EP3523514B1 - Device for the ventilation of a crankcase of an internal combustion engine - Google Patents

Description

The invention relates to a device for venting a crankcase of an internal combustion engine, in particular a crankcase ventilation line.

In internal combustion engines - especially those for motor vehicles, with pistons or cylinders - gas can collect in a crankcase. It is also referred to as crankcase gas. This usually happens when the crankcase gas from a combustion chamber (or the cylinder) passes through a gap past a piston into the interior of the crankcase. The crankcase gas is also often referred to as "blow-by gas". It does not undergo exhaust gas purification before entering the crankcase. In addition, it often contains a high proportion of unburned or incompletely burned components. Therefore, the crankcase gas should not escape from the crankcase to the environment. However, the crankcase gas should be vented from the (usually airtight) crankcase to avoid pressure build-up in the crankcase. A pressure build-up is to be avoided in particular in order to avoid damage to the components of an internal combustion engine and its attachments. This applies in particular to seals.

Internal combustion engines are known in which the crankcase gas is removed from the crankcase and fed back to the combustion chambers so that after renewed combustion in the combustion chambers it can be fed to an exhaust gas system for exhaust gas aftertreatment (e.g. by means of a catalytic converter). This concept is often required by law for internal combustion engines and is called "crankcase ventilation".

Known systems have to externally arranged on the crankcase lines z. B. can be made of rubber. Such lines have the disadvantage that gas can escape from these crankcases in the event of a leak. This is disadvantageous, in particular due to legal requirements and/or environmental protection reasons.

In known systems, a diagnosis of the tightness of the crankcase ventilation lines is either not possible or can only be implemented with great effort (possibly using additional sensors). Even if a leak is detected, in systems of this type it cannot be ruled out that the internal combustion engine with the leak will continue to be operated, at least temporarily.

From the U.S. 2015/159596 A1 there is known a blow-by gas ventilation system for a supercharger-equipped internal combustion engine. From the EP 1 522 713 A2 an intake device of an internal combustion engine is known. From the DE 10 2004 012160 A1 a crankcase ventilation is known. From the DE 101 63 781 A1 a pressure control valve is known.

Proceeding from this, it is the object of the present invention to continue to solve or at least alleviate the technical problems described in connection with the prior art. In particular, an internal combustion engine is to be presented in which the risk of a leak, through which crankcase gas can get into the environment, is greatly reduced and possibly even eliminated, so that a complex diagnosis can also be dispensed with.

This object is achieved with an internal combustion engine according to the features of patent claim 1. Further advantageous refinements of the internal combustion engine are specified in the dependently formulated patent claims. The features listed individually in the patent claims can and can be combined with one another in any technologically sensible manner are supplemented by explanatory facts from the description, with further embodiment variants of the invention being shown.

The device according to the invention is an internal combustion engine having an engine block and a cylinder head. At least one crankcase and at least one cylinder, which is connected to at least one intake line, are arranged in the internal combustion engine. The crankcase is over a crankcase ventilation line connected to the at least one intake line. The crankcase ventilation line is arranged at least predominantly within the internal combustion engine, in particular within the engine block and/or within the cylinder head.

The internal combustion engine can be, for example, an internal combustion engine for a motor vehicle. The cylinder or cylinders form the combustion chamber(s) of the internal combustion engine, in which fuel can be combusted with air. The engine block surrounds the cylinders. The engine block is preferably realized as a cast part. The cylinder head completes the engine block. In addition to the engine block, the internal combustion engine has a cylinder head, which is preferably also implemented as a cast part. The engine block and cylinder head are firmly connected. The at least one cylinder is preferably arranged inside the engine block and closed on one side by the cylinder head. The crankcase forms a space delimited by the engine block and/or cylinder head. The crankcase forms a cavity within the engine block and/or within the cylinder head in which crankcase gas can collect.

• ein Luftfilter,
• eine Drosselklappe, und
• eine Kühlvorrichtung.

The at least one cylinder is supplied with air via the at least one intake line. The at least one intake line can be designed, for example, as a tube between the area surrounding the motor vehicle and the at least one cylinder. At least one of the following components is preferably arranged in the at least one intake line:

• an air filter,
• a throttle body, and
• a cooling device.

The crankcase ventilation line is provided in order to remove gas that collects in the crankcase from the crankcase and feed it back into the combustion process. This is preferably to the crankcase in which the Crankcase gases can collect, tied. Furthermore, the crankcase ventilation line is preferably connected to the intake line in such a way that the crankcase gases are sucked into the intake line due to a negative pressure prevailing in the intake line. The term "negative pressure" here means a negative pressure level relative to the pressure level in the crankcase. This means. in particular also that the crankcase ventilation line is preferably connected to a point of the intake line at which the pressure in the intake line (at least temporarily) is lower than in the crankcase. In internal combustion engines that have different pressure distributions in the intake line in different operating states, the crankcase ventilation line is preferably designed in such a way that the crankcase gas can be fed to a different point in the intake line depending on the operating state. For this purpose, for example, a system of several branched crankcase ventilation lines or branches on the crankcase ventilation line can be provided, which can be controlled via valves or flaps in such a way that, depending on the operating state of the internal combustion engine, a flow path provided for this operating state for the crankcase gas between the crankcase and the intake line is released is.

In order to be able to circumvent the problem described above that crankcase gas can get into the environment (especially if a line is not properly connected), the crankcase ventilation line is arranged at least predominantly inside the engine block inside or the cylinder head.

The arrangement of the crankcase ventilation line in the engine block or in the cylinder head is preferably realized in such a way that no gas can escape into the environment from the crankcase ventilation line. Preferably, the crankcase ventilation takes place exclusively within the engine block or within the cylinder head, so that the crankcase gas from the crankcase removed, and without leaving the engine block and the cylinder head can be passed through the crankcase ventilation line into an arranged within the crankcase area of the intake line. In this way it can be ensured that the crankcase gas cannot escape into the environment.

The fact that the crankcase ventilation line is arranged at least predominantly inside the engine block or the cylinder head means that at least 50%, preferably at least 75% and particularly preferably at least 90%, of the crankcase ventilation line are arranged inside the engine block or the cylinder head. The percentages refer to the length of the crankcase ventilation line measured along the course of the crankcase ventilation line. The percentages indicate the portion of the crankcase ventilation line located inside the engine block or the cylinder head in relation to the entire crankcase ventilation line (which can consist of several branches).

In a preferred embodiment, the internal combustion engine also has a compressor for compressing air in the intake line, with the crankcase ventilation line branching out and being connected to at least one first connection point on the intake line downstream of the compressor, and a line branch branching off at a junction point, which branch is connected to at least one second connection point is connected upstream of the compressor.

The connection between the crankcase ventilation line and the intake line is preferably arranged at the entry into a compressor for compressing the intake air. The introduction of the crankcase gas into the compressor inlet is an integral part of the compressor, regardless of the type of supercharging element used in the compressor (whether turbocharger or compressor). A crankcase ventilation line connection to the intake manifold at the discharge point is not detachable or an integral part of the assembly of the internal combustion engine. The same applies to a connection between the crankcase ventilation line and the crankcase (at an outlet of the crankcase from the engine). This connection is also not detachable or an integral part of the assembly.

The compressor can be an exhaust gas turbocharger, for example. In an internal combustion engine with a supercharger, a distinction can be made between supercharged operation (where the compressor compresses the air in the intake line so that the air is forced into the cylinder or cylinders) and naturally aspirated operation (where there is no compression and the air sucked into the cylinder(s). In suction operation, there is a vacuum in the intake areas of the cylinders (i.e. a lower pressure than in the crankcase), which is suitable for crankcase ventilation. Therefore, a crankcase ventilation line is preferably used in suction operation, which is connected to the intake area of the cylinder. In the present case, this is made possible by the part of the crankcase ventilation line that is connected to the at least one first connection point on the intake line downstream of the compressor. In this context, “downstream” means downstream in the (usually present) direction of flow. So here the at least one first connection point is arranged between the compressor and the cylinder or cylinders.

In supercharged operation, on the other hand, the pressure in the intake line downstream of the compressor is increased by the compressor, so that crankcase ventilation via this part of the crankcase ventilation line is not possible. In supercharged operation, crankcase ventilation preferably takes place via the line branch, which is connected to the at least one second connection point upstream of the compressor. In supercharged operation, upstream of the compressor there is a negative pressure (i.e. a lower pressure than in the crankcase), which is suitable for crankcase ventilation. This is due in particular to the fact that the compressor draws in the air to be compressed and thereby creates the negative pressure upstream. In suction operation, there is usually also a negative pressure at the at least one second connection point. However, this negative pressure is lower than the then existing negative pressure at the first intake point downstream of the compressor. Therefore, a branching of the crankcase ventilation line is advantageous, which enables a temporary suction at the first suction point and a temporary suction at the second suction point.

Depending on the operating state of the internal combustion engine, the crankcase ventilation can preferably take place via one or both branches of the crankcase ventilation line. A valve (flap) or changeover switch is preferably provided for this purpose, in particular at the branch-off point. It is possible that the valve itself is the branch point. The valve can be passive or switchable. A passive valve is brought into the desired position immediately by the pressure differences that occur at the various intake points. An active valve is actively (possibly electronically) controlled in order to establish a connection to the desired intake point.

In a further preferred embodiment of the internal combustion engine, a plurality of cylinders is provided. At least one first connection point is provided for each of the cylinders.

The intake line is preferably branched in such a way that it is connected individually via a corresponding branch to the respective intake area of each cylinder. The respective first connection point of a cylinder is preferably arranged in the corresponding branch of the intake line. This allows the crankcase gas to be evenly distributed to all cylinders. In any case, this applies to the suction operation of the internal combustion engine, in which the crankcase ventilation takes place via the first connection points.

In a further preferred embodiment of the internal combustion engine, the line branch is arranged partially outside the internal combustion engine and is connected to the intake line via a non-detachable connection at the first connection point.

The wording "outside the internal combustion engine" means in particular that the branch line is not arranged inside the engine block and not inside the cylinder head.

The design of the internal combustion engine can result in the intake line being arranged in such a way that the line branch must run at least partially outside the crankcase. This can apply in particular if a compressor is not molded directly onto the engine block or onto the cylinder head. This external part of the line branch is preferably kept as short as possible. Preferably, at least the part of the branch line on the outside is made of a material and designed in such a way (in particular with regard to a material thickness of a line wall) that tightness is ensured over the entire life cycle of the motor vehicle. In particular, it is preferred that the material of the external part of the branch line is selected in such a way that it shows the least possible signs of aging, in particular with regard to material properties that are relevant for the tightness of a line (porosity, rigidity, flexibility, brittleness, permeability to gas, Etc.). In particular, the part of the line branch lying on the outside can also be formed from a combination of several coaxially arranged lines which, as a whole, particularly reliably prevent gas escaping from the interior of the line branch. Preferably, this power branch is also not individually detachable, possibly integrally connected to the parts of the crankcase ventilation line arranged inside the internal combustion engine.

A non-detachable connection is to be understood in the present sense as meaning that the connection between the charging element and the engine-internal crankcase ventilation line is inevitable during repair work.

The non-releasable connection is preferably also to be understood as meaning a connection that cannot be released without damaging a component, in particular the crankcase ventilation line, the intake line and a connecting part which may be arranged in between. This ensures that the connection can no longer be loosened after factory assembly (during which, for example, a leak test was carried out). Then there is also no risk of an only partial, incomplete connection when it is restored. The non-releasable connection is preferably designed in such a way that it cannot and does not have to be released over the entire life cycle of the motor vehicle. In particular, it is preferred that the internal combustion engine is constructed in such a way that all possible repairs (including, for example, the removal and installation of components) can be carried out without the existence of the non-detachable connection being a hindrance.

In a further preferred embodiment of the internal combustion engine, the line branch is arranged at most 25% outside of the crankcase. A portion of the line branch outside the crankcase is preferably designed to be as short as technically possible.

The condition mentioned relates to a length of the branch line, which is measured along the course of the branch line. With such a short line branch, the risk of a leak in the part of the line branch arranged outside the crankcase can be reduced. It is preferred that the line branch is only arranged at most 5% outside of the crankcase. Furthermore, it is preferred that the part of the line branch located outside the engine block or the cylinder head is at most 20 cm [centimeters], in particular only 10 cm long.

In a further preferred embodiment of the internal combustion engine, the branch line has a check valve (flap) which is arranged inside the internal combustion engine. In further embodiment variants, however, it is also possible to design a check valve as an integral part of a compressor (in particular a compressor bend).

The wording “within the internal combustion engine” means in particular that the branch line is arranged inside the engine block or inside the cylinder head (also called cylinder head cover).

As described above, the crankcase ventilation line is configured to direct gas from the crankcase into the intake line. However, depending on the operating state of the internal combustion engine, the pressure in the intake line can also be greater than the pressure in the crankcase. This is especially true for the pressure downstream of a compressor. In this case, air could get into the crankcase via the crankcase ventilation line and increase the pressure there.

In particular, via the line branch, air can get from the intake line into the crankcase, as described. Therefore, the check valve is provided in the branch line. The passage direction of the check valve is preferably oriented from the branch point to the second connection point. The non-return valve, in particular in the described orientation of the passage direction, can preferably prevent air from getting into the crankcase from the intake line as described. The fact that the non-return valve is arranged within the internal combustion engine can significantly reduce the risk of leakage and thus of crankcase gas escaping, particularly in the case of this component, which is prone to leaks. Preferably the non-return valve is integrated into the internal combustion engine in such a way that it is impossible for gas to escape from the non-return valve (flap) into the environment.

In a further preferred embodiment of the internal combustion engine, a control valve (also called a control unit) is provided within the internal combustion engine, via which the crankcase ventilation line is connected to the crankcase.

The wording “within the internal combustion engine” means in particular that the control valve (control unit) is arranged inside the internal combustion engine, in particular inside the engine block or inside the cylinder head.

A control valve (control unit) means a device with which ventilation of the crankcase can be controlled in a targeted manner via the crankcase ventilation line, for example via an electronic control intervention.

The control valve (control unit) is preferably set up to keep a pressure in the crankcase at a desired level or below a desired level. In addition, it is preferred that the control valve (control unit) is used for switching (in different operating states of the internal combustion engine) between the branches of the crankcase ventilation line as described above. Preferably, the control valve (control unit) has an inlet which is connected to the crankcase to be vented. In addition, the control valve preferably has two outlets, one for each of the branches of the crankcase ventilation line. In the case of a crankcase ventilation line with more than two branches, the control valve preferably has an outlet for each branch of the crankcase ventilation line. The control valve is preferably arranged inside the crankcase. As with the check valve described above, it can be achieved that a leak of the control valve is avoided. The control valve is preferably integrated into the internal combustion engine in such a way that it is impossible for gas to escape from the control valve into the environment.

The control valve can prevent the pressure in the crankcase from becoming too low. Under-pressure in the crankcase can increase the build-up of crankcase gas to an undesirable degree by actively drawing gas from the cylinders past the pistons and into the crankcase. In addition, damage to other components such as seals can also occur due to a particularly low pressure, which can be avoided by using a control valve.

The control valve is preferably a PCV valve . The control valve can be volume flow or mass flow controlled or pressure controlled.

In a further preferred embodiment of the internal combustion engine, the part of the crankcase ventilation line running inside the engine block and/or the cylinder head is implemented as recesses inside the material of the engine block and/or the cylinder head.

In any case, a line realized by cutouts in a block of material cannot leak between its ends. Therefore, in this embodiment, crankcase gas leakage can be prevented particularly effectively.

In a further preferred embodiment of the internal combustion engine, the crankcase ventilation line is implemented as a cast or drilled channel.

If the engine block and/or the cylinder head is/are realized as a cast part or as two cast parts, a duct cast therein is particularly well protected against leakage.

The invention is preferably used in a motor vehicle with an internal combustion engine as described above.

The particular advantages and design features described above for the internal combustion engine can be applied and transferred to the motor vehicle described.

Fig. 1:

eine schematische Darstellung eines Kraftfahrzeugs mit einer Verbrennungskraftmaschine,

Fig. 2:

eine perspektivische Darstellung einer Verbrennungskraftmaschine mit einer Kurbelgehäuseentlüftungsleitung gemäß Stand der Technik,

Fig. 3:

eine perspektivische Darstellung einer beschriebenen Verbrennungskraftmaschine mit einer Kurbelgehäuseentlüftungsleitung, und

Fig. 4:

eine Schnittdarstellung der Verbrennungskraftmaschine aus Fig. 3.

The invention and the technical environment are explained in more detail below with reference to the figures. The figures show particularly preferred exemplary embodiments to which the invention is not limited. In particular, it should be pointed out that the figures and in particular the proportions shown are only schematic. Show it:

Figure 1:

a schematic representation of a motor vehicle with an internal combustion engine,

Figure 2:

a perspective view of an internal combustion engine with a crankcase ventilation line according to the prior art,

Figure 3:

a perspective view of an internal combustion engine described with a crankcase ventilation line, and

Figure 4:

a sectional view of the internal combustion engine 3 .

1 shows schematically a motor vehicle 1 with an internal combustion engine 2 having a crankcase 3 with a cavity 17. Four cylinders 4 are arranged on the crankcase 3, which are each connected to an intake line 5 via an intake area 9. The intake line 5 has an air filter 8 , a throttle valve 21 and a cooling device 22 . Furthermore, the cylinders 4 are connected to an exhaust pipe 6 via outlet areas 10 .

A compressor 7 designed as an exhaust gas turbocharger is connected both to the intake line 5 and to the exhaust line 6 . A crankcase ventilation line 11 is arranged predominantly inside the internal combustion engine 2 . The crankcase ventilation line 11 is connected to the four first connection points 13 on the intake line 5 in the intake areas 9 downstream of the compressor 7 . A line branch 12 of the crankcase ventilation line 11 branches off at a branch point 25 . The line branch 12 is connected to the intake line 5 upstream of the compressor 7 at a second connection point 14 , which is designed as a non-detachable connection 18 . A control valve 15 is arranged at the junction point 25 . The line branch 12 has a check valve 16 within the internal combustion engine 2 . The passage direction of the check valve 16 is oriented from the branch point 25 towards the second connection point 14 .

2 shows an internal combustion engine 2 according to the prior art. An external line 26, which is designed as a rubber hose, can be seen. The external line 26 is connected externally to a crankcase 3 and an intake line 5 via detachable connections and is used to ventilate the crankcase 3. The external line 26 cannot reliably prevent crankcase gas from escaping into the environment, and a diagnosis of leaks is only possible possible with great effort.

3 1 shows an internal combustion engine 2 as described above with a crankcase 3. A crankcase ventilation line 11 is predominantly arranged inside an engine block 24 or a cylinder head 23. FIG. Furthermore, the crankcase ventilation line 11 is connected here to an intake line 5 via a non-detachable connection 18 at a second connection point 14 .

4 shows the internal combustion engine 2 3 in a more detailed representation. It can be seen that the crankcase ventilation line 11 is implemented with cutouts 19 which form a cast-in channel 20 .

Reference List

1

motor vehicle

2

internal combustion engine

3

crankcase

4

cylinder

5

intake line

6

exhaust pipe

7

compressor

8th

air filter

9

intake area

10

outlet area

11

Crankcase ventilation line

12

line branch

13

first connection point

14

second connection point

15

control valve

16

check valve

17

cavity

18

non-detachable connection

19

recess

20

cast channel

21

throttle

22

cooler

23

cylinder head

24

engine block

25

junction point

26

external line

Claims (10)

1. Internal combustion engine (2) having an engine block (24) and a cylinder head (23), at least one crankcase (3) and at least one cylinder (4) which is attached to at least one intake line (5) being arranged in the internal combustion engine (2), the crankcase (3) being connected to the at least one intake line (5) via a crankcase breather line (11), having, furthermore, a compressor (7) for compressing air in the intake line (5), the crankcase breather line (11) being branched and being attached to at least one first connector point (13) on the intake line (5) downstream of the compressor (7), and a line branch (12) which is connected to at least one second connector point (14) upstream of the compressor (7) branching off at a branching point (25), characterized in that at least 75% of the crankcase breather line (11) is arranged within the engine block (24) and/or within the cylinder head (23), and in that that part of the line branch (12) which is arranged outside the engine block (24) and the cylinder head (23) is at most 20 cm long.
2. Internal combustion engine (2) according to Claim 1, at least 90% of the crankcase breather line (11) being arranged within the engine block (24) and/or within the cylinder head (23).
3. Internal combustion engine (2) according to Claim 1 or 2, a plurality of cylinders (4) being provided, and one of the at least one first connector points (13) being provided for each of the cylinders (4).
4. Internal combustion engine (2) according to one of the preceding claims, the line branch (12) being arranged partially outside the internal combustion engine (2) and being connected to the intake line (5) via a non-releasable connection (18) at the first connector point (13) .
5. Internal combustion engine (2) according to one of the preceding claims, at most 25% of the line branch (12) being arranged outside the internal combustion engine (2) .
6. Internal combustion engine (2) according to one of the preceding claims, the line branch (12) having a check valve (16) which is arranged within the internal combustion engine (2).
7. Internal combustion engine (2) according to one of the preceding claims, a control valve (15) being provided within the internal combustion engine (2), via which control valve (15) the crankcase breather line (11) being attached to the crankcase (3).
8. Internal combustion engine (2) according to one of the preceding claims, that part of the crankcase breather line (11) which runs within the engine block (24) and/or the cylinder head (23) being realised as cut-outs (19) within the material of the engine block (24) and/or the cylinder head (23).
9. Internal combustion engine (2) according to one of the preceding claims, the crankcase breather line (11) being realised as a cast channel (20).
10. Motor vehicle (1) with an internal combustion engine (2) according to one of the preceding claims.

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