Heat exchange – Three non-communicating fluids
Reexamination Certificate
2000-01-21
2001-04-03
Leo, Leonard (Department: 3743)
Heat exchange
Three non-communicating fluids
C165S135000, C165S146000
Reexamination Certificate
active
06209628
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat exchanger in which different core portions are integrated with each other, and more particularly the present invention relates to a heat exchanger which can be effectively applied to a radiator of an automotive engine and a condenser of an automotive air conditioning apparatus.
2. Description of Related Art
Conventionally, an automotive air conditioning apparatus is assembled into a vehicle at a car dealer or the like after the vehicle has been completed. Recently, however, the automotive air conditioning apparatus is generally installed in the vehicle during vehicle assembling process. Therefore the automotive air conditioning apparatus is assembled with automotive parts in the assembling process of the vehicle at the manufacturing plant.
A heat exchanger in which different core portions such as a radiator and a condenser are integrated is disclosed in Japanese Patent Publication No. 3-177795. In this heat exchanger, cooling fins of first core portion and second core portion are integrated with each other. These cooling fins are connected to each oval flat tube of the first and second core portions by brazing.
In the cooling fin, a plurality of slits are formed at the center portion between the first and second core portions for interrupting a heat transmission from a high temperature side core portion (for example, radiator core portion) to a low temperature side core portion (for example, condenser core portion).
The required heat exchanging abilities of the first core portion (condenser core portion) and the second core portion (radiator core portion) varies in accordance with the difference of engine type or vehicle type despite the required constitutions of the heat exchanger are the same. When the automotive heat exchanger is constructed by some single heat exchangers, the required heat exchanging abilities thereof are set by tuning fin pitches of the cooling fins respectively in accordance with the engine type or vehicle type.
However, in the heat exchanger in which different core portions are integrated and cooling fins of first core portion and second core portion are integrated with each other, each fin pitch cannot be designed independently respectively. Therefore, the above-described method of setting the fin pitches in the first and second core potions respectively cannot be applied to this type heat exchanger.
SUMMARY OF THE INVENTION
In view of the foregoing problems, it is an object of the present invention to provide a heat exchanger in which different core portions and cooling fins thereof are integrated with each other, while setting the required heat exchanging abilities of each core portion independently respectively.
According to a first aspect of the present invention, a ratio, in a first core portion, of the number of louvers to a width of a first cooling fin, and a ratio, in a second core portion, of the number of louvers to a width of a second cooling fin are set to be in such a manner that the ratio in one core portion, out of said first and second core portion, the required radiation amount of which is larger than that of the other core portion is larger than the ratio in the other core portion.
Thus, in the core portion having a small required radiation amount, the number of louvers relative to the width of the cooling fin is small thereby decreasing the heat transfer ratio. However, the pressure loss in this core portion decreases thereby increasing the amount of an external fluid. Thus, the radiation amount of the core portion having a large required radiation amount increases.
According to a second aspect of the present invention, in one core portion, out of the first and second core portions, the required radiation amount of which is smaller than that of the other core portion, a width of the cooling fin in an external fluid flow direction is shorter than a width of a tube in its cross sectionally longitudinal direction. Further, a ratio, in the first core portion, of the number of louvers to the width of a first tube, and a ratio, in the second core portion, of the number louvers to the width of a second tube are set to be in such a manner that the ratio in one core portion, out of the first and second core portions, the required radiation amount of which is smaller than that of the other core portion is smaller than the ratio in the other core portion.
Thus, in the core portion having a small required radiation amount, the width of the cooling fin and the number of louvers relative to the width of the tube in its cross sectionally longitudinal direction are small thereby decreasing the heat transfer ratio. However, by this, the pressure loss in the core portion decreases thereby increasing the amount of an external fluid. Thus, the radiation amount of the core portion having a large required radiation amount increases.
According to a third aspect of the present invention, the length of the louver in one core portion, out of the first and second core portions, the required radiation amount of which is smaller than that of the other core portion is shorter than the length of the louver in the other core portion.
Thus, in the core portion having a small required radiation amount, the length of the louver is short thereby decreasing the heat transfer ratio. However, by this, the pressure loss in the core portion decreases thereby increasing the flow amount of the external fluid. Thus, the radiation amount of the core portion having a large required radiation amount increases.
According to a fourth aspect of the present invention, a tilt angle of the louver in one core portion, out of the first and second core portion, the required radiation amount of which is smaller than that of the other core portion is smaller than the tilt angle of the louver in the other core portion.
Thus, in the core portion having a small required radiation amount, the tilt angle of the louver is small thereby decreasing the heat transfer ratio. However, by this, the pressure loss in the core portion decreases thereby increasing the flow amount of the external fluid. Thus, the radiation amount of the core portion having a large required radiation amount increases.
REFERENCES:
patent: 4693307 (1987-09-01), Scarselletta
patent: 5033540 (1991-07-01), Tategami et al.
patent: 5311935 (1994-05-01), Yamamoto et al.
patent: 5720341 (1998-02-01), Watanabe et al.
patent: 61-59195 (1986-03-01), None
patent: 6-221787 (1994-08-01), None
Sakane Takaaki
Sugimoto Tatsuo
Suzuki Shinobu
Yamanaka Yasutoshi
Denso Corporation
Harness Dickey & Pierce PLC
Leo Leonard
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