DE102015210745A1 - SYSTEM AND METHOD FOR PREDICTING THE TIME OF COMBUSTION IN A MOTOR WITH A HOMOGENEOUS COMPRESSION IGNITION - Google Patents

Abstract

One system predicts the time of combustion (CA50) for an operating stroke of an HCCI engine by an Arrhenius equation, in which at least two combustion reaction parameters from combustion reaction parameters representing pressure state variable cylinder pressure inside the cylinder (Pcyl_10BTDC) as fuel mass fraction (equivalence ratio). φ) and as a state variable of the burnt gas comprise a residual gas content (Xrg) are included.

Description

TECHNICAL AREA

The present invention relates to a system and method for predicting the timing of combustion for a power stroke in a cylinder of a homogeneous compression ignition engine.

GENERAL PRIOR ART

In recent years, Homogeneous Charge Combustion Ignition (HCCI) internal combustion engines have been proposed which employ combustion as a form of combustion caused by auto-ignition of an air-fuel mixture by introducing high-temperature burnt gas into one Cylinder is triggered. This form of combustion, which is triggered by homogeneous compression ignition and referred to as homogeneous compression ignition (HCCI) combustion, has attracted attention as a form of combustion for gasoline and diesel engines.

HCCI combustion is initiated by auto-ignition without any help from a spark, autoignition being achieved by an increase in temperature and pressure of an air-fuel mixture in a cylinder caused by compression of the mixture. This HCCI combustion, in which combustion of a majority takes place simultaneously from multiple ignition points in the mixture in the cylinder, has the advantage that a higher thermal efficiency is obtained with a short burning time.

For example, when HCCI combustion is used in gasoline engines, it will allow engine manufacturers to expect, above all, an improvement in fuel consumption. In addition, when using HCCI combustion in diesel engines, engine manufacturers will most likely expect a reduction in soot and nitrogen oxide emissions.

The time of auto-ignition in an HCCI internal combustion engine employing HCCI combustion differs depending on various kinds of state variables of a charge of the mixture in a cylinder including the temperature of the charge in the cylinder, the pressure of the charge in the cylinder Amount of air in the charge in the cylinder, the amount of residual gas in the charge in the cylinder, the amount of fuel in the charge in the cylinder, and the like considerably. This poses a problem in that the engine may knock or misfire unless the timing of the autoignition is properly controlled because the charge may not burn at the appropriate time. Therefore, there is a need to predict the timing of combustion of the charge, which is triggered by auto-ignition, with good accuracy.

The prior art includes HCCI internal combustion engines that predict the timing of combustion of the air-fuel mixture triggered by auto-ignition during the HCCI combustion mode, as in FIG JP 2009-168027 A (also as US 2009/0182485 A1 and DE 10 2008 004 361 A1 released), JP 2006-2637 A , and JP 2008-101591 A which are listed below as Patent Literature Examples 1 to 3.

The in JP 2009-168027 A The HCCI engine described above predicts the mass fraction of combustion of 50% in one cycle by an equation containing the predicted mass fraction of combustion of 50% based on the manipulated variables in terms of residual gas retention and / or air supply introduced into the engine in the cycle, the amount of fuel injected in the previous cycle, the induced mean pressure determined for the previous cycle, the mass fraction of combustion of 50% determined for the previous cycle or duty cycle and gives parameters.

The HCCI combustion engine used in JP 2006-2637 A predicts the ignition delay using the Arrhenius equation, which predicts the ignition delay based on parameters related to the pressure of a charge of an air-fuel mixture, the temperature of the charge and the air-fuel ratio of the mixture and the like are determined.

The HCCI combustion engine used in JP 2008-101591 A is described predicts the ignition delay using the Arrhenius equation, which gives the predicted ignition delay based on the pressure of a charge of the mixture in a cylinder, the activation energy, the absolute temperature of the charge in the cylinder, the gas constant, and various constants.

STATE OF THE ART

Patent Literature

• Patent Literature Example 1 JP 2009-168027 A
• Patent Literature Example 2: JP 2006-2637 A
• Patent Literature Example 3: JP 2008-101591 A

BRIEF SUMMARY OF THE INVENTION

TECHNICAL PROBLEM

However, the autoignition timing or timing of combustion in HCCI combustion is governed by the influence of a physical factor such as the temperature distribution due to a turbulent mixture and the heat loss through the cylinder wall on the ignition delay time caused by chemical reactions such as a low-temperature oxidation reaction and high-temperature oxidation reaction - is determined, mastered. Moreover, the chemical reaction rate in HCCI combustion is significantly affected not only by the cylinder, but also, for example, by the equivalence ratio and the residual gas content.

However, in the HCCI internal combustion engines described in the above Patent Literature Examples 1 to 3, the above-described physical factor and factors which greatly affect the chemical reaction rate become the predictions of the autoignition timing or the combustion timing in the HCCI combustion not considered. Therefore, for the HCCI internal combustion engines described in the above-mentioned patent literature examples, it can be said that the prediction accuracy for the autoignition timing or the timing of combustion in the HCCI combustion is not necessarily high.

Accordingly, it is an object of the present invention to provide a system and method for predicting the timing of combustion in an HCCI internal combustion engine, thereby improving the prediction accuracy for the autoignition timing or timing of combustion in HCCI combustion over the prior art ,

THE SOLUTION OF THE PROBLEM

According to the first aspect of the present invention, there is provided a system or method for predicting the timing of combustion of a mixture within a cylinder for a stroke of an HCCI internal combustion engine, comprising: determining at least two combustion reaction parameters from combustion reaction parameters representing a pressure state variable; which is determined based on a cylinder pressure inside the cylinder, a mass of fuel mass determined based on the state of the fuel mass and the air mass inside the cylinder, and a state variable of the burnt gas based on the retention of the burnt gas inside the cylinder is determined; Taking the determined two combustion reaction parameters into an Arrhenius equation; and predicting the timing of combustion for the power stroke using the Arrhenius equation.

According to the second aspect of the present invention, it is preferable that an exponent of each of the specific two combustion reaction parameters is a predetermined number.

According to the third aspect of the present invention, there is provided a system or method for predicting a combustion timing of a mixture inside a cylinder for a power stroke of an HCCI internal combustion engine, comprising: determining at least one combustion reaction parameter from combustion reaction parameters including a pressure state variable is determined based on a cylinder pressure inside the cylinder, a mass fraction of fuel determined based on the state of the fuel mass and the air mass inside the cylinder, and a state variable of the burnt gas based on the retention of the burnt gas inside the cylinder is determined; Determining at least one fuel condition parameter from fuel condition parameters including a mixed prediction variable for predicting the mixed state of the fuel inside the cylinder, an injection completion timing at which fuel injection is completed, and a heat loss prediction variable for predicting heat loss due to heat transfer between a wall surface and the fuel Inside the cylinder include; Taking the determined combustion reaction and fuel condition parameters into an Arrhenius equation; and predicting the timing of combustion for the power stroke using the Arrhenius equation.

According to the fourth aspect of the present invention, it is preferable that an exponent of each of the determined combustion reaction and fuel condition parameters is a predetermined number.

According to the fifth aspect of the present invention, it is preferable that the fuel mass fraction is an equivalence ratio or an inverse of the equivalence ratio.

According to the sixth aspect of the present invention, it is preferable that the status variable of the combusted gas is a percentage of the mass of the residual gas with respect to the mass of the mixture in the cylinder.

According to the seventh aspect of the present invention, it is preferable that the mixed prediction variable is an engine speed of the engine or a reciprocal of the engine speed.

According to the eighth aspect of the present invention, it is preferable that the heat loss prediction variable is a difference between an exhaust gas temperature and an intake temperature.

TECHNICAL EFFECTS OF THE INVENTION

According to the first aspect, it is possible to predict the timing of combustion more accurately than in the conventional art, since arithmetic operations are performed using an Arrhenius equation to predict the timing of the combustion taking combustion reaction parameters that influence a change in the timing of combustion can, in the equation. In addition, according to the first aspect, it is possible to predict the timing of combustion even if a change in the operating state of the HCCI engine occurs because arithmetic operations are performed using the Arrhenius equation by including at least two such combustion reaction parameters in the equation.

Accordingly, the first aspect makes it possible to improve the prediction accuracy for the time of combustion in an HCCI engine over the prior art.

According to the second aspect, since an exponent of each of the combustion reaction parameters is a predetermined number, it is possible to more accurately predict the timing of the combustion. For example, when the exponents added to the respective combustion reaction parameters are determined experimentally in advance, it is possible to predict the timing of combustion with high accuracy by absorbing individual differences derived from specifications of HCCI internal combustion engines.

According to the third aspect, since arithmetic operations are performed using an Arrhenius equation to predict the timing of combustion taking combustion reaction and fuel condition parameters, which is a change in timing, it is possible to predict the timing of combustion more accurately than in the conventional art can affect combustion in the equation. Accordingly, the third aspect makes it possible to improve the prediction accuracy for the time of combustion in an HCCI engine over the prior art.

According to the fourth aspect, since an exponent of each of the combustion reaction and fuel condition parameters is a predetermined number, it is possible to more accurately predict the timing of the combustion. For example, when the exponents added to the respective combustion reaction and fuel condition parameters are determined experimentally in advance, it is possible to predict the timing of combustion with high accuracy by absorbing individual differences derived from specifications of HCCI internal combustion engines ,

According to the fifth aspect, since a fuel equivalent ratio, which is a ratio between the stoichiometric air-fuel ratio and an actual air-fuel ratio, or an inverse of the equivalence ratio indicating an excess air ratio, is used as the fuel mass fraction, it is possible to to improve the prediction accuracy for the time of combustion in the HCCI combustion over the prior art, in which arithmetic operations of the Arrhenius equation are performed by measuring only the actual air-fuel ratio.

In the sixth aspect, the ratio of the residual gas retention with respect to the cylinder charge is used as the status variable of the burned gas. The residual gas contains nitrogen oxides and partially oxidized fuel, which is why the thermodynamic properties such as the heat capacity ratio and the temperature differ from those of the fresh or intake air. Thus, the amount of the residual gas may cause a temperature rise and a change in the chemical properties of the combustion inside the cylinder, thereby affecting the timing of the combustion. Therefore, the sixth aspect makes it possible to more accurately predict the timing of combustion because arithmetic operations of the Arrhenius equation are performed using the ratio of the residual gas retention to the cylinder charge.

In the seventh aspect, the engine speed or a reciprocal of the engine speed is used as the mixed prediction variable. It is known that the mixed state of the fuel affects the combustion speed and the Degree of mixing varies depending on the engine speed. Therefore, the seventh aspect makes it possible to improve the prediction accuracy of the timing of combustion because arithmetic operations of the Arrhenius equation are performed using the engine speed or its reciprocal to predict the mixing state of the fuel.

In the eighth aspect, a difference between the exhaust gas temperature and the intake temperature is used as the heat loss prediction variable. It is noted that the difference between the exhaust gas temperature and the intake temperature has a correlation with the distribution of the gas temperature inside the cylinder. It is also known that the distribution of gas temperature generated inside the cylinder affects the timing of combustion. Therefore, the eighth aspect makes it possible to improve the prediction accuracy because arithmetic operations of the Arrhenius equation are performed using the difference between the exhaust gas temperature and the intake temperature to account for the influence of the gas temperature distribution generated inside the cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

1 FIG. 15 is a structural diagram schematically illustrating a vehicle including a combustion timing prediction system according to a first embodiment of the present invention. FIG.

2 Fig. 10 is a block diagram schematically illustrating the combustion timing prediction control according to the first embodiment of the present invention.

3 FIG. 10 is a flowchart illustrating a processing procedure executed by an ECU for the timing of combustion and the ignition timing control according to the first embodiment of the present invention. FIG.

4 FIG. 15 are views for comparing the accuracy of predicting the timing of combustion with a conventional technology, wherein (a) represents the accuracy of predicting the timing of combustion by the combustion timing prediction system according to the first embodiment of the present invention, and FIG (b) represents the accuracy of predicting the timing of combustion by a combustion timing prediction system according to the conventional technology.

5 FIG. 10 is a flowchart illustrating a processing procedure executed by an ECU for the timing of combustion and the ignition timing control according to a second embodiment of the present invention. FIG.

6 FIG. 10 is a flowchart illustrating a processing procedure executed by an ECU for the timing of combustion and the ignition timing control according to a third embodiment of the present invention. FIG.

DESCRIPTION OF EMBODIMENTS

With reference to 1 to 6 Hereinafter, embodiments of the present invention will be described.

First embodiment

With reference to 1 includes a vehicle 1 to which the present invention is assigned, a motor 2 , an intake system 3 , an exhaust system 4 , an EGR system 5 and an ECU 10 , which works as a system for predicting the timing of combustion.

The motor 2 For example, but not limited to, includes a four-cylinder in-line gasoline engine. At the engine 2 it may be a so-called gasoline direct injection engine having an injector configured to inject fuel directly into a combustion chamber. The number of cylinders is not limited to four. The motor 2 is not limited to a gasoline engine, but may be a diesel engine.

Moreover, the engine to which the present invention is assigned is a homogeneous compression ignition internal combustion engine that permits homogeneous compression ignition combustion (referred to as "HCCI combustion"), ie, combustion caused by auto-ignition of an air-fuel mixture by compressing the air-fuel mixture in a cylinder 21 without one through a spark plug 20 generated sparks is triggered.

Moreover, the engine is 2 engineered to produce a spark ignition (SI) combustion by forcibly igniting the air-fuel mixture with a spark plug 20 generated sparks allows. Thus, the engine allows 2 switching between HCCI combustion and SI combustion in response to engine operating conditions determined by engine speed and load.

The intake system 3 is with a suction passage 3a executed. The intake passage 3a is with a mechanical loader 30 and a charge air cooler 31 Mistake. The mechanical loader 30 is a mechanically driven supercharger and compresses the intake air to charge the engine by jointly rotating two rotors in its housing. The mechanical loader 30 uses the engine as its power source 2 ,

The intercooler 31 is with respect to the direction in which the intake air flows, so on the downstream side of the mechanical supercharger 30 arranged that he sucked the intake air through the mechanical loader 30 was compressed, cools. This increases the filling degree of the engine, thereby improving the suction efficiency.

The exhaust system 4 is with an exhaust passage 4a executed. The exhaust passage 4a is with a catalyst 40 Mistake. The catalyst 40 clean that from the engine 2 discharged exhaust gas.

The EGR system 5 includes an EGR pipe 50 that with an EGR passage 50a is executed, and an EGR valve 51 , The EGR passage 50a provides a connection between the exhaust passage 4a and the suction passage 3a ready to take a part of the exhaust gas passing through the exhaust passage 4a runs, attributed.

The EGR valve 51 is in the EGR passage in such a way 50a incorporated that there is an EGR amount, which is the amount of exhaust gas that goes to the intake passage 3a is to be traced, indicates, regulates. Opening / closing the EGR valve 51 is through the ECU 10 controlled.

The ECU 10 comprises a microcomputer with, for example, a CPU, a RAM, a ROM, an input / output interface and the like, wherein the CPU performs signal processing according to programs stored in advance in the ROM using a temporary storage function of the RAM , In the ROM, various control parameters, various characteristics and the like are stored in advance.

In addition, the input terminals of the ECU 10 various sensors such as an air flow sensor 101 , an intake temperature sensor 102 , a suction pressure sensor 103 , a suction O ₂ sensor 104 , a cylinder pressure sensor 105 , an exhaust temperature sensor 106 , an air / fuel sensor (A / F sensor) 107 , a crank angle sensor 180 and a coolant temperature sensor 181 connected.

The airflow sensor 101 is in such a way in that part of the intake passage 3a which is at the upstream side of the mechanical supercharger with respect to the direction in which the intake air flows 30 located, that it detects the intake air quantity. The intake temperature sensor 102 is in such a way in that part of the intake passage 3a , which is in relation to the direction in which the intake air flows, on the downstream side of the intercooler 31 is installed so as to detect an intake air temperature indicating the temperature of the intake air (hereinafter simply referred to as "intake temperature").

The suction pressure sensor 103 is in such a way in that part of the intake passage 3a , which is in relation to the direction in which the intake air flows, on the downstream side of the intercooler 31 is installed, that it detects an intake air pressure, which indicates the pressure of the intake air. The intake O ₂ sensor 104 is in such a way in that part of the intake passage 3a , which is in relation to the direction in which the intake air flows, on the downstream side of the intercooler 31 is located, that he has the oxygen concentration of the gas in a cylinder 21 is admitted.

The cylinder pressure sensor 105 is in a cylinder head, not shown, with the cylinder 21 is designed to have a cylinder internal pressure, which is a pressure in the cylinder 21 indicates capture. The exhaust gas temperature sensor 106 is in such a way in that part of the exhaust passage 4a which is in relation to the direction in which the exhaust gas flows, on the upstream side of the catalyst 40 is installed to detect an exhaust gas temperature indicative of the temperature of the exhaust gas (hereinafter simply referred to as "exhaust gas temperature").

The air / fuel sensor 107 is in that part of the exhaust passage 4a which is in relation to the direction in which the exhaust gas flows, on the upstream side of the catalyst 40 is installed and provides linear characteristics proportional to actual values of the exhaust gas air-fuel ratio. The air / fuel sensor 107 detects actual values of the exhaust gas air-fuel ratio based on the oxygen concentration in the exhaust gas.

The crank angle sensor 180 is in the engine 2 Installed to a crank angle of the crankshaft of the engine 2 capture. The coolant temperature sensor 181 is in the engine 2 installed to the temperature of the coolant for the engine 2 , ie, to detect the coolant temperature.

There are also various pieces of equipment such as the EGR valve 51 . spark 20 and injectors 23 to the output terminals of the ECU 10 connected. The ECU 10 controls these various pieces of equipment based on the input values of the various sensors previously described.

The ECU 10 is configured to perform, for example, control of the prediction of the combustion timing, the timing of combustion in the HCCI internal combustion engine 2 predict. Moreover, the ECU 10 adapted to be based on the timing of the combustion, which was predicted by the control for the prediction of the combustion timing, a control of the ignition timing for controlling an injector 23 and a spark plug 20 to allow for HCCI combustion at a convenient time.

Now referring to 2 For example, the control for predicting the combustion timing and the control of the ignition timing performed by the ECU 10 be executed described.

As in 2 shown calculates the ECU 10 on the basis of the detection result obtained from the crank angle sensor 180 is entered, the engine speed Ne. Moreover, the ECU calculates 10 based on the accelerator pedal position input from an accelerator pedal position sensor, the engine load.

The ECU 10 calculated based on the engine speed Ne, the engine load and the air flow sensor 101 detected intake air amount a basic fuel injection amount. Moreover, the ECU calculates 10 On the basis of the basic fuel injection quantity and the intake air amount, the equivalence ratio φ (the Greek letter phi), which is the ratio of the air-fuel ratio of the engine 2 embedded mixture is defined to the stoichiometric air-fuel ratio.

The ECU 10 calculated from the equivalence ratio based on the amount of intake air passing through the intake O ₂ sensor 104 detected oxygen concentration and the actual air-fuel ratio by the air / fuel sensor 107 A certain amount of EGR gas is determined by the EGR system 5 to the engine intake side (hereinafter referred to as "external EGR gas").

It should be noted that the ratio of oxygen (O ₂ ), nitrogen (N ₂ ) and carbon dioxide (CO ₂ ) in the air is well known since these are the main gases of the air. For this reason, the oxygen concentration of the intake air amount passing through the air flow sensor 101 is detected, well known. Thus, the ECU 10 the external EGR quantity with the intake O ₂ sensor 104 by detecting the oxygen concentration in the amount of intake air containing exhaust gas, its oxygen concentration by the air / fuel sensor 107 is determined.

The ECU 10 calculated using the equation of state for the gas based on the cylinder pressure and the exhaust gas temperature during the opening of an intake valve by the cylinder pressure sensor 105 and the exhaust gas temperature sensor 106 are detected, and the volume of a combustion chamber when the cylinder pressure and the exhaust gas temperature are detected, the mass of the residual gas as the amount of the residual gas. The equation of state for the gas is expressed as "PV = mRT", where "P" is the cylinder pressure, "V" is the volume of a combustion chamber, "m" is the mass of the residual gas, "R" is the gas constant of the residual gas, and "T" is the exhaust gas temperature that coincides approximately with the cylinder temperature.

The ECU 10 calculates the residual gas retention in a cylinder X _rg based on the amount of external EGR gas and the amount of residual gas. In particular, the ECU calculates 10 the residual gas retention X _rg , which is the ratio of the residual gas amount to the mixture amount in the cylinder, which is the total of the external residual gas amount, the residual gas amount, the intake air amount, and the basic _{fuel injection} amount.

The ECU 10 Based on the amount of external EGR gas, the intake air amount, the base _{fuel injection amount} , the residual gas amount and the cylinder pressure, the cylinder pressure P _{cyl_10BTDC} , where "cyl" indicates something in a cylinder, and 10BTDC calculates the timing at a crankshaft angle of 10 ° before the upper one Indicates the dead center of the compression.

In particular, the ECU calculates 10 the cylinder pressure P _{cyl_10BTDC} when the cylinder pressure is detected by the cylinder _{pressure sensor} as mentioned below. Assuming a polytrophic process, the ECU calculates 10 the cylinder pressure P _{cyl_10BTDC} based on the following equation (1) using the cylinder pressure P _{cyl_ivc} and the volume of the combustion chamber V _{cyl_ivc} when closing the intake valve and the volume V _{cyl_10BTDC} at 10 ° before compression top dead center, where "ivc" is the instant indicating the closing of the intake valve. In addition, "n" indicates the polytropic index in the following equation. P _{cyl_10BTDC} = P _{cyl_ivc} (V _{cyl_ivc} / V _{cyl_10BTDC} ) ⁿ (1)

Moreover, the ECU 10 as in the above-mentioned calculation of the cylinder pressure P _{cyl_10BTDC} using the following equation (2), calculate the cylinder _temperature T _{cyl_10BTDC} . T _{cyl_10BTDC} = T _{cyl_ivc} (V _{cyl_ivc} / V _{cyl_10BTDC} ) ^n-1 (2)

The ECU 10 For example, the cylinder _temperature T _{cyl_ivc} in the above-mentioned equation (2) after determining the cylinder pressure P _{cyl_ivc} when closing the intake valve, the volume of a combustion chamber V _{cyl_ivc} when closing the intake valve, the mass of the cylinder mixture _{charge of} a mixture m, and the gas constant R of the mixture from the equation of state for the gas, ie, find out "P _{cyl_ivc} V _{cyl_ivc} = mRT".

After determining the average molecular weight of the mixture of the molar proportions of the component of the external gas, the component of the residual gas, the component of the intake air, the component of the fuel, and the other components, the gas constant of the mixture by dividing the universal gas constant R, ie , R = 8.3144621 (75) JK ^-1 mol ^-1 , obtained by the average molecular mass of the mixture.

Moreover, the ECU 10 the cylinder pressure P _{cyl_ivc} and the cylinder _temperature T _{cyl_ivc} given above, when the cylinder _{pressure sensor} 105 is not used, by calculations using each of the following equations. P _{cyl_ivc} = I * M _air ^J * P _{in_ivc} ^K (3) T _{cyl_ivc} = L * T _{in_ivo} + N * T _{ex_ivo} + Q * T _water (4)

In the above equation (3), M _{air is} the intake air amount, that is, the air flow sensor 101 detected mass air _flow , and P _{in_ivc is} the intake air _pressure when closing the intake valve. In the above equation (4), T _{in_ivo is} the cylinder temperature when closing the intake valve, T _{ex_ivo} , the exhaust gas temperature when closing the intake valve, and T is the _water through the coolant temperature sensor 181 detected coolant temperature.

Moreover, the values of the indices J and K in the above equation (3) are determined by a multivariate regression analysis of data in advance considering individual differences resulting from the specifications of the engine 2 were determined experimentally. Moreover, similarly to the above indices J and K, the values of the indices I, L, N and Q in the above equations (3) and (4) are determined by a multivariate regression analysis of data which is preliminarily calculated taking into account individual differences the specifications of the engine 2 were determined experimentally.

Moreover, the ECU says 10 the time of combustion CA50 in the engine 2 by using the Arrhenius equation, assuming a combustion reaction parameter (of combustion reaction parameters) and a fuel condition parameter (of fuel condition parameters) as their pre-exponential factor. According to the present embodiment, a crank angle (CA) at a mass fraction of combustion of 50% is treated as a time of combustion CA50.

The timing of combustion in an HCCI internal combustion engine such as the engine 2 is governed by the influence of a physical factor such as the temperature distribution due to a turbulent mixture and the heat loss through the cylinder wall to the ignition delay time, which is speed-determined by chemical reactions such as a low-temperature oxidation reaction and a high-temperature oxidation reaction. Accordingly, for accurate prediction of the timing of combustion, there is a need to consider the physical factor and factors that influence the rate of chemical reaction.

Therefore, in order to improve the accuracy of predicting the timing of combustion, the present embodiment has the combustion reaction parameter (s) and the fuel condition parameter (s) as the pre-exponential factor in the Arrhenius equation, which is a formula for the temperature dependence of reaction rates. added.

These combustion reaction _{parameters are} the cylinder pressure P _{cyl_10BTDC} determined by the equation (1) as a pressure state variable based on the cylinder pressure, the residual gas _content X _rg , which is a variable regarding the burnt gas based on the retention of the burnt gas inside of the cylinder 21 and the equivalence ratio φ determined based on the basic fuel injection amount and the intake air amount. The equivalence ratio φ corresponds to a mass fraction of fuel based on the state of the fuel mass and the air mass inside the cylinder 21 is determined. The mass fraction may be a reciprocal of the equivalence ratio φ, which indicates a factor of excess air.

These fuel condition parameters are a reciprocal of the engine speed Ne, which is a mixed prediction variable for predicting the mixed state of the fuel in the engine Inside of the cylinder 21 represents a time EoI of completion of the injection, a difference (T _ex - T _in ) between the exhaust gas temperature T _ex and the intake temperature T _in which a heat loss prediction variable for predicting the heat transfer between a wall surface and the fuel inside the cylinder 21 represents heat loss caused. It should be noted that the mixed prediction variable may be represented by the engine speed Ne.

In particular, the ECU determines 10 the time of combustion CA50 by calculating the following equation (5) based on each of the combustion reaction parameters and each of the fuel _{condition parameters set forth} above and the cylinder _temperature T _{cyl_10BTDC calculated} by the aforementioned Equation (2). CA50 = A · P _{cyl_10BTDC} ^B · φ ^C · X _rg ^D · (1 / Ne) ^F · (T _ex - T _in ) ^G · EoI · ^H · exp (-E / RT _{cyl_10BTDC} ) (5)

Here, in equation (5), R is the gas constant of the mixture, and A is the index determined by a multivariate regression analysis of data which, considering individual differences, from the specifications of the engine 2 were determined experimentally.

In the equation (5), an exponent of each of the combustion reaction parameters is a predetermined number B or C or D, and an exponent of each of the fuel condition parameters is a predetermined number F or G or H. These exponents B, C, D and F, G , H are as the exponent A numbers, which are determined by a multivariate regression analysis of data, which in advance, taking into account individual differences arising from the specifications of the engine 2 were determined experimentally.

Moreover, the ECU compares 10 the combustion time CA50 determined by the equation (5) with the target combustion timing obtained from a target combustion timing characteristic, and determines the fuel injection amount, the fuel injection timing, the ignition timing, and the number of times of ignition based on this comparison result. The target ignition timing characteristic is a characteristic used to determine a target ignition timing using, e.g. B., the engine speed Ne is designed as a parameter and in the ROM of the ECU 10 was stored after the relationship between the engine speed Ne and the time of combustion was determined experimentally.

The target combustion timing is expressed by the crank angle and represents a target crank angle at which a mass fraction of combustion of 50% is present. Thus, a target value of the crank angle CA50 will be treated below as the target combustion time CA50.

In particular, the ECU determines 10 the fuel injection amount, the fuel injection timing, the ignition timing, and the number of times of ignition depending on whether the timing of the combustion CA50 coincides with the target ignition timing CA50 or not. The case where the timing of the combustion CA50 coincides with the target combustion timing CA50 includes the case where the timing of the combustion CA50 exactly coincides with the target combustion timing CA50 and that in which the timing of the combustion CA50 falls within a predetermined tolerance range of the target combustion timing CA50 drops. The predetermined tolerance range will depend on the specification of the motor 2 is arbitrarily set, for example ± 1 ° CA.

For example, if the combustion time CA50 coincides with the target combustion time CA50, the ECU controls 10 along with the fuel injection amount, the fuel injection timing, the ignition timing, and the number of times of ignition determined from a fuel injection quantity characteristic, a fuel injection timing, an ignition timing, and the number of times of ignition, the operation of the injector 23 and the spark plug 20 to perform the fuel injection and the ignition.

On the other hand, if the time of combustion CA50 does not coincide with the target combustion time CA50, the ECU performs 10 Correcting the fuel injection amount, the fuel injection timing, the ignition timing, and the number of times of ignition by increasing or decreasing the fuel injection amount and / or advancing or retarding the timing of the ignition. In this case, the ECU controls 10 along with the corrected fuel injection amount, the corrected fuel injection timing, the corrected ignition timing, and the corrected number of times of the ignitions, the operation of the injector 23 and the spark plug 20 to perform the fuel injection and the ignition.

Now referring to 3 will be an exemplary program for performing the control for predicting the Timing of the combustion and the control of the ignition timing described. This program for carrying out the control of the timing of combustion and the control of the ignition timing is executed by the ECU 10 executed at predetermined intervals.

As in 3 illustrated by the ECU 10 based on the input of the detected result from the crank angle sensor 180 determines whether or not the time is favorable for various arithmetic operations performed in the control for the timing of combustion and the control of the ignition timing, and for measurements by various sensors (step S1). If it is determined that the time for these various arithmetic operations and for these measurements by different sensors is not favorable, the ECU repeats 10 the processing in step S1.

On the other hand, when it is determined that the time is favorable for these various arithmetic operations and for these measurements by various sensors, the ECU detects the engine operating conditions expressed by the engine speed Ne and the accelerator pedal position (step S2).

Next, the ECU detects 10 various detected values used in the control for predicting the timing of combustion and the control of the ignition timing, such as the intake air amount, the intake temperature T _in , the exhaust gas temperature T _ex, and the coolant temperature T _water (step S3).

Then the ECU calculates 10 based on the engine speed Ne, the engine load and the intake air amount, the basic fuel injection amount (step S4). Next, the ECU calculates 10 using the equation (5), the time of combustion CA50 (step S5).

Then the ECU determines 10 whether or not the timing of the combustion CA50 coincides with the target combustion time CA50 (step S6). As mentioned above, the determination as to whether or not the timing of the combustion CA50 coincides with the target combustion timing CA50 is determined by determining whether the timing of the combustion CA50 exactly coincides with the target combustion timing CA50 or the timing of the combustion CA50 falls within the tolerance range of the target combustion timing CA50.

When the time of combustion CA50 coincides with the target combustion time CA50, the program ends. In this case, the ECU controls 10 along with the fuel injection amount, the fuel injection timing, the ignition timing, and the number of times of ignition, which are determined from the fuel injection quantity characteristic, the fuel injection timing, the ignition timing, and the number of times of ignition, the operation of the injector 23 and the spark plug 20 to perform the fuel injection and the ignition.

On the other hand, if the time of combustion CA50 does not coincide with the target combustion time CA50, the ECU determines 10 Whether or not the timing of combustion CA50 is greater than the target combustion timing CA50, that is, whether the timing of combustion CA50 is delayed from the target combustion timing CA50 or not (step S7).

When the timing of combustion CA50 is delayed from the target combustion timing CA50, the ECU decreases 10 advancing the time of combustion CA50 (step S8). Specifically, the fuel injection amount, the fuel injection timing, the ignition timing and the number of times of ignition are corrected by, for example, increasing the fuel injection amount and advancing the ignition timing so as to advance the combustion timing CA50. This prescribes the time of combustion CA50.

On the other hand, if the time of combustion CA50 is not delayed from the target combustion time CA50, the ECU delays 10 the time of combustion CA50 (step S9). Specifically, the fuel injection amount, the fuel injection timing, the ignition timing, and the number of times of ignition are corrected by, for example, decreasing the fuel injection amount and retarding the ignition timing to retard the combustion timing CA50. This delays the time of combustion CA50.

The correction values for the fuel injection amount and the ignition timing used in step S8 and step S9 are determined experimentally and as correction characteristics for the fuel injection amount and the ignition timing in the ROM of the ECU 10 saved.

Then, after making such corrections of the time of combustion CA50 in step S8 or step S9, the ECU calculates 10 in step S5 again the time of combustion CA50 after the correction and determines whether the time of combustion CA50 after the correction coincides with the target combustion time CA50 or not. In this way, the timing of the combustion CA50 after the correction is corrected until the timing of the combustion CA50 after the correction coincides with the target combustion timing CA50.

Now referring to 4 The prediction accuracy of the combustion timing prediction system CA50 of the present embodiment will be described. 4 FIG. 15 is views to compare the prediction accuracy with which the timing of combustion CA50 is predicted using Equation (5) with the prediction accuracy with which the timing of combustion CA50 is predicted using the conventional Arrhenius equation.

In 4 (a) For example, the horizontal line labeled "CA50 calculated in degrees after top dead center" shows the time of combustion CA50 predicted using equation (5) and the vertical line labeled "CA50 measured in degrees after top dead center" actually measured time of combustion CA50.

In addition, shows in 4 (b) the horizontal line labeled "CA50 calculated in degrees after top dead center" indicates the time of combustion CA50 predicted using the conventional Arrhenius equation, and the vertical line labeled "CA50 measured in degrees after top dead center" actually measured time of combustion CA50. Each of these combustion CA50 times is an event occurring after top dead center.

Moreover, they are 4 (a) and 4 (b) Charts each indicating the correlation of the predicted time of combustion CA50 with the actually measured time of combustion CA50. In each diagram, the stronger the correlation of the predicted instant of combustion CA50 with the actually measured instant of combustion CA50 (a linear function with the slope "1"), the closer to the solid line, indicating each of the illustrated points in that the prediction accuracy of the time of combustion CA50 is high.

The degree of this correlation can be specified by the determination coefficient R ² (R squared). The more the correlation of the estimated time of combustion CA50 with the actually measured time of combustion CA50, the closer the determination coefficient R ² is to "1". Thus, the higher the prediction accuracy of the estimated time of combustion CA50, the closer the determination coefficient R ² is to "1".

Now, the determination coefficient R ² at the in 4 (a) It is closer to "1" than the determination coefficient R ² equal to 0.698 in the in 4 (b) shown diagram. Thus show 4 (a) and 4 (b) clearly that the prediction accuracy of the estimated time of combustion CA50 using equation (5) is higher than the prediction accuracy of the estimated time of combustion CA50 using the conventional Arrhenius equation.

Therefore, the combustion timing prediction system according to the present embodiment may have a higher prediction accuracy of the combustion timing CA50 than the combustion timing prediction system using the conventional Arrhenius equation.

As mentioned above, the combustion timing prediction system according to the present embodiment can predict the timing of the combustion CA50 more accurately than the prior art because arithmetic operations are performed after the combustion reaction parameters and the fuel condition parameters indicating the change of the combustion timing CA50 were included in the Arrhenius equation.

The combustion timing prediction system according to the present embodiment performs arithmetic operations after a plurality of combustion reaction parameters and a plurality of fuel condition parameters are included in the Arrhenius equation so that it can accurately predict the time of combustion CA50 even if the operating condition of the combustion CA50 Motors 2 changed.

In this way, the combustion timing prediction system according to the present embodiment can improve the accuracy of predicting the autoignition timing or the combustion timing CA50 occurring in the HCCI combustion as compared with the prior art.

Moreover, the combustion timing prediction system according to the present embodiment can more accurately predict the time of combustion CA50 because each of the combustion reaction parameters and each of the fuel condition parameters has the predetermined exponents.

When the exponents of each of the combustion reaction parameters and each of the fuel condition parameters are preliminary experimental can be determined, the system can predict the timing of combustion CA50 with good accuracy, adding individual differences, by specifications of the engine 2 be absorbed, absorbed.

Moreover, the combustion timing prediction system according to the present embodiment _uses the residual gas _content X _rg as the burned gas state variable. The residual gas contains nitrogen oxides and partially oxidized fuel, so that the thermodynamic properties such as the heat capacity ratio and the temperature differ from those of the fresh or intake air.

Thus, the amount of the residual gas can increase the temperature and change the chemical properties of the combustion inside the cylinder 21 cause the timing of CA50 burning to be affected. Therefore, the combustion timing prediction system improves the prediction accuracy of the combustion timing CA50 because arithmetic operations of the Arrhenius equation are performed using the residual gas _content X _rg .

Moreover, the combustion timing prediction system of the present embodiment uses the engine speed Ne as the mixed prediction variable. It is known that the mixing state of the fuel affects the combustion speed, and that the degree of mixing is different depending on the engine speed Ne.

Therefore, the combustion timing prediction system predicts the time of combustion CA50 more accurately because arithmetic operations of the Arrhenius equation are performed using the engine speed for the prediction of the mixed state of the fuel.

Moreover, the combustion timing prediction system according to the present embodiment uses a difference between the exhaust gas temperature T _ex and the intake temperature T _in as a heat loss prediction variable. It is noted that the difference between the exhaust gas temperature T _EX and the intake temperature T _in a correlation with the distribution of the gas temperature inside the cylinder 21 having. It is also known that the distribution of gas temperature inside the cylinder 21 is generated, the time of combustion CA50 influenced.

Therefore, the combustion timing prediction system according to the present embodiment can improve the prediction accuracy of the combustion timing CA50 because Arithmetic operations of the Arrhenius equation using the difference between the exhaust gas temperature T _ex and the intake temperature T _in , to determine the influence of the Inside of the cylinder 21 be taken into account generated distribution of the gas temperature.

In the present embodiment, all of the combustion reaction parameters and all of the fuel condition parameters are used to predict the timing of the combustion, but the present invention is not limited thereto. For example, when an engine is to be used, in which the distribution of the temperature and / or the distribution of the equivalence ratio inside the cylinder 21 may be relatively small, one of the following equations (6) to (8), after elimination of the influence of the distribution of the temperature and / or the distribution of the equivalence ratio inside the cylinder 21 from equation (5) can be used to predict the time of combustion CA50. CA50 = A · P _{cyl_10BTDC} ^B · φ ^C · X _rg ^D · (1 / Ne) ^F · EoI · ^H · exp (-E / RT _{cyl_10BTDC} ) (6) CA50 = A · P _{cyl_10BTDC} ^B · φ ^C · X _rg ^D · (1 / Ne) ^F · (T _ex - T _in ) ^G · exp (-E / RT _{cyl_10BTDC} ) (7) CA50 = A · P _{cyl_10BTDC} ^B · φ ^C · X _rg ^D · (1 / Ne) ^F · exp (-E / RT _{cyl_10BTDC} ) (8)

Moreover, if a motor can 2 is to be used, in which the influence of the turbulence / mixture is small, the following equation (9), in which the term dependent on the engine speed Ne is omitted, can be used to predict the time of combustion CA50. CA50 = A * P _{cyl_10BTDC} ^B * φ ^C * X _rg ^D * exp (-E / RT _{cyl_10BTDC} ) (9)

The equations (6) to (9) given above give exemplary varying variations in the combustion reaction parameters and fuel condition parameters given in equation (5) for different engine specifications 2 are used, but the modifications are not limited thereto.

For example, in the equation (5), the combustion timing prediction system according to the present embodiment may use at least two combustion _{reaction parameters selected} from the cylinder pressure P _{cyl_10BTDC} , the residual gas _fraction X _rg, and the equivalence _ratio φ.

Moreover, in the equation (5), the system for predicting the timing of combustion according to the present embodiment _{may select} at least one combustion _{reaction parameter selected} from the cylinder pressure P _{cyl_10BTDC} , the residual gas _content X _rg, and the equivalence _ratio φ, and at least one fuel _{condition parameter} derived from the engine speed Ne, the time EoI at which the injection of the fuel is completed and the difference (T _ex -T _in ) is selected.

Moreover, the combustion timing prediction system according to the present embodiment corrects the ignition timing and the number of times of ignition to advance or retard the combustion timing CA50, but it may be modified to include only the fuel injection amount and the fuel injection timing corrected.

Second embodiment

Next will be 5 used to describe a second embodiment of the present invention.

The present embodiment differs from the foregoing first embodiment only in a part of the processing of the control of the timing of combustion and the control of the ignition timing, while the remaining construction and the remaining processing are the same as those in the first embodiment. Therefore, a description of the same construction and the same processing as those of the first embodiment will be omitted below, and only the part which differs from the first embodiment will be described.

In the control for predicting the timing of combustion and the ignition timing control according to the first embodiment, the ECU repeats 10 the correction of the time of combustion CA50 until the time of combustion CA50 after the advancing correction in step S8 or the retarding correction in step S9 of FIG 3 coincides with the target combustion time CA50.

On the other hand, the ECU repeats 10 In the present embodiment, the correction of the timing of the combustion CA50 is not, but it performs the correction for the time of combustion CA50 only once in step S18 or S19.

In particular, ends like in 5 shown the program after the ECU 10 of the present embodiment, the pre-relocation correction has been performed in step S18. In addition, the program ends after the ECU 10 has performed the delaying correction in step S19.

Moreover, the ECU 10 for example, a correction characteristic which is a relation between a difference between the time of combustion CA50 and the target combustion time CA50 and the corresponding value of the increase of the fuel injection amount and the corresponding value Defining the Vorverlegungsausmaßes the ignition timing, perform only once. The above-mentioned correction characteristic with previously experimentally determined data is in the ROM of the ECU 10 saved.

Moreover, the ECU 10 as in the processing in step S18, the retard correction for the time of combustion CA50 in step S19 with reference to, for example, a correction characteristic that is a relationship between a difference between the time of combustion CA50 and the target combustion time CA50 and the corresponding value of the combustion Reduction of the fuel injection amount and the corresponding value of the delay amount of the ignition timing defined, perform only once.

Moreover, since the content at each of the steps S11 to S19 shown in FIG 5 are the same as the contents at the corresponding steps S1 to S9 in FIG 3 are, these steps are not described in the present embodiment.

As mentioned above, the combustion timing prediction system of the present embodiment provides the following technical effect in addition to the technical effects provided by the first embodiment. The processing load of the ECU 10 is reduced because the combustion timing prediction system according to the present embodiment only corrects the combustion timing CA50 once in step S18 and step S19 without repeating the correction of the combustion timing CA50.

Third embodiment

Next will be 6 used to describe a third embodiment of the present invention.

According to the above-mentioned first embodiment, the fuel injection amount, the fuel injection timing, the ignition timing, and the number of times of ignition are increased by increasing or decreasing the fuel injection amount and advancing or retarding the ignition timing Ignition timing corrects that the time of combustion CA50 can reach an optimal time.

If such a correction brings the timing of the combustion CA50 to the optimum timing, the burning time is shortened, causing noise and a problem in the strength of the engine. For example, increasing the cylinder pressure rise rate dP / dCA requires the shortened burning time.

Now, the burn time CA10 to CA90, the maximum cylinder pressure P _max and the pressure rise rate dP / DCA in the same manner as in the method for predicting the time of combustion in the previously described first embodiment can be predicted according to the present embodiment. The burning time CA10 to CA90 is the time or crank angle from the moment of mass fraction of combustion of 10% to the moment of mass fraction of combustion of 90% inside the cylinder.

Moreover, the ECU decreases 10 the fuel injection amount and delays the ignition timing based on the predicted pressure increase rate dP / dCA. This causes a reduction in the cylinder pressure, thereby limiting an increase in the pressure increase rate dP / dCA.

Now referring to 6 For example, a program for performing the prediction of the timing of combustion and the control of the ignition timing will be described. The processing from step 21 to step 25 shown in FIG 6 is the same as the processing from step 1 to step 5 used in the description of the first embodiment 3 is shown. Therefore, only that part of the processing different from the first embodiment will be described.

As in 6 shown determines the ECU 10 whether or not the combustion time CA50 calculated in step 25 coincides with a target combustion time CA50 (step S26). The determination as to whether the timing of combustion CA50 coincides with the target combustion timing CA50 or not is made in the same manner as in the first embodiment.

If the ECU 10 determines that the time of combustion CA50 coincides with the target combustion time CA50, the program proceeds to step S28. On the other hand, if the combustion timing CA50 does not coincide with the target combustion timing CA50, the ECU corrects 10 the time of combustion CA50 (step S27) and the program returns to step S25.

As a correction of the time of combustion CA50 increases or decreases the ECU 10 for example, the amount of fuel injection, and it advances or retards the ignition timing. This leads to a correction to advance or delay the time of combustion CA50.

In step S28, the ECU calculates 10 the pressure rise rate dP / dCA. Then, it is determined whether or not the calculated pressure increase rate dP / dCA is less than a target pressure rise rate (step S29). The target pressure rise rate is a pressure rise rate that allows the burning time to be prevented from becoming short, and this pressure rise rate has been experimentally found and stored in the ROM of the ECU 10 saved.

If the ECU 10 determines that the pressure increase rate dP / dCA is less than the target pressure rise rate, the program ends. On the other hand, when the pressure rise rate dP / dCA is not less than the target pressure rise rate or equal to or greater than the target pressure increase rate, the ECU will result 10 control to decrease the cylinder pressure (step S30), and the program returns to step S28.

As a control to reduce the cylinder pressure, the ECU 10 For example, a control to delay the timing of the combustion CA50 and reduce the fuel injection amount. This reduces the cylinder pressure.

Moreover, the auto-ignition in the HCCI combustion and the knock in the spark-ignition internal combustion engine can be regarded as the same event. Therefore, the combustion timing prediction method described in connection with each of the above-mentioned embodiments is applicable to the knock control for a spark-ignition internal combustion engine. For example, in such a knock control, instead of predicting the timing of combustion, it is predicted whether knocking will occur or not. In addition, the method of predicting the timing of the combustion may be applicable to the control of a pre-ignition that may occur at the time of charging. In this case, instead of predicting the timing of the combustion, it is predicted whether or not a pre-ignition occurs.

Although an embodiment of the present invention has been described, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the deviate from the present invention. All such modifications and their equivalents are intended to be covered by the following claims, which are described in the claims.

LIST OF REFERENCE NUMBERS

1

vehicle

2

Engine (HCCI combustion engine)

5

AGR system

10

ECU

20

spark plug

21

cylinder

23

injection

30

mechanical loader

101

Air flow sensor

102

intake temperature sensor

103

intake pressure

104

Intake O ₂ sensor

105

Cylinder pressure sensor

106

Exhaust gas temperature sensor

107

Air / fuel sensor

180

Crank angle sensor (A / F sensor)

181

Coolant temperature sensor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2009-168027 A [0006, 0007]
• US 2009/0182485 A1 [0006]
• DE 102008004361 A1 [0006]
• JP 2006-2637 A [0006, 0008]
• JP 2008-101591 A [0006, 0009]

Claims (12)

A system for predicting the timing of combustion of a mixture inside a cylinder for a stroke of an HCCI engine, comprising determining at least two combustion _{reaction parameters} from combustion _{reaction parameters} that determine a pressure state _variable (P _{cyl_10BTDC} ) based on a cylinder pressure inside the cylinder, a mass _{fraction of} fuel (φ, φ ^-1 ) determined based on the state of the fuel mass and the air mass inside the cylinder, and a state variable of the burnt gas (X _rg ) based on the retention of the burnt gas inside the cylinder is determined; Taking the determined two combustion reaction parameters into an Arrhenius equation; and predicting the timing of combustion (CA 50) for the power stroke using the Arrhenius equation. The system of claim 1, wherein an exponent of each of the determined two combustion reaction parameters is a predetermined number (B or C or D). A system for predicting a time of combustion of a mixture inside a cylinder for a power stroke of an HCCI internal combustion engine, comprising determining at least one combustion _{reaction parameter} from combustion _{reaction parameters} that includes a pressure state _variable (P _{cyl_10BTDC} ) determined based on a cylinder pressure inside the cylinder A fuel mass _fraction (φ, φ ^-1 ) determined based on the state of the fuel mass and the air mass inside the cylinder, and a burned gas state variable (X _rg ) determined based on the retention of the burnt gas inside the cylinder will include; Determining at least one fuel condition parameter from fuel condition parameters including a mixed prediction variable (Ne, Ne ^-1 ) for predicting the mixed state of the fuel inside the cylinder, an injection completion time (EoI) at which the injection of the fuel is completed, and a heat loss prediction variable (T _ex - T _in ) for predicting heat loss due to heat transfer between a wall surface and the fuel inside the cylinder; Taking the determined combustion reaction and fuel condition parameters into an Arrhenius equation; and predicting the timing of combustion (CA50) for the power stroke using the Arrhenius equation. The system of claim 3, wherein an exponent of each of said determined combustion reaction and fuel condition parameters is a predetermined number (B or C or D, F or G or H). A system according to any one of claims 1 to 4, wherein the mass fraction of fuel is an equivalence ratio or an inverse of the equivalence ratio (φ, φ ^-1 ). A system according to any one of claims 1 to 5, wherein the burned gas state variable is a percentage of the residual gas _mass relative to the mixture mass in the cylinder (X _rg ). A system according to any one of claims 3 to 6, wherein the mixing prediction variable is an engine speed of the engine or an inverse of the engine speed (Ne, Ne ^-1 ). A system according to any one of claims 3 to 7, wherein the heat loss prediction variable is a difference between an exhaust gas temperature and an intake temperature (T _ex - T _in ). A method for predicting the timing of combustion of a mixture inside a cylinder for a stroke of an HCCI engine, comprising determining at least two combustion _{reaction parameters} from combustion _{reaction parameters} that determine a pressure state _variable (P _{cyl_10BTDC} ) based on a cylinder pressure inside the cylinder, a mass _{fraction of} fuel (φ, φ ^-1 ) determined based on the state of the fuel mass and the air mass inside the cylinder, and a state variable of the burnt gas (X _rg ) based on the retention of the burnt gas inside the cylinder is determined; Taking the determined two combustion reaction parameters into an Arrhenius equation; and predicting the timing of combustion (CA50) for the power stroke using the Arrhenius equation. The method of claim 9, wherein an exponent of each of the determined two combustion reaction parameters is a predetermined number (B or C or D). A method for predicting a timing of combustion of a mixture inside a cylinder for a power stroke of an HCCI engine, comprising determining at least one combustion _{reaction parameter} from combustion _{reaction parameters including} a pressure state _variable (P _{cyl_10BTDC} ) based on a cylinder pressure inside the engine Cylinder, a mass _{fraction of} fuel (φ, φ ^-1 ) determined based on the state of the fuel mass and the air mass inside the cylinder and a state variable of the burned gas (X _rg ) based on the retention of the burnt gas inside the cylinder is determined; Determining at least one fuel condition parameter from fuel condition parameters including a mixed prediction variable (Ne, Ne ^-1 ) for predicting the mixed state of the fuel inside the cylinder, an injection completion time (EoI) at which the injection of the fuel is completed, and a heat loss prediction variable (T _ex - T _in ) for predicting heat loss due to heat transfer between a wall surface and the fuel inside the cylinder; Taking the determined combustion reaction and fuel condition parameters into an Arrhenius equation; and predicting the timing of combustion (CA50) for the power stroke using the Arrhenius equation. The method of claim 11, wherein an exponent of each of the determined combustion reaction and fuel condition parameters is a predetermined number (B or C or D, F or G or H).

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