Control device of electromagnetic actuator

Abstract

The purpose of the present invention is to accurately detect the operating state of a movable element of an electromagnetic actuator. A control device (10) is a device for controlling an electromagnetic actuator (200) having a stator (206), a coil (205), and a movable element (204) that operates on the basis of a current supplied to the coil (205). A control device (10) is provided with: an energizing unit (11) that switches energization to a coil (205) and supplies a switching current to the coil (205); and a switching detection unit (13) that detects the increase and decrease in the switching current. A switching state calculation unit (14) that calculates a ratio (T1 / T2) between the rise time (T1) and the fall time (T2); a switch state change detection unit (15) that detects a change in the calculated ratio; and an operation state detection unit (16) that detects the operation state of the movable element (204) on the basis of the detected change in the ratio.

Description

Technical Field

[0001] This invention relates to a control device for electromagnetic actuators. Background Technology

[0002] Vehicle internal combustion engines require high efficiency, high output, and low emissions. Direct injection internal combustion engines have long been widely adopted as a means of achieving a balanced solution to these problems. Key challenges in direct injection internal combustion engines include minimizing the noise of the high-pressure fuel pump that pressurizes the fuel, and increasing the precision of the fuel injection quantity into the cylinders via the injectors.

[0003] High-pressure fuel pumps are equipped with electromagnetic actuators that control the amount of fuel drawn in. Silencing the high-pressure fuel pump requires reducing the impact speed of the valve core during valve closing, which can be achieved by reducing the drive current used for valve closing. However, if the drive current is reduced too low, valve closing will fail. The minimum drive current, which is the limit for valve closing without failure, varies from high-pressure fuel pump to high-pressure pump due to individual differences in the electromagnetic actuators controlling the opening and closing of the valve core. The minimum drive power used for valve closing depends on the force of the spring pushing the valve core. The stronger the spring force, the greater the power required to overcome that force and close the valve. On the other hand, the stronger the spring force, the slower the valve closing. Therefore, electromagnetic actuators with slower valve closing require a larger minimum drive power setting.

[0004] The injector has an electromagnetic actuator that controls the amount of fuel injected. Even when driven by the same current, the injection quantity varies from injector to injector due to individual differences in the electromagnetic actuator. Since there is a correlation between the valve closing time and the injection quantity, the deviation in injection quantity can be reduced by controlling the drive current to make the valve closing time consistent.

[0005] As these examples illustrate, in order to achieve quiet operation of high-pressure fuel pumps or high precision in injector injection volume, it is necessary to accurately detect the valve spool's closing time. As a technique for detecting the valve closing time, the technique disclosed in Patent Document 1 is known.

[0006] Patent Document 1 discloses a high-pressure fuel pump comprising a valve core that opens and closes an inlet for fuel to flow into a pressurization chamber at its top, a movable member disposed at the base end of the valve core, and a stator that attracts the movable member by energizing a coil. The high-pressure fuel pump is characterized by having an electromagnetic actuator that supplies current to the coil, the current varying within a certain range and having a frequency above a set value, the timing of the variation falling within the set range.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2021-32178 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] The drive current of the electromagnetic actuator in a high-pressure fuel pump or injector is generally divided into two parts: a peak current that provides energy to the valve core and moving parts when stationary in the open position, and a holding current that maintains the moving parts' actuation state to keep the valve core in the closed position. The holding current is supplied to the coil of the electromagnetic actuator as a switching current with a periodic amplitude variation within a certain range. The valve closing time is determined by the actuation state of the moving parts, and from the viewpoint of reducing drive power and minimizing noise, it is advisable to control it to arrive during the period when the holding current is supplied.

[0012] In the technology disclosed in Patent Document 1, the valve closing time is detected by detecting changes in the frequency of the holding current. However, the inventors have discovered that the frequency of the holding current increases or decreases with valve closing, depending on the voltage (power supply voltage) of the battery that supplies the current to the coil. Since the timing of changes in the frequency of the holding current varies with the power supply voltage, the technology disclosed in Patent Document 1 has room for improvement in ensuring robustness to the power supply voltage. The ability to accurately detect the operating state of the movable part without relying on the power supply voltage is also an important issue for electromagnetic actuators other than those used for high-precision control of high-pressure fuel pumps or injectors.

[0013] The present invention was made in view of the above-mentioned problems, and its purpose is to accurately detect the operating state of the movable part of an electromagnetic actuator.

[0014] Methods for solving problems

[0015] To solve the above problems, the control device for the electromagnetic actuator of the present invention is a control device for controlling an electromagnetic actuator. This electromagnetic actuator has a stator, a coil fixed to the stator, and a movable member that operates based on a current supplied to the coil. The control device for the electromagnetic actuator is characterized by comprising: an energizing unit that switches the energization of the coil to supply a switching current to the coil; a switching detection unit that detects rises and falls in the switching current supplied to the coil; a switching state calculation unit that calculates the ratio between the time when the rise is detected and the time when the fall is detected; a switching state change detection unit that detects changes in the calculated ratio; and an operation state detection unit that detects the operation state of the movable member based on the detected change in the ratio.

[0016] The effects of the invention

[0017] According to the present invention, the operating state of the movable part of the electromagnetic actuator can be accurately detected.

[0018] Other issues, structures, and effects not mentioned above will be clarified through the following description of the implementation methods. Attached Figure Description

[0019] Figure 1 It is a diagram illustrating the general structure of a direct injection internal combustion engine.

[0020] Figure 2 This is a diagram illustrating the structure of a high-pressure fuel pump.

[0021] Figure 3 This is a timing diagram illustrating the operation of the high-pressure fuel pump.

[0022] Figure 4 (a) is a diagram illustrating the displacement of the valve core and moving parts when the valve is successfully closed. Figure 4 (b) is a diagram illustrating the displacement of the valve core and moving parts when the valve fails to close.

[0023] Figure 5 It is a diagram illustrating the relationship between the displacement of the plunger and the fuel pressure in the high-pressure piping.

[0024] Figure 6 It is a graph illustrating the relationship between the peak current supply and the speed of the movable part just before the valve closes.

[0025] Figure 7 This is a graph illustrating the relationship between the valve closing time and the noise level.

[0026] Figure 8 This is a diagram illustrating the structure of the control device for an electromagnetic actuator.

[0027] Figure 9 It is a diagram illustrating the details of the current supplied to the coil.

[0028] Figure 10 This is an explanation Figure 8 The diagram shows the specific configuration of the switch detection unit, switch state calculation unit, and switch state change detection unit.

[0029] Figure 11 This is an explanation Figure 10 The diagram shows the outputs of the differentiating circuit, the positive / negative determination circuit, the smoothing circuit, and the inflection point extraction circuit.

[0030] Figure 12 This diagram illustrates the specific configuration of the switch detection unit, switch state calculation unit, and switch state change detection unit in Embodiment 2.

[0031] Figure 13 This is an explanation Figure 12The diagram shows the outputs of the power-on detection circuit, the smoothing circuit, and the inflection point extraction circuit. Detailed Implementation

[0032] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, for components or functions marked with the same symbols in each embodiment, unless specifically mentioned, their descriptions are omitted as they have the same components or functions in each embodiment.

[0033] [Implementation Method 1]

[0034] use Figures 1 to 11 The control device 10 of the electromagnetic actuator 200 in Embodiment 1 will be described.

[0035] Figure 1 This is a diagram illustrating the general structure of a direct injection internal combustion engine 100.

[0036] In the direct injection internal combustion engine 100 (hereinafter also referred to as "internal combustion engine 100"), the fuel stored in the fuel tank 101 is pressurized to about 0.4 MPa in the supply pump 102, and then pressurized to tens of MPa in the high-pressure fuel pump 103. The pressurized fuel is injected from the injector 105 into the cylinder 106 of the internal combustion engine 100 via the high-pressure pipe 104.

[0037] The injected fuel mixes with the air drawn into the cylinder 106 via the action of piston 107. This mixture is ignited and exploded by a spark generated by spark plug 108. Due to the heat generated by the explosion, the mixture inside cylinder 106 expands, pushing piston 107 down. The force pushing piston 107 down causes crankshaft 110 to rotate via connecting rod mechanism 109. The rotation of crankshaft 110 is transmitted to the wheels through the transmission, becoming the force that moves the vehicle.

[0038] The internal combustion engine 100 primarily requires high efficiency, high output, and low emissions; as a further added value, noise and vibration reduction are also required. In the high-pressure fuel pump 103, noise is generated during the opening and closing of the valve core 203, which constitutes the intake valve, due to collisions between the valve core 203 and the stop block 208, or between the movable part (armature) 204 and the stator 206, and between the valve core 203 and the valve seat 207. Automakers and suppliers are competing to reduce noise.

[0039] Figure 2 This is a diagram illustrating the structure of the high-pressure fuel pump 103.

[0040] The high-pressure fuel pump 103 includes a plunger 202 that moves up and down by the rotation of a cam 201 mounted on the camshaft of the internal combustion engine 100, a valve core 203 that forms an intake valve that opens and closes synchronously with the up and down movement of the plunger 202, and an electromagnetic actuator 200 that controls the opening and closing of the valve core 203.

[0041] The high-pressure fuel pump 103 has a housing 223, inside which a pressurization chamber 211 is provided. Fuel flows into the pressurization chamber 211 from the low-pressure piping 111 through the inlet 225 and the connecting port 221. The fuel flowing into the pressurization chamber 211 is discharged to the high-pressure piping 104 through the outlet 222. The outlet 222 is opened and closed by a discharge valve 210. The discharge valve 210 is always forced by a spring 226 to close the outlet 222. When the pressure (fuel pressure) in the pressurization chamber 211 overcomes the reaction force of the spring 226, the outlet 222 opens and fuel is discharged.

[0042] The inflow of fuel into the pressurization chamber 211 is restricted by the valve core 203 that opens and closes the inlet 225. The opening and closing action of the valve core 203 is controlled by an electromagnetic actuator 200. The electromagnetic actuator 200 is a device that converts electrical energy into mechanical energy through magnetic energy. The electromagnetic actuator 200 has a stator 206 as a magnetic core, a coil 205 fixed on the stator 206, and a movable element 204 that operates based on the current supplied to the coil 205.

[0043] The movable element 204 abuts against the valve core 203, which is stressed by the spring 215, thus restricting the movement of the valve core 203. The opening and closing of the valve core 203 is controlled by the movement of the movable element 204, which in turn causes the valve core 203 to move. The movable element 204 is attracted by the stator 206 by the magnetic force generated by the current supplied to the coil 205, causing the valve core 203 to move. That is, the axial movement of the movable element 204 is controlled by controlling the energization of the coil 205. Figure 2 (Movement in the left and right directions).

[0044] The movable element 204 is connected to the stator 206 via a spring 209. The movable element 204 is always directed by the spring 209 in the valve opening direction. Figure 2 A force is applied to the right side. Thus, the movable element 204 holds the valve core 203 in the open position when the coil 205 is de-energized. Such a high-pressure fuel pump 103 is called a normally open type high-pressure fuel pump. This embodiment describes the normally open type, but if the open and closed valves are replaced, a normally closed type can also be applied.

[0045] When coil 205 is energized, an electromagnetic attraction is generated between stator 206 and movable member 204. When this electromagnetic attraction overcomes the reaction force of spring 209, movable member 204, located at the base end of valve core 203, is moved towards the valve closing direction. Figure 2The movable element 204 is attracted by the stator 206. With the movable element 204 attracted by the stator 206, the valve core 203 becomes a one-way valve that opens and closes based on the pressure difference between the upstream and downstream sides of the valve core 203 and the reaction force of the spring 215. Therefore, by magnetically attracting the movable element 204 towards the closing direction, the valve core 203 is pushed by the spring 215 and moves towards the closing direction. When the valve core 203 moves only a set lift towards the closing direction, the valve core 203 sits on the valve seat 207, becoming a closed valve. When the valve core 203 is in the closed valve state, the fuel in the pressurized chamber 211 cannot flow backwards to the low-pressure piping 111.

[0046] Figure 3 This is a timing diagram illustrating the operation of the high-pressure fuel pump 103.

[0047] To synchronize the opening and closing actions of the valve core 203 and the plunger 202, the rotation angle of the cam 201 is detected. For example, after the cam 201 has rotated a fixed angle from the top dead center (TDC) (at time P_ON), ​​a voltage V is applied to the two ends of the coil 205 (at time t1). Through this voltage V, the current I flowing through the coil 205 increases according to Equation 1.

[0048] LdI / dt=V-RI…(Equation 1)

[0049] Here, L in Equation 1 is the inductance of coil 205 and wiring, and R in Equation 1 is the resistance of coil 205 and wiring. As the current I increases, the electromagnetic attraction Fmag of stator 206 attracting movable member 204 also increases.

[0050] When the electromagnetic attraction Fmag becomes greater than the reaction force Fsp of the spring 209, the movable part 204, which is pushed by the reaction force Fsp, begins to move toward the stator 206 (time t2). As the movable part 204 moves, it is pushed by the spring 215, and the valve core 203 also follows the movable part 204 to move toward the stator 206.

[0051] Soon after, the valve core 203 collided with the valve seat 207 and settled. Due to this collision, the fuel flow path ( Figure 2 (The dashed line) is blocked, and the fuel pressurized by the rise of plunger 202 cannot return to the low-pressure pipe 111 side, causing the pressure in pressurized chamber 211 to rise. (Time t4)

[0052] When the pressure in the pressurization chamber 211 exceeds the reaction force Fsp_out of the spring 226 that pushes the discharge valve 210, the discharge valve 210 opens, and the fuel pressurized by the rise of the plunger 202 is discharged into the high-pressure pipe 104. Then, at time t5, when the drive pulse becomes OFF, a reverse voltage is applied to the coil 205, thereby cutting off the holding current supplied to the coil 205.

[0053] When the cam angle exceeds the top dead center and the plunger 202 begins to descend (at time t6), the pressure in the pressurization chamber 211 decreases. When the pressure drops below the reaction force Fsp_out of the spring 226, the discharge valve 210 closes, and the fuel discharge ends.

[0054] In addition, as the pressure in the pressurization chamber 211 decreases, the movable part 204 moves together with the valve core 203 from the closed position to the open position (time t7~t8).

[0055] Through this action, the high-pressure fuel pump 103 delivers fuel from the low-pressure piping 111 to the high-pressure piping 104. During this process, the valve is closed at the moment when the movable element 204 collides with the stator 206 and the valve core 203 collides with the valve seat 207. Figure 3 The moment t4), and the moment when the valve core 203 collides with the stop block 208 to complete the valve opening ( Figure 3 Noise is generated at the moment t8. This noise is particularly noticeable when the internal combustion engine 100 is idling, causing discomfort to vehicle occupants. Automakers and suppliers are racing to reduce this noise. In this embodiment, the goal is to reduce noise at the moment the valve closes.

[0056] The drive current of the electromagnetic actuator 200 is roughly divided into peak current ( Figure 3 The sloping part of the current waveform) and the holding current ( Figure 3 The peak current is the current that provides energy to the movable element 204, which is pressed by the spring 209 and is stationary in the open position, causing the movable element 204 to start moving to close the valve. On the other hand, the holding current is the current that maintains the movable element 204 in contact with the stator 206, so as to attract the movable element 204 that is close to the stator 206 to collide with the stator 206, thereby holding the valve core 203 in the closed position. The valve closing time (hereinafter also referred to as "valve closing time Tb") is controlled to arrive during the period of supplying the holding current. If the peak current supply is reduced, the valve closing momentum is weakened, the speed of the valve core 203 and the movable element 204 during valve closing is reduced, and noise can be reduced. However, if the peak current supply is reduced too much, valve closing will fail. Therefore, it is important to minimize the peak current supply as much as possible within the range of successful valve closing. In addition, as Figure 3 As shown, the maximum value of the peak current is set to Im, and the maximum value of the holding current is set to Ik.

[0057] Figure 4 (a) is a diagram illustrating the displacement of the valve core 203 and the movable part 204 when the valve is successfully closed. Figure 4 (b) is a diagram illustrating the displacement of the valve core 203 and the movable part 204 when the valve fails to close. Figure 5This is a diagram illustrating the relationship between the displacement of plunger 202 and the fuel pressure of high-pressure piping 104. Figure 6 This is a graph illustrating the relationship between the peak current supply and the speed of the movable part 204 just before the valve closing is about to end. Figure 7 This is a graph illustrating the relationship between the valve closing time and the noise level.

[0058] The high-pressure fuel pump 103 compresses the fuel in the low-pressure pipe 111 and discharges it into the high-pressure pipe 104 to maintain the fuel pressure in the high-pressure pipe 104 at a target value. For this purpose, a fuel pressure sensor 250 is installed on the high-pressure pipe 104 to measure the fuel pressure. The control device 10 of the electromagnetic actuator 200 (see reference...) Figure 8 The current supply to coil 205 is started at the designated time (P_ON time) to ensure that the measured value of fuel pressure sensor 250 matches the target value. If the measured value of fuel pressure sensor 250 is lower than the target value, the current supply to coil 205 is started earlier to increase the discharge rate. If the measured value of fuel pressure sensor 250 is higher than the target value, the current supply to coil 205 is delayed to reduce the discharge rate. This control can typically be achieved using PID control.

[0059] As described above, reducing the peak current supply decreases the closing speed of the valve core 203, thus reducing noise. However, if the peak current supply is too low, valve closure will fail. That is, when a sufficient peak current supply is supplied to the coil 205 for valve closure, the valve core 203 and the movable element 204... Figure 4 The action shown in (a) (valve closure successful). Without supplying sufficient peak current to coil 205 to close the valve, valve core 203 and movable element 204 cannot overcome the reaction force of spring 209 to perform the valve closure. Figure 4 The action shown in (b) is (valve closure failure).

[0060] If the valve closes successfully, the valve core 203 blocks the inlet 225 from the low-pressure pipe 111 to the pressurization chamber 211, and the fuel pressure rising in the pressurization chamber 211 due to the rise of the plunger 202 is transmitted to the high-pressure pipe 104. Thus, as... Figure 5 As shown in the upper right diagonal section A, the fuel pressure in the high-pressure pipe 104 rises synchronously with the rise of the plunger 202. On the other hand, in the event of valve closure failure, even if the plunger 202 rises, fuel in the pressurization chamber 211 will escape to the low-pressure pipe 111 side. Therefore, as... Figure 5 As shown in the lower right slanted section B, even if the plunger 202 rises, the fuel pressure in the high-pressure pipe 104 will not rise.

[0061] The control device 10 of the electromagnetic actuator 200 can determine whether valve closure is successful or unsuccessful based on the measured value of the fuel pressure sensor 250 installed on the high-pressure pipe 104. In the case of valve closure failure, the control device 10 increases the current supply to the coil 205; in the case of successful valve closure, it decreases the current supply to the coil 205. Thus, by determining successful or unsuccessful valve closure based on the fuel pressure fluctuations in the high-pressure pipe 104 synchronized with the up-and-down movement of the plunger 202, and adjusting the current supply accordingly, the control device 10 can control the drive current of the electromagnetic actuator 200 near the minimum current supply required for successful valve closure. Therefore, the control device 10 can reduce the noise generated during valve closure by the electromagnetic actuator 200.

[0062] However, in the use Figure 5 When the drive current of the electromagnetic actuator 200 is controlled near the minimum current supply, valve closing failure occurs at a certain frequency. The inventors have studied the characteristics of the electromagnetic actuator 200 to avoid this valve closing failure. As a result, the inventors discovered that there exists a relationship between the peak current supply (peak current integral value II) and the velocity vel_Tb of the movable element 204 just before the valve closing is completed, such as... Figure 6 The dead zone D shown is where the speed vel_Tb does not decrease just before the valve closes, even if the peak current supply decreases. Additionally, Figure 6 The peak current supply shown is from Figure 3 The integral value of the drive current from the moment t1 when the peak current supply begins to the moment t3 when the peak current decreases.

[0063] When the maximum peak current value Im is given for a sufficiently long time, the movable element 204 is always accelerated. However, if the peak current width is shortened, the movable element 204 begins to decelerate from the moment the maximum peak current value Im is cut off. It then slides towards the stator 206 at a lower speed. Furthermore, as the movable element 204 approaches the stator 206, it is accelerated again by the electromagnetic attraction generated by the holding current. When accelerated again from a state of approximately zero speed by the electromagnetic attraction generated by the holding current, the movable element 204 moves at approximately a constant speed, independent of its previous movement. This is the reason for the dead zone D in the relationship between the peak current supply and the speed vel_Tb of the movable element 204 just before the valve closing is complete.

[0064] By considering the existence of this dead zone D, the relationship between the level of noise generated during valve closure and the valve closure end time Tb (the moment when the movable part 204 collides with the stator 206) is as follows: Figure 7As shown, there exists a saturation region Tr where the noise level does not decrease even if Tb changes at the valve closing time. This saturation region Tr does not differ significantly even with different power supply voltages for the electromagnetic actuator 200, becoming a region shared by various power supply voltages.

[0065] Even if the peak current supply is further reduced from the dead zone D, the speed vel_Tb of the movable element 204 just before the valve closing is completed cannot be reduced to a speed below the dead zone D; instead, the valve closing will fail. Therefore, when Tb exists in the saturation region Tr at the valve closing end time, valve closing failure can be suppressed, and the noise level accompanying valve closing can be minimized.

[0066] Therefore, the control device 10 of the electromagnetic actuator 200 can suppress valve closing failure and reduce noise associated with valve closing by controlling the current to maintain the valve closing end time Tb in the saturation region Tr. Specifically, when the valve closing end time Tb is earlier than the target time existing in the saturation region Tr, the control device 10 reduces the current supplied to the coil 205; when the valve closing end time Tb is later than the target time existing in the saturation region Tr, the control device 10 increases the current supplied to the coil 205. Thus, the control device 10 can control the drive current to maintain the valve closing end time Tb in the saturation region Tr, thereby suppressing valve closing failure and reducing noise associated with valve closing.

[0067] To achieve control that maintains the valve closing time Tb within the saturation region Tr, accurate detection of the valve closing time Tb is required. Therefore, the following section uses... Figures 8-11 The control device 10 of the electromagnetic actuator 200, which can accurately detect the valve closing time Tb, will be described.

[0068] Figure 8 This is a diagram illustrating the configuration of the control device 10 of the electromagnetic actuator 200. Figure 9 This is a diagram that details the current supplied to coil 205. Figure 10 This is an explanation Figure 8 The diagram shows the specific configuration of the switch detection unit 13, the switch state calculation unit 14, and the switch state change detection unit 15. Figure 11 This is an explanation Figure 10 The diagram shows the outputs of the differentiating circuit 17, the positive / negative determination circuit 18, the smoothing circuit 19, and the inflection point extraction circuit 20.

[0069] The two ends of the coil 205 of the electromagnetic actuator 200 are connected to a drive circuit 300 that supplies the drive current to drive the electromagnetic actuator 200. The drive circuit 300 has a battery 301 as the supply source of the current and a switch 302 that switches whether the voltage (power supply voltage) of the battery 301 is applied to the coil 205. That is, the switch 302 switches the energization of the coil 205 to conduction or deactivation.

[0070] The control device 10 of the electromagnetic actuator 200 controls the drive current of the electromagnetic actuator 200, that is, the current supplied to the coil 205, by controlling the switch 302 of the drive circuit 300. Specifically, the control device 10 includes a power supply unit 11, a measurement unit 12, a switch detection unit 13, a switch state calculation unit 14, a switch state change detection unit 15, and an operation state detection unit 16.

[0071] The energizing unit 11 switches the energization of the coil 205, supplying a switching current to the coil 205 to maintain the current flowing through the coil 205 within a certain range. As described above, the drive current of the electromagnetic actuator 200 is roughly divided into peak current and holding current. Figure 9 As shown, the energizing part 11 switches the coil 205, and the holding current is supplied to the coil 205 as a switching current with an amplitude that changes periodically within a certain range.

[0072] The measuring unit 12 measures the switching current supplied to the coil 205 and outputs it to the energizing unit 11 and the switching detection unit 13. The energizing unit 11 controls the timing of switching on and off the energizing of the coil 205 based on the switching current measured by the measuring unit 12 and the preset upper and lower limits of the switching current.

[0073] The switch detection unit 13 detects the rise and fall of the switching current supplied to the coil 205. The rise in switching current refers to the increase or decrease in current through the conduction of electricity to the coil 205, such as... Figure 9 As in the T1 interval, the value of the switching current increases. The decrease in switching current refers to the reduction in current supplied to coil 205 by disconnecting the current. Figure 9 As in the T2 interval, the value of the switching current is reduced.

[0074] In Embodiment 1, the switch detection unit 13 detects an increase in switch current as a rise in switch current and a decrease in switch current as a fall in switch current.

[0075] Specifically, such as Figure 10 As shown, the switch detection unit 13 in Embodiment 1 can also be composed of a differentiating circuit 17 that differentiates the switching current output from the measuring unit 12, and a positive / negative determination circuit 18 that determines the positive or negative value of the output of the differentiating circuit 17. The differentiating circuit 17 can be composed of a known analog circuit using operational amplifiers, resistors, and capacitors as circuit components. The positive / negative determination circuit 18 can be composed of a known analog circuit such as a comparator circuit using operational amplifiers and resistors as circuit components. The outputs of the differentiating circuit 17 and the positive / negative determination circuit 18 are respectively... Figure 11 The output shown.

[0076] The switch state calculation unit 14 calculates the ratio (T1 / T2) between the rise time of the switch current detected by the switch detection unit 13 (hereinafter also referred to as "rise time T1") and the fall time of the switch current detected (hereinafter also referred to as "fall time T2").

[0077] In Embodiment 1, the switch state calculation unit 14 detects the time when the increase in switch current is detected as the rise time T1 and the time when the decrease in switch current is detected as the fall time T2. The switch state calculation unit 14 of Embodiment 1 calculates the ratio (T1 / T2) between the time when the increase in switch current is detected and the time when the decrease in switch current is detected.

[0078] Specifically, such as Figure 10 As shown, the switch state calculation unit 14 in Embodiment 1 can also be composed of a smoothing circuit 19 that smooths the output of the positive / negative determination circuit 18. The smoothing circuit 19 can be composed of a known analog circuit, such as a filter circuit using resistors and capacitors as circuit components. The output of the smoothing circuit 19 becomes... Figure 11 The output shown. Figure 11 The vertical axis of the output of the smoothing circuit 19 shown represents the ratio (T1 / T2).

[0079] The switch state change detection unit 15 detects changes in the ratio (T1 / T2) calculated by the switch state calculation unit 14. Specifically, as follows... Figure 10 As shown, the switch state change detection unit 15 can also be configured as an inflection point extraction circuit 20 that extracts the inflection point of the output of the smoothing circuit 19. The inflection point extraction circuit 20 can be configured as a known analog circuit consisting of two differentiating circuits connected in series. The output of the inflection point extraction circuit 20 is the result of the second-order derivative of the input. The output of the inflection point extraction circuit 20 is... Figure 11 The output shown.

[0080] The operation state detection unit 16 detects the operation state of the movable member 204 based on the change in the ratio (T1 / T2) detected by the switch state change detection unit 15. Specifically, the operation state detection unit 16 detects the moment when the detected ratio (T1 / T2) changes as the moment when the movable member 204 operates, i.e., the valve closing end time Tb. More specifically, in Embodiment 1, the operation state detection unit 16 searches for the peak value of the second derivative of the ratio (T1 / T2) output by the inflection point extraction circuit 20, and detects the moment when the searched peak value occurs as the valve closing end time Tb. The moment when the searched peak value occurs represents the moment when the inflection point extracted by the inflection point extraction circuit 20 occurs, and represents the moment when the ratio (T1 / T2) changes.

[0081] In addition, the second derivative of the input signal has the characteristic of emphasizing the noise of the signal, and methods of second derivative without emphasizing noise are described in the following literature.

[0082] •IFAC-PapersOnLine 51(31):35-40, DOI: 10.1016 / j.ifacol.2018.10.007, or

[0083] ・"Decrease of Minimum Injection Fuel Mass on The Basis of The Micro-sec-level Production Error Detection".

[0084] The inventors have studied the characteristics of the switching current supplied to coil 205 using various power supply voltages to accurately detect the valve closing time Tb. As a result, the inventors discovered that, as... Figure 9 As shown, regardless of the power supply voltage, the ratio (T1 / T2) of the rise time T1 to the fall time T2 of the switching current before the valve closing time Tb is greater than the ratio (T1 / T2) of the rise time T1 to the fall time T2 of the switching current after the valve closing time Tb. This is because, before the valve closing time Tb, the rise of the switching current slows down due to the back electromotive force generated by coil 205, and after the valve closing time Tb, this back electromotive force disappears. This is an event that occurs regardless of the power supply voltage. This means that the ratio (T1 / T2) of the rise time T1 to the fall time T2 of the switching current changes before and after the valve closing time Tb. Therefore, by detecting the change in the ratio (T1 / T2), the control device 10 can accurately detect the valve closing time Tb without relying on the power supply voltage.

[0085] As described above, the control device 10 of Embodiment 1 is a device for controlling an electromagnetic actuator 200, which has a stator 206, a coil 205 fixed on the stator 206, and a movable member 204 that operates based on the current supplied to the coil 205. The control device 10 includes: an energizing unit 11 that switches the energization of the coil 205 to supply a switching current to the coil 205; a switching detection unit 13 that detects the rise and fall of the switching current supplied to the coil 205; a switching state calculation unit 14 that calculates the ratio (T1 / T2) of the time when the rise is detected (T1) and the time when the fall is detected (T2); a switching state change detection unit 15 that detects the change in the calculated ratio (T1 / T2); and an operation state detection unit 16 that detects the operation state of the movable member 204 based on the detected change in the ratio (T1 / T2).

[0086] Therefore, even when the frequency of the switching current varies according to the power supply voltage, the control device 10 can accurately detect the operating state of the mover 204 without relying on the power supply voltage. Thus, the control device 10 can accurately detect the operating state of the movable part 204 of the electromagnetic actuator 200.

[0087] Furthermore, in the control device 10 of Embodiment 1, the switch detection unit 13 detects an increase in switch current as a rise in switch current and a decrease in switch current as a fall in switch current. The operation state detection unit 16 detects the moment when the detected ratio (T1 / T2) changes as the moment when the movable member 204 operates.

[0088] Therefore, the control device 10 can reliably detect the rise time T1 and fall time T2 of the switching current, and thus can reliably detect the moment when the ratio (T1 / T2) changes. Therefore, the control device 10 can accurately and reliably detect the moment when the movable element 204 actuates (valve closing time Tb) without relying on the power supply voltage. Therefore, the control device 10 can accurately and reliably detect the operating state of the movable element 204 of the electromagnetic actuator 200.

[0089] Furthermore, in the control device 10 of Embodiment 1, the switch detection unit 13 is composed of a differentiating circuit 17 that differentiates the switch current and a positive / negative determination circuit 18 that determines the positive or negative value of the output of the differentiating circuit 17. The switch state calculation unit 14 is composed of a smoothing circuit 19 that smooths the output of the positive / negative determination circuit 18. The switch state change detection unit 15 is composed of an inflection point extraction circuit 20 that extracts the inflection point of the output of the smoothing circuit 19. The operation state detection unit 16 detects the moment when the extracted inflection point occurs as the moment when the movable member 204 operates.

[0090] Therefore, the control device 10 can accurately detect the moment when the movable element 204 actuates (valve closing time Tb) by simply combining existing circuits. Thus, the control device 10 can accurately and easily detect the moment when the movable element 204 actuates (valve closing time Tb) without relying on the power supply voltage. Therefore, the control device 10 can accurately and easily detect the operating state of the movable element 204 of the electromagnetic actuator 200.

[0091] Alternatively, the measurement unit 12 can also sample the switching current supplied to the coil 205 to obtain a measured value of the switching current. Specifically, the measurement unit 12 can also sample the switching current with a sampling period shorter than the switching period of the energizing unit 11. The measurement unit 12 can also perform AD conversion on the switching current for each sample to obtain a measured value of the switching current.

[0092] The switch detection unit 13 can also compare the measured value I_(t) of the switch current acquired by the measurement unit 12 with the previously acquired measured value I_(t-1). The measurement unit 12 performs an increase / decrease determination of the switch current for each sampling and outputs a determination value representing the result of this determination. For example, if the measured value I_(t) of the switch current acquired this time is greater than the previously acquired measured value I_(t-1), the switch detection unit 13 can determine that the switch current has increased and output a determination value a(t) = 1; otherwise, it can determine that the switch current has decreased and output a determination value a(t) = -1.

[0093] The switch state calculation unit 14 can also calculate the average value b(t) of the judgment value a(t) output from the switch detection unit 13 over a predetermined time longer than the switching cycle of the energizing unit 11, and calculate the ratio (T1 / T2) based on the calculated average value b(t). The average value b(t) can be, for example, the value obtained by averaging the judgment values ​​a(t), a(t-1), ..., a(t-(N-1)) output in each sample from the current sample to the backtracking (N-1)th sample.

[0094] The switch state change detection unit 15 can also detect the change in ratio (T1 / T2) by performing a second-order differential on the average value b(t) calculated by the switch state calculation unit 14.

[0095] Therefore, the control device 10 can accurately and easily detect the moment when the movable element 204 actuates (valve closing time Tb) using software, without relying on the power supply voltage. Thus, the control device 10 can accurately and easily detect the operating state of the movable element 204 of the electromagnetic actuator 200.

[0096] [Implementation Method 2]

[0097] In Embodiment 1, the switch detection unit 13 detects the rise and fall of the current based on the increase or decrease of the switch current. However, in Embodiment 2, the switch detection unit 13 detects the rise and fall of the current based on the voltage between the terminals of the coil 205.

[0098] use Figure 12 and Figure 13 The control device 10 of the electromagnetic actuator 200 in Embodiment 2 will be described. In the control device 10 of Embodiment 2, the same configuration and operation as in Embodiment 1 will be omitted from the description.

[0099] Figure 12 This diagram illustrates the specific configuration of the switch detection unit 13, the switch state calculation unit 14, and the switch state change detection unit 15 in Embodiment 2. Figure 13 This is an explanation Figure 12The diagram shows the outputs of the power-on detection circuit 21, the smoothing circuit 19, and the inflection point extraction circuit 20.

[0100] In Embodiment 2, the switch detection unit 13 detects an increase in switch current when a voltage is applied between the terminals of the coil 205, and a decrease in switch current when no voltage is applied between the terminals of the coil 205. Similarly to Embodiment 1, the operation state detection unit 16 in Embodiment 2 detects the moment when the ratio (T1 / T2) detected by the switch state change detection unit 15 changes, which is taken as the moment when the movable member 204 operates, i.e., the valve closing time Tb.

[0101] Therefore, the control device 10 of Embodiment 2 can easily detect the rise time T1 and fall time T2 of the switching current based on the operation of the energized part 11, and thus can easily detect the moment when the ratio (T1 / T2) changes compared to Embodiment 1. Therefore, the control device 10 of Embodiment 2 can more easily detect the moment when the movable member 204 operates (valve closing end time Tb) than in Embodiment 1. Therefore, the control device 10 of Embodiment 2 can accurately and easily detect the operating state of the movable member 204 of the electromagnetic actuator 200.

[0102] Specifically, such as Figure 12 As shown, the switch detection unit 13 in Embodiment 2 can also be composed of a power-on detection circuit 21, which determines the conduction time when the energized unit 11 applies voltage between the terminals of the coil 205 and the disconnection time when the energized unit 11 does not apply voltage between the terminals of the coil 205. The output of the power-on detection circuit 21 becomes... Figure 13 The output shown.

[0103] like Figure 12 As shown, the switch state calculation unit 14 in Embodiment 2 can also be configured as a smoothing circuit 19 that smooths the output of the power-on detection circuit 21. Similar to Embodiment 1, the switch state change detection unit 15 in Embodiment 2 can also be configured as an inflection point extraction circuit 20 that extracts the inflection points of the output of the smoothing circuit 19. The outputs of the smoothing circuit 19 and the inflection point extraction circuit 20 in Embodiment 2 are the same as in Embodiment 1, becoming... Figure 13 The output shown.

[0104] Similar to Embodiment 1, the operation state detection unit 16 in Embodiment 2 detects the moment when the ratio (T1 / T2) changes, as detected by the switch state change detection unit 15, as the moment when the movable member 204 operates, i.e., the valve closing end time Tb. Specifically, similar to Embodiment 1, the operation state detection unit 16 in Embodiment 2 detects the moment when the inflection point extracted by the inflection point extraction circuit 20 is generated as the valve closing end time Tb.

[0105] Therefore, the control device 10 of Embodiment 2, like that of Embodiment 1, can accurately detect the moment when the movable member 204 operates (valve closing end time Tb) simply by constructing a simple existing circuit using a combination circuit. Therefore, the control device 10 of Embodiment 2, like that of Embodiment 1, can accurately and easily detect the moment when the movable member 204 operates (valve closing end time Tb) without relying on the power supply voltage. Therefore, the control device 10, like that of Embodiment 1, can accurately and easily detect the operating state of the movable member 204 of the electromagnetic actuator 200.

[0106] Furthermore, the present invention is not limited to the embodiments described above, but includes various modifications. For example, the embodiments described above are detailed embodiments provided for ease of understanding and explanation of the present invention, and are not necessarily limited to embodiments possessing all the described configurations. Additionally, the configurations of other embodiments may replace a portion of the configurations of certain embodiments, and the configurations of other embodiments may be added to the configurations of certain embodiments. Furthermore, for a portion of the configuration of each embodiment, other configurations may be added, deleted, or substituted.

[0107] Furthermore, some or all of the aforementioned components, functions, processing units, and processing modules can be implemented in hardware, for example, by designing using integrated circuits. Alternatively, the aforementioned components and functions can be implemented in software by a processor interpreting and executing programs that perform their respective functions. The programs implementing these functions, magnetic tapes, files, and other information can be stored in recording devices such as memory, hard disks, SSDs (solid-state drives), or recording media such as IC cards, SD cards, and DVDs.

[0108] Furthermore, control lines and information lines refer to lines deemed necessary in the specifications, but not all control lines and information lines may be represented on the product. In reality, almost all components can be considered interconnected.

[0109] Explanation of symbols

[0110] 10…Control device, 11…Electrification unit, 12…Measuring unit, 13…Switch detection unit, 14…Switch state calculation unit, 15…Switch state change detection unit, 16…Action state detection unit, 17…Differential circuit, 18…Positive / negative determination circuit, 19…Smoothing circuit, 20…Inflection point extraction circuit, 21…Electrification detection circuit, 200…Electromagnetic actuator, 204…Moving part, 205…Coil, 206…Stator.

Claims

1. A control device of an electromagnetic actuator that controls an electromagnetic actuator having a stator, a coil fixed to the stator, and a movable member that acts based on a current supplied to the coil, characterized by comprising: an energization section that supplies an on-off current to the coil by switching the energization to the coil; an on-off detection section that detects an increase and a decrease in the on-off current supplied to the coil; an on-off state calculation section that calculates a ratio of a time at which the increase is detected to a time at which the decrease is detected; an on-off state change detection section that detects a change in the calculated ratio; and an operation state detection section that detects an operation state of the movable member based on the detected change in the ratio.

2. The control device of an electromagnetic actuator according to claim 1, characterized in that the on-off detection section detects an increase in the on-off current as the increase and a decrease in the on-off current as the decrease, and the operation state detection section detects a time at which the detected ratio changes as a time at which the movable member operates.

3. The control device of an electromagnetic actuator according to claim 1, characterized in that the on-off detection section detects an application of a voltage between terminals of the coil as the increase and a non-application of the voltage between the terminals of the coil as the decrease, and the operation state detection section detects a time at which the detected ratio changes as a time at which the movable member operates.

4. The control device of an electromagnetic actuator according to claim 2, characterized in that the on-off detection section is composed of a differentiation circuit that differentiates the on-off current and a positive-negative determination circuit that determines a positive or negative of an output of the differentiation circuit, the on-off state calculation section is composed of a smoothing circuit that smoothes the output of the positive-negative determination circuit, the on-off state change detection section is composed of an inflection point extraction circuit that extracts an inflection point of an output of the smoothing circuit, and the operation state detection section detects a time at which the extracted inflection point occurs as a time at which the movable member operates.

5. The control device of an electromagnetic actuator according to claim 3, characterized in that the on-off detection section is composed of an energization detection circuit that discriminates an on time at which the energization section applies a voltage between terminals of the coil and an off time at which the energization section does not apply the voltage between the terminals of the coil, the on-off state calculation section is composed of a smoothing circuit that smoothes an output of the energization detection circuit, the on-off state change detection section is composed of an inflection point extraction circuit that extracts an inflection point of an output of the smoothing circuit, and the operation state detection section detects a time at which the extracted inflection point occurs as a time at which the movable member operates.

6. The control device of an electromagnetic actuator according to claim 2, characterized in that ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Further provided is a measurement unit that acquires a measurement value of the switching current by sampling the switching current at a sampling period shorter than a switching period of the energization unit, The switching detection unit compares the measurement value acquired this time with the measurement value acquired last time, and the measurement unit performs an increase / decrease determination of the switching current every sampling, and outputs a determination value indicating the increase / decrease determination result, The switching state calculation unit calculates an average value of the determination value outputted averaged over a predetermined time longer than the switching period of the energization unit, and calculates the ratio based on the calculated average value.

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