JP2015124831A - Vehicle control device, and vehicle control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device for suppressing the occurrence of a pull shock at a re-acceleration time after a coast stop control.SOLUTION: In the case where an engine 1 is automatically stopped during the running so that it is predicted at a subsequent re-startup time that the revolving speed on the side of the engine 1 is lower than the revolving speed on the side of drive wheels 7, an engine rotation speed rise control to make the engine rotation speed higher than the maximum of the engine rotation speed by the engine complete combustion is executed before the friction fastening element starts the coupling.

Description

  The present invention relates to a vehicle control device and a vehicle control method.

  In order to improve fuel efficiency, it is known to perform coast stop control that automatically stops the engine while the vehicle is running. During coast stop control, as the engine stops, the mechanical oil pump that is driven by the rotation of the engine is also stopped, and hydraulic pressure cannot be supplied from the mechanical oil pump. For example, a belt type continuously variable transmission is installed. In vehicles, there is a risk of belt slippage. On the other hand, it is possible to provide an electric oil pump and supply hydraulic pressure using the electric oil pump while the engine is stopped. However, providing the electric oil pump increases the cost, and an electric oil pump is provided. Space is required.

  Patent Document 1 discloses a control device that suppresses belt slippage without using an electric oil pump during coast stop control.

JP 2012-241746 A

  When the electric oil pump is not provided, the frictional engagement element is released during the coast stop control because the hydraulic pressure for maintaining the engagement of the frictional engagement element such as the clutch cannot be supplied. When the coast stop control is completed and the engine is restarted, hydraulic pressure is supplied from the mechanical oil pump, and the frictional engagement element is fastened.

  During coast stop control, for example, when there is a driver's acceleration request such as when an accelerator pedal is depressed, coast stop control is terminated before the vehicle stops. During coast stop control, the rotational speed of the friction engagement element on the engine side (hereinafter referred to as the input side rotational speed) is affected by the engine rotational speed, and the input side rotational speed rapidly decreases when the engine stops. On the other hand, the rotational speed of the frictional engagement element on the drive wheel side (hereinafter referred to as the output-side rotational speed) is affected by the vehicle speed and decreases more slowly than the input-side rotational speed. If the coast stop control is finished before the vehicle stops, the vehicle speed at that time is low, and the input side rotational speed after engine restart is higher than the output side rotational speed, the output is The side rotation speed increases and the vehicle accelerates. On the other hand, when the coast stop control is finished, the vehicle speed at that time is high, and the input side rotational speed after engine restart is lower than the output side rotational speed, when the friction engagement element is engaged, the output side rotational speed is Even if the driver temporarily decreases and the driver intends to accelerate, the vehicle temporarily decelerates, and a shock due to deceleration (hereinafter referred to as pulling shock) may occur, which may cause the driver to feel uncomfortable. is there.

  In order to improve fuel efficiency, coast stop control is executed even in a high vehicle speed region, and coast stop control may be terminated in a state where the vehicle speed is high and the output side rotational speed is high. Further, the input side rotational speed when the engine is restarted is determined depending on the engine rotational speed at the time of the complete explosion of the engine, and does not become higher than a certain rotational speed. Therefore, when the coast stop control is terminated in the high vehicle speed region, the engine is restarted, and the friction engagement element is engaged, the input side rotational speed after the engine restart is lower than the output side rotational speed. It may occur and give the driver a feeling of strangeness.

  In addition, the gear ratio of the transmission is set to the coast stop in order to generate the driving force according to the driver's acceleration request when restarting the engine, such as when the accelerator pedal is depressed after the coast stop control is finished. In some cases, the speed ratio is set to the Low side when the control is executed. In such a case, the output side rotational speed is further increased, a pulling shock is likely to occur, and the driver is likely to feel uncomfortable.

  The present invention was invented to solve such a problem, and at the time of starting the engine after the coast stop control is finished, the vehicle is prevented from decelerating and the occurrence of a pulling shock is suppressed. The purpose is to suppress the sense of incongruity given to people.

  A vehicle control device according to an aspect of the present invention is a vehicle control device that controls a vehicle in which a frictional engagement element is provided between an engine and a drive wheel, and that automatically stops or restarts the engine while the vehicle is running. At the time of restart, it is predicted whether the rotation speed of the friction engagement element on the engine side when the engine rotation speed is at the maximum value due to the complete explosion of the engine is lower than the rotation speed of the friction engagement element on the drive wheel side. And an engine rotation speed increase control for making the engine rotation speed higher than the maximum engine rotation speed due to the complete explosion of the engine when the engine rotation speed is predicted to be lower than the drive wheel rotation speed. And an engine speed control means for executing before the engagement of the frictional engagement element.

  A vehicle control method according to another aspect of the present invention is a vehicle control method for controlling a vehicle in which a frictional engagement element is provided between an engine and a drive wheel, and automatically stops or restarts the engine while the vehicle is running. When the engine speed is maximum due to the complete explosion of the engine, it is predicted at the time of restart whether the rotation speed of the friction engagement element on the engine side is lower than the rotation speed of the friction engagement element on the drive wheel side. When the engine speed is predicted to be lower than the speed of the drive wheel, the friction engagement element engages the engine speed increase control to increase the engine speed higher than the maximum engine speed by the complete engine explosion. Run before starting.

  According to these aspects, after the engine is automatically stopped during traveling, when the engine is restarted, the rotational speed of the friction engagement element on the engine side is increased by making the engine rotational speed higher than the maximum value of the engine rotational speed due to the complete explosion of the engine. Can be high. As a result, when the frictional engagement element is fastened, the difference between the rotational speed of the frictional engagement element on the engine side and the rotational speed of the frictional engagement element on the drive wheel side is reduced, or the rotation of the frictional engagement element on the engine side is reduced. By making the speed higher than the rotational speed of the frictional engagement element on the drive wheel side and fastening the frictional engagement element, the vehicle is prevented from decelerating, the occurrence of pulling shocks is suppressed, and the uncomfortable feeling given to the driver is suppressed. can do.

It is a schematic block diagram which shows the vehicle of this embodiment. It is a schematic block diagram of an engine. It is a schematic block diagram of a controller. It is a flowchart explaining the engine restart control of 1st Embodiment. It is a map which shows the relationship between a target engine speed and a basic engine speed. It is a time chart when not using the engine restart control of this embodiment. It is a time chart at the time of using the engine restart control of this embodiment. It is a flowchart explaining the engine restart control of 2nd Embodiment. It is a time chart which shows the change of the air quantity of an intake passage at the time of engine restart, and engine speed. It is a map which shows the relationship between the air quantity upstream of an intake valve, an engine speed, and ignition timing.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the “transmission ratio” of a transmission mechanism is a value obtained by dividing the input rotational speed of the transmission mechanism by the output rotational speed of the transmission mechanism.

  FIG. 1 is a schematic configuration diagram showing a vehicle according to the present embodiment. The vehicle includes a gasoline engine (hereinafter referred to as an engine) 1 as a driving source, and the output rotation of the engine 1 is a torque converter 2 with a lock-up clutch, a first gear train 3, a transmission 4, a second gear train 5, It is transmitted to the drive wheel 7 via the differential device 6.

  The engine 1 will be described with reference to FIG.

  Air that is controlled by the throttle valve 51 provided in the intake passage 50 and the auxiliary air valve 53 provided in the auxiliary air passage 52 that bypasses the throttle valve 51 is drawn into the engine 1 through the intake valve 54. Further, fuel is injected by the injector 55 based on the amount of air taken in, and an air-fuel mixture is formed in the combustion chamber 56 of the engine 1. By igniting the air-fuel mixture with the spark plug 57, the air-fuel mixture burns. The exhaust after combustion is discharged to the exhaust passage 59 via the exhaust valve 58.

  The transmission 4 is provided with a mechanical oil pump 10 m that receives rotation of the engine 1 and is driven by using a part of the power of the engine 1. Further, the transmission 4 is provided with a hydraulic control circuit 11 that regulates the hydraulic pressure (hereinafter referred to as “line pressure PL”) from the mechanical oil pump 10 m and supplies the hydraulic pressure to each part of the transmission 4.

  The transmission 4 includes a belt-type continuously variable transmission mechanism (hereinafter referred to as “variator 20”) and an auxiliary transmission mechanism 30.

  The variator 20 includes a primary pulley 21, a secondary pulley 22, and a V belt 23 that is wound around the pulleys 21 and 22. Each of the pulleys 21 and 22 includes a fixed conical plate, a movable conical plate that is arranged with a sheave surface facing the fixed conical plate, and forms a V-groove between the fixed conical plate, and the movable conical plate. The hydraulic cylinders 23a and 23b are provided on the back surface of the movable cylinder to displace the movable conical plate in the axial direction. When the hydraulic pressure supplied to the hydraulic cylinders 23a and 23b is adjusted, the width of the V groove changes, the contact radius between the V belt 23 and each pulley 21 and 22 changes, and the transmission ratio of the variator 20 changes steplessly. .

  The subtransmission mechanism 30 is a transmission mechanism having two forward speeds and one reverse speed. The sub-transmission mechanism 30 is connected to a Ravigneaux type planetary gear mechanism 31 in which two planetary gear carriers are connected, and a plurality of friction elements connected to a plurality of rotating elements constituting the Ravigneaux type planetary gear mechanism 31 to change their linkage state. Fastening elements (Low brake 32, High clutch 33, Rev brake 34) are provided. When the hydraulic pressure supplied to each of the frictional engagement elements 32 to 34 is adjusted and the engagement / release state of each of the frictional engagement elements 32 to 34 is changed, the gear position of the auxiliary transmission mechanism 30 is changed. Specifically, the first speed is achieved when the Low brake 32 is engaged and the High clutch 33 and Rev brake 34 are released, the High clutch 33 is engaged, and the Low brake 32 and Rev brake 34 are released. The second gear is achieved. Further, the reverse gear is achieved when the Rev brake 34 is engaged and the Low brake 32 and the High clutch 33 are disengaged.

  The controller 12 is a controller that controls the engine 1 and the transmission 4 in an integrated manner. As shown in FIG. 3, the CPU 12, a storage device 122 including a RAM / ROM, an input interface 123, an output interface 124, The bus 125 interconnects these components.

  The input interface 123 includes an output signal of an accelerator opening sensor 41 that detects an accelerator opening APO that is an operation amount of an accelerator pedal, an output signal of a rotation speed sensor 42 that detects an input rotation speed Npri of the transmission 4, and a vehicle speed VSP. The output signal of the vehicle speed sensor 43 for detecting the pressure, the output signal of the line pressure sensor 44 for detecting the line pressure PL, the output signal of the brake fluid pressure sensor 46 for detecting the brake fluid pressure, the output signal of the air flow meter 47, etc. .

  The storage device 122 stores a control program for the engine 1, a shift control program for the transmission 4, and various map tables used in these programs. The CPU 121 reads and executes a program stored in the storage device 122, performs various arithmetic processes on various signals input via the input interface 123, and performs fuel injection amount signal, ignition timing signal, throttle opening. A drive signal for the degree signal and the shift control signal is generated, and the generated signal is output to the engine 1 and the hydraulic control circuit 11 via the output interface 124. Various values used in the arithmetic processing by the CPU 121 and the arithmetic results are appropriately stored in the storage device 122.

  The hydraulic control circuit 11 includes a plurality of flow paths and a plurality of hydraulic control valves. The hydraulic control circuit 11 controls a plurality of hydraulic control valves on the basis of the shift control signal from the controller 12 to switch the hydraulic pressure supply path and adjusts the required hydraulic pressure from the line pressure PL generated by the mechanical oil pump 10m. This is supplied to each part of the transmission 4. Thereby, the gear ratio of the transmission 4 (the gear ratio of the variator 20 and the gear position of the auxiliary transmission mechanism 30) is changed.

  In the present embodiment, in order to improve the fuel consumption of the engine 1, coast stop control is performed in which the engine 1 is automatically stopped while the vehicle is traveling. The coast stop control is executed, for example, when the following conditions (a) to (d) are satisfied, and is terminated when any of the following conditions (a) to (d) is not satisfied.

(A): Vehicle is running (VSP ≠ 0)
(B): The vehicle speed VSP is equal to or lower than a predetermined vehicle speed VSP1 (VSP ≦ VSP1).
(C): The foot is released from the accelerator pedal (accelerator opening APO = 0)
(D): The brake pedal is depressed (the brake fluid pressure is a predetermined value or more)

  When the coast stop control is executed, the engine 1 is stopped, so the mechanical oil pump 10m is also stopped, and the line pressure PL generated in the mechanical oil pump 10m is eliminated, so that the hydraulic pressure supplied to the frictional engagement elements 32 to 34 is eliminated. Decreases and the frictional engagement elements 32-34 are released. Therefore, when the coast stop control is finished and the engine 1 is restarted, the hydraulic pressure generated by the mechanical oil pump 10m by the restart of the engine 1 is supplied to any of the frictional engagement elements 32 to 34 that are fastened during traveling. Then, any one of the frictional engagement elements 32 to 34 is fastened. In the following, the frictional engagement elements 32 to 34 that are engaged during traveling will be described simply as the frictional engagement elements 32 to 34.

  When the coast stop control is finished and the engine 1 is restarted, the driver intends to accelerate the vehicle, but the input side rotational speed Ni that is the rotational speed on the engine 1 side after the engine restart is When the output side rotational speed No, which is the rotational speed on the drive wheel 7 side, is lower, the output side rotational speed No is temporarily reduced by fastening the frictional engagement elements 32 to 34. That is, although the driver intends to accelerate, the vehicle decelerates, a pulling shock occurs, and the driver feels uncomfortable.

  When the vehicle speed VSP when restarting the engine 1 is low, the output side rotational speed No is also low. When the coast stop control is terminated and the frictional engagement elements 32 to 34 are engaged, the input side rotation after the engine restarts. The speed Ni is higher than the output side rotational speed No, and no pulling shock occurs. In such a case, in order to prevent the engine 1 from blowing up, the frictional engagement elements 32 to 34 may be fastened immediately after the coast stop control is finished.

  In order to improve the fuel consumption of the engine 1, the predetermined vehicle speed VSP1 is set high, and the vehicle speed VSP when the engine 1 is restarted after finishing the coast stop control may be high. In such a case, the input side rotational speed Ni after restarting the engine may be lower than the output side rotational speed No. When the frictional engagement elements 32 to 34 are engaged, a pulling shock is generated.

  Therefore, in this embodiment, engine restart control is executed so as to suppress the occurrence of pulling shock when coast stop control is terminated. The engine restart control will be described with reference to the flowchart of FIG. Here, it is assumed that any of the conditions (a) to (d) described above is not satisfied, the coast stop control is terminated, and the engine 1 is restarted.

  In step S100, the controller 12 ends the coast stop control and restarts the engine 1.

  In step S101, the controller 12 detects the vehicle speed VSP when the engine 1 is restarted based on the output signal of the vehicle speed sensor 43.

  In step S102, the controller 12 calculates the target engine speed Neo based on the gear ratio of the variator 20, the gear position of the subtransmission mechanism 30, and the vehicle speed VSP. The target engine speed Neo is determined based on the current state of the transmission 4 (the gear ratio of the variator 20 and the speed of the auxiliary transmission mechanism 30) and the vehicle speed VSP. It is the engine speed which becomes equal. That is, the engine speed is such that no pulling shock occurs when the frictional engagement elements 32 to 34 are engaged. The engine rotation speed at which the input side rotation speed Ni is equal to the output side rotation speed No is calculated as the target engine rotation speed Neo. The target engine rotation speed Neo is such that the input side rotation speed Ni is equal to or higher than the output side rotation speed No. Any engine speed may be used.

  In step S103, the controller 12 compares the target engine rotational speed Neo with the basic engine rotational speed Neb, so that the input rotational speed Ni is lower than the output rotational speed No when the frictional engagement elements 32-34 are engaged. Predict whether or not a pulling shock will occur. The basic engine speed Neb is the maximum value of the engine speed when the engine 1 is started and the engine 1 is blown up by the complete explosion without performing engine speed increase control which will be described later. The basic engine speed Neb is preset and stored. If the target engine rotational speed Neo is equal to or lower than the basic engine rotational speed Neb, the current process is terminated. If the target engine rotational speed Neo is higher than the basic engine rotational speed Neb, the process proceeds to step S104.

  The relationship between the target engine speed Neo and the basic engine speed Neb will be described using the map of FIG. Here, it is assumed that the gear ratio of the variator 20 is the lowest. In this case, the target engine rotation speed Neo is determined by the vehicle speed VSP and the gear position of the auxiliary transmission mechanism 30, and is higher when the low brake 32 is engaged than when the high clutch 34 is engaged. In addition, the target engine speed Neo increases as the vehicle speed VSP increases. For example, when the friction engagement elements 32 to 34 to be engaged are the low brake 32 and the vehicle speed VSP is “V1”, the target engine speed Neo is “N1”, which is lower than the basic engine speed Neb. In this state, even if the engine rotational speed increase control is not performed, the input side rotational speed Ni is higher than the output side rotational speed No. Therefore, even if the Low brake 32 is engaged, no pulling shock is generated. Therefore, in this case, the current process is terminated. On the other hand, when the vehicle speed VSP is “V2”, the target engine speed Neo is “N2”, which is higher than the basic engine speed Neb. In this state, when the low brake 32 is engaged without performing the engine speed increase control, the input side rotational speed Ni becomes lower than the output side rotational speed No, and a pulling shock is generated. Therefore, in such a case, the process proceeds to step S104.

  In step S104, the controller 12 outputs the input side rotational speed Ni and the output when the input side rotational speed Ni after engine restart is predicted to be lower than the output side rotational speed No when the frictional engagement elements 32 to 34 are engaged. The engine rotational speed increase control is executed so that the rotational speed difference from the side rotational speed No becomes small. Specifically, the controller 12 advances the ignition timing so that the engine rotational speed Ne becomes the target engine rotational speed Neo, and makes the input side rotational speed Ni equal to the output side rotational speed No.

  When the engine 1 is not stopped, the intake valve 54 is opened and air is sucked into the engine 1 so that the intake passage 50 has a negative pressure. However, when the engine 1 is stopped by performing coast stop control. Since the throttle valve 51 is fully closed and air flows to the upstream side of the intake valve 54 via the auxiliary air passage 52, the intake passage 50 becomes atmospheric pressure (negative pressure = 0). This is the same as the state in which the throttle valve 51 is fully opened. When the engine 1 is started from such a state, the fuel corresponding to the amount of intake air is injected by the injector 55, so that the engine 1 is blown up. . In order to suppress this, normally, the ignition timing by the spark plug 57 is retarded to suppress blowing up.

  In the present embodiment, by increasing the ignition timing, the engine rotational speed Ne is increased, the input-side rotational speed Ni is increased, and the input-side rotational speed Ni is made equal to the output-side rotational speed No.

  In step S105, the controller 12 determines the input side rotational speed Ni and the output based on the output signal of the rotational speed sensor 42, the output signal of the vehicle speed sensor 43, the speed ratio of the variator 20, and the gear position of the subtransmission mechanism 30. The side rotation speed No is calculated.

  In step S106, the controller 12 determines whether or not the input side rotational speed Ni is equal to or higher than the output side rotational speed No. The process proceeds to step S107 when the input side rotational speed Ni becomes equal to or higher than the output side rotational speed No. When the input side rotational speed Ni is lower than the output side rotational speed No, the process returns to step S105.

  In step S107, the controller 12 starts the engagement of the friction engagement elements 32-34. In the present embodiment, the engine speed increase control is executed before the engagement of the frictional engagement elements 32 to 34 is started.

  In step S <b> 108, the controller 12 determines whether or not the engagement of the frictional engagement elements 32 to 34 has been completed. For example, the controller 12 calculates the input-side rotational speed Ni and the output-side rotational speed No in the same manner as in step S105. If the input-side rotational speed Ni and the output-side rotational speed No are equal, the friction engagement elements 32 to 34 are calculated. It is determined that the engagement of the friction engagement elements 32 to 34 has been completed when a predetermined time has elapsed since the start of engagement or when the line pressure PL becomes higher than the predetermined pressure based on the output signal of the line pressure sensor 44. The predetermined pressure is preset and stored for a predetermined time. Until the engagement of the frictional engagement elements 32 to 34 is completed, the controller 12 repeatedly performs this determination. When the engagement of the frictional engagement elements 32 to 34 is completed, the process proceeds to step S109.

  In step S109, the controller 12 ends the engine speed increase control.

  Next, engine restart control will be described with reference to the time charts of FIGS. FIG. 6 is a time chart when the engine restart control of the present embodiment is not used, and FIG. 7 is a time chart when the engine restart control of the present embodiment is used.

  First, a case where this embodiment is not used will be described.

  When coast stop control is started at time t0, the engine 1 is stopped. As a result, the engine rotational speed Ne decreases, and the input side rotational speed Ni also decreases. Note that the vehicle is running, the brake pedal is not depressed, and the amount of decrease in the output side rotational speed No is small.

  At time t1, the coast stop control is terminated and the engine 1 is restarted. The vehicle speed VSP at time t1 is the vehicle speed when the engine 1 is restarted. Thereby, the engine rotational speed Ne increases and the input side rotational speed Ni also increases. However, since the vehicle speed VSP is high, the output side rotational speed No is high, and the input side rotational speed Ni is lower than the output side rotational speed No.

  At time t2, the engagement of the frictional engagement elements 32-34 is started. Since the input side rotational speed Ni is lower than the output side rotational speed No, when the frictional engagement elements 32 to 34 are fastened, the output side rotational speed No is lowered and a pulling shock is generated.

  Next, a case where this embodiment is used will be described.

  Up to time t1, it is the same as the case where this embodiment is not used.

  At time t1, the coast stop control is terminated and the engine 1 is restarted. In the present embodiment, since the engine rotational speed increase control is performed, the engine rotational speed Ne becomes higher and the input-side rotational speed Ni also becomes higher than when the present embodiment is not used.

  When the input side rotational speed Ni becomes equal to the output side rotational speed No at time t2, the engagement of the frictional engagement elements 32 to 34 is started. Since the input side rotational speed Ni is equal to the output side rotational speed No, pulling shock does not occur even when the frictional engagement elements 32 to 34 are fastened.

  The effect of 1st Embodiment of this invention is demonstrated.

  When the coast stop control is terminated and the engine 1 is restarted, the input side rotational speed Ni can be increased by making the engine rotational speed VSP higher than the maximum value of the engine rotational speed due to the complete explosion of the engine. As a result, when the friction engagement elements 32 to 34 are engaged, the engine rotation speed increase control for making the input side rotation speed Ni equal to or higher than the output side rotation speed No is executed before the friction engagement elements 32 to 34 start engagement. . Thereby, after the coast stop control is completed, when the engine 1 is restarted and the frictional engagement elements 32 to 34 are engaged, it is possible to suppress the occurrence of a pulling shock (effect corresponding to claim 1).

  The target engine speed Neo is increased as the vehicle speed VSP increases. When the vehicle speed VSP is high, the output side rotational speed No is also high. Therefore, in such a case, it is possible to suppress the occurrence of a pulling shock by increasing the target engine rotational speed Neo and increasing the input-side rotational speed Ni (effect corresponding to claim 3). .

  The target engine speed Neo when the low brake 32 is engaged is set higher than the target engine speed Neo when the high clutch 33 is engaged. When the shift stage of the subtransmission mechanism 30 is the Low brake 32, the output side rotational speed Ne becomes high. Therefore, in such a case, it is possible to suppress the occurrence of a pulling shock by increasing the target engine rotation speed Neo and increasing the input-side rotation speed Ni (effect corresponding to claim 4). .

  When the frictional engagement elements 32 to 34 are fastened, if the input side rotational speed Ni is fastened in a state higher than the output side rotational speed No, a feeling of extrusion and a fastening shock corresponding to the differential rotation are generated. In order to reduce the push-out feeling and the fastening shock, the friction fastening elements 32 to 34 must be fastened slowly, and the time required for fastening becomes long. Further, if the target engine speed Neo is increased in order to shorten the time required for engagement, an engagement shock is generated. In this embodiment, in the engine speed increase control, the target engine speed Neo is set so that the input side speed Ni and the output side speed No are equal, thereby suppressing the push-out feeling and the occurrence of the fastening shock. However, the frictional engagement elements 32 to 34 can be quickly engaged (effect corresponding to claim 5).

  If the engine rotational speed increase control is executed after completion of the engagement of the frictional engagement elements 32 to 34, the fuel consumption of the engine 1 may be deteriorated. In this embodiment, when the engagement of the frictional engagement elements 32-34 is completed, the engine This can be prevented by terminating the rotation speed increase control. Further, if the engine rotation speed increase control that suppresses the feeling of pushing out and the engagement shock is continued after the completion of the engagement of the friction engagement element, the drive force control intended by the driver is not transferred. For example, it is impossible to generate the driving force intended by the driver by performing fuel injection according to the accelerator opening. In this embodiment, it is possible to quickly shift to the driving force control intended by the driver by minimizing the execution time of the engine speed increase control (effect corresponding to claim 7).

  A second embodiment of the present invention will be described.

  The second embodiment is different in engine restart control. The engine restart control of the second embodiment will be described with reference to the flowchart of FIG.

  The control from step S200 to step S207 is the same as the control from step S100 to step S107 of the first embodiment.

  In step S <b> 208, the controller 12 calculates the air amount Qa upstream of the intake valve 54 based on the signal from the air flow meter 47. The air amount Qa upstream of the intake valve 54 is the amount of air between the throttle valve 51 and the intake valve 54. When the engine 1 is restarted after the coast stop control is completed, the air quantity Qa upstream of the intake valve 54 is reduced as shown in FIG. As a result, the negative pressure in the intake passage 50 increases. FIG. 9 is a time chart showing changes in the air amount Qa of the intake passage 50 and the engine rotational speed Ne when the engine is restarted. Note that when coast stop control is started, the engine 1 is stopped and air is no longer drawn into the engine 1, so the air amount Qa increases.

  In step S209, the controller 12 calculates a predetermined amount Qb based on the target engine speed Neo. The predetermined amount Qb is a lower limit air amount upstream of the intake valve 54 that can achieve the target engine speed Neo without opening the throttle valve 51. The predetermined amount Qb will be described with reference to FIG. FIG. 10 is a map showing the relationship among the air amount Qa upstream of the intake valve 54, the engine rotational speed Ne, and the ignition timing. The engine rotation speed Ne increases as the negative pressure decreases and the air amount Qa upstream of the intake valve 54 increases (close to atmospheric pressure), and increases as the ignition timing becomes earlier. The ignition timing is set to a limit ignition timing in consideration of knocking and the like. When a certain target engine speed Neo is determined, a predetermined amount Qb that is an air amount upstream of the intake valve 54 that can achieve the target engine speed Neo with respect to the limit ignition timing is determined. That is, if the air amount Qa upstream of the intake valve 54 is smaller than the predetermined amount Qb, the engine speed Ne cannot be made equal to or higher than the target engine speed Neo even if the ignition timing is advanced to the limit ignition timing. Therefore, the controller 12 calculates a predetermined amount Qb that can make the engine rotational speed Ne equal to or higher than the target engine rotational speed Neo based on the target engine rotational speed Neo.

  In step S210, the controller 12 determines whether or not the air amount Qa upstream of the intake valve 54 has become equal to or less than a predetermined amount Qb. The process proceeds to step S211 when the air amount Qa upstream of the intake valve 54 becomes equal to or less than the predetermined amount Qb.

  In step S211, the controller 12 ends the engine speed increase control.

  The effect of 2nd Embodiment of this invention is demonstrated.

  When the air amount Qa upstream of the intake valve 54 reaches the predetermined amount Qb, the engine speed increase control is terminated. That is, the engine speed increase control is performed only in a region where the engine speed Ne can be increased only by advancing the ignition timing without increasing the fuel injection amount injected from the injector 55. Thereby, it is possible to increase the engine rotational speed Ne, increase the input-side rotational speed Ni, and suppress the occurrence of the pulling shock while suppressing the deterioration of the fuel consumption of the engine 1 (effect corresponding to claim 8).

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  The engine restart control described above may be applied to a stepped transmission, a transmission composed of only a variator, or the like. Further, the engine restart control described above may be applied to the hybrid vehicle.

  In this embodiment, it is limited to the coast stop control in which the engine 1 is automatically stopped during traveling. However, in the idle stop control in which the engine 1 is automatically stopped during the stop, the vehicle speed VSP is zero, and the engine This is because pulling shock does not occur during restart.

  In step S103 (step S203), the target engine rotational speed Neo and the basic engine rotational speed Neb are compared, but the controller 12 compares the vehicle speed VSP with the second predetermined vehicle speed (predetermined vehicle speed) VSP2 to determine the vehicle speed. When the VSP is higher than the second predetermined vehicle speed VSP2, it may be determined that a pulling shock occurs. The second predetermined vehicle speed VSP2 is a vehicle speed lower than the first predetermined vehicle speed VSP1, and is set in advance as a value that does not cause a pulling shock when the friction engagement elements 32 to 34 are engaged. For example, when the gear ratio of the variator 20 is the lowest and the frictional engagement elements 32 to 34 to be engaged are the low brakes 32, the vehicle speed is such that no pulling shock is generated. A pulling shock can be predicted even with such a simple configuration (effect corresponding to claim 2). Further, the input side rotational speed Ni and the output side rotational speed No are calculated based on the basic engine rotational speed Neb, the vehicle speed VSP, and the gear position of the auxiliary transmission mechanism 30, and the input side rotational speed Ni and the output side rotational speed No are calculated. May be compared. This also makes it possible to predict the occurrence of a pulling shock.

  When an electronically controlled throttle valve is used as the throttle valve 51, the engine rotational speed Ne may be increased by increasing the opening of the throttle valve 51 in the engine rotational speed increase control. Further, the engine rotation speed increase control can be applied to a vehicle equipped with a diesel engine. In this case, the engine rotation speed can be increased by increasing the fuel injection amount. Further, in the engine speed increase control, when the engine speed Ne cannot be increased to the target engine speed Neo only by making the ignition timing earlier, the opening degree of the throttle valve 51 may be increased. Thereby, the engine rotational speed Ne can be increased, the input side rotational speed Ni can be increased, and the occurrence of a pulling shock can be suppressed. In the case of a hybrid vehicle including a motor on the output shaft of the engine 1, the engine rotational speed Ne may be increased by driving the motor.

  When calculating the target engine speed Neo, the target engine speed Neo may be calculated according to the engagement state of the lockup clutch of the torque converter 2. When the torque converter 2 is in the converter state, there is a rotational speed difference between the input and output shafts of the torque converter 2. Therefore, in consideration of this rotational speed difference, in the converter state, in the lockup state The target engine speed Neo is made higher than that. Thereby, regardless of the state of the lock-up clutch of the torque converter 2, it is possible to suppress the occurrence of a pulling shock (effect corresponding to claim 6). In addition, the target engine speed Neo may be increased in consideration of component variations and the like. That is, in the engine rotational speed increase control, the engine rotational speed Ne may be increased so that the input-side rotational speed Ni is higher than the output-side rotational speed No. When the target engine rotational speed Neo is increased and the input-side rotational speed Ni is higher than the output-side rotational speed No, the time during which the frictional engagement elements 32 to 34 can be engaged without generating a pulling shock becomes longer, and frictional engagement is performed. Fastening of the elements 32 to 34 is facilitated.

  In the above embodiment, in step S101 (step S201), the vehicle speed VSP when the coast stop control is finished is detected as the vehicle speed VSP when the engine 1 is restarted. However, the vehicle speed VSP is preset after the coast stop control is finished. The vehicle speed VSP within the predetermined time may be detected as the vehicle speed VSP when the engine 1 is restarted.

  In the above embodiment, in the engine rotational speed increase control, the input side rotational speed Ni is set to be equal to or higher than the output side rotational speed No. However, it is sufficient if the difference between the input side rotational speed Ni and the output side rotational speed No can be reduced. By doing so, the pulling shock can be reduced and the uncomfortable feeling given to the driver can be reduced.

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 7 Drive wheel 4 Transmission 12 Controller (Engine control means, prediction means, engine rotation speed control means)
20 Variator 30 Sub-transmission mechanism 51 Throttle valve 54 Intake valve

Claims (9)

A vehicle control device for controlling a vehicle provided with a frictional engagement element between an engine and a drive wheel,
Engine control means for automatically stopping or restarting the engine during vehicle travel;
Whether the rotational speed of the frictional engagement element on the engine side is lower than the rotational speed of the frictional engagement element on the drive wheel side when the engine rotational speed is at the maximum value due to the complete explosion is determined during the restart. Prediction means to predict;
Increasing the engine rotation speed when the engine rotation speed is predicted to be lower than the rotation speed on the drive wheel side, causing the engine rotation speed to be higher than the maximum engine rotation speed due to the complete explosion of the engine An engine rotation speed control means for executing control before the friction engagement element starts to be engaged. The vehicle control device according to claim 1,
The prediction means predicts that the rotational speed on the engine side is lower than the rotational speed on the drive wheel side when the vehicle speed at the time of restart is equal to or higher than a predetermined vehicle speed. . The vehicle control device according to claim 1 or 2,
The vehicle engine control apparatus, wherein the engine rotation speed control means increases the engine rotation speed as the vehicle speed at the time of restart is higher. The vehicle control device according to any one of claims 1 to 3,
The engine control apparatus according to claim 1, wherein the engine rotation speed control means increases the engine rotation speed as the transmission gear ratio is lower. The vehicle control device according to any one of claims 1 to 4,
The vehicle control apparatus according to claim 1, wherein the engine rotation speed control means increases the engine rotation speed so that the rotation speed on the engine side and the rotation speed on the drive wheel side are equal. The vehicle control device according to any one of claims 1 to 5,
The vehicle includes a torque converter between the engine and the frictional engagement element,
When the torque converter is in a converter state when executing the engine speed increase control, the engine rotation speed control means indicates the engine rotation speed, and the engine in the case where the torque converter is in a lock-up state. A vehicle control device characterized by being higher than the rotational speed. The vehicle control device according to any one of claims 1 to 6,
The engine control apparatus according to claim 1, wherein the engine rotation speed control means ends the engine rotation speed increase control when the engagement of the frictional engagement element is completed. The vehicle control device according to any one of claims 1 to 7,
The vehicle control apparatus according to claim 1, wherein the engine rotation speed control means ends the engine rotation speed increase control when an air amount between the throttle valve and the intake valve becomes a predetermined amount or less. A vehicle control method for controlling a vehicle provided with a frictional engagement element between an engine and a drive wheel,
Automatically stop or restart the engine while the vehicle is running,
Whether the rotational speed of the frictional engagement element on the engine side is lower than the rotational speed of the frictional engagement element on the drive wheel side when the engine rotational speed is at the maximum value due to the complete explosion is determined during the restart. Predict,
Increasing the engine rotation speed when the engine rotation speed is predicted to be lower than the rotation speed on the drive wheel side, causing the engine rotation speed to be higher than the maximum engine rotation speed due to the complete explosion of the engine A vehicle control method, wherein the control is executed before the frictional engagement element starts to be engaged.

Images