JP2010053820A - Method of adapting transient correction parameter of fuel injection pattern of internal combustion engine - Google Patents

Abstract

An object of the present invention is to accurately adapt a transient correction parameter for correcting a steady adaptive injection pattern in a transient operation state and reduce the man-hour required for the adaptation.
A pilot increase amount and a main advance amount are adapted so that a peak point in a change characteristic of a heat generation rate in a combustion chamber coincides with a target point even in a transient operation state. In this adaptation, a plurality of measurement points are arranged within the measurement range corresponding to the combination of pilot increase and main advance angle amount, and `` correspondence between measurement points and peak points '' in a specific transient operation state for each measurement point Is actually measured, and a measurement point that matches the peak point with the target point is identified from the plurality of correspondence relationships, the target point, and a known analysis method, and the pilot increase amount and the main advance angle amount are adapted. Using the relationship that “the peak position always advances regardless of whether the pilot increase amount or the main advance amount increases,” the target point is included in the corresponding peak range and the narrow measurement range is efficiently identified. The
[Selection] Figure 24

Description

  The present invention relates to a method for adapting a transient correction parameter of a fuel injection pattern of an internal combustion engine, and a fuel injection pattern determination device for an internal combustion engine using a transient correction parameter adapted using the adaptation method.

  In an internal combustion engine, it is necessary to determine control parameters such as a fuel injection pattern in consideration of misfire suppression, ensuring sufficient output torque, and suppressing increase in combustion noise. For this reason, in general, the control parameters are adapted in advance through experiments or the like so as to obtain an optimum combustion state in consideration of the above viewpoints and the like for each steady operation state (combination of injection amount and operation speed). The steady operation state refers to, for example, an operation state in which the injection amount and the operation speed are maintained constant.

In Patent Document 1, for each steady operation state, characteristic values representing the combustion state are measured for a plurality of preset representative values (representative combinations) for the control parameter. Based on the measurement result and a predetermined analysis method, a model formula that defines the relationship between the control parameter and the characteristic value is obtained. Control parameters are adapted using this model equation.
JP 2004-263680 A

  By the way, as the specific value representing the combustion state, the magnitude of the heat generation rate and the crank angle (peak height and peak corresponding to the peak in the “change characteristics of the heat generation rate in the combustion chamber with respect to the progress of the crank angle of the internal combustion engine”). Position) (see FIG. 5 described later). This peak height and peak position have a strong correlation with misfire occurrence, output torque, combustion noise, and the like. In addition, the peak height and peak position are determined by the fuel injection pattern (injection timing, injection amount, etc.).

  Therefore, for each steady operation state, the point (peak point) corresponding to the combination of peak height and peak position is the target point (operation state (combination of injection amount and operation speed) corresponding to the optimum combustion state). The fuel injection pattern can be adapted to be variable). Hereinafter, the fuel injection pattern adapted so that the peak point becomes the target point in the steady operation state will be referred to as a “steady adapted injection pattern”.

  In the steady operation state, as described above, the peak point corresponds to the current operation state by injecting fuel with the above-mentioned steady adaptive injection pattern corresponding to the current operation state (combination of injection amount and operation speed). The optimum combustion state is obtained in consideration of the above viewpoint. On the other hand, in an operating state (transient operating state) in which the injection amount and operating speed are changing, even if fuel is injected with the above-described steady adaptive injection pattern corresponding to the current operating state, the peak point is the current operating state May shift from the target point corresponding to the above, and an optimal combustion state in consideration of the above viewpoint cannot be obtained. This is based on the fact that a response delay or the like of the intake oxygen concentration (and hence the oxygen concentration in the combustion chamber) occurs in the transient operation state (details will be described later).

  Therefore, in the transient operation state, the steady-fit injection pattern is used with a plurality of parameters (transient correction parameters) so that the peak point becomes a target point corresponding to the current operation state (combination of injection amount and operation speed). It is conceivable to inject fuel with a fuel injection pattern obtained by correcting the above. In this case, a plurality of transient correction parameters are adapted so that the peak point in the transient operation state becomes a target point corresponding to the current operation state for each operation state (combination of injection amount and operation speed). There is a need.

  In the present invention, the transient correction of the fuel injection pattern of the internal combustion engine that can accurately adapt a plurality of transient correction parameters for correcting the steady adaptive injection pattern in the transient operation state and can reduce the man-hour required for the adaptation. It is to provide a method for adapting parameters.

  In the method for adapting the transient correction parameter according to the present invention, the plurality of transient correction parameters are correlated at least with the peak height and the peak position, and the peak regardless of which of the plurality of transient correction parameters increases. What has a specific relationship that the position moves only to one side of the advance side and the retard side is adopted.

  For example, when a pattern in which pilot injection is performed prior to main injection is adopted as the steady adaptive injection pattern, the injection timing of the main injection corresponds to the steady adaptive injection pattern as the plurality of transient correction parameters For correcting the advance amount (main advance amount) from the timing corresponding to the stationary adaptive injection pattern for correcting from the timing to perform, and the injection amount of the pilot injection from the amount corresponding to the stationary adaptive injection pattern Two parameters can be employed: an increase amount (pilot increase) from an amount corresponding to the steady adaptive injection pattern. In this case, the specific relationship that “the peak position moves only to the advance side regardless of which of the main advance angle amount and the pilot increase amount” is obtained.

  In the method for adapting transient correction parameters according to the present invention, “measurement processing” for a certain measurement point (a point corresponding to a combination of a plurality of transient correction parameters) is a plurality of transient correction parameters corresponding to that point. The peak point based on the “change characteristic of heat generation rate” obtained by actually injecting fuel in a specific transient operation state with the fuel injection pattern obtained by correcting the steady adaptive injection pattern based on the combination of This is a process for measuring.

  Here, the “specific transient operation state” refers to a transient operation state in which the degree of transient is a predetermined reference level. As the “specific transient operation state”, for example, the intake oxygen concentration already obtained in the steady operation state when the steady adaptation injection pattern is adapted (steady adaptation intake oxygen concentration) and (using a sensor or the like) ) A transient operation state in which the amount of difference from the measured current intake oxygen concentration (hereinafter referred to as “intake oxygen concentration difference”) becomes a predetermined reference amount may be employed. This is based on the fact that the degree of transient (which can be expressed by a change gradient of the injection amount and the operation speed) and the difference amount of the intake oxygen concentration are in a substantially proportional relationship.

  Thus, the “specific transient operation state” is used in the measurement process based on the following reason. In other words, when the degree of transient (injection amount and change gradient in operating speed, specifically, the difference in the intake oxygen concentration, etc.) fluctuates, the peak point measured by the measurement process fluctuates. The transient correction parameters that are made can also vary. Here, it is known that the degree of transient and the value of the transient correction parameter to be adapted are in a substantially proportional relationship. Therefore, if the transient correction parameter is adapted only in the specific transient operation state, based on this adaptation result, the transient operation state different from the specific transient operation state (the transient operation is different from the predetermined reference level). The value of the transient correction parameter to be adapted in the state (specifically, for example, the transient operation state in which the difference amount of the intake oxygen concentration is different from the predetermined reference amount) can be estimated. In other words, the operation of adapting the transient correction parameter for the transient operation state different from the specific transient operation state can be omitted.

  Further, in the method for adapting transient correction parameters according to the present invention, the measurement processing is respectively performed on a plurality of measurement points constituting an outline of a certain measurement range (measurement region) represented by a combination of the plurality of transient correction parameters. A region in which a contour is constituted by a plurality of obtained peak points is referred to as a “peak region” corresponding to the measurement range (measurement region).

  In the method for adapting the transient correction parameter according to the present invention, the transient correction parameter is adapted by executing the following first to sixth steps for each operation state (injection amount and operation speed). First, the first step will be described.

  In the first step, a first measurement range represented by a combination of a plurality of transient correction parameters is determined. The first measurement range is preferably a range defined by a combination of ranges from an allowable minimum value to a maximum value for each transient correction parameter. This is based on the idea that the first measurement range is preferably as wide as possible so that the target point can be included in the peak region corresponding to the first measurement range. Here, the allowable maximum value (minimum value) for each transient correction parameter is the steady adaptive injection pattern itself when the value to be adapted for each transient correction parameter exceeds that value (below that value). Is a value determined to be inappropriate.

  In a more preferred aspect, in the first step, a plurality of measurement points included in the first measurement range are further determined. The plurality of measurement points include a point constituting the outline of the first measurement range and a point inside the first measurement range. Further, a plurality of measurement areas obtained by dividing the first measurement range are determined. Each outline of the plurality of measurement regions is constituted by a part of the plurality of measurement points.

  Next, the second step will be described. In the second step, the measurement process is performed on one of the measurement points (first point) inside the first measurement range. In the more preferable aspect, as the first point, one of the points within the first measurement range is selected from the plurality of measurement points determined in the first step, and the measurement process is performed on the first point. Done.

  Next, the third step will be described. In the third step, a part of the first measurement range is based on the comparison result between the peak point and the target point measured by the measurement process for the first point, and the specific relationship. An excluded area that is an area is identified. The exclusion region is a region where the target point cannot be included in a corresponding peak region. In the more preferable aspect, one or more areas of the plurality of measurement areas determined in the first step are specified as the exclusion area. In each of the one or more regions, the target point cannot be included in the corresponding peak region.

  Hereinafter, a specific method for specifying the exclusion region in the more preferable embodiment will be described. First, a case will be described in which the specific relationship is a relationship in which the peak position moves only to the advance side regardless of which of the plurality of transient correction parameters increases. In this case, the peak position corresponding to the peak point measured by the measurement process for the first point in the second step is more retarded (advanced side) than the peak position corresponding to the target point. When all of the plurality of transient correction parameters corresponding to the point among the plurality of measurement points whose contours have been determined in the first step are not more than the value corresponding to the first point. One or more of the measurement areas configured only by the points that are (or more) are specified. This is because, due to the specific relationship, the peak region corresponding to the measurement region where all of the plurality of transient correction parameters are equal to or less than (or greater than) the value corresponding to the first point cannot include the target point. based on.

  Next, the case where the specific relationship is a relationship in which the peak position moves only to the retard side regardless of which of the plurality of transient correction parameters increases will be described. Also in this case, based on the same idea as described above, the peak position corresponding to the peak point measured by the measurement process for the first point in the second step is more than the peak position corresponding to the target point. When the angle is on the retard side (advance side), all of the plurality of transient correction parameters corresponding to the point among the plurality of measurement points whose contours are determined in the first step are used as the exclusion region. The measurement region constituted only by points that are greater than or equal to (less than) the value corresponding to the first point is specified.

  Next, the fourth step will be described. In the fourth step, the peak point measured by the measurement process by performing the measurement process on one measurement point included in the area excluding the inside of the exclusion area in the first measurement range and the target Obtaining a comparison result with a point is repeated at least once or more while sequentially changing the measurement points to be subjected to the measurement process. In the more preferable aspect, the points excluding the points constituting the outline of only the first point and the exclusion region among the plurality of measurement points determined in the first step as the measurement points to be subjected to the measurement process. Is selected.

  Next, the fifth step will be described. In the fifth step, based on the one or more comparison results acquired in the fourth step, a second measurement range that is a region included in a region excluding the exclusion region in the first measurement range is Identified. The second measurement range is a region where the target point is included in a corresponding peak region. In the more preferable aspect, as the second measurement range, one of the remaining measurement areas excluding the exclusion area among the plurality of measurement areas determined in the first step is specified.

  Next, the sixth step will be described. In the sixth step, the correspondence between the measurement points and the peak points obtained by performing the measurement processing on each of the plurality of measurement points included in the second measurement range, the target points, and a predetermined analysis And the plurality of transient correction parameters are adapted based on the method. This adaptation is performed by identifying a point where the peak point obtained by performing the measurement process on the point matches the target point.

  In the more preferable aspect, as the correspondence, among the plurality of measurement points determined in the first step included in the second measurement range, the measurement process is already the target in the second and fourth steps. Only a first correspondence between the measurement point and the peak point for a point that is present may be used. Alternatively, as the correspondence relationship, in addition to the first correspondence relationship, among the plurality of measurement points determined in the first step constituting the contour of the second measurement range, it is still the target of the measurement process. A second correspondence relationship between the measurement point and the peak point obtained by performing the measurement process on each of one or more measurement points included in the second measurement range including a non-existing point may be used.

  As described above, in the method for adapting the transient correction parameter according to the present invention, the measurement range in which the target point is included in the corresponding peak region is a part of the first measurement range (accordingly, from the first measurement range). A second measurement range is specified, and the transient correction parameter is adapted based on the result of the measurement process (for a plurality of measurement points included in the second measurement range) for the second measurement range (therefore, Identification) is performed (the sixth step). Here, generally, when identification using the predetermined analysis method is performed, the narrower the peak region that includes the target point, and thus the narrower the measurement range corresponding to the peak region, the more the identification (ie, peak point). The accuracy of the process of identifying measurement points for matching the target point with the target point is improved. Therefore, it is possible to adapt the transient correction parameter with higher accuracy than when the transient correction parameter is adapted based on the result of the measurement process for the first measurement range.

  In addition, when the second measurement range is specified, the exclusion region is specified using the specific relationship, and the exclusion region can be excluded in advance from the second measurement range candidates (the third to fifth items). Process). In other words, the measurement range to be subjected to the measurement process performed for specifying the second measurement range can be narrowed by this exclusion region. As a result, it is possible to reduce the number of repetitions of the measurement process required for specifying the second measurement range, and therefore reduce the man-hours required for specifying the second measurement range. As a result, the man-hour required for adapting the transient correction parameter can be reduced. As described above, according to the method for adapting the transient correction parameter according to the present invention, it is possible to accurately adapt the transient correction parameter for correcting the steady adaptive injection pattern in the (specific) transient operation state and reduce the man-hour required for the adaptation. .

  Next, a fuel injection pattern determination device for an internal combustion engine according to the present invention will be described. In this apparatus, when the transient operation state in which the “difference amount in the intake oxygen concentration” is a predetermined reference amount is adopted as the “specific transient operation state”, the plurality of the above-described adaptation methods according to the present invention are adopted. Transient correction parameters are used. This apparatus includes the following means.

  The operating state parameter acquisition means acquires a predetermined operating state parameter representing the operating state of the internal combustion engine. Examples of the operation state parameter include an injection amount (when main injection and pilot injection are performed, the sum of the main injection amount and the pilot injection amount), an operation speed, and the like.

  The steady adaptive injection pattern determining means is based on the current operating state parameter and a predetermined relationship (table, map, etc.) between the operating state parameter and the steady adaptive injection pattern. A steady adaptive injection pattern corresponding to the parameter is determined. Examples of the injection pattern include an injection amount and an injection timing.

  The steady adaptive intake oxygen concentration determining means is based on the current operation state parameter and a predetermined relationship (table, map, etc.) between the operation state parameter and the steady compatible intake oxygen concentration. A steady-state adaptive inspiratory oxygen concentration corresponding to the operating state parameter is determined.

  The difference amount calculation means is configured to calculate a difference amount between the above-described “steady adaptive intake oxygen concentration corresponding to the current operating state parameter” and the intake oxygen concentration measured at the present time (that is, the “difference amount of the intake oxygen concentration”). ) Is calculated.

  The specific transient correction parameter determining means is based on the current operation state parameter, and a predetermined relationship between the operation state parameter and the plurality of transient correction parameters that are preliminarily adapted using the adaptation method, The plurality of transient correction parameters (a plurality of specific transient correction parameters) in the specific transient operation state corresponding to the current operation state parameter are determined.

  The final transient correction parameter calculation means calculates the current operation state parameter based on the above-described “difference amount of intake oxygen concentration” and the above-mentioned “a plurality of specific transient correction parameters corresponding to the current operation state parameter”. The final plurality of transient correction parameters (multiple final transient correction parameters) corresponding to the above are calculated.

  Then, the fuel injection pattern determining means corrects the above-mentioned “steady adaptive injection pattern corresponding to the current operating state parameter” with the above-described “multiple final transient correction parameters corresponding to the current operating state parameter”. The fuel injection pattern corresponding to the current operating state parameter is determined.

  As described above, the fuel injection pattern is determined by correcting the steady adaptive injection pattern by the “plurality of final transient correction parameters” calculated based on the “difference amount of the intake oxygen concentration” and the “plurality of specific transient correction parameters”. Is done. Therefore, even if the current operation state is in a transient operation state different from the specific transient operation state, the peak point can be accurately matched with the target point corresponding to the current operation state parameter. As a result, in transient operation conditions, misfire suppression and sufficient output torque are ensured regardless of the degree of transient (injection amount and operating speed change gradients, specifically "difference in intake oxygen concentration"). In addition, it is possible to stably obtain the optimum combustion state in consideration of the viewpoint of suppressing the increase in combustion noise.

  First, a fuel injection pattern determination device for an internal combustion engine (diesel engine) according to the present invention will be described.

  FIG. 1 shows a schematic configuration of a whole system in which a fuel injection pattern determination device according to an embodiment of the present invention is applied to a four-cylinder diesel engine 10. This system includes an engine main body 20 including a fuel supply system, an intake system 30 for introducing gas into a combustion chamber (in a cylinder) of each cylinder of the engine main body 20, and an exhaust system for discharging exhaust gas from the engine main body 20. 40, an EGR device 50 for performing exhaust gas recirculation, and an electric control device 60.

  A fuel injection valve (injection valve, injector) 21 is disposed above each cylinder of the engine body 20. Each fuel injection valve 21 is connected to a fuel injection pump 22 connected to a fuel tank (not shown) via a fuel pipe 23. The fuel injection pump 22 is electrically connected to the electric control device 60 so that the pressure (rail pressure) of the fuel injected from each fuel injection valve 21 can be adjusted by a drive signal from the electric control device 60. It has become. Each fuel injection valve 21 is electrically connected to the electric control device 60 and adjusts the amount of fuel injected from each fuel injection valve 21 (fuel injection amount) by a drive signal from the electric control device 60. It can be done.

  The intake system 30 includes an intake manifold 31 connected to a combustion chamber of each cylinder of the engine body 20, an intake pipe 32 connected to an upstream side assembly of the intake manifold 31 and constituting an intake passage together with the intake manifold 31, an intake pipe The throttle valve 33 rotatably held in the valve 32, the throttle valve actuator 33a for rotating the throttle valve 33 in response to the drive signal from the electric control device 60, and the intake pipe 32 are provided upstream of the throttle valve 33 in this order. The mounted intercooler 34, the compressor 35a of the supercharger 35, and the air cleaner 36 disposed at the tip of the intake pipe 32 are included.

  The exhaust system 40 includes an exhaust manifold 41 connected to each cylinder of the engine body 20, an exhaust pipe 42 connected to a downstream gathering portion of the exhaust manifold 41, and a turbine of the supercharger 35 disposed in the exhaust pipe 42. 35b, and a diesel particulate filter (DPNR) 43 interposed in the exhaust pipe 42. The exhaust manifold 41 and the exhaust pipe 42 constitute an exhaust passage.

  The EGR device 50 includes an exhaust recirculation pipe 51 that constitutes a passage for recirculating exhaust gas (EGR passage), an EGR control valve 52 interposed in the exhaust recirculation pipe 51, and an EGR cooler 53. The exhaust gas recirculation pipe 51 communicates the upstream exhaust passage (exhaust manifold 41) of the turbine 35b and the downstream intake passage (intake manifold 31) of the throttle valve 33. The EGR control valve 52 can change the exhaust gas amount (exhaust gas recirculation amount, EGR gas flow rate, EGR rate) recirculated in response to a drive signal from the electric control device 60. In the present example, the EGR rate refers to the ratio of the EGR gas flow rate to the total gas flow rate (fresh air flow rate + EGR gas flow rate) flowing into the combustion chamber.

  The electric control device 60 includes a CPU 61 connected by a bus, a ROM 62, a RAM 63, a backup RAM 64, and an interface 65 including an AD converter that store programs executed by the CPU 61, tables (maps), constants, and the like in advance. It is a computer.

  The interface 65 is connected to a hot-wire air flow meter 71, a throttle valve opening sensor 72, an intake oxygen concentration sensor 73, a crank position sensor 74, an accelerator opening sensor 75, an EGR control valve opening sensor 76, and a water temperature sensor 77. Thus, signals from these sensors are supplied to the CPU 61.

  The interface 65 is connected to the fuel injection valve 21, the fuel injection pump 22, the throttle valve actuator 33a, and the EGR control valve 52, and sends drive signals to these in accordance with instructions from the CPU 61. Yes.

  The hot-wire air flow meter 71 measures the mass flow rate of intake air (intake air (fresh air) amount per unit time) passing through the intake passage. The throttle valve opening sensor 72 detects the opening of the throttle valve 33. The intake oxygen concentration sensor 73 is a concentration of oxygen (intake air) contained in the gas in the intake passage downstream of the merging point between the intake manifold 31 and the exhaust gas recirculation pipe 51 (accordingly, the gas drawn into the combustion chamber of the engine 10). The oxygen concentration 02) is detected.

  The crank position sensor 74 detects an engine rotation speed NE that is the rotation speed of the engine 10 together with the actual crank angle. The accelerator opening sensor 75 detects the operation amount of the accelerator pedal AP (accelerator pedal operation amount Accp). The EGR control valve opening sensor 76 detects the opening of the EGR control valve 52 (EGR control valve opening θegr). The water temperature sensor 77 detects the temperature of the cooling water (cooling water temperature THW).

(Determination of fuel injection pattern)
Next, a method for determining a fuel injection pattern by the fuel injection pattern determining apparatus (hereinafter referred to as “this apparatus”) configured as described above will be described with reference to FIG. 2 which is a functional block diagram. As shown in FIG. 2, the apparatus includes means B1 to B7.

  The total injection amount determination means B1 is based on the engine speed NE, the accelerator pedal operation amount Accp, and the current operating state based on a table prepared in advance for determining the total injection amount Q using NE and Accp as arguments. A total injection amount Q (command value) corresponding to (operating state parameters NE, Accp) is determined. In this example, pilot injection is performed in the compression stroke prior to main injection near the compression top dead center. Accordingly, the total injection amount Q is the sum of the main injection amount (main injection amount) and the pilot injection amount (pilot injection amount).

  Based on the determined total injection amount Q, the engine rotational speed NE, and a table prepared in advance for determining a steady adaptive injection pattern with Q and NE as arguments, the steady adaptive injection pattern determining means B2 The steady adaptive injection pattern corresponding to the operation state (operation state parameters Q, NE) at is determined. Specifically, as the steady adaptive injection pattern, the injection timing and injection amount for pilot injection, the steady adaptive pilot injection timing Injstdp and the steady adaptive pilot injection amount Qstdp, and the injection timing and injection amount for main injection are used. Then, the steady compatible main injection timing Injstdm and the steady compatible main injection amount Qstdm are determined. Here, Q = Qstdp + Qstdm is established.

  The steady adaptive injection pattern is a peak (peak point, see FIG. 5 to be described later) in “change characteristics of heat generation rate in the combustion chamber with respect to the progress of the crank angle” in a steady operation state (Q and NE are constant). This is an injection pattern obtained by adapting the injection pattern and the EGR control valve opening so as to coincide with the target point corresponding to the operating state (combination of Q and NE). Hereinafter, the magnitude of the heat release rate and the crank angle corresponding to the peak point are also referred to as “peak height” and “peak position”, respectively. The “change characteristic of the heat generation rate in the combustion chamber with respect to the progress of the crank angle” can be obtained by using one of the well-known methods, and based on this change characteristic, the peak point (peak height and peak Position).

  The above target point corresponding to the operating state (combination of Q and NE) takes into consideration such aspects as suppressing misfire, securing sufficient output torque, and suppressing increase in combustion noise in the operating state (combination of Q and NE). The peak point corresponding to the state where the optimum combustion state is obtained above. The above table for determining the steady adaptive injection pattern is the injection pattern and EGR control so that the peak point coincides with the target point corresponding to the operation state (combination of Q and NE) in the steady operation state (Q and NE are constant). It can be created by repeatedly performing an experiment that matches the valve opening while variously changing the combination of Q and NE.

  In the steady adaptive intake oxygen concentration determining means B3, based on the determined total injection amount Q, the engine rotational speed NE, and a table prepared in advance for determining the steady adaptive intake oxygen concentration O2std using Q and NE as arguments. Thus, the steady adaptive intake oxygen concentration O2std corresponding to the current operation state (operation state parameters Q, NE) is determined.

  The steady-state adapted intake oxygen concentration O2std is an injection pattern and an EGR control valve so that the peak point coincides with the target point corresponding to the operation state (combination of Q and NE) in the steady operation state (Q and NE are constant). It is the intake oxygen concentration in a state where the opening degree is adapted. The table for determining the steady adaptive intake oxygen concentration O2std shows the injection pattern and the EGR control valve opening in the steady operation state (Q and NE are constant) during the experiment in which the injection pattern and the EGR control valve opening described above are adapted. Can be produced by repeatedly executing the process of detecting the inspiratory oxygen concentration in a state in which the combination of Q and NE is changed.

  The intake oxygen concentration difference calculation means B4 subtracts the current intake oxygen concentration O2 detected by the intake oxygen concentration sensor 73 from the determined steady-adapted intake oxygen concentration O2std to thereby determine the intake oxygen concentration difference ΔO2 (= (O2std−O2) / O2std, unit:%) is calculated. As will be described later, the intake oxygen concentration difference amount ΔO2 represents the degree of transient in the transient operation state (which can be expressed by a change gradient of the injection amount and the engine rotation speed).

  In the specific transient correction parameter determination means B5, based on the determined total injection amount Q, the engine speed NE, and a table prepared in advance for determining specific transient correction parameters using Q and NE as arguments, A specific transient correction parameter corresponding to the operation state (combination of Q and NE) is determined. Specifically, the pilot increase amount Δqp and the main advance angle amount Δinj are determined as specific transient correction parameters. The pilot increase amount Δqp is an increase amount from Qstdp for correcting the pilot injection amount from the stationary adaptive pilot injection amount Qstdp. The main advance angle amount Δinj is an advance angle amount from Injstdm for correcting the injection timing of the main injection from the steady-adapted main injection timing Injstdm.

  The specific transient correction parameter is the current operating state (combination of Q and NE) at the peak point in the transient operating state where the difference in intake oxygen concentration ΔO2 = 1% (hereinafter referred to as “specific transient operating state”) Is a parameter for correcting the injection pattern from the steady adaptive injection pattern so as to coincide with the target point corresponding to. Therefore, the specific transient correction parameters (Δqp, Δinj) are values that correlate with the peak height and the peak position. The specific transient correction parameter for each operation state (combination of Q and NE) is determined by being adapted to be described in detail later for each operation state (combination of Q and NE). The table for determining the specific transient correction parameter can be created by collecting the adaptation results of the specific transient correction parameter for each operating state (combination of Q and NE).

  In the final transient correction parameter calculation means B6, the final transient correction parameter is calculated by multiplying the determined specific transient correction parameter (Δqp, Δinj) by the calculated intake oxygen concentration difference ΔO2 (unit:%). The Specifically, the final pilot increase ΔQp (= Δqp · ΔO2) and the final main advance amount ΔInj (= Δinj · ΔO2) are calculated as the final transient correction parameters.

  The final transient correction parameter is to correct the injection pattern from the steady adaptive injection pattern so that the peak point in the current transient operation state matches the target point corresponding to the current operation state (combination of Q and NE). Parameter. The reason why the final transient correction parameter is calculated in this way is that it is known that the intake oxygen concentration difference ΔO2 indicating the degree of transient in the transient operation state and the value of the final transient correction parameter are substantially proportional. Based.

  In the final injection pattern determination means B7, the final injection pattern is determined by correcting the determined steady adaptive injection pattern with the calculated final transient correction parameter. As a specific final injection pattern, the final pilot injection timing Injfinp is determined when the final main advance amount ΔInj is advanced from the steady-fit pilot injection timing Injstdp, and the final pilot injection amount Qfinp finally reaches the steady-fit pilot injection amount Qstdp. The value is determined by adding the pilot increase ΔQp (Qstdp + ΔQp). The final main injection timing Injfinm is determined to be a time when the final main advance amount ΔInj is advanced from the steady adaptive main injection timing Injstdm, and the final main injection amount Qfinm is a value obtained by subtracting the final pilot increase ΔQp from the steady adaptive main injection amount Qstdm ( Qstdm−ΔQp). As a result, the total injection amount and the “interval between pilot injection timing and main injection timing” do not change between the steady adaptive injection pattern and the final injection pattern. The above is the outline of the method for determining the fuel injection pattern by the present apparatus.

  The final injection pattern determined by the final injection pattern determination means B7 is transmitted to the fuel injection valve 21 by the CPU 61. Thus, fuel is injected from the fuel injection valve 21 for the cylinder that is the target of fuel injection with this final injection pattern (that is, pilot injection and main injection are performed).

  In this device, the opening degree of the EGR control valve 52 (EGR control valve opening degree θegr) is set to the current operation state (combination of Q and NE) regardless of whether the operation state is a steady operation state or a transient operation state. ) Is feedback-controlled so as to coincide with the steady-fit EGR control valve opening θegrstd corresponding to Here, the steady adaptive EGR control valve opening degree θegrstd is such that the peak point coincides with the target point corresponding to the current operation state (combination of Q and NE) in the steady operation state (Q and NE are constant). And the EGR control valve opening obtained by adapting the injection pattern and the EGR control valve opening as described above. Therefore, the steady adaptive EGR control valve opening degree θegrstd changes according to the operating state (combination of Q and NE).

  In the steady operation state (Q and NE are constant), the current intake oxygen concentration O2 detected by the intake oxygen concentration sensor 73 is the steady adaptive intake oxygen concentration corresponding to the current operation state (combination of Q and NE). Since it coincides with O2std, the intake oxygen concentration difference ΔO2 = 0 (unit:%). Therefore, the final transient correction parameter becomes zero (ΔQp = 0, ΔInj = 0 °), and the final injection pattern matches the steady adaptive injection pattern corresponding to the current operating state (combination of Q and NE). As a result, fuel is injected with a steady-fit injection pattern corresponding to the current operating state (combination of Q and NE), and as a result, the peak point corresponds to the current operating state (combination of Q and NE). Match the target point. In other words, an optimal combustion state can be obtained in consideration of the misfire suppression, ensuring sufficient output torque, and suppressing increase in combustion noise.

  The solid line shown in FIG. 5 (a) indicates that “a peak point in a certain steady operation state (combination of Q and NE) coincides with a target point corresponding to the operation state (combination of Q and NE). An example of “change characteristic of heat generation rate in combustion chamber with respect to progress of crank angle” is shown.

  On the other hand, in the transient operation state (Q and NE are changing), the current intake oxygen concentration O2 detected by the intake oxygen concentration sensor 73 corresponds to the steady operation corresponding to the current operation state (combination of Q and NE). It does not coincide with the intake oxygen concentration O2std, and the intake oxygen concentration difference amount ΔO2 ≠ 0 (unit:%). Hereafter, this point is added.

  As shown in FIG. 3, when the engine rotational speed NE is constant at a certain value, when the total injection amount Q = Qa, Qb (Qa <Qb), the steady adaptive EGR control valve opening θegrstd = a, Let b be (a> b). In this case, the larger the EGR control valve opening, the smaller the intake oxygen concentration, so that when Q = Qa and QB, the steady adaptive intake oxygen concentration O2std = c and d respectively (c <d). .

  As shown in FIG. 4, when the total injection amount Q = Qa is in a steady operation state before time t1, Q increases stepwise from Qa to Qb at time t1 (thus, NE also increases after time t1). Let us consider the case where a transient operating condition occurs. In this case, as shown in FIG. 4, at time t1, the steady adaptive EGR control valve opening degree θegrstd decreases stepwise from a to b, and the steady adaptive intake oxygen concentration O2std increases step by step from c to d. To increase.

  Here, if the responsiveness of the actuator that controls the opening degree of the EGR control valve 52 is very high, the steady-fit EGR control valve opening degree θegrstd decreases stepwise from a to b at time t1. Accordingly, the actual EGR control valve opening degree θegr can also be decreased stepwise from a to b. That is, θegr can always coincide with θegrstd.

  On the other hand, even if the steady adaptive intake oxygen concentration O2std increases stepwise from c to d at time t1, the actual intake oxygen concentration O2 cannot increase stepwise from c to d at time t1. After time t1, it follows 02std with a certain delay (approaching gradually from c to d, see the broken line in FIG. 4). This is because a predetermined time is required for the gas that has passed through the EGR control valve 52 to reach the vicinity of the intake oxygen concentration sensor 73, and the intake air concentration sensor 73 detects a change in θegr. Based on the fact that it cannot immediately appear as a change in oxygen concentration O2. As a result, a period of ΔO2> 0 occurs after time t1.

  Thus, ΔO2 ≠ 0 (unit:%) can be obtained in the transient operation state. Here, since the combustion speed can change depending on the intake oxygen concentration, the peak point affected by the combustion speed can also move depending on the intake oxygen concentration. Therefore, as shown by the broken line in FIG. 5A, in the transient operation state, when the fuel is injected with the steady adaptive injection pattern corresponding to the current operation state (combination of Q and NE), the peak point is Optimum considering the viewpoints such as misfire suppression, securing of sufficient output torque, and suppression of combustion noise increase, shifting from the target point (= solid line peak point) corresponding to the operating state (combination of Q and NE) A proper combustion state cannot be obtained.

  On the other hand, in the present apparatus, in the transient operation state (ΔO2 ≠ 0), the stationary adaptive injection pattern corresponding to the current operation state (combination of Q and NE) is the final transient correction parameter (ΔQp, ΔInj) described above. Fuel is injected with an injection pattern obtained by correction. As a result, as shown by a broken line in FIG. 5B, even in the transient operation state, the peak point can coincide with the target point corresponding to the current operation state (combination of Q and NE).

  The final transient correction parameters (ΔQp, ΔInj) are set to the specific transient correction parameters (Δqp, Δinj) adapted in the specific transient operation state where ΔO2 = 1%, and the intake oxygen concentration difference amount ΔO2 (unit:%) is added. Calculated by multiplying. This is based on the fact that, as described above, it is known that the intake oxygen concentration difference ΔO2 indicating the degree of transient in the transient operation state and the value of the final transient correction parameters (ΔQp, ΔInj) are in a substantially proportional relationship. . As a result, even if the current operation state is in a transient operation state (ΔO2 ≠ 1%) different from the specific transient operation state, the peak point corresponds to the current operation state (combination of Q and NE) Can match. That is, regardless of the degree of transient (ie, the magnitude of ΔO2), it is possible to stably obtain the optimum combustion state considering the misfire suppression, ensuring sufficient output torque, and suppressing the increase in combustion noise. it can.

(Adaptation of specific transient correction parameters)
Next, a method for adapting the specific transient correction parameters (specifically, the pilot increase amount Δqp and the main advance angle amount Δinj) determined by the specific transient correction parameter determination unit B5 described above according to the present invention will be described.

  Hereinafter, a point corresponding to a combination of the pilot increase amount and the main advance angle amount will be referred to as a “measurement point”, and a range (area) represented by the combination of the pilot increase amount and the main advance angle amount will be referred to as a “measurement range (area)”. ".

  Further, based on the combination of the pilot increase corresponding to a certain measurement point and the main advance angle amount, the steady injection pattern is corrected to determine the measurement injection pattern in the same manner as the final injection pattern determination means B7 described above, Fuel is actually injected with the above-mentioned measurement injection pattern in the above-mentioned specific transient operation state (ΔO2 = 1%) obtained by actually operating the diesel engine 10, and “heat generation in the combustion chamber with respect to the progress of the crank angle” The process of acquiring the “rate change characteristic” and measuring the peak point based on the acquired change characteristic is referred to as “measurement process” for the measurement point. Therefore, this “measurement process” can also be referred to as a process for obtaining “correspondence between measurement points and peak points”.

  In addition, a region in which a contour is formed by a plurality of peak points obtained by performing “measurement processing” on a plurality of measurement points constituting a contour of a certain measurement range (region) (combination of peak position and peak height) Is referred to as a “peak region” corresponding to the measurement range (measurement region).

  In the fitting method according to the present invention, a peak response point is obtained from a plurality of “correspondences between measurement points and peak points” and target points by using a secondary response surface analysis method which is one of well-known analysis methods. A measurement point (identification point) for matching with the target point is identified. The pilot increase amount and the main advance angle amount corresponding to the identification point are respectively the pilot increase amount Δqp and the main advance angle amount Δinj that are adapted.

  When this secondary response surface analysis method is used, at least six “correspondences between measurement points and peak points” are required. Here, as the number of “correspondences between measurement points and peak points” increases, the identification point identification accuracy improves. On the other hand, a large number of “correspondences between measurement points and peak points” means that the number of “measurement processes” to be executed is large, and therefore, the number of man-hours required for adapting a specific transient correction parameter is large. . As described above, in this example, nine “correspondences between measurement points and peak points” are used when the secondary response surface analysis method is used. The nine “correspondences between measurement points and peak points” are obtained by executing “measurement processing” for each of the nine measurement points and measuring the nine peak points.

  As described above, the specific transient correction parameters (pilot increase Δqp and main advance angle amount Δinj) are set such that the peak point in the specific transient operation state at the current operation state (Q , NE combination) to match the target point.

  FIG. 6 shows target points corresponding to a certain operation state (Q = Q1, NE = NE1). Hereinafter, taking this operating state (Q = Q1, NE = NE1) as an example, a method for adapting a specific transient correction parameter for this operating state (Q = Q1, NE = NE1) will be described.

In FIG. 7, a range defined by a combination of a range of 0 to 3 of the pilot increase (mm ³ / st) and a range of 0 to 3 of the main advance angle (deg) is used as the measurement range (in diagonal lines). An example in which nine measurement points (measurement points 1 to 9) are arranged in this measurement range is shown. In this example, eight measurement points excluding the measurement point 5 correspond to points constituting the outline of the measurement range, and the measurement point 5 corresponds to a point inside the measurement range.

  “Measurement processing” for the operating state (Q = Q1, NE = NE1) is performed for each of the measurement points 1 to 9 shown in FIG. FIG. 8 shows an example of the distribution of nine peak points (peak points 1 to 9) obtained as a result. Here, the peak point n corresponds to the measurement point n (n: 1, 2,..., 8, 9). In FIG. 8, a region whose contour is constituted by eight peak points excluding the peak point 5 corresponds to the peak region (see the region indicated by fine dots). The target point (see black triangle) is contained within this peak region.

  As shown in FIGS. 7 and 8, in the “correspondence relationship between measurement points and peak points”, the peak height is increased even if the pilot increase is increased (1 → 4 → 7, 2 → 5 → 8, 3 → 6 → 9) Even if the main advance angle is increased (1 → 2 → 3, 4 → 5 → 6, 7 → 8 → 9), it can be increased or decreased. On the other hand, at the peak position, even if the pilot increase is increased (1 → 4 → 7, 2 → 5 → 8, 3 → 6 → 9), the main advance angle is increased (1 → 2 → 3, 4). → 5 → 6, 7 → 8 → 9), always advance. Hereinafter, the relationship that “the peak position is surely advanced regardless of whether the pilot increase amount or the main advance amount is increased” is referred to as “specific relationship”.

  The secondary response surface analysis method is applied based on nine “correspondences between measurement points and peak points” obtained from the nine measurement points shown in FIG. 7 and the nine peak points shown in FIG. 9. A predetermined empirical formula that can be expressed three-dimensionally in FIG. 10 is created. Since the creation of this empirical formula is well known, a detailed description thereof is omitted here.

  A measurement point (= identification point) for making the peak point coincide with this target point is identified from the empirical formula thus obtained and the target point shown in FIG. 6 (FIG. 8). Since this identification is also well known, detailed description thereof is omitted here. FIG. 11 shows an example of identified identification points. The pilot increase amount and the main injection amount corresponding to this identification point are the pilot increase amount Δqp and the main advance angle amount Δinj adapted to the operating state (Q = Q1, NE = NE1), respectively.

  In the adaptation method according to the present invention, the operation for adapting the specific transient correction parameters (pilot increase Δqp and main advance angle Δinj) according to the above procedure is repeatedly executed while changing the operation state (combination of Q and NE). . By collecting the adaptation results of the specific transient correction parameters for each operating state (combination of Q and NE), a table used by the specific transient correction parameter determination unit B5 described above can be created.

(Measurement range setting)
Next, the measurement range determined when using the quadratic response surface analysis method will be described. As shown in FIGS. 12 and 13 corresponding to FIGS. 7 and 8 described above, when the measurement range (see the area shown by oblique lines) is wide, the peak area (see the area shown by fine dots) is wide. Thus, the peak region easily includes the target point. Therefore, in order to make the measurement range as wide as possible, the measurement range may be determined to be a range defined by a combination of ranges from the minimum value to the maximum value of the pilot increase amount and the main advance angle amount. Hereinafter, such a measurement range is also referred to as a “first measurement range”. Here, the maximum value (minimum value) for the pilot increase amount (main advance amount) is when the value to be adapted for the pilot increase amount (main advance amount) exceeds that value (when it is below that value). It is a value determined that the steady adaptive injection pattern itself is not appropriate.

  However, in general, the wider the peak region including the target point, and thus the wider the measurement range corresponding to the peak region, the lower the accuracy of identification point identification. In addition, when the peak region is wide, for example, as shown in FIG. 13, a protruding portion in the shape of the peak region (in FIG. 13, a protruding portion with the peak point 1 as the tip) is likely to occur. If there is a projecting portion in the peak region, the accuracy of identification point identification also decreases due to this.

  On the other hand, as shown in FIGS. 14 and 15 corresponding to FIGS. 12 and 13, the measurement range is set to a range narrower than the first measurement range (hereinafter also referred to as “second measurement range”). Thus, a narrow peak region that includes the target point and does not have the above-described protruding portion can be formed. When identifying identification points based on nine “correspondences between measurement points and peak points” obtained from the nine measurement points 1 to 9 shown in FIG. 12 and the nine peak points 1 to 9 shown in FIG. In comparison, the identification points are determined based on nine “correspondences between measurement points and peak points” obtained from the nine measurement points 1 to 9 shown in FIG. 14 and the nine peak points 1 to 9 shown in FIG. The identification accuracy is higher in the case of identification.

  FIG. 16 shows the result of an experiment confirming this. The black circle shows the result of measuring and specifying the combination of the pilot increase and the main advance amount for actually operating the diesel engine to make the peak point coincide with the target point. The white triangle indicates the result of identifying the identification point according to the procedure described above with the measurement range set to the first measurement range. White squares indicate the results of identifying the identification points according to the procedure described above with the measurement range set to the second measurement range. In FIG. 16, the result about three types of driving | running states (combination of Q and NE) is shown.

  As can be understood from FIG. 16, the white square is closer to the black circle than the white triangle in all of the three types of operation states (combination of Q and NE). This means that when the measurement range is set to the second measurement range that is narrower than the first measurement range and the corresponding peak region includes the target point, compared to the case where the measurement range is set to the first measurement range, This means that the accuracy of identification point identification (and hence the accuracy of adaptation of specific transient correction parameters) is improved.

  Such a second measurement range (measurement range narrower than the first measurement range and corresponding peak region including the target point) is comprehensive for a large number of measurement points set comprehensively within the first measurement range. It can be specified by performing “measurement processing”. However, it is necessary to repeatedly execute the “measurement process” over many times, and an enormous man-hour is required to specify the second measurement range.

  In the adaptation method according to the present invention, by adopting the method described below, compared with the case where “measurement processing” is exhaustively repeated as described above, man-hours (specifically, less “measurement processing”) are reduced. The second measurement range can be specified with the number of repetitions). Hereinafter, this method will be described with reference to the flowchart shown in FIG.

  As shown in FIG. 18, first, a first measurement range is set in order to specify the second measurement range, and nine measurement points (measurement points 1 to 9) are arranged in the first measurement range. . Eight measurement points excluding the measurement point 5 correspond to points constituting the outline of the first measurement range, and the measurement point 5 corresponds to a point inside the first measurement range. The first measurement range includes a measurement area (a) in which an outline is formed by measurement points 2, 3, 5, and 6, a measurement area (b) in which an outline is formed by measurement points 1, 2, 4, and 5, From four measurement areas, a measurement area (c) whose contour is constituted by measurement points 4, 5, 7, and 8, and a measurement area (d) whose outline is constituted by measurement points 5, 6, 8, and 9 Become. In this method, any one of the four measurement areas is specified as the second measurement range.

  For convenience of explanation, peak points 1 to 9 corresponding to the measurement points 1 to 9 and peak areas (a) to (d) respectively corresponding to the measurement areas (a) to (d) are as shown in FIG. An example in which the target point is included in the peak region (d) is described. The case where the peak points 1 to 9 are arranged as shown in FIG. 19 is taken as an example. Generally, when the main advance amount increases, the peak position increases in addition to the advance of the peak position. (Refer to the solid arrows in FIGS. 18 and 19) As the pilot increase increases, the peak position decreases in addition to the advance of the peak position (see the broken arrows in FIGS. 18 and 19). ) Based on knowing strong tendency. In this example, the process proceeds according to the flow indicated by the thick line shown in FIG. 17, and the measurement region (d) (see FIG. 18) is specified as the second measurement range.

  In FIG. 19, the target point is known. On the other hand, the arrangement of the peak points 1 to 9 (accordingly, the peak areas (a) to (d)) (accordingly, the target point is included in the peak area (d)) is actually the measurement point 1. It is not possible to know about some of ˜9 unless “measurement processing” is performed. Further, in the xy orthogonal coordinate system shown in FIG. 19 where the peak position is on the x-axis and the peak height is on the y-axis, the position of the peak point n is represented by (xn, yn) (n: 1, 2, …, 8, 9). It is assumed that the position of the known target point is (x0, y0).

  Hereinafter, the details of the flow of processing indicated by the bold lines shown in FIG. 17 will be described in order. First, the “measurement process” is performed on the measurement point 5 (corresponding to the “first point”) that is a point inside the first measurement range, and the position (x5, y5) of the peak point 5 corresponding to the measurement point 5 is performed. ) Is measured. Next, the peak position x0 of the target point is compared with the peak position x5 of the peak point 5, and it is determined whether x5> x0 is satisfied (see FIG. 20).

  In this example, the peak position of the peak point 5 is more retarded than the peak position of the target point, and x5> x0 is established. Therefore, in this determination, “Yes” is determined. In view of the above-mentioned “specific relationship”, that is, the relationship that the peak position always advances (retards) regardless of which of the pilot increase amount and the main advance amount increases (decreases). This means that a measurement region (corresponding to the measurement region (b) in this example) in which both the pilot increase amount and the main advance angle amount are equal to or less than the value corresponding to the measurement point 5 can be specified as the “exclusion region”. The “excluded region” is a region where the target point cannot be included in the corresponding peak region (in this example, the peak region (b)).

  By this determination, in this example, the measurement area (b) that is the “exclusion area” is excluded in advance from the candidates for the second measurement range (the peak area (b) cannot include the target point). Therefore, at present, the peak region candidates that can include the target point are the peak regions (a), (c), and (d) excluding the peak region (b), and the second measurement range candidates are the measurement region (b ) Are the measurement areas (a), (c), and (d). In addition, when it determines with "No" by this determination, a measurement area | region (d) will be specified as an "exclusion area" based on the same reason in view of the said "specific relationship".

  Thereafter, in order to identify the peak region that includes the target point in the peak regions (a), (c), and (d), the measurement point 5 and the exclusion region (= measurement region (b) that have already been subjected to “measurement processing” are specified. )) It is necessary to execute the “measurement process” for any of the measurement points excluding at least the measurement point 1 constituting the contour. At that time, taking into account the positional relationship between the measurement regions (a), (c), and (d) shown in FIG. 18 and the positional relationship between the peak regions (a), (c), and (d) shown in FIG. Consider performing “measurement processing” from 6 or measurement points 8. For this reason, the following processing is performed.

  First, the peak height y0 of the target point is compared with the peak height y5 of the peak point 5, and it is determined whether or not y5> y0 is satisfied (see FIG. 21). In this example, since the peak height of the peak point 5 is smaller than the peak height of the target point, y5> y0 is not satisfied. Therefore, in this determination, it is determined as “No”. In view of the positional relationship between the peak areas (a), (c), and (d) shown in FIG. 19, the peak area (a) can include the target point in the peak areas (a) and (c). It means that it can be estimated that the nature is high. Therefore, whether or not the target point is included in the peak region (a) (ie, the target point is included in either the peak region (a) or the peak region (c) (d). Think about judging. If “Yes” is determined in this determination (y5> y0), whether or not the target point is included in the peak region (c) (that is, the target point is included in the peak region (c)). Or whether it is included in any of the peak areas (a) and (d)).

  In this example, in order to determine whether or not the target point is included in the peak region (a), “measurement processing” is then performed on the measurement point 6, and the peak point 6 corresponding to the measurement point 6 is determined. The position (x6, y6) is measured. Next, an expression f65 (x) representing a straight line f65 on the xy orthogonal coordinate system connecting the peak point 6 and the peak point 5 is calculated (see FIG. 22). Next, it is determined whether or not f65 (x0) <y0 is satisfied. In this example, as shown in FIG. 22, f65 (x0)> y0 is established. Therefore, in this determination, it is determined as “No”. This may mean that the peak area (a) does not include the target point. Therefore, at present, the peak region candidates that can include the target point are the peak regions (c) and (d), and the second measurement range candidates are the measurement regions (c) and (d). Therefore, it is next considered to determine whether the target point is included in the peak region (c) or the peak region (d). In addition, when it determines with "Yes" by this determination (f65 (x0) <y0), since it can mean that a peak area | region (a) includes a target point, it is a measurement area | region (a) as a 2nd measurement range. Is identified.

  In this example, in order to determine whether the target point is included in the peak region (c) or the peak region (d), a “measurement process” is then performed on the measurement point 8 to perform measurement. The position (x8, y8) of the peak point 8 corresponding to the point 8 is measured. Next, an expression f85 (x) representing a straight line f85 on the xy orthogonal coordinate system connecting the peak point 8 and the peak point 5 is calculated (see FIG. 23). Next, it is determined whether f85 (x0)> y0 is satisfied. In this example, as shown in FIG. 23, f85 (x0) <y0 is established. Therefore, in this determination, it is determined as “No”. This can mean that the peak region (d) includes the target point. Therefore, the measurement region (d) is specified as the second measurement range. In addition, when it is determined as “Yes” in this determination (f85 (x0)> y0), it can mean that the peak region (c) includes the target point, and therefore the measurement region (c) as the second measurement range. Is identified.

  According to the above procedure, in this example, as shown in FIG. 24, the measurement area (d) is specified as the second measurement range (see the area indicated by hatching). Then, nine measurement points included in the second measurement range are set, and nine “correspondences between measurement points and peak points” for the nine measurement points and the target point (x0) are set by the above-described method. , Y0) and a quadratic response surface analysis method, a measurement point (identification point) for making the peak point coincide with the target point is identified. The pilot increase amount and the main advance angle amount corresponding to the identification point are respectively the pilot increase amount Δqp and the main advance angle amount Δinj that are adapted.

  In the example shown in FIG. 24, measurement points 5, 6, 8, and 9 that have already been set and measurement points A, B, C, D, and E that have been set are used as the nine measurement points. ing. Of the nine measurement points, the measurement points 5, 6 and 8 constituting the contour of the second measurement range have already been subjected to the “measurement process”, so that it is not necessary to execute the “measurement process” again ( Performed measurement results can be diverted). On the other hand, the “measurement process” has not yet been executed for the measurement points 9, B, C, D, and E constituting the contour of the second measurement range and the measurement point A that is an internal point of the second measurement range. Therefore, it is necessary to newly execute “measurement processing”.

  Here, what should be noted in the above-described example is that the result of the “measurement process” for the measurement points 5, 6, and 8 for which the “measurement process” has been executed among the measurement points 1 to 9 that have already been set. All of them can be used for matching the pilot increase amount Δqp and the main advance amount Δinj. That is, in this case, as a result, it can be said that a useless “measurement process” has not been executed even once. On the other hand, for example, when it is determined “Yes” in the above-described determination (f85 (x0)> y0), that is, when the measurement region (c) is specified as the second measurement range, the measurement point 6 is determined. The result of the “measurement process” cannot be applied to the adjustment of the pilot increase amount Δqp and the main advance amount Δinj. However, even in this case, as a result, useless “measurement processing” can be performed only once.

  And based on nine “correspondences between measurement points and peak points” obtained from the nine measurement points shown in FIG. 24 and the nine peak points shown in FIG. 25 respectively corresponding to the nine measurement points, A quadratic response surface analysis method is applied to adapt the pilot increase Δqp and the main advance angle. Here, the “correspondence between the measurement points and the peak points” for the measurement points 5, 6 and 8 corresponds to the “first correspondence”, and the measurement points 9, A, B, C, D and E “Correspondence between measurement points and peak points” corresponds to the “second correspondence”.

  The case where the process proceeds according to the flow indicated by the thick line shown in FIG. 17 has been described. In the case of following a flow different from this, any one of the measurement areas (a) to (d) is specified as the second measurement range based on the same concept, and nine “measurement processes” of the specified second measurement range are performed. Based on the result, the pilot increase amount Δqp and the main advance amount Δinj are adapted.

  As described above, according to the adaptation method of the present invention, the measurement range in which the target point is included in the corresponding peak region is a part of the first measurement range and is narrower than the first measurement range. The second measurement range is specified, and the specific transient correction parameters (the pilot increase amount Δqp and the main advance amount Δinj) are adapted based on the results of a plurality of “measurement processes” for the second measurement range. Therefore, it is possible to adapt the transient correction parameter with higher accuracy than when the transient correction parameter is adapted based on the results of a plurality of “measurement processes” for the first measurement range.

  Furthermore, in specifying the second measurement range, the “specific relationship” that “the peak position always advances (retards) regardless of which of the pilot increase amount and the main advance angle amount increases (decreases)”. The “excluded area” is specified by use, and this “excluded area” is excluded in advance from the candidates for the second measurement range. Therefore, the measurement range to be subjected to the “measurement process” performed for specifying the second measurement range can be narrowed by the “exclusion region”. As a result, the number of repetitions of the “measurement process” required for specifying the second measurement range can be reduced, and therefore the man-hours required for specifying the second measurement range can be reduced. As a result, the man-hour required for adapting the transient correction parameter can be reduced. From the above, it is possible to accurately adapt the transient correction parameters for correcting the steady adaptive injection pattern in the (specific) transient operation state and reduce the man-hours required for the adaptation.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in the above-described embodiment, the pilot increase amount and the main advance angle amount are adopted as the “transient correction parameter”, and the peak position is determined regardless of whether the pilot increase amount or the main advance angle amount increases (decreases). Although the relationship of “advancing (retarding) is always used” is used, other parameters are adopted as the “transient correction parameter”, and either “pilot increase or main advance is increased” as the “specific relationship” The relationship that “the peak position is always retarded (advanced) even if (decrease)” may be used. Further, for example, fuel injection pressure (rail pressure) may be employed as the “transient correction parameter”.

  In the above-described embodiment, the quadratic response surface analysis method is employed as the “predetermined analysis method”, but other well-known analysis methods may be employed. In this case, the necessary “correspondence between measurement points and peak points” may be less than six.

  In addition, although the diesel engine is employed as the internal combustion engine in the above-described embodiment, a spark ignition internal combustion engine (gasoline engine) may be employed.

1 is a schematic configuration diagram of an entire system in which a fuel injection pattern determination device for an internal combustion engine according to an embodiment of the present invention is applied to a four-cylinder diesel engine. It is a functional block diagram at the time of a fuel-injection pattern being determined by the fuel-injection pattern determination apparatus of the internal combustion engine which concerns on embodiment of this invention. It is the graph which showed the relationship between a total injection amount, a steady adaptation intake oxygen concentration, and a steady adaptation EGR control valve opening degree. It is a figure for demonstrating that a difference arises between a steady adaptive intake oxygen concentration and an actual intake oxygen concentration in a transient operation state. FIG. 4 is a diagram for explaining that the peak point matches the target point even in the transient operation state by injecting the fuel with the injection pattern obtained by correcting the steady adaptive injection pattern with the transient correction parameter in the transient operation state. is there. It is the figure which showed an example of the target point represented by the combination of a peak position and a peak height. It is the figure which showed an example of the several measurement points arrange | positioned in the measurement range represented by the combination of pilot increase and main advance amount, and a measurement range. It is the figure which showed an example of the some peak point and peak area corresponding to the some measurement point and measurement range which were shown in FIG. Created by applying the quadratic response surface analysis method based on nine “correspondences between measurement points and peak points” obtained from the nine measurement points shown in FIG. 7 and the nine peak points shown in FIG. FIG. 3 is a diagram three-dimensionally expressing an empirical formula for a peak position. Created by applying the quadratic response surface analysis method based on nine “correspondences between measurement points and peak points” obtained from the nine measurement points shown in FIG. 7 and the nine peak points shown in FIG. FIG. 3 is a diagram that three-dimensionally represents an empirical formula for peak height. Secondary response surface from nine “correspondences between measurement points and peak points” obtained from the nine measurement points shown in FIG. 7 and the nine peak points shown in FIG. 8 and the target points shown in FIG. It is the figure which showed an example of the identification point identified by applying the analysis method. It is the figure which showed an example of the several measurement point arrange | positioned in the 1st measurement range represented by the combination of the pilot increase amount and the main advance angle amount, and the 1st measurement range. It is the figure which showed an example of the some peak point and peak area corresponding to the some measurement point and 1st measurement range which were shown in FIG. It is the figure which showed an example of the several measurement point arrange | positioned in the 2nd measurement range represented by the combination of pilot increase and main advance angle amount, and a 2nd measurement range. It is the figure which showed an example of the some peak point and peak area corresponding to the some measurement point and 2nd measurement range which were shown in FIG. When the measurement range is set to be a second measurement range that is narrower than the first measurement range and the corresponding peak region includes the target point, the identification point identification accuracy (accuracy of adaptation of the specific transient correction parameter) is improved. It is a figure for demonstrating. It is a flowchart for specifying the 2nd measurement range by the adaptation method of the transient correction parameter concerning the embodiment of the present invention. It is the figure which showed an example of the several measurement point arrange | positioned in a 1st measurement range and a 1st measurement range. It is the figure which showed an example of the some peak point and peak area corresponding to the some measurement point and measurement range shown in FIG. It is a figure for demonstrating the mode of the 1st determination performed in the process of the process shown by the thick line in FIG. It is a figure for demonstrating the mode of the 2nd determination performed in the process of the process shown by the thick line in FIG. It is a figure for demonstrating the mode of the 3rd determination performed in the process of the process shown by the thick line in FIG. It is a figure for demonstrating the mode of the 4th determination performed in the process of the process shown by the thick line in FIG. It is the figure which showed a mode that several measurement points were arrange | positioned within the 2nd measurement range narrower than a 1st measurement range. It is the figure which showed an example of the some peak point and peak area corresponding to the some measurement point and measurement range which were shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Fuel injection valve, 60 ... Electric control apparatus, 61 ... CPU, 73 ... Intake oxygen concentration sensor, 74 ... Crank position sensor, 75 ... Accelerator opening sensor, 76 ... EGR control valve opening sensor

Claims (6)

A plurality of transient correction parameters correlated at least with the magnitude of the heat generation rate corresponding to the peak in the change characteristic of the heat generation rate in the combustion chamber with respect to the progress of the crank angle of the internal combustion engine and the peak height and peak position as the crank angle. In the steady operation state, the steady adaptive injection pattern, which is a fuel injection pattern adapted in advance so that the peak point corresponding to the combination of the peak height and the peak position becomes the target point, even in the transient operation state, A plurality of transient correction parameters for correcting in a transient operation state so that a peak point becomes the target point. Even if any of the plurality of transient correction parameters increases, the peak position is advanced and delayed. The fuel injection of the internal combustion engine is adapted to a plurality of transient correction parameters having a specific relationship of moving only to one side of the corner side A method of adapting transient correction parameter of the pattern,
A first step of determining a first measurement range represented by a combination of the plurality of transient correction parameters;
A fuel injection pattern obtained by correcting the stationary adaptive injection pattern based on a combination of the plurality of transient correction parameters corresponding to the first point that is one of the measurement points inside the first measurement range. A measurement process is performed, which is a process of measuring the peak point based on the change characteristic of the heat release rate obtained by actually injecting fuel in a specific transient operation state where the degree of transient becomes a predetermined reference level. A second step;
Based on the comparison result between the peak point and the target point measured by the measurement process for the first point, and the specific relationship, a part of the first measurement range, An area in which the target point cannot be included in a peak area in which a contour is constituted by a plurality of peak points respectively measured by the measurement processing for a plurality of measurement points constituting the outline of the area is defined as an excluded area A third step to identify;
A comparison result between the peak point and the target point measured by the measurement process by performing the measurement process on one measurement point included in an area excluding the inside of the exclusion area in the first measurement range Acquiring a fourth step that is repeated at least once while sequentially changing the measurement points to be measured.
Based on one or more of the comparison results acquired in the fourth step, the target is included in the peak region corresponding to a region included in the region excluding the exclusion region in the first measurement range. A fifth step of specifying a region in which the point is included as a second measurement range;
Based on the correspondence between the measurement point and the peak point obtained by performing the measurement process on each of a plurality of measurement points included in the second measurement range, the target point, and a predetermined analysis method A sixth step of adapting the plurality of transient correction parameters by identifying a point where the peak point measured by the measurement process for the point matches the target point;
including,
A method for adapting a transient correction parameter of a fuel injection pattern of an internal combustion engine. A plurality of transient correction parameters correlated at least with the magnitude of the heat generation rate corresponding to the peak in the change characteristic of the heat generation rate in the combustion chamber with respect to the progress of the crank angle of the internal combustion engine and the peak height and peak position as the crank angle. In the steady operation state, the steady adaptive injection pattern, which is a fuel injection pattern adapted in advance so that the peak point corresponding to the combination of the peak height and the peak position becomes the target point, even in the transient operation state, A plurality of transient correction parameters for correcting in a transient operation state so that a peak point becomes the target point. Even if any of the plurality of transient correction parameters increases, the peak position is advanced and delayed. The fuel injection of the internal combustion engine is adapted to a plurality of transient correction parameters having a specific relationship of moving only to one side of the corner side A method of adapting transient correction parameter of the pattern,
A first measurement range represented by a combination of the plurality of transient correction parameters, a plurality of measurement points included in the first measurement range and constituting an outline of the first measurement range; A plurality of measurement points including internal points, and a plurality of measurement regions obtained by dividing the first measurement range, and the outline of each measurement region is constituted by a part of the plurality of measurement points, respectively. A first step of determining a plurality of measurement areas;
For the first point that is one of the points within the first measurement range among the plurality of measurement points, the steady adaptive injection pattern is corrected based on a combination of the plurality of transient correction parameters corresponding to the point. Processing for measuring the peak point based on the change characteristic of the heat release rate obtained by actually injecting fuel in a specific transient operation state in which the degree of transient is a predetermined reference level with the fuel injection pattern obtained in this way A second step of performing the measurement process,
Based on the comparison result between the peak point measured by the measurement process for the first point and the target point, and the specific relationship, the contour of the measurement region is configured among the plurality of measurement regions. One or more regions in which the target point cannot be included in a peak region in which a contour is formed by all of the peak points respectively measured by the measurement processing for all of the plurality of measurement points to be excluded are excluded regions A third step to identify;
The peak point and the target point measured by the measurement process after performing the measurement process on one of the plurality of measurement points excluding the first point and the point constituting the outline of the exclusion region only Obtaining a comparison result with the fourth step of repeating at least once while sequentially changing the measurement points to be subjected to the measurement process;
Based on the one or more comparison results acquired in the fourth step, the target point is within the corresponding peak region among the remaining measurement regions excluding the exclusion region among the plurality of measurement regions. A fifth step of specifying the included measurement region as the second measurement range;
A first correspondence between the measurement point and the peak point for a point that is already the target of the measurement process in the second and fourth steps among the plurality of measurement points included in the second measurement range. Alternatively, it includes one or more measurement points included in the second measurement range and a point that is not yet the object of the measurement process among the plurality of measurement points constituting the contour of the second measurement range. Based on the second correspondence relationship and the first correspondence relationship between the measurement point and the peak point obtained by performing the measurement processing on each of one or more measurement points, the target point, and a predetermined analysis method. A sixth step of adapting the plurality of transient correction parameters by identifying a point where the peak point measured by the measurement process for the point matches the target point;
including,
A method for adapting a transient correction parameter of a fuel injection pattern of an internal combustion engine. The method for adapting a transient correction parameter of a fuel injection pattern of an internal combustion engine according to claim 2,
In the third step,
When the specific relationship is a relationship in which the peak position moves only to the advance side even if any of the plurality of transient correction parameters increases, the measurement process for the first point in the second step When the peak position corresponding to the peak point measured by is on the retard side with respect to the peak position corresponding to the target point, the contour is the point of the plurality of measurement points as the exclusion region The measurement region configured by only points where all of the plurality of transient correction parameters corresponding to the value are equal to or less than the value corresponding to the first point is specified, and the measurement process for the first point is performed in the second step. When the peak position corresponding to the peak point measured by is on the more advanced side than the peak position corresponding to the target point, the contour is the plurality of measurement points as the exclusion region Of the measurement region formed by only in that all the above value corresponding to the first point of the plurality of transient correction parameter corresponding to the point is identified by,
When the specific relationship is a relationship in which the peak position moves only to the retard side even if any of the plurality of transient correction parameters increases, the measurement process for the first point in the second step When the peak position corresponding to the peak point measured by is on the retard side with respect to the peak position corresponding to the target point, the contour is the point of the plurality of measurement points as the exclusion region The measurement region constituted only by points at which all of the plurality of transient correction parameters corresponding to the value are equal to or greater than the value corresponding to the first point is specified, and the measurement process for the first point is performed in the second step When the peak position corresponding to the peak point measured by is on the more advanced side than the peak position corresponding to the target point, the contour is the plurality of measurement points as the exclusion region Transient correction of the fuel injection pattern of the internal combustion engine, in which the measurement region constituted only by points where all of the plurality of transient correction parameters corresponding to the point are equal to or less than the value corresponding to the first point is specified How to adapt parameters. In the adaptation method of the transient correction parameter of the fuel injection pattern of the internal-combustion engine according to any one of claims 1 to 3,
As the stationary adaptive injection pattern, a pattern in which pilot injection is performed prior to main injection is adopted,
As the plurality of transient correction parameters, the advance amount from the timing corresponding to the steady adaptive injection pattern for correcting the injection timing of the main injection from the timing corresponding to the steady adaptive injection pattern, and the injection of the pilot injection Two parameters are employed, an increase from the amount corresponding to the steady adaptive injection pattern to correct the amount from the amount corresponding to the steady adaptive injection pattern,
The specific relationship is a relationship in which the peak position moves only to the advance side regardless of which of the advance amount of the injection timing of the main injection and the increase amount of the injection amount of the pilot injection increases.
A method for adapting a transient correction parameter of a fuel injection pattern of an internal combustion engine. In the adaptation method of the transient correction parameter of the fuel injection pattern of the internal combustion engine according to any one of claims 1 to 4,
As the specific transient operation state in the measurement process,
The amount of difference between the steady adapted intake oxygen concentration, which is the intake oxygen concentration already obtained in the steady operation state when the steady adapted injection pattern is adapted, and the measured current intake oxygen concentration is a predetermined reference amount. A method for adapting a transient correction parameter of a fuel injection pattern of an internal combustion engine in which a transient operation state is adopted. 6. A fuel injection pattern determining apparatus for an internal combustion engine, wherein a fuel injection pattern is determined using the plurality of transient correction parameters adapted using the method for adapting a transient correction parameter of a fuel injection pattern for an internal combustion engine according to claim 5. Because
An operating state parameter acquiring means for acquiring a predetermined operating state parameter representing the operating state of the internal combustion engine;
A steady adaptive injection pattern determining means for determining the steady adaptive injection pattern based on the acquired current operational state parameter and a predetermined relationship between the operational state parameter and the steady adaptive injection pattern;
Steady adaptive intake oxygen concentration determination for determining the steady adaptive intake oxygen concentration based on the acquired current operating state parameter and a predetermined relationship between the operational state parameter and the steady adaptive intake oxygen concentration Means,
A difference amount calculating means for calculating a difference amount between the determined steady-adapted intake oxygen concentration and the intake oxygen concentration measured at the present time;
The specific transient operation based on the acquired current operation state parameter and a predetermined relationship between the operation state parameter and the plurality of transient correction parameters preliminarily adapted using the adaptation method. Specific transient correction parameter determination means for determining a plurality of specific transient correction parameters that are the plurality of transient correction parameters in a state;
Final transient correction parameter calculation means for calculating a plurality of final transient correction parameters that are the final plurality of transient correction parameters based on the calculated difference amount and the determined plurality of specific transient correction parameters; ,
Fuel injection pattern determination means for determining the fuel injection pattern by correcting the determined steady adaptive injection pattern with the calculated plurality of final transient correction parameters;
A fuel injection pattern determination device for an internal combustion engine, comprising:

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