Driving assistance systems

Abstract

The present invention provides a driver assistance device that reduces the likelihood that the driver will terminate the deceleration control by operating the accelerator pedal, by reducing the likelihood that the driver will perceive the deceleration as too strong when the vehicle is traveling downhill. [Solution] The driver assistance device is configured to perform deceleration control to slow down the vehicle in relation to an object that is located in front of the vehicle. The driver assistance device starts deceleration control when the driver performs a predetermined deceleration operation on the vehicle's accelerator pedal, and ends deceleration control when the driver performs a predetermined acceleration operation on the accelerator pedal. When the downhill condition is met, such as the vehicle traveling downhill, the deceleration control is suppressed more than when the downhill condition is not met.

Description

Technical Field

[0001] The present invention relates to a driving support device configured to execute deceleration control for decelerating a vehicle with respect to a deceleration target object existing in front of the vehicle.

Background Art

[0002] Conventionally, a driving support device that executes deceleration control with respect to a deceleration target object is known. For example, the driving support device described in Patent Document 1 (hereinafter referred to as the "conventional device") executes deceleration control when the distance to the deceleration target object is less than or equal to a threshold value and the accelerator pedal is not depressed, and cancels the execution of deceleration control when the accelerator pedal is operated while the deceleration control is being executed. When the conventional device cancels the execution of deceleration control, the greater the degree of operation of the accelerator pedal, the faster the deceleration rate of the deceleration control decreases.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] When the driver feels that the deceleration of the deceleration control is strong, the driver operates the accelerator pedal to cancel the execution of the deceleration control (that is, ends the deceleration control). After the deceleration control ends, the vehicle accelerates according to the operation of the accelerator pedal. When the vehicle is traveling on a downhill slope, the vehicle is more likely to accelerate than when the vehicle is traveling on a flat road or an uphill slope. When the vehicle is traveling on a downhill slope and the driver feels that the deceleration of the deceleration control is too strong, the driver may operate the accelerator pedal to end the deceleration control. In this case, the vehicle may accelerate faster than the vehicle acceleration intended by the driver. Such acceleration of the vehicle faster than the driver's intention is likely to cause anxiety to the driver.

[0005] This invention was made to address the aforementioned problems. Specifically, one of the objectives of this invention is to provide a driver assistance device that reduces the likelihood that the driver will terminate the deceleration control by operating the accelerator pedal, by reducing the likelihood that the driver will perceive the deceleration as too strong when the vehicle is traveling downhill.

[0006] The vehicle control device of the present invention (hereinafter referred to as "the present invention device") is configured to perform deceleration control to decelerate the vehicle with respect to an object to be decelerated located in front of the vehicle (steps 200 to 295). Furthermore, the aforementioned driving support device is If the driver performs a predetermined deceleration operation on the vehicle's accelerator pedal (30a) (step 225 "Yes"), the deceleration control is started (step 230), If the driver performs a predetermined acceleration operation on the accelerator pedal (30a) (step 245 "Yes"), the deceleration control is terminated (step 260), If the downhill condition is met, such that the vehicle is traveling downhill (step 310 "Yes"), the deceleration control is configured to be suppressed more than when the downhill condition is not met (step 310 "No", step 315) (step 335).

[0007] According to the present invention, when a downhill gradient condition is met, deceleration control is suppressed more than when the downhill gradient condition is not met. Therefore, the possibility that the driver may feel that the deceleration control is too strong when the vehicle is traveling downhill is reduced. This reduces the possibility that the driver may terminate the deceleration control by operating the accelerator pedal when the vehicle is traveling downhill. Consequently, the possibility that the vehicle may accelerate faster than the driver intended when traveling downhill, causing anxiety to the driver, is reduced. [Brief explanation of the drawing]

[0008] [Figure 1]This is a schematic system configuration diagram of a driver assistance device according to an embodiment of the present invention. [Figure 2] Figure 1 is a flowchart of the deceleration control routine executed by the CPU of the ECU. [Figure 3] Figure 1 is a flowchart of the target deceleration acquisition subroutine executed by the ECU's CPU. [Figure 4] This graph shows the time-series change in the deceleration degree of the deceleration control performed by the driving support device according to the first modified embodiment of the present invention. [Figure 5] This graph shows the time-series change in the deceleration degree of the deceleration control performed by the driving support device according to the first modified embodiment of the present invention. [Figure 6] This graph shows the time-series change in the deceleration degree of the deceleration control performed by the driving support device according to a second modified embodiment of the present invention. [Modes for carrying out the invention]

[0009] An embodiment of the present invention, the driver assistance device 10 (hereinafter also referred to as "the device 10"), is applied to a vehicle VA and comprises the components shown in Figure 1. In this specification, "ECU 20" is an electronic control device mainly comprising a microcomputer. The ECU 20 is also referred to as a control unit, controller, and computer. The microcomputer includes a CPU (processor), ROM, RAM, and interface (I / F), etc. The functions realized by the ECU 20 may be realized by multiple ECUs.

[0010] The front camera 22 acquires image data by capturing the scenery in front of the vehicle VA. The millimeter-wave radar 24 receives reflected waves from an object that has reflected millimeter waves transmitted in front of the vehicle VA, and acquires radar data regarding the position of that object relative to the vehicle VA. The ECU 20 acquires image data from the front camera 22 and radar data from the millimeter-wave radar 24. Based on the image data and radar data, the ECU 20 recognizes the object in front of the vehicle VA.

[0011] The acceleration sensor 26 measures the longitudinal acceleration Gx and vertical acceleration Gy of the vehicle VA. The vehicle speed sensor 28 measures the vehicle speed Vs, which represents the speed of the vehicle VA. The accelerator pedal sensor 30 measures the accelerator pedal operation amount AP, which represents the amount the accelerator pedal 30a is pressed. The brake pedal sensor 32 measures the brake pedal operation amount BP, which represents the amount the brake pedal 32a is pressed. The accelerator pedal operation amount AP and the brake pedal operation amount BP increase as the amount the accelerator pedal 30a and brake pedal 32a are pressed, respectively. Furthermore, the accelerator pedal operation amount AP and the brake pedal operation amount BP are "0" when the accelerator pedal 30a and brake pedal 32a are not pressed (not operated), respectively. The ECU 20 acquires the measured values ​​from these sensors 26 to 32.

[0012] The regenerative braking system 40 comprises a generator motor 42, an inverter 44, and a battery 46. The generator motor 42 is, for example, an AC synchronous motor. The output shaft of the generator motor 42 is connected to the drive wheels so that the power generated on the output shaft is transmitted to the drive wheels of the vehicle VA. The battery 46 is a rechargeable and dischargeable energy storage device. The inverter 44 is electrically connected to the battery 46. When the generator motor 42 operates as a generator, it converts the rotational (kinetic) energy of the drive wheels into electrical energy (AC power). In this case, regenerative braking force is generated in the drive wheels. The inverter 44 converts the AC power supplied from the generator motor 42 into DC power and supplies that DC power to the battery 46. In this way, the battery 46 is charged. On the other hand, when the generator motor 42 operates as an electric motor, the inverter 44 converts the DC power supplied from the battery 46 into AC power and supplies it to the generator motor 42. As a result, the generator-motor 42 is driven, and driving force is applied to the drive wheels. Thus, the generator-motor 42 functions not only as a drive actuator that applies driving force to the drive wheels, but also as a braking actuator that applies regenerative braking force to the drive wheels.

[0013] The friction braking system 50 includes a hydraulic circuit 52 that functions as a braking actuator. The hydraulic circuit 52 operates the wheel cylinders (not shown) by supplying hydraulic pressure to them, which are arranged corresponding to each wheel. When the wheel cylinders are operated, the brake pads (not shown) are pressed against the brake discs of each wheel, generating a frictional braking force on each wheel.

[0014] <Deceleration Control> The ECU20 performs deceleration control for objects that decelerate in front of the vehicle VA. Deceleration control is a control to slow down the vehicle VA. The ECU20 recognizes objects that decelerate based on image data and radar data. For example, objects that decelerate include preceding vehicles, curved roads, traffic lights that instruct stopping, and stop lines. A preceding vehicle is another vehicle traveling in the same lane as vehicle VA and located in front of vehicle VA. When the ECU20 recognizes an object that decelerates, it obtains a target deceleration Gtgt to achieve "one of target 1 to target 3 depending on the object that decelerates".

[0015] <Objective 1> If the object to be decelerated is a preceding vehicle, the interval time Tve will be greater than or equal to the threshold time Tth. The interval time Tve is the time from when the preceding vehicle passes a certain point until vehicle VA passes that point. <Objective 2> If the object to be decelerated is a curved road, the vehicle speed Vs will be the "appropriate curve speed Vcv for vehicle VA to travel on the curved road". The curve speed Vcv is obtained based on the curvature of the curved road. The ECU20 detects the white line of the lane in which vehicle VA is traveling based on image data and obtains the curvature based on that white line. <Objective 3> If the object to be decelerated is a traffic light or stop line, the vehicle speed Vs will be the stopping speed Vst at a target point a predetermined distance before the traffic light or stop line.

[0016] <Starting Conditions> If both of the following conditions S1 and S2 are met, the ECU 20 determines that the starting conditions have been met and starts deceleration control. Condition S1: The target deceleration Gtgt is greater than or equal to the threshold deceleration Gth. Condition S2: The driver has performed a deceleration intention operation on the accelerator pedal 30a. Details of the deceleration intention operation will be described later.

[0017] <End condition> When the above target corresponding to the deceleration target object is achieved, the ECU 20 determines that the end condition is satisfied and ends the deceleration control.

[0018] In addition, when the driver performs an acceleration intention operation indicating an acceleration intention on the accelerator pedal 30a, the ECU 20 determines that an accelerator override has occurred and ends the deceleration control.

[0019] (Outline of operation) The ECU 20 acquires the inclination θ of the road on which the vehicle VA is traveling based on the acceleration Gy measured by the acceleration sensor 26. When the vehicle VA is traveling on a flat road, the inclination θ is "0 deg". When the vehicle VA is traveling downhill, the inclination θ becomes a negative value. When the vehicle VA is traveling uphill, the inclination θ becomes a positive value.

[0020] The ECU 20 determines whether the downhill condition is satisfied based on the inclination θ. When the ECU 20 determines that the downhill condition is satisfied, it determines that the vehicle VA is traveling downhill. For example, when the inclination θ is less than or equal to a threshold inclination θth set to a predetermined value smaller than 0, the ECU 20 determines that the downhill condition is satisfied.

[0021] When the downhill condition is satisfied, the ECU 20 suppresses the deceleration control more (reduces the degree of intervention of the deceleration control) than when the downhill condition is not satisfied.

[0022] When the downhill condition is satisfied, the deceleration control is suppressed more than when the downhill condition is not satisfied. Therefore, it is possible to reduce the possibility that the driver steps on the accelerator pedal 30a because the deceleration of the deceleration control is too strong. As a result, when the vehicle VA is traveling downhill, an accelerator override occurs and the deceleration control ends, and it is possible to reduce the possibility that the vehicle VA accelerates faster than the driver's intention. Therefore, according to the present device 10, it is possible to reduce the possibility of giving the driver anxiety when the vehicle VA is traveling downhill.

[0023] (Specific Operation) The CPU of ECU20 executes the deceleration control routine shown in the flowchart in Figure 2 at predetermined intervals. When an appropriate time arrives, the CPU starts processing from step 200 in Figure 2, and in step 205, the CPU determines whether the execution flag Xexe is "0".

[0024] The execution flag Xexe is set to "1" when deceleration control is performed and to "0" when deceleration control is not performed. The execution flag Xexe is set to "0" in the initialization routine. The initialization routine is executed by the CPU when the ignition key switch (not shown) of the vehicle VA is changed from the off position to the on position.

[0025] If the execution flag Xexe is "0" (step 205 "Yes"), in step 210 the CPU determines whether or not it has recognized the object to be decelerated based on the image data and radar data.

[0026] If an object to be decelerated is recognized (step 210 "Yes"), the CPU executes steps 215 and 220. Step 215: The CPU executes a target deceleration acquisition subroutine to obtain the target deceleration Gtgt. The larger the target deceleration Gtgt, the stronger the vehicle VA deceleration. Details of the target deceleration acquisition subroutine will be described later. Step 220: The CPU determines whether the target deceleration Gtgt is greater than or equal to the threshold deceleration Gth.

[0027] If the target deceleration Gtgt is greater than or equal to the threshold deceleration Gth (step 220 "Yes"), in step 225 the CPU determines whether the driver has performed a deceleration operation on the accelerator pedal 30a. Specifically, if both the first operating condition, that the accelerator pedal operation amount AP is less than or equal to the deceleration start operation amount APst, and the second operating condition, that the change amount ΔAP of the accelerator pedal operation amount AP is less than or equal to the "deceleration start change amount ΔAPst, which is set to a predetermined negative value", are met, the CPU determines that the driver has performed a deceleration operation on the accelerator pedal 30a. The change amount ΔAP is obtained by subtracting the "accelerator pedal operation amount APp at a predetermined time prior to the present" from the current accelerator pedal operation amount AP. If the driver releases the accelerator pedal 30a, the change amount ΔAP will be a negative value.

[0028] If the driver performs a deceleration operation on the accelerator pedal 30a (step 225 "Yes"), the CPU executes steps 230 and 235. Step 230: The CPU sets the execution flag Xexe to "1". Step 235: The CPU controls at least the regenerative braking system 40, of the two friction braking systems 40, to generate a braking force Fd such that the acceleration Gx of the vehicle VA matches the target deceleration Gtgt. Specifically, the CPU obtains the braking force Fd required to match the acceleration Gx to the target deceleration Gtgt. If the braking force Fd is less than or equal to the "maximum braking force that the regenerative braking system 40 can generate", the CPU generates the braking force Fd in the regenerative braking system 40. If the braking force Fd is greater than the above maximum braking force, the CPU generates the maximum braking force in the regenerative braking system 40 and generates the "braking force obtained by subtracting the above maximum braking force from the braking force Fd" in the friction braking system 50. After that, the process proceeds to step 295, and the CPU terminates this routine.

[0029] If no object to be decelerated is recognized (Step 210 "No"), if the target deceleration Gtgt is less than the threshold deceleration Gth (Step 220 "No"), or if the driver does not perform a deceleration operation (Step 225 "No"), the process proceeds to Step 295. As a result, deceleration control is not initiated.

[0030] If the execution flag Xexe is "1" when the process proceeds to step 205 (step 205 "No"), in step 240 the CPU determines whether the termination condition is met. Specifically, if the object to be decelerated is a preceding vehicle, the termination condition is met when the interval time Tve is equal to or greater than the threshold time tth. If the object to be decelerated is a curved road, the termination condition is met when the vehicle speed Vs matches the curved vehicle speed Vcv. If the object to be decelerated is a traffic light or stop line, the termination condition is met when the acceleration Gx matches the "stopping deceleration required for the vehicle speed Vs to match the stopping vehicle speed Vst at the target point".

[0031] If the termination condition is not met (step 240 "No"), in step 245 the CPU determines whether or not an accelerator override has occurred. The CPU determines that an accelerator override has occurred if either of the following conditions is met: the change amount ΔAP is greater than or equal to "an acceleration change amount ΔAPac set to a predetermined positive value", or the accelerator pedal operation amount AP is greater than the deceleration start operation amount APst.

[0032] If no accelerator override has occurred (step 245 "No"), in step 250 the CPU determines whether or not brake override has occurred. If the brake pedal 32a is pressed, the CPU determines that brake override has occurred.

[0033] If no brake override occurs (step 250 "No"), in step 255 the CPU executes the target deceleration acquisition subroutine, and the process proceeds to step 235.

[0034] If the termination condition is met (step 240 "Yes"), if an accelerator override occurs (step 245 "Yes"), or if a brake override occurs (step 250 "Yes"), in step 260 the CPU sets the execution flag Xexe to "0", and the process proceeds to step 295.

[0035] If the process proceeds to step 215 or step 255, the CPU starts processing from step 300 in Figure 3, and the process proceeds to step 305. In step 305, the CPU determines whether the accelerator pedal operation amount AP is greater than "0".

[0036] If the accelerator pedal operation amount AP is greater than "0" (step 305 "Yes"), in step 310 the CPU determines whether the downhill gradient condition is met.

[0037] If the downhill gradient condition is not met (step 310 "No"), the CPU executes steps 315 through 325. Step 315: The CPU selects a normal driving force map corresponding to the accelerator pedal operation amount AP. The device 10 stores a normal driving force map and a suppressed driving force map for each accelerator pedal operation amount AP. These driving force maps define the relationship between vehicle speed Vs and driving force DF. According to these driving force maps, the driving force DF decreases as the vehicle speed Vs increases. In the normal driving force map and the suppressed driving force map, the driving force DF becomes a negative value when the vehicle speed Vs exceeds a certain vehicle speed. When the driving force DF becomes a negative value, a braking force is applied to the wheels. Note that when the driving force DF becomes a negative value, the driving force DF corresponding to the same vehicle speed Vs is greater in the suppressed driving force map than in the normal driving force map. That is, the braking force in the suppressed driving force map is more suppressed than the braking force in the normal driving force map.

[0038] Step 320: The CPU obtains the drive force DF by applying the vehicle speed Vs to the selected normal drive force map, and obtains the target deceleration Gtgt to generate the braking force corresponding to that drive force DF. The target deceleration Gtgt is "0" when the drive force DF is positive.

[0039] Step 325: The CPU determines whether the target deceleration Gtgt is greater than the upper limit deceleration Glmt.

[0040] If the target deceleration Gtgt is greater than the upper limit deceleration Glmt (step 325 "Yes"), in step 330 the CPU sets the target deceleration Gtgt to the upper limit deceleration Glmt. Therefore, the target deceleration Gtgt will not be greater than the upper limit deceleration Glmt. After that, the process proceeds to step 395, and the CPU terminates this routine. After that, the process proceeds to step 220 or step 235 as shown in Figure 2. If the target deceleration Gtgt is less than or equal to the upper limit deceleration Glmt (step 325 "No"), the process proceeds to step 395.

[0041] If the downhill gradient condition is met when the process proceeds to step 310 (step 310 "Yes"), in step 335, the CPU selects a suppression force map corresponding to the accelerator pedal operation amount AP. Then, the process proceeds to step 320, where the CPU obtains the target deceleration Gtgt based on the drive force DF obtained by applying the vehicle speed Vs to the selected suppression force map.

[0042] If the accelerator pedal operation amount AP is "0" when the process proceeds to step 305 (step 305 "No"), in step 340, the CPU obtains the target deceleration Gtgt according to the type of object being decelerated, as described above. After that, the process proceeds to step 325.

[0043] As explained above, when the downhill gradient condition is met, the target deceleration Gtgt is obtained using the suppression drive force map. Therefore, when the downhill gradient condition is met, the target deceleration Gtgt is smaller than when the downhill gradient condition is not met. In other words, when the downhill gradient condition is met, deceleration control is suppressed more than when the downhill gradient condition is not met. As a result, when deceleration control is executed while the vehicle VA is traveling downhill, the possibility of the driver pressing the accelerator pedal 30a is reduced, thus reducing the possibility of the vehicle VA accelerating faster than the driver intended and causing anxiety to the driver.

[0044] (First Modification) In this modification, the ECU20 performs a process (first upper limit suppression process) that reduces the upper limit deceleration Glmt to a smaller value than when the downhill gradient condition is not met, when the downhill gradient condition is met. In other words, when the downhill gradient condition is met, the ECU20 uses an upper limit deceleration Glmt' that is smaller than the upper limit deceleration Glmt when the downhill gradient condition is not met. Figure 4 shows the time-series change of the target deceleration Gtgt when the downhill gradient condition is not met and when the downhill gradient condition is met. As shown in Figure 4, when the downhill gradient condition is met, the deceleration control is suppressed more than when the downhill gradient condition is not met.

[0045] Furthermore, if the time evolution of the target deceleration Gtgt (i.e., the time derivative of deceleration, hereinafter referred to as "jerk J") is greater than the upper limit jerk Jlmt, the ECU20 sets the target deceleration Gtgt to a value such that jerk J is less than or equal to the upper limit jerk Jlmt. This prevents jerk J from exceeding the upper limit jerk Jlmt. In this modified example, the CPU may perform a process (second upper limit suppression process) to reduce the upper limit jerk Jlmt when the downhill slope condition is met compared to when the downhill slope condition is not met. Figure 5 shows the time series change of the target deceleration Gtgt when the downhill slope condition is not met and when the downhill slope condition is met.

[0046] Furthermore, if the downward slope condition is met, it is sufficient for at least one of the first upper limit suppression process and the second upper limit suppression process to be executed.

[0047] (Second Modification) In this modification, the ECU 20 executes at least one of the start timing process and the end timing process when the downhill gradient condition is met. The start timing process delays the start timing of the deceleration control compared to when the downhill gradient condition is not met (making it more difficult to meet the start condition). The end timing process advances the end timing of the deceleration control compared to when the downhill gradient condition is not met (making it easier to meet the end condition). Because the execution time of the deceleration control is shortened by delaying the start timing and / or advancing the end timing, the deceleration control is suppressed.

[0048] The start timing process will be explained in detail. When the downhill slope condition is met, the ECU20 sets the threshold deceleration Gth used in step 220 shown in Figure 2 to a larger value than when the downhill slope condition is not met. Furthermore, when the downhill slope condition is met, the ECU20 sets the deceleration start operation amount APst used in step 225 shown in Figure 2 to a smaller value than when the downhill slope condition is not met, and also sets the deceleration start change amount ΔAPst to a smaller value than when the downhill slope condition is not met. Figure 6 shows the time-series change of the target deceleration Gtgt when the start timing process is not performed (when the downhill slope condition is not met) and when the start timing process is performed (when the downhill slope condition is met). Note that it is sufficient for at least one of the threshold deceleration Gth, deceleration start operation amount APst, and deceleration start change amount ΔAPst to be changed in such a way that the start condition is less likely to be met.

[0049] The termination timing processing will be explained in detail. When the downhill gradient condition is met, ECU20 reduces the threshold time Tth used for the termination condition when the object to be decelerated is a preceding vehicle, compared to when the downhill gradient condition is not met. When the downhill gradient condition is met, ECU20 increases the curve speed Vcv used for the termination condition when the object to be decelerated is a curved road, compared to when the downhill gradient condition is not met. When the downhill gradient condition is met, ECU20 reduces the stopping deceleration used for the termination condition when the object to be decelerated is a traffic light or stop line, compared to when the downhill gradient condition is not met.

[0050] If at least one of the first and second operating conditions is met, the CPU may determine that the driver has performed an operation with the intention of decelerating. Furthermore, if both the third and fourth operating conditions are met, the CPU may determine that the driver has performed an operation with the intention of accelerating. Note that the deceleration start operation amount APst used in the first operating condition and the deceleration start operation amount APst used in the fourth operating condition may be different values. It is also possible to combine the above embodiment with at least one of the first and second modified examples.

[0051] This device 10 is applicable to vehicles such as engine-powered vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles, and is also applicable to autonomous vehicles. [Explanation of symbols]

[0052] 10...Driving assistance system, 30...Accelerator pedal sensor, 40...Regenerative braking system, 50...Friction braking system.

Claims

1. In a driver assistance device configured to perform deceleration control to decelerate the vehicle in relation to an object located in front of the vehicle, The aforementioned driving support device, When the driver performs a predetermined deceleration operation on the vehicle's accelerator pedal, the deceleration control is initiated. When the driver performs a predetermined acceleration operation on the accelerator pedal, the deceleration control is terminated. A driving assistance device configured to suppress the deceleration control more than when the downhill gradient condition is met, such that the vehicle is traveling on a downhill slope.

2. In the driving support device according to claim 1, The aforementioned driving support device, In the deceleration control described above, the vehicle is decelerated by an operating deceleration determined based on the vehicle's speed and the amount of operation of the accelerator pedal. When the aforementioned downhill gradient condition is met, the deceleration control is suppressed by reducing the operating deceleration compared to when the aforementioned downhill gradient condition is not met. A driver assistance system configured in such a way.

3. In the driving support device according to either claim 1 or claim 2, The driving support device is configured to suppress the deceleration control by performing at least one of the following when the downhill gradient condition is met: a first upper limit suppression process that reduces the upper limit of the deceleration degree in the deceleration control to a lower value than when the downhill gradient condition is not met, and a second upper limit suppression process that reduces the upper limit of the time change of the deceleration in the deceleration control to a lower value than when the downhill gradient condition is not met.

4. In the driving support device according to either claim 1 or claim 2, The driving assistance device is configured to suppress the deceleration control by performing at least one of the following when the downhill gradient condition is met: a start timing process that delays the start timing of the deceleration control compared to when the downhill gradient condition is not met, and an end timing process that speeds up the end timing of the deceleration control compared to when the downhill gradient condition is not met.

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