JP2005139952A - Construction machine with air-cooled intercooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the cooling capacity of an intercooler without changing the capacity of a cooling fan or the installation space of a heat exchanger when cooling supercharged air of an engine.
A plurality of intercoolers that cool supercharged air supplied to an engine in an engine room including an engine installation unit and a heat exchanger installation unit. A cooling fan in which various types of heat exchangers are installed, and the cooling air flows from the outside air intake part 6a formed on the heat exchanger installation part 6 side through the heat exchanger toward the exhaust part 5a formed in the engine installation part 5 17 is provided in the engine 10, and at least the intercooler is disposed independently at a position independent of other heat exchangers between the outside air intake section and the cooling fan.
[Selection] Figure 2

Description

  The present invention relates to a construction machine such as a hydraulic excavator, and is particularly configured to supply supercharged air to an engine, and includes an air-cooled intercooler for cooling the supercharged air. Concerning construction machinery.

  As a construction machine, for example, a hydraulic excavator includes a diesel engine as a power source, and a hydraulic pump is driven by the engine, and 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 the hydraulic fluid circulating in the hydraulic circuit. Further, in order to improve the engine output and clean the exhaust gas, the air supplied to the engine cylinder is supercharged, and an intercooler is provided to cool the supercharged air. . The main heat exchangers of construction machinery are as described above, and these heat exchangers are generally air-cooled. In addition, a cooling fan is used to form a flow of cooling air, and this cooling fan is configured to drive the engine as a power source.

  A cooling fan for cooling the above-described heat exchanger is provided in an engine room which is formed by a building cover of an upper swing body of a construction machine and in which the engine is installed so as to be connected to the engine. This cooling fan is configured by a suction type, and the side farther from the engine is the most upstream side of the cooling air, and an outside air intake portion is provided in the cover of the engine room, and outside air is taken in from this outside air intake portion. A configuration in which the above-described three heat exchangers are arranged in series in the front-rear direction of the flow path of the cooling air by the cooling fan is conventionally known as disclosed in Patent Document 1, for example. And since the supercharged air which flows through the inside of an intercooler needs to cool to the lowest temperature, it is arrange | positioned at the most upstream side. The radiator and oil cooler cool the fluid to be cooled to almost the same temperature. However, because the radiator is attached to the engine, the radiator is placed downstream of the cooling air from the viewpoint of piping routing. Is generally arranged upstream.

The arrangement of each of these heat exchangers is not limited to the one described above, but may include an intercooler that needs to be cooled to the lowest temperature. The oil cooler and radiator are cooled by a cooling fan directly connected to the engine to form a chamber that is thermally shut off from the engine, oil cooler, radiator, and the like. A second cooling fan for supplying wind is installed, and this second cooling fan is driven by a hydraulic motor.
JP-A-9-125972

  By the way, in order to prevent environmental pollution, etc., there is a tendency that the demand for exhaust gas purification in a diesel engine becomes more severe. For this reason, it is necessary to further increase the amount of compression of supercharged air supplied to the engine. It has become to. When supercharging air is highly compressed, a high temperature due to adiabatic compression becomes a problem. On the other hand, in the exhaust gas cleaning described above, the temperature of the supercharged air to the engine also affects the degree of exhaust gas cleaning. That is, if the temperature of the supercharged air is too high, the density of the air is lowered, so that the amount of air supplied into the cylinder is reduced and combustion in the cylinder is performed at a high temperature, so that the NOx concentration is increased.

  From the above, it is necessary to improve the cooling capacity of the intercooler. In the air-cooled intercooler, the cooling air is taken in from outside air, so the temperature of the cooling air itself cannot be lowered. Therefore, it is necessary to improve the cooling capacity by increasing the amount of cooling air or increasing the heat dissipation area of the intercooler. However, when the amount of cooling air is increased, the cooling fan must be rotated at a high speed, and noise during driving of the fan becomes significant. Therefore, there is a limit to speeding up the cooling fan from the point of noise regulation. 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 arranged in series with the other heat exchanger radiator or oil cooler in the flow direction of the cooling air, the cooling air flow passing through the intercooler is located on the downstream side of the radiator. The cooling efficiency is reduced by being blocked by the oil cooler and the cooling air passing through these radiators, oil coolers, etc. on the downstream side rises in temperature compared to the outside air as it passes through the intercooler and is heat-exchanged. Therefore, problems such as lowering the heat balance occur. Moreover, since the area of the core part of the intercooler is set smaller than the area of the heat exchanger such as a radiator or an oil cooler as in the above-described conventional example, the core is installed by installing the intercooler on the most upstream side. Despite the fact that it is designed to pass through low-temperature outside air as the cooling air that passes through, the oil cooler and the radiator on the downstream side increase the airflow resistance, including its own airflow resistance, so bypass from around the intercooler. Therefore, the cooling air does not always flow efficiently through the core of the intercooler, and the cooling efficiency of the intercooler is not necessarily good.

  Here, if the cooling fan dedicated to the intercooler is used to cool only the intercooler independently, and the heat dissipation area of the intercooler is increased and the outer diameter of the cooling fan blades is increased, the noise will be increased. Moreover, the cooling capacity of the intercooler can be increased without reducing the heat balance of the other heat exchangers. However, there is a tendency to increase the size of the upper revolving structure in construction machinery, such as small revolving hydraulic excavators, etc., and an intercooler, a cooling fan, and a hydraulic motor as its driving means are installed on the upper revolving structure. In many cases, it is not possible to secure the space to be used.

  The present invention has been made in view of the above points, and an object of the present invention is to achieve high compression in order to purify the exhaust gas of an engine more and more while environmental pollution prevention is demanded more and more. The cooling capacity of the intercooler can be improved without substantially changing the capacity of the cooling fan or the installation space of the heat exchanger in effectively cooling the supercharged air at a higher temperature to a predetermined level. Is to be able to.

  In order to achieve the above-described object, the present invention cools supercharged air supplied to an engine in an engine room having an engine installation part and a heat exchanger installation part. A plurality of types of heat exchangers including an intercooler are installed, and the heat exchanger and the shroud form a predetermined space, and cooling is performed to flow cooling air that passes through each heat exchanger in the space. In a construction machine in which a fan is provided and an outside air intake portion is formed in a building cover that constitutes the engine room, at least the intercooler is different from other heat exchangers between the outside air intake portion and the cooling fan. It is characterized in that it is arranged at an independent position.

  Since the intercooler in the present invention is disposed independently between the outside air intake section and the cooling fan, the cooling air flowing through the intercooler can be smoothly prevented from being hindered by other heat exchangers such as a radiator and an oil cooler. Since it flows, the supercharged air can be efficiently cooled.

  In addition, by setting the heat dissipation area of the intercooler wider or reducing its thickness, by setting the passage resistance of the cooling air to be smaller than the passage resistance of other heat exchangers, sufficient outside air Intake is possible, and the supercharged air can be efficiently cooled.

  In addition, the intercooler can be disposed at a location where the flow rate of the cooling air between the outside air intake portion and the cooling fan is large by providing the intercooler on the front side of the cooling fan and relatively close to the outer periphery thereof. The supercharged air can be efficiently cooled.

  As the arrangement of each heat exchanger, the intercooler is arranged on the upper surface side in the heat exchanger installation part, and the radiator and the oil cooler in the heat exchanger are arranged in parallel on the front side in the heat exchanger installation part. Can do. As a result, the flow of cooling air in each heat exchanger becomes good, the cooling efficiency of each heat exchanger is improved, the heat balance can be made good, and maintenance such as cleaning of the heat exchanger is facilitated.

  In addition, since a space corresponding to at least the width in the front-rear direction of the intercooler is provided between the rear end of the heat exchanger such as a radiator and an oil cooler and the front end of the cooling fan, the intercooler Cooling air flow that has passed through the radiator and oil cooler can flow smoothly through the cooling fan, and the outside air intake section on the upper surface side where an intercooler with a cooling air passage resistance set smaller than other heat exchangers is arranged Since the outside air can be sufficiently sucked, the supercharged air can be efficiently cooled.

  On the other hand, the heat exchangers are arranged so as to form a substantially triangular shape in plan view by them and the shroud, an intercooler is arranged on one side of the triangle, and a radiator is arranged on the other side. By arranging the oil cooler and the oil cooler, the arrangement space of various devices in the heat exchanger installation part can be made compact. As a result, a battery can be installed on the front and lower portions of the radiator or the oil cooler.

  In the present invention, the capacity of the cooling fan or the space for installing the heat exchanger is effectively reduced by cooling the supercharged air that is in a high temperature state due to high compression to a predetermined level. There are various effects such as the ability to improve the cooling capacity of the intercooler without significant changes.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a hydraulic excavator as an example of a construction machine to which an embodiment of the present invention is applied. In the figure, 100 is a lower traveling body, 101 is an upper revolving body supported on the lower traveling body 100 so as to be able to swivel, and 102 is a work device attached to the upper revolving body 101 so as to be able to move up and down. Reference numeral 1 denotes an engine room constituting the upper swing body 101, 2 denotes an equipment installation room such as a hydraulic valve and an oil tank (not shown), 3 denotes an operation room, and 4 denotes a counterweight.

  2 is a cross-sectional view of the engine room indicated by arrows AA in FIG. 1, FIG. 3 is a plan view of the engine room with the upper cover removed, and FIG. 4 is an external perspective view of the heat exchanger section. is there. In these drawings, the interior of the engine room 1 in the building of the construction machine is partitioned into an engine installation part 5, a heat exchanger installation part 6, and a hydraulic pump installation part 7. An engine 10 is installed on the engine support members 10 a and 10 b in the engine installation unit 5, and a hydraulic pump 11 connected to the engine 10 is arranged in the hydraulic pump installation unit 7. The engine installation unit 5 and the hydraulic pump installation unit 7 are separated by a partition wall 8.

  A heat exchanger is installed in the heat exchanger installation unit 6. As the heat exchanger, a radiator 12, an oil cooler 13, and an intercooler 14 are installed. Furthermore, if necessary, as another heat exchanger, a condenser (not shown) of an air conditioner is installed in series, for example, upstream of the radiator 12 or the oil cooler 13.

  More specifically, outside covers 6 a and 6 b are formed in the front cover 1 a and the upper cover 1 b of the cooling fan 17 described later on the heat exchanger installation part 6 side among the covers constituting the engine room 1. In addition, at the position of the engine installation portion 5, an exhaust portion 5a is formed in the upper cover 1b and the lower cover 1c. These outside air intake parts 6a and 6b and the exhaust part 5a are comprised from a punch board, a louver, etc.

  The outside air intake parts 6a and 6b and the exhaust part 5a are for forming a flow of cooling air inside the engine room 1, and in order to flow this cooling air, the engine installation part 5 and the heat exchanger installation part 6 A cooling fan 17 is provided at the boundary. The cooling fan 17 is driven by the engine 10 via the cooling fan drive unit 20, and when the engine 10 is driven, the cooling fan 17 is also driven to rotate simultaneously. A shroud 21 is provided so as to surround the cooling fan 17. Further, the shroud 21 has extending portions 21a in the four directions in the outer peripheral direction, the anti-circulation wall 22 between the upper cover 1b and the side covers 1d and 1e, and the lower portion of the extending portion 21a at the shielding member 23. The anti-circulation wall is formed between the radiator and the oil cooler via the cooling fan 17, and the cooling air to be exhausted from the engine installation unit 5 side through the cooling fan 17 flows backward and flows into the cooling fan 17. It is configured to prevent. Further, between the radiator 12 and the side cover 1d, between the oil cooler 13 and the side cover 1e, and between the radiator 12 and the oil cooler 13, are shielded by shielding members 25b, 25a, and 25c, respectively. Further, shielding members 25d and 25e are provided between the radiator 12 and the oil cooler 13 and the upper cover 1b, respectively. Here, the shielding members 25c, 25d, and 25e may be provided as necessary. However, these shielding members 25a, 25b, 25c, 25d, and 25e are provided by the outside air from the outside air intake 6a provided on the front cover 1a. Is a shielding member for effectively introducing the gas into the core portion 12c of the radiator 12 and the core portion 13c of the oil cooler 13. Similarly, the intercooler 14 and the side covers 1d and 1e are configured to be shielded by the shielding members 24a and 24b, respectively, so that the outside air from the outside air intake portion 6b provided in the upper cover 1b is effectively interleaved. It is configured to be introduced into the core portion 14 c of the cooler 14. Therefore, as indicated by the arrows in FIG. 2, the outside air is taken into the heat exchanger installation portion 6 from the outside air intake portions 6a and 6b, and the cooling air heat-exchanged with each of the heat exchangers described above becomes the cooling fan 17. Thus, an air flow that is led into the engine installation part 5 through the exhaust and exhausted to the outside through the exhaust part 5a is effectively formed.

  Here, 12a is an upper tank of the radiator 12, 12b is a lower tank, 13a is an upper tank of the oil tank 13, and 13b is a lower tank, respectively. The lower tanks 12 b and 13 b are connected to the upper swing body 101 by the support member T while being connected to an oil tank and a hydraulic valve (not shown). 14a is an inlet portion of supercharged air of the intercooler 14, 14b is also an outlet portion, the inlet portion 14a is connected to the supercharger 15 via an inlet pipe 14d, and the outlet portion 14b is connected to the engine 10 via an outlet pipe 14e. Connected to the air supply section. Reference numeral 15a denotes an air supply / intake section which is connected to an air cleaner (not shown), and 15b is an exhaust pipe for exhausting combustion gas from the engine 10, which is connected to an exhaust muffler 16, and the combustion gas passes through the exhaust pipe 16a. Discharged outside the machine. A supercharger 15 is connected to the exhaust pipe 15b. The supercharger 15 has a turbine. By rotating the turbine at a high speed, the air supplied from the air supply / intake unit 15 a is compressed and supplied to the engine 10. And in order to rotationally drive a turbine, the flow velocity of the exhaust gas which passes along the exhaust pipe 15b is utilized.

  2 and 4, the radiator 12 and the oil cooler 13 are arranged vertically and in parallel with the front surface of the cooling fan 17, and the intercooler 14 is disposed above the front surface of the cooling fan 17 with the core portion 14c. Are arranged horizontally, and no other heat exchanger is interposed between each heat exchanger and the cooling fan 17. In other words, the intercooler 14 is disposed independently between the outside air intake 6 b of the upper cover 1 b and the cooling fan 17 independently of the radiator 12 and the oil cooler 13. Similarly, the radiator 12 and the oil cooler 13 are also disposed independently between the outside air intake 6a of the front cover 1a and the cooling fan 17, respectively.

  Since the intercooler 14 is arranged independently in the upper part in front of the cooling fan 17, the heat radiation area of the core part 14c can be increased. In other words, the engine room 1 can have a length that extends over the entire length of the left and right side covers 1d and 1e. Further, in the forward direction of the cooling fan 17, at least the larger mounting dimension of the radiator 12 or the oil cooler 13 from the distance to the front position where the radiator, the oil cooler, and the intercooler in the prior art are arranged in series. It is possible to secure a width (width in the front-rear direction) up to the amount of subtracting Therefore, since the heat dissipation area of the intercooler 14 can be sufficiently widened compared to the conventional case, the thickness of the core portion 14c of the intercooler 14 can be reduced. Thereby, the ventilation resistance of the intercooler 14 can be made smaller than the ventilation resistance of other heat exchangers.

  Further, in the radiator 12 and the oil cooler 13, since they are arranged in parallel without overlapping between the outside air intake 6a and the cooling fan 17, the length in the direction of the left and right side covers 1d and 1e is about half. However, there is no obstacle to the flow of cooling air other than its own draft resistance, and each heat exchanger is cooled with cooling air at the temperature of the outside air itself, It becomes easy to set each heat balance. Here, reference numeral 26 denotes a battery, which can be disposed on the front surface of the oil cooler 13 at a lower portion of the heat exchanger installation portion by effectively using a space.

  The results of an attempt to simulate cooling air in each heat exchanger configured as described above are shown below. In FIG. 4, the wavy lines (WA1, WB2) drawn in each heat exchanger section schematically show the flow velocity distribution of the cooling air in the embodiment of the present invention. The arrows in FIG. 2 indicate the exhaust air provided in the upper cover 1b and the lower cover 1c after the outside air (cooling air) taken in from the outside air intakes 6a and 6b flows through the heat exchangers and passes through the cooling fan 17. This is a schematic illustration of the discharge from the part 5a.

  The flow velocity distribution of the cooling air in the core portions (12c, 13c) of the radiator 12 and the oil cooler 13 is twice to four in the central portion WA2 with respect to the flow velocity in the vicinity WA1 outside the outer peripheral portion of the opposed axial flow type cooling fan 17. A flow velocity distribution about twice as fast is obtained. Further, in the core portion 14c of the intercooler 14, a certain flow velocity of the cooling air is selected even in the vicinity of the position WB1 that is distant from the cooling fan 17, and in the central portion WB2, the flow velocity distribution is 1.5 to 2 times closer than that. Is obtained. Thus, the cooling efficiency of the intercooler 14 was able to be improved significantly.

  Next, a modification of the embodiment of the present invention will be described with reference to FIG. FIG. 5 is a plan view corresponding to FIG. 3 described above, and shows an outline of the arrangement of each heat exchanger. Components having the same functions as those described above are denoted by the same reference numerals. Description is omitted. In this figure, the intercooler 14 is a plane formed by the intercooler 14 and the radiator 12 and the oil cooler 13 arranged linearly with each other perpendicularly to the heat exchanger installation portion, like the above-described radiator 12 and oil cooler 13. They are arranged in a substantially L-shape, and a substantially triangular shape is formed by these and the extending portion 21 a of the shroud 21. In addition, the intersection of the intercooler 14 and the radiator 12 is disposed obliquely so as to protrude forward of the cooling fan 17. And since the position of the edge part of the oil cooler 13 and the extension part 21a of the shroud 21 is substantially aligned in the forward direction of the cooling fan 17, the oil cooler 13 and the radiator 12 follow the inclination. A battery is placed in the front space. Also in this modified example, the heat dissipation area of the intercooler 14 can be sufficiently wide because a long distance can be secured in the vertical direction, and the passage resistance of the cooling air is set sufficiently small by reducing the thickness of the core portion 14c. can do.

  The arrows in FIG. 5 indicate the flow of the cooling air. As can be seen, the cooling air from the outside air intake 6a provided on the front cover 1a passes through each heat exchanger and then exchanges other heat. The engine is arranged to be exhausted through the cooling fan 17 without being obstructed by the vessel. Here, 28 denotes a shielding member between the intercooler 14 and the extending portion 21a of the shroud 21, and the cooling air taken in from the outside air taking-in portion 6a as described above passes through the core portion of each heat exchanger. To the cooling fan 17.

  By adopting such a configuration, the cooling efficiency of the intercooler 14 can be improved as described above, and the space of the heat exchanger installation portion 6 can be used effectively. In other words, the heat exchanger installation part 6 can be made compact.

1 is an external side view of a hydraulic excavator to which an embodiment of the present invention is applied. It is sectional drawing of the engine room shown by arrow AA of FIG. FIG. 3 is a plan view excluding an upper cover in FIG. 2. It is a diagonal bird's-eye view of a heat exchanger part. It is the same top view as FIG. 3 which shows the modification of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine room 5 Engine installation part 5a Exhaust part 6 Heat exchanger installation part 6a, 6b Outside air intake part 10 Engine 12 Radiator 13 Oil cooler 14 Intercooler 14d Inlet pipe 14e Outlet pipe 15 Supercharger 15a Intake air intake pipe 15b Exhaust pipe 17 Cooling fan 21 Shroud 21a Shroud extension 22 Circulation prevention wall 23, 28 Shielding member 24a, 24b Shielding member 25a, 25b Shielding member 26 Battery

Claims (8)

In an engine room equipped with an engine installation section and a heat exchanger installation section, a plurality of types of heat exchangers including an intercooler that cools supercharged air supplied to the engine are installed in the heat exchanger installation section. The heat exchanger and the shroud form a predetermined space, and a cooling fan is provided in the space to allow cooling air to pass through each of the heat exchangers. Further, the building cover that constitutes the engine room In the construction machine that formed the outside air intake,
A construction machine having an air-cooled intercooler, wherein at least the intercooler is arranged at a position independent of other heat exchangers between the outside air intake section and the cooling fan. The said other heat exchanger is comprised with the radiator and the oil cooler, and the passage resistance of the cooling air to the said intercooler was set smaller than the passage resistance of these other heat exchangers, Construction machine with air-cooled intercooler. The construction machine having an air-cooled intercooler according to claim 1, wherein the intercooler is disposed at a location where a flow velocity of cooling air between the outside air intake portion and the cooling fan is large. The construction machine having an air-cooled intercooler according to claim 1, wherein the intercooler is disposed in the vicinity of the outside air intake portion. The intercooler is arranged on the upper surface side in front of the cooling fan in the heat exchanger installation part, and the radiator and the oil cooler which are other heat exchangers are arranged in parallel on the front side in the heat exchanger installation part. The construction machine having the air-cooled intercooler according to claim 1, wherein the construction machine is configured. The space between the rear end portion of the heat exchanger such as the radiator and the oil cooler and the front end portion of the cooling fan is provided with at least a space corresponding to the width in the front-rear direction of the intercooler. 5. A construction machine comprising the air-cooled intercooler according to 5. The heat exchanger and the shroud are arranged so as to form a substantially triangular shape in plan view, the intercooler is arranged on one side of the triangle, and the radiator and the oil cooler are arranged on the other side. The construction machine provided with the air-cooling type intercooler according to any one of claims 1 to 6, wherein: 8. The construction machine having an air-cooled intercooler according to claim 7, wherein a battery is installed on a front part and a lower part of a radiator or an oil cooler installed in the heat exchanger installation part.

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