EP3101243B1 - Generation of a vacuum in the crankcase for reducing particles numbers - Google Patents

Description

The invention relates to a device for an internal combustion engine, in particular a gas engine or another internal combustion engine, which can be operated using an internal combustion engine method. The device is used in particular to generate negative pressure in a crankcase, expediently to reduce the number of particle emissions and / or to vent the crankcase. The invention further relates to a corresponding operating method. EP1411216 A1 describes a known device for venting a crankcase of an internal combustion engine. It is customary for diesel engines of motor vehicles to vent the crankcase into a connection point between an air filter and a compressor of an exhaust gas turbocharger. So-called blow-by air is fed into an oil separator. Negative pressures of the order of approximately 30 mbar are usually generated in the crankcase. Until the EURO-V legislation for commercial vehicles, only the particle mass was limited. From EURO VI legislation for commercial vehicles, a limit value for the number of particles must now also be observed. Due to the gasoline engine combustion process of gas engines, a throttle valve is closed to a small gap, particularly in the operating states of overrun and idling. A vacuum is created in the intake manifold after the throttle valve compared to the environment. As a result, a negative pressure is established in the combustion chamber of the engine during the intake stroke, which is why a vacuum is also established in the combustion chamber relative to the crankcase of the engine. As a result, gas is sucked out of the crankcase into the combustion chamber ("reverse blow-by"). Due to the gas movement, engine oil is pumped out of the liner / piston area into the combustion chamber. Due to the low intensity of the combustion at idle or the non-existent combustion in the overrun, oil accumulates in the combustion chamber. If the load increases after a longer overrun or idling phase, the oil accumulated is burned within a short period of time due to the increased flame intensity. There is a high particle emission due to the oil residues (oil ash) that occur during combustion. This effect is reinforced by the fact that the amount of oil in the combustion chamber is not taken into account when metering the fuel. There is a lack of oxygen in the combustion chamber, which promotes particle emissions. The oil ash mainly consists of very small particles, which is why the emission of the number of particles is affected more than the emission of the particle mass.

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

This object is achieved with the features of the independent claims. Advantageous further developments can be found in the dependent claims and the following description of preferred embodiments of the invention.

The invention provides a device expediently 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 oil separator connected to the crankcase. The device also includes at least one pressure setting device for setting 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 input into the combustion chamber and / or a reduced reverse blow-by and thus in particular a reduced exhaust gas particle number emission, for. B. in the operating phases of idling, low load and / or thrust of the internal combustion engine, for. B. a motor vehicle engine.

The crankcase is connected via a line device (e.g. ventilation device, line, line system, etc.) at a connection point to 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 line device can include the oil separator and / or the pressure setting device. The pressure setting device can be integrated in the oil separator or can be arranged outside the oil separator.

The oil separator of the line device is preferably connected to the crankcase via a breather element (e.g. breather line, breather connector, etc.) and / or an oil return device (e.g. oil return line, oil return connector, etc.). The oil return device is useful for returning oil to the crankcase. The venting element expediently serves to vent the crankcase. The oil return device can e.g. B. have a check valve.

The line device is expediently connected to the charge air supply line for supplying charge air into the combustion chamber, preferably in the charge air flow direction behind a throttle element of the charge air supply line.

The line device comprises a control means.

The control means is designed to limit the setting of the negative pressure in the crankcase to the operating state of idling, low load and / or thrust of the internal combustion engine.

The control means can also serve to prevent air from flowing back into the crankcase and / or to restrict the working range of the line device to the connection point.

It is also possible that the control means serves to control, in particular to switch between, the vent before a compressor of a turbocharger or to the connection point (connection point: charge air supply line and line device, in particular downstream of the throttle element).

The control means comprises a 3/2-way valve. The control means can in particular be designed to be electromagnetically or pneumatically controllable.

The control means can be electrically controllable, e.g. B. from an engine control unit or limit switch. It can also e.g. B. be pneumatically actuated with an appropriate limit control.

It is possible that the device comprises a pressure detection device, e.g. B. has a pressure sensor for detecting the charge air pressure downstream of the throttle element in the charge air supply line for supplying charge air into the combustion chamber.

The device preferably comprises an electrical or electronic control device for controlling the control means.

The control device is preferably the engine control device for controlling the internal combustion engine. The control means can z. B. directly connected to an electrical output of the engine control unit.

It is therefore possible that the engine control device for controlling the internal combustion engine is also used to control the control means.

It is possible for the control device to control the control means as a function of at least one of the following: a charge air pressure detected by the pressure detection device, a rotational speed of the internal combustion engine, the operating mode of the internal combustion engine (e.g. engine start, engine stop, idling, thrust, full load, part load) , Warm-up, and / or braking operation) and / or a current torque of the internal combustion engine.

It is also possible that the control device, depending on at least one of the following, has the control means vented before a compressor of a turbocharger or after the throttle element or into the charge air supply line: a charge air pressure detected by the pressure detection device, a rotational speed of the internal combustion engine, the operating mode the internal combustion engine (e.g. engine start, engine stop, idle, thrust, full load, partial load, warm-up, and / or braking operation) and / or a current torque of the internal combustion engine.

This is particularly advantageous in that the crankcase ventilation is made possible as a function of pressure according to the throttle valve and engine operating mode and / or engine speed.

There is also the possibility of diagnosing the pressure detection device and the control means, in particular the magnetic switch of the control means, for. B. on cable break and / or short circuit.

It is possible for the device to comprise a pressure detection device for detecting the pressure in the crankcase. In combination with the pressure detection device for detecting the charge air pressure downstream of the throttle element, diagnosis of the function of the control means and / or the pressure setting device is thus possible.

The pressure setting device can e.g. B. as a variable pressure regulator with setpoint specification, preferably via voltage or current characteristic (s). A pressure setpoint value that can be calculated in the control device can expediently be set, the setpoint value being adjustable in a closed control loop while simultaneously using the pressure detection device to detect the pressure in the crankcase.

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

The line device is preferably designed between the control means and the connection point without a check valve.

The pressure detection device for detecting the charge air pressure downstream of the throttle element can, however, also control the control means directly and / or without interposing the engine control unit.

The pressure detection device can in particular be designed as a limit switch, the z. B. directly controls a magnetic switch of the control means. Furthermore, a suitably analog voltage or current output of the pressure detection device can be connected to an electrical or electronic limit switch in order to control a magnetic switch of the control means.

It is possible for a control line (e.g. pipe and / or hose line) to go downstream of the throttle element for pneumatic control of the control means, preferably via a (vacuum) limit switch of the control means, depending on the charge air pressure downstream of the throttle element.

The device according to the invention thus enables control of the control means via the electrical / electronic motor control for the internal combustion engine and alternatively control of the control means without intervention in the engine control.

The line device is preferably connected in the charge air flow direction behind a throttle element to the charge air supply line. In other words, the connection point can be formed behind a throttle element of the charge air supply line. As an alternative or in addition, the line device can open into the charge air supply line between the combustion chamber and a throttle element of the charge air supply line. The throttle element can, for. B. be a throttle valve.

The device can have an exhaust gas turbocharger.

In this case it is possible that a ventilation line branches off from the control means and the ventilation line is used for connection to an inlet connection upstream of a compressor of a turbocharger. The vent line itself preferably has no check valve.

The feature "pressure setting" is preferably to be interpreted broadly within the scope of the invention and can expediently, for. B. include a pressure control or a pressure control.

The feature "line" is preferably to be interpreted broadly within the scope of the invention and can expediently, for. B. include flexible or rigid lines, pipes, hoses, connecting pieces, interfaces, etc.

The line device is preferably a venting device.

The invention is not restricted to a device as described here, but also comprises a motor vehicle, preferably a commercial vehicle, in particular a bus or a truck, with a device as disclosed herein.

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

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

The operating method is used in particular to generate negative pressure in a crankcase and / or to vent a crankcase.

Further method steps result from the description of the device to which reference is made in order to avoid repetitions.

The disclosure made on the device herein also applies mutatis mutandis to the operating method and in this respect can also be appropriately claimed.

Figur 1

zeigt eine schematische Darstellung einer Vorrichtung gemäß einer Ausführungs-form der Erfindung, und

Figur 2

zeigt eine schematische Darstellung einer Vorrichtung gemäß einer anderen Ausführungsform der Erfindung.

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 subclaims or result from the following description of preferred embodiments of the invention in conjunction with the attached figures.

Figure 1

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

Figure 2

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

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

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

The device V comprises a crankcase 1, a line device (ventilation device) X and an exhaust gas turbocharger 7.

The exhaust gas turbocharger 7 comprises, as usual, a turbine 8 and a compressor 9. An air filter 10 is arranged in front of it. The reference number 19 denotes exhaust gas to the exhaust system. The reference numeral 20 denotes charge air to the charge air cooler, 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 line device X connects the crankcase 1 at a connection point A in the charge air flow direction 21.1 behind a throttle valve 11 of a charge air supply line 21 to the charge air supply line 21. The charge air supply line 21 serves to supply charge air into the combustion chamber 4, in particular to the inlet valve 6 or a charge air manifold. The reference symbol 21.1 denotes the charge air from the charge air cooler (not shown) or the flow direction of the charge air in the charge air supply line 21.

The line device X comprises an oil separator 16 and a pressure setting device 17 for the crankcase pressure (for example a pressure regulator). The oil separator 16 is connected to the crankcase 1 via a crankcase ventilation connection 14.1 on the one hand and via an oil return line 14.3 and 14.4 on the other hand. In the oil return line 14.3, 14.4 a check valve 18.2 is arranged. The oil separator 16 is connected to the pressure setting device 17 via a line 14.2.

The line device X furthermore comprises a control means 15 between the pressure setting device 17 and the connection point A, which is designed as an electromagnetically controllable 3/2-way valve. The control means 15 comprises a magnetic switch 15.1

The reference number 14.5 shows the line between that of the pressure setting device 17 and the control means 15, while the reference number 14.6 shows the line between the control means 15 and the connection point A. The control means 15 is arranged between the connection point A and the pressure setting device 17.

From the control means 15 there is a ventilation line 14.7, which is used for connection to an inlet connection E upstream of the compressor 9 of the turbocharger 7, in particular between the compressor 9 and the air filter 10. Furthermore, as previously mentioned, the line 14.6 goes from the control means 15 to the connection point A from.

The line 14.7 leads, particularly in the case of turbocharged engines, to the inlet connection E upstream of the compressor 9 of the turbocharger 7. The line 14.7 is released by the control means 15 when the pressure after the throttle valve 11 exceeds the pressure upstream of the compressor 9. At the same time, the control means 15 closes the line 14.6 to the connection point A. The line from the pressure setting device 17 via the connection point A into the charge air supply line 21 or the line 14.6 is released by the control means 15 when the pressure upstream of the compressor 9 increases the pressure after the throttle valve 11 exceeds what is particularly the case when idling, low load or thrust of the internal combustion engine or in general of the motor vehicle. The control means 15 expediently closes the line 14.7. Due to the low pressure after the throttle valve 11, a high negative pressure can be generated in the crankcase 1. The pressure in the crankcase 1 is regulated via the pressure setting device 17 to regulate the negative pressure of the crankcase 1 to a predetermined target value. If the pressure after the throttle valve 11 exceeds the target value, the pressure after the throttle valve 11 is minimal in the crankcase 1. If the pressure after the throttle valve 11 exceeds the pressure upstream of the compressor 9, the line 14.7 which is now open has the effect that a pressure in the region of the pressure upstream of the compressor 9 is established in the crankcase 1. The changeover and thus control between the lines before compressor 9 (line 14.7) and after throttle valve 11 (line 14.6) happens via the control means 15. It should be mentioned that the line 14.7 can be omitted in naturally aspirated engines.

The device V further comprises a pressure detection device (pressure sensor) 22 for detecting the charge air pressure downstream of the throttle element 11 in the charge air supply line 21.

The control means 15 can be controlled via an expedient electrical / electronic control device. The control unit preferably corresponds to the engine control unit for controlling the internal combustion engine. This enables the control means 15 to be controllable as a function of the charge air pressure detected by the pressure detection device 22, the rotational speed of the internal combustion engine, the operating mode of the internal combustion engine and / or the current torque of the internal combustion engine. This also makes it possible for the control means 15, depending on the last-mentioned parameters, to have ventilation carried out before the compressor 9 or after the throttle element 11.

However, it is also possible for the pressure detection device 22 to control the control means 15 directly, in particular without interposing a control device, in particular the engine control device. For this purpose, the pressure detection device 22 can be designed as a limit switch which is used to control the magnetic switch 15.1 of the control means 15. Furthermore, an expediently analog voltage or current output of the pressure detection device 22 can be connected to a limit value switch, which is used to control the magnetic switch 15.1 of the control means 15. This enables a cost-effective variant without intervention in the engine control.

The device V further comprises a pressure detection device 23 for detecting the pressure in the crankcase 1. In combination with the pressure detection device 22 for detecting the charge air pressure downstream of the throttle element 11, a diagnosis of the function of the control means 15 and of the pressure setting device 17 can be carried out.

It should be mentioned that the pressure setting device 17 can be designed as a variable pressure controller with a setpoint value, preferably via a voltage or current characteristic curve (s). A pressure setpoint that can be calculated in the control unit can be set. The pressure setpoint can be adjusted in a closed control loop when the pressure detection device 23 is used to detect the pressure in the crankcase 1.

Figure 2 shows a device V according to another embodiment of the invention. The device V initially comprises a crankcase 1 and a line device X. The line device X Figure 2 differs in particular from the line device X Figure 1 that it does not have an electromagnetically actuable control means 15, but rather a pneumatically actuable control means 15 designed as a 3/2-way valve. For this purpose, a pneumatic (vacuum) limit switch 15.1 of the control means 15 is also connected via a pipe and / or hose line 14.8 the charge air supply line 21 connected downstream of the throttle element 11. This also represents a cost-effective variant without intervention in the engine control.

Referring to the embodiments of the Figures 1 and 2 the pressure setting device serves in particular to set a negative pressure of 0.1-500 mbar, preferably more than 100 or 150 mbar, in the crankcase 1 in order to reduce the pressure difference between the crankcase 1 and the combustion chamber 4, which consequently results in a reduced Reverse blow-by and thus leads to a reduced number of emitted particles.

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

The generation of negative pressure of 0.1-500 mbar, preferably more than 100 or 150 mbar, in the crankcase 1 is restricted in particular to the critical operating states of idling, low load and overrun, which can be achieved by the control means 15.

The invention is not limited to the preferred embodiments described above. Rather, a large number of variants and modifications are possible, as defined in the appended claims, which also make use of the inventive concept and therefore fall within the scope of protection. In addition, the invention also claims protection for the subject and the features of the subclaims.

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 valve)

12

crankshaft

13

oil level

14.1

Crankcase ventilation connection or pipe

14.2

Line of oil separator to pressure setting device (pressure regulator)

14.3

Oil return line before check valve

14.4

Oil return line to the oil sump

14.5

Line from pressure setting device to control means

14.6

Line from the control means to the charge air manifold to the throttle element or in the charge air supply line to the throttle element

14.7

Vent line from control means to the inlet connection upstream of the compressor

14.8

Control line from charge air supply line to the control means, in particular for actuating its vacuum limit switch

15

Control means, in particular electromagnetically or pneumatically actuated valve, preferably 3/2-way valve

15.1

Magnetic switch or pneumatic (vacuum) limit switch

16

oil separator

17

Pressure setting device (pressure regulator) for crankcase pressure

18

Check valve in the oil return line

19

Exhaust gas to the exhaust system

20

Charge air to the charge air cooler

21

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

21.1

Charge air from the charge air cooler or charge air flow direction

22

Pressure detection device, pressure sensor, for detecting the charge air pressure downstream of the throttle element in the charge air supply line

23

Pressure detection device, pressure sensor, for detecting the pressure in the crankcase

X

Pipe / ventilation device (ventilation system) for ventilation before the compressor and / or after the throttle element

A

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

e

Inlet connection before compressor

V

Device for an internal combustion engine

Claims (19)

1. An apparatus (V) for an internal combustion engine, in particular for the generation of a vacuum in a crankcase (1) and/or for the ventilation of a crankcase (1), having:

   a crankcase (1),

   at least one combustion chamber (4),

   at least one oil separator (16) which is connected to the crankcase (1), and

   at least one pressure setting device (17) which is configured to set a vacuum in the crankcase (1) during operation, with the result that the pressure difference between the crankcase (1) and the combustion chamber (4) is expediently reduced,

   characterized in that

   the crankcase (1) is connected via a line device (X) at a connector point (A) to a charge air feed line (21) for feeding charge air into the combustion chamber (4), the line device (X) comprising a control means (15), and the control means (15) being configured to limit the setting of the vacuum in the crankcase (1) to the idling, weak load and/or overrun of the internal combustion engine operating states, and the control means (15) comprising a 3/2-way valve.
2. The apparatus (V) according to Claim 1, the line device (X) comprising the oil separator (16) and the pressure setting device (17).
3. The apparatus (V) according to Claim 2, the oil separator (16) being connected to the crankcase (1) via a ventilating element (14.1) and an oil return device (14.3, 14.4), and the oil return device (14.3, 14.4) preferably having a check valve (18).
4. The apparatus (V) according to one of Claims 1 to 3, the line device (X) comprising a control means (15), and the control means (15) being configured for at least one of the following: for controlling the ventilation of the crankcase (1) upstream of a compressor (9) of a turbocharger (7) or to the connector point (A), for preventing a return flow of air into the crankcase (1), and/or for limiting of the operating range of the line device (X) to the connector point (A).
5. The apparatus (V) according to one of Claims 1 to 4, the line device (X) being connected to the charge air feed line (21) downstream of a throttle element (11) of the charge air feed line (21) in the charge air flow direction (21.1).
6. The apparatus (V) according to one of Claims 1 to 5, a ventilating line (14.7) branching off from the control means (15), and the ventilating line (14.7) serving for the connection to an introduction connector (E) upstream of a compressor (9) of a turbocharger (7) in the flow direction.
7. The apparatus (V) according to one of Claims 1 to 6, characterized in that the control means (15) comprises an electromagnetically or pneumatically actuated valve.
8. The apparatus (V) according to one of the preceding claims, characterized in that the apparatus (V) has a pressure detection device (22) for the detection of the charge air pressure downstream of a throttle element (11) in a charge air feed line (21) for feeding charge air into the combustion chamber (4).
9. The apparatus (V) according to one of Claims 1 to 8, characterized in that the apparatus (V) has an electric or electronic control unit for controlling the control means (15), in particular an engine control unit for controlling the internal combustion engine and additionally for controlling the control means (15).
10. The apparatus (V) according to Claim 9, characterized in that the control unit actuates the control means (15) in a manner which is dependent on at least one of the following, and/or permits the control means (15) to carry out a ventilation of the crankcase (1) upstream of a compressor (9) of a turbocharger (7) or to the connector point (A) in a manner which is dependent on at least one of the following:

    - the charge air pressure which is detected by the pressure detection device (22),

    - the rotational speed of the internal combustion engine,

    - the operating type of the internal combustion engine,

    - the current torque of the internal combustion engine.
11. The apparatus (V) according to one of Claims 1 to 8, characterized in that the control means (15) can be actuated via the pressure detection device (22) directly and/or without a control unit being connected in between.
12. The apparatus (V) according to one of the preceding claims, characterized in that the pressure detection device (22) comprises a limit switch, or a voltage or current output of the pressure detection device (22) is connected to a limit switch for actuating the control means (15).
13. The apparatus (V) according to one of the preceding claims, characterized in that the apparatus (V) comprises a pressure detection device (23) for the detection of the pressure in the crankcase (1), with the result that a diagnosis of the function of the control means (15) and/or of the pressure setting device (17) is enabled, preferably in combination with the pressure detection device (22) for the detection of the charge air pressure downstream of a throttle element (11).
14. The apparatus (V) according to one of the preceding claims, characterized in that the pressure setting device (17) is configured as a variable pressure regulator with a setpoint setting, preferably via at least one voltage or current characteristic, and a setpoint value which can be calculated in the control unit can be set, and the setpoint value can be adjusted in a closed regulating circuit with the use of the pressure detection device (23) for the detection of the pressure in the crankcase (1) .
15. The apparatus according to one of Claims 1 to 14, characterized in that a control line (14.8) branches off downstream of the throttle element (11) for the pneumatic actuation of the control means (15) in a manner which is dependent on the charge air pressure downstream of the throttle element (11), preferably via a vacuum limit switch of the control means (15).
16. The apparatus (V) according to one of the preceding claims, the pressure setting device (17) serving to set a vacuum of from 0.1 to 500 mbar, preferably of over 100, 150, 200, 250, 300 or even of over 500 mbar in the crankcase (1), in order to reduce the pressure difference between the crankcase (1) and the combustion chamber (4), which as a consequence expediently leads to a reduced reverse blow-by and therefore to a reduced number of emitted particles.
17. An internal combustion engine, preferably a gas engine or another combustion engine with a spark-ignition combustion process, having an apparatus (V) according to one of the preceding claims.
18. A motor vehicle, preferably a commercial vehicle, having an internal combustion engine according to Claim 17.
19. An operating method for an apparatus (V) having at least one combustion chamber (4), a crankcase (1) and at least one oil separator (16) which is connected to the crankcase (1), configured with an apparatus (V) according to one of Claims 1 to 16, a vacuum being set in the crankcase (1) by means of at least one pressure setting device (17), in order to expediently reduce the pressure difference between the crankcase (1) and the combustion chamber (4).

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