DE102015007154A1 - 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) in communication with the crankcase (1) and at least one pressure adjusting device (17), 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 burnt 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, eg. B. a motor vehicle engine.

It is possible for the crankcase to be connected to a charge air supply line for supplying charge air into the combustion chamber via a line device (eg venting device, line, line system, etc.) at a connection point. 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 the oil separator and / or the pressure adjusting means. 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 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 conduit device may in particular comprise a control means.

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

It is also possible that the control means for controlling, in particular for switching between, the ventilation in front of a compressor of a turbocharger or to the connection point serves (connection point: charge air supply line and conduit means, in particular downstream of the throttle element).

The control means is preferably a valve, in particular a 3/2-way valve. The control means may in particular be designed to be electromagnetically or pneumatically controllable.

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

It is possible that the device comprises a pressure detection device, for. B. has a pressure sensor for detecting the charge air pressure downstream of the throttle element in the charge air supply 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 unit is preferably the engine control unit for controlling the internal combustion engine. The control means can for this purpose z. B. are connected directly to an electrical output of the engine control unit.

It is therefore possible for the engine control unit to be used for controlling the internal combustion engine in addition to controlling the control means.

It is possible for the controller to control the control means in response to at least one of the following: a charge air pressure detected by the pressure sensing means, a speed of the internal combustion engine, the operating mode of the internal combustion engine (eg, 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.

It is likewise possible for the control device to allow the control means to carry out a vent in front of a compressor of a turbocharger or after the throttle element or in the charge air supply line 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 the internal combustion engine (eg 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.

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

Furthermore, there is 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 breakage and / or short circuit.

It is possible that the device comprises a pressure detecting 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 thus a diagnosis of the function of the control means and / or the pressure setting device is possible.

The pressure adjustment can z. B. as a variable pressure regulator with setpoint specification, preferably via voltage or current characteristic (s), executed. A calculable in the control unit pressure setpoint is suitably adjustable, the setpoint with simultaneous use of the pressure detecting means for detecting the pressure in the crankcase in a closed loop is einregelbar.

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

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

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

The pressure detection device can be designed in particular as a limit value switch, the z. B. directly drives 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 to control a magnetic switch of the control means.

It is possible that downstream of the throttle element, a control line (eg pipe and / or hose) goes off for the 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 electric / electronic engine 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 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 that a vent line branches off from the control means and the vent line serves for connection to an introduction port in front 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 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 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 19 indicates exhaust gas to the exhaust system. The reference number 20 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 21.1 behind a throttle 11 a charge air supply line 21 with 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 number 21.1 indicates the charge air from the charge air cooler, not shown, or the flow direction of the charge air in the charge air supply 21 ,

The conduit means X comprises an oil separator 16 and a pressure adjusting device 17 for the crankcase pressure (eg a pressure regulator). The oil separator 16 is via a crankcase ventilation port 14.1 on the one hand and via an oil return line 14.3 and 14.4 on the other hand 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 is over a line 14.2 with the pressure adjustment device 17 connected.

The conduit means X further comprises between the pressure adjusting means 17 and the connection point A is a control means 15 , which is designed as an electromagnetically controllable 3/2-way valve. The control means 15 includes a magnetic switch 15.1 The reference number 14.5 shows the line between the pressure adjustment 17 and the control means 15 while the reference number 14.6 the line between the control means 15 and the junction A shows. The control means 15 is between the junction A and the pressure adjusting device 17 arranged.

From the control means 15 go a vent line 14.7 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 , Further, as previously mentioned, the control means proceeds 15 The administration 14.6 to junction A from.

The administration 14.7 leads in particular in turbocharged engines to the inlet port E in front of the compressor 9 of the turbocharger 7 , The administration 14.7 is by the control means 15 released when the pressure after the throttle 11 the pressure in front of the compressor 9 exceeds. At the same time closes the control means 15 The administration 14.6 to junction A. The line from the pressure regulator 17 via connection point A into the charge air supply line 21 or the line 14.6 is by the control means 15 released 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. This closes the control means 15 appropriate the line 14.7 , Due to the low pressure after the throttle 11 can be 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 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 14.7 that is in the crankcase 1 a pressure in the range of the pressure in front of the compressor 9 established. The switching and thus control between the lines before compressor 9 (Management 14.7 ) and throttle 11 (Management 14.6 ) is done via the control means 15 , It should be mentioned that in naturally aspirated engines the line 14.7 can be omitted.

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 is controlled by a convenient electrical / electronic control unit. The control unit preferably corresponds to the engine control unit for controlling the internal combustion engine. This will allow the control means 15 as a function of the pressure detection device 22 detected charge air pressure, the speed of the internal combustion engine, the operating mode of the internal combustion engine and / or the current torque of the internal combustion engine is controllable. This also makes possible that the control means 15 depending on the latter parameters, a vent in front of the compressor 9 or after the throttle element 11 can run.

However, it is also possible that the pressure detection device 22 the control means 15 directly, in particular without the interposition of a control device, in particular the engine control unit, controls. For this purpose, the pressure detection device 22 be designed as a limit switch, which is used to drive the magnetic switch 15.1 of the tax money 15 serves. Furthermore, a suitably analog voltage or current output of the pressure detection device 22 be connected to a limit switch, which is used to drive the magnetic switch 15.1 of the tax money 15 serves. This allows 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 , This can be used 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 the pressure adjusting device 17 be executed.

It should be mentioned that the pressure adjustment 17 as a variable pressure regulator with setpoint specification, preferably via voltage or current characteristic (s), can be executed. A pressure setpoint that can be calculated in the control unit is adjustable. The pressure setpoint is when using the pressure sensing device 23 for detecting the pressure in the crankcase 1 einregelbar in a closed loop.

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

The device V initially comprises a crankcase 1 and a conduit X.

The line device X the 2 differs in particular characterized by the line device X the 1 in that it does not have an electromagnetically actuable control means 15 but a pneumatically actuated, designed as a 3/2-way valve control means 15 , For this purpose, a pneumatic (vacuum) limit switch 15.1 of the tax money 15 via a pipe and / or hose line 14.8 with the charge air supply line 21 downstream of the throttle element 11 connected. This also represents a cost-effective variant without intervention in the engine control.

With reference to the embodiments of the 1 and 2 the pressure adjustment device is used in particular 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 states idle, light load and thrust, which is controlled by the control means 15 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

Line from Druckeinstelleinrichtung to the control means

14.6

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

14.7

Bleed line from control means to the inlet port before compressor

14.8

Control line of charge air supply to the control means, in particular for operating the vacuum limit switch

15

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

15.1

Magnetic switch or pneumatic (vacuum) limit switch

16

oil separator

17

Pressure adjusting device (pressure regulator) for crankcase pressure

18

Check valve in oil return line

19

Exhaust gas to the exhaust system

20

Charge air to the intercooler

21

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

21.1

Charge air from the intercooler or charge air flow direction

22

Pressure detecting means, pressure sensor, for detecting the charge air pressure downstream of the throttle element in the charge air supply

23

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

X

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

A

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

e

Inlet connection before compressor

V

Device for an internal combustion engine

Claims (21)

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 ( 21 ) for supplying charge air into the combustion chamber ( 4 ) connected is. Device (V) according to claim 2, wherein the conduit means (X) comprise the oil separator ( 16 ) and the pressure adjustment device ( 17 ). Device (V) according to claim 3, wherein the oil separator ( 16 ) 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 ) having. Device (V) according to one of claims 2 to 4, wherein the conduit means (X) comprises a control means (10). 15 ) and the control means ( 15 ) is carried out for at least one of the following: for controlling the ventilation of the crankcase ( 1 ) in front of a compressor ( 9 ) of a turbocharger ( 7 ) or to the connection point (A), 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) in the charge air flow direction ( 21.1 ) behind a throttle element ( 11 ) of the charge air supply line ( 21 ) with the charge air supply line ( 21 ) connected is. Device (V) according to one of claims 5 to 7, wherein the control means (V) 15 ) a vent line ( 14.7 ) branches off and the vent line ( 14.7 ) 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 one of claims 5 to 7, characterized in that the control means ( 15 ) comprises a 3/2-way valve. Device (V) according to one of claims 5 to 8, characterized in that the control means ( 15 ) comprises an electromagnetically or pneumatically actuated valve. Device (V) according to one of the preceding claims, characterized in that the device (V) comprises a pressure detection device ( 22 ) for detecting the charge air pressure downstream of a throttle element ( 11 ) in a charge air supply line ( 21 ) for supplying charge air into the combustion chamber ( 4 ) having. Device (V) according to one of claims 5 to 10, characterized in that the device (V) is an electrical or electronic control device for controlling the control means ( 15 ), in particular an engine control unit for controlling the internal combustion engine and in addition to controlling the control means ( 15 ). Device (V) according to claim 11, characterized in that the control device controls ( 15 ) in Is dependent on at least one of the following and / or the control means ( 15 ) depending on at least one of the following a venting of the crankcase ( 1 ) in front of a compressor ( 9 ) of a turbocharger ( 7 ) or to the connection point (A): - of the pressure detection device ( 22 ) detected charge air pressure - the speed of the internal combustion engine - the operating mode of the internal combustion engine - the current torque of the internal combustion engine. Device (V) according to one of claims 1 to 10, characterized in that the control means ( 15 ) via the pressure detection device ( 22 ) can be controlled directly and / or without the interposition of a control device. Device (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 ) with a limit switch for driving the control means ( 15 ) connected is. Device (V) according to one of the preceding claims, characterized in that the device (V) comprises a pressure detection device ( 23 ) for detecting the pressure in the crankcase ( 1 ), so that preferably in combination with the pressure detection device ( 22 ) for detecting the charge air pressure downstream of a throttle element ( 11 ) a diagnosis of the function of the control means ( 15 ) and / or the pressure adjustment device ( 17 ). Device (V) according to one of the preceding claims, characterized in that the pressure adjustment device ( 17 ) is designed as a variable pressure regulator with setpoint specification, preferably via at least one voltage or current characteristic, and a setpoint value which can be calculated in the control unit is adjustable and the setpoint value is determined using the pressure detection device ( 23 ) for detecting the pressure in the crankcase ( 1 ) is einregelbar in a closed loop. Device according to one of claims 5 to 16, characterized in that downstream of the throttle element ( 11 ) a control line ( 14.8 ) for the pneumatic actuation of the control means ( 15 ) as a function of the charge air pressure downstream of the throttle element ( 11 ), preferably via a vacuum limit switch of the control means ( 15 ). Device (V) according to one of the preceding claims, wherein the pressure adjustment device ( 17 ) 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 19. 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 18, 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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