EP2450558A1

EP2450558A1 - Injection valve

Info

Publication number: EP2450558A1
Application number: EP10189756A
Authority: EP
Inventors: Valerio Polidori
Original assignee: Continental Automotive Technologies GmbH
Current assignee: Aumovio Germany GmbH
Priority date: 2010-11-03
Filing date: 2010-11-03
Publication date: 2012-05-09

Abstract

The invention is related to an injection valve comprising a hollow fluid inlet portion (1) with a check valve (2), wherein the check valve (2) comprises a support means (3) and a ball (4) .

Description

The invention relates to an injection valve comprising a hollow fuel inlet portion.
Fuel inlet portions of an injection valve are used for receiving fuel from a fuel support means like a fuel rail and/or a manifold and for feeding received fuel to an injection nozzle at a front end of the injection valve. Such a fuel inlet portion may also comprise an inlet fitting and/or an inlet filter for filtering the fuel. With modern direct injection systems for internal combustion engines fuel is under high pressure, for example at 200 bar or higher in case of gasoline engines and at 2000 bar or even higher in case of diesel engines.
Whenever the fuel support means has to be disconnected from an injection valve (this may occur due to maintenance purposes or for exchanging an injection valve) there is a danger that a backflow of liquid or vaporized fuel may occur, and this backflow may be hot due to the temperature of the engine, to which the injection valve is mounted. In any case this spray of fuel flowing back is dangerous for the health of the people working at this injection valve due to the fact, that fuel generally is toxic and may be hot.
It is an object of the invention to create an injection valve, with which said danger of backflow is eliminated. This object is solved by the features of independent claim 1. Advantageous embodiments of the invention are given in depending claims.
The invention is disclosed in more details herein after by means of a drawing. The figures are as follows:

Fig. 1:: a traditional injection valve mounted onto the cylinder head of an internal combustion engine,
Fig. 2:: an enlarged view of a section of the injection valve according to a first embodiment of the invention,
Fig. 3:: a detail of Fig. 2,
Fig. 4,: 5: a demonstration of the function of the first embodiment,
Fig. 6:: an enlarged view of a section of the injection valve according to a second embodiment of the invention,
Fig. 7:: a detail of Fig. 6, and
Fig. 8, 9:: a demonstration of the function of the second embodiment.

Fig. 1 shows a traditional injection valve V mounted into the cylinder head H of an internal combustion engine. It also shows the spray S of backflow of fuel as described herein before, and the region, where a hollow fluid inlet portion 1 is arranged within the injection valve, intended to be connected to a manifold and/or a common rail.
Fig. 2 shows a section of an injection valve according to a first embodiment of the present invention. Moreover, it shows a hollow fluid inlet portion 1 (including an inlet fitting 1ʹ in this example) comprising a check valve 2. According to the present invention, the check valve 2 comprises a support means 3 and a ball 4. This check valve 2 will prevent said toxic and hot backflow, whenever the injection valve will, at its hollow fluid inlet portion 1, be disconnected from a manifold and/or from a common rail.
Due to the fact that fuel is often very aggressive, especially when being hot, it is advantageous, if the support means 3 and/or the ball 4 are made of materials being resistant against corrosion. Such material may be metallic material like stainless steel or it may be plastic material of a given hardness.
Fig. 3 shows the check valve 2 of Fig. 2 in more detail. The support means 3 of this check valve 2 is made in the form of a tripod having, for example, three legs 3a and an end part 3b, where the legs 3a join each other. It is advantageous, if the end part 3b comprises a recess where the ball 4 may rest during regular operation of the injector valve, i. e., when no back flow of fuel is to be expected.
Fig. 4 and 5 show an enlarged view of the section of the hollow inlet portion 1 with the check valve 2 in operation: Fig. 4 shows a situation, where the injection valve is in regular operation and Fig. 5 shows a situation, where above described back flow is likely to occur, but is prevented by the check valve.
Fig. 4 shows a first part 1a of the hollow inlet portion 1 and a second part 1b of the hollow inlet portion 1. The first part 1a has a first inner diameter d1 and the second part 1b has a second inner diameter d2. Both inner diameters d1, d2 are different from each other and the second inner diameter d2 is larger than the first inner diameter d1. Additionally, the first inner diameter d1 is smaller than a diameter d4 (see Fig. 3) of the ball 4, and the second inner diameter d2 is larger than the diameter d4 of the ball 4. Accordingly, the ball 4 may move up and down within the second part 1b, but not within the first part 1a.
In a case, where it is assumed, that the injection valve is mounted to a cylinder head of an internal combustion engine and, at an outer end of the hollow fluid inlet portion 1, to a manifold (may be, a manifold of a fuel supply system like a common rail system) and where the engine is running, fuel flows from the manifold (not shown) into the injection valve, namely into and through the hollow fluid inlet portion 1, there passing the first part 1a thereof and then the second part 1b thereof (the direction of the fuel is shown by arrows). Due to the force of the flowing fuel the ball 4 is pressed towards the tripod and rests in a resting position on the tripod, especially on the recess, with which the upper end of the tripod is provided, whereas the fuel flows along the surface of the ball 4 in direction to the tripod. There the fuel passes the tripod between its legs, and from there the fluid flows, just as usual, towards a nozzle at the front end of the injection valve.
In a case, however (and this situation is demonstrated in Fig. 5), in which the injection valve is disconnected from above mentioned manifold, the fuel inside the injection valve tries to flow back into the direction of the first part 1a of the hollow fluid inlet portion 1, because the fuel is under pressure and because it wants to expand for reducing this pressure. Accordingly, the ball 4 is picked up by the fuel and pressed against the adjacent end of the first part 1a, which is designed to act as a sealing seat in such a situation. As a consequence, fuel cannot exit the injection valve via the hollow fuel inlet portion 1.
Fig. 6 shows a section of an injection valve according to a second embodiment of the present invention. Moreover, it shows a hollow fluid inlet portion 1 (including an inlet fitting 1' in this example) comprising a check valve 2. According to the present invention, the check valve 2 comprises a support means 3 and a ball 4. Also this check valve 2 will prevent said toxic and hot backflow, whenever the injection valve will, at its hollow fluid inlet portion 1, be disconnected from a manifold and/or from a common rail.
Fig. 7 shows the check valve (2) of Fig. 6 in more detail. The support means (3) of this check valve (2) is made in the form of a bushing. An upper end part 3b of the bushing is designed so that the ball 4 may rest on it during regular operation of the injector valve, i. e., when no back flow of fuel is to be expected.
Fig. 8 and 9 show an enlarged view of the section of the hollow inlet portion 1 of the injection valve according to the second embodiment of the invention, with the check valve 2 in operation: Fig. 8 shows a situation, where the injection valve is in regular operation and Fig. 9 shows a situation, where above described back flow is likely to occur, but is prevented by the check valve.
Fig. 8 shows a first part 1a of the hollow inlet portion 1 and a second part 1b of the hollow inlet portion 1. The first part 1a has a first inner diameter d1 and the second part 1b has a second inner diameter d2, which may vary within the second part 1b. But in any case both inner diameters d1, d2 are different from each other, and in any case the second inner diameter d2 is larger than the first inner diameter d1. Additionally, the first inner diameter d1 is smaller than a diameter d4 (see Fig. 7) of the ball 4, and at least a maximum value of the second inner diameter d2 is larger than the diameter d4 of the ball 4. Accordingly, the ball 4 may move up and down within the second part 1b, but not within the first part 1a.
Again, in a case, where it is assumed, that the injection valve is mounted to a cylinder head of an internal combustion engine and, at an outer end of the hollow fluid inlet portion 1, to a manifold (may be, a manifold of a fuel supply system like a common rail system) and where the engine is running, fuel flows from the manifold (not shown) into the injection valve, namely into and through the hollow fluid inlet portion 1, there passing the first part 1a thereof and then the second part 1b thereof (the direction of the fuel is shown by arrows). Due to the force of the flowing fuel the ball 4 is pressed towards the bushing and rests in a resting position on the bushing, whereas the fuel flows along the surface of the ball 4 in direction to the bushing. In this example, the sidewall of the bushing has two apertures. Accordingly, the fuel passes the bushing through these apertures, and then, from the inside of the bushing the fluid flows, just as usual, towards a nozzle at the front end of the injection valve.
In a case, however (and this situation is demonstrated in Fig. 9), in which the injection valve is disconnected from above mentioned manifold, the fuel inside the injection valve tries to flow back into the direction of the first part 1a of the hollow fluid inlet portion 1, because the fuel is under pressure and because it wants to expand for reducing this pressure. Accordingly, the ball 4 is picked up by the fuel and pressed against the inner end of the first part 1a, which is designed to act as a sealing seat in such a situation. As a consequence, fuel cannot exit the injection valve via the hollow fuel inlet portion 1.

Claims

Injection valve comprising
a hollow fluid inlet portion (1) with a check valve (2), wherein the check valve (2) comprises a support means (3) and a ball (4).
Injection valve according to claim 1, wherein the support means (3) and/or the ball (4) are of materials resistant against corrosion.
Injection valve according to claim 2, wherein the support means (3) and/or the ball (4) are made of metallic materials.
Injection valve according to any of the preceding claims, wherein the support means (3) and/or the ball (4) are made of plastic materials.
Injection valve according to any of the preceding claims, wherein a first part (1a) of the hollow fluid inlet portion (1) is provided with a first inner diameter (d1) and wherein a second part (1b) of the hollow fluid inlet portion (1) is provided with a second inner diameter (d2), said diameters (d1, d2) being distinct from each other, and said parts (1a, 1b) being arranged adjacent to each other thereby forming a transition between said parts (1a, 1b), the transition being designed to act as a seal seat for the ball (4).
Injection valve according to any of the preceding claims, wherein said support means (3) is a tripod means designed for keeping the ball (4) in a resting position in a flow direction of fuel.
Injection valve according to any of claims 1 to 5, wherein said support means (3) is a bushing designed for keeping the ball (4) in a resting position in a flow direction of fuel.
Injection valve according to any of the preceding claims, wherein the hollow fuel inlet portion (1) has at least a section having an inner diameter being smaller than a diameter (d4) of the ball (4) for preventing backflow of fuel.