JP2008231999A - Construction vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction vehicle in which the freezing of a liquid reducer is suppressed. <P>SOLUTION: This construction vehicle comprises an engine 17; an exhaust emission control part 6; a liquid reducer tank 7; a vehicle body 4; and a counterweight part 5. The exhaust emission control part 6 reduces and purifies the nitrogen oxide contained in the exhaust gas of the engine 17 by using the liquid reducer. The liquid reducer tank 7 stores the liquid reducer. The vehicle body 4 has, therein, an engine room S1 in which the engine 17 is stored. The counterweight part 5 is mounted on the vehicle body 4, and disposed opposite to the engine room S1 and the liquid reducer tank 7. A duct 51 communicating with the engine room S1 and extending to the position opposite to the liquid reducer tank 7 is formed in the counterweight part 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a construction vehicle.

In order to reduce NOx (nitrogen oxide) in exhaust gas discharged from an internal combustion engine such as a diesel engine, a construction vehicle including an exhaust gas purification unit has been developed. The exhaust gas purification unit reduces and purifies nitrogen oxides contained in the exhaust gas using a liquid reducing agent such as an aqueous urea solution.
JP 2003-20936 A

  In the construction vehicle described above, a liquid reducing agent tank that stores the liquid reducing agent is provided. However, under an excessively low temperature environment, the liquid reducing agent stored in the liquid reducing agent tank may be frozen. For example, when a urea aqueous solution is used as the liquid reducing agent, the liquid reducing agent tank is desirably arranged in a temperature environment of 4 ° C. or higher, and the urea aqueous solution may freeze at a temperature lower than this.

  The subject of this invention is providing the construction vehicle which can suppress freezing of a liquid reducing agent.

  A construction vehicle according to a first invention includes an engine, an exhaust gas purification unit, a liquid reducing agent tank, a vehicle main body, and a counterweight unit. The exhaust gas purification unit reduces and purifies nitrogen oxides in the exhaust gas of the engine using a liquid reducing agent. The liquid reducing agent tank stores the liquid reducing agent. The vehicle body has an engine room in which an engine is housed. The counterweight portion is attached to the vehicle body and is disposed to face the engine room and the liquid reducing agent tank. The counterweight portion is formed with a duct that communicates with the engine room and extends to a position facing the liquid reducing agent tank.

  In this construction vehicle, warm air in the engine room is sent to the vicinity of the liquid reducing agent tank by a duct formed in the counterweight portion. Then, the liquid reducing agent tank is warmed by warm air from the engine room. Thereby, in this construction vehicle, freezing of a liquid reducing agent can be suppressed.

  A construction vehicle according to a second aspect of the invention is the construction vehicle of the first aspect, further comprising a cooling device. The cooling device is disposed adjacent to the engine room, and cools the engine by exchanging heat with the passing air. The vehicle body has a ventilation space inside. The ventilation space is a space that is located on the opposite side to the engine room with respect to the cooling device, and through which air taken from outside and sent to the cooling device passes. The liquid reducing agent tank is disposed in the ventilation space.

  The ventilation space is located on the opposite side to the engine room with respect to the cooling device, and is located on the upstream side of the cooling device, and thus does not reach a temperature as high as that of the engine room. Also, the liquid reducing agent tank is warmed by the warm air sent from the engine room through the duct, and does not become excessively low. Thereby, in this construction vehicle, the liquid reducing agent tank can be stored at an appropriate temperature by arranging the liquid reducing agent tank in the ventilation space.

  A construction vehicle according to a third aspect is the construction vehicle according to the second aspect, wherein one end of the duct communicates with the engine room, and the other end of the duct communicates with the ventilation space.

  In this construction vehicle, the air in the engine room is sent to the ventilation space through the duct and blown to the liquid reducing agent tank disposed in the ventilation space. Thereby, in this construction vehicle, freezing of a liquid reducing agent can be suppressed.

  A construction vehicle according to a fourth aspect is the construction vehicle according to the second aspect, wherein one end of the duct communicates with the engine room, and the other end of the duct is closed by a liquid reducing agent tank.

  In this construction vehicle, the air in the engine room is sent to the ventilation space through the duct and contacts at least a part of the liquid reducing agent tank disposed in the ventilation space. Thereby, in this construction vehicle, freezing of a liquid reducing agent can be suppressed.

  A construction vehicle according to a fifth aspect is the construction vehicle according to any one of the first to fourth aspects, wherein one end of the duct communicates with a lower portion of the engine room.

  In this construction vehicle, the air in the lower part of the engine room is sent to the vicinity of the liquid reducing agent tank through the duct. Since the air in the lower part of the engine room is not as hot as the air in the upper part of the engine room, it is possible to prevent the liquid reducing agent tank from being excessively warmed.

  A construction vehicle according to a sixth aspect of the present invention is the construction vehicle according to any one of the first to fifth aspects, further comprising an air guide. The air guide unit guides air in the engine room to the duct.

  In this construction vehicle, air in the engine room is guided to the duct by the air guide unit. Thereby, the air in an engine room becomes easy to enter a duct.

  A construction vehicle according to a seventh aspect of the present invention is the construction vehicle according to any one of the first to sixth aspects, wherein the duct is constituted by a concave groove provided in the counterweight portion.

  In this construction vehicle, the duct is configured by a concave groove provided in the counterweight portion. For this reason, formation of a duct is easy. Further, the duct can be formed without projecting a part of the counterweight portion to the engine room side.

  In the construction vehicle according to the present invention, warm air in the engine room is sent to the vicinity of the liquid reducing agent tank by a duct formed in the counterweight portion. Then, the liquid reducing agent tank is warmed by warm air from the engine room. Thereby, in this construction vehicle, freezing of a liquid reducing agent can be suppressed.

<Configuration>
A construction vehicle 1 according to an embodiment of the present invention is shown in FIG. The construction vehicle 1 is a hydraulic excavator, and includes a work machine 2, a lower traveling body 3, a vehicle main body 4, a counterweight unit 5, an exhaust gas purification unit 6 (see FIG. 4), and a liquid reducing agent tank 7. (See FIG. 4) and a liquid reducing agent pump 8 (see FIG. 4).

[Worker 2 and lower traveling body 3]
The work machine 2 is attached to the front portion of the vehicle body 4 and includes a boom 21, a boom cylinder 22, an arm 23, an arm cylinder 24, a bucket 25, a bucket cylinder 26, and the like. The work machine 2 operates when these cylinders 22, 24, and 26 are driven by hydraulic pressure, and can perform various operations.

  The lower traveling body 3 supports the vehicle body 4 and has a crawler traveling mechanism.

[Vehicle body 4]
The vehicle main body 4 is supported so as to be able to turn with respect to the lower traveling body 3, and includes a frame portion 40 (see FIG. 2), a cab 41, an exterior member 42, a fuel oil tank 43, a hydraulic oil tank 44, and the like.

  As shown in FIGS. 2 and 3, the frame unit 40 includes a center frame 10, a first side frame unit 11, a second side frame unit 12, a plurality of cross frame units 13, and a rear frame unit 14. Have.

  The center frame 10 is provided in the center of the frame portion 40 in the left-right direction, and the working machine 2 described above is attached thereto.

  The first side frame portion 11 and the second side frame portion 12 have an elongated shape extending in the front-rear direction, and are arranged at a distance from the center frame 10 with a distance therebetween, with the center frame 10 interposed therebetween. Has been.

  The cross frame portion 13 extends in the left-right direction, and is provided across the center frame 10 and the first side frame portion 11 or across the center frame 10 and the second side frame portion 12.

  The rear frame portion 14 is provided at the rear portion of the frame portion 40 and connects the rear ends of the center frame 10, the first side frame portion 11, and the second side frame portion 12.

  A driver's cab 41 shown in FIG. 1 is placed on a frame portion 40, and a seat and various operation members are provided therein.

  The exterior member 42 is attached to the frame portion 40 and constitutes the exterior surface of the vehicle body 4. The exterior member 42 includes an engine room cover member 15 and a ventilation space cover member 16. The engine room cover member 15 is a member that covers the upper side of the engine room S1 (see FIG. 2) in which the engine 17 is housed. The ventilation space cover member 16 is a member that covers the upper side and the side of the ventilation space S2 (see FIG. 2) that is taken in from the outside and sent to the cooling device 18 to be described later. A slit-like air inlet 19 is formed. The engine room S1 and the ventilation space S2 are arranged side by side in the left-right direction at the rear part of the vehicle body 4.

  The fuel oil tank 43 is a tank that stores fuel oil sent to the engine 17, and is provided on the right side of the vehicle body 4. In addition, in this specification, left and right shall mean right and left for the driver | operator who sees the working machine 2 ahead from the cab 41. FIG.

  The hydraulic oil tank 44 is a tank that stores hydraulic oil sent to the hydraulic pump, and is provided on the right side of the vehicle body 4.

  Further, an engine 17, a hydraulic pump (not shown), a cooling device 18, and the like are housed inside the vehicle body 4.

  The engine 17 is a diesel engine and serves as a drive source for driving the hydraulic pump. The engine 17 is disposed in the engine room S <b> 1 inside the vehicle body 4.

  The cooling device 18 is a device that cools the engine 17 by circulating a coolant such as water with the engine 17 and exchanging heat with the passing air. The cooling device 18 is disposed across the ventilation space S <b> 2 and the space S <b> 3 between the center frame 10 and the first side frame portion 11. The cooling device 18 is disposed adjacent to the engine room S1 and partitions the engine room S1 and the ventilation space S2. The cooling device 18 includes a heat exchange unit 31, a coolant tank 32, and a blower unit 33. The heat exchanging unit 31 is configured to allow air to pass therethrough and is provided with a pipe through which a cooling liquid passes. The coolant tank 32 is a tank that stores coolant, and is provided below the cooling device 18. The coolant tank 32 is located below the heat exchange unit 31, and is connected to the center frame 10 and the first frame. It arrange | positions in the space S3 between the side frame parts 11. FIG. The blower 33 generates a flow of air that is taken into the ventilation space S2 from the outside, passes through the heat exchange unit 31, and is sent to the engine room S1. Therefore, the ventilation space S2 is located on the upstream side of the air flow with respect to the cooling device 18, and is located on the opposite side of the engine room S1 with respect to the cooling device 18. The engine room S <b> 1 is located on the downstream side of the air flow with respect to the cooling device 18.

[Counterweight part 5]
The counterweight portion 5 is attached to the vehicle main body 4 in order to ensure stability during work, and is detachable from the vehicle main body 4. The counterweight portion 5 is formed by casting, but may be one in which a heavy object such as cement is filled in a sheet metal can. The counterweight part 5 covers the rear surface of the vehicle body 4 by being attached to the rear part of the vehicle body 4. More specifically, the counterweight portion 5 is fixed to the center frame 10 of the frame portion 40. Thereby, the counter weight part 5 is arrange | positioned facing the engine room S1 and the liquid reducing agent tank 7, and closes the ventilation space S2 mentioned above and the back of engine room S1.

  Further, a duct 51 extending from the engine room S 1 to a position facing the liquid reducing agent tank 7 is formed in the counterweight portion 5. As shown in FIG. 3, one end of the duct 51 communicates with the engine room S1 and is provided facing the lower part of the engine room S1. The other end of the duct 51 communicates with the ventilation space S2, and faces the liquid reducing agent tank 7 disposed in the ventilation space S2. The duct 51 includes a concave groove 52 provided on the front surface of the counterweight portion 5 and a duct cover member 53 that covers the side of the concave groove 52. The concave groove 52 is recessed backward from the front surface of the counterweight portion 5 and extends in the horizontal direction, specifically, in the left-right direction. The duct cover member 53 is attached to the counterweight portion 5 and covers the side of the concave groove 52 except for the inlet 54 of the duct 51 and the outlet 55 of the duct 51. The inlet 54 of the duct 51 is provided facing the engine room S1. The outlet 55 of the duct 51 is provided facing the ventilation space S2.

[Exhaust gas purification unit 6]
The exhaust gas purification unit 6 shown in FIG. 4 is a device that reduces and purifies nitrogen oxides in the exhaust gas of the engine 17 using a liquid reducing agent, and is disposed near the upper portion of the engine 17. Here, an aqueous urea solution is used as the liquid reducing agent. The exhaust gas purification unit 6 includes a first processing unit 61, a second processing unit 62, a first auxiliary processing unit 63, and a second auxiliary processing unit 64.

  The first processing unit 61 has a diesel particulate filter (hereinafter referred to as “DPF”) coated with an oxidation catalyst, collects particulates (particulate matter) in the exhaust gas, and also in the exhaust gas. Nitric oxide is oxidized to produce nitrogen dioxide. Nitrogen dioxide is unstable in a high-temperature atmosphere such as exhaust gas, and releases oxygen to return to nitric oxide. Then, the particulates collected in the DPF are burned by the oxidizing power of the released oxygen. Nitric oxide and nitrogen dioxide that could not be returned to the nitric oxide are sent to the first auxiliary processing unit 63. In addition, as a material of DPF, ceramics, such as cordierite and silicon carbide, or metals, such as stainless steel and aluminum, are used.

  The first auxiliary processing unit 63 has a hydrolysis catalyst, and decomposes urea in the liquid reducing agent supplied from the liquid reducing agent pump 8 to generate ammonia. The first processing unit 61 and the first auxiliary processing unit 63 are connected by a communication pipe 65, and the liquid reducing agent is supplied from the liquid reducing agent pump 8 (described later) to the exhaust gas passing through the communication pipe 65.

  The second processing unit 62 is an SCR (Selective Catalytic Reduction) type catalytic converter, and includes a urea denitration catalyst (DeNOx catalyst) made of a base metal such as zeolite or vanadium. The urea denitration catalyst reacts ammonia obtained from urea with NOx in the exhaust gas, and decomposes and purifies NOx into nitrogen and oxygen.

  The second auxiliary processing unit 64 has an oxidation catalyst, oxidizes the ammonia remaining in the second processing unit 62, decomposes it into nitrogen and water, and renders it harmless. The exhaust gas processed in the second auxiliary processing unit 64 is discharged to the outside through the exhaust pipe 34 (see FIG. 1) protruding upward from the engine room cover member 15.

[Liquid reducing agent tank 7 and liquid reducing agent pump 8]
The liquid reducing agent tank 7 shown in FIGS. 2 and 3 is a tank that stores the liquid reducing agent used in the exhaust gas purification unit 6. The liquid reducing agent tank 7 is disposed in the ventilation space S <b> 2 and is disposed close to the front surface of the counterweight unit 5. The liquid reducing agent tank 7 is located in front of the outlet 55 of the duct 51 provided in the counterweight portion 5.

  The liquid reductant pump 8 is connected to the liquid reductant tank 7 and the exhaust gas purification unit 6 by a pipe 66 (see FIG. 4). The liquid reductant stored in the liquid reductant tank 7 is supplied to the exhaust gas purification unit 6. To the connecting pipe 65. The liquid reducing agent pump 8 is disposed in the vicinity of the exhaust gas purification unit 6.

<Features>
(1)
Since a liquid reducing agent such as an aqueous urea solution is easily affected by temperature, it is desirable that the liquid reducing agent tank 7 be disposed in an appropriate temperature environment. Specifically, it is desirable that the liquid reducing agent tank 7 is disposed in a temperature environment of 4 ° C. to 60 ° C., and the urea aqueous solution may freeze or crystallize at a temperature higher or lower.

  Therefore, in this construction vehicle 1, a duct 51 that connects the engine room S1 and the ventilation space S2 is provided in the counterweight portion 5, and warm air in the engine room S1 passes through the duct 51 and is disposed in the ventilation space S2. To the liquid reducing agent tank 7. Thereby, it can suppress that the temperature of a liquid reducing agent falls and a liquid reducing agent freezes. Moreover, since the liquid reducing agent tank 7 is arrange | positioned in the ventilation space S2, and the ventilation space S2 is located upstream from the engine room S1, it does not become hot as much as the engine room S1. For this reason, it can suppress that the temperature of a liquid reducing agent rises too much and a liquid reducing agent crystallizes.

  Thus, in this construction vehicle 1, the liquid reducing agent can be stored in an appropriate temperature environment.

(2)
In the construction vehicle 1, the duct 51 can be easily configured by providing the concave groove 52 in the front surface of the counterweight portion 5. For this reason, the duct 51 can be provided in the construction vehicle 1 with few additional parts.

  Further, compared to the case where the duct 51 is provided in the installation space in the vehicle main body 4 such as the engine room S1 and the ventilation space S2, a new installation space is not required, so that the vehicle main body 4 is prevented from being enlarged. be able to.

(3)
In the construction vehicle 1, the temperature reduction of the liquid reducing agent can be prevented by using the heat from the engine 17. For this reason, heating equipment, such as a heater, becomes unnecessary, and the manufacturing cost of the construction vehicle 1 can be reduced. In addition, an increase in energy consumption can be suppressed.

<Other embodiments>
(A)
In the above embodiment, the present invention is applied to the hydraulic excavator. However, the present invention can also be applied to other construction vehicles 1.

(B)
In the above embodiment, the urea aqueous solution is used as the liquid reducing agent, but other reducing agents may be used.

(C)
In the above embodiment, the duct 51 is configured by the concave groove 52 and the duct cover member 53. However, the duct 51 may be configured by only the concave groove 52 without the duct cover member 53 being provided. Also in this case, warm air in the engine room S1 is sent to the liquid reducing agent tank 7 through the duct 51. In addition, since the duct 51 is configured, an increase in the number of parts can be suppressed.

  Further, the duct 51 may be configured by a tunnel-shaped passage instead of the concave groove 52. Also in this case, since the duct 51 is configured, an increase in the number of parts can be suppressed.

(D)
In the above embodiment, the liquid reducing agent tank 7 is provided in the ventilation space S <b> 2, but the place where the liquid reducing agent tank 7 is disposed is a place where it is in contact with warm air sent through the duct 51. Good.

(E)
In the above embodiment, the other end of the duct 51, that is, the outlet 55 of the duct 51 is open, but may be closed by the liquid reducing agent tank 7. Also in this case, the warm air sent from the engine room S1 to the outlet 55 of the duct 51 comes into contact with the liquid reducing agent tank 7 and the liquid reducing agent tank 7 is warmed.

(F)
In the construction vehicle 1 according to the above embodiment, as shown in FIG. 5, the duct 51 may be provided with an air guide portion 56 that guides air in the engine room S <b> 1. The air that flows through the engine room S <b> 1 is guided to the inlet 54 of the duct 51 by the air guide unit 56, so that the air can easily enter the duct 51.

  The present invention has an effect of suppressing the freezing of the liquid reducing agent, and is useful as a construction vehicle.

The external appearance perspective view of a construction vehicle. The perspective view which shows the structure inside a construction vehicle. The top view in FIG. The block diagram which shows the structure of an exhaust-gas purification | cleaning part. The top view which shows the structure inside the construction vehicle which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Construction vehicle 4 Vehicle main body 5 Counterweight part 6 Exhaust gas purification part 7 Liquid reducing agent tank 17 Engine 18 Cooling device 51 Duct 52 Groove 56 Air guide part S1 Engine room S2 Ventilation space

Claims (7)

Engine,
An exhaust gas purification unit for reducing and purifying nitrogen oxides in the exhaust gas of the engine using a liquid reducing agent;
A liquid reducing agent tank for storing the liquid reducing agent;
A vehicle body having an engine room in which the engine is stored;
A counterweight portion attached to the vehicle body and disposed opposite to the engine room and the liquid reducing agent tank;
With
The counterweight portion is formed with a duct that communicates with the engine room and extends to a position facing the liquid reducing agent tank.
Construction vehicle. A cooling device that is disposed adjacent to the engine room and cools the engine by exchanging heat with air passing therethrough;
The vehicle main body has a ventilation space inside which the air taken in from the outside that is located on the opposite side to the engine room with respect to the cooling device and sent to the cooling device passes.
The liquid reducing agent tank is disposed in the ventilation space.
The construction vehicle according to claim 1. One end of the duct communicates with the engine room,
The other end of the duct communicates with the ventilation space.
The construction vehicle according to claim 2. One end of the duct communicates with the engine room,
The other end of the duct is closed by the liquid reducing agent tank.
The construction vehicle according to claim 2. One end of the duct communicates with the lower part of the engine room,
The construction vehicle according to any one of claims 1 to 4. An air guide for guiding air in the engine room to the duct;
The construction vehicle according to any one of claims 1 to 5. The duct is configured by a concave groove provided in the counterweight portion.
The construction vehicle according to any one of claims 1 to 6.

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