JP2016130967A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device that causes a starter relay to be turned off when a microcomputer is abnormally operative, and can suppress the starter relay from being turned off even when a reset signal is output upon cranking.SOLUTION: An electronic control device comprises: a drive circuit of a starter relay; a microcomputer that outputs a control signal to the drive circuit; a microcomputer monitor unit that determines whether the microcomputer is normally operative to output a first signal; a voltage monitor unit that determines whether a power source voltage is normal to output a second signal, and when the power source voltage is not normal, outputs a reset signal to the microcomputer and the microcomputer monitor unit as the second signal; a latch circuit that retains a last control signal until a next control signal is input regardless of the reset signal to output the last control signal as a third signal; and an AND gate that outputs a logic AND of the first signal and the third signal to the drive circuit. The microcomputer monitor unit is configured to retain and output the first signal right before the reset signal is output in a reset period.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electronic control device that controls a starter motor via a starter relay.

  As an electronic control device that controls a motor via a relay, for example, a device described in Patent Document 1 is known. This electronic control device is configured to hold and output a control signal immediately before resetting to a switch constituting a relay drive circuit when the microcomputer is reset.

US Pat. No. 6,901,326

  FIG. 5 shows a schematic configuration of a conventional electronic control apparatus represented by Patent Document 1 that controls a motor via a relay. FIG. 6 shows an operation example when a power supply voltage drop occurs while the starter switch is on. In FIG. 5, the code | symbol which added 100 to the code | symbol of the element of this embodiment is provided with respect to the element common thru | or related with the element of this embodiment mentioned later.

  The electronic control device 110 shown in FIG. 5 is an electronic control device that controls the starter motor 113 via the starter relay 112. The electronic control device 110 includes a drive circuit 120, a power supply 122, a microcomputer 123, a microcomputer monitoring unit 124, a voltage monitoring unit 125, a latch circuit 126, a reset timer 127, and an AND gate 128.

  The drive circuit 120 outputs a drive signal for turning on and off the starter relay 112 to the starter relay 112. The drive circuit 120 has a switch 121 such as a MOSFET, and one end of the switch 121 is connected to a coil constituting the electromagnetic starter relay 112. The power supply 122 supplies a power supply voltage for operating the microcomputer 123 to the microcomputer 123.

  The microcomputer 123 operates in response to the supply of the power supply voltage, and outputs a control signal for controlling the drive of the drive circuit 120 based on the input from the starter switch 111. The microcomputer 123 outputs a control signal during a period in which a reset signal (described later) is not output (reset release period). In FIG. 6, the control signal with “1” added thereto is a signal for turning on the switch 121 and corresponds to turning on the starter switch 111. On the other hand, a signal with “0” added thereto is a signal for turning off the switch 121 and corresponds to turning off the starter switch 111.

  Further, the microcomputer 123 generates a test signal for monitoring the validity of its own operation and periodically outputs it to the microcomputer monitoring unit 124. The microcomputer 123 outputs a test signal during the reset release period.

  The microcomputer monitoring unit 124 determines whether the microcomputer 123 is operating normally and outputs a first signal corresponding to the determination result. Specifically, based on the test signal output from the microcomputer 123, it is determined whether the microcomputer 123 is operating normally. The microcomputer monitoring unit 124 determines whether or not the microcomputer 123 is operating normally during the reset release period, and outputs a first signal corresponding to the determination result. For example, when the microcomputer 123 is abnormal, a low level signal is output as the first signal, and when the microcomputer 123 is normal, a high level signal is output as the first signal. In addition, the microcomputer monitoring unit 124 outputs the same signal as when the microcomputer 123 is abnormal during the period in which the reset signal is output (reset period). That is, in the reset period, a low level signal is output as the first signal as shown in FIG.

  The voltage monitoring unit 125 determines whether the power supply voltage is at a normal level and outputs a second signal corresponding to the determination result. When the power supply voltage is equal to or lower than a predetermined value set in advance, a reset signal for resetting the microcomputer 123 is output to the microcomputer 123 and the microcomputer monitoring unit 124 as the second signal. A low level signal is output as a reset signal. In FIG. 6, the voltage monitoring unit 124 outputs a reset signal so that the power supply voltage decreases during the on period when the starter switch 111 is on, and the timing overlaps with a part of the on period.

  The latch circuit 126 outputs a third signal to the AND gate 128 based on the control signal output from the microcomputer 123. Regardless of the reset signal, the latch circuit 126 holds (latches) and outputs the control signal input immediately before the next control signal is input. Therefore, when the reset signal is output, as shown in FIG. 6, the control signal immediately before the reset signal is output is held and output as the third signal. In FIG. 6, a high level signal for turning on the switch 121 is held and output.

  The reset timer 127 outputs a fourth signal to the AND gate 128 based on the second signal output from the voltage monitoring unit 125. As shown in FIG. 6, the reset timer 127 starts counting when a reset signal is output as the second signal, and continues counting only during the reset period until the count value reaches a predetermined value set in advance. Then, for example, a low level signal is output as the fourth signal in order to turn off (open) the starter relay 112 until the reset signal output is stopped after the count value reaches the predetermined value. In other periods, a high level signal is output as the fourth signal to turn on the starter relay 112.

  By the way, in order to improve safety, when the microcomputer monitoring unit 124 detects an abnormality of the microcomputer 123, there is a first need to turn off the starter relay 112 and stop the starter motor 113. On the other hand, at the time of cranking by the starter motor 113, even if a reset signal is output from the voltage monitoring unit 125 due to the power supply voltage drop, the starter relay 112 is not turned off, that is, the starter motor 113 does not want to be stopped. There are needs.

  In order to meet the first need, it can be considered that the first signal output from the microcomputer monitoring unit 124 is reflected on the ON / OFF state of the switch 121, that is, input to the AND gate 128. However, as described above, when the reset signal is output from the voltage monitoring unit 125 due to the power supply voltage drop, the microcomputer monitoring unit 124 outputs the same signal (low level) as that when the microcomputer 123 is abnormal as the first signal. Output. Therefore, even when the power supply voltage decreases, the starter relay 112 is turned off and the drive of the starter motor 113 is stopped.

  For this reason, in the conventional electronic control apparatus 10, the first signal is not input to the AND gate 128 as shown in FIG. The AND gate 128 outputs a logical product of the third signal output from the latch circuit 126 and the fourth signal output from the reset timer 127 to the drive circuit 120. Specifically, the signal is output to the gate of the switch 121 (MOSFET) constituting the drive circuit 120.

  However, in such a configuration, since the first signal is not input to the AND gate 128, the above first need cannot be met. That is, the conventional electronic control device 110 cannot satisfy both the first need and the second need.

  In view of the above problems, an object of the present invention is to provide an electronic control device capable of turning off a starter relay when a microcomputer malfunctions and suppressing the starter relay from being turned off even when a reset signal is output during cranking. .

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

One of the disclosed inventions is an electronic control device that controls a starter motor (13) via a starter relay (12) based on an input from a starter switch (11).
A drive circuit (20) for driving the starter relay;
A microcomputer (23) which operates by being supplied with a power supply voltage and outputs a control signal for controlling driving of the drive circuit based on an input from the starter switch;
It determines whether the microcomputer is operating normally and outputs the first signal according to the determination result. If it is determined that the microcomputer is not operating normally, the starter relay is turned off as the first signal. A microcomputer monitoring unit (24) for outputting a signal for causing
It determines whether or not the power supply voltage is at a normal level and outputs a second signal according to the determination result. When it is determined that the power supply voltage is not at a normal level, the second signal is used to reset the microcomputer. A voltage monitoring unit (25) for outputting a reset signal to the microcomputer and the microcomputer monitoring unit;
A latch circuit (26) for outputting a third signal based on the control signal and holding and outputting the immediately preceding control signal until the next control signal is input regardless of the reset signal;
A logic circuit (28) for outputting a logical product of the first signal and the third signal to the drive circuit;
With
When the reset signal is output, the microcomputer monitoring unit holds and outputs the first signal immediately before the reset signal is output as the first signal.

  According to this, since the first signal which is the output of the microcomputer monitoring unit is input to the logic circuit, the starter relay can be turned off and the starter motor can be stopped when the microcomputer is abnormal. That is, the above first needs can be met.

  The microcomputer monitoring unit holds the first signal immediately before the reset signal is output and outputs the first signal to the logic circuit during the period in which the reset signal is output. When the first signal immediately before the reset signal is output is, for example, a high level signal indicating that the microcomputer is normal, the high level signal is held and output. As a result, the starter relay is kept on. Therefore, even if the power supply voltage decreases during cranking and a reset signal is output, the first signal does not necessarily indicate a malfunction of the microcomputer. Thereby, even if a reset signal is output at the time of cranking, it can suppress that a starter relay is turned off. As described above, according to the present invention, both the first need and the second need can be satisfied.

It is a figure which shows schematic structure of the electronic controller which concerns on this embodiment. It is a timing chart which shows the operation example when a power supply voltage fall arises while the starter switch is ON. 10 is a timing chart showing another operation example when a power supply voltage drop occurs while the starter switch is on. 10 is a timing chart showing another operation example when a power supply voltage drop occurs while the starter switch is on. It is a figure which shows schematic structure of the conventional electronic control apparatus. It is a timing chart which shows the operation example when a power supply voltage fall arises while the starter switch is ON.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a schematic configuration of the electronic control device according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 2 shows an example of operation when the power supply voltage drops while the starter switch is on. The microcomputer monitoring unit makes a normal determination before resetting, and the reset timer count value reaches a predetermined value before reset release. The case where it does not reach is shown.

  An electronic control device 10 shown in FIG. 1 is mounted on an automobile including at least an internal combustion engine (engine) as a driving source for traveling. The electronic control device 10 is an electronic control device that controls the starter motor 13 via the starter relay 12.

  The electronic control device 10 includes a drive circuit 20, a power supply 22, a microcomputer 23, a microcomputer monitoring unit 24, a voltage monitoring unit 25, a latch circuit 26, a reset timer 27, and an AND gate 28. The reset timer 27 corresponds to the timer section described in the claims, and the AND gate 28 corresponds to the logic circuit.

  The drive circuit 20 generates a drive signal for turning on and off the starter relay 12 and outputs the drive signal to the starter relay 12. The drive circuit 20 has a switch 21 such as a MOSFET, and one end of the switch 21 is connected to a coil constituting the electromagnetic starter relay 12. When the switch 21 is turned on, the coil of the starter relay 12 is energized, and accordingly the starter relay 12 is turned on (closed). Then, electric power is supplied to the starter motor 13, and cranking of the internal combustion engine is started by the starter motor 13.

  The power supply 22 supplies a power supply voltage for operating the microcomputer 23 to the microcomputer 23. The power supply voltage is a predetermined DC voltage. In this embodiment, a DC voltage supplied from an auxiliary battery (not shown) mounted on the vehicle is stepped down by the power supply 22 and supplied to the microcomputer 23. Such a power source 22 includes, for example, a switching power source and a series power source. The power supply 22 supplies a power supply voltage to the microcomputer monitoring unit 24 (not shown).

  The microcomputer 23 is a microcomputer configured with a CPU, a ROM, a RAM, a register, an I / O port, and the like. In the microcomputer 23, the CPU performs signal processing according to a control program stored in advance in the ROM, various data acquired via the bus, and the like while using a temporary storage function of the RAM or the register. Further, the signal obtained by this signal processing is output to a bus or the like. In this way, the microcomputer 23 executes various functions.

  The microcomputer 23 operates by receiving a power supply voltage from the power supply 22, and outputs a control signal for controlling the drive of the drive circuit 20 based on the input from the starter switch 11. The microcomputer 23 outputs a control signal based on at least an input from the starter switch 11. For example, at least one of an input signal from a shift switch (shift position sensor), a signal indicating the engine speed, a start permission signal from an immobilizer control device for preventing vehicle theft, an input from the starter switch 11, A control signal may be output based on the above. The microcomputer 23 outputs a control signal during a period in which a reset signal described later is not output. That is, during the period when the reset signal is output, the microcomputer 23 does not output the control signal.

  As shown in FIG. 2, the control signal with “1” added thereto is a signal for turning on the switch 21 and corresponds to turning on the starter switch 11. On the other hand, a signal with “0” added thereto is a signal for turning off the switch 21 and corresponds to turning off the starter switch 11. If the starter switch 11 is turned on during a period when the reset signal is not output, the microcomputer 23 outputs a signal for turning on the switch 21 as a control signal. Note that a period in which the reset signal is not output is hereinafter also referred to as a reset release period, and a period in which the reset signal is output is also referred to as a reset period.

  Further, the microcomputer 23 generates a test signal for monitoring the validity of its own operation and periodically outputs it to the microcomputer monitoring unit 24. For example, the microcomputer 23 generates a predetermined true / false pattern or a watchdog clear signal as the test signal. In this embodiment, a watchdog clear signal is generated as a test signal. The microcomputer 23 outputs a test signal during the reset release period and does not output a test signal during the reset period.

  The microcomputer monitoring unit 24 determines whether or not the microcomputer 23 is operating normally, and outputs a first signal corresponding to the determination result. In the present embodiment, the microcomputer monitoring unit 24 is configured as an IC (circuit) for monitoring the microcomputer 23. The microcomputer monitoring unit 24 sets a specified time for monitoring the test signal, and determines whether the microcomputer 23 is operating normally based on whether the test signal is input within the specified time. If it is determined that the microcomputer 23 is operating normally, a high level signal is output as the first signal as shown in FIG. On the other hand, when the microcomputer monitoring unit 24 determines that the microcomputer 23 is abnormal, the microcomputer monitoring unit 24 outputs a low-level signal as the first signal.

  The first signal output when the microcomputer is abnormal is a signal for setting the starter motor 13 (starter relay 12) to be controlled to a predetermined retracted state as will be described later, and is also called a fail-safe signal or a cut signal. In the present embodiment, the starter motor 13 is set in the drive stopped state as the retracted state.

  In the reset period, unlike the conventional microcomputer monitoring unit 124, the microcomputer monitoring unit 24 of the present embodiment holds and outputs the first signal immediately before the reset signal is output as the first signal. In other words, the microcomputer monitoring unit 24 holds the first signal output according to the determination result by the test signal input immediately before the test signal is input and the determination result is output as the first signal. Output. Therefore, in the reset release period, a signal corresponding to the determination result by the test signal is output as the first signal. For example, when the test signal is input within a specified time, the first signal (high level) indicating that the microcomputer 23 is normal is output. On the other hand, if the test signal is not input within the specified time, a first signal (low level) indicating that an abnormality has occurred in the microcomputer 23 is output.

  Further, the microcomputer monitoring unit 24 sets a time longer than the time t1 longer than the specified time in the other period as the specified time t2 immediately after the output of the reset signal is stopped.

  The voltage monitoring unit 25 determines whether or not the power supply voltage supplied to the microcomputer 23 is at a normal level, and outputs a second signal corresponding to the determination result. When the power supply voltage is equal to or lower than a predetermined value set in advance, a reset signal for resetting the microcomputer 23 is output to the microcomputer 23 and the microcomputer monitoring unit 24 as the second signal. As shown in FIG. 2, the voltage monitoring unit 25 outputs a low level signal as a reset signal. When the power supply voltage exceeds a predetermined value, a high level signal indicating a reset release state is output as the second signal.

  The latch circuit 26 outputs a third signal to the AND gate 28 based on the control signal output from the microcomputer 23. Regardless of the reset signal, the latch circuit 26 holds and outputs the control signal input immediately before the next control signal is input. When the reset signal is output, the microcomputer 23 is reset and the output of the control signal is stopped. However, as shown in FIG. 2, the latch circuit 26 holds the control signal (high level) immediately before the reset signal is output and outputs it as the third signal until the next control signal is input.

  The reset timer 27 outputs a fourth signal to the AND gate 28 based on the second signal output from the voltage monitoring unit 25. As shown in FIG. 2, the reset timer 27 starts counting with the input of the reset signal as a trigger, and counts up according to the internal clock. The reset timer 27 continues counting only during the reset period until the count value reaches a predetermined value Nth (see FIG. 4) set in advance. Further, the reset timer 27 outputs a low-level signal as a fourth signal to turn off (open) the starter relay 12 until the reset signal output is stopped after the count value reaches a predetermined value. Output. For other periods, a high level signal is output as the fourth signal to turn on the starter relay 12.

  As shown in FIG. 2, when the reset is released before the count value reaches the predetermined value, the count value is cleared. In the reset cancellation period, the count value is cleared, and the reset timer 27 outputs a high-level signal as a fourth signal to turn on (close) the starter relay 12.

  The AND gate 28 outputs a logical product of the first signal output from the microcomputer monitoring unit 24, the third signal output from the latch circuit 26, and the fourth signal output from the reset timer 27 to the drive circuit 20. Output. Specifically, the signal is output to the gate of the switch 21 (MOSFET) constituting the drive circuit 20.

  The AND gate 28 outputs a high level signal indicating that the microcomputer is normal, the third signal outputs a high level signal for turning on the switch 21, and the fourth signal is a high level signal. In order to turn on the switch 21, a high level signal is output. When a high level signal is output from the AND gate 28, the switch 21 is turned on, and accordingly, the starter relay 12 is also turned on (opened). In other cases, the AND gate 28 outputs a low level signal, thereby turning off the switch 21.

  Next, another example of operation when a power supply voltage drop occurs will be described with reference to FIG. FIG. 3 shows another example of operation when the power supply voltage drops while the starter switch is on. The microcomputer monitoring unit 24 makes an abnormality determination before resetting, and the count value of the reset timer 27 reaches a predetermined value before the reset is released It shows the case where it does not reach. The test signal, the output of the microcomputer monitoring unit 24, and the output of the AND gate 28 are different from those in FIG. The power supply voltage, voltage monitor output, starter switch, control signal, latch circuit output, reset timer count value, and reset timer output are the same as in FIG.

  As shown in FIG. 3, no test signal is output from the microcomputer 23 during the reset release period T1. For this reason, the microcomputer monitoring unit 24 cannot detect the test signal within the specified time, and outputs a low-level signal indicating a microcomputer abnormality as the first signal.

  When the starter switch 11 is turned on during the reset release period T1 and then the power supply voltage decreases, the voltage monitoring unit 25 outputs a reset signal (low level) as the second signal, and the reset period T2 is entered. In the reset period T2, the microcomputer monitoring unit 24 holds and outputs the first signal immediately before the reset signal is output as the first signal, that is, the low level signal.

  When the power supply voltage is restored, the reset is released and the reset release period T3 is entered. In the reset release period T3, a test signal is periodically output from the microcomputer 23. The microcomputer monitoring unit 24 detects a test signal within a specified time and outputs a high level signal indicating that the microcomputer 23 is normal as a first signal.

  Thus, even when the first signal immediately before the reset period indicates an abnormality of the microcomputer 23, the microcomputer monitoring unit 24 holds and outputs the first signal (low level) immediately before the reset period.

  Next, another example of operation when a power supply voltage drop occurs will be described with reference to FIG. FIG. 4 shows a case where the microcomputer monitoring unit 24 makes a normal determination before resetting and continues resetting as another example of operation when the power supply voltage drops while the starter switch is on. The process is the same as in FIG. 2 until the reset period is reached due to the power supply voltage drop.

  As shown in FIG. 4, when the power supply voltage decreases, the voltage monitoring unit 25 outputs a reset signal (low level) as the second signal. Thereby, the microcomputer 23 is reset, and the output of the control signal and the test signal is stopped. Further, the microcomputer monitoring unit 24 holds and outputs the first signal (high level) immediately before the reset signal is output as the first signal. Further, the latch circuit 26 holds and outputs the control signal (high level) immediately before the reset signal is output as the third signal.

  The reset timer 27 starts counting with the input of a reset signal as a trigger. In the example shown in FIG. 4, since the reset is continued, the count value reaches the predetermined value Nth before the reset is released. When the count value reaches a predetermined value Nth, the reset timer 27 switches the fourth signal from a high level signal for turning on the starter relay 12 to a low level signal for turning off the starter relay 12. When the reset timer 27 outputs a low level signal as the fourth signal, the output of the AND gate 28 becomes a low level signal for turning off the switch 21.

  Thus, by providing the reset timer 27, even when the reset continues, the drive of the starter motor 13 can be stopped after a lapse of a predetermined time from the start of the reset.

  Next, effects of the electronic control device 10 according to the present embodiment will be described.

  In the present embodiment, the first signal that is the output of the microcomputer monitoring unit 24 is input to the AND gate 28. If the microcomputer monitoring unit 24 determines that an abnormality has occurred in the microcomputer 23, the microcomputer monitoring unit 24 outputs a signal (low level signal) indicating the abnormality of the microcomputer 23 as the first signal. For this reason, as shown in FIG. 3, when the microcomputer 23 is abnormal, the output of the AND gate 28 becomes a low level and the switch 21 is turned off. Then, when the switch 21 is turned off, the starter relay 12 can be turned off, and the drive of the starter motor 13 can be stopped. Therefore, it is possible to meet the first need to stop the starter motor 13 when the microcomputer 23 is abnormal.

  In addition, the microcomputer monitoring unit 24 holds the first signal immediately before the reset signal is output and outputs it to the AND gate 28 during the reset period. As shown in FIGS. 2 and 4, when the first signal immediately before the reset signal is output is a high level signal indicating that the microcomputer is normal, the high level signal is held and output. As described above, even if the power supply voltage is reduced and the reset signal is output during cranking with the starter switch 11 turned on, the first signal does not necessarily indicate a malfunction of the microcomputer 23. In particular, when the microcomputer 23 is determined to be normal immediately before resetting, a signal indicating that the microcomputer 23 is normal is output as the first signal even during the reset period. Therefore, even if a reset signal is output during cranking, it is possible to suppress the starter relay 12 from being turned off. That is, the second need for not stopping the starter motor 13 even when the reset signal is output can be met.

  As described above, according to the electronic control apparatus 10 according to the present embodiment, both the first needs and the second needs can be satisfied. If the first signal immediately before the reset signal is output is a low level signal indicating that the microcomputer is abnormal, the microcomputer monitoring unit 24 holds and outputs the low level signal. Therefore, when the microcomputer monitoring unit 24 detects an abnormality of the microcomputer 23, the drive of the starter motor 13 is stopped (prohibited) even during the reset period. Thereby, safety can be ensured.

  In addition, the electronic control device 10 includes a reset timer 27. The reset timer 27 starts counting with the input of a reset signal as a trigger, and continues counting during the reset period. When the count value reaches the predetermined value Nth, the fourth signal is switched from a high level signal for turning on the starter relay 12 to a low level signal for turning off the starter relay 12. Therefore, even when the reset continues, the drive of the starter motor 13 can be stopped when a predetermined time has elapsed since the reset start. Thereby, it is possible to suppress the starter motor 13 from being excessively driven beyond the time required for cranking.

  By the way, immediately after reset release, the microcomputer 23 performs initialization and the like. For this reason, immediately after the reset is released, there is a possibility that the timing of outputting the test signal is delayed as compared with other periods. Therefore, if the specified time is the same as other timings in the reset release period, the test signal may not be detected within the specified time. When the microcomputer monitoring unit 24 always outputs a signal (low level) indicating that the microcomputer 23 is abnormal during the reset period, even if the test signal is not input within the specified time immediately after the reset is released, There is no problem because the level of the output first signal does not change.

  However, when the first signal immediately before the reset is a high level signal indicating that the microcomputer is normal, in the present embodiment, the microcomputer monitoring unit 24 holds the high level signal even during the reset period. Therefore, if the test signal is not input within the specified time immediately after the reset is released, the level of the first signal temporarily falls from the high level to the low level. In this case, it is conceivable that startability is deteriorated, cranking time is prolonged, and vibration is caused by a change in the rotational speed.

  Therefore, in the present embodiment, as shown in FIG. 2, the microcomputer monitoring unit 24 sets a time longer than the specified time t1 in other periods as the specified time t2 immediately after the output of the reset signal is stopped. . According to this, the microcomputer monitoring unit 24 can be configured to hold the first signal immediately before the reset during the reset period, but can prevent the test signal from being input within the specified time immediately after the reset is released. . That is, it is possible to suppress the first signal from dropping immediately after the reset is released. Accordingly, it is possible to suppress the deterioration of the startability, the extension of the cranking time, and the vibration due to the change in the rotational speed.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The example which employ | adopts IC comprised by the hard logic as the microcomputer monitoring part 24 was shown. However, a monitoring microcomputer can be employed as the microcomputer monitoring unit 24.

  The example provided with the power supply 22 as the electronic control apparatus 10 was shown. However, the present invention can also be applied to a configuration in which a power supply voltage is supplied to the microcomputer 23 from a power supply external to the electronic control device 10 without the power supply 22.

  Although the example provided with the reset timer 27 was shown as the electronic control apparatus 10, the reset timer 27 does not need to be provided. However, it is preferable to provide the reset timer 27 because the starter motor 13 can be prevented from being driven beyond the time required for cranking as described above.

  Although an example in which the reset timer 27 counts up has been shown, a timer that counts down can be used.

  Although the microcomputer monitoring part 24 showed the example which sets the time longer than the regulation time t1 of other periods as regulation time t2 immediately after reset cancellation, the reset regulation time is the same immediately after reset cancellation and other than that It is good. However, if the specified time t2 immediately after the reset is released is increased, as described above, the first signal is prevented from dropping immediately after the reset is released. As a result, the startability is deteriorated, the cranking time is prolonged, and the rotation speed is increased. Occurrence of vibration due to change can be suppressed.

DESCRIPTION OF SYMBOLS 10 ... Electronic control apparatus, 11 ... Starter switch, 12 ... Starter relay, 13 ... Starter motor, 20 ... Drive circuit, 21 ... Switch, 22 ... Power supply, 23 ... Microcomputer, 24 ... Microcomputer monitoring part, 25 ... Voltage monitoring part, 26 ... Latch circuit, 27 ... Reset timer, 28 ... AND gate

Claims (3)

An electronic control device for controlling a starter motor (13) via a starter relay (12),
A drive circuit (20) for driving the starter relay;
A microcomputer (23) which operates by being supplied with a power supply voltage and outputs a control signal for controlling the drive of the drive circuit;
The microcomputer determines whether or not the microcomputer is operating normally and outputs a first signal according to the determination result. When it is determined that the microcomputer is not operating normally, the first signal is A microcomputer monitoring unit (24) for outputting a signal for turning off the starter relay;
It is determined whether or not the power supply voltage is at a normal level and outputs a second signal according to the determination result. When it is determined that the power supply voltage is not at a normal level, the microcomputer is used as the second signal. A voltage monitoring unit (25) for outputting a reset signal for resetting to the microcomputer and the microcomputer monitoring unit;
A latch circuit (26) for outputting a third signal based on the control signal and holding and outputting the previous control signal until the next control signal is input regardless of the reset signal. When,
A logic circuit (28) for outputting a logical product of the first signal and the third signal to the drive circuit;
With
The microcomputer monitoring unit holds and outputs the first signal immediately before the reset signal is output as the first signal until the output of the reset signal is stopped. . Based on the second signal, the fourth signal is output to the logic circuit. When the reset signal is output, the count starts, and the reset signal is output until the count value reaches a predetermined value. In order to turn off the starter relay as the fourth signal from the time when the count value reaches the predetermined value until the output of the reset signal is stopped. A timer unit (27) for outputting a signal of
The electronic control device according to claim 1, wherein the logic circuit outputs a logical product of the first signal, the third signal, and the fourth signal to the drive circuit. The microcomputer periodically outputs a test signal for monitoring the validity of the operation of the microcomputer to the microcomputer monitoring unit,
The microcomputer monitoring unit
Set a specified time for monitoring the test signal, and determine whether the microcomputer is operating normally by determining whether the test signal is input within the specified time,
3. The electronic control device according to claim 1, wherein a time longer than the specified time in the other period is set as the specified time immediately after the output of the reset signal is stopped.

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