Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0266—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P3/00—Liquid cooling
  • F01P3/20—Cooling circuits not specific to a single part of engine or machine
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
  • F28F21/06—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
  • G06F1/16—Constructional details or arrangements
  • G06F1/20—Cooling means
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
  • H01L23/427—Cooling by change of state, e.g. use of heat pipes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/46—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids
  • H01L23/473—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids by flowing liquids
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P5/00—Pumping cooling-air or liquid coolants
  • F01P5/10—Pumping liquid coolant; Arrangements of coolant pumps
  • F01P5/12—Pump-driving arrangements
  • F01P2005/125—Driving auxiliary pumps electrically
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P2050/00—Applications
  • F01P2050/30—Circuit boards
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P2060/00—Cooling circuits using auxiliaries
  • F01P2060/02—Intercooler
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
  • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
  • F28D2021/0028—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for cooling heat generating elements, e.g. for cooling electronic components or electric devices
  • F28D2021/0031—Radiators for recooling a coolant of cooling systems
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Definitions

• the invention relates to a major improvement made to cooling devices that operate by heat exchange between a hot liquid and a cold fluid.
• the invention relates to chillers performing a heat exchange water / air and, secondarily, to those whose hot liquid is different from water and / or those whose cold fluid is different from the air.
• Such cooling devices are associated with many organs to dissipate a specific heat flow which, for each member concerned, depends both on the total power implemented and the yield obtained.
• the thermal flows involved in the chillers according to the invention are located in two very wide ranges of power and temperature.
• the range of these powers ranges from about fifty watts to a hundred kilowatts.
• its lower limit is at least ten degrees higher than the maximum temperature of the cold fluid readily available and its upper limit, determined by the temperature of change of state of the hot liquid, to a possible pressure of use.
• Any cooling device associated with a member concerned, has a coupling surface adapted to marry, permanently or not, the heat dissipation surface of this body.
• the surfaces in question are the two faces of walls with a closed cross section, such as those of the cylinders of a heat engine.
• these surfaces are flat plates, small ( ⁇ 15 cm 2 ).
• averages ⁇ 2 dm 2
• high power or relatively large electronic equipment 5 to 20 dm 2
• Any water / air heat exchange cooling device coupled to the heat dissipation surface of a given organ, comprises:
• a boiler having an internal cavity, provided with two collectors, and a coupling surface, corresponding to said heat dissipation surface;
• a finned radiator provided with two collectors; ducts for connecting together the collectors of the boiler and the radiator and thus constitute a sealed enclosure;
• the radiator of such a cooling device As regards the radiator of such a cooling device, the requirement of having a high thermal conductance as well as a reduced frontal area and / or a limited volume is imposed on it in all cases.
• the overall performance of such a cooler is stated by a single value, that of its total thermal resistance, which is expressed in degrees per Watt (° / W) or its inverse, the thermal conductance (in Watts per degree).
• a heat exchanger water / air heat coupled to a microprocessor that must evacuate 100 Watts, while remaining at an average temperature of 60 ° C.
• This cooler comprises a mini-boiler in which the water enters at 50 0 C, leaves at 60 ° C and circulates at 2.4 g / s.
• the average temperature of the water in the mini boiler is 55 ° C and the difference between the average temperature of this water and that of the heat dissipation surface of the microprocessor is 5 ° C.
• the thermal resistance of the mini-boiler coupled to this surface is 0.05 ° / W.
• the air enters at 25 ° C in the radiator, leaves at 45 0 C and circulates at 5 g / s, while the average temperature of the water in the radiator is 55 ° C.
• the difference between the average temperatures of the water and the air in the radiator is 20 ° C., which gives 0.20 ° / W for the thermal resistance of the radiator.
• the total thermal resistance of the cooler device in question is 0.25 0 AV.
• mini-boilers waterblock, English trade
• pumps have some originality
• the radiators are all of a standard type with full metal fins.
• mini-boilers described are copper blocks, of a hundred cm 3 , machined to have an internal cavity provided with a generally welded metal cover and upstream and downstream connectors or collectors.
• Such an internal cavity is constituted either by a single channel, sinuous or spiral, relatively wide, equipped with connections, or by a small number of relatively narrow parallel channels, provided with collectors.
• Another example of a mini-micro-channel boiler is described in US Patent No. 5,263,251 of 1993.
• It is constituted by a block, equipped with two inlet and outlet tubes, which is the result of the rolling of a stacking many copper sheets, one side of which is etched, to reveal a fine rectilinear or sinuous passage between two openings. After laminating of the stack of sheets thus etched, these openings constitute the welded edges of the two internal collectors micro-channel supply resulting from the crushing of the material delimiting these passages. The heat dissipation surface of the microprocessor to be cooled is applied to a side wall of the block thus formed. This results in significant thermal resistance for such a mini boiler.
• the pumps used are generally pumps equipped with a brushless electric motor and a centrifugal turbine.
• the hydraulic power of these pumps is relatively high in order to be able to generate, in a single-channel mini-boiler and in the associated full-fin radiator, a water circulation in turbulent flow, which increases strongly (up to 20 times) the apparent thermal conductivity of the water flowing in these two components.
• a pump available on the market, which comprises a brushless electric motor 25 W, provided with a rotor consisting of a multipolar hemispherical magnet about 5 cm in diameter, integral with a turbine centrifugal, and which provides a hydraulic power of about 5 W, with a pressure of several hundred hectopascals.
• these pumps are too bulky for a small computer and, moreover, they are relatively expensive.
• thermal microprocessors usual, as being substantially uniform, thanks to the very good thermal conductivity of the dissipation plate, and generally between 5 and 15 W / cm 2 .
• this working hypothesis is generally verified for medium-performance microprocessors, it is no longer the case for very high performance microprocessors, currently or soon available on the market.
• These very high performance microprocessors in fact comprise, in the center of a usual heat dissipation plate of approximately 12 cm 2 , a small, very hot zone, generally rectangular, of approximately 1.5 cm 2 , through which the density of the heat flow, under extreme operating conditions, may be of the order of 140 W / cm 2 .
• Another technique of water cooling microprocessors uses a mini-boiler, consisting of several hundred micro-channels, arranged in a multilayer silicon wafer.
• a relatively powerful pump circulates water in laminar flow in these microchannels and turbulent flow in a standard finned radiator associated with a fan.
• This technique has the advantage of being able to correctly cool the hottest points of the organ concerned. This is of great interest. But it is obviously too expensive for many common applications, especially for PCs for the general public.
• Another microprocessor cooling technique makes use of one or more heat transfer tubes. These are copper tubes a few millimeters in diameter, provided throughout their length with an internal tubular wick.
• a mechanical pump quickly circulates, in a closed circuit, water in turbulent flow in the internal cavity of the boiler arranged around the engine cylinders, then in the hoses and the radiator. It comprises a small number of parallel metal tubes, on which are slid and welded or crimped metal fins, perforated for this purpose. Between these fins circulates a current of air generated by a fan and / or the relative wind of the vehicle.
• the flow of water may not be very turbulent and yet allow a good heat transfer, since the temperature difference is very important between the thermal dissipation surfaces of the engine and the coupling of the cooler.
• the internal face of the walls of the cylinders, in contact with the very hot burnt gases present at the end of each expansion, is at a very high temperature (> 600 ° C), while the outer face of these walls, in contact with flowing water, is at the temperature of this water (80 ° C).
• the thermal resistance of these walls is negligible, the water flowing in the boiler is subjected to all of this temperature difference. Under these conditions, the high thermal resistivity of a water in low turbulent flow, subjected to such a temperature difference, is a small obstacle to a fast and complete transfer of the thermal flow of the flue gases to the water current.
• the average difference in temperature between the water flowing in the radiator tubes and the air current flowing through its fins being relatively low (60 ° C.)
• the apparent thermal resistivity of this water be as small as possible so that the overall thermal conductance of this radiator is as large as possible, taking into account the value of this difference.
• the hydraulic diameter and the number of radiator tubes can not be very large, the only parameter available to make the flow of water in these tubes highly turbulent is its circulation speed, which must therefore be relatively high. This results in a significant pressure drop in the radiator, which has the consequence of imposing on the pump a relatively high hydraulic power.
• the current of air that sweeps the fins of the radiator can have only a limited fraction (about 30%) of the average temperature difference that it presents with the flow of water entering the radiator, to carry the heat flow to dissipate.
• the pump circulates this water at 2400 g / s, at an initial temperature of about 80 ° C, in a standard radiator having 5 dm 3 of volume, 17 dm 2 of frontal surface (master-torque) and 10 m 2 of fins.
• a standard radiator having 5 dm 3 of volume, 17 dm 2 of frontal surface (master-torque) and 10 m 2 of fins.
• the water loses 3 ° C approximately air flow of 2 kg / s (1.65 m 3 / s), which penetrates to 10 m / s between these hot fins, increases its temperature by 15 ° C, which passes for example from 25 to 40 ° C.
• the thermal resistance of this radiator with full metal fins is l, 8.10 ⁇ 3 ° / W and its volume conductance of 110 W / K.dm 3 .
• the above considerations can be explained immediately by the thermal conductivity of the materials concerned. Copper has a thermal conductivity of 380 W / mK, aluminum 220 W / mK and water of 0.6 to at least 12 W / mK, for a flow from laminar to turbulent.
• the thermal conductivity is particularly low: 0.22 W / mK
• the heat capacity of water it is 4.18 kilojoules per kilogram and per degree, while that of dry air is 1 kJ / kg / K.
• radiators with full metal fins associated with water / air heat exchanger chillers, intended for microprocessors and, more generally, any member provided with a plane heat dissipation surface.
• the average residual temperature difference existing between the outer faces of the fins and the air current that scans them is the sole and only engine of the desired cooling. It is therefore imperative to increase it at best.
• the first object of the invention is an improved, efficient, compact and inexpensive cooling device, which operates by heat exchange between a hot liquid and a cold fluid and which incorporates a finned radiator of a particular type, having a very low thermal resistance.
• the second object of the invention is such an improved cooler, wherein water flows in laminar flow in the radiator.
• the third object of the invention is such an improved cooler which incorporates an original mini-boiler, for body with flat heat dissipation surface, in which the water circulates in laminar flow in the mini-boiler and in the radiator.
• the fourth object of the invention is such an improved cooler for very high performance microprocessors, comprising a suitable mini-boiler, provided with a heating plate having a particularly low thermal resistance.
• the fifth object of the invention is such an improved cooler for very high performance microprocessors, comprising a suitable mini-pump, hydraulic power, pressure and flow, adapted to the limited needs of this cooler.
• the sixth object of the invention is such an improved cooler for very high performance microprocessors, comprising an original component, formed by the combination of such a suitable mini-boiler and such a suitable mini-pump.
• the seventh object of the invention is an efficient and inexpensive cooling device, for a heat engine or PEM type fuel cell, which comprises a finned radiator of particular type, in which the water circulates in laminar flow.
• the eighth object of the invention is a complementary cooling device for a diesel engine, intended to cool its exhaust gases to allow them to be used in order to improve the operation of this engine.
• an improved cooling device effective and inexpensive, operating by heat exchange between a hot liquid and a cold fluid, intended to be coupled to the heat dissipation surface of a given subject member, or coupled by construction at the same surface, said member having to dissipate a given heat flow, situated within certain power and temperature ranges, comprising:
• a boiler adapted to said heat flow comprising an internal cavity, provided with two collectors, and a coupling surface corresponding to said heat dissipation surface;
• a hot liquid, especially water, in this chamber means for circulating, in a closed circuit, this hot liquid in this chamber;
• means for circulating this cold fluid, in particular air, between the fins of the radiator is characterized in that
• said radiator is formed by one or more heat exchangers of a particular type, each consisting of a stack of hollow and thin fins connected to two transverse collectors.
• An active heat exchange element TET is a one-piece piece, without assembly or welding, formed by a stack of pairs of elongated thin hollow plates, constituting communicating hollow fins, generally symmetrical, and if necessary oblique, provided with two transverse collectors , extended by two connection pipes. This element is manufactured as follows:
• - (1) is carried out, by heat-blowing a suitable polymer or glass or hydroforming a metal of suitable nature and shape, a blank consisting of a stack of bellows generally biconvex, comparable to those of an accordion , having embossed walls and elongated central portions, provided with end connections, preferably with returnable surfaces, and two connecting pipes, centered on the stacking axes of the connectors;
• this blank being at the appropriate temperature, applying an internal negative pressure and / or external compression forces, parallel to the axis of stacking of its bellows, until the compressed part thus produced becomes a stack pairs of hollow fins, communicating and generally symmetrical, where appropriate bistable and oblique, internal thickness and small spacing, substantially constant;
• said means for circulating the hot liquid are adapted, on the one hand, to generate a laminar flow of this liquid in the hollow fins of the radiator as well as, where appropriate, in the internal cavity of the boiler and, secondly, to preferably circulate the liquid against the current of the cold fluid flowing between these fins.
• the thickness of their walls is approximately between 0.5 and 1 mm, and that of their internal channel, approximately between 0.5 and 2 , 5 mm;
• the thickness of their walls is approximately between 0.2 and 0.5 mm, and that of their internal channel, approximately between 0.5 and 1, 5 mm; - In all cases, the average gap between the fins is about 3 to 6 mm, when the cold fluid is air.
• the nominal flow rate of the water (it corresponds to the thermal power to be dissipated) in these fins is made in laminar flow and yet the efficiency of the radiator is very high.
• a flow is laminar when the number of Reynolds to be taken into account is low. And this number is proportional to the product of the hydraulic diameter of each of the hollow fins and the speed of circulation of the water flow concerned.
• the first term is weak, since it is substantially equal to twice the average internal thickness of a fin, and the second is equal to it, since it is equal to the nominal flow of water, corresponding to the heat flow to be evacuated, divided by the section large total of the stack of fins.
• the thermal resistivity to be taken into account is that of water without any corrective factor, but as the flowing water veins are thin, the total thermal conductance of the water stream is finally satisfactory. It is the same with the thermal conductance of the polymer walls of the fins which, too, have a high resistivity and a low thickness. Under these conditions, the temperature of the outer face of each fin is close to that of its internal face and it is the same at all levels, from its root to its end.
• the water / air coupling, carried out through the walls of the hollow and thin fins of a monoblock radiator is improved by the embossing of the walls (intended to give them an appropriate stiffness) which locally introduces slight reliefs and therefore some eddies in the flow of air, which increases the apparent conductivity of this air.
• the thermal / water heat exchanger cooling device of a heat engine is further characterized in that:
• the radiator comprises a group of heat exchangers with hollow and thin fins, mounted in parallel;
• This group of exchangers is supplied with water by a pump and air by a fan, so as to be traversed against the current by air and water.
• the radiator is split and formed by two groups of heat exchangers, mounted on the right and left of the engine.
• a cooler according to the invention for a motor vehicle engine equipped with a single or split radiator with hollow fins and thin, provides performance in various areas much higher than those provided by a cooler to standard radiator, associated with a motor of the same power. Indeed, in such a cooler, the master-torque of the radiator, the power of ventilation and water circulation, the weight and the price of all the components are greatly diminished, while the overall efficiency of the cooling is improved. It should be noted that all of the above-mentioned means and considerations apply without any noticeable change to the cooling of the bipolar plates of the PEM type fuel cells, which must operate at a temperature of approximately 85 ° C., with a yield approaching 50%. . When such a battery of a few tens of kilowatts must be installed on a motor vehicle, this implies the need for an effective cooler, compact and inexpensive, such as that according to the invention described above.
• a complementary cooling device for a diesel engine intended to produce cooled flue gases, that can be used to improve the operation of this type of engine, is further characterized in that:
• the boiler is a thin, hollow metal fin heat exchanger installed in a suitable chamber, arranged upstream of the usual expansion chamber of the exhaust gas exhaust pipe;
• the radiator is formed by several heat exchangers hollow fins and thin, metal or glass, mounted in parallel;
• a pump is adapted to circulate water in closed circuit and laminar flow in the sealed chamber formed by the boiler and the radiator;
• a fan is adapted to circulate air between the hollow fins of the radiator, against the current of the water flowing in these fins.
• the second heat exchanger fin and hollow fins no longer works as a radiator as in the previous case, but in boiler capturing the heat flow carried by the flue gases produced by the engine.
• these very hot gases > 600 ° C.
• these very hot gases are cooled under the same conditions as the engine cylinders and brought for example to 200 ° C. and then cooled again during their expansion before escaping.
• an appropriate fraction of these highly cooled gases can be removed and mixed with the air injected into the cylinders to improve the operation of the diesel engine at these speeds and thus suppress the production of effluents.
• Another diesel engine exhaust cooler is shown in European Patent Application No. 2002 195106, filed by the Japanese company Hino Motors.
• This cooler comprises a heat absorber (not described), installed in a pipe for discharging a portion of the flue gases, connected by a heat transfer tube to a device (not described) for the radiation dissipation of this heat, installed near the end of the exhaust pipe. It constitutes the technological background of the complementary cooler according to the present invention. According to the characteristics of other applications of the invention, in a cooler with a heat exchange between a hot liquid and a cold fluid, for members with rectified plane heat dissipation surface,
• the means for circulating the hot liquid, and in particular the water may be natural convection, when a suitable minimum vertical gap can be established between the upstream mouths of the mini-boiler and the radiator;
• said minimum vertical deviation is defined by the fact that it is capable of generating, by thermo-siphon, a nominal flow rate of the hot liquid which, on the one hand, corresponds to the heat flow to be dissipated in the installed radiator, swept by the air flow available and which, on the other hand, maintains the maximum temperature of this liquid below a determined ceiling, specific to the body concerned;
• the ducts of the internal cavity of the mini-boiler have, at nominal flow rate of the liquid, a low pressure drop, compatible with a sufficient minimum thermal conductance of this mini-boiler; - The upstream and downstream collectors of the mini-boiler and the connections connecting the latter to the radiator mouths have the lowest pressure drop possible;
• the hot liquid can then circulate either by simple expansion or mainly by producing a diphasic mixture of liquid and vapor bubbles.
• the appropriate minimum distance between the upstream mouths of the mini-boiler and the radiator is of the order of one decimetre
• the hot liquid circulating by natural convection is water at atmospheric pressure.
• a chiller operating by natural convection mainly due to a mixture of hot liquid and steam bubbles,
• the appropriate minimum gap between the upstream mouths of the mini-boiler and the radiator is of the order of one centimeter
• the hot liquid can undergo a change of liquid / vapor state, at a temperature at least a few degrees lower than the ceiling imposed on the member to be cooled;
• said hot liquid is preferably water under low pressure or, if appropriate, a liquid having said state change property at atmospheric pressure.
• the microprocessor heat dissipation plate a thin layer of high thermal conductivity paste, is applied to the rectified thermal dissipation plate, and then the ground thermal coupling surface of the mini-boiler.
• this mini boiler has a high thermal conductance, which will further be subject to additional considerations.
• the sealed chamber of the cooler contains a boiling liquid at a temperature a few degrees lower than the maximum temperature that can accept the microprocessor. Such a liquid operates at low pressure or at atmospheric pressure.
• the first case it will preferably be water (under 300 hPa, water boils at 60 ° C) and in the second, ether (30 ° C), methanol (60 ° C) , or ethanol (78 ° C), for example.
• a short vertical gap at least of the order of a centimeter, between the upstream mouths of the mini-boiler and the hollow fin radiator, allows, without using a pump, to perform a satisfactory flow dissipation.
• high heat emitted through the small heat dissipation plate of a microprocessor. This, thanks to the circulation by natural draft of a two-phase heat transfer mixture, formed by a liquid and by bubbles of its vapor.
• the latent heat of condensation released on this occasion is totally carried away by the air flow, thanks to the good thermal conductance of the thin stream of water circulating in the hollow fins of the radiator and the thinness of the walls of these fins.
• the average temperature of the mixture of water and vapor bubbles is 15 to 20 ° C higher than that of the air entering between the fins of the radiator. and the average density of this mixture is increased by about 20%.
• the air temperature has risen a lot and finally becomes only about ten degrees lower than the initial average temperature of the liquid-vapor mixture.
• the boiler is a mini-boiler, perfectly suitable for its function, which includes a heating plate, metal with high thermal conductivity, and a rigid hose molded polymer;
• the heating plate is provided with a corrugated external face for coupling, corresponding to said heat dissipation surface, and an initially flat internal face, the central part of which is hollowed out with parallel grooves of dimensions, pitch and number, determined by the density and intensity of the heat flux to be dissipated;
• the hose incorporates two upstream and downstream collectors, opening on either side of a flat rectangular central zone of its inner face;
• the heating plate is attached in a sealed manner to the inner face of the hose; said planar rectangular central zone of the hose is applied to the central part of the grooved internal face of the heating plate, so as to serve as a lid thereof and thus constitute the internal cavity of the mini-boiler and to disengage the mouths of this cavity.
• the member concerned is a microprocessor with very high performance
• the rectified heat dissipation plate has a small central zone very hot
• the width of the grooves of the heating plate is as small as possible, less than 0.2 mm, their depth is, in decreasing function, about ten to fifteen times this width, and their pitch of about two times ; the grooved central portion of the internal face of the heating plate extends well beyond said small, very hot central zone of the microprocessor; the thickness of the heating plate is approximately twice the depth of the grooves;
• a pump is used to circulate the hot liquid.
• the member concerned is a microprocessor with high or medium performance
• the rectified plate heat dissipation has a central zone a little warmer
• the width of the grooves of the heating plate is between approximately 0.5 and 1.5 mm, their depth, in decreasing function, of approximately five to eight times their width, and their pitch of approximately twice; the grooved central portion of the internal face of the heating plate extends well beyond the warmer central zone of the microprocessor;
• the thickness of the heating plate is about half the depth of the grooves
• the collectors of the mini-boiler are in alignment with the grooves of the heating plate
• thermosiphon can be used to circulate the hot liquid.
• this cavity is formed of micro or mini-channels, with a hydraulic diameter corresponding to that imposed by the maximum local density of the heat flow to be dissipated and by its total intensity.
• this hydraulic diameter is determined by the desired local nominal flow rate and the minimum required thermal conductance, which can be ensured just above said very hot or hot zone of the microprocessor.
• the laminar flow produced in these mini or micro-channels is done with a very low pressure drop.
• the grooves of the heating plate will be very fine and a pump will be used. When this intensity and density are lower, these same grooves will be wider and a thermosiphon can be used to circulate the hot liquid. In both cases, the thickness of the heating plate is determined, so that the effective diffusion of heat between the hot or hot central zone of the microprocessor dissipation plate and the entire surface of the microprocessor is properly ensured. the grooved central portion of the inner face of the heating plate.
• the section of the upstream and downstream collectors of the mini-boiler and that of their mouths must be at least equal to the total section of its mini-channels, the connecting bends between the ends of the micro-channels and the collectors should be as open as possible and the axes of these two collectors will be located on the same line as the central groove or fin of the heating plate. This, to avoid the presence of restrictions and elbows generating pressure losses that limit the flow of water.
• the axes of the upstream and downstream collectors of the mini-boiler will preferably be perpendicular to the grooves of the heating plate. Which in the case of a mini-boiler associated with a commercial pump can reduce its size.
• a water / air heat exchanger cooling device for a microprocessor, comprising a hollow and thin finned radiator, a suitable mini-pump and a mini-boiler, is characterized in that:
• this appropriate mini-pump comprises a brushless electric motor, provided with a rotor, in the form of a roller with a single diametrical magnetization, and a centrifugal turbine integral with this rotor;
• the body of this mini-pump comprises a cylindrical cavity, provided with a tight cover
• the rotor-turbine assembly is rotatably mounted on a pivoting shaft in two small bowls, arranged in the bottom of this cavity and in the inner face of the lid;
• the turbine is constituted by radial blades erected in a ring on a disc; - A water inlet duct is arranged in the lid and opens in the center of this ring;
• a water outlet opening is arranged in the wall of the cavity, at the blades of the turbine;
• two diametrically opposed portions of the wall of said cavity are thin-walled cylinder portions and the stator poles of the electric motor match these wall portions;
• the stator of the electric motor comprises a winding powered by an electronic circuit, adapted to start the engine and then rotate it to an appropriate speed. Thanks to these arrangements, it is possible to construct a suitable mini-pump, corresponding exactly to the very limited needs of a laminar flow water cooler, for a microprocessor. With a roller with a single diametrical magnetization, 3 cm diameter and 3 mm thick, the efficiency of such a brushless electric motor can approach 10% and the power consumption equal 2 W, safely.
• the well known technologies of the different types of brushless electric motors which may be used in the context of the present invention, will not be recalled here.
• the hydraulic power supplied can reach 100 mW (hydraulic pressure: 100 hPa, nominal flow rate of water 10 g / s) .
• the hose of the appropriate mini-boiler and the body of the appropriate mini-pump, described above are the two juxtaposed parts of the same molded rigid polymer block, so that this mini-boiler and this mini-pump together constitute an original component, in which the input of the upstream collector of the mini-boiler and the water outlet of the mini-pump are combined, the upstream collector of the mini-pump and the downstream collector.
• the mini-boiler are respectively the upstream and downstream collectors of this component and the latter two collectors are perpendicular to the grooves of the heating plate.
• a new, space-saving, lightweight and inexpensive component is created which can easily fit into the cooler of a small, portable or desktop computer.
• a component makes it possible to connect together the mini-pump and the mini-boiler, with a minimum risk of leaks and a minimum of pressure drops.
• FIG. 1 is a sectional view along the longitudinal plane of symmetry CC (see Figure 2) of a water cooler for medium performance microprocessor, wherein the water circulates by thermosiphon;
• - Figure 2 is a view along the section plane AA ', shown in Figure 1;
• - Figure 3 is a view along the section plane BB ', shown in Figure 1;
• FIG. 4 is a schematic view of an automobile diesel engine, equipped with a water cooler device according to the invention and a complementary device for cooling the flue gases;
• FIG. 5 is a schematic view of a water cooler for a microprocessor
• FIG. 6 is a longitudinal sectional view of an original component, comprising a mini-boiler and a mini-pump, of such a water cooler, for a very high performance microprocessor
• - Figure 7 is a top view of this component.
• a cooling device 10 is installed vertically. It is coupled and fixed, by any appropriate means, to a microprocessor 12, capable of generating a thermal power of 120 Watts. This heat flow must be discharged through a corrected square plate heat dissipation 14, 35 mm side (an average density of 10 W / cm), so that its average temperature remains below 70 ° C, for example .
• the cooler 10 comprises a mini-boiler 16, a rigid hose 18, a radiator 20, an envelope 22 and a fan 24.
• the mini-boiler 16 is formed by a copper heating plate 17 applied on the hose 18.
• heating plate 17 to 10 mm in total thickness and it has an outer face of thermal coupling 26, square and rectified, 35 mm side, connected by two ramps to its fastening edges 28-30, 10 mm wide, as well as a thick bottom of 2 mm and side walls of 1 mm.
• the inner face 31 of this heating plate 17 has eleven parallel grooves 32 ⁇ 11 , 1.5 mm wide, 40 mm long and 8 mm high, in their central part, and ten fins 34i.i 0 of 1 mm thick.
• the ends of these fins 34 and these grooves 32 have profiles in arcs and the distance between their extreme edges is 60 mm.
• the external coupling face 26 of the heating plate 17 matches the dissipation plate 14 of the microprocessor, through a thin layer of high thermal conductivity paste (not shown).
• the edges 28-30 of the heating plate 17 are applied and fixed by screws, in a sealed manner (flexible seal) on the hose 18.
• This hose 18 is rigid polymer and its central portion 36 has a hollow outer face and a rectangular internal face 35, 30 mm long and 27 mm wide, adapted to bear on the tops of the fins 34i -] 0 and the two lateral edges of the plate 17.
• this inner face 35 of the hose 18 constitutes the lid of the central portions of the grooves 32i. ⁇ and delimits, just above the curved bottoms of these grooves, the substantially rectangular mouths, downstream 38 and upstream 40, of the mini-boiler 16.
• the upstream collectors 42 and downstream 44 of the mini-boiler 16 are connected to these mouths.
• the section of these mouthpieces is at least equal to the total section of the mini-channels, formed by these grooves and their cover, which together constitute the int cavity
• the upstream manifold 42 is a short conduit 2.5 cm long, having a circular inlet mouth 50, connected to the downstream pipe 46 of the radiator 20, and a rectangular outlet mouth 40.
• the collector 44 is a 7 cm long conduit, having a rectangular internal mouth 38, connected downstream of the grooves 32j.ii, and another circular external 52, connected to the upstream mouth 48 of the radiator 20.
• the vertical distance between the axes of the upstream mouths 40 and 48 of the mini-boiler 16 and the radiator 20 is 12 cm.
• the mini-boiler 16 and its two collectors 42-44 have the same plane of symmetry, which runs along the central groove 32 6 of the inner face 31 of the heating plate 17.
• the collectors 42-44 are connected to the tubes 46- 48 of the radiator 20, by horizontal ducts as short as possible (not shown).
• the upper end 53 of the hose 18 comprises a boss 57, provided with a small opening intended to allow the filling of the enclosure and then to be sealed.
• the external mouths 50-52 of the collectors 42-44, their possible connection ducts and the tubes 46-48 of the radiator 20, are connected to each other by any appropriate means, in particular collars, collages or welds.
• the radiator 20 is a one-piece heat exchange element with hollow fins and thin, high density polyethylene, optionally loaded with carbon. It is shown with eight pairs of hollow fins 56 separated by spaces 58. In fact, the radiator 20 comprises fifteen pairs of fins, to be able to easily evacuate 120 W. These fins represented oblique result from a reversal of one biconvex bellows flanks of the initial draft and in fig.3, they all have the appearance of a fish spine.
• These fifteen pairs of fins have a total height of 17 cm, a gap of 12 cm between the axes of their tubings 46-48, a width of 5 cm and a total thickness of 9 cm, with a stacking pitch of 6 mm, walls of 0.5 mm on average, average internal thicknesses of 1 mm for the channels of the hollow fins and 4 mm for their separation spaces 58.
• the volume of this radiator 20 is about 0.7 dm 3 . It will be noted that the polyethylene HD loaded with a suitable additive becomes, in the extruder used to manufacture the blank of this radiator, a particularly fluid paste which makes it possible to obtain a great fineness of walls.
• the two hollow fins 56i -2 of a pair are connected to each other by a wafer of the central channel 60 of the monoblock element 20.
• the ends of this central channel 60 constitute, for the fins 56, two transverse collectors 62-64, extended by tubings 46-48.
• the sealed chamber in the form of a looped circuit, constituted by the mini-boiler 16, the conduits 42-44 of the hose 18 and the radiator 20, contains distilled water at atmospheric pressure. This water is introduced into this chamber through the opening of the boss 57, its final level corresponding approximately to the axis 49 of the upper pipe 48 connecting the radiator 20.
• the envelope 22 may be formed by two shells, at the edges fixed to each other by any appropriate means (see the PCT application concerned). An opening is made in each of these shells, to allow passage and serve as a fixed support for the two connecting pipes 46-48 of the boiler 20.
• the walls of the casing 22 are close to the ends of the hollow fins 56 of the radiator 20 and its mouths 66-67 are wide.
• a crown 68 which serves to support the mounting arms (not shown) of the fan 24 equipped with a propeller 25.
• This fan 24 is adapted to produce an air flow of at least 10 liters / second.
• the effective heat exchange surface between the heat dissipation plate 14 of the microprocessor 12 and the water contained in the numerous channels 32 of this mini-heater 16 boiler 16 is in practice multiplied by six.
• the heat flow to be dissipated 120 W
• the difference between the average temperatures of the dissipation plate 14 and the water in the mini ⁇ boiler 16 is about 6 ° C, for the heating plate 17, a thermal resistance of 0.05 ° / W.
• the expansion of the water due to its rise in temperature generates between the upstream mouths 40-48 of the mini-boiler 16 and the radiator 20, a natural convection push, which circulates the water with a flow rate a little less than 3 g / s, directly determined by the total pressure drop in the closed circuit of the cooling device 10. While passing through the radiator with hollow fins 20, the pressure drop of the water flow is limited to a few Pascals and its temperature passes from 60 to 50 ° C, which corresponds to the desired evacuation of the 120 W to be dissipated.
• the ambient air flow enters at 35 ° C in the envelope 22 and it leaves at 45 ° C, which corresponds to an air flow of 12 g / s (or 10 liters per second). at 35 ° C) between the hollow fins of a radiator 20.
• the water enters at 50 0 C in the boiler 16 and leaves at 60 ° C, which has the effect of maintaining the temperature of the upper edge of the plate heat dissipation 14 of the microprocessor 12 to a maximum value of 66 ° C, given the thermal resistance between the plate 14 and the water that must cool it.
• the total thermal resistance of such a radiator 20, traversed countercurrently by water, at an average temperature of 55 ° C., and by air at an average temperature of 40 ° C., is 0.125 ° C. / W.
• the total thermal resistance of the cooling device according to FIG. 1, in which the water circulates without a pump by natural convection alone, is therefore 0.175 ° / W.
• the radiator 20 and its envelope 22, equipped with a fan 24-25 can be installed inside the apparatus and, in this case, the air enters there warm (40 °).
• the air can be directly drawn outside the apparatus, at a temperature of 25 ° C for example, which decreases the total thermal resistance of the cooler without modification of the radiator 20.
• Another variant consists in arranging the radiator 20 outside the appliance and installing it in a duct of appropriate height, operating in a chimney (> 15 cm).
• the outside air enters from below and climbs by natural convection, assisted or not by a low power fan.
• the air flow sweeping the fins is thus reduced, it will have to be compensated by an increase in the number and / or the length of fins of the radiator, in proportion to the factor of reduction of this flow.
• Such an arrangement is suitable for economical cooling of high power electronic circuits.
• the radiator 20 will be made of a metal or a suitable polymer, so as to be substantially more rigid than the thin-walled one described above. Water will be introduced, under vacuum of air or dilated at 100 ° C and atmospheric pressure, in the enclosure of the cooler 10, then the enclosure will be immediately sealed.
• the flow of the water-bubble mixture produced can reach less than that of the liquid water previously obtained with a radiator having about 12 cm of difference between the axes of the upstream mouths 40-48.
• the initial and final temperatures of the water and air specified above will hardly be modified for an identical heat flow.
• the radiator 20 can be installed inside or outside the device.
• a diesel engine 70 developing 30 kW of mechanical power is installed on a motor vehicle 72 and is equipped with a split cooling device, which comprises two identical sets 74 ab installed to the right and left of the engine. 70.
• Each cooler 74 ab comprises a group 76 ab of five one-piece heat exchangers, with twelve pairs of hollow and thin polypropylene fins, mounted in parallel.
• the fins of these exchangers have 1 mm internal thickness, 0.5 mm wall thickness, 3 mm gap and 15 cm depth and each exchanger has a front surface of 5 cm wide and 6 cm long .
• the total frontal area of the ten heat exchangers is 6 dm 2 and their total volume is 9 dm 3 .
• Each group 76 ab has upstream collectors 75 ab and downstream 77 ab and is fed by a pump 78 ab, connected to the two end branches 80 ab of the downstream hose of the engine 70.
• the cooling water leaves at 80 ° C. the casing of the cylinders of the engine 70 and its flow rate is 1, 5 dm 3 / s.
• a single pump can be installed upstream branches 80 ab.
• the water takes one of the two branches 82 ab of the upstream hose of the engine 70, to return cooled to 75 ° C in the cylinder shell of the engine.
• the boiler of a complementary cooler device 88 intended to cool the flue gases produced by the diesel engine 70 is constituted by a monobloc heat exchanger 90, with hollow and thin metal fins, of appropriate size and shape.
• This boiler 90 is installed in a cooling chamber 92, inserted in the exhaust pipe 94 of the engine 70 and disposed upstream of the usual expansion chamber 96 included in such a pipe.
• the boiler 90 is connected to a radiator 98 formed by a group of heat exchangers, with hollow and thin metallic fins, connected in parallel, downstream of a fan 100.
• a pump 102 circulates water in overpressure in the enclosure formed by the boiler 90 and the radiator 98, co-current of the burnt gases leaving the engine 70 for the boiler 90 and against the current of the air blown by the fan 100 for the radiator 98.
• downstream of the expansion chamber 96 is installed a bypass valve 104 with two outlets 106 and 108, the first to a conduit 110 returning to the diesel engine 70 and the second outward.
• the bypass valve 104 operates in response to appropriate electrical control, adapted to direct a more or less significant fraction of the flue gas flow to one or the other of these two outputs 106-108.
• This appropriate electrical control reaches the valve 104 via a link 112 and is developed by a digital calculation circuit 114, programmed for this purpose, which receives from the diesel engine 70, via a link 116, a signal representative of the engine speed. .
• the window 118 symbolizes the openings for evacuating the air blown in the same direction by the fans 86 ab and 100 and then heated by the radiators 76 ab and 98.
• the cooling device 74 ab equipped with a thin and hollow fin radiator according to the invention, associated with the motor 70 of a motor vehicle 72, makes it possible to obtain much more interesting results in all respects than with a cooling device equipped with a standard radiator with full metal fins.
• a cooling device equipped with a standard radiator with full metal fins In the case of a motor with a heat engine (diesel or petrol), the water circulates in the casing of the engine cylinders, in a low turbulence flow sufficient to carry a heat flow at more than 600 ° C., substantially equal to the mechanical power generated. Then, it flows in laminar flow in the hollow fins of the split radiator 76 ab.
• the average temperature of the water must be between 80 and 90 0 C, depending on the instantaneous power demand of the engine and the ambient air temperature.
• the cooling device 74 ab according to the invention, the engine 70 of 30 kW, dissipates in the outside air a heat flow of the same value, with a water flow of 1.5 dm 3 / s and a permanent difference of 55 ° C between the average temperatures of the water and the air. This is achieved with a split radiator having the same total heat resistance of 1.8 ⁇ 10 -3 ° / W as with the full finned radiator referred to above, but with a total fin area reduced to 3.7 m 2.
• radiator depending on the thermal power to be dissipated in an air at a given temperature. From the front surface thus determined for the radiator with hollow fins to be used, these numbers are deduced from the number and pitch of these fins and then from their width and their wall and internal channel thicknesses.
• the dissipation of significant thermal flows (up to at least 100 kW) produced by the heat engines can be obtained by playing more or less on the total volume of the radiator and on the parameters relating to the fins, listed above. This will depend, in particular, on the maximum permissible frontal area, the hydraulic power of the pump, the aerodynamic power required at low speeds in climbs, or the maximum allowable increase in air temperature at the exit of the pump. radiator. Under these conditions, a cooling device according to the invention can be realized, so as to perfectly meet all the specifications decided by the design engineers of new motor vehicles. The cost of such a single or split radiator made of suitable polymer is significantly lower than that of an equivalent standard radiator.
• the thickness of a radiator with hollow fins is several times that of a radiator with full fins, since it is determined by the length of these fins, this poses no particular problem since it has usually a large space behind the radiators. This justifies the small importance of the relative decrease in the volume conductance of the new radiator.
• the suitable polymer to be used for manufacturing the radiator may be polypropylene or high density polyethylene, both inexpensive products. The use of a split radiator instead of just one is, for its part, justified by the fact that it provides a certain safety in case of accident and generally facilitates the optimal implementation of these annexes of the engine.
• Such a stack comprises a stack of cells which are each formed by a proton-conducting polymer membrane (in particular that sold under the brand Nafion by Dupont de Nemours) and an oxidation catalyst film (platinum), sandwiched between two permeable electrodes. . Between two electrodes of opposite signs belonging to two neighboring cells, is disposed a bipolar plate, with high electrical and thermal conductivities, provided with grooved faces.
• These grooves are conduits for supplying hydrogen to the anode of the membrane of a given cell, supplying air to the cathode of the membrane of a contiguous cell and evacuating the vapor from the cell. produced water.
• their middle part is crossed by numerous parallel mini-channels, intended to be traversed by the cooling water of the cell.
• they are often made of a good conductor material easy machining, graphite, for example.
• the membrane operates at a maximum temperature between 80 and 85 ° C, with an average yield close to 50%. This again entails the obligation to have an acceptable efficient cooling device.
• Each cell generates a voltage of about 0.8 volts and an electric power of at most 0.4 W / cm 2 , with a surface area of 25 dm 2 , a power of the order of one kilowatt. Under these conditions, the thermal flux density to be removed by the heat dissipation zone of each bipolar plate is about 0.4 W / cm 2 , which is very low.
• the thermal resistance per square centimeter interposed between the faces of the membrane generating electricity and the water flowing through the mini cooling channels is relatively high. This is the consequence of inevitably weak thermal couplings that exist between the faces of this membrane, the permeable electrodes (fine grids) and the bipolar plates with grooved faces of each cell.
• the thermal resistance of the mini-boiler, thus formed in the bipolar plate associated with the membrane generates whatever the surface of this plate a mean temperature difference of about 5 ° C, between the cathode of this membrane and the water flowing through the mini-cooling channels.
• the maximum temperature of this water at the outlet of the mini-channels is at most 80 ° C.
• a PEM type fuel cell 30 kW at 50 V, constitutes a block of about 40 dm 3 , formed by a stack of sixty four cells having faces of 4 x 3 dm 2 and a thickness of 5 mm.
• the flow rate of the water must be 720 g / s.
• an air flow of 0.75 kg / s which will heat up 40 0 C, during his crossing.
• the air outlet temperature will be 65 ° C and the average temperature difference between water and air of 30 ° C.
• the thermal resistance of the radiator should accordingly be 10 "3 o / W.
• Such thermal resistance is obtained by means of two groups of heat exchangers with hollow fins three times larger than the two groups 76 ab, used for cooling a heat engine 70 of the same power.
• the front surfaces of each group will be 9 dm 2 and the total surfaces of its fins 5.6 dm 2 . This is quite remarkable when compared to that of a single standard radiator with full fins (17 dm 2 ), commonly used to evacuate the heat flow of a 30 kW heat engine and, on the other hand, to that three times higher (51 dm 2 ) of the standard single radiator, which should be used to cool a 30 kW PEM cell.
• the maximum ventilation power required (fan and relative wind), it will be about 1 kW, or 3% of the useful power.
• the speed of the water in each is very low. This leads to its circulation in laminar flow in these mini-channels as well as in the hollow fins of the radiator.
• the power of each of the two pumps will be relatively low (of the order of 5 W hydraulic or about 20 Watts mechanical), the total pressure drop in the mini-channels of the bipolar plates of the battery and in the hollow fins radiator each being at most twenty hectopascals.
• the cooling device according to the invention associated with a fuel cell type PEM, installed on a motor vehicle can solve, under interesting technical and economic conditions, the problem posed by the dissipation of a very high heat flow, produced at low temperature and transferred to a circulating stream of water with a capped flow rate.
• the heat exchangers 90 with hollow metal fins no longer function as radiators as in the previous case, but in a boiler that captures the heat flow carried by the engine's flue gases.
• the concept implemented in the present case is in fact the symmetrical of that exploited in the previous case. With such metal heat exchangers, efficient, inexpensive and compact, such an installation becomes technically and economically feasible.
• a heat exchanger with hollow and thin metal fins, can perfectly withstand the high temperature of the flue gases of the engine (> 600 ° C). These gases enter the exhaust pipe 94 and they can, initially, be cooled in the chamber 92 to a relatively low temperature, for example 200 ° C with water under pressure and the metal radiator 98. In the hollow fins of the boiler 90 and between these fins, the water and the flue gases circulate in the same direction and in the radiator 98, water and air circulate in countercurrent. This, to simplify the implementation of the components concerned. In a second step, these gases are expanded in the expansion chamber 96 and, during this operation, they are cooled again to a temperature significantly lower than that of the ambient air.
• An appropriate fraction of these highly cooled burned gases is selected by the bypass valve 104 which operates under the action of a control signal developed by the calculation circuit 114, from a signal representative of the engine speed.
• this fraction of cold burned gases returns to the diesel engine 70 to be mixed with the air injected into the cylinders.
• the proportion of oxygen contained in the mixture can be easily brought, at low and medium engine speeds, to a sufficiently low value, which corresponds to stoichiometric proportions of diesel and oxygen-depleted air. This then prevents any production of highly polluting nitrogen oxides (NO x ) and allows, for the first time, to achieve in good conditions the wish long expressed by many engineers specialized in the diesel engine.
• NO x highly polluting nitrogen oxides
• a cooling device 110 with laminar flow water, for a microprocessor, comprises a radiator 112, with hollow and thin fins made of suitable polymer, polypropylene for example, provided with transverse collectors 113-115, directly connected to the collectors of an original component 114, formed by a mini ⁇ boiler 1 16 and a mini-pump 1 18.
• the component 114 (shown transparent for the purposes of the description) comprises a molded rigid polymer block 120, of approximately rectangular shape of 80 ⁇ 40 mm 2 and 10 mm of average thickness.
• This block 120 comprises the hose 119 of the mini-boiler 116 and the body 117 of the mini-pump 118, in which are arranged two cavities 122 and 124 respectively assigned to these bodies 118 and 116.
• These cavities 122 and 124 are cylindrical and have respectively for diameters and depths 31 and 8 mm for the first and 30 and 2 mm for the second.
• the cavity 122 is provided with a cover 126, adapted to be applied in a sealed manner on the block 120 and fixed to it, by means of four screws such as 128 and an O-ring (not shown).
• a roller 130 In the cavity 122 of the body 117 is installed, with a small clearance, a roller 130, with a single diametrical magnetization, 30 mm in diameter and 3 mm thick, which constitutes the rotor of a brushless electric motor 132.
• the upper face of this roller 130 is fixed a centrifugal turbine 134, molded polymer, comprising eight radial blades 136 of 10 mm long and 3 mm high, erected in a ring on a disc 138, glued on the roller 130.
• roller 130 and the turbine 134 are integral with an axis 140, pivotally mounted between two cups 142-144, arranged in the bottom of the cavity 122 and in the inner face of the lid 126.
• a flat duct 146 10 mm wide and 3 mm thick, connected to the upstream collector 148 of the composite device 114, which ends in a semicircle and opens above the clear center 150 of the centrifugal turbine 134.
• the electric motor 132 comprises a stator 152, constituted by two pieces flat plates of soft iron 154 ab, L-shaped, engaged in a flattened winding 156.
• the poles AB of the magnetic circuit 154 ab of the stator 152 have the shape of circular arcs of 90 °, which face two thin parts 121 90-124 of diametrically opposed diameters of the cylindrical wall of the cavity 122 enclosing the rotor 130. These two thin portions 121-123 constitute fractions of the air gaps of the magnetic circuit of the motor 132.
• the winding 156 of the electric motor 132 is powered. by an electronic circuit 158, of known type, associated with a detector 160 of the angular position of the rotor 130.
• the heating plate 162 of a mini-boiler 116 which plate is a copper disk 30 mm in diameter and 2 mm thick.
• the outer face 161 of this disc is ground and the central portion of its inner face 163, hollow micro-grooves 164 of 0.1 mm wide, 0.2 mm pitch, separated by fins, 1 mm high. .
• the portion 166 of the hose 119 is traversed by two oblique ducts 168-170, 2 mm thick and 20 mm wide, constituting the upstream and downstream collectors of the mini-boiler 116.
• the conduit 168 communicates with the cavity 122, at the blades 136 of the turbine 134, then it opens at 169, above the last two millimeters of the upstream ends of the micro-grooves 164.
• the conduit 170 begins in 171, above the last two millimeters of downstream ends of these micro-grooves 164, and it joins the downstream collector 174 of the composite device 114.
• a rectangular planar face 176 which constitutes the cover of the central portion of micro-grooves 164 and transforms them into micro-channels forming the internal cavity of the mini-boiler 116.
• the combination, in a single component, of the appropriate mini-pump and mini-boiler, according to the invention, is not the only way to use these two conjugated bodies of a water cooler in laminar flow.
• the heating plate 162 and the mini-boiler 116 are both new industrial products which, a priori, can not be manufactured, and where appropriate marketed alone, only to be part of a water cooler in laminar flow, according to the invention. It is the same for the new component 1 14 comprising a mini-boiler 1 16 and a mini-pump 118.
• a heating plate such a mini-boiler boiler and such a component form an integral part of the present invention.
• the mini-pump 118 its possible uses can obviously overflow the field of cooling devices, by heat exchange between a hot liquid and a cold fluid, for which it was developed.
• the invention is not limited to the case of motor vehicles equipped with these engines or of these batteries, since these engines and these batteries can obviously be used at fixed stations for all types of vehicles. kinds of applications.
• the invention is not limited to heat exchanges water / air. Indeed, for the cooling of marine engines, it is common to use a suitable heat exchanger, to maintain the primary cooling water of the engine at about 80 ° C and to heat sea water which is pumped cold and then evacuated warm, safe and perfect efficiency.
• the adaptation of a chiller according to the invention to the case of a marine engine is therefore simply to replace the fan adapted to blow air between the hollow fins of heat exchangers operating in a radiator, by a pump adapted to make circulate seawater in an envelope surrounding these exchangers.
• a similar provision can be implemented to achieve a co-generation of electricity and hot water .
• a cooling device for a heat engine is not limited to the use of water whose temperature range is between 60 and 90 ° C. Indeed, for very powerful heat engines (> 100 kW), the temperature of this water can be between 1 10 and 180 ° C with overpressures of 3 or 4 bars (case of engines of Formula 1).
• the monobloc heat exchangers used will be made of metal or glass and adapted to the high pressures used. In this case, an efficient cooler will be necessary for the engine oil and the hot liquid will be this oil, the cold fluid is always air.
• the improved cooling device can also relate to certain particular high-tech devices which, on the one hand, must operate at a determined setpoint temperature, of strongly negative value, and which, on the other hand, are subject to the disturbing action of any internal or external hot spring.
• the "hot" liquid will be for example alcohol and the cold fluid, a gas or a liquid of the trade, whose temperature at its operating pressure is significantly lower than the set temperature of the organs concerned.

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• 2005
  • 2005-06-23 US US11/571,210 patent/US20070184320A1/en not_active Abandoned
  • 2005-06-23 WO PCT/FR2005/001586 patent/WO2006010822A2/fr active Application Filing
  • 2005-06-23 EP EP05778868A patent/EP1766682A2/de not_active Withdrawn

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