1. Field of the Invention
This invention relates to an automatic transmission fluid cooling system for internal combustion engines used in trucks and other motor vehicles and, in particular, to a cooling system utilizing a concentric tube oil cooler in combination with a radiator.
2. Description of Related Art
Radiators for automobiles have evolved in recent years from soldered units made of copper and brass to mechanically assembled units having brazed aluminum cores and plastic tanks. Common to the two types of radiators has been an oil cooler installed in the outlet radiator tank for the purpose of cooling automatic transmission fluid by the engine coolant. Occasionally, automobile or light truck radiators are made with a transmission oil cooler in one radiator tank and an engine oil cooler of similar construction in the other tank. Such oil coolers have typically been either of the concentric tube type or of the stacked plate type. The stacked plate type oil cooler is typically higher cost, usually being made of stainless steel, and has higher performance than the concentric tube type oil cooler of similar size. The concentric tube type oil cooler typically consists of two concentric brass tubes welded together at their ends and has a lanced-offset inner fin between them for turbulation of the transmission fluid or oil.
While motor vehicle radiator design changes in recent years have resulted in lower cost and better-controlled product quality, e.g., by the use of brazed aluminum which allows the use of more highly automated and more consistent manufacturing processes, the oil cooler remains the single most expensive component of a radiator. There is a great need, both for original equipment and aftermarket radiators, to reduce the cost and improve the performance of this component, the design and installation of which has remained unchanged for many years.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide an improved system and method for cooling a concentric oil cooler in a motor vehicle radiator tank.
It is another object of the present invention to provide a baffle for a concentric oil cooler in a radiator tank that improves circulation of coolant in the tank to cool the oil flowing through the oil cooler.
A further object of the present invention is to provide an improved baffle and concentric oil cooler combination that may be easily assembled in a radiator tank and that provides cost savings in manufacture.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The above and other objects, which will be apparent to those skilled in the art, are achieved in the present invention which is directed to a radiator and oil cooler combination for an internal combustion engine comprising a radiator core comprising a plurality of tubes and fins between the tubes, an inlet radiator tank and an outlet radiator tank. The inlet radiator tank has an engine coolant inlet and is connected along a side of the tank to the tubes at one end of the radiator core, so as to permit coolant flow entering from the coolant inlet to pass into the radiator core tubes. The outlet radiator tank has an engine coolant outlet and is connected along a side thereof to the tubes at the other end of the radiator core, with openings of the tubes extending along a length of the outlet radiator tank side. The outlet radiator tank permits coolant flow entering from the radiator core tubes to pass through the coolant outlet. The invention also includes an oil cooler within the outlet radiator tank comprising inner and outer concentric tubes sealed to each other at opposite ends thereof. Fluid connections through the outer concentric tube allow oil to enter and exit the oil cooler. The oil may flow in the oil cooler between the inner and outer tubes, and the coolant may flow along an outer wall of the outer tube and through the inside of the inner concentric tube along an inner wall thereof. The invention also includes a baffle between an inner surface of the outlet radiator tank housing and the outer wall of the oil cooler forming a barrier substantially filling the space therebetween. The baffle is located away from the ends of the oil cooler, intermediate the length thereof, and intermediate the length of the outlet radiator tank containing the tube openings.
In the method of use of the invention, oil is flowed through the oil cooler and engine coolant is flowed from the inlet radiator tank in a single pass through the tubes of the radiator core to the outlet radiator tank. Coolant entering from the radiator core tubes on one side of the baffle is directed along the oil cooler outer wall in a direction away from the baffle and then entirely through the inside of the inner concentric tube along the inner wall thereof and out the outlet radiator tank outlet. Coolant entering from the radiator core tubes on the other side of the baffle is directed along the oil cooler outer wall in a direction away from the baffle and out the outlet radiator tank outlet, without passing through the inside of the inner concentric tube, to cool the oil flowing through the oil cooler.
The baffle may have first and second portions substantially sealing with each other, whereby the sealed portions form a substantially flat perpendicular barrier filling the space between the inner surface of the tank housing and the outer surface of the oil cooler. One of the baffle portions may be integral with the tank housing. One of the baffle portions may have a slot to engage an edge of the other of the baffle portions.
The baffle may comprise a resilient, single piece having an opening for the oil cooler and a slit between the opening and an outer edge of the piece to enable the baffle to be positioned around the oil cooler. The radiator and oil cooler combination may further include a baffle reinforcement member engageable with the baffle over the slit to reinforce the baffle.
In a modification of the invention, the oil cooler and baffle may be placed in the inlet tank in a position similar to that described for the outlet tank. In such case, a portion of coolant entering from the inlet radiator tank coolant inlet is directed through the inside of the inner concentric tube along the inner wall thereof and then along the oil cooler outer wall and out the radiator core tubes on one side of the baffle, and another portion of coolant entering from the inlet radiator tank coolant inlet is directed along the oil cooler outer wall and out the radiator core tubes on the other side of the baffle, without passing through the inside of the inner concentric tube.
In another aspect, the present invention is directed to a radiator and oil cooler combination for an internal combustion engine comprising a radiator tank having an engine coolant outlet, with the radiator tank being connected along a side thereof to radiator core tubes. Openings of the tubes extend along a length of the outlet radiator tank side, so that the radiator tank permits coolant flow entering from the radiator core tubes to pass through the coolant outlet. This aspect of the invention also includes an oil cooler within the radiator tank comprising inner and outer concentric tubes sealed to each other at opposite ends thereof, with fluid connections through the outer concentric tube to allow oil to enter and exit the oil cooler. The oil may flow in the oil cooler between the inner and outer tubes, and the coolant may flow along an outer wall of the outer tube and through the inside of the inner concentric tube along an inner wall thereof. The invention also includes a baffle between and spaced from the oil cooler and the radiator core tube openings. The baffle extends along at least a portion of the length of the outlet radiator tank containing the tube openings and overlaps at least a portion of the length of the oil cooler.
In the method of use of the invention, oil is flowed through the oil cooler and engine coolant is flowed from the radiator core tubes to the radiator tank, whereby the baffle directs substantially all of the coolant entering from the core tubes toward one end of the radiator tank and then directs a portion of the coolant through the inside of the inner concentric tube along the inner wall thereof and another portion of the coolant along the oil cooler outer wall, to cool the oil flowing through the oil cooler.
In a modification of this aspect of the invention, the oil cooler and baffle may be placed in the inlet tank in a position similar to that described for the outlet tank. In such case, the baffle directs substantially all of the coolant entering from the radiator tank engine coolant inlet toward one end of the radiator tank such that a portion of the coolant is directed through the inside of the inner concentric tube along the inner wall thereof and another portion of the coolant is directed along the oil cooler outer wall.
In another aspect, the present invention is directed to a radiator and oil cooler combination for an internal combustion engine comprising a radiator tank having an engine coolant outlet, with the radiator tank being connected along a side thereof to radiator core tubes. Openings of the tubes extend along a length of the outlet radiator tank side, so that the radiator tank permits coolant flow entering from the radiator core tubes to pass through the coolant outlet. The invention includes an oil cooler within the radiator tank comprising inner and outer concentric tubes sealed to each other at opposite ends thereof, with fluid connections through the outer concentric tube to allow oil to enter and exit the oil cooler. The oil may flow in the oil cooler between the inner and outer tubes, and the coolant may flow along an outer wall of the outer tube and through the inside of the inner concentric tube along an inner wall thereof. This aspect of the invention also includes a baffle located in the radiator tank near one end of the oil cooler. The baffle has an opening spaced from the oil cooler outer wall.
In the method of use of the invention, oil is flowed through the oil cooler and engine coolant is flowed from the radiator core tubes to the radiator tank, whereby the spacing between the baffle opening and the outer wall restricts coolant flow therethrough so as to permit a portion of the coolant entering from the radiator core tubes to pass between the oil cooler and the opening and out the coolant outlet while forcing the other portion of the coolant entering from the radiator core tubes to flow away from the baffle opening, along the oil cooler outer wall and through the inside of the inner concentric tube along the inner wall and out the baffle opening and coolant outlet.
The baffle may comprise a plate located beyond the end of the oil cooler, toward the coolant outlet of the tank. The baffle opening may be the same as, smaller than, or larger than a diameter of the oil cooler.
The baffle may comprise a plate located between the ends of the oil cooler, with the baffle opening being larger than a diameter of the oil cooler.
Alternatively, the baffle may comprise a tube extension attached to the tank coolant outlet, with the baffle opening comprising a free end of the tube extension. The baffle opening may be the same as, smaller than, or larger than a diameter of the oil cooler. If larger, the baffle tube extension free end may overlap an end of the oil cooler.
In a modification of this aspect of the invention, the oil cooler and baffle may be placed in the inlet tank in a position similar to that described for the outlet tank. In such case, the spacing between the baffle opening and the outer wall restricts coolant flow therethrough so as to permit a portion of the coolant entering from the radiator tank engine coolant inlet to pass between the oil cooler and the opening, along the oil cooler outer wall and out the radiator core tubes while forcing the other portion of the coolant entering from the radiator tank engine coolant inlet to through the inside of the inner concentric tube along the inner wall and out the radiator core tubes.
The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:
In describing the preferred embodiment of the present invention, reference will be made herein to
The first embodiment of the preferred motor vehicle radiator and oil cooler combination of the present invention, shown in
As shown in the end view of
In the preferred oil cooler configuration of the present invention, oil cooler 16 is located internal to the outlet tank 14 and is positioned so that the longitudinal axis of the oil cooler lies along the length of the tank (i.e., the width of the radiator) and the oil cooler is essentially parallel with proximate to the front wall of the outlet tank (
The oil cooler 16 of the first embodiment shown is held in place by baffle 40, the inlet tube 36 and the outlet tube 38. The oil cooler is located proximate front wall 39a of the outlet tank where the inlet tube and the outlet tube pass through and are externally sealed with the front wall to form a leak-tight seal. Baffle 40 is planar in configuration and is normal to the longitudinal axis of the oil cooler to completely fill and seal the space between the outer surface of the oil cooler and the inner surface of the tank, thereby preventing coolant flow from one end of the tank to the other except through the interior tube of the oil cooler. The baffle is located at a mid-portion of the oil cooler, away from ends 16a, 16b. Baffle 40 is captured and held in place along its entire outer edge by mounting in baffle slot 42 extending around the interior surface of the walls of tank 14. In the case of a plastic tank, the baffle slot may be molded in and integral with the tank itself. In the embodiments shown herein, the baffle may be made of plastic or other suitable material.
Baffle 40 may be constructed and used in several ways. As shown in
In a modification shown in
In operation of the cooling system of
In the first embodiment of the invention shown in
Referring to
In operation, baffle 40d guides substantially the entire flow of coolant 80d in a direction toward the end 16b of the oil cooler opposite the coolant outlet 26. The coolant then flows in the opposite direction, toward outlet 26, and divides between a portion that flows on the outside of the oil cooler along the outer wall 32 and a portion that flows through the interior aperture of the oil cooler along the inner wall 34. The coolant then flows to the coolant outlet 26 and out of the system. Placement of the end 40d′ and oil cooler adjust the flow proportions and allow for maximized heat transfer from the oil cooler to the coolant, and may be determined without undue experimentation.
Referring to
Alternatively, the baffle may have an opening of size greater than the oil cooler outer diameter, and may be located between the ends 16a, 16b of the oil cooler, as shown by baffle 40e′ in phantom lines in
In a further modification of this embodiment of the invention, as shown in
In operation of the embodiment and modifications of
The ratio of the amount of flow in the two coolant portions is determined by the size of the baffle opening 45 and the gap 54. As the baffle opening 45 and/or gap 54 are made larger, less coolant flow will be forced to flow through the interior aperture of the oil cooler. The sizes of baffle opening 45 and gap 54 are chosen to provide an optimum coolant flow through the interior aperture of the oil cooler; that is, a flow rate which will provide sufficient turbulation to provide maximum heat transfer without excessive coolant pressure drop. These sizes may be determined without undue experimentation. If baffle extension 62 (
Thus, the present invention provides a baffle for a concentric oil cooler in a radiator tank that improves circulation of coolant in the tank to cool the oil flowing through the oil cooler. Moreover, the baffle and concentric oil cooler combination of the present invention may be easily assembled in a radiator tank and that provides cost savings in manufacture.
While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. For example, the oil cooler embodiments of the present invention may be disposed in the inlet tank 12 in the same manner as described above in connection with the outlet tank, except that the coolant outlet becomes the coolant inlet, and all of the coolant flows are reversed from the directions described in the specification and shown in the drawing figures. In this modification, the engine coolant used to cool the oil in the oil cooler is hotter than when the oil cooler is disposed in the outlet tank, since it has not yet been cooled by passage through the radiator core. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.
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Number | Date | Country |
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11062587 | Mar 1999 | JP |