Most of the automobiles that are in use today have the engine bay located at the front of the vehicle. Typically an internal structural cross-member bridges the front of the bay and supports a radiator that is a part of the engine's cooling system. When the vehicle is equipped with air conditioning, a condenser mounts in front of the radiator. The radiator and condenser are cooled by air that passes through them, the air either being forced through the radiator and condenser by ram air effect when the vehicle is in forward motion, and/or by being drawn through the radiator and condenser by a fan or fans located directly behind the radiator and condenser. As a result, the engine bay is ventilated by air that has been heated by the radiator and condenser. Before this air leaves the engine bay, it is further heated by the heat emitted directly by the engine. Consequently, elevated temperatures can occur in the engine bay and at other locations that are exposed to heated air from the engine bay. These elevated temperatures may be sufficiently high to create thermally induced problems in certain areas or components of an automotive vehicle.
Commonly assigned, allowed U.S. patent application Ser. No. 07/357,509, filed May 25, 1989, now U.S. Pat. No. 4,979,584, in the name of Herbert N. Charles, discloses a new and unique arrangement for ventilating an engine bay to reduce temperatures. The invention of that patent application involves the use of a ducted fan system to draw cooling air through the radiator and condenser and to convey the hot effluent from the radiator and condenser through a conduit that empties to a location that is outside the engine bay so that the engine bay is not ventilated by the hot effluent. Apertures are provided in the structural cross-member that supports the radiator/condenser heat exchange structure so that the engine bay can be ventilated by ambient ram air when the vehicle is in forward motion. Accordingly, an arrangement of that type provides a means for obtaining significant temperature reductions in the engine bay in comparison to conventional installations where the engine bay is ventilated by hot effluent from radiator/condenser heat exchange structure.
It has now been discovered that a ducted fan system like that just described can be used to further enhance the ventilation of the engine bay by the incorporation of an ejector into the ducted fan system at a location downstream of the fan. The effluent from the radiator/condenser heat exchange structure is conducted through the ejector, and the ejector is effective, under certain conditions of operation of the ducted fan, to cause the effluent that passes through the ejector to create a relatively lower pressure zone where the pressure is less than that of a relatively higher pressure zone of the engine bay or of a location adjacent the engine bay that is exposed to heat from the engine bay. The relatively lower pressure zone of the ejector is placed in communication with the relatively higher pressure zone of the engine bay, or adjacent location, for example by means of a ventilating conduit that extends from the relatively higher pressure zone of the engine bay or adjacent location and tees into the ducted fan system at the relatively lower pressure zone of the ejector. As a result, a flow is induced in the ventilating conduit, and that flow draws air from the relatively higher pressure zone of the engine bay or adjacent location into the ejector where the flow entrains with the effluent passing through the ducted fan system to be ultimately discharged from the ducted air system along with the effluent to a location outside the engine bay where the discharge of the effluent is acceptable. It is contemplated that a suitably designed ejector and ventilating conduit can induce in the ventilating conduit flows of as much as about 10% to 15% of the effluent flow without appreciable loss of efficiency in the operation of the ducted fan system. Consequently, the invention now makes it possible to enhance the ventilation of the engine bay, and especially to enhance the ventilation of hot spots in the engine bay or adjacent locations that are exposed to heat from the engine bay.
Certain components of an automobile that are typically within the engine compartment, fuel lines and batteries for instance, may be located where there is insufficient ventilation to provide acceptable cooling for these components. If such is the case, the present invention can provide a very effective solution which comprises designing an ejector into the ducted fan system, and running a ventilating conduit from the hot spot to the ejector. The solution is especially advantageous because the ejector and the ventilating conduit contain no moving parts. The ejector can be fabricated by conventional plastic molding techniques, and the ventilating conduit can be fabricated in any of a number of conventional ways, such as using flexible or rigid hose or tubing. One of the disclosed embodiments of the invention contemplates an especially efficient use of both materials and available space within the engine bay by integrating the ejector with the ducted fan scroll.
The foregoing features, advantages and benefits of the invention, along with additional ones, will appear in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.