Vehicle engine torque suppression device

Abstract

To reduce engine torque under a proper condition while considering an unwanted operation.SOLUTION: An engine torque suppression device of a vehicle includes: obstacle detection means which detects the presence of an obstacle in the travel direction of a vehicle; obstacle height detection means which detects the height of the obstacle; and engine torque suppression means which, under a prescribed condition, reduces torque actually produced by an engine compared to the torque corresponding to accelerator opening when the obstacle detection means detects the presence of the obstacle. The engine torque suppression means varies the conditions for reducing the engine torque according to the height of the obstacle detected by the obstacle height detection means.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an engine torque suppression device for a vehicle.

Background Art

[0002] When an obstacle is detected in the traveling direction of the host vehicle, control is performed to reduce the torque actually output by the engine to be lower than the torque corresponding to the accelerator opening, on the condition that the host vehicle is traveling at a low speed or stopped and the accelerator operation by the driver is abrupt (referred to as "false start suppression control").

[0003] In Patent Document 1, it is limited to the case where an obstacle detectable by an external sensor is in a range away from the host vehicle, and when an obstacle (for example, a road step) at a position close to the host vehicle cannot be detected, the position of the obstacle is memorized, and based on the memorized position of the obstacle and the behavior of the host vehicle, the relative position of the current obstacle with respect to the host vehicle is estimated. When there is a possibility of collision with the obstacle, it is disclosed that the driver is notified or the host vehicle is controlled so as not to approach the obstacle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In false start suppression control, conditions for reducing engine torque, such as vehicle speed and accelerator opening, are generally set uniformly.

[0006] Here, obstacles that should be avoided in a collision include not only the vehicle in front, but also relatively tall obstacles such as walls facing the road and utility poles, as well as relatively low obstacles such as parking lot wheel stops, road curbs, and other obstacles. The situations in which collisions with obstacles actually become a problem vary depending on the type of obstacle.

[0007] For example, collisions with preceding vehicles are a concern when following a preceding vehicle, while collisions with wheel stops are a concern when parking or maneuvering into a garage. When following a preceding vehicle, it is necessary to maintain the acceleration required for following while reducing engine torque while there is still enough distance remaining to avoid a collision with the preceding vehicle. On the other hand, when parking or maneuvering into a garage, not much acceleration is required, but since it is necessary to park quickly to alleviate congestion in parking lots, a certain degree of relaxation of the conditions regarding vehicle speed is permitted.

[0008] Thus, in order to reliably avoid collisions with obstacles while suppressing unnecessary reductions in engine torque, it is desirable to appropriately set the conditions for reducing engine torque according to the type of obstacle and the circumstances under which it is recognized as an obstacle.

[0009] Therefore, the present invention aims to provide a vehicle engine torque suppression device that can reduce engine torque under appropriate conditions while taking unnecessary operation into consideration. [Means for solving the problem]

[0010] To solve the aforementioned problems, an engine torque suppression device for a vehicle according to one embodiment of the present invention comprises: an obstacle detection means for detecting the presence of an obstacle in the direction of travel of the vehicle; an obstacle height detection means for detecting the height of the obstacle; and an engine torque suppression means that, when the presence of the obstacle is detected by the obstacle detection means, reduces the torque actually generated by the engine to a torque corresponding to the accelerator opening under predetermined conditions, wherein the engine torque suppression means The conditions for reducing the engine torque are as follows: when only obstacles higher than a predetermined height are detected, when only obstacles lower than the predetermined height are detected, and when both obstacles higher than the predetermined height and obstacles lower than the predetermined height are detected. To make them different. [Effects of the Invention]

[0011] According to the present invention, it becomes possible to appropriately set the conditions for reducing engine torque according to the type of obstacle and the circumstances under which it is recognized as an obstacle, and to reduce engine torque under appropriate conditions while considering unnecessary operation. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing the configuration of a vehicle engine torque suppression device according to one embodiment of the present invention. [Figure 2] This flowchart shows the overall flow of engine torque suppression control performed by the engine torque suppression device of the vehicle according to the same embodiment. [Figure 3] This is a flowchart showing the contents of the torque reduction condition setting process (S103) in the engine torque suppression control described above. [Figure 4] This is an explanatory diagram that shows an overview of torque reduction conditions A to D according to the type of obstacle. [Figure 5] This graph shows the throttle opening APOthr at which torque reduction is implemented under torque reduction condition C. [Figure 6] This graph shows the distance Dthr of the obstacle where torque reduction is implemented under torque reduction condition C. [Figure 7] This is a schematic diagram illustrating the method for estimating the obstacle distance in Dobs. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings.

[0014] Figure 1 is a schematic diagram showing the configuration of a vehicle engine torque suppression device 1 according to one embodiment of the present invention.

[0015] In this embodiment, the engine torque suppression device 1 is composed of an engine controller 101, a front camera 201, and a rear camera 202.

[0016] In this embodiment, the vehicle uses an internal combustion engine (hereinafter simply referred to as "engine") not shown as a driving source for running. The vehicle may be a hybrid vehicle that uses an engine and an electric motor as driving sources. The engine controller 101 controls the output of the engine, that is, the engine torque. By controlling the engine torque, acceleration and deceleration of the vehicle according to the driver's accelerator operation are realized.

[0017] The control targets of the engine controller 101 include a fuel injector 121. The engine controller 101 reads various sensor output information related to engine control, performs a predetermined calculation based on this information, and outputs the actuator operation amount, which is the result of the calculation, to a predetermined engine control device. For example, the engine controller 101 calculates the fuel supply amount to the engine and outputs the fuel injector operation amount corresponding to the fuel supply amount to the fuel injector 121. The fuel injector 121 operates according to the fuel injector operation amount and supplies an amount of fuel corresponding to the fuel supply amount to the engine.

[0018] The engine controller 101 receives, as sensor output information for the basis of calculations, the operation amount of the accelerator pedal (hereinafter referred to as "accelerator opening") APO detected by the accelerator sensor 111, the rotational speed WSPfa of the right front wheel detected by the first wheel speed sensor 112fa, the rotational speed WSPfb of the left front wheel detected by the second wheel speed sensor 112fb, the rotational speed WSPra of the right rear wheel detected by the third wheel speed sensor 112ra, the rotational speed WSPrb of the left rear wheel detected by the fourth wheel speed sensor 112rb, the acceleration ACC of the vehicle detected by the acceleration sensor 113, the steering angle STR of the vehicle detected by the steering angle sensor 114. Specifically, in addition to inputting the rotation angle of the steering wheel, it inputs the start request signal IGN output by the ignition switch 211. The ignition switch 211 functions as a start switch for the vehicle, generates and outputs a start request signal IGN corresponding to the driver's start operation on the vehicle. The start request signal IGN from the ignition switch 211 is output not only to the engine controller 101 but also to the front camera 201 and the rear camera 202 described later. In addition to the above, the engine controller 101 inputs the intake air amount of the engine detected by an air flow meter (not shown).

[0019] The wheel speeds WSPfa, WSPfb, WSPra, and WSPrb are state parameters that are correlated with the traveling speed of the vehicle, that is, the vehicle speed VSP. The wheel speed, for example, can be calculated by converting the average value of the wheel speeds WSPfa, WSPfb, WSPra, and WSPrb detected by all the wheel speed sensors 112fa to 112rb.

[0020] The front camera 201 is installed as an external sensor for forward monitoring, at a position close to the driver's eye level, for example, near the upper edge of the vehicle's windshield. In this embodiment, the front camera 201 is composed of a monocular camera sensor having a predetermined field of view, and captures the forward field of view that falls within the range of the field of view. In this embodiment, the front camera 201 includes a detection unit 201a composed of an image sensor that captures the forward field of view, and a calculation unit 201b composed of a circuit element that performs a predetermined calculation based on the imaging information acquired by the detection unit 201a, for example, image information or video information. Based on the imaging information from the detection unit 201a, the calculation unit 201b detects the presence of an obstacle in front of the vehicle, as well as the height of the obstacle and the distance from the vehicle to the obstacle.

[0021] In this embodiment, in addition to the front camera 201, a rear camera 202 is provided as an external sensor for rearward monitoring. The rear camera 202 can also be configured as a monocular camera sensor having a predetermined field of view, similar to the front camera 201. In this embodiment, the rear camera 202 comprises a detection unit and a calculation unit, and is installed, for example, on the rear bumper portion of the vehicle body to capture the rearward view that falls within the field of view.

[0022] The output information from the front camera 201 and the rear camera 202, specifically the presence of an obstacle, the height of the detected obstacle, and the distance to the obstacle, are all output to the engine controller 101.

[0023] The engine controller 101 is configured as an electronic control unit and includes, for example, a central processing unit, as well as various memories and input / output interfaces. The engine controller 101 and the front camera 201 and rear camera 202 (specifically, the processing unit 201b) are connected to each other in a way that allows them to communicate with one another. Sensor output information input to one of them, such as wheel speeds WSPfa, WSPfb, WSPra, WSPrb and acceleration ACC input to the engine controller 101, can be shared between them, for example, by bus communication.

[0024] In addition to normal engine control, the engine controller 101 performs control to avoid or suppress collision with or contact with an obstacle when it detects the presence of an obstacle in the direction of travel of the vehicle (which may be referred to as "the vehicle" below to distinguish it from other obstacles). The direction of travel of the vehicle may be forward or backward.

[0025] Specifically, when the presence of an obstacle in the vehicle's direction of travel is detected, and the vehicle is traveling at a low speed or is stopped, and the driver's accelerator operation, specifically the pressing of the accelerator pedal, is deemed to be an error, engine torque suppression control is implemented to suppress the engine torque to a predetermined low torque, regardless of the driver's accelerator operation. In this embodiment, the engine torque suppression control suppresses the engine torque to a level that prevents the vehicle from rolling backward while climbing a slope and from rolling forward while descending a slope.

[0026] In this embodiment, the front camera 201 and the rear camera 202 correspond to "external environment sensors" and embody "obstacle detection means," "obstacle height detection means," "obstacle distance estimation means," and "storage means," while the engine controller 101 embodies "engine torque suppression means." Furthermore, the steering angle sensor 114 embodies "steering angle detection means."

[0027] Figure 2 is a flowchart showing the overall flow of engine torque suppression control according to this embodiment. In this embodiment, engine torque suppression control is performed by the engine controller 101 at predetermined intervals after startup.

[0028] Figure 3 is a flowchart showing the contents of the torque reduction condition setting process in engine torque suppression control. The torque reduction condition setting process is executed by the engine controller 101 as a subroutine of engine torque suppression control.

[0029] S101 reads various sensor output information.

[0030] In S102, based on the output information from the front camera 201 and the rear camera 202, it is determined whether or not an obstacle has been detected in the direction of the vehicle's movement, for example, in front of or behind the vehicle. If an obstacle is detected, the process proceeds to S103; otherwise, the control in this routine is terminated.

[0031] In S103, conditions used to determine whether or not to reduce engine torque (hereinafter referred to as "torque reduction conditions") are set. In this embodiment, the torque reduction conditions are set as different conditions depending on the type of obstacle and the circumstances under which it is recognized as an obstacle.

[0032] In S104, it is determined whether the distance from the vehicle to the obstacle (hereinafter referred to as the "obstacle distance") Dobs is less than or equal to a predetermined distance (sometimes referred to as the "torque reduction obstacle distance") Dthr determined by the torque reduction condition; in other words, whether the vehicle is closer to the obstacle than the predetermined distance Dthr. If the obstacle distance Dobs is less than or equal to the predetermined distance Dthr, the process proceeds to S105. If it is longer than the predetermined distance Dthr, the control in this routine is terminated.

[0033] In S105, it is determined whether the vehicle speed VSP is less than or equal to a predetermined speed (sometimes referred to as the "torque reduction vehicle speed") VSPthr, which is determined by the torque reduction conditions. If the vehicle speed VSP is less than or equal to the predetermined speed VSPthr, the process proceeds to S106. If it is higher than the predetermined speed VSP1, the control in this routine is terminated.

[0034] In S106, it is determined whether the accelerator opening APO is greater than or equal to a predetermined opening (sometimes referred to as the "torque-reducing accelerator opening") APOthr, which is determined by the torque reduction conditions. If the accelerator opening APO is greater than or equal to the predetermined opening APOthr, the process proceeds to S107. If it is less than the predetermined opening APOthr, the control in this routine is terminated.

[0035] In the S107, torque reduction is implemented to decrease engine torque. Specifically, the engine torque is reduced to a level lower than the torque corresponding to the accelerator opening APO. In this embodiment, the torque is reduced to a level that prevents the vehicle from rolling backward when going uphill or downhill.

[0036] In S108, it is determined whether a predetermined time has elapsed after the torque reduction has been performed. If the predetermined time has elapsed, the process proceeds to S109; otherwise, the torque reduction continues until the predetermined time has elapsed, maintaining the reduced engine torque. The predetermined time is, for example, 5 seconds.

[0037] In S109, the torque reduction is released, and the engine torque is restored to a level equivalent to the throttle opening. It is preferable to restore the engine torque gradually.

[0038] Moving to Figure 3, in S201, based on the history of the start request signal IGN and vehicle speed VSP, it is determined whether the vehicle has experienced acceleration after starting by turning on the ignition switch 211; in other words, whether there is a history of the vehicle starting up from the previous start to the present. If there is an experience of acceleration after starting, proceed to S202; otherwise, proceed to S207.

[0039] In S202, it is determined whether the detected obstacles include any obstacles higher than a predetermined height Hthr. If obstacles higher than the predetermined height Hthr are included, the process proceeds to S203; otherwise, the process proceeds to S205. In this embodiment, the predetermined height Hthr can be appropriately set as the height of the position where the external sensor, for example, the front camera 201, is located, or a lower position. For example, it is set to a height such that the vehicle moves out of the field of view of the front camera 201 as it approaches the obstacle. An example of the predetermined height Hthr is the height of the lower part of the vehicle's bumper or the bottom of the bumper.

[0040] In S203, it is determined whether the detected obstacles include any obstacles lower than a predetermined height Hthr. If obstacles lower than the predetermined height Hthr are included, the process proceeds to S206; otherwise, it proceeds to S204.

[0041] In the S204, torque reduction condition A is set as a condition for reducing engine torque when the detected obstacles include only tall obstacles, in other words, when the presence of obstacles taller than a predetermined height Hthr is detected.

[0042] In the S205, torque reduction condition B is set as a condition for reducing the detected engine torque when the detected obstacles include only low obstacles, in other words, when the presence of obstacles lower than a predetermined height Hthr is detected.

[0043] In the S206, a torque reduction condition C is set as a condition for reducing engine torque when the detected obstacles include both high and low obstacles; in other words, when the presence of both obstacles higher than a predetermined height Hthr and obstacles lower than a predetermined height is detected.

[0044] In the S207, torque reduction condition D is set as a condition for reducing engine torque when restarting after turning off the ignition switch 211.

[0045] Figure 4 is an explanatory diagram that provides an overview of torque reduction conditions A to D according to the type of obstacle. The specific numerical values ​​for vehicle speed VSP etc. shown in Figure 4 are merely examples illustrating the relative magnitudes of the values ​​for each torque reduction condition A to D, and are not intended to provide guidelines or limit the numerical values, nor do they guarantee the effectiveness of the control.

[0046] Under torque reduction condition A, the obstacle distance Dthr, vehicle speed VSPthr, and accelerator opening APOthr, which are used as criteria for judgment in steps S104 to S106 of the flowchart shown in Figure 2, are set to Dthr=4[m], VSPthr=10[km / h], and APOthr=70~90[%].

[0047] Under torque reduction condition B, the obstacle distance Dthr, vehicle speed VSPthr, and accelerator opening APOthr, which are used as criteria for judgment in S104 to S106 of the flowchart shown in Figure 2, are set as follows: the obstacle distance Dthr is set to 4 [m], the vehicle speed VSPthr is set to 10 [km / h] when moving forward and 15 or 20 [m / h] when reversing, and the accelerator opening APOthr is set to 40 to 60 [%] when driving and 70 to 90 [%] when stopped.

[0048] Under torque reduction condition C, the obstacle distance Dthr, vehicle speed VSPthr, and accelerator opening APOthr, which are used as criteria for judgment in S104 to S106 of the flowchart shown in Figure 2, are set as follows: for the obstacle distance Dthr, it is set to 1 [m] when moving forward and according to the vehicle speed VSP when moving backward; for the vehicle speed VSPthr, it is set to 10 [km / h] when moving forward and 15 or 20 [km / h] when moving backward, and further set according to the obstacle distance Dobs.

[0049] Figure 5 is a graph showing the accelerator opening APOthr at which torque reduction is implemented under torque reduction condition C.

[0050] Under torque reduction condition C, the torque reduction accelerator opening APOthr is set to the first determination opening APO1 when the obstacle distance Dobs is up to a predetermined first distance Dobs11, and to the second determination opening APO2 when it is from the first distance Dobs11 to a predetermined second distance Dobs12. The second determination opening APO2 is a larger opening than the first determination opening APO1, and in this embodiment, the torque reduction accelerator opening APOthr is allocated proportionally between the first determination opening APO1 and the second determination opening APO2 in the range from the first distance Dobs11 to the second distance Dobs12.

[0051] In this embodiment, as previously mentioned, the first distance Dobs11 is 1 [m] and the second distance Dobs12 is 2 [m]. The first determination opening degree APO1 is an opening degree in the range of 40 to 60 [%], and the second determination opening degree APO2 is an opening degree in the range of 70 to 90 [%].

[0052] Figure 6 is a graph showing the distance Dthr of the obstacle where torque reduction is implemented under torque reduction condition C.

[0053] Under torque reduction condition C, the torque reduction obstacle distance Dthr is set to the second determination distance Dobs22 until the vehicle speed VSP reaches a predetermined first vehicle speed VSP1, and to the first determination distance Dobs21 from the first vehicle speed VSP1 to a predetermined second vehicle speed VSP2. The second determination distance Dobs22 is a longer distance than the first determination distance Dobs21, and in this embodiment, the torque reduction obstacle distance Dthr is allocated proportionally between the second determination distance Dobs22 and the first determination distance Dobs21 in the range from the first vehicle speed VSP1 to the second vehicle speed VSP2.

[0054] In this embodiment, as previously mentioned, the first vehicle speed VSP1 is 10 km / h, and the second vehicle speed VSP2 is 15 or 20 km / h. The first determination distance Dobs21 is 1 m, and the second determination distance Dobs22 is 2 m.

[0055] Under torque reduction condition D, the obstacle distance Dthr, vehicle speed VSPthr, and accelerator opening APOthr, which are used as criteria for judgment in S104 to S106 of the flowchart shown in Figure 2, are set to Dthr=0.5[m], VSPthr=0[km / h], and APOthr=30[%].

[0056] The criteria for each of the torque reduction conditions A through D are explained below.

[0057] (1) Torque reduction condition A Obstacles higher than the specified height Hthr include preceding vehicles and walls facing the road.

[0058] By setting the torque reduction activation speed (VSPthr) to 10 km / h, torque reduction can be implemented until immediately after starting, while avoiding situations where torque reduction is activated after the vehicle speed (VSP) exceeds 10 km / h and the vehicle transitions to normal driving.

[0059] By setting the torque reduction accelerator opening (APOthr) to a range of 70-90%, the frequent occurrence of torque reduction when following a preceding vehicle can be avoided.

[0060] By setting the torque reduction obstacle distance Dthr to 4 [m], the torque reduction is prevented from activating when the distance to an obstacle (e.g., a preceding vehicle) is reduced, thus avoiding situations where following is hindered. At the same time, sufficient distance is ensured after the torque reduction is implemented to prevent an immediate collision with the obstacle.

[0061] (2) Torque reduction condition B Obstacles lower than the specified height Hthr include parking lot wheel stops and road curbs.

[0062] The torque reduction speed VSPthr is set to 10 km / h when moving forward, while it is set to 15 or 20 km / h when reversing, thus adjusting the conditions according to the situation when reversing. Specifically, since it is conceivable that the driver may not notice low obstacles, such as wheel chocks, when reversing, the torque reduction speed VSPthr is increased compared to when moving forward, and the conditions for torque reduction are relaxed. As an example, 20 km / h is given, but since it is rare to reach this speed when reversing, a speed lower than 20 km / h within a higher range than when moving forward, such as 15 km / h, may also be used.

[0063] The torque reduction accelerator opening APOthr is set to a range of 70-90% when the vehicle is stationary, and to a range of 40-60% when the vehicle is in motion. This allows for torque reduction even at relatively small accelerator openings, without excessively affecting driving during parking, thus preventing the vehicle from having enough inertia to overcome low obstacles such as wheel stops or bumps. On the other hand, when stationary, torque reduction is only permitted at relatively large accelerator openings to avoid excessively impairing starting ability. Even if a lower obstacle that is not classified as an obstacle to be avoided is detected, engine torque is still generated until a relatively large accelerator opening is reached, making it possible to overcome the obstacle and continue driving.

[0064] By setting the torque reduction obstacle distance Dthr to 1 [m], for example, the torque reduction will not activate even if the vehicle is far from the wheel chock, thus preventing smooth parking. On the other hand, when approaching an obstacle, the conditions regarding vehicle speed and accelerator opening are relaxed, allowing the torque reduction to be actively implemented to prevent the vehicle from colliding with the obstacle with excessive force.

[0065] (3) Torque reduction condition C As an example of detecting both obstacles lower than a predetermined height Hthr and obstacles higher than that, consider a parking lot where a building or a wall separating the site (a high obstacle) is located behind a wheel stop (a low obstacle).

[0066] By setting the torque reduction speed (VSPthr) to 10 km / h when moving forward and 15 or 20 km / h when reversing, torque reduction can be implemented even at higher speeds if the driver continues to press the accelerator pedal despite the presence of buildings or walls and approaches a wheel stop. This prevents the vehicle from failing to stop at the wheel stop and instead going over it.

[0067] The torque reduction accelerator opening APOthr is set to a range of 70-90% at a distance of 2m from an obstacle (e.g., a wheel stop), while decreasing as the vehicle approaches the obstacle, setting it to a range of 40-60% at a distance of 1m or closer to the obstacle. This assumes that the driver's awareness of buildings and walls is reliable when the vehicle is far from the wheel stop, thus suppressing the implementation of torque reduction and allowing acceleration through engine torque generation. However, if the driver continues to press the accelerator pedal even when approaching the wheel stop, the accelerator opening condition is relaxed, allowing torque reduction to be implemented even at a relatively low accelerator opening, thus preventing the vehicle from gaining further momentum.

[0068] The torque reduction obstacle distance Dthr is set to 1 [m] when moving forward, while when reversing, it is shortened as the vehicle speed VSP increases, set to 2 [m] at 10 [km / h] or lower, and shortened as the vehicle speed VSP increases, set to 1 [m] at 15 or 20 [km / h]. This is based on the premise of performing torque reduction when approaching an obstacle (wheel stop) as in parking situations, but at relatively low vehicle speeds, torque reduction can be performed even when the vehicle is far from the wheel stop. This prevents situations where the vehicle speed increases due to acceleration with an accelerator opening of less than 70% before approaching the obstacle, and even if torque reduction is performed, the vehicle cannot stop at the wheel stop and ends up going over it.

[0069] (4) Torque reduction condition D This assumes that the vehicle is stationary when restarting after turning off the ignition switch 211.

[0070] Set the torque reduction speed VSPthr to 0 [km / h].

[0071] By setting the throttle opening APOthr for torque reduction to 30%, and the obstacle distance Dthr for torque reduction to 0.5m, considering that situations where the vehicle actively closes the distance to an obstacle when starting from a standstill are rare, torque reduction is permitted only when the vehicle is close to an obstacle. Furthermore, the throttle opening condition is relaxed in such cases to avoid situations where engine torque is generated despite being close to an obstacle, potentially leading to a collision.

[0072] Here, when restarting after ignition is turned off, if the vehicle speed VSP is higher than 0 [km / h], it is assumed that there is a history of starting up since the restart and that acceleration experience has already been gained. In this case, proceed from S201 to S202 in the flowchart shown in Figure 3 to set one of the torque reduction conditions A to C.

[0073] The calculation units of the front camera 201 and the rear camera 202 each have a memory that stores the calculation results and can retain them even after the ignition switch 211 is turned off. Then, for low obstacles that move out of the field of view as the vehicle approaches, the detection of the obstacle distance Dobs is performed as follows.

[0074] Figure 7 is a schematic diagram illustrating the method for estimating the obstacle distance Dobs. Obstacles OBS and OBS' are located at different relative distances D1 and D2 from the vehicle V. Here, obstacle OBS, which was at relative distance D2 at time t1, is assumed to have moved to relative distance D1 (obstacle OBS') at time t2 due to the vehicle's forward movement. In Figure 7, the field of view R that can be captured by the front camera 201 is shown by a dashed line, and the angle of view of this field of view is angle A in the vertical direction.

[0075] At time t1, the obstacle OBS is within the field of view A of the front camera 201, but at time t2, it is outside this field of view A. Therefore, the distance D1 of the obstacle OBS' at the present time, i.e., at time t2, cannot be detected using the imaging information acquired by the front camera 201.

[0076] The calculation unit 201b of the forward camera 201 detects the distance D2 of the obstacle OBS at the time it detects the presence of the obstacle OBS, and also detects the distance traveled by the vehicle after detecting the presence of the obstacle OBS. By subtracting this travel distance from the obstacle distance D2, it estimates the current distance D1 of the obstacle OBS'. The vehicle's travel distance can be calculated based on the vehicle speed and the time taken to travel.

[0077] The engine torque suppression device 1 for a vehicle according to this embodiment has the above configuration. The effects obtained by this embodiment will be described below.

[0078] Objects recognized as potential obstacles for vehicle collisions are not all the same or similar in height. Some are relatively high, such as preceding vehicles or walls facing the road, while others are relatively low, such as parking lot wheel stops, road curbs, and other obstacles. Furthermore, different types of obstacles are perceived differently in different situations.

[0079] According to this embodiment, firstly, the presence of an obstacle in the direction of travel of the vehicle is detected, as well as the height of the obstacle. When an obstacle is detected, the conditions for reducing the actual engine torque to a level equivalent to the throttle opening (i.e., torque reduction conditions A to D) are varied according to the height of the obstacle. This makes it possible to reduce the engine torque at an appropriate timing under appropriate conditions according to the type of obstacle and the circumstances under which it is recognized as an obstacle.

[0080] Secondly, by varying the conditions for reducing engine torque depending on whether only tall obstacles are detected, only low obstacles are detected, or both tall and low obstacles are detected, it becomes possible to reduce engine torque at a more appropriate time and under more appropriate conditions depending on the situation in which obstacles are recognized.

[0081] Specifically, as an example of detecting both high and low obstacles, when parking in a situation where there is a building or a wall separating the property behind the wheel stop, even though the driver is likely to be aware of the obstacle due to the wall, it is possible to avoid situations where the engine torque is unnecessarily reduced at a position far from the obstacle, causing delays during parking.

[0082] Thirdly, when only low obstacles are detected, compared to when only high obstacles are detected, the throttle opening required to reduce engine torque is reduced, the vehicle speed is increased, or the distance to the obstacle is shortened. This makes it possible to reduce engine torque at the appropriate time and under appropriate conditions for the situation when low obstacles are recognized.

[0083] Specifically, in cases where a low obstacle, such as a parking lot wheel stop, is present, it is conceivable that the driver may not recognize its presence. By enabling a reduction in engine torque even at smaller accelerator openings or higher vehicle speeds (in other words, by relaxing the conditions regarding accelerator opening and vehicle speed), it becomes possible to more actively avoid acceleration caused by the driver's erroneous accelerator operation. Furthermore, by reducing engine torque as the vehicle approaches the wheel stop, it becomes possible to avoid unnecessarily reducing engine torque even when the vehicle is far from the wheel stop, thus preventing delays in parking.

[0084] Fourthly, when both tall and short obstacles are detected, it becomes possible to reduce engine torque at the appropriate time and under appropriate conditions according to the situation.

[0085] Specifically, as an example of detecting obstacles of both height and depth, in a situation where there is a building or a wall separating the property behind a wheel stop, the presence of the wall makes it highly likely that the driver is aware of the obstacle's existence, and the reliability of the driver's accelerator operation is high. Therefore, while the vehicle is far from the obstacle, the reduction in engine torque is suppressed to ensure acceleration, while as the vehicle approaches the obstacle, the engine torque is reduced even at a higher vehicle speed and with a smaller accelerator opening, thereby preventing a forceful collision with the wheel stop and avoiding the vehicle going over it.

[0086] Furthermore, when reversing, the engine torque is reduced as the vehicle approaches an obstacle, especially at higher speeds. This helps avoid collisions with obstacles (such as wheel chocks) while facilitating quick parking.

[0087] Fifth, when restarting after the ignition is turned off, if an obstacle is not detected or is located relatively close to the obstacle, the conditions for reducing engine torque can be made different from the predetermined conditions described above. This makes it possible to set appropriate conditions for ensuring good starting performance from a different perspective than avoiding collision with an obstacle.

[0088] Furthermore, when restarting after the ignition is turned off, if the vehicle is stationary and particularly close to an obstacle, it is possible to reduce engine torque even at a lower throttle opening. This ensures that the engine torque necessary for the vehicle to start is secured, while preventing the vehicle from running over an obstacle, such as a wheel stop located near the front of the vehicle, due to acceleration during starting.

[0089] Sixth, by estimating the distance from the vehicle to the obstacle and making it possible to store the estimated distance using a memory means, even when the obstacle is outside the field of view of the front camera 201 or the rear camera 202 and its presence cannot be directly detected, it becomes possible to determine the distance to the obstacle and appropriately determine whether the conditions for reducing engine torque have been met.

[0090] Although not described above, if the obstacles detected by the front camera 201 or rear camera 202 include obstacles higher than a predetermined height Hthr, the torque reduction obstacle distance Dthr may be shortened as the steering angle STR detected by the steering angle sensor 114 increases. The torque reduction obstacle distance Dthr can be shortened, for example, by setting a coefficient that tends to decrease as the steering angle STR increases and is less than 1, and multiplying the torque reduction obstacle distance Dthr obtained when torque reduction conditions A and C are set by this coefficient.

[0091] If the detected obstacles include tall obstacles and a change in steering angle occurs, it is assumed that the vehicle is attempting to avoid the obstacle by steering. In such cases, the larger the steering angle STR, the shorter the distance Dthr at which torque reduction is implemented. By not reducing engine torque while the vehicle is relatively far from the obstacle, and only reducing it when it gets closer to the obstacle, it is possible to avoid situations where the reduction in engine torque hinders obstacle avoidance.

[0092] In the above explanation, a monocular camera sensor was used as the external environment sensor. However, the external environment sensor that can be used is not limited to this; a stereo camera sensor or any other external environment sensor besides a camera may also be used. In other words, it is possible to use any appropriate external environment sensor that can output information that contributes to the identification of the type of obstacle, especially the height of the obstacle. [Explanation of Symbols]

[0093] 1...Vehicle engine torque suppression device, 101...Engine controller, 111...Accelerator opening sensor, 112fa...First (right front wheel) wheel speed sensor, 112fb...Second (left front wheel) wheel speed sensor, 112ra...Third (right rear wheel) wheel speed sensor, 112rb...Fourth (left rear wheel) wheel speed sensor, 113...Accelerometer, 114...Steering angle sensor, 121...Fuel injector, 201...Front camera (external sensor), 201a...Front camera detection unit, 201b...Front camera calculation unit, 202...Rear camera (external sensor), 211...Ignition switch (start switch), V...Vehicle (own vehicle), R...Front camera field of view, A...Front camera angle of view, OBS...Obstacles.

Claims

1. An obstacle detection means for detecting the presence of an obstacle in the direction of travel of the vehicle, Obstacle height detection means for detecting the height of the aforementioned obstacle, The system includes, when the presence of an obstacle is detected by the obstacle detection means, an engine torque suppression means that, under predetermined conditions, reduces the torque actually generated by the engine to a torque corresponding to the accelerator opening, The engine torque suppression device for a vehicle is configured such that the conditions for reducing the engine torque differ depending on whether the engine torque suppression means detects the presence of only obstacles higher than a predetermined height, the presence of only obstacles lower than a predetermined height, or the presence of both obstacles higher than a predetermined height and obstacles lower than a predetermined height.

2. The engine torque suppression means is When the accelerator opening is greater than or equal to a predetermined opening, the vehicle speed is less than or equal to a predetermined vehicle speed, and the distance to the obstacle is less than or equal to a predetermined distance, the engine torque is reduced. The engine torque suppression device for a vehicle according to claim 1, which, when detecting the presence of only obstacles lower than the predetermined height, reduces the predetermined opening, increases the predetermined vehicle speed, or shortens the predetermined distance compared to when detecting the presence of only obstacles higher than the predetermined height.

3. The engine torque suppression device for a vehicle according to claim 2, wherein when the engine torque suppression means detects the presence of only obstacles lower than the predetermined height, it reduces the predetermined opening angle during driving, increases the predetermined vehicle speed during reversing, or shortens the predetermined distance compared to when the presence of only obstacles higher than the predetermined height is detected.

4. The engine torque suppression means, when it detects the presence of both an obstacle higher than a predetermined height and an obstacle lower than a predetermined height that is closer to the vehicle than the obstacle higher than a predetermined height in the direction of travel of the vehicle, reduces the predetermined opening angle, increases the predetermined vehicle speed during reversing or shortens the predetermined distance, compared to the case where only the presence of an obstacle higher than a predetermined height is detected, and further shortens the predetermined distance during reversing when the vehicle speed is higher, compared to the case where only the presence of an obstacle lower than a predetermined height is detected.

5. The engine torque suppression device for a vehicle according to claim 1, wherein, when restarting after ignition is turned off, if the presence of the obstacle is not detected by the obstacle detection means or the vehicle is located closer to the obstacle than a predetermined distance, the engine torque is reduced under conditions different from the predetermined conditions.

6. The engine torque suppression device for a vehicle according to claim 2, wherein, upon restarting after ignition off, the presence of an obstacle is not detected by the obstacle detection means or the vehicle is located closer to the obstacle than the predetermined distance, the vehicle is stopped and the accelerator opening is greater than or equal to the predetermined opening.

7. The vehicle further comprises a steering angle detection means for detecting the steering angle of the vehicle, The engine torque suppression device for a vehicle according to claim 2, wherein the engine torque suppression means shortens the predetermined distance when the obstacle detected by the obstacle detection means includes an obstacle higher than the predetermined height, and the steering angle detected by the steering angle detection means is larger.

8. The obstacle detection means is an external sensor having a predetermined field of view or angle of view and installed facing the direction of travel of the vehicle. An obstacle distance estimation means detects the distance to the obstacle based on imaging information from the external sensor when the obstacle is within the field of view or angle of view, while estimating the distance to the obstacle based on the distance detected based on imaging information from the external sensor and the distance traveled by the vehicle after this distance is detected when the obstacle is outside the field of view or angle of view. The vehicle engine torque suppression device according to any one of claims 1 to 7, further comprising: a storage means for storing the distance estimated by the obstacle distance estimation means.

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