DE102014204576A1 - Detection method and motor vehicle - Google Patents

Abstract

A detection method (30) is claimed for detecting deposits caused by an exhaust gas flow (24) on a turbine (14) arranged in an exhaust line (13) of an engine (11). In an actual value determination (32), an actual value of at least one state variable influenced by the deposits is determined and then evaluated. According to the invention, the actual value is determined (32) in an exhaust gas secondary flow (25) which is taken from the exhaust gas flow (24) and passed in a bypass (19) past the turbine (14). A motor vehicle (10) suitable for carrying out the identification method (30) is also claimed.

Description

The present invention relates to a detection method for detecting deposits caused by an exhaust gas flow on a turbine disposed in an exhaust line of an engine and to a motor vehicle.

In modern internal combustion engines, which are designed for a lean operation and for a rich operation, especially during a short regeneration phase for an exhaust aftertreatment device deposits, in particular wet soot arise. This can stick to components in the exhaust system and impair their function.

The DE 19959870 A1 shows a measuring arrangement and a method for monitoring the operation of a soot filter. In this case, a partial flow of an exhaust gas flow through a, in the flow direction open-porous molded body and it is the temperature of the molded body measured with at least one temperature sensor. The soot filter is a soot sensor having a, in the flow direction open-porous molded body, an electric heating element and a temperature sensor associated. The soot sensor should allow a direct determination of the amount of soot on the soot filter.

DE 10 2009 058 698 A1 discloses a method for determining the efficiency of a particulate filter. An internal combustion engine has for this purpose at least one supply system for the combustion air and at least one exhaust system. The at least one exhaust system has at least one exhaust pipe, in which a first particle filter is arranged and a second particle filter is connected downstream. The second particulate filter is associated with a differential pressure sensor to determine the differential pressure between a location upstream and a location downstream of the second particulate filter.

The DE 10000921 A1 refers to a particulate filter system, in particular for diesel engines, with a particulate filter arranged in the exhaust gas channel and a bypass channel bypassing, opening or opening the particulate filter. A preferably non-regenerable particulate filter is associated with a bypass channel arranged in parallel, which has a bursting plate which can be destroyed by a high exhaust backpressure.

From the EP 1405995 A1 goes out an engine system having an internal combustion engine, an exhaust gas turbocharger whose turbine is arranged in the exhaust pipe of the internal combustion engine and its associated with the turbine compressor in the inlet line of the internal combustion engine. The turbine is set in rotation by the exhaust gases leaving the internal combustion engine. As a result, in turn, the compressor is driven, which causes an increase in the boost pressure in the internal combustion engine. Further, the engine system includes an exhaust gas recirculation pipe whose inlet is disposed upstream of the above-mentioned turbine in the exhaust pipe of the internal combustion engine and the outlet thereof downstream of the aforementioned compressor in the intake pipe of the internal combustion engine. Exhaust gas from the engine exhaust may be returned to the inlet via the exhaust gas recirculation line to improve exhaust and runnability. In addition, the engine system includes an exhaust treatment device disposed in the exhaust gas recirculation line.

The DE 10 2008 014 621 A1 discloses a method for determining the need for multiple wing cleaning procedures in an exhaust gas turbocharger. The method includes the use of sensor data signals to determine if the effort to operate the turbocharger exceeds a predetermined threshold, indicating that at least one wing is contaminated by exhaust soot, the turbocharger then operating at a predetermined speed for a predetermined number of repetitions until the effort to operate the turbocharger is at least equal to or less than a predetermined threshold.

From the DE 10 2004 036 064 A1 is a diagnostic method for detecting errors in the charge pressure control of an internal combustion engine with an exhaust gas turbocharger and a turbocharger upstream mechanical compressor out, which should make it unnecessary to use an air mass sensor and allow further differentiation of the diagnosed errors by location and / or type of error. For a combined turbocharger and compressor operation by means of pressure sensors at least one intake manifold pressure of the internal combustion engine, a pressure between the compressor and a compressor of the turbocharger and a pressure between the compressor of the turbocharger and the internal combustion engine, in particular a throttle valve of the internal combustion engine, and preferably also outside ambient pressure measured. At least a portion of the measured pressures or an air mass flow determined using these pressures is compared with corresponding modeled pressures or with a corresponding model mass flow for leak-free operation, which have been determined for a corresponding operating state.

The present invention has for its object to provide a detection method for Deposits to provide a turbine and a motor vehicle for performing the detection method.

This object is achieved with a recognition method according to claim 1 and a motor vehicle according to claim 6 Advantageous developments of the invention are specified in the subclaims and described in the description.

In the detection method according to the invention for detecting deposits caused by an exhaust gas flow at a turbine arranged in an exhaust line of an engine, an actual value of at least one state variable influenced by the deposits is determined in an actual value determination and subsequently evaluated. According to the invention, the actual value is determined in a secondary exhaust gas flow, which is taken from the exhaust gas flow and passed in a bypass to the turbine.

The exhaust secondary flow has as part of the exhaust gas flow the same composition as the exhaust gas flow. The deposits on the turbine caused by the exhaust gas flow can be assessed with the detection method according to the invention without having to monitor the turbine itself. Turbines are hard-to-reach components, or components where attaching a sensor is difficult or impossible to implement. The present method offers an improvement here. Turbines are affected by the deposits and otherwise only very expensive to investigate for deposits. Being able to use the detection method according to the invention here protects the turbine and increases its efficiency.

In an advantageous embodiment of the detection method according to the invention, a deposition element is acted upon by the secondary exhaust gas flow.

This forces more particles to adhere. A deposit can be detected faster. The recognition process is thus shortened in time. It can be taken earlier countermeasures.

In a further advantageous embodiment of the recognition method according to the invention, a pressure and / or, in the case of a rotatable flow element, a rotational speed and / or a torque of the flow element are determined as a state variable.

These sizes are easily measurable and allow accurate conclusions on the level of deposits. Corresponding sensors are widely used and thus cheap to use.

In a further advantageous embodiment of the detection method according to the invention, the exhaust gas flow is increased as a measure and / or the temperature of the exhaust gas flow is increased and / or it is heated by means of a heating element.

With these measures, the deposits can be eliminated quickly. An increased exhaust gas flow has an increased flushing effect. This allows heavier particles or an increased number of particles to be transported. Increasing the temperature causes the particles to dry. The particles thus lose weight and stickiness.

For carrying out the recognition method according to the invention, a motor vehicle suitable for this purpose is additionally provided. The motor vehicle includes an engine, an exhaust system and an evaluation unit. In the exhaust line a turbine is arranged. According to the invention, the exhaust gas line has a bypass which is suitable for diverting a portion of an exhaust gas flow resulting from the operation of the engine as an exhaust gas side stream upstream of the turbine and for returning it to the exhaust gas flow downstream of the turbine. At least one sensor connected to an evaluation unit is arranged in the bypass for determining an actual value of a state variable.

With the motor vehicle according to the invention, it is possible to carry out the recognition method according to the invention.

The turbine is in an advantageous embodiment of the exhaust line according to the invention, the turbine of an exhaust gas turbocharger.

The ability to use the detection method according to the invention in a turbine of an exhaust gas turbocharger has a positive effect on the engine of the motor vehicle, the boost pressure of which can be provided more efficiently with a cleaner turbine.

In a further advantageous embodiment of the motor vehicle according to the invention, a deposition element is arranged in the bypass. The deposition element may be both a flow element and a filter.

The deposition element enhances the deposition and thereby the effects associated with the deposition. Deposits can thus be detected faster in the detection method according to the invention. In addition, with the deposit element is given the opportunity to better adjust the situation of the turbine by the Deposition element has an at least similar shape and / or kinematics. Thus, with the flow element, for example, a turbine situation can be readjusted very well by the flow element itself being a turbine.

In a further advantageous embodiment of the motor vehicle according to the invention, the exhaust gas system has a heating element.

This makes it possible, regardless of motor measures, to increase the temperature and to remove moisture from the deposits.

Embodiments of the invention will be explained in more detail with reference to the drawings and the description below.

1 schematically shows a motor vehicle according to the invention with an exhaust system.

2 shows a bypass of the exhaust line.

3 shows a further embodiment of the bypass.

4 shows a detection method according to the invention in a diagram.

In the 1 is an example of a motor vehicle according to the invention 10 shown schematically. The car 10 includes a motor 11 and an exhaust system 13 , The motor 11 Here is an internal combustion engine 11 , which is designed to be operated both in a lean operation and in a rich operation. An operation of the engine 11 causes an exhaust gas flow 24 passing through the exhaust system 13 is directed into the environment of the motor vehicle. The exhaust gas flow 24 of the motor 11 has particles in the exhaust stream 24 be carried along. The particles are in particular soot particles, which are particular after brief fat operation of the engine 11 as moist soot can attach to components in the exhaust system.

In the embodiment shown, the motor vehicle has 10 also via a fresh gas train 12 that's the engine 11 supplied with fresh supply air for the combustion process. The fresh gas train 12 is here with a fresh air filter 15 Mistake.

The Indian 1 shown exhaust system 13 has a first exhaust aftertreatment device 16 , a second exhaust aftertreatment device 17 and a silencer 18 on. The exhaust aftertreatment devices 16 . 17 may be, for example, storage catalysts, oxidation catalysts or particle filters. The exhaust aftertreatment devices 16 . 17 correspond to the state of the art.

The exhaust system 13 has a bypass 19 on. The bypass 19 bridges one in the exhaust system 13 arranged turbine 14 to which the exhaust stream 24 acts. An entrance of the bypass 19 is upstream of the turbine 14 arranged and an exit of the bypass 19 is downstream of the turbine 14 arranged. Through the bypass 19 is part of the exhaust gas flow 24 be conducted. This part is here as exhaust secondary flow 25 designated. By the arrangement of the bypass 19 becomes the exhaust side stream 25 the exhaust gas flow 24 upstream of the turbine 14 taken. Downstream of the turbine 14 becomes the exhaust side stream 25 the exhaust gas flow 24 fed.

The turbine 14 is in particular a part of an exhaust gas turbocharger 26 and formed in the manner of a compressor in the fresh gas line 12 drive. In this way it is in the 1 shown. It is also conceivable that the turbine 14 is designed to drive a generator for generating electrical energy.

In the exhaust system 13 can continue a heating element 27 be arranged. The heating element 27 is in particular electrically operated. The heating element 27 is designed in the way deposits on the turbine 14 to heat up. The deposits can thereby dry better and lose their stickiness. In the 1 is the heating element 27 within the exhaust system 13 positioned. It is also conceivable the heating element outside of the exhaust system 13 to arrange.

The bypass 19 of the exhaust system 13 is available in two different versions 2 and 3 outlined as an example. In the bypass 19 is at least one sensor 21 arranged to detect a state variable. The value of the state variable is inventively dependent on the amount of particle deposits in the bypass 19 , The at least one sensor 21 is with an evaluation unit 22 data-connected or connectable.

The bypass 19 may additionally have a deposit element. At this deposition element, the particles, in particular the Feuchtruß store more than on an inner wall of the bypass 19 , The effect on the state variable is thereby enhanced.

In the 2 is a possible execution of the bypass 19 exemplified. In this, the deposition element as a filter element 20 educated. In the embodiment shown is a sensor 21 upstream and a sensor 21 downstream of the filter element 20 positioned. The sensors 21 are here pressure sensors 21 , The filter element 20 is formed in the way particles from the exhaust gas side stream 25 take. With increased Deposition increases the pressure difference in front of and behind the filter element.

In the 3 is another version of the bypass 19 shown in the deposition element as a flow element 23 is trained. The flow element 23 is rotatably mounted and formed in such a way that it from the exhaust gas side stream 25 can be rotated. The sensor 21 Here is a speed sensor 21 and / or a torque sensor 21 and / or a pressure sensor 21 , With increase of deposits on the flow element 23 they change with the sensor 21 determinable state variables. Thus, with increasing deposition level, the speed and torque of the flow element decrease 23 , In addition, with increasing deposition, the pressure difference increases in front of and behind the flow element 23 , The flow element 23 is in particular a turbine.

The secondary exhaust gas flow 25 in the bypass 19 points as part of the exhaust stream 24 the same composition as the exhaust stream 24 on. State variables that are in the bypass 19 Thus, information about the deposition situation on the turbine can be determined 14 itself. This circumstance makes the recognition method according to the invention 30 for detecting the through the exhaust gas flow 24 caused deposits on the exhaust system 13 of the motor 11 arranged turbine 14 advantage.

In the 4 is an example of a recognition method according to the invention 30 in a flow chart of startup 31 until the end 35 shown. In the recognition process 30 is inventively in an actual value determination 32 an actual value of at least one state variable determined, which is influenced by the deposits. Subsequently, this value is evaluated, thereby determining the deposition level.

The evaluation itself can be carried out by known measures, for example by a comparison of values 33 , in which the actual value is compared with a stored setpoint. The setpoint can also be taken from a stored map, which parameter of the engine 11 and / or the motor vehicle 10 taken into account. In the case of a predefined deviation of the actual value from the nominal value, a measure can be taken 34 to reduce deposits.

After a determination of deposits, are different measures 34 conceivable for the degradation of the deposits.

For example, the exhaust gas flow 24 be increased by an exhaust gas recirculation flow is reduced or the speed of the engine 11 is increased, for example by means of an alternator. The increased exhaust gas flow 24 has an increased flushing effect. Even heavier particles are washed away by the increased exhaust gas flow. An increased exhaust gas flow 24 also favors the drying of wet particles.

Furthermore, the temperature of the exhaust gas flow 24 be increased by internal engine measures, such as a richer engine operation. It is also conceivable the temperature by means of the heating element 27 to increase. The elevated temperature promotes the breakdown of soot deposits. With an increased temperature, it is possible in particular to better remove moisture from moist soot. The soot then tends less to stick and better with the exhaust gas flow 23 be transported away.

Will the recognition method of the invention 30 applied to the deposits on the turbine 14 the exhaust gas turbocharger 26 to determine is a support of the turbine 14 conceivable by means of an auxiliary motor. The disturbing influences on the operation of the turbine 14 could be compensated.

LIST OF REFERENCE NUMBERS

10

 motor vehicle

11

 engine

12

 Fresh gas line

13

 exhaust gas line

14

 turbine

15

 Fresh air filter

16

 First exhaust aftertreatment device

17

 Second exhaust aftertreatment device

18

 silencer

19

 bypass

20

 filter element

21

 sensor

22

 evaluation

23

 flow element

24

 exhaust gas flow

25

 Exhaust bypass

26

 turbocharger

27

 heating element

30

 detection methods

31

 begin

32

 actual-value

33

 value comparison

34

 measure

35

 The End

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19959870 A1 [0003]
• DE 102009058698 A1 [0004]
• DE 10000921 A1 [0005]
• EP 1405995 A1 [0006]
• DE 102008014621 A1 [0007]
• DE 102004036064 A1 [0008]

Claims (11)

Detection method ( 30 ) for detecting by an exhaust gas flow ( 24 ) caused deposits on a in an exhaust line ( 13 ) of an engine ( 11 ) arranged turbine ( 14 ), whereby in an actual value determination ( 32 ) an actual value of at least one of the deposits influenced state variable is determined and then evaluated, characterized in that the actual value determination ( 32 ) in a secondary exhaust gas stream ( 25 ), which is the exhaust gas flow ( 24 ) and in a bypass ( 19 ) on the turbine ( 14 ) is passed by. Detection method ( 30 ) according to claim 1, wherein with the secondary exhaust gas flow ( 25 ) is acted upon by a deposition element. Detection method ( 30 ) according to claim 1 or 2, wherein a state variable is a pressure and / or a rotatable flow element ( 23 ) a speed and / or a torque of the flow element ( 23 ) be determined. Detection method ( 30 ) according to one of the preceding claims, wherein in the determination of deposits a measure ( 34 ) is initiated to reduce the deposits. Detection method ( 30 ) according to claim 4, wherein as a measure ( 34 ) the exhaust gas flow ( 24 ) and / or the temperature of the exhaust gas flow ( 24 ) is increased and / or heated by means of heating elements. Motor vehicle ( 10 ) for carrying out a recognition method ( 30 ) according to one of the preceding claims, with a motor ( 11 ), an exhaust gas line ( 13 ) and an evaluation unit ( 22 ), wherein in the exhaust line ( 13 ) a turbine ( 14 ), wherein the exhaust gas line ( 13 ) a bypass ( 19 ), which is suitable for part of a motor ( 11 ) resulting exhaust stream ( 24 ) as a secondary exhaust gas flow ( 25 ) upstream of the turbine ( 14 ) and downstream of the turbine ( 14 ) the exhaust gas flow ( 24 ), whereby in the bypass ( 19 ) at least one sensor connected to the evaluation unit 21 is arranged to determine an actual value of a state variable. Motor vehicle ( 10 ) according to claim 6, wherein the turbine ( 14 ) the turbine ( 14 ) of an exhaust gas turbocharger ( 26 ). Motor vehicle ( 10 ) according to claim 6 or 7, wherein in the bypass ( 19 ) A deposition element is arranged. Motor vehicle ( 10 ) according to claim 8, wherein the deposition element is a flow element ( 23 ). Motor vehicle ( 10 ) according to claim 8, wherein the deposition element is a filter element ( 20 ). Motor vehicle ( 10 ) according to one of claims 6 to 10, wherein the exhaust gas line ( 13 ) a heating element ( 27 ) having.

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