KR102422973B1 - Method for heating and regenerating a particulate filter in an exhaust gas of an otto engine - Google Patents

Abstract

The present invention relates to a method for heating and regeneration of a particulate filter (26) arranged downstream of a catalytic converter (30) in an exhaust gas stream of an Otto engine (10), said Otto engine (30) and a device (50) for supplying secondary air to the exhaust gas stream between the particulate filter (26). The method is characterized in that the transverse sensitivity of the lambda sensor arranged between the catalytic converter and the particulate filter to oxygen, which is another exhaust gas constituent, is compensated. Still other independent claims relate to an Otto engine, a computer program product and a computer readable medium.

Description

Method for heating and regenerating particulate filter in exhaust gas of auto engine

The present invention relates to a method for heating and regenerating a particulate filter arranged downstream of a catalytic converter in an exhaust gas stream of an Otto engine, according to the preamble of claim 1 , wherein the Otto engine is between the catalytic converter and the particulate filter. a device for supplying secondary air to the exhaust gas stream of

The invention also relates to an Otto engine according to the preamble of claim 10 comprising said device, and to a computer program product and a computer readable medium.

It is assumed that the method and the Otto engine are known per se. In recent engine control systems, a lambda sensor is used for detection of oxygen concentration in exhaust gas and for lambda control of an Otto engine. In this case, a wideband lambda sensor and a discrete-level lambda sensor are used.

In general, broadband lambda sensors are used where rich or lean lambda values must be accurately measured, or where measuring with limited accuracy within a range near "lambda = 1" is sufficient. The broadband lambda sensor enables the measurement of air ratio lambda over a wide air ratio range. For a discrete level lambda sensor, the signal fluctuates abruptly at "lambda = 1", so that small lambda fluctuations in this range cause large signal fluctuations. Discrete level lambda sensors are therefore used where the exhaust gas lambda must be measured with high accuracy in the range near "lambda = 1" (see Bosch, Technical Manual for Automotive, 23rd ed., p. 524).

Typical fields of application of a wideband lambda sensor are lambda control based on a signal from a lambda sensor disposed upstream of a catalytic converter, and balancing the inlet and outlet of oxygen in diagnostics of the catalytic converter. Typical applications of discrete level lambda sensors are highly accurate "lambda = 1" control in configurations where the discrete level lambda sensor is placed downstream of the catalytic converter, and breakthrough of rich or lean exhaust gases during diagnostics of the catalytic converter. ) is the detection of

A typical exhaust system of a gasoline powered Otto engine (eg SULEV) for the current stringent emission and onboard diagnostic requirements includes a broadband lambda sensor; a first three-way catalytic converter disposed downstream of the lambda sensor; a discrete level lambda sensor disposed downstream of the first three-way catalytic converter; and a second unmonitored three-way catalytic converter disposed downstream of the discrete level lambda sensor. It is foreseeable that even more stringent emission and diagnostic requirements in the future will require an exhaust gas system in which the secondary catalytic converter is likewise monitored as well as the particulate concentration in the tail pipe emission is limited. The second three-way catalytic converter must therefore be combined with a particulate filter or replaced with a coated particulate filter, also referred to as a four-way catalytic converter.

a first lambda sensor (broadband) upstream of the three-way catalytic converter, in particular in the exhaust gas stream of an Otto engine, for the fulfillment of future emission and diagnostic requirements; a second lambda sensor (broadband or discrete level) downstream of the three-way catalytic converter; a particulate filter, preferably a catalyst coated particulate filter; An exhaust gas system is contemplated comprising a third lambda sensor (discrete level) disposed downstream of the particulate filter. Between the catalytic converter and the particulate filter, there is additionally provided a secondary air supply which can be implemented upstream or downstream of the second lambda sensor. The signal of the second lambda sensor in the system should be used, in particular, for optimal operation of the preferably coated particulate filter. Optimal operation of the preferably coated particulate filter is characterized by rapid attainment of operating temperature and rapid regeneration.

Optimal operation presupposes that there is a clear correlation between the lambda at the mounting position of the second lambda sensor and the signal of the second lambda sensor, since otherwise the air ratio lambda based on the signal This is because the control accuracy is not sufficient and excessively high emissions or damage to the particulate filter may occur. The signal of the second lambda sensor is generally a different sensitivity of the second lambda sensor to oxygen and the second lambda to various exhaust gas components (eg CO, CO ₂ , H ₂ , H ₂ O, HC, NO _x ). The above prerequisite is for a discrete level lambda sensor as well as for a wideband lambda sensor, since it is affected by the transverse sensitivity of the sensor and the exhaust gas composition can vary under different operating conditions even if the exhaust gas lambda is the same. is not usually met.

The invention is distinguished from the prior art mentioned in the introduction by the features of the characterizing part of claim 1 with respect to its method aspects and by the features of the characterizing part of claim 10 with respect to its apparatus aspects. The invention in relation to a computer program product has the features of claim 11 , and in connection with a computer program product the invention has the features of claim 12 .

Accordingly, with respect to method aspects, the Otto engine and the apparatus for supplying secondary air, for heating of the particulate filter, have an air ratio lambda representing the first excess fuel in the exhaust atmosphere therein as time averaged at the outlet of the catalytic converter. the first value is adjusted and is driven to adjust a second value of the air ratio lambda corresponding to the stoichiometric composition of the exhaust gas atmosphere therein as time averaged at the inlet of the particulate filter; The device for the auto engine and the secondary air supply is also arranged in the exhaust gas flow between the catalytic converter and the particulate filter to achieve a predetermined value of the air ratio lambda between the catalytic converter and the particulate filter, for regeneration of the particulate filter. output signals of a lambda sensor sensing oxygen as a constituent are detected and a concentration of one or more other exhaust gas constituents is measured; The value of the air ratio lambda is determined according to the detected output signals and further according to the concentration of one or more other exhaust gas components, which are taken into account in the control of the Otto engine and/or the apparatus.

Through the above features, in the case of an exhaust gas system in which secondary air supply is implemented between the first catalytic converter and the coated particulate filter, a signal from a lambda sensor mounted between the first catalytic converter and the coated particulate filter is also supplied, , this signal allows for optimal operation of the particulate filter irrespective of the exhaust gas composition.

By correcting the output signal of the lambda sensor arranged between the catalytic converter and the coated particulate filter according to the invention according to the invention, a clear correlation is established between the sensor signal and the exhaust gas lambda at the sensor position, irrespective of the current exhaust gas composition, in particular The coated particulate filter can operate optimally with respect to the rapid attainment of its operating temperature and with respect to the required regeneration over time, especially with an active secondary air supply.

A preferred embodiment is that the device for supplying the Otto engine and the secondary air, for heating of the particulate filter, at the outlet of the catalytic converter, in the exhaust gas atmosphere therein, at the time averaged time, is at least a second less than the first excess fuel. a third value of the air ratio lambda representing the excess fuel or stoichiometric value is adjusted, and a fourth value of the air ratio lambda corresponding to the excess air in the exhaust atmosphere therein at the inlet of the particulate filter is adjusted, between the catalytic converter and the particulate filter is driven such that output signals of a lambda sensor disposed within the exhaust gas stream of the exhaust gas stream for sensing oxygen as an exhaust gas component are detected and a concentration of one or more other exhaust gas components is measured; It is characterized in that the determination of the air ratio lambda is carried out according to the detected output signals and further according to the concentration of one or more other exhaust gas constituents. The determination is preferably carried out so that the influence of the concentration of another exhaust gas component on the output signal of the lambda sensor in the determination of the air ratio lambda is corrected, ie at least partially excluded.

Another preferred embodiment is characterized in that the concentration of one or more further exhaust gas constituents is modeled from measurement parameters provided in the control unit of the Otto engine.

By taking into account the concentration of one or more other exhaust gas constituents at the sensor location, the accuracy of the lambda value determined from the output signal of the lambda sensor is increased. The quality of the lambda control and other functions, in particular for heating and regeneration of the particulate filter based on the measured lambda of the second lambda sensor, is improved. Emissions of harmful substances are reduced, and damage to the particulate filter due to overheating is prevented.

The method of the present invention can be applied not only for a broadband lambda sensor provided between two catalytic converters, but also for a relatively more cost-effective discrete level lambda sensor.

In the case of an exhaust gas system of the type mentioned in the introduction, in which the secondary air supply is carried out downstream of the second lambda sensor and upstream of the coated particulate filter, the first and third values account for the fluctuations in the combustion chamber lambda of the Otto engine. It is preferable to adjust through

In the case of the exhaust gas system, it is also preferred that the second and fourth values are adjusted through variations in the supply of secondary air to the exhaust gas stream.

Further, in the case of the exhaust gas system, the concentrations of hydrogen and carbon monoxide are measured as concentrations of other exhaust gas constituents, and the ratio of the hydrogen concentration to the carbon monoxide concentration varying with time when lambda at the outlet of the catalytic converter is rich It is desirable that the different lateral sensitivities of the lambda sensor for hydrogen and carbon monoxide are taken into account (effect 1).

In the case of an exhaust gas system of the type mentioned in the introduction, in which the secondary air supply takes place upstream of the second lambda sensor and downstream of the first catalytic converter, the adjustment of the first value and the third value is the catalytic converter and the lambda sensor It is preferred that when the supply of secondary air is carried out between the combustion chamber lambda and the mutually matched adjustment of the secondary air supply.

It is also advantageous for said exhaust gas systems that the second value and the fourth value are adjusted via a change in the supply of secondary air to the exhaust gas stream.

Also, in the case of the exhaust gas systems, the concentrations of hydrogen and carbon monoxide as concentrations of other exhaust gas constituents are measured; When the lambda at the outlet of the catalytic converter is rich, the time-varying ratio of hydrogen concentration to carbon monoxide concentration and the different lateral sensitivities of the lambda sensor to hydrogen and carbon monoxide are taken into account (effect 1); In addition, it is desirable to consider the lateral sensitivity of the lambda sensor to oxygen and the precatalysis of hydrogen and oxygen carried out in the lambda sensor (effect 2).

Other advantages are set forth in the following detailed description and accompanying drawings.

It is apparent that the features of the present invention mentioned above and further described below can be used not only in each specified combination, but also in other combinations or alone, without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention is shown in the drawings and is explained in more detail in the description that follows. In this case, the same reference numerals in different drawings respectively indicate identical or at least functionally comparable elements. Each of the drawings is schematically illustrated.

1 is a view showing an Otto engine having a first exhaust gas system.
2 is a view showing an Otto engine having a second exhaust gas system.
3 is a diagram showing a flowchart as an embodiment of a method according to the present invention;

Specifically, FIG. 1 shows an auto engine 10 with an air supply system 12 , a first exhaust gas system 14.1 , and a control device 16 . In the air supply system 12 are located an air mass sensor 18 and a throttle valve 19 arranged downstream of the air mass sensor 18 . Air flowing into the Otto engine 10 through the air supply system 12 is mixed with gasoline in the combustion chamber 20 of the Otto engine 10 , and this gasoline is fed into the combustion chamber 20 through the injection valve 22 . It is injected directly or upstream of the intake valve of the combustion chamber. The combustion chamber filling fuel thus obtained is ignited and burned by an ignition device 24 , for example a spark plug. The rotation angle sensor 25 detects the rotation angle of the shaft of the Otto engine 10, thereby causing the control device 16 to initiate ignition at a predetermined angular position of the shaft. The driver demand sensor 38 detects the accelerator pedal position and thus the driver's torque demand, and transmits a signal indicative of the torque demand to the control device 16 .

The control device 16 generates input signals (some of these input signals other than those mentioned only by way of example) and, in particular, a triggering signal for the actuator of the Otto engine, which causes the Otto engine to generate the required torque. to form Exhaust gas generated due to combustion is discharged through the first exhaust gas system 14.1. The control device 16 comprises a computer readable medium 16.1 on which a computer program product 16.2 according to the invention, ie comprising the subject matter of claim 10, in machine readable form is stored, for example a memory chip.

The first exhaust gas system 14.1 comprises a three-way catalytic converter 30 and a gasoline particulate filter 26 arranged downstream of the three-way catalytic converter 30 in the exhaust gas stream. The gasoline particulate filter 26 has an internal honeycomb structure made of a porous filter material, which is flowed through by the exhaust gas 28 and filters particulates contained in the exhaust gas 28 .

This particulate filter is based on a particulate filter having a filter material that is catalytically coated to have the effect of a three-way catalytic converter in addition to the particulate filter effect. Three-way catalytic converters are known to convert three exhaust gas components in three reaction pathways: nitrogen oxides, hydrocarbons and carbon monoxide. The particulate filter effect is the fourth pathway, which is the basis for the designation of a four-way catalytic converter. If a particulate filter is mentioned below, this means not only a particulate filter having a catalytically coated filter material, but also a particulate filter not provided with such a coating.

The particulate capture of the particulate filter 26 raises the flow resistance to the exhaust gas 28 , thus raising the differential pressure set for the gasoline particulate filter 26 . The differential pressure is measured, for example, by the differential pressure sensor 29 , and an output signal thereof is transmitted to the control device, or the differential pressure is calculated by a calculation model from information (measured values and/or control variables) existing in the control device. Based on the known exhaust gas mass flow and differential pressure from the control device 16, the flow resistance is derived either by calculation or by accessing the characteristic curve. Upstream of the three-way catalytic converter 30 , a front lambda sensor 32 exposed to exhaust gas is disposed immediately before the three-way catalytic converter 30 . Downstream of the particulate filter 26, immediately after the particulate filter 26, a rear lambda sensor 34 similarly exposed to exhaust gas is disposed. The front lambda sensor 32 is preferably a broadband lambda sensor that enables the measurement of the air ratio lambda over a wide air ratio region. The rear lambda sensor 34 is preferably a so-called discrete-level lambda sensor capable of measuring the air ratio lambda = 1 very accurately because the signal of the lambda sensor changes rapidly (see Bosch, Technical Manual for Motor Vehicles, 23rd ed., p. 524). .

The device 50 for the secondary air supply, for example a secondary air pump, controlled by the control device 16 , is such that the Otto engine is operated with excess air which is unfavorable for the conversion of pollutants in the first catalytic converter 30 . To provide sufficient oxygen in the air to rapidly heat the particulate filter 26 to a ready-to-operate state (e.g., the light off temperature of the catalyst coating) without the need, and to provide effective regeneration of the particulate filter; It is designed and arranged to introduce air between the catalytic converter 30 and the particulate filter 26 into the first exhaust gas system 14.1 . The control unit 16 includes the air mass sensor 18 , the rotation angle sensor 25 , the differential pressure sensor 29 , the front lambda sensor 32 , the rear lambda sensor 34 , and optionally the temperature of the particulate filter present. processing the signal from the temperature sensor 36 for detecting initiation of ignition via the ignition device 24; injection of fuel through an injection valve (22); Triggering of the secondary air pump 50; generates a triggering signal for. Optionally or additionally, the control device 16 also processes signals from other sensors or additional sensors for triggering of the actuators shown or for triggering additional actuators or other actuators.

FIG. 2 shows the device of FIG. 1 with a second exhaust gas system 14.2 . The two exhaust gas systems 14.1 and 14.2, the second lambda sensor 34 being arranged upstream of the inlet 52 of the secondary air supply in the case of the first exhaust gas system 14.1, the second exhaust gas system is different in that it is disposed downstream of the inlet 52 of the secondary air supply unit. Otherwise both exhaust gas systems 14.1 and 14.2 are identical. In this regard, the description of FIG. 1 also applies to FIG. 2 . Common to both exhaust gas systems is that the secondary air supply takes place downstream of the catalytic converter 30 and upstream of the particulate filter 26 .

In order to more rapidly heat the particulate filter 26 to its operating temperature, an exothermic reaction in the coated particulate filter 26 preferably via a secondary air supply prior to the particulate filter 26 when the combustion chamber mixture is enriched. this is caused In this case, the average exhaust gas lambda 1 before the particulate filter 26 must be observed as precisely as possible in order to avoid unnecessary emissions.

When the temperature of the particulate filter 26 is sufficiently high, combustion of the soot load by excess oxygen and thereby regeneration of the particulate filter 26 is achieved. For this, a defined lean lambda must be maintained before the particulate filter 26 . At the same time, in order to ensure the best possible conversion in the catalytic converter 30, the combustion chamber lambda 1 is set during regeneration.

For heating of the particulate filter 26 , a rich exhaust gas atmosphere, for example, a lambda value of 0.9, must be set downstream of the catalytic converter 30 . At the same time, at the inlet of the particulate filter 26, a stoichiometrically composed (lambda = 1) exhaust gas atmosphere must be created.

For regeneration of the particulate filter 26 , an exhaust gas atmosphere must be created either stoichiometrically (lambda = 1) or slightly rich (eg lambda = 0.99) immediately downstream of the catalytic converter 30 . At the same time, a lean (for example lambda = 1.1) exhaust gas atmosphere should be created at the inlet of the particulate filter 26 .

Whether the secondary air supply is disposed downstream of the second lambda sensor 34 (first exhaust gas system in FIG. 1 ) or upstream of the second lambda sensor 34 (second exhaust gas system in FIG. 2 ) Accordingly, the second lambda sensor 34 performs several tasks.

In the first exhaust gas system, the target lambda is controlled in a closed loop control manner downstream of the catalytic converter 30 by the second lambda sensor. This control sets the combustion chamber lambda correspondingly. The secondary air pump 50 is preferably controlled in an open loop control manner by means of the control device 16 such that the stoichiometric exhaust gas composition (lambda = 1) is set prior to the coated particulate filter 26 . In the second exhaust gas system, the target lambda is controlled by a second lambda sensor 34 in a closed-loop control manner immediately upstream of the coated particulate filter 26 . This control sets the combustion chamber lambda as well as the secondary air supply correspondingly.

For each task of accurately guiding the oxygen concentration, the second lambda sensor 34 has a clear correlation between the prevailing lambda actual value at the mounting position of the second lambda sensor 34 and the signal of this lambda sensor 34 . It can only be done accurately enough when But in most cases this is not the case. Depending on the exhaust gas composition at the mounting position of the second lambda sensor 34, the second lambda sensor may have different output signals even though the actual lambda value is the same.

Illustratively, two effects that can be considered as possible causes for this are described below.

Effect 1: Behind the three-way catalytic converter, a time-varying ratio between hydrogen (H ₂ ) and carbon monoxide (CO) is established when the lambda is constantly enriched. The cause is that water produced from HC and O ₂ in the exhaust gas reacts with CO to produce H ₂ and CO ₂ , and the catalytic converter cannot (continuously) achieve a reaction equilibrium (water gas shift reaction). -gas-shift reaction). After changing from lambda = 1 or lean lambda to constantly rich lambda, the catalytic converter first supplies an amount of H ₂ approximately corresponding to the reaction equilibrium. However, over time the first catalytic converter will supply obviously too much CO relative to H ₂ . Due to the different lateral sensitivities for H ₂ and CO, the lambda sensor after the three-way catalytic converter subsequently outputs a signal that fluctuates greatly with time even though the actual value of the lambda at the mounting position of the second lambda sensor is constant.

Effect 2: When the secondary air supply is activated, for the different lateral sensitivities of the lambda sensor to H ₂ , CO, and O ₂ , the precatalysis of H ₂ and O ₂ within the sensor is effective. Since only a small amount of O ₂ present can be catalytically converted in the sensor, this ratio is highly dependent on the amount of O ₂ present. Also in this case, depending on the exhaust gas composition, a sensor signal different from the sensor signal that may appear without the influence of other exhaust gas components at the same oxygen concentration is set. Due to this lateral sensitivity of the lambda sensor, the output signal not only depends on the oxygen concentration, but also on the concentration of other exhaust gas components.

The present invention provides for correspondingly correcting the output signal of the second lambda sensor 34 mounted between the catalytic converter 30 and the preferably coated particulate filter 26, taking into account the above and similar effects. In particular, the current exhaust gas composition or concentration of the respective relevant exhaust gas components at the location of the second lambda sensor 34 based on the variables available in the control device and the transversal of the second lambda sensor with respect to these exhaust gas components. It is provided to model the sensitivity and to calibrate the output signal of the lambda sensor correspondingly.

In the case of the first exhaust gas system, in which the secondary air supply is implemented downstream of the second lambda sensor 34 , preferably after the catalytic converter 30 H ₂ / varying with time when the lambda is rich or slightly rich It is provided to consider the CO ratio and the different lateral sensitivities of the second lambda sensor to H ₂ and CO as a first effect.

In the case of an exhaust gas system in which the secondary air supply is implemented upstream of the second lambda sensor 34 , preferably, in addition to the first effect, as a second effect, the sensitivity of the lambda sensor to O ₂ and in the second lambda sensor It is provided to consider the precatalysis of H ₂ and O ₂ of

3 shows a flowchart as an embodiment of a method or computer program product 16.2 according to the invention. Block 100 represents the main program for the control of the Otto engine 10 , in which the control device 16 determines in particular the control parameters which cause the Otto engine 10 to generate the required torque.

From this main program 100, a step or a partial program 102 in which the control device 16 reads the signals of the connected sensors is iteratively achieved. In step 102, in particular, the output signal of the second lambda sensor 34 is read. These signals are used as default values for determining different air ratio values.

In step 104 , the control device 16 measures the concentration of one or more further exhaust gas components, according to the output signal of the second lambda sensor 34 , and furthermore the concentration of the further exhaust gas component. Determine the air ratio lambda according to In this case, the concentrations of hydrogen and carbon monoxide are preferably determined as concentrations of another exhaust gas component; When lambda at the outlet of the catalytic converter is rich (i.e. lambda 1 or lambda 3), the time-varying ratio of hydrogen concentration to carbon monoxide concentration and the different lateral sensitivities of the lambda sensor to hydrogen and carbon monoxide are taken into account (the second 1 effect).

Also preferably, the concentrations of hydrogen and carbon monoxide as concentrations of another exhaust gas component are measured; When the lambda at the outlet of the catalytic converter is rich, the time-varying ratio of hydrogen concentration to carbon monoxide concentration and the different lateral sensitivities of the lambda sensor to hydrogen and carbon monoxide are taken into account (first effect); In addition, the sensitivity of the lambda sensor to oxygen and the precatalysis of hydrogen and oxygen, carried out in the lambda sensor, are taken into account (second effect).

This measurement is carried out, for example, according to the method known from DE 10 2012 221 549 A1 or from DE 10 2006 011 894 A1. In the method known from DE 10 2012 221 549 A1, the concentration of another exhaust gas constituent, for example carbon monoxide, carbon dioxide, hydrogen, hydrocarbons or nitrogen oxides, is determined from a computational model by means of the control device or in the control device It is determined based on the available measurement parameters. Then, the output signal of the lambda sensor is converted into a lambda value using the reference characteristic curve of the exhaust gas sensor.

In the case of the method known from DE 10 2006 011 894 A1 for determining the concentration of hydrogen as another exhaust gas component, first of all, when the output signal of a lambda sensor, which is mainly sensitive to oxygen, corresponds to the stoichiometric exhaust gas composition, The output signal is time differentiated. The differentiated output signal is compared with the lower limit. When the time-differentiated output signal exceeds the lower limit, generation of hydrogen in the exhaust gas is detected. Therefore, it is assumed that the influence of the different exhaust gas constituents leads to abrupt changes in the as-yet-differentiated output signal, thus leading to a relatively large value of the time derivative of the output signal. The excess of the lower limit of the differentiated output signal is integrated. Thus, the integral represents the influence of different exhaust gas components on the output signal. In order to correct and compensate for this effect, the correction signal obtained by the integration is subtracted from the output signal.

Thus, the above consideration is carried out by correcting the output signal of the lambda sensor through a correction dependent on the composition of the mixed gas.

The calibrated output signal more accurately indicates the actual oxygen concentration than the uncalibrated output signal of the lambda sensor, since the calibration at least partially excludes the influence of another exhaust gas component that distorts the output signal of the lambda sensor.

The corrected output signal is then further processed as an output signal corrected for the hydrogen lateral sensitivity of the lambda sensor, which further processing is carried out for the purpose of, for example, lambda control.

Lambda control based on the output signal of the lambda sensor becomes highly accurate and reliable as the lateral sensitivities at different engine operating points are taken into account. An excessively high emission of undesirable exhaust gas components can thereby be prevented.

In step 106, it is checked whether regeneration of the coated particulate filter should be started or if regeneration that has already started should proceed. If the test result is NO, the method proceeds to step 114, where it is checked whether the temperature of the preferably coated particulate filter 26 is higher than the minimum temperature required to prepare the particulate filter for operation. If the result of this check is "yes", the heating of the particulate filter, which has been optionally continuously activated, is deactivated in step 115 , and the method proceeds to the main program of block 100 . On the other hand, if the temperature of the particulate filter is too low, branching from step 114 to step 116, in which preferably heating of the coated particulate filter 26 is initiated or continued. Said heating is preferably carried out with the aid of a secondary air supply. The heating is interrupted if, in the iterative method procedure, a negative answer to the query conducted at step 114 is provided, as the case may be.

On the other hand, if the answer is affirmative to the question of the need for regeneration, carried out in step 106 , a temperature check of the particulate filter 26 is carried out in step 108 . If this temperature is high enough to effect regeneration, regeneration is initiated in step 110 or regeneration that has already started continues. Said regeneration is carried out with the aid of a secondary air supply. The method then proceeds to the main program of step 100 .

On the other hand, if the temperature check of the particulate filter performed in step 108 indicates that the temperature is not high enough to initiate or continue regeneration, the program branches to step 112, where the preferably coated coating is performed. Heating of the particulate filter 26 is initiated. After initiation of heating, the method proceeds to the main program of step 100 . The heating is also stopped if, in the iterative method procedure, for example, a negative answer is given to the query made at step 106, or if a temperature related query at step 108 is answered negatively, for example. Heating steps 112 and 116 may differ from each other with respect to the performance of these heating steps, for example with respect to the amount of secondary air supplied respectively.

Replay, once started, is optionally stopped when a negative answer to the query made at step 106 is answered.

Claims (12)

A method for heating and regeneration of a particulate filter (26) disposed downstream of a catalytic converter (30) in an exhaust gas stream of an Otto engine (10), said auto engine (10) comprising a catalytic converter (30) and a particulate filter (26) a method of heating and regenerating a particulate filter comprising a device (50) for supplying secondary air to the exhaust gas stream between
The auto engine 10 and the device 50 for supplying secondary air,
- between the catalytic converter 30 and the particulate filter 26 a predetermined value of the air ratio lambda is achieved,
- the output signal of a lambda sensor 34 arranged in the exhaust gas stream between the catalytic converter 30 and the particulate filter 26 to detect oxygen as an exhaust gas component is detected,
- the concentration of one or more other exhaust gas constituents is controlled to be calculated;
The value of the air ratio lambda is determined according to the detected output signal and further according to the concentration of one or more other exhaust gas components, taken into account in the control of at least one of the Otto engine 10 and the device 50 , ,
The auto engine 10 and the device 50 for secondary air supply, for heating the particulate filter 26 , have an air ratio representing the first excess fuel in the exhaust gas atmosphere therein as time averaged at the outlet of the catalytic converter 30 . a first value of lambda is adjusted and is driven to adjust a second value of the air ratio lambda corresponding to the stoichiometric composition of the exhaust gas atmosphere therein as time averaged at the inlet of the particulate filter 26;
The automatic engine 10 and the device 50 for the secondary air supply are also for regeneration of the particulate filter 26, at the outlet of the catalytic converter 30 at least in the exhaust gas atmosphere therein, as time averaged, at least a first A third value of the air ratio lambda representing a second excess fuel or stoichiometric value less than the excess fuel is adjusted, and at the inlet of the particulate filter 26 a fourth value of the air ratio lambda corresponding to excess air in the exhaust atmosphere therein is A method of heating and regenerating a particulate filter, characterized in that it is driven to be adjusted. delete Method according to claim 1 , characterized in that the concentration of one or more other exhaust gas constituents is modeled from measurement parameters provided in the control device ( 16 ) of the Otto engine ( 10 ). 2 . The first exhaust gas system ( 14.1 ) according to claim 1 , wherein the first value and the third value are the supply of secondary air to the exhaust gas stream between the lambda sensor ( 34 ) and the particulate filter ( 26 ). ) in the heating and regeneration method of the particulate filter, characterized in that it is adjusted through the fluctuation of the combustion chamber lambda of the Otto engine (10). 5. A method according to claim 4, characterized in that the second value and the fourth value are adjusted through a change in the supply of secondary air into the exhaust gas stream. 4. The method according to claim 1 or 3, wherein the concentrations of hydrogen and carbon monoxide are measured as concentrations of another exhaust gas component; The time-varying ratio of hydrogen concentration to carbon monoxide concentration and the different lateral sensitivities of the lambda sensor 34 for hydrogen and carbon monoxide are taken into account when lambda at the outlet of the catalytic converter is rich; A method for heating and regenerating a particulate filter, characterized in that. 2. A second exhaust gas system (14.2) according to claim 1, wherein the first value and the third value are the secondary air supply to the exhaust gas flow between the catalytic converter (30) and the lambda sensor (34). ) through a mutually matched adjustment of the combustion chamber lambda and secondary air supply in the heating and regeneration method of the particulate filter. 8. A method according to claim 7, characterized in that the second value and the fourth value are adjusted through a change in the supply of secondary air to the exhaust gas stream. 8. The method of claim 7, wherein the concentrations of hydrogen and carbon monoxide as concentrations of another exhaust gas component are measured; The time-varying ratio of hydrogen concentration to carbon monoxide concentration and the different lateral sensitivities of the lambda sensor 34 for hydrogen and carbon monoxide are taken into account when lambda at the outlet of the catalytic converter 30 is rich; In addition, the lateral sensitivity of the lambda sensor to oxygen and the precatalysis of hydrogen and oxygen, carried out in the lambda sensor, are taken into account; A method for heating and regenerating a particulate filter, characterized in that. a catalytic converter 30 disposed in the exhaust gas stream of the Otto engine 10; a particulate filter 26 disposed downstream of the catalytic converter 30; a device (50) for supplying secondary air to the exhaust gas stream between the catalytic converter (30) and the particulate filter (26); In the auto engine (10) having; a lambda sensor (34) disposed between the catalytic converter (30) and the particulate filter (26) to sense oxygen,
Otto engine (10), characterized in that the control device (16) is designed to carry out the steps of the method of claim 1 or claim 3 . A computer program, stored on a computer readable medium, comprising instructions for executing the steps of the method of claim 1 or claim 3 . A computer readable medium having the computer program product of claim 11 stored thereon in a computer readable form.

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