JP2006138249A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of accurately correcting fuel injection quantity and individually determining irregularity of a fuel injection means. <P>SOLUTION: An engine ECU executes a program including a step S108 for setting a learning value EFGAF in relation to total injection quantity to a learning value Err_dx in relation to fuel injection quantity from a cylinder injection injector at a time of 100% cylinder injection when selective injection ratio kpfi is zero (YES in S106), a step S114 for calculating an estimated learning value Err_px of an intake air passage injection injector based on feed back correction quantity edfirt of fuel total injection quantity, learning value thereof EFGAF and the estimated learning value Err_px of the intake air passage injection injector, and a step S122 for calculating error α×(1-kpfi)/kpfi of the estimated learning value Err_px based on the estimated learning value Err_px calculated at different selective injection ratio kpfi. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides first fuel injection means (in-cylinder injector) for injecting fuel into the cylinder and second fuel injection means (intake passage injection) for injecting fuel into the intake passage or intake port. In particular, a technique for calculating a correction value for the fuel injection amount of the second fuel injection means based on the correction value for the fuel injection amount of the first fuel injection means. About.

  An injector for injecting intake passage for injecting fuel into the engine intake passage and an in-cylinder injector for injecting fuel at all times into the engine combustion chamber, the engine load being higher than a predetermined set load There is known an internal combustion engine that stops fuel injection from the intake passage injector when the engine load is low and injects fuel from the intake passage injector when the engine load is higher than the set load.

  Even in such an internal combustion engine, the fuel injection amount may not be a desired injection amount due to deposits accumulated in the injector and individual differences during manufacture. That is, the air-fuel ratio may deviate from a desired air-fuel ratio (for example, the theoretical air-fuel ratio). In order to correct the deviation of the fuel injection amount, the fuel injection amount is corrected by feedback control of the air-fuel ratio, similarly to the internal combustion engine in which one injector is provided for one cylinder.

  Japanese Patent Laying-Open No. 3-185242 (Patent Document 1) discloses a fuel injection amount control device for an internal combustion engine that accurately corrects the fuel injection amount in an internal combustion engine having a plurality of fuel injection valves per cylinder. This fuel injection amount control device learns a value based on an output signal from a control unit that controls fuel injection from a plurality of fuel injection valves according to an operating state and an oxygen sensor provided in an exhaust system of the engine. Each learning using a learning unit for correcting the fuel injection amount, a setting unit for setting a plurality of learning regions corresponding to the use states of the plurality of fuel injection valves, and each learning value learned in each of the learning regions And a correction unit that corrects the fuel injection amount in the operation state corresponding to the region.

According to the fuel injection amount control device described in this publication, the fuel injection valve that is used in the learning area matches the fuel injection valve that is used when the fuel injection amount is corrected using the learned value. Therefore, the correction accuracy of the fuel injection amount is improved. Accordingly, the air-fuel ratio followability is improved accordingly, and exhaust emission is improved. Further, since the error from the target air-fuel ratio becomes small, even if the air-fuel ratio is set to the lean side, the possibility of misfire can be reduced and fuel efficiency can be improved.
Japanese Patent Laid-Open No. 3-185242

  However, the fuel injection amount control device described in Japanese Patent Laid-Open No. 3-185242 does not individually correct the fuel injection amounts of the in-cylinder injector and the intake passage injector. Therefore, there is a problem that the fuel injection amount may not be corrected appropriately. In addition, learning values are not separately obtained for the in-cylinder injector and the intake manifold injector. Therefore, there has been a problem that it is impossible to individually determine the abnormality of the injector.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can accurately correct the fuel injection amount. Another object of the present invention is to provide a control device for an internal combustion engine that can individually determine abnormality of the fuel injection means.

  An internal combustion engine control apparatus according to a first aspect of the present invention includes an internal combustion engine having a first fuel injection means for injecting fuel into a cylinder and a second fuel injection means for injecting fuel into an intake passage. Control the engine. In the control device, the fuel is injected only from the first fuel injection unit in the first injection region, and the fuel is injected from the first fuel injection unit and the second fuel injection unit in the second injection region. In addition, based on the control means for controlling the fuel injection means, the means for calculating the correction value of the fuel injection amount in each injection region, and the correction value of the fuel injection amount in the first injection region, the first Based on the means for calculating the correction value of the fuel injection amount of the fuel injection means, the correction value of the fuel injection amount in the second injection region, and the correction value of the fuel injection amount of the first fuel injection means, Means for calculating the correction value of the fuel injection amount of the second fuel injection means at different injection ratios of the two injection regions, and the correction value of the fuel injection amount of the second fuel injection means at different injection ratios. Based on the second fuel injector Including the means for calculating an error correction value of the fuel injection amount, based on the calculated error, and means for modifying the correction value of the fuel injection quantity of the second fuel injection mechanism.

  According to the first invention, the correction value of the fuel injection amount in the first region where the fuel is injected only from the first fuel injection means (for example, the in-cylinder injector) is calculated. Since the correction value in the first region can be regarded as the correction value of the first fuel injection unit, the correction value of the fuel injection amount of the first fuel injection unit is based on the correction value in the first region. Calculated. Further, a correction value for the fuel injection amount in the second region in which fuel is injected from the first fuel injection means and the second fuel injection means (for example, an intake passage injection injector) is calculated. Since the correction value in the second region is considered to be the sum of the correction value of the first fuel injection unit and the correction value of the second fuel injection unit, the correction value of the second region and the first fuel Based on the correction value of the injection means, the correction value of the fuel injection amount of the second fuel injection means is calculated. At this time, the correction value of the second fuel injection means is calculated at different injection ratios in the second injection region. Based on the correction value of the second fuel injection means at these different injection ratios, the error of the correction value of the second fuel injection means is calculated, and based on this error, the correction value of the second fuel injection means is calculated. Is fixed. Thereby, the fuel injection amount from the second fuel injection means can be accurately corrected. The correction value of the first fuel injection unit is calculated as a correction value in the first region. Therefore, the fuel injection amount of the first fuel injection unit and the fuel injection amount of the second fuel injection unit can be individually corrected. As a result, it is possible to provide a control device for an internal combustion engine that can accurately correct the fuel injection amount.

  The control apparatus for an internal combustion engine according to the second invention, in addition to the configuration of the first invention, determines the abnormality of the second fuel injection means by comparing the corrected correction value with a predetermined value. And a determination means.

  According to the second invention, the abnormality of the second fuel injection means can be individually determined. Thereby, the control apparatus of the internal combustion engine which can determine the abnormality of a fuel-injection means separately can be provided.

  In the control device for an internal combustion engine according to the third invention, in addition to the configuration of the second invention, the determination means is configured to provide the second fuel injection means when the corrected correction value is larger than a predetermined value. Includes means for determining that is abnormal.

  According to the third invention, it can be determined whether or not the second fuel injection means is in a lean abnormality (abnormality in which the fuel injection amount is too small).

  In the control apparatus for an internal combustion engine according to the fourth aspect of the invention, in addition to the configuration of the second aspect of the invention, the determination means is the second fuel injection means when the corrected correction value is smaller than a predetermined value. Includes means for determining that is rich abnormal.

  According to the fourth invention, it can be determined whether or not the second fuel injection means is rich abnormal (abnormality in which the fuel injection amount is excessive).

  In the control apparatus for an internal combustion engine according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the first fuel injection means is an in-cylinder injector. The second fuel injection means is an intake passage injector.

  According to a fifth aspect of the present invention, in the internal combustion engine that shares the injected fuel by separately providing the in-cylinder injector that is the first fuel injection means and the intake passage injection injector that is the second fuel injection means, It is possible to correct the injection amount with high accuracy and to determine the abnormality of the injector individually.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
FIG. 1 shows a schematic configuration diagram of an engine system controlled by an engine ECU (Electronic Control Unit) which is a control device for an internal combustion engine according to a first embodiment of the present invention. Although FIG. 1 shows an in-line four-cylinder gasoline engine as the engine, the present invention is not limited to such an engine.

  As shown in FIG. 1, the engine 10 includes four cylinders 112, and each cylinder 112 is connected to a common surge tank 30 via a corresponding intake manifold 20. The surge tank 30 is connected to an air cleaner 50 via an intake duct 40, an air flow meter 42 is disposed in the intake duct 40, and a throttle valve 70 driven by an electric motor 60 is disposed. The opening degree of throttle valve 70 is controlled based on the output signal of engine ECU 300 independently of accelerator pedal 100. On the other hand, each cylinder 112 is connected to a common exhaust manifold 80, and this exhaust manifold 80 is connected to a three-way catalytic converter 90.

  For each cylinder 112, an in-cylinder injector 110 for injecting fuel into the cylinder, and an intake passage injection injector 120 for injecting fuel into the intake port or / and the intake passage. And are provided respectively. These injectors 110 and 120 are controlled based on the output signal of engine ECU 300, respectively. The in-cylinder injectors 110 are connected to a common fuel distribution pipe 130, and this fuel distribution pipe 130 is connected to the fuel distribution pipe 130 through a check valve 140, and is driven by an engine. A high-pressure fuel pump 150 is connected. In the present embodiment, an internal combustion engine in which two injectors are separately provided will be described, but the present invention is not limited to such an internal combustion engine. For example, it may be an internal combustion engine having one injector that has both an in-cylinder injection function and an intake passage injection function.

  As shown in FIG. 1, the discharge side of the high-pressure fuel pump 150 is connected to the suction side of the high-pressure fuel pump 150 via an electromagnetic spill valve 152. When the amount of fuel supplied from the pump 150 into the fuel distribution pipe 130 is increased and the electromagnetic spill valve 152 is fully opened, the fuel supply from the high pressure fuel pump 150 to the fuel distribution pipe 130 is stopped. ing. Electromagnetic spill valve 152 is controlled based on the output signal of engine ECU 300.

  On the other hand, each intake passage injector 120 is connected to a common low-pressure fuel distribution pipe 160, and the fuel distribution pipe 160 and the high-pressure fuel pump 150 are connected to a common fuel pressure regulator 170 through an electric motor drive type. The low-pressure fuel pump 180 is connected. Further, the low pressure fuel pump 180 is connected to the fuel tank 200 via a fuel filter 190. The fuel pressure regulator 170 returns a part of the fuel discharged from the low-pressure fuel pump 180 to the fuel tank 200 when the fuel pressure of the fuel discharged from the low-pressure fuel pump 180 becomes higher than a predetermined set fuel pressure. Accordingly, the fuel pressure supplied to the intake manifold injector 120 and the fuel pressure supplied to the high-pressure fuel pump 150 are prevented from becoming higher than the set fuel pressure.

  The engine ECU 300 is composed of a digital computer, and is connected to each other via a bidirectional bus 310, a ROM (Read Only Memory) 320, a RAM (Random Access Memory) 330, a CPU (Central Processing Unit) 340, and an input port 350. And an output port 360.

  The air flow meter 42 generates an output voltage proportional to the amount of intake air, and the output voltage of the air flow meter 42 is input to the input port 350 via the A / D converter 370. A water temperature sensor 380 that generates an output voltage proportional to the engine cooling water temperature is attached to the engine 10, and the output voltage of the water temperature sensor 380 is input to the input port 350 via the A / D converter 390.

  A fuel pressure sensor 400 that generates an output voltage proportional to the fuel pressure in the fuel distribution pipe 130 is attached to the fuel distribution pipe 130, and the output voltage of the fuel pressure sensor 400 is input via the A / D converter 410. Input to port 350. The exhaust manifold 80 upstream of the three-way catalytic converter 90 is provided with an air-fuel ratio sensor 420 that generates an output voltage proportional to the oxygen concentration in the exhaust gas. The output voltage of the air-fuel ratio sensor 420 is converted into an A / D converter. It is input to the input port 350 via 430.

The air-fuel ratio sensor 420 in the engine system according to the present embodiment is a global air-fuel ratio sensor (linear air-fuel ratio sensor) that generates an output voltage proportional to the air-fuel ratio of the air-fuel mixture burned by the engine 10. The air-fuel ratio sensor 420 may be an O ₂ sensor that detects whether the air-fuel ratio of the air-fuel mixture burned in the engine 10 is rich or lean with respect to the stoichiometric air-fuel ratio. Good.

  In the present embodiment, engine ECU 300 calculates a feedback correction amount for the total fuel injection amount based on the output voltage of air-fuel ratio sensor 420. Further, when a predetermined learning condition is satisfied, a learning value of the feedback correction amount (a value representing a constant deviation amount of the fuel injection amount) is calculated. The calculation of the feedback correction amount and its learning value is performed within a predetermined learning area. The learning area will be described in detail later.

  The feedback correction amount and the method for calculating the learning value thereof may be a technique generally used in an internal combustion engine provided with one injector per cylinder, and will be described in detail here. Will not repeat.

  The accelerator pedal 100 is connected to an accelerator opening sensor 440 that generates an output voltage proportional to the depression amount of the accelerator pedal 100, and the output voltage of the accelerator opening sensor 440 is input to the input port 350 via the A / D converter 450. Is input. The input port 350 is connected to a rotational speed sensor 460 that generates an output pulse representing the engine rotational speed. In the ROM 320 of the engine ECU 300, the value of the fuel injection amount and the engine cooling that are set according to the operating state based on the engine load factor and the engine speed obtained by the accelerator opening sensor 440 and the engine speed sensor 460 described above are stored. Correction values based on the water temperature and the like are previously mapped and stored.

  Referring to FIGS. 2 and 3, the injection ratio of in-cylinder injector 110 and intake manifold injector 120 (hereinafter referred to as DI ratio (r)), which is information corresponding to the operating state of engine 10, is also referred to. Will be described). These maps are stored in the ROM 320 of the engine ECU 300. FIG. 2 is a map for the warm of the engine 10, and FIG. 3 is a map for the cold of the engine 10.

  As shown in FIG. 2 and FIG. 3, these maps are expressed in percentages where the engine 10 rotational speed is on the horizontal axis, the load factor is on the vertical axis, and the share ratio of the in-cylinder injector 110 is the DI ratio r. It is shown.

  As shown in FIGS. 2 and 3, the DI ratio r is set for each operation region determined by the rotation speed and load factor of the engine 10. “DI ratio r = 100%” means a region where fuel injection is performed only from in-cylinder injector 110, and “DI ratio r = 0%” means from intake manifold injector 120. This means that only the region where fuel injection is performed. “DI ratio r ≠ 0%”, “DI ratio r ≠ 100%” and “0% <DI ratio r <100%” indicate that in-cylinder injector 110 and intake passage injector 120 perform fuel injection. It means that the area is shared. In general, the in-cylinder injector 110 contributes to an increase in output performance, and the intake manifold injector 120 contributes to the uniformity of the air-fuel mixture. By using two types of injectors having different characteristics depending on the rotation speed and load factor of the engine 10, the engine 10 is in a normal operation state (for example, when the catalyst is warmed up at idle when the engine 10 is in an abnormal state other than the normal operation state). In this case, only homogeneous combustion is performed.

  Further, as shown in FIG. 2 and FIG. 3, the DI share ratio r of the in-cylinder injector 110 and the intake manifold injector 120 is defined by dividing it into a warm map and a cold map. did. If the temperature of the engine 10 is different, the temperature of the engine 10 is detected by detecting the temperature of the engine 10 using a map set so that the control areas of the in-cylinder injector 110 and the intake manifold injector 120 are different. If it is equal to or higher than a predetermined temperature threshold value, the warm time map shown in FIG. 2 is selected. Otherwise, the cold time map shown in FIG. 3 is selected. Based on the selected maps, the in-cylinder injector 110 and / or the intake manifold injector 120 are controlled based on the rotation speed and load factor of the engine 10.

  In the present embodiment, the fuel injection amount from in-cylinder injector 110 and the fuel from intake manifold injector 120 are based on DI ratio r so that the total fuel injection amount becomes a desired injection amount. The injection amount is determined.

  At this time, the actual fuel injection amounts from the in-cylinder injector 110 and the intake manifold injector 120 change due to the influence of accumulated deposits and individual differences during manufacturing. Therefore, a learned value Err_d for the fuel injection amount from in-cylinder injector 110 and a learned value Err_p for the fuel injection amount from intake manifold injector 120 are calculated. Engine ECU 300 corrects the fuel injection amount from each injector based on each calculated learning value. A method for calculating each learning value will be described in detail later.

  The engine speed and load factor of engine 10 set in FIGS. 2 and 3 will be described. In FIG. 2, NE (1) is set to 2500 to 2700 rpm, KL (1) is set to 30 to 50%, and KL (2) is set to 60 to 90%. Further, NE (3) in FIG. 3 is set to 2900-3100 rpm. That is, NE (1) <NE (3). In addition, NE (2) in FIG. 2 and KL (3) and KL (4) in FIG. 3 are also set as appropriate.

  When FIG. 2 and FIG. 3 are compared, NE (3) of the map for cold shown in FIG. 3 is higher than NE (1) of the map for warm shown in FIG. This indicates that as the temperature of the engine 10 is lower, the control range of the intake manifold injector 120 is expanded to a higher engine speed range. That is, since the engine 10 is in a cold state, deposits are unlikely to accumulate at the injection port of the in-cylinder injector 110 (even if fuel is not injected from the in-cylinder injector 110). For this reason, it sets so that the area | region which injects a fuel using the intake manifold injector 120 may be expanded, and a homogeneity can be improved.

  Comparing FIG. 2 and FIG. 3, in the region where the engine 10 has a rotational speed of NE (1) or higher in the warm map and in the region of NE (3) or higher in the cold map, “DI ratio r = 100% ". Further, the load factor is “DI ratio r = 100%” in the region of KL (2) or higher in the warm map and in the region of KL (4) or higher in the cold map. This indicates that only the in-cylinder injector 110 is used in a predetermined high engine speed region, and only the in-cylinder injector 110 is used in a predetermined high engine load region. . That is, in the high speed region and the high load region, even if the fuel is injected only by the in-cylinder injector 110, the engine 10 has a high rotational speed and load, and the intake amount is large. It is because it is easy to homogenize. Thus, the fuel injected from the in-cylinder injector 110 is vaporized with latent heat of vaporization (sucking heat from the combustion chamber) in the combustion chamber. Thereby, the temperature of the air-fuel mixture at the compression end is lowered. As a result, the knocking performance is improved. Further, since the temperature of the combustion chamber is lowered, the suction efficiency is improved and high output can be expected.

  In the warm map shown in FIG. 2, only the in-cylinder injector 110 is used below the load factor KL (1). This indicates that when the temperature of the engine 10 is high, only the in-cylinder injector 110 is used in a predetermined low load region. This is because when the engine 10 is warm, the engine 10 is in a warm state, and deposits are likely to accumulate at the injection port of the in-cylinder injector 110. However, since the injection port temperature can be lowered by injecting fuel using the in-cylinder injector 110, it is conceivable to avoid deposit accumulation, and the minimum fuel injection amount of the in-cylinder injector Therefore, it is conceivable that the in-cylinder injector 110 is not blocked, and for this purpose, the in-cylinder injector 110 is used.

  Comparing FIG. 2 and FIG. 3, the region of “DI ratio r = 0%” exists only in the cold map of FIG. 3. This indicates that when the temperature of the engine 10 is low, only the intake manifold injector 120 is used in a predetermined low load region (KL (3) or less). This is because the engine 10 is cold and the load on the engine 10 is low and the intake air amount is low, so that the fuel is difficult to atomize. In such a region, it is difficult to perform good combustion with the fuel injection by the in-cylinder injector 110. In particular, a high output using the in-cylinder injector 110 is required in the region of low load and low rotation speed. Therefore, only the intake passage injector 120 is used without using the in-cylinder injector 110.

  In addition, in the case other than the normal operation, the in-cylinder injector 110 is controlled so as to perform stratified combustion when the engine 10 is at the time of catalyst warm-up when idling (in a non-normal operation state). By performing stratified charge combustion only during such catalyst warm-up operation, catalyst warm-up is promoted and exhaust emission is improved.

  With reference to FIG. 4, the learning region in which the feedback correction amount edfirst and the learning value EFGAF are calculated will be described. In FIG. 4, a region sandwiched by curved lines indicated by alternate long and short dashed lines is a learning region. In the learning area, the fuel injection is performed only from the in-cylinder injector ("DI ratio r = 100%"), and the in-cylinder injector 110 and the intake manifold injector 120 perform the fuel injection. (“0% <DI ratio r <100%”).

  The learning area is set from the low load area to the medium load area of the engine 10. In other words, the learning region is set for operating conditions that are satisfied for a relatively long time. As a result, the period during which the fuel injection amount is learned can be made longer. In addition, by setting a plurality of learning areas, learning can be performed with high accuracy according to the operating conditions (load) of the engine 10. The learning area shown in FIG. 4 is an example. Therefore, the learning area is not limited to this.

  Referring to FIG. 5, a control structure of a program executed by engine ECU 300 that is a control device according to the embodiment of the present invention will be described. In the following description, instead of the DI ratio r, the injection ratio kpfi (0 ≦ kpfi ≦ 1) indicating the ratio of the fuel injection amount from the intake manifold injector 120 to the total injection amount will be described. That is, kpfi = 1−r / 100.

  In step (hereinafter, step is abbreviated as S) 100, engine ECU 300 determines the feedback correction amount and its learning value based on the engine speed detected by the output pulse of speed sensor 460 and the load factor of engine 10. A learning area is calculated. The load factor is calculated based on the engine speed.

  In S102, engine ECU 300 executes learning for the total fuel injection amount. Specifically, based on the output voltage of the air-fuel ratio sensor 420, the feedback correction amount edfirt of the total fuel injection amount is calculated, and the learning value EFGAF is calculated and updated.

  In S104, engine ECU 300 determines whether or not learning is completed. Since learning is performed by engine ECU 300, whether or not learning is completed is determined inside engine ECU 300. If learning is completed (YES in S104), the process proceeds to S106. If not (NO in S104), the process returns to S100.

  In S106, engine ECU 300 determines whether or not injection ratio kpfi is 0 based on the map stored in ROM 320. If ejection ratio kpfi is 0 (YES in S106), the process proceeds to S108. If not (NO in S106), the process proceeds to S110.

  In S108, engine ECU 300 sets learning value EFGAF for the total injection amount to learning value Err_dx for the fuel injection amount from in-cylinder injector 110 at the time of 100% in-cylinder injection. Thereafter, the process returns to S100.

  In S110, engine ECU 300 determines whether or not learning for the fuel injection amount from in-cylinder injector 110 has been completed. Since the engine ECU 300 learns the fuel injection amount from the in-cylinder injector 110, whether or not the learning is completed is determined inside the engine ECU 300. If learning is completed (YES in S110), the process proceeds to S112. If not (NO in S110), the process returns to S100.

  In S112, engine ECU 300 determines injection ratio kpfi based on the map stored in ROM 320. In S114, engine ECU 300 calculates an estimated learning value Err_px for the fuel injection amount from intake manifold injector 120.

  Here, the learning value for the fuel injection amount from the in-cylinder injector 110 in the injection division region (region where 0 <kpfi <1) is Err_d, and the learning value for the fuel injection amount from the intake manifold injector 120 is the learning value. Let Err_p.

  The correction amount of the total injection amount with respect to the target injection amount (edfirst + EFGAF) is the sum of the correction amount of the in-cylinder injector 110 and the correction amount of the intake manifold injector 120. Therefore, edfirst + EFGAF = (1−kpfi) × Err_d + kpfi × Err_p. Solving this, Err_p = Err_d + (edfirst + EFGAF−Err_d) / kpfi.

  Err_d in this equation is substituted with the learned value Err_dx for the fuel injection amount from the in-cylinder injector 110 when the injection ratio kpfi = 0 (100% in-cylinder injection), and the intake manifold injector 120 is substituted. The estimated learning value Err_px for the fuel injection amount from is calculated. Therefore, Err_px = Err_dx + (edfirst + EFGAF−Err_dx) / kpfi.

  In S116, engine ECU 300 stores the calculated estimated learning value Err_px in RAM 330 in association with the learning region calculated in S100 and the injection ratio kpfi determined in S112.

  In S118, engine ECU 300 determines whether or not estimated learning value Err_px has been calculated at different injection ratios kpfi in the same learning region. Since the estimated learning value Err_px is calculated by the engine ECU 300, whether or not the estimated learning value Err_px has been calculated at different injection ratios kpfi is determined inside the engine ECU 300. If estimated learning value Err_px is calculated at a different ejection ratio kpfi (YES in S118), the process proceeds to S120. If not (NO in S118), the process returns to S100).

  In S120, engine ECU 300 calculates error α × (1−kpfi) / kpfi of estimated learning value Err_px with respect to learning value Err_p. Here, an error of the learning value Err_dx with respect to the learning value Err_d is set to α. That is, Err_dx = Err_d + α. This is substituted into Err_px = Err_dx + (edfirt + EFGAF−Err_dx) / kpfi, and Err_px = Err_d + α + (edfirt + EFGAF−Err_d−α) / kpfi.

  In summary, Err_px = Err_d + (edfirt + EFGAF−Err_d) / kpfi−α × (1−kpfi) / kpfi. Here, since Err_p = Err_d + (edfirst + EFGAF−Err_d) / kpfi, Err_px = Err_p−α × (1−kpfi) / kpfi. Therefore, the error of the estimated learning value Err_px with respect to the learning value Err_p is α × (1−kpfi) / kpfi.

  Further, the estimated learning values Err_px when the ejection ratio kpfi is kpfi (0) and kpfi (1) are set to Err_px (0) and Err_px (1), respectively. Accordingly, Err_px (0) = Err_p−α × (1−kpfi (0)) / kpfi (0). Further, Err_px (1) = Err_p−α × (1−kpfi (1)) / kpfi (1).

  From the simultaneous equations of both equations, α = (Err_px (1) −Err_px (0)) × kpfi (1) × kpfi (0) / (kpfi (1) −kpfi (0)) is obtained. Using α obtained by this equation, an error α × (1−kpfi) / kpfi of the estimated learning value Err_px with respect to the learning value Err_p is calculated.

  In S122, engine ECU 300 corrects Err_px and Err_dx using error α × (1-kpfi) / kpfi and α calculated in S120, and in the injection region (region where 0 <kpfi <1). A learning value (Err_p, Err_d) of each injector is calculated.

  The operation of engine ECU 300 that is the control device for the internal combustion engine according to the present embodiment based on the above-described structure and flowchart will be described.

  During the operation of the engine 100, a feedback correction amount and a learning region for the learned value are calculated based on the engine speed detected by the output pulse of the speed sensor 460 and the load factor of the engine 10 (S100). In this learning region, learning for the total fuel injection amount is executed (S102). By executing the learning, the feedback correction amount edfirst of the total fuel injection amount and the learning value EFGAF are calculated and updated.

  When the learning is completed (YES in S104), it is determined whether or not the ejection ratio kpfi is 0 based on the map stored in the ROM 320 (S106). If injection ratio kpfi is 0 (YES in S106), learning value EFGAF for the total injection amount is set to learning value Err_dx for the fuel injection amount from in-cylinder injector 110 at the time of 100% in-cylinder injection. (S108).

  If the injection ratio kpfi is not 0 (NO in S106), if learning with respect to the fuel injection amount from in-cylinder injector 110 is completed (YES in S110), it is based on the map stored in ROM 320. Thus, the spray distribution rate kpfi is determined (S112).

  Here, it is assumed that the spray distribution ratio kpfi is kpfi (0). In this case, the estimated learning value Err_px (0) for the fuel injection amount from the intake manifold injector 120 at the injection ratio kpfi (0) is calculated as Err_px (0) = Err_dx + (edfirt + EFGAF−Err_dx) / kpfi (0). (S114). That is, the estimated learning value Err_px is calculated based on the feedback correction amount edfirt of the total fuel injection amount, the learning value EFGAF, and the learning value Err_dx of the in-cylinder injector 110. The calculated estimated learning value Err_px (0) is stored in the RAM 330 corresponding to the ejection ratio kpfi (0) (S116).

  Here, it is assumed that, in the same learning region, the estimated learning value Err_px (1) at the ejection ratio kpfi (1) is calculated (S114) and stored (S116) in addition to the ejection ratio kpfi (0). .

  Since the estimated learning value Err_px is calculated with different ejection ratios kpfi in the same learning region (YES in S118), the error α of the learning value Err_dx with respect to the learning value Err_d is α = (Err_px (1) −Err_px ( 0)) × kpfi (1) × kpfi (0) / (kpfi (1) −kpfi (0)). Based on this error α, an error α × (1−kpfi) / kpfi of the estimated learning value Err_px is calculated (S120).

  When the error is calculated, the learning value Err_dx is corrected as Err_d = Err_dx-α, and the learning value Err_d of the in-cylinder injector 110 in the injection divided region is calculated (S122). Further, the estimated learned value Err_px is corrected as Err_p = Err_px + α × (1−kpfi) / kpfi, and the learned value Err_p of the intake manifold injector 120 in the injection divided region is calculated (S122). Thereby, the learning value can be calculated systematically.

  Based on each learning value calculated in this way, the fuel injection amount from each injector is corrected. Therefore, the fuel injection amount from each injector can be corrected individually and accurately. As a result, the total fuel injection amount can be accurately corrected.

  As described above, the engine ECU of the control device for an internal combustion engine according to the present embodiment uses the learned value EFGAF in the region where fuel injection is performed only from the in-cylinder injector as the learned value Err_dx for the in-cylinder injector. Set. Based on the learning value Err_dx of the in-cylinder injector, the feedback correction amount kpfi in the region where fuel is injected from the two injectors, and the learning value EFGAF, the estimated learning value Err_px of the intake manifold injector is calculated. Based on the estimated learning value Err_px of the intake manifold injector calculated at different injection divisions kpfi, the error α of the learning value Err_dx with respect to the learning value Err_d and the error α × (1-kpfi) of the estimated learning value Err_px with respect to the learning value Err_p / Kpfi is calculated. Based on these errors, the learning values Err_d and Err_p of each injector in the injection region are calculated. Thereby, the learning value of each injector can be accurately calculated.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the abnormality of each injector is determined based on the learning value of each injector calculated in the first embodiment described above. Other structures are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  With reference to FIG. 6, a control structure of a program executed by engine ECU 300 of the control device for an internal combustion engine according to the present embodiment will be described. Engine ECU 300 executes a program described below in addition to the program of the first embodiment described above.

  In S200, engine ECU 300 determines whether or not the correction amount (Err_d + (1−kpfi) × edfirt) of the fuel injection amount from in-cylinder injector 110 in the injection divided region is greater than lean abnormality determination value FAFGDH. judge. If correction amount (Err_d + (1−kpfi) × edfirt) is larger than lean abnormality determination value FAFGDH (YES in S200), the process proceeds to S202. If not (NO in S200), the process proceeds to S204.

  In S202, engine ECU 300 determines that in-cylinder injector 110 has a lean abnormality. Note that the lean abnormality means that the correction amount is excessive, that is, the fuel injection amount is excessive.

  In S204, engine ECU 300 determines whether or not the correction amount (Err_d + (1−kpfi) × edfirt) of the fuel injection amount from in-cylinder injector 110 in the injection divided region is smaller than rich abnormality determination value FAFGDL. judge. If correction amount (Err_d + (1−kpfi) × edfirst) is smaller than rich abnormality determination value FAFGDL (YES in S204), the process proceeds to S206. If not (NO in S204), the process proceeds to S208.

  In S206, engine ECU 300 determines that in-cylinder injector 110 has a rich abnormality. The rich abnormality means that the correction amount is excessively small, that is, the fuel injection amount is excessive. In S208, engine ECU 300 determines that in-cylinder injector 110 is normal.

  In S210, engine ECU 300 determines whether or not the correction amount (Err_p + edfirt × kpfi) of the fuel injection amount from intake manifold injector 120 in the injection divided region is larger than lean abnormality determination value FAFGDH. If correction amount (Err_p + edfirt × kpfi) is larger than lean abnormality determination value FAFGDH (YES in S210), the process proceeds to S212. If not (NO in S210), the process proceeds to S214. In S212, engine ECU 300 determines that intake manifold injector 120 has a lean abnormality. Thereafter, this process ends.

  In S214, engine ECU 300 determines whether or not the correction amount (Err_p + edfirt × kpfi) of the fuel injection amount from intake manifold injector 120 in the injection divided region is smaller than rich abnormality determination value FAFGDL. If correction amount (Err_p + edfirt × kpfi) is smaller than rich abnormality determination value FAFGDL (YES in S214), the process proceeds to S216. If not (NO in S214), the process proceeds to S218.

  In S216, engine ECU 300 determines that intake manifold injector 120 is rich. Thereafter, this process ends. In S218, engine ECU 300 determines that intake manifold injector 120 is normal. Thereafter, this process ends.

  An operation of engine ECU 300 of the control device for an internal combustion engine according to the present embodiment based on the above-described structure and flowchart will be described.

  In the state where the learning values Err_d and Err_p of each injector in the injection division region are calculated, the correction amount (Err_d + (1−kpfi) × edfirt) of the fuel injection amount from the in-cylinder injector 110 in the injection division region is lean. It is determined whether or not the abnormality determination value is larger than FAFGDH (S200).

  If the correction amount (Err_d + (1−kpfi) × edfirt) is larger than the lean abnormality determination value FAFGDH (YES in S200), it can be said that the correction amount is excessive. In this case, it is determined that the in-cylinder injector 110 has a lean abnormality (S202).

  When correction amount (Err_d + (1−kpfi) × edfirt) is smaller than lean abnormality determination value FAFGDH (NO in S200), correction amount (Err_d + (1−kpfi) × edfirt) is greater than rich abnormality determination value FAFGDL. It is also determined whether or not is smaller (S204).

  If the correction amount (Err_d + (1−kpfi) × edfirst) is smaller than the rich abnormality determination value FAFGDL (YES in S204), it can be said that the correction amount is too small. In this case, it is determined that the in-cylinder injector 110 has a rich abnormality (S206).

  When it is larger than rich abnormality determination value FAFGDL (NO in S204), it can be said that correction amount (Err_d + (1-kpfi) × edfirt) is within the range of the appropriate value. In this case, it is determined that the in-cylinder injector 110 is normal (S208). Thereby, it is possible to individually determine whether or not the in-cylinder injector 110 is abnormal.

  When the abnormality determination of the in-cylinder injector 110 is completed, whether or not the correction amount (Err_p + edfirt × kpfi) of the fuel injection amount from the intake manifold injector 120 in the injection divided region is larger than the lean abnormality determination value FAFGDH. It is determined (S210).

  If the correction amount (Err_p + edfirt × kpfi) is larger than the lean abnormality determination value FAFGDH (YES in S210), it can be said that the correction amount is excessive. In this case, it is determined that the intake manifold injector 120 has a lean abnormality (S212).

  If the correction amount (Err_p + edfirt × kpfi) is smaller than the lean abnormality determination value FAFGDH (NO in S210), it is determined whether or not the correction amount (Err_p + edfirt × kpfi) is smaller than the rich abnormality determination value FAFGDL ( S214).

  If the correction amount (Err_p + edfirt × kpfi) is smaller than the rich abnormality determination value FAFGDL (YES in S214), it can be said that the correction amount is too small. In this case, it is determined that the intake manifold injector 120 is rich abnormal (S216).

  If the correction amount (Err_p + edfirt × kpfi) is larger than the rich abnormality determination value FAFGDL (NO in S214), it can be said that the correction amount (Err_p + edfirt × kpfi) is within the appropriate value range. In this case, it is determined that the intake manifold injector 120 is normal (S218). Thereby, it is possible to individually determine whether or not intake manifold injector 120 is abnormal.

  As described above, the engine ECU of the control apparatus for an internal combustion engine according to the present embodiment determines the lean abnormality determination based on the correction amount (Err_d + (1−kpfi) × edfirt) of the fuel injection amount from the in-cylinder injector. Compared with the value FAFGDH and the rich or higher determination value FAFGDH. As a result, it is possible to individually determine whether the in-cylinder injector is rich or lean. Further, the engine ECU compares the correction amount (Err_p + edfirt × kpfi) of the fuel injection amount from the intake manifold injector with the lean abnormality determination value FAFGDH and the rich abnormality determination value FAFGDH. As a result, it is possible to individually determine whether the intake manifold injector is rich or lean.

<Third Embodiment>
With reference to FIG. 7 and FIG. 8, a third embodiment of the present invention will be described. In the present embodiment, the DI ratio r (split distribution ratio kpfi) is calculated using a map different from the first and second embodiments described above.

  Other structures and processing flows are the same as those in the first or second embodiment described above. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  With reference to FIGS. 7 and 8, a map representing the injection ratio of in-cylinder injector 110 and intake manifold injector 120 that is information corresponding to the operating state of engine 10 will be described. These maps are stored in the ROM 320 of the engine ECU 300. FIG. 7 is a map for the warm of the engine 10, and FIG. 8 is a map for the cold of the engine 10.

  7 and 8 differ from FIGS. 2 and 3 in the following points. The rotational speed of the engine 10 is “DI ratio r = 100%” in the region of NE (1) or more in the warm map and in the region of NE (3) or more in the cold map. In the region where the load factor is KL (2) or higher excluding the low rotational speed region in the warm map, and in the region where KL (4) is higher than the low rotational speed region in the cold map, “DI” Ratio r = 100% ”. This is because only the in-cylinder injector 110 is used in a predetermined high engine speed region, and only the in-cylinder injector 110 is used in a predetermined high engine load region. Indicates. However, in the high load region of the low engine speed region, mixing of the air-fuel mixture formed by the fuel injected from the in-cylinder injector 110 is not good, and the air-fuel mixture in the combustion chamber is inhomogeneous and combustion is unstable. Tend to be. For this reason, the injection ratio of the in-cylinder injector is increased with the shift to the high rotation speed region where such a problem does not occur. In addition, the injection ratio of the in-cylinder injector 110 is decreased as the engine shifts to a high load region where such a problem occurs. These changes in the DI ratio r are indicated by cross arrows in FIGS. If it does in this way, the fluctuation | variation of the output torque of an engine resulting from combustion being unstable can be suppressed. It should be noted that these things can be achieved by reducing the injection ratio of the in-cylinder injector 110 as the engine shifts to the predetermined low rotational speed region, or by the in-cylinder injection as the vehicle shifts to the predetermined low load region. The fact that it is substantially equivalent to increasing the injection ratio of the injector 110 for operation will be described. Further, areas other than such areas (areas where the cross arrows are shown in FIGS. 7 and 8) and areas where fuel is injected only by the in-cylinder injector 110 (high rotation side, low load) On the other hand, it is easy to homogenize the air-fuel mixture with the in-cylinder injector 110 alone. Thus, the fuel injected from the in-cylinder injector 110 is vaporized with latent heat of vaporization (sucking heat from the combustion chamber) in the combustion chamber. Thereby, the temperature of the air-fuel mixture at the compression end is lowered. As a result, the knocking performance is improved. Further, since the temperature of the combustion chamber is lowered, the suction efficiency is improved and high output can be expected.

  In the engine 10 described in the first to third embodiments, the homogeneous combustion is performed by setting the fuel injection timing of the in-cylinder injector 110 as the intake stroke, and the stratified combustion is performed by the in-cylinder injector 110. This can be realized by setting the fuel injection timing in the compression stroke. That is, by setting the fuel injection timing of the in-cylinder injector 110 as the compression stroke, stratified combustion is realized in which the rich air-fuel mixture is unevenly distributed around the spark plug and the entire combustion chamber ignites a lean air-fuel mixture. Can do. Further, even when the fuel injection timing of the in-cylinder injector 110 is set to the intake stroke, if rich air-fuel mixture can be unevenly distributed around the spark plug, stratified combustion can be realized even with the intake stroke injection.

  Further, the stratified combustion here includes both stratified combustion and weakly stratified combustion described below. In the weak stratified combustion, the intake passage injector 120 is injected with fuel in the intake stroke to produce a lean and homogeneous mixture in the entire combustion chamber, and the in-cylinder injector 110 is injected with fuel in the compression stroke. A rich air-fuel mixture is generated around the spark plug to improve the combustion state. Such weak stratified combustion is preferable when the catalyst is warmed up. This is due to the following reason. That is, it is necessary to significantly retard the ignition timing and maintain a good combustion state (idle state) in order to allow high-temperature combustion gas to reach the catalyst during catalyst warm-up. Moreover, it is necessary to supply a certain amount of fuel. Even if this is done by stratified combustion, there is a problem that the amount of fuel is small, and even if this is done by homogeneous combustion, there is a problem that the retard amount is small compared to stratified combustion in order to maintain good combustion. is there. From such a viewpoint, it is preferable to use the above-described weak stratified combustion at the time of warming up the catalyst, but either stratified combustion or weak stratified combustion may be used.

  In the engine described in the first to third embodiments, the timing of fuel injection by the in-cylinder injector 110 is preferably performed in the compression stroke for the following reason. However, in the engine 10 described above, in a basic most region (a weak operation that is performed only when the catalyst is warmed up, the intake passage injection injector 120 is injected in the intake stroke and the in-cylinder injector 110 is compressed in the compression stroke. The timing of fuel injection by the in-cylinder injector 110 other than the stratified combustion region is a basic region) is the intake stroke. However, for the following reasons, the fuel injection timing of the in-cylinder injector 110 may be temporarily set to the compression stroke injection for the purpose of stabilizing the combustion.

  By setting the fuel injection timing from the in-cylinder injector 110 during the compression step, the air-fuel mixture is cooled by fuel injection at a time when the in-cylinder temperature is higher. Since the cooling effect is enhanced, knock resistance can be improved. Furthermore, if the fuel injection timing from the in-cylinder injector 110 is in the compression step, the time from the fuel injection to the ignition timing is short, so that the airflow can be strengthened by spraying and the combustion speed can be increased. From these improvement in knocking property and increase in combustion speed, combustion fluctuation can be avoided and combustion stability can be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram of the engine system controlled by the control apparatus which concerns on the 1st Embodiment of this invention. It is a figure showing DI ratio map at the time of warm memorized by engine ECU which is a control device concerning a 1st embodiment of the present invention. It is a figure showing the DI ratio map at the time of cold memorized by engine ECU which is a control device concerning a 1st embodiment of the present invention. It is a figure which shows the learning area | region of the fuel injection quantity memorize | stored in engine ECU which is a control apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the control structure of the program performed by engine ECU which is a control apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the control structure of the program performed by engine ECU which is a control apparatus which concerns on the 2nd Embodiment of this invention. It is a figure showing the DI ratio map at the time of warm memorize | stored in engine ECU which is a control apparatus which concerns on the 3rd Embodiment of this invention. It is a figure showing DI ratio map at the time of cold memorized by engine ECU which is a control device concerning a 3rd embodiment of the present invention.

Explanation of symbols

10 engine, 20 intake manifold, 30 surge tank, 40 intake duct, 42 air flow meter, 50 air cleaner, 60 electric motor, 70 throttle valve, 80 exhaust manifold, 90 three-way catalytic converter, 100 accelerator pedal, 110 in-cylinder injector , 112 cylinder, 120 Injector injector, 130 Fuel distribution pipe, 140 Check valve, 150 High pressure fuel pump, 152 Electromagnetic spill valve, 160 Fuel distribution pipe (low pressure side), 170 Fuel pressure regulator, 180 Low pressure fuel pump, 190 fuel filter, 200 fuel tank, 300 engine ECU, 310 bidirectional bus, 320 ROM, 330 RAM, 340 CPU, 350 input port, 360 output port, 370, 390, 410, 430, 50 A / D converter, 380 a water temperature sensor, 400 a fuel pressure sensor, 420 an air-fuel ratio sensor, 440
Accelerator opening sensor, 460 rpm sensor.

Claims (5)

A control device for an internal combustion engine comprising a first fuel injection means for injecting fuel into a cylinder and a second fuel injection means for injecting fuel into an intake passage,
In the first injection region, fuel is injected only from the first fuel injection means, and in the second injection region, fuel is injected from the first fuel injection means and the second fuel injection means. Control means for controlling the fuel injection means;
Means for calculating a correction value of the fuel injection amount in each injection region;
Means for calculating a correction value of the fuel injection amount of the first fuel injection means based on a correction value of the fuel injection amount in the first injection region;
Based on the correction value of the fuel injection amount in the second injection region and the correction value of the fuel injection amount of the first fuel injection means, the second fuel injection at different injection ratios in the second injection region. Means for calculating a correction value of the fuel injection amount of the means;
Means for calculating an error in the correction value of the fuel injection amount of the second fuel injection means based on the correction value of the fuel injection amount of the second fuel injection means at the different injection ratios;
A control unit for an internal combustion engine, comprising: means for correcting a correction value of a fuel injection amount of the second fuel injection means based on the calculated error.   2. The control device according to claim 1, further comprising a determination unit configured to determine an abnormality of the second fuel injection unit by comparing the corrected correction value with a predetermined value. Control device for internal combustion engine.   3. The determination unit according to claim 2, wherein the determination unit includes a unit for determining that the second fuel injection unit is in a lean abnormality when the corrected correction value is larger than the predetermined value. Control device for internal combustion engine.   3. The determination unit according to claim 2, wherein the determination unit includes a unit for determining that the second fuel injection unit is rich abnormal when the corrected correction value is smaller than the predetermined value. Control device for internal combustion engine. The first fuel injection means is an in-cylinder injector,
The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the second fuel injection means is an intake passage injector.

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