JP6328067B2 - Fuel injection control device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel injection control device for an internal combustion engine.

  In recent years, in particular, in fuel injection control of an in-cylinder direct injection internal combustion engine, in order to increase the degree of freedom of in-cylinder air-fuel mixture formation, multistage injection technology has been adopted in which injection per cycle is divided into several stages. Yes.

  When the injection per cycle is divided into several stages and injected, a small injection with a small injection amount requirement per injection may be required depending on the division ratio.

  Therefore, various companies are actively developing technologies to expand the range of the maximum injection amount and the minimum injection amount (hereinafter referred to as dynamic range) of the fuel injection valve. In particular, in order to further reduce the minimum injection amount while securing the conventional maximum injection amount, so-called half lift control that controls aggressive fuel injection from a state in which the fuel injection valve does not open completely has attracted attention.

  In the prior art, improvement is performed in a state in which the valve body collides with the stopper after starting the valve opening and is held at a constant lift amount (hereinafter referred to as a full lift state) (see, for example, Patent Document 1). In the technology disclosed in Patent Document 1, the fuel injection valve mechanism is improved and the drive current of the fuel injection valve is set so that the lift amount of the valve body can be opened in two stages of high lift and low lift. In addition, a technique for expanding the dynamic range by switching the injection amount characteristic of the fuel injection valve has been introduced.

  On the other hand, in the technology for reducing the minimum injection amount using the half lift state, when the valve opening time instruction value is minimal, the fuel injection valve does not open at all and the valve opening instruction value that starts opening after the valve opening instruction value is fully lifted. The technology that precisely controls the valve opening instruction value between the valve opening instruction values and the drive current waveform of the fuel injection valve are actively controlled to make the lift amount and valve closing timing appropriate, and the stable minimum fuel Technologies for realizing the injection amount are being developed.

Japanese Patent Laid-Open No. 2002-266722

  Half lift control is expected to reduce the minimum injection amount, but the fuel depends on the environment of the fuel injection valve, that is, the temperature of the fuel injection valve itself, the temperature of the internal combustion engine, the temperature of the cooling water and the lubricating oil of the internal combustion engine, etc. When the viscosity of the fuel at the time of injection changes, the valve closing timing of the valve body of the fuel injection valve, particularly the valve closing timing, changes, causing a problem that the injection amount changes.

  The objective of this invention is providing the fuel-injection control apparatus which can suppress the dispersion | variation in the injection amount at the time of a half lift by the change of the viscosity of a fuel.

To achieve the above object, the present invention boosts a first voltage supplied from a battery and generates a second voltage higher than the first voltage, and a fuel in a combustion chamber of an engine. The voltage applied to the injector that directly injects is switched to the first voltage or the second voltage, the switch that turns on / off the current that flows through the injector, and the injector is fully opened according to the operating state of the engine A half-lift control unit that controls the switch so as to complete the fuel injection by closing the valve before, and is applied to the injector so that the fuel injection amount decreases as the viscosity of the fuel increases. A current waveform correction unit that corrects a waveform of a current to be applied, and the current waveform correction unit flows into the injector while the second voltage is applied to the injector. A peak current value indicating the maximum current value, a peak current arrival time indicating a time from when the second voltage is applied until the current flowing through the injector reaches the peak current value, and the first voltage. It is a fuel injection control device that reduces at least one of the holding current values indicating the current value for holding the valve opening flowing through the injector by switching, and whether the half lift control unit is operating or not. The current waveform correction unit corrects the waveform of the current applied to the injector only when it is determined that the half lift control unit is operating, The half lift control unit opens the valve by energizing the injector with the second voltage, and interrupts the energization of the injector before the injector is fully opened. And, the valves behavior as half lift state, after interrupting the energization of the injector, in which to adjust the lift amount of half the lift by the length of time for energizing to the injector at the first voltage .

  According to the present invention, it is possible to suppress variations in the injection amount during half lift due to changes in the viscosity of the fuel. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a figure which shows an example of a structure of the system containing the fuel-injection control apparatus by embodiment of this invention. FIG. 2 is a configuration diagram of a fuel injection valve driving unit shown in FIG. FIG. 2 is a diagram showing a first drive waveform of current applied to the fuel injection valve shown in FIG. FIG. 4 is a diagram for explaining an injection amount characteristic when the first drive waveform shown in FIG. 3 is used. FIG. 4 is a diagram showing a second drive waveform of current applied to the fuel injection valve shown in FIG. FIG. 6 is a diagram for explaining an injection amount characteristic when the second drive waveform shown in FIG. 5 is used. FIG. 4 is a correlation diagram of fuel temperature and fuel viscosity. FIG. 6 is a correlation diagram of changes in fuel temperature and fuel injection amount. It is a correlation diagram of the behavior of an injection pulse signal and a fuel injection valve. FIG. 4 is a diagram for explaining an operation for correcting the first drive waveform shown in FIG. FIG. 6 is a diagram for explaining an operation of correcting the second drive waveform shown in FIG.

  Hereinafter, the configuration and operation of a fuel injection control apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an example of the configuration of a system including a fuel injection control device (101) according to an embodiment of the present invention. First, the battery voltage (109) supplied from the battery is supplied to the fuel injection control device (101) provided in the ECM (not shown) via the fuse (103) and the relay (104).

  Next, the configuration within the fuel injection control device (101) will be described. The fuel injection control device (101) includes a fuel injection valve drive control unit (102), a drive IC (105), a high voltage generation unit (106: booster), and a fuel injection valve drive unit (107a, 107b).

  The fuel injection valve drive control unit (102) includes a microcomputer and functions as a fuel injection valve pulse signal calculation block (102a), a fuel injection valve drive waveform command block (102b), and a parameter input block (102c). The microcomputer includes a CPU (arithmetic unit), a memory (storage device), an IO port, and the like.

  Based on the battery voltage (109), the high voltage generator (106) is a high power supply voltage (hereinafter, referred to as “high power source voltage”) required when the valve body provided in the electromagnetic solenoid fuel injection valve (108: injector) is opened. High voltage: 110) is generated. The high voltage generator (106) boosts the battery voltage (109) so as to reach a desired target high voltage based on a command from the drive IC (105).

  That is, the high voltage generation unit (106) boosts the battery voltage (109) supplied from the battery, and generates a high voltage (110) higher than the battery voltage (109). Thus, as a power source for the fuel injection valve (108), a high voltage (110) for the purpose of securing the valve opening force of the valve body and a battery voltage that keeps the valve body open so that the valve body does not close after the valve is opened ( 109).

  In addition, fuel injection valve drive units (107a, 107b) are provided on the upstream side and the downstream side of the fuel injection valve (108) to supply drive current to the fuel injection valve (108). Details will be described later with reference to FIG.

  The high voltage generation unit (106) and the fuel injection valve drive unit (107a, 107b) are controlled by the drive IC (105) to apply the high voltage (110) or the battery voltage (109) to the fuel injection valve (108). Then, control is performed to achieve a desired drive current. The drive IC (105) also displays the drive period of the fuel injection valve (106) (the energization time of the fuel injection valve (108)), the selection of the drive voltage, and the set value of the drive current in an ECU (not shown). Control is performed based on the command values calculated by the fuel injector pulse signal calculation block (102a) and the fuel injector drive waveform command block (102b) provided in the block 102.

  Next, the fuel injection valve drive unit (107a, 107b) will be described with reference to FIG. FIG. 2 is a configuration diagram of the fuel injection valve driving section (107a, 107b) shown in FIG.

  As described with reference to FIG. 1, the drive unit (107a) upstream of the fuel injection valve (108) supplies a current required to open the fuel injection valve (108), so that the high voltage (110) Is supplied to the fuel injection valve (108) from the high voltage generation unit (106) of FIG. 2 through the diode (201) provided for preventing current backflow using the circuit TR_Hivboost (203) of FIG.

  Note that the circuit TR_Hivboost (203) is composed of a transistor (switching element) as an example. The same applies to a circuit TR_Hivb (204) described later.

  On the other hand, after the fuel injection valve (108) is opened, the battery voltage (109) necessary for maintaining the valve open state of the fuel injection valve (108) is changed to the reverse current as in the high voltage (110). It supplies to a fuel injection valve (108) through the diode (202) for prevention using the circuit TR_Hivb (204) of FIG.

  Next, the fuel injection valve drive unit (107b) downstream of the fuel injection valve (108) includes TR_Low (205). By turning this drive circuit TR_Low (205) ON, the power supplied from the upstream fuel injection valve drive section (107a) can be applied to the fuel injection valve (108). Further, by detecting the current consumed by the fuel injection valve (108) by the shunt resistor (206), current control of the desired fuel injection valve (108) described later is performed.

  This description shows an example of a method for driving the fuel injection valve (108) .For example, when the fuel pressure is relatively low, the high voltage (110) is generated when the fuel injection valve (108) is opened. Instead, the battery voltage (109) may be used.

  The fuel injection valve drive unit (107a, 107b) switches the voltage applied to the fuel injection valve (108) that directly injects fuel into the combustion chamber of the engine to the battery voltage (109) or the high voltage (110), and It functions as a switch for turning on / off the current flowing through the injection valve (108).

  Next, current control of the fuel injection valve (108), which is the basis of the embodiment of the present invention, will be described using FIG. 3 and FIG. FIG. 3 is a diagram showing a first drive waveform of the current applied to the fuel injection valve (108) shown in FIG. FIG. 4 is a diagram for explaining an injection amount characteristic when the first drive waveform shown in FIG. 3 is used.

  Generally, when driving a fuel injection valve (108) of a direct injection type internal combustion engine, a current waveform (302) is set in advance based on the characteristics of the fuel injection valve (108), and the current waveform (302) The injection amount characteristic of the fuel injection valve (108) is recorded in an ECU (not shown). The fuel injection control device (101) determines the drive command time (hereinafter referred to as the fuel injection valve (108)) from the operating state (intake air amount) of the internal combustion engine (not shown) and the injection amount characteristic of the fuel injection valve (108). , Pulse signal: 301) is calculated.

  FIG. 3 shows an example of this control method, which is defined as a first drive current waveform control method.

  The pulse signal (301) is turned ON from the desired injection timing (T304) calculated by the ECM, and the current control of the fuel injection valve (108) is performed based on the drive current waveform (302) stored in the ECM in advance. Done.

  The drive current waveform (302) in the example of FIG. 3 includes a valve opening peak current (302a) for opening the fuel injection valve (108), a first holding current (302b) for holding the valve open, and a second holding current ( 302c) and the like. The fuel injection control device (101) operates the fuel injection valve (108) by switching the respective target current values (302a, 302b, 302c in FIG. 3) based on a preset control sequence, The drive current is continuously applied to the fuel injection valve (108) until T308 when the pulse signal (301) is turned off.

  Next, the valve body behavior of the fuel injection valve (108) will be described. The high voltage is applied to the fuel injection valve (108) from when the pulse signal is turned ON (T304) until the valve opening peak current (302a) is reached. The valve element starts to open from the point in time (T305 in FIG. 3) when the residual magnetic field becomes a predetermined amount based on the electrical characteristics unique to the fuel injection valve.

  After that, the valve opening force due to the valve opening peak current (current behavior up to 302a) continues, so that the valve body continues the valve opening operation, and the valve body reaches the stopper position on the valve opening side (T306). ). At that time, due to the excessive valve opening force, the valve element generates a bouncing operation for a while (period 310) and shifts to a stable valve opening state (T307).

  After that, the valve body remains fully open until the pulse signal is turned off (T308). After that, the residual magnetic field of the fuel injection valve (108) decreases and the valve body is completely closed. Closes (T309).

  In this behavior, a state in which the valve body is completely opened is defined as a full lift state in the embodiment of the present invention.

  When the pulse signal is turned off before reaching the valve opening peak current (302a), the current drops as shown by the broken line (304), and the valve that draws a parabola as shown by the broken line (305). It becomes a behavior. This behavior is defined as a half lift state in the embodiment of the present invention.

  Here, the fuel injection valve drive control unit (102) and the drive IC (105) allow the fuel injection valve (108) to be fully opened according to the operating state of the engine (engine speed, intake air amount, air-fuel ratio, etc.). It functions as a half lift control unit that controls the fuel injection valve drive unit (107a, 107b) so as to complete the fuel injection by closing the valve before.

  Next, the injection amount characteristic when the drive current (302) of FIG. 3 is used will be described with reference to FIG.

  It has been explained that the injection amount characteristic is determined from the drive current waveform (302) and the period in which the pulse signal (301) is ON. When the fuel injection amount for each hour is taken as the vertical axis, the characteristics shown in 401 are obtained.

  To describe this in detail, the period from the time when the valve body starts to open (T305) to the time when the valve body reaches full lift (T306) (402) is based on the supply time of the valve opening peak current (302a). As the lift amount of the valve body increases, the fuel injection amount increases.

  During this period, the slope of the fuel injection amount (401a) is determined according to the valve opening speed, and the power supply voltage of the peak current depends on the high voltage (110). It becomes. Therefore, more precise pulse signal (301) control is required, but this period is defined as the first half lift region in the embodiment of the present invention.

  However, the first half lift region according to the first drive current waveform control method described above is a region where the flow rate characteristic due to the bouncing (the period of 310) is not stable (403) between the flow rate characteristic of the full lift region. ) Exists. Therefore, there is a difficulty that it is difficult to control the fuel due to the connection from the half lift (402) to the full lift (404).

  Therefore, a second drive current waveform control method having a second half lift region in which the controllability by the pulse signal is improved in the connection from the half lift to the full lift is also described. Next, this control will be described.

  FIG. 5 is a diagram showing a second drive waveform of the current applied to the fuel injection valve (108) shown in FIG.

  First, the drive current waveform includes a peak current supply period (T501-T502) for generating a magnetic force necessary for the valve opening operation of the valve body provided in the fuel injection valve (108). During this period, the pulse signal (501) is turned on (T501), and the drive current (502) reaches either the valve opening peak current or until a predetermined period (T502) is established, The fuel injection valve (108) is driven by the high voltage (110) in the same manner as the valve opening peak current shown in FIG.

  In addition, this peak current supply period (T501-T502) is longer than the current that can be surely opened even under the maximum fuel pressure in which the fuel injection valve (108) is used, or more than the corresponding period (T501-T502). It is necessary to be.

  After the conditions for completing the peak current supply period are satisfied, the drive current waveform has a lift amount adjustment period (T503-T505) in which a current smaller than the peak current is supplied to the fuel injection valve (108) for a predetermined period. The lift amount of the valve body is controlled according to the height.

  In addition, after the peak current supply period (T501-T502) and before the shift to the lift amount adjustment period (T503-T506), the drive current waveform includes a current cutoff period (T502-T503) that quickly decreases the peak current. It is characterized by that. This reduces the excessive valve opening force generated during the peak current supply period, eliminates the above-described bouncing of the valve body, and realizes the lift amount adjustment (half lift) period, thereby smoothly moving to the full lift state. It is possible to migrate.

  Here, the fuel injection valve drive control unit (102) and the drive IC (105) switch the voltage applied to the fuel injection valve (108) to the high voltage (110) and turn on the current flowing through the fuel injection valve (108). After that, the current flowing through the fuel injection valve (108) is set to 0, the voltage applied to the fuel injection valve (108) is then switched to the battery voltage (109), and the current flowing through the fuel injection valve (108) is turned on / off. The fuel injection valve drive unit (107a, 107b) is controlled to turn off.

  Next, the injection amount characteristic when the drive current (502) in FIG. 5 is used will be described with reference to FIG.

  From the time (T601) when the valve body starts the valve opening operation, the injection amount characteristic (601) rises to the time (T604) when the peak current is reached, and shifts to the current cutoff period (T604-T602). In the current interruption period, the drive current does not change and the valve behavior follows the same locus no matter where the pulse signal is turned off.

  Therefore, the injection amount characteristic (601) becomes a flat characteristic until the time point (T602) when the current interruption period (T604-T602) is completed, and thereafter, the flow proceeds to the lift amount adjustment period (603) and the valve-opening holding current supply is performed. As a result, the injection amount characteristic starts to rise again. In the embodiment of the present invention, the region realized in this lift amount adjustment period is defined as the second half lift region.

  As explained in the valve behavior of FIG. 5, in the second drive current waveform control method, there is a large difference in the gradient of the injection amount characteristic between the half lift period (603) and the full lift period (604). Will not occur.

  As described above, the fuel injection device and the fuel injection valve driving method according to the embodiment of the present invention, particularly, the half lift control method has been described. However, the injection pulse region in which the fuel injection valve can be controlled by the half lift is extremely different from the full lift control region. It turns out that it becomes a narrow range.

  On the other hand, with respect to at least one of the divided injections, such as in the case of multi-stage injection in which the required injection amount (pulse width) per cycle is divided into a plurality of stages to form an in-cylinder mixture of the internal combustion engine In some cases, fuel injection (amount) in the half lift region may be required.

  At this time, the injection pulse width in the half lift region varies depending on the operating state of the internal combustion engine, that is, information that changes every moment, such as the rotational speed, the intake air amount, and the air-fuel ratio. However, since the multi-stage injection operation permission condition is determined so as to operate in this fluctuation range, the required half lift region does not deviate unintentionally.

  However, depending on the conditions under which the internal combustion engine is operated, the temperature of the fuel injected from the fuel injection valve changes. For example, although the internal combustion engine starts from a cold state and reaches a warm-up state, the temperature of the fuel gradually changes although it is slow compared with a change in the amount of air.

  Therefore, the viscosity of the fuel changes depending on the temperature of the injected fuel, affects the behavior of the valve body of the fuel injection valve, and the injection amount changes even with the same injection pulse width.

  7A to 7C show the correlation between the fuel temperature, the fuel viscosity, and the injection amount. FIG. 7A is a correlation diagram between fuel temperature and fuel viscosity. FIG. 7B is a correlation diagram between changes in fuel temperature and fuel injection amount. FIG. 7C is a correlation diagram between the injection pulse signal and the behavior of the fuel injection valve.

  As shown in FIG. 7A, the lower the temperature of the injected fuel, the higher the viscosity of the fuel, and the tendency of the valve body moving speed of the fuel injection valve to be suppressed. Therefore, as shown in FIG. 7C, it is known that the valve closing timing is particularly delayed, and as a result, the injection amount increases. That is, as shown in FIG. 7B, the lower the fuel temperature, the larger the fuel injection amount change.

  Furthermore, since the valve closing delay time of the valve body does not depend on the pulse width, the change in the injection amount during the half lift control, which is a minute injection amount, becomes larger than that during the full lift.

  For injection in the full lift region, the method of correcting the injection pulse width is generally used. However, as described above, the range of the pulse width that can be half-lifted is narrow, and a correction amount request by the pulse width is also required. growing. For this reason, the correction by the pulse width deviates from the half lift region, and the possibility that the required minute injection amount cannot be obtained becomes very high.

  In order to solve such a problem, at the time of half lift control, the fuel temperature correlated with the viscosity of the fuel, and further, the cooling water temperature representative of the temperature of the internal combustion engine that affects the temperature of the fuel to be actually injected. By correcting the current waveform, not the injection pulse width, with the correction value set based on the lubricating oil temperature, the injection amount that changes depending on the viscosity of the fuel is stabilized.

  8 and 9 show an outline of the current waveform correction operation of the present invention. FIG. 8 is a diagram for explaining an operation for correcting the first drive waveform shown in FIG. FIG. 9 is a diagram for explaining an operation of correcting the second drive waveform shown in FIG.

  FIG. 8 shows the correction operation in the case of the first half-lift region described above. In correcting the current waveform, only the peak current value (Ipeak) for full lift control is corrected.

  The parameters for determining the current waveform are the peak current, the first holding current, and the second holding current as described above with reference to FIG. 3, but the first and second holding currents are effective only in the full lift control state. It is. As a result, the only parameter that can vary the valve lift amount of the first half lift is only the peak current.

  FIG. 9 shows the correction operation in the case of the second half lift region described above.

  In the half lift region of the peak current supply period (T501-T502), that is, the period in which the valve behavior is the same as that of the first half lift region defined in the embodiment of the present invention, the same as described above with reference to FIG. The peak current value (I peak) can be selected for correction, or the timing (T902) for starting the current interrupting operation can be selected for correction.

  However, from the viewpoint of controllability, it is desirable to set the timing (T902) for starting the current interrupting operation as a correction target.

  However, since the lift amount adjustment period (T903-T904) is the main half lift region from the main point of the second drive current waveform control, the valve opening holding current (I hold) is the main correction target.

  Next, a specific current waveform correction method will be described.

  First, in the fuel injection valve drive waveform command block (102b) in FIG. 1, a peak current command value required at the reference fuel temperature is preset.

  Further, the fuel injection valve drive waveform command block (102b) is inputted with the fuel temperature, the cooling water temperature of the internal combustion engine, and the lubricating oil temperature, and the injection obtained at the reference fuel temperature according to the fuel temperature among these temperatures. The peak current value is corrected by multiplying the reference value by a correction coefficient necessary to make it equal to the amount.

  Here, regarding the fuel temperature, the temperature in the injection nozzle orifice that affects the valve body operation should be referred to. However, when temperature detection is performed by a fuel temperature sensor or the like, it is difficult to measure the temperature in the nozzle part due to restrictions on the mounting layout of the sensor. Therefore, for example, the temperature inside the pressure accumulating portion (common rail) upstream of the injection valve must be referred to, and the temperature inside the nozzle portion that changes due to the influence of heat received from the internal combustion engine cannot be detected accurately.

  Therefore, the parameter input block (102c) inputs the coolant temperature and the lubricating oil temperature, which are representative of the temperature of the internal combustion engine, to the fuel injection valve drive waveform command block (102b), and corrects the fuel temperature according to these temperatures. By correcting the current correction value, more accurate correction is possible.

  In addition, when a fuel temperature sensor cannot be used from the viewpoint of cost, the fuel temperature may be estimated or direct current correction may be performed according to the coolant temperature or the lubricating water temperature close to the nozzle part temperature.

  Here, the fuel injection valve drive waveform command block (102b) indicates that the fuel injection amount decreases as the temperature correlated with the fuel viscosity (cooling water temperature, lubricating oil temperature, fuel temperature, etc.) decreases. It functions as a current waveform correction unit that corrects the waveform of the current applied to the fuel injection valve (108).

  More specifically, as shown in FIG. 9, the fuel injection valve drive waveform command block (102b) has a low temperature (cooling water temperature, lubricating oil temperature, fuel temperature, etc.) correlated with the viscosity of the fuel. Accordingly, at least one of the peak current value, the peak current arrival time, and the holding current value is reduced.

  Here, the peak current value is the maximum value of the current flowing through the fuel injection valve (108) while the high voltage (110) is applied to the fuel injection valve (108). The peak current arrival time is the time (period) from when the high voltage (110) is applied until the current flowing through the fuel injection valve (108) reaches the peak current value. This is the current value for maintaining the valve opening flowing in the fuel injection valve (108) by switching the battery voltage (109).

  As a result of the above correction operation, as shown in the schematic diagram of the lift amount in FIGS. 8 and 9, the injection amount is controlled to be equal to the reference value regardless of whether the fuel temperature is equal to or higher than the reference value. .

  The correction coefficient is preferably determined in advance according to the characteristics of the injection valve, and is set so as not to fall below the minimum peak current that can be opened and the minimum opening holding current that can be held open. Should.

  The fuel injection valve drive waveform command block (102b) is also input with fuel pressure information applied to the injection valve (108) so as to compensate for the valve closing delay that changes according to the fuel pressure. Yes. Compensation is possible by correcting the current correction value corresponding to the aforementioned temperature to be a smaller value as the fuel pressure is higher than the reference fuel pressure.

  In other words, the fuel injector drive waveform command block (102b) has at least one of a peak current value, a peak current arrival time, and a holding current value as the fuel pressure applied to the fuel injector (108) decreases. Make it smaller.

  Note that the execution condition of the current value correction control according to the embodiment of the present invention is programmed to be executed only in the half lift region.

  That is, the fuel injection valve drive control unit (102) functions as a determination unit that determines whether or not the half lift control unit is operating. The fuel injection valve drive control unit (102) corrects the waveform of the current applied to the fuel injection valve (108) only when it is determined that the half lift control unit is operating.

  Accordingly, the current value corrected by the half lift is not used in the full lift region, and for example, it is possible to prevent unintentional valve closing when the current value corrected to a small value is shifted to the full lift region. .

  According to the present embodiment, it is possible to suppress variations in the injection amount during half lift due to changes in the viscosity of the fuel.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed.

  For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  In the above embodiment, the fuel injection valve drive waveform command block (102b) is configured such that the current applied to the fuel injection valve (108) decreases so that the fuel injection amount decreases as the temperature correlated with the fuel viscosity decreases. The waveform is corrected. However, the waveform of the current applied to the fuel injection valve (108) may be corrected so that the fuel injection amount decreases as the measured or estimated fuel viscosity increases.

  Each of the above-described configurations, functions, processing units, and the like may be realized by hardware, for example, by designing a part or all of them with an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

101 ... Fuel injection control device
102 ... Fuel injection valve drive controller
102a ... Fuel injection valve pulse signal calculation block
102b ... Fuel injector drive waveform command block
102c… Correction parameter input
103… Power supply fuse
104… Power relay
105… Drive IC
106… High voltage generator
107a ... Fuel injection valve drive (Hi)
107b ... Fuel injection valve drive (Lo)
108 ... Fuel injection valve
109… Battery voltage
110… High voltage

Claims (4)

A booster that boosts a first voltage supplied from a battery and generates a second voltage higher than the first voltage;
A switch that switches a voltage applied to an injector that directly injects fuel into a combustion chamber of the engine to the first voltage or the second voltage, and turns on / off a current flowing through the injector;
A half lift control unit that controls the switch so that the injector is closed before the injector is fully opened according to the operating state of the engine to complete the fuel injection;
A current waveform correction unit that corrects a waveform of a current applied to the injector so that an injection amount of the fuel decreases as the viscosity of the fuel increases;
The current waveform correction unit is
The peak current value indicating the maximum value of the current flowing through the injector while the second voltage is applied to the injector, and the current flowing through the injector after applying the second voltage reaches the peak current value A fuel that reduces at least one of a peak current arrival time indicating a time until completion and a holding current value indicating a current value for holding the valve opening flowing in the injector by switching the first voltage. An injection control device,
A determination unit for determining whether or not the half lift control unit is operating;
The current waveform correction unit is
Only when it is determined that the half lift control unit is operating, the waveform of the current applied to the injector is corrected ,
The half lift control unit
The valve is opened by energizing the injector with the second voltage,
Before the injector is fully opened, the power to the injector is cut off, and the valve behavior is set to a half lift state.
A fuel injection control device for an internal combustion engine , wherein the lift amount of a half lift is adjusted according to a length of a period during which the injector is energized with the first voltage after the energization to the injector is interrupted . A fuel injection control device for an internal combustion engine according to claim 1,
The current waveform correction unit is
A fuel injection control device for an internal combustion engine, wherein a waveform of a current applied to the injector is corrected so that an injection amount of the fuel decreases as a temperature correlated with the viscosity of the fuel decreases. A fuel injection control device for an internal combustion engine according to claim 2 ,
The temperature is
A fuel injection control device for an internal combustion engine, characterized by being a temperature of cooling water, a temperature of lubricating oil, or a temperature of fuel. A fuel injection control device for an internal combustion engine according to claim 1,
The half lift control unit
After switching the voltage applied to the injector to the second voltage and turning on the current flowing through the injector, the current flowing through the injector is set to 0, and the voltage applied to the injector is then set to the first voltage. A fuel injection control device for an internal combustion engine, wherein the switch is controlled so as to switch on and off a current flowing through the injector.

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