JP5898714B2 - Engine equipment - Google Patents

Description

  The present invention relates to an engine device equipped with an exhaust gas purification device that removes particulate matter (soot, particulates) and the like contained in exhaust gas.

  Conventionally, a diesel particulate filter (hereinafter referred to as DPF) is provided as an exhaust gas purification device (post-treatment device) in the exhaust path of a diesel engine, and the exhaust gas discharged from the diesel engine is purified by the DPF. Is known (see, for example, Patent Documents 1 to 3). Further, in the DPF, a technique is also known in which an inner case (filter case) is provided in an outer case (casing), and a filter member such as an oxidation catalyst or a soot filter is disposed in the inner case (see, for example, Patent Document 4). .

JP 2000-145430 A Japanese Patent Laid-Open No. 2003-27922 JP 2008-82201 A JP 2001-173429 A

  In a structure with a plurality of inner cases each containing a filter member and a plurality of outer cases each containing a respective inner case, when each outer case is connected in a separable manner, it is welded to the joining side of each outer case. In many cases, adjacent flanges are overlapped with each other and bolted together. However, in the structure in which the flange body is welded and fixed to each outer case as described above, for example, when a DPF is directly mounted on a diesel engine, the vibration and stress of the diesel engine are applied to each outer case, and the outer case and the flange Stress concentration occurs in the welds. As a result of such stress concentration, there has been a problem that the welded portion is easily broken or the outer case is easily deformed or damaged. In addition, due to welding distortion, the flatness of each flange body may be low (the plane of each flange body may be distorted), and the possibility of exhaust gas leakage from overlapping portions of the flange bodies cannot be completely wiped out. There was also a concern.

  Therefore, the present invention has a technical problem to provide an engine device that has been improved by examining these current conditions.

The present invention is an engine device having an engine and an exhaust gas purification device having a filter for purifying exhaust gas exhausted from the engine, wherein the exhaust gas purification device has an inner case in which the filter is incorporated. And an outer case that houses the inner case, and a differential pressure sensor that detects a clogged state inside the apparatus, the inner case being connected to the outer case via a joint flange that protrudes to the outer peripheral side of the outer case. A plurality of combinations of the filter, the inner case, and the outer case are provided, and the plurality of outer cases are connected by fixing the joint flange with a pair of holding flanges. And a support for fastening the outer case to the engine is fastened to at least one of the holding flanges. Attach the detecting body of the differential pressure sensor to the sensor bracket fixed to a front side surface of the cylinder head of the engine, it is that was placed above the said cylinder head.

  According to the present invention, since the differential pressure sensor can be disposed at a position separated from the exhaust gas purification device, failure of the differential pressure sensor due to heating can be suppressed. In addition, since the differential pressure sensor can be placed relatively close to the exhaust gas purification device, the length of the sensor piping connecting the differential pressure sensor and the exhaust gas purification device can be set short to improve assembly workability and reduce costs. realizable.

  According to the present invention, there is provided an exhaust gas purification device comprising a plurality of gas purification filters for purifying exhaust gas from an engine and a plurality of cases for accommodating the gas purification filters, wherein the adjacent cases are Since the joining flanges that protrude to the outer peripheral side are abutted and connected by clamping the two joining flanges in the abutting direction with a pair of sandwiching flanges, the sandwiching flanges are constructed separately without welding to the case. become. For this reason, in the relationship between the clamping flange and the case, problems of stress concentration and distortion caused by welding can be avoided. A substantially uniform pressure contact force can be applied to both of the joint flanges, and the surface pressure of the sealing surface (clamping surface) of the sandwich flange can be maintained at a high level, and exhaust gas leakage from between the joint flanges can be reliably prevented. .

  Each case includes an inner case containing the gas purification filter and an outer case containing the inner case, and the inner case and the outer case are fixed via the joint flange. Therefore, the joining flange can be used as a member for connecting adjacent cases. Contributes to improving the connection strength between the inner case and the outer case.

It is a top view of a diesel engine. It is a side view of the intake manifold installation side of a diesel engine. It is a side view of the exhaust manifold installation side of a diesel engine. It is a side view of the cooling fan installation side of a diesel engine. It is a side view of the flywheel housing installation side of a diesel engine. It is a section explanatory view of DPF. It is fuel system explanatory drawing of a diesel engine. It is a principal part enlarged side view of a common rail system. FIG. 6 is an enlarged side view around the intake manifold. FIG. 3 is an enlarged plan view around an intake manifold. It is a top sectional view showing the relation between an intake manifold and a collector. It is an enlarged plan view showing the connection relationship between the recirculation exhaust gas pipe and the EGR valve member. It is an enlarged side view by the side of the cooling fan installation which shows a ventilation path. (A) is a perspective view of an intermediate joint, (b) is a side view of the intermediate joint viewed from the EGR valve member side. It is a plane sectional view of an intermediate joint. It is a principal part expanded side view which shows the relationship between a common rail, a collector, etc. seen from the intake manifold installation side. It is a principal part expanded side view which shows the relationship between the common rail and fuel pump seen from the cooling fan installation side. It is a schematic perspective view which shows the relationship between a common rail, an intake manifold, and a fuel injection pump. It is a schematic plan view which shows the relationship between a common rail and a fuel injection pump. FIG. 3 is an enlarged side view of a main part showing a relationship between a common rail, a collector, and the like as viewed from the intake manifold installation side in a three-cylinder type diesel engine. FIG. 3 is an enlarged side view of a main part showing a relationship between a common rail and a fuel pump viewed from a cooling fan installation side in a three-cylinder diesel engine. FIG. 3 is an enlarged side view of an essential part of an example in which a positional relationship of a common rail with respect to a fuel pump is made the same as that in a four-cylinder type in a three-cylinder type diesel engine. It is an external appearance top view of DPF. DPF appearance side view It is an external appearance side view of the upstream of DPF It is a cross-sectional side view of the downstream of DPF. It is decomposition | disassembly cross-section explanatory drawing of DPF. It is a separation side view of a clamping flange (unit). (A) is an enlarged side sectional view of the catalyst side joining flange in the embodiment, (b) is an enlarged side sectional view of the catalyst side joining flange in the first example, and (c) is a catalyst side joining flange in the second example. It is an expanded side sectional view.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(1). Overall Structure of Diesel Engine First, the overall structure of a common rail type diesel engine 70 will be described mainly with reference to FIGS. In the following description, both sides parallel to the crank axis a (sides on both sides of the crank axis a) are referred to as left and right, the flywheel housing 78 installation side is referred to as the front side, and the cooling fan 76 installation side is referred to as the rear side. For convenience, these are used as a reference for the positional relationship between the four sides and the top and bottom of the diesel engine 70.

  As shown in FIGS. 1 to 3, the diesel engine 70 includes an intake manifold 73 on one side parallel to the crank axis a and an exhaust manifold 71 on the other side. In the embodiment, the intake manifold 73 is disposed on the left side surface of the cylinder head 72, and the exhaust manifold 71 is disposed on the right side surface of the cylinder head 72. The cylinder head 72 is mounted on an engine block 75 in which a crankshaft 74 and a piston (not shown) are built. The front and rear front ends of the crankshaft 74 are projected from both front and rear sides of the engine block 75. A cooling fan 76 is provided on one side of the diesel engine 70 that intersects the crank axis a. In the embodiment, the cooling fan 76 is located on the rear side of the engine block 75. The rotational force is transmitted from the rear end side of the crankshaft 74 to the cooling fan 76 via the V belt 77.

  As shown in FIGS. 1 to 3, a flywheel housing 78 is fixed to the other side portion (in the embodiment, the front side surface of the engine block 75) intersecting the crank axis a in the diesel engine 70. A flywheel 79 is disposed in the flywheel housing 78. The flywheel 79 is pivotally supported on the front end side of the crankshaft 74 and is configured to rotate integrally with the crankshaft 74. It is configured such that the power of the diesel engine 70 is taken out via a flywheel 79 to an operation part of a work machine (for example, a hydraulic excavator or a forklift).

  An oil pan 81 is disposed on the lower surface of the engine block 75. Engine leg mounting portions 82 are respectively provided on the left and right side surfaces of the engine block 75 and the left and right side surfaces of the flywheel housing 78. Each engine leg mounting portion 82 is bolted to an engine leg 83 having vibration-proof rubber. The diesel engine 70 is supported in an anti-vibration manner by an engine support chassis 84 such as a work machine (for example, a hydraulic excavator or a forklift) via the engine legs 83.

  The inlet side of the intake manifold 73 is connected to an air cleaner (not shown) via a collector 92 of an EGR device 91 (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, is sent to the intake manifold 73 through the collector 92, and is supplied to each cylinder of the diesel engine 70.

  The EGR device 91 mixes the recirculated exhaust gas (EGR gas from the exhaust manifold 71) of the diesel engine 70 and fresh air (external air from the air cleaner) and supplies it to the intake manifold 73 as a collector line ( An EGR main body case) 92, an intake throttle member 93 that allows the collector 92 to communicate with the air cleaner, a recirculation exhaust gas pipe 95 as a recirculation pipe connected to the exhaust manifold 71 via an EGR cooler 94, and a recirculation exhaust gas pipe 95 has an EGR valve member 96 for communicating the collector 92.

  That is, the intake manifold 73 and the intake air intake throttle member 93 for introducing fresh air are connected in communication via the collector 92. An EGR valve member 96 connected to the outlet side of the recirculation exhaust gas pipe 95 is connected to the collector 92 in communication. The collector 92 is formed in a substantially cylindrical shape with a longitudinal longitudinal direction, and an intake throttle member 93 is bolted to the intake intake side (longitudinal front side) of the collector 92. The supply / discharge side of the collector 92 is bolted to the inlet side of the intake manifold 73. The EGR valve member 96 adjusts the supply amount of EGR gas to the collector 92 by adjusting the opening degree of the EGR valve 97 (see FIG. 15) in the EGR valve member 96.

  Fresh air is supplied into the collector 92, and EGR gas (a part of the exhaust gas discharged from the exhaust manifold 71) is supplied into the collector 92 from the exhaust manifold 71 through the EGR valve member 96. After the fresh air and the EGR gas from the exhaust manifold 71 are mixed in the collector 92, the mixed gas in the collector 92 is supplied to the intake manifold 73. That is, a part of the exhaust gas discharged from the diesel engine 70 to the exhaust manifold 71 is recirculated from the intake manifold 73 to the diesel engine 70, so that the maximum combustion temperature during high load operation decreases, The amount of NOx (nitrogen oxide) emissions is reduced.

  As is apparent from the above configuration, the collector 92 is provided as a relay line for communicating the intake manifold 73 and the intake air intake throttle member 93 for introducing fresh air, and the outlet side of the return line extending from the exhaust manifold 71 is EGR. Since the collector 92 is connected to the collector 92 via the valve member 96, the fresh air and the EGR gas are mixed before being sent to the intake manifold 73. For this reason, the EGR gas can be widely dispersed in the mixed gas, and the variation (unevenness) in the gas mixed state is reduced before the gas is fed into the intake manifold 73. As a result, the mixed gas with little unevenness can be distributed to each cylinder of the diesel engine 70, and variations in the amount of EGR gas between the cylinders can be suppressed. As a result, it is possible to reduce the amount of NOx while suppressing the generation of black smoke and maintaining a good combustion state of the diesel engine 70.

  As shown in FIGS. 1 and 3, a turbocharger 100 is disposed on the right side of the cylinder head 72 and above the exhaust manifold 71. The turbocharger 100 includes a turbine case 101 having a turbine wheel (not shown) and a compressor case 102 having a blower wheel (not shown). An outlet side of the exhaust manifold 71 is connected to the exhaust gas intake pipe 105 of the turbine case 101. A tail pipe (not shown) is connected to the exhaust gas exhaust pipe 103 of the turbine case 101 via a diesel particulate filter 1 (hereinafter referred to as DPF) as an exhaust gas purification device. Exhaust gas discharged from each cylinder of the diesel engine 70 to the exhaust manifold 71 is discharged to the outside through the turbocharger 100, the DPF 1 and the like.

  On the other hand, the supply / discharge side of the air cleaner is connected to the supply / intake side of the compressor case 102 via the supply pipe 104. An intake air intake side of an intake throttle member 93 is connected to an intake air discharge side of the compressor case 102 via a supercharge pipe 108. The fresh air (external air) removed by the air cleaner is sent from the compressor case 102 to the intake manifold 73 via the intake throttle member 93 and the collector 92 and supplied to each cylinder of the diesel engine 70.

  The DPF 1 as an exhaust gas purification device is for collecting particulate matter (PM) and the like in the exhaust gas. As shown in FIGS. 1 to 4, the left and right intersecting the crankshaft 74 in a plan view. It is a substantially cylindrical shape that extends long in the direction, and is disposed on the flywheel housing 78 so as to face the front side surface of the cylinder head 72. On the left and right sides of the DPF 1 (one longitudinal side and the other longitudinal side), an exhaust gas intake side and an exhaust gas discharge side are provided separately from each other. The exhaust gas intake side of the DPF 1 is connected to the exhaust gas discharge pipe 103 of the turbine case 101. The exhaust gas discharge side of the DPF 1 is connected to the exhaust gas intake side of the tail pipe 107.

  The DPF 1 has a structure in which a diesel oxidation catalyst 2 such as platinum and a soot filter 3 having a honeycomb structure are accommodated in series in a substantially cylindrical inner case 4 or 20 built in a DPF casing 60 made of a heat-resistant metal material. (See FIG. 6). As shown in FIGS. 1-4, DPF1 of embodiment is attached to the flywheel housing 78 via the left-right paired bracket legs 61 and 62 as a support body. In this case, one end side of the left bracket leg 61 is bolted to a flange provided on the outer peripheral side of the DPF casing 60. One end side of the right bracket leg 62 is welded and fixed to the outer peripheral side of the DPF casing 60. The other end sides of the left and right bracket legs 61 and 62 are bolted to a DPF attachment portion 80 formed on the upper surface of the flywheel housing 78. That is, the DPF 1 described above is stably connected and supported on the upper portion of the flywheel housing 78 that is a highly rigid member by the left and right bracket legs 61 and 62 and the exhaust gas discharge pipe 103 of the turbine case 101.

  As shown in FIGS. 1 to 4, the DPF casing 60 is provided with an inlet side sensing body 64 and an outlet side sensing body 65 of a differential pressure sensor 63 that detects an internal clogging state. The differential pressure sensor 63 is for detecting a pressure difference between the upstream side and the downstream side across the soot filter 3 in the DPF 1. Based on the pressure difference, the particulate matter accumulation amount of the soot filter 3 is converted, and the clogged state in the DPF 1 can be grasped. Based on the pressure difference detected by the differential pressure sensor 63, for example, the regeneration control of the soot filter 3 is executed by operating the intake throttle member 93. In the embodiment, the detection main body 67 is attached to the sensor bracket 66 fixed to the front side surface of the cylinder head 72. Both sensing bodies 64 and 65 on the DPF casing 60 side are connected to a detection main body 67 of a differential pressure sensor 63 via harnesses 68 and 69, respectively.

  In the above configuration, the exhaust gas of the diesel engine 70 flows from the exhaust gas discharge pipe 103 of the turbine case 101 into the space upstream of the diesel oxidation catalyst 2 in the DPF casing 60, and from the diesel oxidation catalyst 2 to the soot filter 3. In this order, it is purified. Particulate matter in the exhaust gas is collected at this stage without passing through the porous partition walls between the cells in the soot filter 3. Thereafter, exhaust gas that has passed through the diesel oxidation catalyst 2 and the soot filter 3 is discharged to the tail pipe 107.

When the exhaust gas passes through the diesel oxidation catalyst 2 and the soot filter 3, if the exhaust gas temperature exceeds a renewable temperature (for example, about 300 ° C.), the action of the diesel oxidation catalyst 2 causes NO ( Nitric oxide) oxidizes to unstable NO ₂ (nitrogen dioxide). The particulate matter collected by the soot filter 3 is recovered by oxidation removal of the particulate matter deposited on the soot filter 3 with O (oxygen) released when NO ₂ returns to NO ( The soot filter 3 is regenerated).

(2). Next, the fuel system structure of the common rail system 117 and the diesel engine 70 will be described with reference to FIGS. 2, 7, and 8. In FIG. 8, for convenience of explanation, illustration of the EGR device 91 such as the collector 92 and the EGR valve member 96 attached to the intake manifold 73 is omitted. As shown in FIGS. 2, 7, and 8, a fuel tank 118 is connected to each of the four cylinders 115 provided in the diesel engine 70 via a fuel pump 116 and a common rail system 117. Each injector 115 has an electromagnetic switching control type fuel injection valve 119. The common rail system 117 has a cylindrical common rail 120 (pressure accumulation chamber).

  As shown in FIGS. 2, 7, and 8, a fuel tank 118 is connected to the suction side of the fuel pump 116 via a fuel filter 121 and a low pressure pipe 122. The fuel in the fuel tank 118 is sucked into the fuel pump 116 via the fuel filter 121 and the low pressure pipe 122. On the other hand, the common rail 120 is connected to the discharge side of the fuel pump 116 via a high-pressure pipe 123. A high pressure pipe connector 124 is provided in the middle of the longitudinal direction of the cylindrical common rail 120. An end portion of the high-pressure pipe 123 is connected to the high-pressure pipe connector 124 by screwing a high-pressure pipe connector nut 125. In addition, injectors 115 for four cylinders are connected to the common rail 120 via four fuel injection pipes 126, respectively. Fuel injection pipe connectors 127 for four cylinders are provided in the longitudinal direction of the cylindrical common rail 120. An end of the fuel injection pipe 126 is connected to the fuel injection pipe connector 127 by screwing a fuel injection pipe connector nut 128.

  With the above configuration, the fuel in the fuel tank 118 is pumped to the common rail 120 by the fuel pump 116, and high-pressure fuel is stored in the common rail 120. Each fuel injection valve 119 is controlled to open and close, whereby high-pressure fuel in the common rail 120 is injected from each injector 115 to each cylinder of the diesel engine 70. That is, by electronically controlling each fuel injection valve 119, the injection pressure, injection timing, and injection period (injection amount) of the fuel supplied from each injector 115 are controlled with high accuracy. Therefore, nitrogen oxides (NOx) discharged from the diesel engine 70 can be reduced, and noise vibration of the diesel engine 70 can be reduced.

  As shown in FIG. 7, a fuel pump 116 is connected to the fuel tank 118 via a pump fuel return pipe 129. A common rail fuel return pipe 131 is connected to the end of the cylindrical common rail 120 in the longitudinal direction via a return pipe connector 130 with a pressure adjustment valve that limits the pressure of fuel in the common rail 120. The surplus fuel in the fuel pump 116 and the surplus fuel in the common rail 120 are collected in the fuel tank 118 via the pump fuel return pipe 129 and the common rail fuel return pipe 131.

(3). Details of Intake System Structure of Diesel Engine Next, details of the intake system structure of the diesel engine 70 will be described with reference mainly to FIGS. An intake port (not shown) directed to each cylinder of the diesel engine 70 is opened at one side portion (in the embodiment, the left side surface of the cylinder head 72) parallel to the crank axis a in the diesel engine 70. An intake manifold 73 for distributing a mixed gas of fresh air and EGR gas is attached to the intake port (see FIGS. 8 to 10).

  The intake manifold 73 is formed in a longitudinal box shape that opens inward in the lateral direction. In the embodiment, the intake manifold 73 is formed by fastening a head side flange 142 integrally formed around the laterally inward head side opening 141 to the left side surface of the cylinder head 72 with a plurality of bolts 143. A flange is joined to the left side surface of the cylinder head 72 in a state of covering and communicating with the intake port group. Although not shown, a soft material sealing member surrounding the head side opening 141 is interposed between the head side flange 142 and the left side surface of the cylinder head 72. On the rear side near the cooling fan 76 on the lateral outer side surface (left side surface) of the intake manifold 73, an air supply intake side opening portion 144 which is an inlet side is formed. An intake side flange 145 is integrally formed around the intake intake side opening 144.

  As shown in FIGS. 8 and 9, a pair of front and rear fastening bases 133 are integrally formed on the lower surface side of the intake manifold 73. The common rail 120 is integrally formed with a fastening boss portion 134 that protrudes upward and corresponds to the fastening base portion 133 of the intake manifold 73. By fastening the fastening boss part 134 to the fastening base part 133 with the rail mounting bolt 135 from the laterally outer side (left side), the common rail 120 can be attached to and detached from the intake manifold 73 in a posture extending along the intake manifold 73. Suspended and fixed. In the embodiment, the common rail 120 is brought close to the corner of the intake manifold 73 that is diagonally below and to the left. In addition, the common rail 120 is tilted (laid down) about the longitudinal axis so that the high-pressure pipe connector 124 and the fuel injection pipe connector 127 provided on the common rail 120 are laterally outward (leftward outward). .

  On the other hand, the collector 92 serving as a relay pipe constituting the EGR device 91 is located on the laterally outer side (left side in the embodiment) of the intake manifold 73. As described above, the collector 92 is formed in a substantially cylindrical shape having a longitudinal direction and is attached to the lateral outer side surface (left side surface) of the intake manifold 73 so as to extend along the longitudinal direction (front-rear direction) of the intake manifold 73. ing. Therefore, the intake manifold 73 and the collector 92 are set in a side-by-side arrangement relationship.

  An air supply / discharge side opening 146 is formed on the rear inner side (right side) of the collector 92 near the cooling fan 76. A collector-side flange 147 is integrally formed around the air supply / discharge-side opening 146. By superposing the collector side flange 147 on the intake side flange 145 of the intake manifold 73 and fastening with a plurality of bolts 148, the intake manifold 73 and the collector 92 are connected to the intake intake side opening 144 and the supply air discharge side. The flange is joined in a state where the opening 146 is in communication. As described above, the intake throttle member 93 is bolted to the front side in the longitudinal direction, which is the supply air intake side of the collector 92.

  Therefore, as shown in FIG. 11, the inside of the intake manifold 73 and the collector 92 is folded back in a U-turn shape from the intake throttle member 93 to the intake ports through the communicating portions of both openings 144 and 146. It is an intake passage. Further, the communication portion between the intake manifold 73 and the collector 92 (which is also the communication portion between both openings 144 and 146) is located on the rear side near the cooling fan 76. Although not shown in the drawing, a soft material sealing member surrounding the intake intake side opening 144 and the supply air discharge side opening 146 is interposed between the intake side flange 145 and the collector side flange 147. It is inserted.

  As shown in FIGS. 10 and 11, the portion of the collector 92 near the communicating portion has a length in the direction (horizontal direction in the embodiment) that intersects the crank axis a as it approaches the intake manifold 73 in plan view. A shortened inclined portion 150 is formed. In other words, the portion of the collector 92 near the communicating portion is an inclined portion 150 having a shape in which a corner is cut off obliquely in plan view. As shown in FIG. 11, the inclined inner surface 151 of the inclined portion 150 is in a state of covering the passage on the supply air intake side of the collector 92, and one inner surface (left side) of the fresh air flowing from the intake throttle member 93. What flows along the inner side surface is configured to drift in the direction of the center (center side) on the inclined inner surface 151. A reflux opening 152 that opens upward is formed on the upper surface of the collector 92 on the upstream side of the inclined portion 150. A valve flange 153 is integrally formed around the reflux opening 152. The EGR gas discharge side of the EGR valve member 96 is bolted on the valve flange 153.

  In the above configuration, fresh air that has flowed into the collector 92 from the intake throttle member 93 flows toward the cooling fan 76 (rear side). The fresh air flowing along one inner surface (the left inner surface) collides with the inclined inner surface 151 of the inclined portion 150 and drifts toward the center near the lower portion of the reflux opening 152. Therefore, in the vicinity below the reflux opening 152, the flow of fresh air is disturbed as if it forms a counterclockwise vortex as shown in FIG. In contrast to the turbulent flow of fresh air, the EGR gas from the recirculation exhaust gas pipe 95 flows from above through the EGR valve member 96, so that the EGR gas flows simultaneously into the collector 92. Smoothly mixed with fresh air flowing inside. Accordingly, in the collector 92, fresh air and EGR gas can be efficiently mixed while being stirred before being sent to the intake manifold 73 (the EGR gas can be smoothly dispersed in the mixed gas), and the gas mixing state in the collector 92 Variation (unevenness) can be more reliably suppressed.

  The mixed gas mixed in the vicinity of the lower part of the reflux opening 152 is guided to the supply air discharge side opening 146 (communication part) along the inclined inner surface 151 of the inclined part 150, and the flywheel is supplied from the supply air intake side opening 144. The direction is changed to the housing 78 side (front side), flows in the intake manifold 73, and is distributed to each cylinder of the diesel engine 70. As described above, the flow direction of the mixed gas inside the intake manifold 73 is one direction from the supply air intake side opening 144 toward the flywheel housing 78, so that the mixed gas with less unevenness is distributed to each cylinder of the diesel engine 70. Thus, variation in the amount of EGR gas between the cylinders can be significantly reduced. As a result, the generation of black smoke is suppressed, and the NOx amount can be reduced while maintaining the combustion state of the diesel engine 70 in good condition. That is, the exhaust gas can be purified (cleaned) by the recirculation of the EGR gas without causing misfire in a specific cylinder.

  As apparent from the above description and FIGS. 1, 2, 9 and 10, the intake manifold 73 is provided on one side parallel to the crank axis a and the exhaust manifold 71 is provided on the other side. The engine 70 includes an EGR device 91 that recirculates a part of exhaust gas discharged from the exhaust manifold 71 to the intake manifold 73 as EGR gas, and includes the intake manifold 73 and an intake throttle member 93 for introducing fresh air. And the outlet side of the reflux line 95 extending from the exhaust manifold 71 is connected to the relay line 92, and the relay line 92 is connected to the intake manifold 73. Since it is attached to the lateral outer side so as to extend along the intake manifold 73, fresh air and EGR gas are supplied to the intake air. Mixed prior to feeding to the in manifold 73 can reduce variations in gas mixed state (uneven). In addition, the relay pipe line 92 is positioned laterally outward of the intake manifold 73, so that the overall height of the engine 70 can be suppressed low, which contributes to making the engine 70 compact.

  Further, since the relay pipe 92 is attached to the lateral outer side of the intake manifold 73 so as to extend along the intake manifold 73, the length of the relay pipe 92 is set to the length of the intake manifold 73. Since it can be made longer along the direction, the mixing space of fresh air and EGR gas is expanded, contributing to the promotion of mixing of fresh air and EGR gas (EGR gas can be diffused more efficiently in the mixed gas). ).

  As apparent from the above description and FIGS. 1, 2, 9 and 10, a cooling fan 76 is provided on one side crossing the crank axis a, and the intake manifold 73 and the relay conduit 92 are provided. Since the communication portions 144 and 146 are formed close to the cooling fan 76, the flow direction of the mixed gas inside the intake manifold 73 is one direction. Therefore, the mixed gas with little unevenness can be distributed to each cylinder of the engine 70, and the variation in the amount of EGR gas between the cylinders can be greatly reduced. Further, since the cooling air from the cooling fan 76 hits the communication portions 144, 146 between the intake manifold 73 and the relay pipe line 92, it is effective for cooling the mixed gas with less unevenness. As a result, the generation of black smoke is suppressed, and the NOx amount can be reliably reduced while maintaining the combustion state of the engine 70 in good condition. In other words, there is an effect that the exhaust gas can be purified (cleaned) by the recirculation of the EGR gas without causing misfire in a specific cylinder.

  As is apparent from the above description and FIGS. 9 to 11, the portion near the communication portion in the relay pipe 92 is a direction intersecting the crank axis a as it approaches the intake manifold 73 in plan view. Is formed, and the outlet side of the reflux conduit 95 is connected to the upstream side of the inclined portion 150 in the relay conduit 92, so that the relay conduit 92 is connected. Of the fresh air that has flowed into the air, one that flows along one inner surface (the left inner surface) collides with the inner surface side of the inclined portion 150, and is near the outlet side of the reflux conduit 95 in the relay conduit 92. It drifts in the direction of the center. For this reason, in the vicinity of the outlet side of the return conduit 95 in the relay conduit 92, the flow of fresh air is disturbed as if it forms a vortex. Since the EGR gas from the reflux pipe 95 flows into the relay pipe 92 with respect to the turbulent flow of fresh air, the EGR gas flows into the relay pipe 92 at the same time. Smoothly mixed with fresh air flowing inside. Therefore, in the relay pipe 92, fresh air and EGR gas can be efficiently mixed while being stirred before being sent to the intake manifold 73 (EGR gas can be smoothly dispersed in the mixed gas). There is an effect that the variation (unevenness) in the gas mixture state in 92 can be more reliably suppressed.

(4). Connection Structure Between Recirculation Exhaust Gas Pipe and EGR Valve Member Next, a connection structure between the recirculation exhaust gas pipe 95 and the EGR valve member 96 will be described mainly with reference to FIGS. As shown in FIGS. 1, 2, 12, and 13, an EGR valve member 96 for adjusting the supply amount of EGR gas to the intake manifold 73 is disposed above the intake manifold 73. In the embodiment, the EGR valve member 96 extends along the longitudinal direction of the intake manifold 73 (front-rear direction parallel to the crank axis a) on the collector 92 located on the laterally outer side (left side in the embodiment) of the intake manifold 73. Placed in a different posture. The EGR gas discharge side of the EGR valve member 96 having a downward opening is bolted to the valve flange 153 of the collector 92.

  On the other hand, from the portion of the upper surface of the cylinder head 72 near the intake manifold 73, the upper side of the injector 115 for four cylinders protrudes upward in a state of being aligned in the front-rear direction parallel to the crank axis a. A head cover 160 is attached to a portion of the upper surface of the cylinder head 72 near the exhaust manifold 71. Accordingly, the upper side of each injector 115 is not covered by the head cover 160 and is exposed on the cylinder head 72. Further, the EGR valve member 96 and the head cover 160 are in a state that is one step higher than the upper surfaces of the cylinder head 72 and the intake manifold 73 as viewed from the side of the cooling fan 76, for example. Therefore, the upper part of the diesel engine 70 (between the EGR valve member 96 and the head cover 160) is recessed upward, and the recessed space (a recessed space extending back and forth between the EGR valve member 96 and the head cover 160) A ventilation path 161 through which cooling air from the cooling fan 76 toward the flywheel housing 78 passes.

  As shown in FIGS. 12 and 14, the EGR gas of the EGR valve member 96 is arranged so that the outlet side of the recirculation exhaust gas pipe 95 as a reflux pipe extending from the exhaust manifold 71 is positioned closer to the ventilation path 161 in a plan view. Offset to the intake side. The outlet side of the recirculation exhaust gas pipe 95 and the EGR gas intake side of the EGR valve member 96 are connected via an intermediate joint 162. As shown in FIG. 15, an EGR valve 97 for opening and closing the opening is provided at the opening on the EGR gas intake side of the EGR valve member 96.

  As shown in FIGS. 12, 14, and 15, the intermediate joint 162 is formed in a cylindrical shape having an inverted S shape in plan view. The diameter Dg of the gas pipe side opening 163 in the intermediate joint 162 is set smaller than the diameter Db of the valve side opening 164. The center line Cg of the gas pipe side opening 163 is offset upward by an appropriate dimension with respect to the center line Cb of the valve side opening 164. The intermediate communication portion 165 between the gas pipe side opening 163 and the valve side opening 164 in the intermediate joint 162 has a gas pipe side opening due to the relationship between the diameters Dg and Db of the openings 163 and 164 and the offset position. A step 166 is formed that steps downward from 163 toward the valve side opening 164. A protruding portion 167 that protrudes inward so as to cover above the step 166 is formed inside the intermediate communication portion 165 of the intermediate joint 162 facing the step 166. In the vicinity of the valve side opening 164 of the intermediate joint 162, EGR gas flowing down from the gas pipe side opening 163 through the step 166 is caused to flow through the valve side opening 164 due to the presence of the protruding portion 167 that protrudes inward. It is configured to swirl around the center line Cb to form a vortex.

  In the above configuration, the EGR gas that has flowed into the gas pipe side opening 163 of the intermediate joint 162 from the exhaust manifold 71 through the recirculation exhaust gas pipe 95 is the curved inner surface upstream of the step 166 in the intermediate communication part 165. It collides with 168 and flows down to the step 166 side. At this time, because the outlet side of the recirculated exhaust gas pipe 95 is offset and located closer to the ventilation path 161 in a plan view, the periphery (outer peripheral portion) of the curved inner surface 168 of the intermediate joint 162 is more than the EGR valve member 96. It protrudes closer to the ventilation path 161 and is hit by cooling air from the cooling fan 76. For this reason, the temperature rise of the intermediate joint 162 due to the cooling air can be suppressed, and the EGR gas temperature inside thereof can be lowered. As a result, it contributes to cooling of the mixed gas, and there is an effect that it becomes easy to maintain the NOx amount reduction effect by the mixed gas in an appropriate state.

  The EGR gas flowing down from the gas pipe side opening 163 through the step 166 swirls around the center line Cb in the vicinity of the valve side opening 164 in the presence of the inwardly protruding raised portion 167 and generates a vortex. While forming, the EGR valve member 96 is fed to the EGR gas intake side. Then, when the EGR valve 97 is opened, the vortex EGR gas smoothly flows into the gap between the EGR valve 97 and the opening on the EGR gas intake side without being blocked by the EGR valve 97. Therefore, the effect of facilitating the mixing of EGR gas and fresh air via the EGR valve member 96 can be achieved. Such a configuration is particularly useful when fresh air is compressed and supplied to the intake manifold 73 using the turbocharger 100 as in the embodiment. The pressure of the compressed air in the intake manifold 73 and the collector 92 contributes to the direction in which the EGR gas does not easily flow into the EGR valve member 96, but in a direction to cancel the difficulty in flowing by making the EGR gas vortex. Because you can contribute.

  In the embodiment, since the diameter Dg of the gas pipe side opening 163 in the intermediate joint 162 is set smaller than the diameter Db of the valve side opening 164, the gas pipe side opening 163 reaches the valve side opening 164. The cross-sectional area of the path can be enlarged at the intermediate communication portion 165. Accordingly, there is an advantage that an increase in the flow resistance of the EGR gas from the gas pipe side opening 163 to the valve side opening 164 can be avoided.

  As shown in FIGS. 2, 9, and 12, the intermediate joint 162 flows into the intermediate joint 162 on the upstream side of the raised portion 167 (in the embodiment, the outer surface side near the gas pipe side opening 163). An EGR gas temperature sensor 171 for detecting the temperature of the EGR gas is attached. Further, a fresh air temperature sensor 172 for detecting the fresh air temperature is attached to a portion of the collector 92 near the intake throttle member 93. A gas mixture temperature sensor 173 for detecting the temperature of the gas mixture is attached to the inclined portion 150 of the collector 92. The temperature sensors 171 to 173 are used to determine the EGR rate of the mixed gas. Here, the EGR rate means a value obtained by dividing the EGR gas amount by the sum of the EGR gas amount and the fresh air amount (= EGR gas amount / (EGR gas amount + new air amount)).

  In this case, even if there is no means (sensor) for detecting the flow rate and flow velocity of each gas, the EGR rate can be calculated easily and accurately using the fresh air temperature, the EGR gas temperature, and the mixed gas temperature. Further, by adopting a configuration in which the EGR valve member 96 is feedback-controlled based on these calculation results, it is possible to detect the flow rate and flow velocity of each gas without constructing a complicated control system for obtaining the EGR rate. An appropriate amount of EGR gas can be supplied to 92.

  Further, since the EGR gas temperature sensor 171 is attached to the upstream side of the raised portion 167 in the intermediate joint 162, the EGR gas temperature sensor 171 is positioned at a location where the flow velocity is relatively high before flowing into the EGR valve member 96. Will do. For this reason, there exists an effect that the stain | pollution | contamination and performance degradation of the EGR gas temperature sensor 171 by EGR gas can be prevented. In addition, since the temperature of the EGR gas is measured at a location where fresh air cannot be mixed, there is also an advantage that an accurate EGR gas temperature can be measured.

  As apparent from the above description and FIGS. 12 to 15, the cylinder head 72 is provided with an intake manifold 73 on one side parallel to the crank axis a and an exhaust manifold 71 on the other side, and the exhaust An engine 70 including an EGR device 91 that recirculates part of exhaust gas discharged from the manifold 71 to the intake manifold 73 as EGR gas, and an EGR valve member 96 disposed above the intake manifold 73; A ventilation passage 161 through which cooling air from the cooling fan 76 passes is provided between the head cover 160 on the cylinder head 72 and the outlet side of the reflux pipe 95 extending from the exhaust manifold 71 is seen in a plan view. The EGR valve member 96 is offset so as to be positioned closer to the ventilation path 161, and the Since the outlet side of the flow line 95 and the EGR gas intake side of the EGR valve member 96 are connected via an intermediate joint 162, the cooling joint is located in a portion of the intermediate joint 162 near the ventilation path 161. Cooling air from the fan 76 is hit. For this reason, the temperature rise of the intermediate joint 162 due to the cooling air can be suppressed, and as a result, the EGR gas temperature inside thereof can be lowered. As a result, it contributes to cooling of the mixed gas, and there is an effect that it becomes easy to maintain the NOx amount reduction effect by the mixed gas in an appropriate state.

  As apparent from the above description and FIGS. 14 and 15, the intermediate joint 162 has an elevated portion for turning EGR gas around the center line Cb on the EGR gas discharge side inside the EGR gas discharge side. Since 167 is formed, the EGR gas flowing from the EGR gas intake side 163 swirls around the center line Cb in the vicinity of the EGR gas discharge side 164 in the presence of the protruding portion 167 projecting inwardly. The EGR valve member 96 is fed into the EGR gas intake side while forming a vortex flow. Then, the eddy current EGR gas is not blocked by the EGR valve 97 when the EGR valve 97 is opened, and is formed in a gap between the EGR gas intake side opening of the EGR valve member 96 and the EGR valve 97. It will flow smoothly. Therefore, the effect of facilitating the mixing of the EGR gas and fresh air via the EGR valve member 96 can be achieved.

  As apparent from the above description and FIGS. 12, 14 and 15, an EGR gas temperature sensor 171 for detecting the temperature of EGR gas is attached to the upstream side of the raised portion 167 in the intermediate joint 162. Therefore, the EGR gas temperature sensor 171 is located at a location where the flow velocity is relatively high before flowing into the EGR valve member 96. For this reason, there is an effect that the EGR gas temperature sensor 171 can be prevented from being contaminated and performance deteriorated by the EGR gas. In addition, since the temperature of the EGR gas is measured at a location where fresh air cannot be mixed, there is also an advantage that an accurate EGR gas temperature can be measured.

(5). Details of Arrangement Structure of Common Rail System Next, details of the arrangement structure of the common rail system 117 will be described with reference to FIGS. 8, 9, 13, and 16 to 19. As shown in FIGS. 8, 9, 13 and 16 to 19, a fuel pump 116 for supplying high pressure fuel to the common rail 120 is provided on the left side surface of the engine block 75 on the intake manifold 73 side. It is arrange | positioned in the state which was brought close to the cooling fan 76 side. The fuel pump 116 pressurizes the fuel via the feed pump 177 for sucking the fuel in the fuel tank 118, the metering valve 178 for adjusting the fuel suction amount by the feed pump 177, and the metering valve 178. And a plunger 179 for supplying to the common rail 120. The feed pump 177 is driven by the rotational drive of the crankshaft 74 and the fuel in the fuel tank 118 is sucked through the fuel filter 121. Further, the rotation of the crankshaft 74 drives the plunger 179 to reciprocate, pressurizes the fuel that has passed through the metering valve 178, and then pumps it to the common rail 120.

  As shown in FIGS. 16 to 19, a feed pump 177 is disposed on the front side surface of the fuel pump 116 near the flywheel housing 78. From the upper side of the fuel pump 116, the upper part of the metering valve 178 and the upper part of the plunger 179 protrude upward. In the embodiment, as viewed from the direction of the crank axis a, the plunger 179 is located on the inner side (right side, engine block 75 side), and the metering valve 178 is located on the outer side (left side). Further, the upper portions of the metering valve 178 and the plunger 179 are arranged in a V shape on the upper side of the fuel pump 116 when viewed from the direction of the crank axis a. Therefore, a V-shaped dead space 180 exists between the upper part of the metering valve 178 and the upper part of the plunger 179.

  As shown in FIGS. 8, 9, and 16 to 19, the common rail 120 is directly attached to the intake manifold 73 so as to be positioned obliquely below the left outside of the intake manifold 73. In the embodiment, a pair of front and rear fastening base portions 133 are integrally formed separately from the head side flange 142 on the lower surface side of the intake manifold 73. On the other hand, the common rail 120 is integrally formed with an upward projecting fastening boss portion 134 corresponding to each fastening base portion 133. By fastening the fastening boss part 134 to the fastening base part 133 with the rail mounting bolt 135 from the laterally outer side (left side), the common rail 120 can be attached to and detached from the intake manifold 73 in a posture extending along the intake manifold 73. Suspended and fixed. In this case, the common rail 120 is close to the corner of the intake manifold 73 that is diagonally below and to the left. Therefore, the common rail 120 faces the one side surface (left side surface) of the engine block 75 with an appropriate space ΔL. In other words, the common rail 120 is arranged away from the one side surface (left side surface) of the engine block 75 by a distance ΔL as appropriate to the outside in the lateral direction.

  Further, as shown in FIGS. 8, 9, and 16 to 19, the common rail 120 is arranged such that the high-pressure pipe connector 124 and the fuel injection pipe connector 127 provided on the common rail 120 face laterally outward (leftward outward). Is tilted around the longitudinal axis (being laid down). The high-pressure pipe connector 124 and the fuel injection pipe connector 127 for four cylinders are provided side by side at the same pitch interval P in the longitudinal direction (front-rear direction). In the embodiment, the high-pressure pipe connector 124 is disposed at the longitudinal center of the common rail 120. Two fuel injection pipe connectors 127 are arranged on both sides of the high-pressure pipe connector 124. One fastening boss part 134 protrudes upward from the position of the fuel injection pipe connector 127 at the foremost end (end part on the return pipe connector 130 side) of the common rail 120. The other fastening boss part 134 protrudes upward from the position of the fuel injection pipe connector 127 at the rearmost end.

  As described above, the common rail 120 is detachably suspended from the intake manifold 73 in a posture extending along the intake manifold 73. In addition, when viewed from the direction of the crank axis a, the fuel is such that one end (rear end) in the longitudinal direction of the common rail 120 is positioned between the metering valve 178 on the fuel pump 116 and the plunger 179. An arrangement relationship between the pump 116 and the common rail 120 is set (see FIGS. 13 and 17). That is, when viewed from the direction of the crank axis a, one end portion (rear end portion) of the common rail 120 in the longitudinal direction is positioned in the dead space 180 between the upper portion of the metering valve 178 and the upper portion of the plunger 179. (The rear end of the common rail 120 faces the dead space 180).

  By the way, the collector 92 which comprises the EGR apparatus 91 is attached to the horizontal outer side surface (left side surface) of the intake manifold 73 so that it may extend along the longitudinal direction (front-back direction) of the intake manifold 73 (as mentioned above). FIG. 8 to FIG. 10). On the other hand, the common rail 120 is located obliquely below the left outer side of the intake manifold 73 and projects each fuel injection pipe connector 127 outward in the lateral direction (left outer side). The fuel inlet side of the corresponding fuel injection pipe 126 is connected to each fuel injection pipe connector 127 facing outward in the lateral direction by screwing a fuel injection pipe connector nut 128. The fuel outlet side of each fuel injection pipe 126 is connected to the corresponding injector 115. Each fuel injection pipe 126 is curved along the outer shape of the collector 92 or the intake manifold 73.

  Here, in the description of FIG. 16, the first fuel injection pipe, the second fuel injection pipe,... In the rearward order from the fuel injection pipe 126 positioned on the flywheel housing 78 side (front side) of the diesel engine 70. The alphabet corresponding to the arrangement order is attached to each code (for example, the code of the first fuel injection pipe is 126a, the code of the second fuel injection pipe is 126b, etc.).

  As shown in FIG. 16, the first and second fuel injection pipes 126 a and 126 b are curved along the outer shape of the intake manifold 73. In this case, the intermediate portions of the first and second fuel injection pipes 126a and 126b are passed through the gap between the intake manifold 73 and the intake throttle member 93. Portions of the first and second fuel injection pipes 126 a and 126 b positioned on the intake manifold 73 are bolted together to the upper surface of the intake manifold 73 through a metal clamp 181. The third and fourth fuel injection pipes 126c and 126d are curved along the outer shape of the collector 92 (near the inclined portion 150). Portions of the third and fourth fuel injection pipes 126c and 126d located on the intake manifold 73 are also bolted to the upper surface of the intake manifold 73 through a metal clamp 181. All these fuel injection pipes 126 are made equal in length by being curved along the outer shape of the collector 92 or the intake manifold 73.

  As is clear from the above description and FIGS. 16 to 19, the common rail 120 is disposed on one side of the engine block 75 so as to be close to the intake manifold 73. The intake manifold 73 is directly attached to the intake manifold 73 so as to be located obliquely below the intake manifold 73 and is opposed to one side of the engine block 75 at an appropriate interval. The common rail 120 can be firmly supported at the same time, and the common rail 120 is separated from one side of the engine block 75, so that the influence of the combustion heat of the engine 70 on the common rail 120 can be suppressed, and overheating can occur. Damage to the common rail 120 can be prevented in advance. The effect say.

  As is apparent from the above description and FIGS. 16 to 19, the common rail 120 extends along the longitudinal direction of the intake manifold 73 and the fuel injection pipe connector 126 provided on the common rail 73 faces outward in the lateral direction. Since it is suspended and fixed to the intake manifold 73 by bolts 135 from the outside in the lateral direction, the mounting / removing operation of the common rail 120 to the intake manifold 73 (bolt 135 fastening / unfastening operation) can be easily performed. Can be executed. Also, a nut screwing operation for connecting the fuel injection pipe 126 to the fuel injection pipe connector 127 can be easily performed. That is, it is possible to improve the workability of attaching / detaching the common rail 120 and its piping.

  As shown in the above description and FIGS. 16 to 19, a fuel pump 116 that supplies high-pressure fuel to the common rail 120 is disposed below the intake manifold 73, as viewed from the direction of the crank axis a. The arrangement relationship between the fuel pump 116 and the common rail 120 is set so that one end of the common rail 120 is positioned between the metering valve 178 and the plunger 179 that protrude upward from the upper portion of the fuel pump 116. The fuel pump 116 and the common rail 120 can be arranged as close as possible by using a dead space 180 formed between the upper portion of the metering valve 178 and the upper portion of the plunger 179. . For this reason, the arrangement relationship (arrangement relationship of the common rail system) of the fuel pump 116, the common rail 120, and the intake manifold 73 can be made compact, and there is an effect that the restriction of the engine to be mounted can be reduced. For example, the common rail 120 can be mounted on a small engine.

  As is apparent from the above description and FIGS. 16 to 19, an EGR device 91 that recirculates a part of the exhaust gas discharged from the exhaust manifold 71 to the intake manifold 73 as EGR gas, and an intake throttle that adjusts the intake air amount A relay conduit 92 that communicates the member 93 and the intake manifold 73 is provided, and the relay conduit 92 is attached to the laterally outer side portion of the intake manifold 73 so as to extend along the intake manifold 73. In addition, since the fuel injection pipe 126 connecting the common rail 120 and each injector 115 is curved along the outer shape of the relay pipe 92 or the intake manifold 73, the bending angle of each fuel injection pipe 126 is changed. It can be formed larger by following the outer shape of the relay pipe 92 or the intake manifold 73.For this reason, the piping resistance of the high-pressure fuel supplied to each injector 115 can be reduced, and the engine 70 performance can be improved.

(6). Arrangement Mode of Common Rail System Between Engines with Different Numbers of Cylinders Next, with reference to FIGS. 16 and 20 to 22, an arrangement mode of a common rail system 117 between a plurality of engines 70 and 70 ′ with different numbers of cylinders. explain. The diesel engine 70 shown in FIG. 16 is of a four cylinder type, whereas the diesel engine 70 ′ shown in FIG. 20 is of a three cylinder type. A conspicuous difference between these diesel engines 70 and 70 'is that the three-cylinder diesel engine 70' has one cylinder in the longitudinal direction of the engine blocks 75 and 75 'and the cylinder heads 72 and 72' in the direction of the crank axis a. It is a point that is shorter by a small amount. Accordingly, the intake manifold 73 ′ of the three-cylinder type diesel engine 70 ′ is also shorter in the longitudinal direction in the direction of the crank axis a than that of the four-cylinder type. In the following description, the configuration of the common rail system 117 is basically common to the case of the four-cylinder type and the case of the three-cylinder type. And

  In the comparison between the 4-cylinder type diesel engine 70 shown in FIG. 16 and the 3-cylinder type diesel engine 70 ′ shown in FIG. 20, the positional relationship of the common rail 120 with respect to the fuel pump 116 is more than the 4-cylinder type. In this case, the connectors 124 and 127 are shifted by the arrangement pitch interval P so that the common rail 120 approaches the fuel pump. Therefore, as shown in FIGS. 20 and 21, in the case of the three-cylinder type, one end portion (rear end portion) of the common rail 120 in the longitudinal direction is dead between the metering valve 178 and the plunger 179 on the fuel pump 116. It enters the space 180. In the case of the three-cylinder type, the frontmost fuel injection pipe connector 127 in the common rail 120 is closed. The second connector from the front is set to the high pressure pipe connector 124. The remaining three fuel injection pipe connectors 127 are connected to the injectors 115 for the three cylinders via the fuel injection pipe 126.

  Here, the third and fourth fuel injection pipes 126c and 126d used in the four-cylinder type are also used in the three-cylinder type. In other words, by shifting the positional relationship of the common rail 120 with respect to the fuel pump 116 by the pitch P of the connectors 124 and 127, at least the plurality of fuel injection pipes 126c and 126d connected to the connectors 124 and 127 are curved. Without being changed, it is a common part among a plurality of diesel engines 70, 70 'having different numbers of cylinders.

  That is, the third fuel injection pipe 126c connects the middle injector 115 in the three-cylinder type and the fuel injection pipe connector 127 at the central portion of the common rail 120 in the longitudinal direction. The fourth fuel injection pipe 126d connects the injector 115 on the cooling fan 76 side in the three-cylinder type and the fourth fuel injection pipe connector 127 from the front in the common rail 120. The high-pressure pipe 123 used in the four-cylinder type is also used in the three-cylinder type as a common part that does not change its curved shape. In this case, the second high pressure pipe connector 124 from the front in the common rail 120 and the fuel pump 116 are connected via the high pressure pipe 123 described above. A fuel injection pipe 126e that connects the injector 115 on the flywheel housing 78 side in the three-cylinder type and the rearmost fuel injection pipe connector 127 in the common rail 120 is a fuel injection pipe having a curved shape dedicated to the three-cylinder type. .

  FIG. 22 shows an example in which the positional relationship of the common rail 120 with respect to the fuel pump 116 is set as in the case of a four-cylinder type in a three-cylinder type diesel engine 70 ′. That is, FIG. 22 shows an example in which the positional relationship of the common rail 120 with respect to the fuel pump 116 is the same as that in the case of the four-cylinder type. In this example, the other end portion (rear end portion) in the longitudinal direction of the common rail 120 protrudes out from the front surface of the engine block 75 on the flywheel side, but the second, third, and third types used in the four-cylinder type are used. The fourth fuel injection pipes 126b, 126c, 126d and the high-pressure pipe 123 are also used as a common part in the three-cylinder type.

  That is, the second fuel injection pipe 126 b connects the injector 115 on the flywheel housing 78 side in the three-cylinder type and the second fuel injection pipe connector 127 from the front in the common rail 120. The third fuel injection pipe 126c connects the middle injector 115 in the three-cylinder type and the fourth fuel injection pipe connector 127 from the front in the common rail 120. The fourth fuel injection pipe 126d connects the injector 115 on the cooling fan 76 side in the three-cylinder type and the rearmost fuel injection pipe connector 127 in the common rail 120. The middle high-pressure pipe connector 124 in the common rail 120 and the fuel pump 116 are connected via the high-pressure pipe 123 described above.

  As is apparent from the above description and FIGS. 16 to 22, the fuel injection system 117 has the common rail 120 disposed on one side of the engine blocks 75 and 75 ′ and in proximity to the intake manifolds 73 and 73 ′. The common rail 120 is provided with connectors 124 and 127 arranged at the same pitch interval P in the longitudinal direction, and between the plurality of engines 70 and 70 'having different numbers of cylinders, below the intake manifolds 73 and 73'. By making the positional relationship of the common rail 120 with respect to the fuel pump 116 at the same position or by shifting the position by the pitch P of the connectors 124, 127, at least a plurality of connectors connected to the connectors 124, 127 The fuel injection pipe 126 can be connected to a plurality of engines having different numbers of cylinders without changing the curved shape. Therefore, it is not necessary to prepare not only the common rail 120 but also various fuel injection pipes 126 having different curved shapes for each model of the engines 70 and 70 '. Can be reduced. Therefore, there is an effect that the cost can be reduced when the fuel injection system 117 is adopted.

  As apparent from the above description and FIGS. 16 to 22, the connectors 124 and 127 of the common rail 120 are connected to the injectors 115 corresponding to the cylinders of the engines 70 and 70 ′ via the fuel injection pipe 126. A plurality of fuel injection pipe connectors 127 and a high-pressure pipe connector 124 connected to the fuel pump 116 via a high-pressure pipe 123. The high-pressure pipe 123 is a cylinder without changing its curved shape. Since the plurality of engines 70 and 70 ′ having different numbers are common parts, the high-pressure pipe 123 is not limited to a dedicated part for each type of the engines 70 and 70 ′, similarly to the fuel injection pipe 126. Thus, it is possible to further reduce the number of parts and thus contribute to further cost reduction.

(7). Next, the structure of the exhaust gas purification apparatus will be described with reference to FIGS. 6 and 23 to 28. As shown in FIGS. 6 and 23 to 27, a continuously regenerating diesel particulate filter 1 (DPF) as an exhaust gas purifying device is provided. The DPF 1 can reduce carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas in addition to removal of particulate matter (PM) in the exhaust gas.

  As shown in FIGS. 6 and 27, the diesel oxidation catalyst 2, which is an example of a filter for purifying exhaust gas discharged from the diesel engine 70, is provided in a substantially cylindrical catalyst inner case 4 made of a heat-resistant metal material. . The catalyst inner case 4 is made of a heat resistant metal material and is provided in a substantially cylindrical catalyst outer case 5. That is, the catalyst inner case 4 is fitted on the outside of the diesel oxidation catalyst 2 via the ceramic heat insulating material 6 made of ceramic fiber. Further, the catalyst outer case 5 is fitted on the outer side of the catalyst inner case 4 via an end plate L-shaped support 7. The catalyst outer case 5 is one of the elements that constitute the DPF casing 60 described above. Note that the diesel oxidation catalyst 2 is protected by the catalyst heat insulating material 6. The stress (deformation force) of the catalyst outer case 5 transmitted to the catalyst inner case 4 is reduced by the thin plate support 7.

  As shown in FIGS. 6 and 27, a disk-shaped side cover 8 is fixed to one end of the catalyst inner case 4 and the catalyst outer case 5 by welding. An outer lid body 9 is fastened to the outer surface side of the side lid body 8 with bolts and nuts. The one end face 2a of the diesel oxidation catalyst 2 and the side lid 8 are opposed to each other with a predetermined distance L1 for gas inflow space. An exhaust gas inflow space 11 is formed between the left end face 2 a of the diesel oxidation catalyst 2 and the left lid 8. An exhaust gas inlet 12 facing the exhaust gas inflow space 11 is opened in the catalyst inner case 4 and the catalyst outer case 5. Although illustration is omitted, a closing ring body is fixed in a sandwiched manner between the opening edge of the catalyst inner case 4 and the opening edge of the catalyst outer case 5. By closing the gap between the opening edge of the catalyst inner case 4 and the opening edge of the catalyst outer case 5 with a closing ring body, the exhaust gas is prevented from flowing between the catalyst inner case 4 and the catalyst outer case 5. doing.

  As shown in FIGS. 6, 23, 24 and 27, an exhaust gas inlet pipe 16 is disposed on the outer surface of the catalyst outer case 5 in which the exhaust gas inlet 12 is formed. One open end of the exhaust gas inlet pipe 16 is flange-joined to the exhaust gas discharge pipe 103 of the turbine case 101 in the turbocharger 100 (see FIGS. 1 and 3). Therefore, the exhaust gas inlet pipe 16 is connected to the exhaust manifold 71 of the diesel engine 70 via the exhaust gas discharge pipe 103 of the turbine case 101. The other open end of the exhaust gas inlet pipe 16 is welded to the outer surface of the catalyst outer case 5 so as to cover the exhaust gas inlet 12 from the outside.

With the above configuration, the exhaust gas of the diesel engine 70 enters the exhaust gas inlet pipe 16 from the exhaust manifold 71, enters the exhaust gas inflow space 11 from the exhaust gas inlet pipe 16 through the exhaust gas inlet 12, and the diesel oxidation catalyst. 2 is supplied from the left end face 2a. Nitrogen dioxide (NO ₂ ) is generated by the oxidation action of the diesel oxidation catalyst 2.

  As shown in FIGS. 6 and 27, the soot filter 3 as an example of a filter is provided in a substantially cylindrical filter inner case 20 made of a heat-resistant metal material. The filter inner case 20 is made of a heat-resistant metal material and is provided in a substantially cylindrical filter outer case 21. That is, the filter inner case 20 is fitted on the outside of the soot filter 3 through the mat-shaped filter heat insulating material 22 made of ceramic fiber. The filter outer case 21 is one of the elements constituting the DPF casing 60 described above together with the catalyst outer case 5. The soot filter 3 is protected by the filter heat insulating material 22.

  As shown in FIGS. 6 and 27, the catalyst inner case 4 is composed of a small diameter cylindrical portion 4a that houses the diesel oxidation catalyst 2 and a large diameter cylindrical portion 4b into which a filter inner case 20 described later is inserted. In this case, the downstream end portion of the small diameter cylindrical portion 4a is fitted into the upstream end portion of the large diameter cylindrical portion 4b, and the overlapping portion of the small diameter cylindrical portion 4a and the large diameter cylindrical portion 4b is fixed by welding. Thus, a catalyst inner case 4 having a part of a double cylinder structure is formed.

  A thin plate-like catalyst side joining flange 25 protruding from the outer peripheral side (radius outside) of the catalyst outer case 5 is welded and fixed to the downstream end of the catalyst inner case 4. The downstream end of the catalyst outer case 5 is welded and fixed to the outer peripheral side of the catalyst side joining flange 25. A thin plate-like filter-side joining flange 26 that protrudes to the outer peripheral side (radius outer side) of the filter outer case 21 is welded and fixed to a longitudinally middle portion of the filter inner case 20. The upstream end of the filter outer case 21 is fixed by welding to the outer peripheral side of the filter side joining flange 26.

  As shown in FIGS. 6 and 23 to 27, the catalyst side joining flange 25 and the filter side joining flange 26 are abutted with each other through the packing 24, and a pair of thick plate-like shapes surrounding the outer peripheral side of each outer case 5, 21. The joint flanges 25 and 26 are clamped from both sides in the exhaust gas movement direction by the center clamping flanges 51 and 52, and both the center clamping flanges 51 and 52 are fastened together by the bolts 27 and the nuts 28. By doing so, the catalyst outer case 5 and the filter outer case 21 are connected. Note that the diameter dimension of the cylindrical small-diameter cylindrical portion 4a in the catalyst inner case 4 and the diameter dimension of the cylindrical filter inner case 20 are substantially the same dimension. Further, the diameter of the cylindrical catalyst outer case 5 and the diameter of the cylindrical filter outer case 21 are substantially the same.

  As shown in FIG. 6, in the state where the filter outer case 21 is connected to the catalyst outer case 5 via both center clamping flanges 51 and 52 and both joint flanges 25 and 26, the downstream end of the catalyst inner case 4 In addition, the upstream end of the filter inner case 20 is opposed to the sensor mounting fixed distance L2. As shown in FIGS. 6 and 25, the cylindrical length L4 of the catalyst outer case 5 in the exhaust gas movement direction is formed longer than the cylindrical length L3 of the small diameter cylindrical portion 4a in the catalyst inner case 4 in the exhaust gas movement direction. ing. The cylindrical length L6 of the filter outer case 21 in the exhaust gas movement direction is shorter than the cylindrical length L5 of the filter inner case 20 in the exhaust gas movement direction. The catalyst outer case 5 has a length (L2 + L3 + L5) obtained by adding the constant interval L2 of the sensor mounting space 29, the cylindrical length L3 of the small-diameter cylindrical portion 4a of the catalyst inner case 4 and the cylindrical length L5 of the filter inner case 20. The length (L4 + L6) obtained by adding the cylindrical length L4 and the cylindrical length L6 of the filter outer case 21 is substantially the same.

  The upstream end of the filter inner case 20 protrudes from the upstream end of the filter outer case 21 by a difference in length (L7 = L5−L6). In other words, in a state where the filter outer case 21 is connected to the catalyst outer case 5, the upstream end of the filter inner case 20 is within the downstream side (large diameter cylindrical portion 4b) of the catalyst outer case 5 by the overlap dimension L7. Will be inserted.

With the above configuration, nitrogen dioxide (NO ₂ ) generated by the oxidation action of the diesel oxidation catalyst 2 is supplied to the soot filter 3 from the one side end face 3a side. Particulate matter (PM) in the exhaust gas of the diesel engine 70 collected by the soot filter 3 is continuously oxidized and removed by nitrogen dioxide (NO ₂ ). In addition to the removal of particulate matter (PM) in the exhaust gas of the diesel engine 70, carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas of the diesel engine 70 are reduced.

  As shown in FIGS. 6, 26, and 27, the silencer 30 that attenuates the exhaust gas sound exhausted from the diesel engine 70 is made of a heat-resistant metal material and is made of a substantially cylindrical muffler inner case 31 and made of a heat-resistant metal material. It has a cylindrical silencer outer case 32 and a disk-like side lid 33 fixed to the downstream side end of the silencer outer case 32 by welding. A silencer inner case 31 is provided in the silencer outer case 32. The silencer outer case 32 is also one of the elements constituting the DPF casing 60 described above together with the catalyst outer case 5 and the filter outer case 21. The cylindrical silencer outer case 32 has substantially the same dimensions as the diameter of the cylindrical catalyst outer case 5 and the diameter of the cylindrical filter outer case 21.

  Disc-shaped inner lid bodies 36 and 37 are fixed to both ends of the muffler inner case 31 in the exhaust gas movement direction by welding. A pair of exhaust gas introduction pipes 38 is provided between the inner lids 36 and 37. The upstream side of these exhaust gas introduction pipes 38 penetrates the upstream inner lid 36. The downstream side of both exhaust gas introduction pipes 38 is closed by a downstream inner lid body 37. A plurality of communication holes 39 are formed on the outer peripheral side of each exhaust gas introduction pipe 38. A space between the inner lids 36 and 37 in the silencer inner case 31 is an expansion chamber 45 communicating with both exhaust gas introduction pipes 38 through a communication hole 39.

  The silencer inner case 31 and the silencer outer case 32 are penetrated by an exhaust gas outlet pipe 34 passing between the two exhaust gas introduction pipes 38. One end side of the exhaust gas outlet pipe 34 is closed by an outlet lid 35. A large number of exhaust holes 46 are formed in the entire exhaust gas outlet pipe 34 inside the silencer inner case 31. Both exhaust gas introduction pipes communicate with the exhaust gas outlet pipe 34 via a plurality of communication holes 39, expansion chambers 45, and a number of exhaust holes 46. A tail pipe and an existing silencing member (both not shown) are connected to the other end side of the exhaust gas outlet pipe 34. With the above configuration, the exhaust gas that has entered the both exhaust gas introduction pipes 38 of the silencer inner case 31 passes through the exhaust gas outlet pipe 34 via the plurality of communication holes 39, the expansion chambers 45, and the numerous exhaust holes 46. Then, it is discharged out of the silencer 30.

  As shown in FIGS. 6 and 27, a thin plate-like filter outlet side joining flange 40 protruding from the outer peripheral side (radially outer side) of the filter outer case 21 is fixed by welding to the downstream end of the filter inner case 20. The downstream end of the filter outer case 21 is fixed to the outer periphery of the filter outlet side joining flange 40 by welding. A thin-plate-like silencer-side joining flange 41 that protrudes from the outer peripheral side (radius outside) of the silencer outer case 32 is welded and fixed to the upstream end of the silencer inner case 31. The upstream end of the silencer outer case 32 is welded and fixed to the outer peripheral side of the silencer side joining flange 41.

  As shown in FIG. 6 and FIGS. 23 to 27, a pair of thick plate shapes that butt the filter outlet side joining flange 40 and the muffler side joining flange 41 through the packing 24 and surround the outer peripheral sides of the outer cases 21 and 32. The both outlet flanges 53 and 54 are clamped from both sides in the exhaust gas movement direction, and both the outlet clamp flanges 53 and 54 are connected to both the joint flanges 40 and 41 by bolts 42 and nuts 43. By fastening, the filter outer case 21 and the muffler outer case 32 are connected.

  As shown in FIGS. 6 and 27, the cylindrical length L9 of the muffler outer case 32 in the exhaust gas movement direction is shorter than the cylinder length L8 of the muffler inner case 31 in the exhaust gas movement direction. The upstream end of the muffler inner case 31 protrudes from the upstream end of the muffler outer case 32 by a difference in length (L10 = L8−L9). In other words, in a state where the silencer outer case 32 is connected to the filter outer case 21, the upstream end of the silencer inner case 31 is downstream of the filter outer case 21 by the overlap dimension L10 (filter outlet side joining flange 40). Will be inserted inside.

  As shown in FIGS. 6 and 23 to 27, the thick plate-like central clamping flange 51 (52) is divided into a plurality (two in the embodiment) in the circumferential direction of the catalyst outer case 5 (filter outer case 21). Unit 51a, 51b (52a, 52b). Each unit 51a, 51b (52a, 52b) of the embodiment is formed in an arc shape (substantially semicircular shape). In a state where the filter outer case 21 is connected to the catalyst outer case 5, the ends of both units 51a, 51b (52a, 52b) abut each other along the circumferential direction, and the catalyst outer case 5 (filter outer case 21) The outer peripheral side is enclosed in an annular shape. The catalyst-side units 51a and 51b and the filter-side units 52a and 52b are all in the same form (same type).

  The central clamping flange 51 (52) is provided with a plurality of bolt fastening portions 55 with through holes at equal intervals along the circumferential direction. In the embodiment, eight bolt fastening portions 55 are provided on one set of central clamping flanges 51. When viewed in units of units 51a and 51b (52a and 52b), four bolt fastening portions 55 are provided at equal intervals along the circumferential direction. On the other hand, bolt holes 56 corresponding to the respective bolt fastening portions 56 of the center clamping flange 51 (52) are formed through the catalyst side joining flange 25 and the filter side joining flange 26.

  When connecting the catalyst outer case 5 and the filter outer case 21, the outer peripheral side of the catalyst outer case 5 is surrounded by both the catalyst side units 51 a and 51 b, and the outer peripheral side of the filter outer case 21 is both the filter side units 52 a. , 52b, and the catalyst side joining flange 25 and the filter side joining flange 26 sandwiching the packing 24 are sandwiched by these unit groups (center clamping flanges 51, 52) from both sides in the exhaust gas movement direction. In this state, the bolts 27 are inserted into the bolt fastening portions 55 of the center clamping flanges 51 and 52 on both sides and the bolt holes 56 of the joint flanges 25 and 26 and tightened with the nuts 28. As a result, the joint flanges 25 and 26 are sandwiched and fixed by the center sandwich flanges 51 and 52, and the connection between the catalyst outer case 5 and the filter outer case 21 is completed. Here, the abutting portions of the end portions of the catalyst-side units 51a and 51b and the filter-side units 52a and 52b are configured so as to be shifted from each other by about 90 °.

  As shown in FIGS. 6 and 23 to 27, the thick plate-like outlet clamping flange 53 (54) is divided into a plurality (two in the embodiment) in the circumferential direction of the filter outer case 21 (silencer outer case 32). Unit 53a, 53b (54a, 54b). Each unit 53a, 53b (54a, 54b) of the embodiment has basically the same form as the unit 51a, 51b (52a, 52b) of the center clamping flange 51 (52). The outlet clamping flange 53 (54) is also provided with a plurality of bolt fastening portions 57 with through holes at equal intervals along the circumferential direction. On the other hand, bolt holes 58 corresponding to the respective bolt fastening portions 57 of the outlet clamping flange 53 (54) are formed through the filter outlet side joining flange 40 and the silencer side joining flange 41.

  When connecting the filter outer case 21 and the silencer outer case 32, the outer periphery side of the filter outer case 21 is surrounded by both units 53a and 53b on the filter outlet side, and the outer periphery side of the silencer outer case 32 is both the silencer side unit. The filter outlet side joining flange 40 and the muffler side joining flange 41 which are enclosed by 54a and 54b and sandwich the packing 24 are sandwiched from both sides in the exhaust gas movement direction by these unit groups (exit sandwiching flanges 53 and 54). In this state, the bolts 42 are inserted into the bolt fastening portions 57 of the outlet clamping flanges 53 and 54 on both sides and the bolt holes 58 of the joint flanges 40 and 41 and tightened with the nuts 43. As a result, both the joining flanges 40 and 41 are sandwiched and fixed by the both outlet sandwiching flanges 53 and 54, and the connection between the filter outer case 21 and the silencer outer case 32 is completed. Here, the abutting portions of the end portions of the filter outlet side units 53a and 53b and the silencer side units 54a and 54b are configured to be positioned with a phase shift of about 90 °.

  As shown in FIGS. 23 to 26 and FIG. 28, the left bracket as a support for supporting the DPF casing 60 (the outer cases 5, 21, 32) on the diesel engine 70 on at least one of the sandwiching flanges 51 to 54. A leg 61 is attached. In the embodiment, in one unit 53a of the outlet holding flange 53 on the filter outlet side, a support body fastening portion 59 with a through hole is integrally formed at two locations so as to be positioned between adjacent bolt fastening portions 57. ing. On the other hand, the left bracket leg 61 is integrally formed with a mounting boss portion 86 corresponding to the support body fastening portion 59 described above. By fastening the mounting boss portion 86 of the left bracket leg 61 to the support fastening portion 59 of one unit 53a on the filter outlet side, the left bracket leg 61 can be attached to and detached from the outlet clamping flange 53 on the filter outlet side. Fixed. One end side of the right bracket leg 62 is welded and fixed to the outer peripheral side of the DPF casing 60 (catalyst outer case 5), and the other end sides of the left and right bracket legs 61 and 62 are DPF formed on the upper surface of the flywheel housing 78. As described above, the bolts are fastened to the attachment portion 80. As a result, the DPF 1 is stably connected and supported on the upper portion of the flywheel housing 78, which is a high-rigidity member, by the left and right bracket legs 61 and 62 and the exhaust gas discharge pipe 103 of the turbine case 101.

  As apparent from the above description and FIGS. 6 and 23 to 28, the filters 2 and 3 for purifying the exhaust gas exhausted by the engine 70, and the inner cases 4, 20 and 31 containing the filters 2 and 3, The exhaust gas purifying apparatus 1 has the outer cases 5, 21, and 32 in which the inner cases 4, 20, and 31 are housed, and the inner cases 4, 20, and 31 are connected to the outer cases 5, 21, respectively. , 32 are connected to the outer cases 5, 21, 32 via joint flanges 25, 26, 40, 41 protruding from the outer peripheral side of the filters 2, 3, the inner cases 4, 20, 31 and A plurality of combinations of the outer cases 5, 21, and 32 are provided, and the joint flanges 25 and 26 (40 and 41) are clamped and fixed by a pair of clamping flanges 51 and 52 (53 and 54). Since the plurality of outer cases 5, 21, 32 are connected, the adjacent joining flanges 25, 26 (40, 41) are clamped from both sides by the both clamping flanges 51, 52 (53, 54). Can be pressed. In addition, since the sandwiching flanges 51 to 54 are configured separately without being welded to the outer cases 5, 21, and 32, welding is performed in the relationship between the sandwiching flanges 51 to 54 and the outer cases 5, 21, and 32. There is no possibility that the problem of stress concentration and distortion due to the above will occur. For this reason, it is possible to apply a substantially uniform pressure contact force to the entire joint flanges 25 and 26 (40, 41), and to maintain a high surface pressure on the sealing surfaces (clamping surfaces) of the clamping flanges 51 to 54. . As a result, there is an effect that the exhaust gas leakage from between the joint flanges 25 and 26 (40, 41) can be surely prevented.

  As apparent from the above description and FIGS. 6 and 23 to 28, at least one of the sandwiching flanges 51 to 54 supports the outer case 5, 21, 32 to the engine 70. Therefore, the support body 61 is also configured as a separate body without welding to the holding flanges 51 to 54, and the support body 61 and at least one of the holding flanges 51 to 54 are Also in the relationship between the two, the problem of stress concentration and distortion caused by welding can be avoided. Therefore, it is possible to improve the adhesion at the time of fastening between the support body 61 and at least one of the sandwiching flanges 51 to 54 and contribute to the improvement of rigidity.

  As is clear from the above description and FIGS. 6 and 23 to 28, each of the clamping flanges 51 to 54 is provided with a plurality of bolt fastening portions 55 and 57, and the support body 61 is fastened. Since the support flange fastening portion 59 is provided between the adjacent bolt fastening portions 55 in the sandwiching flange 53, for example, even if the support 61 is about to be deformed by stress due to vibration of the engine 70 or the like. By virtue of the action of the adjacent bolt fastening portions 61, it is possible to remarkably suppress the possibility of deformation to the support fastening portion 59 and thus the clamping flange 53. As a result, there is an effect that the possibility of exhaust gas leakage can be further reduced.

  As is apparent from the above description and FIGS. 6 and 23 to 28, each of the holding flanges 51 to 54 is divided into a plurality of units 51 a and 51 b (52 a) divided in the circumferential direction of the outer cases 5, 21 and 32. , 52b, 53a, 53b, 54a, 54b), and the plurality of units 51a, 51b (52a, 52b, 53a, 53b, 54a, 54b) surround the outer peripheral sides of the outer cases 5, 21, 32. Therefore, although the holding flanges 51 to 54 are configured by the plurality of units 51a and 51b (52a, 52b, 53a, 53b, 54a, and 54b), they are in the same state as that of the single unit. For this reason, assembly is easy and assembly workability can be improved. In addition, there is an effect that it is possible to provide the DPF 1 with high sealing performance while suppressing the processing cost and the assembling cost.

  Next, the detailed structure of each joining flange 25, 26, 40, 41 will be described with reference to FIGS. Here, since the structure of each joining flange 25, 26, 40, 41 is basically the same, the catalyst side joining flange 25 that is welded and fixed to the catalyst inner case and the catalyst outer case is taken as a representative example below. explain. Fig.29 (a) has shown the expanded side sectional drawing of the catalyst side joining flange 25 in embodiment. In the catalyst side joining flange 25 of FIG. 29 (a), the base end portion 25a located between the catalyst inner case 4 and the catalyst outer case 5 has a shape bent in a step shape. The presence of the step-like base end portion 25a of the catalyst side joining flange 25 exhibits a rib effect, and high rigidity of the catalyst side joining flange 25 is ensured. As described above, the protruding portion 25b of the catalyst side joining flange 25 is sandwiched by the sandwiching flanges 51 and 52.

  FIGS. 29B and 29C show another example of the joining structure of the catalyst side joining flanges 25 ′ and 25 ″. The catalyst side joining flanges 25 ′ and 25 ″ shown in FIGS. It is formed in a letter shape. In the first alternative example of FIG. 29B, the base end portion 25 a ′ along the longitudinal direction of the catalyst inner case 4 of the catalyst side joining flange 25 ′ is welded and fixed to the downstream end portion of the catalyst inner case 4. Yes. The downstream end of the catalyst outer case 5 is bent inward (catalyst inner case 4 side), and the distal end side of the bent is welded and fixed to the base end portion 25a ′ of the catalyst side joining flange 25 ′. The protruding portion 25b 'of the catalyst side joining flange 25' is sandwiched between the sandwiching flanges 51 and 52, as in the case of FIG. In the second alternative example of FIG. 29C, the base end portion 25 a ″ of the catalyst side joining flange 25 ″ is fixed to the downstream end portion of the catalyst inner case 4 by welding. The downstream end of the catalyst outer case 5 is welded and fixed to the protruding portion 25b "of the catalyst side joining flange 25" without being bent. These junction structures shown in FIGS. 29B and 29C can also be employed. In particular, when the joining structure shown in FIG. 29B is employed, the end of the catalyst outer case 5 on the downstream side is bent to form rigidity by the rib effect. Moreover, since the welded portion between the catalyst outer case 5 and the catalyst side joining flange 25 ′ is separated from the protruding portion 25 b ′ of the catalyst side joining flange 25 (the sealing surfaces (nipping surfaces) of the both sandwiching flanges 51 and 52), the diesel engine 70. These vibrations and stresses are unlikely to affect the welded portion between the catalyst outer case 5 and the catalyst side joining flange 25 ', and there is an advantage that the problem of stress concentration and distortion caused by welding can be avoided.

  As is clear from the above description and FIGS. 27 to 29, a plurality of gas purification filters 2 and 3 that purify exhaust gas from the engine 70, and a plurality of cases 4 that accommodate the gas purification filters 2 and 3. In the exhaust gas purifying apparatus 1 having 5, 20, 21, 31, 32, the adjacent cases 5, 21 (21, 32) are joined to flanges 25, 26 (40, 41) protruding from the outer peripheral side. ) And the connecting flanges 25 and 26 (40, 41) are connected by being clamped and fastened in the abutting direction by a pair of clamping flanges 51 and 52 (53, 54). 52 (53, 54) is constructed separately without being welded to the case 5, 21 (21, 32). For this reason, in the relationship between the clamping flanges 51 and 52 (53 and 54) and the cases 5 and 21 (21 and 32), problems of stress concentration and distortion caused by welding can be avoided. A substantially uniform pressure contact force can be applied to the entire joint flanges 25, 26 (40, 41), and the surface pressure of the sealing surfaces (clamping surfaces) of the clamping flanges 51, 52 (53, 54) can be maintained at a high level. The exhaust gas leakage from between the joint flanges 51 and 52 (53 and 54) can be reliably prevented.

  As apparent from the above description and FIGS. 27 to 29, each of the cases 4, 5, 20, 21, 31, 32 includes inner cases 4, 20, 31 containing the gas purification filters 2, 3; Outer cases 5, 21, and 32 containing the inner cases 4, 20, and 31, and the inner cases 4, 20, and 31 and the outer cases 5, 21, and 32 are connected to the joint flanges 25, 26, Since it is being fixed via 40, 41, the joining flanges 25, 26, 40, 41 can be used as members for connecting adjacent cases 4, 5, 20, 21, 31, 32. This contributes to improving the connection strength between the inner cases 4, 20, 31 and the outer cases 5, 21, 32.

(8). Others The present invention is not limited to the above-described embodiments, and can be embodied in various forms. For example, the engine according to the present invention can be widely applied to various vehicles such as agricultural working machines such as a combine and a tractor, and special work vehicles such as a backhoe and a forklift car. Moreover, the structure of each part in this invention is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

a Crank axis 1 DPF
2 Diesel oxidation catalyst 3 Soot filter 4, 20, 31 Inner case 5, 21, 32 Outer case 25, 26, 40, 41 Joint flange 51, 52, 53, 54 Holding flange 51a, 51b, 52a, 52b, 53a, 53b , 54a, 54b Unit 55, 57 Bolt fastening portion 56, 58 Bolt hole 59 Support fastening portion 60 DPF casing 61, 62 Bracket leg 70 Diesel engine 71 Exhaust manifold 73 Intake manifold 74 Crankshaft 75 Engine block 76 Cooling fan 78 Flywheel housing

Claims (1)

An engine device having an engine and an exhaust gas purification device having a filter for purifying exhaust gas discharged from the engine,
The exhaust gas purifying device has an inner case containing the filter, an outer case containing the inner case, and a differential pressure sensor for detecting a clogged state inside the device,
The inner case is connected to the outer case via a joint flange that protrudes to the outer peripheral side of the outer case, and includes a plurality of combinations of the filter, the inner case, and the outer case, and the joint flange. Are sandwiched and fixed by a pair of sandwiching flanges, whereby the plurality of outer cases are connected, and a support for supporting the outer case by the engine is fastened to at least one of the sandwiching flanges. And
An engine device characterized in that a detection main body of the differential pressure sensor is attached to a sensor bracket fixed to a front side surface of a cylinder head of the engine, and is arranged above the cylinder head.

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