JP5950868B2 - Control device for motor for fuel pump - Google Patents

Description

  The present invention relates to a control device for controlling a fuel pump motor of an automobile fuel supply device.

  The fuel pump motor of the fuel supply system for automobiles is a motor for driving a fuel pump that pumps the fuel in the fuel tank to the fuel injection valve of the engine. The fuel pressure supplied to the fuel injection valve is the target fuel pressure. Feedback control is performed based on the deviation between the target fuel pressure and the actual fuel pressure detected by the pressure sensor (see, for example, Patent Document 1).

JP 2012-67606 A

  When the fuel pump motor is controlled by pressure, a mechanism for reading the pressure is required, which increases the manufacturing cost.

  Conventionally, PID (proportional / integral / derivative) control is often performed as feedback control, but the manipulated variables of P control and D control are the deviation (target fuel pressure−actual fuel pressure) and the current and previous control values, respectively. Therefore, when the target fuel pressure changes greatly, the manipulated variable reacts quickly and is easy to cause overshoot. For this reason, there is a problem that it is difficult to perform control with high responsiveness to the target fuel pressure. In addition, there is a problem in that there are many control terms and the amount of calculation increases.

  On the other hand, when feedback control is not performed, it is necessary to offset the supply amount to the increase side so that the fuel supply amount does not fall below the target amount. However, an excessive offset leads to wasteful power consumption and affects fuel consumption. There was a problem to do.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel pump motor control device that can perform highly responsive control with a simple configuration.

The fuel pump motor control apparatus according to the present invention converts a command duty signal for driving the fuel pump motor to supply a target amount of fuel from the fuel pump into a target voltage to be applied to the fuel pump motor. Target voltage calculation unit, feed forward control unit that calculates a feed forward voltage based on the amount of change in the target voltage, and integration control that calculates an integral voltage based on the deviation between the voltage applied to the fuel pump motor and the target voltage parts and, summing the feedforward voltage and integrated voltage seeking the applied voltage, the fuel pump motor and an operation Duty generator for generating an operation Duty signals for driving in the applied voltage, feedforward control unit The gain by which the change amount of the target voltage is multiplied is changed according to the sign of the change amount of the target voltage .

According to the present invention, the fuel pump motor is driven using the feedforward voltage calculated based on the amount of change in the target voltage and the integrated voltage calculated based on the deviation between the applied voltage and the target voltage. Since the operation duty signal is generated, the mechanism for reading the pressure, which has been conventionally required, can be eliminated by accurately controlling the voltage applied to the fuel pump motor. Further, since the control object does not have inertia, quick response is expected, and therefore, only integral control that can eliminate the steady-state deviation is performed as feedback control. Accordingly, it is possible to provide a fuel pump motor control device capable of performing highly responsive control with a simple configuration. In addition, since the feedforward control unit changes the gain by which the target voltage change amount is multiplied according to whether the target voltage change amount is positive or negative, the output voltage can be controlled not to fall below the target voltage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an overall configuration of an automobile fuel supply apparatus to which a fuel pump motor control apparatus according to Embodiment 1 of the present invention is applied. FIG. 2 is a block diagram illustrating a configuration of a fuel pump motor control device according to the first embodiment. 6 is a graph showing a simulation result at the time of rising of the output voltage in the first embodiment. FIG. 3 is a block diagram illustrating a configuration of an FF control unit in the fuel pump motor control apparatus according to the first embodiment. In the first embodiment, a graph (a) showing the ideal waveform of the output voltage when the gain of the FF control is switched at the time of rising and falling of the target voltage, and a graph showing the output voltage waveform when the gain is not switched ( b).

Embodiment 1 FIG.
In the automobile fuel supply apparatus shown in FIG. 1, the fuel pump 1 includes a pump main body 1 a and a fuel pump motor 1 b that drives the pump main body 1 a, and is disposed in the fuel tank 2. . The fuel pump 1 is connected to a fuel pressure regulator 7 that controls the fuel pressure in the fuel pipe 3 to a predetermined control pressure, and the fuel injection valve 4. The fuel injection valve 4 is connected to the intake pipe 6 of the engine 5 and is driven and controlled by the engine control device 13 to supply fuel to the engine 5.

  The fuel pressure regulator 7 is connected to the fuel pipe 3 by a branch pipe 11, and includes a spring chamber 8 and a pressure regulating chamber 9 into which fuel in the fuel pipe 3 is introduced via the branch pipe 11. When the predetermined control pressure by the set spring force of the spring 8a becomes larger than the pressure in the pressure regulating chamber 9, the diaphragm 10 is pressed toward the pressure regulating chamber 9, and the valve body 9b attached to the diaphragm 10 is discharged to the discharge port 9a. The mouth is closed. When the set spring force of the spring 8a becomes smaller than the pressure in the pressure adjusting chamber 9, the diaphragm 10 is pressed toward the spring chamber 8, the valve body 9b is separated from the discharge port 9a, and the fuel from the fuel pipe 3 is discharged. The fuel is returned to the fuel tank 2 through the discharge port 9a and the return pipe 12.

  The air flow sensor 14 is disposed in the intake pipe 6 and detects the amount of air taken in from the intake pipe 6 by the engine 5. The engine control device 13 calculates a necessary fuel supply amount based on the air amount detected by the air flow sensor 14 and drives the fuel pump motor 1 b so that the calculated fuel supply amount is pumped from the fuel pump 1. A voltage command value (command duty signal) is output to the fuel pump motor control device 100 and the valve opening time of the fuel injection valve 4 is controlled so that the calculated fuel supply amount is obtained. In addition, the engine control device 13 acquires an operation duty signal that the fuel pump motor control device 100 actually controls the fuel pump 1 for abnormality diagnosis.

  The engine control device 13 issues an ON / OFF command according to the operating state of the engine 5 and switches the power relay 15. When the power supply relay 15 is turned on, power supply from the in-vehicle power supply E to the fuel pump motor control device 100 is started via the ignition switch 16, and the fuel pump motor control device 100 starts the fuel pump motor 1b.

Next, a method for controlling the fuel pump motor 1b by the fuel pump motor control apparatus 100 will be described.
FIG. 2 is a block diagram showing the configuration of the fuel pump motor control apparatus 100. The fuel pump motor control apparatus 100 includes a target voltage calculation unit 101, delay units 102 and 110, subtraction units 103 and 105, a feedforward (FF) control unit 104, an integration (I) control unit 106, and addition units 107 and 109. , A target duty calculation unit 108, and an operation duty generation unit 111. The fuel pump motor control device 100 includes a microcomputer that executes a program describing each process of the fuel pump motor control device 100.

  The fuel pump motor control device 100 receives a command duty signal for driving the fuel pump motor 1b to supply the fuel supply amount from the fuel pump 1 from the engine control device 13, and drives the fuel pump motor 1b. . The fuel pump motor control device 100 uses the result obtained by feeding back the output voltage applied to the fuel pump motor 1b, calculates an operation duty signal by speed type I + FF control, and controls the fuel pump motor 1b according to the operation duty signal. PWM (Pulse Width Modulation) drive is performed to control the discharge amount of the pump body 1a. As for the command to the target voltage calculation unit 101, means such as digital communication may be used instead of the duty signal.

  Specifically, the target voltage calculation unit 101 obtains a target voltage by converting a command duty signal output from the engine control device 13 into a voltage value. The subtraction unit 103 subtracts the previous target voltage delayed by the delay unit 102 from the current target voltage to obtain the amount of change in the target voltage. The FF control unit 104 multiplies the amount of change in the target voltage by a predetermined feedforward gain to determine a feedforward voltage that allows for the change in the target fuel supply amount.

  On the other hand, the output voltage applied to the fuel pump motor 1b is fed back to the subtraction unit 105, and the output voltage is subtracted from the target voltage of the target voltage calculation unit 101, and the deviation between the target voltage and the output voltage is transferred to the I control unit 106. input. The I control unit 106 multiplies the deviation between the target voltage and the output voltage by a predetermined integral gain to determine the integral voltage for canceling the steady deviation and bringing the actual fuel supply amount closer to the target.

  Adder 107 adds the feedforward voltage of FF controller 104 and the integrated voltage of I controller 106 to calculate the total voltage, and target duty calculator 108 converts the total voltage to Duty to obtain the target Duty. . The addition unit 109 adds the current target duty to the previous operation duty delayed by the delay unit 110, calculates an operation duty signal corresponding to the voltage to be applied to the fuel pump motor 1b, and an operation duty generation unit. 111 performs PWM driving of the fuel pump motor 1b in accordance with the operation duty signal.

  Conventionally, PID control or the like is often employed for feedback control of the fuel pump motor 1b, but in the present invention, integral (I) control is employed. The current control target is a voltage, and the influence on the output voltage by the fuel pump motor 1b can be considered. However, since the control target does not have inertia, quick response is expected. In addition, the integral control has an advantage that a steady deviation can be eliminated and a steep change does not occur.

  On the other hand, when proportional (P) control and differential (D) control are employed, the operation amount of proportional control is proportional to the deviation between the target voltage and the output voltage, and the operation amount of differential control is proportional to the variation amount of the deviation. Therefore, when the target voltage changes greatly, the operation amount is large and reacts quickly. Therefore, it causes overshoot and is not suitable for feedback control using voltage as a control target. In addition, the feedback control to which the proportional term and the differential term are added has an adverse effect that the control term increases in addition to an increase in overshoot.

  FIG. 3 is a graph showing a simulation result when the output voltage to the fuel pump motor 1b rises. The solid line indicates the output voltage of the integral control, the alternate long and short dash line indicates the output voltage of the proportional integration control, and the dotted line indicates the target voltage. The integral gain is the same between integral control and proportional integral control. From the graph, it can be seen that in the proportional integral control, at the time of start-up, the target voltage is exceeded by several V and then converges, and the overshoot is larger than that of the integral control alone.

  In feedback control using a constant gain, the output voltage may fall below the target voltage when the target voltage changes greatly. However, due to the characteristics of the fuel pump 1, since the fact that the output voltage falls below the target voltage affects the fuel supply to the engine 5, it is a major premise to control so that it does not fall below the target voltage. Therefore, in the fuel pump motor control apparatus 100, the feedforward gain of the FF control unit 104 is switched between the rising and falling of the target voltage, thereby performing control suitable for each of the rising and falling.

Specifically, as shown in FIG. 4, a rising-side feedforward gain (FF_Gain_UP) 104 a and a falling-side feedforward gain (FF_Gain_DN) 104 b are set in the FF control unit 104, and the target calculated by the subtracting unit 103 is set. The feedforward gains 104a and 104b are switched in accordance with the sign of the amount of voltage change.
The rising-side feedforward gain 104a is set larger than the falling-side feedforward gain 104b, and when the target voltage rises, the output voltage does not fall below the target voltage even if there is some overshoot. Is preferred. Further, the feed-forward gain 104b on the falling side is preferably set to a value where the output voltage gradually decreases and does not fall below the target voltage when the target voltage decreases.

  Further, when the gain of feedforward control is switched between rising and falling, it is necessary to perform control (speed type control) on the amount of change, not control on deviation (position type control). This is because the position type causes an offset when the feedforward gain is switched. Therefore, the fuel pump motor control device 100 calculates the operation duty signal corresponding to the voltage to be applied to the fuel pump motor 1b by adding the current target duty to the previous operation duty delayed by the delay unit 110. Speed type control is implemented.

  FIG. 5A is a graph showing an ideal waveform of the output voltage at the rise and fall of the target voltage. The solid line indicates the output voltage when the feedforward gain is switched between the rising side and the falling side, and the dotted line indicates the target. Voltage. From the graph, the output voltage falls below the target voltage by increasing the feedforward gain at the rise of the target voltage (feedforward gain 104a) and decreasing the feedforward gain at the fall of the target voltage (feedforward gain 104b). There is no. On the other hand, FIG. 5B is a graph when the feedforward gain is not switched. The case where the gain is large is indicated by a solid line, the case where the gain is low is indicated by a one-dot chain line, and the target voltage is indicated by a dotted line. When the gain is large, the output voltage falls below the target voltage when the target voltage falls, and when the gain is small, the output voltage falls below the target voltage when the target voltage rises. Therefore, it is necessary to switch the gain.

Even when the speed type I + FF control as described above is performed, the output voltage drops below the target voltage due to errors caused by tolerances of circuit parts of the fuel pump motor control device 100 such as an output voltage reading error. In some cases, the voltage drop may be corrected by adding an offset.
The offset amount is determined by calculating the tolerance of the output voltage, and when the target voltage calculation unit 101 converts the command duty signal into the target voltage, the voltage (offset) of the tolerance is added to the target voltage. As a result, as shown in FIG. 5, the output voltage becomes higher than the target voltage by the offset amount.

  As described above, according to the first embodiment, the fuel pump motor control device 100 outputs the command duty signal for driving the fuel pump motor 1b to supply the target amount of fuel from the fuel pump 1 to the fuel pump. A target voltage calculation unit 101 that converts the target voltage to be applied to the motor 1b, an FF control unit 104 that calculates a feedforward voltage based on the amount of change in the target voltage, and an output voltage and a target voltage that are applied to the fuel pump motor 1b. The I control unit 106 that calculates the integrated voltage based on the deviation from the above, the feed forward voltage and the integrated voltage are added together to obtain the applied voltage, and an operation duty signal for driving the fuel pump motor 1b with the applied voltage is obtained. An operation duty generation unit 111 for generation is provided. For this reason, the mechanism etc. which read the pressure conventionally required can be made unnecessary by controlling the applied voltage to the fuel pump motor 1b with high accuracy. Further, since the control object does not have inertia, quick response is expected, and therefore, only integral control that can eliminate the steady-state deviation is performed as feedback control. Therefore, the fuel pump motor control device 100 can perform highly responsive control with a simple configuration.

  Further, according to the first embodiment, the FF control unit 104 switches the feedforward gains 104a and 104b according to the sign of the change amount of the target voltage, so that it is suitable for the rising and falling of the target voltage. Can be controlled. Therefore, control can be performed so that the output voltage does not fall below the target voltage.

  Further, according to the first embodiment, the target voltage calculation unit 101 adds the offset for correcting the voltage drop due to the tolerance of the fuel pump motor control apparatus 100 to the target voltage, so that the output voltage is Control that does not fall below the target voltage is possible.

Further, in the control without the conventional feedback function, it is necessary to output the output voltage higher than the target voltage in consideration of a decrease in the output voltage due to an error caused by the circuit parts of the fuel pump motor control device 100. . For this reason, the output voltage becomes higher by about 0.3 to 0.6 V than the output voltage of the present invention, and accordingly, wasteful power consumption and a burden on the fuel pump motor 1b are increased.
In contrast, the speed type I + FF control of the present invention can reduce unnecessary power consumption and the burden on the fuel pump motor 1b. In addition, by performing voltage feedback control, the basic logic can be followed even when the load of the fuel pump motor 1b is different, so that versatility is high.

  In addition to the above, within the scope of the invention, the invention of the present application can be modified with any component of the embodiment or omitted with any component of the embodiment.

  DESCRIPTION OF SYMBOLS 1 Fuel pump, 1a Pump main-body part, 1b Fuel pump motor, 2 Fuel tank, 3 Fuel piping, 4 Fuel injection valve, 5 Engine, 6 Intake pipe, 7 Fuel pressure regulator, 8 Spring chamber, 8a Spring, 9 Pressure regulation chamber , 9a Discharge port, 9b Valve body, 10 Diaphragm, 11 Branch piping, 12 Return piping, 13 Engine control device, 14 Air flow sensor, 15 Power relay, 16 Ignition switch, 100 Fuel pump motor control device, 101 Target voltage calculation unit , 102, 110 delay unit, 103, 105 subtraction unit, 107, 109 addition unit, 104 FF control unit, 104a, 104b feed forward gain, 106 I control unit, 108 target duty calculation unit, 111 operation duty generation unit, E Power supply.

Claims (2)

A control device for a fuel pump motor that drives a fuel pump that supplies fuel in a fuel tank to a fuel injection valve,
A target voltage calculation unit that converts a command duty signal for driving the fuel pump motor to supply a target amount of fuel from the fuel pump into a target voltage to be applied to the fuel pump motor;
A feedforward controller that calculates a feedforward voltage based on the amount of change in the target voltage;
An integration controller that calculates an integrated voltage based on a deviation between the voltage applied to the fuel pump motor and the target voltage;
An operation duty generator that generates an operation duty signal for driving the fuel pump motor with the applied voltage by obtaining the applied voltage by adding the feedforward voltage and the integrated voltage ;
The control apparatus for a fuel pump motor, wherein the feedforward control unit changes a gain by which the change amount of the target voltage is multiplied according to whether the change amount of the target voltage is positive or negative . 2. The fuel pump motor control device according to claim 1, wherein the target voltage calculation unit adds an offset for correcting a drop in the applied voltage due to a tolerance of the control device to the target voltage. 3.

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