DE102006036005B4 - Compressed air valve unit for an exhaust gas treatment device with urea for commercial vehicles - Google Patents

Abstract

The invention relates to a compressed air valve unit (1) for an exhaust gas treatment device for a commercial vehicle. According to the invention, a solenoid valve (9), a pressure limiting valve (7) and a check valve (8) are combined in a compressed air valve unit in a housing. This results in a compact compressed air valve unit (1), which can be interposed in a motor vehicle, in particular commercial vehicle, between a compressed air supply unit and an exhaust gas treatment device.

Description

TECHNICAL FIELD OF THE INVENTION

The The invention relates to a compressed air valve unit for an exhaust gas treatment device with urea for Commercial vehicles, in particular between a compressed air supply device or pipe and a urea misting device, exhaust gas treatment device or urea injector for an exhaust system of an internal combustion engine a commercial vehicle is interposed.

STATE OF THE ART

to Reduction of exhaust gases, in particular as a result of the introduced legal Standards "EURO 4", takes place as an alternative solution to a technology summarized under the keyword exhaust gas recirculation an exhaust aftertreatment, for the one additive, which also referred to as a reducing agent is, the exhaust gas of an internal combustion engine, in particular a diesel engine, supplied is, whereby an efficiency of a catalyst can be improved can and ultimately the relevant emissions of the internal combustion engine can be reduced to the environment. As an additive, for example, an aqueous urea solution is used since Urea is widely available, a harmless one Product represents a good adaptability to existing catalysts and possibly continuously for cars and commercial vehicles can be used. Such an aqueous urea solution is specified in DIN 70070.

Around to achieve a good distribution of the additive in the exhaust gas, this is injected using compressed air into an exhaust gas, injected or "fogged", including a provision required by compressed air.

Out DE 103 59 522 A1 For example, an exhaust treatment device is known which has an air supply module, an additive supply module and a metering module. An output line of the air supply module branches to a metered air line leading to the metering module and to a compressed air line leading to the additive supply module. The additive supply module is in turn connected via an additive line to the metering module. For dosing of the additive, the dosing module is supplied with dosing air from the air supply module via the dosing air line and with additive from the additional supply module via the additive line. From the metering module, the additive is finely distributed by means of the dosing air as needed fed via an adding device an exhaust pipe and a catalyst system. For example, the additive is a urea-water solution, and the catalyst system comprises a so-called SCR catalyst (Selective Catalytic Reduction Catalyst, cf. DE 297 08 591 U1 ).

According to the air supply module DE 103 59 522 A1 supply air is provided by a compressed air supply of the motor vehicle via an air supply line. This supplies the compressed air with a supply pressure of, for example, 8 bar. The air supply module includes an air supply valve, which is designed for the prior art as a 2/2-way solenoid valve. Furthermore, the air supply module comprises a pressure reducer with which the supply pressure is reduced to an operating pressure for the exhaust gas treatment device of, for example, 6 bar. The reduced to the operating pressure supply air is supplied via a branch on the one hand to the compressed air line and a valve assembly as compressed air to the additive supply module. On the other hand, it is fed via the dosing air as dosing the dosing.

The dosing module according to DE 103 59 522 A1 comprises a mixing chamber, which on the one hand the metering air via a Venturi nozzle and on the other hand, the reducing agent is supplied via a clocked metering valve. The Venturi nozzle serves to provide a uniform metered air flow. About a correspondingly controlled timing of the opening of the metering valve, the required amount of additive is supplied to the mixing chamber as needed. In the mixing chamber, a mixing and homogenization of the additive with the metering air, so that the generated air-additive mixture can be added via the above-mentioned adding device of the exhaust pipe. The metering module further comprises a first pressure sensor and a second pressure sensor for detecting the additive pressure in the additive line on the input side and the output side of the metering valve. The pressure signals of the pressure sensors are used for system control and for controlling the dosing process.

The additive supply module according to DE 103 59 522 A1 comprises a metering container for receiving the additive and an additive pump for filling the metering container with the additive on demand. In this case, the additive pump is connected via an additive supply line to an additive reservoir, not shown. Furthermore, a heating device is provided, through which the additive can be heated. From the dosing the metering valve of the dosing is supplied via a filter and the additive line with the additive. The metering container has, on the one hand, an additive volume and, on the other hand, an air volume which passes through a separating body, in particular a slidable stamp or a deformable or dense film, are separated.

A valve assembly according to DE 103 59 522 A1 comprises an air inlet valve and an air outlet valve, which are arranged in a parallel circuit in the compressed air line on the input side of the dosing. Between the valves and the metering a ventilation valve is also connected in the compressed air line. Preferably, the valves are designed as check valves with an adjustable bias. Further details on an operation of the pneumatic components and the function of the exhaust gas treatment device as well as a control of the compressed air flow, the additive stream and the compressed air-additive mixture stream are DE 103 59 522 A1 refer to.

Further prior art is out EP 1 435 458 A1 . DE 38 35 939 A1 and DE 100 47 512 A1 known.

OBJECT OF THE INVENTION

Of the present invention is based on the object, a structural unit to propose in connection with a needs-based provision a compressed air for an exhaust gas treatment device with urea for a motor vehicle is helpful.

SOLUTION

A solution the object underlying the invention is given by a Compressed air valve unit with the features of claim 1. Further Embodiments of such a solution arise accordingly the features of the claims 2 to 7. An alternative solution the object of the invention is based on the features of claim 8. Claims FIGS. 9 to 14 relate to further embodiments of this alternative solution according to the invention.

DESCRIPTION OF THE INVENTION

Of the The present invention is initially the Understanding, several pneumatic components in one unit summarize. This results in a cost-effective solution that allows easy installation, wherein the unit is supplied pre-assembled the motor vehicle or commercial vehicle can. Furthermore, it has been found that such a unit reliable may be pre-assembled, possibly also from a supplier. The space requirement of the participants involved can also be improved Components in a training as a separate unit.

Farther The invention is based on the knowledge, the unit as a compressed air valve unit form, in the essential elements for the design of the pneumatic conditions in the run-up to exhaust aftertreatment are summarized:

• - owns first the compressed air valve unit is a solenoid valve. About the solenoid valve, the the compressed air valve unit downstream exhaust treatment device in accordance with a control signal compressed air are supplied from a source or specifically the compressed air supply can be interrupted. At the control signal it is for example an electrical signal, which is generated by a suitable control device, wherein in the Control device, for example, a detected state of the exhaust gas, a Condition of a catalyst, operating characteristics of the exhaust gas generating Internal combustion engine o. Ä. considered becomes. For an exemplary embodiment of the additive as urea can a controller over it In addition, take into account a temperature of the urea, so that the compressed air supply via the Solenoid valve can be locked if the urea one for a reduction the exhaust gas has insufficient temperature. On the other hand, about the Solenoid valve, the supply of compressed air then be disabled when Such operating parameters of the internal combustion engine are present a reduction under circumstances is not required. It is also possible that in a control unit maps are present, in which a loading of the solenoid valve over the control unit dependent on the previously explained Company sizes can.
• - Farther is a pressure relief valve according to the invention intended. By using a pressure relief valve can the pressure at the outlet port is kept relatively constant or be kept below a threshold regardless of which pressure is applied to the input port of the compressed air valve unit. This allows also the volume flows and the mass flows the compressed air is relatively constant be kept, so that the compressed air of the exhaust treatment device is supplied in a defined state, so that injection conditions for the Additive can be kept constant and optimally designed can be. For the Case that the pressure applied to the input port is dependent from a conveyor state or a funding period a compressor or changeable Pressure fluctuations in a reservoir, such pressure changes by the compressed air valve unit according to the invention be decoupled.
• - The fact that according to the invention, a check valve is provided in addition in the compressed air valve unit, can be simple, but too reliable way can be avoided that exhaust gas and / or additive for pressure conditions, which favor a reflux, can be promoted to the input port of the compressed air valve unit. Such a reflux would have the consequence that components of the compressed air valve unit such as seals or the like and upstream of the compressed air valve unit arranged pneumatic components are affected by the possibly aggressive exhaust gases and / or the additive or particles can be deposited in such devices, which can lead to functional impairment ,

• – Ein von dem Sensor erfasster Druck, ein Massenstrom oder Volumenstrom kann geeignet in der Abgasbehandlungseinrichtung berücksichtigt werden, so dass die Verhältnisse zwischen der Druckluft und dem Zusatzstoff geeignet beeinflusst werden können und sich eine optimale Einspritzung oder Vermischung ergibt.
• – Andererseits kann über das Messsignals des Sensors eine Rückmeldung über eine Druckluftanforderung, beispielsweise von einem Reservoir oder einem Kompressor, gegeben werden, die indiziert, das unter Umständen eine verminderte oder erhöhte Kompressorleistung abgerufen werden muss.
• – Ebenfalls denkbar ist, dass über den Sensor ein Versagen eines pneumatischen Bauelementes detektiert wird, beispielsweise eine Leckage in einem pneumatischen Pfad zu der Abgasbehandlungseinrichtung.

According to a further embodiment of the invention, the housing has a sensor with which a detection of a pneumatic operating variable in the compressed air valve unit is possible. For example, the sensor detects a pressure in the compressed air valve unit and / or a flow variable, in particular a mass flow or a volume flow, in the compressed air valve unit. The sensor in this case preferably has an active surface which is exposed to the compressed air in the compressed air valve unit. The measurement signal generated by the sensor can be processed directly in the compressed air valve unit in a suitable control unit and / or be removed via an interface of the compressed air valve unit of this, for example, to an external control unit. The inventive integration of the sensor in the compressed air valve unit monitoring the pneumatic conditions in the compressed air valve unit is possible without the compactness of the compressed air valve unit is impaired. A signal of a sensor according to the invention can be used alternatively or cumulatively advantageously for different purposes, in particular:

• A pressure detected by the sensor, a mass flow or volume flow can be suitably taken into account in the exhaust gas treatment device, so that the relationships between the compressed air and the additive can be suitably influenced and optimum injection or mixing results.
• On the other hand, via the measuring signal of the sensor, a feedback via a compressed air requirement, for example from a reservoir or a compressor, can be given, which indicates that under certain circumstances a reduced or increased compressor output must be called up.
• - It is also conceivable that a failure of a pneumatic component is detected via the sensor, for example, a leakage in a pneumatic path to the exhaust gas treatment device.

For a further education the compressed air valve unit is in this in the housing a Throttle between input terminal and output terminal interposed. Over a Such throttle may be given given pneumatic input conditions the throttle constructive about the design of the throttle the resulting mass flow or volume flow pretend or be influenced. In addition, in case that two or more output ports on the compressed air valve unit are provided, the possibility given, over the equipment of one of the output terminals selectively with a throttle or more output ports with different throttles different pneumatic behaves Nisse at the output terminals to achieve. Thus, at each output terminal can specifically meet the requirements of downstream Building units of the exhaust treatment device are taken into account.

While quite possible is that the throttle as a constant throttle or as a manually adjustable is formed stepwise or continuous throttle, proposes a another embodiment the invention that the throttle controllable or adjustable (hereinafter also referred to as "controllable") formed is. As a result, in the compressed air valve unit the respective Operational requirements are taken into account. For such Control of the throttle can be integrated into the compressed air valve unit Control unit or an external control unit are used. Also is possible, that such a control signal a previously described Sensors processed and taken into account, which is integrated into the compressed air valve unit for detecting the pneumatic conditions, such as pressure, mass flow and / or volume flow. On the other hand, as mentioned earlier, the controllable throttle the requirements of the exhaust treatment device Take into account.

For one Another proposal of the invention is the compressed air valve unit equipped with a proportional valve, which in the housing between Input terminal and output terminal is interposed. About one Such proportional valve is an additional influence on the pneumatic Output variables of Compressed air valve unit possible, resulting in improved consideration requirements of the exhaust treatment device and the input side pressure conditions and the exhaust conditions of the internal combustion engine is possible.

An alternative solution of the object underlying the invention proposes that in a compressed air valve unit according to the invention a sensor is arranged between an input connection and an output connection, which sensor has a pressure and / or a flow variable such as a mass flow or a volumetric flow. detected. Furthermore, a controllable throttle is used, which is connectable or connected to a control unit. The control unit controls the controllable throttle suitably, taking into account the signal of the at least one sensor with regard to the pressure and / or the flow size. Such a configuration has the consequence that under certain circumstances can be dispensed with the use of a solenoid valve. Despite the saving of the solenoid valve can be taken on the inventive combination of the sensor with the controllable throttle influence on the flow conditions in the output region of the output terminal, which not only a "digital" opening and closing is possible.

While quite possible is that the controllable throttle controlling control unit externally of the compressed air valve unit is formed and via a suitable control line communicates with an interface of the compressed air valve unit, is for one Another proposal of the invention, the control unit in the housing of Compressed air valve unit provided so that is a compact but "intelligent" compressed air valve unit results. Continue to protect the housing the compressed air valve unit, the control unit, which may be sensitive having electronic components. On the other hand, unnecessary line connections over longer distances be avoided when sensor, the control unit and the of the Control unit controlled variable throttle in the compressed air valve unit are arranged.

For another Embodiment of the invention in one of the previously explained embodiments is in the case an overflow valve arranged between input terminal and output terminal. The overflow valve makes sure that it only with the crossing one of the overflow valve predetermined minimum threshold to a significant compressed air flow through the compressed air valve unit comes. The overflow valve can as such without Be formed backflow so this approximates a check valve forms and a possible check valve can replace. For an embodiment of the overflow valve has limited backflow the overflow valve a hysteresis. Also possible is the use of an overflow valve with unlimited backflow.

For a further education The invention relates to the compressed air valve unit and the exhaust gas treatment device with a common housing equipped, so that with these two components a compact Unity can result. As a result, weight and space can be saved become. Furthermore, transmission paths saved between the compressed air valve unit and the exhaust gas treatment device be omitted and any fasteners.

One Another proposal of the invention provides that the compressed air valve unit in a compressed air procurement plant, compressed air treatment plant and Compressed air supply system (hereinafter "compressed air supply device") is integrated. hereby can be a summary of functionally identical components, for example Valves, in one unit, namely the compressed air supply device, done. The compressed air supply device can then with the compressed air valve unit contained herein as one Unit manufactured and delivered, possibly by a supplier. Also a mounting in a motor vehicle or commercial vehicle can be simplified in this way.

Examples of compressed air supply facilities in which the compressed air valve unit can be integrated, are in the publications DE 196 38 226 C1 . DE 103 14 643 B4 and DE 103 38 162 B3 disclosed, which serve for the compressed air supply of several consumer circuits of a motor vehicle. Also possible is the substantially identical design of a first group of compressed air supply units and a second group of compressed air supply units, although for the second group an unused for the first group output terminal with the compressed air valve unit according to the invention is pressurized air. As a result, a production of a large number of the same compressed air supply units when needed adjustment by the compressed air valve unit is possible if for vehicles with compressed air supply devices of the second group should be followed by exhaust aftertreatment. For an exemplary integration, reference is also made to the Applicant's patent application with the same filing date as the present application and entitled "Compressed Air Supply Unit".

Used according to the invention Control units can be associated with the compressed air valve unit, so that the control unit signals are supplied internally in the compressed air valve unit can and / or signal connections of the Compressed air valve unit supplied become. Control signals can also run internally in the compressed air valve unit or via output terminals of Compressed air valve unit to be transferred to adjacent units. Also possible is a cross-linking of the compressed air valve unit with other control units, in particular via a CAN bus, where the compressed air valve unit is completely formed without its own control unit can be or over have their own control unit can.

• – Betriebssignale wie eine Leistungsanforderung, eine Kraftstofftemperatur, ein Kraftstoffbewertungsparameter, Abgasbewertungsparameter, Betriebsparameter der Brennkraftmaschine wie eine Drehzahl, Drehmoment, eine Drosselklappenstellung, Öffnungs- und Schließparameter der Ventile der Brennkraftmaschine, Schaltzustände eines Getriebes, Abgasmesswerte wie Drücke, Temperaturen oder Abgaszusammensetzungen, Zustandsparameter des Katalysators wie dessen Wirkungsgrad, Messwerte von Lambda-Sonden vor, in und/oder hinter dem Katalysator u. ä.,
• – Fahrerparameter wie beispielsweise eine Leistungsanforderung, Zündsignale, Fahrertypparameter wie "ruhiger Fahrer" oder "aggressiver Fahrer", Leerlaufparameter, Schaltzustände eines Getriebes, Abschaltsignale für die Brennkraftmaschine, Betätigungen von Zusatzaggregaten u. ä. und/oder
• – Umgebungsparameter wie eine aktuelle oder antizipierte Fahrbahnneigung, eine geodätische Höhe, ein Luftdruck, eine Außentemperatur u. ä.

zur Ermittlung der an dem Ausgangsanschluss der Druckluftventileinheit vorherrschenden pneumatischen Sollbedingungen und damit zur Ermittlung der Betätigungsbedingungen für die pneumatischen Bauelemente der Druckluftventileinheit.For controlling or regulating the compressed air valve unit, it is advantageous if in at least ei ner of the aforementioned control units signals are considered as:

• Operating signals such as a power demand, a fuel temperature, a fuel evaluation parameter, exhaust gas evaluation parameter, engine operating parameter such as a rotational speed, torque, throttle position, internal combustion engine opening and closing parameters, gear shift states, exhaust gas measurement values such as pressures, temperatures or exhaust gas compositions, catalyst condition parameters as its efficiency, measured values of lambda probes before, in and / or behind the catalyst u. ä.,
• Driver parameters such as a power demand, ignition signals, driver type parameters such as "quiet driver" or "aggressive driver", idle parameters, switching states of a transmission, shutdown signals for the internal combustion engine, actuation of additional equipment u. Ä. and / or
• - Environmental parameters such as a current or anticipated road gradient, a geodetic altitude, an air pressure, an outside temperature u. ä.

for determining the pneumatic nominal conditions prevailing at the outlet connection of the compressed-air valve unit and thus for determining the operating conditions for the pneumatic components of the compressed-air valve unit.

Of the or the output terminals the compressed air valve unit can / for a control pressure of the exhaust gas treatment device be used and / or, at least in partial operating areas, to Compressed air supply of the exhaust gas treatment device with a habhaften Compressed air stream.

advantageous Further developments of the invention will become apparent from the claims, the Description and the drawings. The in the introduction to the description advantages of features and combinations of several Features are merely exemplary and may be alternative or cumulative come into effect, without the benefits of mandatory embodiments of the invention must be achieved. Other features are the drawings - in particular the illustrated Geometries and the relative dimensions of several components to each other as well as their relative arrangement and operative connection - can be seen. The combination of features of different embodiments the invention or features of different claims is also different from the ones chosen The antecedents of the claims possible and is hereby stimulated. This also applies to such features as in separate drawings are shown or in their description to be named. These features can be combined with features of different claims. As well can in the claims listed Features for more embodiments the invention omitted.

BRIEF DESCRIPTION OF THE FIGURES

 It demonstrate:

1 a schematic representation of a pneumatic assembly, which is interposed between a compressed air supply device and an exhaust gas treatment device;

2 a schematic representation of a compressed air valve unit according to the invention with a solenoid valve, a check valve and a pressure relief valve, an input port and two output ports;

3 a schematic representation of a compressed air valve unit according to the invention with a check valve, a variable throttle and two sensors;

4 a structural design of a compressed air valve unit according to the invention with a solenoid valve, a pressure relief valve and a check valve with open pressure relief valve;

5 the compressed air valve unit according to 4 with closed pressure relief valve;

6 an alternative structural design of a compressed air valve unit according to the invention with a solenoid valve, a check valve, a pressure relief valve and a spill valve, wherein the spill valve is in the closed state;

7 the compressed air valve unit according to 6 , wherein the overflow valve and the pressure relief valve are in the open state;

8th the compressed air valve unit according to 6 , wherein the overflow valve is in the open state and the pressure relief valve is in the closed state.

DESCRIPTION OF THE DRAWINGS

The Invention finds application in a vehicle with a compressed air system, in particular a passenger car or a commercial vehicle. Especially is such a vehicle with a diesel engine and a catalytic converter fitted.

In such a vehicle is an inven The proper compressed air valve unit 1 between a compressed air supply unit and an exhaust gas treatment device interposed, wherein the exhaust gas treatment device of a change in the composition of an exhaust gas of the internal combustion engine is used to reduce emissions of pollutants in the environmental and / or influencing the performance of a downstream of the exhaust gas treatment device arranged catalyst. For this purpose, by the exhaust gas treatment device, a mixing of compressed air, by the compressed air valve unit according to the invention 1 passed and brought into the correct pneumatic state, and an additive, in particular urea, and the exhaust gas brought about. In the illustrated figures is only one input terminal 2 the compressed air valve unit, which is optionally connected with the interposition of further pneumatic components, with a compressed air supply unit, and an output terminal which is connected, in particular with the interposition of further pneumatic components, with the exhaust gas treatment device.

1 shows a supply of a reservoir 4 by a compressed air supply unit, not shown, with compressed air. The reservoir 4 is over a line 5 with an overflow valve 6 connected, which via a pressure relief valve 7 , a check valve 8th and a solenoid valve 9 with the output line 10 connected is. The solenoid valve 9 , which is designed for example as a 2/2-way valve or 3/2-way valve, can be brought electrically in two switching positions, wherein in the illustrated switching position, the output line 10 is vented while in the switching position, not shown, the line connection between the check valve 8th and output line is given.

2 shows a summary of pneumatic components in a housing 11 to a compressed air valve unit 1 , In the case 11 are between an input terminal 12 and an output terminal 13 the solenoid valve 9 , the check valve 8th and the pressure relief valve 7 connected in series in pneumatic series in the above order, with a different order of said pneumatic components is possible. Optionally, as in 2 already shown, the pressure relief valve 7 a branch 14 be downstream of the pneumatic path on two lines 15 . 16 branches, with the first line 15 with the output connector 13 connected while the second line 16 with the interposition of an adjustable throttle 17 with another output connection 18 connected is. The two output connections 13 . 18 allow a different pneumatic loading of components of the exhaust treatment device. For example, it is possible that compressed air is blown into the exhaust gas from an output port, while use is made of another output port for injection or turbulence of compressed air and additive before or with introduction into the exhaust gas or the other output port provides a control pressure for the exhaust treatment device ,

3 shows an alternative embodiment of a compressed air valve unit 1 , This one is in the case 11 the compressed air valve unit 1 between input connection 12 and output connection 13 a check valve and an electrically adjustable throttle 17 interposed. Downstream of the throttle 17 is in the housing via sensors 19 . 20 a pressure and a flow variable, in particular a mass flow and / or a volume flow detected. The output signals of the sensors 19 . 20 be via interfaces 21 . 22 a control unit 23 supplied, which generates a control signal, with which via an interface 24 the compressed air valve unit 1 the adjustable throttle 17 is suitably controlled. To determine the control signal, the control unit 23 Further signals or operating variables, for example, a temperature of the additive, the operating conditions of the internal combustion engine such as power demand, speed, torque, vehicle speed, emissions, catalytic converter values, an ambient pressure, a throttle angle, predictive values about a future driving state, an ambient temperature or the like are supplied. It is also possible that the interfaces on the compressed air valve unit 21 . 22 . 24 are combined to a common interface or a suitable port. Also possible is a communication of the compressed air valve unit 1 with a control unit or adjacent components of the vehicle via a CAN bus. In addition to the illustrated embodiment, for which the control unit 23 separate from the compressed air valve unit 1 is formed, it is also possible that the control unit 23 in the case 11 is integrated.

4 shows a longitudinal section through a structural design of a compressed air valve unit according to the invention 1 , A housing 59 is formed in the illustrated longitudinal section in a first approximation as U-shaped lying in the figure U with a limited by the U-shaped longitudinal section recess 25 which has several stages. In the area of the lower side leg of the U has the housing 59 the input terminal 12 in which a thread 26 over a hole 27 with reduced diameter in an annulus 28 opens, which is bounded radially outwardly of the side legs of the housing 59 as well as in both directions of a longitudinal axis 29 - 29 and radially inwardly from a circumferential groove of an insert 30 in the Ausneh mung 25 , Between the annulus 28 and the solenoid valve 9 is a conduit with one from the annulus 28 radially inwardly leading transverse channel 31 and one the cross channel 31 with the solenoid valve 9 connecting longitudinal channel 32 educated. From the solenoid valve 9 leads another longitudinal channel 33 to a chamber 34 the pressure relief valve 7 , In the event that the solenoid valve 9 is designed as a 2/2-way valve, this can in the switch positions the longitudinal channels 32 . 33 connect and disconnect. For an alternative embodiment has the solenoid valve 9 a vent port 35 , so that this can be designed as a 3/2-way valve. The chamber 34 and the solenoid valve 9 are aligned with each other and from the insert 30 on both sides or one-sided in the direction of the longitudinal axis 29 - 29 and limited in the radial direction. The chamber 34 goes over into another mission 36 , which is also under radial sealing in the recess 25 is used. In the chamber 34 is via a compression spring 37 a valve body 38 on the solenoid valve 9 facing away from a valve seat 39 of the insert 36 pressed. According to 4 is the valve body 38 opposite the valve seat 39 in an open position while according to 5 the valve body 38 the valve seat 39 closes. Centric through the valve seat 39 through a sleeve extends 40 , The sleeve 40 lies with its front side on the valve body 38 at. The sleeve 40 carries in the end area, which on the the solenoid valve 9 opposite side from the insert 36 protrudes, a servo piston 41 , which lies radially outward with the interposition of a sealing ring 42 opposite the recess 25 is sealed and on which a compression spring 43 supported between the actuator piston 41 and another, in the region of the lower end portion of the housing 59 firmly supported plate 44 is clamped. The sleeve 40 has in the area of its lateral surface the check valve 8th which is formed in this case as an overflow lip, which in the direction of the output terminal 13 opens and closes in the opposite direction.

In 4 is the compressed air valve unit 1 shown in a state for which pressurization begins or at the input port 12 applied pressure is less than the pressure applied to the output port. In this state, the pressure relief valve 7 , which with the valve seat 39 and the valve body is formed, opened. For a higher pressure at the input connection 12 shows 5 the closed pressure relief valve 7 ,

• – der Druck der Kammer 47 über den Stellkolben 41,
• – die Federkraft der Druckfeder 43 und
• – eine Kraft infolge des gleichen Drucks in den Kammern 34, 47 mit unterschiedlichen Wirkflächen.

According to the in 4 shown switching state occurs compressed air from the input port 12 over the hole 27 in the annulus 28 in and out of the canals 31 . 32 with open solenoid valve 9 in the channel 33 as well as the chamber 34 , Between the valve body 38 and the radial boundary of the chamber 34 is an annular gap 45 formed so that the compressed air into a below the valve body 38 lying sub-chamber 46 the chamber 34 can occur and over a between sleeve 40 and use 36 formed hollow cylindrical channel under overflow of the check valve 8th to a chamber 47 can flow between uses 36 and actuator piston 41 is formed and from the compressed air to the output port 13 arrives. On the sleeve 40 Act

• - the pressure of the chamber 47 over the adjusting piston 41 .
• - The spring force of the compression spring 43 and
• A force due to the same pressure in the chambers 34 . 47 with different effective surfaces.

According to 4 is the pressure in the chamber 47 and thus the input-side pressure insufficient to the actuator piston 41 under pressure of the compression spring 43 to move to the left. With an increase in pressure in the area of the input terminal 12 can by moving the actuator piston 41 , the sleeve 40 and the valve body of in 5 shown state be brought about. As with the actuator piston 41 also the sleeve 40 Moved to the left, the valve body can 38 under seal on the valve seat 39 come to rest, so that in the area of the pressure relief valve 7 the connection between input terminal 12 and output connection 13 can be separated.

The housing 59 still has holes 48 . 49 , about which the compressed air valve unit 1 can be attached to a further component of the vehicle, for example to a part of the exhaust system, a holding element for an element of the exhaust system, to the catalyst, to the exhaust gas treatment device, a Druckluftbereitstellungseinheit, on a vehicle longitudinal or cross member o.

In the in 5 shown position is the actuator piston 41 in closed position. The valve body 38 seals on the valve seat 39 off so that chamber 34 from chamber 47 is disconnected and no further pressure increase can take place. On both sides of the annulus 28 is the use 30 over sealing rings 51 . 52 sealed. Also the use 36 has radially outboard a sealing ring 53 , the chamber 34 to chamber 47 seals.

For the in 6 illustrated, structurally executed variant of the compressed air valve unit 1 has this in addition to the embodiment according to 4 an overflow valve 54 , The use 30 is in this case with one opposite 4 deviating geometry is formed, but also has an annulus 28 , Channels 31 . 32 to the solenoid valve 9 and a longitudinal channel 33 from the solenoid valve 9 to the chamber 34 a pressure limiting valve tils 7 with a compression spring 37 and a valve body 38 , Also, the associated valve seat 39 from another mission 36 formed in this case, however, under sealing in the direction of the longitudinal axis 29 - 29 opposite the insert 30 is displaceable. Through the further use 36 extends accordingly 4 the sleeve 40 that in one out of use 36 projecting end portion of the actuator piston 41 carries that over the sealing ring 42 is sealed against the recess and on which the compression spring 43 supported. The operation of the pressure relief valve formed in this way 7 corresponds to the according to 4 , Between the insert 30 and the shiftable against this use 36 is the overflow valve 54 educated.

From the input port 12 the compressed air passes over the hole 27 in an annulus 55 one in between the insert 30 and the housing 59 is formed and over the sealing rings 51 . 52 is sealed. From the annulus 55 can the compressed air through one or more cross holes 60 of the insert 30 pass through to another annular chamber 56 , from where the compressed air with the interposition of the designed as a sealing lip check valve 8th in another annular chamber 61 can transgress. The annular chamber 61 is over the overflow valve 54 connected to one or more cross bores 57 in the annulus 28 lead.

About the annulus 28 can the compressed air through channels 31 . 32 . 33 with the interposition of the solenoid valve 9 the chamber 34 be fed and over the annular gap 45 the sub-chamber 46 be supplied. From the sub-chamber 46 can the compressed air for open pressure relief valve 7 over a gap 62 that is between the insert 36 and sleeve 40 as well as actuator piston 41 is formed, via suitable crossover cross sections 58 to the output terminal 13 reach.

6 shows the compressed air valve unit 1 with closed overflow valve 54 , In this state, the spring force of the compression spring 43 that via the actuator piston 41 on the insert 36 greater than the force due to the inlet pressure in the annular chamber 61 on the insert 36 acts. For this reason, use with the valve seat against a nose 63 of the insert 30 pressed so that the overflow valve 54 closed is.

If the inlet pressure exceeds a structurally specified threshold value, the overflow valve opens 54 by relative movement to it to rest on a stop disc 64 between use 30 and actuator piston 41 with use 36 ( 7 ), so that in the area of the nose 63 an opening cross section is formed. With appropriate position of the solenoid valve 9 thus comes in accordance with 7 Compressed air from the input port 12 over the hole 27 , the annulus 55 , the transverse bore 60 , the ring chamber 56 , the check valve 8th , the ring chamber 61 , the opened overflow valve 54 , the transverse bore 57 , the annulus 28 , Channels 31 . 32 , Switching valve 9 , Channel 33 , Chamber 34 , Annular gap 45 , Sub-chamber 46 , Space 62 , Cross section 58 to the output terminal 13 ,

According to the in 4 and 5 illustrated embodiment includes according to 8th the pressure relief valve 7 when the pressure force due to the on the valve body 38 and the actuator piston 41 acting pressure is greater than the spring force of the compression spring 43 ,

1

Pneumatic valve unit

2

input port

3

output port

4

reservoir

5

input line

6

overflow

7

Pressure relief valve

8th

check valve

9

magnetic valve

10

output line

11

casing

12

input port

13

output port

14

branch

15

management

16

management

17

adjustable throttle

18

Second output port

19

sensor

20

sensor

21

interface

22

interface

23

control unit

24

interface

25

recess

26

thread

27

drilling

28

annulus

29

longitudinal axis

30

commitment

31

Querkanal

32

longitudinal channel

33

longitudinal channel

34

chamber

35

exhaust port

36

commitment

37

compression spring

38

valve body

39

valve seat

40

shell

41

actuating piston

42

seal

43

compression spring

44

Plate

45

annular gap

46

member chamber

47

chamber

48

drilling

49

drilling

50

attack

51

seal

52

seal

53

seal

54

overflow

55

annulus

56

annular chamber

57

cross hole

58

Transfer cross section

59

casing

60

cross hole

61

annular chamber

62

gap

63

nose

64

stop disc

Claims (14)

Compressed air valve unit ( 1 ) with a housing ( 11 ), an input terminal ( 12 ) and an output terminal ( 13 ), which is used for the compressed air supply of an exhaust gas treatment device, in which an additive-compressed air mixture is prepared for an exhaust system of a motor vehicle, characterized in that in the housing ( 11 ) the input terminal ( 12 ) with the interposition of a solenoid valve ( 9 ), a pressure relief valve ( 7 ) and a check valve ( 8th ) with an output terminal ( 13 ) connected is. Compressed air valve unit ( 1 ) according to claim 1, characterized in that the housing ( 11 ) a sensor ( 19 . 20 ) for detecting a pneumatic operating variable in the compressed air valve unit ( 1 ). Compressed air valve unit according to claim 2, characterized in that the sensor ( 19 . 20 ) a pressure in the compressed air valve unit ( 1 ) detected. Compressed air valve unit ( 1 ) according to claim 2 or 3, characterized in that the sensor ( 19 . 20 ) detects a flow quantity in the compressed air valve unit. Compressed air valve unit ( 1 ) according to one of the preceding claims, characterized in that in the housing ( 11 ) a throttle between input terminal ( 12 ) and output terminal ( 13 ) is interposed. Compressed air valve unit according to claim 5, characterized in that the throttle as controllable or controllable throttle ( 17 ), which in particular takes into account one of a sensor ( 19 . 20 ) is controlled or regulated according to one of claims 2 to 4 detected pneumatic operating variable. Compressed air valve unit ( 1 ) according to one of the preceding claims, characterized in that in the housing ( 11 ) a proportional valve between input port ( 12 ) and output terminal ( 13 ) is interposed. Compressed air valve unit ( 1 ) with a housing ( 11 ), an input terminal ( 12 ) and an output terminal ( 13 ), which serves to supply compressed air to an exhaust gas treatment device, in which an additive-compressed air mixture is prepared for an exhaust system of a motor vehicle, characterized in that the input connection ( 12 ) with the interposition of a sensor ( 19 . 20 ) for detecting a pressure or other flow variable, a controllable throttle ( 17 ) and a check valve ( 8th ) with the output terminal ( 13 ), the controllable throttle ( 17 ) with a control unit ( 23 ) is connectable or connected via which the throttle ( 17 ) taking into account the signal of the sensor ( 19 . 20 ) is controllable. Compressed air valve unit ( 1 ) according to claim 8, characterized in that the control unit ( 23 ) in the housing ( 11 ) is provided. Compressed air valve unit ( 1 ) according to one of the preceding claims, characterized in that in the housing ( 11 ) an overflow valve ( 6 ; 54 ) between input terminal ( 12 ) and output terminal ( 13 ) is interposed. Compressed air valve unit ( 1 ) according to one of the preceding claims, characterized in that the housing ( 11 ) is attached to an exhaust system or in the immediate vicinity of the same. Compressed air valve unit ( 1 ) according to one of the preceding claims, characterized in that the housing ( 11 ) is attachable to an exhaust treatment device. Compressed air valve unit ( 1 ) according to one of the preceding claims, characterized in that the compressed air valve unit ( 1 ) and the exhaust treatment device have a common housing. Compressed air supply device with a compressed air valve unit according to one of the preceding claims.