EP2097620B1 - Crank case ventilator - Google Patents

Abstract

The present invention relates to a ventilation device (5) for ventilating a crankcase (6) of an internal combustion engine (1), particularly in a motor vehicle, comprising a ventilation line (26), which is connected at the input side to the crankcase (6) of the internal combustion engine (1) in the mounted state, and which is connected at the output side to a fresh gas line (3) feeding fresh gas to the internal combustion engine (1), a ventilation line (27), which in the mounted state is connected to the fresh gas line (3) at the input side and to the crankcase (6) at the output side. A separator (28) is arranged in the ventilation line (26) to remove pollution from the gas that is discharged from the crankcase (6) and a pressure valve (3) is arranged in the ventilation line (26) to control the gas volume discharged from the crankcase (6). In order to increase the smoothness of running of the internal combustion engine (1) in idle, the ventilation device (5) comprises a locking device (37) for locking the ventilation line (27).

Description

The present invention relates to a venting device for venting a crankcase of an internal combustion engine, in particular in a motor vehicle. The invention also relates to an operating method for such a crankcase ventilation device.

During operation of an internal combustion engine, namely a piston engine, so-called blow-by gases enter the crankcase via leaks between the pistons and the cylinders. With the help of a venting these blowby gases are removed from the crankcase and usually introduced into a fresh gas supplied to the engine with fresh gas line (eg DE 202005 003 462 U1 ). The venting device usually comprises a separator arranged in a blow-by gas venting from the crankcase, with the aid of which impurities, preferably oil and oil mist, can be removed from the discharged gas in order, for example, to return it to the crankcase. Such a separator works the better, the greater the pressure difference applied thereto. At partial load of the internal combustion engine prevail in the fresh air line, in particular downstream of a Throttle device, relatively high negative pressures, with which a correspondingly large pressure difference at the separator can be realized. However, the amount of blowby gas entering the crankcase at part load is comparatively small. Nevertheless, in order to be able to use the large differential pressure to increase the efficiency of the separator, it is basically possible to equip the ventilation device with a ventilation line which extracts fresh gas, ie usually air, from the fresh gas line and introduces it into the crankcase. This makes it possible to dissipate more gas from the crankcase at part load as blow-by gas enters the crankcase.

However, it has been shown that internal combustion engines, in which such ventilation of the crankcase is carried out, run extremely restless in idle mode. On the one hand, this is perceived as disturbing by the respective vehicle driver and, on the other hand, leads to increased consumption and emission values.

The present invention is concerned with the problem of providing for a venting device or for an associated operating method, an improved embodiment, which is characterized in particular by an increased smoothness of the engine equipped with the venting device in idle mode.

This problem is solved according to the invention by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of greatly reducing or disabling or blocking the ventilation provided for the part-load operation for idling operation. By this measure, the discharged via the vent line from the crankcase gas quantity is significantly reduced, namely about the entering into the crankcase blow-by amount of gas. Although the reduction in the amount of gas removed via the vent line reduces the effectiveness of the separator, this can readily be accepted, since only comparatively little blowby gas is produced during idling operation anyway. The reduction of the amount of gas discharged from the crankcase leads to the desired smoothness of the internal combustion engine when idling.

In this case, the invention utilizes the knowledge that the quantity of gas taken from the crankcase and introduced into the fresh gas line to increase the efficiency of the separator is the cause of the turbulent engine run in an internal combustion engine with a conventional venting device. In such a conventional venting device, the proportion of the gas introduced via the vent line into the fresh gas line is comparatively large in the amount of gas which is supplied to the internal combustion engine via the fresh gas line, as a result of which control systems which are supplied with that of the internal combustion engine Fresh gas quantity work as a reference variable, be significantly affected.

Due to the inventively proposed for idling operation strong reduction of discharged from the crankcase and the fresh gas line supplied gases, the proportion of these gases can be significantly reduced at the fresh gas supplied to the engine. Accordingly, the influence of the introduced into the fresh gas amount of gas on control systems of the internal combustion engine decreases. As a result, the synchronization of the internal combustion engine calms down.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be explained in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Fig. 1 bis 3

jeweils eine stark vereinfachte, schaltplan- artige Prinzipdarstellung einer Brennkraft- maschine mit Entlüftungseinrichtung bei un- terschiedlichen Betriebszuständen der Brenn- kraftmaschine,

Fig. 4 bis 8

jeweils stark vereinfachte Prinzipdarstel- lungen von Ventileinrichtungen unterschied- licher Ausführungsformen, und zwar (a) in einer Offenstellung und (b) in einer Schließstellung.

Show, in each case schematically,

Fig. 1 to 3

in each case a greatly simplified, circuit diagram-like basic representation of an internal combustion engine with venting device for different operating states of the internal combustion engine,

Fig. 4 to 8

each greatly simplified schematic representations of valve devices of different embodiments, namely (a) in an open position and (b) in a closed position.

According to the Fig. 1 to 3 includes an internal combustion engine 1, which is arranged for example in a motor vehicle, an engine block 2, a fresh gas line 3, an exhaust pipe 4 and a vent 5. The engine block 2 comprises a crankcase 6, in which a crank mechanism 7 is housed, a cylinder head 8, are arranged in the cylinder 9 for therein adjustable piston 10 of the internal combustion engine 1, a cylinder head cover 11 and an oil pan 12th

The fresh gas line 3 serves to supply the internal combustion engine 1 or the engine block 2 with fresh gas, in particular air, and contains an air filter 13 and downstream thereof an air flow meter 14. In the preferred embodiment shown here is in the fresh gas line 3 also arranged a charging device 15, by means of which the fresh gas can be brought to an elevated pressure level. In the example shown, the charging device 15 is the compressor of an exhaust gas turbocharger 16, the turbine 17 of which is arranged in the exhaust gas line 4 and drives the compressor 15 via a common shaft 18. Optionally, downstream of the charging device 15, a charge air cooler 19 may be arranged in the fresh gas line 3. In principle, the fresh gas line 3 may include a throttle device 20, for example a throttle valve, which is preferably arranged downstream of the charging device 15 and, if present, downstream of the charge air cooler 19.

The exhaust pipe 4 is used in a conventional manner to dissipate combustion exhaust gases of the internal combustion engine 1 of the engine block 2. Optionally, the internal combustion engine 1 may be equipped with an exhaust gas recirculation device 21, which is connected to the exhaust side of the internal combustion engine 1, e.g. at a disposed on the exhaust pipe 4 removal point 22, exhaust gas takes and this via an exhaust gas recirculation line 23 of the fresh gas side of the internal combustion engine 1, e.g. via a trained on the fresh gas line 3 introduction point 24, returns. In this exhaust gas recirculation line 23, an exhaust gas recirculation cooler 25 may be arranged.

The venting device 5 is used to vent the crankcase 6 and comprises a vent line 26 and a vent line 27. The vent line 26 is connected on the input side to the crankcase 6 and is on the output side connected to the fresh gas line 3. In contrast, the ventilation line 27 is connected on the input side to the fresh gas line 3 and on the output side to the crankcase 6.

The venting device 5 also has a separator 28, which is arranged in the venting line 26. The separator 28 is preferably a passive inertial separator such as e.g. a cyclone separator. The separator 28 is used to remove impurities, preferably oil and oil mist, from the transported in the vent line 26 gas. The impurities deposited in the separator 28 may be conveyed via a return line 29, e.g. be returned to the oil pan 12. Furthermore, the venting device 5, a pressure control valve 30 which is designed so that it can be controlled with the deductible from the crankcase 6 amount of gas. Usually, the pressure control valve 30 operates passively, so depending on the applied pressure difference.

In the embodiment shown, the vent line 26 is from the pressure control valve 30 via two return branches, namely via a first return branch 31 and a second return branch 32. The first return branch 31 is connected downstream of the charging device 15 with the fresh gas line 3. A corresponding first introduction point is designated 33. This first discharge point 33 of the venting device 5 is arranged downstream of the throttle device 20 on the fresh gas line 3. In contrast, the second is Return branch 32 upstream of the charger 15 is connected to the fresh gas line 3. A corresponding second introduction point 34 is preferably located relatively close to an inlet of the charging device 15 in order to reduce line losses. In any case, the second discharge point 34 of the venting device 5 is downstream of the air flow meter 14 and downstream of the air filter 13. Both the first return branch 31 and the second return branch 32 preferably each contain a check valve 35 which opens to the fresh gas line 3 and blocks towards the crankcase 6 ,

The vent line 27 is used for ventilation of the crankcase 6, so for the introduction of fresh gas, which is taken from the fresh gas line 3, in the crankcase 6. A removal point 36 is located upstream of the second inlet 34 and upstream of the air flow meter 14. Appropriately, the Removal point 36 downstream of the air filter 13. According to the invention, the ventilation device 5 for the ventilation line 27 on a locking device 37, with the aid of the ventilation line 27 can be locked. The locking device 37 is designed so that it can be switched between an open position and a closed or locked position. To realize a low-cost construction specifically adjustable intermediate positions are not provided. As in the Fig. 1 to 3 shown, this locking device 37 may be, for example, a check valve 38, the appropriate Way can be operated. This check valve 38 is arranged in the ventilation line 27.

Appropriately ventilation line 27 is provided with a throttled bypass 39, which bypasses the locking device 37. In the example shown, the throttled bypass 39 bypasses the check valve 38. In this way it is ensured that in the blocking position of the locking device 37 or in the blocking position of the check valve 38 still fresh gas via the vent line 27 can get into the crankcase 6, but throttled, so in a reduced extent. This bypass 39 serves to counteract the formation of an excessive negative pressure in the crankcase 6. In expedient embodiments of the locking device 37 and the check valve 38, said bypass 39 can be integrated into the blocking device 37 or into the check valve 38. Accordingly, in the Fig. 1 to 3 a block 39 and the locking device 37 and the check valve 38 comprehensive unit designated 40.

The ventilation line 27 is suitably throttled. In this way, the targeted maintenance of a negative pressure in the crankcase 6 can be achieved during operation of the venting device 5. In the example shown, the throttling of the ventilation line 27 is realized by means of a throttle device 41.

Optionally, the ventilation line 27 may be equipped with a non-return valve that the crankcase. 6 is permeable and locks in the opposite direction to the fresh gas line 3 out.

The venting device 5 in the Fig. 1 to 3 The embodiment shown operates as follows:

In a partial load operation of the internal combustion engine 1, the results in Fig. 1 reproduced constellation for the ventilation of the crankcase 6. The locking device 37 assumes its open position at partial load, ie the ventilation function is activated. At partial load, the first return branch 31 is activated and the second return branch 32 is deactivated. This is controlled by the much greater negative pressure downstream of the throttle device 20. Arrows 42 symbolize the amount of gas taken at part load via the vent line 26 and the first return branch 31 the crankcase 26 and introduced downstream of the charging device 15 and downstream of the throttle device 20 in the fresh gas line 3 becomes. This amount of gas 42 is significantly greater than the symbolized by an arrow 43 Blowby gas quantity that reaches the crankcase 6 at part load. The difference between the vented gas quantity 42 and the blowby gas quantity 43 is provided by an aeration amount 44, that is to say a fresh gas quantity 44 which is taken from the fresh gas line 3 via the venting line 27 and supplied to the crankcase 6. In partial load operation prevails downstream of the throttle device 20, a relatively large negative pressure, whereby it is possible to remove a relatively large amount of gas 42 the crankcase 6. The accruing Blowby gas quantity 43 depends on the operating state of the internal combustion engine 1, and the amount of fresh gas 44 serving for ventilation is automatically set when the blocking device 37 is open. In partial load operation according to Fig. 1 Thus, the amount of vent 42 corresponds to the sum of blowby gas amount 43 and aeration amount 44.

Fig. 2 shows the internal combustion engine 1 and the venting device 5 at full load of the internal combustion engine 1. At full load, the second return branch 32 is activated, while the first return branch 31 is deactivated. The deactivation of the first return branch 31 via the non-return valve 35 disposed therein and the at full load downstream of the charging device 15 and downstream of the throttle device 20 adjusting positive pressure.

At full load, the venting device 5 can now refer to the crankcase 6 via the vent line 26 and the second return branch 32, which is about as large as the blowby gas quantity 46 entering at full load into the crankcase 6. The venting amount 45 is expediently slightly larger as the blowby gas quantity 46 in order to avoid an overpressure in the crankcase 6 can. Since at full load substantially discharged from the crankcase 6 bleed amount 45 is the same size as the entering into the crankcase 6 Blowby gas quantity 46, the vent line 27 is virtually inactive at full load. However, the locking device 37 does not have to be transferred to its blocking position for this purpose. At full load corresponds to Fig. 2 the amount of ventilation 45 is approximately the blowby gas amount 46. Preferably, for the partial load operation, the pressure control valve 30 is designed so that the achieved at partial load ventilation amount 42 is about as large as that in full-load operation according to Fig. 2 achieved blowby gas volume 46.

Fig. 3 now shows a constellation that adjusts to the idling operation of the internal combustion engine 1. When idling, the first return branch 31 is active again, while the second return branch 32 is deactivated, because of the greater negative pressure at the first introduction point 33 relative to the second introduction point 34. The ventilation function is deactivated. For this purpose, the locking device 37 is switched to its blocking position, so that via the ventilation line 27 per se no fresh gas to the crankcase 6 can be performed. However, the bypass 39 allows, if necessary, a throttled introduction of fresh gas into the crankcase 6. This possibly flowing throttled amount of fresh gas is in Fig. 3 indicated by broken arrows 47. The discharged via the vent line 26 and the first return branch 31 from the crankcase 6 gas quantity is in Fig. 3 designated 48. The idling mode entering the crankcase 6 Blowby gas quantity is in Fig. 3 denoted by 49. Expediently, the pressure control valve 30 is designed so that it sets the venting amount 48 at part load about as large as the part-load resulting blowby gas 49th This means that at part load only a relatively small amount of gas through the venting device 5 in the fresh gas line. 3 arrives. This way you can the influence which the removal quantity 48 has on the control system of the internal combustion engine 1 can be reduced since the proportion of the removal quantity 48 at the total quantity of gas supplied to the internal combustion engine 1 is comparatively small. In idling mode according to Fig. 3 Thus, the amount of vent 48 corresponds substantially to the blowby gas amount 49.

The following are with reference to the Fig. 4 to 8 Several different embodiments of the locking device 37 explained in more detail. The individual embodiments are only schematic and are also purely exemplary, without limitation of generality and without claim to completeness.

Corresponding Fig. 4 (not part of the invention), the locking device 37 may be formed by a check valve 38 and be drivingly connected to its actuation with an actuator 50. The actuator 50 is, for example, an electric actuator 51, which is connected to a control unit, not shown, wherein the control unit knows the respective load state of the internal combustion engine 1. For example, the control unit is an engine control unit for operating the internal combustion engine 1. Fig. 4a shows the open position while Fig. 4b the closed position reflects.

At the in Fig. 5 (not part of the invention) shown embodiment, an actuator 50 is again provided, which is realized here by a pneumatic actuator 52. The pneumatic actuator 52 is, indicated by a double arrow 53, with a vacuum source connected, which generates a negative pressure when reaching the idle state, which is sufficient, a valve member 54 of the in Fig. 5a shown open position in the in Fig. 5b to show shown closed position. The valve member 54 is configured here as an example as a slide. In particular, the pneumatic actuator 52 can be connected via its pneumatic operative connection 53 downstream of the throttle device 20 to the fresh gas line 3, in particular to the first discharge point 33.

At the in Fig. 6 (Not part of the invention) shown embodiment, the vent line 27 acts on the input side with a flap 55 together, which may be in particular the throttle device 20 of the fresh gas line 3. In the in Fig. 6a shown open position, an inlet of the vent line 27 is fully open, so that the ventilation amount 44 can be sucked. In Fig. 6b the blocking position of the locking device 37 is reproduced. It can be seen that the inlet opening of the ventilation line 27 is closed by the flap 55. Through targeted leaks that form the bypass 39, only the throttled ventilation amount 47 can be sucked.

At the in Fig. 7 (not part of the invention) shown embodiment, the locking device 37 and the check valve 38 is realized by means of a rotary valve 56 which in the in Fig. 7a Open position shown activated an unthrottled passage, while in the in Fig. 7b shown blocking position a throttled passage, so the bypass 39 activated. The rotary valve 56 can, for example, preferably as Throttle valve configured throttle device 20 may be drive-coupled, whereby a dependent on the load state of the internal combustion engine 1 adjustment of the rotary valve 56 is achieved.

At the in Fig. 8 the embodiment shown, the locking device 37 and the check valve 38 has a pivoting slide 57 which is mounted pivotally adjustable about a pivot axis 58. On the pivot slide 57, a passage opening may be formed, which serves as a throttled bypass 39. The rotary valve 57 is drive-coupled, for example via a toothing with a component 59, which may be a part of a variable valve drive, not shown, moreover. Such a variable valve train is actuated load-dependent. Accordingly, said component 59 serves as an actuator 50, which actuates the pivoting slide 57 as a function of the load state. At the in Fig. 8a shown open position, the vent line 27 is fully open. At the in Fig. 8b shown blocking position of the pivoting slide 57 is completely pivoted into the cross section of the vent line 27. Preferably, however, this blocking position for the pivoting slide 57 is selected so that the passage 39 forming the passage opening is located in the cross section of the vent line 27.

Claims (6)

1. A ventilation device for ventilating a crank case (6) of an internal combustion engine (1), in particular in a motor vehicle,

   - with a ventilation line (26) which in the mounted state is connected on the input side to a crank case (6) of an internal combustion engine (1) and which is connected on the output side to a fresh gas line (3) feeding fresh gas to the internal combustion engine (1),

   - with a ventilation line (27) which in the mounted state is connected on the input side to the fresh gas line (3) and which is connected on the output side to the crank case (6),

   - with a separator (28) arranged within the ventilation line (26) to remove pollution from the gas discharged from the crank case (6),

   - with a pressure valve (30) arranged within the ventilation line (26) to control the gas volume discharged from the crank case (6),

   - with a locking device (37) for locking the ventilation line(27),

   - wherein for its actuation, the locking device (37) is drive-connected with an actuator (50) which is actuated depending on the load state of the internal combustion engine (1),

   - that the actuator (50) is a component (59) of a variable valve drive of the internal combustion engine (1).
2. The ventilation device according to claim 1,
   characterized in
   that the locking device (37) is formed by means of a lock valve (38) arranged within the ventilation line (27).
3. The ventilation device according to claim 1 or claim 2,
   characterized in
   that a throttled bypass (30) is provided for bypassing the locking device (37) or the lock valve (38).
4. The ventilation device according to claim 3,
   characterized in
   that the bypass (39) is integrated into the locking device (37) or into the lock valve (38).
5. The ventilation device according to any one of the claims 1 to 4,
   characterized in

   - that within the fresh gas line (3), a charging device (15) is arranged for pressure increase in the fresh gas,

   - that the ventilation line (26) has on the output side a first recirculation branch (31) which is connected downstream of the charging device (15) to the fresh gas line (3),

   - that the ventilation line (26) has on the output side a second recirculation branch (32) which is connected upstream of the charging device (15) to the fresh gas line (3).
6. The ventilation device according to any one of the claims 1 to 5,
   characterized in
   that the ventilation line (27) is throttled or includes a throttling device (41).

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