EP0975869B1 - Fuel injection system for an internal combustion engine with a common rail - Google Patents

Description

The invention relates to a fuel injection system for an internal combustion engine with a common rail according to the preamble of claim 1.

In internal combustion engines, especially large-volume diesel engines Fuel injection systems used which fuel injectors for injecting fuel into the combustion chambers of the internal combustion engine and one by a high-pressure pump with fuel have supplied so-called common rail, the fuel from the latter over High pressure lines are fed to the injectors.

There is a general desire to have internal combustion engines and their fuel injection systems easier to set up and easier to maintain and less prone to malfunction.

A fuel injection system for an internal combustion engine is known from EP 0690 221 A1 Fuel injectors for injecting fuel into the combustion chambers and one through one High-pressure pump with fuel-supplied common rail, of which the Fuel is supplied to the injectors via high pressure lines. Here is the common rail integrated into the wall of a cylinder head cover arranged on the internal combustion engine. It is considered advantageous in the cited document that the manufacturing and Assembly effort reduced and the common rail rail against vibrations and Damage is arranged protected. It seems disadvantageous, however, that disassembly of the Do not remove the cylinder head cover without loosening the one connected to the common rail High pressure lines is possible.

Furthermore, from DE-GM 75 15 413 an internal combustion engine with a Fuel injection system known in which all the channels required for the fuel line in an extruded profile are arranged running parallel, the extruded profile Is part of the engine cowling or the cooling air duct. This is intended to ensure reliable, Space-saving and easily assembled arrangement of the fuel lines can be created. However, here too it appears to be disadvantageous that one is necessary for maintenance work Dismantling the engine cowling or cooling air duct also all connections of the fuel channels the extruded profile must be solved.

An internal combustion engine is known from EP 0637 687 A1, in which fuel is supplied to single injection pumps in the form of plug-in pumps as fuel feed and Fuel return channels in the form of holes in the cylinder housing Internal combustion engine are provided. However, these fuel channels are only used for supply and discharge of the fuel to the plug-in pumps, but it is not a Injection system with a common rail.

Finally, an internal combustion engine is known from US Pat. No. 3,845,748, in which a fuel injector is arranged in a first bore in the cylinder head of the internal combustion engine and one to the Fuel injector leading tube to supply fuel in a second through the Cylinder head leading bore is arranged, which is at right angles to the first bore runs. One between the fuel supply tube and the inner wall of the second bore the remaining annular space serves as fuel return.

The object of the invention is to provide a fuel injection system for an internal combustion engine create that is simple, accident-proof and less prone to failure.

This object is achieved by a fuel injection system with the features of claim 1. The fuel injection system according to the invention is for an internal combustion engine, in particular a diesel engine is provided, the internal combustion engine having a crankcase and one or has several cylinder heads. The fuel injection system has fuel injectors for Injecting fuel into the combustion chambers of the internal combustion engine and one through one High pressure fueled common rail, from which the fuel is supplied via a High pressure line system is supplied to the injectors. According to the invention, it is provided that the common rail is received in a channel that of Walls of the crankcase and a charge air tube is formed.

An advantage of the fuel injection system according to the invention is that recording of the common rail according to the invention, a compact design of the Internal combustion engine is possible. The accommodation in the area of the crankcase disturbs the Contour course of the internal combustion engine little and narrows the tight space in the area Cylinder head not one. In particular, the injection system is also resistant to external damage well protected.

According to a development of the invention, it is provided that the common rail in an integrated in the crankcase parallel to the longitudinal axis of the crankcase Channel arranged or in one of the crankcase walls and a charge air tube Channel is recorded. As a result, a smooth outer contour of the internal combustion engine is without disruptive lines can be realized.

According to another development, the common rail is tubular.

Of particular advantage is an embodiment of the invention in which the tubular common rail rail in a longitudinal bore running parallel to the longitudinal axis of the crankcase is arranged. This enables the common rail rail to be precisely fitted in a simple manner in the radial and axial direction, with the common rail in particular can be stored vibration-proof.

It is particularly advantageous here that the tubular common rail rail z. B. by means of O-rings to be stored in the longitudinal bore. This type of storage is simple, accurate and vibration safe.

It is particularly advantageous to encapsulate the common rail in a liquid-tight manner To arrange the crankcase of the internal combustion engine.

This is advantageously further developed in that the one that houses the common rail rail Channel forms a liquid-tight leakage space, which with means for the discharge of Leakage quantities is provided.

In this embodiment, the leakage space is advantageously provided with a control hole Provide display of leakage quantities.

In combination with the arrangement of the common rail according to the invention, it is from a particular advantage, including those that connect the injectors to the common rail High-pressure lines and the injectors themselves encapsulated in the housing of the internal combustion engine accommodate. This leads to complete protection of the entire injection system against Damage from external influences and enables a completely smooth outer contour of the Internal combustion engine without any lines or protruding parts.

The encapsulation of the high-pressure line system is advantageously done by an arrangement the same in bores provided in the cylinder head.

The last two embodiments are advantageously further developed in that the command rail is located close to the cylinder head in the crankcase, and that the Common rail by means provided in the crankcase and / or in the cylinder head Mounting openings has accessible high-pressure connections to which the injectors leading high pressure lines are connected. It is particularly advantageous here if the Mounting openings are arranged so that both the high pressure connections and the injectors and the high pressure lines are accessible and mountable. This enables one advantageous reduction in assembly and maintenance effort.

The mounting openings can either be closed by a cover, or it is advantageously provided that the cylinder head is constructed in several parts, and that the Assembly openings are closed by an easily removable part of the cylinder head.

According to a particularly advantageous embodiment, there is one in the internal combustion engine provided charge air pipe as this aforementioned easily removable part of the Cylinder head trained. It is particularly convenient to have the mounting holes on the side Cylinder head to be provided and closed by the charge air pipe.

The mounting openings and from the charge air pipe to the are advantageous here Air intake ducts leading combustion chambers of the internal combustion engine essentially in a row in a sealing surface between the cylinder head and the charge air pipe. This will the production of the openings and sealing surfaces on the cylinder head and on the charge air pipe much simplified. Furthermore, it is appropriate in this embodiment and it is from particular advantage through the mounting openings and the air inlet channels on the sealing surface to seal a common seal.

The advantage of the above-mentioned embodiments, in which the assembly openings through the charge air pipe are closed, it is that no additional mounting cover and Fasteners are required, and that only when replacing a single cylinder head the charge air pipe and the high pressure line leading to the injector of the relevant cylinder head must be solved, but not the common rail and the other high pressure lines must be dismantled.

Of particular advantage is an embodiment in which the charge air pipe runs parallel to Drainage channel running along the longitudinal axis of the crankcase for receiving on the injectors leakage and control fuel quantities in the leakage leading to the injectors and control fuel channels open. This can be developed so that the leakage and Control fuel channels are connected to the holes housing the injectors, wherein the injectors are designed so that they the leakage and control fuel amounts in the Drill holes. This leads to a further simplification of the fuel injection system.

It is convenient to pass the leak and control fuel channels through the mounting holes to allow contained sealing surface to pass through and in the sealing surface through the Seal the assembly openings and the charge air pipe against each other with a seal.

According to one embodiment, it is provided that the common rail for connection a line leading to the high pressure pump and / or a pressure sensor on at least one End is led out of the crankcase. It is advantageous to use the high pressure pump leading line and the pressure sensor at the same end on the common rail to join.

The following is an embodiment of the fuel injection system according to the invention explained using the drawing.

Figur 1

eine Querschnittsansicht durch einen wesentliche Bestandteile des Kraftstoffeinspritzsystems enthaltenden Teil des Zylinderkopfs einer Brennkraftmaschine entlang der Linie I-I in Figur 5;

Figur 2

eine Schnittansicht durch den gleichen Teil des Zylinderkopfs wie in Figur 1, jedoch in Längsrichtung der Brennkraftmaschine parallel versetzt entlang der Linie II-II in Figur 5;

Figur 3

eine Figur 1 entsprechende Querschnittsansicht einer weiteren Ausführungsform;

Figur 4

eine Figur 2 entsprechende Schnittansicht der Ausführungsfom nach Figur 3;

Figur 5

eine Draufsicht auf einen wesentliche Bestandteile des erfindungsgemäßen Kraftstoffeinspritzsystems enthaltenden Teil eines Zylinderkopfs einer Brennkraftmaschine;

Figur 6

einen Längsschnitt durch ein aus dem Kurbelgehäuse der Brennkraftmaschine herausgeführtes Ende der Common-Rail-Schiene des Kraftstoffeinspritzsystems entlang der Linie VI-VI in Figur 5; und

Figur 7

einen Längsschnitt durch das andere Ende der Common-Rail-Schiene im Bereich des Endes des Kurbelgehäuses der Brennkraftrnaschine (Schnittlinie VII-VII).

Show it:

Figure 1

a cross-sectional view through an essential component of the fuel injection system containing part of the cylinder head of an internal combustion engine along the line II in Figure 5;

Figure 2

a sectional view through the same part of the cylinder head as in Figure 1, but offset in the longitudinal direction of the internal combustion engine parallel along the line II-II in Figure 5;

Figure 3

a cross-sectional view corresponding to Figure 1 of a further embodiment;

Figure 4

a sectional view corresponding to Figure 2 of the embodiment of Figure 3;

Figure 5

a plan view of an essential component of the fuel injection system part of a cylinder head of an internal combustion engine according to the invention;

Figure 6

a longitudinal section through an end led out of the crankcase of the internal combustion engine of the common rail of the fuel injection system along the line VI-VI in Figure 5; and

Figure 7

a longitudinal section through the other end of the common rail in the region of the end of the crankcase of the internal combustion engine (section line VII-VII).

FIG. 1 shows a cross-sectional view of part of a cylinder head of an internal combustion engine, which shows essential components of the fuel injection system according to the invention. The The internal combustion engine has a crankcase 1, of which only a small part is shown in the figure and a plurality of cylinder heads, one cylinder head 2 of which is shown. In the cylinder head 2 is in a bore 29 a high pressure line 5 with intermediate storage 37 and backflow throttle arranged. The high-pressure line 5 leads via a pressure piece 42 to a fuel injector 36 (see FIG. Fig.5), for injecting fuel into the associated combustion chamber, the cylinder 14, the Internal combustion engine is used. The high-pressure line 5 is in the area of the line section 7 a connector 8 connected to a common rail 3. The common rail 3 will supplied by a high-pressure pump, not shown in the figure, and fuel there in the manner of a Oil-elastic memory held under pressure and when the fuel injector 36 is actuated a predetermined time and in a predetermined amount in the combustion chamber Internal combustion engine delivered. in this respect the fuel injection system shown corresponds to that State of the art.

The common rail 3 is in the upper, the cylinder head 2 facing part of the Crankcase 1 arranged in a parallel to the longitudinal axis of the same channel 6. In the exemplary embodiment shown, the common rail 3 is in the form of a tube formed and the channel 6 is parallel to the longitudinal axis of the crankcase 1 Longitudinal bore provided.

As can be seen from Figure 7, which is a longitudinal section through one of the ends of the Common rail shows, this is mounted by means of O-rings 23 in the crankcase 1, wherein these O-rings 23 are arranged in grooves 24 in the longitudinal bore 6.

As can also be seen from FIG. 1, there is an assembly opening 28 on the side of the cylinder head 2 provided through which the high pressure lines 5 and 7 and the connection 8 of the High-pressure line 7 on the common rail 3 accessible and mountable and removable are.

On the side of the internal combustion engine, a charge air pipe 4 is arranged, which the supply of preferably by means of an exhaust gas turbocharger compressed air to the combustion chambers of the Internal combustion engine is used.

In Figure 2 is an inlet duct leading from the charge air pipe 4 to the combustion chamber of the internal combustion engine 15 to see the camshaft 13 and a tappet 16 of the valve train of the internal combustion engine. How can be seen, the inlet channel 15 is substantially in alignment with the Assembly opening 28, that is, in an internal combustion engine with cylinders arranged in series 14, the mounting openings 28 and the air inlet channels 15 are essentially in a row the side of the cylinder head or cylinders, and have a common Sealing surface 33, on which one between the cylinder head 1 and the charge air pipe 4th provided seal 32 is arranged. During the air inlet duct 15 with the air duct Is part of the charge air tube 4 in connection, is the part located above the mounting opening 28 of the charge air pipe against the air-guiding part, so that the mounting opening 28th through the charge air tube 4 through the seal 32 is hermetically sealed to the outside. Due to its location and arrangement, the charge air tube 4 can be part of the two parts trained cylinder head 2 are viewed. The seal 32 is for the air inlet channels 15 and the mounting openings 28 of the cylinder heads 2 supplied by the charge air pipe 4 together intended. Alternatively, the mounting openings 28 can also be made using individual sealing lids to be introverted.

By mounting the common rail 3 in recordings of the crankcase 1 of the Internal combustion engine and the hermetic seal of the high pressure lines 5 and Injectors 36 accommodating space through the charge air pipe 4 are the common rail 3 and the high-pressure lines 5 and 7 and the fuel injectors 36 to the outside in a liquid-tight manner encapsulated, forming a liquid-tight leakage space 11, which is due to anyone absorbs fuel leaking from the screw connections. Any leakage quantities of this type collect in a leakage discharge 9 at the bottom of the channel 6. A control hole provided on the level of the leakage discharge 9 in the Crankcase 1 of the internal combustion engine enables leakage quantities to occur display.

A leakage leads from the bores 29, which are in connection with bores 38 Control fuel channel 30 to a parallel to the crankcase longitudinal axis in the charge air pipe 4th running drainage channel 12, which is used to receive leakage from the injectors 36. and control fuel amounts. Such leakage and control fuel quantities, which directly to the Injectors 36 do not occur in the area provided in the common rail 3 Leakage space 11 given, but collect within the bore 38 and enter the Leak and control fuel channel 30 to the drain channel 12, via which they to the fuel injection system to be led back. The leak and control fuel channels 30 also pass through the sealing surface 32 and the mounting openings 28 and the air inlet channels 15 containing are sealed there by seals 31.

As shown in Figure 3, the common rail 3 between the crankcase 1 and one Charge air pipe 4 arranged. The parts of the fuel injection system essentially correspond those of Figure 1 and are therefore designated by the same reference numerals. The from Crankcase 1 and the charge air tube 4 formed channel 40 runs parallel to the longitudinal axis of the Crankcase. The channel 40 forms together with the leakage space 11, which is from the charge air pipe 4th and a cap 39 and the cylinder head 2 and crankcase walls limited is a liquid-tight room for the common rail. By disassembling the Cap 39 and / or the charge air tube 4 are the parts of the high pressure line system in easily accessible. The cover consisting of the charge air pipe offers one space-saving protection for the high pressure line system.

FIG. 4, which shows a view corresponding to FIG. 2 of the exemplary embodiment according to FIG. 3, shows the storage of the common rail on the crankcase by means of clamps 41, the Crankcase are screwed. Instead of storage with clamps, it is also possible to Common rail rail analogous to the exemplary embodiment according to FIGS. 1 and 2, as in FIG. 7 shown to be stored with O-rings, which are introduced between charge air pipe 4 and crankcase 1 are.

Figure 5 is a plan view of a cylinder head of an internal combustion engine in which an injector 36 is included a leakage and control bore 38 is shown. The high pressure line 5 is over a Pressure piece 42 connected to the injector 36. The holes 38 and 29 are for the removal of Leakage and control fuel combined.

As can be seen from FIG. 6, the common rail 3 is at one end of the crankcase 1 led out of this and with a connection 25 for one to which the common rail 3 fuel-supplying high pressure pump and a connection 26 for a pressure sensor Provide monitoring of the pressure in the common rail 3. These connections 25 and 26 are in a shield 20 covering the lead-out end of the common rail 3 provided that by means of O-rings 22 arranged in grooves 24, the common rail 3 is stored and sealed against the crankcase 1 by means of an O-ring 27. The end of Common rail 3 is screwed into an internal thread provided there Sealing plug 35 closed with a sealing plate. Also visible in Figure 6 is a Longitudinal section through the connection 8 for the high pressure line 7, which from a leakage space 21st is surrounded. All connections of high pressure lines on the common rail 3 are through Conical seals and screw plugs realized.

Figure 7 shows the second end of the common rail 3, which is located at the end of the Crankcase 1, which has a gear train for controlling intake and exhaust valves Comprises internal combustion engine, only one camshaft gear 17 is shown. This end is by means of O-rings 23 arranged in grooves 24 in the bore 6 and at the same time against these sealed. By screwing into an internal thread provided there Sealing plug 19 with sealing plate, this end of the common rail 3 is closed.

LIST OF REFERENCE NUMBERS

1

crankcase

2

cylinder head

3

Common-rail track

4

Charge air pipe

5

High-pressure line

6

drilling

7

High-pressure line

8th

Connection of the high pressure line

9

leakage discharge

10

Cylinder head cover

11

leakage chamber

12

Leaking fuel discharge channel

13

camshaft

14

cylinder

15

intake port

16

tappet

17

camshaft

18

plugs

19

plugs

20

shielding

21

leakage chamber

22

O-ring

23

O-ring

24

groove

25

Connection for high pressure pump

26

Connection for pressure sensor

27

O-ring

28

mounting hole

29

Hole for injector

30

Leakage and pilot fuel quantity channel

31

poetry

32

poetry

33

sealing surface

34

poetry

35

plugs

36

injector

37

cache

38

drilling

39

cap

40

channel

41

brackets

42

Pressure piece

Claims (23)

1. Fuel injection system for an internal combustion engine, especially a diesel engine, which has a crankcase (1) and one or more cylinder heads (2), with fuel injectors (36) for injecting fuel into the combustion chambers of the internal combustion engine and with a common rail (3), which is supplied with fuel by a high-pressure pump and by which the fuel is supplied to the injectors (36) via a high-pressure line system, characterized in that the common rail (3) is accommodated in a duct (40), which is formed by walls of the crankcase and of a charge-air tube (4).
2. Fuel injection system according to Claim 1, characterized in that the common rail (3) is of tubular design.
3. Fuel injection system according to Claim 2, characterized in that the tubular common rail (3) is accommodated in longitudinal bores (6) of the crankcase (1) that run parallel to the longitudinal axis of the crankcase (1).
4. Fuel injection system according to Claim 1 or 2, characterized in that holding devices (41) secured on the crankcase (1) are provided for the purpose of securing the common rail (3).
5. Fuel injection system according to one of Claims 1 to 4, characterized in that the common rail (3) is supported by means of O-rings (22, 23).
6. Fuel injection system according to one of Claims 1 to 5, characterized in that the common rail (3) is arranged in such a way as to be encapsulated in a fluid-tight manner.
7. Fuel injection system according to Claim 6, characterized in that the duct (6) or (40) accommodating the common rail (3) forms a fluid-tight leakage space (9), which is provided with means for draining off leakage quantities.
8. Fuel injection system according to Claim 7, characterized in that the leakage space (9) has an inspection bore for the purpose of indicating leakage quantities that occur.
9. Fuel injection system according to one of Claims 1 to 8, characterized in that the high-pressure lines (5, 7), including an intermediate reservoir (37), that connect the injectors (36) to the common rail (3) are arranged in an encapsulated manner within the internal combustion engine.
10. Fuel injection system according to Claim 8, characterized in that the injectors (36) are arranged in an encapsulated manner in bores (38) and the high-pressure lines (5) are arranged in an encapsulated manner in bores (29) of the cylinder head (2).
11. Fuel injection system according to Claim 9 or 10, characterized in that the common rail (3) is arranged close to the cylinder head (2) in the crankcase (1), and in that the common rail (3) has high-pressure connections (8), which are accessible through installation openings (28) provided in the crankcase (1) and/or in the cylinder head (2) and to which the high-pressure lines (5, 7) leading to the injectors (36) are connected.
12. Fuel injection system according to Claim 11, characterized in that both the high-pressure connections (8) and the injectors (36) and the high-pressure lines (5, 7) are accessible and can be installed through the installation openings (28).
13. Fuel injection system according to Claim 11 or 12, characterized in that the installation openings (28) are closed by means of closure covers.
14. Fuel injection system according to Claim 10 or 11, characterized in that the cylinder head (2) is of multi-part design, and in that the installation openings (28) are closed by an easily removable part of the cylinder head (2).
15. Fuel injection system according to Claim 14, characterized in that the easily removable part of the cylinder head (2) is a charge-air tube (4).
16. Fuel injection system according to Claim 15, characterized in that the installation openings (28) are provided laterally on the cylinder head (2) and are closed by the charge-air tube (4).
17. Fuel injection system according to Claim 16, characterized in that the installation openings (28) and air-inlet ducts (15) leading from the charge-air tube (4) to the combustion chambers of the internal combustion engine are arranged essentially in a row in a sealing surface (33) between the cylinder head (2) and the charge-air tube (4).
18. Fuel injection system according to Claim 17, characterized in that the installation openings (28) and the air-inlet ducts (15) are sealed off at the sealing surface (33) by a common seal (32).
19. Fuel injection system according to one of Claims 15 to 18, characterized in that the charge-air tube (4) has an outflow duct (12) which runs parallel to the longitudinal axis of the crankcase, which is intended to receive quantities of leakage or control fuel arising at the injectors (36) and into which leakage and control fuel ducts (30) leading to the bores (29) open.
20. Fuel injection system according to Claim 19, characterized in that the leakage and control fuel ducts (30) are connected to the bores (29) and (38) that accommodate the injectors (36) and high-pressure lines (5), and in that the injectors (36) are designed in such a way that they discharge the quantities of leakage and control fuel into the bores (38).
21. Fuel injection system according to Claim 19 or 20, characterized in that the leakage and control fuel ducts (30) pass through the sealing surface (33) containing the installation openings (28) and are sealed off in the sealing surface (33) by seals (31).
22. Fuel injection system according to one of Claims 1 to 21, characterized in that the common rail (3) is passed out of the crankcase (1) at at least one end for the purpose of connecting a line (25) leading to the high-pressure pump and/or connecting a pressure sensor (26).
23. Fuel injection system according to Claim 22, characterized in that the line (25) leading to the high-pressure pump and the pressure sensor (26) are connected to the common rail (3) at the same end.

Images