JP4342379B2 - Fuel injection control device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel injection control device for an internal combustion engine that includes a plurality of fuel injection valves per cylinder and that switches fuel injection valves related to injection according to engine operating conditions. The present invention relates to a fuel injection control device for an internal combustion engine that compensates for a deviation when a deviation occurs between an actual injection amount and a required injection amount.

  In a general internal combustion engine in which one electromagnetic fuel injection valve is provided per cylinder, fuel is pumped from a fuel pump to the fuel injection valve. On the other hand, a required injection amount corresponding to the engine operating state is calculated, and the fuel injection valve is energized for a time corresponding to the required injection amount. This energization opens the fuel injection valve, and the fuel is injected and supplied to the internal combustion engine. This fuel is mixed with the air sucked into the combustion chamber through the intake passage and becomes an air-fuel mixture.

  In the internal combustion engine, when a deposit adheres to the vicinity of the injection port of the fuel injection valve, the actual injection amount may be smaller than the required injection amount. Thus, various techniques for solving such problems have been proposed.

  However, when these techniques are applied to an internal combustion engine in which a plurality of fuel injection valves are provided per cylinder and the control of each fuel injection valve is performed individually, the degree of decrease in the injection amount differs for each fuel injection valve. If the following problem occurs: When fuel is injected from a plurality of fuel injection valves in the same combustion cycle, the ratio of the injection amount of each fuel injection valve to the total injection amount deviates from the target ratio, and the injection The accuracy of the control is reduced. This is because the injection amount is corrected based on one of the fuel injection valves.

  On the other hand, for example, in Patent Document 1, in an internal combustion engine having one fuel injection valve per cylinder, the injection amount of each fuel injection valve is increased or decreased, and each fuel injection is performed based on the change amount of the air-fuel ratio during the increase / decrease period. A technique is described in which a flow rate difference between fuel injection valves is obtained by detecting a flow rate ratio of a valve, and an injection amount is corrected so as to eliminate this flow rate difference.

Therefore, it is conceivable to solve the above problem by applying the technique described in Patent Document 1 to the fuel injection control of the internal combustion engine in which a plurality of fuel injection valves are provided per cylinder described above.
Japanese Patent Laid-Open No. 6-264895

  In the technique of the above combination, even if the degree of decrease in the fuel injection amount differs for each fuel injection valve, the injection amount can be corrected in consideration of the difference. However, for this correction, there arises a new problem that a special engine operating state such as increasing or decreasing the injection amount for each fuel injection valve must be intentionally created separately from the general engine operating state. .

  The present invention has been made in view of such a situation, and an object thereof is an internal combustion engine capable of correcting an injection amount even under a general engine operation state without creating a special operation state. An object of the present invention is to provide an engine fuel injection control device.

In the first aspect of the present invention, the fuel injection valve corresponding to the injection valve operating region provided with a plurality of fuel injection valves per cylinder and switched according to the engine operating state is a fuel injection valve related to injection. And a correction value calculating means for calculating a correction value for compensating for a deviation between the required injection amount and the actual injection amount according to the engine operating state. In the internal combustion engine fuel injection control apparatus, the correction value calculation means is one of all the single injection valve operating regions in which fuel is injected by a single fuel injection valve. Each time the injection valve operation region is switched to the single injection valve operation region according to the engine operating state, an individual correction value for the fuel injection valve in the single injection valve operation region is set. And the injection valve operating area is The overall correction value for the fuel injection valve is calculated on the condition that all the fuel injection valves are operated to switch to the entire injection valve operating region, and the remaining correction values are calculated based on these individual correction values and the overall correction values. It is assumed that individual correction values for the fuel injection valves are calculated.
According to said structure, the injection valve operation area | region according to an engine operation state is calculated, and the fuel injection valve corresponding to the injection valve operation area | region is controlled based on the request | requirement injection amount according to an engine operation state. . By this control, fuel is injected from the fuel injection valve. Here, if a deviation occurs between the required injection amount and the actual injection amount due to a change over time or the like, a correction value for compensating for the deviation is calculated by the correction value calculation means. The calculated correction value is reflected in the fuel injection control, so that an amount of fuel closer to the required injection amount is injected.

  According to the above configuration, when the correction value is calculated by the correction value calculation means, every time the injection valve operation region is switched to the single injection valve operation region according to the engine operating state, the single injection valve operation region An individual correction value for the fuel injector is calculated. This calculation is performed for all the single injection valve operating regions except for one. On the other hand, when the injection valve operation region is switched to the full injection valve operation region in accordance with the engine operating state, the entire correction value is calculated for all the fuel injection valves. Based on these individual correction values and the overall correction value, a correction value for the remaining one fuel injection valve is calculated. In this way, each time the engine operating state changes and the injection valve operating region is switched, individual correction values for each fuel injection valve in the switched injection valve operating region, or all the fuel injection valves The overall correction value of is calculated. Then, the correction value for the remaining one fuel injection valve is obtained based on the individual correction value, the overall correction value, and the like. These correction values are reflected in the fuel injection control, so that the injection amount can be corrected under the general operation state of the internal combustion engine without creating a special engine operation state. Become.

In the invention according to claim 2 , the fuel injection valve corresponding to the injection valve operating region provided with a plurality of fuel injection valves per cylinder and switched according to the engine operating state is a fuel injection valve related to injection. And a correction value calculating means for calculating a correction value for compensating for a deviation between the required injection amount and the actual injection amount according to the engine operating state. The fuel injection control device for an internal combustion engine is reflected in the injection control of the internal combustion engine, wherein the correction value calculation means is a total injection valve operation region in which the injection valve operation region injects fuel from all the fuel injection valves. When switching to, the overall correction value for all the fuel injectors is calculated, and this calculation is performed at least as many times as the number of fuel injectors under different engine operating conditions in the operating region of all the injectors. The total correction made and obtained It is assumed that an individual correction value for each fuel injection valve is calculated based on the value and the individual and overall required injection amounts for the fuel injection valve.

  According to the above configuration, when the correction value is calculated by the correction value calculation means, when the injection valve operating region is switched to the full injection valve operating region in accordance with the engine operating state, the entire correction value for all the fuel injection valves is obtained. Is calculated. This calculation is performed based on the total required injection amount required for all the fuel injection valves and the amount of fuel actually injected from these fuel injection valves (actual injection amount). Therefore, the actual injection amount can be expressed using these overall correction values and the overall required injection amount.

  On the other hand, the overall actual injection amount is the same as the sum of the actual injection amounts of the individual fuel injection valves. The individual actual injection amount can be expressed using an individual correction value for each fuel injection valve and an individual required injection amount for the fuel injection valve in accordance with the same concept as described above. Here, the individual required injection amount is separately calculated for control of the fuel injection valve. For this reason, the individual required injection amount is known at the stage of calculating the overall correction value. On the other hand, the individual correction value is unknown at the stage of calculating the entire correction value.

  Therefore, in the relationship that the total actual injection amount is equal to the sum of the individual actual injection amounts for each fuel injection valve, the same number of individual correction values as the number of fuel injection valves are unknown. In order to clarify these unknown individual correction values, the above-mentioned relationship is required as many as the number of fuel injectors.

In this regard, in the invention described in claim 2 , the calculation of the entire correction value is performed at least as many times as the number of fuel injectors under different engine operating states in the entire injector operating region. As a result of this calculation, the above-described relationship is obtained in the same number as the number of fuel injection valves. Therefore, it is possible to calculate a correction value for each individual fuel injection valve based on the plurality of obtained relationships, that is, based on the overall correction value and the individual and overall required injection amounts for the fuel injection valve. Become. These correction values are reflected in the fuel injection control, so that the injection amount can be corrected under the general operation state of the internal combustion engine without creating a special engine operation state. Become.

According to a third aspect of the present invention, in the first or second aspect of the present invention, an air / fuel ratio detecting means for detecting an air / fuel ratio of an air / fuel mixture based on a concentration of oxygen in exhaust gas, and an intake air for detecting an intake air amount And a correction value calculation means for calculating the correction value based on the actual injection amount calculated based on the air-fuel ratio by the air-fuel ratio detection means and the intake air amount by the intake air amount detection means. Suppose you use it.

  According to the above configuration, in the cylinder, a mixture of the fuel injected from the fuel injection valve and the air sucked through the intake passage is generated. The air-fuel mixture is combusted, and the gas (exhaust gas) generated by the combustion is discharged from the cylinder to the exhaust passage. Based on the oxygen concentration in the exhaust gas, an air-fuel ratio that is a weight ratio of air to fuel in the air-fuel mixture is detected by the air-fuel ratio detection means. On the other hand, the amount of air taken into the cylinder (intake air amount) is detected by the intake air amount detection means. Based on the air-fuel ratio and intake air amount thus detected, the actual amount of fuel injected from the fuel injection valve (actual injection amount) is calculated. The calculated actual injection amount is used for calculation of the correction value by the correction value calculation means.

The invention according to claim 4, in the invention described in any one of claims 1-3, wherein the correction value calculating means, the ratio between the required injection amount and the actual injection amount and the correction value Suppose it is a thing.

  Here, the ratio between the actual injection amount and the required injection amount indicates how much fuel is actually injected with respect to the required injection amount. It can be said that it represents the deviation of quantity indirectly. Therefore, by using such a ratio as a correction value and reflecting it in the fuel injection control, it becomes possible to inject an amount of fuel closer to the required injection amount.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the correction value calculating means is a required injection for a fuel injection valve in an injection valve operating region in accordance with an engine operating state. The amount is compared with the actual injection amount, and the correction value is calculated on the condition that the actual injection amount changes by a predetermined reference value or more with respect to the required injection amount.

  According to the above configuration, when the fuel injection valve related to fuel injection is controlled in the injection valve operating region corresponding to the engine operating state, the correction value calculation means determines the required injection amount for the fuel injection valve and the actual injection amount. Is compared with the amount of fuel injected into the engine (actual injection amount). Based on this comparison result, whether or not the correction value can be calculated is determined. That is, when the actual injection amount has not changed by a predetermined value or more with respect to the required injection amount (when the deviation amount of the actual injection amount with respect to the required injection amount is small), the correction value is not calculated. On the other hand, when the actual injection amount changes by a predetermined value or more with respect to the required injection amount (when the deviation amount is large), the correction value is calculated. As a result, the correction value is calculated only when the correction value needs to be reflected in the fuel injection control.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, a vehicle is equipped with a gasoline engine (hereinafter simply referred to as an engine) 11 as an internal combustion engine. The engine 11 includes a cylinder block 13 having a plurality of cylinders (cylinders) 12. A piston 14 is accommodated in each cylinder 12 so as to be able to reciprocate. Each piston 14 is connected via a connecting rod 15 to a crankshaft 16 that is an output shaft of the engine 11. The reciprocating motion of each piston 14 is converted to rotational motion by the connecting rod 15 and then transmitted to the crankshaft 16.

  An intake passage 22 having a throttle valve 18, a surge tank 19, an intake manifold 21, and the like is connected to the combustion chamber 17 for each cylinder 12, and air outside the engine 11 passes through the above portions of the intake passage 22 in order. And taken into the combustion chamber 17. The throttle valve 18 is rotatably provided upstream of the surge tank 19 in the intake passage 22 and is driven by an actuator 23 such as a step motor. The actuator 23 operates in response to a depression operation of the accelerator pedal 24 by the driver, and rotates the throttle valve 18. The intake air amount that is the amount of air that flows through the intake passage 22 varies according to the throttle opening degree TA that is the rotation angle of the throttle valve 18.

  The combustion chamber 17 is connected to an exhaust passage 27 having an exhaust manifold 25, a catalytic converter 26, and the like. Combustion gas generated in the combustion chamber 17 passes through the above portions of the exhaust passage 27 in order and It is discharged outside.

  The engine 11 is provided with an intake valve 28 that opens and closes between the intake passage 22 and the combustion chamber 17 and an exhaust valve 29 that opens and closes between the exhaust passage 27 and the combustion chamber 17 so as to reciprocate. The intake valve 28 is driven by an intake camshaft 31 that rotates in conjunction with the crankshaft 16. The exhaust valve 29 is driven by an exhaust camshaft 32 that rotates in conjunction with the crankshaft 16.

  The engine 11 is provided with a plurality of electromagnetic fuel injection valves INJ (i) that open by energization and inject fuel. As these fuel injection valves INJ (i), a plurality of the same type may be used, or a single type or a plurality of different types may be used. In addition, (i) is for distinguishing the some fuel injection valve INJ, and takes the value of 1-n (n is a natural number of 2 or more).

  FIG. 1 shows a mode in which two types of fuel injection valves INJ (1) and INJ (2) are provided one by one. One fuel injection valve INJ (1) is for injecting fuel (port injection) toward the intake port 33 which is a connection portion of the intake passage 22 with the combustion chamber 17, and the other fuel injection valve INJ. (2) is for directly injecting fuel into the combustion chamber 17 (in-cylinder injection).

  The amount (injection amount) of fuel injected and supplied from each fuel injection valve INJ (i) is basically determined by the energization time of each fuel injection valve INJ (i), that is, the valve opening time. The fuel injected from these fuel injection valves INJ (i) and the air flowing through the intake passage 22 are mixed to form an air-fuel mixture.

  The fuel injection valve INJ (i) related to the injection is switched according to the operating state of the engine 11. For this switching, an area determination map is used in which the operating area of the engine 11 represented by the engine speed NE and the engine load is divided into a plurality of injection valve operating areas. These injection valve operation areas include an operation area (single injection valve operation area) in which fuel is injected by a single fuel injection valve INJ (i) for each cylinder 12 and all fuel injection valves for each cylinder 12. An operation region (all injection valve operation region) for injecting fuel at INJ (i) is included.

For example, when two types of fuel injection valves INJ (1) and INJ (2) are provided for each cylinder as described above, in the region determination map, the operation of the engine 11 is performed. The region is divided into the following three injection valve operating regions.
A single injection valve operating region in which the fuel injection valve INJ (2) for in-cylinder injection is stopped and only the fuel injection valve INJ (1) for port injection is operated.
A single injection valve operation region in which the fuel injection valve INJ (1) for port injection is stopped and only the fuel injection valve INJ (2) for in-cylinder injection is operated.
A full injection valve operating region in which both the port injection and in-cylinder fuel injection valves INJ (1) and INJ (2) are operated.

  Then, the injection valve operating region to which the engine rotational speed NE and the engine load at that time belong is determined, and the fuel injection valve INJ (i) corresponding to the injection valve operating region is set as the fuel injection valve related to the injection. .

  A spark plug 34 is attached to the engine 11 corresponding to each cylinder 12. The spark plug 34 is driven based on the ignition signal from the igniter 35. A high voltage output from the ignition coil 36 is applied to the spark plug 34. The air-fuel mixture is ignited by the spark discharge of the spark plug 34 and explodes and burns. The piston 14 is reciprocated by the high-temperature and high-pressure combustion gas generated at this time, the crankshaft 16 is rotated, and the driving force (output torque) of the engine 11 is obtained. The gas (exhaust gas) generated by the combustion is discharged to the exhaust passage 27 when the exhaust valve 29 is opened.

  The vehicle is provided with various sensors for detecting the state of each part of the vehicle including the operating state of the engine 11. For example, a crank angle sensor 41 that generates a pulse signal every time the crankshaft 16 rotates by a certain angle is provided in the vicinity of the crankshaft 16. The signal of the crank angle sensor 41 is used for calculation of a crank angle that is the rotation angle of the crankshaft 16 and an engine rotation speed NE that is the rotation speed of the crankshaft 16 per unit time.

  A throttle sensor 42 that detects the throttle opening degree TA is provided in the vicinity of the throttle valve 18. An intake air amount sensor 43 such as an air flow meter is provided upstream of the throttle valve 18 in the intake passage 22 as intake air amount detection means for detecting the amount of intake air. In the middle of the exhaust passage 27, an air-fuel ratio sensor 44 such as an oxygen sensor is provided as air-fuel ratio detection means for detecting the air-fuel ratio of the air-fuel mixture from the concentration of oxygen in the exhaust gas. An accelerator sensor 45 that detects the amount of depression of the accelerator pedal 24 (accelerator depression amount) by the driver is provided in the passenger compartment.

  In order to control each part of the engine 11 based on the detection values of the various sensors 41 to 45 and the like described above, an electronic control unit 51 configured mainly with a microcomputer is provided. In the electronic control unit 51, a central processing unit (CPU) performs arithmetic processing according to a control program and initial data stored in a read-only memory (ROM), and executes various controls based on the calculation results. The calculation result by the CPU is temporarily stored in a random access memory (RAM). Further, the electronic control device 51 includes a backup RAM that stores and holds various data even after the power supply to the device is stopped.

  Examples of the control performed by the electronic control unit 51 include ignition timing control and fuel injection control. Here, in the ignition timing control, the state of the engine 11 is detected based on signals from various sensors, and the optimal ignition timing is calculated for the state of the engine 11 at that time. When the crank angle calculated based on the signal from the crank angle sensor 41 reaches the ignition timing, an ignition signal is output to the igniter 35. The igniter 35 interrupts the primary current of the ignition coil 36 based on the ignition signal. Due to this interruption, a high voltage is generated in the secondary coil of the ignition coil 36 and the ignition plug 34 is ignited. The air-fuel mixture is ignited and burned by spark discharge accompanying ignition of the spark plug 34.

  In the fuel injection control, the amount of fuel (required injection amount) required for the operation of the engine 11 is calculated from the signals of various sensors that detect the state of the engine 11, and the fuel injection valve INJ (i ) Is controlled.

  In this fuel injection control, first, an injection valve operation region to which the operating state of the engine 11 at that time belongs is determined, and the fuel injection valve INJ (i) corresponding to the injection valve operation region is a fuel injection valve related to injection. It is said. Further, the individual required injection amount required for each fuel injection valve INJ (i) to generate an air-fuel mixture with a predetermined air-fuel ratio (for example, the theoretical air-fuel ratio) is determined by the engine rotational speed NE, the throttle sensor by the crank angle sensor 41. 42 is calculated based on the throttle opening by 42, the intake air amount by the intake air amount sensor 43, and the like. The calculation of the individual required injection amount is performed for all the fuel injection valves INJ (i) related to the injection. Here, the injection amount required for each fuel injection valve INJ (i) is referred to as an individual required injection amount Q (i), and the total required for the fuel injection valve INJ (i) related to injection in each injection valve operating region. Is the total required injection amount Qth. Note that “i” in parentheses is for distinguishing individual required injection amounts, and corresponds to “i” in the fuel injection valve INJ (i). In the single injection valve operating region, as shown by the following equation (1), the individual required injection amount Q (i) for the single fuel injection valve INJ (i) becomes the total required injection amount Qth.

Qth = Q (i) (1)
Further, in the entire injection valve operating region, as shown by the following equation (2), the total of the individual required injection amounts Q (i) for the respective fuel injection valves INJ (i) becomes the total required injection amount Qth.

Qth = ΣQ (i) (2)
However, ΣQ (i) = Q (1) + Q (2) +... + Q (n).
Therefore, in the engine 11 in which two fuel injection valves INJ (1) and (2) are used per cylinder, the total required injection amount Qth is expressed by the following equation (3).

Qth = Q (1) + Q (2) (3)
Then, the corresponding fuel injection valve INJ (i) is energized for a time corresponding to the individual required injection amount Q (i). With this energization, the fuel injection valve INJ (i) is opened and fuel is injected. The actual amount of fuel injected in this way (actual injection amount Qreal) should be equal to or close to the total required injection amount Qth as shown in the following equation (4).

Qreal = Qth (4)
However, the actual injection amount Qreal may be smaller than the total required injection amount Qth due to changes over time such as deposits adhering to the vicinity of the injection port of the fuel injection valve INJ (i).

  Accordingly, a correction value for compensating for the difference between the total required injection amount Qth and the actual injection amount Qreal is calculated, and this correction value is reflected in the fuel injection control. For example, the energization time for the fuel injection valve INJ (i) is increased or the energization start timing is advanced.

  This correction value includes the individual correction value K (i) for each fuel injection valve INJ (i) related to the injection for each single injection valve operation region, and also includes the injection for each injection valve operation region at that time. An overall correction value Kave for the entire associated fuel injection valve INJ (i) is included.

Here, there is a relationship expressed by the following equation (5) among the actual injection amount Qreal, the total correction value Kave, and the total required injection amount Qth.
Qreal = Kave * Qth (5)
When this equation (5) is modified, the following equation (6) representing the overall correction value Kave is obtained in the relationship between the actual injection amount Qreal and the total required injection amount Qth.

Kave = Qreal / Qth (6)
In the single injection valve operation region, there is a relationship expressed by the following equation (7) among the actual injection amount Qreal, the individual correction value K (i), and the individual required injection amount Q (i).

Qreal = K (i) * Q (i) (7)
When this equation (7) is modified, the following equation (8) representing the individual correction value K (i) is obtained in the relationship between the actual injection amount Qreal and the individual required injection amount Q (i).

K (i) = Qreal / Q (i) (8)
Further, in the entire injection valve operating region, the relationship expressed by the following equation (9) among the overall correction value Kave, the total required injection amount Qth, the individual correction value K (i), and the individual required injection amount Q (i). There is.

Kave * Qth = Σ (K (i) * Q (i)) (9)
However, Σ (K (i) * Q (i)) = K (1) * Q (1) + K (2) * Q (2) +... + K (n) * Q (n).

Therefore, in the engine 11 in which two fuel injection valves INJ (1) and (2) are used per cylinder, the above equation (9) is expressed by the following equation (10).
Kave * Qth = K (1) * Q (1) + K (2) * Q (2) (10)
In the single injection valve operating region, the individual required injection amount Q (i) for the fuel injection valves INJ (i) other than one is “0”. Therefore, the above formula (9) is expressed by the following formula (11).

Kave * Qth = K (i) * Q (i) (11)
In the single injection valve operating region, the relationship of Qth = Q (i) is established. From this and the above equation (11), the following equation (12) is established. That is, the individual correction value K (i) for one fuel injection valve INJ (i) becomes the overall correction value Kave.

K (i) = Kave (12)
The flowchart in FIG. 2 shows a series of processes performed when the individual correction value K (i) is calculated. These processes are started by the electronic control unit 51 when the engine 11 is started. Here, it is assumed that the engine 11 uses n fuel injection valves INJ (i).

  First, in step 110, the electronic control unit 51 reads the total required injection amount Qth required for the fuel injection valve INJ (i). This total required injection amount Qth is calculated at any time in another calculation routine based on the operating state of the engine 11 such as the engine rotational speed NE, the throttle opening degree, and the intake air amount.

  Subsequently, in step 120, it is determined whether or not the flow rate reduction rate k is larger than a preset reference value α (> 1). The flow rate reduction rate k is a parameter that represents how much the actual injection amount Qreal is reduced with respect to the total required injection amount Qth described above. Note that the flow rate decrease rate k is “1” when the engine 11 is started, due to the processing of step 190 (which will be described later) during the execution of the previous correction value calculation routine. Therefore, immediately after the engine is started, the determination condition of step 120 is not satisfied.

  In this case (k ≦ α), it is considered unnecessary to calculate the individual correction value K (i). Therefore, in steps 130 and 140, processing for calculating and updating the flow rate decrease rate k is performed. In step 130, the actual injection amount Qreal is calculated based on the operating state of the engine 11, for example, the air-fuel ratio by the air-fuel ratio sensor 44, the intake air amount by the intake air amount sensor 43, and the like. Next, at step 140, the total required injection amount Qth at step 110 is divided by the actual injection amount Qreal at step 130, and the result is taken as the flow rate reduction rate k. After step 140, the process returns to step 120.

  On the other hand, if the determination condition of step 120 is satisfied (k> α), it is considered that the individual correction value K (i) needs to be calculated, so the processing of steps 150 and 155 is performed. In step 150, the region determination map is referenced to determine the injection valve operation region to which the engine speed NE and the engine load at that time belong, and whether or not the injection valve operation region is a single injection valve operation region. judge. In step 155, it is determined whether the individual correction value K (i) has not yet been calculated for the fuel injection valve INJ (i) corresponding to the single injection valve operating region. Only when the determination conditions of these steps 150 and 155 are both satisfied, the process proceeds to the next step 160. When at least one of steps 150 and 155 is not satisfied, for example, when it is the entire injection valve operation region (step 150: NO), or it is a single injection valve operation region, the individual required injection amount Q (i) is already If so, the process returns to step 150.

  In step 160 which has shifted from step 155, the individual required injection amount Q (i) for the fuel injection valve INJ (i) is read. This total required injection amount Qth is calculated at any time in another calculation routine based on the operating state of the engine 11 such as the engine rotational speed NE, the throttle opening degree, and the intake air amount.

Next, in step 165, as in step 130 described above, the actual injection amount Qreal is calculated based on the engine operating state, for example, the air-fuel ratio, the intake air amount, and the like.
In step 170, the individual correction value K (i) is calculated by dividing the actual injection amount Qreal in step 165 by the individual required injection amount Q (i) in step 160.

  In step 175, it is determined whether the individual correction value K (i) has been calculated for all the fuel injection valves INJ (i). If this determination condition is not satisfied, the process returns to step 150, and if satisfied, in step 190, the flow rate decrease rate k is returned to the initial value (= 1) in preparation for the next processing. After the processing of step 190, this correction value calculation routine is terminated.

  On the other hand, in the engine 11 in which two fuel injection valves INJ (1) and INJ (2) are used per cylinder, the individual correction values K (1) and K (2) are, for example, the procedure shown in FIG. Is calculated according to

  Each process of this calculation is performed based on flags F1 and F2. The flag F1 indicates the calculation history of the individual correction value K (1) for the fuel injection valve INJ (1). Similarly, the flag F2 indicates the calculation history of the individual correction value K (2) for the fuel injection valve INJ (2). The initial value (value at the time of engine start) of both flags F1 and F2 is “0”, and is switched to “1” with the calculation of the individual correction values K (1) and K (2).

  The electronic control unit 51 sequentially performs the processing of steps 110 to 140 in FIG. 2 described above, and then in step 200, refers to the area determination map, and belongs to the engine rotational speed NE and the engine load at that time. The injection valve operating area is determined, and it is determined whether or not the injection valve operating area is a single injection valve operating area. If this determination condition is not satisfied, the process of step 200 is repeated. If the determination condition is satisfied, in step 205, the injection valve operating region in step 200 is subject to one fuel injection valve INJ (1) to be operated. It is determined whether or not it is a single injection valve operation region (described as INJ (1) operation region in FIG. 3).

  If the determination condition in step 205 is satisfied, it is determined in step 210 whether the flag F1 is “1”. If this determination condition is satisfied (F1 = 1), the individual correction value K (1) has already been calculated. On the other hand, if the determination condition of step 210 is not satisfied (F1 = 0), the individual correction value K (1) has not been calculated yet, so in step 215, a request is made to the fuel injection valve INJ (1). The individual required injection amount Q (1) being read is read. In step 220, the actual injection amount Qreal is calculated based on the air-fuel ratio, the intake air amount, and the like. In step 225, the individual correction value K (1) is calculated by dividing the actual injection amount Qreal in step 220 by the individual required injection amount Q (1) in step 215 according to the above equation (8). In step 230, the flag F1 is switched from “0” to “1”, and the process proceeds to step 235.

  For the fuel injection valve INJ (2), the same processing as that for the fuel injection valve INJ (1) is performed. If the determination condition of step 205 is not satisfied, that is, if the fuel injection valve INJ (2) is in the single injection valve operating region, the flag F2 is “1” in step 240. Determine if. If this determination condition is satisfied (F2 = 1), the individual correction value K (2) has already been calculated. On the other hand, if the determination condition of step 240 is not satisfied (F2 = 0), the individual correction value K (2) has not been calculated yet, so in step 245, a request is made to the fuel injection valve INJ (2). The individual required injection amount Q (2) being read is read. In step 250, the actual injection amount Qreal is calculated based on the air-fuel ratio, the intake air amount, and the like. In step 255, the individual correction value K (2) is calculated by dividing the actual injection amount Qreal in step 250 by the individual required injection amount Q (2) in step 245 according to the above equation (8). In step 260, the flag F2 is switched from “0” to “1”, and the process proceeds to step 235.

  In step 235, it is determined whether the individual correction value K (1) for the fuel injection valve INJ (1) and the individual correction value K (2) for the fuel injection valve INJ (2) are both calculated. For this determination, for example, the flags F1 and F2 described above can be used. When F1 = 1 and F2 = 1, both individual correction values K (1) and K (2) are calculated. If the determination condition in step 235 is not satisfied, the process returns to step 200. If the determination condition is satisfied, in step 275, the flow rate decrease rate k is returned to “1” in preparation for the next processing, and both the flags F1 and F2 are set. Switch from “1” to “0”. After the processing of step 275, the correction value calculation routine is terminated.

  According to the correction value calculation routine of FIG. 2 and FIG. 3 described above, the individual correction value K (1) is calculated every time the injection valve operation region is switched to the single injection valve operation region in accordance with the operating state of the engine 11. The That is, when the operating state of the engine 11 changes and the injection valve operating region is switched to the predetermined single injection valve operating region, the individual correction value for the fuel injection valve INJ (i) in the single injection valve operating region. K (i) is calculated. Further, when the operating state of the engine 11 changes and the injection valve operating region is switched to another single injection valve operating region, the individual correction value for the fuel injection valve INJ (i) in that single injection valve operating region. K (i) is calculated. Thus, each time the operating state of the engine 11 changes and the injection valve operating region is switched to the single injection valve operating region, and the single fuel injection valve INJ (i) related to injection is switched, individual correction is performed. A value K (i) is calculated.

  In the calculation, the individual correction value K (i) is calculated according to the equation (8) based on the individual required injection amount Q (i) and the actual injection amount Qreal in the corresponding single injection valve operating region. .

  These individual correction values K (i) are reflected in fuel injection control (for example, energization time and energization timing for the fuel injection valve INJ (i)). Therefore, even if the deposit is attached in the vicinity of the injection port of the fuel injection valve INJ (i) and the actual injection amount Qreal is smaller than the required injection amounts Qth, Q (i), the individual correction value K (i) As a result, the actual injection amount Qreal is brought closer to the required injection amounts Qth and Q (i).

According to the first embodiment described in detail above, the following effects can be obtained.
(1) Each time the operating state of the engine 11 changes and the injection valve operation region is switched to the single injection valve operation region, and the single fuel injection valve INJ (i) related to injection is switched, the individual correction value K (i) is calculated and reflected in the fuel injection control. For this reason, the injection amount can be corrected by utilizing the change in the operation state under the general operation state of the engine 11 such as the engine load and the engine speed NE without creating a special operation state. Can be done.

  (2) Each time the injection valve operation region is switched to the single injection valve operation region, the individual correction value for the fuel injection valve INJ (i) is based on the individual required injection amount Q (i) and the actual injection amount Qreal. K (i) is calculated. Therefore, the individual correction value K (i) for each fuel injection valve INJ (i) in (1) can be reliably calculated every time the operation is switched to the single injection valve operating region.

  (3) Based on the air-fuel ratio of the air-fuel mixture detected by the air-fuel ratio sensor 44, the intake air amount detected by the intake air amount sensor 43, etc., the actual injection amount Qreal used for calculating the individual correction value K (i) Can be calculated reliably.

  (4) The ratio (Qreal / Q (i)) between the actual injection amount Qreal and the individual required injection amount Q (i) is the actual injection amount of fuel with respect to the required injection amount. It can be said that the deviation of the actual injection amount Qreal with respect to the individual required injection amount Q (i) is indirectly represented. Therefore, by using such a ratio as the individual correction value K (i) and reflecting the fuel injection control, it becomes possible to inject an amount of fuel closer to the total required injection amount Qth.

  (5) The flow rate reduction rate k is obtained, and the individual correction value K (i) is calculated only when this is larger than the reference value α. In other words, the total required injection amount Qth and the actual injection amount Qreal are compared, and whether or not the individual correction value K (i) can be calculated is determined based on the comparison result. Specifically, the individual correction value K (i) is not calculated when the actual injection amount Qreal has not changed by a predetermined value or more with respect to the total required injection amount Qth (k ≦ α). On the other hand, when the actual injection amount Qreal changes by a predetermined value or more with respect to the total required injection amount Qth (k> α), the individual correction value K (i) is calculated. In this way, it is possible to calculate the individual correction value K (i) only when necessary, and to reduce unnecessary calculation opportunities.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, all the individual correction values K (i) are calculated once immediately after the engine 11 is started, and thereafter, the flow rate reduction rate k becomes larger than the reference value α during the operation of the engine 11. In this case, it is greatly different from the first embodiment in that the individual correction value K (i) is calculated. Accordingly, the same processes as those in the first embodiment are denoted by the same number of steps and the description thereof is omitted.

  The flowcharts of FIGS. 4 and 5 show a series of processes performed in calculating the individual correction value K (i) in the engine 11 in which n fuel injection valves INJ (i) are used per cylinder. These processes are started by the electronic control unit 51 when the engine 11 is started.

  When the engine 11 is started, the electronic control unit 51 first determines in step 100 of FIG. 4 whether or not the number of times t the individual correction value K (i) is calculated is “0”. It should be noted that the calculation count t is “0” when the engine 11 is started due to the processing of step 190 (which will be described later) during the execution of the previous correction value calculation routine. Therefore, immediately after the engine 11 is started, the determination condition of step 100 is satisfied.

  In this case (t = 0), the processing in steps 150 to 175 in FIG. 5 is performed, and individual correction values K (i) are calculated for all the fuel injection valves INJ (i). Each processing in steps 150 to 175 is the same as that described in the first embodiment.

  If the determination condition in step 175 is satisfied, the calculation count t is updated in step 180. That is, a predetermined value, “1” is added to the current calculation count t, and the addition result is stored as a new calculation count t. Immediately after the engine 11 is started, the updated calculation count t becomes “1” by the addition processing in step 180 accompanying the calculation of the individual correction value K (i).

  Next, in step 185, it is determined whether or not the calculation count t is a predetermined determination value, for example, “1” or less. The determination condition in step 185 is for determining whether or not to continue calculating the individual correction value K (i). Immediately after the engine 11 is started, the calculation number t is “1” by the process of step 180, so that the determination condition of step 185 is satisfied. In this case, the process returns to step 100 in FIG.

  By the process of step 180, the determination condition of step 100 is not satisfied. In this case, the processing of steps 110 to 140 is performed. The contents of these processes are the same as those described in the first embodiment. Therefore, only when the flow rate reduction rate k is larger than the reference value α, the process proceeds to a series of processes for calculating the individual correction values K (i) for all the fuel injection valves INJ (i).

  Then, after a series of processes for calculating the individual correction value K (i), the process of step 180 is performed. By this processing, the determination condition in the next step 185 is not satisfied. In this case, in step 190, the flow rate reduction rate k and the calculation count t are returned to their initial values (k = 1, t = 0), and then the correction value calculation routine is terminated.

  FIG. 6 shows a procedure for calculating the individual correction values K (1) and K (2) in the engine 11 in which two fuel injection valves INJ (1) and INJ (2) are used per cylinder. Show. This embodiment is different from the first embodiment (see FIGS. 2 and 3) in the following points.

  Prior to the processing of step 110, the processing of step 100 (whether t = 0) is performed. The content of the process in step 100 is the same as the content of the process in step 100 when n fuel injection valves INJ (i) are used per cylinder.

  The processing of steps 265 and 270 is added between the processing of step 235 and the processing of step 275 (see FIG. 4). The contents of the processes in steps 265 and 270 are the same as the contents of the processes in steps 180 and 185 when n fuel injection valves INJ (i) are used per cylinder described above.

According to the second embodiment, in addition to the above (1) to (5), the following effects can be obtained.
(6) Count the number of times t the individual correction value K (i) is calculated, and calculate the individual correction value K (i) based on the calculated number t, or the individual correction value K (i) using the flow rate decrease rate k. Whether to determine whether or not is possible is switched. Therefore, immediately after the engine is started, the individual correction value K (i) can be calculated for all the fuel injection valves INJ (i) regardless of the flow rate reduction rate k, and this can be reflected in the fuel injection control. Thereafter, the individual correction value K (i) can be calculated only when the flow rate reduction rate k increases by comparing the flow rate reduction rate k with the reference value α.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, every time the injection valve operating region is switched, the total correction value Kave is calculated based on the total required injection amount Qth and the actual injection amount Qreal. When the injection valve operation region is a single injection valve operation region, the overall correction value Kave is set to the individual correction value K (i) for the fuel injection valve INJ (i) in the single injection valve operation region. This is different from the first embodiment. This is because K (i) = Kave holds in the single injection valve operating region, as described above using Expression (12).

  The flowchart in FIG. 7 shows a series of processes performed in calculating the individual correction value K (i) in the engine 11 in which n fuel injection valves INJ (i) are used per cylinder. These processes are started when the engine 11 is started, and thereafter repeatedly executed with a predetermined cycle.

  First, in step 300, the electronic control unit 51 reads the total required injection amount Qth required for the fuel injection valve INJ (i) related to the injection at that time. In step 305, the actual injection amount Qreal for the fuel injection valve INJ (i) is calculated based on the operating state of the engine 11 such as the air-fuel ratio and the intake air amount. In step 310, the total correction value Kave is calculated by dividing the actual injection amount Qreal in step 305 by the total required injection amount Qth in step 300 according to the above equation (6).

  Next, in step 315, the region determination map is referred to, and the injection valve operation region to which the engine rotation speed NE and the engine load at that time belong is determined. The injection valve operation region is a single injection valve operation region. Determine whether or not. If this determination condition is not satisfied, the process returns to step 300. If the determination condition is satisfied, in step 320, the entire correction value Kave in step 310 is determined as a single fuel injection related to injection according to the above equation (12). It is set (stored) as an individual correction value K (i) for the valve INJ (i).

  In step 325, it is determined whether the individual correction value K (i) has been calculated for all the fuel injection valves INJ (i). If this determination condition is not satisfied, the process returns to step 300. If the determination condition is satisfied, the correction value calculation routine is terminated.

  On the other hand, in the engine 11 in which two fuel injection valves INJ (1) and INJ (2) are used per cylinder, the individual correction values K (1) and K (2) are, for example, the procedure shown in FIG. Is calculated according to

  Each process of this calculation is performed based on flags F1 and F2. Both flags F1 and F2 indicate the calculation history of the individual correction values K (1) and K (2), similar to those described in the first embodiment. The initial value (value at the time of engine start) of both flags F1 and F2 is “0”, and is switched to “1” with the calculation of the individual correction values K (1) and K (2).

  First, in steps 400 to 415, the electronic control unit 51 performs the same processing as in steps 300 to 315. That is, in step 400, the total required injection amount Qth required for the fuel injection valve INJ (i) related to the injection at that time is read. In step 405, the actual injection amount Qreal for the fuel injection valve INJ (i) is calculated based on the operating state of the engine 11 such as the air-fuel ratio and the intake air amount. In step 410, the total correction value Kave is calculated by dividing the actual injection amount Qreal in step 405 by the total required injection amount Qth in step 400 according to the above-described equation (6). In step 415, the region determination map is referenced to determine the injection valve operation region to which the engine speed NE and the engine load at that time belong, and whether or not the injection valve operation region is a single injection valve operation region. Determine. If this determination condition is not satisfied, the process returns to step 400. If the determination condition is satisfied, the process proceeds to step 420.

  In step 420, the single injection valve operation region in step 415 is the single injection valve operation region in which one fuel injection valve INJ (1) is the target of operation (in FIG. 8, the INJ (1) operation region). Whether or not). If the determination condition of step 420 is satisfied, it is determined in step 425 whether the flag F1 is “1”. If this determination condition is satisfied (F1 = 1), the individual correction value K (1) has already been calculated. On the other hand, if the determination condition in step 425 is not satisfied (F1 = 0), the individual correction value K (1) has not yet been calculated. Therefore, in step 430, according to the above equation (12), the above step The overall correction value Kave at 410 is set (stored) as an individual correction value K (1) for the fuel injection valve INJ (1). In step 435, the flag F1 is switched from “0” to “1”, and the process proceeds to step 440.

  The fuel injection valve INJ (2) is also processed in the same manner as the fuel injection valve INJ (1). If the determination condition in step 420 is not satisfied, that is, if the fuel injection valve INJ (2) is in the single injection valve operation region, the flag F2 is “1” in step 445. Determine if. If this determination condition is satisfied (F2 = 1), the individual correction value K (2) has already been calculated. On the other hand, if the determination condition in step 445 is not satisfied (F2 = 0), the individual correction value K (2) has not yet been calculated. Therefore, in step 450, the above step (12) is performed. The overall correction value Kave at 410 is set (stored) as an individual correction value K (2) for the fuel injection valve INJ (2). In step 455, the flag F2 is switched from “0” to “1”, and the process proceeds to step 440.

  In step 440, it is determined whether the individual correction value K (1) for the fuel injection valve INJ (1) and the individual correction value K (2) for the fuel injection valve INJ (2) are both calculated. For this determination, for example, the flags F1 and F2 described above can be used. When F1 = 1 and F2 = 1, both individual correction values K (1) and K (2) are calculated. If the determination condition of step 440 is not satisfied, the process returns to step 400. If the determination condition is satisfied, in step 460, both the flags F1 and F2 are switched from “1” to “0” in preparation for the next processing. After the processing of step 460, the correction value calculation routine is terminated.

Therefore, according to the third embodiment, in addition to the effects (1), (3), and (4) described above, the following effect (7) according to the above (2) is obtained.
(7) Every time the injection valve operating region is switched according to the operating state of the engine 11, the total correction value Kave is calculated based on the total required injection amount Qth and the actual injection amount Qreal. If the switched injection valve operation region is a single injection valve operation region, the individual correction value K for the fuel injection valve INJ (i) related to injection in the single injection valve operation region is used as the overall correction value Kave. (I). In this way, the individual correction value K (i) for each fuel injection valve INJ (i) can be reliably calculated every time the operation is switched to the single injection valve operating region.

<Fourth embodiment>
Next, a fourth embodiment embodying the present invention will be described with reference to FIGS. In the fourth embodiment, the individual correction value K (i) is calculated every time when the injection valve operation region is switched to the single injection valve operation region for all the single injection valve operation regions except for one. At the same time, the overall correction value Kave is calculated on condition that the injection valve operation region is switched to the full injection valve operation region. The first implementation is that the individual correction values K (i) for the remaining fuel injection valves INJ (i) are calculated based on these individual correction values K (i) and the overall correction values Kave. It is very different from the form. This is because Kave * Qth = Σ (K (i) * Q (i)) holds as described above using Equation (9). That is, if the values of (n−1) are found for the left side and the right side in Equation (9), the remaining one individual correction value K (i) can be obtained by calculation.

  The flowchart of FIG. 9 shows a series of processes performed when calculating the individual correction value K (i) in the engine 11 in which n fuel injection valves INJ (i) are used per cylinder. These processes are started when the engine 11 is started, and thereafter repeatedly executed with a predetermined cycle.

  In step 500, the electronic control unit 51 first reads the total required injection amount Qth required for the fuel injection valve INJ (i) related to the injection at that time. In step 505, the actual injection amount Qreal for the fuel injection valve INJ (i) is calculated based on the operating state of the engine 11 such as the air-fuel ratio and the intake air amount. In step 510, the overall correction value Kave is calculated by dividing the actual injection amount Qreal in step 505 by the total required injection amount Qth in step 500 in accordance with the equation (6) described above.

  Next, in step 515, the region determination map is referenced to determine the injection valve operation region to which the engine speed NE and the engine load at that time belong, and the injection valve operation region is a single injection valve operation region. Determine whether or not. If this determination condition is satisfied, in step 520, the individual correction for the fuel injection valve INJ (i) that is operating singly is made from the overall correction value Kave in step 510 according to the above equation (12). Set (store) as value K (i). After step 520, the process proceeds to step 540.

  On the other hand, if the determination condition of step 515 is not satisfied, it is determined in step 525 whether or not the injection valve operation region is a full injection valve operation region. In step 530, the individual correction value K (i) is already set for (n-1) fuel injection valves INJ (i), that is, for all the fuel injection valves INJ (i) except for one. It is determined whether or not is calculated.

  Only when both of the determination conditions in steps 525 and 530 are satisfied, the process proceeds to step 535, and the remaining correction is made based on the overall correction value Kave in step 510 and the individual correction value K (i) in step 520. The individual correction value K (i) for the fuel injection valve INJ (i) is calculated. After step 535, the process proceeds to step 540. If at least one of the determination conditions in steps 525 and 530 is not satisfied, the process returns to step 500.

  In Step 540 which has shifted from Step 520 or 535, it is determined whether or not the individual correction value K (i) has been calculated for all the fuel injection valves INJ (i). If this determination condition is not satisfied, the process returns to step 500, and if it is satisfied, the correction value calculation routine is terminated.

  On the other hand, in the engine 11 in which two fuel injection valves INJ (1) and INJ (2) are used per cylinder, the individual correction values K (1) and K (2) are, for example, the procedure shown in FIG. Is calculated according to

  First, in steps 600 to 615, the electronic control unit 51 performs the same processing as in steps 400 to 415. That is, in step 600, the total required injection amount Qth required for the fuel injection valve INJ (i) related to the injection at that time is read. In step 605, the actual injection amount Qreal for the fuel injection valve INJ (i) is calculated based on the operating state of the engine 11 such as the air-fuel ratio and the intake air amount. In step 610, the total correction value Kave is calculated by dividing the actual injection amount Qreal in step 605 by the total required injection amount Qth in step 600 according to the above-described equation (6). In step 615, the region determination map is referred to determine the injection valve operating region to which the engine speed NE and the engine load at that time belong, and the injection valve operating region determines one fuel injection valve INJ (1). It is determined whether or not it is a single injection valve operation region to be operated (indicated as INJ (1) operation region in FIG. 10). If this determination condition is satisfied, in step 620, the overall correction value Kave in step 610 is set (stored) as the individual correction value K (1) for the fuel injection valve INJ (1) according to the above equation (12). ) Then, after the process of step 620, the process proceeds to step 625.

  On the other hand, if the determination condition in step 615 is not satisfied, it is determined in step 630 whether or not the injection valve operation region is a full injection valve operation region. In step 635, it is determined whether the individual correction value K (1) for the fuel injection valve INJ (1) has already been calculated.

  Then, only when both of the determination conditions of Steps 630 and 635 are satisfied, the process proceeds to Step 640, and the fuel injection valve INJ (2) according to the following expression (13) obtained by modifying Expression (10) described above is performed. An individual correction value K (2) is calculated.

K (2) = (Kave * Qth−K (1) * Q (1)) / Q (2) (13)
After the processing of step 640, the process proceeds to step 625. If at least one of the determination conditions in steps 630 and 635 is not satisfied, the process returns to step 600.

  In step 625 which has shifted from step 620 or 640, the individual correction value K (1) for the fuel injection valve INJ (1) and the individual correction value K (2) for the fuel injection valve INJ (2) have already been calculated. Determine whether or not. If this determination condition is not satisfied, the process returns to step 600. If the determination condition is satisfied, the correction value calculation routine is terminated.

Therefore, according to the fourth embodiment, in addition to the effects (3), (4), and (7) described above, the following effect (8) according to the above (1) is obtained.
(8) Every time the injection valve operation region is switched to the single injection valve operation region in accordance with the operating state of the engine 11, the individual correction value K (i ) Is calculated. On the other hand, when the injection valve operation region is switched to the full injection valve operation region in accordance with the operating state of the engine 11, an overall correction value Kave is calculated. Based on the individual correction value K (i) and the overall correction value Kave, the individual correction value K (i) for the remaining one fuel injection valve INJ (i) is calculated. Therefore, by reflecting these individual correction values K (i) in the fuel injection control, the injection amount can be corrected under the general operation state of the engine 11 without creating a special operation state. Will be able to.

<Fifth Embodiment>
Next, a fifth embodiment embodying the present invention will be described. In the fifth embodiment, when the injection valve operating region is switched to the full injection valve operating region, the overall correction value Kave is calculated, and this calculation is performed under different operating conditions in the full injection valve operating region. Repeat as many times as the number of INJ (i). Based on the obtained overall correction value Kave, the individual required injection amount Q (i) and the total required injection amount Qth for the fuel injection valve INJ (i), the individual correction value for each fuel injection valve INJ (i). It is different from the first embodiment in that K (i) is calculated.

  This is due to the following circumstances. When calculating the individual correction value K (i), if the injection valve operation region is switched to the full injection valve operation region in accordance with the operating state of the engine 11, the entire correction for all fuel injection valves INJ (i) related to injection is performed. A value Kave is calculated. This calculation is performed based on the total required injection amount Qth and the actual injection amount Qreal according to the above equation (6). Accordingly, the actual injection amount Qreal can be expressed by the overall correction value Kave and the total required injection amount Qth.

  On the other hand, the overall actual injection amount Qreal is the same as the sum of the actual injection amounts Qreal of the individual fuel injection valves INJ (i). The individual actual injection amount Qreal can be represented by the individual correction value K (i) and the individual required injection amount Q (i) for each fuel injection valve INJ (i) according to the above equation (7). Here, the individual required injection amount Q (i) is separately calculated for controlling the fuel injection valve INJ (i). Accordingly, the individual required injection amount Q (i) is already known at the stage of calculating the overall correction value Kave. On the other hand, the individual correction value K (i) is unknown at the stage of calculating the overall correction value Kave.

  Therefore, in the relationship that the total actual injection amount Qreal and the sum of the actual injection amounts Qreal for each fuel injection valve INJ (i) are equal, the same number of individual correction values K as the number of fuel injection valves INJ (i). (I) is unknown. In order to clarify these unknown individual correction values K (i), the above-mentioned relationship is required as many as the number of fuel injection valves INJ (i).

  Therefore, as described above, the calculation of the total correction value Kave is performed at least as many times as the number of the fuel injection valves INJ (i) under different operating states in the total injection valve operation region, and the total correction value obtained is obtained. The individual correction value K (i) is calculated based on Kave and the like.

  The flowchart of FIG. 11 shows a series of processes performed when calculating the individual correction values K (1) and K (2) in the engine 11 using the two fuel injection valves INJ (1) and INJ (2). Is shown. These processes are executed every time the injection valve operation region becomes the entire injection valve operation region in accordance with the operating state of the engine 11. Here, the overall correction value Kave is calculated twice, which is the same number as the fuel injection valves INJ (1) and INJ (2). Therefore, in order to distinguish between the total correction value Kave calculated for the first time and the total correction value Kave calculated for the second time, the former is expressed as “Kave.1” and the latter is expressed as “Kave.2”. To do. Similarly, the individual required injection amounts Q (1), Q (2), the actual injection amount Qreal, and the total required injection amount Qth are the first ones, “Q (1) .1”, “Q (2)”. .1 "," Qreal.1 "," Qth.1 ", and the second one is" Q (1) .2 "," Q (2) .2 "," Qreal.2 "," Qth.2 ".

  In steps 700 to 710, the electronic control unit 51 performs a process of calculating the first overall correction value Kave.1. In step 700, the total required injection amount Qth.1 required for both fuel injection valves INJ (1) and INJ (2) is read. In step 705, the actual injection amount Qreal.1 for the fuel injection valves INJ (1) and INJ (2) is calculated based on the operating state of the engine 11 such as the air-fuel ratio and the intake air amount. In step 710, the overall correction value Kave.1 is calculated by dividing the actual injection amount Qreal.1 in step 705 by the total required injection amount Qth.1 in step 700 in accordance with the equation (6) described above. To do.

  The total correction value Kave.1, the total required injection amount Qth.1, the individual correction values K (1), K (2), and the individual required injection amount Q (1) .1, Q (2). During 1, the equation expressed by the following equation (14) is established. This equation (14) follows the equation (10) described above. In equation (14), Kave.1, Qth.1, Q (1) .1, Q (2) .1 are known, and K (1), K (2) are unknown.

Kave.1 * Qth.1 = K (1) * Q (1) .1 + K (2) * Q (2) .1
(14)
Subsequently, in step 715, it is determined whether or not the operating conditions of the engine 11 have changed under the entire injection valve operating region. If this determination condition is not satisfied, the process returns to step 700. If the determination condition is satisfied, in step 720 to 730, a process for calculating the second total correction value Kave.2 is performed. In step 720, the total required injection amount Qth.2 required for both fuel injection valves INJ (1) and INJ (2) is read. In step 725, the actual injection amount Qreal.2 for the fuel injection valves INJ (1) and INJ (2) is calculated based on the operating state of the engine 11 such as the air-fuel ratio and the intake air amount. In step 730, the overall correction value Kave.2 is calculated by dividing the actual injection amount Qreal.2 in step 725 by the total required injection amount Qth.2 in step 720 according to the above-described equation (6). To do.

  The total correction value Kave.2, the total required injection amount Qth.2, the individual correction values K (1), K (2) and the individual required injection amount Q (1) .2, Q (2). Between 2, the equation represented by the following equation (15) holds. In equation (15), Kave.2, Qth.2, Q (1) .2, Q (2) .2 are known, and K (1) and K (2) are unknown.

Kave.2 * Qth.2 = K (1) * Q (1) .2 + K (2) * Q (2) .2
(15)
Subsequently, in step 735, unknown individual correction values K (1) and K (2) are obtained by solving the two equations (14) and (15). Then, after the processing of step 735, the correction value calculation routine is terminated.

Therefore, according to the fourth embodiment, in addition to the effects (3), (4), and (7) described above, the following effect (9) according to the above (1) is obtained.
(9) Calculation of the overall correction value Kave is performed at least as many times as the number of fuel injectors INJ (i) under different operating states in the entire injector operating region, and a plurality of obtained equations are solved. Thus, the individual correction value K (i), which is an unknown value, is calculated. Therefore, by reflecting these individual correction values K (i) in the fuel injection control, the injection amount can be corrected under the general operation state of the engine 11 without creating a special operation state. Is possible.

Note that the present invention can be embodied in another embodiment described below.
-In 2nd Embodiment, you may change the determination value used for determination of step 185 of FIG. 5, and step 270 of FIG. 6 into a value different from said "1". When it is desired to calculate the individual correction value K (i) many times, the determination value is set to a large value.

  In the fifth embodiment, the procedure for calculating the individual correction values K (1) and K (2) in the engine 11 using the two fuel injection valves INJ (i) has been described. In addition, the individual correction value K (i) can be calculated by performing the same process on the engine 11 in which three or more fuel injection valves INJ (i) are used. However, in this case, it is necessary to perform the process of calculating the overall correction value Kave n times or more under the entire injection valve operating region.

  In the third to fifth embodiments, as in the first and second embodiments, it is determined whether or not the condition (k> α) for calculating the individual correction value K (i) is satisfied, and is satisfied. However, the process of calculating the individual correction value K (i) may be permitted only if the

  The determination condition in step 615 in FIG. 10 may be changed to “whether it is a single injection valve operation region where the other fuel injection valve INJ (2) is to be operated” instead of the above-described one.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the structure about 1st Embodiment which actualized this invention. The flowchart which shows the procedure which calculates the individual correction value K (i) about the engine in which n fuel-injection valves were provided per cylinder. The flowchart which shows the procedure which calculates the individual correction value K (1) and K (2) about the engine provided with two fuel injection valves per cylinder. 9 is a flowchart showing a procedure for calculating an individual correction value K (i) for an engine provided with n fuel injection valves per cylinder in the second embodiment. The flowchart which similarly shows the procedure which calculates the individual correction value K (i). 9 is a flowchart showing a procedure for calculating individual correction values K (1) and K (2) for an engine provided with two fuel injection valves per cylinder in the second embodiment. The flowchart which shows the procedure which calculates the individual correction value K (i) about the engine in which n fuel-injection valves were provided per cylinder in 3rd Embodiment. 9 is a flowchart showing a procedure for calculating individual correction values K (1) and K (2) for an engine provided with two fuel injection valves per cylinder in the third embodiment. The flowchart which shows the procedure which calculates the individual correction value K (i) about the engine in which n fuel injection valves were provided per cylinder in 4th Embodiment. 9 is a flowchart showing a procedure for calculating individual correction values K (1) and K (2) for an engine provided with two fuel injection valves per cylinder in the fourth embodiment. The flowchart which shows the procedure which calculates individual correction value K (1) and K (2) about the engine in which 2 fuel-injection valves were provided per cylinder in 5th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Gasoline engine (internal combustion engine), 12 ... Cylinder, 22 ... Intake passage, 43 ... Intake air amount sensor (intake air amount detection means), 44 ... Air-fuel ratio sensor (air-fuel ratio detection means), 51 ... Electronic control unit ( (Correction value calculation means), INJ (i), INJ (1), INJ (2) ... fuel injection valve, k ... flow rate reduction rate, α ... reference value, K (i), K (1), K (2) ... individual correction value, Kave ... total correction value, Q (i), Q (1), Q (2) ... individual required injection amount, Qth ... total required injection amount, Qreal ... actual injection amount.

Claims (6)

  A plurality of fuel injection valves are provided per cylinder, and the fuel injection valve corresponding to the injection valve operating region that is switched according to the engine operating state is used for an internal combustion engine that uses a fuel injection valve related to injection,
  Correction value calculation means for calculating a correction value for compensating for a deviation between the required injection amount and the actual injection amount according to the engine operating state is provided, and the correction value by the correction value calculation means is reflected in the fuel injection control. A fuel injection control device for an internal combustion engine,
  The correction value calculation means is the same for all the single injection valve operating areas in which fuel is injected by a single fuel injection valve, except that the injection valve operating area is the same according to the engine operating state. Each time the operation is switched to one injection valve operation region, an individual correction value for the fuel injection valve in the same single injection valve operation region is calculated, and the injection valve operation region is used for all fuel injection valves to operate. An overall correction value for the fuel injection valve is calculated on the condition that the injection valve operating region is switched, and based on these individual correction values and the overall correction value, individual correction values for the remaining fuel injection valves are calculated. Calculate
  A fuel injection control device for an internal combustion engine.   A plurality of fuel injection valves are provided per cylinder, and the fuel injection valve corresponding to the injection valve operating region that is switched according to the engine operating state is used for an internal combustion engine that uses a fuel injection valve related to injection,
  Correction value calculation means for calculating a correction value for compensating for a deviation between the required injection amount and the actual injection amount according to the engine operating state is provided, and the correction value by the correction value calculation means is reflected in the fuel injection control. A fuel injection control device for an internal combustion engine,
  The correction value calculation means calculates an overall correction value for all the fuel injection valves when the injection valve operation region is switched to an all injection valve operation region in which fuel is injected by all the fuel injection valves. This calculation is performed at least as many times as the number of fuel injectors under different engine operating conditions in the entire injection valve operating region, and the obtained overall correction values and the individual and overall requirements for the fuel injectors. Calculate individual correction values for each fuel injection valve based on the injection amount
  A fuel injection control device for an internal combustion engine.   The fuel injection control device for an internal combustion engine according to claim 1 or 2,
  An air-fuel ratio detecting means for detecting the air-fuel ratio of the air-fuel mixture based on the concentration of oxygen in the exhaust; and an intake air amount detecting means for detecting the intake air amount, wherein the correction value calculating means comprises the air-fuel ratio detecting means The actual injection amount calculated based on the air-fuel ratio by the intake air amount and the intake air amount by the intake air amount detection means is used to calculate the correction value.
  A fuel injection control device for an internal combustion engine.   The fuel injection control device for an internal combustion engine according to any one of claims 1 to 3,
  The correction value calculation means sets the ratio between the actual injection amount and the required injection amount as the correction value.
  A fuel injection control device for an internal combustion engine.   The fuel injection control device for an internal combustion engine according to any one of claims 1 to 4,
  The correction value calculation means compares the required injection amount for the fuel injection valve with the actual injection amount in the injection valve operation region according to the engine operating state, and the actual injection amount changes by more than a predetermined reference value with respect to the required injection amount. The correction value is calculated on the condition that
  A fuel injection control device for an internal combustion engine.   The fuel injection control device for an internal combustion engine according to any one of claims 1 to 5,
  The fuel injection valve for each cylinder includes a fuel injection valve that injects fuel into the intake passage and a fuel injection valve that directly injects fuel into the cylinder.
  A fuel injection control device for an internal combustion engine.

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