DE102018209130A1 - Fuel storage arrangement and internal combustion engine with such an arrangement - Google Patents

Abstract

The present invention relates to a fuel storage arrangement comprising a first fuel reservoir (91) having a first storage volume, a second fuel reservoir (92) having a second storage volume, the first fuel reservoir (91) being hydraulically connected to the second fuel reservoir (92) second storage volume of the second fuel accumulator (92) is smaller than the first storage volume of the first fuel accumulator (91), a supply port (11) which is arranged on the second fuel accumulator (92), and at least one discharge port (12) which on the second fuel accumulator ( 92) is arranged.

Description

State of the art

The present invention relates to a fuel storage arrangement and an internal combustion engine having a water injection system and a fuel injection system with such a fuel storage arrangement.

Internal combustion engines with water injection systems are known from the prior art in various configurations. By means of a water injection, exhaust gas temperatures can be reduced and a tendency to knock during operation can be reduced. Usually known are separate water injection systems, which allow a water injection, such as the DE 10 2015 208 476 A1 , Furthermore, from the DE 10 2014 205 179 A1 an internal combustion engine with water injection system, in which a fuel rail in an additional body is arranged with a groove, wherein the groove connects two fuel outlets to fuel injectors together.

Disclosure of the invention

The fuel storage arrangement according to the invention with the features of claim 1 has the advantage over that a particularly simple and inexpensive to be realized water injection is possible. Water is injected via the existing fuel injectors of an internal combustion engine together with fuel in the form of a fuel-water emulsion as needed. In this case, according to the invention, a particularly short reaction time between a decision that water should additionally be injected into the combustion chamber and the implementation of the additional water injection can be achieved. Nevertheless, a construction effort for the fuel storage arrangement and the water injection system can be minimal and therefore very cost-effective. This is inventively achieved in that the fuel storage arrangement has a first fuel reservoir with a first storage volume and a second fuel storage with a second storage volume. The two fuel storage are hydraulically connected to each other via at least one connecting line. Furthermore, the second storage volume is smaller than the first storage volume. A supply port is also disposed on the second fuel reservoir and a discharge port is also disposed on the second fuel reservoir. The discharge port is in this case connected to a fuel injector, which can inject fuel directly into a combustion chamber or into a suction region of an internal combustion engine. On the one hand only fuel and on the other hand, a fuel-water emulsion are supplied via the supply port, if water is to be injected in addition to the fuel during operation of an internal combustion engine.

The dependent claims show preferred developments of the invention.

Preferably, the first storage volume is by a factor 5 to 15 , preferably by the factor 10 , greater than the second storage volume. Thus, the first storage volume is significantly larger than the second storage volume, wherein the larger storage volume provides for damping in the fuel system.

Since both the supply port and the discharge port is arranged at the smaller second storage volume, the freshly supplied fuel and at a water entry the fuel-water emulsion is fed into the smaller second storage volume and discharged in the shortest possible time via the discharge port from the second storage volume. Thus, even with a longer operation with water injection can be avoided that accumulate large amounts of water in the first larger storage volume. Thus, the supply and discharge at the fuel storage is separated from the actual damping function of the fuel storage. Upon completion of the additional water injection, the fuel-water mixture from the small second storage volume is quickly purged of fuel.

Preferably, the supply port is arranged radially on the second fuel reservoir. In this case, the supply port is particularly preferably arranged centrally on the second fuel reservoir, which preferably has an elongated, tubular shape.

More preferably, the at least one discharge port is also arranged radially on the second fuel storage. Preferably, a discharge port is provided for each cylinder of an internal combustion engine to ensure a supply of fuel. In the case of a plurality of discharge ports, these are preferably arranged symmetrically and adjacent to one another at equal intervals.

According to a further preferred embodiment of the invention, the first fuel reservoir and the second fuel reservoir are elongated components, in particular tubular elongated components, which are arranged parallel and adjacent to each other. As a result, a compact and inexpensive construction can be realized.

The connection between the first and second fuel storage is preferably via a first connecting line and a second connecting line. Preferably, the two connecting lines are arranged as far away from each other at the fuel reservoirs, which has a positive effect on the damping properties within the fuel system. Particularly preferably, the first connecting line are arranged at the first end of the first and second fuel reservoir and the second connecting line is arranged at the second end of the first and second fuel reservoir.

According to an alternative embodiment of the invention, the first and second fuel storage are arranged in a common housing. The common housing are preferably a cast component and the first and second fuel reservoirs are preferably cylindrical recesses in the cast component. As a result, the fuel storage arrangement according to the invention can be produced particularly cost-effectively as a mass component. The first and second fuel storage may then be generated, for example, by machining or lasers or the like.

According to a further preferred embodiment of the invention, a throttle device is arranged in the hydraulic connection between the first and second fuel storage. The throttle device allows the best possible hydraulic separation, to prevent a fuel-water emulsion comes in too large amount in the first storage volume and also can be damped by the throttle device vibrations before reaching the first storage volume.

More preferably, the fuel storage arrangement comprises at least one injector, which is arranged at the discharge port. The injector is preferably arranged directly at the discharge port and is further preferably set up for a direct injection of fuel into a combustion chamber of an internal combustion engine.

Furthermore, the present invention relates to an internal combustion engine having a water injection system and a fuel injection system comprising a fuel storage arrangement according to the invention. The water injection system is connected to the fuel injection system in such a way that, if required, water can be supplied to the fuel injection system and then a fuel-water emulsion can be injected via the already existing fuel injector. Thus, the fuel injector on the one hand only inject fuel and on the other hand inject a fuel-water emulsion. Preferably, the water is supplied as needed into the fuel injection system at a position which is outside of the fuel storage arrangement. As a result, the fuel storage arrangement can be supplied with a fuel-water emulsion which is already well mixed, so that the risk of injection of incorrect fuel-water ratios, in particular the risk of pure water injection or injection with an excessively high water content, is avoided become.

More preferably, the fuel injection system comprises a fuel pump, in particular a high-pressure fuel pump, and the water injection system is connected to the fuel injection system at the fuel pump. In this case, a shut-off valve is preferably arranged in the water injection device in a water line leading to the fuel pump. When the shut-off valve is open, the fuel pump can suck in addition to fuel and water injection system and thus bring to a corresponding pressure level for injection. At the same time there is a very good mixing between water and fuel to achieve the most homogeneous fuel-water emulsion. When the shut-off valve is closed, the fuel pump sucks no water, so that only fuel is supplied to the fuel storage arrangement and accordingly only fuel is injected into the internal combustion engine.

The shut-off valve is preferably actuated by means of a control unit, the control unit being designed to supply water to the fuel injection system as required, for example in the event of the risk of knocking or the desire to reduce the exhaust gas temperatures.

Thus, by the idea according to the invention, on the one hand, only fuel can be injected or, if necessary, water can be added to the fuel and, in shortest time, a fuel-water emulsion can be injected or terminated again.

list of figures

• 1 eine schematische Ansicht einer Brennkraftmaschine mit einer Kraftstoffspeicheranordnung gemäß einem ersten Ausführungsbeispiel der Erfindung,
• 2 eine schematische Ansicht der Kraftstoffspeicheranordnung von 1, und
• 3 eine schematische Ansicht einer Kraftstoffspeicheranordnung gemäß einem zweiten Ausführungsbeispiel der Erfindung.

Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. The same or functionally identical parts are denoted by the same reference numerals. In the drawing is:

• 1 a schematic view of an internal combustion engine with a fuel storage arrangement according to a first embodiment of the invention,
• 2 a schematic view of the fuel storage arrangement of 1 , and
• 3 a schematic view of a fuel storage arrangement according to a second embodiment of the invention.

Preferred embodiments of the invention

The following is with reference to the 1 and 2 an internal combustion engine 1 with a fuel storage arrangement according to the invention 9 according to a first embodiment of the invention described in detail.

The internal combustion engine 1 This embodiment is an Otto internal combustion engine with a water injection system 2 and a fuel injection system 3 , The fuel injection system 3 can be a direct injection system, ie fuel is directly in a combustion chamber 10 the internal combustion engine injected or alternatively, the fuel injection system 3 be a suction injection system in which fuel is injected into a suction region of the internal combustion engine.

The fuel injection system 3 includes a fuel tank 30 , a high-pressure fuel pump 31 , a low-pressure fuel pump 35 and a fuel line 33 which the fuel tank 30 with the fuel storage arrangement 9 combines.

How out 1 can be seen, includes the fuel storage arrangement 9 a first fuel storage 91 and a second fuel storage 92 , The fuel storage arrangement 9 is in detail 2 seen. Here, the first fuel tank 91 a first storage volume which is by the factor 10 is greater than a second storage volume of the second fuel storage 92 , How out 2 is apparent, is a hydraulic connection between the first fuel tank 91 and the second fuel storage 92 via a first hydraulic connection line 93 and a second hydraulic connection line 94 realized. The two connecting lines 93 . 94 are at the two ends of the tubular first and second fuel storage 91 . 92 arranged. It should be noted that on the first connection line 93 can also be dispensed with, so that no fuel-water emulsion in the first fuel tank 91 arrives. More preferably, the first fuel storage 91 also on the side of the second fuel tank 92 to be ordered.

The connection of the components of the fuel storage arrangement 9 In this case, for example, by soldering or welding or the like. Run.

How farther 2 can be seen, are the first and second fuel storage 91 . 92 arranged parallel to each other. The first and second connection line 93 . 94 is designed as short as possible, so that the first and second fuel storage can be arranged immediately adjacent to each other. As a result, a space can be kept small.

At the second fuel storage 92 is still a supply port 11 for supplying fuel and four drain ports 12 for discharging fuel to the fuel injectors 32 arranged. Here, the number of drain connections corresponds 12 the number of cylinders of the internal combustion engine. It should be noted, however, that per drain connection, several cylinders could also be supplied with fuel.

Next, the reference numeral 13 a pressure sensor to a pressure in the fuel storage arrangement 9 determine and optionally the high pressure fuel pump 31 to operate to set a desired pressure level.

We out 1 It can be seen, the high-pressure fuel pump 31 over a camshaft 6 be pressed and fuel in a line section 33a the fuel line between the high pressure fuel pump 31 and the fuel storage arrangement 9 contribute. Optionally, the high pressure fuel pump 31 However, also be operated independently of the camshaft.

Furthermore, the internal combustion engine comprises 1 a water injection system 2 with a water tank 20 and a water pump 21 , A water pipe 23 connects the water tank 20 with the high pressure fuel pump 31 , In the water pipe 23 is also a metering valve 4 arranged. The metering valve 4 is by means of a control unit 5 actuated.

How out 1 it can be seen, is the metering valve 4 a 2/2-way valve and has two positions, namely an open position and a closed position. In 1 Here, the closed position is shown.

The internal combustion engine 1 This embodiment is a direct-injection internal combustion engine, wherein the fuel injectors 32 directly on the combustion chamber 10 are arranged. Schematically are in 1 a suction area 8th and an inlet valve 7 indicated the internal combustion engine.

The internal combustion engine 1 with the fuel storage arrangement according to the invention 9 can now be operated in different operating modes. In normal operating mode, only one takes place Injection of fuel, without additional water would be injected into the combustion chamber. This operating mode is in 1 shown. The fuel injectors 32 inject pure fuel into the combustion chambers 10 on.

How out 2 becomes clear, the fuel supplied through the fuel lines 33 and 33a to the supply connection 11 at the second fuel storage 92 fed. Here, the fuel in the second fuel tank 92 distributed with a small storage volume and via the drain connections 12 to the fuel injectors 32 supplied for injection.

For the operating mode, in which in addition to the fuel still water in the combustion chamber 10 is to be injected, opens the controller 5 the metering valve 4 so that the high pressure fuel pump 31 In addition to the fuel additionally water from the water pipe 23 sucks. Thus, the line section becomes 33a supplied to the fuel line, a fuel-water mixture in the form of an emulsion. This fuel-water emulsion is then added to the second fuel reservoir 92 supplied with a small storage volume. From the second fuel storage 92 The fuel-water emulsion is then delivered via the force injectors 32 in the combustion chambers 10 injected.

As the storage volume of the second fuel storage 92 is very small and the fuel-water emulsion is constantly injected during operation of the internal combustion engine, the newly supplied mixture is always injected directly into the combustion chamber. This will prevent the fuel-water mixture in the first fuel tank 91 arrives. Theoretically, here is the possibility that the fuel-water mixture through the first and second connecting line 93 . 94 in the first fuel storage 91 However, this is in the first fuel tank 91 supplied amount of water very low.

If in the first and second connection line 93 . 94 preferably additionally throttle means are arranged to the first fuel storage 91 from the second fuel storage 92 To decouple is the risk of water entering the first fuel tank 91 further reduced.

Thus, it can be ensured that in operation as possible a small amount of water in the first fuel tank 91 is present, so that when stopping the engine and at temperatures below a freezing point of water, the risk of freezing water in the first fuel tank 91 is reduced.

Furthermore, when the internal combustion engine is switched off, the water injection system is also used 2 emptied of water by, for example, the water from the water pipe 23 by reversing a conveying direction of the water pump 21 back to the water tank 20 is pumped.

It should be noted that for the fastest possible reaction to a water requirement of the internal combustion engine, the volume of the line section 33a the fuel line is chosen as small as possible. As the volume of the second fuel tank 92 is very small, this can be a rapid implementation of a desire for water injection in addition to the fuel injection allows.

3 shows an energy storage arrangement 9 according to a second embodiment of the invention. How out 3 can be seen, the fuel storage arrangement 9 a common housing 90 in the form of a cast housing. Here are the first fuel storage 91 and the second fuel storage 92 as a separate storage volume in the common housing 90 arranged. Not shown first and second connecting lines are the storage volumes of the first and second fuel storage 91 . 92 connected with each other. The housing 90 has an oval-shaped cross-section. The first and second fuel storage 91 . 92 are arranged parallel to each other and one above the other with the smallest possible distance. By cast manufacturing, this can be a particularly cost-effective production of the fuel storage arrangement 9 with two fuel tanks 91 . 92 to be obtained. The two fuel tanks 91 . 92 For example, they can be produced in the form of blind bores by means of machining processes, in particular drilling or by means of lasers. The open side of the fuel storage 91 . 92 can then be welded for example by means of lids. The drain connections 12 as well as the inlet connection 11 , which in each case with the second fuel storage 92 can also be made by drilling or laser machining.

Thus, according to the invention an internal combustion engine can be provided with water injection, in which a very short response time for the water injection is possible and still a sufficiently large storage volume in a fuel storage arrangement 9 is present to dampen vibrations and the like. Thus, a very short period of time is possible, in which the water injection can be activated and in the form of a fuel-water emulsion in a combustion chamber 10 can be injected. The fuel storage arrangement described in the embodiments 9 is especially usable in direct injection internal combustion engines.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015208476 A1 [0002]
• DE 102014205179 A1 [0002]

Claims (12)

Fuel storage arrangement comprising: a first fuel reservoir (91) having a first storage volume, a second fuel reservoir (92) having a second storage volume, wherein the first fuel reservoir (91) is hydraulically connected to the second fuel reservoir (92), - wherein the second storage volume of the second fuel reservoir (92) is smaller than the first storage volume of the first fuel reservoir (91), - A supply port (11) which is disposed on the second fuel reservoir (92), and - At least one discharge port (12) which is arranged on the second fuel reservoir (92). Fuel storage arrangement according to Claim 1 wherein the first storage volume of the first fuel reservoir (91) is 5 to 15 times, in particular 10 times, larger than the second storage volume of the second fuel reservoir (92). Fuel storage arrangement according to one of the preceding claims, wherein the supply port (11) is arranged radially on the second fuel reservoir (92). Fuel storage arrangement according to one of the preceding claims, wherein the discharge port (12) is arranged radially on the second fuel reservoir (92). A fuel storage assembly according to any one of the preceding claims, wherein the first fuel reservoir (91) and the second fuel reservoir (92) are elongated members and disposed parallel to one another. A fuel storage assembly according to any one of the preceding claims, wherein a connection between the first and second fuel reservoirs (91, 92) comprises a first connection line (93) and a second connection line (94). Fuel storage arrangement according to one of the preceding claims, wherein the first fuel accumulator (91) and the second fuel accumulator (92) in a common housing (90), in particular a cast housing, are arranged. Fuel storage arrangement according to one of the preceding claims, further comprising at least one fuel injector (32), which is arranged directly on the second fuel reservoir (92). An internal combustion engine comprising a water injection system (2) and a fuel injection system (3), the water injection system (2) being connected to the fuel injection system (3), and wherein the fuel injection system (3) comprises a fuel storage arrangement (9) according to one of the preceding claims. Internal combustion engine after Claim 9 wherein the water injection system (2) is connected to the fuel injection system (3) at a position outside the fuel storage assembly (9). Internal combustion engine after Claim 10 wherein the water injection system (2) is connected to a fuel pump (31) of the fuel injection system (3). Internal combustion engine according to one of Claims 10 to 11 wherein the water injection system (2) comprises a metering valve (4) in a water line (23), the metering valve (4) being arranged to connect to the fuel injection system (3) or to disconnect from the fuel injection system (3).

Images