JP6406927B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device equipped with an idle stop function.

  Many vehicles that use an engine as a drive source are equipped with a so-called idle stop function (idling stop function) in order to improve fuel consumption and reduce exhaust gas emissions.

In the latest idle stop function, the engine is stopped not only when the vehicle stops before an intersection, but also during deceleration before the vehicle stops. That is, during running of the vehicle, and brake pedal is depressed, and the vehicle speed is a predetermined speed (e.g., 9km / h) If the condition is satisfied that it is less, the engine is locked stop. Thereby, compared with the case where the engine is automatically stopped after the vehicle is stopped, the engine stop time can be increased, and the fuel consumption can be improved and the exhaust gas emission amount can be further reduced. After the engine is automatically stopped, for example, when the foot is released from the brake pedal, the engine is automatically restarted.

JP 2004-245099 A

  For example, when a road is congested with a vehicle, the preceding vehicle that is the last of the traffic is moving forward at a low speed (for example, 5 km / h), and the own vehicle traveling at a higher speed than the preceding vehicle There is a case of approaching the preceding car. In this case, the driver depresses the brake pedal and brings the vehicle closer to the preceding vehicle while operating the brake. Then, when the inter-vehicle distance between the own vehicle and the preceding vehicle becomes an appropriate distance, and the vehicle speed of the own vehicle decreases to almost the same vehicle speed as the preceding vehicle, the driver, for example, releases the brake pedal and creeps. Etc., and wants to keep the vehicle following the preceding vehicle while maintaining the inter-vehicle distance and the vehicle speed.

  However, before the vehicle speed of the host vehicle decreases to the vehicle speed of the preceding vehicle, the above-described idle stop function operates and the engine is automatically stopped. Therefore, the engine is automatically restarted when the vehicle speed of the host vehicle decreases to substantially the same vehicle speed as the preceding vehicle and the driver releases his foot from the brake pedal. As a result, some drivers feel uncomfortable due to the fact that the automatic stop and restart of the engine occur continuously.

  An object of the present invention is to provide a vehicle control device that can prevent a driver from feeling uncomfortable due to the fact that an automatic stop and restart of an engine occur continuously when the vehicle follows the preceding vehicle. It is.

  In order to achieve the above object, the vehicle control device according to the present invention, at least on the condition that the brake of the own vehicle operates and the vehicle speed of the own vehicle is equal to or lower than a predetermined vehicle speed greater than 0 km / h, An idle stop means for automatically stopping the engine of the own vehicle, a preceding vehicle detecting means for detecting the presence / absence of a preceding vehicle within a predetermined distance ahead of the own vehicle and advancing / stopping of the preceding vehicle, and a preceding vehicle detecting means When a preceding vehicle traveling forward within a predetermined distance is detected, when prohibiting means for prohibiting automatic stop of the engine by the idle stop means and when no preceding vehicle is detected within a predetermined distance by the preceding vehicle detecting means, or And a permission means for permitting the automatic stop of the engine by the idle stop means when a preceding vehicle stopped within a predetermined distance is detected by the preceding vehicle detection means.

  According to this configuration, when the preceding vehicle is moving forward within a predetermined distance ahead of the host vehicle, the brake of the host vehicle is activated and the vehicle speed of the host vehicle is equal to or less than a predetermined vehicle speed greater than 0 km / h. Even if the automatic stop condition including at least the above is satisfied, the automatic stop of the engine is prohibited. This allows the engine to automatically stop when the driver tries to follow the preceding vehicle at a speed lower than the predetermined vehicle speed, which is the vehicle speed threshold used for the automatic stop condition, by operating the brake of the own vehicle. Not. Therefore, it is possible to prevent the driver from feeling uncomfortable due to the fact that the automatic stop and restart of the engine occur continuously.

  On the other hand, when there is no preceding vehicle within a predetermined distance ahead of the host vehicle, or when the preceding vehicle is stopped within a predetermined distance ahead of the host vehicle, automatic engine stop is permitted. In this case, the engine is automatically stopped when the brake of the own vehicle is activated and the automatic stop condition including at least that the vehicle speed of the own vehicle is equal to or lower than the predetermined vehicle speed is satisfied. As a result, the engine is stopped not only during a stop due to a straight crossing waiting before the intersection, but also during deceleration before the stop. Therefore, compared with the case where the engine is automatically stopped after the vehicle is stopped, it is possible to improve the fuel consumption and reduce the exhaust gas emission amount by increasing the engine stop time.

  The vehicle control device further includes a preceding vehicle speed detecting means for detecting the vehicle speed of the preceding vehicle that is moving forward, and the vehicle speed of the preceding vehicle that is moving forward is greater than a predetermined vehicle speed that is a threshold of the vehicle speed used for the automatic stop condition. The automatic stop of the engine is not prohibited, and the automatic stop of the engine may be permitted.

  In other words, the vehicle control device further includes a preceding vehicle speed detecting means for detecting the vehicle speed of the preceding vehicle that is moving forward, and the vehicle speed of the preceding vehicle that is moving forward is used as the automatic stop condition as a condition prohibiting automatic engine stop. It may be added that the vehicle speed is equal to or lower than a predetermined vehicle speed, which is a threshold value of the vehicle speed.

  Thus, for example, when the preceding vehicle is traveling at a speed higher than the predetermined vehicle speed on the side beyond the intersection, and the own vehicle stops before the intersection, the brake of the own vehicle is activated, and the own vehicle When an automatic stop condition including at least that the vehicle speed is equal to or lower than a predetermined vehicle speed is satisfied, the engine is automatically stopped. Therefore, the engine can be automatically stopped more appropriately. As a result, it is possible to further improve fuel consumption and further reduce exhaust gas emissions by automatically stopping the engine.

  ADVANTAGE OF THE INVENTION According to this invention, when making the own vehicle follow a preceding vehicle, it can prevent giving an uncomfortable feeling to a driver | operator by the automatic stop and restart of an engine occurring continuously. When stopping the vehicle without following the preceding vehicle, stop the engine while the vehicle is decelerating to improve fuel efficiency and reduce exhaust gas emissions by increasing the engine stop time. Can do.

1 is a block diagram illustrating a configuration of a main part of a vehicle to which a vehicle control device according to an embodiment of the present invention is applied. It is a flowchart which shows the flow of idle stop prohibition / permission processing. It is a flowchart which shows the flow of an idle stop process. It is a flowchart which shows the modification of an idle stop process. It is a flowchart which shows the other modification of an idle stop process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a configuration of a main part of a vehicle 1 to which a vehicle control device according to an embodiment of the present invention is applied.

  The vehicle 1 is an automobile that uses the engine 2 as a drive source. The vehicle 1 has an idle stop (idling stop) function. The idle stop function is a function for automatically stopping the engine 2 (idle stop) in a situation where the output of the engine 2 is unnecessary.

  The vehicle 1 is provided with a brake actuator 3. When the brake pedal disposed in the passenger compartment is depressed with the driver's foot, the hydraulic pressure corresponding to the depression force is transmitted from the brake master cylinder to the brake actuator 3. The hydraulic pressure is distributed from the brake actuator 3 to the wheel cylinders of the brakes provided on the wheels by the function of the brake actuator 3, and the braking force is applied to the wheels from the brakes by the hydraulic pressure.

  The vehicle 1 includes a plurality of ECUs (electronic control units). Each ECU is configured to include a CPU and a memory, for example, and can perform bidirectional communication using a CAN (Controller Area Network) communication protocol. The plurality of ECUs include an engine ECU 11, an attitude control ECU 12, and an idle stop ECU 13.

  The engine 2 is connected to the engine ECU 11 as a control target. The engine 2 is accompanied by a starter for starting the engine 2, a throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an ignition plug for generating electric discharge in the combustion chamber, and the like. The engine ECU 11 is connected to an accelerator sensor 21 for detecting an operation amount of an accelerator pedal disposed in the vehicle interior. The engine ECU 11 controls the start, stop, and output of the engine 2 based on the detection signal input from the accelerator sensor 21 and various information input from other ECUs.

  The brake actuator 3 is connected to the attitude control ECU 12 as a control target. The attitude control ECU 12 is connected to a vehicle speed sensor 22 for detecting the vehicle speed of the vehicle 1 and a brake sensor 23 for detecting an operation amount of the brake pedal. The attitude control ECU 12 keeps the braking and attitude of the vehicle 1 stable based on the detection signals input from the vehicle speed sensor 22 and the brake sensor 23 and various information input from other ECUs (for example, during turning) In order to prevent skidding), the brake actuator 3 is controlled to control the braking force applied to the wheel from each brake.

  The idle stop ECU 13 is connected to a preceding vehicle detection sensor 24 for detecting the presence or absence of a preceding vehicle within a predetermined distance ahead of the vehicle 1 (own vehicle) and the forward / stop of the preceding vehicle. The idle stop ECU 13 executes an idle stop prohibition / permission process and an idle stop process, which will be described later, using the detection signal input from the preceding vehicle detection sensor 24 and various information input from other ECUs.

  As the preceding vehicle detection sensor 24, for example, a laser radar, a millimeter wave radar, an ultrasonic sensor, a monocular camera, or a stereo camera can be employed. Laser radars, millimeter wave radars, ultrasonic sensors, monocular cameras, and stereo cameras each have their merits and demerits. Which one of them is adopted as the preceding vehicle detection sensor 24 is appropriately selected with reference to the merits and demerits. Good. In the configuration employing the laser radar, the inter-vehicle distance between the own vehicle and the preceding vehicle can be detected with high accuracy, but advance / stop of the preceding vehicle cannot be detected with high accuracy. In the configuration employing the millimeter wave radar, both the inter-vehicle distance between the own vehicle and the preceding vehicle and the forward / stop of the preceding vehicle can be detected with high accuracy, but the cost is high. In the configuration employing the ultrasonic sensor, the cost can be kept low, but it is impossible to detect both the distance between the host vehicle and the preceding vehicle and the advance / stop of the preceding vehicle with high accuracy. In the configuration in which the monocular camera is adopted, it is possible to easily detect the advance / stop of the preceding vehicle from the enlargement / reduction change of the image of the preceding vehicle, but it is difficult to detect the inter-vehicle distance between the own vehicle and the preceding vehicle. In the configuration in which the stereo camera is adopted, both the inter-vehicle distance between the own vehicle and the preceding vehicle and the advance / stop of the preceding vehicle can be detected with high accuracy based on the parallax of a plurality of cameras, but the cost is high.

  FIG. 2 is a flowchart showing the flow of idle stop prohibition / permission processing.

  The idle stop prohibition / permission process is repeatedly executed by the idle stop ECU 13 at a constant cycle (for example, every 50 msec) while the vehicle 1 is traveling forward. Note that when the brake pedal of the vehicle 1 is not depressed, the execution of the idle stop prohibition / permission process may be skipped.

  In the idle stop prohibition / permission process, based on the detection signal of the preceding vehicle detection sensor 24, the presence / absence of a preceding vehicle within a predetermined distance ahead of the vehicle 1 and the forward / stop of the preceding vehicle are detected (detected). (Step S1). The predetermined distance is preferably set according to the vehicle speed of the vehicle 1, for example, and may be set on the basis of a numerical value obtained by multiplying the vehicle speed by 2 seconds generally recommended as an inter-vehicle time.

  Thereafter, it is determined whether or not a preceding vehicle exists within a predetermined distance ahead of the vehicle 1 (step S2).

  When the preceding vehicle exists within the predetermined distance (YES in step S2), it is subsequently determined whether or not the preceding vehicle is moving forward (step S3).

  When the preceding vehicle exists within a predetermined distance and the preceding vehicle is moving forward, that is, when the preceding vehicle is moving forward within a predetermined distance from the vehicle 1 (YES in step S3). Then, the automatic stop of the engine 2 (hereinafter referred to as “traveling idle stop”) by the idle stop function while the vehicle 1 is traveling is prohibited (step S4), and the idle stop prohibiting / permitting process is ended. In this case, for example, the prohibition flag provided in the memory of the idle stop ECU 13 is turned on (for example, “1” is set in the prohibition flag).

  On the other hand, when there is no preceding vehicle within a predetermined distance ahead of the vehicle 1 (NO in step S2), or when the preceding vehicle is stopped within a predetermined distance ahead of the vehicle 1 (NO in step S3). ) The idling stop during traveling is permitted (step S5), and the idling stop prohibiting / permitting process is terminated. In this case, for example, the prohibition flag provided in the memory of the idle stop ECU 13 is turned off. Further, a permission flag may be provided in the memory of the idle stop ECU 13 and the permission flag may be turned on (for example, “1” is set in the permission flag).

  FIG. 3 is a flowchart showing the flow of idle stop processing.

  The idle stop process is repeatedly executed at a constant cycle (for example, every 50 msec) by the idle stop ECU 13 while the vehicle 1 is traveling forward.

  In the idle stop process, first, it is determined whether or not a predetermined automatic stop condition is satisfied (step S11). The automatic stop condition is a condition in which, for example, the brake is activated when the brake pedal is depressed, and the vehicle speed of the vehicle 1 is equal to or less than a predetermined vehicle speed (for example, 9 km / h) greater than 0 km / h.

  Specifically, the attitude control ECU 12 detects (detects) the vehicle speed of the vehicle 1 based on a detection signal of the vehicle speed sensor 22 and transmits information on the vehicle speed to the idle stop ECU 13. The idle stop ECU 13 determines whether or not the vehicle speed of the vehicle 1 is equal to or lower than a predetermined vehicle speed based on the vehicle speed information transmitted from the attitude control ECU 12.

  Further, the attitude control ECU 12 detects (detects) the operation amount of the brake pedal based on the detection signal of the brake sensor 23 and transmits, for example, information on the operation amount of the brake pedal to the idle stop ECU 13. In this case, based on the information transmitted from the attitude control ECU 12, the idle stop ECU 13 determines that the brake pedal is depressed if the brake pedal operation amount is equal to or greater than a predetermined amount, and the brake pedal operation amount is If it is less than the predetermined amount, it is determined that the brake pedal is not depressed.

  The attitude control ECU 12 detects the amount of operation of the brake pedal based on the detection signal of the brake sensor 23, and in a state where the amount of operation is a predetermined amount or more, a stop lamp (brake) When the lamp) is lit, information on whether or not the stop lamp is lit may be transmitted to the idle stop ECU 13. In this case, the idle stop ECU 13 determines that the brake pedal is depressed if the stop lamp is lit based on the information transmitted from the attitude control ECU 12, and if the stop lamp is not lit, It may be determined that the pedal is not depressed.

  If the automatic stop condition is not satisfied (NO in step S11), the engine stop command is not output from the idle stop ECU 13 to the engine ECU 11, and the idle stop process is terminated. Since an engine stop command is not output from the idle stop ECU 13 to the engine ECU 11, the engine 2 is not automatically stopped in this case.

  If the automatic stop condition is satisfied (YES in step S11), it is next determined whether or not idling stop during travel is prohibited (step S12). For example, in the configuration in which the prohibition flag is provided in the memory of the idle stop ECU 13, if the prohibition flag is on, it is determined that the idling stop during traveling is prohibited, and if the prohibition flag is off, the idle idling during traveling is determined. It is determined that the stop is not prohibited.

  When the idling stop during traveling is prohibited (YES in step S12), it is subsequently determined whether or not the vehicle 1 (own vehicle) is stopped (step S13).

  When the vehicle 1 is stopped, the vehicle 1 can be regarded as having a vehicle speed of approximately 0 km / h as well as the vehicle 1 having a vehicle speed of 0 km / h. ) May be included.

  When the idling stop during running is prohibited and the vehicle 1 is running (NO in step S13), an engine stop command is issued from the idle stop ECU 13 to the engine ECU 11 even if the automatic stop condition is satisfied. The idle stop process is terminated without outputting. Since an engine stop command is not output from the idle stop ECU 13 to the engine ECU 11, the engine 2 is not automatically stopped in this case.

  When the idling stop during running is prohibited and the vehicle 1 is stopped (YES in step S13), an engine stop command is output from the idle stop ECU 13 to the engine ECU 11, and the idle stop process is terminated. The In response to the output of the engine stop command from the idle stop ECU 13 to the engine ECU 11, the engine 2 is automatically stopped by the engine ECU 11 (step S14).

  On the other hand, when idling stop during traveling is not prohibited, that is, when idling stop during traveling is permitted (NO in step S12), an engine stop command is output from the idling stop ECU 13 to the engine ECU 11, and the idling stop processing is performed. Is terminated. In response to the output of the engine stop command from the idle stop ECU 13 to the engine ECU 11, the engine 2 is automatically stopped by the engine ECU 11 (step S14).

  After the engine 2 is automatically stopped, the idle stop ECU 13 repeatedly determines whether or not a predetermined restart condition is satisfied. The restart condition is, for example, a condition that the foot is released from the brake pedal.

  When the foot is released from the brake pedal and the restart condition is satisfied, an engine start command is output from the idle stop ECU 13 to the engine ECU 11. In response to the output of this engine start command, the engine 2 is restarted by the engine ECU 11.

  As described above, when the preceding vehicle is moving forward within a predetermined distance from the vehicle 1, the brake of the vehicle 1 is activated and the vehicle speed of the vehicle 1 is less than a predetermined vehicle speed greater than 0 km / h. Even if the automatic stop condition is satisfied, the automatic stop of the engine 2 is prohibited. Thus, when the driver activates the brake of the vehicle 1 and tries to follow the preceding vehicle at a speed lower than a predetermined vehicle speed that is a threshold of the vehicle speed used for the automatic stop condition, the engine 2 automatically Not stopped. Therefore, it is possible to prevent the driver from feeling uncomfortable due to the automatic stop and restart of the engine 2 occurring continuously.

  On the other hand, when there is no preceding vehicle within a predetermined distance in front of the vehicle 1 or when the preceding vehicle is stopped within a predetermined distance in front of the vehicle 1, automatic stop of the engine 2 is permitted. In this case, when the automatic stop condition is satisfied, the engine 2 is automatically stopped. As a result, the engine 2 is stopped not only during stopping due to waiting for a straight crossing before the intersection, but also during deceleration before stopping. Therefore, compared with the case where the engine 2 is automatically stopped after the vehicle is stopped, it is possible to improve the fuel consumption and reduce the exhaust gas emission amount by increasing the stop time of the engine 2.

  As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the above-described embodiment, when the preceding vehicle is moving forward within a predetermined distance from the vehicle 1, the engine 2 is automatically operated even if the idling stop during traveling is prohibited and the automatic stop condition is satisfied. The configuration that does not stop was taken up.

  For example, as shown in FIG. 4, when the preceding vehicle is moving forward within a predetermined distance from the vehicle 1 (YES in step S3), the vehicle speed of the preceding vehicle that is moving forward is not limited to this configuration. It may be determined whether the vehicle speed is higher than a predetermined vehicle speed that is a threshold value of the vehicle speed used for the automatic stop condition (step S21). If the vehicle speed of the preceding vehicle is greater than the predetermined vehicle speed (YES in step S21), idling stop during traveling is permitted without being prohibited (step S5), and the vehicle speed of the preceding vehicle is equal to or lower than the predetermined vehicle speed ( NO in step S21), idling stop during traveling may be prohibited (step S4).

  Thus, for example, when the preceding vehicle is traveling at a speed higher than a predetermined vehicle speed on the side beyond the intersection, and the vehicle 1 stops before the intersection, the brake of the vehicle 1 is activated and the vehicle 1 When the automatic stop condition that the vehicle speed is equal to or lower than the predetermined vehicle speed is satisfied, the engine 2 is automatically stopped. Therefore, the engine 2 can be automatically stopped more appropriately. As a result, it is possible to further improve the fuel consumption and further reduce the exhaust gas emission amount by automatically stopping the engine 2.

  Further, for example, as shown in FIG. 5, when the preceding vehicle is moving forward within a predetermined distance from the vehicle 1 (YES in step S3), for example, based on the vehicle speed change of the preceding vehicle that is moving forward. Then, it may be determined whether or not the preceding vehicle is likely to stop (step S31). If it is determined that there is a possibility that the preceding vehicle is stopped (YES in step S31), the idling stop during traveling is permitted without being prohibited (step S5), and there is no possibility that the preceding vehicle is stopped. If it is determined, in other words, if it can be predicted that the preceding vehicle will continue to move forward (NO in step S31), the idling stop during traveling may be prohibited (step S4).

  When the preceding vehicle stops, there is a high possibility that the vehicle 1 will not travel following the preceding vehicle. Therefore, in that case, it is preferable that the engine 2 is automatically stopped when the automatic stop condition is satisfied while the vehicle 1 is traveling. Thereby, the engine 2 can be automatically stopped more appropriately. As a result, it is possible to further improve the fuel consumption and further reduce the exhaust gas emission amount by automatically stopping the engine 2.

  Although it is determined whether there is a possibility that the preceding vehicle is stopped based on the change in the vehicle speed of the preceding vehicle that is moving forward, for example, in a configuration in which a monocular camera or a stereo camera is adopted as the preceding vehicle detection sensor 24. Based on whether or not the stop lamp of the preceding vehicle is lit, it may be determined whether or not the preceding vehicle is likely to stop. In other words, if the stop lamp of the preceding vehicle is lit, it is determined that there is a possibility that the preceding vehicle will stop. If the stop lamp of the preceding vehicle is not lit, the possibility of stopping the preceding vehicle is determined. It may be determined that there is no.

  Further, the process shown in FIG. 4 and the process shown in FIG. 5 may be combined. That is, when the preceding vehicle is moving forward within a predetermined distance ahead of the vehicle 1 (YES in step S3), the vehicle speed of the preceding vehicle that is moving forward is more than a predetermined vehicle speed that is a threshold of the vehicle speed used for the automatic stop condition. Is also determined (step S21 in FIG. 4), and if the vehicle speed of the preceding vehicle is equal to or lower than the predetermined vehicle speed (NO in step S21), it is determined whether the preceding vehicle is likely to stop (step in FIG. 5). S31) When it is determined that there is no possibility of stopping the preceding vehicle (NO in step S31), the idling stop during traveling may be prohibited (step S4).

  As an example of the automatic stop condition, the condition that the brake of the vehicle 1 is activated and the vehicle speed of the vehicle 1 is equal to or lower than the predetermined vehicle speed is taken up. However, the automatic stop condition is not necessarily limited to the exemplified condition, and is exemplified. Another condition, for example, a condition that the steering angle (rotation angle from the neutral position) of the steering wheel is a predetermined angle or less may be added to the above condition.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

1: Vehicle (own vehicle)
2: Engine 11: Engine ECU (idle stop means)
12: Attitude control ECU (preceding vehicle detection means)
13: Idle stop ECU (idle stop means, prohibition means, permission means)
24: preceding vehicle detection sensor (preceding vehicle detection means)

Claims (1)

Idle stop means for automatically stopping the engine of the host vehicle, at least on the condition that the brake of the host vehicle is activated and the vehicle speed of the host vehicle is not more than a predetermined vehicle speed greater than 0 km / h;
Preceding vehicle detection means for detecting the presence or absence of a preceding vehicle within a predetermined distance ahead of the host vehicle and the advance / stop of the preceding vehicle;
Preceding vehicle speed detection means for detecting the vehicle speed of the preceding vehicle in advance;
Even when the preceding vehicle in advance within said predetermined distance by said preceding vehicle detection means is detected, when the preceding vehicle speed in advance that is detected by the preceding vehicle speed detecting means is equal to the predetermined vehicle speed or less in a prohibiting it means for prohibiting the automatic stop of the engine by the idle stop means,
When the preceding vehicle is not detected within the predetermined distance by the preceding vehicle detecting means, or when a preceding vehicle stopped within the predetermined distance is detected by the preceding vehicle detecting means, the idle stop means And a permitting means for permitting automatic stop of the engine.

Images