Fuel injection control device

Abstract

The present invention prevents erroneous judgment by judging whether the abnormal judgment of fuel injection is performed normally. The fuel injection control device (127) controls a plurality of fuel injection valves having an energizing coil, and includes: a driving state detection unit (211) for detecting the driving state of the fuel injection valve according to the energizing current or applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit (213) for detecting the injection abnormality of the fuel injection valve by comparing the fuel injection instruction with the driving state of the fuel injection valve; and an injection abnormality detection execution judgment unit (212) for judging whether the injection abnormality detection performed by the injection abnormality detection unit (213) can be performed based on the state of the internal combustion engine.

Description

Technical Field

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

[0002] Regarding particulate matter, which is one of the exhaust gas components causing air pollution, it is known that fuel injected from a fuel injection valve adheres to a piston top surface or a cylinder bore in a combustion chamber without burning, thereby forming particulate matter.

[0003] Therefore, if the attached fuel can be reduced, particulate matter (PN, PM) can be suppressed. For example, in order to shorten the spray length (penetration) of the fuel injected from the fuel injection valve so that the injected fuel does not hit the piston top surface or the cylinder hole, split injection that performs multiple injections in one combustion cycle can be used.

[0004] The fuel injection amount calculation when performing split injection is performed, and the fuel injection amount when a fuel injection is performed once in one combustion cycle is taken as the total injection amount. The fuel injection amount per split injection number obtained by dividing the split injection number by the split ratio is used to control the driving of the fuel injection valve.

[0005] In such split injection, it is desirable to have the following functions: for the calculated injection request (fuel injection amount, injection start timing, split injection number, etc.), the fuel injection valve is normally energized, whether the fuel injection is executed according to the injection request is monitored, and whether there is any abnormality.

[0006] In Patent Document 1, in split injection in which fuel is injected multiple times from a fuel injection valve in one combustion cycle, the change points of the drive current flowing into the fuel injection valve and the applied drive voltage are counted to determine whether fuel injection is executed according to the split injection number as the injection request.

[0007] In Patent Document 2, abnormality detection of split injection is performed by detecting a drive current flowing into a fuel injection valve and comparing it with the energization start timing and energization time calculated by detecting energization and non-energization.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent document 1: International Publication No. 2016 / 129402;

[0011] Patent Document 2: Japanese Patent Application Publication No. 2013-36344. Summary of the invention

[0012] Technical problem to be solved by the invention

[0013] However, the technologies described in the above-mentioned patent documents 1 and 2 do not take into account the state of the internal combustion engine, such as the driving state of the fuel injection valve, which may be misjudged as abnormal even though the split injection is normally executed. Therefore, in some internal combustion engine states, even though the split injection is normally executed, it is possible that the fail-safe control is accidentally executed, such as stopping the fuel injection, due to being judged as abnormal.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel injection control device that prevents erroneous determination in abnormality determination of determining whether a fuel injection valve is normally performing fuel injection.

[0015] Technical solutions to solve problems

[0016] In order to solve the above-mentioned technical problems, a fuel injection control device of one embodiment of the present invention controls multiple fuel injection valves having energized coils, including: a fuel injection pulse output unit, which outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection instruction; a driving state detection unit, which detects the driving state of the fuel injection valve according to the energized current or applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit, which detects the injection abnormality of the fuel injection valve by comparing the fuel injection instruction with the driving state of the fuel injection valve; and an injection abnormality detection execution judgment unit, which judges whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is judged that it is not executable.

[0017] Effects of the Invention

[0018] According to at least one aspect of the present invention, it is possible to prevent erroneous determination (false determination) in abnormality determination of determining whether or not a fuel injection valve has normally performed fuel injection.

[0019] Technical problems, structures, and effects other than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an overall configuration diagram showing a basic configuration example of an internal combustion engine system equipped with a fuel injection control device according to an embodiment of the present invention.

[0021] Figure 2 This is a block diagram showing an example of the internal structure of a fuel injection control device according to an embodiment of the present invention.

[0022] Figure 3 This is a circuit diagram showing a configuration example of a fuel injection drive unit in a fuel injection control device according to an embodiment of the present invention.

[0023] Figure 4This is a timing chart for explaining a method for driving a fuel injection valve according to an embodiment of the present invention.

[0024] Figure 5 This is a diagram for explaining the single injection control and the split injection control according to one embodiment of the present invention.

[0025] Figure 6 This is a timing chart for explaining a drive current detection signal of a fuel injection valve according to an embodiment of the present invention.

[0026] Figure 7 This is a timing chart for explaining the operation of the divided injection abnormality detection unit according to one embodiment of the present invention.

[0027] Figure 8 This is a diagram for explaining an abnormal state that can be detected by the divided injection abnormality detection unit according to one embodiment of the present invention.

[0028] Fig. 9 This is a timing chart for explaining a case where the split injection abnormality determination is not performed at the injection interval according to an embodiment of the present invention.

[0029] Fig.10 This is a timing chart for explaining a case where the injection pulse width according to an embodiment of the present invention does not perform the divided injection abnormality judgment.

[0030] Fig.11 This is a timing chart for explaining a case where the boost voltage according to one embodiment of the present invention does not perform the split injection abnormality determination.

[0031] Fig.12 This is a timing chart (part 1) for explaining a case where the divided injection abnormality determination is not performed at the forced end timing according to one embodiment of the present invention.

[0032] Fig.13 This is a timing chart (part 2) for explaining a case where the divided injection abnormality determination is not performed at the forced end timing according to one embodiment of the present invention. DETAILED DESCRIPTION

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

[0034] <One embodiment> [Internal combustion engine system]

[0035] First, the configuration of an internal combustion engine system in which a fuel injection control device according to an embodiment of the present invention is mounted will be described. Figure 1 It is an overall configuration diagram of an internal combustion engine system equipped with a fuel injection control device according to an embodiment.

[0036] Figure 1 The internal combustion engine (engine) 101 shown is a four-stroke engine that repeats the four strokes of intake stroke, compression stroke, combustion (expansion) stroke, and exhaust stroke, for example, a multi-cylinder engine having four cylinders. In addition, the number of cylinders of the internal combustion engine 101 is not limited to four, and may be any number of cylinders such as six or eight or more.

[0037] The internal combustion engine 101 has a piston 102, an intake valve 103, and an exhaust valve 104. The gas (intake air) entering the internal combustion engine 101 passes through an air flow meter (AFM) 120 that detects the amount of inflowing air, and the flow rate is adjusted by a throttle valve 119. The air that has passed through the throttle valve 119 is sucked into a collector 115 as a branching part, and then supplied to a combustion chamber 121 of each cylinder through an intake pipe 110 and an intake valve 103 provided for each cylinder.

[0038] On the other hand, the fuel is supplied from the fuel tank 123 to the high-pressure fuel pump 125 by the low-pressure fuel pump 124, and the fuel is increased to a pressure required for fuel injection by the high-pressure fuel pump 125. That is, the high-pressure fuel pump 125 moves a plunger provided in the high-pressure fuel pump 125 up and down under the action of power transmitted from an exhaust cam shaft (not shown) of an exhaust cam 128, thereby pressurizing (increasing) the fuel in the high-pressure fuel pump 125.

[0039] An on-off valve driven by a solenoid is provided at the suction port of the high-pressure fuel pump 125. The solenoid is connected to a fuel injection control device 127 provided in an ECU (Engine Control Unit) 109 as an electronic control device. The fuel injection control device 127 controls the solenoid based on a control instruction from the ECU 109 and drives the on-off valve so that the pressure of the fuel discharged from the high-pressure fuel pump 125 (hereinafter referred to as "fuel pressure") becomes the desired pressure. As an example, the ECU 109 (fuel injection control device 127) includes a CPU 141, a memory 142, and an input / output interface not shown in the figure.

[0040] CPU141 is a processor that performs calculation processing. Memory 142 is a storage unit composed of volatile or non-volatile semiconductor memory and the like. A computer program for controlling the fuel injection valve 105 can also be stored in the memory 142. In this case, all or part of the functions of the fuel injection control device 127 are realized by reading out and executing the computer program recorded in the memory 142 by CPU141. An ignition switch signal for instructing (instructing) the start (ignition) of the internal combustion engine 101 is input to ECU109. For example, when CPU141 detects that the ignition switch signal is turned on, it starts the computer program processing of the fuel injection control. In addition, other calculation processing devices such as MPU (Micro Processing Unit) can also be used instead of CPU141.

[0041] The fuel pressurized by the high-pressure fuel pump 125 is sent to the fuel injection valve 105 via the high-pressure fuel pipe 129. The fuel injection valve 105 directly injects the fuel into the combustion chamber 121 based on the command of the fuel injection control device 127. The fuel injection valve 105 is an electromagnetic valve that operates the valve body and performs fuel injection by supplying (energizing) a driving current to the electromagnetic coil described later.

[0042] In addition, the internal combustion engine 101 is provided with a fuel pressure sensor 126 for measuring the fuel pressure in the high-pressure fuel pipe 129. Based on the measurement result of the fuel pressure sensor 126, the ECU 109 sends a control command for making the fuel pressure in the high-pressure fuel pipe 129 a desired pressure to the fuel injection control device 127. That is, the ECU 109 performs so-called feedback control to make the fuel pressure in the high-pressure fuel pipe 129 a desired pressure.

[0043] 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 an electrode portion in the combustion chamber 121, and ignites a mixed gas of intake air and fuel in the combustion chamber 121 by discharge. The ignition coil 107 generates a high voltage for discharge by the spark plug 106. The water temperature sensor 108 measures the temperature of cooling water for cooling the cylinders of the internal combustion engine 101.

[0044] The ECU 109 controls the energization of the ignition coil 107 and the ignition of the spark plug 106. The mixed gas obtained by mixing intake air and fuel in the combustion chamber 121 is burned by sparks released from the spark plug 106, and the piston 102 is pressed by the pressure.

[0045] The exhaust gas generated by the combustion is discharged to the exhaust pipe 111 through the exhaust valve 104. In addition, the exhaust pipe 111 is provided with a three-way catalyst 112 and an oxygen sensor 113. The three-way catalyst 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. Based on the detection result of the oxygen sensor 113, the ECU 109 performs feedback control so that the fuel injection amount supplied from the fuel injection valve 105 becomes the target air-fuel ratio.

[0046] In addition, the piston 102 is connected to a crankshaft 131 via a connecting rod 132. The reciprocating motion (reciprocating motion) of the piston 102 is converted into a rotational motion by the crankshaft 131. In addition, a crank angle sensor 116 is installed 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.

[0047] The ECU 109 receives input 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 (accelerator pedal) operated by a driver, a fuel pressure sensor 126 , and the like.

[0048] ECU109 calculates the requested torque (required torque) of the internal combustion engine 101 based on the signal supplied from the accelerator opening sensor 122, and determines whether it is in an idle state, etc. In addition, ECU109 calculates the amount of intake air required by the internal combustion engine 101 based on the requested torque, etc., and outputs the corresponding opening signal to the throttle valve 119.

[0049] In addition, the ECU 109 has a rotation speed detection unit that calculates the rotation speed of the internal combustion engine 101 (hereinafter referred to as the engine speed) based on the signal supplied from the crank angle sensor 116. Furthermore, the ECU 109 has a warm-up determination unit that determines whether the three-way catalyst 112 is in a warm-up (preheated) state based on the temperature of the cooling water obtained from the water temperature sensor 108 and the elapsed time after the internal combustion engine 101 is started.

[0050] The fuel injection control device 127 calculates the amount of fuel according to the amount of intake air, and outputs a fuel injection signal according to the amount of fuel injection to the fuel injection valve 105. Furthermore, the fuel injection control device 127 outputs an energization signal to the ignition coil 107 and an ignition signal to the spark plug 106.

[0051] [Structure of fuel injection control device]

[0052] Next, use Figure 2 and Figure 3 right Figure 1 The structure of the fuel injection control device 127 shown in FIG. 1 will be described.

[0053] Figure 2 It is a block diagram showing an example of the internal structure of the fuel injection control device 127. Figure 3 Yes means Figure 2 A circuit diagram of a configuration example of a fuel injection drive unit is shown.

[0054] like Figure 2 As shown, the fuel injection control device 127 includes: a split injection control instruction unit 201 as a fuel injection control unit, a fuel injection pulse signal calculation unit 202, a fuel injection drive waveform instruction unit 203, an engine state detection unit 214, and a driver IC 208. In addition, the fuel injection control device 127 includes: a high voltage generation unit (boosting device) 206, fuel injection drive units 207a, 207b, a fuel injection valve drive state detection unit 211, a split injection abnormality detection execution judgment unit 212, and a split injection abnormality detection unit 213.

[0055] The engine state detection unit 214 collects and provides various information such as the above-mentioned engine speed, intake air amount, cooling water temperature, fuel pressure, and failure state of the internal combustion engine 101.

[0056] The split injection control instruction unit 201 determines whether to execute the split injection control based on the operating state or operating scene (e.g., urban driving, high-speed driving, etc.) of the internal combustion engine 101 obtained based on various information obtained from the engine state detection unit 214. When the split injection control is permitted, the split injection number, the split ratio of the fuel injection amount, the respective injection start timings, the fuel injection amount, etc. are calculated. Of course, when the split injection control is not executed, only one fuel injection is performed in one combustion cycle.

[0057] The fuel injection pulse signal calculation unit 202 (an example of a fuel injection pulse output unit) calculates the injection pulse width of the fuel injection period (power-on period) of the fuel injection valve 105 based on various information such as the number of split injections, the split ratio of the fuel injection amount, and the requested injection amount obtained from the split injection control instruction unit 201. The fuel injection pulse signal calculation unit 202 outputs the injection pulse signal of the calculated injection pulse width to the driver IC 208 according to the injection start time.

[0058] The fuel injection drive waveform command unit 203 calculates a command value of a drive current supplied for opening and maintaining the fuel injection valve 105 based on various information such as fuel pressure obtained from the engine state detection unit 214 , and outputs it to the driver IC 208 .

[0059] The battery voltage 209 is supplied to the high voltage generating unit 206 via the fuse 204 and the relay 205. The high voltage generating unit 206 generates the high power supply voltage 210 (VH) required when the electromagnetic solenoid fuel injection valve 105 opens the valve based on the battery voltage 209. Hereinafter, the power supply voltage 210 is referred to as "boosted voltage 210". As the power supply of the fuel injection valve 105, there are two systems: the boosted voltage 210 for the purpose of ensuring the valve opening force of the valve body, and the battery voltage 209 for keeping the valve open after opening the valve so that the valve body does not close the valve.

[0060] The fuel injection driving unit 207a (switching unit) is provided on the upstream side (power supply side, high voltage side) of the fuel injection valve 105, and supplies the boost voltage 210 required to open the fuel injection valve 105 to the fuel injection valve 105. In addition, after opening the fuel injection valve 105, the fuel injection driving unit 207a supplies the battery voltage 209 required to keep the fuel injection valve 105 in the open state to the fuel injection valve 105.

[0061] like Figure 3 As shown, the fuel injection driving unit 207a has diodes 301, 302, a high voltage side switching element 303, and a low voltage side switching element 304. The fuel injection driving unit 207a supplies the boosted voltage 210 supplied from the high voltage generating unit 206 to the fuel injection valve 105 using the high voltage side switching element 303 through the diode 301 provided to prevent current reverse flow.

[0062] The fuel injection driving unit 207 a supplies the battery voltage 209 supplied via the relay 205 to the fuel injection valve 105 using the low voltage side switching element 304 through a diode 302 provided to prevent a reverse current flow.

[0063] The fuel injection drive unit 207b (switching unit) is provided on the downstream side (ground side, low voltage side) of the fuel injection valve 105, and has a switching element 305 and a shunt resistor 306. The fuel injection drive unit 207b applies the power supplied from the upstream fuel injection drive unit 207a to the fuel injection valve 105 by turning on the switching element 305. In addition, the fuel injection drive unit 207b detects the current consumed in the fuel injection valve 105 using the shunt resistor 306.

[0064] Figure 2The driver IC 208 shown controls the fuel injection driver 207a, 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 instruction unit 203. That is, the driver IC 208 controls the boost voltage 210 and the battery voltage 209 applied to the fuel injection valve 105, and controls the drive current supplied to the fuel injection valve 105.

[0065] In addition, a diode 309 is forward connected between the downstream side of the solenoid 407 and the high voltage generating unit 206, and a diode 308 is forward connected between the shunt resistor 306 and the upstream side of the solenoid 407. When the high voltage side switching element 303, the low voltage side switching element 304, and the switching element 305 are turned off, the diode 308 and the diode 309 are energized by the back electromotive force generated in the solenoid 407 of the fuel injection valve 105. As a result, the current returns to the high voltage generating unit 206 side, and the drive current supplied to the solenoid 407 is rapidly reduced. At this time, a voltage (-VH) of reverse polarity is generated between the terminals of the solenoid 407 as a back electromotive force, for example, with a magnitude equivalent to the boost voltage 210.

[0066] The fuel injection valve drive state detection unit 211 (an example of a drive state detection unit) monitors the current flowing through the fuel injection valve 105 (solenoid 407) and detects whether the current has reached a predetermined current value. Furthermore, the fuel injection valve drive state detection unit 211 outputs a power-on detection signal as a detection result to the split injection abnormality detection unit 213. In addition, the fuel injection valve drive state detection unit 211 may also measure the applied voltage of the fuel injection valve 105 (solenoid 407) to detect the drive state of the fuel injection valve.

[0067] The split injection abnormality detection execution judgment unit 212 (an example of the injection abnormality detection execution judgment unit) judges whether the split injection abnormality detection unit 213 can execute the split injection abnormality detection based on the information input from the engine state detection unit 214, the fuel injection pulse signal calculation unit 202, etc. In addition, the split injection abnormality detection execution judgment unit 212 outputs the judgment result (permission signal, non-permission signal) of whether the split injection abnormality detection can be executed to the split injection abnormality detection unit 213.

[0068] The split injection abnormality detection unit 213 (an example of an injection abnormality detection unit) performs split injection abnormality detection when permission is obtained from the split injection abnormality detection execution judgment unit 212. The split injection abnormality detection unit 213 compares the power-on detection signal (power-on state) detected by the fuel injection valve drive state detection unit 211 with the injection start time (fuel injection command) calculated by the split injection control command unit 201 to perform abnormality judgment. In other words, it is judged whether a current flows through the solenoid 407 of the fuel injection valve 105 or a voltage is applied to the solenoid 407 according to the fuel injection command.

[0069] The details of the fuel injection valve driving state detection unit 211, the divided injection abnormality detection execution determination unit 212, and the divided injection abnormality detection unit 213 will be described later.

[0070] [Method of driving the fuel injection valve]

[0071] Next, refer to Figure 4 A method of driving the fuel injection valve 105 will be described.

[0072] Figure 4 This is a timing chart for explaining a method of driving the fuel injection valve 105. The horizontal axis represents time, and the vertical axis represents the injection pulse, the driving voltage, and the driving current.

[0073] Figure 4 An example of the injection pulse, driving voltage, and driving current when the fuel is injected from the fuel injection valve 105 is shown in time series. When the fuel injection valve 105 is driven, the current setting value (peak current Ip, holding current Ih, etc.) is preset based on the characteristics of the fuel injection valve 105. Then, the injection amount characteristics of the fuel injection valve 105 based on the current setting value are stored in the memory 142 (for example, RAM) provided in 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 amount characteristics of the fuel injection valve 105.

[0074] exist Figure 4 At time T400 to T401 shown in FIG. 1 , the fuel injection pulse signal calculation unit 202 (see FIG. 1 ) calculates the fuel injection pulse signal. Figure 2 ) is in the OFF state. Therefore, the fuel injection drive units 207a and 207b are in the OFF state, and the drive current does not flow through the fuel injection valve 105. Therefore, the fuel is not injected from the fuel injection valve 105.

[0075] Next, at time T401, the injection pulse is turned on, and the fuel injection drive unit 207a (switching element 303) and the fuel injection drive unit 207b (switching element 305) are turned on. As a result, the boost voltage 210 (driving voltage) is applied to the solenoid 407, and the driving current flows through the solenoid 407 (fuel injection valve 105). When the driving current is applied to the fuel injection valve 105, the valve body begins to move in the valve opening direction, and the fuel injection valve 105 opens. As a result, fuel is injected from the fuel injection valve 105.

[0076] When the drive current reaches the peak current Ip (time T402), the switch elements 303 and 304 of the fuel injection drive units 207a and 207b are turned off to reduce the drive current flowing through the fuel injection valve 105.

[0077] From the time T403 to the time T404 when the injection pulse falls, the fuel injection drive unit 207b (switching element 305) is maintained in the on state, and the fuel injection drive unit 207a (switching element 304) is intermittently in the on state. That is, by performing PMW (Pulse Width Modulation) control on the fuel injection drive unit 207a, the driving voltage applied to the fuel injection valve 105 is intermittently the battery voltage 209, and the driving current flowing through the fuel injection valve 105 is within a specified range centered on the holding current Ih.

[0078] At time T404, the injection pulse is turned off. As a result, the fuel injection drive units 207a and 207b are all turned off, the drive voltage applied to the solenoid 407 is reduced, and the drive current flowing is also reduced. Then, the valve body moves in the valve closing direction, and the fuel injection valve 105 is closed. As a result, no fuel is injected from the fuel injection valve 105.

[0079] Furthermore, from time T404 when the injection pulse is turned off, the boost voltage 210 is supplied in the opposite direction to that when the fuel injection valve 105 is driven, so that the residual magnetism in the fuel injection valve 105 is quickly demagnetized, thereby closing the fuel injection valve 105 early.

[0080] [Split injection control]

[0081] Next, refer to Figure 5 The split injection control will be described.

[0082] Figure 5 This is a diagram for explaining the single injection control and the split injection control. Figure 5, the waveform of the injection pulse 511 when switching from the single injection control to the split injection control is shown, and the injection pulses of the n to (n+3) cylinders are injection pulses 511a to 511d, respectively. The time T501 in the figure indicates the time point when the split injection control is permitted (for example, the split injection number changes from 1 to 3).

[0083] First, in order to drive the fuel injection valve 105 based on a specified crank angle, as a general method of angle control, a control reference position (T508a~T508d) is set for each cylinder, and the control timing of the fuel injection valve 105 is measured at a desired angle based on the control reference position.

[0084] When based on this Figure 5 For the purpose of explanation, at a time later than time T501 (to the left of time T501), split injection control is not performed, but one injection is performed. At time T508d, the injection pulse T502 of the (n+3) cylinder is output, and at time T508a, the injection pulse 503 of the n cylinder is output. That is, one fuel injection is performed in one combustion cycle. Furthermore, with respect to the control reference position (time T501), the injection pulse 504 of the (n+1) cylinder in the future (to the right of time T501) is located on the left side, and since the injection control is performed at the injection start time 509 at this time point, this is also a one injection.

[0085] From the time T508b when the initial control reference position is reached from the time T501, the injection instruction 505 (the divided injection instructions 505a, 505b, 505c) is generated at the injection start time 510 for the divided injection. Therefore, the divided injection is executed after the injection start time 510. After that, the divided injection control is continuously performed, and the same control as the injection instruction 505 is performed, thereby the injection instructions 506 and the injection instructions 507 also execute the divided injection.

[0086] also, Figure 5 The split injection control is shown as being executed with three injections (eg, split injection instructions 505a to 505c), but even when the number of times is different, the basic control method does not change.

[0087] In addition, split injection is defined as at least two fuel injections in one combustion cycle. One combustion cycle refers to 720 degrees during the combustion stroke (intake, compression, expansion, exhaust) of a four-stroke internal combustion engine, although the position (angle) is different in each cylinder. However, the object of abnormality judgment of the split injection function of the present invention is not limited to split injection, but also includes the case where one fuel injection is performed in one combustion cycle.

[0088] [Abnormal state of split injection]

[0089] Next, an abnormal state of divided injection will be described.

[0090] The abnormal state refers to a state in which fuel injection is not performed according to the injection command, such as “fuel injection is not performed”, “fuel injection is performed without a command value”, and “timing of fuel injection is offset from the command value”.

[0091] The abnormality of "fuel injection is not executed" indicates, for example, that fuel injection is not executed due to an abnormality between the fuel injection pulse signal operation unit 202 and the fuel injection valve 105 for the injection parameters calculated by the split injection control instruction unit 201. That is, it indicates a state where no voltage is applied to the fuel injection valve 105 (solenoid 407) and no current flows through the fuel injection valve 105. However, it also includes a situation where the fuel injection valve drive state detection unit 211 cannot detect the current even though the fuel injection valve 105 is passed with current, such as a short circuit to the ground (ground) on the downstream side of the fuel injection valve 105.

[0092] The abnormality of “fuel injection executed without command value” means that voltage is applied to the fuel injection valve 105 and current flows through the fuel injection valve 105 even though there is no fuel injection request (for example, the requested injection amount is zero) in the split injection control command unit 201 .

[0093] That is, the abnormalities of "fuel injection is not performed" and "fuel injection is performed despite no command value" are respectively states in which divided injection is not performed according to the number of injection commands.

[0094] The abnormality of "the timing of fuel injection is offset relative to the instruction value" is that voltage is applied to the fuel injection valve 105 earlier (offset in the direction of the advance angle) or later (offset in the direction of the retard angle) than the requested injection timing calculated by the split injection control instruction unit 201, and current flows through the fuel injection valve 105.

[0095] [Fuel injection valve driving state detection unit]

[0096] Next, refer to Figure 6 The fuel injection valve driving state detection unit 211 will be described.

[0097] Figure 6 1 is a timing chart for explaining a drive current detection signal of the fuel injection valve 105 .

[0098] The fuel injection valve driving state detection unit 211 detects whether the fuel injection valve 105 performs fuel injection. The fuel injection pulse signal calculation unit 202 outputs an injection pulse for each injection. Then, the high voltage generation unit 206 or the battery voltage generation unit 209 applies a voltage to the fuel injection valve 105, and a current flows, thereby performing fuel injection.

[0099] like Figure 6 As shown, in the fuel injection pulse signal calculation unit 202, the injection pulse INJPLS is turned on from the injection start time INJSOI calculated by the split injection control instruction unit 201. When the injection pulse is turned on, a high level signal (T601) is transmitted to the driver IC 208, and current is passed to the fuel injection valve 105. Then, after a predetermined injection time, when the injection output is stopped, a low level signal (T602) is transmitted to the driver IC 208.

[0100] In the fuel injection valve drive state detection unit 211, for example, the drive current flowing through the fuel injection valve 105 (solenoid 407) is measured using the shunt resistor 306 to generate a drive current detection signal INJDET. Here, the drive current detection signal INJDET is a signal indicating whether the drive current is supplied to the fuel injection valve 105. The fuel injection valve drive state detection unit 211 outputs the generated drive current detection signal INJDET to the split injection abnormality detection unit 213.

[0101] The fuel injection valve drive state detection unit 211 sets the drive current detection signal INJDET to a High level (T603) when the drive current flowing through the fuel injection valve 105 becomes greater than a specified value (signal on threshold), and sets it to a Low level (T604) when the drive current becomes less than a specified value (signal off (OFF) threshold).

[0102] In addition, the prescribed value for changing the drive current detection signal INJDET to the High level or the Low level is obtained in advance through experiments or the like, and is set in the memory 142. When the drive current (for example, the peak current value) is changed based on the fuel pressure, the prescribed value for changing the drive current detection signal INJDET to the High level may be changed according to the fuel pressure, or the prescribed value may be set to be less than the minimum value of the peak current value under each fuel pressure condition.

[0103] In addition, the drive current detection signal INJDET can be either High or Low as long as the logic is reversed. Hereinafter, the drive current detection signal INJDET is turned on (High level) when power is detected, and turned off (Low level) when power is not detected.

[0104] [Division injection abnormality detection unit]

[0105] Next, refer to Figure 7 The divided injection abnormality detecting unit 213 will be described.

[0106] Figure 7 This is a timing chart for explaining the operation of the split injection abnormality detection unit 213 . The injection start timing INJSOI_TRG is a target injection start timing output from the split injection control instruction unit 201 , and the injection pulse INJPLS_OUT is an injection pulse signal output from the fuel injection pulse signal calculation unit 202 .

[0107] The split injection abnormality detection unit 213 performs the above-mentioned split injection abnormality detection. The split injection abnormality detection unit 213 compares the injection start time INJSOI_TRG calculated by the split injection control instruction unit 201 with the drive current detection signal INJDET generated by the fuel injection valve drive state detection unit 211, and determines whether there is an abnormality based on the difference between the two. In addition, the abnormality detection process is performed on all the generated injection pulses.

[0108] As described above, the information of the injection start time INJSOI_TRG and the fuel injection amount calculated by the split injection control instruction unit 201 is transmitted to the fuel injection pulse signal calculation unit 202, and the fuel injection amount is converted into the injection pulse width (power-on time). When the engine rotates and the crank angle becomes the angle of the injection start time INJSOI_TRG, the fuel injection pulse signal calculation unit 202 turns the injection pulse INJPLS_OUT to the on state and outputs it to the driver IC 208 (T701). According to the injection pulse INJPLS_OUT, a driving current is passed to the fuel injection valve 105, and the driving current is measured in the fuel injection valve driving state detection unit 211. When the current value becomes greater than the specified value, the driving current detection signal INJDET is turned on. In the fuel injection valve driving state detection unit 211, the time when the driving current detection signal INJDET becomes ON is stored. Here, the so-called time refers to the crank angle based on the injection start time INJSOI_TRG and the control reference position.

[0109] The drive current detection signal INJDET measures the current flowing through the fuel injection valve 105, but due to the influence of the inductance of the fuel injection valve 105 (solenoid 407), the current rises with a hysteresis (delay) corresponding to the time constant. Therefore, even if there is no abnormality, the time when the drive current detection signal INJDET is turned on (the rising time) is delayed relative to the injection start time INJSOI_TRG. In this way, even in normal conditions, a time difference occurs between the injection start time INJSOI_TRG and the time when the drive current detection signal INJDET is turned on.

[0110] According to the above reasons, when detecting abnormality, it is determined whether the difference between the injection start time INJSOI_TRG and the time when the drive current detection signal INJDET is turned on is within the prescribed range 703. When the drive current detection signal INJDET is turned on within the prescribed range 703 from the injection start time INJSOI_TRG, it is determined to be "normal", and when the drive current detection signal INJDET is not turned on within the prescribed range 703, it is determined to be "abnormal".

[0111] In addition, the hysteresis of the timing when the driving current detection signal INJDET is turned on is determined by the voltage applied to the fuel injection valve 105, the temperature, resistance, and inductance of the fuel injection valve 105. That is, even if there are errors in the constants and voltage values ​​of the circuit elements, the range of the injection abnormality diagnosis will not be wrongly divided, and it is preferably determined in advance by experiments and stored in the memory 142.

[0112] As described above, the injection abnormality detection unit (split injection abnormality detection unit 213) compares the target output timing (injection start timing INJSOI_TRG) of the injection pulse signal based on the fuel injection instruction and the rising timing (also called rising edge timing) of the drive current detection signal (drive current detection signal INJDET) indicating the drive state of the fuel injection valve output from the drive state detection unit (fuel injection valve drive state detection unit 211), and detects the injection abnormality of the fuel injection valve based on the difference between the two timings.

[0113] [Method for detecting abnormality of split injection]

[0114] Next, use Figure 8 A method of detecting a split injection abnormality will be described.

[0115] Figure 8 This is a diagram for explaining an abnormal state that can be detected by the divided injection abnormality detection unit 213. The dotted line represents a waveform when the injection is normal, and the solid line represents a waveform when the injection is abnormal.

[0116] The abnormality of "fuel injection not executed" is a situation where the drive current detection signal INJDET does not become on within the specified range 703 from the injection start time INJSOI_TRG, although there is a fuel injection command in the split injection control command unit 201 (for example, the fuel injection amount is not zero). It is a situation where the injection pulse INJPLS_OUT is not output due to an abnormality in the fuel injection pulse signal calculation unit 202, and the fuel injection valve 105 is not supplied with current due to an abnormality in the drive circuit, an abnormality in the fuel injection valve 105, etc. Therefore, the current cannot be measured by the fuel injection valve drive state detection unit 211, and the drive current detection signal INJDET is not turned on ( Figure 8 The driving circuit includes, for example, a frame and wiring after the driving IC 208.

[0117] The abnormality of "fuel injection is executed without command value" is a case where the drive current detection signal INJDET is turned on even though there is no fuel injection command in the split injection control command unit 201 (for example, the requested injection amount is zero). It is a case where the injection pulse INJPLS_OUT is output due to an abnormality in the fuel injection pulse signal calculation unit 202, and a case where current is passed to the fuel injection valve 105 due to an abnormality in the drive circuit ( Figure 8 In this case, abnormality detection can be performed by comparing the injection start time INJSOI_TRG of the previous injection with the time when the drive current detection signal INJDET turns on.

[0118] The abnormality of "the timing of fuel injection is offset from the command value" occurs when the drive current is supplied to the fuel injection valve 105 earlier or later than the injection start timing INJSOI_TRG commanded by the split injection control command unit 201. The drive current detection signal INJDET is turned on earlier than the injection start timing INJSOI_TRG ( Figure 8 Lower left), or the drive current detection signal INJDET becomes on later than the prescribed range 703 ( Figure 8 The timing of supplying the drive current to the fuel injection valve 105 changes due to abnormality in the fuel injection pulse signal calculation unit 202, abnormality in the drive circuit, etc.

[0119] By judging the above state (abnormality) for each injection pulse and each drive current detection signal INJDET, the detection of split injection abnormality can be performed. In addition, each information can be temporarily stored in the memory 142 (RAM, etc.), and the judgment of split injection abnormality can be implemented at a certain interval such as each control reference position.

[0120] For example, the injection start timing INJSOI_TRG corresponding to the number of injections in one combustion cycle at the control reference position or the like is stored in advance (three injection start timings INJSOI_TRG in the case of three-part injection). Furthermore, whenever the drive current detection signal INJDET is also turned on, the timing information (time, angle) at which the turn-on is made is stored in the RAM. Furthermore, if they are compared at the next control reference position, it is not necessary to process them one by one, and it is possible to distinguish between an advance angle abnormality and an increase abnormality.

[0121] [Divided injection abnormality detection execution judgment unit]

[0122] Next, refer to Fig. 9 The divided injection abnormality detection execution determination unit 212 will be described.

[0123] The split injection abnormality detection execution judgment unit 212 judges whether the split injection abnormality detection unit 213 can be executed. When the split injection abnormality detection execution judgment unit 212 judges that it can be executed, the split injection abnormality detection unit 213 executes the split injection abnormality detection. The split injection abnormality detection unit 213 judges that it is "abnormal" when the difference between the injection start time INJSOI_TRG and the time when the drive current detection signal INJDET is turned on is large, and judges that it is "normal" when the difference between the two is small.

[0124] On the other hand, when it is determined that the operation is not executable, the injection start timing INJSOI_TRG and the time when the drive current detection signal INJDET is turned on are detected, and even if the difference between the two is greater than the prescribed range 703, it is not determined to be abnormal. In addition, even if the difference between the two is small enough to be within the prescribed range 703, it is not determined to be normal. In addition, the process of comparing the difference between the two may not be executed.

[0125] As described above, even if the split injection function is not abnormal, the timing at which the drive current detection signal INJDET turns on may not be within the predetermined range 703 from the injection start timing INJSOI_TRG. In this case, the split injection abnormality detection unit 213 may determine that the split injection function is abnormal even if the split injection function is not abnormal.

[0126] Therefore, in the divided injection abnormality detection execution determination unit 212, control is performed to detect a situation where there is a possibility of determining that the divided injection function is abnormal even though the divided injection function is in a normal state, thereby avoiding erroneous abnormality determination.

[0127] (Division injection abnormality judgment based on injection interval)

[0128] First, refer to Fig. 9 The divided injection abnormality determination based on the injection interval will be described.

[0129] Fig. 9 This is a timing chart for explaining the case where the split injection abnormality determination is not performed based on the injection interval. The dotted line represents the waveform when the injection interval is short, and the solid line represents the waveform when the injection interval is long.

[0130] The injection interval is determined by taking into account the valve closing time of the fuel injection valve 105 and the boost voltage charging time. The injection start time INJSOI_TRG and the fuel injection amount calculated by the split injection control instruction unit 201 are converted into an injection pulse width and output from the fuel injection pulse signal calculation unit 202 to the driver IC 208. At this time, when the interval between the OFF time of the last injection pulse width and the current injection start time INJSOI_TRG#2 is shorter than the preset injection interval 901, the injection start time INJSOI_TRG#2 is shifted to the lag angle side and used as the injection start time INJSOI_OUT#2 so that the interval becomes longer than the injection interval 901. In this way, the fuel injection delay caused by the start of power-on when the boost voltage 210 is reduced and the combination (overlap) with the previous fuel injection can be avoided.

[0131] However, since the actual injection start time is delayed relative to the injection start time INJSOI_TRG calculated by the split injection control instruction unit 201, the time (timing, also called timing) when the drive current detection signal INJDET is turned on is also delayed. Therefore, the turn-on time of the drive current detection signal INJDET is not within the prescribed range 703 from the injection start time INJSOI_TRG, and it may be judged as abnormal. Therefore, when the turn-on time of the injection pulse INJSOI_TRG is delayed by adjusting the injection interval, the abnormality judgment of the split injection function is not implemented.

[0132] In addition, the faster the speed of the engine (internal combustion engine 101), the shorter the injection interval. Therefore, when the speed of the internal combustion engine is greater than a predetermined value, the injection abnormality detection execution judgment unit (injection abnormality detection execution judgment unit 212) may not cause the injection abnormality detection unit (split injection abnormality detection unit 213) to perform injection abnormality detection.

[0133] As described above, in the fuel injection control device (fuel injection control device 127) of the present embodiment, the injection abnormality detection execution judgment unit (injection abnormality detection execution judgment unit 212) is configured such that when the interval (injection interval 901) between the target stop time of the injection pulse signal of the previous injection and the target output time (injection start time INJSOI_TRG) of the injection pulse signal of this injection is shorter than a specified value, the injection abnormality detection is not performed using the injection abnormality detection unit (split injection abnormality detection unit 213).

[0134] (Division injection abnormality judgment based on injection pulse width)

[0135] Next, refer to Fig.10 The split injection abnormality determination based on the injection pulse width will be described.

[0136] The injection pulse width calculated by the fuel injection pulse signal calculation unit 202 is calculated based on the fuel injection amount calculated by the split injection control command unit 201. Since the injection pulse width is the power-on time of the fuel injection valve 105, if the power-on time is long, that is, the injection pulse width is long, the fuel injection amount is large, and if the injection pulse width is short, the fuel injection amount is small. Therefore, when the fuel injection amount is small, the injection pulse width is short.

[0137] In addition, the fuel injection amount also changes according to the fuel pressure. The higher the fuel pressure, the greater the fuel injection amount per unit time. Therefore, in general, in order to meet the requested fuel injection amount, the injection pulse width is changed according to the fuel pressure. That is, for the requested fuel injection amount, the injection pulse width is controlled in such a way that the higher the fuel pressure, the shorter the injection pulse width.

[0138] Fig.10 This is a timing chart for explaining the case where the split injection abnormality determination is not performed based on the injection pulse width. The dotted line represents the waveform when the injection pulse width is long, and the solid line represents the waveform when the injection pulse width is short.

[0139] like Fig.10 As shown, when the injection pulse width is short, the power supply to the fuel injection valve 105 may be stopped before the drive current reaches the signal ON threshold. At the injection start time INJSOI_TRG#2, the injection pulse is output, and the drive current starts to be supplied to the fuel injection valve 105. When the output of the injection pulse is stopped at time T1001, the power supply to the fuel injection valve 105 is stopped. Because the power supply is stopped before the drive current reaches the signal ON threshold, the drive current power supply signal INJDET will not be turned on. Because the drive current power supply signal INJDET is not turned on within the specified range 703 from the injection start time INJSOI_TRG, it is judged to be abnormal even though there is no abnormality in the split injection function.

[0140] Therefore, when the injection pulse width is shorter than the predetermined value 1002, the abnormality determination of the split injection function is not performed. The predetermined value 1002 is equal to or longer than the time from the injection start time INJSOI_TRG to the time when the drive current energization signal INJDET is turned on. The predetermined value 1002 is calculated in advance by experiments and stored in the memory 142.

[0141] As described above, in the fuel injection control device (fuel injection control device 127) of the present embodiment, the injection abnormality detection execution judgment unit (injection abnormality detection execution judgment unit 212) is configured so that when the width of the injection pulse signal (injection pulse width) serving as the power-on time instruction of the fuel injection valve is shorter than a specified value, the injection abnormality detection unit (split injection abnormality detection unit 213) does not perform injection abnormality detection.

[0142] (Split injection abnormality judgment based on boost voltage)

[0143] Next, refer to Fig.11 The split injection abnormality determination based on the boosted voltage 210 will be described.

[0144] When the boost voltage 210 is low, the time from when the drive current starts to flow to the fuel injection valve 105 until the peak current is reached becomes longer. For example, when the engine speed is high or the number of split injections is large, the injection interval with other cylinders becomes short, which disrupts the charge and discharge balance of the boost voltage 210, and fuel injection may be started when the boost voltage 210 is low. The same is true when the boost voltage 210 cannot be supplied due to a failure of the high voltage generator 206 or the like.

[0145] Furthermore, when a failure occurs in the high voltage generating unit 206 , the high voltage is supplied from the battery voltage 209 , so it takes time for the drive current to increase.

[0146] Fig.11 This is a timing chart for explaining a case where the split injection abnormality determination is not performed based on the boosted voltage 210. The dotted line shows a waveform when the boosted voltage 210 is high, and the solid line shows a waveform when the boosted voltage 210 is low.

[0147] When the injection pulse is output from the injection start time INJSOI_TRG, a voltage is applied to the fuel injection valve 105, and the drive current starts to flow. However, since the boost voltage 210 is low, the rising speed of the drive current is slow, and the current value reaches the signal ON threshold slowly. For example, when the boost voltage 210 is high, it becomes the time T1101, and when the boost voltage 210 is low, it becomes the late time T1102. Therefore, the time when the drive current detection signal INJDET becomes turned on is not within the prescribed range 703 from the injection start time INJSOI_TRG#2, and it is determined that the split injection function is abnormal.

[0148] Therefore, when the voltage (boosted voltage 210) applied to the fuel injection valve 105 is equal to or less than a predetermined value, or when the booster device is determined to be abnormal, the abnormality determination of the split injection function is not performed.

[0149] As described above, in the fuel injection control device (fuel injection control device 127) of the present embodiment, the injection abnormality detection execution judgment unit (injection abnormality detection execution judgment unit 212) is configured such that when the voltage applied to the fuel injection valve is below a specified value, the injection abnormality detection performed by the injection abnormality detection unit (divided injection abnormality detection unit 213) is not performed.

[0150] In addition, as one of the information indicating the engine state, there is the temperature of the cooling water. When the temperature of the cooling water measured by the water temperature sensor 108 is high, the temperature of the internal combustion engine 101 is high, and the resistance value of the drive circuit becomes small, so the boost voltage 210 may decrease. Therefore, when the temperature of the cooling water is higher than the threshold value, it is also preferable not to perform the abnormality judgment of the split injection function.

[0151] Thus, in the present embodiment, the injection abnormality detection execution judgment unit (injection abnormality detection execution judgment unit 212) is configured such that when the measurement value of the water temperature sensor 108 measuring the cooling water temperature of the internal combustion engine is greater than a prescribed value, the injection abnormality detection performed by the injection abnormality detection unit (divided injection abnormality detection unit 213) is not performed.

[0152] (Division injection abnormality judgment based on forced end time)

[0153] Next, refer to Fig.12 and Fig.13 The split injection abnormality determination based on the forced end timing of the fuel injection will be described.

[0154] When the injection start time INJSOI_TRG is set before the valve closing completion time of the exhaust valve 104, the fuel injected from the fuel injection valve 105 is discharged to the exhaust pipe 111 without burning, and the exhaust performance deteriorates. In addition, when the moment when the injection pulse is disconnected is close to the ignition moment, the vaporization time of the injected fuel cannot be fully ensured, and the formation of the mixed gas becomes insufficient. In this case, the fuel may adhere to the spark plug 106. Therefore, the injection action is usually completed from the ignition moment to the position (forced end time T1201) set for a predetermined period on the advance angle side in consideration of the vaporization time of the fuel.

[0155] However, in transient conditions such as an increase in the number of injection divisions, the above-mentioned injection interval, and a sudden change in engine rotation, the fuel injection end time will be delayed. Therefore, in the case where the injection pulse signal continues to be in the on state after the forced end time T1201, and the injection start time INJSOI_TRG becomes after the forced end time T1201, the injection pulse is turned off at the forced end time T1201. Therefore, although a fuel injection request is transmitted from the split injection control instruction unit 201, it is possible that fuel injection is not performed. In this case, the drive current detection signal INJDET will not be turned on.

[0156] Fig.12 A timing diagram showing a case where the split injection abnormality judgment is not performed according to the forced end timing (part 1). The dotted line shows the waveform to be output. Fig.12 In the example, the second injection start timing INJSOI_TRG#2 is after the forced end timing T1201. Therefore, the injection pulse INJPLS_OUT is not output from the fuel injection pulse signal calculation unit 202, and the drive current detection signal INJDET is not turned on.

[0157] Fig.13 A timing diagram showing a case where the split injection abnormality judgment is not performed according to the forced end timing (part 2). The dotted line shows the waveform to be output, and the solid line shows the waveform actually output. Fig.13 In this embodiment, the injection end time (T1301) of the injection pulse INJPLS_OUT output at the second injection start time INJSOI_TRG#2 is after the forced end time T1201. Therefore, the injection pulse INJPLS_OUT is turned off at the forced end time T1201, and the drive current detection signal INJDET is not turned on.

[0158] Therefore, when the injection pulse is turned on or when there is a forced end timing T1201 before the injection start timing INJSOI_TRG, the abnormality determination of the divided injection function is not performed.

[0159] As described above, the injection abnormality detection execution judgment unit (split injection abnormality detection execution judgment unit 212) is configured to not execute the injection abnormality detection performed by the injection abnormality detection unit (split injection abnormality detection unit 213) when the crank angle of at least one of the target output time (injection start time INJSOI_TRG) of the injection pulse signal and the target stop time is greater than the specified rotation angle (rotation angle) from the control reference position of the internal combustion engine. Here, the so-called specified rotation angle of the crank angle is the time when the crankshaft 131 rotates from the control reference position by a specified angle, which is equivalent to the forced end time T1201.

[0160] (Divided injection abnormality determination during fuel cut)

[0161] Next, the divided injection abnormality determination during the fuel cut period will be described.

[0162] The fuel cut-off process is performed when a vehicle equipped with an internal combustion engine decelerates or when a part related to fuel injection fails. Usually, various information required for fuel cut-off is collected, and a fuel cut-off command is output from a control command unit (not shown) different from the split injection control command unit 201 to the fuel injection pulse signal operation unit 202 to stop fuel injection. In addition, a fuel cut-off request may be output to the split injection control command unit 201, and the split injection control command unit 201 makes the requested injection amount zero. That is, because the drive current detection signal INJDET does not become turned on when the injection pulse INJPLS_OUT becomes zero during the on period, the abnormality judgment of the split injection function is not implemented.

[0163] Thus, the injection abnormality detection execution determination unit (divided injection abnormality detection execution determination unit 212) is configured not to execute the injection abnormality detection by the injection abnormality detection unit (divided injection abnormality detection unit 213) when de-energization of the fuel injection valve is instructed.

[0164] However, as described above, although erroneous abnormality determination can be avoided for abnormalities such as "fuel injection not being performed" or "fuel injection timing being offset from the command value", abnormality detection cannot be performed for failures such as "fuel injection being performed without a command value".

[0165] Therefore, the abnormality judgment at the time of fuel cut is not to compare the injection start time INJSOI_TRG with the time when the drive current detection signal INJDET turns on, but to detect whether the drive current detection signal INJDET turns on at the time of fuel cut. In this way, the abnormality judgment can be correctly performed for the fault of "fuel injection is executed without a command value".

[0166] In this way, the injection abnormality detection unit (divided injection abnormality detection unit 213) is constructed so that when the power supply to the fuel injection valve is instructed to stop, when the drive current detection signal (drive current detection signal INJDET) of the fuel injection valve output from the drive state detection unit (fuel injection valve drive state detection unit 211) becomes turned on during the period when the power supply to the fuel injection valve is stopped, it is judged that there is an injection abnormality in the fuel injection valve.

[0167] As described above, the fuel injection control device (fuel injection control device 127) of the present embodiment is a fuel injection control device that controls multiple fuel injection valves (105) having energized coils, and includes: a fuel injection pulse output unit (fuel injection pulse signal operation unit 202), which outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection instruction; a drive state detection unit (fuel injection valve drive state detection unit 211), which detects the drive state of the fuel injection valve based on the energized current or applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit (split injection abnormality detection unit 213), which detects the injection abnormality of the fuel injection valve by comparing the fuel injection instruction with the drive state of the fuel injection valve; and an injection abnormality detection execution judgment unit (split injection abnormality detection execution judgment unit 212), which judges whether the injection abnormality detection can be performed by the injection abnormality detection unit based on the state of the internal combustion engine, and if it is judged that it is not executable, the injection abnormality detection performed by the injection abnormality detection unit is not performed.

[0168] According to the fuel injection control device of the present embodiment of the above-mentioned structure, the following control is performed: in the abnormal judgment of judging whether the fuel injection valve has normally performed fuel injection, based on the state of the internal combustion engine, it is detected that although the injection function (such as the split injection function) is in a normal state, it is possible to judge that the injection function is abnormal, thereby avoiding erroneous abnormal judgments. As a result, in the abnormal judgment of the injection function, erroneous judgments can be prevented. Therefore, the abnormality of the injection function can be correctly judged, and the deterioration of exhaust performance and the torque variation of the internal combustion engine caused by erroneous abnormal judgments (or normal judgments) can be avoided.

[0169] In addition, in the fuel injection control device (fuel injection control device 127) of the present embodiment, the so-called state of the above-mentioned internal combustion engine (internal combustion engine 101) refers to the driving state of the fuel injection valve (fuel injection valve 105), at least any one of the interval of continuous injection pulse signals (injection interval 901), the width of the injection pulse signal, the voltage applied to the coil (solenoid 407) (boost voltage 210), and the rising time (injection start time INJSOI_TRG) or falling time of the injection pulse signal.

[0170] In the fuel injection control device (fuel injection control device 127) of the present embodiment, the state of the internal combustion engine (internal combustion engine 101) is at least one of the rotation speed and the temperature of the internal combustion engine.

[0171] <Modification>

[0172] An embodiment of the fuel injection control device of the present invention including its effects has been described above. However, the present invention is not limited to the above embodiment, and other various application examples and modified examples are possible as long as they do not deviate from the purpose of the present invention described in the claims.

[0173] For example, the above-mentioned one embodiment is an embodiment that describes the structure of the fuel injection control device in detail and specifically for the purpose of explaining the present invention in a simple and understandable manner, and is not necessarily limited to having all the components described. In addition, other components may be added, replaced or deleted with respect to a part of the structure of one embodiment.

[0174] In addition, the above-mentioned structures, functions, processing units, etc. may be partially or entirely implemented by hardware, for example, by designing with integrated circuits, etc. As hardware, FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) may be used.

[0175] Description of Reference Numerals

[0176] 101…Internal combustion engine

[0177] 105…Fuel injection valve

[0178] 109…ECU

[0179] 127…Fuel injection control device

[0180] 201…Split injection control command unit

[0181] 202…Fuel injection pulse signal calculation unit

[0182] 203…Fuel injection drive waveform command unit

[0183] 211 ...Fuel injection valve driving state detection unit

[0184] 212 ...Division injection abnormality detection execution judgment unit

[0185] 213 ...Division injection abnormality detection unit

[0186] 214…Engine status detection unit

[0187] 407…Solenoid

Claims

1. A fuel injection control device for controlling a plurality of fuel injection valves having energizing coils, the fuel injection control device comprising: a fuel injection pulse output unit that outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection command; a driving state detecting unit for detecting a driving state of the fuel injection valve based on a current or an applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit for detecting an injection abnormality of the fuel injection valve by comparing the fuel injection command with a driving state of the fuel injection valve; and an injection abnormality detection execution determination unit that determines whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is determined that the injection abnormality detection cannot be executed. The state of the internal combustion engine is the driving state of the fuel injection valve, at least one of the interval between continuous injection pulse signals, the width of the injection pulse signal, the voltage applied to the coil, and the rising time or falling time of the injection pulse signal, The injection abnormality detection execution determination unit does not execute the injection abnormality detection by the injection abnormality detection unit when the interval between the target stop timing of the injection pulse signal of the previous injection and the target output timing of the injection pulse signal of the current injection is shorter than a predetermined value.

2. A fuel injection control device for controlling a plurality of fuel injection valves having energizing coils, the fuel injection control device comprising: a fuel injection pulse output unit that outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection command; a driving state detecting unit for detecting a driving state of the fuel injection valve based on a current or an applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit for detecting an injection abnormality of the fuel injection valve by comparing the fuel injection command with a driving state of the fuel injection valve; and an injection abnormality detection execution determination unit that determines whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is determined that the injection abnormality detection cannot be executed. The state of the internal combustion engine is the driving state of the fuel injection valve, at least one of the interval between continuous injection pulse signals, the width of the injection pulse signal, the voltage applied to the coil, and the rising time or falling time of the injection pulse signal, The injection abnormality detection execution determination unit does not execute the injection abnormality detection by the injection abnormality detection unit when a width of an injection pulse signal serving as an energization time command for the fuel injection valve is shorter than a predetermined value.

3. A fuel injection control device for controlling a plurality of fuel injection valves having energizing coils, the fuel injection control device comprising: a fuel injection pulse output unit that outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection command; a driving state detecting unit for detecting a driving state of the fuel injection valve based on a current or an applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit for detecting an injection abnormality of the fuel injection valve by comparing the fuel injection command with a driving state of the fuel injection valve; and an injection abnormality detection execution determination unit that determines whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is determined that the injection abnormality detection cannot be executed. The state of the internal combustion engine is the driving state of the fuel injection valve, at least one of the interval between continuous injection pulse signals, the width of the injection pulse signal, the voltage applied to the coil, and the rising time or falling time of the injection pulse signal, The injection abnormality detection execution determination unit does not execute the injection abnormality detection by the injection abnormality detection unit when the voltage applied to the fuel injection valve is equal to or less than a predetermined value.

4. A fuel injection control device for controlling a plurality of fuel injection valves having energizing coils, the fuel injection control device comprising: a fuel injection pulse output unit that outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection command; a driving state detecting unit for detecting a driving state of the fuel injection valve based on a current or an applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit for detecting an injection abnormality of the fuel injection valve by comparing the fuel injection command with a driving state of the fuel injection valve; and an injection abnormality detection execution determination unit that determines whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is determined that the injection abnormality detection cannot be executed. The state of the internal combustion engine is the driving state of the fuel injection valve, at least one of the interval between continuous injection pulse signals, the width of the injection pulse signal, the voltage applied to the coil, and the rising time or falling time of the injection pulse signal, The injection abnormality detection execution judgment unit does not execute the injection abnormality detection performed by the injection abnormality detection unit when the crank angle of at least one of the target output timing and the target stop timing of the injection pulse signal is greater than a specified rotation angle from a control reference position of the internal combustion engine.

5. A fuel injection control device for controlling a plurality of fuel injection valves having energizing coils, the fuel injection control device comprising: a fuel injection pulse output unit that outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection command; a driving state detecting unit for detecting a driving state of the fuel injection valve based on a current or an applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit for detecting an injection abnormality of the fuel injection valve by comparing the fuel injection command with a driving state of the fuel injection valve; and an injection abnormality detection execution determination unit that determines whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is determined that the injection abnormality detection cannot be executed. The state of the internal combustion engine is the driving state of the fuel injection valve, at least one of the interval between continuous injection pulse signals, the width of the injection pulse signal, the voltage applied to the coil, and the rising time or falling time of the injection pulse signal, The injection abnormality detection execution determination unit does not execute the injection abnormality detection by the injection abnormality detection unit when de-energization of the fuel injection valve is instructed.

6. The fuel injection control device according to any one of claims 1 to 5, characterized in that: When de-energization of the fuel injection valve is instructed, the injection abnormality detection unit determines that an injection abnormality has occurred in the fuel injection valve when a drive current detection signal of the fuel injection valve output from the drive state detection unit becomes on during de-energization of the fuel injection valve.

7. A fuel injection control device for controlling a plurality of fuel injection valves having energizing coils, the fuel injection control device comprising: a fuel injection pulse output unit that outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection command; a driving state detecting unit for detecting a driving state of the fuel injection valve based on a current or an applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit for detecting an injection abnormality of the fuel injection valve by comparing the fuel injection command with a driving state of the fuel injection valve; and an injection abnormality detection execution determination unit that determines whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is determined that the injection abnormality detection cannot be executed. The state of the internal combustion engine is at least one of a rotation speed and a temperature of the internal combustion engine, and the injection abnormality detection execution determination unit does not execute the injection abnormality detection performed by the injection abnormality detection unit when the rotation speed of the internal combustion engine is greater than a predetermined value.

8. A fuel injection control device for controlling a plurality of fuel injection valves having energizing coils, the fuel injection control device comprising: a fuel injection pulse output unit that outputs an injection pulse signal for driving the fuel injection valve based on a fuel injection command; a driving state detecting unit for detecting a driving state of the fuel injection valve based on a current or an applied voltage of the coil of the fuel injection valve; an injection abnormality detection unit for detecting an injection abnormality of the fuel injection valve by comparing the fuel injection command with a driving state of the fuel injection valve; and an injection abnormality detection execution determination unit that determines whether the injection abnormality detection performed by the injection abnormality detection unit can be executed based on the state of the internal combustion engine, and does not execute the injection abnormality detection performed by the injection abnormality detection unit if it is determined that the injection abnormality detection cannot be executed. The state of the internal combustion engine is at least one of the rotation speed and the temperature of the internal combustion engine. The injection abnormality detection execution determination unit does not execute the injection abnormality detection performed by the injection abnormality detection unit when a measurement value of a water temperature sensor measuring a temperature of cooling water of the internal combustion engine is equal to or greater than a predetermined value.

9. The fuel injection control device according to any one of claims 1 to 5, 7 and 8, characterized in that: The injection abnormality detection unit compares the target output timing of the injection pulse signal based on the fuel injection instruction with the rising timing of the drive current detection signal of the fuel injection valve output from the drive state detection unit, and detects the injection abnormality of the fuel injection valve based on the difference between the two timings.

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