JP2008144594A - Vehicle speed limiting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle speed limiting device enabling the security of degree of freedom in driving and the maintenance of high drivability by a driver, while restraining an overshoot of a vehicle speed. <P>SOLUTION: When an actual vehicle speed SPD exceeds a limited vehicle speed LtO, speed control by driving operation of the driver is limited, and its maximum speed is limited up to the limited vehicle speed LtO or its vicinity. Such a vehicle speed limiting device comprises a program for detecting the timing t1 being time when a vehicle speed reaches a predetermined high speed, a program for starting (performing) acceleration reduction control based on its timing t1, a program for detecting the timing t2 when acceleration being a control object is reduced up to a predetermined level when performing its acceleration reduction control, and a program for stopping the acceleration reduction control based on its timing t2, by comparing a threshold value (a control threshold value Lt1) set on the lower speed side than the limited vehicle speed LtO with the actual vehicle speed SPD. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a device for limiting the traveling speed of a vehicle, and more specifically, limiting the speed control by a driver's driving operation to limit the maximum speed of the vehicle to a predetermined upper limit speed or the vicinity thereof. Relates to the device.

  In large automobiles, etc., it is already mandatory to install a device that automatically limits the maximum speed of a running vehicle so as not to exceed a predetermined upper speed limit (vehicle speed upper limit), a so-called vehicle speed limiter (speed limiter). Yes. In such a device, when the vehicle speed reaches a preset vehicle speed upper limit, the engine output torque or the like is appropriately controlled even if the driver performs a driving operation that further accelerates the vehicle speed. The traveling speed is controlled within the range up to the set vehicle speed upper limit. For this reason, in such a device, if the maximum speed (statutory maximum speed) that complies with the law is set with respect to the vehicle speed upper limit, operation within the legal maximum speed becomes possible. Further, in recent years, as such a vehicle speed limiting device, a device in which the vehicle speed upper limit can be freely set by a driver, or a road (highway or Devices that automatically set the legal maximum speed according to general roads are being developed. Next, a specific example of such a vehicle speed limiting device will be given and its schematic configuration and operation will be described.

  Conventionally, for example, a device described in Patent Document 1 is known as this type of vehicle speed limiting device. This device allows speed control by the driver's driving operation before the vehicle speed reaches the vehicle speed upper limit so that the vehicle traveling speed (vehicle speed) does not exceed the upper speed limit (vehicle speed upper limit) (overshoot). This is a limitation.

  FIG. 13 shows an operation mode of this apparatus as a time chart. FIG. 13 is a time chart showing the transition of the vehicle speed when the above-described speed restriction is made by the apparatus.

As shown in FIG. 13, in this apparatus, before the vehicle speed reaches the limit vehicle speed Lt10 (vehicle speed upper limit), a deviation D between the limit vehicle speed Lt10 and the vehicle speed SPD10 (actual vehicle speed) at that time is obtained. Based on this, the speed control by the driver's operation is limited. As a result, the maximum speed of the vehicle is limited to the limit vehicle speed Lt10. The vehicle speed restriction is performed in a range (a vehicle speed range) from a predetermined vehicle speed lower than the restriction vehicle speed Lt10 to the restriction vehicle speed Lt10.
US Pat. No. 5,665,026

  As described above, in the apparatus described in Patent Document 1, the above-described excessive increase (overshoot) of the vehicle speed is accurately suppressed and more reliably prevented. However, in this apparatus, speed control by the operation of the driver is limited over a wide range near the vehicle speed upper limit. For this reason, there is a concern that such a vehicle speed limitation is performed over a long period of time, which may give the driver a sense of incongruity due to a mismatch between the vehicle operation of the driver and the actual vehicle speed (actual vehicle speed). Become.

  As described above, although the device described in Patent Document 1 has a particular reliability in terms of preventing the above-described overshoot, the degree of freedom of driving by the driver and high drivability are provided. Sufficient consideration has not been given to the maintenance of the system, and there is still room for improvement.

  The present invention has been made in view of such circumstances, and it is also possible to secure a high degree of driving freedom and maintain high drivability while suppressing an excessive increase (overshoot) in vehicle speed. The main object of the present invention is to provide a vehicle speed limiting device that enables the above.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

  In the first aspect of the present invention, a vehicle configured to have an operation unit (for example, an accelerator pedal or a switch equivalent thereto) operated by a driver is selected according to the operation amount of the operation unit. The present invention is applied to a vehicle speed control device having a driver vehicle speed control means for controlling the traveling speed of the vehicle, and restricts the vehicle speed control by the driver vehicle speed control means of the device so that the maximum speed of the vehicle is a predetermined upper limit speed. Or a vehicle speed limiting device for limiting to the vicinity thereof, vehicle speed acquisition means for sequentially acquiring occasional travel speed of the vehicle, and occasional vehicle speed acquired by the vehicle speed acquisition means, the predetermined vehicle speed upper limit. Vehicle speed upper limit determination means for determining whether or not the vehicle speed exceeds the vehicle speed upper limit determination means, and when the vehicle speed upper limit determination means determines that the vehicle speed exceeds the vehicle speed upper limit, the driver vehicle speed control means Vehicle speed limiting means for limiting the vehicle speed control to limit the maximum speed of the vehicle to the vehicle speed upper limit or the vicinity thereof, and whether the operation unit is operated on the deceleration side or not Acceleration reduction control, which is a control to reduce the acceleration of the vehicle, is started before the vehicle speed obtained by the vehicle speed acquisition means reaches the vehicle speed upper limit, and the acceleration of the vehicle has become sufficiently small. Vehicle acceleration control means for detecting and stopping the acceleration reduction control.

  In this device, basically, after the vehicle speed exceeds the vehicle speed upper limit, the vehicle speed restriction means performs vehicle speed restriction, and before reaching the vehicle speed upper limit, the vehicle acceleration control means performs acceleration reduction control (to limit vehicle speed). Equivalent)) to prevent overshooting of the vehicle speed. That is, the inventor pays attention to the influence of inertia when changing the acceleration of the vehicle, particularly the inertia when accelerating the vehicle, and sufficiently reduces the acceleration of the vehicle before reaching the vehicle speed upper limit (the acceleration reduction control described above). The above-described configuration has been invented by the fact that the rapid acceleration of the vehicle is suppressed and the excessive increase (overshoot) of the vehicle speed is suppressed. Moreover, such acceleration reduction control does not need to be continuously executed until the vehicle speed upper limit is reached. In other words, if the acceleration of the vehicle is sufficiently reduced by this acceleration reduction control, even if the control is stopped appropriately at that time, overshoot is already prevented to a certain extent, so the vehicle speed in normal operation is reduced. This is suppressed for large overshoots. As a result, even before the upper limit of the vehicle speed is reached (particularly in the vicinity of the upper limit of the vehicle speed), after the acceleration reduction control is stopped, a state in which the vehicle speed is not appropriately limited, that is, a state in which the degree of freedom of driving by the driver is increased is formed. It becomes possible to do. As described above, according to the above-described configuration as the vehicle speed control device, an excessive increase (overshoot) of the vehicle speed is suppressed, and further, a degree of freedom of driving by the driver and high drivability can be maintained. It becomes.

As a configuration that also assumes that the vehicle speed reaches the upper limit of vehicle speed before the vehicle acceleration becomes sufficiently small, for example,
The vehicle acceleration limit (acceleration reduction control) by the vehicle acceleration control means is continued and the acceleration of the vehicle is sufficiently reduced. Then, the acceleration reduction control is stopped, and the vehicle acceleration control is shifted to the vehicle acceleration control means. Constitution.
A configuration in which the vehicle speed limit (acceleration reduction control) by the vehicle acceleration control unit is stopped when the vehicle speed reaches the vehicle speed upper limit, and the vehicle speed limit is shifted by the vehicle acceleration control unit.
Etc. are effective.

  By the way, when speed control is performed from the side where the vehicle speed exceeds the vehicle speed upper limit (high speed side), feedback control to the deceleration side (for example, well-known PID control or the like) is performed using the vehicle speed upper limit as a target value. This makes it possible to perform a suitable vehicle speed limit. The inventor pays attention to this point, and in the configuration according to claim 2, that is, in the apparatus according to claim 1, the vehicle speed limiting means determines that the vehicle speed exceeds the vehicle speed upper limit by the vehicle speed upper limit determination means. The invention invented a configuration in which when it is determined, feedback control to the deceleration side is performed so that the vehicle speed obtained by the vehicle speed acquisition means coincides with the vehicle speed upper limit. By adopting such a configuration, it becomes possible to more suitably and more easily realize the vehicle speed restriction by the vehicle speed restriction means.

  According to a third aspect of the present invention, in the apparatus according to the first or second aspect, the driver vehicle speed control means performs the vehicle speed control by controlling an output torque of an engine mounted on the vehicle. The vehicle acceleration control means performs the acceleration reduction control by controlling an output torque of an engine mounted on the vehicle. In order to maintain high drivability, it is effective to control the vehicle speed (traveling speed) and the vehicle acceleration (acceleration in the traveling direction) through torque control.

  Further, in view of practicality and feasibility in the present situation, the configuration according to any one of claims 1 to 3 is more specific, as in the invention according to claim 4, The apparatus according to any one of claims 1 to 3, wherein the vehicle acceleration control means includes a vehicle speed obtained by the vehicle speed acquisition means and a threshold value set on a lower speed side than the vehicle speed upper limit. The start timing detecting means for detecting the start timing, which is the timing when the vehicle speed reaches a predetermined high speed by comparing the two, and the acceleration reduction control is started based on the start timing detected by the start timing detecting means During execution of the acceleration control start execution means and the acceleration reduction control started by the acceleration control start execution means, the acceleration to be controlled reaches a predetermined acceleration level. End timing detection means for detecting (detecting) an end timing that is a reduced timing (the vehicle acceleration has become sufficiently small), and the acceleration control start execution means based on the end timing detected by the end timing detection means An apparatus configuration constituted by acceleration control stop means for stopping acceleration reduction control by is effective. Such a configuration can be realized using a general microcomputer or the like, and is highly practical.

  Also, in this case, as in the invention according to claim 5, the acceleration control start execution means uses the threshold value used by the start timing detection means as the acceleration reduction control to the vehicle toward the deceleration side. A configuration that performs speed feedback control (for example, well-known PID control) is effective. With such a configuration, the above-described acceleration reduction control can be easily and accurately performed as an extension of the vehicle speed control only by changing the target value of the vehicle speed.

  And in invention of Claim 6, in the vehicle speed limiting device of said Claim 4 or 5, the said driver vehicle speed control means respond | corresponded to the operation amount (for example, depression amount of an accelerator pedal) of the said operation part. A driver request torque calculation unit that calculates a driver request torque; and a driver torque control unit that controls an output torque of an engine mounted on the vehicle with the driver request torque calculated by the driver request torque calculation unit as a target value. A request torque determination unit configured to determine whether the acceleration control start execution means is small enough to execute the acceleration reduction control with respect to the magnitude of the driver request torque; and When starting the acceleration reduction control, the required torque determination unit determines that the driver required torque is sufficiently small. When the, characterized in that it is configured with an acceleration torque control unit for controlling by the driver request torque to the target value output torque of an engine mounted on the vehicle, at least.

  In such a configuration, the driver request torque is calculated as a value corresponding to the operation amount of the operation unit based on the driver's intention. In order to maintain high drivability, it is desirable to perform vehicle speed control based on this driver request torque as much as possible. In this regard, in the above configuration, if the acceleration reduction control can be executed with the driver required torque, the vehicle speed control is executed based on the driver required torque by the acceleration torque control unit. Thereby, high drivability is maintained.

  According to a seventh aspect of the present invention, in the apparatus according to the sixth aspect, the required torque determination unit is a vehicle that is acquired by the threshold value used by the start timing detection unit and the vehicle speed acquisition unit. Based on the speed, a determination is made regarding the magnitude of the driver request torque.

  In the acceleration reduction control, the threshold value used by the start timing detection unit and the current vehicle speed acquired by the vehicle speed acquisition unit are magnitudes of torque that enable execution of the acceleration reduction control. As a result, it becomes an important factor for determining the magnitude of torque suitable for vehicle speed limitation. For this reason, as a configuration for determining the magnitude of the driver request torque, a configuration for performing the determination based on the threshold value and the vehicle speed, as in the above configuration, is beneficial in accurately performing the determination.

  In this case, it is of course possible to adopt a configuration in which the above determination (determination regarding the magnitude of the driver request torque) is made directly based on the threshold value and the vehicle speed without obtaining a torque magnitude suitable for vehicle speed limitation. . However, in order to make the determination more accurately, a means for obtaining a magnitude of torque suitable for vehicle speed restriction based on the threshold value and the vehicle speed is provided, and the magnitude of the torque obtained by this means and the driver required torque is determined. A configuration in which the above determination is made based on the comparison is also useful.

  By the way, in the apparatus according to any one of claims 4 to 7, the threshold value used in the start timing detecting means can be set as a fixed value. However, in order to perform more precise vehicle speed control including the acceleration reduction control, a configuration in which this threshold value is variable is effective. And especially as such a structure, like the invention of Claim 8, the said start timing based on the acceleration from which the acceleration acquisition means which acquires the acceleration of the said vehicle occasional, and the said acceleration acquisition means A configuration including vehicle speed determination threshold setting means for variably setting the threshold used by the detection means is effective.

  The threshold value used by the start timing detection means determines the timing (start timing) for executing the acceleration reduction control, and the occasional acceleration of the vehicle has an appropriate timing for executing the acceleration reduction control. It is an important parameter to decide. Therefore, if the threshold value is variably set based on the vehicle acceleration at times as in the configuration described in claim 8, the threshold value is set to an appropriate value according to the vehicle acceleration at times. Is possible. Further, the vehicle speed at that time is also important as a parameter for determining an appropriate timing for executing the acceleration reduction control. For this reason, when determining such a threshold value (threshold value used by the start timing detection means), it is more preferable to determine the value in consideration of the vehicle speed.

  In this case, as in the ninth aspect of the invention, when the vehicle speed determination threshold value setting means sets the threshold value, the threshold value to be set increases as the momentary acceleration acquired by the acceleration acquisition means increases. It is particularly effective to set the threshold value so that the threshold value interval, which is the distance between the upper limit and the vehicle speed upper limit, becomes larger.

  As described above, as the vehicle acceleration at the time when the vehicle speed upper limit is reached is larger, the vehicle speed is more likely to increase excessively (overshoot). For this reason, in order to suppress such overshoot more accurately, as described above, the threshold interval corresponding to the period during which the acceleration reduction control can be performed is increased as the acceleration of the vehicle increases. A configuration that sufficiently reduces the vehicle speed by the time of arrival is effective.

  On the other hand, as the end timing detection means in the apparatus according to any one of claims 4 to 9, for example, an elapsed time from the start of the acceleration reduction control or an occasional time during execution of the control. Also used is to indirectly obtain (estimate) the actual acceleration based on the vehicle speed, etc., and determine whether the actual acceleration has been reduced to a predetermined acceleration level based on the estimated acceleration. Is possible. However, in order to make such a determination more accurately, the end timing detection means directly determines the actual acceleration from, for example, a detection value of the vehicle speed by a vehicle speed sensor or the like, a detection value of the engine speed by a crank angle sensor or the like. In particular, a configuration is particularly effective in which it is determined (calculated) and whether or not the acceleration of the vehicle has been reduced to a predetermined acceleration level based on the obtained actual acceleration. Further, as in the invention according to claim 10, the end timing detection means in the apparatus according to any one of claims 4 to 9, the acceleration acquisition unit for acquiring the acceleration of the vehicle from time to time, An acceleration determination unit that determines whether or not the acceleration at that time is a value corresponding to the predetermined acceleration level by comparing the acceleration at the time acquired by the acceleration acquisition unit with a predetermined threshold value. The device configuration is also effective. In such a configuration, as the threshold value, for example, an appropriate fixed value, an appropriate value obtained in advance through experiments or the like, or a value according to a situation that has been appropriately learned, etc. are set, and the acceleration of the vehicle is set. It becomes possible to easily and accurately determine whether or not it has become sufficiently small. Also, in this case, for example, when the occasional acceleration is smaller than the threshold, it is particularly effective to determine that the acceleration is a value commensurate with the predetermined acceleration level, that is, that the acceleration of the vehicle has become sufficiently small.

  In this case, as in the invention described in claim 11, it is effective that the threshold used by the end timing detection means is set as a value corresponding to the acceleration of the vehicle “0”. is there. With such a configuration, the aforementioned excessive increase (overshoot) of the vehicle speed can be prevented more reliably.

  Further, the apparatus according to any one of claims 1 to 11 is stopped when the acceleration reduction control is stopped by the vehicle acceleration control means, as in the invention according to claim 12. A configuration comprising a control method switching means for switching the control method from the acceleration reduction control to the predetermined vehicle speed control, that is, after the acceleration reduction control is stopped, the control method is automatically changed from the stopped acceleration reduction control to the predetermined vehicle speed control. It is effective to adopt a configuration that switches automatically.

  For example, to maintain high drivability, the control method is switched after the acceleration reduction control is stopped, and as described above, there is no vehicle speed limit, that is, a state where the degree of freedom of driving by the driver is increased. It is beneficial to do. Specifically, as in the invention described in claim 13, in the apparatus described in claim 12, the vehicle speed control of the predetermined method is performed without the vehicle speed limitation related to the maximum speed. It is effective that the vehicle speed control is performed by the driver vehicle speed control means. After preventing overshoot through the acceleration reduction control, switching the control method to such vehicle speed control to increase the driver's freedom of driving, the driver's vehicle operation and actual vehicle speed (actual vehicle speed) described above The uncomfortable feeling caused by the discrepancy with the above is suppressed, and high drivability is maintained.

  However, it is desirable that the apparatus according to claim 12 is configured to switch to an arbitrary control method according to the application or the like, not limited to switching to such a state where there is no vehicle speed limitation. For example, when the vehicle speed is near the upper limit of the vehicle speed when the acceleration reduction control is stopped, the vehicle speed is controlled to the upper limit of the vehicle speed (the vehicle speed is raised to the upper limit of the vehicle speed), and the vehicle speed is once increased at the upper limit of the vehicle speed. A configuration in which the vehicle speed is controlled by another control method after being stabilized is also effective. In addition, in order to alleviate a sudden change in the control method, a configuration in which the control method is switched sequentially in two steps or three or more steps is also effective.

  In the invention according to claim 14, in the device according to any one of claims 1 to 13, at least the vehicle speed restriction related to the maximum speed is made with respect to the vehicle speed control of the driver vehicle speed control means. When the state is switched to the state without the vehicle speed limit, there is provided a target value gradual change means that gently changes the target value related to the output torque control of the engine mounted on the vehicle. By adopting such a configuration, a sudden torque change (torque shock) at the time of switching the presence / absence of speed limitation is mitigated, and deterioration of drivability (drivability) associated with the torque shock is suppressed.

  Hereinafter, an embodiment in which a vehicle speed limiting device according to the present invention is embodied will be described with reference to the drawings. Note that the apparatus according to the present embodiment is also used to limit the maximum speed of the vehicle, similar to the apparatus described in Patent Document 1 described above. Here, a case will be described in which this device is incorporated in an engine control system that performs engine control for a reciprocating engine (internal combustion engine) as an engine for a four-wheeled vehicle, for example.

  First, a schematic configuration of an engine control system equipped with a vehicle speed limiting device according to the present embodiment will be described with reference to FIG. In the present embodiment, a general diesel engine configuration is employed as the configuration of the engine 10. For this reason, the illustration is simplified here, and the description thereof is not described in detail but only a simple description.

  As shown in FIG. 1, this engine control system is mounted on a vehicle 100 that is a four-wheeled vehicle and controls the engine 10. This engine control system is largely constructed with a diesel engine 10 equipped with a common rail fuel injection device as a control target and various sensors for controlling the engine 10, an ECU (electronic control unit) 20 and the like. Has been.

  The engine 10 to be controlled here is, for example, a multi-cylinder four-stroke engine (internal combustion engine) having four cylinders, and an injector (fuel injection valve) that injects high-pressure fuel into the cylinder. It is provided for each cylinder. The fuel that has been pumped from the fuel tank by the high-pressure pump and accumulated in the common rail is injected and supplied to each cylinder at a required amount as needed by the valve opening operation of the injector. That is, when the engine 10 is in operation, intake air is introduced from the intake pipe into the combustion chamber of each cylinder by the opening operation of the intake valve, and this is mixed with the fuel injected from the injector. The fuel and air are compressed by the piston in the cylinder in the state of an air-fuel mixture, ignited (self-ignited), burned, and discharged to the exhaust pipe as exhaust after combustion by the opening operation of the exhaust valve.

  In such an engine control system, the ECU 20 is the part that mainly controls the engine as an electronic control unit. The ECU 20 includes detection signals from various sensors including the sensors shown in FIG. 1, that is, an accelerator sensor 21 that detects an accelerator pedal operation amount (depression amount) and a vehicle speed sensor 22 that detects a traveling speed of the vehicle 100. Are sequentially input. The ECU 20 grasps the operating state of the engine 10 and the user's request based on the detection signals of the various sensors, and operates various actuators such as the injector in accordance with the operation state. In this aspect, various controls related to the engine 10 are performed.

  More specifically, the ECU 20 includes a known microcomputer (not shown). The microcomputer basically includes a CPU (basic processing device) for performing various calculations, a RAM (Random Access Memory) as a main memory for temporarily storing data and calculation results during the calculation, ROM (read-only storage device) as a program memory, EEPROM (electrically rewritable non-volatile memory) as a data storage memory, backup RAM (RAM powered by a backup power source such as an in-vehicle battery), and Consists of various arithmetic devices such as A / D converters and clock generation circuits, input / output ports for inputting / outputting signals to / from the outside, storage devices, signal processing devices, communication devices, etc. Has been. The ROM stores various programs related to engine control including a program related to the vehicle speed limit control, a control map, and the like, and the data storage memory (for example, EEPROM) includes design data of the engine 10 and the like. Various control data to be stored are stored in advance.

  In the present embodiment, the ECU 20 calculates an engine control amount based on various detection signals that are input as needed, and an engine torque (output torque) generated through combustion in the engine 10 based on the engine control amount. ) To control. That is, the ECU 20 calculates a fuel injection amount (engine control amount) corresponding to the driver's accelerator pedal operation amount, for example, at an injection timing corresponding to the current engine operating state, and fuel injection based on the fuel injection amount Is output to the injector. As a result, the output torque of the engine 10 is controlled to a predetermined target value based on the drive amount (for example, valve opening time) of the injector. Note that, as described above, the diesel engine performs combustion by self-ignition, and the intake throttle valve (throttle valve) provided in the intake passage of the engine 10 is normally maintained at a constant opening (for example, a fully open state). For this reason, as the combustion control in the engine 10, the fuel injection amount is mainly controlled.

  By the way, the vehicle speed limiting device of this embodiment is similar to the device described in Patent Document 1 described above in that it limits the maximum vehicle speed. However, in the apparatus of the present embodiment, basically, the vehicle speed is limited after the vehicle speed exceeds the vehicle speed upper limit (predetermined upper limit speed) by the configuration as shown in FIGS. The maximum speed is limited to a predetermined upper limit speed (vehicle speed upper limit) or the vicinity thereof. Before reaching the vehicle speed upper limit, appropriate acceleration reduction control (corresponding to vehicle speed limitation) is executed to prevent the vehicle speed from excessively rising (overshoot). Hereinafter, the vehicle speed limit control will be described in detail with reference to FIGS. 4 to 10 together with FIGS.

The vehicle speed limit control is basically performed through the following three control modes.
-Vehicle speed control (normal control) for controlling the traveling speed of the vehicle 100 in accordance with the accelerator pedal operation amount (depression amount) by the driver in a state where the vehicle speed is not limited.
Vehicle acceleration control (acceleration reduction control) that reduces the acceleration of the vehicle 100 regardless of whether or not the accelerator pedal (operation unit) is operated to the deceleration side. In this embodiment, the acceleration reduction control is executed as vehicle speed feedback control (feedback control) using a threshold value set as a target value on the deceleration side of the vehicle speed at that time.
Vehicle speed control (vehicle speed upper limit control) that performs feedback control (feedback control) to the deceleration side so that the vehicle speed matches a predetermined vehicle speed upper limit. Note that the vehicle speed upper limit (restricted vehicle speed) used for the target value here is, for example, the maximum speed (legal maximum) that complies with laws and regulations, for example, manually by the driver or automatically through the navigation system (car navigation), A desired speed such as (speed) is set.

  First, an aspect of the control mode switching process will be described with reference mainly to FIGS. Here, FIGS. 2 and 3 are block diagrams showing the parts of the ECU 20 related to the vehicle speed limit control, which are divided into functions. FIG. 4 is a flowchart showing the processing procedure of the process related to the selection (start) of the control mode, FIG. 5 is a flowchart showing the processing procedure of the process related to the end of the control mode, and FIG. It is a figure which shows an aspect. 4 and 5 are basically executed sequentially at predetermined crank angles or at predetermined time intervals by executing a program stored in the ROM by the ECU 20. The values of various parameters used in the processes of FIGS. 4 and 5 are stored in a storage device such as a RAM, EEPROM, or backup RAM mounted on the ECU 20 as needed, and are updated as needed.

  In selecting this control mode, as shown in FIG. 4, first, it is determined whether or not the occasional travel speed (actual vehicle speed SPD) of the vehicle 100 sequentially detected through the vehicle speed sensor 22 is within a predetermined range. to decide. That is, in step S11, it is determined whether or not the actual vehicle speed SPD (current value) at that time is in a range of “control threshold Lt1 <actual vehicle speed SPD ≦ restricted vehicle speed Lt0”. In the present embodiment, a program for sequentially detecting the traveling speed of the vehicle 100 with the vehicle speed sensor 22 corresponds to “vehicle speed acquisition means”.

  Next, in step S12, the previous (immediately) detected value (actual vehicle speed SPD (previous value)) of the vehicle speed (traveling speed) sequentially detected is “actual vehicle speed SPD (previous value) ≦ control threshold Lt1. It is judged whether it is in the range of “”. If it is determined in steps S11 and S12 that the actual vehicle speed SPD and its previous value are within the above ranges, the vehicle speed has reached a predetermined high speed (specified by the control threshold Lt1). In subsequent step S13, "1" is set to a flag F1 (initial value is "0") indicating whether or not the execution of acceleration reduction control is permitted (F1 = 1). When the flag F1 is set to “1”, the acceleration reduction control is executed.

  The limit vehicle speed Lt0 corresponding to the upper limit side threshold of the range related to the determination in step S11 is a vehicle speed upper limit set to a desired value by the user, and corresponds to the target value of the vehicle speed upper limit control. On the other hand, the control threshold value Lt1 corresponding to the lower limit side threshold value of the range related to the determination in step S11 and also corresponding to the upper limit side threshold value of the range related to the determination in step S12 is the limit vehicle speed Lt0 which is the upper limit of the vehicle speed. Is set to a lower speed side and is used as a target value in the acceleration reduction control. Details of the setting mode of the control threshold Lt1 will be described later (FIGS. 7 and 8).

  On the other hand, if it is determined in step S11 that the actual vehicle speed SPD (current value) at that time is not in the range of “control threshold Lt1 <actual vehicle speed SPD ≦ restricted vehicle speed Lt0”, in subsequent step S14 Then, it is determined whether or not the actual vehicle speed SPD is in a range of “restricted vehicle speed Lt0 <actual vehicle speed SPD”. If it is determined in step S14 that the actual vehicle speed SPD is within the above range, then in step S15, a flag F2 (initial value) indicating whether or not the execution of the feedback control (vehicle speed upper limit control) is permitted. Sets “0”) to “1” (F2 = 1). When the flag F2 is set to “1”, the vehicle speed upper limit control is executed. On the other hand, if it is determined in step S14 that the actual vehicle speed SPD is not within the above range, then in step S16, "0" is set for each of the flags F1 and F2 (F1 = 0, F2 = 0). And while these flags F1 and F2 are both set to “0”, the normal control (control without vehicle speed limitation) is executed.

  As described above, in the present embodiment, acceleration reduction control, vehicle speed upper limit control, and normal control are executed in accordance with the values of the flags F1 and F2 set through the series of processes shown in FIG.

  At the end of this control mode, as shown in FIG. 5, the control mode being executed is determined based on the values of the flags F1 and F2 (steps S21 and S24), and those control modes (acceleration reduction control) are determined. Whether or not the control mode ends is determined for each vehicle speed upper limit control). When both the acceleration reduction control and the vehicle speed upper limit control are finished, the normal control is executed in principle.

  That is, when the acceleration reduction control is being executed at the end of the control mode, for example, it is first determined in step S20 that “1” is not set in the flag F2, and then in step S21, the flag F1 is set. It is determined that “1” is set. Then, in the subsequent step S22, it is determined whether or not the actual acceleration Acc that is sequentially calculated based on the actual amount of change in the actual vehicle speed SPD is within the range of “actual acceleration Acc ≦ threshold A”. Become. If it is determined that the actual acceleration Acc is within this range, the flag F1 is set to “0” in the subsequent step S23, and the acceleration reduction control is terminated.

  Here, the actual acceleration Acc is calculated based on the vehicle speed (traveling speed) sequentially detected through the vehicle speed sensor 22. Specifically, it is represented by “[actual vehicle speed SPD (current value) −actual vehicle speed SPD (previous value)] / Δt”, which corresponds to the amount of change in the actual vehicle speed SPD per unit time. In the present embodiment, the threshold A is set to a predetermined fixed value “0”, for example.

  In the present embodiment, the program for ending the acceleration reduction control based on the fact that “0” is set in the flag F1 corresponds to “acceleration control stop means”. The program for obtaining the acceleration of the vehicle 100 (actual acceleration Acc) corresponds to the “acceleration acquisition unit”.

  On the other hand, for example, when the vehicle speed upper limit control is being executed, it is first determined in step S20 that “1” is set in the flag F2, and then in step S24, “0” is set in the flag F1. Thus, even if the acceleration reduction control is being executed, the vehicle speed upper limit control is ended when the vehicle speed upper limit control is started.

  Next, in subsequent step S25, it is determined whether or not the actual vehicle speed SPD at that time is in a range of “actual vehicle speed SPD <restricted vehicle speed Lt0”. If it is determined in step S25 that the actual vehicle speed SPD is within this range, in step S26, the flag F2 is set to “0” and the vehicle speed upper limit control is terminated.

  When the control mode switching mode as described above is illustrated, the relationship among the control modes (normal control CL1, vehicle speed upper limit control CL2, acceleration reduction control CL3) is as shown in FIG. Of the three control modes that are selected, executed, and terminated through the series of processes shown in FIGS. 4 and 5, the control mode being executed is input to the switch unit B3 shown in FIG. The switch unit B3 selects an output (target torque value) corresponding to the control mode being executed. As will be described in detail later, the selected output is then subjected to an appropriate gradual change process through the filter unit B4 (FIG. 2) as the target value gradual change means, and the value after the filtering process is It is set as a target torque (control target value) related to the output torque of the engine 10.

  Next, the setting mode of the control threshold value Lt1 will be described in detail with reference mainly to FIGS. FIG. 7 is a flowchart showing a processing procedure of processing related to the setting of the control threshold value Lt1. The series of processes shown in FIG. 7 are also executed sequentially at predetermined crank angles or at predetermined time intervals by executing a program stored in the ROM by the ECU 20. The values of various parameters used in the processing of FIG. 7 are also stored in a storage device such as a RAM, EEPROM, or backup RAM mounted on the ECU 20 as needed, and updated as needed.

  As shown in FIG. 7, in this series of processes, first, in step S31, the actual acceleration Acc (= [actual vehicle speed SPD (current value) −actual Vehicle speed SPD (previous value)] / Δt ") is calculated. In subsequent step S32, a threshold interval ΔLt that is an interval between the control threshold Lt1 and the limit vehicle speed Lt0 is calculated based on the actual acceleration Acc calculated in the previous step S31. The calculation of the threshold interval ΔLt is performed through the control threshold calculation unit B5 shown in FIG. Specifically, the threshold interval ΔLt is calculated based on a map (relational expression) “ΔLt = f (Acc)” as shown in FIG. That is, as the actual acceleration Acc increases, the threshold interval ΔLt becomes a larger value.

  In the subsequent step S33, a temporary threshold value TmpLt1, which is a temporary value of the control threshold value Lt1, is calculated as “TmpLt1 = Lt0−ΔLt”. In subsequent step S34, the provisional threshold value TmpLt1 calculated in step S33 is compared with the actual vehicle speed SPD at that time to determine whether or not the actual vehicle speed SPD is in a range of “SPD> TmpLt1”. To do. Then, only when it is determined that the actual vehicle speed SPD is within this range, the process proceeds to step S35, and the provisional threshold value TmpLt1 is set as the control threshold value Lt1. As described above, in the present embodiment, the acceleration reduction control is selected and executed when the actual vehicle speed SPD increases and exceeds the control threshold Lt1 (SPD> Lt1) (see FIG. 4). In view of this point, in the present embodiment, the above control is performed only when the above-described acceleration reduction control can be selected by using the provisional threshold TmpLt1 when setting the control threshold Lt1 (updating the value) as described above. After the threshold value Lt1 is updated and the acceleration reduction control is selected, the control threshold value Lt1 is basically not updated. In this embodiment, since this control threshold value Lt1 is used for torque control (details will be described later), the above setting mode is adopted to avoid unnecessary updating of the control threshold value Lt1.

  Next, the processing content of each control mode will be described in detail with reference mainly to FIG. FIG. 9 is a flowchart showing the processing contents of the control modes (acceleration reduction control, vehicle speed upper limit control, normal control).

  As shown in FIG. 9, in this series of processes, the control mode being executed is determined based on the values of the flags F1 and F2 (steps S41 and S44), and those control modes (acceleration reduction control, Any one of vehicle speed upper limit control and normal control) is executed. In the present embodiment, the portion that performs the processing of steps S41 and S44 related to this mode selection corresponds to the switch unit B3 shown in FIG.

  That is, when executing this control mode, for example, if it is determined in step S41 that the flag F1 is set to “1”, it is determined that the control mode being executed is acceleration reduction control, and in subsequent step S42. Then, a limit torque LT for performing a predetermined vehicle speed limit on the driver request torque corresponding to the accelerator pedal operation amount (depression amount) is calculated. The limit torque LT is calculated through the PID controller B1b shown in FIG. Specifically, the limit torque LT is calculated based on the control threshold value Lt1 set through the processing of FIG. 7 and the actual vehicle speed SPD at that time (LT = g1 (Lt1, SPD)). In this example, the limit torque LT is set to a larger value as the control threshold Lt1 is a larger value (a value on the higher speed side) and the actual vehicle speed SPD is increased. More specifically, the limit torque LT corresponds to a target torque when performing vehicle speed feedback control (for example, well-known PID control) using the control threshold Lt1 as a target value.

  In the subsequent step S43, the driver request torque DT, which is sequentially calculated according to the accelerator pedal operation amount (depression amount), is compared with the limit torque LT calculated in the above step S42. Is set to the target torque TT (TT = Min (DT, LT)). That is, by this, if it is possible to execute the acceleration reduction control with the driver request torque DT, that is, if the driver request torque DT is smaller, the vehicle speed control is executed based on the driver request torque DT. Accordingly, high drivability is maintained. On the other hand, if the limit torque LT is smaller, the vehicle speed feedback control using the control threshold Lt1 as a target value is performed. The target torque TT is set through the required torque determination unit B2b shown in FIG.

  In the present embodiment, a program that executes vehicle speed control based on the driver request torque DT when the acceleration reduction control can be executed with the driver request torque DT, including the process of step S43, is “acceleration”. It corresponds to a “torque controller”. A program for sequentially calculating the driver request torque DT from time to time based on the accelerator pedal operation amount (depression amount) corresponds to the “driver request torque calculation unit”.

  Further, as described above, before the target torque TT is set as the actual target torque (control target value) at this time, the filter unit B4 (FIG. 2) appropriately changes the control target value. Processing will be performed. For example, when a steep change occurs, the change amount is divided and a change corresponding to the change amount is generated over a longer time than usual. Specifically, for example, if the vehicle speed is changed from “100” to “50”, it is divided into 10 parts, and the change is gently changed to “95”, “90”,... “55”, “50”. To. Alternatively, “75 (= 100− (50/2))”, “62.5 (= 75− (25/2))”, “56.25 (= 62.5− (12.5 / 2))” ,..., And so on, by changing the distance to the target value each time by a predetermined magnification (in this example, a fixed magnification) (subtracting from the control value), the change is made smooth. In any of these filtering processes, a sudden change in torque (torque shock) is alleviated and deterioration of drivability (drivability) associated with the torque shock is suppressed.

  On the other hand, if it is determined in step S41 that “1” is not set in the flag F1, the process proceeds to step S44. If it is determined in this step S44 that the flag F2 is set to “1”, it is determined that the control mode being executed is the vehicle speed upper limit control, and in the following step S45, the same manner as the above step S42. Thus, the limit torque LT is calculated. However, the limit torque LT calculated here corresponds to the target torque in the case of performing vehicle speed feedback control (for example, well-known PID control) with the limit vehicle speed Lt0 as a target value.

  The calculation of the limiting torque LT here is performed through the PID controller B1a shown in FIG. That is, the limit torque LT is calculated based on the limit vehicle speed Lt0 set through the processing of FIG. 7 and the actual vehicle speed SPD at that time (LT = g2 (Lt0, SPD)). Incidentally, the function g2 used in step S45 and the function g1 used in step S42 may be the same function or different functions. These functions can be set arbitrarily according to the application. However, in this example, the limit torque LT is set to a larger value as the control threshold Lt1 and the limit vehicle speed Lt0 are larger values (higher speed side values) and as the actual vehicle speed SPD is greater. With this configuration, an excessive increase (overshoot) in vehicle speed can be prevented more reliably.

  Even in this control mode, in the subsequent step, that is, in step S43, the setting of the target torque TT and the gradual change process are performed based on the limit torque LT set in step S45. At this time, the target torque TT is set through the required torque determination unit B2a shown in FIG.

  On the other hand, if it is determined in step S44 that “1” is not set in the flag F2, the process proceeds to step S46. In step S46, the driver's requested torque DT calculated according to the accelerator pedal operation amount (depression amount) is set to the target torque TT (TT = Min (DT, LT)). Also in this case, the gradual change process is performed by the filter unit B4 (FIG. 2).

  In the present embodiment, the output torque of the engine 10 (FIG. 1) can be obtained with respect to the target value set through the processing of FIG. 9 as described above by sequentially calculating and setting the fuel injection amount as described above. Will be controlled. In the present embodiment, the program for executing the acceleration reduction control based on the target torque (control target value) set through steps S42 and S43 corresponds to “acceleration control start execution means”. A program for executing the vehicle speed upper limit control based on the target torque (control target value) set through steps S45 and S43 corresponds to “vehicle speed limiting means”. A program for executing the normal control based on the target torque (control target value) set through step S46 corresponds to a “driver vehicle speed control means” and a “driver torque control unit”.

  Next, an example of vehicle speed control performed in the above three control modes will be described with reference to FIG. 10, taking as an example a case where the accelerator pedal is continuously depressed to exceed the limit vehicle speed Lt0. 10, (a) is a time chart showing the transition of the actual vehicle speed SPD in this example, and (b) is a driver requested torque DT and a target torque (control following the target torque TT in this example). It is a time chart which shows transition of target value.

  That is, in this example, while the actual vehicle speed SPD is in the low speed region, that is, before the timing t1, the speed control of the target vehicle 100 is performed through the normal control. That is, by the process of step S46 in FIG. 9, the traveling speed of the vehicle 100 is controlled in accordance with the accelerator pedal operation amount (depression amount) by the driver without a vehicle speed limitation. Then, as shown in FIG. 10, when the actual vehicle speed SPD exceeds the control threshold value Lt1 (SPD> Lt1) at timing t1, the control mode is changed from “normal control” to “acceleration reduction control” through the processing of FIG. ”. It should be noted that the actual vehicle speed SPD is sequentially detected through the vehicle speed sensor 22 and that the control threshold Lt1 is sequentially updated through the series of processes shown in FIG. Just as you did.

  Thus, the acceleration reduction control is executed in the period t1 to t2. That is, in this example, the limit torque LT is smaller than the driver request torque DT, and the vehicle speed feedback control with the control threshold value Lt1 as the target value is performed by the processing of steps S42 and S43 in FIG. Due to this vehicle speed limitation, the acceleration of the vehicle 100 is reduced regardless of whether or not the accelerator pedal (operation unit) is operated to the deceleration side. At this time, the change in the target torque (control target value) is subjected to a gradual change process by the filter unit B4 (FIG. 2), and the target torque gradually changes to the limit torque LT as described above. is there.

  Thereafter, when “actual acceleration Acc = 0” at timing t2, the control mode shifts from “acceleration reduction control” to “normal control” through steps S22 and S23 of FIG. Thus, during the period t2 to t3, the traveling speed of the vehicle 100 is controlled in accordance with the accelerator pedal operation amount (depression amount) by the driver with no vehicle speed limitation. In this case as well, the change in the target torque TT is subjected to a gradual change process by the filter unit B4 (FIG. 2), and the target torque (control target value) gradually changes to the driver request torque DT. Just as you did.

  At time t3, when the actual vehicle speed SPD exceeds the limit vehicle speed Lt0 (Lt0 <SPD), the control mode shifts from “normal control” to “vehicle speed upper limit control” through the processing of FIG. As a result, through the processing of steps S45 and S43 in FIG. 9, feedback control to the deceleration side (for example, well-known PID control or the like) so that the vehicle speed exceeding the limit vehicle speed Lt0 (actual vehicle speed SPD) matches the limit vehicle speed Lt0. ) Will be performed. In this case as well, as described above, the change in the target torque (control target value) is subjected to the gradual change process by the filter unit B4 (FIG. 2), and the target torque gradually changes to the limit torque LT as described above. It is.

  After this timing t3, the vehicle speed (actual vehicle speed) is changed while the control mode is shifted alternately from “vehicle speed upper limit control” to “normal control” and from “normal control” to “vehicle speed upper limit control”. The SPD) is basically stably controlled to the limit vehicle speed Lt0.

  Thus, in the apparatus of the present embodiment, basically, the vehicle speed upper limit control (vehicle speed limit) is performed after the vehicle speed exceeds the limit vehicle speed Lt0 (vehicle speed upper limit), and the maximum speed of the vehicle 100 is set to the limit vehicle speed. It is limited to Lt0 or its vicinity. Before reaching the limit vehicle speed Lt0, the acceleration reduction control (corresponding to the vehicle speed limit) is executed to prevent the vehicle speed from excessively rising (overshoot). As a result, an excessive increase (overshoot) in the vehicle speed is suppressed, and it is possible to secure a degree of freedom of driving by the driver and to maintain high drivability.

  As described above, according to the vehicle speed limiting device according to the present embodiment, many excellent effects as described below can be obtained.

  (1) For a vehicle 100 configured to include an accelerator pedal (operation unit) operated by a driver, the traveling speed of the vehicle 100 is controlled in accordance with the operation amount (depression amount) of the accelerator pedal. The vehicle is applied to a vehicle speed control device (installed in the engine ECU 20) having a program (a program for executing normal control, driver vehicle speed control means), and the normal control by the program (corresponding to a driver's operation) is limited to The maximum speed of 100 is limited to a limit vehicle speed Lt0 (vehicle speed upper limit) that is a predetermined upper limit speed or the vicinity thereof. Such a vehicle speed limiting device (this device is also installed in the engine ECU 20), and a program (vehicle speed acquisition means) for sequentially acquiring the traveling speed (actual vehicle speed SPD) of the vehicle 100, and the vehicle speed at that time A program for determining whether or not the vehicle speed limit Lt0 has been exceeded (vehicle speed upper limit determination means, step S14 in FIG. 4) and normal control when it is determined that the vehicle speed has exceeded the vehicle speed limit Lt0 by the processing in step S14 And a program for limiting the maximum speed of the vehicle 100 to the limited vehicle speed Lt0 or the vicinity thereof (a program for executing vehicle speed upper limit control, vehicle speed limiting means). Further, the actual vehicle speed SPD reaches the limit vehicle speed Lt0 in acceleration reduction control, which is control for reducing the acceleration of the vehicle 100 (acceleration in the traveling direction) regardless of whether or not the accelerator pedal is operated to the deceleration side. A program (vehicle acceleration control means) that starts before and detects that the acceleration of the vehicle 100 has become sufficiently small and stops the acceleration reduction control is provided.

  More specifically, the program (vehicle acceleration control means) related to the acceleration reduction control compares the threshold (control threshold Lt1) set on the lower speed side than the limit vehicle speed Lt0 with the actual vehicle speed SPD at each time. Based on a program (start timing detection means, steps S11 to S13 in FIG. 4) for detecting a start timing (for example, timing t1 in FIG. 10), which is a timing at which the vehicle speed reaches a predetermined high speed, and the start timing A program that starts (executes) acceleration reduction control (a program that executes acceleration reduction control, acceleration control start execution means), and the acceleration to be controlled is reduced to a predetermined acceleration level during execution of the acceleration reduction control. A program for detecting end timing (for example, timing t2 in FIG. 10) that is timing ( Device configuration (more precisely speaking, a program) comprising an end timing detection means, steps S21 to S23 in FIG. 5 and a program (acceleration control stop means) for stopping the acceleration reduction control based on the end timing. Composition).

  As a result, an excessive increase (overshoot) in the vehicle speed is suppressed, and it is possible to secure a degree of freedom of driving by the driver and to maintain high drivability.

  (2) When the program for executing the vehicle speed upper limit control is determined that the vehicle speed has exceeded the limit vehicle speed Lt0 by the process of step S14 in FIG. Feedback control to the deceleration side is performed so that the vehicle speed SPD matches the limit vehicle speed Lt0. By doing so, the above-described vehicle speed upper limit control can be realized more suitably and more easily.

  (3) The program for executing the normal control performs vehicle speed control by controlling the output torque of the engine 10 mounted on the vehicle 100, and the program for executing the acceleration reduction control is mounted on the vehicle 100. The acceleration reduction control is performed by controlling the output torque of the engine 10 that has been performed. Thus, by controlling the vehicle speed (traveling speed) and the vehicle acceleration (acceleration in the traveling direction) through torque control, high drivability is maintained.

  (4) The program for executing the acceleration reduction control is to perform feedback control of the vehicle speed to the deceleration side with the control threshold value Lt1 used in steps S11 and S12 of FIG. 4 as a target value. With such a configuration, the above-described acceleration reduction control can be easily and accurately performed as an extension of the vehicle speed control only by changing the target value of the vehicle speed.

  (5) A program (driver request torque calculation unit) that calculates a driver request torque DT corresponding to an operation amount of an accelerator pedal (operation unit), and the calculated driver request torque DT It is configured to have at least a program (driver torque control unit) that controls the output torque of the engine 10 mounted on the vehicle 100 as a target value. Further, the program for executing the acceleration reduction control is a program for determining whether or not the magnitude of the driver request torque DT is small enough to execute the acceleration reduction control (request torque determination unit, FIG. 9). When the driver request torque DT is determined to be sufficiently small in step S43 when starting the acceleration reduction control, the engine 10 mounted on the vehicle 100 with the driver request torque DT as a target value is determined. And a program for controlling the output torque (acceleration torque control unit). Thereby, high drivability is maintained.

  (6) Based on the control threshold value Lt1 used in steps S11 and S12 of FIG. 4 and the actual vehicle speed SPD acquired by the program (vehicle speed acquisition means), torque suitable for vehicle speed limitation (limit torque LT) ) (Step S42 in FIG. 9), and in step S43 in FIG. 9, a determination is made regarding the magnitude of the driver required torque DT based on the limit torque LT. As a result, the determination regarding the magnitude of the driver request torque DT (determination as to whether or not to use the driver request torque DT as the target torque) is made accurately.

  (7) Program (acceleration acquisition means, step S31 in FIG. 7) for obtaining the acceleration of the vehicle (actual acceleration Acc), and a program (vehicle speed determination threshold setting means for variably setting the control threshold Lt1 based on the acceleration at that time) , Steps S32 to S35) of FIG. By doing so, it becomes possible to set the control threshold Lt1 to an appropriate value according to the acceleration of the vehicle 100 from time to time.

  (8) When the control threshold value Lt1 is set in steps S32 to S35 in FIG. 7, the larger the occasional acceleration acquired in step S31, the greater the interval between the control threshold value Lt1 and the limit vehicle speed Lt0 to be set. The control threshold Lt1 is set so that the threshold interval ΔLt becomes a larger interval (see FIG. 8). Thereby, the excessive increase (overshoot) of vehicle speed comes to be suppressed more appropriately.

  (9) By comparing the program (acceleration acquisition unit, step S22 in FIG. 5) for obtaining the acceleration of the vehicle 100 (actual acceleration Acc) with the predetermined threshold A, the acceleration at that time is determined. A device configuration (program configuration) including a program (acceleration determination unit, step S22 in FIG. 5) for determining whether or not a value corresponding to a predetermined acceleration level (“0” in the present embodiment) is obtained. . By doing so, it becomes possible to easily and accurately determine whether or not the acceleration of the vehicle 100 has become sufficiently small.

  (10) In step S22 of FIG. 5, the actual acceleration Acc is obtained (calculated) directly from the detected value of the vehicle speed by the vehicle speed sensor 22, for example. This makes it possible to make the determination more accurately.

  (11) The threshold A used in step S22 of FIG. 5 is set to a value corresponding to the acceleration “0” of the vehicle 100. As a result, a large excessive increase (overshoot) in the vehicle speed is more reliably prevented.

  (12) A configuration comprising control method switching means for switching a control method from the stopped acceleration reduction control to a predetermined vehicle speed control when the acceleration reduction control is stopped, that is, after the acceleration reduction control is stopped The control method is automatically switched from the acceleration reduction control thus performed to the vehicle speed control of the predetermined method (the normal control in the present embodiment). As described above, after preventing overshoot through the acceleration reduction control, the control method is switched to the normal control to increase the degree of freedom of driving of the driver, so that the driver's vehicle operation and the actual vehicle speed (actual vehicle Discomfort caused by a discrepancy with (speed) is suppressed, and high drivability is maintained.

  (13) A configuration including a program (target value gradual change means, filter unit B4 shown in FIG. 2) that gently changes (gradually changes) a target value related to output torque control of the engine 10 mounted on the vehicle 100. did. As a result, a sudden torque change (torque shock) when switching the presence or absence of speed limitation is mitigated, and deterioration of drivability (drivability) associated with the torque shock is suppressed.

  The above embodiment may be modified as follows.

  In the above embodiment, the control threshold value Lt1 is set in the manner shown in FIG. However, in such a setting method, once the control threshold value Lt1 is set, in principle, the control threshold value Lt1 is not reset until the vehicle speed (actual vehicle speed SPD) falls below the control threshold value Lt1. . That is, as indicated by a two-dot chain line SPD0 in FIG. 10, after the vehicle acceleration is sufficiently reduced, the vehicle 100 is decelerated and accelerated again before the traveling speed of the vehicle 100 falls below the control threshold Lt1. In such a case, there is a possibility that the vehicle speed will be sufficiently accelerated by the time the vehicle speed reaches the limit vehicle speed Lt0, and there is a concern about a large excessive increase (overshoot). Therefore, assuming such a case, it is also effective to set the control threshold value Lt1 in a manner as shown in FIG. 11, for example, instead of the processing in FIG.

  That is, as shown in FIG. 11, in this example, as a step preceding steps S31 and S32 in FIG. 7, a step S30 for determining whether or not the value of the flag F1 is “0” is provided, and the flag F1 When the value of “0” is “0”, that is, when the acceleration reduction control is not executed, the processing of steps S31 and S32 (similar to the processing of FIG. 7) is performed. Further, the provisional threshold value TmpLt1 is not used, and instead of steps S33 to S35, step S33a is provided, and the control threshold value Lt1 is always updated through step S33a when the acceleration reduction control is not executed. I have to. Therefore, according to such a setting method (see FIG. 11), as indicated by a two-dot chain line SPD0 in FIG. 10, the vehicle 100 is decelerated once and then the vehicle 100 is decelerated. Even when the traveling speed is accelerated again before falling below the control threshold value Lt1, the control threshold value Lt1 is sequentially updated in the period t2 to t3. That is, by this, the acceleration reduction control is executed before the vehicle speed reaches the limit vehicle speed Lt0, and the acceleration of the vehicle 100 is sufficiently reduced through this control.

  Further, for example, instead of the control mode switching mode shown in FIG. 6, the configuration in which the control mode is increased by one and the control mode is switched in the mode shown in FIG. 12 is also effective.

  That is, as shown in FIG. 12, in this example, the transition time control is performed as a control mode executed when the vehicle acceleration is sufficiently reduced and the acceleration reduction control is stopped (actual acceleration Acc ≦ threshold A). CL4 is newly provided. Specifically, in this control, the vehicle speed is controlled to the limit vehicle speed Lt0 (vehicle speed upper limit) (the vehicle speed is raised to the limit vehicle speed Lt0), and the control mode is shifted to the vehicle speed upper limit control CL2. By stabilizing the vehicle speed at the limit vehicle speed Lt0 in this way, the above-described speed transition as indicated by a two-dot chain line SPD0 in FIG. 10 is less likely to occur.

  -Not limited to this, other control modes (arbitrarily set as control modes executed when the vehicle acceleration is sufficiently reduced and the acceleration reduction control is stopped (actual acceleration Acc≤threshold A)) (Control mode) may be executed. For example, in the control mode switching mode of FIG. 6, when switching the control mode from the acceleration reduction control CL3 to the normal control CL1, one or more predetermined control modes are sandwiched and divided into two stages or three or more stages. The control method may be sequentially switched while alleviating the sudden change (particularly, the change in the target torque).

  In the above embodiment, the filter unit B4 illustrated in FIG. 2 has been described assuming that the output selected by the switch unit B3 is constantly filtered. However, the present invention is not limited to this, and the filter unit B4 may be configured to perform the filtering process only when the control mode is switched. However, performing such filtering processing itself is not an essential configuration, and the filter unit B4 can be omitted as appropriate according to the application.

  -About the detection method (detection configuration) of the vehicle speed and the vehicle acceleration, instead of the detection value of the vehicle speed by the vehicle speed sensor 22, the detection value of the engine rotation speed (crankshaft rotation speed) by the crank angle sensor or the like is used. It may be.

  -About the detection method (detection configuration) of the vehicle acceleration during the execution of the acceleration reduction control, based on the elapsed time from the start of the acceleration reduction control, the current vehicle speed during the execution of the control, etc. The acceleration may be obtained (estimated) indirectly.

  The threshold value A used in step S22 of FIG. 5 is set to a value corresponding to the acceleration “0” of the vehicle 100. However, the present invention is not limited to this, and an appropriate value obtained by an experiment or the like in advance or a value (variable value) according to a situation that is appropriately learned may be set. In this case as well, as in the process of step S22 in FIG. 5, for example, when the acceleration (actual acceleration Acc) is smaller than the threshold A, the acceleration is a value corresponding to a predetermined acceleration level, that is, the acceleration of the vehicle. It is effective to determine that the value of is sufficiently small.

  When setting the control threshold value Lt1 used in steps S11 and S12 in FIG. 4, not only the actual acceleration Acc but also a configuration in which the vehicle speed (actual vehicle speed SPD) is set together is also effective. It is also possible to set the control threshold Lt1 as a fixed value. Furthermore, the threshold value is not limited to one, and a plurality of fixed threshold values may be provided as the control threshold value Lt1 and used for detecting the start timing of the acceleration reduction control while switching the threshold values.

  By using a predetermined map or mathematical formula, the driver request torque DT can be used directly based on the control threshold Lt1 and the vehicle speed (actual vehicle speed SPD) without calculating the limit torque LT. It can also be configured to determine whether or not. That is, in this case, if the driver request torque DT is usable, the driver request torque DT is set as the target torque TT. If not usable, the driver request torque DT is based on the control threshold Lt1 and the vehicle speed according to a predetermined map or formula. Thus, an appropriate value is set for the target torque TT. As this set value, for example, it is effective to use an optimum value (adapted value) obtained in advance through experiments or the like.

  In the above embodiment, the limit torque LT for limiting the vehicle speed is calculated so as to limit the vehicle speed by torque control. However, instead of this, the vehicle speed may be similarly limited by providing a restriction on the accelerator operation amount. In other words, in this case, the driver cannot step on the accelerator pedal beyond the amount of displacement corresponding to the limit torque LT.

  In the above embodiment, the acceleration reduction control is stopped when the vehicle speed reaches the limit vehicle speed Lt0 as a configuration assuming that the vehicle speed reaches the limit vehicle speed Lt0 before the vehicle acceleration becomes sufficiently small. Shifted to the above vehicle speed upper limit control. However, the present invention is not limited to this, and it may be configured such that the acceleration reduction control is continued and the acceleration of the vehicle 100 is sufficiently reduced, and then the acceleration reduction control is stopped to shift to the vehicle speed upper limit control.

  In the above embodiment, the case where the present invention is applied to a diesel engine is mentioned as an example. However, the present invention is basically applied to a spark ignition engine (including a direct injection gasoline engine) as well. Can do.

  In the embodiment and the modification, it is assumed that various kinds of software (programs) are used. However, similar functions may be realized by hardware such as a dedicated circuit.

1 is a configuration diagram showing an outline of an engine control system to which an apparatus according to an embodiment of a vehicle speed limiting apparatus according to the present invention is applied. The block diagram which showed the part which concerns on the vehicle speed restriction | limiting control especially the vehicle speed restriction | limiting apparatus which concerns on this embodiment in block form according to the function. The block diagram which showed the part which concerns on the vehicle speed restriction | limiting control especially the vehicle speed restriction | limiting apparatus which concerns on this embodiment in block form according to the function. The flowchart which shows the process sequence of the process which concerns on selection (start) of control mode. The flowchart which shows the process sequence of the process which concerns on completion | finish of control mode. The figure which shows the switching aspect of control mode. The flowchart which shows the process sequence of the process which concerns on the setting of a control threshold value. A map used to calculate the threshold interval. The flowchart which shows the processing content of each control mode. (A) And (b) is a time chart which shows the one aspect | mode of the vehicle speed control performed by the said control mode, taking as an example the case where an accelerator pedal is stepped on to such an extent that it exceeds a limit vehicle speed, respectively. The flowchart which shows the modification of the setting aspect of a control threshold value. The figure which shows the modification of the switching mode of a control mode. The time chart which shows the operation | movement aspect about an example of the conventional vehicle speed limiting apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 20 ... ECU (electronic control unit), 21 ... Accelerator sensor, 22 ... Vehicle speed sensor, 100 ... Vehicle, B3 ... Switch part, B4 ... Filter part, B5 ... Control threshold value calculation part, B1a, B1b ... PID controller , B2a, B2b... Required torque determination unit.

Claims (14)

Applicable to a vehicle speed control device including a driver vehicle speed control means for controlling a traveling speed of a vehicle according to an operation amount of the operation unit, targeting a vehicle having an operation unit operated by a driver A vehicle speed limiting device that limits vehicle speed control by the driver vehicle speed control means of the device and limits the maximum speed of the vehicle to a vehicle speed upper limit that is a predetermined upper limit speed or in the vicinity thereof,
Vehicle speed acquisition means for sequentially acquiring the running speed of the vehicle sequentially;
Vehicle speed upper limit determination means for determining whether or not the vehicle speed obtained by the vehicle speed acquisition means exceeds the predetermined vehicle speed upper limit;
Vehicle speed that restricts the vehicle speed control by the driver vehicle speed control means to restrict the maximum speed of the vehicle to the vehicle speed upper limit or in the vicinity thereof when the vehicle speed upper limit judging means determines that the vehicle speed exceeds the vehicle speed upper limit. Limiting means,
Acceleration reduction control, which is control for reducing the acceleration of the vehicle, regardless of whether or not the operation unit is operated on the deceleration side, the occasional vehicle speed acquired by the vehicle speed acquisition means reaches the vehicle speed upper limit. Vehicle acceleration control means that starts before and detects that the acceleration of the vehicle has become sufficiently small and stops the acceleration reduction control;
A vehicle speed limiting device comprising:   When the vehicle speed upper limit determining means determines that the vehicle speed exceeds the vehicle speed upper limit, the vehicle speed limiting means moves to the deceleration side so that the vehicle speed obtained by the vehicle speed acquisition means matches the vehicle speed upper limit. The vehicle speed limiting device according to claim 1, wherein feedback control of the vehicle is performed. The driver vehicle speed control means controls the vehicle speed by controlling an output torque of an engine mounted on the vehicle;
The vehicle speed limiting device according to claim 1 or 2, wherein the vehicle acceleration control means performs the acceleration reduction control by controlling an output torque of an engine mounted on the vehicle. The vehicle acceleration control means is
A start timing, which is a timing at which the vehicle speed reaches a predetermined high speed, is detected by comparing the vehicle speed obtained by the vehicle speed acquisition means with a threshold value set at a lower speed than the upper limit of the vehicle speed. Start timing detection means;
Acceleration control start execution means for starting the acceleration reduction control based on the start timing detected by the start timing detection means;
End timing detection means for detecting an end timing that is a timing at which the acceleration to be controlled is reduced to a predetermined acceleration level during execution of acceleration reduction control started by the acceleration control start execution means;
Acceleration control stop means for stopping acceleration reduction control by the acceleration control start execution means based on the end timing detected by the end timing detection means;
The vehicle speed limiting device according to any one of claims 1 to 3, comprising:   The said acceleration control start execution means performs feedback control of the vehicle speed to the deceleration side which uses the said threshold value used by the said start timing detection means as a target value as the said acceleration reduction control. Vehicle speed limiting device. The driver vehicle speed control means calculates a driver request torque calculation unit that calculates a driver request torque according to the operation amount of the operation unit, and sets the driver request torque calculated by the driver request torque calculation unit as a target value to the vehicle. A driver torque control unit that controls the output torque of the mounted engine,
The acceleration control start execution means starts a request torque determination unit that determines whether the magnitude of the driver request torque is small enough to execute the acceleration reduction control, and the acceleration reduction control When the required torque determination unit determines that the required driver torque is sufficiently small, an acceleration torque control unit that controls the output torque of the engine mounted on the vehicle with the driver required torque as a target value; The vehicle speed limiting device according to claim 4 or 5, comprising at least the device.   The required torque determination unit makes a determination regarding the magnitude of the driver required torque based on the threshold value used by the start timing detection means and the occasional vehicle speed acquired by the vehicle speed acquisition means. The vehicle speed limiting device according to claim 6. Acceleration acquisition means for acquiring the acceleration of the vehicle from time to time;
Vehicle speed determination threshold setting means for variably setting the threshold value used in the start timing detection means based on the acceleration at the time acquired by the acceleration acquisition means;
A vehicle speed limiting device according to any one of claims 4 to 7.   The vehicle speed determination threshold value setting means sets a larger threshold value, which is an interval between the threshold value to be set and the vehicle speed upper limit as the occasional acceleration acquired by the acceleration acquisition means increases. The vehicle speed limiting device according to claim 8, wherein the threshold value is set so that The end timing detection means is
An acceleration acquisition unit for acquiring the acceleration of the vehicle from time to time;
An acceleration determination unit that determines whether or not the acceleration at that time is a value commensurate with the predetermined acceleration level by comparing the acceleration at the time acquired by the acceleration acquisition unit with a predetermined threshold;
The vehicle speed limiting device according to any one of claims 4 to 9, comprising:   The vehicle speed limiting device according to claim 10, wherein the threshold value used by the end timing detection unit is set as a value corresponding to an acceleration “0” of the vehicle.   The control system switching means for switching a control system from the stopped acceleration reduction control to a predetermined system vehicle speed control when the acceleration reduction control is stopped by the vehicle acceleration control means. The vehicle speed limiting device according to the item.   13. The vehicle speed limiting device according to claim 12, wherein the vehicle speed control of the predetermined method is vehicle speed control by the driver vehicle speed control means in a state where there is no vehicle speed limit related to the maximum speed.   At least when the vehicle speed control of the driver vehicle speed control means is switched between the state in which the vehicle speed limit related to the maximum speed is made and the state in which the vehicle speed limit is not set, the output torque control of the engine mounted on the vehicle The vehicle speed limiting device according to any one of claims 1 to 13, further comprising target value gradual change means for smoothening a change in the target value according to the above.

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