DE102014224345A1 - Direct injection gas injector with elastomeric sealing seat and at least two sealing edges - Google Patents

Abstract

The invention relates to a gas injector for injecting a gaseous fuel directly into a combustion chamber of an internal combustion engine, comprising a valve closing element (2) for releasing and closing a passage opening, a first sealing seat (3) with two metallic sealing partners (31, 32), a second sealing seat ( 4) with an elastomer sealing partner and a first sealing edge (11), and a third sealing seat (5) with an elastomer sealing partner and a second sealing edge (12).

Description

State of the art

The present invention relates to a direct-injection gas injector with an elastomer sealing seat and at least two sealing edges which seal at the elastomer sealing seat.

In addition to liquid fuels, gaseous fuels, such as e.g. Natural gas or hydrogen, used. In Direktinblasenden Gasinjektoren is a problem area the seal with a closed gas injector. A suitable sealing material on the sealing seat would in this case be, for example, an elastomer, which, however, has hitherto not been used because of its limited temperature resistance and a high susceptibility to wear for direct-injection gas injectors. In addition to the good sealing properties of the elastomer while its excellent damping properties during the closing process are advantageous.

Disclosure of the invention

The direct injection gas injector according to the invention for injecting a gaseous fuel directly into a combustion chamber of an internal combustion engine with the features of claim 1 has the advantage that an elastomer can be used as a sealing element on at least one sealing seat. Thus, the gas injector according to the invention also in the non-actuated, closed state on a sufficient tightness. According to the invention, a first sealing seat with two metallic sealing partners, a second sealing seat with an elastomeric sealing partner and a first sealing edge and a third sealing seat with an elastomeric sealing partner and a second sealing edge are provided. Thus, according to the invention at least three sealing seats are provided, so that a sufficient tightness in the closed state can be achieved.

The dependent claims show preferred developments of the invention.

Preferably, the elastomeric sealing partner at the first and second sealing seat is a common first elastomeric element. As a result, the assembly can be simplified and the number of components can be reduced.

More preferably, the direct-injection gas injector comprises a fourth sealing seat with an elastomeric sealing partner and a third sealing edge. Like the second and third sealing seat, the fourth sealing seat can likewise be provided on a common elastomer element or, alternatively, can also be provided on a separate second elastomer element.

More preferably, the valve closing element has a first annular flange, on which the first sealing seat is provided. The annular flange is preferably provided disc-shaped on a cylindrical main body of the valve closing element. The first annular flange additionally serves as a shielding element against hot gases of the combustion chamber.

According to a further preferred embodiment of the invention, the valve closing element further comprises a second annular flange. At the second annular flange of the elastomeric sealing partner is arranged.

Particularly preferably, the first metallic sealing seat is provided as a stop and the second and third sealing seat, which have the elastomeric sealing partner, provided as a damping sealing seat during the closing operation.

Preferably, the second annular flange has at least one first passage opening. As a result, fuel can be passed through the first through-opening on the second annular flange, so that a fuel path through the gas injector can be relatively straight.

More preferably, the first and second sealing edge are provided on a valve body. The sealing edges are preferably arranged on a radially inwardly directed flange region of the valve body.

Preferably, a second passage opening is provided between the first and second sealing edge. This makes it possible that the second passage opening is kidney-shaped. Preferably, a plurality of second passage openings are provided along the circumference.

More preferably, the second and third sealing seat are arranged in the flow direction of the gas injector in front of the first sealing seat. That is, the first sealing seat is closer to the combustion chamber than the second and third sealing seats. Since the first sealing seat is a metallic sealing seat, it can be exposed to the high temperatures in the combustion chamber without damaging the metallic first sealing seat. At the same time, the first sealing seat protects the second and third sealing seats comprising elastomeric elements.

According to a further preferred embodiment of the present invention, the valve closing element comprises a lock cylinder with flow openings. The lock cylinder is here preferably arranged on a valve needle of the valve closing element. In this case, the first, second and third sealing seat is provided on the lock cylinder. By using the lock cylinder, a particularly compact design can be realized. Furthermore, no kidney-shaped openings are necessary, which are relatively expensive to produce, but the flow openings can be provided in the lock cylinder. The flow openings are particularly preferably in the axial direction extending slots. These can be produced in a particularly simple and cost-effective manner.

Particularly preferably, the valve closing element is an outwardly opening valve closing element.

Furthermore, the present invention relates to an internal combustion engine comprising a combustion chamber and a gas injector according to the invention, wherein the gas injector is arranged directly on the combustion chamber to inject gaseous fuel directly into the combustion chamber.

drawing

Hereinafter, several embodiments of a gas injector according to the invention with reference to the figures will be described in detail. In the drawing is:

1 a schematic sectional view of a gas injector according to a first embodiment of the invention in the closed state,

2 a schematic sectional view taken along the line II-II of 1 .

3 a schematic sectional view of the gas injector of 1 in the open state,

4 a schematic sectional view of a gas injector according to a second embodiment of the invention,

5 a schematic sectional view of a gas injector according to a third embodiment of the invention, and

6 a schematic, perspective view of the gas injector of 5 ,

Preferred embodiments of the invention

The following is with reference to the 1 to 3 a gas injector 1 according to a first preferred embodiment of the invention described in detail.

How out 1 can be seen, includes the gas injector 1 a valve closing element 2 which is a valve needle with a cylindrical main body in this embodiment. XX indicates the axial direction of the gas injector. The valve closing element 2 gives it a passage opening 10 to a combustion chamber 16 free or closes these. 1 shows the closed state of the gas injector. The gas injector 1 is an outwardly opening gas injector, as in 1 indicated by the arrow A.

The gas injector 1 further comprises a plurality of sealing seats, which between the valve closing element 2 and a valve body 8th are provided. More specifically, the gas injector includes 1 a first sealing seat 3 , which with two metallic sealing partners 31 . 32 is realized. A first metallic sealing partner 31 is on a first ring flange 21 the valve closing element 2 provided and a second metallic sealing partner 32 is on the valve body 8th intended. The first metallic sealing seat 3 is designed as a flat seat.

Furthermore, the gas injector includes 1 a second sealing seat 4 , a third sealing seat 5 and a fourth sealing seat 6 , The second sealing seat 4 is between a first elastomeric element 7 and a first sealing edge 11 educated. The third sealing seat 5 is between the elastomer element 7 and a second sealing edge 12 educated. The fourth sealing seat 6 is between a second elastomeric element 70 and a third sealing edge 13 educated. The three sealing edges 11 . 12 . 13 are doing on a radially inwardly directed Ventilkörperflansch 80 intended. The first elastomer element 7 and the second elastomeric element 70 are on a second annular flange 22 , which radially on the valve closing element 2 is provided directed to the outside, arranged. To a movement of the valve closing element 2 ensuring there is a small gap 40 between the valve body flange 8th and the valve closing element 2 intended.

In the valve body flange 80 is still a second through hole 9 educated. How out 1 can be seen, seal the first sealing edge 11 and the second sealing edge 12 each side of the second passage opening 9 from. How out 2 can be seen has the second passage opening 9 a kidney-shaped form on and in the circumferential direction are four second through holes 9 intended. The second sealing seat 4 seals radially outside the second passage openings 9 off and the third sealing seat 5 seals radially inside the through holes 9 from. The fourth sealing seat 6 seals at the second elastomeric element 70 radially outside the gap 40 from. The sealing seats 4 . 5 . 6 are each annularly provided (see. 2 ).

When a blowing process of a gaseous fuel into the combustion chamber 16 is to be made, actuates a not shown actuator, such as a solenoid actuator or a piezoelectric actuator, the valve closing element 2 in the direction of arrow A ( 1 ). This will be the gas injector 1 from the closed state of 1 transferred to the open state, which in 3 is shown. This allows the gaseous fuel, as in 3 indicated by the arrows B and C, through the second passage opening 9 and radially outside the second annular flange 22 and by the first through-hole formed in the second annular flange 23 past the first seal seat 3 stream.

By providing several sealing edges 11 . 12 . 13 can even in tight space conditions inside the gas injector 1 large cross sections are released for the stroke, wherein the cross sections in the interior of the gas injector the released cross section at the first sealing seat 3 equivalent. As a result, a throttle effect is reduced in the interior of the gas injector. The elastomer sealing seats inherently have a smaller seat diameter, as they are inside the injector and not at its end as the first sealing seat 3 lie. In addition, a certain elastic stroke must be covered here until a cross-section opens. For precise quantity control, therefore, should be designed as a steel seat first sealing seat 3 represent the smallest opening cross section. Only the multiple sealing line in the elastomer seat area can do so with a smaller seat diameter. Thus, according to the invention, a necessary flow cross-section can be released everywhere, which, due to the gaseous state of the fuel compared with liquid fuel, must be significantly greater, by the same amount of fuel during a Einblasvorgangs in the combustion chamber 16 contribute.

Furthermore, the first metallic sealing seat protects 3 the further inside, combustion chamber remote elastomeric sealing seats 4 . 5 . 6 in thermal terms. Hot combustion gases come with the gas injector according to the invention 1 not in direct contact with the elastomeric elements 7 . 70 so that damage to the elastomeric elements during operation can be avoided. In this case, an arrangement of the second annular flange 22 on the valve closing element 2 chosen such that in the closed state of the gas injector a sufficient distance H in the axial direction XX to the first annular flange 20 is present to keep the thermal load of the elastomeric elements as small as possible.

The distance H is preferably selected such that the distance H is greater than a maximum stroke length of the valve closing element 2 in the axial direction XX during the opening operation.

4 shows a gas injector 1 according to a second embodiment of the invention. In contrast to the first embodiment, in the second embodiment, the valve body flange 80 at its radially inward side 81 several grooves 82 educated. With open gas injector 1 which is in 4 is shown in the open state, thus gaseous fuel along the grooves 82 between the main body of the valve closing element 2 and the valve body flange 80 stream. This is in 4 indicated by the arrow D. Instead of the grooves 82 Alternatively, several flattened areas can be provided.

In the 5 and 6 is a gas injector 1 provided according to a third embodiment of the invention. In contrast to the preceding embodiments, the gas injector of the third embodiment comprises a valve closing element 2 which is a lock cylinder 50 includes. The lock cylinder 50 is at a needle-like area 52 the valve closing element 2 , eg by welding, fixed. At the lock cylinder 5 is the first sealing seat 3 , the second seal seat 4 and the third sealing seat 5 intended. The fourth sealing seat 6 is between the needle-like area 52 the valve closing element 2 and one with the valve body 8th connected intermediate piece 88 intended. At the intermediate piece 88 is both a first elastomeric element 7 , as well as a second elastomeric element 70 , intended. By providing the lock cylinder 50 on the valve closing element 2 a particularly inexpensive and simple construction can be realized. Otherwise, this embodiment corresponds to the previous embodiments, so that reference can be made to the description given there.

According to the invention thus at least three sealing seats are provided, wherein the combustion chamber next sealing seat preferably as a metallic sealing seat 3 is trained. The two sealing seats further away from the combustion chamber may have at least one elastomeric sealing partner. The two elastomeric sealing partners having sealing seats 4 . 5 are provided adjacent to each other, so that a common elastomer element 7 for both sealing seats 4 . 5 can be used.

Claims (14)

Gas injector for injecting a gaseous fuel directly into a combustion chamber of an internal combustion engine, comprising: - a valve closing element ( 2 ) for releasing and closing a passage opening, - a first sealing seat ( 3 ) with two metallic sealing partners ( 31 . 32 ) A second sealing seat ( 4 ) with an elastomer sealing partner and a first sealing edge ( 11 ), and - a third sealing seat ( 5 ) with an elastomer sealing partner and a second sealing edge ( 12 ). Gas injector according to claim 1, characterized in that the elastomeric sealing partner of the second sealing seat ( 4 ) and the third sealing seat ( 5 ) a common first elastomeric element ( 7 ). Gas injector according to one of the preceding claims, further comprising a fourth sealing seat ( 6 ) with an elastomeric sealing partner and a third sealing edge ( 13 ). Gas injector according to claim 3, characterized in that the elastomeric sealing partner of the fourth sealing seat ( 6 ) a second elastomeric element ( 70 ). Gas injector according to one of the preceding claims, characterized in that the valve closing element ( 2 ) a first annular flange ( 21 ), on which the first sealing seat ( 3 ) is arranged. Gas injector according to one of the preceding claims, characterized in that the valve closing element ( 2 ) a second annular flange ( 22 ), on which the second sealing seat ( 4 ) and the third sealing seat ( 5 ) are arranged. Gas injector according to claim 6, characterized in that the second annular flange ( 22 ) at least one first passage opening ( 23 ) having. Gas injector according to one of the preceding claims, characterized in that the first sealing edge ( 11 ) and the second sealing edge ( 12 ) on a valve body ( 8th ) are provided. Gas injector according to claim 8, characterized in that a second passage opening ( 9 ) between the first sealing edge ( 11 ) and the second sealing edge ( 12 ) is provided. Gas injector according to one of the preceding claims, characterized in that the first sealing edge ( 11 ) and the second sealing edge ( 12 ) on a valve body flange ( 80 ) are provided. Gas injector according to one of claims 6 to 10, characterized in that the first annular flange ( 21 ) closer to the combustion chamber than the second annular flange ( 22 ) is arranged. Gas injector according to one of claims 1 to 5, characterized in that the valve closing element ( 2 ) a lock cylinder ( 50 ) with flow openings ( 51 ), wherein the first sealing seat, the second sealing seat and the third sealing seat on the lock cylinder ( 50 ) are provided. Gas injector according to claim 12, characterized in that the flow openings ( 51 ) are in the axial direction (XX) extending slots. Internal combustion engine, comprising a combustion chamber ( 16 ) as well as a gas injector ( 1 ) according to one of the preceding claims, wherein the gas injector ( 1 ) directly on the combustion chamber ( 16 ) is arranged to supply gaseous fuel directly into the combustion chamber ( 16 ).

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