EGR valve member 29. It communicates with the downstream EGR gas relay passage 32 in the cylinder head 2 .

Behind the right side surface of the cylinder head 2 (on the side of the cooling fan 9), a cooling water drain (thermostat case) 35 whose upper surface is open and communicates with the cooling water outlet pipe (thermostat cover) 23 is provided so as to protrude rearward. A thermostat (not shown) is installed inside. Since the cooling water drainage portion 35 is configured to be offset behind the right side surface of the cylinder head 2, the V-belt 10 wound around the fan pulley 9a to which the cooling fan 9 is fixed is positioned below the cooling water drainage portion 35. and the length of the diesel engine 1 in the longitudinal direction can be shortened. The cooling water drainage part 35 also protrudes from the right side surface of the cylinder head 2 , and the intake manifold 3 and the cooling water drainage part 35 are arranged side by side in the front-rear direction on the right side surface of the cylinder head 2 .

A connection base 33 connected to the EGR cooler 27 is projected forward in front of the left side surface of the cylinder head 2 (on the flywheel housing 7 side). of the EGR gas inlet 96 is open. That is, on the left side surface of the cylinder head 2, the EGR gas inlet 96 of the upstream EGR gas relay passage 31 and the exhaust outlets of the plurality of exhaust passages 37 are opened side by side in the front-rear direction. On the other hand, the exhaust manifold 4 has an EGR gas outlet 41 that communicates with the upstream EGR gas relay passage 31 and an exhaust inlet that communicates with the plurality of exhaust passages 37 on the right side surface that is connected to the left side surface of the cylinder head 2 . 42 are arranged side by side in the front-rear direction and open. Therefore, since the EGR inlet and the exhaust outlet are provided side by side on the same surface of the cylinder head 2, the connecting portion between the cylinder head 2 and the exhaust manifold 4 can be easily airtight (gas-tight) by sandwiching one gasket 45 therebetween. sealing property) can be ensured.

An exhaust collecting portion 43 communicating with the EGR gas outlet 41 and the exhaust inlet 42 is provided in the exhaust manifold 4 so that the longitudinal direction is the longitudinal direction. An exhaust outlet 44 communicating with the collecting portion 43 is opened. In the exhaust manifold 4, when the exhaust gas from the exhaust passage 37 of the cylinder head 2 flows into the exhaust collecting portion 43 through the exhaust inlet 42, part of the exhaust gas becomes EGR gas, and the EGR gas outlet 41 is upstream of the cylinder head 2. The exhaust gas flows into the side EGR gas relay passage 31 , and the rest of the exhaust gas flows into the two-stage supercharger 30 from the exhaust outlet 44 .

A pair of left and right EGR cooler connection pedestals 33 and 34 are provided on the front side surface of the cylinder head 2 on the exhaust manifold 4 side and the intake manifold 3 side, respectively. The EGR cooler connection base 33 is provided with an upstream EGR gas relay passage 31 that allows the EGR gas passages of the exhaust manifold 4 and the EGR cooler 27 to communicate with each other. On the other hand, the EGR cooler connection pedestal 34 is provided with a downstream EGR gas relay passage 32 that allows the EGR gas passages of the EGR device 24 and the EGR cooler 27 to communicate with each other. Further, the EGR cooler connection base 33 is provided with a downstream cooling water flow path 38 through which the cooling water is discharged from the EGR cooler 27 . On the other hand, the EGR cooler connection pedestal 34 is provided with an upstream cooling water flow path 39 for supplying cooling water to the EGR device 24 and the EGR cooler 27 .

Since the EGR cooler connection pedestals 33 and 34 are configured to protrude, the EGR gas piping that communicates the exhaust manifold 4, the EGR cooler 27, and the EGR device 24 with each other becomes unnecessary, and the number of connection points in the EGR gas flow path is reduced. less. Therefore, in the diesel engine 1 intended to reduce NOx due to EGR gas, not only EGR gas leakage can be reduced, but also deformation due to stress change due to expansion and contraction of piping can be suppressed. Further, since the EGR gas relay passages 31, 32 and the cooling water passages 38, 39 are formed in the EGR cooler connection pedestals 33, 34, the shape of each passage 31, 32, 38, 39 formed in the cylinder head 2 is simplified, the cylinder head 2 can be easily cast without using complicated cores.

Since the EGR cooler connecting seat 33 on the intake manifold 3 side and the EGR cooler connecting seat 34 on the exhaust manifold 4 side are separated from each other, the mutual influence of thermal deformation of the connecting seats 33 and 34 can be suppressed. Therefore, it is possible not only to prevent gas leakage and breakage at the connecting portions between the EGR cooler connection bases 33 and 34 and the EGR cooler 27 but also to maintain the rigidity balance of the cylinder head 2 . Further, since the volume of the front side surface of the cylinder head 2 can be reduced, the weight of the cylinder head 2 can be reduced. Furthermore, since the EGR cooler 27 can be arranged away from the front side surface of the cylinder head 2 and can be configured to have a space in front of and behind the EGR cooler 27, cooling air can flow around the EGR cooler 27. The cooling efficiency in can be improved.

A downstream side cooling water flow path 38 and an upstream side EGR gas relay flow path 31 are vertically arranged in the EGR cooler connection base 33 , and a downstream side EGR gas relay flow path 32 and an upstream side EGR gas relay flow path 32 are arranged in the EGR cooler connection base 34 . A side cooling water flow path 39 is arranged vertically. The cooling water inlet of the downstream cooling water passage 38 and the EGR gas inlet of the downstream EGR gas relay passage 32 are arranged at the same height, while the cooling water outlet of the upstream cooling water passage 39 and the downstream EGR gas inlet are arranged at the same height. The EGR gas outlet of the gas relay passage 32 is arranged at the same height.

EGR gas relay passages 31, 32 and cooling water passages 38, 39 are provided in the EGR cooler connecting pedestals 33, 34 which are separately protruded, so that the heat in both the EGR cooler connecting pedestals 33, 34 is reduced. The effects of deformation are mitigated. Further, in the EGR cooler connecting pedestals 33, 34, the EGR gas flowing through the EGR gas relay passages 31, 32 is cooled by the cooling water flowing through the cooling water passages 38, 39, and the thermal deformation itself of the EGR cooler connecting pedestals 33, 34 is also suppressed. Furthermore, in each of the EGR cooler connection pedestals 33, 34, the EGR gas relay passages 31, 32 and the cooling water passages 38, 39 are arranged so as to replace their vertical height positions. Therefore, the heat distribution in the EGR cooler connecting pedestals 33 and 34 is vertically reversed, and the influence of thermal deformation in the height direction of the cylinder head 2 can be reduced.

The cylinder head 2 is provided with a spacer 46 that is connected to the periphery of the lower surface of the head cover 18 by means of an outer peripheral wall erected upward from the periphery of the upper surface. The spacer 46 has a plurality of openings 47 on its right side, through which fuel pipes 48 connecting injectors (not shown) provided in the cylinder head 2 and the common rail 16 are passed. ing. Since the spacer 46 is integrally provided above the cylinder head 2, the rigidity of the cylinder head 2 is increased, and not only the distortion of the cylinder head 2 itself can be reduced, but also the parts connected to the cylinder head 2 are reduced. can be supported with high rigidity.

Next, the configuration of the EGR device 24 will be described below with reference to FIGS. 9-11, 14, 15 and 17-19. As shown in FIGS. 9 to 11, 14, 15 and 17 to 19, the EGR device 24 includes a collector (body case) 25 which mixes fresh air and EGR gas and supplies them to the intake manifold 3. An intake manifold 3 and an intake throttle member 26 for introducing fresh air are connected through a collector 25 for communication. An EGR valve member 29 connected to the outlet side of the recirculated exhaust gas pipe 28 is communicatively connected to the collector 25 .

In the collector 25, the fresh air flow direction and the EGR gas flow direction intersect at right angles or form an obtuse angle. It is a direction that intersects with each of the flow directions. Further, a fresh air inlet 81 to which fresh air is supplied and an EGR gas inlet 82 to which EGR gas is supplied are distributed and opened on both front and rear sides of the collector 25, and an intake outlet 83 connected to the intake manifold 3 The left side of the collector 25 is opened. The EGR gas inlet 82 and the intake outlet 83 are arranged at the same height position, and the fresh air inlet 81 and the EGR gas inlet 82 are arranged at different height positions.

In the collector 25, the fresh air introduced from the intake throttle member 26 to the fresh air inlet 81 flows in an L-shaped bend in the vertical direction from the front-rear direction, while being introduced from the EGR valve member 29 to the EGR gas inlet 82. The EGR gas flows obliquely upward. Therefore, the EGR gas flows in the direction in which the fresh air flows, and the EGR gas is easily mixed with the fresh air. Further, the mixed gas of fresh air and EGR gas flows from the vertical direction to the horizontal direction while bending in an L-shape, and flows into the intake manifold 3 from the intake outlet 83 . Since the exit direction of the mixed gas intersects not only the direction of introduction of fresh air and the direction of introduction of EGR gas, but also the direction of flow of fresh air and EGR gas in the collector 25, the mixing distribution of EGR gas into the fresh air is can be homogenized.

As described above, in the collector 25, the EGR gas flow direction is 90° or more with respect to the fresh air flow direction. As such, the drift of the EGR gas in the intake manifold 3 can be suppressed. As a result, the EGR gas concentration of the intake air supplied to each of the plurality of intake passages 36 in the cylinder head 2 is made uniform, and variations in the combustion action of each cylinder in the diesel engine 1 can be suppressed. As a result, the generation of black smoke is suppressed, and the amount of NOx can be reduced while maintaining a good combustion state of the diesel engine 1 . That is, it is possible to clean the exhaust gas by recirculating the EGR gas without causing misfire in a specific cylinder.

The collector 25 is configured by connecting an upper case (first case) 84 having a fresh air inlet 81 and a lower case (second case) 85 having an EGR gas inlet 82 and an intake air outlet 83 . By configuring the collector 25 so that it can be vertically divided into an upper case 84 and a lower case 85, a mixing passage in which the EGR gas flow and the fresh air flow intersect at an angle of 90° or more can be easily formed in the collector 25. can. Therefore, not only can the collector 25 be made of a highly rigid casting, but also weight reduction can be achieved by using an aluminum-based casting.

The upper case 84 is provided with a downstream EGR gas flow path (first EGR gas flow path) 86a that is part of the EGR gas flow path 86 through which EGR gas flows, and a mixing chamber 87 that mixes fresh air and EGR gas. ing. An upstream EGR gas flow path (second EGR gas flow path) 86b that communicates the downstream EGR gas flow path 86a with the EGR gas inlet 82, and a mixed gas of fresh air and EGR gas is supplied from the mixing chamber 87 to the intake manifold. 3 is provided in the lower case 85 .

The lower case 85 is provided with the EGR gas inlet 82 , while the upper case 84 is provided with the fresh air inlet 81 and the mixing chamber 87 . The EGR gas flowing from the air flow crosses each other, and the fresh air and the EGR gas are efficiently mixed. Furthermore, since the lower case 85 is provided with the intake outlet 83, the fresh air that has flowed into the upper case 84 tries to flow toward the lower case 85. Mixing into air is homogenized. In addition, the EGR gas flow path 86, the mixing chamber 87, and the mixed gas flow path 88 can be configured compactly within the collector 25, and the size of the collector 25 can be reduced.

In plan view, the downstream EGR gas flow path 86a is connected to the side surface (left side surface) opposite to the side surface (left side surface) where the intake outlet 83 is provided with respect to the central axis of the mixing chamber 87, and is connected to the side surface (right side) opposite to the central axis. The side EGR gas flow path 86a and the upstream EGR gas flow path 86b are communicated with each other to form the EGR gas flow path 86 spirally. That is, the EGR gas flow path 86 formed by the downstream EGR gas flow path 86a and the upstream EGR gas flow path 86b has a curved shape that bulges to the opposite side (right side) of the intake outlet 83 in plan view. The bottom of the upstream EGR gas flow path 86b is composed of an inclined surface (an inclined surface sloping rearward and upward) from the EGR gas inlet 82 toward the upper case 84 .

Since the mixing chamber 87 communicates with the EGR gas flow path 86 on the opposite side of the intake outlet 83, the EGR gas flowing into the mixing chamber 87 is guided by the flow of fresh air and reaches the intake outlet 83. As a result, the EGR gas can be uniformly mixed with the fresh air. In addition, since the EGR gas flowing from the EGR gas flow path 86 into the mixing chamber 87 flows in the direction opposite to the flow from the mixing chamber 87 toward the mixed gas flow path 88, the fresh air and the EGR gas are mixed in the mixing chamber 87. The EGR gas is smoothly mixed with the fresh air as it flows in a collision manner.

Furthermore, since the EGR gas flows along the spiral EGR gas flow path 86 , the EGR gas flows into the mixing chamber 87 as a swirling flow forming a clockwise vortex. Since the turbulent EGR gas flows in the direction against the flow of the fresh air gas, the EGR gas is smoothly mixed with the fresh air flowing inside the mixing chamber 87 at the same time as it flows into the mixing chamber 87 . Therefore, in the collector 25, the fresh air and the EGR gas can be efficiently mixed while being stirred before being sent to the intake manifold 3 (the EGR gas can be smoothly dispersed in the mixed gas), and the gas mixture state in the collector 25 variation (unevenness) can be suppressed more reliably. As a result, a mixed gas with little unevenness is distributed to each cylinder of the diesel engine 1, and variations in the amount of EGR gas between the cylinders can be suppressed. The amount of NOx can be reduced while maintaining good conditions. Further, by making the EGR gas flow path 86 spiral, the EGR gas flowing into the mixing chamber 87 is sufficiently swirled, so that the length of the collector 25 in the front-rear direction can be shortened.

The lower surface flange 84a of the upper case 84 and the upper surface flange 85a of the lower case 85 are bolted, and the openings (fresh air inlet 81, EGR gas inlet 82, and intake air outlet 83) in three directions (front-back direction and left direction) are connected. ) is constructed. A fresh air outlet of the intake throttle member 26 is bolted to a rear flange 84b of the upper case 84 having the fresh air inlet 81 open. The intake throttle member 26 adjusts the amount of fresh air supplied to the collector 25 by adjusting the opening degree of an intake valve (butterfly valve) 26a provided therein.

The lower case 85 has an EGR gas outlet of the EGR valve member 29 bolted via a rectangular tubular relay flange 89 to a front flange 85 b having an EGR gas inlet 82 . The EGR valve member 29 adjusts the amount of EGR gas supplied to the collector 25 by adjusting the opening of an EGR valve (not shown) provided therein. A reed valve 90 inserted into the EGR gas inlet 82 is fixed inside the front flange 85 b of the lower case 85 . A relay flange (spacer) 89 bolted to the front flange 85 b covers the front of the reed valve 90 , so that the collector 25 has the reed valve 90 installed on the EGR gas inlet 82 side of the EGR gas flow path 86 . do.

The relay flange 89 has an EGR gas outlet 89 a that communicates with the EGR gas inlet 82 at the rear surface that connects with the collector 25 . Valve connecting seats 89b and 89c connected to the EGR valve member 29 project from the front surface of the relay flange 89, and the openings of the valve connecting seats 89b and 89c communicate with the EGR gas outlet of the EGR valve member 29. . In the relay flange 89 , the EGR gas joins the EGR gas inlets of the upper and lower valve connecting seats 89 b and 89 c and flows from the EGR gas inlet 82 through the reed valve 90 into the EGR gas flow path 86 in the collector 25 .

The EGR valve member 29 has an EGR valve (not shown) provided in an EGR gas flow path 29f provided in the valve main body 29e, and an actuator 29d for adjusting the opening degree of the EGR valve provided above the valve main body 29e. in the longitudinal direction and connected to the front of the collector 25 via a relay flange 89 . The EGR valve member 29 has upper and lower outlet side flanges 29a, 29b connected to the valve connecting seats 89b, 89c of the relay flange 89, respectively, on the rear surface of the lower valve body 29e. On the other hand, the front face of the EGR valve member 29 is provided with an inlet-side flange 29c having an EGR gas inlet that communicates with the EGR gas outlet of the recirculation exhaust gas pipe 28 .

The EGR valve member 29 allows the EGR gas cooled by the EGR cooler 27 to pass through the downstream EGR gas relay flow path 32 of the EGR cooler connection base 34 and the recirculation exhaust gas pipe 28, to the EGR gas inlet of the inlet side flange 29c. , the EGR gas is distributed vertically through the EGR gas flow path 29f of the valve body 29e. The EGR gas flowing vertically through the EGR gas flow path 29f is adjusted in flow rate by the EGR valve and flows into the relay flange 89 from the EGR gas outlets of the upper and lower outlet side flanges 29a and 29b.

The recirculation exhaust gas pipe 28 has a gas pipe portion 28a bent in an L shape in a plan view, and a plate-like rib 28b projecting from the inner peripheral side of the outer wall of the gas pipe portion 28a. The recirculation exhaust gas pipe 28 has an outlet flange 28c at one end (rear end) of the gas pipe portion 28a, which is connected to the inlet flange 29c of the EGR valve member 29, and is connected to the right side of the EGR cooler connection base 34. An inlet side flange 28d is provided at the other end (left end) of the gas pipe portion 28a. Further, the recirculation exhaust gas pipe 28 is provided with a sensor mounting seat 28e for mounting an EGR gas temperature sensor on the upper surface of the bent portion of the gas pipe portion 28a.

Since the EGR device 24 can be configured with a short collector 25, the distance between the EGR valve member 29 and the intake throttle member 26 can be shortened. Further, since the EGR valve member 29 has a structure in which the actuator 29d is provided above, the uppermost portions of the EGR valve member 29, the collector 25, and the intake throttle member 26 can be set to the same height. Not only can the height of the EGR device 24 be reduced, but also the lateral width of the EGR device 24 can be reduced. Therefore, since the EGR device 24 is compact, it can be easily connected to the right side of the cylinder head 2 integrally formed with the intake manifold 3 by adjusting the recirculation exhaust gas pipe 28. Contributes to miniaturization.

Since the recirculation exhaust gas pipe 28 has a configuration in which the flat ribs 28b are connected so as to connect both ends of the gas pipe portion 28a, the recirculation exhaust gas pipe 28 is configured with high rigidity and the cylinder head 2, the support strength on the front end side of the EGR device 24 is also increased. Further, since the recirculation exhaust gas pipe 28 has a structure in which the flat ribs 28b are provided along the EGR gas flow path 28f in the gas pipe portion 28a, the ribs 28b increase the heat radiation area in the gas pipe portion 28a. Therefore, the cooling effect of the EGR gas flowing through the EGR gas passage 28f is enhanced. As a result, the mixed gas refined by the EGR device 24 is cooled, and the effect of reducing the amount of NOx by the mixed gas can be easily maintained in an appropriate state.

Next, the configuration of the EGR cooler 27 will be described below with reference to FIGS. 9-11, 13-16, and 20-21. As shown in FIGS. 9 to 11, 13 to 16, and 20 to 21, the EGR cooler 27 includes a heat exchange portion 91 in which cooling water passages and EGR gas passages are alternately laminated, and a heat exchange section 91. A pair of left and right flange portions 92 and 93 are provided at both left and right end portions of one side surface of the portion 91 . A cooling water outlet 94 and a cooling water inlet 95 are distributed to the left and right flange portions 92 and 93, while an EGR gas inlet 96 and an EGR gas outlet 97 are distributed to the left and right flange portions 92 and 93. . Left and right flange portions 92 and 93 are connected to the front side surface of the cylinder head 2 , and the EGR cooler 27 is fixed to the cylinder head 2 .

By providing a cooling water opening and an EGR gas opening in each of the pair of left and right flanges 92 and 93, not only can the flanges 92 and 93 be formed of a common member, The material cost for the parts 92 and 93 can be suppressed. In addition, since the flange portions 92 and 93 are configured by drilling through holes 94 to 97 for cooling water and EGR gas respectively in a flat plate for connection with the cylinder head 2, the EGR cooler 27 can be easily manufactured. is. In addition, since the connecting portion between the flange portions 92 and 93 and the heat exchange portion 91 can be configured to a minimum, the amount of heat transferred from the cylinder head 2 to the heat exchange portion 91 can be reduced, and the EGR gas in the heat exchange portion 91 can be reduced. Increase cooling effect.

The EGR cooler 27 has flanges 92 and 93 projecting from the rear surface of the heat exchanging portion 91 , thereby forming a space between the heat exchanging portion 91 and the cylinder head 2 . Therefore, the EGR cooler 27 is in a state in which a wide range of the front and rear surfaces of the heat exchange portion 91 is exposed to the outside air, and heat is also radiated from the heat exchange portion 91, so the EGR gas cooling effect in the EGR cooler 27 is enhanced. Therefore, compared to the case where the rear surface of the heat exchange part 91 is attached to the front surface, the number of layers in the heat exchange part 91 can be reduced, and the front-rear length of the EGR cooler 27 can be shortened, so that the size of the diesel engine 1 can be reduced. .

The left flange portion 92 is provided with a cooling water outlet 94 and an EGR gas inlet 96 , while the right flange portion 93 is provided with a cooling water inlet 95 and an EGR gas outlet 97 . A cooling water outlet 94 and an EGR gas inlet 96 are vertically provided in the left flange portion 92, while an EGR gas outlet 97 and a cooling water inlet 95 are vertically provided in the right flange portion 93. . Also, the cooling water outlet 94 and the EGR gas outlet 97 are arranged at the same height, while the cooling water inlet 95 and the EGR gas inlet 96 are arranged at the same height.

At this time, the left and right flange portions 92, 93 of the EGR cooler 27 are connected to the EGR cooler connection pedestals 33, 34 formed so as to protrude from the front side surface of the cylinder head 2, respectively. The upstream EGR gas relay passage 31 and the downstream cooling water relay passage 38 in the left EGR cooler connection base 33 communicate with the EGR gas inlet 96 and the cooling water outlet 94 of the left flange portion 92, respectively. The downstream EGR gas relay passage 32 and the upstream cooling water relay passage 39 in the connecting base 34 communicate with the EGR gas outlet 97 and the cooling water inlet 95 of the right flange portion 93, respectively.

EGR gas relay passages 31, 32 and cooling water passages 38, 39 are formed in connecting pedestals 33, 34 to which flanges 92, 93 of the EGR cooler 27 are connected, and EGR gas inlets 96 and outlets are provided in the flanges 92, 93. 97 communicates with a cooling water outlet 94 and an inlet 95 . Therefore, it is not necessary to provide cooling water piping and EGR gas piping between the EGR cooler 27 and the cylinder head 2 . Therefore, the EGR cooler 27 is not affected by the expansion and contraction of the pipe due to EGR gas and cooling water, and the sealing performance at the connecting portion between the EGR cooler 27 and the cylinder head 2 can be ensured. , and can be compactly installed on the cylinder head 2.

Since the flange portion 92 is provided with the cooling water outlet 94 and the EGR gas inlet 96 at the top and bottom, and the flange portion 93 is provided with the EGR gas outlet 97 and the cooling water inlet 95 at the top and bottom, the flange portions 92 and 93 have the same shape. are attached to the heat exchanging portion 91 while being turned upside down. Therefore, it is possible to reduce the number of types of parts constituting the EGR cooler 27, improve the ease of assembly of the EGR cooler 27, and reduce the parts cost.

The flange portion 92 is provided with a cooling water outlet 94 and an EGR gas inlet 96 through which cooling water or EGR gas having a large amount of heat passes, while the flange portion 93 is provided with cooling water or EGR gas having a small amount of heat. A cooling water inlet 95 and an EGR gas outlet 97 are provided. Therefore, not only is distortion due to thermal deformation in each of the flange portions 92 and 93 suppressed, but also because the flange portions 92 and 93 are configured as separate bodies and are less affected by thermal deformation of each other, the EGR cooler 27 may be damaged or damaged. It can prevent failure.

In the rear view, the EGR cooler 27 has a cooling water outlet 94 and a cooling water inlet 95 arranged diagonally, and an EGR gas inlet 96 and an EGR gas outlet 97 arranged diagonally. Since EGR gas and cooling water with different heat amounts are respectively supplied or discharged from diagonal positions, thermal deformation at the connecting portion between the EGR cooler 27 and the cylinder head 2 is mitigated, suppressing bending and loosening of the connecting portion. can. Therefore, it is possible not only to prevent leakage of EGR gas and cooling water between the EGR cooler 27 and the cylinder head 2, but also to prevent deterioration of the connection strength.

A plate-shaped gasket 98 is sandwiched between the cylinder head 2 and the flanges 92 and 93 so as to bridge the left and right flanges 92 and 93 . An O-ring 99, which is a ring-shaped seal member, is embedded in each of the cooling water inlet and the cooling water outlet of the cylinder head 2 that communicate with the cooling water outlet 94 and the cooling water inlet 95 of the flange portions 92 and 93, respectively. It is covered with flange portions 92 and 93 .

Since the separate flange portions 92 and 93 are connected to the connection bases 33 and 34 of the cylinder head 2 via the gasket 98, tension acts on the gasket 98 due to thermal deformation at the connection portion with the cylinder head 2. . Therefore, the gasket 98 improves the sealing performance (sealing performance) at the connecting portions of the EGR gas inlet 96 and the EGR gas outlet 97 , preventing leakage of EGR gas traveling between the cylinder head 2 and the EGR cooler 27 . can be prevented. In addition, since the O-ring 99 is embedded in the space defined by the cooling water inlet and cooling water outlet of the connecting pedestals 33 and 34 of the cylinder head 2 and the rear end surfaces of the flanges 92 and 93, the cooling water flows. At this time, the communicating portions of the connecting pedestals 33, 34 and the flange portions 92, 93 come into contact with the O-ring 99, so that the sealing performance of the connecting portions at the cooling water inlets and outlets 94, 95 can be ensured. Therefore, even if the EGR cooler 27 for inflow and outflow of liquid and gas is connected to the cylinder head 2, it is possible to ensure sealing performance for each of the liquid and gas, and to prevent leakage of each of EGR gas and cooling water.

A through hole 100 for bolting is drilled at an outer peripheral portion of the flange portions 92 and 93 at an outer position. That is, the left flange portion 92 has five through holes 100 on the top, bottom, and left side, and the right flange portion 93 has five through holes 100 on the top, bottom, and right side. Therefore, the left flange portion 92 is provided with through holes 100 on the upper side of the cooling water outlet 94, the lower side of the EGR gas inlet 96, and the left side between the cooling water outlet 94 and the EGR gas inlet 96, respectively. 2, the sealing performance at the cooling water outlet 94 and the EGR gas inlet 96 is ensured. Similarly, the right flange portion 93 is provided with through holes 100 below the cooling water inlet 95, above the EGR gas outlet 97, and on the right side between the cooling water inlet 95 and the EGR gas outlet 97, respectively. When bolted to the connecting seat 34 of the head 2 , sealing performance is ensured at the cooling water inlet 95 and the EGR gas outlet 97 .

The gasket 98 is configured by pasting together two plates 98a and 98b provided with through holes 101 to 103. EGR gas passes through the through hole (EGR gas through hole) 101, and the through hole (cooling water Cooling water passes through the through hole 102 for bolts, and a fastening bolt is inserted into the through hole (through hole for bolt) 103 . The gasket 98 has a shape in which the inner peripheral edge of the EGR gas through hole 101 is branched so as to warp in the front-rear direction, and the opening area of the cooling water through hole 102 is larger than the opening areas of the cooling water inlets and outlets 94 and 95 . is configured to be wider.

The gasket 98 warps forward the inner peripheral edge of the EGR gas through hole 101 of the front side plate 98a, and warps the inner peripheral edge of the EGR gas through hole 101 of the rear side plate 98b rearward. By welding the 98a and the rear side plate 98b together, the inner peripheral edge of the EGR gas through hole 101 has a Y-shaped cross section. By forming the inner peripheral edge of the EGR gas through hole 101 into a shape that is warped back and forth, the front and rear surfaces of the inner peripheral edge of the EGR gas through hole 101 are brought into close contact with the respective end surfaces of the connecting pedestals 33 and 34 and the flange portions 92 and 93. As a result, sufficient airtightness can be secured.

The gasket 98 is configured so that the opening of the cooling water through hole 102 is wider than the cooling water inlets and outlets 94 and 95 , so that the O-ring 99 is inserted into the cooling water through hole 102 . That is, the communicating portions between the cooling water inlets and outlets 94, 95 of the flange portions 92, 93 and the cooling water relay passages 38, 39 in the connecting pedestals 33, 34 are fitted into the cooling water through holes 102 of the gasket 98. O-ring 99 seals.

In addition, the connecting pedestals 33 and 34 of the cylinder head 2 open the cooling water inlet/outlet ports 94 and 95 with steps, respectively, so that the passage diameters of the cooling water relay passages 38 and 39 in the connecting pedestals 33 and 34 are larger. An O-ring 99 is fitted on the outer peripheral side of the cooling water relay passages 38 , 39 with respect to the cooling water inlets and outlets 94 , 95 of the connecting pedestals 33 , 34 . That is, the O-ring 99 is inserted into the gasket 98 and fitted to the stepped portions of the cooling water inlets and outlets 94 and 95 of the connection bases 33 and 34, and is held between the connection bases 33 and 34 and the flange portions 92 and 93. be done. Therefore, when the cooling water passes through the inside of the O-ring 99 made of an elastic material, the O-ring 99 is deformed so as to spread outward, and is brought into close contact with the connecting pedestals 33, 34 and the flanges 92, 93. , to ensure the sealing performance of the cooling water.

The ring-shaped O-ring 99 has an inner peripheral portion that bulges forward and backward, and is pressed by cooling water passing through the inner peripheral portion of the O-ring 99, so that the front and rear edges of the inner peripheral portion swell forward and backward. Deform to protrude. As a result, the inner peripheral portion of the O-ring 99 is brought into close contact with the connection pedestals 33, 34 and the flange portions 92, 93, so that the cooling water sealing performance at the connection portion between the cylinder head 2 and the EGR cooler 27 can be improved.

Further, the ring-shaped O-ring 99 has a shape in which the inner peripheral portion bulges forward and backward, and the inner peripheral surface thereof has a recessed portion. That is, by configuring the inner peripheral surface of the O-ring 99 with a Y-shaped cross section that is warped back and forth, the cooling water passing through the inner peripheral portion of the O-ring 99 presses the front and rear edges of the inner peripheral portion. is further protruded forward and backward, and the adhesion between the inner peripheral portion of the O-ring 99 and the connection bases 33, 34 and the flange portions 92, 93 is improved. It is possible to improve the water sealability.

Next, the configuration of the two-stage supercharger 30 will be described below with reference to FIGS. 22 to 27 and the like. As shown in FIGS. 22 to 27, the two-stage supercharger 30 compresses fresh air flowing into the intake manifold 3 of the cylinder head 2 using the fluid energy of exhaust gas discharged from the exhaust manifold 4 . The two-stage supercharger 30 is composed of a high-pressure supercharger 51 connected to the exhaust manifold 4 and a low-pressure supercharger 52 connected to the high-pressure supercharger 51 .

A high-pressure supercharger 51 is arranged on the left side of the exhaust manifold 4 and a low-pressure supercharger 52 is arranged above the exhaust manifold 4 . That is, while the small-capacity high-pressure supercharger 51 is arranged to face the exhaust manifold 4, the large-capacity low-pressure supercharger 52 is installed above the exhaust manifold 4 so as to protrude leftward from the cylinder head 2. placed in Therefore, not only can the exhaust manifold 4 and the two-stage supercharger 30 be arranged compactly in the space on the left side of the cylinder head 2, but also the top position of the two-stage supercharger 30 can be positioned lower than the top position of the diesel engine 1. position and can. Therefore, not only can it contribute to downsizing of the diesel engine 1, but also the low-pressure supercharger 52 can be arranged near the cylinder head 2 and the two-stage supercharger 30 can be fixed with high rigidity.

The high pressure supercharger 51 comprises a high pressure turbine 53 communicating with the exhaust outlet 44 of the exhaust manifold 4 and a high pressure compressor 54 supplying compressed air to the intake manifold 3 . The high-pressure compressor 54 supplies compressed air to the intake manifold 3 via the EGR device 24 by communicating with the fresh air inlet 81 (see FIG. 17 etc.) of the intake throttle member 26 via an intercooler (not shown). do. On the other hand, the low-pressure supercharger 52 includes a low-pressure turbine 55 whose exhaust inlet communicates with the exhaust outlet of the high-pressure turbine 53 via an exhaust-side relay pipe, and a fresh-air inlet of the high-pressure compressor 54 via a fresh-air-side relay pipe. The low-pressure compressor 56 is arranged above the high-pressure turbine 53, and the high-pressure compressor 54 is arranged on one side before and after the high-pressure turbine 53. A low-pressure turbine 55 is arranged on the front and rear sides of the compressor 56 .

The exhaust manifold 4 has an exhaust outlet 44 for discharging exhaust gas that opens toward one of the left and right sides. The high-pressure turbine 53 has an exhaust inlet 57 that opens toward the exhaust manifold 4 and an exhaust outlet 58 that opens forward. The low-pressure turbine 55 has an exhaust inlet 60 that opens downward and an exhaust outlet 61 that opens forward.

The exhaust outlet 44 of the exhaust manifold 4 and the exhaust inlet 57 of the high-pressure turbine 53 facing each other are connected by bolts with a flange, and the high-pressure supercharger 51 is fixed on the left side of the exhaust manifold 4 . An exhaust outlet 58 of the high-pressure turbine 53 is bolted to one end (rear end) of an L-shaped high-pressure exhaust gas pipe 59 (exhaust-side relay pipe) with a flange, while an exhaust inlet 60 of the low-pressure turbine 55 is connected to the high-pressure exhaust pipe. The low-pressure supercharger 52 is fixed above the high-pressure supercharger 51 by bolting to the other end (upper end) of the gas pipe 59 with a flange.

A high-pressure turbine 53 is connected to the exhaust manifold 4 by flange connection to support the high-pressure supercharger 51 with high rigidity. The low-pressure supercharger 52 can be supported from below by the high-pressure supercharger 51 by connecting the 55 by flange connection. Further, since the low-pressure supercharger 52 is installed near the upper side of the exhaust manifold 4, the center of gravity of the low-pressure supercharger 52 is located above the connection position between the exhaust manifold 4 and the high-pressure supercharger 51. Become. Therefore, in the vicinity of the diesel engine 1, the two-stage supercharger 30 can be supported with high rigidity and in a compact manner.

The high-pressure compressor 54 has a fresh air intake port 63 (fresh air inlet) opened rearward, and a fresh air supply port 64 (fresh air outlet) opened downward. On the other hand, the low-pressure compressor 56 has a fresh air intake port 66 (fresh air inlet) that opens rearward, and a fresh air supply port 67 (fresh air outlet) that protrudes from the left side and is directed rearward. ing. One end of a U-shaped low-pressure fresh air passage pipe 65 (fresh-air side relay pipe) is fixed to the fresh-air intake port 63 (fresh-air inlet) of the high-pressure compressor 54. The end and the fresh air supply port 67 (fresh air outlet) of the low pressure compressor 56 are connected.

The high-pressure compressor 54 and the low-pressure compressor 56 are connected by a rear U-shaped low-pressure fresh air passage pipe 65, and the front portion of the low-pressure supercharger 52 is connected to the high-pressure supercharger 51 supported by the exhaust manifold 4 with high rigidity. can be fixed. The low-pressure compressor 56 has a fresh air intake port 66 and a fresh air supply port 67 extending in the same direction (rear), and an air supply pipe 62 and a low-pressure fresh air passage pipe 65 communicating with an air cleaner (not shown). Since it has a configuration that facilitates connection, it is possible to improve assembly workability.

The low-pressure fresh air passage pipe 65 includes a metal pipe 65a whose one end is bolted to the fresh air intake port 66 of the high-pressure compressor 54 by flange connection, and the other end of the metal pipe 65a and the fresh air supply port 67 of the low-pressure compressor 56. It is configured by a resin pipe 65b that communicates with the resin pipe 65b. As a result, the metal pipe 65a of the low-pressure fresh air passage pipe 65 is fixed to the high-pressure compressor 54 with high rigidity, while the resin pipe 65b allows the low-pressure compressor 56 and the metal pipe 65a to communicate with each other while reducing assembly errors. can.

Since the fresh air supply port 67 of the low-pressure compressor 56 protrudes leftward from the left side surface of the low-pressure compressor 56 and is configured toward the rear upper side, the bent portion of the low-pressure fresh air passage pipe 65 (metal pipe 65a) increases the curvature of Therefore, the occurrence of turbulence in the low-pressure fresh air passage pipe 65 is suppressed, and the compressed air discharged from the low-pressure compressor 56 is smoothly supplied to the high-pressure compressor 54 .

A blow-by gas reducing device 19 for taking in blow-by gas is installed on the cylinder head 2 . The blow-by gas return device 19 is placed and fixed on the upper surface of a head cover 18 that covers the upper surface of the cylinder head 2 . A blow-by gas outlet 70 provided behind the blow-by gas reducing device 19 is connected to an air supply pipe 62 connected to a fresh air intake port 66 (fresh air inlet) of the low-pressure compressor 56 via a return hose 68 . An air supply pipe 62 is arranged between the low-pressure fresh air passage pipe 65 (fresh air side relay pipe) and the cylinder head 2 .

Since the air supply pipe 62 is connected to the rear of the low-pressure supercharger 52, which is a component on the upper side of the two-stage supercharger 30, and is arranged near the cylinder head 2, the blow-by gas reduction device is arranged above the cylinder head 2. 19 and the air supply pipe 62 can be made closer. Therefore, the reduction hose 68 can be shortened, and the inside of the reduction hose 68 can be prevented from freezing in a low-temperature environment. The air supply pipe 62 is arranged in a space surrounded by the low-pressure fresh air passage pipe 65 and the cylinder head 2, so that it is possible to prevent damage due to an external force at the connecting portion between the air cleaner (not shown) and the resin pipe. .

The high-pressure supercharger 51 has a fresh air supply port 64 that is open downward and protrudes from the lower surface of the high-pressure compressor 54 on the side of the cylinder head 2 . The high-pressure compressor 54 is connected to a high-pressure fresh air passage pipe 71 communicating with an intercooler (not shown), and supplies compressed air to the intercooler via the high-pressure fresh air passage pipe 71 . Below the high-pressure compressor 54, a cooling water inlet pipe 22 is provided that opens leftward. By connecting the high-pressure fresh air passage pipe 71 to the rear left side surface of the cylinder block 6 together with the cooling water pipe communicating with the radiator (not shown), the cooling water inlet pipe 22 and the fresh air supply port 64 of the high-pressure compressor 54 can be connected respectively. . Therefore, since it is possible to consolidate the routing of the cooling water pipes and the high-pressure fresh air passage pipes 71, not only is it possible to simplify the pipe structure on the side of the machine in which the diesel engine 1 is mounted, but also the assembly work and maintenance work can be facilitated. state can be configured.

In the diesel engine 1, the cooling water outlet pipe 23, the air supply pipe 62, and the intake throttle member 26 are arranged above the cylinder head 2 and on the cooling fan 9 side. Therefore, on the machine side where the diesel engine 1 is mounted, a radiator (not shown) that uses the cooling air of the cooling fan 9, an air cleaner (not shown), and an intercooler (not shown) are arranged behind the cooling fan 9. In this case, not only can the cooling water pipes connected to the radiator and the fresh air pipes communicating with the air cleaner and intercooler be shortened, but also the pipe connection work can be performed collectively. Therefore, not only is the assembling workability and maintenance workability on the machine side easy, but also the parts to be connected to the diesel engine 1 can be arranged efficiently on the machine side.

An exhaust outlet 58 of the high-pressure turbine 53 is provided with a turbine exhaust hole 58a through which exhaust gas for rotating a turbine wheel (not shown) is discharged, a bypass hole 58b through which the exhaust inlet 57 and the exhaust outlet 58 are communicated, and a bypass hole 58b. A waste gate valve 69 that opens and closes is provided. By arranging the turbine exhaust hole 58 a and the bypass hole 58 b side by side at the exhaust outlet 58 of the high pressure turbine 53 , whether or not the high pressure supercharger 51 performs the compression operation can be set according to the rotational speed of the diesel engine 1 . Therefore, exhaust energy can be efficiently used in the two-stage supercharger 30 to stabilize the amount of fresh air supplied to the combustion chamber, thereby increasing the engine output and reducing the amount of black smoke emitted.

Further, since the bypass path from the exhaust manifold 4 to the low-pressure turbine 55 is configured by opening the bypass hole 58b of the high-pressure turbine 53, only the high-pressure exhaust gas pipe 59 for communicating the high-pressure turbine 53 and the low-pressure turbine 55 is provided. A bypass pipe for communication between the exhaust manifold 4 and the low-pressure turbine 55 is not required. Therefore, not only the piping structure in the two-stage turbocharger 30 is simplified, but also the space around the two-stage turbocharger 30 can be expanded. A hydraulic pump (not shown) can be arranged in parallel with the starter 20 for starting the engine.

The high-pressure supercharger 51 has a high-pressure hydraulic oil supply pipe 73 and a high-pressure hydraulic oil return pipe 74 connected to the upper and lower sides of a center housing 72 which is a connecting portion of the high-pressure turbine 53 and the high-pressure compressor 54 . Similarly, in the low-pressure supercharger 52 , a low-pressure hydraulic oil supply pipe 76 and a low-pressure hydraulic oil return pipe 77 are connected above and below a center housing 75 that is a connecting portion of the low-pressure turbine 55 and the low-pressure compressor 56 .

The high-pressure hydraulic oil supply pipe 73 has a lower end connected to a connecting member 78 installed on the left side surface of the cylinder block 6 and an upper end connected to the upper surface of the center housing 72 of the high-pressure supercharger 51 . A connecting joint 79 is installed on the upper surface of the center housing 72 of the high-pressure supercharger 51 to allow the upper end of the high-pressure hydraulic oil supply pipe 73 and the lower end of the low-pressure hydraulic oil supply pipe 76 to communicate with each other. The upper end of the low-pressure hydraulic oil supply pipe 76 is connected to the upper surface of the center housing 75 of the low-pressure supercharger 52 . As a result, the hydraulic fluid flowing through the oil passages in the cylinder block 6 is supplied to the center housing 72 of the high-pressure supercharger 51 through the high-pressure hydraulic fluid supply pipe 73, and the high-pressure hydraulic fluid supply pipe 73 and the low-pressure hydraulic fluid supply pipe 73 The oil is supplied to the center housing 75 of the low-pressure supercharger 52 through the oil supply pipe 76 .

The high-pressure hydraulic oil supply pipe 73 passes between the cylinder head 2 and the cylinder block 6 and the high-pressure supercharger 51 , and is routed around the rear of the exhaust outlet 44 of the exhaust manifold 4 . Also, the low-pressure hydraulic oil supply pipe 76 is arranged in an L-shape along the upper surface of the high-pressure supercharger 51 and the center housing 75 of the low-pressure supercharger 52 . In this way, by shortening the hydraulic oil supply pipes 73 and 76 and circulating them so as to surround them with the two-stage supercharger 30, which is a highly rigid component, the hydraulic oil is efficiently supplied to the two-stage supercharger 30. At the same time, damage to the hydraulic oil supply pipes 73 and 76 due to external force can be prevented.

One end (lower end) of the high-pressure hydraulic oil return pipe 74 is connected to the tip (left tip) of a connecting joint 80 installed on the left side surface of the cylinder block 6 , and the other end (upper end) is connected to the high-pressure supercharger 51 . is connected to the lower surface of the center housing 72 of the. One end (lower end) of the low-pressure hydraulic oil return pipe 77 is connected to the branched upper end of the connection joint 80 , and the other end (upper end) is connected to the lower surface of the center housing 75 of the low-pressure supercharger 52 . . Therefore, hydraulic fluid flowing through the high-pressure supercharger 51 and the low-pressure supercharger 52 respectively flows from the low-pressure hydraulic fluid return pipes 74, 77 below the center housings 72, 75 and joins at the connecting joint 80 to produce oil in the cylinder block 6. put back on the road.

The high-pressure hydraulic oil return pipe 74 is routed around the rear of the exhaust outlet 44 of the exhaust manifold 4 . Further, the low-pressure operation return pipe 77 passes between the cylinder head 2 and the cylinder block 6 and the high-pressure supercharger 51 and is routed around the front of the exhaust outlet 44 of the exhaust manifold 4 . In this way, by shortening the hydraulic oil return pipes 74 and 77 and arranging them so as to surround them with the two-stage supercharger 30, which is a highly rigid component, the hydraulic oil is efficiently supplied to the two-stage supercharger 30. At the same time, damage to the hydraulic oil return pipes 74 and 77 due to external force can be prevented.

Next, configurations of the cooling water pump 21 and the cooling water inlet pipe 22 will be described below with reference to FIGS. 28 and 29 and the like. As shown in FIGS. 28 and 29, etc., a cooling water pump mounting portion 319 to which the cooling water pump 21 (see FIG. 2, etc.) is mounted, and a cooling water inlet pipe 22 are mounted on the left side surface of the cylinder block 6 near the rear side surface. (See FIG. 3, etc.) is provided with an inlet pipe mounting seat 320 projecting therefrom. The cooling water pump mounting portion 319 and the inlet pipe mounting seat 320 are formed integrally with the cylinder block 6 . A rear side portion of the inlet pipe mounting seat 320 is connected to the cooling water pump mounting portion 319 . The cooling water pump mounting portion 319 and the inlet pipe mounting seat 320 protrude in a direction away from the crankshaft 5 to improve the rigidity, strength and cooling efficiency of the cylinder block 6 .

A cooling water pump 21 for cooling water circulation is bolted to a rear side surface 312 of the cylinder block 6 and a cooling water pump mounting portion 319 . The cooling water pump 21 is roughly divided into a base plate portion 331 , a cover plate portion 332 and a pump pulley 333 .

The base plate portion 331 and the cover plate portion 332 are provided with five through bolt holes provided in the peripheral portion of the base plate portion 331 and through holes of the cover plate portion 332 corresponding to the through bolt holes, from the cover plate portion 332 side. The cover bolts 347 are inserted and tightened, respectively, and the peripheral portions are tightly fixed to each other.

In addition, the cooling water pump 21 is configured such that mounting bolts 348 are inserted into nine through-holes provided on the periphery of the base plate portion 331 and the cover plate portion 332 so that the plate portions 331 and 332 are tightened together. It is bolted to the cylinder block 6 . By tightening the mounting bolts 348, the peripheral portions of the base plate portion 331 and the cover plate portion 332 are tightly fixed to each other, and the peripheral portion of the cooling water passage outlet 327 of the cylinder block 6 and the pump suction port 334 of the cooling water pump 21 are brought into contact with each other. The peripheral portions are tightly fixed to each other, and further, the peripheral portion of the cooling water inlet 328 of the cylinder block 6 and the peripheral portion of the pump discharge port 335 of the cooling water pump 21 are tightly fixed to each other. One or two mounting bolts 348 are arranged between adjacent cover bolts 347 , 347 in the arrangement of bolts 347 , 348 along the periphery of the cooling water pump 21 .

Since the base plate portion 331 and the cover plate portion 332 are connected by the cover bolts 347 , the cooling water pump 21 can be distributed as one component, and when the cooling water pump 21 is mounted on the cylinder block 6 by the mounting bolts 348 , installation work becomes easier.

The base plate portion 331 includes, for example, a cooling water pump mounting portion 319 and a pump suction port 334 connected to a cooling water passage outlet 327 opened at a left-side portion of the rear side surface of the cylinder block 6 . A pump discharge port 335 connected to a cooling water introduction port 328 opened at a left-side portion of the rear side surface is provided.

The base plate portion 331 and the cover plate portion 332 are in close contact with each other at their peripheries to form a pump cooling water passage 336 connecting a pump suction port 334 and a pump discharge port 335 . An annular seal member surrounding a pump suction port 334 , a pump discharge port 335 , and a pump cooling water passage 336 is arranged at the contact portion between the base plate portion 331 and the cover plate portion 332 . The cover plate portion 332 rotatably supports a pump shaft 337 to which an impeller is fixed at one end. A pump pulley 333 is fixed to the other end of the pump shaft 337 .

A cooling water passage inlet 329 is opened on the left side surface of the cylinder block 6 . The cooling water passage inlet 329 opens into an inlet pipe mounting seat 320 projecting from the left side. Inside the cylinder block 6, a substantially L-shaped in-block cooling water passage 338 (cooling water passage) is formed that connects a cooling water passage inlet 329 opened on the left side surface and a cooling water passage outlet 327 opened on the rear side surface. It is

A pair of bolt holes are formed in the inlet pipe mounting seat 320 across the cooling water passage inlet 329 , and the cooling water inlet pipe 22 (cooling water inlet member) having the cooling water inlet 339 is attached to and detached from the inlet pipe mounting seat 320 . Can be bolted together. The cooling water inlet pipe 22 is connected to a pipe leading to the cooling water outlet of the radiator. The cooling water from the radiator is taken into the engine 1 from the cooling water inlet pipe 22 and introduced into the cylinder block 6 from the cooling water inlet 328 via the block cooling water passage 338 and the cooling water pump 21 .

In the engine 1 of this embodiment, the cooling water inlet pipe 22 having the cooling water inlet 339 is detachably attached to the cooling water passage inlet 329 leading to the pump suction port 334 of the cooling water pump 21 . The position of the cooling water inlet 339 can be changed only by changing the shape or the like. As a result, the position of the cooling water inlet 339 of the cooling water pump 21 can be easily changed without causing a large design change or an increase in manufacturing cost.

A cooling water passage outlet 327 for supplying cooling water from the radiator to the cooling water pump 21 and a cooling water inlet 328 for introducing cooling water from the cooling water pump 21 into the cylinder block 6 are provided on the left and right sides of the cylinder block 6. They are arranged separately. Further, a pump internal cooling water passage 336 connecting the cooling water passage outlet 327 and the cooling water inlet 328 is arranged from a portion near the left side of the cylinder block 6 to a portion near the right side thereof. With this configuration, the cooling water passing through the pump internal cooling water passage 336 is cooled by the cooling air from the cooling fan 9 (see FIG. 2) while moving from the cooling water passage outlet 327 to the cooling water inlet 328. be done. Therefore, the cooling water can be cooled in the cooling water pump 21 before it is introduced into the cylinder block 6 through the cooling water inlet 328, so the cooling efficiency of the engine 1 can be improved.

The configuration of each part in the present invention is not limited to the illustrated embodiment, and various modifications are possible without departing from the gist of the present invention.

<Additional remarks of the invention>
An engine device according to one aspect includes an exhaust manifold and an intake manifold arranged in a cylinder head, and a supercharger for compressing fresh air flowing into the intake manifold by fluid energy of exhaust gas discharged from the exhaust manifold. The engine device comprises a two-stage supercharger, wherein the supercharger is a high-pressure supercharger connected to the exhaust manifold and a low-pressure supercharger connected to the high-pressure supercharger, The low-pressure compressor of the low-pressure supercharger has a fresh air inlet closer to the cylinder head than a fresh air outlet.

In the above engine device, the fresh air outlet may be provided so as to protrude from one left and right side of the low-pressure compressor.

In the above engine device, the low-pressure compressor may have the fresh air inlet and the fresh air outlet directed to one side in the front-rear direction.

In the above engine apparatus, the fresh air inlet of the high pressure compressor of the high pressure supercharger may face one of the front and rear sides.

In the engine device described above, the high-pressure supercharger may be arranged on one left and right side of the exhaust manifold, and the low-pressure supercharger may be arranged above the exhaust manifold.

According to the above configuration, the fresh air inlet of the low-pressure supercharger is arranged in a space surrounded by the fresh air outlet of the low-pressure supercharger and the cylinder head. Therefore, it is possible to prevent damage, etc. caused by an external force at a connecting portion between an air cleaner (not shown) and a resin pipe.

1 Engine 2 Cylinder Head 3 Intake Manifold 4 Exhaust Manifold 5 Crankshaft 6 Cylinder Block 7 Flywheel Housing 8 Flywheel 9 Cooling Fan 51 High Pressure Supercharger 52 Low Pressure Supercharger 53 High Pressure Turbine 54 High Pressure Compressor 55 Low Pressure Turbine 56 Low Pressure Compressor 57 Exhaust inlet 58 Exhaust outlet 58a Turbine exhaust hole 58b Bypass hole 59 High pressure exhaust gas pipe 60 Exhaust inlet 61 Exhaust outlet 62 Air supply pipe 63 Fresh air intake 64 Fresh air supply port 65 Low pressure fresh air passage pipe 65a Metal pipe 65b Resin pipe 66 New Air intake port 67 Fresh air supply port 68 Reduction hose 69 Waste gate valve 70 Blow-by gas outlet 71 High pressure fresh air passage pipe 72 Center housing 73 High pressure hydraulic oil supply pipe 74 High pressure hydraulic oil return pipe 75 Center housing 76 Low pressure hydraulic oil Supply pipe 77 Low-pressure hydraulic oil return pipe 78 Connection member 79 Connection joint 80 Connection joint

Claims (5)

An engine device comprising: an exhaust manifold and an intake manifold arranged in a cylinder head;
The supercharger is composed of a two-stage supercharger comprising a high-pressure supercharger connected to the exhaust manifold and a low-pressure supercharger connected to the high-pressure supercharger,
The center of the low-pressure supercharger is arranged closer to the cylinder head than the center of the high-pressure supercharger in a plan view ,
The high-pressure supercharger is an engine device arranged at a position facing the exhaust manifold from a side opposite to the cylinder head . 2. The engine apparatus according to claim 1 , wherein the fresh air outlet of the low-pressure compressor of the low-pressure supercharger is provided so as to protrude from one left and right side of the low-pressure compressor. 3. The engine apparatus according to claim 2 , wherein said low-pressure compressor has a fresh air inlet and said fresh air outlet directed to one side in the front-rear direction. 4. The engine apparatus according to claim 3, wherein a fresh air inlet of a high-pressure compressor of said high-pressure supercharger faces one of said front and rear sides. The engine device according to any one of claims 1 to 4 , wherein the high-pressure supercharger is arranged on one left and right side of the exhaust manifold, and the low-pressure supercharger is arranged above the exhaust manifold. .

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