JP4776641B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device that controls a drive motor that drives a valve device that is applied to an internal combustion engine, and more particularly to a motor control device that has a function of determining an abnormality in drive control such as an exhaust gas recirculation control valve and a swirl control valve.

  If an excessive current is supplied to the drive motor that drives the valve device, a failure due to burning occurs. Therefore, it is necessary to protect the excessive current from being supplied. Patent Document 1 discloses an abnormality diagnosis device for a drive system that drives an AC motor that is applied to an electric vehicle, although it is not a drive motor for a valve device that is applied to an internal combustion engine. In this drive system, a DC current is converted into an AC current by an inverter and an AC motor is driven. In the abnormality diagnosis device, the DC current input to the inverter is monitored and the input DC current vibrates. Is determined to be abnormal.

JP-A-9-200901

  The device disclosed in Patent Document 1 requires a sensor for monitoring the input current, and there is a problem that the configuration is complicated and the cost is increased.

  Also, a method for monitoring the motor temperature by a temperature sensor is well known, but a temperature sensor for monitoring is newly required.

  The present invention has been made paying attention to the above-mentioned points, and can determine a drive control abnormality of a drive motor of a valve device applied to an internal combustion engine by a simpler method and prevent failure due to burning. An object is to provide a motor control device.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a motor control device for controlling a drive motor for driving a valve device applied to an internal combustion engine. Drive means (20, 27) for supplying a drive current to the power supply, abnormality determination means for determining a drive control abnormality of the drive motor based on the change amount (DDUT) of the duty ratio, and the drive motor by the abnormality determination means Limiting means for limiting the duty ratio when it is determined that there is an abnormality in the drive control, and the limiting means is a moving average value of the duty ratio (TAV) in the immediately preceding predetermined moving averaging time (TAV). The moving average value calculating means for calculating DTDAV) and the limit value (DTLMA) are set so as to decrease as the moving average value (DTDAV) increases. That a limit setting means, said limit so that the duty ratio is equal to or less than the limit value (DTLMA), said valve device, an exhaust gas recirculation control for controlling the amount of exhaust gas recirculated to the intake system from an exhaust system of the engine It includes at least one of a valve (26) and a swirl control valve (19) for controlling a swirl in the combustion chamber of the engine.

According to the first aspect of the present invention, a drive control signal having a variable duty ratio is input to the drive means, and a drive current is supplied from the drive means to the drive motor of the valve device. Based on the amount of change in the duty ratio of the drive control signal, the drive motor drive control abnormality is determined, and when it is determined that the motor drive control is abnormal, the duty ratio is limited. That is, the moving average value of the duty ratio in the immediately preceding predetermined moving averaging time is calculated, the limit value is set so as to decrease as the moving average value increases, and the duty ratio is less than the calculated limit value. Limited. Therefore, failure due to burning of the drive motor can be prevented without providing an additional sensor for abnormality determination. For example, when the valve opening command value of the exhaust gas recirculation control valve is determined according to the intake air flow rate of the internal combustion engine detected by the intake air flow rate sensor, water droplets adhere to the intake air flow rate sensor so that it does not operate normally. Otherwise, the valve opening command value becomes an abnormal value, and an excessive current may be supplied to the drive motor of the exhaust gas recirculation control valve. According to the present invention, in such a case, it is determined that there is an abnormality in the motor drive control, and the duty ratio of the drive control signal is limited, so that it is possible to prevent an excessive current from being supplied to the drive motor. it can.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an internal combustion engine and a control device thereof according to an embodiment of the present invention. An internal combustion engine (hereinafter referred to as “engine”) 1 is a diesel engine that directly injects fuel into a cylinder, and a fuel injection valve 6 is provided in each cylinder. The fuel injection valve 6 is electrically connected to an electronic control unit (hereinafter referred to as “ECU”) 5, and the valve opening timing and valve opening time of the fuel injection valve 6 are controlled by the ECU 5.

  The engine 1 includes an intake pipe 7, an exhaust pipe 8, and a turbocharger 9. The turbocharger 9 includes a turbine that is rotationally driven by the kinetic energy of the exhaust, and a compressor that is connected to the turbine via a shaft. The turbocharger 9 pressurizes (compresses) air sucked into the engine 1.

  An intercooler 11 is provided on the compressor downstream side of the intake pipe 7, and an intake shutter valve (hereinafter referred to as “ISV”) 22 is provided on the downstream side of the intercooler 11. The ISV 22 is configured to be opened and closed by an ISV actuator 23, and the ISV actuator 23 is connected to the ECU 5.

  The intake pipe 7 branches to intake pipes 7A and 7B on the downstream side of the ISV 22, and further branches corresponding to each cylinder. FIG. 1 shows only the configuration corresponding to one cylinder. Each cylinder of the engine 1 is provided with two intake valves (not shown) and two exhaust valves (not shown). Intake ports (not shown) that are opened and closed by two intake valves are connected to intake pipes 7A and 7B, respectively.

  In addition, a swirl control valve (hereinafter referred to as “SCV”) 19 that generates a swirl in the combustion chamber of the engine 1 by limiting the amount of air sucked through the intake pipe 7B is provided in the intake pipe 7B. Yes. The SCV 19 is configured to be opened and closed by an SCV actuator 20, and the SCV actuator 20 is connected to the ECU 5.

  The SCV actuator 20 includes a motor that can rotate forward and backward, and drives the SCV 19 in the valve opening direction by rotating the motor forward, while driving the SCV 19 in the valve closing direction by rotating the motor in the reverse direction.

  Between the exhaust pipe 8 and the intake pipe 7A, an exhaust gas recirculation passage 25 that recirculates exhaust gas to the intake pipe 7A is provided. The exhaust gas recirculation passage 25 is provided with an exhaust gas recirculation control valve (hereinafter referred to as “EGR valve”) 26 for controlling the exhaust gas recirculation amount. The EGR valve 26 is configured to be opened and closed by an EGR actuator 27, and the EGR actuator 27 is connected to the ECU 5. The EGR actuator 27 includes a motor that can rotate forward and backward, and drives the EGR valve 26 in the valve opening direction by rotating the motor in the forward direction, while driving it in the valve closing direction by rotating the motor in the reverse direction.

  The ECU 5 supplies a drive control signal with a variable duty ratio to the EGR actuator 27 and the SCV actuator 20 to control the opening degree of the EGR valve 26 and the SCV 19.

  The intake pipe 7 is provided with an intake air flow rate sensor 31 for detecting the intake air flow rate GA and a supercharging pressure sensor 32 for detecting the supercharging pressure PB. The ISV opening sensor 34 detects the opening IS of the ISV 22, the SCV opening sensor 35 detects the opening SC of the SCV 19, and the EGR valve opening sensor 36 detects the opening (lift amount) LACT of the EGR valve 26. The detection signals of these sensors 31 to 36 are supplied to the ECU 5.

  The ECU 5 includes an accelerator sensor 37 that detects an accelerator pedal operation amount (hereinafter referred to as “accelerator pedal operation amount”) AP of the vehicle driven by the engine 1, an engine speed sensor 38 that detects an engine speed NE, and engine cooling. A cooling water temperature sensor 39 for detecting the water temperature TW and an outside air temperature sensor 40 for detecting the outside air temperature TA are connected, and detection signals from these sensors are supplied to the ECU 5.

  The ECU 5 shapes input signal waveforms from various sensors, corrects the voltage level to a predetermined level, converts an analog signal value into a digital signal value, etc., and a central processing unit (hereinafter referred to as “CPU”). A storage circuit for storing various calculation programs executed by the CPU and calculation results, and an output circuit for supplying drive signals to various actuators.

  FIGS. 2A and 2B are block diagrams showing the configuration of modules for calculating the duty ratio of drive control signals supplied to the EGR actuator 27 and the SCV actuator 20, respectively. The function of the module shown in FIG. 2 is realized by processing executed by the CPU of the ECU 5.

  The module shown in FIG. 2A is a module that calculates a drive duty ratio DTED that is a duty ratio of a drive control signal (referred to as an “EGR valve drive control signal”) supplied to the EGR actuator 27, and calculates a target fresh air flow rate. A unit 41, a target EGR valve opening calculation unit 42, a basic duty ratio calculation unit 43, and a drive duty ratio calculation unit 44.

  The target fresh air flow rate calculation unit 41 calculates the target fresh air flow rate GACMD according to the accelerator pedal operation amount AP, the engine speed NE, and the coolant temperature TW. The target EGR valve opening degree calculation unit 42 calculates the target EGR valve opening degree LCMD by feedback control (for example, PID control) so that the detected intake air flow rate GA matches the target fresh air flow rate GACMD.

  The basic duty ratio calculation unit 43 calculates the basic duty ratio DTEB of the EGR valve drive control signal by feedback control (for example, PID control) so that the detected EGR valve opening degree LACT coincides with the target EGR valve opening degree LCMD. . The basic duty ratio DTEB is calculated as a duty ratio having a positive value when the motor is rotated forward, and is calculated as a duty ratio having a negative value when the motor is rotated reversely.

  The drive duty ratio calculation unit 44 executes the processing shown in FIGS. 3 and 5 and calculates the drive duty ratio DTED.

  The module shown in FIG. 2B is a module that calculates a drive duty ratio DTSD that is a duty ratio of a drive control signal (referred to as “SCV drive control signal”) supplied to the SCV actuator 20, and a target SCV opening calculation unit. 51, a basic duty ratio calculation unit 52, and a drive duty ratio calculation unit 53.

The target SCV opening calculation unit 51 calculates the target SCV opening SCCMD according to the accelerator pedal operation amount AP, the engine speed NE, and the cooling water temperature TW.
The basic duty ratio calculation unit 52 calculates the basic duty ratio DTSB of the SCV drive control signal by feedback control (for example, PID control) so that the detected SCV opening SC matches the target SCV opening SCCMD. The basic duty ratio DTSB is calculated as a duty ratio having a positive value when the motor is rotated forward, and is calculated as a duty ratio having a negative value when the motor is rotated reversely.

  The drive duty ratio calculation unit 53 executes a process similar to the process shown in FIGS. 3 and 5 and calculates the drive duty ratio DTSD.

  FIG. 3 is a flowchart of processing in the drive duty ratio calculation unit 44 shown in FIG. This process is executed every first predetermined time (for example, 10 milliseconds).

In step S11, a change amount DDUT of the basic duty ratio DTEB is calculated by the following equation (1). “K” in the equation (1) is a discretization time discretized in the execution cycle of this processing, and indicates that (k) is the current value. Further, dt is a first predetermined time that is an execution cycle of this process.
DDUT = | DTEB (k) −DTEB (k−1) | / dt (1)

  In step S12, it is determined whether or not the change amount DDUT is larger than a predetermined threshold value DDTH (for example, 300% / second). When this answer is negative (NO), the upper limit value DTLMH and the lower limit value DTLML are respectively set to the normal upper limit value DTLMN (for example, 100%) and the normal lower limit value -DTLMN (step S13), and the process proceeds to step S16.

  If DDUT> DDTH and the change amount DDUT is large in step S12, it is determined that an abnormality has occurred in the drive control of the EGR valve 26, and the upper limit value DTLMH and the lower limit value DTLML are set by the following steps S14 and S15. I do.

  That is, in step S14, the DTLMA table shown in FIG. 4 is searched according to the average drive duty ratio DTDAV calculated in the process of FIG. 5, and the abnormal limit value DTLMA (> 0) is calculated. The DTLMA table indicates that the abnormal limit value DTLMA increases as the average drive duty ratio DTDAV increases when the average drive duty ratio DTDAV is in the range of the first predetermined value DT1 (for example, 20%) to the second predetermined value DT2 (for example, 43%). It is set to decrease.

  In step S15, the upper limit value DTLMH and the lower limit value DUTMLML are set to values obtained by adding a negative sign to the abnormal limit value DTLMA and the abnormal limit value DTLMA, respectively, and the process proceeds to step S16.

  In step S16, it is determined whether or not the basic duty ratio DTEB (k) is larger than the upper limit value DTLMH. If the answer is affirmative (YES), the drive duty ratio DTED (k) is set to the upper limit value DTLMH. (Step S17).

  If DTEB (k) ≦ DTLMH in step S16, it is determined whether or not the basic duty ratio DTEB (k) is smaller than the lower limit value DTLML (step S18). If the answer is affirmative (YES), the drive duty ratio DTED (k) is set to the lower limit value DTLML (step S19).

  If DTEB (k) ≧ DTMLML in step S18, the drive duty ratio DTED (k) is set to the basic duty ratio DTEB (k) (step S20).

FIG. 5 is a flowchart of a process for calculating the average drive duty ratio DTDAV. This process is executed every second predetermined time (for example, 100 milliseconds).
In step S31, the integrated value SUMDTED (j) in the latest predetermined averaging time TAV (for example, 1 second) of the absolute value of the drive duty ratio DTED is calculated by the following equation (2). Here, “j” is the discretization time discretized in the execution cycle of the process of FIG. 5, and (j) indicates that this is the current value. NS is the number of data to be averaged, and the data number NS is set to 10, for example.

  In step S32, the average drive duty ratio DTDAV is calculated by dividing the integrated value SUMDTED (j) by the number of data NS.

  Note that the drive duty ratio DTSD of the SCV drive control signal is also calculated by a process similar to the process of FIGS. 3 and 5 described above.

  FIG. 6 is a time chart for explaining the processing of FIGS. 3 and 5. A thin solid line L1 and a thick solid line L2 in FIG. 6A indicate transitions of the basic duty ratio DTEB and the drive duty ratio DTED, respectively. Dashed lines L3 and L4 indicate the transition of the upper limit value DTLMH and the lower limit value DTLML, respectively, and the alternate long and short dash line L5 indicates the transition of the average drive duty ratio DTDAV. FIG. 6B shows the transition of the change amount DDUT.

  When the change amount DDUT of the basic duty ratio DTEB increases and exceeds the predetermined threshold value DDTH, the upper limit value DTLMH and the lower limit value DTLML are applied with the abnormal limit value DTLMA and the corresponding negative value -DTLMA, and the abnormal limit value DTLMA is The average drive duty ratio DTDAV is set so as to decrease as it increases. As a result, the absolute value of the peak value of the drive duty ratio DTED decreases, and the average drive duty ratio DTDAV is limited to a level at which the motor of the EGR actuator 27 does not burn out.

  As described above, in the present embodiment, the drive control abnormality of the actuator 27 (the drive motor included in the actuator 27) is determined based on the change amount DDUT of the basic duty ratio DTEB of the drive control signal supplied to the EGR actuator 27, and the motor drive When it is determined that there is an abnormality in the control, the upper limit value DTLMH and the lower limit value DTLML applied to the calculation of the drive duty ratio DTED are corrected so as to decrease. The basic duty ratio DTSB of the drive control signal supplied to the SCV actuator 20 is also subjected to limit processing similar to that shown in FIGS. 3 and 5 to calculate the drive duty ratio DTSD. Therefore, failure due to burning of the drive motor can be prevented without providing an additional sensor for abnormality determination.

  For example, when water droplets adhere to the intake air flow rate sensor 31 and the normal operation does not occur, the target EGR valve opening degree LCMD is set to an abnormal value, and an excessive current may be supplied to the drive motor of the EGR valve 26. However, according to the processing of FIGS. 3 and 5, in such a case, it is determined that the drive control is abnormal and the drive duty ratio DTED is limited, so that an excessive current is prevented from being supplied to the drive motor. can do.

  Further, when the SCV opening sensor 35 fails, the basic duty ratio DTSB of the SCV drive control signal is set to an abnormal value, and an excessive current may be supplied to the drive motor of the SCV 19. Such problems can also be prevented.

  In the present embodiment, the EGR actuator 27 and the SCV actuator 20 correspond to drive means, and the ECU 5 constitutes abnormality determination means and restriction means. Specifically, steps S11 and S12 in FIG. 3 correspond to abnormality determination means, and steps S14 to S20 and the processing in FIG. 5 correspond to restriction means.

  The present invention is not limited to the embodiment described above, and various modifications can be made. For example, in an engine equipped with either the EGR valve 26 or the SCV 19, the above-described determination of drive control abnormality and drive duty ratio limit processing are performed.

  Further, the present invention can be applied to control of a valve device for an internal combustion engine that is driven by a method similar to that of the above-described embodiment. Furthermore, the present invention can also be applied to a valve device applied to a marine vessel propulsion engine such as an outboard motor having a crankshaft as a vertical direction.

It is a figure which shows the structure of the internal combustion engine and its control apparatus concerning one Embodiment of this invention. It is a block diagram which shows the structure of the module which calculates the duty ratio of the drive control signal of an exhaust gas recirculation | reflux control valve and a swirl control valve. It is a flowchart of the process in the drive duty ratio calculation part shown in FIG. It is a figure which shows the table referred by the process of FIG. It is a flowchart of the process which calculates the average drive duty ratio (DTDAV) referred by the process of FIG. 6 is a time chart for explaining the processing of FIGS. 3 and 5.

Explanation of symbols

1 Internal combustion engine 5 Electronic control unit (abnormality determination means, restriction means)
7, 7A, 7B Intake pipe 8 Exhaust pipe 19 Swirl control valve (valve device)
20 SCV actuator (drive means)
26 Exhaust gas recirculation control valve (valve device)
27 EGR actuator (drive means)

Claims (1)

In a motor control device that controls a drive motor that drives a valve device applied to an internal combustion engine,
A drive means for receiving a drive control signal having a variable duty ratio and supplying a drive current to the drive motor;
An abnormality determining means for determining a drive control abnormality of the drive motor based on a change amount of the duty ratio;
Limiting means for limiting the duty ratio when it is determined by the abnormality determining means that there is an abnormality in the drive control of the motor,
The limiting means is
A moving average value calculating means for calculating a moving average value of the duty ratio in the immediately preceding predetermined moving averaging time;
Limit setting means for setting a limit value so as to decrease as the moving average value increases, and
Limit the duty ratio to be equal to or less than the limit value,
The valve device includes at least one of an exhaust gas recirculation control valve that controls an exhaust amount that recirculates from an exhaust system of the engine to an intake system, and a swirl control valve that controls a swirl in a combustion chamber of the engine. Control device.

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