JP7482813B2 - Engine equipment - Google Patents

Description

This invention relates to an engine device equipped with an exhaust pressure sensor that detects the exhaust gas pressure in the exhaust manifold.

Conventionally, engine devices equipped with an exhaust pressure sensor that detects the exhaust gas pressure in the exhaust gas path are known (see, for example, Patent Documents 1 and 2). Because the exhaust pressure sensor is sensitive to heat, the exhaust gas path and the exhaust pressure sensor are connected via a pipe for detecting exhaust pressure so that the heat of the exhaust gas and the heat of the components that form the exhaust gas path are not transmitted to the exhaust pressure sensor beyond an acceptable range.

JP 2015-117585 A Patent Publication No. 2015-183549

The technical objective of this invention is to prevent failure or malfunction of the exhaust pressure sensor.

The engine device of the present invention is an engine device that includes an exhaust manifold provided on the exhaust side of the cylinder head and an exhaust pressure sensor that detects exhaust gas pressure, and the exhaust pressure sensor is attached to the cylinder head.

In the engine device of the present invention, for example, the exhaust pressure sensor may be provided in an exhaust pressure detection path provided in the cylinder head.

In the engine device of the present invention, for example, an exhaust pressure detection pipe may be provided that connects the exhaust pressure detection path and the exhaust manifold. Also, for example, a cooling water path may be provided in the cylinder head near the exhaust pressure detection path.

The engine device of the present invention can prevent the exhaust pressure sensor from failing or malfunctioning.

FIG. 1 is a schematic front view of an embodiment of an engine apparatus. FIG. FIG. 2 is a schematic left side view of the embodiment. FIG. FIG. FIG. 2 is an enlarged schematic left side view showing the periphery of a two-stage turbocharger. FIG. 2 is an enlarged schematic front view showing the two-stage turbocharger and its periphery. FIG. 2 is an enlarged schematic rear view showing the two-stage turbocharger and its periphery. FIG. 2 is a schematic plan view showing an enlarged view of the periphery of a low-pressure stage turbocharger with a part of the cylinder head cover cut away. FIG. 2 is a schematic perspective view for explaining a mounting structure of the low-pressure stage turbocharger. 2 is an enlarged schematic front view showing the periphery of a support base that supports the exhaust gas purification device; FIG. FIG. 2 is a schematic left side view showing an enlarged view of the support base and its periphery. FIG. 2 is a schematic right side view showing an enlarged view of the support base and its periphery. FIG. 2 is an enlarged schematic plan view showing the periphery of the support base. FIG. 4 is a schematic exploded perspective view for explaining a mounting structure of the support base and the exhaust gas purification device. 15 is a schematic left side view showing the support base and the exhaust gas purification device along the AA cross section in FIG. 14. FIG. 2 is an enlarged schematic front view showing the periphery of a cylinder head. FIG. 2 is an enlarged schematic plan view showing the periphery of a front portion of the cylinder head. FIG. 2 is a schematic left side view showing an enlarged view of the front periphery of the cylinder head. FIG. 2 is a schematic perspective view showing a front portion of the cylinder head and an EGR cooler with a portion cut away. FIG. 2 is a schematic cross-sectional plan view showing the configuration of an exhaust flow path and an intake flow path in a cylinder head. FIG. 2 is a schematic front view showing the arrangement of wire harnesses around a front portion of a cylinder head. FIG. 2 is a schematic plan view showing the arrangement of wire harnesses around a front portion of a cylinder head.

Below, an embodiment of the present invention will be described with reference to the drawings. First, the overall structure of engine 1, an example of an engine device, will be described with reference to Figs. 1 to 5. In this embodiment, engine 1 is a diesel engine. In the following description of engine 1, both sides parallel to crankshaft 5 (both sides sandwiching crankshaft 5) will be referred to as the left and right, the side where flywheel housing 7 is installed will be referred to as the front side, and the side where cooling fan 9 is installed will be referred to as the rear side, and for convenience, these will be used as the basis for the positional relationships of the four sides and the top and bottom of engine 1.

As shown in Figures 1 to 5, the intake manifold 3 is disposed on one side parallel to the crankshaft 5 of the engine 1, and the exhaust manifold 4 is disposed on the other side. In this embodiment, the intake manifold 3 is molded integrally with the cylinder head 2 on the right side of the cylinder head 2. The 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 that houses the crankshaft 5 and pistons (not shown).

The front and rear ends of the crankshaft 5 protrude from both the front and rear side surfaces of the cylinder block 6. A flywheel housing 7 is fixed to one side of the engine 1 that intersects with the crankshaft 5 (the front side surface of the cylinder block 6 in this embodiment). A flywheel 8 is disposed within the flywheel housing 7. The flywheel 8 is fixed to the front end side of the crankshaft 5 and is configured to rotate integrally with the crankshaft 5. The engine 1 is configured to extract power from the flywheel 8 to a working part of a work machine (e.g., a hydraulic excavator, a forklift, etc.). A cooling fan 9 is provided on the other side of the engine 1 that intersects with the crankshaft 5 (the rear side surface of the cylinder block 6 in this embodiment). The rotational force is transmitted from the rear end side of the crankshaft 5 to the cooling fan 9 via a belt 10.

An oil pan 11 is disposed on the underside of the cylinder block 6. Lubricating oil is stored in the oil pan 11. The lubricating oil in the oil pan 11 is sucked up by a lubricating oil pump (not shown) disposed on the right side of the cylinder block 6, which is the connecting portion between the cylinder block 6 and the flywheel housing 7, and is supplied to each lubricated part of the engine 1 via an oil cooler 13 and an oil filter 14 disposed on the right side of the cylinder block 6. The lubricating oil supplied to each lubricated part is then returned to the oil pan 11. The lubricating oil pump is configured to be driven by the rotation of the crankshaft 5.

As shown in FIG. 4, a fuel supply pump 15 for supplying fuel is attached to the right side of the engine 1 at the connection portion with the flywheel housing 7 of the cylinder block 6. The fuel supply pump 15 is disposed below the EGR device 24. A common rail 16 is disposed between the intake manifold 3 of the cylinder head 2 and the fuel supply pump 15. The common rail 16 is fixed to the upper front portion of the right side of the cylinder block 6. An injector (not shown) for each of the four cylinders, which has an electromagnetic opening/closing type fuel injection valve, is provided on the upper surface of the cylinder head 2, which is covered by the cylinder head cover 18.

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

As shown in Figures 2 and 5, a blow-by gas reduction device 19 that takes in blow-by gas that leaks from the combustion chamber of the engine 1 to the upper side of the cylinder head 2 is provided on the upper surface of a cylinder head cover 18 that covers the intake valve and exhaust valve (not shown) provided on the upper surface of the cylinder head 2. The blow-by gas outlet of the blow-by gas reduction device 19 is connected to the intake part of the two-stage turbocharger 30 via a reduction hose 68. The blow-by gas from which the lubricating oil components have been removed in the blow-by gas reduction device 19 is returned to the intake manifold 3 via the two-stage turbocharger 30, etc.

As shown in FIG. 3, on the left side of the engine 1, an engine starter 20 is attached to the flywheel housing 7. The engine starter 20 is disposed below the exhaust manifold 4. The engine starter 20 is attached to the left side of the rear side of the flywheel housing 7, below the connection between the cylinder block 6 and the flywheel housing 7.

As shown in FIG. 2, a cooling water pump 21 for cooling water lubrication is disposed on the left side of the rear side of the cylinder block 6. An alternator 12 is provided to the left of the cooling water pump 21 as a generator that generates electricity using the power of the engine 1. Rotational power is transmitted from the front end of the crankshaft 5 via a belt 10 to the cooling fan 9, the alternator 12, and the cooling water pump 21. 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 then supplied to the cylinder head 2 and the cylinder block 6 to cool the engine 1.

As shown in FIG. 3, the cooling water pump 21 is disposed at a lower height than the exhaust manifold 4, and the cooling water inlet pipe 22, which is connected to the cooling water outlet of the radiator, is fixed to the left side surface of the cylinder block 6 at approximately the same height as the cooling water pump 21. On the other hand, the cooling water outlet pipe 23, which is connected to the cooling water inlet of the radiator, is fixed to the right rear portion of the upper surface of the cylinder head 2, as shown in FIG. 2 and FIG. 5. The cylinder head 2 has a cooling water drain 35 at its right rear corner, and the cooling water outlet pipe 23 is installed on the upper surface of the cooling water drain 35.

As shown in Figures 4 and 5, the EGR device 24 is disposed on the right side of the cylinder head 2. The EGR device 24 has a collector 25 as a relay pipe that mixes the recirculated exhaust gas (EGR gas from the exhaust manifold 4) of the engine 1 with fresh air (external air from the air cleaner) and supplies it to the intake manifold 3, an intake throttle member 26 that connects the collector 25 to the air cleaner, a recirculated exhaust gas pipe 28 that is part of the return pipe that connects to the exhaust manifold 4 via an EGR cooler 27, and an EGR valve member 29 that connects the collector 25 to the recirculated exhaust gas pipe 28.

In this embodiment, the collector 25 of the EGR device 24 is connected to the right side of the intake manifold 3, which is molded integrally with the cylinder head 2 and forms the right side of the cylinder head 2. That is, the outlet opening of the collector 25 is connected to the inlet opening of the intake manifold 3 provided on the right side of the cylinder head 2. Also, the EGR gas inlet of the recirculated exhaust gas piping 28 is connected to the EGR gas outlet of the EGR gas passage provided in the cylinder head 2 at a forward portion of the right side of the cylinder head 2. The collector 25 is attached to the intake manifold 3 and the recirculated exhaust gas piping 28 is attached to the cylinder head 2, whereby the EGR device 24 is fixed to the cylinder head 2.

In the EGR device 24, the intake manifold 3 and the intake throttle member 26 for introducing fresh air are connected through the collector 25. The collector 25 is connected to an EGR valve member 29 that is connected to the outlet side of the recirculated exhaust gas pipe 28. The collector 25 is formed in a roughly cylindrical shape that is longitudinal from front to rear. The intake throttle member 26 is bolted to the intake side (front side in the longitudinal direction) of the collector 25. The intake and exhaust side of the collector 25 is bolted to the inlet side of the intake manifold 3. The EGR valve member 29 adjusts the opening of the EGR valve inside it to adjust the amount of EGR gas supplied to the collector 25.

Fresh air is supplied to the collector 25, and EGR gas (a portion of the exhaust gas discharged from the exhaust manifold 4) is supplied to the collector 25 from the exhaust manifold 4 via the EGR valve member 29. After the fresh air and the EGR gas from the exhaust manifold 4 are mixed in the collector 25, the mixed gas in the collector 25 is supplied to the intake manifold 3. In other words, by returning a portion of the exhaust gas discharged from the engine 1 to the exhaust manifold 4 from the intake manifold 3 to the engine 1, the maximum combustion temperature during high load operation is lowered, and the amount of NOx (nitrogen oxides) emitted from the engine 1 is reduced.

As shown in Figures 1 and 3 to 5, the EGR cooler 27 is fixed to the front side of the cylinder head 2. Cooling water and EGR gas flowing through the cylinder head 2 flow in and out of the EGR cooler 27, and the EGR gas is cooled in the EGR cooler 27. A pair of left and right EGR cooler connecting parts 33, 34 that connect the EGR cooler 27 protrude from the front side of the cylinder head 2. The EGR cooler 27 is connected to the front sides of the EGR cooler connecting parts 33, 34. In other words, the EGR cooler 27 is disposed above the flywheel housing 7 and in front of the cylinder head 2, with the rear side of the EGR cooler 27 and the front side of the cylinder head 2 spaced apart.

As shown in Figures 1 to 3 and 5, a two-stage turbocharger 30 is disposed on the left side of the cylinder head 2. The two-stage turbocharger 30 includes a high-pressure stage turbocharger 51 and a low-pressure stage turbocharger 52. The high-pressure stage turbocharger 51 includes a high-pressure stage turbine case 53 incorporating a turbine wheel (not shown) and a high-pressure stage compressor case 54 incorporating a blower wheel (not shown). The low-pressure stage turbocharger 52 includes a low-pressure stage turbine case 55 incorporating a turbine wheel (not shown) and a low-pressure stage compressor case 56 incorporating a blower wheel (not shown).

In the exhaust path of the two-stage turbocharger 30, the high-pressure stage turbine case 53 is connected to the exhaust manifold 4, the low-pressure stage turbine case 55 is connected to the high-pressure stage turbine case 53 via a high-pressure exhaust gas pipe 59, and the low-pressure stage turbine case 55 is connected to an exhaust connecting pipe 119. The high-pressure exhaust gas pipe 59 is formed of a flexible pipe. In this embodiment, a portion of the high-pressure exhaust gas pipe 59 is formed in a bellows shape.

A tail pipe (not shown) is connected to the exhaust manifold 119 via the exhaust gas purification device 100. The exhaust gas discharged from each cylinder of the engine 1 to the exhaust manifold 4 passes through the two-stage turbocharger 30 and the exhaust gas purification device 100, etc., and is released to the outside from the tail pipe.

In the intake path of the two-stage turbocharger 30, the low-pressure compressor case 56 is connected to the air cleaner via an intake pipe 62, the high-pressure compressor case 54 is connected to the low-pressure compressor case 56 via a low-pressure fresh air passage pipe 65, and the intake throttle member 26 of the EGR device 24 is connected to the high-pressure compressor case 54 via an intercooler (not shown). Fresh air (outside air) sucked into the air cleaner is cleaned and purified by the air cleaner, then sent to the intake manifold 3 via the two-stage turbocharger 30, the intercooler, the intake throttle member 26, the collector 25, etc., and is then supplied to each cylinder of the engine 1.

The exhaust gas purification device 100 is for collecting particulate matter (PM) and the like in exhaust gas. As shown in Figs. 1 to 5, the exhaust gas purification device 100 has a generally cylindrical shape that extends long in the left-right direction intersecting with the crankshaft 5 in a plan view. In this embodiment, the exhaust gas purification device 100 is disposed above the front side surface of the cylinder head 2. The exhaust gas purification device 100 is supported at the front of the cylinder head 2 via a left support bracket 117, a right support bracket 118, and a support stand 121.

The exhaust gas purification device 100 has an exhaust gas intake side and an exhaust gas discharge side on both the left and right sides (one longitudinal end side and the other longitudinal end side). The exhaust gas inlet pipe 116 on the exhaust gas intake side of the exhaust gas purification device 100 is connected to the exhaust outlet of the low-pressure stage turbine case 55 of the two-stage turbocharger 30 via an exhaust connection member 120 having an exhaust gas passage that is approximately L-shaped when viewed from the side and a straight exhaust connection pipe 119. The exhaust connection member 120 is fixed to the left side surface of the support base 121. The exhaust gas discharge side of the exhaust gas purification device 100 is connected to the exhaust gas intake side of the tail pipe (not shown).

The exhaust gas purification device 100 has a structure in which a diesel oxidation catalyst 102 made of, for example, platinum and a soot filter 103 having a honeycomb structure are arranged in series and housed inside. In the above configuration, nitrogen dioxide (NO2) generated by the oxidation action of the diesel oxidation catalyst 102 is taken into the soot filter 103. Particulate matter contained in the exhaust gas of the engine 1 is collected by the soot filter 103 and is continuously oxidized and removed by the nitrogen dioxide. Therefore, in addition to removing particulate matter (PM) from the exhaust gas of the engine 1, the carbon monoxide (CO) and hydrocarbon (HC) content in the exhaust gas of the engine 1 is reduced.

The exhaust gas purification device 100 comprises an upstream case 105 having an exhaust gas inlet pipe 116 on its outer periphery, an intermediate case 106 connected to the upstream case 105, and a downstream case 107 connected to the intermediate case 106. The upstream case 105 and the intermediate case 106 are connected in series to form a gas purification housing 104 made of a heat-resistant metal material. The gas purification housing 104 contains a diesel oxidation catalyst 102 and a soot filter 103 via a cylindrical inner case (not shown). The downstream case 107 also contains an inner case (not shown) with many sound absorbing holes, and a ceramic fiber sound absorbing material is filled between the inner case and the downstream case to form a muffler.

When the exhaust gas passes through the diesel oxidation catalyst 102 and the soot filter 103, if the exhaust gas temperature exceeds the regeneration temperature (e.g., about 300°C), the diesel oxidation catalyst 102 oxidizes the nitric oxide in the exhaust gas to unstable nitrogen dioxide. The particulate matter accumulated on the soot filter 103 is then oxidized and removed by the oxygen released when the nitrogen dioxide returns to nitric oxide, thereby restoring the particulate matter collection ability of the soot filter 103 and regenerating the soot filter 103.

Next, the configuration and mounting structure of the two-stage turbocharger 30 will be described with reference to Figures 6 to 10. The two-stage turbocharger 30 compresses fresh air flowing into the intake manifold 3 of the cylinder head 2 using the fluid energy of the exhaust gas discharged from the exhaust manifold 4. The two-stage turbocharger 30 is composed of a high-pressure stage turbocharger 51 connected to the exhaust manifold 4, and a low-pressure stage turbocharger 52 connected to the high-pressure stage turbocharger 51.

As shown in Figures 7 and 8, the high-pressure stage turbocharger 51 is disposed on the left side of the exhaust manifold 4. The low-pressure stage turbocharger 52 is disposed above the exhaust manifold 4. That is, the small-capacity high-pressure stage turbocharger 51 is disposed facing the left side of the exhaust manifold 4, while the large-capacity low-pressure stage turbocharger 52 is disposed facing the left side of the cylinder head 2 and the cylinder head cover 18. Therefore, not only can the exhaust manifold 4 and the two-stage turbocharger 30 be compactly disposed within a substantially rectangular frame in front and rear views in the space to the left of the cylinder head 2, but the top position of the two-stage turbocharger 30 can be lower than the top position of the engine 1. This contributes to the miniaturization of the engine 1.

As shown in Figures 3 and 6, when the engine 1 is viewed from the left side, the low-pressure stage turbocharger 52 is disposed on the left side of the cylinder head 2 and in front of the high-pressure stage turbocharger 51. This allows for a larger space to be provided below the low-pressure stage turbocharger 52 and around the front left side of the cylinder block 6 for arranging other application parts. For example, an external auxiliary device such as a hydraulic pump that is operated by the rotational force of the crankshaft 5 can be disposed between the low-pressure stage turbocharger 52 and the engine starter 20.

As shown in Figures 6 to 8, the high-pressure stage turbocharger 51 includes a high-pressure stage turbine case 53, a high-pressure stage compressor case 54 arranged on the rear side of the high-pressure stage turbine case 53, and a high-pressure stage center housing 72 connecting both cases 53, 54. The high-pressure stage turbine case 53 includes a high-pressure stage exhaust inlet 57 communicating with the exhaust manifold exhaust outlet 49 of the exhaust manifold 4, and a high-pressure stage exhaust outlet 58 communicating with the upstream end of the high-pressure exhaust gas piping 59. The high-pressure stage compressor case 54 includes a high-pressure stage fresh air inlet 66 communicating with the downstream end of the low-pressure fresh air passage pipe 65, and a high-pressure stage fresh air supply port 67 connected to an intercooler (not shown). Note that the upstream end of the pipe means the upstream end of the gas flow, and the downstream end means the downstream end of the gas flow.

On the other hand, the low-pressure stage turbocharger 52 includes a low-pressure stage turbine case 55, a low-pressure stage compressor case 56 arranged on the rear side of the low-pressure stage turbine case 55, and a low-pressure stage center housing 75 connecting both cases 55, 56. The low-pressure stage turbine case 55 includes a low-pressure stage exhaust inlet 60 communicating with the downstream end of the high-pressure exhaust gas piping 59, and a low-pressure stage exhaust outlet 61 communicating with the upstream end of the exhaust connecting pipe 119. The low-pressure stage compressor case 56 includes a low-pressure stage fresh air inlet 63 communicating with the downstream end of the intake pipe 62, and a low-pressure stage fresh air supply port 64 communicating with the upstream end of the low-pressure fresh air passage pipe 65.

The exhaust manifold 4 has an exhaust manifold exhaust outlet 49 that discharges exhaust gas and opens to the left. The high-pressure stage turbine case 53 has a high-pressure stage exhaust inlet 57 that opens toward the exhaust manifold 4, while a high-pressure stage exhaust outlet 58 that opens forward. The low-pressure stage turbine case 55 has a low-pressure stage exhaust inlet 60 that opens downward, while a low-pressure stage exhaust outlet 61 that opens forward.

As shown in Figures 6 to 8, in the two-stage turbocharger 30, the high-pressure stage compressor case 54 has a high-pressure stage fresh air inlet 66 opening toward the rear, while the high-pressure stage fresh air supply port 67 opening downward. Also, the low-pressure stage compressor case 56 has a low-pressure stage fresh air inlet 63 opening toward the rear, while the low-pressure stage fresh air supply port 64 protrudes from the left side and faces rearward. The downstream end of a U-shaped low-pressure fresh air passage pipe 65 is connected to the high-pressure stage fresh air inlet 66, while the low-pressure stage fresh air supply port 64 is connected to the upstream end of the low-pressure fresh air passage pipe 65.

As shown in Figures 6 to 8, the exhaust manifold exhaust outlet 49 of the exhaust manifold 4 and the high-pressure stage exhaust inlet 57 of the high-pressure stage turbine case 53 are bolted together at the flange. This allows the high-pressure stage turbocharger 51 to be fixed to the robust exhaust manifold 4. The high-pressure stage exhaust outlet 58 of the high-pressure stage turbine case 53 is bolted together at the flange to the downstream end (rear end) of the approximately L-shaped high-pressure exhaust gas pipe 59, while the low-pressure stage exhaust inlet 60 of the low-pressure stage turbine case 55 is bolted together at the flange to the upstream end (upper end) of the high-pressure exhaust gas pipe 59. The approximately L-shaped high-pressure exhaust gas pipe 59 is made of flexible pipe, and in this embodiment, the bellows tube section 59a is provided at the portion extending in the front-rear direction.

9 and 10, the low-pressure stage turbocharger 52 is fixed to the left side surface (exhaust side surface) of the cylinder head 2. In this embodiment, a low-pressure stage turbocharger mounting portion 131 is provided in a central front portion of the left side surface of the cylinder head 2 (see also Figs. 12, 16, and 19). The low-pressure stage turbocharger mounting portion 131 is provided above the exhaust manifold 4 and in a position facing the low-pressure stage turbine case 55. The low-pressure stage turbocharger 52 is attached to the low-pressure stage turbocharger mounting portion 131 via a substantially L-shaped mounting bracket 132. The mounting bracket 132 has a turbocharger side flat portion 132a arranged in the left-right direction and a head side flat portion 132b protruding forward from the right end of the turbocharger side flat portion 132a.

The turbocharger side flat surface 132b of the mounting bracket 132 is fixed to the right edge of the front side of the low-pressure stage compressor case 56 by bolts 133. The head side flat surface 132a of the mounting bracket 132 is fixed to the low-pressure stage turbocharger mounting portion 131 by a pair of front and rear bolts 133. In this way, the low-pressure stage turbocharger 52 is fixed to the sturdy cylinder head 2.

In this embodiment, the low-pressure stage turbocharger 52 is fixed to the left side (exhaust side) of the cylinder head 2, and the high-pressure stage turbocharger 51 is fixed to the exhaust manifold 4, so that the high-pressure stage turbocharger 51 and the low-pressure stage turbocharger 52 constituting the two-stage turbocharger 30 can be firmly fixed to the robust cylinder head 2 and exhaust manifold 4. In addition, the low-pressure stage turbocharger 52 is connected to a support base 121 fixed to the front of the cylinder head 2 via an exhaust connecting pipe 119 and an exhaust connecting member 120, so that the low-pressure stage turbocharger 52 can be reliably fixed to the engine 1, and thus the two-stage turbocharger 30 can be reliably fixed to the engine 1.

In addition, the high-pressure stage exhaust outlet 58 of the high-pressure stage turbocharger 51 and the low-pressure stage exhaust inlet 60 of the low-pressure stage turbocharger 52 are connected via a flexible high-pressure exhaust gas piping 59, which reduces the risk of low-cycle fatigue failure of the high-pressure exhaust gas piping 59 due to thermal expansion. Furthermore, the stress applied to the two-stage turbocharger 30 due to thermal expansion of the high-pressure exhaust gas piping 59 can be reduced. This reduces the stress applied to the connection between the high-pressure stage turbocharger 51 and the exhaust manifold 4 and the connection between the low-pressure stage turbocharger 52 and the cylinder head 2, preventing poor connection at these connections and damage to the connection members.

As shown in Figures 9 and 10, the cylinder head 2 has a rib 135 extending from the low-pressure stage turbocharger mounting portion 131 toward the right side (intake side) of the cylinder head 2. The rib 135 protrudes upward from the cylinder head bottom surface 136. This improves the rigidity of the area around the low-pressure stage turbocharger mounting portion 131 in the cylinder head 2, and prevents deformation of the cylinder head 2 caused by mounting the low-pressure stage turbocharger 52 to the cylinder head 2. In addition, a valve arm mechanism mounting seat 137 extending in the left-right direction is protruded upward from the cylinder head bottom surface 136, continuing from the right end of the rib 135. This improves the rigidity of the rib 135, and therefore the rigidity of the area around the low-pressure stage turbocharger mounting portion 131.

In this embodiment, the engine 1 is an OHV type, and the space surrounded by the cylinder head 2 and the cylinder head cover 18 constitutes the valve arm chamber. As shown in FIG. 9, the injector 138 and the valve mechanism are housed in the valve arm chamber. A plurality of valve arm mechanism mounting seats 137 are arranged at equal intervals in the front-rear direction, and a valve arm shaft support portion 139 that supports a valve arm shaft (not shown) is arranged on the valve arm mechanism mounting seats 137, and a plurality of valve arms 140 are supported on the valve arm shaft so that they can swing freely. Each valve arm 189 swings around the valve arm shaft, opening and closing the intake valve and exhaust valve (not shown) of each cylinder.

3, 5 and 6, the low-pressure stage turbocharger 52 is disposed near the front side (one side) of the cylinder head 2 when viewed from the left side, while the low-pressure stage exhaust outlet 61 of the low-pressure stage turbine case 55 is provided toward the front side of the cylinder head 2. In addition, the exhaust gas inlet pipe 116 constituting the exhaust inlet of the exhaust gas purification device 100 is disposed near the corner where the front side and the right side (exhaust side) of the cylinder head 2 intersect. Therefore, the exhaust connection pipe 119 and the exhaust connection member 120 as piping connecting the low-pressure stage exhaust outlet 61 of the low-pressure stage turbocharger 52 and the exhaust gas inlet pipe 116 of the exhaust gas purification device 100 can be made short and simple. As a result, the exhaust gas supplied to the exhaust gas purification device 100 can be maintained at a high temperature, and the deterioration of the regeneration ability of the exhaust gas purification device 1 can be prevented.

In the present invention, as long as the exhaust inlet of the exhaust gas purification device 100 is arranged near the corner where the front side (one side) and the right side (exhaust side) of the cylinder head 2 intersect, the same effect as this embodiment can be obtained regardless of the mounting position or arrangement direction of the exhaust gas purification device 100. For example, the exhaust gas purification device 100 may be arranged horizontally in front of the cylinder head 2 and above the flywheel housing 7 (see, for example, JP 2011-012598 A), or may be arranged horizontally in front of the cylinder head 2 (direction along the crankshaft 5) (see, for example, JP 2016-079870 A).

3, 5 and 6, 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 mounted and fixed on the upper surface of the cylinder head cover 18 that covers the upper surface of the cylinder head 2. Above the cylinder head 2, the blow-by gas outlet 70 of the blow-by gas reduction device 19 is disposed toward the left side at a position near the rear side (the other side) of the cylinder head 2. In addition, the low-pressure stage fresh air inlet 63 of the low-pressure stage compressor case 56 of the low-pressure stage turbocharger 52 opens toward the rear. An intake pipe 62 extending in the front-rear direction is connected to the low-pressure stage fresh air inlet 63. This allows the intake pipe 62 to be disposed near the blow-by gas outlet 70, and the reduction hose 68 connecting the blow-by gas outlet 70 and the intake pipe 62 to be shortened, thereby preventing freezing inside the reduction hose 68 in a low-temperature environment.

As shown in FIG. 6, the low-pressure stage compressor case 56 and the high-pressure stage compressor case 54 have the low-pressure stage fresh air inlet 63, the low-pressure stage fresh air supply port 64, and the high-pressure stage fresh air inlet 66 open in the same direction (rearward). This makes it easy to connect the air intake pipe 62 that communicates with the air cleaner to the low-pressure stage fresh air inlet 63, and also makes it easy to connect the low-pressure fresh air passage pipe 65 to the low-pressure stage fresh air supply port 64 and the high-pressure stage fresh air inlet 66, improving assembly workability.

The low-pressure fresh air passage pipe 65 is composed of a generally U-shaped metal pipe 65a, one end of which is bolted to the high-pressure stage fresh air inlet 66 by a flange connection, and a resin pipe 65b that connects the other end of the metal pipe 65a to the low-pressure stage fresh air supply port 64 of the low-pressure stage compressor case 56. As a result, the low-pressure fresh air passage pipe 65 is fixed with high rigidity to the high-pressure stage compressor case 54 by the metal pipe 65a, while the resin pipe 65b allows the low-pressure stage compressor case 56 and the metal pipe 65a to communicate with each other while mitigating assembly errors due to the assembly error.

The low-pressure fresh air supply port 64 of the low-pressure compressor case 56 extends diagonally upward to the left from the lower left part of the outer circumferential surface of the low-pressure compressor case 56 and is further curved toward the rear, so that the curvature of the bent portion of the low-pressure fresh air passage pipe 65 (metal pipe 65a) can be increased. This suppresses the generation of turbulence in the low-pressure fresh air passage pipe 65, and the compressed air discharged from the low-pressure compressor case 56 is smoothly supplied to the high-pressure compressor case 54.

As shown in FIG. 8, the high-pressure stage turbocharger 51 has a fresh air supply port 64 extending downward from the right side of the lower outer peripheral surface of the high-pressure stage compressor case 54. The high-pressure stage compressor case 54 is connected to a high-pressure fresh air passage pipe 71 that is connected to the intercooler, and supplies compressed air to the intercooler via the high-pressure fresh air passage pipe 71. In addition, a cooling water inlet pipe 22 that opens toward the left side is provided below the high-pressure stage compressor case 54. A cooling water pipe 150 that leads to a radiator is connected to the cooling water inlet pipe 22. This allows the high-pressure fresh air passage pipe 71 and the cooling water pipe 150 to be centralized, which not only simplifies the piping structure on the main unit side on which the engine 1 is mounted, but also makes it easier to perform assembly and maintenance work.

As shown in Figures 2, 4 and 5, the engine 1 has the cooling water outlet pipe 23, the air intake pipe 62 and the intake throttle member 26 arranged at its rear (the cooling fan 9 side). Therefore, when a radiator, air cleaner and intercooler that uses the cooling air from the cooling fan 9 are arranged behind the cooling fan 9 on the main machine on which the engine 1 is mounted, not only can the cooling water piping that connects to the radiator and the fresh air piping that communicates with the air cleaner and intercooler be shortened, but the piping connection work can be done all at once. This not only makes the assembly and maintenance work on the main machine easier, but also allows the various parts that are connected to the engine 1 to be arranged efficiently on the main machine.

As shown in Figures 6 to 8, in the high-pressure stage turbocharger 51, a high-pressure lubricating oil supply pipe 73 and a high-pressure lubricating oil return pipe 74 are connected to the upper and lower parts of the outer peripheral surface of the high-pressure stage center housing 72, which is the connecting part between the high-pressure stage turbine case 53 and the high-pressure stage compressor case 54. In the low-pressure stage turbocharger 52, a low-pressure lubricating oil supply pipe 76 and a low-pressure lubricating oil return pipe 77 are connected to the upper and lower parts of the outer peripheral surface of the low-pressure stage center housing 75, which is the connecting part between the low-pressure stage turbine case 55 and the low-pressure stage compressor case 56.

The lower end of the high-pressure lubricating oil supply pipe 73 is connected to a connecting member 78a provided in the center of the left side surface of the cylinder block 6, while the upper end is connected to the upper part of the high-pressure stage center housing 72 of the high-pressure stage turbocharger 51. A connecting joint 78b is provided at the upper part of the high-pressure stage center housing 72 to communicate the upper end of the high-pressure lubricating oil supply pipe 73 with the lower end of the low-pressure lubricating oil supply pipe 76. The upper end of the low-pressure lubricating oil supply pipe 76 is connected to a connecting member 78c provided at the upper part of the low-pressure stage center housing 75 of the low-pressure stage turbocharger 52. As a result, the lubricating oil flowing through the oil passage in the cylinder block 6 is supplied to the high-pressure stage center housing 72 of the high-pressure stage turbocharger 51 through the high-pressure lubricating oil supply pipe 73, and is supplied to the low-pressure stage center housing 75 of the low-pressure stage turbocharger 52 through the high-pressure lubricating oil supply pipe 73 and the low-pressure lubricating oil supply pipe 76.

The high-pressure lubricating oil supply pipe 73 is led from the connecting member 78a on the left side of the cylinder block 6 in a rearward and upward diagonal direction, and is led to a position facing the left side of the cylinder head 2 through between the high-pressure stage compressor case 54 and the cylinder block 6. Furthermore, the high-pressure lubricating oil supply pipe 73 is led to the connecting joint 78b, passing through the right side of the high-pressure stage center housing 72 while bypassing the rear end of the exhaust manifold 4. The low-pressure lubricating oil supply pipe 76 has a substantially L-shape in side view, and is led from the connecting joint 78b to the connecting member 78c along the high-pressure stage turbocharger 51 and the high-pressure exhaust gas pipe 59. In this way, by shortening the lubricating oil supply pipes 73 and 76 and piping them so as to be surrounded by the two-stage turbocharger 30, which is a highly rigid part, lubricating oil can be efficiently supplied to the two-stage turbocharger 30, and at the same time, damage to the lubricating oil supply pipes 73 and 76 due to external forces can be prevented.

The high-pressure lubricating oil return pipe 74 has one end (lower end) connected to the tip surface of the connecting joint 80 installed in the center of the left side surface of the cylinder block 6 above the connecting member 78a. The other end (upper end) of the high-pressure lubricating oil return pipe 74 is connected to the lower part of the outer circumferential surface of the high-pressure stage center housing 72 of the high-pressure stage turbocharger 51. The low-pressure lubricating oil return pipe 77 has one end (lower end) connected to a connection part protruding obliquely upward and forward from the middle of the connecting joint 80. On the other hand, the other end (upper end) of the low-pressure lubricating oil return pipe 77 is connected to the lower part of the outer circumferential surface of the low-pressure stage center housing 75 of the low-pressure stage turbocharger 52. Therefore, the lubricating oil flowing through the high-pressure stage turbocharger 51 and the low-pressure stage turbocharger 52 is joined at the connecting joint 80 from the lower part of the center housings 72, 75 via the lubricating oil return pipes 74, 77, and returned to the oil passage in the cylinder block 6.

The high-pressure lubricating oil return pipe 74 is led from below the high-pressure stage turbine case 53, passing below the exhaust manifold exhaust outlet 49 of the exhaust manifold 4, to the connecting joint 80. The low-pressure working return pipe 77 is led to the connecting joint 80, passing between the high-pressure exhaust gas pipe 59 and the exhaust manifold 4. In this way, by shortening the length of the lubricating oil return pipes 74, 77 and piping them so that they are covered by the two-stage turbocharger 30, which is a highly rigid part, lubricating oil can be efficiently supplied to the two-stage turbocharger 30, while preventing damage to the lubricating oil return pipes 74, 77 due to external forces.

Next, the mounting structure of the exhaust gas purification device 100 will be described with reference to Figures 11 to 16. The exhaust gas purification device 100 is configured by connecting an upstream case 105, an intermediate case 106, and a downstream case 107 in series in that order, and is disposed horizontally above the front of the cylinder head 2.

The connecting portion between the upstream case 105 and the intermediate case 106 is connected by a pair of thick plate-shaped clamping flanges 108, 109 on both sides in the exhaust gas movement direction. That is, the clamping flanges 108, 109 clamp the joint flange provided on the downstream opening edge of the upstream case 105 and the joint flange provided on the upstream opening edge of the intermediate case 106, connecting the downstream side of the upstream case 105 and the upstream side of the intermediate case 106 to form the gas purification housing 104. At this time, the clamping flanges 108, 109 are bolted together to removably connect the upstream case 105 and the intermediate case 106.

The connecting portion between the intermediate case 106 and the downstream case 107 is connected by a pair of thick plate-shaped clamping flanges 110, 111, which are sandwiched from both sides in the exhaust gas movement direction. That is, the joining flange provided on the downstream opening edge of the intermediate case 106 and the joining flange provided on the upstream opening edge of the downstream case 107 are sandwiched between the clamping flanges 108, 109, so that the downstream side of the intermediate case 106 and the upstream side of the downstream case 107 are detachably connected.

An exhaust gas inlet pipe 116 is provided on the outer periphery of the exhaust inlet side of the upstream case 105, and the exhaust intake side of the exhaust gas inlet pipe 116 is connected to the low-pressure stage exhaust outlet 61 (see FIG. 6, etc.) of the two-stage turbocharger 30 via an exhaust connection member 120 and an exhaust connection pipe 119 as an exhaust relay path. The exhaust connection member 120 is configured to be approximately L-shaped in side view, with the exhaust intake side provided at the rear and connected to the exhaust connection pipe 119, and the exhaust exhaust side provided at the top and connected to the exhaust gas inlet pipe 116 of the exhaust gas purification device 100. As shown in FIGS. 11, 12, and 16, the exhaust connection member 120 is detachably attached to the front part of the left side of the support base 121 by a pair of upper and lower bolts 122, 122.

As shown in Figures 11 and 15, the exhaust gas purification device 100 is attached to the front of the cylinder head 2 via left and right support brackets 117, 118 and a support base 121. The exhaust gas purification device 100 has a left bracket fastening leg 112 welded to the lower outer circumferential surface of the upstream casing 105, and a right bracket fastening leg 113 formed on the lower part of the clamping flange 110.

The left and right support brackets 117, 118 are generally L-shaped with a horizontal portion and upright portions protruding upward from the left and right outer ends of the horizontal portion. The horizontal portion of the left support bracket 117 is fixed to the left side of the upper surface of the flat portion 121a of the support base 121 by a pair of front and rear bolts. The horizontal portion of the right support bracket 118 is fixed to the right edge of the upper surface of the flat portion 121a of the support base 121 by a pair of front and rear bolts. The left and right bracket fastening legs 112, 113 of the exhaust gas purification device 100 are attached to the left and right support brackets 117, 118 by a pair of front and rear bolts and nuts, respectively.

A notch 118a is formed on the upper surface of the upright portion of the right support bracket 118, into which the heads of the bolts fastening the lower portions of the clamping flanges 110, 111 can be temporarily placed. When assembling the exhaust gas purification device 100 to the engine 1, the heads of the bolts fastening the lower portions of the clamping flanges 110, 111 are aligned with the notch 118a of the right support bracket 118 with the left and right support brackets 117, 118 and the exhaust connecting member 120 attached to the support base 121. This allows the exhaust gas purification device 100 to be aligned with the engine device 1, and also makes it easier to tighten the bolts when assembling the exhaust gas purification device 100 to the engine 1, improving assembly workability.

As shown in Figures 11 to 16, the flat surface 121a of the support base 121 has a generally L-shape with the right side longer than the left side in a plan view. The flat surface 121a is disposed along the front and right side surfaces of the cylinder head 2 so as to cover the front part of the cylinder head 2 in a plan view. The exhaust gas purification device 100 is mounted on the flat surface 121a.

The support base 121 also has multiple legs 121b, 121c, 121d, and 121e that protrude downward from the flat portion 121a and are fixed to the cylinder head 2. The spaces between the legs 121b, 121c, 121d, and 121e are formed into an arch shape that is convex upward. The cylinder head 2 has an exhaust side mounting portion 123b at the front portion of the left side surface, a first central mounting portion 123c at the upper center portion of the front side surface, a second central mounting portion 123d at the right edge portion of the front side surface, and an intake side mounting portion 123e at the front end portion of the upper surface of the intake manifold 3 that is integrally molded with the right side surface.

The lower end of the exhaust side leg 121b is fixed to the exhaust side mounting part 123b with a pair of front and rear bolts. The lower end of the first central leg 121c is fixed to the first central mounting part 123c with one bolt. The lower part of the second central leg 121d is fixed to the second central mounting part 123d with a pair of upper and lower bolts. The intake side leg 121e has a pair of front and rear bolt insertion holes drilled in the vertical direction, and is attached to the intake side mounting part 123e with a pair of front and rear bolts inserted into the bolt insertion holes.

As shown in Figures 11, 13 to 15, and 21, the intake manifold 3 is integrally molded on the right side of the cylinder head 2. The intake side leg 121e is fixed to the intake side mounting portion 123e provided on the intake manifold 3, so that the intake side leg 121e can be placed on the robust intake manifold 3 and firmly fixed thereto. In addition, the pair of front and rear bolts for fixing the intake side leg 121e to the intake manifold 3 can be tightened and loosened from above the cylinder head 2. Therefore, for example, the installation and removal of the support base 121 can be performed with the EGR device 24 (see Figure 5, etc.) located on the right side of the cylinder head 2 attached to the intake manifold 3, improving the ease of assembly and maintenance of the engine 1.

As shown in Figures 11, 13, and 15, a pair of front and rear reinforcing ribs 124, 124 protrude from the right side and bottom surface of the intake manifold 3 below the intake side mounting portion 123e. The reinforcing ribs 124, 124 extend in the vertical direction, improving the strength of the intake manifold 3 around the intake side mounting portion 123e. This makes it possible to prevent deformation of the intake manifold 3 and the cylinder head 2 caused by the attachment of the support base 121 to the intake manifold 3.

As shown in Figures 11 to 16, the support base 121 has a planar portion 121a and legs 121b, 121c, 121d, and 121e that are integrally molded, while the legs 121b, 121c, 121d, and 121e are formed in an arch shape, so that the support base 121 can be made lighter while maintaining its rigidity. Furthermore, by making the support base 121 an integrally molded part, the number of parts can be reduced. Furthermore, by forming arch-shaped gaps between the legs 121b, 121c, 121d, and 121e, it is possible to prevent heat pools from forming around the legs 121b, 121c, 121d, and 121e. This makes it possible to prevent heat damage to electronic components mounted around the legs, such as the exhaust pressure sensor 151 described below, and insufficient cooling of cooling components such as the EGR cooler 27.

The support base 121 also includes an exhaust-side leg 121b fixed to the left side of the cylinder head 2, an intake-side leg 121e fixed to the right side of the cylinder head 2, and central legs 121c and 121d fixed to the front side of the cylinder head 2. Therefore, the support base 121 can be fixed to a total of three sides of the right side, left side, and front side of the cylinder head 2, improving the support rigidity of the exhaust gas purification device 100.

As shown in Figures 11, 13, and 15, the arch shape between the intake side leg 121e and the second central leg 121d, the arch shape between the central legs 121c and 121d, and the arch shape between the exhaust side leg 121b and the first central leg 121c have different heights and sizes (widths). In addition, the exhaust side leg 121b and the intake side leg 121e have different lengths in the up-down direction. By appropriately designing these arch shapes and leg lengths, it becomes possible for the support base 121 to cancel out vibrations on the intake side and exhaust side, thereby reducing vibrations of the exhaust gas purification device 100.

11 and 16, the flat portion 121a and the legs 121b, 121c, 121d, and 121e of the support base 121 are spaced apart from the cylinder head cover 18. As a result, a cooling air passage 148 through which the cooling air 149 flows from the cooling fan 9 (see FIG. 3, etc.) disposed at the rear of the engine 1 is formed between the support base 121 and the cylinder head cover 18. Therefore, the cooling air 149 from the cooling fan 9 can be guided to the front side of the cylinder head 2 through the cooling air passage 148, and the periphery of the front side of the cylinder head 2 can be appropriately cooled. In this embodiment, the EGR cooler 27 and the exhaust pressure sensor 151 described later are attached to the front side of the cylinder head 2, so that the cooling air 149 guided from the cooling fan 9 to the front side of the cylinder head 2 through the cooling air passage 148 can promote cooling of the EGR cooler 27 and prevent thermal damage to the exhaust pressure sensor 151.

Next, the configuration of the periphery of the front side of the cylinder head 2 will be described with reference to Figures 17 to 21. As shown in Figure 21, the cylinder head 2 is formed with a plurality of intake passages 36 that introduce fresh air into a plurality of intake ports (not shown) and a plurality of exhaust passages 37 that guide exhaust gas from a plurality of exhaust ports. An intake manifold 3 that brings together the plurality of intake passages 36 is formed integrally with the right side of the cylinder head 2. By constructing the cylinder head 2 and the intake manifold 3 integrally, it is possible to improve the gas sealing from the intake manifold 3 to the intake passages 36 and to increase the rigidity of the cylinder head 2.

On the right side of the exhaust manifold 4 connected to the left side of the cylinder head 2, an EGR gas outlet 41 communicating with the upstream EGR gas passage 31 in the cylinder head 2 and an exhaust inlet 42 communicating with the multiple exhaust passages 37 are opened in a line in the front-rear direction. An exhaust manifold 43 communicating with the EGR gas outlet 41 and the exhaust inlet 42 is formed in the exhaust manifold 4. An exhaust manifold exhaust outlet 49 communicating with the exhaust collection part 43 is opened at the rear of the left side of the exhaust manifold 4. When exhaust gas from the exhaust passage 37 of the cylinder head 2 flows into the exhaust collection part 43 through the exhaust inlet 42, a part of the exhaust gas flows as EGR gas from the EGR gas outlet 41 into the upstream EGR gas passage 31 in the cylinder head 2, and the rest of the exhaust gas flows from the exhaust manifold exhaust outlet 49 into the two-stage turbocharger 30 (see FIG. 7, etc.).

The exhaust manifold 4 is connected to the left side (exhaust side) of the cylinder head 2, which is opposite to the right side (intake side) on which the intake manifold 3 is integrally molded, and the EGR cooler 27 is connected to the front side (one of the two sides intersecting the exhaust side). Left and right EGR cooler connecting parts 33, 34 protrude forward from both left and right edges of the front side of the cylinder head 2 (the left front corner and the right front corner of the cylinder head 2). The EGR cooler 27 is connected to the front sides of the left and right EGR cooler connecting parts 33, 34. EGR gas passages 31, 32 and cooling water passages 38, 39 are formed in the EGR cooler connecting parts 33, 34.

By configuring the EGR gas passages 31, 32 and the cooling water passages 38, 39 in the EGR cooler connection parts 33, 34, it is not necessary to provide cooling water piping and EGR gas piping between the EGR cooler 27 and the cylinder head 2. Therefore, not only can the sealing performance at the connection part with the EGR cooler 27 be ensured without being affected by the expansion and contraction of the piping due to EGR gas or cooling water, but resistance (structural stability) to external variables such as heat and vibration is improved, and a compact configuration can be achieved.

17, 20 and 21, an upstream EGR gas passage 31 is provided in the left EGR cooler connection part 33, and a downstream EGR gas passage 32 is provided in the right EGR cooler connection part 34. The upstream EGR gas passage 31 is approximately L-shaped in a plan view, and one end and the other end are open on the front side and the left side of the left EGR cooler connection part 33, and connects the lower left part of the back surface of the EGR cooler 27 to the EGR gas outlet 41 provided in the front part of the right side of the exhaust manifold 4. The downstream EGR gas passage 32 is approximately L-shaped in a plan view, and one end and the other end are open on the front side and the right side of the right EGR cooler connection part 34, and connects the upper right part of the back surface of the EGR cooler 27 to the EGR gas inlet of the recirculation exhaust gas piping 28.

In the left EGR cooler connecting portion 33, a downstream cooling water passage 38 is formed, which is guided from the front side of the left EGR cooler connecting portion 33 to the rear side. The downstream cooling water passage 38 is provided above the upstream EGR gas passage 31, and sends the cooling water discharged from the upper left part of the back surface of the EGR cooler 27 to the cooling water passage in the cylinder head 2. In addition, in the right EGR cooler connecting portion 34, an upstream cooling water passage 39 is formed, which is guided from the front side of the right EGR cooler connecting portion 34 to the rear side. The upstream cooling water passage 39 is provided below the downstream EGR gas passage 32, and sends the cooling water flowing through the cooling water passage in the cylinder head 2 to the lower right part of the back surface of the EGR cooler 27.

As shown in Figures 17 to 20, an exhaust pressure sensor 151 that detects the exhaust gas pressure in the exhaust manifold 4 is provided on the front side of the cylinder head 2. The exhaust pressure sensor 151 is attached to an exhaust pressure sensor attachment portion 152 that protrudes forward from a central upper portion of the front side of the cylinder head 2. The exhaust pressure sensor attachment portion 152 is provided between the left and right EGR cooler connecting portions 33, 34. In the engine 1 of this embodiment, the left edge of the exhaust pressure sensor attachment portion 152 is formed continuous with a portion of the right edge of the left EGR cooler connecting portion 33 near the upper portion.

The exhaust pressure sensor 151 is connected to the exhaust manifold 4 via an exhaust pressure bypass path 153 provided in the cylinder head 2 and an exhaust pressure detection pipe 154 that connects the exhaust pressure bypass path 153 and the exhaust manifold 4. The exhaust pressure bypass path 153 is drilled from the front end portion of the left side surface of the cylinder head 2 toward the right side, and is led to the inside of the exhaust pressure sensor mounting part 152 through the inside of the left EGR cooler connection part 33. The exhaust pressure bypass path 153 is also bent toward the front side within the exhaust pressure sensor mounting part 152 and opens to the front side surface of the exhaust pressure sensor mounting part 152. A hole filling member 155 that closes the end of the exhaust pressure bypass path 153 is attached to the front side surface of the exhaust pressure sensor mounting part 152.

As shown in FIG. 18, the exhaust pressure sensor mounting portion 152 has a sensor mounting hole 152a drilled downward from its upper surface and connected to the exhaust pressure bypass path 153. When the exhaust pressure sensor 151 is attached to the sensor mounting hole 152a, the lower end of the exhaust pressure sensor 151 is exposed to the exhaust pressure bypass path 153.

On the other hand, the exhaust pressure detection pipe 154 is disposed above the exhaust manifold 4, to the left of the front part of the left side surface of the cylinder head 2. A detection pipe mounting base 156 is provided protruding upward from the front part of the upper surface of the exhaust manifold 4. A rear joint member 157 is attached to the upper surface of the detection pipe mounting base 156. A front joint member 158 is attached to the end of the exhaust pressure bypass path 153 that opens at the front end portion of the left side surface of the cylinder head 2. The front end of the exhaust pressure detection pipe 154 is connected to the exhaust pressure bypass path 153 via the front joint member 158. The rear end of the exhaust pressure detection pipe 154 is connected to the exhaust manifold 4 exhaust collector 43 (see FIG. 21) in the exhaust manifold 4 via the rear joint member 157. An exhaust gas temperature sensor 159 is attached to the upper surface of the detection pipe mounting base 156, at a position forward of the rear joint member 157. The exhaust gas temperature sensor 159 detects the temperature of the exhaust gas flowing through the exhaust collection section 43 in the exhaust manifold 4.

The heat transferred from the exhaust manifold 4, which becomes hot, to the exhaust pressure detection pipe 154 is diffused in the cylinder head 2 via the front joint member 158. This prevents the heat of the exhaust manifold 4 and the exhaust pressure detection pipe 154 from being directly transferred to the exhaust pressure sensor 151, which is sensitive to heat. Therefore, the length of the exhaust pressure detection pipe 154 can be shortened while preventing the exhaust pressure sensor 151 from failing or malfunctioning due to the heat of the exhaust manifold 4 and the exhaust pressure detection pipe 154. In addition, shortening the length of the exhaust pressure detection pipe 154 improves the reliability of the exhaust pressure detection pipe 154 and makes it easier to arrange the exhaust pressure detection pipe 154, reducing the number of design steps and improving the manufacturability and assembly of the engine 1.

17 and 20, the downstream cooling water passage 38 is provided in the left EGR cooler connection portion 33 near the exhaust pressure bypass path 153, so that the gas temperature in the exhaust pressure bypass path 153 can be efficiently reduced. Therefore, the exhaust pressure bypass path 153 can be shortened while keeping the heat transferred from the gas in the exhaust pressure bypass path 153 to the exhaust pressure sensor 151 within an allowable range, and the exhaust pressure bypass path 153 to the cylinder head 2 can be easily formed. In addition, the exhaust pressure bypass path 153 passes through the left EGR cooler connection portion 33 and the inside of the exhaust pressure sensor mounting portion 152 protruding from the front side surface of the cylinder head 2, so that the gas in the exhaust pressure bypass path 153 can be efficiently cooled, and the breakdown or malfunction of the exhaust pressure sensor 151 caused by heat can be prevented. Furthermore, the exhaust pressure sensor 151 is attached to an exhaust pressure sensor attachment portion 152 that protrudes from the front side of the cylinder head 2 between a pair of EGR cooler connection portions 33, 34, so that the exhaust pressure sensor 151 can be efficiently cooled and failure or malfunction of the exhaust pressure sensor 151 caused by heat can be prevented.

As shown in FIG. 19, the mounting position of the front joint member 158 is higher than the upper surface of the detection pipe mounting base 156. The exhaust pressure detection pipe 154 extends from the rear joint member 157 diagonally forward to the left, then bypasses the exhaust gas temperature sensor 159 and is led diagonally upward while curving to the right, and then is arranged approximately horizontally forward along the left side surface of the cylinder head 2 and connected to the front joint member 158. The end of the exhaust pressure detection pipe 154 on the front joint member 158 side is arranged at a higher position than the end on the rear joint member 157 side. Therefore, it is possible to prevent oil and moisture contained in the exhaust gas from becoming liquid in the exhaust pressure detection pipe 154 and entering the exhaust pressure bypass path 153, and the exhaust gas pressure can be accurately detected.

As shown in Figures 17 to 21, by configuring the EGR cooler connection parts 33, 34 to protrude, it is not necessary to have piping for EGR gas that connects the exhaust manifold 4, the EGR cooler 27, and the EGR device 24, and the number of connection points in the EGR gas passage is reduced. Therefore, in the engine 1 that aims to reduce NOx due to EGR gas, not only can EGR gas leakage be reduced, but deformation due to stress changes caused by expansion and contraction of the piping can be suppressed. In addition, since the EGR gas passages 31, 32 and the cooling water passages 38, 39 are formed in the EGR cooler connection parts 33, 34, the shapes of each passage 31, 32, 38, 39 formed in the cylinder head 2 are simplified, so the cylinder head 2 can be easily cast without using a complex core.

In addition, since the left EGR cooler connection part 33 on the exhaust manifold 4 side and the right EGR cooler connection part 34 on the intake manifold 3 side are spaced apart, mutual influence due to thermal deformation at each of the EGR cooler connection parts 33, 34 can be suppressed. Therefore, not only can gas leakage, cooling water leakage, damage, etc. be prevented at the connection part between the EGR cooler connection parts 33, 34 and the EGR cooler 27, but also the rigidity balance of the cylinder head 2 can be maintained. In addition, since the volume at the front side 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 of the cylinder head 2 and a configuration with spaces in front and behind the EGR cooler 27 can be configured, cooling air can be circulated around the EGR cooler 27, and the cooling efficiency of the EGR cooler 27 can be improved.

As shown in FIG. 17, the downstream cooling water passage 38 and the upstream EGR gas passage 31 are arranged vertically in the left EGR cooler connection 33, and the downstream EGR gas passage 32 and the upstream cooling water passage 39 are arranged vertically in the right EGR cooler connection 34. The cooling water inlet of the downstream cooling water passage 38 and the EGR gas inlet of the downstream EGR gas passage 32 are arranged at the same height, while the cooling water outlet of the upstream cooling water passage 39 and the EGR gas outlet of the downstream EGR gas passage 32 are arranged at the same height.

By providing the EGR gas passages 31, 32 and the cooling water passages 38, 39 inside the EGR cooler connecting parts 33, 34 that are separately protruding, the effects of thermal deformation in both EGR cooler connecting parts 33, 34 are mitigated. In addition, in the EGR cooler connecting parts 33, 34, the EGR gas flowing through the EGR gas passages 31, 32 is cooled by the cooling water flowing through the cooling water passages 38, 39, and the thermal deformation itself in the EGR cooler connecting parts 33, 34 is also suppressed. Furthermore, in each of the EGR cooler connecting parts 33, 34, the EGR gas passages 31, 32 and the cooling water passages 38, 39 are arranged with their vertical height positions swapped. Therefore, the heat distribution in the EGR cooler connecting parts 33, 34 is vertically reversed, and the effects of thermal deformation in the height direction in the cylinder head 2 can be reduced.

Next, a portion of the harness structure arranged around the front side surface of the cylinder head 2 will be described with reference to Figures 22 and 23. In the engine 1 of this embodiment, a harness assembly 171 bundling multiple harnesses is arranged in the front-rear direction along the right side surface of the cylinder head cover 18. The harness assembly 171 branches off from a main harness assembly (not shown) that extends from an external connection harness connector (not shown) attached to the engine 1.

The front end of the harness assembly 171 is disposed between the cylinder head cover 18 and the intake side leg 121e of the support base 121. The harness assembly 171 branches into an EGR valve harness 172, an EGR gas temperature sensor harness 173, and a sensor harness assembly 174 near the right front corner of the cylinder head cover 18. The EGR valve harness 172 passes between the second center leg 121d and the intake side leg 121e of the support base 121 and is electrically connected to the EGR valve member 29. The EGR gas temperature sensor harness 173 passes between the second center leg 121d and the intake side leg 121e and is electrically connected to the EGR gas temperature sensor 181 that detects the exhaust gas temperature in the recirculation exhaust gas pipe 28.

The sensor harness assembly 174 is led from the harness assembly 171 toward the left side and bent downward in front of the right portion of the front side of the cylinder head cover 18. The front end of the sensor harness assembly 174 branches into a rotation angle sensor harness assembly 175 and an exhaust pressure sensor harness 176. The exhaust pressure sensor harness 176 is led from the harness assembly 174 toward the left side, passing between the cylinder head cover 18 and the first central leg 121c of the support base 121, and is electrically connected to the exhaust pressure sensor 151.

The rotation angle sensor harness assembly 175 extends downward from the sensor harness assembly 174 along the front side surface of the cylinder head 2. The rotation angle sensor harness assembly 175 is bent toward the left side directly above the flywheel housing 7 and led to a position forward of the lower left corner of the front side surface of the cylinder head 2. The rotation angle sensor harness assembly 175 branches into a crankshaft rotation angle sensor harness 177 and a camshaft rotation angle sensor harness 178. The crankshaft rotation angle sensor harness 177 is electrically connected to a crankshaft rotation angle sensor 182 (see FIG. 1) attached to the upper left portion of the front part of the flywheel housing 7. The camshaft rotation angle sensor harness 178 is electrically connected to a camshaft rotation angle sensor 183 (see FIG. 1) attached to the upper left edge of the flywheel housing 7.

As shown in FIG. 17, locking member mounting portions 185, 186 are formed in the center of the left and right sides of the front side of the cylinder head 2, aligned vertically. The upper locking member mounting portion 185 is located near the top of the front side of the cylinder head 2, between the right EGR cooler connecting portion 34 and the first central mounting portion 123c. The lower locking member mounting portion 186 is located near the bottom of the front side of the cylinder head 2, directly below the upper locking member mounting portion 185, between the left and right EGR cooler connecting portions 33, 34.

22 and 23, the rotation angle sensor harness assembly 175, which faces the front side of the cylinder head 2, is attached to the front side of the cylinder head 2 by locking members 187, 188 attached to upper and lower locking member mounting portions 185, 186. The rotation angle sensor harness assembly 175 is then guided from the harness assembly 174 through the gap between the right EGR cooler connecting portion 34 and the first central leg portion 121c of the support base 121, and between the cylinder head 2 and the EGR cooler 27, to a position facing the lower edge of the front side of the cylinder head 2.

The EGR cooler 27 is attached to a pair of left and right EGR cooler connectors 33, 34 that protrude forward from the front side surface of the cylinder head 2. A space is formed between the rear surface of the EGR cooler 27 and the cylinder head 2. By disposing the rotation angle sensor harness assembly 175 in the vertical direction in this space, the rotation angle sensor harness assembly 175 can be protected and the layout design of the rotation angle sensor harness assembly 175 becomes easier.

In addition, a space is formed between the side surface of the cylinder head cover 18 and the support base 121. By utilizing this space to arrange the harness assemblies 171, 174 and the harnesses 172, 173, 176, these harnesses and harness assemblies can be protected and the layout design of the harnesses can be made easier.

As shown in Figures 1 to 10, the engine 1 includes an exhaust manifold 4 provided on the exhaust side (e.g., the left side), which is one side of the cylinder head 2, and a two-stage turbocharger 30 driven by exhaust gas discharged from the exhaust manifold 4. The two-stage turbocharger 30 is composed of a high-pressure stage turbocharger 51 connected to the exhaust manifold 4 and a low-pressure stage turbocharger 52 connected to the high-pressure stage turbocharger 51. The high-pressure stage turbocharger 51 is disposed on the side of the exhaust manifold 4, and the low-pressure stage turbocharger 52 is disposed above the exhaust manifold 4, so that the exhaust manifold 4 and the two-stage turbocharger 30 can be compactly disposed within a substantially rectangular frame, and the engine 1 can be made compact. Furthermore, the high-pressure stage exhaust outlet 58 of the high-pressure stage turbocharger 51 and the low-pressure stage exhaust inlet 60 of the low-pressure stage turbocharger 52 are connected via a high-pressure exhaust gas pipe 59, which is an example of a flexible pipe, so that the risk of low-cycle fatigue failure of the high-pressure exhaust gas pipe 59 due to thermal expansion can be reduced.

In the engine 1, the low-pressure stage turbocharger 52 is fixed to the exhaust side of the cylinder head 2, and the high-pressure stage turbocharger 51 is fixed to the exhaust manifold 4, so that the high-pressure stage turbocharger 51 and the low-pressure stage turbocharger 52 constituting the two-stage turbocharger 30 can be firmly fixed to the robust cylinder head 2 and exhaust manifold 4. Furthermore, the high-pressure stage exhaust outlet 58 of the high-pressure stage turbocharger 51 and the low-pressure stage exhaust inlet 60 of the low-pressure stage turbocharger 52 are connected via a flexible high-pressure exhaust gas piping 59, so that the stress applied to the two-stage turbocharger 30 due to the thermal expansion of the high-pressure exhaust gas piping 59 can be reduced. This reduces the stress applied to the connection between the high-pressure stage turbocharger 51 and the exhaust manifold 4 and the connection between the low-pressure stage turbocharger 52 and the cylinder head 2, and prevents poor connection at these connections and damage to the connection members.

Furthermore, the cylinder head 2 is provided with a rib 135 extending from the low-pressure stage turbocharger mounting portion 131 on the exhaust side toward the intake side (e.g., the right side) opposite the exhaust side. This improves the rigidity of the area around the low-pressure stage turbocharger mounting portion 131 in the cylinder head 2, and prevents deformation of the cylinder head 2 caused by mounting the low-pressure stage turbocharger 52 to the cylinder head 2.

The engine 1 also includes an exhaust gas purification device 100 that purifies exhaust gas from the engine 1. The exhaust gas inlet pipe 116 as an exhaust inlet of the exhaust gas purification device 100 is disposed near the corner where one of the two sides of the cylinder head 2 that intersect with the exhaust side intersects with the exhaust side, and the low-pressure stage turbocharger 52 is disposed closer to the one side as viewed from the exhaust side, and the low-pressure stage exhaust outlet 61 of the low-pressure stage turbocharger 52 is provided toward the one side. Therefore, the engine 1 can shorten and simplify the exhaust connection pipe 119 and exhaust connection member 120 as an example of a pipe connecting the low-pressure stage exhaust outlet 61 of the low-pressure stage turbocharger 52 and the exhaust gas inlet pipe 116 of the exhaust gas purification device 100. This allows the exhaust gas supplied to the exhaust gas purification device 100 to be maintained at a high temperature, and prevents a decrease in the regeneration ability of the exhaust gas purification device 100.

Furthermore, above the cylinder head 2, the blow-by gas outlet 70 of the blow-by gas reduction device 19 is disposed toward the exhaust side at a position toward the other side opposite to the one side of the cylinder head 2, and the low-pressure stage fresh air inlet 63 of the low-pressure stage turbocharger 52 is provided toward the other side. Also, the blow-by gas outlet 70 is connected to the intake pipe 62 connected to the low-pressure stage fresh air inlet 63 of the low-pressure stage turbocharger 52 via a return hose 68. Therefore, in the engine 1, by disposing both the blow-by gas outlet 70 of the blow-by gas reduction device 19 and the intake pipe 62 connected to the low-pressure stage fresh air inlet 63 of the low-pressure stage turbocharger 52 at a position toward the other side of the cylinder head 2, the return hose 68 can be shortened, and measures against freezing inside the return hose 68 are not required.

As shown in Figures 1 to 5 and 11 to 16, the engine 1 is provided with an exhaust gas purification device 100 via a support stand 121 above the cylinder head 2. The support stand 121 has a flat portion 121a on which the exhaust gas purification device 100 is mounted, and a number of legs 121b, 121c, 121d, and 121e that protrude downward from the flat portion 121a and are fixed to the cylinder head 2. The flat portion 121a and the legs 121b, 121c, 121d, and 121e are integrally molded. In addition, the spaces between the legs 121b, 121c, 121d, and 121e are formed in an arch shape. Therefore, the integrally molded structure and arch shape ensure the rigidity of the support stand 121 while realizing a reduction in weight. In addition, by making the support stand 121 an integrally molded part, the number of parts can be reduced. In addition, by forming arch-shaped gaps between the multiple legs 121b, 121c, 121d, and 121e, it is possible to prevent heat pools from forming around the legs of the support base 121, and to prevent heat damage to electronic components such as the exhaust pressure sensor 151, which is an example of a sensor mounted around the legs, and to prevent insufficient cooling of cooling components such as the EGR cooler 27.

The engine 1 is configured such that the exhaust manifold 4 and the intake manifold 3 are distributed and arranged on the exhaust side and the intake side of the cylinder head 2, which face each other. The support base 121 is arranged above one of the two sides of the cylinder head 2 that intersect with the axial direction of the crankshaft 5, and has, as legs, an exhaust side leg 121b fixed to the exhaust side, an intake side leg 121e fixed to the intake side, and central legs 121c, 121d fixed to the one side. Therefore, the engine 1 can fix the support base 121 to a total of three sides of the cylinder head 2, the exhaust side, the intake side, and the one side, and the support rigidity of the exhaust gas purification device 100 can be improved. In addition, by making the height and size of the arch shapes between the exhaust side leg 121b and the first central leg 121c and between the intake side leg 121e and the second central leg 121d different, and by making the lengths of the exhaust side leg 121b and the intake side leg 121e different, it becomes possible for the support base 121 to cancel out the vibrations of the intake side and exhaust side, thereby reducing the vibration of the exhaust gas purification device 100.

The engine 1 is also configured to include a cooling fan 9 on the other of the two sides of the cylinder head 2. A cooling air passage 148 through which cooling air 149 from the cooling fan 9 flows is formed between the cylinder head cover 18 on the cylinder head 2 and the support base 121. Therefore, the engine 1 can guide the cooling air from the cooling fan 9 to the one side of the cylinder head 2 via the cooling air passage 148, and can properly cool the periphery of the one side of the cylinder head 2.

The engine 1 further includes an EGR device 24 that returns a portion of the exhaust gas discharged from the exhaust manifold 4 to the intake manifold 3 as EGR gas, an EGR cooler 27 that cools the EGR gas, and an exhaust pressure sensor 151 that detects the exhaust gas pressure in the exhaust manifold 4. The EGR cooler 27 and the exhaust pressure sensor 151 are attached to the one side surface of the cylinder head 2. Therefore, the cooling air 149 guided from the cooling fan 9 to the one side surface through the cooling air passage 148 can promote cooling of the EGR cooler 27 and prevent thermal damage to the exhaust pressure sensor 151.

In addition, in the engine 1, the intake manifold 3 is integrally molded on the intake side of the cylinder head 2, and the intake side leg 121e is fixed to the upper surface of the intake manifold 3, so that the intake side leg 121e can be placed on the robust intake manifold 3 and firmly fixed thereon. In addition, since the bolts for fixing the intake side leg 121e to the intake manifold 3 can be tightened and loosened from above the cylinder head 2, the installation and removal of the support base 121 can be performed with the EGR device 24, which is arranged to the side of the intake side of the cylinder head 2, attached to the intake manifold 3, improving the ease of assembly and maintenance of the engine 1.

As shown in Figures 1 to 5 and Figures 17 to 21, the engine 1 is equipped with an exhaust manifold 4 provided on the exhaust side of the cylinder head 2, and an exhaust pressure sensor 151 that detects the exhaust gas pressure in the exhaust manifold 4. The exhaust pressure sensor 151 is attached to the cylinder head 2, and the exhaust manifold 4 and the exhaust pressure sensor 151 are connected via an exhaust pressure bypass path 153 provided in the cylinder head 2 and an exhaust pressure detection pipe 154 that connects the exhaust pressure bypass path 153 and the exhaust manifold 4, so that the heat of the exhaust pressure detection pipe 154 can be diffused by the cylinder head 2. Therefore, the engine 1 can shorten the length of the exhaust pressure detection pipe 154 while preventing the failure or malfunction of the exhaust pressure sensor 151 caused by the heat of the exhaust manifold 4 and the exhaust pressure detection pipe 154. Furthermore, by shortening the length of the exhaust pressure detection pipe 154, the reliability of the exhaust pressure detection pipe 154 is improved and the arrangement of the exhaust pressure detection pipe 154 is made easier, which reduces the number of design steps and improves the manufacturability and assembly of the engine 1. Furthermore, in the engine 1, the cooling water passage 38 is provided in the cylinder head 2 near the exhaust pressure bypass path 153, so the gas temperature in the exhaust pressure bypass path 153 can be efficiently reduced. Therefore, the engine 1 can shorten the exhaust pressure bypass path 153 while keeping the heat transferred from the gas in the exhaust pressure bypass path 153 to the exhaust pressure sensor 151 within an allowable range, making it easy to form the exhaust pressure bypass path 153 to the cylinder head 2.

The engine 1 is configured to include an EGR device 24 that returns a portion of the exhaust gas discharged from the exhaust manifold 4 to the intake manifold 3 as EGR gas, and an EGR cooler 27 that cools the EGR gas. The cylinder head 2 includes a pair of EGR cooler connectors 33, 34 that protrude from one of the two sides of the cylinder head 2 that intersect with the exhaust side. The cooling water passage 38 passes through one of the EGR cooler connectors 33 and is connected to the EGR cooler 37, and the exhaust pressure bypass path 153 passes through the EGR cooler connector 33. Therefore, the engine 1 can efficiently cool the gas in the exhaust pressure bypass path 153, and can prevent the exhaust pressure sensor 151 from breaking down or malfunctioning due to heat.

Furthermore, the exhaust pressure sensor 151 is attached to an exhaust pressure sensor attachment portion 152 that protrudes from one side surface of the cylinder head 2 between the pair of EGR cooler connection portions 33, 34. Therefore, the engine 1 can efficiently cool the exhaust pressure sensor 151, and can prevent breakdowns or malfunctions of the exhaust pressure sensor 151 caused by heat.

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 spirit of the present invention.

(Additional Note)
(Appendix 1)
An engine system including an exhaust manifold provided on an exhaust side of a cylinder head and an exhaust pressure sensor for detecting an exhaust gas pressure in the exhaust manifold,
The exhaust pressure sensor is attached to the cylinder head,
the exhaust manifold and the exhaust pressure sensor are connected via an exhaust pressure bypass path provided in the cylinder head and an exhaust pressure detection pipe connecting the exhaust pressure bypass path and the exhaust manifold;
a cooling water passage is provided in the cylinder head near the exhaust pressure bypass path;
Engine equipment.

(Appendix 2)
The exhaust gas recirculation (EGR) device returns a portion of the exhaust gas discharged from the exhaust manifold to the intake manifold as EGR gas, and an EGR cooler cools the EGR gas,
The cylinder head includes a pair of EGR cooler connecting portions protruding from one of two side surfaces of the cylinder head intersecting the exhaust side surface,
The cooling water passage is connected to the EGR cooler through one of the EGR cooler connection parts,
The exhaust pressure bypass path passes through the one of the EGR cooler connection parts.
2. The engine apparatus of claim 1.

(Appendix 3)
The exhaust pressure sensor is attached to an exhaust pressure sensor attachment portion that protrudes from the one side surface of the cylinder head between the pair of EGR cooler connection portions.
3. The engine apparatus according to claim 2.

The engine device described in Appendix 1 is an engine device equipped with an exhaust manifold provided on the exhaust side of the cylinder head and an exhaust pressure sensor that detects the exhaust gas pressure in the exhaust manifold, and the exhaust pressure sensor is attached to the cylinder head, and the exhaust manifold and the exhaust pressure sensor are connected via an exhaust pressure bypass path provided in the cylinder head and an exhaust pressure detection pipe that connects the exhaust pressure bypass path and the exhaust manifold, so that the heat of the exhaust pressure detection pipe can be diffused by the cylinder head. Therefore, the engine device of the present invention can shorten the length of the exhaust pressure detection pipe while preventing failure or malfunction of the exhaust pressure sensor caused by the heat of the exhaust manifold and the exhaust pressure detection pipe. And, by shortening the length of the exhaust pressure detection pipe, the reliability of the pipe is improved and the arrangement of the pipe is made easier, thereby reducing the design man-hours and improving the manufacturability and assembly of the engine device. Furthermore, in the engine device of the present invention, a cooling water passage is provided in the cylinder head near the exhaust pressure bypass path, so that the gas temperature in the exhaust pressure bypass path can be efficiently reduced. Therefore, the engine device of the present invention can shorten the exhaust pressure bypass path while keeping the heat transferred from the gas in the exhaust pressure bypass path to the exhaust pressure sensor within an acceptable range, making it easy to form the bypass path to the cylinder head while preventing failure or malfunction of the exhaust pressure sensor due to heat.

In the engine device described in Appendix 1, for example, an EGR device that returns a portion of the exhaust gas discharged from the exhaust manifold to the intake manifold as EGR gas, and an EGR cooler that cools the EGR gas are provided, and the cylinder head has a pair of EGR cooler connectors protruding from one of the two sides of the cylinder head that intersect with the exhaust side, the cooling water passage passes through one of the EGR cooler connectors and is connected to the EGR cooler, and the exhaust pressure bypass path passes through the one of the EGR cooler connectors, so that the gas in the exhaust pressure bypass path can be efficiently cooled and heat-induced breakdowns and malfunctions of the exhaust pressure sensor can be prevented.

Furthermore, if the exhaust pressure sensor is attached to an exhaust pressure sensor mounting portion that protrudes from one side of the cylinder head between a pair of EGR cooler connection portions, the exhaust pressure sensor can be cooled efficiently, and breakdowns or malfunctions of the exhaust pressure sensor caused by heat can be prevented.

1. Engine (engine device)
2 Cylinder head 3 Intake manifold 4 Exhaust manifold 30 Two-stage turbocharger 51 High-pressure stage turbocharger 52 Low-pressure stage turbocharger 59 High-pressure exhaust gas piping (flexible piping)
131 Low pressure stage turbocharger mounting portion 135 Rib 100 Exhaust gas purification device 116 Exhaust gas inlet pipe (exhaust inlet of exhaust gas purification device)
19 Blow-by gas reduction device 70 Blow-by gas outlet 63 Low-pressure stage fresh air inlet (fresh air inlet of low-pressure stage turbocharger)
62 Air intake pipe 68 Return hose

Claims (4)

An engine device including an exhaust manifold provided on an exhaust side of a cylinder head, an exhaust pressure sensor for detecting exhaust gas pressure , and a cooling fan ,
The exhaust pressure sensor is attached to the cylinder head ,
A portion of the exhaust pressure sensor is exposed to the outside of the cylinder head.
Engine equipment. The exhaust pressure sensor is provided in an exhaust pressure detection path provided in the cylinder head.
The engine apparatus according to claim 1 . an exhaust pressure detection pipe connecting the exhaust pressure detection path and the exhaust manifold;
The engine device according to claim 2. a cooling water passage is provided in the cylinder head near the exhaust pressure detection passage;
The engine device according to claim 2 or 3.