JP2004116489A - Construction equipment provided with air-cooled intercooler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the cooling capacity of an intercooler with a small-sized and compact structure without increasing the flow rate of cooling air, when effectively cooling supercharging air in a high temperature state to a predetermined level. <P>SOLUTION: A cooler 14 for the secondary cooling of the intercooler is arranged on the most upstream side of flow of the cooling air by a cooling fan 17. A cooler 23 for the primary cooling to be provided in an engine installation section 2, is arranged in a region where the cooler 23 does not interfere with an engine 10 or its peripheral device and where the flow rate is high. The cooler 23 for the primary cooling is provided at a position obliquely behind the cooling fan 17. The cooler 23 for the primary cooling and the cooler 14 for the secondary cooling are connected to each other via a communication pipe 29. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a construction machine such as a hydraulic shovel, for example, and particularly to a structure for supplying supercharged air to an engine, and includes an air-cooled intercooler for cooling the supercharged air. It relates to construction machinery.
[0002]
[Prior art]
As a construction machine, for example, a hydraulic shovel is provided with a diesel engine as a power source, and the hydraulic pump is driven by the engine so that various actuators are operated by discharge pressure from the hydraulic pump. For this purpose, a radiator and an oil cooler are provided for the purpose of cooling the engine and cooling the hydraulic oil circulating in the hydraulic circuit. Further, in order to improve the output of the engine and purify the exhaust gas, the air supplied to the cylinder of the engine is supercharged, and an intercooler is provided to cool the supercharged air. . The main heat exchangers of construction machinery are described above, and each of these heat exchangers is generally air-cooled. In addition, a cooling fan is used to form the flow of the cooling air, and the cooling fan is configured to be driven by using the engine as a power source.
[0003]
An engine is installed in an engine room constituting a building of an upper revolving structure of a construction machine, and a cooling fan for cooling the heat exchanger is connected to the engine. The cooling fan is of a suction type, and the side farther from the engine is the most upstream side of the cooling air, and an outside air intake is provided in the cover of the engine room, so that the outside air can be taken in from the outside air intake. A configuration in which the three heat exchangers described above are arranged in series in the front-rear direction of the flow path of the cooling air by the cooling fan has been conventionally known (for example, see Patent Document 1). Since the supercharged air flowing in the intercooler needs to be cooled to the lowest temperature, it is arranged on the most upstream side. The radiator and the oil cooler cool the fluid to be cooled to substantially the same temperature.However, since the radiator is attached to the engine, the radiator is located downstream and the oil cooler is located upstream from the viewpoint of pipe routing. It is common to arrange.
[0004]
The arrangement of each of these heat exchangers is not only the one described above, but also includes a separate intercooler that needs to be cooled to the lowest temperature. Then, the oil cooler and the radiator are cooled by a cooling fan directly connected to the engine, and a chamber that is thermally isolated from the engine, the oil cooler, the radiator, and the like is formed. A second cooling fan for supplying wind is provided, and the second cooling fan is driven by a hydraulic motor.
[0005]
In addition, there is also known one using two intercoolers (for example, see Patent Document 2). One intercooler is air-cooled, and the other is water-cooled. When the temperature of the supercharged air is high, the supercharged air is cooled by both the air-cooled intercooler and the water-cooled intercooler, and the supercharged air is supercooled by the air-cooled intercooler as in a cold district. In such a case, the water-cooled intercooler acts to increase the temperature of the supercharged air.
[0006]
[Patent Document 1]
JP-A-9-125972 (pages 2-4, FIGS. 1 and 5)
[Patent Document 2]
JP 2001-342838 A (page 4, FIG. 1)
[0007]
[Problems to be solved by the invention]
By the way, in order to prevent environmental pollution and the like, the demand for purifying exhaust gas in diesel engines tends to be more severe, and therefore, it is necessary to further increase the compression amount of supercharged air supplied to the engine. It has become to. When the supercharged air is highly compressed, a problem arises in that the temperature is increased by adiabatic compression. On the other hand, in the exhaust gas purification described above, the temperature of the supercharged air to the engine also affects the degree of exhaust gas purification. In other words, if the temperature of the supercharged air is too high, the density of the air will be low, so that the amount of air supplied to the cylinder will be small, and complete combustion in the cylinder will not be performed, and the exhaust gas will become dirty. Become.
[0008]
From the above, the cooling capacity of the intercooler must be improved. In an air-cooled intercooler, the cooling air is taken in from outside air, so that the temperature of the cooling air itself cannot be lowered. Therefore, the cooling capacity must be improved by increasing the amount of cooling air or increasing the heat dissipation area of the intercooler. However, when increasing the flow rate of the cooling air, the cooling fan must be rotated at a high speed, and the noise when driving the fan becomes remarkable. Therefore, there is a limit to speeding up the rotation of the cooling fan in terms of noise regulation and the like. In order to improve the cooling capacity of the intercooler without increasing the noise, it is conceivable to increase the heat radiation area. However, when the intercooler is provided so as to be arranged in the flow direction of the cooling air with a radiator or an oil cooler as another heat exchanger, problems such as lowering the heat balance of the radiator and the oil cooler occur.
[0009]
Here, if the cooling fan dedicated to the intercooler is used to independently cool only the intercooler, and if the heat dissipation area of the intercooler is widened and the outer diameter of the cooling fan blades is increased, the noise will be significantly increased. In addition, the cooling capacity of the intercooler can be increased without lowering the heat balance of the other heat exchangers. However, the demand for compact upper revolving units in construction equipment, such as small-rotating hydraulic excavators, tends to be higher, and an intercooler, a cooling fan, and a hydraulic motor, which is a driving means for the intercooler, are installed on the upper revolving unit. In many cases, it is not possible to secure the space to be used.
[0010]
On the other hand, if the cooling of the supercharged air supplied to the engine is performed by two systems of an air cooling system and a water cooling system, the configuration becomes complicated. In this prior art, a water-cooled intercooler is used to prevent overcooling, and when a high cooling capacity is required, it depends on an air-cooled intercooler. In other words, the water-cooled intercooler is not designed to perform a special function. Therefore, even when supercharging air is cooled by two systems, in order to actually lower the temperature of supercharged air at a high temperature significantly, an air-cooled intercooler must be used. A similar problem will occur.
[0011]
The present invention has been made in view of the above points, and an object of the present invention is to effectively cool a supercharged air in a high temperature state to a predetermined level, thereby achieving a small and compact size. With the configuration, it is possible to improve the cooling capacity of the intercooler without increasing the amount of cooling air.
[0012]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides an intercooler for cooling a supercharged air supplied to an engine to a heat exchanger installation part in an engine room having an engine installation part and a heat exchanger installation part. A heat exchanger is provided, and a cooling fan is provided for flowing cooling air from an outside air intake section formed on the heat exchanger installation section side to an exhaust section formed on the engine installation section through the heat exchanger. Construction machine, wherein the intercooler is composed of a primary cooling cooler and a secondary cooling cooler in order from the inlet side of the supercharged air, and these two coolers are connected by piping, and the primary cooling A cooler is arranged in the engine installation part to cool by an air flow on the downstream side of the cooling fan, and the secondary cooling cooler is provided in the heat exchanger installation part by an air flow by the cooling fan. It is characterized in that it has a structure in which disposed upstream.
[0013]
The intercooler in the present invention has a two-stage structure, in which primary cooling is performed on the engine installation side, and then secondary cooling is performed on the heat exchanger installation section. The supercharged air, which has become hot due to the high compression, is radiated to some extent by the primary cooling cooler arranged in the engine installation part, and is then arranged in the heat exchanger installation part to cool the supercharged air to the target temperature. The burden on the next cooling cooler can be reduced. Therefore, the cooler for primary cooling may be somewhat compact. The primary cooling cooler is a space existing inside the engine installation portion and at a position where the flow velocity of the air flow on the downstream side of the cooling fan is as fast as possible. More preferably, it is located between the cooling fan and the supercharger.
[0014]
There is no need to provide a special partition between the engine installation section and the heat exchanger installation section.However, if a circulation prevention wall is provided between them, the primary cooling cooler and the secondary cooling cooler are not provided. Are located in separate chambers defined by anti-circulation walls. Therefore, the piping from the primary cooling cooler to the secondary cooling cooler and the piping from the secondary cooling cooler to the engine are provided so as to penetrate the anti-circulation wall. Although the heat exchanger includes at least an intercooler, a hydraulically driven construction machine equipped with an engine requires a radiator and an oil cooler as the heat exchanger. Further, a condenser for an air conditioner or the like is provided as a heat exchanger other than these. In any case, the cooler for cooling the secondary side of the intercooler is arranged on the most upstream side of the cooling air.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIGS. 1 and 2 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes an engine room in a building of a construction machine. The interior of the engine room 1 is divided into an engine installation section 2, a heat exchanger installation section 3, and a hydraulic pump installation section 4. The engine 10 is installed in the engine installation section 2, and the hydraulic pump 11 connected to the engine 10 is installed in the hydraulic pump installation section 4. The engine installation part 2 and the hydraulic pump installation part 4 are separated by a partition wall 5.
[0016]
The heat exchanger installation section 3 is provided with a heat exchanger. The heat exchanger includes a radiator 12 and an oil cooler 13, and a two-stage secondary cooler 14 for an intercooler as described later. Furthermore, a condenser 15 of an air conditioner is installed as another heat exchanger as required. The battery 16 is installed by utilizing a lower space in the heat exchanger installation section 3.
[0017]
Among the covers constituting the engine room 1, an outside air intake portion 6 is formed in the side cover 1 a and the upper cover 1 b on the heat exchanger installation portion 3 side, and the upper cover 1 b is provided at the position of the engine installation portion 2. An exhaust portion 7 is formed in the lower cover 1c. The outside air intake section 6 and the exhaust section 7 are composed of a punch board, a louver, and the like.
[0018]
The outside air intake section 6 and the exhaust section 7 are for forming a flow of cooling air inside the engine room 1, and in order to flow the cooling air, a boundary between the engine installation section 2 and the heat exchanger installation section 3 is formed. The part is provided with a cooling fan 17. The cooling fan 17 is driven by the engine 10. For this purpose, a fan pulley 18 is provided on a rotating shaft 17 a of the cooling fan 17, and a crank pulley 19 is provided on the engine 10. A fan belt 20 is wound between the pulley 18 and the crank pulley 19. Therefore, when the engine 10 is driven, the cooling fan 17 is also driven to rotate at the same time. Further, a shroud 21 is provided so as to surround the cooling fan 17. Further, a circulation prevention wall 22 is provided between the radiator 12 and the cover of the engine room 1. Therefore, as indicated by the arrow in FIG. 1, outside air is taken into the heat exchanger installation section 3 from the outside air intake section 6, exchanges heat with each of the above-described heat exchangers, and is guided into the engine installation section 2. Further, an air flow of discharging to the outside through the exhaust unit 7 is effectively formed.
[0019]
As a heat exchanger, an intercooler for supplying supercharged air to the engine 10 has a two-stage configuration including the above-described secondary cooling cooler 14 and the primary cooling cooler indicated by reference numeral 23 in the drawing. . Although the air supplied to the cylinder of the engine 10 is taken in through the intake pipe 24, foreign matters and the like are removed in advance by an air cleaner (not shown). On the other hand, the exhaust gas from the cylinder of the engine 10 is discharged to the outside from the exhaust pipe 25 via the muffler 26. A supercharger 27 is connected to the exhaust pipe 25. The supercharger 27 has a turbine. By rotating the turbine at a high speed, the air supplied from the intake pipe 24 is compressed and supplied to the engine 10. Then, the flow rate of the exhaust gas passing through the exhaust pipe 25 is used to rotationally drive the turbine.
[0020]
In order to improve the output of the engine 10 and purify the exhaust gas, it is necessary not only to increase the pressure of the supercharged air supplied to the engine 10 through the supercharger 27 but also to increase the supercharged air. It is necessary to lower the temperature of the supply air. Here, when air is pressurized, the temperature instantaneously rises due to adiabatic compression. Specifically, the temperature is 200 ° C. or higher. On the other hand, the temperature of the supercharged air supplied to the engine 10 needs to be approximately 80 ° C. or lower. The intercooler cools the supercharged air, which has been heated by pressurizing the air with the supercharger 27, to a temperature appropriate for supplying to the engine 10.
[0021]
When there is no strict regulation on exhaust gas and supercharging is performed mainly for improving the output of the engine, the temperature is about 120 ° C at the outlet side of the turbocharger, and this temperature is reduced to 80 ° C or less by the intercooler. If so, a small intercooler provided in the heat exchanger installation section can sufficiently exert a cooling effect. However, if the supercharged air supplied to the intercooler has a temperature of 200 ° C. or higher, the necessary cooling cannot be performed only by the small intercooler provided in the heat exchanger installation section. On the other hand, if the size of the intercooler is increased, there is a possibility that the heat balance of the other heat exchangers such as the radiator and the oil cooler may be reduced. Also, when the amount of air blown by the cooling fan is increased, extremely unpleasant noise is generated.
[0022]
By the way, inside the engine installation part 2, the temperature of the air flowing from the cooling fan 17, which is the inlet part of the air flow, to the exhaust part 7 is approximately 100 ° C. or less. At a position near the cooling fan 17, an annular passage is formed between the end of the engine 10 and the inside of the shroud 21. It may be faster than the interior and its temperature may be lower. A primary cooling cooler 23 is arranged inside the engine installation section 2, and an inflow pipe 28 from a supercharger 27 is connected to the primary cooling cooler 23. As a result, the temperature of the supercharged air in a temperature state of 200 ° C. or more is increased to a maximum near 100 ° C. which is the temperature in the engine installation part 2, specifically, 120 ° C. or less at most. It can be cooled to the temperature of. Moreover, there is a space around the engine 10 in the engine installation section 2, and there is no difficulty in securing a space for installing the primary cooling cooler 23. Furthermore, in order to supply the cooling air to the primary cooling cooler 23, there is no need to provide a separate cooling air supply source, and the air flow downstream of the cooling fan 17 that has cooled the various heat exchangers is changed to the primary cooling cooler 23. 23 can be used as a cooling source.
[0023]
The supercharged air thus primarily cooled is sent to the secondary cooling cooler 14 by a communication pipe 29 extending through the circulation prevention wall 22. Here, the secondary cooling cooler 14 is disposed upstream of the radiator 12 and the oil cooler 13 in the flow of the cooling air from the cooling fan 17 in the heat exchanger installation section 3. No heat exchanger is provided upstream of the cooler 14. Therefore, the outside air taken in from the outside air intake section 6 first passes through the secondary cooling cooler 14 to cool the supercharged air as the fluid to be cooled. Here, although the supercharged air is at an extremely high temperature in order to be in a high compression state, the temperature is lowered by the primary cooling cooler 23, and specifically, is lowered to about 120 ° C. Therefore, it is not necessary to use a particularly large configuration in order to reduce this temperature to a temperature of 80 ° C. or lower. Therefore, there is no possibility that the heat balance of the oil cooler 13 and the radiator 12 located downstream of the secondary cooling cooler 14 is reduced.
[0024]
As described above, the supply pipe 30 is connected to the secondary cooling cooler 14 which is the rear side of the two-stage intercooler, and the other end of the supply pipe 30 is connected to the cylinder of the engine 10. I have. Thus, low-temperature supercharged air is supplied to the cylinder in a high compression state, so that the output of the engine 10 is improved and the exhaust gas is purified.
[0025]
Here, among the primary and secondary cooling coolers 23 and 14 constituting the intercooler, the secondary cooling cooler 14 is arranged at the most upstream side of the flow of the cooling air by the cooling fan 17. On the other hand, the primary cooling cooler 23 installed in the engine installation section 2 can be arranged in the engine installation section 2 without interfering with the engine 10 and its peripheral devices, and cools the primary cooling cooler 23. It must be installed in a place where the flow velocity necessary for the above exists, particularly in a region where the flow velocity is high. Furthermore, a position between the cooling fan 17 and the supercharger 27 is desirable from conditions such as simplification of pipe routing.
[0026]
1 and 2, the primary cooling cooler 23 is positioned obliquely rearward of the cooling fan 17 and below the portion where the exhaust portion 7 of the upper cover 1b is provided, and is substantially parallel to the lower cover 1b. Are located. Further, as is apparent from FIG. 2, the primary cooling cooler 23 is not at a position directly above the engine 10 but at a position deviated to one side. With such a configuration, not only can the cooling efficiency of the primary cooling cooler 23 be sufficiently high, but also the communication pipe 29 from the primary cooling cooler 23 to the secondary cooling cooler 14 can extend straight, Piping of piping becomes easy.
[0027]
Further, as shown in FIG. 3, the primary cooling cooler 23 can be arranged in a direction orthogonal to the upper cover 1b. In consideration of the positional relationship between the engine 10 and the cooling fan 17 and the size, etc., the cooling fan 17 is an axial fan in particular. The amount of ventilation can be increased.
[0028]
Further, considering that the exhaust flow path from the cooling fan 17 to the upper cover 1b is in the radial direction, as shown in FIG. 4, the exhaust flow path is not parallel to the upper cover 1b, but is slightly lower on the inflow pipe 28 side. You can also make it tilt. Further, as shown in FIG. 5 and FIG. 6, the inflow pipe 28 side may be inclined slightly away from the cooling fan 17 from the position of the primary cooling cooler 23 shown in FIG. The point is that, in the space where the primary cooling cooler 23 can be arranged in the engine installation section 2, a portion where the flow velocity on the downstream side of the cooling fan 17 is as fast as possible and the amount of air flow to the primary cooling cooler 23 is large can be obtained. Optimally placed.
[0029]
【The invention's effect】
As described above, in effectively cooling the supercharged air that is in a high temperature state to a predetermined level, the cooling capacity of the intercooler is increased without increasing the cooling air volume by a small and compact configuration. Various effects such as improvement can be achieved.
[Brief description of the drawings]
FIG. 1 is a sectional view of an engine room according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 is a sectional view similar to FIG. 1, showing a second embodiment of the present invention.
FIG. 4 is a sectional view similar to FIG. 1, showing a third embodiment of the present invention.
FIG. 5 is a sectional view similar to FIG. 1, showing a fourth embodiment of the present invention.
FIG. 6 is a sectional view taken along line BB of FIG. 5;
[Explanation of symbols]
REFERENCE SIGNS LIST 1 engine room 2 engine installation part 3 heat exchanger installation part 6 outside air intake part 7 exhaust part 10 engine 12 radiator 13 oil cooler 14 secondary cooling cooler 17 cooling fan 21 shroud 22 anti-circulation wall 23 primary cooling cooler 27 excessive Feeder 28 Inflow pipe 29 Communication pipe 30 Supply pipe

Claims (3)

A heat exchanger including an intercooler for cooling supercharged air supplied to the engine to the heat exchanger installation section is installed in an engine room including an engine installation section and a heat exchanger installation section, and the heat exchange In a construction machine provided with a cooling fan for flowing cooling air from an outside air intake section formed on a vessel installation section side to an exhaust section formed on the engine installation section through the heat exchanger,
The intercooler is composed of a primary cooling cooler and a secondary cooling cooler in order from the inflow side of the supercharged air, and these two coolers are connected by piping.
The cooler for primary cooling is disposed in the engine installation portion, and is cooled by an air flow on the downstream side of the cooling fan,
A construction machine comprising an air-cooled intercooler, wherein the secondary cooling cooler is arranged in the heat exchanger installation section on the upstream side of the airflow by the cooling fan. A circulation prevention wall is provided between the engine installation section and the heat exchanger installation section, and a pipe from the primary cooling cooler to the secondary cooling cooler and the secondary cooling in the intercooler are provided. The construction machine provided with an air-cooled intercooler according to claim 1, wherein a pipe from the air cooler to the engine is provided so as to penetrate the anti-circulation wall. The heat exchanger comprises the intercooler, a radiator and an oil cooler arranged in series, and the cooler for cooling the secondary side of the intercooler is located on the most upstream side of the cooling air formed by the cooling fan. The construction machine provided with the air-cooled intercooler according to claim 1, wherein the construction machine is arranged.

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