EP0707434A2 - Radiator for motor vehicle heating system - Google Patents

Abstract

The heating body has a vane/tube block through which air to be heated is passed and which has at least one row of tubes (6) arranged between the vanes (7) so as to conduct heat. At least some of the tubes are in the form of PTC heating tubes (8) with envelope tubes with integrated PTC heating elements. The heating power of the PTC heating elements and the dimensions of the vanes enclosing the associated envelope tubes are matched to the heat absorbing capacity of the air flowing through the vanes. Each second tube in the block can be replaced by an envelope tube with a PTC tube with PTC heating elements.

Description

The invention relates to a radiator for a heating system of a motor vehicle with a fin / pipe block through which the air to be heated can flow, and which has at least one row of pipes arranged in a heat-conducting manner between the fins.

Such a radiator is generally known for motor vehicles. The radiator has a fin / tube block assembled from round or flat tubes and corrugated fins or corrugated fins, to each of which a water box is connected on both ends. Coolant liquid, which is heated by the cooling of the motor vehicle engine, is passed through the pipes of the radiator. The corrugated fins or corrugated fins enclosing the tubes are traversed by air across the tubes, the air being warmed up due to the heat-conducting properties of the corrugated fins or corrugated fins. In newer, consumption-minimized motor vehicles with a combustion engine or in electric vehicles, however, the engine heat generated is not sufficient to sufficiently heat the air flowing through the fin / tube block to heat the passenger compartment. In addition, in motor vehicles with an internal combustion engine only after the warm-up of the Motor achieves an effective heating power, because only then is the coolant liquid warmed up accordingly.

From FR 26 60 746 A1 it is already known to provide a radiator for a motor vehicle provided with a fin / tube block with an additional electrical heater in the form of a U-shaped heating element. Installation and connection of this heating element are, however, relatively complex, since the heating element must be inserted between two rows of plate packs while making structural changes. In addition, the U-shaped heating element is only arranged in the middle of the finned tube block, so that the additional heating effect is comparatively small.

The object of the invention is to provide a radiator of the type mentioned, which can be electrically heated with simple structural measures and without requiring additional installation space.

This object is achieved in that at least some of the tubes are in the form of PTC heating tubes which have cladding tubes provided with integrated PTC heating elements. This measure means that no additional installation space is required for the arrangement of PTC heating elements, since the installation space available for the tubes in the fin / tube block is used in a simple manner for the integration of the PTC heating elements. The arrangement of the PTC heating elements in the cladding tubes results in a compact structure with defined dimensions that do not go beyond the dimensions of the tubes of the finned tube block. The outer dimensions of the fin / pipe block and thus the radiator do not change. Due to the thermally conductive connection of the cladding tubes with the fins, ie the corrugated fins or corrugated fins of the radiator, the air flowing through the radiator is heated even if the tubes of the fin / tube block either do not have liquid or cold liquid flowing through them will. The cladding tubes with the PTC heating elements are arranged in the radiator either in connection with tubes through which coolant flows, so that the PTC heating elements represent additional heating for the radiator. Alternatively, however, it is also provided that all tubes of the finned tube block of the radiator be replaced by cladding tubes provided with PTC heating elements, so that an exclusively electric radiator results, the dimensions of which correspond to the known coolant radiators.

In an embodiment of the invention, the heating power of the PTC heating elements and the dimensioning of the fins surrounding the assigned cladding tubes are matched to the heat absorption capacity of the air flowing through the fins. This coordination is intended to prevent the PTC heating elements from heating up adjacent pipes through which coolant flows. The PTC heating elements are only intended to heat the air.

In a further embodiment of the invention, every second tube in the fin / tube block is replaced by a PTC heating tube having a cladding tube with PTC heating elements. This results in an even distribution of both types of heating, so that either only the PTC heating elements or only the coolant tubes or both heating options can be in operation in combination.

In a further embodiment of the invention, the cladding tubes are integrated components of the fin / tube block. The cladding tubes are therefore integrated together with the corresponding fins and tubes of the fin / tube block in one operation, so that there is no additional structural effort for the integration of the cladding tubes into the radiator.

The cladding tubes are advantageously soldered together with the fin / tube block, or the cladding tubes are including the PTC elements integrated into the fin / tube block by mechanical joining.

In a further embodiment of the invention, the PTC elements for a cladding tube are combined in a frame adapted to the cladding tube, which can be inserted into the cladding tube. As a result, the PTC elements are preassembled into a slide-in component in the form of the frame and, in this compact design, can be easily inserted into the corresponding cladding tube from an open end.

In a further embodiment of the invention, the PTC elements are arranged watertight in the cladding tube. This prevents corrosion that could impair the functionality of the PTC elements.

In a further embodiment of the invention, an insertion side of the frame is wedge-shaped. This measure makes it easier to insert the PTC elements into the assigned cladding tube.

In a further embodiment of the invention, all PTC heating tubes are connected to a common circuit. As a result, all PTC heating elements are switched on and off together. The result is homogeneous electrical heating.

Fig. 1

zeigt eine Ausführungsform eines erfindungsgemäßen Heizkörpers für eine Heizung eines Kraftfahrzeugs, der einen mit Wellrippen und Flachrohren versehenen Rippen-/Rohrblock aufweist, wobei jedes zweite Flachrohr durch PTC-Heizelemente ersetzt ist,

Fig. 2

einen Schnitt durch den Heizkörper nach Fig. 1 in schematischer Darstellung entlang der Schnittlinie II-II in Fig. 1,

Fig. 3

eine weitere Ausführungsform eines erfindungsgemäßen Heizkörpers, bei dem der Rippen-/Rohrblock ein Welllamellenpaket aufweist,

Fig. 4

einen Schnitt durch den Heizkörper nach Fig. 3 entsprechend der Schnittebene II-II nach Fig. 1,

Fig. 5

eine weitere Ausführungform eines erfindungsgemäßen Heizkörpers, bei dem der Rippen-/Rohrblock zwei hintereinander angeordnete Rohrreihen aufweist,

Fig. 6

einen Schnitt durch den Heizkörper nach Fig. 5, in den die beiden hintereinander angeordneten Rohrreihen erkennbar sind, wobei in einer vorderen Rohrreihe fünf Rohre durch mit PTC-Heizelementen versehene Hüllrohre ersetzt sind,

Fig. 7

einen weiteren Heizkörper gemäß der Erfindung, bei dem die Heizleistung zur Erwärmung der die Wellamellen durchströmenden Luft ausschließlich von den PTC-Heizelementen erzielt wird,

Fig. 8

einen Schnitt durch den Heizkörper nach Fig. 7,

Fig. 9

in einem vergrößerten Längsschnitt ein mit PTC-Heizelementen versehenes Hüllrohr, und

Fig. 10

einen Querschnitt durch das Hüllrohr nach Fig. 9 entlang der Schnittlinie X-X in Fig. 9.

Further advantages and features of the invention emerge from the subclaims and from the following description of preferred exemplary embodiments of the invention, which are illustrated with the aid of the drawings.

Fig. 1

1 shows an embodiment of a heater according to the invention for heating a motor vehicle, which has a fin / tube block provided with corrugated fins and flat tubes, with every second flat tube being replaced by PTC heating elements,

Fig. 2

2 shows a section through the heating element according to FIG. 1 in a schematic illustration along the section line II-II in FIG. 1,

Fig. 3

a further embodiment of a radiator according to the invention, in which the fin / tube block has a corrugated fin package,

Fig. 4

3 shows a section through the heating element according to FIG. 3 corresponding to the section plane II-II according to FIG. 1,

Fig. 5

another embodiment of a radiator according to the invention, in which the fin / tube block has two rows of tubes arranged one behind the other,

Fig. 6

5, in which the two rows of tubes arranged one behind the other can be seen, five tubes in a front row of tubes being replaced by cladding tubes provided with PTC heating elements,

Fig. 7

a further radiator according to the invention, in which the heating power for heating the air flowing through the corrugated fins is achieved exclusively by the PTC heating elements,

Fig. 8

7 shows a section through the heating element according to FIG. 7,

Fig. 9

in an enlarged longitudinal section, a cladding tube provided with PTC heating elements, and

Fig. 10

9 shows a cross section through the cladding tube according to FIG. 9 along the section line XX in FIG. 9.

A radiator according to FIGS. 1 and 2 has a fin / tube block arranged between an upper water tank (1) and a lower water tank (2). The fin / tube block is provided with several flat tubes (6) running between the two water tanks (1, 2), between which heat-conducting corrugated fins (7) are arranged as fins. The upper water tank (1) is divided into an inflow and an outflow area by a partition (3). The inflow area of the water tank (1) is provided with an inflow connection (4) and the outflow area with an outflow connection (5). The radiator is connected by means of its two connections (4 and 5) in a manner known per se to a coolant circuit for an internal combustion engine of the motor vehicle. Through the flat tubes (6) assigned to the inflow area of the upper water tank (1), the cooling liquid already heated by the cooling of the motor flows into the lower water tank (2) and from there through the flat tubes (6 ) through to the drain connection (5). The radiator can be used in both passenger cars and commercial vehicles.

1, every second flat tube (6) connecting the two water boxes (1 and 2) to one another is replaced by a respective PTC heating tube (8), each of which represents a cladding tube provided with PTC elements. 1, a total of five PTC heating tubes (8) are arranged, which are each inserted between two adjacent flat tubes (6). Each PTC heating tube (8) is thermally conductive in connection with the respectively adjacent corrugated fins (7), the heating power of the PTC heating elements arranged in the PTC heating tube (8) being dimensioned such that only heating of the adjacent corrugated fins (7) , but not the flat tubes (6) connected to them. The dimensions of the PTC heating tubes (8) essentially correspond to those of the flat tubes (6). As will be described in more detail below, each PTC heating tube (8) has a cladding tube which, in the exemplary embodiment, consists of aluminum.

The corresponding PTC heating elements are inserted into each cladding tube by means of a frame, which is also described in more detail below. These cladding tubes are integrated in the fin / tube block and are integrated - initially still hollow - during the manufacture of the fin / tube block. The PTC heating elements are then inserted using the compact frame that is adapted to the internal dimensions of the cladding tubes. In the exemplary embodiment according to FIG. 1, each cladding tube is part of the fin / tube block and is soldered together with the flat tubes (6) and the corrugated fins (7). The PTC heating elements are then inserted into the corresponding cladding tubes and electrically connected to one another. A ground tap (10) for forming the electrical circuit is provided on the upper water tank (1). All positive poles of the PTC heating elements are connected to a common positive conductor (9) leading out to the side of the fin / tube block.

The radiator according to FIGS. 3 and 4 corresponds in terms of its functional structure to the radiator according to FIGS. 1 and 2. Instead of corrugated fins, corrugated fins (7a) are provided in this radiator as fins, which together with the flat tubes (6a) and PTC heating tubes (8a) are mechanically joined together to form a fin / tube block. In this exemplary embodiment, too, the PTC heating elements for a cladding tube according to FIGS. 9 and 10 are combined in a frame, by means of which a compact PTC insertion part is formed for each cladding tube. To manufacture the radiator, the rib / pipe block is first cassetted. When inserted into the cladding tubes, the PTC insert parts are clamped from above with the corrugated fins (7a). The subsequent expansion of the flat tubes (6a) additionally clamps the PTC insert parts in the associated cladding tubes, so that the PTC heating tubes (8a) are adequately secured in the fin / tube block.

In an embodiment of the invention, not shown, similar to FIGS. 3 and 4, the PTC insert parts are first inserted into the corresponding cladding tubes and then the cladding tubes together with the PTC insert parts are inserted between the corrugated fins (7a) and braced with them. In an advantageous embodiment, the cladding tubes or the PTC insertion parts are designed in a wedge shape on their insertion side in order to facilitate insertion.

The radiator according to FIGS. 5 and 6 corresponds essentially to the radiator according to FIG. 3, but the radiator has two rows of pipes arranged one behind the other. These rows of tubes are held by means of a corrugated fin package (7b). The rear row of tubes in FIG. 6 represents a row of liquid-carrying tubes and consists of eleven flat tubes (6b). In the front row of tubes, every second flat tube (6b) is replaced by a PTC heating tube (8b). The electrical connections of the PTC heating pipes (8b) with the negative pole (10b) on the upper water tank (1b) and a corresponding positive pole (9b) led outwards correspond to the previously described exemplary embodiments. The radiator is either soldered or mechanically joined. The PTC heating tubes (8b) in the front tube row of the fin / tube block serve as additional electrical heating in accordance with the previously described exemplary embodiments.

The radiator according to FIGS. 7 and 8 can only be heated electrically. This heater is not connected to a coolant circuit of an internal combustion engine of the motor vehicle, but is intended to replace a corresponding liquid heater. As can be seen from Fig. 8, this radiator corresponds to the dimensions of a liquid radiator. However, the water boxes are omitted. Alternatively, this radiator can be connected to a heater that is already present in a motor vehicle or is designed for such a motor vehicle, if the motor vehicle has an electric motor. Such a radiator can also be used in low-heat engines, such as optimized diesel engines. The flat tubes (13) of this radiator have no liquid-carrying function, but only contribute to the stability of the finned tube block. The flat tubes (13) are held on their upper end by an upper support (11) and on their lower end by a lower support (14). The radiator has a corrugated fin package (12) corresponding to the known radiators. According to the previously described embodiments, several PTC heating tubes (15) are inserted between two flat tubes (13) into the plate pack (12) and held mechanically or by soldering in this plate pack.

Since in all of the described embodiments the cladding tubes are not drawn as far as the water boxes or to the carriers (FIG. 7) and are fixed in these, the cladding tubes are flanged on the opposite sides of the corrugated lamella packs. A form-fitting fixation of the cladding tubes relative to the corrugated fin packs is thus achieved.

Each PTC heating tube (15) has a flat, thin-walled aluminum cladding tube (20), the cross section of which corresponds to the cross section of the flat tubes (13). An insertion frame (22) made of plastic is inserted into this cladding tube (20), on which five PTC heating elements (19) are held. All PTC heating elements (19) rest on a plus conductor (18) made of aluminum, which is spaced apart from the inner wall of the cladding tube (20) by means of insulation. The insulation (23) is provided in the form of a plastic film. Spacers (21) made of plastic or of another non-conductive material are provided between adjacent PTC components (19). The PTC insert part is formed by the insert frame (22) in connection with the PTC components (19), the positive conductor (18) and the insulation (23), which are prefabricated in a watertight manner. This PTC insert part is inserted into the cladding tube (20). In a further exemplary embodiment of the invention, the cladding tube (20) is also part of the PTC insert part and is prefabricated together with the other parts. The prefabricated insert part is pushed into a corresponding cladding tube already integrated into the finned tube block when the radiator is assembled. The PTC insert parts are fixed in the cladding tubes already integrated in the finned tube block by gluing, clamping or spot welding.

Claims (10)

Radiator for a heating system of a motor vehicle with a fin / tube block through which air to be heated can flow and which has at least one row of tubes arranged in a heat-conducting manner between the fins, characterized in that at least some of the tubes (6, 6a, 6b, 13 ) is designed in the form of PTC heating tubes (8, 8a, 8b, 15) which have cladding tubes (20) provided with integrated PTC heating elements (19). Radiator according to claim 1, characterized in that the heating power of the PTC heating elements (19) and the dimensioning of the fins (7, 7a, 7b, 12) surrounding the assigned cladding tubes is based on the heat absorption capacity of the fins (7, 7a, 7b, 12 ) air flowing through them are matched. Radiator according to Claim 2, characterized in that on the fin / tube block every second tube is replaced by a PTC heating tube (8, 8a, 8b) having a cladding tube (20) with PTC heating elements (19). Radiator according to claim 3, characterized in that the cladding tubes (20) are integrated components of the fin / tube block. Radiator according to claim 4, characterized in that the cladding tubes (20) are soldered together with the fin / tube block. Radiator according to claim 4, characterized in that the cladding tubes, including the PTC heating elements, are integrated into the fin / tube block by mechanical joining. Radiator according to Claim 4, characterized in that the PTC elements (19) for a cladding tube (20) are combined in a frame (22) which is adapted to the cladding tube (20) and can be inserted into the cladding tube (20). Radiator according to claim 7, characterized in that the PTC heating elements (19) are arranged watertight in the cladding tube (20). Radiator according to claim 8, characterized in that an insertion side of the frame is wedge-shaped. Radiator according to one of the preceding claims, characterized in that all PTC heating pipes (8, 8a, 8b, 15) are connected to a common circuit.

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