CN118434962A - Method and apparatus for controlling phasing of fuel combustion in a multi-cylinder internal combustion engine - Google Patents
Method and apparatus for controlling phasing of fuel combustion in a multi-cylinder internal combustion engine Download PDFInfo
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- 239000000446 fuel Substances 0.000 title claims abstract description 86
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- 238000012544 monitoring process Methods 0.000 claims description 7
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- 230000009977 dual effect Effects 0.000 abstract description 2
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- 238000005259 measurement Methods 0.000 description 5
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000005094 computer simulation Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
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- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- WANLLPADDCXPGO-WMKJBNATSA-N (6r,9s,12s)-3-[(2s)-butan-2-yl]-6-[(4-methoxyphenyl)methyl]-9-[6-(oxiran-2-yl)-6-oxohexyl]-1,4,7,10-tetrazabicyclo[10.4.0]hexadecane-2,5,8,11-tetrone Chemical compound C([C@@H]1C(=O)NC(C(N2CCCC[C@H]2C(=O)N[C@@H](CCCCCC(=O)C2OC2)C(=O)N1)=O)[C@@H](C)CC)C1=CC=C(OC)C=C1 WANLLPADDCXPGO-WMKJBNATSA-N 0.000 description 1
- WANLLPADDCXPGO-UHFFFAOYSA-N Cyl-2 Natural products N1C(=O)C(CCCCCC(=O)C2OC2)NC(=O)C2CCCCN2C(=O)C(C(C)CC)NC(=O)C1CC1=CC=C(OC)C=C1 WANLLPADDCXPGO-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
- F02D35/028—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining the combustion timing or phasing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
- F02D35/023—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining the cylinder pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/008—Controlling each cylinder individually
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
- F02D2041/1413—Controller structures or design
- F02D2041/1418—Several control loops, either as alternatives or simultaneous
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
The invention relates to cylinder control combustion phasing in a multi-cylinder internal combustion piston engine (10) by means of a dual feedback control system, wherein an engine speed (20) and an engine load (22) are used as input values for a predefined combustion phasing map to determine a set-point. The set point is adjusted by a first feedback signal obtained by determining an exotherm timing at which a predetermined proportion of heat of the available combusted fuel is released and a second feedback signal obtained by determining (104) an average total exotherm rate (Q') in the cylinder.
Description
Technical Field
The present invention relates to a method of controlling the phasing of fuel combustion in a multi-cylinder internal combustion engine according to the preamble of claim 1.
The present invention relates to an apparatus for controlling combustion in a multi-cylinder internal combustion engine.
Background
The operating requirements of internal combustion piston engines are becoming increasingly demanding. For example, exhaust emission requirements of internal combustion piston engines are becoming more stringent. To cope with these demands, there are various technologies available by which gas emissions can be controlled when the engine is running. On the other hand, it is undesirable that the overall performance of the engine is affected by measures aimed at reducing emissions.
Publication WO2019034260A1 discloses a method in which the heat released by the combustion of fuel in the cylinders of an engine is used to control the amount of air involved in the combustion process in the cylinders of the engine.
The amount of air charged is itself an important factor in combustion, but for engine efficiency, control of combustion phasing is also critical. Combustion phasing means a range of crank angles (or piston positions) that control combustion of fuel introduced into a cylinder to occur. Traditionally, combustion phasing has been treated as a map-based fuel ignition timing controller, whether compression ignition or ignition by an external heat source.
However, optimal combustion phasing control must also take into account certain factors directly related to combustion occurring, such as cylinder pressure, rate of pressure rise, gas emissions, etc. It is also a common problem that all cylinders of the engine do not behave identically, for example the amount of air introduced into the combustion chamber may vary. In addition, the composition of the fuel combusted in an internal combustion piston engine may vary. This affects, for example, combustion stability and exhaust emissions.
Publication EP 3341603B 1 discloses a method for controlling the timing of combustion in at least one cylinder of an internal combustion engine using gaseous fuel, which first monitors the flywheel and uses an ignition map, and also uses the average exothermic timing to adjust the map-based control. According to the publication, the timing of the heat release relates to a certain point in time or crank angle position when at least 50% of the heat of the combustion fuel is released. The method further comprises the steps of: the pressure in at least one cylinder is monitored such that an average exotherm timing is inferred from the pressure monitoring. The ignition timing is controlled based on the average heat release timing.
Even though the disclosed method may be advantageous by itself, there is room for improving the accuracy of combustion control of individual cylinders of a multi-cylinder internal combustion engine.
It is an object of the present invention to provide a method and apparatus for controlling the phasing of fuel combustion in a multi-cylinder internal combustion engine, wherein the accuracy of the combustion control is significantly improved compared to prior art solutions.
Disclosure of Invention
The object of the invention is substantially met as disclosed in the independent claims and in other claims describing further details of different embodiments of the invention.
According to the present invention, a method of controlling phasing of fuel combustion in a multi-cylinder internal combustion engine, comprising a computer control system configured to control cylinder-by-cylinder phasing of fuel combustion (cylinder-WISE PHASING), the method comprising:
Monitoring engine speed and engine load, obtaining a set point for controlling phasing of combustion using the engine speed and engine load as input values to a predefined combustion phasing map providing a set point for controlling phasing of combustion common to all cylinders of the engine, and
Obtaining a first feedback value for each cylinder individually by determining an exothermic timing to release a predetermined proportion of heat of the available combustion fuel during one power stroke, and
A second feedback value for controlling the phasing of the combustion is obtained for each cylinder individually by:
Determining a cumulative heat release Q using a pressure value measured from a cylinder, the pressure value being a crank angle range over which fuel combustion occurs in one combustion cycle of an engine Caused by combustion of fuel therein, and
Determining an average total heat release rate Q 'resulting from combustion of the fuel by providing a linear fit to the cumulative heat release Q, the slope of which represents the average total heat release rate Q', and
Converting the average total heat release rate Q' to a second feedback signal having a second feedback value;
And
Combining the set point and the second feedback value to form a corrected set point for the computer control system of the engine for each cylinder individually, and
The correction set point and the first feedback value are combined to form a final set point for the computer control system of the engine for each cylinder individually.
By practicing the method according to the invention in a multi-cylinder piston engine, the overall performance of the engine is improved thanks to the precise cylinder control of the combustion timing. The method according to the invention solves the problems associated with irregularities in the fuel quality, air (oxygen) distribution between the engine cylinders and other cylinder fluctuations in the operation of the engine.
The term exothermic timing means the piston position at which a predetermined proportion of the heat of the available fuel in the combustion chamber of the cylinder after ignition is released, which may also be defined by the corresponding crank angle.
According to an embodiment of the present invention, the step of obtaining the second feedback value comprises: the average total heat release rate Q ' is compared with a nominal total heat release rate Qn ' value at the monitored engine load, and a second feedback value with respect to the nominal total heat release rate Qn ' is increased if the average total heat release rate Q ' is smaller than the nominal total heat release rate Qn ', and decreased if the average total heat release rate Q ' is larger than the nominal total heat release rate Qn '. The nominal total heat release rate Qn' value as a function of engine load may be stored in or available to the computer control system.
According to an embodiment of the present invention, the average total heat release rate Q 'is provided from fuel combustion by providing a least squares regression line for the accumulated heat release Q and defining a fit of the least squares regression line representing the average total heat release rate Q' to the slope of the accumulated heat release Q.
According to an embodiment of the invention, the method further comprises: a cylinder specific average total heat release rate Q 'value of successive combustion cycles in each cylinder of the engine is provided, and an average value of the cylinder specific average total heat release rate Q' values is calculated and used as the average total heat release rate.
According to an embodiment of the invention, in the method the pressure from each cylinder of the engine is measured substantially constantly or intermittently during combustion of fuel in the engine cylinder at a crank angle determined in the crank angle range.
According to an embodiment of the invention, a crank angle range in which fuel combustion occurs is usedThe pressure value measured from the cylinder determines the cumulative exotherm Q using the following equation:
According to an embodiment of the invention, the first feedback value is a crank angle value at which a predetermined proportion of the thermal RQ of the available combustion fuel Q fuel in the closed combustion chamber of the cylinder is released By using a crank angle range in which combustion of fuel occursThe pressure value measured from the cylinder is determined by using the following equation:
According to an embodiment of the invention, a crank angle value of a predetermined proportion of heat release of the available combustion fuel is determined during several power strokes, an average of the heat release timings is calculated, and the average is used to determine a first feedback value.
According to another embodiment of the invention, the predetermined proportion of the thermal RQ of the available combustion fuel is 15% to 50% of the thermal of the available combustion fuel Q fuel.
According to another embodiment of the invention, the predetermined proportion of the thermal RQ of the available combustion fuel is 15% to 25% of the thermal of the available combustion fuel Q fuel.
A computer readable memory device comprising instructions which, when executed by a computer, cause the computer to be configured to control a multi-cylinder internal combustion piston engine to perform a method according to the invention.
An apparatus for controlling combustion in a multi-cylinder internal combustion engine comprising a computer controller and means for monitoring engine speed, engine load and crank angle position and pressure in each cylinder of the engine, wherein the computer controller comprises:
A first control unit configured to determine a set point for controlling phasing of combustion using the engine speed and the engine load as input values of a predefined combustion phasing map,
A timing controller for determining a first feedback value for the computer control system for each cylinder individually by determining the exothermic timing of the heat release of a predetermined proportion of the available combustion fuel, and
-A second control unit configured to determine a second feedback value for controlling the phasing of the combustion for each cylinder individually by:
an heat release determination unit configured to determine a cumulative heat release Q using a pressure value measured from a cylinder in a crank angle range in which fuel combustion occurs in one combustion cycle of the engine, and
An heat release rate determining unit configured to determine an average total heat release rate Q 'by providing a linear fit to the accumulated heat release Q, a slope of which represents the average total heat release rate Q', and
A heat release rate controller configured to convert the average total heat release rate Q' into a feedback signal having a second feedback value,
And
A summing unit which determines correction set-points for the computer control system for the individual cylinders individually on the basis of the set-points and the second feedback values, and
-A combustion phasing control unit configured to provide a final set point for transmission to a charge ignition (charge ignition) actuator.
This allows the multi-cylinder piston engine to operate in a controlled manner and overall performance of the engine to be improved due to precise cylinder control of combustion timing. The apparatus according to the invention solves the problems associated with irregularities in the fuel quality, air (oxygen) distribution between the engine cylinders and other cylinder fluctuations in engine operation. This provides extremely accurate engine cylinder combustion control.
The invention provides dual feedback combustion phasing control. The exemplary embodiments of the invention presented in this patent application should not be interpreted as imposing limitations on the applicability of the appended claims. The verb "comprise" is used in this patent application as an open limitation that does not exclude the existence of unrecited features. The features recited in the dependent claims are freely combinable with each other unless explicitly stated otherwise.
Drawings
The invention will hereinafter be described with reference to the exemplary, schematic drawing figures in which
Fig. 1 shows an internal combustion multi-cylinder piston engine and an apparatus for controlling combustion in a multi-cylinder internal combustion engine according to an embodiment of the invention.
Fig. 2 shows an example of a cumulative heat release and an average total heat release rate according to an embodiment of the present invention.
FIG. 3 shows a trend graph of average total heat release rate according to an embodiment of the present invention.
Detailed Description
Fig. 1 schematically depicts a multi-cylinder internal combustion piston engine 10 and a computer control system 100 configured to control combustion processes in the engine 10, particularly cylinder-by-cylinder phasing of fuel combustion. The invention is particularly intended for phasing of fuel combustion in an engine having at least four cylinders, fig. 1 showing as an example the number of cylinders being four. Hereinafter, for simplicity, the internal combustion multi-cylinder piston engine 10 will be referred to as the engine 10. The engine 10 includes a number of cylinders 12, which may be arranged in an in-line configuration as shown or, for example, a V configuration. Each cylinder is provided with a fuel admittance means 14, which may be a direct injection means or a fuel admittance valve arranged to the intake passage of the cylinder, depending on the type of engine. The fuel admittance arrangement 14 includes a charge ignition actuator 16. A charge ignition actuator is a system that causes a charge in a cylinder to ignite in a controlled manner. Without intensive research into the various possibilities of igniting the fuel or charge in the combustion chamber of an engine, the actual implementation of a fuel ignition actuator depends on the operating principle of the engine. For example, the charge ignition actuator may be a fuel injection valve (compression ignition, auto-ignition), an external heat source (spark, plasma), or a combination thereof. The charge ignition actuator needs to be controllable by the computer control system 100. For example, in an engine using a gaseous fuel as its main fuel, the charge may be ignited by injecting a pilot fuel, the pilot fuel being ignited by compression ignition, and the ignition of the pilot fuel igniting the main fuel.
Each cylinder 12 of engine 10 is provided with a means for monitoring the pressure in each cylinder, such as a pressure sensor 18. The pressure sensor 18 is arranged to provide pressure measurement data to the computer control system 100. The engine is also provided with one or more crank angle sensors 20 or other suitable arrangement to act as a means for monitoring engine speed and/or providing crankshaft position information for use in the computer control system 100. The engine is further provided with a load detection device 22. The load is driving power generated by the engine to cope with an external drag power demand applied to the engine. For the case where the engine is operating at a constant speed, the load is equal and opposite to the external power demand. The load detection device may include a torque detector and utilize a crank angle sensor that also provides the rotational speed of the engine.
Typically, each measuring device or sensor is connected in data transmission with the computer control system 100, for example by a data bus or optical fiber or the like. The measurement data from each sensor may be used in the computer control system 100 to facilitate individual processing therein. The computer control system 100 includes a computer controller 102 and an executable computer program configured to control the combustion of fuel in the engine 10 to perform a method according to the present invention.
The computer controller 102 includes a first control unit 114 configured to determine settings for controlling phasing of combustion. The first control unit 114 is in data transfer communication with one or more crank angle sensors 20 and a load detection device 22. The first control unit uses the engine speed 20 and the engine load 22 as its feed or input values to obtain a global set point for timing the combustion phasing as an output signal of the first control unit 114. The first control unit 114 comprises a predefined combustion phasing map 114' which is stored in its memory or which is otherwise obtained by the first control unit. The combustion phasing map provides a global control value feed for all cylinders based on or as a function of the feed value. In other words, the control values and signals that ultimately control the charge ignition actuator 16 of a particular cylinder 12 are based on global control values generated by the first control unit 114 and corrected by the cylinder specific control unit.
To make the control more accurate, the computer controller includes a timing controller 116 configured to provide a first feedback value for the computer control system. The timing controller is configured to determine a timing of an exotherm (i.e., a crank angle value) of a predetermined proportion of heat release of the available combustion fuel during the power stroke. The timing controller 116 is in data transfer communication with the corresponding pressure sensor 18 that provides a feedback signal from the engine. A crank angle value at which a predetermined proportion of heat of the available combustion fuel is released is obtained using a pressure measurement from the cylinder. The timing controller may be provided with a reference pressure profile for the cylinder, and the measured cylinder pressure may be indicative of the monitored crank angle of the exothermic timing. The exothermic timing provided based on the measured pressure is compared to the nominal exothermic timing and a determination is made as to whether the exothermic timing is before or after the nominal exothermic timing. The ignition timing is retarded in the case where the heat release timing is before the nominal heat release timing, or advanced in the case where the heat release timing is after the nominal heat release timing.
Alternatively, the crank angle value at which a predetermined proportion of the thermal RQ of the available combustion fuel Q fuel is released may be obtained using the following equation using the pressure measured from the cylinder over the crank angle range from the start of combustion to the angle at which the predetermined proportion of the thermal RQ of the available combustion fuel is released
RQ is set using the measured pressure and as desired. Advantageously, the proportion of thermal RQ is 15-50%, preferably 15-25%.
The computer controller 102 also includes a combustion phasing control unit 112 configured to provide a final set point for the computer control system, which is communicated to the charge ignition actuator 16. The final set point is obtained by adjusting the correction set point provided by the summing unit 110.
To make the control more accurate, the computer controller includes means for generating a second feedback signal having a cylinder related control value for each cylinder 12 of the engine 10. For this purpose, the computer controller 12 comprises cylinder-specific second control units 103.1-103.N. This means that the computer controller 12 comprises a second control unit 103 for each cylinder 12 of the engine 10. The control unit 103 for each cylinder is in data transfer communication with a respective pressure sensor 18 and crank angle sensor 22 providing measurement signals from the engine.
Each second control unit 103 includes an exotherm determining unit 106.1-106.N configured and including an executable computer program to use pressure values measured from the cylinders to determine a crank angle range over which fuel combustion occurs in one combustion cycle of the engine 10The cumulative heat release Q resulting from the combustion of the fuel therein.
The heat release determination unit 106 for each cylinder is configured to operate as follows. The cumulative exotherm is determined based on pressure measurements 18 from cylinders of engine 10 and using crank angle measurements 20. The heat release is determined based on the pressure and known dimensions of the cylinder and the position of the piston (which may be derived from the actual crank angle position 28).
Heat release rate with respect to crank angle of internal combustion piston engineThe general formula of (2) is as follows
(1)
Wherein gamma is the heat capacity ratioP is the pressure, V is the volume of the cylinder, dV is the volume change in the cylinder,Is the crank angle variation, dp is the pressure variation in the cylinder. For clarity, it should be noted that the basic unit of heat release rate is J/crank angle.
Crank angle for fuel combustion to occur in a cylinder (herein, range) Integrating the heat release rate equation (1) to obtain the accumulated heat release Q, i.e
(2)
For clarity, it should be noted that the basic unit of cumulative exotherm is joule. This means in the crank angle rangeThe total heat released during combustion of fuel in the cylinder. The computer control system 100 reads or otherwise obtains the necessary information from the engine 10 to calculate the cumulative heat release Q Cyl1、QCyl2…QCyln for each cylinder 12 of the engine 10. In the crank angle rangeThe pressure is measured independently from each cylinder 12 of the engine during combustion of fuel in the cylinder 12 at the internally determined crank angle. The range represents the combustion phase in the cylinder; thus, a crank angle range in which fuel combustion occurs from one combustion cycle in one cylinder of the engineThe combustion of the fuel within determines the cumulative exotherm.
The computer controller 103 also includes heat release rate determination units 104.1-104.N configured and including a computer program executable to determine an average total heat release rate Q 'resulting from the combustion of the fuel by providing a linear fit to the cumulative heat release Q, the slope of the linear fit representing the average total heat release rate Q'.
More precisely, the heat release rate determination unit 104 for each cylinder is configured to operate as follows. The average total heat release rate of combustion Q' Cyl1、Q'Cyl2…Q'Cyln is determined from the cumulative heat release Q Cyl1、QCyl2…QCyln results. The average total heat release rate is obtained by providing a linear fit to the cumulative heat release Q, the slope of the linear fit representing the average total heat release rate Q'. An advantageous method of providing a linear fit is the least squares regression line method. An example of the cumulative heat release Q during one combustion cycle in a cylinder of an internal combustion piston engine is shown by a dashed line in fig. 3. The horizontal axis depicts crank angle position (degrees), where 0 degrees corresponds to top dead center of the piston in the cylinder. The vertical axis is exothermic (in kJ). The solid line Q 'depicts a linear fit to the cumulative heat release Q, the slope of the linear fit representing the average total heat release rate Q' of combustion. In the example of FIG. 3, the average total combustion rate is approximately 2.2 kJ/crank angle degrees.
The computer controller 103 also includes heat release rate controllers 108.1-108.N configured to convert the average total heat release rate Q' to a feedback signal having a second feedback value. The heat release rate controller 108 is advantageously configured to compare the average total heat release rate Q ' with a nominal total heat release rate Qn ' value at the monitored engine load, and with respect to the feedback value of the nominal total heat release rate Qn ', the second feedback value increases in case the average total heat release rate Q ' is smaller than the nominal total heat release rate Qn ', and decreases in case the average total heat release rate Q ' is larger than the nominal total heat release rate Qn '.
The computer controller further comprises a summing unit 110 wherein the set point provided by the first control unit 114 and the second feedback value provided by the second control unit 103 are combined to provide a corrected set point for the computer control system.
When the multi-cylinder internal combustion piston engine 10 is operated under the control of the computer control system 100, at least the following steps are performed in the method of controlling the phasing of fuel combustion. As a first measure of the method, the engine speed is measured by a crank angle/speed sensor 20, and the engine load is determined by a load detection device 22. These may be done using direct measurements of one or more variables of the engine and optionally using computer models or simulations. The monitored speed and load are utilized in the first control unit 114, which provides settings for controlling the phasing of the combustion. The first control unit and method utilize a predefined combustion phasing map, which is stored or available to the computer control system 100. The map provides control values based on the current speed and load of the engine for controlling the charge ignition actuator 16. The set point may be considered a global set point for combustion phasing of all cylinders of engine 10. Phasing is the timing of the combustion process with respect to the position of the piston in the cylinder. The set point from this method step is thus common to all cylinders of the engine.
The method further comprises the steps of: a first feedback value for the combustion phasing control unit 112 of the computer control system 100 is determined, which is the task of the timing controller 116. In step 1160, the pressure value 180 measured from the cylinder 12 is used to determine a crank angle value at which a predetermined proportion of the thermal RQ of the available combusted fuel is released, as described above in connection with the description of the timing controller 116. Thus, in method step 1120, the correction set point obtained from the summing unit 110 and the first feedback value obtained from step 1160 are converted into suitable control signals and values for controlling the cylinder-by-cylinder phasing of the combustion fuel.
The pressure in each cylinder is measured in order to obtain the actual pressure value in the cylinder in relation to the corresponding crank angle value (also representing the corresponding position of the piston in the cylinder). Crank angle measurements are advantageously provided because engine speed is the rate of change of the angular position of the crankshaft of the engine. The measured pressure of the engine and the corresponding crank angle are used to determine the cumulative heat release Q in the heat release determination unit 106. The cumulative heat release Q is determined using a pressure value measured from the cylinder, which is a crank angle range over which combustion of fuel occurs in one combustion cycle of the engine 10The combustion of the fuel therein.
Next, an average total heat release rate Q' C1、Q'C2…Q'Cn of combustion is determined from the cumulative heat release Q C1、QC2…QCn results for each cylinder in unit 104. This can be achieved by providing a linear fit to the cumulative heat release Q, the slope of the linear fit representing the average total heat release rate Q'. An advantageous method of providing a linear fit is the least squares regression line method. An example of the cumulative heat release Q during one combustion cycle in a cylinder of an internal combustion piston engine is shown by a dashed line in fig. 2. The horizontal axis depicts crank angle position (degrees), where 0 degrees corresponds to top dead center of the piston in the cylinder. The vertical axis is exothermic (in kJ). The solid line Q 'depicts a linear fit to the cumulative heat release Q, the slope of the linear fit representing the average total heat release rate Q' of combustion.
In the next step performed by unit 108, the obtained average total heat release rate Q' is converted into suitable control signals and values. This is advantageously achieved by comparing the average total heat release rate Q ' with a nominal total heat release rate Qn ' value at the monitored engine load, and with respect to a second feedback value of the nominal total heat release rate Qn ', the control value increases in case the average total heat release rate Q ' is smaller than the nominal total heat release rate Qn ', and decreases in case the average total heat release rate Q ' is larger than the nominal total heat release rate Qn '.
Next, the global set point obtained from unit 114 and the second feedback value obtained from unit 108 are combined or summed in unit 110, which results in a corrected set point for the combustion phasing control unit 112 along with the first feedback value.
The method may be implemented by a computer program stored in the readable memory means 101, which is executed by a computer controller of the multi-cylinder internal combustion piston engine.
FIG. 3 shows an exemplary trend graph of average total heat release rate over 200 consecutive engine cycles in one cylinder. It can be seen that there may be some variation in the combustion environment. Thus, according to an embodiment of the present invention, a cylinder specific average total heat release rate Q 'value for successive combustion cycles is provided from each cylinder 12 of the engine 10, and an average of the cylinder specific average total heat release rate Q' values is calculated for providing a second feedback value.
While the invention has been described herein by way of example in connection with what is presently considered to be the most preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment, but is intended to cover various combinations or modifications of its features and several other applications included within the scope of the invention as defined in the appended claims. When combinations are technically feasible, the details mentioned in connection with any of the embodiments above can be used in connection with another embodiment.
Claims (11)
1. A method of controlling phasing of fuel combustion in a multi-cylinder internal combustion engine (10), the multi-cylinder internal combustion engine (10) comprising a computer control system (100) configured to control cylinder-by-cylinder phasing of fuel combustion, the method comprising the steps of:
1.1. monitoring the speed of the engine (10) and the load of the engine (10),
1.2. Obtaining a set point (114) for controlling the phasing of the combustion by using the engine speed (20) and the engine load (22) as input values of a predefined combustion phasing map providing the set point for controlling the phasing of the combustion common to all the cylinders of the engine (10),
1.3. A first feedback value is obtained (116) for each cylinder individually by determining an exothermic timing to release a predetermined proportion of heat of the available combustion fuel during one power stroke,
Is characterized by comprising the following steps:
1.4. -obtaining (103) a second feedback value for controlling the phasing of the combustion for each cylinder individually by:
1.4.1. Determining (106) a cumulative heat release (Q) using a pressure value measured from the cylinder, the pressure value being caused by fuel combustion within a crank angle range (θ 1-θ2) in which fuel combustion occurs in one combustion cycle of the engine (10), and
1.4.2. Determining (104) an average total heat release rate (Q ') resulting from combustion of the fuel by providing a linear fit to the cumulative heat release (Q), the slope of the linear fit representing the average total heat release rate (Q'),
1.4.3. Converting (108) the average total heat release rate (Q') into a second feedback signal having the second feedback value,
And
1.5. Combining (110) the set point and the second feedback value to form a corrected set point for the computer control system (100) of the engine (10) for each cylinder (12) individually, and
1.6. The correction set point and the first feedback value are combined (112) to form a final set point for the computer control system (100) of the engine for each cylinder individually.
2. The method of controlling phasing of fuel combustion in a multi-cylinder internal combustion engine (10) of claim 1, wherein the step 1.4 further comprises:
-comparing (108) the average total heat release rate (Q ') with a nominal total heat release rate (Qn ') value at the monitored engine load, and-with respect to a second feedback value of the nominal total heat release rate (Qn '), the second feedback value increasing if the average total heat release rate (Q ') is smaller than the nominal total heat release rate (Qn '), and decreasing if the average total heat release rate (Q ') is larger than the nominal total heat release rate (Qn ').
3. The method of controlling fuel combustion in a multi-cylinder internal combustion engine (10) according to claim 1, characterized in that an average total heat release rate (Q ') is determined (104) from fuel combustion by providing a least squares regression line for the accumulated heat release (Q) and defining a fit of the least squares regression line representing the average total heat release rate (Q') to the slope of the accumulated heat release (Q).
4. The method of controlling fuel combustion in a multi-cylinder internal combustion engine (10) according to claim 1, characterized by providing a cylinder specific average total heat release rate (Q ') value for successive combustion cycles in each of the cylinders (12) of the engine (10) and calculating an average of the cylinder specific average total heat release rate (Q') values, and using the average in step 1.4.2 as set forth in claim 1.
5. The method of controlling combustion in a multi-cylinder internal combustion engine (10) according to claim 1, characterized in that the cumulative exotherm (Q) in step 1.4.1 is determined by using a pressure value measured from the cylinder in a crank angle range (θ 1-θ2) where fuel combustion occurs by using the following equation:
6. the method of controlling combustion in a multi-cylinder internal combustion engine (10) according to claim 1, characterized in that in said step 1.3, by using the pressure value measured from the cylinder in the crank angle range (θ 0-θRQ) where fuel combustion takes place, the crank angle θ RQ value at which a predetermined proportion of heat (RQ) of the available combustion fuel is released is determined by using the following equation:
7. The method of controlling combustion in a multi-cylinder internal combustion engine (10) according to claim 1, characterized in that in said step 1.3 a crank angle θ RQ value at which a predetermined proportion of heat (RQ) of available combustion fuel is released is determined by providing a reference pressure profile of the cylinders to the timing controller, wherein the measured pressure of the cylinders is indicative of the crank angle of the monitored heat release timing.
8. The method of controlling combustion in a multi-cylinder internal combustion engine (10) according to claim 1, 6 or 7, characterized in that in said step 1.3 a crank angle value is determined during several power strokes at which a predetermined proportion of the heat of the available combustion fuel is released, an average value of said heat release timings is calculated, and said average value is used to determine said first feedback value.
9. The method of controlling combustion in a multi-cylinder internal combustion engine (10) according to claim 1, 6, 7 or 8, characterized in that a crank angle value is used where 15% to 50% of the heat of the available combustion fuel during one power stroke is released.
10. A computer readable memory device (101) comprising instructions which, when executed by a computer, cause the computer to be configured to control a multi-cylinder internal combustion piston engine (10) to perform the method according to any one of claims 1 to 9.
11. An apparatus for controlling combustion in a multi-cylinder internal combustion engine (10) having a computer controller and means for monitoring engine speed (20), engine load (22) and crank angle position (20) and pressure (18) in each cylinder (12) of the engine (10), the computer controller (100) comprising:
a first control unit (114) configured to determine a set point for controlling the phasing of the combustion by using the engine speed and the engine load as input values to a predefined combustion phasing map,
-A timing controller (116) for determining a first feedback value for the computer control system (100) for each cylinder (12) individually by determining an exothermic timing at which a predetermined proportion of the heat of the available combustion fuel is released, and
-A second control unit (103) configured to determine, for each cylinder, individually, a second feedback value for controlling the phasing of the combustion by:
An heat release determination unit (106.1-106. N) configured to determine a cumulative heat release (Q) by using a pressure value measured from the cylinder in a crank angle range (θ 0-θ1) in which fuel combustion occurs in one combustion cycle of the engine (10), and
An heat release rate determination unit (104.1-104. N) configured to determine an average total heat release rate (Q ') by providing a linear fit to the accumulated heat release (Q), a slope of the linear fit representing the average total heat release rate (Q'),
A heat release rate controller (108.1-108. N) configured to convert the average total heat release rate (Q') into a feedback signal having the second feedback value,
And
-A summing unit (110) for determining correction set-points for the computer control system (100) for the respective cylinders individually based on the set-points and the second feedback value, and
-A combustion phasing control unit (112) configured to provide a final set point for transmission to the charge ignition actuator (16).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2021/087041 WO2023117060A1 (en) | 2021-12-21 | 2021-12-21 | Method of and apparatus for controlling phasing of combustion of fuel in a multi-cylinder internal combustion engine |
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| CN118434962A true CN118434962A (en) | 2024-08-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180105219.6A Pending CN118434962A (en) | 2021-12-21 | 2021-12-21 | Method and apparatus for controlling phasing of fuel combustion in a multi-cylinder internal combustion engine |
Country Status (3)
| Country | Link |
|---|---|
| KR (1) | KR20240105448A (en) |
| CN (1) | CN118434962A (en) |
| WO (1) | WO2023117060A1 (en) |
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| FR2907509A1 (en) * | 2006-10-19 | 2008-04-25 | Peugeot Citroen Automobiles Sa | Characteristic parameter e.g. mass of air, estimating method for e.g. diesel engine, involves controlling thermal flux applied to component e.g. piston, of engine in closed loop, from derived magnitude of estimated characteristic parameters |
| JP6213532B2 (en) * | 2015-08-04 | 2017-10-18 | トヨタ自動車株式会社 | Control device for internal combustion engine |
| CN107923327B (en) | 2015-08-24 | 2020-11-06 | 瓦锡兰芬兰有限公司 | Method and device for controlling an internal combustion engine |
| CN111051670B (en) | 2017-08-18 | 2022-03-29 | 瓦锡兰芬兰有限公司 | Method for controlling fuel combustion in a multi-cylinder internal combustion engine and computer control system configured to control the combustion process in a multi-cylinder internal combustion piston engine |
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- 2021-12-21 CN CN202180105219.6A patent/CN118434962A/en active Pending
- 2021-12-21 KR KR1020247019813A patent/KR20240105448A/en unknown
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| KR20240105448A (en) | 2024-07-05 |
| WO2023117060A1 (en) | 2023-06-29 |
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