JP4670656B2 - Vehicle power supply device - Google Patents

Description

  The present invention relates to a power supply device for a vehicle.

  For example, in a motorcycle, when an engine is started, an electronic control unit or the like is activated by power supply from a battery, and the operation of the engine is started with the activation. After the engine operation is started, the generator starts generating electricity by the rotation of the engine, and the electric power generated by the generator is supplied to the electronic control unit or the like. Further, the power of the generator is appropriately supplied to the battery, and the battery is charged.

  In such a case, if the battery voltage is sufficiently high, the engine is started by power supply from the battery as described above. However, if the battery voltage is low, the engine cannot be started by power supply from the battery. Therefore, when the battery voltage is low, an initial rotation is applied to the engine by a kick operation or the like, and further, the power generation of the generator is started by the engine rotation, and then the electronic control unit or the like is started. However, when the battery voltage is low, the electric power of the generator is supplied to the battery, so that the start-up of the electronic control device is delayed and the engine startability is reduced.

  Therefore, in Patent Document 1, for example, a relay switch is provided in the middle of a path for supplying power from the generator to the battery, and the relay switch is normally opened and closed by the electronic control unit when the battery is charged. . When the engine is started, the relay switch interrupts the path between the generator and the battery, so that no power is supplied from the generator to the battery. As a result, electric power is reliably supplied from the generator to the electronic control device or the like, and a decrease in engine startability is suppressed.

  In the device disclosed in Patent Document 1, a battery and an electronic control device are connected through an ignition switch, and a generator is connected in the middle of a path connecting the battery and the electronic control device. In such a configuration, there is a possibility that a current flows into the battery by closing the ignition switch when the battery voltage is low, and a backflow prevention diode is provided to avoid this.

However, since the diode has a forward voltage, if a diode for preventing inflow is provided in the middle of the path, a voltage drop occurs. Then, when the engine is started, the voltage applied to the electronic control unit or the like by power supply from the generator or the battery decreases by the voltage drop. For this reason, when starting the engine, power cannot be efficiently supplied to the electronic control unit or the like, and the startability of the engine is reduced.
JP 2000-290619 A (FIG. 3 etc.)

  The main object of the present invention is to provide a power supply device for a vehicle that can efficiently supply electric power necessary for starting the engine at the time of starting the engine, and thus can suppress deterioration of startability of the engine. is there.

According to the first aspect of the present invention, the generator that generates power as the engine rotates and the electrical load (such as an electronic control unit) required for engine operation are connected by the first path, and the first path and the vehicle-mounted battery are Connect by two paths. The first path and the second path are opened and closed by an ignition switch. The second path is provided with a normally open relay connected in series to the ignition switch, and the normally open relay passes through the ignition switch when the ignition switch is in a closed state. the applied voltage is applied from the battery, the applied voltage is set to be closed condition that is predetermined specified value or more.

In the above configuration, the normally open relay is closed when the voltage of the battery is equal to or higher than the specified value. Therefore, when the engine is started, the ignition switch is closed. Supply is made. As a result, the electric load is operated and the engine is started. On the other hand, if the voltage of the battery is lower than the specified value, the normally open relay is not closed (is kept open), and the second path is blocked. Therefore, instead of supplying power from the battery, the electric load is operated by supplying power from the generator, and the engine is started. In this case, since the battery is disconnected from the generator, power is not supplied from the generator to the battery, and the engine is started preferentially. In addition, in this configuration, the second path (path connecting the battery, the generator and the electric load) is intermittently connected by the normally open relay . There is no inconvenience that the power supply efficiency decreases due to the voltage drop of the diode. As described above, when starting the engine, it is possible to efficiently supply electric power necessary for starting the engine, thereby suppressing a decrease in startability of the engine.
Specifically, as in the invention described in claim 2, the normally open relay is connected in series with the battery via the ignition switch, and a voltage from the battery is applied as the applied voltage. A solenoid, and a normally-open switch means provided between the ignition switch and the first path in the second path and which is closed on condition that the applied voltage is equal to or higher than the specified value. It is possible to adopt a configuration such as

In the invention according to claim 3, normally open charging switch means is provided in the middle of the charging path connecting the generator and the battery, and the charging switch means is closed according to the power generation state of the generator. . For example, when the engine speed is equal to or higher than a predetermined speed and the amount of electric power generated by the generator is large, the charging switch means is closed to charge the battery. Thereby, battery charging can be suitably performed when the battery voltage decreases.

In the invention according to claim 4, the control device closes the charging switch on condition that the voltage from the battery is less than the first predetermined voltage, and the voltage from the battery exceeds the second predetermined voltage. On the condition that the charging switch is opened . By performing opening / closing control of the charging switch means by the control device, it is possible to appropriately control the battery charging.

In the fifth aspect of the invention, when the charging switch means is in the closed state, the normally open relay provided in the second path is opened by the opening means. That is, when the charging switch means is in the closed state, the battery and the generator and the electrical load are conducted through two paths, the second path and the charging path. In this case, when the normally open relay is opened by the opening means, the second path is cut off, and the electric path can be one path, that is, only the charging path provided with the charging switch means.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In this embodiment, an application example to an engine control system for a motorcycle is described. FIG. 1 shows an outline of the system.

  In FIG. 1, an intake pipe 11 and an exhaust pipe 12 are connected to the engine 10, and a fuel injection valve 13 is provided in the intake pipe 11. An in-tank type fuel pump 15 is provided in the fuel tank 14, and the fuel in the fuel tank 14 is pumped up by the fuel pump 15, pressurized to a predetermined fuel pressure, and supplied to the fuel injection valve 13. The cylinder head of the engine 10 is provided with a spark plug 16. When a high voltage is applied to the spark plug 16 through the ignition device 17, a discharge spark is generated between the opposing electrodes of the spark plug 16. The fuel sucked into the combustion chamber is used for combustion.

  The ECU (electronic control unit) 30 serves as a central part for performing various controls of the engine 10, and various detection signals are sequentially transmitted to the ECU 30 from sensors for detecting the engine speed, engine load, and the like. Entered. The ECU 30 grasps the engine operating state based on the detection signal and controls the driving of the fuel injection valve 13, the fuel pump 15, and the ignition device 17 based on the operating state.

  FIG. 2 shows the configuration of the electrical system of this system. In FIG. 2, the AC generator 20 generates AC power by applying a driving force to a crankshaft (not shown) of the engine 10, and specifically includes a single-phase magneto generator. Has been. The engine 10 and the vehicle are operated by the electric power generated by the AC generator 20. Specifically, a lighting device 21 such as a headlight or a rear light is driven. Further, the electric power of the AC generator 20 is adjusted to a DC voltage of, for example, 14 V by the regulator 22, and then energized through a path via the ignition switch 23 and supplied to the ECU 30, the fuel pump 15, and the like. In the present embodiment, the ECU 30 and the fuel pump 15 correspond to “electric load required for engine operation”.

  The ignition switch 23 includes two switch pieces (hereinafter referred to as IG switch pieces) 23a and 23b, and the IG switch piece 23a is provided on a path (first path) connecting the AC generator 20 and the ECU 30 and the like. The path (first path) and the path (second path) connecting the battery 24 are provided with the IG switch piece 23b.

  The electric power supplied from the regulator 22 is taken into the ECU 30 via the power supply terminal T1. In the ECU 30, a capacitor 32 serving as a power storage unit is connected to the power supply terminal T <b> 1 via a diode 31, and a terminal side (that is, the cathode side of the diode 31) having a high potential in the capacitor 32 is connected to the power supply IC 33. Yes. The power supply IC 33 constitutes a power supply circuit for generating a power supply voltage VCC (for example, 5 V). A capacitor 34 is connected to the output side of the power supply IC 33.

  The microcomputer 35 constitutes a well-known arithmetic unit comprising a CPU, a ROM, and a RAM. The microcomputer 35 operates upon receiving the supply voltage VCC, and the fuel injection valve 13 and the fuel pump 15 are operated based on the engine operating state and the like. The drive of the ignition device 17 is optimally controlled. FIG. 2 shows the fuel pump 15 as an object to be controlled. When the transistor 36 is turned on by a pump drive signal output from the microcomputer 35, the fuel pump 15 is energized. That is, the drive circuit of the fuel pump 15 is configured by the transistor 36.

  In this case, the fuel pump 15 is driven by energization, the fuel in the fuel tank 14 is pumped up through the fuel pipe, pressurized to a predetermined fuel pressure, and supplied to the fuel injection valve 13. When the fuel injection valve 13 is turned on (energized) in this state, fuel injection is performed from the fuel injection valve 13.

  The battery 24 is provided with a battery voltage detector 37 for detecting the battery voltage, and a detection signal of the battery voltage detector 37 is taken into the microcomputer 35.

  In the configuration of FIG. 2, a relay 41 is provided closer to the ECU 30 than the IG switch piece 23b in the route (second route) where the IG switch piece 23b is provided. The relay 41 includes a normally open switch piece 41a connected in series to the IG switch piece 23b, and a solenoid 41b connected in series to the IG switch piece 23b and in parallel to the switch piece 41a. The switch piece 41a is closed by exciting 41b, that is, the relay 41 is turned on. At this time, when the ignition switch 23 is turned on (closed), the battery voltage is applied to the solenoid 41b. At this time, if the battery voltage (solenoid applied voltage) is equal to or higher than a predetermined relay ON voltage, the relay 41 is turned ON. The relay ON voltage is, for example, about 6 to 8V.

  A path (charging path) connecting the battery 24 side from the IG switch piece 23b in the path where the IG switch piece 23b is provided and the regulator 22 side from the IG switch piece 23a in the path where the IG switch piece 23a is provided. A normally open relay 42 is provided. The relay 42 has a normally open switch piece 42a and a solenoid 42b. When the solenoid 42 is excited by the microcomputer 35, the switch piece 42a is closed, that is, the relay 42 is turned on.

  A normally closed relay 43 is provided between the terminal on the current output side of the solenoid 41b and the ground. The relay 43 has a normally closed switch piece 43a and a solenoid 43b. When the solenoid 43b is excited by the microcomputer 35, the switch piece 43a is closed, that is, the relay 43 is turned on. In the following description, for convenience, the relay 41 is also referred to as a “first relay 41”, the relay 42 as a “second relay 42”, and the relay 43 as a “third relay 43”.

  Here, the first relay 41 is turned on / off according to the battery voltage, and the energization path to the ECU 30 or the like is switched by the turning on / off of the first relay 41. First, when the battery voltage is equal to or higher than the relay ON voltage, when the ignition switch 23 is turned ON, the first relay 41 is turned ON by applying the battery voltage to the solenoid 41b. For this reason, electric power is supplied from the battery 24 to the ECU 30 or the like via the first relay 41. Then, after the start of the microcomputer 35 and the initialization process are completed, the fuel pump 15 is driven by a pump drive signal output from the microcomputer 35. Thereafter, when the driver performs a kick operation, initial rotation is added to the engine 10, and the microcomputer 35 performs drive control of the fuel injection valve 13 and the like to start the operation of the engine 10.

  On the other hand, when the battery voltage is lower than the relay ON voltage, the first relay 41 is not turned on even when the battery voltage is applied to the solenoid 41b by turning on the ignition switch 23, so that power is supplied from the battery 24 to the ECU 30 and the like. Absent. Then, when power generation is started by the AC generator 20 with the kick start of the engine 10, electric power is supplied from the AC generator 20 to the ECU 30 and the like. At this time, since the first relay 41 is not turned on, power is not supplied to the battery 24, and power is reliably supplied from the AC generator 20 to the ECU 30 and the like. When the power supply voltage VCC reaches the activation voltage of the microcomputer 35, the microcomputer 35 is activated and initialized. After these processes are completed, the fuel pump 15 is started by the pump drive signal output from the microcomputer 35, the drive control of the fuel injection valve 13 is performed, and the operation of the engine 10 is started.

  As described above, after the engine 10 is started, the electric power generated from the AC generator 20 is sufficiently increased by the rotation of the engine 10 during operation. For this reason, the battery 24 is charged with the electric power from the AC generator 20. When the battery is charged, the second relay 42 is turned ON by the microcomputer 35, whereby the battery is charged through the second relay 42. In addition, when the battery is charged, the third relay 43 is turned on by the microcomputer 35, whereby the first relay 41 is turned off. Hereinafter, the processing of the microcomputer 35 during battery charging will be described with reference to FIG.

  In FIG. 3, first, in step S101, it is determined whether or not the engine has been started. In subsequent step S102, it is determined whether or not a condition for executing battery charging by the AC generator 20 is satisfied. At this time, if the engine rotation speed is equal to or higher than a predetermined rotation speed (for example, 4000 rpm), it is assumed that the power generation amount is sufficiently large and the battery charging execution condition is satisfied. If any of steps S101 and S102 is NO, the process is terminated as it is. If both steps S101 and S102 are YES, the process proceeds to step S103.

  In step S103, it is determined whether the second relay 42 is OFF (switch piece 42a open) and the third relay 43 is OFF (switch piece 43a closed). If YES, the process proceeds to step S104. Then, it is determined whether or not the battery 24 needs to be charged. At this time, the battery voltage is detected by the detection signal of the battery voltage detector 37, and it is determined whether or not the battery voltage is less than a predetermined voltage. In the case of YES determination, the process proceeds to step S105, where the second relay 42 is turned on (switch piece 42a is closed) and the third relay 43 is turned on (switch piece 43a is opened).

  Here, when the battery is charged through the second relay 42, the first relay 41 is turned off by turning on the third relay 43. As a result, the power feeding path from the AC generator 20 to the battery 24 is integrated into one path (path that is conducted through the second relay 42).

  In step S106, it is determined whether charging of the battery 24 is completed based on the battery voltage. In the case of NO determination in step S103, since charging of the battery 24 has already started, the process proceeds to step S106 and the same determination is performed. In the case of YES determination in step S106, the process proceeds to step S107, the second relay 42 is turned off (switch piece 42a is opened) and the third relay 43 is turned off (switch piece 43a is closed), and the charging of the battery 24 is finished. . Further, in the case of NO determination in steps S104 and S106, this process is terminated as it is.

  In the case of the conventional configuration, a diode is provided in the path between the battery 24 and the ECU 30 or the like to prevent backflow at the time of a low battery voltage, so that a voltage drop due to the diode occurs. On the other hand, in this system, since the path between the battery 24 and the ECU or the like is interrupted by the first relay 41 when the battery voltage is low, no diode is required and no voltage drop occurs. For this reason, it is possible to efficiently supply power to the ECU 30 and the like.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  A normally open first relay 41 is provided on a path (first path) connecting the AC generator 20 and the ECU 30 and the like and a path (second path) connecting the battery 24, and the first relay 41 is provided in accordance with the battery voltage. Since the relay 41 is in the closed state, when the battery voltage is low at the time of starting the engine, power can be preferentially supplied from the AC generator 20 to the ECU 30 or the like. For this reason, electric power can be reliably supplied from the AC generator 20 to the ECU 30. Further, since there is no need to install a diode for preventing backflow in the electrical path leading from the battery 24, it is possible to avoid a reduction in power supply efficiency due to a voltage drop of the diode. As described above, when the engine 10 is started, the electric power necessary for starting the engine can be efficiently supplied, and thus the startability of the engine 10 can be prevented from being lowered.

  Since the normally open second relay 42 is provided on the path (charging path) connecting the AC generator 20 and the battery 24 and the second relay 42 is closed by the ECU 30, the amount of power generated by the AC generator 20 is increased. The battery 24 can be charged by closing the second relay 42 according to the battery voltage.

  Since the first relay 41 is turned off by turning on the third relay 43 by the ECU 30, when the second relay 42 is in a closed state, a route for supplying power from the AC generator 20 to the battery 24 is changed to the first route. 2 can be integrated into a route (charging route) via the relay 42.

  In addition, this invention is not limited to the content of description of the said embodiment, For example, you may implement as follows.

  In the above embodiment, the three relays 41, 42, 43 are provided, but this is changed as shown in FIGS. In FIG. 4, the third relay 43 is omitted, and a first relay 41 and a second relay 42 are provided. In FIG. 4, when the battery voltage is equal to or higher than the relay ON voltage, the first relay 41 is turned on as the ignition switch 23 is turned on. Thereby, electric power is supplied from the battery 24 to the ECU or the like. On the other hand, when the battery voltage is lower than the relay ON voltage, even if the ignition switch 23 is turned ON, the first relay 41 is not turned ON. Further, the second relay 42 is also held off. Therefore, the AC generator 20 and the battery 24 are separated from each other. When power is supplied from the AC generator 20 to the ECU 30 or the like, power is not supplied to the battery 24. When the second relay 42 is turned on by the microcomputer 35 after the engine start is completed, the battery 24 is charged by the AC generator 20. Therefore, even in the configuration of FIG. 4, when the battery voltage is low at the time of starting the engine, power supply from the AC generator 20 to the ECU 30 or the like can be given priority.

  In FIG. 5, the second relay 42 and the third relay 43 are omitted, and only the first relay 41 is provided. In FIG. 5, when the battery voltage is equal to or higher than the relay ON voltage, the first relay 41 is turned on as the ignition switch 23 is turned on. Thereby, electric power is supplied from the battery 24 to the ECU 30 and the like. On the other hand, when the battery voltage is lower than the relay ON voltage, even if the ignition switch 23 is turned ON, the first relay 41 is not turned ON. Therefore, the AC generator 20 and the battery 24 are separated from each other. When power is supplied from the AC generator 20 to the ECU or the like, power is not supplied to the battery 24. Therefore, even in the configuration of FIG. 5, when the battery voltage is low at the time of starting the engine, power supply from the AC generator 20 to the ECU 30 or the like can be given priority.

  In the above embodiment, the power supply to the fuel pump 15 is controlled by the ECU 30, but this may be changed and the power supply to the fuel pump 15 may be performed regardless of the ECU 30. For example, the high side of the fuel pump 15 is connected to the ignition switch 23 and the low side is grounded.

It is a block diagram which shows the outline of the engine control system in this Embodiment. It is a figure which shows the structure of the electric system of this system. It is a flowchart which shows a battery charge process. It is a figure which shows the structure of the electric system of the engine control system in another form. It is a figure which shows the structure of the electric system of the engine control system in another form.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 15 ... Fuel pump, 20 ... Alternator, 23 ... Ignition switch, 24 ... Battery, 30 ... ECU, 37 ... Battery voltage detector, 41 ... First relay as switch means, 42 ... Charging switch 2nd relay as means, 43 ... 3rd relay as opening means.

Claims (5)

A generator that generates power as the engine rotates and an electrical load required for engine operation are connected by a first path, and the first path and the in-vehicle battery are connected by a second path, and the first path and the second path are connected. In the vehicle power supply device in which the route is opened and closed by an ignition switch,
The second path is provided with a normally open relay connected in series to the ignition switch ,
The normally Hirakishiki relay, the ignition switch is the applied voltage from the battery through the ignition switch is applied when in the closed state, the closed condition that the applied voltage is a predetermined specified value or more power supply apparatus for a vehicle, characterized in that a state.   The normally open relay is
  A solenoid connected in series with the battery via the ignition switch, and a voltage from the battery applied as the applied voltage;
  A normally open switch means that is provided between the ignition switch and the first path in the second path, and is in a closed state on condition that the applied voltage is not less than the specified value;
The vehicle power supply device according to claim 1, comprising: A normally open charging switch means is provided in the middle of a charging path connecting the generator and the battery, and the charging switch means is closed on condition that the rotational speed of the engine is equal to or higher than a predetermined rotational speed. The vehicle power supply device according to claim 1, wherein the vehicle power supply device is a vehicle power supply device. A control device for controlling the operation of the engine, wherein the control device closes the charging switch on condition that the voltage from the battery is less than a first predetermined voltage; 4. The vehicle power supply device according to claim 3, wherein the charging switch is opened on the condition that the voltage exceeds a second predetermined voltage . 5.   5. The vehicle electric power according to claim 3, further comprising an opening unit that opens the normally open relay provided in the second path when the charging switch unit is in a closed state. 6. Feeding device.

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