Vehicle control device, vehicle control method, and program

Abstract

[Problem] To alleviate a feeling of incongruity for a driver by suppressing a delay in the startup of an engine in relation to an accelerator operation while traveling. [Solution] This vehicle control device is used in a vehicle which travels by a driving force being transmitted from an engine to a driving wheel via a clutch. The control device is provided with a controller which performs: engine stopping control to stop a supply of fuel to the engine and release the clutch, to achieve a driving force interrupted state, if a state arises in which an accelerator operation is not being performed during travel; first control to perform engine startup and impart a torque transmission capacity to the clutch if, when in the driving force interrupted state, an accelerator operation is performed while the engine has a rotational speed higher than a first rotational speed; and second control to startup the engine after the engine has stopped, and impart a torque transmission capacity to the clutch after the engine has started up, if an accelerator operation is performed when the engine has a rotational speed at most equal to the first rotational speed while in the driving force interrupted state.

Description

[Technical Field]

[0001] The present invention relates to vehicle control and programming. [Background technology]

[0002] Patent Document 1 discloses a technology that provides an electric oil pump in addition to a mechanical oil pump, and supplies lubricating oil to the gears with the electric oil pump when performing N coasting. In N coasting, the clutch is disengaged during coasting, and the vehicle is driven with a lower engine speed than when the clutch is engaged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-213557 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle that runs by transmitting driving force from the engine to the drive wheels via a clutch, the driver may request acceleration by operating the accelerator while the clutch is in a state where driving force is cut off and fuel supply to the engine is stopped. However, in this case, depending on the method of starting the engine and supplying hydraulic pressure to the clutch, it may not be possible to start the engine quickly, resulting in a delayed start of the engine and slower acceleration of the vehicle, which may cause the driver to feel uncomfortable.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to suppress a delay in starting the engine in response to accelerator operation while driving, thereby reducing the sense of discomfort felt by the driver. [Means for solving the problem]

[0006] A vehicle control device according to one aspect of the present invention is used in a vehicle that runs by transmitting driving force from an engine to drive wheels via a clutch. When an accelerator pedal is not operated while the vehicle is running, the control device stops the fuel supply to the engine and releases the clutch to cut off the driving force, and in the cut-off state, the engine By restarting the fuel supply to the engine, the rotation of the engine can be shifted to autonomous rotation, and reverse rotation of the engine cannot occur. The controller is configured to start the engine and provide the clutch with torque transmission capacity when the accelerator is operated when the engine has a rotational speed higher than a first rotational speed, and to start the engine after the engine has stopped rotating and provide the clutch with torque transmission capacity after the engine has started when the accelerator is operated when the engine has a rotational speed lower than the first rotational speed in the driving force disconnected state.

[0007] According to yet another aspect of the present invention, there is provided a vehicle control method and program corresponding to the vehicle control device described above. [Effects of the Invention]

[0008] According to these aspects, when the accelerator pedal is operated after the engine rotation speed has dropped, the clutch does not have any torque transmission capacity until the engine starts, so the engine, which is about to stop rotating, is prevented from being dragged by the clutch and rotating. As a result, the engine rotation can be quickly stopped and then started. Therefore, the delay in engine start in response to accelerator pedal operation while driving is suppressed, and the driver's discomfort can be alleviated. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a vehicle according to this embodiment. [Figure 2] FIG. 2 is a flowchart showing an example of control in this embodiment. [Figure 3] FIG. 3 is a diagram illustrating the stopping and starting of the engine ENG. [Figure 4]FIG. 4 is a diagram showing a first example of a timing chart in this embodiment. [Figure 5] FIG. 5 is a diagram showing a second example of a timing chart in this embodiment. [Figure 6] FIG. 6 is a diagram showing a third example of a timing chart in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] FIG. 1 is a schematic diagram of a vehicle according to this embodiment. The vehicle has an engine ENG, a motor generator MG, a transmission TM, and drive wheels DW. The engine ENG constitutes the drive source of the vehicle. In the vehicle, engine torque Te of the engine ENG is transmitted to the drive wheels DW via the transmission TM. In other words, the transmission TM is provided in a power transmission path connecting the engine ENG and the drive wheels DW. A motor belt BLT_MG is provided on the engine ENG. The motor belt BLT_MG connects the engine ENG to an air conditioner compressor COMP and a motor generator MG, and mediates the transmission of power between them. Therefore, part of the engine torque Te can also be transmitted to the compressor COMP and the motor generator MG via the motor belt BLT_MG.

[0012] The motor generator MG is connected to the engine ENG via a motor belt BLT_MG in the power transmission path. The motor generator MG is electrically connected to the battery BATT via an inverter INV. The motor generator MG functions as an electric motor that receives power supply from the battery BATT to rotate and as a generator that rotates with an external force to generate electricity. In this embodiment, the motor generator MG is used as a generator, but is also configured as a belt start generator that drives the engine ENG via the motor belt BLT_MG when starting the engine ENG. This makes it possible to reduce the size of the motor generator MG to a size appropriate for starting the engine ENG, from the perspective of the power to be secured. Including the case where it is configured in this way, the motor generator MG can also provide motor assist by being used to drive the drive wheels DW together with the engine ENG.

[0013] The transmission TM includes a torque converter TC, a forward / reverse switching mechanism SWM, and a variator VA. The torque converter TC transmits power via a fluid. The torque converter TC enhances power transmission efficiency by engaging a lock-up clutch LU.

[0014] The forward / reverse switching mechanism SWM is provided in a power transmission path connecting the engine ENG and the variator VA. The forward / reverse switching mechanism SWM switches the rotation direction of the input rotation to switch between forward and reverse travel of the vehicle. The forward / reverse switching mechanism SWM includes a forward clutch FWD / C that is engaged when the forward range is selected, and a reverse brake REV / B that is engaged when the reverse range is selected. When the forward clutch FWD / C and the reverse brake REV / B are released, the transmission TM enters a neutral state, i.e., a state in which driving force is cut off. In this embodiment, the forward clutch FWD / C constitutes a clutch that transmits driving force from the engine ENG to the drive wheels DW. Such a clutch may be understood to be constituted by the forward clutch FWD / C and the reverse brake REV / B. The forward clutch FWD / C is a hydraulic clutch that is hydraulically operated.

[0015] The variator VA constitutes a belt continuously variable transmission mechanism having a primary pulley PRI, a secondary pulley SEC, and a belt BLT wound around the primary pulley PRI and the secondary pulley SEC. A primary pressure Ppri, which is the oil pressure of the primary pulley PRI, and a secondary pressure Psec, which is the oil pressure of the secondary pulley SEC, are supplied to the primary pulley PRI and the secondary pulley SEC, respectively, from a hydraulic control circuit 11, which will be described later.

[0016] The transmission TM further has a mechanical oil pump 21, an electric oil pump 22, and an electric motor 23. The mechanical oil pump 21 pumps oil to the hydraulic control circuit 11. The mechanical oil pump 21 is a mechanical oil pump driven by power from the engine ENG. The electric oil pump 22 pumps oil to the hydraulic control circuit 11 together with the mechanical oil pump 21, or independently. The electric oil pump 22 is provided auxiliary to the mechanical oil pump 21. The electric motor 23 drives the electric oil pump 22. The electric oil pump 22 may be understood to be configured with the electric motor 23.

[0017] The transmission TM further has a hydraulic control circuit 11 and a transmission controller 12. The hydraulic control circuit 11 is composed of a plurality of flow paths and a plurality of hydraulic control valves, and adjusts the pressure of oil supplied from a mechanical oil pump 21 and an electric oil pump 22 and supplies the oil to each part of the transmission TM. The transmission controller 12 is a controller for controlling the transmission TM, and is connected to an engine controller 13 for controlling the engine ENG so as to be able to communicate with each other. The engine controller 13 inputs to the transmission controller 12, for example, an output torque signal indicating the engine torque Te and a motor start initiation determination signal, which will be described later.

[0018] The transmission controller 12 and the engine controller 13 are each composed of one or more computers (microcomputers) equipped with a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and an input / output interface (I / O interface). Each of these controllers 12 and 13 is controlled by the CPU executing a program stored in the ROM or RAM. The program may be stored in a non-transitory storage medium such as a CD-ROM. The transmission controller 12, together with the engine controller 13, constitutes a controller 100 provided in a vehicle control device. The controller 100 may further include an integrated controller that performs integrated control of the transmission controller 12, engine controller 13, etc.

[0019] Signals from a sensor switch group 40 representing various sensor switches are input to the controller 100. The sensor switch group 40 includes, for example, a vehicle speed sensor that detects a vehicle speed VSP, an accelerator opening sensor that detects an accelerator opening APO, an engine rotation speed sensor that detects a rotation speed Ne of the engine ENG, and a brake sensor that detects brake fluid pressure.

[0020] The sensor / switch group 40 further includes, for example, a primary pressure sensor that detects the primary pressure Ppri, a secondary pressure sensor that detects the secondary pressure Psec, a primary rotational speed sensor that detects the rotational speed Npri that is the input rotational speed of the primary pulley PRI, a secondary rotational speed sensor that detects the rotational speed Nsec that is the output rotational speed of the secondary pulley SEC, a turbine rotational speed sensor that detects the rotational speed Ntb that is the output rotational speed of the torque converter TC, a position sensor that detects the operating position of the shift lever, and an oil temperature sensor that detects the oil temperature of the transmission TM. The rotational speed Npri is, for example, the rotational speed of the input shaft of the primary pulley PRI, the rotational speed Nsec is, for example, the rotational speed of the output shaft of the secondary pulley SEC, and the rotational speed Ntb is, for example, the rotational speed of the output shaft of the torque converter TC.

[0021] These signals are input to the transmission controller 12 directly or via the engine controller 13 or the like. The transmission controller 12 controls the transmission TM based on these signals. The transmission TM is controlled by controlling the hydraulic control circuit 11 and the electric oil pump 22 based on these signals. The hydraulic control circuit 11 performs hydraulic control of the lock-up clutch LU, forward clutch FWD / C, reverse brake REV / B, primary pulley PRI, secondary pulley SEC, etc. based on instructions from the transmission controller 12.

[0022] In a vehicle, the driver may operate the accelerator while the forward clutch FWD / C is in a state where driving force is cut off and the fuel supply to the engine ENG is in a state where it is stopped while the vehicle is traveling forward. However, in this case, depending on the method of starting the engine ENG and the method of supplying hydraulic pressure to the forward clutch FWD / C, it may not be possible to start the engine ENG quickly, resulting in a delay in starting the engine ENG and slowing down the acceleration of the vehicle, which may cause discomfort to the driver.

[0023] In view of these circumstances, in this embodiment, the controller 100 performs the control described below.

[0024] FIG. 2 is a flowchart showing an example of control performed by controller 100. First, steps S1 to S5 will be described. The processing of steps S1 to S5 constitutes a first control. The first control is a control that starts engine ENG and provides forward clutch FWD / C with a torque transmission capacity when the accelerator is operated while engine ENG has a rotation speed Ne higher than first rotation speed Ne1 in a driving force disconnection state due to sailing stop control. The processing of steps S1 to S3 and step S5 can be performed by transmission controller 12. The processing of step S4 can be performed by engine controller 13 for starting engine ENG and by transmission controller 12 for hydraulic pressure supply.

[0025] In step S1, it is determined whether or not the vehicle is in a sailing stop. When sailing stop control is executed, the vehicle enters a sailing stop state. In sailing stop control, when a sailing stop condition is met, fuel supply to the engine ENG is stopped and the forward clutch FWD / C is released to cut off driving force. The sailing stop conditions include the vehicle speed VSP being higher than a set vehicle speed VSP1, the accelerator pedal not being depressed (the accelerator not being operated), the brake pedal not being depressed (the brake not being operated), and the forward range being selected in the transmission TM. The sailing stop condition is met when all of the conditions included in the sailing stop condition are met. The set vehicle speed VSP1 can be set in advance to distinguish between low speed and medium to high speed.

[0026] The vehicle is considered to be in a sailing stop state while the sailing stop condition is satisfied. Therefore, in step S1, it is possible to determine whether or not the sailing stop condition is satisfied by determining whether or not the vehicle is in a sailing stop state. In addition to stopping the fuel supply, sailing stop control disengages the forward clutch FWD / C to cut off the driving force, thereby extending the coasting distance and improving fuel efficiency. Sailing stop control corresponds to engine stop control. If the determination in step S1 is negative, the process ends temporarily, and if the determination in step S1 is positive, the process proceeds to step S2.

[0027] In step S2, it is determined whether the accelerator is ON. If the driver is not depressing the accelerator pedal (if the accelerator pedal is not depressed), that is, if the accelerator is not being operated, it is determined that the accelerator is OFF, and the process is temporarily terminated. If the driver is depressing the accelerator pedal (if the accelerator pedal is depressed), that is, if the accelerator is being operated, it is determined that the accelerator is ON. In this case, the sailing stop condition is not established, so the engine ENG is started and hydraulic pressure is supplied to the forward clutch FWD / C, as will be explained below. If the determination in step S2 is positive, the process proceeds to step S3.

[0028] In step S3, it is determined whether the rotation speed Ntb is higher than the first rotation speed Ntb1. The determination in step S3 is made by the transmission controller 12, and at this stage, the engine ENG has not yet been started and hydraulic pressure has not yet been supplied to the forward clutch FWD / C. Therefore, at this stage, the rotation speed Ne decreases in the state where the driving force is cut off, and as a result, the rotation speed Ntb also decreases in accordance with the decrease in the rotation speed Ne. For this reason, in step S3, the determination is substantially made regarding the rotation speed Ne based on the rotation speed Ntb.

[0029] The first rotation speed Ntb1 is a judgment value for permitting the start of the rotating engine ENG, and when the rotation speed Ne is relatively high, the rotation of the engine ENG can be transitioned to autonomous rotation, for example, by fuel recovery, which will be described later, and thus the start of the engine ENG is permitted. The first rotation speed Ntb1 is further set as a judgment value for determining whether the rotation speed Ne is within a rotation speed region R in which reverse rotation of the engine ENG may occur. The rotation speed region R will be described later. Such first rotation speed Ntb1 corresponds to a first rotation speed Ne1, which is a similar judgment value for the rotation speed Ne, and is set in advance. When the rotation speed Ntb is higher than the first rotation speed Ntb1, the start of the rotating engine ENG is permitted, and the process proceeds to step S4.

[0030] In step S4, engine ENG is started by fuel recovery and hydraulic pressure is supplied to forward clutch FWD / C. Engine ENG is started as a restart to recover from a sailing stop state. Fuel recovery is the resumption of fuel supply to engine ENG, and engine ENG is started by transitioning to an autonomous rotation state due to fuel recovery. Hydraulic pressure can be supplied to forward clutch FWD / C by supplying oil from electric oil pump 22, which allows forward clutch FWD / C to have torque transmission capacity.

[0031] The hydraulic pressure supply in step S4 is performed in response to accelerator operation, regardless of whether the engine ENG has started or not. The hydraulic pressure supply in step S4 is performed before the engine ENG stops rotating. In step S4, the start of the engine ENG and the hydraulic pressure supply to the forward clutch FWD / C do not have to start at the same time. The start of the engine ENG by fuel recovery may be accompanied by driving force assistance from the motor generator MG.

[0032] In step S5, it is determined whether the rotation speed Ntb is higher than the first rotation speed Ntb1. In step S5, it is determined whether the engine ENG has started. The determination in step S5 can be made, for example, by determining whether the rotation speed Ntb has not fallen below the first rotation speed Ntb1 within a predetermined time period after the start of engine ENG starting by fuel recovery. If the engine ENG has started, there will be no particular decrease in the rotation speed Ntb. Therefore, in this case, a positive determination is made in step S5, and the processing is temporarily terminated.

[0033] The first control may be a control that is performed in the driving force cut-off state and the fuel supply to the engine ENG is stopped state regardless of whether or not the vehicle is in a sailing stop state. In other words, in the first control, the driving force cut-off state and the fuel supply stop state do not have to be achieved by the sailing stop control.

[0034] Next, the processing from step S7 to step S10 will be described. These processings are performed when a negative determination is made in step S3 after passing through step S1 and step S2. The processings from step S1 to step S3 and step S7 to step S10 constitute a second control. The second control is a control in which, if the accelerator is operated when the engine ENG has a rotation speed Ne equal to or less than the first rotation speed Ne1 in a driving force disconnection state due to sailing stop control, the engine ENG is started after the rotation of the engine ENG has stopped, and the forward clutch FWD / C is provided with a torque transmission capacity after the engine ENG has started. The processings of steps S7, S9, and S10 can be performed by the transmission controller 12, and the processing of step S8 can be performed by the transmission controller 12 and the engine controller 13.

[0035] If the determination in step S3 is negative, starting of the rotating engine ENG is not permitted, and the process proceeds to step S7. In step S7, it is determined whether the rotation of the engine ENG has stopped. If the determination in step S7 is positive, the process proceeds to step S8, where the engine ENG is started. The stop of the rotation of the engine ENG is determined based on a change in the rotation speed Ne, as will be explained next, and the engine ENG is started after the determined stop of the rotation of the engine ENG, i.e., after the rotation has stopped in a determined manner.

[0036] FIG. 3 is a diagram illustrating the stopping and starting of the engine ENG. The dashed line indicates the case where the engine ENG is started by fuel recovery. In this case, the engine ENG is started while the rotation speed Ne is higher than the first rotation speed Ne1 in response to accelerator operation, and the rotation speed Ne increases. As shown by the thin line in FIG. 3, the rotation speed Ne actually fluctuates up and down. Therefore, even after the rotation speed Ne reaches zero, it continues to fluctuate up and down and gradually decays and converges toward zero. In other words, the rotation of the engine ENG may not immediately stop after the rotation speed Ne reaches zero, but may fluctuate between forward and reverse rotation at a low rotation speed Ne. For this reason, the stopping of the engine ENG is determined based on such changes in the rotation speed Ne. In this example, the engine ENG stops as determined by the timing Tstop at which the rotation speed Ne converges to approximately zero.

[0037] In this way, the stop of rotation of the engine ENG does not have to be a state in which the rotation speed Ne has completely converged to zero and the rotation of the engine ENG has completely stopped. In other words, the stop of rotation of the engine ENG may be based on a change in the rotation speed Ne converging to zero, and may be a state in which the rotation speed Ne has converged to approximately zero after becoming zero or has converged to some extent toward zero.

[0038] The engine controller 13 determines whether the rotation of the engine ENG has stopped, and determines whether the rotation of the engine ENG has stopped based on the change in the rotation speed Ne converging to zero as described above. For example, this determination can be made by determining whether the rotation speed Ne has reached zero a predetermined number of times or more since the rotation speed Ne, which decreases in response to the stop of fuel supply, became zero. Alternatively, this determination can be made by determining whether a predetermined time has elapsed since the rotation speed Ne, which decreases in response to the stop of fuel supply, became zero.

[0039] When the rotation of the engine ENG has stopped as specified, a motor start-up determination signal, which is a signal indicating that the rotation of the engine ENG has stopped, is transmitted from the engine controller 13 to the transmission controller 12. Therefore, in step S7, it is determined whether the motor start-up determination signal is ON or not, thereby determining whether the rotation of the engine ENG has stopped.

[0040] While the rotational speed converges to zero, the engine ENG rotates in both forward and reverse directions, and the engine ENG rotating in the reverse direction acts as a large load on the engine ENG when it is started, which rotates in the forward direction. On the other hand, an engine rotational speed sensor may be used that does not distinguish between positive and negative values ​​and cannot distinguish between rotational directions.

[0041] For this reason, in this embodiment, the first rotation speed Ne1 is set to be higher than the rotation speed Ne that converges toward zero. In other words, even if a negative rotation speed Ne is set to be positive, the first rotation speed Ne1 is set so that the rotation speed Ne that converges toward zero only fluctuates within a range less than the first rotation speed Ne1. As a result, start-up by fuel recovery, which is permitted at rotation speeds Ne higher than the first rotation speed Ne1, is not permitted in the rotation speed region R that ranges from zero to the first rotation speed Ne1 and in which reverse rotation of the engine ENG may occur. This prevents the engine ENG from acting as a heavy load during start-up, even if the engine ENG is started by fuel recovery during reverse rotation. As a result, it is possible to prevent the engine ENG from failing to start due to fuel recovery.

[0042] Even when the engine ENG is rotating in reverse, it is possible to start the engine ENG while the motor generator MG is providing driving force assistance. However, in this case, a large load is placed on the motor belt BLT_MG. For this reason, in this embodiment, the engine ENG is started after the rotation of the engine ENG has stopped. This prevents the engine ENG from being started while it is rotating in reverse, thereby reducing the load on the motor belt BLT_MG when the motor generator MG is used for starting the engine ENG. Furthermore, since hydraulic pressure is not yet supplied to the forward clutch FWD / C at this time, the engine ENG is prevented from being dragged by the forward clutch FWD / C and rotating. Therefore, the rotation speed Ne tends to converge quickly toward zero, which causes the engine ENG to stop rotating quickly, making it possible to start the engine ENG quickly.

[0043] Returning to FIG. 2, in step S8, the engine ENG is started by the motor generator MG. The start of the engine ENG in this case is also performed as a restart for returning from a sailing stop state. In step S8, the engine ENG is started by using the driving force of the motor generator MG to crank the engine ENG. Therefore, when the start of the engine ENG is initiated in step S8, the transmission controller 12 drives the motor generator MG to perform cranking, while the engine controller 13 performs fuel injection and ignition of the engine ENG.

[0044] In step S9, it is determined whether the rotation speed Ntb is higher than a second rotation speed Ntb2. The second rotation speed Ntb2 is a rotation speed Ntb higher than the first rotation speed Ntb1 and is set in advance as a determination value for supplying hydraulic pressure to the forward clutch FWD / CL. The second rotation speed Ntb2 is set higher than the first rotation speed Ntb1 by providing hysteresis to the first rotation speed Ntb1. The second rotation speed Ntb2 indicates a second rotation speed Ne2, which is a similar determination value for the rotation speed Ne. If the determination in step S9 is negative, the process returns to step S9, and the same process is repeated. If the determination in step S9 is positive, it is also determined that the start of the engine ENG has been completed. In this case, the process proceeds to step S10.

[0045] In step S10, hydraulic pressure is supplied to the forward clutch FWD / C, thereby allowing the forward clutch FWD / C to have a torque transmission capacity. In step S10, after the engine ENG has stopped rotating as determined in step S7, the engine ENG has begun to start in step S8, and then a positive determination is made in step S9, so that the forward clutch FWD / C has a torque transmission capacity after the engine ENG has started. Therefore, when the engine ENG is fluctuating in rotation at a low rotation speed Ne, the forward clutch FWD / C does not have a torque transmission capacity.

[0046] This prevents the engine ENG from rotating due to being dragged by the forward clutch FWD / C, as described above. As a result, the engine ENG can be started quickly, which reduces the delay in starting the engine ENG in response to accelerator operation and reduces the sense of discomfort felt by the driver. In addition, because the engine ENG is started after the engine ENG has stopped rotating, starting the engine ENG while it is rotating in reverse is also avoided. As a result, this also contributes to reducing the load on the motor belt BLT_MG. The process ends temporarily after step S10.

[0047] Even when starting the engine ENG by fuel recovery is attempted, there are cases where the engine ENG cannot be started. In this case, a negative determination is made in step S5 and the process proceeds to step S6. In step S6, the hydraulic pressure supply to the forward clutch FWD / C is stopped. This prevents the forward clutch FWD / C from having a torque transmission capacity even when the engine ENG cannot be started by fuel recovery and the engine ENG is fluctuating in rotation at a low rotation speed Ne. This makes it possible to quickly stop the rotation of the engine ENG and then start it. For this reason, in this case, the process proceeds to step S7 following step S6, and the same process as when a negative determination is made in step S3 is performed. The process of step S6 can be performed by the transmission controller 12.

[0048] The second control may be performed in the same manner as the first control, regardless of whether the driving force is cut off and the fuel supply is stopped, or not, regardless of whether the sailing stop is in progress.

[0049] FIG. 4 shows a first example of a timing chart corresponding to the flowchart shown in FIG. 3. Before timing T1, the engine is in a sailing stop state, and the engine speed Ntb gradually decreases with the accelerator pedal OFF (not being operated). At timing T1, the accelerator is operated and the accelerator pedal is ON. As a result, the sailing stop condition is no longer met. At timing T1, the engine speed Ntb is below the first engine speed Ntb1 and is not stopped. Therefore, in this example, hydraulic pressure is supplied to the forward clutch FWD / C after the engine ENG has stopped rotating.

[0050] At time T2, the rotation speed Ntb, which had been decreasing, becomes constant. However, as mentioned above, the rotation speed Ne may actually be fluctuating up and down, and the engine ENG may not have stopped rotating at time T2. The engine ENG stops rotating at time T3, the motor start start determination is turned ON, and the engine ENG is started. As a result, the rotation speed Ntb begins to increase from time T3.

[0051] As described above, the motor start start determination signal is transmitted from the engine controller 13 to the transmission controller 12 and is turned ON when the rotation of the engine ENG stops. Therefore, when the motor start start determination signal is turned ON, the rotation speed Ne has converged to approximately zero. Therefore, when the engine ENG is started at timing T3, the engine ENG is prevented from acting as a large load, thereby protecting the belt BLT.

[0052] The rotational speed Ntb becomes higher than the second rotational speed Ntb2 at timing T4. As a result, the command pressure for forward clutch FWD / C is made higher than the command pressure for release of forward clutch FWD / C, thereby supplying hydraulic pressure to forward clutch FWD / C. The command pressure is set to a pre-charge pressure at timing T4 that fills forward clutch FWD / C with oil prior to engagement, to a stroke pressure at timing T5 that eliminates any backlash in the piston of forward clutch FWD / C, and to a full engagement pressure at timing T6 that fully engages forward clutch FWD / C. The torque transmission capacity of forward clutch FWD / C is generated between timing T5 and timing T6, when the command pressure is set to the stroke pressure.

[0053] Before timing T3, hydraulic pressure has not yet been supplied to the forward clutch FWD / C. Therefore, between timing T2 and timing T3, dragging of the forward clutch FWD / C prevents the engine ENG from rotating, and the rotation speed Ne quickly converges to zero. As a result, the engine ENG quickly stops rotating at timing T3, allowing the engine ENG to start up quickly.

[0054] FIG. 5 is a diagram showing a second example of a timing chart corresponding to the flowchart shown in FIG. 3. At timing T11, as in the first example, the sailing stop condition is not satisfied due to the accelerator pedal being ON. At timing T11, the rotation speed Ntb is higher than the first rotation speed Ntb1. Therefore, in this example, when the accelerator pedal is depressed, the engine ENG is started by fuel recovery and hydraulic pressure is supplied to the forward clutch FWD / C. In other words, in terms of timing, the engine ENG is started by fuel recovery and hydraulic pressure is supplied to the forward clutch FWD / C immediately after the accelerator pedal is depressed.

[0055] Hydraulic pressure can be supplied to the forward clutch FWD / C when the rotational speed Ntb is higher than the second rotational speed Ntb2. In this example, the rotational speed Ntb is higher than the second rotational speed Ntb2 at timing T11. Therefore, hydraulic pressure supply to the forward clutch FWD / C begins at timing T11, and the command pressure is set to the pre-charge pressure at timing T11, the stroke pressure at timing T12, and the full engagement pressure at timing T13. As a result, the forward clutch FWD / C has a torque transmission capacity between timing T12 and timing T13. In addition, the engine ENG is started by fuel recovery immediately after timing T11, which is before timing T12, thereby increasing the rotational speed Ntb. In this example, the rotational speed Ntb is higher than the first rotational speed Ntb1 at timing T11, so starting the engine ENG by fuel recovery allows the engine ENG to start quickly.

[0056] FIG. 6 is a diagram showing a third example of a timing chart corresponding to the flowchart shown in FIG. 3. At timing T21, as in the first and second examples, the sailing stop condition is not satisfied due to the accelerator pedal being ON. At timing T21, the rotation speed Ntb is higher than the first rotation speed Ntb1. Therefore, in this example, when the accelerator pedal is depressed, the engine ENG is started by fuel recovery and hydraulic pressure is supplied to the forward clutch FWD / C, and hydraulic pressure is supplied to the forward clutch FWD / C immediately after the accelerator pedal is depressed at timing T21.

[0057] On the other hand, in this example, even though an attempt is made to start the engine ENG by fuel recovery immediately after the accelerator pedal is depressed at time T21, the engine ENG does not start (the rotation speed does not increase). As a result, the rotation speed Ntb continues to decrease and becomes equal to or less than the first rotation speed Ntb1 at time T22. For this reason, immediately after time T22, the command pressure is set to the release command pressure, which stops the hydraulic pressure supply to the forward clutch FWD / C. The decreasing rotation speed Ntb becomes constant at time T23, and from time T23 onwards, the engine ENG begins to rotate at a low rotation speed Ne.

[0058] However, at this time, the hydraulic pressure supply to the forward clutch FWD / C has already been stopped, so the forward clutch FWD / C does not have any torque transmission capacity. This prevents the engine ENG from rotating due to dragging of the forward clutch FWD / C, and the engine ENG quickly stops rotating at timing T24. As a result, the motor start-up commencement determination signal turns ON, and the engine ENG starts, increasing the rotation speed Ntb. At timing T25, the rotation speed Ntb becomes higher than the second rotation speed Ntb2, and the hydraulic pressure supply to the forward clutch FWD / C is resumed. The command pressure is set to the pre-charge pressure at timing T25, the stroke pressure at timing T26, and the fully engaged pressure at timing T27, and the forward clutch FWD / C assumes a torque transmission capacity between timing T26 and timing T27.

[0059] 4 to 6, the engine ENG and forward clutch FWD / C only need to be in a fuel supply stop state and a driving force disconnection state, and are not limited to cases where the fuel supply stop state and the driving force disconnection state are caused by sailing stop control. Even in this case, by similarly starting the engine ENG and supplying hydraulic pressure to the forward clutch FWD / C, it is possible to suppress a delay in starting the engine ENG and protect the belt BLT.

[0060] Next, the main effects of this embodiment will be described.

[0061] (1) A vehicle control device according to this embodiment is used in a vehicle that travels by transmitting driving force from an engine ENG to drive wheels DW via a forward clutch FWD / C. This vehicle control device includes a controller 100 that, when the accelerator pedal is released while the vehicle is traveling, stops the supply of fuel to the engine ENG and releases the forward clutch FWD / C to establish a driving force disconnection state. When the accelerator pedal is turned on in this driving force disconnection state when the rotation speed Ntb is higher than a first rotation speed Ntb1 (i.e., when the engine ENG has a rotation speed Ne higher than the first rotation speed Ne1), starts the engine ENG and provides the forward clutch FWD / C with a torque transmission capacity. When the accelerator pedal is turned on in this driving force disconnection state when the rotation speed Ntb is equal to or lower than the first rotation speed Ntb1 (i.e., when the engine ENG has a rotation speed Ne equal to or lower than the first rotation speed Ne1), starts the engine ENG after rotation of the engine ENG has stopped, and provides the forward clutch FWD / C with a torque transmission capacity after the engine ENG has started.

[0062] With this configuration, when the accelerator pedal is turned on after the rotation speed Ne has dropped, the forward clutch FWD / C does not have any torque transmission capacity until the engine ENG starts. This prevents the engine ENG, which is about to stop rotating, from being dragged by the forward clutch FWD / C and rotating. As a result, the engine ENG can be started after quickly stopping its rotation. This reduces delays in starting the engine ENG in response to accelerator pedal operation while driving, reducing discomfort felt by the driver. Furthermore, because the forward clutch FWD / CL has a torque transmission capacity only after the engine ENG has stopped rotating, it is possible to avoid starting the engine ENG while it is rotating in reverse. This also prevents the engine ENG from acting as a heavy load when starting.

[0063] (2) The vehicle has a motor generator MG connected to the engine ENG via a motor belt BLT_MG. The engine ENG is started by the motor generator MG. In this case, by preventing the engine ENG from being started while it is rotating in reverse, even if the rotation direction of the engine ENG cannot be determined, the load on the motor belt BLT_MG that is involved when the engine ENG is started using the motor generator MG can be reduced. As a result, this is significant in that it can reduce further strength requirements for the motor belt BLT_MG and improve the durability of the motor belt BLT_MG.

[0064] (3) The forward clutch FWD / C is a hydraulic clutch. The controller 100 supplies hydraulic pressure to the forward clutch FWD / C, thereby providing the forward clutch FWD / C with torque transmission capacity. When the accelerator pedal is released while driving, the controller 100 stops the fuel supply to the engine ENG and releases the forward clutch FWD / C to cut off the driving force. In this driving force cut-off state, when the rotation speed Ntb is higher than the first rotation speed Ntb1, the accelerator pedal is turned on to start the engine ENG and supply hydraulic pressure to the forward clutch FWD / C. If the rotation speed Ntb becomes equal to or lower than the first rotation speed Ntb1 after the start of hydraulic pressure supply to the forward clutch FWD / C, the controller 100 stops the hydraulic pressure supply to the forward clutch FWD / C.

[0065] With this configuration, even if the engine ENG experiences rotational fluctuations at a low rotational speed Ne after the first control is executed, the forward clutch FWD / C does not need to have a torque transmission capacity. Therefore, in such a case, the engine ENG can be prevented from rotating due to drag of the forward clutch FWD / C, and the engine ENG can be quickly stopped.

[0066] (4) After stopping the supply of hydraulic pressure to the forward clutch FWD / C, the controller 100 starts the engine ENG after the rotation of the engine ENG has stopped, and when the rotation speed Ntb becomes higher than a second rotation speed Ntb2 that is higher than the first rotation speed Ntb1 (i.e., when the rotation speed Ne of the engine ENG becomes higher than a second rotation speed Ne2 that is higher than the first rotation speed Ne1), the controller 100 resumes the supply of hydraulic pressure to the forward clutch FWD / C.

[0067] With this configuration, when the engine ENG starts to fluctuate at a low rotation speed Ne after the first control is executed, the engine ENG can be started quickly by appropriately starting the engine ENG and supplying hydraulic pressure to the forward clutch FWD / C.

[0068] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0069] In the embodiment of the present invention, the sailing stop control has been described as engine stop control, but it is not limited to the sailing stop control and can also be applied to, for example, coast stop control. The coast stop control is executed when a coast stop condition is met. The coast stop condition is defined as a condition in which the vehicle speed VSP is low (less than a preset vehicle speed), the accelerator pedal is not depressed, the brake pedal is depressed, and the forward range is selected in the transmission TM. The preset vehicle speed is, for example, the vehicle speed VSP at which the lockup clutch LU is released. [Explanation of symbols]

[0070] 12: Transmission controller 13: Engine controller 100: Controller (computer) BLT_MG: Motor belt (belt) CL: Clutch DW: Drive wheel ENG: Engine FWD / C: Forward clutch (clutch) MG: Motor generator (motor)

Claims

1. A control device for a vehicle that travels by transmitting driving force from an engine to drive wheels via a clutch, When the accelerator pedal is not operated during driving, the fuel supply to the engine is stopped and the clutch is released to cut off the driving force, When an accelerator operation is performed while the engine is in the driving force cut-off state and the engine has a rotation speed that is higher than a first rotation speed at which the rotation of the engine can be transitioned to autonomous rotation by resuming fuel supply to the engine and reverse rotation of the engine cannot occur, the engine is started and a torque transmission capacity is provided to the clutch, a controller that, when an accelerator operation is performed while the engine has a rotation speed equal to or less than the first rotation speed in the driving force disconnected state, starts the engine after the engine stops rotating, and provides the clutch with a torque transmission capacity after the engine has started; Vehicle control device.

2. The vehicle control device according to claim 1, the vehicle has a motor connected to the engine via a belt; The engine is started by the motor. Vehicle control device.

3. The vehicle control device according to claim 1 or 2, the clutch is a hydraulic clutch, The controller supplies hydraulic pressure to the clutch to provide the clutch with a torque transmission capacity, When an accelerator pedal operation is not performed during driving, the controller stops the fuel supply to the engine and releases the clutch to bring the driving force into a disconnected state, When an accelerator operation is performed while the engine has a rotation speed higher than a first rotation speed in the driving force disconnected state, the engine is started and hydraulic pressure is supplied to the clutch, and when the rotation speed of the engine becomes equal to or lower than the first rotation speed after the hydraulic pressure supply to the clutch has started, the hydraulic pressure supply to the clutch is stopped. Vehicle control device.

4. The vehicle control device according to claim 3, the controller starts the engine after the rotation of the engine has stopped after stopping the supply of hydraulic pressure to the clutch, and resumes the supply of hydraulic pressure to the clutch when the rotation speed of the engine becomes higher than the first rotation speed and higher than a second rotation speed that is set with hysteresis relative to the first rotation speed. Vehicle control device.

5. A control method for a vehicle that travels by transmitting driving force from an engine to drive wheels via a clutch, comprising: When the accelerator pedal is not operated during driving, the fuel supply to the engine is stopped and the clutch is released to cut off the driving force; When an accelerator operation is performed while the engine is in the driving force cut-off state, the engine rotation can be shifted to autonomous rotation by restarting fuel supply to the engine and the engine has a rotation speed higher than a first rotation speed at which reverse rotation of the engine cannot occur, and the engine is started and the clutch is provided with a torque transmission capacity; When an accelerator operation is performed while the engine has a rotation speed equal to or less than the first rotation speed in the driving force disconnected state, the engine is started after the engine stops rotating, and the clutch is provided with a torque transmission capacity after the engine has started. A vehicle control method including:

6. A computer-executable program for a vehicle that runs by transmitting driving force from an engine to drive wheels via a clutch, When the accelerator pedal is not operated during driving, the fuel supply to the engine is stopped and the clutch is released to cut off the driving force, When an accelerator operation is performed while the engine is in the driving force cut-off state and the engine has a rotation speed that is higher than a first rotation speed at which the rotation of the engine can be transitioned to autonomous rotation by resuming fuel supply to the engine and reverse rotation of the engine cannot occur, the engine is started and a torque transmission capacity is provided to the clutch, When an accelerator operation is performed while the engine is rotating at a speed equal to or lower than the first rotation speed in the driving force disconnected state, the computer executes a procedure of starting the engine after the engine stops rotating, and providing the clutch with a torque transmission capacity after the engine has started. program.

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