Fuel injection control device

Abstract

In the fuel injection control device of the present invention, when the injection quantity instruction value of any split injection in multiple split injections is located in an area outside the allowable range of injection quantity deviation, the control unit of the fuel injection control device changes the injection quantity instruction value in an increasing direction (minimum value) or a decreasing direction (maximum value) based on a pre-set change reference, so that the injection quantity instruction value of the corresponding split injection is within the area within the allowable range of injection quantity deviation, and changes the injection quantity instruction values ​​of other split injections so that the total injection quantity of the multiple split injections does not change.

Description

Technical Field

[0001] The present invention relates to a fuel injection control device. Background Art

[0002] In recent years, internal combustion engines have been demanded to achieve both lower fuel consumption and higher output. One means of achieving this goal is to expand the dynamic range of fuel injection valves. This expansion requires improving dynamic flow characteristics while maintaining conventional static flow characteristics. One known method for improving these dynamic flow characteristics is to reduce the minimum injection quantity through partial lift control.

[0003] For example, Patent Document 1 discloses a control device that detects individual variation information for fuel injection valves and, based on this information, varies the drive current used to control the energization of the fuel injection valves for each fuel injection valve. Based on this information, the control device determines whether the peak current of the drive current common to all fuel injection valves installed in an internal combustion engine is excessive or insufficient, and optimizes the valve opening force by reducing or increasing the drive current. This maintains the linearity of fuel injection characteristics and reduces injection quantity variations caused by component variations between fuel injection valves.

[0004] However, the fuel injection valve control device disclosed in Patent Document 1 synchronizes the valve body movements of each fuel injection valve in the half-lift region before the valve body reaches the full-lift position, thereby reducing variations in injection quantity between each fuel injection valve. However, as the pressure of the supplied fuel (fuel pressure) increases, the minimum guaranteed current value that allows the valve to open increases. Therefore, at high fuel pressures, it may be difficult to perform current correction to reduce the peak current value.

[0005] Another method for reducing injection quantity variation among individual fuel injection valves involves detecting individual fuel injection valve variation information and adjusting the energization time of each fuel injection valve based on this information. Specifically, the characteristics of all fuel injection valves installed in the internal combustion engine are detected and compared onboard with those of a reference fuel injection valve. The energization time is then increased or decreased to determine whether it is excessive or insufficient. By controlling the valve opening time of each fuel injection valve in this manner, injection quantity variation caused by component variation can be reduced.

[0006] Therefore, the variable drive current method significantly reduces injection amount variation due to reduced valve body bounce, but current reduction may be difficult at higher fuel pressures. On the other hand, the variable energization time method, while unable to reduce valve body bounce itself, can reduce injection amount variation and is applicable to both low and high fuel pressures.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2018-109411 Summary of the Invention

[0010] Technical problem to be solved by the invention

[0011] However, this conventional method of reducing injection quantity variation for each fuel injection valve by varying the energization duration cannot mitigate valve bounce itself. Consequently, injection quantity variation increases in the bounce region immediately after the valve reaches full lift. Specifically, injection quantity variation increases when fuel is injected with corresponding injection quantities (or energization durations) between the partial lift control range, where energization is deactivated before the valve reaches full lift, and the full lift control range, where energization is deactivated after the valve reaches full lift. Consequently, when the required injection quantity for combustion falls within the bounce region, injecting fuel at the required injection quantity increases injection quantity variation.

[0012] The present invention has been made in view of the above-mentioned circumstances, and can prevent an increase in injection amount variation of fuel injection when the required injection amount is in a region where the injection amount variation is large.

[0013] Technical means for solving technical problems

[0014] In order to solve the above problems, a fuel injection control device of one embodiment of the present invention is applied to an internal combustion engine assembled with multiple fuel injection valves having coils for energization. In each combustion injection valve, the amount of fuel equivalent to the total injection amount required for one combustion is divided into multiple times for injection.

[0015] The above-mentioned fuel injection control device includes a control unit, which, when the injection quantity instruction value of any split injection among multiple split injections is located in an area outside the allowable range of injection quantity deviation, changes the injection quantity instruction value of the corresponding split injection in an increasing direction or a decreasing direction based on a pre-set change reference, so that the injection quantity instruction value is within the area within the allowable range of injection quantity deviation, and changes the injection quantity instruction values ​​of other split injections so that the total injection quantity of multiple split injections does not change.

[0016] Effects of the Invention

[0017] According to at least one aspect of the present invention, the injection quantity command value for a split injection that is outside the allowable injection quantity deviation range is changed so that the command value falls within the allowable injection quantity deviation range. This prevents the use of injection quantity command values ​​outside the allowable injection quantity deviation range, thereby preventing an increase in injection quantity deviations among the split injections. Furthermore, since the injection quantity command values ​​for the remaining split injections are changed, the total injection quantity of the multiple split injections remains unchanged. This maintains the total injection quantity while preventing an increase in injection quantity deviations among the total injection quantity.

[0018] Technical problems, structures, and effects other than those described above will become more apparent through the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an overall configuration diagram showing a basic configuration example of an internal combustion engine system equipped with the fuel injection control device according to the first embodiment of the present invention.

[0020] Figure 2 This is a block diagram showing an example of the internal structure of the fuel injection control device according to the first embodiment of the present invention.

[0021] Figure 3 It shows Figure 2 The circuit diagram of the fuel injection drive unit shown is an example of the structure.

[0022] Figure 4 yes Figure 1 A cross-sectional view of a fuel injection valve is shown.

[0023] Figure 5 It is an explanation Figure 1 The timing chart of the fuel injection valve driving method shown is shown.

[0024] Figure 6 yes Figure 1 The graph shown is a graph of the relationship between the fuel injection pulse width and the fuel injection amount of the fuel injection valve.

[0025] Figure 7 This is a graph showing the relationship between the valve closing completion time and the pulse width correction amount, used when performing injection pulse width correction.

[0026] Figure 8 It is an explanation Figure 1 The graph shown is a graph of detecting valve body operation time using drive voltage in a fuel injection valve.

[0027] Figure 9 This is a graph illustrating a region where the injection amount variation of the fuel injection valve becomes large.

[0028] Figure 10This is a diagram for explaining an example of limiting the fuel injection pulse width using the minimum value within the full lift control range.

[0029] Figure 11 This is a diagram for explaining an example of limiting the fuel injection pulse width using the maximum value within the partial lift control range.

[0030] Figure 12 This is a time chart showing an example of a process for limiting the fuel injection pulse width of the injection close to the ignition timing.

[0031] Figure 13 1 is a timing chart showing an example of a process of limiting the fuel injection pulse width of an injection with a short injection interval.

[0032] Figure 14 This is a timing chart explaining an example of a process for limiting the fuel injection pulse width of an injection with a small drive voltage or drive current. DETAILED DESCRIPTION

[0033] Hereinafter, examples of the mode for implementing the present invention will be described with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same function or structure are denoted by the same reference numerals, and repeated description will be omitted.

[0034] <Implementation Method 1>

[0035] [Internal combustion engine system]

[0036] First, the configuration of an internal combustion engine system equipped with the fuel injection control device according to the first embodiment of the present invention will be described. Figure 1 This is an overall configuration diagram showing a basic configuration example of an internal combustion engine system equipped with the fuel injection control device according to the first embodiment of the present invention.

[0037] Figure 1 The illustrated internal combustion engine (engine) 101 is a four-cycle engine that repeats the four strokes of intake, compression, combustion (expansion), and exhaust, and is, for example, a multi-cylinder engine having four cylinders (working cylinders). The number of cylinders in internal combustion engine 101 is not limited to four, but may be any number, such as six or eight.

[0038] Internal combustion engine 101 includes pistons 102, intake valves 103, and exhaust valves 104. Intake air (intake air) entering internal combustion engine 101 passes through an air flow meter (AFM) 120 for detecting the amount of air flowing in, and its flow rate is regulated by throttle valve 119. Air passing through throttle valve 119 is drawn into collector 115, which serves as a branching point, and is then supplied to combustion chamber 121 of each cylinder via intake pipe 110 and intake valve 103 provided in each cylinder (working cylinder).

[0039] On the other hand, fuel is supplied from the fuel tank 123 to the high-pressure fuel pump 125 by the low-pressure fuel pump 124, and is raised to a pressure required for fuel injection by the high-pressure fuel pump 125. Specifically, the high-pressure fuel pump 125 uses power transmitted from an exhaust camshaft (not shown) of an exhaust cam 128 to move a plunger provided in the high-pressure fuel pump 125 up and down, thereby pressurizing (boosting) the fuel in the high-pressure fuel pump 125.

[0040] A solenoid-driven on-off valve is installed at the intake port of the high-pressure fuel pump 125. The solenoid is connected to a fuel injection control unit 127 housed within the ECU (Engine Control Unit) 109, an electronic control unit. Based on control commands from the ECU 109, the fuel injection control unit 127 controls the solenoid and drives the on-off valve to achieve a desired pressure for the fuel discharged from the high-pressure fuel pump 125 (hereinafter referred to as "fuel pressure").

[0041] As an example, ECU 109 (fuel injection control device 127) includes a CPU 141, a memory 142, and an input / output interface (not shown). CPU 141 is a processor that performs computational processing. Memory 142 is a storage unit composed of non-volatile and / or volatile semiconductor memory, and stores, for example, a change reference for the fuel injection amount of split injection (hereinafter referred to as "split injection amount") used in the restriction process described later. A computer program for controlling the fuel injection valve 105 may also be stored in memory 142. In this case, CPU 141 reads and executes the computer program stored in memory 142, thereby implementing all or part of the functions of fuel injection control device 127. An ignition switch signal for instructing the internal combustion engine 101 to start (ignite) is input to ECU 109. For example, if CPU 141 detects that the ignition switch signal is on, it begins processing the fuel injection control computer program. Alternatively, another computational processing device such as an MPU (Micro Processing Unit) may be used in place of CPU 141.

[0042] The fuel, whose pressure is increased by the high-pressure fuel pump 125, is delivered to the fuel injection valve 105 via the high-pressure fuel pipe 129. The fuel injection valve 105 injects the fuel directly into the combustion chamber 121 based on a command from the fuel injection control device 127. The fuel injection valve 105 is an electromagnetic valve. When a driving current is supplied (energized) to an electromagnetic coil (described later), the valve body is actuated to perform fuel injection.

[0043] Furthermore, the internal combustion engine 101 is provided with a fuel pressure sensor 126 for measuring the pressure of the fuel in the high-pressure fuel pipe 129. Based on the measurement results of the fuel pressure sensor 126, the ECU 109 transmits a control command to the fuel injection control device 127 for adjusting the fuel pressure in the high-pressure fuel pipe 129 to a desired pressure. In other words, the ECU 109 performs so-called feedback control to adjust the fuel pressure in the high-pressure fuel pipe 129 to the desired pressure.

[0044] Furthermore, each combustion chamber 121 of the internal combustion engine 101 is provided with a spark plug 106, an ignition coil 107, and a water temperature sensor 108. The spark plug 106 exposes its electrode portion within the combustion chamber 121 and ignites the mixture of intake air and fuel within the combustion chamber 121 through discharge. The ignition coil 107 generates a high voltage for discharging the spark plug 106. The water temperature sensor 108 measures the temperature of the cooling water used to cool the cylinders of the internal combustion engine 101.

[0045] The ECU 109 controls the energization of the ignition coil 107 and the ignition of the spark plug 106. A mixture of intake air and fuel in the combustion chamber 121 is combusted by a spark from the spark plug 106, and the pressure generated thereby pushes the piston 102 downward.

[0046] Exhaust gas generated by combustion is discharged into an exhaust pipe 111 via an exhaust valve 104. Furthermore, a three-way catalytic converter 112 and an oxygen sensor 113 are provided in the exhaust pipe 111. The three-way catalytic converter 112 purifies harmful substances such as nitrogen oxides (NOx) contained in the exhaust gas. The oxygen sensor 113 detects the oxygen concentration contained in the exhaust gas and outputs the detection result to the ECU 109. The ECU 109 performs feedback control based on the detection result of the oxygen sensor 113 so that the fuel injection amount supplied from the fuel injection valve 105 reaches the target air-fuel ratio.

[0047] Furthermore, a crankshaft 131 is connected to the piston 102 via a connecting rod 132. The reciprocating motion of the piston 102 is then converted into rotational motion by the crankshaft 131. A crank angle sensor 116 is mounted on the crankshaft 131. The crank angle sensor 116 detects the rotation and phase of the crankshaft 131 and outputs the detection result to the ECU 109. The ECU 109 can detect the rotation speed of the internal combustion engine 101 based on the output of the crank angle sensor 116.

[0048] Signals from a crank angle sensor 116 , an air flow meter 120 , an oxygen sensor 113 , an accelerator opening sensor 122 indicating the opening of an accelerator operated by a driver, a fuel pressure sensor 126 , and the like are input to the ECU 109 .

[0049] The ECU 109 calculates the required torque of the internal combustion engine 101 based on the signal provided by the accelerator opening sensor 122, determines whether it is in an idle state, etc. In addition, the ECU 109 calculates the amount of intake air required by the internal combustion engine 101 based on the required torque, etc., and outputs an opening signal corresponding to the calculated amount to the throttle valve 119.

[0050] The ECU 109 also includes a rotation speed detection unit that calculates the rotation speed of the internal combustion engine 101 (hereinafter also referred to as the engine speed) based on a signal provided by the crank angle sensor 116. Furthermore, the ECU 109 includes a warm-up determination unit that determines whether the three-way catalyst 112 is in a warm-up state based on the temperature of the cooling water obtained from the water temperature sensor 108 and the time elapsed since the start of the internal combustion engine 101.

[0051] The fuel injection control device 127 calculates the fuel amount corresponding to the intake air amount and outputs a corresponding fuel injection signal to the fuel injection valve 105. The fuel injection control device 127 also outputs an energization signal to the ignition coil 107 and an ignition signal to the spark plug 106.

[0052] [Structure of the fuel injection control device]

[0053] Next, use Figure 2 and Figure 3 illustrate Figure 1 The structure of the fuel injection control device 127 is shown.

[0054] Figure 2 1 is a block diagram showing an example of the internal configuration of the fuel injection control device 127 .

[0055] Figure 3 It shows Figure 2 The circuit diagram of the fuel injection drive units 207a and 207b shown in FIG.

[0056] like Figure 2 As shown, the fuel injection control device 127 includes an engine state detection unit 214, a split injection command unit 201, a fuel injection pulse signal calculation unit 202, a fuel injection drive waveform command unit 203, and a driver IC 208 as a fuel injection control unit. The fuel injection control device 127 also includes a high voltage generator (boosting device) 206, fuel injection drive units 207a and 207b, a valve body operation time detection unit 211, and a fuel injection pulse signal correction amount calculation unit 212.

[0057] The engine state detection unit 214 collects and provides various information such as the engine speed, intake air volume, cooling water temperature, fuel pressure, and fault status of the internal combustion engine 101 .

[0058] The split injection command unit 201 determines whether to execute split injection based on various information obtained from the engine state detection unit 214 and the operating state or operating scenario of the internal combustion engine 101 (e.g., urban driving, high-speed (constant speed) driving, etc.). If it is determined that split injection control is permitted, the split injection command unit 201 calculates the number of split injections, the split ratio (ratio) of the fuel injection amount, the respective injection start timings, the requested total injection amount, etc., and outputs the split injection command including the calculated various information to the fuel injection pulse signal calculation unit 202.

[0059] The fuel injection pulse signal calculation unit 202 (fuel injection pulse output unit) calculates a fuel injection pulse signal for achieving fuel injection at the requested total injection amount based on various information including fuel pressure obtained from the engine state detection unit 214, as well as various information such as the number of split injections, the split ratio of the fuel injection amount, and the requested total injection amount obtained from the split injection command unit 201. The fuel injection pulse signal calculation unit 202 includes a split injection amount calculation unit 221, a fuel injection pulse signal command unit 222, and a fuel injection pulse signal limiter 223.

[0060] Split injection quantity calculation unit 221 receives split injection commands from split injection command unit 201 and calculates the fuel injection quantity (injection quantity command value) for each split injection. In split injection, the total injection quantity required for combustion in one combustion cycle is divided into multiple fuel injections according to a split ratio. Therefore, the injection pulse width calculation also requires the number of splits. For example, if fuel injection is performed in two equal parts during one combustion cycle, the injection quantities obtained by multiplying the required total injection quantity by the split ratio of 0.5 are the first and second split injection quantities. Split injection quantity calculation unit 221 calculates the fuel injection quantity for each split injection in this manner.

[0061] Based on the fuel injection amounts for each split injection calculated by the split injection amount calculation unit 221 and the various information described above, the fuel injection pulse signal command unit 222 calculates an injection pulse width (energization period) that defines the fuel injection period of the fuel injection valve 105 for injecting fuel at the requested total injection amount. The fuel injection pulse signal command unit 222 then outputs a fuel injection pulse signal corresponding to the calculated injection pulse width to the driver IC 208 in accordance with the injection start timing. Naturally, when split injection control is not executed, only one fuel injection is performed per combustion cycle, and the injection pulse width is the injection pulse width calculated based on the requested total injection amount.

[0062] When the injection amount deviation of the calculated divided injection amount (injection amount command value) is outside the allowable range (in Figure 9In the case where the calculated split injection amount is outside the allowable range of the injection amount deviation), the fuel injection pulse signal limiting unit 223 limits (changes) the corresponding split injection amount based on a pre-set change reference so as not to use the fuel injection amount whose injection amount deviation is outside the allowable range. In the present embodiment, such a process of limiting the split injection amount is referred to as "limitation processing". In the limitation processing, when the calculated split injection amount is outside the allowable range of the injection amount deviation, the split injection amount is changed to another split injection amount within the allowable range of the injection amount deviation. For details of the limitation processing, see Figure 9 This will be described in detail later.

[0063] The fuel injection drive waveform command unit 203 calculates a command value for the drive current provided to open and maintain the fuel injection valve 105 based on various information such as the fuel pressure obtained from the engine state detection unit 214, and outputs the command value for the drive current to the driver IC 208. In this embodiment, the command value for the drive current is a current value common to all cylinders, but is not limited to this.

[0064] The valve operating time detection unit 211 detects the valve closing time (valve operating time) of the fuel injection valve 105, that is, the time from the cessation of power supply to the solenoid 407 (coil) to the completion of the valve closing operation of the valve body 402, and outputs this time to the fuel injection pulse signal correction amount calculation unit 212. This valve operating time is information on individual differences between each fuel injection valve 105 installed in the internal combustion engine 101.

[0065] The fuel injection pulse signal correction amount calculation unit 212 (an example of a correction amount calculation unit) calculates a correction amount for the injection pulse width (energization time) of the fuel injection valve 105 for each cylinder based on the valve operation time detected by the valve operation time detection unit 211. The injection pulse width calculated by the fuel injection pulse signal calculation unit 202 is determined based on the fuel injection amount (injection amount command value) and the characteristics of a reference fuel injection valve (e.g., an intermediate product with design deviation). Therefore, the fuel injection pulse signal calculation unit 202 adds the calculated injection pulse width to the correction amount for the injection pulse width for each cylinder (fuel injection valve 105) calculated by the fuel injection pulse signal correction amount calculation unit 212, and outputs the result to the driver IC 208.

[0066] Battery voltage 209 is supplied to high-voltage generator 206 via fuse 204 and relay 205. Based on battery voltage 209, high-voltage generator 206 generates the higher power supply voltage (boosted voltage) required to open electromagnetic solenoid fuel injection valve 105. Hereinafter, the power supply voltage will be referred to as high voltage 210. The power supply for fuel injection valve 105 consists of two systems: high voltage 210, which is used to ensure the valve opening force, and battery voltage 209, which is used to maintain the valve open and prevent it from closing after opening.

[0067] Fuel injection driver 207a (switching unit) is provided on the upstream side (power supply side, high side) of fuel injection valve 105, and supplies high voltage 210 required to open fuel injection valve 105 to fuel injection valve 105. Furthermore, after fuel injection valve 105 is opened, fuel injection driver 207a supplies battery voltage 209 required to maintain the open state of fuel injection valve 105 to fuel injection valve 105.

[0068] like Figure 3 As shown, the fuel injection driver 207a includes diodes 301 and 302, a high-voltage side switching element 303, and a low-voltage side switching element 304. The fuel injection driver 207a passes the high voltage 210 supplied from the high voltage generator 206 through the diode 301 provided to prevent current backflow, and supplies the high voltage 210 to the fuel injection valve 105 using the high-voltage side switching element 303.

[0069] The fuel injection driver 207 a passes the battery voltage 209 supplied via the relay 205 through a diode 302 provided to prevent current backflow, and supplies the battery voltage 209 to the fuel injection valve 105 using the low-voltage side switching element 304 .

[0070] Fuel injection driver 207b (switching unit) is provided on the downstream side (ground side and low side) of fuel injection valve 105 and includes switching element 305 and shunt resistor 306. By turning on switching element 305, fuel injection driver 207b applies power supplied from upstream fuel injection driver 207a to fuel injection valve 105. Fuel injection driver 207b also detects the current consumed by fuel injection valve 105 via shunt resistor 306.

[0071] Figure 2The illustrated driver IC 208 controls the fuel injection driver units 207a and 207b based on the injection pulse width calculated by the fuel injection pulse signal calculation unit 202 and the drive current waveform (drive current curve) calculated by the fuel injection drive waveform command unit 203. Specifically, the driver IC 208 controls the high voltage 210 and battery voltage 209 applied to the fuel injection valve 105, thereby controlling the drive current supplied to the fuel injection valve 105.

[0072] Furthermore, diode 309 is forward-connected between the downstream side of solenoid 407 and high voltage generator 206, and diode 308 is forward-connected between shunt resistor 306 and the upstream side of solenoid 407. When high-voltage-side switching element 303, low-voltage-side switching element 304, and switching element 305 are off, diodes 308 and 309 are energized by the back electromotive force generated in solenoid 407 of fuel injection valve 105. This feeds current back to high voltage generator 206, rapidly reducing the drive current supplied to solenoid 407. At this point, a voltage with reverse polarity, for example, equivalent to high voltage 210, is generated between the terminals of solenoid 407 as the back electromotive force.

[0073] [Structure of the fuel injection valve]

[0074] Next, refer to Figure 4 The structure of the fuel injection valve 105 will be described.

[0075] Figure 4 It is a cross-sectional view of the fuel injection valve 105 .

[0076] Fuel injection valve 105 is an electromagnetic fuel injection valve comprising a normally closed solenoid valve. Fuel injection valve 105 comprises a housing 401 forming an outer shell, a valve body 402 disposed within housing 401, a movable core 403, and a fixed core 404. Housing 401 is formed with a valve seat 405 and an injection hole 406 communicating with valve seat 405.

[0077] The valve body 402 is formed into a generally rod-like shape, with a tip end 402a at one end formed into a generally conical shape. The tip end 402a of the valve body 402 faces the valve seat 405 of the housing 401. When the tip end 402a of the valve body 402 contacts the valve seat 405, the fuel injection valve 105 closes, and fuel is no longer injected from the injection hole 406. Hereinafter, the direction in which the tip end 402a of the valve body 402 approaches the valve seat 405 is referred to as the valve closing direction, and the direction in which the tip end 402a of the valve body 402 moves away from the valve seat 405 is referred to as the valve opening direction.

[0078] The fixed core 404 is formed into a cylindrical shape and is fixed to the end of the housing 401 opposite the valve seat 405. The other end (rear end) of the valve body 402 is inserted into the cylindrical hole of the fixed core 404. In addition, the solenoid 407 is arranged inside the fixed core 404 so as to surround the other end (rear end) of the valve body 402.

[0079] A clutch lever spring 408 is disposed in the cylindrical hole of the fixed core 404 to bias the valve body 402 in the valve closing direction. One end of the clutch lever spring 408 abuts against the rear end 402b of the valve body 402, while the other end of the clutch lever spring 408 abuts against the housing 401.

[0080] The movable core 403 is disposed between the fixed core 404 and the valve seat 405 and has a circular through-hole 403a through which the valve body 402 passes. Furthermore, the diameter of the rear end portion 402b of the valve body 402 is larger than the through-hole 403a of the movable core 403. Therefore, the periphery of the through-hole 403a in the movable core 403 and the periphery of the rear end portion 402b of the valve body 402 are opposite to each other.

[0081] A zero-length spring 409 is disposed between the movable core 403 and the housing 401. The zero-length spring 409 biases the movable core 403 in the valve-opening direction. The bias of the zero-length spring 409 positions the movable core 403 at its initial position between the fixed core 404 and the valve seat 405.

[0082] The interior of housing 401 is filled with fuel. When no current flows through solenoid 407, clutch lever spring 408 biases valve body 402 in the valve-closing direction, overcoming the spring load (elastic force) of zero-length spring 409 and pushing valve body 402 in the valve-closing direction. As a result, the front end 402a of valve body 402 contacts valve seat 405, closing injection port 406.

[0083] When current flows through solenoid 407, magnetic flux is generated between fixed core 404 and movable core 403, and a magnetic attraction force acts on movable core 403. As a result, movable core 403 is attracted to fixed core 404 (solenoid 407), and movable core 403 abuts against rear end 402b of valve body 402. As a result, valve body 402 and movable core 403 move in the valve opening direction in conjunction with each other.

[0084] When the valve body 402 moves in the valve-opening direction, the front end 402a of the valve body 402 separates from the valve seat 405, and the injection hole 406, which was previously blocked by the valve body 402, is opened, and fuel is injected. Furthermore, after the fuel is injected, the movable core 403 returns to its initial position due to the balance between the clutch lever spring 408 and the zero-length spring 409.

[0085] [Method of driving the fuel injection valve]

[0086] Next, refer to Figure 5 A method of driving the fuel injection valve 105 will be described.

[0087] Figure 5 It is a timing chart for explaining a method of driving the fuel injection valve 105 . Figure 5 1 shows an example of an injection pulse, a driving voltage, a driving current, and a displacement amount (valve displacement) of the valve body 402 when fuel is injected from the fuel injection valve 105 in a time series. The horizontal axis represents time.

[0088] When driving the fuel injection valve 105, a current setting value (described later) is pre-set based on the characteristics of the fuel injection valve 105. The injection quantity characteristics of the fuel injection valve 105 based on the current setting value are pre-stored in a memory 142 (e.g., RAM) provided within the ECU 109. The fuel injection control device 127 calculates the injection pulse of the fuel injection valve 105 based on the operating state of the internal combustion engine 101 and the injection quantity characteristics of the fuel injection valve 105.

[0089] exist Figure 5 At the time T500 to T501 shown in FIG. 1 , the fuel injection pulse signal calculation unit 202 (see FIG. Figure 2 ) is in the off state. Consequently, fuel injection driver units 207a and 207b are in the off state, and no drive current flows through fuel injection valve 105. Consequently, the spring load of clutch lever spring 408 of fuel injection valve 105 biases valve body 402 toward the valve closing direction, causing the front end 402a of valve body 402 to abut against valve seat 405, closing injection hole 406 and preventing fuel from being injected.

[0090] Next, at time T501, the injection pulse is turned on, and the fuel injection driver 207a and the fuel injection driver 207b are turned on. As a result, high voltage 210 is applied to the solenoid 407, causing a drive current to flow through the solenoid 407. The flow of the drive current through the solenoid 407 generates a magnetic flux between the fixed core 404 and the movable core 403, and a magnetic attraction force acts on the movable core 403.

[0091] When magnetic attraction acts on movable core 403, it begins to move toward the valve opening direction (times T501 to T502). After movable core 403 has moved a predetermined distance, it and valve element 402 begin to move together (time T502), causing valve element 402 to separate from valve seat 405, thereby opening fuel injection valve 105. As a result, fuel within housing 401 is ejected from injection hole 406.

[0092] The valve body 402 and the movable core 403 move together until the movable core 403 collides with the fixed core 404. Then, when the movable core 403 collides with the fixed core 404, the movable core 403 is rebounded by the fixed core 404, causing the valve body 402 to move further toward the valve opening direction. Thereafter, when the spring load of the clutch lever spring 408 and the force applied by the fuel pressure exceed the magnetic attraction, the valve body 402 begins to move toward the valve closing direction (hereinafter referred to as the bouncing action). This bouncing action of the valve body 402 disrupts the flow rate of fuel injected from the injection hole 406.

[0093] Therefore, before the movable core 403 collides with the fixed core 404 (time T503), that is, when the drive current reaches the peak current Ip, the switching elements 303 and 304 of the fuel injection drive parts 207a and 207b are turned off, reducing the drive current flowing through the solenoid 407.

[0094] Then, after the movable core 403 collides with the fixed core 404, from time T504 until time T505, when the injection pulse decreases, the fuel injection driver 207b remains in the on state, while the fuel injection driver 207a is intermittently in the on state. Specifically, by performing PMW (Pulse Width Modulation) control on the fuel injection driver 207a, the drive voltage applied to the solenoid 407 is intermittently set to the battery voltage 209, thereby keeping the drive current flowing through the solenoid 407 within a specified range. This generates the magnetic attraction force required to attract the movable core 403 to the fixed core 404.

[0095] At time T506, the injection pulse is turned off. Consequently, both fuel injection driver units 207a and 207b are turned off, reducing the drive voltage applied to solenoid 407 and the drive current flowing through solenoid 407. Consequently, the magnetic flux generated between fixed core 404 and movable core 403 gradually disappears, and the magnetic attraction force acting on movable core 403 disappears.

[0096] When the magnetic attraction acting on movable core 403 disappears, the spring load of clutch lever spring 408 and the pressing force generated by fuel pressure (fuel pressure) push valve body 402 back toward the valve closing direction after a predetermined delay. Then, at time T506, valve body 402 returns to its original position. In other words, the front end 402a of valve body 402 abuts against valve seat 405, closing fuel injection valve 105. As a result, fuel is no longer injected from injection hole 406.

[0097] Starting from time T505 when the injection pulse is in the off state, in order to quickly eliminate the residual magnetism in the fuel injection valve 105 and close the valve body 402 as soon as possible, the high voltage 210 is supplied in the opposite direction to when the fuel injection valve 105 is driven.

[0098] [Injection quantity characteristics]

[0099] Next, use Figure 6 Instructions for use Figure 5 The injection quantity characteristics when the driving current is described in detail in .

[0100] Figure 6 This graph shows the relationship between the fuel injection pulse width and the fuel injection amount of the fuel injection valve 105, with the injection pulse width on the horizontal axis and the fuel injection amount per hour on the vertical axis. The fuel injection valve 105P having the injection amount characteristic 610 shown by the solid line is used as the reference product. The injection amount characteristic 611 shown by the dotted line indicates that the force acting on the clutch lever spring 408 is less than that of the reference product fuel injection valve 105W, while the injection amount characteristic 612 shown by the dashed line indicates that the force acting on the clutch lever spring 408 is greater than that of the reference product fuel injection valve 105S.

[0101] like Figure 6 As shown, in the case of a fuel injection valve having injection quantity characteristic 610, from time T502 when valve body 402 begins to open to time T601 when valve body 402 reaches full lift, the lift of valve body 402 increases based on the supply time of the peak current obtained by applying a high voltage, thereby increasing the fuel injection quantity. The slope of the fuel injection quantity during this period (the rate of increase in the fuel injection quantity from time T502 to time T601) is determined by the valve opening speed of valve body 402. As described above, the peak current is supplied by high voltage 210, so the slope of the fuel injection quantity is steep.

[0102] Subsequently, the movable core 403 collides with the fixed core 404, causing the valve body 402 to begin bouncing, significantly disturbing the fuel injection amount (from time T601 to time T602). This bouncing behavior can occur due to differences in the characteristics of individual fuel injection valves, or when the drive current is too large relative to the spring load of the clutch lever spring 408 or the pressing force generated by the fuel pressure.

[0103] The valve body 402 maintains the full lift position after the timing T602 at which the bouncing action converges, and therefore the fuel injection amount has an increasing characteristic with a slope proportional to the length of the injection pulse.

[0104] Injection quantity characteristic 611 of fuel injection valve 105W, compared to fuel injection valve 105P having injection quantity characteristic 610, the injection quantity increase rate during valve opening is higher and the pulsation is greater. Furthermore, after time T602, when the pulsation converges, the injection quantity in injection quantity characteristic 611 also increases relative to injection quantity characteristic 610. This is because, by driving each fuel injection valve with the same drive current, fuel injection valve 105W, which has a weaker spring load on clutch lever spring 408, has a faster valve opening speed, resulting in a higher injection quantity increase rate during valve opening, while its valve closing speed slows down after de-energization. Consequently, injection quantity characteristic 611 exhibits a characteristic that is biased toward a higher injection quantity relative to injection quantity characteristic 610.

[0105] Injection quantity characteristic 612 of fuel injection valve 105S exhibits characteristics opposite to injection quantity characteristic 611. Compared to fuel injection valve 105P, which exhibits injection quantity characteristic 610, the injection quantity increase rate during valve opening is lower and the pulsation is smaller. Furthermore, after time T602, when the pulsation converges, the injection quantity in injection quantity characteristic 612 also decreases relative to injection quantity characteristic 610. This is because, when each fuel injection valve is driven with the same drive current, fuel injection valve 105S, which has a stronger spring load on clutch lever spring 408, has a slower valve opening speed, resulting in a lower injection quantity increase rate during valve opening. However, after de-energization, the valve closing speed increases. Consequently, injection quantity characteristic 612 exhibits a characteristic that shifts toward a lower injection quantity relative to injection quantity characteristic 610.

[0106] For the reasons described above, driving multiple fuel injection valves with a common drive current and injection pulse width can lead to variations in injection quantity between the individual fuel injection valves. Specifically, the injection pulse width corresponding to the requested injection quantity calculated by engine state detection unit 214 is calculated using the injection quantity characteristics of fuel injection valve 105P. This injection quantity characteristic of fuel injection valve 105P serves as a reference for previously measured deviation intermediate products. Therefore, in order to reduce variations in injection quantity between the individual fuel injection valves, the injection pulse width of each fuel injection valve must be changed.

[0107] As described above, when injecting fuel at a certain required injection amount, the injection amount increases when fuel injection valve 105W, which has a smaller spring load on clutch lever spring 408, is driven with an injection pulse width calculated based on injection amount characteristic 610. On the other hand, when fuel injection valve 105S, which has a larger spring load on clutch lever spring 408, is driven with an injection pulse width calculated based on injection amount characteristic 610, the injection amount decreases.

[0108] In other words, in order to match the injection amount 630 of each fuel injection valve to the required injection amount, the injection pulse width (injection pulse width 621) of the fuel injection valve 105W having a weak spring load on the clutch lever spring 408 must be shortened relative to the injection pulse width 620 of the reference product (e.g., a product with an intermediate deviation). Furthermore, the injection pulse width (injection pulse width 622) of the fuel injection valve 105S having a strong spring load on the clutch lever spring 408 must be lengthened relative to the injection pulse width 620 of the reference product.

[0109] Therefore, in this embodiment, the valve closing completion time, which serves as information on individual differences between each fuel injection valve, is detected, and the injection pulse width of each fuel injection valve is adjusted based on the valve closing completion time, thereby reducing injection quantity variations between each fuel injection valve. The relationship between the injection pulse width correction amount and the valve closing completion time is pre-measured and stored in memory 142. The injection pulse width is corrected by calculating the injection pulse width correction amount relative to the measured valve closing completion time.

[0110] [Relationship between valve closing completion time and injection pulse width correction amount]

[0111] Figure 7 This is a graph showing the relationship between the valve closing completion time and the pulse width correction amount, used when performing injection pulse width correction.

[0112] The valve closing completion time of multiple fuel injection valves 105 is measured in advance through experiments, and the injection pulse width correction amount is calculated based on the injection quantity characteristics of the fuel injection valve 105 measured at the valve closing completion time, so that the relationship 700 between the valve closing completion time and the injection pulse width correction amount can be calculated.

[0113] For example, if the spring load of clutch lever spring 408 is large, the valve closing completion time becomes shorter. Therefore, in the case of fuel injection valve 105S, the injection pulse width needs to be increased to meet the required injection amount. Therefore, the injection pulse width correction value 713 for valve closing completion time 703, which is shorter than the reference valve closing completion time 701, becomes positive. Conversely, if the spring load of clutch lever spring 408 is small, the valve closing completion time becomes longer. Therefore, in the case of fuel injection valve 105W, the injection pulse width needs to be shortened to meet the required injection amount. Therefore, the injection pulse width correction value 712 for valve closing completion time 702, which is longer than the reference valve closing completion time 701, becomes negative.

[0114] Relational expression 700 can be calculated by approximating data of valve closing completion times of a plurality of fuel injection valves 105 using a least square method or the like. Figure 11An approximate straight line for a given fuel injection amount is shown. By precalculating the approximate straight line for multiple fuel injection amounts, an injection pulse width tailored to the injection amount characteristics can be calculated. Furthermore, since injection amount characteristics vary not only with the solidity error of the fuel injection valve but also with fuel pressure, it is sufficient to calculate an injection pulse width correction relative to a reference injection pulse width for each specific fuel pressure.

[0115] Since the calculated relational expression 700 represents representative fuel pressure points, the injection pulse width correction amount for the actual fuel pressure (e.g., the fuel pressure measured by the fuel pressure sensor 126) can be calculated by calculating the correction amount for a representative fuel pressure point greater than the actual fuel pressure and the correction amount for a representative fuel pressure point less than the actual fuel pressure, and then performing linear interpolation between the two points. Similarly, the fuel injection amount can be calculated by linear interpolation between the two points.

[0116] Therefore, based on Figure 7 The valve closing completion time is calculated by the method shown, and the correction amount of the injection pulse width is calculated according to the relationship 700, and the correction amount is added to the injection pulse width calculated as a benchmark for the required injection amount, so that the injection pulse width corresponding to the individual differences of the fuel injection valve 105 can be calculated.

[0117] [Method for detecting valve action time]

[0118] Next, we will refer to Figure 8 A method for detecting the valve operation time of the fuel injection valve 105 executed by the valve operation time detection unit 211 will be described.

[0119] Figure 8 This is a graph for explaining detection of valve body operation time (valve closing time) using a driving voltage of the fuel injection valve 105 . Figure 8 The upper part shows the time variation of the driving voltage. Figure 8 The lower portion of represents the second-order differential value of the drive voltage. In addition, the valve closing time 801 is defined as the time elapsed from the time when the injection pulse is turned off (time T505) to the time when the valve closing is completed (time T506).

[0120] As described above, when valve body 402 of fuel injection valve 105 is opened, high voltage 210 is applied to solenoid 407, causing a relatively large drive current to flow, accelerating movable core 403 and valve body 402. Subsequently, high voltage 210 applied to solenoid 407 is cut off, and the drive current flowing through solenoid 407 is reduced to a specified value (e.g., a holding current).

[0121] When the fuel injection valve 105 is closed, the valve body 402 collides with the valve seat 405, causing the zero-length spring 409 to shift from extension to compression, reversing the direction of motion of the movable core 403. This causes a change in acceleration and, consequently, a change in the inductance of the solenoid 407. Specifically, when the fuel injection valve 105 is closed, the drive current flowing through the solenoid 407 is cut off, and a back electromotive force is applied to the solenoid 407. As the drive current converges, the back electromotive force gradually decreases. Consequently, as the back electromotive force decreases, the inductance of the solenoid 407 changes, creating an inflection point (inflection point 802) in the drive voltage.

[0122] The inflection point 802 of the driving voltage that occurs when the fuel injection valve 105 is closed is the valve closing timing of the fuel injection valve 105. Therefore, the valve closing timing 801 can be detected by measuring the time from the timing when the injection pulse is turned off (time T506) to the inflection point 802 of the driving voltage.

[0123] When the time series data of the driving voltage applied to the solenoid 407 is secondarily differentiated, the inflection point 802 appears as an extreme value 811 (maximum value or minimum value). Therefore, the inflection point 802 can be determined by detecting the extreme value of the time series data of the driving voltage.

[0124] Furthermore, when the S / N ratio of the drive voltage is low and the noise level is high, it becomes difficult to detect extreme values ​​based on the results of the second-order differentiation of the time series data of the drive voltage. Therefore, by applying a low-pass filter, etc. to the drive voltage and performing the second-order differentiation of the smoothed time series data, it is possible to detect the desired extreme value. Figure 8 The second-order differential value of the driving voltage shown in the lower section is obtained by filtering the time series data of the driving voltage and performing second-order differentiation on the smoothed time series data.

[0125] If the second-order differential is performed on the time series data of the drive voltage starting from the moment the ejection pulse is turned off (time T505), extreme values ​​may appear at the time of voltage switching (such as when back electromotive force is applied after the drive voltage is turned off). As a result, the inflection point caused by the acceleration change of the movable core 403 cannot be accurately determined.

[0126] Therefore, the time series data of the drive voltage for which the second-order differentiation is performed is preferably the time series data of the drive voltage after a certain time has passed since the ejection pulse was turned off (in other words, since the drive voltage was turned off or the drive current was turned off). In other words, the time series data of the drive voltage for which the second-order differentiation is performed is preferably the time series data of the drive voltage when the back electromotive force is applied after the drive voltage is turned off.

[0127] As described above, by adjusting the injection pulse width based on the individual differences between the fuel injection valves 105 used as the reference, it is possible to reduce injection quantity variation between each fuel injection valve (and between cylinders). This further reduces the minimum injection quantity within which injection quantity variation remains within the allowable range. However, as described above, while overall injection quantity variation is reduced, injection quantity variation is relatively large in the bounce region immediately after the valve body 402 reaches the full lift position. This is because the amount of overshoot of the valve body 402 from the full lift position varies due to variations in the spring load of the clutch lever spring 408 of the fuel injection valve 105.

[0128] [Injection quantity characteristics and injection quantity deviation]

[0129] Figure 9 Graph showing a region where the injection amount deviation of the fuel injection valve 105 becomes large. Figure 9 In the middle, the upper section shows the injection amount characteristics, and the lower section shows the injection amount deviation.

[0130] exist Figure 9 In the rare injection range 911 of the injection quantity characteristic 901 shown, if the injection pulse width (energization time) becomes longer and fuel injection starts soon, a very large injection quantity deviation 921 occurs. This is because the injection quantity itself is extremely small, so the deviation becomes proportional to the injection quantity.

[0131] Furthermore, as the energization time increases, the injection amount deviation 921 becomes smaller than the allowable deviation upper limit 922. This can reduce the injection amount deviation by changing the injection pulse width according to the individual differences of each fuel injection valve 105 as described above, and the partial lift control range 912 before the valve body 402 of the fuel injection valve 105 reaches the full lift position can also be used for fuel injection.

[0132] Thereafter, as the energization time increases, the power of valve body 402 increases, causing valve body 402 to continue rising even after reaching full lift. Ultimately, valve body 402 is lowered by the force of clutch lever spring 408. In this bounce region 913 of valve body 402, injection amount deviation 921 again exceeds allowable deviation upper limit 922.

[0133] After the valve body 402 stabilizes at the full lift position, the injection amount deviation 921 again becomes smaller than the allowable deviation upper limit 922. This is because as the energization time increases, the injection amount increases, and the ratio of the deviation to the injection amount decreases.

[0134] As described above, a jump region 913 exists between the partial lift control range 912, where energization is stopped before the valve body 402 of the fuel injection valve 105 reaches the full lift position, and the full lift control range 914, where injection amount variation increases. Consequently, the commanded injection amount (or injection pulse width) cannot be continuously changed from a low injection amount to a high injection amount (or from a short pulse width to a long pulse width) between the partial lift control range 912 and the full lift control range 914. Furthermore, if the commanded injection amount falls within the jump region 913, injection amount variation increases, potentially leading to poor combustion and potentially deteriorating exhaust performance.

[0135] The jump region 913 is a region in which the injection amount deviation in the injection amount characteristic 901 is outside the allowable range (exceeding the allowable deviation upper limit 922). Specifically, the region in which the split injection amount is outside the allowable injection amount deviation range refers to a region in which the injection amount command value (required split injection amount) for the split injection exceeds the maximum injection amount value Qpmax (maximum value) within the partial lift control range, where energization is stopped before the valve body 402 of the fuel injection valve 105 reaches the fully open position (full lift position), and is smaller than the minimum injection amount value Qfmin (minimum value) within the full lift control range, where energization is stopped after the valve body 402 of the fuel injection valve 105 reaches the fully open full lift position. Hereinafter, the maximum injection amount value Qpmax will be referred to as "maximum value Qpmax," and the minimum injection amount value Qfmin will be referred to as "minimum value Qfmin."

[0136] Therefore, when the divided required injection amount is within the jump region 913, the fuel injection control device 127 changes the required injection amount to the maximum value Qpmax within the partial lift control range or the minimum value Qfmin within the full lift control range, and sets the energization time to "TIpmax" or "TIfmin." This allows the injection amount deviation to be set below the allowable deviation upper limit 922.

[0137] However, changing the required injection quantity to the maximum value Qpmax within the partial lift control range or the minimum value Qfmin within the full lift control range can avoid an increase in injection quantity variation, but the total injection quantity injected during a single combustion cycle changes. This alters the air-fuel ratio of the mixture, resulting in poor combustion. Therefore, the portion of the injection quantity change for a split injection is reflected in other split injections executed during the same combustion cycle. By controlling the injection quantity of each split injection in this way, an increase in injection quantity variation can be avoided without changing the total injection quantity.

[0138] Below, we will refer to Figure 10 A method of preventing an increase in injection amount deviation without changing the total injection amount of multiple divided injections will be described.

[0139] [Limited to the minimum value within the full lift control range]

[0140] Figure 10 This is a diagram for explaining an example of limiting the fuel injection pulse width using the minimum value within the full lift control range.

[0141] Figure 10 An example is shown in which the total injection amount Qal1 required for one combustion cycle is divided into two injections (two-stage injection), with the second-stage split injection amount being the minimum value Qfmin within the full lift control range. The split injection amount for each injection stage is calculated using the split ratio for each injection stage for the total injection amount Qal1. In the limiting process of this embodiment, either the maximum value Qpmax (injection pulse width TIpmax) within the partial lift control range or the minimum value Qfmin (TIfmin) within the full lift control range is selected, and the corresponding split injection amount is changed.

[0142] exist Figure 10 In the example, for the injection pulse 1001 of the first segment and the injection pulse 1002 of the second segment before the restriction processing, after the restriction processing, the injection pulse width of the injection pulse 1011 of the first segment becomes shorter, and the injection pulse width of the injection pulse 1012 of the second segment becomes longer.

[0143] For example, when the ratio of the split injection amount in the first stage is spt1 and the ratio of the split injection amount in the second stage is spt2, the split injection amount in the first stage is "Qspt1 = Qall × spt1", and the split injection amount in the second stage is "Qspt2 = Qall × spt2". Here, spt1 + spt2 = 1. Figure 10 In the example shown, the second-stage split injection amount Qspt2 is within the jump region 913, resulting in a large injection amount deviation. Therefore, the second-stage split injection amount Qspt2 is set to the minimum value Qfmin within the full lift control range, the second-stage injection pulse width is changed from "TIspt2" to "TIfmin," and the fuel injection valve 105 is energized.

[0144] Meanwhile, the second-stage split injection amount Qspt2 changes to the minimum value Qfmin within the full lift control range, increasing the total injection amount Qall by (Qfmin - Qspt2). Therefore, to prevent the total injection amount Qall from changing, the increase in the second-stage split injection amount (Qfmin - Qspt2) is subtracted from the first-stage split injection amount Qspt1, resulting in the first-stage split injection amount being set to Qspt1'. The first-stage injection pulse width is then changed from "TIspt1" to "TIspt1'," and fuel injection valve 105 is energized.

[0145] As described above, without changing the total injection amount Qall, it is possible to avoid an increase in the injection amount deviation in the second stage of divided injection in which the divided injection amount Qspt2 is located within the jumping region 913 .

[0146] [Limited to the maximum value within the partial lift control range]

[0147] Figure 11 This is a diagram for explaining an example of limiting the fuel injection pulse width to the maximum value within the full lift control range.

[0148] Figure 11 This example shows a case where the total injection quantity Qall required for one combustion cycle is divided into three times (three injection stages), with the third stage's divided injection quantity being the maximum value Qpmax within the partial lift control range. The divided injection quantity for each injection stage is calculated using the division ratio for the total injection quantity Qall. The calculation results show that after the restriction process, the injection pulse widths of the first and second stage injection pulses 1111 and 1112 become longer, while the injection pulse width of the third stage injection pulse 1113 becomes shorter, compared to the first to third stage injection pulses 1101 to 1103 before the restriction process.

[0149] For example, if the ratio of the split injection amounts in the first stage is spt1, the ratio of the split injection amounts in the second stage is spt2, and the ratio of the split injection amounts in the third stage is spt3, the split injection amounts in the first stage are "Qspt1 = Qall × spt1", the split injection amounts in the second stage are "Qspt2 = Qall × spt2", and the split injection amounts in the third stage are "Qspt3 = Qall × spt3". Here, spt1 + spt2 + spt3 = 1.

[0150] exist Figure 11 In the example shown, the third-stage split injection amount Qspt3 is within the jump region 913, resulting in a large injection amount deviation. Therefore, the third-stage split injection amount Qspt3 is set to the maximum value Qpmax within the partial lift control range, the third-stage injection pulse width is changed from "TIspt3" to "Tpmax," and energization is applied to the fuel injection valve 105.

[0151] Meanwhile, the third-stage split injection amount Qspt3 changes to its maximum value Qpmax within the partial lift control range, reducing the total injection amount Qall by (Qspt3 - Qpmax). Therefore, to prevent the total injection amount Qall from changing, the first-stage split injection amount Qspt1 is increased by half the amount (Qspt3 - Qpmax) / 2 of the increase in the third-stage split injection amount, resulting in the first-stage split injection amount being set to Qspt1'. The second-stage injection pulse width is then changed from "TIspt1" to "TIspt1'," and fuel injection valve 105 is energized.

[0152] Furthermore, the second-stage split injection amount Qspt2 is increased by half the increase in the third-stage split injection amount (Qspt3 - Qpmax) / 2, resulting in the second-stage split injection amount being Qspt2'. The second-stage injection pulse width is then changed from "TIspt2" to "TIspt2'," and fuel injection valve 105 is energized.

[0153] As described above, without changing the total injection amount Qall, it is possible to avoid an increase in the injection amount deviation of the divided injection amount Qspt3 in the third stage of divided injection within the jumping region 913 .

[0154] above Figure 10 、 Figure 11 The examples of 2-stage injection and 3-stage injection are shown in FIG. , and the same applies even if the number of divisions of the total injection amount Qall exceeds 3. Figure 10 In the example, the change of the split injection amount Qspt2 in the second stage is only reflected in the first stage, but Figure 11 As shown in FIG, the variable portion can also be distributed to multiple injection segments. Figure 11 In the example of , the fluctuation portion of the divided injection amount Qspt3 in the third stage may be reflected only in the first stage or the second stage.

[0155] As described above, when the divided injection amount is within the jump area 913, the total injection amount Qall is limited to the maximum value Qpmax (TIpmax) in the partial lift control range or the minimum value Qfmin (TIfmin) in the full lift control range without changing the total injection amount Qall.

[0156] [How to select the maximum value within the partial lift control range and the minimum value within the full lift control range]

[0157] Next, a method of selecting whether to use the maximum value Qpmax (TIpmax) in the partial lift control range or the minimum value Qfmin (TIfmin) in the full lift control range for the restriction process when the divided injection amount is within the jump region 913 will be described.

[0158] Typically, the number of split injections, the split ratio, and the timing of each energization start are determined based on combustion modes such as stratified combustion and homogeneous combustion, as well as operating scenarios such as early catalyst temperature rise control and superknock. Therefore, it is desirable to minimize changes in these parameters. Therefore, limiting processing is performed to minimize fluctuations in the injection amount and injection pulse width for each injection segment.

[0159] When the split injection amount Qsptx (x is the injection segment number) of any injection segment falls within the jump region 913, a limiting process is performed to minimize injection amount fluctuation. Specifically, the smaller of the difference (Qsptx - Qpmax) between the split injection amount Qsptx and the maximum value Qpmax within the partial lift control range, or the difference (Qfmin - Qsptx) between the split injection amount Qsptx and the minimum value Qfmin within the full lift control range is selected as the changed split injection amount Qsptx'. If (Qsptx - Qpmax) < (Qfmin - Qsptx), the maximum value Qpmax within the partial lift control range is selected as the split injection amount Qsptx. If the inequality does not hold, the minimum value Qfmin within the full lift control range is selected as the split injection amount Qsptx. Naturally, fluctuations in the split injection amount Qsptx are reflected in the split injection amounts of other injection segments.

[0160] In the above example, the limit value is selected to reduce the variation of the divided injection amount Qsptx. However, the limit processing may be performed to reduce the variation of the injection pulse width "TIsptx" (energization time) corresponding to each divided injection amount rather than reducing the variation of the divided injection amount.

[0161] In each example of the second embodiment described below, the process of reflecting the variation of the divided injection amount Qsptx of a certain injection segment on the divided injection amounts of other injection segments is the same, and therefore the description thereof will be omitted.

[0162] In addition, in the above example, the last injection section ( Figure 10 Paragraph 2, Figure 11 The case where the divided injection amount of the first or second and subsequent injection segments is limited is described, but of course the divided injection amount of the first or second and subsequent injection segments may be limited.

[0163] As described above, the fuel injection control device of embodiment 1 of the present invention (the fuel injection control device 127 of the ECU 109) includes a control unit (CPU 141), which is applied to an internal combustion engine (for example, a four-cylinder four-cycle engine) assembled with multiple fuel injection valves (105) having energizing coils, and divides the amount of fuel equivalent to the total injection amount required for one combustion into multiple injections in each combustion injection valve.

[0164] The control unit (CPU 141) is configured as follows: when the injection quantity instruction value (split injection quantity Qsptx) of any split injection among the multiple split injections is in an area outside the predetermined injection quantity deviation allowable range (within the jump area 913), the control unit (CPU 141) changes the injection quantity instruction value in an increasing direction (for example, the maximum value Qpmax within the partial lift control range) or a decreasing direction (for example, the minimum value Qfmin within the full lift control range) based on a predetermined change reference, so that the injection quantity instruction value of the corresponding split injection is within the injection quantity deviation allowable range, and changes the injection quantity instruction values ​​of other split injections so that the total injection quantity (Qall) of the multiple split injections does not change.

[0165] In the fuel injection control device (fuel injection control device 127) configured as described above, the control unit (CPU 141) performs a modification process (limitation process) on the injection quantity command value (split injection quantity Qsptx) for a split injection that is outside the allowable injection quantity deviation range (within the jitter region 913) so that the command value falls within the allowable injection quantity deviation range. This prevents the use of injection quantity command values ​​outside the allowable injection quantity deviation range, thereby preventing an increase in injection quantity deviation in the split injection quantities. Consequently, it is possible to prevent deterioration in combustion and exhaust emissions caused by fluctuations in the split injection quantities (or energization time).

[0166] In parallel with the aforementioned limiting process, the control unit (CPU 141) also reflects the changes in the corresponding split injection amount in the injection amount command values ​​of other split injections in the same combustion cycle, so that the total injection amount of the multiple split injections does not change. This prevents an increase in the injection amount deviation of the total injection amount while maintaining the total injection amount.

[0167] In addition, in the fuel injection control device (fuel injection control device 127) of the present embodiment, when the injection quantity instruction value (divided injection quantity Qsptx) is located in an area outside the injection quantity deviation allowable range (within the jump area 913), the control unit (CPU 141) changes the injection quantity instruction value (Qsptx) to the value of the minuend in the subtraction operation of the difference between the injection quantity maximum value (Qpmax) of the partial lift control range (912) and the injection quantity instruction value (Qsptx), or the difference between the injection quantity minimum value (Qfmin) of the full lift control range (914) and the injection quantity instruction value (Qsptx), whichever has the smaller absolute value.

[0168] According to the fuel injection control device having the above-mentioned structure, the injection quantity instruction value (Qsptx) of the split injection can be set without changing the total injection quantity of multiple split injections, avoiding the range (within the jump area 913) where the injection quantity deviation is easily caused by the component differences of each fuel injection valve.

[0169] Therefore, it is possible to prevent the increase in the variation in the injection amount of each fuel injection valve.

[0170] In addition, in the fuel injection control device (fuel injection control device 127) of this embodiment, the control unit (CPU 141) is configured to calculate the energization time (injection pulse width TIsptx or TIsptx') of the fuel injection valve (105) based on the injection amount command value (split injection amount Qsptx or Qsptx') of the split injection. As a result, the control unit (CPU 141) can generate a fuel injection pulse signal of the energization time (pulse width) calculated based on the injection amount command value and energize the fuel injection valve. As a result, by controlling the opening of the fuel injection valve using the energization time, fuel injection with a small injection amount deviation can be performed.

[0171] In the fuel injection control device (fuel injection control device 127) of the present embodiment, the control unit (CPU 141) includes: a valve body operation time detection unit (211) that detects the valve body operation time from the end of energization of the fuel injection valve 105 to the completion of the valve closing operation of the valve body of the fuel injection valve; and a correction amount calculation unit (fuel injection pulse signal correction amount calculation unit 212) that calculates a correction amount for the energization time of each fuel injection valve based on the valve body operation time. Then, the control unit (CPU 141) uses the correction amount to correct the energization time of the fuel injection valve calculated based on the injection amount command value of the split injection.

[0172] According to the fuel injection control device having the above structure, the control unit can detect the characteristics (valve body operation time) of the fuel injection valve (105) while the internal combustion engine is running, and calculate a correction amount for the energization time of the fuel injection valve. Thus, the control unit (CPU 141) can apply the correction amount calculated while the internal combustion engine is running to the energization time based on the injection amount command value subjected to the above-mentioned limiting process, and can adjust the energization time for each fuel injection valve. Therefore, it is possible to reduce the injection amount deviation caused by the component differences of each fuel injection valve.

[0173] <Implementation Method 2>

[0174] Next, as a second embodiment of the present invention, an example of limiting the divided injection amounts of divided injections outside the injection amount deviation allowable range based on a change criterion such as an injection parameter or an engine state (a method of selecting the divided injection amounts) will be described.

[0175] [Restriction processing based on ignition timing]

[0176] First, the limitation process based on the ignition timing will be described.

[0177] Typically, in stratified combustion, fuel injection is sometimes performed at a timing (crank angle) very close to ignition timing in the second half of the compression stroke. In this case, the injection pulse width becomes longer due to the implementation of the restriction process, which may cause fuel to adhere to the spark plug 106 or unburned fuel to be discharged. Therefore, when the injection amount of the split injection, in which the fuel injection is performed within a specified angle until ignition timing, is within the jump region 913, the restriction process is implemented to shorten the injection pulse width.

[0178] use Figure 12 The restriction process based on the above-mentioned ignition timing will be described in detail.

[0179] Figure 12 This is a time chart showing an example of a process for limiting the fuel injection pulse width of the injection close to the ignition timing.

[0180] Figure 12 This example shows two-stage injection in N cylinders, with an injection pulse width 1201 corresponding to the first-stage split injection amount Qspt1 and an injection pulse width 1202 corresponding to the second-stage split injection amount Qspt2. Injection pulse width 1202 outputs injection pulses from energization start timing T1211 to energization stop timing T1212. Injection inhibit timing T1222 is a timing pre-set based on ignition timing T1223 and is set with a time margin to eliminate the possibility of fuel adhering to spark plug 106 or unburned fuel being discharged.

[0181] Normally, if the injection pulse continues to be energized beyond the injection inhibit timing T1222, the injection pulse is forcibly shut off and the energization is stopped. In this case, due to the forced cessation of energization, the actual injection amount falls short of the required injection amount. Of course, the energization start timing T1211 is typically set so that energization does not exceed the injection inhibit timing T1222.

[0182] Injection inhibit warning timing T1221 is calculated in advance through experiments so that it is a predetermined interval from injection inhibit timing T1222. It is used to determine when the current crank angle is close to injection inhibit timing T1222. In other words, if energization stop timing T1212 is after injection inhibit warning timing T1221, there is a possibility that energization stop timing T1212 is after injection inhibit timing T1222. Therefore, the injection pulse width is limited to the maximum value Qpmax within the partial lift control range, rather than the minimum value Qfmin within the full lift control range where the injection pulse width is lengthened, so that the changed injection pulse width is shorter than the current injection pulse width.

[0183] As a result, the injection pulse width 1202 is changed in a shortening direction, and the time from the energization stop timing T1212 to the ignition timing T1223 can be extended.

[0184] In addition, the comparison and determination with the injection prohibition warning timing T1221 may use the energization start timing T1211 instead of the energization stop timing T1212. In this case, the injection pulse width 1202 is assumed to be long, and the injection prohibition warning timing T1221 is set in the direction of the advance angle.

[0185] The crank angle can be arbitrarily determined. For example, the crank angle can be expressed as a crank angle after top dead center (°ATDC) based on intake top dead center or a crank angle before top dead center (°BTDC) based on compression top dead center.

[0186] [Stroke Limitation Processing Based on Split Injection]

[0187] In addition, although reference has been made to Figure 12 While the example described above determines the restriction based on ignition timing, it is also possible to determine the restriction based on the stroke in which split injection is performed. Normally, the piston descends during the intake stroke, allowing for a relatively long energizing time. However, since the piston ascends during the compression stroke, extending the energizing time can cause fuel to adhere to the piston crown.

[0188] Therefore, during the intake process, the split injection amount is limited to the minimum value Qfmin within the full lift control range, where the injection pulse width increases. Specifically, when at least one of the split injection energization start timing (T1211) or energization stop timing (T1212) occurs during the intake stroke, the injection amount command value is changed to the minimum injection amount value (minimum value Qfmin) within the full lift control range.

[0189] Meanwhile, during the compression stroke, the split injection amount is limited to its maximum value, Qpmax, within the partial lift control range, where the injection pulse width shortens. Specifically, when at least one of the split injection energization start timing (T1211) or energization stop timing (T1212) occurs during the compression stroke, the injection amount command value is changed to the maximum injection amount within the partial lift control range (maximum value Qpmax).

[0190] [Restriction processing based on the number of injection stages]

[0191] Alternatively, the restriction process can be determined based on the number of injection stages rather than the stroke duration of the split injection. In this case, since the crank angle and other parameters do not need to be determined, split injection control can be simplified. This restriction process will be described using the example of a three-stage injection process.

[0192] When the split injection amount of the first or second stage is within the jump region 913, the injection pulse width may be limited to the minimum value Qfmin within the full lift control range, where the injection pulse width is lengthened. Specifically, when the injection amount command value (split injection amount Qsptx) is outside the injection amount deviation allowable range (within the jump region 913), and the order of the corresponding split injection is before the specified order among the multiple split injections, the control unit (CPU 141) changes the injection amount command value to the minimum injection amount value (minimum value Qfmin) within the full lift control range.

[0193] Furthermore, when the third-stage split injection amount is within the jump region 913, the time until ignition timing is taken into account, and the maximum value Qpmax within the partial lift control range, where the injection pulse width is shortened, is used for limitation. Specifically, when the injection amount command value (split injection amount Qsptx) is outside the injection amount deviation allowable range (within the jump region 913), and the order of the corresponding split injections is after the predetermined order among the multiple split injections, the control unit (CPU 141) changes the injection amount command value to the maximum injection amount (maximum value Qpmax) within the partial lift control range.

[0194] The split injection amount of the first stage (first split injection) can be simply limited to the minimum value Qfmin within the full lift control range, and the split injection amount of the third stage (last split injection) can be limited to the maximum value Qpmax within the partial lift control range.

[0195] [Restriction processing based on injection interval]

[0196] Next, use Figure 13 The restriction process based on the injection interval will be described.

[0197] Figure 13 1 is a timing chart showing an example of a process of limiting the fuel injection pulse width of an injection with a short injection interval. Figure 13 This is an example of performing two-stage injection in N cylinders, and shows an injection 1301 corresponding to the first-stage divided injection amount Qspt1 and an injection 1302 corresponding to the second-stage divided injection amount Qspt2 before the restriction process.

[0198] If the injection interval shortens, energization for the next injection begins before valve body 402 closes, leaving valve body 402 open. Consequently, prolonged penetration increases fuel wall flow, potentially leading to unburned gas emissions. For example, if the split injection amount for injection 1302 is within the pulsating region 913 and is limited by the maximum value Qpmax within the partial lift control range, the injection pulse width in the preceding injection 1301 is lengthened to increase the split injection amount. Specifically, the injection interval 1320 between the energization stop timing T1313 for the preceding injection 1301 and the energization start timing T1311 for the following injection 1302 shortens.

[0199] Since the previous de-energization timing T1313 is delayed, the injection interval 1320 is shortened, and the time required to close the valve body 402 may not be ensured. Therefore, when the injection interval 1320 between the de-energization timing T1311 and the previous de-energization timing T1313 is equal to or less than the specified value and the split injection amount is within the jump area 913, the split injection amount Qsptx is limited to the minimum value Qfmin (TIfmin) within the full lift control range.

[0200] like Figure 13As shown, if the next injection 1332 is limited to the minimum value Qfmin within the full lift control range, the injection pulse width of the previous injection 1331 is shortened to reduce the split injection amount. In other words, the injection interval 1350 between the energization stop timing T1243 of the previous injection 1331 and the energization start timing T1311 of the next injection 1332 is lengthened. The specified value for this injection interval is determined in advance through experiments and is set to be longer than the minimum value of the injection interval required to ensure valve closing time.

[0201] When the injection pulse width of the previous injection 1301 is long and the injection interval 1320 is below the specified value, and the divided injection amount is within the jumping area 913, the maximum value Qpmax within the partial lift control range is used for limitation processing to shorten the injection pulse width of the injection 1301.

[0202] Thus, the injection interval 1320 is lengthened, ensuring valve closing time. Then, the divided injection amount of the next injection 1302 is increased by the amount of the divided injection amount reduced by the shortening of the injection pulse width of the injection 1301, thereby keeping the total injection amount constant.

[0203] [Limitation Processing Based on Drive Voltage or Drive Current]

[0204] Next, the limitation process based on the driving voltage or the driving current will be described.

[0205] Figure 14 This is a timing chart explaining an example of a process for limiting the fuel injection pulse width of an injection with a small drive voltage or drive current.

[0206] If the driving voltage (high voltage 210) applied to the fuel injection valve 105 becomes lower, the valve opening force for opening the valve body 402 becomes weaker, the valve opening speed becomes slower, and a valve opening failure may occur. Therefore, when the high voltage 210 is low, the power-on time is extended for injections with a short power-on time, and the proportion of the injection amount reduction due to the valve opening delay becomes smaller. For example, Figure 14 As shown, when high voltage 210 is below threshold value 1401, split injection amount Qsptx is limited to the minimum value Qfmin (TIfmin) within the full lift control range. This increases the injection pulse width. Therefore, if the injection pulse width corresponding to split injection amount Qsptx is set to TIsptx, the energization time can be extended by (TIfmin - TIsptx).

[0207] In addition, Figure 14In the embodiment of the present invention, the injection pulse is in the on state, but before the injection pulse is turned on, it is necessary to determine the limiting process, that is, the split injection amount (power-on time). Therefore, before turning on the injection pulse, it is sufficient to measure the high voltage 210. In addition, the driving voltage may not be the voltage obtained by boosting the battery voltage 209 by the high voltage generating unit 206, but the battery voltage 209 as the original power supply voltage may be used. That is, when the battery voltage 209 is below the threshold, the split injection amount Qsptx is limited to the minimum value Qfmin (TIfmin) within the full lift control range. Of course, the threshold in this case needs to be set to be less than the threshold 1401 according to the battery voltage 209.

[0208] In addition, the above description describes an example of limiting processing based on the high voltage 210, but limiting processing can also be performed based on the drive current. As described above, the high voltage 210 is applied after the injection pulse is turned on, and the high voltage 210 is continued to be applied until the drive current reaches the peak current value calculated by the fuel injection drive waveform instruction unit 203. However, when the set value (instruction value) of the peak current is small, it may not be possible to apply sufficient force to the valve body 402 to open the valve, resulting in slower valve opening or failure to open the valve. Therefore, when the set value (instruction value) of the peak current is less than the threshold value 1402, the split injection amount Qsptx is limited to the minimum value Qfmin (TIfmin) within the full lift control range, thereby lengthening the injection pulse width.

[0209] As described above, by performing the restriction process in the direction of increasing the divided injection amount, the ratio of the injection amount reduction caused by the reduction in the valve opening speed can be reduced, and an increase in the injection amount variation can be suppressed.

[0210] The fuel injection control device (fuel injection control device 127) of the second embodiment described above can achieve the same effects as the first embodiment. Specifically, in this embodiment, based on a change criteria such as injection parameters or engine conditions, the split injection amount is limited using either the maximum value (Qpmax) within the partial lift control range or the minimum value (Qfmin) within the full lift control region. This prevents the use of injection amount command values ​​(Qsptx) outside the permissible injection amount deviation range (within the jump region 913), thereby preventing increases in injection amount deviation within the split injection amount. Consequently, it is possible to prevent deterioration in combustion and exhaust emissions caused by fluctuations in the split injection amount (or energization time).

[0211] Furthermore, in this embodiment, in parallel with the aforementioned limiting process, the change in the corresponding split injection amount is reflected in the injection amount command values ​​of other split injections in the same combustion cycle, so that the total injection amount of the multiple split injections does not change. This maintains the total injection amount while preventing an increase in injection amount variation within the total injection amount.

[0212] The present invention is not limited to the above-described embodiments, and various other application examples and modified examples are of course possible without departing from the gist of the present invention described in the claims.

[0213] For example, the above-mentioned embodiments provide a detailed and specific description of the structure of the fuel injection control device in order to facilitate the understanding of the present invention. However, the present invention is not necessarily limited to having all the structural elements described. In addition, a portion of the structure of a certain embodiment may be replaced with a component of another embodiment. In addition, the component of another embodiment may be added to the structure of a certain embodiment. In addition, other components may be added, replaced, or deleted from a portion of the structure of each embodiment.

[0214] Furthermore, some or all of the aforementioned components, functions, and processing units may be implemented in hardware, for example, by designing them as integrated circuits. Broadly speaking, processor devices such as FPGAs (Field Programmable Gate Arrays) and ASICs (Application Specific Integrated Circuits) may also be used as hardware.

[0215] Description of labels

[0216] 101…internal combustion engine, 105…fuel injection valve, 109…ECU, 127…fuel injection control device, 201…split injection instruction unit, 202…fuel injection pulse signal calculation unit, 203…fuel injection drive waveform instruction unit, 211…valve body action time detection unit, 212…fuel injection pulse signal correction amount calculation unit, 221…split injection amount calculation unit, 222…fuel injection pulse signal instruction unit, 223…fuel injection pulse signal limiting unit, 214…engine status detection unit, 407…solenoid.

Claims

1. A fuel injection control device for an internal combustion engine equipped with a plurality of fuel injection valves each having an energizing coil, wherein each fuel injection valve injects fuel in a divided manner into a plurality of injections corresponding to a total injection amount required for one combustion, the fuel injection control device being characterized in that: The control unit includes a control unit that, when an injection amount instruction value of any split injection among a plurality of split injections is outside a predetermined injection amount deviation allowable range, changes the injection amount instruction value of the corresponding split injection in an increasing direction or a decreasing direction based on a predetermined change reference so that the injection amount instruction value is within the injection amount deviation allowable range, and changes the injection amount instruction values ​​of other split injections so that the total injection amount of the plurality of split injections does not change. The region where the injection quantity instruction value of the split injection is outside the injection quantity deviation allowable range refers to: The injection quantity command value for the split injection is a value that exceeds a maximum injection quantity within a partial lift control range in which energization is stopped before the valve body of the fuel injection valve reaches a fully open position, and is a value that is smaller than a minimum injection quantity within a full lift control range in which energization is stopped after the valve body of the fuel injection valve reaches a fully open position. The change reference includes the difference between the maximum injection quantity or the minimum injection quantity within the partial lift control range and the injection quantity instruction value, the crank angle of the power start timing or the power stop timing, the interval between the power stop timing of the previous segment of the split injection and the power start timing of the next segment of the split injection in the continuous split injection, the voltage applied to the coil of the fuel injection valve or the energized current, the stroke in which the power start timing or the power stop timing of the split injection is located, or the order of the split injection in the multiple split injections.

2. The fuel injection control device according to claim 1, wherein When the injection quantity instruction value is in an area outside the injection quantity deviation allowable range, the control unit changes the injection quantity instruction value to the value of the minuend in the subtraction operation of the smaller absolute value of the difference between the injection quantity maximum value within the partial lift control range and the injection quantity instruction value, and the difference between the injection quantity minimum value within the full lift control range and the injection quantity instruction value.

3. The fuel injection control device according to claim 1, wherein: In a case where the injection quantity instruction value is located in an area outside the allowable range of the injection quantity deviation, when at least either one of the power-on start timing and the power-on stop timing is greater than a prescribed crank angle predetermined based on the ignition timing, the control unit changes the injection quantity instruction value to the maximum injection quantity within the partial lift control range.

4. The fuel injection control device according to claim 1, wherein: In continuous split injections, when the injection quantity instruction value of the subsequent split injection is located in an area outside the injection quantity deviation allowable range, when the interval between the power-on stop timing of the previous split injection and the power-on start timing of the subsequent split injection is less than a predetermined specified value, the control unit changes the injection quantity instruction value to the minimum injection quantity within the full lift control range.

5. The fuel injection control device according to claim 1, wherein: When the injection quantity instruction value is located in an area outside the allowable range of the injection quantity deviation, when the voltage applied to the coil of the fuel injection valve or the current energized is less than a specified value, the control unit changes the injection quantity instruction value to the minimum injection quantity value within the full lift control range.

6. The fuel injection control device according to claim 1, wherein: When the injection quantity instruction value is located in an area outside the injection quantity deviation allowable range, when at least one of the power-on start timing and the power-on stop timing of the split injection is in the intake stroke, the control unit changes the injection quantity instruction value to the minimum injection quantity value within the full lift control range.

7. The fuel injection control device according to claim 1, wherein: In a case where the injection quantity instruction value is located in an area outside the injection quantity deviation allowable range, when at least either one of the energization start timing and the energization stop timing of the split injection is in a compression stroke, the control unit changes the injection quantity instruction value to a maximum injection quantity value within the partial lift control range.

8. The fuel injection control device according to claim 1, wherein: When the injection amount command value is outside the injection amount deviation allowable range, the control unit changes the injection amount command value to a maximum injection amount within the partial lift control range when the order of the divided injections is a predetermined order or later in the plurality of divided injections.

9. The fuel injection control device according to claim 1, wherein: When the injection amount command value is outside the injection amount deviation allowable range, and when the order of the divided injections is before a predetermined order in the plurality of divided injections, the control unit changes the injection amount command value to a minimum injection amount value within the full lift control range.

10. The fuel injection control device according to any one of claims 1 to 9, characterized in that: The control unit calculates an energization time for the fuel injection valve based on the injection amount command value of the divided injection.

11. The fuel injection control device according to claim 10, wherein: The control unit includes: a valve body operation time detection unit for detecting a valve body operation time from when power supply to the fuel injection valve is terminated to when a valve body of the fuel injection valve completes a valve closing operation; and a correction amount calculation unit that calculates a correction amount of the energization time for each of the fuel injection valves based on the valve body operation time; The correction amount is used to correct the energization time of the fuel injection valve calculated based on the injection amount command value of the divided injection.

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