Solenoid valve control device

Abstract

The present invention provides a solenoid valve control device, which can detect the movement of a valve body corresponding to a drive instruction without adding a special circuit. The solenoid valve control device of the present invention controls the opening and closing of a solenoid valve in an internal combustion engine system, wherein the internal combustion engine system includes: a fuel pump having a plunger that increases and decreases the volume of a pressurized chamber by moving up and down with the rotation of a pump drive cam, a solenoid valve for sucking fuel into the pressurized chamber, and a discharge valve for discharging the fuel from the pressurized chamber; and a fuel rail (common rail) for accumulating the fuel discharged by the fuel pump. In addition, the solenoid valve control device has a control unit, which determines whether the solenoid valve is successfully closed based on the fuel pressure (604) of the fuel rail, or calculates the discharge amount achieved by closing the solenoid valve based on the fuel pressure of the fuel rail.

Description

Technical Field

[0001] The invention relates to a solenoid valve control device. Background Art

[0002] Automobile internal combustion engines require high efficiency, low emissions, and high power. As a means to meet these requirements in a balanced manner, direct injection internal combustion engines are becoming popular. Direct injection internal combustion engines are internal combustion engines that directly inject fuel pressurized by a high-pressure fuel pump into the cylinder from the fuel injection valve. In recent years, legal regulations on the exhaust performance of internal combustion engines have been strengthened worldwide. As a countermeasure, various technologies that can improve homogeneity and reduce unburned fuel in direct injection internal combustion engines have been studied and put into practical use.

[0003] As a technology to achieve improved homogeneity, there are, for example, technologies to increase the pressure of the fuel injected into the cylinder and promote fuel atomization. In a high-pressure fuel pump, in order to achieve high pressure of the fuel, a return spring corresponding to the fluid force of the high-pressure fuel is required. However, when the return spring is strengthened, the responsiveness of the action deteriorates, so in order to meet the high fuel pressure and responsiveness, it is necessary to improve the additional mechanism and components. Then, when the high-pressure fuel pump becomes a complex structure, there is a risk of increased noise caused by driving and an increase in the number of noise occurrences.

[0004] The conventional silent control of pumps is described in, for example, Patent Document 1. Patent Document 1 discloses a control device for a high-pressure pump, which includes: a motion detection unit that detects the motion of a valve body corresponding to a drive instruction when the solenoid unit is energized according to a drive instruction of a control valve so that the valve body is displaced to a target position; and a power-on control unit that, when the motion detection unit detects that the valve body has displaced to the target position when the power was previously energized, implements power reduction control to reduce the power supplied to the solenoid unit by a predetermined amount when the power is subsequently energized compared to when the power was previously energized.

[0005] In addition, the motion detection unit in the control device of the high-pressure pump described in Patent Document 1 detects the movement of the valve body corresponding to the drive instruction by detecting at least one of the change in the current flowing through the electromagnetic part, the change in the voltage applied to the electromagnetic part, the displacement of the valve body, and the vibration of the control valve.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2017-075609 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, in order to detect changes in current flowing through the electromagnetic part and changes in voltage applied to the electromagnetic part as the control device for a high-pressure pump described in Patent Document 1 generally does, it is necessary to add special circuits such as a low-pass filter circuit and an operational amplifier circuit to the existing control circuit.

[0011] An object of the present invention is to provide a solenoid valve control device capable of detecting the movement of a valve body corresponding to a drive command without adding a special circuit in view of the above-mentioned problem.

[0012] Methods for solving problems

[0013] In order to solve the above problems and achieve the purpose of the present invention, the solenoid valve control device of the present invention controls the opening and closing of the solenoid valve in an internal combustion engine system including a plunger that moves up and down with the rotation of a camshaft to increase or decrease the volume of a pressurized chamber, a solenoid valve for sucking fuel into the pressurized chamber, a fuel pump for discharging the fuel from the pressurized chamber, and a fuel rail for accumulating the fuel discharged from the fuel pump. In addition, the solenoid valve control device includes a control unit that determines whether the solenoid valve is successfully closed based on the fuel pressure of the fuel rail, or calculates the discharge amount achieved by closing the solenoid valve based on the fuel pressure of the fuel rail.

[0014] Effects of the Invention

[0015] According to the solenoid valve control device having the above configuration, the movement of the valve body corresponding to the drive command can be detected without adding a special circuit.

[0016] In addition, the problems, structures, and effects other than those described above will be explained through the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an overall configuration diagram showing a basic configuration example of an internal combustion engine equipped with a fuel injection control device according to a first embodiment of the present invention.

[0018] Figure 2 This is a schematic configuration diagram of an ECU according to a first embodiment of the present invention.

[0019] Figure 3 It is an overall configuration diagram of a fuel system according to a first embodiment of the present invention.

[0020] Figure 4 It is a diagram showing a timing chart of the operation of the high-pressure fuel pump according to the first embodiment of the present invention.

[0021] Figure 5 It is a graph showing the variation in individual characteristics of the high-pressure fuel pump.

[0022] Figure 6 This is a graph showing the relationship between the driving current value of the high-pressure fuel pump and the noise level.

[0023] Figure 7 This is a diagram showing the relationship between fuel discharge from a high-pressure fuel pump, fuel injection from a fuel injection valve, and fuel pressure in a common rail.

[0024] Figure 8 This is a flowchart of the solenoid valve control in the high-pressure fuel pump according to the first embodiment of the present invention.

[0025] Fig. 9 This is a diagram showing an example of filtering used for fuel pressure data according to the first embodiment of the present invention.

[0026] Fig.10 This is a diagram showing the relationship among fuel discharge from a high-pressure fuel pump, fuel injection from a fuel injection valve, fuel pressure in a common rail, and fuel pressure after filtering according to the first embodiment of the present invention.

[0027] Fig.11 This is a flowchart of the solenoid valve control in the high-pressure fuel pump according to the second embodiment of the present invention.

[0028] Fig.12 This is a flowchart of the solenoid valve control in the high-pressure fuel pump according to the third embodiment of the present invention.

[0029] Fig.13 This is a diagram showing the relationship among fuel discharge from a high-pressure fuel pump, fuel injection from a fuel injection valve, fuel pressure in a common rail, and fuel pressure after filtering according to a third embodiment of the present invention.

[0030] Fig.14 This is a flowchart of fuel injection valve control according to the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0031] 1. First Implementation Method

[0032] Hereinafter, a solenoid valve control device according to a first embodiment of the present invention will be described. In addition, in each figure, the same reference numerals are attached to common components.

[0033] [Internal combustion engine system]

[0034] First, the configuration of an internal combustion engine system equipped with a solenoid valve control device according to the present embodiment will be described. Figure 1 It is an overall configuration diagram of an internal combustion engine system equipped with a fuel injection control device according to an embodiment.

[0035] Figure 1The internal combustion engine (engine) 101 shown is a 4-stroke engine that repeatedly performs the four strokes of intake stroke, compression stroke, combustion (expansion) stroke, and exhaust stroke, and is, for example, a multi-cylinder engine having four cylinders (cylinders). In addition, the number of cylinders of the internal combustion engine 101 is not limited to 4, and may also have 3, 6, or 8 or more cylinders.

[0036] The internal combustion engine 101 includes a piston 102, an intake valve 103, and an exhaust valve 104. The intake air (intake air) of the internal combustion engine 101 passes through an air flow meter (AFM) 120 that detects the amount of air flowing in, and the flow rate is adjusted by a throttle valve 119. The air after passing through the throttle valve 119 is sucked into a branching portion, i.e., an air collecting chamber 115, and then is supplied to a combustion chamber 121 of each cylinder via an intake pipe 110 and an intake valve 103 provided for each cylinder (cylinder).

[0037] On the other hand, the fuel is supplied from the fuel tank 123 to the plurality of high-pressure fuel pumps 125 by the low-pressure fuel pump 124, and the fuel is increased to a pressure required for fuel injection by each high-pressure fuel pump 125. That is, the high-pressure fuel pump 125 uses the power transmitted from the exhaust cam shaft (not shown) of the exhaust cam 128 to cause the plunger (hereinafter referred to as Figure 3 The fuel pump 124 moves up and down (to be described) to pressurize (increase the pressure) the fuel in the high-pressure fuel pump 125.

[0038] An on-off valve (a solenoid suction valve 300 described later) driven by a solenoid is provided at the suction port of the high-pressure fuel pump 125. The solenoid is connected to an ECU (Engine Control Unit) 109. The ECU 109 includes a solenoid valve control device that controls the driving of the solenoid valve. The ECU 109 controls the solenoid to drive the on-off valve so that the pressure of the fuel (fuel pressure) discharged from the high-pressure fuel pump 125 becomes the required pressure.

[0039] The fuel pressurized by the high-pressure fuel pump 125 is delivered to the fuel injection valve 105 via the common rail 129. The common rail 129 is provided in plurality corresponding to the plurality of high-pressure fuel pumps 125, and accumulates the pressure of the fuel discharged from the high-pressure fuel pump 125, respectively.

[0040] The fuel injection valve 105 is a direct injection type that can perform fuel injection into the combustion chamber 121 multiple times in one cycle. The fuel injection valve 105 operates the valve body to perform fuel injection by, for example, supplying a driving current (energizing) to the electromagnetic coil (solenoid). The fuel injection valve 105 receives a command (injection pulse) from the ECU 109, and opens the valve for a time specified by the command, thereby injecting fuel into the combustion chamber 121.

[0041] Furthermore, the total amount of fuel injected from the fuel injection valve 105 in one cycle (total fuel injection amount) can be determined in advance, and each value of the fuel injection amount of a plurality of fuel injections (injection amounts for each time) can also be determined in advance.

[0042] In addition, the internal combustion engine 101 is provided with a fuel pressure sensor (fuel pressure sensor) 126 for measuring the fuel pressure in the common rail 129. The fuel pressure measured by the fuel pressure sensor 126 is the actual fuel pressure supplied to the fuel injection valve 105, that is, the actual fuel pressure. Based on the measurement result obtained by the fuel pressure sensor 126, the ECU 109 sends a control command to the fuel injection valve 105 for making the fuel pressure in the common rail 129 become the required pressure. That is, the ECU 109 performs so-called feedback control to make the fuel pressure in the common rail 129 become the required pressure.

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

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

[0045] The exhaust gas generated by the combustion is discharged to the exhaust pipe 111 through the exhaust valve 104. Then, a three-way catalyst 112 and an oxygen sensor 113 are provided in the exhaust pipe 111. The three-way catalyst 112 purifies harmful substances such as nitrogen oxides (NOx) contained in the exhaust gas. The oxygen sensor 113 detects the oxygen concentration contained in the exhaust gas and outputs the detection result to the ECU 109. Based on the detection result of the oxygen sensor 113, the ECU 109 performs feedback control in such a way that the fuel injection amount supplied from the fuel injection valve 105 becomes the target air-fuel ratio.

[0046] In addition, the piston 102 is connected to a crankshaft 131 via a connecting rod 132. Then, the reciprocating motion of the piston 102 is converted into a rotational motion by the crankshaft 131. Then, a crank angle sensor 116 is installed on the crankshaft 131. The crank angle sensor 116 detects the rotation and phase of the crankshaft 131 and outputs the detection result to the ECU 109. The ECU 109 can detect the rotation speed of the internal combustion engine 101 based on the output of the crank angle sensor 116.

[0047] Signals from a crank angle sensor 116 , an air flow meter 120 , an oxygen sensor 113 , an accelerator opening sensor 122 indicating an opening of an accelerator operated by a driver, a fuel pressure sensor 126 , and the like are input to the ECU 109 .

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

[0049] ECU109 uses the outputs of various sensors to calculate the amount of fuel and the number of injections corresponding to the amount of intake air in each cylinder (combustion chamber 121). Then, ECU109 outputs a fuel injection signal corresponding to the calculated amount of fuel and the number of injections to the fuel injection valve 105. Furthermore, ECU109 outputs an energization signal to the ignition coil 107 and an ignition signal to the spark plug 106.

[0050] The internal combustion engine 101 is mainly required to have low fuel consumption, high power, and exhaust gas purification, but also to reduce noise and vibration as a greater added value. Then, in the high-pressure fuel pump 125, when the electromagnetic intake valve is opened and closed, the valve body and the armature collide with the stopper, generating noise.

[0051] [ECU structure]

[0052] Next, for Figure 1 The structure of ECU109 shown in the figure uses Figure 2 Provide explanation.

[0053] Figure 2 This is a schematic structural diagram of ECU109.

[0054] The ECU 109 includes an input circuit 203, an A / D converter 204, a central processing unit (CPU) 205, and an output circuit 210. The CPU 205 implements a plurality of functions described below by executing a program stored in advance.

[0055] In addition, the ECU may include a rewritable logic circuit, namely, an FPGA (Field Programmable Gate Array), or an integrated circuit for a specific application, namely, an ASIC (Application Specific Integrated Circuit).

[0056] The input circuit 203 imports the signal output from the sensors 201 (oxygen sensor 113, crank angle sensor 116, air flow meter 120, accelerator opening sensor 122, etc.) as the input signal 202. When the input signal 202 is an analog signal, the input circuit 203 removes noise components from the input signal 202, and outputs the signal after the noise is removed to the A / D conversion unit 204.

[0057] The A / D converter 204 converts the analog signal into a digital signal and outputs it to the CPU 205. The CPU 205 receives the digital signal output from the A / D converter 204 and executes a control logic (program) stored in advance, thereby performing various calculations, diagnosis, control, and the like.

[0058] The calculation result of the CPU 205 is outputted from the output circuit 210 as a control signal 211, and the actuators 212 provided in the intake valve 103, the exhaust valve 104, the fuel injection valve 105, and the plurality of high-pressure fuel pumps 125 are driven. On the other hand, when the input signal 202 is a digital signal, it is directly sent from the input circuit 203 to the CPU 205 via the signal line 206, and the CPU 205 performs necessary calculations, diagnosis, control, etc.

[0059] In addition, the CPU 205 and the A / D conversion unit 204 constitute a microcomputer (hereinafter referred to as "microcomputer") 220. The microcomputer 220 is a specific example of the control unit of the present invention, and performs filtering processing, electromagnetic valve diagnosis processing, etc., which will be described later. The filtering processing and electromagnetic valve diagnosis processing can be executed using hardware resources of the microcomputer 220, or can be executed using software.

[0060] [Structure of high-pressure fuel pump]

[0061] Next, regarding the structure of the fuel system of this embodiment, use Figure 3 Provide explanation.

[0062] Figure 3 It is an overall configuration diagram of the fuel system of this embodiment.

[0063] like Figure 3 As shown, the high-pressure fuel pump 125 pressurizes the fuel supplied from the fuel tank 123 and sends it to the common rail 129. The fuel is supplied from the fuel tank 123 to the low-pressure fuel pump 124, and is guided from the low-pressure fuel pump 124 to the fuel inlet of the high-pressure fuel pump 125. At this time, the fuel is regulated to a constant pressure by the pressure regulator 152.

[0064] The high-pressure fuel pump 125 has a housing 323. The housing 323 is provided with a communication port 321, an outflow port 322, an inflow port 325, and a pressurizing chamber 311. The high-pressure fuel pump 125 also has a plunger 302 that moves up and down due to the rotation of a pump drive cam 301 mounted on a camshaft of the internal combustion engine 101, an electromagnetic suction valve 300 that opens and closes in synchronization with the up and down movement of the plunger 302, and a discharge valve 310 that discharges fuel to the common rail 129.

[0065] When the plunger 302 descends, the volume of the pressurized chamber 311 expands, and when the plunger 302 ascends, the volume of the pressurized chamber 311 decreases. That is, the plunger 302 is configured to reciprocate in the direction of expanding and reducing the volume of the pressurized chamber 311. The discharge valve 310 opens and closes the outflow port 322. The spring portion 326 applies force to the discharge valve 310 in the valve opening direction. That is, the discharge valve 310 is always applied in the direction of closing the outflow port 322. When the pressure of the fuel in the pressurized chamber 311 is greater than the force of the spring portion 326, the outflow port 322 opens. As a result, the fuel in the pressurized chamber 311 is discharged to the common rail 129.

[0066] The electromagnetic suction valve 300 is a normally open electromagnetic valve, and a force acts in the valve opening direction when no power is supplied, and a force acts in the valve closing direction when power is supplied. The electromagnetic suction valve 300 includes a valve body 303, a first spring 309 for applying a force to the valve body 303 in the valve opening direction, a second spring 315 for applying a force to the valve body 303 in the valve closing direction, a solenoid 305, and an armature 304.

[0067] The valve body 303 is formed in a substantially rod-like shape, and an armature 304 is provided at one end in the axial direction. In addition, an abutment piece 303a is formed at the other end of the valve body 303. The abutment piece 303a abuts against a seat portion 307 provided at the inlet 325 when the valve is closed. Thus, the valve body 303 closes the communicating portion between the inlet 325 and the pressurizing chamber 311.

[0068] One end of the first spring 309 is connected to the armature 304. The other end of the first spring 309 is connected to the housing 323. One end of the second spring 315 is connected to the stopper 308 disposed between the valve body 303 and the pressurizing chamber 311. The other end of the second spring 315 is connected to the end of the valve body 303 on the opposite side to the armature 304.

[0069] The solenoid 305 is opposite to the armature 304. When current flows through the solenoid 305, an electromagnetic force is generated between the solenoid 305 and the armature 304. As a result, the armature 304 is attracted in a direction that resists the spring force of the first spring 309 ( Figure 3 The left side in the figure) is the valve closing direction.

[0070] In the high-pressure fuel pump 125, the axial direction ( Figure 3 When the solenoid 305 is energized to the OFF state, the armature 304 is always moved in the valve opening direction ( Figure 3 Thus, the valve body 303 is maintained in the valve open position.

[0071] When the solenoid 305 is energized, an electromagnetic attraction force is generated between the fixed portion 306 (magnetic core) and the armature 304. As a result, the armature 304 is attracted in the valve closing direction ( Figure 3 When the armature 304 is attracted to the fixed portion 306, the valve body 303 becomes a check valve that opens and closes based on the pressure difference between the upstream side and the downstream side and the force of the second spring 315.

[0072] When the pressure on the downstream side of the valve body 303 rises, the valve body 303 moves in the valve closing direction. When the valve body 303 moves in the valve closing direction by a set lift amount, it sits on the seat portion 307. As a result, the electromagnetic suction valve 300 becomes a closed valve state, and the fuel in the pressurizing chamber 311 cannot flow back to the low-pressure piping side.

[0073] When the plunger 302 descends, when the electromagnetic suction valve 300 opens, fuel flows into the pressurizing chamber 311 from the inlet 325. Hereinafter, the stroke of the plunger 2 descending is referred to as the suction stroke. On the other hand, when the plunger 302 ascends, when the electromagnetic suction valve 300 closes, the fuel in the pressurizing chamber 311 is pressurized and sent to the common rail 129 through the discharge valve 310 (outlet 322). Hereinafter, the stroke of the plunger 302 ascending is referred to as the compression stroke.

[0074] If the electromagnetic suction valve 300 is closed during the compression stroke, the fuel sucked into the pressurizing chamber 311 during the suction stroke is pressurized and discharged to the common rail 129. On the other hand, if the electromagnetic suction valve 300 is opened during the compression stroke, the fuel in the pressurizing chamber 311 is pushed back to the inlet 325 and is not discharged to the common rail 129. In this way, the high-pressure fuel pump 125 discharges the fuel by the opening and closing operation of the electromagnetic suction valve 300. Then, the opening and closing of the electromagnetic suction valve 300 is controlled by the ECU 109 (solenoid valve control device).

[0075] The common rail 129 accumulates the pressure of the fuel discharged from the high-pressure fuel pump 125. A plurality of fuel injection valves 105, a fuel pressure sensor 126, and a pressure regulating valve (hereinafter referred to as a "pressure reducing valve") 355 are installed on the common rail 129. The pressure reducing valve 355 opens when the fuel pressure in the common rail 129 exceeds a specified value to prevent damage to the piping. The plurality of fuel injection valves 105 are installed in accordance with the number of cylinders (combustion chambers 121), and the fuel is injected according to the drive current output from the ECU 109.

[0076] The fuel pressure sensor 126 outputs the detected pressure data to the ECU 109. The ECU 109 calculates the appropriate injection fuel amount (target injection fuel amount) and the appropriate fuel pressure (target fuel pressure) based on the engine state quantities (e.g., crankshaft rotation angle, throttle opening, engine speed, fuel pressure, etc.) obtained from various sensors.

[0077] In addition, ECU109 controls the driving of high-pressure fuel pump 125 and multiple fuel injection valves 105 based on the calculation results. That is, ECU109 (solenoid valve control device) has a pump control unit that controls high-pressure fuel pump 125 and an injection valve control unit that controls fuel injection valves 105.

[0078] [Operation of the high-pressure fuel pump]

[0079] Next, the operation of the high pressure fuel pump of this embodiment is described using Figure 4 Provide explanation.

[0080] Figure 4 It is a timing chart for explaining the operation of the high-pressure fuel pump 125 .

[0081] The electromagnetic suction valve 300 opens and closes in synchronization with the rise and fall of the plunger 302. The ECU 109 (electromagnetic valve control device) detects the rotation angle of the pump drive cam 301, and starts applying a voltage V to both ends of the solenoid 305 (time t1) after the pump drive cam 301 rotates from the top dead center (TDC: Top Dead Center) to a determined angle (P_ON time).

[0082] The current I flowing through the solenoid 305 increases according to the equation 1. Wherein, L is the inductance of the solenoid 305 and the wiring, and R is the resistance of the solenoid 305 and the wiring.

[0083] LdI / dt=V-RI…(Formula 1)

[0084] As the current I increases, the magnetic attraction force Fmag of the fixed part 306 (magnetic core) attracting the armature 304 increases. When the magnetic attraction force Fmag is greater than the spring force Fsp of the first spring 309, the armature 304 pressed by the spring force Fsp starts to move toward the fixed part 306 (time t2).

[0085] When the armature 304 moves toward the fixed portion 306, the valve body 303, which is pushed by the fuel pressurized by the rise of the plunger 302, moves toward the fixed portion 306 following the armature 304. Then, the contact piece 303a of the valve body 303 collides with the seat 307. That is, the valve body 303 sits on the seat 307. As a result, the flow path ( Figure 3 The dotted line in the pressure chamber 311 is closed, and the fuel pressurized by the rise of the plunger 302 cannot return to the low-pressure pipe side. As a result, the fuel pressure in the pressure chamber 311 rises (time t4).

[0086] When the fuel pressure in the pressurizing chamber 311 is greater than the spring force Fsp_out urging the discharge valve 310, the discharge valve 310 opens. As a result, the fuel pressurized by the rise of the plunger 302 is discharged to the common rail 129. Thereafter, when the drive pulse turns off at time t5, a reverse voltage is applied to the solenoid 305. As a result, the holding current previously supplied to the solenoid 305 is cut off.

[0087] When the cam angle passes the top dead center and the plunger 302 starts to descend (time t6), the fuel pressure in the pressurizing chamber 311 decreases. Then, when the fuel pressure in the pressurizing chamber 311 becomes smaller than the spring force Fsp_out, the discharge valve 310 closes. Thus, the high-pressure fuel pump 125 finishes discharging fuel. In addition, due to the decrease in the fuel pressure in the pressurizing chamber 311, the armature 304 moves from the closed valve position to the open valve position together with the valve body 303 (time t7 to t8).

[0088] By such an action, the high pressure fuel pump 125 delivers fuel from the low pressure pipe to the common rail 129. In this process, the armature 304 collides with the fixing portion 306 and the valve closing is completed ( Figure 4 When the armature 304 and the valve body 303 collide with the stopper 308 and the valve is opened ( Figure 4 The noise is generated at the time t8). This noise may make the driver feel uncomfortable, especially at idle speed. In this embodiment, the noise when the valve closing is completed is reduced.

[0089] [Peak current and holding current]

[0090] Next, for the peak current and holding current of this embodiment, use Figure 4 Provide explanation.

[0091] The current driving the high-pressure fuel pump 125 is roughly divided into two types. That is, the driving current of the high-pressure fuel pump 125 is divided into peak current ( Figure 4 The shaded portion of the current waveform) and the holding current ( Figure 4 The horizontal line part of the current waveform). Figure 4 As shown, the maximum current value of the peak current is assumed to be Im, and the maximum current value of the holding current is assumed to be Ik.

[0092] When the peak current flows, the valve body 303 and the armature 304, which are stationary in the valve opening position due to the force of the first spring 309, are given a tendency to close the valve. On the other hand, when the holding current flows, the armature 304, which has approached the fixed portion 306, is attracted until it collides with the fixed portion 306. Furthermore, after the armature 304 collides with the fixed portion 306, the contact state is maintained.

[0093] If the applied amount of the peak current is reduced, the tendency of the valve to close is weakened, so the noise can be reduced. However, if the applied amount of the peak current is reduced too much, the electromagnetic suction valve 300 will fail to close. Therefore, the applied amount of the peak current should be reduced as much as possible within the range of the electromagnetic suction valve 300 closing the valve.

[0094] Basically, the application amount of the peak current at the limit (minimum) of closing the electromagnetic suction valve depends on the individual characteristics of the high-pressure fuel pump. Figure 5 It is a graph showing the variation in individual characteristics of the high-pressure fuel pump. Figure 5 For the standard spring force Fsp, the upper limit spring force Fsp caused by manufacturing deviation, and the lower limit spring force Fsp caused by manufacturing deviation, the relationship between the average speed v_ave when closing the valve (the average value from the start of valve closing to the completion of valve closing) and the peak current integral value II is shown.

[0095] In the present embodiment, the peak current application amount is set as the integrated value of the current, but the same individual characteristics can be achieved even if the peak current application amount is replaced by the integrated value of the square of the current or the integrated value of the product of the current and the voltage.

[0096] according to Figure 5 , it can be seen that the relationship between the peak current integral value II and the average speed v_ave has an error due to the spring force Fsp. That is, when the average speed required in a certain solenoid valve is represented by a dotted line, the required peak current integral value II has a large error in the range of A to C due to individual differences.

[0097] When the valve closing limit current corresponding to the lower limit of the spring force Fsp is set to the upper limit of the spring force Fsp, the magnetic attraction force generated by the solenoid is smaller than the spring force, and the electromagnetic suction valve will fail to close. Therefore, the valve closing limit current needs to be selected to correspond to the upper limit of the spring force Fsp. However, when the lower limit of the spring force Fsp is controlled according to the valve closing limit current corresponding to the upper limit of the spring force Fsp, a magnetic attraction force that is excessive compared to the spring force is generated. As a result, the electromagnetic suction valve will close at a speed higher than necessary.

[0098] Figure 6 is a graph showing the relationship between the driving current value and the noise level of the high-pressure fuel pump. Figure 6 As shown in FIG. 1 , as the peak current integral value II increases, the noise level also increases. Figure 5 As explained above, the value of the valve closing limit current needs to be set to a value (current value C) corresponding to the upper limit of the spring force Fsp. However, the current value required for the lower limit of the spring force Fsp is current value A. Therefore, Figure 5 The width of the two arrows shown is the deviation of the noise level. That is, if the current value applied to the lower limit product of the spring force Fsp can be reduced to the current value A which is the originally required value, the noise level corresponding to the deviation can be reduced.

[0099] [Use fuel rail pressure to detect valve closure]

[0100] In order to apply a current value corresponding to the spring force Fsp, in other words, an appropriate current value corresponding to the individual difference of the pump, to the solenoid valve, it is necessary to detect the individual difference of the pump. In this embodiment, the fuel rail pressure (fuel pressure in the common rail 129) is used as a means for detecting the individual difference.

[0101] The high-pressure fuel pump 125 and the fuel injection valve 105 are connected to the common rail 129 having a pressure accumulation function. The operation of each electromagnetic valve in the high-pressure fuel pump 125 and the fuel injection valve 105 is closely related to the fuel pressure in the common rail 129. For example, when the electromagnetic suction valve 300 of the high-pressure fuel pump 125 is closed, the fuel pressure in the pressurizing chamber 311 increases. As a result, the fuel in the pressurizing chamber 311 is discharged from the discharge valve 310, and the fuel pressure in the common rail 129 increases. That is, the electromagnetic suction valve 300 is closed successfully, which can be considered as the fuel pressure in the common rail 129 increasing.

[0102] On the other hand, when the electromagnetic valve of the fuel injection valve 105 is closed, the fuel pressure in the common rail 129 decreases because the fuel is injected from the injection port of the fuel injection valve 105. That is, the electromagnetic valve of the fuel injection valve 105 is closed successfully, and it can be considered that the fuel pressure in the common rail 129 decreases.

[0103] Figure 7 1 is a diagram showing the relationship between the fuel discharge of the high-pressure fuel pump, the fuel injection of the fuel injection valve, and the fuel pressure of the common rail. In the high-pressure fuel pump 125, from the time when the electromagnetic suction valve 300 is closed to the time when TDC is reached, the fuel is discharged through the discharge valve 310 (fuel discharge 602 of the high-pressure pump) in accordance with the decrease in the volume of the pressurizing chamber 311 caused by the rise of the plunger 302 (increase in the cam lift 601).

[0104] The fuel injection valve 105 injects fuel (fuel injection 603 by the fuel injection valve) based on the injection instruction from the ECU 109. As a result, the fuel pressure 604 in the common rail 129 changes substantially in four sections, namely, sections A, B, C, and D.

[0105] The section A is the influence section of the fuel injection valve 105, and the fuel pressure 604 in the common rail 129 is reduced according to the fuel injection amount of the fuel injection valve 105. The next section B of the section A is a section for maintaining the fuel pressure 604 in the common rail 129. In the section B, the fuel discharge of the high-pressure fuel pump 125 and the fuel injection of the fuel injection valve 105 are not performed. Therefore, the fuel pressure 604 in the common rail 129 is maintained at the value reduced in the section A.

[0106] The next section C of the section B is the influence section of the high-pressure fuel pump 125, and the fuel pressure 604 in the common rail 129 increases according to the fuel discharge amount of the high-pressure fuel pump 125. The next section D of the section C is a section in which the fuel pressure in the common rail 129 is maintained. In this section, as in the section B, the fuel discharge of the high-pressure fuel pump 125 and the fuel injection of the fuel injection valve 105 are not performed. Therefore, the fuel pressure 604 in the common rail 129 maintains the value increased in the section C. Basically, because the injection amount of the fuel injection valve 105 is balanced with the discharge amount of the high-pressure fuel pump 125, the target fuel pressure of the system is achieved at the average fuel pressure.

[0107] According to the relationship between the pump discharge, the fuel injection valve injection, and the rail fuel pressure as described above, it can be known that by detecting the fuel pressure in the common rail 129, the valve operation of the electromagnetic suction valve 300 of the high-pressure fuel pump 125 and the fuel injection valve 105 can be known. Specifically, by detecting the fuel pressure in the common rail 129, it is possible to detect whether the electromagnetic suction valve 300 and the fuel injection valve 105 are closed. In addition, the fuel pressure in the common rail 129 can be easily detected based on the value of the fuel pressure sensor installed in the general direct injection system.

[0108] Thus, the monitoring value required in the present invention is only the value of the fuel pressure in the common rail 129 which can be read from the existing fuel pressure sensor 126. Therefore, in the present invention, there is no need to develop a new circuit or control, and compared with the existing case of developing a new circuit or control, it is possible to achieve a shorter delivery period and lower costs. On the other hand, the prior art directly detects the current and voltage values ​​in order to detect whether the solenoid valve is closed. As a result, the cost and lead time increase.

[0109] [Control of electromagnetic suction valve]

[0110] Next, for the control process of the electromagnetic suction valve 300, refer to Figure 8 Provide explanation.

[0111] Figure 8 This is a flowchart of the solenoid valve control in the high-pressure fuel pump according to the first embodiment.

[0112] First, the ECU 109 (solenoid valve control device) obtains the fuel pressure data in the common rail 129 (S101). In this process, the fuel pressure data is obtained from the fuel pressure sensor 126. In addition, the sampling period is preferably finer. However, even if the resolution level set by the prior art is 1ms, 2ms, 4ms, etc., as long as it is in the low speed to medium speed range where noise is generally a problem in the engine, it is possible to ensure sufficient accuracy for this control.

[0113] Next, the ECU 109 (solenoid valve control device) performs filtering processing according to the purpose of use on the acquired fuel pressure data ( S102 ). Fig. 9 Filter1 is calculated using Filter coefficient 801. Filter2 is calculated using Filter coefficient 802. Filter3 is calculated using Filter coefficient 803. That is, Filter1, Filter2, and Filter3 are calculated using the following equations (2) to (4), respectively.

[0114] Filter1=(1×Pf(t))+(-1×Pf(t-1))……(Formula 2)

[0115] Filter2 = (1×Pf(t))+(0×Pf(t-1))+(-1×Pf(t-2))……(Formula 3)

[0116] Filter3 = (1×Pf(t))+(0.5×Pf(t-1))+(-0.5×Pf(t-2))+(-1×Pf(t-3))……(Formula 4)

[0117] Filter1 to Filter3 are filters that cut off the DC component and extract the difference. Filter1 is the sampling period, Filter2 is twice the sampling period, and Filter3 is three times the sampling period. It is the peak of the changing gain. Therefore, the filter is preferably set to a balanced point from the perspective of detectability and noise removal compared to the sampling frequency.

[0118] Next, ECU109 (solenoid valve control device) compares the pressure data (fuel pressure 901) after filtering with the pre-set threshold value 902 to determine whether the electromagnetic intake valve 300 is successfully closed (S103). The process of S103 corresponds to the electromagnetic valve diagnosis process of the present invention. In this process, if the fuel pressure data after filtering exceeds the threshold value, it is determined that the valve is closed successfully. In addition, if the fuel pressure data after filtering is below the threshold value, it is determined that the valve is closed unsuccessfully.

[0119] Fig.101 is a diagram showing the relationship between the fuel discharge of the high-pressure fuel pump, the fuel injection of the fuel injection valve, the fuel pressure of the common rail, and the fuel pressure after filtering according to the first embodiment of the present invention. Fig.10 As shown in FIG. 1 , when the fuel pressure 901 after filtering exceeds the threshold value 902, it is considered that the fuel discharge amount has reached the target discharge amount. Therefore, it can be determined that the fuel in the pressurizing chamber 311 of the high-pressure fuel pump 125 has not returned to the inlet 325 (refer to FIG. 1 ). Figure 3 ), the valve is closed successfully.

[0120] On the other hand, when the fuel pressure 901 after filtering is below the threshold value 902, it is considered that the fuel discharge amount has not reached the target discharge amount. Therefore, it can be determined that the fuel in the pressurizing chamber 311 of the high-pressure fuel pump 125 has returned to the inlet 325 (refer to Figure 3 ), valve closing failed.

[0121] Regarding the threshold value 902, a value that does not cause false detection due to noise and detection accuracy is considered as the lower limit side. In addition, regarding the threshold value 902, a value that can be reliably detected even at the gain lower limit when the pump is discharged, including errors, is considered as the upper limit side. Then, the threshold value 902 is set between the lower limit side and the upper limit side. If only the closing of the electromagnetic suction valve 300 is detected, there is no problem with the above-mentioned consideration of the lower limit side.

[0122] However, in the scenario where the discharge volume requires accuracy, the electromagnetic suction valve 300 is closed but the responsiveness becomes slow, so the accuracy of the discharge flow rate is considered to be a problem. Therefore, when setting the lower limit side of the threshold, in addition to preventing false detection due to noise and detection accuracy, it is also necessary to consider the minimum required discharge flow rate. In addition, the threshold 902 can be set to a fixed value, but when there is more than one control scenario, it is necessary to set it with MAP according to the fuel pressure, the discharge volume of the pump, etc., or to set it variably.

[0123] The conversion from discharge flow rate to pressure change can be calculated based on pressure, volume, fuel properties, etc. using the formula for compressible fluid. Conversely, the discharge flow rate of the high-pressure fuel pump can also be calculated based on the change in the measurement signal (pressure data after differential filtering). In the process of S103, the discharge flow rate of the high-pressure fuel pump can be calculated, and based on the calculated discharge flow rate, it is determined whether to correct the current setting value to a lower value or a higher value. For example, when the calculated discharge flow rate of the high-pressure fuel pump is greater than a predetermined specified value, it is determined to be the same as the case where the valve closing is successful (determined as YES). On the other hand, when the calculated discharge flow rate of the high-pressure fuel pump is below the specified value, it is determined to be the same as the case where the valve closing fails (determined as NO).

[0124] In addition, if Fig.10 As shown, the determination window 903 is set for each cam cycle, and can reliably cover the range of actual fuel discharge within the range from the bottom dead center to the top dead center of the plunger 302, in which the high-pressure fuel pump 125 can discharge fuel. In addition, by limiting the determination window 903 to a necessary range, the risk of false detection caused by noise, etc. can be reduced.

[0125] In S103, when it is determined that the valve closing is successful (YES in S103), ECU109 (solenoid valve control device) determines that the current current setting value is excessive. Then, ECU109 (solenoid valve control device) corrects the current setting value to a value lower than the current setting value (S104). After that, ECU109 (solenoid valve control device) obtains fuel pressure data again. That is, ECU109 (solenoid valve control device) returns the process to S101.

[0126] The finer the correction amount (feedback amount) of the current setting value in S104, the higher the accuracy. However, the finer the correction amount of the current setting value, the more susceptible it is to noise, and the determination takes time. Therefore, the correction amount (feedback amount) of the current setting value in S104 can be set based on both the time allocated to this control and the required accuracy.

[0127] On the other hand, in S103, when it is determined that the valve closing fails (determined as NO in S103), ECU109 (solenoid valve control device) determines that the current current setting value is low. Then, ECU109 (solenoid valve control device) corrects the current setting value to a value higher than the current setting value (S105). After that, ECU109 (solenoid valve control device) determines that the current setting value corrected in the process of S105 is the necessary minimum current value and ends the control.

[0128] The correction amount (feedback amount) of the current setting value in S105 can be set to the current setting value at which the valve is closed successfully at the last time. However, the correction amount (feedback amount) of the current setting value in S105 is preferably set with an appropriate safety factor in consideration based on robustness. In addition, the correction amount (feedback amount) of the current setting value in S104 and S105 is stored in the storage unit as a mapping value according to the operation scene, or is variably set.

[0129] The control of the solenoid valve is to filter the pressure change for each shot (each power pulse of the solenoid valve) to determine whether the solenoid valve is successfully closed. Therefore, compared with the method of simply determining whether the solenoid valve is successfully closed based on whether the fuel pressure is reduced or increased, it is possible to detect whether the solenoid valve is successfully closed with high accuracy and directly.

[0130] In addition, by providing feedback on the driving current value to indicate whether the solenoid valve has been successfully closed, the solenoid valve can be driven with the minimum current value, which can achieve significant silencing and power saving. Furthermore, since only the fuel rail fuel pressure value (fuel pressure data in the common rail 129) as an existing monitoring value is used in the solenoid valve closing detection, there is no need to add a new control circuit, and the solenoid valve closing can be detected with the existing circuit. As a result, the development period can be greatly shortened, and a significant cost reduction can be achieved.

[0131] 2. Second Implementation Method

[0132] Next, the solenoid valve control device of the second embodiment of the present invention is described. Among them, the solenoid valve control device of the second embodiment of the present invention has the same structure as the solenoid valve control device of the first embodiment described above. The difference between the solenoid valve control device of the second embodiment and the solenoid valve control device of the first embodiment lies in the control of the solenoid suction valve. Therefore, the control of the solenoid suction valve of the second embodiment is described here, and the description of the common structures such as the ECU (solenoid valve control device), the high-pressure fuel pump, and the solenoid suction valve is omitted.

[0133] [Control of electromagnetic suction valve]

[0134] For the control process of the electromagnetic suction valve 300 according to the second embodiment, refer to Fig.11 Provide explanation.

[0135] Fig.11 This is a flowchart of the solenoid valve control according to the second embodiment.

[0136] First, ECU109 (solenoid valve control device) performs scene determination (S201). In this process, it is determined whether to continue the feedback control (processing of whether the electromagnetic intake valve is successfully closed by feeding back the driving current value) according to the operation scene. This feedback control is difficult to perform in all driving scenes. For example, during transient operation, the required fuel pressure and required discharge volume are constantly changing, and external interference is relatively large. Therefore, during transient operation, there is a possibility that appropriate feedback cannot be performed, so it is preferred not to perform this feedback control.

[0137] Specifically, as scenarios for performing this feedback control, engine factory testing, maintenance, no-load operation, or steady-state operation can be cited. When this feedback control is performed during engine factory testing, the solenoid valve can be initially silenced (before it is delivered to the user). When this feedback control is performed during maintenance, it is possible to assume that the necessary current value changes due to the durability degradation of the pump, and the current value can be adjusted again. When this feedback control is performed during no-load operation (idling operation) or steady-state operation, the noise during idling operation can be reduced. In addition, the current value can be fed back online.

[0138] In S201, when it is determined that it is not a scenario for performing the feedback control (determined as NO in S201), ECU109 (solenoid valve control device) ends the control. Thus, the feedback control is not implemented. On the other hand, in S201, when it is determined that it is a scenario for performing the feedback control (determined as YES in S201), ECU109 (solenoid valve control device) performs the processing of S202 to S206. The processing of S202 to S206 is the same as the processing of S101 to S105 of the solenoid valve control of the first embodiment. Therefore, the description of the processing of S202 to S206 is omitted here.

[0139] In the solenoid valve control of the second embodiment, the pressure change is also filtered for each shot (each energizing pulse of the solenoid valve) to determine whether the solenoid valve is successfully closed. Therefore, compared with the method of simply determining whether the solenoid valve is successfully closed based on whether the fuel pressure is reduced or increased, it is possible to detect whether the solenoid valve is successfully closed with high accuracy and directly.

[0140] In addition, the solenoid valve can be driven with the minimum current value, which can achieve significant silencing and power saving. Furthermore, there is no need to add a new control circuit, and the closing of the solenoid valve can be detected with the existing circuit. As a result, the development period can be greatly shortened and the cost can be greatly reduced.

[0141] 3. Third Implementation Method

[0142] Next, the solenoid valve control device of the third embodiment of the present invention is described. Among them, the solenoid valve control device of the third embodiment of the present invention has the same structure as the solenoid valve control device of the first embodiment described above. The difference between the solenoid valve control device of the third embodiment and the solenoid valve control device of the first embodiment lies in the control of the solenoid suction valve. Therefore, the control of the solenoid suction valve of the third embodiment is described here, and the description of the common structures such as the ECU (solenoid valve control device), the high-pressure fuel pump, and the solenoid suction valve is omitted.

[0143] [Control of electromagnetic suction valve]

[0144] For the control process of the electromagnetic suction valve 300 according to the third embodiment, refer to Fig.12 Provide explanation.

[0145] Fig.12 This is a flowchart of the solenoid valve control according to the third embodiment.

[0146] First, the ECU 109 (solenoid valve control device) performs scene determination (S301). In this process, it is determined whether to continue the feedback control (process of feeding back the driving current value whether the electromagnetic intake valve is successfully closed) according to the operation scene.

[0147] In S301, when it is determined that the scene is not for performing the feedback control (S301 is determined as NO), ECU109 (solenoid valve control device) ends the control. Thus, the feedback control is not implemented. On the other hand, in S301, when it is determined that the scene is for performing the feedback control (S301 is determined as YES), ECU109 (solenoid valve control device) performs the injection influence determination of the fuel injection valve 105 (S302).

[0148] The fuel discharge by the high-pressure fuel pump and the fuel injection by the fuel injection valve 105 are factors that greatly affect the fuel pressure of the common rail 129. Therefore, it is necessary to be careful about the present feedback control in the scenario where the two overlap.

[0149] Fig.13 : is a diagram showing the relationship between the fuel discharge of the high-pressure fuel pump, the fuel injection of the fuel injection valve, the fuel pressure of the common rail, and the fuel pressure after filtering according to the third embodiment of the present invention. Fig.13 As shown in FIG. 1 , when the fuel discharge 602 of the high-pressure fuel pump 125 and the fuel injection 1201 of the fuel injection valve 105 are at the same timing, the increase in fuel pressure caused by the fuel discharge 602 of the high-pressure fuel pump 125 is offset by the decrease in fuel pressure caused by the fuel injection 1201 of the fuel injection valve 105. As a result, the fuel pressure 1202 in the common rail 129 does not change, and the closing of the electromagnetic suction valve 300 cannot be detected based on the pressure change. In this case, the ECU 109 (electromagnetic valve control device) determines that the fuel injection 1201 performed by the fuel injection valve 105 affects the feedback control.

[0150] Since the fuel pressure 1202 in the common rail 129 has pulsations, it is assumed that there is actually no Fig.13 The scene shown in FIG. 6 is a scene in which the timing of fuel discharge 602 and fuel injection 1201 completely overlap. However, in the scene in which discharge and injection overlap slightly, the actual pressure change is confirmed, and the settings such as thresholds and detection windows are considered to study whether this feedback control can be applied. The range in which the high-pressure fuel pump 125 can discharge fuel is only the range in which the plunger 302 rises (from the bottom dead center to the top dead center of the cam). Therefore, when the fuel injection pulse slightly overlaps with the range in which the plunger 302 rises, it can be determined that the fuel injection performed by the fuel injection valve 105 affects this feedback control.

[0151] If it is determined in S302 that the fuel injection by the fuel injection valve 105 affects the present feedback control (YES in S302), the ECU 109 (solenoid valve control device) ends the control. Thus, the present feedback control is not performed.

[0152] On the other hand, in S302, when it is determined that the fuel injection by the fuel injection valve 105 has no influence on the present feedback control (determination is YES in S302), the ECU 109 (solenoid valve control device) performs the processing of S303 to S307. The processing of S303 to S307 is the same as the processing of S101 to S105 of the solenoid valve control of the first embodiment. Therefore, the description of the processing of S303 to S307 is omitted here.

[0153] In the solenoid valve control of the third embodiment, the pressure change is also filtered for each shot (each energization pulse of the solenoid valve) to determine whether the solenoid valve is successfully closed. Therefore, compared with the method of simply determining whether the solenoid valve is successfully closed based on whether the fuel pressure is reduced or increased, it is possible to detect whether the solenoid valve is successfully closed with high accuracy and directly.

[0154] In addition, the solenoid valve can be driven with the minimum current value, which can achieve significant silencing and power saving. Furthermore, there is no need to add a new control circuit, and the closing of the solenoid valve can be detected with the existing circuit. As a result, the development period can be greatly shortened and the cost can be greatly reduced.

[0155] 4. Fourth Implementation Method

[0156] Next, the electromagnetic valve control device of the fourth embodiment of the present invention is described. Among them, the electromagnetic valve control device of the fourth embodiment of the present invention has the same structure as the electromagnetic valve control device of the first embodiment described above. The difference between the electromagnetic valve control device of the fourth embodiment and the electromagnetic valve control device of the first embodiment is that a fuel injection valve is used as the electromagnetic valve. Here, the fuel injection valve of the fourth embodiment is described, and the description of the common structure of the ECU (electromagnetic valve control device), the fuel injection valve, etc. is omitted.

[0157] [Control of electromagnetic suction valve]

[0158] For the control process of the fuel injection valve 105 in the fourth embodiment, refer to Fig.14 Provide explanation.

[0159] Fig.14 This is a flowchart of the solenoid valve control according to the fourth embodiment.

[0160] When the electromagnetic suction valve 300 of the high-pressure fuel pump 125 is closed successfully, the fuel pressure in the common rail 129 increases. On the other hand, when the fuel injection valve 105 is closed successfully, the fuel pressure in the common rail 129 decreases. In this way, the electromagnetic suction valve 300 of the high-pressure fuel pump 125 and the fuel injection valve 105 are in a directly opposite relationship, so part of the electromagnetic valve control is different.

[0161] First, ECU 109 (solenoid valve control device) performs scene determination (S401). In this process, it is determined whether to continue the feedback control (processing of feeding back the driving current value whether the fuel injection valve is successfully closed) according to the operation scene. The operation scene is the same as the second embodiment.

[0162] In S401, when it is determined that the scene is not for performing the feedback control (determined as NO in S401), ECU109 (solenoid valve control device) ends the control. Thus, the feedback control is not implemented. On the other hand, in S401, when it is determined that the scene is for performing the feedback control (determined as YES in S401), ECU109 (solenoid valve control device) performs a discharge influence determination of the high-pressure fuel pump 125 (S402).

[0163] As described above, when the fuel discharge of the high-pressure fuel pump 125 and the fuel injection of the fuel injection valve 105 are at the same time, the increase in fuel pressure caused by the fuel discharge of the high-pressure fuel pump 125 is offset by the decrease in fuel pressure caused by the fuel injection of the fuel injection valve 105. As a result, the fuel pressure in the common rail 129 does not change, and the closing of the fuel injection valve 105 cannot be detected based on the pressure change. In this case, the ECU 109 (solenoid valve control device) determines that the fuel discharge by the high-pressure fuel pump 125 affects the feedback control. For example, when the fuel injection pulse slightly overlaps with the range from the top dead center to the bottom dead center of the cam, it can be determined that the fuel discharge by the high-pressure fuel pump 125 affects the feedback control.

[0164] If it is determined in S402 that the fuel discharge by the high-pressure fuel pump 125 affects the present feedback control (YES in S402), the ECU 109 (solenoid valve control device) ends the control. Thus, the present feedback control is not performed.

[0165] On the other hand, in S402, when it is determined that the fuel discharge by the high-pressure fuel pump 125 has no influence on the present feedback control (determination is YES in S402), the ECU 109 (solenoid valve control device) performs the processing of S403 and S404. The processing of S403 and S404 is the same as the processing of S101 and S102 of the solenoid valve control of the first embodiment. Therefore, the description of the processing of S403 and S404 is omitted here.

[0166] After the processing of S404, the ECU 109 (solenoid valve control device) compares the pressure data after filtering with a preset threshold value to determine whether the fuel injection valve 105 is successfully closed (S405). When the fuel injection valve 105 is successfully closed, the fuel pressure in the common rail 129 decreases. Therefore, the threshold is set to a negative value, and when the fuel pressure data after filtering is less than the threshold value, it is determined that the valve is closed successfully. In addition, when the fuel pressure data after filtering is above the threshold value, it is determined that the valve is closed unsuccessfully.

[0167] In S405, when it is determined that the valve closing is successful (YES in S405), ECU109 (solenoid valve control device) determines that the current current setting value is excessive. Then, ECU109 (solenoid valve control device) corrects the current setting value to a value lower than the current setting value (S406). After that, ECU109 (solenoid valve control device) obtains fuel pressure data again. That is, ECU109 (solenoid valve control device) returns the process to S403.

[0168] On the other hand, in S405, when it is determined that the valve closing fails (determined as NO in S405), ECU109 (solenoid valve control device) determines that the current current setting value is low. Then, ECU109 (solenoid valve control device) corrects the current setting value to a value higher than the current setting value (S407). After that, ECU109 (solenoid valve control device) determines that the current setting value corrected in the process of S407 is the necessary minimum current value and ends the control.

[0169] The conversion from injection flow rate to pressure change can be calculated based on pressure, volume, fuel properties, etc. using the formula for compressible fluid. Conversely, the injection flow rate of the fuel injection valve can also be calculated based on the change in the measurement signal (pressure data after differential filtering). In the process of S405, the injection flow rate of the fuel injection valve can be calculated, and it is determined whether to correct the current setting value to a lower value or a higher value based on the calculated injection flow rate. For example, when the calculated injection flow rate of the fuel injection valve is less than a predetermined specific value, it is determined to be the same as the case where the valve closing is successful (determined as YES). On the other hand, when the calculated injection flow rate of the fuel injection valve is above a specific value, it is determined to be the same as the case where the valve closing fails (determined as NO).

[0170] In the solenoid valve control of the fourth embodiment, the pressure change is also filtered for each shot (each energization pulse of the solenoid valve) to determine whether the solenoid valve is successfully closed. Therefore, compared with the method of simply determining whether the solenoid valve is successfully closed based on whether the fuel pressure is reduced or increased, it is possible to detect whether the solenoid valve is successfully closed with high accuracy and directly.

[0171] In addition, the solenoid valve can be driven with the minimum current value, which can achieve significant silencing and power saving. Furthermore, there is no need to add a new control circuit, and the closing of the solenoid valve can be detected with the existing circuit. As a result, the development period can be greatly shortened and the cost can be greatly reduced.

[0172] 5. Summary

[0173] As described above, the solenoid valve control device (ECU109) of the above embodiment controls the opening and closing of the solenoid valve in the internal combustion engine system including a plunger (plunger 302) that increases and decreases the volume of the pressurizing chamber (pressurizing chamber 311) by moving up and down with the rotation of the pump driving cam (pump driving cam 301), a solenoid valve (electromagnetic suction valve 300) for sucking fuel into the pressurizing chamber, a discharge valve (discharge valve 310) for discharging the fuel from the pressurizing chamber, and a fuel rail (common rail 129) for accumulating the fuel discharged by the fuel pump. In addition, the solenoid valve control device includes a control unit (microcomputer 220) that determines whether the solenoid valve is successfully closed based on the fuel pressure of the fuel rail, or calculates the discharge amount achieved by the closing of the solenoid valve based on the fuel pressure of the fuel rail. As a result, the movement of the valve body corresponding to the drive instruction, that is, the closing of the solenoid valve, can be detected without adding a special circuit such as a low-pass filter circuit or an operational amplifier circuit.

[0174] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU 109) of the above embodiment determines whether the solenoid valve (solenoid suction valve 300) is successfully closed or calculates the discharge amount achieved by closing the solenoid valve based on the measurement signal output from the fuel pressure sensor (fuel pressure sensor 126) installed in the fuel rail (common rail 129). As a result, the fuel pressure in the fuel rail can be easily obtained.

[0175] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU 109) of the above-mentioned embodiment filters the measurement signal output from the fuel pressure sensor (fuel pressure sensor 126), compares the filtered measurement signal with a predetermined threshold value, thereby determining whether the solenoid valve (solenoid suction valve 300) is successfully closed, or calculating the discharge amount achieved by the solenoid valve closing. As a result, the accuracy of whether the solenoid valve is successfully closed can be improved. In addition, the accuracy of the calculated discharge amount achieved by the solenoid valve closing can be improved.

[0176] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU 109) of the above embodiment determines that the solenoid valve (solenoid suction valve 300) has closed successfully when the amount of change in the measurement signal output from the fuel pressure sensor (fuel pressure sensor 126) is greater than a predetermined threshold value, and determines that the solenoid valve has failed to close when it is below the threshold value. Thus, the movement of the valve body corresponding to the drive command, that is, the closing of the solenoid valve, can be easily detected.

[0177] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU 109) of the above-mentioned embodiment calculates the discharge amount achieved by closing the solenoid valve (solenoid suction valve 300) based on the change amount of the measurement signal output from the fuel pressure sensor (fuel pressure sensor 126). As a result, the discharge amount achieved by closing the valve can be easily detected. Moreover, the discharge amount achieved by closing the valve corresponds to the movement of the valve body corresponding to the drive command.

[0178] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU109) of the above embodiment corrects the peak value of the driving current supplied to the solenoid valve to a value lower than the current setting value when judging that the solenoid valve (electromagnetic suction valve 300) has closed successfully, and corrects the peak value of the driving current supplied to the solenoid valve to a value higher than the current setting value when judging that the solenoid valve has failed to close. Thus, the solenoid valve can be driven with the minimum current value, and noise reduction and power saving can be achieved.

[0179] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU109) of the above embodiment corrects the peak value of the driving current supplied to the solenoid valve to a value lower than the current setting value when the fuel discharge amount achieved by closing the solenoid valve (electromagnetic suction valve 300) is greater than the specified value, and corrects the peak value of the driving current supplied to the solenoid valve to a value higher than the current setting value when the fuel discharge amount achieved by closing the solenoid valve is less than the specified value. Thus, the solenoid valve can be driven with the minimum current value, and noise reduction and power saving can be achieved.

[0180] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU 109) of the above-mentioned embodiment determines whether the valve is closed successfully or calculates the discharge amount achieved by closing the valve for each energizing pulse of the solenoid valve (solenoid suction valve 300) based on the fuel pressure of the fuel rail (common rail 129). Therefore, it is possible to detect whether the solenoid valve is closed successfully more directly than a method of simply judging whether the solenoid valve is closed successfully based on whether the fuel pressure is reduced or increased.

[0181] In addition, when the fuel injection pulse applied to the fuel injection valve (fuel injection valve 105) disposed on the downstream side of the fuel rail (common rail 129) and injecting fuel into the combustion chamber (combustion chamber 121) of the engine is within the set range, the control unit (microcomputer 220) of the solenoid valve control device (ECU109) of the above embodiment determines whether the solenoid valve (electromagnetic intake valve 300) is successfully closed based on the fuel pressure of the fuel rail, or calculates the discharge amount achieved by closing the solenoid valve, and implements solenoid valve control to control the closing or opening action of the solenoid valve based on the judgment result or the calculation result. As a result, it is possible to detect whether the solenoid valve is successfully closed or calculate the discharge amount achieved by closing the valve in consideration of the fuel injection timing of the fuel injection valve. As a result, it is possible to improve the accuracy of the calculated value of whether the solenoid valve is successfully closed or the discharge amount achieved by closing the valve. In addition, because the solenoid valve control is implemented based on the accurate detection of whether the solenoid valve is successfully closed or the accurate calculation of the discharge amount achieved by closing the valve, it is possible to improve the accuracy of driving the solenoid valve with the minimum current value.

[0182] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU109) of the above-mentioned embodiment implements solenoid valve control when it is determined that the injection pulse applied to the fuel injection valve (fuel injection valve 105) does not interfere with the fuel discharge timing of the fuel pump (high-pressure fuel pump 125). As a result, it is possible to detect whether the solenoid valve is successfully closed or calculate the discharge amount achieved by closing the valve when the fuel pressure in the fuel rail changes. As a result, the accuracy of calculating whether the solenoid valve is successfully closed or the discharge amount achieved by closing the valve can be improved. In addition, because the solenoid valve control is implemented based on the accurate detection of whether the solenoid valve is successfully closed or the accurate calculation of the discharge amount achieved by closing the valve, the accuracy of driving the solenoid valve with the minimum current value can be improved.

[0183] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU 109) of the above embodiment performs a solenoid valve diagnosis process to determine whether the solenoid valve (solenoid intake valve 300) is successfully closed or calculate the discharge amount achieved by closing the solenoid valve based on the fuel pressure of the fuel rail (common rail 129) when the engine is idling. This can reduce noise during idling.

[0184] In addition, the control unit (microcomputer 220) of the solenoid valve control device (ECU 109) of the above-mentioned embodiment performs a solenoid valve diagnosis process for determining whether the solenoid valve (solenoid intake valve 300) is successfully closed or calculating the discharge amount achieved by closing the solenoid valve based on the fuel pressure of the fuel rail (common rail 129) in a scenario where the engine can be operated in a steady state. As a result, the solenoid valve diagnosis process can be performed in a scenario where external interference is small and changes in fuel pressure and discharge amount are small, so the accuracy of calculating whether the solenoid valve is successfully closed or the discharge amount achieved by closing the valve can be improved.

[0185] In addition, the solenoid valve control device (ECU109) of the above embodiment controls the opening and closing of the fuel injection valve in the internal combustion engine system including a plunger (plunger 302) that increases and decreases the volume of the pressurizing chamber (pressurizing chamber 311) by moving up and down with the rotation of the (pump driving cam 301), a solenoid valve (solenoid suction valve 300) for sucking fuel into the pressurizing chamber, a discharge valve (discharge valve 310) for discharging the fuel from the pressurizing chamber, a fuel rail (common rail 129) for accumulating the fuel discharged from the fuel pump, and a fuel injection valve (fuel injection valve 105) arranged on the downstream side of the fuel rail and injecting fuel into the combustion chamber (combustion chamber 121) of the engine. In addition, the solenoid valve control device includes a control unit (microcomputer 220) that determines whether the fuel injection valve is successfully closed based on the fuel pressure of the fuel rail, or calculates the discharge amount achieved by closing the fuel injection valve based on the fuel pressure of the fuel rail. Thus, the movement of the valve body corresponding to the drive command, that is, the closing of the fuel injection valve can be detected without adding a special circuit such as a low-pass filter circuit or an operational amplifier circuit.

[0186] The embodiments of the solenoid valve control device according to the present invention have been described above, including the operations and effects thereof.

[0187] However, the solenoid valve control device of the present invention is not limited to the above-described embodiment, and can be implemented in various modified forms without departing from the gist of the invention described in the claims.

[0188] In addition, the above-mentioned embodiments are described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and are not limited to all structures that must be described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0189] For example, the above embodiment is applied to a normally open electromagnetic valve in which the valve body opens when no current flows through the solenoid and closes when current flows through the solenoid. However, the electromagnetic valve control device of the present invention can also be applied to a normally closed electromagnetic valve in which the valve body opens when current flows through the solenoid and closes when no current flows through the solenoid.

[0190] Description of Reference Numerals

[0191] 101…Internal Combustion Engine

[0192] 102…Piston

[0193] 103…Suction valve

[0194] 104…Exhaust valve

[0195] 105…Fuel injection valve

[0196] 109…ECU

[0197] 110…Suction pipe

[0198] 111…Exhaust pipe

[0199] 121…Combustion chamber

[0200] 123…Fuel tank

[0201] 124…Low pressure fuel pump

[0202] 125…High pressure fuel pump

[0203] 126…Fuel pressure sensor

[0204] 128…Exhaust cam

[0205] 129…Common rail

[0206] 201…Sensors

[0207] 202…Input signal

[0208] 203…Input circuit

[0209] 204…A / D conversion unit

[0210] 205…CPU

[0211] 206…Signal line

[0212] 210…Output circuit

[0213] 211…Control signal

[0214] 212…Actuators

[0215] 220…Microcomputer

[0216] 300...Solenoid suction valve

[0217] 301…Pump drive cam

[0218] 302…Plunger

[0219] 303…Valve body

[0220] 303a…butt piece

[0221] 304…Armature

[0222] 305…Solenoid

[0223] 306…Fixed part (magnetic core)

[0224] 307… Seat

[0225] 308…Stop

[0226] 309…1st spring

[0227] 310…Discharge valve

[0228] 311…Compression chamber

[0229] 315…2nd spring

[0230] 321…Connection port

[0231] 322…Outflow

[0232] 323…Housing

[0233] 325…Inlet

[0234] 355…Pressure reducing valve.

Claims

1. A solenoid valve control device, which controls the opening and closing of a solenoid valve in an internal combustion engine system, wherein: The internal combustion engine system includes: a fuel pump having a plunger that increases or decreases the volume of a pressurizing chamber by moving up and down as a pump driving cam rotates, the solenoid valve for sucking fuel into the pressurizing chamber, and a discharge valve for discharging the fuel from the pressurizing chamber; and a fuel rail for accumulating the fuel discharged by the fuel pump, wherein the solenoid valve control device is characterized in that: A control unit is included, which determines whether the solenoid valve is successfully closed based on the fuel pressure of the fuel rail, or calculates the discharge amount achieved by closing the solenoid valve based on the fuel pressure of the fuel rail, The control unit filters a measurement signal output from a fuel pressure sensor installed in the fuel rail, and compares the filtered measurement signal with a predetermined threshold value, thereby determining whether the solenoid valve is successfully closed or calculating a discharge amount achieved by closing the solenoid valve.

2. The solenoid valve control device according to claim 1, characterized in that: The control unit determines that the solenoid valve has closed successfully when the amount of change in the measurement signal output from the fuel pressure sensor is larger than a predetermined threshold, and determines that the solenoid valve has failed to close when the amount of change in the measurement signal output from the fuel pressure sensor is smaller than the threshold.

3. The solenoid valve control device according to claim 1, characterized in that: The control unit calculates a discharge amount achieved by closing the solenoid valve based on an amount of change in a measurement signal output from the fuel pressure sensor.

4. The solenoid valve control device according to claim 1, characterized in that: When the control unit determines that the solenoid valve has closed successfully, the control unit will correct the peak value of the driving current supplied to the solenoid valve to a value lower than the current set value. When the control unit determines that the solenoid valve has failed to close, the control unit will correct the peak value of the driving current supplied to the solenoid valve to a value higher than the current set value.

5. The solenoid valve control device according to claim 1, characterized in that: The control unit, when the amount of fuel discharge achieved by closing the solenoid valve is greater than a prescribed value, corrects the peak value of the driving current supplied to the solenoid valve to a value lower than the current set value; and when the amount of fuel discharge achieved by closing the solenoid valve is less than the prescribed value, corrects the peak value of the driving current supplied to the solenoid valve to a value higher than the current set value.

6. The solenoid valve control device according to claim 1, characterized in that: The control unit determines whether the valve is closed successfully for each energization pulse of the solenoid valve based on the fuel pressure of the fuel rail, or calculates a discharge amount achieved by closing the valve for each energization pulse of the solenoid valve.

7. The solenoid valve control device according to claim 1, characterized in that: The control unit determines whether the solenoid valve is successfully closed based on the fuel pressure of the fuel rail, or calculates the discharge amount achieved by closing the solenoid valve, when a fuel injection pulse applied to a fuel injection valve disposed on the downstream side of the fuel rail and injecting fuel into a combustion chamber of the engine is within a set range, and performs solenoid valve control to control the closing or opening action of the solenoid valve based on the determination result or the calculation result.

8. The solenoid valve control device according to claim 7, characterized in that: The control unit performs the solenoid valve control when it is determined that the injection pulse applied to the fuel injection valve does not interfere with the fuel discharge timing of the fuel pump.

9. The solenoid valve control device according to claim 7, characterized in that: The control unit performs a solenoid valve diagnosis process for determining whether the solenoid valve is successfully closed or calculating a discharge amount achieved by closing the solenoid valve based on the fuel pressure of the fuel rail when the engine is idling.

10. The solenoid valve control device according to claim 7, characterized in that: The control unit performs a solenoid valve diagnosis process to determine whether the solenoid valve is successfully closed or calculate a discharge amount achieved by closing the solenoid valve based on the fuel pressure of the fuel rail when the engine is capable of steady-state operation.

11. A solenoid valve control device for controlling the opening and closing of a fuel injection valve in an internal combustion engine system, wherein: The internal combustion engine system includes: a fuel pump having a plunger that increases or decreases the volume of a pressurizing chamber by moving up and down as a pump driving cam rotates, a solenoid valve for sucking fuel into the pressurizing chamber, and a discharge valve for discharging the fuel from the pressurizing chamber; a fuel rail for accumulating the fuel discharged by the fuel pump; and the fuel injection valve disposed on the downstream side of the fuel rail and injecting fuel into a combustion chamber of the engine, wherein the solenoid valve control device is characterized in that: A control unit is included, which determines whether the fuel injection valve is successfully closed based on the fuel pressure of the fuel rail, or calculates the discharge amount achieved by closing the fuel injection valve based on the fuel pressure of the fuel rail, The control unit filters a measurement signal output from a fuel pressure sensor installed in the fuel rail, and compares the filtered measurement signal with a predetermined threshold value, thereby determining whether the solenoid valve is successfully closed or calculating a discharge amount achieved by closing the solenoid valve.

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