JP2014211177A - Driving assistance apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve driving assistance for promoting energy-efficient driving.SOLUTION: A driving assistance apparatus is, for example, intended for a deceleration running period using fuel cut associated with acceleration off. First, a distance to a target position and a target vehicle speed which is a vehicle speed in the target position are recognized. A gear is then determined which provides the minimum fuel consumption until a vehicle reaches the target position at the target vehicle speed. If the determined gear is not a current gear, control is performed so that a driver is instructed to shift to the determined gear.

Description

  The present invention relates to a driving support device for encouraging a vehicle driver to drive with good fuel efficiency.

Japanese Patent Laid-Open No. 9-166209 JP 2012-219892 A

Conventionally, in order to improve vehicle fuel efficiency and reduce exhaust gas, a so-called fuel cut that stops fuel injection when the engine speed is equal to or higher than a predetermined fuel injection return speed in an accelerator-off state has been performed.
Patent Document 1 discloses a technique for downshift control of a shift stage so as to perform efficient fuel cut.
Patent Document 2 discloses a technique for instructing a downshift according to conditions such as an engine speed so that fuel cut can be continuously performed.

  By the way, in recent years, for example, a technology has been developed that recognizes the environment in front of a vehicle using an image captured by a stereo camera and supports driving according to various situations. The driving environment recognition process can recognize, for example, a red traffic light, a stop line, or a vehicle that has stopped at a red traffic light, an approach to a curve, etc. It is expected that fuel efficiency will be further improved through efficient operation.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to present to a driver a gear shift instruction for performing a fuel cut more appropriately when a target position to be stopped or decelerated is recognized. .

1stly, the driving assistance device which concerns on this invention recognizes the target vehicle speed which is the shift instruction | indication part which can show the upshift instruction | indication and downshift instruction | indication with respect to a driver | operator, the distance to a target position, and the vehicle speed in a target position. Of the current shift stage and the shift stage when upshifting or downshifting during deceleration driving by fuel cut, the fuel consumption amount until the target position is reached at the target vehicle speed. A shift speed determination unit that determines a shift speed at which the shift speed decreases, and a shift instruction to the determined shift speed when the shift speed determined by the shift speed determination unit is not the current shift speed A gear shift instruction control unit that performs control so as to be executed.
When it is recognized that the target position should be reached at the target vehicle speed, assuming that the vehicle is running with the accelerator off and fuel cut is performed, depending on the distance to the target position, the mileage can be increased by performing an upshift. It may be appropriate. Furthermore, not only can the travel distance be ensured by upshifting, but fuel can be cut as much as possible if appropriate downshifting is performed sequentially. For this reason, according to the distance to the target position and the target vehicle speed, a shift stage where the fuel consumption is reduced is determined between the current shift stage and the shift stage when upshifting or downshifting, and based on the determination result. An upshift instruction or a downshift instruction is executed.

  Secondly, in the driving support device according to the present invention described above, the shift speed determination unit can perform fuel cut until the target position is reached at the target vehicle speed as a shift speed at which fuel consumption is reduced. It is desirable to determine the shift speed at which the distance is maximum when the distance is less than or equal to the target position. The longer the fuel cut time, the lower the fuel consumption. Therefore, the driver is given a shift instruction that allows the fuel cut to be executed for a long time in the process of setting the target vehicle speed at the target position.

Thirdly, in the driving assistance apparatus according to the present invention described above, it is preferable that the shift speed determination unit performs a correction operation according to a gradient to the target position in calculating the distance at which the fuel can be cut.
The distance to the target position and the vehicle speed up to that point vary depending on the slope of the road on which the vehicle is traveling. That is, the time during which the fuel can be cut (not reaching the fuel injection return rotational speed) varies depending on the gradient. Therefore, the calculation of the distance at which the fuel can be cut includes a correction calculation according to the gradient to the target position.

Fourth, the driving support apparatus according to the present invention described above includes a learning processing unit that stores a shift time required for a gear shift operation by the driver, and the gear shift instruction control unit is stored in the learning processing unit. It is desirable to perform control so that a gear shift instruction to the determined gear position is executed when it is determined that the fuel injection return does not occur even if the gear shift of the shift time is performed.
Although the shift operation time differs for each individual driver, in the case of a driver that requires a relatively long time for the shift operation, it may be assumed that if the gear shift is performed as instructed, the fuel consumption is worsened. Therefore, when it is determined that the fuel injection return does not occur even if the learned gear shift is performed, a gear shift instruction is issued.

  According to the present invention, when the vehicle is running while the fuel cut is being executed with the accelerator off, a gear shift instruction can be presented to the driver to realize a more fuel-efficient driving, for example, a driving in which the fuel cut is performed for as long as possible. Can support good driving.

It is a block diagram of the vehicle control system of an embodiment of the invention. It is explanatory drawing of the distance to the stop position at the time of deceleration, and a vehicle speed. It is a flowchart of the process for the gear shift instruction | indication of embodiment. It is explanatory drawing of fuel cut distance calculation and gradient coefficient of embodiment. It is a flowchart and explanatory drawing of the learning process of embodiment. It is explanatory drawing of the table data updated by the learning process of embodiment.

  Embodiments of the present invention will be described below. In the embodiment, an MT (manual transmission) vehicle will be described as an example.

<1. Vehicle system configuration>
FIG. 1 shows a configuration of a vehicle control system 1 including a driving support apparatus as an embodiment according to the present invention. In FIG. 1, only the configuration of the main part according to the present invention is extracted and shown from the configuration of the vehicle control system 1.
The vehicle control system 1 includes an imaging unit 2A, 2B, an image processing unit 3, a memory unit 4, a driving support control unit 5, a display control unit 6, an engine control unit 7, a brake control unit 8, a sensor / operator 10 and a display. Part 11, engine-related actuator 12, brake-related actuator 13, and bus 15.

In the vehicle control system 1, an object or the like existing in front of the vehicle is recognized, and driving support control can be performed according to the recognized result.
In order to recognize the environment outside the vehicle, the imaging units 2A and 2B are installed so as to be able to image the traveling direction (front) in the vehicle. In particular, two cameras as the imaging units 2A and 2B are installed so as to enable distance measurement by a so-called stereo method, and the two image data captured by the imaging units 2A and 2B, respectively. (Referred to as first captured image data and second captured image data) are output for each frame.

The image processing unit 3 includes a semiconductor integrated circuit including a CPU (Central Processing Unit) or DSP (Digital Signal Processor), a ROM (Read Only Memory), a RAM (Random Access Memory) as a work area, and a nonvolatile memory, for example. Then, various processes according to programs stored in the ROM are executed.
The image processing unit 3 stores each frame image data as the first captured image data and the second captured image data supplied from the imaging units 2 </ b> A and 2 </ b> B in the memory unit 4. Based on the first captured image data and the second captured image data of each frame, various processes for recognizing an object or the like existing in front of the vehicle as an external environment are executed.
Although various types of object recognition and vehicle control corresponding thereto are various, in the present embodiment, particularly, a red signal, a stop line, a front stop vehicle, an approach point on a curved road, and the like are detected. That is, image processing is performed to detect a position to be stopped or a position to be decelerated to a certain speed as a target position.

Specifically, the image processing unit 3 executes distance image generation processing for generating a distance image based on the first captured image data and the second captured image data held in the memory unit 4. A distance image is a pattern matching that detects corresponding points between a pair of image data that have been captured in stereo, finds the shift in coordinates between the detected corresponding points as a parallax, and uses the parallax to implement the principle of triangulation. This is data representing the distance to the corresponding point in space on the image.
Next, an area selection process based on the distance image generated by the distance image generation process is executed, and an object detection process for detecting an object existing in the image with respect to the distance image is executed using the result of the area selection process. For example, a traffic light, a stop line, a stopped vehicle, or the like is detected as an object to be the above-described target position. With such image processing, information on the presence / absence of the target position and the distance to the target position can be obtained.

The driving support control unit 5 is composed of, for example, a microcomputer including a CPU, ROM, RAM, nonvolatile memory, and the like, and results of image processing by the image processing unit 3 and detection information and operations obtained by the sensors / operators 10. Various control processes for driving support are executed based on the input information and the like.
The driving support control unit 5 is connected to the display control unit 6, the engine control unit 7, and the brake control unit 8, which are also configured by a microcomputer, via the bus 15, and performs data communication with each of these units. It is possible to do.
Further, information related to object recognition from the image processing unit 3 and sensor signals such as an accelerator opening sensor, a vehicle speed sensor, and a brake switch in the sensor / operator 10 are input to the driving support control unit 5. Based on these inputs, various driving assistance, for example, control for assisting the driver, such as collision avoidance and auto cruise, is performed.
In the description of the present embodiment, the driving support control by the driving support control unit 5 will be described by paying attention to a gear shift instruction to the driver for realizing low fuel consumption particularly during driving in the fuel cut state. Go.

The sensors / operators 10 comprehensively represent various sensors and operators provided in the host vehicle. In the figure, as a sensor related to the operation of the present embodiment, a vehicle speed sensor 10A, an engine speed sensor 10B, an accelerator opening sensor 10C that detects the accelerator opening from the amount of depression of the accelerator pedal, and a clutch that detects the stroke of the clutch pedal. Stroke sensor 10D, brake switch 10E that is turned on / off according to the operation of the brake pedal, shift position sensor 10F that detects the shift position by operating the shift lever, and G sensors (acceleration in the front, rear, left, and right, for example) Sensor) unit 10G is shown. Other than these, for example, an intake air amount sensor that detects an intake air amount, a throttle opening sensor that detects the opening of a throttle valve that is interposed in the intake passage and adjusts the intake air amount that is supplied to each cylinder of the engine, There are a water temperature sensor for detecting a cooling water temperature indicating an engine temperature, an outside air temperature sensor for detecting an air temperature outside the vehicle, and the like.
Further, as an operator, an ignition switch for instructing start / stop of the engine, a shift lever, a display changeover switch for switching display information in an MFD (Multi Function Display) provided in the display unit 11, etc. There is.

The display unit 11 comprehensively represents various meters such as a speedometer and a tachometer provided in a meter panel installed in front of the driver, an MFD, and other display devices for presenting information to the driver. Various information such as the total travel distance of the host vehicle, the outside air temperature, and instantaneous fuel consumption can be displayed on the MFD simultaneously or by switching.
A gear shift indicator 30 is also provided as a combination meter together with various meters. The gear shift indicator 30 includes a shift speed display section 31 that presents the current shift speed (and neutral) by a plurality of display segments, an upshift instruction section 32 that instructs the driver to upshift, and a downshift to the driver. Has a downshift instructing unit 33. The gear shift indicator 30 may be realized on the display in the MFD.

  The display control unit 6 controls the display operation by the display unit 11 based on a detection signal from a predetermined sensor in the sensor / operation unit 10, operation input information by the operation unit, and further an instruction from the driving support control unit 5. To do. In particular, the display control unit 6 in the present embodiment performs display control of the gear position display unit 31 based on information from the shift position sensor 10F. In addition, the display control unit 6 performs display control of the upshift instruction unit 32 or the downshift instruction unit 33 in response to a request for an upshift instruction display from the driving support control unit 5 or a request for a downshift instruction display.

The engine control unit 7 controls various actuators provided as the engine-related actuator 12 based on a detection signal from a predetermined sensor in the sensor / operator 10 or operation input information by the operator. As the engine-related actuator 12, for example, various actuators related to engine driving such as a throttle actuator that drives a throttle valve and an injector that performs fuel injection are provided.
For example, the engine control unit 7 performs engine start / stop control according to the operation of the ignition switch described above. The engine control unit 7 also controls the fuel injection timing, the fuel injection pulse width, the throttle opening, and the like based on detection signals from predetermined sensors such as an engine speed sensor and an accelerator opening sensor. In particular, the engine control unit 7 performs fuel cut control when conditions such as the accelerator off state, the engine speed being equal to or higher than a predetermined speed, and the shift position being not neutral are satisfied. Further, during the fuel cut, if the engine speed becomes equal to or lower than the predetermined fuel return speed, control is performed to return the fuel injection.

The brake control unit 8 controls various actuators provided as the brake-related actuator 13 based on a detection signal from a predetermined sensor in the sensor / operator 10 or operation input information by the operator. As the brake-related actuator 13, for example, various brake-related actuators such as a hydraulic pressure control actuator for controlling the hydraulic pressure output from the brake booster to the master cylinder and the hydraulic pressure in the brake fluid piping are provided.
For example, the brake control unit 8 controls the above hydraulic pressure control actuator to brake the host vehicle when an instruction to turn on the brake is issued from the driving support control unit 5. The brake control unit 8 calculates the slip ratio of the wheel from detection information of a predetermined sensor (for example, an axle rotation speed sensor or a vehicle speed sensor), and increases or decreases the hydraulic pressure by the hydraulic control actuator according to the slip ratio. By so doing, so-called ABS (Antilock Brake System) control is realized.

  In the case of the present embodiment, as one of the driving support controls by the driving support control unit 5, driving in a fuel cut state is performed in order to travel with better fuel consumption and reach the target position at the target vehicle speed. The gear shift is instructed to the person. Therefore, the driving support control unit 5 realizes functions as a target recognition unit 5a, a gear position determination unit 5b, a gear shift instruction control unit 5c, and a learning processing unit 5d shown in the figure by processing according to a program stored in the internal ROM. To do.

  The target recognition unit 5a recognizes the distance to the target position and the target vehicle speed that is the vehicle speed at the target position. The target position is a position determined by, for example, a red signal or a stop line recognized by the image processing unit 3, a vehicle that stops at a red signal ahead, or a road curve entry point. When the target position is a position to be stopped, the target vehicle speed is 0 km / h. If the target position is not a position to be stopped at a curve entry point or the like, a target vehicle speed suitable for each is calculated.

The shift speed determination unit 5b determines the fuel consumption before reaching the target position at the target vehicle speed, among the current shift speed and the shift speed when upshifting or downshifting, during deceleration traveling by fuel cut. The gear position at which is reduced is determined. Specifically, fuel consumption is the case when traveling at the current gear stage, when traveling at the upshifted gear stage, when traveling at the current gear stage, and when traveling at the downshifted gear stage. Judge whether or not will decrease. More specifically, it is determined in any of the above cases where the speed at which the fuel can be cut is equal to or less than the distance to the target position before reaching the target position at the target vehicle speed.
The gear position determination unit 5b also performs a correction calculation according to the gradient to the target position in calculating the distance at which the fuel can be cut.

  The gear shift instruction control unit 5c executes a shift instruction to the determined shift stage on the display unit 11 (gear shift indicator 30) when the shift stage determined by the shift stage determination unit 5b is not the current shift stage. To control. That is, if it is determined that it is better to upshift, a request for upshift instruction display is output to the display control unit 6 and the display of the upshift instruction unit 32 is executed. If it is determined that it is better to downshift, a request for downshift instruction display is output to the display control unit 6 and the display of the downshift instruction unit 33 is executed. When the gear position determination unit 5b determines that the current gear position is appropriate, the gear shift instruction control unit 5c does not particularly need to make a display request to the display control unit 6.

  The learning processing unit 5d performs learning processing for storing a shift time required for the gear shift operation by the driver. For example, when the driver performs a gear shift operation, the learning value is updated using the required time. The learning value is referred to by the gear shift instruction control unit 5c, and the gear shift instruction control unit 5c determines that the fuel injection return does not occur even when the gear shift of the shift time (learning value) stored in the learning processing unit 5d is performed. In this case, the gear shift instruction to the gear determined by the gear determination unit 5b is executed.

<2. Explanation of gear shift instruction during deceleration>
The concept of the gear shift instruction of the present embodiment for realizing the low fuel consumption driving at the time of deceleration will be described. An example in which 1st to 6th speeds are provided as the shift speed is used.
FIG. 2 shows, for each gear position, the relationship between the vehicle speed and distance during deceleration from the state of traveling at 50 km / h until the vehicle stops, for example. This indicates the difference in travel distance in the accelerator-off state at each shift stage. Straight lines G1 to G6 indicate the cases of the first to sixth speeds of the shift stage. As shown in the figure, the slopes of the straight lines G1 to G6 vary depending on the gear position. The traveling distance increases as the vehicle decelerates at a high shift position such as 6th gear. On the other hand, the lower the gear speed, such as the second speed or the first speed (the gear speed with the larger gear ratio), the greater the engine brake is applied and the traveling distance becomes shorter. The distances to the stop position reached by running at the first to sixth gears are dA to dF.

Dotted lines F1 to F6 are vehicle speeds (fuel injection return points) corresponding to the fuel injection return speeds at the first to sixth gears. The intersection of a straight line with the same number and a dotted line (for example, the straight line G1 and the dotted line F1) is the fuel injection return point.
As described above, the engine control unit 8 performs fuel cut control if the accelerator is off and the engine speed is equal to or greater than the predetermined rotational speed and is not in the neutral position. In FIG. 2, it is assumed that the accelerator is turned off from the state of 50 km / h and the fuel is cut. Assuming that the vehicle is traveling at the first speed, the fuel cut is terminated when the intersection of the straight line G1 and the dotted line F1 is reached, and the fuel injection is resumed.

In the example of FIG. 2, the effectiveness of the gear shift during the fuel cut will be described.
For example, it is assumed that the vehicle is traveling at 50 km / h at the second speed and the distance to the target stop position is dB ′. If the vehicle travels in the second speed, it is expected to reach the position of the distance dB over the distance dB ′, but the fuel injection is returned at the intersection of the straight line G2 and the dotted line F2. However, in this case, the point of the distance dB ′ can be reached even if downshifting to the first speed. Therefore, by downshifting to the first speed (straight line G1 ′) before returning to fuel injection at the second speed, the fuel injection return can be delayed until the intersection of the straight line G1 ′ and the dotted line F1 ′, and the fuel cut time can be extended. it can.
For example, it is assumed that the vehicle travels at 50 km / h in the second speed and the distance to the target stop position is dC ′. In this case, since it can only reach the position of the distance dB with the second speed, it is better to upshift to the third speed. If the vehicle travels in the state of the straight line G3, it is scheduled to reach the position of the distance dC over the distance dC ′, but if it is left as it is, the fuel injection is returned early at the intersection of the straight line G3 and the dotted line F3. Therefore, downshift to the second speed (straight line G2 ′). In this case, the fuel injection returns at the intersection of the straight line G2 ′ and the dotted line F2 ′, but the point of the distance dC ′ can be reached even if it is further downshifted to the first speed. Therefore, the speed is further downshifted to the first speed before returning to the fuel injection at the second speed, and the fuel injection return is delayed until the timing of the intersection of the straight line G1 ″ and the dotted line F1 ″.
As in the above example, when decelerating by fuel cut, select a gear position that reduces fuel consumption in the process of reaching the target position at the target vehicle speed, that is, a gear position that can delay the return of fuel injection as much as possible. If it is made, driving | running | working with high fuel consumption is attained.
In the present embodiment, a gear shift instruction is given by the gear shift indicator 30 in order to prompt the driving vehicle to perform such driving.

<3. Example of processing for gear shift instruction>
A specific example of a process for instructing a gear shift during deceleration traveling by fuel cut will be described.
FIG. 3 shows processing of the driving support control unit 5 for display control of the upshift instruction unit 32 and the downshift instruction unit 33 of the gear shift indicator 30. FIG. 3 shows an example of processing executed by the functions of the target recognition unit 5a, the gear position determination unit 5b, and the gear shift instruction control unit 5d as control processing when the accelerator is off. In particular, Steps S101 and S110 are processing by the function of the target recognition unit 5a, Steps S102 to S107, S109, S111 to S115, and S117 are processing by the gear position determination unit 5b, and Steps S108 and S116 are processing by the function of the gear shift instruction control unit 5d.

The driving support control unit 5 repeatedly executes the process of FIG. The process of FIG. 3 includes an upshift instruction process (S101 to S109) and a downshift instruction process (S110 to S117).
During the accelerator-on period, the driving support control unit 5 ends the process of FIG. 3 from step S100. For example, when accelerator-off is recognized by the detection information of the accelerator opening sensor 10B, the process proceeds from step S100 to S101.

In step S101, the driving support control unit 5 recognizes the distance and gradient to the target position, and the target vehicle speed at the target position. For example, it is determined whether there is a red signal or a stop line as a target position to be stopped based on the information on the object in front obtained by the image processing unit 3, and if there is, information on the distance to the target position Is acquired from the image processing unit 3. When the target position is the stop position, the target vehicle speed is set to 0 km / h. If the target position is not a stop position such as an entry point on a curved road, a safe speed at that position is obtained and set as the target vehicle speed.
The target vehicle speed at the curve entry point can be obtained, for example, as follows. When there is a curve with a radius r (m) ahead of the host vehicle traveling on a straight road, the curve entry allowable speed Vc can be obtained by Vc = √ (y0 · r). However, y0 is the allowable lateral acceleration on the curve. The curve entry allowable speed Vc thus obtained may be set as the target vehicle speed. The curve radius r can be calculated by, for example, obtaining the curvature of the lane recognized by the image processing unit 3 from the captured image.

When the target position is not detected in the above step S101, the process of FIG. 3 is completed from step S101, and the process is performed again from step S100.
When the target position, the target vehicle speed, and the gradient are recognized in step S101, the driving support control unit 5 performs a rapid deceleration determination in step S102. This is a process of confirming whether or not the driver's vehicle has suddenly stepped on the brake based on the detection information of the brake switch 10E and the G sensor 10G. The case where the brake is stepped on suddenly is a case where sudden stop or deceleration is performed for safety for some reason. If it is determined that such a sudden deceleration, gear shift instruction control is not appropriate for the subsequent operation, and the process of FIG. 3 is exited from step S102.

If it is not determined that the vehicle is suddenly decelerated, the driving support control unit 5 proceeds to step S103, and determines whether the current speed is below the target vehicle speed before the target. As shown in FIG. 2, the travel distance in the accelerator-off state at each gear position can be calculated using the current vehicle speed and the values of the slopes of the straight lines G1 to G6.
When the target vehicle speed is below the target vehicle speed, it is appropriate to perform an upshift (see the example of the target position dC ′ in FIG. 2). On the other hand, if the current vehicle speed does not fall below the target vehicle speed before the target, an upshift is not necessary (see the example of the target position dB ′ in FIG. 2). Move on.

  First, a case where it is determined that the vehicle speed is lower than the target vehicle speed before the target, that is, a case where an upshift is assumed will be described. In this case, the driving support control unit 5 proceeds from step S103 to step S104, and checks whether or not there is a shift stage that is one higher than the current shift stage. For example, in the case of a 1st to 6th transmission, if the current speed is 6th, an upshift is not possible. As described above, if there is no shift position one level higher, the process proceeds to a process for a downshift instruction after step S110.

If there is a gear that is one higher, the driving support control unit 5 confirms in step S105 whether or not the engine speed at the upshift destination gear is equal to or higher than the fuel injection return speed + α. To do. Since the accelerator is off, the engine speed decreases if an upshift is performed. If the engine speed becomes equal to or lower than the fuel injection return speed when the upshift is performed and the fuel injection returns, the fuel efficiency effect by the upshift instruction cannot be obtained. In other words, it is not appropriate to upshift at this time unless at least the situation where the upshift is performed does not reach the fuel injection return rotational speed.
Therefore, it is determined whether the engine speed after the upshift is equal to or higher than the speed obtained by adding a margin of + α to the fuel injection return speed, and even if the upshift is performed, the fuel injection return speed is not reached. Confirm that the situation is correct. As the value of + α, the number of revolutions is set so that the fuel cut can be continued to some extent after the upshift.
If it is determined in step S105 that the rotational speed is not equal to or higher than the fuel injection return rotational speed + α, it is determined that there is no opportunity to give an upshift instruction, and the process proceeds to a process for downshift instruction in step S110 and subsequent steps.

  If it is determined in step S105 that the engine speed after the upshift is equal to or greater than the fuel injection return speed + α, is the driving support control unit 5 in step S106, is it better to improve the fuel consumption by upshifting to the target position? Alternatively, it is determined whether the fuel consumption is better if the current shift position is kept. That is, at present, it is determined which of the upshift and the shift keep can cut the fuel by a long distance. A specific example will be described with reference to FIG.

  FIG. 4A is table data (hereinafter referred to as “fuel cut distance table”) that stores the current vehicle speed and the value of the distance [km] at which fuel cut is possible at each gear position. The driving support control unit 5 stores such a fuel cut distance table in an internal ROM, a non-volatile memory or the like, and performs the process of step S106 with reference to this. It should be noted that the distance value is merely an illustrative example, and in reality, it is desirable to set the vehicle speed classification more finely than the 10 km / h classification.

This fuel cut distance table is used to compare the upshift case with the shift keep case.
It is assumed that the current vehicle speed is 50 km / h, the shift position is the second speed, and the distance to the target position is 0.25 km.
Since the vehicle speed is 50 km / h in the second speed, the distance at which fuel can be cut in this state (shift keep) is 0.16 km from the fuel cut distance table. However, the subsequent downshift is also considered. For example, when the vehicle speed reaches 20 km / h, the distance that can be cut by the downshift to the first speed is 0.16-0.03 + 0.04 = 0.17 km. In other words, 0.17 km of fuel can be cut during the travel of 0.25 km to the target position.
Next, the case of upshift is obtained. When upshifting to 3rd speed, the fuel cut distance will be 0.19km, but then when the vehicle speed reaches 30km / h, downshift to 2nd speed and when the vehicle speed further reaches 20km / h A downshift to the first speed is also assumed. Then, the distance at which the fuel can be cut is 0.19−0.05 + 0.07−0.03 + 0.04 = 0.22 km. In other words, during the travel of 0.25 km to the target position, the fuel can be cut by 0.22 km.
Therefore, in such a case, it is determined that it is better to upshift before reaching the target position.

On the other hand, for example, it is assumed that the current vehicle speed is 40 km / h, the shift position is the second speed, and the distance to the target position is 0.14 km. Similarly to the above, taking into account the subsequent downshift, the fuel cut distance in the case of shift keep and upshift is obtained.
In the case of the shift keep, it is assumed that the vehicle is downshifted to the first gear when the vehicle speed becomes 20 km / h. Then, the distance at which the fuel can be cut is 0.12-0.03 + 0.04 = 0.13 km. In other words, 0.13 km of fuel can be cut during 0.14 km travel to the target position.
In the case of an upshift, it is assumed that when the vehicle speed reaches 30 km / h, the vehicle shifts down to the second gear, and when the vehicle speed reaches 20 km / h, the vehicle shifts down to the first gear. Then, the distance at which the fuel can be cut is 0.12-0.05 + 0.07-0.03 + 0.04 = 0.15 km. In this case, the distance at which the fuel can be cut exceeds the distance to the target position.
In such a case, it is determined that it is better to keep the current gear position.
The above example is an example in which the target vehicle speed at the target position is set to 0 km / h. However, when the target vehicle speed is set to, for example, 20 km / h at a curve entry point or the like, 20 km / h in the fuel cut distance table. It may be calculated using the value of the fuel cut distance up to the target vehicle speed, such as the values up to.

For example, as described above, the distance at which the fuel cut can be performed in the case of the shift keep and the upshift is obtained, and the one having the maximum fuel cut distance below the distance to the target position is selected.
However, the distance value in the fuel cut distance table of FIG. 4A is a value on a flat road. When there is a slope, the running resistance is added to the vehicle, and the distance at which fuel can be cut changes. Accordingly, the above calculation is performed by multiplying the coefficient K in FIG. 4B by the fuel cut distance in FIG. 4A according to the detected gradient.
This will be described with reference to the model of FIG. 4C. The vertical axis indicates the height position of the road. It is assumed that the up to the target position is an uphill, the slope of the section shown as the distance X1 is α1, and the slope of the section shown as the distance X2 is α2. For example, the driving support control unit 5 detects the current gradient based on the information from the G sensor 10G, and uses the information from the image processing unit 3 to detect the horizontal distance X to the target position, and the gradient and horizontal distance (α1, X1 to the target position). ) (Α2, X2) is detected. The distance to the target position is X1 / cos α1 + X2 / cos α2.
In this case, in the section of the distance X1, the coefficient K corresponding to the gradient α1 is multiplied by the value in the fuel cut distance table in FIG. 4A. In the section of the distance X1, the coefficient K corresponding to the gradient α2 is multiplied by the value in the fuel cut distance table. Then, the calculation for comparing the fuel cut distance is performed.
By doing in this way, it is possible to determine which of the shift keep and the upshift is advantageous in terms of fuel efficiency in consideration of the gradient situation.

In step S106 of FIG. 3, it is determined whether or not to upshift by the above-described method, for example. When it is determined that the shift keep is appropriate, the process proceeds to step S110. However, when it is determined that the upshift is appropriate, the process proceeds to step S107, and the driving support control unit 5 refers to the learning value of the shift time, and learns the learning value. Judge whether there is enough time in minutes. This process prevents the fuel injection from returning during the shift when an upshift instruction is issued, and the shift time (shift from the start of the shift according to the operation of the shift lever and clutch pedal of the driving vehicle). This means that the time until completion is different for each driver.
The upshift instruction is not appropriate when there is a possibility that the fuel injection return speed may be reached during the shift and the fuel injection returns. In particular, the degree of decrease in engine speed increases during the neutral state during shifting. However, since the shift time is different for each individual, it is preferable to change how much time is required according to the driver. Therefore, the driver's shift time is learned as will be described later, and it is determined whether or not there is enough time to not return to fuel injection even if the current driver performs an upshift. That is, the learning value of the shift time may be compared with the time required to reach the fuel injection return rotational speed during the upshift. The time required to reach the fuel injection return rotational speed can be calculated from the current vehicle speed, the engine rotational speed, the shift speed after the shift, the rotational speed decrease speed in the neutral state, and the like.

If it is determined in step S107 that there is a time margin, the process proceeds to step S108, and upshift instruction control is performed. That is, the driving support control unit 5 outputs a request for upshift instruction presentation to the display control unit 6.
If there is no time margin, the process proceeds to step S110 without performing the process of step S108. That is, the execution control of the upshift instruction display is not performed.

When the upshift instruction control is performed in step S108, the driving support control unit 5 confirms whether or not the neutral range or the clutch is disengaged in step S109. For example, the detection signals of the clutch stroke sensor 10D and the shift position sensor 10F are confirmed. When the neutral range or the clutch is disengaged, it is possible that the driver is traveling in the neutral state during the shift operation. Then, it returns to step S105 and repeats a process. In some cases, the upshift instruction display is terminated (does not proceed to step S108) in accordance with the determination in steps S105, S106, and S107.
In step S109, it is determined that neither the neutral range nor the clutch is disengaged is a situation where the driver has completed the upshift according to the instruction. In that case, the process returns to step S101, and the same processing as described above is performed again from that state.

Here, the learning process will be described. FIG. 5A shows a learning process executed by the driving support control unit 5 using the function of the learning processing unit 5d. The driving support control unit 5 executes the learning process of FIG. 5A in parallel with the process of FIG. 3 while the vehicle is traveling.
In step S200, the driving support control unit 5 confirms whether or not the learning of the shift time has been completed. If completed, the process proceeds to step S208, and if not completed, the process proceeds to step S201. If the learning has not been completed and the process proceeds to step S201, it is confirmed whether or not a gear shift has been performed. When a gear shift is performed, it becomes a learning timing.
Although not shown in FIG. 5, the driving support control unit 5 monitors detection signals of the shift position sensor 10F and the clutch stroke sensor 10D, and performs time measurement from the start of the shift using an internal timer. ing. For example, time measurement is started from the timing when the clutch is depressed, and time measurement is ended at the timing when the shift is completed by the shift position sensor 10F. Thereby, the shift time can be measured.

  If it is detected that the gear shift has been performed, the driving support control unit 5 confirms whether or not the fuel injection return has occurred during the gear shift by communication with the engine control unit 7 in step S202. If fuel injection return has not occurred during the gear shift, the learning value is updated in step S204.

FIG. 6 shows an example of a learning data table in which the driving support control unit 5 stores learning data.
For example, as the learning data table, an upshift table group and a downshift table group are used as shown in FIG. 6A. The upshift table group has upshift tables corresponding to upshifts of 1st speed → 2nd speed, 2nd speed → 3rd speed,... 5th speed → 6th speed. Similarly, the downshift table group includes downshift tables corresponding to downshifts of 2nd speed → 1st speed, 3rd speed → 2nd speed,... 6th speed → 5th speed.
Each of these 10 tables has a structure in which learning values Vs (Vs0-1... Vs18-7) are stored in accordance with the engine speed (rotation speed before shifting) and the vehicle speed, as shown in FIG. 6B, for example. Is done. In the initial state, initial values are stored as learning values Vs (Vs0-1... Vs18-7). Generally, the faster the vehicle speed and the higher the engine speed, the shorter the shift time. Therefore, for example, initial values such as learning value Vs0-1 = 0.6 seconds and learning value Vs18-7 = 0.4 seconds are set.

  Now, for example, it is assumed that the driver upshifts from the first speed to the second speed at a vehicle speed of 20 km / h and an engine speed of 2000 rpm. If the process proceeds to step S204 in this situation, the learning value Vs2-2 is updated in the first-speed → second-speed upshift table in the upshift table group.

In the learning value update processing in step S204, first, the coefficient ka is multiplied by the shift time ta measured at the time of the current gear shift. Since the fuel injection has not been returned, the coefficient ka is a coefficient value that shortens the measurement time somewhat. And the average value with the learning value Vs memorize | stored at that time is calculated | required, and the said average value is memorize | stored as a new learning value. That is,
Vs ← (ta · ka + Vs) / 2
And For example, in the case of the above example, the learning value Vs2-2 is updated in this way.

  On the other hand, fuel injection return may occur during the shift. In that case, the process proceeds from step S202 to S203, and it is confirmed whether or not the gear shift is completed within a predetermined time. For example, when the driver continues to travel in the neutral range for a long time and then connects to a certain gear position, the measured value of the shift time should not be used for the learning process. Therefore, in order not to reflect such a shift time value in the learning process, when it is determined in step S203 that the shift time value is not completed within a predetermined time assumed as a normal gear shift, the process returns to step S200. That is, the learning value is not updated.

If the gear shift is completed within a predetermined time, the learning value is updated in step S205. In this case, the value is updated to a value that does not cause fuel injection return. Specifically, the coefficient kb is multiplied by the time obtained by subtracting the time from the start of gear shift to the return of fuel injection from the shift time from the start of gear shift to the completion, and this is added to the learned value so far.
This will be described with reference to FIG. 5B. The vertical axis represents engine speed, and the horizontal axis represents time. It is assumed that the gear shift is started at time T0, the fuel injection return occurs at time T1, and then the gear shift is completed at time T2. ta is the shift time, tb is the time from the start of shifting to the fuel injection return, and tc is the time from the fuel injection return to the shift completion. In this case, the learning value Vs is
Vs ← (ta−tb) · kb + Vs
And The timing for measuring the time tb may be received from the engine control unit 7.
(Ta-tb) in the formula is the time tc. This corresponds to an extra time when the fuel recovery is not completed in time for the learning value used in step S107 of FIG. Therefore, the extra time is multiplied by a coefficient kb for adding a time margin, and the update is performed by adding it to the learning value Vs so far. The updated learning value Vs is a shift time value for the driver to complete the gear shift without causing the fuel injection return.

As described above, while the learning value Vs (Vs0-1... Vs18-7) in the upshift table group and the downshift table group is updated in step S204 or S205, the learning value Vs is updated in step S107 in FIG. (And step S115 described later). If the learned value Vs referred to in step S107 is appropriate, the fuel injection return usually does not occur if the driver normally performs a shift operation.
Therefore, in step S206 in FIG. 5, it is confirmed whether or not the shift operation is completed without the fuel injection returning continuously for a predetermined number of times. If applicable, the learning value Vs at that time is appropriate, and learning is completed in step S207.
During a period in which the condition of step S206 is not satisfied, the process proceeds to step S208.
Further, even after it is determined in step S207 that learning is completed, the process in FIG. 5 proceeds from step S200 to step S208, and it is confirmed whether or not learning is necessary again.
In step S208, it is confirmed whether fuel injection return has occurred during the shift continuously for a predetermined number of times or more. If this is the case, the learning value Vs at that time is not appropriate, so that learning is not completed in step S209. That is, after the learning process is started, when learning is not yet sufficiently performed, or when learning is once completed but learning should be performed again, learning is not completed in step S209. The process proceeds from step S200 to S201. Thus, for example, when the driver changes, relearning is performed, and learning corresponding to the driver situation at that time is performed.

  The shift time of the current driver is learned by the learning process as described above, and the upshift instruction reflecting the time during which the driver does not perform the fuel injection return in steps S107 and S108 in FIG. Control can be performed.

In the learning data table configuration described with reference to FIGS. 6A and 6B, the learning value Vs is stored in detail according to the type of up / down shift (shift direction), the gear position, and the current vehicle speed / engine speed. It was supposed to be. Since the shift time differs somewhat depending on these factors, storing the learning value Vs in detail is preferable in terms of obtaining the accurate learning value Vs. In this case, in step S107 of FIG. 3, it goes without saying that the learning value Vs is selected and referred to based on the gear stage to be shifted, the current engine speed, and the vehicle speed.
However, other learning data table configurations are possible. For example, each of the ten tables in FIG. 6A may be configured to store learning values Vs (Vs0 to Vs180) corresponding to the vehicle speed as shown in FIG. 6C, or learning values corresponding to the engine speed as shown in FIG. 6D. It is good also as a structure which memorize | stores Vs (Vs1000-Vs7000). Furthermore, as shown in FIG. 6E, a configuration in which only one learning value Vs is stored, that is, a configuration in which only the shift direction and the shift speed are distinguished may be employed.

In addition, there is an example in which one upshift table and one downshift table are provided as shown in FIG. The upshift table and the downshift table are structured as shown in FIGS. 6B, 6C, 6D, or 6E.
Further, there is an example in which one shift table is provided as shown in FIG. The shift table has a structure as shown in FIG. 6B, FIG. 6C, FIG. 6D, or FIG.
As described above, there are various learning data table structures, and the learning data table structure may be determined according to the processing load, the memory capacity, the request for the precision of the learning value, the required learning completion time, and the like. As a matter of course, the finer the learning value Vs, the more precise control operation becomes possible. However, in order to reduce the processing load, memory capacity, and shorten the learning completion time, it is better not to subdivide the learning value Vs too much.

Returning to FIG. 3, processing related to the downshift instruction after step S <b> 110 will be described.
In step S110, the driving support control unit 5 recognizes the distance to the target position, the gradient, and the target vehicle speed at the target position, as in step S101. When the target position, the target vehicle speed, and the gradient are recognized in step S110, the driving support control unit 5 performs a rapid deceleration determination in step S111 as in step S102. If it is not determined that the vehicle is suddenly decelerated, the driving support control unit 5 proceeds to step S112, and checks whether there is a gear position that is one lower than the current gear position. That is, it is determined whether a downshift is possible. Note that if the target position is not recognized in step S110, if it is determined that there is a sudden deceleration in step S111, or if it is determined in step S112 that there is no next lower gear, the process of FIG.

In step S113, it is confirmed whether or not the engine speed at the current shift speed has reached the speed of fuel injection return speed + β. This is to determine whether or not the engine speed has decreased at the current shift stage and the fuel injection recovery is almost in a state of return. The β value is set to an appropriate value according to this purpose.
A downshift instruction is not yet required unless the fuel injection return rotational speed + β has reached the rotational speed. If the fuel injection return rotational speed + β has reached the rotational speed, in step S114, it is determined whether it is better to downshift before reaching the target position, or it is better to keep the current shift position. judge. That is, at present, it is determined which of the downshift and the shift keep can cut the fuel by a long distance. The determination method is the same as the example described in FIG. 4, and the distance that can be cut by fuel in the case of shift keeping and in the case of downshift is the maximum that is less than the distance to the target position, reflecting the slope. Should be selected.

If it is determined that the shift keep is appropriate, the process in FIG. 3 is terminated, and the process returns to step S100. When it is determined that the downshift is appropriate, the process proceeds to step S115, and the driving support control unit 5 refers to the learning value Vs of the shift time stored in the learning data table described above, and there is a time margin for the learning value. It is determined whether or not there is. This is the same processing as in step S107. If it is determined that there is enough time, the process proceeds to step S116, and downshift instruction control is performed. That is, the driving support control unit 5 outputs a request for downshift instruction presentation to the display control unit 6.
If there is no time margin, the process of FIG. 3 is terminated without performing the process of step S116. That is, the execution control of the downshift instruction display is not performed.

When the downshift instruction control is performed in step S116, the driving support control unit 5 confirms in step S117 whether the neutral range or the clutch is disengaged as in step S109. If the neutral range or the clutch is disengaged, the process returns to step S113 and the process is repeated. In some cases, the downshift instruction display may be terminated (does not proceed to step S116) in accordance with the determinations in steps S113 and S114.
In step S117, it is determined that neither the neutral range nor the clutch is disengaged is a situation where the driver has completed the downshift according to the instruction. In that case, the process returns to step S101.

<4. Summary and Modification>
As described above, in the present embodiment, when it is recognized that the target position should be reached at the target vehicle speed while traveling with the accelerator off and performing fuel cut, the vehicle travels as long as possible in the fuel cut state. An upshift or downshift instruction is provided so that it is possible. That is, when the process of FIG. 3 is repeated during the fuel cut operation, the appropriateness of the upshift or the downshift is always determined according to the driving situation, and the upshift or the downshift is more advantageous for fuel consumption driving. An upshift instruction or a downshift instruction is performed. As a result, it is possible to provide driving assistance that prompts the driver to drive with good fuel consumption before reaching a stop position such as a red light or a deceleration position such as a curve entry point. In addition, it can respond to the changing driving conditions.
Whether or not it is better to upshift or downshift is determined by a process of determining a gear position that maximizes the distance at which the fuel cut can be performed at or below the distance to the target position. As a result, it is possible to give an instruction to the driver to efficiently execute the fuel cut by simple and direct determination processing without performing complicated fuel consumption calculation or the like.
In addition, the driving support control unit 5 performs correction calculation according to the gradient to the target position in calculating the distance at which the fuel can be cut. This makes it possible to make an appropriate determination according to the gradient and improve the appropriateness of the shift instruction.

  Further, the driving support control unit 5 performs a learning process in which the driver stores a shift time required for the gear shift operation, and refers to the learning value Vs to determine that the fuel injection return does not occur even if the gear shift is performed. Then, a gear shift instruction (up / down shift instruction) to the determined gear position is controlled. Thereby, an appropriate shift instruction corresponding to each driver is realized.

The configuration and processing of the present invention are not limited to the above embodiment.
In the embodiment, the example in which the learning process is added has been described. However, the learning process is not performed, and the setting value may be referred to instead of the learning value Vs in steps S107 and S115 in FIG.
Further, it is conceivable that the processing of FIG. 3 is limited to only the processing for upshift instruction control in steps S100 to S109, or only the processing for downshift instruction control in steps S100 and S110 to S117.
The configuration example of FIG. 1 is an example. Various configurations of each control unit and devices mounted as sensors / operators can be considered. For example, the image processing unit 3 and the driving support control unit 5 may be integrated.
Further, the gear shift indicator 30 in the display unit 11 has been described as an example of a shift instruction unit that can present an upshift instruction and a downshift instruction to the driver. However, for example, a configuration may be used in which a shift instruction is given to the driver by voice.

  In addition, as described in the example of the MT vehicle, the up / downshift at the time of traveling in the manual transmission mode is also applied to the vehicle having the manual transmission mode in the AT (automatic transmission) vehicle and the CVT (continuous variable transmission) vehicle. The present invention can be applied as processing for instructions.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle control system, 2A, 2B ... Imaging part, 3 ... Image processing part, 4 ... Memory part, 5 ... Driving assistance control part, 5a ... Target recognition part, 5b ... Shift speed determination part, 5c ... Gear shift instruction control part 5c, 5d ... learning processing unit, 6 ... display control unit, 7 ... engine control unit, 8 ... brake control unit, 10 ... sensor / operator, 11 ... display unit, 30 ... gear shift indicator, 32 ... upshift instruction unit , 33 ... downshift instruction section

Claims (4)

A shift instruction unit capable of presenting an upshift instruction and a downshift instruction to the driver;
A target recognition unit for recognizing a target vehicle speed that is a distance to the target position and a vehicle speed at the target position;
Of the current shift speed and the shift speed when up-shifting or down-shifting when the vehicle is decelerated due to fuel cut, the gear speed at which the fuel consumption is reduced until the target position is reached at the target vehicle speed. A gear position determination unit for determining
A gear shift instruction control unit that controls the shift instruction unit to execute a shift instruction to the determined shift stage when the shift stage determined by the shift stage determination unit is not the current shift stage;
A driving assistance device comprising: The shift speed determination unit is a shift speed at which fuel consumption is reduced, and a shift speed at which a fuel cut distance is maximum when the target vehicle speed reaches the target position at or below the distance to the target position. The driving support device according to claim 1. The driving support device according to claim 2, wherein the shift speed determination unit performs a correction operation according to a gradient to the target position in calculating a distance at which fuel cut is possible. A learning processing unit that stores a shift time required for the gear shift operation by the driver,
The gear shift instruction control unit executes a gear shift instruction to the determined gear position when it is determined that the fuel injection return does not occur even if the gear shift for the shift time stored in the learning processing unit is performed. The driving support device according to claim 1, wherein the driving support device is controlled so as to perform the control.

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