A bulldozer includes a blade, an engine, first and second exhaust treatment devices that treat exhaust from the engine, and an engine cover. The first exhaust treatment device is disposed in front of the engine and lower than a first upper surface of the engine. The second exhaust treatment device is disposed above the engine. The engine cover includes a second upper surface sloping forward and downward. The engine cover covers the engine and the first and second exhaust treatment devices. Longitudinal directions of the first and second exhaust treatment devices extend along a vehicle lateral direction. In a top view of the bulldozer, the second exhaust treatment device includes a portion overlapping the engine. As seen from a side of the bulldozer, a front edge of the second exhaust treatment device is positioned forward of a rear edge of the first exhaust treatment device.

CROSS-REFERENCE OT RELATED APPLICATIONS

This application is a U.S. National stage application of International Application No. PCT/JP2014/067763, filed on Jul. 3, 2014.

BACKGROUND

Field of the Invention

The present invention relates to a bulldozer, which is one type of work vehicle.

Background Information

In Japanese Laid-Open Patent Publication 2005-113674, a bulldozer is disclosed in which the upper surface of the engine cover is sloped forward and also downward (refer to Japanese Laid-Open Patent Publication 2005-113674). With this bulldozer the workability is enhanced, since the operator is able visually to check the upper portion of the blade, i.e. of the working implement.

On the other hand, from the standpoint of protection of the natural environment, a work vehicle such as a bulldozer needs to be equipped with exhaust purification (refer to Publication of U.S. Pat. No. 8,141,535 B2). Therefore, it is nowadays practiced to mount an exhaust treatment device to a work vehicle. The term “exhaust treatment device” means, for example, a diesel particulate filter (DPF) device, a selective catalytic reduction (SCR) device, a diesel oxidation catalyst (DOC) device, or the like. From these various exhaust treatment devices, modern work vehicles need to be provided with either two or more exhaust treatment devices of the same type, or two or more exhaust treatment devices of different types.

SUMMARY

If two or more exhaust treatment devices are disposed above the engine in order for the exhaust treatment devices to be housed in the engine compartment of the bulldozer described above, then it is necessary to raise the upper surface of the engine cover. If the upper surface of the engine cover is raised, then the region visible to the operator on the upper portion of the blade of the working implement becomes restricted, so that the workability is reduced.

Moreover, if these two or more exhaust treatment devices are disposed at the side of the engine, then the lateral width of the engine compartment becomes large, and the regions visible to the operator at the side portions of the blade of the working implement become restricted. Accordingly the workability is reduced with this type of configuration as well.

The aim of the present invention is to provide a bulldozer with which deterioration of the workability is prevented, even though two or more exhaust treatment devices are housed in the engine compartment.

The bulldozer according to a first aspect of the present invention comprises a blade, an engine, a first exhaust treatment device, a second exhaust treatment device, and an engine cover. The first exhaust treatment device and the second exhaust treatment device treat exhaust from the engine. The first exhaust treatment device is disposed in front of the engine and lower than the upper surface of the engine. The second exhaust treatment device is disposed above the engine. The engine cover includes an upper surface sloping forward and downward. The engine cover covers the engine, the first exhaust treatment device, and the second exhaust treatment device. Longitudinal directions of the first exhaust treatment device and the second exhaust treatment device extend along a vehicle lateral direction. As seen from the top of the vehicle, the second exhaust treatment device includes a portion that overlaps the engine. And, as seen from the side of the vehicle, a front edge of the second exhaust treatment device is positioned behind a rear edge of the first exhaust treatment device.

There may be further included a relay connection pipe which connects the first exhaust treatment device and the second exhaust treatment device and which is disposed over the first exhaust treatment device, and. An upper edge of the relay connection pipe may be positioned below an upper edge of the second exhaust treatment device.

The front edge of the second exhaust treatment device may be positioned behind a rear edge of the relay connection pipe.

As seen from the front of the vehicle, the second exhaust treatment device may include a portion that is overlapped over the relay connection pipe.

The second exhaust treatment device may be positioned forward of a center position of the engine in the front and rear direction.

The bulldozer described above may further comprise an air cleaner disposed higher than the engine and lower than the upper surface of the engine cover. The air cleaner may be positioned rearward of a center position of the engine in the front and rear direction.

A front edge of the relay connection pipe may be positioned rearward of the front edge of a first exhaust treatment device.

The engine cover may further include a front surface following along the first exhaust treatment device and the relay connection pipe, and a curved surface connecting the upper surface and the front surface smoothly.

An external diameter of the relay connection pipe may be shorter than an external diameter of the first exhaust treatment device and an external diameter of the second exhaust treatment device.

The bulldozer described above may further comprise a blade drive mechanism driving the blade. When the blade is raised by the blade drive mechanism to the maximum extent, the front surface of the engine cover may be positioned forward of and below a rear edge of the blade drive mechanism.

The bulldozer described above may further comprise a hydraulic pump disposed behind the engine.

The bulldozer described above may further comprise a cab disposed behind the engine and above the hydraulic pump.

An angle between a vertical direction and a straight line that joins a point indicating a central axial line of the first exhaust treatment device and a point indicating a central axial line of the relay connection pipe may be in the range between 0° and 20° inclusive. An angle between the vertical direction and a straight line that joins the point indicating the central axial line of the relay connection pipe and a point indicating a central axial line of the second exhaust treatment device may be in the range between 40° and 70° inclusive. An angle between the vertical direction and a straight line that joins the point indicating the central axial line of the first exhaust treatment device and the point indicating the central axial line of the second exhaust treatment device may be in the range between 10° and 40° inclusive.

The bulldozer described above may further comprise a mounting bracket, a first support bracket, and a second support bracket. The mounting bracket may be attached to the engine. The first support bracket may be attached to the mounting bracket, and may support the first exhaust treatment device. And the second support bracket may be attached to the mounting bracket, and may support the second exhaust treatment device.

The mounting bracket may include a lower attachment portion, an upper attachment portion, and a wall portion. The first support bracket may be attached to the lower attachment portion. The second support bracket may be attached to the upper attachment portion. And the wall portion may extend in the vertical direction from a rear end portion of the lower attachment portion to a front end portion of the upper attachment portion.

The mounting bracket may include a first connection portion, a second connection portion, and a third connection portion. The first connection portion may connect to a lower portion of the engine. The second connection portion may connect to an upper portion of the engine. The third connection portion may connect to an intermediate portion of the engine between the upper portion and the lower portion.

In the bulldozer according to the present invention, the first exhaust treatment device is disposed in front of the engine, while the second exhaust treatment device is disposed above the engine. And the longitudinal directions of the first exhaust treatment device and the second exhaust treatment device extend along the vehicle lateral direction. Moreover, as seen from the side of the vehicle, the front edge of the second exhaust treatment device is positioned behind the rear edge of the first exhaust treatment device. Due to this, even though the engine cover has the upper surface that slopes forward and downward, still it is possible to house the first exhaust treatment device and the second exhaust treatment device in the engine compartment without greatly raising the upper surface. As a result, it is possible to extend the region visible to the operator on the upper portion of the blade of the working implement, so that it is possible to prevent deterioration of the workability.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Overall Structure

A left side view of a bulldozer1according to an embodiment of the present invention is shown inFIG. 1. And a top view illustrating a part of the bulldozer according to the embodiment of the present invention is shown inFIG. 2. InFIG. 2, an engine compartment8is illustrated in a state in which an engine cover13, which will be described hereinafter, has been removed. It should be understood that, in the following explanation, “front and rear direction” means the front and rear direction of the bulldozer1. To put it in other words, the front and rear direction means the front and rear direction as seen by an operator sitting in a cab (an operator compartment)12. Moreover, the left/right direction means the left/right direction as seen by an operator sitting in the cab (the operator compartment). Furthermore, the lateral direction means the direction lateral to the vehicle, i.e. to the bulldozer1; in other words, it means either one of the left direction and right direction described above.

The bulldozer1comprises a travelling unit2, a main vehicle body3, and a working implement4. The travelling unit2is a device for driving the vehicle, and comprises crawler belts11. The bulldozer11propels itself by driving the crawler belts11.

The main vehicle body3comprises a vehicle body frame10(refer toFIG. 2), the cab12, an engine cover13, and a cooling device14(refer toFIG. 1). The engine cover13is disposed in front of the cab12. An engine compartment8(refer toFIG. 2) in which an engine5is housed is positioned within the engine cover13. The upper surface13aof the engine cover13slopes upward towards the rear. The cooling device14is disposed behind the cab12. It should be understood that, generally, with a bulldozer, the cooling device is disposed in front of the engine and within an engine cover that is in front of the cab. The cooling device14may, for example, include a radiator that cools the coolant of the engine5, an oil cooler that cools hydraulic fluid, and a cooling fan that generates a flow of air.

The working implement4is provided in front of the engine cover13. The working implement4includes a blade15and a blade drive mechanism18. The central portion of the upper surface of the blade15protrudes more upward as compared to the left and right end portions thereof, and functions as a spill guard for protecting the hydraulic cylinders that are disposed at the rear side of the blade15. The blade drive mechanism18drives the blade15. The blade drive mechanism18includes hydraulic cylinders16and a blade support frame17. The blade support frame17pivotally supports the blade15. As illustrated inFIG. 2, the hydraulic cylinders16include a first cylinder16a, a second cylinder16b, a third cylinder16c, and a fourth cylinder16d. Both ends of the first cylinder16aare rotatably connected to the blade support frame17. Both ends of the second cylinder16bare rotatably connected to the blade support frame17. A first end of the third cylinder16cis rotatably connected to the blade support frame17. And a second end of the third cylinder16cis connected to the blade15. Moreover, a first end of the fourth cylinder16dis rotatably connected to the blade support frame17. And a second end of the fourth cylinder16dis connected to the blade15. The first cylinder16aand the third cylinder16care disposed on the left side of the engine cover13. And the second cylinder16band the fourth cylinder16dare disposed on the right side of the engine cover13. The first cylinder16aand the second cylinder16bmove the blade15up and down. And the third cylinder16cand the fourth cylinder16dchange the orientation of the blade15. In other words, the first cylinder16athrough the fourth cylinder16dcontrol the position or the orientation of the blade15.

Structures Internal to the Engine Compartment

FIG. 3is a left side view illustrating the internal structure of the engine compartment8inside the engine cover13. AndFIG. 4is a right side view illustrating the internal structure of the engine compartment8inside the engine cover13. The right side ofFIG. 4represents the front of the vehicle. AndFIG. 5is a front view illustrating the internal structure of the engine compartment8inside the engine cover13. It should be understood that, for ease of understanding, inFIGS. 3 and 4, the vehicle body frame10and the engine cover13are illustrated by chain double dashed lines. Moreover, inFIG. 5, the upper edge of the vehicle body frame10and the engine cover13that are adjacent to a mounting bracket50, which will be described hereinafter, are illustrated by chain double dashed lines, and the schematic outline of the engine5is illustrated by dotted lines. Furthermore, inFIGS. 2 through 5, parts of the structures within the engine compartment8are omitted as appropriate. As shown inFIGS. 2 to 4, the main vehicle body3comprises the engine5, a flywheel housing6and a hydraulic pump7. The engine5is disposed within the engine cover13.

The engine5is a diesel engine, and the output of the engine5is controlled by the amount of injection of fuel from a fuel injection pump (not shown in the drawings) being adjusted. The engine5comprises a crankcase22, an oil pan23, a cylinder body24, a cylinder head25, and a cylinder head cover26. Moreover, the engine5includes a crankshaft (not shown in the drawings). The crankshaft extends in the front and rear direction of the vehicle. To put it in other words, the engine5is a so-called longitudinally disposed engine, and is arranged with its longitudinal dimension along the front and rear direction of the vehicle and its short dimension along the lateral direction of the vehicle. Since with this configuration the width of the vehicle can be narrowed, accordingly it is possible to secure visibility for the left and right lower ends of the blade15, as is required for a bulldozer. A×4 inFIGS. 3 and 4denotes the central axial line of the crankshaft. The crankcase22houses the crankshaft. A cam pulley (not shown in the drawings) is disposed in front of the crankcase22. The crankshaft is connected to the cam pulley. As shown inFIGS. 3 and 4, a belt27passes around the cam pulley. The oil pan23is disposed below the crankcase22. And the cylinder body24is disposed above the crankcase22. Moreover, the cylinder head25is disposed above the cylinder body24. And the cylinder head cover26is disposed above the cylinder head25.

Furthermore, the engine5includes a supercharger28. The supercharger28is connected to the cylinder head25via an exhaust conduit of the engine5(not illustrated in the drawings). In the top view of the vehicle, the supercharger28is disposed at the side of the cylinder head25. And, as seen from the side of the vehicle, at least a part of the supercharger28is positioned above the upper surface of the engine5, in other words is positioned higher than the upper surface of the cylinder head cover26.

The flywheel housing6is disposed behind the engine5. And the hydraulic pump7is disposed behind the flywheel housing6, and is attached to the flywheel housing6. In other words, the hydraulic pump7is disposed behind the engine5. The hydraulic pump7is linked to the output shaft of the engine5via the flywheel. The hydraulic pump7is driven to discharge hydraulic fluid by the drive force from the engine5. The cab12is disposed directly above the hydraulic pump7. In other words, the cab12is disposed behind the engine5and also above the hydraulic pump7.

The main vehicle body3includes an air cleaner33and a duct34. The air cleaner33and the duct34are positioned tower than the upper surface13aof the engine cover13. The air cleaner33is disposed over the engine5. The air cleaner33is fixed to the engine cover13. The air cleaner33is cylindrical in shape. The central axial line A×5 of the air cleaner33shown inFIG. 2is disposed approximately horizontally, so as to extend along the vehicle lateral direction. Moreover, the air cleaner33is positioned behind the central position ML of the engine5in the forward and rear direction of the vehicle. Specifically, the central axis A×5 of the air cleaner33is positioned behind the central position ML of the engine5in the vehicle forward and rear direction. The air cleaner33has an intake port (not shown in the drawings) and an exhaust port331(refer toFIGS. 2 and 4). The intake port is connected to a head portion35(refer toFIG. 1) via a pipe member not shown in the figures. The head portion35protrudes upward from the upper surface of the engine cover13. The exhaust pot331is provided on the side of the air cleaner33. The exhaust port331is positioned higher than the supercharger28described above.

The duct34connects the air cleaner33and the engine5. The duct34extends downwards from the exhaust port331of the air cleaner33, and has a shape that is curved towards the supercharger28. As shown inFIG. 4, the duct34includes a first connection portion36, a second connection portion37, and a vibration absorption portion38. The first connection portion36is connected to the engine5. Specifically, the first connection portion36is connected to the supercharger28. The second connection portion37is connected to the air cleaner33. The second connection portion37is connected to the exhaust port331of the air cleaner33. And, in the duct34, the vibration absorption portion38is positioned between the first connection portion36and the second connection portion37. The vibration absorption portion38has the form of a bellows.

Structure of the Exhaust Treatment Devices

The main vehicle body3includes a first exhaust treatment device41, a second exhaust treatment device42, a relay connection pipe43, a first connection pipe45, and a second connection pipe46. The first exhaust treatment device41, the second exhaust treatment device42, and the relay connection pipe43will be collectively referred to as an exhaust treatment assembly40. The first connection pipe45connects the engine5and the first exhaust treatment device41. In more detail, the first connection pipe45connects together the aforementioned supercharger28and the first exhaust treatment device41. And the second connection pipe46connects to the second exhaust treatment device42, and discharges exhaust from the engine5that has been treated by the second exhaust treatment device42. The second connection pipe46is connected to an exhaust pipe47which is illustrated inFIG. 1. The exhaust pipe47is arranged so as to protrude upwards from the engine cover13.

In this embodiment, the first exhaust treatment device may, for example, be a diesel oxidation catalyst (DOC) device, and treats exhaust from the engine5which is fed via the first connection pipe45. By oxidation, the first exhaust treatment device41eliminates hydrocarbons (HC), carbon monoxide (CO), and soluble organic components (SOP) included in the exhaust.

As shown inFIGS. 3 and 4, the first exhaust treatment device41is disposed in front of the engine5, and at the foremost position within the engine cover13. Locating the cooling device14behind the cab12rather than within the engine compartment8enables this type of arrangement. Moreover, the first exhaust treatment device41is disposed lower than the upper surface of the engine5. Specifically, the first exhaust treatment device41is disposed lower than the upper surface of the cylinder head cover26. Also, the first exhaust treatment device41is disposed higher than the bottom surface of the oil pan23.

As shown, inFIGS. 3 to 5, the first exhaust treatment device41has a generally cylindrical external shape. The dimension of the first exhaust treatment device41in the vehicle lateral direction is smaller than that of the engine5in the vehicle lateral direction. Moreover, the dimension of the first exhaust treatment device41in the vehicle lateral direction is smaller than that of the second exhaust treatment device42in the vehicle lateral direction. As shown inFIG. 5, the first exhaust treatment device41is arranged so that its central axial line A×1 extends along the vehicle lateral direction. In other words, the longitudinal direction of the first exhaust treatment device41extends along the vehicle lateral direction. Furthermore, the first exhaust treatment device41includes a part that is overlapped over the engine5, as seen from the front of the vehicle.

As shown inFIGS. 3 to 5, the first exhaust treatment device41includes a first connection port41aand a second connection port41b. As shown inFIGS. 4 and 5, the first connection pipe45is connected to the first connection port41a. And, as shown inFIGS. 3 and 5, the relay connection pipe43is connected to the second connection port41b.

As shown inFIG. 4, the first connection port41aprotrudes obliquely upward. Specifically, the first connection port41aprotrudes upward and moreover obliquely toward the engine5. Correspondingly, the first connection pipe45extends obliquely downward toward the first exhaust treatment device41from the position where it is connected to the engine5. Due to this, the first exhaust treatment device41is disposed at a position such that it does not overlap the engine5in a top view. In other words, at least one of the first exhaust treatment device41and the second exhaust treatment device42is disposed at a position such that it does not overlap the engine5in a top view.

As shown inFIG. 3, the second connection port41bis sloped slightly backward from the vertical direction. Due to this, as shown inFIG. 2, the central axial line A×3 of a straight line portion43b(to be described in detail hereinafter) of the relay connection pipe43is positioned, in a top view, a little behind the central axial line A×1.

The relay connection pipe43connects the first exhaust treatment device41and the second exhaust treatment device42. As shown inFIGS. 3 and 5, the external diameter of the relay connection pipe43is smaller than the external diameter of the first exhaust treatment device41and the external diameter of the second exhaust treatment device42. A first end of the relay connection pipe43is connected to the second connection port41bof the first exhaust treatment device41. And a second end of the relay connection pipe43, which is opposite to the first end of the relay connection pipe43, is connected to a third connection port42aof the second exhaust treatment device42. The relay connection pipe43is disposed in front of the engine5, and moreover above the first exhaust treatment device41. Furthermore, as shown inFIG. 5, as seen from the front of the vehicle, the relay connection pipe43includes a part that is overlapped over the engine5. And, as seen from the front of the vehicle, the relay connection pipe43is overlapped over a part of the first connection pipe45. Moreover, as shown inFIG. 4, the relay connection pipe43passes through a position close to the first connection pipe45.

As shown inFIG. 5, the relay connection pipe43includes a first curved portion43a, a straight line portion43b, and a second curved portion43c. The straight line portion43bis positioned above the first exhaust treatment device41. As shown inFIGS. 2 and 5, the straight line portion43bis arranged so that its central axial line A×3 extends along the vehicle lateral direction. In other words, the straight line portion43bis arranged so that its central axial line A×3 is parallel to the central axial line A×1 of the first exhaust treatment device41. To express this in another way, the longitudinal direction of the relay connection pipe43extends along the vehicle lateral direction. The first curved portion43acouples together the straight line portion43band the second connection port41b. And the second curved portion43ccouples together the straight line portion43band the third connection port42aof the second exhaust treatment device42. An injector44is attached in the first curved portion43a. The injector44injects a reducing agent into the interior of the relay connection pipe43. The reducing agent may, for example, be aqueous urea.

In this embodiment, as an example, the second exhaust treatment device42is a selective catalytic reduction device. The second exhaust treatment device42treats the exhaust from the engine5which has been treated by the first exhaust treatment device41. The second exhaust treatment device42selectively reduces nitrogen oxides (NOx).

The second exhaust treatment device42has a generally cylindrical external shape. As shown inFIGS. 3 through 5, the second exhaust treatment device42is disposed above the engine5. As shown inFIG. 5, the second exhaust treatment device42is arranged so that its central axial line A×2 extends along the vehicle lateral direction. Moreover, the second exhaust treatment device42is arranged so that its central axial line A×2 is parallel to the central axial line A×1 of the first exhaust treatment device41. In other words, the longitudinal direction of the second exhaust treatment device42extends along the vehicle lateral direction. Furthermore, the second exhaust treatment device42is disposed so that the central axial line A×2 of the second exhaust treatment device42is above the upper edge of the relay connection pipe43. In other words, the upper edge of the relay connection pipe43is positioned below the upper edge of the second exhaust treatment device42. Accordingly, the first exhaust treatment device41, the relay connection pipe43, and the second exhaust treatment device42are arranged in a vertical series. Moreover, as seen from the front of the vehicle, the second exhaust treatment device42includes a portion that is overlapped over the relay connection pipe43.

Furthermore, as shown inFIG. 2, the second exhaust treatment device42is arranged so as to overlap a part of the engine5in a top view. In other words, as seen from the top of the vehicle, the second exhaust treatment device42has a part that is overlapped over the engine5. In more detail, as shown inFIGS. 3 and 4, the second exhaust treatment device42is disposed so as to overlap the belt27of the engine5in a top view. The second exhaust treatment device42is positioned in front of the center position ML of the engine5in the vehicle front and rear direction. Specifically, the rear edge of the second exhaust treatment device42is positioned in front of the center position ML of the engine5in the vehicle front and rear direction.

Here, referring toFIGS. 3 and 4, as seen from the side of the vehicle, the front edge F2of the second exhaust treatment device42is positioned behind the rear edge R1of the first exhaust treatment device41. Moreover, as seen from the side of the vehicle, the front edge F2of the second exhaust treatment device42is positioned behind the rear edge of the relay connection pipe43. Furthermore, a dotted line inFIGS. 3 and 4indicates a straight line along the vertical direction through the front edge F1of the first exhaust treatment device41. According to this, as seen from the side of the vehicle, the front edge F3of the relay connection pipe43is positioned behind the front edge F1of the first exhaust treatment device41. To express this in another way, the dot showing the central axial line A×3 of the relay connection pipe43is positioned behind the dot showing the central axial line A×1 of the first exhaust treatment device41.

FIGS. 3 and 4show straight lines VL, L1, L2, and L3as one dot chain lines. The straight line VL is a straight line passing through the dot indicating the central axial line A×1 of the first exhaust treatment device41, and extending in the vertical direction. The straight line L1is a straight line that connects the dot indicating the central axial line A×1 of the first exhaust treatment device41and the dot indicating the central axial line A×3 of the relay connection pipe43. The straight line L2is a straight line that connects the dot indicating the central axial line A×3 of the relay connection pipe43and the dot indicating the central axial line A×2 of the second exhaust treatment device42. And the straight line L3is a straight line that connects the dot indicating the central axial line A×1 of the first exhaust treatment device41and the dot indicating the central axial line A×2 of the second exhaust treatment device42. The straight line L1is inclined rearward with respect to the straight line VL by just θ1. And this angle θ1 between the straight line VL and the straight line L1is within the range from 0° to 20° inclusive. In other words, as seen from the side of the vehicle, the angle between the vertical direction and the straight line that joins the dot indicating the central axial line A×1 of the first exhaust treatment device41and the dot indicating the central axial line A×3 of the relay connection pipe43is within the range from 0° to 20° inclusive. And the straight line L2is inclined rearward with respect to the straight line VL by just θ2. This angle θ2 between the straight line VL and the straight line L2is within the range from 40° to 70° inclusive. In other words, as seen from the side of the vehicle, the angle between the vertical direction and the straight line that joins the dot indicating the central axial line A×3 of the relay connection pipe43and the dot indicating the central axial line A×2 of the second exhaust treatment device42is within the range front 40° to 70° inclusive. Yet further, the straight line L3is inclined rearward with respect to the straight line VL by just θ3. This angle θ3 between the straight line VL and the straight line L3is within the range from 10° to 40° inclusive. In other words, as seen from the side of the vehicle, the angle between the vertical direction and the straight line that joins the dot indicating the central axial line A×1 of the first exhaust treatment device41and the dot indicating the central axial line A×2 of the second exhaust treatment device42is within the range from 10° to 40° inclusive.

As shown inFIGS. 4 and 5, the second exhaust treatment device42includes a third connection port42aand a fourth connection port42b. The relay connection pipe43is connected to the third connection port42a. And the second connection pipe46is connected to the fourth connection port42b. In other words, the second connection pipe46is connected to the second exhaust treatment device42.

The third connection port42ais inclined forward and downward from the horizontal direction. And the fourth connection port42bprojects directly above. Due to this, the second connection pipe46projects upward above the engine5. The upper portion of the second connection pipe46projects upward from the engine cover13.

The engine5, the first connection pipe45, the first exhaust treatment device41, the relay connection pipe43, the second exhaust treatment device42, the second connection pipe46, and the exhaust conduit47are connected in series in that order. Accordingly, the exhaust from the engine5passes through the first connection pipe45and is fed into the first exhaust treatment device41. HC, CO, and SOF in the exhaust are mostly reduced by the first exhaust treatment device41. Next, the exhaust passes through the relay connection pipe43, and is fed into the second exhaust treatment device42. NOx in the exhaust is mostly reduced by the second exhaust treatment device42. And thereafter the cleaned exhaust passes through the second connection pipe46and the exhaust pipe47, and is discharged to the exterior.

Positional relationship of the exhaust treatment devices, the air cleaner, and the engine, and the shape of the engine cover.

As shown inFIGS. 2 through 4, the first exhaust treatment device41, the relay connection pipe43, the second exhaust treatment device42, and the air cleaner33are arranged so as to surround the front and the top of the engine5. Therefore, it is possible to arrange the first exhaust treatment device41, the relay connection pipe43, the second exhaust treatment device42, and the air cleaner33tightly close to one another.

Next, correspondence between the positions of the exhaust treatment devices and the air cleaner33and so on, and the shape of the engine cover13, will be explained. As shown inFIGS. 3 through 5, the engine cover13covers the engine5, the air cleaner33, the first exhaust treatment device41, the second exhaust treatment device42, the relay connection pipe43, and the injector44. And, as shown inFIGS. 3 and 4, the upper surface13aof the engine cover13extends along the second exhaust treatment device42and the air cleaner33. The front surface13bof the engine cover13extends along the first exhaust treatment device41and the relay connection pipe43. The engine cover13also includes a curved surface13cthat smoothly connects together its upper surface13aand its front surface13b. Due to the provision of the curved surface13c, the region of the upper portion of the blade15which the operator is able to check visually is extended.

FIG. 1illustrates the details of this situation.FIG. 1illustrates the region of the upper portion of the blade15which can be visually checked from the point of view100of an operator who is sitting in the cab12, as the region between straight lines110and120. The point of view100corresponds to the position of a filament position center point (FPCP) as defined in the specification of ISO 5006. The point of view100is a point that is just 680 mm upward in the vertical direction from the seat index point (SIP) as defined in the specification of ISO 5006. The straight line110is the straight line joining the point of view100and the upper edge of the blade15. And the straight line120is the straight line passing through the point of view100and contacting the engine cover13.

InFIG. 1, the straight line120is tangent to the curved surface13c, and it will be understood that provision of the curved surface13ccauses the region of the upper portion of the blade15which the operator is able to check visually to be extended. Moreover, as shown inFIG. 1, as seen from the side of the vehicle, the straight line that joins the point of view100and the upper edge of the blade15is positioned higher than the engine cover13.

FIG. 6is a left side view illustrating the positional relationship between the blade drive mechanism18, the exhaust treatment assembly40, and the engine cover13when the blade15is raised. InFIG. 6, the blade15is not illustrated. As shown inFIG. 6, due to the curved surface13cbeing provided to the engine cover13, the blade drive mechanism18is separated from the engine cover by at least the distance d, even when the blade15is raised. The distance d is a margin that is provided so as to ensure that the blade drive mechanism18does not collide with the engine cover13. An imaginary line that passes through the rear edge R4of the blade drive mechanism when the blade15is raised by the blade drive mechanism18to the greatest possible extent and that extends vertically is shown inFIG. 6by a one dot chain line. According to this, when the blade15is raised by the blade drive mechanism18to the greatest possible extent, the front surface13bof the engine cover13is positioned forward and below the rear edge R4of the blade drive mechanism. Furthermore, the front edge F1of the first exhaust treatment device41is also positioned forward and below the rear edge R4of the blade drive mechanism18.

Structure of the brackets that support the exhaust treatment devices, etc.

As shown inFIGS. 3 and 4, the main vehicle body3includes a mounting bracket50, a first support bracket70, a second support bracket80, a rear mounting bracket90, and dampers31L,31R,32L, and32R. The mounting bracket50includes a lower mounting bracket51, an upper mounting bracket52, a left mounting bracket53, and a right mounting bracket54. The mounting bracket50is disposed within the engine compartment8. The left mounting bracket53, the right mounting bracket54, and the rear mounting bracket90support the engine upon the vehicle body frame10via the dampers31L,31R,32L, and32R.

The mounting bracket50is attached to the engine5. Specifically, the left mounting bracket53and the right mounting bracket54are attached to the engine5. The lower mounting bracket51is attached to the left mounting bracket53and to the right mounting bracket54. The lower mounting bracket51supports the first support bracket70and the upper mounting bracket52. And the upper mounting bracket52supports the second support bracket80. The first support bracket70is attached to the mounting bracket50, and directly supports the first exhaust treatment device41. And the second support bracket80is attached to the mounting bracket50, and directly supports the second exhaust treatment device42.

FIG. 7is a left side view of the mounting bracket50, the first support bracket70, and the second support bracket80. Referring toFIGS. 3 and 7, the left mounting bracket53comprises a left mounting bracket base portion53b, a left mounting bracket attachment portion53a, a left mounting bracket protruding portion53e, and a left mounting bracket connection portion53c. The left mounting bracket base portion53bis a flat plate shaped member that extends approximately parallel to the left side of the engine5. The left mounting bracket attachment portion53ahas, for example, a through hole for passing a bolt. And, in a position corresponding to the left mounting bracket attachment portion53a, the engine5has a screw hole into which a bolt can be screwed and engaged. The left mounting bracket53is attached to the engine5by a bolt being passed through the left mounting bracket attachment portion53a, and by this bolt being screwingly engaged in the screw hole mentioned above. The left mounting bracket53is attached to the engine5in this manner via the left mounting bracket attachment portion53a. The left mounting bracket protruding portion53eis a member that protrudes in the leftward direction from the left mounting bracket base portion53b. The left mounting bracket protruding portion53ehas a left fixing hole53h. As shown inFIG. 3, the damper31L is attached in the left fixing hole53h. The damper31L is supported by the mounting bracket support portion10aof the vehicle body frame10.

The right mounting bracket64is built to be approximately symmetric with the left mounting bracket53. Referring toFIGS. 4 and 7, the right mounting bracket54includes a right mounting bracket base portion54b, a right mounting bracket attachment portion54a, a right mounting bracket protruding portion54e, and a right mounting bracket connection portion54c. The right mounting bracket base portion54bis a flat plate shaped member that extends approximately parallel to the right side of the engine5. The right mounting bracket attachment portion54aincludes, for example, a through hole for passing a bolt. And, in a position corresponding to the right mounting bracket attachment portion54a, the engine5has a screw hole into which a bolt can be screwed and engaged. The right mounting bracket54is attached to the engine5by a bolt being passed through the right mounting bracket attachment portion54a, and by this bolt being screwingly engaged in the screw hole mentioned above. The right mounting bracket54is attached to the engine54in this manner via the right mounting bracket attachment portion54a. The right mounting bracket protruding portion54eis a member that protrudes in the rightward direction from the right mounting bracket base portion54b. The right mounting bracket protruding portion54eincludes a right fixing hole54h. As shown inFIG. 4, the damper31R is attached in the right fixing hole54h. The damper31R is supported by the mounting bracket support portion10bof the vehicle body frame10.

Accordingly, the mounting bracket50is attached to the vehicle body frame10via the clampers31L and31R. The dampers31L and31R internally include elastic members made front rubber or the like. Consequently, the mounting bracket50is elastically supported via the dampers31L and31R upon the mounting bracket support portions10aand10bof the vehicle body frame10. Moreover, the left fixing hole53hand the right fixing hole54hare arranged so as to be mutually separated along the vehicle lateral direction. In other words, the dampers31L and31R are arranged so as to be mutually separated along the vehicle lateral direction.

Moreover the left mounting bracket attachment portion53aand the right mounting bracket attachment portion54aare herein collectively termed the “first connection portion”. Then, the mounting bracket50includes this first connection portion. The first connection portion is connected to the lower portion of the engine5. The lower portion of the engine5may, for example, be the portion of the engine5that is lower than the cylinder body24. The engine5is elastically supported upon the vehicle body frame10via the mounting bracket50and the dampers31L and31R.

Referring toFIGS. 3 and 7, the left mounting bracket connection portion53cis connected to the lower mounting bracket left connection portion51cof the lower mounting bracket51. In the example ofFIG. 7, the lower mounting bracket left connection portion51cincludes a through hole for passing a bolt, and the left mounting bracket connection portion53cincludes a screw hole into which a bolt can be screwed and engaged. And the lower mounting bracket51is attached to the left mounting bracket53by a bolt being passed through the lower mounting bracket left connection portion51c, and by this bolt being screwed into and engaged in the screw hole described above.

Referring toFIG. 4, the right mounting bracket connection portion54cis connected to the lower mounting bracket right connection portion51dof the lower mounting bracket51. The lower mounting bracket right connection portion51dincludes, for example, a through hole for passing a bolt, and the right mounting bracket connection portion54cincludes a screw hole into which a bolt can be screwed and engaged. And the lower mounting bracket51is attached to the right mounting bracket54by a bolt being passed through the lower mounting bracket right connection portion51d, and by this bolt being screwed into and engaged in the screw hole described above.

FIG. 8is a front view of the mounting bracket50, the first support bracket70, and the second support bracket80. As shown inFIGS. 7 and 8, the lower mounting bracket51extends from the lower mounting bracket left connection portion51cand the lower mounting bracket right connection portion51din the direction away from the left mounting bracket53and the right mounting bracket54(i.e. the forward direction, when installed to the bulldozer1) and moreover in the upward direction. In addition to the lower mounting bracket left connection portion51cand the lower mounting bracket right connection portion51d, the lower mounting bracket51includes a plurality of reinforcement plates51eand an upper surface51u. A lower attachment portion52bof the upper mounting bracket52is attached to the upper surface51u. In the example shown inFIG. 8, the upper surface51uand the lower attachment portion52bare fixed together by a plurality of screws.

Referring toFIGS. 7 and 8, the upper mounting bracket52comprises the lower attachment portion52b, an upper attachment portion52u, and a wall portion520. The lower attachment portion52bis a flat plate shaped member. The length of the lower attachment portion52bin the forward and rear direction is almost equal to the length of the diameter of the first exhaust treatment device41. Moreover, referring toFIG. 5, the length of the lower attachment portion52bin the lateral direction is almost equal to the length of the first exhaust treatment device41in the direction of its central axis A×1. The lower attachment portion52bis attached to the lower mounting bracket51. Furthermore, the first support bracket70is attached to the lower attachment portion52b. The lower attachment portion52b, the upper surface51uof the lower mounting bracket51, and the first support bracket70include through holes for insertion of bolts, and screw holes that are provided in positions corresponding to the through holes. The lower attachment portion52b, the upper surface51uof the lower mounting bracket51, and the first support bracket70are mutually fixed together by bolts being passed through the through holes described above, and by these bolts being screwed into and engaged in the screw holes described above.

The wall portion520extends in the vertical direction from a rear end portion of the tower attachment portion52bto a front end portion of the upper attachment portion52u. The rear end portion of the lower attachment portion52bis a portion of the lower attachment portion52bwhich is behind the first support bracket70attached to the lower attachment portion52b, and which is adjacent to the first support bracket70. And the front end portion of the upper attachment portion52uis a portion of the upper attachment portion52uwhich is in front of the second support bracket80attached to the upper attachment portion52u, and which is adjacent to the second support bracket80. As shown inFIG. 8, the wall portion520includes a flat plate shaped base portion521, longitudinal reinforcement plates522and523, a left reinforcement plate524, and a right reinforcement plate525. The longitudinal reinforcement plates522and523are flat plate members that extend along the vehicle front and rear direction. The reinforcement plates522and523include protruding portions522eand523ethat protrude forwards, below the central axis A×1 of the first exhaust treatment device41. The left reinforcement plate524is a flat plate shaped member that extends in the leftward direction from the longitudinal reinforcement plate522. And the right reinforcement plate525is a flat plate shaped member that extends in the rightward direction from the longitudinal reinforcement plate523. As shown in FIG.7, the left reinforcement plate524is bent in the forward direction at a point below the central axis A×1 of the first exhaust treatment device41, and is bent in the downward direction near the front edge of its protruding portion522e. In a similar manner, the right reinforcement plate525also is bent in the forward direction at a point below the central axis A×1 of the first exhaust treatment device41, and is bent in the downward direction near the front edge of its protruding portion523e. The longitudinal reinforcement plate523extends further upward above the upper attachment portion52u. And a fixing hole529for attachment of a lifting hook is formed at the upper edge of the longitudinal reinforcement plate523.

As shown inFIGS. 6 and 7, the upper attachment portion52uis positioned above the wall portion520. In other words, the upper attachment portion52uis supported underneath by the wall portion520. The base portion521of the wall portion520is connected to the front end portion of the upper attachment portion52u. The upper attachment portion52uis a flat plate shaped member that extends rearward from the abovementioned front end portion. The wall portion520includes an auxiliary support portion526that extends rearward from the base portion521, in order to support the second support bracket80and the second exhaust treatment device42, which are attached to the upper attachment portion52u, and the upper attachment portion52u. The upper attachment portion52uis attached to the auxiliary support portion526by welding. Moreover, the second support bracket80is attached to the upper attachment portion52uby welding. It should be understood that the second support bracket80could also be attached by some other attachment means, such as bolts and nuts or the like.

The mounting bracket50further includes a first intermediate connection portion61, a second intermediate connection portion62, and a third intermediate connection portion63. The first intermediate connection portion61, the second intermediate connection portion62, and the third intermediate connection portion63are connected to mutually different intermediate portions of the engine5. Such intermediate portions of the engine5may, for example, be portions which are above the crank case22of the engine5and which are below the upper surface of the cylinder head cover26. Let an upper portion of the engine5be a portion that is at the same level as or higher than the upper surface of the cylinder head cover26of the engine5, including the upper surface of the cylinder head cover26. An intermediate portion of the engine5is positioned between the upper portions and the lower portions of the engine. In the following explanation, the expression “third connection portion” will be employed as a collective term for the first intermediate connection portion61, the second intermediate connection portion62, and the third intermediate connection portion63. The first intermediate connection portion61, the second intermediate connection portion62, and the third intermediate connection portion63include through holes for passing bolts, and the mounting bracket50is fixed to intermediate portions of the engine5by bolts being passed through these screw holes and by these bolts being screwed into and engaged in screw holes provided upon the engine.

The mounting bracket50also includes a second connection portion64. As shown inFIG. 7, the second connection portion64is connected to an upper portion of the engine5as described above. The front edge of the second connection portion64is attached to the upper attachment portion52u. And the mounting bracket50further includes a relay connection pipe support portion65. The relay connection pipe support portion65is an approximately letter-L-shaped member that projects forward from the longitudinal reinforcement plate523. The relay connection pipe support portion65is connected to the right side surface of the longitudinal reinforcement plate523. The relay connection pipe support portion65includes a support surface66that is shaped in a circular are corresponding to the surface shape of the relay connection pipe43. A first fixing member67having a letter-U curved shape can be attached to the relay connection pipe support portion65. The relay connection pipe43is fixed by being clamped between the support surface66and the first fixing member67.

The lower attachment portion52b, the upper attachment portion52u, and the wall portion520integrally constitute the upper mounting bracket52. If the bolts in the lower attachment portion52band the upper surface51uof the tower mounting bracket are removed, then it is possible to take off the exhaust treatment assembly40with a lifting hook by employing the fixing hole529in the upper edge of the longitudinal reinforcement plate523while the exhaust treatment assembly is attached to the upper mounting bracket52. Accordingly, maintenance of the exhaust treatment assembly40becomes simple and easy.

Moreover, the mounting bracket50is attached to the engine5at a plurality of locations by the second connection portion64and the third connection portion (i.e. the first intermediate connection portion61, the second intermediate connection portion62, and the third intermediate connection portion63). Since a heavy object (the second exhaust treatment device42) is attached to the upper portion of the mounting bracket50, accordingly vibration of the upper portion of the mounting bracket50, in particular vibration thereof in the front and rear direction, can easily become great. However vibration of the upper portion of the mounting bracket50in the front and rear direction is reduced, since the second connection portion64and the third connection portion are fixed the mounting bracket52to the engine5at a plurality of locations.

The first support bracket70further includes a first left support portion73and a first right support portion74. The first left support portion73and the first right support portion74include upper surfaces that are formed as circular arcs corresponding to the shape of the cylindrical side surface of the first exhaust treatment device41. The first exhaust treatment device41is mounted to the first left support portion73and the first right support portion74. A second fixing member78having a letter-U curved shape can be attached to the first left support portion73. Moreover, a third fixing member79having a letter-U curved shape can be attached to the first right support portion74. The first exhaust treatment device41is fixed to the first support bracket70by the second fixing member78being fastened to the first left support portion73and the third fixing member79being fastened to the first right support portion74.

The first exhaust treatment device41is attached to the first support bracket70, and is supported on the engine5via the mounting bracket50. In other words, the first exhaust treatment device41is supported by the engine5via the first support bracket70and the mounting bracket50. Moreover, the mounting bracket50is elastically supported upon the vehicle body frame10. Accordingly, the first exhaust treatment device41is elastically supported upon the vehicle body frame10via the first support bracket70and the mounting bracket50.

The second support bracket80further comprises a second left support portion83and a second right support portion84. The second left support portion83and the second right support portion84include upper surfaces that are formed as circular arcs corresponding to the shape of the cylindrical side surface of the second exhaust treatment device42. The second exhaust treatment device42is mounted to the second left support portion83and the second right support portion84. A fourth fixing member88having a letter-U curved shape can be attached to the second left support portion83. Moreover, a fifth fixing member89having a letter-U curved shape can be attached to the second right support portion84. The second exhaust treatment device42is fixed to the second support bracket80by the fourth fixing member88being fastened to the second left support portion83and the fifth fixing member89being fastened to the third right support portion84.

The second exhaust treatment device42is attached to the second support bracket80, and is supported on the engine5via the mounting bracket50. In other words, the second exhaust treatment device42is supported by the engine5via the second support bracket80and the mounting bracket50. Moreover, the mounting bracket50is elastically supported upon the vehicle body frame10. Accordingly, the second exhaust treatment device42is elastically supported upon the vehicle body frame10via the second support bracket80and the mounting bracket50.

As shown inFIGS. 3 and 4, the rear mounting bracket90is attached to the rear surface of the flywheel housing6. In other words, the rear mounting bracket90is disposed behind the mounting bracket50. The rear mounting bracket90extends upward from the flywheel housing6. In other words, at least a part of the rear mounting bracket90is positioned above the fly wheel housing6. The rear mounting bracket90is positioned above the hydraulic pump7. The rear mounting bracket90is also positioned below the upper surface of the cylinder head cover26. The rear mounting bracket90is positioned below the cab12. It should be understood that, in the explanation of this embodiment, the described positions in the vertical direction of the mounting bracket50and the rear mounting bracket90are referred to the centers of these brackets in the vertical direction. Alternatively, they may be referred to the positions of the bearing surfaces of the brackets.

As shown inFIG. 3, the damper32L is supported by the mounting bracket support portion10cof the vehicle body frame10. And, as shown inFIG. 4, the damper32R is supported by the mounting bracket support portion10dof the vehicle body frame10. In other words, the rear mounting bracket90is attached to the vehicle body frame10via the dampers32L and32R. The dampers32L and32R are arranged as mutually separated along the vehicle lateral direction. The dampers32L and32R include internal elastic members made from rubber or the like. Accordingly, the rear mounting bracket90is elastically supported on the mounting bracket support portions10cand10dof the vehicle body frame10via the dampers32L and32R. The engine5is connected to the rear mounting bracket90via the flywheel housing6. Accordingly, the engine5is elastically supported upon the vehicle frame10via the rear mounting bracket90and the dampers32L and32R.

Characteristics

The bulldozer1according to this embodiment has the following characteristics.(1) In this bulldozer1, the first exhaust treatment device41is disposed in front of the engine5, while the second exhaust treatment device42is disposed above the engine5. And the longitudinal directions of the first exhaust treatment device41and the second exhaust treatment device42extend along the vehicle lateral direction. Moreover, as seen from the side of the vehicle, the front edge F2of the second exhaust treatment device42is positioned behind the rear edge R1of the first exhaust treatment device41. Due to this, even though the engine cover13includes the upper surface13athat slopes forward and downward, it is possible to avoid greatly raising that upper surface13aby housing the first exhaust treatment device41and the second exhaust treatment device42within the engine compartment8. As a result, it is possible to extend the region on the upper portion of the blade15of the working implement4which is visible to the operator, so that if is possible to avoid deterioration of the workability.(2) The upper edge of the relay connection pipe43that is disposed over the first exhaust treatment device41is positioned below the upper edge of the second exhaust treatment device42. Due to this, it is possible further to lower the height of the engine cover13by disposing the upper surface13aof the engine cover13that slopes forward and downward along the upper edge of the second exhaust treatment device42and along the upper edge of the relay connection pipe43. As a result, the operator is able visually to check a broader region upon the upper portion of the blade15of the working implement4.(3) The front edge F2of the second exhaust treatment device42is positioned behind the rear edge R3of the relay connection pipe43. Accordingly the second exhaust treatment device42is disposed at a position nearer to the rear end in the engine compartment8, where the height of the engine cover13rises. Thus, it is possible further to reduce the height of the engine cover13. As a result, the operator is able visually to check a broader region upon the upper portion of the blade15of the working implement4.(4) As seen from the front of the vehicle, the second exhaust treatment device42includes a portion that is overlapped over the relay connection pipe43. In other words, it becomes possible further to reduce the height of the engine cover13, since the height of the second exhaust treatment device42becomes lower. As a result, the operator is able visually to check a broader region upon the upper portion of the blade15of the working implement4.(5) The second exhaust treatment device42is positioned in front of the center position ML of the engine5in the front and rear direction. Due to this, it is possible to arrange the exhaust treatment assembly40in a tighter configuration, since it is possible to shorten the conduit between the relay connection pipe43and the second exhaust treatment device42. Accordingly maintenance of the exhaust treatment assembly40becomes simple and easy.(6) The air cleaner33is disposed above the engine5, and moreover below the upper surface13aof the engine cover13. Accordingly it is possible to take effective advantage of the package volume by disposing the air cleaner33in vacant space which is within the engine compartment8and which has been made available by housing the first exhaust treatment device41and the second exhaust treatment device42within the engine compartment8. In other words, by packing the components at high density in the interior of the engine compartment8, it is possible to make the engine compartment8more compact. As a result, it is possible for the operator visually to check a broader region upon the blade15of the working implement4.(7) The front edge F3of the relay connection pipe43is positioned behind the front edge F1of the first exhaust treatment device41. As a result, it is possible to provide the front surface13band/or the curved surface13cof the engine cover13more rearward. And, as a result, the operator is able visually to check a broader region upon the upper portion of the blade15of the working implement4.(8) The engine cover13includes the curved surface13cthat smoothly connects together the front surface13band the upper surface13a. Due to this, it is possible for the operator visually to check a broader region on the upper portion of the blade15of the working implement4, as compared to the case in which the front surface13band the upper surface13aare directly connected together.(9) The external diameter of the relay connection pipe43is shorter than the external diameter of the first exhaust treatment device41and the external diameter of the second exhaust treatment device42. As a result, it is possible to reduce the curvature of the curved surface13cof the engine cover13. In other words, it is possible to increase the radius of the circular arc that defines the curved surface13c. And, as a result, the operator is able visually to check a broader region upon the upper portion of the blade15of the working implement4.(10) The bulldozer1includes the blade drive mechanism18that drives the blade15. When the blade15is raised to the greatest possible extent by the blade drive mechanism18, the front surface13bof the engine cover13is positioned in front of and below the rear edge R4of the blade drive mechanism18. Furthermore, the front edge F1of the first exhaust treatment device41is also positioned in front of and below the rear edge R4of the blade drive mechanism18. Due to this, the first exhaust treatment device41is disposed in a space that, while being in front of the engine5, also is not affected by the operating region of the blade drive mechanism18. Accordingly it is possible to arrange the blade15in a position that is close to the cab12, even though the exhaust treatment device is disposed in front of the engine5.(11) The hydraulic pump7is disposed behind the engine5. If the hydraulic pump were to be disposed in front of the engine5, then it would be necessary to elongate the engine cover13forward, and the visibility of the upper portion of the blade15of the working implement4would be deteriorated. However, actually, the hydraulic pump7is disposed behind the engine5, while the first exhaust treatment device41is disposed in front of the engine5. Moreover, since the longitudinal direction of the first exhaust treatment device41extends along the vehicle lateral direction, accordingly it is possible to manage with a shorter length in the vehicle front and rear direction for accommodating the first exhaust treatment device41. Accordingly, it is possible to suppress protrusion forward of the engine cover13. As a result, the operator is able visually to check a broader region upon the upper portion of the blade15of the working implement4.(12) The cab12is arranged behind the engine5and moreover over the hydraulic pump7. Thus, in this bulldozer1, there is no dead space over the hydraulic pump7, since the cab12is positioned over the hydraulic pump7in this manner. Accordingly, with this bulldozer1, the method of this embodiment of disposing the exhaust treatment assembly40above or in front of the engine5is effective.(13) The first support bracket70that supports the first exhaust treatment device41and the second support bracket80that supports the second exhaust treatment device42are attached to the mounting bracket50. Due to this, the tasks of fixing the first exhaust treatment device41and the second exhaust treatment device42, or the tasks of taking them off, can be performed with each of the support brackets still being attached to the corresponding exhaust treatment device. Accordingly the tasks of fitting and removal become easy.(14) The mounting bracket50comprises the lower attachment portion52b, the upper attachment portion52u, and the wall portion520that extends in the vertical direction from the rear end portion of the lower attachment portion52bto the front end portion of the upper attachment portion52u. Due to this, it is possible to arrange the first exhaust treatment device41and the second exhaust treatment device42in sequence in the vertical direction, so that increase in the size of the engine compartment8can be restrained.(15) The mounting bracket50is connected to the lower portion of the engine5by the first connection portion (i.e. the left mounting bracket attachment portion53aand the right mounting bracket attachment portion54a). And the mounting bracket50is connected to the upper portion of the engine5by the second connection portion64. Moreover, the mounting bracket50is connected to the intermediate portion of the engine5by the third connection portion (i.e. the first intermediate connection portion61, the second intermediate connection portion62, and the third intermediate connection portion63). Accordingly, the mounting bracket50is compactly fixed to the engine5. Due to this, it is possible to suppress the amounts of protrusion of the upper surface13a, the front surface13b, and the curved surface13cof the engine cover13.

Modifications

While an embodiment of the present invention has been explained above, the present invention is not limited to the above described embodiment and various modifications are possible within the gist of the present invention.

The shapes of the mounting bracket50and the rear mounting bracket90are not limited to the aforementioned shapes, and they could be varied as appropriate. Moreover, the shapes of the first support bracket70and the second support bracket80are not limited to the aforementioned shapes described above, and they could be varied as appropriate. Yet further, the mounting bracket50, the first support bracket70, and the second support bracket do not need to be separate components, and they may be formed as a single integrated unit.

In the embodiment described above, it is described that the first exhaust treatment device41is a diesel oxidation catalyst device, while the second exhaust treatment device42is a selective catalytic reduction (SCR) device. However, the first exhaust treatment device41may be a selective catalytic reduction (SCR) device, while the second exhaust treatment device42may be a diesel oxidation catalyst device. But, since it is desirable for the exhaust from the engine to be fed into the diesel oxidation catalyst device first, in this case, the sequence and the orientations of the pipes that connect to the first exhaust treatment device41and the second exhaust treatment device42should be opposite.

It should be understood that it would also be possible for the first exhaust treatment device41not to be a diesel oxidation catalyst device, but to be a diesel particulate filter device.

The first exhaust treatment device41and the second exhaust treatment device42are not limited to being cylindrical or the like: they could have other shapes, for example they could be shaped as elliptic cylinders or rectangular parallelepipeds or the like. In this case, the shapes of the support portions (73,74) that support the first exhaust treatment device41and the shapes of the support portions (83,84) that support the second exhaust treatment device42would respectively correspond to the shapes of the side surfaces of the first exhaust treatment device41and to the shapes of the side surfaces of the second exhaust treatment device42.

There may be any number of dampers31L,31R,32L, and32R. However, it is desirable for the same number of dampers to be provided on the left side and on the right side.

Each of the number of the support portions (73,74) that support the first exhaust treatment device41, the number of the support portions (83,84) that support the second exhaust treatment device42, the number of the fixing members (78,79) that fix the first exhaust treatment device41, and the number of the fixing members (88,89) that fix the second exhaust treatment device42, is not limited to being two; these numbers may be one, or three or more.

The numbers and the positions of the holes for attaching the components included in the mounting bracket50, the first support bracket70, and the second support bracket80may be varied as appropriate. Moreover, the method of fixing shown in the embodiment is only given as an example, and it would also be possible to attach the components to the mounting bracket50, the first support bracket70, and the second support bracket80by some other method of fixing. For example, the fixing means may be by hooks, or by welding or the like.

According to the present invention, it is possible to provide a bulldozer with which deterioration of the workability is prevented, even though at least two exhaust treatment devices are housed in the engine compartment.