Internal-combustion engines – Cooling – Devices for cooling liquid by air flow
Reexamination Certificate
1999-11-01
2001-03-06
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Cooling
Devices for cooling liquid by air flow
Reexamination Certificate
active
06196169
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a cooling apparatus for the internal combustion engine of a motor vehicle, comprising a cooling-air fan, a radiator assembly and a fan shroud which extends from a fan ring, enclosing the cooling-air fan, as far as the radiator assembly, the radiator assembly projecting laterally beyond the projection of the cooling-air fan, and the projection of the cooling-air fan projecting upward and/or downward beyond the radiator assembly.
Such a cooling apparatus is described, for example, in DE-A 24 39 033 or also in DE-A 34 04 887. As is customary in vehicles with a longitudinally installed engine, the fan is driven by the latter via a V-belt. It covers over a circular surface, of which the vertical position, on account of the drive, is usually unfavorable and can only be selected within narrow limits. For aerodynamic reasons, it is desirable in modern vehicles to have a bonnet which slopes away sharply. In the case of a certain necessary cooling surface, this necessitates a very wide and low radiator assembly.
The radiator assembly projects beyond the projection of the circular surface of the fan at least on one side (in the case of an asymmetrical arrangement), but usually on both sides, and the circular surface, for its part, projects beyond the top edge of the radiator assembly. The fan shroud has to overcome this unfavorable offset flow, which is barely possible on account of the small axial spacing. This results in regions of the radiator assembly which have insufficient flow passing through them, if any at all, and sectors on the cooling-air fan which receive insufficient flow. These regions and sectors can be seen in DE-A 24 39 033.
The consequence is that the cooling system, in certain critical situations (at a standstill in hot climates, where possible still with the air-conditioning system switched on, traveling on inclines under full load, etc.), fails or has to be safeguarded by complex and costly additional precautionary measures (over-dimensioned parts, additional electric fan, temperature-controlled switch-off of additional heat sources, etc.).
The object of the present invention is to improve a cooling apparatus such that, with given dimensioning of the radiator assembly and cooling-air fan, the cooling capacity is increased, with a minimum of structural outlay. Retrofitting in existing vehicles is to be possible.
SUMMARY OF THE INVENTION
The foregoing object is achieved according to the invention wherein the fan shroud forms, in the part which projects laterally beyond the projection of the cooling-air fan, a vertical flow duct with a cross section which increases in the vertical flow direction and, in the part which projects beyond the projection of the radiator assembly, a collecting chamber, the vertical flow duct merging into the collecting chamber and the collecting chamber being open toward that part of the cooling-air fan which projects beyond the projection of the radiator assembly.
In this way, the regions of the radiator assembly which in accordance with the prior art do not have flow passing through them are in connection, via the vertical flow duct and the collecting chamber, with that sector of the cooling-air fan which receives insufficient flow. Both surfaces are utilized. As a result, merely by using the fan shroud configured according to the invention, the cooling capacity was increased by 8%, in the case of simulated traveling on inclines with a maximum road-train weight, and even by 25%, in the case of idling at a standstill.
Depending on the spatial arrangement of the cooling-air fan and radiator assembly, such a vertical flow duct is provided on both sides or just on one side of the fan ring. The collecting chamber is usually formed above the radiator assembly, but, depending on the arrangement, it may also be formed beneath the radiator assembly or above and beneath.
In a development of the idea of the invention, the collecting chamber may grip over the radiator assembly in the direction oriented away from the cooling-air fan and the vertical flow duct may grip around the fan ring on the outside. This means that, without the installation dimensions being increased, large cross sections of the vertical flow duct and of the collecting chamber can be achieved and the fan shroud may be in a form which is particularly practical in production terms. The bonnet may then be of particularly shallow design.
With a virtually symmetrical arrangement of the radiator assembly and cooling-air fan, a vertical flow duct is arranged on both sides of the fan shroud.
For an optimum development of the invention, the flow cross section of the vertical flow duct is selected such that it increases to the same extent as the covered-over radiator surface. This means that the flow speeds in the duct remain more or less equal, with the result that flow losses are kept to a minimum.
REFERENCES:
patent: 5410992 (1995-05-01), Hunt et al.
Bachman & LaPointe P.C.
Harris Katrina B.
Steyr-Daimler-Puch Fahrzeugtechnik AG & Co. KG
Wolfe Willis R.
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