KR102517209B1 - Method and control unit for operating a particle filter - Google Patents

Abstract

The present invention relates to a method for operating a particulate filter (25) in an exhaust aftertreatment system of an internal combustion engine, in particular for performing regeneration of the particle filter and/or for heating the particulate filter, said exhaust aftertreatment system includes at least a first lambda sensor, a first catalytic converter, a secondary air inlet, and a particle filter along an exhaust gas channel in a flow direction of the exhaust gas. In the method, the lambda of the exhaust gas upstream of the first catalytic converter is adjusted using the signal of the first lambda sensor; by adjusting the lambda of the exhaust gas upstream of the particle filter by means of a controlled secondary air supply into the exhaust gas channel between the first catalytic converter and the particle filter; A lambda adjustment of the exhaust gas upstream of the particle filter in the flow direction, suitable for the operation of the particle filter, is carried out.
The invention also relates to a control unit for carrying out the method.
The method and control unit allow for optimized operation of the particle filter.

Description

Method and control unit for operating a particle filter {METHOD AND CONTROL UNIT FOR OPERATING A PARTICLE FILTER}

The present invention relates to a method for operating a particle filter in an exhaust aftertreatment system of an internal combustion engine, in particular for performing regeneration of the particle filter and/or for heating the particle filter, said exhaust aftertreatment system comprising the exhaust gas and at least a lambda sensor, a first catalytic converter, a secondary air inlet, and a particle filter along the exhaust gas channel in the flow direction of .

The invention also relates to a control unit for the operation of a particle sensor in an exhaust gas channel of an internal combustion engine, to which an exhaust gas aftertreatment system is assigned, which exhaust gas aftertreatment system operates in the direction of exhaust gas flow. at least a first lambda sensor, a first catalytic converter, a secondary air inlet, and a particle filter along an exhaust gas channel, wherein the control unit is supplied with at least one output signal of the first lambda sensor, and the control unit is It is connected to the engine's fuel metering system.

In today's engine control systems, lambda sensors are used for detecting the oxygen concentration in the exhaust gas and for lambda adjustment of the engine. In this case, a broadband lambda sensor and a discrete level lambda sensor are used.

Broadband lambda sensors are typically used where rich or lean lambda values must be accurately measured, or where measurements in the range around lambda = 1 are sufficient with limited accuracy. Discrete level lambda sensors are used where exhaust gas lambda within a range around lambda = 1 must be measured with high accuracy.

A typical application of a broadband lambda sensor is in lambda regulation upstream of a catalytic converter and balancing oxygen inflow and outflow during diagnosis of a catalytic converter. Typical applications of discrete level lambda sensors are in the highly accurate regulation of lambda = 1 downstream of a catalytic converter and in the detection of breakthrough of rich or lean exhaust gases in the diagnosis of catalytic converters.

In particular, in order to comply with legal emission and diagnostic requirements (e.g. SULEV), typical exhaust gas systems of recent internal combustion engines, in particular gasoline engines, have a first lambda sensor, in particular a broadband lambda sensor, downstream of the internal combustion engine in the flow direction of the exhaust gases; a first three-way catalytic converter, a second lambda sensor, in particular a discrete level lambda sensor and a second unmonitored three-way catalytic converter.

More stringent emissions and diagnostics requirements of the future (eg China 6) require exhaust aftertreatment systems where the second catalytic converter must also be monitored. At the same time, the number of particles in the exhaust gas must be limited. To achieve this, it may be required to combine the second three-way catalytic converter with a particle filter, or to use a catalyst-coated particle filter (four-way catalytic converter) instead of the second catalytic converter.

Also, a secondary air inlet may be provided between the first catalytic converter and the second catalytic converter. The secondary air inlet may join the exhaust gas channel upstream or downstream of the second lambda sensor in the flow direction of the exhaust gas. With the help of the secondary air inlet, fresh air (secondary air) can be introduced into the exhaust gas channel upstream of the second catalytic converter and thus upstream of the particle filter.

With the help of a particle filter, soot particles arising from the exhaust gas during combustion of an internal combustion engine are filtered out. When the storage capacity of the particle filter is reached, regeneration of the particle filter must be performed. To this end, the temperature of the particulate filter rises until the accumulated soot is burned in an exothermic proceeding reaction. To raise the temperature, measures internal to the engine or injection of fuel into the exhaust gas channel can be performed. Sufficient oxygen must be present in the exhaust gas to enable combustion of the soot. Accordingly, there must be a lean exhaust gas (lambda greater than 1) upstream of the particulate filter. In view of this, document D1 (DE 10 2011 100 677 A1) describes a method for operating a diesel engine with an emission control system consisting of an oxidation catalytic converter, preferably a three-way catalytic coating, a particle filter and an SCR catalytic converter. . For regeneration of the particulate filter, the diesel engine is operated with a lambda of at least near unity to achieve a good conversion of the harmful substances in the oxidation catalytic converter. Between the oxidation catalytic converter and the particle filter, air is conducted into the exhaust gas channel so that simultaneous combustion of the soot particles of the particle filter is possible. The secondary air supply is particularly controlled so that a pre-set soot burning rate is obtained. For this purpose, the exhaust gas temperature difference with respect to the particle filter is used as a control variable.

In order to realize the catalytic action of the three-way catalytic converter or catalyst-coated particle filter combined with the particle filter, the particle filter must have a sufficient operating temperature. The internal combustion engine is operated with a rich mixture and the catalytic converter/particle filter so that the temperature of the combined particulate filter rises rapidly to the required operating temperature, for example after a cold start of the internal combustion engine or after a long period of operation in coasting mode. It is known to introduce secondary air upstream into the exhaust gas duct of an internal combustion engine. The hydrocarbons in the exhaust gas are then burned upstream or within the catalytic converter by means of the oxygen of the secondary air to heat the catalytic converter. In this case, upstream of the particulate filter, preferably one or more lambdas are adjusted.

To accurately adjust the lambda of the exhaust gas upstream of the particle filter (as a combination of a three-way catalytic converter and a particle filter or as a catalyst-coated particle filter) for regeneration or rapid heating of the particle filter, The amount of primary air may be regulated by a second lambda sensor disposed between the first catalytic converter and the particle filter. For this purpose, the introduction of secondary air has to be carried out upstream of the second lambda sensor in the flow direction.

A prerequisite for precise control of the supplied secondary air is that a clear relationship is formed between the signal of the lambda sensor and the actual lambda of the exhaust gas at the mounting position of the second lambda sensor, because otherwise, the above This is because the accuracy of signal-based control is insufficient, and excessively high emissions or damage to the particle filter may occur. Since the signal from the lambda sensor is usually influenced by the different cross-sensitivities of the lambda sensor to different exhaust gas components, eg CO, CO ₂ , H ₂ , H ₂ O, HC, NO _x , O ₂ , And since the exhaust gas composition can be different under different operating conditions of the internal combustion engine even with the same exhaust gas lambda, the above prerequisite is usually not fulfilled not only with a broadband lambda sensor but also with a discrete level lambda sensor.

Thus, for example, downstream of the three-way catalytic converter, the time-varying ratio between hydrogen (H ₂ ) and carbon monoxide (CO) is adjusted under constant rich lambda conditions. The cause lies in the so-called water-gas shift reaction, which the catalytic converter cannot continuously balance. After lambda = 1 or change from lean lambda to constant rich lambda, the catalytic converter initially supplies an amount of H ₂ corresponding to approximately equilibrium. However, over time the catalytic converter apparently supplies too much CO relative to H ₂ . Even if the lambda at the sensor location is constant, due to the different cross-sensitivities to H ₂ and CO, the lambda sensor indicates a transiently strongly fluctuating signal downstream of the three-way catalytic converter.

According to another undesirable effect, the pre-catalysis of H 2 by _{O 2} in the lambda sensor for the different cross-sensitivities of the lambda sensor to H ₂ , CO and O ₂ during activated secondary _air injection It affects. Since only a small amount of O ₂ present can be converted catalytically in the lambda sensor, this fraction is highly dependent on the amount of O ₂ present. Here too, even if the lambda at the sensor position is constant, the other sensor signals of the lambda sensor are adjusted according to the exhaust gas composition.

Accordingly, there is a disadvantage in that complex modeling of the exhaust gas composition downstream of the first catalytic converter and the cross-sensitivity of the second lambda sensor is required in order to achieve the necessary accuracy when metering the secondary air.

SUMMARY OF THE INVENTION The object of the present invention is to provide a method enabling optimized operation of a particle filter arranged downstream of a first catalytic converter and subsequent secondary air inlet.

Another object of the present invention is to provide a control unit suitable for carrying out the method.

The object of the invention related to the device is that the lambda of the exhaust gas upstream of the first catalytic converter is adjusted using the signal of the first lambda sensor; As the lambda of the exhaust gas upstream of the particle filter is regulated by means of a controlled secondary air supply into the exhaust gas channel between the first catalytic converter and the particle filter; This is achieved by performing a lambda adjustment of the exhaust gas upstream of the particle filter in the flow direction, suitable for the operation of the particle filter. The first lambda sensor is used for balancing the inflow and outflow of oxygen, in normal operation of the internal combustion engine, in lambda regulation upstream of the catalytic converter and, optionally, in diagnostics of the catalytic converter. Optionally, the cross sensitivity of the first lambda sensor is corrected through relatively simple modeling for normal operation of the exhaust aftertreatment system as is known in the prior art. Thus, the lambda of the exhaust gas upstream of the first catalytic converter can be accurately measured and adjusted by means of the first lambda sensor. As the storage capacity of the first catalytic converter is exceeded, the lambda regulated upstream of the first catalytic converter also exists downstream of the first catalytic converter. Knowing the lambda downstream of the first catalytic converter, it is possible to determine the required amount of secondary air to be supplied to the exhaust gas upstream of the particle filter in order to adjust the lambda suitable for the operation of the particle filter. Due to this, the exhaust gas lambda upstream of the particulate filter can be precisely adjusted through the controlled supply of secondary air according to the invention. The amount of secondary air supplied is determined by the lambda regulated upstream of the first catalytic converter. It is unnecessary to use the signal of the second lambda sensor arranged between the first catalytic converter and the particle filter. Thus, complicated correction of the cross sensitivity of the second lambda sensor can be omitted.

For the purpose of providing optimal operating conditions for regeneration of the particle filter, upstream of the first catalytic converter, a lambda of less than or equal to 1, in particular a lambda between 0.95 and 1.00, is adjusted upstream of the first catalytic converter to effect the regeneration of the secondary air. Through controlled feeding it is possible to adjust lean lambda upstream of the particulate filter, in particular lambda in the range of 1.05 to 1.2. Thereby, sufficient oxygen is present in the exhaust gas to raise the temperature of the particle filter such that combustion of soot particles as well as unburned hydrocarbons occurs. In this case, the rate of combustion of the soot particles can be influenced through an appropriate variation of the lambda of the exhaust gas upstream of the first catalytic converter and/or the volumetric flow rate of the supplied secondary air.

Rapid heating of the particulate filter to the desired operating temperature is achieved through controlled supply of secondary air, wherein a rich lambda, in particular lambda in the range of 0.85 to 0.95, is adjusted upstream of the first catalytic converter to effect heating of the particulate filter. This can be achieved by adjusting one or more lambdas upstream of the particle filter.

The adjustment accuracy of each required lambda upstream of the particulate filter can be improved by taking into account the current exhaust gas mass flow in the controlled supply of secondary air. If the lambda upstream of the first catalytic converter as well as the lambda downstream of the first catalytic converter are known, and if the exhaust gas mass flow is known, then each required particle filter must be added to the exhaust gas in order to precisely adjust the lambda upstream. Secondary air demand can be accurately determined and adjusted.

Monitoring of the correct performance of the heating or regeneration of the particle filter is carried out through the output signal of the second lambda sensor arranged downstream of the secondary air inlet and upstream of the particle filter in the direction of flow of the exhaust gas, through the regeneration and/or Alternatively, it may be performed by monitoring whether lean lambda or lambda = 1 condition is created to perform heating. The detection of such a lean lambda can be performed with sufficient accuracy without correction of the cross sensitivity of the second lambda sensor.

According to one preferred embodiment of the present invention, the function of the secondary air inlet can be monitored via the output signal of the second lambda sensor. For example, a failure of the secondary air pump supplying secondary air to the secondary air inlet can be recognized simply and quickly in this way. This makes it possible to reliably detect if there is a defect in the secondary air inlet and thus the required lambda for optimal operation of the particle filter cannot be adjusted.

For optimal operation of the particle filter, especially for the purpose of performing rapid heating or regeneration of the particle filter, it is desirable to adjust lambda both upstream of the first catalytic converter and downstream of the first catalytic converter to be non-unity. Thus, according to an advantageous variant of the invention, it is possible for the lambda upstream of the first catalytic converter to be regulated using a broadband lambda sensor. With this broadband lambda sensor, the oxygen concentration of the exhaust gas is detected within a wide range around lambda = 1, and lambda can be adjusted accordingly.

Preferably, the lambda of the exhaust gas upstream of the particulate filter can be adjusted by means of a controlled supply of secondary air as the storage capacity of the first catalytic converter is exceeded and a breakthrough of the rich exhaust gas appears. From the rich exhaust gas, the lambda upstream of the particulate filter can be adjusted to lambda 1 or lean by means of a corresponding supply of secondary air. In this case, lambda of the exhaust gas downstream of the first catalytic converter and after breakthrough of the rich exhaust gas corresponds to lambda upstream of the first catalytic converter. Since this lambda is accurately known through measurement by means of a first lambda sensor arranged upstream of the first catalytic converter, the secondary air demand to be supplied to the exhaust gas can be precisely determined in order to adjust the desired lambda upstream of the particle filter.

The method can preferably be used for a combined particle filter with a three-way catalytic converter or a catalyst-coated particle filter (four-way catalytic converter).

The problem of the present invention related to the control unit is that the control unit adjusts the lambda of the exhaust gas upstream of the first catalytic converter through control of the fuel metering system according to the output signal of the first lambda sensor, thereby inducing, It is designed to adjust the control of the air/fuel mixture supplied to the internal combustion engine to a pre-adjusted value, the control unit controls the secondary air pump and, through it, directs the flow into the exhaust gas channel upstream of the particulate filter. This is achieved by controlling the controlled secondary air supply, which is designed to adjust the lambda of the exhaust gas upstream of the particle filter to a value suitable for regeneration or heating of the particle filter. As such, the control unit makes it possible to perform the method described above.

In the following, the present invention will be described in more detail based on the embodiments shown in the drawings.

1 is a schematic diagram of an exhaust gas aftertreatment system of an internal combustion engine with a secondary air inlet arranged downstream of a second lambda sensor;
2 is a schematic diagram of an exhaust gas aftertreatment system of an internal combustion engine with a secondary air inlet arranged upstream of a second lambda sensor.

1 is a schematic diagram of an exhaust gas aftertreatment system 20 of an internal combustion engine 10 with a secondary air inlet 27 arranged downstream of a second lambda sensor 24 .

Exhaust gas 11 of internal combustion engine 10 is guided through exhaust gas aftertreatment system 20 along exhaust gas channel 21 . At this time, the first catalytic converter 23 is disposed in the flow direction of the exhaust gas 11 along the exhaust gas channel 21, followed by a particle filter 25 disposed in the exhaust gas channel 21. A first lambda sensor 22 is provided between the internal combustion engine 10 and the first catalytic converter 23 . The second lambda sensor 24 is arranged immediately after the first catalytic converter 23 in the exhaust gas channel 21 . A third lambda sensor 26 is disposed downstream of the particle filter 25 in the exhaust gas channel 21 . The secondary air inlet 27 is connected to the exhaust gas channel 21 between the first catalytic converter 23 and the particle filter 25 . At this time, the secondary air inlet is disposed downstream of the second lambda sensor 24 in the flow direction. Secondary air 12 may be supplied to the exhaust gas channel 21 through the secondary air inlet 27 .

2 is a schematic diagram of an exhaust gas aftertreatment system 20 of an internal combustion engine 10 with a secondary air inlet 27 arranged upstream of the second lambda sensor 24 . Except for the fact that the arrangement of the secondary air inlet 27 and the second lambda sensor 24 are reversed, the structure of the exhaust gas aftertreatment system 20 shown in FIG. 1 is the same. Accordingly, like components are indicated likewise.

The internal combustion engine 10 shown in Figs. 1 and 2 is mainly implemented as a gasoline engine. The first lambda sensor 22 is a broadband lambda sensor. This lambda sensor is used to adjust the air/fuel mixture ratio supplied to the internal combustion engine (10). To this end, a signal from the first lambda sensor 22 is supplied to an engine control unit (not shown). A correction of the lambda value measured by the first lambda sensor 22 is performed in the engine control unit. As a result, errors caused by the cross sensitivity of the first lambda sensor to different exhaust gas constituents are corrected. Such cross-sensitivities are formed for example for carbon monoxide, carbon dioxide, hydrogen, water, hydrocarbons, nitrogen oxides and oxygen. Through a corresponding correction of this cross sensitivity, the lambda of the exhaust gas 11 upstream of the first catalytic converter 23 can be accurately detected.

The first catalytic converter 23 is implemented as a three-way catalytic converter. These three-way catalytic converters have limited storage capacity for oxygen and unburned hydrocarbons. If the limit of the storage capacity of the three-way catalytic converter is reached after a corresponding supply of lean exhaust gas or rich exhaust gas, a lean breakthrough (lean breakthrough) in which the lean exhaust gas or rich exhaust gas is passed through the three-way catalytic converter in an unconverted state ) or rich breakthrough occurs. This lean or rich breakthrough can be detected by the second lambda sensor 24 . For this purpose, the cross sensitivity of the second lambda sensor 24 does not need to be calibrated.

The particle filter 25 is here embodied as a catalyst coated particle filter 25 . Such a catalyst-coated particle filter 25 is also referred to as a four-quadrant catalytic converter. It is also conceivable to combine the particle filter 25 with a three-way catalytic converter as a constituent unit.

During operation of the internal combustion engine 10 , the detected soot particles are filtered from the exhaust gas 11 by a particle filter 25 . When the storage capacity of the particle filter 25 is full, the particle filter must be regenerated. In this case, the accumulated soot particles are burned.

In order to maintain the conversion capability of the catalytic coating of the particle filter 25, the particle filter 25 must have a required operating temperature. In this case, the operating temperature must be reached as quickly as possible after a cold start of the internal combustion engine 10, for example, in order to avoid an increase in the emission of harmful substances.

Using the third lambda sensor 26 , a lean or rich breakthrough of the coated particle filter 25 can be detected.

In order to allow the particulate filter 25 to heat up more quickly to its operating temperature, the coated particulate filter 25 is supplied with secondary air 12 into the exhaust gas channel 21 upstream of the particulate filter 25 at a rich combustion chamber mixture ratio. ) causes an exothermic reaction in In order to avoid unnecessary emissions, an average exhaust gas lambda of at least one upstream of the particulate filter 25 should be observed as precisely as possible.

If the temperature of the particle filter 25 is sufficiently high, combustion of the captured soot amount in case of excess oxygen and thus regeneration of the particle filter 25 can be achieved. For this, the lean lambda as defined upstream of the particle filter 25 must be maintained. At the same time, lambda 1 is adjusted in the combustion chamber of the internal combustion engine 10 during regeneration in order to ensure as good a conversion as possible of the first catalytic converter 23 .

This suggests the following lambda target values for optimal operation of the particle filter 25:

입자 필터의 가열:

Heating of the particle filter:

- lambda downstream of the first catalytic converter (23): rich (e.g. lambda = 0.9)

- Lambda upstream of the particle filter 25: 1 (or at least greater than 1)

입자 필터의 재생:

Regeneration of particle filters:

- lambda downstream of the first catalytic converter 23" 1 or slightly enriched (e.g. lambda = 0.99)

- lambda upstream of the particle filter (25): sparse (e.g. lambda = 1.1)

Controlling the lambda upstream of the particulate filter 25 in the flow direction of the exhaust gas 11 using the second lambda sensor 24 controls the exhaust gas composition at the position of the second lambda sensor 24 and the different exhaust This is not possible without taking into account the cross-sensitivity of the second lambda sensor to the gas composition, since the sensor can indicate different signals even with the same exhaust gas lambda when the exhaust gas composition is different.

Therefore, according to the invention, the lambda upstream of the first catalytic converter 23 is adjusted by the first lambda sensor 22 to a corresponding target value, so that the required lambda downstream of the first catalytic converter 23 can be adjusted. .

The lambda regulated upstream of the first catalytic converter 23 is also regulated downstream of the first catalytic converter 23 as soon as its storage capacity is exceeded. In this case, the lambda can be precisely adjusted upstream of the first catalytic converter 23 and thus also downstream of the first catalytic converter 23 on the basis of the output signal of the first lambda sensor 22, since the first lambda This is because the cross sensitivity of the sensor 22 is corrected. Continuing according to the invention, the combination of the metered secondary air 12 with the exhaust gas lambda upstream of the secondary air inlet 27 adjusts the desired lambda upstream of the particle filter 25, the secondary air A configuration for pilot controlling the supply of the secondary air 12 through the inlet 27 is provided. Preferably, in addition to the exhaust gas lambda, the current exhaust gas mass flow is also taken into account when determining the amount of secondary air to be metered in.

When the secondary air inlet 27 is arranged upstream of the second lambda sensor 24, as shown in FIG. 2, the signal of the second lambda sensor 24 actually upstream of the particle filter 25 It can be used to detect if lean lambdas needed for regeneration or heating are present. This detection is not adversely affected by the aforementioned cross-sensitivity of the second lambda sensor 24 . Similarly, the functionality of the secondary air inlet 27 can be monitored using the second lambda sensor 24 .

Claims (10)

A method for operating a particle filter (25) in an exhaust gas aftertreatment system (20) of an internal combustion engine (10), wherein the exhaust gas aftertreatment system (20) is an exhaust gas channel ( A method of operating a particle filter comprising at least a lambda sensor (22), a first catalytic converter (23), a secondary air inlet (27) and a particle filter (25) along 21),
lambda of the exhaust gas 11 upstream of the first catalytic converter 23 is adjusted using the signal of the first lambda sensor 22; Regulation of the lambda of the exhaust gas 11 upstream of the particulate filter 25 by means of a controlled supply of secondary air 12 into the exhaust gas channel 21 between the first catalytic converter 23 and the particulate filter 25 by becoming; lambda adjustment of the exhaust gas (11) upstream of the particle filter (25) in the flow direction, suitable for the operation of the particle filter (25), is carried out;
After the storage capacity of the first catalytic converter 23 has been exceeded and breakthrough of the rich exhaust gas has occurred, the control of the exhaust gas 11 upstream of the particulate filter 25 by the controlled supply of secondary air 12 has occurred. A method of operating a particle filter, characterized in that lambda is adjusted. 2. The method according to claim 1, wherein upstream of the first catalytic converter (23) a lambda of less than or equal to 1 is regulated to carry out regeneration of the particle filter (25), via a controlled supply of secondary air (12) to the particle filter ( 25) A method of operating a particle filter, characterized in that upstream the lean lambda is adjusted. 3. The method according to claim 1 or 2, in which the rich lambda is regulated upstream of the first catalytic converter (23) to effect heating of the particulate filter (25), and the particulate is supplied via a controlled supply of secondary air (12). A method of operating a particle filter, characterized in that upstream of the filter (25) at least one lambda is adjusted. 3. Method according to claim 1 or 2, characterized in that the current exhaust gas mass flow is taken into account during the controlled supply of secondary air (12). According to claim 1 or 2, the output signal of the second lambda sensor (24) disposed downstream of the secondary air inlet (27) and upstream of the particle filter (25) in the flow direction of the exhaust gas (11) characterized in that it is monitored whether a lean lambda or a condition where lambda = 1 is created to carry out regeneration and/or heating of the particle filter (25) via the filter. 6. Method according to claim 5, characterized in that the function of the secondary air inlet (27) is monitored via the output signal of the second lambda sensor (24). 3. Method according to claim 1 or 2, characterized in that the lambda upstream of the first catalytic converter (23) is regulated using a broadband lambda sensor. delete 3. The method according to claim 1 or 2, used for a combined particle filter (25) with a three-way catalytic converter or a catalyst-coated particle filter (25) (four-way catalytic converter). As a control unit for the operation of the particulate filter 25 in the exhaust gas channel 21 of the internal combustion engine 10, an exhaust gas aftertreatment system 20 is assigned to the internal combustion engine 10, which exhaust gas aftertreatment system 20 is at least a first lambda sensor 22, a first catalytic converter 23, a secondary air inlet 27, and a particle filter along the exhaust gas channel 21 in the flow direction of the exhaust gas 11 ( 25), wherein the control unit is supplied with at least one output signal of the first lambda sensor (22) and the control unit is connected to the fuel metering system of the internal combustion engine (10).
The control unit adjusts the lambda of the exhaust gas 11 upstream of the first catalytic converter 23 through the control of the fuel metering system according to the output signal of the first lambda sensor 22, thereby inducing , designed to adjust the control to a pre-adjusted value of the air/fuel mixture supplied to the internal combustion engine 10;
The control unit controls the secondary air pump and, through the controlled supply of secondary air 12 into the exhaust gas channel 21 upstream of the particle filter 25, which is guided by it, controls the particle filter 25. It is designed to adjust the lambda of the upstream exhaust gas (11) to a value suitable for regeneration or heating of the particle filter (25),
The control unit controls the exhaust upstream of the particulate filter 25 by means of a controlled supply of secondary air 12 after the storage capacity of the first catalytic converter 23 has been exceeded and breakthrough of the rich exhaust gas has occurred. Control unit, designed to adjust the lambda of the gas (11).

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