WO2017220373A1

WO2017220373A1 - Heating device for a tank, tank device for an exhaust gas aftertreatment system, exhaust gas aftertreatment system

Info

Publication number: WO2017220373A1
Application number: PCT/EP2017/064370
Authority: WO
Inventors: Martin Kiontke
Original assignee: Robert Bosch Gmbh
Priority date: 2016-06-22
Filing date: 2017-06-13
Publication date: 2017-12-28
Also published as: DE102016211175A1

Abstract

The invention relates to a heating device (3) for a tank (2), in particular of an exhaust gas aftertreatment system, comprising a heating body (11), which is at least substantially enclosed by a housing (8) of an electrically insulating material and which can be electrically contacted by a control device. According to the invention, the heating body (11) is designed as a heating resistor and is associated with a heat-conducting element, wherein the heat-conducting element extends through the housing as a closed heat-conducting wall (7).

Description

description

title

Heating device for a tank, tank device for a

Exhaust after-treatment system, exhaust aftertreatment system

The invention relates to a heating device for a tank, in particular an exhaust aftertreatment system, with a radiator, which is at least substantially housed by a housing made of an electrically insulating material and electrically contacted by a drive means.

Furthermore, the invention relates to a tank device for a

Exhaust after-treatment system of a motor vehicle, with a tank for receiving and providing a particular liquid

Exhaust aftertreatment agent and with one in the tank

arranged / arranged heater.

Moreover, the invention relates to an exhaust aftertreatment system.

State of the art

Heating devices, tank facilities and exhaust aftertreatment systems of the type mentioned are known from the prior art. In order to meet the requirements of pollutant emissions in the exhaust gas of internal combustion engines in motor vehicles, it is known to post-treat the exhaust gas by means of appropriate exhaust aftertreatment systems. In addition to the use of one or more catalysts is often a liquid

Exhaust gas aftertreatment agent injected into the exhaust gas, which reacts in an advantageous manner together with the exhaust gas in a downstream catalyst and selectively reduces pollutants in the exhaust gas. Widely used is the so-called S CR process (SCR = selective catalytic reduction), in wherein an aqueous urea solution is injected as exhaust aftertreatment agent in the exhaust gas upstream of an S CR catalyst, so that in the catalyst, the urea reacts with the exhaust gas and reduces nitrogen oxides in the exhaust gas.

Because known liquid exhaust aftertreatment agents can already freeze at temperatures just below 0 ° C, it is also known to provide in a tank providing the exhaust aftertreatment means a heater which heats and thaws frozen exhaust aftertreatment agent as needed. A known solution provides that the heater a

Stamped grid includes, which is encapsulated by a plastic and electrically contacted. By applying the punched grid with an electrical voltage heat is generated, which passes through the encapsulation in the tank and where appropriate heated frozen exhaust aftertreatment agent.

Usually, the stamped grid extends as a body over the entire area to be heated and is flowed through in accordance with current during operation. By providing varying cross-sections in the lead frame, active and passive heating ranges can be adjusted, with larger cross sections having a lower area performance than smaller cross sections, which means a higher electrical resistance to the current.

Disclosure of the invention

The heating device according to the invention with the features of claim 1 has the advantage that a homogeneous heat distribution is achieved by the heater, with passive heating areas are avoided. In addition, the temperature load on the housing is optimized due to the improved or homogenized heat distribution. Furthermore, the heater according to the invention is cheaper to produce and has a high level of ruggedness. According to the invention it is provided that the

Radiator is designed as a heating resistor and is associated with a heat conducting element, wherein the heat conducting element extends through the housing as a closed heat conducting wall. The heat transfer through the housing is thus realized by the heat-conducting element and not by the radiator itself. The radiator is characterized in particular compared to Wärmeleitelement smaller dimensioned. The heat is thus generated locally by the radiator and advantageously distributed by the heat conducting element in the heater. The fact that the heat-conducting element extends as a closed heat-conducting wall through the housing, is a homogenized

Heat distribution safely ensured in the housing. In addition, can be dispensed with a complicated production of the stamped grid. The

Heat-conducting element is preferably made of aluminum or copper and therefore cost feasible. Because the heat conduction wall is also in the

Compared to a stamped grid is relatively stable and robust, eliminates in the production of a pre-encapsulation of the stamped grid to its stabilization.

This also further simplifies manufacturing and reduces costs.

According to a preferred development of the invention, it is provided that the housing is an encapsulation of the heat-conducting element. As a result, the housing is inexpensive and easy to produce. In addition, there is an advantageous heat transfer from the heat conducting element to the housing, since a contact with the contact of the heat conducting element is ensured to the housing over the entire surface.

Furthermore, it is preferably provided that the housing and the one heat-conducting element form a cylinder jacket wall in an annular manner. The heater thus receives a cylindrical shape whose shell wall are formed by the housing and heat conducting element or heat conducting wall. This is in particular the inclusion of a

Liquid removal point in the tank by the heater possible, in particular there a fast and safe thawing frozen

To ensure exhaust aftertreatment agent.

Furthermore, it is preferably provided that the housing has a receiving pocket, in which the heating resistor is inserted. The heating resistor is thus not encapsulated by the housing, as the heat-conducting element, but subsequently plugged into the housing. This is a pre-assembly and, if necessary, a simple replacement of the heating resistor or

Radiator in a simple way possible. Preferably, the receiving pocket on a front side of the cylinder jacket wall on a receiving opening through which the heating resistor in the

Storage bag can be used / inserted. Thus, the heating resistor or the radiator is axially inserted into the housing. This makes it possible that the heating resistor is located in a region of the housing, which is in particular not in contact with the exhaust aftertreatment agent in the tank. As a result, electrical connecting lines leading to the heating resistor can also pass through a region which is not in contact with the exhaust gas aftertreatment agent.

In particular, the receiving opening during assembly in the tank of an opening of the tank is assigned such that through the opening and the

Receiving opening, the electrical lines can be placed, the attached to the tank housing seals the opening and the receiving opening relative to the tank interior, so that the electrically conductive

Elements are safely separated from the exhaust aftertreatment agent.

According to a preferred embodiment of the invention, it is provided that the heating resistor is in touching contact with the heat conducting element. As a result, an advantageous heat transfer from the heating resistor in the

Ensured Wärmeleitelement. For this purpose, the heat-conducting element or the heat-conducting wall expediently extends through the

Receiving opening therethrough or forms an inner wall of the receiving opening, so that the heating resistor when inserted into the

Receiving opening automatically comes in touching contact with the heat-conducting element. Preferably, the receiving opening has a relation to the

Wärmeleitelement obliquely extending surface through which the

Heating resistor when inserted into the receiving pocket against the

Heat conduction is urged. This is when plugging the

Heating resistor in the receiving opening of the contact with the contact

Heat conducting produced in a simple manner and maintained during operation. The heating resistor is clamped or clamped between the housing and the heat-conducting element, so that a permanent contact with the contact is ensured. Furthermore, it is preferably provided that on the housing at least one further functional element, in particular a temperature sensor, a

Level sensor and / or a conveyor is arranged. By means of the temperature sensor, for example, the temperature of the

Exhaust aftertreatment agent and thus the need for thawing

or determine an operation of the heater. By means of the level sensor, the level of the tank can be determined and by means of the conveyor, the exhaust gas aftertreatment agent can be removed from the tank. For this purpose, the conveyor has, in particular, a controllable pump, whose suction connection, in particular within the

Cylinder jacket wall, preferably in the middle, is arranged.

Furthermore, the housing preferably has means for attachment to the tank. The means may be, for example, screw openings, clamping means, screw means or plug means. As a result, a simple attachment of the housing to the tank or on a tank wall, in particular on a tank bottom, possible.

The tank device according to the invention with the features of claim 9 is characterized by the inventive design of the heater. This results in the already mentioned advantages.

The exhaust aftertreatment system according to the invention with the features of claim 10 is characterized by the tank device according to the invention. This also results in the already mentioned advantages.

Further advantages and preferred features and combinations of features emerge in particular from the previously described and from the claims.

In the following, the invention will be discussed with reference to the drawing. Show this

Figure 1 is a sectional view of an advantageous tank means and Figure 2 is a perspective view of a heating device of

Tank means.

FIG. 1 shows, in a simplified sectional illustration, a tank device 1 with a tank 2, in which a heating device 3 is arranged. From the tank

2, only the tank bottom 4 is shown in the sectional view. On the

Tank bottom 4 is the heater 3, which is formed substantially cylindrical. Figure 2 shows the heater 3 in a perspective view. The

Heating device 3 has a cylinder jacket wall 5 which extends annularly or forms a closed ring. A first end face 6 is assigned to the tank bottom 4. The cylinder jacket wall 5 is substantially in the ring at least in the

Substantially continuously closed Wärmeleitwand 7 and the

Wärmeleitwand 7 surrounding housing 8 is formed. The heat-conducting wall 7 forms a heat-conducting element, which is encapsulated by the housing 8. Preferably, the housing is made of HDPE (high density polyethylene). The fact that the heat-conducting wall 7 is encapsulated by the material of the housing 8 is safer

Touch contact between the housing 8 and the heat-conducting wall 7 ensures, so that an advantageous heat transfer can take place.

The housing 8 further has a receiving pocket 9, which has a receiving opening 10 on the end face 6. Through the receiving opening is in the

Receiving pocket 9 axially inserted a radiator 11, which is formed as an electrical heating resistor and electrically contacted by electrical lines 12, 13, which are shown by way of example in Figure 1. The lines 12, 13 lead, for example, to a control device or a control device, which acts on the radiator 11 with an electrical voltage, if necessary, so that heat is generated by the generated current flow and the corresponding resistance of the heating resistor or radiator 11. The tank bottom 4 has the receiving opening 10 associated with a corresponding opening 14 through which the lines 12, 13 can be led to the outside. Through the receiving opening 9, the heat-conducting wall 7 also extends through, so that it forms a side wall of the receiving opening 9. The radiator 11 is disposed directly on the heat-conducting wall 7, so that they are in contact with each other. Optionally, between the radiator 11 and the

Wärmeleitwand 7 a viscous heat conducting 15 interposed, which compensates in particular production-related elevations or depressions in the material of the heat conducting wall 7 and / or the radiator 11. Preferably, the receiving pocket 9 is formed such that the radiator 11 is clamped between the housing and the heat-conducting wall 7 in order to ensure a secure contact contact. Optionally, the the

Wärmeleitwand 7 opposite side wall of the receiving pocket 9 be aligned obliquely, as indicated by a dashed line 16, so that when inserting the radiator 11 into the receiving pocket 9 of this against the

Wärmeleitwand 7 is pressed.

The housing 8 is expediently screwed to the tank bottom 4, glued and / or welded, so that the receiving pocket 9 is only open or accessible to the outside of the tank 2. This is

ensures that the electrical components of the heater 3 are safely protected from located in the tank 2 exhaust aftertreatment agent.

Because the heat-conducting wall 7 extends closed through the housing 8 and is in contact with the radiator 11, the heat generated by the radiator 11

Transfer heat in its control advantageous in the heat-conducting wall 7, which distributes the heat in the tank interior evenly or homogeneously. This will also cause a local temperature load on the

Reduced housing 8 and thus increases the durability of the heater 3. Due to the advantageous full-scale heat distribution, the performance becomes

Warming up the frozen exhaust aftertreatment means reduced especially at low levels or inclinations and increases the overall performance of the heater 3 over all levels. The heater 3 makes optimum use of the available installation space in the tank 2 and, with optimized heat distribution over the entire circumference, ensures a reduction in current carrying Areas, for example, which offers advantages in terms of selection reliability or durability of the heater 3. The fact that the heat-conducting wall 7 is used in particular instead of a conventional stamped grid, costs and production costs are reduced. In particular, eliminates a pre-injection, which would be necessary to stabilize the stamped grid.

The fact that current-carrying parts are only in the receiving pocket 9 and are led out from this through the receiving opening 10 and the opening 14, it is avoided that electrochemical interactions between different materials in the tank can take place. In particular, the housing 8 is made of the same material as the tank 2, which also facilitates welding of the heating device 3 with the tank 2.

Claims

claims

Heating device (3) for a tank (2), in particular one

Aftertreatment system, comprising a radiator (11) of a housing (8) made of an electrically insulating material at least in

Essentially housed and electrically contacted by a drive device, characterized in that the heating body (11) is formed as a heating resistor and associated with a heat conducting element, wherein the heat conducting element extends through the housing as a closed heat conducting wall (7).

Heating device according to claim 1, characterized in that the housing (8) is an encapsulation of the heat-conducting element.

Heating device according to one of the preceding claims, characterized in that the housing (8) and the heat-conducting element form a cylinder jacket wall (5) in an annular manner.

Heating device according to one of the preceding claims, characterized in that the housing (8) has a receiving pocket (9), in which the heating resistor is inserted.

Heating device according to one of the preceding claims, characterized in that the receiving pocket (9) on a front side (6) of the cylinder wall (5) has a receiving opening (10) through which the heating resistor in the receiving pocket (9) used / inserted.

Heating device according to one of the preceding claims, characterized in that the heating resistor is in touching contact with the heat conducting element.

7. Heating device according to one of the preceding claims, characterized

characterized in that on the housing (8) at least one further Functional element, in particular a temperature sensor, a level sensor and / or a conveyor is arranged.

8. Heating device according to one of the preceding claims, characterized

characterized in that the housing (8) has means for attachment to the tank (2).

9. Tank device (1) for an exhaust aftertreatment system of

Motor vehicle, with a tank (2) for receiving and providing a particular liquid exhaust aftertreatment agent, and with a in the tank (2) arranged / arrangeable heater (3), characterized by the formation of the heating device (3) according to one or more of claims 1 till 8.

10. exhaust aftertreatment system with a tank device (1) according to claim 9.