Most vehicles generally in use today, such as passenger cars and motor trucks, are propelled by internal combustion engines and such engines, as is well known, generate heat during the operation thereof. For the most part, the motor vehicle internal combustion engines employed are of the liquid-cooled type which entail the circulation, under pressure, of a coolant through the engine for absorbing heat. The correct operating temperature of the engine is maintained by subsequently and sequentially passing, under pressure, the heated coolant received from the engine through a heat exchange system or apparatus for dissipating heat from the coolant to the atmosphere and returning the coolant to the engine for recirculation therein. Generally, the heat exchange apparatus employed includes a heat exchanger or radiator through which the heated coolant received from the engine is caused to flow. Simultaneously, cooling air is also caused to flow through the radiator which absorbs heat from the heated coolant and carries it out into the atmosphere.
The cooling capacity of a heat exchange apparatus is dependent upon many factors including the velocity and volume of the air caused to flow through radiator core as well as the distribution pattern of the air stream over the available heat exchange surface of the radiator core. Ideally, to achieve the highest heat transfer efficiency of any heat exchange apparatus, it is desirable that the velocity of cooling air flowing through the radiator core be as high as possible and be uniformly distributed over the entire available heat exchange surface of the radiator core. The heat exchange apparatus almost universally found in conventional motor vehicles propelled by liquid-cooled internal combustion engines involves a radiator or heat exchanger assembly which has a flat, generally rectangularly-shaped core structure. The radiator is usually oriented so as to be generally upright and is positioned axially forwardly of the engine. The heat exchange apparatus of conventional motor vehicles also includes, for the most part, a rotary fan of the axial flow, suction type which is positioned intermediate the engine and the flat radiator. The fan is designed to suck or draw air from the atmosphere forwardly of the radiator structure and cause the air stream induced thereby to flow substantially axially through the radiator. Heretofore, in most motor vehicle installations, the air stream after passing through the radiator core was discharged back over the engine which, as pointed out hereinbefore, is usually spaced axially rearwardly of the fan and radiator structure.
The rotary fan used in most motor vehicle engine heat exchange apparatuses for propelling the cooling air through the radiator core includes a multi-bladed rotor. The fan impeller blades extend radially from the fan hub and thus the fan blade tips circumscribe a circle when the fan is being operated.
Automotive cooling system engineers have long been intrigued with the possibility of overcoming the aforementioned operational shortcomings as well as other inherent and well known heat transfer deficiencies of traditional automotive heat exchange systems by using a toroidal type heat exchanger in lieu of the conventional flat radiator. In a toroidal heat exchanger, the radiator core is, in effect, wrapped around the fan and resembles a drum shell with the air stream intake and discharge faces of the radiator core in the form of radially spaced and parallel concentric cylinders. The fan, which is encircled by the radiator core, may be a blower type wherein cooling air is drawn axially from one axial side of the fan impeller blades and discharge radially outwardly through the radiator core or, alternatively, the fan may be a suction type wherein cooling air is drawn radially inwardly through the toroidal radiator core and discharged axially from one axial side of the heat exchange apparatus.
In the past various patents have issued relating to such heat exchange apparatus. For example, U.S. Pat. No. 4,306,614, issued on Dec. 22, 1981 to M. A. Maggiorana, describes a heat exchanger for marine propulsion engines. The heat exchanger includes a closed spiral passageway for the fresh cooling water drawn from the lake. An outer housing encloses the spiral passageway and includes baffle means for directing of a coolant in a spiral path over the cooling passageway within the housing. The coolant is thereby cooled by the circulating cold fresh water.
U.S. Pat. No. 4,895,203, issued on Jan. 23, 1990 to K. S. McLaren, describes a heat exchanger with a helically coiled conduit. The heat exchanger has a hollow cylinder having a cylindrical wall to define an annular space therebetween. A neatly fitting helical tubular coil with spaced helixes define a helical pathway between adjacent coil helixes. Working fluid passes through the tubular coil and process fluid passes through the helical pathway to effect heat exchange between the working and process fluids.
U.S. Pat. No. 4,690,210, issued on Sep. 1, 1987 to Niggemann et at., describes a fluid jet impingement heat exchanger. A mixed phase inlet stream is partially separated by centrifugal forces imparted to the stream by swirl inducers as the stream enters the inlet of the heat exchanger. Heat transfer efficiency is maximized by making the tube of rectangular cross section and providing liquid impingement jets active on three sides of the tube and by providing a baffle which forces the heat transfer fluid to further cool the tube by convection on the remaining side thereof.
U.S. Pat. No. 5,287,917, issued on Feb. 22, 1994 to A. Cannata, describes a heat exchanger having a core comprising a conduit, a plurality of heat conducting elements extending transversely through the conduit and having portions projecting outwardly on each side of the conduit, a plurality of fins spaced along the length of these portions, and a housing enclosing the conduits and heat conducting elements. A means is provided for directing a medium to be heated or cooled through the conduit. A means is also provided for inducing a flow of heat exchanging medium through the housing and over the heat conducting elements and fins.
U.S. Pat. No. 5,343,936, issued on Sep. 6, 1994 to Beatenbough et al., describes a spiral ripple circumferential flow heat exchanger that includes generally parallel plates connected to define a hollow passageway so that a generally circumferential flow of fluid between an inlet and an outlet is achieved. The plates are undulating in cross-section to define obliquely disposed crossing opposing valleys arranged in a spiral disposition.
U.S. Pat. No. 5,445,218, issued on Aug. 29, 1995 to S. Nieh, shows a compact heat exchanger having an annular body with a central cylindrical volume and having an inlet for one fluid at opposite ends. A plurality of peripherally-located first fluid inlets communicate with first fluid passages in the body. These passages curve arcuately outwardly to respective separate outlets on the exterior wall of the body. Another set of passages for another fluid extend axially from one end of the body to the opposite end between oppositely located plenum chambers.
U.S. Pat. No. 6,330,910, issued on Dec. 18, 2001 to E. Bennett, describes a heat exchanger for a motor vehicle exhaust. This heat exchanger has a tubular body with at least two flow passages that extend between the ends of the tubular body. The passages include at least one heat exchange fluid flow passage and at least one bypass fluid flow passage. A heat exchange coil is positioned in the at least one flow passage. The heat exchange coil has an inlet and an outlet that extend through the sidewalls of the tubular body.
U.S. Pat. No. 4,062,401, issued on Dec. 13, 1977 to Rudny et al., provides a toroidal multifluid segmented heat exchanger in which a plurality of segmented components are arranged to form a fixed radial heat exchanger. Each segment is an independent heat exchanger having a core of fluid tubes and air flow corridors between the tubes. Air flow is maintained through the heat exchanger by means of a propeller-type fan mounted coaxially with the heat exchanger.
U.S. Pat. No. 4,066,047, issued on Jan. 3, 19178 to Vidakovic et al., shows another type of toroidal heat exchanger that incorporates an air flow directing support cone housing a hydraulic motor used for driving an air propelling means at variable speeds depending on the cooling requirements of the host vehicle.
U.S. Pat. No. 4,136,735, issued on Jan. 30, 1979 to Beck et al., teaches a heat exchange apparatus including a toroidal-type radiator having radially extending cooling air passage-ways formed through the core thereof, a rotary fan positioned radially inwardly of the radiator core, and fan shroud means shaped and positioned with respect to the radiator core and the blades of the fan whereby the air stream induced by the fan during operation has a major component in a radial direction.
It is an object of the present invention to provide a heat exchanger which efficiently exchanges heat with air passing therethrough.
It is another object of the present invention to provide a heat exchange whereby a toroidal flow of a coolant will extend around an air flow conduit.
It is still another object of the present invention to provide heat exchanger whereby separate flows of air are provided through the heat exchanger for the purposes of cooling the coolant and for drawing air to the engine of a vehicle.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.