JP2011064133A - Construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need to secure an exclusive installation space for a liquid reductant tank, and to install the tank under an appropriate temperature condition where there is no risk of freezing of liquid reductant. <P>SOLUTION: In a construction machine composed to reduce and eliminate nitrogen oxide in exhaust gas from an engine by using liquid reductant, a liquid reducing agent tank 19 storing liquid reductant is provided in an exhaust duct 20 discharging air in an engine room 10 to an outside under conditions where direct sunlight is cut off by the duct 20 and an exhaust passage 20a is secured in the duct 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a construction machine equipped with a system for reducing and purifying nitrogen oxide (NOx) in exhaust gas using a liquid reducing agent.

  As an exhaust gas purification system for construction machinery, a technique for promoting a reduction reaction by supplying a liquid reducing agent such as urea water to the upstream side of a reduction catalyst provided in a muffler is known.

  Since this liquid reducing agent crystallizes or freezes at low temperatures and deteriorates at high temperatures, it must be stored in a certain temperature range.

  With regard to the installation position of the liquid reducing agent tank for storing the liquid reducing agent, a technique in which the tank is installed in an openable and closable tool storage box provided in the upper swing body near the fuel tank (see Patent Document 1). A known technique 1) and a technique in which the tank is installed in an engine room, near a heat generating hydraulic device, in a cabin or the like (see Patent Document 2; known technique 2) are proposed. Yes.

JP 2008-240676 A JP 2003-20936 A

  However, according to the known techniques 1 and 2, both require a dedicated space for installing the liquid reducing agent tank. There was a problem of being forced to shrink.

  In addition, in the prior art 1, since only the radiant heat from the fuel tank that does not increase so much is used as a heat source for heating, the heating effect is hardly obtained, and the liquid reducing agent may be frozen at the time of cold.

  Accordingly, the present invention provides a construction machine that does not require a dedicated installation space for the liquid reducing agent tank and that can be installed at an appropriate temperature without fear of freezing of the liquid reducing agent. To do.

  The invention according to claim 1 includes an engine room in which the engine is housed, an exhaust duct for discharging the air in the engine room to the outside, and a liquid reducing agent tank for storing the liquid reducing agent, and exhaust gas from the engine In a construction machine configured to reduce and purify nitrogen oxides in the liquid reductant tank using the liquid reductant in the liquid reductant tank, the liquid reductant tank is blocked from the direct sunlight by the duct in the exhaust duct. In addition, an exhaust passage for exhausting the air in the engine room to the outside is provided in a state where it is secured in the duct.

  According to a second aspect of the present invention, in the configuration of the first aspect, the liquid reducing agent tank includes a liquid reducing agent supply port on an upper surface, and the liquid reducing agent tank is close to the upper surface portion of the exhaust duct. In addition to being provided in the same duct in the state, an opening / closing lid for replenishing the liquid reducing agent from the outside is provided in a portion facing the replenishing port in the upper surface portion of the exhaust duct.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, a liquid reducing agent tank is provided on the opposite side with the one side in a direction perpendicular to the flow of exhaust gas in the exhaust duct as the exhaust passage.

  According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, a partition plate that restricts a contact area between the exhaust gas passing through the exhaust passage and the liquid reducing agent tank at a boundary between the exhaust passage and the liquid reducing agent tank. It is provided along the flow of exhaust.

  According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, the guide member that guides the air in the engine room to the exhaust passage in the exhaust duct is directly connected to the sound generated in the engine room. It is provided in a state where it also serves as a shielding member for preventing it from passing through the duct and exiting from the tip opening.

  According to the present invention, since the liquid reducing agent tank is installed in the exhaust duct originally provided as a passage for air from the engine room to the outside, a new dedicated space for installing the tank becomes unnecessary.

  Therefore, particularly in a small construction machine, there is no adverse effect of being forced to change the device layout or reduce the device size.

Also, the liquid reducing agent tank
(A) Protect from direct sunlight by exhaust duct,
(B) Because it is installed in a state where it is heated by slightly hot air discharged from the engine room, the liquid reducing agent should not be too high, too low, and stored in a favorable temperature environment with little change. Can do.

  That is, overheating (deterioration of performance) of the liquid reducing agent and freezing when cold can be reliably prevented.

  In addition, since it is concealed in the duct, tank damage due to contact with foreign objects can be prevented, deterioration of the tank due to weathering, etc. can be suppressed, and replenishment when the top surface of the duct is used as a scaffold during maintenance work The tank including the mouth does not become an obstacle.

  According to the invention of claim 2, since the replenishing port of the liquid reducing agent tank is brought close to the upper surface of the duct and the opening / closing lid for replenishment is provided in the duct part facing the replenishing port, the liquid reducing agent can be easily removed from the outside. Can be replenished.

  Here, when the liquid reducing agent is replenished with a replenishing container such as a polytank, the replenishing operation is further facilitated since the replenishing operation can be performed with the duct upper surface as a scaffold and the container weight left on the duct upper surface.

  By the way, if the machine is operated continuously for a long time, the exhaust temperature from the engine room also rises, so the temperature of the liquid reducing agent may rise more than necessary particularly in summer.

  In this regard, according to the third and fourth aspects of the present invention, since one side of the exhaust duct in the direction orthogonal to the flow of exhaust is used as the exhaust passage, and the liquid reducing agent tank is provided on the opposite side, By limiting the contact surface only to the side facing the exhaust passage, an excessive temperature rise can be avoided.

  Further, since the exhaust passage is formed on one side, the ventilation resistance can be minimized and the necessary ventilation (exhaust) performance can be ensured.

  According to the invention of claim 4, since the partition plate for limiting the contact area between the exhaust and the tank is provided at the boundary between the exhaust passage and the liquid reducing agent tank, the effect of suppressing the temperature increase of the liquid reducing agent is enhanced. .

  On the other hand, according to the invention of claim 5, since the guide member for guiding the air in the engine room to the exhaust passage in the exhaust duct is provided, the flow of exhaust can be made smooth and the ventilation resistance can be further reduced.

  In addition, this guide member also functions as a shielding member that prevents so-called direct sound in which sound generated in the engine room is directly discharged to the outside through the exhaust duct.

  That is, according to the third to fifth aspects of the present invention, it is possible to prevent all the adverse effects that can occur by installing the liquid reducing agent tank in the exhaust duct.

It is the schematic side view which notched some excavators which concern on embodiment of this invention. It is the schematic plan view which notched a part of the shovel. It is a perspective view of the upper revolving body of the shovel. It is the perspective view which expanded a part of FIG. It is the VV line expanded sectional view of FIG. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5.

  An embodiment of the present invention will be described with reference to the drawings.

  The embodiment is applied to an excavator.

(I) Basic Configuration As shown in FIGS. 1 to 3, the excavator is mounted on a crawler-type lower traveling body 1 so that an upper swing body 2 can swing around a vertical axis that is perpendicular to the ground. A work attachment 6 including a boom 3, an arm 4, and a bucket 5 is attached to the front portion of the upper swing body 2.

  The upper swing body 2 is provided with a cabin 8 on the front left side of the upper frame 7 serving as a base, and a counterweight 9 on the rear end, and an engine room 10 on the rear (front of the counterweight 9). Yes.

  In the engine room 10, an engine 11 as a power source and devices (such as a hydraulic pump 12 and a heat exchanger (not shown)) around the engine are installed in the left-right direction.

  In this specification, “front-rear” and “left-right” refer to directions viewed from an operator seated in the cabin 8.

  A bonnet 13 is provided on the upper surface of the engine room 10 so as to be openable and closable with the rear side as a fulcrum. The bonnet 13 is opened to perform maintenance on the engine 11 and others from the upper surface side of the engine room.

  On the other hand, a fuel tank 14 and a hydraulic oil tank 15 are arranged side by side on the front right side of the engine room 10, and a front cover that covers a device room in which control valves and the like are installed in front of both tanks 14, 15. 16 is provided.

  On the upper surface side of the front cover 16, an ascending / descending staircase 17 that rises toward the bonnet 13 is formed integrally with the cover 16, and an operator climbs the ascending / descending staircase 17 from the front of the machine and above the engine room. The bonnet 13 can be opened and closed and maintenance work can be performed.

  In FIG. 2, reference numeral 18 denotes a boom foot pin that serves as a hoisting fulcrum of the boom 3 constituting the work attachment 6.

(II) Configuration Regarding Installation of Liquid Reductant Tank 19 A rectangular tubular exhaust duct 20 for discharging the air in the engine room 10 to the outside protrudes forward on the front side of the substantially central portion of the engine room 10, and The front end is provided with an opening as an exhaust port.

  The upper surface of the exhaust duct 20 is a part of an access passage for maintenance reaching the upper part of the engine room together with the upper surfaces of the ascending / descending stairs 17, the fuel tank 14 and the hydraulic oil tank 15, and also serves as a scaffold for maintenance work. Yes.

  The liquid reductant tank 19 has a replenishing port 19a for replenishing the liquid reductant on the upper surface, the replenishing port 19a is close to the upper surface of the exhaust duct 20, and the entire tank is It is installed in the exhaust duct 20 in a state of being covered from four rounds.

  In this case, one side (left side) in the direction perpendicular to the flow of exhaust gas in the exhaust duct 20 is used as the exhaust passage 20a, and the liquid reducing agent tank 19 is installed on the opposite side (right side).

  Further, a supply opening 21 and an opening / closing lid 22 for opening and closing the opening are provided at a portion of the upper surface of the exhaust duct 20 facing the supply port 19a, and the opening / closing lid 22 is opened as shown by a two-dot chain line in FIG. Thus, the liquid reducing agent can be replenished into the liquid reducing agent tank 19 from the outside (above) through the replenishing port 19a.

  Further, the contact area between the exhaust gas passing through the exhaust passage 20a and the left side surface of the liquid reducing agent tank 19 is limited at the boundary between the exhaust passage 20a and the liquid reducing agent tank 19 in the exhaust duct 20 as shown by an arrow in FIG. A partition plate 23 is provided along the flow of exhaust (for example, as shown in FIGS. 5 and 6, which is limited to about half the area of the left side surface of the tank).

  Further, as shown in FIG. 6, a U-shaped guide member 24 for smoothly guiding the air in the engine room 10 to the exhaust passage 20a in the exhaust duct 20 includes an inlet portion (in the engine room 10) of the exhaust passage 20a. It is provided at the exit part).

  The guide member 24 is provided at a position and range that shields the engine room 10 from being viewed directly when viewed from the outlet side of the exhaust passage 20a.

  That is, the guide member 24 also serves as a shielding member that prevents engine noise and other sounds generated in the engine room 10 from passing directly through the exhaust duct 20 to the outside through the opening at the front end.

  In addition, you may form the partition plate 23 and the guide member 24 integrally in series.

  Thus, since the liquid reducing agent tank 19 is installed in the exhaust duct 20 originally provided as a passage for air from the engine room 10 to the outside, a new dedicated space for installing the tank 19 is provided. It becomes unnecessary.

  Accordingly, there is no adverse effect that the equipment layout is changed or the equipment size is forced to be reduced particularly in a small construction machine.

Further, the liquid reducing agent tank 19 is
(A) Protect from direct sunlight by the exhaust duct 20,
(B) Since it is installed in a state where it is heated by the slightly hot air discharged from the engine room 10, the liquid reducing agent is not too high, not too low, and is stored in a favorable temperature environment with little change. be able to.

  That is, overheating (deterioration of performance) of the liquid reducing agent and freezing when cold can be reliably prevented.

  Further, since it is concealed in the duct 20, it is possible to prevent the liquid reducing agent tank 19 from being damaged by contact with foreign matter, to suppress the deterioration of the tank 19 due to weathering and the like, and to use the upper surface of the duct as a scaffold during maintenance work. The liquid reducing agent tank 19 including the supply port 19a does not become an obstacle.

  On the other hand, the replenishing port 19a of the liquid reducing agent tank 19 is brought close to the upper surface of the duct, and the opening / closing lid 22 for replenishment is provided in the duct portion facing the replenishing port 19a. be able to.

  Here, when the liquid reducing agent is replenished with a replenishing container such as a polytank, the replenishing operation is further facilitated since the replenishing operation can be performed with the duct upper surface as a scaffold and the container weight left on the duct upper surface.

  In addition, according to the embodiment, the following effects can be obtained.

  (A) Since one side (left side) in the direction orthogonal to the flow of exhaust gas in the exhaust duct 20 is the exhaust passage 20a and the liquid reducing agent tank 19 is provided on the opposite side, the contact surface of the liquid reducing agent tank 19 with the exhaust is provided. Excessive temperature rise can be avoided by limiting only to the side facing the exhaust passage 20a.

  (B) Since the exhaust passage 20a is formed on the left side of the duct, the ventilation resistance can be minimized and the necessary ventilation (exhaust) performance can be ensured.

  (C) Since the partition plate 23 for limiting the contact area between the exhaust gas and the tank 19 is provided at the boundary between the exhaust passage 20a and the liquid reducing agent tank 19, the effect of suppressing the temperature rise of the liquid reducing agent is enhanced.

  According to the inventor's experiment, the partition plate 23 is not provided under the condition that the exhaust temperature from the exhaust duct 20 is 70 ° C. to 80 ° C. at the duct inlet and the liquid reducing agent tank 19 is full (20 liters). In some cases, it was found that the liquid reducing agent in the tank was kept at 50 ° C. to 60 ° C., and when the partition plate 23 covered about half of the area on the left side of the tank, it was kept at 40 ° C. to 50 ° C.

  (D) Since the guide member 24 for guiding the air in the engine room 10 to the exhaust passage 20a is provided, the flow of exhaust can be made smooth and the ventilation resistance can be further reduced.

  In addition, the guide member 24 can prevent direct sound from the engine room.

  In this way, it is possible to prevent all the harmful effects that can occur by installing the liquid reducing agent tank 19 in the exhaust duct 20.

Other embodiments
(1) In the above embodiment, the liquid reducing agent tank 19 is provided on the right side in the exhaust duct 20, but it may be provided on the left side or in the center.

  (2) In a situation where there is a possibility that the temperature of the liquid reducing agent may increase excessively due to a small capacity of the liquid reducing agent tank 19 or a high exhaust temperature from the engine room 10, at least a part of the tank 19 is removed. Independent tank chambers that are covered with a heat insulating material or closed in the exhaust duct 20 may be defined.

  (3) The present invention is not limited to the excavator, and can be applied to other construction machines such as a dismantling machine and a crusher configured with the excavator as a base.

DESCRIPTION OF SYMBOLS 10 Engine room 19 Liquid reducing agent tank 19a Supply port 20 Exhaust duct 20a Exhaust passage 22 Opening / closing lid 23 Partition plate 24 Guide member

Claims (5)

  An engine room in which the engine is housed, an exhaust duct that discharges air in the engine room to the outside, and a liquid reductant tank that stores a liquid reductant, the nitrogen oxide in the exhaust gas from the engine In the construction machine configured to reduce and purify using the liquid reducing agent in the liquid reducing agent tank, the liquid reducing agent tank is blocked in the exhaust duct, the direct sunlight is blocked by the duct, and the engine room A construction machine characterized in that an exhaust passage for exhausting the air inside is secured in the duct.   The liquid reducing agent tank is provided with a liquid reducing agent supply port on the upper surface, and the liquid reducing agent tank is provided in the duct in a state where the supply port is close to the upper surface portion of the exhaust duct. The construction machine according to claim 1, wherein an opening / closing lid for replenishing the liquid reducing agent from the outside is provided at a portion facing the replenishing port.   3. The construction machine according to claim 1, wherein a liquid reducing agent tank is provided on the opposite side with one side in a direction orthogonal to the flow of exhaust gas in the exhaust duct as the exhaust passage.   4. The construction according to claim 3, wherein a partition plate for restricting a contact area between the exhaust gas passing through the exhaust passage and the liquid reducing agent tank is provided along a flow of the exhaust gas at a boundary between the exhaust passage and the liquid reducing agent tank. machine.   The guide member that guides the air in the engine room to the exhaust passage in the exhaust duct also serves as a shielding member that prevents sound generated in the engine room from passing directly through the exhaust duct to the outside through the front end opening. The construction machine according to claim 1, wherein the construction machine is provided in a state.

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