JP2006118481A - Engine start control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine start control device corresponding to a push-type start system and capable of executing engine start even when an engine ECU is inoperative.
When a start switch 12 is turned on, a power supply control ECU 10 starts supplying a power supply voltage to an engine ECU20. The engine ECU 20 energizes the starter relay 50 with the drive current Id using the start instruction signal SD as a trigger, and starts the starter 40. If the power supply voltage falls below the operating voltage lower limit value of engine ECU 20 when starter 40 is activated, engine ECU 20 is reset. When the power supply control ECU 10 detects that the operating voltage lower limit value is lower than that of the engine ECU 20 and the engine ECU 20 is reset, the power supply control ECU 10 simultaneously with the output of the start instruction signal SD in response to the second start switch 12 being turned on. The starter 40 is driven by energizing the starter relay 50 with the auxiliary drive current id by itself.
[Selection] Figure 1

Description

  The present invention relates to an engine start control device in a vehicle, and more particularly to an engine start control device capable of starting an engine even when an ECU (Electrical Control Unit) that controls engine start is inoperable. .

  The engine in a vehicle is usually started by operating an ignition switch. The ignition switch is operated by inserting an ignition key into a keyhole and rotating it to a predetermined position. The ignition switch is an OFF position for inserting / removing the ignition key, an accessory (ACC) position for energizing accessory electrical equipment such as a car audio, an ON position for energizing the engine ignition system, and for starting the engine. And an engine start (ST) position for energizing the starter. Further, the ignition key is configured to return to the on position when the driver does not apply force to maintain this position at the engine start position. On the other hand, in other positions, even if the driver releases the ignition key, the position is maintained.

  In a vehicle that performs such engine start control, generally, a starter for starting the engine is supplied with electric power from a battery mounted on the vehicle. The starter requires a large starting current in order to start the engine by performing cranking from the engine stopped state. For this reason, in an ECU that receives power supply from the battery, the supply voltage from the battery to the ECU may be lower than the operating voltage of the ECU while the starter is rotating. In such a case, the engine ECU that controls the engine start cannot operate, so the engine cannot be started.

  In order to avoid such a situation, for example, Patent Document 1 discloses an engine start control device capable of starting an engine even when an engine start system ECU is not operating.

  An engine start control device described in Patent Document 1 is connected to a motor for starting an engine, a motor control relay for switching supply / stop of electric power to the motor, and an engine start switch. The control circuit for controlling the opening and closing of the engine, the engine start switch, the control circuit, and the motor are connected, and when the excitation coil is energized from the control circuit, the engine start switch and the motor are de-energized, When the excitation coil is not energized, a normally closed relay is provided between the engine start switch and the motor.

In the above configuration, when the engine start switch is turned on in conjunction with the ignition switch being turned from the on position to the engine start position, the control circuit energizes the excitation circuit of the motor control relay, Power is supplied from the battery to the motor. Further, the control circuit energizes the excitation circuit of the normally closed relay, thereby deactivating the engine start switch and the motor. At this time, when a large amount of electric power is supplied to the motor and the supply voltage to the control circuit is temporarily reduced, the control circuit temporarily becomes inoperable, and energization of the motor control relay from the control circuit is stopped. For this reason, the motor control relay is turned off, and power supply to the motor is stopped. However, even when the normally closed relay is not energized due to the inoperability of the control circuit, the power supply to the motor can be maintained and the engine can be started because the engine start switch and the motor are energized. Can do.
JP 2002-343449 A JP 2001-86601 A

  As described above, in the conventional engine start control device, the driver holds the ignition key at the engine start position even when the engine start system ECU becomes inoperable due to a decrease in the supply voltage from the battery. The engine can be started by combining the operation to perform the energization / non-energization operation of the relay.

  Incidentally, in engine start control, recently, an engine start control device having a smart ignition function has been proposed in response to a request for improvement in operability (see, for example, Patent Document 2). The smart ignition function means that the driver performs an operation (push) on an operation unit such as a push button switch provided in the vehicle compartment when the vehicle and the key perform wireless ID collation and the correct ID is confirmed. This is a function for starting the engine. According to this, the engine can be started without the driver turning the ignition key to a predetermined position as in the prior art. Note that such an engine start control method by operating the switch is also referred to as a push-type start system.

  However, in the push-type start system, although the operability is improved, the following problems have emerged in engine startability. As described above, this occurs when the ECU of the engine start system becomes inoperable due to a voltage drop at the starter start-up. Specifically, in the push type start system, the driver only performs a single switch operation when starting the vehicle, and a series of operations for putting the conventional ignition switch into a position corresponding to OFF, ACC, ON, ST is as follows. This is done automatically by the ECU. Due to its nature, there is no operation for the driver to hold the ignition switch in a specific position. Accordingly, once the engine start system ECU becomes inoperable due to a decrease in the supplied voltage, the engine cannot be started.

  The present invention has been made to solve the above-described problems, and its object is to correspond to a push-type start system, and to reliably start the engine even when the ECU of the engine start system is inoperative. It is an object to provide an engine start control device capable of performing the above.

  According to an aspect of the present invention, there is provided an engine start control device in which an engine start switch for instructing start of an engine mounted on a vehicle and an engine start switch are turned on and an engine start instruction is issued. According to the first and second control circuits for controlling the start of the engine by receiving power from a power source mounted on the vehicle, a motor for starting the engine by receiving power from the power source, A motor driving relay that is arranged between the motor and energized by a driving current supplied from at least one of the first control circuit and the second control circuit and supplies electric power from the power source to the motor.

  Preferably, the first control circuit has a first operating voltage lower limit value that ensures a normal operation at a power supply voltage supplied from a power source, and the second control circuit has a first operating voltage lower limit value. The second operating voltage lower limit value is lower than that of the second operating voltage.

  Preferably, the first control circuit supplies a drive current in response to a first engine start instruction when the power supply voltage is equal to or higher than the first operating voltage lower limit value. When the power supply voltage falls below the first lower limit value of the operating voltage, the second control circuit supplies a drive current according to the next engine start instruction.

  Preferably, the second control circuit has detected that the first control circuit has become inoperable, and the first control circuit has become inoperable in the first engine start instruction. When detected, the storage means for storing the detection result as a history, according to the next engine start instruction, the presence or absence of history in the storage means is determined, based on the determination that there is history, Supply drive current.

  Preferably, the first control circuit includes output means for outputting a predetermined signal instructing that it is in a normal operation state. The detecting means detects that the first control circuit has become inoperable based on the fact that the output of the predetermined signal has stopped.

  Preferably, the second control circuit erases the history from the storage means in response to the first control circuit becoming operable.

  Preferably, the second control circuit stops supplying the drive current in response to the first control circuit becoming operable.

  Preferably, the second control circuit stops the supply of the drive current in response to the power supply voltage exceeding a first operating voltage lower limit value or a predetermined voltage value equal to or higher than the first operating voltage lower limit value.

  Preferably, the second control circuit stops the supply of the drive current in response to the engine speed exceeding a predetermined speed indicating that the engine has started.

  Preferably, the first and second control circuits respectively supply drive currents in response to an instruction to start the engine.

  Preferably, the second control circuit supplies a drive current for a predetermined period in response to an instruction to start the engine.

  Preferably, the predetermined period is a period relatively shorter than a period from the time when the engine start is instructed to the time when the engine is started.

  Preferably, the second control circuit supplies a drive current in response to an instruction to start the engine.

  Preferably, the second control circuit stops supplying the drive current in response to the engine being started.

  Preferably, the second control circuit receives supply of power from the power supply in response to an instruction to start the engine, and controls power supply from the power supply to the first control circuit.

  According to the present invention, even when the first control circuit of the engine starting system becomes inoperable due to a decrease in the supply voltage from the power source, the second control circuit having a lower operating voltage than the first control circuit. By driving the starter, the engine can be reliably started.

  Further, since the starter is driven by the first control circuit and the second control circuit in response to the engine start instruction, the engine can be reliably started by a single switch operation by the driver. The nature is further improved.

  Further, by adopting a configuration in which the starter is driven by the second control circuit in response to the engine start instruction, the engine can be reliably started by a single switch operation, and high convenience is realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

[Embodiment 1]
FIG. 1 is a schematic block diagram of an engine start control device according to Embodiment 1 of the present invention.

  Referring to FIG. 1, an engine start control device includes a power control ECU 10 that controls the power state of the entire vehicle electrical system, a start switch 12, an engine ECU 20 that controls start and rotation of an engine (not shown), and a power relay 30. And a starter 40, a starter relay 50, and an engine speed sensor 60.

  The start switch 12 is a switch provided in the vicinity of the driver's seat in the vehicle compartment, and is constituted by, for example, a momentary push button switch provided on the instrument panel. The start switch 12 is turned on when operated (pushed) by the driver.

  The power supply control ECU 10 is connected to a start switch 12 and a battery (not shown). The battery is mounted on a vehicle and is composed of a secondary battery such as nickel hydride. The power supply control ECU 10 is always operable by receiving power from the battery. When the start switch 12 is turned on, the power supply control ECU 10 energizes the excitation circuit of the power supply relay 30 to turn on the power supply relay 30. Then, electric power is supplied from the battery to the engine ECU 20. Further, power supply control ECU 10 outputs a start instruction signal SD for instructing engine start to engine ECU 20.

  Engine ECU 20 is connected to a battery together with another vehicle electrical system (not shown). A power supply relay 30 is provided between the battery and the engine ECU 20. The excitation circuit of the power relay 30 is energized by the power control ECU 10 as described above. When power supply relay 30 is on, engine ECU 20 and the vehicle electrical system (not shown) are electrically connected to the battery and receive power from the battery. Further, engine ECU 20 receives start instruction signal SD from power supply control ECU 10 after the start of power supply from the battery.

  Here, the engine ECU 20 has an operating voltage limit value (hereinafter, also referred to as an operating voltage lower limit value) that ensures normal operation in the supplied power supply voltage, and the power supply voltage is equal to or higher than the operating voltage lower limit value. When it is, the signal RD instructing that the normal operation is being executed is output. On the other hand, when the power supply voltage falls below this operating voltage lower limit value, engine ECU 20 becomes inoperable (hereinafter also referred to as a reset state), and accordingly, output of signal RD is also interrupted. As will be described later, power supply control ECU 10 detects this signal RD and determines whether engine ECU 20 is in an operable state or not.

  The starter relay 50 is disposed between the engine ECU 20 and the starter 40. The excitation circuit of the starter relay 50 is energized in response to the start instruction signal SD being output from the power supply control ECU 10. To energize the starter relay 50, as shown in FIG. 1, at least one of the drive current Id from the engine ECU 20 and the auxiliary drive current id from the power supply control ECU 10 is supplied to the excitation circuit. When the excitation circuit of the starter relay 50 is energized, power is supplied from the battery to the starter 40. A method for energizing the starter relay 50 will be described in detail later.

  The starter 40 rotates upon receiving power supply from the battery. The cranking of the engine is started by the rotation of the starter 40.

  The engine speed sensor 60 detects the engine speed MRNE when engine cranking starts and the engine starts rotating. Engine speed sensor 60 outputs detected engine speed MRNE to engine ECU 20.

  When the engine ECU 20 receives the engine speed MRNE from the engine speed sensor 60, the engine ECU 20 performs a coincidence comparison operation between the detected engine speed MRNE and a predetermined predetermined speed (for example, in the vicinity of the idle speed). It is determined whether the engine is in a complete explosion state based on the result. At this time, if engine speed MRNE is equal to or higher than a predetermined speed, engine ECU 20 determines that the engine is in a complete explosion state, and determines that engine start is completed.

  Further, in starter relay 50, the supply of drive current received from one or both of engine ECU 20 and power supply control ECU 10 is stopped in response to the completion of engine start. Thereby, the rotation of the starter 40 is stopped and the engine start is finished.

  In the configuration described above, the engine start control device according to the present embodiment is characterized in that the power supply to the starter relay 50 normally performed by the engine ECU 20 can also be performed from the power supply control ECU 10. Specifically, the starter 40 is normally activated by causing the engine ECU 20 to energize the excitation circuit of the starter relay 50 by using the start instruction signal SD sent from the power supply control ECU 10 as a trigger, and from the battery to the stator 40. It is executed by supplying power to the.

  However, when the battery is deteriorated or the state of charge of the battery is insufficient, when the starter 40 is started, a large amount of power is supplied from the battery to the starter 40, so that the power supply voltage supplied to the engine ECU 20 is The operating voltage lower limit value of the engine ECU 20 may be temporarily lowered. As a result, the engine ECU 20 becomes inoperable (reset state), and the subsequent engine start operation becomes impossible.

  At this time, if it is an engine start control device using a conventional ignition switch, as described above, the operation of the driver holding the ignition key at the engine start position and the relay for energizing the battery and the starter The engine can be started by combining with the circuit. On the other hand, a push-type start system that automatically performs a series of operations from turning on a vehicle to starting an engine with only one switch operation has a configuration in which a driver holds a key at a specific position. Therefore, once the engine ECU is reset, the engine cannot be started.

  Therefore, in the present embodiment, when engine ECU 20 is reset due to a decrease in power supply voltage, starter 50 is activated by another ECU having an operating voltage lower limit value lower than that of engine ECU 20. As an example of the ECU having a low operating voltage lower limit value, there is a power supply control ECU 10 shown in FIG. This is because the power supply control ECU 10 has a function of normally operating, for example, by incorporating a booster circuit so that power can be stably supplied even when the power supply voltage is low, in order to control the power supply of the entire vehicle electrical system. It depends on. Needless to say, the present invention is not limited to the power supply control ECU 10 as long as the ECU has a low-voltage operation function.

  Hereinafter, an engine start control method executed by the engine start control device of FIG. 1 will be described in detail.

  FIG. 2 is a timing chart for illustrating engine start control according to Embodiment 1 of the present invention.

  In the engine start standby state, first, as shown in (1) in the figure, the start switch 12 is turned on by one push operation (corresponding to the one-shot pulse ST in the figure) by the driver. When the power supply control ECU 10 detects that the start switch 12 is turned on, the power supply control ECU 10 energizes the excitation circuit of the power supply relay 30 and starts supplying the power supply voltage to the vehicle electrical system including the engine ECU 20. The power supply voltage Vb supplied to the vehicle electrical system at this time is substantially the same voltage level as the battery power supply voltage (for example, 12 V) as shown in (2) in the figure, and the engine ECU 20 operates. The power supply control ECU 10 is always supplied with the power supply voltage of the battery.

  Next, power supply control ECU 10 sends start instruction signal SD for instructing engine start to engine ECU 20 for a predetermined period (corresponding to (3) in the figure). The engine ECU 20 causes the starter signal 50 to flow through the excitation circuit of the starter relay 50 using the start instruction signal SD as a trigger (corresponding to (4) in the figure). As a result, the starter 40 is activated by receiving power from the battery.

  Here, it is assumed that the power supply voltage Vb supplied to the vehicle electrical system has temporarily decreased due to the supply of a large starting current to the starter 40. At this time, depending on the state of charge of the battery, as shown in (5) in the figure, the power supply voltage Vb may fall below the operating voltage lower limit value (dotted line level in the figure) of the engine ECU 20. As a result, the engine ECU 20 becomes inoperable (reset state), and the supply of the drive current Id to the excitation circuit of the starter relay 50 is stopped. Therefore, the starter 40 cannot be driven because electric power is not supplied, and the engine cannot be started. As the engine ECU 20 is reset, the output of the signal RD instructing normal operation output from the engine ECU 20 is also stopped.

  On the other hand, power supply control ECU 10 maintains the operable state even when the power supply voltage supplied from the battery is lowered, because the operation voltage lower limit value (broken line level in the figure) is lower than the operation voltage lower limit value of engine ECU 20. is doing. The power supply control ECU 10 monitors the signal RD output from the engine ECU 20, and detects that the engine ECU 20 has been reset based on the stop of the signal RD. When power supply control ECU 10 detects that engine ECU 20 has been reset from signal RD, power supply control ECU 10 stores the detection result in an internal storage circuit as a “reset history”.

  Next, on the driver side, in response to the fact that the engine has not been started by the first push operation, the second start switch 12 is operated in order to start the engine again (in the figure ( Equivalent to 6)). When detecting that the start switch 12 is turned on, the power supply control ECU 10 outputs a start instruction signal SD to the engine ECU 20 as in the first push operation (corresponding to (7) in the figure).

  Here, as described above, the power supply control ECU 10 stores, as “reset history”, that the engine ECU 20 has been reset at the time of the first push operation. Therefore, the power supply control ECU 10 drives the starter 40 by energizing the excitation circuit of the starter relay 50 by itself with the output of the start instruction signal SD based on this “reset history” (in the drawing ( Equivalent to 8)). As long as the power supply voltage of the battery is equal to or higher than the operating voltage lower limit value of the power supply control ECU 10, the starter 40 continues to rotate by receiving power supplied from the battery, and cranks the engine (corresponding to (9) in the figure).

  When the engine is cranked, the electric power supplied from the battery to the starter 40 decreases, and the power supply voltage Vb supplied from the battery to the engine ECU 20 starts to increase. When the power supply voltage Vb exceeds the operating voltage lower limit value of the engine ECU 20 (corresponding to (10) in the figure), the engine ECU 20 becomes operable again, executes ignition injection control, and starts the engine (see FIG. Middle (11) equivalent).

  The power supply control ECU 10 stops energizing the starter relay 50 when recognizing that the engine ECU 20 is operable because the voltage level of the power supply voltage supplied from the battery exceeds a predetermined voltage level. . At this time, the power supply control ECU 10 erases (clears) the “reset history” stored in the storage circuit. The predetermined voltage level is set to a predetermined voltage value higher than the operating voltage lower limit value of engine ECU 20 or the operating lower limit value of engine ECU 20 at which the engine ECU can be reliably operated.

  As described above, according to the engine start control method according to the present embodiment, in the push-type start system, even if the engine ECU 20 becomes inoperable due to a decrease in the power supply voltage, another ECU having a lower operating voltage lower limit value. Since the starter 40 is driven by this, the engine can be reliably started.

  FIG. 3 is a flowchart showing engine start control executed by the engine start control apparatus according to Embodiment 1 of the present invention.

  Referring to FIG. 3, first, when start switch 12 is turned on by a push operation by the driver (step S01), power supply control ECU 10 detects that start switch 12 is turned on (step S02).

  The power supply control ECU 10 energizes the power supply relay 30 and starts supplying power from the battery to the vehicle electrical system including the engine ECU 20 (step S03). Further, power supply control ECU 10 outputs a start instruction signal SD for instructing engine start to engine ECU 20 for a predetermined period (step S04).

  Next, the power supply control ECU 10 determines whether or not the “reset history” of the engine ECU 20 exists in the built-in memory circuit (step S05). Specifically, if the current push operation corresponds to the second push operation shown in FIG. 2, the “reset history” in the first push operation is stored in the power supply control ECU 10. It is determined that there is “history”. On the other hand, if the current push operation corresponds to the first push operation in FIG. 2, the power supply control ECU 10 has not yet stored the “reset history”, or the memory at the previous engine start has been cleared. Therefore, it is determined that there is no “reset history”.

  If it is determined in step S05 that the engine ECU 20 has no “reset history”, that is, if it is determined that the engine ECU 20 is operable, the power supply control ECU 10 does not energize the starter relay 50. In this case, engine ECU 20 energizes starter relay 50 based on start instruction signal SD (step S06). Specifically, the starter relay 50 is energized when the drive current Id from the engine ECU 20 flows through the excitation circuit. As a result, the starter 40 starts to be driven by power supplied from the battery.

  When the power supply voltage Vb supplied from the battery to the engine ECU 20 does not fall below the operating voltage lower limit value of the engine ECU 20, the engine ECU 20 is in an operable state and performs ignition control to start the engine (step S13). .

  When engine ECU 20 determines that the engine is in a complete explosion state based on detected engine speed MRNE, engine ECU 20 determines that engine start is complete and stops energization of starter relay 50.

  On the other hand, when the starter 40 is driven, if the power supply voltage Vb temporarily decreases due to power supply to the starter 40 and falls below the operating voltage lower limit value of the engine ECU 20, the engine ECU 20 becomes inoperable (reset state) ( Step S08). When power supply control ECU 10 detects that engine ECU 20 has been reset by monitoring signal RD output from engine ECU 20, it stores the detection result in the storage circuit as a “reset history” (step S09).

  Returning to step S05 again, if it is determined that the engine ECU 20 has “reset history”, that is, if it is determined that the engine ECU 20 has become inoperable due to the previous push operation, the power supply control ECU 10 energizes the starter relay 50. Is done. At this time, the starter relay 50 is also energized by the engine ECU 20 based on the start instruction signal SD output in step S04 (step S10). Specifically, power supply control ECU 10 supplies auxiliary drive current id to the excitation circuit of starter relay 50 in addition to the output of start instruction signal SD to engine ECU 20 shown in step S04. As a result, the starter relay 50 is energized, and the starter 40 starts to be driven by receiving power from the battery.

  As described above, the power supply voltage Vb supplied to the engine ECU 20 is lower than the operating voltage lower limit value of the engine ECU 20 by driving the starter 40, but gradually increases as the starter 40 rotates. When the power supply voltage Vb supplied to the engine ECU 20 exceeds the operating voltage lower limit value in step S11, the engine ECU 20 is released from the reset state and becomes operable again (step S12), and starts the engine (step S13). ). At this time, the power supply control ECU 10 stops energization of the starter relay 50 by the auxiliary drive current id in response to the engine ECU 20 being operable (step S14).

  In the present embodiment, power supply control ECU 10 determines whether or not engine ECU 20 is operable from the voltage level of the power supply voltage supplied from the battery, but in addition to this, signal RD is sent from engine ECU 20. May be determined based on the fact that the engine speed MRNE has been output or the engine speed MRNE has exceeded a predetermined engine speed indicating that the engine has started.

  In the present invention, the driver intentionally keeps pressing the start switch 12 for a period longer than the first time during the second push operation, and the power supply control ECU 10 is based on the storage of the “reset history”. Even if the auxiliary drive current id is supplied to the starter relay 50 while the start switch 12 is kept pressed, the same effect can be obtained.

  As described above, according to the first embodiment of the present invention, in the push-type start system, even when the engine ECU becomes inoperable, the engine can be reliably started.

[Embodiment 2]
According to the first embodiment, the engine start is reliably executed through at most two push operations based on the presence or absence of the “reset history” of the engine ECU 20.

  Furthermore, if the engine can be reliably started only by the first push operation, the convenience for the driver will be further improved, and it is clear that the smart ignition function inherent to the push type start system can be further enhanced.

  Therefore, the present embodiment proposes an engine start control device that can reliably start the engine by a single push operation. Since the basic configuration of the engine start control device according to the present embodiment is the same as that of the engine start control device according to the first embodiment shown in FIG. 1, detailed description thereof will not be repeated.

  FIG. 4 is a timing chart for illustrating engine start control according to Embodiment 2 of the present invention.

  In the engine start standby state, first, as shown in (1) in the figure, the start switch 12 is turned on by a push operation (corresponding to the one-shot pulse ST in the figure) by the driver. When the power supply control ECU 10 detects that the start switch 12 is turned on, the power supply control ECU 10 energizes the excitation circuit of the power supply relay 30 and starts supplying the power supply voltage to the vehicle electrical system such as the engine ECU 20. The power supply voltage Vb of the vehicle electrical system at this time is at a voltage level substantially equal to the power supply voltage of the battery as shown in (2) in the figure, and the engine ECU 20 operates.

  Next, the power supply control ECU 10 sends a start instruction signal SD for instructing engine start to the engine ECU 20 (corresponding to (3) in the figure). The engine ECU 20 causes the starter signal 50 to flow through the excitation circuit of the starter relay 50 using the start instruction signal SD as a trigger (corresponding to (4) in the figure). As a result, the starter 40 is activated by receiving power from the battery.

  Here, in the present embodiment, as indicated by (12) in the figure, the power supply control ECU 10 drives the auxiliary drive current id for a predetermined period to the excitation circuit of the starter relay 50 using the start instruction signal SD as a trigger. It is characterized by doing. The start instruction signal SD is continuously transmitted until the end of a predetermined period in which the auxiliary drive current id is driven. According to the present embodiment, starter relay 50 is energized by drive currents Id and id from both engine ECU 20 and power supply control ECU 10 in response to the engine start instruction.

  In the above configuration, as indicated by (5) in the figure, the power supply voltage Vb supplied from the battery to the engine ECU 20 is temporarily supplied to the engine ECU 20 as power is supplied to the starter 40 when the starter 40 is activated. Consider a case where the operating voltage is below the lower limit.

  In such a case, the engine ECU 20 becomes inoperable (reset state) as in the first embodiment, and stops supplying the drive current Id to the starter relay 50. However, since the auxiliary drive current id is supplied to the excitation circuit of the starter relay 50 from the power supply control ECU 10 simultaneously with the drive current Id, the energized state is maintained. Thereby, the stator 40 can continue to be driven by receiving power supply from the battery.

  Furthermore, if the voltage supplied from the battery to the engine ECU 20 gradually increases as the stator 40 is driven and exceeds the operating voltage lower limit value of the engine ECU 20 (corresponding to (13) in the figure), the engine ECU 20 It becomes operational again. When the engine ECU 20 becomes operational again, the start instruction signal SD is still sent out, so the engine ECU 20 resumes energization of the drive current Id, and even after the energization of the auxiliary drive current id is stopped, the starter 40 To crank the engine (corresponding to (14) in the figure).

  Thus, according to the present embodiment, even when engine ECU 20 once becomes inoperable due to a decrease in power supply voltage, starter 40 is driven by power supply control ECU 10, and after voltage recovery, engine ECU 20 Since the driving of the starter 40 is resumed, it is equivalent for the driver that the engine is apparently started by a single push operation, and the convenience is further improved.

  Note that the predetermined period during which the power supply control ECU 10 energizes the auxiliary drive current id is such that the engine cannot be completely started only in the energization period of the auxiliary drive current id in order to prevent overrun of the starter 40 after the engine is started. It is desirable to set a short period.

  FIG. 5 is a flowchart showing engine start control executed by the engine start control apparatus according to Embodiment 2 of the present invention.

  Referring to FIG. 5, first, when start switch 12 is turned on by a push operation by the driver (step S20), power supply control ECU 10 detects that start switch 12 is turned on (step S21).

  The power supply control ECU 10 energizes the power supply relay 30 and starts supplying power from the battery to the engine ECU 20 and other vehicle electrical systems (step S22). Further, power supply control ECU 10 outputs a start instruction signal SD for instructing engine start to engine ECU 20 (step S23).

  Here, the power supply control ECU 10 supplies the auxiliary drive current id to the excitation circuit of the starter relay 50 for a predetermined period in addition to the output of the start instruction signal SD. Further, in response to the start instruction signal SD, the drive current Id is supplied to the starter relay 50 from the engine ECU 20 (step 24). Thus, even when engine ECU 20 becomes inoperable due to a decrease in power supply voltage Vb, starter relay 50 can maintain the energized state and continue to drive starter 40.

  The power supply control ECU 10 stops energization of the auxiliary drive current id and transmission of the start instruction signal SD after the elapse of a predetermined period (step S25). At this time, the engine ECU 20 is operable again due to the increase of the power supply voltage Vb, and the energization to the starter relay 50 is resumed.

  Finally, when the engine is cranked by the rotation of the starter 40, the engine is started by ignition control by the engine ECU 20 (step S26). When the engine is in a complete explosion state and the engine start is completed, the engine ECU 20 stops energization of the drive current Id (step S27).

  As described above, according to the second embodiment of the present invention, the engine can be reliably started by only one operation by the driver, and the convenience in the push-type start system is further enhanced.

[Embodiment 3]
In the present embodiment, following the second embodiment, another configuration example of an engine start control device capable of reliably starting the engine by one push operation is proposed. Since the basic configuration of the engine start control device according to the present embodiment is the same as that of the engine start control device according to the first embodiment shown in FIG. 1, detailed description thereof will not be repeated.

  FIG. 6 is a timing chart for illustrating engine start control according to Embodiment 3 of the present invention.

  In the engine start standby state, first, as shown in (1) in the figure, the start switch 12 is turned on by a push operation (corresponding to the one-shot pulse ST in the figure) by the driver. Thereby, the power supply control ECU 10 first detects that the start switch 12 is turned on. The power supply control ECU 10 energizes the excitation circuit of the power supply relay 30 to turn it on, and starts supplying the power supply voltage to the vehicle electrical system including the engine ECU 20. The power supply voltage Vb of the vehicle electrical system at this time is at a voltage level substantially equal to the power supply voltage of the battery as shown in (2) in the figure, and the engine ECU 20 operates.

  Here, in the present embodiment, as indicated by (15) in the figure, the power supply control ECU 10 causes the excitation circuit of the starter relay 50 to perform auxiliary driving for a predetermined period, triggered by the start switch 12 being turned on. The current id is driven. That is, the starter relay 50 is energized by the drive current id of only the power supply control ECU 10 in response to the engine start instruction. This is different from the engine start control device according to the second embodiment in which the drive current is supplied from both the engine ECU 20 and the power supply control ECU 10.

  Next, as shown in (5) in the figure, the power supply voltage Vb supplied from the battery to the engine ECU 20 is temporarily changed to the operating voltage of the engine ECU 20 as power is supplied to the starter 40 when the starter 40 is activated. Consider a case where the value falls below the lower limit.

  In such a case, engine ECU 20 becomes inoperable (reset state) as in the first and second embodiments. However, the starter relay 50 is continuously driven by the auxiliary drive current id from the power supply control ECU 10, and the energized state is maintained. Thereby, the stator 40 can continue to be driven by receiving power supply from the battery.

  Furthermore, if the voltage supplied from the battery to the engine ECU 20 gradually increases as the stator 40 is driven and exceeds the operating voltage lower limit value of the engine ECU 20 (corresponding to (16) in the figure), the engine ECU 20 When the engine can be operated again and the engine is cranked according to the rotation of the starter 40, the engine is started by ignition control (corresponding to (17) in the figure). When the power supply control ECU 10 detects the engine speed MRNE from the engine speed sensor 60 and determines that the engine has been started, the power supply control ECU 10 stops energizing the starter relay 50.

  As described above, according to the present embodiment, the starter 40 is driven by the power supply control ECU having a relatively low operating voltage lower limit value relative to the engine ECU. Even when the engine becomes inoperable, the engine can be reliably started. For the driver, since the engine can be reliably started by a single push operation, the convenience is further improved.

  FIG. 7 is a flowchart showing engine start control executed by the engine start control apparatus according to Embodiment 3 of the present invention.

  Referring to FIG. 7, first, when start switch 12 is turned on by a push operation by the driver (step S30), power supply control ECU 10 detects that start switch 12 is turned on (step S31).

  The power supply control ECU 10 energizes the power supply relay 30 and starts supplying power from the battery to the engine ECU 20 and other vehicle electrical systems (step S32).

  Next, the power supply control ECU 10 energizes the auxiliary drive current id to the excitation circuit of the starter relay 50 (step 33). Thereby, even when the engine ECU 20 becomes inoperable due to the power supply voltage drop, the starter relay 50 can maintain the normal state and continue to drive the starter 40.

  Further, the engine is cranked by the rotation of the starter 40, and the engine is started by the ignition control by the engine ECU 20 (step S34). Eventually, the engine is completely detonated and the engine start is completed. When power supply control ECU 10 determines that the engine start has been completed based on engine speed MRNE, power supply control ECU 10 stops energization of auxiliary drive current id (step S35).

  As described above, according to the third embodiment of the present invention, the engine can be reliably started by only one operation by the driver, and the operability of the push-type start system can be further enhanced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic block diagram of an engine start control device according to Embodiment 1 of the present invention. It is a timing chart for demonstrating the engine starting control by Embodiment 1 of this invention. It is a flowchart which shows the engine starting control performed with the engine starting control apparatus which concerns on Embodiment 1 of this invention. It is a timing chart for demonstrating the engine starting control by Embodiment 2 of this invention. It is a flowchart which shows the engine starting control performed with the engine starting control apparatus which concerns on Embodiment 2 of this invention. It is a timing chart for demonstrating the engine starting control by Embodiment 3 of this invention. It is a flowchart which shows the engine starting control performed with the engine starting control apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

  10 power control ECU, 12 start switch, 20 engine ECU, 30 power relay, 40 starter, 50 starter relay, 60 engine speed sensor.

Claims (15)

An engine start switch for instructing start of an engine mounted on the vehicle;
First and second controls for controlling the start of the engine by receiving the supply of electric power from a power source mounted on the vehicle in response to the engine start switch being turned on and the engine start instruction being made. Circuit,
A motor for receiving power from the power source and starting the engine;
A motor drive that is arranged between the power supply and the motor, is energized by a drive current supplied from at least one of the first control circuit and the second control circuit, and supplies power from the power supply to the motor And an engine start control device. The first control circuit has a first operating voltage lower limit value in which normal operation is guaranteed in a power supply voltage supplied from the power supply,
The engine start control device according to claim 1, wherein the second control circuit has a second operating voltage lower limit value that is lower than the first operating voltage lower limit value. The first control circuit supplies the drive current in response to a first engine start instruction when the power supply voltage is equal to or higher than the first operating voltage lower limit value.
3. The engine start according to claim 2, wherein when the power supply voltage falls below the first operating voltage lower limit value, the second control circuit supplies the drive current in response to a next engine start instruction. Control device. The second control circuit includes:
Detecting means for detecting that the first control circuit has become inoperable;
Storage means for storing the detection result as a history when it is detected in the first engine start instruction that the first control circuit has become inoperable;
4. The engine start according to claim 3, wherein the presence or absence of the history in the storage unit is determined according to the next engine start instruction, and the driving current is supplied based on the determination that the history exists. Control device. The first control circuit includes output means for outputting a predetermined signal instructing that it is in a normal operation state,
5. The engine start control device according to claim 4, wherein the detection unit detects that the first control circuit has become inoperable based on the output of the predetermined signal being interrupted.   6. The engine start control device according to claim 4, wherein the second control circuit erases the history from the storage unit in response to the first control circuit becoming operable.   The engine start control device according to claim 6, wherein the second control circuit stops the supply of the drive current in response to the first control circuit becoming operable.   The second control circuit stops the supply of the drive current when the power supply voltage exceeds the first operating voltage lower limit value or a predetermined voltage value equal to or higher than the first operating voltage lower limit value. The engine start control device according to claim 7.   The second control circuit stops the supply of the drive current in response to a rotation speed of the engine exceeding a predetermined rotation speed indicating that the engine has started to start. The engine start control device described in 1.   2. The engine start control device according to claim 1, wherein the first and second control circuits respectively supply the drive current in response to an instruction to start the engine. 3.   The engine start control device according to claim 10, wherein the second control circuit supplies the drive current for a predetermined period in response to an instruction to start the engine.   The engine start control device according to claim 11, wherein the predetermined period is a period relatively shorter than a period from a time point when the engine start is instructed to a time point when the engine is started.   The engine start control device according to claim 1, wherein the second control circuit supplies the drive current in response to an instruction to start the engine.   The engine start control device according to claim 13, wherein the second control circuit stops supplying the drive current in response to the engine being started.   2. The second control circuit receives power from the power source and controls power supply from the power source to the first control circuit in response to an instruction to start the engine. 15. The engine start control device according to any one of 1 to 14.

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