JP4787859B2 - Arrangement structure of liquid reducing agent tank for NOx reduction catalyst in construction machinery - Google Patents

Description

  The present invention relates to a liquid reducing agent tank used in an engine with a NOx reduction catalyst, and more particularly to a liquid reducing agent tank arrangement structure in a construction machine that enables temperature management of the liquid reducing agent.

  A reduction catalyst is often used to reduce NOx in exhaust gas of a diesel engine and to purify the exhaust gas. In order to reduce NOx absorbed by the reduction catalyst, a reducing agent is supplied upstream of the reduction catalyst to promote the reduction reaction. As the reducing agent, there are nitrogen compounds, carbon monoxide, and the like, but in recent years, an aqueous solution in which urea is dissolved in water is considered promising.

  The reducing agent needs to be stored in the tank and disposed on the vehicle body. The size of the liquid reductant tank is small compared to fuel tanks and does not require a large space, but it is necessary to secure a certain space while considering the supply path to the engine exhaust pipe, etc. In the present situation, it is difficult to secure a space for disposing the liquid reducing agent tank.

  Although not related to the tank of liquid reducing agent, this tank is installed inside the counterweight provided at the rear of the vehicle body in order to place a tank for compressed natural gas on a construction machine with little installation space. Is disclosed in Patent Document 1.

On the other hand, since the urea aqueous solution of the liquid reducing agent freezes at around −10 ° C., there is a problem that the freezing causes trouble during cold weather. As means for solving this problem, there is one disclosed in Patent Document 2. In this publication, the liquid reductant tank is placed in a location where heat can be kept in the vehicle body of the construction machine (for example, near a heat source such as an engine) to prevent the liquid reductant from freezing. The simple structure is low in cost and has the effect of not wasting energy for heat insulation. In addition, the vicinity of these heat sources can be expected to have an effect of preventing freezing because a certain temperature is maintained after the construction machine is used.
JP 2001-40705 A JP 2003-20936 A

  The construction machine is provided with a counterweight in order to balance the weight of the vehicle body. Since this counterweight has a role that greatly affects the work performance, the inside is filled with a weight adjusting material such as concrete.

  Therefore, although the embodiment and examples are given in the one disclosed in Patent Document 1, the structure in which the tank is arranged at the center or the whole of the counterweight needs to provide a lot of tank space inside the counterweight. Therefore, it is considered difficult to fill the necessary weight adjusting material, and it is difficult to evenly fill the weight adjusting material into the counterweight. Also, construction machines need to fix and fix the tank because large vibrations and shocks are applied to the car body depending on the work contents. However, considering the filling of the weight adjusting material, the tank is fixed at the center of the counterweight. It is difficult to produce this structure.

  In addition, if the urea aqueous solution leaks from the tank, including the one in Patent Document 2, there is a possibility that corrosion or the like may occur in the counterweight or in the vicinity of the engine.

  Further, the one disclosed in Patent Document 2 is useful when the temperature is low, such as when it is cold, but does not describe when the temperature is high, that is, when the temperature inside the vehicle body rises. There is no consideration for the rise. Since urea aqueous solution generates NH3 (ammonia) at around 40 ° C., there is a concern about influence on the human body at the time of replenishment and change in concentration of the aqueous solution. Also, no consideration is given when the liquid reducing agent is scattered due to damage to the tank. The position and method of arrangement are also lacking in specificity. In addition, since the vicinity of the heat source such as the vicinity of the engine is difficult to access from the ground, there is also a problem that workability when the urea aqueous solution tank is replenished is not good.

  The arrangement structure of the liquid reducing agent tank for the NOx reduction catalyst in the construction machine of the present invention is for solving the above-mentioned problem, and the liquid reducing agent tank can be easily arranged in a construction machine having a limited installation space. It is an object of the present invention to provide an arrangement structure of a liquid reducing agent tank for a NOx reduction catalyst that can prevent influence on others even if the liquid reducing agent leaks and has good replenishment workability.

  In order to solve each of the above problems, the present invention employs the following means.

  The invention according to claim 1 is a counterweight provided on a vehicle body frame, a liquid reducing agent tank housing space provided in the counterweight and having an opening in a rear plate or an upper plate, and the tank A tank storage chamber formed by a partition member provided in the storage space and separated from the filling material of the counterweight, a lid member for closing the tank storage chamber so as to be openable and closable, and a liquid reducing agent provided in the tank storage chamber It is characterized by comprising a tank and a fixing means between the tank storage chamber and the liquid reducing agent tank.

  According to a second aspect of the present invention, in the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to the first aspect, the liquid for NOx reduction catalyst is provided between the tank housing chamber and the liquid reducing agent tank. A tank storage box formed of a material that does not react with the reducing agent is provided.

  According to a third aspect of the present invention, in the arrangement structure of the liquid reducing agent tank for the NOx reduction catalyst of the construction machine according to the first or second aspect, the fixing means includes the liquid reducing agent tank and the tank housing chamber or It is characterized by being configured by fitting a concave portion and a convex portion provided along the longitudinal direction of the tank storage box.

  According to a fourth aspect of the present invention, in the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to any one of the first to third aspects, the tank housing chamber, the liquid reducing agent tank, A heat insulating material is provided between the tank storage chamber and the tank storage box, or between the tank storage box and the liquid reducing agent tank.

  According to a fifth aspect of the present invention, in the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to any one of the first to fourth aspects, the tank accommodating chamber, the tank accommodating box, the liquid A temperature detection device for detecting any temperature in the reducing agent tank, a communication opening that communicates the tank storage chamber with the outside, a movable louver that opens and closes the communication opening, and a temperature signal from the temperature detection device And a control device for controlling the movable louver.

  A sixth aspect of the present invention is the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to any one of the first to fourth aspects, wherein the tank accommodating chamber, the tank accommodating box, the liquid A temperature detection device for detecting any temperature in the reducing agent tank, a communication opening that communicates the tank storage chamber with the outside, and exhausts air in the tank storage chamber to the outside, or stores external air in the tank A fan introduced into the room and a control device for controlling the fan based on a temperature signal from the temperature detection device are provided.

  Since the arrangement structure of the liquid reducing agent tank for the NOx reduction catalyst of the construction machine according to the present invention is configured as described above, it is easy to manufacture the counterweight. Also, corrosion of the tank chamber can be prevented. By fixing the liquid reducing agent tank, it is possible to prevent the liquid reducing agent tank from being damaged due to vibrations or the like when the vehicle is operated. Regarding the ambient temperature of the liquid reducing agent tank, consideration is given not only at low temperatures but also at high temperatures. It becomes easy to replenish the liquid reducing agent. It can be discharged when gas is generated in the tank chamber. It becomes easier to clean the tank storage chamber.

Embodiment 1
1st Embodiment of the arrangement structure of the liquid reducing agent tank for NOx reduction catalysts of the construction machine of this invention is described using FIGS.

  FIG. 1 is a plan view of a hydraulic excavator as a construction machine to which the present invention is applied. The hydraulic excavator is generally composed of a traveling body 1, a revolving body 2 provided on the traveling body 1, and a working device (not shown) attached to a working device attachment portion 3 provided in front of the revolving body 2.

  The swivel body 2 is covered with a cab 4 provided on the left front of a swivel frame (not shown), an engine 5 provided at the rear of the cab 4, a hydraulic pump 6 driven by the engine 5, and a building cover 7. A machine room 8 in which a hydraulic device (not shown) for controlling the pressure oil discharged by the hydraulic pump 6 is accommodated, and a counterweight 9 provided behind the machine room 8 are provided. The machine room 8 is provided with a purification device for purifying the exhaust gas discharged as the engine 5 is driven. This purification device is a known urea SCR that reduces NOx in exhaust gas using a urea aqueous solution stored in a urea water tank described later.

  FIG. 2 is a perspective view showing the internal structure of the counterweight 9, and FIG. 3 is a cross-sectional view taken along the line AA in FIG. The counterweight 9 is formed in a container shape from a rear plate 10 that forms a rear surface portion and right and left side portions, an upper surface plate 11 that forms an upper surface portion, a lower surface plate 12 that forms a lower surface portion, and a front plate 13 that forms a front surface. Then, the inside is filled with a weight adjusting material 14 such as concrete.

  Further, a tank housing space 16 having an opening 15 formed in the left side surface portion of the rear plate 10 is provided in the lower left portion inside the counterweight 9, and the partition plate 17 and the rear plate 10 are provided in the tank housing space 16. A tank accommodating chamber 18 is provided that is partitioned by the left side surface portion, the lower surface plate 12 and the front surface plate 13. The opening 15 is provided with a door 19 for closing and opening the opening 15.

  Further, the tank housing chamber 18 is provided with a urea water tank 20 for storing a urea aqueous solution as a liquid reducing agent. The urea water tank 20 is provided with a urea water replenishing port 22 that is closed by a cap 21 on one side (opening 15 side).

  4 is a cross-sectional view taken along the line BB in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line CC in FIG. 4, showing the structure of the tank storage chamber 18 and the like in detail. In the figure, the tank housing chamber 18 is defined by a partition plate 17 made of a steel plate or the like provided in the tank housing space 16, and a heat insulating material 23 made of resin or the like is affixed to the inner surface thereof. Furthermore, a box-shaped tank storage box 24 made of a material (such as stainless steel) that is resistant to urea is provided in the tank storage chamber 18 to which the heat insulating material 23 is attached. The tank storage box 24 is also provided with an opening on the opening 15 side. Further, as shown in FIG. 5, the tank storage box 24 and the tank storage chamber 18 are formed in the longitudinal direction from the opening 15 side to the inward side on the four outer surfaces of the upper and lower surfaces and the front and rear surfaces of the tank storage box 24, respectively. Longitudinal direction extending from the opening 17 side to the inward side so as to correspond to the convex portion 25, penetrating the protruding convex portion 25 and the heat insulating material 23, and corresponding to the convex portion 25. It is fixed by fitting with a recess 26 provided in the. The urea water tank 20 and the tank storage box 24 are convex portions 27 that extend in the longitudinal direction from the opening 17 side toward the inward side on the three outer surfaces of the lower surface and the front and rear surfaces of the urea water tank 20, respectively. And fixed to the lower surface and the front and rear surfaces of the inner surface of the tank storage box 24 by fitting with a concave portion 28 provided in the longitudinal direction from the opening 17 side toward the inner side so as to correspond to the convex portion 27. These convex portions 25 and 27 and concave portions 26 and 28 constitute a fixing means.

  The first embodiment configured as described above has the following operational effects.

(1) Since the counterweight 9 has a large mass, the damping rate of vibration is also large, and excessive vibration and impact do not act on the urea water tank 20 accommodated therein.

(2) Since the tank storage chamber 18 for storing the urea water tank 20 is provided in the side portion (corner portion) of the counterweight 9, it can be easily provided as compared with the case where a space is provided in the central portion. Further, the filling of the weight adjusting material 14 can be performed smoothly as in the conventional case. Moreover, it is easy to access the replenishment port 22 of the urea water tank 20, and replenishment work is easy.

(3) Since the heat insulating material 23 is provided in the tank housing chamber 20, the heat of the engine 5 adjacent to the front plate 13 and the front side of the counterweight 9 is cut off, and the urea water tank 20 is not easily affected by the heat. it can. Further, since the urea water tank 20 is provided in the counterweight 9, it is possible to obtain a heat insulation effect even by the weight adjusting material 14, and a heat insulation effect can be obtained on both the low temperature side and the high temperature side, and the temperature change of the urea aqueous solution can be reduced. Can be reduced.

(4) Since the tank storage box 24 is further provided inside the heat insulating material 23 of the tank storage chamber 18 and the tank storage box 24 is made of a material that is corrosion resistant to urea, Even if the aqueous solution leaks, the counterweight 9 itself and the heat insulating material 23 are not affected by corrosion or the like.

(5) Recesses 26, 28 and protrusions provided in the longitudinal direction from the opening 15 side are respectively fixed to the tank storage box 24 and the tank storage chamber 18 and fixed to the urea water tank 20 and the tank storage box 24. Since the parts 25 and 27 are fitted to each other, the tank housing box 24 can be easily attached to and detached from the tank housing chamber 18 from the opening 15. Even if it leaks out, it can be easily removed. In addition, when the urea aqueous solution is replenished, the urea water tank 20 can be pulled out from the opening 15 along the uneven portion, and replenishment from the replenishing port 22 can be facilitated.

<< Embodiment 2 >>
Next, a second embodiment will be described with reference to FIG. In this embodiment, a communication hole 29 (for providing an opening in the front plate 13 and the tank storage box 24 of the counterweight 9 in the first embodiment described above to communicate the upper space of the tank storage box 24 with the outside is provided. A temperature detector 30 is provided in the tank housing box 24, a movable louver 31 whose opening and closing is controlled by the temperature in the tank housing box 24, and a temperature detection And a control device 32 for controlling the opening and closing of the movable louver 31 based on the temperature detected by the device 30.

  According to this embodiment, when the temperature in the tank storage box 24 is lower than a predetermined set temperature by the temperature detector 30 and there is a possibility of freezing of urea water, the louver 31 is opened and adjacent. By taking the heat generated by the engine 5 into the tank housing box 24, the urea aqueous solution can be prevented from freezing.

<< Embodiment 3 >>
Next, a third embodiment will be described with reference to FIG. In this embodiment, an electric fan 33 is provided in the communication hole 29 in place of the movable louver 31 in the second embodiment.

  Thereby, when the temperature in the tank storage box 24 is lower than the predetermined temperature, the freezing of the urea aqueous solution can be surely prevented by forcibly guiding the heat of the engine 5 to the inside. Further, by rotating the fan 33 in the reverse direction, when the temperature in the tank housing box 24 is higher than a predetermined temperature and ammonia is generated from the urea aqueous solution, it can be forcibly exhausted, and the door 19 When the fan 33 is rotated in the reverse direction with the opening 15 opened, the cold air from the outside can be guided into the tank housing box 24, and the urea aqueous solution can be quickly lowered to an appropriate temperature. .

  In each of the above-described embodiments, the following can also be performed.

(1) The tank accommodating chamber 18 may be provided so as to contact the upper surface plate 11 of the counterweight 9, and the opening 15 may be provided on the upper surface of the counterweight 9.

(2) By providing the urea water tank 20 in the counterweight 9, a heat insulating effect can be obtained by thick plate materials such as the weight adjusting material 14 and the front plate 13, and therefore the heat insulating material 23 is not always necessary.

(3) If the urea water tank 20 itself has a double structure, the tank storage box 24 is not necessarily required.

(4) The heat insulating material 23 may be provided between the tank storage chamber 18 and the tank storage box 24, or between the tank storage box 24 and the urea water tank 20, and when the tank storage box 24 is not provided. The tank housing chamber 18 and the urea water tank 20 are provided.

(5) The temperature detector 30 may be provided in any of the tank storage chamber 18, the tank storage box 24, and the urea water tank 20.

1 is a plan view of a hydraulic excavator to which an arrangement structure of a liquid reducing agent tank for a NOx reduction catalyst of a construction machine according to the present invention is applied. It is a perspective view which shows the internal structure of the counterweight which shows 1st Embodiment of the arrangement structure of the liquid reducing agent tank for NOx reduction catalysts of the construction machine of this invention. It is the sectional view on the AA line in FIG. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is CC sectional view taken on the line in FIG. FIG. 4 is an enlarged view of a main part corresponding to FIG. 2 showing a second embodiment of the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to the present invention. FIG. 10 is an enlarged view of a main part corresponding to FIG. 2 showing a third embodiment of the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to the present invention.

Explanation of symbols

2; revolving body 5; engine 8; machine room 9; counterweight 10; rear plate 11; upper plate 12; lower plate 13; front plate 14; weight adjusting material 15; opening 16; space)
17; Partition plate (partition member)
18; Tank storage chamber 19; Door (lid member)
20; urea water tank (liquid reducing agent tank)
21; Cap 22; Supply port 23; Heat insulating material 24; Tank storage box 25 and 27; Convex part 26 and 28; Concave part 29; Communication hole (communication opening part)
30; temperature detector 31; louver 32; control device 33; fan

Claims (6)

A counterweight provided on the body frame;
A liquid reducing agent tank housing space provided in the counterweight and having an opening in a rear plate or an upper plate constituting the counterweight;
A tank accommodation chamber formed by being separated from a weight adjusting material filled in the counterweight by a partition member provided in the tank accommodation space;
A lid member for closing and opening the tank storage chamber;
A liquid reducing agent tank provided in the tank housing chamber;
Fixing means between the tank housing chamber and the liquid reducing agent tank;
An arrangement structure of a liquid reducing agent tank for a NOx reduction catalyst of a construction machine, characterized by comprising: In the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to claim 1,
An arrangement structure of a liquid reducing agent tank for NOx reduction catalyst, wherein a tank containing box made of a material that does not react with the liquid reducing agent for NOx reduction catalyst is provided between the tank storage chamber and the liquid reducing agent tank. . In the arrangement structure of the liquid reducing agent tank for the NOx reduction catalyst of the construction machine according to claim 1 or 2,
The fixing means is configured by fitting a concave portion and a convex portion provided along the longitudinal direction of the liquid reducing agent tank and the tank storage chamber or the tank storage box. Arrangement structure of liquid reducing agent tank for catalyst. In the arrangement structure of the liquid reducing agent tank for NOx reduction catalyst of the construction machine according to any one of claims 1 to 3,
A heat insulating material between the tank storage chamber and the liquid reducing agent tank, between the tank storage chamber and the tank storage box, or between the tank storage box and the liquid reducing agent tank. An arrangement structure of a liquid reducing agent tank for NOx reduction catalyst. In the arrangement structure of the liquid reducing agent tank for the NOx reduction catalyst of the construction machine according to any one of claims 1 to 4,
A temperature detection device for detecting any temperature in the tank storage chamber, the tank storage box, or the liquid reducing agent tank;
A communication opening communicating the tank storage chamber with the outside;
A movable louver that opens and closes the communication opening;
An arrangement structure of a liquid reducing agent tank for a NOx reduction catalyst, comprising: a control device that controls the movable louver based on a temperature signal from the temperature detection device. In the arrangement structure of the liquid reducing agent tank for the NOx reduction catalyst of the construction machine according to any one of claims 1 to 4,
A temperature detection device for detecting the temperature of any of the tank storage chamber, the tank storage box, and the liquid reducing agent tank;
A communication opening communicating the tank storage chamber with the outside;
A fan for discharging the air in the tank housing chamber to the outside or introducing the external air into the tank housing chamber;
An arrangement structure of a liquid reducing agent tank for NOx reduction catalyst, comprising a control device for controlling the fan based on a temperature signal from the temperature detection device.