JP6834422B2 - Internal combustion engine parameter identification device and internal combustion engine parameter identification method - Google Patents

Description

The present disclosure relates to an internal combustion engine parameter identification device及beauty engine parameter identification method.

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

JP-A-2007-239524 Japanese Unexamined Patent Publication No. 2008-255932

However, in the prior art, it is difficult to improve the accuracy of the calculated value of the in-cylinder pressure that can be derived by using the Wiebe function. This is because the Wiebe function cannot reproduce the heat generation rate in the period before the combustion start time (that is, the period after the intake valve closing time and before the combustion start time).

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

On one side, a relational expression storage unit that stores the first relational expression between the heat generation rate due to combustion in the cylinder of the internal combustion engine and the cylinder pressure of the internal combustion engine, and
An acquisition unit that acquires the measured value of the in-cylinder pressure, and
A heat generation rate actual measurement value calculation unit that calculates the actual measurement value of the heat generation rate based on the actual measurement value of the in-cylinder pressure,
Based on the relationship between the measured value of the heat generation rate and the heat generation rate obtained from the Wiebe function, the parameters of the Wiebe function are set for the first identification target period from the combustion start time or fuel injection time to the exhaust valve opening time. Wiebe function parameter identification part to identify,
A heat generation rate deriving unit that derives a calculated value of the heat generation rate based on the parameters of the Wiebe function identified by the Wiebe function parameter identification unit.
The measured values of the cylinder pressure in the earlier start timing the combustion start timing a intake valve closing timing after, based on the value of the initial value correction parameter of the cylinder pressure, the cylinder pressure at the start timing The initial value setting section that sets the initial value and
An in-cylinder pressure deriving unit that derives 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.
A parameter identification unit that identifies the value of the initial value correction parameter during the second identification target period from the start time to the exhaust valve opening time based on the relationship between the measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure. An internal combustion engine parameter identification device including and is provided.

On one aspect, according to the present invention, it is possible to improve the accuracy of the calculated value of the in-cylinder pressure derived by 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 generation rate. It is a figure which shows the relationship between the Wiebe function and the heat generation rate in the case of three-stage injection. It is explanatory drawing of the identification target period of a Wiebe function parameter. It is explanatory drawing of the identification target period of the initial value correction parameter. It is explanatory drawing of the problem in the comparative example. It is explanatory drawing of the reproduction characteristic of the heat generation rate by a Wiebe function. It is explanatory drawing of the verification result under test condition 1. It is explanatory drawing of the verification result by test condition 1. It is explanatory drawing of the verification result by test condition 1. It is explanatory drawing of the verification result by test condition 2. It is explanatory drawing of the verification result by test condition 2. It is explanatory drawing of the verification result by test condition 2. It is explanatory drawing of the verification result under test condition 3. It is explanatory drawing of the verification result under test condition 3. It is explanatory drawing of the verification result under test condition 3. It is a figure which shows an example of an in-vehicle control system including a parameter identification device. It is a figure which shows an example of the operation data. It is a figure which shows an example of the hardware configuration of a parameter identification apparatus. It is a figure which conceptually shows an example of the data in a model parameter storage part. It is a flowchart which shows an example of the process executed by a parameter identification apparatus. It is a flowchart which shows an example of the process executed by an engine control device. It is a figure which shows another example of an in-vehicle control system including a parameter identification apparatus.

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

Here, first, the basic matters 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 the heat generation pattern (combustion waveform). _{Specifically, the Wiebe function is a function that approximates the profile of the combustion rate x b} 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 represent the shape index, θ _soc represents the combustion start time (Start of Combustion), and Δθ represents the combustion period, respectively. These 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 x _b . The horizontal axis is the crank angle θ, and the vertical axis is the combustion rate x _b . _{Using these four Wiebe function parameters, the calculated value ROHR calc} of the heat generation rate (Rate of Heat Release) in the cylinder (hereinafter, also simply referred to as "heat generation rate ROHR _calc ") is expressed as the following equation. To.

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 amount of heat generated in the cylinder. As the value of the total heat generation amount Q _b, a value calculated based on the fuel injection amount or the like may be used.
At the same time, _{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. In FIG. 1B, the total amount of heat generated HR (Θ) when the crank angle θ = Θ is shown in the hatched range.

Here, in the equation of Equation 2, assuming that the values of the Wiebe function parameters to be identified are the values _{of the four Wiebe function parameters of a, m, θ soc} , and Δθ, the values of the Wiebe function parameters to be identified are 4. It is an individual. The value of the combustion ratio xf may also be included in the value of the Wiebe function parameter to be identified. Further, for example, the Wiebe function parameter a may be a fixed value such as 6.9. Hereinafter, each value of these Wiebe function parameters a, m, θsoc, and Δθ will be referred to as an a value, m value, θ _soc value, and Δθ value, respectively.

The values of each Wiebe function parameter, such as the a, m, θ _soc , and Δθ values, are identified so that, for example, the error in 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 the error squares 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 the interior point method, the sequential quadrangle 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). The heat generation rate ROHR _calc is the heat generation rate obtained from the Wiebe function. Σ represents the integration. In addition, θ _EVO represents the exhaust valve opening time (Exhaust valve opening). The start time of the identification target period of the Wiebe function parameter is the combustion start time θ _soc , but the measured in-cylinder pressure data used for identification is _{the data from the time before the combustion start time θ soc} (for example, fuel injection time θ _SOI). Data from). FIG. 3A is an explanatory diagram of the identification target period of the Wiebe function parameter. In FIG. 3A, the identification target period of the Wiebe function parameter is indicated by the period R1. Similar to FIG. 2, 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. In this case, the identification target period of the Wiebe function parameter is indicated by the period R2, and is from the combustion start time θ _soc to the exhaust valve opening time θ _EVO .

The heat generation 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 The ROHR _sensor represents the 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, as the value of γ, a known value determined based on the composition of the combustion gas or the like may be used. For the calculation of the heat generation rate ROHR _sensor, the value of the in-cylinder pressure P based on the actually measured in-cylinder pressure data is used. As each value of the in-cylinder volume V and its rate of change dV / dθ, a value geometrically determined according to the crank angle θ may be used.

However, instead of the apparent heat generation rate ROHR _sensor , the true heat generation rate ROHR _true corrected in consideration of heat loss may be used for the identification of the Wiebe function parameter. 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 of Equation 5. That is, it is as follows.
ROHR _true = ROHR _sensor + HL _real
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) according to the crank angle can be derived by an empirical formula for predicting the average heat transfer coefficient on the cylinder wall surface using the actually measured 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 equation of Equation 6 represents the heat transfer coefficient to the cylinder wall surface, where C is the 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 equation of Equation 6, T is the cylinder gas temperature, 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, which is substantially equivalent to the crank angle θ. As the value of P, a value based on the measured in-cylinder pressure data (value corresponding to the crank angle θ) is used.

In the following, when identifying the Wiebe function parameter, the _{method of using the heat generation rate ROHR true} corrected in consideration of heat loss instead _{of the heat generation rate ROHR sensor} is particularly expressed as "adding heat loss. Identification method ". On the other hand, a _{method using a heat generation rate ROHR sensor} when identifying Wiebe function parameters is referred to as an "identification method that does not take heat loss into consideration". According to the identification method that takes heat loss into consideration, it is possible to accurately reproduce the _{heat generation rate ROHR sensor that represents the apparent heat generation rate based on the Wiebe function.} This is because, as shown in FIG. 1B, Equation 2, etc., the Wiebe function cannot take a negative value, and the region where the apparent heat generation rate is negative (that is, the region where heat loss larger 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 multi-stage injection such as a diesel engine is a superposition of the heat generation rates of each stage, and 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 the case of a diesel engine that performs three-stage injection. FIG. 2 shows a combustion waveform related to combustion by pre-injection by the first stage injection, a combustion waveform related to combustion by the second stage main injection, and first combustion and second combustion of combustion by the third stage after injection. Each combustion waveform related to combustion (diffusion combustion) and a composite waveform of these are shown. In FIG. 2, θ _SOC1 represents the combustion start time related to the combustion by the first-stage pre-injection.

For example, in the case of 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 shown below. 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 the combustion ratio. The equation of equation 7 corresponds to the equation of the equation of equation 2 combined with N + 1 in the form of multiplying the combustion ratio xf. That is, the equation of equation 7 corresponds to an equation in which N + 1 combinations of the Wiebe functions related to i = k (where k is an arbitrary number of 1 to N + 1) are multiplied by the combustion ratio xf. Hereinafter, when a function that combines a plurality of Wiebe functions is particularly referred to, it is referred to as a "combination Wiebe function".

According to such a modeling method using the combination Wiebe function, highly accurate 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 modes having different combustion types in one cycle. The combustion modes having 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. Since the heat generation rate in the case of multi-stage injection such as the latest diesel engine is a superposition of the heat generation rates of each stage, a modeling method using the combined Wiebe function is useful. However, not only in diesel engines but also in gasoline engines and the like, there may be a plurality of combustion modes having different combustion types in one cycle. Therefore, the modeling method using the combinatorial Wiebe function is also applicable to other engines such as gasoline engines.

Here, assuming that 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 in the equation of Equation 7, since there are N + 1 Wiebe functions, The value of the Wiebe function parameter to be identified is 4 × (N + 1). The value of the combustion ratio xf may also be included in the value of the Wiebe function parameter to be identified. Further, 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 in the evaluation formula (evaluation function) for identifying the value of the Wiebe function parameter. In this case, the heat generation rate ROHR _calc is calculated based on the equation of Equation 7. Alternatively, in order to improve the accuracy of parameter identification, the sum of the error squares of the heat generation amount HR, the difference in the m value between the Wiebe functions related to each of the two combustion modes with different combustion types, and the Δθ value between the Wiebe functions Differences and the like may be included. For example, in this case, the evaluation function F may be, for example, as follows.

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

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

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 several tens, the second term in the curly braces is the evaluation value related 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 with a value that minimizes the evaluation function F. At this time, the values of the Wiebe function parameters that minimize the evaluation function F may be derived by optimization calculation using the interior point method, the sequential quadrangle method, or the like. In addition, other constraints may be added during the optimization calculation. Other constraint conditions are, for example, that _{the sum of the combustion ratios xf i} is about 1, and that the combustion ratio xf of the Wiebe function related to the main combustion is larger than the combustion ratio xf of the Wiebe function related to 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 is identified as described above will be described. Although the combination Wiebe function has been described above, 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 equation (an example of the first relational expression). The form of the equation of Equation 11 is obtained by converting the equation of Equation 5 into a differential equation relating to the 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. Combustion start time θ The _apparent heat generation rate after _SOC is calculated based on the Wiebe function. At this time, when the Wiebe function parameter is identified by the identification method in consideration of heat loss, the heat generation rate ROHR _appearance may be calculated as ROHR _appearance = ROHR _calc −HL _actual. Further, when the Wiebe function parameter is identified by an identification method that does not take heat loss into consideration, the heat generation rate ROHR _appearance may be ROHR _appearance = ROHR _calc.

On the other hand, a predetermined value is used for the _apparent heat generation rate ROHR in the period before the _{combustion start time θ SOC.} The predetermined value may _{be a value that is variable over a period prior to the combustion start time θ SOC} , or may be a constant constant value 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 time θ _soc is substantially 0 (see part X in FIG. 5). Alternatively, when the Wiebe function parameter is identified by an identification method that takes heat loss into account, -HL _fruit may be used as the predetermined value (that is, ROHR _apparent = ROHR _calc −HL _real = 0-HL). _Real = -HL _real ). 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 prior to the _{combustion start time θ SOC.} It is assumed to be 0.

Here, numerical integration is used to derive _{the calculated value P calc} of the in-cylinder pressure from the equation of Equation 11. _{For example, the derivation of the calculated value P calc} of the in-cylinder pressure from the equation of Equation 11 _{involves the apparent} numerical integration of the heat generation rate ROHR. In order to perform the numerical integration according to the equation of Equation 11, it is _{necessary to set the initial value P 0} (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 time θ s (hereinafter, simply referred to as “start time θ _S ”) after the intake valve closing time θ _{IVC and before the combustion start time θ SOC.} Represents a value. The start time θ _S is arbitrary as long as it is after the intake valve closing time θ _{IVC and} before the combustion start time θ _SOC , but it is preferably the intake valve closing time θ _IVC that can be easily specified. In the following, as an example, it is assumed that the start time θ _S = the intake valve closing time θ _{IV C.}

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

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 an actually measured value of the in-cylinder pressure at the start time θ _S. ΔP is an initial value correction parameter (an example of the initial value parameter) of the in-cylinder pressure, and is a positive or negative value. As described above, 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 time θ _S. That is, in this embodiment, _{the measured value P S} of the in-cylinder pressure at the start time θ _{S is not used as it is as the initial value P 0} , but the initial value correction parameter ΔP is added (corrected by the initial value correction parameter ΔP). Value is 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 “the identification target period of the initial value correction parameter”) is the minimum. The value identified to be is used. The 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 time θ _IVC to the exhaust valve opening time 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 measured value P _sensor is minimized over the period from the intake valve closing time θ _IVC to the exhaust valve opening time θ _EVO. At this time, the value of the initial value correction parameter ΔP that minimizes the evaluation function F1 may be derived by the optimization calculation using the interior point method, the sequential planning 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 to be identified in Equation 13 is only the initial value correction parameter ΔP, the load of the optimization calculation including Equation 11 can be reduced. As the measured value P _sensor , a value based on the measured 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 and the horizontal axis is the crank angle, and _{the waveform (history) of the calculated value P calc} of the in-cylinder pressure is the solid line, and the waveform (history) of the measured value P _sensor of the in-cylinder pressure is the solid line. Each is shown. In this case, the identification target period of the initial value correction parameter ΔP is indicated by the period R3, and is from the start time θ _S (= intake valve closing time θ _IVC ) to the exhaust valve opening time θ _EVO .

Next, with reference to FIGS. 4 to 14, the effects of the above-mentioned Examples will be described in comparison with Comparative Examples.

In the comparative example, _{the calculated value P calc of the in-} cylinder pressure is derived from the equation of Equation 11 using the _{same time series (history) of the heat generation rate ROHR calc} as in this example. At this time, in the comparative example, the initial value P ₀ Is set to P ₀ = P _S. That is, in this embodiment, based on the initial value correction parameter ΔP identified as described above, the initial value P ₀ (= P _S + ΔP) corrected with respect to the measured value P _{S of the start time θ S is used.} On the other hand, in the comparative example, the measured value P _{S of the start time θ S} is used as the initial value P _0.

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

As a result of investigating the cause of such a problem, the inventor of the present application considered that the cause is that the Wiebe function cannot reproduce the heat generation rate in the period before the _{combustion start time θ SOC.} A more specific description will be given with reference to FIG. _{In FIG. 5, the waveform of the heat generation rate ROHR calc} calculated from the Wiebe function is shown by a solid line, and the waveform of the heat generation 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 accurately reproduce the period R1 _{from the combustion start time θ SOC} to the exhaust valve opening time θ _EVO, but cannot reproduce the period R2 _{from the intake valve closing time θ IVC} to the combustion start time θ _SOC. (See part X).

Therefore, within the period R1 from the combustion start time θ _SOC to the exhaust valve opening time θ _EVO , the calculated value P _calc of the in-cylinder pressure can be derived based on the Wiebe function, but within the period R2, the calculated value P of the in-cylinder pressure _calc cannot be derived based on the Wiebe function. _{When deriving the calculated value P calc} of the in-cylinder pressure based on the Wiebe function within the period R1 from the combustion start time θ _SOC to the exhaust valve opening time θ _EVO , as described above, the numerical integration related to the equation of Equation 11 is performed. It is necessary to set _{the initial value P 0} of the in-cylinder pressure for this purpose. In this case, the initial value P ₀ of the in-cylinder pressure is the value of the in-cylinder pressure before the combustion start time θ _SOC.

However, the measured value of the in-cylinder pressure before the combustion start time θ _SOC does not substantially contribute to the parameter identification of the Wiebe function. Therefore, if the 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 small change in the initial value P 0} has a relatively large effect on _{the calculated value P calc} (θ) of the in-cylinder pressure when the in-cylinder volume V becomes small. This means that the accuracy of the calculated value of the in-cylinder pressure derived by using the Wiebe function cannot be easily improved by the method (comparative example) in which _{the actually measured value P S} of the in-cylinder pressure is easily used as the initial value P _0. To do.

In this regard, according to the present embodiment, as described above, the initial value P ₀ of the integration operation according to the equation of Equation 11 is corrected by the initial value correction parameter ΔP with respect to the actually measured value P _S of the start time θ _S. The initial value P ₀ (= P _S + ΔP) is used. The initial value correction parameter ΔP has been identified so as to minimize the evaluation function F1. Therefore, according to this 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 measured value P sensor} in the combustion period is reduced, and the accuracy of the calculated value of the in-cylinder pressure derived by using the Wiebe function can be improved even in the combustion period.

By the way, in the method of incorporating the Wiebe function into the equation of Equation 11 and identifying the value of the Wiebe function parameter that minimizes the error evaluation value with respect to _{the measured value P sensor of the in-cylinder pressure (hereinafter referred to as "identification method 1").} , The calculation load becomes significantly large. This requires an optimization calculation that includes a differential equation for the in-cylinder pressure of equation 11 with a large number of Wiebe function parameters to identify (eg, _{four parameters a, m, θ soc} , and Δθ). Because. When the combination Wiebe function is used, the number of Wiebe function parameters is further increased, and the calculation load can be enormous.

In this regard, according to this embodiment, the value of the Wiebe function parameter that minimizes the error evaluation value with respect _{to the heat generation rate ROHR sensor} is identified, and the error evaluation value is obtained with respect to _{the measured value P sensor of the in-cylinder pressure.} The identification of the initial value correction parameter that is the minimum is performed separately. The computational load for identifying the values of the Wiebe function parameters is as usual. Further, as for the calculation load for identifying the initial value correction parameter, as described above, since the parameter to be identified is only the initial value correction parameter ΔP, the calculation load for the optimization calculation including the equation 11 can be small. As a result, according to this embodiment, the calculation load can be significantly reduced as compared with the above-mentioned identification method 1.

In this way, according to this embodiment, it is possible to improve the accuracy of the calculated value of the in-cylinder pressure derived by using the Wiebe function without significantly increasing the calculation load for identifying the Wiebe function parameter. ..

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

Specifically, as the first verification, operation data (test condition 1) was obtained from a 3000cc direct-injection diesel engine with in-line 4-cylinder engine on the engine bench, which resulted in 3-stage combustion at a rotation speed of 1600 rpm. Then, the value of the Wiebe function parameter was identified by the formula of formula 4 for the _{heat generation rate ROHR true} calculated by the formulas of equations 5 and 6 from _{the measured value P sensor} of the in-cylinder pressure acquired by the in-cylinder pressure sensor. _{The apparent} heat generation rate ROHR was calculated using the equation of Equation 7 and the value of the Wiebe function parameter. The Wiebe function parameters were identified by an identification method that took heat loss into account. _{The apparent} heat generation rate ROHR calculated from the values of the identified Wiebe function parameters is shown in FIG. 6, the heat generation rate ROHR _apparent by the solid lines, the heat generation rate _{ROHR: sensor} are respectively shown by broken lines. From FIG. 6, it can be seen that even the heat generation rate history of a complicated shape, which is three-stage combustion, can be identified with high accuracy.

_{Therefore, based on the apparent} heat generation rate ROHR obtained from the Wiebe function with the identified Wiebe function parameter value and the differential equation related to the in-cylinder pressure of Equation 11, the exhaust valve opens from the _{intake valve closing time θ IVC by numerical integration. The calculated value P calc} of the in-cylinder pressure up to the time θ _EVO was derived.

At this time, in the comparative example, P ₀ = P _IVC = 150 [kPa]. _{The result of deriving the calculated value P calc} of the in-cylinder pressure by the comparative example is shown in FIG. In FIG. 7, the calculated value P _calc of the in-cylinder pressure is shown by a solid line, and the measured value P _sensor of the in-cylinder pressure is shown 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 at the maximum near the top dead center.

In this example, the value of the initial value correction parameter ΔP was identified by the optimization calculation from the equation of Equation 13. The value of the initial value correction parameter ΔP at this time was 27 [kPa]. Using the value of this initial value correction parameter ΔP, the initial value P ₀ (= P _S + ΔP) of the in-cylinder pressure was calculated from the above correction formula, and the result of deriving _{the calculated value P calc of the in-cylinder pressure is shown in FIG.} Shown. In FIG. 8, the calculated value P _calc of the in-cylinder pressure is shown by a solid line, and the measured value P _sensor of the in-cylinder pressure is shown by a broken line. As shown in FIG. 8, according to this embodiment, it can be seen that _{the calculated value P calc} of the in-cylinder pressure _{is almost the same as the measured value P sensor of the in-cylinder pressure.}

As a second verification, the results of verification in a single-stage combustion (test condition 2) at a rotation speed of 1200 rpm in an in-line 4-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 values of the identified Wiebe function parameters. 9 shows, the heat generation rate ROHR _apparent by the solid lines, the heat generation rate _{ROHR: sensor} are respectively shown by broken lines. From FIG. 9, it can be seen that even the heat generation 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 a comparative example. In FIG. 10, the calculated value P _calc of the in-cylinder pressure is shown by a solid line, and the measured value P _sensor of the in-cylinder pressure is shown by a broken line. In the comparative example, as in the first verification, the calculated value P _{calc of the cylinder pressure is about 1 [MPa] lower than the measured value P sensor} of the cylinder pressure by the cylinder pressure sensor at the maximum near the top dead center. became.

In this example, the value of the initial value correction parameter ΔP was identified by the optimization calculation from the equation of Equation 13, and 29 [kPa] was obtained as the value of the initial value correction parameter ΔP. Using the value of this initial value correction parameter ΔP, the initial value P ₀ (= P _S + ΔP) of the in-cylinder pressure was calculated from the above correction formula, and the result of deriving _{the calculated value P calc of the in-cylinder pressure is shown in FIG.} Shown. In FIG. 11, the calculated value P _calc of the in-cylinder pressure is shown by a solid line, and the measured value P _sensor of the in-cylinder pressure is shown by a broken line. As shown in FIG. 11, according to this embodiment, it can be seen that _{the calculated value P calc} of the in-cylinder pressure _{is substantially the same as the 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 rotation speed of 1200 rpm in an in-line 4-cylinder 3000 cc direct injection diesel engine are shown in FIGS. 12 to 14. FIG. 12 shows the _apparent heat generation rate ROHR calculated from the values of the identified Wiebe function parameters. FIG 12, the heat generation rate ROHR _apparent by the solid lines, the heat generation rate _{ROHR: sensor} are respectively shown by broken lines. From FIG. 12, it can be seen that even the heat generation rate history of staged 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 a comparative example. In FIG. 13, the calculated value P _calc of the in-cylinder pressure is shown by a solid line, and the measured value P _sensor of the in-cylinder pressure is shown by a broken line. In the comparative example, as in the first verification, the calculated value P _{calc of the cylinder pressure is about 1 [MPa] lower than the measured value P sensor} of the cylinder pressure by the cylinder pressure sensor at the maximum near the top dead center. became.

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

From the above, it was confirmed that in this embodiment, both the heat generation rate and the in-cylinder pressure of a complicated shape can be reproduced with high accuracy. In addition, the effectiveness of this method of identifying the value of the Wiebe function parameter for the heat generation rate ROHR _{sensor and the initial value correction parameter ΔP for the measured value P sensor of the in-cylinder pressure was confirmed.}

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. In the following, when the Wiebe function parameter and the initial value correction parameter are not distinguished, they are collectively referred to as "model parameter". In the following, 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, it is applicable even when the Wiebe function parameter is identified by an identification method that takes heat loss into consideration. In this case, a heat loss model for deriving the heat loss according to the operating conditions is used, and the parameters (model parameters) of the heat loss model may be identified.

FIG. 15 is a diagram showing an example of an in-vehicle control system 1 including a parameter identification device 10. In FIG. 15, in addition to the vehicle-mounted control system 1, the driving 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. The operation data does not necessarily have to be the data related to the same individual as the engine system 4, but may be the data related to the same engine system including the internal combustion engine of the same type. The operation data is each value obtained during the actual operation of the engine system 4, and is a combination of each value of each 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. May include. The operation data can be obtained, 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 measured in-cylinder pressure data is, for example, a set of in-cylinder pressure values for each crank angle, 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 the 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 for each injection. (In the example shown in FIG. 16, pilot injection, pre-injection, etc.). In the example shown in FIG. 16, each value of each operating condition parameter and the 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 powered by an internal combustion engine, and includes a hybrid vehicle powered by an internal combustion engine and an electric motor. The type of 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 does not need to include the in-cylinder pressure sensor. Installation of the in-cylinder pressure sensor is disadvantageous in terms of cost, durability, and maintainability.

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

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

In the example shown 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 unit 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 and processes the data, and then 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 an OS (Operating System) and application software that 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 for storing data related to application software or the like.

The drive device 104 reads a program from a recording medium 105, for example, a flexible disk, and installs the program 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 a peripheral device having a communication function and a parameter identification device 10 connected via a network constructed by a data transmission line such as a wired and / or wireless line.

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

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

See FIG. 15 again. 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 measurement value calculation unit 13, and an optimization calculation unit 14. Further, the parameter identification device 10 includes a model parameter storage unit 15 (an example of a relational expression derivation 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. 17, for example. This can be achieved 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, for example, the auxiliary storage unit 103 shown in FIG.

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 heat generation rate actual measurement value calculation unit 13 calculates the heat generation rate ROHR sensor} based on the cylinder pressure data acquired by the cylinder pressure data acquisition unit 12 for each operating condition. _{Specifically, the heat generation rate actual measurement value calculation unit 13 calculates the heat generation rate ROHR sensor} based on the cylinder pressure data acquired by the cylinder pressure data acquisition unit 12 for each operating condition. The calculation method of the heat generation rate ROHR _{sensor is as described above.}

The optimization calculation unit 14 identifies model parameters 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 (see, for example, _{Equation 4) based on the heat generation rate ROHR sensor} calculated by the heat generation rate measurement value calculation unit 13 for each operating condition. To do. The Wiebe function parameter identification unit 141 identifies each value (optimal 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 each operating condition 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. The 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 identification unit 141 is used for deriving the _{heat generation rate ROHR calc by the Wiebe function.} The derived heat generation rate ROHR _calc is used for numerical integration for deriving the _{calculated value P calc} of the in-cylinder pressure based on the equation of Equation 11. _{The initial value correction parameter identification unit 142 derives the calculated value P calc} of the in-cylinder pressure based on the equation of Equation 11 while changing the value of the initial value correction parameter ΔP, and minimizes the evaluation function F1. (Optimal value) is identified.

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

The initial value setting unit 1420 sets the initial value P ₀ of the in-cylinder pressure used for the optimization calculation. _{The initial value P 0} of the in-cylinder pressure used in 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 generation rate derivation unit 1421 calculates the _{heat generation rate ROHR calc} based on each value of the Wiebe function parameters identified by the Wiebe function parameter identification unit 141. As described above, the heat generation rate derivation unit 1421 is from the combustion start time θ _soc to the exhaust valve opening time θ _{EVO in the identification target period (start time θ s} to exhaust valve opening time θ _EVO ) of the initial value correction parameter ΔP. Calculate the heat generation rate ROHR _{calc only for the period.} At this time, the heat generation rate derivation unit 1421 calculates the _{heat generation rate ROHR calc} based on each value of the Wiebe function parameter identified by the Wiebe function parameter identification unit 141.

The in-cylinder pressure derivation unit 1422 includes the heat generation rate ROHR _{calc calculated by the heat generation rate derivation 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. Based on the formula of 11, the 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. Specifically, the in-cylinder pressure derivation unit 1422 uses the heat generation rate ROHR _{calc as the apparent} heat generation rate ROHR _{for the period from the combustion start time θ soc} to the exhaust valve opening time θ _EVO , and calculates the in-cylinder pressure. Derivation of P _calc. On the other hand, the in-cylinder pressure derivation unit 1422 calculates the in-cylinder pressure for the _{remaining period (start time θ s} to combustion start time θ _soc ) with a predetermined value (here, 0) _{as the apparent heat generation rate ROHR.} Derivation of P _calc.

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 derivation 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 operating condition (for each operating condition ID) and stored in the model parameter storage unit 16. FIG. 18 is a diagram conceptually showing 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 associated with 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 the 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 and combustion by main injection).

The model parameter storage unit 15 preferably has a relational expression (for example, first-order) representing the relationship between each optimum value of the model parameter and each operating condition based on the data (see FIG. 18) in the model parameter storage unit 16. (Polynomial) (an example of the second relational expression) is calculated. 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 the polynomial modeling information in the model parameter storage unit 16 instead of the data shown in FIG. In this case, the storage capacity required in the model parameter storage unit 16 can be significantly reduced as compared with the case of holding the data (map data) shown in FIG.

The polynomial modeling information may be generated, for example, as follows. 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 polynomials to determine the relationship between each optimum value of the Wiebe function parameter and each operating condition. It may be approximated.

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 the equation 14 is used for each Wiebe function parameter. According to this 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. This makes it possible to estimate the value of each Wiebe function parameter corresponding to an arbitrary operating condition with high accuracy.

Similarly, the model parameter storage unit 15 preferably uses the following first-order polynomials based on the data in the model parameter storage unit 16 to set 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 this 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. This makes it possible to estimate the value of the initial value correction parameter corresponding to an arbitrary operating condition with high accuracy.

The equations 14 and 15 are first-order polynomials, but other polynomials such as second-order polynomials may be used.

By the way, in the data shown in FIG. 18, as described above, each optimum value of the model parameter is associated with each operation condition (each combination of the operation condition parameters). Therefore, if data on a large number of operating conditions are obtained, it is highly possible that the values of model parameters that match a certain arbitrary operating conditions can be extracted. However, the operating conditions of the internal combustion engine are extremely diverse depending on the combination of the engine speed, the amount of air, the fuel injection pressure, and the like. It is not realistic to derive each optimum value of the model parameter over such various operating conditions.

On the other hand, when polynomial modeling information is obtained using polynomials such as the above equations 14 and 15 based on the data shown in FIG. 18, a small amount of data is used over various operating conditions. , It is possible to derive each optimum value of the model parameter. That is, the polynomial modeling information, the values of the coefficients β ₀ ~β _n for each Wiebe function the parameters, may be included each value of the initial value coefficient β1 ₀ ~β1 _n of correction parameters respectively, each operating condition (operating It is not necessary to link with each combination of condition parameters). Therefore, the polynomial modeling information has an overwhelmingly smaller amount of data than the data shown in FIG. On the other hand, the polynomial modeling information can accurately derive each optimum value of the model parameter over various operating conditions even though the amount of data is small.

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

As described above, the relational expression storage unit 17 stores the above-mentioned equation 11 which is a relational expression (an example of the first relational expression) used for the optimization operation in the optimization calculation unit 14.

FIG. 19 is a flowchart showing an example of the process executed by the parameter identification device 10. The process shown in FIG. 19 is executed offline, for example. Further, the process shown in FIG. 19 is executed for each operation condition with respect to the operation data related to a plurality of operation conditions in the operation data storage unit 2, for example. The operating conditions are defined by the combination of the values of the operating condition parameters described above.

In step S1600, the operation data acquisition unit 11 acquires operation data related to one or more operation conditions (operation condition IDs) 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 the in-cylinder pressure data for each operation condition ID (see FIG. 12).

In step S1601, the operation data acquisition unit 11 determines one specific operation condition in a predetermined order (for example, ascending order of the operation condition ID) from the operation data related to 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 the in-cylinder pressure data among the operation data selected in step S1601.

In step S1603, the heat generation rate actual measurement value 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 minimizes the evaluation function F (see, for example, equation 4) based on _{the heat generation rate ROHR sensor obtained in step S1603.} Derivation of the value (optimum value).

In step S1606, the initial value correction parameter identification unit 142 of the optimization calculation unit 14 initially obtains each value (optimal value) of the Wiebe function parameter obtained in step S1604 and the in-cylinder pressure data acquired in step S1602. The optimum value of the value correction parameter ΔP is derived. That is, the initial value correction parameter identification unit 142 derives the value (optimal 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 step S1604 and step S1606 in the model parameter storage unit 16 in association with the current operation 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, when the determination result is "NO", the process shown in FIG. 19 returns to step S1601, operation data related to one 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 of generating the polynomial modeling information is as described above.

In step S1614, the model parameter storage unit 15 stores the polynomial modeling information in the model parameter storage unit 16.

According to the process shown in FIG. 19, by acquiring operation data covering 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 can be obtained. Can be done. This makes it possible to estimate the value of each model parameter corresponding to an arbitrary operating condition 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 executed at the same time, 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, the engine control device 30 will be described with reference to FIG. 20 with reference to FIG. 15 again.

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). An example of a unit) and a relational expression storage unit 39 (an example of a first storage unit) are included. 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 shown in FIG. 13 executes one or more programs in the main storage unit 102 and the like. It can be realized by.

The operating condition determination unit 32 determines the operating conditions of the internal combustion engine based on the information obtained from the sensor group 6. The operating conditions are used when extracting each optimum value (each identification value) of the model parameter according to the operating condition from the model parameter storage unit 16. When the above-mentioned polynomial modeling information is used, the operation condition determination unit 32 derives each value of the above-mentioned operation condition parameter as an operation condition determination result 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 generation rate ROHR calc} according to the operating conditions based on the values of the Wiebe function parameters corresponding to the operating conditions. For example, when the above-mentioned 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 the polynomial related to each Wiebe function parameter. , Derived the value of each Wiebe function parameter. 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 the operation condition most suitable for 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 generation rate ROHR calc} based on the Wiebe function using the value of each Wiebe function parameter derived or acquired.

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-mentioned 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. , 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 most suitable for each value of the operation condition parameter from the map data. Initial value to be performed Acquire the value of the correction parameter ΔP.

_{The initial value setting unit 343 sets the initial value P 0} of the in-cylinder pressure based on the value of the initial value correction parameter ΔP acquired or derived by the initial value correction parameter calculation unit 342 and the actually measured value P _S 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 the in-cylinder pressure sensor, the detection value of the in-cylinder pressure sensor at the _{intake valve closing time θ IVC can also be used.}

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

The control value calculation unit 38 calculates the control target value 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 according to the vehicle speed and the accelerator opening, a required drive torque for assisting the driver in driving the vehicle, and the like. The required drive torque for assisting the driver in driving the vehicle is determined based on, for example, information from a radar sensor or the like. The required drive torque for assisting the driver in driving the vehicle is, for example, the drive torque required to drive at a predetermined vehicle speed, the drive torque required to follow the preceding vehicle, and the vehicle speed so as not to exceed the vehicle speed limit. It may be a drive torque or the like for limiting.

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

FIG. 20 is a flowchart showing an example of processing executed by the engine control device 30. The process shown in FIG. 20 is executed, for example, during the actual operation of the engine system 4. Here, as an example, it is assumed that the above-mentioned 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 S1700, 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 representing the current state of the internal combustion engine is, for example, each value of the current operating condition parameter (information representing 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 time θ _S is the intake valve closing time θ _{IV C.} If the determination result is "YES", the process proceeds to step S1702, and if not, 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, and derives each value of the operating condition parameter corresponding to the current operating condition.

In step S1703, the Wiebe function value calculation unit 341 of the model function calculation unit 34 has each Wiebe function parameter corresponding to each value of the current operating condition parameter in the model parameter storage unit 16 based on the above-mentioned polynomial modeling information. Derivation of the value of. 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 S1704, 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 in the model parameter storage unit 16 based on the above-mentioned polynomial modeling information. Derive the value of the parameter.

In step S1705, the initial value setting unit 343 of the model function calculation unit 34, the value of the derived initial value correction parameter ΔP in step S1704, the measured value P _S of the current cylinder pressure _(detection value of the intake pressure sensor) and Based on, the initial value P ₀ of the in-cylinder pressure is set (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). _{If the current crank angle is within the period from the combustion start time θ soc} to the exhaust valve opening time θ _EVO , the Wiebe function value calculation unit 341 will use the current _{heat generation rate ROHR calc} (based on the current Wiebe function). The heat generation rate ROHR _calc ) at the current crank angle is derived. On the other hand, when the current crank angle is _{within the period from the start time θ s} to the combustion start time θ _soc , the Wiebe function value calculation unit 341 ends step S1706 without performing any processing, and proceeds to step S1707. move on.

In step S1707, the engine torque calculation unit 36 includes the current heat generation rate ROHR _{calc obtained in step S1706, the initial value P 0} of the in-cylinder pressure set in step S1704, and the number 11 in the relational expression storage unit 39. Based on the formula of, the calculated value P _calc of the current 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 time θ soc} to the exhaust valve opening time 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. Used as the rate of occurrence ROHR ( _{apparent heat generation rate ROHR).} On the other hand, when the current crank angle is _{within the period from the start time θ s} to the combustion start time θ _soc , the engine torque calculation unit 36 sets a predetermined value (0 in this example) to the heat generation rate ROHR of Equation 11. Used as (heat generation rate ROHR _apparent).

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

According to the process shown in FIG. 20, the engine control device 30 can feedback-control the engine system 4 based on, for example, the difference between the required driving force and the calculated value of the torque generated by 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 high 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.} Therefore, the engine system 4 can be controlled with high accuracy by using the calculated value of the torque generated by the internal combustion engine with high accuracy. As a result, for example, it is not necessary to excessively inject fuel into the cylinder, engine performance is improved, and fuel efficiency 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 addition, in FIG. 20, the processing for one cylinder was 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 torque generated by the internal combustion engine based on _{the calculated value P calc of the in-cylinder pressure for all the cylinders.} Further, even when the internal combustion engine has a plurality of cylinders, the operating conditions may be common, so that steps S1702 to S1705 may be executed only for one specific cylinder.

Next, an alternative example to the above-described in-vehicle control system 1 will be described with reference to FIG.

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

The vehicle-mounted control system 1A shown in FIG. 21 is different from the vehicle-mounted control system 1 shown in FIG. 15 in that the operation data acquisition unit 11 is omitted. Further, in the vehicle-mounted control system 1A shown in FIG. 21, the parameter identification device 10 is replaced by the parameter identification device 10A and the sensor group 6 is replaced by the sensor group 6A with respect to the vehicle-mounted control system 1 shown in FIG. The point is different. Regarding the components of the vehicle-mounted control system 1A shown in FIG. 21, components that may be similar to those of the vehicle-mounted control system 1 shown in FIG. 15 are designated by the same reference numerals in FIG. 21 and description thereof will be omitted.

The sensor group 6A is different from the above-mentioned sensor group 6 which does not need to include the in-cylinder pressure sensor in that the in-cylinder pressure sensor is always included.

The parameter identification device 10A differs from the parameter identification device 10 in that the in-cylinder pressure data acquisition unit 12 is replaced by the in-cylinder pressure data acquisition unit 12A. The in-cylinder pressure data acquisition unit 12A acquires the same data as the in-cylinder pressure data acquisition unit 12, but the operation data storage unit 2 acquires the same data from the sensor group 6A (in-cylinder pressure sensor). It is different for the in-cylinder pressure data acquisition unit 12 to acquire.

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 mounting state (that is, the state after the vehicle is shipped). That is, according to the vehicle-mounted 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 periodically or irregularly in the vehicle mounting state. As a result, even if there are individual differences in the characteristics of the internal combustion engine, the model parameters can be modified according to the individual differences. In addition, the model parameters can be updated even when the characteristics of the internal combustion engine change with time.

The engine control device 30 shown in FIGS. 15 and 21 is mounted on the vehicle-mounted 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 mounted on the vehicle-mounted control systems 1 and 1A in a manner including a model parameter storage unit 16 which is a part of the parameter identification devices 10 and 10A. That is, the in-vehicle control systems 1 and 1A may be realized in such a manner that the components other than the model parameter storage unit 16 among the components of the parameter identification devices 10 and 10A are not included. In this case, the model parameter storage unit 16 may store the above-mentioned data 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 the present invention is not limited to this. For example, the vehicle drive device to be controlled may include a transmission, an electric motor, a clutch, or the like in addition to or in place of the engine system 4.

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

For example, in the above-described embodiment, the value of the initial value correction parameter ΔP of the in-cylinder pressure has been identified, but the present invention is not limited to this. For example, the initial value P ₀ of the in-cylinder pressure may be identified. Specifically, an initial value P ₀ of the evaluation function F1 (see number 13) minimized by the optimization calculation may be identified. In this case, similarly, 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.

Further, in the above-described embodiment, a vehicle equipped with an engine is targeted as an example, but the target is arbitrary as long as the engine is provided. For example, the target may be a railroad vehicle having an engine, a ship having an engine, a construction machine having an engine, a motorcycle having an engine (a type of vehicle), an aircraft having an engine, a helicopter having an engine, and the like.

Further, in the above-described embodiment, the specific differential equation shown 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 shown by Equation 11 is used. Good. For example, the equivalent expression may be the expression of Equation 5. As an equivalent equation, for the differential equation shown in Equation 11, the Wiebe function is set to, for example, f (θ), and the general solution of the differential equation shown in Equation 11 (general solution regarded as a first-order differential equation with respect to P) is used. It may be an equation derived by finding it. In this case as well, 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。
The following additional notes will be further disclosed with respect to the above examples.
[Appendix 1]
A relational expression storage unit that stores the first relational expression between the heat generation rate due to combustion in the cylinder of the internal combustion engine and the cylinder pressure of the internal combustion engine, and
An acquisition unit that acquires the measured value of the in-cylinder pressure, and
A heat generation rate derivation unit that derives the calculated value of the heat generation rate based on the Wiebe function,
An initial value setting unit that sets the initial value of the in-cylinder pressure based on the value of the initial value parameter,
An in-cylinder pressure deriving unit that derives 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 including a parameter identification unit that identifies the value of the initial value parameter based on the relationship between the measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure.
[Appendix 2]
The parameter identification unit identifies the value of the initial value parameter so that the evaluation value related to the error of the calculated value of the in-cylinder pressure with respect to the actually measured value of the in-cylinder pressure over the identification target period is minimized, as described in Appendix 1. Internal combustion engine parameter identification device.
[Appendix 3]
The internal combustion engine according to Appendix 2, wherein the identification target period is from the start time after the intake valve closing time and before the combustion start time to the end time after the combustion start time and before the exhaust valve opening time. Parameter identification device.
[Appendix 4]
The start time is the intake valve closing time, and the ending time is the exhaust valve opening time.
The internal combustion engine parameter identification device according to Appendix 3, wherein the evaluation value is the sum of squares of the errors.
[Appendix 5]
The in-cylinder pressure derivation unit derives the calculated value of the in-cylinder pressure within the period after the combustion start time 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 the period prior to the combustion start time of the above 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 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 as the initial value.
The in-cylinder pressure derivation unit derives the calculated value of the in-cylinder pressure by performing the integration operation related to the first relational expression in the integration section starting from the start time.
The internal combustion engine parameter identification device according to any one of Supplementary note 3 to 5, wherein the in-cylinder pressure derivation unit uses the initial value as the value of the in-cylinder pressure at the start time in the integration calculation.
[Appendix 7]
The internal combustion engine parameter identification apparatus according to any one of Supplementary note 1 to 6, wherein the value of each parameter of the Wiebe function is identified based on the measured value of the in-cylinder pressure.
[Appendix 8]
The first relational expression includes any one of Appendix 1 to 7, including a functional expression of the heat generation rate that changes according to the crank angle and a functional expression of the in-cylinder volume that changes according to the crank angle. The internal combustion engine parameter identification device described in the section.
[Appendix 9]
The first relational expression is the following differential equation relating to the in-cylinder pressure or an equation 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. The internal combustion engine according to any one of Appendix 1 to 8. Parameter identification device.
[Appendix 10]
The internal combustion engine parameter identification according to any one of Appendix 1 to 9, wherein the parameter identification unit identifies the value of the initial value parameter for each operating condition for a plurality of operating conditions of the internal combustion engine. apparatus.
[Appendix 11]
10 is described in Appendix 10, further comprising a relational expression derivation unit for deriving a second relational expression between the value of the initial value parameter identified for each operating condition and each value of a plurality of operating condition parameters representing the operating condition. Internal engine parameter identification device.
[Appendix 12]
An in-vehicle control system installed in a vehicle equipped with an internal combustion engine.
A first storage unit that stores the first relational expression between the heat generation rate due to combustion in the cylinder of the internal combustion engine and the pressure inside the cylinder,
A second storage unit that stores identification value information that represents the identification value of the initial value parameter or information that can derive the identification value, and
A heat generation rate calculation unit that derives the calculated value of the heat generation rate based on the Wiebe function,
An identification value derivation unit that acquires or derives the identification value based on the identification value information stored in the second storage unit.
An initial value setting unit that sets the initial value of the in-cylinder pressure based on the identification value acquired or derived by the identification value derivation unit.
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 a calculated value of the heat generation rate.
[Appendix 13]
It also includes an operating condition judgment unit that determines the operating conditions of the internal combustion engine.
The vehicle-mounted control system according to Appendix 12, wherein the identification value deriving unit derives the identification value according to the operating conditions.
[Appendix 14]
The identification value information includes a plurality of operating condition parameters representing the operating conditions and a second relational expression between the identified values.
The vehicle-mounted control system according to Appendix 13, wherein the identification value deriving unit derives the identification value according to the operating conditions based on the second relational expression.
[Appendix 15]
The initial value setting unit sets a value obtained by adding the identification value to the detected value of the intake pressure obtained from the intake pressure sensor or the in-cylinder pressure sensor as the initial value, any of the appendices 12 to 14. The in-vehicle control system according to item 1.
[Appendix 16]
The in-cylinder pressure calculation unit derives the calculated value of the in-cylinder pressure after the combustion start time based on the calculated value of the heat generation rate, and the calculated value of the in-cylinder pressure before the combustion start time is obtained. The in-vehicle control system according to any one of Supplementary note 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 the result obtained by identifying the value of the initial value parameter so as to minimize the evaluation value related to the difference between the measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure. , The in-vehicle control system according to any one of Supplementary note 12 to 16, which is generated.
[Appendix 18]
The vehicle-mounted control system according to any one of Appendix 12 to 17, further comprising a vehicle control unit that controls a vehicle based on the calculated value of the in-cylinder pressure derived by the in-cylinder pressure calculation unit.
[Appendix 19]
Obtained the first relational expression between the heat generation rate due to combustion in the cylinder of the internal combustion engine and the pressure inside the cylinder of the internal combustion engine.
Obtain the measured value of the in-cylinder pressure
Based on the Wiebe function, the calculated value of the heat generation rate is derived,
The initial value of the in-cylinder pressure is set based on the value of the initial value parameter.
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 performed by a computer, which comprises identifying the value of the initial value parameter based on the relationship between the measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure.
[Appendix 20]
Obtained the first relational expression between the heat generation rate due to combustion in the cylinder of the internal combustion engine and the pressure inside the cylinder of the internal combustion engine.
Obtain the measured value of the in-cylinder pressure
Based on the Wiebe function, the calculated value of the heat generation rate is derived,
The initial value of the in-cylinder pressure is set based on the value of the initial value parameter.
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.
The value of the initial value parameter is identified based on the relationship between the measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure.
A program that causes a computer to perform processing.

1, 1A In-vehicle control system 2 Operation data storage unit 4 Engine system 6, 6A Sensor group 10, 10A Parameter identification device 11 Operation data acquisition unit 12, 12A In-cylinder pressure data acquisition unit 13 Heat generation rate actual measurement value calculation unit 14 Optimization calculation Part 15 Model parameter storage unit 16 Model parameter storage unit 17 Relational expression storage unit 30 Engine control device 32 Operating condition judgment 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 generation rate derivation unit 1422 In-cylinder pressure derivation unit 1423 Parameter identification unit

Claims (9)

A relational expression storage unit that stores the first relational expression between the heat generation rate due to combustion in the cylinder of the internal combustion engine and the cylinder pressure of the internal combustion engine, and
An acquisition unit that acquires the measured value of the in-cylinder pressure, and
A heat generation rate actual measurement value calculation unit that calculates the actual measurement value of the heat generation rate based on the actual measurement value of the in-cylinder pressure,
Based on the relationship between the measured value of the heat generation rate and the heat generation rate obtained from the Wiebe function, the parameters of the Wiebe function are set for the first identification target period from the combustion start time or fuel injection time to the exhaust valve opening time. Wiebe function parameter identification part to identify,
A heat generation rate deriving unit that derives a calculated value of the heat generation rate based on the parameters of the Wiebe function identified by the Wiebe function parameter identification unit.
The measured values of the cylinder pressure in the earlier start timing the combustion start timing a intake valve closing timing after, based on the value of the initial value correction parameter of the cylinder pressure, the cylinder pressure at the start timing The initial value setting section that sets the initial value and
An in-cylinder pressure deriving unit that derives 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.
A parameter identification unit that identifies the value of the initial value correction parameter during the second identification target period from the start time to the exhaust valve opening time based on the relationship between the measured value of the in-cylinder pressure and the calculated value of the in-cylinder pressure. Internal combustion engine parameter identification device, including. The parameter identification unit identifies the value of the initial value correction parameter so that the evaluation value related to the error of the calculated value of the in-cylinder pressure with respect to the actually measured value of the in-cylinder pressure over the second identification target period is minimized. The internal combustion engine parameter identification device according to claim 1. Before Symbol evaluation value is the square sum of the error, an internal combustion engine parameter identification device according to claim 2. The in-cylinder pressure derivation unit derives the calculated value of the in-cylinder pressure in the period after the combustion start time of the second identification target period based on the calculated value of the heat generation rate, and derives the second. Any of claims 1 to 3, wherein the calculated value of the in-cylinder pressure within the period before the combustion start time of the identification target period is derived based on a predetermined value instead of the calculated value of the heat generation rate. The internal combustion engine parameter identification apparatus according to claim 1. The initial value setting unit sets a value obtained by adding the value of the initial value correction parameter to the measured value of the in-cylinder pressure at the start time as the initial value.
The in-cylinder pressure derivation unit derives the calculated value of the in-cylinder pressure by performing the integration operation related to the first relational expression in the integration section starting from the start time.
The internal combustion engine parameter identification device according to any one of claims 1 to 4, wherein the in-cylinder pressure derivation unit uses the initial value as the value of the in-cylinder pressure at the start time in the integration calculation. The first relational expression is the following differential equation relating to the in-cylinder pressure or an equation equivalent to the differential equation.

The internal combustion engine according to any one of claims 1 to 5, wherein 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. The internal combustion engine according to any one of claims 1 to 6, wherein the parameter identification unit identifies the value of the initial value correction parameter for each operating condition for a plurality of operating conditions of the internal combustion engine. Parameter identification device. The seventh aspect of claim 7, further comprising a relational expression derivation unit for deriving a second relational expression between the value of the initial value parameter identified for each operating condition and each value of a plurality of operating condition parameters representing the operating condition. Internal engine parameter identification device. Obtained the first relational expression between the heat generation rate due to combustion in the cylinder of the internal combustion engine and the pressure inside the cylinder of the internal combustion engine.
Obtain the measured value of the in-cylinder pressure
Based on the measured value of the in-cylinder pressure, the measured value of the heat generation rate is calculated.
Based on the relationship between the measured value of the heat generation rate and the heat generation rate obtained from the Wiebe function, the parameters of the Wiebe function are set for the first identification target period from the combustion start time or the fuel injection time to the exhaust valve opening time. Identify and
Based on the identified parameters of the Wiebe function, the calculated value of the heat generation rate is derived.
The measured values of the cylinder pressure in the earlier start timing the combustion start timing a intake valve closing timing after, based on the value of the initial value correction parameter of the cylinder pressure, the cylinder pressure at the start timing Set the initial value and
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 second identification target period from the start time to the exhaust valve opening time and the value of the initial value correction parameter are identified. , A method of identifying internal combustion engine parameters performed by a computer.

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