Injection control device

Abstract

To provide an injection control device capable of carrying out appropriate learning while suppressing the worsening of controllability.SOLUTION: An injection control device 1 in an embodiment includes a microcomputer 2 as an injection controller for controlling a fuel injection valve 3, which is current-driven by charge voltage obtained by boosting battery voltage (VB), to perform fuel injection a plurality of times for each cylinder. Then, the microcomputer 2 prohibits learning or adjusts the injection when the charge voltage does not reach a predetermined determination voltage.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an injection control device for controlling a fuel injection valve. [Background technology]

[0002] Multi-stage injection, in which fuel is injected multiple times into each cylinder, is used to reduce harmful components contained in exhaust gases. To maximize the effectiveness of reducing harmful components, each injection in the multi-stage injection must be performed with high precision. To achieve high-precision injection, it is necessary to learn the state of the fuel injection valve and charge it to the high voltage required for injection, as described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-113955 Summary of the Invention [Problem to be solved by the invention]

[0004] However, it is possible that the battery may not be charged to the high voltage required for injection depending on the operating environment, aging, vehicle driving conditions, etc. If the battery is not charged to the required high voltage, proper learning may not be possible, and the required injection amount may not be secured, resulting in poor controllability.

[0005] The present disclosure has been made in consideration of the above-mentioned circumstances, and its purpose is to provide an injection control device that can perform appropriate learning and suppress deterioration of controllability. [Means for solving the problem]

[0006] The injection control device (1) of the present disclosure includes an injection control unit (2) that controls a fuel injection valve (3) that is driven by a charging voltage obtained by boosting a battery voltage so that the fuel is injected multiple times for each cylinder. Detecting a boost time required for the charging voltage to reach a target voltage, calculating a boost capacity indicating the amount of energy stored in the capacitor per unit time using the boost time, and learning the boost capacity by storing the boost capacity; If the charging voltage does not reach the predetermined threshold voltage, Boosting capability Inhibit learning or adjust injection. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of an injection control device according to an embodiment. [Figure 2] Flowchart showing fuel injection main routine [Figure 3] FIG. 10 is a diagram showing an example of injection timing for each cylinder. [Figure 4] FIG. 10 is a diagram showing an example of the relationship between an injection command, a driving current, and a charging voltage during injection. [Figure 5] Flowchart showing the process of the injection control unit [Figure 6] A diagram showing an example of adjusting the injection command along with the relationship with the charging voltage. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment will be described with reference to the drawings. As shown in FIG. 1, an injection control device 1 of this embodiment is configured as an electronic control device including a microcomputer 2 having a CPU, various memories, etc. (not shown). This injection control device 1 controls fuel injection valves 3 provided in each cylinder of an internal combustion engine. Note that FIG. 1 illustrates an example of a fuel injection valve 3 provided in a four-cylinder internal combustion engine, with #1 representing the first cylinder, #2 representing the second cylinder, #3 representing the third cylinder, and #4 representing the fourth cylinder. As is well known, this fuel injection valve 3 has components such as a coil and a spring, and the electrical and mechanical characteristics of these components are involved in the state and behavior of the fuel injection valve 3, such as the valve opening and closing operations.

[0009] The injection control device 1 includes a microcomputer 2, a boost circuit 4, and a drive control circuit 5. The boost circuit 4 has a capacitor 6, and boosts the battery voltage (VB) by charging the capacitor 6, and supplies the boosted voltage to the drive control circuit 5 as a charging voltage (VCHG). The boost circuit 4 also includes a charging voltage detection unit 7 and an element temperature detection unit 8. The charging voltage detection unit 7 detects the charging voltage boosted by the boost circuit 4 and outputs it to the microcomputer 2. The element temperature detection unit 8 detects the temperatures of elements such as the capacitor 6 and an inductor (not shown) that configure the boost circuit 4, and outputs it to the microcomputer 2.

[0010] The drive control circuit 5 has a switching circuit configured with a transistor 9, and opens and closes the supply path of the charging voltage to the fuel injector 3 based on an injection command (TQ) which is a command value output from the microcomputer 2.

[0011] 2, the microcomputer 2 generates and outputs an injection command for each injection in each cylinder, thereby controlling the injection of fuel from the fuel injection valve 3. This microcomputer 2 corresponds to an injection control unit that controls the fuel injection valve 3, which is driven by a charging voltage obtained by boosting the battery voltage, so that fuel is injected multiple times in one cycle for each cylinder.

[0012] In step S1, the microcomputer 2 calculates the total injection amount of fuel to be injected from the fuel injection valve 3 of the target cylinder, the number of injections, the individual required injection amount for each injection, and the energization time. For example, the microcomputer 2 generates an injection command based on various parameters and outputs it to the drive control circuit 5. The parameters may include a crank signal (Ne) corresponding to the engine speed, a throttle opening signal corresponding to the throttle valve opening detected by a throttle opening sensor, vehicle information such as water temperature (THW), the fuel pressure detected by a fuel pressure sensor 10 and the fuel temperature detected by a fuel temperature sensor 11 provided in a fuel supply system that supplies fuel to the fuel injection valve 3, etc. However, the parameters exemplified here are merely examples.

[0013] Next, in step S2, the microcomputer 2 determines whether normal injection can be performed. In this embodiment, the microcomputer 2 determines that normal injection can be performed if the fuel pressure detected by the fuel pressure sensor 10 is lower than a predetermined pressure threshold and if past injections, including the previous injection, have been performed normally. This pressure threshold is set in advance as a determination value for determining whether the fuel pressure is excessively high or excessively high.

[0014] On the other hand, the microcomputer 2 determines that normal injection cannot be performed if the fuel pressure detected by the fuel pressure sensor 10 is higher than the pressure threshold value or if the previous injection was not performed normally. At this time, the microcomputer 2 determines that the previous injection was not performed normally if, for example, at least one of the following conditions continues for a predetermined time: the change in rotation speed during the combustion stroke is equal to or less than a predetermined value, the amount of fuel pressure drop caused by injection is equal to or less than a predetermined value, the valve closing timing after the end of current supply during injection is earlier than a predetermined timing, or the cranking time at the start of the internal combustion engine is equal to or more than a predetermined value.

[0015] If the microcomputer 2 determines that normal injection can be performed, the result in step S2 is YES, and therefore the microcomputer 2 sets a normal current conduction pattern in step S3. As the normal current conduction pattern, the value of the charging voltage to be applied to the fuel injector 3 and the peak value and hold value of the drive current that can achieve that charging voltage are set. Furthermore, the current conduction pattern is set appropriately to a value that allows normal injection to be performed while taking into account variations in the fuel injector 3 and the drive control circuit 5, etc.

[0016] On the other hand, if the microcomputer 2 determines that normal injection is not possible, the result in step S2 is NO, and therefore the microcomputer 2 sets a current conduction pattern for abnormal situations in step S6. For example, if the fuel pressure is equal to or greater than the pressure threshold, the force pressing the fuel injection valve 3 toward the valve closing side may become excessively large, resulting in abnormal injection. Therefore, the microcomputer 2 sets a current conduction pattern such that, for example, after the drive current has risen to a peak current after the start of current conduction, the charging voltage is repeatedly applied. The current conduction pattern for abnormal situations can be variably set according to, for example, the fuel pressure.

[0017] Once the energization pattern is set, the microcomputer 2 performs various corrections in step S4. In step S4, for example, the microcomputer 2 performs a process of correcting the valve-opening energy input when the fuel injector 3 opens as a result of starting to energize the fuel injector 3, a process of correcting the valve-closing timing based on the behavior of the fuel injector 3 when it closes, a static correction process of correcting variations in the mechanical characteristics of the fuel injector 3, and a battery voltage correction process of correcting variations in the injection amount due to a drop in battery voltage. However, the corrections shown here are merely examples.

[0018] Next, in step S5, the microcomputer 2 outputs an energization instruction as an energization command signal to the drive control circuit 5 based on the injection amount and energization time determined by appropriately performing the various corrections described above. Then, a drive signal is sent from the drive control circuit 5 to the fuel injector 3. For example, as shown in FIG. 3, it is assumed that injection is controlled in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder, and that fuel is injected five times during the intake stroke, compression stroke, combustion stroke, and exhaust stroke of each cylinder.

[0019] When an injection command is issued, the fuel injector 3 turns on the injection command, and the drive control circuit 5 applies a charging voltage to the fuel injector 3, causing the fuel to start injecting fuel. When the injection command is released, the fuel injector 3 turns off the injection command, stops applying the charging voltage, and stops injecting fuel. Note that, as will be described in detail later, HVCHG and Vstd are voltage values ​​set as determination voltages, with HVCHG corresponding to the target voltage and Vstd corresponding to the standard voltage. Also, "° CA" represents the crank angle.

[0020] The injection control device 1 of this embodiment, as an example, performs learning related to fuel injection. Therefore, the microcomputer 2 is provided with a boost time detection unit 12, a boost capacity calculation unit 13, a boost capacity storage unit 14, an injection time correction unit 15, and an injection time instruction unit 16 in order to learn the boost capacity and reflect the learning results. These are functional units realized by software by executing a program on the microcomputer 2. However, the learning target of the injection control device 1 is not limited to the boost capacity, and other items such as the state of the fuel injection valve 3 can also be learned.

[0021] The boost capacity is learned in the following manner: The boost time detection unit 12 detects the boost time required for the charging voltage to reach the target voltage based on the detection result of the charging voltage detection unit 7, and outputs the detected boost time to the boost capacity calculation unit 13. The boost capacity calculation unit 13 uses the boost time to calculate the boost capacity, which indicates the amount of energy stored in the capacitor 6 per unit time, and outputs the calculated capacity to the boost capacity storage unit 14 and the injection time correction unit 15.

[0022] The boost capacity storage unit 14 stores the input boost capacity, thereby enabling correction of the injection set time during a period when the boost capacity calculation unit 13 cannot calculate the boost capacity. That is, the boost capacity storage unit 14 learns the boost capacity at the time of fuel injection. The period when the boost capacity α cannot be calculated is a period when at least one of the following conditions holds: the capacitor 6 is discharging, or the charging voltage exceeds the battery voltage. The period can also be set to a period excluding the period from when the injection control device 1 is powered on until the fuel injection valve 3 starts injecting fuel.

[0023] The injection time correction unit 15 compares the calculated boost capacity with a predetermined reference boost capacity, sets an injection correction time, and outputs it to the injection time instruction unit 16. For example, if the boost capacity is higher than the reference boost capacity, the charging voltage will be higher than in the case of the reference boost capacity. In this case, the time required for the drive current that drives the fuel injector 3 to reach the valve opening threshold current required to open the valve will be shorter.

[0024] Therefore, the injection time correction unit 15 calculates an injection correction time that shortens the injection setting time so that the injection amount is the same as that in the case of the reference boost capacity. On the other hand, when the boost capacity is lower than the reference boost capacity, the injection time correction unit 15 calculates an injection correction time that lengthens the injection setting time so that the injection amount is the same as that in the case of the reference boost capacity, because the time it takes for the drive current to reach the valve-opening threshold current is longer.

[0025] The injection time instructing unit 16 generates an injection command for each cylinder based on the various parameters described above. At this time, the injection time instructing unit 16 corrects the injection time calculated based on the various parameters by the injection correction time calculated by the injection time correction unit 15 to generate an injection command and outputs it to the drive control circuit 5. Then, the drive control circuit 5 drives the fuel injector 3 by switching the transistor 9 based on the injection command.

[0026] The microcomputer 2 is also provided with a learning possibility determination unit 17 and an injection command adjustment unit 18. These are functional units realized by software when the microcomputer 2 executes a program.

[0027] Although the details will be described later, the learning possibility determination unit 17 determines whether learning is being performed in the injection control device 1 based on the charging voltage. In the present embodiment, whether learning is possible is determined by whether storage of the boost capacity is permitted or prohibited. However, the learning possibility determination unit 17 is not limited to learning the boost capacity, and can be configured to determine whether learning is possible for other items, such as the state of the fuel injection valve 3.

[0028] Furthermore, as will be described in detail later, the injection command adjustment unit 18 adjusts the injection command generated by the injection time instruction unit 16 for each injection of each cylinder. In this embodiment, the injection command adjustment unit 18 adjusts the injection command by delaying the timing of issuing the injection command, extending the injection time, and limiting the number of injections. Whether or not to adjust the injection command is determined based on the charging voltage.

[0029] Next, the operation of the above-described configuration will be described. As mentioned above, to maximize the effect of reducing harmful components contained in exhaust gases, each injection in the multi-stage injection needs to be performed with high precision. In this case, it is necessary to learn the state of the fuel injection valve 3 and to charge it to the high voltage required for injection. However, depending on the operating environment, aging, vehicle driving conditions, etc., it is possible that it may not be possible to charge it to the high voltage required for injection.

[0030] If the battery is not charged to the required high voltage, there is a risk that appropriate learning cannot be performed. Furthermore, if correction is made based on an inappropriate learning result, fuel injection cannot be performed appropriately. Furthermore, if the battery is not charged to the required high voltage, the required injection amount cannot be secured, and controllability may deteriorate. Therefore, the injection control device 1 is configured to perform appropriate learning and to suppress deterioration of controllability.

[0031] First, definitions of terms will be explained. As shown in FIG. 4, the injection command (TQ) is a signal that can be switched between on and off. Hereinafter, the timing when the injection command switches from off to on will be referred to as TQ=ON, and the timing when the injection command switches from on to off will be referred to as TQ=OFF. At this time, the drive current (INJ_A) of the fuel injector 3 increases when the injection command is turned on, and the fuel injector 3 performs a valve opening operation to start fuel injection. On the other hand, the drive current decreases when the injection command is turned off, and the fuel injector 3 performs a valve closing operation to stop fuel injection.

[0032] The charging voltage (VCHG) decreases when the injection command is turned on and increases after the injection command is turned off. In this embodiment, the target voltage (HVCHG) and the standard voltage (Vstd) are set as determination voltages for determining whether learning is possible and whether adjustment of the injection command is necessary. Even if the charging voltage has not reached the target voltage, it is possible to perform appropriate injection by adjusting the injection command, and it is considered that an appropriate learning result can be obtained. On the other hand, if the charging voltage is clearly insufficient, it is possible that appropriate injection cannot be performed even if the injection command is adjusted, and therefore learning should not be performed. For this reason, the injection control device 1 sets the target voltage and the standard voltage separately.

[0033] Furthermore, in the injection control device 1, V1 and V2 are set as timings for acquiring the charging voltage to determine whether learning is possible and whether adjustment of the injection command is necessary. V1 is the timing for acquiring the charging voltage before an injection command is issued, and is set as a predetermined timing when the injection command is off. This V1 timing can be changed as appropriate depending on the vehicle state, such as for each cylinder, each injection, or the engine speed. V2 is the timing for acquiring the charging voltage when an injection command is issued, and is set as a predetermined timing after TQ=ON. Hereinafter, the charging voltage acquired at the timing V1 will be referred to as VCHG_V1, and the charging voltage acquired at the timing V2 will be referred to as VCHG_V2.

[0034] The microcomputer 2 executes the process shown in Fig. 5 as a specific injection control mode in this embodiment. In this embodiment, the microcomputer 2 executes the process shown in Fig. 5 as so-called crank angle synchronous process synchronized with a crank angle signal output when the crank rotates at a predetermined crank angle, for example, 30° CA. Therefore, when the crank angle signal is input in step S11, the microcomputer 2 starts the actual process. This crank signal is input to the microcomputer 2 as, for example, an interrupt signal.

[0035] When the process starts, the microcomputer 2 acquires the target cylinder number in step S12, and determines the injection amount (Q) and the number of injections (N) for each cylinder in step S13. Hereinafter, the number of injections determined in step S13 will be referred to as the planned number of injections.

[0036] Next, the microcomputer 2 acquires VCHG_V1 in step S14, and determines whether VCHG_V1≧HVCHG in step S15. In step S15, the microcomputer 2 determines whether the charging voltage (VCHG) at V1 during the third injection, for example, has reached the target voltage (HVCHG), as shown as injection adjustment example 1 in FIG. 6. In the case of injection adjustment example 1, VCHG_V1≧HVCHG during the third injection, and the charging voltage has been sufficiently boosted to enable normal injection. Note that the numbers in parentheses following the injection commands in FIG. 6 indicate the number of injections for each cylinder.

[0037] If the microcomputer 2 determines that HG_V1≧HVCHG, the result in step S15 is YES, and therefore the microcomputer 2 turns on the injection command (TQ) to issue an injection instruction in step S16. Note that the actual injection instruction is issued at a predetermined timing set after V1.

[0038] When an injection command is issued, the microcomputer 2 acquires the charging voltage (VCHG_V2) at V2 in step S17, and determines whether VCHG_V2≧Vstd in step S18. As shown in FIG. 4 above, the charging voltage decreases when the injection command is turned on. If the charging voltage is lower than the standard voltage (Vstd) at this time, there is a risk of a malfunction such as not being able to inject the planned injection amount in that injection.

[0039] Therefore, the microcomputer 2 determines whether VCHG_V2≧Vstd. In the case of injection adjustment example 1, VCHG_V2≧Vstd at the third injection, and the charging voltage is sufficient. Also, unless a sudden circuit failure or the like occurs, if VCHG_V1≧HVCHG, VCHG_V2 acquired after TQ=ON is basically considered to be VCHG_V2≧Vstd.

[0040] In this case, it is considered that the charging voltage has been boosted to a level at which appropriate injection can be performed. Therefore, the microcomputer 2 permits learning in step S19. In other words, the microcomputer 2 determines that the current injection will be performed normally and permits learning so that the learning results can be used for the next and subsequent injections. In other words, if VCHG_V1≧HVCHG and VCHG_V2≧Vstd, the microcomputer 2 determines that learning is necessary and permits learning.

[0041] Next, the microcomputer 2 decrements the number of injections by 1 in step S20, and determines whether N>0 in step S21. For example, if this is the third injection, the microcomputer 2 determines YES in step S21 because the remaining number of injections is 2 and N>0, and proceeds to step S14 to repeat the same processing for the next injection. On the other hand, if N=0 after repeated injections, the microcomputer 2 determines NO in step S20 and terminates the processing. In this way, if VCHG_V1≧HVCHG and VCHG_V2≧Vstd, normal injection will be performed.

[0042] Incidentally, as shown in injection adjustment example 2 in Figure 6, a situation may be assumed in which VCHG_V1 does not reach HVCHG, for example, during the third injection. In this case, since VCHG_V1 is not equal to or greater than HVCHG, the microcomputer 2 determines NO in step S15 and delays the timing of TQ=ON by, for example, Δt in step S22. This Δt can be set to a fixed value, or can be made variable according to various parameters.

[0043] Next, the microcomputer 2 proceeds to step S17 to acquire VCHG_V2, and determines whether VCHG_V2≧Vstd in step S18. In the case of injection adjustment example 2, since VCHG_V2≧Vstd, the microcomputer 2 permits learning in step S19 and executes the processes of steps S20 and S21 as described above. In other words, even if VCHG_V1≧HVCHG is not true, the microcomputer 2 permits learning if the charging voltage when the injection command was issued has reached the standard voltage.

[0044] In this injection adjustment example 2, for example, in the next fourth injection, VCHG_V1≧HVCHG and VCHG_V2≧Vstd. Therefore, the microcomputer 2 determines that learning is necessary for the fourth injection and allows learning. In other words, the microcomputer 2 temporarily delays the timing of TQ=ON in the third injection, but cancels the injection adjustment if the charging voltage becomes equal to or higher than the standard voltage in the subsequent injection.

[0045] 6 as an injection adjustment example 3, a situation may also be assumed in which, for example, VCHG_V1 does not reach HVCHG in the third injection, and VCHG_V2 does not reach VStd when the timing of TQ=ON is delayed. In this case, the microcomputer 2 determines NO in step S18, and therefore determines in step S23 whether the scheduled number of injections is possible within the remaining time given until the scheduled number of injections is completed.

[0046] If the microcomputer 2 determines that the scheduled number of injections is possible, the result in step S23 is YES, and therefore in step S24, learning is prohibited and the injection end timing is delayed. In step S24, since VCHG_V1≧HVCHG and VCHG_V2≧VStd are not satisfied, it is determined that the injection state is not normal, and learning is prohibited. This prohibits storage of, for example, boost capacity related to the current injection, and prevents learned values ​​acquired in an abnormal state from being reflected in the next and subsequent injections.

[0047] Furthermore, in step S24, as shown in the third injection adjustment example, the timing of TQ=OFF is delayed, and the injection time from TQ=ON to TQ=OFF is extended by Δp. This Δp is set to a time that can ensure the determined injection amount. In other words, by extending the injection time, the microcomputer 2 ensures that the injection amount determined for this injection can be ensured even if the charging voltage is insufficient.

[0048] Next, in step S25, the microcomputer 2 determines whether the injection amount can be secured by extending the injection time. In this case, the microcomputer 2 may be configured to perform the determination of whether the injection amount can be secured multiple times until the injection end time. If the microcomputer 2 determines that the injection amount can be secured, the result of step S25 becomes YES, and the microcomputer 2 proceeds directly to step S20.

[0049] In the third example of injection adjustment, for example, in the fourth injection, VCHG_V1≧HVCHG and VCHG_V2≧Vstd. Therefore, the microcomputer 2 cancels the prohibition of learning and also cancels the injection adjustment. On the other hand, if the microcomputer 2 determines that the injection amount cannot be secured, the result in step S25 is NO, so that the microcomputer 2 determines that an abnormality has occurred in step S27, notifies other control devices of this fact, and then proceeds to step S20. This allows a fail-safe function, such as limiting the output of the internal combustion engine, to be activated.

[0050] 6 as an injection adjustment example 4, a situation may also be assumed in which, for example, VCHG_V1 does not reach HVCHG in the third injection, and VCHG_V2 does not reach VStd when the timing of TQ=ON is delayed. In this case, the microcomputer 2 determines NO in step S18, and therefore determines in step S23 whether the planned number of injections is possible in the remaining time.

[0051] If the microcomputer 2 determines that the planned number of injections is not possible, the result in step S23 is NO, and therefore the microcomputer 2 decrements the number of injections by 1 and distributes the remaining injection amount in step S26. In other words, the microcomputer 2 limits the number of injections for each cylinder by making it less than the planned number of injections, and distributes the injection amount to be injected for each cylinder to the next injection and thereafter. As a result, even if the number of injections is limited, the total injection amount required for the next injection and thereafter can be injected.

[0052] Next, the microcomputer 2 proceeds to step S24 to prohibit learning and delay the injection end timing, and then, if the injection amount can be secured in step S25, proceeds to step S20 to decrement the number of injections by 1. As a result, if this is the third injection, for example, the number of injections is decremented by 1 in step S26, and the number of injections is further decremented by 1 in step S20, so that N = 3 - 1 - 1 = 1. The microcomputer 2 then proceeds to step S14 to similarly perform processing based on the charging voltage for the next injection.

[0053] In this way, in the injection control device 1, if the charging voltage when driving the fuel injector 3 does not reach the predetermined determination voltage, the learning is prohibited or a process for adjusting the injection is executed.

[0054] According to the injection control device 1 described above, the following effects can be obtained. The injection control device 1 includes a microcomputer 2 as an injection control unit that controls a fuel injector 3, which is driven by a charging voltage obtained by boosting a battery voltage (VB), to perform multiple fuel injections for each cylinder. If the charging voltage does not reach a predetermined determination voltage, the microcomputer 2 prohibits learning or adjusts injection.

[0055] To maximize the effectiveness of reducing harmful components contained in exhaust gas, it is necessary to learn the state of the fuel injector 3 and charge it to the high voltage required for injection. However, if the injector is not charged to the required high voltage, proper learning cannot be performed, and if such learning results are reflected in the next injection or later, fuel injection will not be performed properly. Furthermore, if the injector is not charged to the required high voltage, the required injection amount cannot be secured, which may result in poor controllability.

[0056] Therefore, if the charging voltage does not reach a predetermined judgment voltage, the injection control device 1 prohibits learning or adjusts injection, thereby enabling appropriate learning and preventing deterioration of controllability.

[0057] The injection control unit sets a standard voltage and a target voltage as judgment voltages, and if the charging voltage when an injection instruction is given is less than the standard voltage, or if the charging voltage at a specified voltage detection timing does not reach the target voltage, it prohibits learning or adjusts injection.

[0058] When the charging voltage is sufficiently boosted, learning can be performed appropriately. Furthermore, even if the charging voltage is somewhat low, if appropriate injection can be achieved by adjusting the injection, appropriate learning can be performed by including that injection as a learning target. Therefore, appropriate learning results can be obtained and the learning frequency can be prevented from being excessively reduced. Furthermore, since learning should not be performed when the charging voltage is clearly insufficient, prohibiting learning in such a situation can prevent problems such as the next or subsequent injection being corrected based on inappropriate learning results. In other words, appropriate learning can be performed by separately setting the target voltage and the standard voltage.

[0059] The injection control unit sets a standard voltage and a target voltage as the judgment voltages, and prohibits learning if the charging voltage when an injection command is issued is less than the standard voltage or if the target voltage has not been reached at a predetermined voltage detection timing, and permits learning if the charging voltage is equal to or greater than the standard voltage. As a result, by separately setting the target voltage and the standard voltage as described above, appropriate learning can be performed, and even if learning is once prohibited, learning can be performed if the charging voltage is such that appropriate learning results can be obtained at the next or subsequent injections, preventing the learning frequency from being excessively reduced.

[0060] The injection control unit sets a standard voltage and a target voltage as the reference voltage, adjusts injection if the charging voltage when an injection command is issued is less than the standard voltage, or if the target voltage has not been reached at a predetermined voltage detection timing, and cancels the injection adjustment if the charging voltage is equal to or greater than the standard voltage. This makes it possible to adjust the timing of TQ=ON if the target voltage has not been reached, or adjust the number of injections or injection time if the standard voltage has not been reached, allowing for more precise injection adjustment. Furthermore, even if injection adjustment has been made once, unnecessary adjustments can be prevented from being made at subsequent injections.

[0061] The injection control unit adjusts the injection by extending the injection time to ensure the planned injection amount, thereby enabling the planned injection amount of fuel to be injected even when the charging voltage is insufficient, and preventing deterioration of controllability.

[0062] The injection control unit adjusts the injection by reducing the number of injections from the scheduled number of injections. At this time, by distributing the injection amount required for the next and subsequent injections as described above, the scheduled injection amount of fuel can be injected, and deterioration of controllability can be suppressed.

[0063] The injection control unit adjusts the injection by delaying the timing of issuing an injection command. This means that delaying the timing of issuing an injection command means that the time required to increase the charging voltage is extended. As a result, the charging voltage has risen by the time the injection command is issued, so it can be expected that the engine will be in a state where appropriate injection can be performed. If appropriate injection can be performed, deterioration of controllability can be suppressed.

[0064] Furthermore, when adjusting injection, appropriate adjustments can be made depending on the state of the charging voltage by combining extending the injection time to ensure the planned injection amount, as in the embodiment, extending the injection time to ensure the planned injection amount, and delaying the timing of issuing the injection command.

[0065] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. [Explanation of symbols]

[0066] In the drawing, 1 is an injection control device, 2 is a microcomputer (injection control section), and 3 is a fuel injection valve.

Claims

1. An injection control unit (2) controls a fuel injection valve (3) that is driven by a current using a charging voltage obtained by boosting a battery voltage by charging a capacitor (6) so that the fuel is injected multiple times for each cylinder, The injection control unit Detects the boost time required for the charging voltage to reach the target voltage, Using the voltage boost time, a voltage boost capacity indicating the amount of energy stored in the capacitor per unit time is calculated; The calculated boost capacity is stored to learn the boost capacity; The injection control device prohibits learning of the boosting capability or adjusts the injection when the charging voltage does not reach a predetermined judgment voltage.

2. 2. The injection control device according to claim 1, wherein the injection control unit sets a standard voltage and a target voltage as the judgment voltage, and prohibits learning or adjusts injection if the charging voltage when an injection instruction is issued is lower than the standard voltage, or if the charging voltage at a predetermined voltage detection timing has not reached the target voltage.

3. 3. The injection control device according to claim 1, wherein the injection control unit sets a standard voltage and a target voltage as the judgment voltage, and prohibits learning when the charging voltage when an injection instruction is issued is lower than the standard voltage, or when the charging voltage at a predetermined voltage detection timing has not reached the target voltage, and allows learning when the charging voltage is equal to or higher than the standard voltage.

4. 3. The injection control device according to claim 1, wherein the injection control unit sets a standard voltage and the target voltage as the judgment voltage, adjusts the injection when the charging voltage when an injection instruction is issued is lower than the standard voltage, or when the charging voltage at a predetermined voltage detection timing has not reached the target voltage, and cancels the injection adjustment when the charging voltage reaches the target voltage.

5. The injection control device according to claim 4, wherein the injection control unit adjusts the injection by extending the injection time to ensure a planned injection amount.

6. The injection control device according to claim 4, wherein the injection control unit adjusts the injection by reducing the number of injections from a scheduled number of injections.

7. The injection control device according to claim 4, wherein the injection control unit adjusts the injection by delaying the timing of issuing an injection command.

8. The injection control unit Comparing the boosting capacity with a predetermined reference boosting capacity; When the boosting capacity is higher than the reference boosting capacity, an injection correction time is calculated to shorten the injection setting time so that the injection amount becomes the same as that in the case of the reference boosting capacity; When the boosting capacity is lower than the reference boosting capacity, an injection correction time is calculated so that the injection setting time is lengthened to obtain the same injection amount as in the case of the reference boosting capacity; 2. The injection control device according to claim 1, wherein the fuel injection time is corrected by an injection correction time to generate an injection command and output the injection command to the fuel injection valve.

9. An injection control device as described in claim 1, wherein the injection control unit is configured not to calculate the boost capacity during a period when at least one of the following conditions is true: the capacitor is discharging, or the charging voltage exceeds the battery voltage.

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