DE102008032601A1 - Exhaust gas flow condition adjusting method for e.g. diesel engine, of motor vehicle, involves supplying secondary air mass flow to burner, where burner lambda value produced from injection amount and mass flow amounts to less than one - Google Patents

Abstract

The method involves supplying injection amount of fuel into a burner (57) in a controllable or regulatable manner. Secondary air mass flow is supplied into the burner in a controllable or regulatable manner, where a burner lambda value produced from the injection amount and the secondary air mass flow amounts to less than 1. The burner is associated with an exhaust gas flow (3) of an internal combustion engine (5) of a motor vehicle (7), where the motor vehicle has an exhaust gas system (11) passing through the exhaust gas flow and downstream the internal combustion engine. An independent claim is also included for an arrangement for adjusting a condition of an exhaust gas flow of an internal combustion engine of a motor vehicle.

Description

The The invention relates to a method for setting a state an exhaust gas stream of an internal combustion engine of a motor vehicle with one of the internal combustion engine downstream of the exhaust stream perfused exhaust gas treatment device by means of a the exhaust flow associated burner and an arrangement for adjusting a state of exhaust gas flow.

Methods and arrangements for adjusting a state of an exhaust gas flow are known. By increasing a temperature of the exhaust gas stream, for example, a regeneration of a particulate filter and / or a desulfurization of catalysts can be carried out. For this purpose, the temperature of the exhaust gas stream can be raised via an exhaust gas temperature resulting during normal operation of the internal combustion engine. An increase in temperature can also take place during a cold start of the internal combustion engine. Furthermore, it is known to increase the exhaust gas temperature by means of internal engine intervention. The DE 10 2004 022 186 describes a method for supplying clean compressed air to a diesel oxidation catalyst. Here, compressed air is introduced before a diesel oxidation catalyst. A tap of the introduced before the oxidation catalyst fresh air takes place in front of a turbocharger of the engine. The DE 44 43 133 A1 describes the thermal regeneration of a particulate filter by means of a burner, wherein the burner is supplied by an exhaust gas turbocharger of the internal combustion engine with combustion air.

From the DE 38 37 472 A1 is known a particulate filter system, wherein a regeneration of a particulate filter by burning the particle coating in the full flow of the exhaust gas takes place. Fuel and oxygen containing gas is supplied to a burner associated with the particulate filter, wherein the ratio of the fuel supplied to the burner to the oxygen-containing gas at the operating point of the diesel engine at which the power requirement of the burner to reach the regeneration temperature is lowest is approximately stoichiometric and all others Operating points of the diesel engine is substoichiometric. The burner consists of a Luftdrallzerstäuberdüse, a primary combustion chamber and a secondary combustion chamber. The primary combustion chamber has an axial outlet opening. The secondary combustion chamber is cylindrical, like the primary combustion chamber. The primary combustion chamber adjoins the particle filter, wherein a circular baffle plate is provided between the outlet opening of the primary combustion chamber and the particle filter. The opening of the primary combustion chamber before mounted baffle plate is intended to prevent unburned when the primary combs unburned fuel reaches the particulate filter and this endangered by overheating.

From the DE 10 2006 009 943 A1 is an exhaust aftertreatment system with in the direction of flow of exhaust gas of an internal combustion engine arranged in succession, exhaust gas flowed first oxidation catalytic converter, a NOx catalyst device for denitrification of the exhaust gas, means for actively raising an exhaust gas temperature with at least a second oxidation catalyst device, and a device known for particle removal. In this case, a respective operating temperature of the NOx catalyst device and the device for particle removal is adjustable as a function of an exhaust gas temperature and an output of the internal combustion engine. In order to generate a heat tone for the temperature control, a corresponding unit is provided upstream of one or more of the catalyst devices.

task The invention is an improved method for adjusting a state of an exhaust gas flow of an internal combustion engine of a Motor vehicle to provide, in particular an improved control to enable.

The The object is achieved with the features of the independent claims solved.

The Task is with a method for setting a state of a Exhaust gas flow of an internal combustion engine of a motor vehicle with one of Internal combustion engine downstream and flowed through by the exhaust stream Dissolved exhaust system by means of a burner associated with the exhaust stream. The method provides controlled or regulated feeding an injection amount of a fuel into the burner and a supply a secondary air mass flow into the burner before, wherein a from the injection quantity and the secondary air mass flow resulting burner λ value is less than 1. Advantageously, the fuel in the burner only partially implemented be, with a burner exhaust stream relatively reactive partially reacted hydrocarbons and / or carbon monoxide, the in the exhaust gas flow by means of the residual oxygen present there despite possibly unfavorable conditions like one high space velocity and / or a low exhaust gas temperature can be implemented. The assignment of the burner to the exhaust system can in particular by means of firing the burner exhaust gas stream in the means the exhaust system guided exhaust gas flow.

The internal combustion engine may be a lean-ignition lean-burn engine and / or a diesel engine, the exhaust gas flow containing a lean exhaust gas. Advantageously, a thermo management for the exhaust system. State can be understood as any parameter characterizing the exhaust gas flow, for example a temperature, a composition and / or an exhaust gas λ value.

at an embodiment of the method is provided that the burner λ value is more than 0.25 and less than 0.9, in particular is more than 0.35 and less than 0.75. Advantageous can also adjust the λ value by adjusting the burner λ value of the acted upon by a burner exhaust gas of the burner exhaust gas stream be set.

at Another embodiment of the method is an adjustment of the burner λ value at constant supplied Injection quantity by controlling the secondary air mass flow, and / or adjusting the torch λ value at constant supplied secondary air mass flow by means of taxes the injection quantity and / or adjusting the burner λ value by controlling the injection quantity and the secondary air mass flow intended. Advantageously, for example, with a constant injection quantity a constant heat output can be assumed as the fuel at the latest in the exhaust gas flow completely thermally is implemented. An influence of a temperature of the secondary air mass flow on the resulting final temperature of the exhaust stream can be considered become. Alternatively, it is advantageously possible, the burner λ value by controlling the injection amount, thereby also a desired heating power is adjustable. A combination by controlling the injection quantity and the secondary air mass flow enables a particularly flexible adjustment of the state the exhaust stream.

The The object is also a method of adjustment a state of an exhaust gas flow of an internal combustion engine of a Motor vehicle with one of the internal combustion engine downstream and exhaust gas flowing through the exhaust gas flow solved by means of a burner associated with the exhaust stream. The method provides for controlling a temperature of the exhaust stream after the exhaust treatment device by controlling a burner deliverable injection amount of fuel and a control a secondary air mass flow that can be fed to the burner by controlling a flow through the secondary air mass flow Flow limiting device before. It is advantageously possible, for example, by controlling the injection amount a desired heating power to provide for reaching the temperature of the exhaust stream. simultaneously Is it possible to complete the thermal Implementation of the fuel necessary secondary air mass flow to adjust by means of the flow limitation device. Advantageous It is also possible, other parameters, for example to set the burner λ value.

at an embodiment of the method is a generating the Secondary air mass flow by means of a compressed air source and / or generating the secondary air mass flow means one of the flow limiting device upstream compressed air source and / or generating the secondary air mass flow and supplying the internal combustion engine with combustion air by means of the compressed air source, this at least one element of the following Group comprising: a compressor, an exhaust gas turbocharger, a Compressor, a Komprex charger, a compressed air reservoir provided. Advantageous can the compressed air source equally for the Supplying the internal combustion engine and the burner with combustion air be used. An otherwise usually necessary additional burner fan can be omitted. By means of the flow-limiting device can the secondary air mass flow can be controlled.

at Another embodiment of the method is measuring a temperature indicative of the actual temperature after the exhaust treatment device by means of a the exhaust gas flow associated and the exhaust treatment device downstream first temperature measuring device and / or predetermining a desired temperature and / or Controlling the injection quantity as a function of predetermined target temperature and the measured actual temperature is provided. Advantageously, a closed loop for the temperature the exhaust stream can be realized.

at Another embodiment of the method is measuring a further actual temperature of the exhaust stream upstream of the burner by means of one associated with the exhaust stream and upstream of the burner arranged second temperature measuring device and / or a control the injection quantity as a function of the measured further Actual temperature is provided. Advantageously, a feedforward control be realized, wherein the measured further actual temperature in a manipulated variable for controlling the amount of fuel is convertible.

at Another embodiment of the method is determining an actual exhaust gas mass flow characterizing the exhaust gas flow before Burner and / or controlling the injection quantity in dependence provided by the determined actual exhaust gas mass flow. Advantageous can be a feedforward for the regulation of the temperature can be realized, with the measured Actual exhaust gas mass flow in a control variable for controlling the injection quantity is convertible.

In a further embodiment of the Ver fahrens is a measuring of the secondary air mass flow characteristic actual secondary air mass flow means of a burner upstream air mass meter and / or setting a target secondary air mass flow and / or driving the flow limiting device in response to the predetermined target secondary air mass flow and the measured actual secondary air mass flow provided. Advantageously, a closed loop for the secondary air mass flow can be realized.

at Another embodiment of the method is measuring a first pressure of the secondary air mass flow before Flow limiting device by means of one of the flow limiting device upstream first pressure measuring device and / or a measuring a second pressure of the secondary air mass flow after the flow-limiting device by means of one of the flow-limiting device upstream second pressure measuring device and / or measuring a Pressure difference of the flow limiting device by means of a the flow-limiting device associated differential pressure measuring device and / or driving the flow-limiting device in dependence from the first pressure and the second pressure or the pressure difference provided the pressures. Advantageously, a feedforward control for the regulation of the secondary air mass flow will be realized. Advantageously, the measured pressures converted into an actuating movement of the flow limiting device become.

at Another embodiment of the method is determining of the exhaust gas flow characterizing actual exhaust gas mass flow and / or determining a space velocity of the exhaust gas treatment device and / or determining a flow of exhaust upstream the exhaust gas treatment device characteristic actual exhaust λ value and / or determining a desired injection quantity as a function of of at least one element of the following group: the actual exhaust gas mass flow, the space velocity, the actual exhaust λ value, the actual temperature and / or limiting the target injection quantity for keeping or exceeding a minimum exhaust λ value of the actual exhaust λ value intended. Advantageously, a closed loop for the temperature with a feedforward control the disturbances actual exhaust gas mass flow, space velocity and / or actual exhaust λ value can be realized. Advantageous In addition, it is possible to set the target injection quantity limit so that a minimum exhaust lambda value is maintained or can be exceeded. This can be, for example for a complete implementation of the combustion products of Burner by means of the residual oxygen contained in the exhaust stream and / or regeneration of a particulate filter useful be. For this purpose, the resulting actual exhaust λ value on a minimum value of> 1 be raised, so in any case to complete Implementation sufficient residual oxygen is present.

at Another embodiment of the method is a setting a minimum burner λ value of the burner and / or a Limiting the injection quantity as a function of the minimum burner λ value and / or limiting the injection quantity in dependence the actual secondary air mass flow and / or a limit the injection quantity falls below the minimum burner λ value intended. Advantageously, the burner can be parameterized that its exhaust gases are still an optimal composition for have a heating of the exhaust stream. So, for example an introduction of completely unburned fuel in the Exhaust gas flow by setting a minimum burner λ value be prevented.

at Another embodiment of the method is determining a desired injection quantity and / or setting a target burner λ value of the Burner and / or determining the desired secondary air mass flow depending on the determined target injection quantity and the desired burner λ value provided. The nominal burner λ value can specify a mixture formation of the burner. Advantageously a control and / or control of the desired burner λ value be realized, wherein the injection quantity is controlled and the Secondary air mass flow as manipulated variable or reference variable of the secondary air mass control acts.

at Another embodiment of the method is determining a desired stroke of a control valve of the flow limiting device and / or determining the desired stroke as a function of the predetermined Target secondary air mass flow and the measured actual secondary air mass flow and / or controlling a stroke of the control valve in dependence the actual hub and the desired hub provided. Advantageously, a Cascade controller can be realized, the desired stroke is a reference variable represent a valve regulator of the flow limiting device can. Accordingly, the desired hub of a parent Controller, such as a PI controller, the flow limiting device controls are determined. For this purpose, the flow-limiting device be configured as a control or servo valve.

The object is furthermore provided with an arrangement for setting a state of an exhaust gas flow, with an internal combustion engine generating the exhaust gas flow, with at least one exhaust gas treatment device through which the exhaust gas flow flows tion, at least one acting on the state of the exhaust gas flow control, at least one of the control associated with the measuring device for determining the state of the arrangement, in particular the exhaust gas flow, and dissolved acting on the state of the exhaust gas burner. The assembly is designed, constructed, and / or configured to perform a previously described method. This results in the advantages described above.

One Embodiment of the arrangement provides that the exhaust gas treatment device at least one element of the following group: an oxidation catalyst, a diesel oxidation catalyst, a particulate filter, a diesel particulate filter, a NOX storage catalyst, a three-way catalyst, an SCR catalyst (SCR = selective catalytic reduction). Advantageously, a Treatment of the exhaust gas for the purification of pollutants take place, wherein for example, for regeneration and / or desulfurization the exhaust treatment device, a thermal management of the exhaust stream can be done.

at a further embodiment of the arrangement is provided that the burner of the exhaust system is connected in parallel. In which Burner may be a so-called bypass burner, the exhaust gases in the main exhaust gas stream, such as this one leading exhaust system, dismisses. Advantageously obstructed thus the burner, if it is not needed, not the main exhaust stream.

at a further embodiment of the arrangement is provided that the internal combustion engine and the burner of a common pressure generating device assigned and can be supplied by means of this with fresh air. Advantageous is only a common pressure generating device or Compressed air source needed. A separate burner fan can be omitted.

Further Advantages, features and details emerge from the following Description, in reference to the drawing, an embodiment is described in detail. Same, similar and / or functionally identical parts are provided with the same reference numerals. Show it:

1 a schematic view of an arrangement for adjusting a state of an exhaust gas flow of an internal combustion engine of a motor vehicle;

2 a schematic representation of an overall control system for an exhaust gas burner;

3 a detailed representation of a controlled system of in 2 illustrated overall control system;

4 a detailed presentation of various functions of a temperature control of in 2 illustrated overall control system;

5 a representation of a cascade structure of a regulation of a secondary air mass flow of in 2 illustrated overall control system of the exhaust gas burner;

6 a schematic representation of an exhaust system of a motor vehicle associated partial flow burner; and

7 a section of the in 6 shown partial flow burner along the line AA.

1 shows a device 1 for adjusting a state of an exhaust gas flow 3 a partially illustrated internal combustion engine 5 a likewise only partially illustrated motor vehicle 7 , The internal combustion engine 5 is an exhaust system 9 with an exhaust system 11 downstream. About a suction pipe 13 becomes the internal combustion engine 5 supplied with air by means of a turbine 15 driven compressor 17 an exhaust gas turbocharger 19 is compressed. With a loading bucket adjustment 21 (VTG) can be the compression of the turbine 15 to be changed. The internal combustion engine 5 can an exhaust gas recirculation 23 (EGR), which is designed as high-pressure exhaust gas recirculation, with an exhaust gas recirculation valve 25 and an exhaust gas recirculation line 27 in which an exhaust gas recirculation cooler 29 is arranged. The exhaust gas of the exhaust gas flow 3 passes through an exhaust manifold 31 to the turbine 15 and in the exhaust system 9 or is in the exhaust manifold 31 in the exhaust gas recirculation 23 diverted.

The over a charge air cooler 33 cooled air or combustion air passes through a throttle valve 35 in an intake collector 37 , in which also the recirculated exhaust gas or a partial flow of the exhaust gas stream 3 empties. The charge pressure of the combustion air is with a charge air sensor 39 detected.

Fresh air or the combustion air passes through an air filter 41 and a fresh air mass sensor 43 to the compressor 17 and from there via a fresh air line 45 for guiding the combustion air or an air mass flow of the combustion air to the intercooler 33 , A control valve 47 controls the air supply via the fresh air line 45 ,

The compressor 17 the exhaust gas turbocharger 19 provides a compressed air source 49 for generating the air mass flow for supplying the internal combustion engine 5 with combustion air. The compressor 17 the compressed air source 49 downstream, the suction tube points 13 for guiding by means of the compressed air source 49 producible air mass flow a branch point 51 on, at the a secondary air line 53 branches. The secondary air line 53 is for branching a Se kundärluftmassenstroms 55 to supply a burner connected to it 57 designed with combustion air. It can be seen that both the burner 57 as well as the internal combustion engine 5 equally by means of the compressor 17 the compressed air source 49 can be supplied with combustion air. In 1 is the burner 57 symbolized by a triangle. At the burner 57 it is a the exhaust gas flow 3 of the exhaust system 9 the exhaust system 11 sibling burner, who at a junction 59 in the exhaust stream 3 empties. At the junction 59 dismisses the burner 57 a burner exhaust gas flow in the means of the exhaust line 9 guided exhaust gas flow 3 the internal combustion engine 5 , The burner can by means of a in 1 Not shown device with a fuel, preferably with the same fuel of the internal combustion engine 5 be supplied.

By means of the burner 57 can the fuel together with the secondary air mass flow 55 thermally reacted and for heating via the junction 59 in the exhaust stream 3 be dismissed. Preferably, the burner 57 be operated unteröometrometrisch, so with lack of air, so that the fuel only partially burned in the exhaust stream 3 is initiated. It can be advantageous in the exhaust gas flow of the internal combustion engine 5 to act on a lean exhaust stream, so that by means of the exhaust stream 3 existing residual oxygen a complete implementation of the burner 57 provided fuel can be made. The means of the burner 57 achievable increase in a temperature of the exhaust gas stream 3 can be advantageous for the regeneration of an exhaust gas purification device arranged downstream of the burner 61 the exhaust system 11 serve. In the exhaust gas purification device 61 For example, it may be a particulate filter, preferably a diesel particulate filter 63 , act. For better and / or complete implementation of only partially burned fuel of the burner 57 can the particle filter 63 an oxidation catalyst 65 , In particular, a diesel-oxidation catalyst and a mixer, not shown. Alternatively and / or additionally, it is possible for the particle filter 63 to precede a separate diesel oxidation catalyst.

The particle filter 63 is remote engine in the exhaust system 9 the internal combustion engine 5 arranged. Advantageously, without major thermal losses only by means of the burner 57 a quick heating of the particle filter 63 to its regeneration done. Advantageously, the amount of fuel required for this can be kept to a minimum. Optionally, additional temperature-increasing measures can be carried out.

Alternatively, in particular for a thermal management of the exhaust system 11 , it is possible to use several of the burners 57 in the exhaust system 11 provided. Besides, it is possible to use the burner 57 or the point of confluence 59 of the burner 57 at another location of the exhaust system 11 provide, for example, in front of an SCR catalyst 67 , in front of a NOX storage catalytic converter 69 and / or in front of a close-coupled, oxidation catalyst 71 , In 1 are exemplary of the oxidation catalyst 71 close to the engine, this is followed by the NOX catalyst 69 and this downstream of the SCR catalyst 67 the exhaust system 11 shown.

In the internal combustion engine 5 it can be a lean exhaust stream 3 producing internal combustion engine act, for example, a diesel engine or a lean-burn engine with spark ignition.

In the secondary air line 53 can be an air mass meter 73 be switched. By means of the air mass meter 73 can the secondary air mass flow 55 be determined. To do this, the air mass meter 73 For example, be designed as a hot wire anemometer and / or as an ultrasonic Doppler anemometer.

Between the air mass meter 73 and the branch office 51 is the secondary air line 53 dashed lines to indicate that the secondary air mass flow 55 can be generated in any manner, for example by means of the exhaust gas turbocharger 19 , A non-illustrated compressor, a Komprex-charger not shown in detail and / or a combination of a compressor and a likewise not shown compressed air reservoir of the compressed air source 49 ,

2 shows a block diagram of a total control system 75 a burner 57 , By means of the burner 57 may be a state of exhaust gas flow 3 be set.

3 shows a detail of a controlled system 77 of in 2 illustrated overall control system 75 , The system boundaries are symbolized by dashed lines. The following is the description of the overall control system on the 2 and 3 referred to together.

The controlled system 77 includes the sibling burner 57 that exhausts its exhaust via the confluence point 59 in a pipe section 79 of exhaust system 9 the exhaust system 11 of the motor vehicle 7 dismisses. The one in the pipe section 79 guided exhaust gas flow 3 is by means of an arrow 81 symbolizes and flows, in alignment with the 2 seen, from left to right. Optionally, in the pipe section 79 a mixer 83 for eliminating inhomogeneities of the exhaust gas flow 3 be provided. Under mixer in the broadest sense, only the pipe section 79 be understood. The mixer may be, for example, a static mixer, for example the exhaust gas flow 3 may have turbulent plates.

The pipe section 79 is the diesel oxidation catalyst 65 downstream, which deviates from the illustration according to 1 is carried out separately. Not shown in detail, the oxidation catalyst 65 the particle filter 63 be followed. Advantageously, the particle filter 63 with the means of the overall control system 75 adjustable exhaust gas flow 3 , For example, to a regeneration, are applied.

By means of the overall control system 75 can be a state of exhaust gas flow 3 be set, for example, a temperature 85 after the diesel oxidation catalyst 65 the exhaust gas purification device 61 having. To determine the temperature 85 the exhaust stream 3 after the diesel oxidation catalyst 65 identifying actual temperature 87 is the exhaust gas flow 3 a first measuring device 89 associated with a temperature measuring device assigned. The first measuring device 89 can have any temperature sensor. The first measuring device 89 is a first regulator 91 downstream. The first controller 91 can be the actual temperature 87 and a target temperature 93 process and from this a first manipulated variable 95 to calculate. The first controller 91 may be a P, I and / or D component for determining the first manipulated variable 95 exhibit. In front of the burner 57 indicates the exhaust gas flow 3 another temperature 97 on, wherein by means of a second, the exhaust gas flow 3 and the burner 57 upstream assigned measuring device 99 having a temperature measuring device, one the further temperature 97 characteristic further actual temperature 101 can be determined. The further actual temperature 101 becomes a feedforward control 103 fed, the resulting second control variable 105 calculated. At an addition point 107 become the first manipulated variable 95 and the second manipulated variable 105 to a fuel control variable 109 added. The fuel control variable 109 controls a fuel valve 111 at. The fuel valve 111 is between a fuel tank 113 and the burner 57 switched and used to control an injection quantity 115 by means of the fuel tank 113 provided fuel in the burner 57 ,

At the fuel tank 113 it can also be the internal combustion engine 5 trading fuel tank. However, it is also conceivable the fuel tank 113 separated from further energy storage of the internal combustion engine 5 provide, for example, a lighter flammable fuel the burner 57 to provide.

For thermal conversion of the injection quantity 115 becomes the burner 57 a secondary air mass flow 117 fed. By means of a third measuring device 119 , which has an air mass measuring device is a secondary air mass flow 117 identifying actual secondary air mass flow 121 measurable. The actual secondary air mass flow 121 can be a second regulator 123 be supplied. In addition, the second regulator is added 123 a desired secondary air mass flow 125 specified. The controller can be determined from the measured actual secondary air mass flow 121 and the desired secondary air mass flow 125 a third manipulated variable 127 determine. To determine the third manipulated variable 127 can the second controller 123 have a P, I and / or D content.

The secondary air mass flow 117 is by means of the compressed air source 49 , for example, a compressed air storage 129 can be generated, generated. Between the compressed air reservoir 129 and the burner 57 is a flow restriction device 131 connected. The flow restriction device 131 For example, a control valve 133 exhibit. The flow-limiting device 131 is upstream and downstream of a differential pressure measuring device 135 assigned a first pressure 137 , P _v before the flow limiting device and a second pressure 139 , P _n , after the flow-limiting device 131 measure and from this a pressure difference 141 can derive. The pressure difference 141 becomes a control unit 143 made available. In addition, the control unit 143 the desired secondary air mass flow 125 made available. The control unit 143 can realize a combination of a feedforward control and a stationary pilot control, ie from the pressure difference 141 and the desired secondary air mass flow 125 a fourth manipulated variable 145 derived. At a second addition point 147 become the third manipulated variable 127 and the fourth manipulated variable 145 in a nominal stroke 149 added. By means of the nominal stroke 149 can the control valve 133 the flow restriction device 131 be controlled, so that ultimately the secondary air mass flow 117 to control.

The overall control system 75 So has a closed loop for the temperature 85 and for the secondary air mass flow 117 on.

In 3 are on the controlled system 77 Act de Disturbance variables of the temperature control loop with the controlled variable of the temperature 85 clarified. As disturbances act, in the representation of 3 from left to right, the further temperature 97 the exhaust stream 3 and an exhaust gas mass flow 151 the exhaust stream 3 , the secondary air mass flow 117 , a forced convection 153 and / or a free convection 155 , The forced convection 153 For example, by means of a wind with moving motor vehicle 7 that the exhaust tract 9 swept over, be evoked. For not affected by the wind of parts of the exhaust system 9 of the motor vehicle 7 it may come to heat transfer by means of free convection.

4 shows a detailed block diagram of various functions of the in the 2 and 3 shown temperature control of the overall control system 75 ,

As in 4 can be seen, the feedforward 103 additionally with the exhaust gas mass flow 151 or with a measured, this characterizing actual exhaust gas mass flow 161 be applied to this disturbance in the second manipulated variable 105 to be included.

The fuel mass or the injection quantity 115 is the manipulated variable in temperature control. It is composed of the feedforward control 103 and a regulator portion of the regulator 91 ,

In the disturbance variable connection 103 In addition to measurable disturbance variables, known heat losses due to free convection can also occur 155 and / or radiation.

Non-measurable disturbances can be compensated by the control, this includes in particular the forced convection 153 , Inaccuracies of the measuring equipment, inaccuracies of the actuators and / or variable characteristics of the burner 57 supplied fuel.

Advantageously, in addition to the temperature control, as in 4 shown, for- a regeneration of the particulate filter 63 a limitation of the burner λ value to the minimum burner λ value 173 respectively. Advantageously, thereby HC breakthroughs after the particulate filter 63 and thus undesirable emissions are avoided while providing sufficient residual oxygen for oxidation of the soot.

As in 4 is the first addition point 107 a subtraction point 157 downstream. The subtraction point 157 serves to reduce the fuel control variable 109 to thereby create a minimum λ of the burner 57 to be able to guarantee. This is the subtraction point 157 a third controller 159 upstream, which calculates a minimum λ-actuator size and thus the fuel control variable 109 so limited that a minimum λ value of the burner 57 is sustainable. To do this, the third controller 159 for billing the actual temperature 87 , one the exhaust gas mass flow 151 characteristic actual exhaust gas mass flow 161 , a space velocity 163 as they are within the diesel oxidation catalyst 65 prevails and / or an actual λ exhaust gas value 165 with the burner exhaust gases of the burner 57 mixed exhaust gas flow 3 downstream of the diesel oxidation catalyst 65 or upstream of the particle filter to be regenerated 63 be supplied.

The subtraction point 157 is a first limitation 167 or limiting and monitoring connected downstream, for example, a shutdown of the fuel supply of the burner 57 in the case of non-plausible operating conditions. By means of the first limitation 167 can be a target injection quantity 169 to be generated. This target injection quantity 169 may be a second limitation 171 be supplied, which is the actual secondary air mass flow 121 and a minimum burner λ value 173 can be fed. After the second limitation 171 results in a second target injection quantity 175 that instead of in 2 illustrated fuel control variable 109 can be used to control the fuel valve.

The not by means of the second limitation 171 limited first target injection quantity 169 can a calculation 177 be supplied. The calculation 177 can still have a nominal burner λ value 179 be supplied. By calculation 177 can be the first target injection quantity 169 and the target burner λ value 179 in the desired secondary air mass flow 125 be converted.

Downstream, the secondary air mass control takes place, the setpoint as the manipulated variable 149 generated.

The target stroke 149 serves as a reference variable for a fourth controller 181 of the control valve 131 the flow restriction device 131 for controlling the secondary air mass flow 117 , what in 5 is shown in detail.

5 shows a cascade structure of the secondary air control with the second controller 123 and a fourth controller cascaded thereto 181 ,

A controlled system 183 of in 5 shown cascade controller has the control valve 133 and this is followed by an air gap 185 on. To control a hub 187 of the control valve 133 who is on the air route 185 acts, can be an actual hub 189 be determined and the fourth PI controller 181 , in particular as one of the desired stroke and the actual stroke 189 calculable stroke deviation, be provided.

The 6 and 7 show an embodiment of the burner 57 with a burner housing 201 in a supervisory and cross-sectional view.

The burner 57 preferably has an injection device 203 for the fuel and a mixing chamber 202 for mixing fuel and air or exhaust gas.

6 shows a schematic representation of a burner 57 , by means of the junction 59 Burner gases in the means of the exhaust line 9 of the motor vehicle 7 guided exhaust gas flow 3 dismisses.

7 shows a sectional view of the in 6 shown burner 57 along the line AA.

The over the injector 203 in the burner 57 introduced fuel enters the, preferably outside the exhaust line 9 placed mixing chamber 203 of the burner 57 and is mixed with the air supplied to the burner (or a partial exhaust gas stream) such that a combustible gas is generated in the mixing chamber. This can preferably be achieved by a tangential inflow 205 the air into the mixing chamber 202 be achieved. The activation energy for igniting the combustible mixture can be achieved via a suitable ignition device (or annealing device) arranged in the mixing chamber. 204 be generated.

The burner 57 is operated with a substoichiometric combustion air ratio λ = 0.1 to 0.95, preferably λ = 0.25 to 0.9, more preferably λ = 0.35 to 0.75. The combustion air ratio λ is controlled by an oxygen control of the burner 57 set. For this purpose, a corresponding unit is provided for regulating and / or controlling the combustion air ratio λ (not shown).

In a flow direction 60 the exhaust stream downstream of the burner 57 and upstream of the at least temporarily to be regenerated exhaust gas purification device 58 is optional a facility 56 arranged for flame stabilization. Furthermore, it is optional in the burner 57 An institution 206 arranged for flame stabilization.

Depending on the required burner output, the introduced fuel is completely or only partially thermally converted in the burner, possibly in the mixing chamber. During a predetermined time interval of more than 100 seconds at least 10%, preferably 20%, more preferably 20% of the burner 57 amount of fuel supplied downstream in one or more exhaust purification devices or a part of the exhaust line 9 implemented.

at higher power requirement for regeneration thus arrives targeted a higher proportion of unburned fuel in the exhaust mainstream and is only there and in particular in a or more downstream exhaust purification devices oxidized.

Advantageously, a Untertöcheometrischer operation of the burner 57 with a controlled burner output and an adjustable combustion air ratio for the regeneration of the remote particle filter 63 be used. Advantageously, if the burner 57 operated sub-secheometrically, only part of the burner 57 introduced fuel are burned. The other part of the fuel is partially burned and a main flow of the exhaust stream 3 over the junction 59 fed. The partially burned portion of the fuel in the burner 57 , due to the Untertoecheometrischen burner operation not in the burner 57 burns, is fully implemented in the exhaust main stream, since advantageously in the exhaust main stream sufficient oxygen is present for complete reaction. It is advantageous that the mixture preparation in the burner 57 is better than, for example, in a simple external fuel metering in the exhaust system 9 in that the partially oxidized fuel components due to the bottom -ochemical burner operation are very reactive and can therefore be converted particularly well in the main exhaust stream even under unfavorable boundary conditions such as a low temperature and / or high space velocity, and that advantageous reactant control is possible by a λ-controlled burner operation. Gases, such. B. CO and / or H2 for further exhaust aftertreatment in the exhaust system 9 can be dosed.

The combustion air ratio or the burner λ value can be advantageously set by means of a controlled oxygen supply. The combustion air ratio may be controlled in a target range of λ = 0.25 to 0.9, preferably 0.35 to 0.75. The λ-value can be adjusted by means of the oxygen control independently of a heating power of the burner, since advantageously a variation not by means of fuel, but on the air side, in particular by means of the control loop of the secondary air mass flow 117 he follows ( 4 ).

With the help of the λ-control of the burner 57 can also be advantageous in the main exhaust stream of the exhaust stream 3 introduced heating energy to be controlled. In this way, for a filter regeneration of the particulate filter 63 necessary burnup temperature can be set and / or regulated particularly accurately. Advantageously, a balanced temperature level results without dynamic temperature peaks, a better overall efficiency, a safe operation of the internal combustion engine 5 independent filter regeneration and / or consumption savings.

A secondary air supplying the burner with the secondary air mass flow 117 can be done in any manner, for example by means of a secondary air pump or via a compressor or Abgasabgriff the turbocharger 19 the internal combustion engine 5 ,

Advantageously, the burner 57 in addition to a regeneration of the particulate filter 63 for temperature control of the entire exhaust system 11 of the motor vehicle 7 , be used as so-called exhaust gas temperature management. For this purpose, the burner 57 anywhere in the exhaust system 11 to be ordered. Advantageously, even for such use of the burner 57 a necessary fuel for the exhaust gas temperature management and / or the regeneration of the particulate filter 63 be reduced.

Advantageously, the burner 57 Subcheometrically with a controlled burner power and an adjustable combustion air ratio or burner λ value, in particular for a regeneration of the remote engine particulate filter 63 be used.

Advantageously, the burner λ value by means of the oxygen control or the control of the secondary air mass flow 117 regardless of the heat output of the burner 57 be set because advantageous this variation is not by means of a variation of the injection quantity 115 he follows.

Advantageously, thereby also a in the exhaust stream 3 introduced heating energy can be controlled, which advantageously for a filter regeneration of the particulate filter 63 necessary burnup temperature or temperature 85 can be precisely adjusted and regulated.

In an advantageous embodiment of the exhaust system 11 can the SCR catalyst 67 in front of the burner 57 and this before the remote engine diesel oxidation catalyst 65 lie.

Advantageously, optionally, the injection quantity 115 or the secondary air mass flow 117 kept constant. In combination both sizes can be varied.

It is conceivable the burner 57 as an exhaust-powered burner and in front of the NOX storage catalytic converter 69 and / or before the SCR catalyst 67 to arrange. It is conceivable on the catalysts 69 or 67 to dispense or only one of the catalysts 69 or 67 in the exhaust system 11 provided.

Advantageously, the burner 57 also for an improvement of the cold start behavior of the internal combustion engine 5 be used.

Finally, it is conceivable, after the burner 57 the diesel oxidation catalyst 65 or 71 to arrange.

The actual required secondary air mass flow 117 depends on the operation of the burner 57 from the injection quantity 115 from. The secondary air mass flow 117 may be between 5-15%, preferably 10%, of the total exhaust gas mass flow of the exhaust stream 3 be. A precise amount of secondary air mass flow 117 can by means of the formula m SL = λ BK × L St × m Krst be calculated. In this case, m _SL corresponds to the secondary air mass flow 117 , λ _BK the burner λ-value of the burner 57 , L _{St of} a stoichiometric air mass per amount of fuel and m _Krst the injection quantity 115 as mass flow.

1

contraption

3

exhaust gas flow

5

Internal combustion engine

7

motor vehicle

9

exhaust gas line

11

exhaust system

13

suction tube

15

turbine

17

compressor

19

turbocharger

21

Bucket adjustment

23

Exhaust gas recirculation

25

Exhaust gas recirculation valve

27

Exhaust gas recirculation line

29

Exhaust gas recirculation cooler

31

exhaust manifold

33

Intercooler

35

throttle

37

intake manifold

39

Charge air sensor

41

air filter

43

Fresh air mass sensor

45

Fresh air line

47

control valve

49

Compressed air source

51

branching point

53

Secondary air line

55

Secondary air mass flow

57

burner

59

junction point

61

exhaust gas cleaning device

63

Diesel Particulate Filter

65

oxidation catalyst

67

SCR catalyst

69

NOX storage catalyst

71

oxidation catalyst

73

Air flow sensor

75

Total control system

77

controlled system

79

pipe section

81

arrow

83

mixer

85

temperature

87

Actual temperature

89

first measuring device

91

first regulator

93

Target temperature

95

first manipulated variable

97

temperature

99

second measuring device

101

Actual temperature

103

feedforward

105

second manipulated variable

107

addition site

109

Fuel control value

111

Fuel valve

113

Fuel tank

115

Injection quantity

117

Secondary air mass flow

119

third measuring device

121

Actual secondary air mass flow

123

second regulator

125

Target secondary air mass flow

127

third manipulated variable

129

Compressed air storage

131

Flow limiting device

133

control valve

135

Differential pressure measuring device

137

first print

139

second print

141

pressure difference

143

control unit

145

fourth manipulated variable

147

second addition site

149

Target stroke

151

Exhaust gas mass flow

153

convection

155

free convection

157

subtraction

159

third regulator

161

Actual exhaust gas mass flow

163

space velocity

165

Actual λ exhaust value

167

limitation and monitoring

169

Target injection quantity

171

second limitation

173

Minimum burner λ-value

175

second Target injection quantity

177

calculation

179

Target burner λ-value

181

fourth regulator

183

controlled system

185

air gap

187

stroke

189

Is Hub

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102004022186 [0002]
• - DE 4443133 A1 [0002]
• - DE 3837472 A1 [0003]
• - DE 102006009943 A1 [0004]

Claims (18)

Method for setting a state of an exhaust gas flow ( 3 ) an internal combustion engine ( 5 ) of a motor vehicle ( 7 ) with one of the internal combustion engine ( 5 ) downstream of the exhaust stream ( 3 ) through-flow exhaust system ( 11 ) by means of a flow of exhaust gas ( 3 ) associated burner ( 57 ), with - controlled or regulated feeding of an injection quantity ( 115 ) of a fuel in the burner ( 57 ), - Controlled or regulated feeding of a secondary air mass flow ( 117 ) in the burner ( 57 ), one being derived from the injection quantity ( 115 ) and the secondary air mass flow ( 117 ) resulting burner λ value is less than 1. The method of claim 1, comprising at least one of following: - Where the burner λ value more is 0.25 and less than 0.9, - in which the burner λ value is more than 0.35 and less than 0.75, Method according to one of the preceding claims, with at least one of the following: setting the burner λ value with constantly supplied injection quantity ( 115 ) by controlling the secondary air mass flow ( 117 ), - setting the burner λ value at a constant supplied secondary air mass flow ( 117 ) by controlling the injection quantity ( 117 ), - adjusting the burner λ value by controlling the injection quantity ( 115 ) and the secondary air mass flow ( 117 ). Method, in particular according to one of the preceding claims, for setting a state of an exhaust gas flow ( 3 ) an internal combustion engine ( 5 ) of a motor vehicle ( 7 ) with one of the internal combustion engine ( 5 ) downstream of the exhaust stream ( 3 ) through-flow exhaust system ( 11 ) with an exhaust gas treatment device ( 61 ) by means of a flow of exhaust gas ( 3 ) associated burner ( 57 ), with: - controlling a temperature ( 85 ) of the exhaust gas stream ( 3 ) after the exhaust treatment device ( 61 ) by controlling a burner ( 57 ) deliverable injection quantity ( 115 ) of a fuel, - controlling a burner ( 57 ) deliverable secondary air mass flow ( 117 ) by controlling one of the secondary air mass flow ( 117 ) throughflow limiting device ( 131 ). Method according to one of the preceding claims, comprising at least one of the following: - generating the secondary air mass flow ( 117 ) by means of a compressed air source ( 49 ), - generating the secondary air mass flow ( 117 ) by means of the flow-limiting device ( 131 ) upstream compressed air source ( 49 ), - generating the secondary air mass flow ( 117 ) and supplying the internal combustion engine ( 5 ) with combustion air by means of the compressed air source ( 49 ), which comprises at least one element of the following group: - a compressor ( 17 ), - an exhaust gas turbocharger ( 19 ), - a compressor, - a Komprex charger, - a compressed air reservoir ( 129 ). Method according to one of the preceding claims, comprising at least one of the following: measuring a temperature ( 85 ) indicative actual temperature ( 87 ) of the exhaust gas stream ( 3 ) after the exhaust treatment device ( 61 ) by means of a flow of exhaust gas ( 3 ) and the exhaust gas treatment device ( 61 ) downstream first measuring device ( 89 ), in particular temperature measuring device, - Specifying a desired temperature ( 93 ), - controlling the injection quantity ( 115 ) as a function of the predetermined target temperature ( 93 ) and the measured actual temperature ( 87 ). Method according to one of the preceding claims, with at least one of the following: measuring a further actual temperature ( 101 ) of the exhaust gas stream ( 3 ) in front of the burner ( 57 ) by means of a flow of exhaust gas ( 3 ) and the burner ( 57 ) arranged upstream second measuring device ( 99 ), in particular temperature measuring device, - controlling the injection quantity ( 115 ) as a function of the measured further actual temperature ( 101 ). Method according to one of the preceding claims, with at least one of the following: determining a flow of exhaust gas ( 3 ) characteristic actual exhaust gas mass flow ( 161 ) in front of the burner ( 57 ), - controlling the injection quantity ( 115 ) in dependence on the determined actual exhaust gas mass flow ( 161 ). Method according to one of the preceding claims, comprising at least one of the following: measuring a secondary air mass flow ( 117 ) indicative actual secondary air mass flow ( 121 ) by means of a burner ( 57 ) upstream third measuring device ( 119 ), in particular air mass measuring device, - predetermining a desired secondary air mass flow ( 125 ), - controlling the flow-limiting device ( 131 ) in dependence on the predetermined desired secondary air mass flow ( 125 ) and the measured actual secondary air mass flow ( 121 ). Method according to one of the preceding claims, comprising at least one of the following: measuring a first pressure ( 137 ) (P _V ) of the secondary air mass flow ( 117 ) in front of the flow-limiting device ( 131 ) by means of one of the flow-limiting device ( 131 ) upstream first pressure measuring device, - measuring a second pressure ( 139 ) (P _n ) of the secondary air mass flow ( 117 ) after the flow restriction device ( 131 ) by means of one of the flow-limiting device ( 131 ) downstream second pressure measuring device, - measuring a pressure difference ( 141 ) of the flow-limiting device ( 131 ) by means of one of the flow-limiting device ( 131 ) associated differential pressure measuring device ( 135 ), - controlling the flow-limiting device ( 131 ) depending on the first pressure ( 137 ) (P _V ) and the second pressure ( 139 ) (P _n ) or the pressure difference ( 141 ) of the pressures ( 137 . 139 ). Method according to one of the preceding claims, with at least one of the following: determining the exhaust gas flow ( 3 ) characteristic actual exhaust gas mass flow ( 161 ), - determining a space velocity ( 163 ) of the exhaust gas treatment device ( 61 ), - determining the exhaust gas flow ( 3 ) upstream of the exhaust treatment device ( 61 ) characteristic actual exhaust λ value ( 165 ), - determining a desired injection quantity ( 169 ) depending on at least one element of the following group: the actual exhaust gas mass flow ( 161 ), the space velocity ( 163 ), the actual exhaust λ value ( 165 ), the actual temperature ( 87 ), - limiting the target injection quantity ( 169 ) for maintaining or exceeding a minimum exhaust gas λ value of the actual exhaust gas λ value ( 165 ). Method according to one of the preceding claims, comprising at least one of the following: - determining a minimum burner λ value ( 173 ) of the burner ( 57 ), - limiting the injection quantity ( 115 ) as a function of the minimum burner λ value ( 173 ), - limiting the injection quantity ( 115 ) as a function of the actual secondary air mass flow ( 121 ), - limiting the injection quantity ( 115 ) falls below the minimum burner λ value ( 173 ). Method according to one of the preceding claims, with at least one of the following: determining a nominal injection quantity ( 169 ), - setting a desired burner λ value ( 179 ) of the burner ( 57 ), - determining the desired secondary air mass flow ( 125 ) as a function of the determined nominal injection quantity ( 169 ) and the desired burner λ value ( 179 ). Method according to one of the preceding claims, with at least one of the following: determining a desired hub ( 149 ) a control valve ( 133 ) of the flow-limiting device ( 131 ), - determining the desired hub ( 149 ) in dependence on the predetermined target secondary air mass flow ( 125 ) and the measured actual secondary air mass flow ( 121 ), - determining an actual hub ( 189 ) of the control valve ( 133 ) - controlling a hub ( 187 ) of the control valve ( 133 ) depending on the actual hub ( 189 ) and the desired hub ( 149 ). Arrangement for setting a state of an exhaust gas flow ( 3 ), with - one the exhaust gas flow ( 3 ) generating internal combustion engine ( 5 ), At least one of the exhaust gas flow ( 3 ) through the exhaust treatment device ( 61 ), - at least one on the state of the exhaust stream ( 3 ) acting control, - at least one of the control associated with measuring device for determining the state of the arrangement, in particular the exhaust stream ( 3 ), - one on the state of the exhaust stream ( 3 ) acting burner ( 57 ), designed, constructed and / or arranged for carrying out a method according to one of the preceding claims. Arrangement according to claim 16, wherein the exhaust gas treatment device ( 61 ) at least one element of the following group: - an oxidation catalyst ( 65 ), - a diesel oxidation catalyst ( 65 . 71 ), - a particulate filter ( 63 ), - a diesel particulate filter ( 63 ), - a NOX storage catalyst ( 69 ), - a three-way catalyst, - an SCR catalyst ( 67 ). Arrangement according to one of claims 16 or 17, wherein the burner ( 57 ) the exhaust line ( 9 ) is connected in parallel. Arrangement according to one of the preceding claims 16-18, wherein the internal combustion engine ( 5 ) and the burner ( 57 ) of a common compressed air source ( 49 ) are assigned and supplied by means of this with fresh air.