JP2020509282A - Regenerative cooling system - Google Patents

Abstract

A regenerative cooling system (100) is provided for the regenerative heat engine (1) and is a cooling chamber (79) surrounding the gas expander (78), wherein the cooling chamber (79) is connected to the expander (78). A cooling chamber (79) that keeps the gas circulation space (80) open between them, and a regenerative heat exchange after the working gas (81) is exhausted from the gas expander (78) and circulated through the space (80). Returning to the unit (5), where it is cooled, most of the heat of the gas (81) is reintroduced into the thermodynamic cycle of the regenerative heat engine (1). [Selection diagram] Fig. 1

Description

  The present invention is, inter alia, an improvement of the transfer-expansion and regeneration heat engine that was the subject of patent application FR 15 51593, filed Feb. 25, 2015, belonging to the applicant. With regard to the regenerative cooling system to be constituted, the patent was published on September 1, 2016 as U.S. Patent Application Publication No. 2016/0252048 A1, also belonging to the applicant.

  Brayton regeneration cycles commonly performed using centrifugal compressors and turbines are well known.

  According to this embodiment, this cycle results in an engine that offers significantly higher efficiency than a controlled ignition engine. Its efficiency is comparable to that of high speed diesel engines. However, it remains lower than that of low speed two-stroke diesel engines with very large displacements found, for example, in naval propulsion or stationary power generation.

  In addition to the very modest overall efficiency, engines with centrifugal compressors and turbines that use the Brayton regeneration cycle offer their highest efficiency over a relatively narrow range of power and rotational speeds. Furthermore, their response time in output modulation is long. For these various reasons, their scope of application is limited and they are difficult to adapt to land transportation, especially passenger cars and trucks.

  To remedy these drawbacks, a heat transfer-expansion and regenerative heat engine of patent application FR 15 51 593 was proposed. The engine has the special feature that it implements a regenerative Brayton cycle no longer by centrifugal compressors and turbines, but rather by positive displacement machines or at least by positive displacement expanders formed around "expander cylinders".

  In the drawing of patent application FR 15 51 593, each end of the expander cylinder is closed by an expander cylinder head, the cylinder acting dually to form two heat transfer-expansion chambers of variable capacity. Notice that it houses the expander piston. The piston can be displaced in the expander cylinder to transfer work to the power output shaft via the well-known connecting rod and crankshaft.

  Among the advantages claimed by the present invention, which are the subject of patent application FR 15 51 593, include a much higher efficiency of converting heat to work than that of an alternative conventional internal combustion engine of any operating principle. Yes, for the same task, the measures provided lower fuel consumption than the conventional engines and also lower associated carbon dioxide emissions.

  As clearly stated in patent application FR 15 51 593, at least three conditions need to be fulfilled in order to achieve these objectives.

  The first condition is that the volume expander is efficiently constructed from a single cylinder, which is not the teaching of the prior art dealing with such machines. By way of example, U.S. Patent Application Publication No. 2003/228237 A1 on December 11, 2003 actually includes a compressor, a regenerative heat exchanger, a heat source and an expander, but the expander is not a cylinder, but instead a cylinder. What the inventors of the patent refer to as "Gerotor".

  The second condition is that the inlet and outlet of the gas in the expander cylinder is regulated by a properly adjusted intake and exhaust metering valve, so that the pressure vs. volume shown in the diagram of patent application FR 15 51 593 is shown. Is obtained.

  A third condition is that the sealing device between the piston and the cylinder can operate at very high temperatures.

  The heat transfer-expansion and regeneration heat engine described in patent application FR 15 51593 is formed by a continuous perforated inflatable and expandable ring housed in an annular groove devised in an expander piston. Note that this third condition is met by proposing an innovative air cushion segment. The ring, together with the groove, defines a pressure distribution chamber connected to a source of pressurized fluid.

  This new sealing device, which does not come into direct contact with the expander cylinder, allows operation of the cylinder at high temperatures, while the intake and exhaust metering valves in the cylinder head that close the cylinder are equipped with heat transfer-expansion and regenerative heat engines. Enables to maximize efficiency.

  An innovative sealing device based on an air cushion segment was intentionally placed in patent application FR 15 51 593 in the dependent claims of the main claim. As will be readily appreciated, by presenting his invention in this manner, the inventor may also be presented in the above-mentioned patent application with the segment being a key element of a heat transfer-expansion and regenerative heat engine. Did not rule out other sealing solutions that could replace the above segments.

  As specified in patent application FR 15 51 593, in order to make the efficiency of the heat transfer-expansion and regenerative heat engine as high as possible, the inner walls of the expander cylinder are brought to a high temperature and are thereby introduced into said cylinder. It is necessary to ensure that the heated hot gases are not cooled when they come into contact with their walls, or at least are cooled by the walls as little as possible. This applies at least to the inner wall of the expander cylinder itself and to the inner wall of the cylinder head cooperating with said cylinder.

  According to the principle of engine thermodynamics presented by Sadi Carnot, patent application FR 15 51 593 discloses that the efficiency of a heat transfer-expansion and regeneration heat engine is such that the higher the temperature of the gas introduced into the expander cylinder, the greater the temperature Propose that.

  This is because patent application FR 15 51 593 discloses that heat transfer-expansion and regeneration heat engine expander cylinders, cylinder heads and expander pistons of expander cylinders are made of ceramics based on alumina, zircon or silicon carbide. That is why it is required to be made from materials that withstand very high temperatures.

  Furthermore, the hot sections and hot components of heat transfer-expansion and regenerative heat engines are the subject of patents relating to improvements on such engines. Thus, reference may be made to patent application FR 15 58585, filed Sep. 14, 2015, belonging to the applicant, which deals with dual-action and adaptive-supporting expander cylinders, said cylinders being able to operate at high temperatures. And can be subjected to a different thermal expansion than the transmission case to which it is attached. Similarly, a patent application FR 15 58593, filed Sep. 14, 2015, also belonging to the applicant, consists of a prestressed assembly and is capable of operating at temperature You will notice that it deals with.

  Note that the above cited patent applications FR 15 58585 and FR 15 58593 propose a very robust solution for addressing the presence of hot and cold components in the same device. I want to be.

  In particular, the arrangement proposed in the above patent significantly prevents heat from transferring from the hot components to the cold components with which they cooperate. This ensures that the efficiency of the heat transfer-expansion and regeneration heat engine is improved.

  On the other hand, the improvements proposed in patent applications FR 15 58585 and FR 15 58593 are that if the temperature of the gas introduced into the expander cylinder of the engine is, for example, 1300 ° C., the temperature of the inner wall of that cylinder Does not change the fact that the local temperature approaches 1300 ° C. and the average temperature of those walls approaches 1000 ° C., for example.

  Thus, the temperature of these gases directly determines the temperature that the material that makes up the hot section of the expander cylinder of the heat transfer-expansion and regenerative heat engine must withstand. Therefore, indirectly, the temperature resistance of these materials determines the maximum source availability of the engine.

  In addition, the materials in question, which can withstand very high temperatures, are relatively resistant to corrosion and oxidation, while still providing a high mechanical strength at these same temperatures, so that relatively few Note that there is.

  The material is mainly a ceramic such as alumina, zircon, silicon carbide or silicon nitride. These materials are hard and difficult to machine. As a result, the selling price of the finished part is relatively high, which is an obstacle to the adoption by the automotive industry of heat transfer-expansion and regenerative heat engines as described in patent application FR 15 51 593. In fact, since this industry targets the consumer market, it is very sensitive to manufacturing and selling prices, which need to be as low as possible.

  Therefore, ideally, the inner wall of the expander cylinder of this engine would be maintained at a maximum temperature of, for example, 700-900C. In fact, at such temperatures, expander cylinders can be manufactured using more common materials that are less expensive to manufacture and machine than ceramics, such as cast iron or stainless steel or refractories. The same applies to the cylinder head and the respective plenums and ducts cooperating with the cylinder.

  However, on the one hand, it prevents the temperature of the hot gases introduced into the expander cylinders of the heat transfer-expansion and regenerative heat engines, and, on the other hand, transfers the heat of these gases to the cooler walls of the cylinders they contact. It is imperative to allow them to escape as pure losses through. In fact, these two effects will have the deleterious consequences of significantly reducing the final efficiency of the heat transfer-expansion and regenerative heat engines.

  Thus, the current state of the art relies on heat transfer-expansion and regenerative heat engines, which are very efficient but costly and difficult to manufacture, and materials based on the same principles but less expensive to manufacture, but Need to choose between institutions that sacrifice a significant decline in This is a dilemma.

To solve this dilemma, the regenerative cooling system of the present invention in one particular embodiment allows:
Without significantly reducing the temperature of the inner wall of the expander cylinder and its cylinder head of the heat transfer-expansion and regenerative heat engine, which is the subject of patent application FR 15 51 593, without significantly reducing the overall efficiency of said heat engine; To enable the use of lower selling price materials to manufacture the cylinders and their cylinder heads.
-In the absence of a regenerative cooling system according to the invention, allowing the suction of gas into the expander cylinder at a higher temperature than is possible for expensive and complex materials such as ceramics.
Heat transfer which is the subject of patent application FR 15 51 593 having higher final energy efficiency with lower selling price materials than is possible for the same engine with expensive and complex materials such as ceramics Providing an expansion and regeneration heat engine;

  It is understood that the regenerative cooling system according to the invention is mainly directed to the heat transfer-expansion and regenerative heat engine which is the subject of patent application FR 15 51 593 belonging to the applicant.

  However, the system is also independent of whether the expander is a centrifuge, a positive displacement, or any other type, and it works with any given type of regenerator And may be applied without limitation to any other institutional expander that has a Brayton regeneration cycle.

  Other features of the invention are set forth in the description and in the sub-claims which are directly or indirectly dependent on the main claim.

The regenerative cooling system according to the invention is designed for a regenerative heat engine, which comprises at least one regenerative heat exchanger having a high-pressure regenerative duct, in which a working gas pre-compressed by a compressor is passed. At the outlet of the duct, while the gas is superheated by a heat source and then introduced into a gas expander, where it is expanded to perform work on a power output shaft, where the gas is expanded. Is then discharged at the outlet of the gas expander and introduced into the low-pressure regeneration duct of the regenerative heat exchanger, and the gas circulates in the duct, circulating most of its residual heat in the high-pressure regeneration duct. To the working gas,
At least one cooling chamber which entirely or partially surrounds a gas expander and / or a heat source and / or a hot gas intake duct connecting said heat source to said expander, on the one hand said chamber and / or on the other hand At least one cooling chamber, which leaves the gas circulation space between the expander and / or the heat source and / or the duct open;
At least one chamber inlet connected directly or indirectly to the outlet of the gas expander so that some or all of the working gas discharged from the expander via the outlet can enter the gas circulation space; port,
It comprises at least one chamber outlet port connected directly or indirectly to the low-pressure regeneration duct, whereby the working gas can exit the gas circulation space before being introduced into said low-pressure duct;

  The regenerative cooling system according to the invention comprises a chamber inlet port connected to the outlet of the gas expander by a chamber inlet duct whose effective cross section is regulated by a flow control valve.

  The regenerative cooling system according to the invention comprises a chamber outlet port connected to the low pressure regeneration duct by a chamber outlet duct whose effective cross section is regulated by a flow control valve.

  A regenerative cooling system according to the present invention comprises an outlet of a gas expander connected to a low pressure regeneration duct by a chamber bypass duct.

  A regenerative cooling system according to the present invention includes an effective cross-section of a chamber bypass duct regulated by a flow control valve.

  A regenerative cooling system according to the present invention includes an exterior of a cooling chamber coated with a thermal barrier.

  The following description, taken in conjunction with the accompanying drawings and given as non-limiting examples, will allow a better understanding of the invention, its features, and the advantages it may provide.

FIG. 1 is a schematic side view of a regenerative cooling system according to the present invention as may be implemented in a heat transfer-expansion and regenerative heat engine, which is the subject of patent application FR 15 51 593 belonging to the Applicant; According to a variant, the outlet of the gas expander is connected by a chamber bypass duct to the low-pressure regeneration duct, so that the effective cross sections of the bypass duct and the chamber outlet duct are adjusted by the flow control valve.

  FIG. 1 shows various details of the regenerative cooling system 100, its components, its variants, and its accessories.

  As shown in FIG. 1, the regenerative cooling system 100 is provided for a regenerative heat engine 1, which has at least one regenerative heat exchanger 5 having a high-pressure regenerative duct 6, and inside the high-pressure regenerative duct 6. The working gas 81 previously compressed by the compressor 2 circulates and is heated there.

  Upon exiting the high pressure regeneration duct 6, the gas 81 is superheated by the heat source 12 before being introduced into the gas expander 78 where it is expanded to provide work to the power output shaft 17.

  The working gas 81 is then discharged from the gas expander 78 and introduced into the low-pressure regeneration duct 7 of the regenerative heat exchanger 5, and the gas 81 circulates in the high-pressure regeneration duct 6 by circulating in the duct 7. To a considerable extent its working heat 81.

  In this connection, the following is clearly shown in FIG. The regenerative cooling system 100 according to the present invention comprises at least one cooling chamber 79, which comprises a gas expander 78 and / or a heat source 12 and / or a hot gas intake duct 19 connecting said heat source 12 to the expander 78. While the chamber 79 and / or the expander 78 and / or the gas circulation space 80 between the heat source 12 and / or the duct 19 are left open, Gas 81 can circulate in this space 80.

  The cooling chamber 79 can be made from a drawn or hydroformed stainless steel sheet, which may be realized with several parts assembled together by welding, screwing or riveting, Note that the chamber may be attached directly or indirectly to the components 78, 12, 19 it surrounds.

  FIG. 1 shows a regenerative cooling system 100 according to the present invention having at least one chamber inlet port 82 connected directly or indirectly to a gas expander 78, thereby discharging from the expander 78 via the outlet. It is shown that a part or all of the working gas 81 further includes a chamber inlet port 82 through which the gas circulation space 80 can enter.

  Referring again to FIG. 1, the regenerative cooling system 100 according to the present invention also includes at least one chamber outlet port 83 connected directly or indirectly to the low pressure regeneration duct 7, whereby the working gas 81 is supplied to the low pressure duct 7. Will be provided with a chamber exit port 83 that can leave the gas circulation space 80 before being introduced into the chamber.

  Preferably, the cooling chamber 79 tightly surrounds the gas expander 78 and / or the heat source 12 and / or the hot gas entry duct 19 so that the working gas 81 enters the gas circulation space 80 only through the chamber inlet port 82. Note, on the other hand, that the gas 81 can leave the space 80 only through the chamber outlet port 83.

  According to one variant embodiment of the regenerative cooling system 100 according to the invention as shown in FIG. 1, the chamber inlet port 82 can be connected via a chamber inlet duct 84 to the output of a gas expander 78, The effective cross section of the duct 84 is adjusted by a flow control valve 85 which, depending on its position, can prevent, allow or limit the circulation of the working gas 81 in said duct 84.

  As shown in FIG. 1 again, as another variant, the chamber outlet port 83 can be connected to the low-pressure regeneration duct 7 by a chamber outlet duct 86, the effective cross section of the chamber outlet duct 86 being adjusted by a flow control valve 85. The flow control valve 85 can prevent, allow, or limit the circulation of the working gas 81 in the chamber outlet duct 86 depending on its position.

  FIG. 1 also shows another variant of the regenerative cooling system 100 according to the invention, in which the working gas 81 is discharged from the outlet of the gas expander 78 and directly from this outlet without moving through the gas circulation space 80. 7 shows that the outlet of the gas expander 78 can be connected to the low-pressure regeneration duct 7 by a chamber bypass duct 87 that allows the process to proceed to 7.

  According to this latter variant, the effective cross-section of the chamber bypass duct 87 can optionally be adjusted by the flow control valve 85, which, depending on its position, is provided in the bypass duct 87 The circulation of the working gas 81 may be blocked, allowed or restricted.

  In FIG. 1, the outside of the cooling chamber 79 can be advantageously covered with a thermal barrier 88, which can be formed from any insulating material known to those skilled in the art, It should be noted that in addition to the cooling chamber 79, various high-temperature ducts and elements constituting the regenerative heat engine 1 can be coated.

  In this case, it should be noted that the heat shield 88 is provided to prevent excessive heat loss that is not desirable for the efficiency of the regenerative heat engine 1.

Features of the Present Invention The features of the regenerative cooling system 100 according to the present invention will be readily understood by considering FIG.

  To describe this function, an exemplary embodiment of the regenerative cooling system 100 according to the invention will be used here, where the regenerating engine 1 to which it applies is February 25, 2015 belonging to the applicant. Consisting of a transfer-expansion and regenerative heat engine which is the subject of Japanese Patent Application FR 15 51593.

  As can be seen from FIG. 1, the regeneration engine 1 here includes a two-stage compressor 2 including a low-pressure compressor 35 that takes in a working gas 81 from the atmosphere via a compressor inlet duct 3. Is connected to the inlet of the high-pressure compressor 36 via the intermediate compressor cooler 37.

  FIG. 1 shows that at the outlet of the high-pressure compressor 36, the working gas 81 is discharged into the high-pressure regeneration duct 6, which comprises a regenerative heat exchanger 5, in this case a countercurrent heat exchanger 41, which is well known per se. Is shown. It is assumed here that the working gas 81 is discharged from the high-pressure compressor 36 at a pressure of 20 bar and a temperature of 200 ° C.

  By circulating in the high-pressure regeneration duct 6, the working gas 81 is preheated to a temperature of 650 ° C. by the high-temperature working gas 81 circulating in the adjacent low-pressure regeneration duct 7.

  For simplicity, consider that the efficiency of the regenerative heat exchanger 5 is 100%. This is because the working gas 81 circulating in the low-pressure regeneration duct 7 enters the low-pressure regeneration duct 7 at a temperature of 650 ° C., exits the duct 7 at a temperature of 200 ° C., and then enters the atmosphere via the engine outlet duct 33. Meanwhile, it means that the working gas 81 circulating in the high-pressure regeneration duct 6 enters the high-pressure regeneration duct 6 at a temperature of 200 ° C. and exits at a temperature of 650 ° C.

  Upon leaving the high-pressure regeneration duct 6, the working gas 81 is superheated to 1400 ° C. by the heat source 12, which according to the exemplary embodiment comprises a fuel burner 38.

  Upon leaving the burner 38, the working gas 81 is carried by the hot gas intake duct 19 to the gas expander 78. The gas expander 78 is in fact the expander cylinder 13 of a transfer-expansion and regenerative heat engine which is the subject of patent application FR 15 51 593.

  It is noted that the hot gas intake duct 19 is preferably made of a high temperature resistant ceramic up to its connection to the expander cylinder head 14 covering one end or the other end of the expander cylinder 13. I want to. Therefore, the temperature of this duct 19 is maintained substantially equal to 1,400 ° C. so that the working gas 81 circulating in said duct 19 keeps its temperature along its entire path.

  Thus, as shown in FIG. 1, each end of the expander cylinder 13 is covered by an expander cylinder head 14 so as to define two transmission-expansion chambers 16 with a dual acting expander piston 15. . Also note that each cylinder head has an intake metering valve 24 and an exhaust metering valve 31.

  Thanks to the regenerative cooling system 100 according to the invention, the transfer-expansion and regenerative heat engine is hot, but the expander cylinder 13 and the cylinder head 14 of the expander cylinder are kept close to 700 ° C. This makes it possible to form the cylinder 13 and the cylinder head 14 from common materials at a lower cost than ceramics such as stainless steel or ferrite silicon cast iron.

  With respect to the dual-action expander piston 15 and according to this non-limiting example of the regenerative cooling system 100 of the present invention, it is manufactured from silicon nitride. The average operating temperature of the piston 15 is about 800 ° C.

  In FIG. 1 it will be noted that the piston 15 is connected to the power output shaft 17 by a mechanical transmission means 19, said means 19 comprising in particular a connecting rod 42 connected to a crank 43.

  The working gas 81 rises to a pressure of 20 bar, so that a temperature of 1,400 ° C. is introduced into one or the other heat transfer-expansion chamber 16 by the corresponding intake metering valve 24.

  Upon passing through the orifice held open by the intake metering valve 24, the gas 81 begins to cool slightly, especially when it comes into contact with the inner wall of the expander cylinder head 14 through which it passes, and Upon contact with the inner wall of the heat transfer-expansion chamber 16 which is introduced to be expanded there by the heavy expander piston 15, it begins to cool slightly. The wall is maintained at 700 ° C. by the regenerative cooling system 100, as seen above.

  At this point, it is assumed that the working gas 81 loses an average of 100 ° C. by sweeping the inner wall of the expander cylinder head 14 and the inner wall of the heat transfer-expansion chamber 16. As a result, the temperature of the working gas 81 decreases while moving from the hot gas intake duct 19 to the heat transfer-expansion chamber 16 and moves from 1,400 ° C. to 1,300 ° C.

  When the desired amount of working gas 81 has been effectively introduced into the heat transfer-expansion chamber 16 by the corresponding intake metering valve 24, the intake metering valve 24 is closed and the dual action expander piston 15 is brought into contact with the gas 81. Inflate. In doing so, the piston 15 harvests the work generated by the gas 81 and transmits this work to the power output shaft 17, particularly via the connecting rod 42 and the crank 43.

  When the working gas 81 is expanded by the double acting expander piston 15, the pressure of the gas 81 drops by about 1 absolute bar. The same applies to the temperature of this gas 81, which varies from 1,300 ° C. to 550 ° C.

  When the dual action expander piston 15 reaches the bottom dead center, the exhaust metering valve 31 opens, the piston 15 discharges the gas 81 to the chamber inlet duct 84, and the chamber inlet duct 84 transfers the gas 81 to the chamber inlet duct. Carry to port 82.

  Then, the working gas 81 enters the gas circulation space 80 and is directed to the chamber outlet port 83 via this space. By doing so, the gas 81 cleans the hot outer walls of the expander cylinder 13 and the cylinder head 14 of the expander cylinder. The outer wall may be roughened in whole or in part to cause forced convection that causes the working gas 81 to draw more or less heat from the wall as the gas 81 circulates in contact with these walls. And / or are interspersed with geometric patterns.

  Furthermore, the internal shape of the cooling chamber 79 and / or the external shape of the expander cylinder 13 and / or the external shape of the cylinder head 14 of the expander cylinder are advantageously such that all or a part of the working gas 81 is supplied to the chamber inlet port. A channel may be formed which forces one or several simultaneous paths from 82 through the gas circulation space 80 to the chamber outlet port 83.

  The dual strategy of forced convection and forced path of the working gas 81 is firstly to select a zone that discharges heat from the hot outer wall of the expander cylinder 13 and the cylinder head 14 of the expander cylinder to the gas 81. Secondly, selecting the order of the zones to be swept away by the gas 81, and thirdly and finally, allowing to select the intensity of forced convection along the path of the gas 81. Will be understood.

  In any case, while moving through the cooling chamber 79, the temperature of the working gas 81 rises from the high-temperature outer walls of the expander cylinder 13 and the cylinder head 14 of the expander cylinder so that the temperature of the gas 81 becomes 550 ° C. to 650 ° C. Pull heat to a point that gradually changes to. In doing so, and in conjunction with the forced convection and path strategy selected for the working gas 81, the gas homogenizes the temperature of the expander cylinder 13 and the temperature of the expander cylinder cylinder head 14, The temperature is kept close to 700 ° C.

  When working gas 81 reaches its new temperature of 650 ° C., gas 81 reaches chamber outlet port 83 and returns to low pressure regeneration duct 7 via chamber outlet duct 86.

  As will be appreciated from the preceding description, the working gas 81 discharged from the chamber outlet port 83 by circulating through the low pressure regeneration duct 7 and before being discharged to the atmosphere via the engine outlet duct 33 is Most of the heat is given to the working gas 81 circulating in the adjacent high-pressure regeneration duct 6.

  Finally and thanks to the regenerative cooling system 100 according to the invention, the heat extracted from them to maintain the expander cylinder 13 and the cylinder head 14 of the expander cylinder at a temperature of about 700 ° C. is dissipated as pure losses. Not done.

  In fact, that heat is provided by the fuel burner 38 to bring the working gas 81 to a temperature of 1400 ° C. before being sent to the expander cylinder 13 and then introduced into the heat transfer-expansion chamber 16. It is reintroduced into the thermodynamic cycle of the regenerative heat engine 1 to replace some of the required heat.

  In FIG. 1, you will notice a chamber bypass duct 87 with a flow control valve 85. Also in FIG. 1, you will notice that the chamber outlet duct 86 has a flow control valve 85 as well. These two valves 85 constitute a modified embodiment of the regenerative cooling system 100 according to the invention and are provided for adjusting the temperature of the expander cylinder 13 and the cylinder head 14 of the expander cylinder.

  In fact, if the temperature is too high, the flow control valve 85 of the chamber bypass duct 87 will close the bypass duct 87, while the flow control valve 85 of the chamber outlet duct 86 will open its outlet duct 86. This has the effect that the working gas 81 discharged from the heat transfer / expansion chamber 16 by the respective exhaust gas metering valves 31 is forcibly passed through the circulation space 80 and returned to the low-pressure regeneration duct 7.

  On the other hand, if the temperatures of the expander cylinder 13 and the cylinder head 14 of the expander cylinder are too low, the flow control valve 85 of the chamber bypass duct 87 opens the bypass duct 87, while the flow control valve 85 of the chamber outlet duct 86 opens. Is closed. This has the effect of preventing the working gas 81 discharged from the heat transfer-expansion chamber 16 by the respective exhaust gas metering valves 31 from returning to the low-pressure regeneration duct 7 through the gas circulation space 80. Therefore, the gas 81 returns directly to the duct 7 via the chamber bypass duct 87.

  In practical use, the flow control valve 85 is rarely either fully open or fully closed, and the valve 85 does not suddenly change the flow rate of the working gas 81 circulating in the gas circulation space 80. It will be appreciated that the temperature of the expander cylinder 13 and the cylinder head 14 of the expander cylinder can be maintained slightly open to adjust.

  The temperature adjustment requires, for example, a control device composed of at least one temperature sensor and one microcontroller, which are known per se and each have a flow control valve 85. It will also be appreciated that it is possible to control any kind of servomotor to operate to open and close.

  According to a particular embodiment of the regenerative cooling system 100 according to the invention, the flow control valves 85 can also be connected together by a mechanical connection to share the same servomotor. In this case, the connection ensures that the second valve 85 is opened when the first valve 85 is closed and vice versa.

  The regenerative cooling system 100 according to the present invention has many advantages, particularly when implementing the heat transfer-expansion and regenerative heat engines that are the subject of the applicant's patent application FR 15 51593. It will be easy to conclude from the description.

  First, there is no need to manufacture the expander cylinder 13 and the cylinder head 14 of the expander cylinder from a ceramic material such as silicon carbide. In fact, materials of this kind are known to be expensive to manufacture, because their high hardness makes them difficult to machine using conventional cutting or polishing tools. Thanks to the regenerative cooling system 100 according to the invention, it is possible to replace such ceramics with cast iron or stainless steel. This greatly reduces the manufacturing and selling price of heat transfer-expansion and regenerative heat engines, which is especially critical for such engines entering the automotive market.

  As a second advantage, since the expander cylinder 13 and the cylinder head 14 of the expander cylinder are colder, the adaptive support, which is the subject of patent application FR 15 58585, filed Sep. 14, 2015, belonging to the present applicant, is provided. Materials with very low thermal conductivity and high compressive strength, such as quartz, can be used to manufacture the hollow pillars of a dual action expander cylinder with In fact, quartz does not adapt to a temperature of 1300 ° C., but it adapts perfectly to a temperature of 700 ° C. It should be noted here that the dual-action expander cylinder with the adaptive support in question is one of the important improvements in heat transfer-expansion and regenerative heat engines.

  Third, because the cylinder head 14 of the expander cylinder is maintained at 700 ° C., they may use existing silicon nitride valves to accommodate these temperature levels. Such a valve has been developed, for example, by the company "NGK" and has been specifically funded under the framework of the 5th European FP5-GROWTH program entitled "LIVALVES" and entitled Project No. In the context of G3RD-CT-2000-0248, it was the subject of investigation for their low cost industrialization.

  A fourth advantage is that, since the temperature of the inner wall of the expander cylinder 13 is maintained at around 700 ° C., the air cushion segments as proposed in the patent application FR-1551593 belonging to the present applicant can be used at these temperatures. Can be manufactured from a superalloy that is durable to a certain level, especially when the heat transfer-expansion and regenerative heat engine is shut down and before it cools down, the segment is brought to a temperature significantly higher than 700 ° C. There is no risk of exposure.

  As a fifth advantage, when applied to the heat transfer-expansion and regenerative heat engine which is the subject of patent application FR 15 51 593, the regenerative cooling system 100 according to the invention comprises an expander cylinder 13 and a cylinder of the expander cylinder. This makes it possible to limit the thermal exposure of the thermal barrier 88 surrounding the head 14. In fact, the cooling chamber 79 is inserted between these shields 88 on the one hand and the cylinder 13 and the cylinder head on the other hand. Therefore, the selling price and durability of the shield 88 are greatly improved.

  These advantages are obtained without interfering with the final energy efficiency of the heat transfer-expansion and regenerative heat engine.

  In contrast, the regenerative cooling system 100 according to the present invention, on the one hand, has the temperature resistance of the material forming the expander cylinder 13 and the cylinder head 14 of the expander cylinder and, on the other hand, the temperature of the working gas 81 leaving the fuel burner 38 and the temperature. Between the existing applications according to patent application FR 15 51593.

  To some extent, thanks to the regenerative cooling system 100 according to the present invention, the fuel burner has to be improved in order to improve the heat transfer-expansion and the final efficiency of the regenerative heat engine and without compromising the temperature stability of the main elements constituting the engine. It is conceivable to raise the temperature of the working gas 81 coming out of 38.

  In addition to the heat transfer-expansion and regenerative heat engine that is the subject of patent application FR 15 51 593, the regenerative cooling system 100 according to the present invention has any other regenerative heat whose configuration and temperature characteristics are compatible with the system 100 described above. Note that it can be advantageously applied to the engine 1.

  Therefore, the potential of the regenerative cooling system 100 according to the present invention is not limited to the application just described, the foregoing description is given by way of example only, It should be further understood that they do not in any way limit the scope of the above-described invention, which is not circumvented by substituting with the equivalents of

Claims (6)

A regenerative cooling system (100) designed for a regenerative heat engine (1), said regenerative heat engine (1) comprising at least one regenerative heat exchanger (5) having a high-pressure regenerative duct (6). The working gas (81) precompressed by the compressor (2) circulates in the high-pressure regeneration duct (6) so as to be preheated there, while the gas at the outlet of the duct (6) (81) is superheated by a heat source (12) and then introduced into a gas expander (78) where it is expanded to perform work on a power output shaft (17), and the gas (81) is then The gas is discharged at the outlet of the gas expander (78) and introduced into the low-pressure regeneration duct (7) of the regenerative heat exchanger (5). The gas (81) circulates in the duct (7), Most of that residual heat The delivery to the working gas (81) for circulating the high pressure regeneration duct (6) within said system (100),
At least totally or partially surrounding the gas expander (78) and / or the heat source (12) and / or the hot gas intake duct (19) connecting the heat source (12) to the expander (78); Gas circulation between one cooling chamber (79), on the one hand said chamber (79) and / or on the other hand said expander (78) and / or said heat source (12) and / or said duct (19) At least one cooling chamber (79) leaving the space (80) open;
A direct or indirect connection to the outlet of the gas expander (78), whereby some or all of the working gas (81) discharged from the expander (78) via the outlet is the gas At least one chamber inlet port (82) capable of entering the circulation space (80);
Connected directly or indirectly to the low pressure regeneration duct (7) so that the working gas (81) can exit the gas circulation space (80) before being introduced into the low pressure duct (7). A regenerative cooling system (100), comprising at least one chamber outlet port (83).   The chamber inlet port (82) is connected to the outlet of the gas expander (78) by a chamber inlet duct (84) whose effective cross section is regulated by a flow control valve (85). 2. The regenerative cooling system according to 1.   The chamber outlet port (83) is connected to the low-pressure regeneration duct (7) by a chamber outlet duct (86) whose effective cross section is regulated by a flow control valve (85). A regenerative cooling system as described.   The regenerative cooling system according to claim 1, characterized in that the outlet of the gas expander (78) is connected to the low-pressure regeneration duct (7) by a chamber bypass duct (87).   The regenerative cooling system according to claim 4, characterized in that the effective cross section of the chamber bypass duct (87) is adjusted by a flow control valve (85).   The regenerative cooling system according to claim 1, characterized in that the outside of the cooling chamber (79) is coated with a thermal barrier (88).

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