CA2603756A1 - Heat shield configuration - Google Patents
Heat shield configuration Download PDFInfo
- Publication number
- CA2603756A1 CA2603756A1 CA002603756A CA2603756A CA2603756A1 CA 2603756 A1 CA2603756 A1 CA 2603756A1 CA 002603756 A CA002603756 A CA 002603756A CA 2603756 A CA2603756 A CA 2603756A CA 2603756 A1 CA2603756 A1 CA 2603756A1
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- CA
- Canada
- Prior art keywords
- heat shield
- closure
- configuration according
- opening
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R13/00—Elements for body-finishing, identifying, or decorating; Arrangements or adaptations for advertising purposes
- B60R13/08—Insulating elements, e.g. for sound insulation
- B60R13/0876—Insulating elements, e.g. for sound insulation for mounting around heat sources, e.g. exhaust pipes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R13/00—Elements for body-finishing, identifying, or decorating; Arrangements or adaptations for advertising purposes
- B60R13/08—Insulating elements, e.g. for sound insulation
- B60R13/0884—Insulating elements, e.g. for sound insulation for mounting around noise sources, e.g. air blowers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L59/00—Thermal insulation in general
- F16L59/08—Means for preventing radiation, e.g. with metal foil
Abstract
The present invention relates to a heat shield configuration having a heat shield for shielding an object from heat and/or noise having an internal surface facing toward the object and an external surface facing away from the object as well as an opening, which goes through the heat shield having internal surface and external surface. The heat shield has a closure for at least regionally closing the opening. In addition, an actuating device is provided, which is implemented to open and close the closure as a function of a controlled variable relevant for the function of the object.
Description
Reinz-Dichtungs-GmbH
D.P 230 CA
TO/sk HEAT SHIELD CONFIGURATION
[00011 The present invention relates to a heat shield configuration having a heat shield for shielding an object against heat and/or noise having an internal surface facing toward the object and an external surface facing away from the object as well as at least one opening, which goes through the heat shield having internal and external surfaces. Heat shields of this type are used, for example, in engine compartments of motor vehicles, in particular in the area of the exhaust system, to protect neighboring temperature-sensitive coinponents and assemblies from impermis-sible heating. The heat shields are often used simultaneously as a noise protector. Concretely, such heat shields may be used, for example, for shielding a catalytic converter or pre-catalytic converter, a particulate filter, or other components in the area of the exhaust system or of a tur-bocharger. In regard to continuous operation, it is often not only important for these components to be protected from too strong a temperature strain, but rather the operating temperature is to be subjected to strong oscillations during the entire operating life as little as possible.
D.P 230 CA
TO/sk HEAT SHIELD CONFIGURATION
[00011 The present invention relates to a heat shield configuration having a heat shield for shielding an object against heat and/or noise having an internal surface facing toward the object and an external surface facing away from the object as well as at least one opening, which goes through the heat shield having internal and external surfaces. Heat shields of this type are used, for example, in engine compartments of motor vehicles, in particular in the area of the exhaust system, to protect neighboring temperature-sensitive coinponents and assemblies from impermis-sible heating. The heat shields are often used simultaneously as a noise protector. Concretely, such heat shields may be used, for example, for shielding a catalytic converter or pre-catalytic converter, a particulate filter, or other components in the area of the exhaust system or of a tur-bocharger. In regard to continuous operation, it is often not only important for these components to be protected from too strong a temperature strain, but rather the operating temperature is to be subjected to strong oscillations during the entire operating life as little as possible.
[0002] The most possible constant operating temperature is advantageous, for example, for the components used for exhaust treatment, because in this way a more uniform exhaust treatment effect may be achieved. Simultaneously, the service life of the components, neighboring housing parts, and gas-conducting components may also be lengthened. Rapid heating and keeping the operating temperature constant are of special significance in regard to maintaining the future EU
exhaust gas standard Euro 5. In addition to the exhaust gas limiting values in the normal operat-ing phase of an engine, exhaust gas limiting values of the cold starting phase are also incorpo-rated here., The efficiency of the exhaust treatment catalytic converters for the pollutants con-taineci in the exhaust gas is known to differ as a function of the temperature. Thus, for example, the discharge of hydrocarbons and carbon monoxide is particularly high at the beginning of the cold start phase. This is primarily to be attributed to the fact that the catalytic converter has not yet reached its operating temperature. To reduce these pollutants, it is therefore necessary to in-crease the operating temperature of the catalytic converter as rapidly as possible. On the other hand, the operating temperature cannot rise too much, however, because this results on the one hand in the increase of other pollutants sucli as nitrogen oxides in the exhaust gas, and on the other hand, too high a temperature may damage the catalytic converter itself.
[00031 In other cases, it may be desirable, for example, to be able to set a higher or lower tem-perature during a specific operating phase than in other operating phases.
Thus, for example, a particulate filter may pass through an operating phase of higher temperature in wliich accumu-lated particles in the particulate filter are removed by oxidation. Up to this point, reaching this elevated temperature by engine measures or by additional injection of fuels was typical. After completed particle reinoval, the measures were returned to normal operation again. However, this procedure is very complex and requires additional energy.
[0004] In consideration of the problems described above, it is the object of the present invention to specify a heat shield configuration which is capable of setting the operating temperature of an object shielded thereby to a predefined range. The heat shield configuration is on the one hand to allow the temperature to be kept as constant as possible and simultaneously ensure the most rapid possible achievement of the operating temperature. On the other hand, the heat shield con-figuration is also to allow selective operation at various predefined temperatures.
[00051 This object is achieved by the heat shield configuration according to Claim 1. Preferred embodiments are specified in the subclaims.
[0006] The heat shield configuration according to the present invention comprises a heat shield for shielding an object against heat and/or noise having an internal surface facing toward the ob-ject and an external surface facing away from the object. An opening is provided in the heat shield, which goes through the internal and external surfaces. According to the present invention, this opening is at least regionally closable by a closure, which may be opened and closed using an actuating device as a function of a controlled variable relevant for the function of the object.
[00071 The opening iinplemented in the heat shield is exposed by opening the closure, so that better temperature regulation is made possible by the passage thus resulting.
For example, hot air accumulated between the object to be shielded, which is situated neighboring the internal surface of the heat shield, aiid the heat shield may escape througli the exposed opening and tlius the tem-perature in the area around the object to be shielded may be reduced. Vice versa, it is just as pos-sible, for example, to introduce colder air in the direction toward the object to be shielded through the exposed opening and thus reduce the temperature in its environment. It is also possi-ble to feed hot air in the direction toward the object to be shielded through the opened opening or discharge cold air if its temperature increase is desired. In addition, the opening may be at least partially closed in an operating phase of increased temperature, while it is at least partially ex-posed in an operating phase of lower temperature, so that accumulated heat may escape througli the opening. More than two operating phases of different temperatures are also fundamentally settable as a function of the opening size of the opening.
[0008] At least one of the following measured variables comes into consideration as a controlled variable which the closure is opened or closed as a function of:
- a temperature, - a pressure, - a velocity, - an acoustic signal, - an exhaust gas value, - a volume flow, and - an operating time.
[0009] In the preferred application of the present invention in the area of internal combustion engines, very generally, those measured variables which may be measured in the area of the in-ternal combustion engine come into consideration.
[0010] The temperature is expediently a temperature in the environment of the object to be shielded or :he component temperature of the object or another component, if this temperature has effects on the function of the object to be shielded, By measuring the temperature, it may be established directly whether the object to be shielded is threatened with overheating. If so, the actuating device may counteract this by opening the closurc in the heat shield. Vice versa, in the event of too strong cooling, the closure may be closed again using the actuating device.
[00111 The internal pressure of the object to be shielded may particularly be measured as the pressure. A possible application is in particulate filters, in which the internal pressure rises witli increasing charging by particles. The throughput correspondingly worsens, and the particulate filter must be freed of the deposited particles to obtain the desired filtering action. This may be performed by raising the temperature in the interior of the particulate filter so strongly that the particles oxidize and are blown out of the filter. The required temperature increase may be per-formed or at least supported by closiiig the closure, by which heat accumulates in the area of the heat shield around the particulate filter. After passage of a predefined time or altematively upon reaching a lower internal pressure, which allows regular operation of the particulate filter, the closure may be opened again, so that the operation runs at the desired filter operating tempera-ture.
[0012] To be able to operate the object to be shielded at a desired operating temperature - as noted - the temperature of the object itself may be measured directly or in its enviromnent. In-stead of the temperature, however, other measured variables may also be measured, which have effects on the operating temperature of the object. Such a parameter is, for example, a flow which may result in cooling if it flows along the object to be shielded. The closure may thus be closed more in the event of stronger flow and opened more in the event of lesser flow as a func-tion of the flow velocity to set a desired operating temperature. If the object is moved during op-eration, the travel velocity may also be measured instead of a flow velocity.
[0013] Acoustic signals may be ascertained if the object, which produces noise itself, is to be shielded to the environment. In the event of stronger noise development, the closure is expedi-ently closed. The noise pressure is preferably measured.
[0014] Exhaust gas values may also be used as measured variables. For example, concentrations of one or more gases in the exhaust gas may be determined in a way known per se. As noted at the beginning, the effectiveness of the catalytic converter for the various pollutants changes as a function of the temperature. The measurement of the exhaust gas value for these pollutants thus allows conclusions as to whether the temperature is in the desired range. If the irieasured exhaust gas values deviate from predefined setpoint values, the exhaust treatment action may be brought back into the setpoint range by temperature correction.- This is performed according to the pres-ent invention, for example, by opening or closing the closure and correspondingly regulating the opening cross-section of the opening in the heat shield as a function of one or more measured values of the pollutant concentration in the exhaust gas.
[0015] In addition to the cited measured variables, in principle, all those measured variables come into consideration which may have an influence on the function of the object to be shielded or contain information about the operating state or another property of the object. The actuating device may act as a function of only one measured variable or also as a function of multiple measured variables.
[0016] To measure the measured variable, the heat shield configuration according to the present invention expedicntly comprises at least one suitable measuring device. The measuring device may fundamentally be a typical device from the prior art for measuring the particular measured variable. For example, a temperature sensor may be used for temperature measurement, which is attached to the object to be shielded, the heat shield, or another point in proximity to the object.
Analogously, other sensors (pressure, noise pressure, electrochemical value) may be used, which are already known in the prior art. Ideally, sensors which may be replaced independently of other parts are used. In many cases, measuring devices already present in the overall device which comprises the heat shield configuration according to the present invention, such as measuring devices for measuring exhaust gas values or vehicle velocities, may also be used.
[0017] The heat shield configuration expediently also comprises means for analyzing the meas-urement results and control means for controlling the actuating device on the basis of the analy-sis of the measurement result. Both means may be spatially combined in one device and may be situated separately from or integrated in the actuating device. In each case, these are components known per se, which do not have to be described in greater detail here. As already for the meas-uring device, means present in any case in the overall device may also be used for the analysis and control rneans.
[0018] The actuating device may, for example, be a pneumatic, hydraulic, or electrical actuating device. Preferably, a seivomotor is used as an electrical actuating device or a vacuuni unit is used as a pneumatic actuating device. The connection between actuating device and closure is funda-mentally arbitraiy. For example, a push rod or pull rod may be used.
[0019] The opening may either be a through opening in the heat shield or also an opening in an external edge area of the heat shield. Both variants may also be combined with one another in one heat shield. The possibility which is selected is also a function, inter alia, of the available space on the heat shield. The shape of the opening is fundamentally arbitrary and is also primar-ily a function of the available space. The size of the opening is selected as a function of the re-quired heat exchange and/or in regard to the desired noise insulation. The required opening cross-section may be implemented using one or more openings.
[0020] The closure may fundamentally have any arbitrary shape which is capable of closing the opening in the heat shield to the required extent. It may be inserted fitting into the opening or may be situated on the heat shield covering the opening. The way in which the closure exposes the opening is also fundamentally arbitrary. For example, the closure may be displaced laterally in relation to the opening and/or pivoted and/or lifted like a flap off the opening. In the two first cases, the closure is preferably displaced and/or pivoted predominantly parallel to the external surface of the heat shield using a slide. In the latter case, the closure may fundamentally open toward any side of the heat shield. However, for space reasons it is fiequently expedient for the closure to open toward the side of the external surface of the heat shield, because there is fre-quently insufficient space on the side of the internal surface between heat shield and object to be shielded. The flap may also comprise multiple lamellae, which may be opened or closed indi-vidually or jointly. The material of the closure may be selected arbitrarily.
The closure preferably comprises the same material as the heat shield. The closure is fastened to the heat shield de-pending on the type of actuation, for example, using hinges in the case of a flap closure, a screw or rivet connection, which simultaneously provides the rotation point, in the case of a rotating slide, or using guide rails in the case of a slide. A flap closure may possibly also be fastened to an object in proximity to the heat shield and not to the heat shield itself [0021 ] A preferred application of the heat shield according to the present invention is, as already noted, the shielding of components in the area of an internal combustion engine and in particular in the area of the exhaust system. In these applications, the danger primarily exists that the object to be shielded will overheat as a result of the accumulated heat in the area of the heat shield. To prevent this, the heat shield according to the present invention is expediently impleinented in such a way that the closure is opened if a specific limiting temperature is exceeded, so that the accumulated heat may escape from the area between heat shield and object to be shielded. As long as the components situated in the area of the heat shield have not yet reached their operating temperature, however, the accumulation of heat in the area of the heat shield is completely ad-visable, so that the components may reach their optimal operating temperature as rapidly as pos-sible. For this reason, the heat shield according to the present invention is preferably designed in this variant in such a way that the closure remains closed until reaching the limiting temperature.
The teinperature does not have to be measured directly, as noted, but it may be a measured value other than the temperature.
[0022] A further preferred application is the shielding of particulate filters, in particular diesel particulate filters. As described, it may be expedient here to remove the accumulated particles by oxidation at increased temperature in a specific operating phase. Using the heat shield according to the present invention, the required temperature increase may be achieved especially easily and rapidly. In contrast to the prior art, it is frequently no longer necessary to increase the exhaust gas temperature by additional engine measures, although this still remains possible. Rather, the opening in the heat shield may be closed by closing the closure using the actuating device. The temperature then rises in the area of the heat shield and thus also in the particulate filter. If this temperature increase alone is insufficient to begin the oxidative cleaning, in addition, the fuel/air mixture of the engine may be adapted or fuel may be injected directly, as usual. After coanpleted cleaning, the closure is opened again, the additional altered injection is ended if necessary, and the temperature in the area of the heat shield falls again, so that the particulate filter may operate further in the regular operating state.
[0023] gn the case of the heat shield for a particulate filter or a similar device, the closure is ex-pediently opened at lower temperature and closed at increased temperature.
This is preferably reversed for the heat shield described for a catalytic converter. The closure is closed with sinking teniperature here, while it is opened in the event of temperature increase.
Botli variants may be implemented corresponding to the requirements in the scope of the present invention. They may also be used jointly in the same heat shield. Moreover, in a heat shield for a particulate filter, aii additional higher temperature limit may be defined to make the closure open in order to prevent overlaeating of the particulate filter.
[0024] It is not absolutely necessary for the closure to open suddenly if the predefined limiting value is exceeded, for example, and expose the opening 100 %, while the closure is immediately completely closed and completely covers the opening at a value of less than or equal to the lim-iting value. Rather, it is also possible that the opening and closing of the closure occurs within a predefined limiting measured value interval. For example, it may be advisable for the closure to increasingly expose the opening with increasing deviation from the predefined limiting value, so that, for example, with increasing temperature (with more strongly deviating measured value), an increasing temperature exchange with the environment is possible. Vice versa, the opened clo-sure may be increasingly closed again if the increased temperature (or another measured value) falls in the direction toward the limiting value again. In this way, a continuous temperature con-trol adapted to the ambient temperature (or the relevant measured value) is possible, which al-lows the object to be shielded by the heat shield to be kept at an essentially constant operating temperature which is optimal for this object. Closing the opening does not have to result in a hermetic seal of the opening. A significantly reduced temperature exchange in relation to the opened state is generally sufficient. The above statements also apply for the case of opening upon sinking (temperature) measured value and closing upon higher (temperature) measured value.
[0025] The range in which the limiting measured value is set, in which the closure in the heat shield configuration according to the present invention opens or closes, is mainly a function of the temperature at which the object which is to be shielded using the heat shield according to the present invention is to be kept. In the case of catalytic converters, this is expediently the tein-perature at which the best exhaust gas reduction is possible. For particulate filters, on the one hand the optimal temperature for particle filtration and on the other hand the best temperature for oxidative removal of the particles in the particle removal phase may be set.
This particular opti-mal operating teinperature may be achieved very rapidly using the heat shield configuration ac-cording to the present invention, because heat may be accutnulated in the area around the object to be shielded in the warm-up phase by closing the opening using the closure, so that the object heats rapidly. On the other hand, exceeding an optimal operating teinperature too strongly may be prevented by setting the limiting measured value appropriately, upon exceeding which the closure in the heat shield is opened and thus exposes the opening entirely or partially depending on the measured value. Heat accuinulated between heat shield and object to be shielded may es-cape tlirough the exposed opening. Additionally or alternatively, it is possible to inject cool air through the opened opening in the direction toward the object to be shielded (such as the cata-lytic converter, particulate filter, etc.), to cool it.
[0026] Especially good regulation of the temperature in the area between heat shield and object to be shielded is possible if in addition to the first opening having the first closure at least one further opening is provided, which is also closable using a closure to be opened and closed as a function of a measured variable relevant for the function of the object to be shielded. This meas-ured variable may, but does not have to be the same measured variable as for the first closure.
[00271 The further closure may fundamentally be implemented as described above. It may also be opened and closed by an actuating device, as was described above. However, it is also possi-ble to leave out the actuating device and use a closure opening and closing automatically as a function of a measured variable. This is preferably a closure opening and closing as a function of the temperature. The closure therefore expediently has a bimetallic element, which deforms as a function of the teinperature. The bimetallic element may be a part of the closure which deforms in relation to the opening, or a separate part which works together with a slide, rotating slide, or flap and displaces it in relation to the opening.
[00281 The presence of at least one further closure and an opening closable thereby has the ad-vantage that the temperature in the area between heat shield and object to be shielded may be set even more precisely. For example, it is possible to implement the actuating device(s) and clo-sures in such a way that the latter open in sequence if various limiting measured values are ex-ceeded. This may be achieved by storing various limiting measured values and corresponding diftering activation of the closures. The closures may be opened in sequence, for example, in such a way that the exposed total opening cross-section of the openings rises with increasing temperature, so that increasingly more hot air may escape through the exposed operiing. Over-heating may thus be prevented even in the event of very strongly rising temperatures.
[0029] A ftirther advantage which may be achieved by providing multiple openings closable us-ing a closure is that targeted flow guiding is possible in the space between heat shield and object to be shielded. For exainple, cooler air may be introduced in the direction toward the object througli one or more of the exposed openings if the closure is opened, while heated air flows out through the remaining openings. The openings and closures on the heat sliield are expediently oriented in such a way that the hot air flowing out is not directed toward temperature-sensitive par,s situated in the surroundings of the heat shield. Ideally, the hot exhaust air is directed in such a way that it is fed to an external flow existing in the area around the heat shield and is con-veyed thereby. It is also advantageous if the cooler air introduced into the area between heat shield and object to be heated is fed from this external flow existirig in the area around the heat shield.
[0030] As already described above, it is also possible in the case of feeding cooler air into the area between heat shield and object to be shielded that various closures open for the feeding of cooler air at different temperatures. This is also fundamentally true for the closures through which the heated air flows out. In this way, a very constant temperature may be ensured in the area between heat shield and object to be shielded over a large temperature range. Additionally or alternatively to these measures, it is also possible that the closures for the feeding of cooler air open at a different temperature than the closures for the exhaust of heated air. In the latter case, it is preferable for the feed closures to open at a somewhat higher temperature than the closures for the exhaust of hot air.
[00311 The heat shield according to the present invention is not restricted to special shapes or sizes. For example, it may be a planar heat shield, which is attached above the object to be shielded, so that hot air accumulates below the heat shield. The present invention is especially suitable for a heat shield which essentially encloses the object to be shielded on all sides. A com-parable effect may also be achieved if a heat shield opeti on one side is closed by an adjoining component. The object to be shielded is thus largely encapsulated by the heat shield md possibly other components. This typically does not represent a hermetic enclosure, because hermetically terminated passages for supply lines and drain lines are typically not provided in the heat shield.
Nonetheless, the heat exchange with the environment is relatively restricted in these cases, so that overlieating of the components encapsulated in the heat shield may occur very rapidly. On the other hand, the cold start phase is relatively short, because the desired operating temperature is achieved rapidly by the heat retention inside the heat shield. This optimal operating tempera-ture may be kept constant in a desired range easily using the heat shield configuration according to the present invention by the provision according to the present invention of at least one open-ing which is closable by a flap opening and closing as a function of a measured variable. The at least one heat shield, which essentially completely encloses the object to be shielded, addition-ally ensures especiaily good noise insulation.
[0032] The measures suggested according to the present invention may be implemented easily and cost-effectively without additional complicated measures or components in typical heat shields. The main bodies of the heat shield according to the present invention may thus funda-mentally correspond in their implementation to those whicli are already known from the prior art.
Size, shaping, and materials thus correspond to the prior art. Heat shields in sandwicli construc-tion, which comprise two outer layers typically made of inetallic material and an insulating layer embedded between them, are preferred. The surfaces may be smooth, textured, or perforated.
Heat shields of this type are described, for example, in DE 3834054 Al and EP
1775437 Al (European Patent Application 05022095.3) of the applicant. Furthermore, reference may be made to GB 2270555 A and US 2004/0142152 Al.
[0033] The present invention may fundamentally be applied to all heat shields of the prior art.
The present invention is especially suitable for those heat shields which are used in the area of high temperature development and for shielding those objects which may be damaged by excess temperature. A preferred use of the heat shields according to the present invention is therefore in the area of internal combustion engines and particularly in the area of the exhaust system here.
Examples of preferred heat shields are those for catalytic converters, pre-catalytic converters.
diesel particulate filters, or also turbochargers. The present invention may additionally be applied in particular to metallic subfloors or their components in the area of an exhaust system.
[0034] The present invention is explained in greater detail in the following on the basis of drawings. These drawings are exclusively used to illustrate preferred exemplary enlbodiments of the present invention, without the present invention being restricted thereto.
Identical parts are provided with identical reference numerals in the drawings.
[0035] In the figures:
Figure 1(a): schematically shows a cross-section through a first exemplary embodiment of a heat shield configuration according to the present invetYtion for shielding a cata-lytic converter having closed closure;
Figure 1(b): schematically shows the heat shield configuration from Figure 1(a) having opened closure;
Figure 2(a): schematically shows a cross-section tlu-ough a second exemplary embodiment of a heat shield configuration according to the present invention for shielding a cata-lytic converter having two closed closures;
Figure 2(b): schematically shows the heat shield configuration from Figure 2(a) having one open and one closed closure;
Figure 2(c): schematically shows the heat shield configuration from Figure 2(a) having two open closures;
Figure 3(a): schematically shows a cross-section through a third exemplary embodiment of a heat shield cc,iiiguration according to the present invention for shielding a cata-lytic converter having one closed closure, the heat shield being open on one side;
Figure 3(b): schematically shows the heat shield configuration from Figure 3(a) having open closure;
Figure 4: schematically shows a block diagrant to explain the activation of aii actuating de-vice:
Figure 5: schematically shows a partial cross-section tlirough a further exemplary embodi-ment of a heat shield configuration according to the present invention in the area of a closure;
Figure 6: scheinatically shows a top view of a further exemplary enibodiment of a heat shield configuration according to the present invention and a catalytic 'converter thus shielded, and Figure 7: schematically shows a top view of still a furtlier exemplary embodiment of the heat shield configuration according to the present invention and a catalytic con-verter thus shielded.
[0036) Figures 1(a) and 1(b) show a first exemplary embodiment of a heat shield configuration according to the present invention having a heat shield 1, wliich is used for shielding a catalytic converter 2 situated in the interior of the heat shield 1. The catalytic converter 2 may be, for ex-ample, a catalytic converter for treating exhaust gases of an internal combustion engine of a mo-tor vehicle. The exhaust treatment action of the catalytic converter 2 is best within a specific temperature range. This temperature range is to be reached as rapidly as possible, but is not to be exceeded. The catalytic converter 2 is enclosed essentially completely and on all sides by the heat shield 1. In this way, the catalytic converter 2 and its enviromnent are insulated especially well from one another in regard to temperature influences and noise. In addition, the encapsula-tion is used so that the catalytic converter 2 reaches the operating temperature required for opti-mal exhaust treatment rapidly. The cold start phase may thus be shortened by rapid teinperature increase in the interior of the heat shield 1, which is a significant advantage in regard to the ex-pected exhaust gas standard Euro 5.
[00371 Figure 1(a) shows the heat shield 1 having the catalytic converter situated in its interior during the warm-up phase to the optimal operating temperature of the catalytic converter 2. In this phase, the closure 6, which is located on the top side of the lieat slaield and encloses an opening present there in the form of a through opening in the heat shield, is completely closed.
The heat generated during operation of the internal coinbustion engine tlierefore remains in the interior of the heat shield 1 and heats the catalytic converter rapidly to the desired operating tem-perature.
[0038] In the case shown, the closure 6 completely comprises a flap 13. The flap is expediently manufactured from the saine material as the lieat shield l and is fastened thereto using at least one hinge. Above a specific limiting temperature (or another measured variable representative for the temperature in the environment of the catalytic converter), the flap 13 is opened using an actuating device 7 in the fomi of a positioning motor. To be able to establish reaching the limit-ing temperature, a temperature sensor 8 is fastened to the inside 3 of the heat shield 1. After an analysis described later in connection with Figure 4, the actuating device 7 comes into action if exceeding the fixed limiting temperature is established and opens the flap 13, which is connected to the rod 14, via a push and pull rod 14. This is shown in Figure 1(b).
[0039] With rising temperature in the interior of the heat shield 1 and correspondingly increasing opening by the actuating device 7, the closure 6 exposes an increasingly larger opening cross-section of the through opening 5. The opening of the closure 6 and the exposure of the through opening 5 upon exceeding the predefined limiting temperature ensure that heat accumulated in the interior of the heat shield 1 may escape through the through opening, as illustrated by the ar-rows. Overheating of the catalytic converter 2 in the interior of the heat shield 1 is thus avoided.
If the temperature in the interior of the heat shield 1 sinks again, the actuating device 7 closes the closure back in the direction toward the starting situation shown in Figure 1(a). The through opening 5 is closed by the closure 6 again. In this way, too strong reduction of the temperature in the interior of the heat shield 1 is prevented. Another cold start of the engine would again occur with closed closure 6, so that the catalytic converter 2 in the interior of the heat shield 1 may again be brought rapidly to the required operating temperature. These procedures are repeatable arbitrarily often with good reproducibility, so that optimum operating conditions of the catalytic converter may be ensured with very good noise protection simultaneously.
l5 [00,10] Figures 2(a) through 2(c) show a refinement of the heat shield configuration from Figures 1(a) and 1(b). In addition to the first closure 6, a furthcr closure 6a is provided in the heat shield 1, wliich may close a further tlirough opening 5a in the top area of the heat shield 1. The fur c-tional principle ef both closures corresponds to that of the preceding exemplary embodiment. For simplification, the measuring device 8 is no longer shown.
[00411 Figure 2(a) shows the state of the heat shield 1 in the warm-up phase.
Both closures 6 and 6a are closed, so that the heat remains in the interior of the heat shield 1 and contributes to rap-idly reaching the operating temperature of the catalytic converter 2. Above a first limiting tem-peraturA, whicli may resLlt in overheating of the catalytic converter 2 especially in full load op-eration, the first closure 6 is opened in the way described above and exposes the throiagh opening on the top righ'L side of the heat shield 1, so that the hot air indicated by the arrows inay escape from the interior of the heat shield 1. The second closure 6a is still closed in this phase. It is first opened by the second actuating device 7a upon fiirther temperature increase in the iiiterior of the heat shield I. This is shown in Figure 2(c). To achieve the opening of the closures 6 and 6a at different limiting temperatures, the actuating devices 7, 7a are activated in such a way that they open at different limiting temperatures. Cooler air may enter through this tllxough opening into the interior of the heat shield 1 due to the exposure of the through opening 5a. The colder air flows along the top side of the catalytic converter 2, cools it, and entrains hot air through the through opening 5 on the top right side of the heat shield out of its interior. In this way, effective cooling of the catalytic converter is possible even at very high exhaust gas teinperature. The ex-emplary embodiment described thus allows the catalytic converter to operate under essentially constant temperature conditions even in the event of relatively strongly oscillating exhaust gas temperature.
[0042] Figures 3(a) and 3(b) show an alternative heat shield configuration, in which the heat shield 1 does not completely enclose the catalytic converter 2, but rather is open on its bottom side. The lower edge only has a small distance to the neighboring component 15, which radiates heat in operation of the engine. The measuring device 8 is again not illustrated. As in the exem-plary embodiment from Figures 1(a) through 1(c), the heat shield only has one closure 6. The small distance between heat shield 1 and neighboring component 15 accelerates the achievement of the operating temperature of the catalytic converter 2 witli closed closure 6. Upon reacliing the limiting temperature, the closure 6 is opened by the actuating device 7, as shown in Figure 3(b).
The hot air from the interior of the heat shield may escape through the opening 5. The suction thus arising causes cooler air to flow behind through the space between heat shield 1 and neigli-boring component 15, so that an optimal operating temperature of the catalytic converter 2 is en-sured in spite of the heat radiated by the component 15. The space between heat shield 1 and neighboring coniponent 15 may be tailored - insofar as this is possible in the existing space - to this operating temperature of the catalytic converter'2 and the radiation of the coniponent 15.
[0043] Figure 4 illustrates the sequence upon actuation of the closure 6 using the actuating de-vice 7 in the fonn of a block diagram. A measuring device 8 ascertains measurement data for a measured variable relevant for the function of the object 2 to be shielded continuously or at fixed intervals. This may be the temperature in the environment of the catalytic converter, for example.
The ascertained measured data is transmitted in a way known per se to an analysis unit 9 and analyzed there. The analysis unit compares the measured data to a previously established limiting value, such as a limiting temperature. If the analysis unit 9 establishes that the limiting value has been exceeded, it transmits the result to the control unit 10. In turn, this transmits a control signal to the actuating device 7, because of which it opens the closure 6 to the predefined extent. The closing procedure runs correspondingly, if it is established the temperature falls below the Iimit-ing temperature. Analysis and control units may also be unified in a shared device and installed in the heat shield configuration separately from or jointly with the measuring device 8.
[0044] In the case of a particulate filter, a measuring apparatus 8 may be for the pressure in the interior of the particulate filter. The ascertained measured data is compared to a previously es-tablished base pressure by the analysis unit 9 in this example. If this pressure is exceeded, this is relayed via the control unit 10 to the actuating device 7, on the basis of which it closes the clo-sure 6 in the predefined procedure. This opening procedure runs correspondingly if the pressure falls below the limiting pressure after oxidative regeneration of the particulate filter, for example.
A second limiting pressure may also be established, which is below the first limiting pressure for the closing. The sequence for other measured signals runs comparably.
[0045] Figure 5 shows a partial section of a further enlbodiment of the present invention in the area of the closure 6, which may be opened and closed by an actuating device 7. The mode of operation corresponds to those of the preceding figures. The curves of the heat shield 1 and the closure 6 are adapted to the external contour of the object to be shielded, whose external outline is illustrated by the line 16. By tailoring the curves, the heat shield having closure 6 may be brought very close to the object to be shielded. The solid line at 6 illustrates the open position of the closure, and the dashed line lying underneath illustrates the closed position of the closure.
[0046] Figures 6 and 7 show alternative embodiments of the closure 6. Figure 6 shows an em-bodiment in which the opening 5 in the heat shield 1 is a recess in the external edge area. The opening 5 is closable using a slide 11 as the closure 6. The closure 6 may be displaced in the di-rection of the arrow using the actuating device 7. A situation having almost completely open clo-sure and nearly completely exposed opening 5 is shown.
[0047] Figure 7 shows an embodiment similar to Figure 6, but having a rotating slide 12 as the closure 6. The rotating slide is fastened to the heat shield 1 at a point 17 using screw or rivet connections and is mounted at this point so it is rotatable. By actuating the actuating device 7, namely by extending the rod 14, which is fastened to the rotating slide 12 so it is rotatable at the point 18, more or less, the rotating slide may be pivoted around the point 17, as is illustrated by the double arrow. The through opening 5 in the heat shield is correspondingly covered more or less by the rotating slide 12.
exhaust gas standard Euro 5. In addition to the exhaust gas limiting values in the normal operat-ing phase of an engine, exhaust gas limiting values of the cold starting phase are also incorpo-rated here., The efficiency of the exhaust treatment catalytic converters for the pollutants con-taineci in the exhaust gas is known to differ as a function of the temperature. Thus, for example, the discharge of hydrocarbons and carbon monoxide is particularly high at the beginning of the cold start phase. This is primarily to be attributed to the fact that the catalytic converter has not yet reached its operating temperature. To reduce these pollutants, it is therefore necessary to in-crease the operating temperature of the catalytic converter as rapidly as possible. On the other hand, the operating temperature cannot rise too much, however, because this results on the one hand in the increase of other pollutants sucli as nitrogen oxides in the exhaust gas, and on the other hand, too high a temperature may damage the catalytic converter itself.
[00031 In other cases, it may be desirable, for example, to be able to set a higher or lower tem-perature during a specific operating phase than in other operating phases.
Thus, for example, a particulate filter may pass through an operating phase of higher temperature in wliich accumu-lated particles in the particulate filter are removed by oxidation. Up to this point, reaching this elevated temperature by engine measures or by additional injection of fuels was typical. After completed particle reinoval, the measures were returned to normal operation again. However, this procedure is very complex and requires additional energy.
[0004] In consideration of the problems described above, it is the object of the present invention to specify a heat shield configuration which is capable of setting the operating temperature of an object shielded thereby to a predefined range. The heat shield configuration is on the one hand to allow the temperature to be kept as constant as possible and simultaneously ensure the most rapid possible achievement of the operating temperature. On the other hand, the heat shield con-figuration is also to allow selective operation at various predefined temperatures.
[00051 This object is achieved by the heat shield configuration according to Claim 1. Preferred embodiments are specified in the subclaims.
[0006] The heat shield configuration according to the present invention comprises a heat shield for shielding an object against heat and/or noise having an internal surface facing toward the ob-ject and an external surface facing away from the object. An opening is provided in the heat shield, which goes through the internal and external surfaces. According to the present invention, this opening is at least regionally closable by a closure, which may be opened and closed using an actuating device as a function of a controlled variable relevant for the function of the object.
[00071 The opening iinplemented in the heat shield is exposed by opening the closure, so that better temperature regulation is made possible by the passage thus resulting.
For example, hot air accumulated between the object to be shielded, which is situated neighboring the internal surface of the heat shield, aiid the heat shield may escape througli the exposed opening and tlius the tem-perature in the area around the object to be shielded may be reduced. Vice versa, it is just as pos-sible, for example, to introduce colder air in the direction toward the object to be shielded through the exposed opening and thus reduce the temperature in its environment. It is also possi-ble to feed hot air in the direction toward the object to be shielded through the opened opening or discharge cold air if its temperature increase is desired. In addition, the opening may be at least partially closed in an operating phase of increased temperature, while it is at least partially ex-posed in an operating phase of lower temperature, so that accumulated heat may escape througli the opening. More than two operating phases of different temperatures are also fundamentally settable as a function of the opening size of the opening.
[0008] At least one of the following measured variables comes into consideration as a controlled variable which the closure is opened or closed as a function of:
- a temperature, - a pressure, - a velocity, - an acoustic signal, - an exhaust gas value, - a volume flow, and - an operating time.
[0009] In the preferred application of the present invention in the area of internal combustion engines, very generally, those measured variables which may be measured in the area of the in-ternal combustion engine come into consideration.
[0010] The temperature is expediently a temperature in the environment of the object to be shielded or :he component temperature of the object or another component, if this temperature has effects on the function of the object to be shielded, By measuring the temperature, it may be established directly whether the object to be shielded is threatened with overheating. If so, the actuating device may counteract this by opening the closurc in the heat shield. Vice versa, in the event of too strong cooling, the closure may be closed again using the actuating device.
[00111 The internal pressure of the object to be shielded may particularly be measured as the pressure. A possible application is in particulate filters, in which the internal pressure rises witli increasing charging by particles. The throughput correspondingly worsens, and the particulate filter must be freed of the deposited particles to obtain the desired filtering action. This may be performed by raising the temperature in the interior of the particulate filter so strongly that the particles oxidize and are blown out of the filter. The required temperature increase may be per-formed or at least supported by closiiig the closure, by which heat accumulates in the area of the heat shield around the particulate filter. After passage of a predefined time or altematively upon reaching a lower internal pressure, which allows regular operation of the particulate filter, the closure may be opened again, so that the operation runs at the desired filter operating tempera-ture.
[0012] To be able to operate the object to be shielded at a desired operating temperature - as noted - the temperature of the object itself may be measured directly or in its enviromnent. In-stead of the temperature, however, other measured variables may also be measured, which have effects on the operating temperature of the object. Such a parameter is, for example, a flow which may result in cooling if it flows along the object to be shielded. The closure may thus be closed more in the event of stronger flow and opened more in the event of lesser flow as a func-tion of the flow velocity to set a desired operating temperature. If the object is moved during op-eration, the travel velocity may also be measured instead of a flow velocity.
[0013] Acoustic signals may be ascertained if the object, which produces noise itself, is to be shielded to the environment. In the event of stronger noise development, the closure is expedi-ently closed. The noise pressure is preferably measured.
[0014] Exhaust gas values may also be used as measured variables. For example, concentrations of one or more gases in the exhaust gas may be determined in a way known per se. As noted at the beginning, the effectiveness of the catalytic converter for the various pollutants changes as a function of the temperature. The measurement of the exhaust gas value for these pollutants thus allows conclusions as to whether the temperature is in the desired range. If the irieasured exhaust gas values deviate from predefined setpoint values, the exhaust treatment action may be brought back into the setpoint range by temperature correction.- This is performed according to the pres-ent invention, for example, by opening or closing the closure and correspondingly regulating the opening cross-section of the opening in the heat shield as a function of one or more measured values of the pollutant concentration in the exhaust gas.
[0015] In addition to the cited measured variables, in principle, all those measured variables come into consideration which may have an influence on the function of the object to be shielded or contain information about the operating state or another property of the object. The actuating device may act as a function of only one measured variable or also as a function of multiple measured variables.
[0016] To measure the measured variable, the heat shield configuration according to the present invention expedicntly comprises at least one suitable measuring device. The measuring device may fundamentally be a typical device from the prior art for measuring the particular measured variable. For example, a temperature sensor may be used for temperature measurement, which is attached to the object to be shielded, the heat shield, or another point in proximity to the object.
Analogously, other sensors (pressure, noise pressure, electrochemical value) may be used, which are already known in the prior art. Ideally, sensors which may be replaced independently of other parts are used. In many cases, measuring devices already present in the overall device which comprises the heat shield configuration according to the present invention, such as measuring devices for measuring exhaust gas values or vehicle velocities, may also be used.
[0017] The heat shield configuration expediently also comprises means for analyzing the meas-urement results and control means for controlling the actuating device on the basis of the analy-sis of the measurement result. Both means may be spatially combined in one device and may be situated separately from or integrated in the actuating device. In each case, these are components known per se, which do not have to be described in greater detail here. As already for the meas-uring device, means present in any case in the overall device may also be used for the analysis and control rneans.
[0018] The actuating device may, for example, be a pneumatic, hydraulic, or electrical actuating device. Preferably, a seivomotor is used as an electrical actuating device or a vacuuni unit is used as a pneumatic actuating device. The connection between actuating device and closure is funda-mentally arbitraiy. For example, a push rod or pull rod may be used.
[0019] The opening may either be a through opening in the heat shield or also an opening in an external edge area of the heat shield. Both variants may also be combined with one another in one heat shield. The possibility which is selected is also a function, inter alia, of the available space on the heat shield. The shape of the opening is fundamentally arbitrary and is also primar-ily a function of the available space. The size of the opening is selected as a function of the re-quired heat exchange and/or in regard to the desired noise insulation. The required opening cross-section may be implemented using one or more openings.
[0020] The closure may fundamentally have any arbitrary shape which is capable of closing the opening in the heat shield to the required extent. It may be inserted fitting into the opening or may be situated on the heat shield covering the opening. The way in which the closure exposes the opening is also fundamentally arbitrary. For example, the closure may be displaced laterally in relation to the opening and/or pivoted and/or lifted like a flap off the opening. In the two first cases, the closure is preferably displaced and/or pivoted predominantly parallel to the external surface of the heat shield using a slide. In the latter case, the closure may fundamentally open toward any side of the heat shield. However, for space reasons it is fiequently expedient for the closure to open toward the side of the external surface of the heat shield, because there is fre-quently insufficient space on the side of the internal surface between heat shield and object to be shielded. The flap may also comprise multiple lamellae, which may be opened or closed indi-vidually or jointly. The material of the closure may be selected arbitrarily.
The closure preferably comprises the same material as the heat shield. The closure is fastened to the heat shield de-pending on the type of actuation, for example, using hinges in the case of a flap closure, a screw or rivet connection, which simultaneously provides the rotation point, in the case of a rotating slide, or using guide rails in the case of a slide. A flap closure may possibly also be fastened to an object in proximity to the heat shield and not to the heat shield itself [0021 ] A preferred application of the heat shield according to the present invention is, as already noted, the shielding of components in the area of an internal combustion engine and in particular in the area of the exhaust system. In these applications, the danger primarily exists that the object to be shielded will overheat as a result of the accumulated heat in the area of the heat shield. To prevent this, the heat shield according to the present invention is expediently impleinented in such a way that the closure is opened if a specific limiting temperature is exceeded, so that the accumulated heat may escape from the area between heat shield and object to be shielded. As long as the components situated in the area of the heat shield have not yet reached their operating temperature, however, the accumulation of heat in the area of the heat shield is completely ad-visable, so that the components may reach their optimal operating temperature as rapidly as pos-sible. For this reason, the heat shield according to the present invention is preferably designed in this variant in such a way that the closure remains closed until reaching the limiting temperature.
The teinperature does not have to be measured directly, as noted, but it may be a measured value other than the temperature.
[0022] A further preferred application is the shielding of particulate filters, in particular diesel particulate filters. As described, it may be expedient here to remove the accumulated particles by oxidation at increased temperature in a specific operating phase. Using the heat shield according to the present invention, the required temperature increase may be achieved especially easily and rapidly. In contrast to the prior art, it is frequently no longer necessary to increase the exhaust gas temperature by additional engine measures, although this still remains possible. Rather, the opening in the heat shield may be closed by closing the closure using the actuating device. The temperature then rises in the area of the heat shield and thus also in the particulate filter. If this temperature increase alone is insufficient to begin the oxidative cleaning, in addition, the fuel/air mixture of the engine may be adapted or fuel may be injected directly, as usual. After coanpleted cleaning, the closure is opened again, the additional altered injection is ended if necessary, and the temperature in the area of the heat shield falls again, so that the particulate filter may operate further in the regular operating state.
[0023] gn the case of the heat shield for a particulate filter or a similar device, the closure is ex-pediently opened at lower temperature and closed at increased temperature.
This is preferably reversed for the heat shield described for a catalytic converter. The closure is closed with sinking teniperature here, while it is opened in the event of temperature increase.
Botli variants may be implemented corresponding to the requirements in the scope of the present invention. They may also be used jointly in the same heat shield. Moreover, in a heat shield for a particulate filter, aii additional higher temperature limit may be defined to make the closure open in order to prevent overlaeating of the particulate filter.
[0024] It is not absolutely necessary for the closure to open suddenly if the predefined limiting value is exceeded, for example, and expose the opening 100 %, while the closure is immediately completely closed and completely covers the opening at a value of less than or equal to the lim-iting value. Rather, it is also possible that the opening and closing of the closure occurs within a predefined limiting measured value interval. For example, it may be advisable for the closure to increasingly expose the opening with increasing deviation from the predefined limiting value, so that, for example, with increasing temperature (with more strongly deviating measured value), an increasing temperature exchange with the environment is possible. Vice versa, the opened clo-sure may be increasingly closed again if the increased temperature (or another measured value) falls in the direction toward the limiting value again. In this way, a continuous temperature con-trol adapted to the ambient temperature (or the relevant measured value) is possible, which al-lows the object to be shielded by the heat shield to be kept at an essentially constant operating temperature which is optimal for this object. Closing the opening does not have to result in a hermetic seal of the opening. A significantly reduced temperature exchange in relation to the opened state is generally sufficient. The above statements also apply for the case of opening upon sinking (temperature) measured value and closing upon higher (temperature) measured value.
[0025] The range in which the limiting measured value is set, in which the closure in the heat shield configuration according to the present invention opens or closes, is mainly a function of the temperature at which the object which is to be shielded using the heat shield according to the present invention is to be kept. In the case of catalytic converters, this is expediently the tein-perature at which the best exhaust gas reduction is possible. For particulate filters, on the one hand the optimal temperature for particle filtration and on the other hand the best temperature for oxidative removal of the particles in the particle removal phase may be set.
This particular opti-mal operating teinperature may be achieved very rapidly using the heat shield configuration ac-cording to the present invention, because heat may be accutnulated in the area around the object to be shielded in the warm-up phase by closing the opening using the closure, so that the object heats rapidly. On the other hand, exceeding an optimal operating teinperature too strongly may be prevented by setting the limiting measured value appropriately, upon exceeding which the closure in the heat shield is opened and thus exposes the opening entirely or partially depending on the measured value. Heat accuinulated between heat shield and object to be shielded may es-cape tlirough the exposed opening. Additionally or alternatively, it is possible to inject cool air through the opened opening in the direction toward the object to be shielded (such as the cata-lytic converter, particulate filter, etc.), to cool it.
[0026] Especially good regulation of the temperature in the area between heat shield and object to be shielded is possible if in addition to the first opening having the first closure at least one further opening is provided, which is also closable using a closure to be opened and closed as a function of a measured variable relevant for the function of the object to be shielded. This meas-ured variable may, but does not have to be the same measured variable as for the first closure.
[00271 The further closure may fundamentally be implemented as described above. It may also be opened and closed by an actuating device, as was described above. However, it is also possi-ble to leave out the actuating device and use a closure opening and closing automatically as a function of a measured variable. This is preferably a closure opening and closing as a function of the temperature. The closure therefore expediently has a bimetallic element, which deforms as a function of the teinperature. The bimetallic element may be a part of the closure which deforms in relation to the opening, or a separate part which works together with a slide, rotating slide, or flap and displaces it in relation to the opening.
[00281 The presence of at least one further closure and an opening closable thereby has the ad-vantage that the temperature in the area between heat shield and object to be shielded may be set even more precisely. For example, it is possible to implement the actuating device(s) and clo-sures in such a way that the latter open in sequence if various limiting measured values are ex-ceeded. This may be achieved by storing various limiting measured values and corresponding diftering activation of the closures. The closures may be opened in sequence, for example, in such a way that the exposed total opening cross-section of the openings rises with increasing temperature, so that increasingly more hot air may escape through the exposed operiing. Over-heating may thus be prevented even in the event of very strongly rising temperatures.
[0029] A ftirther advantage which may be achieved by providing multiple openings closable us-ing a closure is that targeted flow guiding is possible in the space between heat shield and object to be shielded. For exainple, cooler air may be introduced in the direction toward the object througli one or more of the exposed openings if the closure is opened, while heated air flows out through the remaining openings. The openings and closures on the heat sliield are expediently oriented in such a way that the hot air flowing out is not directed toward temperature-sensitive par,s situated in the surroundings of the heat shield. Ideally, the hot exhaust air is directed in such a way that it is fed to an external flow existing in the area around the heat shield and is con-veyed thereby. It is also advantageous if the cooler air introduced into the area between heat shield and object to be heated is fed from this external flow existirig in the area around the heat shield.
[0030] As already described above, it is also possible in the case of feeding cooler air into the area between heat shield and object to be shielded that various closures open for the feeding of cooler air at different temperatures. This is also fundamentally true for the closures through which the heated air flows out. In this way, a very constant temperature may be ensured in the area between heat shield and object to be shielded over a large temperature range. Additionally or alternatively to these measures, it is also possible that the closures for the feeding of cooler air open at a different temperature than the closures for the exhaust of heated air. In the latter case, it is preferable for the feed closures to open at a somewhat higher temperature than the closures for the exhaust of hot air.
[00311 The heat shield according to the present invention is not restricted to special shapes or sizes. For example, it may be a planar heat shield, which is attached above the object to be shielded, so that hot air accumulates below the heat shield. The present invention is especially suitable for a heat shield which essentially encloses the object to be shielded on all sides. A com-parable effect may also be achieved if a heat shield opeti on one side is closed by an adjoining component. The object to be shielded is thus largely encapsulated by the heat shield md possibly other components. This typically does not represent a hermetic enclosure, because hermetically terminated passages for supply lines and drain lines are typically not provided in the heat shield.
Nonetheless, the heat exchange with the environment is relatively restricted in these cases, so that overlieating of the components encapsulated in the heat shield may occur very rapidly. On the other hand, the cold start phase is relatively short, because the desired operating temperature is achieved rapidly by the heat retention inside the heat shield. This optimal operating tempera-ture may be kept constant in a desired range easily using the heat shield configuration according to the present invention by the provision according to the present invention of at least one open-ing which is closable by a flap opening and closing as a function of a measured variable. The at least one heat shield, which essentially completely encloses the object to be shielded, addition-ally ensures especiaily good noise insulation.
[0032] The measures suggested according to the present invention may be implemented easily and cost-effectively without additional complicated measures or components in typical heat shields. The main bodies of the heat shield according to the present invention may thus funda-mentally correspond in their implementation to those whicli are already known from the prior art.
Size, shaping, and materials thus correspond to the prior art. Heat shields in sandwicli construc-tion, which comprise two outer layers typically made of inetallic material and an insulating layer embedded between them, are preferred. The surfaces may be smooth, textured, or perforated.
Heat shields of this type are described, for example, in DE 3834054 Al and EP
1775437 Al (European Patent Application 05022095.3) of the applicant. Furthermore, reference may be made to GB 2270555 A and US 2004/0142152 Al.
[0033] The present invention may fundamentally be applied to all heat shields of the prior art.
The present invention is especially suitable for those heat shields which are used in the area of high temperature development and for shielding those objects which may be damaged by excess temperature. A preferred use of the heat shields according to the present invention is therefore in the area of internal combustion engines and particularly in the area of the exhaust system here.
Examples of preferred heat shields are those for catalytic converters, pre-catalytic converters.
diesel particulate filters, or also turbochargers. The present invention may additionally be applied in particular to metallic subfloors or their components in the area of an exhaust system.
[0034] The present invention is explained in greater detail in the following on the basis of drawings. These drawings are exclusively used to illustrate preferred exemplary enlbodiments of the present invention, without the present invention being restricted thereto.
Identical parts are provided with identical reference numerals in the drawings.
[0035] In the figures:
Figure 1(a): schematically shows a cross-section through a first exemplary embodiment of a heat shield configuration according to the present invetYtion for shielding a cata-lytic converter having closed closure;
Figure 1(b): schematically shows the heat shield configuration from Figure 1(a) having opened closure;
Figure 2(a): schematically shows a cross-section tlu-ough a second exemplary embodiment of a heat shield configuration according to the present invention for shielding a cata-lytic converter having two closed closures;
Figure 2(b): schematically shows the heat shield configuration from Figure 2(a) having one open and one closed closure;
Figure 2(c): schematically shows the heat shield configuration from Figure 2(a) having two open closures;
Figure 3(a): schematically shows a cross-section through a third exemplary embodiment of a heat shield cc,iiiguration according to the present invention for shielding a cata-lytic converter having one closed closure, the heat shield being open on one side;
Figure 3(b): schematically shows the heat shield configuration from Figure 3(a) having open closure;
Figure 4: schematically shows a block diagrant to explain the activation of aii actuating de-vice:
Figure 5: schematically shows a partial cross-section tlirough a further exemplary embodi-ment of a heat shield configuration according to the present invention in the area of a closure;
Figure 6: scheinatically shows a top view of a further exemplary enibodiment of a heat shield configuration according to the present invention and a catalytic 'converter thus shielded, and Figure 7: schematically shows a top view of still a furtlier exemplary embodiment of the heat shield configuration according to the present invention and a catalytic con-verter thus shielded.
[0036) Figures 1(a) and 1(b) show a first exemplary embodiment of a heat shield configuration according to the present invention having a heat shield 1, wliich is used for shielding a catalytic converter 2 situated in the interior of the heat shield 1. The catalytic converter 2 may be, for ex-ample, a catalytic converter for treating exhaust gases of an internal combustion engine of a mo-tor vehicle. The exhaust treatment action of the catalytic converter 2 is best within a specific temperature range. This temperature range is to be reached as rapidly as possible, but is not to be exceeded. The catalytic converter 2 is enclosed essentially completely and on all sides by the heat shield 1. In this way, the catalytic converter 2 and its enviromnent are insulated especially well from one another in regard to temperature influences and noise. In addition, the encapsula-tion is used so that the catalytic converter 2 reaches the operating temperature required for opti-mal exhaust treatment rapidly. The cold start phase may thus be shortened by rapid teinperature increase in the interior of the heat shield 1, which is a significant advantage in regard to the ex-pected exhaust gas standard Euro 5.
[00371 Figure 1(a) shows the heat shield 1 having the catalytic converter situated in its interior during the warm-up phase to the optimal operating temperature of the catalytic converter 2. In this phase, the closure 6, which is located on the top side of the lieat slaield and encloses an opening present there in the form of a through opening in the heat shield, is completely closed.
The heat generated during operation of the internal coinbustion engine tlierefore remains in the interior of the heat shield 1 and heats the catalytic converter rapidly to the desired operating tem-perature.
[0038] In the case shown, the closure 6 completely comprises a flap 13. The flap is expediently manufactured from the saine material as the lieat shield l and is fastened thereto using at least one hinge. Above a specific limiting temperature (or another measured variable representative for the temperature in the environment of the catalytic converter), the flap 13 is opened using an actuating device 7 in the fomi of a positioning motor. To be able to establish reaching the limit-ing temperature, a temperature sensor 8 is fastened to the inside 3 of the heat shield 1. After an analysis described later in connection with Figure 4, the actuating device 7 comes into action if exceeding the fixed limiting temperature is established and opens the flap 13, which is connected to the rod 14, via a push and pull rod 14. This is shown in Figure 1(b).
[0039] With rising temperature in the interior of the heat shield 1 and correspondingly increasing opening by the actuating device 7, the closure 6 exposes an increasingly larger opening cross-section of the through opening 5. The opening of the closure 6 and the exposure of the through opening 5 upon exceeding the predefined limiting temperature ensure that heat accumulated in the interior of the heat shield 1 may escape through the through opening, as illustrated by the ar-rows. Overheating of the catalytic converter 2 in the interior of the heat shield 1 is thus avoided.
If the temperature in the interior of the heat shield 1 sinks again, the actuating device 7 closes the closure back in the direction toward the starting situation shown in Figure 1(a). The through opening 5 is closed by the closure 6 again. In this way, too strong reduction of the temperature in the interior of the heat shield 1 is prevented. Another cold start of the engine would again occur with closed closure 6, so that the catalytic converter 2 in the interior of the heat shield 1 may again be brought rapidly to the required operating temperature. These procedures are repeatable arbitrarily often with good reproducibility, so that optimum operating conditions of the catalytic converter may be ensured with very good noise protection simultaneously.
l5 [00,10] Figures 2(a) through 2(c) show a refinement of the heat shield configuration from Figures 1(a) and 1(b). In addition to the first closure 6, a furthcr closure 6a is provided in the heat shield 1, wliich may close a further tlirough opening 5a in the top area of the heat shield 1. The fur c-tional principle ef both closures corresponds to that of the preceding exemplary embodiment. For simplification, the measuring device 8 is no longer shown.
[00411 Figure 2(a) shows the state of the heat shield 1 in the warm-up phase.
Both closures 6 and 6a are closed, so that the heat remains in the interior of the heat shield 1 and contributes to rap-idly reaching the operating temperature of the catalytic converter 2. Above a first limiting tem-peraturA, whicli may resLlt in overheating of the catalytic converter 2 especially in full load op-eration, the first closure 6 is opened in the way described above and exposes the throiagh opening on the top righ'L side of the heat shield 1, so that the hot air indicated by the arrows inay escape from the interior of the heat shield 1. The second closure 6a is still closed in this phase. It is first opened by the second actuating device 7a upon fiirther temperature increase in the iiiterior of the heat shield I. This is shown in Figure 2(c). To achieve the opening of the closures 6 and 6a at different limiting temperatures, the actuating devices 7, 7a are activated in such a way that they open at different limiting temperatures. Cooler air may enter through this tllxough opening into the interior of the heat shield 1 due to the exposure of the through opening 5a. The colder air flows along the top side of the catalytic converter 2, cools it, and entrains hot air through the through opening 5 on the top right side of the heat shield out of its interior. In this way, effective cooling of the catalytic converter is possible even at very high exhaust gas teinperature. The ex-emplary embodiment described thus allows the catalytic converter to operate under essentially constant temperature conditions even in the event of relatively strongly oscillating exhaust gas temperature.
[0042] Figures 3(a) and 3(b) show an alternative heat shield configuration, in which the heat shield 1 does not completely enclose the catalytic converter 2, but rather is open on its bottom side. The lower edge only has a small distance to the neighboring component 15, which radiates heat in operation of the engine. The measuring device 8 is again not illustrated. As in the exem-plary embodiment from Figures 1(a) through 1(c), the heat shield only has one closure 6. The small distance between heat shield 1 and neighboring component 15 accelerates the achievement of the operating temperature of the catalytic converter 2 witli closed closure 6. Upon reacliing the limiting temperature, the closure 6 is opened by the actuating device 7, as shown in Figure 3(b).
The hot air from the interior of the heat shield may escape through the opening 5. The suction thus arising causes cooler air to flow behind through the space between heat shield 1 and neigli-boring component 15, so that an optimal operating temperature of the catalytic converter 2 is en-sured in spite of the heat radiated by the component 15. The space between heat shield 1 and neighboring coniponent 15 may be tailored - insofar as this is possible in the existing space - to this operating temperature of the catalytic converter'2 and the radiation of the coniponent 15.
[0043] Figure 4 illustrates the sequence upon actuation of the closure 6 using the actuating de-vice 7 in the fonn of a block diagram. A measuring device 8 ascertains measurement data for a measured variable relevant for the function of the object 2 to be shielded continuously or at fixed intervals. This may be the temperature in the environment of the catalytic converter, for example.
The ascertained measured data is transmitted in a way known per se to an analysis unit 9 and analyzed there. The analysis unit compares the measured data to a previously established limiting value, such as a limiting temperature. If the analysis unit 9 establishes that the limiting value has been exceeded, it transmits the result to the control unit 10. In turn, this transmits a control signal to the actuating device 7, because of which it opens the closure 6 to the predefined extent. The closing procedure runs correspondingly, if it is established the temperature falls below the Iimit-ing temperature. Analysis and control units may also be unified in a shared device and installed in the heat shield configuration separately from or jointly with the measuring device 8.
[0044] In the case of a particulate filter, a measuring apparatus 8 may be for the pressure in the interior of the particulate filter. The ascertained measured data is compared to a previously es-tablished base pressure by the analysis unit 9 in this example. If this pressure is exceeded, this is relayed via the control unit 10 to the actuating device 7, on the basis of which it closes the clo-sure 6 in the predefined procedure. This opening procedure runs correspondingly if the pressure falls below the limiting pressure after oxidative regeneration of the particulate filter, for example.
A second limiting pressure may also be established, which is below the first limiting pressure for the closing. The sequence for other measured signals runs comparably.
[0045] Figure 5 shows a partial section of a further enlbodiment of the present invention in the area of the closure 6, which may be opened and closed by an actuating device 7. The mode of operation corresponds to those of the preceding figures. The curves of the heat shield 1 and the closure 6 are adapted to the external contour of the object to be shielded, whose external outline is illustrated by the line 16. By tailoring the curves, the heat shield having closure 6 may be brought very close to the object to be shielded. The solid line at 6 illustrates the open position of the closure, and the dashed line lying underneath illustrates the closed position of the closure.
[0046] Figures 6 and 7 show alternative embodiments of the closure 6. Figure 6 shows an em-bodiment in which the opening 5 in the heat shield 1 is a recess in the external edge area. The opening 5 is closable using a slide 11 as the closure 6. The closure 6 may be displaced in the di-rection of the arrow using the actuating device 7. A situation having almost completely open clo-sure and nearly completely exposed opening 5 is shown.
[0047] Figure 7 shows an embodiment similar to Figure 6, but having a rotating slide 12 as the closure 6. The rotating slide is fastened to the heat shield 1 at a point 17 using screw or rivet connections and is mounted at this point so it is rotatable. By actuating the actuating device 7, namely by extending the rod 14, which is fastened to the rotating slide 12 so it is rotatable at the point 18, more or less, the rotating slide may be pivoted around the point 17, as is illustrated by the double arrow. The through opening 5 in the heat shield is correspondingly covered more or less by the rotating slide 12.
Claims (16)
1. A heat shield configuration having a heat shield (1) for shielding an object (2) from heat and/or noise having an internal surface (3) facing toward the object (2) and an external surface (4) facing away from the object (2) as well as an opening (5), which goes through the heat shield (1) having internal surface (3) and external surface (4), characterized in that the heat shield (1) has a closure (6) for at least partially closing the opening (5), and an actuating device (7) is provided, which is implemented to open and close the closure (6) as a function of a controlled variable relevant for the function of the object (2).
2. The heat shield configuration according to Claim 1, characterized in that the controlled variable is selected from at least one of the following measured variables:
- temperature, in particular ambient temperature or component temperature of the object (2), - pressure, in particular internal pressure of the object (2), - velocity, in particular flow or travel velocity, - acoustic signal, in particular noise pressure, - exhaust gas value, volume flow, and - operating time.
- temperature, in particular ambient temperature or component temperature of the object (2), - pressure, in particular internal pressure of the object (2), - velocity, in particular flow or travel velocity, - acoustic signal, in particular noise pressure, - exhaust gas value, volume flow, and - operating time.
3. The heat shield configuration according to Claim 1 or 2, characterized in that it has at least one measuring device (8) for measuring the measured variable.
4. The heat shield configuration according to Claim 3, characterized in that it comprises means (9) for analyzing the measurement results and control means (10) for controlling the actuating device (7) on the basis of the analysis of the measurement result.
5. The heat shield configuration according to one of the preceding claims, characterized in that the actuating device (7) is a pneumatic, hydraulic, or electrical actu-ating device, in particular a servomotor or a vacuum unit.
6. The heat shield configuration according to one of the preceding claims, characterized in that the actuating device (7) is implemented to open the closure (6) if a specific limiting measured variable is exceeded and to close it in the event of a measured variable less than or equal to the limiting measured variable.
7. The heat shield configuration according to Claim 6, characterized in that the actuating device (7) is implemented to increasingly expose the opening (5) with increasing distance from the limiting measured variable.
8. The heat shield configuration according to one of the preceding claims, characterized in that the closure (6) is implemented to open toward the side of the exter-nal surface (4).
9. The heat shield configuration according to one of Claims 1 through 5, characterized in that the actuating device (7) is implemented to close the closure (6) if a specific limiting measured variable is exceeded and to open it in the event of a measured variable less than or equal to the limiting measured variable.
10. The heat shield configuration according to Claim 9, characterized in that the actuating device (7) is implemented to increasingly open or close the opening (5) with increasing distance from the limiting measured variable.
11. The heat shield configuration according to one of the preceding claims, characterized in that the closure (6) is implemented as a slide (11), rotating slide (12), or flap (13).
12. The heat shield configuration according to one of the preceding claims, characterized in that at least one further closure (6a), to be opened and closed as a func-tion of a measured variable relevant for the function of the object (2), is provided for at least partially closing a further opening (5a).
13. The heat shield configuration according to Claim 12, characterized in that at least one further actuating device (7a) is provided, which is im-plemented to open and close the further closure (6a).
14. The heat shield configuration according to Claim 13, characterized in that the actuating device (7a) is implemented to open or close the further closure (6a) at a different limiting measured value than the first actuating device (7) of the first closure (6).
15. The heat shield configuration according to one of the preceding claims, characterized in that the heat shield (1) encloses the object (2) to be shielded essentially on all sides.
16. The heat shield configuration according to one of the preceding claims for shielding an object (2) in the area of an internal combustion engine, in particular a heat shield configu-ration having a heat shield (1) for a catalytic converter, a diesel particulate filter, a turbo-charger, or an exhaust system.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP06020255A EP1905654B1 (en) | 2006-09-27 | 2006-09-27 | Thermal shield |
| EPEP06020255.3 | 2006-09-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2603756A1 true CA2603756A1 (en) | 2008-03-27 |
| CA2603756C CA2603756C (en) | 2015-02-03 |
Family
ID=37441697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2603756A Expired - Fee Related CA2603756C (en) | 2006-09-27 | 2007-09-25 | Heat shield configuration |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US20080083217A1 (en) |
| EP (1) | EP1905654B1 (en) |
| AT (1) | ATE416105T1 (en) |
| BR (1) | BRPI0704110A (en) |
| CA (1) | CA2603756C (en) |
| DE (1) | DE502006002272D1 (en) |
| MX (1) | MX2007011888A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102008003721B4 (en) * | 2008-01-09 | 2014-02-13 | Audi Ag | Heat shield for a motor vehicle |
| JP5278458B2 (en) * | 2011-01-31 | 2013-09-04 | 三菱自動車工業株式会社 | Exhaust gas recirculation device |
| SE1450079A1 (en) * | 2014-01-28 | 2015-07-29 | Scania Cv Ab | Thermal Events |
| FR3023821B1 (en) * | 2014-07-18 | 2016-08-12 | Peugeot Citroen Automobiles Sa | AUTOMOTIVE VEHICLE SUB-FLOOR ARRANGEMENT |
| DE102017202815B4 (en) | 2017-02-22 | 2021-03-18 | Audi Ag | Method and system for regulating a temperature of a component of a vehicle |
| DE102017218374A1 (en) | 2017-10-13 | 2019-04-18 | Continental Automotive Gmbh | Apparatus and method for determining a heating temperature of a heating element for an electrically heatable catalyst and motor vehicle |
| DE102018000955B4 (en) * | 2018-02-06 | 2021-09-30 | Audi Ag | Covering device for a vehicle |
| DE102018202130B4 (en) * | 2018-02-12 | 2021-02-04 | Audi Ag | Component for a motor vehicle and motor vehicle |
| DE102018202131B4 (en) * | 2018-02-12 | 2021-03-18 | Audi Ag | Component for a motor vehicle and motor vehicle |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4409956A (en) * | 1979-07-25 | 1983-10-18 | Barnett Stockton G | Thermostat for stoves |
| SE8002896L (en) * | 1980-04-17 | 1981-10-18 | Bahco Ventilation Ab | VERMEATERVINNINGSANORDNING |
| US4394958A (en) * | 1981-12-23 | 1983-07-26 | Franklin Electric Co., Inc. | Air flow and condition responsive damper |
| DE3834054C3 (en) * | 1988-10-06 | 2000-06-15 | Reinz Dichtungs Gmbh | Heat shield |
| EP0535255B1 (en) * | 1991-08-30 | 1997-11-05 | Wolfgang P. Weinhold | Cooling arrangement for an internal combustion engine in a vehicle |
| GB2270555B (en) * | 1992-09-10 | 1995-10-04 | T & N Technology Ltd | Heat shields |
| DE19722037A1 (en) * | 1997-05-27 | 1998-12-03 | Hecralmat Fa | Heat shield with sound insulation |
| US6951099B2 (en) * | 2001-04-03 | 2005-10-04 | John Dickau | Heated insulated catalytic converter with air cooling |
| US6797402B2 (en) * | 2001-09-28 | 2004-09-28 | Dana Corporation | Insulated heat shield with waved edge |
| DE10253832A1 (en) * | 2002-11-18 | 2004-05-27 | Carcoustics Tech Center Gmbh | Sound absorbing heat shield for motor vehicles to protect chassis from heat, and suppress sound emitted by exhaust silencers is formed entirely of aluminum materials. |
-
2006
- 2006-09-27 AT AT06020255T patent/ATE416105T1/en not_active IP Right Cessation
- 2006-09-27 DE DE502006002272T patent/DE502006002272D1/en active Active
- 2006-09-27 EP EP06020255A patent/EP1905654B1/en not_active Not-in-force
-
2007
- 2007-09-25 CA CA2603756A patent/CA2603756C/en not_active Expired - Fee Related
- 2007-09-26 US US11/904,116 patent/US20080083217A1/en not_active Abandoned
- 2007-09-26 MX MX2007011888A patent/MX2007011888A/en active IP Right Grant
- 2007-09-27 BR BRPI0704110-1A patent/BRPI0704110A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| ATE416105T1 (en) | 2008-12-15 |
| CA2603756C (en) | 2015-02-03 |
| MX2007011888A (en) | 2009-02-11 |
| EP1905654B1 (en) | 2008-12-03 |
| DE502006002272D1 (en) | 2009-01-15 |
| BRPI0704110A (en) | 2008-05-13 |
| US20080083217A1 (en) | 2008-04-10 |
| EP1905654A1 (en) | 2008-04-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20190925 |