JP2005337093A - Load control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress heat generation of a solenoid valve and a switching element and generation of noise and to accurately accomplish an action period of the solenoid valve. <P>SOLUTION: The solenoid valve 22 for fuel injection of an internal combustion engine is controlled by a duty control switching element 29. A period instruction signal representing the opened action period of the solenoid valve 22 is given from a processing circuit 37 to a driving circuit 39. After the driving circuit 39 gives a first value to the solenoid valve 22, it generates a period control signal having a driving period being quick only by an action starting time until it becomes in the opened state and being quick only by an action completion time until it becomes in the closed state by making a current given to load zero. The driving period is set by dividing it to a period, a retaining period and a period and a load current having a large first value is fed to the period and the period. A current of the second value higher than the minimum limitation value required for retaining the action state is given to the retaining period. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for controlling a load such as a solenoid valve.

  The load control device is necessary for controlling a solenoid valve that injects fuel in a fuel injection device (abbreviated as EFI) that injects fuel into an internal combustion engine mounted on a vehicle, for example.

  A typical prior art is shown in FIG. An overcurrent interrupting device 3 of an electronic control unit (ECU) 8 is connected to a load 1 that is an electromagnetic valve that supplies fuel to an internal combustion engine of the fuel injection device. The excessive current interrupting device 3 detects that an excessive current has flowed through the load 1 and thereby interrupts the current flowing through the load 1. A switching element 4 for duty control and a current detection resistor 5 for detecting a load current are connected in series to the load 1, and a voltage across the current detection resistor 5 is detected by a current detection circuit 6.

  FIG. 15 is a waveform diagram for explaining the operation of the prior art shown in FIG. The instruction signal shown in FIG. 15 (3) is derived from the processing circuit 9 such as the microcomputer shown in FIG. 14 to the drive circuit 7 and is given to the drive circuit 7. This instruction signal indicates that the electromagnetic valve as the load 1 keeps the valve open over the period from time t41 to t42. The drive circuit 7 receives the instruction signals representing the times t41 and t42, generates control signals representing the drive start time t51 and the drive end time t52, and gives a switching signal to the switching element 4 via the line 11. The duty of the switching element 4 is controlled.

  FIG. 15 (2) is a waveform diagram showing the passage of time of the load current supplied to the load 1 via the switching element 4. The switching signal supplied to the switching element 4 has a duty ratio at which the load current becomes a predetermined constant value that is a reference symbol I41 in FIG. This current I41 is, for example, a rated current. At time t51, current supply to the load 1 is started, and after a time ΔW41 until the valve 1 is opened, the electromagnetic valve that is the load 1 is opened at time t41. The load current further increases, and the constant current I41 is supplied as described above. In order to stop the load 1 and close the solenoid valve, the switching element 4 is cut off at time t52. Therefore, after time t52, the load current decreases, and at time t42, the electromagnetic valve that is the load 1 is closed.

  The electromagnetic valve which is the load 1 is opened at time t41 when the load current reaches the current value I42 shown in FIG. 15 (2) after the load current starts to be supplied at time t51 as described above. After time t52 when the supply of current to the solenoid valve is cut off, the current flowing through the solenoid valve is closed at time t42 when the current falls to the current value I43. For example, I42> I43. Such an electromagnetic valve applies a spring force toward the valve seat so that the valve body is closed by a spring and supplies the electromagnetic solenoid with a load current to excite the electromagnetic force. Accordingly, the valve body is separated from the valve seat and opened.

  In the prior art shown in FIGS. 14 and 15, a relatively large load current continues to flow through load 1 from time t51 to t52. Therefore, due to such a relatively large load current flowing through the load 1, there is a problem that the heat generation of the load 1 and the heat generation of the switching element 4 are large. Further, since this relatively large current duty control is performed, there is a problem that noise is generated.

  In order to solve this problem, the present applicant has proposed a technique shown in FIG. In the proposed technique, the drive circuit 7 gives a switching signal to the switching element 4 via the line 11 based on the control signal shown in FIG. 16 (1) similar to the control signal shown in FIG. 15 (1). Then, the load current shown in FIG. 16 (2) is supplied to the load 1, thereby controlling the opening and closing of the solenoid valve as the load 1 as shown in FIG. 16 (3). In particular, in this proposed technique, a large current I41 is supplied by duty control of the switching element 4 in the initial period from time t51 to t61, but the electromagnetic valve that is the load 1 is opened at subsequent times t61 to t52. A small holding current I44 greater than a value necessary for maintaining the state is supplied by duty control. By supplying such a holding current I44, heat generation of the load 1 and the switching element 4 can be suppressed, and noise can be reduced. Other configurations of the proposed technique shown in FIG. 16 are similar to the prior art of FIGS.

  The proposed technique shown in FIG. 16 encounters new problems. In the technique shown in FIG. 16, at the time t52 when the supply of the load current to the load 1 is cut off, the current supplied to the load 1 is the holding current I44 as described above, and the current at time t51 to t61. The current I41 given in the period and the current I41 in the prior art shown in FIG. 15 (2), and as a result, the time from the time t52 to the time t53 when the current supplied to the solenoid valve reaches the closing current I43 ΔW43 is short. At time t52, the time change rate of the load current after the supply of current is cut off is the same value as the time change rate of the load current after time t52 shown in FIG. 15 (2). Therefore, the time ΔW43 between the times t52 and t53, which is shorter by the difference ΔW44 than the time ΔW42 at the time t42 when the solenoid valve is closed from the current cutoff time t52 in FIG. As a result, the solenoid valve is driven to the open state only for the same period by the proposed technique shown in FIG. 16 using the instruction signal for setting the periods t41 to t42 in which the solenoid valve is open as it is. It becomes impossible. As a result, the instruction signal shown in FIG. 15 (3) in the existing processing circuit 9 must be reset for a longer time in the proposed technique shown in FIG. 16, which makes setting changes troublesome.

  Another prior art is JP-A-11-89268. In this prior art, when a driven member called a slider is driven from a motor output shaft via a torsion spring and the motor is energized, if the output shaft locks and stops for a predetermined time ΔT, the current supplied to the motor Is reduced to a low holding current that does not cause reverse rotation due to the torsion spring, thereby preventing the motor from generating heat. This prior art does not disclose any configuration for driving a motor as a load for a predetermined accurate period.

JP 11-89268 A

  The object of the present invention is to suppress the heat generation of a load such as a solenoid valve, to suppress the heat generation of a switching element that supplies power to the load, to suppress the generation of noise, and to accurately determine the period of the operating state of the load. It is to provide a load control device that can be set.

The present invention provides a switching element for load drive control interposed between a power source and a load;
Period control signal generating means for generating a period control signal representing the drive start time t11 and the drive end time t14 of the load;
In response to the output of the period control signal generating means, the driving period W2 from the driving start time t11 to the driving end time t14 of the period control signal ends at the initial period W11 starting from the driving start time t11 and the driving end time t14. Period dividing means for dividing and setting an end correction period W13 to be performed and a holding period W12 between the initial period W11 and the end correction period W13;
In response to the output of the period dividing means, the switching element is controlled to the first values I01 and V01 having a large load current or load voltage in the initial period W11 and the end correction period W13, and in the holding period W12, the first Switching control means for controlling the switching element to be smaller than the values I01 and V01, and to be small second values I02 and V02 that are smaller than the values I04 and V04, which are necessary for maintaining the operation state where the load is driven. Is a load control device characterized by

  According to the present invention, the electric power from the power source is supplied to a load such as an electromagnetic valve via the switching element, and the load driving is controlled. The period control signal represents a drive start time t11 and a drive end time t14, and a load current or a load voltage is applied between the drive start time t11 and the drive end time t14. The period dividing means sets the driving period W2 extending from the driving start time t11 to the driving end time t14 to be divided into three periods, that is, divided into an initial period W11, a holding period W12, and an end correction period W13. And set. In the initial period W11 and the end correction period W13, the driving of the switching element is controlled so that a large load current or load voltage of the first values I01 and V01 is applied to the load. The load drive control is, for example, duty control. Duty control refers to switching in which the switching element repeats conduction / cutoff in a short period of time shorter than these periods W11, W12, and W13 in each of the aforementioned periods W11, W12, and W13 in which a load such as the solenoid valve 22 is to be driven. Say control. Since the load is supplied with a load current or load voltage having a predetermined value which is a large first value I01, V01, the load is given the large load current or load voltage to open or close the solenoid valve. The operation start time ΔW1 and the operation end time ΔW2 to be in a state can be set to values predicted in advance based on the characteristics of a load such as a solenoid valve, and the load is set at a high speed, for example, the solenoid valve is opened or closed Can be operated. The first values I01 and V01 may be a rated current or a rated voltage, but may be set to a value of, for example, an inrush current I03 that exceeds those values, further exceeds the inrush current I03, and the load is destroyed. It may be determined in advance to a value less than

  In the holding period W12 after the initial period W11 has passed, predetermined small second values I02 and V02 are given to the load. The second values I02 and V02 are determined to be less than the first values I01 and V01 and to be equal to or higher than the values I04 and V04 necessary for maintaining the operation state where the load is driven. For example, when the load is a solenoid valve, the second values I02 and V02 may be minimum values necessary for maintaining the opened state after the opened state as described above. The initial period W11 described above is, for example, less than 100 msec, and may be, for example, 5 to 20 msec.

  The switching element may be duty-controlled not only in the holding period W12 but also in the initial period W11, and may also be duty-controlled in the subsequent end correction period W13. In the initial period W11 or the end correction period W13, the switching element may be kept conductive without being duty-controlled.

  In the end correction period W13, the switching element is controlled so that a large load current or a large load voltage having the first values I01 and V01 described above is applied to the load. The end correction period W13 may be the same period as the initial period W11, but may be different. In the end correction period W13, the load current or load voltage given to the load is the same value as the large first values I01 and V01 in the initial period W11. Therefore, from the time t14 when the supply of current or voltage to the load is cut off, the operation end time when the load is in a closed state of the electromagnetic valve, for example, can be set to a predetermined accurate prediction time. Therefore, similarly to the prior art described above with reference to FIGS. 14 and 15, the operation state of the load, for example, the period during which the solenoid valve is open can be set accurately.

  According to another concept of the present invention, the load current or the load voltage applied to the load in the end correction period W13 may be a value different from the first values I01 and V01, and the second value I02. , V02, and the operation end time ΔW2 may be a value accurately predicted in advance.

The present invention further includes means for generating a period indicating signal indicating an operation start time t1 and an operation end time t2 at which the load should operate,
The period control signal generating means
In response to the period indication signal,
A drive start time t11 that is earlier than the operation start time t1 is set by the operation start time ΔW1 from when the current or voltage is applied to the load until the operation state is reached,
Driving earlier than the operation end time t2 by the operation end time ΔW2 from when the current or voltage applied to the load is in the operation state until the current or voltage applied to the load begins to become zero until it enters the rest state An end time t14 is set.

  According to the present invention, by supplying a power to the load, generating a period instruction signal for bringing the load into an operating state, for example, an open state by excitation driving of an electromagnetic solenoid of a solenoid valve, and supplying it to the period control signal generating means, A period control signal is obtained by calculation. The drive start time t11 of the period control signal is set earlier by the operation start time ΔW1 than, for example, the operation start time t1 of one of the rising and falling waveforms that is the leading edge of the period instruction signal. The period control signal is also set to the operation end time t14 earlier than the operation end time t2 of the trailing edge which is the other waveform of the rising edge or the falling edge of the period instruction signal. The operation start time ΔW1 is a time required from the time when the current or voltage is applied to the load until the load is changed to a predetermined operation state, for example, from the closed state to the open state of the solenoid valve. The operation end time ΔW2 starts when the current or voltage applied to the load starts to become zero after the current or voltage is applied to the load and the operation state, for example, the solenoid valve is open, and then returns to the rest state, for example, the solenoid valve is closed. It is time until. Thus, for example, a period instruction signal representing a period in which a necessary operation is achieved is generated from a processing circuit such as a computer, whereby a period control signal that is advanced in consideration of the operation start time ΔW1 and the operation end time ΔW2 is calculated. As a result, the load can be accurately set to the operation state from the operation start time t1 to the operation end time t2.

In the present invention, the load is a solenoid valve,
Fuel is supplied to the internal combustion engine via a solenoid valve,
A rotation pulse generating means for generating a rotation pulse for each rotation angle of the output shaft of the internal combustion engine;
The period control signal generating means determines a drive start time t11 and a drive end time t14 of the period control signal in synchronization with the rotation pulse,
Period dividing means
In synchronization with the rotation pulse, the initial period W11, the holding period W12, and the end correction period W13 are divided and set.

In the present invention, the load is a solenoid valve,
The fuel is supplied to the internal combustion engine through an electromagnetic valve.

  According to the invention, the invention can be implemented for a fuel injection device of an internal combustion engine. In an internal combustion engine such as a 2-cycle or 4-cycle gasoline engine, a rotation pulse is generated for each rotation angle of the output shaft corresponding to each stroke, and synchronized with the rotation pulse corresponding to the stroke of the internal combustion engine. The control signal is generated during the period. Therefore, it becomes possible to inject fuel from the electromagnetic valve to the combustion chamber in synchronization with the timing of each stroke of the internal combustion engine.

  The invention can be practiced not only with gasoline engines but also with other types of internal combustion engines.

In the present invention, the period dividing means is:
An auxiliary period signal generating means for generating an auxiliary period signal that lasts only during the period (= W11 + W12) of the initial period W11 and the holding period W12 in the period W2 of the period control signal;
In response to the period control signal, the period W2 of the period control signal is delayed by a delay period DW11 equal to the initial period W11 from the drive start time t11, and the sum of the holding period W12 and the end correction period W13 is And a delay circuit that generates a delay period signal that lasts for a period (= W12 + W13).

  According to the present invention, the auxiliary period signal generating means and the delay circuit are used to divide and set the drive period W2 for driving the load of the period control signal into the initial period W11, the holding period W12, and the end correction period W13. Are provided. Each time t11, t12, t13, t14 can be set based on the auxiliary period signal and the delay period signal of the delay circuit. The auxiliary period signal generating means and the delay circuit can be realized by arithmetic processing such as a microcomputer, but can also be realized by using a logic arithmetic circuit such as a monostable circuit.

In the present invention, the period control signal generating means
When the load driving period W2 is less than the predetermined period W20, the period dividing means is disabled,
Switching control means
The switching element is controlled to the first values I01 and V01 having a large load current or load voltage.

  According to the present invention, when the drive period W2 of the period control signal for setting the drive period W2 for supplying power to the load is less than the predetermined period W20 and is short, the period dividing means is disabled to perform the arithmetic processing operation. Do not do. As a result, heat generation between the load and the switching element is suppressed, wasteful arithmetic processing operation is not performed, operation can be simplified, and arithmetic processing operation is performed at an excessively high speed. There is no need.

  The present invention is implemented not only in connection with a solenoid valve of a fuel injection device that injects fuel during an internal combustion period mounted on an automobile, but also for a wide range of technical fields for controlling the operation of other types of loads. Can be implemented. The load may include an inductance component of a coil such as an electromagnetic solenoid, but may be a resistance and may have other configurations.

  According to the present invention, the load current IL or the load voltage VL is set to the large first values I01 and V01 in the initial period W11 and the end correction period W13 of the drive of the load, whereby the operation start time ΔW1 and the operation The end time ΔW2 is set to a value predicted in advance, whereby an accurate driving period W2 of the load, and thus an accurate operating time W1 can be achieved. In the holding period W12 between the initial period W11 and the end correction period W13, a load current or load voltage having a small second value I02, V02 is applied to the load, thereby suppressing heat generation between the load and the switching element. In addition, generation of noise due to load drive control of the switching element can be suppressed.

  Furthermore, according to the present invention, for example, it can be implemented in relation to a load such as an electromagnetic valve including an electromagnetic solenoid such as an injector for supplying fuel in a fuel injection device of the internal combustion engine, and the operation of the internal combustion engine can be accurately stabilized. Can be realized.

  When the drive period W2 for driving the load or the operation period W1 for operating the load is less than a predetermined value and short, the period dividing means and the like are disabled, and the load and the load are not performed. It is possible to suppress the heat generation of the switching element.

  FIG. 1 is an electric circuit diagram showing the overall configuration of a load control device 21 according to an embodiment of the present invention. FIG. 2 is a waveform diagram for explaining the operation of the load control device 21 shown in FIG. This load control device 21 is connected to an electromagnetic valve 22 having a solenoid coil. In a fuel injection device (abbreviated as EFI) of an internal combustion engine mounted on a vehicle, an electromagnetic valve 22 of an injector is excited and controlled to open and close in order to supply an appropriate amount of fuel. The load control device 21 is electrically connected to an electronic control device (abbreviated as ECU) 48 provided outside the load control device 21. The ECU 48 gives a signal for controlling the electromagnetic valve 22 to the load control device 21 via the line 49.

  Direct current power from a power source 23 such as a battery is supplied from one terminal to an electromagnetic valve 22 connected between both terminals 27 and 28 of the load control device 21 via a line 24 and an overcurrent cutoff circuit 26. Further, the duty control switching element 29 is connected to, for example, another grounded terminal of the power source 23 via the load current detection resistor 32 of the load current detection circuit 31. The load current detection circuit 31 includes the load current detection resistor 32 described above and a buffer 35 to which a voltage corresponding to the load current IL flowing through the load current detection resistor 32 is applied. The output of the buffer 35 is given to the drive circuit 39 and is subjected to negative feedback control with a duty ratio for duty control.

  In the excessive current cutoff circuit 26, an excessive current detection resistor 33 having a low resistance value for detecting an excessive current flowing through the solenoid valve 22 and an excessive current cutoff switching element 25 are interposed in the line 24. Each of the switching elements 25 and 29 is realized by a field effect transistor (abbreviated as FET) having a gate as a control terminal, but may be realized by a switching element such as another transistor.

  In the overcurrent cutoff circuit 26, the control circuit 41 gives an overcurrent cutoff signal to the gate of the switching element 25 via the line 44. The switching element 25 is turned on / off in response to an excessive current cutoff signal via the line 44. The control circuit 41 also has a terminal 45 to which both terminals of the excessive current detection resistor 33 are connected. Therefore, when an excessive current flows through the solenoid valve 22 and the voltage between the pair of terminals 45 becomes a predetermined value or more, the control circuit 41 sends an excessive current cutoff signal from the terminal 43 via the line 44 as described later. Is generated and the switching element 25 is kept shut off to ensure safety.

  The ECU 48 functions as a period instruction signal generating unit, and generates a period instruction signal based on a signal given from the internal combustion engine, for example, a signal indicating a rotation pulse, an air flow rate, and a fuel flow rate output by the internal combustion engine. This period instruction signal is a signal indicating an operation start time t1 and an operation end time t2 of the electromagnetic valve 22, in other words, an operation period W1 in which the electromagnetic valve 22 is open and an operation start time t1.

  Further, the ECU 48 functions as a period control signal generating means, and generates a period control signal shown in FIG. 2 (1) based on the period instruction signal. The ECU 48 gives the generated period control signal via the line 49 to the processing circuit 37 included in the load control device 21. This period control signal has a drive start time t11 that is earlier than the operation start time t1 by the operation start time ΔW1, and has a drive end time t14 that is earlier than the operation end time t2 by the operation end time ΔW2. It has a drive period W2 from a start time t11 to a drive end time t14. The operation start time ΔW1 is the time from the drive start time t11 until the electromagnetic valve 22 is changed from the closed state to the open state. The operation end time ΔW1 is the time from the drive end time t14 until the electromagnetic valve 22 is changed from the open state to the closed state. Such operation start time ΔW1 and operation end time ΔW2 can be accurately predicted and set in advance according to the characteristics of the electromagnetic valve 22. Therefore, when the ECU 48 determines that the solenoid valve 22 should be operated based on the signal given from the internal combustion engine, the ECU 48 generates a period instruction signal, generates a period control signal based on the period instruction signal, and generates the generated period. A control signal is given to the load control device 21, and the ECU 48 controls the operation of the electromagnetic valve 22.

  The processing circuit 37 functions as a period dividing means, and receives a period control signal shown in FIG. The processing circuit 37 is realized by a microcomputer, for example. In response to the period control signal, the processing circuit 37 divides the drive period W2 from time t11 to t14 of the period control signal into three periods, that is, an initial period W11, a holding period W12, and an end correction period W13. And set. The initial period W11 is a period from drive start time t11 to time t12. The holding period W12 is a period from time t12 to time t13. The end correction period W13 is a period from time t13 to drive end time t14. In response to the period control signal, the processing circuit 37 generates a signal indicating the holding period W12, for example, as shown in FIG. The processing circuit 37 gives a control signal indicating each time t11, t12, t13, t14 to the drive circuit 39 based on the signal shown in FIG. 2 (2) and the period control signal.

  The drive circuit 51 functions as a switching control means, and, as shown in FIG. 2 (3), the duty control switching element has values I01, I02, I01 for each of the divided periods W11, W12, W13. 29 is duty controlled. I01> I02, and the second value I02 is set in advance to a small value equal to or larger than the minimum value I04 necessary for maintaining the opened state after the solenoid valve 22 is once opened. . The drive circuit 39 applies a switching signal to the line 40 to control the duty of the duty control switching element 29. Therefore, as shown in FIG. 2 (4), the load current IL supplied to the electromagnetic valve 22 is duty-controlled so as to become the first value I01 in the initial period W11 and the end correction period W13, and in the holding period W12. The duty is controlled so as to be the second value I02.

  Therefore, as shown in FIG. 2 (5), the solenoid valve 22 is supplied with a current at the drive start time t11 and is closed at the operation start time t1 after the operation start time ΔW1 has elapsed from the drive start time t11. Will be open. Further, as shown in FIG. 2 (5), the solenoid valve 22 starts to zero the current applied to the solenoid valve 22 at the drive end time t14, and at the operation end time t2 after the operation end time ΔW2 has elapsed from the drive end time t14. From the open state to the closed state. Therefore, the electromagnetic valve 22 is kept open from the time t1 over the operation period W1.

  FIG. 3 is a flowchart for explaining the operation of the processing circuit 37. The processing circuit 37 repeats the operation shown in FIG. 3 in a short time. Moving from step a1 to step a2, the processing circuit 37 determines whether or not a period control signal via the line 49 has been received from the ECU 48. If received, the processing circuit 37 moves to step a3, and if not received, moves to step a7. . In step a3, the processing circuit 37 calculates a time t12 from the drive start time t11 and the drive period W2 indicated by the period control signal and a predetermined initial period W11, and proceeds to step a4.

  In step a4, the processing circuit 37 calculates a time t13 from the driving end time t14 and the driving period W2 indicated by the period control signal, and a predetermined end correction period W13, and proceeds to step a5. In step a5, the processing circuit 37 calculates the holding period W12 from time t12 and time t13 (W12 = W2− (W11 + W13)), and proceeds to step a6. In step a6, the processing circuit 37 gives a control signal indicating each time t11, t12, t13, t14 to the drive circuit 39, proceeds to step a7, and ends a series of operations.

  FIG. 4 is a flowchart for explaining the operation of the drive circuit 39. The drive circuit 39 repeats the operation shown in FIG. 4 in a short time. Moving from step b1 to step b2, the drive circuit 39 determines whether or not a control signal via the line 38 has been received from the processing circuit 37. If received, the process proceeds to step b3, and if not received, the drive circuit 39 proceeds to step b5. Move. In step b3, the drive circuit 39 generates a switching signal for duty control based on the received control signal, gives it to the gate of the switching element 29 via the line 40, and proceeds to step 4.

  In step b4, the drive circuit 39 receives the load current IL from the load current detection circuit 31, and the detected load current IL is a target value for each period W11, W12, W13 by negative feedback control. The duty ratio is corrected so that the first value I01, the second value I02, and the first value I01 are obtained, the duty control of the duty control switching element 29 is performed, and the process proceeds to step b5 to perform a series of processes. finish. Thus, the control of the load current IL shown in FIG.

  FIG. 5 is a waveform diagram for explaining the duty control operation of the duty control switching element 29. The duty control switching element 29 is turned on only in the first period W21, and is cut off in the next second period W22. At this time, the duty ratio D is the sum of the first and second periods W21, W22 W23 ( = W21 + W22), D = W21 / W23. The period W23 may not be a constant value, but in another embodiment of the present invention, the total time W23 may be a predetermined constant value. The duty ratio D is controlled by the drive circuit 39, and the first and second current values I01 and I02 applied to the electromagnetic valve 22 are changed and set.

  FIG. 6 is a flowchart for explaining the operation of the control circuit 41. The control circuit 41 repeats the operation shown in FIG. 6 in a short time. Moving from step c1 to step c2, the control circuit 41 determines whether the voltage across the terminal 45, that is, the voltage across the excessive current detection resistor 33 is equal to or higher than the high voltage VLL corresponding to the predetermined excessive current ILL. Otherwise, the process proceeds to the next step c3, and the switching element 25 is turned on. The predetermined excessive current ILL is a value that exceeds the first current value I01 described above (I01 ≦ ILL), and the electromagnetic valve 22 may be burned when such excessive current flows through the electromagnetic valve 22. .

  In step c4, the control circuit 41 determines that the load current IL flowing through the solenoid valve 22 is greater than or equal to the first or second value I01, I02 and exceeds the predetermined excessive current value in the excessive current detection resistor 33. When it is determined that a current has flowed, the switching element 25 is then held in a disconnected state to ensure safety. Such an excessive current is caused by a short circuit of the solenoid coil of the solenoid valve 22 or the like.

  Thus, in the present embodiment, in the end correction period W13, the load current IL given to the electromagnetic valve 22 is the same value as the large first value I01 in the initial period W11. Therefore, from time t14 when the supply of current to the solenoid valve 22 is interrupted, the operation end time ΔW2 when the solenoid valve 22 is in the closed state can be set to the predetermined accurate prediction time. Therefore, similarly to the prior art described above with reference to FIGS. 14 and 15, the period during which the electromagnetic valve 22 is in the open state can be set accurately.

  Further, in the present embodiment, in the holding period W12 between the initial period W11 and the end correction period W13, a small load current having a second value I02 is applied to the electromagnetic valve 22, and thereby the electromagnetic valve 22 and the duty control Heat generation with the switching element 29 can be suppressed, and generation of noise due to control of the duty control switching element 29 can be suppressed.

  FIG. 7 is a waveform diagram for explaining the operation of another embodiment of the present invention. This embodiment is similar to the embodiment of FIGS. 1 to 6 described above, and corresponding parts are denoted by the same reference numerals. In the present embodiment, the method for calculating the retention period W12 is different from the above-described embodiment.

  The period control signal generated by the ECU 48 is shown in FIG. 7 (1), and this period control signal is similar to the above-described FIG. 2 (1). The waveform shown in FIG. 7 (2) is a rotation pulse generated by a rotation speed sensor attached to the output shaft of the internal combustion engine. The rotation speed sensor functions as a rotation pulse generating means, generates a rotation pulse at every predetermined angle of the output shaft, and applies the rotation pulse to the processing circuit 37 via the line 49.

  FIG. 8 is a flowchart for explaining the operation of the processing circuit 37 of the present embodiment. The processing circuit 37 repeats the operation shown in FIG. 8 in a short time. Moving from step d1 to step d2, the processing circuit 37 determines whether or not a period control signal is received from the ECU 48 via the line 49. If received, the processing circuit 37 moves to step d3, and if not received, moves to step d8. . In step d3, the processing circuit 37 determines whether or not a rotation pulse via the line 49 has been received from the ECU 48. If it has been received, the processing circuit 37 proceeds to step d4, and if not, proceeds to step d8.

  In step d4, the processing circuit 37 calculates time t12 from the drive start time t11 and the drive period W2 indicated by the period control signal, the rotation pulse, and the initial period W11, and proceeds to step d5. In this embodiment, the drive start time t11 and the drive end time t14 are synchronized with the rotation pulse shown in FIG. 7 (2), that is, either the rising or falling waveform of the rotation pulse (for example, in this embodiment) In the form, it is set in synchronization with the falling waveform). The initial period W11 is set by the count value of the rotation pulse counted by the counter provided in the processing circuit 37.

  In step d5, the processing circuit 37 calculates time t13 from the drive end time t14 and drive period W2 indicated by the period control signal, the rotation pulse, and the final correction period W13, and then proceeds to step d6. The final correction period W13 is set by the count value obtained by counting the rotation pulses by the counter provided in the processing circuit 37.

  In step d6, the processing circuit 37 calculates the holding period W12 from time t12 and time t13 (W12 = W2− (W11 + W13)), and proceeds to step d7. In step d7, the processing circuit 37 gives a control signal indicating each time t11, t12, t13, t14 to the drive circuit 39, proceeds to step d8, and ends a series of operations.

  As described above, the times t12 and t13 for each of the initial period W11, the holding period W12, and the end correction period W13 are set in synchronization with the rotation pulse as shown in FIG. 7 (3). The signal shown is generated. The signal shown in FIG. 7 (3) corresponds to the above-described FIG. 2 (3). As described above, each of the periods W11 and W13 is set by the counter value provided in the processing circuit 37 and counting the rotation pulses. Other configurations and operations are the same as those of the above-described embodiment. As described above, the processing circuit 37 calculates the holding period W12, whereby the same effects as those of the other embodiments described above can be achieved. Further, since the load current IL is controlled using the rotation pulse, it becomes possible to inject fuel from the electromagnetic valve to the combustion chamber in synchronization with the timing of each stroke of the internal combustion engine.

  FIG. 9 is an electric circuit diagram showing an overall configuration of a load control device 21 according to still another embodiment of the present invention. This embodiment is similar to the embodiment of FIGS. 1 to 6 described above, and corresponding parts are denoted by the same reference numerals. FIG. 10 is a waveform diagram for explaining the operation of the load control device 21 shown in FIG. It should be noted that in this embodiment, the processing circuit 37 further functions as an auxiliary period signal generating means, and based on the period control signal shown in FIG. 10 (1), the auxiliary period signal shown in FIG. 10 (2). To line 38. The waveforms in FIGS. 10 (4) to 10 (6) correspond to the waveforms in FIGS. 2 (3) to 2 (5), respectively.

  FIG. 11 is a flowchart for explaining the operation of the processing circuit 37. The processing circuit 37 repeats the operation shown in FIG. 11 in a short time. Moving from step e1 to step e2, the processing circuit 37 determines whether or not a period control signal is received from the ECU 48 via the line 49. If received, the processing circuit 37 moves to step e3, and if not received, moves to step e5. . In step e3, the processing circuit 37 calculates a time t13 from the driving end time t14 and the driving period W2 indicated by the period control signal, and a predetermined end correction period W13, and then proceeds to step e4. In step e4, the processing circuit 37 generates an auxiliary period signal and proceeds to step e5. In step e5, the processing circuit 37 provides the auxiliary period signal to the drive circuit 39 and the delay circuit 71, and proceeds to step e6, where the series of operations is terminated.

  As described above, the processing circuit 37 provides the auxiliary period signal to the drive circuit 39 and also to the delay circuit 71. The auxiliary period signal is shown in FIG. 10 (2) as described above. Of the driving period W2 indicated by the period control signal, the remaining period excluding the end correction period W13 (= W2−W13), in other words, the driving period. Of W2, it persists over time t11 to t13, which is the sum period (= W11 + W12) of the initial period W11 and the holding period W12.

  FIG. 12 is a flowchart for explaining the operation of the delay circuit 71. Delay circuit 71 repeats the operation shown in FIG. 12 in a short time. From step f1 to step f2, the delay circuit 71 determines whether or not an auxiliary period signal has been received from the processing circuit 37. If it has been received, the delay circuit 71 proceeds to step f3, and if not received, proceeds to step f5. In step f3, the delay circuit 71 delays the auxiliary period signal by a predetermined delay period WD11, creates the delay period signal shown in FIG. 10 (3), and proceeds to step f4. Delay period WD11 is set to, for example, a predetermined initial period W11. In step f4, the delay circuit 71 gives a delay period signal to the drive circuit 39 via the line 73, and proceeds to step f5 to end a series of operations.

  Thus, the delay circuit 71 generates a delay period signal. The delay period signal is a remaining period (= W2−W11) excluding the initial period W11 in the driving period W2, in other words, a time t12 which is a sum period (= W12 + W13) of the holding period W12 and the end correction period W13. Persists for ~ t14. Delay circuit 71 is realized, for example, by a logic circuit including a monostable circuit, and has a configuration in which delay time DW11 due to monostable is set equal to initial period W11 and reset at time t14. In the present embodiment and each of the above-described embodiments, W11 = W13 may be used, but the periods W11 and W13 may be different.

  Since the driving circuit 39 is supplied with the auxiliary period signal shown in FIG. 10 (2) and the delay period signal shown in FIG. 10 (3), the time t11 of the auxiliary period signal is set and the time t12 of the delay period signal is set. Is set, and the time t13 of the auxiliary period signal is set to determine the above-described periods W11, W12, and W13. Therefore, the drive circuit 39 is given a signal indicating each time t11, t12, t13, t14. As a result, the duty control switching element 29 is duty controlled and the load current IL is controlled as in the above-described embodiments.

  Thus, in the present embodiment, the auxiliary period signal is used to divide and set the drive period W2 for driving the electromagnetic valve 22 of the period control signal into the initial period W11, the holding period W12, and the end correction period W13. And a delay period signal are used. As a result, signals indicating the times t11, t12, t13, and t14 can be given to the drive circuit 39. The processing circuit 37 and the delay circuit 71 can be realized by arithmetic processing such as a microcomputer, but can also be realized by using a logical arithmetic circuit such as a monostable circuit. Therefore, other effects similar to those of the above-described embodiments can be achieved.

  FIG. 13 is a flowchart for explaining the operation of the processing circuit 37 according to another embodiment of the present invention. The processing circuit 37 repeats the operation shown in FIG. 13 in a short time. The embodiment shown in FIG. 13 is similar to the embodiment described above with reference to FIGS. 1 to 6, and will be described with the same reference numerals. Moving from step g1 to step g2, the processing circuit 37 determines whether the drive period W2 of the period control signal calculated and calculated is equal to or longer than a predetermined relatively short period W20 (W2 ≧ W20). If it is determined that the driving period W2 of the electromagnetic valve 22 as the load is equal to or longer than the predetermined short period W20, in the next step g3, the operations of steps a3 to a7 in FIG. 3 described above are executed.

  If the driving period W2 of the electromagnetic valve 22 is less than the predetermined short period W20 in step g2, the process proceeds from step g2 to step g4, and the processing circuit 37 performs the electromagnetic operation of the electromagnetic valve 22 over the entire period of the short driving period W2. The solenoid is excited so that the large load current IL having the first value I01 flows. Thus, if the drive period W2 is less than the short period W20, the arithmetic processing operation of steps a3 to a7 in FIG. 3 is not performed, thereby eliminating unnecessary arithmetic processing operation and performing high-speed arithmetic processing. Disappears. In such a driving period W2 shorter than the above-described predetermined period W20, heat generation of the current valve 22 and the duty control switching element 29 is suppressed, and the generated noise does not hinder the practical use. .

  In each of the above embodiments, the present invention has been implemented in connection with the control of the load current flowing in the load. However, in still another embodiment of the present invention, the load current IL is changed to a load at both ends of the load. The voltage VL may be implemented in relation to the first and second voltage values V01 and V02 corresponding to the first and second current values I01 and I02 described above. The internal combustion engine may be a type of internal combustion engine such as a 2-cycle or 4-cycle gasoline engine, or may be another internal combustion engine.

It is an electric circuit diagram which shows the whole structure of the load control apparatus 21 of one Embodiment of this invention. It is a wave form diagram for demonstrating operation | movement of the load control apparatus 21 shown by FIG. 4 is a flowchart for explaining the operation of a processing circuit 37. 3 is a flowchart for explaining the operation of a drive circuit 39. 6 is a waveform diagram for explaining a duty control operation of a duty control switching element 29. FIG. 3 is a flowchart for explaining the operation of a control circuit 41. It is a wave form diagram for demonstrating operation | movement of the other embodiment of this invention. 4 is a flowchart for explaining the operation of a processing circuit 37. It is an electric circuit diagram which shows the whole structure of the load control apparatus 21 of the further another form of implementation of this invention. It is a wave form diagram for demonstrating operation | movement of the load control apparatus 21 shown by FIG. 4 is a flowchart for explaining the operation of a processing circuit 37. 3 is a flowchart for explaining the operation of a drive circuit 39. It is a flowchart for demonstrating operation | movement of the processing circuit 37 of other embodiment of this invention. 1 is a diagram showing a typical prior art. FIG. 15 is a waveform diagram for explaining the operation of the prior art shown in FIG. 14. It is a wave form diagram for demonstrating operation | movement of another prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Load control apparatus 22 Solenoid valve 23 DC power supply 26 Overcurrent interruption circuit 29 Duty control switching element 31 Load current detection circuit 37 Processing circuit 39 Drive circuit 48 ECU
71 Delay circuit

Claims (6)

A switching element for load drive control interposed between the power source and the load;
Period control signal generating means for generating a period control signal representing the drive start time t11 and the drive end time t14 of the load;
In response to the output of the period control signal generating means, the driving period W2 from the driving start time t11 to the driving end time t14 of the period control signal ends at the initial period W11 starting from the driving start time t11 and the driving end time t14. Period dividing means for dividing and setting an end correction period W13 to be performed and a holding period W12 between the initial period W11 and the end correction period W13;
In response to the output of the period dividing means, the switching element is controlled to the first values I01 and V01 having a large load current or load voltage in the initial period W11 and the end correction period W13, and in the holding period W12, the first Switching control means for controlling the switching element to be smaller than the values I01 and V01 and to be small second values I02 and V02 that are smaller than the values I04 and V04 necessary for maintaining the operation state where the load is driven. A load control device. Means for generating a period indicating signal indicating an operation start time t1 and an operation end time t2 at which the load should operate;
The period control signal generating means
In response to the period indication signal,
A drive start time t11 that is earlier than the operation start time t1 is set by the operation start time ΔW1 from when the current or voltage is applied to the load until the operation state is reached,
Driving earlier than the operation end time t2 by the operation end time ΔW2 from when the current or voltage applied to the load is in the operation state to when the current or voltage applied to the load starts to zero until the operation is stopped The load control device according to claim 1, wherein an end time t14 is set. The load is a solenoid valve,
Fuel is supplied to the internal combustion engine via a solenoid valve,
A rotation pulse generating means for generating a rotation pulse for each rotation angle of the output shaft of the internal combustion engine;
The period control signal generating means determines a drive start time t11 and a drive end time t14 of the period control signal in synchronization with the rotation pulse,
Period dividing means
2. The load control apparatus according to claim 1, wherein the initial period W11, the holding period W12, and the end correction period W13 are divided and set in synchronization with the rotation pulse. Period dividing means
An auxiliary period signal generating means for generating an auxiliary period signal that lasts only during the period (= W11 + W12) of the initial period W11 and the holding period W12 in the period W2 of the period control signal;
In response to the period control signal, the period W2 of the period control signal is delayed by a delay period DW11 equal to the initial period W11 from the drive start time t11, and the sum of the holding period W12 and the end correction period W13 is The load control device according to claim 1, further comprising a delay circuit that generates a delay period signal that lasts for a period (= W12 + W13). The period control signal generating means
When the load driving period W2 is less than the predetermined period W20, the period dividing means is disabled,
Switching control means
The load control device according to claim 1, wherein the switching element is controlled to a first value I01, V01 having a large load current or load voltage. The load is a solenoid valve,
6. The load control device according to claim 1, wherein fuel is supplied to the internal combustion engine via a solenoid valve.

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