WO2010092857A1

WO2010092857A1 - Engine device

Info

Publication number: WO2010092857A1
Application number: PCT/JP2010/050593
Authority: WO
Inventors: 恭志小野寺; 義幸山東; 匡孝光田
Original assignee: ヤンマー株式会社
Priority date: 2009-02-10
Filing date: 2010-01-20
Publication date: 2010-08-19

Abstract

An EGR cooler (147) which constitutes an EGR device (91) is adapted to be less susceptible to heat from a diesel engine (70). An engine device for mounting on a working vehicle, the engine device being provided with the diesel engine (70) having an intake manifold (71) and an exhaust manifold (73), and also with the EGR device (91) for recirculating, as an EGR gas, a part of the exhaust gas, which is discharged from the exhaust manifold (73), to the intake manifold (71). The EGR cooler (147) for cooling the EGR gas is provided in a recirculation conduit which connects the exhaust manifold (73) and the intake manifold (71). The gas inlet side of the EGR cooler (147) is connected and communicated with the exhaust manifold (73) through an EGR gas take-out pipe (177) while the gas outlet side of the EGR cooler (147) is mounted to the diesel engine (70) through a support member (180), and the EGR cooler is supported by the EGR gas take-out pipe (177) and the support member (180) so as to be separated from the outer surface of the diesel engine (70).

Description

Engine equipment

The present invention relates to an engine device used for a work vehicle such as a forklift, a backhoe or a tractor.

In recent years, due to the application of higher-level exhaust gas regulations related to diesel engines, exhaust gas purification devices that purify air pollutants in exhaust gas are being applied to agricultural machinery, construction machinery, ships, etc., on which diesel engines are mounted. It is being requested to install. As exhaust gas purifying devices, DPF (diesel particulate filter), NOx catalyst, and the like are known (see Patent Documents 1 to 3). In addition, as an exhaust gas countermeasure, an EGR device (exhaust gas recirculation device) that recirculates part of the exhaust gas to the intake side is provided, so that the combustion temperature is kept low and the amount of NOx (nitrogen oxide) in the exhaust gas is reduced. The technique of reducing is also known (refer patent document 4).

In the EGR device of Patent Document 4, a reflux pipe branched from an exhaust manifold of a diesel engine is connected to an intake manifold. By supplying a part of the exhaust gas (EGR gas) to the intake manifold via the reflux line, the EGR gas and fresh air from the intake side are mixed. The mixed gas is introduced into each cylinder (inside the intake stroke) of the diesel engine.

Also, an EGR cooler that uses the cooling water of the diesel engine as a refrigerant is disposed in the reflux pipe. In this case, the EGR gas flowing through the reflux pipe is heat-exchanged by the EGR cooler, and the EGR gas temperature is lowered. As a result, the combustion temperature is kept low while suppressing the generation of black smoke (smoke) during combustion, and the effect of reducing the amount of NOx in the exhaust gas is enhanced.

JP 2000-145430 A Japanese Patent Laid-Open No. 2003-27922 JP 2008-82201 A JP 2000-282916 A

However, since the EGR cooler of Patent Document 4 is connected to the exhaust manifold in a posture along the side of the exhaust manifold, the EGR cooler easily receives exhaust heat from the exhaust manifold, and overheating causes damage to the EGR cooler. There is concern about fear. Moreover, in order to suppress the influence of the exhaust heat from the exhaust manifold, it is necessary to improve the cooling performance of the EGR cooler, which causes a problem of increasing the size of the EGR cooler.

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

The invention according to claim 1 is an engine device comprising a diesel engine having an intake manifold and an exhaust manifold, and an EGR device that recirculates a part of the exhaust gas discharged from the exhaust manifold as EGR gas to the intake manifold. An EGR cooler for cooling EGR gas is disposed in a reflux pipe connecting the exhaust manifold and the intake manifold, and the gas inlet side of the EGR cooler is communicated with the exhaust manifold via an EGR gas take-out pipe. While connecting, the gas outlet side of the EGR cooler is attached to the diesel engine via a support member, and the EGR cooler is supported by being separated from the outer surface of the diesel engine by the EGR gas take-out pipe and the support member. It is configured.

According to a second aspect of the present invention, in the engine device according to the first aspect, an EGR gas discharge line for communicating the EGR cooler and the reflux line is formed in the support member.

According to a third aspect of the present invention, there is provided an engine device according to the first aspect, wherein an exhaust gas purification device for purifying exhaust gas from the diesel engine, an inlet side exhaust pressure and an outlet side exhaust pressure of the exhaust gas purification device. The exhaust pressure detection means for detecting the pressure difference between the exhaust pressure detection means and the exhaust pressure detection means is attached to the outer surface of the diesel engine via a support bracket.

According to a fourth aspect of the present invention, in the engine device according to the third aspect, a sensing body provided at a distal end portion of a harness extending from the detection main body is attached to the exhaust gas purification device, and an outer surface of the exhaust gas purification device is provided. A plate member provided on the outer surface side of the exhaust gas purifying device is configured to support a longitudinal midway portion of the harness so as to be separated from the harness.

According to the first aspect of the present invention, an engine device comprising a diesel engine having an intake manifold and an exhaust manifold, and an EGR device that recirculates a part of the exhaust gas discharged from the exhaust manifold to the intake manifold as EGR gas. An EGR cooler for cooling EGR gas is disposed in a reflux line connecting the exhaust manifold and the intake manifold, and a gas inlet side of the EGR cooler is connected to the exhaust manifold via an EGR gas take-out pipe. While connecting to the diesel engine, a gas outlet side of the EGR cooler is attached to the diesel engine via a support member, and the EGR cooler is supported by being separated from the outer surface of the diesel engine by the EGR gas take-out pipe and the support member. It is configured as From comprises heat generated by the diesel engine is easily transmitted to the EGR cooler. Therefore, damage to the EGR cooler due to overheating can be suppressed. When the diesel engine is provided with a cooling fan, it is possible to allow cooling air to pass between the outer surface of the diesel engine and the EGR cooler, so that heat transfer from the diesel engine to the EGR cooler can be further improved. This further suppresses the cooling efficiency of the EGR cooler by the cooling air.

According to the second aspect of the present invention, since the EGR gas discharge pipe that connects the EGR cooler and the reflux pipe is formed in the support member, the support member that supports the EGR cooler is made of EGR gas. It can be used as part of the distribution channel and can contribute to the reduction of the number of parts related to the EGR device.

According to the invention of claim 3, an exhaust gas purification device for purifying exhaust gas from the diesel engine, and an exhaust pressure for detecting a pressure difference between an inlet side exhaust pressure and an outlet side exhaust pressure of the exhaust gas purification device. The detection body of the exhaust pressure detection means is attached to the outer surface of the diesel engine via a support bracket, so that the detection body of the exhaust pressure detection means is the diesel engine itself. It will be arranged away from. For this reason, it is difficult for heat generated by the diesel engine to be transmitted to the detection body. Therefore, although the detection main body is assembled to the diesel engine, the detection main body can be prevented from malfunctioning due to overheating.

According to the invention of claim 4, a sensing body provided at a tip of a harness extending from the detection main body is attached to the exhaust gas purification device, and the outer surface of the exhaust gas purification device and the harness can be separated from each other, Since the plate member provided on the outer surface side of the exhaust gas purifying apparatus is configured to support the midway part of the harness in the longitudinal direction, it is possible to suppress vibration of the harness due to vibration of the diesel engine. For this reason, the harness and the sensing body can be prevented from loosening and coming off, and detection by the exhaust pressure detecting means can be performed normally. In addition, because of the presence of the plate member, there is a gap between the outer surface of the exhaust gas purifying device and the harness, so that the adverse effect of the heat generated by the exhaust gas purifying device does not easily affect the harness. Accordingly, there is an effect of suppressing damage to the harness due to overheating.

It is a front view sectional view of DPF in an embodiment. It is the same external appearance bottom view. FIG. 2 is an exploded front sectional view of FIG. 1. It is a left view of a diesel engine. It is a right view of a diesel engine. It is a top view of a diesel engine. It is a rear side view of a diesel engine. It is a front side view of a diesel engine. It is a left view of the diesel engine which shows the state which omitted the alternator. It is a rear side view of the diesel engine which shows the state which omitted DPF. It is expansion explanatory drawing of an EGR cooler. It is an expanded sectional side view of a supporting member. It is a side view of a backhoe. It is a top view of a backhoe. It is a side view of a forklift car. It is a top view of a forklift car. FIG. 9 is an enlarged front side view of FIG. 8. It is a front side view of the diesel engine which shows the state which omitted a cooling fan, an alternator, etc. FIG. 19 is an enlarged front side view of FIG. 18.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the exhaust gas inflow side is simply referred to as the left side, and the exhaust gas discharge side is simply referred to as the right side.

(1). First, the overall structure of the exhaust gas purifying apparatus will be described with reference to FIGS. As shown in FIGS. 1 to 3, a continuous regeneration type diesel particulate filter 1 (hereinafter referred to as DPF) is provided as an exhaust gas purification device. The DPF 1 is for physically collecting particulate matter (PM) in the exhaust gas. The DPF 1 of the embodiment includes a diesel oxidation catalyst 2 such as platinum that generates nitrogen dioxide (NO ₂ ), and a soot filter 3 having a honeycomb structure that continuously oxidizes and removes the collected particulate matter (PM) at a relatively low temperature. Are arranged in series in the moving direction of the exhaust gas (from the left side to the right side in FIG. 1). The DPF 1 is configured so that the soot filter 3 is continuously regenerated. The DPF 1 can reduce carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas in addition to the removal of particulate matter (PM) in the exhaust gas.

(2). Diesel Oxidation Catalyst Mounting Structure With reference to FIGS. 1 to 3, the diesel oxidation catalyst 2 mounting structure will be described. As shown in FIGS. 1 to 3, a diesel oxidation catalyst 2 as a gas purification filter for purifying exhaust gas discharged from a diesel engine 70 described later is provided in a substantially cylindrical catalyst inner case 4 made of a heat-resistant metal material. ing. 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 mat-shaped ceramic fiber catalyst heat insulating material 6. Further, the catalyst outer case 5 is fitted on the outer side of the catalyst inner case 4 via a thin plate support 7 having an I-shaped end face. 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. 1 to 3, a disc-shaped left lid 8 is fixed to the left end of the catalyst inner case 4 and the catalyst outer case 5 by welding. A sensor connection plug 10 is fixed to the left lid body 8 through a seat plate body 9. The left end face 2a of the diesel oxidation catalyst 2 and the left 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. A sensor connection plug 10 is fixed to a portion of the exhaust gas inflow space 11 in the catalyst inner case 4 and the catalyst outer case 5. An inlet side sensing body 64 of a differential pressure sensor 60 as exhaust pressure detecting means for detecting the pressure of exhaust gas in the exhaust gas inflow space 11 is inserted into the sensor connection plug 10 (see FIGS. 4, 6 and 6). 7).

1 and 3, an elliptical exhaust gas inlet 12 is opened at the left end of the catalyst inner case 4 and the catalyst outer case 5 in which the exhaust gas inflow space 11 is formed. The elliptical exhaust gas inlet 12 has a short diameter in the exhaust gas movement direction (center line direction of the cases 4 and 5) and a direction orthogonal to the exhaust gas movement direction (circumferential direction of the cases 4 and 5). It has a long diameter. A closing ring body 15 is fixed between the opening edge 13 of the catalyst inner case 4 and the opening edge 14 of the catalyst outer case 5 in a sandwiched manner. A gap between the opening edge 13 of the catalyst inner case 4 and the opening edge 14 of the catalyst outer case 5 is closed by the closing ring body 15. An exhaust ring 15 prevents the exhaust gas from flowing between the catalyst inner case 4 and the catalyst outer case 5.

As shown in FIGS. 1 and 3, 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. An exhaust connection flange body 17 is welded to a true circular opening end portion 16 a on the small diameter side of the exhaust gas inlet pipe 16. Although details will be described later, the exhaust connection flange body 17 is connected to a first relay pipe 84 connected to an exhaust throttle device 86 of the diesel engine 70 via a bolt 18. A large circular opening end 16 b on the large diameter side of the exhaust gas inlet pipe 16 is welded to the outer surface of the catalyst outer case 5. The exhaust gas inlet pipe 16 is formed in a divergent shape (a trumpet shape) from the small-diameter-side perfect circular opening end 16a toward the large-diameter-side perfect circular opening end 16b.

As shown in FIGS. 1 and 3, a large-diameter open end 16 b formed in a true circle is formed at the left end of the outer surface of the catalyst outer case 5, and an open edge 14 is formed by the exhaust gas inlet pipe 16. It is welded to cover it. In this case, the exhaust gas inlet pipe 16 (large-diameter-side opening end portion 16b) is offset with respect to the elliptical exhaust gas inlet 12, and is arranged offset to the exhaust gas movement downstream side (right side of the catalyst outer case 5). Has been. That is, the elliptical exhaust gas inlet 12 is offset to the exhaust gas movement upstream side (the left side of the catalyst outer case 5) with respect to the exhaust gas inlet pipe 16 (large-diameter side opening end portion 16b).

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. When the DPF 1 is assembled to the diesel engine 70, the catalyst outer case 5 is fixed to the flywheel housing 78 of the diesel engine 70 via the support leg 19.

(3). Soot Filter Mounting Structure The soot filter 3 mounting structure will be described with reference to FIGS. 1 and 3. As shown in FIGS. 1 and 3, the soot filter 3 as a gas purification filter for purifying exhaust gas discharged from the diesel engine 70 is provided in a substantially cylindrical filter inner case 20 made of a heat-resistant metal material. The inner case 4 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 via the mat-shaped ceramic fiber filter heat insulating material 22. The soot filter 3 is protected by the filter heat insulating material 22.

1 and 3, the catalyst side flange 25 is welded to the end of the catalyst outer case 5 on the downstream side (right side) of the exhaust gas movement. The filter-side flange 26 is welded to the middle of the filter inner case 20 in the exhaust gas movement direction and the end of the filter outer case 21 on the upstream side (left side) of the exhaust gas movement. The catalyst side flange 25 and the filter side flange 26 are detachably fastened by bolts 27 and nuts 28. The diameter of the cylindrical catalyst inner case 4 and the diameter of the cylindrical filter inner case 20 are substantially the same. 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. 1, in a state where the filter outer case 21 is connected to the catalyst outer case 5 via the catalyst side flange 25 and the filter side flange 26, the exhaust gas movement downstream side (right side) end of the catalyst inner case 4 is shown. The end portion on the upstream side (left side) of the exhaust gas movement of the filter inner case 20 faces the portion spaced apart by a fixed interval L2 for sensor attachment. In other words, the sensor mounting space 29 is formed between the exhaust gas movement downstream side (right side) end of the catalyst inner case 4 and the exhaust gas movement upstream side (left side) end of the filter inner case 20. A sensor connection plug 50 is fixed to the catalyst outer case 5 at the sensor mounting space 29 position. For example, an inlet side exhaust gas temperature sensor (thermistor, not shown) is connected to the sensor connection plug 50.

As shown in FIG. 3, the cylindrical length L4 of the catalyst outer case 5 in the exhaust gas movement direction is longer than the cylindrical length L3 of the catalyst inner case 4 in the exhaust gas movement direction. 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. A length (L2 + L3 + L5) obtained by adding the constant interval L2 of the sensor mounting space 29, the cylindrical length L3 of the catalyst inner case 4 and the cylindrical length L5 of the filter inner case 20 is the cylindrical length L4 of the catalyst outer case 5. And a length (L4 + L6) obtained by adding the cylindrical length L6 of the filter outer case 21 to be substantially equal to each other.

The exhaust gas movement upstream side (left side) end of the filter outer case 21 is connected to the exhaust gas movement upstream side (left side) end of the filter inner case 20 by a difference in length (L7 = L5-L6). Protruding. That is, when the filter outer case 21 is connected to the catalyst outer case 5, the exhaust gas movement upstream side (left side) end of the filter inner case 20 is the overlap dimension L7, and the exhaust gas movement downstream side of the catalyst outer case 5 (Right side) is interpolated.

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 left end face 3a. The collected particulate matter (PM) in the exhaust gas of the diesel engine 70 collected by the soot filter 3 is continuously oxidized and removed at a relatively low temperature 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 described above, the diesel oxidation catalyst 2 and the soot filter 3 are provided as gas purification filters for purifying the exhaust gas discharged from the engine. However, instead of the diesel oxidation catalyst 2 and the soot filter 3, urea (reducing agent) is used. NOx selective reduction catalyst (NOx removal catalyst) for reducing nitrogen oxides (NOx) in the exhaust gas of the engine 70 by ammonia (NH ₃ ) generated by the addition of ( ₃ )), and residual ammonia discharged from the NOx selective reduction catalyst An ammonia removal catalyst that removes water may be provided.

As described above, when the NOx selective reduction catalyst (NOx removal catalyst) is provided in the catalyst inner case 4 and the ammonia removal catalyst is provided in the filter inner case 20 as the gas purification filter, the oxidation of nitrogen in the exhaust gas exhausted by the engine is performed. The substance (NOx) is reduced and can be discharged as harmless nitrogen gas (N ₂ ).

(4). Silencer Mounting Structure With reference to FIGS. 1 to 3, the silencer mounting structure will be described. As shown in FIGS. 1 to 3, the silencer 30 for attenuating the exhaust gas sound discharged from the diesel engine 70 includes a substantially cylindrical silencer inner case 31 made of a heat resistant metal material and a substantially cylindrical shape made of a heat resistant metal material. The sound-absorbing outer case 32, and the sound-absorbing inner case 31 and the disc-shaped right-side cover 33 fixed to the right end of the sound-absorbing outer case 32 by welding are provided. A silencer inner case 31 is provided in the silencer outer case 32. The diameter of the cylindrical catalyst inner case 4, the diameter of the cylindrical filter inner case 20, and the cylindrical muffler inner case 31 are substantially the same. Further, the diameter size of the cylindrical catalyst outer case 5, the diameter size of the cylindrical filter outer case 21, and the cylindrical silencing outer case 32 are substantially the same size.

An exhaust gas outlet pipe 34 is passed through the silencer inner case 31 and the silencer outer case 32. One end side of the exhaust gas outlet pipe 34 is closed by an outlet lid 35. A number of exhaust holes (not shown) are formed in the entire exhaust gas outlet pipe 34 inside the silencer inner case 31. The interior of the muffler inner case 31 communicates with the exhaust gas outlet pipe 34 through the numerous exhaust holes described above. A tail pipe 135 and an existing silencing member (not shown) to be described later are connected to the other end side of the exhaust gas outlet pipe 34.

In addition, the inside of the muffling inner case 31 is communicated between the muffling inner case 31 and the muffling outer case 32 through a number of muffler holes (not shown). The space between the silencer inner case 31 and the silencer outer case 32 is closed by the right lid 33 or the like. A ceramic fiber silencer (not shown) is filled between the silencer inner case 31 and the silencer outer case 32. The end of the silencing inner case 31 on the upstream side (left side) of the exhaust gas movement is connected to the end of the silencing outer case 32 on the upstream side (left side) of the exhaust gas movement via a thin plate support (not shown). Yes.

With the above configuration, exhaust gas is discharged from the muffler inner case 31 through the exhaust gas outlet pipe 34. Further, in the silencer inner case 31, exhaust gas sound (mainly high frequency band sound) is absorbed by the silencer material from a large number of silencer holes. Therefore, the noise of the exhaust gas discharged from the outlet side of the exhaust gas outlet pipe 34 is attenuated.

1 and 3, the filter side outlet flange 40 is welded to the exhaust gas movement downstream side (right side) ends of the filter inner case 20 and the filter outer case 21. The silencer flange 41 is welded to the exhaust gas movement upstream side (left side) of the silencer outer case 32. The filter side outlet flange 40 and the silencer side flange 41 are detachably fastened by bolts 42 and nuts 43. A sensor connection plug 44 is fixed to the filter inner case 20 and the filter outer case 21. An outlet-side sensing body 65 of a differential pressure sensor 60 as exhaust pressure detecting means for detecting the pressure of exhaust gas in the muffler inner case 31 is inserted into the sensor connection plug 44 (see FIGS. 4, 6, and 7). reference).

(5). Structure in which DPF and EGR device are provided in diesel engine Next, a structure in which the DPF 1 and EGR device 91 are provided in the diesel engine 70 will be described with reference to FIGS. As shown in FIGS. 4 to 7, an exhaust manifold 71 is disposed on the left side surface of the cylinder head 72 of the diesel engine 70. An intake manifold 73 is disposed on the right side surface of the cylinder head 72. The cylinder head 72 is mounted on a cylinder block 75 having an engine output shaft 74 (crank shaft, see FIG. 7) and a piston (not shown). Front and rear front ends of the engine output shaft 74 are projected from both front and rear side surfaces of the cylinder block 75, respectively. A cooling fan 76 is provided on the front side surface of the cylinder block 75. The rotational force is transmitted from the front end side of the engine output shaft 74 to the cooling fan 76 via the V belt 77.

4 to 8, a flywheel housing 78 is fixed to the rear side of the cylinder block 75. A flywheel 79 is provided in the flywheel housing 78. A flywheel 79 is pivotally supported on the rear end side of the engine output shaft 74. The power of the diesel engine 70 is taken out via the flywheel 79 to the working part of the work vehicle (backhoe 100, forklift car 120, etc.).

Further, an oil pan 95 is disposed on the lower surface of the cylinder block 75. Lubricating oil is stored in the oil pan 95. Lubricating oil in the oil pan 95 is sucked by an oil pump 156 disposed in a portion near the right side surface in the cylinder block 75 and is passed through an oil filter 157 disposed on the right side surface of the cylinder block 75, and the diesel engine. 70 is supplied to each lubrication section. The lubricating oil supplied to each lubricating part is then returned to the oil pan 95. The oil pump 156 is configured to be driven by rotation of the engine output shaft 74.

A fuel injection pump 158 for supplying fuel to the combustion chamber in the cylinder block 75 is attached above the oil filter 157 on the right side surface of the cylinder block 75 (below the intake manifold 73). The fuel injection pump 158 includes an electronic governor and a fuel feed pump for adjusting the fuel injection amount. By driving the fuel feed pump, the fuel in the fuel tank is sent to the fuel injection pump 158 via the fuel filter.

A cooling water pump 159 for lubricating lubricating water is disposed coaxially with the fan shaft 80 of the cooling fan 76 at a portion on the left side of the front surface of the cylinder block 75. The cooling water pump 159 is configured to be driven together with the cooling fan 76 by the rotation of the engine output shaft 74. Cooling water in a radiator 134 (described in detail later) mounted on the work vehicle is supplied to the cooling water pump 159 via a thermostat case 160 provided on the upper part of the cooling water pump 159. Then, by driving the cooling water pump 159, cooling water is supplied to a water cooling jacket (not shown) formed in the cylinder head 72 and the cylinder block 75 to cool the diesel engine 70. Cooling water that has contributed to cooling the diesel engine 70 is returned to the radiator 134.

In the embodiment, the engine output shaft 74 and the fan shaft 80 of the cooling fan 76 extend in parallel in the vertical direction. As shown in FIG. 6, a cooling water pump 159 is disposed on the exhaust manifold 71 side and an oil pump 156 is disposed on the intake manifold 73 side with the engine output shaft 74 (fan shaft 80) interposed therebetween in plan view. In view of the positional relationship, the cooling water pump 159 faces the cooling fan 76, and the cooling air from the cooling fan 76 hits the cooling water pump 159. An alternator 161 is provided on the left side of the cooling water pump 159.

Engine leg mounting portions 96 are provided on the left and right side surfaces of the cylinder block 75 and the left and right side surfaces of the flywheel housing 78, respectively. Each engine leg mounting portion 96 is bolted to an engine leg body 97 having vibration-proof rubber. The diesel engine 70 is supported in an anti-vibration manner on an engine mounting chassis 81 such as a work vehicle (backhoe 100, forklift car 120) via each engine leg 97.

As shown in FIG. 5, the inlet portion of the intake manifold 73 protrudes upward from the substantially central portion of the intake manifold 73. The inlet portion of the intake manifold 73 is connected to an air cleaner (not shown) via an EGR device 91 (exhaust gas recirculation device). 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 via the EGR device 91, and is supplied to each cylinder of the diesel engine 70.

As shown in FIGS. 5 and 6, the EGR device 91 mixes a part of exhaust gas of the diesel engine 70 (EGR gas from the exhaust manifold 71) and fresh air (external air from the air cleaner 88) to intake air. An EGR main body case (collector) 145 to be supplied to the manifold 73, an intake throttle member 146 for communicating the EGR main body case 145 with an air cleaner, and a recirculation exhaust as a return line connected to the exhaust manifold 71 via an EGR cooler 147 A gas pipe 148 and an EGR valve member 149 that allows the EGR main body case 145 to communicate with the recirculated exhaust gas pipe 148 are provided.

That is, the intake manifold 73 and the intake air intake throttle member 146 are connected via the EGR main body case 145. The EGR main body case 145 communicates with the outlet side of the recirculated exhaust gas pipe 148 extending from the exhaust manifold 71. As shown in FIG. 6, the EGR main body case 145 is formed in a long cylindrical shape. The intake throttle member 146 is bolted to one end of the EGR main body case 145 in the longitudinal direction. A downward opening end formed in a portion of the EGR main body case 145 opposite to the intake throttle member 146 is detachably bolted to the inlet portion of the intake manifold 73.

As shown in FIGS. 4 to 6, the EGR main body case 145 is provided with two

temperature sensors

151 and 153 as temperature detecting means. A fresh air temperature sensor 151 that detects the temperature of fresh air from the air cleaner is disposed in a portion of the EGR main body case 145 near the intake throttle member 146. A mixed gas temperature sensor 153 that detects the temperature of the mixed gas is disposed at a portion of the intake manifold 73 near the inlet 73a. In addition, an EGR gas temperature sensor 152 as temperature detecting means for detecting the temperature of the EGR gas from the exhaust manifold 71 is attached to the EGR valve member 149 (recirculation exhaust gas pipe 148). The temperature sensors 151 to 153 are used for obtaining 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 the embodiment, the outlet side of the recirculation exhaust gas pipe 148 is connected to the EGR main body case 145 via the EGR valve member 149. The EGR valve member 149 adjusts the supply amount of EGR gas to the EGR main body case 145 by adjusting the opening degree of an EGR valve (not shown) in the EGR valve member 149. An opening end projecting obliquely downward from the outer peripheral surface of the EGR valve member 149 is connected to a longitudinal midway portion of the EGR main body case 145. The inlet side of the recirculated exhaust gas pipe 148 is connected to the lower surface side of the exhaust manifold 71 via an EGR cooler 147.

As shown in FIGS. 5 and 6, the intake throttle member 146 and the EGR valve member 149 are assembled in a common EGR main body case 145. In other words, the intake throttle member 146, the EGR main body case 145, and the EGR valve member 149 are unitized as one member. The intake throttle member 146, the EGR main body case 145, and the EGR valve member 149 are positioned (exposed) on the intake manifold 73 so that the cooling air from the cooling fan 76 strikes these

members

145, 146, and 149. It is configured.

With the above configuration, fresh air (external air) is supplied from the air cleaner through the intake throttle member 146 into the EGR main body case 145, while EGR gas (from the exhaust manifold 71 to the EGR main body case 145 through the EGR valve 149 is A part of the exhaust gas discharged from the exhaust manifold 71 is supplied. After fresh air from the air cleaner and EGR gas from the exhaust manifold 71 are mixed in the EGR main body case 145, the mixed gas in the EGR main body case 145 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 at the time of high load operation is lowered. NOx (nitrogen oxide) emissions are reduced.

As is clear from the above configuration, according to the EGR device 91 of the embodiment, the intake manifold 73 and the intake air intake throttle member 146 are connected via the EGR main body case 145, and are connected to the EGR main body case 145. Since the outlet side of the recirculation exhaust gas pipe 148 extending from the exhaust manifold 71 communicates, 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 mixed state in the mixed gas is reduced before being sent to the intake manifold 73. Therefore, a mixed gas with little unevenness can be distributed to each cylinder of the diesel engine 70, and variations in the EGR rate between the cylinders can be suppressed. As a result, the amount of NOx can be efficiently reduced while suppressing the generation of black smoke and keeping the combustion state of the diesel engine 70 in good condition.

In addition, since the intake throttle member 146, the EGR main body case 145, and the EGR valve member 149 are unitized as one member, they are different models of various work vehicles (for example, the backhoe 100 and the forklift car 120). However, these

members

145, 146 and 149 can be shared as a gas mixing unit. Therefore, each model equipped with the same type of diesel engine 70 can be dealt with by a single gas mixing unit configuration, so that the EGR rate for each model equipped with the same type of diesel engine 70 is suppressed from varying. Therefore, it is possible to omit the trouble of confirming the test and applying for shipping for each model. As a result, the manufacturing cost can be suppressed. It is also possible to reduce the assembly adjustment man-hours for performance matching between the EGR device 91 and the diesel engine 70.

Further, the intake throttle member 146, the EGR main body case 145, and the EGR valve member 149 are positioned (exposed) on the intake manifold 73 so that the cooling air from the cooling fan 76 strikes these

members

145, 146, and 149. Therefore, it is possible to suppress an increase in the temperature of the gas mixing unit due to the cooling air, and hence the mixed gas temperature therein, and to easily maintain the NOx reduction effect by the mixed gas in an appropriate state. In addition, the cooling performance of the EGR cooler 147 can be reduced by the amount by which the cooling air from the cooling fan 76 can suppress the rise of the gas mixing unit and thus the temperature of the mixed gas inside the unit. Become.

As shown in FIGS. 4 to 6, one end side of a plate-like support leg 19 as a filter support is welded and fixed to the catalyst outer case 5. The other end side of the support leg 19 is fastened to a DPF attachment portion 82 formed on the upper surface of the flywheel housing 78 by a bolt 83 so as to be detachable. For this reason, the above-described DPF 1 is supported by the high-rigidity flywheel housing 78 via both support legs 19.

As shown in FIGS. 4 to 7, the DPF 1 of the embodiment has a shape that is long in a direction orthogonal to the engine output shaft 74, and the exhaust gas movement direction is higher than that of the engine output shaft 74 above the flywheel housing 78. It arrange | positions away from the upper surface of the diesel engine 70 so that it may become a direction orthogonal. Therefore, the upper surfaces of the cylinder head 72, the exhaust manifold 72, and the intake manifold 73 are exposed, and the maintenance work is easily performed. In this case, the DPF 1 is located in the vicinity of the cylinder head 72. Specifically, the cylinder head 72 is disposed opposite to the rear side surface near the flywheel housing 78.

Further, as shown in FIG. 4, the upper end of the DPF 1 is lower than the upper end of the diesel engine 70 (cylinder head 72). When the diesel engine 70 is viewed from the cooling fan 76 side (see FIG. 8), most of the DPF 1 is hidden by the diesel engine 70. Further, the exhaust gas inlet pipe 16 and the exhaust gas outlet pipe 34 are arranged on the left and right sides of the DPF 1 at one end in the longitudinal direction and the other end in the longitudinal direction.

4 to 7, a plate member 53 extending along the longitudinal direction of the DPF 1 is attached to the outer surface side of the DPF 1. The plate member 53 is for supporting the

harnesses

62 and 63 group (details will be described later) of the differential pressure sensor 60, and the long plate-like long main body 54 and the same direction from both ends of the long main body 54. It is comprised by the

connection arm part

55 and 56 which protrudes. The left connecting arm portion 55 is fastened together with the seat plate body 9 by bolts and nuts that fix the seat plate body 9 to the left side lid body 8 of the DPF 1. The right connecting arm portion 56 is fastened together with the catalyst side flange 25 and the filter side flange 26 by bolts 27 and nuts 28.

In the embodiment, in a state where the plate member 53 is attached to the outer surface side of the DPF 1, the distance between the outer surface of the DPF 1 (catalyst outer case 5) and the base (long body 54) of the plate member 53 is set. ing. In this case, the plate member 53 is arranged in such a posture as to straddle the seat plate body 9 of the DPF 1, the catalyst side flange 25 and the filter side flange 26, so that the outer surface of the DPF 1 (catalyst outer case 5) and the plate member 53 are disposed. Is spaced from the base (the long main body 54).

As shown in FIG. 4, the outlet of the exhaust manifold 71 protrudes upward from the left end side of the exhaust manifold 71. An outlet portion of the exhaust manifold 71 is detachably connected to the exhaust gas inlet pipe 16 via an exhaust throttle device 86 for adjusting the exhaust pressure of the diesel engine 70. In the embodiment, the inlet side of the first relay pipe 84 is bolted to the outlet portion of the exhaust manifold 71, and the outlet side of the first relay pipe 84 is bolted to the inlet side of the exhaust throttle device 86. The outlet side of the exhaust throttle device 86 is bolted to the inlet side of the second relay pipe 85, and the outlet side of the second relay pipe 85 is bolted to the exhaust connection flange body 17 of the exhaust gas inlet pipe 16. Therefore, the above-described DPF 1 is supported by the highly rigid exhaust manifold 71 via the first and

second relay pipes

84 and 85 and the exhaust throttle device 86.

The exhaust throttle device 86 is for increasing the exhaust pressure of the diesel engine 70 as described above. That is, when soot accumulates on the soot filter 3, the exhaust gas temperature from the diesel engine 70 is increased by increasing the exhaust pressure of the diesel engine 70 by controlling the operation of the exhaust throttle device 86. The soot accumulated on the soot filter 3 burns. As a result, the soot disappears and the soot filter 3 is regenerated.

For this reason, the soot filter 3 can be regenerated by forcibly increasing the exhaust pressure by the exhaust throttle device 86 even if the work with a small load and the temperature of the exhaust gas is easily reduced (the work in which soot is likely to accumulate) is continuously performed. The exhaust gas purification capacity of the DPF 1 can be properly maintained. Further, a burner or the like for burning the soot deposited on the soot filter 3 becomes unnecessary.

Further, even when the engine is started, by increasing the exhaust pressure of the diesel engine 70 by the control of the exhaust throttle device 86, the temperature of the exhaust gas from the diesel engine 70 can be raised to promote the warm-up of the diesel engine 70. .

The exhaust gas that has moved from the outlet of the exhaust manifold 71 into the DPF 1 via the exhaust gas inlet pipe 16 is purified by the DPF 1 and then moved from the exhaust gas outlet pipe 34 to the tail pipe (not shown). Eventually it will be discharged out of the machine.

As is clear from the above configuration, the DPF 1 of the embodiment is connected to the exhaust manifold 71 of the engine 70 and is connected to the flywheel housing 78 via a plurality of filter supports (support legs 19). . For this reason, as one of the components of the diesel engine 70, the DPF 1 can be disposed with high rigidity in the diesel engine 70, the exhaust gas countermeasures for each equipment such as a work vehicle can be dispensed with, and the versatility of the diesel engine 70 can be improved. There is an effect.

That is, the use of the flywheel housing 78, which is a highly rigid part of the diesel engine 70, supports the DPF 1 with high rigidity and prevents damage to the DPF 1 due to vibration or the like. Further, it is possible to ship the DPF 1 incorporated in the diesel engine 70 at the manufacturing site of the diesel engine 70, and there is an advantage that the diesel engine 70 and the DPF 1 can be configured in a compact manner.

Further, since the DPF 1 can be communicated with the exhaust manifold 71 at a close distance, the DPF 1 can be easily maintained at an appropriate temperature, and high exhaust gas purification performance can be maintained. In addition, the DPF 1 can be reduced in size.

4-7, the DPF 1 is long in the direction orthogonal to the engine output shaft 74, and is disposed away from the upper surface of the diesel engine 70. Therefore, the cylinder head 72, the exhaust manifold 72, and The upper surface side of the intake manifold 73 can be exposed, and maintenance work related to the diesel engine 70 is easy.

As shown in FIGS. 4 to 7, since the DPF 1 is disposed in the vicinity of the cylinder head 72 located at the upper part of the diesel engine 70, the DPF 1 is located in the lee of the cooling fan 76 of the diesel engine 70. It will be hidden behind. Therefore, the wind from the cooling fan 76 can be prevented from directly hitting the DPF 1, and the decrease of the DPF 1 and the exhaust gas temperature inside the DPF 1 due to the wind from the cooling fan 76 can be suppressed, so that the exhaust gas temperature can be maintained. .

Now, on the outer surface of the diesel engine 70, a detection main body 61 of a differential pressure sensor 60, which is an exhaust pressure detection means, is attached via a support bracket 59. In the embodiment, a support bracket 59 having a square cross section is bolted to the rear side of the cylinder head 72 near the flywheel housing 78 (see FIGS. 6 and 7). The upper portion of the support bracket 59 extends so as to cover the upper surface of the head cover 90 that covers the upper surface of the cylinder head 72 in plan view. The detection main body 61 is screwed to the upper surface side of the support bracket 59. Therefore, the detection main body 61 is located away from the upper surface of the head cover 90.

The differential pressure sensor 60 which is an exhaust pressure detecting means is for detecting a pressure difference between the upstream side and the downstream side across the soot filter 3 in the DPF 1. By operating the exhaust throttle device 86 based on the pressure difference detected by the differential pressure sensor 60, regeneration control of the soot filter 3 is executed.

The differential pressure sensor 60 according to the embodiment includes the above-described detection main body 61, two

harnesses

62 and 63 extending from the detection main body 61 toward the DPF, and an inlet-side sensor 64 provided at the distal end of the left harness 62. And an outlet-side sensing body 65 provided at the tip of the right harness 63. The inlet side sensing body 64 on the left harness 62 side is inserted and attached to the sensor connection plug 10 on the inlet side of the DPF 1 (the part of the exhaust gas inflow space 11 in the catalyst inner case 4 and the catalyst outer case 5). The outlet side sensing element 65 on the right harness 63 side is inserted and attached to the sensor connection plug 44 on the outlet side of the DPF 1 (the filter inner case 20 and the filter outer case 21).

As shown in FIGS. 6 and 7, the longitudinal intermediate portions of the

harnesses

62 and 63 are supported by the plate member 53. In the embodiment, the midway portions of the

harnesses

62 and 63 are placed on the long main body 54 while being clamped by the clamp body 66, and the clamp body 66 is fastened to the long main body 54 with bolts 67. Thus, it is firmly fixed to the long main body 54. In this way, by supporting the midway portions of the two

harnesses

62 and 63 on the base (long body 54) of the plate member 53 at a position appropriately separated from the outer surface of the DPF 1 (catalyst outer case 5 or the like), both The distance between the

harnesses

62 and 63 and the outer surface of the DPF 1 (catalyst outer case 5 or the like) is set to be large. In other words, both the

harnesses

62 and 63 are set so as not to contact the outer surface of the DPF 1 (catalyst outer case 5 or the like).

The exhaust pressure detection means is not limited to the differential pressure sensor 60, and may be an exhaust pressure sensor that detects the pressure on the upstream side of the soot filter 3 in the DPF 1. In this case, there is only one harness with a sensing body, and the midway portion of the single harness may be supported by the plate member. When the exhaust pressure sensor is employed, the pressure (reference pressure) on the upstream side of the soot filter 3 when no soot is deposited on the soot filter 3 is compared with the current pressure detected by the exhaust pressure sensor. Thus, the clogged state of the soot filter 3 is determined.

As apparent from the above configuration, since the detection main body 61 of the differential pressure sensor 60 is attached to the outer surface of the diesel engine 70 (head cover 90) via the support bracket 59, the detection main body 61 of the differential pressure sensor 60 is the diesel engine. It will be located away from the engine 70 itself. For this reason, the heat generated by the diesel engine 70 is difficult to be transmitted to the detection main body 61, and the detection main body 61 can be prevented from malfunctioning due to overheating while the detection main body 61 is assembled to the diesel engine 70.

The sensing

bodies

64 and 65 provided at the distal ends of both the

harnesses

62 and 63 extending from the detection main body 61 are attached to the DPF 1 so that the distance between the outer surface of the DPF 1 and the

harnesses

62 and 63 is increased. In addition, since the longitudinally midway portions of the

harnesses

62 and 63 are supported by the plate member 53 provided on the outer surface side of the DPF 1, the vibrations of the

harnesses

62 and 63 due to the vibration of the diesel engine 70 can be suppressed. For this reason, the looseness and detachment of both the

harnesses

62 and 63 and the

sensing bodies

64 and 65 can be prevented, and the detection by the differential pressure sensor 60 can be performed normally. In addition, since the space between the outer surface of the DPF 1 and the two

harnesses

62 and 63 is increased due to the presence of the plate member 53, the adverse effect of the heat generated by the DPF 1 hardly reaches both the

harnesses

62 and 63. Therefore, there is an effect of suppressing damage to both

harnesses

62 and 63 due to overheating.

Further, on the flywheel housing 78 provided on one side of the diesel engine 70, the DPF 1 is provided in the vicinity of the cylinder head 72 at the top of the diesel engine 70, and is supported by the cylinder head 72. Since the bracket 59 is attached so as to protrude upward, and the detection main body 61 is attached to the upper part of the support bracket 59, the detection main body 61 is separated from the upper surface of the head cover 90 that covers the upper surface of the cylinder head 72. The effect of suppressing damage to the detection main body 61 due to overheating is high. In addition, since the DPF 1 and the differential pressure sensor 60 are close to each other, the lengths of the two

harnesses

62 and 63 that connect the DPF 1 and the detection main body 61 can be set short, so that the assembly workability can be improved and the cost can be reduced. It is.

Next, the detailed structure of the EGR cooler 147 and the cooling water distribution system around the EGR cooler 147 will be described with reference to FIGS. 4, 6 and 8 to 12.

As shown in FIGS. 4 and 9 to 12, an EGR cooler 147 that cools EGR gas using the cooling water of the diesel engine 70 as a refrigerant is disposed below the exhaust manifold 71 on the left side surface of the cylinder block 75. Yes. The EGR cooler 147 has a known structure including a cylindrical outer case 165 and a plurality of heat exchange tubes 166 (see FIG. 12) provided in the outer case 165. Sites near both ends inside the outer case 165 are partitioned by a cutout plate 167. Each heat exchange tube 166 is disposed between both the punched plates 167 so as to communicate with each other through respective punch holes. Accordingly, the internal space of each heat exchange tube 166 communicates with the EGR gas inlet 168 and outlet 169 of the EGR cooler 147 (outer case 165).

The area between both the cutout plates 167 inside the outer case 165 is a sealed space. A cooling water inlet portion 170 and a cooling water outlet portion 171 are provided in a portion of the outer case 165 between both the cutout plates 167. By filling the periphery of each heat exchange tube 166 with the cooling water supplied from the cooling water inlet 170 to the sealed space of the outer case 165, the EGR gas flowing through each heat exchange tube 166 is heat-exchanged, The EGR gas temperature decreases. As a result, the combustion temperature is kept low while suppressing the generation of black smoke (smoke) during combustion, and the effect of reducing the amount of NOx in the exhaust gas is enhanced. The cooling water supplied to the sealed space of the outer case 165 is discharged from the cooling water outlet 171.

As shown in detail in FIG. 9, a cooling water flow path 172 from the cooling water pump 159 to the EGR cooler 147 and the exhaust throttle device 86 is provided on the left side of the diesel engine 70 (exhaust manifold side). The cooling water from the cooling water pump 159 is configured not only to be supplied to the water cooling jacket of the diesel engine 70 but also to send a part thereof to the cooling water flow path 172. That is, the cooling water flow path 172 is configured as a separate system from the cooling water system (path toward the water cooling jacket) to the diesel engine 70 itself.

In this case, the EGR cooler 147 and the exhaust throttle device 86 are connected in series in the cooling water flow path 172. In the cooling water flow path 172, the EGR cooler 147 is positioned upstream of the exhaust throttle device 86 and closer to the cooling water pump 159. That is, the cooling water discharge part 173 protruding from the cooling water pump 159 toward the alternator 161 is connected to the cooling water inlet part 170 of the EGR cooler 147 through the feed pipe 174. The cooling water outlet 171 of the EGR cooler 147 is connected to the cooling water inlet of the exhaust throttle device 86 via a relay pipe 175. The cooling water outlet 88 of the exhaust throttle device 86 is connected to the thermostat case 161 through a return pipe 176. Accordingly, a part of the cooling water from the cooling water pump 159 is supplied and circulated in the order of the EGR cooler 147 → the exhaust throttle device 86 → the thermostat case 160.

As shown in FIGS. 10 to 12, the EGR gas inlet 168 of the outer case 165 in the EGR cooler 147 is connected to the lower surface side of the exhaust manifold 71 via a cylindrical EGR gas take-out pipe 177. In the embodiment, the EGR gas inlet portion 168 of the outer case 165 is bolted to the lower flange portion of the EGR gas extraction pipe 177. The upper flange portion of the EGR gas take-out pipe 177 is bolted to a downward opening formed on the lower surface side of the exhaust manifold 71.

The EGR gas outlet 169 of the outer case 165 in the EGR cooler 147 is connected to a support member 180 attached to the cylinder block 75. In this way, the EGR cooler 147 is supported by the EGR gas take-out pipe 177 and the support member 180 by supporting the longitudinal end portions (EGR gas inlet portion 168 and outlet portion 169) of the EGR cooler 147 so that the cylinder block 75 (specifically Is appropriately separated from the left side surface (see FIGS. 10 and 12).

As shown in FIGS. 8 and 17, a gap SP is provided between the cylinder block 75 and the alternator 161 in the front side view (front view) of the diesel engine 70. The EGR cooler 147 is located beyond the gap SP (the EGR cooler 147 faces the gap SP). Therefore, the cooling air from the cooling fan 76 blows through the gap SP between the left side surface of the cylinder block 75 and the EGR cooler 147 (see FIGS. 9, 18 and 19). For this reason, the transfer of heat from the cylinder block 75 to the EGR cooler 147 is suppressed, and the cooling efficiency of the EGR cooler 147 by the cooling air is also increased.

The support member 180 is integrally provided with a nut portion 181 into which the mounting bolt 184 is inserted, and a cylindrical portion 182 having an exhaust gas outlet pipe line 183 that allows the EGR cooler 147 and the recirculated exhaust gas pipe 148 to communicate with each other. Is. The support member 180 of the embodiment is made of a material such as aluminum that is resistant to rust and corrosion. A support member 180 is detachably fastened to the left side surface of the cylinder block 75 with a mounting bolt 184 inserted into the nut portion 181.

The base side of the cylindrical portion 182 in the support member 180 is connected to the EGR gas outlet 169 of the outer case 165 in the EGR cooler 147 from the lateral side. The upper side of the cylindrical portion 183 is connected in communication with the outlet side of the recirculation exhaust gas pipe 148. Therefore, the EGR gas outlet 169 of the outer case 165 communicates with the recirculated exhaust gas pipe 148 via the EGR gas discharge pipe 183 in the cylindrical part 182. The EGR gas appropriately cooled after passing through the EGR cooler 147 is sent from the EGR gas outlet 169 to the recirculation exhaust gas pipe 148 via the EGR gas discharge pipe 183 in the cylindrical part 182, and to the intake manifold 73 side. Supplied.

In the embodiment, a communication hole 185 that connects the EGR gas outlet 169 and the EGR gas discharge pipe 183 is formed in the middle of the cylindrical portion 182 near the root (see FIG. 12). That is, the EGR gas discharge pipe 183 extends further to the far side than the position of the communication hole 185. The height position of the bottom portion on the back side in the EGR gas discharge pipe 183 is lower than the bottom of the communication hole 185. In other words, a step is formed between the bottom portion on the back side in the EGR gas discharge pipe 183 and the bottom of the communication hole 185. The back portion of the EGR gas discharge pipe 183 functions as a condensed water receiving portion 186 for storing condensed water generated along with EGR gas cooling. For this reason, the condensed water generated along with the EGR gas cooling flows into the condensed water receiving portion 186 and is difficult to be discharged to the recirculation exhaust gas pipe 148.

As is apparent from the above configuration, the EGR cooler 147 and the exhaust throttle device 86 are disposed on the exhaust manifold 71 side of the diesel engine 70, and the EGR cooler is disposed in the cooling water flow path 172 extending from the cooling water pump 159. 147 and the exhaust throttle device 86 are connected in series, the cooling water supplied to the EGR cooler 147 can be used to cool the exhaust throttle device 86, and the heat balance between the EGR cooler 147 and the exhaust throttle device 86 can be improved. It can be maintained in a good state. In addition, since the EGR cooler 147 and the exhaust throttle device 86 are disposed close to each other, the cooling water flow path 172 can be configured compactly.

Moreover, since the EGR cooler 147 is located upstream of the exhaust throttle device 86 in the cooling water flow path 172, the cold cooling water directly sent from the cooling water pump 159 is ahead of the exhaust throttle device 86. Since it is supplied to the EGR cooler 147, the EGR gas can be efficiently cooled, and the NOx emission reduction effect from the diesel engine 70 can be further improved.

Further, a cooling water pump 159 is disposed on the exhaust manifold 71 side of the diesel engine 70, and a cooling water flow path 172 to the EGR cooler 147 and the exhaust throttle device 86 is connected to a cooling water system (water cooling jacket) to the diesel engine 70 itself. Since it is configured in a separate system from the route to which the air travels, the cooling water that has reached a high temperature after contributing to the cooling of the diesel engine 70 (the temperature has increased) is supplied to the EGR cooler 147 and the exhaust throttle device 86 side. There is nothing. Therefore, the trouble accompanying the temperature rise of the cooling water can be prevented, and in particular, the cooling performance of the EGR cooler 147 can be improved.

In addition, since the cooling water flow path 172 is provided on the exhaust manifold 71 side of the diesel engine 70, the cooling water flow path 172 for the EGR cooler 147 and the exhaust throttle device 86 is on the exhaust manifold 71 side where these 147 and 86 are located. I will come together. Accordingly, the cooling water flow path 172 can be easily routed, which can contribute to an improvement in assembly workability.

In the embodiment, an EGR cooler 147 for cooling the EGR gas is disposed in the recirculation exhaust gas pipe 148 that connects the exhaust manifold 71 and the intake manifold 73, and the EGR gas inlet side of the EGR cooler 147 has an EGR gas. While being connected to the exhaust manifold 71 through an extraction pipe 177, the gas outlet side of the EGR cooler 147 is connected to a support member 180 attached to the diesel engine 70, and the EGR cooler 147 is connected to the EGR gas extraction. The pipe 177 and the support member 180 are appropriately separated from the outer surface of the diesel engine 70. For this reason, the heat generated by the diesel engine 70 is difficult to be transmitted to the EGR cooler 147. Therefore, damage to the EGR cooler 147 due to overheating can be suppressed.

In particular, in the embodiment, in the front side view (front view) of the diesel engine 70, a gap SP is provided between the cylinder block 75 and the alternator 161, and the EGR cooler 147 is located beyond the gap SP. Therefore, the cooling air from the cooling fan 76 passes through the gap SP and blows between the left side surface of the cylinder block 75 and the EGR cooler 147. For this reason, the transfer of heat from the cylinder block 75 to the EGR cooler 147 is further suppressed, and the cooling efficiency of the EGR cooler 147 by the cooling air is high.

The support member 180 is formed with an EGR gas discharge pipe 183 that allows the EGR cooler 147 and the recirculation exhaust gas pipe 148 to communicate with each other. Therefore, the support member 180 that supports the EGR cooler 147 is connected to the EGR gas flow path. This can be used as a part of the EGR device 91 and can contribute to a reduction in the number of parts related to the EGR device 91.

Furthermore, a condensate receiving portion 186 for storing condensate generated with the cooling of the EGR gas is formed in the EGR gas discharge pipe 183 of the support member 180, which causes rust, corrosion, and the like. By condensing the condensed water in the condensed water receiving portion 186 in the EGR gas discharge pipe 183, it is possible to suppress the condensed water from being discharged to the intake manifold 73 or the EGR cooler 147, and these

members

73, 147 It can prevent rusting and corrosion. In addition to this, it is also possible to avoid the possibility that condensed water oozes from the mating surface between the EGR cooler 147 and the support member 180.

(6). Diesel Engine Mounting Structure on Backhoe A structure in which the diesel engine 70 shown in FIGS. 4 to 12 is mounted on the backhoe 100 will be described with reference to FIGS. 13 and 14. As shown in FIGS. 13 and 14, the backhoe 100 includes a crawler-type traveling device 102 having a pair of left and right traveling crawlers 103, and a revolving machine body 104 provided on the traveling device 102. The revolving machine body 104 is configured to be horizontally revolved over 360 ° in all directions by a revolving hydraulic motor (not shown). An earthwork plate 105 for ground work is mounted on the rear part of the traveling device 102 so as to be movable up and down. A steering unit 106 and a diesel engine 70 are mounted on the left side of the revolving machine body 104. A working unit 110 having a boom 111 and a bucket 113 for excavation work is provided on the right side of the revolving machine body 104.

The control unit 106 is provided with a control seat 108 on which an operator is seated, an operation means for operating the diesel engine 70 and the like, and a lever or switch as an operation means for the working unit 110. A boom cylinder 112 and a bucket cylinder 114 are arranged on a boom 111 which is a component of the working unit 110. A bucket 113 as an attachment for excavation is pivotally attached to the tip end portion of the boom 111 so as to be inserted and rotated. The boom cylinder 112 or the bucket cylinder 114 is operated to perform earthwork work (ground work such as grooving) by the bucket 113.

(7). Structure for Mounting Diesel Engine to Forklift Car A structure for mounting the diesel engine 70 shown in FIGS. 4 to 12 to the forklift car 120 will be described with reference to FIGS. 15 and 16. As shown in FIGS. 15 and 16, the forklift car 120 includes a traveling machine body 124 having a pair of left and right front wheels 122 and a rear wheel 123. The traveling body 124 is equipped with a control unit 125 and a diesel engine 70. The diesel engine 70 is covered from above with a cover body 133, and the control unit 125 is provided on the cover body 133.

A working part 127 having a fork 126 for cargo handling work is provided on the front side of the traveling machine body 124. A counterweight 131 is provided on the rear side of the traveling machine body 124 to balance the weight with the working unit 127. The control unit 125 is provided with a control seat 128 on which an operator is seated, a control handle 129, levers and switches as operation means for the diesel engine 70 and the working unit 127, and the like.

A fork 126 is mounted on the mast 130, which is a component of the working unit 127, so as to be movable up and down. The fork 126 is moved up and down, a pallet (not shown) loaded with a load is placed on the fork 126, the traveling machine body 124 is moved forward and backward, and a cargo handling operation such as transportation of the pallet is performed. Yes.

The diesel engine 70 is arranged such that the flywheel housing 78 is located on the front side of the traveling machine body 124 and the cooling fan 76 is located on the rear side of the traveling machine body 124. That is, the diesel engine 70 is arranged so that the direction of the engine output shaft 74 is along the front-rear direction in which the working unit 127 and the counterweight 131 are arranged. The diesel engine 70 is supported in an anti-vibration manner via an engine leg 97 on an engine mounting chassis 81 constituting the traveling machine body 124. A mission case 132 is connected to the front side of the flywheel housing 78. The power from the diesel engine 70 via the flywheel 79 is appropriately changed in the transmission case 132 and transmitted to the hydraulic drive sources of the front wheels 122, the rear wheels 123, and the forks 126.

A radiator 134 for cooling the engine opposes the cooling fan 76 at a high position near the counterweight 131 between the control seat 128 and the counterweight 131 disposed behind the control seat 128 in the cover body 133. Are arranged as follows. By blowing cooling air to the radiator 134 by the rotation drive of the cooling fan 76, the radiator 134 is air-cooled.

In addition, this invention is not limited to the above-mentioned embodiment, It can be embodied in various aspects. For example, the engine device for mounting a work vehicle according to the present invention is not limited to the backhoe 100 and the forklift car 120 as described above, but various work vehicles such as agricultural machines such as a combine and a tractor, and special work vehicles such as a crane truck. Widely applicable to. 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.

1 DPF (gas purification filter)
53 Plate member 59 Support bracket 60 Differential pressure sensor 61 as exhaust pressure detection means Detection

main body

62, 63

Harness

64, 65 Sensor 70 Diesel engine 71 Exhaust manifold 73 Intake manifold 76 Cooling fan 86 Exhaust throttle device 91 EGR device 148 Reflux pipe Recirculation exhaust gas pipe 159 as a path Cooling water pump 172 Cooling water flow path 177 EGR gas take-out pipe 180 Support member 183 EGR gas discharge pipe 186 Condensate receiving part

Claims

An engine apparatus comprising: a diesel engine having an intake manifold and an exhaust manifold; and an EGR device that recirculates a part of exhaust gas discharged from the exhaust manifold as EGR gas to the intake manifold.
An EGR cooler for cooling EGR gas is disposed in a reflux line connecting the exhaust manifold and the intake manifold, and a gas inlet side of the EGR cooler is connected to the exhaust manifold via an EGR gas take-out pipe. On the other hand, the gas outlet side of the EGR cooler is attached to the diesel engine via a support member, and the EGR cooler is supported by being separated from the outer surface of the diesel engine by the EGR gas take-out pipe and the support member. An engine device characterized by comprising.
2. The engine apparatus according to claim 1, wherein an EGR gas discharge pipe for communicating the EGR cooler and the reflux pipe is formed in the support member.
An exhaust gas purification device for purifying exhaust gas from the diesel engine, and an exhaust pressure detection means for detecting a pressure difference between the inlet side exhaust pressure and the outlet side exhaust pressure of the exhaust gas purification device. The engine device according to claim 1, wherein a detection body of the exhaust pressure detection means is attached to an outer surface of the diesel engine via a support bracket.
A sensing body provided at a distal end of a harness extending from the detection body is attached to the exhaust gas purification device, and the outer surface of the exhaust gas purification device and the harness can be separated from each other on the outer surface side of the exhaust gas purification device. The engine device according to claim 3, wherein the plate member provided is configured to support a longitudinal midway portion of the harness.