JP5939570B2 - Airframe and work machine - Google Patents

Description

  The present invention relates to a machine body equipped with an exhaust gas treatment apparatus using a liquid reducing agent, and a work machine equipped with the machine body.

  Urea water is used as a liquid reducing agent for reducing the nitrogen oxides in the exhaust gas of the internal combustion engine. The thermal decomposition temperature of this urea water is about 150 ° C., and the freezing temperature of the urea water is urea 32. In the case of 5% concentration (trade name: AdBlue), it is −11 ° C., so conventionally, it is often arranged near the heat source to warm the urea water tank to prevent freezing. Further, in view of the vehicle layout, the urea water tank and the urea water supply pipe are often installed in a machine room such as an engine room and near a high temperature object such as an engine or a hydraulic tank. Furthermore, the urea water tank and the urea water supply pipe may be heated by engine cooling exhaust air or engine coolant to prevent freezing.

  For example, a branch port other than the exhaust port of this exhaust air is provided on the lee side of the high temperature engine cooling exhaust air generated in the machine room where the engine is installed, and a urea water tank is installed from this branch port An air duct duct-like air passage is provided to the equipment room, and urea water supply piping is arranged from the urea water tank installed in the equipment room through the air duct duct-like air passage to the urea water injection device to There is a working machine that uses a part to heat urea water to prevent freezing of urea water (see, for example, Patent Document 1).

  Also known is a urea water piping structure that prevents the urea water from freezing by heating the urea water with the engine cooling liquid by adopting a double pipe structure in which the engine cooling liquid piping is arranged on the outer periphery of the urea water piping. (For example, refer to Patent Document 2).

JP 2010-285814 A JP 2009-068348 A

  In a traveling vehicle such as a truck, a urea water injection device and a muffler are cooled by wind during traveling. However, in a working machine that performs stationary work such as a hydraulic excavator, heat tends to be accumulated in the engine room and the temperature tends to be high.

  When the urea water tank and the urea water supply pipe are arranged in a place where the temperature is extremely high such as a machine room such as an engine room, the temperature of the urea water approaches the thermal decomposition temperature, and there is a concern about performance degradation.

  Due to the characteristics of the exhaust gas treatment device, the urea water injection device is installed in the vicinity of an exhaust pipe such as a muffler, and the urea water injection device itself may become high temperature, so urea water supplied to the urea water injection device If the temperature is not controlled to an appropriate temperature, there is a concern that the thermal decomposition temperature of the urea water will be reached before being injected into the exhaust gas treatment device. There is a high need to block heat conduction from the heat source to the urea water.

  Further, both the one that heats urea water using part of the engine cooling exhaust air of Patent Document 1 and the one that heats urea water using the engine coolant of Patent Document 2 place emphasis on the prevention of freezing of urea water. Therefore, the function of keeping the urea water as a liquid reducing agent at an appropriate temperature by blocking the heat conduction from the heat source to the urea water is not sufficient.

  The present invention has been made in view of the above points, and includes a machine body excellent in the function of maintaining a liquid reducing agent for reducing nitrogen oxide in engine exhaust gas at an appropriate temperature, and a work machine including the machine body. The purpose is to provide.

The invention described in claim 1 includes a machine room, an engine installed in the machine room, an exhaust gas treatment apparatus provided in the machine room for reducing nitrogen oxides in exhaust gas, and liquid reduction in the exhaust gas treatment apparatus. The reductant supply device is disposed from the liquid reductant supply source disposed at a position not affected by the engine heat to the exhaust gas treatment device in the machine room. Reducing agent supply piping, air passage forming means that is an air passage duct having a rectangular cross section provided around the reducing agent supply piping at least at a position affected by the heat of the engine, and liquid reducing agent supply in the air passage forming means The airframe includes cooling air introduction means for forcibly introducing cooling air from the source side to the exhaust gas treatment apparatus side .

請 Motomeko 2 invention described, the air passage duct in the body of claim 1, wherein is formed a U-shaped cross-sectional member of the machine room, by the outer cover plate mounted freely opened and closed with respect to the machine room It is a thing.

According to a third aspect of the present invention, the exterior cover plate in the airframe according to the second aspect includes an opening for ventilation.

According to a fourth aspect of the present invention, the cooling air introduction means in the airframe according to any one of the first to third aspects is a blower provided on the upstream side of the air passage forming means.

According to a fifth aspect of the present invention, the cooling air introduction means in the airframe according to any one of the first to third aspects is a suction device provided on the downstream side of the air passage forming means.

The invention described in claim 6 is a work machine including the machine body according to any one of claims 1 to 5 and a work device mounted on the machine body.

According to the first aspect of the present invention, in the airframe equipped with the reducing agent supply device that supplies the liquid reducing agent to the exhaust gas treatment device, the reducing agent supply device is a position that is not affected by the heat of the engine installed in the machine room. reducing agent supply pipe over the exhaust gas treatment apparatus of the machine room is disposed from arranged liquid reductant source, the rectangular cross-sectional shape provided around the reducing agent supply pipe at a position affected by heat of at least the engine wind Cooling air is forcibly introduced from the liquid reducing agent supply source side to the exhaust gas treatment device side by the cooling air introducing means in the air passage forming means that is a duct duct, and a sufficient ventilation gap is provided on the outer peripheral side of the reducing agent supply pipe. easily can be be formed, it is possible to ensure a sufficient amount of cooling air by the cooling air by blocking efficiently heat conduction from the heat source to the reducing agent supply pipe, the reducing agent supply pipe in the machine room Heated is prevented from being excessively rise in temperature, the liquid reducing agent of nitrogen oxides in the exhaust gas of the engine to reduction treatment can be kept at an appropriate temperature.

According to the invention 請 Motomeko 2, wherein the air passage duct, a U-shaped cross-sectional member of the machine room, if formed by the outer cover plate mounted freely opened and closed with respect to the machine room, the air passage duct It is easy to form, and maintenance in the air duct can be facilitated simply by opening the exterior cover plate.

According to the third aspect of the present invention, when an opening for ventilation is provided in the exterior cover plate, cooling air is efficiently ventilated by the opening, and an excessive temperature rise in the air duct is prevented. Therefore, heat exchange between the reducing agent supply pipe and the cooling air can be efficiently performed.

According to the fourth aspect of the present invention, when the air blower is provided on the upstream side of the air passage of the air passage forming means, the installation location of the air blower has a degree of freedom.

According to the fifth aspect of the present invention, when the suction device is provided downstream of the air passage forming means, the air passage forming means can be shortened.

According to the sixth aspect of the present invention, in a work machine that performs stationary work or low-speed moving work, heat is likely to be trapped in the machine room and the temperature tends to be high. Cooling air is forcibly introduced by the cooling air introduction means, and heat conduction from the heat source to the reducing agent supply pipe can be efficiently blocked by this cooling air, and the liquid reducing agent can be maintained at an appropriate temperature.

It is a perspective view which shows one related technique of the airframe which concerns on this invention. It is sectional drawing which shows one related technique of the air path formation means with respect to the reducing agent supply apparatus of an airframe same as the above. It is a side view of the working machine provided with the aircraft body same as the above. It is a disassembled perspective view which shows one Embodiment of an aircraft body same as the above. It is sectional drawing which shows the air path formation means of the body shown by FIG. It is a perspective view which shows the U-shaped cross-section member of the body shown by FIG. It is a perspective view which shows the connection state of the air path formation means and suction device of the body shown by FIG. It is the perspective view which looked at the state by which the reducing agent supply piping was drawn in in the exterior cover board of the body shown by FIG. 4 from the front side.

Hereinafter, the present invention will be described in detail based on one related technique shown in FIGS. 1 to 3 and one embodiment shown in FIGS.

First, one related technique shown in FIGS. 1 to 3 will be described.

  As shown in FIG. 3, the excavator-type work machine 10 includes a machine body 11 including a lower traveling body 12 and an upper revolving body 13 provided on the lower traveling body 12 so as to be able to swivel. A bucket-type working device 14 is mounted on the upper swing body 13 of the above.

  A cab 15 provided with an operator's driver's seat and a storage box 16 for storing tools and the like are provided on the upper swing body 13 via a work device 14. A fuel tank 17 and a hydraulic oil tank 18 are provided behind the storage box 16. An engine 21 is installed in a machine room (engine room) 19 in the airframe 11 located behind the slewing bearing portion of the upper swing body 13, and a counterweight 22 is mounted on the rear end.

  As shown in FIG. 1, a radiator, an oil cooler, and a cooling fan that cools these by applying cooling air sucked from the outside to one side of an engine 21 installed in a machine room 19 of the upper swing body 13. An exhaust gas treatment device 24 for purifying exhaust gas from the exhaust system of the engine 21 in the machine room 19 is disposed on the other side of the engine 21. A plurality of hydraulic pumps (not shown) driven by the engine 21 are disposed in the pump chamber located below the exhaust gas treatment device 24.

  The exhaust gas treatment device 24 includes a black smoke removal device (Diesel Particulate Filter) 25 that removes black smoke in the exhaust gas, and a nitrogen oxide reduction device that reduces nitrogen oxide in the exhaust gas ( Selective Catalytic Reduction) 26 is connected in series by a pipe 27, and the nitrogen oxide reducing device 26 is a reducing agent injection device such as an injector that injects a liquid reducing agent such as urea water into the upstream pipe 27. Has 28.

  A reducing agent supply device 31 for supplying a liquid reducing agent such as urea water to the nitrogen oxide reducing device 26 is provided for the reducing agent injection device 28 provided in the pipe 27 on the upstream side of the nitrogen oxide reducing device 26. It has been.

  The reducing agent supply device 31 is configured to store a liquid reducing agent tank 32 for storing the liquid reducing agent installed in the storage box 16 as a position not affected by the heat of the engine 21, and the liquid reducing agent in the liquid reducing agent tank 32. The liquid reducing agent pump 33 as a liquid reducing agent supply source for pumping and discharging, and the reducing agent injection device 28 of the nitrogen oxide reducing device 26 in the machine room 19 from the liquid reducing agent pump 33 through the piping path in the machine body 11 And a reducing agent supply pipe 34 such as a urea water supply pipe (so-called urea line).

  Further, as shown in FIG. 1, an air passage pipe 35 having a diameter larger than that of the reducing agent supply pipe 34 is provided around the reducing agent supply pipe 34 as an air passage forming means over almost the entire length of the reducing agent supply pipe 34. Yes.

  That is, as shown in FIG. 2, the air passage pipe 35 is a steel pipe or a flexible resin pipe that is loosely fitted to the outside of the reducing agent supply pipe 34 via the ventilation gap 36. May be made of a heat insulating material, or the outer surface of the air duct pipe 35 may be covered with a heat insulating material 37. The air passage pipe 35, the ventilation gap 36, and the heat insulating material 37 prevent the heat of the hydraulic oil tank 18 and the machine room 19 from being transmitted to the reducing agent supply pipe 34.

  The horizontal portion of the air duct pipe 35 is preferably a steel pipe. Further, it is desirable to use a heat-resistant resin pipe having flexibility at the rising portion in the machine room 19.

  As a cooling air introduction means for forcibly introducing the cooling air into the ventilation gap 36 in the air passage pipe 35, a blower 38 such as a blower fan is provided on the upstream side of the air passage of the air passage pipe 35.

  That is, as shown in FIG. 1, the start end of the large-diameter air pipe 35 is connected to the air outlet of the blower 38 installed in the storage box 16, and the reducing agent is supplied into the air pipe 35. Piping 34 is inserted.

  The middle part of the double structure of the reducing agent supply pipe 34 and the air duct pipe 35 is inserted into the machine room 19 (engine 21 room) through the tank mount frame 39 constituting the upper swing body 13 and the machine room. 19 is disposed up to the exhaust gas treatment device 24, and the end of the reducing agent supply pipe 34 is connected to a reducing agent injection device 28 located upstream of the nitrogen oxide reducing device 26. Further, the end portion of the air passage pipe 35 is opened in front of the reducing agent injection device 28.

  In the vicinity of the reducing agent injection device 28, the temperature in the air passage pipe 35 or the reducing agent supply pipe 34 rises most, so a temperature detection device (not shown) is provided at that location, and air is blown according to the detected temperature. The device 38 may be on / off controlled or proportionally controlled. On / off control controls fan driving / stopping according to a threshold, and proportional control controls fan rotation speed according to temperature.

  Note that the blower fan 38 or the like is provided on the upstream side of the air passage pipe 35, but a suction device such as a suction fan may be provided on the downstream end of the air passage pipe 35. It may be.

Next, the function and effect of the related technique shown in FIGS. 1 to 3 will be described.

  The reducing agent supply device 31 pumps a liquid reducing agent such as urea water in the liquid reducing agent tank 32 in the storage box 16 by the liquid reducing agent pump 33, and the exhaust gas treatment device in the machine room 19 through the reducing agent supply pipe 34. , And is injected upstream of the nitrogen oxide reduction device 26 by the reducing agent injection device 28.

  At the same time, cooling air is forcibly introduced into the air duct pipe 35 provided around the reducing agent supply pipe 34 by the blower 38, and the hydraulic oil tank 18, engine 21, and black smoke are removed by this cooling air. Heat conduction from the heat source such as the device 25 and the nitrogen oxide reduction device 26 to the reducing agent supply pipe 34 is cut off over almost the entire length of the reducing agent supply pipe 34 to prevent an excessive temperature rise of the reducing agent supply pipe 34 and Try to keep the reducing agent at the proper temperature.

  At that time, the temperature of the liquid reducing agent is detected by a temperature detecting device (not shown) provided in the air passage pipe 35 or the reducing agent supply pipe 34 in the vicinity of the reducing agent injection device 28, and in the on / off control, The detected temperature and the threshold are compared, and if the detected temperature is equal to or higher than the threshold, the blower 38 is driven, and if the detected temperature is lower than the threshold, the blower 38 is stopped. In the proportional control, the fan rotation speed of the blower 38 is increased and controlled in response to an increase in the detection temperature of the liquid reducing agent, and the ability to cool the liquid reducing agent is increased, thereby increasing the temperature of the liquid reducing agent. Control to precision.

  As described above, in the work machine including the reducing agent supply device 31 that supplies the liquid reducing agent to the exhaust gas treatment device 24, the reducing agent supply device 31 includes the engine 21 installed in the machine room 19 in the machine body 11, and the like. A reducing agent supply pipe 34 is arranged from the liquid reducing agent tank 32 and the liquid reducing agent pump 33 installed in the storage box 16 that is not affected by the heat from the exhaust gas treatment device 24 in the machine room 19, and this reducing agent supply pipe. Since the cooling air is forcibly introduced by the air blower 38 into the air duct pipe 35 provided around the 34, the heat conduction from the heat source to the reducing agent supply pipe 34 is effectively blocked by this cooling air, The reducing agent supply pipe 34 can be prevented from being heated excessively by the heat in the hydraulic oil tank 18 and the machine room 19, and the liquid reducing agent that reduces nitrogen oxides in the exhaust gas of the engine 21 can be prevented at an appropriate temperature. Can be kept in.

  When the air passage forming means is the air passage pipe 35 loosely fitted to the outside of the reducing agent supply pipe 34 via the ventilation gap 36, the heat conduction from the heat source to the reducing agent supply pipe 34 is reduced to the reducing agent supply pipe 34. It is easy to efficiently shut off the entire length of 34, and the reducing agent injection device 28, which is a high temperature region of the exhaust gas treatment device 24, and its surroundings are cooled by the cooling air blown from the opening of the end of the air pipe 35. You can also.

  When the air blower 38 is provided upstream of the air passage pipe 35, a utility space such as the storage box 16 can be used, and the installation location of the air blower 38 is flexible.

Next, an embodiment shown in FIGS. 4 to 8 will be described. Parts similar to those of the related art shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof is simplified.

  That is, the work machine 10 includes a body 11, a work device 14 mounted on the body 11, an engine 21 mounted on the body 11, and nitrogen oxides in exhaust gas provided for the exhaust system of the engine 21. And an exhaust gas treatment device 24 for reducing the gas.

  As shown in FIG. 4, the nitrogen oxide reduction device 26 of the exhaust gas treatment device 24 has an upstream on the counterweight 22 side, and injects a liquid reducing agent such as urea water on the upstream side of the nitrogen oxide reduction device 26. A reducing agent injection device 28 such as an injector is provided. A reducing agent supply device 31 for supplying a liquid reducing agent to the reducing agent injection device 28 of the nitrogen oxide reducing device 26 is provided.

  The reducing agent supply device 31 is configured to store a liquid reducing agent tank 32 for storing the liquid reducing agent installed in the storage box 16 as a position not affected by the heat of the engine 21, and the liquid reducing agent in the liquid reducing agent tank 32. A liquid reducing agent pump 33 as a liquid reducing agent supply source for pumping and discharging is provided, and a reducing agent supply pipe 34 disposed from the liquid reducing agent pump 33 to the reducing agent injection device 28 of the exhaust gas treatment device 24.

  On the other hand, in the portion corresponding to the machine room 19, one air passage duct 41 and the other air passage duct 42 are continuously provided around the reducing agent supply pipe 34 as air passage forming means. The air ducts 41 and 42 are formed in a rectangular cross-sectional shape, and a suction device 43 such as a suction fan as a cooling air introduction means for forcibly introducing cooling air into the air ducts 41 and 42, Arranged between the exhaust gas treatment device 24 and the counterweight 22.

  As shown in FIG. 5, one air duct duct 41 provided on one side surface of the machine room 19 opens toward the outside, which is installed horizontally at the upper part of the machine room 19 as shown in FIG. 4. The U-shaped cross-section member 44 and an exterior cover plate 46 attached to the machine room 19 by a hinge 45 so as to be opened and closed are formed. The exterior cover plate 46 in the closed state is in close contact with the U-shaped cross-section member 44 to form an air duct having a rectangular cross-section.

  In short, the air duct 41 having one side of the exterior cover plate 46 is provided so as to penetrate the machine room 19, and the reducing agent supply pipe 34 is inserted into the air duct 41. The machine room 19 and the air duct 41 are separated from each other by the wall of the U-shaped cross-section member 44.

  As shown in FIGS. 4 and 5, the exterior cover plate 46 has a ventilation opening 47 at a position corresponding to the U-shaped cross-section member 44. Further, by providing an opening 47 for ventilation in the exterior cover plate 46 that forms one side of the air duct 41, the ventilation air is efficiently ventilated by the opening 47, and excessive air in the air duct 41 Since the temperature rise can be prevented, heat exchange between the reducing agent supply pipe 34 and the cooling air can be efficiently performed.

  As shown in FIG. 6, the reducing agent supply pipe 34 is fixed by a holding plate 48 attached in the U-shaped cross-section member 44 in a state where the reducing agent supply pipe 34 is piped in the U-shaped cross-section member 44 of the machine room 19. It is drawn into the machine chamber 19 through a hole 49 or notch formed in the letter-shaped cross-section member 44 and connected to a reducing agent injection device 28 provided on the inlet side of the nitrogen oxide reduction device 26.

  As shown in FIGS. 5 and 6, a ventilation gap 50 is formed between the air duct 41 having a rectangular cross section and the reducing agent supply pipe 34 to ensure a sufficient air volume.

  As shown in FIG. 7, the other air passage duct 42 continuously provided in one air passage duct 41 has a horizontal portion 52 of a rectangular cross-section member 51 formed in an L shape, and the one air passage duct 41. The suction part 43 is connected to the end face of the suction part 43, and is inclined with respect to the horizontal part 52. The suction part 43 serves as a cooling air introduction means arranged on the downstream side of the air duct of the air duct 42. Connected to mouth 54.

  As shown in FIG. 8, when the exterior cover plate 46 of the machine room 19 and the exterior cover plate 56 of the fuel tank 17 and the hydraulic oil tank 18 are closed, the reducing agent supply pipe 34 is connected to these exterior cover plates 46, 56. It will be in a state of being drawn in and will not be exposed to the outside.

Similar to the related art , a temperature detection device (not shown) is provided at the temperature rise portion of the air ducts 41 and 42 or the reducing agent supply pipe 34, and the suction device 43 is controlled on / off according to the detected temperature. Alternatively, proportional control may be performed.

  As cooling air introduction means, a suction device 43 such as a suction fan is provided on the downstream side of the air ducts 41 and 42, but a blower device such as a blower fan is provided on the upstream side of the air passage of the air duct 41. However, excessive temperature rise can be prevented. In this case, the ventilation opening 47 provided in the exterior cover plate 46 becomes the cooling air discharge opening 47.

  Next, the function and effect of the embodiment shown in FIGS. 4 to 8 will be described.

  The reducing agent supply device 31 pumps a liquid reducing agent such as urea water in the liquid reducing agent tank 32 in the storage box 16 by the liquid reducing agent pump 33, and the exhaust gas treatment device in the machine room 19 through the reducing agent supply pipe 34. , And is injected upstream of the nitrogen oxide reduction device 26 by the reducing agent injection device 28.

  At the same time, cooling air is forcibly introduced by the suction device 43 into the air ducts 41 and 42 provided around the reducing agent supply pipe 34 in the machine room 19, and the black smoke removing device 25 is introduced by this cooling air. In addition, heat conduction from a heat source such as the nitrogen oxide reducing device 26 to the reducing agent supply pipe 34 is cut off, an excessive temperature rise in the reducing agent supply pipe 34 is prevented, and the liquid reducing agent is kept at an appropriate temperature.

  At that time, the temperature of the liquid reducing agent is detected by a temperature detection device (not shown) provided in the air ducts 41 and 42 or in the reducing agent supply pipe 34, and a suction device is provided according to the temperature of the liquid reducing agent. It is desirable to control 43 on / off or proportionally.

  As described above, in the working machine including the reducing agent supply device 31 that supplies the liquid reducing agent to the exhaust gas treatment device 24, the reducing agent supply device 31 is affected by the thermal effect of the engine 21 installed in the machine room 19 in the machine body 11. A reductant supply pipe 34 is provided from the liquid reductant tank 32 and the liquid reductant pump 33 installed in the storage box 16 that is not subject to the exhaust gas treatment device 24 in the machine room 19, and the reductant supply pipe 34 Since the cooling air is forcibly introduced into the air ducts 41 and 42 provided around by the suction device 43, the heat conduction from the heat source to the reducing agent supply pipe 34 can be effectively blocked by this cooling air, and the reduction A work machine that can prevent the agent supply pipe 34 from being heated excessively by being heated in the machine room 19 and maintaining the liquid reducing agent that reduces nitrogen oxides in the exhaust gas of the engine 21 at an appropriate temperature. 10 can be offered.

  When the air ducts 41 and 42 are ducts having a rectangular cross section, it is easy to form a sufficient ventilation gap 50 on the outer peripheral side of the reducing agent supply pipe 34, and a sufficient amount of cooling air can be secured.

  When the air duct 41 is formed by the U-shaped cross-section member 44 of the machine room 19 and the exterior cover plate 46 attached to the machine room 19 so as to be openable and closable, the air duct 41 can be easily formed. At the same time, maintenance inside the air duct 41 can be facilitated simply by opening the exterior cover plate 46.

  When the opening 47 for ventilation is provided in the exterior cover plate 46, the ventilation air is efficiently ventilated by the opening 47, and an excessive temperature rise in the air duct 41 can be prevented. Heat exchange between the agent supply pipe 34 and the cooling air can also be efficiently performed.

  When the suction device 43 is provided on the downstream side of the air duct 42, the air ducts 41 and 42 can be formed short only to the length corresponding to the machine room 19.

  As described above, when the reducing agent supply pipe 34 is inserted into the machine room 19 of the machine body 11 or the exterior cover plate 46, the reducing agent supply pipe 34 is provided in the machine room 19 or the exterior cover plate 46. It is isolated from the heat source by being arranged in the large-diameter air duct pipe 35 or the air duct ducts 41 and 42, and further, cooling air is introduced into the air duct pipe 35 or the air duct ducts 41 and 42. As a result, the liquid reducing agent is supplied to the reducing agent injection device 28 in a state of being maintained at an appropriate temperature.

  Note that the present invention can be applied to a machine driven by an engine in addition to a work machine, for example, a transport machine.

  The present invention has industrial applicability to those who manufacture or sell airframes and work machines.

10 work machines
11 Aircraft
14 Working equipment
19 Machine room
21 engine
24 Exhaust gas treatment equipment
31 Reducing agent supply device
33 Liquid Reductant Pump as Liquid Reductant Supply Source
34 Reducing agent supply piping
35 air passage pipes of a wind path forming means
38 Blower as means for introducing cooling air
41, 42 Air ducts as a means of forming air ducts
43 Suction device as cooling air introduction means
44 U-shaped cross-section member
46 Exterior cover plate
47 Ventilation openings

Claims (6)

A machine room,
An engine installed in the machine room,
An exhaust gas treatment device provided in the machine room for reducing nitrogen oxide in exhaust gas;
In a machine equipped with a reducing agent supply device for supplying a liquid reducing agent to an exhaust gas treatment device,
The reducing agent supply device
A reducing agent supply pipe arranged from a liquid reducing agent supply source arranged at a position not affected by the heat of the engine to an exhaust gas treatment device in the machine room;
An air passage forming means that is an air passage duct having a rectangular cross-sectional shape provided around the reducing agent supply pipe at a position at least affected by the heat of the engine;
An airframe comprising: cooling air introduction means for forcibly introducing cooling air from the liquid reducing agent supply source side to the exhaust gas treatment device side in the air passage forming means . Air passage duct, the aircraft according to claim 1, wherein the U-shaped cross-sectional member of the machine room, that is formed by the outer cover plate mounted freely opened and closed with respect to the machine room. The airframe according to claim 2 , wherein the exterior cover plate includes an opening for ventilation. The airframe according to any one of claims 1 to 3 , wherein the cooling air introducing means is a blower provided on the upstream side of the air passage of the air passage forming means. The airframe according to any one of claims 1 to 3 , wherein the cooling air introduction means is a suction device provided downstream of the air passage forming means. An airframe according to any one of claims 1 to 5 ,
A work machine comprising: a work device mounted on a machine body.

Images