EP0501854A1 - Motor vehicle radiator with fluid circulation control device - Google Patents

Abstract

Cooling radiator of the internal combustion engine of a motor vehicle, comprising two movable shut-offs (15, 16) associated with the same fluid box (1) and driven by the same actuator (17) as a function of the temperature of the engine. A first shut-off (16) closes the inlet to the fluid box in order to prevent any circulation in the radiator when the engine is cold. The second shut-off (15) controls an opening (5) in an intermediate partition (4) of the fluid box so that a variable fraction (f3) of the flow rate of fluid in the radiator, when the first shut-off is opened, is deviated via this opening (5) and does not pass into the tubes (10, 11) of the radiator. <??>This radiator fulfils the function of a heat switch, and further ensures regulation of its own efficiency as a function of the load of the engine. <IMAGE>

Description

The invention relates to a radiator for cooling the heat engine of a motor vehicle, provided with a device for controlling the circulation of the coolant.

FR-A-2 481 791 describes such a radiator, comprising a fluid box provided with an inlet or outlet pipe for a cooling fluid, and a bundle of tubes, the ends of which open into said fluid box, thus a partition provided with an opening dividing the fluid box into a first chamber into which the inlet or outlet tubing opens and a first subset of the ends of the tubes, and into a second chamber into which the complementary sub-assembly of the ends of the tubes, and a first shutter for the opening of the partition, movable under the effect of an actuator between an open position for which the fluid entering the fluid box through the tubing d entry or exit through the outlet tubing can pass directly from the first chamber to the second or vice versa and a closed position for which this fluid necessarily passes through the tubes to which belongs the ends of the first subset.

In this known radiator, the circulation control device formed by the first shutter and the actuator plays the role of the traditional calorstat, which is usually placed outside the radiator. Its effect is to suppress the circulation of the fluid in all or part of the radiator tubes, when the engine is cold, and to establish normal circulation in all of the tubes as soon as the engine has warmed up sufficiently, after a certain operating time.

To optimize the efficiency of the engine, it is desirable to operate it at constant temperature, which requires varying the efficiency of its cooling as a function of the calorific power which it releases and consequently of its load. To vary the cooling efficiency and thus regulate the engine temperature, it is possible to act on various parameters, and in particular on the flow rate of the fluid passing through the radiator tubes. To this end, it is known to have in series with the radiator a flow control valve controlled by a coolant temperature sensor placed at the outlet of the engine. The use of such an adjustment valve complicates the production of the cooling circuit. In addition, the rotary valves usually used do not provide a sufficiently gradual adjustment for low flow rates.

The object of the invention is to improve the radiator defined in the introduction so that it itself regulates the fluid flow in the tubes, making it unnecessary to mount an adjustment valve in series with the radiator.

For this purpose, the radiator according to the invention further comprises a second movable shutter, under the effect of the same actuator as the first shutter, between an open position and a closed position of the communication between the inlet pipe. or outlet and the first chamber, the actuator being able to pass from a first state in which the second shutter is in the closed position, preventing any circulation of the fluid in the radiator, to a second state in which the second shutter is in position opening and the first shutter is in a first of said opening and closing positions, forcing the fluid which passes into the first chamber to circulate in all the tubes of the radiator, and vice versa, passing through an intermediate state in which the second shutter is in the open position and the first shutter is in the second of said positions, allowing the fluid to circulate only in a part of the tubes, or only a part of the fluid to circulate in the tubes.

According to one embodiment of the invention, the two shutters are rigidly linked to each other, and are driven jointly by the actuator.

The two shutters can then come into the closed position respectively for the two ends of the actuator stroke, and both be in the open position for the middle part of the stroke.

A circulation control device operating in this way is suitable for a radiator with a U-shaped circulation configuration, the inlet and outlet of the fluid being carried out by the two chambers of the fluid box respectively, and the opening of the partition forming a bypass fluid passage with respect to all of the tubes.

It is also suitable for a radiator with a "Z" circulation configuration comprising a fluid counter box situated opposite the fluid box with respect to the tube bundle and divided by a partition into a first chamber into which opens a fluid outlet pipe (or inlet) and in a second chamber, a first sub-assembly of the tubes connecting the first chamber of the fluid box and the second chamber of the fluid counter-box, a second sub-assembly tubes connecting the second chamber of the fluid box and the first chamber the fluid counter box and the rest of the tubes connecting the second chambers of the fluid box and the counter box fluid, the opening of the bulkhead of the fluid box forming a bypass fluid passage relative to the first sub-assembly and to the rest of the tubes.

The term "fluid counter box" quite simply designates a second fluid box and is used to distinguish it from the first fluid box equipped with the circulation control device. In the case where the inlet pipe opens into the fluid box, the outlet pipe opens into the fluid counter box, and vice versa.

According to a second embodiment of the invention, the first shutter is linked to the second shutter so as to remain stationary, preferably in the closed position, over part of the travel of the second shutter adjacent to the closed position of this last, and to be united for the rest of its race.

This type of control device is suitable for a radiator with an "I" circulation configuration, which includes a fluid counter-box without partition into which opens a fluid outlet (or inlet) pipe and connected to the box. fluid through all of the tubes, the closing of the bulkhead of the fluid box preventing the fluid from passing into the second chamber thereof and into the tubes which emerge therein.

• les figures 1 à 3 représentent schématiquement un premier exemple de réalisation d'un radiateur selon l'invention, respectivement dans trois états différents ;
• les figures 4 à 6 sont des vues analogues aux figures 1 à 3, relatives à un second exemple ; et
• les figures 7 à 9 sont des vues analogues aux figures 1 à 3, relatives à un troisième exemple.

Other characteristics and advantages of the invention will emerge from the description given below of a few embodiments, and from the appended drawings in which:

• Figures 1 to 3 schematically show a first embodiment of a radiator according to the invention, respectively in three different states;
• Figures 4 to 6 are views similar to Figures 1 to 3, relating to a second example; and
• Figures 7 to 9 are views similar to Figures 1 to 3, relating to a third example.

The cooling radiator illustrated in FIGS. 1 to 3 comprises two fluid boxes 1 and 2 between which extends a bundle 3 of parallel tubes not shown individually, the two open ends of each tube opening respectively into the fluid box 1 and into the fluid box 2. A transverse partition 4 provided with an opening 5 divides the interior of the fluid box 1 into a chamber 6 in which the cooling fluid can enter the radiator through an inlet pipe 7 and a chamber 8 communicating with a fluid outlet pipe 9. A first sub-assembly 10 of the tubes of the bundle 3 opens into the chamber 6 and the complementary sub-assembly 11 opens into the chamber 8, these two sub-assemblies being delimited schematically by a dashed line 12.

A second partition 13 provided with an opening 14 separates the chamber 6 and the inlet pipe 7. The opening 5 of the partition 4 and the opening 14 of the partition 13 can be closed respectively by shutters 15 and 16 driven jointly by an actuator 17 via a rod 18 on which they are mounted integrally. The specific characteristics of the actuator 17 do not form part of the invention. It can include a substance with a high coefficient of thermal expansion such as a wax, the volume changes of which cause the movement of the rod 18. This substance can be heated directly by the coolant leaving the vehicle's heat engine, and / or by an electric current controlled according to appropriate parameters relating to the engine operation. The actuator can also use a memory alloy, or an electric motor.

In the position illustrated in Figure 1, the shutter 16 closes the opening 14, and the coolant cannot enter the radiator. This fluid is entirely diverted in one or more branches of the circuit external to the radiator, for example in a heat exchanger for heating the passenger compartment of the vehicle. This position is established when the engine is cold, and allows it to warm up quickly. It can also be seen in Figure 1 that the shutter 15 is spaced from the opening 5, thus allowing communication between the chambers 6 and 8, but this is of no consequence in the absence of fluid circulation in the radiator. The position illustrated in FIG. 3 corresponds to the end of the stroke of the rod 18 opposite to that corresponding to FIG. 1. The shutter 16 is spaced from the opening 14, allowing the fluid to enter the chamber 6. On the contrary, the shutter 15 closes the opening 5, preventing direct communication between the chambers 6 and 8. All of the fluid entering the radiator therefore passes from the chamber 6 to the fluid box 2 via the tubes. of the sub-assembly 10 (arrow F1), then of the fluid box 2 to the chamber 6 by the tubes of the sub-assembly 11 (arrow F2), before coming out through the tube 9. The radiator then operates in a conventional manner according to a "U" configuration. Its cooling efficiency is maximum. This position is established when the internal combustion engine is heavily loaded and releases a large calorific power.

In the intermediate part of the stroke of the rod 18, as illustrated in FIG. 2, the openings 5 and 14 are both released by the shutters 15 and 16 respectively. Part of the flow rate of the fluid entering the chamber, 6 through the opening 14 follows the same path as in FIG. 3, along the arrow f1 from the chamber 6 to the fluid box 2 through the tubes 10 and along the arrow f2 from the fluid box 2 to the chamber 8 via the tubes 11, while the rest of the flow passes directly from the chamber 6 to the chamber 8 through the opening 5, according to the arrow f3. This last part of the fluid is practically not cooled by its passage through the radiator, which limits the efficiency of the latter. The fraction of the flow passing through the tubes, and consequently the cooling efficiency, gradually increases when the rod 18 moves from the position of FIG. 1 to that of FIG. 3. It is thus possible to regulate the temperature of the heat engine by making vary the cooling efficiency according to its load. Taking into account the hydraulic pressure drop in the other branches of the cooling fluid circuit, the total flow rate of the fluid in the radiator can also vary gradually as a function of the position of the shutter 16, over at least part of its travel. , thus contributing to the regulatory action.

The radiator illustrated schematically in Figures 4 to 6 comprises elements identical or similar to those of Figures 1 to 3, which are designated by the same reference numbers increased by the number 100. The differences presented by the radiator of Figures 4 to 6 compared to that of FIGS. 1 to 3 are described below. The fluid box 102, opposite to the fluid box 101 through which the cooling fluid enters the radiator through the inlet pipe 107, is divided by a solid partition 121 into two chambers 122 and 123. The outlet pipe of fluid 109 opens into the chamber 123 of the fluid box 102, and not into the chamber 108 of the fluid box 101. The tubes of the bundle 103 are divided into three sub-assemblies 110, 111 and 124, the tubes of the sub-assembly 110 connecting the chambers 106 and 122, those of the sub-assembly 111 connecting the chambers 122 and 108 and those of the sub-assembly 124 connecting the chambers 108 and 123.

The positions of the shutters 116 and 115, which respectively control the entry of the fluid into the chamber 106 and the communication between the latter and the chamber 108, with respect to the corresponding openings 114 and 105 are the same in FIGS. 4 to 6 as the positions homologous shutters 16 and 15 in Figures 1 to 3 respectively. In the position of Figure 4, as in the case of Figure 1, the radiator is off. In the position of FIG. 6, it operates according to a "Z" circulation configuration: all of the fluid entering the chamber 106 through the inlet pipe 107 passes successively through the tubes of the sub-assembly 110 (arrow F101) , the chamber 122, the tubes of the sub-assembly 111 (arrow F102), the chamber 108, the tubes of the sub-assembly 124 (arrow F104) and the chamber 123 from which it emerges through the outlet pipe 109. In the position of FIG. 5, a fraction of the flow rate of the fluid which enters the chamber 106 follows the circuit which has just been described, the path in the tubes being indicated by the arrows f101, f102 and f104, while the rest of the fluid passes directly, through the opening 105, from the chamber 106 to the chamber 108 (arrow f103), where it joins the first fraction. The effects of this radiator are the same as those of the radiator of FIGS. 1 to 3, except that, in the intermediate position shown in FIG. 5, all of the fluid circulating in the radiator runs through the tubes of the sub-assembly 124 according to arrow f104. All other things being equal, the efficiency of the radiator in this position is therefore somewhat increased.

The radiator illustrated schematically in Figures 7 to 9 also comprises elements identical or similar to those of FIGS. 1 to 3, which are designated by the same reference numbers increased by the number 200. The differences with respect to the radiator of FIGS. 1 to 3 are described below. The fluid outlet pipe 209 of the radiator opens into the fluid box 202, opposite to the fluid box 201 through which the fluid enters the radiator through the inlet pipe 207. The tubes of the sub-assembly 210, which open into the chamber 206 of the fluid box 201, communicating with the pipe 207 through the opening 214, advantageously have a total passage section substantially smaller than that of the tubes of the subassembly 211 which open into the other chamber 208 of the same fluid box, while the passage sections of the tubes of the subassemblies 10 and 11 of the first embodiment are preferably substantially equal. While the shutter 216 is integral with the rod 218 of the actuator 217 and operates in the same way as the shutter 16 of the first embodiment, the shutter 215 associated with the opening 205 of the partition 204 which separates the chambers 206 and 208 is slidably mounted on the rod 218, by means of a sleeve 227 surrounding the latter, and is biased by a spring 226 which tends to apply it to the face of the partition 204 facing the chamber 208 so as to close the opening 205. The sliding movement of the shutter 215 on the rod 218 under the action of the spring 226 is limited by a shoulder or an enlargement 228 of the rod, on which the bush 227 abuts . In the positions of FIGS. 7 and 8, the stop 228 is moved away from the bush 227 and the spring 226 applies the shutter 215 to the opening 205 in order to close the latter. In the position of Figure 8, all of the coolant entering the chamber 206 through the opening 214 runs through the tubes of the subassembly 210 to reach the fluid box 202 from which it emerges through the outlet pipe 209 In the position illustrated in FIG. 9, the rod 218 pushes the sleeve 227 through the stop 228, compressing the spring 226, and the shutter 215 moves away from the opening 205. A fraction of the cooling fluid can thus penetrate through the latter into the chamber 208, so that the fluid traverses all of the tubes of the bundle 203 (arrows F205) to reach the fluid box 202. The radiator then operates in a circulation configuration "at I". In the intermediate position of FIG. 8, unlike the cases of FIGS. 2 and 5, all of the fluid entering the radiator circulates in the cooling tubes of the sub-assembly 210. However, the heat exchange surface is significantly reduced compared to the configuration in FIG. 9. In addition, the limitation of the number of tubes traversed leads to an increase in the hydraulic pressure drop through the radiator and consequently to a modification of the distribution of the flows in the circuit to the detriment of that -this. These two factors contribute to a deterioration in the efficiency of the radiator, which again allows temperature regulation of the heat engine.

The connection between the actuator 17, 117, 217 and the shutters 15, 115, 215 and 16, 116, 216, as described and illustrated here very schematically, can be achieved in practice by any means available to the tradesman. In addition, the relative geometric arrangement of these elements may be different from that which appears on the drawings. Furthermore, in the radiator of FIGS. 1 to 3, the tubes of the sub-assemblies 10 and 11 and the fluid box 2 can be replaced, in a manner known per se, by U-curved tubes, the two ends of each tube opening into rooms 6 and 8 respectively.

Claims (8)

1. - Radiator for cooling the heat engine of a motor vehicle, comprising a fluid box (1) provided with an inlet or outlet pipe (7) for a coolant, and a bundle of tubes (3 ) whose ends open into said fluid box, as well as a partition (4) provided with an opening 5, dividing the fluid box into a first chamber (6) into which open the inlet or outlet tubing ( 7) and a first sub-assembly (10) of the ends of the tubes, and in a second chamber (8) into which opens the complementary sub-assembly (11) of the ends of the tubes, and a first shutter (15) for the opening of the partition, movable under the effect of an actuator (17) between an open position for which the fluid entering the fluid box through the inlet pipe or leaving it through the outlet pipe can pass directly from the first room to the second or vice versa and a position closure for which this fluid necessarily passes through the tubes (10) to which the ends of the first subassembly belong, characterized in that it further comprises a second shutter (16) movable under the effect of said actuator (17) between an open position and a closed position of the communication between the inlet or outlet manifold and the first chamber, the actuator being able to pass from a first state in which the second shutter is in the closed position, preventing any circulation of the fluid in the radiator, in a second state in which the second shutter is in the open position and the first shutter is in a first of said open and closed positions, forcing the fluid which passes into the first chamber to circulate in all the radiator tubes, and vice versa, passing through an intermediate state in which the second shutter is in the open position and the first shutter is in the second of said positions, allowing the fluid to circulate only in a part of the tubes, or a part of the fluid only to circulate in the tubes. 2. - Radiator according to claim 1, characterized in that the two shutters are rigidly connected to each other, and are driven jointly by the actuator. 3. - Radiator according to claim 2, characterized in that the two shutters come in the closed position respectively for the two ends of the actuator stroke, and are both in the open position for the middle part of the stroke . 4. - Radiator according to claim 3, characterized in that it has a "U-shaped" circulation configuration, the inlet and outlet of the fluid being carried out by the two chambers of the fluid box (1) respectively, and the opening of the partition forming a fluid passage (f3) in diversion with respect to the set of tubes. 5. - Radiator according to claim 3, characterized in that it has a circulation configuration "Z" and comprises a fluid counter box (102) located opposite the fluid box (101) relative to the bundle of tubes (103) and divided by a partition (121) into a first chamber (123) into which opens a fluid outlet (or inlet) manifold (109) and into a second chamber (122), a first sub-assembly of the tubes (110) connecting the first chamber of the fluid box and the second chamber of the counter-fluid box, a second subset of the tubes (124) connecting the second chamber of the fluid box and the first chamber of the fluid counter box and the rest of the tubes (111) connecting the second chambers of the fluid box and of the fluid counterbox, the opening of the partition of the fluid box forming a fluid passage (f103) in diversion relative to the first subset and the rest of the tubes. 6. - Radiator according to claim 1, characterized in that the first shutter (215) is linked to the second shutter (216) so as to remain immobilized over part of the stroke thereof, adjacent to its closed position, and to be united for the rest of its course. 7. - Radiator according to claim 6, characterized in that the first shutter is in the closed position on said part of the travel of the second shutter. 8. - Radiator according to claim 7, characterized in that it has a circulation configuration "I" and comprises a fluid counter box (202) without partition into which opens an outlet pipe (or inlet) of fluid (209) and connected to the fluid box (201) for all the tubes, the closing of the partition (204) of the fluid box preventing the fluid from passing into the second chamber thereof and into the tubes (211) which open there.

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