瑞典专利SE533908C2 Cooling device for a fluid in an internal combustion engine and its use

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公开号:SE533908C2
申请号:SE0801726
申请日:2007-01-24
公开日:2011-03-01
发明作者:Ohsawa Akihiro；Tsujimura Shinji；Chiyo Ninzai；Hiraki Hikosaburou
申请人:Komatsu Mfg Co Ltd；
IPC主号:

专利说明:

53 30 H08 2 arranged in the vicinity of the radiator 8. The radiator cooling fan 9 blows air towards the radiator to cool the coolant passing in the radiator 8. The wind draft generated by the radiator cooling fan 9 passes through the radiator 8 and the temperature of the wind draft becomes higher because it absorbs heat from the radiator 8. After passage through the radiator 8, the wind draft is moved in a direction opposite the radiator cooling fan 9 with respect to the radiator 8.
In the same way, a cooling passage is also arranged at the EGR cooler 5. This cooling passage communicates with the radiator 8 by means of the passage 7. Thus, the cooling medium which passes through the EGR cooler 5 is also cooled by the radiator 8.
In other words, a part of the coolant used for cooling the engine 1 is used as the coolant for the EGR cooler 5. The coolant heated by the heat exchanger with the EGR gas in the EGR cooler 5 is combined with the coolant heated as a result of cooling of motor 1, and is led to the radiator 8.
The technique described above, in which a part of the engine coolant is led to the EGR cooler 5 for cooling the EGR gas, is described in the background technique in the patent literature 1.
It has been shown that a larger amount of EGR has been required to further reduce NOx. The amount of heat required to cool the large amount of EGR gas thus increases, necessitating a larger capacity and size of the EGR cooler 5, the radiator 8, the radiator cooling fan 9, a water pump or other cooling units. As a result, large spaces in the engine compartment have been required to accommodate these engine cooling units, which has a major impact on vehicle design.
However, there is a requirement that the cooling capacity must be maintained and at the same time keep the cooling units so that the radiator is small, even if the amount of EGR gases increases.
In order to meet the above requirements, the patent literature 1 above provides an invention for increasing the cooling efficiency without enlarging the radiator, and this by a principle of boiling and condensing. In other words, with the principle of boiling and condensing, the patent literature 1 describes an invention for reducing the number of tubes connecting the evaporator to a condenser as much as possible and eliminating the need for a circulation pump by using gravity as driving force to circulate the condensed ﬂuide to an evaporator. In this invention, the condenser is located above the evaporator; the condenser and the evaporator are connected to the pipes for the steam and the condensed fluid; the refrigerant evaporates to steam in the evaporator; the steam is led to the condenser, which is located above the path of the steam pipe; the steam is condensed to ﬂ uiden in the condenser; and the condensed fluid is dropped to the evaporator below by means of the tube of the condensed fluid by means of gravity. In accordance with the invention above, it becomes possible to keep the radiator and other cooling units in the existing size, and the circulation pump for circulating the steam becomes superfluous.
The patent literature 2 shows another method for using the principle of boiling and condensing. In this invention, the condenser is in direct communication with the evaporator, which is located above, without the use of any pipe, and passages for steam and the condensed fluid are arranged separately. The steam generated in the evaporator is led to the passage for steam placed above without the use of any pipe and the steam is moved. Pressure losses caused by the vapor displacement are thus smaller than those according to the invention in the patent literature 1. In addition, the fluid condensed in the area located above falls through the passage of the condensed fluid without passing through the pipe, whereby the pressure loss caused by the fall can be reduced compared with the patent literature. 1. As a result, the pressure loss caused by circulation of a medium can be reduced, whereby the medium circulates evenly. In addition, since the passage of vapor and that of the condensed fluid are separated, the fall of the condensed fluid can be prevented from being blocked by the vapor entering the passage of the condensed fluid, allowing the medium to circulate efficiently. Thus, it is possible to improve the thermal transfer performance as compared with the technology according to the patent literature 1.
The common denominator of the inventions according to patent literature 1 and 2 is that both inventions use gravity to circulate the medium. In the case where gravity is used to circulate the medium, it is important to separate the passage for the steam and that for the condensed fluid. In addition, another problem with the above-mentioned prior art, which uses gravity to circulate the medium, is in addition that the thermal transfer performance deteriorates significantly at a certain state. In a state where the cooling unit is inclined, the circulating force of the condensed fluid becomes equal to the gravitational component acting parallel to an inclined surface, which results in a significant reduction of the circulating force. This causes a serious problem, especially in a case of the application of a construction machine. The construction machine can also be used at an inclination of 30 degrees. In the technique described above which uses gravity as a circulating force, due to the reduction in the circulating force, the heat radiation becomes insufficient when the construction machine is inclined 30 degrees, whereby the temperature of the working medium increases. Thus, the pressure of the medium suddenly increases, which can damage the EGR cooler.
Pat. the size of the device can be minimized; and the circulation pump will not be needed. On the other hand, there is a problem of significantly limiting the thermal transfer performance in a case using the method described above, which uses the gravity for the circulation of the medium.
As another method of improving the thermal transfer performance using the principle of boiling and condensation, a device has been proposed, as shown in fig. 2, which uses a meander tube as a heating tube 100 which uses a principle of self-generating vibration.
As shown in fig. 2, the heating tube 100 is formed by bending a thin tube several times, and the heating medium is enclosed in the heating tube 100. In this method, the vibrating force is used as a driving force to circulate the heating medium, whereby a significant improvement of the thermal transfer performance can be expected.
In the cooling device, which uses the heating tube 100, however, the heat exchange is carried out while a cooling medium moves in the single, thin tube. The amount of heat transport becomes small in this device, since a rapid increase in the flow resistance as a result of an increase in the thermal load prevents the movement of the refrigerant, namely the thermal movement. This device is thus not suitable for cooling a large amount of a cooling object which has a high temperature, such as exhaust gas.
The present invention has been carried out in the light of the conditions described above, and the problem to be solved by the present invention is to, without enlarging the cooling units, such as the radiator, eliminate the need for the pipes connecting the evaporator to the condenser as well as the steam circulation pump; improve the thermal transfer performance by using, as a circulating force, the vibrating force instead of gravity; and allowing a large amount of heat transport from the object to be cooled, which has a high temperature, such as the exhaust gases. Means for solving the problems A first aspect of the present invention provides a cooling device for a fluid, which comprises: an endoergic side of the heat exchanger having a ﬂ uid passage for passing a fluid to be cooled and storing a cooling medium for cooling the ﬂ uid by heat exchange with the fluid in the fluid passage; an exoergic side of the heat exchanger having at least two refrigerant passages, one end of the at least two refrigerant passages communicating with the endoergic side of the heat exchanger and the other end of the at least two refrigerant passages communicating with each other; and refrigerant cooling the refrigerant passing on the exoergic side of the heat exchanger by heat exchange with the refrigerant, in which the cooling device is designed to recirculate the refrigerant between the endoergic side of the heat exchanger and the exoergic side of the heat exchanger, the refrigerant passages or the like having a passage 10 15 20 25 30 533 308 6 diameter ranging from 2 mm to 16 mm, and the entire coolant passage is formed with a substantially uniform diameter or equivalent diameter.
A second aspect of the present invention provides the cooling device for the ui according to the first aspect of the invention, in which an EGR passage supplying exhaust gases in an engine exhaust passage to an intake passage is provided, and the exhaust gases passing through the EGR passage pass through the endoergic side of the heat exchanger .
A third aspect of the present invention provides the fluid cooling device according to the first aspect of the invention, in which a turbocharger compressing the intake air and introducing the compressed intake air into an engine intake passage is provided, and the intake air compressed by the turbocharger passes through it. endoergic side of the heat exchanger as the fluid to be cooled.
A fourth aspect of the present invention provides the fluid cooling device according to any of the first to third aspects of the invention, in which the cooling means is a cooling fan.
A fifth aspect of the present invention provides the fluid cooling device according to the fourth aspect of the invention, further comprising: a radiator through which an engine coolant passes; and a radiator cooling fan, in which the radiator cooling fan is arranged as a cooling means.
A sixth aspect of the invention provides the fluid cooling device according to the first aspect of the invention, in which a ratio of the volume of coolant to the volume of the endoergic side of the heat exchanger and the exoergic side of the heat exchanger is set to a prescribed volume ratio ranging from 20% to and by 80%.
A seventh aspect of the present invention provides a fluid cooling device, in which the fluid cooling device according to the first aspect of the invention comprises: several separate endogenous sides of heat exchangers; several separate exogenous sides of heat exchangers, each corresponding to the number of separate endoergic sides of heat exchangers, in which the fluid passages in the plurality of separate endoergic sides of the heat exchangers each communicate in series, and a boiling point of the refrigerant in each of of separate endoergic sides of the heat exchangers is set to gradually decrease as a position of the fluid passage goes upstream to downstream.
An eighth aspect of the present invention provides the cooling device for enligt uid according to the seventh aspect of the invention, in which each of the plurality of separated endoergic sides of the heat exchangers is divided by a partition wall which allows the fluid to be cooled to pass the connecting endoergic side of the heat exchangers and allows not the refrigerant to pass the connecting endoergic side of the heat exchanger.
A ninth aspect of the present invention provides the fluid cooling device according to the fourth aspect of the invention, further comprising: a radiator through which an engine cooling medium passes; and a radiator cooling fan, in which the cooling fan is separately arranged as the cooling medium in addition to the radiator cooling fan.
A tenth aspect of the present invention provides a fluid cooling device according to the fourth aspect of the invention, in which the exoergic side of the heat exchanger is annularly formed, and the cooling fan is arranged as the cooling means inside the exoergic side of the heat exchanger formed with an annular shape.
An eleventh aspect of the present invention provides the fluid cooling device according to the tenth aspect of the invention, in which the cooling device is located above the engine.
A twelfth aspect of the present invention provides the cooling device for a fluid, comprising: an endoergic side of the heat exchanger having an outlet passage for the passage of a fluid to be cooled and storing a cooling medium for cooling the fluid by heat exchange with the fluid in the fluid passage; an exoergic side of the heat exchanger having at least two refrigerant passages, one end of the at least two refrigerant passages communicating with the endoergic side of the heat exchanger and the other end of the at least two refrigerant passages communicating with each other; and refrigerant cooling the refrigerant passing the exoergic side of the heat exchanger by heat exchange with the refrigerant, in which the refrigeration device is designed to recirculate the refrigerant between the endogenous side of the heat exchanger and the exoergic side of the heat exchanger, and the refrigerant passages in which evaporated at the endoergic side of the heat exchanger by absorbing heat of the fluid, and the refrigerant which becomes liquid in the exoergic side of the heat exchanger exchanging heat is absorbed by the cooling means.
Effects of the invention The cooling device according to the present invention has at least two passages for a cooling medium. Other ends of the two coolant passages communicate with each other, and both coolant passages have substantially the same diameter or an equivalent diameter. By making the diameter or the equivalent diameter of the refrigerant passages from 2 mm to 16 mm, it becomes possible to produce self-generated vibration. The equivalent diameter here refers to a diameter in which the fluid resistance of the passages is the same in a case where the cross section of the refrigerant passage which does not have a round shape is represented by a round shape.
In the present invention, both the vaporized steam which alters the absorption of the heat of the fluid in an endoergic side of the heat exchanger and the refrigerant which has become liquid in the exoergic side of the heat exchanger can pass through the at least two refrigerant passages. This allows a reduction of the fluid resistance. The condensed fluid is thus reversed faster than that of gravity alone, whereby the amount of heat transport can be increased several times.
In the present invention, since the vibrational force is used as the driving force to circulate the coolant, it is unlikely to be affected by gravity. Thus, the deterioration of the thermal transfer performance can be prevented even in the inclined situation. In the present invention, a passage for the fluid (exhaust gases) is formed within the endogenous side of the heat exchanger. Thus, an endothermic surface between the fluid (exhaust gases) and the coolant becomes large. This allows the significant increase in the amount of heat stuffing. Therefore, the amount of heat transport becomes large, whereby the large amount of heat from the cooling object, which has a high temperature, such as the EGR gas, can be efficiently cooled.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing the prior art and showing a configuration of an EGR cooler for cooling; Fig. 2 is a diagram illustrating the prior art and showing a configuration of a heating tube using self-generating vibration; Fig. 3 is a diagram showing the relationship between an EGR cooler according to the embodiment and other components; F ig. 4A and 4B are sketches showing a configuration of the EGR cooler according to the embodiment; Figs. 5A to 5D are sketches showing embodiments of EGR coolers different from the EGR cooler shown in Figs. 4A and 4B; Figs. 6A to 6C are graphs showing experimental data associated with the EGR cooler according to the embodiment; Figs. 7A and 7B are diagrams showing examples of how the EGR cooler, a radiator and a radiator cooling fan, shown in Fig. 6, are positioned relative to each other; Figs. 8A to 8C are conventional sketches of an EGR cooler having configurations different from the EGR cooler shown in Figs. 4A and 4B, the EGR cooler being provided with a cooling fan; Fig. 9 is a sketch showing how an engine and the EGR cooler shown in fig. 8 are positioned relative to each other; Figs. 10A and 10B are diagrams explaining the cooling capacity in comparison; and Fig. 11 is a diagram showing the appearance configuration of the EGR cooler. BEST MODE FOR CARRYING OUT THE INVENTION Referring now to the drawings, an embodiment of an kyluid cooling device according to the present invention will be described.
Fig. 3 shows a sketch of an engine compartment of a construction machine according to an embodiment.
As shown in ﬁ g. 3, an exhaust passage 2 and an intake air passage 3 in an engine 1 communicate by means of an EGR passage 4.
An EGR cooler 15 is arranged for the EGR passage 4. In the EGR passage 4, an EGR gas 30, which is a cooling object for the EGR cooler 15, is introduced from the exhaust passage 2 and the EGR gas 30 passes through it. The EGR cooler 15 is a cooling device for cooling the EGR gas 30 to be cooled, and is arranged for the purpose of reducing NOx and further, without impairing the engine power by lowering the temperature of the EGR gas 30, which flows in the intake passage 3 through the EGR passage 4 to increase the charging power of the gas flowing into a cylinder of the engine 1.
In the engine 1 a cooling passage 6 is formed for the passage of a cooling medium. By means of the passage 7, the cooling passage 6 communicates with a radiator 8 in order to lower the temperature of the coolant by heat exchange with external air. In general, the temperature of the refrigerant is around 80 ° C. A radiator cooling fan 9 is arranged in the vicinity of the radiator 8. The radiator cooling fan 9 blows air from the outside to the radiator 8 to cool the coolant passing the radiator 8. The cooling air blown to the radiator 8 is around 30 ° C. After the passage through the radiator 8, the air is led to the EGR cooler 15, where the cooling air 21 has a high temperature of about 70 ° C.
Figs. 4A and 4B show a design of the EGR cooler 15.
Fig. 4A is a perspective view of the EGR cooler 15. Fig. 4B shows a sectional view taken along the line A-A in Fig. 4A. As shown in Figs. 4A and 4B, the EGR cooler 15 comprises an endoergic side of the heat exchanger (cooking section or evaporator section; evaporator) 16 and an exoergic side of the heat exchanger (condensing section; condenser) 17. In this embodiment, the EGR gas 30 flowing in the EGR passage 4 passes inside the endurgical side of the heat exchanger 16.
A storage reservoir 18 for the refrigerant is formed in the endoergic side of the heat exchanger 16 to surround the EGR passage 4. Within the endoergic side of the heat exchanger 16, the EGR passage 4 is divided into the plurality of EGR passages 4a, 4a, as shown in Figs. 4. inside the endoergic side of the heat exchanger 16, the storage reservoir 18 for the refrigerant is formed so as to surround the plurality of EGR passages 4a, 4a. In the storage reservoir 18 for the refrigerant is a cooling medium 20 for cooling the EGR gas 30 by heat exchange with the EGR gas 30 present in each of the plurality of EGR passages 4a, 4a, stored.
In addition, flanges 4b, 4b, are provided at each of the number of EGR passages 4a, 4a. As described above, since the storage reservoir 18 for the refrigerant is formed so as to surround the plurality of EGR passages 4a, 4a, the flanges 4b, 4b, are arranged, the area where the coolant 20 comes into contact with an outer surface of the EGR passage 4 can be large. This allows a large heating surface between the EGR gas 30 and the coolant 20, in order to thereby realize efficient heat exchange.
It should be noted that as a method of making the heating surface large, several tubes can be provided in the EGR passage shown in Fig. 4B.
The exoergic side of the heat exchanger 17 is provided with three coolant passages 19, 19, 19. For the coolant passages 19, a tube can be used, as shown in ﬁ g. 4A and 4B. As an example of the pipe above, a thin pipe made of aluminum or copper can be used, but the pipe is not limited to this example. One end of these refrigerant passages 19, in other words, lower ends of these refrigerant passages 19 communicate with the refrigerant storage reservoir 18 in the endoergic side of the heat exchanger 16. On the other hand, the other ends of these refrigerant passages 19 communicate , in other words, the upper ends of these coolant passages 19 with each other with a common coolant passage 19a.
To the outer surfaces of both the coolant passages 19 and the common coolant passage 19a, flanges 23 are formed for the purpose of heat exchange with the outer air.
The cooling air 21 passing through the radiator 8 and having a high temperature around 70 ° C flows in at a cooling air flow surface 17A of the exoergic side of the heat exchanger 17. Thereafter, the heat exchange between the cooling air 21 and the coolant 20 in the coolant passages 19 and the common coolant passage 19a using the flanges 23.
The operation of the EGR cooler 15 according to this embodiment described above will be described.
As shown in fig. 4B, the refrigerant 20 in the refrigerant storage reservoir 18 at the endoergic side of the heat exchanger 16 absorbs heat from the EGR gas 30, which flows in the divided EGR passages 4a, 4a, 4a, and thereafter the refrigerant vapor 20G occurs randomly by phase conversion. This vapor accumulates in the upper part of the endoergic side of the heat exchanger 16. At this time, due to a rapid expansion of the volume of the refrigerant 20, the pressure increases in the endoergic side of the heat exchanger 16. On the other hand, in the exoergic side of the heat exchanger 17, when the refrigerant vapor 20G condenses to a liquid phase due to the cooling effect with the cooling air, and its volume is reduced, the pressure decreases locally. To compensate for this local pressure difference, the refrigerant vapor 20G, which is present in the endoergic side of the heat exchanger 16, flows into each of the refrigerant passages 19 in the exoergic side of the heat exchanger 17. The refrigerant passages 19, 19, 19 communicate with each other. by means of the common coolant passage 19a. Thus, when the refrigerant 20 in any of the refrigerant passages 19 moves upward, the refrigerant 20 in other refrigerant passages 19 thus moves downward. The refrigerant 20 returned to the endoergic side of the heat exchanger 16 and the excess steam 20G are separated into gas and liquid. Thereafter, the refrigerant 20 is heated again while the refrigerant vapor 20G together with newly generated refrigerant vapor 20G flows into the exoergic side of the heat exchanger 17 due to the local pressure difference as above. As described above, in the endoergic side of the heat exchanger 16 and each of the refrigerant passages 19, depending on the local pressure difference which changes randomly with time, in other words, self-generating vibration, the refrigerant 20 and the refrigerant vapor 20G vibrate by self-generating in each one of the refrigerant passages 19 in the exoergic side of the heat exchanger 17 and in the common refrigerant passage 19a shown by an arrow.
Through the operation above, both latent heat in a vapor phase and sensible heat in a liquid phase are transported simultaneously. In the following, conditions for producing self-generated vibration will be described.
As a first condition, a diameter d of each refrigerant passage 19 shall be described.
Fig. 6B shows the relationship between the diameter d and the thermal load e.
The thermal load e is equivalent to the amount of heat transport, and can also be referred to a thermal transfer performance.
In one experiment, in order to obtain the thermal load e, a length of each of the refrigerant passages 19 is set to 200 mm, while the diameter d of the refrigerant passage 19 varies in the range from 10 mm to 20 mm. In the prior art in which self-generated vibration does not occur, it is known that the thermal load e is about 0.3. Considering that the amount of heat transport is equal to the thermal load e, it is understood from the experimental result that it is possible to obtain 2-3.3 times increase of the amount of heat transport compared to the prior art by setting the equivalent diameter of each of the refrigerant passages to 2-16 mm. In particular, by setting the equivalent diameter from 3 mm to 13 mm, the amount of heat transport becomes 0.8 or more, and better efficiency can be obtained. As a second condition, a method of controlling the volume of cooling air to produce the self-generating vibration shall be discontinued.
Fig. 6C shows a measurement result of a relationship between the volume of cooling air and the thermal load e in the embodiment described above. As can be understood from this graph, there is a volume of cooling air in which the thermal load ends up around the maximum value. In this case, by controlling the number of revolutions of the cooling shaft so that the volume of the cooling air is about 50% of the maximum air volume, it becomes possible to handle the maximum thermal load.
As described above, in this embodiment, the refrigerant is circulated by the self-generating vibration. Since the vibrational force through the self-generation is used as a driving force to circulate the coolant 20, it is unlikely to be affected by gravity. Thus, unlike the prior art, the thermal transfer performance is less likely to be limited.
In addition, the heat exchange is not performed by using a simple thin tube as described with the heating tube 100 in Fig. 2, but by forming the passages 4a for the exhaust gases 30 inside the endorergic side of the heat exchanger 16 and forming the refrigerant storage reservoir 18 so as to surround the passages 4a. Thus, the heating surface between the exhaust gases 30 and the coolant 20 becomes large, thereby significantly improving the amount of heat input. This allows the increase in the amount of heat transport, whereby the large amount of heat can be efficiently cooled even in a case where the substance to be cooled has a high temperature, such as the exhaust gases 30. In the following it will be described that, with the present invention, the size of the radiator or other refrigeration units remain unchanged with respect to existing size, and an enlargement is not necessary.
In the prior art shown according to 1, an engine cooling medium whose temperature increases as a result of the cooling of the EGR gases flows into the radiator at about 80 ° C, and is cooled with the cooled air at about 30 ° C supplied by the cooling fan. In this case, the temperature difference (air-water-temperature difference) between the engine coolant and the cooling air is about 50 ° C. Using this temperature difference, the engine coolant is cooled.
The cooling air 21, after passing through the radiator 8, reaches a high temperature of about 70 ° C. Thus, since the air-water temperature difference for cooling the engine coolant is only about 10 ° C, the coolant is not particularly cooled by the engine coolant having 80 ° C.
Since the principle of boiling and condensation is used in the cooling device (EGR cooler 15) according to the present invention, the cooling medium 20 boils. For example, when water is used as cooling medium, the water boils at 100 ° C under a pressure of 1 atmosphere, and at 150 ° C below an internal pressure of 5 atmospheres. When the refrigerant 20 circulates forcibly through the self-generating vibration, the refrigerant 20 boils at the exoergic side of the heat exchanger at the same temperature as at the endorergic side of the heat exchanger, for example 150 ° C.
Thus, since the exoergic side of the heat exchanger of the EGR cooler 15 of the present invention reaches 150 ° C even if the temperature of the cooling air 21 after passing through the radiator 8 is 70 ° C, it becomes possible to obtain the air-water temperature difference of 80 ° C. ° C. In the conventional technique, even if the cooling air has a temperature of 30 ° C, the air-water temperature difference reaches as low as 50 ° C. On the other hand, the EGR cooler of the present invention can obtain the cooling capacity of 1.6 times higher than that of the prior art, even by using air having 70 ° C after passing through the radiator, which is considered as air, which is not has some cooling capacity, namely spent air according to the prior art.
As a result, the existing radiator or other cooling devices can be used without modification, and the enlargement is not necessary.
Furthermore, according to this embodiment, the EGR cooler 15 has a configuration in which the exoergic side of the heat exchanger 17 communicates directly with the endogenous side of the heat exchanger 16, and the self-generating vibration, rather than gravity, is used to circulate the coolant 20. Thus, the tubes which connects the evaporator (the endoergic side of the heat exchanger 16) to the condenser (the exoergic side of the heat exchanger 17) and the circulation pump to circulate the steam is not necessary.
Figs. 5A and 5B show an example of a configuration of an EGR cooler 15 having a different appearance from the EGR cooler 15 shown in FIG. In Figs. 5A and 5B, the components having identical features are designated as the components forming the EGR cooler 15 shown in Fig. 4, identical reference numerals.
As shown in Figs. 5A and 5B, the configuration of the endoergic side of the heat exchanger 16 is different from that shown in Fig. 4, and is formed with a cylindrical shape in which the EGR passage 4 (each divided EGR passage 4a) covered.
The exoergic side of the heat exchanger 17 is formed with a rectangular shape.
The EGR cooler 15, shown in Figs. 5A and 5B, has a configuration in which the coolant passages 19, 19 are arranged along the longitudinal direction of the EGR passage 4, the exoergic side of the heat exchanger 17 being formed with a thin wall W.
Figs. 7A and 7B show a relationship regarding the position between the radiator 8 and the radiator cooling fan 9.
The description above has been carried out by giving an example where the EGR gas is the fluid to be cooled. However, the fluid of the present invention is not limited to the EGR gas.
A case where engine oil is used as the fluid to be cooled shall be described.
An oil cooler 40 used for the engine and work equipment is arranged parallel to the radiator 8, which is not shown in Fig. 3. Fig. 5C is a schematic view of the oil cooler 40. The construction of the oil cooler 40 is similar to the radiator 8. Although the engine coolant passes in the radiator , the oil passes in the oil cooler 40. Since reinforcement of the entire oil cooler is needed to prevent oil leakage and the like, due to the high oil pressure, the main difference is that the weight is greater and the manufacturing cost is higher than for the radiator. By passing the oil in the fluid passage (corresponding to the passage of the EGR gases in the EGR cooler), which is the substance to be cooled, in the endoergic side of the heat exchanger, which has the structure of the EGR cooler shown as examples in Figs. 5A and 5B, it can be used as the oil cooler. In this fail, since a portion through which the oil passes can be reduced to 1/3 level compared to the conventional oil cooler, a portion requiring the high, strong structure can be reduced to 1/3 level compared to the conventional type, whereby a light and cost-effective oil coolers can be provided.
According to the next embodiment, a case where the inlet air compressed by means of a torbo charger is used as the substance to be cooled will be described. In Fig. 3, a turbocharger 10 is arranged at the engine 1. The turbocharger 10 is arranged to improve the fuel efficiency, the power of the engine and so on. An inlet of a housing to the turbine 11 of the turbocharger 10 communicates with the exhaust passage 2, while an outlet of the housing of the turbine 11 communicates with the outside air through a muffler 22. An inlet of a housing to a compressor 12 of the turbocharger 10 communicates with the outside air through an air purifier 13, while an outlet of the compressor housing communicates with the inlet passage 3 through an aftercooler 14. The aftercooler 14 is arranged to reduce the temperature of the inlet air compressed by the turbocharger 10 to improve the charging efficiency of oxygen in the cylinder of the engine 1 .
It may be possible to apply the present invention with the aftercooler. Fig. 5D shows a schematic view of an aftercooler. By allowing the inlet air compressed by the turbocharger 10 to pass through the fluid passages, which are the substances to be cooled by the endoergic side of the heat exchanger 16, they can be used as aftercoolers. the inlet air compressed by the turbocharger 10 reaches 150 ° C under a pressure of 3 atmospheres, which is a relatively high temperature and high pressure. However, by applying the above technique, since the portion exposed to the high temperature and pressure can be reduced to about 1/3, the aftercooler can be made light and cost effective as in the case of the previous embodiment above. Fig. 6A shows the relationship between the amount of heat transport C and. the volume ratio B of the refrigerant 20 in a liquid solid state to the total volume of the endoergic side of the heat exchanger 16 and the exoergic side of the heat exchanger 17, in other words, the total volume of the refrigerant storage reservoir 18, the refrigerant passages 19, 19, and the common refrigerant passage 19a.
As shown in Fig. 6A, under the range of the volume ratio B from 20% up to and including 80%, the amount of heat transport C becomes a sufficient level or higher to cool the exhaust gases 30, which have a high temperature. Preferably, the volume ratio B of the refrigerant 20 is set from the range of 20% up to and including 80%.
Figs. 7A and 78 show how the radiator 8 and the radiator cooling fan 9 are positioned relative to each other.
I ﬁ g. 7A, the radiator 8 is located in the rear direction of the radiator cooling fan 9, and the EGR cooler 15 is located in a rear direction of the radiator 8. With the radiator cooling fan 9, the cooling air 21 is delivered to and passes through the radiator 8; and the coolant 20 or coolant vapor 20G in the exoergic side of the heat exchanger 17 of the EGR cooler 15 is cooled by the cooling air 21, which has the high temperature emitted backwards from the radiator 8.
In addition, ifig. 7B, the EGR cooler 15 is located in the rear direction of the radiator 8, and the radiator cooling fan 9 is located in the rear direction of the EGR cooler 15. By drawing the front air with the radiator cooler 9, the cooling air 21 is delivered to and passes through the radiator 8. ; and the coolant 20 in the exoergic side of the heat exchanger 17 of the EGR cooler 15 is cooled by the cooling air 21, which has the high temperature emitted backwards from the radiator 8.
In the above embodiments, as means for cooling the EGR cooler 15, the radiator cooling fan 9 is used for cooling the coolant of the engine 1. However, any means for cooling can be used as a coolant for cooling the EGR cooler 15. Example 15 In addition to the radiator cooling fan 9, a cooling fan intended to supply the cooling air 21 to the EGR cooler 15 can be provided.
With reference to ﬁ g. 8, an embodiment according to the configuration above shall be described.
In Fig. 8, the exoergic side of the heat exchanger 17 is formed in an annular shape.
Fig. 8A is a perspective view of the EGR cooler 15, and Fig. 8B shows a cross-sectional view taken along the line B-B along the circle of the EGR cooler 15, shown in Fig. 8A.
Components that have identical features to the components that make up the EGR cooler 15, shown in Fig. 4, are designated by identical reference series.
In Fig. 8, the exoergic side of the heat exchanger 17 is formed in an annular shape. However, it may have a polygonal and annular shape. In the EGR cooler 15 according to this embodiment, an annular cooling ﬂ genuine 24 is similarly arranged inside the annular exoergic side of the heat exchanger 17 as coolant. The cooling vessel 24 is arranged as a supplement to the radiator cooling unit 9.
The cooling fan 24 drives external air from above (or from an outer wall surface 17B), and the cooling air 21 is supplied to each part of an inner wall surface 17A of the annular exoergic side of the heat exchanger 17. The cooling air 21, which passes through the annular exoergic side of the heat exchanger 17 is released from the outer wall surface 17B (or from above). In the device according to this embodiment, in addition to the radiator cooling fan 9, a cooling fan 24 for the EGR cooler 15 is arranged. Thus, in this embodiment, it becomes possible to place the EGR cooler 15 in the vicinity of the EGR passage 4 without any local limitation with respect to the radiator cooler 9.
As in the case of Fig. 8B, ﬁ g. Fig. 8C is a sectional view taken along the line B-B along the circle of the EGR cooler 15 shown in Fig. 8A. The endoergic side of the heat exchanger 16 comprises a plurality of separated endoergic sides of heat exchangers 16A, 16A, 16A, each having a separate refrigerant storage reservoir 18A, 18A, 18A. In addition, the exoergic side of the heat exchanger 17 comprises a plurality of separate exoergic sides of heat exchangers 17A, 17A, 17A, each corresponding to each of the plurality of separated endoergic sides of heat exchangers 16A, 16A, 16A. Each of the endoergic sides of the heat exchangers 16A, 16A, 16A is separated by partitions 16B, 16B which allow the EGR gases 30 to flow into the connecting endoergic side of the heat exchanger 16A and do not allow the refrigerant 20 to flow into the adjacent endoergic side of the heat exchanger 16A.
The EGR passages 4c, 4c, 4c in the endoergic side of the heat exchangers 16A, 16A, 16A communicate in series with each other and form the EGR passage 4.
The boiling points of the refrigerants 20 in the refrigerant storage reservoirs 18A, 18A, 18A in the endoergic sides of the heat exchangers 16A, 16A, 16A are each set to the temperatures T1, T2, T3, which gradually decrease (T1> T2> T3) at a position upstream of downstream of EGR passages 4c, 4c, 4c.
Figs. 10A and 10B show schematic diagrams each showing a case where a single EGR cooler 15 is arranged to the EGR passage 4 and a case where ﬂ your (two) EGR coolers 15 are arranged in series, and show the comparison of cooling capacity.
First, as shown in Fig. 10A, the case where the only EGR cooler 15 is provided to the EGR passage 4 will be described.
By setting the cooling point of the coolant 20 in the coolant storage reservoir 18 to 140 ° C, the EGR gases 30 flowing into the inlet of the EGR cooler 15 are cooled at 540 ° C, and flow out of the EGR cooler 15 at 165 ° C. It should be noted that it is assumed that the temperature of the cooling air 21 is 70 ° C. On the other hand, as shown in Fig. 10B, the case will be described where several (two) EGR coolers 15 are arranged in series. It is assumed that the boiling point Ti of the refrigerant 20 in the refrigerant storage reservoir 18, which is located upstream of the EGR cooler 15 of the EGR passage 4 is set to 180 ° C; the boiling point T2 of the refrigerant 20 in the refrigerant storage reservoir 18, which is located downstream of the EGR cooler 15 of the EGR passage 4 is set to 110 ° C; and the temperature of the EGR gases 30 at the inlet upstream of the EGR cooler 15 is set to 540 ° C, which is the same temperature as shown in Fig. 10A. The EGR gases flowing in at 540 ° C are cooled upstream and downstream of the EGR coolers 15, and flow out from the side downstream of the EGR cooler at a temperature of 150 ° C. This allows further reduction of the temperature of the EGR gases 30 in comparison with the configuration shown in Fig. 10A.
In general, between the number of N steps at which the endoergic side of the heat exchangers 16A is connected in series and the temperature of the EGR gas 30 at the outlet of the EGR cooler 15, there is a relationship there, since the number of N steps at which the endoergic side of the heat exchangers 16A connected in series increases, the cooling capacity improves while the temperature of the EGR gas 30 at the outlet of the EGR cooler 15 becomes lower. Thus, although Fig. 10B shows the case where the endoergic sides of the heat exchangers 16A are connected in series in two steps, the temperature of the EGR gases 30 can thus be further lowered by increasing the number of steps of the endoergic side of the heat exchanger 16A in series of three steps or over, in other words, multiple steps.
The above relationship is feasible even in the case where the plurality of EGR coolers 15, each formed by a single integrated unit, are connected in series along the EGR passage 4, while the endoergic side of the heat exchangers 16A, 16A, are connected in series shown in Fig. 10B, or even in the case where the partition 16B is arranged in the EGR cooler 15 is formed by a single integrated unit while the endoergic side of the heat exchangers 16A, 16A, are connected in series as shown in Fig. 8C . In other words, in the configuration shown in Fig. 8C, the cooling capacity can be improved when the number of steps N of the endoergic side of the heat exchangers 16A in series connection increases by increasing the number of partitions 16B. This allows further reduction of the outlet temperature of the EGR gases 30.
It should be noted that in the above embodiments, the EGR cooler 15, which has a configuration in which the exoergic side of the heat exchanger 17 is located higher than the endoergic side of the heat exchanger 16, has been described by way of example. However, since the present invention uses self-generating vibration to circulate the refrigerant 20, the exoergic side of the heat exchanger 17 need not be placed in a higher position than the endoergic side of the heat exchanger 16. As shown in Fig. 11, it may be possible, for example, to to form the EGR cooler 15 in a configuration in which a part of the exoergic side of the heat exchanger 17 is placed in a lower position than the endoergic side of the heat exchanger 16.
Fig. 9 shows an example of arrangement of the EGR cooler 15 shown in ﬁ g. In Fig. 9, the EGR cooler shown in Fig. 8 is located above the engine. Components which have identical features to the components forming the engine 1 and which are additional units, as shown in Fig. 3, are denoted by identical reference numerals.
In the case where the EGR cooler is located above the engine 1, as described above, the EGR cooler 15 is located in the vicinity of the existing EGR passage 4 as a comparison with the case where the EGR cooler 15 is located in front of or behind the radiator 8, shown in the embodiment shown in ﬁ g. 7A and 7B. Thus, the EGR cooler 15 can be arranged without significant modification, such as extension of the pipes from the existing EGR passage 4. For example, the system can be formed only by providing the existing EGR passage above the engine 1 with a screwed-on EGR cooler 15 from another device.

权利要求:
Claims (10)
[1]
A cooling device (15) for a fluid (30), which fluid is EGR gas (30), compressed intake air or engine oil in an internal combustion engine (1), comprising: - a heat exchanger (16) on an endoergic side having a fluid passage (4) for passing the fluid (30) to be cooled and storing a cooling medium (20, 20G) for cooling the fluid (30) by heat exchange with the fluid (30) in the fluid passage Qe ﬂ (4); - a heat exchanger (17) on an exoergic side which is connected to an upper part of the heat exchanger (16) on the endoergic side and allows the refrigerant (20, 20G) coming in from the heat exchanger (16) on the endoergic side to pass through the heat exchanger (17) on the exoergic side; characterized by - cooling means (9; 24) adapted to generate cooling air (21) which cools the coolant (20, 20G) passing through the heat exchanger (17) on the exoergic side by heat exchange with the coolant (20, 20G), and by - the heat exchanger (17) on the exoergic side has at least two refrigerant passages (19), one end of the at least two refrigerant passages (19) being connected to the heat exchanger (16) on the endoergic side and the other ends of the at least two refrigerant passages (19 ) are connected to each other by means of a common coolant passage (19a), - during the operation of the cooling device (15) the cooling medium (20, 20G) which is stored in the heat exchanger on the endoergic side (16) and which is present in both the vapor phase (20G) as liquid phase also fills the refrigerant passages (19) arranged in the heat exchanger on the exoergic side (17), and when refrigerant vapor (20G) flows from the upper part of the heat exchanger on the endoergic side (16) into a refrigerant passage (19) (20, 20G) in an ann a coolant passage (19) into the heat exchanger on the endoergic side (16), - the cooling device (15) being configured to circulate the coolant (20, 20G) between the heat exchanger (16) on the endoergic side and the heat exchanger (17) on the exoergic side through the refrigerant passages (19) due to a local pressure difference between: pressure increase in the heat exchanger (16) on the endurgical side caused by random phase conversion to refrigerant vapor (20G) as a result of absorption of heat by the fluid (30) passing through the heat exchanger (16) on the endoergic side, after which this steam accumulates in the upper part of the heat exchanger (16) on the endoergic side; and decrease in pressure in the refrigerant passages (19) in the heat exchanger (17) on the exoergic side caused by a volume reduction of the refrigerant (20, 2OG) which occurs as a result of condensation of refrigerant vapor (2OG) to the liquid phase when heating absorbed by the cooling air (21) generated by the cooling means (9; 24), - the cooling medium passages (19) have a passage diameter or an equivalent diameter ranging from 2 mm to 16 mm, and - all cooling medium passages (19) are formed with substantially the same diameter or the equivalent diameter.
[2]
The ﬂuid cooling device according to claim 1, comprising an EGR passage (4) for introducing the EGR gas (30) into the cooling device, the fluid to be cooled being exhaust gases (30) passing through the EGR passage (4).
[3]
The fluid cooling device according to claim 1, comprising an engine inlet passage (3) for introducing compressed inlet air into the cooling device, wherein the ﬂ to be cooled is compressed intake air.
[4]
A fluid cooling device according to any one of claims 1 to 3, wherein the cooling means is a cooling fan (9, 24).
[5]
A fluid cooling device according to claim 4, wherein the cooling means is a radiator cooling fan (9) for cooling a radiator (8) through which an engine cooling medium passes.
[6]
The fluid cooling device according to claim 1, wherein a volume ratio of the refrigerant (20, 2OG) to a total volume of the heat exchanger (16) on the endoergic side and the heat exchanger (17) on the exoergic side is set to a predetermined volume ratio which ranges from 20% to 80%.
[7]
The fluid cooling device of claim 1, wherein the cooling device comprises: a plurality of separate heat exchangers (16A) on the endoergic side with fluid passages (4C); 533 908 a plurality of separate heat exchangers (17A) on the exoergic side, each corresponding to a plurality of separate heat exchangers (16A) on the endoergic side, and wherein the fluid passages (4C) in the plurality of separate heat exchangers ( 16A) on the endoergic side are connected in series and said fluid passages (4C) constitute the outlet passage (4) in claim 1, and the cooling device is designed so that a boiling point (T2) of the coolant (20, 20G) in a separate downstream heat exchanger (16A) on the endoergic side is lower than the boiling point (T1) of the refrigerant (20, 20G) in another separate upstream heat exchanger (16A) on the endoergic side in the fluid passage (4).
[8]
The fluid cooling device of claim 7, wherein each of the plurality of separated heat exchangers (16A) on the endoergic side is divided by a partition (16B) that allows the fluid (30) to be cooled to pass to an adjacent heat exchanger (16A). ) on the endoergic side but does not allow the refrigerant (20) to pass to the adjacent heat exchanger (16A) on the endoergic side.
[9]
The fluid cooling device according to claim 4, wherein the heat exchanger (17) on the exoergic side and the heat exchanger (16) on the endoergic side are formed in an annular shape, and the cooling fan (24), which is formed in an annular shape, is arranged as cooling means inside the heat exchanger (17) on the exoergic side.
[10]
Use of a fluid cooling device according to claim 9, wherein the cooling device is located above an internal combustion engine (1).

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同族专利:

公开号 | 公开日

JPWO2007086418A1|2009-06-18|

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DE112007000222T5|2008-11-06|

SE0801726L|2008-09-02|

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法律状态:
2013-09-03| NUG| Patent has lapsed|

优先权:

申请号 | 申请日 | 专利标题

JP2006017704|2006-01-26|

PCT/JP2007/051075|WO2007086418A1|2006-01-26|2007-01-24|Cooling apparatus of liquid|

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