JP6495125B2 - Power supply device for internal combustion engine - Google Patents

Description

  The present invention relates to a power supply apparatus for an internal combustion engine that supplies electric power to various loads including electrical components necessary for operating the internal combustion engine using a magnet generator driven by the internal combustion engine as a power source.

  In an apparatus such as a traveling vehicle equipped with an internal combustion engine, for example, as disclosed in Patent Document 1, an engine is operated from a power supply device that generates a DC voltage using a magnet generator driven by the internal combustion engine as a power source. Electric power is supplied to the electrical equipment load necessary for the operation.

  As shown in FIG. 9, this type of power supply device includes various electrical components necessary for operating the internal combustion engine using the AC voltage output from the magnet generator 1 driven by the internal combustion engine as an input. A regulator 3 that outputs a regulated DC voltage applied to the load 2 and an output capacitor 4 connected between the output terminals of the regulator 3 are provided. The regulator 3 includes thyristors S1 and S2 constituting input terminals a and b to which the output of the generator 1 is input, output terminals c and d to which the load 2 is connected, diodes D1 to D4, and a voltage adjusting switch element. And having the function of converting the AC voltage input from the magnet generator 1 between the input terminals a and b into a DC voltage and providing it between the output terminals c and d, and the output terminal c by turning on and off the thyristors S1 and S2. , D, and a control circuit 3B for controlling the thyristors S1 and S2 so as to keep the DC voltage between the output terminals below the adjustment voltage. ing.

  The regulator 3 shown in FIG. 9 is a so-called short-circuit regulator, and the rectifier elements D1 to D4 constituting the voltage conversion circuit 3A are connected in a full bridge so as to constitute a full-wave rectifier circuit, and the thyristors S1 and S2 are bridged Are connected in antiparallel to both ends of the diodes D3 and D4 constituting the lower side (with the forward direction facing the forward direction and the reverse direction of the diodes D3 and D4).

  The control circuit 3B detects the voltage between the output terminals c and d (hereinafter referred to as the output terminal voltage), and keeps the thyristors S1 and S2 in the off state when the detected voltage is less than the set adjustment voltage. Thus, the output of the rectifier circuit is output from the output terminals c and d, and when the detected voltage is equal to or higher than the adjustment voltage, a trigger signal is given to the thyristors S1 and S2, and the output of the generator 1 is connected to the thyristor S1 and the diode D4. By performing a short circuit through the series circuit or the series circuit of the thyristor S2 and the diode D3, control is performed to stop the output of power from between the output terminals.

JP 2007-192170 A

  A device to which the power supply device shown in FIG. 9 is applied is a so-called battery-less device in which a battery is not mounted. Fuel is supplied to the internal combustion engine in the load 2 of the power supply device shown in FIG. It is essential to drive the engine to operate, such as a fuel pump that supplies fuel to the fuel injection device, an ignition device that ignites the engine, and an ECU (electronic control unit) that configures the means for controlling these with a microprocessor Electrical components (hereinafter referred to as “essential electrical components”).

  If the device driven by the internal combustion engine is not equipped with a battery, the number of revolutions during cranking to start the engine is limited. It is necessary to generate a voltage necessary for driving essential electrical components from when the rotation speed of the crankshaft is as low as possible.

  In addition, when an ECU (Electronic Control Unit or Engine Control Unit) that constitutes various control means by a microprocessor is used to control the internal combustion engine, when the engine is stopped, the microprocessor performs an engine stop process. Therefore, it is necessary to keep supplying the power supply voltage to the microprocessor for a certain time even after the engine is stopped. Therefore, the internal combustion engine power supply apparatus applied to the battery-less equipment as described above requires not only that the output voltage rises as early as possible when the engine is started, but also the generator is stopped when the engine is stopped. Therefore, it is necessary to keep the supply of the voltage to the load for a certain period of time after the output is stopped.

  The output characteristics of the power supply device shown in FIG. 9 greatly depend on the capacitance of the output capacitor 4 connected between the output terminals of the regulator 3. When the capacitance of the capacitor 4 is reduced, as shown in FIG. 10A, after starting the engine at time t1, the voltage between the output terminals of the regulator quickly rises and starts the starting operation. Immediately after time ta, the voltage between the output terminals reaches the voltage Va necessary for driving the electrical component load essential for operating the engine, so that the engine can be easily started.

  On the other hand, when the capacitance of the capacitor 4 is increased, as shown in FIG. 10B, the rise of the voltage between the output terminals after starting the engine starting operation at time t1 is delayed, and the output terminal Since the time ta ′ at which the voltage reaches the voltage Va necessary for driving the electrical component load essential for operating the engine is delayed as compared with the case where the capacitance of the capacitor 4 is reduced, the startability of the engine Becomes worse.

  Further, when the capacitance of the capacitor 4 is reduced, as shown in FIG. 10A, the output terminal voltage falls after the engine is stopped at time t2 to stop the generator output. Therefore, at time tb shortly after time t2 when the engine is stopped, the voltage between the output terminals decreases to the lower limit value (allowable lower limit value) Vb of the voltage range necessary for holding the microprocessor in the operating state. As a result, the microprocessor constituting the ECU cannot complete the engine stop process.

  On the other hand, when the capacitance of the output capacitor 4 is increased, as shown in FIG. 10B, the fall of the voltage between the output terminals after the engine is stopped at time t2 is delayed. The time from the time t2 when the engine is stopped to the time tb ′ when the output voltage drops to the allowable lower limit value Vb is sufficiently long, and during this time, the microprocessor can complete the engine stop process.

  As described above, in the power supply device for an internal combustion engine having the configuration in which the output capacitor 4 is connected between the output terminals of the regulator 3, there is a requirement that the voltage rises quickly at the start of the engine, and even after the engine is stopped. Therefore, it was difficult to satisfy both of these requirements because the requirement to continue outputting the voltage for a long time was in conflict. In particular, immediately after the engine is stopped, various processing such as storing the operation time of the engine up to that point and the stop position of the actuator in a nonvolatile memory such as an EEPROM is performed as an ECU microprocessor as an engine stop process. As a result, the time required for the microprocessor to perform the engine stop process tends to be longer. When a conventional power supply device for an internal combustion engine is used, if the device is designed with priority given to facilitating the start of the engine, there is a possibility that the engine stop process cannot be completed. There was a risk that the data could be destroyed due to an illegal termination of the engine shutdown process. Further, when the power supply device is designed with priority given to causing the microprocessor to complete the engine stop process, the startability of the engine is deteriorated and it is difficult to start the engine manually.

  In the above description, the case where the device driven by the internal combustion engine does not have a battery (battery-less device) is taken as an example. However, even if the device is mounted, the internal combustion engine is not dependent on the battery. The same problem occurs in a device (battery-independent device) in which the power supply device is designed so as to enable operation.

  The object of the present invention is to reliably complete the engine stop process to be performed by the microprocessor of the ECU that controls the internal combustion engine when the internal combustion engine is stopped, without depending on the battery and without sacrificing the startability of the engine. It is an object of the present invention to provide a power supply device for an internal combustion engine that can be made to operate.

The present invention is an electrical terminal that is indispensable to be driven to operate an input terminal to which an output of an alternator driven by an internal combustion engine controlled by an ECU including a microprocessor is input, and the internal combustion engine. Output terminal connected to a load including essential electrical components, and when the voltage between the output terminals is less than the adjustment voltage, DC power is output from the output terminal, and the voltage between the output terminals is equal to or higher than the adjustment voltage. An internal combustion engine power supply device including a regulator that stops the output of the DC power at a certain time and an output capacitor connected between output terminals of the regulator is an object.

  The essential electrical components are, for example, a fuel pump that supplies fuel to a fuel injection device that supplies fuel to the internal combustion engine, an ECU that controls the internal combustion engine, and the like.

In the present invention, an auxiliary capacitor connected between the output terminals of the regulator via a capacitor input switch, and the capacitor input switch is turned on when the voltage between the output terminals of the regulator exceeds a set voltage. In this way, a capacitor input switch control means for controlling the capacitor input switch is provided. The set voltage is set to a voltage that is equal to or higher than the voltage between the output terminals of the regulator when the essential electrical component starts operation and less than the adjustment voltage . Further, the voltage between the output terminals of the regulator is maintained at a level higher than that required for maintaining the microprocessor in an operating state for a time required for the microprocessor to perform the engine stop processing after the internal combustion engine is stopped. Therefore, the sum of the capacitance of the output capacitor and the capacitance of the auxiliary capacitor is set.

  With the above configuration, the auxiliary capacitor is kept disconnected from the output capacitor until the voltage between the output terminals of the regulator reaches the set voltage when the internal combustion engine is started, and the voltage between the output terminals of the regulator becomes the set voltage. After reaching, the auxiliary capacitor is connected in parallel to the output capacitor.

  With this configuration, after the start operation of the engine is started, the voltage between the output terminals of the regulator is at least until the voltage between the output terminals of the regulator reaches a voltage necessary for operating the essential electrical components. Since only the output capacitor can be charged by the voltage, the rise of the voltage between the output terminals of the regulator (the voltage across the output capacitor) can be accelerated to improve the engine startability.

  In addition, after the voltage between the output terminals of the regulator reaches the set voltage, an auxiliary capacitor is connected in parallel to the output capacitor. Therefore, the capacitance of the capacitor charged by the output of the regulator is increased, and the capacitor A sufficiently large amount of energy can be stored. When the engine stops and the generator stops outputting, not only the charge accumulated in the output capacitor but also the charge accumulated in the auxiliary capacitor can be used for driving the load. The time for supplying electric power to the load after stopping can be made sufficiently long, and the microprocessor of the ECU that controls the internal combustion engine can perform the engine stop processing without any trouble.

  According to the present invention, since the microprocessor can secure a sufficiently long time for the engine stop processing when the engine is stopped without impairing the startability of the engine, the control to be performed by the microprocessor can be performed. Even when complicated and it takes a long time to complete the engine stop process, the system driven by the internal combustion engine can be a system whose power source does not depend on the battery.

  After starting the internal combustion engine starting operation with the capacitor input switch turned off, the capacitor capacitance that needs to be charged with the voltage across the output terminals of the regulator increases rapidly when the capacitor input switch is turned on. As a result, a drop occurs in the voltage between the output terminals of the regulator. There is no particular problem if the voltage drop does not cause the voltage across the output terminals of the regulator to be lower than the lower limit (allowable lower limit voltage) of the voltage range necessary to keep the essential electrical components in operation. However, if the voltage between the output terminals of the regulator falls below the allowable lower limit voltage when the auxiliary capacitor is turned on, the operation of essential electrical components will be adversely affected. Even if the voltage between the output terminals of the regulator drops, it is preferable that the voltage does not fall below the lower limit value of the voltage range necessary to keep the essential electrical component in the operating state.

  Therefore, in a preferred aspect of the present invention, when the capacitor input switch control means is in a state where the capacitor input switch is on and the voltage between the output terminals of the regulator becomes lower than the allowable lower limit voltage set lower than the set voltage. Switch-off control that turns off the capacitor input switch, and on-return control that turns on the capacitor input switch when the voltage between the output terminals of the regulator exceeds the set voltage due to the switch-off control being performed. And is further configured to perform.

  If configured as described above, when the auxiliary capacitor is turned on, it is possible to prevent the voltage between the output terminals of the regulator from falling below the allowable lower limit voltage, thus affecting the operation of essential electrical components. Instead, an auxiliary capacitor can be inserted to prepare for the processing when the microprocessor is stopped when the engine is stopped.

  The capacitor input switch control means keeps the capacitor input switch on until the voltage between the output terminals of the regulator once exceeds the adjustment voltage until the capacitor input switch control means is reset. It is preferable that it is comprised.

  In the power supply device according to the present invention, in order to use the energy stored in the auxiliary capacitor for driving the load, a discharge circuit for discharging the charge stored in the auxiliary capacitor to the output capacitor side is configured. There is a need. When using a switching element that exhibits bidirectionality when turned on as a switch for turning on the capacitor, the auxiliary capacitor can be discharged to the output capacitor side through the switch for turning on the capacitor while the switch for turning on the capacitor is on. When using a switching element that exhibits unidirectionality when turned on as a capacitor input switch, it is necessary to provide means for discharging the charge accumulated in the auxiliary capacitor to the output capacitor side separately from the capacitor input switch. . In order to use the energy stored in the auxiliary capacitor for driving the load even after the switch for turning on the capacitor is turned off, a switching element showing bidirectionality when turned on is used as the switch for turning on the capacitor. However, it is necessary to separately provide means for discharging the charge accumulated in the auxiliary capacitor to the output capacitor side.

  Therefore, in a preferred aspect of the present invention, a rectifying element is provided to connect between the auxiliary capacitor and the output capacitor so as to allow the electric charge accumulated in the auxiliary capacitor to be discharged to the output capacitor side.

  If the rectifying element as described above is provided, it is possible to supply power to the load by discharging from the auxiliary capacitor to the output capacitor side even after the switch for turning on the capacitor is turned off after the engine is stopped. . In addition, since the discharge can be performed from the auxiliary capacitor to the output capacitor through the rectifying element, a switching element that exhibits unidirectionality when turned on can be used as a capacitor charging switch.

  In a preferred aspect of the present invention, the capacitor input switch is constituted by a MOSFET. Since the MOSFET has bidirectionality when it is turned on (current can flow from the drain side to the source side and from the source side to the drain side), when the MOSFET is in the on state, the auxiliary capacitor is transferred to the output capacitor side. Can be discharged through the MOSFET. Further, the parasitic diode formed between the drain and source of the MOSFET can function as the rectifying element, so that the power supply from the auxiliary capacitor can be continued even after the MOSFET is turned off.

  According to the present invention, when the internal combustion engine is started, the auxiliary capacitor is kept disconnected from the output capacitor until the voltage between the output terminals of the regulator reaches the set voltage, and the voltage between the output terminals of the regulator reaches the set voltage. After that, the auxiliary capacitor is connected in parallel to the output capacitor. Therefore, when starting the engine, the voltage charged between the output terminals of the regulator is the only output capacitor and the voltage between the output terminals of the regulator The start-up of the engine can be made faster, and the start-up of the engine can be improved by speeding up the rise of the power supply voltage applied to the essential electrical components that are essential to drive the internal combustion engine.

  In addition, according to the present invention, since the auxiliary capacitor is connected in parallel to the output capacitor after the voltage between the output terminals of the regulator reaches the set voltage, the electrostatic capacitance of the capacitor charged by the voltage between the output terminals of the regulator. The capacitance can be increased to store a sufficient amount of energy in the capacitor. Therefore, it is possible to secure a sufficiently long time to supply power to the load after the internal combustion engine is stopped and the output of the generator is stopped. When the microprocessor is included in the essential electrical components, It is possible to make the processor perform the processing when the engine is stopped without any trouble.

  Therefore, according to the present invention, it is possible to ensure a sufficiently long time for the microprocessor to perform the engine stop process when the engine is stopped, without impairing the startability of the engine. Even when the process is complicated and requires a long time to complete the engine stop process, the power supply device for the internal combustion engine can be configured so as not to depend on the battery.

1 is a circuit diagram schematically showing a configuration of an embodiment of a power supply device for an internal combustion engine according to the present invention. It is the flowchart which showed an example of the algorithm of the process which a control part performs in embodiment of FIG. In the embodiment shown in FIG. 1, when the control unit executes the process shown in FIG. 2, the waveform of the voltage output from the regulator and the waveform of the voltage output from the regulator in the conventional internal combustion engine power supply device are shown. It is the wave form diagram shown with the full wave rectification waveform at the time of the no-load of a generator. It is the flowchart which showed the other example of the algorithm of the process which a control part performs in embodiment of FIG. In the embodiment shown in FIG. 1, when the control unit performs the processing shown in FIG. 4, the waveform of the voltage output from the regulator and the waveform of the voltage output from the regulator in the conventional internal combustion engine power supply device Is a waveform diagram showing the full wave rectification waveform when the generator is unloaded. It is the circuit diagram which showed the circuit structure of other embodiment of the power supply device for internal combustion engines which concerns on this invention. It is the flowchart which showed an example of the algorithm of the process which a control part performs in embodiment of FIG. It is the flowchart which showed the other example of the algorithm of the process which a control part performs in embodiment of FIG. It is the circuit diagram which showed the circuit structure of the conventional power supply device for internal combustion engines. FIG. 10 is a graph schematically showing output characteristics obtained when the capacitance of the output capacitor is set to a necessary minimum size and sufficiently large in the internal combustion engine power supply device shown in FIG. 9. .

Embodiments of an internal combustion engine power supply apparatus according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 shows an example of the hardware configuration of a power supply device for an internal combustion engine according to the present invention. In the figure, 1 is an AC generator driven by an internal combustion engine, 2 is various loads including essential electrical components necessary for operating the internal combustion engine, and 3 is an AC voltage output from the generator 1 as an input. A regulator 4 for outputting a regulated DC voltage applied to the load 2 is an output capacitor connected between output terminals of the regulator 3. In the present embodiment, as the AC generator 1, a known magnet generator including a magnet rotor having a rotating field composed of a permanent magnet and a stator in which a power generation coil is wound around an armature core is used. It has been.

  The regulator 3 includes input terminals a and b to which the output of the generator 1 is input, a positive output terminal c and a negative output terminal d connected to various loads 2, and diodes (rectifier elements) D1 and D2 on the upper side of the bridge. A full-bridge type full-wave rectifier circuit in which the lower side of the bridge is configured by diodes D3 and D4, and a voltage adjustment element connected in reverse parallel to the diodes D3 and D4 that configure the lower side of the bridge of the rectifier circuit. DC power is output from the output terminals c and d when the voltage between the output terminals detected by detecting the voltage between the output terminals of the regulator and the voltage between the output terminals c and d is less than the adjustment voltage. The control unit 302 that controls the thyristors S1 and S2 to stop the output of DC power when the detected output terminal voltage is equal to or higher than the adjustment voltage. It is configured Ri. In this embodiment, the negative output terminal d of the regulator is grounded.

  In the present embodiment, the control unit 302 includes a microprocessor, and various control means are configured by causing the microprocessor to execute a predetermined program. The microprocessor constituting the control unit 302 operates by obtaining a power supply voltage from a constant voltage power supply circuit (not shown) that converts the voltage between the output terminals of the regulator into a constant DC voltage. The microprocessor constituting the control unit 302 may be provided exclusively for controlling the power supply device, or may be a microprocessor provided in an ECU that controls the internal combustion engine.

  The control unit 301 has a port A1 to which a voltage Vp between the output terminals c and d (voltage between output terminals) Vp is input, and ports A2 and A3 connected to the gates of the thyristors S1 and S2, and through the port A1. When the detected voltage Vp becomes equal to or higher than the set adjustment voltage, a voltage adjustment operation is performed by simultaneously applying trigger signals from the ports A2 and A3 to the thyristors S1 and S2.

  Although the above configuration is the same as that of the conventional power supply device, in the present embodiment, the auxiliary capacitor 6 is connected between the output terminals c and d of the regulator 3 via the capacitor charging switch 5, and the output terminal of the regulator 3. The capacitor input switch 5 is controlled in accordance with the voltage between the output terminals of the regulator so that the capacitor input switch 5 is turned on when the inter-voltage becomes equal to or higher than the set voltage set lower than the adjustment voltage. Capacitor input switch control means is provided in the control unit 302.

  In this embodiment, a capacitor input switch 5 is configured by a MOSFET (field effect transistor) F1 having a drain connected to the positive output terminal c of the regulator and a gate connected to the port A4 of the control unit 302, and the source of the MOSFET And an auxiliary capacitor 6 is connected between the negative output terminal (ground) d of the regulator 3.

  Further, in the present embodiment, in order to configure a power supply path from the auxiliary capacitor 6 to the load side (discharge path of the auxiliary capacitor) when the capacitor input switch is turned off, one end of the auxiliary capacitor 6 on the positive polarity side and the regulator A rectifying element having a forward direction from the auxiliary capacitor 6 to the positive output terminal c is provided between the positive output terminal 3 and the positive output terminal c. In the present embodiment, the rectifying element is composed of a parasitic diode Dp formed between the drain and source of the MOSFET F1.

  The microprocessor constituting the control unit 302 executes a predetermined program stored in the non-volatile memory, so that when the voltage between the output terminals of the regulator is less than the adjustment voltage, the microprocessor supplies the load from the output terminals c and d. Output control means for controlling the thyristors S1 and S2 with respect to the voltage between the output terminals of the regulator so that the output of the DC power is stopped when the voltage between the output terminals is equal to or higher than the adjustment voltage, Capacitor input switch control means for controlling the capacitor input switch so that the capacitor input switch is turned on when the voltage between the output terminals becomes equal to or higher than a set voltage set lower than the adjustment voltage. The switch control means for turning on the capacitor used in the present embodiment is a period until the switch control means for turning on the capacitor is reset after the voltage between the output terminals of the regulator once exceeds the adjustment voltage (for example, the power supply of the microprocessor). Until the capacitor is turned off).

  The output control means simultaneously applies a trigger signal to the thyristors S1 and S2 when the voltage Vp between the output terminals of the regulator becomes equal to or higher than the set adjustment voltage, and when the voltage Vp becomes less than the adjustment voltage, the thyristor S1 and It is configured to stop the trigger of S2. When a trigger signal is given to the thyristors S1 and S2, among these thyristors, a thyristor to which a forward voltage is applied between the anode and the cathode is turned on, and the output of the generator 1 is connected to the thyristor S1 and the diode D4. The output of the generator is stopped by short-circuiting through a series circuit or a series circuit of thyristor S2 and diode D3.

  When the voltage Vp between the output terminals of the regulator becomes less than the adjustment voltage, the supply of the trigger signal to the thyristors S1 and S2 is stopped. When the supply of the trigger signal to the thyristors S1 and S2 is stopped, the thyristor that has been in the ON state until then at the zero crossing point of the output voltage of the generator that comes immediately after that becomes the OFF state, and the output of the generator Is released and the regulator output is restored. When the voltage between the output terminals of the regulator is equal to or higher than the adjustment voltage, the voltage between the output terminals c and d of the regulator is maintained at a voltage near the adjustment voltage by repeating these operations. When the voltage between the output terminals of the regulator is less than the adjustment voltage, the adjustment operation is not performed, so that the full-wave rectified output of the generator is output from the output terminals c and d.

  The adjustment voltage is appropriately set according to the rated voltage of the load connected between the output terminals of the regulator 3. How to set the adjustment voltage is a design problem.

  The capacitor charging switch control means formed by the control unit 302 is configured such that the voltage between the output terminals of the regulator 3 becomes equal to or higher than the set voltage as the output voltage of the generator 1 rises after the start operation of the internal combustion engine is started. Sometimes, the auxiliary capacitor 6 is connected in parallel to the output capacitor 4 by turning on the MOSFET F1 (capacitor charging switch).

  Therefore, in this embodiment, the auxiliary capacitor 6 is kept disconnected from the output capacitor 4 until the voltage between the output terminals of the regulator 3 reaches the set voltage when the internal combustion engine is started, and the voltage between the output terminals of the regulator 3 is reduced. After reaching the set voltage, the auxiliary capacitor 6 is connected in parallel to the output capacitor 4.

  In order to improve the startability of the engine by using only the output capacitor 4 as the capacitor charged by the voltage between the output terminals of the regulator at the start of the internal combustion engine, and by making the rise of the voltage between the output terminals of the regulator faster. The voltage is set to be equal to or higher than the voltage between the output terminals of the regulator 3 when the essential electrical components start to operate. However, after the output voltage of the generator 1 rises and the regulator enters the state of performing the voltage adjustment operation, the regulator In order to be able to charge both the output capacitor and the auxiliary capacitor by the voltage between the output terminals, it is preferable to set it lower than the regulator adjustment voltage. The above set voltage value ensures that the engine stop process to be performed by the microprocessor of the ECU that controls the internal combustion engine when the internal combustion engine is stopped does not depend on the battery and without sacrificing the startability of the engine. It is set to a value suitable for achieving the object of the present invention that allows it to be completed. The value of this set voltage can be selected from various values such as the capacitance of the output capacitor and auxiliary capacitor, the value of the voltage for operating the essential electrical components, and the time required for the microprocessor to perform processing when the engine is stopped. Although it is determined as appropriate according to the parameters, the value of the set voltage can be determined based on experiments.

  Also, the capacitance of the output capacitor 4 is such that when the engine is started, the voltage across the output terminals of the regulator can be raised sufficiently fast to ensure that the engine is started. It is set to a minimum value necessary for performing the function to be performed by the capacitor (for example, a minimum value required to keep the ripple included in the voltage between the output terminals of the regulator 3 within an allowable range). Also, the capacitance of the sum of the capacitance of the auxiliary capacitor 6 and the capacitance of the output capacitor 4 is sufficient for the time required for the microprocessor to complete the engine stop process after the engine is stopped. The capacitance of the auxiliary capacitor is sufficiently large so that the voltage between the output terminals is as large as necessary to keep the voltage between the output terminals above the necessary level (the level necessary to keep the microprocessor in operation). Set to value.

  In the present invention, the voltage regulating element (thyristor in this embodiment) and the capacitor input switch are controlled with respect to the voltage between the output terminals of the regulator. The “voltage between the output terminals of the regulator” used for these controls is the voltage. Any voltage to ground (voltage between the power supply line and ground) detected at any point in the power supply line from the positive output terminal of the conversion circuit 301 to the positive terminal of the load 2 via the positive output terminal c of the regulator may be used. The voltage is not limited to the voltage directly detected between the output terminals c and d of the regulator.

  When configured as described above, after the start operation of the engine is started, until the voltage between the output terminals of the regulator 3 reaches at least the lower limit value of the voltage necessary for operating the essential electrical components, Since only the output capacitor 4 can be charged by the voltage between the output terminals of the regulator, the power supplied to the essential electrical components can be obtained by setting the capacitance of the output capacitor 4 to the minimum necessary value. The start-up of the engine can be improved by increasing the voltage rising speed.

  Further, after the voltage between the output terminals of the regulator 3 reaches the set voltage, the auxiliary capacitor 6 is connected in parallel to the output capacitor 4, and the capacitance of the auxiliary capacitor 6 is added to the capacitance of the output capacitor 4. Therefore, a sufficiently large amount of energy can be stored in the capacitor connected to the output terminal of the regulator. Therefore, after the internal combustion engine is stopped and the output of the generator is stopped, the time for supplying power to the load 2 can be made sufficiently long, which hinders the processing at the time of engine stop for the microprocessor of the ECU that controls the internal combustion engine. Can be done without.

  Therefore, with the above-described configuration, the ECU 2 continues to supply voltage to the load 2 for a sufficiently long time for the ECU microprocessor to perform processing at the time of engine stop without impairing the startability of the engine. Even when it takes a long time for the ECU microprocessor included in the load 2 to complete the engine stop process, the system driven by the internal combustion engine may be a system whose power source does not depend on the battery. it can.

  Referring to FIG. 2, there is shown a flowchart showing an example of a task algorithm executed by the microprocessor in order to configure the output control means and the capacitor input switch control means provided in the control unit 302. In FIG. 2, Vp represents the voltage between the output terminals of the regulator detected at an appropriate place on the power supply line, and VccOn is the voltage between the output terminals of the regulator to determine whether or not to turn on the capacitor input switch. The set voltage compared with is shown. Vsc represents a regulator adjustment voltage.

  The task shown in FIG. 2 is activated at regular intervals. When the task shown in FIG. 2 starts, first, in step S01, the regulator output terminal voltage Vp is compared with the set voltage VccOn. As a result, when it is determined that the relationship of Vp <VccOn is established, this task is finished without doing anything. If it is determined in step S01 that the relationship of Vp <VccOn is not established, the process proceeds to step S02 to determine whether or not the relationship of VccOn ≦ Vp <Vsc is established. As a result, when it is determined that the relationship of VccOn ≦ Vp <Vsc is established, the process proceeds to step S03 to turn on the MOSFET F1 and not to trigger the thyristors S1 and S2, thereby ending this task. If it is determined in step S02 that the relationship of VccOn ≦ Vp <Vsc is not established (Vp ≧ Vsc), the process proceeds to step S04 to trigger the thyristors S1 and S2 to short-circuit the generator output. This task is terminated after the voltage adjustment operation to be performed is performed.

  In the case of the algorithm shown in FIG. 2, the capacitor input switch is controlled so that the capacitor input switch is turned on when the voltage between the output terminals of the regulator becomes equal to or higher than the set voltage in steps S01 to S03. Capacitor switch control means is configured. Further, the output control means is constituted by steps S02 to S04.

  When the capacitor control switch control means and the output control means are configured by causing the microprocessor to execute the task shown in FIG. 2, the voltage between the output terminals of the regulator is set after the engine starting operation is started. Until the voltage VccOn is reached, the MOSFET F1 is kept in the OFF state, so that the auxiliary capacitor 6 is kept in a state disconnected from the output capacitor. When the voltage between the output terminals of the regulator becomes equal to or higher than the set voltage VccOn, the MOSFET F1 is turned on, so that the auxiliary capacitor 6 is connected to the output capacitor 4 in parallel. The thyristors S1 and S2 are kept off when the voltage between the output terminals of the regulator 3 is less than the adjustment voltage Vsc, and the thyristors S1 and S2 are triggered when the voltage between the output terminals of the regulator 3 becomes equal to or higher than the adjustment voltage Vsc. Thus, the voltage between the output terminals of the regulator 3 is controlled so as not to exceed the adjustment voltage.

  FIG. 3 shows the transition of the voltage of each part observed at the time of starting when the thyristors S1 and S2 and the MOSFET F1 of the regulator are controlled as described above, taking time t on the horizontal axis. In the figure, a shows a full-wave rectification waveform when the generator 1 is unloaded, and b shows one capacitor having a capacitance equal to the sum of the capacitance of the output capacitor and the capacitance of the auxiliary capacitor. The voltage between the output terminals of the regulator obtained when connected between the output terminals of the regulator (prior art) is shown. Further, c represents a change in the voltage between the output terminals of the regulator obtained in the embodiment of the present invention, and d represents a change in the voltage obtained across the auxiliary capacitor 6 in the embodiment of the present invention.

  The electrostatic capacity of the output capacitor 4 used in the example shown in FIG. 3 is set to be sufficiently small so that the rise of the voltage between the output terminals of the regulator is quick at the start of the engine, and the output capacitor 4 and the auxiliary capacitor 6 When connected in parallel, the time required to maintain the voltage between the output terminals of the regulator after the engine is stopped to maintain the microprocessor in an operating state is used to allow the microprocessor to perform processing when the engine is stopped. The capacitances of the output capacitor 4 and the auxiliary capacitor 6 are set so as to be longer than the required time.

  In the case of the prior art, a capacitor having a sufficiently large capacitance is connected between the output terminals of the regulator so that the microprocessor can perform processing when the engine is stopped after the internal combustion engine is stopped. Therefore, the voltage between the output terminals of the regulator 3 rises relatively slowly as shown by the curve b in FIG. 3, and the level of the voltage between the output terminals of the regulator operates the essential electrical components at time t2. Therefore, when the required level Vs is reached, the essential electrical components become operable and the engine is started.

  On the other hand, according to the embodiment of the present invention, since the capacitance of the output capacitor 4 is smaller than that according to the prior art, the voltage between the output terminals of the regulator 3 is as shown by a curve c in FIG. The voltage rises quickly, and at time t1, which is faster than time t2, the level of the voltage between the output terminals of the regulator reaches the level Vs necessary for operating the essential electrical component, and the essential electrical component becomes operable. Therefore, according to the present invention, when the engine is started manually by using a recoil starter or a kick starter, the startability of the engine can be improved.

  In the above embodiment, when the voltage Vp between the output terminals of the regulator reaches the set voltage VccOn at time t3, the MOSFET F1 (capacitor switching switch) is turned on and the auxiliary capacitor 6 is connected between the output terminals c and d. Connected. As a result, the electrostatic capacity charged by the voltage between the output terminals of the regulator increases, and therefore, between the output terminals of the regulator for a sufficient period of time necessary for the microprocessor to perform processing when the engine is stopped after the engine is stopped. The voltage can be held at a level necessary to keep the microprocessor operational.

  At time t3, when the MOSFET F1 is turned on and the auxiliary capacitor 6 is connected between the output terminals of the regulator, the capacitance between the output terminals of the regulator 3 increases rapidly, so that the curve c in FIG. As can be seen, a drop occurs in the voltage between the output terminals of the regulator 3. There is no particular problem if the voltage drop does not cause the voltage across the output terminals of the regulator to be lower than the lower limit (allowable lower limit voltage) of the voltage range necessary to keep the essential electrical components in operation. However, if the voltage between the output terminals of the regulator may fall below the allowable lower limit voltage when the auxiliary capacitor is turned on, the operation of essential electrical components may be adversely affected. Even if the voltage between the output terminals of the regulator drops immediately after the adjustment, it is preferable that the voltage does not fall below the lower limit value of the voltage range necessary for maintaining the essential electrical component in the operating state. .

  According to the above embodiment, when the capacitor charging switch 5 is turned on and the auxiliary capacitor is switched on, a relatively large drop occurs in the voltage between the output terminals of the regulator. Therefore, by changing the algorithm of the task to be executed by the microprocessor and changing the control content by the switch control means for switching on the capacitor, the output of the regulator in the process of switching on the auxiliary capacitor without changing the hardware configuration It is possible to prevent a large drop in the voltage between the terminals.

  FIG. 4 shows an example of a task algorithm executed by the microprocessor in order to prevent a large drop in the voltage between the output terminals of the regulator in the process of inserting the auxiliary capacitor. In the present embodiment, when the capacitor input switch control means turns on the capacitor input switch 5 and the voltage between the output terminals of the regulator 3 becomes less than the allowable lower limit voltage VccOff set lower than the set voltage VccOn. The switch-off control for turning off the capacitor input switch 5 and the switch-on switch 5 is turned on when the voltage between the output terminals of the regulator 3 becomes equal to or higher than the set voltage VccOn. Further, on-return control for setting the state is performed. Also in the present embodiment, the capacitor input switch control means includes the capacitor input switch until the capacitor input switch control means is reset after the voltage between the output terminals of the regulator once exceeds the adjustment voltage. Configured to remain on. The parameters VccOn (set voltage), VccOff (allowable lower limit voltage), and Vsc (adjustment voltage) are set so as to satisfy the relationship of VccOff <VccOn <Vsc.

  The task shown in FIG. 4 is activated at regular intervals. When this task is started, first, in step S01, the voltage Vp between the output terminals of the regulator is compared with an allowable lower limit voltage VccOff set lower than the set voltage VccOn. As a result, when the relationship of Vp <VccOff is satisfied (when the voltage between the output terminals of the regulator is less than the allowable lower limit voltage VccOff), the process proceeds to step S02 to determine whether or not the flag F1_On_Keep_F is 0. As a result, when it is determined that the flag F1_On_Keep_F is 0, the process proceeds to step S03 to turn off the MOSFET F1 and terminate this task. If the flag F1_On_Keep_F is not 0, do nothing. finish.

  When it is determined in step S01 that the relationship of Vp <VccOff is not satisfied (when it is determined that the voltage between the output terminals of the regulator is equal to or higher than the allowable lower limit voltage), the process proceeds to step S04 and VccOff ≦ Vp < It is determined whether the VccOn relationship is established. As a result, when it is determined that the relationship of VccOff ≦ Vp <VccOn is established, this task is terminated without doing anything below, and when it is determined that the relationship of VccOff ≦ Vp <VccOn is not established (regulator When the output terminal voltage Vp becomes equal to or higher than the set voltage VccOn), the process proceeds to step S05.

  In step S05, it is determined whether or not a relationship of VccOn ≦ Vp <Vsc is established. As a result, when it is determined that the relationship of VccOn ≦ Vp <Vsc is established (when the voltage Vp between the output terminals of the regulator is equal to or higher than the set voltage VccOn and within the range of less than the adjustment voltage Vsc), the process proceeds to step S06. The MOSFET F1 is turned on, the auxiliary capacitor is turned on, and this task is terminated while the thyristors S1 and S2 are left in the off state without being triggered. When it is determined in step S05 that the relationship of VccOn ≦ Vp <Vsc is not established (when the voltage Vp between the output terminals of the regulator is equal to or higher than the adjustment voltage Vsc), the process proceeds to step S07 and the thyristors S1 and S2 Trigger the voltage adjustment operation. In step S07, the MOSFET F1 is turned on, and a flag F1_On_Keep_F indicating that the condition for holding the MOSFET F1 in the on state is satisfied is set to 1, and this task is ended. The above-mentioned steps S01 to S07 constitute a capacitor input switch control means. Further, the output control means is constituted by steps S05 to S07.

  When the algorithm shown in FIG. 4 is used, the allowable lower limit voltage in which the voltage between the output terminals of the regulator 3 is set lower than the set voltage VccOn with the capacitor charging switch 5 turned on in steps S01 to S03. Switch-off control is performed to turn off the capacitor insertion switch 5 when VccOff becomes less than VccOff, and the voltage between the output terminals of the regulator 3 is obtained by performing switch-off control in steps S01, S04, S05, and S06. Since the on-return control is performed to turn on the capacitor charging switch 5 when the voltage becomes equal to or higher than the set voltage VccOn, the voltage between the output terminals of the regulator falls below the allowable lower limit voltage VccOff in the process of turning on the auxiliary capacitor. Can be prevented.

  FIG. 5 shows voltage waveforms at various parts observed when the control shown in FIG. 4 is performed. In the figure, a shows a full-wave rectification waveform when the generator 1 is unloaded, and b shows a regulator having a capacitance equal to the sum of the capacitance of the output capacitor and the capacitance of the auxiliary capacitor. The voltage between the output terminals of the regulator obtained when connecting between the output terminals (conventional technology) is shown. Further, c represents a change in the voltage between the output terminals of the regulator obtained when the control of FIG. 4 is performed, and d represents a change in the voltage obtained at both ends of the auxiliary capacitor 6. As can be seen from the curve c, the voltage between the output terminals of the regulator does not fall below the allowable lower limit voltage VccOff in the process of inserting the auxiliary capacitor, so the voltage between the output terminals of the regulator increases toward the adjustment voltage. In the process, it is possible to prevent the load from being greatly reduced and adversely affecting the load. When the control of FIG. 4 is performed, the voltage at both ends of the auxiliary capacitor 6 is changed while the switch-off control and the switch-on return control are alternately performed as shown by the curve d in FIG. Until the voltage between the output terminals of the regulator becomes equal to or higher than the adjustment voltage and the MOSFET F1 is held in the ON state.

  In the example shown in FIG. 5, the MOSFET F1 is turned off when the voltage between the output terminals of the regulator becomes lower than the set voltage VccOn. However, after the charging of the auxiliary capacitor 6 is completed, the MOSFET F1 is set. May be configured to be held in an on state. With this configuration, the charge accumulated in the auxiliary capacitor 6 can be discharged to the load side through between the drain and source of the MOSFET. Therefore, the charge accumulated in the auxiliary capacitor 6 can be reduced in voltage drop caused by the parasitic diode. Electric power can be supplied to the load by discharging to the load side without being affected.

  In the above embodiment, a short-circuit regulator is used as the regulator, but when a switching element such as a thyristor is used as a part of the elements constituting the rectifier circuit, the voltage between the output terminals of the regulator exceeds the adjustment voltage. The present invention can also be applied to the case of using an open type regulator that opens the rectifier circuit by turning off the switching element.

  FIG. 6 shows an example of the hardware configuration when an open regulator is used. The regulator 3 shown in FIG. 6 has input terminals a and b to which the output of the generator 1 is input, a positive output terminal c and a negative output terminal d to which the load 2 is connected, and a voltage adjusting element on the upper side of the bridge. The voltage conversion circuit 301 composed of a full-bridge type full-wave rectifier circuit composed of the thyristors S1 and S2 and the lower side of the bridge composed of the diodes D3 and D4, and the DC voltage between the output terminals is kept below the adjustment voltage. The control unit 302 controls the thyristors S1 and S2. The other points are configured in the same manner as the example shown in FIG.

  The control unit 302 causes the microprocessor to execute a predetermined program, thereby controlling the output of the regulator according to the voltage between the output terminals of the regulator, and the voltage between the output terminals of the regulator is equal to or higher than the set voltage. Capacitor input switch control means for controlling the capacitor input switch 5 to sometimes turn on the capacitor input switch 5 is configured. When the voltage between the output terminals c and d of the regulator 3 is less than the adjustment voltage, the output control means triggers the thyristors S1 and S2 to turn on both thyristors, thereby outputting DC power from the output terminals, When the voltage between the output terminals c and d becomes equal to or higher than the adjustment voltage, the trigger of the thyristors S1 and S2 is stopped, and the output of DC power from the regulator is stopped.

  FIG. 7 is a flowchart showing an algorithm of tasks to be executed by the microprocessor in order to configure the output control means and the capacitor input switch control means provided in the control unit 302 of FIG. The task shown in FIG. 7 is also activated at regular intervals. When this task is started, first, in step S01, the voltage Vp between the output terminals of the regulator is compared with the set voltage VccOn. As a result, when the relationship of Vp <VccOn is established, the process proceeds to step S02, triggers thyristors S1 and S2, and then ends this task. If it is determined in step S01 that the relationship of Vp <VccOn is not established, the process proceeds to step S03 to determine whether or not the relationship of VccOn ≦ Vp <Vsc is established. As a result, when it is determined that the relationship of VccOn ≦ Vp <Vsc is established, the routine proceeds to step S04, where the thyristors S1 and S2 are triggered, the MOSFET F1 is turned on, and this task is terminated. When it is determined in step S03 that the relationship of VccOn ≦ Vp <Vsc is not established (when the voltage between the output terminals of the regulator is equal to or higher than the adjustment voltage), the process proceeds to step S05 and thyristors S1, S2 This task is terminated after stopping the trigger.

  In the case of the algorithm shown in FIG. 7, the capacitor input switch is controlled to turn on the capacitor input switch when the voltage between the output terminals of the regulator becomes equal to or higher than the set voltage in steps S01 to S04. Capacitor switch control means is configured. In addition, steps S01 to S05 constitute output control means for controlling the voltage between the output terminals of the regulator to be kept below the adjustment voltage.

  Referring to FIG. 8, in the embodiment of FIG. 6, there is shown an algorithm of a task to be executed by the microprocessor in order to prevent a large drop in the voltage between the output terminals of the regulator in the process of turning on the auxiliary capacitor 6.

  The task shown in FIG. 8 is also activated at regular intervals. When this task is started, first, in step S01, the voltage Vp between the output terminals of the regulator is compared with the allowable lower limit voltage VccOff. As a result, when the relationship of Vp <VccOff is satisfied (when the voltage between the output terminals of the regulator is less than the allowable lower limit voltage VccOff), the process proceeds to step S02 to trigger the thyristors S1 and S2, and then the flag F1_On_Keep_F in step S03. Whether or not is 0 is determined. As a result, when it is determined that the flag F1_On_Keep_F is 0, the process proceeds to step S04 to turn off the MOSFET F1 and end this task. If the flag F1_On_Keep_F is not 0, do nothing. finish.

  When it is determined in step S01 that the relationship of Vp <VccOff is not established (when it is determined that the voltage between the output terminals of the regulator is equal to or higher than the allowable lower limit voltage), the process proceeds to step S05 and VccOff ≦ Vp < It is determined whether the VccOn relationship is established. As a result, when it is determined that the relationship of VccOff ≦ Vp <VccOn is established, the process proceeds to step S06, triggers the thyristors S1 and S2, and ends this task. When it is determined in step S05 that the relationship of VccOff ≦ Vp <VccOn is not established (when the voltage Vp between the output terminals of the regulator becomes equal to or higher than the set voltage VccOn), the process proceeds to step S07.

  In step S07, it is determined whether a relationship of VccOn ≦ Vp <Vsc is established. As a result, when it is determined that the relationship of VccOn ≦ Vp <Vsc is established (when the voltage Vp between the output terminals of the regulator is equal to or higher than the set voltage VccOn but lower than the adjustment voltage Vsc), the process proceeds to step S08. The MOSFET F1 is turned on, the auxiliary capacitor is turned on, the thyristors S1 and S2 are triggered, and the task is terminated.

  When it is determined in step S07 that the relationship of VccOn ≦ Vp <Vsc is not established (when the voltage Vp between the output terminals of the regulator is equal to or higher than the adjustment voltage Vsc), the process proceeds to step S09 to turn on the MOSFET F1. At the same time, a flag F1_On_Keep_F indicating that the condition for holding the MOSFET F1 in the ON state is satisfied is set to 1. In step S09, the triggering of the thyristors S1 and S2 is stopped, and the voltage adjustment operation is performed by opening the full-wave rectifier circuit. After performing step S09, this task is terminated.

  The above-mentioned steps S01 to S05 and S07 to S09 constitute a capacitor input switch control means. Output control means is constituted by steps S01, S02 and S05 to S09.

  The regulator 3 provided in the power supply device to which the present invention is applied is an input terminal to which an output of an AC generator driven by the internal combustion engine is input and an electrical component that is essential to be driven to operate the internal combustion engine. Output terminal connected to a load including electrical components, and outputs DC power from the output terminal when the voltage between the output terminals is less than the adjustment voltage, and DC when the voltage between the output terminals is equal to or higher than the adjustment voltage. Any device may be used as long as it is configured to stop the output of power, and is not limited to that shown in the above embodiment.

  In the embodiment shown in FIG. 1, thyristors S1 and S2 are used as short-circuit switch elements (voltage adjustment switch elements) for short-circuiting the output of the generator, but switching elements other than the thyristors (for example, MOSFETs) are short-circuited. It can also be used as a switch element.

  In the example shown in FIG. 1, the thyristors S1 and S2 are connected in antiparallel to the diodes D3 and D4 constituting the lower side of the bridge of the full-wave rectifier circuit, but the thyristors S1 and S2 are connected to the full-wave rectifier circuit. The diodes D1 and D2 constituting the upper side of the bridge may be connected in antiparallel.

  In each of the embodiments described above, the capacitor input switch 5 is configured by a MOSFET, but the capacitor input switch 5 may be configured by another semiconductor switching element, a relay, or the like.

DESCRIPTION OF SYMBOLS 1 AC generator 2 Load 3 Regulator 301 Voltage conversion circuit 302 Control part 4 Output capacitor 5 Capacitor switch 6 Auxiliary capacitor F1 MOSFET
S1, S2 Thyristor

Claims (5)

An input terminal to which an output of an alternator driven by an internal combustion engine controlled by an ECU equipped with a microprocessor is input, and an essential electrical component that is essential for driving the internal combustion engine are operated. An output terminal connected to the load, and outputs DC power from the output terminal when the voltage between the output terminals is less than the regulated voltage, and the DC when the voltage between the output terminals is equal to or greater than the regulated voltage. A power supply device for an internal combustion engine comprising a regulator for stopping output of power, and an output capacitor connected between output terminals of the regulator,
An auxiliary capacitor connected between the output terminals of the regulator via a capacitor charging switch;
Capacitor input switch control means for controlling the capacitor input switch so as to turn on the capacitor input switch when the voltage between the output terminals of the regulator is equal to or higher than a set voltage;
With
The set voltage is set to a voltage that is equal to or higher than the voltage between the output terminals of the regulator when the essential electrical component starts operation , and less than the adjustment voltage .
After the internal combustion engine is stopped, the voltage between the output terminals of the regulator is higher than a level necessary for maintaining the microprocessor in an operating state for a time necessary for causing the microprocessor to perform an engine stop process. The capacitance of the sum of the capacitance of the output capacitor and the capacitance of the auxiliary capacitor is set so that it can be maintained ,
A power supply device for an internal combustion engine.   The capacitor input switch control means is configured such that when the capacitor input switch is on and the voltage between the output terminals of the regulator becomes lower than an allowable lower limit voltage set lower than the set voltage, the capacitor input switch Switch-off control for turning off the capacitor, and on-return control for turning on the capacitor input switch when the voltage between the output terminals of the regulator becomes equal to or higher than the set voltage due to the switch-off control being performed. The power supply device for an internal combustion engine according to claim 1, further comprising:   The capacitor input switch control means turns on the capacitor input switch after the voltage between the output terminals of the regulator once exceeds the adjustment voltage until the capacitor input switch control means is reset. The power supply device for an internal combustion engine according to claim 1, wherein the power supply device is configured to maintain   2. A rectifying element is provided to connect between the auxiliary capacitor and the output capacitor so as to allow the electric charge accumulated in the auxiliary capacitor to be discharged to the output capacitor side. 2. The power supply device for an internal combustion engine according to 2 or 3.   5. The power supply device for an internal combustion engine according to claim 1, wherein the capacitor input switch is constituted by a MOSFET.

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