Travel control system of vehicle

Abstract

To enable engine rotation speed adjustment by blipping operation while preventing an unnecessary engine rotation speed increase accompanied with shift operation during acceleration by an ACC function in an MT vehicle.SOLUTION: In a travel control system of an MT vehicle including an engine controller and an ACC controller, the engine controller is configured to reject a torque request from the ACC controller and control an engine output to a torque target value by determination of the engine controller when a clutch is turned on during actuation of an ACC function.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle cruise control system, and more particularly to a cruise control system for a manual transmission vehicle. [Background technology]

[0002] Adaptive cruise control (ACC) is a well-known driving support function for vehicles. This ACC function is a driving control function that drives at a constant speed at a set vehicle speed when there is no preceding vehicle ahead of the vehicle, and follows the preceding vehicle while maintaining a set inter-vehicle time when there is a preceding vehicle ahead of the vehicle traveling slower than the set vehicle speed. Initially, this function was limited to high-speed ranges, but has since been adapted to support all vehicle speed ranges, including deceleration, stopping, and restarting.

[0003] The ACC function is used not only in automatic transmission vehicles (AT vehicles) but also in manual transmission vehicles (MT vehicles). However, in MT vehicles, to make it compatible with all vehicle speeds, the driver must appropriately change gears in accordance with the deceleration and stopping caused by the vehicle system's tracking control, which requires a certain level of driving skill. For this reason, the ACC function is deactivated when the vehicle speed drops below a lower limit (for example, 30 km / h). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-46085 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, it was found that while accelerating with the ACC function in a manual transmission vehicle, the engine would rev up the moment the clutch was released when the driver changed gears. In other words, while accelerating with the ACC function, the engine controller receives the torque request from the ACC controller and controls the engine output, so the time lag between when the ACC controller determines that the clutch has been released and when it releases the torque request (acceleration request) to the engine controller causes the engine speed to rise.

[0006] On the other hand, some drivers engage the clutch while adjusting the engine speed with the accelerator pedal to target the engine speed corresponding to the gear after shifting in order to avoid a sudden change in engine speed (so-called gear shift shock) during gear shifting. This operation is called blipping, but when shifting during acceleration using the ACC function, the torque request is released as described above, so blipping cannot be performed.

[0007] The present invention has been made in consideration of the above-described circumstances, and its object is to enable engine speed adjustment by blipping operation while preventing unnecessary increases in engine speed that accompany gear shifting operation during acceleration using the ACC function in a manual transmission vehicle. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a clutch for releasably transmitting the output of the engine to the transmission; A clutch pedal for performing a release operation of the clutch; a clutch information unit that transmits an ON signal when the clutch pedal is depressed; an engine controller for controlling the output of the engine in response to a torque demand; an ACC controller that controls the speed of the vehicle to execute an ACC function in which the vehicle travels at a set vehicle speed when there is no preceding vehicle ahead of the vehicle, and travels in a following manner while maintaining a set inter-vehicle time when there is a preceding vehicle ahead of the vehicle traveling at a speed slower than the set vehicle speed; A vehicle driving control system comprising: When the clutch is turned on during operation of the ACC function, the engine controller is configured to reject the torque request from the ACC controller and control the engine output to a torque target value determined by the engine controller. The present invention relates to a vehicle driving control system. Effect of the Invention

[0009] The vehicle cruise control system according to the present invention, with the above configuration, does not need to wait for the torque request from the ACC controller to be released and does not generate a time lag, so it can prevent unnecessary increases in engine speed due to gear shifting. In addition, after the clutch is released, the engine controller can control the engine output independently of the torque request from the ACC controller, which has the advantage of allowing the engine speed to be adjusted by blipping. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a vehicle cruise control system according to an embodiment of the present invention; [Diagram 2] 4 is a flowchart showing a driving control according to the embodiment of the present invention. [Diagram 3] 4 is a flowchart showing a driving control according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the vehicle cruise control system according to the embodiment of the present invention is made up of an engine controller 10 that controls the output of the engine, a brake controller 20 that controls the braking force of the brake system, an ACC controller 30 for executing the ACC function, a preceding vehicle detection means 31, and a group of sensors for acquiring state values ​​used for cruise control.

[0012] The engine controller 10 constitutes an electronically controlled throttle system that controls the throttle opening of the engine by a throttle actuator in response to the accelerator pedal depression amount (torque demand) of the driver detected by an accelerator pedal sensor 12.

[0013] In addition to the accelerator pedal depression amount, the engine controller 10 is configured to acquire various detection values ​​indicating the engine operating state and the vehicle traveling state via the in-vehicle network, such as the engine speed detected by the engine rotation sensor 11 (crank angle sensor, cam angle sensor, etc.), clutch-on information detected by the clutch pedal sensor 13, and vehicle speed calculated from the detection value of the wheel speed sensor 21, and to maintain the engine operating state at an optimum level.

[0014] The brake controller 20 controls an electric hydraulic unit (brake actuator), controls the hydraulic pressure (basic brake pressure) generated according to the driver's depression force input to the brake pedal, and controls the braking force of the brake device of each wheel. The electric hydraulic unit includes an electric pump and a control valve for switching between its hydraulic system and the hydraulic system on the master cylinder side. The brake controller 20 is built into the electric hydraulic unit as an ESC controller (ECU), and configures an ESC system together with a wheel speed sensor 21 and a steering angle sensor and a yaw rate sensor (not shown). The brake controller 20 also controls an electric parking brake via an EPB controller (not shown).

[0015] The preceding vehicle detection means 31, which constitutes the ACC system together with the ACC controller 30, can be one or more detection devices such as millimeter wave radar, monocular camera, stereo camera, LIDAR, etc. that have the function of detecting the presence of a preceding vehicle or object (obstacle, structure) in front of the vehicle and can measure the relative distance (relative inter-vehicle time) between the vehicle and the preceding vehicle or obstacle.

[0016] Based on the detection information from the preceding vehicle detection means 31 and the vehicle speed calculated from the detection value of the wheel speed sensor 21, the ACC controller 30 issues acceleration / deceleration commands to the engine controller 10 and the brake controller 20 instead of the driver's accelerator / brake operation, and executes adaptive cruise control (constant speed driving / follow-up driving control).

[0017] That is, the engine controller 10, which receives a torque request (acceleration / deceleration command) from the ACC controller 30, controls the actuator output (throttle opening) to control the torque of the engine and control the vehicle speed. Also, the brake controller 20, which receives a deceleration command from the ACC controller 30, controls the brake actuator to control the braking force of the brake device of each wheel, thereby controlling the vehicle speed.

[0018] By the speed control as described above by the ACC controller 30, if there is no preceding vehicle ahead, the vehicle maintains the set vehicle speed and travels at a constant speed, and if there is a preceding vehicle ahead of the vehicle traveling slower than the set vehicle speed, the vehicle follows the preceding vehicle while maintaining a distance according to the set inter-vehicle time (time gear up = inter-vehicle distance / own vehicle speed).

[0019] The ACC controller 30 is configured so that a setting switch 32 provided at the driver's seat (steering wheel, etc.) can be used to perform operations such as activating / deactivating the ACC function and setting the set vehicle speed and set inter-vehicle time.

[0020] The engine controller 10, brake controller 20, and ACC controller 30 described above are all composed of a computer (ECU) consisting of a ROM for storing control programs and setting data, a RAM for temporarily storing the results of calculation processing, a CPU for performing calculation processing, a communication I / F, etc., and are connected to the sensors via the in-vehicle network so that they can communicate with each other.

[0021] (Torque control when shifting gears while ACC is in operation 1) In manual transmission vehicles, the driver is required to change gears as necessary even when the ACC function is operating. When driving at a set speed at high speeds on highways and following other vehicles, the frequency of gear changes is low, so just like in the case of automatic transmission vehicles, the ACC function frees the driver from having to operate the accelerator and brakes, significantly reducing the burden on the driver, especially on long-distance driving.

[0022] On the other hand, on ordinary roads where traffic jams or traffic lights force you to stop temporarily, it is necessary to change gears appropriately in accordance with speed control, which demands a certain level of driving skill. For this reason, the ACC function is generally deactivated when the vehicle is below the minimum speed (e.g. 30km / h) (or in second gear or lower), but as described below, it is also possible to use the function at all vehicle speeds, including decelerating to a stop and restarting.

[0023] When shifting up or down while accelerating using the ACC function, the driver depresses the clutch pedal to release the clutch, operates the shift lever to change gear, and then gradually engages the clutch, which transmits engine torque to the drive wheels and transitions to driving in the new gear.

[0024] At this time, the engine controller 10 receives clutch-on information from the clutch pedal sensor 12. Conventionally, however, the recognition information of the engine controller 10 was referred to by the ACC controller 30, and the acceleration request from the ACC controller 30 to the engine controller 10 was temporarily released, so as already mentioned, there was a problem that the engine speed would increase between the time the ACC controller 30 determined that the clutch was on and the time the acceleration request was released.

[0025] Therefore, in the driving control system according to the present invention, when clutch on is detected by the clutch pedal sensor 12 during acceleration by the ACC function, the engine controller 10 assumes that a shift operation has been initiated, rejects (i.e., ignores) the torque request from the ACC controller 30, and controls the engine output to a target shift torque value (TDe; idling level) set in the engine controller 10 such that the engine does not stall.

[0026] With this configuration, the engine controller 10 can immediately reduce the torque of the engine at its own discretion without waiting for the torque request to be released by the ACC controller 30, thereby preventing unnecessary increases in engine speed due to gear shifting operations.

[0027] Furthermore, according to the above configuration, the engine controller 10 ignores the torque request from the ACC controller 30 after the clutch is released, and therefore can control the engine output independently of the torque request from the ACC controller 30. Therefore, as described below, it is possible to allow the engine speed to be adjusted by a blipping operation.

[0028] (Blipping operation when changing gears while ACC is operating) That is, in the cruise control system according to the present invention, if the torque demand value (TDa) from the accelerator pedal sensor 12 exceeds the gear shift torque target value (TDe) set by the engine controller 10 during the period from when the clutch is released until engagement of the clutch is resumed (while the clutch is released), the engine controller 10 assumes that the driver has intentionally performed an accelerator operation (blipping operation) and controls the engine output in accordance with the torque demand value (TDa) from the accelerator pedal sensor 12.

[0029] FIG. 2 shows a flow chart according to an embodiment of the torque control during a gear shift operation while the ACC is operating as described above.

[0030] When the ACC function is operating (step 101; YES), if clutch pedal ON is detected (step 110; YES), it is determined that a shift operation has begun, and accelerator pedal operation during the shift is monitored (step 120).

[0031] If accelerator pedal operation is detected during gear shifting (step 120; YES), the torque request value (TDa) due to accelerator operation is compared with the gear shift torque target value (TDe) set by the engine controller 10 (step 121).

[0032] If the torque demand value (TDa) due to accelerator operation is greater than the torque target value for shifting (TDe) (step 121; YES), it is assumed that the driver has performed a blipping operation, and the torque demand value (TDa) due to accelerator operation is set as the torque target value (TTR) for engine output control (step 130).

[0033] If the torque request value (TDa) due to accelerator operation is equal to or less than the torque target value for gear shifting (TDe) (step 121; NO), and if accelerator pedal operation is not detected during gear shifting (step 120; NO), it is determined that there is no significant accelerator pedal operation, and the torque target value for gear shifting (TDe) set by the engine controller 10 is set as the torque target value (TTR) for engine output control (step 131).

[0034] If the clutch pedal is not detected as on (clutch released) while the ACC function is operating (step 110; NO), it is determined that no gear shifting operation is being performed, and the torque request value (TDacc) of the ACC controller 30 is set as the torque target value (TTR) for engine output control (step 132).

[0035] (Torque control when shifting gears while ACC is in operation 2) As described above, when the driver starts a gear shift operation while the ACC is operating, the engine controller 10 transitions to a control mode that rejects the torque request from the ACC controller 30. Therefore, when the gear shift operation is completed, the engine controller 10 must accept the torque request from the ACC controller 30 and return to engine output control based on the torque request of the ACC controller 30.

[0036] Therefore, in the driving control system of the present invention, after the clutch is turned on, the engine controller 10 rejects the torque request from the ACC controller 30, while monitoring the engine speed and the clutch engagement rate, and reflects the torque request from the ACC controller 30 in the control of the engine output at a ratio according to the clutch engagement rate, thereby enabling a smooth return to the ACC mode.

[0037] The clutch engagement rate α is the ratio of the transmission input shaft rotation speed Nc to the engine rotation speed N detected by the engine rotation sensor 11, and can be estimated as follows using the vehicle speed V, gear ratio Gn, final reduction ratio F, effective tire radius R, and coefficient k (unit adjustment and N / V ratio offset in a fully engaged state). Clutch engagement ratio α = Nc / N = kV / GnFRN

[0038] That is, the rotation speed Nc according to the clutch engagement rate α is transmitted to the transmission with respect to the engine rotation speed N. Therefore, the engine controller 10 monitors the engine rotation speed N and the clutch engagement rate α to determine the clutch engagement state (half-clutch state), and adjusts the rate at which torque requests from the ACC controller 30 are accepted according to the clutch engagement rate α, so that the driver can return to ACC driving while suppressing engine revving simply by engaging the clutch.

[0039] (Do not operate the accelerator after shifting gears while ACC is operating) As described above, if a torque request due to the driver's accelerator operation is added during the period in which the torque request from the ACC controller 30 is reflected in the control of the engine output at a rate corresponding to the clutch engagement rate, it is expected that the engine will rev up. During this period, the blipping operation described above has ended, so if there is an accelerator operation, it is likely to be an erroneous operation. Therefore, the engine controller 10 rejects the torque request due to the accelerator operation for a predetermined time from when partial engagement of the clutch is detected, thereby suppressing engine rev up and inadvertent acceleration and allowing a smooth return to the ACC mode.

[0040] FIG. 3 shows a flow chart according to an embodiment of the torque control after a gear shift operation during the operation of the ACC as described above.

[0041] When the ACC function is in operation (step 201; YES) and the torque request from the ACC controller 30 is an acceleration request (step 202; YES), the engine controller 10 monitors the engine speed and the clutch engagement rate (α) and calculates the clutch engagement rate (α). If it is 0% (step 211; YES), it is determined that the clutch is released, i.e., the gear shift operation is in progress (or coasting), and the gear shift torque target value (TDe) set by the engine controller 10 so as not to cause engine stall is set as the torque target value (TTR) for engine output control (step 231).

[0042] If the ACC function is operating (step 201; YES), the torque request from the ACC controller 30 is requesting acceleration (step 202; YES), and the clutch engagement rate (α) is not 100% (step 212; NO), it is determined that the clutch engagement rate (α) is between 0% and 100%, that is, a half-clutch state (step 213), and the rate at which the torque request (TDacc) from the ACC controller 30 is accepted is adjusted according to the clutch engagement rate (α), and this is set as the torque target value (TTR) for engine output control (step 233).

[0043] If the ACC function is operating (step 201; YES), the torque request from the ACC controller 30 is requesting acceleration (step 202; YES), and the clutch engagement rate α is 100% (step 212; YES), it is determined that clutch engagement is complete after the above-mentioned adjustments have been made, and the torque request value (TDacc) from the ACC controller 30 is set as the torque target value (TTR) for engine output control (step 232), as in normal driving in ACC mode.

[0044] When the ACC function is operating (step 201; YES) and the torque request from the ACC controller 30 is not an acceleration request (step 202; NO), it is determined that deceleration is being requested, and the engine controller 10 reduces the torque to a torque request value (TDeB) that does not cause the engine to stall as the torque target value (TTR) for engine output control, thereby applying engine braking (step 234).

[0045] With the above control, the driver can return to ACC driving while suppressing engine revving simply by engaging the clutch after shifting. In addition, the above-described series of controls from the clutch release operation during shifting to the clutch engagement operation after shifting can be applied not only to shifting, but also to control when accelerating after deceleration and stopping, and is also effective when implementing the all-speed ACC mode in MT vehicles. Examples of such applications are described below.

[0046] (Torque control during start-up acceleration after deceleration and stopping with all-speed ACC) When the preceding vehicle decelerates and stops while following the preceding vehicle using the ACC function, or when the vehicle catches up with a preceding vehicle that is traveling at a constant speed and decelerating to a stop, the ACC controller 30 issues a deceleration command to the engine controller 10 and the brake controller 20 (or a braking / driving controller that integrates them), and the vehicle decelerates and stops while maintaining a specified distance from the preceding vehicle.

[0047] In this case, in the case of a manual transmission vehicle, when the vehicle is traveling at high speed, it is desirable for the driver to perform a gear change operation in accordance with the deceleration of the vehicle, and when the vehicle speed becomes low, the driver must depress the clutch pedal and release the clutch before stopping. In response to this clutch release operation, the engine controller 10 rejects the torque request from the ACC controller 30 in the same manner as described above, and controls the engine output to a torque target value (idling level) that does not cause the engine to stall, as determined by the engine controller 10. In other words, the engine will transition to idling (it can also transition to idling stop).

[0048] Thereafter, if the preceding vehicle starts moving within a predetermined time, the ACC controller 30 issues an acceleration request for restarting, but the engine controller 10 rejects the torque request from the ACC controller 30, so the vehicle does not automatically follow and start moving. Meanwhile, the engine controller 10 continues to monitor the engine speed and clutch engagement rate after the clutch release operation, and when the driver operates the clutch pedal to engage the clutch, the torque request from the ACC controller 30 is reflected in the control of the engine output at a rate according to the clutch engagement rate, and the vehicle can restart and accelerate to a set vehicle speed or move into following driving.

[0049] As already mentioned, if a torque request due to the driver's accelerator operation is added during the period in which the torque request from the ACC controller 30 is reflected in the control of the engine output at a rate according to the clutch engagement rate as described above, there is a risk of the engine revving up. In addition, since the ACC controller 30 performs distance control, the vehicle will not get too close to the vehicle ahead, but a situation in which an acceleration request and a deceleration request (braking request) are made simultaneously should be avoided.

[0050] Therefore, when restarting after decelerating and stopping in ACC mode, it is preferable that the engine controller 10 be configured to reject the torque request due to accelerator operation for a second predetermined time period that is longer than the clutch engagement during ACC driving described above.

[0051] On the other hand, when restarting after deceleration and stopping in the ACC mode, if there is no preceding vehicle within a set distance range ahead of the host vehicle, the ACC controller 30 may be configured to issue a torque request to the engine controller 10 that is higher than when the vehicle is traveling. This makes it possible to expect good starting acceleration performance even in a configuration in which restarting is performed only by the driver's clutch pedal operation.

[0052] Although several embodiments of the present invention have been described above, it should be noted that the present invention is not limited to the above-described embodiments, and further modifications and variations are possible within the scope of the present invention based on the technical concept of the present invention. [Explanation of symbols]

[0053] 10 Engine Controller 11 Engine revolution sensor 12 Accelerator pedal sensor 13 Clutch pedal sensor 20 Brake controller 21 Wheel speed sensor 30 ACC Controller 31 Preceding vehicle detection means 32 Setting Switch

Claims

1. a clutch for releasably transmitting the output of the engine to the transmission; A clutch pedal for performing a release operation of the clutch; a clutch information unit that transmits an ON signal when the clutch pedal is depressed; an engine controller for controlling the output of the engine in response to a torque demand; an ACC controller that controls the speed of the vehicle to execute an ACC function in which the vehicle travels at a set vehicle speed when there is no preceding vehicle ahead of the vehicle, and travels in a following manner while maintaining a set inter-vehicle time when there is a preceding vehicle ahead of the vehicle traveling at a speed slower than the set vehicle speed; A vehicle driving control system comprising: When the clutch is turned on during operation of the ACC function, the engine controller is configured to reject a torque request from the ACC controller and control an engine output to a torque target value determined by the engine controller. A vehicle driving control system comprising:

2. 2. The vehicle driving control system according to claim 1, wherein when the clutch is turned on while the ACC function is operating and the engine controller rejects the torque request from the ACC controller, if an accelerator operation by a driver is detected, the system is configured to control engine output in accordance with the torque request due to the accelerator operation.

3. 3. The vehicle driving control system according to claim 2, wherein after the clutch is released while the ACC function is operating and the engine controller rejects the torque request from the ACC controller, the system is configured to monitor the engine speed and the clutch engagement rate, and to reflect the torque request from the ACC controller in control of the engine output at a rate according to the clutch engagement rate.

4. 4. The vehicle driving control system according to claim 3, further comprising: a torque controller configured to detect whether the clutch is disengaged during operation of the ACC function and whether the engine controller rejects the torque request from the ACC controller, and to reject the torque request due to the accelerator operation for a predetermined time from when partial engagement of the clutch is detected.

5. 5. The vehicle driving control system according to claim 4, wherein when the clutch is released by the driver before deceleration and stop by the ACC function, and the vehicle is restarted from a state stopped by the ACC function by reflecting a torque request from the ACC controller in control of engine output at a ratio corresponding to a clutch engagement rate, the torque request due to accelerator operation is rejected for a second predetermined time period that is longer than the predetermined time period.

6. 4. The vehicle driving control system according to claim 3, wherein when the clutch is released by the driver before deceleration and stop by the ACC function, and the vehicle is restarted from a state stopped by the ACC function by reflecting a torque request from the ACC controller in control of engine output at a ratio corresponding to a clutch engagement rate, and when there is no preceding vehicle ahead of the vehicle, the ACC controller is configured to output a torque request higher than that when the vehicle is driving.

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