WO2020097333A1

WO2020097333A1 - Heat exchanger assembly with single helix liquid-cooled charge air cooler

Info

Publication number: WO2020097333A1
Application number: PCT/US2019/060272
Authority: WO
Inventors: John A. Kolb
Original assignee: Enterex America, Llc
Priority date: 2018-11-07
Filing date: 2019-11-07
Publication date: 2020-05-14

Abstract

A combination radiator and charge air cooler comprises a core for cooling liquid engine coolant, an inlet tank having a first end and a second end and being connected to inlet ends of tubes of the core and having a coolant inlet for receiving the liquid engine coolant, and an outlet tank having first and second ends with a first portion and a second portion between the first and second ends, the first portion being connected to the outlet ends of the core tubes for receiving cooled liquid coolant from the core. The outlet tank has an opening between the first and second portions for passing cooled liquid coolant to the second outlet tank portion, a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine. The outlet tank second portion includes a thermally conductive tube insert sealed therein comprising a single helix extending along a length of the tube insert and twisted around a central axis to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the outlet tank second portion, respectively.

Description

HEAT EXCHANGER ASSEMBLY WITH SINGLE HELIX LIQUID-COOLED CHARGE AIR COOLER

Technical Field The present invention relates to generally to heat exchanger assemblies comprising charge air coolers for cooling fluids used in the engine of a motor vehicle, and more specifically, to an integrated heat exchanger package comprising one or more radiators coupled to a charge air cooler including a helical insert comprising a single helix. Description of Related Art

Heat exchanger packages comprising a radiator and a charge air cooler, also known as an intercooler, have been used for years in over the road highway trucks and buses and other heavy-duty motor vehicles. The radiators provide cooling for the engine coolant, usually a 50-50 solution of water and anti-freeze. The charge air cooler receives ,com pressed, charge or intake air from the turbo- or super-charger and lowers its temperature before it enters the engine intake manifold, thereby making it denser, improving combustion, raising power output and reducing emissions. In order to optimize heat transfer in a given heat exchanger package size, the factors of cooling air flow, heat exchanger core restriction, cooling air flow split and cooling air approach and differential temperature must be balanced.

There is usually limited space availability in the engine compartment for such heat exchanger packages because of sloping hoods covering the engine compartment in the front of trucks, and compact engine compartments in the rear of buses. Both the radiator and the charge air cooler are cooled by the ambient air forced through each by the associated fan and the speed of the vehicle. Because desired cooling capability is continually rising along with the desire for increased engine power and the enactment of new emissions regulations which results in increased heat rejection, enormous demands are placed on the heat exchanger package designer to achieve maximum heat transfer in minimum space. ln an effort to obtain more power from a given engine, modern vehicle and power equipment designers have utilized turbocharging with aftercooling in many applications. In an effort to minimize the space required to provide this added power, designers have, in many cases, opted away from air-to-air charge air cooling in favor of liquid-cooled charge air coolers. Anything that can be done to reduce the overall size of the power package is greatly desired.

Therefore, a need exists for an improved heat exchanger assembly which reduces the overall size of the power package.

Disclosure of the Invention Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a more compact and efficient cooling package for a motor vehicle, which takes up less engine compartment or generator set space.

It is another object of the present invention to provide an improved heat exchange package that combines a charge air cooler having a helical insert with one or more engine cooling radiators in order to reduce the overall size of the cooling package.

A further object of the invention is to provide an improved heat exchange package which utilizes less material and thereby costing significantly less to produce.

It is yet another object of the present invention to provide an improved heat exchange package which utilizes less material and thereby has less overall weight.

Stil l 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 in a first aspect to a combination radiator and charge air cooler for cooling liquid coolant from an engine and for cooling pressurized charge air from the engine. The combination radiator and charge air cooler comprises a core for cooling the liquid engine coolant, the core having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins. An inlet tank has a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, the inlet tank being connected between the first and second ends to the inlet ends of the core tubes for passing liquid coolant through the core to be cooled. An outlet tank has a first end and a second end, and a first portion and a second portion between the first and second ends, the outlet tank first portion being connected between the first and second ends to the outlet ends of the core tubes for receiving cooled liquid coolant from the core. The outlet tank has an opening between the outlet tank first portion and the outlet tank second portion for passing cooled liquid coolant to the second outlet tank portion. The outlet tank second portion has a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving the pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine. The outlet tank second portion has an inner diameter and includes a thermally conductive tube insert having an outer diameter substantially equal to the inner diameter of the second outlet tank portion. The tube insert has first and second ends and comprises a helix extending along a length of the tube insert twisted around a central axis, the tube insert sealed within the outlet tank second portion by sealing an outer edge of the helix to an inner surface of the outlet tank second portion to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the outlet tank second portion, respectively. The tube insert first flow path has an inflow opening in communication with the opening between the outlet tank first and second portions and an outflow opening in communication with the outlet tank second portion liquid coolant outlet such that liquid coolant may flow from the outlet tank first portion through the tube insert first flow path, absorb heat transferred through the thermally conductive tube insert from the charge air in the tube insert second flow path, and pass out the outlet tank second portion coolant outlet back to the engine. The tube insert second flow path has an inflow opening in communication with the outlet tank second portion pressurized charge air inlet and an outflow opening in communication with the outlet tank second portion pressurized charge air outlet, such that pressurized charge air may flow from the outlet tank second portion pressurized charge air inlet through the tube insert second flow path, transfer heat through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and pass out the outlet tank second portion pressurized charge air outlet back to the engine.

In an embodiment, the combination radiator and charge air cooler may further include a common wall separating the outlet tank first and second portions, and the opening between the outlet tank first portion and the outlet tank second portion may be in the common wall. The common wall may further be made of a thermally conductive material to permit heat flow between liquid coolant in the outlet tank first portion and liquid coolant in the tube insert first flow path in the outlet tank second portion, and between liquid coolant in the outlet tank first portion and pressurized charged air in the tube insert second flow path in the outlet tank second portion. The opening in the common wall may be adjacent to the first end of the outlet tank. The outlet tank second portion pressurized charge air outlet may be adjacent the first end of the outlet tank, and the outlet tank second portion pressurized charge air inlet may be adjacent the second end of the outlet tank. The tubes may be vertically arrayed, and the inlet tank may be above the outlet tank. A plurality of the cores may be disposed between the inlet and outlet tanks. The core tubes may further be horizontal ly arrayed, and the inlet and outlet tanks may be vertically arrayed.

In a further embodiment, the combination radiator and charge air cooler core may comprise a first core, and the opening between the outlet tank first portion and the outlet tank second portion may comprise a first opening. The combination radiator and charge air cooler may further include a first wall between the first and second ends of the outlet tank first portion forming separate outlet tank first portion segments, wherein the first core tube outlet ends are connected to the outlet tank first portion segment adjacent the first end such that cooled liquid coolant from the first core may be received into the outlet tank first portion segment adjacent the first end and pass through the first opening between the outlet tank first and second portions. A second core having the tube inlet ends may connect to the inlet tank between the first and second ends for passing liquid coolant through the second core to be cooled, and tube outlet ends may be connected to the outlet tank first portion segment adjacent the second end such that cooled liquid coolant from the second core may be received into the outlet tank first portion segment adjacent the second end. A second opening may be between the outlet tank first portion segment adjacent the second end and the outlet tank second portion, the second opening being in communication with the tube insert first flow path between inflow opening and the outflow opening, such that cooled liquid coolant from the second core may pass through the second opening between the outlet tank first and second portions. Cooled liquid coolant from the first core and cooled liquid coolant from the second core may be combined in the outlet tank second portion in the tube insert first flow path and pass out the outlet tank second portion coolant outlet back to the engine.

In still a further embodiment, the helix may have a predetermined pitch defining a length of the first and second fluid flow paths within the outlet tank second portion, and the pitch of the helix may vary along the length of the tube insert from a minimum adjacent the first end of the outlet tank second portion to a maximum adjacent the second end of the outlet tank second portion.

The combination radiator and charge air cooler may stil l further include a second wall between the first wall and the second ends of the outlet tank first portion, and the first and second walls may form separate outlet tank first portion segments of the outlet tank first portion. A third core may have the tube inlet ends connected to the inlet tank between the first and second cores for passing liquid coolant through the third core to be cooled and tube outlet ends connected to the outlet tank first portion segment between the first and second cores such that cooled liquid coolant from the third core may be received into the outlet tank firs portion segment between the first and second walls. A third opening may be in the outlet tank and between the outlet tank first portion segment between the first and second walls and the outlet tank second portion, the second opening being in communication with the tube insert first flow path between the inflow opening and the outflow opening, such that cooled liquid coolant from the third core may pass through the third opening between the outlet tank first and second portions. Cooled liquid coolant from the first, second and third cores may be combined in the outlet tank second portion in the tube insert first flow path and pass out the outlet tank second portion coolant outlet back to the engine.

In yet another embodiment, the combination radiator and charge air cooler core may comprise a first core and the inlet tank may comprise a first inlet tank, and still further include a second core for cooling the liquid engine coolant, the second core having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins. A second inlet tank may have a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, the second inlet tank being connected between the first and second ends to the inlet sides of the tubes of the second core for passing liquid coolant through the second core to be cooled. The outlet tank may have a third portion between the first and second ends on a side of the outlet tank second portion opposite the outlet tank first portion, the outlet tank being connected to the outlet ends of the tubes of the second core for receiving cooled liquid coolant from the second core, the second inlet tank being disposed on a side of the outlet tank opposite the first inlet tank, and the second core being disposed between the second inlet tank and the outlet tank, the outlet tank third portion being connected between the first and second ends to the outlet ends of the tubes of the second core for receiving cooled liquid coolant from the second core. A second opening may be between the outlet tank third portion and the outlet tank second portion for passing cooled liquid coolant to the second outlet tank portion. The tube insert first flow path inflow opening may be in communication with the second opening between the outlet tank third and second portions such that liquid coolant may flow from the second core through the outlet tank third portion, through the outlet tank having a second opening and through the tube insert first flow path and out the outlet tank second portion coolant outlet back to the engine.

A second thermal ly conductive common wall may separate the outlet tank third and second portions to permit heat flow between liquid coolant in the outlet tank third portion and liquid coolant in the tube insert first flow path in the outlet tank second portion, and between liquid coolant in the outlet tank third portion and pressurized charge air in the tube insert second flow path in the outlet tank second portion, and wherein the second opening between the outlet tank third portion and the outlet tank second portion is in the common wall.

In yet another embodiment, the combination radiator and charge air cooler inlet tank may further comprise a first inlet tank and the first inlet tank and the outlet tank may be vertically arrayed, and include a first plurality of the cores disposed between the first inlet tank and the outlet tank. The combination radiator and charge air cooler may still further include a second plurality of the cores for cooling the liquid engine coolant, the second plurality of the cores having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins. A second inlet tank may have a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, the second inlet tank being connected between the first and second ends to the inlet sides of the tubes of the second plurality of cores for passing liquid coolant through the second core to be cooled. The outlet tank may have a third portion between the first and second ends on a side of the outlet tank second portion opposite the outlet tank first portion, the outlet tank being connected to the outlet ends of the tubes of the second plurality of cores for receiving cooled liquid coolant from the second plurality of cores, the second inlet tank being disposed on a side of the outlet tank opposite the first inlet tank, and the second plurality of cores being disposed between the second inlet tank and the outlet tank, the outlet tank third portion being connected between the first and second ends to the outlet ends of the tubes of the second plurality of cores for receiving cooled liquid coolant from the second plurality of cores. A second opening may be between the outlet tank third portion and the outlet tank second portion for passing cooled liquid coolant to the second outlet tank portion, the tube insert first flow path inflow opening may be in communication with the second opening between the outlet tank third and second portions such that liquid coolant may flow from the second plurality of cores through the outlet tank third portion, through the outlet tank having a second opening and through the tube insert first flow path and out the outlet tank second portion coolant outlet back to the engine.

In still another embodiment, the combination radiator and charge air cooler may further include at least one wall between the first and second ends of the outlet tank first portion forming separate outlet tank first portion segments, wherein the tube outlet ends of each of the first plurality of cores are connected to an associated outlet tank first portion segment that cooled liquid coolant from each of the first plurality of cores may be received into the associated outlet tank first portion segment. At least one wal l may be between the first and second ends of the outlet tank third portion forming separate outlet tank third portion segments, wherein the tube outlet ends of each of the second plurality of cores are connected to an associated outlet tank third portion segment such that cooled liquid coolant from each of the second plurality of cores may be received into the associated outlet tank third portion segment. Openings may be between each of the outlet tank first portion segments and the outlet tank second portion, and between each of the outlet tank third portion segments and the outlet tank second portion, the openings being in communication with the tube insert first flow path between the inflow opening and the outflow opening, such that cooled liquid coolant from the first and second plurality of cores may pass through the openings from the outlet tank first and third portion segments to the outlet tank second portion. Cooled liquid coolant from the first plurality of cores and cooled liquid coolant from the second first plurality of cores may be combined in the outlet tank second portion in the tube insert first flow path and pass out the outlet tank second portion coolant outlet back to the engine. In another embodiment, the combination radiator and charge air cooler helix has a predetermined pitch defining a length of the first and second fluid flow paths within the outlet tank second portion, wherein the pitch of the helix varies along the length of the tube insert from a minimum adjacent the first end of the outlet tank second portion to a maximum adjacent the second end of the outlet tank second portion.

In another aspect, the present invention is directed to a combination radiator and charge air cooler system for cooling liquid coolant from an engine and for cooling pressurized charge air from the engine. It comprises a plurality of cores for cooling the liquid engine coolant, each core having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins. An inlet tank associated with each of the cores has a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, each inlet tank being connected between the first and second ends to the inlet ends of the tubes of the associated core for passing liquid coolant through the associated core to be cooled. An outlet tank associated with each of the cores has a first end and a second end and a coolant outlet, each outlet tank being connected between the first and second ends to the outlet ends of the tubes of the associated core for receiving cooled liquid coolant from the associated core. A helical heat exchanger comprises a tube having first and second ends, a coolant inlet for receiving liquid coolant from the outlet tanks, a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving the pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine. The tube further has an inner diameter and a thermally conductive tube insert having an outer diameter substantially equal to the inner diameter of the tube, the tube insert having first and second ends and comprises a helix extending along the length of the tube insert and twisted around a central axis, the tube insert sealed within the tube by sealing an outer edge of the helix to an inner surface of the tube to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the tube. Each of the tube insert first and second flow path has an inflow opening and an outflow opening, the tube insert first flow path inflow opening being in communication with the helical heat exchanger coolant inlet, the tube insert first flow path outflow opening being in communication with the helical heat exchanger coolant outlet, the tube insert second flow path inflow opening being in communication with the helical heat exchanger charge air inlet, and the tube insert second flow path outflow opening being in communication with the helical heat exchanger charge air outlet. At least one coolant outlet manifold connects each of the outlet tank coolant outlets to the helical heat exchanger coolant inlet, wherein liquid coolant may flow from the engine through the plurality of inlet tanks and associated plurality of cores, transfer heat through to air passing over the fins, pass through the at least one coolant outlet manifold into the helical heat exchanger coolant inlet, absorb heat transferred through the thermally conductive tube insert from the charge air in the tube insert second flow path, and pass out the helical heat exchanger coolant outlet back to the engine. Pressurized charge air may flow from the helical heat exchanger charge air inlet through the tube insert second flow path, transfer heat through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and pass out the helical heat exchanger charge air outlet back to the engine. In an embodiment, the combination radiator and charge air cooler system core tubes and fins may be made of aluminum, and the inlet and outlet tanks may be made of a polymer.

In a further embodiment, the combination radiator and charge air cooler system may include a plurality of radiators, each radiator comprising an inlet tank vertically arrayed, an associated core with tubes horizontally arrayed, and an associated outlet tank vertically arrayed, wherein the helical heat exchanger tube is vertically arrayed and includes a pair of coolant inlets, with one coolant inlet being disposed on one side of the helical heat exchanger tube and the other coolant inlet being disposed on the other side of the helical heat exchanger tube, and wherein the radiators are arranged in pairs with a first pair of radiators having one radiator above the other radiator on the one side of the helical heat exchanger tube and a second pair of radiators having one radiator above the other radiator on the other side of the helical heat exchanger tube, and including a pair of the coolant outlet manifolds, with one coolant outlet manifold connecting each of the outlet tank coolant outlets of the first pair of radiators to the one helical heat exchanger coolant inlet and the other coolant outlet manifold connecting each of the outlet tank coolant outlets of the second pair of radiators to the other helical heat exchanger coolant inlet. In yet another embodiment, the combination radiator and charge air cooler system may further include a pair of coolant inlet manifolds, with one coolant inlet manifold connecting each of the inlet tank coolant inlets of the first pair of radiators to the engine and the other coolant inlet manifold connecting each of the inlet tank coolant inlets of the second pair of radiators to the engine. In yet another aspect, the present invention is directed to a helical heat exchanger for cooling pressurized charge air from a turbo- or supercharger on the engine using liquid coolant from the engine. The helical heat exchanger comprises a tube having first and second ends and a length therebetween, a plurality of coolant inlets for receiving liquid coolant from the engine, a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving the pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine. A thermally conductive tube insert has an outer diameter substantially equal to the inner diameter of the tube, the tube insert having first and second ends and comprising a helix extending along the length of the tube insert and twisted around a central axis, the tube insert sealed within the tube by sealing an outer edge of the helix to an inner surface of the tube to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the tube. A plurality of inflow openings to the tube insert first flow path spaced along the tube length are in communication with the tube liquid coolant inlets, and a tube insert first flow path outflow opening is in communication with the tube liquid coolant outlet. An inflow opening to the tube insert second flow path is in communication with the tube charge air inlet, and a tube insert second flow path outflow opening is in communication with the tube charge air outlet, wherein liquid coolant may enter into the helical heat exchanger tube at different first flow path inflow openings and combine to pass through the tube insert first flow path and out the tube coolant outlet back to the engine such that the liquid coolant may absorb heat transferred through the thermally conductive tube insert from the charge air in the tube insert second flow path. Pressurized charge air may flow from the tube charge air inlet through the tube insert second flow path, transfer heat through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and pass out the tube charge air outlet back to the engine.

In an embodiment, the helical heat exchanger helix has a predetermined pitch defining a length of the first and second fluid flow paths within the helical heat exchanger, wherein the pitch of the helix is constant along the length of the tube insert. In another embodiment, the pitch of the helix may vary along the length of the tube insert from a minimum adjacent the first end of the tube to a maximum adjacent the second end of the tube.

In yet another aspect, the present invention is directed to a method of cooling pressurized charge air from a turbo- or supercharger on an engine. The method includes providing a combination radiator and charge air cooler comprising: a core for cooling the liquid engine coolant, the core having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes; an inlet tank having a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, the inlet tank being connected between the first and second ends to the inlet ends of the tubes of the core; and an outlet tank having a first end and a second end, and having a first portion and a second portion between the first and second ends, the outlet tank first portion being connected between the first and second ends to the outlet ends of the tubes of the core. The outlet tank has an opening between the outlet tank first portion and the outlet tank second portion. The outlet tank second portion has a coolant outlet, a charge air inlet, and a charge air outlet, the outlet tank second portion further having an inner diameter and a thermally conductive tube insert having an outer diameter substantially equal to the inner diameter of the second outlet tank portion. The tube insert has first and second ends and comprising a helix extending along a length of the tube insert and twisted around a central axis, the tube insert sealed within the outlet tank second portion by sealing an outer edge of the helix to an inner surface of the outlet tank second portion to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the outlet tank second portion, respectively. The tube insert first flow path has an inflow opening in communication with the opening between the outlet tank first and second portions and an outflow opening in communication with the outlet tank second portion liquid coolant outlet. The tube insert second flow path has an inflow opening in communication with the outlet tank second portion pressurized charge air inlet and an outflow opening in communication with the outlet tank second portion pressurized charge air outlet. The method further includes the steps of: passing liquid coolant from the engine through the inlet tank coolant inlet and the tubes through the core; transferring heat from liquid coolant in the core tubes to air passing over the fins to cool the liquid coolant; passing cooled liquid coolant from the core tubes through the outlet tank coolant outlet to the outlet tank first portion, through the opening to the outlet tank second portion and the tube insert first flow path inflow opening, and through the tube insert first flow path; passing pressurized charge air from the a turbo- or supercharger on an engine through the charge air inlet of the outlet tank second portion, to the tube insert second flow path inflow opening, and through the tube insert second flow path; transferring heat from the pressurized charge air in the tube insert second flow path through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and absorbing the heat transferred from the charge air to the liquid coolant in the tube insert first flow path; passing the liquid coolant out the outlet tank second portion coolant outlet back to the engine; and passing cooled pressurized charge air out the outlet tank second portion charge air outlet back to the engine.

In an embodiment, a thermally conductive common wall may separate the outlet tank first and second portions, wherein the opening between the outlet tank first portion and outlet tank second portion is in the common wall, and the method may further comprise the step of: transferring heat through the thermally conductive common wall between liquid coolant in the outlet tank first portion and liquid coolant in the tube insert first flow path in the outlet tank second portion, and between liquid coolant in the outlet tank first portion and pressurized charge air in the tube insert second flow path in the outlet tank second portion.

In still another aspect, the present invention is directed to a method of cooling pressurized charge air from a turbo- or supercharger on an engine. The method includes providing a helical heat exchanger for cooling pressurized charge air from a turbo-or supercharger on the engine using liquid coolant from the engine, comprising: a tube having first and second ends and a length therebetween, a plurality of coolant inlets for receiving liquid coolant from the engine, a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving the pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine. The tube has an inner diameter. A thermally conductive tube insert has an outer diameter substantially equal to the inner diameter of the tube, the tube insert having first and second ends and a helix extending along the length of the tube insert and twisted around a central axis. The tube insert is sealed within the tube by sealing an outer edge of the helix to an inner surface of the tube to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the tube. A plurality of inflow openings to the tube insert first flow path spaced along the tube length are in communication with the tube liquid coolant inlets, and a tube insert first flow path outflow opening is in communication with the tube liquid coolant outlet. An inflow opening to the tube insert second flow path is in communication with the tube charge air inlet, and a tube insert second flow path outflow opening is in communication with the tube charge air outlet. The method includes the steps of: flowing liquid coolant into the helical heat exchanger tube at different first flow path inflow openings along the tube length and combining the liquid coolant to flow through the tube insert first flow path; flowing pressurized charge through the tube charge air inlet into the tube insert second flow path; transferring heat from the pressurized charge air in the tube insert second flow path through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and absorbing the heat transferred from the charge air to the liquid coolant in the tube insert first flow path; and passing the liquid coolant out the tube coolant outlet back to the engine; passing cooled pressurized charge air out the tube charge air outlet back to the engine.

In an embodiment of the method, the helix may have a predetermined pitch defining a length of the first and second fluid flow paths within the helical heat exchanger, wherein the pitch of the helix varies along the length of the tube insert from a minimum adjacent the first end of the tube to a maximum adjacent the second end of the tube, and wherein the liquid coolant is flowed through the different first flow path inflow openings into the tube insert helix at different pitches of the helix.

Brief Description of the Drawings

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: Fig. 1 is a perspective view of one embodiment of a charge air cooler with a helical insert according to the present invention.

Fig. 2 is a perspective view of the charge air cooler with helical insert shown in Fig. 1 , with the outer tube or shell removed to show a helical insert having a constant pitch along the length thereof.

Fig. 3 is an end view of the charge air cooler of Figs. 1-2.

Fig. 4 is a top, cross-sectional view of the charge air cooler of Figs. 1-3.

Fig. 5 is a perspective view of another embodiment of a helical insert for a charge air cooler according to the present invention, wherein the helix has a constant pitch along the length of the insert, but the helix is more tightly twisted to produce longer fluid flow paths as compared to the helical insert of Fig. 2.

Fig. 6 is a perspective view of another embodiment of a helical insert according to the present invention, wherein the pitch of the helix varies along the length of the insert. Fig. 7 is a front elevational view of one embodiment of a cooling package according to the present invention, wherein cooled coolant from the outlet tank of the radiator is fed directly into one end of the charge air cooler.

Fig. 8 is a front elevational view of another embodiment of a cooling package according to the present invention, with three radiators mounted in parallel and wherein the combined coolant outflow is fed into the charge air cooler.

Fig. 9 is a front elevational, partially cutaway view of yet another embodiment of a cooling package according to the present invention, with three radiators mounted in parallel and wherein the coolant outflow of each radiator is fed into the charge air cooler at three different inlet segments of the charge air cooler. Fig. 10 is a front elevational view of yet another embodiment of a cooling package according to the present invention, with two radiators mounted in parallel and on either side of a charge air cooler, wherein coolant outflow from each radiator is fed into one end of the charge air cooler.

Fig. 1 1 is a front elevational view of still yet another embodiment of a cooling package according to the present invention, with three pairs of radiators mounted in parallel and on either side of a charge air cooler, wherein coolant outflow from each radiator is fed into one end of the charge air cooler.

Fig. 12 is a front elevational view of still yet another embodiment of a cooling package according to the present invention, with three pairs of radiators mounted in parallel and on either side of a charge air cooler, wherein coolant outflow from each pair of radiators is fed into the charge air cooler at three different inlet segments of the charge air cooler.

Fig. 13 is a front elevational view of yet another embodiment of a cooling package according to the present invention, with two pairs of radiators mounted in parallel and on either side of a charge air cooler, and wherein the radiator cores are pjastic tank aluminum radiators connected to the charge air cooler by manifolds.

Fig. 14 is an end view of the outlet tank and charge air cooler portion of the cooling package shown in Fig. 7.

Mode(s) for Carrying Out the Invention

In describing the embodiments of the present invention, reference will be made herein to Figs. 1-14 of the drawings in which like numerals refer to like features of the invention.

Certain terminology is used herein for convenience only and is not to be taken as a limitation of the invention. For example, words such as "upper," "lower," "left," "right," "horizontal," "vertical," "upward," "downward," "clockwise," "counterclockwise," "longitudinal," "lateral," "radial," or the like merely describe the configuration shown in the drawings. Indeed, the referenced components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. For purposes of clarity, the same reference numbers may be used in the drawings to identify similar elements.

Additionally, in the subject description, the words "exemplary," "illustrative," or the like are used to mean serving as an example, instance, or il lustration. Any aspect or design described herein as "exemplary" or "il lustrative" is not necessarily intended to be construed as preferred or advantageous over other aspects or design. Rather, the use of the words "exemplary" or "illustrative" is merely intended to present concepts in a concrete fashion.

A charge air cooler is used to cool engine air after it has passed through a turbocharger, but before it is routed into the engine. The idea is to return the air to a lower temperature, for optimum power from the combustion process within the engine. More specifically, a charge air cooler is a heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air-charge density through isochoric cooling. A decrease in air intake temperature provides a denser intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine.

Charge air coolers range in size depending on the engine. The smallest are most often referred to as intercoolers and are attached to automobile or truck engines. The largest are often used on huge marine diesel engines or in power plants, and can weigh several tons. The present invention is directed to an improved heat exchanger package which combines a charge air cooler including a helical insert comprising a single helix, with one or more engine cooling radiators coupled thereto, in order to reduce the overall size of the cooling package. Referring now to Fig. 1 , a perspective view of an illustrative embodiment of a heat exchanger or charge air cooler with a helical insert according to the present invention is shown. In the illustrative embodiment shown, the charge air cooler comprises a tube or shell 10 of substantially circular cross-section, having a length L1 and first and second ends 12, 22, and a helical insert sealed therein. Tubes having a circular-shaped axial cross-section (i.e., perpendicular to the axis of the tube) are typically utilized for optimum heat transfer performance of a heat exchanger, although other tube shapes and cross-sections may also be utilized. The ends of the tube 10 may be sealed by a first end cap 14 and second end cap 24 to form a self-contained heat exchanger assembly unit. Preferably, the end caps 14, 24 are flat plates which are sealed flush with the ends of the tube and helical insert to prevent fluid mixing at the interior ends of the heat exchanger assembly. The first and second end caps 14, 24 may be secured and sealed to the respective ends of the tube and helical insert by welding, solder baking, brazing or other equivalent process known to those in the art. It should be understood by those skilled in the art that the illustrative embodiment shown in Fig. 1 depicts a complete, self-contained heat exchanger assembly unit for purposes of describing the characteristics of the helical insert according to the present invention, and that the charge air cooler of the present invention is not necessarily of tubular shape. Rather, for simplicity, a tubular heat exchanger is being used to illustrate the heat exchange characteristics of the helical insert in a concrete manner.

The helical insert, and optionally, the tube, may each be made of thermally conductive metal, such as aluminum or copper alloys. All parts of the heat exchanger may be made of an aluminum al loy clad with a brazing alloy, and the unit may be flux brazed in a cab (controlled atmosphere brazing) furnace, as per standard aluminum liquid-to-liquid heat exchanger manufacturing techniques. Brazing of the entire unit ensures that the edges of the helix, which are in a tight fit against the inner surface of the tube, become sealed thereto, and that the ends of the helix are sealed to the respective end caps, such that two distinct fluid-tight fluid flow paths are created and no common fluid is al lowed to flow on both sides of the helix in the same direction, ensuring optimal heat transfer.

Tube 10, representing a charge air cooler of the present invention, includes a plurality of inlet and outlet ports for passage of charge air and engine coolant into and out of the heat exchanger assembly. As shown in Fig. 1 , the heat exchanger assembly of the present invention includes a first fluid inlet port 40 and outlet port 42, and a second fluid inlet port 50 and outlet port 52. The first fluid flow path is depicted in direction 41 , and the second fluid flow path is depicted in direction 51. In operation of the heat exchanger, inlet and outlet fluid lines (not shown) for first fluid flow path 41 are connected to inlet and outlet ports 40 and 42, respectively, and inlet and outlet fluid lines (not shown) for second fluid flow path 51 are connected to inlet and outlet ports 50 and 52, respectively. A first fluid then enters flow path 41 and a second fluid then enters flow path 51 through the respective sets of inlet and outlet ports, and through the respective fluid flow paths respectively, in counterflow operation. As shown in Fig. 1 , the fluid connection fittings are positioned per design requirements, and may be positioned, for example, on either ends of the tube, so long as the fittings are arranged for counterflow operation.

Referring now to Fig. 2, the outer tube or shell 10 has been removed to more particularly show one embodiment of a helical insert 100 having a length L2 and a substantially circular outer diameter which is approximately equal to the inner diameter of tube 10. Insert 100 is comprised of a single helix 120 extending along the length L2 of tube insert 100 and twisted around a phantom central axis A. In a normal configuration, helix first end 121 may be adjacent tube first end 12, and helix second end 124 is adjacent tube second end 22. The first end 121 of the helix is sealingly contacting an inner surface of tube end cap 14 and the second end of the helix is sealingly contacting an inner surface of tube end cap 24. In the embodiment shown in Fig. 2, the pitch p of the helical convolutions of the helix 120 is constant along the length of the insert 100 and is greater than the inner diameter d of the heat exchanger tube 10, thereby creating two fluid flow paths, each with increased length over that of a typical heat exchanger tube. Alternatively, the pitch p of the helical convolutions may be less than or equal to the inner diameter of the heat exchanger tube, as shown in Fig. 4. Such a configuration will result in an even longer fluid flow path than if the pitch were greater than the inner diameter of the tube. As used herein, the pitch of a helical convolution is defined as the axial advance of a point during one complete rotation.

As further shown in Fig. 2, the helical insert 100 may have a substantially circular outer diameter which is nominal ly smal ler than the inner diameter d of tube 10, to allow for a sliding fit therein. During assembly of the heat exchanger, tube insert 100 may be slideably inserted into either of tube ends 12, 22 and in the direction of the opposing tube end. Helical insert 100 does not extend substantially beyond the first and second tube ends 12, 22. After insertion, the outer edges of the helix 120 are sealed to the inner surface 1 1 of tube 10, such as by brazing, to create fluid- tight fluid flow paths 41 , 51 . Any suitable sealing material may be employed between the edge of the helix and tube 10. In one or more embodiments, tube 10 may be mechanically swaged, or compressed, onto the outer edges of helix 120 prior to brazing, which may act to form an improved seal. Helical insert 100 may be installed manually or by automation during assembly of the heat exchanger unit. After installation, end caps 14, 24 are sealed to tube ends 12, 22, and helix ends 121 , 124, respectively, to form fluid-tight fluid flow paths 41 , 51 inside the heat exchanger assembly.

In an embodiment, the ends of helix 120 are oriented such that the helix is seal i ngly contacting the inner surface of respective end caps along a line intermediate adjacent fluid connection fittings to create two fluid-tight fluid flow paths which track the opposing sides of the helix during each helical convolution. Fig. 3 shows an end view of the embodiment of the charge air cooler shown in Figs. 1-2, showing first fluid inlet port 40 and second fluid outlet port 52 disposed on and integral with end cap 14. Fluid connection fittings 40, 52 and 42, 50 (not shown) are arranged for counterflow operation. As further shown in Fig. 3, helix first end 121 sealingly contacts an inner surface of end cap 14 intermediate first fluid inlet 40 and second fluid outlet 50, such that first fluid flow path 41 is fluid- tight between side 122 of the helix and the inner surface of tube 10, and second fluid flow path 51 is fluid-tight between side 123 of the helix and the inner surface of tube 10. The first and second fluids flow in opposite directions through the respective fluid paths between alternating convolutions of the helix to cool one of the fluids by transferring heat through the helix to the other fluid.

Fig. 4 depicts a top cross-sectional view of the assembled heat exchanger with helical insert, as shown in Figs. 1-2. As shown in Fig. 4, helix 120 comprises a first side 122 and an opposing second side 123 defining a series of convolutions along length L2. The helical convolutions are offset by a predetermined spacing or distance along the length of tube insert 100, creating two distinct fluid flow paths 41 , 51 between the helical convolutions. First fluid flow path 41 begins at tube inlet 40 and ends at tube outlet 42, and is defined between side 122 of the helix and the inner surface 1 1 of the tube or shell 10, while second fluid flow path 51 begins at tube inlet 50 and ends at tube outlet 52 and is defined between side 123 of the helix and the inner surface of the tube. As depicted in Fig. 4, the pitch p of the helical convolutions of helix 120 is constant along the length of the tube insert and is greater than the inner diameter d of the heat exchanger tube 10 and defines two fluid flow paths, each with increased length over that of a conventional heat exchanger tube.

An advantage of the helical insert of the present invention is that because the insert comprises a single helix, the heat exchanger assembly can uniquely take advantage of nano-conductor and superconductor materials available today by focusing on the conductive elements of heat transfer and optimizing convective resistance. The single helix provides for much greater flexibility in pitch and heat exchanger chamber/channel design over that of prior art heat exchangers, for example, the helix may be twisted per design requirements to be extremely tight and/or comprise a variable pitch over the length of the insert. Such twisting flexibility allows for an increase in heat transfer surface area while optimizing hydraulic diameter and flow characteristics with low flow resistance.

Prior art helical heat exchangers typically comprise at least two helices, which prevents the manufacture of a helical insert having a pitch as short as can be achieved in the present invention, and prevents the manufacture of a helical insert having a variable pitch over the length of the insert, as the multiple helices would interfere with each other. An example of a tighter twisting of the helix is depicted in Fig. 5, showing helical insert 200 comprising a helix 220 having an outer diameter d' and a pitch p' that is substantially shorter than the pitch p of helix 120. The outer diameter d' of insert 200 is nominally smaller than the inner diameter of the heat exchanger tube (not shown), to allow for a sliding fit therein. As shown in Fig. 5, the ratio of pitch p' to diameter d' of helix 220 may be about (p' / d' = 0.38), whereas the ratio of pitch p to diameter d of helix 120 may be about (p / d = 2). It should be understood by those skilled in the art that the pitch p' is not intended to represent the minimum pitch achievable by the present invention, and is being shown for exemplary purposes only. In general, the shorter the pitch, the longer the fluid flow path that can be achieved.

In another embodiment, the pitch of the helix (and therefore the offset spacing between adjacent helical convolutions) may be varied over the length of the fluid flow path, which is more conducive to phase cooling, and is particularly applicable for utilization in vehicle battery cooling, for example, as will be described in more detail below. This is shown, for example, in Fig. 6 where the pitch p1 of the helix 320 near end 321 is longer than the pitch p2 at the opposing end 324 of the helix, and the pitch gradual ly decreases along the length of the tube insert beginning from end 321 . Having a longer pitch p1 along a portion of the length of the helical insert at one end of the heat exchanger allows for increased flow path area of the first and second fluids in this section of the heat exchanger to account for volume changes of the respective fluids as the temperature changes during the heat exchange process. In that the pitch of the helix may be variable over the length of the fluid flow path, the present invention thus allows for more flexibility in spiral density for control ling fluid flow velocity and Reynold's Number, thereby increasing heat transfer performance over conventional heat exchangers. More specifically, primary heat transfer surface area can be added with little pressure drop as Reynold's Number is optimized through flexible chamber/channel design.

In at least one embodiment of the present invention, projections such as tabulating dimples or ridges of various shapes may be incorporated by deformation or embossment of the helix to provide turbulation. In one embodiment, as shown in Fig. 6, the helical insert may have turbulating dimples 340 having an oval shape within the fluid flow paths created by and defined between each side of helix 320 and the inner surface of the tube (not shown). The projections may have alternative shapes such as circular, triangular, or other geometrical shape. The projections or dimples promote transfer of heat from a heated first fluid to a second cooled fluid through the helix during operation of the liquid-to-liquid heat exchanger of the present invention.

The charge air cooler with helical insert may be coupled to one or more engine cooling radiators as part of a heat exchange package for use in motor vehicles, including diesel-electric generator sets where very large cooling packages are normally required, to achieve a minimal overall cooling package size. In general, the present invention provides a heat exchanger assembly or package comprising at least two heat exchangers, such as a radiator and a charge air cooler, packaged or configured in an arrangement for series or parallel air flow therethrough, or a combination of series and parallel air flow. The heat exchanger package according to the present invention can be manufactured in a variety of sizes and shapes complimentary with the engine compartment dimensions of a motor vehicle. In some embodiments, such as an over-the-road highway truck or bus, the heat exchanger package is manufactured in a low and wide configuration to provide the optimal geometry for current truck and bus heat engine compartments. The hood and body front end of heavy duty vehicles such as trucks typically slope downward toward the front of the vehicle to enhance the aerodynamics of the vehicle. The aerodynamic body style affects the dimensions of the engine compartment of the vehicles and presents challenges to heat exchanger designers to fit effective and efficient heat exchangers within the engine compartment. The heat exchanger package of the present invention provides a design solution by enabling a smaller height than length (i.e., across the width of the vehicle), which readily fits within the engine compartment of vehicles having the aerodynamic body style. The geometry of the heat exchanger package according to the present invention is also adapted for compact installations in the rear of buses, where there are also height limitations. Notwithstanding height limitations in certain applications, the heat exchanger package of the present invention may be used in other orientations where such height limitations are not present.

Typically, a suction fan is used to generate air flow through the heat exchanger package. A suction fan is one that is positioned in the stream of airflow on one side of the heat exchanger package, and sucks or forces outside, ambient air first through the heat exchanger components, and then through the fan. While suctions fans are preferred, the present invention is also useful with blower fans that flow air in the opposite direction, first through the fan and then through the heat exchanger components. A fan shroud positioned circumferentially around the fan blades is commonly used to contain and direct the airflow.

Referring now to Fig. 7, a first illustrative embodiment of a heat exchange package according to the present invention is shown, including a first heat exchanger or radiator (RAD) 400, and a second heat exchanger or charge air cooler (CAC) 500. The radiator 400 and charge air cooler 500 are normally in the upstanding, essentially vertical position shown and both include otherwise conventional cores 402, 502, respectively, having front and rear faces and comprising aluminum or brass fluid tubes 404 and aluminum or copper cooling fins 406 in thermal contact with the tubes for transferring heat from the coolant 60 to air passing over the fins. Each radiator core tube has an inlet end 404a sealingly attached to inlet tank 410 between the tank first and second ends and an outlet end 404b sealingly attached to outlet tank or manifold 420. The cores may be comprised of otherwise conventional copper/brass soldered construction, copper/brass brazed construction (CuproBraze^®) or CAB (controlled atmosphere brazing) aluminum construction, and headers (not shown) may be sealing attached at opposite ends of the cores tubes for connection to the tanks or manifolds. The radiator 400 cools a first fluid, liquid engine coolant, and the charge air cooler 500 cools a second fluid, compressed air.

Radiator 400 includes an inlet tank or manifold 410 having first and second ends 410a, 410b and an inlet 412 for receiving engine coolant, and an outlet tank or manifold 420 having first and second ends 420a, 420b attached on either side of core 402 at opposite ends of the length of the radiator, and extending essentially the full width of the radiator. Outlet tank 420 comprises a first portion for receiving cooled coolant from the core, and a second portion comprising charge air cooler 500, wherein the first and second portions are generally separated by a thermally- conductive common wall. The charge air cooler comprises inlet/outlets 512, 522 for receiving pressurized charge air and passing cooled pressurized charge back to the engine, and a coolant outlet 532 for passing liquid coolant back to the engine. The radiator and charge air cooler tanks or manifolds may be made of plastic, or may be constructed of metal such as aluminum or brass, or other suitable materials. The total measurements of the heat exchanger package are preferably consistent with the height and width requirements for motor vehicle engine compartments, and the thickness or depth of the radiator 400 and charge air cooler 500 may be determined by the particular cooling and space requirements of the application. A frame structure (not shown) supports the heat exchanger package and is positioned within the vehicle engine compartment.

In the heat exchange package shown in Fig. 7, charge air cooler 500 comprises a liquid cooled charge air cooler (LCCAC), wherein heated coolant 60 enters radiator 400 through inlet 41 2 and flows vertically between tank 410 and manifold 420 through tubes 404 of radiator core 402 before the outflow is fed directly into one end of charge air cooler 500. Charge air cooler 500 comprises a first portion and a second portion between first and second ends 420a, 420b, with the first portion being connected to the outlet ends 404b of the core tubes 404 for receiving coolant from the radiator core 402, and the second portion comprising charge air cooler 500. In one or more embodiments, an otherwise conventional header (not shown) sealingly connects the outlet ends 404b of the core tubes 404 to tank 420, and manifold 420 includes an opening or port 416 in a common wal l 41 5 between the first and second portions allowing for coolant 60 to enter the charge air cooler. The common wall may be comprised of thermally conductive material to permit heat flow between the coolant and pressurized charge air in the outlet manifold first and second portions, respectively. In an embodiment, the opening or port 416 is adjacent the second end 420b of the charge air cooler. It should be understood by those skilled in the art that the present invention is not limited to liquid cooled charge air coolers, and that air-to-air charge air coolers may also be utilized. The charge air cooler is preferably arranged for counterflow operation, whereby heated charge air 70 enters charge air cooler 500 through inlet 512 and flows in an opposing direction to the liquid coolant from the engine for transferring heat therebetween, before exiting the heat exchange package through charge air outlet 522 and being sent back to the engine.

In one or more embodiments, as best seen in Fig. 14, charge air cooler 500 includes a helical insert comprising a single helix, such as helix 120 described above, whereby the coolant 60 and charge air 70 flow in opposite directions through respective fluid-tight flow paths which track the opposing sides of the helix, thereby cooling the charge air by transferring heat between the heated charge air and the coolant through the helix. In an embodiment, as shown in Fig 14, charge air cooler 500 may be general ly tubular in shape, wherein the outer diameter of the helical insert is substantially equal to the inner diameter of the charge air cooler 500, such that the helical insert may be sealed within the charge air cooler by sealing an outer edge of the helix to the inner surface 51 1 of the charge air cooler to form fluid-tight flow paths defined between opposing sides 122, 123 of the helix and the inner surface 51 1 of the charge air cooler 500. The first fluid flow path has an inflow opening in communication with the opening 41 6 between the outlet manifold 420 first and second portions and an outflow opening in communication with the coolant outlet 532, and the second fluid flow path has an inflow opening in communication with charge air cooler inlet 512 and an outflow opening in communication with charge air cooler outlet 522. In at least one embodiment, outlet 522 is adjacent the charge air cooler first second end 420b and inlet 512 is adjacent the charge air cooler first end 420a.

In one or more embodiments of the present invention, a charge air cooler comprising a helical insert may be coupled to a plurality of radiators arranged for parallel or series flow. Fig. 8 shows a modular heat exchange package comprising multiple engine cooling radiators, such as for diesel-electric generator sets where very large cooling packages are normally required. By coupling the radiator(s) to a charge air cooler having a single helical insert in any one of a plurality of different arrangements, per design requirements, a minimal overall cooling package size can be achieved. As shown in Fig. 8, the heat exchange package includes three radiator cores 402 arranged in parallel flow and integrally connected to common inlet and outlet tanks or manifolds 410', 420'. The cores 402 are oriented such that heated coolant 60 enters through inlet 412 in inlet tank 410' and flows through the core tubes which may connected to tank 410' such as through a header (not shown, for clarity) in parallel flow in a horizontal direction between tanks 410', 420', and the combined coolant outflow is fed into a liquid-cooled, counterflow, charge air cooler 500 including a helical insert comprising a single helix, as described above and shown, for example, in Fig. 14. In an embodiment, the pitch p of the helix may be constant along the length of the charge air cooler to maintain consistent flow path area. In other embodiments, as will be described below, the pitch of the helix may vary along the length of the charge air cooler to accommodate volume change as the charge air cools, per design requirements. Fig. 9 depicts another embodiment of a modular heat exchange package comprising multiple engine cooling radiator cores 402 arranged in parallel flow and integrally connected to a common inlet manifold 410'. Each radiator core 402 is connected to separate segments 426, 428, 430 of outlet tank or manifold 420" and feeds coolant outflow into a distinct section of the charge air cooler 500' through separate openings or ports (not shown) in a common wall between the outlet manifold first portion segments and the charge air cooler 500'. In the embodiment shown, the outlet tank segments 426, 428, 430 are divided by walls 422, 424 extending perpendicular to the longitudinal axis of tank 420" to prevent coolant from entering adjacent segments of outlet tank 420". With the entrance of coolant 60 into the charge air cooler from each succeeding radiator core 402 (bottom to top, as shown in Fig. 9), a need for increased flow area occurs.

To accomplish this, the pitch of the helical insert 600 in charge air cooler 500' is increased (i.e., wider offset spacing between adjacent helical convolutions) so that the helical spacing is widest in the section S3 of the charge air cooler where maximum coolant flow occurs. Due to the counterflow arrangement of the charge air cooler, the maximum helical spacing in section S3 occurs where the hottest charge air 70 enters the charge air cooler. The hotter the charge air, the greater the volume and thus the greater flow area required. As the charge air is cooled, and its volume deceases, the charge air 70 enters the sections S2 and then S1 of the charge air cooler with shorter pitch (i.e., closer helical spacing) and reduced flow area. As shown in Fig. 9, the pitch p of the helical insert 600 is varied along its length, such that section S 1 has a shorter pitch than section S2, which has a shorter pitch than section S3. The cooled liquid coolant from each of the cores 402 is combined in the charge air cooler into one coolant flow path and then passed out of the coolant outlet 532 back to the engine.

Referring now to Fig. 10, yet another embodiment of a modular heat exchange package according to the present invention is shown, comprising a pair of radiator cores 402 mounted in parallel on either side of a counterflow, single helix charge air cooler 500. Coolant 60 enters the heat exchanger assembly through inlets 412 on opposing ends of the assembly and flows in parallel flow horizontally through tubes 404 in cores 402 between inlet tanks 410 and the first and third outer portions of outlet manifold 420. As shown in Fig. 10, charge air cooler 500 comprises the outlet manifold second or midportion and is disposed between the outlet tank first and third outer portions which are sealingly connected to the cores 402. An otherwise conventional header (not shown) sealingly connects the ends of the core tubes 404 to the inlet tanks 410 and outer portions of common manifold 420, and each portion of common tank 420 includes an opening or port (not shown) in a common wall 415 between the outlet tank and the charge air cooler, respectively, allowing for coolant 60 to then enter the charge air cooler 500 disposed therebetween and coupled thereto. Each common wall may be comprised of thermally conductive material to permit heat flow between the coolant and pressurized charge air in the outlet manifold outer portions, respectively. In the embodiment shown, the cooled coolant enters the charge air cooler at the first end thereof and the heated charge air enters the charge air cooler at the opposing end. The coolant entering from either side of the charge air cooler is combined into one flow path and the coolant and pressurized charge air then flow in counterflow through fluid-tight flow paths defined between opposing sides of the helix and the inner surface of the charge air cooler 500 to transfer heat therebetween.

In another embodiment, the heat exchange package may comprise two or more pairs of radiator cores 402 mounted in parallel on either side of a counterflow, single helix charge air cooler 500, as shown in Fig. 1 1 . Coolant 60 enters the heat exchanger assembly through inlets 412 on opposing ends of the assembly and flows in parallel flow horizontally through tubes in cores 402 between inlet tanks 410 and manifold 420'. An otherwise conventional header (not shown) sealingly connects the ends of the core tubes 404 to manifold 420', and the outer portions of manifold 420' include an opening or port on the common wall between the outlet tank outer portions and the charge air cooler, respectively, allowing for coolant 60 pass through to the charge air cooler. The combined coolant flow 60 from all of the radiators 402 is fed into one end of the helical charge air cooler 502 and combined into one flow path, and the coolant and pressurized, heated charge air 70 then flow in counterflow through the charge air cooler to transfer heat therebetween.

In still yet another embodiment, as shown in Fig. 12, the heat exchange package may comprise two or more pairs of radiator cores 402 mounted in paral lel on either side of a counterflow, single helix charge air cooler core 500', with the cores on each side of the charge air cooler being integrally connected to common inlet tanks 410'. Similar to the embodiment shown in Fig. 9, each radiator core 402 is connected to separate, fluid-tight segments of the first portions of outlet manifold 420" and feed coolant outflow into a distinct section of the charge air cooler 500' through separate openings or ports (not shown) in a common wall therebetween. As in the embodiment shown in Fig. 9, the pitch of the helical insert 600 in charge air cooler 500' is varied along the length thereof so that the helical spacing is widest in the section S3 of the charge air cooler where maximum coolant 60 flow occurs, which is also where the hottest charge air 70 enters the charge air cooler. The variation in helical spacing also accommodates the counterflow heated charge air, which reduces in volume as it cools during passage through the charge air cooler. The hotter the charge air, the greater the volume and thus the greater flow area required. As the charge air is cooled, and its volume deceases, the charge air 70 flows through sections S2 and then S1 of the charge air cooler with shorter pitch (i.e., closer helical spacing) and reduced flow area. As shown in Fig. 12, section S1 has a shorter pitch than section S2, which has a shorter pitch than section S3. The cooled liquid coolant from each of the cores 402 is combined in the charge air cooler into one coolant flow path and then passed out of the coolant outlet 532 back to the engine.

It should be understood by those skilled in the art that while Figs. 7-12 generally depict heat exchange packages comprises radiators with headered cores attached to common tanks, the same concepts may be achieved by similarly arranging plastic tan aluminum radiators and connecting them by manifolds or other fluid connection means. An example of PTA (plastic tank aluminum) core construction is shown in Fig. 13, depicting a plurality of radiators 402' integrally connected to a plurality of steel tanks 700 and arranged in a similar manner to the embodiment shown in Fig. 4. For clarity, cooling air bypass shields and mounting structure have been omitted. The individual inlet/outlet tanks 430, 440 of each radiator or heat exchanger are connected to side inlet tanks 700A, 700B and charge air cooler 500, respectively, such as by means of one or more hoses. As shown in Fig. 13, radiator tanks 430 are inlet tanks including headers (not shown) for passage of coolant into the radiators, whereas radiator tanks 440 are outlet tanks and include headers (not shown) for passage of coolant out of the radiators and into the charge air cooler 500. In at least one embodiment, as shown in Fig. 13, coolant enters the heat exchanger package through inlets 432 in side, opposing coolant tanks 700A, 700B, flows through the plurality of hoses into radiator inlet tanks 430 and then flows horizontally in parallel flow through a plurality of radiator core tubes in horizontally adjacent radiators or heat exchangers 402', through radiator outlet tanks 440 to a charge air cooler 500 by way of one or more hoses or other fluid connection means. Charge air cooler 500 comprises a helical insert including a single helix and is arranged for counterflow operation, as described above.

In a typical PTA core construction, the core tubes and fins are made of aluminum or an aluminum alloy, and may be clad or coated with braze material, but other metals and alloys may also be used. The tubes are inserted into, and sealed to, openings in the walls of an aluminum inlet header and outlet header, respectively, to make up the core. The headers are connected to, or part of, plastic inlet and outlet tanks or manifolds and structural side pieces connect the tanks to complete the heat exchanger. Each of the tubes has a tube end secured in an opening in the header wall to form a tube-to-header joint. Oval tubes are typically utilized for close tube spacing for optimum heat transfer performance of the heat exchanger, although other tube shapes and cross-sections may be utilized. The tube-to-header joint is typically brazed to prevent leakage around the tubes and header. Thus, the present invention provides one or more of the following advantages. The integrated heat exchanger assembly of the present invention provides a more compact and efficient cooling package, which takes up less engine compartment or generator set space. In addition, the cooling package of the present invention utilizes less material than those of the prior art, thereby costing significantly less to produce. By utilizing less material, the cooling package also weighs less than those of the prior art.

While the present invention has been particularly described, in conjunction with one or more specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as fal ling within the true scope and spirit of the present invention.

Thus, having described the invention, what is claimed is:

Claims

1 . A combination radiator and charge air cooler for cooling liquid coolant from an engine and for cooling pressurized charge air from the engine, comprising:

a. core for cooling the l iquid engine coolant, the core having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins;

an inlet tank having a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, the inlet tank being connected between the first and second ends to the inlet ends of the tubes of the core for passing liquid coolant through the core to be cooled; and

an outlet tank having a first end and a second end, and having a first portion and a second portion between the first and second ends, the outlet tank first portion being connected between the first and second ends to the outlet ends of the tubes of the core for receiving cooled liquid coolant from the core;

the outlet tank having an opening between the outlet tank first portion and the outlet tank second portion for passing cooled liquid coolant to the second outlet tank portion; and the outlet tank second portion having a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving the pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine, the outlet tank second portion further having an inner diameter and a thermally conductive tube insert having an outer diameter substantial ly equal to the inner diameter of the second outlet tank portion, the tube insert havi ng first and second ends and comprising a helix extending along a length of the tube insert and twisted around a central axis, the tube insert sealed within the outlet tank second portion by sealing an outer edge of the helix to an inner surface of the outlet tank second portion to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the outlet tank second portion, respectively, the tube insert first flow path having an inflow opening in communication with the opening between the outlet tank first and second portions and an outflow opening in communication with the outlet tank second portion liquid coolant outlet such that liquid coolant may flow from the outlet tank first portion through the tube insert first flow path, absorb heat transferred through the thermally conductive tube insert from the charge air in the tube insert second flow path, and pass out the outlet tank second portion coolant outlet back to the engine, and

the tube insert second flow path having an inflow opening in communication with the outlet tank second portion pressurized charge air inlet and an outflow opening in communication with the outlet tank second portion pressurized charge air outlet such that pressurized charge air may flow from the outlet tank second portion pressurized charge air inlet through the tube insert second flow path, transfer heat through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and pass out the outlet tank second portion pressurized charge air outlet back to the engine.

2. The combination radiator and charge air cooler of claim 1 further including a common wall separating the outlet tank first and second portions, and wherein the opening between the outlet tank first portion and the outlet tank second portion is in the common wall.

3. The combination radiator and charge air cooler of claim 2 wherein the common wal l is made of a thermal ly conductive material to permit heat flow between liquid coolant in the outlet tank first portion and liquid coolant in the tube insert first flow path in the outlet tank second portion, and between liquid coolant in the outlet tank first portion and pressurized charge air in the tube insert second flow path in the outlet tank second portion.

4. The combination radiator and charge air cooler of claim 2 wherein the opening in the common wal l is adjacent the first end of the outlet tank.

5. The combination radiator and charge air cooler of claim 4 wherein the outlet tank second portion pressurized charge air outlet is adjacent the first end of the outlet tank and the outlet tank second portion pressurized charge air inlet is adjacent the second end of the outlet tank.

6. The combination radiator and charge air cooler of claim 5 wherein the tubes are vertical ly arrayed, and the inlet tank is above the outlet tank.

7. The combination radiator and charge air cooler of claim 5, including a plurality of the cores disposed between the inlet and outlet tanks.

8. The combination radiator and charge air cooler of claim 5 wherein the core tubes are horizontal ly arrayed, and the inlet and outlet tanks are vertically arrayed.

9. The combination radiator and charge air cooler of claim 8, including a plurality of the cores disposed between the inlet and outlet tanks.

10. The combination radiator and charge air cooler of claim 7 wherein the core comprises a first core, and the opening between the outlet tank first portion and the outlet tank second portion comprises a first opening, and further including:

a first wal l between the first and second ends of the outlet tank first portion forming separate outlet tank first portion segments, wherein the first core tube outlet ends are connected to the outlet tank first portion segment adjacent the first end such that cooled liquid coolant from the first core may be received into the outlet tank first portion segment adjacent the first end and pass through the first opening between the outlet tank first and second portions;

a second core having the tube inlet ends connected to the inlet tank between the first and second ends for passing liquid coolant through the second core to be cooled and tube outlet ends connected to the outlet tank first portion segment adjacent the second end such that cooled liquid coolant from the second core may be received into the outlet tank first portion segment adjacent the second end; and

a second opening between the outlet tank first portion segment adjacent the second end and the outlet tank second portion, the second opening being in communication with the tube insert first flow path between the inflow opening and the outflow opening, such that cooled liquid coolant from the second core may pass through the second opening between the outlet tank first and second portions, wherein cooled liquid coolant from the first core and cooled liquid coolant from the second core may be combined in the outlet tank second portion in the tube insert first flow path and pass out the outlet tank second portion coolant outlet back to the engine.

1 1 . The combination radiator and charge air cooler of claim 10 wherein the helix has a predetermined pitch, the pitch of the helix defining a length of the first and second fluid flow paths within the outlet tank second portion, and wherein the pitch of the helix varies along the length of the tube insert from a minimum adjacent the first end of the outlet tank second portion to a maximum adjacent the second end of the outlet tank second portion.

12. The combination radiator and charge air cooler of claim 1 0 further includi ng: a second wal l between the first wal l and the second ends of the outlet tank first portion, the first and second wal ls forming separate outlet tank first portion segments of the outlet tank first portion;

a third core having the tube i nlet ends connected to the inlet tank between the first and second cores for passing l iquid coolant through the third core to be cooled and tube outlet ends connected to the outlet tank first portion segment between the first and second cores such that cooled l iquid coolant from the third core may be received into the outlet tank first portion segment between the first and second wal ls; and

a third openi ng in the outlet tank and between the outlet tank first portion segment between the first and second wal ls and the outlet tank second portion, the second opening being in communication with the tube insert first flow path between the inflow openi ng and the outflow opening, such that cooled l iquid coolant from the third core may pass through the third opening between the outlet tank first and second portions, wherein cooled l iquid coolant from the first, second and third cores may be combined in the outlet tank second portion in the tube insert first flow path and pass out the outlet tank second portion coolant outlet back to the engine.

1 3. The combi nation radiator and charge air cooler of claim 5 wherein the core comprises a first core and the inlet tank comprises a first inlet tank, and further incl uding:

a second core for cool ing the liquid engi ne coolant, the second core having a plurality of tubes each having an inlet end and an outlet end, and a pl urality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins; a second inlet tank having a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engi ne, the second inlet tank being connected between the first and second ends to the i nlet sides of the tubes of the second core for passing liquid coolant through the second core to be cooled;

the outlet tank having a third portion between the first and second ends on a side of the outlet tank second portion opposite the outlet tank first portion, the outlet tank being connected to the outlet ends of the tubes of the second core for receiving cooled l iquid coolant from the second core, the second inlet tank being disposed on a side of the outlet tank opposite the first inlet tank, and the second core being disposed between the second i nlet tank and the outlet tank, the outlet tank third portion being connected between the first and second ends to the outlet ends of the tubes of the second core for receiving cooled liquid coolant from the second core; and

a second opening between the outlet tank third portion and the outlet tank second portion for passing cooled liquid coolant to the second outlet tank portion, wherei n the tube insert first flow path inflow opening is i n communication with the second opening between the outlet tank third and second portions such that l iquid coolant may flow from the second core through the outlet tank third portion, through the outlet tank having a second opening and through the tube insert first flow path and out the outlet tank second portion coolant outlet back to the engine.

14. The combination radiator and charge air cooler of claim 13 further including a second thermally conductive common wall separating the outlet tank third and second portions to permit heat flow between liquid coolant in the outlet tank third portion and liquid coolant in the tube insert first flow path in the outlet tank second portion, and between liquid coolant in the outlet tank third portion and pressurized charge air in the tube insert second flow path in the outlet tank second portion, and wherein the second opening between the outlet tank third portion and the outlet tank second portion is in the common wal l.

15. The combination radiator and charge air cooler of claim 5 wherein the inlet tank comprises a first inlet tank and the first inlet tank and the outlet tank are vertically arrayed, and including a first plurality of the cores disposed between the first. inlet tank and the outlet tank, and further including:

a second plurality of the cores for cooling the liquid engine coolant, the second plurality of the cores having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins;

a second inlet tank having a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, the second inlet tank being connected between the first and second ends to the inlet sides of the tubes of the second plurality of cores for passing liquid coolant through the second core to be cooled;

the outlet tank having a third portion between the first and second ends on a side of the outlet tank second portion opposite the outlet tank first portion, the outlet tank being connected to the outlet ends of the tubes of the second plurality of cores for receiving cooled liquid coolant from the second plurality of cores, the second inlet tank being disposed on a side of the outlet tank opposite the first inlet tank, and the second plurality of cores being disposed between the second inlet tank and the outlet tank, the outlet tank third portion being connected between the first and second ends to the outlet ends of the tubes of the second plurality of cores for receiving cooled liquid coolant from the second plurality of cores; and

a second opening between the outlet tank third portion and the outlet tank second portion for passing cooled liquid coolant to the second outlet tank portion, wherein the tube insert first flow path inflow opening is in communication with the second opening between the outlet tank third and second portions such that liquid coolant may flow from the second plurality of cores through the outlet tank third portion, through the outlet tank having a second opening and through the tube insert first flow path and out the outlet tank second portion coolant outlet back to the engine.

16. The combination radiator and charge air cooler of claim 15 further including: at least one wall between the first and second ends of the outlet tank first portion forming separate outlet tank first portion segments, wherein the tube outlet ends of each of the first plurality of cores are connected to an associated outlet tank first portion segment such that cooled liquid coolant from each of the first plurality of cores may be received into the associated outlet tank first portion segment;

at least one wal l between the first and second ends of the outlet tank third portion forming separate outlet tank third portion segments, wherein the tube outlet ends of each of the second plurality of cores are connected to an associated outlet tank third portion segment such that cooled liquid coolant from each of the second plurality of cores may be received into the associated outlet tank third portion segment; and openings between each of the outlet tank first portion segments and the outlet tank second portion, and between each of the outlet tank third portion segments and the outlet tank second portion, the openings being in communication with the tube insert first flow path between the inflow opening and the outflow opening, such that cooled liquid coolant from the first and second plurality of cores may pass through the openings from the outlet tank first and third portion segments to the outlet tank second portion, wherein cooled liquid coolant from the first plurality of cores and cooled liquid coolant from the second first plurality of cores may be combined in the outlet tank second portion in the tube insert first flow path and pass out the outlet tank second portion coolant outlet back to the engine.

1 7. The combination radiator and charge air cooler of claim 1 6 wherein the helix has a predetermined pitch, the pitch of the helix defining a length of the first and second fluid flow paths within the outlet tank second portion, and wherein the pitch of the helix varies along the length of the tube insert from a minimum adjacent the first end of the outlet tank second portion to a maximum adjacent the second end of the outlet tank second portion.

18. A combination radiator and charge air cooler system for cooling liquid coolant from an engine and for cooling pressurized charge air from the engine, comprising:

a plurality of cores for cooling the liquid engine coolant, each core having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes for transferring heat from liquid coolant in the tubes to air passing over the fins; an inlet tank associated with each of the cores having a first end and a second end and a coolant inlet for receiving the liquid coolant from the engine, each inlet tank being connected between the first and second ends to the inlet ends of the tubes of the associated core for passing liquid coolant through the associated core to be cooled;

an outlet tank associated with each of the cores having a first end and a second end and a coolant outlet, each outlet tank being connected between the first and second ends to the outlet ends of the tubes of the associated core for receiving cooled liquid coolant from the associated core;

a helical heat exchanger comprising a tube having first and second ends, a coolant inlet for receiving liquid coolant from the outlet tanks, a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving the pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine, the tube further having an inner diameter and a thermally conductive tube insert having an outer diameter substantially equal to the inner diameter of the tube, the tube insert having first and second ends and comprising a helix extending along the length of the tube insert and twisted around a central axis, the tube insert sealed within the tube by sealing an outer edge of the helix to an inner surface of the tube to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the tube; each of the tube insert first and second flow path having an inflow opening and an outflow opening, the tube insert first flow path inflow opening being in communication with the helical heat exchanger coolant inlet, the tube insert first flow path outflow opening being in communication with the helical heat exchanger coolant outlet, the tube insert second flow path inflow opening being in communication with the helical heat exchanger charge air inlet, the tube insert second flow path outflow opening being in communication with the helical heat exchanger charge air outlet; and

at least one coolant outlet manifold connecting each of the outlet tank coolant outlets to the helical heat exchanger coolant inlet, wherein liquid coolant may flow from the engine through the plurality of inlet tanks and associated plurality of cores, transfer heat through to air passing over the fins, pass through the at least one coolant outlet manifold into the helical heat exchanger coolant inlet, absorb heat transferred through the thermally conductive tube insert from the charge air in the tube insert second flow path, and pass out the helical heat exchanger coolant outlet back to the engine, and

wherein pressurized charge air may flow from the helical heat exchanger charge air inlet through the tube insert second flow path, transfer heat through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and pass out the helical heat exchanger charge air outlet back to the engine.

19. The combination radiator and charge air cooler system of claim 18 wherein the core tubes and fins are made of aluminum, and the inlet and outlet tanks are made of a polymer.

20. The combination radiator and charge air cooler of system claim 19 including a plurality of radiators, each radiator comprising an inlet tank vertically arrayed, an associated core with tubes horizontally arrayed, and an associated outlet tank vertical ly arrayed, wherein the helical heat exchanger tube is vertical ly arrayed and includes a pair of coolant inlets, with one coolant inlet being disposed on one side of the helical heat exchanger tube and the other coolant inlet being disposed on the other side of the helical heat exchanger tube, and wherein the radiators are arranged in pairs with a first pair of radiators having one radiator above the other radiator on the one side of the helical heat exchanger tube and a second pair of radiators having one radiator above the other radiator on the other side of the helical heat exchanger tube, and including a pair of the coolant outlet manifolds, with one coolant outlet manifold connecting each of the outlet tank coolant outlets of the first pair of radiators to the one helical heat exchanger coolant inlet and the other coolant outlet manifold connecting each of the outlet tank coolant outlets of the second pair of radiators to the other helical heat exchanger coolant inlet.

21 . The combination radiator and charge air cooler system of claim 20 further including a pair of coolant inlet manifolds, with one coolant inlet manifold connecting each of the inlet tank coolant inlets of the first pair of radiators to engine and the other coolant inlet manifold connecting each of the inlet tank coolant inlets of the second pair of radiators to engine.

22. A helical heat exchanger for cooling pressurized charge air from a turbo- or supercharger on the engine using liquid coolant from the engine, comprising:

a tube having first and second ends and a length therebetween, a plurality of coolant inlets for receiving liquid coolant from the engine, a coolant outlet for passing liquid coolant back to the engine, an inlet for receiving the pressurized charge air, and an outlet for passing cooled pressurized charge air back to the engine, the tube having an inner diameter;

a thermally conductive tube insert having an outer diameter substantially equal to the inner diameter of the tube, the tube insert having first and second ends and comprising a helix extending along the length of the tube insert and twisted around a central axis, the tube insert sealed within the tube by sealing an outer edge of the helix to an inner surface of the tube to form fluid-tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the tube;

a plurality of inflow openings to the tube insert first flow path, spaced along the tube length, in communication with the tube liquid coolant inlets, and a tube insert first flow path outflow opening in communication with the tube liquid coolant outlet; and an inflow opening to the tube insert second flow path in communication with the tube charge air inlet, and a tube insert second flow path outflow opening in communication with the tube charge air outlet, wherein liquid coolant may enter into the helical heat exchanger tube at different first flow path inflow openings and combine to pass through the tube insert first flow path and out the tube coolant outlet back to the engine such that the liquid coolant may absorb heat transferred through the thermally conductive tube insert from the charge air in the tube insert second flow path, and

wherein pressurized charge air may flow from the tube charge air inlet through the tube insert second flow path, transfer heat through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and pass out the tube charge air outlet back to the engine.

23. The helical heat exchanger of claim 22 wherein the helix has a predetermined pitch, the pitch of the helix defining a length of the first and second fluid flow paths within the helical heat exchanger, and wherein the pitch of the helix is constant along the length of the tube insert.

24. The helical heat exchanger of claim 22 wherein the helix has a predetermined pitch, the pitch of the helix defining a length of the first and second fluid flow paths within the helical heat exchanger, and wherein the pitch of the helix varies along the length of the tube insert from a minimum adjacent the first end of the tube to a maximum adjacent the second end of the tube.

25. A method of cooling pressurized charge air from a turbo- or supercharger on an engine, comprising:

providing a combination radiator and charge air cooler comprising: a core for cooling the liquid engine coolant, the core having a plurality of tubes each having an inlet end and an outlet end, and a plurality of fins in thermal contact with the tubes;

an inlet tank having a first end and a second end, and a coolant inlet for receiving the liquid coolant from the engine, the inlet tank being connected between the first and second ends to the inlet ends of the tubes of the core; and

an outlet tank having a first end and a second end, and having a first portion and a second portion between the first and second ends,

the outlet tank first portion being connected between the first and second ends to the outlet ends of the tubes of the core; the outlet tank having an opening between the outlet tank first portion and the outlet tank second portion; the outlet tank second portion having a coolant outlet, a charge air inlet, and a charge air outlet, the outlet tank second portion further having an inner diameter and a thermally conductive tube insert having an outer diameter substantially equal to the inner diameter of the second outlet tank portion, the tube insert having first and second ends and comprising a helix extending along a length of the tube insert and twisted around a central axis, the tube insert sealed within the outlet tank second portion by sealing an outer edge of the helix to an inner surface of the outlet tank second portion to form fluid- tight first and second fluid flow paths defined between opposing sides of the helix and the inner surface of the outlet tank second portion, respectively, the tube insert first flow path having an inflow opening in communication with the opening between the outlet tank first and second portions and an outflow opening in communication with the outlet tank second portion liquid coolant outlet, and the tube insert second flow path having an inflow opening in communication with the outlet tank second portion pressurized charge air inlet and an outflow opening in communication with the outlet tank second portion pressurized charge air outlet; passing liquid coolant from the engine through the inlet tank coolant inlet and the tubes through the core;

transferring heat from liquid coolant in the core tubes to air passing over the fins to cool the liquid coolant;

passing cooled liquid coolant from the core tubes through the outlet tank coolant outlet to the outlet tank first portion, through the opening to the outlet tank second portion and the tube insert first flow path inflow opening, and through the tube insert first flow path;

passing pressurized charge air from the a turbo- or supercharger on an engine through the charge air inlet of the outlet tank second portion, to the tube insert second flow path inflow opening, and through the tube insert second flow path;

transferring heat from the pressurized charge air in the tube insert second flow path through the thermal ly conductive tube insert to the liquid coolant in the tube insert first flow path, and absorbing the heat transferred from the charge air to the liquid coolant in the tube insert first flow path;

passing the liquid coolant out the outlet tank second portion coolant outlet back to the engine; and

passing cooled pressurized charge air out the outlet tank second portion charge air outlet back to the engine.

26. The method of claim 25 further including a thermally conductive common wal l separating the outlet tank first and second portions, wherein the opening between the outlet tank first portion and the outlet tank second portion is in the common wal l, and wherein the method further comprises:

transferring heat through the thermally conductive common wall between liquid coolant in the outlet tank first portion and liquid coolant in the tube insert first flow path in the outlet tank second portion, and between liquid coolant in the outlet tank first portion and pressurized charge air in the tube insert second flow path in the outlet tank second portion.

27. A method of cooling pressurized charge air from a turbo- or supercharger on an engine, comprising:

providing a helical heat exchanger for cooling pressurized charge air from a turbo-or supercharger on the engine using liquid coolant from the engine comprising:

a plurality of inflow openings to the tube insert first flow path, spaced along the tube length, in communication with the tube liquid coolant inlets, and a tube insert first flow path outflow opening in communication with the tube liquid coolant outlet; and an inflow opening to the tube insert second flow path in communication with the tube charge air inlet, and a tube insert second flow path outflow opening in communication with the tube charge air outlet,

flowing liquid coolant into the helical heat exchanger tube at different first flow path inflow openings along the tube length and combining the liquid coolant to flow through the tube insert first flow path;

flowing pressurized charge air through the tube charge air inlet into the tube insert second flow path;

transferring heat from the pressurized charge air in the tube insert second flow path through the thermally conductive tube insert to the liquid coolant in the tube insert first flow path, and absorbing the heat transferred from the charge air to the liquid coolant in the tube insert first flow path;

passing the liquid coolant out the tube coolant outlet back to the engine; and passing cooled pressurized charge air out the tube charge air outlet back to the engine.

28. The method of claim 27 wherein the helix has a predetermined pitch, the pitch of the helix defining a length of the first and second fluid flow paths within the helical heat exchanger, and wherein the pitch of the helix varies along the length of the tube insert from a minimum adjacent the first end of the tube to a maximum adjacent the second end of the tube; and

wherein the liquid coolant is flowed through the different first flow path inflow openings into the tube insert helix at different pitches of the helix.