JP4853503B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention includes, for example, a plurality of cylinder rows, a fuel injection valve that is provided for each cylinder constituting the cylinder row and injects fuel into the cylinder, and a cylinder that constitutes the cylinder row, such as a V-type engine. Applied to an internal combustion engine having air-fuel ratio detection means for detecting the air-fuel ratio of exhaust gas exhausted for each cylinder, the learning value of the alcohol concentration contained in the fuel injected from the fuel injection valve through air-fuel ratio feedback control is obtained. The present invention relates to a control device for an internal combustion engine that is updated for each cylinder row.

  Conventionally, as a control device of this type of internal combustion engine, for example, there is one described in Patent Document 1. In an internal combustion engine to which such a control device is applied, including the one described in Patent Document 1, for example, a mixture fuel in which gasoline fuel and alcohol fuel are mixed is injected from a fuel injection valve. In such an internal combustion engine, in order to calculate the fuel injection amount according to the alcohol concentration contained in the fuel, it is necessary to quickly learn when the alcohol concentration changes. Therefore, at the time of engine operation after refueling, the learned value of alcohol concentration is updated based on the air-fuel ratio feedback correction value calculated through air-fuel ratio feedback control. That is, since alcohol fuel has a smaller output per unit volume obtained through combustion than gasoline fuel, it is necessary to increase the fuel injection amount as the concentration of alcohol contained in the fuel increases. Therefore, for example, when the actual alcohol concentration at that time is larger than the learned value of the alcohol concentration, the fuel injection amount becomes insufficient, and the air-fuel ratio of the exhaust gas becomes a leaner value than the target air-fuel ratio. . At this time, a larger value is calculated as the air-fuel ratio feedback correction value so that the air-fuel ratio of the exhaust gas matches the target air-fuel ratio through the air-fuel ratio feedback control. From these facts, the learned value of alcohol concentration can be updated in accordance with the actual alcohol concentration by updating the learned value of alcohol concentration based on the air-fuel ratio feedback correction value.

  By the way, in a V-type engine, for example, an air-fuel ratio sensor is usually provided for each exhaust passage connected to the left and right banks. Therefore, the air-fuel ratio feedback control and the alcohol concentration learning value update control described above are performed on the left and right sides. This is done for each bank.

Here, if the actual alcohol concentration is the same in the left and right banks, the learned value of the alcohol concentration should be updated as the same value in the left and right banks. On the other hand, there are individual differences in the air-fuel ratio sensors, and their output signals vary, so that the output signals of the air-fuel ratio sensors are in the left and right directions even though the actual alcohol concentration is equal in the left and right banks. Different values are obtained in the banks, and as a result, the learning value of the alcohol concentration is also updated as different values in the left and right banks. Therefore, for example, by calculating an average value of each learned value of the alcohol concentration updated for each of the left and right banks, an error in the learned value of the alcohol concentration caused by variations in the output signal of the air-fuel ratio sensor is reduced. Yes. Further, the fuel injection amount is calculated based on the average value of the learned alcohol concentration value thus calculated.
JP 2008-51063 A

  However, in the configuration in which the fuel injection amount is calculated based on the average value of each learned value of the alcohol concentration updated for each of the left and right banks, the following problem occurs. That is, during engine operation after refueling, the actual alcohol concentration differs between the left and right banks, but when the above-described learning value update control for alcohol concentration is executed from this state, the actual alcohol concentration subsequently changes to the left and right banks. When the values become equal in each bank, the learning values of the alcohol concentration updated for each of the left and right banks are in a state of being deviated from the actual alcohol concentration.

  Here, an example will be described with reference to FIG. In this case, fuel is supplied to the fuel injection valves in the left and right banks as a configuration in which the above-described problem becomes significant, that is, a configuration in which the actual alcohol concentration differs greatly between the left and right banks during engine operation after refueling. Among the fuel pipes to be performed, a configuration in which the fuel pipe for the left bank is arranged upstream of the fuel pipe for the right bank in the fuel supply system will be described.

  FIG. 5 is a timing chart that also shows changes in various parameters during engine operation after refueling. (A) Change in alcohol concentration CALCL contained in fuel in the left bank, (b) Include in fuel in the right bank. Transition of alcohol concentration CALCR, (c) Transition of air-fuel ratio feedback correction value FAFL in the left bank, (d) Transition of learned value ALCGL of alcohol concentration in the left bank, (e) Transition of air-fuel ratio feedback correction value FAFR in the right bank , (F) Transition of the learning value ALCGL of the alcohol concentration in the right bank, and (g) Transition of the average value ALCGAVE (= (ALCGL + ALCGR) / 2) of the learning value of the alcohol concentration updated for each of the left and right banks. . In the figure, the case where the concentration of alcohol contained in the fuel increases from “0%” to “X1%” before and after refueling is shown.

  As shown in the figure, in the left bank, the alcohol concentration CALCL contained in the fuel increases after timing t11 (FIG. 5 (a)). On the other hand, since the fuel piping for the right bank is arranged downstream of the fuel piping for the left bank in the fuel supply system, the fuel after refueling has not yet arrived in the right bank, and for a while The alcohol concentration CALCR remains “0%” and does not change (FIG. 5B).

  At this time, the learned values ALCGL and ALCGR of the alcohol concentration are not updated, and are based on the average value ALCGAVE (in this case, “0%”) of the learned values ALCGL and ALCGR of the alcohol concentration updated during the previous engine operation. Thus, the fuel injection amount is calculated. Therefore, in the left bank, the increase in the alcohol concentration CALCL is not taken into account, so that the fuel becomes insufficient. As a result, the air-fuel ratio feedback correction value FAFL increases rapidly (FIG. 5C), and the alcohol concentration learning value ALCGL updated based on the air-fuel ratio feedback correction value FAFL increases rapidly. (FIG. 5D). On the other hand, in the right bank, the learned value ALCGR of the alcohol concentration is maintained at the previous value “0%” (FIG. 5F). Therefore, the average value ALCGAVE (= (ALCGL + ALCGR) / 2) of the learning values of the alcohol concentration is calculated as a half value (= ALCGL / 2) of the learning value ALCGL of the alcohol concentration in the left bank (FIG. 5 (g )).

  Next, in the period up to the timing t12 when the alcohol concentration CALCL contained in the fuel increases in the right bank, each learning of the alcohol concentration is performed in the right bank even though the alcohol concentration CALCR does not increase. The fuel injection amount is calculated on the basis of the average value ALCGAVE of the values, that is, half of the learned value ALCGL of the alcohol concentration in the left bank. Therefore, in the right bank, the fuel becomes excessive, and the air-fuel ratio feedback correction value FAFR rapidly decreases (FIG. 5 (e)). Here, the learned value ALCGR of the alcohol concentration that is updated based on the air-fuel ratio feedback correction value FAFR tends to rapidly decrease, but is “0%” that is the lower limit value of the learned value ALCGR of the alcohol concentration. Therefore, it does not actually decrease further (FIG. 5 (f)).

  On the other hand, in the left bank, after the timing t11, since the average value ALCGAVE of the learning values of the alcohol concentration continues to be higher than the actual alcohol concentration CALCL, the fuel shortage state continues. As a result, the alcohol concentration learning value ALCGL increases before the actual alcohol concentration CALCL increases (FIGS. 5A and 5D).

  In the right bank, the alcohol concentration CALCR contained in the fuel increases after the timing t12 (FIG. 5A), but for a while, the fuel injected to the actual alcohol concentration CALCR. As a result, the air-fuel ratio feedback correction value FAFR becomes lower than “0” (FIG. 5E). Therefore, the learned value ALCGR of the alcohol concentration is continuously maintained at “0%” (FIG. 5 (f)). Then, when the actual alcohol concentration CALCR in the right bank further increases (FIG. 5B) and approaches the average value ALCGAVE of each learned value of alcohol concentration, the air-fuel ratio feedback correction value FAFR increases. Will come to do. When the air-fuel ratio feedback correction value FAFR exceeds “0” after timing t13 (FIG. 5E), the alcohol concentration learning value ALCGR increases with a delay from the actual increase of the alcohol concentration CALCR. (FIGS. 5B and 5F).

  Thus, in the left bank, the alcohol concentration learning value ALCGL increases prior to the increase in the actual alcohol concentration CALCL, whereas in the right bank, the alcohol concentration learning value is delayed from the increase in the actual alcohol concentration CALCR. ALCGR will increase. Therefore, after that, when the actual alcohol concentrations CALCL and CALCR become equal in the left and right banks, the learned value ALCGL of the alcohol concentration in the left bank diverges to the side larger than the actual alcohol concentration CALCR, and the alcohol concentration in the right bank This learning value ALCGR is in a state of being deviated to a side smaller than the actual alcohol concentration. As a result, there arises a problem that it takes a long time to update the alcohol concentration learning values ALCGL and ALCGR to values corresponding to the actual alcohol concentrations CALCL and CALCR through the alcohol concentration learning value update control. .

  Such a problem is not limited to the V-type engine, and includes a plurality of cylinder rows, a fuel injection valve that is provided for each cylinder constituting the cylinder row and supplies fuel to the cylinder, and the cylinder row. As long as the internal combustion engine is provided with air-fuel ratio detection means for detecting the air-fuel ratio of the exhaust gas discharged from each cylinder row for each cylinder row, this can occur in common with other control apparatuses for the internal combustion engine.

  Further, such a problem is not limited to an internal combustion engine in which a plurality of fuel pipes that are provided for each of a plurality of cylinder rows and respectively supply fuel to corresponding fuel injection valves are connected in series. If the state in which the alcohol concentration contained in the fuel injected from the fuel injection valve is different for each of the plurality of cylinder rows sometimes occurs, the control devices for other internal combustion engines are also more or less common. Can occur.

  Further, such a problem is not limited to the control device that calculates the fuel injection amount based on the average value of each learned value of the alcohol concentration updated for each cylinder row, but the alcohol concentration updated for each cylinder row is not limited. As long as it is a control device that calculates the fuel injection amount based on a value between the learning values, it can occur in other control devices as well.

  The present invention has been made in view of such circumstances, and the purpose thereof is the time required for the learning value of the alcohol concentration to be updated to a value corresponding to the actual alcohol concentration through the alcohol concentration learning value update control. An object of the present invention is to provide a control device for an internal combustion engine that can shorten the engine speed.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is exhausted from a plurality of cylinder rows, a fuel injection valve provided for each cylinder constituting the cylinder row and supplying fuel to the cylinder, and a cylinder constituting the cylinder row. Applied to an internal combustion engine having an air-fuel ratio detecting means for detecting the air-fuel ratio of the exhaust gas for each cylinder row, and based on the tendency of the difference between the air-fuel ratio of the exhaust detected by the air-fuel ratio detecting means and the target air-fuel ratio. From the fuel injection valve based on the air-fuel ratio correction value calculated by the air-fuel ratio correction value calculating means calculated by the air-fuel ratio correction value calculating means for calculating the air-fuel ratio correction value of the fuel injection amount for each of the plurality of cylinder rows Learning value updating means for updating the learning value of the alcohol concentration contained in the injected fuel for each cylinder row, and each learning value of the alcohol concentration updated for each cylinder row by the learning value updating means. Based on the value between In the control device for an internal combustion engine that calculates the fuel injection amount, the control device includes a determination unit that determines whether or not the alcohol concentration contained in the fuel injected from the fuel injection valve is equal in the plurality of cylinder rows, The learning value updating means is configured to determine that the alcohol concentration contained in the fuel injected from the fuel injection valve is equal in the plurality of cylinder rows by the determination means during engine operation after refueling. The gist is to change the learning value of at least one of the plurality of cylinder rows so as to approach the average value of the learning values immediately before the alcohol concentration updated for each cylinder row.

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the learned value update means changes each learned value of the alcohol concentration for both of the plurality of cylinder rows. Is the gist.

  The invention according to claim 3 is the control device for an internal combustion engine according to claim 1 or 2, wherein the learning value update means is configured to provide each learning value of the alcohol concentration for both of the plurality of cylinder rows. Is changed to an average value of learning values immediately before the alcohol concentration updated for each cylinder row.

  According to the configuration of the first, second, and third aspects, the alcohol concentration contained in the fuel injected from the fuel injection valve becomes equal in the plurality of cylinder rows during engine operation after refueling. When the determination is made, the learning value of the alcohol concentration is changed for at least one of the plurality of cylinder rows so as to approach the average value of the learning values immediately before the alcohol concentration updated for each cylinder row. As a result, even if a cumulative error has occurred in the learning value of the alcohol concentration, each learning value of the alcohol concentration can be brought close to the actual alcohol concentration. Accordingly, it is possible to shorten the time required for the learning value of the alcohol concentration to be updated to a value corresponding to the actual alcohol concentration through the alcohol concentration learning value update control.

  According to a fourth aspect of the present invention, in the control device for an internal combustion engine according to any one of the first to third aspects, fuel is supplied to the corresponding fuel injection valve provided for each of the plurality of cylinder rows. The gist is that a plurality of fuel pipes to be supplied are connected in series.

  In the configuration in which the plurality of fuel pipes provided for each of the plurality of cylinder rows are connected in series, the cylinder row corresponding to the fuel pipe arranged on the upstream side in the fuel supply system and the downstream side during engine operation after refueling The actual alcohol concentration differs greatly from the cylinder row corresponding to the fuel pipe arranged on the side. Therefore, even after that, even when the actual alcohol concentration becomes equal in a plurality of cylinder rows, in the upstream cylinder row in the fuel supply system, the learned value of the alcohol concentration is larger than the actual alcohol concentration. In the downstream cylinder row, there is a tendency that the learned value of the alcohol concentration deviates to a side smaller than the actual alcohol concentration. As a result, there arises a problem that it takes a longer time until the learned value of the alcohol concentration is updated to a value corresponding to the actual alcohol concentration through the learning value update control of the alcohol concentration.

  If the invention according to any one of claims 1 to 3 is applied to the control device for an internal combustion engine having such a premise configuration, the learning value of the alcohol concentration is obtained in the upstream cylinder row. Is changed to be smaller than the value updated immediately before, and in the downstream cylinder row, the learning value of the alcohol concentration is changed to be larger than the value updated immediately before. Through these things, the learning value of the alcohol concentration can be brought close to the actual alcohol concentration. Accordingly, it is possible to shorten the time required for the learning value of the alcohol concentration to be updated to a value corresponding to the actual alcohol concentration through the alcohol concentration learning value update control.

  In the invention according to any one of claims 1 to 4, as in the invention according to claim 5, the determination means has an elapsed period from the start of the engine after the fueling is a predetermined period or more. Accordingly, the embodiment can be embodied in such a manner that the alcohol concentration contained in the fuel injected from the fuel injection valve is determined to be equal in the plurality of cylinder rows.

The gist of a sixth aspect of the invention is the control apparatus for an internal combustion engine according to the fifth aspect, wherein the determination means variably sets the predetermined period according to the engine operating state.
According to this configuration, during engine operation after refueling, the predetermined period for determining whether the alcohol concentration contained in the fuel injected from the fuel injection valve is equal in the plurality of cylinder rows is equal to engine operation. It is variably set according to the state. For this reason, for example, when the time required for the alcohol concentration contained in the fuel injected from the fuel injection valve to be equal in the plurality of cylinder rows is short, such as when the amount of fuel injection injected from the fuel injection valve is large. If the predetermined period is set short, the predetermined period can be set accurately small. Therefore, it is possible to further reduce the time required for the learning value of the alcohol concentration to be updated to a value corresponding to the actual alcohol concentration through the alcohol concentration learning value update control.

The gist of the invention according to claim 7 is the control device for an internal combustion engine according to any one of claims 1 to 6, wherein the internal combustion engine comprises two cylinder rows. .
The control apparatus for an internal combustion engine according to any one of claims 1 to 6 is embodied in such a manner that the internal combustion engine includes two cylinder rows as in the invention according to claim 7. can do. As such an internal combustion engine, a V-type cylinder arrangement in which an angle between two cylinder rows is smaller than 180 degrees, or a horizontally opposed cylinder in which an angle between two cylinder rows is 180 degrees The thing of arrangement | sequence etc. can be mentioned.

  1 to 4, an internal combustion engine control apparatus according to the present invention uses an in-vehicle V-type 8-cylinder engine (hereinafter referred to as "engine 1") for injecting a mixed fuel composed of gasoline fuel and ethanol fuel. An embodiment embodied as the control device will be described in detail.

  FIG. 1 schematically shows a schematic configuration of the engine 10 and an electronic control unit 50 that controls the engine 10. FIG. 2 shows a schematic configuration of a fuel supply system of the engine 10 and an electronic control unit 50 that controls the fuel supply system.

  As shown in FIG. 1, the engine 10 includes a left bank 11 as a cylinder row having four cylinders 12a to 12d and a right bank 21 as a cylinder row having four cylinders 22a to 22d. Yes. The cylinders 12a to 12d and 22a to 22d are respectively provided with spark plugs 13a to 13d and 23a to 23d for igniting the air-fuel mixture.

  An intake manifold 31 is connected to each cylinder 12 a to 12 d of the left bank 11 via an intake port (not shown), and a left intake passage 33 is connected to the intake upstream side of the intake manifold 31.

  An intake manifold 32 is connected to each cylinder 22 a to 22 d of the right bank 21 via an intake port (not shown), and a right intake passage 34 is connected to the intake upstream side of the intake manifold 32.

  A common intake passage 35 is commonly connected to the left intake passage 33 and the right intake passage 34 on the intake upstream side thereof. A throttle valve 36 for metering the intake air is provided in the middle of the common intake passage 35. The throttle valve 36 is provided with a throttle motor 37 for opening and closing the throttle valve 36.

  Further, an exhaust manifold 41 is connected to each cylinder 12 a to 12 d of the left bank 11 via an exhaust port (not shown), and a left exhaust passage 43 is connected to the exhaust downstream side of the exhaust manifold 41. .

  In addition, an exhaust manifold 42 is connected to each cylinder 22a to 22d of the right bank 21 via an exhaust port (not shown), and a right exhaust passage 44 is connected to the exhaust downstream side of the exhaust manifold 42. .

Next, the configuration of the fuel supply system of the engine 10 will be described in detail with reference to FIG.
A fuel pump module 72 is provided inside the fuel tank 71. The fuel pump module 72 includes a reservoir cup 73, an electric feed pump 74, a fuel filter 75, and a low pressure pressure regulator 83. A feed pump 74 and a fuel filter 75 are provided inside the reservoir cup 73. The fuel pressurized by the feed pump 74 is sent to the fuel filter 75 through the check valve 74a and the fuel path 74b, and further sent to the main path 76 through the check valve 75a. A left fuel pipe 77, a fuel communication path 78, and a right fuel pipe 79 are connected in series to the main path 76 in order from the upstream side in the fuel flow direction, and pressurized fuel from the feed pump 74 passes through the main path 76. The left fuel pipe 77 and the right fuel pipe 79 are supplied in this order. More specifically, the fuel supplied through the main path 76 flows from the base end portion (the right end portion in FIG. 2) of the left fuel pipe 77 toward the tip end portion (the left end portion in FIG. 2). Is introduced into the base end portion (left end portion in FIG. 2) of the right fuel pipe 79 through the fuel communication path 78 and flows from the base end portion of the right fuel pipe 79 toward the tip end portion (right end portion in FIG. 2). ing.

  Four fuel injection valves 14a to 14d are connected to the left fuel pipe 77, and these fuel injection valves 14a to 14d supply fuel to the intake ports of the cylinders 12a to 12d of the left bank 11 shown in FIG. Each is configured to be supplied by injection.

  Four fuel injection valves 24a to 24d are connected to the right fuel pipe 79, and these fuel injection valves 24a to 24d supply fuel to the intake ports of the respective cylinders 22a to 22d of the right bank 21 shown in FIG. Each is configured to inject.

  A first return path 80 is connected to the base end portion of the right fuel pipe 79. The first return path 80 is provided with a high pressure regulator 82 through which the fuel in the main path 76, the left fuel pipe 77, the fuel communication path 78, and the right fuel pipe 79 passes through a high pressure (for example, , About 400 kPa). When the fuel pressure in the main path 76, the left fuel pipe 77, the fuel communication path 78, and the right fuel pipe 79 exceeds a predetermined pressure (about 400 kPa), excess fuel passes through the high-pressure pressure regulator 82 to the first return path 80. To the fuel tank 71.

  In the middle of the main path 76, specifically, at a position adjacent to the fuel pump module 72, a second return path 81 is branched from the main path 76. The second return path 81 is provided with a low pressure regulator 83 through which the fuel in the main path 76, the left fuel pipe 77, the fuel communication path 78, and the right fuel pipe 79 passes through a low pressure (for example, , About 280 kPa). When the fuel pressure in the main path 76, the left fuel pipe 77, the fuel communication path 78, and the right fuel pipe 79 exceeds a predetermined pressure (about 280 kPa), excess fuel passes through the low pressure regulator 83 and the second return path 81. To the fuel tank 71.

  Further, in the second return path 81, an electromagnetically driven fuel pressure switching valve 84 is provided between a branch portion with the main path 76 and the low pressure regulator 83. When the fuel pressure switching valve 84 is closed, the low-pressure pressure regulator 83 does not function, so the fuel pressure inside the main path 76, left fuel pipe 77, fuel communication path 78, and right fuel pipe 79 is high pressure. It is regulated to a high pressure through the regulator 82. For this reason, fuel injection on the high-pressure side is performed from the fuel injection valves 14a to 14d and 24a to 24d at each fuel injection timing. Further, when the fuel pressure switching valve 84 is in the open state, the low pressure regulator 83 functions in preference to the high pressure regulator 82, and the main path 76, the left fuel pipe 77, and the fuel communication path through the low pressure regulator 83. The fuel pressure inside 78 and the right fuel pipe 79 is adjusted to a low pressure. For this reason, fuel injection on the low pressure side is performed from the fuel injection valves 14a to 14d and 24a to 24d at each fuel injection timing. The fuel pressure can be switched by opening and closing the fuel pressure switching valve 84 as described above.

  The engine 10 is provided with various sensors for detecting the operating state. That is, as shown in FIG. 1, an engine rotation speed sensor 61 for detecting the engine rotation speed NE and an intake air amount sensor 62 for detecting the intake air amount GA are provided. A throttle opening sensor 63 for detecting the opening of the throttle valve 36 (hereinafter referred to as “throttle opening TA”) is provided in the vicinity of the throttle valve 36. In addition, an accelerator opening sensor 64 that detects the amount of operation of the accelerator pedal (hereinafter referred to as “accelerator opening ACCP”) and a water temperature sensor that detects the temperature of the cooling water of the engine 10 (hereinafter referred to as “cooling water temperature THW”). 65 is provided. The left exhaust passage 43 is provided with a left air-fuel ratio sensor 66 for detecting an air-fuel ratio AFL of exhaust discharged from the cylinders 12a to 12d constituting the left bank 11, and the right exhaust passage 44 is provided with the right bank 21. A right air-fuel ratio sensor 67 for detecting an air-fuel ratio AFR of exhaust exhausted from the cylinders 22a to 22d constituting the engine is provided. In addition to these sensors, various sensors are provided as necessary. The detection signals of these sensors 61 to 67 are input to the electronic control unit 50 that executes various controls of the engine 10.

  The electronic control device 50 is configured to include a program for executing various controls, a calculation map, and a memory that stores various data calculated when the control is executed, and includes the sensors 61 to 67 described above. For example, the following controls are executed based on the engine operating state and the like ascertained from the output values of the various sensors. That is, the throttle control for controlling the throttle valve 36, the fuel injection control for controlling the fuel injection valves 14a to 14d and 24a to 24d, the ignition timing control for controlling the spark plugs 13a to 13d and 23a to 23d, and the fuel pressure switching valve 84 are provided. Execute fuel pressure control to control opening and closing. Also, the air-fuel ratio feedback correction values FAFL and FAFR of the fuel injection amount are set to the left and right banks based on the tendency of deviation between the air-fuel ratios AFL and AFR of the exhaust detected by the left and right air-fuel ratio sensors 66 and 67, respectively. Air-fuel ratio feedback control calculated for each of 11 and 21 is executed. Further, based on the air-fuel ratio feedback correction values FAFL and FAFR, the learned values ALCGL and ALCGR of the alcohol concentration contained in the fuel injected from the fuel injectors 14a to 14d and 24a to 24d are updated for each of the left and right banks 11 and 21. The alcohol concentration learning value update control is executed.

  Here, in the fuel pressure control, the fuel pressure switching valve 84 is closed and the fuel pressure is controlled to a high pressure when the engine is in an engine operating state where it is necessary to increase the fuel injection amount at the time of starting the engine. Even when the fuel injection amount is not increased, for example, when the alcohol concentration in the fuel supply system is uneven, such as during engine operation after refueling, the fuel pressure switching valve 84 is closed and the fuel pressure is changed. , And the fuel existing in the main path 76 and the fuel pipes 77 and 79 is returned to the fuel tank 71 through the high-pressure pressure regulator 82 and the first return path 80. As a result, a state in which the alcohol concentration in the fuel supply system is not uniform is quickly eliminated. In this case, the valve opening period of the fuel injection valve is appropriately set so that the fuel injection amount becomes a normal fuel injection amount while the fuel pressure is controlled to be high. On the other hand, in a normal engine operation state where it is not necessary to increase the fuel injection amount, the fuel pressure switching valve 84 is opened to control the fuel pressure to a low pressure.

  In the air-fuel ratio feedback control, for example, all execution conditions such as when the engine is not started, fuel cut is not performed, the coolant temperature THW is equal to or higher than a predetermined temperature, and the air-fuel ratio sensors 66 and 67 are activated are satisfied. When it is executed. In the air-fuel ratio feedback control, in order to reduce the difference between the output voltages VAFL and VAFR of the air-fuel ratio sensors 66 and 67 and the predetermined voltage VTRG corresponding to the target air-fuel ratio AFTRG (hereinafter referred to as “voltage difference ΔV”), Based on ΔV, feedback correction values FAFL and FAFR for feedback control of the air-fuel ratios AFL and AFR of the air-fuel mixture in the left and right banks 11 and 21 are calculated for each of the left and right banks 11 and 21. Specifically, the output voltages VAFL and VAFR of the air-fuel ratio sensors 66 and 67 are, as the oxygen concentration of the exhaust gas increases, that is, the air-fuel ratios AFL and AFR of the air-fuel mixture deviate toward the lean side with respect to the target air-fuel ratio AFTRG. As it grows. Further, the output voltages VAFL and VAFR of the air-fuel ratio sensors 66 and 67 become smaller as the oxygen concentration of the exhaust gas becomes lower, that is, as the air-fuel ratios AFL and AFR of the air-fuel mixture deviate toward the rich side with respect to the target air-fuel ratio AFTRG. . Therefore, in the air-fuel ratio feedback control, the output voltages VAFL, VAFR of the air-fuel ratio sensors 66, 67 are compared with the predetermined voltage VTRG, and when the output voltages VAFL, VAFR are larger than the predetermined voltage VTRG, that is, the air-fuel ratio of the air-fuel mixture When it is determined that AFL and AFR are on the lean side of the target air-fuel ratio AFTRG, a value obtained by adding a predetermined value to the air-fuel ratio feedback correction values FAFL and FAFR at that time is set as the new air-fuel ratio feedback correction values FAFL and FAFR. Calculate as On the other hand, when the output voltages VAFL, VAFR are equal to or lower than the predetermined voltage VTRG, that is, when it is determined that the air-fuel ratio AFL, AFR of the air-fuel mixture is on the rich side with respect to the target air-fuel ratio AFTRG, the air-fuel ratio feedback at that time Values obtained by subtracting a predetermined value from the correction values FAFL and FAFR are calculated as new air-fuel ratio feedback correction values FAFL and FAFR.

  The alcohol concentration learning value update control is executed when air-fuel ratio feedback control is being executed. In the alcohol concentration learning value update control, the alcohol concentration learning values ALCGL and ALCGR are set to the left and right banks 11 and 21 based on the air / fuel ratio feedback correction values FAFL and FAFR calculated through the air / fuel ratio feedback control during engine operation after refueling. Update to This is because if the fuel supply is performed, the alcohol concentration in the fuel supply system is likely to change accordingly. That is, since alcohol fuel has a smaller output per unit volume obtained through combustion than gasoline fuel, it is necessary to increase the fuel injection amount as the concentration of alcohol contained in the fuel increases. Therefore, for example, when the actual alcohol concentrations CALCL and CALCR at that time are larger than the alcohol concentration learning values ALCGL and ALCGR, the fuel injection amount becomes insufficient, and the air-fuel ratios AFL and AFR of the exhaust gas are equal to the target air. The value is leaner than the fuel ratio AFTRG. At this time, larger values are calculated as air-fuel ratio feedback correction values FAFL and FAFR so that the air-fuel ratios AFL and AFR of the exhaust gas coincide with the target air-fuel ratio AFTRG through the air-fuel ratio feedback control. Therefore, the alcohol concentration learned values ALCGL and ALCGR are updated based on the actual alcohol concentrations CALCL and CALCR by updating the alcohol concentration learned values ALCGL and ALCGR based on the air-fuel ratio feedback correction values FAFL and FAFR. can do.

  Here, if the actual alcohol concentration is equal in the left and right banks 11 and 21, the learned values ALCGL and ALCGR of the alcohol concentration should be updated as the same value in the left and right banks 11 and 21, respectively. On the other hand, the air-fuel ratio sensors 66 and 67 have individual differences, and their output voltages VAFL and VAFR vary. Therefore, although the actual alcohol concentrations CALCL and CALCR are equal in the left and right banks 11 and 21, the output voltages VAFL and VAFR of the air-fuel ratio sensors 66 and 67 are different values in the left and right banks 11 and 21, respectively. As a result, the learned values ALCGL and ALCGR of the alcohol concentration are also updated as different values in the left and right banks 11 and 21.

  Therefore, in the present embodiment, the air fuel ratio sensors 66 and 67 are calculated by calculating the average value ALCGAVE (= (ALCGL + ALCGR) / 2) of the learning values ALCGL and ALCGR of the alcohol concentration updated for each of the left and right banks 11 and 21. Errors in the alcohol concentration learning values ALCGL and ALCGR caused by variations in the output voltages VAFL and VAFR are reduced. Further, the fuel injection amount is calculated based on the average value ALCGAVE of the alcohol concentration learning value thus calculated.

  However, in the configuration in which the fuel injection amount is calculated based on the average value ALCGAVE of each learned value of the alcohol concentration updated for each of the left and right banks 11 and 21, it is provided for each of the left and right banks 11 and 21. In the configuration in which the two fuel pipes 77 and 79 are connected in series, the following problem occurs. That is, during engine operation after refueling, the left bank 11 corresponding to the left fuel pipe 77 disposed upstream in the fuel supply system and the right bank 21 corresponding to the right fuel pipe 79 disposed downstream are actually The alcohol concentrations CALCL and CALCR of the slag are greatly different. Therefore, when the above-described alcohol concentration learning value update control is executed from this state, even if the actual alcohol concentrations CALCL and CALCR are equal in the left and right banks 11 and 21, the upstream side in the fuel supply system In the left bank 11, the alcohol concentration learning value ALCGL tends to deviate to a side larger than the actual alcohol concentration CALCL. In the downstream right bank 21, the alcohol concentration learning value ALCGR tends to deviate to a smaller side than the actual alcohol concentration CALCR. As a result, there arises a problem that it takes a long time to update the alcohol concentration learning values ALCGL and ALCGR to values corresponding to the actual alcohol concentrations CALCL and CALCR through the alcohol concentration learning value update control. .

  Therefore, in the present embodiment, the alcohol concentrations CALCL and CALCR contained in the fuel injected from the fuel injection valves 14a to 14d and 24a to 24d are supplied to the left and right banks 11 and 21 through the electronic control unit 50 during engine operation after refueling. Are determined to be equal. When it is determined that the alcohol concentration contained in the fuel injected from the fuel injection valves 14a to 14d and 24a to 24d is equal in the left and right banks 11 and 21, alcohol is used for both the left and right banks 11 and 21. The learning values ALCGL and ALCGR of the concentration are changed to the average value ALCGAVE (= (ALCGL + ALCGR) / 2) of the learning values ALCGL and ALCGR immediately before the alcohol concentration updated for each of the left and right banks 11 and 21. As a result, through the alcohol concentration learning value update control, the time required until the alcohol concentration learning values ALCGL and ALCGR are updated to values corresponding to the actual alcohol concentrations CALCL and CALCR is reduced.

  Next, the alcohol concentration learning value update control will be described in detail with reference to FIG. FIG. 3 is a flowchart showing a processing procedure of alcohol concentration learning value update control. The series of processes shown in this flowchart is executed only once by the electronic control unit 50 during engine operation.

  In this process, first, it is determined whether or not an execution condition for air-fuel ratio feedback control is satisfied (step S101). If it is determined that the execution condition of the air-fuel ratio feedback control is not satisfied (step S101: “NO”), the determination process is repeatedly executed until the execution condition is satisfied.

  On the other hand, if it is determined that the execution condition of the air-fuel ratio feedback control is satisfied as a result of the determination process in step S101 (S101: “YES”), then, through the air-fuel ratio feedback control, the air-fuel ratio feedback correction value is obtained. FAFL and FAFR are calculated for each of the left and right banks 11 and 21 (step S102). Then, the alcohol concentration learning values ALCGL and ALCGR are updated for each of the left and right banks 11 and 21 based on the air-fuel ratio feedback correction values FAFL and FAFR (step S103).

  When the learned values ALCGL and ALCGR of the alcohol concentration are updated in this way, it is next determined whether or not the elapsed period ΔT from the engine start is equal to or longer than the predetermined period ΔTth (S104). Here, the fuel injection valves 14a to 14d are used, for example, when a large amount of fuel is returned to the fuel tank through the high-pressure pressure regulator 82 and the first return path 80 among the fuel existing in the main path 76 and the fuel pipes 77 and 79. , 24a to 24d, the predetermined period ΔTth is set shorter as the time required for the alcohol concentrations CALCL and CALCR contained in the fuel injected from the left and right banks 11 and 21 to become equal.

  In the determination process of step S104, when it is determined that the elapsed period ΔT from the engine start is not longer than the predetermined period ΔTth (step S104: “NO”), the elapsed period ΔT from the engine start is equal to or longer than the predetermined period ΔTth. Until the determination is made, the processes in steps S102 to S104 are repeated.

  On the other hand, if it is determined in the determination process of step S104 that the elapsed period ΔT from the engine start is equal to or longer than the predetermined period ΔTth (step S104: “YES”), then both the left and right banks 11 and 21 are determined. The learning values ALCGL and ALCGR of the alcohol concentration are updated for each of the left and right banks 11 and 21 in the process of the previous step S103, and the average value ALCGAVE of the learning values ALCGL and ALCGR of the alcohol concentration (= (ALCGL + ALCGR) / 2) (Step S105). Then, this series of processing ends.

  Next, referring to the timing chart of FIG. 4, (a) transition of alcohol concentration CALCL contained in the fuel in the left bank 11 and (b) alcohol contained in the fuel in the right bank 21 during engine operation after refueling. Transition of concentration CALCR, (c) Transition of air-fuel ratio feedback correction value FAFL of left bank 11, (d) Transition of learned value ALCGL of alcohol concentration of left bank 11, (e) Air-fuel ratio feedback correction value FAFR of right bank 21 (F) Transition of the learned value ALCGL of the alcohol concentration in the right bank 21 and (g) Average value ALCGAVE (= (ALCGL + ALCGR) / 2) of the learned value of the alcohol concentration updated for each of the left and right banks 11 and 21 ). In the figure, the case where the concentration of alcohol contained in the fuel increases from “0%” to “X1%” before and after refueling is shown.

  As shown in the figure, after the timing t1 after the engine is started, the refueled new fuel reaches the left fuel pipe 77 so that the alcohol concentration CALCL contained in the fuel increases in the left bank 11. (FIG. 4A). On the other hand, since the right fuel pipe 79 is arranged downstream of the left fuel pipe 77 in the fuel supply system, new fuel that has been refueled has not yet reached the right fuel pipe 79, and in the right bank 21. For a while, the alcohol concentration CALCR remains “0%” and does not change (FIG. 4B).

  At this time, the learned values ALCGL and ALCGR of the alcohol concentration are not updated, and are based on the average value ALCGAVE (in this case, “0%”) of the learned values ALCGL and ALCGR of the alcohol concentration updated during the previous engine operation. Thus, the fuel injection amount is calculated. Therefore, in the 11 banks on the left side, the increase in the alcohol concentration CALCL is not taken into account, so the fuel becomes insufficient. As a result, the air-fuel ratio feedback correction value FAFL suddenly increases (FIG. 4C), and the alcohol concentration learning value ALCGL updated based on the air-fuel ratio feedback correction value FAFL increases rapidly. (FIG. 4D). On the other hand, in the right bank 21, the learned value ALCGR of the alcohol concentration is maintained at the previous value “0%” (FIG. 4 (f)). Therefore, the average value ALCGAVE (= (ALCGL + ALCGR) / 2) of the learning values of the alcohol concentration is calculated as a half value (= ALCGL / 2) of the learning value ALCGL of the alcohol concentration in the left bank 11 (FIG. 4 ( g)).

  Next, in the period up to the timing t2 when the alcohol concentration CALCL included in the fuel increases in the right bank 21, the alcohol concentration CALCR does not increase in the right bank 21 even though the alcohol concentration CALCR does not increase. The fuel injection amount is calculated based on the average value ALCGAVE of each learning value, that is, half the learning value ALCGL of the alcohol concentration in the left bank 11. Therefore, in the right bank 21, the fuel becomes excessive, and the air-fuel ratio feedback correction value FAFR suddenly decreases (FIG. 4 (e)). Here, the learned value ALCGR of the alcohol concentration that is updated based on the air-fuel ratio feedback correction value FAFR tends to rapidly decrease, but is “0%” that is the lower limit value of the learned value ALCGR of the alcohol concentration. Therefore, it does not actually decrease further (FIG. 4 (f)).

  On the other hand, in the left bank 11, since the average value ALCGAVE of each learned value of the alcohol concentration continues to be higher than the actual alcohol concentration CALCL after the timing t1, the fuel shortage state continues. As a result, the alcohol concentration learning value ALCGL increases prior to the increase in the actual alcohol concentration CALCL (FIGS. 4A and 4D).

  In the right bank 21, the alcohol concentration CALCR contained in the fuel increases after the timing t2 (FIG. 4 (a)), but for a while, it is injected with respect to the actual alcohol concentration CALCR. The state where the fuel becomes excessive continues, and the air-fuel ratio feedback correction value FAFR becomes lower than “0” (FIG. 4E). Therefore, the learning value ALCGR of the alcohol concentration is continuously maintained at “0%” (FIG. 4 (f)). After that, when the actual alcohol concentration CALCR in the right bank 21 further increases (FIG. 4B) and approaches the average value ALCGAVE of each learned value of alcohol concentration, the air-fuel ratio feedback correction value FAFR becomes smaller. It will increase. When the air-fuel ratio feedback correction value FAFR exceeds “0” after timing t3 (FIG. 4 (e)), the alcohol concentration learning value ALCGR increases with a delay from the actual increase of the alcohol concentration CALCR. (FIGS. 4B and 4F).

  Thus, in the left bank 11, the learned value ALLCGL of the alcohol concentration increases prior to the increase in the actual alcohol concentration CALCL, whereas in the right bank 21, the alcohol concentration of the alcohol concentration is delayed after the increase in the actual alcohol concentration CALCR. The learning value ALCGR will increase. Therefore, after that, when the actual alcohol concentrations CALCL and CALCR become equal in the left and right banks at timing t4, the learned value ALCGL of the alcohol concentration in the left bank deviates to the side larger than the actual alcohol concentration CALCR, and the right side The learning value ALCGR of the alcohol concentration in the bank is in a state of being deviated to a side smaller than the actual alcohol concentration.

  Here, in the present embodiment, at the timing t5 when the elapsed period ΔT from the engine start becomes the predetermined period ΔTth, the learning values ALCGL and ALCGR of the alcohol concentration for both the left and right banks 11 and 21 are changed to the left and right banks 11, The learning value ALCGL immediately before the alcohol concentration updated every 21 is changed to an average value ALCGAVE (= (ALCGL + ALCGR) / 2) of ALCGR. That is, in the left bank 11, the alcohol concentration learned value ALCGL is changed to be smaller than the value updated immediately before, and in the right bank 21, the alcohol concentration learned value ALCGR is larger than the value updated immediately before. To be changed. Through these things, the alcohol concentration learning values ALCGL and ALCGR are brought closer to the actual alcohol concentration CALCL (= X1), respectively.

According to the control apparatus for an internal combustion engine according to the present embodiment described above, the following effects can be obtained.
(1) Whether the alcohol concentration contained in the fuel injected from the fuel injection valves 14a to 14d and 24a to 24d is equal in the left and right banks 11 and 21 when the engine is operated after refueling through the electronic control unit 50. It was decided to judge. When it is determined that the alcohol concentration contained in the fuel injected from the fuel injection valves 14a to 14d and 24a to 24d is equal in the left and right banks 11 and 21, both the left and right banks 11 and 21 are determined. The learning values ALCGL and ALCGR of the alcohol concentration are changed to the average values of the learning values ALCGL and ALCGR immediately before the alcohol concentration updated for each of the left and right banks 11 and 21. Thus, even when there is a cumulative error in the alcohol concentration learning values ALCGL and ALCGR, the alcohol concentration learning values ALCGL and ALCGR can be brought close to the actual alcohol concentration CALCL and CALCR. Become. Accordingly, it is possible to reduce the time required for the alcohol concentration learning values ALCGL and ALCGR to be updated to values corresponding to the actual alcohol concentrations CALCL and CALCR through the alcohol concentration learning value update control.

  (2) The alcohol concentrations CALCL and CALCR contained in the fuel injected from the fuel injectors 14a to 14d and 24a to 24d when the elapsed period ΔT from the engine start after refueling is equal to or longer than the predetermined period ΔTth are the left and right banks 11. , 21 are determined to be equal. Further, the predetermined period ΔTth is variably set according to the engine operating state. As a result, the predetermined period ΔTth can be set accurately small. Accordingly, it is possible to further reduce the time required for the alcohol concentration learning values ALCGL and ALCGR to be updated to values corresponding to the actual alcohol concentrations CALCL and CALCR through the alcohol concentration learning value update control.

  Note that the control device for an internal combustion engine according to the present invention is not limited to the configuration exemplified in the above embodiment, and can be implemented as, for example, the following forms appropriately modified.

  In the above embodiment, it is used to determine whether or not the alcohol concentrations CALCL and CALCR contained in the fuel injected from the fuel injection valves 14a to 14d and 24a to 24d are equal in the left and right banks 11 and 21. The predetermined period ΔTth is set to be shorter as the amount of fuel returned to the fuel tank 71 through the high-pressure pressure regulator 82 and the first return path 80 increases. However, the parameter as the engine operating state for variably setting the predetermined period ΔTth is not limited to this, and in addition to or instead of this, an integrated value of the fuel injection amount after refueling is adopted. You can also In this case, the alcohol concentrations CALCL and CALCR contained in the fuel injected from the fuel injection valves 14a to 14d and 24a to 24d are increased in the left and right banks 11 and 21, as the integrated value of the fuel injection amount after refueling increases. Since the time required to be equal becomes shorter, the predetermined period ΔTth may be set shorter as the integrated value increases.

  As in the above-described embodiment, setting the predetermined period ΔTth variably according to the engine operating state means that the alcohol concentration learned values ALCGL and ALCGR are changed to the actual alcohol concentrations CALCL and CALCR through the alcohol concentration learning value update control. It is desirable to further reduce the time required for updating to a value in accordance with. However, the predetermined period ΔTth according to the present invention is not limited to the variable setting according to the engine operating state as described above, and the predetermined period ΔTth can be a fixed value regardless of the engine operating state.

  In the above embodiment, the alcohol concentrations CALCL and CALCR contained in the fuel injected from the fuel injectors 14a to 14d and 24a to 24d are changed to the left and right when the elapsed period ΔT from the engine start after refueling is equal to or longer than the predetermined period ΔTth. Are determined to be equal in the banks 11 and 21. However, the configuration for determining whether or not the alcohol concentrations CALCL and CALCR contained in the fuel injected from the fuel injection valves 14a to 14d and 24a to 24d are equal in the left and right banks 11 and 21 is limited to this. It is not something that can be done. In addition, for example, the fuel injection amount is injected from the fuel injection valve when the integrated value of the fuel injection amount from the engine start after refueling exceeds a predetermined value, or when the travel distance of the vehicle on which the engine 10 is mounted exceeds a predetermined distance. Alternatively, it may be determined that the alcohol concentration contained in the fuel is equal in the plurality of cylinder rows.

  In the above embodiment, the fuel injection amount is calculated based on the average value ALCGAVE of the learning values ALCGL and ALCGR of the alcohol concentration updated for each of the left and right banks 11 and 21, but the fuel injection amount However, the calculation mode is not limited to this. In short, if the fuel injection amount is calculated based on the value between the learned values ALCGL and ALCGR of the alcohol concentration updated for each of the left and right banks 11 and 21, the calculation mode of the fuel injection amount is appropriately changed. May be.

  In the above embodiment, when it is determined that the alcohol concentration contained in the fuel injected from the fuel injection valve is equal in the left and right banks 11 and 21, during engine operation after refueling, the left and right banks 11, 21 for each of the learning values ALCGL. ACLGR is changed to an average value ALCGAVE of the learning values ALCGL and ALCGR immediately before the alcohol concentration updated for each of the left and right banks 11 and 21. However, the change mode of the learning value through the learning value update control unit according to the present invention is not limited to this. In short, the learning values ALCGL and ALCGR of at least one alcohol concentration of the left and right banks 11 and 21 are changed so as to approach the average value ALCGAVE of each learning value immediately before the alcohol concentration updated for each of the left and right banks 11 and 21. Anything is acceptable.

  In the above embodiment, the engine 10 having a V-type cylinder arrangement in which the angle between the two banks 11 and 21 is smaller than 180 degrees is illustrated, but the internal combustion engine to be controlled by the control device according to the present invention is For example, a horizontally opposed internal combustion engine in which an angle between two cylinder rows is set to 180 degrees may be set as a control target. Further, an internal combustion engine in which the four cylinder rows are W-type cylinder arrangements can be controlled. In short, any internal combustion engine provided with air-fuel ratio detection means for detecting the air-fuel ratio of exhaust exhausted from the cylinders constituting the cylinder row for each cylinder row may be used.

1 is a schematic diagram schematically showing a schematic configuration of an engine and an electronic control device that controls the engine, according to an embodiment of a control device for an internal combustion engine according to the present invention. The schematic diagram which shows typically the schematic structure of the fuel supply system of the engine in this embodiment, and the electronic control apparatus which controls this. The flowchart which shows the process sequence of alcohol concentration learning value update control in the embodiment. The timing chart which shows transition of the various parameters at the time of engine operation after refueling of the embodiment. The timing chart which shows transition of the various parameters at the time of engine operation after the conventional refueling.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Left bank, 12a, 12b, 12c, 12d, 22a, 22b, 22c, 22d ... Cylinder, 13a, 13b, 13c, 13d, 23a, 23b, 23c, 23d ... Spark plug, 14a, 14b, 14c, 14d, 24a, 24b, 24c, 24d ... fuel injection valve, 21 ... right bank, 31, 32 ... intake manifold, 33 ... left intake passage, 34 ... right intake passage, 35 ... common intake passage, 36 ... throttle valve 37 ... throttle motor, 41, 42 ... exhaust manifold, 43 ... left exhaust passage, 44 ... right exhaust passage, 50 ... electronic control device (air-fuel ratio correction value calculating means, learning value updating means, determination means), 61 ... engine Rotational speed sensor, 62 ... Intake amount sensor, 63 ... Throttle opening sensor, 64 ... Accelerator opening sensor, 65 ... Water temperature sensor, 6 ... Left air-fuel ratio sensor (air-fuel ratio detection means), 67 ... Right air-fuel ratio sensor (air-fuel ratio detection means), 71 ... Fuel tank, 72 ... Fuel pump module, 73 ... Reservoir cup, 74 ... Feed pump, 74a ... Check Valve, 74b ... Fuel path, 75 ... Fuel filter, 75a ... Check valve, 76 ... Main path, 77 ... Left fuel pipe, 78 ... Fuel communication path, 79 ... Right fuel pipe, 80 ... First return path, 81 ... First 2 return path, 82 ... high pressure regulator, 83 ... low pressure regulator, 84 ... fuel pressure switching valve.

Claims (7)

A plurality of cylinder rows, a fuel injection valve provided for each cylinder constituting the cylinder row and supplying fuel to the cylinder, and an air-fuel ratio of exhaust discharged from the cylinder constituting the cylinder row for each cylinder row Applied to an internal combustion engine comprising an air-fuel ratio detecting means for detecting
An air-fuel ratio correction value calculating means for calculating an air-fuel ratio correction value of the fuel injection amount for each of the plurality of cylinder rows based on a deviation tendency between the air-fuel ratio of the exhaust detected by the air-fuel ratio detection means and the target air-fuel ratio;
Learning value updating means for updating the learning value of the alcohol concentration contained in the fuel injected from the fuel injection valve for each cylinder row based on the air-fuel ratio correction value calculated by the air-fuel ratio correction value calculating means; Prepared,
In a control device for an internal combustion engine that calculates a fuel injection amount based on a value between learning values of the alcohol concentration updated for each cylinder row by the learning value updating means,
Determination means for determining whether or not the alcohol concentration contained in the fuel injected from the fuel injection valve is equal in the plurality of cylinder rows;
The learning value update means, when it is determined that the alcohol concentration contained in the fuel injected from the fuel injection valve is equal in the plurality of cylinder rows by the determination means during engine operation after refueling, The learning value of the alcohol concentration of at least one of the plurality of cylinder rows is changed so as to approach the average value of the learning values immediately before the alcohol concentration updated for each cylinder row. Control device. The control apparatus for an internal combustion engine according to claim 1,
The learning value updating means changes the learning value of the alcohol concentration for both of the plurality of cylinder rows. The control apparatus for an internal combustion engine according to claim 1 or 2,
The learning value update means changes the learning value of the alcohol concentration for both of the plurality of cylinder rows to an average value of the learning values immediately before the alcohol concentration updated for each cylinder row. Control device for internal combustion engine. The control apparatus for an internal combustion engine according to any one of claims 1 to 3,
A control apparatus for an internal combustion engine, wherein a plurality of fuel pipes provided for each of the plurality of cylinder rows and respectively supplying fuel to the corresponding fuel injection valves are connected in series. The control apparatus for an internal combustion engine according to any one of claims 1 to 4,
The determination means determines that the alcohol concentration contained in the fuel injected from the fuel injection valve is equal in the plurality of cylinder rows when an elapsed period from engine start after refueling is a predetermined period or more. A control device for an internal combustion engine. The control apparatus for an internal combustion engine according to claim 5,
The control unit for an internal combustion engine, wherein the determination unit variably sets the predetermined period according to an engine operating state. The control device for an internal combustion engine according to any one of claims 1 to 6,
The control apparatus for an internal combustion engine, wherein the internal combustion engine includes two of the cylinder rows.

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