JP2013035402A - Heating device for working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device for a working machine capable of preventing the deterioration of the capacity of transmitting the heat of an exhaust gas of an engine to engine cooling water caused by the effect of outside air in heating the engine cooling water using the heat of the exhaust gas of the engine in an extremely cold place.SOLUTION: The heating device for the working machine includes a blowout port 41, a blower 42, a heater core 44 heating air flowing from the blower 42 toward the blowout port 41, a heating pipe 45 introducing the engine cooling water from an engine cooling device 20 to the heater core 44, and a heating means 50 heating the engine cooling water flowing through the heating pipe 45 by the heat of the exhaust gas of the engine 10. The heating means 50 includes a heat receiving pipe 51 positioned in an exhaust pipe 11 extended from an exhaust manifold of the engine 10 toward the outside of the working machine (in a case 12a of a muffler 12) and forming a part of the heating pipe 45, and the heat receiving pipe 51 transmits the heat of the exhaust gas in the exhaust pipe 11 to the engine cooling water.

Description

  The present invention is a heating device provided in a work machine such as a dump truck or a hydraulic excavator, and heats engine cooling water with heat of exhaust gas of an engine mounted on the work machine, and heats the heated cooling water. It is related with the heating apparatus of the working machine used as a heat source.

  The automotive heating device disclosed in Patent Document 1 includes a first heat exchanger that absorbs the heat of engine exhaust gas, a thermosyphon that contains a fluid to which heat is transmitted from the first heat exchanger, A second heat exchanger that generates hot water by transferring the heat of the fluid in the thermosyphon to the engine cooling water, and a pipe that guides the hot water generated by the second heat exchanger to the heater core. The heater unit is located downstream of the fan, and transfers the heat of the hot water to the air sent from the fan. The air to which heat is transmitted from the heater core is guided into the vehicle interior, and as a result, the vehicle interior is heated.

JP-A-56-82619

  By the way, work machines such as dump trucks and hydraulic excavators are sometimes used in extremely cold regions. In this case, the work machine needs to be able to start heating the cab immediately after the operator gets on the work machine, that is, immediately after the engine is started.

  As described above, the automotive heating device disclosed in Patent Document 1 uses the heat of engine exhaust gas for heating. Since the exhaust gas of the engine is obtained immediately after the engine is started, this automotive heating device seems to be suitable for work machines used in extremely cold regions. It is conceivable that the devices that transmit the heat of the exhaust gas to the engine cooling water in the apparatus, that is, the first heat exchanger, the second heat exchanger, and the thermosiphon are cooled by the outside air in the extremely cold region. Immediately after startup, there is a possibility that heat sufficient for heating cannot be transferred to the engine coolant.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to heat the engine exhaust gas from the engine cooling water when the engine cooling water is heated using the heat of the engine exhaust gas in a severely cold region. An object of the present invention is to provide a heating device for a work machine that can prevent the ability to transmit to the machine from being lowered due to the influence of outside air.

  In order to achieve the above-mentioned object, a heating device for a work machine according to the present invention is configured as follows.

[1] A heating device for a work machine according to the present invention heats air that flows from an air outlet, a blower that causes a flow of air blown from the blower outlet, and the air flowing from the blower toward the blower outlet. A heater core; a heating pipe for guiding engine cooling water from the engine cooling device to the heater core; and heating means for heating the engine cooling water flowing through the heating pipe with heat of engine exhaust gas. In the heating apparatus for a working machine that heats air using engine cooling water heated by the means as a heat source, the heating means is located in an exhaust pipe that extends from an exhaust manifold of the engine toward the outside of the working machine. A heat receiving pipe forming a part of the pipe is provided, and the heat receiving pipe transfers heat of exhaust gas in the exhaust pipe to engine cooling water.

  In the heating apparatus for a work machine described in “[1]”, the heating means includes a heat receiving pipe that is located in an exhaust pipe extending from the exhaust manifold of the engine and forms a part of the pipe, and the exhaust gas is exhausted in the heat receiving pipe. The heat is transferred to the engine coolant. In other words, in the prior art, the heat of the exhaust gas is indirectly transmitted to the engine coolant using devices for transmitting heat (the first heat exchanger, the second heat exchanger, and the thermosiphon). However, in the heating device for a work machine according to the present invention, the heat of the exhaust gas can be directly transmitted to the engine cooling water by the heat receiving pipe being positioned in the exhaust pipe. Thus, when the engine cooling water is heated using the heat of the engine exhaust gas in a severe cold region, it is possible to prevent the ability to transmit the heat of the engine exhaust gas to the engine cooling water from being deteriorated due to the influence of outside air.

[2] A heating device for a work machine according to the present invention is the heating device for a work machine according to “[1]”, wherein the pipe portion located outside the exhaust pipe and the heat receiving pipe are received by the heat receiving pipe. A plurality of connecting pipes connected at a plurality of locations in the direction in which the heat pipe extends; a valve provided individually for each of the plurality of connecting pipes; a valve for opening and closing the connecting pipe; and a control means for the plurality of valves. The control means is characterized in that the distance until the engine cooling water enters and exits the exhaust pipe is changed by selectively opening one of the plurality of valves.

  In the heating device for a work machine described in “[2]”, the control means selectively opens one of the plurality of valves to thereby reduce the distance from when the engine coolant enters the exhaust pipe to when it exits. change. Thereby, the time during which the heat of the exhaust gas is transmitted to the engine coolant in the exhaust pipe, that is, the amount of heat transmitted to the engine coolant can be changed.

[3] A heating device for a work machine according to the present invention is the heating device for a work machine according to “[2]”, wherein the control unit includes a determination unit that determines an amount of heat required for the heating. The plurality of valves are controlled such that the distance is longer as the amount of heat determined by (1) is larger, and the distance is shorter as the amount of heat is smaller. Thus, the amount of heat transmitted to the engine coolant in the exhaust pipe can be changed according to the amount of heat required for heating.

[4] A heating device for a work machine according to the present invention is the heating device for a work machine according to any one of “[1]” to “[3]”, wherein the heat receiving pipe is a part of the exhaust pipe. It is located in the case of the silencer which comprises. As a result, the provision of the heat receiving tube is unlikely to be an obstacle due to the layout relationship with the equipment that is positioned around the heat receiving tube.

  As described above, the heating device for a work machine according to the present invention has the ability to transmit the heat of the engine exhaust gas to the engine coolant when the engine coolant is heated using the heat of the engine exhaust gas in a severe cold region. Can be prevented from lowering due to the influence of outside air. As a result, heating of the cab can be started immediately after the operator gets on the work machine, that is, immediately after the engine is started.

It is a side view of the hydraulic excavator which is an example of the working machine with which the heating apparatus which concerns on one Embodiment of this invention is provided. It is a figure which shows the outline of the heating apparatus which concerns on one Embodiment of this invention. It is a figure which shows the state of a thermostat in case engine cooling water circulates only in the inside of an engine. It is a figure which shows the state of a thermostat in case engine cooling water circulates between an engine and a radiator. It is a block diagram which shows the structure of the control system of the heating apparatus shown in FIG. It is a flowchart which shows the flow of the process performed by the structure of the control system shown in FIG.

  A heating apparatus for a work machine according to an embodiment of the present invention will be described with reference to FIGS.

  A hydraulic excavator 1 shown in FIG. 1 has a traveling body 2 that travels by driving a crawler belt 2 a, and a revolving body that is pivotably coupled to the upper portion of the traveling body 2, and that has a cab 4, a machine room 5, and a counterweight 6. 3 and a front working device 7 provided at the front portion of the swivel body 3 and having a boom 7a, an arm 7b, and a bucket 7c.

  An engine 10 (diesel engine) is stored in the machine room 5. The engine 10 is provided with an exhaust manifold (not shown) through which exhaust gas is discharged. An exhaust pipe 11 extending toward the outside of the hydraulic excavator 1 is connected to the exhaust manifold. The exhaust pipe 11 includes a silencer 12 that reduces exhaust noise, and an exhaust cylinder 13 (see FIG. 1) that extends upward from the silencer 12 and penetrates the ceiling of the machine room 5.

  In the machine room 5, a water-cooled engine cooling device 20 is attached to the engine 10. The engine cooling device 20 includes a cooling circuit 21 that circulates engine cooling water between the radiator 22 and the inside of the engine 10, and a cooling fan 23 that generates a flow of air that passes through the radiator 22.

  The cooling circuit 21 includes a cooling water pump 24 that causes a flow in the engine cooling water, an internal pipe 25 that guides the engine cooling water discharged from the cooling water pump 24 to the inside of the engine 10, and the internal pipe 25. A discharge pipe 26 connected to the radiator 22 and an introduction pipe 27 for guiding the engine cooling water that has passed through the radiator 22 to the cooling water pump 24 are provided. That is, the circulation of the engine cooling water in the cooling circuit is discharged from the cooling water pump 24, absorbs the heat of the engine 10 while flowing through the internal pipe 25, and is then led to the radiator 22 through the discharge pipe 26. Then, the heat is dissipated and then guided to the cooling water pump 24 through the introduction pipe 27 and discharged from the cooling water pump 24 again. The engine 10 is cooled by repeating the circulation of the engine cooling water.

  The cooling circuit 21 is provided with a thermostat 28. The thermostat 28 is provided between the internal conduit 25 and the discharge conduit 26. In this thermostat 28, the flow destination of the engine cooling water from the bypass conduit 29 connected to the introduction conduit 27 and the internal conduit 25 is selectively selected as one of the discharge conduit 26 and the bypass conduit 29. And a valve body 30 to be switched to. The valve body 30 has a predetermined engine cooling water temperature (for example, 80 ° C.), that is, a temperature lower than a temperature set as a lower limit value of the engine cooling water temperature that does not prevent each part of the engine 10 from reaching an appropriate temperature. When the temperature of the cooling water is low, the bypass line 29 is opened with the discharge line 26 closed as shown in FIG. 3, and when the temperature of the engine cooling water is equal to or higher than the specified temperature, as shown in FIG. In this state, the bypass line 29 is closed with the discharge line 26 opened. In other words, the thermostat 28 circulates only in the engine 10 without cooling the engine coolant with the radiator 22 in a state where each part of the engine 10 does not reach the proper temperature.

  As shown in FIG. 2, the heating device 40 according to the present embodiment includes an air outlet 41, a blower 42 that causes a flow of air blown from the outlet 41, and a blower motor that drives the blower 42. 43 (electric motor) and a heater core 44 that heats the air flowing from the blower 42 toward the outlet 41. The blower outlet 41, the blower 42, the blower motor 43, and the heater core 44 are provided in the cab 4.

  The heating device 40 is a pipe provided by branching from the internal pipe 25 on the upstream side of the thermostat 28 of the cooling circuit 21, and a heating pipe 45 that guides engine cooling water from the engine cooling apparatus 20 to the heater core 44. And heating means 50 for heating the engine coolant flowing in the heating pipe 45.

  The heating means 50 includes a heat receiving pipe 51 that is located in the case 12a of the silencer 12 that forms part of the exhaust pipe 11, and that forms part of the heating pipe 45. The heat receiving pipe 51 transfers the heat of the exhaust gas to the engine. It is transmitted to the cooling water. The engine cooling water (hot water) heated in the heat receiving pipe 51 is guided to the heater core 44 and serves as a heat source for heating the air in the heater core 44.

  The heating unit 50 further includes an adjustment unit 60 that enables adjustment of the amount of heat transmitted to the engine coolant in the heat receiving pipe 51. The adjusting means 60 is provided with a portion of the heating pipe 45 and the heat receiving pipe 51 located outside the silencer 12 (outside the exhaust pipe 11) at a plurality of places, for example, four places in the direction in which the heat receiving pipe 51 extends. The first to fourth connection pipes 61 to 64 to be connected and the first to fourth valves that are individually provided for the first to fourth connection pipes 61 to 64, respectively, and open and close the connection pipes. 71-74. Of the first to fourth valves 71 to 74, only the first valve 71 is open, similarly only the second valve 72 is open, similarly only the third valve 73 is open, and similarly only the fourth valve 74 is open. The distance from when the engine coolant enters the case 12a of the silencer 12 until it exits increases in the order of the opened state.

  As shown in FIG. 5, the heating device 40 further includes a hot water inlet temperature sensor 101 that converts a warm water inlet temperature, which is the temperature of engine cooling water at the inlet 44 a of the heater core 44, into a detection signal (electric signal) and outputs the detected signal (electric signal). The outside air temperature sensor 102 that converts the outside air temperature that is the temperature outside the chamber 4 into a detection signal (electric signal) and outputs the detection signal, and the air outlet temperature that is the air temperature at the air outlet 41 is converted into a detection signal (electric signal). Outlet temperature sensor 103 to be output, room temperature setting device 104 to output a command signal (electric signal) based on the input operation of the set value of the room temperature, and command signal (electric signal) based on the input operation of the set value of the blown air volume ), A hot water inlet temperature detection signal, an outside air temperature detection signal, an outlet temperature detection signal, a room temperature set value command signal, and an outlet air volume setting. Enter the command signal value, and a control device 100 which is the first to fourth control means for controlling the valve 71 to 74 based on these signals.

  The control device 100 is a microcomputer that performs processing using a CPU, a ROM, and a RAM, and includes a determination unit 100a that is a unit set by a control program. The determination means 100a receives the detection signal for the hot water inlet temperature, the detection signal for the outside air temperature, the detection signal for the outlet temperature, the command signal for the set value of the room temperature, and the command signal for the set value of the blowout air amount to the control device 100. The amount of heat required for heating is determined based on the hot water inlet temperature, the difference between the setting value of the outside air temperature and the room temperature, the difference between the setting value of the outlet temperature and the room temperature, and the setting value of the blowing air volume. is there.

  Then, the control device 100 selectively opens one of the first to fourth valves 71 to 74 based on the amount of heat determined by the determination means 100a, so that the engine cooling water is supplied to the case 12a of the silencer 12. The distance from the inside to the exit is changed. However, in order to prevent the temperature in the cab 4 from excessively rising, all the first to fourth valves 71 to 74 are closed when the hot water inlet temperature is 100 ° C. or higher.

  Note that the control device 100 also controls the blower motor 43 based on a command signal for the set value of the blown air volume.

  A control flow of the first to fourth valves 71 to 74 performed by the control device 100 will be described with reference to FIG.

  As shown in FIG. 6, the control device 100 inputs a room temperature setting value command signal from the room temperature setting device 104, stores the room temperature setting value, and sets the blown air volume setting value from the air volume setting device 105. Is input, and the set value of the blown air volume is stored (step S1).

  Next, the control device 100 inputs the detection signal of the hot water inlet temperature from the hot water inlet temperature sensor 101, the detection signal of the outside air temperature from the outside air temperature sensor 102, and the detection signal of the outlet temperature from the outlet temperature sensor 103. (Step S2).

  Next, the control device 100 requests the heating by the determination means 100a based on the hot water inlet temperature, the difference between the setting value of the outside air temperature and the room temperature, the difference between the setting value of the outlet temperature and the room temperature, and the setting value of the blowing air volume. The amount of heat to be determined is determined (step S3).

  Next, the control device 100 selects and opens one of the first to fourth valves 71 to 74 based on the amount of heat determined by the determination means 100a (step S4), and returns to the routine from step S2. Thereafter, the routine of “Step S2 → Step S3 → Step S4” is repeated. Thereby, the state of the 1st-4th valves 71-74 will be in the state where only the 4th valve 74 was opened, for example immediately after the start of heating, and then the amount of heat required for heating by the rise in room temperature is one step. In conjunction with each lowering, the state is shifted to a state where only the third valve 73 is opened, a state where only the second valve 72 is opened, and a state where only the first valve 71 is opened.

  According to the heating device 40 of the working machine according to the present embodiment, the following effects can be obtained.

  In the heating device 40 according to the present embodiment, the heating means 50 transmits the heat of the exhaust gas to the engine coolant through the heat receiving pipe 51 located in the exhaust pipe 11 of the engine 10 (in the case 12a of the silencer 12). . In other words, in the prior art, the heat of the exhaust gas is indirectly transmitted to the engine coolant using devices for transmitting heat (the first heat exchanger, the second heat exchanger, and the thermosiphon). However, in the heating device 40 according to the present embodiment, the heat receiving pipe 51 is located in the exhaust pipe 11 so that the heat of the exhaust gas can be directly transmitted to the engine cooling water. As a result, when the engine cooling water is heated using the heat of the exhaust gas of the engine 10 in a severe cold region, the ability to transmit the heat of the exhaust gas of the engine 10 to the engine cooling water can be prevented from being lowered due to the influence of the outside air. .

  In the heating device 40 according to the present embodiment, the control device 100 selectively opens one of the first to fourth valves 71 to 74 so that the engine cooling water enters the exhaust pipe 11 (the case of the silencer 12). 12a) Change the distance from entering to exiting. Thereby, the time during which the heat of the exhaust gas is transmitted to the engine coolant in the exhaust pipe 11, that is, the amount of heat transmitted to the engine coolant can be changed.

  In the heating device 40 according to the present embodiment, the control device 100 determines that the distance from when the engine coolant enters the exhaust pipe 11 (in the case 12a of the silencer 12) until it exits is determined by the determination unit 100a. The first to fourth valves 71 to 74 are controlled so as to become longer as the value becomes larger and shorter as the amount of heat becomes smaller. Thereby, the amount of heat transmitted to the engine coolant in the exhaust pipe 11 can be changed according to the amount of heat required for heating.

  In the heating device 40 according to the present embodiment, the heat receiving pipe 51 is located in the case 12 a of the silencer 12 that forms part of the exhaust pipe 11. As a result, the provision of the heat receiving pipe 51 is unlikely to be an obstacle due to the layout relationship with the equipment that is positioned around the heat receiving pipe 51.

  The heating apparatus 40 according to the present embodiment is applied to the excavator 1. The engine 10 mounted on the hydraulic excavator 1 is often a larger engine than the engine mounted on an automobile. In this case, a larger amount of exhaust gas can be obtained than that of an automobile. Can get to.

  In addition, although the heating apparatus 40 which concerns on this embodiment was applied to the hydraulic excavator 1, the working machine used as the application object of this invention may be other kinds of working machines, such as a dump truck. .

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Running body 2a Crawler belt 3 Rotating body 4 Operator room 5 Machine room 6 Counterweight 7 Front work device 7a Boom 7b Arm 7c Bucket 10 Engine 11 Exhaust pipe 12 Silencer 12a Case 13 Exhaust cylinder 20 Engine cooling device 21 Cooling circuit 22 Radiator 23 Cooling fan 24 Cooling water pump 25 Internal conduit 26 Discharge conduit 27 Introduction conduit 28 Thermostat 29 Bypass conduit 30 Valve body 40 Heating device 41 Blower outlet 42 Blower 43 Blower motor 44 Heater core 44a Inlet 45 Heating piping 50 Heating means 51 Heat receiving pipe 60 Adjusting means 61-64 First to fourth connecting pipes 71-74 First to fourth valves 101 Hot water inlet temperature sensor 102 Outside air temperature sensor 103 Air outlet temperature sensor 104 Room temperature setting device 105 Air volume setting device 100 Control device 100a determination means

Claims (4)

An air outlet, a blower that causes a flow of air blown from the blower outlet, a heater core that heats air flowing from the blower toward the outlet, and engine cooling water from the engine cooling device to the heater core A heating pipe for guiding the air and heating means for heating the engine cooling water flowing through the heating pipe with the heat of the exhaust gas of the engine, and the heater core heats air using the engine cooling water heated by the heating means as a heat source. In the working machine heating device
The heating means includes a heat receiving pipe which is located in an exhaust pipe extending from the exhaust manifold of the engine toward the outside of the work machine and forms a part of the heating pipe, and the heat receiving pipe includes exhaust gas in the exhaust pipe. A heating device for a work machine, wherein heat is transferred to engine coolant. In the heating device of the work machine according to claim 1,
A plurality of connecting pipes connecting the portion of the heating pipe located outside the exhaust pipe and the heat receiving pipe at a plurality of locations in the extending direction of the heat receiving pipe;
A valve that is provided individually for each of the plurality of connecting pipes, and that opens and closes the connecting pipes;
These multiple valves are provided with control means,
The said control means changes the distance until engine cooling water enters into the said exhaust pipe and exits by selectively opening one of the said some valve | bulb, The heating apparatus of the working machine characterized by the above-mentioned. In the heating device of the work machine according to claim 2,
The control means includes determination means for determining the amount of heat required for heating, and the distance increases as the amount of heat determined by the determination means increases, and the distance decreases as the amount of heat decreases. A heating device for a work machine, characterized by controlling a valve. In the heating apparatus of the working machine of any one of Claims 1-3,
The heating apparatus for a working machine, wherein the heat receiving pipe is located in a silencer case forming a part of the exhaust pipe.

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