JP2008291712A - Engine start control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine start control device capable of suitably preventing a starter motor from being continuously driven when completion of engine start can not be confirmed. <P>SOLUTION: This engine start control device is structured such that drive of the starter motor 9 is started in response to an on-operation of a start switch 2, and a stop time of the starter motor 9 is determined base on an input Ne signal. In the engine start control device, a stop condition of the starter motor 9 is changed to stop it when the input of the Ne signal is abnormal and a passage time from the drive start is set to a specified value, whereby the starter motor 9 is prevented from being continuously driven when the input of the Ne signal is stopped and completion of the engine start can not be confirmed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine start control device that starts driving a starter motor in response to an ON operation of a start switch and determines a stop timing of the starter motor based on an input engine speed signal.

  In recent years, push-type start switches that start an engine by pressing a push button have been widely used as engine start switches. In a start control device that employs such a bush-type start switch, the starter motor is started by turning on the start switch (pressing the push button) and the engine speed signal input from the speed sensor is detected. Based on this, the start completion of the engine is determined and the starter motor is automatically stopped. Therefore, in a vehicle equipped with such a start control device, the engine can be started only by performing a push operation of the start switch once.

In a vehicle equipped with such a start control device, if the CPU of the start control device operates abnormally and cannot output a starter motor stop command, the starter motor will continue to be driven without being stopped. Therefore, conventionally, in Patent Document 1, when the starter motor is driven beyond a predetermined time limit, the starter motor continues to be driven by forcibly stopping the starter motor even if there is no stop command. An engine start control device that avoids the situation has been proposed.
JP 2007-002812 A

  By the way, in such an engine start control device, when a rotation speed signal is not input to the start control device due to a failure of the rotation speed sensor or a disconnection of a signal line that transmits a rotation speed signal output from the sensor, Since the start completion of the engine cannot be confirmed, the starter motor cannot be stopped. In addition, even when extremely large noise is superimposed on the signal, it may not be possible to confirm the completion of starting. Even in such a case, in the conventional start control device, since the starter motor is forcibly stopped when the time limit has elapsed, only the situation where the starter motor continues to be driven can be avoided.

  However, even if there is no abnormality, it may take a long time to start the engine for extremely cold start, etc.If the time limit is set too short, the engine can be started in such a case. There is a risk of disappearing. Therefore, it is necessary to set the time limit to be long to some extent so that the engine can be started even during extremely cold start. However, if the time limit is lengthened, the starter motor will continue to be driven for a long time after the start is completed when the start completion cannot be detected as described above, and the starter motor breaks down due to overload. Such as giving an uncomfortable feeling to the camera.

  The present invention has been made in view of such a situation, and the problem to be solved is to suitably prevent the starter motor from being continuously driven when it is not possible to confirm completion of engine start. It is an object of the present invention to provide a start control device for an engine that can be used.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
According to the first aspect of the present invention, the starter motor is started in response to the start switch being turned on, and the starter motor is controlled to be stopped based on the input engine speed signal. In the apparatus, when the input of the rotational speed signal is abnormal, the starter motor stop condition is changed so that the starter motor is stopped when the elapsed time from the start of driving reaches a specified time. It is a summary.

  According to a second aspect of the present invention, the start of the starter motor is started in response to an ON operation of the start switch, and the start time of the engine is determined based on the input engine speed signal. The gist of the control device is to forcibly stop the starter motor when the elapsed time from the start of the start of the starter motor reaches a specified time on condition that the input of the rotational speed signal is abnormal. .

  In each of the above-described configurations, when the input of the rotational speed signal is abnormal and it is impossible to determine completion of engine start, the starter motor is automatically stopped when a specified time has elapsed from the start of driving. become. Therefore, it is possible to suitably prevent the starter motor from being continuously driven when it is not possible to confirm completion of engine start.

  When a starter motor drive time at the time of starting is always limited as in Patent Document 1, it is assumed that the starting time is long, such as a cold start, and the time limit is relatively long. And the starter motor may be driven for an unnecessarily long time. For this reason, problems such as failure of the starter motor due to overload and an uncomfortable feeling to the driver occur. In that respect, in the above configuration, the starter motor drive at the time of starting is specified in time only in a limited situation where the input of the rotational speed signal is abnormal, so it is necessary to make the specified time too long. It is possible to prevent such problems from occurring.

  According to a third aspect of the present invention, in the engine start control device according to the first or second aspect, the gist is that the specified time is set to a normal value of a time required to complete the start of the engine. . In this configuration, when the rotational speed signal is abnormally input, it is the normal value of the time required to complete the engine start, that is, the starter motor drive time required to complete the start when it is not difficult to start, such as a cold start. As a result, the starter motor is stopped. Thus, even if the specified time is set to the minimum necessary length, the engine can be normally started without any trouble.

  According to a fourth aspect of the present invention, in the engine start control device according to any one of the first to third aspects, the start switch is turned on even when the input of the rotational speed signal is abnormal. If it is continued, even if the elapsed time exceeds the specified time, the gist is to forcibly drive the starter motor until the start switch is turned off.

  As mentioned above, when the starter motor is stopped at the specified time when the rotational speed signal is abnormally input, the starter motor drive time is insufficient in situations where the start time is long, such as extremely cold start. It may become impossible to start the engine. On the other hand, in the above configuration, even when the rotational speed signal input is abnormal, if the start switch is kept on, the starter motor can be driven beyond the specified time, so even in a situation where it is difficult to start. The engine can be started.

  According to a fifth aspect of the present invention, in the engine start control device according to the fourth aspect, the specified time is less than the time required for abnormality diagnosis of the rotational speed sensor that outputs the rotational speed signal. The gist.

  When the input of the rotational speed signal is abnormal, it is necessary to perform abnormality diagnosis of the rotational speed sensor that outputs the rotational speed signal to identify the abnormal part. However, if the specified time is less than the time required for such an abnormality diagnosis, if the engine cannot be started within the specified time, the necessary diagnosis time cannot be secured and the abnormal location must be specified. Will not be able to. In that respect, in the above configuration, the starter motor is allowed to continue to be driven beyond the specified time by continuing to turn on the start switch. Can be completed.

  A sixth aspect of the present invention is the engine start control device according to any one of the first to fifth aspects, wherein the start switch is configured as a push-type switch. As in the same configuration, the engine start control device according to claims 1 to 5 is particularly suitable for application to a configuration in which the start switch is a push-type switch.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of an engine start control device according to the present invention will be described in detail with reference to FIGS.
In the start control device of the present embodiment, the starter motor starts to be driven in response to an ON operation of the start switch. The stop timing of the starter motor is basically determined based on the input engine speed signal (Ne signal). Specifically, when the engine speed Ne exceeds the start determination value, the starter motor is stopped. Like to stop.

  When determining the stop timing of the starter motor based on the Ne signal in this way, if the Ne signal input to the start control device is interrupted due to a sensor failure or signal line disconnection, the start completion of the engine is confirmed. The starter motor may continue to be driven. Therefore, in the start control device of the present embodiment, when the Ne signal input is interrupted, the starter motor stop condition is changed, and the starter motor is turned on when the elapsed time from the start of start of the starter motor reaches a specified time. By forcibly stopping, the situation where the starter motor continues to be driven in response to the interruption of the Ne signal input is avoided.

  FIG. 1 schematically shows the overall configuration of the engine start control device of the present embodiment. A starting ECU (electronic control unit) 1 shown in the figure includes a central processing unit (CPU) that performs arithmetic processing related to starting control, a read-only memory (ROM) that stores various programs and data for starting control, A random access memory (RAM) for temporarily storing the results of arithmetic processing and the like, and an input / output port for inputting / outputting signals to / from the outside are provided. Such a start ECU 1 is connected to an engine ECU 4 via an in-vehicle network 3. The engine ECU 4 mainly controls the engine after the start, and includes a CPU, a ROM, a RAM, and an input / output port in the same manner as the start ECU 1.

  A start switch 2 is connected to an input port of the start ECU 1. The start switch 2 is configured as a push-type switch and is disposed in the passenger compartment. On the other hand, a drive circuit 8 for the starter motor 9 is connected to the output port of the start ECU 1. The start ECU 1 outputs a start start signal to the drive circuit 8 to turn on a relay (starter relay) for energizing the starter motor 9 and outputs a stop signal to the drive circuit 8 to start the relay. Is turned off to control the drive of the starter motor 9. The starter motor 9 is connected (cranked) to the engine output shaft in response to energization, and the engine output shaft is rotationally driven by the output to start the engine.

  On the other hand, an Ne sensor 5 that detects an engine rotation speed is connected to an input port of the engine ECU 4 via a signal line 6. The engine ECU 4 outputs the signal (Ne signal) from the Ne sensor 5 directly to the input port of the start ECU 1 via the signal line 7. Further, the engine ECU 4 notifies the Ne signal via the in-vehicle network 3 in response to a request from the start ECU 1.

Hereinafter, the details of the start control in the present embodiment configured as described above will be described.
FIG. 2 shows an example of a start control mode at the normal time, that is, when the Ne signal is normally input to the start ECU 1. The start ECU outputs a start signal to the drive circuit 8 at time t2 immediately after that when the start switch 2 is turned on at time t1 in FIG. As a result, the starter relay is turned on and energization of the starter motor 9 is started.

  When energization of the starter motor 9 is started in this way, the engine output shaft is rotated by the output, and the Ne sensor 5 outputs a pulsed Ne signal accordingly. The start ECU 1 acquires such a Ne signal from the engine ECU 4 via the signal line 7 or the in-vehicle network 3, and monitors the transition of the engine speed Ne based on the acquired Ne signal. When the start ECU 1 confirms that the engine rotational speed Ne exceeds the start determination value, that is, the start of the engine is completed at time t3, the start ECU 1 outputs a stop signal to the drive circuit 8 to turn off the starter relay. . Thus, at the normal time, the stop timing of the starter motor 9 is determined based on the Ne signal.

  On the other hand, FIG. 3 shows an example of the start control mode when the start is performed in a state where the input of the Ne signal to the start ECU 1 is interrupted due to the failure of the Ne sensor 5 or the disconnection of the signal lines 6 and 7. . As shown in the figure, in this case as well, in response to the start switch 2 being turned on at time t4, the start ECU 1 outputs a start start signal to the drive circuit 8 at time t5 immediately thereafter, and the starter relay is turned on. I try to turn it on.

  However, at this time, the Ne signal is not input to the start ECU 1, and therefore it is impossible to confirm the completion of the engine start based on the Ne signal. Therefore, in such a case, the starter ECU 1 drives and stops the starter motor 9 for a predetermined time. More specifically, the starter ECU 1 measures the drive time of the starter motor 9 based on the value of the drive time measurement counter CNT indicating the elapsed time from the start of driving of the starter motor 9. When the value of the drive time measurement counter CNT reaches the stop determination value, the start ECU 1 outputs a stop signal to the drive circuit 8 to turn off the starter relay. For this reason, in the figure, a stop signal is output at time t6 when the value of the drive time measurement counter CNT reaches the stop determination value, and the starter relay is turned off. The value of the stop judgment value is a normal value of the time required for completion of engine start, that is, a starter motor necessary for completion of start under normal start conditions (when it is not difficult to start such as extremely cold start). The starter motor 9 is set to stop in a drive time of 9 (for example, about 2 seconds).

  As described above, in this embodiment, when the Ne signal input is interrupted, the stop condition of the starter motor 9 is set such that the starter motor 9 is stopped when the elapsed time from the start of driving reaches a specified time. I am trying to change it. That is, in the present embodiment, the starter motor 9 is forcibly stopped when the elapsed time from the start of driving reaches a specified time on condition that the input of the Ne signal is interrupted. Therefore, when the start of the engine cannot be confirmed due to the interruption of the Ne signal input, it is possible to suitably avoid the starter motor 9 being continuously driven.

  By the way, when the starter motor 9 is stopped in a specified time when the Ne signal is interrupted, the starter motor 9 is stopped in a relatively short time (2 seconds). Therefore, the engine cannot be started when the time required for starting becomes long, such as during extremely cold starting. Further, the abnormality diagnosis of the Ne sensor 5 requires the engine to be rotated for a certain period of time (for example, about 5 seconds). However, if the engine cannot be started within the specified time, such abnormality diagnosis cannot be performed. Also, it becomes impossible to identify an abnormal part.

  Therefore, in the present embodiment, when the start switch 2 is pressed for a long time, the starter motor 9 is not stopped even if the specified time has elapsed, and the drive of the starter motor 9 is continued while the start switch 2 is on. Like to do.

  FIG. 4 shows an example of a start control mode when the start switch 2 is pressed for a long time with the Ne signal input to the start ECU 1 being interrupted, that is, when the start switch 2 is kept on for a long time. Yes. As shown in the figure, also in this case, in response to the start switch 2 being turned on at time t7, the start ECU 1 outputs a start start signal at time t8 immediately after that to turn on the starter relay. I am doing so.

  Also in this case, since the input of the Ne signal is interrupted, the start ECU 1 measures an elapsed time from the start of driving the starter motor 9 using the drive time measurement counter CNT. However, in this case, the start ECU 1 does not output a stop signal because the ON operation of the start switch 2 is continued even when the drive time measurement counter CNT reaches the stop determination value at time t9. The starter relay is kept on. In this case, the start ECU 1 outputs a stop signal to the drive circuit 8 at time t10 when the start operation of the start switch 2 is released, thereby turning off the starter relay.

  FIG. 5 shows a flowchart of a “starter motor stop determination routine” executed to determine the stop timing of the starter motor 9 in this embodiment. The process of this routine is repeatedly executed by the start ECU 1 at a predetermined control cycle as a regular interrupt process during the period from the output of the start signal to the output of the stop signal.

  When the processing of this routine is started, the start ECU 1 first increments the value of the drive time measurement counter CNT in step S501. In step S502, the start ECU 1 checks whether the Ne signal input is interrupted.

  If the Ne signal is normally input (S502: NO), the start ECU 1 moves the process to step S503, and confirms whether or not the engine speed Ne is equal to or higher than the start determination value in step S503. . The start ECU 1 outputs a stop signal to the drive circuit 8 in step S506 if the engine rotational speed Ne is equal to or higher than the start determination value (S503: YES), and otherwise (S503: NO). The routine processing ends.

  On the other hand, when the input of the Ne signal is interrupted (S502: YES), the start ECU 1 checks in step S504 whether or not the start switch 2 is continuously turned on. If the start switch 2 continues to be turned on (S504: YES), the start ECU 1 ends the process of this routine as it is. If not (S504: NO), the process proceeds to step S505. To do.

  In step S505, the start ECU 1 checks whether or not the value of the drive time measurement counter CNT is equal to or greater than the stop determination value. If the value of the drive time measurement counter CNT is equal to or greater than the stop determination value (S505: YES), the start ECU 1 outputs a stop signal to the drive circuit 8 in step S506, otherwise (S505: NO). The processing of this routine is terminated as it is.

According to the engine start control device of the present embodiment described above, the following effects can be obtained.
(1) In the present embodiment, the stop time of the starter motor 9 at the time of starting is normally determined based on the Ne signal, while the input time of the Ne signal is interrupted, the elapsed time from the start of driving is a specified time. The stop condition of the starter motor 9 is changed so as to be stopped when it becomes. That is, in the present embodiment, the starter motor 9 is forcibly stopped when the elapsed time from the start of driving reaches a specified time on condition that the input of the Ne signal is interrupted. Therefore, it is possible to suitably prevent the starter motor from being continuously driven when it is not possible to confirm completion of engine start. In the present embodiment, the drive time of the starter motor 9 at the start is limited only in a limited situation where the input of the Ne signal is interrupted. For this reason, it is not necessary to set the specified time too long, so that the starter motor 9 may fail due to overloading due to an increase in the driving time of the starter motor 9 or the driver may feel uncomfortable. You will be able to

  (2) In this embodiment, the time for driving the starter motor 9 when the Ne signal is interrupted is set to the normal value of the time required for completion of engine start, that is, the starter motor 9 required for completion of start under normal start conditions. The driving time is set. Therefore, it is possible to prevent the starter motor 9 from being continuously driven for an unnecessarily long time by setting the specified time to a necessary minimum length.

  (3) In the present embodiment, even if the Ne signal input is interrupted, if the start switch 2 is pressed for a long time and the ON operation is continued, the elapsed time exceeds the specified time. In addition, the starter motor 9 is forcibly driven until the start switch 2 is turned off. Therefore, if the start switch 2 continues to be turned on even when the Ne signal is interrupted, the starter motor 9 can be allowed to drive beyond the specified time, making it difficult to start as in the case of extremely cold start. It is possible to complete the engine start even in the situation.

  (4) In the present embodiment, the drive time of the starter motor 9 when the Ne signal is interrupted is set shorter than the time required for abnormality diagnosis of the Ne sensor 5. If it is not possible to start, it will be impossible to identify the abnormal part. Even in such a case, in this embodiment, since the starter motor 9 is allowed to continue to be driven beyond the specified time by continuing the ON operation of the start switch 2, the necessary diagnosis time is ensured and the abnormal part is specified. Will be able to.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, by continuing the ON operation of the start switch 2, the starter motor 9 is allowed to continue to be driven beyond the specified time even when the Ne signal is interrupted. However, the starter motor 9 is not continued to be driven by continuing the ON operation of the start switch 2 unless there is such a need, such as when the abnormality diagnosis of the Ne sensor 5 can be performed within a specified time. Anyway.

  In the above embodiment, the drive time of the starter motor 9 when the Ne signal is interrupted is set to the minimum necessary length as a normal value (about 2 seconds) of the time required for completion of engine start. Such driving time can be appropriately adjusted as necessary. For example, when the starter motor 9 is not continuously driven by continuing the ON operation of the start switch 2 as described above, the engine can be started even in a situation where it is difficult to start the engine, such as a cold start. It is preferable to set the drive time of the starter motor 9 to be long.

  In the above embodiment, the signal input interruption is regarded as an abnormality in the Ne signal input. However, even when extremely large noise is superimposed on the Ne signal and the engine rotational speed Ne cannot be confirmed, the start completion based on the Ne signal is also completed. Confirmation will not be possible. Therefore, in such a case, it may be determined that the Ne signal is abnormally input, and the drive control of the starter motor 9 may be performed in the same manner as when the input is interrupted in the above embodiment. That is, even when the engine rotational speed Ne cannot be confirmed based on the Ne signal due to noise, the stop condition of the starter motor 9 is changed from “when the engine rotational speed Ne exceeds the start determination value” to “elapsed from the start of driving” Change to “When the time reaches the specified time”. As a result, when the input of the Ne signal is interrupted and when the engine rotation speed Ne cannot be confirmed based on the Ne signal due to noise, it is determined that the input of the Ne signal is abnormal, and the specified time has elapsed from the start of driving. The starter motor 9 may be forcibly stopped when the time elapses.

  In the above embodiment, the case where the start switch 2 is configured as a push-type switch has been described. However, a switch other than the push-type switch may be employed as the start switch 2. In short, regardless of the type of the start switch 2, an engine start control device configured to automatically perform the stop timing of the starter motor 9 at the time of start, not by manual operation, but by the determination of completion of engine start based on the Ne signal. The present invention can be applied.

The block diagram which shows typically the whole structure about one Embodiment of this invention. The timing chart which shows an example of the control aspect at the time of normal of the embodiment. The timing chart which shows an example of the control mode at the time of Ne signal input interruption of the embodiment. The timing chart which shows an example of the control aspect when a start switch is long-pressed at the time of Ne signal input interruption similarly. The flowchart of the starter motor stop determination routine employ | adopted as the same embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Start ECU (start control device), 2 ... Start switch, 3 ... In-vehicle network, 4 ... Engine ECU, 5 ... Ne sensor, 6, 7 ... Signal line, 8 ... Drive circuit, 9 ... Starter motor.

Claims (6)

In the engine start control device for starting the starter motor in response to an on operation of the start switch and determining the stop timing of the starter motor based on the input engine speed signal,
An engine characterized by changing a stop condition of the starter motor so that the starter motor is stopped when an elapsed time from the start of driving reaches a specified time when the input of the rotation speed signal is abnormal. Start control device. In the engine start control device for starting the starter motor in response to an on operation of the start switch and determining the stop timing of the starter motor based on the input engine speed signal,
An engine start control device for forcibly stopping the starter motor when an elapsed time from the start of the start of the starter motor reaches a specified time on condition that an input of the rotation speed signal is abnormal . The engine start control device according to claim 1, wherein the specified time is set to a normal value of a time required for completion of engine start. Even if the input of the rotational speed signal is abnormal, if the start switch continues to be turned on, the start switch is turned off even if the elapsed time exceeds the specified time. The engine start control device according to any one of claims 1 to 3, wherein the starter motor is forcibly driven. The engine start control device according to claim 4, wherein the specified time is less than a time required for abnormality diagnosis of a rotation speed sensor that outputs the rotation speed signal. The engine start control device according to any one of claims 1 to 5, wherein the start switch is configured as a push-type switch.

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