DE102008039922A1 - Valve for fluid system has two terminals designed in hollow cylindrical manner, where valve member is designed for pneumatic or hydraulic coupling of two terminals - Google Patents

Abstract

The valve (28) has two terminals designed in a hollow cylindrical manner, where a recess is provided at a free axial end of the latter terminal for dosing of fluid (FL). A valve member is designed for pneumatic or hydraulic coupling of the two terminals. An electromagnet is designed to drive the valve member, and is thermally coupled with the latter terminal. An independent claim is included for a fluid system.

Description

The The invention relates to a valve and a fluid system.

to Compliance with legal restrictions on pollutant emissions During operation of internal combustion engines, resulting exhaust gas can be aftertreated become. In particular, efforts are made in the exhaust gas contained nitrogen oxides to harmless substances react. This type of pollutant reduction is, for example, in diesel internal combustion engines applied and carried out in a special catalytic converter. The exhaust gas catalyst is preferably an SCR catalyst of SCR system. SCR in this context means "selective catalytic reduction ".

In The exhaust gas of an internal combustion engine contained nitrogen oxides can be degraded by means of ammonia, during operation the internal combustion engine obtained from a special ammonia medium becomes. The special ammonia medium can be an aqueous urea solution be. For exhaust aftertreatment is the urea solution of the SCR catalyst is metered into the exhaust gas flow of the internal combustion engine. For example, the urea solution has a freezing temperature from -11 ° C to.

at low ambient temperatures can be the urea solution freeze in the SCR system. This can cause that a metering of the urea solution in the exhaust stream of Internal combustion engine at least temporarily not possible and as a result a reduction of nitrogen oxides does not take place. Furthermore, the SCR system can be formed by ice formation of the urea solution to be harmed.

The Task underlying the invention is a valve and a To create a fluid system that is cost effective and reliable are formed.

The Task is solved by the characteristics of the independent Claims. Advantageous embodiments of the invention are specified in the dependent claims.

According to one First aspect, the invention is characterized by a valve with a first terminal and a second terminal, the second one Terminal is designed as a hollow cylinder and at his free axial end has a recess for metering fluid. A valve member is designed for pneumatic and / or hydraulic Coupling of the first connection with the second connection. An electromagnet is designed to drive the valve member and is thermally coupled at least with the second connection. This allows a inexpensive and reliable trained valve by the thermal coupling of the electromagnet at least with the second connection in that by means of the one electromagnet freezing fluid in at least the second port effectively can be avoided.

In In an advantageous embodiment, the second connection has a annular circumferential projection on. this makes possible a simple hydraulic and / or pneumatic coupling of the valve, for example with a fluid line.

According to a further advantageous embodiment, the second connection is formed according to the Norm J2044 the Society of Automotive Engineers. By the means of the second connection predetermined very simple interface system costs can be reduced in this way by a cost-effective possibility of hydraulic and / or pneumatic coupling.

In a further advantageous embodiment is at least the second Connection made of stainless steel. This allows effective a thermal coupling of the electromagnet with the second terminal.

According to one second aspect, the invention is characterized by a fluid system with a fluid reservoir, a valve and a first fluid line. The first fluid line is hydraulically and / or pneumatically coupled with the fluid reservoir via a withdrawal port for Removal of fluid. Furthermore, the first fluid line is hydraulic and / or pneumatically coupled to a fluid inlet of a fluid pump and with the valve. The valve is designed and arranged for Supplying gas to the first fluid line dependent from its valve position. The fluid pump is hydraulic and / or pneumatically coupled via a fluid outlet to the injector via a second fluid conduit for metering fluid. this makes possible a reliably formed fluid system in that the fluid system can be emptied by means of the valve and thereby damage, which can be caused for example by frost effect, can be effectively avoided.

In an advantageous embodiment, a further valve is formed and arranged for hydraulic and / or pneumatic coupling the second fluid line with the fluid reservoir. this makes possible emptying the fluid system of fluid into the fluid reservoir.

According to a further advantageous embodiment, the further valve is arranged for the hydraulic and / or pneumatic coupling of the second fluid line with the fluid reservoir via a metering connection for metering fluid into the fluid idreservoir.

In A further advantageous embodiment is an additional valve formed and arranged for supplying gas to the second fluid line depending on its valve position. This effectively allows pressure equalization in one Area of the fluid system between the injector, the valve and the Fluid pump.

According to one Another advantageous embodiment is the fluid inlet of the fluid pump hydraulically and / or pneumatically coupled with a fluid filter. This allows a reliably designed fluid system in that impurities of the fluid are effectively removed from the fluid pump can be kept away.

embodiments The invention are described in more detail below with reference to the schematic drawings explained.

It demonstrate:

1 a fluid system and an internal combustion engine,

2 a valve.

elements the same construction or function are cross-figurative provided with the same reference numerals.

1 shows an internal combustion engine 2 with a throttle 4 , an intake stroke 6 , an engine block 8th and an exhaust tract 10 , In the internal combustion engine 2 it may be, for example, a diesel engine. The engine block 8th includes a combustion chamber 12 , Cylinder heads 14 and injectors 16 , The exhaust tract 10 includes a catalyst 18 ,

With the catalyst 18 it may, for example, be an SCR catalyst for the reduction of nitrogen oxides. To reduce nitrogen oxides, a hot exhaust gas flow of the internal combustion engine 2 by means of a fluid system 19 a urea solution are metered.

The fluid system 19 includes a fluid reservoir 20 for storing a fluid FL, for example ammonia-containing urea solution, with a withdrawal port 21a and a metering connection 21b , Furthermore, the fluid system comprises 19 a fluid pump 22 with a fluid inlet 22a and a fluid outlet 22b for removing fluid FL from the fluid reservoir 20 via a first fluid line 24 , Via the fluid outlet 22b and a second fluid line 25 The fluid FL can be used as an injector 26 be directed by means of the fluid FL in the exhaust tract 10 the internal combustion engine 2 is measured.

The fluid reservoir 20 is with the fluid inlet 22a the fluid pump 22 coupled via the withdrawal port 21a and the first fluid line 24 , The injector 26 is with the fluid outlet 22b the fluid pump 22 coupled via the second fluid line 25 , In a preferred embodiment, the fluid pump 22 in front of the fluid inlet 22a a fluid filter 27 upstream.

To freeze the fluid FL in the fluid system 19 At low ambient temperatures to prevent, for example, a motor stall, the first fluid line 24 and the second fluid line 25 be discharged from the fluid FL. The emptying of the first fluid line 24 and the second fluid line 25 For example, after a shutdown of the engine 2 be made, wherein the fluid FL after switching off the internal combustion engine 2 For example, in the exhaust system 10 can be measured. For emptying the first fluid line 24 and the second fluid line 25 in the exhaust tract 10 is the first fluid line 24 coupled with a valve 28 configured to supply gas to the first fluid conduit 24 depending on its valve position.

During operation of the internal combustion engine 2 are the first fluid line 24 and the second fluid line 25 filled with the fluid FL, for example, the urea solution. The first fluid line 24 couples the fluid reservoir 20 via the extraction connection 21a in this case hydraulically with the fluid inlet 22a the fluid pump 22 , For emptying, while the fluid pump is running 22 the valve 28 open, leaving first the first fluid line 24 and over the first fluid line 24 the second fluid line 25 Gas is supplied, which displaces the fluid FL. Is the injector located 26 in an open position, the fluid FL is in the exhaust tract 10 repressed. At least for a completely empty first fluid line 24 can be spoken of a pneumatic coupling between the valve 28 , the extraction connection 21a of the fluid reservoir 20 and the fluid inlet 22a the fluid pump 22 , The second fluid line 25 is pneumatically coupled to the fluid outlet after draining Fluid FL 22b , the fluid pump 22 and the injector 26 ,

In a preferred embodiment, the fluid FL becomes the first fluid conduit 24 and the second fluid line 25 at least at the engine stall of the internal combustion engine 2 not in the exhaust tract 10 but in the fluid reservoir 20 meted out. There is another valve for this 30 provided at a branch of the second fluid line 25 is arranged to this with the metering connection 21b of the fluid reservoir 20 to pair. To empty the first fluid line 24 and the second fluid line 25 in the fluid reservoir 20 be both the valve 28 as well as the other valve 30 opened and the injector 26 closed so that while the fluid pump is running 22 the fluid FL through the gas in the first fluid line 24 and the second fluid line 25 displaced and the fluid reservoir 20 is measured.

In a preferred embodiment, an additional valve 32 arranged to supply gas to the second fluid line 25 depending on its valve position. By means of the additional valve 32 is a pressure equalization in the second fluid line 25 possible.

To form a reliable fluid system 19 are the valve 28 , the more valve 30 as well as the additional valve 32 heated. In the following, details will be explained using the in 2 shown valve 28 exemplary also for the other valve 30 as well as the additional valve 32 explained in more detail:
The valve 28 includes a valve housing 34 with a first connection 36a and a second port 36b and one the valve 28 between the first connection 36a and the second port 36b penetrating axial cavity 37 , Between the valve body 34 and a free axial end of the first terminal 36a is a sealing ring 38 arranged. The second connection 36b is hollow cylindrical and has at its free axial end a recess 39 on for metering fluid FL. In a preferred embodiment, the second port is 36b trained after the Norm J2044 the Society of Automotive Engineers, called SAE, and has an annular circumferential projection 40 on. In a preferred embodiment, the second port is 36b made of stainless steel.

In the axial cavity 37 is a filter housing 42 with a filter 44 arranged to filter the fluid FL. Further, in the axial cavity 37 an inner housing 46 and a spring seat 48 with a return spring 50 arranged. The return spring 50 is under a bias between the spring seat 48 and a needle seat 52 , which is mechanically coupled with a valve needle 54 , When the valve is not actuated, the valve needle stops 54 one with the valve needle 54 mechanically coupled valve member 56 that in a valve body 58 is arranged, in a closed position.

The valve 28 is designed for pneumatic and / or hydraulic coupling of the first terminal 36a with the second connection 36b through the valve member 56 , The valve member 56 is controlled via the valve needle 54 by means of an electromagnet 60 , The electromagnet 60 is electrically coupled to an electrical connection 62 , Upon application of the electromagnet 60 with electrical energy via the electrical connection 62 the valve member acts 56 over the valve needle 54 on a ball 64 who is in a seat 66 in the axial cavity 37 located and the first connection 36a pneumatically and / or hydraulically with the second port 36b coupled.

When controlling the electromagnet 60 a current flows through the electromagnet 60 so that the electromagnet 60 heated due to its ohmic resistance. By the thermal coupling of the electromagnet 60 with the second connection 36b will be at least the second port 36b through the electromagnet 60 also heated. This allows a reliable trained valve 28 in that, for example, freezing of fluid FL in the second port 36b can be effectively avoided. Furthermore, the thermal coupling allows a cost-effective designed valve 28 in that on an additional separate heat source at the second port 36b can be waived.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - standard J2044 [0009]
• - standard J2044 [0029]

Claims (9)

Valve ( 28 ), with - a first connection ( 36a ), - a second connection ( 36b ), which is hollow cylindrical in shape and at its free axial end a recess ( 39 ) for metering fluid (FL), - a valve member ( 56 ), which is designed for the pneumatic and / or hydraulic coupling of the first terminal ( 36a ) with the second connection ( 36b ) and - an electromagnet ( 60 ), which is designed to control the valve member ( 56 ) and which is thermally coupled at least to the second terminal ( 36b ). Valve ( 28 ) according to claim 1, wherein the second connection ( 36b ) an annular peripheral projection ( 40 ) having. Valve ( 28 ) according to one of the preceding claims, in which the second connection ( 36b ) is designed according to the J2044 standard of the Society of Automotive Engineers. Valve ( 28 ) according to one of the preceding claims, in which at least the second connection ( 36b ) is formed of stainless steel. Fluid system, with - a fluid reservoir ( 20 ), - a valve ( 28 ), which is formed according to one of the preceding claims, - a first fluid line ( 24 ), which is hydraulically and / or pneumatically coupled to the fluid reservoir ( 20 ) via a withdrawal port ( 21a ) for the removal of fluid (FL), with a fluid inlet ( 22a ) a fluid pump ( 22 ) and with the valve ( 28 ), - the valve ( 28 ) is arranged and arranged for supplying gas to the first fluid line ( 24 ) depending on its valve position, - the fluid pump ( 22 ), which via a fluid outlet ( 22b ) is hydraulically and / or pneumatically coupled to the injector ( 26 ) via a second fluid line ( 25 ) for metering fluid (FL). Fluid system according to claim 5, wherein a further valve ( 30 ) is formed according to one of claims 1 to 4 and arranged for hydraulic and / or pneumatic coupling of the second fluid line ( 25 ) with the fluid reservoir ( 20 ). Fluid system according to claim 6, wherein the further valve ( 30 ) is arranged for the hydraulic and / or pneumatic coupling of the second fluid line ( 25 ) with the fluid reservoir ( 20 ) via a metering connection ( 21b ) for metering fluid (FL) into the fluid reservoir ( 20 ). Fluid system according to one of claims 6 or 7, in which an additional valve ( 32 ) is arranged according to claim 1 or 2 and arranged for supplying gas to the second fluid line ( 25 ) depending on its valve position. Fluid system according to one of Claims 5 to 8, in which the fluid inlet ( 22a ) of the fluid pump ( 22 ) is hydraulically and / or pneumatically coupled with a fluid filter ( 27 ).