JP7035146B2 - Engine equipment - Google Patents

Description

The present invention relates to an engine device including a supercharger.

Conventionally, for the purpose of improving engine output and fuel efficiency, a supercharger that compresses fresh air with exhaust energy is mounted on the engine device in order to increase the air density in the cylinder of the engine (see Patent Document 1). .. In a diesel engine, a large amount of high-density air is supplied into 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. It is also possible to suppress mixed combustion and reduce NOx emissions.

In addition, a single-stage turbocharger with one turbocharger has a limit to the requirements of a high-power engine, so two turbochargers are connected in series with a high-pressure stage and a low-pressure stage. An engine equipped with a turbocharger has been proposed (see Patent Document 2).

Japanese Patent No. 4517550 Japanese Patent No. 5237785

By the way, the mounting space of the diesel engine varies depending on the work vehicle (construction machine, agricultural work machine, etc.) to be mounted, but in recent years, the mounting space is limited (narrow) due to the demand for weight reduction and compactness. many. Therefore, it is necessary to lay out the components of the diesel engine compactly. In addition to the problem of limited mounting space, the cylinder head is required to have a highly rigid structure in order to connect and support parts such as an EGR device and a turbocharger to the cylinder head.

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

It is a technical subject of the present invention to provide an engine device which has been improved by examining the above-mentioned current situation.

The present invention is an engine device including an exhaust manifold and an intake manifold arranged on a cylinder head, and a supercharger that compresses fresh air flowing into the intake manifold by the fluid energy of exhaust gas discharged from the exhaust manifold. The supercharger is composed of a high-pressure turbocharger connected to the exhaust manifold and a low-pressure turbocharger connected to the high-pressure turbocharger, and is composed of a two-stage turbocharger. In the low-pressure compressor of the machine, the fresh air inlet is provided on the cylinder head side of the fresh air outlet.

In the engine device, the fresh air outlet may be provided so as to project from the left and right sides of the low pressure compressor.

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

In the engine device, the fresh air inlet of the high-pressure compressor of the high-pressure turbocharger may be directed to one side in the front-rear direction.

In the engine device, the high-pressure turbocharger may be arranged on the left and right sides of the exhaust manifold, and the low-pressure turbocharger may be arranged above the exhaust manifold.

According to the present invention, since the fresh air inlet of the low-pressure turbocharger is arranged in the space surrounded by the fresh air outlet of the low-pressure turbocharger and the cylinder head, it can only contribute to the miniaturization of the engine device. It is possible to prevent damage due to external force at the connecting portion between the air cleaner and the resin pipe connected to the air cleaner (not shown).

It is a front view of an engine. It is a rear view of an engine. It is a left side view of the engine. It is a right side view of an engine. It is a plan view of an engine. It is a bottom view of an engine. It is a perspective view which looked at the engine diagonally from the front. It is a perspective view which looked at the engine diagonally from the rear. It is an enlarged perspective view which looked at the cylinder head from the intake manifold side. It is an exploded perspective view which looked at the cylinder head from the exhaust manifold side. It is an exploded perspective view which looked at the cylinder head 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 sectional drawing from the cylinder head and EGR apparatus. It is sectional drawing of the cylinder head and the exhaust manifold. It is sectional drawing of the connection part with EGR cooler in a cylinder head. It is sectional drawing from the EGR apparatus. It is a top view of the EGR apparatus. It is an exploded perspective view of the EGR apparatus. It is an exploded view of the connection part with an EGR cooler in a cylinder head. It is sectional drawing of the connection part with EGR cooler in a cylinder head. It is a left side view of an engine for demonstrating the arrangement of a two-stage turbocharger. It is a rear view enlarged view of an engine. It is a front enlarged view of an engine. It is a left side view of a two-stage turbocharger. It is a perspective view of a two-stage turbocharger. It is a right side view of a two-stage turbocharger. It is an exploded perspective view of a cooling water pump. It is a partial sectional view of the cooling water pump mounting part.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. First, the overall structure of the diesel engine (engine device) 1 will be described with reference to FIGS. 1 to 8. In the following description, both sides parallel to the crank shaft 5 (sides on both sides of the crank shaft 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. For the sake of convenience, these are used as the reference for the positional relationship between the four sides and the top and bottom of the diesel engine 1.

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

The front and rear tip sides of the crank shaft 5 are projected from both front and rear surfaces of the cylinder block 6. The flywheel housing 7 is fixed to one side of the diesel engine 1 that intersects with the crank shaft 5 (in the embodiment, the front side surface side of the cylinder block 6). The flywheel 8 is arranged in the flywheel housing 7. The flywheel 8 is pivotally supported on the front end side of the crank shaft 5 and is configured to rotate integrally with the crank shaft 5. The operating portion of a work machine (for example, a hydraulic excavator, a forklift, etc.) is configured to take out the power of the diesel engine 1 via the flywheel 8. A cooling fan 9 is provided on the other side of the diesel engine 1 that intersects with the crank shaft 5 (in the embodiment, the rear side surface side of the cylinder block 6). It is configured to transmit a rotational force from the rear end side of the crank shaft 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) which is a connecting portion of the cylinder block 6 with the flywheel housing 7 and is arranged on the right side surface side of the cylinder block 6, and is sucked by the cylinder block 6. It is supplied to each lubricating portion of the diesel engine 1 via an oil cooler 13 and an oil filter 14 arranged on the right side surface. The lubricating oil supplied to each lubricating portion is then returned to the oil pan 11. The oil pump (not shown) is configured to be driven by the rotation of the crank shaft 5.

A fuel supply pump 15 for supplying fuel is attached to a 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. The common rail 16 is fixed to the side surface of the cylinder block 6 on the lower side of the intake manifold 3 of the cylinder head 2 and is arranged above the fuel supply pump 15. On the upper surface of the cylinder head 2 covered with the head cover 18, each injector (not shown) for four cylinders having an electromagnetic open / close control type fuel injection valve is provided.

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

A blow-by gas reduction device that takes in blow-by gas leaked from the combustion chamber of the diesel engine 1 to the upper surface side of the cylinder head 2 on the upper surface of the head cover 18 that covers the intake valve and the exhaust valve (not shown) provided on the upper surface of the cylinder head 2. 19 is provided. The blow-by gas outlet of the blow-by gas reduction device 19 is communicated with the intake portion of the two-stage turbocharger 30 via the reduction hose 68. The blow-by gas from which the lubricating oil component has been removed in the blow-by gas reducing device 19 is reduced to the intake manifold 3 via the two-stage turbocharger 30.

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

A cooling water pump 21 for lubricating cooling water is arranged below the cooling fan 9 at a portion on the left side of the rear surface of the cylinder block 6. The rotation of the crank shaft 5 drives the cooling water pump 21 together with the cooling fan 9 via the cooling fan driving V-belt 10. The cooling water in the radiator (not shown) mounted on the work vehicle is supplied to the cooling water pump 21 by driving the cooling water pump 21. Then, 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 surface of the cylinder block 6 at the same height as the cooling water pump 21. It is fixed in. On the other hand, the cooling water outlet pipe 23 that communicates with the cooling water inlet of the radiator is fixedly installed above the rear surface of the cylinder head 2. The cylinder head 2 has a cooling water drainage portion 35 projecting from the rear of the intake manifold 3, and a 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 main body case) 25 of an EGR device 24 (exhaust gas recirculation device) described later. The fresh air (external air) sucked into the air cleaner is dust-removed and purified by the air cleaner, then sent to the intake manifold 3 via the collector 25, and supplied to each cylinder of the diesel engine 1. In the embodiment, the collector 25 of the EGR device 24 is integrally molded with the cylinder head 2 and connected to the right side of the intake manifold 3 forming 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, as will be described later, the collector 25 of the EGR device 24 is connected to the air cleaner via an intercooler (not shown) and a two-stage turbocharger 30.

The EGR device 24 is a collector 25 as a relay line that mixes the 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 exhaust gas to the intake manifold 3. To the intake throttle member 26 that communicates the collector 25 to the air cleaner, the recirculation exhaust gas pipe 28 that is a part of the recirculation pipeline connected to the exhaust manifold 4 via the EGR cooler 27, and the recirculation exhaust gas pipe 28. It has an EGR valve member 29 through which the collector 25 is communicated.

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 in the cylinder head 2. In the EGR device 24, the collector 25 is connected to the intake manifold 3 on the right side surface of the cylinder head 2, and the EGR gas inlet of the recirculation exhaust gas pipe 28 is connected to and fixed to the front portion of the intake manifold 3 on the right side surface of the cylinder head 2. Cylinder. Further, the EGR valve member 29 and the intake throttle member 26 are connected to the front and rear of the collector 25, respectively, and the EGR gas outlet of the 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 is fixed to the cylinder head 2.
The cooling water and the EGR gas flowing inside flow in and out of the EGR cooler 27, and the EGR gas is cooled in the EGR cooler 27. The front side surface of the cylinder head 2 projects EGR cooler connecting pedestals 33 and 34 connecting the EGR coolers 27 to the left and right positions thereof, and the EGR cooler 27 is connected to the connecting pedestals 33 and 34. That is, the EGR cooler 27 is arranged above the flywheel housing 7 and at the front position 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 turbocharger 30 is arranged on the side of the exhaust manifold 4 (on the left side in the embodiment). The two-stage turbocharger 30 includes a high-pressure turbocharger 51 and a low-pressure turbocharger 52. The high-pressure turbocharger 51 has a high-pressure turbine 53 having a built-in turbine wheel (not shown) and a high-pressure compressor 54 having a built-in blower wheel (not shown), and the low-pressure turbocharger 52 has a turbine wheel (not shown). It has a low-pressure turbine 55 with a built-in blower wheel and a low-pressure compressor 56 with a built-in blower wheel (not shown).

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

The high-pressure turbocharger 51 is connected to the exhaust outlet 58 of the exhaust manifold 4 and fixed to the left side of the exhaust manifold 4, while the low-pressure turbocharger 52 passes through the high-pressure exhaust gas pipe 59 and the low-pressure fresh air passage pipe 65. It is connected to the high-pressure turbocharger 51 and fixed above the exhaust manifold 4. That is, the high-pressure turbocharger 51 having a small diameter and the exhaust manifold 4 are arranged side by side below the low-pressure turbocharger 52 having a large diameter, so that the two-stage turbocharger 30 is placed on the left side surface of the exhaust manifold 4. And are arranged so as 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 in a rear view (front view).

Next, the configuration of the cylinder head 2 will be described below with reference to FIGS. 9 to 16. As shown in FIGS. 9 to 16, the cylinder head 2 has a plurality of intake flow paths 36 for introducing fresh air into a plurality of intake ports (not shown) and a plurality of exhaust flow paths for drawing exhaust gas from the plurality of exhaust ports. 37 is formed. An intake manifold 3 that gathers a plurality of intake flow paths 36 is integrally formed on the right side portion of the cylinder head 2. By integrally configuring the cylinder head 2 and the intake manifold 3, it is possible to improve the gas sealing property from the intake manifold 3 to the intake flow path 36 and to increase the rigidity of the cylinder head 2.

In the cylinder head 2, the exhaust manifold 4 is connected to the left side surface opposite to the right side surface on which the intake manifold 3 is configured, and the EGR cooler 27 is connected to the front side surface (side surface on the flywheel housing 7 side) adjacent to the left and right side surfaces. Will be done. Then, a connecting pedestal (EGR cooler connecting pedestal) 33, 34 connected to the EGR cooler 27 is formed so as to project from the front side surface of the cylinder head 2, and an EGR gas flow path (EGR gas relay flow path) is formed in the connecting pedestal 33, 34. 31 and 32 and cooling water flow paths (cooling water relay flow paths) 38 and 39 are formed.

By configuring the EGR gas relay flow paths 31 and 32 and the cooling water flow paths 38 and 39 on the connecting pedestals 33 and 34 to which the EGR cooler 27 is connected, the cooling water piping and the EGR are connected between the EGR cooler 27 and the cylinder head 2. There is no need to install gas piping. Therefore, it is not affected by the expansion and contraction of the pipe due to EGR gas and cooling water, and not only the sealing property at the connecting portion with the EGR cooler 27 can be ensured, but also the resistance to external fluctuation elements due to heat, vibration, etc. (structural stability). In addition to improving the property), it can be configured compactly.

The cylinder head 2 is provided with an upstream EGR gas relay flow path 31 that communicates from the front portion of the left side surface to the front side surface, and the EGR gas outlet 41 provided on the front end side of the exhaust manifold 4 is the upstream side EGR gas relay flow path 31. It communicates with. Further, the cylinder head 2 is provided with a downstream EGR gas relay flow path 32 communicating from the front portion on the right side surface (front of the intake manifold 3) to the front side surface, and the EGR gas inlet of the recirculation exhaust gas pipe 28 is the downstream side EGR. It communicates with the gas relay flow path 32. The cylinder head 2 includes EGR cooler connecting pedestals 33 and 34 having both left and right edge sides (front left corner portion and front right corner portion of the cylinder head 2) projecting forward on the front side surface thereof. An upstream EGR gas relay flow path 31 is provided in the connecting pedestal 33, and a downstream EGR gas relay flow path 32 is provided in the connecting pedestal 34.

The 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 near the rear of the right side surface of the cylinder head 2 (cooling fan 9 side), and is configured such that the lower portion of the right side surface of the cylinder head 2 is projected to the right side and is located at the center position in the front and rear thereof. It has an intake inlet 40. The intake outlet 83 in the collector 25 of the EGR device 24 is connected to the intake inlet 40 of the intake manifold 3 projecting from the right side surface of the cylinder head 2, and the EGR device 24 is fixed to the right side of the cylinder head 2.

A connecting pedestal 34 connected to the EGR cooler 27 is projected forward on the front right side of the cylinder head 2 (flywheel housing 7 side), and a downstream EGR gas relay flow path 32 is projected on the right side of the connecting pedestal 34. EGR gas outlet is open. Then, by connecting one end of the recirculation exhaust gas pipe 28 of the EGR device 24 to the right side surface of the connecting pedestal 34, the collector 25 of the EGR device 24 is connected to the recirculation exhaust gas pipe 28 and the EGR valve member 29. It communicates with the downstream EGR gas relay flow path 32 in the cylinder head 2.

Behind the right side surface (cooling fan 9 side) of the cylinder head 2, a cooling water drainage section (thermostat case) 35 having an upper surface open and communicating with a cooling water outlet pipe (thermostat cover) 23 is projected rearward. A thermostat (not shown) is installed inside it. Since the cooling water drainage section 35 is configured by being 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 attached to the lower side of the cooling water drainage section 35. The length of the diesel engine 1 in the front-rear direction can be shortened. The cooling water drainage section 35 also protrudes from the right side surface of the cylinder head 2, and the intake manifold 3 and the cooling water drainage section 35 are provided side by side on the right side surface of the cylinder head 2.

A connecting pedestal 33 connected to the EGR cooler 27 is projected forward on the front left side of the cylinder head 2 (flywheel housing 7 side), and an upstream EGR gas relay flow path 31 is projected on the left side of the connecting pedestal 33. 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 flow path 31 and the exhaust outlets of the plurality of exhaust flow paths 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 communicating with the upstream EGR gas relay flow path 31 and an exhaust inlet communicating with a plurality of exhaust flow paths 37 on the right side surface serving as a connecting surface with the left side surface of the cylinder head 2. 42 and 42 are open side by side in the front-rear direction. 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 is easily airtight (gas) by narrowing one gasket 45. Sealability) can be ensured.

The exhaust manifold 4 is internally provided with an exhaust collecting portion 43 communicating with the EGR gas outlet 41 and the exhaust inlet 42 so that the front-rear direction is the longitudinal direction, and the exhaust is exhausted on the rear left side surface of the exhaust manifold 4. The exhaust outlet 44 communicating with the collecting portion 43 is opened. In the exhaust manifold 4, when the exhaust gas from the exhaust flow path 37 of the cylinder head 2 flows into the exhaust collecting portion 43 through the exhaust inlet 42, a part of the exhaust gas becomes EGR gas and upstream of the cylinder head 2 from the EGR gas outlet 41. It flows into the side EGR gas relay flow path 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 connecting 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 connecting pedestal 33 is provided with an upstream EGR gas relay flow path 31 that allows the EGR gas flow paths of the exhaust manifold 4 and the EGR cooler 27 to communicate with each other. On the other hand, the EGR cooler connecting pedestal 34 is provided with a downstream EGR gas relay flow path 32 for communicating the EGR gas flow paths of the EGR device 24 and the EGR cooler 27, respectively. Further, the EGR cooler connecting pedestal 33 is provided with a downstream cooling water flow path 38 in which cooling water is discharged from the EGR cooler 27. On the other hand, the EGR cooler connecting 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.

By making the EGR cooler connecting pedestals 33 and 34 projecting, the EGR gas piping for communicating the exhaust manifold 4, the EGR cooler 27, and the EGR device 24 is not required, and the connecting points in the EGR gas flow path are eliminated. It will be less. Therefore, in the diesel engine 1 that reduces NOx by EGR gas, not only EGR gas leakage can be reduced, but also deformation due to stress change due to expansion and contraction of the pipe can be suppressed. Further, in order to form the EGR gas relay flow paths 31 and 32 and the cooling water flow paths 38 and 39 on the EGR cooler connecting pedestals 33 and 34, the shapes of the flow paths 31, 32, 38 and 39 configured in the cylinder head 2 are formed. Since the above is simplified, the cylinder head 2 can be easily cast without using a complicated core.

Since the EGR cooler connecting pedestal 33 on the intake manifold 3 side and the EGR cooler connecting pedestal 34 on the exhaust manifold 4 side are separated from each other, mutual influences due to thermal deformation on the connecting pedestals 33 and 34 can be suppressed. Therefore, not only can gas leakage and breakage be prevented at the connecting portion between the EGR cooler connecting pedestals 33 and 34 and the EGR cooler 27, but also the rigidity balance of the cylinder head 2 can be maintained. Further, since the volume on the front side surface of the cylinder head 2 can be reduced, the weight of the cylinder head 2 can be reduced. Further, since the EGR cooler 27 can be arranged so as to be separated from the front side surface of the cylinder head 2 and have a space in front of and behind the EGR cooler 27, cooling air can flow around the EGR cooler 27, so that the EGR cooler 27 can flow. It is possible to increase the cooling efficiency in.

The downstream cooling water flow path 38 and the upstream EGR gas relay flow path 31 are vertically arranged on the EGR cooler connecting pedestal 33, and the downstream side EGR gas relay flow path 32 and the upstream side are arranged on the EGR cooler connecting pedestal 34. The side cooling water flow paths 39 are arranged vertically. The cooling water inlet of the downstream cooling water flow path 38 and the EGR gas inlet of the downstream EGR gas relay flow path 32 are arranged at the same height, while the cooling water outlet of the upstream cooling water flow path 39 and the downstream EGR. The EGR gas outlet of the gas relay flow path 32 is arranged at the same height.

By configuring the EGR gas relay flow paths 31 and 32 and the cooling water flow paths 38 and 39 internally in the EGR cooler connecting pedestals 33 and 34 that are separately and projecting, the heat in both the EGR cooler connecting pedestals 33 and 34 is set. The effect of deformation is mitigated. Further, in the EGR cooler connecting pedestals 33 and 34, the EGR gas flowing through the EGR gas relay channels 31 and 32 is cooled by the cooling water flowing through the cooling water channels 38 and 39, and the thermal deformation itself in the EGR cooler connecting pedestals 33 and 34 itself. Is also suppressed. Further, in each of the EGR cooler connecting pedestals 33 and 34, the EGR gas relay flow paths 31 and 32 and the cooling water flow paths 38 and 39 are arranged so as to replace their respective vertical height positions. Therefore, the heat distribution in the EGR cooler connecting pedestals 33 and 34 is upside down, and the influence of thermal deformation in the height direction in the cylinder head 2 can be reduced.

The cylinder head 2 includes a spacer 46 that is connected to the lower peripheral edge of the head cover 18 by an outer peripheral wall that is erected upward from the upper peripheral edge thereof. The spacer 46 is provided with a plurality of openings 47 on the right side surface, through which the fuel pipe 48 connecting the injector (not shown) provided in the cylinder head 2 and the common rail 16 is passed. ing. By integrally providing the spacer 46 above the cylinder head 2, the rigidity of the cylinder head 2 can be increased, and not only the distortion of the cylinder head 2 itself can be reduced, but also each component connected to the cylinder head 2 can be reduced. Can be supported with high rigidity.

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

In the collector 25, the fresh air flow direction and the EGR gas flow direction intersect at an orthogonal or blunt angle, and the direction in which the mixed gas of the EGR gas and the fresh air is taken into the intake manifold 3 is the fresh air flow direction and the EGR gas. The direction intersects each flow direction. 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 surfaces of the collector 25, and an intake outlet 83 connected to the intake manifold 3 is provided. It is opened on the left side surface of the collector 25. 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 bends in an L shape from the front-rear direction to the vertical direction and flows, while being introduced from the EGR valve member 29 to the EGR gas inlet 82. The EGR gas flows diagonally 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 bends in an L shape from the vertical direction to the left and right direction and flows, and flows into the intake manifold 3 from the intake outlet 83. Since the derivation direction of the mixed gas intersects not only the introduction direction of the fresh air and the introduction direction of the EGR gas but also the flow direction of the fresh air and the EGR gas in the collector 25, the mixed distribution of the EGR gas to the fresh air is changed. Can be made uniform.

As described above, in the collector 25, the EGR gas flow direction with respect to the fresh air flow direction becomes 90 ° or more, and the fresh air flow and the EGR gas flow intersect, so that the mixture distribution of the EGR gas with respect to the fresh air is one. As such, the drift of 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 flow paths 36 in the cylinder head 2 can be made uniform, and the variation 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 achieve clean exhaust gas by refluxing EGR gas without causing a 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 outlet 83. By configuring the collector 25 so that the upper case 84 and the lower case 85 can be vertically divided, a mixing flow path in which the EGR gas flow and the fresh air flow intersect at 90 ° or more can be easily configured in the collector 25. can. Therefore, not only can the collector 25 be made of a highly rigid casting, but also the weight can be reduced by using an aluminum-based casting.

A downstream EGR gas flow path (first EGR gas flow path) 86a, which is a part of the EGR gas flow path 86 through which EGR gas flows, and a mixing chamber 87 for mixing fresh air and EGR gas are provided in the upper case 84. ing. An upstream EGR gas flow path (second EGR gas flow path) 86b that communicates the downstream side EGR gas flow path 86a and the EGR gas inlet 82, and a mixed gas in which fresh air and EGR gas are mixed are introduced from the mixing chamber 87 to an intake manifold. The mixed gas flow path 88 to be supplied to 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. Therefore, in the mixing chamber 87, the fresh air flowing from the fresh air inlet 81 and the lower case 85 are provided. The EGR gas flowing from the EGR gas flows so as to intersect each other, and the fresh air and the EGR gas are efficiently mixed. Further, by providing the intake outlet 83 in the lower case 85, the fresh air flowing into the upper case 84 tends to flow toward the lower case 85, so that the new EGR gas flowing toward the upper case 84 is new. Mixing into the air is homogenized. Further, each of the EGR gas flow path 86, the mixing chamber 87, and the mixed gas flow path 88 can be compactly configured in the collector 25, and the size of the collector 25 can be reduced.

In a plan view, the downstream EGR gas flow path 86a is offset and connected to the central axis of the mixing chamber 87 on the side surface (left side) opposite to the side surface (left side) provided with the intake outlet 83, and downstream. The side EGR gas flow path 86a and the upstream side EGR gas flow path 86b are communicated with each other, and the EGR gas flow path 86 is formed in a spiral shape. That is, the EGR gas flow path 86 formed by the downstream side EGR gas flow path 86a and the upstream side EGR gas flow path 86b is curved so as to bulge to the opposite side (right side) of the intake outlet 83 in a plan view. The bottom of the upstream EGR gas flow path 86b is composed of an inclined surface (an inclined surface toward the rear upper side) from the EGR gas inlet 82 toward the upper case 84.

In the mixing chamber 87, the communication point with the EGR gas flow path 86 is on the opposite side of the intake outlet 83, so that the EGR gas flowing into the mixing chamber 87 is guided by the flow of fresh air and reaches the intake outlet 83. Therefore, the EGR gas can be uniformly mixed with the fresh air. Further, 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 mixing gas flow path 88, the fresh air and the EGR gas flow into each other in the mixing chamber 87. The EGR gas flows smoothly as if colliding with each other.

Further, since the EGR gas flows along the spiral EGR gas flow path 86, the EGR gas becomes a swirling flow forming a clockwise vortex and flows into the mixing chamber 87. Since the EGR gas turbulent in this way flows in the direction opposite to the flow of the fresh air gas, the EGR gas flows into the mixing chamber 87 and at the same time, the fresh air flowing inside is smoothly mixed. Therefore, in the collector 25, the fresh air and the EGR gas can be efficiently mixed while stirring before being sent to the intake manifold 3 (the EGR gas can be smoothly dispersed in the mixed gas), and the gas mixed state in the collector 25. It is possible to suppress the variation (unevenness) of the gas more reliably. As a result, the mixed gas with less unevenness can be distributed to each cylinder of the diesel engine 1 to suppress the variation in the amount of EGR gas between the cylinders, so that the generation of black smoke can be suppressed and the combustion state of the diesel engine 1 can be suppressed. The amount of NOx can be reduced while maintaining good quality. Further, by making the EGR gas flow path 86 spiral, the EGR gas flowing into the mixing chamber 87 is provided with sufficient swirlability, 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 together to provide openings (fresh air inlet 81, EGR gas inlet 82, and intake outlet 83) in three directions (front-rear direction and left direction). ) Is configured. In the upper case 84, the fresh air outlet of the intake throttle member 26 is bolted to the rear flange 84b that opens the fresh air inlet 81. The intake throttle member 26 adjusts the amount of fresh air supplied to the collector 25 by adjusting the opening degree of the intake valve (butterfly valve) 26a inside the intake throttle member 26.

In the lower case 85, the EGR gas outlet of the EGR valve member 29 is bolted to the front flange 85b that opens the EGR gas inlet 82 via a rectangular tubular relay flange 89. The EGR valve member 29 adjusts the supply amount of EGR gas to the collector 25 by adjusting the opening degree of the EGR valve (not shown) inside the EGR valve member 29. The reed valve 90 inserted into the EGR gas inlet 82 is fixed inside the front flange 85b of the lower case 85. Then, the relay flange (seat) 89 bolted to the front flange 85b covers the front of the reed valve 90, so that the collector 25 internally installs the reed valve 90 on the EGR gas inlet 82 side of the EGR gas flow path 86. do.

The relay flange 89 has an EGR gas outlet 89a that communicates with the EGR gas inlet 82 opened on the rear surface connected to 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 is merged with the EGR gas inlets at the upper and lower valve connecting seats 89b and 89c, and flows from the EGR gas inlet 82 to the EGR gas flow path 86 in the collector 25 via the reed valve 90.

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

In the EGR valve member 29, the EGR gas cooled by the EGR cooler 27 passes through the downstream side EGR gas relay flow path 32 and the recirculation exhaust gas pipe 28 of the EGR cooler connecting pedestal 34, and the EGR gas inlet of the inlet side flange 29c. The EGR gas is distributed up and down through the EGR gas flow path 29f of the valve body 29e. Then, the EGR gas flowing up and down by 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 in 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 flat plate-shaped rib 28b projecting from the inner peripheral side of the outer wall of the gas pipe portion 28a. Further, the recirculation exhaust gas pipe 28 is provided with an outlet side flange 28c connected to the inlet side flange 29c of the EGR valve member 29 at one end (rear end) of the gas pipe portion 28a, while is connected to the right side surface of the EGR cooler connecting pedestal 34. The 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 to have a short collector 25, the distance between the EGR valve member 29 and the intake throttle member 26 can be shortened, and as a result, the front-rear length of the EGR device 24 can be shortened. Further, since the EGR valve member 29 has the 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, so that the vertical height of the EGR device 24 can be set. Not only can the throttle be made low, but the left-right width of the EGR device 24 can be made narrow. Therefore, since the EGR device 24 is compactly configured, not only can it be easily connected by adjusting with the recirculation exhaust gas pipe 28 in the right direction of the cylinder head 2 integrally formed with the intake manifold 3, but also the diesel engine 1 can be connected. Contributes to miniaturization.

Since the recirculation exhaust gas pipe 28 has a configuration in which flat plate-shaped ribs 28b are connected so as to connect both ends of the gas pipe portion 28a, the recirculation exhaust gas pipe 28 is configured to have high rigidity and a cylinder head. The support strength on the front end side of the EGR device 24 is also increased with respect to 2. Further, since the recirculation exhaust gas pipe 28 is configured to have flat plate-shaped ribs 28b along the EGR gas flow path 28f in the gas pipe portion 28a, the ribs 28b increase the heat dissipation area in the gas pipe portion 28a. Therefore, the cooling effect of the EGR gas flowing through the EGR gas flow path 28f is enhanced. As a result, it contributes to the cooling of the mixed gas purified by the EGR device 24, and has the effect of facilitating the maintenance of the NOx amount reduction effect of the mixed gas in an appropriate state.

Next, the configuration of the EGR cooler 27 will be described below with reference to FIGS. 9 to 11, FIGS. 13 to 16, and FIGS. 20 to 21. As shown in FIGS. 9 to 11, FIGS. 13 to 16, and FIGS. 20 to 21, the EGR cooler 27 exchanges heat with the heat exchange unit 91 in which the cooling water flow path and the EGR gas flow path are alternately laminated. A pair of left and right flange portions 92, 93 provided at both left and right ends on one side surface of the portion 91 are provided. The cooling water outlet 94 and the cooling water inlet 95 are separately provided on the left and right flange portions 92 and 93, while the EGR gas inlet 96 and the EGR gas outlet 97 are separately provided on the left and right flange portions 92 and 93. .. Further, the 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 each of the pair of left and right flange portions 92 and 93 with an opening portion for cooling water and an opening portion for EGR gas, not only can the flange portions 92 and 93 be configured with common members, but also the flanges can be configured. The material cost for parts 92 and 93 can be suppressed. Further, since the flange portions 92 and 93 are configured by drilling through holes 94 to 97 for cooling water and EGR gas in a flat plate for connecting to the cylinder head 2, it is easy to manufacture in the EGR cooler 27. Is. Further, since the connecting portion between the flange portions 92 and 93 and the heat exchange portion 91 can be configured to the 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 the cooling effect.

The EGR cooler 27 has a structure in which the flange portions 92 and 93 are projected from the rear surface of the heat exchange portion 91, so that a space is formed between the heat exchange portion 91 and the cylinder head 2. Therefore, in the EGR cooler 27, a wide range of the front and rear surfaces of the heat exchange unit 91 is exposed to the outside air, and heat is dissipated from the heat exchange unit 91, so that the cooling effect of the EGR gas in the EGR cooler 27 is enhanced. Therefore, the number of layers in the heat exchange unit 91 can be reduced and the front-rear length of the EGR cooler 27 can be shortened as compared with the case where the front surface of the rear surface of the heat exchange unit 91 is attached, so that the diesel engine 1 can be downsized. ..

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. The left flange portion 92 is provided with the cooling water outlet 94 and the EGR gas inlet 96 at the top and bottom, while the right flange portion 93 is provided with the EGR gas outlet 97 and the cooling water inlet 95 at the top and bottom. .. Further, 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 and 93 of the EGR cooler 27 are connected to each of the EGR cooler connecting pedestals 33 and 34 formed so as to project from the front side surface of the cylinder head 2. The upstream EGR gas relay flow path 31 and the downstream side cooling water relay flow path 38 in the left EGR cooler connecting pedestal 33 communicate with the EGR gas inlet 96 and the cooling water outlet 94 of the left side flange portion 92, respectively, and the right side EGR cooler. The downstream EGR gas relay flow path 32 and the upstream cooling water relay flow path 39 in the connecting pedestal 34 communicate with the EGR gas outlet 97 and the cooling water inlet 95 of the right side flange portion 93, respectively.

The EGR gas relay flow paths 31 and 32 and the cooling water flow paths 38 and 39 are configured on the connecting pedestals 33 and 34 to which the flange portions 92 and 93 of the EGR cooler 27 are connected, and the EGR gas inlet 96 and the outlet are connected to the flange portions 92 and 93. The 97 is communicated with the cooling water outlet 94 and the inlet 95. Therefore, it is not necessary to provide a cooling water pipe and an EGR gas pipe between the EGR cooler 27 and the cylinder head 2. Therefore, the sealing property at the connecting portion between the EGR cooler 27 and the cylinder head 2 can be ensured without being affected by the expansion and contraction of the pipe due to the EGR gas and the cooling water, and the EGR cooler 27 is externally affected by heat, vibration, or the like. The resistance to the variable elements of the cylinder head 2 is improved, and the cylinder head 2 can be compactly installed.

Since the flange portion 92 is provided with the cooling water outlet 94 and the EGR gas inlet 96 on the upper and lower sides, and the flange portion 93 is provided with the EGR gas outlet 97 and the cooling water inlet 95 on the upper and lower sides, the flange portions 92 and 93 have the same shape. However, they are flipped upside down and attached to the heat exchange unit 91. Therefore, the types of parts constituting the EGR cooler 27 can be reduced, the assembleability of the EGR cooler 27 is improved, and the cost of parts is reduced.

Further, 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 the distortion due to thermal deformation in each of the flange portions 92 and 93 is suppressed, but also the flange portions 92 and 93 are configured as separate bodies, and the influence of mutual thermal deformation is small, so that the EGR cooler 27 is damaged or damaged. You can prevent breakdowns.

In the EGR cooler 27, the cooling water outlet 94 and the cooling water inlet 95 are arranged diagonally, and the EGR gas inlet 96 and the EGR gas outlet 97 are arranged diagonally in the rear view. Since EGR gas and cooling water having different calories are supplied or discharged from diagonal positions, thermal deformation at the connecting portion between the EGR cooler 27 and the cylinder head 2 is alleviated, and bending and loosening of the connecting portion are suppressed. can. Therefore, not only can the leakage of EGR gas and cooling water in the EGR cooler 27 and the cylinder head 2 be prevented, but also a decrease in the connection strength can be prevented.

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

Since the flange portions 92 and 93, which are separate bodies, are connected to the connecting pedestals 33 and 34 of the cylinder head 2 via the gasket 98, tension acts on the gasket 98 due to thermal deformation at the connecting portion with the cylinder head 2. .. Therefore, the sealing property (sealing property) by the gasket 98 is improved at the connecting portion of each of the EGR gas inlet 96 and the EGR gas outlet 97, and the EGR gas leaking back and forth between the cylinder head 2 and the EGR cooler 27 is prevented from leaking. Can be prevented. Further, since the O-ring 99 is embedded in the space composed of the cooling water inlet and the cooling water outlet in the connecting pedestals 33 and 34 of the cylinder head 2 and the rear end faces of the flange portions 92 and 93, the cooling water flows. At that time, the communicating portions of the connecting pedestals 33 and 34 and the flange portions 92 and 93 come into contact with the O-ring 99, so that the sealing property (sealing property) of the connecting portions at the cooling water inlets and outlets 94 and 95 can be ensured. Therefore, even if the EGR cooler 27 that performs the inflow and outflow of the liquid and the gas is connected to the cylinder head 2, the sealing property of the liquid and the gas can be ensured, and the leakage of the EGR gas and the cooling water can be prevented.

A through hole 100 for bolt fastening is formed 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 upper and lower sides and the left side, and the right side flange portion 93 has five through holes 100 on the upper and lower sides and the right side. Therefore, the left side flange portion 92 is provided with a through hole 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, so that the cylinder head When bolted to the connecting pedestal 33 of No. 2, the sealing property at the cooling water outlet 94 and the EGR gas inlet 96 is ensured. Similarly, the right side flange portion 93 is provided with through holes 100 on the lower side of the cooling water inlet 95, the upper side of the EGR gas outlet 97, and the right side between the cooling water inlet 95 and the EGR gas outlet 97, respectively. When bolted to the connecting pedestal 34 of the head 2, the sealing property at the cooling water inlet 95 and the EGR gas outlet 97 is ensured.

The gasket 98 is configured by laminating two plates 98a and 98b provided with through holes 101 to 103, and the EGR gas passes through the through hole (through hole for EGR gas) 101 to pass through the through hole (cooling water). Cooling water passes through the through hole 102, and the 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 area of the cooling water inlets / outlets 94 and 95. Is also configured to be wide.

The gasket 98 bends the inner peripheral edge of the front side plate 98a in the EGR gas through hole 101 to the front side, while the inner peripheral edge of the rear side plate 98b in the EGR gas through hole 101 bends to the rear side. By bonding 98a and the rear side plate 98b by welding, 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 to be curved 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 end faces of the connecting pedestals 33, 34 and the flange portions 92, 93, respectively. Therefore, sufficient airtightness can be ensured.

The gasket 98 is configured such that the opening of the cooling water through hole 102 is wider than the cooling water inlet / outlet ports 94 and 95, so that the O-ring 99 is inserted into the cooling water through hole 102. That is, the communication portion between the cooling water inlet / outlet ports 94 and 95 of the flange portions 92 and 93 and the cooling water relay flow paths 38 and 39 in the connecting pedestals 33 and 34 is fitted into the cooling water through hole 102 of the gasket 98. It is sealed by an O-ring 99.

Further, the connecting pedestals 33 and 34 of the cylinder head 2 are larger than the flow path diameters of the cooling water relay flow paths 38 and 39 in the connecting pedestals 33 and 34 by opening the cooling water inlets and outlets 94 and 95 with steps. The O-ring 99 is fitted to the outer peripheral side of the cooling water relay flow paths 38 and 39 with respect to the cooling water inlets and outlets 94 and 95 of the connecting pedestals 33 and 34. That is, the O-ring 99 is inserted into the gasket 98, fitted to the stepped portion of the cooling water inlet / outlet ports 94, 95 in the connecting pedestals 33, 34, and narrowed by the connecting pedestals 33, 34 and the flange portions 92, 93. Will be done. Therefore, when the cooling water passes through the inside of the O-ring 99 made of the elastic material, the O-ring 99 is deformed so as to spread outward, and is in close contact with the connecting pedestals 33, 34 and the flange portions 92, 93. , Ensuring the sealing performance of the cooling water.

The ring-shaped O-ring 99 has a shape in which the inner peripheral portion bulges back and forth, and the front and rear edges of the inner peripheral portion are moved back and forth by being pressed by the cooling water passing through the inner peripheral portion of the O-ring 99. It deforms to protrude. As a result, the inner peripheral portion of the O-ring 99 is in close contact with the connecting pedestals 33, 34 and the flange portions 92, 93, so that the sealing property of the cooling water at the connecting 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 back and forth and has a concave portion on the inner peripheral surface thereof. That is, by forming the inner peripheral surface of the O-ring 99 with a Y-shaped cross section curved back and forth, the front and rear edges of the inner peripheral portion are pressed by the cooling water passing through the inner peripheral portion of the O-ring 99. Is further projected back and forth to improve the adhesion between the inner peripheral portion of the O-ring 99 and the connecting pedestals 33, 34 and the flange portions 92, 93, and therefore, cooling at the connecting portion between the cylinder head 2 and the EGR cooler 27. The sealing property of water can be improved.

Next, the configuration of the two-stage turbocharger 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 turbocharger 30 compresses the fresh air flowing into the intake manifold 3 of the cylinder head 2 by the fluid energy of the exhaust gas discharged from the exhaust manifold 4. The two-stage turbocharger 30 is composed of a high-pressure turbocharger 51 connected to the exhaust manifold 4 and a low-pressure turbocharger 52 connected to the high-pressure turbocharger 51.

The high-pressure turbocharger 51 is arranged on the left side of the exhaust manifold 4, and the low-pressure turbocharger 52 is arranged above the exhaust manifold 4. That is, while the small-capacity high-pressure turbocharger 51 is arranged facing the exhaust manifold 4, the large-capacity low-pressure turbocharger 52 is projected to the left side with respect to the cylinder head 2 and is installed above the exhaust manifold 4. Is placed in. Therefore, not only the exhaust manifold 4 and the two-stage turbocharger 30 can be compactly arranged in the space on the left side of the cylinder head 2, but also the uppermost position of the two-stage turbocharger 30 is lower than the uppermost position of the diesel engine 1. Can be a position. Therefore, not only can it contribute to the miniaturization of the diesel engine 1, but also the low-pressure turbocharger 52 can be arranged closer to the cylinder head 2 to fix the two-stage turbocharger 30 with high rigidity.

The high-pressure turbocharger 51 includes a high-pressure turbine 53 that communicates with the exhaust outlet 44 of the exhaust manifold 4, and a high-pressure compressor 54 that supplies 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 and the like) of the intake throttle member 26 via an intercooler (not shown). do. On the other hand, the low-pressure turbocharger 52 is via a low-pressure turbine 55 in which the exhaust inlet of the high-pressure turbine 53 and the exhaust inlet communicate with each other via the exhaust-side relay pipe, and the fresh air inlet and the fresh-air side relay pipe of the high-pressure compressor 54. It is equipped with a low-pressure compressor 56 through which a fresh air outlet communicates, and a low-pressure compressor 56 is arranged above the high-pressure turbine 53, and a high-pressure compressor 54 is arranged on one side in front of and behind the high-pressure turbine 53, while low pressure. A low-pressure turbine 55 is arranged on the front, rear, and other sides of the compressor 56.

The exhaust manifold 4 has an exhaust outlet 44 for discharging exhaust gas open to the left and right sides. The high-pressure turbine 53 opens the exhaust inlet 57 toward the exhaust manifold 4, while opening the exhaust outlet 58 toward the front. Further, in the low pressure turbine 55, the exhaust inlet 60 is opened downward, while the exhaust outlet 61 is opened forward.

The exhaust outlet 44 of the exhaust manifold 4 facing each other and the exhaust inlet 57 of the high-pressure turbine 53 are bolted together by a flange, and the high-pressure turbocharger 51 is fixed on the left side of the exhaust manifold 4. The exhaust outlet 58 of the high-pressure turbine 53 is bolted to one end (rear end) of the L-shaped high-pressure exhaust gas pipe 59 (exhaust side relay pipe) with a flange, while the exhaust inlet 60 of the low-pressure turbine 55 exhausts high pressure. The low-pressure turbocharger 52 is fixed above the high-pressure turbocharger 51 by being bolted 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 coupling to support the high-pressure turbocharger 51 with high rigidity, and then a low-pressure turbine is connected to the upper surface of the high-pressure exhaust gas pipe 59 connected to the front of the high-pressure turbocharger 51 by flange coupling. By connecting 55 by flange coupling, the low-pressure turbocharger 52 can be supported from below by the high-pressure turbocharger 51. Further, since the low-pressure turbocharger 52 is installed near the upper side of the exhaust manifold 4, the center of gravity of the low-pressure turbocharger 52 is located above the connection position between the exhaust manifold 4 and the high-pressure supercharger 51. Become. Therefore, the two-stage turbocharger 30 can be supported with high rigidity and compactly around the diesel engine 1.

The high-pressure compressor 54 opens the fresh air intake port 63 (fresh air inlet) toward the rear, while opening the fresh air supply port 64 (fresh air outlet) downward. On the other hand, the low-pressure compressor 56 is configured to open the fresh air intake port 66 (fresh air inlet) toward the rear, while projecting the fresh air supply port 67 (fresh air outlet) from the left side and then toward the rear. ing. Then, while one end of the 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, other than the low-pressure fresh air passage pipe 65. 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 U-shaped low-pressure fresh air passage pipe 65 at the rear, and are supported by the exhaust manifold 4 with high rigidity to the high-pressure supercharger 51 at the front portion of the low-pressure supercharger 52. Can be fixed. The low-pressure compressor 56 extends the fresh air intake port 66 and the fresh air supply port 67 in the same direction (rearward), and communicates with an air cleaner (not shown) with a supply pipe 62 and a low-pressure fresh air passage pipe 65, respectively. Since the structure is easy to connect, it is possible to improve the workability of assembly.

The low-pressure fresh air passage pipe 65 has 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 composed of a resin tube 65b to be communicated with. As a result, in the low-pressure fresh air passage pipe 65, the metal pipe 65a is fixed to the high-pressure compressor 54 with high rigidity, while the resin pipe 65b reduces the assembly error between the low-pressure compressor 56 and the metal pipe 65a and allows them to communicate with each other. can.

Since the fresh air supply port 67 of the low-pressure compressor 56 is configured to project from the left side surface of the low-pressure compressor 56 to the left side and then 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 generated compressed air 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 reduction device 19 that takes in blow-by gas is installed on the cylinder head 2. The blow-by gas reduction device 19 is placed and fixed on the upper surface of the 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 reduction device 19 is connected to a supply pipe 62 connected to a fresh air intake port 66 (fresh air inlet) of the low-pressure compressor 56 via a reduction hose 68. Further, the 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 turbocharger 52, which is a component on the upper side of the two-stage turbocharger 30, and is arranged closer to the cylinder head 2, a blow-by gas reduction device arranged above the cylinder head 2 The distance between 19 and the air supply pipe 62 can be reduced. Therefore, the reduction hose 68 can be shortened to prevent freezing in the reduction hose 68 in a low temperature environment. The air supply pipe 62 is arranged in the space surrounded by the low-pressure fresh air passage pipe 65 and the cylinder head 2, and it is possible to prevent damage due to external force at the connecting portion between the resin pipe connected to the air cleaner (not shown). ..

The high-pressure turbocharger 51 projects a fresh air supply port 64 that opens downward on the cylinder head 2 side on the lower surface of the high-pressure compressor 54. The high-pressure compressor 54 is connected to a high-pressure fresh air passage pipe 71 that is communicated 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 that opens toward the left side is provided. By connecting the high-pressure fresh air passage pipe 71 to the rear left side 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 to each other. .. For this reason, the piping of the cooling water pipe and the high-pressure fresh air passage pipe 71 can be centralized, which not only simplifies the piping structure on the machine side on which the diesel engine 1 is mounted, but also facilitates assembly work and maintenance work. Can be configured in a state.

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

A turbine exhaust hole 58a for discharging exhaust gas that rotates a turbine wheel (not shown), a bypass hole 58b for communicating the exhaust inlet 57 and the exhaust outlet 58, and a bypass hole 58b are provided at the exhaust outlet 58 of the high-pressure turbine 53. A wastegate valve 69 that opens and closes is provided. By arranging the turbine exhaust hole 58a and the bypass hole 58b side by side at the exhaust outlet 58 of the high-pressure turbine 53, it is possible to set whether or not the compression operation by the high-pressure supercharger 51 is possible according to the rotation speed of the diesel engine 1. Therefore, the exhaust energy can be efficiently used in the two-stage turbocharger 30, the amount of fresh air supplied to the combustion chamber can be stabilized, the engine output can be increased, and the amount of black smoke emitted can be reduced.

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 that connects the high-pressure turbine 53 and the low-pressure turbine 55 is used. The piping may be sufficient, and the bypass piping for communicating the exhaust manifold 4 and the low-pressure turbine 55 becomes unnecessary. Therefore, not only the piping structure in the two-stage turbocharger 30 can be simplified, but also the space around the two-stage turbocharger 30 can be expanded. The hydraulic pump (not shown) can be installed side by side with the engine starting starter 20.

In the high-pressure turbocharger 51, a high-pressure hydraulic oil supply pipe 73 and a high-pressure hydraulic oil return pipe 74 are connected above and below the center housing 72 which is a connecting portion between the high-pressure turbine 53 and the high-pressure compressor 54. Similarly, in the low-pressure turbocharger 52, a low-pressure hydraulic oil supply pipe 76 and a low-pressure hydraulic oil return pipe 77 are connected above and below the center housing 75, which is a connecting portion between the low-pressure turbine 55 and the low-pressure compressor 56.

The lower end of the high-pressure hydraulic oil supply pipe 73 is connected to the connecting member 78 installed on the left side surface of the cylinder block 6, while the upper end is connected to the upper surface of the center housing 72 of the high-pressure turbocharger 51. On the upper surface of the center housing 72 of the high-pressure turbocharger 51, a connecting joint 79 for communicating 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 is installed. 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 turbocharger 52. As a result, the hydraulic oil flowing through the oil passage in the cylinder block 6 is supplied to the center housing 72 of the high-pressure turbocharger 51 through the high-pressure hydraulic oil supply pipe 73, and the high-pressure hydraulic oil supply pipe 73 and the low-pressure operation. It is supplied to the center housing 75 of the low-pressure turbocharger 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 turbocharger 51, and is piped so as to bypass the rear of the exhaust outlet 44 of the exhaust manifold 4. Further, the low-pressure hydraulic oil supply pipe 76 is piped in an L shape along the upper surface of the high-pressure turbocharger 51 and the center housing 75 of the low-pressure turbocharger 52. In this way, the hydraulic oil supply pipes 73 and 76 are shortened, and the hydraulic oil is efficiently supplied to the two-stage turbocharger 30 by piping so as to surround the two-stage turbocharger 30, which is a highly rigid component. At the same time, it is possible to prevent damage to the hydraulic oil supply pipes 73 and 76 due to external force.

One end (lower end) of the high-pressure hydraulic oil return pipe 74 is connected to the tip (left end) of the connecting joint 80 installed on the left side surface of the cylinder block 6, while the other end (upper end) is the high-pressure turbocharger 51. It is connected to the lower surface of the center housing 72 of. Further, the low pressure hydraulic oil return pipe 77 has one end (lower end) connected to the branched upper end of the connecting joint 80, while the other end (upper end) is connected to the lower surface of the center housing 75 of the low pressure turbocharger 52. .. Therefore, the hydraulic oil flowing through the high-pressure turbocharger 51 and the low-pressure turbocharger 52 is merged from the low-pressure hydraulic oil return pipes 74 and 77 below the center housings 72 and 75 by the connecting joint 80, and the oil in the cylinder block 6 is used. Returned to the road.

The high-pressure hydraulic oil return pipe 74 is piped so as to bypass 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 turbocharger 51, and is piped so as to bypass the front of the exhaust outlet 44 of the exhaust manifold 4. In this way, the hydraulic oil return pipes 74 and 77 are shortened, and the hydraulic oil is efficiently supplied to the two-stage turbocharger 30 by piping so as to surround the two-stage turbocharger 30, which is a highly rigid component. At the same time, it is possible to prevent damage to the hydraulic oil return pipes 74 and 77 due to external force.

Next, the 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, the cooling water pump mounting portion 319 and the cooling water inlet pipe 22 to which the cooling water pump 21 (see FIG. 2 and the like) are mounted are located on the left side surface of the cylinder block 6 near the rear side surface. An inlet pipe mounting seat 320 to which (see FIG. 3 and the like) is mounted is provided so as to project. The cooling water pump mounting portion 319 and the inlet pipe mounting seat 320 are integrally molded with the cylinder block 6. Further, the portion on the rear side surface side 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 are projected in a direction away from the crank shaft 5, and the rigidity, strength, and cooling efficiency of the cylinder block 6 can be improved.

A cooling water pump 21 for cooling water circulation is bolted to the rear side surface 312 of the cylinder block 6 and the 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 have five through bolt holes provided on the peripheral edge of the base plate portion 331 and the 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 fastened, respectively, and the peripheral edges are closely fixed to each other.

Further, in the cooling water pump 21, mounting bolts 348 are inserted into the through holes provided at nine locations on the peripheral edges of the base plate portion 331 and the cover plate portion 332, respectively, and the plate portions 331 and 332 are fastened together. Bolted to the cylinder block 6. By tightening the mounting bolt 348, the peripheral portions of the base plate portion 331 and the cover plate portion 332 are closely 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 fixed. The peripheral portions are closely fixed to each other, and the peripheral portion of the cooling water introduction port 328 of the cylinder block 6 and the peripheral portion of the pump discharge port 335 of the cooling water pump 21 are closely fixed to each other. In an arrangement of bolts 347,348 along the peripheral edge of the cooling water pump 21, one or two mounting bolts 348 are arranged between adjacent cover bolts 347,347.

Since the base plate portion 331 and the cover plate portion 332 are connected by the cover bolt 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 bolt 348. Installation work becomes easy.

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

The peripheral portions of the base plate portion 331 and the cover plate portion 332 are brought into close contact with each other to form a cooling water passage 336 in the pump connecting the pump suction port 334 and the pump discharge port 335. An annular seal member surrounding the pump suction port 334, the pump discharge port 335, and the cooling water passage 336 in the pump is arranged in the close 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 to one end portion. The 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 is opened in the inlet pipe mounting seat 320 projecting from the left side surface. Inside the cylinder block 6, a substantially L-shaped cooling water passage 338 (cooling water passage) is formed in the block, which connects the cooling water passage inlet 329 opened on the left side surface and the cooling water passage outlet 327 opened on the rear side surface. Has been done.

A pair of bolt holes are formed in the inlet pipe mounting seat 320 with the cooling water passage inlet 329 interposed therebetween, 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. Bolted as possible. A pipe connected to the cooling water outlet of the radiator is connected to the cooling water inlet pipe 22. The cooling water from the radiator is taken into the engine 1 from the cooling water inlet pipe 22, and is introduced into the cylinder block 6 from the cooling water introduction port 328 via the cooling water passage 338 in the block and the cooling water pump 21.

In the engine 1 of this embodiment, since the cooling water inlet pipe 22 having the cooling water inlet 339 is detachably attached to the cooling water passage inlet 329 connected to the pump suction port 334 of the cooling water pump 21, the cooling water inlet pipe 22 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 significant design change or an increase in manufacturing cost.

Further, a cooling water passage outlet 327 for supplying the cooling water from the radiator to the cooling water pump 21 and a cooling water introduction port 328 for introducing the cooling water from the cooling water pump 21 into the cylinder block 6 are located on the left and right sides of the cylinder block 6. They are sorted and arranged. Further, the cooling water passage 336 in the pump connecting the cooling water passage outlet 327 and the cooling water introduction port 328 is arranged from the portion closer to the left side to the portion closer to the right side of the cylinder block 6. With such a configuration, the cooling water passing through the cooling water passage 336 in the pump 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 introduction port 328. Will be done. Therefore, since the cooling water can be cooled in the cooling water pump 21 before being introduced into the cylinder block 6 from the cooling water introduction port 328, 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 changes can be made without departing from the spirit of the present invention.

1 Engine 2 Cylinder head 3 Intake manifold 4 Exhaust manifold 5 Crank shaft 6 Cylinder block 7 Fly wheel housing 8 Fly wheel 9 Cooling fan 51 High pressure supercharger 52 Low pressure supercharger 53 High pressure turbine 54 High pressure turbine 55 High pressure turbine 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 port 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 Westgate 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 Connecting member 79 Connecting joint 80 Connecting joint

Claims (5)

An engine device including an exhaust manifold and an intake manifold arranged on a cylinder head, and a supercharger that compresses fresh air flowing into the intake manifold by the fluid energy of exhaust gas discharged from the exhaust manifold.
The turbocharger is composed of a high-pressure turbocharger connected to the exhaust manifold and a two-stage turbocharger composed of a low-pressure turbocharger connected to the high-pressure turbocharger.
The high-pressure turbocharger is arranged at a position facing the exhaust manifold from the side opposite to the cylinder head.
In the low-pressure compressor of the low-pressure turbocharger, the fresh air inlet is provided on the cylinder head side of the fresh air outlet in a plan view.
An engine device characterized in that the center of the low-pressure turbocharger is arranged closer to the cylinder head side in a plan view than the center of the high-pressure turbocharger . The engine device according to claim 1, wherein the fresh air outlet is provided so as to project from the left and right sides of the low-pressure compressor. The engine device according to claim 2, wherein the low-pressure compressor has the fresh air inlet and the fresh air outlet facing one side in the front-rear direction. The engine device according to claim 3, wherein the fresh air inlet of the high-pressure compressor of the high-pressure turbocharger faces one side in the front-rear direction. One of claims 1 to 4, wherein the high-pressure turbocharger is arranged on the left and right sides of the exhaust manifold, and the low-pressure turbocharger is arranged above the exhaust manifold. The engine device described in.

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