Patent Application
20100006060
The invention relates to a high pressure injection arrangement for an internal combustion engine with direct injection with an injection valve and a support element, which supports the injection valve in the installed state on a seat of an internal combustion engine.
High pressure injection arrangements of internal combustion engines with direct injection, which have injection valves based on solenoid valve technology, develop high momenta during operation by the solenoid striking its end stops when the valve opens and closes, momenta that are transferred via the housing of the injection valve and the support element to the internal combustion engine and thus result in a noise emission that is perceptible by humans. In particular by reflection of free, oscillating surfaces in or on the cylinder head of the internal combustion engine, thus excited sound pulses that are very readily perceptible by humans are emitted. Because of the high opening and closing frequency of such injection valves, this sound frequency is in a relatively high frequency range that is considered to be very unpleasant to the human ear. Moreover, a clarion, mechanical striking noise, a “ticking,” is perceptible. To minimize this undesirable sound pulse, it is known to provide elastic arrangements in the area in which the injection valve is supported on the cylinder head. For example, an arrangement in which a support element, namely a seat ring, supports the injection valve in the cylinder head is known from EP 1 134 406 B1. In the arrangement that is described there, it is disadvantageous that the seat ring and the spring element are spaced far apart from one another and that the bow-shaped spring element is suspended in a ring around the housing, i.e., ultimately provides no effective momentum damping but rather serves primarily as a fastening device. The latter, in particular in the radial respect, claims considerable installation space and requires a design of the spring element in the area of an electric connection and/or the connection of a fuel line in the end area of the injection valve. In particular, in this connection, the actual momentum transfer via the seat ring to the cylinder head is not effectively suppressed.
The object of the invention is to provide a high pressure injection arrangement that avoids the above-mentioned drawbacks and offers as complete elimination as possible of mechanical momentum input that leads to undesirable acoustic phenomena, due in particular to solid-borne sound conduction or excitation of oscillating surfaces in the engine block, in particular the cylinder head of the internal combustion engine.
In this way, a high pressure injection arrangement for an internal combustion engine with direct injection is proposed with an injection valve and a support element that supports the injection valve in the installed state on a seat of an internal combustion engine. In this connection, it is provided that a spring element is arranged between the injection valve and the support element. In this connection, the injection valve is held in a support element that supports the injection valve in its installed state on the seat of the internal combustion engine that is intended for it. A spring element is arranged between the injection valve and the support element. Accordingly, unlike in the prior art, the momentum that is produced by the solenoid valve of the injection valve is not transferred from the housing of the injection valve directly to the support element, as a result of which the damping or even the extinction of the momentum can take place only to the extent allowed by the material and design of the support element, but rather the momentum is first transferred to a spring element that is arranged between the support element and the injection valve and from the latter to the support element. In this way, a considerable portion of the momentum in the spring element is already consumed. The support element is therefore only affected by momentum to a far lesser extent than in the prior art, so that its share of the residual momentum to be damped is relatively small.
The spring element is preferably a spring washer. In this connection, the spring element is designed essentially flat, specifically, as a spring washer, here a spring washer being also defined as a lock washer, i.e., a spring washer with an essentially central opening.
It is further provided in one embodiment that the spring washer has an inside ring zone and an outside ring zone, with the inside ring zone resting on the injection valve in a first contact area and the outside ring zone resting on the support element in a second contact area. The first contact area is consequently the contact area in which the injection valve is in close contact with the inside ring zone of the spring washer, while the second contact area is the one in which the outside ring zone contacts the support element. The spring washer is consequently designed as a ring, namely as a lock washer, which is centrally penetrated by the injection valve, which is made, for example, stepped. In this connection, the inside ring zone rests on the injection valve and thus forms the first contact area. The outside ring zone rests on the support element and thereby mediates the support of the injection valve via the spring washer on the support element in the second contact area. It is essential in this connection that the injection valve not rest directly on the support element and preferably also in such a way that the first contact area and the second contact area, viewed in axial extension of the injection valve, are not aligned. In this way, solid-borne sound transfer or momentum input by the injection valve into the cylinder block, namely via the support element, is very effectively prevented.
The first contact area is preferably a first line contact area. By means of the line contact area, an essentially pure line-shaped contact formation can be achieved, so that a large-area contact is avoided, and a geometrically exactly defined momentum input into the spring washer takes place via the spatially very concentrated local pressure that develops in this connection when the momentum strikes the line contact area.
The second contact area is especially preferably a second line contact area. In this connection, what is stated for the first line contact area applies accordingly.
In another, especially preferred design, the first contact area is at a radial distance from the second contact area. In this respect, a kind of lever by which the injection valve is kept elastic/suspended relative to the injection valve, i.e., can spring in and out in particular in the axial direction, is formed between the first contact area and the second contact area, in particular namely the first line contact area and the second line contact area. In this way, direct momentum input by the injection valve onto the support element and via the latter into the cylinder head is avoided. By this arrangement, a spring-mass system is also formed, by which any momentum can be degraded as a damped oscillation.
In one embodiment, the spring element consists of steel. In particular, the use of commonly used spring steel or else ordinary steel, for example a washer, is considered. For this application, steel has very good elasticity and strength values.
It is preferably provided that the support element consists of plastic. In this way, self-damping of the support element can be produced, namely by the selection of the plastic material, as a result of which the residual momentum that is still introduced into the support element can be advantageously damped, so that the latter is not introduced into the cylinder head (or only to a very small extent). The embodiment of a plastic support element without the spring element according to the invention would be conceivable in principle, but in this connection the support element would have to be designed especially large to achieve an only approximately similarly good damping value, which could produce, on the one hand, installation space problems, and, on the other hand, accuracy problems, in particular in the assembly and in the achievable seat of the internal combustion engine; such a support element, taken by itself, would not be able to achieve the proposed high momentum damping.
In another embodiment, the support element is a cage element. Thus, it is meant that the support element encompasses the injection valve at least in certain areas. In particular, it is provided to design the cage element such that the support element has a seat ring that locks in support element holding devices of the injection valve, for example, with clips or clip arms that are extended on the cage element on the outside in the axial direction of the injection valve. Thus, a very simple and reliable mounting of the support element on the injection valve can be achieved; in particular, the injection valve can be preassembled with the support element and the spring washer or the spring element stored therein and is thus available as a subassembly for installation in the internal combustion engine.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 032 385.3 | Jul 2008 | DE | national |
