JPH0726583A - Hot water circuit for construction machinery - Google Patents

Abstract

PURPOSE:To improve efficiency by circulating hot water between a wafer jacket and a hot water supply device for preheating and starting an engine and, then, causing hot water to flow from the water jacket to an operator's cabin heating device. CONSTITUTION:A hot water supply switch 15C is turned on to open a bypass open/close valve 18, and a manual three-way selector valve 22 is selected at a return pipe line 2 shown by an arrow A. Hot water heated with a hot water supply device 15, then, flows into the water jacket 8 of an engine 7 via a pipe line 12, and preheats the engine 7. Subsequently, after the engine 7 is started, the switch 15C is turned off to stop the operation of the device 15. Also, after the valve 18 is closed, the valve 22 is selected at a direction shown by an arrow B, and hot water is thereby caused to flow from the jacket 8 to a cabin heating device 14 to heat an operator's cabin 4. According to this construction, the engine 7 can be efficiently preheated, and a time until the starting state thereof can be shortened. Also, the thermal energy of the engine 7 can be effectively used, thereby effectively heating the cabin 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water circuit of a construction machine such as a hydraulic excavator, which is used for preheating an engine and heating an operator's cab when the construction machine is started.

[0002]

2. Description of the Related Art Generally, in extremely cold regions such as Alaska and Siberia, the winter temperature drops to about -50 ° C., so that it is difficult to start construction machines such as hydraulic excavators. For this reason,
In such a construction machine for cold regions, a hot water circuit for circulating hot water is provided in the engine and the driver's cab, and the hot water in the hot water circuit preheats the engine so that the engine can be started.

2 and 3, a hot water circuit of a hydraulic excavator will be described as an example of a hot water circuit of a construction machine of this type according to the prior art.

In the drawing, reference numeral 1 denotes a hydraulic excavator, which is composed of a lower traveling body 2 and an upper revolving body 3 provided on the lower traveling body 2 so as to be revolvable. Is a machine that is provided on the front side thereof and has a cabin 4 in which an indoor heating device 14 and the like, which will be described later, are installed, and a machine that is provided behind the cabin 4 and that houses an engine 7, a hot water supply device 15, and the like, which are described later. It is composed of a room 5 and a working device 6 which is located on the side of the operator's cab 4 and can be lifted and lowered.

Reference numeral 7 denotes an engine provided in the machine room 5. The engine 7 is provided with a water pump 7A and a cooling fan 7B driven by its rotation. In addition, a water jacket 8 through which warm water flows through a cylinder block (not shown) that constitutes the engine 7.
Is provided, and the water jacket 8 is provided with pipes 9 and 10.
The radiator 11 is connected via. Further, the water jacket 8 is connected to an indoor heating device 14, a hot water supply device 15 and the like, which will be described later, through conduits 12 and 13 similar to the conduits 9 and 10.

Reference numeral 14 denotes an indoor heating device such as a heater blower provided in the operator's cab 4. The indoor heating device 14 is connected to an outflow port of the water jacket 8 through a pipe line 13, and hot water from the water jacket 8 is supplied. To turn on and off the radiator 14A that circulates heat to warm the inside of the cab 4, and the warm air fan 14B that supplies warm air into the cab 4 by blowing air to the radiator 14A and the warm air fan 14B. Heating switch 14C.

Reference numeral 15 denotes a hot water supply device provided in the machine room 5 and used for supplying hot water into the water jacket 8. The hot water supply device 15 includes a pump 15A, a heat exchanger 15B and a hot water supply device. Switch 15C
The inflow side of the hot water supply device 15 is connected to the outflow side of the radiator 14A of the indoor heating device 14 via the pipe line 16, and the outflow side of the hot water supply device 15 is connected to the water jacket via the pipe line 12. It is connected to eight inlets. When the hot water supply switch 15C is turned on, the hot water supply device 15 operates the pump 15A and operates a heater (not shown) that burns fuel to heat the hot water flowing out from the radiator 14A. The hot water is heated through the exchanger 15B to obtain high-temperature hot water, and then the pipe 1 is supplied by the pump 15A.
2 is discharged into the water jacket 8 and then flowed into the water jacket 8.

When the circulation on-off valve 19 to be described later is opened while the engine 7 is operating, hot water is not only applied between the water jacket 8 and the radiator 11, but also between the room heating device 14 and the water jacket 8. It is designed to circulate.

Reference numeral 17 is a bypass pipe line provided by connecting the pipe lines 12 and 16 so as to bypass the hot water supply device 15, and 18 is a manual type pipe provided in the middle of the bypass pipe line 17. A bypass opening / closing valve consisting of a two-way opening / closing valve is shown. The bypass opening / closing valve 18 is opened by a driver's manual operation when the hot water supply device 15 is not used, and the hot water flowing out from the indoor heating device 14 is piped. The hot water supply device 15 having a high line resistance bypasses the hot water supply device 15 and directly flows into the pipe line 12. On the other hand, when the engine 7 is preheated by using the hot water supply device 15 such as when the engine 7 is started in a severe cold, the bypass opening / closing valve 18 is closed by the driver's manual operation, so that the hot water from the pipe 16 is removed. The hot water is supplied into the hot water supply device 15, and the hot water heated by the hot water supply device 15 is discharged toward the engine 7.

Reference numeral 19 denotes a circulation on-off valve which is located between the water jacket 8 and the room heating device 14 and which is provided in the middle of the pipeline 13 and which is a manual two-way opening / closing valve. 19 is opened by the driver's manual operation in winter,
The hot water from the hot water supply device 15 is circulated to the engine 7 and the indoor heating device 14 to preheat the engine 7 to a startable state, and at the same time, the hot water is introduced from the water jacket 8 into the indoor heating device 14 to heat the indoor heating device 14. Radiator 1
4A is heated.

On the other hand, the circulation on-off valve 19 is closed by a driver's manual operation in summer or the like, and hot water is circulated only between the water jacket 8 and the radiator 11 via the pipes 9 and 10, and the radiator 11 is closed. By cooling the hot water inside by the cooling fan 7B, the temperature of the hot water is maintained within an appropriate range.

The hot water circuit of the hydraulic excavator 1 according to the prior art has the above-described structure. For example, in order to start the engine 7 in a severe cold, the driver gets into the cab 4 and heats the switch 14C and supplies hot water. The switch 15C is turned on, the bypass opening / closing valve 18 is closed, the circulation opening / closing valve 19 is opened, and then the operator's cab 4 is exited to enter the building or the like in the construction site and stand by.

At this time, the hot water supply device 15 burns the fuel to heat the heater and drives the pump 15A by the current from the battery to generate the hot water from the heat exchanger 15B. It is supplied to the inside of the water jacket 8 to preheat the engine 7. And
After warming the engine 7, the hot water flows into the radiator 14A of the indoor heating device 14 via the pipe 13, and the radiator 14A
While circulating A, heat is dissipated to warm the cab 4 and
And is returned to the hot water supply device 15 via. In this way, by circulating hot water from the hot water supply device 15 through the water jacket 8 of the engine 7, the indoor heating device 14, etc., the engine 7 is preheated to be in a startable state and the interior of the cab 4 is warmed. To be

Then, based on the elapsed time and the like, the engine 7
When it is determined that the engine is ready to be started, the driver gets into the cab 4 from the building to start the engine 7, and when the engine 7 is started, thereafter, the bypass opening / closing valve 18 is opened. With hot water supply switch 15
The C is turned off to stop the hot water supply device 15. As a result, the hot water flowing out of the indoor heating device 14 flows into the bypass pipe line 17 and the hot water supply device 15 having a high pipe line resistance.
By being bypassed and flowing through the water jacket 8, it is heated by the heat of the engine 7.

On the other hand, when the temperature is high in summer or the like, the driver closes the circulation on-off valve 19, and the water jacket 8
If the hot water in the interior is prevented from flowing into the indoor heating device 14, the hot water is supplied to the water jacket 8 via the pipes 9 and 10.
Between the radiator and the radiator 11, and at this time the radiator 11
The temperature of the hot water is kept below a predetermined value by being cooled by the cooling fan 7B via the, so as to prevent the cylinder block from overheating.

[0016]

By the way, in the hot water circuit for the construction machine according to the above-mentioned prior art, the hot water supply device 1 is used.
The hot water generated in 5 is circulated through the pipe lines 12, 13, 16 and the water jacket 8 to preheat the engine 7 and warm the inside of the cab 4.

However, according to the conventional technique, since the engine 7 is preheated and the cab 4 is heated at the same time, the water temperature is unlikely to rise, and particularly in severe cold regions such as Siberia, the engine 7
The waiting time of the driver is 40 ~ 6
There is a problem that it takes a long time of about 0 minutes. Further, when the amount of heat radiated by the indoor heating device 14 is large, there is a problem that the hot water cannot reach a temperature sufficient to preheat the engine 7, which makes it extremely difficult to start the engine 7.

Furthermore, about 6 parts of antifreeze liquid is added to the water in the hot water circuit.
Freezing is prevented by adding 0%. However, in severe cold, this water becomes a sherbet and the viscosity increases significantly, so in order to preheat the engine 7 and warm the inside of the cab 4 at the same time, each pipe line 13 , 16 and the room heating device 14 become conduit resistance, the flow resistance becomes extremely large, and in some cases, the circulating amount of hot water flowing through the hot water supply device 15 is reduced to an empty state, and the hot water supply device 15 is damaged. I have something to do.

Therefore, not only the starting of the engine 7 is significantly delayed to reduce the work efficiency, but also the battery for supplying the current to the hot water supply device 15 is rapidly exhausted or the hot water supply device 15 is damaged. Etc., there is a problem of low reliability.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention can effectively preheat the engine before starting even in a severe cold, and the preheating time until the engine can be started. It is an object of the present invention to provide a hot water circuit for a construction machine capable of significantly shortening the reliability and improving the reliability.

[0021]

In order to solve the above-mentioned problems, the feature of the structure adopted by the present invention is that the engine is preheated between the water jacket of the engine and the hot water supply device and the room heating device. A manual switching valve is sometimes provided to circulate hot water between the water jacket and the hot water supply device and to allow the hot water from the water jacket to flow into the indoor heating device when heating the operation room.

[0022]

With the above construction, when the engine is preheated, the manual switching valve is switched so that the hot water is circulated between the hot water supply device and the engine, and the hot water is circulated between the water jacket and the hot water supply device. Preheat.

Further, when the engine is started, the manual switching valve is switched so that the water jacket of the engine and the room heating device are communicated with each other, and the hot water flowing out of the water jacket is flowed into the room heating device to heat the operation room. To do.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the embodiment, the same components as those in the prior art shown in FIGS. 2 and 3 described above are designated by the same reference numerals, and the description thereof will be omitted. The circulation on-off valve 19 provided in the middle of is closed.

In the figure, reference numeral 21 denotes a return conduit provided between the conduit 13 and the bypass conduit 17. One end of the return conduit 21 is connected to a manual three-way switch valve 22 described later. The other end side is located upstream of the bypass opening / closing valve 18 and is connected to the bypass conduit 17.

Reference numeral 22 is located between the water jacket 8 and the hot water supply device 15 and the room heating device 14, and is provided in the pipeline 1
3 is a manual three-way port switching valve as a manual switching valve provided to selectively switch between the return line 21 and the return line 21. The manual three-way port switching valve 22 is manually operated by a driver. By switching to the flow in the A direction, the pipe 13 on the water jacket 8 side of the engine 7 and the return pipe 21 are connected to each other, and the water jacket 8 is connected to the water jacket 8.
5 or the bypass opening / closing valve 18, while the arrow B
The water jacket 8 is connected to the indoor heating device 14 by communicating with the pipe line 13 by switching to the directional flow.

The hot water circuit of the construction machine according to the present embodiment has the above-mentioned structure, and its operation will be described below.

First, before starting the engine 7 in a severe cold, the driver gets into the cab 4 to turn on the hot water supply switch 15C, closes the bypass opening / closing valve 18, and closes the manual three-way port. The engine 7 is preheated by switching the switching valve 22 to the return pipe 21 side indicated by the arrow A.

That is, by switching the manual three-way switch valve 22 to the return pipe 21 side, the pipe 13 is returned to the return pipe 2
1. Since it is made to communicate with the inflow side of the hot water supply device 15 via the bypass pipe line 17, the hot water heated by the hot water supply device 15 is pumped by the pump 15 of the hot water supply device 15.
A is discharged to the pipe line 12 by A, flows into the water jacket 8 of the engine 7 from the pipe line 12, preheats the engine 7 while flowing through the water jacket 8, and the pipe line 16 via the return pipe line 21. It will flow into the inside and circulate between the water jacket 8 and the hot water supply device 15.

When it is determined that the engine 7 has been preheated and is ready to be started, the driver gets into the cab 4 from the building and starts the engine 7.

Next, when the engine 7 is started, the operator turns off the hot water supply switch 15C to stop the operation of the hot water supply device 15, opens the bypass opening / closing valve 18, and opens the manual three-way port. The switching valve 22 is switched in the direction of arrow B. As a result, the hot water flowing out of the water jacket 8 is transferred from the conduit 13 to the radiator 14 of the indoor heating device 14.
By inflowing into A, after starting the engine 7, the warm water flowing out from the water jacket 8 warms the cab 4.

In addition, when the temperature is high and it is not necessary to preheat the engine 7 before starting, such as in summer, or when it is not necessary to heat the inside of the operator's cab 4, the bypass opening / closing valve 18 is opened and manually operated. The return pipe 2 shown by the arrow A for the type three-way switch valve 22
Switch to 1 side. As a result, a part of the hot water in the radiator 11 is partially discharged from the pipe line 13, the return pipe line 21, the bypass passage 17,
While the remaining hot water circulates through the pipe 12,
It flows between the water jacket 8 and the radiator 11 via 10, and is cooled by the radiator 11 and the cooling fan 7B to be maintained at an appropriate temperature.

Thus, when preheating the engine 7, it is sufficient to switch the manual three-way port switching valve 22 in the direction of arrow A and circulate the hot water only between the water jacket 8 and the hot water supply device 15. The length of the circulating pipe can be shortened, and the flow resistance of the engine cooling water in the pipe can be reduced. Therefore, the hot water between the water jacket 8 and the hot water supply device 15 can be heated in a short time, and the engine 7 can be effectively preheated. Further, since the driving time of the pump 15A can be shortened, it is possible to prevent the battery from being consumed.

On the other hand, by switching the manual three-way switch valve 22 in the direction of arrow A, hot water will not flow to the room heating device 14 when the engine 7 is preheated. Pipe line 1 with large flow resistance
It is possible to circulate the hot water while avoiding the heating devices 3, 16 and the indoor heating device 14 to secure the circulation amount of the hot water to the hot water supply device 15, and thus to prevent the hot water supply device 15 from being damaged due to the empty heating state.

Further, since the condition of the engine 7 in severe cold depends on the judgment of the driver, it is determined by the driver whether or not the engine 7 is preheated to a predetermined temperature, and the manual three-way switch valve is used. It suffices to manually switch 22 to reliably start the engine 7.

After the engine 7 is started, the driver may switch the manual three-way switch valve 22 in the direction of arrow B to switch the hot water from the water jacket 8 to the room heating device 14 side. Therefore, the heat energy of the engine 7 generated during the work can be effectively used to effectively heat the inside of the cab 4.

Thus, according to the present embodiment, the engine 7 can be efficiently preheated, so that the preheating time until the engine 7 is ready to start can be greatly shortened, and the engine 7 can be quickly started for actual work. The operation efficiency of the hydraulic excavator 1 can be significantly improved. Further, since the preheating time of the engine 7 can be shortened, it is possible to prevent the battery from being consumed, prevent the hot water supply device 15 from being damaged, and significantly improve the reliability.

Although the hydraulic excavator 1 has been described as an example of the construction machine in the above embodiment, the present invention is not limited to this, and other construction machines for cold regions such as a hydraulic crane, a wheel loader, a truck, and a bulldozer. It can also be used widely.

Further, in the above-mentioned embodiment, the manual three-way switching valve is illustrated as the manual switching valve according to the present invention. However, this manual three-way switching valve is a switching valve having various types such as a ball valve and a spool valve. Is applicable, and the manual switching valve according to the present invention is not limited to the three-way switching valve,
A switching valve combined with a fuel control valve or a part of a multiple valve may be used.

[0040]

As described in detail above, according to the present invention, between the water jacket of the engine and the hot water supply device and the indoor heating device, and between the water jacket and the hot water supply device when preheating the engine. Since a manual switching valve that circulates hot water and heats the operating room to flow hot water from the water jacket into the indoor heating device is provided, when the engine is preheated, the manual switching valve is switched to switch between the water jacket and the hot water supply device. It suffices to circulate the hot water only during the period, and it is possible to efficiently preheat the engine and shorten the time until the engine is ready to start.

Further, since the length of the pipe line through which the hot water is circulated at the time of preheating the engine can be shortened and the flow resistance of the cooling water becomes small, the circulation amount of the hot water can be secured, and the hot water supply device in the empty water supply state Damage can be prevented.

Furthermore, since the engine can be quickly started to start the work, the work efficiency and reliability of the construction machine can be improved, and after the engine is started, the manual switching valve is set to the room heating device side. It is possible to effectively use the heat energy of the engine generated during switching and work to effectively heat the cab.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a hot water circuit of a hydraulic excavator according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a conventional hydraulic excavator.

FIG. 3 is an overall configuration diagram showing a hot water circuit used in a hydraulic excavator.

[Explanation of symbols]

 1 Hydraulic excavator (construction machinery) 7 Engine 8 Water jacket 14 Indoor heating device 15 Hot water supply device 22 Manual three-way switch valve (manual switch valve)

Claims (1)

[Claims] 1. An engine mounted on a construction machine, the engine having a water jacket through which hot water flows, an indoor heating device for circulating hot water flowing out from the water jacket of the engine to heat an operation room, and the indoor heating device. In a hot water circuit of a construction machine, which comprises a hot water supply device which is provided to be connected to a water jacket of an engine and is used when supplying hot water to the water jacket, a water jacket of the engine, a hot water supply device and an indoor heating device. In the meantime, when the engine is preheated, hot water is circulated between the water jacket and the hot water supply device, and when heating the operating room, the hot water from the water jacket is switched so as to flow into the indoor heating device. A hot water circuit for construction machinery, which is equipped with a valve.