JP5594193B2 - Driving assistance device - Google Patents

Description

  The present invention relates to a driving support device that determines whether or not it is necessary to change a gear ratio of a transmission of a vehicle.

  Conventionally, a cruise control device is known as a driving support device for reducing a driving operation load on a driver. In a typical cruise control device, constant speed traveling control (auto cruise control) is performed to maintain the vehicle speed of the host vehicle constant. Constant-speed driving control means that the vehicle is driven at a constant vehicle speed range by adjusting the engine output and braking force according to the road gradient and driving load when driving on an automobile-only road such as an expressway or a regional high-standard road. Control.

  In recent years, a cruise control device has also been developed that performs follow-up running control (adaptive cruise control) that automatically keeps the distance between the vehicle and the preceding vehicle constant. Follow-up running control is control in which the engine output and braking force are adjusted in accordance with the inter-vehicle distance and relative speed so that the host vehicle follows the preceding vehicle. With these controls, the driving stability of the host vehicle is improved while reducing the burden on the driver's active accelerator operation and brake operation.

  By the way, the constant speed traveling control is control that is assumed to be performed in a steady traveling state. Therefore, even if the width of the vehicle speed range maintained by the constant speed traveling control is set to be relatively narrow, sufficient controllability is ensured. On the other hand, in the follow-up running control, the control content must be changed according to the behavior of the preceding vehicle, and acceleration / deceleration is performed in a relatively wide vehicle speed range. Therefore, a cruise control device equipped with a following traveling function is required to support a wide vehicle speed range.

On the other hand, in a vehicle equipped with a transmission (for example, a manual transmission, a semi-automatic, or the like) that performs a shifting operation by changing gear positions, a range of engine torque that can be covered by one gear position is determined. In other words, since the upper limit value of the torque necessary for the acceleration / deceleration of the vehicle is limited by the shift speed, it may not be possible to deal with a wide vehicle speed range.
Regarding such a problem, a technique for instructing a shift change of the transmission according to the traveling state of the host vehicle is known. For example, Patent Literature 1 describes a technique for displaying a shift-up instruction on a monitor based on the current engine torque (engine torque) and the maximum engine torque (maximum engine torque).

JP 61-122035 A

  However, it is not always possible to perform driving suitable for the driving environment with the conventional method of performing control according to the driving state of the host vehicle. For example, the magnitude of the acceleration / deceleration to be changed by the own vehicle differs depending on whether or not another vehicle is present around the own vehicle, that is, the timing at which the shift change should be performed varies depending on the traveling environment. . Therefore, in the control based only on the traveling state of the own vehicle, there is a problem that it is difficult to realize cooperative and stable traveling that matches the behavior of surrounding vehicles.

  In addition, the behavior of a vehicle that travels further ahead of the preceding vehicle of the host vehicle or a vehicle that travels in an adjacent lane may affect the future behavior of the preceding vehicle, and thus the future behavior of the host vehicle. There is sex. On the other hand, the conventional method does not consider such factors, so that there is a problem that response to changes in the surrounding driving environment is likely to be delayed and it is difficult to improve drive feeling.

One of the purposes of the present case was created in view of the above-described problems, and is to realize cooperative and stable traveling according to changes in the surrounding traveling environment.
The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) The driving assistance device disclosed herein is a driving assistance device for a vehicle equipped with a transmission, and a maximum torque of driving wheels according to a gear ratio and a required torque required for the driving wheels according to a traveling state. And a detecting means for detecting a traveling state of another vehicle around the host vehicle. In addition, a determination unit that determines whether or not the speed ratio needs to be changed is provided based on the maximum torque and the required torque calculated by the calculation unit and the traveling state detected by the detection unit.
The detection means includes virtual vehicle setting means for setting a virtual vehicle traveling in front of the vehicle based on a distance and a relative speed to the other vehicle existing within a predetermined range, and the calculation means The torque required to cause the vehicle to follow the virtual vehicle set by the virtual vehicle setting means is calculated as the required torque.
Further, when there are a plurality of other vehicles within the predetermined range, the virtual vehicle setting means determines the minimum distance and the minimum relative speed among the distances and relative speeds to the plurality of other vehicles as the virtual vehicle. It is determined that the virtual vehicle exists at the minimum relative speed at the position of the minimum distance.

For example, the determination means may determine whether or not it is necessary to change the shift speed of the transmission based on the maximum torque, the required torque, and the traveling state, and does not have a predetermined shift speed. In the case of a continuously variable transmission, it may be determined whether or not it is necessary to change the speed ratio itself.
Note that the calculation means may be configured to calculate the maximum torque of the engine and the required torque required for the engine in accordance with the running state and the gear ratio. The product of the maximum torque of the engine and the gear ratio (gear ratio of the gear) is proportional to the maximum torque of the drive wheels.

(2) It is preferable to provide notification means for notifying the passenger of the vehicle of the determination result by the determination means .

(3 ) The calculation means includes torque difference calculation means for calculating a difference between the maximum torque and the required torque, and the determination means performs the change according to the difference calculated by the torque difference calculation means. It is preferable to determine necessity.

( 4 ) It is preferable that the torque difference calculation means corrects the difference based on the traveling state detected by the detection means.
( 5 ) It is preferable that the determination unit changes a determination criterion related to the necessity of the change based on the traveling state detected by the detection unit.
( 6 ) Preferably, the determination means holds the determination when the clutch operation of the transmission is detected, and continues the determination when the clutch operation is not detected.

(7) and this with control means for controlling the speed ratio of the vehicle based on a determination result by the determining means is preferred.
( 8 ) Preferably, the calculating means calculates the maximum torque based on the gear ratio and the vehicle speed, and calculates the required torque based on the vehicle speed and a running resistance.

According to the disclosed driving assistance device, when determining whether or not the gear ratio needs to be changed, not only the information related to the torque of the host vehicle but also the running conditions of other surrounding vehicles can be referred to. Thereby, the timing which should change a gear ratio according to driving | running environment can be varied, and the appropriate judgment for implement | achieving the cooperative stable driving | running according to the behavior of the other vehicle can be implemented.
In addition, all the behaviors of other vehicles in the detection range can be reflected in the behavior of the virtual vehicle, the necessity of shift change can be determined earlier, and the response delay to the surrounding driving environment can be prevented. Can do.

It is a block block diagram which illustrates the whole structure of the driving assistance device which concerns on one Embodiment. (A), (b) is a top view which shows the driving | running | working condition of the vehicle provided with this driving assistance device together. It is a graph for demonstrating the determination in this driving assistance device. It is a flowchart which shows the example of control implemented by this driving assistance device, (a) is based on the minimum distance and minimum relative speed regarding the setting of a virtual vehicle, (b) shows what is based on the minimum target vehicle speed. It is a flowchart which shows the example of control implemented with this driving assistance device. It is a graph for demonstrating the control effect | action by this driving assistance device.

  The driving support device will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment.

[1. Device configuration]
FIG. 1 illustrates a vehicle 10 including a manual transmission 19 (manual transmission) as a vehicle to which the driving support device of the present embodiment is applied. The transmission 19 is connected to the output shaft of the engine 17 via the clutch 18. The rotational output of the engine 17 is input to the transmission 19 according to the connection / disconnection state of the clutch 18, and is transmitted to the downstream drive wheel side after being decelerated at a predetermined reduction ratio (transmission ratio, gear ratio). A transmission mechanism composed of a plurality of gears is provided inside the transmission 19, thereby setting a plurality of shift stages having different reduction ratios.

  The operating state of the engine 17 is controlled by the engine control device 11 (engine ECU). The engine control device 11 is an electronic control device that controls the amount of air supplied to the engine 17, the fuel injection amount, and the ignition timing. For example, the engine control device 11 is configured as an LSI device or an embedded electronic device in which a microprocessor, ROM, RAM, and the like are integrated. The The engine control device 11 calculates a control parameter based on signals transmitted from various sensors (not shown), and controls the engine 17 based on the control parameter.

  Specific control objects of the engine control device 11 include the amount of fuel injected from the injector, the injection timing, the ignition timing at the spark plug, the opening of the throttle valve, and the like. Further, specific examples of the control parameters calculated here include the engine speed Ne, the vehicle speed V, the intake flow rate Q, and the like. The engine speed Ne is calculated based on a signal from a crank angle sensor that detects the rotation angle of the crankshaft of the engine 17, for example. Further, the vehicle speed V is calculated based on, for example, a signal from a vehicle speed sensor, and the intake air flow rate Q is calculated based on, for example, a signal from an air flow sensor. Information about the engine speed Ne, the vehicle speed V, and the intake air flow rate Q calculated here is transmitted to the cruise control device 1 described later.

The vehicle 10 is provided with a shift position sensor 12, an accelerator opening sensor 13, a brake switch 14, and a clutch switch 15 as sensors for detecting an operation state by a driver. The shift position sensor 12 detects an operation position SP (shift position) of the shift lever. Note that the gear position of the transmission 19 is set according to the operation position SP of the shift lever. The accelerator opening sensor 13 detects the accelerator opening θ _AC corresponding to the amount of depression of the accelerator pedal. The accelerator opening degree θ _AC is a parameter corresponding to the driver's acceleration request.

The brake switch 14 detects whether or not the brake pedal is depressed. Here, for example, an ON signal (SW _BR = 1) is output when the brake pedal is depressed, and an OFF signal (SW _BR = 0) is output when there is no brake operation. Similarly, the clutch switch 15 detects whether or not the clutch pedal is depressed, and outputs an on / off signal (SW _CL = 1 or SW _CL = 0) according to the presence or absence of the clutch operation.
Information on the shift lever operation position SP, information on the accelerator opening degree θ _AC , and stepping operation information SW _BR and SW _CL detected by these sensors are transmitted to the cruise control control device 1.

  A millimeter wave radar 16 is provided at an arbitrary position of the vehicle 10. The millimeter wave radar 16 is a radar device that detects an object (another vehicle, an obstacle, or the like) existing around the vehicle 10. Here, FIG. 2A illustrates a state where the vehicle 10 is the host vehicle and another vehicle is traveling in front of the vehicle. The millimeter wave radar 16 is provided, for example, at the front end of the vehicle 10, and emits a millimeter wave toward a range indicated by a broken line in FIG. 2A and receives the reflected wave. That is, a range surrounded by a broken line is an object detection range by the millimeter wave radar 16. The detection range is an arbitrary area including at least the front of the vehicle 10.

  In the example of FIG. 2 (a), it is provided over a wide range in the vehicle width direction in front of the host vehicle, and extends not only on the lane in which the host vehicle travels but also on the lane adjacent to the traveling lane. The millimeter wave radar 16 includes an electronic control device, which analyzes the received reflected wave and detects the distance DR (inter-vehicle distance) and the relative speed VR to the object that reflects the millimeter wave. Information of the distance DR and the relative speed VR detected here is transmitted to the cruise control control device 1.

A cruise switch 6 and a notification device 7 are provided in the passenger compartment of the vehicle 10. The cruise switch 6 is an input device that is operated by the driver at the start of constant speed traveling control and follow-up traveling control, and is, for example, a two-position switch that outputs an on / off signal in accordance with the operation state. An output signal from the cruise switch 6 is transmitted to the cruise control control device 1.
The notification device 7 is an output device for notifying the driver of information related to constant speed traveling control and follow-up traveling control, and is, for example, a display device or a display lamp. In FIG. 1, a notification device 7 having a shift-up lamp 7a and a shift-down lamp 7b is shown.

  The cruise control control device 1 (cruise control ECU) is an electronic control device for performing constant speed travel control and follow-up travel control. For example, as with the engine control device 11, an LSI in which a microprocessor, ROM, RAM, etc. are integrated. Configured as a device or embedded electronic device. The cruise control control device 1 adjusts the engine output and the braking force based on information transmitted from various sensors and the traveling state of the vehicle 10, and performs constant speed traveling control and follow-up traveling control. In addition to these controls, the cruise control control apparatus 1 of the present embodiment determines whether or not the gear position of the transmission 19 is appropriate when the constant speed traveling control and the follow traveling control are performed. Implement control.

[2. Overview of control]
An outline of the three types of control performed by the cruise control control device 1 will be described.
[2-1. Constant speed travel control]
In the constant speed running control, the engine output and the braking force are adjusted so as to keep the vehicle speed V constant. For example, the vehicle speed V of when the cruise switch 6 is turned on is detected by the cruise control device 1, which is stored as a reference vehicle speed V _0.

Further, the cruise control control device 1 calculates the magnitude of torque required to drive the vehicle 10 at the reference vehicle speed V ₀ according to the actual change in the vehicle speed V, the change in the road surface gradient, and the change in the external load, This is transmitted to the engine control device 11 as a constant speed required torque.
On the other hand, the engine control device 11 receives this and controls the fuel injection amount, the injection timing, the ignition timing, the intake air amount, etc. so that the engine 17 generates the constant speed required torque requested from the cruise control control device 1. To do.

Further, when an accelerator operation is performed during the constant speed traveling control, a torque corresponding to the accelerator operation amount θ _AC is added and the engine 17 is controlled so that a larger torque is generated in the engine 17. For example, the cruise switch 6 is turned off, the output signal of the brake switch 14 is an on signal (SW _BR = 1), and the output signal of the clutch switch 15 is an on signal ( SW _CL = 1). In the present embodiment, the constant speed traveling control ends when any of these conditions is satisfied.

[2-2. Follow-up control]
The follow-up running control is a control that adjusts the engine output and the braking force so that the distance between the preceding vehicle and the preceding vehicle is constant when the preceding vehicle exists in front of the vehicle 10 when the constant speed running control is performed. is there. For example, when the own vehicle gradually catches up with the preceding vehicle during the constant speed traveling control and the preceding vehicle enters the detection range of the millimeter wave radar 16, the following traveling control is performed in addition to the constant speed traveling control.

At this time, the cruise control control device 1 changes the torque and the distance DR required to maintain the distance DR at a predetermined value based on the distance DR and the relative speed VR detected by the millimeter wave radar 16 and the vehicle speed V of the host vehicle. The time required for the operation and the torque required for setting the relative speed VR to 0 are calculated and transmitted to the engine control device 11 as the follow-up request torque. On the other hand, the engine control device 11 receives this, and controls the fuel injection amount, the injection timing, the ignition timing, the intake air amount, etc. so that the follow-up request torque requested from the cruise control control device 1 is generated in the engine 17. .
Examples of the termination condition of the follow-up traveling control include that the constant speed traveling control termination condition is satisfied, and that no preceding vehicle is detected within the detection range of the millimeter wave radar 16.

[2-3. Shift speed determination control]
The gear position determination control is control that is executed in a state where constant speed traveling control or follow-up traveling control is being performed. In this control, it is determined whether the cruise control control device 1 can cover the constant speed required torque required in the constant speed traveling control or the required tracking torque required in the following traveling control by the gear position of the transmission 19 at that time. The determination result is displayed on the notification device 7.

  For example, when a large follow-up request torque is required to follow an accelerated preceding vehicle, if it is determined that sufficient torque cannot be obtained at the gear position at that time, the cruise control control device 1 causes the shift down lamp 7b is lit to prompt the driver to shift down. In addition, for example, when it is determined that sufficient torque cannot be obtained due to a decrease in the vehicle speed V during continuous uphill travel, guidance is provided to prompt the driver to shift down. On the other hand, for example, when it is determined that there is a surplus in torque due to an increase in the vehicle speed V during continuous downhill travel (that is, when it is desired to increase the number of revolutions transmitted to the drive wheels from the transmission 19). Is instructed to encourage the driver to shift up.

Further, in the shift speed determination control according to the present embodiment, the end condition of the constant speed traveling control is changed when guidance for upshifting or downshifting is performed. For example, constant speed travel control is terminated by depressing the clutch pedal during normal operation, but constant speed travel control is temporarily canceled by clutch operation during guidance, and constant speed travel control continues again after the clutch operation is completed. Is done. That is, even if the output signal of the clutch switch 15 becomes an ON signal, a resume function is provided that automatically returns the constant speed traveling control when the output signal becomes an OFF signal again.
Hereinafter, a specific control configuration for carrying out the shift speed determination control will be described.

[3. Control configuration]
The cruise control control device 1 is provided with a detection unit 2, a calculation unit 3, a determination unit 4 and a notification unit 5 in order to realize a shift speed determination control function. The functions of the detection unit 2, the calculation unit 3, the determination unit 4, and the notification unit 5 may be realized by an electronic circuit (hardware), may be programmed as software, or may be A part of the functions may be provided as hardware and the other part may be software.

[3-1. Detection unit]
The detection unit 2 (detection means) detects the traveling state of other vehicles around the host vehicle. Here, the distance DR and the relative speed VR are calculated for each object existing within the detection range of the millimeter wave radar 16, and a virtual vehicle (virtual preceding vehicle) is set from the information. As a function for setting a virtual vehicle, the detection unit 2 includes a distance detection unit 2a, a relative speed detection unit 2b, and a virtual vehicle setting unit 2c.

The distance detection unit 2a detects the distance DR to the own vehicle for each object existing within the detection range of the millimeter wave radar 16. For example, as shown in FIG. 2A, when there are three other vehicles (vehicle A, vehicle B, and vehicle C) within the detection range of the millimeter wave radar 16, the distance detector 2a has three distances DR. Detect _A , DR _B and DR _C. Information of all the distances DR detected here is transmitted to the virtual vehicle setting unit 2c.

The relative speed detection unit 2b detects the host vehicle and the relative speed VR for each object existing within the detection range of the millimeter wave radar 16. In the example of FIG. 2A, the relative speed detector 2b detects the relative speeds VR _A , VR _B and VR _C of the vehicles A, B and C, respectively. Note that the sign of the relative speed VR is positive in the traveling direction of the host vehicle. Information on all the relative speeds VR detected here is transmitted to the virtual vehicle setting unit 2c.

The virtual vehicle setting unit 2c (virtual vehicle setting means) selects the smallest distance DR _MIN among all the distances DR detected by the distance detection unit 2a, and sets this as the position of the virtual vehicle. The set value of the relative speed of the virtual vehicle is set to the smallest relative speed VR _MIN among all the relative speeds VR detected by the relative speed detector 2b.

For example, assuming that the distance DR _A to the vehicle _A is the smallest and the relative speed VR _B of the vehicle B is the smallest in the running situation shown in FIG. 2A, the virtual vehicle setting unit 2c is driven by the vehicle A. It is determined that the virtual vehicle is present at the relative distance VR _B of the vehicle B at the position of the distance DR _A. The virtual vehicle set by the virtual vehicle setting unit 2c corresponds to the vehicle D in FIG. The distance DR _MIN to the virtual vehicle and the relative speed VR _MIN set here are transmitted to the calculation unit 3.

[3-2. Calculation unit]
The calculation unit 3 (calculation means) performs torque calculation used in constant speed traveling control and follow-up traveling control. Here, a maximum torque calculator 3a, a required torque calculator 3b, and a torque difference calculator 3c are provided.
The maximum torque calculation unit 3a calculates the maximum torque T _MAX of the drive wheels corresponding to the gear position of the transmission 19.

The maximum torque calculation unit 3a stores in advance a correspondence relationship between the engine speed Ne of the engine 17 and the maximum engine torque T _MAXENG that can be generated at that time (for example, the engine torque in the previous throttle state). Using this correspondence, the maximum torque calculator 3a calculates the maximum engine torque T _MAXENG based on the engine speed Ne. Further, the maximum torque calculator 3a multiplies the maximum engine torque T _MAXENG by the gear ratio of the gear stage at that time to calculate the maximum torque T _MAX that can be transmitted to the drive wheel side from the transmission 19.

The rotational speed on the drive wheel side can be calculated from the engine rotational speed Ne and the gear ratio, and the rotational speed on the drive wheel side corresponds to the vehicle speed V of the vehicle 10. Therefore, the maximum torque T _MAX may be obtained from the gear position and the vehicle speed V. The maximum torque T _MAX calculated here is transmitted to the torque difference calculation unit 3c.

The required torque calculator 3b calculates a required torque T _REQ required for the drive wheels. Here, a torque having a magnitude corresponding to the driving force required based on the traveling state of the vehicle 10 is calculated as the required torque T _REQ . For example, it is conceivable to calculate the required torque T _REQ based on the vehicle speed V and running resistance (road surface resistance, wind resistance, road surface gradient, etc.). Alternatively, the target torque calculated by the engine control device 11 based on the engine speed Ne and the intake air flow rate Q may be converted into a drive torque by the gear ratio of the gear stage at that time, and this may be used as the required torque T _REQ. It is done. The requested torque T _REQ calculated here is transmitted to the torque difference calculation unit 3c.

The required torque T _REQ includes torque given as the vehicle speed V of the vehicle 10 changes, torque given by an acceleration request, deceleration request, and the like. Specifically, the following torque is included. . (1) corresponds to the above-described constant speed required torque, and (2) and (3) correspond to the above-described follow-up required torque.
(1) Torque for maintaining a constant vehicle speed V regardless of road gradient during constant speed travel control (2) Torque for traveling at the same speed as the preceding vehicle during follow-up travel control (3) During follow-up travel control Torque to maintain a certain distance between the vehicle and the preceding vehicle

For example, when the road surface gradient increases and the vehicle speed V starts to decrease during traveling at a constant speed, the required torque calculation unit 3b calculates the required torque T _REQ including the torque required to increase the decreased vehicle speed V. Further, when the virtual vehicle is set by the virtual vehicle setting unit 2c during the follow-up traveling control, the required torque calculation unit 3b calculates the torque required to set the relative speed VR _MIN with the virtual vehicle to 0 and the distance to the virtual vehicle. A torque required to set DR _MIN to a predetermined value is calculated, and a required torque T _REQ including these is calculated. As described above, the required torque calculation unit 3b functions to correct the required torque T _REQ based on the behavior of the virtual vehicle in which the traveling state of the other vehicle detected by the detection unit 2 is reflected.

Further, the required torque T _REQ calculated here is also transmitted to the engine control device 11. As a result, the operating state of the engine 17 is controlled, and the fuel amount, injection timing, ignition timing, intake air amount, and the like for achieving constant speed traveling control and follow-up traveling control are appropriately adjusted.

Torque difference calculation section 3c (torque difference calculation means), a maximum torque T _MAX calculated by the maximum torque calculating section 3a, based on the required torque T _REQ calculated by the required torque calculating unit 3b, between these torques An index value for determining the magnitude of the difference is calculated. The torque difference calculation unit 3c of the present embodiment calculates a torque difference ΔT (= T _MAX −T _REQ ) obtained by subtracting the required torque T _REQ from the maximum torque T _MAX as the index value. The torque difference ΔT increases as the engine torque margin increases and decreases as the margin decreases. Further, when the torque difference ΔT is 0, it means that a driving torque equal to the required torque T _REQ is transmitted to the downstream side of the transmission 19. The torque difference ΔT calculated here is transmitted to the determination unit 4.

It can be said that the torque difference calculation unit 3c calculates the torque difference ΔT using the required torque T _REQ corrected based on the behavior of the virtual vehicle. Therefore, it can be said that the torque difference calculation unit 3c functions to correct the torque difference ΔT based on the traveling state of the other vehicle detected by the detection unit 2.

[3-3. Judgment unit]
The determination unit 4 (determination means) determines whether or not it is necessary to change the gear position based on the maximum torque T _MAX , the required torque T _REQ, and the traveling state of the vehicle 10. For example, determination according to the value of the torque difference ΔT calculated by the torque difference calculation unit 3c is performed. That is, the determination unit 4 determines that a downshift is necessary when the torque difference ΔT is less than the first threshold T _A (T _A > 0). On the other hand, it determines that the torque difference ΔT when it second threshold value T _B or greater than the first threshold value T _A is the shift-up is necessary.
Further, the torque difference ΔT when it is less than the first threshold value T _A or more and the second threshold value T _B is determined that the change of the gear position is not required. Incidentally, the first threshold value T _A and the second threshold value T _B is a preset value for each gear position according to the vehicle speed V and the engine rotational speed Ne. The result determined here is transmitted to the notification unit 5.

Here, a specific determination example in the determination unit 4 will be described with reference to FIG. A graph L ₁ indicated by a bold solid line in FIG. 3 shows the relationship among the vehicle speed V, the road surface gradient, and the torque transmitted to the drive wheel side in a state where the shift stage of the transmission 19 is fixed. When the vehicle speed is V ₁ and the road surface gradient is 0 [%], the traveling state of the vehicle 10 is represented by the position of point P, and the torque transmitted to the drive wheel side from the transmission 19 is T ₁ . . The torque T ₂ of the when the vehicle speed is V ₁ in the graph L ₁ corresponds to the maximum torque T _MAX. Since the torque T ₁ of the vehicle that travels normally in the state of the point P corresponds to the required torque T _REQ , the torque difference ΔT is T ₂ −T ₁ , that is, corresponds to the distance from the point P to the point Q. Therefore, the determination unit 4 can be regarded as determining the magnitude of this distance.

The broken line in FIG. 3 is a graph L ₂ showing the variation of the value obtained by subtracting the first threshold value T _A from the graph L _1, the second threshold T dashed line in FIG. 3 from the graph L _{1 B} is a graph L ₃ showing the variation of the subtracted value a. That is, the graph L ₁ and L longitudinal axis width between ₂ corresponds to the magnitude of the first threshold value T _A, the graph L ₁ and L the longitudinal axis of width between ₃ the second threshold value T Corresponds to the size of _B. Here, assuming an area divided into _three by the graphs L ₂ and L ₃ , it is determined whether or not it is necessary to change the gear position by determining the type of the area including the point corresponding to the traveling state of the vehicle 10. It is possible.

That is, when the point corresponding to the running state of the vehicle 10 is located above the graph L _2, it is determined that the shift-down is necessary, when located between the graph L ₁ and Graph L ₂ Is determined to be unnecessary to change the gear position. Further, when located below the graph L ₂ is shifted up is determined to be necessary.

[3-4. Notification Department]
The notification unit 5 (notification unit) outputs a control signal to the notification device in accordance with the determination result in the determination unit 4 to notify the passenger and driver of the vehicle 10. For example, when it is determined that the upshift is necessary, the upshift lamp 7a is turned on, and when it is determined that the downshift is necessary, the downshift lamp 7b is turned on.
In addition, the notification unit 5 outputs a signal for changing the end condition to a control means for constant speed traveling control (not shown) and the engine control device 11. Thereby, even if the driver operates the clutch pedal and the shift lever to change the gear position, the constant speed traveling control is continued immediately after that.

[4. flowchart]
[4-1. Constant speed running control / following running control]
FIG. 4A is a flowchart illustrating a procedure of detecting a traveling state of another vehicle around the vehicle in the control executed by the cruise control control device 1. This flow is repeatedly executed at a predetermined cycle during the constant speed traveling control.

In step A 10, the detection result by the millimeter wave radar 16 is input to the cruise control control device 1. In the subsequent step A20, it is determined whether or not another vehicle exists within the object detection range by the millimeter wave radar 16. If no other vehicle is present, the process proceeds to step A100 and only constant speed traveling control is continued. In the constant speed running control, a constant speed required torque required to maintain the vehicle speed V at the reference vehicle speed V ₀ is calculated and transmitted to the engine control device 11. Thus, the fuel injection amount, the injection timing, the ignition timing, the intake air amount, etc. are adjusted so that the vehicle 10 travels at a constant speed.

On the other hand, when another vehicle exists, the process proceeds from step A20 to step A30, and the follow-up running control is started. In subsequent step A40, the distance detection unit 2a calculates the distance DR to each other vehicle existing within the detection range. Further, in the relative speed detection unit 2b, the relative speed VR of each other vehicle existing within the detection range is calculated. Thereafter, in step A50, the virtual vehicle setting unit 2c selects the smallest distance DR _MIN among all the distances DR and the smallest relative speed VR _MIN among all the relative speeds VR, and sets the virtual vehicle. The tracking target of the vehicle 10 is this virtual vehicle. Further, the distance DR _MIN to the virtual vehicle and the relative speed VR _MIN are transmitted to the calculation unit 3.

In step A60, the required torque T _REQ is calculated in the required torque calculation unit 3b based on the distance DR _MIN to the virtual vehicle and the relative speed VR _MIN . The value of the requested torque T _REQ calculated here changes according to the behavior of the virtual vehicle. For example, when the vehicle B has not been braked in the state shown in FIG. 2A, but the vehicle A has not yet been braked, the virtual vehicle that is the target of the vehicle 10 has been braked. A determination is made and the required torque T _REQ is calculated accordingly. When the vehicles A to C are accelerated, the distance DR _MIN to the virtual vehicle and the relative speed VR _MIN are also increased, and the required torque T _REQ for following this is calculated.
In step A70, the required torque T _REQ is transmitted to the engine control device 11, and the fuel injection amount, injection timing, ignition timing, intake air amount, etc. are adjusted so that the vehicle 10 follows the virtual vehicle.

[4-2. Shift speed determination control]
FIG. 5 is a flowchart illustrating the control content executed in the cruise control control device 1 in parallel with the control as shown in FIG. Here, the shift speed determination control when the constant speed traveling control and the follow traveling control are performed will be described.

In Step B10, the required torque T _REQ calculated by the required torque calculation unit 3b is input to the torque difference calculation unit 3c. When the follow-up travel control is not performed, the constant speed required torque related to the constant speed travel control is input to the torque difference calculation unit 3c as the required torque _TREQ .
In the subsequent step B20, the maximum torque T _MAX corresponding to the gear position of the transmission 19 is calculated in the maximum torque calculator 3a and input to the torque difference calculator 3c. In response to this, the torque difference calculation unit 3c calculates a torque difference ΔT (= T _MAX −T _REQ ) obtained by subtracting the required torque T _REQ from the maximum torque T _MAX .

In Step B30, the determination unit 4 determines whether or not the maximum torque _TMAX is insufficient with respect to the required torque _TREQ . Here, by comparing the torque difference ΔT with the first threshold value T _A , it is determined that the torque is insufficient when ΔT <T _A , and it is determined that a downshift is necessary. Proceed to In step B40, a control signal is output from the notification unit 5 to the notification device 7, and the downshift lamp 7b is turned on.

On the other hand, in the case of [Delta] T ≧ T _A in step B30, the processing proceeds to step B50. In Step B50, the determination unit 4 determines whether or not the maximum torque _TMAX is excessive with respect to the required torque _TREQ . Here, by comparing the torque difference ΔT with the second threshold value T _B , it is determined that the torque is excessive when ΔT ≧ T _B, it is determined that the upshift is necessary, and the process goes to Step B60. move on. In step B60, a control signal is output from the notification unit 5 to the notification device 7, and the upshift lamp 7a is turned on.
Further, if ΔT <T _B in Step B50, that is, if T _A ≦ ΔT <T _B , it is determined that there is no need to change the gear position. Therefore, this flow ends without a control signal being output from the notification unit 5 to the notification device 7.

[5. Action]
[5-1. Shift change judgment during constant speed traveling control]
The control action by the driving assistance device will be described. FIG. 6 is a graph showing the relationship between the maximum driving force of the drive wheels and the vehicle speed V of the vehicle 10 in which the running resistance due to the road surface gradient is superimposed on the graph for each shift stage.
When the vehicle speed is V ₁ and the road surface gradient is 0 [%], the traveling state of the vehicle 10 is represented by the position of the point X. The traveling state at this point X corresponds to the traveling state at point P in FIG. 3, and the driving force in this state is F ₁ . The gear stage of the vehicle 10 is 5th. When cruise switch 6 is turned on by the driver where the vehicle speed V ₁ is stored as a reference vehicle speed V _0, the constant-speed running control is started. Thus, the engine output is adjusted to maintain the vehicle speed V _1, the vehicle 10 travels at a constant speed.

When the road surface gradient changes in the uphill direction during the constant speed traveling control, the traveling state of the vehicle 10 moves upward in FIG. Assuming that the road surface gradient becomes 7%, the traveling state moves to the position of point Y along the white arrow in the figure, and the driving is greater than the maximum driving force F ₂ at the fifth speed. Force is required from the vehicle 10. As a result, the torque becomes insufficient and the vehicle speed V ₁ cannot be maintained.

On the other hand, in the above-described driving support device, the shift speed determination control is performed together with the constant speed traveling control. That is, in the process of the operating state of the vehicle 10 moves from point X to point Y, is compared with the required torque T _REQ and the maximum torque T _MAX, if the torque difference ΔT becomes less than the first threshold value T _A There will be guidance for downshifting. Thus, when the downshift to the fourth speed is operated at the point W located below the maximum driving force, the torque shortage is solved.

Further, in the above-described driving support device, in such a shift change process, the constant speed traveling control is temporarily canceled only when the output signal of the clutch switch 15 is an on signal, and the output signal becomes an off signal again. The constant speed running control is restored. Thus, the running state of the vehicle 10 will be moved toward the continuing point Y from the point W, the vehicle 10 while maintaining the vehicle speed V _1, a road surface gradient is traveling uphill of 7%.

[5-2. Shift change judgment during follow-up driving control]
When another vehicle is detected within the object detection range by the millimeter wave radar 16 in a state where the vehicle 10 is located at the point X, follow-up traveling control based on the traveling state of the other vehicle is started. In the follow-up running control, the distance DR to the other vehicle and the relative speed VR are calculated, and the virtual vehicle is set from the information. The set values of the distance to the virtual vehicle and the relative speed are the smallest distance DR _MIN and the relative speed VR _MIN among the information on all other vehicles detected by the millimeter wave radar 16.

As a result, not only the preceding vehicle traveling immediately in front of the vehicle 10, but also the overall traveling state ahead is reflected in the traveling state of the virtual vehicle. In addition, since the detection range of the millimeter wave radar 16 is provided over a wide range in the vehicle width direction, the traveling state of the other vehicle traveling in the adjacent lane is also reflected in the traveling state of the virtual vehicle. When the vehicle speed of the virtual vehicle is V ₁ , the vehicle 10 follows this, and continues the following traveling control so as to maintain the vehicle speed V ₁ and a predetermined inter-vehicle distance.

Further, when the virtual vehicle suddenly accelerates from the vehicle speed V ₁ to the vehicle speed V ₂ , the distance DR _MIN to the virtual vehicle and the relative speed VR _MIN increase. Thus, the calculation unit 3 calculates the torque required to set the distance DR _MIN to a predetermined value and the torque required to set the relative speed VR _MIN to 0, and these torques are reflected in the required torque T _REQ. . On the other hand, in the vehicle 10 with the fifth gear, the driving force necessary for acceleration is insufficient, the acceleration is delayed, and the inter-vehicle distance may be increased.

On the other hand, in the above driving assistance device, the required torque T _REQ set in accordance with the traveling state of the virtual vehicle is compared with the maximum torque T _MAX, and the torque difference ΔT is less than the first threshold T _A There will be guidance for downshifting. Thereby, in the process in which the traveling state of the vehicle 10 moves along the black arrow in the figure, if the downshift to the fourth speed is operated at the point U located below the maximum driving force, sufficient for acceleration Driving force is ensured, and follow-up response is ensured.

When the distance DR _MIN and the relative speed VR _MIN decrease due to the acceleration of the vehicle 10, the required torque T _REQ decreases accordingly, and the maximum torque T _MAX at the fourth speed is sufficiently secured. Furthermore, the vehicle 10 is overtaking the virtual vehicle, in the process leading to the state of point a predetermined inter-vehicle distance at the vehicle speed V ₂ is maintained Z, when the torque difference ΔT becomes equal to or higher than the second threshold value T _B, the shift-up guidance Is made. As a result, the engine speed Ne decreases while a sufficient maximum driving force is secured, and constant speed traveling control and follow-up traveling control are continued while maintaining the state of the point Z.

[6. effect]
As described above, when determining whether or not a shift change is necessary, the above-described driving support device can refer not only to information related to the torque of the host vehicle but also to the driving conditions of other surrounding vehicles. Accordingly, the timing at which the gear position (that is, the gear ratio) should be changed according to the driving environment can be made different, and an appropriate determination for realizing cooperative and stable driving according to the behavior of the other vehicle is performed. be able to.

  Further, by notifying the occupant and the driver of the result determined by the determination unit 4 with the notification device 7, it is possible to prompt the driver to perform driving suitable for the driving environment, and improve the drive feeling while surrounding vehicles. It is possible to realize cooperative and stable driving that matches the behavior of the car.

  Furthermore, in the above-described driving support device, a virtual vehicle is set instead of using the object detected by the millimeter wave radar 16 as it is. Thereby, the necessity of a shift change can be determined at an earlier stage, and a response delay with respect to the surrounding traveling environment can be prevented. For example, not only the sudden braking of the vehicle A shown in FIG. 2A but also the sudden braking of the vehicle B can be dealt with, and the stable running performance of the vehicle can be improved. Further, it is possible to quickly cope with an interruption operation of another vehicle that travels in an adjacent lane like the vehicle C.

Further, in the above-described driving support device, the minimum distance DR _MIN and the minimum relative speed VR _MIN of all objects detected by the millimeter wave radar 16 are used as set values of the distance to the virtual vehicle and the relative speed. Thereby, all the behaviors of the other vehicles within the detection range can be reflected in the follow-up traveling control performed by the cruise control control device 1 and the necessity determination of the shift change of the vehicle (shift speed determination control).

Further, when determining whether or not a shift change is necessary, the torque difference calculation unit 3c calculates the torque difference ΔT between the maximum torque T _MAX and the required torque T _REQ , so that an appropriate gear position (that is, an appropriate gear ratio) can be accurately determined. Therefore, it is possible to improve the accuracy of determining whether or not it is necessary to change the gear position (speed ratio). In particular, it is possible to accurately determine whether or not a shift change is required at the time of acceleration / deceleration during which the magnitude of torque may have a great influence on drive feeling.

Further, in the above-described driving support device, the required torque T _REQ is corrected based on the traveling state of the other vehicle detected by the detection unit 2, and the torque difference ΔT related to the determination is calculated using the required torque T _REQ. Yes. As described above, by correcting the torque difference ΔT according to the driving environment around the vehicle 10, the driving state of the vehicle 10 can be easily followed to the surrounding driving situation, and more stable and stable driving is realized. can do.

  Further, in the above-described driving support device, the end condition of the constant speed traveling control is changed when it is determined by the shift speed determination control that the shift speed needs to be changed. In other words, in a situation where it is desired to change the gear position, even if the output signal of the clutch switch 15 is turned on, the constant speed running control is not terminated and the constant speed running control is performed when the output signal is turned off again. Is automatically restored.

  By such control, the operation of the driver can be reduced and the operability can be improved. Further, not only the constant speed traveling control but also the gear position determining control is not ended by the clutch operation, so that it is possible to determine the shift timing in any range, any gear ratio, and any traveling state of the transmission 19. There is. For example, as in the transition from the point X to the point Z shown in FIG. 6, it is possible to continuously perform the downshift determination and the upshift determination.

Further, in the above driving assistance device, the maximum torque T _MAX and the required torque T _REQ are calculated using parameters related to the driving force downstream of the transmission 19, such as the vehicle speed V, the shift speed, and the travel resistance. Thus, it is possible to determine whether or not an accurate shift change is necessary in accordance with the actual driving state of the vehicle 10.

[7. Modified example]
Regardless of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each structure of this embodiment can be selected as needed, or may be combined appropriately.
In the above embodiment, the first threshold value T _A and the second threshold value T _B according to the determination of the torque difference ΔT in the determination section 4, in advance for each shift speed according to the engine speed Ne (vehicle speed V) Although the set value is exemplified, the determination condition setting method is not limited to this. For example, it is conceivable to change the first threshold T _A and the second threshold T _B using the distance DR and the relative speed VR detected by the detection unit 2.

The distance DR and the relative speed VR are detected by the detection unit 2 when the follow-up running control is performed. The follow-up running control requires high responsiveness to the behavior of the virtual vehicle. That is, the required acceleration and deceleration ranges are larger than when only the constant speed traveling control is performed, and it is necessary to secure a larger torque margin. From this point of view, it may be configured to correct the first threshold value T _A and the second threshold value T _B at the time of implementation of the following distance control at a distance DR and the relative velocity VR.

For example, as the distance DR or relative velocity VR is low, it is conceivable to set a small first threshold T _A. In this case, a change in the shift speed in the shift-down direction is easily promoted, and a torque margin is easily secured. Also, as the distance DR or relative velocity VR is low, it is conceivable to set a small second threshold value T _B. In this case, it is difficult to change the gear position in the shift-up direction, and it is possible to suppress a decrease in driving force accompanying the change of the gear position. In this way, by changing the determination criterion according to the surrounding situation detected by the millimeter wave radar 16, it is possible to prompt the driver to drive more suitable for the driving environment.

In the above-described embodiment, the maximum torque T _MAX of the drive wheels corresponding to the gear position of the transmission 19 is calculated in the maximum torque calculator 3a. This maximum torque T _MAX corresponds to a value obtained by amplifying the maximum torque of the engine 17 in the operation state at that time with a gear ratio corresponding to the gear position. That is, the product of the maximum torque of the engine 17 and the gear ratio of the shift speed is proportional to the maximum torque of the drive wheels. Therefore, the maximum torque of the engine 17 may be used instead of the maximum torque T _MAX of the drive wheel.

Similarly, the required torque calculation unit 3b may calculate the required torque required for the engine 17 instead of the required torque T _{REQ for} the drive wheels. That is, the required torque required for the engine 17 is calculated according to the shift state and the shift speed. For example, it is conceivable to calculate the required torque by converting the torque corresponding to the driving force required for the driving wheel by the gear ratio. Regardless of the calculation method of the maximum torque and the required torque, it can be determined whether or not the required torque is within a sufficient engine torque range covered by the gear position at that time.

Further, the torque difference calculation section 3c of the above-described embodiments, but calculates the torque difference ΔT between the maximum torque T _MAX and the required torque T _REQ, to determine the magnitude relationship between the maximum torque T _MAX and the demand torque T _REQ However, the index value is not limited to this. For example, the configuration may be such that the ratio of the required torque T _REQ to the maximum torque T _MAX is calculated. In this case, the closer the ratio is to 1, the smaller the engine torque margin can be determined.

In the above-described embodiment, the case where the virtual vehicle is set using the minimum distance DR _MIN and the relative speed VR _MIN within the detection range of the millimeter wave radar 16 has been described, but a specific method for setting the virtual vehicle is described below. It is not limited to this. For example, the target vehicle speed of the vehicle 10 with respect to each other vehicle existing within the detection range of the millimeter wave radar 16 may be calculated, and the other vehicle having the minimum target vehicle speed may be a virtual vehicle. Further, the required torque T _REQ may be calculated based on the target vehicle speed.

The flowchart shown in FIG. 4B illustrates a control procedure when the required torque T _REQ is calculated using the target vehicle speed. Steps common to the flowchart shown in FIG. 4A are given the same step numbers and description thereof is omitted.

In step A45, the target vehicle speed VI to each other vehicle is calculated based on the relative speed VR of each other vehicle calculated in step A40. In the subsequent step A55, the smallest target vehicle speed VI _MIN is selected from all the target vehicle speeds VI, and the other vehicle that is the target of the target vehicle speed VI _MIN is set as a virtual vehicle.
In step A65, the required torque T _REQ is calculated in the required torque calculator 3b based on the target vehicle speed VI _MIN required to follow the virtual vehicle. In step A70, the required torque T _REQ is transmitted to the engine control device 11, and the fuel injection amount, injection timing, ignition timing, intake air amount, etc. are adjusted so that the vehicle 10 follows the virtual vehicle. Even in such a calculation, it is possible to determine early whether or not a shift change is necessary according to the behavior of the virtual vehicle, and it is possible to prevent a delay in acceleration and deceleration with respect to the surrounding traveling environment.

  Further, in the above-described embodiment, the driving support device in the vehicle 10 of the manual transmission is illustrated, but the specific type of the transmission 19 is not limited to this. The transmission may be at least a transmission having a plurality of shift stages or a transmission having a plurality of transmission ratios, and can be applied to a semi-automatic transmission, an automatic transmission, and a continuously variable transmission. Further, in the case of a transmission having a mechanism for changing the gear position without manual operation, the gear position can be controlled based on the determination result by the determination unit 4. For example, the notification unit 5 may function as a control unit that controls the shift stage of the automatic transmission. As a result, it is possible to perform a shift change without delay, and it is possible to more reliably realize cooperative and stable traveling according to the behavior of other vehicles.

  Moreover, in the above-mentioned embodiment, although what performed the necessity determination of a shift change in the cruise control control apparatus 1 provided independently from the engine control apparatus 11 was illustrated, it becomes a main body which implements a necessity determination. The control device is arbitrary, and may be, for example, the engine control device 11 or another electronic control device.

1 Cruise control control device (cruise control ECU)
2 Detection part (detection means)
2a Distance detection unit 2b Relative speed detection unit 2c Virtual vehicle setting unit (virtual vehicle setting means)
3. Calculation unit (calculation means)
3a Maximum torque calculation unit 3b Required torque calculation unit 3c Torque difference calculation unit (torque difference calculation means)
4. Judgment part (determination means)
5 Notification section (notification means, control means)
6 Cruise switch 7 Notification device

Claims (8)

In a driving support device for a vehicle equipped with a transmission,
Computing means for computing the maximum torque of the drive wheel according to the gear ratio and the required torque required for the drive wheel according to the running state;
Detecting means for detecting a running situation of other vehicles around the vehicle;
Determination means for determining whether or not it is necessary to change the speed ratio based on the maximum torque and the required torque calculated by the calculation means and the traveling state detected by the detection means ;
The detection means includes virtual vehicle setting means for setting a virtual vehicle traveling in front of the vehicle based on a distance and a relative speed to the other vehicle existing within a predetermined range;
The calculation means calculates, as the required torque, a torque required to cause the virtual vehicle set by the virtual vehicle setting means to follow the vehicle,
When there are a plurality of other vehicles within the predetermined range, the virtual vehicle setting means determines the minimum distance and the minimum relative speed among the distances and relative speeds to the plurality of other vehicles. The driving support apparatus, characterized in that the virtual vehicle is set as a distance and a relative speed, and the virtual vehicle is present at the minimum distance at the minimum relative speed . The driving support apparatus according to claim 1, further comprising a notification unit that notifies a passenger of the vehicle of a determination result by the determination unit. The calculating means includes a torque difference calculating means for calculating a difference between the maximum torque and the required torque;
It said determination means, and judging the necessity of the change in response to the difference calculated by the torque difference calculating means, the driving support apparatus according to claim 1 or 2, wherein. 4. The driving assistance apparatus according to claim 3 , wherein the torque difference calculation means corrects the difference based on the traveling state detected by the detection means. 5. The driving support apparatus according to claim 3 , wherein the determination unit changes a determination criterion related to the necessity of the change based on the traveling state detected by the detection unit. The determining means, the clutch operation of the transmission is pending the determination when it is detected, characterized by continuing said determination when the clutch operation becomes undetected, claims 1 to 5 The driving support device according to any one of the above. Wherein characterized by comprising a control means for controlling a speed ratio of the vehicle based on the determination result by the determining means, the driving support apparatus according to any one of claims 1-6. The calculation means according to any one of claims 1 to 7 , wherein the calculation means calculates the maximum torque based on the gear ratio and a vehicle speed, and calculates the required torque based on the vehicle speed and a running resistance. The driving support device according to item.

Images