MXPA96003023A - Method and apparatus for the thermal administration of vehicu exhaust systems - Google Patents

Abstract

The present invention relates to a combustion heat management apparatus, comprising: a catalytic converter and a substrate that provide structure and support surface for the catalyst to catalyze the oxidation or reduction reactions with contaminants in the combustion gases; catalyst housing element for containing the catalytic converter element and for channeling the combustion gases towards the catalytic converter element, and insulating means with variable conductance surrounding the catalyst housing element to selectively isolate the housing element to inhibit the transfer of the catalyst. heat radially from the housing element in response to a first signal or to enable heat transfer in response to a second signal

Description

METHOD AND APPARATUS FOR THE THERMAL ADMINISTRATION OF VEHICLE EXHAUST SYSTEMS Cross reference with related applications This patent application is a continuation in part of the Serial US patent application No. 07 / 960,885 filed on October 14, 1992, which is a continuation in part of the serial US patent application No. 07 / 856,840 filed on March 23, 1992, (now U.S. Patent No. 5,175,975), which is a continuation in part of U.S. Patent Application No. 07 / 181,926, filed April 15, 1988, now abandoned , and the North American patent application No. 07 / 960,885 is also a continuation in part of U.S. Patent Application No. 07 / 535,872, filed July 12, 1990 (now U.S. Patent No. 5,157,893) which is a continuation in part of the North American series No. 07 / 181,926 filed April 15, 1988. Technical Field This invention relates generally to automobile exhaust systems and particularly to systems for managing and utilizing the heat generated in catalytic converters. BACKGROUND OF THE INVENTION Most vehicle exhaust systems and particularly exhaust systems of vehicles powered by internal combustion engines powered by gasoline are equipped with catalytic converters to reduce harmful emissions in combustion gases. The most effective current technology catalytic converters comprise ceramic substrates coated with one or more noble metal catalysts, such as platinum, palladium, or rhodium. The preferred noble metal for the reduction of high temperature hydrocarbon is palladium, and rhodium is effective in improving emissions of nitrous oxide and carbon monoxide. The so-called three-way catalytic converters typically include combinations of these noble metals that catalyze two oxidation reactions which oxidize carbon monoxide to carbon dioxide and oxidize hydrocarbons to carbon dioxide and water. At the same time, nitrogen oxides are reduced to nitrogen and oxygen. These reactions are very effective at certain high temperatures. However, until the catalyst is heated to its fresh-off temperature, defined as the temperature required to oxidize 50% of the hydrocarbons, the effectiveness of the catalytic converters is very low. For example, J.C. Summers and collaborators, in their paper "Use of Evaporation Catalysts to Meet California LEV / ULEV Standards", Catalyst and Emissions Technology, Special Publication of the Society of Automotive Engineers No. 968, Arrendale, PA, 1993, reported that Approximately 60-70% of the hydrocarbon emissions from the exhaust pipe occur during the initial phase of cold start (Bag 1). To reach the fresh off temperature more quickly, it is desirable to retain the heat of combustion as much as possible in the catalytic converter, at least until the fresh off temperature is reached, usually in the range of 31.55 ° -426.7 ° C ( 600 ° -800 ° F). Providing an insulating jacket around the catalytic converter can help retain heat. However, the temperature of a catalytic converter during the prolonged operation once the temperature of freshly turned off is reached can rise very rapidly from the exothermic heat of the catalytic reactions with the combustion gases. If the heat generated during prolonged operation or the fuel-rich gases reacted in the catalytic converter can not be dissipated efficiently, they can accumulate to a point that can result in accelerated aging of the catalyst or even in permanent damage to the catalytic converter or adjacent components or objects. Therefore, the maximum desired operating range is usually about 1, 500 ° F. This problem was addressed by U.S. Patent No. 5,163,289, issued to D. Bainbridge, which discloses an insulating jacket around a catalytic converter where the insulator is a refractory fiber that conducts heat better at high temperatures than at low temperatures. . While this trial was a start in a useful direction, better control and more effective thermal management of catalytic converters is still needed to further reduce combustion emissions and to utilize the heat produced in catalytic converters. Disclosure of the Invention Accordingly, it is a general object of the present invention to provide a better heat management system of the catalytic converter to reduce and in some conditions to eliminate the time required to reach the temperature of freshly turned off in the catalytic converter systems of motorized vehicles while preventing excessive heat buildup during prolonged operating conditions. It is still another object of the present invention to provide adequate heat shielding around catalytic converters in motor vehicle exhaust systems to protect adjacent and near temperature sensitive materials and components for extended periods of hot operation. It is another object of the present invention to enable the safe discharge or dissipation of heat from catalytic converters in vehicle exhaust systems under conditions when there is excessive heat accumulation and temperatures threaten the continuous effective life of the catalytic converter. Another objective of this invention is to provide structures and methods to handle the heat generated in catalytic converters in useful and efficient applications. A more specific objective of this invention is to provide a controllable insulation and energy converter jacket for a catalytic converter that can be used to retain heat and maintain catalytic temperatures above the fresh off temperature for prolonged periods of time and decrease the time to reach the temperature of freshly turned off in conditions when the temperature of freshly turned off can not be maintained, protect the materials of the catalytic converter and surrounding components or environments from excessive heat and from temperature buildup, stabilize the operating temperatures of the catalytic converters and of other components of the exhaust system, and put the heat generated in the catalytic converters for more beneficial uses. Objectives, additional advantages and novel features of the invention will be disclosed in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by the practice of the invention. The objectives and advantages can be realized and achieved by means of the instrumentalities and in combinations particularly indicated in the appended claims. To achieve the foregoing and other objectives in accordance with the purpose of the present invention, as embodied and broadly described herein, an exhaust management system comprising variable and controllable insulation is provided around the catalytic converter that can be deactivated to maintain heat inside the catalytic converter when no gas is reacting in the catalytic converter or when the temperature of the catalytic converter is lower than the optimum temperature of just off, but it can be turned off when the temperature of the catalytic converter rises above the temperature of just turned off optimum The insulation can preferably also be maintained in a state or in. a variety of states between on and off to moderate the temperature in a catalytic converter assembly. The variable and controllable isolation can be a vacuum insulation with solid or gaseous conduction control capability to selectively enable or disable the insulator. A heat exchanger can be provided to conduct the heat away from the catalytic converter, and the heat exchanger can be jacketed by compact vacuum insulation to help retain heat over time when variable conductance insulation is activated. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated and form part of the specification, illustrate the preferred embodiments of the present invention, and together with the descriptions serve to explain the principles of the invention. Figure 1 is a schematic representation of a heat management system of a catalytic converter according to the present invention; Figure 2 is a cross-sectional view of a structured catalytic converter housing for providing heat management according to this invention; Figure 3 is a graphic illustration of the relationship between the time of oepration, temperature and emissions of conventional catalytic converter exhaust systems; Figure 4 is a graphic illustration of the relationship between the time of oepration, temperature and emissions of exhaust systems with catalytic converter for the administration of heat according to this invention in comparison with conventional catalytic converter systems; Figure 5 is a cross-sectional view of a catalytic converter heat management system embodying an alternate embodiment according to this invention; Figure 6 is an enlarged cross-sectional view of thermal shorting pins used to vary the thermal conductivity of the catalytic converter embodiments of Figure 2 or Figure 5; and Figure 7 is a cross-sectional view of an alternate embodiment in which a phase change material is placed in the inner housing surrounding the substrate with catalyst. BEST MODE FOR CARRYING OUT THE INVENTION A catalytic converter 10 constructed with a heat management system in accordance with this invention is shown in Figure 1 in an exhaust pipe P, which is connected to the multiple tubing M of a cooling machine. internal combustion E of a motor vehicle (not shown). the exhaust pipes P carry the combustion gases from the machine E to the catalytic converter 10, which can contain conventional three-way catalysts to react the fuel not consumed in the combustion gases and reduce the emissions of hydrocarbon, carbon monoxide, and nitrous oxides in the combustion gases. The reacted combustion gases are then discharged through an exhaust pipe T, usually at the rear end of the motor vehicle (not shown). Referring now to Figure 2, the catalytic converter * according to this invention comprises an internal catalyst housing 12, preferably made of metal or other material that is gas impermeable, to contain one or more catalyst substrates 14, 16 and 18, which may be ceramic material coated with three-way catalyst material, such as platinum, palladium, and / or rhodium. The combustion gases from the machine E (figure 1) flow through the catalytic converter 10, as indicated by the arrows 20 of figure 2, inclusive through the numerous small pores or channels 22 coated with catalyst that are formed in the ceramic substrates 14, 16 and 18 to increase the exposed surface area of the catalyst. The internal catalyst housing 12 is enclosed within an external housing 24 which is positioned at a spaced radially outward distance from the internal catalyst housing 12. The outer housing 24, like the inner housing 12, is preferably made of metal or other material that is impervious to gases even in a high-order hot vacuum environment. The annular chamber 30 enclosed between the inner housing 12 and the outer housing 24 is evacuated. The insulating performance of the chamber 30 is preferably controllably varied, as will be described in greater detail below. It is sufficient to say at this point that the insulating effect of the chamber 30 can be enabled to inhibit the transfer of heat from the catalyst substrates 14, 16 and 18 out of the inner housing 12 to the outer housing 24 to prevent it from dissipating into the surrounding environment, or it can be disabled to allow such heat to be transferred and therefore to "discharge" the heat of the catalytic reaction of the combustion gases in the surrounding environment. It can also preferably be enabled or disabled to vary the degrees between fully enabled or completely disabled, depending on the conductance or insulating capacity needed at any time. Therefore, the insulating chamber 30 can be enabled to retain the heat in the catalyst substrates 14, 16 and 18, for example when starting the machine, to shorten the time required for the catalyst to reach the optimum operating temperature of freshly turned off. It can then be disabled when the catalyst reaches an optimum operating temperature to avoid excessive heat buildup and high temperatures which could damage the substrates 14, 16 and 18 or shorten the life of the coated catalyst material on the substrates 14, 16 and 18. However, perhaps more importantly, the isolation chamber 30 can be enabled when the machine is turned off to maintain heat in the catalyst substrates 14, 16 and 18 as long as possible to maintain the temperature above the temperature of freshly turned off the catalyst until the next time the machine is ripped off, or at least to maintain the substrates 14, 16 and 18 above the ambient temperature to minimize the time it takes to raise the temperature of freshly extinguishing the catalyst the next time the machine is torn. Such variable conductance isolation and the methods and apparatus for controlling thermal transfer capabilities are illustrated1 and described in detail in our serial US patent application No. 07 / 960,885, which is incorporated herein by reference. Essentially, the vacuum chamber 30 is sealed from the interior of the inner housing 12 when the combustion gases flow through the catalyst substrates 14, 16 and 18, and is sealed from the outside environment with the outer housing 24. Exactly as Carrying out such a seal is not necessarily limited to any particular technique. However, for a long-lasting seal, it is preferred that the seal be made of metal-metal welding. For example, as illustrated in Figure 2, the housing 12 may comprise inner end plates 32 and 34 welded at opposite ends of a cylindrical side wall 36. The outer housing 24 similarly comprises outer end plates 38 and 40 welded to the opposite ends of the cylindrical side wall 42. The outer cylindrical wall 42 is kept separate from the cylindrical interior wall 36 by a plurality of spacers 50, preferably made of a material of low heat conductance, such as ceramic, formed with curved surfaces or trebles forming heat resisting nodes that minimize the areas of contact surfaces through which heat can be conducted from the inner housing 12 to the outer housing 24. For example, as shown in Figure 2, the spacers 50 can comprise spherical ceramic balls 44 placed between two curved ceramic liners 46 and 48, thus forming a series of "near points", that is, contact areas with very small surface, or nodes of thermal resistance between the inner housing 12 and the outer housing 24. Two of the thermal resistance nodes between are where the curved outer surfaces of the linings 46, 48 make contact with the respective cylindrical wall of the housing 36 and with the outer side wall 42. Two or more of the thermal resistance nodes are where the diametrically opposite sides of the spherical balls 44 make contact with the inner surfaces of the linings. respective 46 and 48. Of course, the curved liners 46 and 48 are not required, but these increase resistance to heat flow through the spherical balls 44. Also, the balls 44 could be elongated yarns and wound around the inner housing 12, but that configuration could provide a larger contact surface area. Ceramic spacers 50 are preferred over glass, porcelain, or other materials because ceramic can be made of materials that have high melting temperatures, which may be necessary to preserve the structural integrity in the high temperature environments generated by the catalytic reactions. The trajectories of combustion gases between the inner end plates 32, 34 and the outer end plates 38, 40 are preferably enclosed by tin foil ducts 52, 54 but impermeable to gases welded to the respective metal end plates 32, 38 and 34, 40 to maintain the vacuum-tight seal of the isolation chamber 30 between the inner housing 12 and the outer housing 24. The ducts 52, 54 are also preferably folded or corrugated as bellows to increase the effective distance that the heat it could have to travel in conduction from the inner housing 12, through the ducts 52, 54 to the outer housing 24. A plurality of tin reflective metal sheet radiation shields 56, which could be separated by the spacers 58, preferably made of ceramic, but not of a material significantly degassing, can be placed inside the chamber 30 to inhibiting the radioactive transfer between the housing 12 and the housing 24. The chamber 30 is evacuated to a high order vacuum, preferably in the range of 10"5 to 10" 6 torrs. for an insulating effect with highly effective vacuum. However, a vacuum isolation disablement system, such as the gas control system 60 illustrated in Figure 2, could be included to selectively enable or disable the insulating effect of the vacuum chamber 30. This gas control system 60, as described in our US Serial No. 07 / 960,885 patent application, may comprise a source of hydrogen gas, such as a metal hydride 62 and a hydrogene window or gate such as palladium 65, enclosed in metal containers respectively 66, 68, and connected via a circuit 70 to the vacuum chamber 30. When the metal hydride 62 is heated, for example by an electric heating element 72, gaseous hydrogen is made, which flows into the chamber 30. and conducts the heat through the chamber 30, thereby effectively disabling or extinguishing the insulating effect of the chamber 30. Then, when the metal hydride 62 is cooled, it is gaseous hydrogen is collected and a low pressure gradient is created in the container 66 which pulls back the hydrogen gas from the chamber 30, thereby re-enabling or activating the insulating effect of the chamber 30. The palladium gate 64 allows the hydrogen gaseous pass through when heated, such as by heating element 74, but is impermeable to hydrogen gas when it is not hot. Therefore, gaseous hydrogen, once introduced into the chamber 30 by heating both the metal hydride 62 and the palladium gate 64, can be retained within the chamber 30, even when the electrical power is turned off for the element heating 72, by also turning off the electrical power for the heating element 74 and letting the palladium gate cool down. In fact, the palladium gate 64 could be allowed to cool in a normal manner, before cooling the metal hydride 62, to substantially ensure that all the hydrogen is trapped in the chamber 30 for maximum isolation of the insulation by the gas control system . Then, when the insulation is to be turned on again, only the palladium gate 64 has to be heated momentarily to allow the gaseous hydrogen to be drawn from the chamber 30 through the palladium gate 64 and back into the metal hydride 62. Of course, the respective heating and cooling of the metal hydride and the palladium gate 64 can be controlled and timed to only partially enable or disable the gaseous heat conductance through the chamber 30 at any desired point and thereby vary or Control the heat transfer ratio on either side between full on and full off. The electric power to operate the gas control system 60 as described herein can be battery power, as indicated in 88. However, it is also an appropriate application for the use of thermoelectric or thermo-voltaic energy source devices using the heat generated by the catalytic converter. In fact, the output of sufficient heat from the catalytic converter to start producing some threshold level of electricity in such a thermoelectric or thermo-voltaic device could initiate and sustain the heat conductance of the insulation chamber 30. The heating elements 72, 74 can be ignited and shutting down by some appropriate electrical control system, such as respective relay switches 82, 84 controlled by an appropriate electronic control unit 86, such as a microprocessor or other logic circuit, such as could be good within the capabilities of persons with skill in the design and manufacture of electric control circuits, once the principles of this invention are understood. For example, the control unit 86 could include a timing capability connected to the ignition switch of the motor vehicle 76 or another circuit which indicates when the machine E(Figure 1) starts and then activates the relay switches 82, 84 to deactivate the isolation chamber 30 after an appropriate time interval which is set to allow the catalyst substrates 14, 16, 18 to reach the optimum operating temperature. Then, the control unit 86 can be programmed to turn on the insulating chamber 30 again, when the machine E is turned off, to retain the heat in the catalyst substrates 14, 16 and 18 for as long as possible during the time when Machine E is not working, instead of letting it cool quickly to room temperature. When controlled in this manner, the catalyst substrates 14, 16 and 18 can be maintained at temperature above the fresh off temperature for extended periods of time until machine E is turned on again, thus having the benefit of facilitating the reactions catalytic in the combustion gases almost immediately to reduce the dangerous emissions of combustion, instead of suffering the delay required to reach the temperature of freshly turned off again from the ambient temperature. These benefits will be illustrated by Figures 3 and 4. Referring first to Figure 3, curve 90 illustrates the relationship between engine operating time and catalyst temperature in a conventional catalytic converter (not shown), while the curve 100 illustrates combustion emissions of a conventional catalytic converter in relation to the operating time of the machine or motor and to the curve of the time-temperature profile 90. For example, in the operation of the conventional catalytic converter before the machine is turned on, the temperature of the catalyst, as indicated at 91, is essentially at room temperature T0. The ambient temperature T0, of course, may be above 100 ° F in the summer or be less than 0 ° F in the winter, but in any case it is below the typical TL temperature of freshly off 700-800 ° F. the catalysts of the state of the art. When the engine starts at an initial time, the combustion temperature is initially relatively cold, and the combustion gases are moist and rich in unburned fuel. Therefore, as illustrated in 103, the emissions of combustion gases Ec of the cold engine and the cold catalytic converter are very high during an initial heating period of 92. When the free temperature dr sparkle TL (approximately 600 ° -800 ° ) is finally reached in a time t2 after an initial heating period 92 (typically 60-180 seconds) driven by the heat in the combustion gases coming from the engine, the exothermic heat of the catalytic reactions with the gases in the catalytic converter drive the temperature upwards at a much faster rate, as indicated at 94, until the equilibrium operating temperature TR is reached at time t2. The temperature of freshly turned off TL, as indicated above, is defined as the temperature at which EL emissions have 50% of hydrocarbons converted by the catalyst. During this same time the interval of t ± a t2 (approximately 30-60 seconds), the catalytic reaction becomes much more effective, and the emissions rapidly decrease, as illustrated in 104, to an ER operation sphere, which be substantially as long as the machine is running. The specific operating temperature TR will of course depend on a number of factors, such as the fuel content in the combustion gases, the load of 1 engine and the volume of or combustion flow rate, catalyst effectiveness, and capacities heat dissipation of the catalytic converter, but it is intended to be high enough (approximately 649 ° C [1,200 ° F]) to catalyze the emission reduction reactions efficiently, but not so high to damage the catalyst, its substrates, or adjacent components or structures. When the engine shuts down, such as at time t2, the emissions, of course, end abruptly as indicated at 106, and the catalytic converter, including the catalyst, cools rapidly as indicated at 96, at room temperature T0 again at some time t4, which depends on many factors, such as environmental climate or other conditions, that the ambient temperature T0 is, and the structure and placement of the catalytic converter in the vehicle. However, generally, a typical conventional catalytic converter could be expected to cool down from the temperature of freshly turned off TL within about 20 to 40 minutes and close to the ambient temperature T0 in about 4 to 6 hours. Shaded area 108 under curve 100 represents all emissions during engine operation. Referring now to Figure 4, the time-temperature profile 110 corresponding to the time-emission profile 120 of a catalytic converter 10 (Figure 2) constructed in accordance with the present invention illustrates the administration of modified temperature and results in the improved emission reduction of this invention. The effectiveness of the insulating performance of the chamber 30 and the associated thermal storage elements according to this invention is sufficient to maintain the heat in the substrates of the catalytic converter 14, 16 and 18 (Figure 2) for up to 40 hours or more with less 2.27 Kg (5 pounds) of thermal storage material or heat sink, depending on the ambient temperature and other weather conditions. Therefore, unless the vehicle is not driven for a prolonged period of time, the catalyst temperature before the start at t0 will still be above the ambient temperature T0, and most likely very close to the temperature of freshly turned off TL as is illustrated in lll, if the engine E has been operated within the preceding twelve hours, which is typical of the use of most motorized vehicles used to commute between home and work. If the vehicle has been handled even more recently, such as within the past 10 to twenty hours, the isolation chamber 30 and the associated thermal storage elements will have maintained the substrates 14, 16 and 18 above the temperature of freshly turned off TL , as illustrated in 111 '. When the machine E (Figure 1) starts at a time t0, the catalyst already heated at 111 or 111 '(Figure 4) is already effective in catalyzing some exothermic reactions with combustion gases. Therefore, if the catalyst is not already at or above the freshly off temperature TL, it obtains it within a very short period of time t0 to tx in the order of approximately 60 seconds, as illustrated in 112. This period heating t0 to tx is shortened not only by having the catalyst already hot at the start time t0, but by the effectiveness of the insulation chamber 30 which confines the exothermic reaction and the heat of combustion in the catalyst substrates 14, 16 and 18 during heating. Therefore, the heating period of high emissions Ec, illustrated at 122, during the period from t0 to tx is also very short indeed much shorter than the period of high emissions Ec for conventional catalytic converters, as illustrated by curve 100, which is superimposed from figure 3 to figure 4 with dotted lines. The heating emissions are even less than that illustrated at 122 'when the engine is started with the catalyst temperature above the fresh-off temperature TL. Of course, once the TL temperature is reached at tlf the exothermic reaction increases the catalyst temperature very rapidly, as shown at 114, at an optimum operating temperature TR. At the same time the emissions decrease at a low level of ER operation, as illustrated at 124. At the optimum operating temperature TR, the gas control 60 (Figure 2) can be activated to disconnect the isolation chamber 30 to allow the dissipation of the excessive heat created by the exothermic catalytic reaction with the combustion gases within the environment surrounding the outer housing 24. When the motor is turned off, as at time t3, the emissions, of course, stop, as shown at 126. However, as soon as the motor E (figure 1) is turned off at time t3 (Figure 4), the gas control 60 (Figure 2) is actuated to activate the isolation chamber 30 again to prevent rapid cooling of the catalyst at room temperature T0. The much slower cooling of the catalyst with the isolation chamber 30 activated as illustrated at 116 in Figure 4, and as discussed above, the catalyst can be maintained above room temperature T0 for up to 40 hours or more. All emissions during operation of a motor vehicle equipped with a heat-managed catalytic system 10 in accordance with this invention is illustrated by the shaded area 128 under curve 120 in Figure 4. The relative reduction of emissions during start-up achieved by the catalytic converter with heat management 10 of this invention on the conventional catalytic converters can be seen by comparing the shaded area 128 under the curve 120, which represents the emissions of the catalytic converter 10 of this invention, with the shaded area 108 under the cave 100, representing emissions of conventional catalytic converters. Referring again to Figure 2, while the control unit 86 may be configured to deactivate the chamber 30 at some pre-set engine start time, which is preferably a sufficient time for the catalyst to reach the fresh temperature TL off, as described above, the other inputs and controls may also be used, as it might be within the capabilities of persons skilled in the art, once the principles of this invention are known. For example, an input of a temperature probe 78 in contact with the inner housing 12 could be used to activate the gas control 60, such as to deactivate the isolation chamber 30, when the temperature of the internal housing 12 reaches a certain temperature of operation. Of course, such temperature probe 78 would have to be well isolated from the environment and from the outer housing 24 to prevent heat conduction therethrough when the isolation chamber 30 is activated. It would also have to be sealed against leakage when it emerges through the outer housing 24, such as with similar ceramic connectors those described in our Serial US Patent Application No. 07 / 960,885. An alternate or additional temperature probe 79 at the downstream exhaust outlet 130 for measuring the temperature of the combustion gases emerging from the catalytic converter 10 could also be indicative of, even if not exactly the same, the temperature level of the catalyst, thus usable for driving the gas control 60. Such alternating temperature probe 79 at outlet 130 would not have to be insulated to prevent heat transfer or sealed to maintain vacuum, as would be required for the probe being extends through the isolation chamber 30. Other inputs, such as a temperature sensor 80 positioned adjacent the outer housing 24, could be used to activate or deactivate the isolation chamber 30. For example, if other components or structures (not shown) ) near the catalytic converter, 10 can withstand only such high temperatures, the temperature detector 80 could cause the control unit l will activate the gas control 60 to activate the isolation chamber 30 if the temperature of the heat 81 radiating from the external housing 24 goes above a pre-set level.

On the other hand, in other applications, it may be more important to "discharge" the heat from the inner housing 12 and the catalyst substrates 14, 16 and 18 faster than the disconnection of the isolation chamber 30 can be handled. thus, metal-metal contacts can be provided as thermal reservoirs or sinks between the inner housing 12 and the outer housing 24. For example, as shown in FIG. 2, one or more bimetallic dimples or activators 132, similar to those of those described in our Serial US Patent Application No. 07 / 960,885, on the side wall 36 of the inner housing designed to act from a normally concave configuration to an alternate convex configuration, as indicated by dotted lines 132 ', when the wall internal 36 reaches a predetermined maximum temperature. Thermal reservoir posts 134, preferably made of a good heat conducting metal, extend from the external wall 42 of the outer housing 24 in proximity sufficiently close to the respective bimetallic actuators 132 such that when the bimetallic actuators are bitten in their configurations convexes 132 ', these will make metal-metal contact with the posts 134. When such metal-metal contact is made, the posts 134 conduct heat very rapidly from the inner housing 12 to the outer housing 24, where it can dissipate it to the surrounding environment .

It would also be desirable in some circumstances or applications to improve the conduction of heat from the catalyst substrates, such as the bow-to-stern substrates 14, 18, to the wall of the inner housing 36 and inside the isolation chamber 30, such as when the substrates 14, 18 are made of ceramic materials that are poor heat conductors. Such improved conduction may be provided by one or more elongated pins 136, having one end extending within the substrates 14, 18 and the other end extending through the wall 36 of the inner housing and into the isolation chamber 30. If these pins are not long enough to make contact with the outer wall 42 so that there is no metal-to-metal heat conduction through them to the outer housing 24, these will still conduct heat towards the gaseous hydrogen inside the isolation chamber 30 when the insulating chamber 30 is deactivated by the gas control 60, as described above. < Alternatively, the pins 136 may be designed and positioned not to contact the outer housing 24 at low temperatures, but sufficiently elongate by thermal expansion to contact the external side wall 42 of the housing 24, as indicated at 136. 'in figure 6, at high temperatures. Once contact is made, as indicated at 136 ', the pins 136 become a thermal reservoir or short circuit to conduct the heat directly from the inner housing 12 to the outer wall 42 of the outer housing 24. To operate from this In this manner, the pin 136 is anchored in its middle section by welding 135 to the cylindrical wall 136. Therefore, as the heat rises, the pins 136 expand axially at both ends, as indicated by the dotted lines 136 'and 136. "in Figure 6. The heat required to cause sufficient expansion of the spigot 136 to make contact with the external side wall 42 as shown at 136 'can be designed on a pin 136 which takes such parameters into account as the length of the spigot 136 extending outward from the welded attachment 135 to the cylindrical wall 36, the type of metal or other material with which the spikes 136 are fabricated and their coefficient of thermal expansion mica, the openings between the ends of the pins 136 and the external side wall 42, and the like. The catalytic converter 10 can be designed and manufactured with a plurality of these pins 136 having different lengths or which are made of different materials with different coefficients of thermal expansion, so that not all of them make contact with the outer side wall 42 at the same time or at the same temperature to vary the number of thermal short circuits, thus varying all the thermal conductivity through the chamber 30. The pin 137 shown in the figure 6 is an alternative that extends only radially outwardly of the cylindrical wall 36 and not inward, so that it collects heat only from the cylindrical wall 36, which may be another design variation to establish a thermal short circuit. It may also be preferable, but not necessary, to provide additional heat control of radiation and convection by providing a heat absorbing material 138, as shown in Figure 2, in the path of the combustion gases to inhibit direct axial radiation from heat of the substrates 14, 16 and 18 outside the inner housing 12, as well as breaking the convection flows of the convection gases in that area. While the absorbent or heat-retardant material 138 is shown as a solid mallet structure in Figure 2, it could be a bulk material, such as ceramic wool fibers that do not opaque to infrared radiation, thus formed as multiple radiations between the fibers, thus retarding the escape heat by axial radiation. Ceramic wool fibers or other materials can also act to reduce the size of the convection cell, thus slowing the escape of heat by convection. While the retarder material 138 is shown only at the downstream end of the housing 12, a similar retarder could, of course, also be placed in the space immediately upstream of the first substrate 14.

For the most extensive heat and emission management according to this invention, an alternate mode 140 catalytic converter with heat storage and heat exchanger characteristics is illustrated in Figure 5. However, before proceeding with a detailed description of the catalytic converter 140, reference is again made again to FIG. 1. In this embodiment, the heat generated by the exothermic catalytic reactions is introduced with the combustion gases for beneficial uses, stored or dissipated, as appropriate for a variety of reasons For example, catalytic converter 140 produces heat and heats up much more quickly than a cold engine after starting, and a cold engine E not only does not run as efficiently as a hot engine, but also produces more harmful combustion emissions as well as also greater wear of the engine parts. In addition, the passenger compartments of most vehicles are heated with the engine's hot cooler, so there is no heat for passenger comfort or windshield defrosting until the engine E heats not only the same, but also the coolant inside the water jacket of the motor E. Therefore, according to this invention, the heat generated by the catalytic converter 140, instead of being wasted by dissipation into the atmosphere, can be collected in a head 142 and directed towards the water jacket of the engine E, as schematically indicated by dotted lines 144, to help heat the engine E more quickly, which in turn can get hot cooler to the passenger compartment heater H more quickly than via the hoses of the conventional heater indicated schematically by dotted lines 146. Alternatively or additionally, the heat generated by the catalytic converter or 140 can be taken directly to the passenger compartment, as schematically indicated by the dotted lines 148 for heating the seats S or to other components such as windshields, steering wheels, and space heaters, because the temperature in and immediately around of a working catalytic converter 140 are apt to be too high for standard engine coolant / antifreeze solutions, it is preferred to use a heat transfer and storage fluid 166 (Figure 5) in the heat exchanger chamber 164 having a higher boiling point and is more stable or the coolant / antifreeze solutions at such a high temperature. Accordingly, another heat exchanger interface 153 (FIG. 1) is provided to transfer moderate levels of heat and temperature to the coolant / antifreeze solution used in the vehicle's E engine. When no additional heat is needed, such as during the prolonged normal operation of the motor vehicle with the catalytic converter 140, the motor E via a connection 144, and other components already at their normal operating temperature, the heat generated in the catalytic converter 140 it can be directed to a heat storage sump 150, to a heat sink 152, or to the engine E via the connection 144 from where it can be dissipated together with the heat coming from the engine E in the atmosphere by the conventional radiator R of the vehicle . The plumbing, valves, controls and the like for various uses and components for the heat described above and shown in detail, because they are within the capabilities of people skilled in the art, once the principles of this invention be understood. Enough to say that, if the liquid motor cooler or other liquid medium is used to transfer heat, such a circulation circuit could comprise a conduit to send the liquid, another conduit to return the liquid, a pump, several valves, and controls that could be operated either manually or automatically by electricity, vacuum, or pressurized air. Also the heat storage tank 150 can be used to store heat for further use in heating the engine when starting or a cold passenger compartment, or the stored heat could also be used to help maintain a high temperature in the catalytic converter itself over longer periods of time. It can be, for example, a heat storage device such as that described in the article "Latent heat storage", published in February 1992 issued by Automotive Engineering, Vol. 100, No. 2, pages. 58-61. heat tubes, since they are not specifically shown in the drawings, could also be used in place of a transfer fluid to transfer heat to and from the catalytic converter. Referring now to Figure 5, the catalytic converter 140 according to this invention has the same basic components as the catalytic converter 10 described above, including, but not limited to, the three catalyst substrates 14, 16 and 18 contained within a catalyst. inner housing 12, a housing, an external housing 24 enclosing an insulating chamber 30, the gas control system 60, the metal-to-metal thermal deposition posts 134 and the associated bimetallic actuators 132, and radiation retardant material axial 138. However, the catalytic converter 140 also has at least one main heat exchanger 160 surrounding the outer housing 24 to collect heat from the external wall 36 and bring it to the manifold 142, (Figure 1) or other components or uses described above. The main heat exchanger 160 comprises an outer jacket 162 which extends radially outwardly from the outer end walls 38 and 0 of the outer housing 24 and which encloses a main heat exchanger chamber 164, which surrounds the external wall 36. The chamber 164 is constructed and sealed to contain a heat exchanger fluid 166, which may already be still liquid or a gas, preferably a fluid which is stable, and, if it were a liquid, which reached its boiling point, at the high temperatures that could normally be found in a catalytic converter, as described above. Such a heat exchanger fluid could be, for example, a polyether or a silicone. A plurality of fins 168 project radially outwardly from the outer wall 36 into the heat exchanger chamber 164 to increase the heat exchange surface area. Accordingly, when the insulating chamber 30 is activated, the heat transferred from the catalyst substrates 14, 16 and 18 and the inner housing 12 through the chamber 30 to the outer housing 24 is efficiently collected by the fluid 166 from the fins. 168. Fluid 166 can flow through heat exchange chamber 164, for example, into inlet 170 and exit outlet 172, to transport heat away from catalytic converter 140. Hoses or other appropriate plumbing fixtures ( not shown) can convey the hot fluid 166 to other components, such as the manifold 142, the heat reservoir 150, the heat sink 152, the heat exchanger 153, and the like, as shown in Figure 1 and It was explained above. Of course the inverse is also possible, that is, the fluid 166 can transport the heat from the heat reservoir 150 back to the catalytic converter 140, such as to pre-heat the catalyst substrates 14, 16 and 18 before starting the E. The jacket 162 of the main heat exchanger, as shown in Figure 5, is preferably manufactured with a very effective insulating material, such as the compact vacuum insulator (CVI) which is the essential material of our North American patent No 5,175,975, which is incorporated herein by reference. Consequently, when the insulating chamber 30 is activated, for example, when the motor is turned off, not only the hot internal housing 12 and the hot catalyst substrates 14, 16 and 18 are isolated by the highly effective insulating chamber 30, but the housing 24 it is also surrounded by the hot fluid 166 in the heat exchange chamber 164. The CVI 162 jacket is very effective in maintaining heat within the surrounding fluid 166, which further inhibits the transfer of heat from the catalyst substrates 14, 16 and 18. by keeping the gradient or heat differential very low through the insulating chamber 30. Several optional features of the catalytic converter 140 include secondary heat exchangers 174, 184 to recover the heat from the inlet 129 and from the outlet 130 of the exhaust pipe . As shown in Figure 5, the secondary heat exchanger 174 at the inlet 29 includes a jacket 176 enclosing a chamber containing fins 178 extending radially outwardly from the inlet 129. A heat exchange fluid, such as the same fluid 166 used in the main heat exchanger 160 can flow through the chamber from the fluid inlet 180 to the fluid outlet 182 to transport the heat coming from the fins 178 to other components for use, storage, or dissipation, as described above. Similarly, the secondary heat exchanger 184 at the exhaust outlet 130 has a jacket 186 that contains the fluid transfer means 166, which flows through the inlet 190 and the outlet 192 to transport the heat from the outlet. fins 188 to other components for use, storage or dissipation, as described above. The jackets 176, 186 in the secondary exchangers 174, 184 are not shown as comprising CVI, because these secondary heat exchangers do not perform the primary function of retaining heat in the catalyst substrates 14, 16 and 18, although these could be made of CVI to assist in that function or otherwise minimize the loss of heat to the surrounding atmosphere, if desired.

Another optional feature of the catalytic converter 140 illustrated in FIG. 5 is a heat deposit core 194 that extends through the centers of the catalyst substrates 14, 16 and 18. This solid heat storage core 194 serves two purposes. , first, causes the catalytic reaction of the combustion gases to occur in the outer parts of the substrates 14, 16 and 18, thereby minimizing the distance that the heat has to flow through the ceramic substrates 14, 16 and 18 to the inner housing 12, when the heat is transferred through the insulating chamber 30. Second, the heat deposit core 194 is preferably a material such as aluminum silicon or zinc magnesium which has a large capacity to deposit heat, so that receives and retains a large amount of heat during the operation of the catalyst. Then, when the motor E is turned off and the insulating chamber 30 is activated, the heat contained in the heat deposit core 194 helps maintain the temperature of the catalyst substrates 14, 16 and 18 for a still longer period of time. , enriching the probability that these will still be up or near the temperature of just turned off, or at least above the ambient temperature the next time the engine E is started. As in the catalytic converter mode 10 (Figure 2) described above, the controller 68 in Figure 5 can take the input signals from a variety of devices or detectors, such as the ignition switch 76, temperature detectors 80, 89 and the like, to initiate the operation of the gas control 60 to activate and deactivate the insulating chamber 30. For example, the temperature sensor 80 positioned adjacent the jacket 162 can detect when the environment around the catalytic converter 140 is becoming too hot and causes the controller to either activate the insulating chamber 30 or initiate the circulation of fluid 166 via a connection 196 to a pump control (not shown) or other appropriate vehicle or system components. A more remote temperature sensor 89 placed, for example, in the water jacket of the engine E or in the passenger compartment of the vehicle may introduce signals to the controller 68 to activate or deactivate the insulating chamber 30, the fluid circulation 66, and the similar. Several other optional signal inputs, represented by line 197, as well as optional signal outputs, such as to valves and other components, represented by line 198, may become obvious to persons skilled in the art once. that they have understood the principles and main characteristics of this invention. To further increase the thermal capacities of the catalytic converter, particularly to maintain sufficient heat stored for long periods of time to have available to heat the substrates 14, 16 and 18 to the fresh off temperature before starting the engine E, a quantity of material phase change (PCM), such as metals, metal salt hydrates or a hydride or trimethylol ethane (TME) or other polyhydric alcohols, described in U.S. Patent Nos. 4,572,864 and 4,702,853, both of which are incorporated herein by reference can be contained around or in relation to thermal flow with substrates 14, 16 and 18. For example, in mode 140 of Figure 5, instead of flowing transfer fluid 166 through the exchange chamber of Main heat 164, as described above, chamber 164 could be filled in instead of with a PCM, with or without the inlet and outlet fittings. 170, 172. As the heat is created by the catalytic reaction within the inner housing 12, the thermal conductance of the insulating chamber 30 is activated (the insulating effect is deactivated), as described above.NoR , to transfer the heat into the solid PCM 166 where it serves as the heat of fusion to melt the PCM and is stored in the same way as in the liquid PCM. Henceforth, if the PCM is supercooling or triprable, such as the aforementioned hydrates or hydrides, when the engine is turned off and the substrates 14, 16 and 18 are consequently cooled, the heat or fusion in the PCM liquid is retained although the PCM supercools down below its melting temperature, as described in U.S. Patent No. 4,860, 729 which is incorporated herein by reference. Finally, when the operator decides to start the engine E, a signal coming from the ignition switch 76 can activate a phase change trigger, such as the one described in the h American patent No, 4,860,729, which is also incorporated herein for reference . Such a phase change trigger, as indicated at 154 in Figure 1, may be connected to one of the attachments 170, 172 shown in Figure 5. When activated, the phase change trigger initiates the crystallization nucleation of the PCM thus causing it to obtain its melting point. With the conductance of the insulating chamber 30 also activated (the insulating effect disabled), the fusion heat of the PCM is conducted back into the internal housing 12 to the substrate 14, 16 and 18 to help them reach the temperature of just off. There are, of course, numerous other ways of using a PCM for these purposes, for example, the 150 heat store or another similar device could contain a PCM. The heat could also be transferred to and from a PCM container with a heat exchanger fluid 166. Still further, another chamber (not shown) could be positioned radially outwardly of the chamber 164 to enable the use of both a PCM and the thermal transfer fluid 166 surrounding the inner housing 12.

In another embodiment illustrated in Figure 7, a ceramic container 156 with an annular chamber 157 is positioned within the inner housing 12 and in surrounding relation with the catalyst substrates 14, 16 and 18. A phase change material 158, such as aluminum or almost aluminum alloy, but does not completely fill the annular chamber 157. As the patalizing substrate heats up during motor operation, the container 156 and the phase change material 158 are also heated, however, because the ceramic is a poor heat conductor, this container and the phase change material 158 do not take heat fast enough to increase the time required to heat the substrates 14, 16 and 18 to the fresh off temperature. However, the extra time, during the operation of the motor E, the material 158 within the chamber 157 will obtain sufficient heat to melt and heat substantially at the optimum operating temperature of the catalytic converter, as controlled according to the characteristics of this invention discussed above. The little padding mentioned above leaves enough space inside the chamber 157 to accommodate the expansion of the material 158 when it is heated, then, when the motor is turned off, the phase change material 158 will help to maintain the heat in the substrates 14, 16 and 18. The initial cooling is of a sensitive form, as discussed above for the core heat reservoir 194 in FIG. 5. However, when the temperature cools below the freezing point of the material 158, the temperature will remain constant for a prolonged period of time as the material gives up its heat of fusion. Consequently, when the composition of the material 158 has a freezing / melting temperature above the freshly extinguished temperature of the catalyst, the material 158 helps maintain the substrates 14, 16 and 18 above the fresh off temperature for an extended period of time. weather. While the description and exemplary application of this invention has been directed primarily to vehicles with internal combustion engines, it is not restricted to that application. Other applications can be, for example, in the chemical and petrochemical industries to control the temperature of reactors of catalytic processes. The above description is considered only illustrative of the principles of the invention. In addition, because numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and process as described above. Accordingly, all modifications and equivalents can be challenged to fall within the scope of the invention as defined in the claims that follow.

Claims (46)

1. CLAIMS l.- A combustion heat management apparatus, comprising: a catalytic converter and a substrate that provide structure and support surface for the catalyst to catalyze the oxidation or reduction reactions with contaminants in the combustion gases; a catalyst housing element for containing the catalytic converter element and for channeling the combustion gases to the catalytic converter element; and variable conductance insulating means surrounding the catalyst housing element to selectively isolate the housing member to inhibit heat transfer radially from the housing element in response to a first signal or to enable heat transfer in response to a second signal.
2. 2. The apparatus according to claim 1, wherein the catalyst housing element includes an internal metal side wall and the variable conductance insulator includes a metal enclosure surrounding the metal internal side wall and which is radially spaced apart. the exterior of the metallic internal side wall to enclose a main insulating chamber between the metallic internal side wall and the metal enclosure. 3. - The apparatus according to claim 2, wherein the main insulating chamber is evacuated to a high degree of vacuum, and wherein the variable conductance insulating means includes means for disabling the insulation connected to the main chamber to selectively disable the transfer of heat that inhibits the effect of the main isolation chamber in response to said second signal or to enable heat transfer that inhibits the effect of said main isolation chamber in response to said first signal. 4. The apparatus according to claim 3, wherein the isolating disabling means comprises gas supply means connected to the main isolation chamber for releasing gases within said main isolation chamber in response to said second signal or to recover gases from the main isolation chamber in response to said first signal. 5. The apparatus according to claim 4, wherein the gas supply means includes a metal hydride which releases hydrogen gas when it is heated and recovers the hydrogen gas when it is cooled. 6. The apparatus according to claim 5, wherein the gas supply means includes gate means placed between the metal hydride and the main isolation chamber to selectively pass or block the flow of gaseous hydrogen. 7. The apparatus according to claim 6, wherein the gate means comprises palladium, which allows the hydrogen to flow through it when it is heated and blocks the flow of hydrogen therethrough when it is cooled. 8. The apparatus according to claim 1, wherein the means of isolation with variable conductance are placed to inhibit heat transfer from the housing element when the combustion gases start to flow through said catalytic converter element, and wherein the second signal activates the variable conductance isolation means to enable heat transfer from the housing element after the combustion gases and said reactions raise the temperature of the catalytic converter element above the freshly off temperature . 9. The apparatus according to claim 8, wherein the first signal activates the insulation means with variable conductance to inhibit the heat transfer of the housing element when the combustion gases stop flowing through the converter element. catalytic. 10. The apparatus according to claim 9, including timer means for initializing the second signal. 11. The apparatus according to claim 9, which includes detector means for generating said second signal. 12. The apparatus according to claim 3, including heat activatable thermal trigger means positioned between the internal housing and the outer metal enclosure to make metal-to-metal contact between the inner housing and the external metal enclosure when the internal housing reaches a predetermined maximum temperature. 13. The apparatus according to claim 12, wherein the thermal reservoir element includes a bimetallic element that switches from a concave to a convex configuration when the temperature of the bimetallic element reaches said predetermined temperature. 14. The apparatus according to claim 1,2 wherein the thermal reservoir means includes a thermally expandable shank anchored in the inner housing extending radially outwardly to a sufficiently waxed position to the outer metallic enclosure to be thermally expandable in contact with said external metallic recitation. 15. The apparatus according to claim 3, wherein the means of isolation with variable conductance include a plurality of ceramic spacers between the internal side wall and the external metal recite, said spacers being formed only to form dots or semi-dots of contact with the internal side wall and with the external metal enclosure. 16. The apparatus according to claim 15, wherein the spacers include a spacer element with a rounded outer surface and a skin element with a curved outer surface positioned between the spacer element and each of the inner side wall and the external metal enclosure. 17. The apparatus according to claim 15, including at least one radiation shielding in said main isolation chamber between the side wall and the external metal enclosure. 18. - The apparatus according to claim 3, including a thermal conduction pin through the inner side wall within the catalytic converter element and inside the main isolation chamber. 19. The apparatus according to claim 18, wherein the pin is anchored to the inner side wall and is thermally expandable and shrinkable in and out of contact with said external metal enclosure as a function of temperature. 20. The apparatus according to claim 3, including flue gas inlet duct means extending between and separating the housing member and the external metal recirculation to conduct combustion gases within the internal housing member. , the inlet duct means include a corrugated tube made of tin foil welded at one end of the outer metal enclosure and at the other end to the inner housing. 21. The apparatus according to claim 3, including combustion gas outlet conduit means extending between and separating the inner housing element and the external metallic enclosure to conduct the combustion gases out of the housing element. In one embodiment, said outlet conduit means includes a corrugated tube made of metallic tin foil welded on one end to the inner metal housing and on the other to the outer metallic enclosure. 22. The apparatus according to claim 21, which includes radiation retardant means placed between the catalytic converter element and the outlet duct element to interrupt the radiation of the heat emanating from the catalytic converter towards the duct element of the catalytic converter. departure. 23. The apparatus according to claim 3, which includes radiation retardant means placed between the catalytic converter element and the outlet duct element to interrupt the heat convection from the catalytic converter to the outlet duct element . 24. The apparatus according to claim 23, wherein the convection retardant means include ceramic wool fibers. 25. The apparatus according to claim 3, including heat exchange means surrounding the outer metal enclosure to conduct heat away from or towards it. 26. The apparatus according to claim 25, wherein the heat exchanger means a sleeve positioned radially spaced apart to the outside of the metal enclosure and enclosing a main heat exchanger surrounding the outer metal enclosure to contain a fluid medium heat exchanger. 27. The apparatus according to claim 26, which includes a fluid inlet and a fluid outlet for conducting the fluid heat exchanger medium in and out of the main heat exchanger chamber. 28. The apparatus according to claim 27, wherein the outer jacket comprises a compact vacuum insulation that includes two hard, but foldable sheet metal sheets placed in closely spaced relation to each other and sealed around their edges of each one. by metal-metal welders to form a vacuum chamber therebetween, said chamber is evacuated at a pressure at least as low as 10"s torr and a plurality of low heat conducting spacers between said sheets to maintain said spacing. 29. - The apparatus according to claim 27, including a heat sink thermal storage device connected in fluid relationship with the chamber of the main heat exchanger. 30. The apparatus according to claim 27, which includes heat dissipating means connected in fluid relation with the chamber of the main exchanger to dissipate the heat conducted from the metallic recirculation to the fluid medium. 31. The apparatus according to claim 27, which includes fluid conducting means that connect to the chamber of the main heat exchanger with a heat exchanger cooling the engine to transfer the heat to a water jacket in a combustion machine internal that produces the combustion gases. «32. The apparatus according to claim 3, including heat storage means surrounding the external metal enclosure for storing the heat generated in the internal housing element. 33. The apparatus according to claim 32, wherein the thermal storage means comprises a phase change material. 34.- The apparatus according to claim 32, which includes trigger means selectively operable to selectively initiate the nucleation of the phase change material. 35. The apparatus according to claim 1, including thermal storage means that in the catalyst housing element in contact with said substrate to store the heat generated in the catalyst housing element. 36.- The apparatus according to claim 36, wherein the thermal storage means comprises a phase change material. The apparatus according to claim 36, which includes a secondary heat exchanger connected to the flue gas inlet duct element to take the heat from the combustion gases before the latter reach said substrate. 38.- The apparatus according to claim 21, including a secondary heat exchanger connected to the flue gas inlet duct element to take the heat from the combustion gases before the latter have gone through said heat exchanger. substrate 39.- A method to administer heat in a catalytic converter comprising the steps of: surrounding the catalytic converter with thermally variable insulation material that can vary between "activated" to inhibit heat transfer and "deactivated" to enable the transfer of heat. hot; activate the variable thermal insulation when no combustion gas is reacting inside the catalytic converter to retain the heat in the catalytic converter, - leave the variable thermal insulation activated when the temperature of the catalytic converter is lower than the temperature of the newly extinguished catalytic converter; deactivate the variable thermal insulation when the temperature of the catalytic converter is higher than the temperature of the newly switched off. The method according to claim 39, which includes the step of controlling the thermal insulation between fully activated and completely deactivated when the variable thermal insulation is deactivated in a fluid medium and transferring the heat to another component. 41. The method according to claim 40, which includes the step of recovering the heat generated by the catalytic converter when the variable thermal insulation is deactivated in a fluid medium and transferring the heat to another component. 42. The method according to claim 41, which includes the step of transferring the heat in the fluid medium to the engine that produces the combustion gases. 43.- The method according to claim 41, which includes the step of transferring the heat in the fluid medium to a thermal storage device. 44. The method according to claim 43, which includes the step of transferring the heat from the thermal storage device back to the catalytic converter before starting the engine that produces the combustion gases when the temperature of the catalytic converter is lower than the temperature of freshly turned off. 45.- The method according to claim 41, which includes the step of transferring the heat in the fluid to the passenger compartment of a motorized vehicle that is energized by that machine that produces the combustion gases. 46. The method according to claim 41, which includes the step of transferring the heat in the fluid to a heat sink to dissipate the heat in the atmosphere. EXTRACT A catalytic converter is surrounded by variable conductance insulation to keep the operating temperature of the catalytic converter at an optimum level, to inhibit heat loss when it reaches the temperature of the catalytic converter at the temperature of just off, to store the excess heat to maintain or accelerate the temperature range of freshly turned off and to drive excess heat away from the catalytic converter after reaching the temperature of just off. Variable conductance isolation includes vacuum gas control and metal-thermal thermal firing mechanisms. Radial and axial shielding inhibits heat loss by radiation and convection. The thermal storage medium includes phase change material, and heat exchanger chambers and fluid that carry the heat from the catalytic converter. DAÜ