JP2018123695A - Fuel injection control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain drive start timing of an injector from being shifted from timing of a requested injection position.SOLUTION: In a fuel injection control device, a drive start part starts the drive of an injector when a set start time comes. A setting processing part is started every time a crankshaft rotates by a prescribed angle, calculates a time T1 until a crank position reaches a requested injection position RA when this-time start is the one immediately before the start of the requested injection position RA, and sets a start time of the drive start part so that the drive start part is started when the time T1 elapses. Further, the setting processing part also sets a start time of a resetting part so that the resetting part is started at a time t2 which is earlier than the set start time t1 of the drive start part by a prescribed time α. When the resetting part is started, the resetting part calculates a time T2 until the crank position reaches the required injection position RA, and resets the start time of the drive start part so that the drive start part is started when the time T2 elapses.SELECTED DRAWING: Figure 7

Description

  The present disclosure relates to a fuel injection control device.

  For example, as described in Patent Document 1, in an apparatus that controls fuel injection to an engine, it is known to inject fuel at a target crank position. The crank position here is the rotational position of the crankshaft, which is a so-called crank angle.

JP 2005-273665 A

For example, the following can be considered as a specific configuration for controlling fuel injection by a microcomputer (hereinafter referred to as a microcomputer).
For example, the microcomputer calculates the crank position at which the drive of the injector is to be started as the required injection position by, for example, time synchronization processing at regular intervals. Starting driving of the injector corresponds to starting fuel injection from the injector to the engine.

  Then, in the crank synchronization process that is started every time the crankshaft rotates by a predetermined angle, the microcomputer starts the function of the injector (hereinafter referred to as drive) if the current start is the start immediately before the required injection position. A setting process for setting the start time of the start unit) is performed. In the setting process, the time until the crank position reaches the required injection position is calculated based on the current rotation speed of the crankshaft (that is, the engine rotation speed), and the drive start unit is activated when that time elapses. Thus, the activation time of the drive start unit is set.

  The drive start unit is activated when the activation time set by the setting process arrives, and starts driving the injector. Then, fuel injection from the injector to the engine is started.

  In such a configuration, when the engine decelerates after the start time of the drive start unit is set by the crank synchronization process, the actual timing of the required injection position, that is, the set start time, that is, The actual timing at which the crank position becomes the required injection position is later. For this reason, fuel injection from the injector is started at a crank position before the required injection position.

  Therefore, the present disclosure provides a technique capable of suppressing the drive start timing of the injector from deviating from the timing of the required injection position due to engine deceleration in the fuel injection control device.

  The fuel injection control device of the present disclosure includes a calculation unit (11, S105), a drive start unit (11, S310), a setting processing unit (11, S110 to S240), and a resetting unit (11, S510 to S550). And comprising.

The calculation unit calculates the crank position of the engine at which the drive of the injector (5) for injecting fuel into the engine is to be started as the required injection position.
The drive start unit is activated when the set activation time arrives and starts driving the injector.

  The setting processing unit is activated every time the crankshaft of the engine rotates by a predetermined angle. Then, when the current activation is the activation immediately before the required injection position calculated by the calculation unit, the setting processing unit determines the time until the crank position becomes the required injection position based on the current rotation speed of the crankshaft. And the activation time of the drive start unit is set so that the drive start unit is activated when the time has elapsed.

  Further, when the current activation of the setting processing unit is the activation immediately before the requested injection position, the setting processing unit sets a time that is a predetermined time before the activation time of the drive start unit set by the setting processing unit. Then, the activation time of the resetting unit is set so that the resetting unit is activated.

  When the resetting unit is activated, it performs resetting processing for resetting the activation time of the drive starting unit. In the resetting process, based on the current rotation speed of the crankshaft, the time until the crank position reaches the required injection position is calculated, and the drive start unit is started so that the drive start unit is activated when the time has elapsed. The start time of the part is reset.

  According to such a configuration, after the start time of the drive start unit is set by the setting processing unit, the engine decelerates, and the actual timing of the requested injection position with respect to the set start time of the drive start unit Even if the operation is delayed, the activation time of the drive start unit is reset by the resetting unit. Therefore, it can suppress that the drive start timing of an injector shifts | deviates from the timing of a request | requirement injection position by deceleration of an engine.

  In addition, the code | symbol in the parenthesis described in this column and a claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this indication is shown. It is not limited.

It is a block diagram which shows the structure of the electronic control apparatus of an embodiment. It is a flowchart showing a time synchronous process. It is a flowchart showing a crank synchronous process. It is a flowchart showing an energization ON process. It is a flowchart showing an electricity supply OFF process. It is a flowchart showing a delay trigger event process. It is explanatory drawing explaining the example of an effect | action of embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. Constitution]
As shown in FIG. 1, a crank angle sensor (hereinafter referred to as a rotation sensor) 3 and an injector 5 are connected to an electronic control device (hereinafter referred to as an ECU 1) as a fuel injection control device of the embodiment. Although not shown, a cam sensor is also connected to the ECU 1. ECU is an abbreviation for “Electronic Control Unit”.

  The rotation sensor 3 outputs a pulse signal every time it detects a plurality of teeth 9a formed at predetermined intervals around the rotor 9 that rotates together with the crankshaft 7 of the engine. Further, around the rotor 9, a portion (hereinafter referred to as a missing tooth portion) in which a predetermined number of tooth portions 9 a are continuously missing is provided. For this reason, in the signal from the rotation sensor 3, a portion (hereinafter referred to as a missing tooth signal portion) in which the generation interval of the pulse signal is a predetermined number times that of the generation interval of the other pulse signals occurs. The current crank position can be determined from the missing tooth signal portion and the signal from the cam sensor. In the present embodiment, the engine is mounted on a vehicle.

  The injector 5 is energized by the ECU 1 to inject fuel into the engine. Energizing the injector 5 corresponds to driving the injector 5. The injector 5 is provided for each cylinder of the engine. Here, the injector 5 of one cylinder will be described.

  The ECU 1 includes a microcomputer 11 as a control unit that performs various processes for controlling the engine. The microcomputer 11 includes a CPU 13 that executes a program and a semiconductor memory (hereinafter referred to as a memory) 15 such as a RAM, a ROM, and a flash memory.

  Various processes performed by the microcomputer 11 are realized by the CPU 13 executing a program stored in a non-transitional tangible recording medium. In this example, the memory 15 corresponds to a non-transitional tangible recording medium that stores a program. Also, by executing this program, a method corresponding to the program is executed. The number of microcomputers constituting the ECU 1 may be one or plural. Further, some or all of the functions of the microcomputer 11 may be realized using one or a plurality of hardware. For example, when part or all of the functions of the microcomputer 11 are realized by an electronic circuit that is hardware, the electronic circuit may be realized by a digital circuit including a large number of logic circuits, an analog circuit, or a combination thereof. good.

  Further, the ECU 1 includes an input circuit 17 that shapes the pulse signal from the rotation sensor 3 and inputs the pulse signal to the microcomputer 11, and an output circuit 19 that energizes the injector 5 in accordance with a command from the microcomputer 11. A pulse signal input from the rotation sensor 3 to the microcomputer 11 via the input circuit 17 is hereinafter referred to as a crank signal.

  In the present embodiment, the rotation sensor 3 outputs a pulse signal every time the crankshaft 7 rotates 10 ° (that is, every 10 ° CA). For this reason, as shown in the first stage of FIG. 7, the crank signal input to the microcomputer 11 is a rectangular wave in which a rising edge occurs every 10 ° CA. Here, the description is made excluding the aforementioned missing tooth signal portion. On the other hand, “CA” is a symbol meaning that the numerical value described before it is the rotation angle of the crankshaft 7. In FIG. 7, BTDC means before TDC. TDC is an abbreviation for “Top Dead Center”, that is, top dead center. For example, BTDC 90 ° CA is a crank position that is 90 ° before TDC.

[2. processing]
Next, the process which the microcomputer 11 performs for fuel injection control is demonstrated using the flowchart of FIGS.

[2-1. Time synchronization processing]
The microcomputer 11 executes the time synchronization process shown in FIG. 2 at regular intervals.
As shown in FIG. 2, when the time synchronization process is started, the microcomputer 11 acquires control information for controlling the engine in S100. The control information includes, for example, engine rotation speed, intake air amount, accelerator pedal operation amount by a vehicle driver, vehicle speed, and the like. The engine rotation speed is the rotation speed of the crankshaft 7. Note that the microcomputer 11 sequentially measures, for example, the time interval of the rising edge of the crank signal (that is, the time corresponding to 10 ° CA), and calculates the latest engine speed based on the time interval.

  In the next step S105, the microcomputer 11 determines the crank position at which the drive of the injector 5 is to be started, that is, the crank position at which fuel injection from the injector 5 is to be started, based on the control information acquired at S100. Calculated as RA. Further, in S105, the microcomputer 11 calculates the fuel injection amount from the injector 5 and calculates the drive time TQ of the injector 5 based on the fuel injection amount. Then, the microcomputer 11 thereafter ends the time synchronization process.

[2-2. Crank synchronization processing, energization on processing, energization off processing]
The microcomputer 11 executes the crank synchronization process of FIG. 3 every time the crankshaft 7 rotates by a predetermined angle. The predetermined angle is 30 ° in the present embodiment. Further, in the present embodiment, as shown in the first stage of FIG. 7, one of the timings every 10 ° CA where the rising edge occurs in the crank signal is the TDC timing. Then, the crank synchronization process is executed at the timing of every 30 ° CA including the timing of TDC among the timing at which the rising edge occurs in the crank signal. That is, the crank synchronization process is executed every 30 ° CA including TDC in synchronization with the rotation of the crankshaft 7. Note that these angle values are examples. Moreover, the microcomputer 11 grasps the current crank position based on the crank signal.

  As shown in FIG. 3, when the microcomputer 11 starts the crank synchronization process, in S110, the current start of the crank synchronization process is the start immediately before the requested injection position RA calculated in the time synchronization process (hereinafter, referred to as “the crank synchronization process”). It is determined whether or not the activation is performed immediately before injection). Specifically, it is determined whether or not the current crank position is the crank position one before the required injection position RA among the crank positions for every 30 ° CA where the crank synchronization process is to be started. .

  If the affirmative determination is made in S110, that is, if the current activation of the crank synchronization process is an activation immediately before injection, the microcomputer 11 proceeds to S120 and turns off the energization determination flag. The energization determination flag is a flag indicating whether energization of the injector 5 has been performed. The off state of the energization determination flag indicates that energization of the injector 5 has not been performed.

  In the next S130, the microcomputer 11 calculates a time T1 from the current time to the timing of the required injection position RA, that is, a time T1 from the current time until the crank position becomes the required injection position RA based on the current engine speed. To do. The timing of the required injection position RA is the timing at which the crank position becomes the required injection position RA. Specifically, the microcomputer 11 calculates the time T1 from the current time to the timing of the required injection position RA by dividing the difference in crank angle from the current crank position to the required injection position RA by the current engine speed. To do.

  In step S135, the microcomputer 11 determines whether the time T1 calculated in step S130 is equal to or longer than the predetermined time Tc. That is, it is determined whether or not there is a certain time Tc or more from the current time to the timing of the required injection position RA.

If the affirmative determination is made in S135, the microcomputer 11 proceeds to S140 and sets the energization on time.
The energization on time is the activation time of the energization on process shown in FIG. 4 for energizing the injector 5. In the present embodiment, the microcomputer 11 includes an energization on time setting unit in which time until the energization on time is set as information indicating the energization on time. The energization on time setting unit is configured by, for example, a register or a RAM. Then, in the microcomputer 11, the energization-on process of FIG. 4 is started when the time has elapsed since the time was set in the energization-on-time setting unit. The activation of the energization on process means that the microcomputer 11 starts executing the energization on process. That is, the time when the set time has elapsed after the time is set in the energization on time setting unit is the activation time of the energization on process. Therefore, setting a desired time in the energization on time setting unit corresponds to setting the activation time of the energization on process (that is, the energization on time).

  For this reason, in S140, the microcomputer 11 performs a process of setting the time T1 calculated in S130 in the energization on time setting unit as a process of setting the energization on time. In addition, the time itself is set in the power-on time setting unit, and the power-on process may be started when the time arrives. In this case, the microcomputer 11 may set the time obtained by adding the time T1 to the current time in the energization on time setting unit in S140.

  On the other hand, when the set time elapses after the time is set in the energization on time setting unit, the microcomputer 11 starts the energization on process of FIG. Note that the crank synchronization process of FIG. 3 has already been completed when the energization-on process is started.

  As shown in FIG. 4, the microcomputer 11 starts energizing the injector 5 in S310 when energization-on processing is started. In next S320, the energization off time is set, and then the energization on process is terminated.

  The energization off time is a start time of the energization off process shown in FIG. 5 for ending energization of the injector 5. In the present embodiment, the microcomputer 11 includes an energization off time setting unit in which time until the energization off time is set as information indicating the energization off time. The energization off time setting unit is configured by, for example, a register or a RAM. Then, in the microcomputer 11, when the time has elapsed after the time is set in the power-off time setting unit, the power-off process in FIG. 5 is started. The activation of the power-off process means that the microcomputer 11 starts executing the power-off process. That is, the time when the set time has elapsed after the time is set in the power-off time setting unit is the start time of the power-off process. Therefore, setting a desired time in the energization-off time setting unit corresponds to setting the activation time of the energization-off process (that is, the energization-off time).

  Therefore, in S320 of FIG. 4, the microcomputer 11 performs a process of setting the drive time TQ of the injector 5 calculated by the time synchronization process in the energization off time setting unit as a process of setting the energization off time. In addition, the time itself is set in the power-off time setting unit, and the power-off process may be started when the time arrives. In this case, in S320, the microcomputer 11 may set a time obtained by adding the driving time TQ to the current time in the energization off time setting unit.

Further, when the set time has elapsed since the time was set in the power-off time setting unit, the microcomputer 11 starts the power-off process in FIG.
As shown in FIG. 5, when the microcomputer 11 starts the energization-off process, the microcomputer 11 ends the energization to the injector 5 in S410, and then ends the energization-off process. Therefore, the time during which the injector 5 is energized is the drive time TQ calculated by the time synchronization process.

  Returning to the description of FIG. After performing the process of S140, the microcomputer 11 variably sets the predetermined time α used for setting the delay trigger time in accordance with the engine speed in S150. The delay trigger time is the start time of the delay trigger event process shown in FIG.

  The predetermined time α is information indicating how much time is before the energization on time set in S140. The microcomputer 11 sets the predetermined time α to a longer time as the engine speed increases, for example, based on a predetermined data map or calculation formula. Further, the predetermined time α is shorter than the time T1 set in the energization on time setting unit in S140.

In step S160, the microcomputer 11 sets a delay trigger time, and then ends the crank synchronization process.
In the present embodiment, the microcomputer 11 includes a delay trigger time setting unit in which time until the delay trigger time is set as information indicating the delay trigger time. The delay trigger time setting unit is configured by, for example, a register or a RAM. The microcomputer 11 starts the delay trigger event process of FIG. 6 when the time has elapsed since the time was set in the delay trigger time setting unit. The activation of the delay trigger event process means that the microcomputer 11 starts executing the delay trigger event process. That is, the time at which the set time has elapsed after the time is set in the delay trigger time setting unit is the start time of the delay trigger event process. Therefore, setting a desired time in the delay trigger time setting unit corresponds to setting the start time of the delay trigger event process (that is, the delay trigger time).

  In step S160, the microcomputer 11 sets a delay trigger time as a process for setting the delay trigger time by using a delay time Td shorter than the time T1 set in the energization on time setting unit in step S140 by a predetermined time α, that is, “T1-α”. Performs processing for setting in the time setting section. The time itself may be set in the delay trigger time setting unit, and the delay trigger event process may be activated when the time arrives. In this case, in S160, the microcomputer 11 may set the time obtained by adding “T1-α” to the current time in the delay trigger time setting unit.

  When the time set in the delay trigger time setting unit has elapsed after the processing of S160, the microcomputer 11 starts the delay trigger event processing of FIG. The contents of the delay trigger event process will be described later.

  On the other hand, if the microcomputer 11 makes a negative determination in S135, the microcomputer 11 proceeds to S170, and performs the same process as S140, that is, the process of setting the time T1 calculated in S130 in the energization on time setting unit. In step S180, the microcomputer 11 turns on the energization determination flag, and then ends the crank synchronization process.

If the microcomputer 11 makes a negative determination in S110, that is, if the current activation of the crank synchronization processing is not activation immediately before injection, the microcomputer 11 proceeds to S190.
In S190, the microcomputer 11 determines whether or not the previous activation of the crank synchronization processing was activation immediately before injection. In other words, in S190, it is determined whether or not the current activation of the crank synchronization process is immediately after the requested injection position RA.

If the microcomputer 11 makes a negative determination in S190, it ends the crank synchronization process as it is. If it makes a positive determination in S190, it proceeds to S200.
In S200, the microcomputer 11 determines whether or not the energization determination flag is on. If the energization determination flag is on, the microcomputer 11 proceeds to S210 and turns off the energization determination flag. Thereafter, the crank synchronization process is terminated.

  If the microcomputer 11 determines in S200 that the energization determination flag is not on (that is, off), the microcomputer 11 determines that the injector 5 is not energized, that is, the injector 5 is not driven. The process proceeds to S220 and energization of the injector 5 is started. Then, in the next S230, the microcomputer 11 performs the same process as S320 of FIG. 4, that is, the process of setting the energization off time. Further, the microcomputer 11 cancels the start of the delay trigger event process in the next S240, and thereafter ends the crank synchronization process. If the process of S160 is not performed at the previous execution of the crank synchronization process, S240 can be skipped.

[2-3. Delay trigger event processing]
As shown in FIG. 6, when starting the delay trigger event process, the microcomputer 11 variably sets the determination value Aj used for the determination process in the next S520 in accordance with the engine rotation speed in S510. The microcomputer 11 sets the determination value Aj to a larger value as the engine speed increases, for example, based on a predetermined data map or calculation formula.

  In step S520, the microcomputer 11 performs a determination process for determining whether or not the current crank position is more than the determination value Aj from the required injection position RA. That is, the microcomputer 11 determines whether or not the current crank position is more than the determination value Aj before the required injection position RA.

  When the microcomputer 11 makes an affirmative determination in the determination process of S520, the microcomputer 11 proceeds to S530 and performs the same process as S140 of FIG. That is, in S530, the microcomputer 11 calculates the time T2 from the current time to the timing of the required injection position RA based on the current engine speed, and resets the calculated time T2 in the above-described energization on time setting unit. . In step S540, the microcomputer 11 turns on the energization determination flag, and then ends the delay trigger event process.

If the microcomputer 11 makes a negative determination in the determination process in S520, the microcomputer 11 proceeds directly to S550, turns on the energization determination flag, and ends the delay trigger event process.
[4. Example of action]
An example of the effect of the processing in FIGS. 3 to 6 will be described with reference to FIG.

  In the example of FIG. 7, the required injection position RA calculated in the time synchronization process of FIG. 2 is, for example, BTDC 65 ° CA. For this reason, in the crank synchronization process started at BTDC 90 ° CA, it is determined in S110 that the current start is the start immediately before injection. In the crank synchronization process started at BTDC 60 ° CA, it is determined in S190 that the previous start was the start immediately before injection. In the following description, crank synchronization processing started at BTDC 90 ° CA is referred to as crank synchronization processing at BTDC 90 ° CA, and crank synchronization processing started at BTDC 60 ° CA is referred to as crank synchronization processing at BTDC 60 ° CA.

  In FIG. 7, the crank signal at the first stage represents the crank signal when the engine speed is constant. And the part of (b) represents the case where the engine rotational speed becomes smaller in the rear than before BTDC 90 ° CA, that is, the case where the engine decelerates. The part (c) represents the case where the engine speed does not change before and after BTDC 90 ° CA, that is, the case where there is no acceleration / deceleration of the engine. Further, the portion (d) represents the case where the engine rotational speed is increased after BTDC 90 ° CA, that is, the case where the engine is accelerated.

  In the crank synchronization process of BTDC 90 ° CA, the energization determination flag is turned off for initialization in S120, and the time T1 from the current time to the timing of the required injection position RA is determined based on the current engine speed in S130. Calculated. In S135, it is determined whether or not the time T1 is equal to or longer than the predetermined time Tc. If it is determined that “T1 ≧ Tc”, not only the energization on time is set in S140, In S160, the delay trigger time is set. As shown in the part (a) in FIG. 7, the energization on time set in S140 is the time t1 when the time T1 has elapsed from the time of BTDC 90 ° CA. The delay trigger time set in S160 is the time t2 when the time Td shorter than the time T1 by the predetermined time α has elapsed from the time of BTDC 90 ° CA, that is, the time t2 before the time t1 by the predetermined time α. Become.

  Here, as shown in part (c) of FIG. 7, when there is no acceleration / deceleration of the engine, the delay trigger event process of FIG. 6 is started at time t2. In the case of the example shown in part (c), in the delay trigger event process, it is determined in S520 that the current crank position is not separated by more than the determination value Aj from the required injection position RA. The power supply determination flag is turned on in S550 without resetting. Therefore, when the energization on time (that is, time t1) set in the crank synchronization process of BTDC 90 ° CA arrives, the energization on process of FIG. 4 is activated and the energization of the injector 5 is started. Thereafter, when the drive time TQ elapses, the energization-off process of FIG. 5 is started and the energization of the injector 5 is terminated. In this case, in the crank synchronization process of BTDC 60 ° CA, it is determined in S200 that the energization determination flag is on, and in S210, the energization determination flag is turned off.

  On the other hand, as shown in the part (b) of FIG. 7, even when the engine decelerates, the delay trigger event process of FIG. 6 is started at the time t2. In the example shown in part (b), in the delay trigger event process, it is determined in S520 that the current crank position is more than the determination value Aj from the required injection position RA, and as a result, in S530, The energization on time is reset, and the energization determination flag is turned on in S540. In S530, the time T2 from the present time to the timing of the required injection position RA is calculated based on the current engine speed, and the time t3 when the time T2 has elapsed is reset as the energization on time. When the energization-on time (that is, time t3) reset by this delay trigger event process arrives, the energization-on process of FIG. 4 is started and energization of the injector 5 is started. Thereafter, when the drive time TQ elapses, the energization-off process of FIG. 5 is started and the energization of the injector 5 is terminated. Also in this case, in the crank synchronization process of BTDC 60 ° CA, it is determined in S200 that the energization determination flag is on, and in S210, the energization determination flag is turned off.

  Thus, when the timing of the required injection position RA is delayed by the deceleration of the engine from the energization-on time (that is, time t1) set in the crank synchronization process of BTDC 90 ° CA, the delay trigger event before time t1. In the process, the power-on time is reset. For this reason, it is suppressed that the energization start timing of the injector 5 shifts from the timing of the required injection position RA.

  Further, as shown in the part (d) of FIG. 7, the engine accelerates and before the delay trigger time (ie, time t2) set in the crank synchronization processing of BTDC 90 ° CA, the BTDC 60 ° CA Assume that the crank synchronization process is activated. In this case, the crank synchronization process of BTDC 60 ° CA is started without turning on the energization determination flag in the delay trigger event process. Therefore, in the crank synchronization process of BTDC 60 ° CA, since it is determined in S200 that the energization determination flag is off, it is determined that the injector 5 is not energized. As a result, in the crank synchronization process of BTDC 60 ° CA, energization of the injector 5 is immediately started in S220, and the energization off time is set in S230. It should be noted that the energization determination flag may be turned on not in the delay trigger event process but in the energization on process.

  As described above, when the crank synchronization processing of BTDC 60 ° CA is started at the time when the power to the injector 5 has not been performed due to the acceleration of the engine, the crank synchronization processing of BTDC 60 ° CA is immediately performed to the injector 5. Energization is started. For this reason, even when the engine is accelerated, it is suppressed that the energization start timing of the injector 5 deviates from the timing of the required injection position RA.

  If it is determined in S135 in the BTDC 90 ° CA crank synchronization process that the time T1 is not equal to or greater than the predetermined time Tc, the energization on time is set in S170, but the delay trigger time is not set. . For this reason, the energization-on process is started at the energization-on time set in S170.

[4. effect]
According to the embodiment described in detail above, the following effects can be obtained.
(A) In the crank synchronization process, the microcomputer 11 calculates a time T1 until the crank position becomes the required injection position RA based on the current engine speed when the current start is the start immediately before injection. . Then, the energization on time is set so that the energization on process starts when the calculated time T1 has elapsed. Further, in the crank synchronization process, the microcomputer 11 starts the delayed event trigger process at a time that is a predetermined time α before the set energization on time when the current start is a start immediately before injection. Set the delay trigger time. In the delay trigger event process, the microcomputer 11 calculates a time T2 until the crank position reaches the required injection position RA based on the current engine speed, and the energization-on process is performed when the time T2 has elapsed. Reset the power-on time so that it starts.

  For this reason, even if the engine decelerates after the energization on time is set by the crank synchronization process and the actual timing of the required injection position RA is delayed from the set energization on time, the delay event trigger process As a result, the energization-on time is reset. Therefore, it is possible to suppress the drive start timing of the injector 5 from deviating from the timing of the required injection position RA due to engine deceleration.

  (B) In the crank synchronization process, the microcomputer 11 changes the predetermined time α for setting the delay trigger time according to the engine speed. Specifically, the predetermined time α is set to a longer time as the engine speed increases. For this reason, the margin time from the time when the delay trigger event process is activated to the timing of the requested injection position RA, that is, the margin time for resetting the energization on time by the delay trigger event process can be optimized.

  As a comparative example, if the predetermined time α is a short constant value, for example, the time T2 shown in the portion (b) in FIG. Therefore, there is a possibility that it may not be in time to reset the energization on time by the delay trigger event process before the timing of the required injection position RA arrives. For example, if the predetermined time α is a long and constant value, the time T2 shown in part (b) in FIG. Therefore, the energization on time is reset by the delay trigger event process well before the timing of the required injection position RA.

On the other hand, the inconvenience when the predetermined time α is set to a constant value can be suppressed by making the predetermined time α variable according to the engine speed as in the present embodiment.
(C) In the delay trigger event process, the microcomputer 11 performs the determination process of S520 that determines whether or not the current crank position is more than the determination value Aj from the required injection position RA, and makes a negative determination in this determination process. In such a case, the power-on time resetting process is not performed.

  If a negative determination is made in the determination process of S520, it is considered that the current crank position to the required injection position RA is less than the determination value Aj, and the timing of the required injection position RA comes soon. For this reason, the energization on time is not reset and the energization on time set in the crank synchronization process is made valid. For this reason, the process for resetting the energization on time can be omitted as appropriate, and the processing load on the ECU 1, that is, the processing load on the microcomputer 11 in this embodiment can be suppressed.

  (D) In the delay trigger event process, the microcomputer 11 changes the determination value Aj used in the determination process of S520 according to the engine speed. Specifically, the determination value Aj is set to a larger value as the engine speed increases. Therefore, the determination value Aj can be set to an appropriate value.

  As a comparative example, if the determination value Aj is a small constant value, for example, the energization-on time is reset by delay trigger event processing, which is preferable in terms of fuel injection accuracy. However, when the determination value Aj is a small value at the time of high engine rotation, there is a possibility that the process for resetting the energization on time may not be in time for the required injection position RA.

On the other hand, by making the determination value Aj variable according to the engine speed as in this embodiment, inconveniences when the determination value Aj is set to a constant value can be suppressed.
(E) In the crank synchronization process, the microcomputer 11 determines whether or not the injector 5 is driven based on the energization determination flag in S200 when the current activation is activation immediately after the required injection position RA. And when it determines with the injector 5 not being driven, the drive of the injector 5 is started in S220 of the said crank synchronous process.

  For this reason, when the crank synchronization processing after the timing of the required injection position RA is started by the acceleration of the engine when the injector 5 is not driven yet, the injector 5 is immediately performed by the crank synchronization processing at that time. Is driven. Therefore, even when the engine is accelerated, it is possible to prevent the drive start timing of the injector 5 from deviating from the timing of the required injection position RA.

  In the above embodiment, the microcomputer 11 functions as each of a calculation unit, a drive start unit, a setting processing unit, and a resetting unit. 2 corresponds to processing as a calculation unit, S310 in FIG. 4 corresponds to processing as a drive start unit, and S110 to S240 in FIG. 3 correspond to processing as a setting processing unit. S510 to S550 in FIG. 6 correspond to processing as the resetting unit.

[5. Other Embodiments]
As mentioned above, although embodiment of this indication was described, this indication is not limited to the above-mentioned embodiment, and can carry out various modifications.

  For example, the functions of the energization on process and the energization off process may be realized by a hardware timer circuit configured inside or outside the microcomputer 11. In addition, a plurality of functions of one constituent element in the above-described embodiment may be realized by a plurality of constituent elements, or one function of one constituent element may be realized by a plurality of constituent elements. Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or a single function realized by a plurality of constituent elements may be realized by one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

  In addition to the above-described ECU, a system including the ECU as a constituent element, a program for causing a computer to function as the ECU, a non-transition actual recording medium such as a semiconductor memory storing the program, a fuel injection control method, and the like The present disclosure can be realized in various forms.

  1 ... ECU, 5 ... injector, 11 ... microcomputer

Claims (5)

A calculation unit (11, S105) configured to calculate the crank position of the engine to start driving the injector (5) for injecting fuel into the engine as a required injection position;
A drive start unit (11, S310) configured to start when the set start time arrives and to start driving the injector;
The engine is started every time the crankshaft rotates by a predetermined angle, and when the current start is the start immediately before the required injection position calculated by the calculation unit, based on the current rotation speed of the crankshaft. A setting process configured to calculate the time until the crank position reaches the required injection position and set the start time of the drive start unit so that the drive start unit starts when the time elapses Part (11, S110 to S240),
Furthermore, the setting processing unit
When the current activation of the setting processing unit is the activation immediately before the requested injection position, the drive start is performed at a time that is a predetermined time before the activation time of the drive start unit set by the setting processing unit. The resetting unit (11, S510 to S550) for resetting the startup time of the unit is configured to start so as to set the startup time of the resetting unit,
The resetting unit
When activated, as a resetting process (S530) for resetting the startup time of the drive start unit, the time until the crank position becomes the required injection position is calculated based on the current rotational speed of the crankshaft, A process for resetting the activation time of the drive start unit so that the drive start unit is activated when the time has elapsed,
Fuel injection control device. The fuel injection control device according to claim 1,
The setting processing unit
The predetermined time is configured to be changed according to the rotational speed of the crankshaft (S150).
Fuel injection control device. The fuel injection control device according to claim 1 or 2,
The resetting unit
When activated, a determination process (S520) is performed to determine whether or not the current crank position is more than a predetermined determination value from the required injection position. If the determination process is affirmative, the reset process is performed. If the determination process is negative, the reset process is not performed.
Fuel injection control device. The fuel injection control device according to claim 3,
The resetting unit
The determination value is configured to be changed according to the rotation speed of the crankshaft (S510).
Fuel injection control device. A fuel injection control device according to any one of claims 1 to 4,
The setting processing unit
When the current activation of the setting processing unit is activation immediately after the required injection position, it is determined whether or not the injector is driven by the drive start unit (S200), and the injector is not driven. If determined, the injector is configured to start driving (S220).
Fuel injection control device.

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