JP2009293552A - Injection control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection control device for an internal combustion engine, improving correction accuracy. <P>SOLUTION: This injection control device for the internal combustion engine is appropriately used for controlling injection quantity based on a correction map with a relation between an interval in multi-stage injection and the amount of correction for the injection quantity defined. Specifically, by changing the interval in the multi-stage injection, an interval with command injection quantity matched to the actual injection quantity is calculated, the calculated interval is determined as a reference interval, and an interval with the amount of correction made to be zero in the correction map is determined as a correction interval. A ratio between the reference interval and the correction interval is determined as an interval correction gain, and the interval is corrected by the interval correction gain to determine the amount of correction in the correction map. Thereby, it is possible to suppress a cycle delay in waviness correction and to improve accuracy of the amount of correction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection control device for an internal combustion engine that controls an injection amount.

  In an internal combustion engine in which multi-stage injection is performed, there is a tendency that a deviation occurs between the command injection amount and the actual injection amount (actual measurement value) depending on the interval. Therefore, for example, Patent Documents 1 to 3 describe techniques for suppressing such a shift. Patent Document 1 describes a technique for intentionally shifting the interval time to obtain a deviation time at which the injection amount deviation becomes 0, and calculating a correction amount according to the deviation time. Patent Document 2 describes a technique for correcting an injection amount by calculating a deviation amount between a stored reference variation pattern and the variation pattern. Patent Document 3 describes a technique for calculating a correction amount using a correction interval time in which a reference fluctuation pattern corresponding to a reference rail pressure is corrected according to the rail pressure. In addition, a technique related to the present invention is described in Patent Document 4.

JP 2007-132334 A JP-A-2005-76561 JP 2006-214402 A JP 2003-314337 A

  However, even when the corrections described in Patent Documents 1 to 4 are performed, there is a difference between the command injection amount and the actual injection amount due to the influence of the injection amount change, individual variation, fuel properties, and the like. May remain.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an injection control device for an internal combustion engine that can improve the accuracy of correction.

  In one aspect of the present invention, an injection control device for an internal combustion engine that controls an injection amount based on a correction map that defines a relationship between an interval in a multi-stage injection and a correction amount for the injection amount changes the interval in the multi-stage injection. By calculating, an interval in which the command injection amount and the actual injection amount coincide with each other, reference interval determination means for determining the calculated interval as a reference interval, and a correction amount corresponding to the reference interval in the correction map Correction interval determining means for determining an interval for which the value is 0 as a correction interval, interval correction gain determining means for determining a ratio between the reference interval and the correction interval as an interval correction gain, and an interval as the interval correction gain. To fix And a correction amount determining means for determining a correction amount in serial correction map.

  The above-described injection control device for an internal combustion engine is suitably used for controlling the injection amount based on a correction map that defines the relationship between the interval and the correction amount of the injection amount in multistage injection. Specifically, the reference interval determining means calculates an interval in which the command injection amount and the actual injection amount coincide with each other by changing the interval in the multistage injection, and determines the calculated interval as the reference interval. The correction interval determining means determines an interval corresponding to the reference interval and having a correction amount of 0 in the correction map as a correction interval. The interval correction gain determining means determines a ratio between the reference interval and the correction interval as an interval correction gain. The correction amount determining means determines the correction amount in the correction map by correcting the interval with the interval correction gain. By doing in this way, the shift | offset | difference of the period in waviness correction | amendment can be suppressed, and the precision improvement of a correction amount can be aimed at.

  In another aspect of the injection control apparatus for an internal combustion engine, the correction interval determining means corrects an interval in which the correction amount in the correction map is 0 with a pulsation period, and the corrected interval is corrected with the correction. It is determined as an interval. As a result, the correction amount in the correction map can be accurately calculated regardless of changes in the propagation speed of the pressure pulsation and the length of the high-pressure passage.

  In another aspect of the injection control apparatus for an internal combustion engine, the correction amount determination means corrects the phase in the correction map based on the interval correction gain. This also makes it possible to improve the accuracy of the injection amount.

  In another aspect of the above-described injection control device for an internal combustion engine, the correction amount determination means performs minute injection amount learning at an interval such that the deviation amount between the command injection amount and the actual injection amount becomes a peak, The amplitude in the correction map is further corrected. Thereby, it is possible to perform correction in accordance with the actual fluctuation amount of the injection amount, and it is possible to further improve the accuracy of the injection amount.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Device configuration]
FIG. 1 is a block diagram showing a schematic configuration of an internal combustion engine 100 to which an injection quantity learning device for an internal combustion engine according to the present embodiment is applied. In FIG. 1, solid arrows indicate intake and exhaust flows, and broken arrows indicate signal input / output.

  The internal combustion engine 100 is mounted on a vehicle and uses the output of the engine body 10 configured as an in-line four-cylinder engine as a driving power source. The engine body 10 is composed of, for example, a diesel engine. Each cylinder of the engine body 10 is connected to an intake manifold 11 and an exhaust manifold 12. The engine body 10 includes a fuel injection valve 15 provided in each cylinder, and a common rail 14 that supplies high-pressure fuel to each fuel injection valve 15, and fuel is supplied to the common rail 14 by a fuel pump (not shown). Supplied in state. The fuel injection amount and injection timing from the fuel injection valve 15 are controlled by a control signal S15 supplied from the ECU 7.

  An intake passage 20 connected to the intake manifold 11 has an air flow meter (AFM) 21 that detects the amount of intake air supplied to the engine body 10, a throttle valve 22a that adjusts the intake air amount, and a turbocharger that supercharges intake air. 23, a compressor 23a, an intercooler (IC) 24 for cooling the intake air, and a throttle valve 22b for adjusting the intake air amount are provided. On the other hand, an exhaust passage 25 connected to the exhaust manifold 12 is provided with a turbine 23b of a turbocharger 23 that is rotated by the energy of exhaust gas, and a catalyst 30 that can purify the exhaust gas.

  The internal combustion engine 100 is configured to recirculate exhaust gas from the upstream side of the turbine 23b to the downstream side of the compressor 23a. Specifically, the exhaust gas is recirculated by the EGR passage 31 that connects the upstream position of the turbine 23 b in the exhaust passage 25 and the downstream position of the intercooler 24 in the intake passage 20. An EGR valve 33 for controlling the amount of EGR gas is provided on the EGR passage 31.

  The internal combustion engine 100 is provided with various sensors. Specifically, the engine body 10 is provided with a rotation fluctuation sensor 42. The rotation fluctuation sensor 42 detects a fluctuation in the rotation speed of the engine body 10 and supplies a detection signal S42 corresponding to the detected rotation fluctuation to the ECU 7. The internal combustion engine 100 is provided with various sensors in addition to the above-described sensors, but description of portions not particularly related to the present embodiment will be omitted.

  Each element of the internal combustion engine 100 is controlled by an ECU (Engine Control Unit) 7. The ECU 7 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). In the present embodiment, the ECU 7 functions as an injection amount control device for an internal combustion engine in the present invention, and a map (hereinafter referred to as “correction map”) that defines the relationship between the interval and the correction amount of the injection amount in the multistage injection. Based on this, the injection amount is controlled. Although details will be described later, the ECU 7 operates as a reference interval determination unit, a correction interval determination unit, and a correction amount determination unit. The ECU 7 also controls other components in the internal combustion engine 100, but a description of portions that are not particularly related to the present embodiment is omitted.

  Further, the present invention is not limited to the application to the in-line four-cylinder internal combustion engine 100, but also to an internal combustion engine having a number of cylinders other than four cylinders or an internal combustion engine in which the cylinders are arranged in a V shape. Can be applied. Further, the present invention is not limited to the application to the internal combustion engine 100 configured by the direct injection type fuel injection valve 15, and may be applied to the internal combustion engine configured by the port injection type fuel injection valve. Can do.

[First embodiment]
Next, a first embodiment of the present invention will be described.

  When multi-stage injection (for example, fuel injection including pilot injection and main injection) is executed, the interval between the command injection amount (hereinafter also simply referred to as “command value”) and the actual injection amount (actual measurement value) is determined according to the interval. There is a tendency for deviation to occur. In order to suppress the influence of such a deviation, a relationship between the interval and the amount (correction amount) for correcting the injection amount is obtained in advance, and the injection amount correction (hereinafter also referred to as “swell correction”) based on the relationship. )).

  FIG. 2 shows an example of a correction map that defines the relationship between the interval and the correction amount in multistage injection. That is, the map used when performing swell correction is shown. In FIG. 2, the horizontal axis indicates the interval, and the vertical axis indicates the correction amount. The interval shown on the horizontal axis is made dimensionless by rail pressure, temperature, and the like. That is, the correction map is made dimensionless by rail pressure, temperature, etc., and is made into one map.

  As shown in FIG. 2, in the correction map, it can be seen that the correction amount varies (swells) according to the interval. The correction map is created by measuring and analyzing the injection amount characteristic in advance. For example, it is created by measuring the injection amount fluctuation amount in the fuel injection valve 15 when various intervals are changed. Further, the correction map can be appropriately corrected according to the detected temperature, rail pressure, and the like.

  Even when the swell correction is performed based on the correction map as described above, a deviation may remain between the command injection amount and the actual injection amount. FIG. 3 shows an example of the deviation that can occur after the swell correction. FIG. 3 shows the relationship between the interval and the deviation from the command value (deviation between the command injection amount and the actual injection amount). Specifically, FIG. 3A shows a graph before waviness correction, and FIG. 3B shows a graph after waviness correction. As shown in FIG. 3 (b), it can be seen that when waviness correction is performed, a large deviation is corrected as compared with the case where waviness correction is not performed, but the deviation from the command value is completely corrected. You can see that it has not been done. Although it is conceivable to correct the correction map in order to eliminate such a shift, it can be said that it is actually difficult to correct the correction map so that the shift is completely eliminated. This is because deviation from the command value may be caused by individual variations, fuel properties, and the like, and it is difficult to appropriately detect such individual variations, fuel properties, and the like.

  This will be described in detail with reference to FIG. In FIG. 4, the horizontal axis represents the interval, and the vertical axis represents the deviation from the command value.

  FIG. 4A shows an example of a result when ideal waviness correction is performed. A graph C1 shows the amount of deviation of the injection amount before correction, and a graph C2 shows a correction map used for swell correction. Graph C3 shows the result of correcting the undulation using the correction map shown by graph C2 for the shift amount shown by graph C1. From the graph C3, it can be seen that the waviness correction is appropriately performed by the correction map, that is, there is almost no deviation from the command value. In this case, it can be said that the command injection amount and the actual injection amount coincide with each other regardless of which interval is used.

  On the other hand, FIG. 4B shows an example of an actual result in the swell correction. A graph D1 shows a deviation amount of the injection amount before correction, and a graph D2 shows a correction map used for swell correction. Further, the graph D3 shows the result of correcting the undulation using the correction map shown by the graph D2 for the shift amount shown by the graph D1. From the graph D3, it can be seen that the deviation from the command value remains even after the waviness correction. This is presumably because the amplitude and the period of the correction map shown by the graph D2 are slightly shifted from the graph D1. In this case, the difference between the command injection amount and the actual injection amount tends to vary depending on the interval.

  Ideally, it is desirable that the waviness correction as shown in FIG. However, in practice, it can be said that it is difficult to perform the swell correction as shown in FIG. 4A due to individual variations, fuel properties, correction map accuracy, and the like. That is, in reality, there is a tendency to perform swell correction as shown in FIG. 4B, and it can be said that it is difficult to completely eliminate the deviation from the command value.

  Therefore, in the first embodiment, the ECU 7 calculates the correction amount from the correction map after correcting the interval when calculating the correction amount in order to suppress the shift of the period in the swell correction. Specifically, first, the ECU 7 calculates an interval in which the command injection amount and the actual injection amount coincide with each other by changing the interval in the multistage injection, and determines the calculated interval as a reference interval. An interval corresponding to the reference interval and having a correction amount of 0 in the correction map is determined as a correction interval. Then, the ECU 7 determines the ratio between the reference interval and the correction interval as the interval correction gain, and corrects the interval with the interval correction gain to determine the correction amount in the correction map. Thereby, the shift | offset | difference of the period in waviness correction | amendment can be suppressed, and the precision improvement of a correction amount can be aimed at.

  First, a reference interval determination method will be described in detail with reference to FIGS. 5 and 6.

FIG. 5 shows a time chart of the control performed when determining the reference interval. Specifically, in order from the top, the rotational speed of the engine body 10, the multistage injection interval, and the learning injection flag are shown. In the present embodiment, the ECU 7 performs learning by single injection (for example, 2 mm ³ / st) and then performs multistage injection (for example, 2 mm ³ / st pilot) when the small injection amount learning is possible by single injection. Learning with injection and 2 mm ³ / st main injection) is executed. More specifically, when the ECU 7 performs multi-stage injection at the time of deceleration and executes the minute injection amount learning, the time interval becomes constant according to the rotational speed of the engine body 10 as indicated by the broken line area A1. Command interval. For example, the ECU 7 sets the interval from “Aint (° C. A) = rotational speed (rpm) × 360/60/1000 × 360 × Tint0 (ms)”. “Tint0” in the equation corresponds to the reference interval. As a result, even if the rotational speed changes, fuel is injected with an accurate injection amount, so that the actual injection amount can be accurately obtained from the torque fluctuation. That is, it is possible to suppress fluctuations in the injection amount due to rotational fluctuations. The ECU 7 executes the multi-stage injection a plurality of times, estimates the torque (torque fluctuation) from the rotation fluctuation obtained from the rotation fluctuation sensor 42, obtains the actual injection quantity from the estimated torque, and obtains the actual injection quantity. Learning is performed using the average value of.

Further, as indicated by the broken line area A2, the ECU 7 gradually changes the interval in the multi-stage injection (that is, changes it stepwise) in order to detect an interval in which the command injection amount and the actual injection amount coincide. For example, the ECU 7 sets the interval obtained from “Tint0 [i + 1] = Tint0 [i] + ΔTint” to gradually change the interval. “ΔTint” in the equation corresponds to an introductory variable. And ECU7 calculates | requires the interval in which instruction | command injection amount and actual injection amount correspond by changing an interval gradually in this way, and determines the said interval as a reference | standard interval. For example, the ECU 7 determines the interval when the estimated torque is equivalent to 4 mm ⁴ / st as the reference interval.

  FIG. 6 is a diagram for explaining an example of a reference interval calculation method. In FIG. 6, the horizontal axis indicates the interval, and the vertical axis indicates the deviation from the command value.

  In FIG. 6A, a graph B1 shows the actual injection amount deviation amount, and a graph B2 shows a correction map. Although a correction map is shown in the figure, the waviness correction is not performed when calculating the reference interval.

  First, the ECU 7 sets a point B3 at which the correction amount becomes 0 in the correction map (that is, a point where the command injection amount and the actual injection amount match in the correction map) to the reference interval initial value Tint0 [0]. The reference interval initial value Tint0 [0] corresponds to, for example, the previously determined reference interval. Next, the ECU 7 executes multi-stage injection at the time of deceleration and obtains the actual injection amount Qv [0] from the rotation fluctuation as described above, thereby obtaining the difference ΔQv [0] between the command injection amount and the actual injection amount. calculate. Then, the ECU 7 increases the interval by ΔTint when ΔQv [0] is positive, and shortens the interval by ΔTint when ΔQv [0] is negative. The deviation ΔQv [1] from the quantity is calculated again. In the example shown in FIG. 6A, since ΔQv [0] is positive, the ECU 7 uses, as an interval, Tint0 [1] obtained by adding ΔTint to the reference interval initial value Tint0 [0], and ΔQv [1 ] Is calculated. Thereafter, the ECU 7 changes the intervals in the order of Tint0 [1] → Tint0 [2] → Tint0 [3], and the difference ΔQv [2], ΔQv [3] between the command injection amount and the actual injection amount in each interval. ] Are calculated sequentially. In this case, the difference between the command injection amount and the actual injection amount crosses zero between Tint0 [2] and Tint0 [3]. That is, positive and negative are reversed at the deviations ΔQv [2] and ΔQv [3] between the command injection amount and the actual injection amount.

  FIG. 6B shows the vicinity of the intervals Tint0 [2] and Tint0 [3] in FIG. 6A in an enlarged manner. In this case, since the difference between the command injection amount and the actual injection amount is between 0 and Tint0 [2] and Tint0 [3], the command injection is between Tint0 [2] and Tint0 [3]. It is considered that there is an interval in which the difference between the amount and the actual injection amount is zero. That is, it is considered that there is a reference interval Tint0 to be obtained between Tint0 [2] and Tint0 [3]. In FIG. 6B, the point B4 corresponds to the reference interval Tint0. Therefore, the ECU 7 calculates the reference interval Tint0 based on the results obtained from Tint0 [2] and Tint0 [3]. Specifically, the ECU 7 proportionally distributes Tint0 [2] and Tint0 [3] based on the deviations ΔQv [2] and ΔQv [3] between the command injection amount and the actual injection amount, thereby setting the reference interval Tint0. calculate. For example, the ECU 7 calculates the reference interval Tint0 based on the following formula (1).

Tint0 = − (ΔQv [2] · ΔTint0) / (ΔQv [3] −ΔQv [2])
+ ΔTint0 [2] Equation (1)
If the deviation ΔQv between the command injection amount and the actual injection amount obtained when the interval is changed by ΔTint is approximately 0, the ECU 7 does not perform the proportional distribution as described above, and The interval when ΔQv is obtained is determined as the reference interval as it is.

  Next, a method for determining the correction interval will be specifically described with reference to FIG. FIG. 7 shows an example of a correction map that defines the relationship between the interval and the correction amount in multistage injection. The ECU 7 calculates a correction interval using the correction map shown in FIG. First, when calculating the reference interval, the ECU 7 calculates, from the correction map, a corresponding dimensionless interval Th corresponding to the previously calculated reference interval with a correction amount of 0. For example, in the example of FIG. 6A, the point B3 corresponds to a corresponding dimensionless interval.

  By the way, when pilot injection and main injection are performed as multistage injection, when main injection is performed, pressure pulsation generated during pilot injection reciprocates between the common rail 14 and the fuel injection valve 15. As a result, the main injection amount and the main injection timing fluctuate at a predetermined cycle (pulsation cycle). Therefore, in the first embodiment, instead of using the corresponding dimensionless interval as the correction interval as it is, the correction interval is calculated in consideration of the influence of the pulsation period from the corresponding dimensionless interval. When it is considered that the influence of the pulsation period is small, the corresponding dimensionless interval may be used as the correction interval as it is.

  First, the pulsation cycle τ is calculated by the following equation (2).

Pulsation cycle τ = 4L ÷ Pressure pulsation propagation velocity Formula (2)
Note that L indicates the length of the high-pressure passage, and specifically indicates the distance from the opening end on the common rail 14 side of the high-pressure pipe (not shown) connected to the common rail 14 to the injection port of the fuel injection valve 15. ing. The propagation speed of pressure pulsation is calculated by the following equation (3).

Pressure pulsation propagation velocity = √ (bulk elastic modulus of fuel ÷ fuel density) Equation (3)
Here, the bulk modulus of fuel is a function of fuel pressure and fuel temperature, and the fuel density is a function of fuel temperature. The ECU 7 can calculate the fuel temperature and the fuel pressure based on various sensors of the internal combustion engine 100. Specifically, the ECU 7 calculates the fuel temperature and the fuel pressure based on a pressure sensor (not shown) and a fuel temperature sensor (not shown) attached to the common rail 14.

  The ECU 7 calculates the pulsation period τ using the above equations (2) and (3), and then determines a value obtained by multiplying the corresponding dimensionless interval Th by the pulsation period τ as a correction interval. Therefore, the correction interval is calculated by the following equation (4).

Correction interval = corresponding dimensionless interval Th × pulsation period τ Formula (4)
Next, the ECU 7 calculates an interval correction gain based on the reference interval and the correction interval calculated as described above. The interval correction gain is calculated, for example, by dividing the reference interval by the correction interval as shown in the following equation (5).

Interval correction gain = reference interval / correction interval (5)
When determining the correction amount, the ECU 7 corrects the interval with the interval correction gain and determines the correction amount in the correction map. Specifically, for example, when the interval correction gain is calculated by Expression (5), the ECU 7 determines a value obtained by dividing the interval by the interval correction gain as an interval in the correction map, and corresponds to the determined interval. The correction amount to be determined is determined from the correction map. Thereby, the shift | offset | difference of the period in waviness correction | amendment can be suppressed. Further, since the interval correction gain calculated by the above formulas (2) to (5) is calculated in consideration of the influence of the pulsation cycle, the propagation speed of the pressure pulsation and the high-pressure passage length are Regardless of the change, the correction amount in the correction map can be calculated with high accuracy.

  According to the first embodiment described above, it is possible to suppress the shift of the period in the swell correction, and it is possible to improve the accuracy of the correction amount.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment described above in that the phase of the correction map used for waviness correction is corrected and the amplitude is further corrected. This will be specifically described below.

  First, a method for correcting the phase of the correction map will be described. In the second embodiment, the ECU 7 corrects the phase based on the interval correction gain. Specifically, the ECU 7 corrects the dimensionless interval in the correction map with the interval correction gain so as to correspond to the actual interval. In this way, the correction map after the phase is corrected is used as a new correction map.

  FIG. 8 shows an example of the correction map after the phase is corrected. In FIG. 8, the horizontal axis indicates the interval, and the vertical axis indicates the deviation from the command value. A graph E1 shows the deviation amount of the injection amount (deviation amount before correction), and a graph E2 shows a correction map after the phase is corrected. Further, the graph E3 shows the result of correcting the undulation using the correction map shown by the graph E2 for the shift amount shown by the graph E1. From the graph E3, it can be seen that the deviation from the command value is largely corrected by the swell correction. Specifically, although there is a slight shift in the amplitude direction, it can be seen that undulation correction in phase is performed.

  By using the correction map whose phase is corrected in this way, the accuracy of the injection amount can be improved.

  Here, the control process of the ECU 7 in the case of correcting the phase in the above-described correction map will be specifically described with reference to the flowchart shown in FIG.

  In step S101, the ECU 7 calculates the accelerator opening and the engine speed based on the accelerator opening sensor and the rotation fluctuation sensor. In the subsequent step S102, the ECU 7 determines whether the engine is operating (accelerator opening and engine speed). ) To calculate the pilot injection amount and the main injection amount.

  In step S <b> 103, the ECU 7 calculates a target fuel pressure for realizing an optimal fuel injection pressure according to the operating state of the internal combustion engine 100. In subsequent step S104, the ECU 7 obtains an injection interval between the pilot injection and the main injection. This injection interval is a time interval from the end of pilot injection to the start of main injection.

  In step S105, the ECU 7 calculates the fuel temperature and the fuel pressure based on various sensors of the internal combustion engine 100. In subsequent step S106, the ECU 7 calculates the pulsation period and the interval correction gain using the equations (1) to (5) described in the first embodiment.

  In step S107, the ECU 7 calculates a dimensionless interval by dividing the injection interval calculated in step S104 by the pulsation period and the interval correction gain using the following equation (6).

Dimensionless interval =
Injection interval / (Pulsation cycle x Interval correction gain) (6)
In step S108, the ECU 7 calculates the correction amount for the dimensionless interval calculated in step S107 using the correction map. Specifically, as the correction map, a correction map for calculating the correction amount for the main injection amount and a correction map for calculating the correction amount for the main injection timing are created and stored in the memory of the ECU 7 respectively. By performing the processing of steps 107 and 108, the time base of the correction map based on the interval correction gain is corrected. In subsequent step S109, the final main injection amount and the main injection timing are determined by adding the correction amounts obtained in step S108 to the main injection amount and the main injection timing, respectively. Thereafter, the ECU 7 ends this control process.

  Thus, in the second embodiment, the phase is corrected by correcting the time axis of the correction map based on the interval correction gain. Thereby, it becomes possible to improve the accuracy of the injection amount.

  Next, a method for correcting the amplitude of the correction map will be described. In the second embodiment, the ECU 7 further corrects the amplitude with respect to the correction map whose phase has been corrected as described above. Specifically, the ECU 7 further corrects the amplitude by performing the minute injection amount learning at an interval such that the deviation amount between the command injection amount and the actual injection amount peaks in the correction map in which the phase is corrected.

  In one example, the ECU 7 measures the deviation amount at the peak value in a state in which the swell correction is reflected. That is, the correction map is corrected based on the actual injection amount obtained when the swell correction is performed. Specifically, the ECU 7 obtains a correction map in which the amplitude is corrected by correcting the gain of the correction amount so that the estimated torque becomes the target value. In another example, the ECU 7 measures the deviation amount at the peak value without reflecting the swell correction. That is, the correction map is corrected based on the actual injection amount obtained with the swell correction cut. Specifically, the ECU 7 uses the ratio between the measured actual injection amount and the correction amount in the correction map as a gain correction coefficient, and uses the gain correction coefficient as the correction amount in the original correction map (correction map whose phase is corrected). By multiplying, a correction map with corrected amplitude is obtained. According to this, the time to reach the correction amount to be set can be shortened, that is, the learning repetition cycle can be reduced.

  FIG. 10 shows an example of a correction map after correcting the phase and amplitude. The graph F1 shows the amount of deviation of the injection amount (deviation amount before correction), the graph F2 shows the correction map after correcting the phase (corresponding to the graph E2 shown in FIG. 8), and the graph F3 Shows the correction map after correcting the phase and amplitude. The graph F4 shows the result of correcting the undulation using the correction map shown by the graph F3 for the shift amount shown by the graph F1. It can be seen from the graph F4 that the deviation from the command value is largely corrected by the swell correction. Specifically, when compared with the graph E3 shown in FIG. 8, it can be seen that there is almost no deviation from the command value. That is, it can be seen that not only the phase but also the swell correction with matching amplitude is performed.

  As described above, by correcting the correction map for both the phase and the amplitude, it is possible to perform the swell correction in accordance with the actual fluctuation amount of the injection amount. Therefore, it is possible to further improve the accuracy of the injection amount.

1 is a block diagram illustrating a schematic configuration of an internal combustion engine according to the present embodiment. It is a figure which shows an example of a correction map. An example of the deviation that can occur after waviness correction is shown. It is a figure for demonstrating the reason for cutting waviness correction. The time chart of the control performed when determining a reference | standard interval is shown. It is a figure for demonstrating an example of the calculation method of a reference | standard interval. It is a figure which shows an example of a correction map. An example of the correction map after correcting the phase is shown. It is a flowchart which shows the control processing which concerns on 2nd Example. An example of the correction map after correcting a phase and an amplitude is shown.

Explanation of symbols

7 ECU
DESCRIPTION OF SYMBOLS 10 Engine main body 14 Common rail 15 Fuel injection valve 20 Intake passage 23 Turbocharger 25 Exhaust passage 42 Rotation fluctuation sensor 100 Internal combustion engine

Claims (4)

An injection control device for an internal combustion engine that controls an injection amount based on a correction map that defines a relationship between an interval in a multi-stage injection and a correction amount of an injection amount,
By changing an interval in the multi-stage injection, an interval in which the command injection amount and the actual injection amount coincide with each other is calculated, and a reference interval determination unit that determines the calculated interval as a reference interval;
Correction interval determination means for determining an interval corresponding to the reference interval and having a correction amount of 0 in the correction map as a correction interval;
Interval correction gain determining means for determining a ratio between the reference interval and the correction interval as an interval correction gain;
An injection control device for an internal combustion engine, comprising: correction amount determination means for correcting an interval with the interval correction gain and determining a correction amount in the correction map.   The correction interval determining means corrects an interval corresponding to the reference interval and having a correction amount of 0 in the correction map with a pulsation period, and determines the corrected interval as the correction interval. 2. An injection control device for an internal combustion engine according to 1.   The injection control device for an internal combustion engine according to claim 1 or 2, wherein the correction amount determination means corrects a phase in the correction map based on the interval correction gain.   The correction amount determination unit further corrects the amplitude in the correction map by performing minute injection amount learning at an interval such that a deviation amount between the command injection amount and the actual injection amount reaches a peak. An injection control device for an internal combustion engine according to any one of the preceding claims.

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