Vehicle control device

Abstract

To provide a vehicle control device advantageous for smoothing gear shifting operation while an AMT vehicle travels with ACC in execution.SOLUTION: A vehicle control device comprises: an AMT controller (40) which performs gear stage shifting operation of a gear shifting mechanism through controlling a gear shifting actuator and a clutch actuator in accordance with a vehicle speed and an engine rotation speed; an engine controller (20) which controls an engine in accordance with demand torque; and an ACC controller (10) which causes a vehicle to travel at a set speed when no vehicle is traveling ahead thereof or makes acceleration and deceleration requests so that the vehicle performs follow-up travel with a set inter-vehicle time maintained when another vehicle is traveling ahead thereof. The vehicle control device is adapted to execute control to increase demand torque (Th) at a time (tb) when a clutch is started to be engaged after gear stage shifting with demand torque (Tf) at a time (ta) when the gear stage shifting operation is started as a start value in a case where gear stage shifting operation is started while the ACC controller makes a request.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device, and more particularly to a vehicle control device equipped with an AMT type automatic transmission. [Background technology]

[0002] An automated manual transmission (AMT) type automatic transmission is known, which is equipped with a clutch that transmits engine output to a transmission mechanism and automatically performs gear shifting and clutch operation (see, for example, Patent Document 1). Such automatic transmissions have the advantages of high power transmission efficiency and excellent fuel economy.

[0003] On the other hand, systems that have been put into practical use include ACC (adaptive cruise control), which drives at a constant speed when there is no preceding vehicle in the vehicle's lane, and follows the preceding vehicle while maintaining a set intervehicle time when there is a preceding vehicle in the vehicle's lane traveling at less than the set speed, and LKA (lane keeping assist), which recognizes the vehicle's lane and provides automatic steering or steering assistance to keep the vehicle within the lane.In addition, ADAS (advanced driver assistance systems) that combine the ACC function (longitudinal control) and the LKA function (lateral control) are also being developed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6245109 Summary of the Invention [Problem to be solved by the invention]

[0005] In a vehicle equipped with an AMT automatic transmission, when the vehicle accelerates or decelerates in response to an acceleration or deceleration request from the ACC controller during ACC driving, the vehicle transitions to a gear change operation when the vehicle's driving state reaches a gear change point. When the transition to a gear change operation occurs, the AMT controller controls the clutch actuator and gear change actuator to release the clutch, change the gear position, and engage the clutch.

[0006] At this time, the AMT controller controls the clutch engagement rate to increase from zero to full engagement at a given engagement rate, in order to suppress shock when the clutch is engaged. However, because the acceleration request from the ACC controller continues even during the gear shift operation, there is a tendency for the engine to rev up due to the torque request corresponding to the increased acceleration request before the engagement rate increases to a level at which torque can be transmitted.

[0007] The present invention has been made in consideration of the above-described circumstances, and its purpose is to provide a vehicle control device that is advantageous in smoothing gear shifting operations during ACC driving in an AMT vehicle. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides: a clutch that transmits engine output to a transmission mechanism; a clutch actuator that engages and disengages the clutch; a speed change actuator that changes the gear stage of the speed change mechanism; an AMT controller that controls the shift actuator and the clutch actuator in accordance with a vehicle speed and an engine rotation speed to change the gear position of the shift mechanism; an engine controller that controls the engine in accordance with a required torque; an ACC controller that drives the vehicle at a set vehicle speed when there is no preceding vehicle in the vehicle's lane, and issues an acceleration / deceleration request to the preceding vehicle in order to follow the preceding vehicle while maintaining a set inter-vehicle time when there is a preceding vehicle in the vehicle's lane; A vehicle control device comprising: The gear stage change operation by the AMT controller includes clutch release by the clutch actuator, gear stage change by the shift actuator, and clutch engagement by the clutch actuator, If a gear stage change operation is initiated by the AMT controller during a request from the ACC controller, the system is configured to execute control to increase the required torque, with the required torque at the start of the gear stage change operation as a starting value, at the start of clutch engagement after the gear stage change. is located. [Effects of the Invention]

[0009] With the above-described configuration, the vehicle control device of the present invention maintains the required torque at the start of the gear shift operation (just before the clutch is released) even if the target torque for ACC driving increases during a gear stage change operation by the AMT controller, and when the clutch begins to engage, the required torque is increased using the maintained required torque as a starting value, thereby providing the advantage of suppressing the deviation between the required torque and the actual torque and suppressing the tendency for the engine to rev up due to a high engine torque relative to the clutch engagement rate. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a vehicle cruise control system. [Figure 2] 4 is a time chart showing a required torque and an actual torque during a gear shift operation. [Figure 3] 3 is a flowchart showing a travel control according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, a vehicle 1 includes an internal combustion engine 2 and an automatic transmission 4 via a clutch 3 in a torque transmission path from the engine 2 to drive wheels (6).

[0012] The clutch 3 is provided with a clutch actuator (not shown) that performs the engagement / disengagement operation, and the engagement rate and engagement / disengagement speed of the clutch 3 can be controlled by controlling the operating stroke and operating speed of the clutch actuator.

[0013] For example, the clutch 3 includes a clutch disc that is spline-engaged to the input shaft of the automatic transmission 4 so as to be axially slidable but non-rotatable, and a clutch spring (diaphragm spring) that biases the clutch disc via a pressure plate. When the clutch actuator is in an inoperative state, the clutch disc is pressed against a flywheel connected to the crankshaft of the engine 2 by the bias of the clutch spring, and power from the engine 2 can be transmitted from the crankshaft to the automatic transmission 4.

[0014] When the clutch actuator operates, the release bearing is pressed via the clutch lever in accordance with the stroke, causing the clutch disc to move away from the flywheel against the bias of the clutch spring, thereby cutting off the transmission of power from the engine 2. Also, the clutch 3 can be placed in a half-clutch state in which the power of the engine 2 is partially transmitted in accordance with the contact pressure (engagement rate) provided by the operating stroke of the clutch actuator.

[0015] Furthermore, by controlling the operating speed of the clutch actuator, it is possible to control the engagement and release speeds of the clutch 3. For example, when a hydraulic actuator is used as the clutch actuator, it is possible to control the operating speed of the hydraulic actuator by controlling the flow rate of hydraulic oil supplied to the hydraulic actuator, and it is also possible to control the engagement rate provided by any stroke of the hydraulic actuator by maintaining hydraulic pressure at that stroke.

[0016] The automatic transmission 4 is configured as an AMT type automatic transmission having an MT type shifting mechanism, for example, a parallel gear type shifting mechanism with a constant mesh synchromesh, and a shift actuator that performs gear stage operation, and is equipped with an AMT controller 40 that performs shifting operations according to the driving conditions of the vehicle 1.

[0017] The gear change actuator includes a select actuator that switches between P / R / N / D ranges and high / low gears according to the operating position of a select lever (not shown), and a shift actuator that performs shift operations, and works in conjunction with the clutch actuator to perform gear changes including clutch release, gear change, and clutch engagement. Note that hydraulic actuators are used as the select actuator and shift actuator, and an electric pump that supplies hydraulic pressure to them as well as the clutch actuator, a hydraulic circuit, an accumulator, a solenoid valve, and other components are mounted as a unit.

[0018] The vehicle 1 is equipped with an engine controller 20 that controls the output of the engine 2 in accordance with a throttle opening (torque request) given by operating an accelerator pedal (not shown) and acceleration / deceleration commands from an ACC controller 10 (described later). The AMT controller 40, through cooperative control with the engine controller 20, executes engine control linked to the clutch release / engagement operation in the above-mentioned gear shift operation.

[0019] For example, when the D range is selected, if the AMT controller 40 determines that a gear change (upshift / downshift) is necessary due to an acceleration request / deceleration request or a change in road gradient while driving in a gear position determined by driving conditions such as vehicle speed, engine speed, and torque (driving resistance), the AMT controller 40 will change the gear position (upshift / downshift) by setting the torque request to zero at the same time as the clutch is released, and will make a torque request at the same time as the clutch begins to engage, and the driving torque will be transmitted to the automatic transmission 4 in accordance with the engagement rate of the clutch 3, and once the series of gear change operations is completed, the engine will return to control of the engine by the engine controller 20.

[0020] The vehicle 1 is equipped with a brake system that constitutes an ABS / vehicle behavior stabilization device, which includes a brake controller 30 that can individually control the braking forces of brakes 36 for the left and right front wheels 6 and brakes 37 for the left and right rear wheels 7 in response to brake pedal operation (not shown) or a deceleration command from an ACC controller 10 (described later), a brake actuator (hydraulic actuator) (not shown), wheel speed sensors 36 for the left and right front wheels 6, and wheel speed sensors 37 for the left and right rear wheels 7.

[0021] The vehicle 1 having the above-described basic configuration is equipped with preceding vehicle detection means 11, which constitutes an ACC system together with the ACC controller 10. The preceding vehicle detection means 11 can be one or more detection means, such as millimeter-wave radar, monocular camera, stereo camera, LIDAR, etc., that have the function of detecting the presence of preceding vehicles or objects (obstacles, structures) ahead of the host vehicle and that can measure the relative distance (relative inter-vehicle time) between the host vehicle and the preceding vehicle or obstacle.

[0022] The ACC controller 10 is configured to issue acceleration / deceleration commands to the engine controller 20 and brake controller 30 in place of the driver's accelerator / brake operation based on the detection information from the preceding vehicle detection means 11 and the vehicle speed calculated from the detection values ​​of the wheel speed sensors 36, 37, and to execute adaptive cruise control (constant speed driving / follow-up driving control / deceleration / stop / restart control) compatible with all vehicle speed ranges.

[0023] That is, the brake controller 30 (brake controller) that receives a deceleration command from the ACC controller 10 issues a brake request (hydraulic pressure request) to the brake actuator and controls the braking force of the brakes 36, 37, thereby controlling the vehicle speed. Also, the engine controller 20 that receives an acceleration / deceleration command from the ACC controller 10 issues a torque request to the engine 2 and controls the actuator output (throttle opening) to control the torque of the engine 2 and thus the vehicle speed.

[0024] Through the above control by the ACC controller 10, the vehicle 1 maintains a set vehicle speed and travels at a constant speed when there is no preceding vehicle, and when it catches up with the preceding vehicle, it follows the preceding vehicle while maintaining a distance according to a predetermined inter-vehicle time (time gear up = inter-vehicle distance / own vehicle speed) in accordance with the speed of the preceding vehicle. Furthermore, if the preceding vehicle decelerates to a stop while following, or if the vehicle 1 catches up with a preceding vehicle that is decelerating to a stop, it decelerates to a stop while maintaining a predetermined inter-vehicle distance, and if the preceding vehicle starts moving within the predetermined time, it restarts to match it and continues following.

[0025] The engine controller 20, AMT controller 40, brake controller 30, and ACC controller 10 described above are all configured with a microcomputer (MCU) consisting of a ROM for storing control programs and setting data, a RAM for temporarily storing the results of arithmetic processing, a CPU for performing arithmetic processing, a communication I / F, etc., and are connected via an in-vehicle network (e.g., CAN) to be able to communicate with a group of sensors including a preceding vehicle detection means 11 and an inclination sensor 12.

[0026] (Gear shift control during acceleration using ACC driving) As already mentioned, the AMT controller 40 controls the clutch engagement rate to increase from zero to full engagement at a given engagement speed, in order to suppress shock when the clutch is engaged. However, since the acceleration request from the ACC controller 10 continues even during the gear shift operation, if a torque request corresponding to the increased acceleration request is made before the engagement rate at which torque can be transmitted is reached, there is a risk that the engine will rev up.

[0027] For example, in FIG. 2, when the vehicle 1 is accelerating due to an acceleration request from the ACC controller 10 and the vehicle's running state reaches the shift point (ta), torque control of the engine 2 is transferred to the AMT controller 40, which releases the clutch 3 and reduces the torque of the engine 2 with a predetermined low requested torque (for example, 0 Nm), and changes the gear (in this case, shifts up) when the actual torque Tk(t) becomes zero due to clutch disengagement.

[0028] Next, at point (tb), engagement of the clutch 3 begins and the torque of the engine 2 is increased, and the actual torque also increases as the clutch engagement rate increases. At this time, if the AMT controller 40 increases the torque using the target acceleration-based required torque Tg(t) of the ACC controller 10 as a control target until torque control of the engine 2 returns to the ACC controller 10 at point (td), a tendency for the engine to rev up occurs due to the high engine torque relative to the clutch engagement rate α.

[0029] Therefore, in the control according to the present invention, the ACC controller 10 holds the required torque Tf(t) at point (ta) when the AMT controller 40 starts the gear change operation (when the clutch starts to be released), and after the gear change, at point (tb) when the clutch starts to be engaged, executes control to increase the required torque as follows, using the held required torque Tf(t) as the starting value.

[0030] That is, the ACC controller 10 calculates the target vehicle speed and internal target acceleration for maintaining the set vehicle speed or set inter-vehicle time, and by allocating the rising curve of the required torque Tg(t) based on this internal target acceleration from point (ta) to point (td) where normal control is returned to, to the point (tb) where clutch engagement begins after a gear change to point (td) using the following equation 1, the rising curve of the required torque Th(t) according to the clutch engagement rate α is obtained. (Formula 1) Th(t)=α*Tg(t)+(1−α)*Tf(t)

[0031] The AMT controller 40 uses the required torque Tf(t) held at the start of the gear change operation as the starting value and increases the torque with the required torque Th(t) corresponding to the clutch engagement rate α as the control target as described above. This suppresses the deviation between the required torque Th(t) and the actual torque Tk(t), which is advantageous in suppressing the tendency of the engine 2 to rev up while the clutch is engaged, particularly before the point (tc) where the engagement rate becomes such that torque can be transmitted.

[0032] FIG. 3 shows the flow of the gear change control during ACC driving as described above. When the ACC function is activated while the vehicle 1 is traveling (step 100), the ACC controller 10 requests the engine controller 20 to accelerate or decelerate in order to maintain the set vehicle speed or set inter-vehicle time, and the engine controller 20 controls the engine 2 with the required torque according to the vehicle speed, etc. (step 101).

[0033] When the running state of the vehicle 1 reaches a gear change point and the AMT controller 40 starts a gear change operation (upshift) (step 102; YES), the AMT controller 40 releases the clutch 3 (step 103). After this, the torque control during the gear change operation is taken over by the AMT controller 40, and although the actual torque decreases, the ACC controller 10 maintains the required torque (Tf) at the time of clutch release (step 104).

[0034] When the AMT controller 40 completes the upshift operation and starts clutch engagement (step 105; YES), the ACC controller 10 increases the required torque Th(t) according to the clutch engagement rate α, using the required torque (Tf) at clutch off as a starting value (step 106).

[0035] The AMT controller 40 controls the engine using the required torque Th(t) as the target torque, and as the clutch engagement rate α increases, the actual torque also increases. When the clutch engagement ends (step 107; YES), the AMT controller 40 returns to ACC driving based on the acceleration / deceleration request of the ACC controller 10 (step 108).

[0036] In the above embodiment, the rising curve of the required torque Tg(t) based on the internal target acceleration of the ACC controller 10 is assigned after a gear change to obtain a rising curve of the required torque Th(t) according to the clutch engagement rate α. However, in another embodiment, a rev-up limit map (look-up table) that specifies the engine rev-up limit based on the clutch engagement rate α and the required torque is stored in advance in the AMT controller 40, and after a gear change during ACC driving, the rev-up limit map is referenced to limit the required torque from the start of clutch engagement until full engagement, and the required torque can be increased within the rev-up limit.

[0037] Furthermore, in the above embodiment, the case of an upshift during acceleration due to ACC driving has been described. However, in the case of a downshift during deceleration due to ACC driving, the torque required by the ACC controller 10 based on the target deceleration is lower than the torque required at the start of the gear change operation, so there is no tendency for the engine to rev up, and the torque drop acts as engine braking, so the torque required by the ACC controller 10 based on the target deceleration may be maintained.

[0038] On the other hand, when downshifting during deceleration in ACC driving, just as when upshifting, control can be performed so that the required torque at the start of the gear change operation is set as the starting value when the clutch engagement begins, thereby accelerating the rise of the torque and suppressing the tendency for excessive engine braking due to a torque drop based on the target deceleration during downshifting, thereby ensuring smooth deceleration driving.

[0039] Although the 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 various modifications and alterations are possible based on the technical concept of the present invention. [Explanation of symbols]

[0040] 1 vehicle 2 engines 3. Clutch 4. Automatic transmission 10 ACC controller 11. Means for detecting preceding vehicles 12 Inclination sensor 16,17 Wheel speed sensor 20 Engine Controller 30 Brake control device 36,37 Brakes 40 AMT Controller

Claims

1. a clutch that transmits engine output to a transmission mechanism; a clutch actuator that engages and disengages the clutch; a speed change actuator that changes the gear stage of the speed change mechanism; an AMT controller that controls the shift actuator and the clutch actuator in accordance with a vehicle speed and an engine rotation speed to change the gear position of the shift mechanism; an engine controller that controls the engine in accordance with a required torque; an ACC controller that drives the vehicle at a set vehicle speed when there is no preceding vehicle in the vehicle's driving lane, and that issues an acceleration / deceleration request to the preceding vehicle in order to follow the preceding vehicle while maintaining a set inter-vehicle time when there is a preceding vehicle in the vehicle's driving lane; A vehicle control device comprising: The gear stage change operation by the AMT controller includes clutch release by the clutch actuator, gear stage change by the shift actuator, and clutch engagement by the clutch actuator, A vehicle control device characterized in that, when a gear stage change operation is started by the AMT controller during a request from the ACC controller, control is executed to increase the required torque, with the required torque immediately before clutch release at the start of the gear stage change operation as a starting value, at the start of clutch engagement after the gear stage change.

2. 2. The vehicle control device according to claim 1, wherein the control for increasing the required torque from the starting value increases the required torque in accordance with an engagement rate of the clutch.

3. 3. The vehicle control device according to claim 1, wherein when the gear position change operation is started, the ACC controller holds the required torque at the start, and when the clutch engagement starts after the gear position change, the held required torque is set as a start value.

4. 4. The vehicle control device according to claim 1, wherein when the gear stage change operation is started, the AMT controller reduces torque from the start of the gear stage change operation regardless of the torque value required by the ACC controller, and increases torque with the torque value required by the ACC controller as a target when the clutch engagement starts after the gear stage change.

5. 5. The vehicle control device according to claim 1, wherein the control for increasing the required torque from the start value is performed in accordance with an increase curve obtained by allocating a required torque increase curve based on an internal target acceleration of the ACC controller from the start to the end of a gear stage change operation by the AMT controller to the start to the end of clutch engagement after the gear stage change.

6. 3. The vehicle control device according to claim 1, further comprising a map that specifies a limit of engine revving based on an engagement rate of the clutch and the required torque, and the required torque is increased within the limit of engine revving by referring to the map until the clutch is fully engaged.

7. 7. The vehicle control device according to claim 1, wherein the control for increasing the required torque from a starting value that is the required torque at the start of the gear position change operation is executed during an upshift during an acceleration request from the ACC controller.

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