DE102015007155A1 - Low pressure generation in the crankcase for particle number reduction - Google Patents

Abstract

The invention relates to a device (V) for an internal combustion engine; in particular for generating negative pressure in a crankcase (1) and / or for venting a crankcase (1), with a crankcase (1), at least one combustion chamber (4), at least one oil separator (16.1) in communication with the crankcase (1) and at least one pressure adjusting device (17.1), which is designed to set a negative pressure in the crankcase (1) during operation, so that expediently the pressure difference between the crankcase (1) and the combustion chamber (4) is reduced.

Description

The invention relates to a device for an internal combustion engine, in particular a gas engine or another internal combustion engine, which is operable with Otto engine combustion process. The device is used in particular for generating negative pressure in a crankcase, expedient for reducing the particle number emissions, and / or for venting the crankcase. The invention further relates to a corresponding operating method.

It is common in diesel engines of motor vehicles, a venting of the crankcase in a connection point between an air filter and a compressor of an exhaust gas turbocharger. So-called blow-by air is guided into an oil separator. In the crankcase usually negative pressures in the order of about 30 mbar are generated. Until EURO-V legislation, for commercial vehicles, only the particle mass was limited. From EURO-VI legislation, for commercial vehicles, a limit for the number of particles must now be complied with. Because of the Otto engine combustion method of gas engines, a throttle valve is closed except for a small gap, especially in the operating states thrust and idle. In the intake manifold after the throttle valve creates a negative pressure relative to the environment. During the intake stroke, this results in a negative pressure in the combustion chamber of the engine, which is why a negative pressure with respect to the crankcase of the engine is established in the combustion chamber. As a result, gas from the crankcase is sucked into the combustion chamber ("reverse blow-by"). Due to the gas movement, engine oil, from the bushing / piston area, is conveyed into the combustion chamber. Due to the low intensity of the combustion in idle, or the non-existent combustion in the thrust, oil accumulates in the combustion chamber. If an increase in load occurs after a prolonged coasting or idling phase, the accumulated oil is burned by the increased flame intensity within a short period of time. The result is a high particle emission from oil residues resulting from combustion (oil ash). This effect is reinforced by the fact that the amount of oil in the combustion chamber is not taken into account in the fuel metering. In the combustion chamber there is a lack of oxygen, which promotes particle emission. The oil ash consists mainly of very small particles, which is why the emission of the particle number is more affected than the emission of particulate matter.

An object of the invention is to provide a way to reduce the number of particles emitted.

This object can be achieved with the features of the independent claims. Advantageous developments can be taken from the dependent claims and the following description of preferred embodiments of the invention.

The invention provides a device expedient for an internal combustion engine and in particular for generating negative pressure in a crankcase and / or for venting the crankcase. The device comprises a combustion chamber, a crankcase and at least one associated with the crankcase oil separator. The device further comprises at least one pressure adjusting device for adjusting a negative pressure in the crankcase in order to preferably reduce the pressure difference between the crankcase and the combustion chamber. The reduced pressure difference between the combustion chamber and the crankcase causes a reduced oil entry into the combustion chamber and / or a reduced reverse blow-by and thus in particular a reduced exhaust gas particle number emission, z. B. in the operating phases idle, light load and / or thrust of the internal combustion engine. The internal combustion engine expediently comprises a motor vehicle engine.

It is possible for the crankcase to be connected via a line device (eg venting device, line, line system, etc.) to a connection point with a charge air supply line for supplying charge air into the combustion chamber. The connection point is preferably arranged on the charge air supply line between a throttle element and the combustion chamber.

The conduit means may comprise an oil separator and / or a pressure adjuster. The pressure adjusting device may be integrated in the oil separator or arranged outside of the oil separator.

The oil separator of the conduit device is preferably connected to the crankcase via a venting element (eg venting line, venting stub, etc.) and / or an oil return device (eg oil return line, oil return stub, etc.). The oil return device is useful for the return of oil in the crankcase. The venting element is useful for venting the crankcase. The oil return device may, for. B. have a check valve.

The conduit means may in particular comprise a control means, which is preferably designed, the setting of the negative pressure in the crankcase to the operating state idle, light load and / or thrust of Limit internal combustion engine. The control means may also serve to prevent backflow of air into the crankcase and / or restrict the working area of the conduit means to the junction.

The control means is preferably a shut-off valve. The control means may be electrically controllable, for. B. from an engine control unit for controlling the internal combustion engine or limit switch, it may also z. B. be pneumatically actuated with an appropriate limit control or it can be designed as a self-switching vacuum valve.

The control means is preferably arranged between the connection point to the charge air supply line and the pressure adjustment device.

The conduit means may comprise a check valve. The check valve is preferably arranged between the connection point to the charge air supply line and the pressure adjustment device.

The line device is preferably connected in the charge air flow direction behind a throttle element with the charge air supply. In other words, the connection point can be formed behind a throttle element of the charge air supply line. Alternatively or additionally, the line device between the combustion chamber and a throttle element of the charge air supply into the charge air supply lead. The throttle element may, for. B. be a throttle.

The device may have an exhaust gas turbocharger.

In this case, it is possible for a vent line to branch off from the line device and for the vent line to be connected to an inlet connection in front of a compressor of a turbocharger. Alternatively or additionally, the vent line itself may have a check valve.

As an alternative or in addition to the line device, the device may have a line device (eg venting device, line, line system, etc.).

The line device is used in particular for connection to an inlet connection in front of a compressor of a turbocharger.

It is possible that the conduit device comprises an oil separator and / or a pressure adjusting device. The pressure adjusting device may be integrated into the housing of the oil separator or be arranged outside the housing of the oil separator.

The oil separator of the piping device is preferably connected to the crankcase via a venting element (eg vent line, bleed port, etc.) and an oil return device (eg oil return line, oil return port, etc.). The oil return device is useful for returning oil into the crankcase. The venting element is useful for venting the crankcase. The oil return device may, for. B. have a check valve.

The conduit device may expediently have a check valve between the pressure adjustment device and the introduction port.

The feature "pressure setting" is preferably to be interpreted broadly in the context of the invention and can be useful z. B. include a pressure control or pressure control.

The feature "line" is preferably to be interpreted broadly in the context of the invention and can be useful z. B. flexible or rigid pipes, pipes, hoses, connecting pieces, interfaces, etc. include.

The conduit means is preferably a venting device.

The conduit device is preferably a ventilation device.

In the embodiment with two Druckeinstelleinrichtungen preferably two adjustable (regular or controllable) operating pressures in the crankcase are possible.

The invention is not limited to a device as described herein, but also includes a motor vehicle, preferably a utility vehicle, in particular a bus or a truck, with a device as disclosed herein.

Moreover, the invention relates to an operating method, in particular for a device as disclosed herein and / or embodied with a device as disclosed herein. The device thus comprises a combustion chamber, a crankcase and at least one associated with the crankcase oil separator.

In the operating method, a negative pressure in the crankcase is adjusted by means of at least one pressure adjusting device in order to expediently reduce the pressure difference between the crankcase and the combustion chamber.

The operating method is used in particular for generating negative pressure in a crankcase and / or for venting a crankcase.

Further method steps result from the description of the device referred to in order to avoid repetition.

The disclosure made herein to the device applies mutatis mutandis, also for the operating method and is also suitably claimable claim.

The previously described embodiments and features of the invention can be combined with one another. Other advantageous developments of the invention are disclosed in the dependent claims or will become apparent from the following description of preferred embodiments of the invention in conjunction with the accompanying drawings.

1 shows a schematic representation of a device according to an embodiment of the invention, and

2 shows a schematic representation of a device according to another embodiment of the invention.

The embodiments described with reference to the figures are partially identical, so that similar or identical parts are provided with the same reference numerals, and to the explanation of which reference is also made to the description of the other embodiment or figure in order to avoid repetition.

1 shows a schematic representation of a device V for an internal combustion engine.

The device V comprises a crankcase 1 , a conduit means (venting means) X and an exhaust gas turbocharger 7 ,

The turbocharger 7 includes as usual a turbine 8th and a compressor 9 , In front of it is an air filter 10 , The reference number 20 indicates exhaust gas to the exhaust system. The reference number 21 indicates charge air to the intercooler, not shown.

The device V or the internal combustion engine comprises the crankcase 1 , one or more combustion chambers 4 , one or more pistons 3 , a crank mechanism 12 , one or more cylinder heads 2 , with one or more exhaust valves 5 and one or more intake valves 6 , The reference number 13 indicates an oil level in the crankcase 1 ,

The conduit means X connects the crankcase 1 at a connection point A in the charge air flow direction 22.1 behind a throttle 11 a charge air supply line 22 with the charge air supply line 22 , The charge air supply line 22 serves to supply charge air into the combustion chamber 4 , in particular to the inlet valve 6 or a charge air manifold. The reference number 22.1 indicates the charge air from the charge air cooler, not shown, or the flow direction of the charge air in the charge air supply 22 ,

The conduit means X comprises an oil separator 16.1 and a pressure adjusting device 17.1 for the crankcase pressure (eg a pressure regulator). The oil separator 16.1 is via a crankcase ventilation port 14.1 on the one hand and via an oil return line 14.3 and 14.4 with the crankcase 1 connected. In the oil return line 14.3 . 14.4 is a check valve 18.2 arranged. The oil separator 16.1 is over a line 14.2 with the pressure adjustment device 17.1 connected.

The conduit means X further comprises between the pressure adjusting means 17.1 and the junction A a check valve 18.1 and / or a controllable shut-off valve 19 , The reference number 14.5 shows the line between the check valve 18.1 and the shut-off valve 19 while the reference number 14.6 the line between the shut-off valve 19 and the junction A shows. The shut-off valve 19 is between junction A and the check valve 18.1 arranged.

Between the pressure adjusting device 17.1 and the check valve 18.1 goes from a preferably T-shaped pipe or hose 15 one with a check valve 18.3 provided vent line 14:14 for connection to an inlet port E in front of the compressor 9 of the turbocharger 7 serves, in particular between the compressor 9 and the air filter 10 ,

The administration 14:14 leads in particular in turbocharged engines to the inlet port E in front of the compressor 9 of the turbocharger 7 , The administration 14:14 is open when the pressure after the throttle 11 the pressure in front of the compressor 9 exceeds. In this case, the check valve 18.1 closed or is the shut-off valve 19 closed. The line from the pressure adjusting device 17.1 via connection point A into the charge air supply line 22 is open when the pressure in front of the compressor 9 the pressure after the throttle 11 exceeds what is especially the case when idling, light load or thrust of the internal combustion engine or the motor vehicle in general. The check valve 18.3 is closed. Due to the low pressure after the throttle 11 can a high negative pressure in the crankcase 1 be generated. In the process, the pressure in the crankcase becomes 1 via the pressure adjustment device 17.1 to control the negative pressure of the crankcase 1 regulated to a predetermined target value. Exceeds the pressure after the throttle 11 the target value, turns in the crankcase 1 minimal pressure after the throttle 11 one. Exceeds the pressure after the throttle 11 the pressure in front of the compressor 9 , causes the now open line 14:14 that is in the crankcase 1 a pressure in the range of the pressure in front of the compressor 9 established. The switching between the lines before compressor 9 (Management 14:14 ) and throttle 11 (Conduit X) is preferably done via a valve control by means of independently opening and closing valves, useful check valves. It should be mentioned that in naturally aspirated engines the line 14:14 and / or the valve control can be omitted.

2 shows a device V according to another embodiment of the invention.

The device V initially comprises a crankcase 1 and a conduit device X, which may be implemented substantially as in the previous embodiment. The line device X the 2 differs in particular characterized by the line device X the 1 that from her no guidance 14:14 branches. Instead of the preferably T-shaped pipe or hose 15 is the line 14.7 , which is so branch-free that an oil separator 16.2 and a pressure adjusting device 17.2 not with the inlet port E before the compressor 9 are connected. The administration 14.7 connects the pressure adjusting device 17.2 with a check valve 18.1 ,

The device V of 2 however, includes a piping device (venting device) Y. The piping device Y connects the crankcase 1 with the introduction port E before the compressor 9 of the turbocharger 7 ,

The line device Y comprises an oil separator 16.3 and a pressure adjusting device 17.3 , The pressure adjustment device 17.3 is via a pipe or connecting piece 14.9 with the oil separator 16.3 connected. The oil separator 16.3 is over a pipe element 14.8 and a check valve 18.4 having oil return line 14:10 . 14:11 with the crankcase 1 connected.

The line device Y points between the pressure adjusting device 17.3 and the introduction port E, a check valve 18.3 on. A vent line 14:12 connects the pressure adjusting device 17.3 with the check valve 18.3 while a vent line 14:13 the check valve 18.3 connects to the introduction port E.

In the 2 embodiment shown has the advantage of short lines and thus a fast response and two adjustable or regulated operating pressures in the crankcase 1 on.

With reference to the embodiments of the 1 and 2 the Druckeinstelleinrichtungen serve to a negative pressure of 0.1-500 mbar, preferably of over 100 or 150 mbar, in the crankcase 1 adjust the pressure difference between the crankcase 1 and the combustion chamber 4 resulting in a reduced reverse blow-by and thus a reduced number of emitted particles.

The reduction of the number of emitted particles results in particular from the fact that because of the reduced pressure difference between the combustion chamber 4 and crankcase 1 the so-called reverse blow-by is reduced and thereby in turn the oil entry from the crankcase 1 in the combustion chamber 4 is reduced.

The vacuum generation of 0.1-500 mbar, preferably of over 100 or 150 mbar, in the crankcase 1 is limited in particular to the critical operating conditions idle, light load and thrust, resulting in the controllable shut-off valve 19 is achievable.

The invention is not limited to the preferred embodiments described above. Rather, a variety of variants and modifications is possible, which also make use of the inventive idea and therefore fall within the scope.

Moreover, the invention also claims protection of the subject matter and the features of the subclaims independently of the features and claims referred to.

LIST OF REFERENCE NUMBERS

1

crankcase

2

cylinder head

3

piston

4

combustion chamber

5

outlet valve

6

intake valve

7

turbocharger

8th

turbine

9

compressor

10

air filter

11

Throttle element (throttle)

12

crankshaft

13

oil level

14.1

Crankcase ventilation port or line

14.2

Line from oil separator to pressure adjustment device (pressure regulator)

14.3

Oil return line before check valve

14.4

Oil return line to the oil sump

14.5

Bleed line from the check valve to the controlled shut-off valve

14.6

Vent line from the controlled shut-off valve to the charge air manifold downstream of the throttle element or into the charge air supply line downstream of the throttle element

14.7

Vent line from Druckeinstelleinrichtung to check valve throttle element, in particular without a branch

14.8

Crankcase ventilation port or line

14.9

Vent line from oil separator to pressure adjustment device (pressure regulator)

14:10

Oil return line before check valve

14:11

Oil return line to the oil sump

14:12

Vent line from pressure adjustment to check valve

14:13

Bleed line from the check valve to the inlet port before the compressor

14:14

Vent line to the inlet connection before the compressor

15

Pipe or hose with branch, z. B. T-shaped

16

oil separator

16.1

Oil separator for crankcase ventilation before compressor and / or after throttle element ( 11 )

16.2

Oil separator for crankcase breather after throttle element ( 11 )

16.3

Oil separator for crankcase ventilation before compressor

17th

Pressure adjusting device (pressure regulator) for crankcase pressure

17.1

Pressure adjustment device (pressure regulator) for crankcase pressure with crankcase ventilation before compressor and / or after throttle element ( 11 )

17.2

Pressure adjusting device (pressure regulator) for crankcase pressure in crankcase ventilation after throttle element ( 11 )

17.3

Pressure adjuster (pressure regulator) for crankcase pressure with crankcase breather upstream of compressor

18.1

Check valve in vent line after throttle element ( 11 )

18.2

Check valve in oil return line

18.3

Check valve in vent line before compressor

18.4

Check valve in oil return line

19

Controllable / controlled shut-off valve in venting device X

20

Exhaust gas to the exhaust system

21

Charge air to the intercooler

22

Charge air supply line for supplying charge air into the combustion chamber

22.1

Charge air flow direction

X

Ducting / venting system (venting system) for venting before compressor and / or after throttle element

Y

Breather / bleeder (bleed system) for bleeding from compressor

A

Connection point (charge air supply line and venting device X)

e

Inlet connection (vent Y before compressor)

V

Device for an internal combustion engine

Claims (17)

Device (V) for an internal combustion engine, in particular for generating negative pressure in a crankcase ( 1 ) and / or for venting a crankcase ( 1 ), with: a crankcase ( 1 ), at least one combustion chamber ( 4 ), at least one with the crankcase ( 1 ) associated oil separator ( 16 ), and at least one pressure adjustment device ( 17 ), which is designed to operate during operation a negative pressure in the crankcase ( 1 ), so that expedient the pressure difference between the crankcase ( 1 ) and the combustion chamber ( 4 ) is reduced. Device (V) according to claim 1, wherein the crankcase ( 1 ) via a line device (X) at a connection point (A) with a charge air supply line ( 22 ) for supplying charge air into the combustion chamber ( 4 ) connected is. Device (V) according to claim 2, wherein the conduit means (X) comprises an oil separator ( 16.1 . 16.2 ) and a pressure adjustment device ( 17.1 . 17.2 ). Device (V) according to claim 3, wherein the oil separator ( 16.1 . 16.2 ) via a venting element ( 14.1 ) and an oil return device ( 14.3 . 14.4 ) with the crankcase ( 1 ) and preferably the oil return device ( 14.3 . 14.4 ) a check valve ( 18.2 ) having. Device (V) according to one of claims 2 to 4, wherein the conduit means (X) comprises a control means (10). 19 ) and the control means ( 19 ) for at least one of the following: a backflow of air into the crankcase ( 1 ) to restrict the working range of the conduit means (X) to the connection point (A), and / or the setting of the negative pressure in the crankcase ( 1 ) to limit the operating state idle, light load and / or thrust of the internal combustion engine. Device (V) according to one of claims 2 to 5, wherein the conduit means (X) a check valve ( 18.1 ) between the pressure adjusting device ( 17.1 . 17.2 ) and the connection point (A), in particular between the pressure adjustment device ( 17.1 . 17.2 ) and the control means ( 19 ). Device (V) according to one of claims 2 to 6, wherein the conduit means (X) in the charge air flow direction ( 22.1 ) behind a throttle element ( 11 ) of the charge air supply line ( 22 ) with the charge air supply line ( 22 ) connected is. Device (V) according to one of claims 2 to 7, wherein of the conduit means (X) a vent line ( 14:14 ) branches off and the vent line ( 14:14 ) for connection to an inlet connection (E) in the flow direction in front of a compressor ( 9 ) of a turbocharger ( 7 ) serves. Device (V) according to claim 8, wherein the vent line ( 14:14 ) between the check valve ( 18.1 ) and the pressure adjustment device ( 17.1 . 17.2 ) branches off and preferably itself a check valve ( 18.3 ) having. Device (V) according to one of the preceding claims, wherein the crankcase ( 1 ) via a line device (Y) with an inlet connection (E) in the flow direction in front of a compressor ( 9 ) of a turbocharger ( 7 ) connected is. Device (V) according to claim 10, wherein the line device (Y) comprises an oil separator ( 16.3 ) and a pressure adjustment device ( 17.3 ). Device (V) according to claim 11, wherein the oil separator ( 16.3 ) via a venting element ( 14.8 ) and an oil return device ( 14:10 . 14:11 ) with the crankcase ( 1 ) and preferably the oil return device ( 14:10 . 14:11 ) a check valve ( 18.4 ). Device (V) according to one of claims 10 to 12, wherein the line device (Y) between the pressure adjusting device ( 17.3 ) and the introduction port (E) a check valve ( 18.3 ) having. Device (V) according to one of the preceding claims, wherein the at least one pressure adjustment device ( 17.1 . 17.2 . 17.3 ) is used, a negative pressure of 0.1 to 500 mbar, preferably of over 100, 150, 200, 250, 300 or even more than 500 mbar in the crankcase ( 1 ), adjust the pressure difference between the crankcase ( 1 ) and the combustion chamber ( 4 ), which in the sequence expediently leads to a reduced reverse blow-by and thus to a reduced number of emitted particles. Internal combustion engine, preferably a gas engine or other internal combustion engine with Otto-cycle combustion method, with a device (V) according to one of the preceding claims. Motor vehicle, preferably utility vehicle, with an internal combustion engine according to claim 15. Operating method for a device (V) with at least one combustion chamber ( 4 ), a crankcase ( 1 ) and at least one with the crankcase ( 1 ) associated oil separator ( 16 ), preferably for one and / or carried out with a device (V) according to one of claims 1 to 14, wherein by means of at least one pressure adjustment device ( 17 ) a negative pressure in the crankcase ( 1 ) is adjusted to expedient the pressure difference between the crankcase ( 1 ) and the combustion chamber ( 4 ) to reduce.

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