DEVICE FOR CONTROLLING FUEL INJECTION AND METHOD FOR CONTROLLING FUEL INJECTION

Abstract

Fuel injection control device, comprising: a first power supply unit that provides a first voltage; a second power supply unit that provides a second voltage that is higher than the first voltage; a fuel injection control unit that controls the second voltage supply unit to supply the second voltage to a coil to open a fuel injection valve having the coil, and that controls the first voltage supply unit to supply the first voltage to the coil to maintain a valve opening state of the fuel injection valve; a voltage measuring unit that measures and outputs voltage information based on an upstream voltage of the coil of the fuel injection valve and a downstream voltage of the coil; a correction unit that corrects the fuel injection quantity of the fuel injection valve based on the voltage information output by the voltage measuring unit; and an anomaly detection unit that detects whether an output of the voltage measuring unit is abnormal, based on the voltage information output by the voltage measuring unit.

Description

Technical field

[0001] The present invention relates to a fuel injection control device or the like, which controls a fuel injection valve that supplies fuel to an internal combustion engine. State of the art

[0002] Due to the tightening of fuel consumption and emissions regulations for motor vehicles in recent years, there is a need to simultaneously achieve low fuel consumption and high performance from an internal combustion engine, while also adapting to a wide operating range. One method to achieve this is by extending the dynamic range of a fuel injection valve.

[0003] To extend the dynamic range of the fuel injection valve, the dynamic flow characteristics must be improved while simultaneously maintaining the conventional static flow characteristics. Reducing the minimum injection quantity through half-stroke control is a known method for improving the dynamic flow characteristics.

[0004] In this half-stroke control system, highly precise control is achieved in a state (half-stroke range) before the valve body of a fuel injection valve fully reaches an open position (full stroke position). However, it is known that the injection quantity fluctuates considerably in the half-stroke range due to individual differences between fuel injection valves. That is, even if the respective fuel injection valves are actuated with the same pulse width (control pulse for opening and closing the fuel injection valves), the movement of the valve body of each fuel injection valve changes due to a fixed difference, such as a spring characteristic and a solenoid characteristic of each fuel injection valve. This causes the valve opening and closing times of the fuel injection valves to vary, resulting in variations in the injection quantity.

[0005] For this reason, various techniques have been proposed for detecting an individual difference generated for each fuel injection valve. PTL 1, for example, discloses a technique for indirectly detecting an individual difference based on an electrical characteristic curve during a valve opening process (in particular, the point in time at which a valve body enters an open valve state) of a fuel injection valve. Furthermore, a technique for detecting a valve closing process of a fuel injection valve based on an electrical characteristic curve is known, and a technique for correcting a change in the injection quantity by correcting a drive current and an injection pulse using information about a fixed difference is also known.

[0006] It is now necessary to detect a fixed difference in a state where factors that alter the electrical characteristics due to faults other than the fixed difference are excluded, in order to detect the fixed difference of the fuel injection valve from the electrical characteristic curve with high accuracy. Therefore, PTL 2 discloses a technique for sequentially monitoring a change in the state of an internal combustion engine, such as a change in fuel pressure, engine speed, the length of a control pulse, and the interval between a control pulse and the control pulse of the next injection, at the time of detecting a fixed difference of a fuel injection valve, and for stopping or preventing the detection of the fixed difference if it is determined that the valve behavior of any fuel injection valve is changing due to these disturbances. List of patent literature PTL 1: JP 2014 - 152 697 A PTL 2: WO 2017 / 006 814 A

[0007] US 2016 / 0 076 498 A1 describes an electromagnetic valve control and a device for controlling an internal combustion engine using valve control. WO 2013 / 191 267 A1 discloses a control device that detects individual differences in the respective amount of gasoline injected into each cylinder and, to compensate, adjusts the width of the injection pulse and the shape of the current supplied to the solenoid. US 2018 / 0 195 450 A1 relates to a fuel injector control device for a cylinder direct-injection internal combustion engine. US 2015 / 0 377 176 A1 describes a fuel injection device that can reliably detect the operating point of a valve body, i.e., the valve opening point, with high accuracy. Summary of the invention TECHNICAL PROBLEM

[0008] The technique described in PTL 2, however, only specifies whether the fixed differential measurement should be dependent on the state of the internal combustion engine. As described above, the fixed differential of the fuel injection valve allows for indirect detection of the valve opening or closing based on the electrical characteristic curve. Thus, a fault in an input circuit of an electrical signal used to detect the electrical characteristic curve, or in a drive circuit controlling a filter function, a fuel injection valve body, or the fuel injection valve itself, will disrupt the fixed differential measurement. In other words, if the fixed differential measurement is performed in a state where the fault described above occurs, the information about the fixed differential will not provide information about the valve opening or closing.Therefore, if the injection quantity is corrected based on these pieces of information, there will be a large deviation between the target injection quantity and the actual injection quantity, which can lead to a deterioration in fuel consumption and exhaust performance, as well as an unintended change in the torque of the internal combustion engine.

[0009] The present invention was made in view of the above circumstances, and one object of it is to provide a technique that is capable of adequately detecting an anomaly in the voltage information which is a basis for correcting a fuel injection quantity. Solution to the problem

[0010] To achieve the above task, a fuel injection control device, according to one aspect, is a fuel injection control device comprising: a first voltage supply unit that provides a first voltage; a second voltage supply unit that provides a second voltage that is higher than the first voltage; and a fuel injection control unit that controls the second voltage supply unit to supply the second voltage to a coil to open a fuel injection valve having the coil, and that controls the first voltage supply unit to supply the first voltage to the coil to maintain a valve opening state of the fuel injection valve, and comprising: a voltage measuring unit that measures and outputs voltage information based on an upstream voltage of the coil of the fuel injection valve and a downstream voltage of the coil;a correction unit that corrects the fuel injection quantity of the fuel injection valve based on the voltage information output by the voltage measuring unit; and an anomaly detection unit that detects whether an output of the voltage measuring unit is abnormal based on the voltage information output by the voltage measuring unit. Advantageous effects of the invention

[0011] According to the present invention, it is possible to detect an anomaly in the voltage information, which is a basis for correcting a fuel injection quantity, in a suitable manner. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] Fig. Figure 1 is an overall configuration diagram of an internal combustion engine system according to one embodiment. [ Fig. 2] Fig. Figure 2 is a configuration diagram of a fuel injection control device and associated parts according to the embodiment. [ Fig. 3] Fig. Figure 3 is a diagram showing the drive units for fuel injection and a peripheral circuit according to the embodiment. [ Fig. 4] Fig. Figure 4 is a configuration diagram of a fuel injection valve according to the embodiment. [ Fig. 5] Fig. Figure 5 is a view describing a method for actuating a fuel injection valve according to the embodiment. [ Fig. 6] Fig. Figure 6 is a configuration diagram of a drive power input unit and peripheral parts according to the embodiment. [ Fig. 7] Fig. Figure 7 is a view describing a method for detecting an inflection point of a drive voltage according to the embodiment. [ Fig. 8] Fig. Figure 8 is a view describing a drive voltage according to the embodiment. [ Fig. 9] Fig. Figure 9 is a view describing a fault detection method for a downstream low-voltage fault according to the embodiment. [ Fig. 10] Fig. Figure 10 is a view describing a fault detection method for a downstream high-voltage fault according to the embodiment. [ Fig. 11] Fig. Figure 11 is a view describing a fault detection method for an upstream high-voltage fault according to the embodiment. [ Fig. 12] Fig. Figure 12 is a view describing a fault detection method for an upstream low-voltage fault according to the embodiment. [ Fig. 13] Fig. Figure 13 is a view describing a fault detection procedure during a FastFall period according to the embodiment. [ Fig. 14] Fig. Figure 14 is a view describing a fault detection method during the excitation of a holding current according to the embodiment. [ Fig. 15] Fig. Figure 15 is a view describing a voltage change caused by a leakage current according to the embodiment. [ Fig. 16] Fig. Figure 16 is a view describing a fault detection method for a downstream fault using a leakage current according to the embodiment. [ Fig. 17] Fig. Figure 17 is a view describing a fault detection method for an upstream fault using a leakage current according to the embodiment. Description of embodiments

[0012] Several embodiments are described with reference to the drawings. Furthermore, the embodiments described below do not limit the invention according to the claims, and all elements and combinations thereof described in the embodiments are not necessarily required for the solution of the invention.

[0013] Fig. Figure 1 is an overall configuration diagram of an internal combustion engine system according to one embodiment. Incidentally, in Fig. 1 only one cylinder of several cylinders of engine 101 is shown.

[0014] An internal combustion engine system 100 comprises an engine 101, which is an example of an internal combustion engine, and an engine control unit (ECU) 109. The engine 101 is, for example, an inline four-cylinder gasoline engine.

[0015] Air drawn into the engine 101 through an intake opening (not shown) flows via an air flow meter (AFM) 120 and a throttle valve 119 to a collector 115. The air flow meter 120 measures the amount of air drawn in (intake air volume). The air flowing into the collector 115 is directed via an intake pipe 110 and an intake valve 103 connected to each cylinder of the engine 101 into a combustion chamber 121.

[0016] Meanwhile, fuel stored in a fuel tank 123 is drawn in by a low-pressure fuel pump 124 and fed to a high-pressure fuel pump 125 located in the engine 101. In the high-pressure fuel pump 125, an internal piston is moved up and down by a drive force transmitted by an exhaust camshaft (not shown) having an exhaust cam 128, thereby increasing the pressure of the supplied fuel. Based on a control command from a fuel injection control device 127 of the ECU 109, the high-pressure fuel pump 125 controls a solenoid of an on / off valve of an intake port (not shown) so that the fuel to be discharged has the desired pressure. The fuel delivered by the high-pressure fuel pump 125 is supplied to a fuel injection valve 105 via a high-pressure fuel line 129.The fuel injection valve 105 injects the fuel into the combustion chamber 121 based on a command from the fuel injection control device 127 of the ECU 109.

[0017] The engine 101 is equipped with a fuel pressure sensor 126, which measures the pressure (fuel pressure) of the fuel in the high-pressure fuel line 129. The ECU 109 performs feedback control based on a measurement result (sensor value) from the fuel pressure sensor 126, i.e., it transmits a control command to the high-pressure fuel pump 125 so that the fuel pressure in the high-pressure fuel line 129 reaches the desired pressure.

[0018] The engine 101 further comprises, for each combustion chamber 121, a spark plug 106 configured to generate a spark in the combustion chamber 121, and an ignition coil 107 that supplies the spark plug 106 with electrical energy. The ECU 109 controls the excitation of the ignition coil 107 so that the spark is emitted by the spark plug 106 at a desired time.

[0019] An air-fuel mixture of air and fuel is introduced into the combustion chamber 121 and ignited by the spark from the spark plug 106. A piston 102 is forced downwards by the pressure generated during the combustion of the air-fuel mixture. The exhaust gas produced during combustion is routed via an exhaust valve 104 and an exhaust pipe 111 to a three-way catalytic converter 112. The three-way catalytic converter 112 performs exhaust gas purification to clean the exhaust gas. The exhaust gas, cleaned by the three-way catalytic converter 112, flows downstream and is finally released into the atmosphere.

[0020] The internal combustion engine system 100 comprises: a water temperature sensor 108, which measures the temperature of coolant used to cool the engine 101; a crankshaft angle sensor 116, which measures the angle of a crankshaft (not shown) of the engine 101; the AFM 120, which measures the amount of intake air; an oxygen sensor 113, which detects the oxygen concentration in an exhaust gas in the exhaust pipe 111; an accelerator pedal opening degree sensor 122, which detects the degree of opening (accelerator pedal opening degree) of an accelerator pedal operated by a driver; and the fuel pressure sensor 126, which measures the pressure of the fuel in the high-pressure fuel line 129.

[0021] The ECU 109 receives signals with measurement results from sensors such as the water temperature sensor 108, the crank angle sensor 116, the AFM 120, the oxygen sensor 113, the accelerator pedal opening degree sensor 122 and the fuel pressure sensor 126.

[0022] The ECU 109 performs various processes based on different input signals. For example, the ECU 109 performs a process to calculate the required torque of the engine 101 based on the signal input from the accelerator pedal opening sensor 122, and performs a process to determine whether the engine 101 is idling, and so on. Furthermore, the ECU 109 performs a process to calculate the engine speed (engine RPM) based on the signal input from the crankshaft position sensor 116. Additionally, the ECU 109 performs a process to determine whether the three-way catalytic converter 112 is in a warm-up state, based on a coolant temperature input from the water temperature sensor 108, the time elapsed since the engine was started, and so on.

[0023] Furthermore, the ECU 109 calculates the required intake air volume for the engine 101 based on the calculated required torque and the like, and outputs a signal to the throttle valve 119 to adjust the opening degree corresponding to the calculated intake air volume. The fuel injection control unit 127 is integrated into the ECU 109. The fuel injection control unit 127 of the ECU 109 calculates a fuel quantity corresponding to the intake air volume (required injection quantity), outputs a fuel injection signal to the fuel injection valve 105, and also outputs an ignition signal to the ignition coil 107.

[0024] The fuel injection control device 127 and parts associated with the fuel injection control device 127 are described in detail below.

[0025] Fig. Figure 2 is a configuration diagram of a fuel injection control device and associated parts according to one embodiment.

[0026] The fuel injection control device 127 of the ECU 109 comprises a control unit 200, an integrated drive circuit (IC) 208, a high-voltage generation unit 206, fuel injection drive units 207a and 207b, and a drive voltage input unit 211. A battery voltage 209 supplied by a battery (not shown) is routed to the high-voltage generation unit 206 and the fuel injection drive unit 207a via a fuse 204 and a relay 205.

[0027] The control unit 200 includes, for example, a microcomputer having a central processing unit (CPU), a memory (storage device), an I / O port, and the like. The control unit 200 includes a pulse signal calculation unit 201, a drive shaft shape command unit 202, an engine state detection unit 203, a fuel injection quantity correction unit 213, which is an example of a correction unit, and a voltage input function anomaly detection unit 212, which is an example of an anomaly detection unit.

[0028] The engine condition detection unit 203 collects various types of information, such as engine speed, intake air quantity, coolant temperature, fuel pressure and engine fault condition, and delivers the information to the pulse signal calculation unit 201 and the drive shaft shape command unit 202.

[0029] The pulse signal calculation unit 201 determines a width (excitation time Ti) of an injection pulse signal that defines a fuel injection period through the fuel injection valve 105, based on various types of information from the engine state detection unit 203 and information from the fuel injection quantity correction unit 213, and outputs the width to the control IC 208.

[0030] The control waveform command unit 202 calculates a command value of a control current to be supplied to open the fuel injection valve 105 or to maintain the valve opening, based on the different types of information from the engine state detection unit 203 and information from the fuel injection quantity correction unit 213, and outputs the command value as a command to the control IC 208.

[0031] The fuel injection quantity correction unit 213 detects an individual difference of the fuel injection valve 105 based on voltage difference information, to be described later, which is output by the drive voltage input unit 211, calculates information that specifies a correction quantity of a fuel injection quantity according to the fixed difference, and informs the pulse signal calculation unit 201 and the drive shaft shape command unit 202 about the information.

[0032] The voltage input function anomaly detection unit 212 determines, based on the voltage difference information output by the drive voltage input unit 211, whether the voltage difference information output by the drive voltage input unit 211 is anomalous. Details of a procedure for determining anomalies, which is carried out by the voltage input function anomaly detection unit 212, are described later.

[0033] The drive voltage input unit 211 outputs the voltage difference information (an example of voltage information) based on a difference between a voltage (upstream voltage) on the upstream side of a solenoid 405 of the fuel injection valve 105 and a voltage (downstream voltage) on the downstream side. In the present embodiment, the drive voltage input unit 211 outputs, for example, a voltage obtained by dividing a differential voltage between the upstream voltage and the downstream voltage of the solenoid 405 of the fuel injection valve 105 in a predetermined ratio. A specific configuration of the drive voltage input unit 211 is described later.

[0034] The control IC 208 selects a control period of the fuel injection valve 105 (excitation time of the fuel injection valve 105), selects a drive voltage (selects either a high voltage 210 or the battery voltage 209) and determines a setpoint of a control current based on a command from the pulse signal calculation unit 201 and a command from the control waveform command unit 202 and controls the high voltage generation unit 206 and the fuel injection control units 207a and 207b according to the determination, thereby controlling the drive current to be supplied to the fuel injection valve 105.

[0035] The high-voltage generating unit 206 generates a high-power supply voltage (high voltage 210: second voltage) from the battery voltage 209. This high-power supply voltage is applied to the fuel injection valve 105 at the time of opening of a valve body provided in the solenoid-type electromagnetic fuel injection valve 105, and is supplied to the fuel injection drive unit 207a. Specifically, the high-voltage generating unit 206 increases the battery voltage 209 supplied by the battery to achieve a desired target high voltage based on the command from the drive IC 208, in order to generate the high voltage 210 higher than the battery voltage 209.As a result, voltages from two systems, namely the high voltage 210 for the purpose of ensuring a valve opening force of the valve body and the battery voltage 209 (low voltage: first voltage) for keeping the valve open so that the valve body is not closed after the valve opening, are provided as the power supply that supplies the voltage to the fuel injection valve 105, and the high voltage and the low voltage can be supplied.

[0036] The fuel injection drive unit 207a is electrically connected to the upstream side of the solenoid 405, which is an example of a coil of the fuel injection valve 105. The control of the voltage supply to the fuel injection valve 105 and the selection of the voltage to be supplied (selection of the high voltage 210 generated by the high voltage generation unit 206 or the battery voltage 209) are carried out based on the control by the drive IC 208. The fuel injection drive unit 207a corresponds to a first voltage supply unit and a second voltage supply unit.

[0037] The drive unit 207b for the fuel injection is electrically connected to the downstream side of the solenoid 405 of the fuel injection valve 105 and switches, based on the control by the drive IC 208, whether the fuel injection valve 105 should be grounded or not.

[0038] The following describes the configurations and operation of the 207a and 207b drive units for fuel injection.

[0039] Fig. Figure 3 is a diagram showing the drive units for fuel injection and a peripheral circuit according to the embodiment.

[0040] The fuel injection drive unit 207a comprises a diode 301, a switching element 303, a diode 302, and a switching element 304. One end of the diode 301 is electrically connected to the high-voltage generating unit 206, and the other end is electrically connected to the switching element 303. The diode 301 prevents current from flowing back to the high-voltage generating unit 206. The switching element 303 is, for example, a transistor whose collector is electrically connected to the diode 301, whose base is electrically connected to the driver IC 208, and whose emitter is electrically connected to the fuel injection valve 105 (specifically, the solenoid 405). The switching element 303 controls the supply of current from the diode 301 to the fuel injection valve 105 based on a signal input at its base by the driver IC 208.The current required to open the fuel injection valve 105 is supplied to the electric quantity injection valve 105 via such a path.

[0041] Diode 302 is electrically connected at one end to the battery voltage 209 and at the other end to the switching element 304. Diode 302 prevents reverse current flow to the battery voltage 209. Switching element 304 is, for example, a transistor whose collector is electrically connected to diode 302, whose base is electrically connected to the driver IC 208, and whose emitter is electrically connected to the fuel injection valve 105 (specifically, the solenoid 405). Switching element 304 controls the supply of current from diode 302 to the fuel injection valve 105 based on a signal input at its base by the driver IC 208.

[0042] Based on the output and command from the control unit 200, the fuel injection drive unit 207a applies the high voltage 210 generated by the high voltage generation unit 206 to the fuel injection valve 105 when a signal to switch on the switching element 303 is input from the drive IC 208, and applies the battery voltage 209 to the fuel injection valve 105 when a signal to switch on the switching element 304 is input from the drive IC 208.

[0043] The fuel injection drive unit 207b comprises a switching element 305 and a shunt resistor 306. The switching element 305 is, for example, a transistor whose collector is electrically connected to the fuel injection valve 105, whose base is electrically connected to the driver IC 208, and whose emitter is electrically connected to the shunt resistor 306. The switching element 305 controls the supply of current from the fuel injection valve 105 to the shunt resistor 306 based on a signal input at its base by the driver IC 208. The shunt resistor 306 is electrically connected to the switching element 305 at one end and grounded at the other. The shunt resistor 306 detects the current flowing between the resistors and outputs it to the drive IC 208.

[0044] Based on the command from the control unit 200, the fuel injection control unit 207b can apply a voltage supplied to the fuel injection valve 105 by the fuel injection control unit 207a when a signal to switch on the switching element 305 is input from the control IC 208, and can perform a desired current control of the fuel injection valve 105, which will be described later, by detecting the current consumed by the fuel injection valve 105 from the current flowing between the resistors of the shunt resistor 306. Incidentally, a method for actuating the fuel injection valve 105 is not limited to the example above.For example, in a case where fuel pressure is relatively low, in a case where the high voltage generating unit 206 has failed, or in a similar case, the battery voltage 209 can be provided instead of the high voltage 210 at the time the fuel injection valve 105 opens.

[0045] The following section describes in detail the structure and function of the fuel injection valve 105.

[0046] Fig. Figure 4 is a configuration diagram of the fuel injection valve according to the embodiment.

[0047] The fuel injection valve 105 comprises: a cylindrical housing 402 with a valve seat 406 in which an opening (injection hole 407) is formed for injecting fuel; a valve body 403 which performs a reciprocating (vertical) movement along a central axis of the housing 402; a movable core 401 which is shaped to surround a circumference of the valve body 403; a fixed core 404 which is fixed inside the housing 402; and the solenoid 405 as an example of a coil which is wound around the fixed core 404 and which generates a force to attract the movable core 401.

[0048] An actuating spring 408, which moves the valve body 403 towards the valve seat 406 (in Fig. The spring 409, which is biased downwards (4), is provided in an upper part of the valve body 403. Furthermore, a zero spring 409 is provided between the movable core 401 and the housing 402, which biases the movable core 401 upwards.

[0049] In the fuel injection valve 105, when the interior of the housing 402 is filled with fuel and a current flows through the solenoid 405, the movable core 401 is attracted to the solenoid 405 by an attractive force of a magnetic flux through the solenoid 405, and a lower end of the valve body 403 is separated from the valve seat 406, thereby injecting the internal fuel from the injection port 407 of the housing 402.

[0050] Then, when the current supplied to the solenoid 405 becomes small and the attractive force weakens, the valve body 403 returns to a starting position (i.e., a position in which the valve body 403 is in contact with the valve seat 406) in which the zero spring 409 and the adjusting spring 408 are balanced, thus ending the fuel injection.

[0051] Next, an example of changes to an injection pulse, drive voltage and control current, as well as an adjustment amount (valve adjustment) of the valve body 403, is described when the fuel injection valve 105 is actuated to inject fuel.

[0052] Fig. Figure 5 is a view describing a method for actuating a fuel injection valve according to the embodiment.

[0053] An injection pulse output by the pulse signal calculation unit 201 is in an off state, i.e., a period is formed between times T0 and T1 in which fuel injection control by the fuel injection valve 105 is not carried out. The fuel injection drive units 207a and 207b are in the off state, so no drive current is supplied to the fuel injection valve 105. Therefore, the lower end of the valve body 403 is in a position in contact with the valve seat 406 (the valve adjustment is zero) due to a preload force of the adjusting spring 408 of the fuel injection valve 105, which biases the valve body 403 in the direction towards the valve seat 406 (valve closing direction). Thus, the injection orifice 407 is closed, so no fuel is injected.

[0054] Subsequently, at time T1, the injection pulse is switched on, the fuel injection drive unit (Hi) 207a and the fuel injection drive unit (Lo) 207b are switched on, and a section between the high-voltage generating unit 206 and ground becomes conductive via the solenoid 405 of the fuel injection valve 105. As a result, a drive voltage of the high voltage 210 is applied to the solenoid 405, and the drive current begins to flow through the solenoid 405. This generates a magnetic flux between the fixed core 404 and the moving core 401, so that a magnetic attraction force acts on the moving core 401.

[0055] When the drive current supplied to the solenoid 405 increases and the magnetic attraction force acting on the movable core 401 exceeds the preload force of the zero spring 409, the movable core 401 is pulled towards the fixed core 404 and begins to move (time points T1 to T2).

[0056] Then, when an upper surface of the movable core 401 moves a length that comes into contact with the upper part of the valve body 403, the movable core 401 and the valve body 403 begin to move together (time T2). This separates and opens the valve body 403 from the valve seat 406, and the injection of fuel from the injection port 407 is initiated.

[0057] The movable core 401 and the valve body 403 then move together until the movable core 401 comes into contact with the fixed core 404. If the movable core 401 and the fixed core 402 collide violently at this point, the movable core 401 rebounds and moves downwards due to the collision with the fixed core 402, thus disrupting the flow of fuel injected from the injection port 407.Therefore, in the present embodiment, the motion impulse of the movable core 401 and the valve body 403 is reduced (hereinafter, a period in which such control is carried out is referred to as the FastFall period) by switching off the fuel injection drive units 207a and 207b and reducing the drive voltage applied to the solenoid 405 in order to reduce the drive current at a time (time T3) before the movable core 401 comes into contact with the fixed core 404, for example, when the drive current reaches a peak current Ip1.

[0058] Subsequently, a control (PMW control) is carried out to intermittently switch on the fuel injection drive unit (Hi) 207a in a state in which the fuel injection drive unit (Lo) 207b is held in the switched-on state, in order to intermittently adjust the drive voltage applied to the solenoid 405 to the battery voltage 209 in order to provide only the magnetic attraction force sufficient to attract the movable core 401 to the fixed core 404 from a time T4 until a time T6, when the injection pulse falls, and the control is carried out such that the drive current flowing through the solenoid 405 falls within a predetermined range.

[0059] Since the injection pulse is switched off at time T6, all drive units 207a and 207b for fuel injection are deactivated. As a result, the drive voltage applied to the solenoid 405 decreases, and the drive current flowing through the solenoid 405 also decreases after time T6. Consequently, the magnetic flux generated between the fixed core 404 and the movable core 401 gradually disappears, and the magnetic attraction acting on the movable core 401 diminishes. This causes the valve body 403 to be pushed back in the valve closing direction of the valve seat 406 by the preload force of the actuating spring 408 and a contact force from fuel pressure with a predetermined time delay.When the valve body 403 is then returned to its original position, as shown at time T7, the lower end of the valve body 403 abuts the valve seat 406 to close, and the injection of fuel from the injection port 407 is stopped.

[0060] Furthermore, any residual magnetic force in the fuel injection valve 105 can be quickly eliminated from time T6 when the injection pulse is switched off, and the high voltage 210 can be supplied to the solenoid 405 in the opposite direction to that used when driving the fuel injection valve 105, so that the valve body 403 is closed prematurely.

[0061] The configurations of the drive power input unit 211 and the peripheral sections are described below.

[0062] Fig. Figure 6 is a configuration diagram of a drive power input unit and peripheral sections according to the embodiment.

[0063] The drive voltage input unit 211 comprises a voltage divider circuit 601, 602, a differential circuit 605 and an AD converter 606.

[0064] The voltage divider circuit 601 is connected via an electrical wire 215 to the upstream side (positive terminal) of the solenoid 405 of the fuel injection valve 105, divides the upstream voltage, and outputs it. In the present embodiment, the voltage divider circuit 601 includes voltage divider resistors R1 and R2. In the present embodiment, a capacitor C1 is connected to the voltage divider circuit 601 to form a low-pass filter 602. The low-pass filter 602 can smooth and output divided voltages of an input voltage.

[0065] The voltage divider circuit 603 is connected via an electrical wire 214 to the downstream side (negative terminal) of the solenoid 405 of the fuel injection valve 105, divides the downstream voltage, and outputs it. In the present embodiment, the voltage divider circuit 603 includes voltage divider resistors R3 and R4. The ratio of the resistances of voltage divider resistors R1 and R2 is the same as the ratio of the resistances of voltage divider resistors R3 and R4 in the present embodiment. In the present embodiment, a capacitor C2 is connected to the voltage divider circuit 603 to form a low-pass filter 604. The low-pass filter 604 can smooth and output the divided voltages of an input voltage.

[0066] Incidentally, the voltage divider circuits 601 and 603 are circuits configured to keep the upstream and downstream voltages of the solenoid 405 within a voltage range that can be processed by a subsequent circuit or similar device, and the voltage divider circuits 601 and 603 are not strictly necessary as long as the processing can be carried out without voltage division.

[0067] The differential circuit 605 outputs a voltage (differential voltage) that corresponds to the difference between the divided voltages output by the voltage divider circuit 601 and the voltage divider circuit 603. Here, the differential voltage output by the differential circuit 605 is in a predefined ratio (in this case, a ratio corresponding to the voltage division ratio of the voltage divider circuits 601 and 603) to a differential voltage between the upstream and downstream voltages of the solenoid 405 and can be described as voltage difference information based on the voltage difference between the upstream and downstream voltages.

[0068] The AD converter 606 performs a digital conversion of the differential voltage output by the differential circuit 605 and outputs the converted differential voltage.

[0069] Incidentally, the configuration of the drive voltage input unit 211 is not based on the configuration of Fig. 6. For example, the A / D converter can perform a digital conversion of the voltages divided by the voltage divider circuits 601 and 603, apply a low-pass filter to this digitally converted data by software processing, and calculate a differential voltage from the two obtained voltages. Furthermore, the differential voltage can be the difference between the downstream voltage of the fuel injection valve 105 and an installation voltage.

[0070] Next, the processing of the fuel injection quantity correction unit 213 will be described.

[0071] Fig. Figure 7 is a view describing a method for detecting an inflection point of a drive voltage according to the embodiment. Fig. Figure 7 shows a diagram illustrating the change of the drive voltage over time, and a diagram illustrating the change of a second-order difference value of the drive voltage over time. The drive voltage in Fig. Incidentally, 7 corresponds to the drive voltage after time T6. Fig. 5.

[0072] When the valve body 403 of the fuel injection valve 105 is closed, the valve body 403 abuts the valve seat 406. When the valve body 403 collides with the valve seat 406 in this way, the zero spring 409 transitions from extension to compression, the direction of movement of the movable core 401 is reversed, the acceleration changes, and the inductance of the solenoid 405 changes. When the valve body 403 is closed, the drive current flowing through the solenoid 405 is interrupted, and an electromotive force is exerted on the solenoid 405. As the drive current converges, the counter-electromotive force also gradually decreases, thus creating a turning point 501 in the drive voltage, as shown in Fig. 7 is shown, since the inductance changes when the counter-electromotive force decreases.

[0073] In this way, the inflection point of the drive voltage, which occurs when the valve closes, indicates a valve closing time of the fuel injection valve 105. For this reason, a time 502 from time T6, at which the drive pulse is switched off, until the inflection point 501 can be set as the valve closing completion time.

[0074] The inflection point 501 of the drive voltage appears as an extreme value (maximum or minimum value) in a second-order differential obtained by differentiating the time-series data of the drive voltage applied to the solenoid 405. Therefore, the inflection point 501 can be appropriately identified by detecting an extreme value 701 in the time-series data of the drive voltage. Thus, the fuel injection correction unit 213 determines the extreme value 701 using the second-order differential of the time-series data of the drive voltage to identify the inflection point 501 and identifies the valve closing time 502.

[0075] When second-order differentiation is applied to the drive voltage time series data from time T6, when the injection pulse is switched off, the time at which a voltage is switched (e.g., the time at which the high voltage 210 is switched to the battery voltage 209, or the time at which the electromotive force is applied after the drive voltage is switched off) is likely to appear as an extreme value, and there is a case where it is difficult to precisely identify an inflection point generated by a change in the acceleration of the moving core 401. Therefore, the time series data to be subjected to second-order differentiation are preferably drive voltage time series data after a predetermined time has elapsed since the injection pulse was switched off (in other words, since the drive voltage was switched off). The predetermined time can be, for example,This will be a time until the voltage is no longer switched off, as the injection pulse has been switched off.

[0076] Once the detection (identification) of the valve closing time is complete, the fuel injection correction unit 213 compares the detected valve closing time with a valve closing time (reference valve closing time) that serves as a pre-stored reference and notifies the pulse signal calculation unit 201 and the drive shaft shape command unit 202 of an instruction to correct the drive current to obtain an appropriate injection quantity (which corresponds to an instruction to correct a fuel injection quantity). For example, if the detected valve closing time is longer than the reference valve closing time, the fuel injection correction unit 213 issues an instruction to reduce a peak current.If the peak current is reduced in this way, the valve body opening process can be delayed and the fuel injection quantity reduced to approximate a reference characteristic curve of a fuel injection valve. Conversely, if the determined valve closing time is shorter than the reference valve closing time, the fuel correction unit 213 instructs a reduction of the peak current. If the peak current is increased in this way, the valve body opening process can be accelerated and the fuel injection quantity increased to approximate a reference characteristic curve of a fuel injection valve.

[0077] The injection quantity correction described above is performed based on the valve closing time, which is determined from the drive voltage (differential voltage) output by the drive voltage input unit 211. If the drive voltage output by the drive voltage input unit 211 has an abnormal value, it is difficult to issue the correction appropriately, and therefore it is difficult to inject an appropriate amount of fuel when the fuel injection is performed according to the correction instruction. Therefore, the fuel injection quantity correction unit 213 issues the instruction to correct the fuel injection quantity when the voltage input function anomaly detection unit 212 determines that the output of the drive voltage input unit 211 is not abnormal, i.e.,does not detect that an error where the output is abnormal has occurred, and stops the instruction to correct the fuel injection quantity in order to terminate the fuel injection quantity correction when it is detected that the error where the output of the drive voltage input unit 211 is abnormal has occurred.

[0078] In this way it is possible to determine whether the injection quantity needs to be corrected based on a determination result of the voltage input function anomaly detection unit 212, it is possible to adequately prevent an unintentional change in the injection quantity, and it is possible to prevent the deterioration of fuel consumption performance and exhaust performance.

[0079] Next, a processing operation of the voltage input function anomaly detection unit 212 is described.

[0080] The voltage input function anomaly detection unit 212 determines whether the voltage difference information output by the drive voltage input unit 211 is normal.

[0081] If an anomaly occurs in the voltage difference information output by the drive voltage input unit 212, it is difficult to accurately detect the inflection point generated by the valve body operation of the fuel injection valve 105, i.e., the point in time at which the extreme value is generated from the anomalous voltage difference information, even though the fuel injection valve 105 is operating normally. As a result, the valve closing time determined by the fuel injection quantity correction unit 213 deviates from the actual valve body operation, and it is difficult to accurately correct the fuel injection quantity. This can lead to a deterioration in fuel consumption and exhaust performance, as well as an unintended change in torque.

[0082] For example, if the voltage divider resistor R4, which is connected to the downstream side of the fuel injection valve 105, or the capacitor C2, which is used for the low-pass filter, is short-circuited and connected to a ground voltage, if the electrical line 214, to which the voltage is applied, is interrupted, or similar, a fault (called a downstream low-voltage fault) will occur in which the measuring voltage on the downstream side will assume a low value.

[0083] Furthermore, if a short circuit occurs with an adjacent signal line (not shown), a short circuit with a signal line (not shown) such as a power supply system, a short circuit of the voltage divider R3 or similar, a fault (a downstream high-voltage fault) occurs in which the measurement voltage on the downstream side assumes a high value.

[0084] The same applies to a voltage on the upstream side of the solenoid 405. If the voltage division resistor R1 or the capacitor C1 used for the low-pass filter is short-circuited and connected to ground, if the electrical line 215 to which the voltage is applied is interrupted, or similar, a fault (upstream low-voltage fault) occurs in which the measuring voltage on the upstream side assumes a low value.

[0085] If a short circuit occurs with an adjacent signal line (not shown), a short circuit with a signal line (not shown) such as a power supply system, a short circuit of the voltage divider resistor R1 or similar, a fault (high-voltage fault) occurs in which the measurement voltage on the upstream side assumes a high value.

[0086] With regard to the drive voltage (differential voltage), a correspondence relationship between the measuring voltage on the upstream side of the solenoid 405 and the measuring voltage on the downstream side at the time of the drive voltage in a normal state is described next.

[0087] Fig. Figure 8 is a view describing a drive voltage according to the embodiment. The in Fig. The drive voltage shown in section 8 corresponds to the one in Fig. 5 shown drive voltage.

[0088] The injection pulse is switched on at time T1, the fuel injection drive unit (Hi) 207a and the fuel injection drive unit (Lo) 207b are switched on, and a section between the high-voltage generating unit 206 and ground becomes conductive via the solenoid 405 of the fuel injection valve 105. As a result, a drive voltage of the high voltage 210 is applied to the solenoid 405, and the drive current begins to flow through the solenoid 405.

[0089] At this time, a high voltage is present on the upstream side of the solenoid 405 of the fuel injection valve 105, while a ground voltage is present on the downstream side.

[0090] At time T3, when the drive current reaches the peak current Ip1, the drive units 207a and 207b for fuel injection are switched off, and the high voltage 210 is supplied in the reverse direction. As a result, the drive voltage applied to the solenoid 405 decreases from time T3 to time T4. At this time, a ground voltage is present on the upstream side of the solenoid 405 of the fuel injection valve 105, while the high voltage gradually decreases on the downstream side.

[0091] During a period from time T4 to time T6, when an injection pulse occurs, the fuel injection drive unit (Hi) 207a is intermittently switched on, while the fuel injection drive unit (Lo) 207b is held in the switched-on state. This allows the drive voltage applied to the solenoid 405 to be intermittently adjusted to the battery voltage 209. The control is performed such that the drive current flowing through the solenoid 405 falls within a predetermined range. At this time, an arbitrary voltage between the battery voltage and ground voltage is repeatedly present on the upstream side of the solenoid 405 of the fuel injection valve 105, and ground voltage is present on the downstream side.

[0092] When the injection pulse is switched off at time T6, all fuel injection drive units 207a and 207b are switched off, the high voltage 210 is supplied in the reverse direction as at the time of actuation of the fuel injection valve 105, and the drive voltage applied to the solenoid 405 decreases.

[0093] As described above, the voltage behavior on the upstream and downstream sides changes depending on the control state of the injection drive units 207a and 207b. For example, if a low-voltage fault occurs on the downstream side, the measured voltage on the downstream side becomes low, making it difficult to distinguish between normality and fault conditions between times T1 and T3 and between times T4 and T6. Similarly, in the case of a high-voltage fault on the upstream side, it is difficult to differentiate between times T3 and T4 and after time T6.

[0094] Therefore, the voltage input function anomaly detection unit 212 of the present embodiment performs a fault determination according to the drive states of the fuel injection drive units 207a and 207b with regard to a fault that can be detected in such states.

[0095] Next, a fault detection method using the voltage input function abnormality detection unit 212 is described. In this example, the differential voltage (drive voltage) is defined as a differential voltage based on a value obtained by subtracting an upstream voltage from a downstream voltage of the solenoid 405 of the fuel injection valve 105. However, a fault can also be detected using a differential voltage based on a value obtained by subtracting a downstream voltage from an upstream voltage of the fuel injection valve 105.

[0096] First, a method for determining a downstream low-voltage fault after switching off an injection pulse is described.

[0097] Fig. Figure 9 is a view describing a fault detection method for a downstream low-voltage fault according to the embodiment.

[0098] As described above, when the injection pulse is switched off at time T6, the drive current flowing through solenoid 405 is interrupted, the high voltage 210 is applied in the reverse direction compared to that at the time of drive, and then the drive voltage gradually decreases. This means that the upstream voltage of solenoid 405 of the fuel injection valve 105 becomes a low voltage, the downstream voltage becomes a high voltage, and then the downstream voltage gradually decreases. Finally, there is no potential difference between the upstream and downstream voltages.

[0099] When the downstream low voltage fault occurs, a measurement voltage measured by the drive voltage input unit 211 on the downstream side (downstream measurement voltage) becomes a low voltage, so that a differential voltage between the downstream measurement voltage and an upstream measurement voltage is always a low voltage, as indicated by line 903. Therefore, the voltage input function anomaly detection unit 212 determines that a fault (anomaly: downstream low voltage fault) is present when a differential voltage value after the injection pulse is switched off is not equal to or greater than a threshold value (threshold 901 for determining the downstream low voltage fault), which is a value greater than a differential voltage value (voltage value indicated by line 903) when an anomaly occurs.Furthermore, the voltage input function anomaly detection unit 212 can determine that no fault is present if the differential voltage value after the injection pulse is switched off is equal to or greater than the threshold 901 for determining the downstream low voltage fault.

[0100] However, the differential voltage between the upstream and downstream voltages decreases, and it becomes difficult to distinguish between normality and faults as time elapses after the application of a reverse voltage as described above. Therefore, it is necessary to compare the differential voltage value with the threshold 901 for determining the downstream low-voltage fault to ascertain whether a fault exists at time 902 before the time at which the voltage, even under normal conditions after the injection pulse is switched off, falls below the threshold 901 for determining the downstream low-voltage fault of the input unit. Incidentally, the time 902 until the determination can be changed depending on the value to which the threshold 901 for determining the downstream low-voltage fault is set.Since the fuel pressure is lower when the injection pulse is switched off, the change in drive voltage is smoother, thus changing the time until determination according to the fuel pressure. That is, the time until determination can be shortened if the fuel pressure is higher.

[0101] Incidentally, the differential voltage value output by the drive voltage input unit 211 is the differential voltage value of the split voltage in the example shown in the present embodiment, and therefore the threshold value 901 for determining the downstream low-voltage fault must be a threshold value corresponding to a split differential voltage value. However, a specific value varies depending on whether the differential voltage value is the split differential voltage value or an undivided differential voltage value, but similar processing is performed, and therefore, for the sake of simplicity, the undivided differential voltage value is used in the following description of a fault determination procedure.Furthermore, the processing is described using the undivided differential voltage value or threshold, but the differential voltage value can be replaced by a divided differential voltage value and the threshold can be replaced by a divided threshold for a differential voltage when the divided differential voltage value is used.

[0102] Furthermore, the differential voltage value is compared with the threshold value 901 for determining the downstream low-voltage fault in order to perform the fault determination in the example above. For example, a differential voltage value under normal conditions (normal differential voltage value) can be measured in advance, and then it can be determined that a fault exists if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault exists if the difference is not equal to or greater than the certain value.

[0103] As with reference to Fig. As described in section 9, in the fuel injection control device 127, the voltage difference information (split voltage difference value) is based on the voltage difference obtained by subtracting the upstream voltage from the downstream voltage. The threshold is a lower threshold (threshold 901 for determining the downstream low-voltage fault), such that the voltage difference information is assumed to be equal to or greater than when an output of a voltage measuring unit (drive voltage input unit 211) is normal at a predetermined time (any time in time 902). The anomaly detection unit (voltage input function anomaly detection unit 212) determines that the output of the voltage measuring unit is anomalous when the voltage difference informationThe voltage output by the voltage measuring unit at the predetermined time must not be equal to or greater than the lower threshold value. In this way, the downstream low-voltage fault can be adequately detected.

[0104] Next, a method for detecting a downstream high-voltage fault after switching off an injection pulse is described.

[0105] Fig. Figure 10 is a view describing a fault detection method for a downstream high-voltage fault according to the embodiment.

[0106] When the downstream high-voltage fault occurs, a downstream measurement voltage becomes high and an upstream measurement voltage becomes low after the injection pulse is switched off, so that the differential voltage between the downstream and upstream measurement voltages always becomes high, as indicated by line 1002. Therefore, the voltage input function anomaly detection unit 212 determines that a fault (upstream high-voltage fault) is present when the differential voltage is not equal to or greater than a threshold (threshold 1001 for determining a downstream high-voltage fault), which is a value less than the differential voltage value (voltage value indicated by line 1002) when the anomaly occurs after the injection pulse is switched off.Furthermore, the voltage input function anomaly detection unit 212 can determine that no fault is present if the differential voltage after the injection pulse is switched off is equal to or greater than the threshold 1001 for determining the downstream high voltage fault.

[0107] Furthermore, the differential voltage value is compared with the threshold value of 1001 for determining the downstream high-voltage fault in order to perform the fault determination in the example above. For example, a differential voltage value under normal conditions (normal differential voltage value) can be measured in advance, and then it can be determined that a fault is present if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault is present if the difference is not equal to or greater than the certain value.

[0108] As with reference to Fig. As described in section 10, in the fuel injection control device 127, the voltage difference information (split voltage difference value) is based on the voltage difference obtained by subtracting the upstream voltage from the downstream voltage. The threshold is an upper threshold (threshold 1001 for determining the downstream high-voltage fault), such that the voltage difference information is assumed to be equal to or less than the value when the output of a voltage measuring unit (drive voltage input unit 211) is normal at a predetermined time. The anomaly detection unit (voltage input function anomaly detection unit 212) determines that the output of the voltage measuring unit is anomalous when the voltage difference information output by the voltage measuring unit at the predetermined time isis not equal to or less than the upper threshold. In this way, the downstream high-voltage fault can be adequately detected.

[0109] Next, a method for detecting an upstream high-voltage fault after switching off an injection pulse is described.

[0110] Fig. Figure 11 is a view describing a fault detection method for an upstream high-voltage fault according to the embodiment.

[0111] When the upstream high-voltage fault occurs, an upstream voltage becomes a high voltage after the injection pulse is switched off, and a differential voltage measured by the drive voltage input unit 211 becomes a low voltage, as indicated by line 1102. At this time, the differential voltage becomes a negative voltage if the maximum measurable voltage is greater than the high voltage 210 applied in the opposite direction on the downstream side.Therefore, the voltage input function anomaly detection unit 212 determines that a fault (upstream high-voltage fault) is present when the differential voltage does not equal to or exceed a threshold (threshold 1101 for determining an upstream high-voltage fault) which is a value higher than the differential voltage value (line 1102) when the fault occurs after the injection pulse has been switched off.

[0112] The threshold value 1101 for determining the upstream high-voltage fault can, incidentally, be the same value as the one in Fig. Figure 9 shows the threshold value 901 for determining the downstream low-voltage fault. If the threshold value 1101 for determining the upstream high-voltage fault is set relatively smaller than the threshold value 901 for determining the downstream low-voltage fault, it may be possible to distinguish between the upstream high-voltage fault and the downstream low-voltage fault.

[0113] Furthermore, the voltage input function anomaly detection unit 212 can determine that no fault is present if the differential voltage value after the injection pulse is switched off is equal to or greater than the threshold 1101 for determining the upstream high voltage fault.

[0114] Furthermore, the differential voltage value is compared with the threshold value 1101 for determining the upstream high-voltage fault in order to perform the fault determination in the example above. For example, a differential voltage value under normal conditions (normal differential voltage value) can be measured in advance, and then it can be determined that a fault is present if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault is present if the difference is not equal to or greater than the certain value.

[0115] Next, a method for determining an upstream low-voltage fault is described.

[0116] Fig. Figure 12 is a view describing a fault detection method for an upstream low-voltage fault according to the embodiment.

[0117] In the event of an upstream low-voltage fault, the upstream measurement voltage measured by the drive voltage input unit 211 becomes a low voltage. Simultaneously, an upstream voltage becomes a low voltage when the injection pulse is switched off. For this reason, when the injection pulse is switched off, it is difficult to distinguish whether the upstream low-voltage fault originates from a differential voltage. Therefore, the voltage input function anomaly detection unit 212 detects the upstream low-voltage fault when the injection pulse is switched on, at which point the upstream voltage becomes a high voltage.

[0118] Although the upstream voltage becomes a high voltage after the injection pulse is switched on, the upstream measurement voltage measured by the drive voltage input unit 211 becomes a low voltage when the upstream low voltage fault occurs, and the differential voltage between a downstream measurement voltage and the upstream measurement voltage is always zero, as indicated by a line 1202.Therefore, the voltage input function anomaly detection unit 212 determines that a fault (upstream low-voltage fault) is present if the differential voltage during a period 1203 from time T1, when the injection pulse is switched on, until time T3, is not equal to or less than a threshold value (threshold 1201 for determining the upstream low-voltage fault), which is a value lower than the differential voltage value (line 1202) when an anomaly occurs. The period 1203 can, incidentally, be calculated in advance by experiment or similar means.Alternatively, a fault (upstream low-voltage fault) can be determined if the differential voltage during a period in which the switching element 303 is switched on on the high-voltage side does not become equal to or less than the threshold value for determining the low-voltage fault 1201, instead of the period 1203. Furthermore, the voltage input function anomaly detection unit 212 can determine that no fault is present if the differential voltage output by the drive voltage input unit 211, after the injection pulse is switched on, is equal to or less than the threshold value 1201 for determining the upstream low-voltage fault.

[0119] Furthermore, the differential voltage value is compared with the threshold value 1201 for determining the upstream low-voltage fault in order to perform the fault determination in the example above. For example, a differential voltage value in a normal state (normal differential voltage value) can be measured in advance, and then it can be determined that a fault exists if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault exists if the difference is not equal to or greater than the certain value.

[0120] As with reference to Fig. As described in section 12, in the fuel injection control device 127, the voltage difference information is based on the voltage difference obtained by subtracting the upstream voltage from the downstream voltage, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal (the upstream low voltage fault) when the voltage difference information output by the voltage measuring unit (drive voltage input unit 212) at a supply time of the second voltage during a control period (period in which the injection pulse is switched on) of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve.The voltage difference is not equal to or less than the threshold (threshold for determining the upstream low-voltage fault 1201), so that the voltage difference information is assumed to be equal to or less than when the voltage measuring unit is normal at the supply time (time T1 to time T3) of the second voltage during the control period. In this way, the upstream low-voltage fault can be adequately detected.

[0121] Next, a procedure for determining an error during the FastFall period is described.

[0122] Fig. Figure 13 is a view describing a fault detection procedure during the FastFall period according to the embodiment.

[0123] During the FastFall period after the application of a peak current (after time T3), a downstream high-voltage fault, a downstream low-voltage fault, and an upstream high-voltage fault can be detected. During the FastFall period, switching element 303 on the high-voltage side, switching element 304 on the low-voltage side, and switching element 305 on the downstream side are switched off, similar to a period after the injection pulse is switched off, and the high voltage 210 is applied to the solenoid 405 in the opposite direction to that at the time of application. Thus, a downstream voltage becomes a high voltage and an upstream voltage becomes a low voltage.Therefore, the voltage input function anomaly detection unit 212 performs a fault determination based on a differential voltage during a predetermined period 1302 after time T3, at which the switching element 303 on the high-voltage side, the switching element 304 on the low-voltage side and the switching element 305 on the downstream side are switched off.

[0124] For example, if the differential voltage during period 1302 is not equal to or greater than the threshold of 901 for the downstream low-voltage fault, the voltage input function anomaly detection unit 212 determines that the downstream low-voltage fault occurs. Furthermore, the voltage input function anomaly detection unit 212 determines that the downstream high-voltage fault occurs if the differential voltage during period 1302 is not equal to or less than the threshold of 1001 for the downstream high-voltage fault. Furthermore, the voltage input function anomaly detection unit 212 determines that the upstream high-voltage fault occurs if the differential voltage during period 1302 is not equal to or greater than the threshold of 1101 for the upstream high-voltage fault.

[0125] The voltage input function anomaly detection unit 212 can determine that there is no fault if the differential voltage is equal to or greater than the threshold 901 for downstream low-voltage faults, equal to or less than the threshold 1001 for downstream high-voltage faults, or equal to or greater than the threshold 1101 for upstream high-voltage faults.

[0126] Furthermore, the differential voltage value is compared with the threshold value to perform the fault determination in the example above. For example, a differential voltage value in a normal state (normal differential voltage value) can be measured in advance, and then it can be determined that a fault exists if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault exists if the difference is not equal to or greater than the certain value.

[0127] As with reference to Fig. As described in Figure 13, in the fuel injection control device 127, the anomaly detection unit determines that the output of the voltage measuring unit is abnormal (the downstream low-voltage fault occurs) if the voltage difference information output by the voltage measuring unit at a supply stop time (period 1302) of the first voltage and the second voltage during a control period (period in which the injection pulse is set to ON) of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve is not equal to or greater than the threshold (threshold 901 for downstream low-voltage fault), such that the voltage difference information is assumed to be equal to or greater thanAs if the voltage measuring unit is normal at the supply stop time of the first and second voltages during the control period, and determines that the output of the voltage measuring unit is abnormal (the downstream high-voltage fault occurs) if the voltage difference information is not equal to or less than the threshold (threshold 1001 for downstream high-voltage fault), then the voltage difference information is assumed to be equal to or less than when the voltage measuring unit is normal at the supply stop time of the first and second voltages during the control period. In this way, the downstream low-voltage fault and the downstream high-voltage fault can be adequately detected.

[0128] Next, a method for determining a fault during the excitation of a holding current is described.

[0129] Fig. Figure 14 is a view describing a fault detection method during the excitation of a holding current according to the embodiment.

[0130] An upstream low-voltage fault can also occur during the excitation of the holding current when the injection pulse is switched on.

[0131] A period during excitation with the holding current corresponds to a period from time T4 to time T6, which is in Fig. Figure 8 is shown. During the duration of the holding current excitation, the switching element 304 on the low-voltage side is controlled to be repeatedly switched on and off. When the switching element 304 on the low-voltage side is switched on, an upstream voltage rises to a value corresponding to the battery voltage. Conversely, when the switching element 304 on the low-voltage side is switched off, the switching element 305 on the downstream side remains switched on, so that a downstream voltage becomes the ground voltage.

[0132] For this reason, it is difficult to determine the upstream low-voltage fault, since the differential voltage becomes zero when the switching element 304 on the low-voltage side is switched off. However, when the switching element 304 on the low-voltage side is switched on, the differential voltage becomes high, making it possible to determine the upstream low-voltage fault.

[0133] When an upstream low-voltage fault occurs, the differential voltage between a downstream and an upstream measurement voltage is always zero, as indicated by line 1402. Therefore, the voltage input function anomaly detection unit 212 determines that an upstream low-voltage fault is present when the differential voltage is not equal to or less than a threshold (threshold 1401 for determining upstream low-voltage fault), which is a value lower than the differential voltage value (line 1402) when an anomaly occurs. Furthermore, the voltage input function anomaly detection unit 212 can determine that no fault is present if the differential voltage during the excitation of the holding current is equal to or less than the threshold 1401 for determining upstream low-voltage fault.

[0134] As with reference to Fig. As described in 14, in the fuel injection control device 127, the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit at a supply time of the first voltage during a control period (period in which the injection pulse is set to ON) of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve is not equal to or less than a threshold (threshold 1401 for determining an upstream low voltage fault), such that the voltage difference information is assumed to be equal to or less than when the voltage measuring unit is normal at the supply time of the first voltage during the control period.In this way, the upstream low-voltage fault can be properly detected.

[0135] Since the behavior of the differential voltage varies as described above depending on the control state, it is possible to identify a cause of fault (e.g., a fault point) by measuring the differential voltage until the injection pulse is switched off at time T6 and then the high voltage 210 applied in the reverse direction converges as the injection pulse is switched on at time T1, and a fault diagnosis is carried out according to the drive state.

[0136] An example of a series of fault diagnosis processes according to the driving condition is given with reference to Fig. 8 described.

[0137] The voltage input function anomaly detection unit 212 detects an upstream low-voltage fault during a period between the time (time T1) when the injection pulse is switched on and the time (time T3) when the peak current is supplied.

[0138] Next, the voltage input function anomaly detection unit 212 determines a downstream low-voltage fault, a downstream high-voltage fault, and an upstream high-voltage fault during a period from the time (time T3) when the peak current is applied until the time (time T4) when the holding current is applied. As described above, it is possible to determine the type of fault by using different threshold values ​​to identify the respective faults.

[0139] During a period from time T4 to time T6, the voltage input function anomaly detection unit 212 detects the upstream low voltage fault similarly to the period from time T1 to time T3.

[0140] Next, the voltage input function anomaly detection unit 212 determines the downstream low voltage fault, the downstream high voltage fault and the upstream high voltage fault after time T6, when the injection pulse is switched off.

[0141] Since all defects can be identified by observing the differential voltage in a single injection process by performing such a series of processes, it is possible to identify the defect at a high frequency and to appropriately determine the shape of the defect.

[0142] Furthermore, the unit 212 for detecting voltage input function anomalies can detect the downstream high-voltage fault and the upstream high-voltage fault during the period between time T1 and time T3. It can also detect the downstream high-voltage fault and the upstream high-voltage fault during the period between time T4 and time T6. Moreover, the device 212 for detecting voltage input function anomalies does not necessarily have to perform the entire fault detection described above, but can also perform only a part of it.

[0143] Next, fault detection is described in a case where a configuration of the internal combustion engine system 100 is a configuration in which a leakage current is generated on the upstream side and the downstream side of the solenoid 405 of the fuel injection valve 105.

[0144] In the configuration where the leakage current is generated on the upstream and downstream sides of the solenoid 405 of the fuel injection valve 105, a downstream low-voltage fault, a downstream high-voltage fault, an upstream low-voltage fault, and an upstream high-voltage fault can be detected after the injection pulse is switched off or during the FastFall period when the injection pulse is switched on.

[0145] This section describes the leakage current.

[0146] Fig. Figure 15 is a view describing a voltage change caused by a leakage current according to the embodiment.

[0147] The leakage current flows into the solenoid 405 of the fuel injection valve 105 from an input side of the switching element 303 on the high-voltage side or of the switching element 304 on the low-voltage side. Therefore, in a state where the switching elements 303, 304, and 305 are switched off, the upstream voltage and the downstream voltage of the solenoid 405 of the fuel injection valve 105 increase by the rise voltages 1502 and 1501, respectively.

[0148] Since the magnitude of the rise voltage is the same on both the upstream and downstream sides, a differential voltage obtained by subtracting an upstream measurement voltage from a downstream measurement voltage is not affected by the voltage change caused by the leakage current. However, if the drive voltage input unit 211 or similar fails, the voltage change caused by the leakage current appears in the differential voltage, making it possible to identify a fault point based on the voltage change.

[0149] Next, a fault detection procedure for a downstream fault is described based on the leakage current.

[0150] Fig. Figure 16 is a view describing a fault detection method for a downstream fault using a leakage current according to the embodiment.

[0151] First, it is described how a downstream low-voltage fault can be detected. After the injection pulse is switched off, a downstream measurement voltage becomes a low voltage when the downstream low-voltage fault occurs. Consequently, a differential voltage becomes the voltage indicated by line 1601. Therefore, the voltage input function anomaly detection unit 212 determines that the downstream low-voltage fault occurs when the differential voltage after the injection pulse is switched off is not equal to or greater than a threshold value 1602 for determining the downstream low-voltage fault, which has a higher value than the voltage indicated by line 1601.Furthermore, the voltage input function anomaly detection unit 212 can determine that no fault is present if the differential voltage value is equal to or greater than the threshold value 1602 for determining the downstream low voltage fault.

[0152] Furthermore, the differential voltage value is compared with the threshold value to perform the fault determination in the example above. For example, a differential voltage value in a normal state (normal differential voltage value) can be measured in advance, and then it can be determined that a fault exists if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault exists if the difference is not equal to or greater than the certain value.

[0153] As described above, in the fuel injection control device 127, the anomaly detection unit determines that the output of the voltage measuring unit is abnormal (the downstream low-voltage fault) if the voltage difference information output by the voltage measuring unit at a predetermined time after a control period (period in which the injection pulse is switched on) of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve is not equal to or greater than the threshold (threshold 1602 for determining the downstream low-voltage fault) such that the voltage difference information is assumed to be equal to or less than when the voltage measuring unit is normal at the predetermined time.In this way, the downstream low-voltage fault can be adequately detected.

[0154] Next, the determination of a downstream high-voltage fault is described. When the downstream high-voltage fault occurs, a differential voltage is applied to the high-voltage side. However, this differential voltage decreases from the high-voltage voltage value due to a voltage change caused by a leakage current, as indicated by line 1603, since the voltage change on the upstream side is due to the leakage current. Therefore, the voltage input function anomaly detection unit 212 determines that the downstream high-voltage fault occurs when the differential voltage is not equal to or less than a threshold value 1604 for determining the downstream high-voltage fault, which is lower than the voltage value indicated by line 1603.In addition, the voltage input function anomaly detection unit 212 can determine that there is no fault if the differential voltage value is equal to or less than the threshold value 1604 for determining the downstream high voltage fault.

[0155] Furthermore, the differential voltage value is compared with the threshold value to perform the fault determination in the example above. For example, a differential voltage value in a normal state (normal differential voltage value) can be measured in advance, and then it can be determined that a fault exists if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault exists if the difference is not equal to or greater than the certain value.

[0156] As described above, in the fuel injection control device 127, the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit at a predetermined time after a control period (period in which the injection pulse is switched on) of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve is not equal to or less than the threshold (threshold 1604 for determining the downstream high-voltage fault), such that the voltage difference information is assumed to be equal to or less than when the voltage measuring unit is normal at the predetermined time. In this way, the downstream high-voltage fault can be adequately detected.

[0157] Next, a fault detection procedure for an upstream fault is described based on the leakage current.

[0158] Fig. Figure 17 is a view describing a fault detection method for an upstream fault using a leakage current according to the embodiment.

[0159] First, it is described how an upstream low-voltage fault can be detected. When the upstream low-voltage fault occurs, an upstream measurement voltage becomes a low voltage, so that a differential voltage increases due to a voltage rise caused by a leakage current, as indicated by line 1701. Therefore, the voltage input function anomaly detection unit 212 determines that the upstream low-voltage fault occurs when the differential voltage after the injection pulse is switched off does not become equal to or greater than a threshold value 1702 for determining the upstream low-voltage fault, which has a lower value than the voltage indicated by line 1701.Furthermore, the voltage input function anomaly detection unit 212 can determine that no fault is present if the differential voltage value is equal to or less than the threshold value 1702 for determining the upstream low voltage fault.

[0160] Furthermore, the differential voltage value is compared with the threshold value to perform the fault determination in the example above. For example, a differential voltage value in a normal state (normal differential voltage value) can be measured in advance, and then it can be determined that a fault exists if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault exists if the difference is not equal to or greater than the certain value.

[0161] Next, the determination of an upstream high-voltage fault is described. When the upstream high-voltage fault occurs, an upstream measurement voltage becomes a high voltage, and thus a differential voltage becomes a negative voltage. However, this negative voltage is increased by a voltage rise due to leakage current, as indicated by line 1703, because a downstream voltage also increases due to the leakage current. Therefore, the voltage input function anomaly detection unit 212 determines that the upstream high-voltage fault occurs when the differential voltage after the injection pulse is switched off is not equal to or greater than a threshold value 1704 for determining the upstream high-voltage fault, which has a higher value than the voltage value indicated by line 1703.In addition, the voltage input function anomaly detection unit 212 can determine that there is no fault if the differential voltage is equal to or greater than the threshold 1704 for determining the upstream high voltage fault.

[0162] Furthermore, the differential voltage value is compared with the threshold value to perform the fault determination in the example above. For example, a differential voltage value in a normal state (normal differential voltage value) can be measured in advance, and then it can be determined that a fault exists if the difference between a measured differential voltage value and the normal differential voltage value is equal to or greater than a certain value, and it can be determined that no fault exists if the difference is not equal to or greater than the certain value.

[0163] If the voltage influenced by the leakage current is used in this way, it is possible to detect a fault with respect to the differential voltage after the injection pulse has been switched off, it is possible to differentiate a type of fault and it is possible to simplify the fault diagnosis logic.

[0164] As described above, the fuel injection control device 127 according to the present embodiment is the fuel injection control device 127 comprising: the first voltage supply unit (fuel injection drive unit 207a) which provides the first voltage (low voltage); the second voltage supply unit (fuel injection drive unit 207a) which provides the second voltage (high voltage), which is higher than the first voltage;and a fuel injection control unit (the drive IC 208 and the control unit 200) that controls the second voltage supply unit to supply the second voltage to a coil to open a fuel injection valve 105, which has the coil (solenoid 405), and that controls the first voltage supply unit to supply the first voltage to the coil to maintain an open state of the fuel injection valve 105, and includes: the voltage measurement unit (drive voltage input unit 211), which measures and outputs voltage information based on an upstream voltage of the coil of the fuel injection valve and a downstream voltage of the coil; a correction unit (the fuel injection quantity correction unit 213), which corrects a fuel injection quantity of the fuel injection valve based on the voltage information output by the voltage measurement unit;and an anomaly detection unit (the voltage input function anomaly detection unit 212) which, based on the voltage information output by the voltage measurement unit, detects whether an output of the voltage measurement unit is abnormal.

[0165] With this configuration, it is possible to adequately detect the anomaly in the voltage information output by the voltage measuring unit, which is the basis for correcting the fuel injection quantity.

[0166] Furthermore, the present invention is not limited to the embodiment described above and can be suitably modified and implemented within a scope that does not deviate from the scope of protection of the present invention.

[0167] For example, control lines and information lines deemed necessary for the description have been shown in the embodiment above, and it is difficult to say that all control lines and information lines required for a product are shown. It can be assumed that most configurations are practically interconnected.

[0168] In the embodiment described above, if an anomaly is detected in the output of the drive voltage input unit 211, the anomaly detection unit 212 for the voltage input function can store information (e.g., a type of fault) indicating the anomaly in a memory device (not shown) within the ECU 109. In this case, the information stored in the memory device indicating the anomaly can be read and displayed by a test device connected to the ECU 109 during vehicle inspection. It is then possible to detect, from the information displayed in the memory device, that an anomaly exists in the output of the drive voltage input unit 211.

[0169] Furthermore, some or all of the processes performed by the microcomputer that forms the control unit 200 in the above embodiment can be performed by another hardware circuit. Reference symbol list 100 internal combustion engine systems 101 Engine 105 Fuel injection valve 109 ECU 127 Fuel injection control unit 200 control unit 201 Pulse signal calculation unit 202 Drive shaft shape control unit 207a Fuel injection drive unit 211 Drive voltage input unit 212 Voltage Input Function Anomaly Detection Unit 213 Fuel injection quantity correction unit 405 Solenoid

Claims

Fuel injection control device comprising: a first voltage supply unit that provides a first voltage; a second voltage supply unit that provides a second voltage higher than the first voltage; a fuel injection control unit that controls the second voltage supply unit to supply the second voltage to a coil to open a fuel injection valve having the coil, and that controls the first voltage supply unit to supply the first voltage to the coil to maintain an open state of the fuel injection valve; a voltage measuring unit that measures and outputs voltage information based on an upstream voltage of the coil of the fuel injection valve and a downstream voltage of the coil;a correction unit that corrects the fuel injection quantity of the fuel injection valve based on the voltage information output by the voltage measuring unit; and an anomaly detection unit that detects whether an output of the voltage measuring unit is abnormal based on the voltage information output by the voltage measuring unit. Fuel injection control device according to claim 1, wherein the voltage information is a voltage difference information based on a voltage difference between the upstream voltage and the downstream voltage. Fuel injection control device according to claim 2, wherein the anomaly detection unit compares voltage difference information output by the voltage measuring unit at a predetermined time after the end of a control period of the voltage supply by the first voltage supply unit and the second voltage supply unit for valve opening control of the fuel injection valve, and a predetermined threshold value relating to the voltage difference information to determine whether a predetermined output of the voltage measuring unit at the predetermined time is abnormal, and determines, based on a comparison result, whether the output of the voltage measuring unit is abnormal. Fuel injection control device according to claim 3, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the upstream voltage from the downstream voltage, the threshold is a lower threshold such that the voltage difference information is assumed to be equal to or greater than the lower threshold if the output of the voltage measuring unit is normal at the predetermined time, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit is not equal to or greater than the lower threshold at the predetermined time. Fuel injection control device according to claim 3, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the upstream voltage from the downstream voltage, the threshold is an upper threshold such that the voltage difference information is assumed to be equal to or less than the lower threshold when the output of the voltage measuring unit is normal at the predetermined time, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal when the voltage difference information output by the voltage measuring unit is not equal to or less than the lower threshold at the predetermined time. Fuel injection control device according to claim 2, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the upstream voltage from the downstream voltage, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit at a supply time of the second voltage during a control period of the voltage supply by the first voltage supply unit and the second voltage supply unit for valve opening control of the fuel injection valve is not equal to or less than a threshold value, such that the voltage difference information is equal to or less than when the voltage measuring unit is normal at the supply time of the second voltage during the control period.Fuel injection control device according to claim 2, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the downstream voltage from the downstream voltage, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit at a supply stop time of the first voltage and the second voltage during a control period of the voltage supply by the first voltage supply unit and the second voltage supply unit for valve opening control of the fuel injection valve is not equal to or less than a threshold such that the voltage difference information is assumed to be equal to or greater thanif the voltage measuring unit is normal at the supply stop time of the first voltage and the second voltage during the control period. Fuel injection control device according to claim 2, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the upstream voltage from the downstream voltage, and the anomaly detection unit determines that the output of the voltage measuring unit is anomalous if the voltage difference information output by the voltage measuring unit at a supply stop time of the first voltage and the second voltage during a control period of the voltage supply by the first voltage supply unit and the second voltage supply unit for valve opening control of the fuel injection valve is not equal to or less than a threshold such that the voltage difference information is assumed to be equal to or less thanas if the voltage measuring unit is normal at the supply stop time of the first voltage and the second voltage during the control period. Fuel injection control device according to claim 2, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the upstream voltage from the downstream voltage, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit at a supply time of the first voltage during a control period of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve is not equal to or less than a threshold such that the voltage difference information is assumed to be equal to or less thanas if the voltage measuring unit is normal at the time of the first voltage supply during the control period. Fuel injection control device according to claim 2, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the upstream voltage from the downstream voltage, a leakage current flows into an upstream side and a downstream side of the coil, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit at a predetermined time after a control period of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve is not equal to or greater than a threshold such that the voltage difference information is assumed to be equal to or less thanas if the voltage measuring unit is normal at the predetermined time. Fuel injection control device according to claim 2, wherein the voltage difference information is voltage difference information based on a voltage difference obtained by subtracting the upstream voltage from the downstream voltage, a leakage current flows into an upstream side and a downstream side of the coil, and the anomaly detection unit determines that the output of the voltage measuring unit is abnormal if the voltage difference information output by the voltage measuring unit at a predetermined time after a control period of the voltage supply by the first voltage supply unit and the second voltage supply unit for the valve opening control of the fuel injection valve is not equal to or less than the threshold such that the voltage difference information is assumed to be equal to or less thanas if the voltage measuring unit is normal at the predetermined time. Fuel injection control device according to claim 1, wherein the correction unit stops the correction of the fuel injection quantity based on the voltage information output by the voltage measuring unit when the anomaly detection unit determines that the output of the voltage measuring unit is abnormal. Fuel injection control device according to claim 1, wherein the anomaly detection unit stores information indicating the anomaly in a storage device when it detects that the output of the voltage measuring unit is abnormal. A method for controlling fuel injection, performed by a fuel injection control device, comprising: a first voltage supply unit that provides a first voltage; a second voltage supply unit that provides a second voltage higher than the first voltage; and a fuel injection control unit that controls the second voltage supply unit to supply the second voltage to a coil to open a fuel injection valve having the coil, and that controls the first voltage supply unit to supply the first voltage to the coil to maintain an open state of the fuel injection valve, wherein the method for controlling fuel injection comprises: measuring and outputting voltage information based on an upstream voltage of the coil of the fuel injection valve and a downstream voltage of the coil;Correcting the fuel injection quantity of the fuel injection valve based on voltage information; and detecting whether the voltage information is abnormal based on the voltage information.

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