JP2018091186A - Internal combustion engine parameter identification device, on-vehicle control system, and internal combustion engine parameter identification method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy of a calculation value of a cylinder internal pressure led out by using a Wiebe function.SOLUTION: An internal combustion engine parameter identification device includes a relational expression storing portion for storing a first relational expression of a heat generation rate by combustion in a cylinder of an internal combustion engine and a cylinder internal pressure of the internal combustion engine, an acquiring portion for acquiring an actual value of the cylinder internal pressure, a heat generation rate lead-out portion for leading out a calculation value of the heat generation rate on the basis of a Wiebe function, an initial value setting portion for setting an initial value of the cylinder internal pressure on the basis of a value of an initial value parameter, an internal pressure lead-out portion for leading out a calculation value of the cylinder internal pressure on the basis of the first relational expression, the calculation value of the heat generation rate, and the initial value, and a parameter identification portion for identifying a value of the initial value parameter on the basis of a relationship between the actual value of the cylinder internal pressure and the calculation value of the cylinder internal pressure.SELECTED DRAWING: Figure 15

Description

  The present disclosure relates to an internal combustion engine parameter identification device, an in-vehicle control system, and an internal combustion engine parameter identification method.

  There is known a method of deriving a calculated value of in-cylinder pressure using a Wiebe function that models a heat generation rate due to combustion in a cylinder of an internal combustion engine.

JP 2007-239524 JP JP 2008-255932 A

  However, with the conventional technology, it is difficult to increase the accuracy of the calculated value of the in-cylinder pressure that can be derived using the Wiebe function. This is because the Wiebe function cannot reproduce the heat generation rate in a period before the combustion start timing (that is, a period after the intake valve closing timing and before the combustion start timing).

  Accordingly, in one aspect, an object of the present invention is to improve the accuracy of the calculated value of the in-cylinder pressure derived using the Wiebe function.

In one aspect, a relational expression storage unit that stores a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure of the internal combustion engine;
An acquisition unit for acquiring an actual measurement value of the in-cylinder pressure;
Based on a Wiebe function, a heat generation rate deriving unit for deriving a calculated value of the heat generation rate,
An initial value setting unit for setting an initial value of the in-cylinder pressure based on a value of an initial value parameter;
An in-cylinder pressure deriving unit for deriving the calculated value of the in-cylinder pressure based on the first relational expression, the calculated value of the heat generation rate, and the initial value;
An internal combustion engine parameter identification device is provided that includes a parameter identification unit that identifies the value of the initial value parameter based on the relationship between the actually measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure.

  In one aspect, according to the present invention, it is possible to increase the accuracy of the calculated value of the in-cylinder pressure derived using the Wiebe function.

It is a figure which shows the relationship between a Wiebe function and a combustion rate. It is a figure which shows the relationship between a Wiebe function and a heat release rate. It is a figure which shows the relationship between the Wiebe function in the case of three-stage injection, and a heat release rate. It is explanatory drawing of the identification object period of a Wiebe function parameter. It is explanatory drawing of the identification object period of an initial value correction parameter. It is explanatory drawing of the subject in a comparative example. It is explanatory drawing of the reproduction characteristic of the heat release rate by a Wiebe function. It is explanatory drawing of the verification result by the test conditions 1. FIG. FIG. 6 is an explanatory diagram of a verification result under test condition 1. FIG. 6 is an explanatory diagram of a verification result under test condition 1. It is explanatory drawing of the verification result by the test conditions 2. FIG. It is explanatory drawing of the verification result by the test conditions 2. FIG. It is explanatory drawing of the verification result by the test conditions 2. FIG. It is explanatory drawing of the verification result by the test conditions 3. FIG. It is explanatory drawing of the verification result by the test conditions 3. FIG. It is explanatory drawing of the verification result by the test conditions 3. FIG. It is a figure which shows an example of the vehicle-mounted control system containing a parameter identification apparatus. It is a figure which shows an example of driving | operation data. It is a figure which shows an example of the hardware constitutions of a parameter identification apparatus. It is a figure which shows notionally an example of the data in a model parameter memory | storage part. It is a flowchart which shows an example of the process performed by the parameter identification apparatus. It is a flowchart which shows an example of the process performed by an engine control apparatus. It is a figure which shows another example of the vehicle-mounted control system containing a parameter identification apparatus.

  Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

  Here, first, basic items of the Wiebe function will be described with reference to FIGS. 1A and 1B.

  FIG. 1A is a diagram showing the relationship between the Wiebe function and the combustion rate. FIG. 1B is a diagram showing the relationship between the Wiebe function and the heat generation rate.

The Wiebe function is known as an approximate function of a heat generation pattern (combustion waveform). Specifically, the Wiebe function is a function that approximates the profile of the combustion rate _xb calculated from the combustion pressure, and is given by the following equation with respect to the crank angle θ.

ここで、a、mは、それぞれ形状指数、θ_socは、燃焼開始時期(Start of Combustion)、Δθは燃焼期間をそれぞれ表す。このa、m、θ_soc、及びΔθの4つのパラメータは、Wiebe関数パラメータと呼ばれる。図１Ａには、Wiebe関数と燃焼率ｘ_ｂの関係が示され、横軸がクランク角度θであり、縦軸が燃焼率ｘ_ｂである。これら4つのWiebe関数パラメータを用いて筒内の熱発生率(Rate of Heat Release)の算出値ROHR_calc（以下、単に「熱発生率ROHR_calc」とも表記する）は、次式のように表現される。

Here, a and m are the shape index, θ _soc is the combustion start time (Start of Combustion), and Δθ is the combustion period, respectively. The four parameters a, m, θ _soc , and Δθ are called Wiebe function parameters. FIG. 1A shows the relationship between the Wiebe function and the combustion rate _xb , where the horizontal axis is the crank angle θ and the vertical axis is the combustion rate _xb . Using these four Wiebe function parameters, the calculated value of heat release rate (Rate of Heat Release) ROHR _calc (hereinafter also simply referred to as “heat generation rate ROHR _calc ”) is expressed as follows: The

ここで、Q_bは、筒内の総熱発生量である。総熱発生量Q_ｂの値は、燃料噴射量等に基づいて算出される値が用いられてよい。
併せて、燃焼開始時期θ_socからある時期Θまでの発生した総熱発生量は下式で表される。

Here, Q _b is the total heat generation quantity in the cylinder. The value of the total heat generation amount Q _b is a value calculated based on the fuel injection amount or the like may be used.
In addition, the total amount of heat generated from the combustion start time θ _soc to a certain time Θ is expressed by the following equation.

図１Ｂには、Wiebe関数と熱発生率dQ_b/dθの関係が示され、横軸がクランク角度θであり、縦軸が熱発生率dQ_b/dθである。図１Ｂには、クランク角度θ＝Θであるときの総発生熱量HR(Θ)がハッチング範囲で示されている。

FIG. 1B shows the relationship between the Wiebe function and the heat generation rate dQ _b / dθ, where the horizontal axis is the crank angle θ and the vertical axis is the heat generation rate dQ _b / dθ. FIG. 1B shows the total heat generation amount HR (Θ) in the hatched range when the crank angle θ = Θ.

Here, if the value of the Wiebe function parameter to be identified is the value of the four Wiebe function parameters a, m, θ _soc , and Δθ in the equation (2), the value of the Wiebe function parameter to be identified is 4 It is a piece. Note that the value of the combustion ratio xf may also be included in the value of the Wiebe function parameter to be identified. For example, the Wiebe function parameter a may be a fixed value such as 6.9. Hereinafter, these values of the Wiebe function parameters a, m, θsoc, and Δθ are referred to as a value, m value, θ _soc value, and Δθ value, respectively.

The value of each Wiebe function parameter such as the a value, the m value, the θ _soc value, and the Δθ value, for example, is identified so that the error of the heat generation rate ROHR _{calc with} respect to the heat generation rate ROHR _sensor is minimized. Specifically, the evaluation formula (evaluation function) for identifying the value of the Wiebe function parameter is as follows. In this case, the value of each Wiebe function parameter is identified so that the sum of squared errors of the heat generation rate ROHR _{calc with} respect to the heat generation rate ROHR _sensor is minimized. At this time, each value of the Wiebe function parameter that minimizes the evaluation function F may be derived by optimization calculation using an interior point method, a sequential programming method, or the like.

ここで、熱発生率ROHR_sensorは、運転データ（実測筒内圧）に基づく熱発生率である。熱発生率ROHR_calcは、Wiebe関数から得られる熱発生率である。Σは、積算を表す。なお、θ_EVOは、排気弁開時期（Exhaust valve opening）を表す。Wiebe関数パラメータの同定対象期間の開始時期は、燃焼開始時期θ_socであるが、同定に用いる実測筒内圧データは、燃焼開始時期θ_socよりも前の時期からのデータ（例えば燃料噴射時期θ_SOIからのデータ）であってもよい。図３Ａは、Wiebe関数パラメータの同定対象期間の説明図である。図３Ａには、Wiebe関数パラメータの同定対象期間は、期間Ｒ１で示される。図３Ａには、図２と同様、縦軸を熱発生率、横軸をクランク角度として、熱発生率ROHR_calcの波形（履歴）が示される。この場合、Wiebe関数パラメータの同定対象期間は、期間Ｒ２で示され、燃焼開始時期θ_socから排気弁開時期θ_EVOまでである。

Here, the heat generation rate ROHR _sensor is a heat generation rate based on operation data (measured in-cylinder pressure). Heat generation rate ROHR _calc is a heat generation rate obtained from the Wiebe function. Σ represents integration. Θ _EVO represents the exhaust valve opening timing (Exhaust valve opening). The start timing of the Wiebe function parameter identification target period is the combustion start timing θ _soc , but the measured in-cylinder pressure data used for the identification is data from a timing before the combustion start timing θ _soc (for example, the fuel injection timing θ _SOI Data). FIG. 3A is an explanatory diagram of an identification target period of the Wiebe function parameter. In FIG. 3A, the identification target period of the Wiebe function parameter is indicated by a period R1. FIG. 3A shows a waveform (history) of the heat generation rate ROHR _{calc with} the vertical axis representing the heat generation rate and the horizontal axis representing the crank angle, as in FIG. In this case, the identification target period of the Wiebe function parameter is indicated by a period R2, and is from the combustion start timing θ _soc to the exhaust valve opening timing θ _EVO .

The heat release rate ROHR _sensor can be derived using the following relationship based on the measured in-cylinder pressure data obtained in the test. Heat generation rate ROHR _sensor represents an apparent heat generation rate.

ここで、γは比熱比、Pは筒内圧、Vは筒内体積である。例えば、γの値は、燃焼ガスの組成などに基づいて定まる既知の値が用いられてよい。熱発生率ROHR_sensorの算出には、筒内圧Ｐは、実測筒内圧データに基づく値が用いられる。筒内体積Ｖ、及びその変化率ｄＶ／ｄθの各値は、クランク角度θに応じて幾何的に定まる値が用いられてよい。

Here, γ is the specific heat ratio, P is the in-cylinder pressure, and V is the in-cylinder volume. For example, a known value determined based on the composition of the combustion gas or the like may be used as the value of γ. In calculating the heat release rate ROHR _sensor , the in-cylinder pressure P is a value based on measured in-cylinder pressure data. As the values of the in-cylinder volume V and the rate of change dV / dθ, values determined geometrically according to the crank angle θ may be used.

However, for the identification of the Wiebe function parameter, the true heat generation rate ROHR _true corrected in consideration of heat loss may be used instead of the apparent heat generation rate ROHR _sensor . In this case, the heat generation rate ROHR _true may be derived by adding the heat loss HL _actual to the heat generation rate ROHR _sensor obtained by the equation (5). That is, it is as follows.
ROHR _true = ROHR _sensor + HL _actual
Heat loss HL _actual can be derived on the basis of the operating data (actually measured cylinder pressure data). For example, the _actual heat loss HL (θ) corresponding to the crank angle can be derived by an empirical formula that predicts an average heat transfer coefficient on the cylinder wall surface using actually measured in-cylinder pressure data. For example, heat loss HL _actual can be expressed by the following equation.

数６の１番目の式は、シリンダ壁面への熱伝達率を表し、Cは実験定数、Wは燃焼室内ガス流動の効果、dはボア径である。mには0.8が用いられた経験式として、数６の２番目の式が知られている。数６の３番目の式において、Tはシリンダ内ガス温度、T_wはシリンダ壁面温度、Nは機関回転数、A_wはシリンダ壁面積、Pは筒内圧である。尚、ｔは時間であり、クランク角度θと実質的に等価である。Ｐの値は、実測筒内圧データに基づく値（クランク角度θに応じた値）が用いられる。

The first expression of Equation 6 represents the heat transfer coefficient to the cylinder wall surface, C is an experimental constant, W is the effect of gas flow in the combustion chamber, and d is the bore diameter. As an empirical formula in which 0.8 is used for m, the second formula of Equation 6 is known. In the third expression of Equation 6, T is the gas temperature in the cylinder, T _w is the cylinder wall temperature, N is the engine speed, A _w is the cylinder wall area, and P is the cylinder pressure. Note that t is time and is substantially equivalent to the crank angle θ. As the value of P, a value based on actually measured in-cylinder pressure data (a value corresponding to the crank angle θ) is used.

In the following, when identifying the Wiebe function parameters, a method of using the heat generation rate ROHR _true corrected in consideration of heat loss instead of the heat generation rate ROHR _sensor, to express in particular, `` considering heat loss Identification method ". On the other hand, when identifying the Wiebe function parameter, a method using the heat generation rate ROHR _sensor is particularly referred to as “identification method not taking heat loss into account”. According to the identification method taking heat loss into account, it is possible to accurately reproduce the heat generation rate ROHR _sensor representing the apparent heat generation rate based on the Wiebe function. This is because the Wiebe function cannot take a negative value as shown in FIG. 1B or Equation 2 and has a region where the apparent heat generation rate is negative (that is, a region where heat loss greater than the heat generation rate occurs). This is because it cannot be expressed.

As a modeling method using the Wiebe function, there is also a modeling method using a combination of a plurality of Wiebe functions. For example, the heat generation rate in the case of multistage injection such as a diesel engine is obtained by superimposing the heat generation rates of the respective stages, and therefore can be accurately expressed by using a plurality of Wiebe functions. FIG. 2 shows a waveform (hereinafter also referred to as “combustion waveform”) showing the relationship between the crank angle θ and the heat generation rate in a diesel engine that performs three-stage injection. FIG. 2 shows a combustion waveform related to the combustion by the pre-injection by the first-stage injection, a combustion waveform related to the combustion by the second-stage main injection, the first combustion and the second combustion of the combustion by the third-stage after-injection. Each combustion waveform relating to combustion (diffusion combustion) and a combined waveform thereof are shown. In FIG. 2, θ _SOC1 represents the combustion start timing related to the combustion by the first-stage pre-injection.

  For example, in the case of the three-stage injection as shown in FIG. 2, for example, a modeling method using a combination of N + 1 Wiebe functions may be used as follows. In this case, N = 3 and a combination of four Wiebe functions may be used. That is, N corresponds to the number of injections.

ここで、xfは、燃焼割合である。数７の式は、数２の式を、燃焼割合xfを乗じた形でN+1個組み合わせた式に対応する。即ち、数７の式は、ｉ＝ｋに係るWiebe関数（但し、ｋは、１〜Ｎ＋１の任意の数）を、燃焼割合xfを乗じた形でN+1個組み合わせた式に対応する。以下、複数のWiebe関数を組み合わせた関数を特に言及するときは、「組み合わせWiebe関数」と称する。

Here, xf is a combustion rate. Equation 7 corresponds to an equation in which N + 1 is combined with Equation 2 multiplied by the combustion ratio xf. That is, the equation of Equation 7 corresponds to an equation obtained by combining N + 1 Wiebe functions related to i = k (where k is an arbitrary number from 1 to N + 1) multiplied by the combustion ratio xf. Hereinafter, when a function obtained by combining a plurality of Wiebe functions is specifically referred to, it is referred to as a “combination Wiebe function”.

  According to such a modeling method using the combined Wiebe function, high-precision modeling is possible even when a plurality of combustion modes having different combustion types exist in one cycle. For example, the modeling method of Equation 7 is suitable when there are N + 1 combustion forms with different combustion types in one cycle. The combustion modes with different combustion types are, for example, combustion modes in which the relationship between the crank angle θ and the heat generation rate is significantly different as shown in FIG. 1B. In addition, since the heat release rate in the case of multistage injection such as the latest diesel engine is a superposition of the heat release rates of the respective stages, a modeling method using a combined Wiebe function is useful. However, not only a diesel engine but also a gasoline engine or the like, a plurality of combustion modes having different combustion types may exist in one cycle. Therefore, the modeling method using the combined Wiebe function can be applied to other engines such as a gasoline engine.

Here, in the equation (7), if the values of the Wiebe function parameters to be identified are the values of the four Wiebe function parameters a, m, θ _soc , and Δθ, there are N + 1 Wiebe functions. The value of the Wiebe function parameter to be identified is 4 × (N + 1). Note that the value of the combustion ratio xf may also be included in the value of the Wiebe function parameter to be identified. For example, the Wiebe function parameter a may be a fixed value such as 6.9.

Similarly, in the case of the combined Wiebe function, the evaluation function F shown in Equation 4 may be used as the evaluation formula (evaluation function) for identifying the value of the Wiebe function parameter. In this case, the heat release rate ROHR _calc is calculated based on the equation (7). Alternatively, in order to increase the accuracy of parameter identification, the sum of squares of error of heat generation amount HR, the difference in m value between Wiebe functions related to two combustion modes with different combustion types, and the Δθ value between the Wiebe functions Differences may be included. For example, in this case, the evaluation function F may be as follows, for example.

数８の式において、Σは、積算を表す。ここで、中括弧内の第1項は、熱発生率(ROHR)に関する評価値であり、上記の数４に示した評価関数Ｆと同じである。但し、この場合、熱発生率ROHR_calcは、数７の式に基づいて算出される。中括弧内の第２項は、熱発生量HRの誤差二乗和である。尚、ＨＲ_calcは、数３の式から得られる。但し、この場合、数３の式のROHR_calcは、数７の式に基づく。ＨＲ_sensorは、以下のとおりである。中括弧内の第３項は、ｉ番目の燃焼形態に係るWiebe関数のｍ値とｋ番目の燃焼形態に係るWiebe関数のｍ値との差分に関する評価値である。ｗ_１及びｗ_２は、重みである。

In the equation (8), Σ represents integration. Here, the first term in the curly braces is an evaluation value related to the heat release rate (ROHR), which is the same as the evaluation function F shown in Equation 4 above. However, in this case, the heat release rate ROHR _calc is calculated based on the formula (7). The second term in the braces is the sum of squared errors of the heat generation amount HR. HR _calc is obtained from the equation (3). However, in this case, the ROHR _calc of the formula 3 is based on the formula 7. The HR _sensor is as follows. The third term in the curly braces is an evaluation value relating to the difference between the m value of the Wiebe function related to the i th combustion mode and the m value of the Wiebe function related to the k th combustion mode. w ₁ and w ₂ are weights.

  In another embodiment, the evaluation function F may be as follows, for example.

数１０の評価関数Ｆの場合、中括弧内の第２項は、ｉ番目の燃焼形態に係るWiebe関数のΔθ値とｋ番目の燃焼形態に係るWiebe関数のΔθ値との差分に関する評価値である。

In the case of the evaluation function F of Equation 10, the second term in the curly braces is an evaluation value relating to the difference between the Δθ value of the Wiebe function related to the i th combustion mode and the Δθ value of the Wiebe function related to the k th combustion mode. is there.

Each Wiebe function parameter included in Equation 7 is identified as a value that minimizes the evaluation function F. At this time, the value of each Wiebe function parameter that minimizes the evaluation function F may be derived by optimization calculation using an interior point method, a sequential programming method, or the like. In addition, other constraint conditions may be added during the optimization calculation. Other constraints, for example, the sum that is about 1 and the combustion ratio xf _i, etc. larger than the combustion rate xf of Wiebe functions combustion ratio xf of Wiebe functions associated with the main combustion according to the other combustion May include.

  Next, a method for deriving the calculated value of the in-cylinder pressure based on the Wiebe function in which the value of the Wiebe function parameter has been identified as described above will be described. In the above description, the combined Wiebe function is described. However, the method for deriving the calculated value of the in-cylinder pressure described below can also be applied when a single Wiebe function is used.

The calculated value P _calc of the in-cylinder pressure can be derived from the following formula (an example of the first relational expression). In addition, the form of Formula 11 is obtained by converting Formula 5 into a differential equation related to in-cylinder pressure.

The heat generation rate ROHR used in Equation 11 is an _apparent heat generation rate ROHR, and is derived and determined as follows. The heat release rate ROHR _apparent after the combustion start time θ _SOC is calculated based on the Wiebe function. At this time, when the Wiebe function parameter is identified by an identification method taking heat loss into account, the heat generation rate ROHR _apparent may be calculated as ROHR _apparent = ROHR _calc −HL _actual . When the Wiebe function parameter is identified by an identification method that does not take heat loss into consideration, the heat generation rate ROHR _apparent may be ROHR _apparent = ROHR _calc .

On the other hand, a predetermined value is used as the _apparent heat generation rate ROHR in the period before the combustion start timing θ _SOC . The predetermined value may be a value that is varied over a period before the combustion start timing θ _SOC or may be a constant value that is constant over the same period. When it is a constant value, the predetermined value is preferably 0 or a value close to 0. This is because the heat generation rate before the combustion start timing θ _soc is substantially 0 (see the part X in FIG. 5). Alternatively, when the Wiebe function parameter is identified by an identification method taking heat loss into account, −HL _actual may be used as the predetermined value (that is, ROHR _apparent = ROHR _calc −HL _actual = 0−HL). _Actual = -HL _actual ). In the following, as an example, unless otherwise specified, the Wiebe function parameter is identified by an identification method that does not take heat loss into account, and the predetermined value is a constant value over a period before the combustion start timing θ _SOC , Assume that it is zero.

Here, in order to derive the calculated value P _calc of the in-cylinder pressure from the equation (11), numerical integration is used. For example, derivation of the calculated value P _calc of the in-cylinder pressure from the formula 11 involves the numerical integration of the _apparent heat release rate ROHR. In order to perform the numerical integration according to the equation (11), it is necessary to set the initial value P ₀ (the value at the beginning of the integration interval) of the in-cylinder pressure. The initial value P ₀ of the in-cylinder pressure is the in-cylinder pressure at an arbitrary start timing θs after the intake valve closing timing θ _{IVC and} before the combustion start timing θ _SOC (hereinafter simply referred to as “start timing θ _S ”). Represents a value. Start timing theta _S is arbitrary as long as the combustion start timing theta _SOC previously a intake valve closing timing theta _IVC after, preferably, certain easy intake valve closing timing theta _IVC. Hereinafter, as an example, it is assumed that the start timing θ _S = the intake valve closing timing θ _IVC .

In this embodiment, the initial value P ₀ is calculated by the following equation (hereinafter also referred to as “correction equation”).

ここで、P_Ｓは、開始時期θ_Ｓでの筒内圧の実測値である。ΔPは、筒内圧の初期値補正パラメータ（初期値パラメータの一例）であり、正又は負の値である。このように、初期値P_０は、開始時期θ_Ｓでの筒内圧の実測値P_Ｓに、初期値補正パラメータΔPを加算することで得られる値である。即ち、本実施例では、初期値P_０として、開始時期θ_Ｓでの筒内圧の実測値P_Ｓをそのまま用いるのではなく、初期値補正パラメータΔPが加算（初期値補正パラメータΔPで補正）された値が用いられる。

Here, P _S is the measured value of the in-cylinder pressure at the start timing theta _S. ΔP is an in-cylinder pressure initial value correction parameter (an example of an initial value parameter), and is a positive or negative value. Thus, the initial value P ₀ is a value obtained by adding the initial value correction parameter ΔP to the actually measured value P _S of the in-cylinder pressure at the start timing θ _S. That is, in this embodiment, as an initial value P _0, instead of directly using the measured values P _S of the in-cylinder pressure at the start timing theta _S, is the initial value correction parameter [Delta] P is added (corrected by the initial value correction parameter [Delta] P) Values are used.

As the value of the initial value correction parameter ΔP, the error evaluation value of the calculated value P _calc with respect to the measured value P _sensor of the in-cylinder pressure over a predetermined identification target period (hereinafter referred to as “identification target period of the initial value correction parameter”) is minimum. The value identified to be is used. An evaluation formula (evaluation function) for identifying the value of the initial value correction parameter ΔP is, for example, as follows. In this case, the identification target period of the initial value correction parameter is from the intake valve closing timing θ _IVC to the exhaust valve opening timing θ _EVO . Therefore, the value of the initial value correction parameter ΔP is identified so that the sum of squared errors of the calculated value P _calc with respect to the actual measurement value P _sensor is minimized over the period from the intake valve closing timing θ _IVC to the exhaust valve opening timing θ _EVO . At this time, the value of the initial value correction parameter ΔP that minimizes the evaluation function F1 may be derived by optimization calculation using an interior point method, a sequential programming method, or the like.

ここで、数１３において同定するパラメータは初期値補正パラメータΔPのみであるため、数１１を含む最適化計算の負荷は少なくて済む。尚、実測値Ｐ_sensorは、実測筒内圧データに基づく値が用いられる。

Here, since the parameter identified in Equation 13 is only the initial value correction parameter ΔP, the load of optimization calculation including Equation 11 can be reduced. As the actual measurement value P _sensor , a value based on the actual in-cylinder pressure data is used.

FIG. 3B is an explanatory diagram of the identification target period of the initial value correction parameter. In FIG. 3B, the vertical axis is the in-cylinder pressure, the horizontal axis is the crank angle, the waveform (history) of the calculated value P _calc of the in-cylinder pressure is a solid line, and the waveform (history) of the measured value P _sensor of the in-cylinder pressure is a solid line. Each is shown. In this case, the identification target period of the initial value correction parameter ΔP is indicated by a period R3, and is from the start timing θ _S (= intake valve closing timing θ _IVC ) to the exhaust valve opening timing θ _EVO .

  Next, with reference to FIGS. 4 to 14, the effect of the above-described embodiment will be described in comparison with the comparative example.

In the comparative example, the calculated value P _{calc of the in-} cylinder pressure is derived from the equation (11) using the same time series (history) of the heat release rate ROHR _calc as in this example. At this time, in the comparative example, the initial value P ₀ is calculated. is a _{P 0} = P _S. That is, in this embodiment, based on the initial value correction parameter [Delta] P that are identified as described above, corrected initial value _{P 0 (= P S + ΔP} ) is used for the measured value P _S of the start timing theta _S whereas is, in the comparative example, the measured value P _S of the start timing theta _S is used as the initial value P _0.

FIG. 4 is a diagram showing the waveform (solid line) of the calculated value P _calc (θ) of the in-cylinder pressure in the case of the comparative example, together with the waveform (broken line) of the actually measured value P _sensor (θ) of the in-cylinder pressure. FIG. 4 shows the same waveform from the intake valve closing timing θ _IVC to the exhaust valve opening timing θ _EVO . As can be seen from FIG. 4, the comparative example has a problem that the calculated value P _calc (θ) is significantly lower than the actually measured value P _sensor (θ) of the in-cylinder pressure.

As a result of examining the cause of such a problem, the inventor of the present application has considered that the Wiebe function cannot reproduce the heat generation rate in the period before the combustion start timing θ _SOC . This will be described more specifically with reference to FIG. In FIG. 5, the waveform of the heat release rate ROHR _calc calculated from the Wiebe function is shown by a solid line, and the waveform of the heat release rate ROHR _sensor based on the actually measured in-cylinder pressure is shown by a broken line. Due to its characteristics, the Wiebe function can be accurately reproduced for the period R1 from the combustion start timing θ _SOC to the exhaust valve opening timing θ _EVO, but cannot be reproduced for the period R2 from the intake valve close timing θ _IVC to the combustion start timing θ _SOC. (See part X).

For this reason, in the period R1 from the combustion start timing θ _SOC to the exhaust valve opening timing θ _EVO , the calculated value P _calc of the in-cylinder pressure can be derived based on the Wiebe function, but in the period R2, the calculated value P of the in-cylinder pressure P _calc cannot be derived based on the Wiebe function. When the calculated value P _calc of the in-cylinder pressure is derived based on the Wiebe function within the period R1 from the combustion start timing θ _SOC to the exhaust valve opening timing θ _EVO , as described above, the numerical integration according to the equation 11 is performed. Because of the relationship to be performed, it is necessary to set the initial value P ₀ of the cylinder pressure. In this case, the initial value P ₀ of the in-cylinder pressure is a value of the in-cylinder pressure at a time before the combustion start time θ _SOC .

However, the actually measured value of the in-cylinder pressure before the combustion start timing θ _SOC does not substantially contribute to the parameter identification of the Wiebe function. Therefore, when the actually measured value is used as it is as the initial value P ₀ of the in-cylinder pressure, The problem in the above-mentioned comparative example will arise.

Further, as can be seen from the form of the differential equation of Equation 11, a slight change in the initial value P ₀ has a relatively large influence on the calculated value P _calc (θ) of the in-cylinder pressure when the in-cylinder volume V decreases. This is easy, in the method of using a measured value P _S of the in-cylinder pressure as an initial value P ₀ (Comparative Example), it means that it is possible to enhance the accuracy of the calculated value of the cylinder pressure is derived using the Wiebe function To do.

In this respect, according to this embodiment, as described above, as the initial value P ₀ of the integral calculation in accordance with equation number 11, corrected by the initial value correction parameter ΔP relative to the measured value P _S of the start timing theta _S The initial value P ₀ (= P _S + ΔP) is used. The initial value correction parameter ΔP is identified so as to minimize the evaluation function F1. Therefore, according to the present embodiment, the initial value P ₀ that minimizes the evaluation function F1 (Equation 13) can be used. This means that the error of the calculated value P _calc with respect to the actually measured value P _sensor during the combustion period is reduced, and the accuracy of the calculated value of the in-cylinder pressure derived using the Wiebe function can be increased even during the combustion period.

By the way, in the method (hereinafter referred to as “identification method 1”) in which the Wiebe function is incorporated into the formula 11 and the value of the Wiebe function parameter that minimizes the error evaluation value for the measured value P _sensor of the in-cylinder pressure is identified. The calculation load is significantly increased. This requires that the optimization calculation including the differential equation related to the in-cylinder pressure of Equation 11 be performed with an increased number of Wiebe function parameters (for example, four parameters a, m, θ _soc , and Δθ) to be identified. Because. When the combination Wiebe function is used, the number of Wiebe function parameters further increases, and the calculation load can be enormous.

In this regard, according to the present embodiment, identification of the value of the Wiebe function parameter that minimizes the error evaluation value for the heat release rate ROHR _sensor , and the error evaluation value for the measured value P _{sensor of the in-} cylinder pressure. The identification of the initial value correction parameter that minimizes is performed separately. The computational load for identifying the Wiebe function parameter values is normal. Further, as described above, the calculation load for identifying the initial value correction parameter is only the initial value correction parameter ΔP, so that the calculation load for the optimization calculation including Equation 11 can be small. As a result, according to the present Example, compared with said identification method 1, calculation load can be reduced significantly.

  In this way, according to the present embodiment, the accuracy of the calculated value of the in-cylinder pressure derived using the Wiebe function can be increased without significantly increasing the calculation load for identifying the Wiebe function parameter. .

  The inventor of the present application verified a significant difference between the present example and the comparative example (that is, the effect of the present example) using actual in-cylinder pressure data.

Specifically, as a first verification, operation data (test condition 1) for three-stage combustion at a rotational speed of 1600 rpm was obtained from an inline 4-cylinder 3000 cc direct injection diesel engine on an engine bench. Then, the value of the Wiebe function parameter is identified by the equation (4) with respect to the heat release rate ROHR _true calculated by the equations (5) and (6) from the actually measured value P _sensor of the cylinder pressure obtained by the cylinder pressure _sensor . The heat release rate ROHR _apparent was calculated using Equation 7 and the value of the Wiebe function parameter. The Wiebe function parameters were identified by an identification method that considered heat loss. FIG. 6 shows the _apparent heat release rate ROHR calculated from the value of the identified Wiebe function parameter. In FIG. 6, the heat generation rate ROHR _apparent is indicated by a solid line, and the heat generation rate ROHR _sensor is indicated by a broken line. It can be seen from FIG. 6 that even the heat generation rate history of a complicated shape that is the three-stage combustion can be identified with high accuracy.

Therefore, based on the _apparent heat release rate ROHR obtained from the Wiebe function having the value of the identified Wiebe function parameter and the differential equation related to the in-cylinder pressure in Equation 11, numerical integration is used to open the exhaust valve from the intake valve closing timing θ _IVC. The calculated value P _calc of the in-cylinder pressure up to the timing θ _EVO was derived.

At this time, in the comparative example, P ₀ = P _IVC = 150 [kPa]. FIG. 7 shows the result of deriving the calculated value P _calc of the in-cylinder pressure according to the comparative example. In FIG. 7, the calculated value P _calc of the in-cylinder pressure is indicated by a solid line, and the actually measured value P _sensor of the in-cylinder pressure is indicated by a broken line. In the comparative example, the calculated value P _calc of the in-cylinder pressure was about 1 [MPa] lower than the measured value P _sensor of the in-cylinder pressure by the in-cylinder pressure _sensor .

In this embodiment, the value of the initial value correction parameter ΔP is identified by the optimization calculation from the equation (13). The value of the initial value correction parameter ΔP at this time was 27 [kPa]. The initial value P ₀ (= P _S + ΔP) of the in-cylinder pressure is calculated from the above correction equation using the value of the initial value correction parameter ΔP, and the result of deriving the calculated value P _calc of the in-cylinder pressure is shown in FIG. Indicated. In FIG. 8, the calculated value P _calc of the in-cylinder pressure is indicated by a solid line, and the actually measured value P _sensor of the in-cylinder pressure is indicated by a broken line. As shown in FIG. 8, according to the present embodiment, it can be seen that the calculated value P _calc of the in-cylinder pressure substantially coincides with the actually measured value P _{sensor of the in-} cylinder pressure.

Further, as a second verification, the results of verification in single-stage combustion (test condition 2) at a rotational speed of 1200 rpm in an in-line four-cylinder 3000 cc direct injection diesel engine are shown in FIGS. 9 to 11. FIG. 9 shows the _apparent heat generation rate ROHR calculated from the value of the identified Wiebe function parameter. In FIG. 9, the heat generation rate ROHR _apparent is shown by a solid line, and the heat generation rate ROHR _sensor is shown by a broken line. FIG. 9 shows that even the heat release rate history of single-stage combustion can be identified with high accuracy. FIG. 10 shows the result of deriving the calculated value P _calc of the in-cylinder pressure by the comparative example. In FIG. 10, the calculated value P _calc of the in-cylinder pressure is indicated by a solid line, and the actually measured value P _sensor of the in-cylinder pressure is indicated by a broken line. In the comparative example, as in the first verification, the calculated value P _calc of the in-cylinder pressure is lower by about 1 [MPa] at the maximum near the top dead center than the measured value P _sensor of the in-cylinder pressure by the in-cylinder pressure _sensor . became.

In this example, the value of the initial value correction parameter ΔP was identified by the optimization calculation from the equation (13), and 29 [kPa] was obtained as the value of the initial value correction parameter ΔP. Using the value of the initial value correction parameter ΔP, the initial value P ₀ (= P _S + ΔP) of the in-cylinder pressure is calculated from the above correction equation, and the result of deriving the calculated value P _calc of the in-cylinder pressure is shown in FIG. Indicated. In FIG. 11, the calculated value P _calc of the in-cylinder pressure is indicated by a solid line, and the actually measured value P _sensor of the in-cylinder pressure is indicated by a broken line. As shown in FIG. 11, according to the present embodiment, it can be seen that the calculated value P _calc of the in-cylinder pressure substantially matches the actually measured value P _{sensor of the in-} cylinder pressure.

Further, as a third verification, the results of verification in a two-stage combustion (test condition 3) at a rotational speed of 1200 rpm in an in-line four-cylinder 3000 cc direct injection diesel engine are shown in FIGS. FIG. 12 shows the _apparent heat generation rate ROHR calculated from the value of the identified Wiebe function parameter. In FIG. 12, the heat generation rate ROHR _apparent is shown by a solid line, and the heat generation rate ROHR _sensor is shown by a broken line. FIG. 12 shows that even the heat release rate history of the two-stage combustion can be identified with high accuracy. FIG. 13 shows the result of deriving the calculated value P _calc of the in-cylinder pressure by the comparative example. In FIG. 13, the calculated value P _calc of the in-cylinder pressure is indicated by a solid line, and the actually measured value P _sensor of the in-cylinder pressure is indicated by a broken line. In the comparative example, as in the first verification, the calculated value P _calc of the in-cylinder pressure is lower by about 1 [MPa] at the maximum near the top dead center than the measured value P _sensor of the in-cylinder pressure by the in-cylinder pressure _sensor . became.

In this example, the value of the initial value correction parameter ΔP was identified from the equation (13) by optimization calculation, and 33 [kPa] was obtained as the value of the initial value correction parameter ΔP. Using the value of the initial value correction parameter ΔP, the initial value P ₀ (= P _S + ΔP) of the in-cylinder pressure is calculated from the above correction equation, and the result of deriving the calculated value P _calc of the in-cylinder pressure is shown in FIG. Indicated. In FIG. 14, the calculated value P _calc of the in-cylinder pressure is indicated by a solid line, and the actually measured value P _sensor of the in-cylinder pressure is indicated by a broken line. As shown in FIG. 14, according to the present embodiment, it can be seen that the calculated value P _calc of the in-cylinder pressure substantially matches the measured value P _{sensor of the in-} cylinder pressure.

As described above, in this example, it was confirmed that both the heat generation rate and the in-cylinder pressure having a complicated shape could be reproduced with high accuracy. In addition, we confirmed the effectiveness of this method by identifying the value of the Wiebe function parameter for the heat release rate ROHR _sensor and identifying the initial value correction parameter ΔP for the measured value P _sensor of the in-cylinder pressure.

  Next, an in-vehicle control system including a parameter identification device using the identification method according to the present embodiment will be described with reference to FIGS. 15 to 18. Hereinafter, when the Wiebe function parameter and the initial value correction parameter are not distinguished, they are collectively referred to as “model parameter”. Hereinafter, as an example, it is assumed that the Wiebe function parameter is identified by an identification method that does not take heat loss into consideration. However, the present invention is applicable even when the Wiebe function parameter is identified by an identification method that takes heat loss into account. In this case, a heat loss model for deriving the heat loss according to the operating condition may be used, and the parameters (model parameters) of the heat loss model may be identified.

  FIG. 15 is a diagram illustrating an example of the in-vehicle control system 1 including the parameter identification device 10. In FIG. 15, in addition to the in-vehicle control system 1, the operation data storage unit 2 is also shown.

  The operation data storage unit 2 stores operation data obtained during actual operation of the engine system 4. Note that the operation data is not necessarily data relating to the same individual as the engine system 4, but may be data relating to the same engine system including the same type of internal combustion engine. The operation data is each value obtained during actual operation of the engine system 4, and each value of a predetermined parameter (hereinafter referred to as “operation condition parameter”) representing the operation condition of the internal combustion engine and the measured in-cylinder pressure data are obtained. May include. The operation data can be acquired, for example, by a bench test using an engine dynamometer facility. The operating condition parameter is a parameter that affects the optimum value of the model parameter. That is, the optimum value of the model parameter changes as each value of the operating condition parameter changes. The actually measured in-cylinder pressure data is a set of in-cylinder pressure values for each crank angle, for example, and is collected for each operating condition. For example, FIG. 16 shows an example of operation data. In the example shown in FIG. 16, the operating condition parameters include engine speed, fuel injection amount, fuel injection pressure, oxygen concentration, intake pressure, EGR (Exhaust Gas Recirculation) valve opening, etc., and the fuel injection amount is (In the example shown in FIG. 16, the value is pilot injection, pre-injection, etc.). In the example shown in FIG. 16, each value of each operating condition parameter and measured in-cylinder pressure data are stored in a form associated with the operating condition ID for each operating condition ID (Identification).

  The in-vehicle control system 1 shown in FIG. 15 is mounted on a vehicle. The vehicle is a vehicle that uses an internal combustion engine as a power source, and includes a hybrid vehicle that uses an internal combustion engine and an electric motor as power sources. The type of the internal combustion engine is arbitrary, and may be a diesel engine, a gasoline engine, or the like. Further, the fuel injection method of the gasoline engine is arbitrary, and may be a port injection type, an in-cylinder injection type, or a combination thereof.

  The in-vehicle control system 1 includes an engine system 4 (an example of a vehicle drive device), a sensor group 6, a parameter identification device 10 (an example of an internal combustion engine parameter identification device), and an engine control device 30.

  The engine system 4 may include various actuators (injectors, electronic throttles, starters, etc.) and various members (intake passages, catalysts, etc.) provided in the internal combustion engine.

  The sensor group 6 may include various sensors (crank angle sensor, air flow meter, intake pressure sensor, air-fuel ratio sensor, temperature sensor, etc.) provided in the internal combustion engine. The sensor group 6 need not include an in-cylinder pressure sensor. Installation of the in-cylinder pressure sensor is disadvantageous from the viewpoints of cost, durability, and maintainability.

  The parameter identification device 10 identifies the model parameter by the identification method according to this embodiment described above based on the operation data in the operation data storage unit 2.

  FIG. 17 is a diagram illustrating an example of a hardware configuration of the parameter identification device 10.

  In the example illustrated in FIG. 17, the parameter identification device 10 includes a control unit 101, a main storage unit 102, an auxiliary storage unit 103, a drive device 104, a network I / F unit 106, and an input unit 107.

  The control unit 101 is an arithmetic device that executes a program stored in the main storage unit 102 or the auxiliary storage unit 103, receives data from the input unit 107 or the storage device, calculates, processes, and outputs the data to the storage device or the like. To do.

  The main storage unit 102 is a ROM (Read Only Memory), a RAM (Random Access Memory), or the like. The main storage unit 102 is a storage device that stores or temporarily stores programs and data such as OS (Operating System) and application software which are basic software executed by the control unit 101.

  The auxiliary storage unit 103 is an HDD (Hard Disk Drive) or the like, and is a storage device that stores data related to application software or the like.

  The drive device 104 reads the program from the recording medium 105, for example, a flexible disk, and installs it in the storage device.

  The recording medium 105 stores a predetermined program. The program stored in the recording medium 105 is installed in the parameter identification device 10 via the drive device 104. The installed predetermined program can be executed by the parameter identification device 10.

  The network I / F unit 106 is an interface between the parameter identification device 10 and a peripheral device having a communication function connected via a network constructed by a data transmission path such as a wired and / or wireless line.

  The input unit 107 may be a user interface provided on, for example, a console box or an instrument panel.

  In the example shown in FIG. 17, various processes described below can be realized by causing the parameter identification device 10 to execute a program. It is also possible to record the program on the recording medium 105 and cause the parameter identification device 10 to read the recording medium 105 on which the program is recorded, thereby realizing various processes described below. Note that various types of recording media can be used as the recording medium 105. For example, the recording medium 105 is a recording medium that records information optically, electrically, or magnetically, such as a CD (Compact Disc) -ROM, a flexible disk, or a magneto-optical disk, or information such as a ROM or a flash memory. It may be a semiconductor memory or the like for electrically recording. Note that the recording medium 105 does not include a carrier wave.

  Reference is again made to FIG. The parameter identification device 10 includes an operation data acquisition unit 11, an in-cylinder pressure data acquisition unit 12 (an example of an acquisition unit), a heat generation rate actual value calculation unit 13, and an optimization calculation unit 14. The parameter identification device 10 includes a model parameter storage unit 15 (an example of a relational expression deriving unit), a model parameter storage unit 16 (an example of a second storage unit), and a relational expression storage unit 17.

  The operation data acquisition unit 11, the in-cylinder pressure data acquisition unit 12, the heat generation rate actual measurement value calculation unit 13, the optimization calculation unit 14, and the model parameter storage unit 15 are mainly the control unit 101 shown in FIG. This can be realized by executing one or more programs in the storage unit 102 or the like. Further, the model parameter storage unit 16 and the relational expression storage unit 17 can be realized by the auxiliary storage unit 103 illustrated in FIG. 17, for example.

  The operation data acquisition unit 11 acquires operation data (see FIG. 16) for each operation condition from the operation data storage unit 2.

  The in-cylinder pressure data acquisition unit 12 acquires in-cylinder pressure data among the operation data acquired by the operation data acquisition unit 11.

The actual heat generation rate calculation unit 13 calculates the heat generation rate ROHR _sensor based on the in-cylinder pressure data acquired by the in-cylinder pressure data acquisition unit 12 for each operating condition. Specifically, the actual heat generation rate calculation unit 13 calculates the heat generation rate ROHR _sensor based on the in-cylinder pressure data acquired by the in-cylinder pressure data acquisition unit 12 for each operating condition. The calculation method of the heat release rate ROHR _sensor is as described above.

  The optimization calculation unit 14 identifies a model parameter for each operating condition. The optimization calculation unit 14 includes a Wiebe function parameter identification unit 141 and an initial value correction parameter identification unit 142.

The Wiebe function parameter identification unit 141 executes an optimization calculation using the evaluation function F (for example, see Equation 4) based on the heat generation rate ROHR _sensor calculated by the heat generation rate actual measurement value calculation unit 13 for each operating condition. To do. The Wiebe function parameter identification unit 141 identifies each value (optimum value) of the Wiebe function parameter that minimizes the evaluation function F while changing each value of the Wiebe function parameter.

The initial value correction parameter identification unit 142 evaluates the evaluation function based on each value of the Wiebe function parameter identified by the Wiebe function parameter identification unit 141 and the in-cylinder pressure data acquired by the in-cylinder pressure data acquisition unit 12 for each operating condition. An optimization calculation using F1 (see Equation 13) is executed. At this time, each value of the Wiebe function parameter identified by the Wiebe function parameter identifying unit 141 is used to derive the heat release rate ROHR _calc by the Wiebe function. The derived heat release rate ROHR _calc is used for numerical integration for deriving the calculated value P _calc of the in-cylinder pressure based on the formula (11). The initial value correction parameter identification unit 142 derives the calculated value P _calc of the in-cylinder pressure based on the formula 11 while changing the value of the initial value correction parameter ΔP, and initializes the initial value correction parameter ΔP that minimizes the evaluation function F1. The value of (the optimal value) is identified.

  More specifically, the initial value correction parameter identifying unit 142 includes an initial value setting unit 1420, a heat generation rate deriving unit 1421, an in-cylinder pressure deriving unit 1422, and a parameter identifying unit 1423.

The initial value setting unit 1420 sets an initial value P ₀ of the in-cylinder pressure used for optimization calculation. The in-cylinder pressure initial value P ₀ used for the optimization calculation is set as P ₀ = P _S + ΔP based on the provisional value of the initial value correction parameter ΔP.

The heat release rate deriving unit 1421 calculates the heat release rate ROHR _calc based on each value of the Wiebe function parameter identified by the Wiebe function parameter identifying unit 141. As described above, the heat generation rate deriving unit 1421 performs the period from the combustion start timing θ _soc to the exhaust valve opening timing θ _{EVO in} the identification target period (start timing θ _s to exhaust valve opening timing θ _EVO ) of the initial value correction parameter ΔP. The heat release rate ROHR _calc is calculated only for the period. At this time, the heat generation rate deriving unit 1421 calculates the heat generation rate ROHR _calc based on each value of the Wiebe function parameter identified by the Wiebe function parameter identifying unit 141.

The in-cylinder pressure deriving unit 1422 includes the heat generation rate ROHR _calc calculated by the heat generation rate deriving unit 1421, the initial value P ₀ of the in-cylinder pressure set by the initial value setting unit 1420, and the number in the relational expression storage unit 17. The calculated value P _calc of the in-cylinder pressure is derived based on the equation (11). The method for deriving the calculated value P _calc of the in-cylinder pressure is as described above. Specifically, the cylinder pressure deriving section 1422, with respect to the period from the combustion start timing theta _soc to the exhaust valve opening timing theta _EVO, the heat generation rate ROHR _calc as the heat generation rate ROHR _apparent, the calculated value of the cylinder pressure P _calc is derived. On the other hand, the cylinder pressure deriving section 1422, with respect to the remaining period (start time theta _s ~ combustion start timing theta _soc), a predetermined value (here, 0) as the heat release rate ROHR _apparent, the calculated value of the cylinder pressure P _calc is derived.

The parameter identification unit 1423 evaluates the evaluation function F1 based on the calculated value P _{calc of the} in-cylinder pressure derived by the in-cylinder pressure deriving unit 1422 for each provisional value while changing the provisional value of the initial value correction parameter ΔP. Then, the parameter identification unit 1423 sets the provisional value of the initial value correction parameter ΔP that minimizes the evaluation function F1 as the optimum value (identification value).

  The model parameter storage unit 15 stores each optimum value (an example of identification value information) of the model parameter obtained by the optimization calculation unit 14 for each operation condition in the model parameter storage unit 16 in association with the operation condition ID. In this way, each optimum value of the model parameter is calculated for each operation condition (for each operation condition ID) and stored in the model parameter storage unit 16. FIG. 18 is a diagram conceptually illustrating an example of data in the model parameter storage unit 16. In the example shown in FIG. 18, each optimum value of the model parameter is linked to the data (operating condition parameter) shown in FIG. That is, in the data shown in FIG. 18, each optimum value of the model parameter is associated with each operation condition (each combination of operation condition parameters). In the example shown in FIG. 18, each optimum value of the Wiebe function parameter is obtained for each Wiebe function (that is, for each combustion mode such as combustion by pre-injection or combustion by main injection).

Preferably, the model parameter storage unit 15 is based on data (see FIG. 18) in the model parameter storage unit 16 and represents a relational expression (for example, a first-order equation) representing a relationship between each optimum value of the model parameter and each operation condition. Polynomial) (an example of the second relational expression). Specifically, the model parameter storage unit 15, based on the data shown in FIG. 18, a polynomial modeling information (e.g., the coefficient β ₁ ~β _n described _{below, β1 1 ~β1} value of _n, etc.) (Example of identification value information) is calculated. In this case, the model parameter storage unit 15 may store polynomial modeling information in the model parameter storage unit 16 instead of the data shown in FIG. In this case, compared with the case where the data (map data) shown in FIG. 18 is held, the storage capacity required in the model parameter storage unit 16 can be greatly reduced.

  The polynomial modeling information may be generated as follows, for example. Based on the data in the model parameter storage unit 16 (see FIG. 18), the model parameter storage unit 15 uses the following first-order polynomial to determine the relationship between each optimum value of the Wiebe function parameter and each operating condition. You may approximate.

beta ₀ is the intercept, β ₁ ~β _n is a _coefficient, E 1 to E _n is the operating condition parameters (explanatory variables). n corresponds to the number of explanatory variables. y _j is the value of the Wiebe function parameter, and a polynomial of Equation 14 is used for each Wiebe function parameter. According to the present embodiment, since the relationship between the operating condition and the Wiebe function parameter is maintained over various operating conditions, the relationship can be expressed by a function such as a polynomial. Thereby, it becomes possible to estimate the value of each Wiebe function parameter corresponding to arbitrary operation conditions with high accuracy.

  Similarly, the model parameter storage unit 15 preferably uses the following first-order polynomial based on the data in the model parameter storage unit 16 to determine the optimum value of the initial value correction parameter ΔP and each operating condition. The relationship may be approximated.

.beta.1 ₀ is the intercept, β1 ₁ ~β1 _n is a _coefficient, E 1 to E _n is the operating condition parameters (explanatory variables). n corresponds to the number of explanatory variables. According to the present embodiment, since the relationship between the operating condition and the initial value correction parameter is maintained over various operating conditions, the relationship can be expressed by a function such as a polynomial. As a result, the value of the initial value correction parameter corresponding to an arbitrary operating condition can be estimated with high accuracy.

  In addition, although the formula of Formula 14 and Formula 15 is a 1st order polynomial, other polynomials, such as a 2nd order polynomial, may be used.

  Incidentally, in the data shown in FIG. 18, as described above, each optimum value of the model parameter is associated with each operating condition (each combination of operating condition parameters). Therefore, if data relating to a large number of operating conditions is obtained, the possibility of extracting model parameter values that conform to certain arbitrary operating conditions increases. However, the operating conditions of the internal combustion engine vary greatly depending on combinations of engine speed, air amount, fuel injection pressure, and the like. It is not practical to derive each optimum value of the model parameter over such various operating conditions.

On the other hand, when the polynomial modeling information is obtained using the polynomials such as the above formulas 14 and 15, based on the data shown in FIG. Thus, it is possible to derive each optimum value of the model parameter. That is, the polynomial modeling information may include each value of the coefficients β ₀ to β _n for each Wiebe function parameter and each value of the coefficients β 1 _{0 to} β _{1 n} for the initial value correction parameter. Linkage with each combination of condition parameters is not necessary. Therefore, the data amount of the polynomial modeling information is much smaller than the data shown in FIG. On the other hand, despite the small amount of data, the polynomial modeling information can accurately derive the optimum values of the model parameters over various operating conditions.

  As described above, the model parameter storage unit 16 stores each optimum value of the model parameter in such a manner that each optimum value of the model parameter can be obtained or derived for each operating condition.

  As described above, the relational expression storage unit 17 stores the above formula 11 that is a relational expression (an example of a first relational expression) used for the optimization calculation in the optimization calculation unit 14.

  FIG. 19 is a flowchart illustrating an example of processing executed by the parameter identification device 10. The process shown in FIG. 19 is executed offline, for example. Moreover, the process shown in FIG. 19 is performed for every driving | running condition with respect to the driving | running data regarding the several driving | running condition in the driving | operation data storage part 2, for example. The operating condition is defined by a combination of the above-described operating condition parameter values.

  In step S <b> 1600, the operation data acquisition unit 11 acquires operation data related to one or more operation conditions (operation condition ID) to be calculated this time from the operation data storage unit 2. As described above, the operation data includes each value of the operation condition parameter and in-cylinder pressure data for each operation condition ID (see FIG. 12).

  In step S1601, the operation data acquisition unit 11 selects one specific operation condition in a predetermined order (for example, ascending order of the operation condition ID) from the operation data related to the one or more operation condition IDs acquired in step S1600. Select the operation data related to the ID.

  In step S1602, the in-cylinder pressure data acquisition unit 12 acquires in-cylinder pressure data in the operation data selected in step S1601.

In step S1603, the actual heat generation rate calculation unit 13 calculates the heat generation rate ROHR _sensor for each crank angle based on the in-cylinder pressure data acquired in step S1602.

In step S1604, the Wiebe function parameter identification unit 141 of the optimization calculation unit 14 determines each of the Wiebe function parameters for minimizing the evaluation function F (for example, see Equation 4) based on the heat generation rate ROHR _sensor obtained in step S1603. A value (optimum value) is derived.

  In step S1606, the initial value correction parameter identifying unit 142 of the optimization calculating unit 14 performs initial initialization based on each value (optimum value) of the Wiebe function parameter obtained in step S1604 and the in-cylinder pressure data obtained in step S1602. The optimum value of the value correction parameter ΔP is derived. That is, the initial value correction parameter identifying unit 142 derives the value (optimum value) of the initial value correction parameter that minimizes the evaluation function F1 (see Equation 13).

  In step S1608, the model parameter storage unit 15 stores each value of the model parameter obtained in steps S1604 and S1606 in the model parameter storage unit 16 in association with the current operating condition ID.

  In step S1610, the model parameter storage unit 15 determines whether or not the optimization calculation process has been completed for all of the one or more operating condition IDs acquired in step S1600. If the determination result is “YES”, the process proceeds to step S1612. On the other hand, if the determination result is “NO”, the process shown in FIG. 19 returns to step S1601, the operation data related to a new operation condition ID is selected, and the processes of steps S1604 to S1608 are executed. .

  In step S1612, the model parameter storage unit 15 generates polynomial modeling information based on each value (each value for each operation condition ID) in the model parameter storage unit 16 stored in step S1608. The method for generating the polynomial modeling information is as described above.

  In step S <b> 1614, the model parameter storage unit 15 stores the polynomial modeling information in the model parameter storage unit 16.

  According to the processing shown in FIG. 19, by obtaining operation data over various operation conditions from the operation data storage unit 2, polynomial modeling information capable of deriving highly accurate model parameter values over various operation conditions is obtained. Can do. Thereby, it becomes possible to estimate the value of each model parameter corresponding to arbitrary driving conditions with high accuracy.

  In the process shown in FIG. 19, the identification of the Wiebe function parameter and the identification of the initial value correction parameter are performed simultaneously, but the present invention is not limited to this. That is, the identification of the Wiebe function parameter and the identification of the initial value correction parameter may be executed at different timings.

  Next, referring to FIG. 15 again, the engine control device 30 will be described with reference to FIG.

  The engine control device 30 controls various actuators of the engine system 4. As shown in FIG. 15, the engine control device 30 includes an operating condition determination unit 32, a model function calculation unit 34, an engine torque calculation unit 36 (an example of an in-cylinder pressure calculation unit), and a control value calculation unit 38 (vehicle control). And a relational expression storage unit 39 (an example of a first storage unit). The hardware configuration of the engine control device 30 may be the same as the hardware configuration of the parameter identification device 10 shown in FIG. In the operating condition determination unit 32, the model function calculation unit 34, the engine torque calculation unit 36, and the control value calculation unit 38, the control unit 101 illustrated in FIG. 13 executes one or more programs in the main storage unit 102 and the like. This can be achieved.

  The operating condition determination unit 32 determines the operating condition of the internal combustion engine based on information obtained from the sensor group 6. The operating conditions are used when extracting the optimum values (identified values) of the model parameters corresponding to the operating conditions from the model parameter storage unit 16. When using the above-described polynomial modeling information, the driving condition determination unit 32 derives each value of the above-described driving condition parameter as the determination result of the driving condition based on the information obtained from the sensor group 6.

  The model function calculation unit 34 includes a Wiebe function value calculation unit 341 (an example of a heat generation rate calculation unit), an initial value correction parameter calculation unit 342 (an example of an identification value derivation unit), and an initial value setting unit 343.

The Wiebe function value calculation unit 341 derives the heat release rate ROHR _calc corresponding to the operation condition based on the value of each Wiebe function parameter corresponding to the operation condition. For example, when the above-described polynomial modeling information is stored in the model parameter storage unit 16, the Wiebe function value calculation unit 341 substitutes each value of the operating condition parameter into a polynomial related to each Wiebe function parameter. The value of each Wiebe function parameter is derived. Alternatively, when the map data shown in FIG. 18 is stored in the model parameter storage unit 16, the Wiebe function value calculation unit 341 corresponds to an operation condition that best matches each value of the operation condition parameter from the map data. Get the value of each Wiebe function parameter. Then, the Wiebe function value calculation unit 341 derives the heat release rate ROHR _calc based on the Wiebe function using the derived or acquired values of the respective Wiebe function parameters.

  The initial value correction parameter calculation unit 342 acquires or derives the value of the initial value correction parameter ΔP corresponding to the operating condition. When the above-described polynomial modeling information is stored in the model parameter storage unit 16, the initial value correction parameter calculation unit 342 substitutes each value of the operating condition parameter into the polynomial related to the initial value correction parameter ΔP. Then, the value of the initial value correction parameter ΔP is derived. Alternatively, when the map data shown in FIG. 18 is stored in the model parameter storage unit 16, the initial value correction parameter calculation unit 342 corresponds to the operation condition that best matches each value of the operation condition parameter from the map data. The value of the initial value correction parameter ΔP to be acquired is acquired.

The initial value setting unit 343, the value of the acquired or derived initial value correction parameter ΔP the initial value correction parameter calculator 342, based on the measured value P _S of the in-cylinder pressure, the initial value P ₀ of the in-cylinder pressure To do. As described above, the initial value P ₀ of the in-cylinder pressure can be set as P ₀ = P _S + ΔP. Found P _S of the in-cylinder pressure are the measured values of the in-cylinder pressure at the intake valve closing timing theta _IVC, it is possible to use a detection value of the intake pressure sensor in the intake valve closing timing theta _IVC. However, when the sensor group 6 includes an in-cylinder pressure sensor, the detected value of the in-cylinder pressure sensor at the intake valve closing timing θ _IVC can also be used.

The engine torque calculator 36 calculates the in-cylinder pressure based on the heat release rate ROHR _calc calculated by the Wiebe function value calculator 341 and the value of the initial value correction parameter ΔP calculated by the initial value correction parameter calculator 342. The value P _calc is derived. Then, the engine torque calculation unit 36 calculates the generated torque of the internal combustion engine based on the calculated value P _{calc of the} in-cylinder pressure. For example, the generated torque of the internal combustion engine can be calculated as the sum of torque due to in-cylinder pressure in each cylinder, inertia torque, and the like.

  The control value calculation unit 38 calculates a control target value to be given to the engine system 4 based on the calculated value of the generated torque of the internal combustion engine calculated by the engine torque calculation unit 36. The control target value may be, for example, a target value of the throttle opening, a target value of the fuel injection amount, or the like. The required drive torque may be a driver required drive torque corresponding to the vehicle speed and the accelerator opening, a required drive torque for assisting the driver in driving the vehicle, or the like. The required drive torque for assisting the driver in driving the vehicle is determined based on information from a radar sensor or the like, for example. The required driving torque for supporting the driving of the vehicle by the driver is, for example, the driving torque necessary for traveling at a predetermined vehicle speed, the driving torque necessary for following the preceding vehicle, and the vehicle speed so as not to exceed the limit vehicle speed. It may be a drive torque or the like for limiting.

  The relational expression storage unit 39 stores the above formula (11), which is a relational expression (an example of a first relational expression) used for calculation in the engine torque calculation unit 36.

  FIG. 20 is a flowchart illustrating an example of processing executed by the engine control device 30. The process shown in FIG. 20 is executed, for example, when the engine system 4 is actually operating. Here, as an example, it is assumed that the above-described polynomial modeling information is stored in the model parameter storage unit 16. Further, here, as an example, the processing for one cylinder will be described.

  In step S <b> 1700, the operating condition determination unit 32 acquires sensor information representing the current state of the internal combustion engine from the sensor group 6. The information indicating the current state of the internal combustion engine is, for example, each value of the current operating condition parameter (information indicating the current operating condition of the internal combustion engine) and the current crank angle.

In step S1701, the operating condition determination unit 32 determines whether or not the start time θ _S has arrived based on the current crank angle. In this example, the start timing θ _S is the intake valve closing timing θ _IVC . If the determination result is “YES”, the process proceeds to step S1702, and otherwise, the process proceeds to step S1706.

  In step S1702, the operating condition determination unit 32 determines the current operating condition based on the sensor information obtained in step S1700, thereby deriving each value of the operating condition parameter corresponding to the current operating condition.

  In step S 1703, the Wiebe function value calculation unit 341 of the model function calculation unit 34 stores each Wiebe function parameter corresponding to each value of the current operating condition parameter based on the above-described polynomial modeling information in the model parameter storage unit 16. The value of is derived. Then, the Wiebe function value calculation unit 341 updates the current Wiebe function (that is, the value of each Wiebe function parameter) based on the derived value of each Wiebe function parameter.

  In step S 1704, the initial value correction parameter calculation unit 342 of the model function calculation unit 34 corrects the initial value according to each value of the current operating condition parameter based on the above-described polynomial modeling information in the model parameter storage unit 16. Derives the value of the parameter.

In step S1705, the initial value setting unit 343 of the model function calculation unit 34 calculates the value of the initial value correction parameter ΔP derived in step S1704, the actual measured value P _S of the in-cylinder pressure (the detected value of the intake pressure sensor), and based on, an initial value P ₀ of the in-cylinder pressure (updated). As described above, the initial value P ₀ of the in-cylinder pressure can be set as P ₀ = P _S + ΔP.

In step S1706, Wiebe function value calculation unit 341 derives the current heat generation rate ROHR _calc (heat generation rate ROHR _calc in the current crank angle). When the current crank angle is within the period from the combustion start timing θ _soc to the exhaust valve opening timing θ _EVO , the Wiebe function value calculation unit 341 calculates the current heat generation rate ROHR _calc ( The heat release rate ROHR _{calc at the} current crank angle is derived. On the other hand, if the current crank angle is within the period from the start timing θ _s to the combustion start timing θ _soc , the Wiebe function value calculation unit 341 does not perform any processing and ends step S1706, and proceeds to step S1707. move on.

In step S1707, engine torque calculating section 36, the current and heat generation rate ROHR _calc obtained in step S1706, the initial value _{P 0} of the in-cylinder pressure that was set in step S1704, the number of the relational expression storage section 39 11 Based on the above equation, the current calculated value P _calc of the in-cylinder pressure is derived. The method for deriving the calculated value P _calc of the in-cylinder pressure is as described above. When the current crank angle is within the period from the combustion start timing θ _soc to the exhaust valve opening timing θ _EVO , the engine torque calculation unit 36 uses the heat generation rate ROHR _calc obtained in step S1706 as the heat of Equation 11. Use as the generation rate ROHR (heat generation rate ROHR _apparent ). On the other hand, when the current crank angle is within the period from the start timing θ _s to the combustion start timing θ _soc , the engine torque calculation unit 36 sets the predetermined value (0 in this example) to the heat generation rate ROHR of Formula 11. Used as (heat generation rate ROHR _apparent ).

In step S1708, the engine torque calculation unit 36 calculates the current generated torque of the internal combustion engine based on the calculated value P _{calc of the} in-cylinder pressure obtained in step S1706.

  In step S1710, the control value calculation unit 38 calculates a control target value to be given to the engine system 4 based on the current calculated value of the generated torque of the internal combustion engine calculated by the engine torque calculation unit 36 in step S1708. For example, the control value calculation unit 38 determines the control target value so that the required drive torque is realized based on the difference between the required drive torque and the current calculated value of the generated torque of the internal combustion engine obtained in step S1708. May be.

According to the process shown in FIG. 20, the engine control device 30 can perform feedback control of the engine system 4 based on, for example, the difference between the required driving force and the calculated value of the generated torque of the internal combustion engine based on the Wiebe function. As described above, the accuracy of the calculated value of the generated torque of the internal combustion engine based on the Wiebe function is increased because the accuracy of the calculated value P _calc of the in-cylinder pressure is high by using the initial value correction parameter ΔP as described above. For this reason, the engine system 4 can be accurately controlled using a highly accurate calculated value of the torque generated by the internal combustion engine. Thereby, for example, it is not necessary to inject fuel excessively into the cylinder, engine performance is improved, and fuel consumption and drivability are improved. In this way, the data (data in the model parameter storage unit 16) obtained by the parameter identification device 10 can be effectively used for improving the performance of the engine control system.

In FIG. 20, the processing for one cylinder has been described. When the internal combustion engine has a plurality of cylinders, the process shown in FIG. 20 may be executed for each cylinder. In this case, in step S1708, the engine torque calculation unit 36 can calculate the current generated torque of the internal combustion engine based on the calculated value P _{calc of the} in-cylinder pressure relating to all the cylinders. Further, even when the internal combustion engine has a plurality of cylinders, the operating conditions can be common, and therefore Steps S1702 to S1705 may be executed only for one specific cylinder.

  Next, with reference to FIG. 21, the alternative example with respect to the vehicle-mounted control system 1 mentioned above is demonstrated.

  FIG. 21 is a diagram illustrating another example of the in-vehicle control system including the parameter identification device.

  The in-vehicle control system 1A shown in FIG. 21 is different from the in-vehicle control system 1 shown in FIG. 15 in that the operation data acquisition unit 11 is omitted. Further, in the in-vehicle control system 1A shown in FIG. 21, the parameter identification device 10 is replaced with the parameter identification device 10A, and the sensor group 6 is replaced with the sensor group 6A, compared to the in-vehicle control system 1 shown in FIG. Different points. The constituent elements of the in-vehicle control system 1A shown in FIG. 21 that may be the same as those in the in-vehicle control system 1 shown in FIG. 15 are given the same reference numerals in FIG.

  The sensor group 6A is different from the above-described sensor group 6 that does not need to include an in-cylinder pressure sensor in that it includes an in-cylinder pressure sensor.

  The parameter identification device 10A is different from the parameter identification device 10 in that the in-cylinder pressure data acquisition unit 12 is replaced with the in-cylinder pressure data acquisition unit 12A. The in-cylinder pressure data acquisition unit 12A has the same data as the in-cylinder pressure data acquisition unit 12, but the same data is obtained from the operation data storage unit 2 in that the same data is acquired from the sensor group 6A (in-cylinder pressure sensor). The in-cylinder pressure data acquisition unit 12 that acquires

  According to the in-vehicle control system 1A shown in FIG. 21, since the sensor group 6A includes the in-cylinder pressure sensor, the process shown in FIG. 19 can be executed even in the vehicle mounted state (that is, the state after the vehicle is shipped). That is, according to the in-vehicle control system 1A shown in FIG. 21, the data (including the case of polynomial modeling information) in the model parameter storage unit 16 can be updated regularly or irregularly in the vehicle mounted state. Thereby, even when there are individual differences in the characteristics of the internal combustion engine, the model parameters can be corrected according to the individual differences. Even when the characteristics of the internal combustion engine change with time, the model parameters can be updated.

  The engine control device 30 shown in FIGS. 15 and 21 is mounted on the in-vehicle control systems 1 and 1A together with all the components of the parameter identification devices 10 and 10A, but is not limited thereto. For example, the engine control device 30 may be implemented in the in-vehicle control systems 1 and 1A in a manner that includes the model parameter storage unit 16 that is a part of the parameter identification devices 10 and 10A. In other words, the in-vehicle control systems 1 and 1A may be realized in a manner that does not include components other than the model parameter storage unit 16 among the components of the parameter identification devices 10 and 10A. In this case, the above-described data may be stored in the model parameter storage unit 16 in advance (for example, before shipment from the factory).

  In the in-vehicle control systems 1 and 1A shown in FIGS. 15 and 21, the engine system 4 is an example of a vehicle drive device to be controlled, but is not limited thereto. For example, the vehicle drive device to be controlled may include a transmission, an electric motor, a clutch and the like in addition to or instead of the engine system 4.

  Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes can be made within the scope described in the claims. It is also possible to combine all or a plurality of the components of the above-described embodiments.

For example, in the above-described embodiment, the value of the in-cylinder pressure initial value correction parameter ΔP is identified, but is not limited thereto. For example, the initial value P ₀ of the in-cylinder pressure may be identified. Specifically, the value of the initial value P ₀ that minimizes the evaluation function F1 (see Equation 13) may be identified by optimization calculation. In this case, likewise, the value of the initial value P ₀ is identified for each operating condition. Then, the identification value of the initial value P ₀ for each operating condition is stored in the model parameter storage unit 16 in a manner that can be acquired or derived for each operating condition.

  Moreover, in the Example mentioned above, although the vehicle provided with an engine was made into an object as an example, as long as an engine is provided, an object is arbitrary. For example, the target may be a railway vehicle equipped with an engine, a ship equipped with an engine, a construction machine equipped with an engine, a motorcycle equipped with an engine (a type of vehicle), an aircraft equipped with an engine, a helicopter equipped with an engine, and the like.

Further, in the above-described embodiment, the specific differential equation expressed by Equation 11 is used to derive the calculated value P _calc of the in-cylinder pressure, but even if an equation equivalent to the specific differential equation expressed by Equation 11 is used. Good. For example, as an equivalent formula, the formula of Formula 5 may be used. Further, as an equivalent expression, for the differential equation shown in Equation 11, the general solution of the differential equation shown in Equation 11 (generally regarded as a first-order differential equation related to P) with the Wiebe function as f (θ), for example, is used. It may be an expression derived by obtaining. Also in this case, identification of the value of the initial value correction parameter ΔP still involves numerical integration of f (θ).

、ここで、ROHRは前記熱発生率、Ｐは前記筒内圧、Ｖは筒内体積、γは比熱比、θはクランク角度である、付記１〜８のうちのいずれか１項に記載の内燃機関パラメータ同定装置。
［付記１０］
前記パラメータ同定部は、内燃機関の複数の運転条件に対して、運転条件毎に、前記初期値パラメータの値を同定する、付記１〜９のうちのいずれか１項に記載の内燃機関パラメータ同定装置。
［付記１１］
前記運転条件毎に同定した前記初期値パラメータの値と、前記運転条件を表す複数の運転条件パラメータの各値との第２関係式を導出する関係式導出部を更に含む、付記１０に記載の内燃機関パラメータ同定装置。
［付記１２］
内燃機関を備える車両に搭載される車載制御システムであって、
内燃機関の気筒内の燃焼による熱発生率と筒内圧との第１関係式を格納する第１記憶部と、
初期値パラメータの同定値を表す情報又は該同定値を導出できる情報である同定値情報を格納する第２記憶部と、
Wiebe関数に基づいて、前記熱発生率の算出値を導出する熱発生率算出部と、
前記第２記憶部に格納された前記同定値情報に基づいて、前記同定値を取得又は導出する同定値導出部と、
同定値導出部により取得又は導出された前記同定値に基づいて、前記筒内圧の初期値を設定する初期値設定部と、
前記第１関係式と、前記初期値と、前記熱発生率の算出値とに基づいて、前記筒内圧の算出値を導出する筒内圧算出部とを含む、車載制御システム。
［付記１３］
内燃機関の運転条件を判断する運転条件判断部を更に含み、
前記同定値導出部は、前記運転条件に応じた前記同定値を導出する、付記１２に記載の車載制御システム。
［付記１４］
前記同定値情報は、前記運転条件を表す複数の運転条件パラメータと、前記同定値との第２関係式を含み、
前記同定値導出部は、前記第２関係式に基づいて、前記運転条件に応じた前記同定値を導出する、付記１３に記載の車載制御システム。
［付記１５］
前記初期値設定部は、吸気圧センサ又は筒内圧センサから得られる吸気圧の検出値に前記同定値を加算して得られる値を、前記初期値として設定する、付記１２〜１４のうちのいずれか１項に記載の車載制御システム。
［付記１６］
前記筒内圧算出部は、燃焼開始時期以後の前記筒内圧の算出値については、前記熱発生率の算出値に基づいて導出し、燃焼開始時期よりも前の前記筒内圧の算出値については、前記熱発生率の算出値に代わる所定値に基づいて導出する、付記１２〜１５のうちのいずれか１項に記載の車載制御システム。
［付記１７］
前記同定値情報は、前記筒内圧の実測値と前記筒内圧の算出値との間の差に係る評価値を最小化するように前記初期値パラメータの値を同定して得られる結果に基づいて、生成される、付記１２〜１６のうちのいずれか１項に記載の車載制御システム。
［付記１８］
前記筒内圧算出部により導出された前記筒内圧の算出値に基づいて、車両を制御する車両制御部を更に含む、付記１２〜１７のうちのいずれか１項に記載の車載制御システム。
［付記１９］
内燃機関の気筒内の燃焼による熱発生率と内燃機関の筒内圧との第１関係式を取得し、
前記筒内圧の実測値を取得し、
Wiebe関数に基づいて、前記熱発生率の算出値を導出し、
初期値パラメータの値に基づいて、前記筒内圧の初期値を設定し、
前記第１関係式と、前記熱発生率の算出値と、前記初期値とを用いて、前記筒内圧の算出値を導出し、
前記筒内圧の実測値と前記筒内圧の算出値との関係に基づいて、前記初期値パラメータの値を同定することを含む、コンピュータにより実行される内燃機関パラメータ同定方法。
［付記２０］
内燃機関の気筒内の燃焼による熱発生率と内燃機関の筒内圧との第１関係式を取得し、
前記筒内圧の実測値を取得し、
Wiebe関数に基づいて、前記熱発生率の算出値を導出し、
初期値パラメータの値に基づいて、前記筒内圧の初期値を設定し、
前記第１関係式と、前記熱発生率の算出値と、前記初期値とを用いて、前記筒内圧の算出値を導出し、
前記筒内圧の実測値と前記筒内圧の算出値との関係に基づいて、前記初期値パラメータの値を同定する、
処理をコンピュータに実行させるプログラム。 In addition, the following additional remarks are disclosed regarding the above Example.
[Appendix 1]
A relational expression storage unit for storing a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure of the internal combustion engine;
An acquisition unit for acquiring an actual measurement value of the in-cylinder pressure;
Based on a Wiebe function, a heat generation rate deriving unit for deriving a calculated value of the heat generation rate,
An initial value setting unit for setting an initial value of the in-cylinder pressure based on a value of an initial value parameter;
An in-cylinder pressure deriving unit for deriving the calculated value of the in-cylinder pressure based on the first relational expression, the calculated value of the heat generation rate, and the initial value;
An internal combustion engine parameter identification device comprising: a parameter identification unit that identifies a value of the initial value parameter based on a relationship between an actually measured value of the in-cylinder pressure and a calculated value of the in-cylinder pressure.
[Appendix 2]
The parameter identification unit identifies the value of the initial value parameter such that an evaluation value related to an error in the calculated value of the in-cylinder pressure with respect to the measured value of the in-cylinder pressure over the identification target period is minimized. The internal combustion engine parameter identification device.
[Appendix 3]
The internal combustion engine according to appendix 2, wherein the identification target period is from a start timing after the intake valve closing timing and before the combustion start timing to an end timing after the combustion start timing and before the exhaust valve opening timing. Parameter identification device.
[Appendix 4]
The start timing is an intake valve closing timing, and the end timing is an exhaust valve opening timing,
The internal combustion engine parameter identification device according to appendix 3, wherein the evaluation value is a sum of squares of the error.
[Appendix 5]
The in-cylinder pressure deriving unit derives a calculated value of the in-cylinder pressure in a period after the combustion start timing in the identification target period based on the calculated value of the heat generation rate, and out of the identification target period The internal combustion engine parameter identification device according to appendix 4, wherein the calculated value of the in-cylinder pressure within a period prior to the combustion start time is derived based on a predetermined value instead of the calculated value of the heat generation rate.
[Appendix 6]
The initial value setting unit sets, as the initial value, a value obtained by adding the value of the initial value parameter to the actually measured value of the in-cylinder pressure at the start time,
The in-cylinder pressure deriving unit derives a calculated value of the in-cylinder pressure by performing an integration operation according to the first relational expression in an integration interval starting from the start time,
The internal combustion engine parameter identification device according to any one of appendices 3 to 5, wherein the in-cylinder pressure deriving unit uses the initial value as the value of the in-cylinder pressure at the start timing in the integral calculation.
[Appendix 7]
The internal combustion engine parameter identification device according to any one of supplementary notes 1 to 6, wherein a value of each parameter of the Wiebe function is identified based on an actually measured value of the in-cylinder pressure.
[Appendix 8]
The first relational expression includes any one of appendices 1 to 7 including a function expression of the heat generation rate that changes according to a crank angle and a function expression of an in-cylinder volume that changes according to the crank angle. The internal combustion engine parameter identification device according to the item.
[Appendix 9]
The first relational expression is the following differential equation related to the in-cylinder pressure or an expression equivalent to the differential equation.

Here, ROHR is the heat generation rate, P is the in-cylinder pressure, V is the in-cylinder volume, γ is the specific heat ratio, and θ is the crank angle. Engine parameter identification device.
[Appendix 10]
The internal combustion engine parameter identification according to any one of appendices 1 to 9, wherein the parameter identification unit identifies a value of the initial value parameter for each operation condition with respect to a plurality of operation conditions of the internal combustion engine. apparatus.
[Appendix 11]
The relational value deriving unit for deriving a second relational expression between the value of the initial value parameter identified for each operating condition and each value of the plurality of operating condition parameters representing the operating condition, further comprising: Internal combustion engine parameter identification device.
[Appendix 12]
An in-vehicle control system mounted on a vehicle equipped with an internal combustion engine,
A first storage for storing a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure;
A second storage unit that stores identification value information that is information representing an identification value of an initial value parameter or information from which the identification value can be derived;
Based on a Wiebe function, a heat generation rate calculation unit for deriving a calculated value of the heat generation rate,
An identification value deriving unit that acquires or derives the identification value based on the identification value information stored in the second storage unit;
Based on the identification value acquired or derived by the identification value deriving unit, an initial value setting unit that sets an initial value of the in-cylinder pressure;
An in-vehicle control system including an in-cylinder pressure calculation unit that derives a calculated value of the in-cylinder pressure based on the first relational expression, the initial value, and the calculated value of the heat generation rate.
[Appendix 13]
An operating condition determining unit for determining an operating condition of the internal combustion engine;
The in-vehicle control system according to appendix 12, wherein the identification value deriving unit derives the identification value according to the operating condition.
[Appendix 14]
The identification value information includes a plurality of operation condition parameters representing the operation conditions and a second relational expression between the identification values,
The in-vehicle control system according to supplementary note 13, wherein the identification value deriving unit derives the identification value according to the operation condition based on the second relational expression.
[Appendix 15]
The initial value setting unit sets, as the initial value, a value obtained by adding the identification value to an intake pressure detection value obtained from an intake pressure sensor or an in-cylinder pressure sensor. The in-vehicle control system according to claim 1.
[Appendix 16]
The in-cylinder pressure calculation unit derives the calculated value of the in-cylinder pressure after the combustion start timing based on the calculated value of the heat generation rate, and for the calculated value of the in-cylinder pressure before the combustion start timing, The in-vehicle control system according to any one of appendices 12 to 15, which is derived based on a predetermined value instead of the calculated value of the heat generation rate.
[Appendix 17]
The identification value information is based on a result obtained by identifying a value of the initial value parameter so as to minimize an evaluation value related to a difference between the actually measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure. The on-vehicle control system according to any one of supplementary notes 12 to 16, which is generated.
[Appendix 18]
The in-vehicle control system according to any one of appendices 12 to 17, further including a vehicle control unit that controls the vehicle based on the calculated value of the in-cylinder pressure derived by the in-cylinder pressure calculation unit.
[Appendix 19]
Obtaining a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure of the internal combustion engine;
Obtain the actual measured value of the in-cylinder pressure,
Based on the Wiebe function, the calculated value of the heat release rate is derived,
Based on the value of the initial value parameter, set the initial value of the in-cylinder pressure,
Using the first relational expression, the calculated value of the heat generation rate, and the initial value, the calculated value of the in-cylinder pressure is derived,
An internal combustion engine parameter identification method executed by a computer, comprising identifying a value of the initial value parameter based on a relationship between an actually measured value of the in-cylinder pressure and a calculated value of the in-cylinder pressure.
[Appendix 20]
Obtaining a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure of the internal combustion engine;
Obtain the actual measured value of the in-cylinder pressure,
Based on the Wiebe function, the calculated value of the heat release rate is derived,
Based on the value of the initial value parameter, set the initial value of the in-cylinder pressure,
Using the first relational expression, the calculated value of the heat generation rate, and the initial value, the calculated value of the in-cylinder pressure is derived,
Based on the relationship between the measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure, the value of the initial value parameter is identified.
A program that causes a computer to execute processing.

DESCRIPTION OF SYMBOLS 1, 1A Vehicle-mounted control system 2 Operation data storage part 4 Engine system 6, 6A Sensor group 10, 10A Parameter identification apparatus 11 Operation data acquisition part 12, 12A In-cylinder pressure data acquisition part 13 Heat release rate measured value calculation part 14 Optimization calculation Unit 15 Model parameter storage unit 16 Model parameter storage unit 17 Relational expression storage unit 30 Engine control device 32 Operating condition determination unit 34 Model function calculation unit 36 Engine torque calculation unit 38 Control value calculation unit 39 Relational expression storage unit 141 Function parameter identification unit 142 Initial value correction parameter identification unit 341 Wiebe function value calculation unit 342 Initial value correction parameter calculation unit 343 Initial value setting unit 1420 Initial value setting unit 1421 Heat release rate deriving unit 1422 In-cylinder pressure deriving unit 1423 Parameter identifying unit

Claims (11)

A relational expression storage unit for storing a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure of the internal combustion engine;
An acquisition unit for acquiring an actual measurement value of the in-cylinder pressure;
Based on a Wiebe function, a heat generation rate deriving unit for deriving a calculated value of the heat generation rate,
An initial value setting unit for setting an initial value of the in-cylinder pressure based on a value of an initial value parameter;
An in-cylinder pressure deriving unit for deriving the calculated value of the in-cylinder pressure based on the first relational expression, the calculated value of the heat generation rate, and the initial value;
An internal combustion engine parameter identification device comprising: a parameter identification unit that identifies a value of the initial value parameter based on a relationship between an actually measured value of the in-cylinder pressure and a calculated value of the in-cylinder pressure.   The parameter identification unit identifies the value of the initial value parameter such that an evaluation value related to an error in a calculated value of the in-cylinder pressure with respect to an actually measured value of the in-cylinder pressure over an identification target period is minimized. The internal combustion engine parameter identification device described.   3. The internal combustion engine according to claim 2, wherein the identification target period is after an intake valve closing timing and before a combustion start timing to an end timing after the combustion start timing and before an exhaust valve opening timing. Engine parameter identification device. The start timing is an intake valve closing timing, and the end timing is an exhaust valve opening timing,
The internal combustion engine parameter identification device according to claim 3, wherein the evaluation value is a sum of squares of the error. The initial value setting unit sets, as the initial value, a value obtained by adding the value of the initial value parameter to the actually measured value of the in-cylinder pressure at the start time,
The in-cylinder pressure deriving unit derives a calculated value of the in-cylinder pressure by performing an integration operation according to the first relational expression in an integration interval starting from the start time,
5. The internal combustion engine parameter identification device according to claim 3, wherein the in-cylinder pressure deriving unit uses the initial value as the value of the in-cylinder pressure at the start timing in the integration calculation. The first relational expression is the following differential equation related to the in-cylinder pressure or an expression equivalent to the differential equation.

Here, ROHR is the heat generation rate, P is the in-cylinder pressure, V is the in-cylinder volume, γ is a specific heat ratio, and θ is a crank angle. Internal combustion engine parameter identification device.   The internal combustion engine parameter according to any one of claims 1 to 6, wherein the parameter identification unit identifies a value of the initial value parameter for each operation condition with respect to a plurality of operation conditions of the internal combustion engine. Identification device.   The relational expression deriving unit for deriving a second relational expression between the value of the initial value parameter identified for each operating condition and each value of the plurality of operating condition parameters representing the operating condition. The internal combustion engine parameter identification device. An in-vehicle control system mounted on a vehicle equipped with an internal combustion engine,
A first storage for storing a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure;
A second storage unit that stores identification value information that is information representing an identification value of an initial value parameter or information from which the identification value can be derived;
Based on a Wiebe function, a heat generation rate calculation unit for deriving a calculated value of the heat generation rate,
An identification value deriving unit that acquires or derives the identification value based on the identification value information stored in the second storage unit;
Based on the identification value acquired or derived by the identification value deriving unit, an initial value setting unit that sets an initial value of the in-cylinder pressure;
An in-vehicle control system including an in-cylinder pressure calculation unit that derives a calculated value of the in-cylinder pressure based on the first relational expression, the initial value, and the calculated value of the heat generation rate. An operating condition determining unit for determining an operating condition of the internal combustion engine;
The in-vehicle control system according to claim 9, wherein the identification value deriving unit derives the identification value according to the operation condition. Obtaining a first relational expression between a heat generation rate due to combustion in a cylinder of the internal combustion engine and an in-cylinder pressure of the internal combustion engine;
Obtain the actual measured value of the in-cylinder pressure,
Based on the Wiebe function, the calculated value of the heat release rate is derived,
Based on the value of the initial value parameter, set the initial value of the in-cylinder pressure,
Using the first relational expression, the calculated value of the heat generation rate, and the initial value, the calculated value of the in-cylinder pressure is derived,
An internal combustion engine parameter identification method executed by a computer, comprising identifying a value of the initial value parameter based on a relationship between an actually measured value of the in-cylinder pressure and a calculated value of the in-cylinder pressure.

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