JP2008231757A - Construction vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction vehicle having a function of reducing nitrogen oxides and capable of suppressing an increase in size. <P>SOLUTION: This construction vehicle comprises an engine 17, an exhaust emission control part 6, a vehicle body 4, a counterweight part 5, and a liquid reducer tank 7. The exhaust emission control part 6 reduces and removes the nitrogen oxides contained in the exhaust gas of the engine 17 by using a liquid reducer. The vehicle body 4 stores the engine 17 and the exhaust emission control part 6. The counterweight part 5 is mounted on the vehicle body 4, and having a recessed part 51 therein. The liquid reducer tank 7 stores the liquid reducer, and disposed in the recessed part 51 of 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, since a liquid reducing agent tank for storing the liquid reducing agent is provided, an installation space for the liquid reducing agent tank is required. For this reason, there exists a possibility that a construction vehicle may enlarge.

  An object of the present invention is to provide a construction vehicle that has a function of reducing nitrogen oxides and can suppress an increase in size.

  A construction vehicle according to a first aspect of the present invention includes an engine, an exhaust gas purifying unit, a vehicle body, a counterweight unit, and a liquid reducing agent tank. The exhaust gas purification unit reduces and purifies nitrogen oxides in the exhaust gas of the engine using a liquid reducing agent. The vehicle main body houses an engine and an exhaust gas purification unit. The counterweight portion is attached to the vehicle body and has a recess. The liquid reducing agent tank stores the liquid reducing agent and is disposed in the recess of the counterweight portion.

  In this construction vehicle, the exhaust gas purification unit can reduce and purify nitrogen oxides in the exhaust gas of the engine using the liquid reducing agent stored in the liquid reducing agent tank. Further, since the liquid reducing agent tank is disposed in the concave portion of the counterweight portion, it is possible to suppress an increase in installation space in the vehicle body due to the provision of the liquid reducing agent tank. For this reason, this construction vehicle has a function of reducing nitrogen oxides and can suppress an increase in size.

  A construction vehicle according to a second aspect of the present invention is the construction vehicle of the first aspect, wherein the recess is formed on the inner surface of the counterweight portion facing the vehicle body.

  In this construction vehicle, the concave portion is formed on the inner surface of the counterweight portion that faces the vehicle body, and is provided inside the counterweight that is invisible or difficult to see from the outside. For this reason, even when the counterweight collides with an external obstacle, the liquid reducing agent tank is hardly damaged.

  A construction vehicle according to a third aspect of the present invention is the construction vehicle of the second aspect, wherein the liquid reducing agent tank is attached to the vehicle body.

  In this construction vehicle, the liquid reducing agent tank is not attached to the counterweight part but attached to the vehicle body. Although the counterweight part may collide with an external obstacle, in this construction vehicle, since the liquid reducing agent tank is not attached to the counterweight part, the impact is prevented from being transmitted from the counterweight part to the liquid reducing agent. be able to.

  A construction vehicle according to a fourth aspect is the construction vehicle according to the third aspect, wherein the counterweight portion is detachable from the vehicle body.

  In this construction vehicle, the liquid reducing agent tank is attached to the vehicle body and is not attached to the counterweight portion. For this reason, when removing a counterweight part from a vehicle main body, or when attaching to a vehicle main body, piping etc. which are connected to a liquid reducing agent tank do not get in the way. Thereby, attachment and detachment of a counterweight can be performed easily.

  A construction vehicle according to a fifth aspect of the present invention is the construction vehicle according to any one of the second to fourth aspects of the present invention, further comprising a cooling device that cools the engine by exchanging heat with the passing air. The vehicle main body has a ventilation space through which air taken in from the outside and sent to the cooling device passes. And the recessed part is provided facing the ventilation space.

  In this construction vehicle, the liquid reducing agent tank is arranged facing the ventilation space located on the upstream side of the cooling device. Since this ventilation space is a stable temperature environment for the liquid reducing agent, the liquid reducing agent is stably stored.

  In the construction vehicle according to the present invention, the exhaust gas purifying unit can reduce and purify nitrogen oxides in the exhaust gas of the engine using the liquid reducing agent stored in the liquid reducing agent tank. Further, since the liquid reducing agent tank is disposed in the concave portion of the counterweight portion, it is possible to suppress an increase in installation space in the vehicle body due to the provision of the liquid reducing agent tank. For this reason, this construction vehicle has a function of reducing nitrogen oxides and can suppress an increase in size.

<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. 3), and a liquid reducing agent tank 7. (See FIG. 3) and a liquid reducing agent pump 8 (see FIG. 3).

[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 FIG. 2, the frame part 40 includes a center frame 10, a first side frame part 11, a second side frame part 12, a plurality of cross frame parts 13, and a rear frame part 14.

  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 between the center frame 10 and the first side frame portion 11. The cooling device 18 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. Accordingly, the ventilation space S <b> 2 is located on the upstream side of the air flow with respect to the cooling device 18, and 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 placed on a portion of the center frame 10 that protrudes behind the rear frame portion 14 and is fixed to the center frame 10. Thereby, the counterweight part 5 closes the back of the ventilation space S2 and engine room S1 which were mentioned above.

  A concave portion 51 is formed on the inner surface of the counterweight portion 5 facing the vehicle body 4, that is, on the front surface of the counterweight portion 5. The recess 51 has a shape that is recessed from the front surface of the counterweight portion 5 toward the rear, and is provided facing the ventilation space S2. The bottom surface inside the recess 51 is located at the same height as the top surface of the rear frame portion 14 described above, and is generally flush.

[Exhaust gas purification unit 6]
The exhaust gas purification unit 6 shown in FIG. 3 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]
A liquid reducing agent tank 7 shown in FIG. 2 is a tank for storing a liquid reducing agent used in the exhaust gas purification unit 6. The liquid reducing agent tank 7 is disposed in the recess 51 of the counterweight portion 5 and is disposed facing the ventilation space S2. The liquid reducing agent tank 7 is not attached to the counterweight portion 5 but attached to the vehicle body 4. More specifically, the liquid reducing agent tank 7 is fixed to the rear frame portion 14.

  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. 3). 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)
In this construction vehicle 1, the exhaust gas purification unit 6 can reduce and purify nitrogen oxides in the exhaust gas of the engine 17 using the liquid reducing agent stored in the liquid reducing agent tank 7. Further, the liquid reducing agent tank 7 is disposed in the recess 51 of the counterweight portion 5, and a space for providing the liquid reducing agent tank 7 is formed without expanding the installation space inside the vehicle body 4. For this reason, the increase in the installation space by providing the liquid reducing agent tank 7 is suppressed. Thereby, in this construction vehicle 1, while having the function to reduce a nitrogen oxide, enlargement can be suppressed.

(2)
In this construction vehicle 1, the liquid reducing agent tank 7 is not attached to the counterweight portion 5 but is attached to the vehicle body 4. The counterweight unit 5 may collide with an external obstacle when the vehicle body 4 turns, but in this construction vehicle 1, the liquid reducing agent tank 7 is not attached to the counterweight unit 5. Can be prevented from being transmitted from the counterweight part 5 to the liquid reducing agent.

  Further, when the counterweight portion 5 is detached from the vehicle body 4, the counterweight portion 5 can be detached from the vehicle body 4 while the liquid reducing agent tank 7 is attached to the vehicle body 4. For this reason, it is not necessary to remove the piping and wiring connected to the liquid reducing agent tank 7, and these piping and wiring do not become an obstacle to the removal of the counterweight unit 5. The same applies when the counterweight portion 5 is attached to the vehicle body 4. Thereby, attachment to the vehicle main body 4 of the counterweight part 5 and removal from the vehicle main body 4 can be performed easily.

(3)
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, the liquid reducing agent tank 7 is disposed facing the ventilation space S <b> 2 located on the upstream side of the cooling device 18. The ventilation space S2 is located on the upstream side of the engine room S1, and therefore does not become as hot as the engine room S1. Further, since the ventilation space S2 is close to the engine room S1, there is little risk of excessively low temperatures. For this reason, the liquid reducing agent tank 7 can be stably stored by arranging the liquid reducing agent tank 7 so as to face the ventilation space S2.

  Further, the liquid reducing agent tank 7 is disposed in the concave portion 51 that is recessed backward from the front surface of the counterweight portion 5, and does not protrude into the ventilation space S2. For this reason, there is little possibility of obstructing the flow of the air taken into ventilation space S2.

  The entire liquid reducing agent tank 7 is not limited to be housed in the recess 51, but the liquid reducing agent tank 7 protrudes from the recess 51, and a part of the liquid reducing agent tank 7 protrudes into the ventilation space S2. Also good. Also in this case, a part of the liquid reducing agent tank 7 is disposed inside the recess 51, so that a portion of the liquid reducing agent tank 7 that is disposed in the ventilation space S2 is reduced. Thereby, the influence which the liquid reducing agent tank 7 has on the flow of air passing through the ventilation space S2 can be reduced.

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

(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 concave portion 51 is provided on the front surface of the counterweight portion 5, but it may be provided in another portion. In this case, from the viewpoint of protecting the liquid reducing agent tank 7 from an external impact, a recess 51 is provided on the inner surface of the counterweight portion 5 facing the vehicle body 4, and the liquid reducing agent tank 7 is provided in the recess. Is preferably arranged.

  In the above embodiment, the front surface of the counterweight portion 5 faces the vehicle body 4. However, when the upper surface and the lower surface of the counterweight portion 5 face the vehicle body 4, the recess 51 is formed in these portions. May be provided.

  Furthermore, in the above embodiment, the recess 51 may be formed over both the front surface and the upper surface of the counterweight portion 5. This is particularly effective when the counterweight portion 5 is moved upward and removed from the vehicle body 4 or when the counterweight portion 5 is attached to the vehicle body 4 from above.

  INDUSTRIAL APPLICABILITY The present invention has a function of reducing nitrogen oxides and has an effect of suppressing an increase in size, 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 block diagram which shows the structure of an exhaust-gas purification | cleaning part.

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 Recessed part S2 Ventilation space

Claims (5)

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 vehicle body that houses the engine and the exhaust gas purification unit;
A counterweight portion attached to the vehicle body and formed with a recess;
A liquid reducing agent tank that stores the liquid reducing agent and is disposed in a recess of the counterweight portion;
Construction vehicle equipped with. The concave portion is formed on an inner surface of the counterweight portion facing the vehicle body,
The construction vehicle according to claim 1. The liquid reducing agent tank is attached to the vehicle body.
The construction vehicle according to claim 2. The counterweight portion is detachable from the vehicle body.
The construction vehicle according to claim 3. Further comprising a cooling device for cooling the engine by exchanging heat with the passing air;
The vehicle main body has a ventilation space through which air taken in from the outside and sent to the cooling device passes,
The recess is provided facing the ventilation space.
The construction vehicle according to any one of claims 2 to 4.

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