Construction machine

Abstract

An exhaust gas aftertreatment device (14) for treating exhaust gas discharged from an engine (10) is provided with a first processing unit (15) connected to the exhaust gas outflow side of an exhaust pipe (11), a second processing unit (16) connected to the exhaust gas outflow side of the first processing unit (15), and a third processing unit (17) connected to the exhaust gas outflow side of the second processing unit (16). A tail pipe (20) is connected to the exhaust gas outflow side of the third processing unit (17), the first processing unit (15) and the second processing unit (16) are arranged in the vertical direction, and the third processing unit (17) is disposed at a height position between the first processing unit (15) and the second processing unit (16).

Description

Construction machinery

[0001] The present disclosure relates to a construction machine such as a hydraulic excavator equipped with an exhaust gas aftertreatment device in an exhaust pipe of an engine.

[0002] Generally, a hydraulic excavator, a typical example of a construction machine, is composed of a self-propelled lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, and a work device rotatably provided on the front side of the upper rotating body. The upper rotating body is equipped with a cab, fuel tank, hydraulic oil tank, etc. on the front side of a rotating frame, and an engine, heat exchanger, hydraulic pump, etc. on the rear side of the rotating frame.

[0003] Hydraulic excavators generally use diesel engines, which emit harmful substances such as particulate matter (PM) and nitrogen oxides (NOx).

[0004] Therefore, hydraulic excavators are equipped with an exhaust gas aftertreatment device that purifies exhaust gas and is connected to the engine exhaust port via an exhaust pipe. This exhaust gas aftertreatment device houses, in a cylindrical case, a PM trapping device with a DPF (Diesel Particulate Filter) that traps particulate matter contained in the exhaust gas, a NOx purification device that purifies nitrogen oxides (NOx) contained in the exhaust gas, a silencer that reduces exhaust noise, and the like.

[0005] Furthermore, in recent years, regulations (exhaust gas regulations) on emissions of particulate matter (PM), nitrogen oxides (NOx), and the like have become stricter, and as a result, exhaust gas aftertreatment devices have become larger in size in order to improve their performance. However, hydraulic pumps and many pipes, hoses, and the like are arranged around the upper rotating body of a hydraulic excavator, particularly around the engine. Therefore, it is difficult to secure space in the upper rotating body to install larger exhaust gas aftertreatment devices.

[0006] For this reason, some hydraulic excavators have an installation space for the exhaust gas aftertreatment device expanded in the vertical direction, i.e., a hydraulic excavator in which a PM trap, a NOx purification device, a silencer, etc. are housed in two separate cases, and these two cases are arranged parallel to each other in the vertical direction (Patent Documents 1 and 2).

[0007] JP 2014-224428 A JP 2022-53252 A

[0008] However, as global warming continues to progress, exhaust gas regulations for diesel engines are becoming stricter, and exhaust gas aftertreatment devices are becoming larger to improve the exhaust gas purification function, which poses a problem of increasing the size of the vehicle body due to the larger size of the exhaust gas aftertreatment devices.

[0009] An object of one embodiment of the present invention is to provide a construction machine that allows an enlarged exhaust gas aftertreatment device to be installed in a small installation space, thereby preventing the vehicle body from becoming larger.

[0010] One embodiment of the present invention is a construction machine comprising an engine, an exhaust gas aftertreatment device connected to the exhaust port of the engine by an exhaust pipe and consisting of a plurality of units for treating exhaust gas discharged from the engine, and a tail pipe connected to the exhaust gas outlet side of the exhaust gas aftertreatment device, wherein the exhaust gas aftertreatment device comprises a first treatment unit connected to the exhaust gas outlet side of the exhaust pipe, a second treatment unit connected to the exhaust gas outlet side of the first treatment unit, and a third treatment unit connected to the exhaust gas outlet side of the second treatment unit, the tail pipe is connected to the exhaust gas outlet side of the third treatment unit, the first treatment unit and the second treatment unit are arranged side by side in the vertical direction, and the third treatment unit is arranged at a height position between the first treatment unit and the second treatment unit.

[0011] According to one embodiment of the present invention, a large-sized exhaust gas aftertreatment device can be installed in a small installation space, and an increase in the size of the vehicle body can be suppressed.

[0012] FIG. 1 is a right side view showing a hydraulic excavator according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the rear part of an upper rotating body taken from the direction of arrows II-II in FIG. 1. FIG. 3 is a perspective view showing the engine and exhaust gas aftertreatment device in FIG. 2. FIG. 4 is a right side view showing the exhaust gas aftertreatment device in FIG. 2. FIG. 4 is a cross-sectional view showing the rear part of an upper rotating body including an exhaust gas aftertreatment device according to a second embodiment of the present invention. FIG. 5 is a perspective view showing the engine and exhaust gas aftertreatment device in FIG. 5. FIG. 5 is a right side view showing the exhaust gas aftertreatment device in FIG. 5. FIG. 6 is a perspective view showing an exhaust gas aftertreatment device according to Comparative Example 1 together with an engine. FIG. 7 is a rear view showing the exhaust gas aftertreatment device according to Comparative Example 1 together with an engine from the rear side. FIG. 8 is a perspective view showing an exhaust gas aftertreatment device according to Comparative Example 2 together with an engine. FIG. 9 is a rear view showing the exhaust gas aftertreatment device according to Comparative Example 2 together with an engine from the rear side.

[0013] Hereinafter, a crawler type hydraulic excavator will be taken as an example of a construction machine according to an embodiment of the present invention and will be described in detail with reference to the accompanying drawings.

[0014] 1 to 4 show a first embodiment of the present invention. In Fig. 1, a hydraulic excavator 1 is comprised of a self-propelled crawler-type undercarriage 2, an upper rotating body 3 rotatably mounted on the undercarriage 2, and a work device 4 rotatably provided on the front side of the upper rotating body 3 for performing work such as excavating earth and sand. The undercarriage 2 and the upper rotating body 3 constitute a vehicle body of the present invention.

[0015] The upper rotating body 3 is composed of a rotating frame 5 that forms a support structure, a counterweight 6 that is attached to the rear end of the rotating frame 5 and balances the weight with the work implement 4, a cab 7 that is attached to the front left side of the rotating frame 5 and in which the operator sits, a building cover 8 that is attached between the counterweight 6 and the cab 7, an engine 10, a heat exchanger 12, a hydraulic pump 13, an exhaust gas aftertreatment device 14, etc., which will be described later.

[0016] As shown in FIG. 2, the swivel frame 5 includes a bottom plate 5A made of a thick steel plate or the like extending in the front-to-rear direction, a left vertical plate 5B and a right vertical plate 5C standing on the bottom plate 5A and extending in the front-to-rear direction at a predetermined interval in the left-to-right direction, a left side frame 5D and a right side frame 5E arranged at an interval outside the left-to-right direction of the left vertical plate 5B and the right vertical plate 5C and extending in the front-to-rear direction, a plurality of left overhanging beams 5F extending to the left from the bottom plate 5A and the left vertical plate 5B and supporting the left side frame 5D at their tips, and a plurality of right overhanging beams 5G (only one of each is shown) extending to the right from the bottom plate 5A and the right vertical plate 5C and supporting the right side frame 5E at their tips.

[0017] The building cover 8 includes a left side panel 8A extending upward from the left side frame 5D, a right side panel 8B extending upward from the right side frame 5E, and a top panel 8C extending in the left-right direction from the upper part of the left side panel 8A to the upper part of the right side panel 8B. The top panel 8C is provided with an insertion hole 8D located directly above a tail pipe 20 (described later). A diffuser 21 (described later) is inserted and attached into this insertion hole 8D.

[0018] The engine compartment 9 is located in front of the counterweight 6 and is formed as a space surrounded by the left side panel 8A, right side panel 8B, and top panel 8C of the building cover 8 and the revolving frame 5. The engine compartment 9 houses an engine 10, an exhaust pipe 11, a heat exchanger 12, a hydraulic pump 13, and an exhaust gas aftertreatment device 14. In the engine compartment 9, for example, cooling air generated by a cooling fan 12B of the heat exchanger 12 flows from the left side to the right side along the engine 10.

[0019] The engine 10 is located in the engine compartment 9 and mounted on the revolving frame 5 in a horizontal position extending in the left-right direction of the upper revolving body 3. An exhaust port 10A (see FIG. 3) formed by the downstream end of an exhaust manifold is provided at the upper front part of the engine 10. An exhaust pipe 11 is connected to this exhaust port 10A. A third processing unit 17 of the exhaust gas aftertreatment device 14 is disposed above the upper part 10B of the engine 10.

[0020] The exhaust pipe 11 connects the engine 10 and the exhaust gas after-treatment device 14. More specifically, the upstream end of the exhaust pipe 11 is connected to an exhaust port 10A of the engine 10. The downstream side of the exhaust pipe 11 extends diagonally upward to the right, and the downstream end of the exhaust pipe 11 is connected to an inlet 15B of a first treatment unit 15 that constitutes the exhaust gas after-treatment device 14.

[0021] The heat exchanger 12 is located on the revolving frame 5 on the left side of the engine compartment 9. The heat exchanger 12 includes a heat exchanger 12A, such as a radiator for cooling engine coolant or an oil cooler for cooling hydraulic oil, and a cooling fan 12B provided on the right side of the heat exchanger 12A so as to face the heat exchanger 12A. The cooling fan 12B is powered by the rotation of the output shaft of the engine 10 or by the rotation of an electric, hydraulic, or other motor. When the cooling fan 12B is driven, the heat exchanger 12 can circulate cooling air from the left side to the right side of the engine compartment 9.

[0022] The hydraulic pump 13 is provided on the right side of the engine 10. When driven by the engine 10, the hydraulic pump 13 discharges hydraulic oil as pressurized oil toward a control valve device (not shown).

[0023] Next, the exhaust gas aftertreatment device 14 that treats the exhaust gas discharged from the engine 10 will be described.

[0024] The exhaust gas aftertreatment device 14 is disposed on the upper right side of the engine 10 and is connected to an exhaust port 10A of the engine 10 by an exhaust pipe 11. The exhaust gas aftertreatment device 14 treats the exhaust gas discharged from the engine 10. The exhaust gas aftertreatment device 14 is configured to include a first treatment unit 15, a second treatment unit 16, a third treatment unit 17, a first connecting pipe 18, a second connecting pipe 19, and a tail pipe 20, which will be described later.

[0025] The exhaust gas aftertreatment device 14 is equipped with a PM trapping device having a DPF (Diesel Particulate Filter) that traps particulate matter (PM) contained in the exhaust gas emitted from the engine 10, a NOx purification device that purifies nitrogen oxides (NOx) contained in the exhaust gas using a urea aqueous solution, a silencer that reduces exhaust noise, and other treatment devices. These PM trapping device, NOx purification device, silencer, etc. are housed in a first treatment unit 15, a second treatment unit 16, and a third treatment unit 17.

[0026] The first processing unit 15 is disposed on the right side of the upper portion 10B of the engine 10 (above the hydraulic pump 13). The first processing unit 15 includes a case 15A made of a cylindrical container extending in the front-to-rear direction. Part of the processing equipment is housed inside this case 15A.

[0027] As shown in Fig. 3, the case 15A has an inlet section 15B on the front side, which is the exhaust port 10A side of the engine 10, and an outlet section 15C on the rear side. The inlet section 15B is connected to the downstream end of the exhaust pipe 11, which is the exhaust gas outlet side, and is located on the left side of the case 15A. On the other hand, as shown in Fig. 4, the outlet section 15C is connected to the upstream end (lower end) of the first connecting pipe 18, which extends in the vertical direction, which is the exhaust gas inlet side, and is located on the upper side of the case 15A.

[0028] The second processing unit 16 is connected to the exhaust gas outlet side of the first processing unit 15. The second processing unit 16 has a case 16A made of a cylindrical container extending in the front-to-rear direction, similar to the first processing unit 15. A part of the processing device is housed inside this case 16A.

[0029] Furthermore, case 16A is disposed above, and spaced from, case 15A of first processing unit 15. From another perspective, second processing unit 16 is disposed between first processing unit 15 and top panel 8C of building cover 8. As a result, first processing unit 15 and second processing unit 16 are disposed side by side in the vertical direction.

[0030] The case 16A has an inlet section 16B on the rear side so as to face in the vertical direction the outlet section 15C located on the rear side of the first processing unit 15. The inlet section 16B is connected to the downstream end (upper end) of the first connecting pipe 18 extending in the vertical direction, which is the exhaust gas outlet side, and is located below the case 16A.

[0031] Meanwhile, the case 16A has an outlet portion 16C on the front side opposite the inlet portion 16B. The outlet portion 16C is connected to the exhaust gas inlet side of a second connecting pipe 19 extending downward, and is disposed below the case 16A.

[0032] Furthermore, a gap slightly larger than the diameter of the second connecting pipe 19 is formed between the case 16A of the second processing unit 16 and the case 15A of the first processing unit 15. In this configuration, the second connecting pipe 19 can be freely routed between the second processing unit 16 and the first processing unit 15, and the height position of the second processing unit 16 can be kept low.

[0033] The third treatment unit 17 is connected to the exhaust gas outlet side of the second treatment unit 16. The third treatment unit 17 has a case 17A made of a cylindrical container extending in the front-rear direction, similar to the first treatment unit 15 and the second treatment unit 16. Part of the treatment device is housed inside this case 17A.

[0034] Furthermore, case 17A is disposed to the left of, and spaced apart from, case 15A of first processing unit 15 and case 16A of second processing unit 16. In other words, with respect to the cooling air flowing from left to right through engine compartment 9, third processing unit 17 is disposed upstream of first processing unit 15 and second processing unit 16 in the direction of cooling air flowing through engine compartment 9. In addition, third processing unit 17 is disposed at a height position between first processing unit 15 (case 15A) and second processing unit 16 (case 16A).

[0035] As a result, the third processing unit 17, the first processing unit 15, and the second processing unit 16 are arranged so that they extend horizontally (in the front-to-rear direction) and are parallel to each other. Furthermore, the case 17A of the third processing unit 17 is arranged at a lower position than the case 16A of the second processing unit 16. In other words, the distance between the case 17A and the top panel 8C of the building cover 8 can be ensured to be greater than the distance between the case 16A and the top panel 8C of the building cover 8. As a result, the tail pipe 20 and the diffuser 21, which become hot due to exhaust gas, can be arranged in the engine compartment 9, where cooling air flows, by utilizing the large distance between the case 17A and the top panel 8C of the building cover 8.

[0036] The case 17A has an inlet portion 17B at the rear side thereof. The inlet portion 17B is connected to the downstream end (front end) of a second connecting pipe 19 extending forward, and is disposed at the rear side of the case 17A.

[0037] Meanwhile, the case 17A has an outlet portion 17C at the front side opposite to the inlet portion 17B. The outlet portion 17C is connected to a tail pipe 20 extending upward and is disposed above the case 17A.

[0038] Furthermore, as described above, the third treatment unit 17 is disposed upstream of the first treatment unit 15 and the second treatment unit 16 in the direction of the cooling air flowing through the engine compartment 9. Therefore, the cooling air flowing from left to right through the engine compartment 9 hits the third treatment unit 17, then splits into upper and lower airflows and hits the first treatment unit 15 and the second treatment unit 16. With this configuration, the first treatment unit 15, the second treatment unit 16, and the third treatment unit 17 can all be cooled by the cooling air.

[0039] Moreover, more than half of the third processing unit 17 in the vertical direction, specifically the entire third processing unit 17, is located above the upper part 10B of the engine 10. Therefore, the cooling air flowing through the engine compartment 9 can be actively applied to the entire third processing unit 17. With this configuration, the temperatures of the exhaust gas discharged from the third processing unit 17 and the diffuser 21 protruding to the outside can be lowered.

[0040] Furthermore, the third processing unit 17, which is disposed to the left of the first processing unit 15 and the second processing unit 16, is disposed away from the right side panel 8B of the building cover 8 together with the tail pipe 20 and the diffuser 21, which discharge high-temperature exhaust gas and become hot themselves. With this configuration, interference with the diffuser 21, which becomes hot, can be suppressed, and high-temperature countermeasures taken for the tail pipe 20 and the diffuser 21 can be simplified.

[0041] Here, the first processing unit 15, the second processing unit 16, and the third processing unit 17 are provided with cylindrical cases 15A, 16A, and 17A, respectively. Therefore, in a configuration in which the case 15A of the first processing unit 15 and the case 16A of the second processing unit 16 are aligned vertically and the case 17A of the third processing unit 17 is disposed at a height position between the first processing unit 15 (case 15A) and the second processing unit 16 (case 16A), a space is formed between the case 15A, the case 16A, and the case 17A. In this embodiment, this space can be used as installation space for sensors, wiring, etc. provided around the case 17A of the third processing unit 17, and as work space for attaching and detaching these.

[0042] The first connecting pipe 18 connects the first processing unit 15 and the second processing unit 16. The first connecting pipe 18 is disposed on the rear side, opposite the exhaust pipe 11 in the front-to-rear direction. The first connecting pipe 18 is a passage for supplying the exhaust gas that has flowed through the first processing unit 15 to the second processing unit 16, which is the next stage.

[0043] The first connecting pipe 18 is made of a short pipe (cylinder) extending in the vertical direction, and its lower upstream portion is connected to the outlet 15C of the first processing unit 15. The upper downstream portion of the first connecting pipe 18 is connected to the inlet 16B of the second processing unit 16.

[0044] The second connecting pipe 19 connects the second treatment unit 16 and the third treatment unit 17. The second connecting pipe 19 extends in the front-to-rear direction while being slightly inclined left-to-right in order to connect the outlet portion 16C located on the front side of the second treatment unit 16 with the inlet portion 17B located on the rear side of the third treatment unit 17. The second connecting pipe 19 is a passage for supplying exhaust gas that has flowed through the second treatment unit 16 to the third treatment unit 17, which is the next stage. In addition, the inclined second connecting pipe 19 can avoid the first connecting pipe 18 to the left.

[0045] The second connecting pipe 19 is made of a long pipe (cylinder) extending in the front-to-rear direction, and its front portion on the upstream side is bent upward to connect to the outlet 16C of the second processing unit 16. In addition, the second connecting pipe 19 has its rear portion on the downstream side bent forward to connect to the inlet 17B of the third processing unit 17.

[0046] The downstream side of the second connecting pipe 19 is extended to the rear side of the third processing unit 17, so that the tail pipe 20 can be disposed in front of the third processing unit 17. This allows the tail pipe 20 to be disposed toward the center of the upper rotating body 3, thereby suppressing interference with the diffuser 21, which becomes hot.

[0047] The tail pipe 20 is connected to the exhaust gas outlet side of the exhaust gas aftertreatment device 14. Specifically, the tail pipe 20 is made of a short pipe (cylinder) extending in the vertical direction, and is connected to the outlet section 17C located on the exhaust gas outlet side of the third treatment unit 17. Furthermore, since the entire tail pipe 20 is disposed in the engine compartment 9, the exhaust gas flowing into the tail pipe 20 can be cooled by the cooling air flowing through the engine compartment 9.

[0048] 2, the diffuser 21 is provided on the upper panel 8C of the building cover 8. The diffuser 21 guides the exhaust gas discharged from the tail pipe 20 to the outside of the engine compartment 9. The diffuser 21 is inserted into the insertion hole 8D of the building cover 8 and is composed of a pipe section 21A whose portion above the upper panel 8C is bent obliquely rearward and opens, and a flange section 21B which is provided in the vertical middle section of the pipe section 21A with an expanded diameter and attached to the upper panel 8C.

[0049] Here, the exhaust gas discharged from the tail pipe 20 is cooled by the cooling air flowing through the engine compartment 9 as it flows through the tail pipe 20. This makes it possible to suppress a temperature rise in the diffuser 21 due to the exhaust gas flowing through it. Furthermore, because the third processing unit 17 is located at a lower position than the second processing unit 16, most of the pipe section 21A of the diffuser 21 (the lower half) is located in the engine compartment 9. Therefore, the cooling air flowing through the engine compartment 9 can be applied to a wide area of ​​the pipe section 21A of the diffuser 21. This makes it possible to lower the temperature of the diffuser 21.

[0050] The flow of exhaust gas through the exhaust pipe 11, exhaust gas aftertreatment device 14, tail pipe 20, and diffuser 21 thus configured will be described with reference to FIG.

[0051] Exhaust gas emitted from the engine 10 flows through the exhaust pipe 11 into the inlet 15B of the first processing unit 15 as shown by arrow A, and then flows rearward within the case 15A of the first processing unit 15 as shown by arrow B. The exhaust gas that flows through the case 15A to the outlet 15C on the rear side flows upward within the first connecting pipe 18 as shown by arrow C, and flows into the inlet 16B of the second processing unit 16.

[0052] The exhaust gas that has flowed into inlet portion 16B flows forward inside case 16A of second processing unit 16 as shown by arrow D, and flows out into second connecting pipe 19 at outlet portion 16C as shown by arrow E. The exhaust gas that has flowed out into second connecting pipe 19 flows rearward inside second connecting pipe 19 and flows into inlet portion 17B of third processing unit 17.

[0053] The exhaust gas that has flowed into the inlet 17B flows forward within the case 17A of the third processing unit 17, as indicated by arrow F. After flowing forward within the case 17A and reaching the outlet 17C, the exhaust gas flows upward within the tail pipe 20, as indicated by arrow G, and is discharged to the outside through the diffuser 21.

[0054] The hydraulic excavator 1 according to this embodiment has the above-described configuration, and its operation will now be described.

[0055] First, the operator gets into the cab 7 and starts the engine 10. Then, the operator operates a travel control lever (not shown) arranged inside the cab 7 to travel the hydraulic excavator 1. The operator also operates a work control lever (not shown) to perform work such as excavating earth and sand using the work implement 4.

[0056] When the engine 10 is running, exhaust gas emitted from the engine 10 is introduced into the exhaust gas aftertreatment device 14 through the exhaust pipe 11 from the exhaust port 10A. The exhaust gas introduced into the exhaust gas aftertreatment device 14 is then discharged into the atmosphere through the tail pipe 20 and the diffuser 21.

[0057] In this case, carbon monoxide (CO), hydrocarbons (HC), and the like contained in the exhaust gas are oxidized and removed by an oxidation catalyst provided in the exhaust gas aftertreatment device 14. Furthermore, particulate matter (PM) is also burned and removed as necessary. Furthermore, in the exhaust gas aftertreatment device 14, urea water is injected toward the exhaust gas from a urea water injection nozzle, and nitrogen oxides are decomposed into nitrogen and water by a selective reduction catalyst (neither of which is shown). Furthermore, the exhaust gas aftertreatment device 14 can emit sufficiently purified exhaust gas into the atmosphere by oxidizing residual ammonia with the oxidation catalyst and separating it into nitrogen and water.

[0058] Incidentally, exhaust gas regulations for diesel engines are becoming stricter in response to global warming. As a result, exhaust gas aftertreatment devices are becoming larger to improve the exhaust gas purification function. As such, larger exhaust gas aftertreatment devices result in larger hydraulic excavator bodies.

[0059] Therefore, in this embodiment, the exhaust gas aftertreatment device 14 that processes the exhaust gas emitted from the engine 10 comprises a first treatment unit 15 connected to the exhaust gas outlet side of the exhaust pipe 11, a second treatment unit 16 connected to the exhaust gas outlet side of the first treatment unit 15, and a third treatment unit 17 connected to the exhaust gas outlet side of the second treatment unit 16, and the tail pipe 20 is connected to the exhaust gas outlet side of the third treatment unit 17, the first treatment unit 15 and the second treatment unit 16 are arranged side by side in the vertical direction, and the third treatment unit 17 is arranged at a height position between the first treatment unit 15 and the second treatment unit 16.

[0060] Therefore, the exhaust gas aftertreatment device 14 includes three units, the first treatment unit 15, the second treatment unit 16, and the third treatment unit 17, so that it is possible to secure a large amount of space for accommodating an oxidation catalyst, a selective reduction catalyst, etc. Furthermore, the third treatment unit 17 can be placed at a lower position than the second treatment unit 16, so that the installation space in the vertical direction can also be reduced.

[0061] As a result, the exhaust gas aftertreatment device 14 can be installed in a small installation space even if the oxidation catalyst, selective reduction catalyst, etc. are enlarged, thereby preventing the vehicle body (upper rotating body 3) from becoming larger.

[0062] 8 and 9 show an exhaust gas after-treatment device 41 according to a first comparative example, and FIGS. 10 and 11 show an exhaust gas after-treatment device 51 according to a second comparative example.

[0063] 8 and 9, an exhaust gas aftertreatment device 41 according to Comparative Example 1 includes a first treatment unit 42, a second treatment unit 43, and a third treatment unit 44. In the exhaust gas aftertreatment device 41, the second treatment unit 43 is disposed on the upper side and the third treatment unit 44 is disposed on the lower side, so that the second treatment unit 43 and the third treatment unit 44 are arranged side by side in the vertical direction. The first treatment unit 42 is disposed at a height position between the second treatment unit 43 and the third treatment unit 44.

[0064] In the arrangement of the first processing unit 42, the second processing unit 43, and the third processing unit 44 according to Comparative Example 1, the tail pipe 45 extending from the third processing unit 44 becomes long. Therefore, in order to increase the strength of the third processing unit 44 and the tail pipe 45, it is necessary to increase the plate thickness and add a support structure for the tail pipe 45, which results in a complex structure. Furthermore, the tail pipe 45 must be bent in an L-shape to avoid the second processing unit 43 above, which also complicates the structure.

[0065] 10 and 11 , an exhaust gas aftertreatment device 51 according to Comparative Example 2 includes a first treatment unit 52, a second treatment unit 53, and a third treatment unit 54. In the exhaust gas aftertreatment device 51, the third treatment unit 54 is disposed on the upper side and the second treatment unit 53 is disposed on the lower side, so that the second treatment unit 53 and the third treatment unit 54 are disposed side by side in the vertical direction. The first treatment unit 52 is disposed at a height position between the second treatment unit 53 and the third treatment unit 54.

[0066] In the arrangement of the first processing unit 52, the second processing unit 53, and the third processing unit 54 according to this comparative example 2, in order to keep the height dimension low, it is necessary to bend the tail pipe 55 into an L shape and connect it to the side of the third processing unit 54, which makes the configuration of the tail pipe 55 and the structure for attaching it complex.

[0067] As described above, in Comparative Examples 1 and 2, the configuration and mounting structure of the tail pipes 45, 55 are complex, making it difficult to arrange them in a small installation space and making it impossible to prevent the vehicle body from becoming larger.

[0068] Furthermore, by lowering the third processing unit 17, the entire tail pipe 20 is disposed in the engine bay 9, allowing the exhaust gas flowing into the tail pipe 20 to be cooled by the cooling air flowing through the engine bay 9. The exhaust gas cooled in the tail pipe 20 flows into the diffuser 21, thereby suppressing a temperature rise in the diffuser 21 due to the exhaust gas flowing through the diffuser 21. Furthermore, since most of the pipe section 21A of the diffuser 21 can be disposed in the engine bay 9, the pipe section 21A of the diffuser 21 can be cooled by the cooling air flowing through the engine bay 9. As a result, it is possible to simplify high-temperature countermeasures, such as a cover to prevent contact with the diffuser 21, thereby improving assembly workability and reducing costs.

[0069] Specifically, in a configuration in which the cylindrical case 15A constituting the first processing unit 15 and the cylindrical case 16A constituting the second processing unit 16 are aligned vertically, and the cylindrical case 17A constituting the third processing unit 17 is disposed at a height between the first processing unit 15 (case 15A) and the second processing unit 16 (case 16A), a space is formed between the cases 15A, 16A, and 17A. This space is used as installation space for sensors, wiring, etc. provided around the case 17A of the third processing unit 17, and as work space for attaching and detaching these. This allows the three processing units 15, 16, and 17 to be disposed in the small space between the engine 10, hydraulic pump 13, and the top panel 8C of the building cover 8.

[0070] Furthermore, since the first processing unit 15 to which the exhaust pipe 11 is connected is located on the lower side near the engine 10, the exhaust pipe 11 can be shortened, thereby improving assembly workability and reducing manufacturing costs.

[0071] The upper rotating body 3 houses the engine 10 and the exhaust gas aftertreatment device 14, and has an engine compartment 9 through which cooling air flows along the engine 10, and the third treatment unit 17 is located on the left side, upstream of the first treatment unit 15 and the second treatment unit 16 in the cooling air flowing through the engine compartment 9.

[0072] Therefore, by hitting one third treatment unit 17 and then being split vertically, the cooling air can also hit the first treatment unit 15 and the second treatment unit 16. This allows the entire exhaust gas aftertreatment device 14 to be cooled efficiently. Furthermore, since the tail pipe 20 and the diffuser 21 that discharge exhaust gas to the outside are connected to the third treatment unit 17, which is the first to be hit by the cooling air, the tail pipe 20 and the diffuser 21 can also be actively cooled by the cooling air. As a result, it is possible to simplify high-temperature countermeasures, such as heat insulation materials for peripheral parts of the exhaust gas aftertreatment device 14 and covers that prevent contact with the diffuser 21, thereby improving assembly workability and reducing costs.

[0073] Furthermore, the third processing unit 17 can be disposed away from the right side panel 8B of the building cover 8 together with the tail pipe 20 and diffuser 21, which become hot, thereby minimizing interference with the diffuser 21. As a result, it is possible to simplify high-temperature countermeasures, such as a cover that prevents contact with the diffuser 21, thereby improving assembly workability and reducing costs.

[0074] The first processing unit 15, the second processing unit 16, and the third processing unit 17 are arranged so as to extend horizontally and be parallel to one another. This reduces the space required for installing the three processing units 15, 16, and 17. It also makes it possible to ensure working space for assembly and maintenance.

[0075] Furthermore, more than half of the third processing unit 17 in the vertical direction, in this embodiment, the entire third processing unit 17, is located above the upper portion 10B of the engine 10. This allows the third processing unit 17 to be actively cooled by being exposed to the cooling air flowing through the engine compartment 9.

[0076] Furthermore, by extending the downstream side of the second connecting pipe 19 to the rear side of the third processing unit 17, the tail pipe 20 can be disposed in front of the third processing unit 17. This allows the tail pipe 20 to be disposed toward the center of the upper rotating body 3, thereby suppressing interference with the diffuser 21, which becomes hot.

[0077] 5 to 7 show a second embodiment of the present invention. This embodiment is characterized in that the first processing unit and the second processing unit are arranged vertically, with the first processing unit on the upper side and the second processing unit on the lower side. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0078] 5 and 6, the exhaust pipe 31 according to the second embodiment, like the exhaust pipe 11 according to the first embodiment, connects the engine 10 to an exhaust gas aftertreatment device 32, which will be described later. However, the exhaust pipe 31 according to the second embodiment differs from the exhaust pipe 11 according to the first embodiment in that it is longer than the exhaust pipe 11 according to the first embodiment and has a steeper inclination angle. That is, the upstream end of the exhaust pipe 31 is connected to the exhaust port 10A of the engine 10, and the downstream end is connected to an inlet 33B of a first treatment unit 33, which is disposed at a higher position.

[0079] The exhaust gas aftertreatment device 32 according to the second embodiment is disposed on the upper right side of the engine 10 in order to treat exhaust gas discharged from the engine 10, and is connected to an exhaust port 10A of the engine 10 by an exhaust pipe 31. Similar to the exhaust gas aftertreatment device 14 according to the first embodiment, the exhaust gas aftertreatment device 32 according to the second embodiment is configured to include a first treatment unit 33, a second treatment unit 34, a third treatment unit 35, a first connecting pipe 36, a second connecting pipe 37, and a tail pipe 38, which will be described later.

[0080] However, the exhaust gas aftertreatment device 32 according to the second embodiment differs from the exhaust gas aftertreatment device 14 according to the first embodiment in that the positions of the first treatment unit 33 and the second treatment unit 34 are reversed in the vertical direction.

[0081] The first processing unit 33 according to the second embodiment is located to the right of the engine 10 and disposed below the top panel 8C of the building cover 8. Like the first processing unit 15 according to the first embodiment, the first processing unit 33 has a case 33A, an inlet section 33B, and an outlet section 33C. However, the first processing unit 33 according to the second embodiment differs from the first processing unit 15 according to the first embodiment in that it is disposed above a second processing unit 34, which will be described later.

[0082] The second treatment unit 34 according to the second embodiment is connected to the exhaust gas outlet side of the first treatment unit 33. The second treatment unit 34 has a case 34A, an inlet section 34B, and an outlet section 34C, similar to the second treatment unit 16 according to the first embodiment. However, the second treatment unit 34 according to the second embodiment differs from the second treatment unit 16 according to the first embodiment in that it is disposed below the first treatment unit 33.

[0083] The first processing unit 33 and the second processing unit 34 are arranged side by side in the vertical direction, with the first processing unit 33 on the upper side and the second processing unit 34 on the lower side.

[0084] The third treatment unit 35 according to the second embodiment is connected to the exhaust gas outlet side of the second treatment unit 34. Similar to the third treatment unit 17 according to the first embodiment, the third treatment unit 35 has a case 35A, an inlet portion 35B, and an outlet portion 35C.

[0085] The case 35A is disposed at a height position between the case 33A of the first processing unit 33 and the case 34A of the second processing unit 34. In addition, the case 35A is disposed to the left of the cases 33A and 34A with a gap therebetween.

[0086] 7, the first connecting pipe 36 is located at the rear side and connects the first processing unit 33 and the second processing unit 34. The first connecting pipe 36 is made of a short pipe (cylinder) extending in the vertical direction, and its upper portion on the upstream side is connected to the outlet 33C of the first processing unit 33. Furthermore, the first connecting pipe 36 has its lower portion on the downstream side connected to the inlet 34B of the second processing unit 34.

[0087] The second connecting pipe 37 connects the second processing unit 34 and the third processing unit 35. The second connecting pipe 37 is made of a long pipe (cylinder) extending in the front-to-rear direction, and its front portion, which is on the upstream side, is bent downward to connect to the outlet 34C of the second processing unit 34. In addition, the second connecting pipe 37 has its rear portion, which is on the downstream side, bent forward to connect to the inlet 35B of the third processing unit 35.

[0088] The tail pipe 38 is connected to the exhaust gas outlet side of the exhaust gas aftertreatment device 32. The tail pipe 38 is made of a short pipe (cylinder) extending in the vertical direction, and is connected to the outlet portion 35C of the third treatment unit 35. The upper part of the tail pipe 38 is inserted into the diffuser 21.

[0089] The flow of exhaust gas through the exhaust pipe 31, exhaust gas aftertreatment device 32, and tail pipe 20 thus configured will be described with reference to FIG.

[0090] Exhaust gas emitted from the engine 10 flows through the exhaust pipe 31 into the inlet 33B of the first processing unit 33 as shown by arrow H, and then flows rearward within the case 33A of the first processing unit 33 as shown by arrow J. The exhaust gas that flows through the case 33A to the outlet 33C on the rear side flows downward within the first connecting pipe 36 as shown by arrow K, and flows into the inlet 34B of the second processing unit 34.

[0091] The exhaust gas that has flowed into the inlet 34B flows forward inside the case 34A of the second processing unit 34 as shown by arrow L, and flows out into the second connecting pipe 37 at the outlet 34C as shown by arrow M. The exhaust gas that has flowed out into the second connecting pipe 37 flows rearward inside the second connecting pipe 37 and flows into the inlet 35B of the third processing unit 35.

[0092] The exhaust gas that has flowed into the inlet 35B flows forward within the case 35A of the third processing unit 35, as indicated by arrow N. The exhaust gas that has flowed forward within the case 35A and reached the outlet 35C flows upward within the tail pipe 38, as indicated by arrow P, and is discharged to the outside through the diffuser 21.

[0093] Thus, the second embodiment configured as described above can also achieve the same functions and effects as the first embodiment. In particular, in the second embodiment, the first processing unit 33 to which the exhaust pipe 31 is connected is disposed on the upper side, away from the engine 10, so that the exhaust pipe 31 can be made long. As a result, the long exhaust pipe 31 can absorb the oscillation of the engine 10.

[0094] In the first embodiment, the engine 10 is mounted on the revolving frame 5 in a horizontal position extending in the left-right direction of the upper revolving body 3, and the exhaust gas after-treatment device 14 is disposed on the right side of the engine 10. However, the present invention is not limited to this, and, for example, the exhaust gas after-treatment device may be disposed on the left side of the engine. Also, the engine may be mounted on the revolving frame in a vertical position extending in the front-rear direction of the upper revolving body, and the exhaust gas after-treatment device may be disposed on the front or rear side of the engine. This configuration can be similarly applied to the second embodiment.

[0095] In the first embodiment, the exhaust pipe 11, tail pipe 20, and diffuser 21 are disposed in front of the engine 10. However, the present invention is not limited to this. For example, the exhaust pipe, tail pipe, and diffuser may be disposed in rear of the engine. This configuration can be similarly applied to the second embodiment.

[0096] Furthermore, in each embodiment, the hydraulic excavator 1 equipped with a crawler-type undercarriage 2 has been described as an example of a construction machine. However, the present invention is not limited to this and may be applied to, for example, a hydraulic excavator equipped with a wheel-type undercarriage. In addition, the present invention may be widely applied to other construction machines such as wheel loaders, dump trucks, and hydraulic cranes.

[0097] REFERENCE SIGNS LIST 1 Hydraulic excavator (construction machine) 2 Undercarriage (vehicle body) 3 Upper rotating body (vehicle body) 9 Engine compartment 10 Engine 10A Exhaust port 10B Upper part 11, 31 Exhaust pipe 14, 32 Exhaust gas aftertreatment device 15, 33 First treatment unit 16, 34 Second treatment unit 17, 35 Third treatment unit 20, 38 Tail pipe

Claims

1. The engine and An exhaust gas aftertreatment device, comprising multiple units connected to the exhaust port of the engine by an exhaust pipe, which processes the exhaust gas discharged from the engine, A tailpipe connected to the exhaust gas outlet side of the exhaust gas aftertreatment device, An engine compartment housing the engine and the exhaust gas aftertreatment device, A diffuser is attached to the building cover that partitions the engine compartment and guides the exhaust gas discharged from the tailpipe to the outside of the engine compartment, A cooling fan powered by the rotation of the output shaft of the aforementioned engine, In construction machinery equipped with, The aforementioned exhaust gas aftertreatment device is A first processing unit connected to the exhaust gas outlet side of the exhaust pipe, A second processing unit connected to the exhaust gas outlet side of the first processing unit, A third processing unit connected to the exhaust gas outlet side of the second processing unit, Equipped with, The tailpipe is connected to the exhaust gas outlet side of the third processing unit, The first processing unit and the second processing unit are arranged in a vertically aligned manner. The third processing unit and the tail tube are arranged to fit between the first processing unit and the second processing unit in the vertical direction. The diffuser is inserted through a through hole formed in the building cover and positioned inside the engine compartment. A construction machine characterized in that the third processing unit, the tailpipe, and the portion of the diffuser that enters the engine compartment are positioned upstream of the cooling air generated by the cooling fan flowing through the engine compartment, relative to the first processing unit and the second processing unit.

2. In the construction machine described in claim 1, A construction machine characterized in that the first processing unit, the second processing unit, and the third processing unit are arranged so as to be parallel to each other while extending horizontally.

3. In the construction machine described in claim 1, The construction machine is characterized in that the third processing unit has more than half of its vertical portion located above the top of the engine.