JP5246180B2 - Vehicle control system - Google Patents

Description

  The present invention relates to a vehicle control system.

  Conventionally, a technique for automatically stopping and resuming operation of a power source according to a predetermined condition is known. For example, Patent Document 1 discloses that predetermined stop control including control for stopping the supply of fuel to the internal combustion engine is performed when a predetermined stop condition is satisfied, and the internal combustion engine is operated when a predetermined start condition is satisfied. A technique of a stop / start control device for an internal combustion engine that executes start control including control for restarting fuel supply to the engine is disclosed.

JP 2003-65104 A

  Here, if the starting condition, which is a condition for determining the resumption timing of the operation of the power source, is not set appropriately, fuel consumption may be reduced.

  An object of the present invention is to provide a vehicle control system capable of improving fuel consumption when the operation of a power source is automatically stopped and restarted.

  The vehicle control system according to the present invention includes a load changing unit capable of changing a load magnitude of the power source acting on the drive wheel when the power source of the vehicle is rotationally driven by the drive wheel of the vehicle, and the load And a control device for controlling the changing means, wherein the control device is capable of executing power source stop control for stopping generation of power by the power source when the vehicle is running, and the control device is configured to stop the power source stop. While the control is executed and the power source is rotationally driven by the driving wheel, the end of the braking operation by the driver is detected, and after the end of the braking operation is detected, the acceleration operation by the driver is started. When detected, if the elapsed time from the end of the braking operation to the start of the acceleration operation is equal to or longer than a predetermined time, the generation of power by the power source is not resumed. , Characterized in that to reduce the magnitude of the load by the load changing means.

  In the vehicle control system, the end of the braking operation is detected based on an operation amount of the driver with respect to the operation member of the vehicle, and the predetermined time corresponds to the end of the braking operation by the driver. The predetermined amount of time when the change rate is large is longer than the predetermined time when the change rate is small. Is preferred.

  In the vehicle control system, the load changing unit changes a degree of transmission of power between the power source and the driving wheel, and the control device uses the load changing unit to change the degree of transmission of the power. It is preferable to reduce the magnitude of the load by lowering.

  In the vehicle control system, the load changing unit can switch between a state where the power is transmitted and a state where the power is not transmitted in a power transmission path between the power source and the drive wheels. However, it is preferable that the control device reduce the magnitude of the load by switching to a state in which the power is not transmitted in the transmission path by the load changing unit.

  In the vehicle control system, the end of the braking operation is detected based on an operation amount of the driver with respect to the operation member of the vehicle, and the control device responds to the end of the braking operation by the driver. When the change amount of the operation amount when changing the operation amount of the operation member up to the operation amount to be performed is equal to or higher than a predetermined speed, the transmission path may include the It is preferable to maintain a state in which power is transmitted.

  The vehicle control system according to the present invention includes a load changing unit capable of changing a load magnitude of the power source acting on the drive wheel when the power source of the vehicle is rotationally driven by the drive wheel of the vehicle, and the load And a control device for controlling the changing means, wherein the control device is capable of executing power source stop control for stopping generation of power by the power source when the vehicle is running, and the control device is configured to stop the power source stop. When the start of the acceleration operation by the driver is detected while the control is executed and the power source is rotationally driven by the driving wheel, the vehicle speed of the vehicle finally changed from the acceleration to the deceleration. When the vehicle speed is lower than a predetermined reduction amount from the vehicle speed at the time, the load changing means does not restart the generation of power by the power source, and the load changing means Characterized in that reducing the size.

  In the vehicle control system according to the present invention, the end of the braking operation by the driver is detected while the power source stop control is being executed and the power source is rotationally driven by the drive wheels, and after the end of the braking operation is detected. When the start of the acceleration operation by the driver is detected and the elapsed time from the end of the braking operation to the start of the acceleration operation is equal to or longer than a predetermined time, the generation of power by the power source is not resumed. The load acting on the drive wheel is reduced by the load changing means. According to the vehicle control system according to the present invention, in the situation where the elapsed time is long and the acceleration delay is unlikely to occur such as the driver does not want quick acceleration, without restarting the generation of power by the power source, It is possible to adjust the deceleration according to the acceleration operation of the driver, and there is an effect that the fuel consumption can be improved.

FIG. 1 is a flowchart showing the operation of the first embodiment of the vehicle control system. FIG. 2 is another flowchart showing the operation of the vehicle control system of the embodiment. FIG. 3 is a diagram illustrating a vehicle to which the vehicle control system of the embodiment is applied. FIG. 4 is a diagram for explaining the relationship between the accelerator opening and the vehicle G according to the embodiment. FIG. 5 is a diagram illustrating a predetermined time according to the modification. FIG. 6 is a diagram for describing vehicle control according to the second embodiment.

  Hereinafter, an embodiment of a vehicle control system according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

(First embodiment)
The first embodiment will be described with reference to FIGS. 1 to 4. The present embodiment relates to a vehicle control system. FIG. 1 is a flowchart showing the operation of the first embodiment of the vehicle control system according to the present invention, FIG. 2 is another flowchart showing the operation of the vehicle control system of the present embodiment, and FIG. 3 is the vehicle of the present embodiment. It is a figure which shows the vehicle to which the control system was applied.

  In the vehicle control system 1-1 of the present embodiment, when the driver performs an operation to reduce the deceleration by stepping on the accelerator from the state where the fuel is cut by the accelerator fully closed and the engine brake is effective, the engine (FIG. 3 (see reference numeral 11 in FIG. 3) and the drive wheel (see reference numeral 16 in FIG. 3) to release the clutch (see reference numeral 40 in FIG. 3) to bring the drive wheel 16 into a free-run state and stop the engine 11. Means to improve fuel efficiency by continuing fuel cut. However, once the clutch 40 is released, a delay occurs when it is desired to accelerate. Therefore, the clutch cannot be released every time the accelerator is depressed.

  In the present embodiment, as will be described below, whether or not to release the clutch 40 when the accelerator is ON is determined by the elapsed time from the brake OFF to the accelerator ON. This elapsed time is considered to reflect the driver's intention, such as whether the driver wants quick acceleration or is trying to fine-tune the driving force. In a situation where the elapsed time from the brake OFF to the accelerator ON is long and the driver does not want quick acceleration, the vehicle control system 1-1 releases the clutch 40 and puts the drive wheels 16 into a free-run state. The engine 11 is stopped. Thereby, according to the vehicle control system 1-1 of this embodiment, a fuel consumption can be improved.

  As shown in FIG. 3, the vehicle 1 is provided with an engine 11 as a power source of the vehicle 1. An automatic transmission 13 having a torque converter 12 is connected to the engine 11. The driving force of the engine 11 is input to the automatic transmission 13 via the torque converter 12 and transmitted to the driving wheels 16 via the differential gear 14 and the drive shaft 15. The automatic transmission 13 of the present embodiment is a stepped automatic transmission (AT), but another automatic transmission (CVT or the like) may be mounted instead. The automatic transmission 13 and the differential gear 14 are connected via a clutch 40.

  The clutch 40 can transmit power between the automatic transmission 13 and the differential gear 14 and can change the degree of power transmission. The clutch 40 is, for example, a friction engagement type clutch device, and is engaged or released by hydraulic pressure. The clutch 40 is controlled by a clutch hydraulic control device 41. The clutch hydraulic pressure control device 41 controls an engagement hydraulic pressure that is a hydraulic pressure supplied to the clutch 40, and is controlled by a control command of the ECU 20 described later. The clutch 40 is in an open state in which power cannot be transmitted between the engine 11 and the drive wheels 16 due to the hydraulic pressure supplied by the clutch hydraulic control device 41, and is engaged to transmit power between the engine 11 and the drive wheels 16. Switch to the state. In other words, the clutch 40 can be switched between a state in which power is transmitted in the power transmission path between the engine 11 and the drive wheels 16 and a state in which power is not transmitted in the transmission path.

  Furthermore, the clutch 40 can be controlled to a fully engaged state and a semi-engaged state by the engagement hydraulic pressure. In the half-engaged state, the clutch 40 engages the power in a slip state in which the engine 11 side and the drive wheel 16 side rotate relative to each other, and the slip amount (degree of power transmission) changes depending on the engagement hydraulic pressure. The clutch 40 functions as a load changing means capable of changing the magnitude of the load applied by the engine 11 acting on the drive wheel 16 when the engine 11 is rotationally driven by the drive wheel 16 by changing the degree of power transmission. can do.

  The arrangement of the clutch 40 is not limited between the automatic transmission 13 and the differential gear 14 as long as the power transmission path between the engine 11 and the drive wheels 16 is connected or disconnected. For example, the clutch 40 may be provided between the engine 11 and the automatic transmission 13 or in the automatic transmission 13. Further, the clutch 40 is not limited to a clutch whose engagement state (engagement / release switching, power transmission degree) is controlled by hydraulic pressure, and may be any clutch whose engagement state is controlled by a control device.

  The brake device 18 is controlled by the brake hydraulic pressure control device 19 to brake the vehicle. In the automatic transmission 13, the gear ratio is automatically controlled by the A / T hydraulic control device 17 in accordance with the driving state of the vehicle. The vehicle 1 is provided with an electronic control unit (ECU) 20 that controls the engine 11, the automatic transmission 13, the brake device 18, the clutch hydraulic pressure control device 41, and the like. The ECU 20 performs comprehensive control of the engine 11, the automatic transmission 13 (A / T hydraulic control device 17), the brake device 18 (brake hydraulic control device 19), and the clutch hydraulic control device 41. The ECU 20 performs fuel control, valve control, EGR control, throttle control, and the like as control of the engine 11. The ECU 20 of this embodiment functions as a control device that controls the clutch hydraulic pressure control device 41 and the clutch 40 as load changing means. The vehicle control system 1-1 according to the present embodiment includes an ECU 20, a clutch 40, and a clutch hydraulic pressure control device 41.

  The vehicle 1 is provided with an accelerator position sensor 21 for detecting an operation amount (accelerator opening) of an accelerator pedal. A signal indicating the accelerator opening detected by the accelerator position sensor 21 is output to the ECU 20. A throttle control valve 23 provided in the intake pipe 22 of the engine 11 can be opened and closed by a throttle actuator 24. The ECU 20 can control the throttle opening of the throttle control valve 23 by the throttle actuator 24 regardless of the accelerator opening. The vehicle 1 is provided with a throttle opening sensor 27 that detects the throttle control valve 23 in a fully closed state (idle state) and the throttle opening. Signals indicating the idle state and the throttle opening detected by the throttle opening sensor 27 are output to the ECU 20.

  The engine 11 is provided with an engine speed sensor 28 that detects the engine speed (engine speed). The vehicle speed sensor 29 detects the vehicle speed of the vehicle. The shift position sensor 30 detects the position (shift position) of the shift lever operated by the driver. The brake operation amount sensor 32 detects an operation amount related to the brake device 18, and detects an operation amount by a driver for an operation member (for example, a brake pedal) (not shown) for a braking operation provided in the vehicle 1. . Based on the operation amount detected by the brake operation amount sensor 32, the ECU 20 can detect the start / end of the braking operation, the variable acceleration of the operation amount when the braking operation is ended, and the like. The clutch input shaft rotational speed sensor 33 detects the rotational speed of the input shaft of the clutch 40 (the shaft connected to the automatic transmission 13). The clutch output shaft rotational speed sensor 34 detects the rotational speed of the output shaft of the clutch 40 (the shaft connected to the differential gear 14). A signal indicating the detection result of each sensor 28, 29, 30, 32, 33, 34 is output to the ECU 20. In addition, the ECU 20 receives other signals such as various sensors for controlling the engine 11, a sensor for detecting the rotational speed of the input shaft of the automatic transmission 13, and a sensor for detecting engine torque.

  The ECU 20 has a shift map, determines the gear position of the automatic transmission 13 based on the throttle opening, vehicle speed, and the like, and sets the A / T hydraulic control device 17 so as to establish the determined gear position. Can be controlled.

  The ECU 20 starts fuel cut control for stopping the supply of fuel to the engine 11 when a predetermined fuel cut start condition is satisfied. The fuel cut control is power source stop control for stopping the generation of power by the engine 11 when the vehicle 1 is traveling. The fuel cut start condition includes, for example, a condition that the accelerator is off and a condition that the engine speed is equal to or lower than a predetermined speed. When the fuel cut control is executed, combustion is not performed in the cylinder, and the generation of power by the engine 11 is stopped. As a result, the engine 11 is driven by the drive wheels 16 via the automatic transmission 13, the differential gear 14, and the drive shaft 15. That is, during execution of fuel cut control, the engine 11 becomes a load on the drive wheels 16 and causes the vehicle 1 to generate deceleration. At least when the fuel cut control is started, the clutch 40 is in an engaged state (for example, a fully engaged state).

  The ECU 20 controls to release the clutch 40 (hereinafter simply referred to as “clutch release control”) when the accelerator depression operation (accelerator ON) from the fully closed state of the accelerator by the driver is detected during the fuel cut control. Can be executed. When the clutch release control is performed, the transmission of power between the engine 11 and the drive wheels 16 becomes impossible, and the engine 11 does not act as a load on the drive wheels 16. As a result, the drive wheels 16 are in a free-running state that rotates in a state where no load is applied by the engine 11, and the deceleration of the vehicle 1 is reduced.

  The driver may need an engine brake during the fuel cut, or may need only coasting without the engine brake. The accelerator ON operation is performed during the fuel cut control, for example, when the driver desires coasting. As described above, if the driver wants coasting or only wants to reduce the deceleration (to reduce the engine braking force), driving the engine 11 may cause a reduction in fuel consumption. . If the clutch disengagement control is executed instead of operating the engine 11, the deceleration can be reduced without restarting the supply of fuel to the engine 11 (generation of power by the engine 11). . Therefore, fuel efficiency can be improved while responding to the driver's request for deceleration adjustment.

  However, the driver may desire acceleration when operating the accelerator ON during the fuel cut control. Once the clutch 40 is released, a delay occurs when it is desired to accelerate. Since it takes time until the start of the engine 11 and the engagement of the clutch 40 are completed after the clutch 40 is released, the start of acceleration is delayed. Therefore, when the driver operates the accelerator ON, it is desirable to be able to appropriately determine whether the driver desires coasting or acceleration.

  In the present embodiment, the ECU 20 detects the brake OFF (the end of the braking operation by the driver) while the fuel cut control is being executed and the engine 11 is rotationally driven by the drive wheels 16, and the brake OFF is detected. When accelerator ON (start of acceleration operation) is detected later, either coasting or acceleration is selected according to the elapsed time Ti from brake OFF to accelerator ON. Specifically, the ECU 20 starts the engine 11 without releasing the clutch 40 when the elapsed time Ti is less than a predetermined time T0. When the time from the brake OFF to the accelerator ON is short, it is considered that the driver desires a quick acceleration. Therefore, the fuel is immediately put into the engine 11 for the accelerator ON to fire and prepare for the acceleration. On the other hand, when the elapsed time Ti is equal to or longer than the predetermined time T0, the vehicle 1 is coasted by clutch release control for releasing the clutch 40 without resuming generation of power by the engine 11. That is, the load of the engine 11 acting on the drive wheels 16 is reduced by the clutch 40 that is the load changing means. This is because it is considered that the driver desires coasting when the time from the brake OFF to the accelerator ON is long. In addition, even if the driver wants acceleration, it is considered that he does not want quick acceleration. Therefore, when the accelerator is further depressed after the accelerator is turned on, the engine 11 is started and the clutch 40 is engaged. However, the acceleration delay is unlikely to occur.

  The operation of this embodiment will be described with reference to FIGS. FIG. 1 is a flowchart for determining whether or not to shift to clutch release control, and FIG. 2 is a flowchart for determining the end of clutch release control. The control flow shown in FIG. 1 is executed during execution of fuel cut control. For example, when the brake OFF is detected, the control flow is repeatedly executed at a predetermined interval.

  In step S1, the ECU 20 determines whether or not the accelerator has changed from the accelerator OFF to the accelerator ON. Based on the signal indicating the detection result of the accelerator position sensor 21, the ECU 20 determines whether or not the accelerator opening has changed from a predetermined opening indicating the fully closed state of the accelerator to an opening determined to be accelerator ON. judge. As a result of the determination, if it is determined that the accelerator has changed from the accelerator OFF to the accelerator ON (step S1-Y), the process proceeds to step S2, and if not (step S1-N), the process returns.

  In step S2, the ECU 20 determines whether or not a predetermined time has elapsed since the brake was turned off. The ECU 20 makes this determination based on a signal indicating the detection result of the accelerator position sensor 21 and a signal indicating the detection result of the brake operation amount sensor 32. The ECU 20 determines the time at which the brake operation amount detected by the brake operation amount sensor 32 has changed from a value indicating brake ON to a predetermined value determined as brake OFF (an operation amount corresponding to the end of the braking operation). Set the brake OFF time. Further, the ECU 20 sets the time at which the change to the accelerator ON in step S1 is detected as the accelerator ON time. If the elapsed time from the brake OFF time to the accelerator ON time is equal to or longer than a predetermined time, an affirmative determination is made in step S2. As a result of the determination in step S2, if it is determined that the predetermined time has elapsed since the brake is turned off (step S2-Y), the process proceeds to step S3, and if not (step S2-N), the process returns. .

  In step S3, clutch release control is executed by the ECU 20. The ECU 20 controls the clutch hydraulic pressure control device 41 so that the hydraulic pressure supplied to the clutch 40 is the hydraulic pressure at which the clutch 40 is released, so that power is transmitted in the power transmission path between the engine 11 and the drive wheels 16. Switch to no state. As a result, power transmission between the engine 11 and the drive wheels 16 becomes impossible, and the engine 11 stops rotating. Further, the load of the engine 11 acting on the drive wheel 16 is reduced. When step S3 is executed, the process returns.

  The control flow shown in FIG. 2 is executed while the clutch release control is being executed. For example, the control flow is repeatedly executed at predetermined intervals.

  First, in step S11, the ECU 20 determines whether or not the clutch 40 is being released. The ECU 20 can make the determination in step S11 based on the detection results of the clutch input shaft rotational speed sensor 33 and the clutch output shaft rotational speed sensor 34, for example. For example, the ECU 20 opens the clutch 40 when the rotation speed of the input shaft of the clutch 40 is a value indicating the rotation stop of the input shaft, and the rotation speed of the output shaft of the clutch 40 is a value indicating the rotation state of the output shaft. It is determined that it is in the middle. As a result of the determination in step S11, if it is determined that the clutch 40 is being disengaged (step S11-Y), the process proceeds to step S12, and if not (step S11-N), the process returns.

  In step S12, the ECU 20 determines whether or not the current accelerator opening detected by the accelerator position sensor 21 is less than a first predetermined value α. The first predetermined value α is a predetermined accelerator opening threshold value that determines whether or not the clutch 40 is engaged and the engine brake is applied. The first predetermined value α can be, for example, the accelerator opening at the boundary between the accelerator OFF and the accelerator ON. As a result of the determination in step S12, if it is determined that the accelerator opening is less than the first predetermined value α (step S12-Y), the process proceeds to step S13. If not (step S12-N), step S14 is performed. Proceed to

  In step S13, the clutch 20 is engaged by the ECU 20. The ECU 20 controls the clutch hydraulic pressure control device 41 so that the hydraulic pressure supplied to the clutch 40 is the hydraulic pressure at which the clutch 40 is engaged. As a result, the engine 11 and the drive wheels 16 can transmit power, and the engine 11 acts as a load on the drive wheels 16 and the engine brake is applied. When step S13 is executed, the process returns.

  In step S14, the ECU 20 determines whether or not the current accelerator opening detected by the accelerator position sensor 21 is larger than a second predetermined value β. The second predetermined value β is a predetermined accelerator opening threshold value for determining whether or not to start the engine 11. The second predetermined value β is an opening greater than or equal to the first predetermined value α. As a result of the determination in step S14, when it is determined that the accelerator opening is larger than the second predetermined value β (step S14-Y), the process proceeds to step S15, and otherwise (step S14-N). Returning, the clutch release control is continued.

  In step S <b> 15, the engine 20 is started and the clutch 40 is engaged by the ECU 20. The ECU 20 ends the fuel cut control, starts the engine 11, ends the clutch release control, and engages the clutch 40. When step S15 is executed, the process returns.

  FIG. 4 is a diagram for explaining the relationship between the accelerator opening and the vehicle G when the vehicle control of the present embodiment is performed. In FIG. 4, the horizontal axis represents the accelerator opening, and the vertical axis represents the longitudinal acceleration of the vehicle 1. FIG. 4 shows the relationship between the accelerator opening and the vehicle G at low vehicle speeds (low engine speed). Reference numeral 100 denotes a relationship between the accelerator opening when the vehicle control of the present embodiment is performed and the vehicle G, and reference numeral 101 denotes a relationship between the accelerator opening and the vehicle G when the free run by the clutch release control is not performed. An example is shown.

  Symbol G1 is the minimum value of the longitudinal acceleration generated in the vehicle 1 when the engine 11 is fired (the engine 11 generates power). Reference sign G2 represents the longitudinal acceleration of the vehicle 1 when the fuel cut control is performed and the clutch 40 is engaged. When the accelerator opening becomes the first predetermined value α by the driver's accelerator ON operation during the fuel cut control, when the engine 11 is started, the acceleration is greatly increased to the acceleration indicated by the symbol G2. On the other hand, in the present embodiment, at the first predetermined value α, the free-run state is set by clutch release control. Reference numeral 100a indicates the longitudinal acceleration of the vehicle 1 in the free-run state. The acceleration in the free-run state is smaller than the acceleration G2 during the fuel cut control, and is larger than the acceleration G1 during the firing. That is, the deceleration between the fuel cut control and the firing can be achieved by the clutch release control. Thereby, according to the vehicle control of the present embodiment, the driver can easily realize the desired deceleration by the accelerator operation.

  For example, if the fuel cut control is being executed and the brake is on and the deceleration is to be reduced, the brake is turned off (acceleration G2), and if the deceleration is to be further reduced, the accelerator is turned on to enter the free run state. (See reference numeral 100a). If the deceleration is still felt, the engine 11 is started when the accelerator is depressed, and the engine braking force is reduced (acceleration G1). The deceleration can be finely adjusted, and the drivability is improved because the step of the deceleration is small. Further, by utilizing the free-run state, the vehicle 1 can be driven without operating the engine 11 at the accelerator opening between the first predetermined value α and the second predetermined value β. Therefore, the fuel efficiency can be improved as compared with the case where the engine 11 is started with the accelerator opening of the first predetermined value α.

  In addition, when the driver desires acceleration (rapid acceleration) during execution of fuel cut control, the accelerator is turned on in a short time after the brake is turned off. In this case, in this embodiment, clutch release control is not performed, fuel is supplied and ignited, and the operation of the engine 11 is resumed. Therefore, it is possible to respond to the driver's acceleration request with high responsiveness.

  The power train to which the vehicle control system 1-1 of the present embodiment can be applied is not limited to the above-described one, and for example, another known power source may be mounted instead of the engine 11. . The vehicle 1 of the present embodiment may further include a motor. In this case, the motor may be disposed either before or after the automatic transmission 13 in the power transmission path or before the engine 11. The ECU 20 may be <engine control ECU × transmission control ECU>, <power train ECU>, <hybrid control ECU>, or the like.

  When the elapsed time from the brake OFF time to the accelerator ON time is equal to or longer than a predetermined time, the clutch 40 is kept engaged and the degree of power transmission is reduced instead of the clutch release control. You may make it make it. Even in this case, it is possible to reduce the magnitude of the load caused by the engine 11 acting on the drive wheels 16 and reduce the deceleration.

(First modification of the first embodiment)
A first modification of the first embodiment will be described with reference to FIG. In this modification, the difference from the above embodiment is that a predetermined time for determining whether or not to shift to clutch release control is variable according to the brake release speed.

  FIG. 5 is a diagram showing the predetermined time according to this modification, and shows the relationship between the change speed of the brake operation amount (brake release speed) in the brake OFF operation during fuel cut and the predetermined time. The brake release speed is a change rate of the operation amount when the driver changes the operation amount of the operation member to the operation amount corresponding to the end of the braking operation. When the brake release speed is low, it is considered that the driver's operation is delicately adjusting the driving force. For this reason, as shown in FIG. 5, the predetermined time is substantially constant and has a small value in the region where the brake release speed is small. It is considered that the driver is performing rough acceleration / deceleration as the brake release speed increases. For this reason, in the brake release speed region of a certain magnitude or more, the predetermined time increases as the brake speed increases. Further, as the brake release speed increases, the increment of the predetermined time with respect to the brake release speed increases. That is, the predetermined time when the brake release speed is high is longer than the predetermined time when the brake release speed is low.

  As a result, when the brake release speed is low, that is, when the brake pedal is slowly returned and the brake is turned off, the engine 11 is operated even if the elapsed time until the accelerator is turned on is relatively short thereafter. Instead, shift to clutch release control. In an operating environment where the brake release speed is high, that is, the acceleration / deceleration is severe, it is difficult to enter the coasting mode with the clutch 40 opened. In this way, when the driving force is finely adjusted by changing the ease of entering the coasting mode by the clutch release control according to the brake operation speed of the driver when the brake is OFF, While adjustment is easy and fuel efficiency improves, when acceleration / deceleration with good response is desired, it becomes difficult to enter the coasting mode, and acceleration delay is suppressed. Therefore, it is possible to achieve both improvement in drivability and fuel efficiency as much as possible.

(Second modification of the first embodiment)
A second modification of the first embodiment will be described. In the present modification, the difference from the first embodiment and the first modification is that clutch release control is prohibited when the brake release speed is high. When the brake release speed is equal to or higher than a predetermined release speed threshold (predetermined speed), the ECU 20 does not permit clutch release control even if the elapsed time from the brake OFF to the accelerator ON is longer than a predetermined time. . Thereby, the state in which power is transmitted in the power transmission path between the engine 11 and the drive wheels 16 is maintained. On the other hand, when the elapsed time from the brake OFF to the accelerator ON is equal to or longer than the predetermined time and the brake release speed does not exceed the release speed threshold, the ECU 20 permits the clutch release control. According to this modified example, in a driving environment where acceleration / deceleration is severe, it is possible to prevent the clutch 40 from opening and coasting.

  The predetermined time T0 may be constant or variable. For example, the predetermined time T0 may be changed according to the brake release speed as in the first modified example.

(Second Embodiment)
The second embodiment will be described with reference to FIG. In the second embodiment, members and components having the same functions as those described in the above embodiment are denoted by the same reference numerals, and redundant description is omitted. FIG. 6 is a diagram for describing vehicle control according to the second embodiment.

  In this embodiment, the difference from the first embodiment is that clutch release control is performed based on the amount of decrease in vehicle speed after the vehicle speed changes from acceleration to deceleration instead of the elapsed time from brake OFF to accelerator ON. It is a point to determine whether or not to shift to. Thus, the clutch release control can be performed only when the running tendency is clearly toward deceleration. While the fuel cut control is being executed and the engine 11 is being driven to rotate by the drive wheels 16, it is determined whether or not to shift to the clutch release control when the start of the acceleration operation by the driver is detected. The

  FIG. 6 is a time chart when the vehicle control of this embodiment is performed. FIG. 6 shows changes in (a) vehicle speed, (b) accelerator opening, and (c) clutch release command signal. The clutch release command signal is a command signal for causing the clutch hydraulic pressure control device 41 to release the clutch 40, and is output from the ECU 20 to the clutch hydraulic pressure control device 41.

  In this embodiment, the amount of decrease in vehicle speed from the vehicle speed (MAX vehicle speed) when the vehicle speed finally changes from acceleration to deceleration (hereinafter simply referred to as “vehicle speed decrease amount ΔV”) is the threshold value for the decrease amount. When the predetermined reduction amount is equal to or greater than ΔV1, clutch release control is executed in response to accelerator ON during fuel cut control. For example, at time t1 when the fuel cut control is executed and the engine 11 is rotationally driven by the drive wheels 16, the accelerator is turned off and the accelerator is turned on, and the vehicle speed reduction amount ΔV at this time is less than the reduction amount threshold value ΔV1. large. As a result, the clutch release command signal is turned ON, and clutch release control is executed. When the accelerator is turned off at time t2, the clutch release control ends. Similarly, the clutch release control is executed from time t3 to time t4. In other accelerators ON, since the vehicle speed decrease amount ΔV does not reach the decrease amount threshold value ΔV1 or the accelerator opening is large, the clutch release control is not executed. The MAX vehicle speed is reset every time the vehicle speed changes from deceleration to acceleration.

  In the vehicle control of the present embodiment, the ECU 20 releases the clutch without resuming the generation of power by the engine 11 only when the vehicle speed decrease amount ΔV is equal to or greater than the threshold value ΔV1 based on the decrease amount of the vehicle speed from the MAX vehicle speed. The control is executed to reduce the load of the engine 11 acting on the drive wheel 16. Clutch disengagement control is permitted only when the running tendency is clearly decelerating, and when acceleration / deceleration is frequently performed, firing is performed without performing clutch disengagement control in response to accelerator ON. Therefore, the driver's acceleration / deceleration operation status (intention) that appears in the transition of the vehicle speed up to that point is reflected in the judgment of whether to perform clutch release control, thereby improving drivability while improving fuel efficiency. Can be planned.

(Modification of the above embodiments)
A modification of each of the above embodiments will be described. The vehicle control system may reduce the engine brake by cylinder deactivation control instead of the clutch release control of each of the above embodiments. For example, by stopping at least some of the plurality of cylinders of the engine 11, the engine brake can be reduced as compared with the case where none of the cylinders are stopped. When the cylinder is deactivated, the opening and closing of at least one of the intake valve and the exhaust valve may be stopped. Whether or not to shift to the cylinder deactivation control mode can be determined in the same manner as whether or not the clutch release control in each of the above embodiments is executed. Further, the clutch release control and the cylinder deactivation control may be selectively executed. For example, based on the magnitude of deceleration when executed, when the accelerator opening is large, it is possible to perform control for decreasing the deceleration.

  As described above, the vehicle control system according to the present invention is useful for vehicle control when the start of acceleration operation is detected, and is particularly suitable for improving fuel consumption.

1 Vehicle 11 Engine 13 Automatic Transmission 16 Drive Wheel 20 ECU
21 accelerator position sensor 29 vehicle speed sensor 32 brake operation amount sensor 33 clutch input shaft rotational speed sensor 34 clutch output shaft rotational speed sensor 40 clutch 41 clutch hydraulic pressure control device α first predetermined value β second predetermined value T0 predetermined time

Claims (6)

Load changing means capable of changing the magnitude of the load by the power source acting on the drive wheel when the power source of the vehicle is rotated by the drive wheel of the vehicle;
A control device for controlling the load changing means,
The control device is capable of executing power source stop control for stopping generation of power by the power source when the vehicle is running,
The control device detects the end of the braking operation by the driver while the power source stop control is executed and the power source is rotationally driven by the driving wheel, and after the end of the braking operation is detected. When the start of the acceleration operation by the driver is detected, if the elapsed time from the end of the braking operation to the start of the acceleration operation is equal to or longer than a predetermined time, the generation of power by the power source is suppressed. The vehicle control system, wherein the load is reduced by the load changing means without being restarted. The end of the braking operation is detected based on the operation amount of the driver with respect to the operation member of the vehicle,
The predetermined time changes according to a change speed of the operation amount when the driver changes the operation amount of the operation member to an operation amount corresponding to the end of the braking operation, and the predetermined time when the change speed is large. The vehicle control system according to claim 1, wherein the vehicle control system is longer than the predetermined time when the change speed is small. The load changing means changes the degree of power transmission between the power source and the drive wheel,
The vehicle control system according to claim 1, wherein the control device reduces the magnitude of the load by reducing the degree of transmission of the power by the load changing unit. The load changing means is capable of switching between a state in which the power is transmitted and a state in which the power is not transmitted in a power transmission path between the power source and the driving wheel,
4. The vehicle control according to claim 1, wherein the control device reduces the magnitude of the load by switching to a state in which the power transmission is not performed in the transmission path by the load changing unit. 5. system. The end of the braking operation is detected based on the operation amount of the driver with respect to the operation member of the vehicle,
The control device, when the change amount of the operation amount when the driver changes the operation amount of the operation member to the operation amount corresponding to the end of the braking operation is equal to or higher than a predetermined speed, The vehicle control system according to claim 4, wherein the state in which the power is transmitted in the transmission path is maintained even if the elapsed time is equal to or longer than the predetermined time. Load changing means capable of changing the magnitude of the load by the power source acting on the drive wheel when the power source of the vehicle is rotated by the drive wheel of the vehicle;
A control device for controlling the load changing means,
The control device is capable of executing power source stop control for stopping generation of power by the power source when the vehicle is running,
The control device finally executes the control of the vehicle when the start of the acceleration operation by the driver is detected while the power source stop control is executed and the power source is rotationally driven by the drive wheels. When the vehicle speed has decreased from the vehicle speed when the vehicle speed is changed from the acceleration to the deceleration by a predetermined reduction amount or more, the load changing unit does not restart the generation of power by the power source. The vehicle control system characterized by reducing the magnitude of the load.

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