Simulation method, simulation apparatus, program, and recording medium

Abstract

This invention provides a simulation method, simulation apparatus, program, and recording medium capable of simulating the boost voltage of an injector drive device without using an equivalent circuit model. [Solution] A simulation method for simulating the boosted voltage supplied to a drive circuit that supplies drive current to an injector, wherein the boosted voltage is simulated based on an injector control model and a mathematical model.

Description

[Technical Field]

[0001] This invention relates to a simulation method, a simulation apparatus, a program, and a recording medium. [Background technology]

[0002] Patent Document 1 below discloses an equivalent circuit for a coil, a circuit simulator, and a method for creating a circuit simulator that can analyze electrical equipment such as electric motors that include coils, eliminate the need for iterative calculations when dealing with nonlinear characteristic data for coils, and enable practical modeling by treating the inductance component value as a variable value. The background technology involves configuring electrical equipment as an equivalent circuit model of a coil and simulating the behavior of electrical equipment by incorporating this equivalent circuit model into a circuit simulator. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-195608 [Overview of the project] [Problems that the invention aims to solve]

[0004] Incidentally, the background technology described above requires the creation of equivalent circuit models for electrical equipment that uses coils as loads, making the pre-analysis work complicated. For example, an injector drive unit for an internal combustion engine, which is a form of electrical equipment that uses coils as components and has an injector that acts as a valve body via the coil, a drive circuit connected to the injector, and a boost circuit connected to the input side of the drive circuit, is composed of various elements other than the coil of the injector that acts as the load, such as switching transistors in the drive circuit and boost circuit, and capacitors in the boost circuit. Creating an equivalent circuit model consisting of all these elements for the voltage supplied from the boost circuit to the drive circuit (boosted voltage), and then simulating its operation by incorporating the equivalent circuit model into a circuit simulator, requires a great deal of simulation effort.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a simulation method, simulation apparatus, program, and recording medium that can simulate the boosted voltage of an injector drive device without using an equivalent circuit model. [Means for solving the problem]

[0006] To achieve the above objective, the present invention provides a simulation method for simulating the boosted voltage of a boost circuit in an injector drive device having a drive circuit connected to an injector and a boost circuit connected to the input side of the drive circuit, wherein the simulation method counts the passage of time and sets the on / off state of the function of charging the capacitor of the boost circuit based on the boosted voltage calculated while setting the time at which injection start control using the boosted voltage to open the injector valve is started, the time at which injection start control is stopped, the time at which further injection start control using the boosted voltage is started at a predetermined time interval from the time at which injection start control is stopped, and the time at which further injection start control is stopped, according to a predetermined control input value, and the injector drive device has a drive circuit connected to an injector and a boost circuit connected to the input side of the drive circuit, and sets the on / off state of the function of charging the capacitor of the boost circuit, The system comprises an injector control model, a first mathematical model applied to the calculation of the boosted voltage in the interval from the voltage value at the time of initiating injection rise control until the boosted voltage drops to a predetermined threshold when the function of charging the capacitor of the boost circuit is off, a second mathematical model applied to the calculation of the boosted voltage in the interval from the time of initiating injection rise control until the injection rise control is stopped when the function of charging the capacitor of the boost circuit is on, and a third mathematical model applied to the calculation of the boosted voltage in the interval when the injection rise control is stopped when the function of charging the capacitor of the boost circuit is on, and is characterized in that time-series data of the boosted voltage is created based on the injector control model and the mathematical models. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a simulation method, simulation apparatus, simulation program, and recording medium that can simulate the boosted voltage of a drive device without using an equivalent circuit model. Therefore, according to the present invention, it is possible to contribute to reducing the simulation man-hours and simulation preparation man-hours. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing the configuration of a simulation device related to one embodiment of the present invention. [Figure 2] This is a block diagram (a) showing the configuration of the injector drive device in one embodiment of the present invention, and a waveform diagram (b) showing its operation. [Figure 3] This is a schematic diagram showing the mathematical model of a boost circuit in one embodiment of the present invention. [Figure 4] This is a flowchart showing a simulation method according to one embodiment of the present invention. [Figure 5] Figure 4 is a subroutine flowchart showing the processing of steps S4 to S11 of the simulation method. [Figure 6] Figure 4 is a subroutine flowchart showing the processing of steps S13 to S18 of the simulation method. [Figure 7] Figure 4 is a subroutine flowchart showing the processing of steps S19 to S26 of the simulation method. [Figure 8] This is the first schematic diagram illustrating a simulation method relating to one embodiment of the present invention. [Figure 9] This is a second schematic diagram illustrating a simulation method relating to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] One embodiment of the present invention will be described below with reference to the drawings. As shown in Figure 1, the simulation device A according to this embodiment is a device that simulates (simulates) the operation of an injector drive device W (see Figure 2(a)) by reading a simulation program C recorded on the recording medium B from the recording medium B.

[0010] In other words, simulation device A is a type of computer that executes simulation program C as an application program. As shown in Figure 1, simulation device A comprises at least a reading unit 1, an arithmetic unit 2, a storage unit 3, an operation unit 4, and a display unit 5.

[0011] Here, the recording medium B is not particularly limited in form as long as it has the function of storing the simulation program C. Examples of the recording medium B include an optical disk that optically stores / reads the simulation program C, a magnetic storage device such as a hard disk that magnetically stores / reads the simulation program C, or various semiconductor memories. For example, a data server located remotely from the simulation device A is also included in the recording medium B.

[0012] The reading unit 1 acquires the simulation program C from such a recording medium B and outputs it to the calculation unit 2. That is, when the recording medium B is an optical disk, the reading unit 1 optically reads the simulation program C from the recording medium B. When the recording medium B is a magnetic storage device, the reading unit 1 magnetically reads the simulation program C from the recording medium B. When the recording medium B is a semiconductor memory, the reading unit 1 electrically reads the simulation program C from the recording medium B. When the recording medium B is a data server, the reading unit 1 acquires the simulation program C via a communication medium that temporarily transmits the simulation program C as an electrical signal or radio wave.

[0013] The calculation unit 2 stores (saves) the simulation program C input from the reading unit 1 in the storage unit 3. The calculation unit 2 also reads and executes the simulation program C from the storage unit 3 based on an operation instruction input from the operation unit 4. That is, the calculation unit 2 simulates the boosted voltage based on the simulation program C, creates time-series data indicating the time-series change of the boosted voltage based on the result of the simulation, and outputs, for example, this time-series data to the display unit 5 as a video signal.

[0014] The storage unit 3 is a storage device such as a semiconductor memory or / and a hard disk. This storage unit 3 stores the simulation program C input from the arithmetic unit 2, and reads out the simulation program C based on the read command input from the arithmetic unit 2 and outputs it to the arithmetic unit 2. Further, the storage unit 3 stores the time-series data of the boosted voltage input from the arithmetic unit 2 in a readable manner.

[0015] Also, in this embodiment, the storage unit 3 stores in advance information regarding the injector driving device W as simulation target information. Although details will be described later, this simulation target information is a control model, a mathematical model, etc. of the injector driving device W. Note that this simulation target information may be incorporated in advance in the simulation program C.

[0016] The operation unit 4 is an input device that receives operation instructions from an operator, and is, for example, a pointing device such as a keyboard or / and a mouse. When this operation unit 4 receives an operation instruction from an operator, it generates an operation signal corresponding to the operation instruction and outputs it to the arithmetic unit 2.

[0017] The display unit 5 displays the simulation result of the injector driving device W on the screen based on the video signal input from the arithmetic unit 2. Such a display unit 5 is a liquid crystal display device that is common as a display device for various computers.

[0018] Subsequently, the injector driving device W in this embodiment, that is, the simulation target of the simulation device A according to this embodiment, will be described with reference to FIG. 2.

[0019] This injector driving device W is provided in a vehicle equipped with an engine. That is, this injector driving device W is a driving device that drives the injector L (load) by supplying a driving current.

[0020] An injector L is an inductive load that displaces (changes state) the valve body to an open position (open state) or a closed position (closed state) when a drive current is passed through the coil. Such an injector L is a fuel injection control valve that intermittently opens to inject a predetermined amount of fuel into the vehicle's engine moment by moment.

[0021] As shown in Figure 2(a), the injector drive unit W comprises a battery w1, a boost circuit w2, and a drive circuit w3. The battery w1 outputs battery power (DC power) of a predetermined voltage to the boost circuit w2 and the drive circuit w3. This battery w1 is, for example, a rechargeable lead-acid battery installed in the vehicle, and supplies DC power of, for example, 12V (volts) as battery power to the boost circuit w2 and the drive circuit w3.

[0022] The boost circuit w2 receives battery power as primary power and outputs the boosted piezoelectric force obtained by boosting the battery power at a predetermined boost ratio as secondary power to the drive circuit w3. This boost circuit w2 is a well-known type of chopper circuit and includes a shunt resistor 1a, a boost coil 1b, a main switch 1c, a synchronous switch 1d, a smoothing capacitor 1e, a voltage detection unit 3b that detects the voltage on the secondary side of the boost circuit w2 (the voltage on the primary side of the drive circuit w3), a boost control unit 3c that controls the charging of the smoothing capacitor 1e according to the voltage on the secondary side of the boost circuit w2, and a drive control unit 3d that controls the drive voltage applied to the injector L by the drive circuit w3.

[0023] One end of the shunt resistor 1a is connected to the input terminal of the injector drive unit W, and the other end is connected to one end of the boost coil 1b. This shunt resistor 1a is a low-resistance resistor with a relatively small resistance value, and generates a voltage drop corresponding to the current passing through the battery power.

[0024] The boost coil 1b has one end connected to the other end of the shunt resistor 1a, and the other end connected to the input terminal of the main switch 1c and the input terminal of the synchronous switch 1d. When the main switch 1c is turned ON (conducting), a current (inductor current) due to the battery power flows through the boost coil 1b, and when the main switch 1c switches from the ON state to the OFF state (non-conducting state), it generates electromagnetic energy due to the change in the decay of the inductor current.

[0025] The voltage detection unit 3b has its input terminal connected to the output terminal of the boost circuit w2 and the input terminal of the drive circuit w3. This voltage detection unit 3b detects the output voltage of the boost circuit w2 as a boosted voltage and outputs it to the boost control unit 3c.

[0026] The main switch 1c has its input terminal connected to the other end of the boost coil 1b and the input terminal of the synchronous switch 1d, its output terminal grounded to GND which is the reference potential, and its control terminal connected to a boost control unit equipped with a microcomputer. This main switch 1c is an electronic switch that switches between an ON state (conducting state) and an OFF state (non-conducting state) by a first boost control signal input from the boost control unit, and operates ON / OFF (intermittently) when generating electromagnetic energy in the boost coil 1b. As shown in the figure, such a main switch 1c is, for example, a MOS-FET (MOS field-effect transistor).

[0027] In this embodiment, the boost control unit 3c simulated sets a first boost control signal so as to turn off the main switch 1c when the secondary voltage of the boost circuit w2 exceeds a first voltage value V0 described later, preventing electromagnetic energy from being generated in the boost coil 1b, and once the secondary voltage of the boost circuit w2 exceeds a predetermined threshold value V0 described later, the boost control signal is set to turn off the main switch 1c. R The system is configured to set the first boost control signal so that it enters an ON / OFF (intermittent) operation state, generating electromagnetic energy in the boost coil 1b. In this way, hysteresis is provided to the operating state of the main switch 1c, which the boost control unit uses to store electromagnetic energy in the boost coil 1b.

[0028] The synchronous switch 1d has its input terminal connected to the other end of the boost coil 1b and the input terminal of the main switch 1c, its output terminal connected to one end of the smoothing capacitor 1e and the input terminal of the drive circuit w3, and its control terminal connected to the boost control unit 3c. This synchronous switch 1d is a sub-switch that turns on / off in the opposite phase to the main switch 1c and is controlled by a second boost control signal input from the boost control unit 3c. Such a synchronous switch 1d is, like the main switch 1c described above, for example, a MOS-FET (MOS field-effect transistor). Note that the intermittent timing of the main switch 1c and the intermittent timing of the synchronous switch 1d are slightly offset to prevent shoot-through current.

[0029] The smoothing capacitor 1e has one end connected to the input terminals of the synchronous switch 1d and the drive circuit w3, and the other end connected to GND, which is the reference potential. One end of such a smoothing capacitor 1e corresponds to the output terminal of the boost circuit w2.

[0030] In other words, the boost circuit w2 supplies intermittent power obtained by switching the battery power to the boost coil 1b, and generates boosted power by storing the increased current generated in the boost coil 1b by this supply of intermittent power in the smoothing capacitor 1e. The boost ratio is, for example, about 2 to 3, and the boost circuit w2 outputs a boosted voltage, obtained by boosting the 12V (volt) battery power to a voltage of about 24 to 66V (volts), to the drive circuit w3.

[0031] The drive circuit w3 accepts boosted power and battery power to set the drive voltage applied to the injector L, and outputs a drive current to the injector L corresponding to the drive voltage. Of the pair of input terminals of this drive circuit w3, one is connected to the output terminal of the boost circuit w2, and the other is connected to the input terminal of the injector drive device W. The output terminal of this drive circuit w3 is also connected to one end of the injector L. Of the pair of control input terminals of the drive circuit w3, one control input terminal is connected to the drive control unit 3d, and the other control input terminal (not shown) is connected to the control unit 3 of an internal combustion engine (not shown). Such a drive circuit w3 is equipped with a plurality of on / off switches (not shown) controlled by a PWM (Pulse Width Modulation) signal input from the drive control unit 3d to the one control input terminal, and controls the plurality of on / off switches by duty cycle control that selectively selects between boosted power and battery power (non-boosted power) to set the drive voltage applied to the injector L. Furthermore, the drive circuit w3 includes a plurality of on / off switches (not shown) controlled by an injector control signal input to the other control input terminal, and supplies a drive current to one end of the injector L at a desired on / off valve timing set by the control unit 3 of the internal combustion engine. Based on this drive current, the injector L changes its state from closed to open.

[0032] The drive voltage changes according to the duty cycle in the PWM signal described above. In this embodiment, the drive voltage becomes closer to the boosted power as the duty cycle increases, and closer to the battery power as the duty cycle decreases. During the injection rise period in which the injector L changes from a closed state to an open state, the drive control unit 3d sets the duty cycle to a relatively large value and sets the drive voltage to a value close to the boosted power. After the desired injection rise period set by the control unit of the internal combustion engine has passed and the injector L reaches the open state, the drive control unit 3d sets the duty cycle to a relatively small value and sets the drive voltage to a value close to the battery power to maintain the open state.

[0033] In other words, during the initial rise period when the injector L changes state from closed to open, a relatively large drive current based on boosted power is supplied to the injector L. This relatively large drive current is the opening current that speeds up the opening of the injector L during the injection rise period. Then, during the holding period after the injection rise period, a smaller drive current is supplied to the injector L than during the injection rise period. This smaller drive current is the holding current that maintains the open state of the injector L at a nearly constant level.

[0034] Such an injector drive device W has characteristics of boosted voltage (input to drive circuit w3) and drive current (output to drive circuit w3) as shown in Figure 2(b), for example. That is, the drive current gradually increases over time during the injection rise period, reaching a peak current at the end of the injection rise period, and then gradually decreases to become the hold current during the subsequent hold period. On the other hand, the boosted voltage gradually decreases from the initial voltage (first voltage value V0) over time during the injection rise period as the smoothing capacitor 1e of the boost circuit w2 of the power supply discharges, reaching a minimum voltage at the end of the injection rise period, and then gradually increases back to the initial voltage during the subsequent hold period.

[0035] Here, the simulation target information stored in the simulation device A according to this embodiment includes a first voltage value V0, which is the value of the boost voltage V at which the charging function of the smoothing capacitor 1e of the boost circuit w2, a component of the injector drive device W, is stopped (turned off), and a predetermined threshold value V0, which is the value of the boost voltage V at which the charging function of the smoothing capacitor 1e of the boost circuit w2 is started (turned on). R The system includes a control model for an internal combustion engine that defines the start and end times of the injection rise period based on predetermined control input values, such as the injection start time and injection rise period, which will be described later. The simulation target information also includes the battery voltage of the battery w1, a component of the injector drive unit W, as a characteristic value.

[0036] Furthermore, the simulation target information includes three mathematical models, namely the first to third mathematical models, relating to the boost circuit w2, which is a component of the injector drive unit W. In other words, the mathematical model of the boost circuit w2 comprises the first to third mathematical models, corresponding to the three intervals, namely the first to third intervals, shown in Figure 3.

[0037] The first mathematical model states that when the function to charge the capacitor of the boost circuit is off, the boosted voltage is a predetermined threshold V from a first voltage value V0 at the time when injection rise control is started, which is also the time when power is supplied to the injector L. R This shows the boosted voltage V in the first section until the voltage drops to a certain level. Such a first mathematical model is represented by the following equations (1) and (2). Note that the first mathematical model can be applied, for example, to the calculation of the boosted voltage V in the first section shown in Figure 3.

[0038]

number

[0039]

number

[0040] In equation (1), "V" is the boost voltage, "V0" is the initial value of the boost voltage, and "C" is the capacitance of the smoothing capacitor 1e of the boost circuit w2. Also, in equation (1), "Q" is the amount of charge released to the outside of the smoothing capacitor 1e by discharge, and is expressed by equation (2). In equation (2), "I" is the drive current, and "I - ' is the drive current calculated in the previous time step in the simulation, and Δt is the time step.

[0041] Furthermore, the second mathematical model represents the boosted voltage in the second section, from the end of the first section until the discharge of the smoothing capacitor 1e of the boost circuit w2 stops. This second mathematical model is expressed by the following equation (3). In equation (3), "ΔV" is the voltage of the charge in the smoothing capacitor 1e. Note that the second mathematical model can be applied, for example, to the calculation of the boosted voltage V in the second section shown in Figure 3.

[0042]

number

[0043] Furthermore, the third mathematical model is applied to the calculation of the boosted voltage in the section where the injection rise control is stopped, when the function to charge the capacitor of the boost circuit is turned on. Such a third mathematical model is expressed by the following equations (4), (5), and (6). In equation (4), "V - This value represents the point at which the decrease in the boosted voltage stops. The third mathematical model is applied, for example, to the calculation of the boosted voltage V in the third interval shown in Figure 3.

[0044]

number

[0045] The charging voltage ΔV represents the increase in the boosted voltage V using a two-stage approximation curve. In the section where the voltage difference from the initial value V0 is large, the charging voltage ΔV changes linearly and hardly changes, so the boosted voltage V can be approximated by equation (5) below. Also, in the section where the voltage difference from the initial value V0 is small, the charging voltage ΔV gradually decreases, so the boosted voltage V can be approximated by equation (6) below.

[0046]

number

[0047]

number

[0048] In equation (6), α, β, γ, and ε are approximation coefficients. These approximation coefficients α, β, γ, and ε vary depending on the electrical characteristics of the boost circuit, and are, for example, the following values. α=4080, β=19914, γ=23016, ε=1212

[0049] Next, the operation of the simulation device A according to this embodiment, that is, the simulation method based on the simulation program C according to this embodiment, will be explained with reference to the flowcharts shown in Figures 4 to 7 and the schematic diagram in Figure 8. In Figure 8, for convenience, the first mathematical model is denoted as "Model 1," the second mathematical model as "Model 2," and the third mathematical model as "Model 3."

[0050] In the simulation method according to this embodiment, the boosted voltage V, which is the input to the drive circuit w3, is simulated by using the simulation target information, including the first to third mathematical models described above. Then, in this simulation method, time-series data of the boosted voltage V is created as the final simulation result.

[0051] In other words, in the simulation method according to this embodiment, as shown in Figure 4, it is first determined whether the variable MODE is #0 or not (step S0). If MODE = #0, the current time T, which is an additive (count-up) timer, is reset to #0, which indicates the start of the injection rise period. The injection rise period, which is a subtractive (count-down) timer, is set to #injection rise period 1, which is a predetermined first injection rise period. The previous boost voltage Vpre and the boost voltage V are reset to #initial value V0, which is a predetermined initial voltage value. The flag F_1stINJ, which indicates that the rise period of the first fuel injection has started, is set to 1. In addition, the flags F_2ndINJ, F_3rdINJ, and F_4thINJ, which indicate that the rise periods of the second, third, and fourth fuel injection have started, are reset to #0, respectively. Then, MODE is made equal to #1 (step S1).

[0052] On the other hand, if MODE ≠ #0 in step S0, the initial setup of the parameters used in the simulation method according to this embodiment is complete, so a predetermined time step Δt is added to the current time T. In this embodiment, the value of the time step Δt is set to 5 microseconds in advance. Next, the predetermined time step Δt is subtracted from the value of the injection rise period. Also, the previous boosted voltage Vpre is made equal to the value of the boosted voltage V (step S2). Then, it is determined whether or not it is the injection rise period using the boost circuit. For example, it is checked whether or not the injection rise period is greater than #0 (step S3).

[0053] If the injection rise time > #0, proceed to step S4 shown in Figure 5, and the boosted voltage V reaches the threshold #V R Check whether the value is greater than or equal to the specified value. Boost voltage V > #V RIf so, proceed to step S5 to determine whether the variable MODE is greater than or equal to #2. If MODE < #2 in step S5, it indicates that the main switch 1c of the boost circuit w2 is in the OFF state and the first boost control signal is set so that no electromagnetic energy is generated in the boost coil 1b, so MODE is set to equal to #1. Then, using the first mathematical model described above, calculate the boost voltage Vpre, which is a candidate value for the boost voltage V corresponding to the current time T (step S6).

[0054] In step S4, the boosted voltage V is #V R If it is determined that the following conditions apply, or if MODE is determined to be #2 or higher in step S5, the process proceeds to step S7 to check whether the boosted voltage V is greater than the lower limit of the output voltage of the boost circuit, which is the #V lower limit. If the boosted voltage V > #V lower limit in step S7, the process proceeds to step S8, where MODE is set to equal to #2. Then, using the second mathematical model described above, the boosted voltage Vpre, which is a candidate value for the boosted voltage V corresponding to the current time T, is calculated (step S8). After the execution of step S6 or step S8, the process proceeds to step S9 to check whether the boosted voltage Vpre is greater than the #V lower limit.

[0055] In step S9, if the boosted voltage Vpre is greater than or equal to the lower limit of #V, the boosted voltage V is made equal to the boosted voltage Vpre (step S10). In step S9, if it is determined that the boosted voltage Vpre < the lower limit of #V, the process proceeds to step S11, where the boosted voltage V is made equal to the lower limit of #V. Furthermore, in this embodiment, MODE is made equal to #2.5 (step S11).

[0056] Furthermore, if it is determined in step S7 that the boosted voltage V is less than or equal to the lower limit of #V, the boosted voltage V is made equal to the lower limit of #V, and MODE is made equal to #2.5 (step S11). As a result, in this embodiment, the calculation processing of the first mathematical model or the second mathematical model described above when the boosted voltage V is less than or equal to the lower limit of #V can be omitted, thereby further reducing the calculation time required for the simulation method, i.e., the simulation man-hours.

[0057] In step S3 shown in Figure 4, if it is determined that the injection rise period is less than or equal to #0, the injection rise period using the boost circuit has ended, so the process proceeds to step S12 to determine whether or not the time for the second fuel injection has arrived. For example, it is checked whether the current time T is greater than or equal to the start time of the #2nd injection, which is the start of the second injection rise period (step S12). If the current time T < #2nd injection start time, it indicates that the start time for the second fuel injection has not yet arrived, so the process proceeds to step S13 shown in Figure 6 to check whether or not MODE is less than #2. If MODE < #2, the boost voltage V is not calculated, and therefore, the value of the boost voltage V from the previous control cycle is retained, and the process proceeds to step S27, which will be described later.

[0058] If it is determined in step S13 that MODE is #2 or higher, the process proceeds to step S14 to check whether the boosted voltage V is smaller than the initial value V0. If the boosted voltage V < initial value V0 in step S14, it indicates that the main switch 1c of the boost circuit w2 is in an ON / OFF state, generating electromagnetic energy in the boost coil 1b. Therefore, using the third mathematical model described above, the boosted voltage Vpre, which is a candidate value for the boosted voltage V corresponding to the current time T, is calculated (step S15).

[0059] After step S15 is executed, the process proceeds to step S16, where it is checked whether the boosted voltage Vpre is less than the initial value V0. In step S16, if boosted voltage Vpre < initial value V0, the boosted voltage V is made equal to the boosted voltage Vpre, and MODE is made equal to #3 (step S17). In step S16, if boosted voltage Vpre is greater than or equal to the initial value V0, the boosted voltage V is made equal to the initial value V0, and MODE is made equal to #1 (step S18).

[0060] Furthermore, if it is determined in step S14 that the boosted voltage V is greater than or equal to the initial value V0, the process proceeds to step S18, and the boosted voltage V is set to equal to the initial value V0. This omits the calculation process of the third mathematical model described above when the boosted voltage V is greater than or equal to the initial value V0, thereby further reducing the simulation effort.

[0061] In step S12 shown in Figure 4, if it is determined that the current time T is equal to or greater than the #2nd injection start time, it means that the time for the second fuel injection to start has arrived, so the process proceeds to step S19 shown in Figure 7, where it is determined whether the flag F_2ndINJ=1 (step S19). If F_2ndINJ=0, it indicates that the second fuel injection has not yet started, so the process proceeds to step S20, where the flag F_2ndINJ is set to equal 1. Then, the injection rise time is set to equal #injection rise time 2, which is the set value for the second fuel injection rise time (step S20). After step S20 is executed, the process returns to step S4, and the operations of steps S4 to S11 described above are executed.

[0062] If F_2ndINJ=1 in step S19, it is determined whether or not the time for the third fuel injection has arrived. For example, it is checked whether the current time T is greater than or equal to the start time of the third injection rise period (#3rd injection start time) (step S21). If the current time T < #3rd injection start time, it indicates that the start time for the third fuel injection has not yet arrived, so the process returns to step S13 and the operations of steps S13 to S18 described above are executed.

[0063] In step S21, if it is determined that the current time T is equal to or greater than the start time of the third injection, it is determined that the time for the third fuel injection to start has arrived, and the flag F_3rdINJ is checked to see if it is 1 or not (step S22). If F_3rdINJ is 0, it indicates that the third fuel injection has not yet started, so the process proceeds to step S23, and the flag F_3rdINJ is set to 1. Then, the injection rise time is set to equal to the set value for the rise time of the third fuel injection, which is #injection rise time 3 (step S23). After step S23 is executed, the process returns to step S4, and the operations of steps S4 to S11 described above are performed.

[0064] If F_3rdINJ=1 in step S22, it is determined whether the time for the fourth fuel injection has arrived. For example, it is checked whether the current time T is greater than or equal to the start time of the #4th injection, which is the start of the fourth injection rise period (step S24). If the current time T < #4th injection start time, it indicates that the start time for the fourth fuel injection has not yet arrived, so the process returns to step S13 and the operations of steps S13 to S18 described above are executed.

[0065] In step S24, if it is determined that the current time T is equal to or greater than the start time of the 4th injection, it is determined that the time for the 4th fuel injection to start has arrived, and the flag F_4thINJ is checked to see if it is 1 or not (step S25). If F_4thINJ is 0, it indicates that the 4th fuel injection has not yet started, so the process proceeds to step S26, and the flag F_4thINJ is set to 1. The injection rise time is then set to equal to the set value for the rise time of the 4th fuel injection, which is #injection rise time 4 (step S26). After step S26 is executed, the process returns to step S4, and the operations of steps S4 to S11 described above are performed. If F_4thINJ is 1 in step S25, the process returns to step S13, and the operations of steps S13 to S18 described above are performed.

[0066] Returning to FIG. 4, the value of the boosted voltage V calculated by the operations of steps S0 to S26 described above is sequentially stored in the recording unit 3 as a simulation result represented in the form of time series data associated with the current time T (step S27).

[0067] In the simulation method according to the present embodiment as described above, the time series characteristics of the actual boosted voltage V, that is, the operation pattern of the actual boosting circuit, can be simulated and reproduced. For example, as shown in FIG. 8(a), when the boosted voltage V is maintained at a value greater than the threshold #V R during the first injection rising period (when the injection rising period ends while remaining in the MODE = #1 state in the flowchart of FIG. 4), the function of charging the capacitor of the boosting circuit is turned off during the period from the end of the first injection rising period to the start of the second injection rising period. In this case, since the smoothing capacitor 1e of the boosting circuit w2 is not charged, the value of the boosted voltage V is held at a constant value during the period from the end of the first injection rising period to the start of the second injection rising period. However, the simulation method according to the present embodiment correctly reproduces the operation of the boosting circuit w2 in this way.

[0068] Also, for example, as shown in FIG. 8(b), when the boosted voltage V is below the threshold #V R during the first injection rising period (when the first injection rising period ends in the MODE = #2 state in the flowchart of FIG. 4), the function of charging the capacitor of the boosting circuit is turned on. In this case, since the smoothing capacitor 1e of the boosting circuit w2 is charged until the boosted voltage V reaches the initial value V0 during the period from the end of the first injection rising period to the start of the second injection rising period, the value of the boosted voltage V shows an upward trend until it reaches the initial value V0. However, after reaching the initial value V0, the function of charging the capacitor of the boosting circuit is turned off and the boosted voltage V becomes a constant value. The simulation method according to the present embodiment correctly reproduces the operation of the boosting circuit w2 in this way.

[0069] Also, for example, as shown in FIG. 8(c), when the boosted voltage V is at the threshold #V RAs described below, the smoothing capacitor 1e of the boost circuit w2 is charged. However, if the boosted voltage V does not reach its initial value V0 during the period leading up to the start of the second injection rise period (when the second injection rise period starts with MODE=#3 in the flowchart of Figure 4), the function to charge the capacitor of the boost circuit remains on as the second injection rise period begins. In this case, since the charging of the smoothing capacitor 1e of the boost circuit w2 is not stopped, the degree of decrease in the boosted voltage V during the second injection rise period is smaller than the degree of decrease in the boosted voltage V during the first injection rise period. The simulation method according to this embodiment correctly reproduces this operation of the boost circuit w2.

[0070] Figure 9 compares the simulation results of the boosted voltage V obtained by the simulation method according to this embodiment with the actual measured boosted voltage V and the simulation results using a conventional equivalent circuit model. As shown in the upper part of Figure 9, the actual measured boosted voltage V showed that the voltage recovery time from the end of the injection rise control (bottom peak) to the voltage at which the capacitor charging function turns off was 0.806 milliseconds.

[0071] Furthermore, as shown in the lower part of Figure 9, the voltage recovery time was 0.796 milliseconds in the simulation results using a conventional equivalent circuit model, whereas the voltage recovery time obtained by the method according to this embodiment was 0.800 milliseconds, as shown in the lower part of Figure 9. These results demonstrate that the simulation method according to this embodiment can simulate the transient characteristics of the boosted voltage V with good accuracy.

[0072] Furthermore, as shown in the lower part of Figure 9, the time-series data of the boosted voltage V simulated using the control model and mathematical model according to this embodiment shows good agreement with the time-series data of the boosted voltage V simulated using a conventional equivalent circuit model. These findings indicate that the simulation method according to this embodiment has a practical simulation accuracy equivalent to that of measurement results and simulation results using a conventional equivalent circuit model.

[0073] The simulation method according to this embodiment is a simulation method for an injector drive device having a drive circuit connected to an injector and a boost circuit connected to the input side of the drive circuit, which simulates the boosted voltage of the boost circuit, and counts the passage of time, and sets the time when injection start-up control using the boosted voltage to open the injector valve is started, the time when injection start-up control is stopped, the time when further injection start-up control using the boosted voltage is started at a predetermined time interval from the time when injection start-up control is stopped, and the time when further injection start-up control is stopped, according to a predetermined control input value, and based on the calculated boosted voltage, it determines the on / off state of the function of charging the capacitor of the boost circuit. The system includes a set injector control model, a first mathematical model applied to the calculation of the boosted voltage in the interval from the voltage value at the start of injection rise control until the boosted voltage drops to a predetermined threshold when the function to charge the capacitor of the boost circuit is off, a second mathematical model applied to the calculation of the boosted voltage in the interval from the start of injection rise control until injection rise control is stopped when the function to charge the capacitor of the boost circuit is on, and a third mathematical model applied to the calculation of the boosted voltage in the interval when injection rise control is stopped when the function to charge the capacitor of the boost circuit is on, and time-series data of the boosted voltage is created based on the control model and mathematical models.

[0074] According to this embodiment, it is possible to provide a simulation method that can simulate the boosted voltage of a boost circuit without using an equivalent circuit model of the injector drive device.

[0075] The simulation device A according to this embodiment is a simulation device for an injector drive device having a drive circuit connected to an injector and a boost circuit connected to the input side of the drive circuit, and simulates the boosted voltage of the boost circuit, and counts the passage of time and sets the on / off state of the function of charging the capacitor of the boost circuit based on the boosted voltage calculated while setting the time when injection start control using the boosted voltage to open the injector valve starts, the time when injection start control stops, the time when further injection start control using the boosted voltage starts at a predetermined time interval from the time when injection start control stops, and the time when further injection start control stops, according to a predetermined control input value, an injector control model and The system includes: a first mathematical model applied to the calculation of the boosted voltage in the interval from the voltage value at the start of injection rise control until the boosted voltage drops to a predetermined threshold when the function to charge the capacitor of the boost circuit is off; a second mathematical model applied to the calculation of the boosted voltage in the interval from the start of injection rise control until injection rise control is stopped when the function to charge the capacitor of the boost circuit is on; a third mathematical model applied to the calculation of the boosted voltage in the interval when injection rise control is stopped when the function to charge the capacitor of the boost circuit is on; a calculation unit that creates time-series data of the boosted voltage based on the control model and the mathematical model; and a storage unit that stores the control model, the mathematical model, and the time-series data of the boosted voltage.

[0076] According to this embodiment, it is possible to provide a simulation device A that can simulate the boosted voltage of a boost circuit without using an equivalent circuit model of an injector drive device.

[0077] Furthermore, the simulation program C according to this embodiment is installed in the simulation device A that simulates the boosted voltage, and causes the simulation device A to simulate the boosted voltage of the boost circuit based on a mathematical model.

[0078] According to this embodiment, it is possible to provide a simulation program C that can simulate the boosted voltage of a boost circuit without using an equivalent circuit model of the injector drive device.

[0079] Furthermore, the storage medium B according to this embodiment stores a simulation program C that simulates the boosted voltage of the boost circuit, and the simulation program C simulates the boosted voltage based on a mathematical model.

[0080] According to this embodiment, it is possible to provide a recording medium B that can be read by various computers a simulation program C that simulates the boosted voltage of a boost circuit based on a mathematical model.

[0081] The present invention is not limited to the embodiments described above, and for example, the following modifications are possible. In the above embodiment, the present invention was described in the case where it is applied to the simulation of an injector drive device W that performs four fuel injections and four injection start-up controls in one combustion cycle of an internal combustion engine, but the present invention is not limited thereto. For example, the present invention can also be applied to an injector drive device in which the number of fuel injections and injection start-up controls performed in one combustion cycle is an arbitrary natural number.

[0082] Furthermore, the above embodiment describes a case where a subtraction (countdown) timer is applied, in which #injection_startup_period_n (where n is a natural number) is set as an initial value for the injection startup period (step S1, step S20, step S23, or step S26), a time step Δt is subtracted from this injection startup period at each calculation cycle (step S2), and it is determined whether the injection startup period has ended by checking whether the injection startup period obtained by subtracting the time step Δt is greater than #0 (step S3). However, the present invention is not limited to this. For example, the present invention can also apply an addition (count-up) timer method, in which #0 indicating the start is set as an initial value for the injection startup period, a time step Δt is added to this injection startup period at each calculation cycle, and it is determined whether the injection startup period has ended by checking whether the injection startup period obtained by adding the time step Δt is greater than or equal to #injection_startup_period_n. [Explanation of Symbols]

[0083] A Simulation device B Recording media C simulation program L Injector W Injector Drive Unit w1 battery w2 Boost Circuit w3 drive circuit 1. Reading section 2 Arithmetic section 3 Storage section 4 Control section 5 Display section

Claims

1. A simulation method for simulating the boosted voltage of a boost circuit in an injector drive device having a drive circuit connected to an injector and a boost circuit connected to the input side of the drive circuit, An injector control model that counts the passage of time and sets the on / off state of the function of charging the capacitor of the boost circuit based on the boost voltage calculated while setting the time at which injection start control using the boost voltage to open the injector valve is started, the time at which the injection start control is stopped, the time at which further injection start control using the boost voltage is started at a predetermined time interval from the time at which the injection start control is stopped, and the time at which the further injection start control is stopped, according to a predetermined control input value, and When the function of charging the capacitor of the boost circuit is turned off, a first mathematical model is applied to the calculation of the boosted voltage in the interval from the voltage value at the time the injection start control is started until the boosted voltage drops to a predetermined threshold, When the function to charge the capacitor of the boost circuit is turned on, a second mathematical model is applied to the calculation of the boosted voltage in the section from the time the injection rise control is started until the injection rise control is stopped, The system includes a third mathematical model that is applied to the calculation of the boosted voltage in the section in which the injection start-up control is stopped, when the function of charging the capacitor of the boost circuit is turned on, A simulation method characterized by creating time-series data of the boosted voltage based on the injector control model and the mathematical model.

2. A simulation device for simulating the boosted voltage of an injector drive device having a drive circuit connected to an injector and a boost circuit connected to the input side of the drive circuit, An injector control model that counts the passage of time and sets the on / off state of the function of charging the capacitor of the boost circuit based on the boost voltage calculated while setting the time at which injection start control using the boost voltage to open the injector valve is started, the time at which the injection start control is stopped, the time at which further injection start control using the boost voltage is started at a predetermined time interval from the time at which the injection start control is stopped, and the time at which the further injection start control is stopped, according to a predetermined control input value, and When the function of charging the capacitor of the boost circuit is turned off, a first mathematical model is applied to the calculation of the boosted voltage in the interval from the voltage value at the time the injection start control is started until the boosted voltage drops to a predetermined threshold, When the function to charge the capacitor of the boost circuit is turned on, a second mathematical model is applied to the calculation of the boosted voltage in the section from the time the injection rise control is started until the injection rise control is stopped, When the function to charge the capacitor of the aforementioned boost circuit is turned on, A third mathematical model applied to the calculation of the boosted voltage in the section where the injection rise control is stopped, A calculation unit that creates time-series data of the boosted voltage based on the injector control model and the mathematical model, A simulation apparatus characterized by having a storage unit that stores the injector control model, the mathematical model, and time-series data of the boosted voltage.

3. A program for causing a computer to execute the simulation method described in claim 1.

4. A recording medium storing a program for causing a computer to execute the simulation method described in claim 1.

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