SE1351159A1 - Regulation of a concentration / fraction of constituents in an exhaust stream - Google Patents

Abstract

The present invention relates to a method for controlling a concentration / fraction of one or more constituents in an exhaust stream in a motor vehicle by controlling its driveline, which motor vehicle comprises: a driveline comprising an internal combustion engine coupled to a continuously variable gearbox (CVT / IVT) via a coupling device, and an exhaust system arranged to divert an exhaust stream from said internal combustion engine, said method comprising the step of: - controlling said continuously variable gearbox (CVT / IVT), and thus an operating point of said internal combustion engine, based on said first parameters P1. regulating a concentration / fraction C Ex / X Ex of one or fl your constituents in said exhaust gas stream, wherein at least one of said one or fl your first parameters P1 is a first concentration / fraction difference between said fast concentration / fraction C1 / X1 in said exhaust stream and a reference concentration / fractionC Re f / X Re f. Further refers to the invention comprises a computer program, a computer program product, a system and a motor vehicle comprising such a system. (Fig. 1)

Description

10 15 20 25 30 chemical reactor together with a precious metal coating in the diesel oxidation catalyst.

Said diesel oxidation catalyst is normally used primarily to oxidize the residue hydrocarbons and carbon monoxide in the exhaust stream to carbon dioxide, water and heat, as well as conversion of nitrogen monoxide to nitrogen dioxide.

During the combustion of fuel in the combustion chamber (cylinders) of the internal combustion engine, soot particles. For this reason, particulate filters are used to capture soot particles and works in such a way that the exhaust stream is led through a filter structure where soot particles are captured from the passing exhaust stream and is stored in the particulate filter. The particle filter is filled with soot as the vehicle is driven and sooner or later the filter must be emptied of soot, which usually accomplished by means of so-called regeneration. Said regeneration means that the soot particles (mainly carbon particles) are converted to carbon dioxide and / or carbon monoxide in a or fl your chemical processes. Regeneration can take place in different ways and can, for example, take place with with the help of so-called NOg-based regeneration is often also called passive regeneration, or by s.k. oxygen (O2) -based regeneration also called active regeneration.

In passive regeneration, nitric oxide and carbon monoxide are formed in a reaction between carbon and carbon dioxide nitrogen dioxide according to e.g. Equation 1: NO2 + C = NO + CO (1) However, passive regeneration is strongly dependent on the availability of nitrogen dioxide. If the supply of nitrogen dioxide is reduced, the regeneration rate will also be reduced.

The supply of nitrogen dioxide can e.g. reduced if the formation of nitrogen dioxide is inhibited, which for example can occur if one or fl your components in the finishing system are poisoned by sulfur which normally occurs in at least certain types of fuels, such as e.g. Diesel. Also competing chemical reactions inhibit the conversion of nitrogen dioxide.

The advantage of passive regeneration is that desired reaction rates and hence it speed at which the filter is emptied is reached at lower temperatures. Typically, regeneration takes place particulate filter for passive regeneration at temperatures in the range 200 ° C - 500 ° C, although temperatures in the high part of the range are normally preferable. Whatever this constitutes thus this compared with active regeneration significantly lower temperature range a great advantage at for example the presence of SCR catalysts because there is no risk of such a thing happening high temperature level is achieved that the risk of the SCR catalyst being damaged. It still is, though 10 15 20 25 30 It is important that a relatively high temperature is obtained for efficient passive regeneration can happen.

During active regeneration, s.k. oxygen (O2) -based regeneration, a chemical process takes place in mainly according to equation 2: C + Og = C02 + heat (2) Thus, during active regeneration, carbon plus oxygen is converted to carbon dioxide plus heat. This however, chemical reaction is highly temperature dependent and requires relatively high filter temperatures in order for a significant reaction rate to occur at all. Typical a minimum particle filter temperature of 500 ° C is required, but preferably the filter temperature should be be even higher for the regeneration to take place at the desired speed. The reaction rate for chemical reactions, e.g. the reactions of equations 1 and 2 above are also dependent on the concentration of reactants. For example, if the concentration of any reactant is low, it becomes the reaction rate was low, and if the reactant is completely absent, no reaction occurs at all.

However, the maximum temperature that can be used for active regeneration is often limited tolerances for some of the components of the after-treatment system / exhaust system.

For example. has o fi a particulate filter 202 and / or (where applicable) a subsequent SCR catalyst design limitations with respect to the maximum temperature these may be exposed to. This means that the active regeneration can have a component-wise maximum permissible temperature which is usually undesirably low. At the same time, therefore, a very high is required minimum temperature for any useful reaction rate to occur at all. At the active regeneration normally burns the soot load in the particle filter 202 substantially completely. That is, a total regeneration of the particle filter is obtained, after which the soot level in the particle filter is essentially 0%. Today, it is increasingly common for vehicles in addition to particulate filters 202 are also equipped with SCR catalysts 201, so that the active regeneration can result problems in the form of overheating for the subsequent SCR catalyst treatment process.

It is therefore of the utmost importance to be able to stop a rapidly increasing temperature of the exhaust gases before SCR catalyst. Such a rapidly increasing temperature can e.g. due to a rampant oxidation in the particulate filter (DPF), which can be inhibited or stopped if the concentration of oxygen enters to the particle filter is reduced to a low or non-existent level. However, as mentioned above, it is also 10 15 20 25 30 It is important that the temperature is regulated at other components in the exhaust system, such as to prevent or inhibit local or global overtemperature particle filter (DPF), etc.

Depending on how a vehicle is driven, the concentration / fraction of it will increase the combustion resulting the exhaust gas flow to vary. If the internal combustion engine is working hard the exhaust gas flow will maintain a higher concentration / fraction of combustion products and lower concentrations / fractions of combustion reactants and vice versa about the load on the internal combustion engine is relatively low, the concentration / fraction of the exhaust gas will to be essentially the reverse. If the vehicle is driven for a long time in such a way that the exhaust gas stream contains relatively high concentrations / fractions of undesirable combustion products, such as e.g. sulfur oxides, comes a degradation of the function of the diesel oxidation catalyst 205 fi to occur due to the fact that in the fuel reaction of the sulfur in various forms with the active of the diesel oxidation catalyst 205 coating, usually comprising one or more precious metals or other applicable metals such as e.g. aluminum. These problems usually occur at low (150 ° C) to medium high (300 ° C) temperatures. At temperatures below 150 ° - 250 ° C inger for example not SCR catalysts well. On the other hand, if the vehicle is driven for a long time on one such a way that the temperature of the exhaust stream maintains relatively high temperatures means that that active regeneration can take place at the desired speed. However, the temperature does not get in the exhaust gas flow exceeds a maximum permissible temperature so that heat-sensitive components in the finishing system is damaged as previously mentioned. It is then especially important to ensure that the concentration of NOX is kept at low levels and that the NO2 / NOX balance is optimal.

The concentration C of a substance in a gas can be expressed according to the equation: C = N / V, where N indicates the number of molecules of a given substance and the V volume, i.e. the number of molecules of a given substance in a given volume. The total concentration CTÛt, which increases in an ideal gas if the pressure increased and the temperature decreases, is given by the general gas law such as CTot = NTOt / V, where NTot indicates the total number of molecules. Regarding the fraction X of a substance, it is given by the relation between the concentration C and the fraction X according to: C = X - CTO, If no chemical reactions does not change the fraction that indicates the proportion of molecules in a volume belonging to a particular substance unless additional molecules are mixed with the original volume. This can e.g. happen by diffusion and / or by mixing gas elements by so-called turbulence. The new 10 15 20 25 30 the molecules that are mixed in can e.g. come from injected into the exhaust pipe, and possibly evaporated or reacted urea and / or diesel. They can also come from previously stored substances that are released, e.g. condensed water drawn with the exhaust stream and / or evaporated.

Examples of substances in the exhaust system that can be regulated are: carbon monoxide (CO) and nitrogen oxide (NO) which react e.g. with oxygen to carbon dioxide (CO2) and nitrogen dioxide (NO2) respectively.

Brief description of the invention An object of the present invention is to provide a solution which completely or partially solves problems and / or disadvantages with solutions for regulating a concentration / fraction of one or more constituents in an exhaust gas stream according to the prior art.

According to a first aspect of the invention, the above-mentioned object is achieved by a method for regulation of a concentration / fraction of one or fl of your constituents in an exhaust gas stream in one motor vehicle by controlling its driveline, which motor vehicle comprises: a driveline comprising an internal combustion engine connectable to a continuously variable gearbox (CVT / IVT) via a coupling device, and an exhaust system arranged to divert a exhaust gas from said internal combustion engine; said method comprising the step of: control of said continuously variable gearbox (CVT / IVT), and thus a operating point of said internal combustion engine, based on said one or fl your first parameters P1 for control of a concentration / fraction CEx / XEX of one or fl are included substances in said exhaust stream, wherein at least one of said one or fl is your first parameters P1 is a first concentration / fraction difference between said first concentration / fraction Cl / X1 in said exhaust gas stream and a reference concentration / fraction C Re f / X Re f.

Various embodiments of the method above are defined in the dependent appendices to the method patent claims. A method according to the invention can furthermore be implemented in a computer program, Which when executed in a computer causes the computer to perform the method of the invention.

According to a second aspect of the invention, the above-mentioned object is achieved with a system arranged for controlling one or more of your functions in a motor vehicle, which motor vehicle comprises: a driveline comprising an internal combustion engine connectable to a continuous variable gearbox (CVT / IVT) via a coupling device, and an exhaust system arranged for 10 15 20 25 30 dissipating an exhaust stream from said internal combustion engine; wherein said system comprises a control unit arranged to control said continuously variable gearbox (CVT / IVT), and thus a working point of said internal combustion engine, based on said one or fl your first parameters P1 for regulating a concentration / fraction C Ex / X Ex of one or fl your constituents in said exhaust gas stream, at least one of said one or första your first parameters P1 is a first concentration / fraction difference between said first concentration / fraction C1 / X1 in said exhaust gas stream and a reference concentration / fraction CRef / XRef.

The above-mentioned systems are preferably arranged in a motor vehicle, such as a bus, truck or another such motor vehicle.

With a method or system according to the present invention, an improved solution is obtained for regulation / control of a concentration / fraction of one or fl of your constituent substances in a exhaust current of a motor vehicle. For example, the invention enables regulation of the concentration / fraction of one or more of the constituent substances in such operating cases when regulating the concentration / fraction has not been possible or not sufficient with solutions according to known technology.

With a method or system for regulating the concentration / fraction of constituent substances according to the present invention it is possible that components in the exhaust system, such as particulate filters and catalysts, can work efficiently because the concentration / fraction of constituents in the exhaust system can be efficiently and precisely adapted to the components mentioned optimal working concentration fraction. The risk of components in the exhaust system being damaged p.g.a. for example overheating and poisoning are also reduced thereby.

Furthermore, the invention provides a more fuel efficient method of achieving a desired one concentration / fraction of constituents, or to maintain a current concentration / fraction of constituents in the exhaust stream compared with the prior art. Through to regulate the concentration / fraction of constituent substances by controlling the driveline by means of one or första your first parameters P1 according to the invention can measures which entail large 10 15 20 25 30 fuel consumption is avoided, such as activating an external heater or engine control priority concentration / fraction before engine efficiency.

Another advantage of the invention is that it is not necessary to equip the vehicle with additional parts / components to obtain the benefits of the invention since already existing parts / components in the vehicle can be used, which means a large cost savings.

Additional advantages and applications of the invention will become apparent from it the following detailed description.

Brief description of gurus The present invention is described with reference to the accompanying figures in which: figure 1 schematically shows a system comprising an internal combustion engine and a exhaust system; figure 2 schematically shows an example vehicle; figure 3 schematically shows a gas fl fate in an engine system; figure 4 schematically shows a control unit; and figure 5 shows a fate diagram of an embodiment of the invention.

Detailed description of the invention Fig. 2 schematically shows a motor vehicle 100, such as a truck, bus or the like motor vehicle. The vehicle 100 schematically shown in Fig. 2 comprises a front pair of wheels 111, 112 and a rear wheel pair with drive wheels 113, 114. The vehicle further comprises a drive line with a internal combustion engine 101 (eg a diesel engine), which is output via one of the internal combustion engines shaft 102 is connected to a gearbox 103, for example via a coupling device 106.

The coupling device can consist of an automatically controlled coupling and be controlled by the vehicle control system via a control unit 115, 208, which can also control the gearbox 103. One from the shaft 107 output shaft 103 drives the drive wheels 113, 114 via an end gear 108, such as e.g. a differential and drive shafts 104, 105 connected to the final gear 108.

The vehicle 100 further has an exhaust system arranged to divert an exhaust stream generated by the internal combustion engine 101 in a combustion therein. As shown in f1g. 1 can 10 15 20 25 30 the exhaust system include an after-treatment system (exhaust purification system) for treatment (purification) of exhaust emissions from the internal combustion engine 101. However, it is not necessary to the exhaust system includes such an e-treatment system, and in addition the exhaust system can include other parts / components such as turbo, muffler system, and gas fl exhaust gas recirculation (EGR) system.

The gearbox 103 is usually of the manual gearbox type; automated gearboxes, such as automatic transmission, automatic manual transmission (Automatic Manual Transmission, AMT) or Double Clutch Transmission (DCT); or Continuous Variable Transmission / In fi nitely Variable Transmission, CVT / IVT).

A manual gearbox 103 is a gearbox that has a number of discrete gear positions and is arranged to be operated by the driver for loading or unloading gears (e.g. forward gears and reverse gears).

An automated gearbox also has a number of gears, ie. includes a number of discrete gear positions. However, it differs from a manual gearbox in that it is steered / operated by a control system comprising one or more control units, also commonly referred to as ECUs (Electronic Control Unit, ECU). The control unit or ECU is arranged to control the gearbox 103, for example when shifting to select gear at a certain speed with a certain driving resistance.

Furthermore, the ECU can measure the speed and torque of the engine 101 and the condition of the gearbox.

Information from the motor or gearbox can be sent to the ECU in the form of electrical communication signals via, for example, a so-called CAN bus (Controller Area Network, CAN) set up in the motor vehicle 100.

The gearbox 103 has been schematically illustrated as a unit. However, it should be noted that the gearbox physically can also consist of fl your cooperating gearboxes, for example of a so-called range- gearbox, a main gearbox and a split gearbox, which are arranged along the vehicle driveline. Gearboxes as above may include any suitable number of discrete gear positions. In today's gearboxes for heavy motor vehicles, there are twelve forward gears, two reverse gears and a neutral gear position commonly occurring. 10 15 20 25 30 A continuously variable gearbox, also called a CVT gearbox or IVT gearbox, is a other type of well-known gearbox which differs from previous gearbox types by it does not have a number of discrete gear positions corresponding to different gears but instead has a continuously variable gear ratio. In this type of gearbox, the gear ratio within certain limits are set to the exact gear ratio desired.

Regarding upshift and downshift, an upshift means that a higher possible gear position in the gearbox is selected while a downshift means a lower possible gear position in the gearbox is selected. This applies to gearboxes with a number of discrete gear positions. For continuously variable gearboxes, “fictitious” gear stages can be defined and the gear shift can take place in the same way as before gearbox with discrete gear steps. However, the usual way to control one is continuous variable gearbox to allow the gear ratio to vary depending on other parameters as described in more detail in the following description. The steering of such a gearbox is usually integrated with the control of the combustion engine speed and torque, ie. its working point. A common method is to let the control of the continuously variable gearbox be based on a current drive power requirement, e.g. calculated on the basis of an accelerator pedal position and a speed of the vehicle, and which operating point provides the best efficiency for achieve said driving power requirements. The gear ratio of the continuously variable gearbox becomes thus a result of which engine speed leads to the optimal working point for current power requirements. Often aspects other than the efficiency are also considered in the choice of operating point of the engine. These can e.g. be driveability-related aspects, such as moment response times, i.e. how long it would take to reach a higher drive wheel torque, alternatively how much higher torque can be obtained over a certain period of time.

Furthermore, a so-called activation of freewheeling to the vehicle engine 101 mechanically completely disengaged from the vehicle's drive wheels 110, 111, i.e. that the driveline is opened, while deactivating freewheeling means that the driveline is closed. Releasing the drive wheels from the engine is possible examples are provided by placing the gearbox 103 in a neutral position, or by open coupling device 106. In other words, substantially no force is transmitted through the gearbox from the engine to the drive wheels at the freewheel. In the present invention, it is assumed that the driveline of the motor vehicle 100 comprises a continuous one variable gearbox (CVT / IVT) of the type described above. Furthermore, it is assumed that the motor vehicle 10 15 20 25 30 10 comprises an internal combustion engine 101 and an exhaust system coupled to the internal combustion engine for dissipation of an exhaust gas stream from an internal combustion engine.

A method according to the present invention for controlling a concentration / fraction of a or fl your constituents in the exhaust stream include the step: controlling a continuous variable gearbox (CVT / IVT), and thus an operating point of an internal combustion engine, based on a or fl are the first parameters P1 for regulating a concentration / fraction CEx / XEX of one or fl are constituents in said exhaust gas stream, wherein at least one of said one or. is first parameters P1 is a first concentration / fraction difference between said first concentration / fraction C1 / X1 in said exhaust gas stream and a reference concentration / fraction C R e f / X R e f. The reference concentration / fraction C R e f / X R e f is a desired concentration / fraction in the exhaust stream.

The one or for first parameters P1 are preferably used as input parameters to one control algorithm arranged to control the concentration / fraction in the exhaust stream to the desired value by controlling the driveline (eg gearbox and clutch). The control algorithm can be of many different types and can be an algorithm that only looks at the first parameter and uses one or fl your threshold values (eg a higher and a lower threshold value) to determine which control measure is to be taken. A more advanced control algorithm also takes others into account variables which will appear in the following description.

Using one or första your first parameters P1 for controlling one concentration / fraction of one or more of the constituents of an exhaust gas stream by controlling the driveline is given the possibility to keep the concentration / fraction in, in or out of e.g. one catalyst at the desired level and thus ensure that certain emission levels from the vehicle less than statutory limit values. This is also a fuel efficient way to steer the concentration / fraction of substances compared to other measures such as deterioration the combustion efficiency of the engine.

As for the exhaust stream, it is the gas stream that leaves an internal combustion engine and is led out via the various components of the exhaust system to the surrounding atmosphere. The exhaust flow can to some extent part is recycled (so-called EGR), expanded over a turbine to generate mechanical energy 10 15 20 25 30 ll (eg to a turbocharger or to the front of the vehicle fl), is expanded over one exhaust brake damper (to increase engine losses and brake the vehicle or to generate warmer exhaust gases to optimize exhaust gas treatment), cooled over a WHR plant and / or purified in a more or less advanced exhaust gas treatment plant.

The components of the exhaust system in Which concentration / fraction and the temperature in / on the exhaust flow (or bulk fl the fate of the exhaust stream) may need to be regulated is according to a Embodiment of the invention: the high pressure part of the exhaust and EGR system (upstream the turboturbine), and tubular elements in the low pressure part before and after restrictions, such as exhaust brake, catalytic converter or catalytic converter bypass and your urea and HC dosing systems. Also concentration / fraction in the gas in catalysts (eg DOC, ASC and SCR), traps (eg

N0x trap) and filters, both bulk and those located in the interface with the component surface, may need to be regulated.

Furthermore, according to an embodiment of the invention, said first concentration / fraction C1 / X1 and / or said second concentration / fraction C2 / X2 a concentration / fraction of a or fl your substances in the group including: oxygen 02, carbon dioxide CO 2, carbon monoxide CO, sulfur oxides SOx, nitrogen oxides NOx, nitrogen oxide NO, nitrogen dioxide NO2, nitrous oxide N2O, ammonia NH3; and particles such as soot, HC droplets and ash.

Preferred concentrations / fractions in the exhaust pipe after a final exhaust treatment step (step) immediately after before the exhaust gases leave the exhaust pipe, ie. the step after which the exhaust emissions must meet the legal requirements) are those with minimal weighted fuel and urea consumption meets statutory emission requirements. Preferred values for NO 2 / NOX ratio in to SCR the catalyst is around 50%, for example between 40-60% for the best degree of conversion of NOX must be obtained. However, the preferred NO 2 content upstream of the particulate filter (DPF) is strong depending on the temperature and the NOX / PM ratio. Furthermore, some components are in the exhaust system is sensitive to certain substances in certain phases. For example. NOX sensors are sensitive to water in liquid form. If the sensors come into contact with liquid water, they are at risk to be damaged, so the preferred concentration of liquid water droplets in this case is zero.

To reach this preferred concentration of liquid water droplets, it is maximized preferred concentration margin, i.e. the difference between the concentration gaseous water in the exhaust gases and the concentration of evaporated water at the liquid surface, for an integrated time. 10 15 20 25 30 12 Other ways of controlling the concentration / fraction with a method according to the present the invention is, for example, to reduce the oxygen concentration in the exhaust system so that local or global overtemperature is prevented in components such as particulate filters, diesel oxidation catalyst, SCR dosing unit and SCR catalyst.

According to an embodiment of the invention, furthermore, they are one or första your first parameters P1 selected from the group comprising: 0 a first concentration / fraction Cl / X1 which may be a concentration / fraction in one area of the exhaust stream or a concentration / fraction in the exhaust stream on / closest to a surface or substrate of any part or component of the exhaust system such as a particulate filter, catalyst, muffler, sensor, etc., and difference in concentration / fi reaction between the first 0 a second current the concentration / fraction C1 / X1 and a concentration / fraction CZ / XZ in the exhaust system. The second concentration / fraction CZ / XZ is different concentration / fraction in the exhaust stream than the first concentration / fraction Cl / Xl. However, the second concentration / fraction CZ / XZ can also be one concentration / fraction in an area of the exhaust stream; According to another embodiment of the invention, one or fl era of the first parameter P1 is one time derivatives and / or a time integral of the first concentration / fraction C1 / X1, or the the first concentration / fraction difference, or the second concentration / fraction difference.

The use of the time derivative is advantageous if the control system is to react quickly to one concentration / fraction change while the use of the time integral instead means that the control system takes into account long-term trends in the concentration / traction change which is advantageous for long-term control of the concentration / fraction in the exhaust system The above-mentioned current concentrations / actions and concentrations / the fractional differences and their functions can be based on sensor values obtained from one or fl your sensors arranged at, in connection with, or in the exhaust system. Signals from sensors can be sent over, for example, a communication bus or a wireless link to one or fl your control units for signal processing. Furthermore, the concentrations / fractions and the concentration / fraction differences and their functions are based on so-called virtual 10 15 20 25 30 13 sensors, ie, (current) sensor values calculated from other real sensor signals with the use of one or more of your sensor models.

The advantage of using current concentrations / fractions and concentration / fractional differences and their functions are that these can be used directly to determine the first parameter P1 without complex or resource-intensive calculations using various simulation models. Below that, even these current values can be obtained quickly.

According to another embodiment of the invention, any of them is one or the first the parameters P1 calculated (predicted) values selected from the group comprising: a calculated first concentration / fraction Cl / X1 which may be one concentration / fraction in an area of the exhaust stream or a concentration / fraction in the exhaust stream on / closest to a surface or substrate of any part or component of the exhaust system such as a particulate filter, catalyst, muffler, sensor, etc .; first a first calculated concentration / fraction difference between it the concentration / fraction C1 / X1 and a second reference concentration / fraction the exhaust gas flow. The second reference concentration / action CRefZ / XRefZ i C Refz / X Re fz is a desired concentration / fraction of e.g. a component, such as a particulate filter or catalyst, in the exhaust system for which it should have as good a function as possible or so as not to damage it; a second calculated concentration / fraction difference between the first the concentration / fraction C1 / X1 and a concentration / fraction CZ / XZ in the exhaust gas flow. The second concentration / fraction CZ / XZ is different concentration / fraction in the exhaust system is the first concentration / fraction C1 / X1.

However, the second concentration / fraction CZ / XZ can also be one concentration / fraction in an area of the exhaust stream or a concentration / fraction in the exhaust stream on / closest to a surface or substrate of any part or component of the exhaust system such as a particulate filter, catalyst, muffler, sensor, etc .; a third calculated concentration / fraction difference between the second predicted the concentration / fraction difference and a reference concentration / fraction C Re f / X Re f in the exhaust system; and 10 15 20 25 30 14 0 a time derivative and / or a time integral of the calculated first the concentration / fraction C1 / X1, or the first calculated concentration / fractional difference, or the other calculated concentration / fractional difference, or the third calculated concentration / fraction difference. The use of the time derivative is advantageous if the control system is to react quickly to one concentration / fraction change while using the time integral instead means that the control system takes into account long-term trends in beneficial in the long run / fraction change which is control of the concentration / fraction in the exhaust stream.

By using one or more first calculated parameters P1, information is obtained about how the relevant parameters will vary over time which means that systems for regulation of the concentration / fraction of constituents in the exhaust gas stream can be controlled so that desired concentration / fraction can be achieved in the best possible way in the future. This is especially true for sluggish systems whose change of concentration / fraction takes a long time to change, e.g. storage in catalysts or other components, which require early avoidance measures of overshoots in the regulation of concentration / fraction.

By calculated parameters is meant that they are pre-calculated or simulated based on (mathematical) models of the vehicle and / or the components included in the vehicle. Based on one or more calculated first parameters P1, a control strategy can be used to control it continuously variable gearbox is selected from a number of different possible control strategies. Through to calculate / simulate how the one or fl your first parameter P1 will vary over front road sections for the vehicle according to one or fl your different steering strategies can it control strategy is chosen that meets certain requirements, e.g. that the concentration / fraction of a certain substance stays within a predefined limit value and at the same time is optimal from another aspect, such as, for example, fuel and / or urea consumption. It is therefore understood from the above that the one or fl your first parameters P1 can also be calculated based on one or fl your different future control strategies for the gearbox. This embodiment thus refers to a feedback procedure where one or fl era first parameters P1 are used to calculate one or fl era control strategies based on one or fl your possible work points, ie. work points that are possible to use with regard to other requirements such as e.g. driveability or fuel consumption. 10 15 20 25 30 15 The aforementioned one or styr your control strategies are then used to calculate the new one or första your first parameters P1 or to update the existing parameters. Furthermore, it should be noted that even if only one control strategy is calculated, information can be derived from this single control strategy used by the control system to determine if it makes sense to use or if it is better to let the vehicle be driven with a current working point for steering the gearbox.

The inventors have also realized that the one or two calculated first parameters P1 can calculated over a road section in front of the vehicle, for example by simulation above the road section in front. According to this embodiment, the calculated first parameters P1 are determined based on one or fl your vehicle-specific and / or road-specific data for the vehicle. These may preferably be selected from the group consisting of: slope in front of the vehicle; curve radii for front sections of road, speed limits for front road sections; motor vehicle weight; rolling resistance of the motor vehicle; air resistance for the motor vehicle; motor-specific data such as maximum power, mine power, maximum torque, minimum torque, exhaust gas fl fate, exhaust gas recirculation content and lambda values (ie air / fuel mixture); and installation-specific data such as possible accumulation of substances and / or release of substances and / or conversion of substances in the exhaust system and a surface in the exhaust system in contact with the exhaust gas flow. Furthermore, driver interactive data related to the driver's driving style can be used when calculating the one or fl your first parameters P1 so that the future behavior of the vehicle taken into account in the calculation. Examples of driver interactive data are: use of turn signals, accelerator pedal position, and use of brakes.

An advantage of the use of vehicle-specific and / or road-specific data in the steering is that the system can determine in advance whether any control strategy for one or funktioner your functions (e.g. gear ratio, extreme load, extreme heater, fate control, etc.) need to be used to the concentration / fraction shall not fall outside a Treaty range. This is avoided use of unnecessary control strategies and furthermore the system can act proactively in case anyone action would be necessary to take, ie. the system can act in advance.

According to a particular embodiment, the first concentration / fraction C1 / X1 is one concentration / fraction in the gas stream or alternatively a concentration / fraction over a liquid or one particle in the exhaust stream and the other concentration / fraction CZ / XZ en 10 15 20 25 30 16 concentration / fraction in the exhaust stream on / closest to a surface or substrate of in the exhaust system.

The surface concentration / fraction is a concentration / fraction in the gas on / closest to a surface of the exhaust system or part of it, which affects the transport of substances to and from the surface and the chemical reactions on the surface. The concentration / fraction over a liquid refers to the concentration on a surface in the exhaust system. This concentration / fraction over a liquid will affect the transport of the amount of substance to or from the liquid, e.g. condensation or evaporation. The liquid can in this case e.g. consist of urea, water or fuel.

The concentration / fraction immediately over a particle in the gas, on the other hand, will determine the reaction rate such as growth, decomposition or oxidation of the particle which in this case e.g. may be a soot particle or a urea particle in the exhaust system In another embodiment, the first concentration / fraction C1 / X1 is one concentration / fraction in the exhaust stream upstream of an area in the exhaust system at which a concentration / fraction is desired to be obtained. This is especially advantageous when the conversion rate of a component included in the exhaust system (eg particulate filter or catalyst) is unambiguous why the output concentration / fraction will be determined by the input concentration and / or fraction into the component. This is e.g. the case at equilibrium controlled conversion of NO to NO2 in diesel oxidation catalyst (DOC) or conversion of NOX into an SCR catalyst at high temperatures. It is also special advantageous if a particulate filter (DPF) is overheating and the overheating process can stopped by removing oxygen into the particulate filter.

Furthermore, it should be understood that the one or first parameters P1 used in the control of the gearbox can consist of only current values, or consist of only calculated values, or be a combination of current and calculated values depending on the application.

According to another preferred embodiment, the control of the gearbox can take place by a The working point of the internal combustion engine is calculated based on one or two of the first parameters P1. Then the calculated operating point is used to control a gear ratio of the gearbox thereby regulating the concentration / fraction in the exhaust stream. In general, a desired / optimal working point is selected from a number of possible working points and then controlled driveline, e.g. by controlling the gearbox in this case, so that the engine reaches or comes close the optimal working point. By desired / optimal working point is meant a working point that is the best of all possible work points for the purpose the system wants to achieve. In this case, it is 10 15 20 25 30 17 best working point the working point that allows the concentration / fraction in the exhaust stream comes as close to its corresponding reference value as possible. In other cases, it may e.g. refer to one working point that leads to the lowest consumption of e.g. fuel or urea with regard to statutory emission requirements and driveability, etc.

Usually a gearbox is controlled with a working point in order to achieve the best overall efficiency driveline, but also driveability aspects are usually considered. For example, the engine speed can be set higher than optimal for a torque reserve to be available if the driver e.g. gases on before an uphill slope. According to the above embodiment, the concentration / fraction is used in the exhaust system as a parameter in the calculation of an operating point of the engine and thus Emission targets are also taken into account in the choice of working point for the engine. Thus, emission targets can achieved without the need for more fuel-intensive measures. It is not alternative necessary to equip the vehicle with additional parts / components to, for example maintain a certain conversion rate in or certain emissions in the flow out of catalyst.

The following principles for controlling the continuously variable gearbox are applicable to the engine must reach a desired calculated operating point: if the gear ratio is increased, the engine speed is increased and thus the engine load is reduced, which leads to a total concentration of CTOÉ in the exhaust stream increased and that exhaust fl fate increases; on the other hand, if the gear ratio is reduced, the engine speed and thus increasing the engine load and exhaust fl fate decreases leading to total concentration C Tot i the exhaust flow is reduced. Not all concentrations / fractions of different substances behave the same way for a load increase or a load reduction. With knowledge of the basics combustion relationship, emission chemistry, exhaust gas treatment system, and engine control strategy with with regard to e.g. air / fuel ratio, boost pressure, EGR content, injection time (s), and dosing of substances in the exhaust system, those skilled in the art realize how the engine load and engine speed should be varied to achieve a change in a given concentration or fraction. As for the change in the concentration / fraction of catalysts in the exhaust system then deteriorates their efficiency in general with increasing fl fate and decreasing temperature. At a given drive power requirements will thus generally decrease with increasing engine speed. There are exceptions, however, and therefore virtual sensors are used in practice here as well to decide in which direction the engine speed should be changed. In practice, this is realized with the use of one or more virtual sensors arranged to calculate a quantity such as one 10 15 20 25 30 18 concentration or fraction of substances. Using sensor value from said sensors the engine load and engine speed can be controlled for control of concentration / fraction.

The calculation of the working point can further be based on additional parameters. Such a additional parameter is related to a requested drive power demand value, which usually is used for the vehicle to be drivable, ie. have properties so that it can be performed on one conveniently and in a way where the vehicle as far as possible performs what the driver wants, e.g. maintains a certain speed, delivers the torque requested by the driver with the accelerator pedal, etc. This requested drive power demand value can also be taken into account with an offset value Voffset, which means that the offset value is added to or subtracted from the drive power requirement value at the calculation of the working point. With this embodiment, the freedom of choosing increases working point and thus also increases the possibilities of reaching a desired concentration / fraction in the exhaust system because the steering system allows the steering to deviate from the vehicle's current drive power requirements, ie. the steering system can deliberately allow the vehicle to accelerate or decelerate in favor of a desired concentration / fraction in the exhaust system. Because, however, there is a danger in letting the vehicle accelerate if the offset value is added to the drive power requirement value, it is preferably about the offset value Voffset is subtracted from the drive power requirement value, which means that the vehicle is decelerated or at least not accelerated because if a driver requests a driving effect which corresponds to an acceleration, a reduction in the driving power with the Voffset can lead to a reduced acceleration and not necessarily to a deceleration of the vehicle.

Other additional parameters that can be used in the calculation of the working point are parameters related to: 0 an efficiency for the driveline which must be weighed in to get such a fuel efficient driving the vehicle as possible, 0 an efficiency for an exhaust gas treatment system (also called after-treatment system) set up in the exhaust system to obtain such a high conversion rate in catalysts and thus as low emissions as possible, 0 exhaust emissions for the internal combustion engine before being purified by one exhaust gas treatment system, 0 speed limits of the engine and driveline so as not to end up higher or lower in engine speed than the driveline is dimensioned for, 10 15 20 25 30 19 0 engine torque / power curve as a function of speed to determine how a lot of elements that are available, 0 and torque response, i.e. how quickly a requested increased drive wheel torque has an impact the actual drive wheel torque of the vehicle. This aspect is relevant in the calculation of the working point as the driver's control of the accelerator pedal must also be taken into account. Otherwise there is a risk that the driver experiences it as if the vehicle does not respond to his control of the accelerator pedal; and 0 other drivability aspects such as sound, vibration and vibration of the vehicle so that the vehicle can be driven in a comfortable way. Parameters related to extreme loads are also very useful in the calculation and the control of the working point. An example of an extreme load is a system arranged for conversion of exhaust gas shielding for energy (WHR); auxiliary units such as water pump, fl shaft or compressor; generator; hybrid generator or equivalent energy recovery system; retarder, exhaust brake or other additional brother. The power requirement of the external load can be controllable for the freedom increases when selecting a working point for the motom, which in turn means that even working points such as is outside the vehicle's propulsion requirements can be used to regulate the concentration in the exhaust system. In some cases, the extreme load is of the type "on" or "off", ie. that it either is activated or not activated, and in these cases the control and calculation are limited by the working point to determine whether the extreme load should be activated or not.

Furthermore, if no exhaust brake is installed in the exhaust system or if the exhaust brake is arranged to regulate the exhaust flow downstream thereof, the extreme load applies shall be increased if a total concentration C ExTÛt in exhaust systems is to be reduced; and if the total concentration C ExTOt shall be increased and the extreme load shall be reduced. However, if one exhaust brake is set up in the exhaust system and is arranged to regulate an exhaust flow upstream the same applies instead that the extreme load must be increased if the total concentration CExTot in one area upstream of the exhaust brake shall be increased in the event that a quotient for the pressure exceeds the temperature will increase. On the contrary, the extreme load should be reduced if the total concentration C ExTot i the area shall be reduced in the event that the ratio of the pressure above the temperature will decrease.

The dependence of the total concentration on the extreme load is given by the general gas law. With increased load 10 15 20 25 30 20 increases the temperature of the exhaust gases normally and thereafter the total concentration falls given that the pressure is kept constant.

It has further been realized by the inventors that the one or more first parameters P1 are suitable to be used for the control of other functions of the vehicle for the control of the concentration / fraction. These functions must have a direct or indirect effect on the concentration / fraction. Thus, the concentration / fraction can be regulated more efficient and faster. Appropriate fi actions are related to extreme warming of the exhaust system; injection of fuel into the engine; injection of fuel, urea or other suitable liquid for the exhaust system; and regulation of exhaust fate. It should be understood that they are one or första your first parameters P1 can be used to control such an eller function or combination of two or fl your such fi actions.

According to one embodiment, the one or första first parameters P1 can be used to control at least one extreme heater for the exhaust system. The external heater has the task of increase or decrease the concentration / fraction of constituents of the exhaust gas or in the exhaust gas any part / component in the exhaust system. Preferably, the external heater is one of: A burner arranged in the exhaust system after the cylinders of the internal combustion engine; A system arranged for post-injection of hydrocarbons for oxidation or combustion on a catalyst placed in the exhaust system; 0 an electric heater arranged in the exhaust system after the cylinders of the internal combustion engine; or 0 any other suitable external heater set up in, or in close proximity to the exhaust system.

The external heater is preferably controlled so that a maximum concentration reduction is obtained in relation to input or total energy. But the external heater can instead be controlled so that the rate of change of the concentration / fraction is prioritized. The control of the external the heater can be designed as a PID or MPC controller.

As mentioned above, the one or första your first parameters P1 can also be used for control of a fuel injection system arranged to inject fuel into internal combustion engine. This can be done by controlling the number of mail injections, the time (CAD, ie crank angle degree) for the post injections and the amount of fuel per post injection. 10 15 20 25 30 21 The control of the fuel injection system can be implemented as disturbed or feedback control with e.g. MAP (matrix-based control structure), PID, or MPC (Model Predictive Control, MPC). As a setpoint for this control, a concentration / fraction can be downstream engine as well as a particulate filter (DOC) or as a concentration / fraction difference above said particle filter is used. In an execution form, the regulation compensates for the efficiency of reactions in a component included in the exhaust system, for example the efficiency of NO to NO2 conversion in a diesel oxidation catalyst. Furthermore, they can one or fl your first parameters P1 are used for control of an injection system arranged for injection of fuel, urea or other suitable liquid into the exhaust system for regulating concentration / fraction C Ex / X Ex of one or fl of the constituents in the exhaust gas stream.

Another factor that affects the concentration / fraction in the exhaust system CEx / X Ex is the characteristics of the exhaust gas fl the fate of the exhaust stream. For this reason, they can also one or for your first parameters P1 are further used to control the exhaust fl fate, or one of exhaust fl fate dependent parameters such as mass transition numbers.

Control of the exhaust gas can be done by controlling a gas exhaust system for exhaust gas recirculation (Exhaust Gas Recirculation, EGR) and / or by controlling an intake system for the engine. Fig. 3 schematically shows a general gas fate in an engine system, the engine system in this example includes a diesel engine with a turbo and a number of tubes connected to the engine.

Air is sucked in from the left in Fig. 3 by means of an intake system for the engine. The air that is sucked in passes through an intake manifold and is compressed in a turbocharger to then is cooled in a charge air cooler before passing a throttle which in some cases regulates the amount of air into the diesel engine. After the throttle, the air is mixed with recycled exhaust gases by means of a gas d exhaust system for exhaust gas recirculation (EGR) and this mixture is then sucked into the engine cylinders to be mixed with diesel before combustion takes place in the engine.

The exhaust gases from the combustion process then pass through a turbo turbine which accelerates the turbocharger. However, parts of the exhaust gases enter an EGR pipe and are led back to the intake manifold via an EGR damper and one or fl your EGR coolers. The function of the EGR damper is to regulate the amount of exhaust gases returned to the combustion process. When the EGR gases are cooled the use of EGR will fl transfer thermal energy from the exhaust gases to the engine cooling system. 10 15 20 25 30 22 Before the exhaust gases completely disappear from the engine system, they pass an exhaust damper in some engines. (if one is installed) which controls the pressure in an exhaust gas collector (not shown in the figure). Then the exhaust gases pass through a post-treatment system which may contain a diesel particulate filter and / or an SCR catalyst as previously mentioned. If the motor 101 is not heavily loaded the exhaust gases will have a lower temperature than desired and thus cool down the catalyst. One way to limit the amount of cooling exhaust gases is the use of a damper arranged in one intake pipe for air to the engine. Thus, the amount of air into the engine can be limited as in its This in turn leads to the exhaust gases from the engine also being limited, which results in a given load warmer exhaust gases with a usually higher fraction of combustion products. This damper is called usually throttle, as mentioned above. Regarding the amount of air as the engine consumer, this is largely determined by the speed of the motor, which in this case means: ju higher engine speed the higher the air luft fate required for the engine.

According to the present invention, the one or more first parameters P1 can be used to control gas fl exhaust gas recirculation (EGR) system and / or intake system regulation of an air inflow to the engine. In addition, the control of the gas fate system can exhaust gas recirculation (EGR) and the intake system are controlled with an additional parameter related to emissions produced by said internal combustion engine. Emissions are understood here for example, exhaust emissions and noise. Furthermore, a reduction in exhaust fumes can be combined with an increase in engine load to change the fraction of any component in the exhaust system. This embodiment can be realized by means of, for example, disturbed or feedback control of an exhaust brake using: a setpoint for the fraction or a value which is a function of said setpoint for the fraction.

Furthermore, Pig shows. 5 is a flow chart of an exemplary embodiment of the method according to FIG the invention: A. At A, the first parameter P1 is measured, or calculated from other sensor signals (virtual sensor). The first parameter P1 can also be calculated over the preceding road sections for the vehicle at A.

B. Based on the value of the first parameter P1, a regulatory measure for concentration / fraction of constituents in the exhaust stream needs to be taken. This can for example by comparing the first parameter P1 with a threshold value, 10 15 20 25 30 23 or by comparing fl your calculations of the first parameter P1 with related control strategies and based on these choose which regulatory action (s) are needed taken.

C. If a regulating measure is to be applied, the working point of the motor is calculated at C. which in the best way (eg fastest or most fuel efficient) leads to a desired one concentration / fraction in the exhaust stream.

D. The working point calculated at C is weighed together with other working points at D, which have calculated with respect to other aspects, such as driveability. This can for example mean that the resulting engine speed becomes an average of fl your inputs work points. At D it is also decided how the working point is to be reached, ie. how external load, engine and gearbox must be controlled.

E. At E, the external load is controlled to the desired position (desired torque).

F. At F, the gearbox and motor are controlled so that the desired operating point (speed / torque) is reached.

G. If the adjustment of the working point is not sufficient to achieve the desired concentration / fraction, it is decided at G whether an external heater is to be activated. Though the extreme heater could have been activated at B.

H. At H, the external heater is controlled according to the decision at G. 1. If the adjustment of the working point is not sufficient to reach the desired concentration / fraction in the exhaust system, it is decided at I whether the exhaust fate is needed controlled by e.g. using an EGR and / or a throttle.

J. At J, the exhaust av fate is controlled after the decision at I.

The present invention can be further implemented in a control system comprising, for example a control unit arranged to control all or part of a driveline of a motor vehicle 100. Further the system may comprise additional control units arranged to control other functions such as extreme load, extreme heater, etc. Control units of the type shown are normally arranged to take receive sensor signals from different parts of the vehicle and as well as from other control units. These control units are furthermore usually arranged to emit control signals to different vehicle parts and vehicle components. The control units can also include, or be connected to one calculation unit arranged for calculation / simulation of predicted parameter values.

Usually, control systems in modem vehicles consist of a communication bus system consisting of one or fl your communication buses for interconnecting a number of electronic control units 10 15 20 25 30 24 (ECUs) or controllers, 115, 208, and various components fitted to the vehicle. One such control systems can include a large number of control units and the responsibility for a specific function in the vehicle may be divided into one or more control units.

The control is often done with programmed instructions. These programmed instructions is typically a computer program, which when executed on a computer or controller causes the computer / controller to perform the desired control, such as methods of the present invention invention. The computer program is usually part of a computer program product, there the computer program product includes an applicable storage medium l1l with the computer program 109 stored on said storage medium 121. Said digital storage medium 121 may e.g. consists of someone from the group: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), a hard disk drive, etc., and be arranged in or in connection with the control unit, wherein the computer program is executed by the control unit.

An exemplary control unit (control unit 208) is shown schematically in Fig. 4, the control unit in turn may comprise a calculation unit 120, which may consist of e.g. any suitable type of processor or microcomputer, e.g. a digital signal processing circuit Processor, DSP), or a circuit with a predetermined specific function (Application Specific Integrated Circuit, ASIC). The computing unit 120 is further connected to a memory unit 121, which provides the calculation unit e.g. the stored program code 109 and / or the stored data calculation unit needs to be able to perform calculations.

The calculation unit is also arranged to store partial or final results of calculations in memory unit 12 1.

Furthermore, the control unit is provided with means / devices 122, 123, 124, 125 for receiving respectively transmitting input and output signals. These input and output signals can contain waveforms, pulses, or other attributes, which of the input signal receiving devices can be detected as information for processing the computing unit 120. The devices 123, 124 for transmitting output signals are arranged to convert calculation results from the calculation unit 120 to output signals for transmission to other parts of the vehicle control system and / or the component (s) for which the signals are intended. Each of the connections to the devices for receiving and transmitting input and output signals, respectively, can be constituted 10 15 25 of one or fl era of a cable; a data bus, such as a CAN, a MOST (Media Oriented Systems) Transport), or any other suitable bus configuration or wireless communication connection.

More specifically, a system according to the present invention comprises a control unit arranged to control a continuously variable gearbox (CVT / IVT), and thus a working point of a internal combustion engine, based on one or fl your first parameters P1 for regulating a concentration / fraction C Ex / X Ex of one or fl your constituents in an exhaust gas stream, whereby at least one of said one or första your first parameters P1 is a first concentration / fraction difference between said first concentration / fraction C1 / X1 in said exhaust gas stream and a reference concentration / fraction CRef / XRef. Furthermore, the present invention relates to further comprising a motor vehicle 100, such as a bus, truck or similar motor vehicle at least one system as above.

Finally, it should be understood that the present invention is not limited to those described above embodiments of the invention without referring to and including all embodiments within them attached sj independent scope of protection requirements.

Claims (27)

10 15 20 25 30 26 PATENT REQUIREMENTS A method of controlling a concentration / fraction of one or more constituents of an exhaust stream in a motor vehicle by controlling its driveline, which motor vehicle comprises: a driveline comprising an internal combustion engine connectable to a continuously variable gearbox (CVT / IVT) via a coupling device, and an exhaust system arranged to divert an exhaust stream from said internal combustion engine; said method comprising the step of: - controlling said continuously variable gearbox (CVT / IVT), and thus a point of action of said internal combustion engine, based on said one or more first parameters P1 for controlling a concentration / fraction C Ex / X Ex of a or fl your constituents in said exhaust gas stream, wherein at least one of said one or fl your first parameters P1 is a first concentration / fraction difference between said first concentration / fraction C1 / X1 in said exhaust gas stream and a reference concentration / fraction C Re f / X Re f. A method according to claim 1, wherein at least one of said one or fl your first parameters P1 is a first concentration / fraction Cl / X1 and / or a second concentration / fraction difference between said first concentration / fraction Cl / X1 and a second concentration / fraction CZ / X 2 in said exhaust gas stream. The method of claim 2, wherein said first concentration / fraction C1 / X1 is a concentration / fraction in said exhaust stream upstream of an area in said exhaust stream at which a concentration / fraction is desired to be obtained. A method according to any one of the preceding claims, wherein at least one of said one or fl first parameters P1 is a time derivative and / or a time integral of said first concentration / fraction C1 / X1 and / or said first concentration / fraction difference and / or said other concentration / fraction difference. A method according to any one of the preceding claims, wherein at least one of said one or första your first parameters P1 is calculated over said motor vehicle front section 10 15 20 25 30 27 based on one or fl your vehicle-specific and / or road-specific data for said motor vehicle. The method of claim 5, wherein said vehicle-specific and / or road-specific data is selected from the group consisting of: a road slope; curve radii, velocity limits; a weight for said motor vehicle; a rolling resistor; an air resistance; engine specific data such as maximum power, mine power, maximum torque, minimum torque, exhaust fate, exhaust gas recirculation content, lambda values, and injection parameters. A method according to any one of claims 2-6, wherein said first concentration / fraction C1 / X1 is a concentration / fraction of a gaseous substance or a concentration of solid particles or liquid droplets, and said second concentration / fraction CZ / XZ is a concentration / fraction in said exhaust stream on / near a surface or substrate of said exhaust system. A method according to any one of claims 2-7, wherein said first concentration / fraction Cl / X1 and / or said second concentration / fraction CZ / XZ is a concentration / fraction of one or more substances in the group comprising: oxygen O 2, carbon dioxide CO 2 , carbon monoxide CO, sulfur oxides SOx, nitrogen oxides NOx, nitrogen oxide NO, nitrogen dioxide NO2, nitrous oxide N20, ammonia NHS; and particles such as soot, HC droplets and ash. A method according to any one of the preceding claims, wherein the control comprises: - calculating at least one operating point of said internal combustion engine based on said one or fl your first parameters P1; and - controlling a gear ratio of said continuously variable gearbox (CVT / IVT) based on said operating point. The method of claim 9, wherein the calculation of said operating point is further based on an additional parameter related to a requested drive power demand value or to a requested drive power demand value taking into account an offset value Voffset. 10 15 20 25 30 28 The method of claim 10, wherein said offset value Voffset is subtracted from said requested drive power demand value. A method according to any one of claims 9-11, wherein the calculation of said operating point is further based on one or more additional parameters related to at least one selected from the group comprising: an efficiency of said driveline, an efficiency of an exhaust gas treatment system arranged in said exhaust system, exhaust emissions for said internal combustion engine, a torque response, and driveability aspects. A method according to any one of claims 9-12, wherein the calculation of said operating point is further based on one or more additional parameters related to at least one external load selected from the group comprising: a system arranged for converting the exhaust shield to energy (WHR); auxiliary units such as water pump, fl shaft or compressor; generator; hybrid generator or equivalent energy recovery system; retarder, exhaust brake or other auxiliary brake. A method according to claim 13, wherein if no exhaust brake is provided in said exhaust system or an exhaust brake is arranged to regulate an exhaust flow downstream thereof, said external load: - increased if a total concentration C EXTOÉ in said exhaust system is to be reduced, and - reduced if total concentration C ExTot in said exhaust system shall be increased. A method according to claim 13, wherein if an exhaust brake is set up in said exhaust system and is arranged to regulate an exhaust flow upstream thereof, said external load: - increased if a total concentration C ExTot in an area upstream of said exhaust brake is to be increased, and - decreased if said total concentration C ExTÛt in said area upstream of said exhaust brake shall be reduced. A method according to any one of claims 9-15, wherein the control of said continuously variable gearbox (CVT / IVT) comprises: - increasing or decreasing said gear ratio for controlling said concentration C Ex in said exhaust system based on sensor values obtained from one or fl era sensors 10 15 20 25 30 29 arranged for detecting or calculating the concentration / fraction of one or more of the constituent substances in said exhaust system. A method according to any one of the preceding claims, wherein the method further comprises: - controlling an exhaust gas fate of said exhaust gas stream, or a parameter dependent on said exhaust gas fate such as mass transition number, based on said one or two first parameters P1 for controlling said concentration / fraction C Ex / X Ex of one or fl your constituent substances in the said exhaust system. A method according to any one of the preceding claims, wherein the method further comprises: - controlling at least one external heater based on said one or första your first parameters P1 for lowering or raising said concentration / fraction C Ex / X Extemperature in said exhaust system. The method of claim 18, wherein said external heater is any selected from the group consisting of: a burner arranged in said exhaust system after the cylinders of said internal combustion engine; a system arranged for injecting hydrocarbons for oxidation or combustion on a catalyst placed in said exhaust system; an electric heater arranged in said exhaust system or the cylinders of said internal combustion engine; and another external heater set up in or in close proximity to said exhaust system. A method according to any one of the preceding claims, wherein the method further comprises: - controlling a fuel injection system arranged for injecting fuel into said internal combustion engine based on said one or fl your first parameters P1 for controlling said concentration / fraction C Ex / X Ex of a or fl your constituents in the said exhaust system. A method according to any one of the preceding claims, wherein the method further comprises: - controlling an injection system arranged for injecting fuel, urea or other liquid into said exhaust system based on said one or första your first parameters P1 for controlling said concentration / fraction CEx / XEX of one or more of the constituents of the said exhaust system. 10 15 20 25 30 30 A method according to any one of the preceding claims, wherein the method further comprises: - controlling a gas fl exhaust system for exhaust gas recirculation (EGR) arranged for said internal combustion engine based on said one or fl your first parameters P1 for controlling said concentration / fraction CEx / XEX of one or fl your constituents in the said exhaust system; and / or - controlling an intake system arranged for controlling a lu fi inlet to said internal combustion engine based on said one or första your first parameters P1 for controlling said concentration / fraction C Ex / X Ex of one or more constituents in said exhaust system. The method of claim 22, wherein the control of said exhaust gas recirculation (EGR) fate system and / or the control of said intake system is further based on an additional parameter related to emissions produced by said internal combustion engine. A computer program comprising program code, which when said program code is executed in a computer causes said computer to perform the method according to any one of the preceding claims. A computer program product comprising a computer readable medium and a computer program according to claim 24, wherein said computer program is included in said computer readable medium. A system arranged to control one or more of the functions of a motor vehicle, the motor vehicle comprising: a driveline comprising an internal combustion engine connectable to a continuously variable gearbox (CVT / IVT) via a coupling device, and an exhaust system arranged to divert an exhaust stream from said internal combustion engine; said system being characterized by comprising a control unit arranged to control said continuously variable gearbox (CVT / IVT), and thus a working point of said internal combustion engine, based on said one or fl your first parameters P1 for controlling a concentration / fraction C Ex / X Ex of one or fl your constituents in said exhaust gas stream, wherein at least one of said one or fl your first parameters P1 is a first concentration / fraction difference between said first concentration / fraction C1 / X1 in said exhaust gas stream and a reference concentration / fraction CR ef / XR ef. A motor vehicle comprising at least one system according to claim 26.