DE102004051746A1 - Tank module for a reducing agent and dosing system - Google Patents

Abstract

The invention relates to a tank module for a reducing agent for the after-treatment of exhaust gases from an internal combustion engine, comprising at least one tank module housing (10). DOLLAR A It is proposed that within a tank chamber (11) of the tank module housing (10) a metering system (12) for metering a reducing agent is arranged in an exhaust system. DOLLAR A The invention further relates to a metering system for supplying a reducing agent from a tank chamber (11) in an exhaust system, wherein the metering system (11) is designed as a built-in module (13).

Description

The Invention is based on a tank module for a reducing agent as well a dosing system according to the preambles of the independent claims.

to Reduction of the contained in an exhaust gas of an internal combustion engine Nitrogen oxides has become for such internal combustion engines operated with excess air, a method for selective catalytic reduction as advantageous proved. In this process, the nitrogen oxides are combined with Ammonia in a selective catalyst to nitrogen and water implemented. The necessary for the catalytic conversion of nitrogen oxides Reducing agent is instead of the ammonia in the form of an aqueous urea solution carried in the vehicle, from the ammonia by hydrolysis of the urea solution in each required for implementation Amount can be released. It is known, the urea solution by means of a arranged in a metering mixing chamber, for example by Prepare aerosol formation and inject it into an exhaust system. An introduction of the urea solution without air supply is also possible. The dosing system is usually in a die-cast housing arranged. The disadvantage here is the relatively large size and the complex, internal and external connecting pipes and connecting hoses. These are installation-intensive and prone to repair. Dependent on The concentration of urea is also mainly in the external Connecting pipes and connecting hoses the risk of freezing the aqueous Urea solution. At certain temperatures even the internal connection lines endangered by freezing.

Advantages of inventions

It is proposed in the tank module according to the invention for a reducing agent for the aftertreatment of exhaust gases from an internal combustion engine, comprising at least one tank module housing, within a tank chamber of the tank module housing a metering system for metering to arrange a reducing agent in an exhaust system of a vehicle. The dosing system is preferably designed as a compact installation module. The installation of the dosing system in the tank module is characterized by the inventive arrangement especially easy. It is advantageous that the metering system Space-saving in the tank module can be accommodated, so that the Size can be reduced can. As a compact built-in module, the dosing system conveniently comprises all necessary components, e.g. Electronics, pumps and / or dosing agents, which are arranged within the built-in module so that no separate Hose lines are necessary. This allows the assembly of the dosing system in the tank module particularly easy to be performed, and the connection The connecting pipes and connecting hoses can be very quick and easy carried out become. It is advantageous that the repair vulnerability the connecting pipes and connecting hoses by their internal installation can be reduced to a minimum. The tank module can be a structural Form unit with a fuel tank in which fuel to operate the vehicle is carried, or alternatively be a separate tank module independent of the fuel tank.

By The compact design within the tank module is the dosing system advantageously less sensitive to mechanical environmental influences. For example can the shaking load are damped by the reducing agent located in the tank chamber.

Especially advantageous is the use of the tank module according to the invention in commercial vehicles, thereby a slight pre-assembly of the tank module is made possible. conveniently, can the mounting solution independently be carried out by the equipment level of the commercial vehicle, because no special mounting bracket needed become. The tank module housing may preferably comprise a fuel tank, so that with the inventive tank module a compact built-in module can be realized. In a preferred embodiment the tank module according to the invention the metering system is arranged by means of a within the tank chamber Heating device can be heated. Preferably, the tank heater to a casing the dosing be arranged so that this at the same time can be heated with the reducing agent refueled tank chamber. It is unnecessary Thus, a separate heater for the tank and the metering system. Further a heating of the internal connecting lines can be omitted since the entire dosing system can be heated by the tank heater. Likewise, a separate heating a suction line omitted, because The dosing system includes a pump that sucks directly from the tank. Particularly advantageous in the over a water circulation of an engine cooling system operated tank heating the tank module according to the invention is that a connected load on the electrical system significantly reduced can be because no electrical heating cable is required.

The dosing system can be cooled by means of a cooling system arranged inside the tank chamber. Preferably, those of an exter NEN-fed cooling water lines are guided around the housing of the metering system and are discharged via an external return for the cooling water. The cooling water lines are conveniently located within the tank module and thus have a particularly efficient efficiency.

The Dosing system can have a lid with which the complete Installation module to the tank module housing is flanged. Preferably, on the cover circumferential bores arranged for receiving fastening elements, with which the Flush mounted module to the tank module housing can be.

One Dosing system according to the invention for feeding a reducing agent from a tank chamber into an exhaust system is designed as a built-in module. Preferably, the metering system e.g. in a cylindrical housing be arranged, wherein in the installation module at least partially a circuit board formed control components, for example a control unit, sensors and the like., Are arranged. In the installation module may suitably also a tank level sensor and preferably a Quali tätssensor for the Reducing agent may be arranged. The dosing system can be used both for air-assisted dosing be formed of the reducing agent as well as for dosing the Reducing agent without air support.

Preferably the installation module has a pump. The pump can be the reducing agent suck directly from the tank chamber or via a between an inlet from the tank chamber and the pump arranged filter chamber. At the inlet can be a check valve be arranged. The filter chamber can face away from the pump on its Side include a closure device, with the filter chamber lockable is. In the filter chamber, a filter insert is preferably arranged, the possible Contaminants, particles and the like. Filtered from the reducing agent. A change of the filter insert is preferably after a removal the complete unit possible.

In a cheap one Embodiment are a mixing chamber and air supply elements in the Integrated module.

The Reducing agent can by means of a suction pipe from the filter chamber on the Pump with mounted pressure and temperature sensor in the mixing chamber be transported. In a system with air support can over a On a cover arranged compressed air connection air into the mixing chamber with an air control valve with attached air pressure and air temperature sensor controls the air supply. By means of a pressure line the reductant-air mixture is transported into the exhaust system. It is also a direct injection of the reducing agent possible.

The Metering system can be closed by means of a lid, preferably be screwed. The lid is preferably oval and includes circumferential Holes for receiving fasteners with which the Installation module on the tank module housing can be flanged. The lid can be a connection piece for a return line having the reducing agent in the tank chamber. The case of the Dosing system is - to on the cover flange - preferably from a reducing agent resistant Made of plastic, as formed by the tank installation in the stainless steel Tank module sufficient protection against electromagnetic radiation given is.

drawing

Further Embodiments, Aspects and advantages of the invention are also independent of their summary in claims, without restriction the general public from below with reference to a drawing embodiments the invention.

in the Following shows

1 schematically an embodiment of a tank module according to the invention;

2 the tank module after 1 with a cooling system;

3 the tank module after 1 with a tank return pipe provided in a lid;

4 schematically an illustration of a metering system according to the invention; and

5 a preferred Dosiersystemanordnung in an exhaust system of a motor vehicle.

description the embodiments

Same Elements in the figures are each given the same reference numbers designated.

1 shows a preferred tank module for a reducing agent for post-treatment of exhaust gases from an internal combustion engine. The tank module comprises a tank module housing 10 with a tank chamber 11 and a fuel tank 14 , On the tank room 11 is a filler neck 27 arranged, with the reducing agent in the tank chamber 11 can be fueled. Inside the tank chamber 11 of the tank module housing 10 is a dosing system 12 arranged for metering a reducing agent in an exhaust system. Overall, the dosing system 12 as a compact built-in module 13 designed completely from the tank compartment 11 is coated for the reducing agent. The dosing system 12 is arranged in a cylindrical housing and with a lid 17 closable. The lid 17 has circumferential holes 28 on, with the complete built-in module 13 to the tank module housing 10 is flanged. The dosing system 12 is by means of a within the tank chamber 11 heated to parent heater, which in the 1 is not apparent.

For safety reasons, one is between the fuel tank 14 and the tank chamber provided for the reducing agent 11 arranged partition 26 double-walled design. The fuel tank 14 has a filler neck 25 for fuel.

2 schematically shows the tank module after 1 with a cooling system 16 that is inside the tank chamber 11 is arranged. The cooling system 16 includes an inlet 29 for cooling water, a spiral around the built-in module 13 of the dosing system 12 arranged cooling water pipe 30 and a return 31 for the cooling water. The cooling water pipe 30 is conveniently located within the tank module and thus has a particularly efficient efficiency, because the cooling can not be discharged to the outside and thus no losses occur.

In the 3 is a metering system according to the invention 12 shown as a built-in module 13 is designed. The installation module 13 is cylindrical and has an oval lid 17 with an edge protruding on one side. On the lid are holes 28 arranged for receiving fastening elements, not shown, with which the dosing system 12 to that in the 3 not shown tank module housing 10 is flanged. On the protruding edge of the lid 17 is a tank return 32 arranged over which the reducing agent in the tank chamber 11 can be returned. On the lid 17 is also a compressed air connection 33 arranged over the air for aerosol formation in a mixing chamber of the dosing system, not shown 12 is introduced. Further, on the lid 17 a pressure line connection 34 provided over which the processed in the mixing chamber reducing agent is injected into an exhaust system, not shown, for emission control. On a circuit board 21 are control components 22 , For example, sensors arranged.

4 schematically shows an illustration of a metering system according to the invention 12 in which at least the components pump 18 , Mixing chamber 19 and air supply elements 20 in the installation module 13 are summarized. The reducing agent is via a direct feed 35 from the tank chamber, not shown 11 into the dosing system 12 brought in. Right at the inlet 35 is a check valve 23 arranged, for example, in the event of a sudden pressure change in the direction of the tank chamber 11 is closable. The reducing agent is first in a normal operation conveying direction in a filter chamber 24 brought in. This is at its free end by a closure lid 38 closable. Through a filter insert 37 The reducing agent is roughly cleaned and freed, for example, of particles and impurities. Subsequently, the reducing agent via a suction pipe 39 and a pump 18 into the mixing chamber 19 brought in. The pump 18 and the mixing chamber 19 are in one of the filter chamber 24 separate second chamber 40 of the dosing system 12 arranged. About a pressure sensor 41 and a temperature sensor 42 be pressure and temperature of the mixing chamber 19 controlled reducing agent controlled. The pressure sensor 41 and the temperature sensor 42 are together with other control components 22 on a circuit board 21 educated.

Via a compressed air connection 33 is used to aerosol compressed air into the mixing chamber 19 of the dosing system 12 introduced, with an air control valve 20 and an air pressure sensor 36 take control. Via a pressure line connection 34 will that be in the mixing chamber 19 prepared reducing agent injected via a nozzle, not shown in an exhaust system for exhaust gas purification. The compressed air connection 33 and the pressure line connection 34 are on a cover 17 arranged with which the dosing system 12 on one of the cap 38 opposite side is closed. The lid 17 has a larger diameter than the cylindrical housing of the dosing 12 and stands more on one side than on the other. On the lid 17 are also a controller plug 43 and a tank return 32 arranged. A tank level sensor and preferably a quality sensor for the reducing agent may also be arranged in the installation module 4 not shown.

at a non-illustrated, airless system eliminates the mixing chamber and the air Elements.

A preferred dosing system arrangement is simplified in 5 shown. According to the invention, the metering system 12 as a built-in module 13 designed. In a tank room 11 the reducing agent for exhaust aftertreatment is stored for the purification of an exhaust gas of an internal combustion engine, which via a pump 18 and a unspecified line and a pre-filter 50 in a mixing chamber 19 can be introduced. In the pre-filter 50 the reducing agent is roughly purified. The pump 18 is with a bypass valve 51 bypassable, which at too high a pressure in a normal operation conveying direction 44 downstream of the pump 18 opens. The pump 18 promotes in the marked by an arrow normal operation conveying direction 44 to a mixing chamber 19 in which the reducing agent is prepared with aerosol assisted aerosol formation. The air supply from an air reservoir 52 is via an air control valve 20 and an air pressure sensor 36 controlled. As a further control element of the air supply in the direction of the mixing chamber 19 is a throttle 49 intended.

Downstream of the pump 18 is a filter 53 arranged, with which the reducing agent is cleaned, before it to the mixing chamber 19 arrives. Downstream of the filter 53 is a sensor 54 arranged for determining the reducing agent pressure, via an unspecified signal line with an engine control unit 55 connected is. Furthermore, with the engine control unit 55 a temperature sensor 56 coupled, the downstream of the sensor 54 is arranged and is provided for determining the temperature of the reducing agent. Between the pump 18 and the mixing chamber 19 are also a vent valve 57 and a metering valve 58 arranged.

For exhaust gas purification, the treated reducing agent from the mixing chamber 19 into a catalyst 60 brought in. An exhaust gas flow direction at the exhaust gas inlet portion 59 and at the exhaust outlet area 61 is indicated by arrows. At the exhaust inlet area 59 and at the exhaust outlet area 61 are usual sensors 62 and 63 provided, for example, pressure sensors, temperature sensors, lambda sensors, NOx sensors and the like., By means of unspecified signal lines to the control unit 55 are connected. The control unit 55 continues to control depending on operating parameters and / or operating conditions via unspecified signal lines the metering valve 58 as well as the pump 18 or their drive motor 45 at. Further, the controller 55 via a CAN bus 46 connected to the internal combustion engine of the vehicle. At the tank room 11 are sensors 64 and 65 provided for level measurement and for tank temperature measurement, by means of unspecified data lines with the control unit 55 are connected.

Claims (12)

Tank module for a reducing agent for the after-treatment of exhaust gases from an internal combustion engine, comprising at least one tank module housing ( 10 ), characterized in that within a tank chamber ( 11 ) of the tank module housing ( 10 ) a dosing system ( 12 ) is arranged for metering a reducing agent in an exhaust system. Tank module according to claim 1, characterized in that the dosing system ( 12 ) as a compact built-in module ( 13 ) is configured. Tank module according to one of the preceding claims, characterized in that the metering system ( 12 ) by means of a within the tank chamber ( 11 ) arranged heating device is heated. Tank module according to one of the preceding claims, characterized in that the metering system ( 12 ) by means of one within the tank chamber ( 11 ) arranged cooling system ( 16 ) is coolable. Tank module according to one of the preceding claims, characterized in that the metering system ( 12 ) a lid ( 17 ), with which the complete installation module ( 13 ) to the tank module housing ( 10 ) is flanged. Tank module according to one of the preceding claims, characterized in that the tank module housing ( 10 ) a fuel tank ( 14 ). Dosing system for supplying a reducing agent from a tank chamber into an exhaust system, characterized by a configuration as a built-in module ( 13 ). Dosing system according to claim 7, characterized in that in the installation module ( 13 ) at least partially on a printed circuit board ( 21 ) trained control components ( 22 . 36 . 41 . 42 . 54 . 55 . 56 . 62 . 63 . 64 . 65 ) are arranged. Dosing system according to claim 7 or 8, characterized in that at least one pump ( 18 ) and / or a dosing agent in the installation module ( 13 ) is provided. Dosing system according to one of claims 7 to 9, characterized in that at least one mixing chamber ( 19 ) and air supply elements ( 20 . 33 ) in the installation module ( 13 ) are summarized. Dosing system according to one of claims 7 to 10, characterized in that valves ( 20 . 23 . 51 . 57 . 58 ) are provided. Dosing system according to one of claims 7 to 11, characterized in that the installation module ( 13 ) a filter chamber ( 24 ).