Fuel injection control device and fuel injection control method

Abstract

Fuel injection control device for controlling a fuel injection device, wherein the fuel injection control device comprises: a control current generation unit designed to generate a control current for controlling the fuel injection device; a current sensing unit designed to detect a control current for the fuel injection device at each predetermined time, which is controlled based on the control current; and a current prediction unit designed to predict a third control current at a third time later than the second time, based on a first control current at a first time and a second control current at a second time later than the first time, each detected by the current detection unit; where The control current generation unit makes a comparison between a predicted amount of electrical power, calculated based on the third control current predicted by the current prediction unit at the third time, and a target amount of electrical power, calculated based on a predetermined target control current, in order to correct the control current.

Description

Technical field

[0001] The present disclosure relates to a fuel injection control device and a fuel injection control method. State of the art

[0002] In recent years, techniques such as lean combustion and exhaust gas recirculation (EGR) have been developed to reduce vehicle fuel consumption and increase emissions limits. Lean combustion technology operates a system with an air-fuel mixture that is leaner than a theoretical air / fuel ratio, while EGR technology works by recirculating a portion of the exhaust gas back into the system after combustion.

[0003] In an internal combustion engine, for the purpose of reducing fuel consumption and increasing emission limits, the amount of fuel or air in a combustion chamber deviates from a theoretical value, making a spark plug susceptible to fuel ignition failure.

[0004] Due to the need for low fuel consumption and high emissions control performance, the internal combustion engine is required to have a high degree of control over the air / fuel ratio to suppress misfires. It is therefore necessary for the internal combustion engine to minimize fluctuations in the amount of fuel injected by the fuel injection system.

[0005] PTL 1 discloses a fuel injection control device. Taking into account the amount of fuel injected by a fuel injection device from the time a fuel injection pulse transmitted to the fuel injection device is switched off until the actual closing of a piston of the fuel injection device, the fuel injection control device corrects a width of the fuel injection pulse to adjust the amount of fuel injected by the fuel injection device.

[0006] Furthermore, PTL 2 discloses a fuel injection control device that measures the current through a coil driving a piston of a fuel injection device and calculates a gradient of the measured current. Based on the current gradient, the fuel injection control device corrects for a deviation in the peak current flowing through the coil.

[0007] Furthermore, PTL 3 describes a fuel pump that draws fuel from a fuel tank and supplies it under pressure to a common rail. The fuel in the common rail is injected by a fuel injector. A target injection duration for the fuel injector is calculated based on the fuel pressure, detected by a fuel pressure sensor, and a target injection quantity. When a fuel injection occurs whose injection duration overlaps with a fuel pressure supply duration of the fuel pump, the amount of fuel pressure increase due to the pressure supply during the injection period is predicted based on several sampled fuel pressure values ​​detected by the fuel pressure sensor. The target injection duration is then set based on this fuel pressure increase.

[0008] PTL 4 describes a method for monitoring the opening of an injection valve. The injection valve comprises a valve body with a cavity having a fluid outlet section, a valve needle that is movable in the cavity between a closed position, which prevents fluid flow outlet, and other positions that allow fluid flow through the outlet, and an actuator unit for actuating the valve needle. The method includes actuating the actuator unit with a predetermined voltage signal, recording a time-dependent profile of a current through the actuator unit, detecting a first gradient change time during which the gradient of the recorded current profile changes more than a first threshold, detecting a second gradient change time during which the gradient of the recorded current profile changes more than a second threshold, and determining a diagnostic value.which can be used to compensate for long-term drift of the injection valve, based on the first and second gradient change times. PTL 5 describes a control device for an internal combustion engine that can stabilize the behavior when a fuel injection valve is opened and that can reduce variation in the amount of fuel injected by the fuel injection valve. The control device for an internal combustion engine includes a high-voltage differential sensing device for obtaining a difference between a predetermined reference voltage and a real high voltage detected by a high-voltage sensing device, and a drive current differential storage device for storing in advance the amount of the device differential variation of a real drive current detected by a drive current sensing device.and a drive control value correction device for correcting at least one target value of a drive current to a fuel injector and a target value of a drive time based on at least one result of the high-voltage differential detection device and the drive current differential storage device, and for correcting a target control value of the fuel injector based on at least one detection result of the change in the detected high voltage and the change in the current for driving the fuel injector.

[0009] PTL 6 describes a control device for an internal combustion engine, comprising at least the following: a battery that applies a battery voltage to the internal combustion engine; a first fuel injector that injects fuel directly into a combustion chamber; high-voltage generating means for amplifying the battery voltage to a set high voltage in order to generate a set high voltage; high-voltage detection means for detecting an actual high voltage generated by the high-voltage generating means; fuel injector actuation means for supplying either the actual high voltage detected by the high-voltage detection means or the battery voltage to the first fuel injector with a set time specification in order to actuate the fuel injector; and actuation current detection means for detecting an actuation current of the first fuel injector.

[0010] PTL 7 describes a fuel injection control device for an internal combustion engine and describes the following configuration of the device: a first approximation line LA1 is obtained using electrical current values ​​ID1 and ID2, which are sampled at first and second times tS1 and tS2, which are set before a region of the normal valve opening time of a fuel injector; a second approximation line LA2 is obtained using electrical current values ​​ID3 and ID4, which are sampled at third and fourth times tS3 and tS4, which are set after the region of the normal valve opening time;and the estimated valve opening time, which approximates the actual valve opening time of the fuel injector, is calculated by obtaining the time corresponding to an inflection point of the current change characteristic by identifying an intersection of the first approximation line LA1 and the second approximation line LA2. List of patent documents PTL 1: JP 2004 - 176 546 A PTL 2: JP 2015 - 227 620 A PTL 3: DE 10 2006 000 530 A1 PTL 4: US 2015 / 0 108 238 A1 PTL 5: US 2015 / 0 144 109 A1 PTL 6: EP 2 865 870 A1 PTL 7: JP 2014 - 31 790 A Summary of the inventionTechnical problem

[0011] However, the actual increase in high current required to open the piston of the fuel injection device is not linear due to the mechanical properties of the fuel injection device. Thus, the fuel injection control device disclosed in PTL 1 and PTL 2 exhibits fluctuations in controlling the piston opening, resulting in less precise control of the injected fuel quantity.

[0012] In view of the aspects described above, one object of the present invention is to provide a fuel injection control device that controls the injected fuel quantity with higher accuracy. Solution to the problem

[0013] To solve the problems described above, the present invention provides a fuel injection control device for controlling a fuel injection device. The fuel injection control device comprises: a control current generation unit designed to generate a control current for controlling the fuel injection device; a current sensing unit designed to detect a control current for the fuel injection device at each predetermined time, which is controlled based on the control current; and a current prediction unit designed to predict a third control current at a third time later than the second time, based on a first control current at a first time and a second control current at a second time later than the first, each detected by the current sensing unit.In this configuration, the control current generation unit makes a comparison between the predicted electrical power, calculated based on the third control current predicted by the current prediction unit at the third time, and the target electrical power, calculated based on a predetermined target control current, in order to correct the control current. Advantageous effects of the invention

[0014] The present invention provides a fuel injection control device that controls the injected fuel quantity with higher accuracy. Description [ Fig. 1] Fig. Figure 1 is a representation showing a main part configuration of an internal combustion engine according to one embodiment and an electronic control unit (ECU) according to the embodiment. [ Fig. 2] Fig. Figure 2 is a representation showing a function of a fuel injection controller. [ Fig. 3] Fig. Figure 3 is a block diagram showing a functional configuration of the electronic control unit (ECU). [ Fig. 4] Fig. Figure 4 is a sectional view showing a configuration of a fuel injection device. [ Fig. 5] Fig. Figure 5 is a representation showing a method for correcting the fuel injection pulse by the fuel injection controller. [ Fig. 6] Fig. Figure 6 is a flowchart of a procedure for controlling a fuel injection device by the fuel injection controller. Description of embodiments [internal combustion engine]

[0015] First, an electronic control unit (ECU) 1 and an internal combustion engine 100, each according to an embodiment of the present invention, are described. The electronic control unit (hereinafter referred to as ECU) 1 comprises a fuel injection controller 82 and controls the internal combustion engine 100. The internal combustion engine 100 can have a single cylinder or multiple cylinders. The embodiment describes, by way of example, a case in which the four-cylinder internal combustion engine 100 has a fuel injection device 400 and the quantity of fuel injected by the fuel injection device 400 is controlled.

[0016] Fig. Figure 1 is a representation that depicts a main part configuration of the internal combustion engine 100 and the ECU 1.

[0017] As it is in Fig. As shown in Figure 1, air drawn in from outside into the internal combustion engine 100 flows through an air cleaner 110, an intake pipe 111, and an intake manifold 112, and flows into each of the cylinders 150. The quantity of air flowing into each of the cylinders 150 is regulated by a throttle valve 113, and the quantity of air regulated by the throttle valve 113 is measured by a flow sensor 114.

[0018] The throttle valve 113 includes a throttle opening sensor 113a for detecting an opening of the throttle valve 113, and information on the opening of the throttle valve 113, detected by the throttle opening sensor 113a, is output to the ECU (electronic control unit) 1.

[0019] Here, the throttle valve 113 is an electronic throttle valve driven by an electric motor, but any other system capable of adequately adjusting the airflow rate can be used.

[0020] The temperature of the gas flowing into each of the cylinders 150 is detected by an intake air temperature sensor 115.

[0021] A ring gear 120 is mounted on a crankshaft 123, and a crank angle sensor 121 is arranged on a radially outer side of the ring gear 120. The crank angle sensor 121 detects the rotation angle of the crankshaft 123. In this embodiment, the crank angle sensor 121 detects the rotation angle of the crankshaft 123 every 10 degrees of rotation and during each combustion cycle.

[0022] A water temperature sensor 122 is provided on a water jacket (not shown) of a cylinder head and the water temperature sensor 122 detects the temperature of the cooling water for the internal combustion engine 100.

[0023] The vehicle also includes an accelerator pedal position sensor (APS) 126. The accelerator pedal position sensor 126 detects a displacement (depression) of the accelerator pedal 125, thereby detecting a driver request torque. The driver request torque detected by the accelerator pedal position sensor 126 is output to the ECU 1, as described later. The ECU 1 controls the throttle valve 113 based on the driver request torque.

[0024] Fuel is stored in a fuel tank 130 and is pumped and pressurized by a fuel pump 131. The fuel then flows through a fuel line 133, which is equipped with a pressure regulator 132, to be drawn to the fuel injection device 400. The pressure regulator 132 sets the fuel output from the fuel pump 131 to a predetermined pressure, and the fuel injection device 400 injects the fuel into each of the cylinders 150.

[0025] The fuel injection device 400 is controlled based on a fuel injection pulse (control signal) from the fuel injection controller 82 of the ECU 1, as described later.

[0026] Excess fuel, which is set to the predetermined pressure by the pressure regulator 132, is returned to the fuel tank 130 via a return line (not shown).

[0027] This section describes a specific configuration of the fuel injection device 400.

[0028] Fig. Figure 2 is a sectional view showing the configuration of the fuel injection device 400.

[0029] The fuel injection device 400 is mounted on one side of a nozzle 405 on a cylinder head 420 and an area between the nozzle 405 and the cylinder head 420 is sealed with a ring seal 412 and a tip seal 407.

[0030] In the nozzle 405, a piston 410 is arranged to be displaceable along an axial direction of a central axis X1.

[0031] The fuel injection controller 82 sends a fuel injection pulse S9 (control signal), based on which current is supplied to a coil 402 via a power line 419. This generates an electromagnetic force in the coil 402, causing the piston 410 to resist the pressure force exerted by a spring 413 and move in a direction A along the central axis X1. In this state, the piston 410 is guided by a guide 408 and a guide 411.

[0032] This configuration forms a gap between the tip of the piston 410 and an opening cup 409, thereby opening the fuel injection device 400. The amount of movement of the piston 410 relative to the opening cup 409 is referred to as the stroke.

[0033] In the fuel injection device 400, the stroke of the piston 410 is controlled according to the amount of current based on the fuel injection pulse S9. The amount of fuel injected by the fuel injection device 400 is controlled according to the stroke of the piston 410.

[0034] When the fuel injection pulse S9 transmitted by the fuel injection controller 82 ends at the fuel injection device 400, the current supplied to the coil 402 stops and no electromagnetic force is generated in the coil 402. The piston 410 is therefore pushed by the spring 413 in a direction B along the central axis X1.

[0035] In this configuration, the tip of the piston 410 closes a through-hole in the opening cup 409, thereby closing the fuel injection device 400. In this state, the fuel injection device 400 stops injecting fuel from the gap between the piston 410 and the opening cup 409.

[0036] The direction of arrow A along the central axis X1 (as described previously) is referred to as the opening direction of the fuel injection device 400. The direction of arrow B (as described previously) is referred to as the closing direction of the fuel injection device 400.

[0037] With further reference to Fig. Figure 1 of the internal combustion engine 100 includes the cylinder head (not shown) in which a cylinder pressure sensor (CPS; also referred to as an in-cylinder pressure sensor) 140 is arranged. The cylinder pressure sensor 140 is located in each of the cylinders 150 and detects the internal pressure (combustion pressure) of the corresponding cylinder 150.

[0038] The cylinder pressure sensor 140 is a piezoelectric pressure sensor or a differential pressure sensor and is designed to detect the combustion pressure (internal cylinder pressure) of each of the cylinders 150 in a wide temperature range.

[0039] Each of the cylinders 150 has an exhaust manifold 160 for releasing combustion gases (exhaust gas) from the corresponding cylinder 150. The exhaust manifold 160 has a three-way catalytic converter 161 on its exhaust side. The exhaust gas is cleaned by the three-way catalytic converter 161 and then released into the atmosphere.

[0040] An upstream air / fuel ratio sensor 162 is arranged upstream of the three-way catalytic converter 161. The upstream air / fuel ratio sensor 162 continuously detects the air / fuel ratio of the exhaust gas emitted by each of the cylinders 150.

[0041] A downstream air / fuel ratio sensor 163 is arranged following the three-way catalyst 161. The downstream air / fuel ratio sensor 163 outputs a detection signal that is generally switched on / off near the theoretical air / fuel ratio. In this embodiment, the downstream air / fuel ratio sensor 163 is an O2 sensor.

[0042] In addition, a spark plug 200 is located at the top of each of the cylinders 150. The spark plug 200 discharges (sparks) to ignite an air-fuel mixture in each of the cylinders 150, causing an explosion in the corresponding cylinder 150. In this state, a piston 170 is pushed downwards. When the piston 170 is pushed downwards, the crankshaft 123 rotates.

[0043] Each of the various sensors described above, such as the throttle position sensor 113a, the flow sensor 114, the crankshaft position sensor 121, the accelerator pedal position sensor 126, the water temperature sensor 122, and the cylinder pressure sensor 140, outputs a signal to the ECU 1. The ECU 1 detects the operating condition of the internal combustion engine 100 based on the output signal from each of the various sensors and controls the amount of air sent to each of the cylinders 150, the amount of fuel injected by the fuel injection device 400, the ignition timing of the spark plug 200, and so on. [ECU Hardware Configuration]

[0044] Next, the complete hardware configuration of the ECU 1 will be described.

[0045] As it is in Fig. As shown in Figure 1, the ECU 1 comprises an analog input section 10, a digital input section 20, an A / D converter (analog / digital converter) 30, a RAM (random access memory) 40, an MPU (microprocessing unit) 50, a ROM (read-only memory) 60, an I / O port (input / output port) 70 and an output circuit 80.

[0046] The analog input section 10 receives an analog output signal from each of the various sensors, such as the throttle opening sensor 113a, the flow sensor 114, the accelerator pedal position sensor 126, the upstream air / fuel ratio sensor 162, the downstream air / fuel ratio sensor 163, the cylinder pressure sensor 140 and the water temperature sensor 122.

[0047] The analog input section 10 is connected to the A / D converter 30. The analog output signal from each of the various sensors is fed into the analog input section 10 and subjected to signal processing, e.g., noise reduction. Subsequently, the analog output signal is converted into a digital signal by the A / D converter 30 and stored in the RAM 40.

[0048] The digital input section 20 receives a digital output signal from the crank angle sensor 121.

[0049] The digital input section 20 is connected to the I / O port 70. The digital output signal is input into the digital input section 20 and stored in the RAM 40 via the I / O port 70.

[0050] Each of the output signals stored in the RAM 40 is subjected to an arithmetic operation in the MPU 50.

[0051] The MPU 50 executes a control program (not shown) stored in the ROM 60 and performs the arithmetic operation for each of the output signals stored in the RAM 40 based on the control program. The MPU 50 calculates a control value based on the control program. The control value specifies the actuation amount of each actuator that drives the internal combustion engine 100 (e.g., the throttle valve 113, the pressure regulator 132, or the spark plug 200) and is temporarily stored in the RAM 40.

[0052] The control value, which specifies the actuation amount of the actuator and is stored in RAM 40, is then output to the output circuit 80 via the I / O port 70.

[0053] The output circuit 80 includes functions such as the fuel injection controller 82 (see Fig. 3) to control the actuation of piston 410 (see Fig. 2) the fuel injection device 400 and an ignition controller 83 (see Fig. 3) to control the voltage applied to spark plug 200. [Function block of the ECU]

[0054] Next, a functional configuration of the ECU 1 will be described.

[0055] Fig. Figure 3 is a block diagram showing the functional configuration of ECU 1.

[0056] Fig. Figure 4 is a representation showing a function of the fuel injection controller 82.

[0057] In ECU 1, the MPU 50 executes the control program stored in the ROM 60 to achieve various functions in the output circuit 80. This configuration causes the fuel injection controller 82 in the output circuit 80 to control the fuel injection device 400, and the ignition controller 83 in the output circuit 80 to control the discharge of the spark plug 200.

[0058] As it is in Fig. As shown in Figure 3, the output circuit 80 in the ECU 1 comprises a total controller 81, the fuel injection controller 82 and the ignition controller 83.

[0059] The overall controller 81 is connected to the accelerator pedal position sensor 126 and the cylinder pressure sensor 140 and receives the driver request torque (an acceleration signal S1) from the accelerator pedal position sensor 126 and an output signal S2 from the cylinder pressure sensor 140. [Overall Controller]

[0060] The overall controller 81 performs overall control of the fuel injection controller 82 and the ignition controller 83 based on the driver request torque (acceleration signal S1) from the accelerator pedal position sensor 126 and the output signal S2 from the cylinder pressure sensor 140. [Ignition controller]

[0061] The ignition controller 83 is connected to and receives information from the overall controller 81, a cylinder discrimination section 84, an angle information generation section 85, a speed information generation section 86, a load information generation section 88 and a water temperature measurement section 89.

[0062] Based on the received information, the ignition controller 83 calculates a current quantity (angle of current flow) supplied to a primary coil 310 of an ignition coil 300, a time to start the current flow and a time to switch off the current supplied to the primary coil 310 (ignition time).

[0063] Then, based on the amount of current flow, the time to start the current flow and the calculated ignition time, the ignition controller 83 outputs an ignition signal S to the primary coil 310 of the ignition coil 300 to control the discharge of the spark plug 200. [Fuel injection controller]

[0064] The fuel injection controller 82 is connected to the cylinder discrimination section 84, the angle information generation section 85, and the speed information generation section 86. The cylinder discrimination section 84 distinguishes each of the cylinders 150 of the internal combustion engine 100 and provides cylinder discrimination information S3 to the fuel injection controller 82. The angle information generation section 85 measures a crank angle of the crankshaft 123 and provides crank angle information S4 to the fuel injection controller 82. The speed information generation section 86 measures an engine speed and provides engine speed information S5 to the fuel injection controller 82.

[0065] Furthermore, the fuel injection controller 82 is connected to an intake air flow meter 87, a load information generation section 88, and a water temperature meter 89. The intake air flow meter 87 measures the intake air volume taken into each of the cylinders 150 and provides the intake air flow information S6 to the fuel injection controller 82. The load information generation section 88 measures the engine load and provides the engine load information S7 to the fuel injection controller 82. The water temperature meter 89 measures the temperature of the engine coolant and provides coolant temperature information S8 to the fuel injection controller 82.

[0066] Based on the received information, the fuel injection controller 82 calculates the amount of fuel injected by the fuel injection device 400 and the time required for the fuel injection. Then, based on the calculated amount and time of fuel injection, the fuel injection controller 82 generates the fuel injection pulse S9 and transmits it to the fuel injection device 400.

[0067] As it is in Fig. As shown in Figure 4, the fuel injection controller 82 comprises an arithmetic operations section 821, a correction section 822, a fundamental waveform detection section 823, an analog-to-digital converter 824, and a digital-to-analog converter 825.

[0068] The fundamental waveform acquisition section 823 acquires a fundamental waveform (a digital signal) of the fuel injection pulse S9 from the ROM 60 according to the operating state (target driving force) of the internal combustion engine 100. The fundamental waveform of the fuel injection pulse S9 is prepared in a variety of forms according to the operating state and stored in a storage medium such as the ROM 60.

[0069] The fundamental waveform of the fuel injection pulse S9 has a high current S91 and a holding current S92 (see Fig. 5) The high-current S91 is set to a high current value to cause the piston 410 of the fuel injection device 400 to open from a closed position. The holding current S92 is maintained within a constant range of current values ​​lower than the high-current S91 to keep the piston 410 (which has been opened) in an open position.

[0070] In the fuel injection controller 82, the fundamental waveform (the digital signal) of the fuel injection pulse S9, which is detected by the fundamental waveform detection section 823, is converted by the D / A converter 825 into an analog signal, i.e. a control current.

[0071] It should be noted that in a case where the fuel injection pulse S9 (the digital signal before the D / A conversion) is not specifically distinguished from the control current (the analog signal after the D / A conversion), the control current is referred to as control current S9.

[0072] The control current S9 is supplied to the fuel injection device 400 (coil 402) as the analog signal converted by the D / A converter 825. In the fuel injection device 400, the stroke of the piston 410 is controlled based on the control current S9.

[0073] An ammeter 430 is arranged at one end of the fuel injection device 400 (coil 402). The ammeter 430 measures a control current P (an analog value) that actually flows through the coil 402.

[0074] The control current P measured by the ammeter 430 is converted into a digital signal by the A / D converter 824 of the fuel injection controller 82 and then transmitted to the section for arithmetic operations 821.

[0075] It should be noted that in a case where the actual control current P flowing through the coil 402 (analog value measured by the ammeter 430) is not specifically distinguished from the control current after it has been converted into the digital signal by the A / D converter 824, the ‘control current’ P denotes the control current after conversion into the digital signal by the A / D converter 824.

[0076] The arithmetic operations section 821 detects an inflection point Pk of a waveform of the drive current based on the drive current P (see Fig. 5) for coil 402, wherein one is measured at a current measurement time specification and the other at a previous (last) measurement time specification.

[0077] Here, the waveform of the drive current P flowing through the coil 402 is determined according to the waveform of the control current S9 supplied to the coil 402. In this configuration, the arithmetic operations section 821 detects the inflection point Pk of the waveform of the drive current P (the waveform of the control current S9) based on results of previous measurements of the drive current P (measured at least two different times).

[0078] It should be noted that the inflection point Pk is a point where the gradient of a curve changes, and the waveforms from the inflection point Pk onwards can be approximated by a straight line.

[0079] If the Arithmetic Operations Section 821 determines that the drive current P measured at the current measurement time specification corresponds to the inflection point Pk, the Arithmetic Operations Section 821 uses linear extrapolation to calculate a predicted value of each of the drive currents P from the inflection point Pk.

[0080] Here, linear extrapolation is used to obtain a predicted subsequent value outside the numerical data range based on certain known numerical data.

[0081] Section 821 of Arithmetic Operations uses linear extrapolation to predict each of the drive currents P from the inflection point Pk and calculates an amount of electrical power based on the corresponding predicted drive current P. Section 821 then compares this amount of electrical power to an amount of electrical power calculated based on the control current S9 as the target value to estimate a time (time) ta at which the drive current P (predicted value) exceeds the control current S9 (target value). Here, each of the amounts of electrical power can be obtained as the area of ​​the drive current P or the control current S9 (see Area E in Fig. 5 as an example).

[0082] If the arithmetic operations section 821 determines that the control current P measured at a predetermined measurement time has already exceeded the control current S9, the arithmetic operations section 821 immediately stops the delivery of the fuel injection pulse S9 to the fuel injection device 400.

[0083] On the other hand, after determining that the control current P measured at the predetermined measurement time does not exceed the control current S9, the correction section 822 calculates the time at which the control current P should exceed the control current S9. Based on the time at which ta is determined, the correction section 822 corrects the control current S9 (fuel injection pulse S9) in either magnitude or duration.

[0084] The fundamental waveform detection section 823 and the arithmetic operations section 821, each described above and designed to detect and generate the control current S9, correspond to a control current generation unit according to the present invention. The configuration by which the control current P measured by the ammeter 430 is detected by the A / D converter 824 corresponds to a current detection unit according to the present invention. The arithmetic operations section 821, designed to predict the control current, corresponds to a current prediction unit according to the present invention. Furthermore, the correction of the control current S9 by the arithmetic operations section 821 and the correction section 822 corresponds to a correction of the control current by a control current generation unit according to the present invention. [Method for correcting the control current (fuel injection pulse)]

[0085] Next, a procedure for correcting the control current (fuel injection pulse) S9 by the above fuel injection controller 82 is described.

[0086] Fig. Figure 5 is a graph showing the procedure for correcting the fuel injection pulse S9 by the fuel injection controller 82. Fig. Figure 5 shows the control current P and the control current S9, and the predicted value of the control current P is shown with a dashed line.

[0087] In Fig. Figure 5 shows the graph in the upper section a relationship between the control current S9 after the D / A conversion (which is generated in the fuel injection controller 82) and the control current P for the fuel injection device 400 (coil 402), which is controlled based on the control current S9.

[0088] The control current S9 generated in the fuel injection controller 82 is primarily divided into the high current S91 and the holding current S92. The high current S91 is designed to cause the piston 410 of the fuel injection device 400 to open from the closed position at a predetermined angle. The holding current S92 is designed to keep the piston 410 in the open position.

[0089] The graph in the lower section of Fig. Figure 5 shows the measurement time specification for the control current P. The control current P is measured at the predetermined measurement time specification, which is based on a predetermined clock frequency. In particular, the control current P is measured at a predetermined clock drop time specification.

[0090] In the following, the predetermined clock drop time specification is referred to as the measurement time specification ADC.

[0091] As it is in Fig. As shown in Figure 5, the fuel injection controller 82 controls the fuel injection device 400 based on the control current S9, into which the fuel injection pulse S9 (detected by the fundamental waveform detection section 823) has been converted D / A. In the fuel injection device 400, the control current S9 generates a magnetic flux in the coil 402, and the magnetic flux causes the piston 410 to move in direction A along the central axis X1 (see Figure 5). Fig. 2) Based on the movement of the piston 410, the stroke amount of the piston 410 in relation to the opening cup 409 is set.

[0092] The fuel injection controller 82 detects the control current P for the fuel injection device 400 (coil 402) from the ammeter 430 at the predetermined measurement time setpoint ADC. In this embodiment, control currents that are detected at predetermined measurement time sets t1 to t6 are indicated by P1 to P6, and a control current that is to be detected at a future measurement time setpoint t7 is indicated by P7.

[0093] As it is in Fig. As shown in Figure 5, the arithmetic operations section 821 of the fuel injection controller 82 measures the control current P for the coil 402 at each of the predetermined measurement time specifications t1 to t6. Then, the arithmetic operations section 821 successively stores the control current P measured at each of the measurement time specifications t1 to t6 in a predetermined memory area of ​​the RAM 40 in the ECU 1.

[0094] For example, the section for arithmetic operations 821 reads the control current P1 for the first measurement time specification t1 (a first time) and the control current P2 for the second measurement time specification t2 (a second time) from RAM 40 and calculates a rate of change k1 between the control currents P1 and P2.

[0095] Next, the section for arithmetic measurement time specification 821 reads from RAM 40 the control current P2 for the second measurement time specification t2 (second time) and the control current P3 for the third measurement time specification t3 (third time) and calculates a rate of change k2 between the control currents P2 and P3.

[0096] In this embodiment, the arithmetic operations section 821 compares the rate of change k1 with the rate of change k2. If the rates of change k1 and k2 are equal, the arithmetic operations section 821 determines that the third measurement time specification t3 corresponds to the inflection point Pk. From the inflection point Pk onwards, the arithmetic operations section 821 uses linear extrapolation to predict future drive currents P4 to P7 (see the dashed line in Figure 821). Fig. 5).

[0097] Starting with the third measurement time t3, the arithmetic operations section 821 continuously records the drive current P for the coil 402 from the ammeter 430 for each of the measurement time specifications t4 to t7, based on the predetermined clock frequency. Simultaneously, the arithmetic operations section 821 predicts the future drive current P based on the recorded drive currents P.

[0098] The arithmetic operations section 821 calculates the time ta at which an amount of electrical power E (predicted value) calculated on the basis of a future control current Pa is to exceed a target amount of electrical power calculated on the basis of the control current S9. In the embodiment, the arithmetic operations section 821 calculates that a predicted amount of electrical power E is to exceed the target amount of electrical power at the time ta.

[0099] If the arithmetic operations section 821 determines that the time setpoint ta is less than (and not later than) the next measurement time setpoint t7, the arithmetic operations section 821 corrects the control current S9 to the next measurement time setpoint t7, reducing it by an amount corresponding to an excess amount of electrical power Eo (see a dark hatched area in Fig. 5) corresponds to an amount of electrical power calculated based on a control current P8. The control current P8 was predicted for the next measurement time t7.

[0100] Specifically, the arithmetic operations section 821 controls the drive current P8 predicted for the next measurement time t7 such that the amount of electrical power based on the drive current P8 corresponds to the amount of electrical power based on the control current S9. In this embodiment, the arithmetic operations section 821 corrects the control current S9 such that the drive current P8 predicted for the next measurement time t7 is reduced to the drive current P7.

[0101] Under this control, the amount of electrical power is corrected based on the control current P7 so that it matches the target amount of electrical control power, and the stroke amount of the piston 410 reaches the target value.

[0102] On the other hand, if the arithmetic section for arithmetic operations 821 determines that the time specification ta, at which the amount of electrical power E predicted based on the control current P is to exceed the target amount of electrical power, has already exceeded the next measurement time specification t7, the section for arithmetic operations 821 immediately stops supplying the control current S9.

[0103] With this configuration, the fuel injection controller 82 minimizes an increase in stroke amount due to the predicted amount of electrical power E becoming greater than the target amount of electrical power.

[0104] It should be noted that if the fuel injection controller 82 determines that the predicted amount of electrical power E should be greater than the target amount of electrical power, the fuel injection controller 82 adjusts the amount of the control current P8 to the next measurement time specification t7. Alternatively, instead of adjusting the amount of the control current P8, the fuel injection controller 82 can adjust the control current S9 such that the length of the high current S91 is shortened (see a dotted line in Fig. 5).

[0105] The fuel injection controller 82 can, for example, terminate the high-current S91 at a time te that is shorter than the next measurement time t7. In this configuration as well, the predicted amount of electrical power E can approach the target amount of electrical power, and the stroke of the piston 410 can thus be adjusted with high accuracy.

[0106] Here, the arithmetic operation section 821 can determine that, at the time specified at which the predicted amount of electrical power E is to exceed the target amount of electrical power, the correction of the high current S91 is not effective at the next measurement time specified (e.g., measurement time t7) to cause the predicted amount of electrical power E to approach the target amount of electrical power very closely. In this case, the arithmetic operation section 821 can correct the control current S9 such that the duration of the holding current S92 after the high current S91 is shortened (shortened by a time period td in the embodiment).

[0107] As a result, the piston 410 closes earlier by the time by which the holding current S92 is shortened, and the absolute amount of fuel injected by the fuel injection device 400 is reduced. Even if the correction of the high current S91 is not completely effective in some cases with regard to the predicted amount of electrical power E or the time specification, this configuration makes it possible to control the injected fuel quantity more appropriately and accurately by correcting the duration of the holding current S92.

[0108] It should be noted that the section for arithmetic operations 821 can correct the control current S9 so that each rate of change k1 and k2 between the corresponding control currents P to the predetermined measurement time specifications is greater than or equal to a predetermined threshold rate of change.

[0109] As previously described, the arithmetic operation section 821, taking into account the processing load of a CPU or the like, preferably uses linear extrapolation to predict each of the amounts of electrical power from the inflection point Pk. However, if the CPU has sufficient processing capability, the arithmetic operation section 821 can predict each of the amounts of electrical power using polynomial train extrapolation, polynomial approximation extrapolation, or a combination thereof. [Method for controlling the fuel injection device]

[0110] Next, a method for controlling the fuel injection device 400 by the fuel injection controller 82 is described.

[0111] Fig. Figure 6 is a flowchart of a procedure for controlling the fuel injection device 400 by the fuel injection controller 82.

[0112] As it is in Fig. As shown in Figure 6, in step S101 the fuel injection controller 82 supplies the fuel injection device 400 with the control current S9 (fuel injection pulse S9) according to the operating state of the internal combustion engine 100 in order to start the current control for the piston 410.

[0113] In step S102, the fuel injection controller 82 determines whether or not it should detect the control current P flowing through coil 402 from ammeter 430 at the next measurement time specification ADC. If the fuel injection controller 82 determines to do so at the next measurement time specification ADC (step S102: YES), it proceeds to step S103. If the fuel injection controller 82 determines not to do so at the next measurement time specification ADC (step S102: NO), it repeats the process of step S102 at each predetermined period until the next measurement time specification ADC is actually reached.

[0114] In step S103, the fuel injection controller 82 detects the control current P, which flows through the coil 402 and was measured by the ammeter 430, based on the predetermined sampling clock and the measurement time specification ADC.

[0115] In step S104, the fuel injection controller 82 stores the control current P (detected in step S103) in a storage device such as the RAM 40.

[0116] In step S105, the fuel injection controller 82 reads from RAM 40 the control currents P measured at the previous measurement time settings and the control current P measured at the current measurement time setting, both of which are stored in RAM 40 in step S104. Based on these control currents P, the fuel injection controller 82 determines whether the control current P measured at the current measurement time setting corresponds to the inflection point Pk or not. If the fuel injection controller 82 determines that the current P measured at the current measurement time setting corresponds to the inflection point Pk, the fuel injection controller 82 uses linear extrapolation to calculate each of the control currents P starting from the inflection point Pk.

[0117] In step S106, the fuel injection controller 82 calculates the amount of electrical power based on the predicted value of the control current P calculated in step S105. At the same time, the fuel injection controller 82 compares the amount of electrical power with the target amount of electrical power, which is based on the operating state of the internal combustion engine 100 and is required for the stroke of the controlled piston 410.

[0118] Based on the predicted value of the amount of electrical power and the target amount of electrical power, the fuel injection controller 82 calculates the time setpoint te (hereinafter referred to as the exceedance time setpoint te) at which the predicted amount of electrical power is to exceed the target amount of electrical power.

[0119] In step S107, the fuel injection controller 82 determines whether the overrun time target te calculated in step S106 is below (not later than) the next measurement time target ADC. If the fuel injection controller 82 determines that the overrun time target te is below (not later than) the next measurement time target ADC (step S107: YES), the fuel injection controller 82 proceeds to step S108. If the fuel injection controller 82 determines that the overrun time target te is equal to or greater than (at or later than) the next measurement time target ADC (step S107: NO), the fuel injection controller 82 returns to step S102 to detect the control current P at the next measurement time target ADC.

[0120] In step S108, the fuel injection controller 82 determines whether the overrun time target calculated in step S106 is equal to or less than the current time (at or not later than it). If the fuel injection controller 82 determines that the overrun time target has already exceeded the current time (step S108: YES), the fuel injection controller 82 proceeds to step S109 to immediately stop the supply of the control current S9 to the fuel injection device 400. In this configuration, the fuel injection controller 82 minimizes the excess fuel injection due to the large quantity of control current S9 supplied.

[0121] If, on the other hand, the fuel injection controller 82 determines that the overrun time setpoint te has not exceeded the current time (is later than the current time), the fuel injection controller 82 waits until the overrun time setpoint te exceeds the current time. The fuel injection controller 82 stops supplying the control current S9 to the fuel injection device 400 at the time setpoint at which the overrun time setpoint te exceeds the current time.

[0122] As described above, in the embodiment: (1) A fuel injection controller 82 (a fuel injection control device) for controlling a fuel injection device 400 comprises an arithmetic operations section 821 (a current prediction unit), a fundamental waveform detection section 823, and an A / D converter 824. The arithmetic operations section 821 and the fundamental waveform detection section 823 are each configured to generate a control current S9 for controlling the fuel injection device 400. The A / D converter 824 is configured to detect a drive current P for the fuel injection device 400, controlled based on the control current S9, at each of the measurement time specifications t1 to t6 (each predetermined time) based on a counter cycle.The section for arithmetic operations 821 is designed to predict, based on a control current P1 (first control current) to a first measurement time specification t1 (first time) and a control current P2 (second control current) to a second measurement time specification t2 (second time) later than the first measurement time specification t1, each of which is detected by the fundamental waveform detection section 823, a control current P3 (third control current) to a third measurement time specification t3 (third time) later than the second measurement time specification.In this configuration, the Arithmetic Operations Section 821 performs a comparison between a predicted amount of electrical power calculated based on the drive current P3 to the third measurement time specification t3, which the Arithmetic Operations Section 821 has predicted, and a target amount of electrical power calculated based on a predetermined control current (target drive current) to correct the control current S9.

[0123] In this configuration, the arithmetic operations section 821 compares an amount of electrical power calculated based on a future control current P, predicted according to previously measured control currents P, with the target amount of electrical power calculated based on the control current S9 as the target value. Based on the above comparison, the control current S9 is corrected, thus controlling the fuel injection with greater accuracy.

[0124] (2) The section for arithmetic operations 821 is also designed to calculate an exceedance time te at which a predicted amount of electrical power E is to exceed the target amount of electrical power, and to stop generating the control current S9 at the time of determining that the exceedance time te is below (not later than) the next measurement time at which the control current P is to be recorded.

[0125] If, in this configuration, the arithmetic operations section 821 determines that the predicted amount of electrical power E is to exceed the target amount of electrical power before the next measurement time, the arithmetic operations section 821 immediately stops the generation of the control current S9. Thus, the stroke of a piston 410 in the fuel injection device 400 is less prone to overshooting, and the injected fuel quantity is appropriately controlled.

[0126] (3) Section 821 for arithmetic operations is designed to use linear extrapolation to calculate the drive current P3 to the third measurement time specification later than the second measurement time specification based on at least the drive current P1 to the first measurement time specification t1 and the drive current P2 to the second measurement time specification t2.

[0127] In this configuration, the arithmetic operations section 821 uses linear extrapolation as a simple arithmetic expression to predict the future drive current P3 based on the previously measured drive currents P1 and P2. In this state, the processing load of the arithmetic operations section 821 (CPU) is reduced.

[0128] (4) The arithmetic operations section 821 is designed to identify a difference between the control current P3 at the third measurement time target t3 (which the arithmetic operations section 821 has predicted) and the control current P4 at the current time (which is being recorded at the measurement time target t4 [current predetermined measurement time]) and to correct an amount and / or length of the control current S9 based on the difference.

[0129] In this configuration, the arithmetic operations section 821 corrects the amount or length of the control current S9 based on the control current P contributing to the stroke of piston 410, thus enabling the stroke of piston 410 (the amount of fuel injected) to be controlled with high accuracy.

[0130] (5) Furthermore, the arithmetic operations section 821 is designed to correct, when the rate of change k2 of the control current at the second measurement time t2 (which the arithmetic operations section 821 has predicted) is greater than or equal to a predetermined threshold rate of change, a rate of change of the control current that is predicted at the third measurement time t3 later than the second measurement time t2.

[0131] In this configuration, the arithmetic operations section 821 predicts a rate of change of the future control current P based on the rate of change of the previously measured control current P in order to correct the control current S9, thus accurately correcting the future control current P. As a result, the arithmetic operations section 821 accurately controls the stroke of the piston 402 (the amount of fuel injected) in the fuel injection device 400 based on the precisely corrected control current P.

[0132] (6) Furthermore, a RAM 40 (a current storage unit) is provided, which stores drive currents (e.g., drive currents P1 to P6) that were acquired by the fundamental waveform acquisition section 823 at several earlier times, wherein the arithmetic operations section 821 is configured to calculate an inflection point Pk of the drive current based on the drive currents (e.g., drive currents P1 to P6) that were acquired at several earlier times and stored in the RAM 40. Simultaneously, the arithmetic operations section 821 is configured to predict the drive current P based on the inflection point Pk that the arithmetic operations section 821 has calculated.

[0133] In this configuration, the arithmetic operations section 821 easily predicts each of the control currents P from the turning point Pk and controls the stroke of the piston 410 (the amount of fuel injected) in the fuel injection device 400 with high accuracy.

[0134] An exemplary embodiment of the present invention has been described above; however, in the present invention, all of the above embodiments can be combined with one another, or two or more of the above embodiments can be preferably and arbitrarily combined.

[0135] Furthermore, the configurations described in the foregoing embodiment are merely illustrative and the present invention is not limited thereto; therefore, the configurations described in the foregoing embodiment can be partially replaced by those in other embodiments or replace them entirely.

[0136] Furthermore, the configurations described in the foregoing embodiment can be partially added to, removed from, or replaced by those in other embodiments. Reference symbol list 1 electronic control unit (ECU) 10 Analog Input Section 20 Digital Input Section 30 A / D converters 40 RAM 50 MPU 60 ROM 70 I / O connector 80 Output circuit 81 Total controllers 82 Fuel injection controller 821 Section for arithmetic operations 822 Correction section 823 Fundamental waveform acquisition section 824 A / D converter 825 D / A converter 83 Ignition controllers 84 Cylinder discrimination section 85 Angle Information Generation Section 86 Speed ​​Information Generation Section 87 Inlet air volume measuring section 88 Load Information Generation Section 89 Water temperature measuring section 100 internal combustion engine 110 air purifiers 111 Inlet pipe 112 Intake manifold 113 Throttle valve 113a Throttle opening sensor 114 Flow sensor 115 Intake air temperature sensor 120 ring gear 121 Crank angle sensor 122 Water temperature sensor 123 Crankshaft 125 Accelerator pedal 126 Accelerator pedal position sensor 130 fuel tank 131 Fuel pump 132 pressure regulators 133 Fuel line 140 cylinder pressure sensor 150 cylinders 160 exhaust manifold 161 Three-way catalyst 162 Upstream air / fuel ratio sensor 163 Downstream air / fuel ratio sensor 170 pistons 200 spark plug 300 Ignition coil 400 Fuel injection device 402 coil 430 current meters

Claims

[1] A fuel injection control device for controlling a fuel injection device, the fuel injection control device comprising: a control current generation unit configured to generate a control current for controlling the fuel injection device; a current detection unit configured to detect, at each predetermined time, a drive current for the fuel injection device controlled based on the control current; and a current prediction unit configured to predict a third drive current at a third time later than the second time based on a first drive current at a first time and a second drive current at a second time later than the first time, each of which is detected by the current detection unit, where the control current generation unit makes a comparison between a predicted amount of electric power calculated based on the third drive current predicted by the current prediction unit at the third time and a target amount of electric power calculated based on a predetermined target drive current to correct the control current. [2] Fuel injection control device according to claim 1, wherein the power prediction unit calculates an excess time at which the predicted amount of electric power should exceed the target amount of electric power, and when it is determined that the overshoot time is less than a next predetermined time at which the drive current is detected, the control current generation unit stops generating the control current. [3] The fuel injection control device according to claim 2, wherein the current prediction unit calculates the third drive current at the third time later than the second time by means of linear extrapolation based on at least the first drive current at the first time and the second drive current at the second time. [4] The fuel injection control device according to claim 3, wherein the control current generation unit corrects an amount and / or a length of the control current based on a difference between the drive electric power at the third time predicted by the current prediction unit and the current drive electric power detected at a current predetermined time. [5] The fuel injection control device according to claim 4, wherein when a change rate of the second drive current at the second time is greater than or equal to a predetermined threshold change rate, the control current generation unit corrects a change rate of the control current predicted at the third time later than the second time. [6] The fuel injection control device according to claim 5, further comprising a current storage unit configured to store drive currents detected by the current detection unit at a plurality of previous times, wherein the control current generation unit calculates an inflection point of the drive current based on the drive currents at the plurality of previous times that the current storage unit has stored, and the current prediction unit predicts the drive current based on the inflection point calculated by the control current generation unit. [7] A fuel injection control method for controlling a fuel injection device, the fuel injection control method comprising: a control current generating step for generating a control current for controlling the fuel injection device; a current detecting step for detecting a drive current at each predetermined time for the fuel injection device controlled based on the control current; and a current prediction step configured to predict a third drive current at a third time later than the second time based on a first drive current at a first time and a second drive current at a second time later than the first time, which are respectively detected in the current detection step, where the control current generation step makes a comparison between a predicted electric power calculated based on the third drive current predicted in the current prediction step at the third time and a target electric power calculated based on a predetermined target drive current to correct the control current. [8] The fuel injection control method according to claim 7, wherein the current prediction step predicts the third drive current at the third time by extrapolation based on at least the first drive current at the first time and the second drive current at the second time. [9] The fuel injection control method according to claim 8, wherein the control current generating step corrects an amount and / or a length of the control current based on a difference between the drive electric current at the third time predicted in the current predicting step and a current drive current detected at a current predetermined timing. [10] A fuel injection control method according to claim 9, further comprising a current storage step for storing drive currents detected at a plurality of previous times in the current detection step, wherein the control current generation step calculates an inflection point of the drive current based on the drive currents at the plurality of previous times stored in the current storage step, and the current prediction step predicts the drive current based on the inflection point calculated in the control current generation step.

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