JP5855557B2 - Construction machinery - Google Patents

Description

  The present invention relates to a construction machine having a tank in which a liquid reducing agent is stored.

  Conventionally, construction machinery such as a hydraulic excavator equipped with a diesel engine has an exhaust gas treatment device installed in the exhaust system of the diesel engine in order to comply with high-order exhaust gas regulations. It is released into the atmosphere through a NOx reduction catalyst provided on the side.

  Conventionally, as this kind of exhaust gas treatment device, a urea selective reduction type NOx treatment device using a urea aqueous solution (liquid reducing agent) is often adopted, and the urea aqueous solution is stored in a metal or resin liquid reducing agent tank. ing. Further, the liquid reducing agent tank is connected to the exhaust pipe by a liquid reducing agent supply pipe, and is configured so that the urea aqueous solution in the liquid reducing agent tank can be supplied to the exhaust pipe by the liquid reducing agent supply pump (for example, Patent Document 1).

  Further, in this type of exhaust gas treatment apparatus, a configuration is known in which an injector for injecting an aqueous urea solution is provided in an exhaust pipe, and in order to cool the injector, engine cooling water is extracted and passed through the injector (for example, a patent) Reference 2).

JP 2003-20936 JP JP 2012-7511

  However, in the configuration disclosed in Patent Document 2 described above, the cooling water of the engine is extracted and returned to the engine via the injector. However, since the cooling water passing through the injector becomes considerably high temperature, If it is returned to the engine as it is, the heat balance will be adversely affected (and may cause engine overheating).

  Then, an object of this invention is to provide the construction machine which can reduce the bad influence which has on a heat balance.

In order to achieve the above object, according to one aspect of the present invention, an engine,
A liquid reducing agent tank in which the liquid reducing agent is stored;
An injection device that is provided in an exhaust path of the engine and injects the liquid reducing agent supplied from the liquid reducing agent tank to the exhaust from the engine;
A refrigerant flow path through which a refrigerant for cooling the engine flows, wherein the refrigerant is taken out from the engine and guided to the injection device, and the refrigerant guided to the injection device is returned to the engine. A single refrigerant flow path;
A heat dissipating means provided in a flow path portion in the refrigerant flow path of the first system, the flow path portion returning the refrigerant guided to the injection device into the engine ;
A refrigerant flow path of a second system through which the refrigerant of the engine flows, wherein the refrigerant is taken out from the engine and led to the liquid reducing agent tank, and the refrigerant led to the liquid reducing agent tank is A second system refrigerant flow path to be introduced into the flow path portion of the first system refrigerant flow path ,
A construction machine is provided in which the heat dissipating means is arranged closer to the injection device than the refrigerant introduction position from the refrigerant flow path of the second system in the flow path portion .

  ADVANTAGE OF THE INVENTION According to this invention, the construction machine which can reduce the bad influence which has on heat balance is obtained.

It is a side view which shows the hydraulic shovel as an example of a construction machine. It is a top view which shows roughly the rear part of an upper revolving body by upper surface view. FIG. 5 is a perspective view schematically showing an installed state of a liquid reducing agent tank 70. It is a figure which shows an example of the arrangement | positioning method of the heat radiator 300 with an example of the cooling water path | route and urea water path | route relevant to the diesel engine 8 and the tank 70 for liquid reducing agents. It is a figure which shows an example of the connection aspect of the pipe part of the return direction in the 1st pipe 120 in the duct 81 of a water pump.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing a hydraulic excavator as an example of a construction machine.

  As shown in FIG. 1, an upper swing body 2 is mounted on the lower traveling body 1 so as to be swingable, and a cab 3 is provided on one front side of the upper swing body 2. In addition, the boom 4 is pivotally attached to the front center portion of the upper swing body 2 so that the boom 4 can be raised and lowered, and an arm 5 is connected to the distal end portion of the boom 4 so as to be rotatable up and down. A bucket 6 is attached so as to be rotatable up and down. The excavation attachment may be another attachment such as a breaker or a crusher.

  FIG. 2 is a plan view schematically showing the rear part of the upper swing body in a top view.

  As shown in FIG. 2, an engine room 7 is formed at the rear of the upper swing body 2, and a diesel engine 8 is installed in the engine room 7. A cooling fan 12 is provided in front of the diesel engine 8 (front side in FIG. 2), and a heat exchanger unit 13 including a radiator and the like is installed in front of the cooling fan 12.

  Further, an exhaust pipe 9 is connected to the diesel engine 8, and an exhaust gas treatment device 10 is installed on the downstream side of the exhaust pipe 9 in order to comply with higher-order exhaust gas regulations. As the exhaust gas treatment device 10, a urea selective reduction type NOx treatment device using an aqueous urea solution (liquid reducing agent) is adopted. The exhaust gas treatment apparatus 10 includes an SCR (Selective Catalytic Reduction) catalyst and an oxidation catalyst (DOC: Diesel Oxidation Catalyst) for burning unburned fuel contained in PM (Particular Matter) in addition to a dosing module 202 described later. Good.

  FIG. 3 is a perspective view schematically showing an installed state of the liquid reducing agent tank 70.

  As shown in FIG. 3, a pair of left and right boom mounting support brackets 17 </ b> L and 17 </ b> R are erected on the front portion of the revolving frame 14 of the upper revolving structure 2. In addition, a fuel tank 18 and a sump tank 19 are arranged in series on the rear side of the support bracket 17L. A liquid reducing agent tank 70 is disposed on the front side of the fuel tank 18. Accordingly, in the illustrated example, the liquid reducing agent tank 70, the fuel tank 18, and the sump tank 19 are arranged adjacently in order from the front. The order of the fuel tank 18 and the sump tank 19 is arbitrary. The fuel tank 18 and the sump tank 19 may be arranged side by side in the width direction. The liquid reducing agent tank 70 may be formed of a resin material. An aqueous urea solution is stored in the liquid reducing agent tank 70. The liquid reducing agent tank 70 is disposed such that the front side surface is located behind the holes 172L and 172R of the boom support brackets 17L and 17R.

  FIG. 4 is a diagram illustrating an example of a method of arranging the radiator 300 together with an example of a cooling water path and a urea water path related to the diesel engine 8 and the liquid reducing agent tank 70.

  The liquid reducing agent tank 70 is connected to the exhaust gas treatment device 10 via the first liquid reducing agent supply pipe 112, the supply pump module 200, the second liquid reducing agent supply pipe 114, and the dosing module 202. Urea in the liquid reducing agent tank 70 is pumped out by the supply pump module 200 via the first liquid reducing agent supply pipe 112 and introduced into the dosing module 202 via the second liquid reducing agent supply pipe 114. The dosing module 202 is an example of an injection device, and includes an injector that injects urea to be introduced into the exhaust pipe 9. The dosing module 202 is provided in the exhaust pipe 9. Therefore, the dosing module 202 can become very hot due to the heat of the exhaust gas passing through the exhaust pipe 9.

  In the diesel engine 8, a cooling path (not shown) is formed by cooling water (an example of a refrigerant). The cooling water may be, for example, LLC (Long Life Coolant). The cooling path in the diesel engine 8 (that is, the parts to be cooled, the cooling water circulation method, etc.) may be arbitrary. Typically, the cooling path in the diesel engine 8 passes through the heat exchanger unit 13 including a radiator and the like.

  Cooling water taken out from the cooling path in the diesel engine 8 may be circulated in the liquid reducing agent tank 70 via a second-system refrigerant flow path for preventing the liquid reducing agent from freezing. Specifically, the second pipe 110 branched from the cooling path in the diesel engine 8 is passed through the liquid reducing agent tank 70. The cooling water in the diesel engine 8 is circulated through the second pipe 110. The cooling water in the second pipe 110 taken out from the diesel engine 8 has a flow velocity in the direction toward the liquid reducing agent tank 70 by a water pump (not shown) of the diesel engine 8. The second pipe 110 may be provided with a coolant control valve 204 on the upstream side (diesel engine 8 side) of the liquid reducing agent tank 70. The second pipe 110 passes through the liquid reducing agent tank 70, exits from the liquid reducing agent tank 70, passes through the supply pump module 200, exits from the supply pump module 200, and will be described later with a first pipe 120 (return). Directional pipe part). The coolant control valve 204 is controlled by, for example, a controller (not shown), and is changed from the closed state to the open state when the necessity of preventing the liquid reducing agent in the liquid reducing agent tank 70 from being frozen.

  The cooling water taken out from the cooling path in the diesel engine 8 is circulated through the dosing module 202 via the first system refrigerant flow path for cooling the dosing module 202. Specifically, the first pipe 120 branched from the cooling path in the diesel engine 8 is passed through the dosing module 202. The first pipe 120 passes through the dosing module 202, exits the dosing module 202, and is connected to a cooling path in the diesel engine 8. The cooling water taken out from the cooling path in the diesel engine 8 flows through the dosing module 202 while passing through the first pipe 120, thereby depriving the dosing module 202 of heat (ie, cooling the dosing module 202). ). Therefore, the cooling water coming out from the dosing module 202 can be in a very high temperature state. In addition, the arrangement | positioning aspect of the 1st pipe 120 in the dosing module 202 may be arbitrary.

  In the illustrated example, the first pipe 120 is provided so as to branch from the second pipe 110 at the branch portion 130. However, the first pipe 120 may be branched from the cooling path in the diesel engine 8 regardless of the second pipe 110. However, in any case, the cooling water in the first pipe 120 taken out from the diesel engine 8 has a flow velocity in the direction toward the dosing module 202 by a water pump (not shown) of the diesel engine 8.

  A radiator 300 is provided on the return side of the first pipe 120 (between the dosing module 202 and the diesel engine 8). Therefore, the cooling water passing through the dosing module 202 is cooled by the radiator 300 and then returned to the cooling path in the diesel engine 8. The radiator 300 may have any configuration, and may be in the form of a small radiator, for example. The heat dissipation capability of the radiator 300 is determined so that the high-temperature cooling water returned from the dosing module 202 into the diesel engine 8 is sufficiently cooled to a temperature that does not adversely affect the heat balance.

  The heat radiator 300 is preferably arranged in the vicinity of the dosing module 202 as shown in FIG. Thereby, since the heat radiator 300 can cool the cooling water (high-temperature state cooling water) immediately after coming out of the dosing module 202, the cooling efficiency can be increased. Specifically, the radiator 300 may be disposed closer to the dosing module 202 than the connection portion 132 of the first pipe 120 (pipe portion in the return direction) with the second pipe 110. As a result, the radiator 300 can cool the cooling water immediately after coming out of the dosing module 202 before being mixed with the cooling water introduced from the second pipe 110, so that the cooling efficiency can be improved. . However, the radiator 300 may be disposed closer to the diesel engine 8 than the connection portion 132 of the first pipe 120 (pipe portion in the return direction) to the second pipe 110.

  As described above, according to the configuration shown in FIG. 4, the radiator 300 is provided in the portion between the dosing module 202 and the diesel engine 8 in the first pipe 120 (the pipe portion in the return direction from the dosing module 202 to the diesel engine 8). Thus, after cooling the high-temperature cooling water from the dosing module 202 into the diesel engine 8 with the radiator 300, the cooling water can be returned to the diesel engine 8. Thereby, it is possible to prevent the heat balance from being deteriorated due to the cooling water returned from the dosing module 202 into the diesel engine 8.

  In the example shown in FIG. 4, the second pipe 110 is connected to the pipe portion in the return direction of the first pipe 120. That is, the cooling water in the second pipe 110 from the supply pump module 200 is introduced into the pipe portion in the return direction of the first pipe 120 and then returned into the diesel engine 8. However, the cooling water in the second pipe 110 from the supply pump module 200 may be returned directly into the diesel engine 8 without being introduced into the cooling water in the first pipe 120. That is, the cooling water introduced into the water pump through the second pipe 110 and the cooling water introduced into the water pump through the first pipe 120 may be mixed in the water pump. In this configuration, the connecting portion 132 is located in the water pump.

  In the configuration shown in FIG. 5, the pipe portion in the return direction of the first pipe 120 is connected to the duct 81 of the water pump. The cooling water returned into the diesel engine 8 is circulated in the diesel engine 8 by a water pump, and after cooling each component in the diesel engine 8, it is cooled by a heat exchanger unit 13 including a radiator and the like. The cooling water cooled by the heat exchanger unit 13 is returned to the water pump in the diesel engine 8. The cooling water taken out from the diesel engine 8 through the pipe portion 110B of the supply system of the second pipe 110 may be cooling water at any point in the diesel engine 8, but for example, each of the cooling water in the diesel engine 8 It may be cooling water after cooling the components (cooling water before being cooled by the heat exchanger unit 13) or cooling water after being cooled by the heat exchanger unit 13. In any case, the cooling water taken out from the diesel engine 8 through the pipe portion 110B of the supply system of the second pipe 110 is transferred to the dosing module 202 by the first pipe 120 via the branch portion 130 as described above. Supplied.

  Next, referring to FIG. 2 again, a preferred arrangement example of the radiator 300 will be described.

  As shown in FIG. 2, the radiator 300 is preferably disposed between the diesel engine 8 and the counterweight 90 in the front-rear direction. Thereby, the radiator 300 can be arranged by efficiently using the limited space at the rear of the construction machine 1. The counterweight 90 is a heavy object for balancing the weight with respect to the weight of the front part of the construction machine 1 (particularly the weight of the attachment). More specifically, the radiator 300 may be attached to a house frame (a frame that defines the engine room 7) near the lower part of the intercooler outlet pipe. Alternatively, the radiator 300 may be attached to the house frame near the lower part of the step (the step of defining a scaffold passed above the diesel engine 8).

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the second pipe 110 passes through the supply pump module 200, but may not pass through the supply pump module 200. That is, the second pipe 110 may fulfill the function of preventing the liquid reducing agent from freezing through the liquid reducing agent tank 70 without passing through the supply pump module 200. The second pipe 110 may be returned to the diesel engine 8 through the liquid reducing agent tank 70 after passing through the supply pump module 200. That is, the order in which the cooling water taken out from the diesel engine 8 passes through the supply pump module 200 and the liquid reducing agent tank 70 may be opposite to the above-described embodiment.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving body 3 Cab 4 Boom 5 Arm 6 Bucket 7 Engine room 8 Diesel engine 9 Exhaust pipe 10 Exhaust gas treatment device 12 Cooling fan 13 Heat exchanger unit 14 Turning frame 17L, 17R Boom support bracket 172L, 172R Hole 18 Fuel tank 19 Sump tank 70 Liquid reductant tank 81 Water pump duct 90 Counterweight 110 Second pipe 112, 114 Liquid reductant supply pipe 120 First pipe 130 Branching section 132 Connection section 200 Supply pump module 202 Dosing module 204 Coolant Control valve 300 Radiator

Claims (2)

Engine,
A liquid reducing agent tank in which the liquid reducing agent is stored;
An injection device that is provided in an exhaust path of the engine and injects the liquid reducing agent supplied from the liquid reducing agent tank to the exhaust from the engine;
A refrigerant flow path through which a refrigerant for cooling the engine flows, wherein the refrigerant is taken out from the engine and guided to the injection device, and the refrigerant guided to the injection device is returned to the engine. A single refrigerant flow path;
A heat dissipating means provided in a flow path portion in the refrigerant flow path of the first system, the flow path portion returning the refrigerant guided to the injection device into the engine ;
A refrigerant flow path of a second system through which the refrigerant of the engine flows, wherein the refrigerant is taken out from the engine and led to the liquid reducing agent tank, and the refrigerant led to the liquid reducing agent tank is A second system refrigerant flow path to be introduced into the flow path portion of the first system refrigerant flow path ,
The construction machine according to claim 1, wherein the heat dissipating means is disposed closer to the injection device than a position where the refrigerant is introduced from the refrigerant flow path of the second system in the flow path portion . The construction machine according to claim 1, wherein the heat dissipating means is disposed between the engine and a counterweight in the front-rear direction.

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