SE1450254A1 - Procedure and system for regulating an internal combustion engine - Google Patents

Abstract

The present invention relates to a method of controlling an internal combustion engine (101), said internal combustion engine (101) comprising at least one combustion chamber (201) and means (202) for supplying fuel to said combustion chamber (201), wherein combustion in said internal combustion chamber (201) occurs in combustion cycles. The method is: during a first combustion cycle and by using first sensor means (406), determining a first parameter value representing a quantity with respect to said combustion chamber. (201), - by using said first parameter value, determining a first amount of additives for supply to said combustion chamber, and - supplying to said combustion chamber (201) said first amount of additives. The invention also relates to a system and a vehicle. 5

Description

FIELD OF THE INVENTION The present invention relates to combustion engines, and in particular to a method of controlling an internal combustion engine according to the preamble of claim 1.

The invention also relates to a system and a vehicle, as well as a computer program and a computer program product, which implement the method according to the invention.

Background of the Invention The following description of the invention constitutes a background description of the invention, and thus does not necessarily constitute a prior art.

Due to increased government interests regarding pollution and air quality, emission standards and emission regulations regarding emissions from internal combustion engines have been developed in many jurisdictions.

Such emission regulations often constitute sets of requirements which define acceptable limits for exhaust emissions in vehicles equipped with internal combustion engines. For example, levels of emissions of nitrogen oxides (NO), hydrocarbons (HC) and carbon monoxide (CO) are often regulated. These emission regulations can also e.g. manage the presence of particles in exhaust emissions.

In a penalty to comply with these emission regulations, the exhaust gases caused by the combustion engine combustion are treated (purified). For example. can a s.k. catalytic purification process is used, why oaks & exhaust gas treatment systems, as in e.g. vehicles and other vehicles, usually include one or more catalysts and / or other components. For example. exhaust gas treatment systems in vehicles with diesel engines often include particulate filters. 2 Catalysts in internal combustion engines can consist of a number of different types, where different types may be required for different industries and / or conversion of different but undesirable compounds present in the exhaust stream. Regarding at least nitrous gases (nitrogen monoxide, nitrogen dioxide), hereinafter collectively referred to as nitrogen oxides NOR, heavy vehicles often comprise a catalyst where an additive is supplied to the exhaust gas stream resulting from the combustion engine combustion to reduce nitrogen oxides NO mainly to nitrogen gas and water vapor.

This reduction in emissions of nitrogen oxides from diesel engines is usually carried out by a method called SCR (Selective Catalytic Reduction). This method involved adding an additive, usually an aqueous solution containing the substance urea, in an appropriate dose to the exhaust stream upstream of an SCR catalyst.

The function of the SCR catalyst usually requires access to ammonia (NH3), and in e.g. evaporation of urea also forms ammonia, whereby then ammonia in the SCR catalyst reacts with nitrogen oxides in the exhaust stream with conversion to nitrogen gas and water vapor as a result.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of controlling an internal combustion engine. This object is achieved by a method according to claim 1.

The present invention relates to a method for controlling an internal combustion engine, said combustion engine comprising at least one combustion chamber and means for supplying fuel to said combustion chamber, wherein combustion in said 3 combustion chambers takes place in combustion cycles. The method is characterized by: during a first combustion cycle and by using first sensor means determining a first parameter value representing a quantity with respect to said combustion chamber, by using said first parameter value, determining a first quantity of additive for supply to said combustion chamber and combustion chamber, add the said first amount of additive.

Said additives can e.g. constitute an additive for the reduction of nitrogen oxides resulting from combustion in said combustion chamber. During combustion in internal combustion engines, in particular diesel engines, unwanted nitrogen oxides NOR are generated, at least in part due to the excess oxygen that is generally applied during combustion in diesel engines. Alternatively, the additive may relate to the reduction of another substance resulting from the combustion.

As has been called required, e.g. due to regulatory regulations, often some type of exhaust gas treatment in order to reduce the amount of nitrogen oxides in the exhaust stream before the exhaust stream is released into the vehicle environment, where this reduction in emissions can be accomplished by injecting additives in an appropriate dose to the exhaust stream upstream of an SCR catalyst .

The additive is then evaporated on contact with the hot exhaust gases, whereby ammonia is formed / released to then in the SCR catalyst reduce nitrogen oxides in the exhaust gases to nitrogen gas and water vapor. The additive can be supplied by means of an injection system comprising one or more nozzles for injecting the additive into the exhaust stream. With the correct dosage of additives, emissions of nitrogen oxides can be greatly reduced.

The desired function when injecting additives is, however, dependent on the exhaust gases reaching a sufficiently high temperature for the additive to be lined. During large parts of a diesel engine's operating condition, the exhaust gases also usually reach a sufficiently high temperature for undesired displacement to occur.

However, there are situations where this cannot be guaranteed, and it may be difficult to avoid, at least in certain operating conditions, some of the injected additive, such as e.g. a urea / water solution, in a joke required condition comes into contact with cradle surfaces of e.g. one or more of exhaust pipes, catalytic converter, muffler. In such situations, urea / urea-based compositions can adhere to cradle surfaces in the exhaust system.

If the formation of solid formations is greater than the formation of the formed coating, a successive coating build-up will take place. The result of unfavorable conditions can be a significant build-up of solid material. These structures can grow large enough that the performance of the internal combustion engine is affected by the exhaust flow in the exhaust system being affected (throttled), and with a large coating build-up, continued engine operation can in any case be completely prevented. The coating can also damage components in the finishing system if formed formations, e.g. in the form of lumps, the frin relaxes the place where they have formed and then rushes with the exhaust stream to e.g. a subsequent SCR catalyst or other components. Coating formation can also lead to a reduction in the exhaust gas cleaning function.

According to the present invention, such problems with coating formation can be reduced. Likewise, the need for SCR catalysts can be reduced or completely eliminated. In addition, the use of additives can be adapted to prevailing needs, whereby excessive supply of additives, with associated costs, can be reduced.

According to the invention, additives are injected directly into the combustion chamber of the internal combustion engine. The temperature in the combustion chamber Or, At least in the combustion of fuel, significantly higher On in e.g. The SCR catalyst, i.e. the exhaust stream, is gradually cooled down as the exhaust pipe is passed, e.g. due to the fact that the exhaust pipe is usually cooled by ambient air. It is also, among other things. Due to this cooling that the SCR catalyst is required, otherwise the reaction rate when reducing NO by using the additive would be too low for the desired reduction to have time to be carried out before the exhaust stream is discharged into the vehicle's surroundings.

In the combustion chamber of the combustion engine, on the other hand, the temperature is usually so high that the desired reaction rates can be achieved without the aid of a catalyst, and by injecting additives directly into the combustion chamber a very high reaction rate can be obtained while reducing the resulting nitrogen oxides. hog.

According to a preferred embodiment of the present invention, the nitrogen oxides resulting from the combustion are estimated, whereby an appropriate amount of additive can be injected as a function of the estimated amount of nitrogen oxides resulting from the combustion. The estimation can e.g. is carried out during a combustion cycle, 6 whereby the amount of injection injected during subsequent combustion cycles can be regulated based on the said estimated amount of nitrogen oxides.

When determining the applicable amount of additive for injection, e.g. the known chemical relationships in the reaction between additives and nitrogen oxides are applied to determine the applicable amount of additives for supply to the combustion chamber. In this determination, the temperature of the combustion chamber can also be estimated, whereby the amount of additive e.g. can hero of advanced reaction rate.

According to one embodiment, a part of the required additive may be arranged to be injected into the combustion chamber, while a further part may be injected in a conventional manner downstream of the combustion engine, whereby part of the reduction can be carried out in the combustion chamber and a part in e.g. and SCR catalyst.

According to one embodiment, an external injector arranged in the exhaust pipe is not required for the supply of additives, but instead additives are supplied via the combustion engine's combustion chamber for transport to e.g. a catalyst such as an SCR catalyst. Additives fed to the combustion chamber according to this embodiment can thus be used partly for reduction in the combustion chamber and partly for reduction in a subsequent catalyst, or alternatively entirely for use in a subsequent catalyst.

Furthermore, estimating the amount of combustion resulting nitrogen oxides can e.g. be arranged to be carried out at appropriate times, as every time a significant change of the combustion takes place, as e.g. a change in the amount of fuel injected. For example. estimation can be performed during one or an applicable number of combustion cycles, whereby then injection of additives can be performed based on said estimation, 7 e.g. as long as the conditions are the same or essentially the same.

According to one embodiment, the amount of resulting nitrogen oxides for the usual combustion cycle and during the current combustion cycle is estimated, whereby the supply of additives for the regular combustion cycle can be adapted during the current combustion cycle to the combustion of the current combustion cycle, and Oven is injected during the continuous combustion cycle.

According to one embodiment, the above signals are applied from a NOx sensor arranged downstream of the combustion engine when determining the applicable amount of additive for supply to the combustion chamber. In this case, e.g. an undesired high NOR content indicated by the NOx sensor causes an increase in the amount of reducing agent added.

According to one embodiment, the above radiating temperature in the combustion chamber is estimated / used, whereby injection of additives e.g. may be arranged to be carried out only if the temperature of the combustion chamber exceeds any applicable temperature. This has the advantage that unwanted coating formations in / downstream of the combustion chamber and caused by additives to a large extent can be avoided.

According to an embodiment of the invention, an additional fuel injection is carried out before or at the same time as the injection of additives, whereby the temperature in the combustion chamber can be raised by utilizing the additional fuel injection, thereby enabling desired chemical reactions.

According to one embodiment of the invention, the invention is combined with a control of the combustion engine combustion during the current combustion cycle, where the combustion can be controlled against a number of criteria, such as one or more of: resulting 8 nitrogen oxides, combustion temperature, pressure amplitude and / or pressure change rate, work at the burning.

The injection of additives can also be arranged to be performed individually for each cylinder, ie. the resulting nitrogen oxides can be determined individually for each combustion chamber, whereby injection of additives can be adapted individually for each combustion chamber.

The invention thus enables regulation where e.g. differences between different cylinders can be detected and nitrogen oxide variations can be compensated by using individual adaptation of the injected amount of additive for each combustion chamber. It may also be the case that the injection of different amounts of additives into different combustion chambers can be harmful, e.g. to steer certain cylinders against fulfillment of any criterion, and other cylinders against any other applicable criterion, which can also be achieved according to the invention. Furthermore, only one or a subset of the cylinders can be arranged to be controlled according to the invention, while the combustion in other cylinders can be carried out in the usual or otherwise applicable manner.

The process of the present invention can e.g. implemented by utilizing one or more FPGAs (Field-Programmable Gate Array) circuits, and / or one or more ASIC (application-specific integrated circuit) circuits, or other types of circuits that can handle the desired computational speed.

Additional features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments and the accompanying drawings. Brief Description of the Drawings Fig. 1A schematically shows a vehicle in which the present invention can be used.

Fig. 1B shows a control unit in the control system of the vehicle shown in Fig. 1A.

Fig. 2 shows the finishing system in more detail for the vehicle shown in Fig. 1.

Fig. 3 shows an example of a dosing system for supply of additives to the exhaust stream.

Fig. 4 shows the internal combustion engine of the vehicle shown in Fig. 1A in more detail.

Fig. Shows an exemplary method according to the present invention.

Fig. 6 shows an example of temperature savings, nitric oxide change and heat release for a combustion.

Fig. 7 shows an example of a pressure pair in a combustion chamber where injection of additives is performed before combustion.

Detailed Description of Embodiments Fig. 1A schematically shows a driveline in a vehicle 100 according to an embodiment of the present invention. The driveline comprises an internal combustion engine 101, which in a conventional manner, via a shaft extending on the internal combustion engine 101, usually via a flywheel 102, is connected to a gearbox 103 via a clutch 106.

The combustion engine 101 is controlled by the control system of the vehicle via a control unit 115. Likewise, the clutch 106, which e.g. can be constituted by an automatically controlled clutch, and the shaft 103 of the vehicle control system by using one or more applicable control units (not shown). Of course, the vehicle's driveline can also be of another type such as e.g. of a type with conventional automatic gearbox or of a type with a manually geared gearbox etc.

A shaft 107 emanating from the gearbox 103 drives drive wheels 113, 114 in the usual manner via end shaft and drive shafts 104, 105. In Fig. 1A only one shaft with drive wheels 113, 114 is shown, but in the usual way the vehicle can comprise more than one shaft provided with drive wheels, as well as one or more additional axles, such as one or more stand axles. The vehicle 100 further comprises an exhaust system with a post-treatment system 200 for the usual treatment (purification) of exhaust emissions resulting from combustion in the combustion chamber (eg cylinders) of the combustion engine 101.

The after-treatment system is shown in more detail in Fig. 2. The figure shows the internal combustion engine 101 of the vehicle 100, which consists of an engine with a turbo, for which the exhaust gases generated during combustion are led via a turbocharger 220. Alternatively, the turbocharger can e.g. be of compound type.

The function for different types of turbochargers is valkand, and is described need not be closer.

The exhaust stream is then passed via a pipeline 204 (indicated by arrows) to a diesel particulate filter (DPF) 202 via a diesel oxidation catalyst (DOC) 205. During combustion in the internal combustion engine, soot particles are formed, and the particulate filter 202 is used for combustion. these soot particles. The exhaust stream is passed through a filter structure where soot particles are captured from the passing exhaust stream and stored in the particulate filter.

Regarding the oxidation catalyst DOC 205, this has several functions, and is normally used primarily to oxidize the remaining hydrocarbons and carbon monoxide in the exhaust stream to carbon dioxide and water during the post-treatment. The oxidation catalyst 205 can also oxidize a large proportion of the nitrogen monoxides (NO) present in the exhaust stream to nitrogen dioxide (NO2). The oxidation of nitrogen monoxide NO to nitrogen dioxide NO2 is advantageous in the reduction of nitrogen oxides NOR. As mentioned above, for this purpose a SCR (Selective Catalytic Reduction) catalyst 201 is usually used, which uses ammonia (NH3), or a composition from which ammonia can be generated / formed, such as e.g. urea, as an additive to reduce the amount of nitrogen oxides NOx the exhaust gas stream. However, the efficiency of this reduction is affected by the ratio between NO and NO2 in the exhaust gas stream, whereby the reaction of the reduction is affected in a positive direction by ferrous oxidation of NO to NO2.

Regarding the present invention, the finishing system can generally be of different types, and needs e.g. do not include particle filter 202 or oxidation catalyst 205. According to a preferred embodiment, no SCR catalyst is required, since the reduction of nitrogen oxides can be completely carried out in the combustion chamber of the internal combustion engine. The finishing system may also include additional components not shown.

The SCR catalyst therefore requires additives to reduce the concentration of nitrogen oxides in the exhaust gases. This additive is often urea-based, and can e.g. consists of the product AdBlue, which in principle consists of urea mixed with water.

An example of a conventional additive supply system is shown in more detail in Fig. 3, where of the above components only particle filter 202 and SCR catalyst 201 are shown, and where the system in addition to said catalyst 201 comprises a urea tank 302, which is connected to a urea dosing system (UDS) 303.

The urea metering system 303 includes, or is controlled by, a UDS control unit 304, which generates control signals for controlling the supply of additives so that the desired amount is injected into the exhaust stream resulting from the combustion in the cylinders of the internal combustion engine 101 from the urea tank 302 by means of an injection nozzle SCR 30. 201. Fig. 3 also shows a NOR sensor 308 arranged downstream of the SCR catalyst 201.

The more specific function of the urea dosing systems is choices described in the prior art, and the exact procedure for injecting additives is therefore not described in more detail. In general, however, the temperature at the injection point / SCR catalyst 201 should be at least 200-2 ° C, preferably above 300 ° C in order to obtain the desired reaction rates, and the desired reduction of said first compound, such as one or more types of nitrogen oxides. .

According to the above Or, however, such systems are associated with certain disadvantages. If e.g. the temperature at the position in the after-treatment system where the supply of additives takes place Or too law, there is a risk that urea injected with the aid of the injection nozzle 305 instead may be directly evaporated by the passing exhaust stream hits relatively temperate cradles, whereby additives get stuck and start to build up crystals. As long as the vehicle is driven with varying and periodically higher loads with associated increases in the temperature in the finishing system, this crystal build-up will not have time to grow undesirably before the crystals are burned off 13 by the passing exhaust stream. If, on the other hand, the vehicle is driven for a time under relatively static conditions with relatively low load, with low temperatures in the exhaust system as follows, this crystal build-up can continue until the vehicle's performance is adversely affected by the increased surface resistance. The crystal build-up can also mean that the SCR system's ability to convert NO is affected by the supply of urea (such as spray image, quantity) due to that a coating in the form of lump formation arises. As above, this is solved according to the present invention by injecting the additive directly into the combustion chamber.

Internal combustion engines in vehicles of the type Or shown in Fig. 1A are often provided with controllable injectors to supply the desired amount of fuel at the desired time in the combustion cycle, as at a specific piston position (crank angle) in the case of a piston engine, to the combustion engine combustion chamber.

Fig. 4 schematically shows an example of a fuel injection system for the internal combustion engine 101 exemplified in Fig. 1A. The fuel injection system consists of a so-called Common Rail systems, but the invention is equally applicable to other types of injection systems. Fig. 4 shows only a cylinder / combustion chamber 401 with a piston 403 acting in the cylinder, but the combustion engine 101 in the present example consists of a six-cylinder internal combustion engine, and can generally consist of an engine with any number of cylinders / combustion chamber, such as e.g. . any number of cylinders / combustion chambers in the range 1-20 or more. The internal combustion engine further comprises at least one respective injector 402 for conventional combustion chamber (cylinder) 401. Each respective injector is thus used for 14 injection / supply of fuel in a respective combustion chamber 401. Alternatively, two or more injectors per combustion chamber may be used. The injectors 402 are individually controlled by respective actuators (not shown) arranged at each injector, which are based on received control signals, such as e.g. from the control unit 115, controls the opening / closing of the injectors 402.

The control signals for controlling the opening / closing of the actuators of the injectors 402 can be generated by any applicable control unit, as in this example by the motor control unit 115.

The motor control unit 115 thus determines the amount of fuel that is actually to be injected at any given time, e.g. based on the prevailing operating conditions of the vehicle 100.

The injection system shown in Fig. 4 thus consists of a so-called Common Rail system, which means that all injectors (and thus combustion chambers) are supplied with fuel from a common fuel line 404 (Common Rail), which by means of a fuel pump 405 is filled with fuel from a fuel tank (not shown) at the same time as the fuel in the pipe 404, also by utilizing the fuel pump 405, pressurized to a certain pressure. The highly pressurized fuel in the common tube 404 is then injected into the combustion chamber 401 of the internal combustion engine 101 at the opening of the respective injector 402. Several openings / rods of a specific injector can be made during one and the same combustion cycle, thus several injections can be made during one combustion cycle. Furthermore, the usual combustion chamber is provided with a respective pressure sensor 406 for emitting signals of a pressure radiating in the combustion chamber to e.g. the control unit 115. The pressure sensor can e.g. be piezo-based and should be so fast that it can emit crank angle-resolved pressure signals, such as e.g. at every 10, every 5th or habit crank angle degree or other applicable interval, such as e.g. an oftare.

With the aid of systems of the type shown in Fig. 4, the combustion during a combustion cycle in a combustion chamber can be controlled to a large extent, e.g. by utilizing multiple injections, where injection times and / or duration can be regulated, and where data from e.g. the pressure sensors 406 can be taken into account in the control. By utilizing data from e.g. the pressure sensor can also be estimated from the nitrogen oxides resulting from the combustion, whereby additives can be added to the combustion, e.g. depending on the estimated amount of resulting nitrogen oxides. Regarding the supply of additives, each combustion chamber, or only a part of the combustion chamber of the internal combustion engine, comprises an injector 410 by utilizing which additive can be supplied to the combustion chamber 401 from a tank 411.

Fig. 5 shows an exemplary method 500 for supplying additives to the combustion chamber according to the present invention, the method according to the present example being arranged to be performed by the motor control unit 115 shown in Figs. 1A-B.

Generally, control systems in modern vehicles consist of a communication bus system consisting of one or more communication buses for interconnecting a number of electronic control units (ECUs) such as the control unit, or controller, 115, and various components arranged on the vehicle. As such, such control systems may include a starting number of control units, and the responsibility for a specific function may be divided into more than one control unit. For the sake of simplicity, in Figs. 1A-B, only the motor control unit 115 in which the present invention is implemented in the embodiment shown is shown. However, the invention can also be implemented in a control unit dedicated to the present invention, or in whole or in part in one or more other control units already existing in the vehicle. In view of the speed at which calculations according to the present invention are carried out, the invention can be arranged to be implemented in a control unit which is specially adapted for real-time calculations of the type as below. Implementation of the present invention has shown that e.g. ASIC and FPGAlbsningar Lamped lining and selection can handle calculations according to the present invention.

The function of the control unit 115 (or the control unit / units in which the present invention is implemented) according to the present invention may, in addition to being dependent on sensor signals from the pressure sensor 202, e.g. depend on signals from other controllers or sensors. In general, control units of the type shown are normally arranged to receive sensor signals from different parts of the vehicle, as well as from different control units arranged on the vehicle.

The control is often controlled by programmed instructions. These programmed instructions typically consist of a computer program, which when executed in a computer or control unit causes the computer / control unit to perform the desired control, such as the steps of the present invention.

The computer program usually forms part of a computer program product, where the computer program product comprises an applicable storage medium 121 (see Fig. 1B) with the computer program stored on said storage medium 121.

The computer program may be non-volatile stored on said storage medium 121. Said digital storage medium 121 may 17 e.g. is made by 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, the computer program being executed by the control unit. By changing the instructions of the computer program, the behavior of the vehicle in a specific situation can thus be adapted.

An exemplary control unit (control unit 115) is shown schematically in Fig. 1B, wherein the control unit may in turn comprise a bending unit 120, which may be constituted by e.g. ndgon appropriate type of processor or microcomputer, e.g. a Digital Signal Processor (DSP), one or more Field-Programmable Gate Array (FPGAs) circuits or one or more circuits with an Application Specific Integrated Circuit (ASIC) function. The calculating unit 120 Or connected to a memory unit 121, which provides the calculating unit 120 e.g. the stored program code and / or the stored data calculation unit 1 need to be able to perform calculations. The calculation unit 120 is also arranged to store partial or final results of reports in the memory unit 121.

Furthermore, the control unit is provided with devices 122, 123, 124, 125 for receiving and transmitting input and output signals, respectively. These inputs and outputs may contain waveforms, pulses, or other attributes, which of the input signals 122, 125 may be detected as information for processing the calculation unit 120. The devices 123, 124 may send output signals or arranged to convert calculation results from the calculation unit. 120 to output signals for experience to other parts of the vehicle control system and / or the 18 component (s) for which the signals are intended. Each of the connections to the devices for receiving and transmitting input and output signals, respectively, may be constituted by one or more of a cable; a data bus, such as a CAN bus (Controller Area Network bus), a MOST bus (Media Oriented Systems Transport), or any other bus configuration; or by a wired connection.

Returning to the process 500 shown in Fig. 5, the process starts in step 501, in which it is determined whether the supply of additives according to the invention to the combustion chamber for nitrogen oxide reduction is to be carried out. The regulation according to the invention can e.g. be arranged to be carried out continuously as soon as the internal combustion engine 101 is started. According to one embodiment, injection of additives into a combustion chamber is performed only if the injection is carried out by a combustion during the same combustion cycle.

The method according to the present invention thus consists of a method for supplying additives to the combustion chamber of the combustion engine 101 while combustion takes place in said combustion chamber 201 in combustion cycles. As Or edge Or the term combustion cycle is defined as the steps a combustion at an internal combustion engine includes, such as e.g. the two-stroke engine's two-stroke engine and the four-stroke engine's four-stroke engine, respectively. The term includes Oven cycles where no fuel is actually injected, but where the internal combustion engine is driven at a certain speed, such as by the vehicle's drive wheel via the driveline at e.g. relaxation. Ie. In addition to no injection of fuel, a combustion cycle still takes place for e.g. each tvd vary (for four-stroke engine), or e.g. each vary (two-stroke engine), which rotates the output shaft of the internal combustion engine. The corresponding grille Oven other types of internal combustion engines. In step 502 it is determined whether a combustion cycle has or will be started, and when Si is the case the procedure proceeds to step 503, where an amount of nitrogen oxides resulting from the combustion is estimated.

In general, it is important that the supply of fuel to the combustion chamber, bide regarding quantity and pi which sat, ie. the one or more fuel injections to be performed during the combustion cycle are normally predefined, e.g. depending on the work (torque) that the internal combustion engine must perform during the combustion cycle.

Thus, fuel injection is normally performed according to an injection schedule where a plurality of injections may be arranged to be performed during one and the same combustion cycle. Combustion in connection with these industry injections will give rise to the resulting nitrogen oxides.

According to the present invention, during the combustion cycle, substantially continuous erasing pressure is established in the combustion chamber by using the pressure sensor 406, as at applicable intervals, e.g. every 0.1 degree crank angle.

The process of combustion in a combustion chamber can be generally described with the pressure change in the combustion chamber which the combustion gives rise to. The pressure change during a combustion cycle can be represented by a pressure pair, ie. a representation of how the pressure in the combustion chamber varies during combustion.

Thus, in step 503, the pressure pf in said combustion chamber 401 is substantially continuously determined by utilizing said pressure sensor 206 while combustion is paging in the combustion chamber. By utilizing the pressure change, generated nitrogen oxides NO during the combustion cycle can be estimated by utilizing applicable calculations, where a method of performing the calculation is exemplified below. Alternatively, other models with a corresponding function can be applied.

It is generally the case that nitrogen oxides NO in a combustion process are mainly formed for three different reasons. On the one hand, the industry may include nitrogen, whereby nitrogen will be released during combustion and At least form nitrogen gas N2 and nitrogen oxides NOR. This type of NOR formation can, in certain types of combustion and depending on the type of industry, account for a large part of the total amount of nitrogen oxides NO generated during the combustion. As explained below, however, this type of NOx formation can be disregarded during normal combustion according to e.g. the diesel cycle. Another call to NOR formation consists of so-called prompt NOR formation, but this cold can be generally disregarded if the impact is small in relation to other colds. A third cold, which in normal combustion is also the main cause of NOR formation during combustion at high combustion temperatures, consists of thermal formation of NOR, which can account for in the order of 90-95% or more of the NOR formation during the combustion cycle.

The formation of NOR is thus strongly dependent on the combustion temperature, and the actual formation of thermal NO can be described on the selection edge e.g. according to three main reactions (the undocumented Zeldovich mechanism): N2 + 0, NO + NN + 02, NO + 0 (1) N + OH, NO + H, cidr thus the reaction rate Or strongly temperature dependent, and there also the temperature dependence itself Or 21 ' cant, whereby by means of knowledge cm (substance) the amount of the constituent substances as well as the temperature the amount of nitrogen oxides formed NO can be estimated.

According to the present invention, the NO2 formation is estimated by utilizing the above chemical compounds, eq. (1), and by using an estimate of additional combustion data. The calculation therefore requires both knowledge of the available amount of nitrogen gas N2 and oxygen 02 and also knowledge of access to water H. These can be obtained from the combustion chemistry of combustion, which is known to those skilled in the art, and at which required amount of fuel and combustion air and possibly. exhaust gas feed is bachelor, whereby in combination with the fact that the composition of the industry is normally bachelor the quantities for those in eq. (1) the substances can be calculated.

An estimation of the combustion temperature is also required in order for the amount of nitrogen oxides generated NO to be estimated, since the reaction rate is temperature dependent. Likewise, pressure and / or average temperature in the combustion chamber are required in order to be able to estimate released nitrogen gas and oxygen, respectively, during combustion chemistry.

When estimating the amount of nitrogen oxides formed NOx, knowledge of the temperature of the combustion itself is therefore required. The temperature is higher in the part of the combustion chamber where combustion occurs, and the combustion chamber can be considered as consisting of two zones, (Jar combustion takes place in one zone, with high temperature in this zone as follows, while no combustion, with lower resulting temperature, takes place in Thus, at each instant, an average temperature in the combustion chamber is obtained which is below the temperature of the combustion at which combustion takes place.In order to be able to carry out the desired determination of the temperature of the combustion, knowledge of the heat release during combustion is also required.

This can be determined in different ways. For example. can, as described below, the heat release by estimation can be predicted by using a combustion model. This is exemplified in the Swedish patent applications described below. In these applications, the next part of a combustion is estimated, while according to an embodiment of the present invention, pressure signals from the pressure sensor 406 can be used to calculate the heat release during combustion.

The heat release during combustion can then be expressed as: dQ1 = pdV + Vdp + dQH, (2) Ddr dQ is released heat, p constitutes the pressure in the combustion chamber, V constitutes the volume of the combustion chamber, while dV constitutes the volume change of the combustion chamber.

V (co), this. the volume of the combustion chamber as a function of crank angle, can advantageously be tabulated in the dV memory of the control system or alternatively calculated in an appropriate manner, whereby even this can be determined.

C (t) C r = P = Pddr C and / or C are produced and C (t) Cp —R are tabulated for different molecules, and because the combustion chemistry is known, these tabulated values can be used together with the combustion chemistry to alarm 23 each. molecules (eg water, nitrogen, oxygen, etc.) effect on e.g. the total Cp value, whereby this can be determined for the calculations above with good accuracy. Alternatively, Cp and or C can be approximated p1 suitably. dp emits the pressure change in the combustion chamber, which is determined by the pressure sensor 406. dQHT represents the heat released during combustion, which can be determined in the manner described in the prior art by, for example, Woschni. In this case, the sight can also be taken to black body radiation in the combustion chamber in a concise manner. Swedish patent application 1350510-2, entitled "PROCEDURES AND SYSTEMS FOR REGULATING AN COMBUSTION ENGINE IV" describes a method for estimating released heat during an ongoing combustion. The method shown in this application can be applied according to the present invention. Furthermore, the procedure shown in the said application can be simplified by no estimation of the pressure according to the present embodiment is required, but pressure signals from the pressure sensor 406 can be used during the current combustion cycle up to the time below (Jar maximum amount of nitrogen oxides is considered to have been generated. the heat release can be estimated before a combustion.

According to the present example, however, the heat release can be estimated according to eq. (2) by utilizing signals from the pressure sensor 406. Fig. 6 shows, as a rough approximation, how the heat release 603 can be changed during a combustion cycle. Instead of expressing the combustion process as a function of time, it is instead expressed as a function of crankshaft row T. Fig. 6 also shows how the modeled NOx amount 601 resulting from the combustion changes during the combustion cycle, as well as how the average temperature 602 in the combustion chamber changes during the combustion cycle.

The pressure change p as a function of crank angle degree cp in a cylinder (combustion chamber) for a combustion cycle can be obtained as above by using the sensor signals from the pressure sensor 406. Furthermore, by using fixed pressure, the temperature for the part of the combustion chamber where no combustion takes place can be estimated by using of estimated pressure and by utilizing eq. (3), cid the temperature of the part of the combustion chamber where no combustion takes place is expressed as: Tn + 1 = Tn - \ K 1 Pn + 1 (3) Pn, cid /. Tr o can be the corresponding combustion air temperature for e.g. the time / crank angle position when the valves are closed after the supply of combustion air.

Furthermore, n, n + 1, etc. constitute consecutive times or crank angle positions.

K = 1, whereby also K can be determined as stated in fer 7 above.

By utilizing eq. (3) the temperature for that part of the combustion chamber can thus be determined (where no combustion pag is determined, where this temperature is affected by pagan combustion by the effect of the heat release on the pressure, which is reflected in the signals emitted from the pressure sensor, which in turn affects the temperature according to eq. When a combustion takes place, the heat release will give rise to a temperature rise in the part (s) of the combustion chamber where combustion takes place.This temperature rise, which is added to the temperature determined according to eq. (3) to obtain the combustion temperature, can be calculated. out of relation: dQ = inC pdT (4), cidr dQ constitutes the heat release, which can be determined as above. m is formed by combustion mass (ie fuel + air + EGR which is involved in the combustion), which is also determined as above, Cp, ie specific heat capacity, which can also be calculated as above, which means that the temperature rise is the phase of the combustion at a given ferrous mass and we d given Cp value.

Thus, by using equ (4), dT and thus nT can be determined, whereby the increase generated by the combustion at the usual time / crank angle position can be added to the temperature for the part of the combustion chamber where no combustion takes place, and which is given by eq. (3), to obtain the combustion temperature.

Thus, when the combustion temperature has been estimated, concentrations and / or absolute amounts of emitted N2 and O2 can be calculated by using the combustion chemistry, then, by using eq. (1) and its combustion temperature-dependent, generated nitrogen oxides NOx can be successively estimated and accumulated over the combustion cycle. The modeled nitrogen oxides are generated in principle until the maximum combustion temperature has been reached, or some time thereafter, indicated by the crank angle position T1 in Fig. 6.

Thus, in parallel with the estimation of the resulting nitrogen oxides, it can be determined whether Tmax for the combustion cycle has been reached, step 504, wherein, if so, the process proceeds to step 505 for determining the amount of additive for injection into the combustion chamber 201 using the injector 410, where applicable amount of additive for injection e.g. can be determined by using the known chemical compounds in the reaction between additives and nitrogen oxides. For example. the amount of additive can be determined as a stoichiometric amount of additive, i.e. the amount of additive required to completely convert the amount of nitrogen oxides. The amount of additive that is supplied to the combustion chamber can Oven e.g. consists of any applicable proportion of the stoichiometric quantity, such as in excess of or less than that quantity. For example. it may be unwise to reduce nitrogen oxides to a certain extent NOviss, whereby a smaller amount can be added. For example. a quantity can be added which is expected to mean that the vehicle's emissions comply with the applicable regulatory regulations where the vehicle is driven.

Alternatively, the quantity may be arranged to exceed the stoichiometric quantity e.g. in order to obtain a high reaction rate. The set can also be arranged to be less than a stoichiometric set, e.g. only a certain reduction is required or desired in the combustion chamber. further reduction can, if necessary, e.g. achieved by using an SCR catalyst as above.

According to one embodiment, the temperature of the combustion chamber is used above, i.e. the temperature pair 602 in Fig. 6, when determining 27 the applicable amount of additive as the reaction rate is strongly temperature dependent, the amount of additive thus e.g. can be determined as a function of one or more of the resulting nitrogen oxides, pressure in the combustion chamber, temperature in the combustion chamber.

According to one embodiment, the amount of resulting NON is successively estimated, whereby it is determined that it has a night maximum and / or begins to decrease, as at or after the position in Fig. 6, which also normally occurs via other chemical reactions than in reaction with additives, e.g. With a significantly lower reaction rate, the applicable amount of additive for delivery can be determined.

The additive is then injected in step 506, the process then returning to step 501 for re-determination of a subsequent combustion cycle. According to the present invention, the amount of resulting nitrogen oxides during a combustion cycle can thus be estimated, whereby an amount of additive adapted to the amount generated can be injected into the combustion chamber to effect reduction of the nitrogen oxides already in the internal combustion engine without high temperature and catalyst requirements. The present invention thus has the advantage that the need for SCR catalyst can be completely eliminated, or alternatively at least reduced. According to one embodiment, additives can be injected. Upstream of an SCR catalyst if necessary, where e.g. a smaller SCR catalyst On which may otherwise be possible to use, but in many cases the need for SCR catalyst disappears completely when using the present invention. Furthermore, problems with crystal formation etc. due to low temperatures as above are also completely or to a large extent avoided according to the present invention. 28 According to one embodiment, injection of additives is not performed unless the average temperature of the combustion chamber exceeds the flake applicable temperature. 700-750 ° C. This embodiment thus requires knowledge of not only the temperature of the combustion as above, but also the average temperature, i.e. curve 602 in Fig. 6, for the color combustion chamber. This average temperature 602 can e.g. is estimated according to what is described in the Swedish patent application 1350507-8, where it is described in detail how the average temperature in a combustion chamber can be estimated by using, among other things, the pressure in the combustion chamber, which can be obtained with the pressure sensor 406.

According to the method shown in the said application, an estimation is performed for the coming time, and this estimation can also be applied to the present invention so as to predict by estimating the applicable amount for injection even before the generated nitrogen oxides have reached a maximum level. In this case, the model shown in the said application, or other applicable model, of the combustion can be used.

According to one embodiment, however, the fact is used that pressure signals from the pressure sensor 206 representing the actual reddening pressure in the combustion chamber can be used until the amount of nitrogen oxides has reached a maximum amount of nitrogen oxides, i.e. position 21 in Fig. 6, whereby estimation is not required, and where the heat release e.g. can be estimated as above, and where the average temperature can be determined e.g. according to the general gas law. Thus, according to one embodiment, it can be determined that the temperature Or is sufficiently high for the desired reactions to occur, such as e.g. a radiating average temperature in the combustion chamber exceeding 700-750 ° C, where this average temperature can thus be determined by utilizing the general gas layers on account 29 and as also shown in the said application, whereby undesired crystal formation can be avoided.

According to one embodiment, suedes are injected only if the temperature exceeds the temperature, shown in Fig. 6, the suedes interval P2 constituting a "window" in which the injection of additives should take place. This "window" can also e.g. be limited in terms of maximum temperature, ie. injection can be arranged to take place only if the temperature in the combustion chamber is below any applicable temperature, whereby suedes P1 can be shifted to the right in Fig. 6. Furthermore, it should be noted that the injection of additives need not be carried out exactly where it actually burns a combustion chamber, but the injection can take place at any place in the combustion chamber, e.g. with the secondary condition that said average temperature does not fall below e.g. Tlim.

According to one embodiment, the method shown in the said Swedish patent application 1350507-8 can also be applied so that before e.g. position plestimate whether the average temperature will be sufficiently high for injection to be performed, and if it is found that this is not the case, e.g. an additional fuel injection is performed based on this estimation in order to raise the temperature in the combustion chamber to enable injection of additives.

If this injection is performed sufficiently late in the combustion cycle, the injection will not contribute to NOx formation but will raise the temperature. When applying such extra injection, this can be arranged to be of a predetermined size, but it can also be arranged to be determined e.g. by using estimation according to the procedure shown in the said Swedish patent application 1350507-8 to determine, for example, the applicable amount of fuel for injection, separately or together with the injection of additives, may obtain the desired temperature.

According to the embodiment described so far, estimation of the resulting amount of nitrogen oxides has been performed during the current combustion cycle, whereby also an amount of additive based on the estimated resulting amount of nitrogen oxides is supplied.

According to one embodiment, instead, nitrogen oxides are estimated during a combustion cycle, in which case, based on this estimation, injection of additives is carried out during one or more subsequent combustion cycles. This has the advantage that the estimation can be performed more carefully.

According to a simplest form of the invention, no estimation of nitrogen oxides is performed, but additives are injected into the combustion chamber at the appropriate time, where e.g. injected quantity instead may be arranged to depend on the quantity of fuel supplied to the incineration, alternatively a standard quantity can always be applied, e.g. as long as at least a minimum amount of fuel is injected. According to a preferred embodiment, however, an estimation of the resulting nitrogen oxides is performed.

Furthermore, the present invention has hitherto been described in connection with a process (Jar nitrogen oxide formation is estimated up to the time during the combustion cycle when the nitrogen oxides are considered to have formed. As above, this is indicated by the crank angle position 91. According to the illustrated embodiment, the control system thus has knowledge of pressure pressure). the combustion chamber 401 up to the position 91 as this has been determined by using the pressure sensor 406. When the nitrogen oxide formation is considered to have 31 completed, the amount can be estimated using actual pressure development and an appropriate amount of injection injection during the subsequent combustion cycle is determined based on estimated NOR.

Furthermore, according to the embodiment shown, radiating temperature in the combustion chamber 401 can be estimated by utilizing actually detected pressure change, whereby the appropriate time for injection of additives can be determined so that injection takes place when the temperature in the combustion chamber 401 is at the desired temperature range.

According to an embodiment of the invention, the injection of additives is carried out instead of at an earlier stage during the combustion cycle, such as e.g. in whole or in part before the combustion is started or stopped, such as e.g. in whole or in part before the industry injection is started. An example of such a procedure is shown in Fig. 7. Fig. 7 shows the pressure p in the combustion chamber 401 as a function of crank angle degree T. In Fig. 7, solid line 701 shows the pressure change in a combustion chamber when combustion is not performed, i.e. the pressure change the combustion chamber undergoes due to the reciprocating movement of the piston when the inlet and outlet valves are closed, respectively. cp-rvc represents the degree of crank angle at which the inlet valves are closed and (PEvo the degree of crank angle at which the exhaust valves are opened and atmospheric pressure atm or radiating combustion air pressure suedes racier. m rTipc represents the byre dead center of the piston. Dashed line 702 represents the fundamental change in combustion). this example combustion is substantially drilled at the lyre of the piston (PTDr. The sloping surface 703 represents suede dead center the pressure change the combustion gives rise to. According to the above 32 examples the injection of additives has been carried out during the part of the combustion cycle following the crank angle position maximum pressure has been reached, which essentially corresponds to the position where the temperature will also be maximum during the combustion cycle.

According to one embodiment, the additive is added instead before the combustion is started, ie. meanwhile from the time the inlet valves are closed at Tivc until the combustion is started, ie. in the present example in the interval Tivc - (VIDc. For example, the supply of additives may be arranged to be carried out with some applicable sub-interval of the interval (pivc (PTDc, such as between the time TB-cpc in Fig for example, be set so that the temperature in the combustion chamber exceeds any applicable temperature.

According to the example shown in Fig. 6, the NOR content can be estimated substantially when the combustion has been completed, whereby measured pressure can be used in the calculation model according to the above for calculation of generated nitrogen oxides NOR. In the case where the additive is supplied before the combustion is started, an actual pressure pair 701 cannot be used up to the position (such as TA in Fig. 7) where the nitrogen oxides can be considered to have formed to also estimate the nitrogen oxide presence after the combustion because this combustion has not yet happened. At the same time, it is unfortunate that a large amount of additives are supplied which is adapted to the large number of nitrogen oxides which are later formed during the combustion cycle. The applicable amount of additives can be determined in several different ways. According to one embodiment, generated nitrogen oxides NO are estimated as above during a combustion cycle, the additive being supplied first during a subsequent combustion cycle. This procedure can e.g. applied when the ratios for several consecutive combustion cycles are essentially the same. 33 According to one embodiment, however, an estimation of the nitrogen oxides NO formed during the subsequent part of the combustion cycle is performed, whereby additives are added before the combustion has actually taken place and based on an estimated outcome of the combustion. The amount of nitrogen oxides generated can be estimated according to the above equations, but knowledge of the upcoming pressure change in the combustion chamber is therefore required because there is no knowledge of this. The pressure change in the combustion chamber can e.g. is estimated according to the above-referenced Swedish patent application 1350511-0, where a procedure is described for estimating the amount of generated nitrogen oxides, whereby the combustion can then be regulated based on the expected amount of nitrogen oxides.

According to the present invention, the method exemplified in the said application can be used to estimate the amount of nitrogen oxides generated, where the said application exemplifies how the pressure change during the next part of the combustion cycle can be estimated, this estimated pressure can be used in the calculations described above. As described in the aforementioned application, knowledge of the industry load that will be injected during the combustion cycle and other injection takes place is required in the calculation. However, this usually consists of data as also described above in connection with calculating the heat release due to the combustion, which is thus described in more detail in the Swedish application 1350510-2, which also predicts by estimating the heat release for the next part of the combustion cycle, which thus performed when the calculations are performed by an estimated pressure, is described in detail.

Thus, by using the method shown in Swedish patent application 1350511-0, the expected amount of formed nitrogen oxides NO can be estimated before the time TB in Fig. 7, whereby A suitable amount of additive for injection can be determined before / at the position TB in Fig. 7. , wherein this amount can then be injected into the combustion chamber, for example during the interval TB_Tc. The amount of additive for supply can e.g. issued by stochiometric or other applicable quantity. For example. it may be unwise to add a larger amount of additive than is ideally required to reduce the expected amount of nitric oxide as additives may be "burnt" during combustion and clamed to reduce the efficiency of the NOx reduction.

Furthermore, an injection of additives before combustion takes place will affect the actual combustion process. This is due, as will be appreciated, partly to the addition of additional substance to the combustion chamber. In addition, the additive is usually a liquid, where the liquid to a relatively large extent may contain e.g. water. The supplied liquid will evaporate completely or to a large extent, where energy evaporates during the evaporation, with the result that the temperature in the combustion chamber will be reduced.

In addition, a dissociation effect occurs when water molecules in gaseous form are divided into hydrogen and oxygen, respectively, where energy is used for the molecular division. This in turn will affect the combustion, where a reduced temperature may result in a smaller amount of nitrogen oxides being generated, with the result that a smaller amount of additive is required solely because of this condition.

Thus, the calculation of the expected formation of nitrogen oxides NO should take into account the required amount of additives, so the additive should also be included in the calculation. This in turn may require that iterations be required to find an amount of additive for supply which corresponds to the amount of nitrogen oxides which will be generated in a combustion which takes place after the additive has been supplied.

Regarding the calculations, the additive will affect specific heat capacity in the combustion chamber and thus affect gamma y in the equations above. More specifically, the effect of the change in specific heat capacity can be obtained by calculating specific heat capacity at constant pressure Cp and at constant volume Cry, respectively, where in the calculation below exhaust gas liner, EGR, is treated.

Heat capacities are tabulated for different chemical substances and basic substances in tables issued by NASA, and interpolated as a function of temperature, where the average temperature of the combustion chamber is used. This temperature can e.g. is estimated according to what is described in the Swedish patent application 1350507-8, where it is described in detail how the average temperature in a combustion chamber can be estimated by using, among other things, the pressure in the combustion chamber, which can be estimated as above. General Or the specific heat capacity at constant pressure Cp tabulated in the form: c (T) = a1T-2 + a2T-1 + a3 + a4T + aT2 + a6T3 + a7T4 () The specific heat capacity for constant volume, Cs ,, can then be calculated as Cv = Cp — R, whereby thus gamma y can be calculated. NO.r gamma y has been calculated, the amount of nitrogen oxides generated can be estimated as above. The effect of the additive on gamma y is described below.

As mentioned, when calculating gamma y Oven, it may be advantageous to take his view into the case where EGRAterforing is performed, ie. when a part of the exhaust gases from the combustion is returned to the inlet side of the combustion engine, which affects the chemical composition of the combustion chamber. Regulation of the EGR Feedback normally constitutes a separate regulation, but as described below, it can be advantageous to adapt the EGR Feedback based on the amount of additives that are added. When EGR feedback is applied, e.g. the following relationship is applied to estimate specific heat capacity at constant pressure for EGR recycled gas, where a and b are the number of carbon atoms and water atoms in the industry used to propel the vehicle, ie. Cyb, and ddr constitute the lambda value: acPco22CPif20 + (a) aA9 / -1) Cp 02 + 3,773 gi CpN2) C EGR = b aF-2 + (4.773 / 19i —1) (a +) Corresponding calculation of specific heat capacity at constant volume of clean air consists of: 1 CA = —4,773 0.773c (T) + c, r) (T)) p IRp ,. 2-2 In order to obtain a correct gamma value, the respective heat capacity according to Eq. (8), where EGR% constitutes the EGR content: Cp = CpAIR * (1— EGR%) + CpEGR * EGR% (8) The EGR content can e.g. is determined as an EGR content determined during a previous combustion cycle. Alternatively, the EGR content can be determined via e.g. emission calculations, ddr e.g. Carbon dioxide calculations can be used to determine the proportion of combustion air that is made up of recycled exhaust gases. For example. this can be done by feeding the carbon dioxide content at the inlet to the combustion chamber or at the outlet of the combustion chamber or further downstream in the after-treatment system, whereby the EGR content can be calculated in a manner known to those skilled in the art. The EGR return thus emits a variable which is not calculated specifically for each combustion cycle, but which is normally available in the vehicle's control system, where this is calculated at applicable intervals. In general, the regulation of the EGR experience is much slower than the regulation of the present invention.

Regarding the effect of the additive on specific heat capacity, and thus gamma y, this can be determined by the following calculation: Cp m additive (T) = c, (T) * (1 - additive part) + Cp Wool agent (T) * additive part (9), where c - p additive (T) can be bachelor's and is tabulated. Alternatively, cptimedeAT) can be determined in the same manner as described forEGR above by knowledge of the composition of the additive. Gamma y can then be determined as: Y = Cp with additive Cv with additive (10), where: Cv with adjuvant = Cp with additive R By using advanced y which has been compensated for injection of additives before combustion, suede's expected generated nitrogen oxides during combustion can be estimated. as above, whereby it can be stated that a smaller amount of additive is required, whereby a new calculation for a smaller amount of additive can be performed, etc. etc. Applicable amount of additive for injection before combustion can be sued 38 until the desired amount of additive in relation to related amount formed nitrogen oxides are obtained in the calculations.

When adding additives to the combustion according to the present invention, there are also additional aspects that should be considered. For example. According to the above, an EGR feed of some of the exhaust gases formed during combustion is normally applied. EGR feedback generally has a positive (decreasing) effect on NOx formation. The supply of additives will result in a changed exhaust gas composition compared to the case when additives are not supplied. For example. For example, the additive as above may consist in part of water, whereby it is also likely that a larger proportion of water will normally be present in the resulting exhaust stream. This means that a regulation of the EGR feedback based on the supply of additives may be required. For example. it may be required that the EGR feed is reduced due to a relatively higher water content in the exhaust stream, which gives a better effect with respect to the NO reduction, but with the risk that undesirably high water content can be obtained in the combustion chamber if the EGR feed becomes too high in relation to water content .

The regulation of the EGR feedback can be performed in any suitable way, where e.g. The impact of the EGR feedback on the specific heat capacity as above can be taken into account and whereby the EGR feedback e.g. can be regulated based on these calculations. It is generally the case that regulation of the EGR feed is slow (of the order of seconds) compared with the regulation carried out according to the present invention where calculations are performed during the current combustion cycle and where 39 calculations can be performed in e.g. one hundredth of a second, one thousandth of a second or a shorter time.

Furthermore, when supplying additives to the combustion chamber, there are additional aspects that should be taken into account.

The pressure in a combustion chamber can amount to relatively high pressures, such as maximum pressures in the order of 200-300 bar. Normally, fuel injection is performed with significantly higher pressure than the combustion chamber pressure, such as e.g. 1500-2500 bar, whereby changes in the combustion chamber pressure become substantially negligible in relation to the high fuel injection pressure. This means that the injected amount of fuel can be determined with good accuracy. However, the use of high pressures is usually associated with high costs, for which reason it may be undesirable to carry out the injection of additives at substantially lower pressures, such as e.g. pressure in the same order of magnitude as radiating combustion chamber pressure. This in turn means that for a certain opening time of the injection nozzle for injecting additives, due to the back pressure of the combustion chamber, different amounts can be supplied for one and the same opening time depending on the prevailing combustion chamber pressure. Thus, the injection time of the additive can be arranged to be controlled based on radiating combustion chamber pressure where this e.g. can be determined by using the pressure sensor 406.

Thus, at higher radiating combustion chamber pressures, a longer opening time can be used compared to if radiating combustion chamber pressures are lower, where, as will be appreciated, radiating combustion chamber pressures will depend on the crank angle position at which the injection of additive takes place.

Furthermore, the present invention comprises a welding in which liquid such as a liquid partially containing water is supplied to the combustion chamber of the combustion engine. This water supply may require that certain protection aspects / Atgarder may need to be considered. According to oyan, in the case of injection of additives after combustion, a lower temperature limit has been exemplified in order for the desired conversion to take place. There may also be restrictions on riding during the combustion cycle. Injection of additives should be done for other reasons. For example. it may be unreasonable for the piston to be at a certain number of crank angle degrees from the upper dead center when injection takes place so that not too much of the cylinder wall is exposed during the injection with risk of rock hit with flushing of oil film as fault and clamed associated risk of unwanted wear .

Furthermore, the supply of additives can e.g. be arranged to be stalled if the speed of the vehicle is less than the speed of any yis, or if the vehicle becomes stationary, or if for some reason there is a risk that the internal combustion engine within the map will be stalled ay. In dive-like situations, it can be unfortunate that e.g. the yatten incidence in the internal combustion engine system has time to be reduced before the internal combustion engine is switched off to avoid water-associated damage. According to an embodiment of the invention, the supply of additives may be arranged to be stopped by the speed of the vehicle below any applicable speed and the ambient temperature of the vehicle below e.g. non degrees Celsius in order to prevent the yacht from cooling in the system after the internal combustion engine has been switched off with the risk of freezing as a result. Furthermore, the above embodiments can be combined with a method which adapts the combustion as the combustion progresses, where the combustion is regulated based on some applicable criterion. In e.g. Swedish patent application 1350511-0 describes a process in which the combustion during a combustion cycle is regulated based on a predicted and during the current combustion cycle the amount of resulting nitrogen oxides estimated. According to one embodiment, the process according to the invention can be combined with the process shown in the said application, wherein the amount of resulting nitrogen oxides NO before the supply of additives can be arranged to be regulated by regulating the combustion. Furthermore, the amount of additive for supply to the combustion chamber can be arranged to be determined based on an estimation of the resulting nitrogen oxides as described in the said Swedish patent application 1350511-0.

Furthermore, the process can be arranged to be interrupted when the temperature in the combustion chamber has reached the maximum temperature during the combustion, since essentially all nitrogen oxide generation is likely to have occurred before this time, for which subsequent regulation instead e.g. can be carried out completely according to the selected injection schedule, or alternatively carried out based on some other applicable criterion.

The invention has been exemplified above in a manner in which a pressure sensor 406 is used to determine a pressure in the combustion chamber, and by means of which temperature and nitrogen oxide generation as above can be estimated. An alternative to using pressure sensors can instead be the use of one (or more) other sensors, such as e.g. high-resolution ion current sensors, knock sensors or strain gauges, whereby the pressure in the combustion chamber can be modeled by utilizing sensor signals from such 42 sensors. It is also possible to combine different types of sensors, e.g. to obtain a more accurate estimation of the pressure in the combustion chamber, and / or to use other applicable sensors, where the sensor signals are converted to the corresponding pressure for use in control as above.

The method according to the invention for regulating the internal combustion engine can also be combined with sensor signals from other sensor systems where resolution at the crank angle level is not available, such as e.g. other pressure sensors, NOx sensors, NE13 sensors, PM sensors, oxygen sensors and / or temperature sensors etc., which input signals e.g. can be used as input parameters when estimating e.g. expected pressure / temperature by utilizing data-driven models in whole or in part instead of models of the type described above. For example. For example, signals from a NOx sensor arranged downstream of the combustion engine can be used in determining the applicable amount of additive for supply to the combustion chamber. In this case, e.g. an undesired high NOx content indicated by the NON sensor causes an increase in the amount of reducing agent added.

Furthermore, the present invention has been exemplified above in connection with vehicles. However, the invention is also applicable to arbitrary vessels / processes where nitrogen oxide control as above is applicable, such as e.g. water or aircraft with combustion processes as above.

It should also be noted that the system can be modified according to various embodiments of the method according to the invention (and vice versa) and that the present invention is not in any way limited to the above-described embodiments of the method according to the invention, but relates to and includes all embodiments of the appended independent the scope of protection of the requirements. For example. For example, the invention is applicable to the injection of any additive into the combustion chamber of the internal combustion engine 43, where this additive may be intended for the reduction of nitrogen oxides, or one or more other compounds.

Claims (42)

A method of controlling an internal combustion engine (101), said combustion engine (101) comprising at least one combustion chamber (201) and means (202) for supplying fuel to said combustion chamber (201), wherein combustion in said combustion chamber (201) ) takes place in combustion cycles, the process Or being characterized by: During a first combustion cycle and by using first sensor means (406), determining a first parameter value representing a quantity with respect to said combustion chamber (201); and 3. supplying to said combustion chamber (201) said first amount of additive. The method of claim 1, wherein said first parameter representing a quantity relating to said combustion chamber (201) outputs a quantity relating to the combustion in said combustion chamber (201). A method according to claim 1 or 2, wherein said additive is an additive for reducing at least one first substance (NO) resulting in ferrous combustion in said combustion chamber (201). A method according to any one of claims 1-3, further comprising: 1. using said first parameter, estimating a first mat on at least one first substance (NO) resulting from combustion during said first combustion cycle, and 2. based on said first middle, determine the said first amount of additive for supply to the said combustion chamber. The method of claim 4, further comprising estimating said first mat during said first combustion cycle. The method of claim 4 or 5, further comprising: 1. estimating said first center on at least one first substance (NO) resulting from combustion during a first portion of a first combustion cycle, and 2. based on said first center adding said additive. to the said combustion chamber during a subsequent part of the said first combustion cycle. The method of claim 4 or 5, further comprising: 1. estimating said first center on at least one first substance (NO) resulting from combustion during a first portion of a first combustion cycle, and 2. based on said first center administering said additives. to the said combustion chamber at least in part before combustion is introduced during the said first combustion cycle. The method of claim 4 or 5, further comprising: 1. estimating said first center on at least one first substance (NO) resulting from combustion during a first portion of a first combustion cycle, and 2. based on said first center adding said additives. to the said combustion chamber at least in part before combustion is terminated during the said first combustion cycle. 46 A method according to any one of claims 6-8, further comprising: 1. in said estimating said first center at least one first substance (NO) resulting in combustion during said first part of said first combustion cycle, estimating the effect of supply of additives before namnda farbranning pi namnda forsta mitt. A method according to any one of claims 6-9, further comprising: 1. determining a first amount of additive to be supplied to said combustion chamber, 2. estimating a second center of at least one first substance (NO) resulting from combustion during said first combustion cycle upon supply of said first amount of additive before said combustion, and 3. correct said first amount of additive for supply to said combustion chamber based on said second center. The method of claim 10, further comprising: 1. iteratively estimating the center of at least one first substance (NO) resulting from combustion during said first combustion cycle, and 2. iteratively correcting said first amount of additive based on said determined center until a center at least one first substance (NO) resulting from combustion during said first combustion cycle fulfills a first condition. A method according to any one of claims 4-11, wherein said estimated first medium constitutes an estimated content of said 47 at least one first substance (NO) for the exhaust gases resulting from the combustion. A method according to any one of claims 4-12, wherein said estimated first center constitutes an estimated resulting amount of at least one first substance (NO) for at least a portion of said first combustion cycle. A method according to any one of claims 4-13, further comprising supplying said additive to a combustion cycle following said first combustion cycle based on said first center. A method according to any one of claims 1-14, wherein said first parameter value represents a pressure present in said combustion chamber (201). A method according to any one of claims 4-14, further comprising: - estimating the resulting amount of at least one first substance (NO) At least in part based on an estimated combustion temperature. The method of claim 16, wherein said combustion temperature is estimated at least in part by estimating a heat release during said combustion. The method of claim 17, further comprising estimating said heat release by utilizing knowledge of an industry quantity intended for supply to said combustion. 48 A method according to any one of claims 16-18, further comprising estimating the amount of available nitrogen gas (N2) and the amount of available oxygen gas (02) at least in part by utilizing knowledge of an industry quantity intended for supply to said combustion, wherein the amount of at least one first substance (NOW is estimated at least in part based on the said available amounts of nitrogen gas and oxygen, respectively. A method according to any one of claims 16-19, wherein said combustion temperature is estimated at least in part based on a pressure in said combustion chamber (201). A method according to any of claims 16-20, further comprising estimating said combustion temperature as a sum of an estimation of a temperature increase caused by combustion in relation to a first temperature, and an estimation of said first temperature, wherein said first temperature is a estimated temperature for unburned gas in the said combustion chamber. The method of any of claims 4-21, further comprising estimating the generated amount of said at least one first substance (NO at least in part using a Zeldovich mechanism. A method according to any one of claims 4-22, further comprising, when said first mat on said first substance (NOx) is estimated for said combustion: - interrupt estimation when estimation has been performed tram to a point where a maximum temperature during combustion is expected. 49 The method of any of the hazardous claims, further comprising: 1. determining whether the temperature of said combustion during said combustion cycle has reached maximum temperature during said combustion cycle, and 2. determining the amount of additive for supply to said combustion chamber when maximum temperature has been reached. A method according to any one of the preceding claims, further comprising determining a plurality of additives for supply to said combustion chamber at least in part based on one or more of the group: chemical relationships in the reaction between additives and nitrogen oxides, combustion chamber temperature, signals from a downstream internal combustion engine -sensor. A method according to any preceding claim, wherein exhaust gases resulting from combustion in said combustion chamber pass an SCR catalyst, further comprising injecting additional additives downstream of said combustion engine but upstream of said SCR catalyst. A method according to any preceding claim, wherein exhaust gases resulting from combustion in said combustion chamber pass an SCR catalyst, further comprising injecting additives into said combustion chamber for use at least in part for reduction in said SCR catalyst. A method according to any one of the preceding claims, wherein injection of additives into said combustion chamber is performed only if the temperature of the combustion chamber exceeds a first temperature. A method according to any one of the hazardous claims, further comprising, when the temperature of the combustion chamber is below a first temperature, an additional fuel injection is performed to raise the temperature in said combustion chamber before or simultaneously with said supply of additives. A method according to any one of the preceding claims, further comprising determining the amount of additives for supply to said combustion chamber at least in part based on the amount of fuel supplied to said combustion chamber. A method according to any one of the preceding claims, further comprising determining the amount of additive for injection individually for each cylinder. 32. A method according to any one of the preceding claims, wherein said control is performed for a plurality of consecutive combustion cycles. A method according to any one of the preceding claims, wherein said additive is an additive for reducing nitrogen oxides (NO) resulting from combustion in said combustion chamber (201). A method according to any one of the preceding claims, wherein said first mat of nitrogen oxides (NO) resulting from combustion during said first combustion cycle consists of a mat of resulting nitrogen monoxide (NO) and / or nitrogen dioxide (NO2). A method according to any one of the preceding claims, wherein said additive consists of an additive separate from said industry. 51 A method according to any one of the preceding claims, wherein said additive is a urea and / or ammonia-containing additive. A computer program comprising program code, wherein said program code is executed in a computer. Provides said computer performing the method of any of claims 1-36. A computer program product comprising a computer-curable medium and a computer program according to claim 37, wherein said computer program is included in said computer-curable medium. A system for controlling an internal combustion engine (101), said combustion engine (101) comprising at least one combustion chamber (201) and means (202) for supplying fuel to said combustion chamber (201), wherein combustion in said combustion chamber (201) comprises combustion (201). in combustion cycles, the process being characterized in that the system comprises: 1. means (115) arranged to, during a first combustion cycle and by using first sensor means (406), determine a first parameter value representing a quantity with respect to said combustion chamber (201). means (115) arranged to determine, by utilizing said first parameter value, a first amount of additive for supply to said combustion chamber, and 3. means (115, 410) arranged to supply to said said combustion chamber (201) said first additive. 52 A system according to claim 39, characterized in that said internal combustion engine comprises means for supplying additives to said combustion chamber. A system according to claim 39 or 40, characterized in that said internal combustion engine is constituted by one of the group: vehicle engine, marine engine, industrial engine. Vehicle (100), characterized in that it comprises a system according to any one of claims 39-41. FIG. 'IA 100 1- 13 .--- 104 103? , ---- 108 107 101? 106 200 .---- 1 2/7