SE1350506A1 - Method and system for controlling an internal combustion engine through control of combustion in an internal combustion chamber during the current combustion cycle - Google Patents

Abstract

The present invention relates to 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 the said combustion chamber (201) takes place in combustion cycles. The method Or may be characterized by: during a first combustion cycle, determining at least one first parameter value representing a quantity in combustion in said combustion chamber (201), based on said first parameter value, estimating a maximum combustion result during said first combustion cycle (combustion result) , and based on said estimated maximum pressure change rate regulate subsequent combustion. The invention also relates to a system and a vehicle. Fig. 3

Description

BACKGROUND OF THE INVENTION The present invention relates to internal combustion engines, and more particularly to a process for 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 prior art.

Concerning vehicles in general and at least in some heavy vehicles in particular, there is a constant development in pursuit of fuel efficiency and reduced exhaust emissions. Due to e.g. Increased government interests regarding pollution and air quality in e.g. In urban areas, emission standards and regulations have been developed in many jurisdictions. When driving heavy vehicles, such as trucks, buses and the like. Over time, the vehicle economy has also had an increasing impact on the profitability of the business in which the vehicle is used. In addition to the vehicle's acquisition cost, the main expense items for current operation of wages for the vehicle's driver, costs for repairs and maintenance as well as industry for propulsion of the vehicle. Thus, it is important for each of these areas to try to reduce the cost in the best possible way.

In addition to economic / environmental aspects as above, there are also additional aspects that should be taken into account when designing vehicles. For example. Driver comfort is important, perhaps especially for heavy vehicles, and starting work is also often put on 2 million passengers. This includes work with sound comfort, ie. minimization / optimization of, above all, unwanted noise / noise to which the driver is exposed when driving the vehicle, where loud or otherwise disturbing noises can have a negative effect on the driver's driving of the vehicle, e.g. by causing stress and / or fatigue.

Another aspect is the sound the vehicle emits to its surroundings, ie. how the vehicle's progress is audibly experienced in the environment in which the vehicle is driven. For example. In this respect, there may also be laws and regulations that regulate permissible sound emissions from vehicles.

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, wherein said internal combustion engine comprises at least one combustion chamber and means for supplying fuel to said combustion chamber, wherein combustion in said combustion chamber takes place in combustion cycles. The method is characterized by: during a first combustion cycle, determining at least one first parameter value representing a quantity for combustion in said combustion chamber, based on said first parameter value, said estimated maximum pressure change rate, regulate subsequent combustion.

As mentioned above, the sounds generated when driving a vehicle, and which are often considered to a large extent as unwanted noise, are an important parameter not only in the effort to achieve a good driving environment, but also from the environment in which the vehicle is driven. .

In vehicles, as is the case, many noises / noises are made, and a main source is the internal combustion engine.

The sound produced by an internal combustion engine depends to a large extent on the combustion in the combustion chamber of the internal combustion engine, and above all on the manner in which the pressure changes during combustion. In particular, the sound generated will largely depend on the pressure derivative during combustion, ie. the time derivative of a representation of the pressure, i.e. the rate at which the pressure changes. Unwanted sound can occur when the pressure changes, and especially when the pressure rises rapidly. Unwanted sound can also occur when the pressure rises to a high pressure.

According to the present invention, the combustion is regulated with respect to the manner in which the pressure changes during the combustion, such as e.g. by means of a control which aims to limit the maximum speed at which the pressure changes during combustion, in particular during an ongoing pressure rise, and which according to one embodiment also aims to limit the maximum pressure which arises during combustion. The control of the combustion can be arranged to be carried out individually for a conventional cylinder, and the combustion can be regulated for a subsequent combustion cycle based on information from one or more preceding combustion cycles.

According to one embodiment, the maximum pressure change rate that results during a 4 combustion cycle is estimated, the combustion combustion having a subsequent combustion cycle being regulated based on this estimation, and wherein the regulation at subsequent combustion cycles can be adjusted to avoid e.g. an undesirably high pressure change rate.

According to one embodiment, an ongoing combustion is regulated during a combustion cycle, the invention providing a control of an ongoing combustion process where control can be performed during ongoing combustion in order to e.g. prevent an undesired high pressure change rate from occurring.

The control according to the present invention can be achieved by establishing during a first part of a combustion cycle a parameter value regarding a quantity in the combustion, such as e.g. a pressure radiating in the combustion chamber. Based on this parameter value, such as e.g. a radiating pressure, then a expected maximum pressure change rate such as e.g. a maximum pressure increase speed and / or a maximum expected pressure is estimated, whereby the combustion during a subsequent part of the combustion cycle can be regulated with respect to the expected pressure change rate.

The combustion can e.g. is regulated by establishing an injection strategy for application in a subsequent injection during the combustion cycle, whereby in determining the injection strategy an expected maximum pressure change rate can be estimated, whereby an injection strategy, such as e.g. an injection strategy of a plurality of injection strategies, can be selected, where an injection strategy is chosen which is not expected to result in an undesired pressure development during the combustion. For example. an injection strategy can be selected which is expected to result in a maximum pressure change rate which is somewhat below the applicable threshold for the pressure change rate, where this threshold amounts to any applicable pressure change rate such as e.g. expected to result in a sound output level which in turn is below any applicable sound level, or meets another criterion regarding sound output.

The process of the present invention can e.g. implemented using 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 to which the present invention can be applied.

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

Fig. 2 shows the internal combustion engine of the vehicle shown in Fig. 1A in more detail.

Fig. 3 shows an exemplary method according to the present invention.

Fig. 4 shows an example of an estimated pressure pair for a combustion, as well as an actual pressure pair up to a first crank angle position.

Figs. 5A-B show an example of control in situations with more than three injections. Fig. 6 shows an example of an MPC control.

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 internal combustion engine 101 is controlled by the vehicle's control system via a control unit 115. Likewise, the clutch 106, which e.g. can be constituted by an automatically controlled clutch, and the gearbox 103 of the vehicle's control system by means of 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 of the internal combustion engine 101 (eg cylinders).

Furthermore, internal combustion engines in vehicles of the type 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 degree) in the case of a piston engine, to the internal combustion engine combustion chamber. Fig. 2 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. 2 shows only a cylinder / combustion chamber 201 with a piston 203 acting in the cylinder, but the internal combustion engine 101 is the present example of a six-cylinder internal combustion engine, and can generally be 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 combustion engine further comprises at least one respective injector 202 for each combustion chamber (cylinder) 201. Each respective injector is used suedes for injection (supply) of fuel into a respective combustion chamber 201. Alternatively, two or more injectors per combustion chamber may be used. The injectors 202 are individually controlled by respective actuators (not shown) arranged at the respective injector, which are based on received control signals, such as e.g. from the control unit 115, controls the opening / closing of the injectors 202.

The control signals for controlling the opening / closing of the actuators of the injectors 202 can be generated by any applicable control unit, as in this example by the motor control unit 115.

The motor control unit 115 suedes 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. 2 thus consists of a so-called Common Rail system, which meant that all injectors (and thus combustion chambers) are supplied with fuel from a common fuel line 204 (Common Rail), which by means of a fuel pump 205 is filled with fuel from 8 a fuel tank (not shown) at the same time as the fuel in the pipe 204, also with the aid of the fuel pump 205, is pressurized to a certain pressure. The highly pressurized fuel in the common tube 204 is then injected into the combustion chamber 201 of the internal combustion engine 101 at the opening of the respective injector 202. Several openings / rods of a specific injector can be made during one and the same combustion cycle, thus several injections can be made during a combustion cycle. Furthermore, each combustion chamber is provided with a respective pressure sensor 206 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 5 or every crank angle or other applicable range, such as e.g. an oftare.

With the aid of systems of the type shown in Fig. 2, 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 frail e.g. the pressure sensors 206 can be taken into account in the control.

According to an embodiment of the present invention, the combustion of a subsequent combustion cycle is regulated based on a previous combustion cycle, i.e. the calculation from a previous combustion cycle is used in controlling a subsequent combustion cycle. According to the invention, e.g. injection times and / or duration of respective injection and / or injected industry volume during an ongoing combustion cycle based on data from the current combustion cycle. 9 As mentioned above, the noise which the operation of an internal combustion engine generally gives rise to depends to a large extent on the combustion in the combustion chamber of the internal combustion engine, and in particular on the mode in which the pressure changes during combustion. According to the invention, the combustion is regulated with respect to the pressure change that arises during the combustion, such as e.g. by means of a regulation aimed at limiting the maximum pressure derivative during the combustion, ie. the maximum speed at which the pressure changes, and di especially at pressure boiling. According to one embodiment, the maximum pressure allowed to arise in the combustion chamber is regulated.

Fig. 3 shows an exemplary method 300 according to the present invention, in which the method according to the present example is arranged to be performed by the motor control unit 115 shown in Figs. 1A-B.

General Modern vehicle control systems 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 in 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, Figs. 1A-B show only the motor control unit 115 in which the present invention is implemented in the embodiment 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 performed, 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 FPGA solutions are lighted for and selection can handle calculations according to the present invention.

The function of the control unit 115 (or the control unit (s) to 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 controller causes the computer / controller to perform the desired control, such as the process 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. 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, the computer program being executed by the control unit. By following the instructions of the other 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 in turn may comprise a bending unit 120, which may be constituted by e.g. any ldmplig type of processor or microcomputer, e.g. a Digital Signal Processor (DSP), one or more Field-Programmable Gate Array (FPGAs) or one or more circuits with an Application Specific Integrated Circuit (ASIC). The bending unit 120 is connected to a memory unit 121, which provides the bending unit 120 e.g. the stored program code and / or the stored data recovery unit 1 need to be able to perform calculations. The coverage unit 120 is also arranged to store partial or final results of coverage 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 input and output signals may contain waveforms, pulses, or other attributes, which of the input signals receiving devices 122, 125 may be detected as information for processing the output signal 120. The output signals 123, 124 for transmitting output signals are arranged to convert output results from the input device. 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, may be 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 flagon other bus configuration; or by a wireless connection.

Returning to the method 300 shown in Fig. 3, the process starts in step 301, where it is determined whether the inventive control of the combustion process 12 is to be performed. The regulation according to the invention can e.g. be arranged to be performed continuously as soon as the internal combustion engine 101 is started. Alternatively, the regulation can be arranged to be performed e.g. as long as the combustion engine combustion is not to be regulated according to any other criterion. For example. there may be situations where it is necessary for regulation to be carried out based on factors other than the sound emitted in the first place. According to one embodiment, control of the combustion is performed simultaneously with respect to emitted sound during combustion and at least one additional control parameter. For example. a balancing can be done, where the prioritization of the control parameters when fulfilling the desired control result e.g. may be arranged to be controlled according to any applicable cost function.

The method according to the present invention thus consists of a method for controlling the internal combustion engine 101 while combustion takes place in said combustion chamber 201 in combustion cycles. As Or edge, 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 combustion engine spirit 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. every two 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 302 it is determined whether a combustion cycle has or will be started, and in that case the procedure proceeds to step 303 at the same time as a parameter in the representative injection number is set equal to one. In step 303, an injection scheme / control alternative is established which is expected to result in a desired pressure development during the combustion cycle, such as e.g. an injection scheme that is expected to limit the maximum pressure change rate during the combustion cycle.

In general, the supply of the multitude of industries both in terms of quantity and in what way, 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 is to perform during the combustion cycle, since modification of the established injection schedule is not performed during an ongoing combustion cycle according to prior art. Predefined injection schedules can e.g. are tabulated in the vehicle's control system for a starting number of operating cases, such as different engine speeds, different work required, different combustion air pressures, etc., where tabulated data e.g. may have been produced by appropriate tests / feeds yid e.g. development of an internal combustion engine and / or vehicle, whereby the applicable injection schedule / control alternative can be selected based on prevailing conditions, and where the injection schedule can be selected or be pre-adapted to e.g. result in a predetermined pressure change rate that is less than an undesirably high pressure change rate.

These injection schedules / control alternatives can consist of the number and properties of the injections in the form of e.g. time (crank angle law) for start of injection, length of injection, injection pressure, etc., and thus are stored for a start number of operating cases in the vehicle's control system, and e.g. be advanced / fed with the grind to result in a pressure change rate that does not become undesirably high. The injections can also be produced for the purpose of fulfilling other miles, such as delivering the desired work, resulting in a certain maximum heat loss, a certain exhaust temperature, etc., whereby the injections are suedes can be produced based on a weighting of several parameters.

According to the present embodiment, therefore, in step 303, such a predetermined injection schedule is applied, where this predetermined injection schedule is selected, e.g. by table look-up, based on prevailing conditions and desired work done by the internal combustion engine, where the desired done work is normally controlled by some superior / other process, such as e.g. based on a request for power from the driver of the vehicle and / or a cruise control system.

According to one embodiment, the injection schedule is determined entirely according to e.g. the calculations shown below, where e.g. different pre-defined injection schedules can be compared with each other to determine a most preferred injection schedule, but in the calculation example exemplified below, the calculations are applied only after injection has started during the combustion cycle.

Since specific assumed conditions are likely to result in the same preferred injection schedule habit, it may be advantageous to select an injection schedule for a combustion cycle by flaking type of cleavage and clamed to reduce the calculation load, calculating as follows only after injection has been started.

In addition to the following examples of how the injection schedule can be determined, other models with a corresponding function can alternatively be applied.

Thus, according to the present embodiment, in step 303, a predetermined injection schedule is established at the beginning of the combustion cycle, wherein control according to the invention is performed only after fuel injection has been started during the combustion cycle, as only after at least one injection has been performed during the combustion cycle, or after has been published.

Thus, fuel injection is normally performed according to a predetermined schedule, where a plurality of injections may be arranged to be performed during one and the same combustion cycle. This means that the injections can be relatively short. For example. Injection systems with 5 fuel injections / combustion occur, but the number of fuel injections can also be significantly larger than said, such as e.g. on the order of 100 fuel injections during a combustion cycle. The number of possible injections is generally controlled by the speed at which the organs with which the injection is performed have, i.e. in the case of Common Rail systems of how quickly the injectors can be opened shut down.

According to the present example, at least two fuel injections are performed during one and the same combustion cycle, but as has been named and as shown below, several injections can be arranged to be performed, as well as only one.

The injection schedule is thus in the present example determined in advance in order to obtain a pressure development which meets set criteria with respect to pressure change rate during combustion. A first injection is injected, and in step 304 it is determined whether said first injection has been performed, and if so, the procedure proceeds to step 305, where it is determined whether all the injections have been performed.

Since this is not the case in the present example 16, the procedure proceeds to step 306 while being straightened up with a final injection. Furthermore, by using the pressure sensor 206, it is determined continuously, as at applicable intervals, e.g. every 0.1-10 crank angle degrees, riding pressure in the combustion chamber.

The process of combustion 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 spdr, ie. a representation of how the pressure in the combustion chamber varies / decreases during combustion. As the combustion progresses as expected, the pressure in the combustion chamber will be equal to the initially estimated, but as soon as the pressure deviates from the estimated pressure, the rate at which the pressure has changed will also deviate from the estimated pressure change. In addition, the subsequent part of the combustion cycle, and thus pressure reduction, will be affected due to the fact that changed conditions in the combustion chamber coincide with colored conditions at e.g. a subsequent injection.

If the combustion after the first injection has been carried out exactly as expected, the conditions in the combustion chamber will correspond to the conditions intended for the injection, as well as the resulting pressure change (pressure sprout below) in the combustion chamber will correspond to the expected point pressure change. However, as soon as the conditions deviate from the intended conditions, the pressure change during combustion will deviate from the expected pressure change. Likewise, the subsequent part of the combustion will also be disrupted because the conditions riding in the combustion chamber, e.g. with respect to 17 pa pressure / temperature, at the next injection will not correspond to expected conditions.

In practice, the actual pressure changes during combustion (pressure pair) will also most likely deviate from the predicted pressure pair during combustion due to e.g. deviations from the modeled combustion. This is illustrated in Fig. 4, where a predicted pressure pair 401 for an example injection scheme is shown (very schematically), i.e. the expected pressure pair for the combustion chamber when injection is performed according to the selected injection profile.

This prediction of the pressure pair can e.g. performed as described below.

Fig. 4 also shows an actual pressure pair 402 up to the crank angle position T1, which constitutes a rowing position after said first combustion has been carried out. In step 306, the pressure po in the combustion chamber is determined by using the pressure sensor 206 after the first injection has been made, at the crank angle position T1. Preferably, the pressure in the combustion chamber is determined substantially continuously, as e.g. at each crank angle, every tenth crank angle or at other appropriate intervals throughout the combustion. As can be seen in Fig. 4, the actual pressure pair up to T1 deviates from the estimated pressure pair 401, likewise the actual pressure po at T1 deviates from the estimated pressure Pest est according to the pressure pair 401. The above meant that the pressure derivative probably also deviated from related to the crank angle position (pt.

Since the pressure p (pl in the combustion chamber after the first injection has been carried out differs from the corresponding estimated pressure n iscp1 est at the crank angle position T1 18, the conditions in the combustion chamber at the time of the next injection insp2 will differ from the predicted proportions after to deviate from the predicted combustion if the previously established injection schedule would still be used.

Thus, it is not all certain that the desired limitation of the pressure travel speed will be met during the combustion cycle. Thus, it is also not certain that it is the originally established injection schedule that constitutes the most preferred injection schedule in the effort to achieve a combustion with undesired regulation of the pressure demand rate.

In step 307, it is determined whether the expected pressure demand rate dp_pred is expected to exceed any applicable maximum. to step 304 for performing the next injection, whereupon a new estimation of dp is performed. If, on the other hand, dp_pred is expected to exceed dp_thres, the procedure proceeds to step 308 to establish a new injection schedule in order to regulate the pressure demand rate, such as e.g. with the means to try to limit the pressure demand rate so as not to exceed dp_thres. The regulation can e.g. carried out according to the calculations shown below, or alternatively according to other applicable calculations with a corresponding purpose, and repeated as follows during the current combustion cycle in order, if necessary, to require the injection schedule during the combustion if the conditions actually saving in the combustion chamber deviate. or during ongoing injection.

When estimating the expected maximum pressure change rate according to the invention, a model is applied, which describes the pressure change that occurs during combustion. This model can yara of different type, and e.g. consists of a data-driven model such as e.g. dpdV dt = f (mitinjection strategy) Y dt), where p is measured or estimated pressure, where uinjectionstrategy is a control signal, ie. injection schedule, where y generally constitutes the heat capacity ratio, ie. y = P = P Cp — R where Cp and / or C, are generally produced and tabulated for different molecules, and since the combustion chemistry is known, these tabulated values can be used together with the combustion chemistry to thereby calculate each molecule (eg water , nitrogen, oxygen, etc.) impact on e.g. the total Cp value, whereby this can be determined for the calculations above with good accuracy, in advance or during e.g. ongoing combustion. Alternatively, Cp and or C, can be approximated in an appropriate manner. constitutes the volume change of the combustion chamber over time, dt which e.g. can be determined with the help of VW.

V ((p) is the volume of the combustion chamber as a function of the crank angle, can advantageously be tabulated in the control system memory or alternatively calculated in an appropriate way, whereby it can also be calculated, and thus also multiplied by the combustion engine's radiating speed dp Thus the pressure can be changed. such a model, which can be produced by determining results for a starting number of input parameters, whereby it can then be tabulated for a starting number of conditions, such as different loads, speeds, air pressures, etc., as is the edge for the person skilled in the art.

Another alternative, which also constitutes the alternative used in the present example, is the use of a physical model of the change in pressure during combustion in the combustion chamber. This model can be any suitable model, and according to the present example, a heat release equation is applied as below.

Estimation of the pressure on variation during combustion can then be performed as follows. The pressure p radiating in the combustion chamber can be determined by using said pressure sensor, whereby continuous sensor signals can give the measured value of the pressure p at suitably taken intervals / crank angle degrees to estimate dp for the part of the combustion which has already elapsed, and whereby an actual can be estimated for the part of the combustion that has already elapsed based on actual pressure data. The change in pressure can be determined as a function of time, as indicated above, but can also be expressed in dt dp crank angle degrees, i.e. which meant an elimination of the combustion engine speed dependence on the calculations. In this case, the desired maximum pressure change rate LIE can e.g. dcp is stored for different speeds n to clamed e.g. represent a desired pressure change over time. Alternatively 21, dp can e.g. The present invention strives to actively reduce the rate of pressure change in the combustion chamber, if necessary, by estimating the color pressure change rate (pressure derivative) for the subsequent part of the combustion cycle, e.g. . a maximum advanced pressure change rate can be determined, whereby the color burn can be regulated in order to keep the maximum pressure change rate below any applicable pressure change rate.

This also means that the pressure change can be estimated for a number of different scenarios during combustion, such as different injection schedules, where the respective injection schedule will give rise to a specific pressure pair, such as e.g. the pressure pair shown in Fig. 4, and also clammed pressure derivatives.

When estimating the pressure pair, a model of the pre-combustion can be used, and, as is the matter to the person skilled in the art, the pre-combustion can be modeled according to eq. (1): dQ = Kcalibrate (Q fuel - Q) (1) where Kcalibrate is used to calibrate the model. Kcalibrate consists of a constant which is usually in the order of 0-1, but may also be arranged to assume second values, and which is determined individually cylinder by cylinder or for a certain engine or engine type, and depends in particular on the design of the injectors nozzles (diffusers ). 22 Qfi, u tgOr energy value for injected industry quantity, Q utgOr combustion energy quantity. The combustion dQ Or is thus proportional to the injected amount of fuel minus the amount of fuel consumed so far. The combustion dQ can alternatively be modeled by using another applicable model, where e.g. Other parameters can also be taken into account. For example. The combustion Above can constitute a function that depends on a model Over the turbulence that arises during the supply of air / fuel, which can affect the combustion to varying degrees depending on the amount of air / fuel supplied.

Regarding the industry injections, these can e.g. is modeled as a sum of step functions: U = (i) (t (tinj. start) k) (P (t (tinj. end) k) (2) k = 0 Bransleflodet matt i tillford mass m at an injection k, ie how the fuel enters the combustion chamber during the time window u when the injection is performed, expressed in the time that elapses below the crank angle degree p -interval that the injector Or is open, for a specific injection k can be modeled as: dm = f (m) u (3) where m constitutes injected industry volume, and f (m) eg depends on injection pressure, etc. f (m) can, for example, be measured or estimated in advance.

The energy value 0 LHV for the industry, such as diesel or petrol, is generally stated, whereby such a general statement can be used. The energy value can be specified above by 23 e.g. industry's manufacturers, or be approximated for e.g. a country or region. The energy value can also be arranged to be estimated by the vehicle's control system. With the energy value, eq. (1) is released and the heat release Q as the combustion proceeds is determined.

Furthermore, by utilizing a predictive heat release equation, the pressure change in the combustion chamber during the entire combustion can e.g. estimated as: dp = (aQydiT) (y-1) thp (4) cicpy-11 'dcp), (Jar y gives the heat capacity ratio as above. p is obtained by integrating equ. (4) according to: P Pinitial + f dP Pinitial + 1V (C1 (2y dV \ (y - 1) P) 1 dy) (5) dy) y — dy) \ Dar Pinitai constitutes an initial pressure, which before the start of the combustion step of the combustion e.g. may be the ambient pressure of non-turbocharged internal combustion engines, or a radiating combustion air pressure yid turbocharged engine. When estimation is performed at a later time during the combustion cycle, such as estimation in step 307 after an injection has been performed, Pinitiate can be formed by the cid radiating and aided by the pressure sensor 206 determined pressure, nozzle. po In the present example. Thus, both the pressure p and the pressure derivative in the combustion chamber can be estimated for the entire color combustion, ie. a variant curve corresponding to the curve 401 in Fig. 4 can be estimated, and the corresponding curve for dp.

Thus, by utilizing eq. (4) dp, either as a function of crank angle or time by multiplying by 24 revolutions as above, is estimated for the remainder of the combustion cycle, or even for an entire combustion cycle in the estimation performed before fuel injection is started, with dp at each iteration of equations 4-5 can be compared with dp_thres father to determine whether the pressure change rate dp is expected to exceed dp_thres during combustion.

If so, the procedure proceeds as above to step 308 to establish a new injection strategy, since regulating the pressure in the combustion chamber e.g. can be performed by regulating the fuel injection, and by performing estimation of the pressure derivative in step 308, a number of different injection schedules are obtained with e.g. varying injection times and / or injection lengths and / or number of injections, estimated pressure derivatives for different injection alternatives can be compared and an injection schedule can be established as possible to ensure that dp_thres is below during combustion, preferably with the additional condition that the working condition is still required.

Thus, in step 308, an injection schedule may be established, such as an injection schedule among a plurality of defined injection schedules, where this injection schedule may be determined individually cylinder by cylinder based on sensor signals from at least one pressure sensor in each combustion chamber.

Regarding the mentioned injection schedules, it can e.g. there are a plurality of predefined injection schedules, whereby calculations of the above type can be performed for each of these available injection schedules. Alternatively, the calculations can be performed for the injection schedules that for some reason are most likely to result in a low / desired pressure change rate.

So far, entire injection schedules for the remaining incineration have been evaluated, but the evaluation can also be arranged to be performed for the next injection only after a previous injection, whereby later injections can be handled afterwards. The injection scheme selected in step 308 can thus consist of only the next injection.

Once the injection schedule has been selected in step 308, the procedure returns to step 304 for performing the next injection, in which case it also causes a combustion, and clams a heat release and a pressure gauge, where the above will probably deviate from the previously predicted pressure gauge. This also means that the combustion Oven during subsequent injections is likely to be affected by radiating conditions in the combustion chamber when the injection is started.

Thus, in step 308, after a subsequent injection has been performed, a new injection strategy for subsequent injections, alternatively the subsequent injection, can be calculated using the above equations, the procedure then proceeding to step 304 for carrying out the subsequent injection. injection strategy developed in step 308, still taking into account the work to be carried out during combustion, which is thus normally controlled by some overriding process, e.g. in response to a request for a certain driving force from the vehicle's driver or another function in the vehicle's steering system, such as e.g. a cruise control function. The control can thus be arranged to be performed after each injection 26 and flare after all the injections have been performed. Repeat the procedure from step 305 to step 301 for controlling a subsequent combustion cycle. According to one embodiment, however, the process is stopped as soon as the maximum pressure of the combustion has been reached, which can be determined as below. The sound emitted during combustion depends above all on the pressure build-up and to a lesser extent on the subsequent pressure drop. For this reason, the control can thus be interrupted when the maximum pressure of the combustion has been reached.

In the above calculations, after each injection, the current pressure determination po is used by using the pressure sensor 206 as the initial as above to predict pressure change rate to determine a new injection schedule according to the current conditions of the combustion chamber, but now provided with additional data. a bit into the combustion. Ie. po after the first combustion and correspondingly set po for subsequent injections, whereby Pinitial is changed in calculations during the combustion cycle, and whereby the fuel injection is adapted to radiating conditions after each injection, with the consequence that the injection schedule can be changed after each injection.

The present invention thus provides a method which adapts the combustion as the combustion proceeds, and generally comprises, based on a first parameter value determined after a first part of the combustion has been carried out, controlling the subsequent part of the combustion during one and the same combustion. on the pressure derivative during the combustion process. According to the above, the pressure change rate can thus be estimated for a number of different alternative injection schemes for intermittent injections, whereby an injection scheme which results in the most advantageous, such as e.g. the lowest pressure change rate can be selected when performing subsequent injection. In cases where several injection schemes / control alternatives meet the set conditions, other parameters can be used to select which of these is to be used. There may also be other reasons to simultaneously regulate even based on other parameters.

For example. In addition, based on pressure change rate, injection molding can also be selected in part based on one or more of the perspectives pressure amplitude, heat loss, exhaust temperature, exhaust work in the combustion chamber, or nitrogen oxides generated during combustion as additional criteria, such determination can be performed according to any of the following. patent applications.

Specifically, the parallel application "PROCEDURE AND SYSTEM FOR CONTROLING AN COMBUSTION ENGINE V" discloses a procedure for controlling subsequent combustion based on an estimated maximum pressure amplitude.

Furthermore, the parallel application "PROCEDURE OCR SYSTEM FOR CONTROLING AN COMBUSTION ENGINE II" shows a method for controlling during a first combustion cycle a subsequent part of combustion during said first combustion cycle with respect to a temperature resulting in said subsequent combustion.

Furthermore, the parallel application "PROCEDURE OCR SYSTEM FOR CONTROLING AN COMBUSTION ENGINE III" shows a procedure for regulating combustion during a first combustion cycle during a subsequent cycle of the said first combustion cycle with respect to a work performed during combustion.

Furthermore, the parallel application "PROCEDURES OF A COMBUSTION ENGINE SYSTEM CONTROL IV" discloses a method for regulating combustion during a first combustion cycle during a subsequent part of said first combustion cycle with respect to a representation of a desired consumption.

Furthermore, the parallel application "PROCEDURE OCR SYSTEM FOR CONTROLING AN COMBUSTION ENGINE VI" shows a procedure for estimating during a first combustion cycle a first mat on nitrogen oxides resulting from combustion during said first combustion cycle, and based on the first combustion part of ndmnda first combustion cycle.

As mentioned above, the maximum pressure achieved during combustion can be used as an additional criterion.

In this case, eq. (5) above is used. By integrating the relationship, the maximum pressure expected to be reached during the estimation can be obtained by performing the integration as long as p (k + 1)> p (k), ddr k, k + 1 etc. constitute successive times / crank angle positions. As long as the pressure rises, the integration is thus continued, while the integration can be interrupted at (k + 1) According to the method described above, the injection schedule at the beginning of the combustion cycle has been determined based on tabulated values, but according to one embodiment, the injection strategy can already be determined before the industry injection is started in the manner described above, thus also the first injection is performed according to the above schedule.

The regulation has hitherto been described in a manner in which the properties of a subsequent injection are determined based on prevailing conditions in the combustion chamber after the previous injection. However, the control can also be arranged to be performed continuously, whereby pressure determinations can be performed with the aid of the pressure sensor also during pagan injection, and whereby the injection schedule can be calculated and corrected by others until the next injection is started. Alternatively, even the ongoing injection can be affected by protruding changes in the injection schedule even in cases where a number of shorter injections are performed. For example. an ongoing injection can be interrupted if the pressure change rate becomes too high. The injection can also consist of a single longer injection, whereby changes of ongoing injection can be performed continuously, e.g. by so-called rate shaping, e.g. by changing the opening area of the injection nozzle and / or the pressure at which the fuel is injected based on estimates and the measured pressure value during the injection. Furthermore, fuel supply during combustion can include two fuel injections, where e.g. only the second or both injections are regulated e.g. with the help of rate shaping. Rate shaping can also be applied in the case where three or ten injections are performed.

Regarding the injection strategies to be evaluated, these can be developed in different ways. For example. different distributions between injections can be evaluated, and e.g. can injected industry volume be redistributed between subsequent injections and / or can the injection time be changed for one or more subsequent injections, where the view can be taken to ev. restrictions with regard to e.g. minimum permissible length or amount of fuel for an industry injection.

Instead of evaluating a number of specific injection schedules, the method may be arranged to perform e.g. the above calculations for a number of conceivable scenarios, where the calculations can be performed for different injection lengths / quantities / times for the different injections, with corresponding changes in released energy.

The more industry injections that are carried out during a combustion cycle, the tier parameters can be changed, while tiring work should be maintained. At an initial number of injections, the regulation can therefore be relatively complex, since an initial number of parameters can be varied and thus would need to be evaluated. For example. a very initial number of injections can be arranged to be performed during one and the same combustion cycle, such as a dozen, or even about a hundred injections.

In such situations, and in addition to others as above, there may be several substantially equivalent injection strategies, 31 which result in essentially the same pressure derivatives, or which meet set requirements / requirements for the pressure derivative. This introduces an unwanted complexity into the calculations.

According to one embodiment, a control is applied where the nearest injection / injection is considered a separate injection at the time, and then subsequent fuel injections as a single additional "virtual" injection, whereby fuel can be distributed between these "two" injections in a way that the pressure derivative during the first combustion is not expected to exceed desired levels. This is exemplified in Fig. 5A, where the injection 501 corresponds to the inspl as above, the injection 502 corresponds to the insp2 as above, and where the remaining injections 503-505 are treated as a single virtual injection 506, i.e. the injection 506 is treated as an injection with an industry quantity substantially corresponding to the total industry amount for the injections 503-505, and where distribution can take place between the injection 502 and the virtual injection 506. By proceeding in this way, the displacement which takes place between insp2 and subsequent injections needs is not specifically distributed between the injections 503-505, but is distributed at this stage between the injection 502 and the "virtual" injection 506, respectively.

After the injection 502 has been performed, if necessary, the procedure is repeated as above with a new determination of the injection schedule to reduce the pressure derivative if necessary, but with the injection 503 as a separate injection, see Fig. 5B, and the injection 504, 505 together form a virtual injection during distribution as above.

In Fig. 5A, the virtual injection 506 is three injections, but as will be appreciated, the virtual injection 32 506 from the beginning may include more than three injections, such as 10 injections or 100 injections, depending on how many injections are intended to be made. is carried out during the combustion cycle, the procedure being repeated until all the injections have been carried out. According to one embodiment, however, the process is interrupted when maximum pressure has been reached by the above-mentioned shells.

It is also possible to use e.g. an MPC (Model Predictive Control) control when controlling according to the invention.

An example of an MPC control is shown in Fig. 6, where the reference curve 603 corresponds to the expected development of the pressure derivative at the heat release during the combustion cycle, i.e. the result of eq. (4) above for selected injection schedule. Curve 603 can e.g. consists of a realistically achievable (lowest) level for the pressure derivative during the combustion cycle at the current load and radiating speed, and can e.g. determined in advance, e.g. by applicable calculations and / or feeds on the motor type, whereby this data can be stored in the control system memory as a function of e.g. speed and load.

This also means that the combustion does not have to be controlled only against a pressure derivative radiating as usual, but can also be arranged to be controlled against a related pressure derivative, such as e.g. curve 603 in Fig. 6, whereby habit injection may be intended to result in a combustion corresponding to curve 603.

The solid curve 602 up to time k represents the actual development of the pressure derivative which has hitherto arisen and which has been calculated as above with the aid of actual data from the crank angle-dissolved pressure sensor. Curve 601 represents the estimated, i.e. expected, the development of the pressure derivative based on the predicted 33 injection profile. Dashed injections 605, 606, 607 represent the predicted control signal, i.e. the injection profile used is applied, and 608, 609 represent already challenging injections.

The predicted injection profile is updated at appropriate intervals, such as e.g. after each challenge injection, to reach the final value which is sought and given by the reference screw 603, and where the next injection is determined based on the prevailing conditions in relation to the estimated pressure development.

Thus, the present invention provides a method which allows a very good control of a combustion process, and which adapts the combustion during ongoing combustion to obtain a combustion with controlled pressure change and associated associated emitted sound.

According to the above, the combustion can be regulated during an ongoing combustion cycle. According to one embodiment, however, the estimation is performed for a combustion cycle, whereby a subsequent combustion cycle can then be regulated based on the estimation for the previous combustion cycle.

The invention has been exemplified above in a manner in which a pressure sensor 206 is used to determine a pressure in the combustion chamber. As an alternative to using pressure sensors, one (or more) other sensors can be used, such as e.g. high-resolution ion current sensors, knock sensors or strain gauges, whereby the pressure of the combustion chamber can be modeled by using sensor signals from such sensors. It is 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 34 sensor signals are converted to the corresponding pressure for use in control as above.

Furthermore, in the above description, only industry injection has been regulated. Instead of regulating only the amount of fuel supplied, the pressure during combustion can be arranged to be regulated by means of e.g. exhaust valves, whereby injection can be carried out according to a predetermined schedule, but where the exhaust valves are used to regulate the pressure in the combustion chamber.

Furthermore, the control can be performed with any applicable type of regulator, or e.g. using state models and state feedback (for example, line programming, the LQG method or similar).

The inventive method for controlling 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, NH3 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. pressure derivatives by using data-driven models instead of models of the type described above.

Furthermore, the present invention has been exemplified above in connection with vehicles. The invention is, however, also applicable to arbitrary vessels / processes where combustion 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.

Claims (37)

A method of controlling an internal combustion engine (101), wherein said internal combustion engine (101) comprises at least one combustion chamber (201) and means (202) for supplying fuel to said combustion chamber (201), said combustion in said combustion chamber (201). ) takes place in combustion cycles, the process being characterized in that: 1. during a first combustion cycle, determine at least one first parameter value representing a quantity for combustion in said combustion chamber (201), 2. based on said first parameter value, estimate a maximum pressure change rate and pressure resulting in said first combustion chamber (201), 3. based on said estimated maximum pressure change rate, regulate subsequent color combustion. The method of claim 1, wherein said subsequent combustion is part of said first combustion cycle. A method according to claim 1 or 2, further comprising determining said first parameter value during a first part of said combustion cycle, and wherein said subsequent combustion is constituted by a part of said first combustion cycle following said first part of said first combustion cycle. The method of claim 1, wherein said subsequent combustion is a combustion cycle following said first combustion cycle. 37 A method according to any one of the preceding claims, further comprising determining at least one control parameter for controlling said subsequent combustion, said control parameter being a control parameter where the estimated maximum pressure change rate when controlling according to said control parameter is less than an initial pressure change rate. A method according to any one of the preceding claims, further comprising determining at least one control parameter for controlling said subsequent combustion, said control parameter being a control parameter where the estimated maximum pressure during combustion when regulating according to said control parameter is expected to be less than a first pressure. A method according to any one of the preceding claims, further comprising: - in determining a control parameter for controlling said subsequent combustion, determining said control parameter as a control parameter which is expected to result in a requested work in said combustion. A method according to any one of the preceding claims, wherein in said control a pressure change rate resulting from said combustion cycle and / or said subsequent part of said combustion cycle is estimated by using one or more of: data driven model, empirical model, physical model. A method according to any one of the preceding claims, wherein a pressure change for said subsequent combustion is estimated by utilizing an estimation of a heat release during said combustion. 38 The method of claim 9, wherein said estimated pressure change is an estimated pressure pair. The method of claim 9 or 10, further comprising estimating said heat release based on the amount of fuel supplied to said combustion. A method according to any one of the preceding claims, wherein said first parameter value represents a pressure radiating in said combustion chamber (201). A method according to any preceding claim, further comprising controlling combustion during said subsequent portion of said first combustion cycle by controlling the supply of fuel to said combustion chamber (201). A method according to any one of the preceding claims, further comprising: - estimating an expected maximum pressure change rate for at least two control alternatives for said subsequent combustion by utilizing said first parameter value, and - selecting a control alternative from said plurality of control options for controlling said afterburning. Combustion based on the said expected maximum pressure change rate. The method of claim 14, further comprising: - determining whether any of said control options constitute a control alternative (Jar estimated maximum pressure change rate when regulating according to said control alternative is less than an initial pressure change rate, and - if so, selecting a control alternative where 39 is the estimated maximum pressure change rate is less than said first pressure change rate. The method of claim 14 or 15, further comprising selecting the control alternative that is expected to result in the lowest pressure change rate during said subsequent combustion. A method according to any one of claims 14-16, wherein said control alternative consists of alternatives for supplying fuel during said subsequent part of said combustion cycle. A method according to any one of claims 14-17, wherein the supply of fuel to said combustion chamber (201) is regulated by controlling fuel injection by means of at least one fuel injector (202). A method according to any one of claims 14-18, wherein at least one fuel injection is performed during said subsequent part of said combustion cycle, wherein in said regulation the fuel quantity and / or injection length and / or injection pressure is regulated for said fuel injection. A method according to any one of claims 14-19, wherein at least two fuel injections are performed during said subsequent part of said combustion cycle, said combustion being regulated on top of said first of said at least two fuel injections. A method according to any one of claims 14-20, wherein in controlling said combustion at least three fuel injections are performed during said subsequent part of said combustion process, wherein in determining control parameters a first of said At least three fuel injections, remaining fuel injections are treated as a single fuel injection. injection. A method according to any one of claims 14-21, wherein controlling the combustion during said subsequent part of said first combustion cycle is performed at least in part by controlling injection of fuel to said combustion chamber (201) during an ongoing fuel injection. A method according to any one of claims 14-22, further comprising in controlling the injection of fuel into said combustion chamber (201) changing a distribution between fuel quantities between at least two fuel injections. A method according to any one of claims 14-23, further comprising applying a predetermined supply of fuel at the beginning of the combustion cycle, wherein control is performed after a first injection has at least started, but before fuel injection during said first combustion cycle has ended. A method according to any preceding claim, further comprising performing a first fuel injection to said combustion chamber (201) during a first portion of a first combustion cycle, and at least a second fuel injection during a subsequent portion of said combustion cycle, wherein second parameter parameters for said combustion parameters determined after the said first fuel injection has been carried out at least in part. A method according to any preceding claim, further comprising: - determining whether the pressure at said combustion 41 during said combustion cycle has reached maximum pressure during said combustion cycle, and - interrupting said process when maximum pressure has been reached. A method according to any one of the preceding claims, further comprising, when estimating a pressure change rate for said combustion: - interrupt estimating for said subsequent combustion when maximum pressure amplitude or maximum pressure change rate in said estimation has been determined. A method according to any preceding claim, further comprising controlling combustion during said subsequent portion of said first combustion cycle by controlling one or more valves operating at said combustion chamber (201). 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 preceding claim, wherein said first parameter representing a quantity in combustion in said combustion chamber (201) is determined at least at each crank angle, every tenth of each crank angle or every hundredth of each crank angle. A method according to any one of the preceding claims, wherein said first parameter is determined by using one or more of the group: cylinder pressure sensor, knock sensor, strain sensor, speed sensor, ion current sensor. 42 A method according to any one of the preceding claims, wherein said pressure change rate is a pressure cracking rate. A computer program comprising program code, which, when said program code is executed in a computer, causes said computer to perform the procedure according to any of claims 1-32. A computer program product comprising a computer-printable medium and a computer program according to claim 33, wherein said computer program is included in said computer-printable medium. A system for 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), combustion in said combustion chamber (201). in combustion cycles, the method being characterized in that the system comprises: 1. means (115) for determining during a first combustion cycle at least one first parameter representing a quantity in combustion in said combustion chamber (201), 2. means (115) for being based on said first parameter was to estimate a maximum pressure change rate resulting during said first combustion cycle and in said combustion chamber (201), and means (115) for regulating subsequent combustion based on said estimated maximum pressure change rate. A system according to claim 34, characterized in that said internal combustion engine consists of nAgon from the group: vehicle engine, marine engine, industrial engine. 43 Vehicle (100), characterized in that it comprises a system according to claim 34 or 35.