JP6402124B2 - Construction machine cooling system - Google Patents

Description

  The present invention relates to a cooling device for a construction machine that includes a cooling fan that is driven by an engine and generates wind that cools a radiator.

  FIG. 8 is a diagram showing an example of a conventional construction machine cooling apparatus. This prior art is a cooling device provided in a construction machine such as a dump truck, and cooling water is circulated in the engine 11 by driving a pump. As the output of the engine 11 increases, the temperature of the engine 11 increases. When the cooling water circulating in the engine 11 is heated and exceeds a certain temperature, a thermostat provided in the flow path in the engine 11 is opened, and this cooling water passes through the cooling water pipe 54 in the high-temperature radiator 40 and the low-temperature radiator 41. Circulate. The circulating cooling water is heat-exchanged between the radiators 40 and 41 and the outside air by the wind generated by the cooling fan 49, that is, the cooling air 200.

  The cooling fan 49 is connected to the output shaft of the engine 11, a transmission such as a belt or a gear (not shown), and the fan clutch 60, and the rotational speed of the cooling fan 49 is also defined according to the rotational speed of the engine 11. . The fan clutch 60 is ON / OFF controlled by the controller 50 according to the temperature of the cooling water detected by the temperature sensors 55 and 56 attached to the cooling water pipe 54 and a command from the outside.

  The high temperature radiator 40 is disposed closer to the cooling fan 49 than the low temperature radiator 41 and cools the cooling water of the engine 11. The low-temperature radiator 41 cools the intake gas compressed by the turbo. This type of prior art is disclosed in Patent Document 1.

JP 2000-186553 A

  In the cooling device including the radiators 40 and 41 and the cooling fan 49 shown in FIG. 8 and the like described above, the engine 11 is cooled so as not to exceed the allowable temperature even when the engine 11 operates at a maximum output for a certain period of time. Ability is required. For this reason, in the prior art, there was a problem that excessive cooling, that is, overcooling occurred during low-load operation. In addition, there is a problem that wasteful energy consumption is caused by operating the large cooling fan 49.

  In order to achieve the above-described problems, an object of the present invention is to provide a construction machine cooling apparatus capable of ensuring highly accurate cooling performance.

In order to achieve the above object, a cooling device for a construction machine according to the present invention includes a radiator, a cooling fan that is driven by an engine to generate wind that cools the radiator, and water cooled by the radiator is supplied to the engine. In a cooling device for a construction machine including a cooling water pipe to be supplied, and a fan clutch that connects and disconnects the cooling fan and an output shaft of the engine, the cooling water pipe is connected in series to the radiator upstream through the cooling water pipe, and from the radiator A downstream auxiliary radiator whose capacity is set small, an auxiliary fan which is provided separately from the cooling fan and generates wind for cooling the auxiliary radiator, a detection unit for detecting the operating state of the engine, and the detection depending on the operating state of said detected engine parts, one of the cooling fan and the auxiliary fan It is characterized by comprising a controller for performing a control process for selectively actuating the person.

  According to the construction machine cooling device of the present invention, the controller includes a cooling fan for cooling the radiator and an auxiliary fan for cooling the auxiliary radiator having a smaller capacity than the radiator according to the operating state of the engine detected by the detection unit. Since the control process for selectively operating one of them is performed, it is possible to ensure a highly accurate cooling performance according to the operating state of the engine. Thereby, this invention can suppress the overcooling at the time of the low load driving | running which was a concern with the prior art, and can prevent useless energy consumption.

It is a side view which shows the dump truck mentioned as an example of the construction machine provided with 1st Embodiment of the cooling device which concerns on this invention. It is a figure which shows the structure of 1st Embodiment of the cooling device which concerns on this invention. It is a figure which shows the correlation of the engine output set in the controller with which 1st Embodiment is provided, and engine calorific value. It is a figure which shows an example of the relationship between the operation time of the dump truck shown in FIG. 1, and an engine output. It is a flowchart which shows the process sequence in the controller with which 1st Embodiment is equipped. It is a flowchart which shows the process sequence in the controller with which 2nd Embodiment of this invention is equipped. It is a figure which shows the relationship between the temperature of the cooling water which flows through the cooling water pipe with which 2nd Embodiment is equipped, and control of a cooling fan and an auxiliary fan. It is a figure which shows an example of the cooling device of the conventional construction machine.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a construction machine cooling apparatus according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the construction machine provided with the cooling device according to the first embodiment is a dump truck 100, for example. In the dump truck 100, a body 4 for loading earth and sand is mounted on a frame 36, and the frame 36 and the body 4 are connected by a hoist cylinder 33. A front wheel 7, a rear wheel 8, a hydraulic oil tank 6, a fuel tank 5, and the like are attached to the frame 36 through mechanical parts (not shown).

  A traveling motor 10 that drives the rear wheel 8 and a speed reducer 9 that adjusts the rotational speed of the traveling motor 10 and the rear wheel 8 are housed in the rotating shaft portion of the rear wheel 8. Further, a deck 28 on which an operator can walk is attached to the frame 36.

  Mounted on the deck 28 are a cab 2 on which an operator is boarded to form an operation room of the dump truck 100, a control cabinet 1 in which various power devices are stored, and a plurality of grid boxes 3 that dissipate surplus energy as heat. Has been. At the front side position of the vehicle body, a ladder 37 is provided for the operator to move up and down with respect to the deck 28.

  An engine, a main generator, and the like are mounted on the portion hidden by the front wheel 7. Further, a handle and an accelerator pedal are installed in the cab 2, and these operating devices are connected to a hydraulic device via a shaft (not shown). By rotating the steering wheel to the left and right, the hydraulic steering piston is expanded and contracted, and by changing the angle of the front wheel 7, the traveling direction of the vehicle body during traveling is changed to the left and right.

  The first embodiment of the cooling device according to the present invention provided in the dump truck 100 includes the conventional configuration shown in FIG. That is, as shown in FIG. 2, the first embodiment also has a radiator composed of a high-temperature radiator 40 and a low-temperature radiator 41 and a cooling fan that is driven by the engine 11 and generates wind that cools the radiator, that is, the high-temperature radiator 40 and the low-temperature radiator 41. 49, a cooling water pipe 54 that supplies water cooled by the high-temperature radiator 40 and the low-temperature radiator 41 for cooling the cooling water of the engine 11 and cooling the compressed gas, and a controller 50.

  A fan clutch 60 that connects and disconnects the cooling fan 49 and the output shaft of the engine 11 is also provided. The main generator 12 is driven by the engine 11. Further, a temperature sensor 55 that detects the temperature of the heated water in the cooling water pipe 54 returned to the high-temperature radiator 40 and a temperature sensor 56 that detects the temperature of the heated water returned to the low-temperature radiator 41 are provided.

  As described above, the high temperature radiator 40 is disposed closer to the cooling fan 49 than the low temperature radiator 41 and cools the cooling water of the engine 11. The low-temperature radiator 41 cools the intake gas compressed by the turbo.

  This first embodiment is connected to the radiator via the cooling water pipe 54 and is provided separately from the auxiliary radiator having a capacity smaller than that of the radiator and the cooling fan 49, and generates auxiliary air for cooling the auxiliary radiator. A fan and a detection unit that detects the operating state of the engine 11 are provided. Further, the controller 50 performs a control process for selectively operating one of the cooling fan 49 and the auxiliary fan according to the operating state of the engine 11 detected by the detection unit.

  For example, the auxiliary radiator is connected to the high temperature radiator 40 via the cooling water pipe 54, and is connected to the first auxiliary radiator 42 having a capacity smaller than that of the high temperature radiator 40, and the low temperature radiator 41 via the cooling water pipe 54. The second auxiliary radiator 43 has a capacity smaller than that of the low-temperature radiator 41.

  The above-described auxiliary fan includes a first auxiliary fan 45 that generates a wind for cooling the first auxiliary radiator 42 and a second auxiliary fan 46 that generates a wind for cooling the second auxiliary radiator 43.

  Further, a first auxiliary motor 47 that drives the first auxiliary fan 45 and a second auxiliary motor 48 that drives the second auxiliary fan 46 are provided. The first auxiliary motor 47 and the second auxiliary motor 48 are driven by electricity generated by the main generator 12.

  In the first embodiment, the detection unit that detects the operating state of the engine 11 includes a detection unit that detects the output of the engine 11. The detection unit includes a torque sensor 58 that detects the engine torque Tr and a rotation sensor 57 that detects the rotational speed N of the engine 11.

  The first auxiliary radiator 42, the second auxiliary radiator 43, the first auxiliary fan 45, the second auxiliary fan 46, the first auxiliary motor 47, and the second auxiliary motor 48 are the high temperature radiator 40, the low temperature radiator 41, and the cooling fan 49. 1 is disposed in the heat exchanger chamber 39 shown in FIG. 1 disposed at the front side position where the wind is received when the dump truck 100 is traveling forward.

In the controller 50 described above, the correlation between the engine output and the engine heat generation amount shown in FIG. 3 is set. What is shown on the horizontal axis in FIG. 3 is as follows.
Ph: Engine output upper limit threshold P1: Engine output lower limit threshold Pav: Average engine output Pth: Output threshold set between average engine output Pav and engine output upper limit threshold Ph Further, the vertical axis shows the following: .
Qh: Heat generation amount upper limit threshold corresponding to engine output upper limit threshold Ph Q1: Heat generation amount lower limit threshold corresponding to engine output lower limit threshold P1 Qav: Average engine heat generation amount corresponding to average engine output Pav Qth: Average engine heat generation amount Qav and heat generation A calorific value threshold corresponding to the output threshold Pth, which is a value between the amount upper limit threshold Qh and the calorific value threshold Qth, can be achieved by driving the first auxiliary motor 47 and the second auxiliary motor 48 to achieve desired cooling. This is an expected value.

  As shown in FIG. 3, the engine heat generation amount is changed from the heat generation amount lower limit threshold value Q1 to the heat generation amount upper limit threshold value Qh so that the engine output is substantially proportional from the engine output lower limit threshold value P1 toward the engine output upper limit threshold value Ph. It is a functional relationship that gradually increases toward.

  FIG. 4 is a diagram showing an example of the relationship between the operation time of the dump truck 100 shown in FIG. 1 and the engine output. The dump truck 100 is used when carrying earth and sand or ore in an open pit mine, and reciprocates between a dumping place and a loading place.

  In FIG. 4, A is a point where movement starts from the dumping ground, B is a point arriving at the loading site, C is a point leaving the loading site, and D is a point arriving at the dumping site. Between B and C is a time during which the dump truck 100 stops (idling) in order to load earth and sand or ore into the dump truck 100 by a hydraulic excavator, a wheel loader or the like.

  The engine output upper limit threshold Ph is generated when accelerating by loading earth or sand or ore, or when accelerating on a steep slope. However, the average engine output Pav is usually less than or equal to half of the engine output upper limit threshold Ph, and the time during which the engine output becomes maximum is limited.

  An engine output that is twice the engine output during idling between B and C is set as an engine output lower limit threshold value P1. The engine heat generation amount at this time is the heat generation amount lower limit threshold Q1 as described above.

  Processing operations in the controller 50 provided in the first embodiment configured as described above will be described with reference to FIG.

[Step S1] When the engine key is turned ON, the engine torque Tr from the torque sensor 58 that detects the torque of the engine 11 and the engine speed N from the rotation sensor 57 that detects the speed of the engine 11 are input. Next, the process proceeds to step S2.

[Step S2] An engine output is calculated based on the engine torque Tr and the engine speed N, and the process proceeds to Step S3.

[Step S3] An engine heat generation amount Q corresponding to the calculated engine output is calculated from the correlation shown in FIG. 3, and the process proceeds to step S4.

[Step S4] It is determined whether the calculated calorific value Q is equal to or greater than a calorific value threshold Qth. When it is equal to or greater than Qth, the process proceeds to step S5. When smaller than Qth, the process proceeds to step S7.

[Step S5] An ON signal of the fan clutch 60 is output. As a result, the fan clutch 60 connects the output shaft of the engine 11 and the cooling fan 49, and the wind generated by the cooling fan 49, that is, a large amount of cooling air is supplied to the high-temperature radiator 40 and the low-temperature radiator 41. Cooling water for the engine 11 is cooled by the high-temperature radiator 40, and intake gas compressed by the turbo is cooled by the low-temperature radiator 41. Next, the process proceeds to step S6.

[Step S6] The OFF signals of the first auxiliary motor 47 and the second auxiliary motor 48 are output. As a result, the first auxiliary motor 47 and the first auxiliary fan 45 are stopped, and the first auxiliary radiator 42 is not cooled. Further, the second auxiliary motor 48 and the second auxiliary fan 46 are stopped, and the second auxiliary radiator 43 is not cooled.

  Thus, when the engine heat generation amount is equal to or greater than the heat generation amount threshold value Qth, the cooling water and the intake gas of the engine 11 are strongly cooled by the large flow rate of cooling air generated by the cooling fan 29 to ensure a desired cooling performance. be able to.

[Step S7] When the engine heat generation amount Q is smaller than the heat generation amount threshold value Qth, an OFF signal of the fan clutch 60 is output. As a result, the fan clutch 60 and the output shaft of the engine 11 are disconnected, and the cooling fan 49 stops. Next, the process proceeds to step S8.

[Step S8] It is determined whether the engine heat generation amount Q is equal to or less than a heat generation amount lower limit threshold Q1. When it is larger than the heat generation amount lower limit threshold Q1, the process proceeds to step S9. When it is less than or equal to the heat generation amount lower threshold Q1, the process proceeds to step S11.

[Step S9] Based on the correlation between the engine heat generation amount preset in the controller 50 and the rotation speed of the first auxiliary motor 47, the rotation speed of the first auxiliary motor 47 corresponding to the engine heat generation amount Q, and the first 2 Calculate the rotational speed of the auxiliary motor 48 and proceed to Step S10.

[Step S10] The drive of the first auxiliary motor 47 is controlled so that the calculated number of revolutions is obtained. In response to this, the first auxiliary fan 45 is operated, and the first auxiliary radiator 42 is cooled by the cooling air that suppresses the flow rate generated by the first auxiliary fan 45. Further, the driving of the second auxiliary motor 48 is controlled so that the calculated rotational speed is obtained. In response to this, the second auxiliary fan 46 operates, and the second auxiliary radiator 43 is cooled by the cooling air with the flow rate generated by the second auxiliary fan 46 suppressed.

  In this way, when the engine heat generation amount Q is smaller than the heat generation amount threshold value Qth and larger than the heat generation amount lower limit threshold value Q1, the cooling air that makes it easy to suppress the flow rate generated by the first auxiliary fan 45 and the second auxiliary fan 46. Thus, the cooling water of the engine 11 and the intake gas are cooled relatively weakly.

[Step S11] When the engine heat generation amount Q is equal to or less than the heat generation amount lower threshold Q1, control is performed to stop the first auxiliary motor 47 and the second auxiliary motor 48. Thereby, all of the cooling fan 49, the first auxiliary fan 45, and the second auxiliary fan 46 are stopped. That is, it is considered that the engine 11 is in an idle state, and the cooling water of the engine 11 and the intake gas are not cooled.

  After the processes of steps S6, S10, and S11, the processes of steps S1 to S11 are continuously executed. When the engine key is turned off, the process of the controller 50 ends.

  The cooling device according to the first embodiment configured as described above includes the controller 50 according to the engine output calculated based on the engine torque Tr detected by the torque sensor 58 and the rotation sensor 57 and the engine speed N. A cooling fan 49 that cools the high-temperature radiator 40 and the low-temperature radiator 41, a first auxiliary fan 45 that cools the first auxiliary radiator 42 that has a smaller capacity than the high-temperature radiator 40, and a second auxiliary radiator 43 that has a smaller capacity than the low-temperature radiator 41 The control process for operating one of the second auxiliary fans 46 that cools the engine, that is, the control process for operating the cooling fan 49 or the control process for operating the first auxiliary fan 45 and the second auxiliary fan 46 is performed. Thus, it is possible to ensure a highly accurate cooling performance corresponding to the 11 operating states. Thereby, 1st Embodiment can suppress the supercooling at the time of the low load used as engine output smaller than the output threshold value Pth, and can prevent useless consumption of energy.

  The first auxiliary fan 45 and the first auxiliary radiator 42, the second auxiliary fan 46 and the second auxiliary radiator 43 are effectively utilized by utilizing the dead space in the heat exchanger chamber 39 provided at the front side position of the vehicle body. Can be arranged.

  In the second embodiment of the cooling device according to the present invention, the detection unit that detects the operating state of the engine 11 includes a temperature sensor 55 that detects the temperature of the cooling water on the high-temperature radiator 40 side, and the cooling water on the low-temperature radiator 41 side. It consists of a temperature sensor 56 that detects the temperature. Accordingly, the controller 50 performs the processing operation shown in the flowchart of FIG. In addition, the point which a detection part consists of temperature sensors 55 and 56 and the other structure except the processing operation of the controller 50 are equivalent to 1st Embodiment shown in FIG.

  The processing operation of the controller 50 in the second embodiment will be described below with reference to FIG.

[Step S21] When the engine key is turned ON, the coolant temperature T1 on the high temperature radiator 40 side detected by the temperature sensor 55 and the coolant temperature T2 on the low temperature radiator 41 side detected by the temperature sensor 56 are input. Proceed to S22.

[Step S22] It is determined whether the coolant temperature T1 is equal to or higher than a first temperature threshold value Tth1 preset by the controller 50, or whether the coolant temperature T2 is equal to or higher than a second temperature threshold value Tth2 preset by the controller 50. If it is equal to or higher than the first temperature threshold Tth1 or equal to or higher than the second temperature threshold Tth2, the process proceeds to step S23. When the determination in step S22 is not satisfied, the process proceeds to step S25.

[Step S23] An ON signal of the fan clutch 60 is output. As a result, similarly to step S5 of FIG. 5 described above, the high-temperature radiator 40 and the low-temperature radiator 41 are cooled by the large-flow cooling air of the cooling fan 49, and the cooling water and intake gas of the engine 11 are strongly cooled.

[Step S24] The OFF signals of the first auxiliary motor 47 and the second auxiliary motor 48 are output. As a result, similarly to step S6 of FIG. 5 described above, the first auxiliary fan 45 and the second auxiliary fan 46 are stopped, and the first auxiliary radiator 42 and the second auxiliary radiator 43 are not cooled. The above processing is the state between A and B in FIG.

[Step S25] When the determination in step S22 is not satisfied, an OFF signal of the fan clutch 60 is output. As a result, the cooling fan 49 stops as in step S7 of FIG. Next, the process proceeds to step S26.

[Step S26] Based on the correlation between the temperature detected by the temperature sensors 55 and 56 preset in the controller 50 and the rotational speeds of the first auxiliary motor 47 and the second auxiliary motor 48, the temperature sensor 55 detects the temperature. The rotation speed of the first auxiliary motor 47 and the rotation speed of the second auxiliary motor 48 corresponding to the cooling water temperature T1 and the cooling water temperature T2 detected by the temperature sensor 56 are calculated, and the process proceeds to step S27.

[Step S27] The drive of the first auxiliary motor 47 and the second auxiliary motor 48 is controlled so that the calculated rotational speed is obtained. Accordingly, the first auxiliary radiator 42 is cooled by the first auxiliary fan 45 and the second auxiliary radiator 43 is cooled by the second auxiliary fan 46, as in step S10 of FIG. The process at this time is in a state in which the area between AB in FIG. 7 is removed.

  After the processes of steps S24 and S27, the processes of steps S21 to S27 are continued. When the engine key is turned off, the process of the controller 50 ends.

  In the cooling device according to the second embodiment configured as described above, the cooling fan 49 or the first auxiliary fan 45 and the second auxiliary fan 46 are operated by the control process of the controller 50 as in the first embodiment described above. In addition, it is possible to ensure a highly accurate cooling performance according to the operating state of the engine 11. Accordingly, overcooling at a low load can be suppressed, and useless energy consumption can be prevented.

4 Body 7 Front Wheel 8 Rear Wheel 11 Engine 33 Hoist Cylinder 36 Frame 39 Heat Exchanger Room 40 High Temperature Radiator 41 Low Temperature Radiator 42 First Auxiliary Radiator 43 Second Auxiliary Radiator 45 First Auxiliary Fan 46 Second Auxiliary Fan 47 First Auxiliary Motor 48 Second auxiliary motor 49 Cooling fan 50 Controller 54 Cooling water pipe 55 Temperature sensor (detection unit)
56 Temperature sensor (detection unit)
57 Rotation sensor (detection unit)
58 Torque sensor (detector)
60 fan clutch 100 dump truck (construction machine)
P1 Engine output lower limit threshold Pth Output threshold Q1 Heat generation amount lower limit threshold Qth Heat generation amount threshold Tth1 First temperature threshold Tth2 Second temperature threshold

Claims (5)

A radiator, a cooling fan that is driven by the engine and generates wind that cools the radiator, a cooling water pipe that supplies water cooled by the radiator to the engine, and the cooling fan and the output shaft of the engine are disconnected. In a cooling device for a construction machine having a fan clutch that comes into contact,
A downstream auxiliary radiator that is connected in series to the upstream radiator through the cooling water pipe and has a capacity set smaller than the radiator;
An auxiliary fan that is provided separately from the cooling fan and that generates air to cool the auxiliary radiator;
A detection unit for detecting an operating state of the engine;
Construction in response to said operating state of said detected engine detecting unit, characterized by comprising a controller for performing a control process for selectively actuating either one of the cooling fan and the auxiliary fan Machine cooling system. The construction machine cooling device according to claim 1,
The radiator comprises a high-temperature radiator disposed on the side close to the cooling fan, and a low-temperature radiator disposed on the side far from the cooling fan,
The auxiliary radiator comprises a first auxiliary radiator connected to the high temperature radiator via the cooling water pipe, and a second auxiliary radiator connected to the low temperature radiator via the cooling water pipe,
The auxiliary fan includes a first auxiliary fan that generates wind for cooling the first auxiliary radiator and a second auxiliary fan that generates wind for cooling the second auxiliary radiator. Cooling system. The construction machine cooling device according to claim 1,
The cooling device for a construction machine, wherein the detection unit includes a detection unit that detects an output of the engine. The construction machine cooling device according to claim 1,
The construction device cooling apparatus according to claim 1, wherein the detection unit includes a temperature sensor that detects a temperature of water flowing through the cooling water pipe. The construction machine cooling device according to claim 1,
The construction machine consists of a dump truck,
The construction machine cooling device according to claim 1, wherein the auxiliary radiator and the auxiliary fan are provided in a heat exchanger chamber disposed at a front side position of the dump truck in which the radiator and the cooling fan are accommodated.