JP7448430B2 - Coasting control device - Google Patents

Description

The present invention relates to a coasting control device, and particularly to a coasting control device applied to a vehicle equipped with a continuously variable transmission.

In recent years, continuously variable transmissions (CVT), such as chain and belt types, have been widely put into practical use as automatic transmissions for vehicles, as they can change the gear ratio steplessly, eliminate shift shock, and improve fuel efficiency. ing. Continuously variable transmissions such as chain-type transmissions consist of a primary pulley (drive pulley) installed on the input shaft, a secondary pulley (driven pulley) installed on the output shaft, and a power transmission element such as a chain that spans these pulleys. The gear ratio is changed steplessly by changing the groove width of each pulley and changing the winding diameter of the power transmission element.

On the other hand, in order to further improve fuel efficiency, when the accelerator pedal is released while the vehicle is coasting (coasting/sailing), the driving power source (e.g. engine) is stopped and the driving power source is stopped. Coasting control (coasting control/sailing control) has been proposed in which the drive power source is separated from the drive system by releasing a clutch provided between the drive wheel and the drive wheel, and the vehicle travels using inertia force (for example, coasting control/sailing control). (See Patent Document 1).

Here, in the vehicle control device disclosed in Patent Document 1, in a vehicle employing a continuously variable transmission, a forward/reverse switching mechanism is configured to switch between forward and reverse rotation of the drive wheels (forward and reverse movement of the vehicle). By releasing the forward clutch/reverse brake, power transmission between the driving power source (engine) and the driving wheels is cut off, and the vehicle coasts.

Japanese Patent Application Publication No. 2014-46713

By the way, an attempt is made to apply the above-mentioned coasting control (coasting function) to a vehicle in which a clutch (a forward/reverse switching mechanism with a forward clutch/reverse brake) is provided on the downstream side (driving wheel side) of a continuously variable transmission. In this case, in order to reduce friction and improve fuel efficiency, stop the engine and release the clutch (forward clutch) while coasting to reduce friction and improve fuel efficiency. No driving force is input to the variator, and the number of revolutions per unit time (hereinafter referred to as the number of revolutions) of the continuously variable transmission (variator) decreases. That is, the speed difference (rotational speed difference) between the rotational speed of the continuously variable transmission and the vehicle speed (wheel speed) increases.

Therefore, if you subsequently try to return to normal driving from coasting, it is necessary to re-engage the forward clutch, but the speed difference between the rotational speed of the continuously variable transmission (variator) and the vehicle speed (wheel speed) Since the difference in rotational speed is large, there is a risk of shock or sudden deceleration occurring when the forward clutch is re-engaged.

The present invention has been made to solve the above problems, and includes a coasting control device that releases a clutch interposed between a continuously variable transmission and a driving wheel during coasting. It is an object of the present invention to provide a coasting control device that can reduce shocks caused by re-fastening a clutch when returning to normal running.

A coasting control device according to the present invention is provided between a continuously variable transmission that converts and outputs the driving force of an engine and drive wheels of a vehicle, and is configured to transmit driving force from the continuously variable transmission to the drive wheels of the vehicle. A clutch that intermittents power, a detection means that detects the rotation speed of the continuously variable transmission, and coasting control that stops the engine and releases the clutch when predetermined coasting control conditions are satisfied. coasting control means, the coasting control means gradually engaging the clutch when the number of revolutions of the continuously variable transmission becomes less than a first predetermined number of revolutions while executing the coasting control. Then, when the number of rotations of the continuously variable transmission becomes equal to or higher than a second predetermined number of rotations higher than the first predetermined number of rotations, the clutch is released.

According to the coasting control device according to the present invention, coasting control is executed in which the engine is stopped and the clutch is released when a predetermined coasting control condition is satisfied. If the number of revolutions of the continuously variable transmission becomes less than the first predetermined number of revolutions while coasting control is being executed, the clutch is gradually engaged, and then the number of revolutions of the continuously variable transmission becomes the first number of revolutions. When the rotational speed reaches a second predetermined rotational speed that is higher than the first predetermined rotational speed, the clutch is released. Therefore, during coasting, control is performed so that the rotation speed of the continuously variable transmission does not drop too much, that is, so that the difference between the rotation speed of the continuously variable transmission and the vehicle speed (rotation speed equivalent to the vehicle speed) does not increase too much. be able to. As a result, it is possible to reduce shocks caused by re-engagement of the clutch when returning from coasting to normal running.

In the coasting control device according to the present invention, it is preferable that the second predetermined rotation speed is set higher than the first predetermined rotation speed by a predetermined value or more.

In this way, the rotation speed of the continuously variable transmission can be maintained between the first predetermined rotation speed and the second predetermined rotation speed. Further, by providing hysteresis between the second predetermined rotation speed and the first predetermined rotation speed, it is possible to prevent frequent engagement and disconnection of the clutch.

In the coasting control device according to the present invention, it is preferable that the first predetermined rotation speed and the second predetermined rotation speed are set to increase as the vehicle speed increases.

In this way, it is possible to appropriately control the difference between each of the first predetermined rotation speed and the second predetermined rotation speed and the vehicle speed (revolution speed equivalent to the vehicle speed), thereby reducing shocks, etc. when the clutch is re-engaged. It becomes possible to reduce the amount accurately.

In the coasting control device according to the present invention, it is preferable that the first predetermined rotation speed and the second predetermined rotation speed are corrected according to the gear ratio and/or oil temperature of the continuously variable transmission. .

In this way, it becomes possible to more appropriately reduce shocks and the like when the clutch is re-engaged, taking into consideration the gear ratio and/or oil temperature of the continuously variable transmission.

In the coasting control device according to the present invention, it is preferable that the clutch is a forward clutch that constitutes a forward/reverse switching mechanism that switches between normal rotation and reverse rotation of the driving wheels.

In this case, a forward clutch constituting a forward/reverse switching mechanism can be used (also used) as the clutch.

The coasting control device according to the present invention further includes a second clutch that is interposed between the engine and the continuously variable transmission to connect and disconnect the driving force transmitted from the engine to the continuously variable transmission, and the coasting control device Preferably, the means release the second clutch when a predetermined coast control condition is satisfied.

In this way, when the clutch is engaged and the continuously variable transmission is rotated from the drive wheel side, it is possible to prevent the engine from rotating along with it (reduce friction).

According to the present invention, in a coasting control device that releases a clutch interposed between a continuously variable transmission and a driving wheel during coasting, the clutch can be re-engaged when returning from coasting to normal running. It becomes possible to reduce the resulting shock and the like.

FIG. 1 is a block diagram showing the configuration of a coasting control device according to an embodiment. It is a flow chart which shows the processing procedure of coasting control by a coasting running control device concerning an embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in the figures, the same reference numerals are used for the same or corresponding parts. Further, in each figure, the same elements are given the same reference numerals and redundant explanations will be omitted.

First, the configuration of a coasting control device 1 according to an embodiment will be described using FIG. 1. FIG. 1 is a block diagram showing the configuration of a coasting control device 1. As shown in FIG.

The engine 10 may be of any type, but is, for example, a horizontally opposed, direct injection, four-cylinder gasoline engine. In the engine 10, air taken in from an air cleaner (not shown) is throttled by an electronically controlled throttle valve (hereinafter simply referred to as "throttle valve") 13 provided in the intake pipe, passes through the intake manifold, and enters the engine 10. It is inhaled into each cylinder formed. Here, the amount of air taken in from the air cleaner is detected by an air flow meter 61. Further, the throttle valve 13 is provided with a throttle opening sensor 14 that detects the opening of the throttle valve 13. Each cylinder is equipped with an injector that injects fuel. Further, each cylinder is equipped with an ignition plug that ignites the air-fuel mixture and a coil with a built-in igniter that applies a high voltage to the ignition plug. In each cylinder of the engine 10, a mixture of intake air and fuel injected by an injector is ignited by a spark plug and combusted. The exhaust gases after combustion are discharged through the exhaust pipe.

In addition to the air flow meter 61 and the throttle opening sensor 14 described above, a cam angle sensor is attached near the camshaft of the engine 10 for determining the cylinders of the engine 10. Further, a crank angle sensor is attached near the crankshaft of the engine 10 to detect the position of the crankshaft. These sensors are connected to an engine control unit (hereinafter referred to as "ECU") 60, which will be described later. Also connected to the ECU 60 are various sensors such as an accelerator pedal sensor 62 that detects the amount of depression of the accelerator pedal, that is, the opening degree of the accelerator pedal, and a water temperature sensor that detects the temperature of the cooling water of the engine 10.

The crankshaft 15 of the engine 10 is equipped with a continuously variable transmission 30 that converts and outputs the driving force from the engine 10 via a torque converter 21 that has a clutch function and a torque amplification function, and a second clutch 27. It is connected.

The torque converter 21 mainly includes a pump impeller 22, a turbine runner 23, and a stator 24. A pump impeller 22 connected to the crankshaft 15 generates a flow of oil, and a turbine runner 23 disposed opposite the pump impeller 22 receives power from the engine 10 via the oil to drive an output shaft. The stator 24 located between the two rectifies the exhaust flow (return) from the turbine runner 23 and returns it to the pump impeller 22, thereby generating a torque amplification effect.

Further, the torque converter 21 includes a lock-up clutch 25 that directly connects an input and an output. The torque converter 21 amplifies and transmits the driving force of the engine 10 with torque when the lockup clutch 25 is not engaged (non-lockup state), and transmits the torque amplified when the lockup clutch 25 is engaged (non-lockup state). time) directly transmits the driving force of the engine 10.

A second clutch 27 is provided between the torque converter 21 and the continuously variable transmission 30 to connect and disconnect the driving force transmitted from the engine 10 to the continuously variable transmission 30. The engagement/disengagement of the second clutch 27 is controlled by a transmission control unit (hereinafter referred to as "TCU") 50 and a valve body (control valve) 80, which will be described later. Note that the configuration may be such that the second clutch 27 is not provided.

The continuously variable transmission 30 includes a primary shaft 32 connected to a turbine shaft (output shaft) 26 of the torque converter 21 via a second clutch 27, and a secondary shaft 37 disposed parallel to the primary shaft 32. have.

A primary pulley 34 is provided on the primary shaft 32. The primary pulley 34 has a fixed sheave 34a joined to the primary shaft 32, and a movable sheave 34b mounted so as to be slidable in the axial direction of the primary shaft 32, facing the fixed sheave 34a. It is configured such that the cone surface spacing of the sheaves 34a and 34b, that is, the pulley groove width, can be changed. On the other hand, the secondary shaft 37 is provided with a secondary pulley 35 . The secondary pulley 35 has a fixed sheave 35a joined to the secondary shaft 37, and a movable sheave 35b mounted so as to be slidable in the axial direction of the secondary shaft 37, facing the fixed sheave 35a. It is configured so that the width can be changed.

A chain 36 for transmitting driving force is stretched between the primary pulley 34 and the secondary pulley 35. By changing the groove widths of the primary pulley 34 and the secondary pulley 35 and changing the ratio of the winding diameter of the chain 36 to each pulley 34, 35 (pulley ratio), the gear ratio is changed steplessly. Here, if the winding diameter of the chain 36 around the primary pulley 34 is Rp, and the winding diameter around the secondary pulley 35 is Rs, the speed ratio i is expressed as i=Rs/Rp. Therefore, the gear ratio i is determined by dividing the primary pulley rotation speed Np by the secondary pulley rotation speed Ns (i=Np/Ns).

Here, a hydraulic chamber 34c is formed in the primary pulley 34 (movable sheave 34b). On the other hand, a hydraulic chamber 35c is formed in the secondary pulley 35 (movable sheave 35b). The groove widths of the primary pulley 34 and the secondary pulley 35 can be set and changed by adjusting the primary hydraulic pressure introduced into the hydraulic chamber 34c of the primary pulley 34 and the secondary hydraulic pressure introduced into the hydraulic chamber 35c of the secondary pulley 35. be done.

A forward/reverse switching mechanism 40 is connected to the secondary shaft 37 for switching between forward and reverse rotation of the drive wheels (forward and reverse movement of the vehicle). The forward/reverse switching mechanism 40 mainly includes a double pinion planetary gear train 41, a forward clutch 42, and a reverse brake 43. The forward/reverse switching mechanism 40 is configured to be able to switch the transmission path of the engine driving force by controlling the respective states of the forward clutch 42 and the reverse brake 43.

More specifically, when the shift lever 55 is operated and the D range (forward travel range) is selected, the rotation of the secondary shaft 37 is stopped by engaging the forward clutch 42 and releasing the reverse brake 43. The power is transmitted directly to the drive wheels, allowing the vehicle to move forward. Further, when the R range (reverse travel range) is selected, the forward clutch 42 is released and the reverse brake 43 is engaged, thereby operating the planetary gear train 41 and reversing the rotation direction of the secondary shaft 37. This makes it possible to drive the vehicle backwards.

Note that when the N range or the P range is selected, by releasing the forward clutch 42 and the reverse brake 43, the secondary shaft 37 and the drive wheels are separated (transmission of engine driving force is cut off), and the drive It becomes a neutral state where no power is transmitted to the wheels.

Using the forward clutch 42 and reverse brake 43, coasting control is performed. That is, during coasting control, the forward clutch 42 and the reverse brake 43 are released, and the engine 10 and continuously variable transmission 30 are disconnected from the drive wheels. That is, the forward clutch 42 (and the reverse brake 43) functions as a clutch described in the claims. Note that the operations of the forward clutch 42 and the reverse brake 43 are controlled by a TCU 50 and a valve body (control valve) 80, which will be described later.

The hydraulic pressure for shifting the continuously variable transmission 30, that is, the above-mentioned primary hydraulic pressure and secondary hydraulic pressure, is controlled by a valve body (control valve) 80. The valve body 80 uses a spool valve and a solenoid valve (electromagnetic valve) to operate the spool valve to open and close an oil passage formed within the valve body 80, thereby controlling the hydraulic pressure discharged from an oil pump (not shown). It is adjusted and supplied to the hydraulic chamber 34c of the primary pulley 34 and the hydraulic chamber 35c of the secondary pulley 35. The valve body 80 also supplies hydraulic pressure to the forward/reverse switching mechanism 40 and the like.

Shift control of the continuously variable transmission 30 is executed by the TCU 50. That is, the TCU 50 adjusts the hydraulic pressure supplied to the hydraulic chamber 34c of the primary pulley 34 and the hydraulic chamber 35c of the secondary pulley 35 by controlling the drive of the solenoid valve (electromagnetic valve) that constitutes the valve body 80 described above. , changes the gear ratio of the continuously variable transmission 30. Further, the TCU 50 controls the drive of the forward clutch solenoid 80a that constitutes the above-mentioned valve body 80, thereby adjusting the amount of oil supplied to/discharging the forward clutch 42, and engages/disengages the forward clutch 42. Similarly, the TCU 50 controls the drive of the reverse brake solenoid 80b that constitutes the valve body 80 to adjust the amount of oil supplied to/discharged from the reverse brake 43, thereby engaging/releasing the reverse brake 43.

The TCU 50 includes an oil temperature sensor 56 that detects the temperature of the oil in the continuously variable transmission 30, a primary pulley rotation sensor 57 that detects the rotation speed of the primary pulley 34 (primary shaft 32), and a secondary pulley 35 (secondary shaft 37). ) is connected to a secondary pulley rotation sensor 58 that detects the rotation speed of the pulley. Note that the secondary pulley rotation sensor 58 (or the primary pulley rotation sensor 57) corresponds to detection means described in the claims. The TCU 50 is also communicably connected to an ECU 60 that comprehensively controls the engine 10, a vehicle dynamics control unit (hereinafter referred to as "VDCU") 70, etc. via a CAN (Controller Area Network) 100, for example. has been done.

In the ECU 60, the cylinder is determined from the output of the above-mentioned cam angle sensor, and the engine rotation speed is determined from the change in the rotational position of the crankshaft detected by the output of the crank angle sensor. Furthermore, the ECU 60 acquires various information such as intake air amount, accelerator pedal opening, air-fuel ratio of air-fuel mixture, and water temperature based on detection signals input from the various sensors described above. The ECU 60 comprehensively controls the engine 10 by controlling the fuel injection amount, ignition timing, and various devices such as the throttle valve 13 based on the acquired various information. The ECU 60 stops fuel injection to the engine 10 (performs fuel cut) during coasting control. That is, the engine 10 is stopped.

Furthermore, the ECU 60 calculates the engine shaft torque (output torque) of the engine 10 based on the intake air amount detected by the air flow meter 61. Then, the ECU 60 transmits information such as the engine rotation speed, engine shaft torque, and accelerator pedal opening degree to the TCU 50 via the CAN 100.

The VDCU 70 is connected to a brake switch 71 that detects whether a brake pedal is depressed or not, and a brake fluid pressure sensor 72 that detects master cylinder pressure (brake oil pressure) of a brake actuator 74. Also connected to the VDCU 70 are wheel speed sensors 73 and the like that detect the rotational speed (vehicle speed) of each wheel of the vehicle.

The VDCU 70 brakes the vehicle by driving a brake actuator 74 according to the amount of operation (depression amount) of the brake pedal, and also detects vehicle behavior using various sensors (for example, a wheel speed sensor 73, a steering angle sensor, an acceleration sensor, a yaw rate sensor, etc.). ), and by controlling the brakes using automatic pressurization and controlling the torque of the engine 10, skidding is suppressed and vehicle stability is ensured when turning. In addition, the VDCU70 prevents wheel locking that occurs when braking suddenly or on slippery roads, and maintains an appropriate slip ratio for each wheel, ensuring directional stability and steering performance during braking, and ensuring optimum Anti-lock brake function (ABS function) that obtains strong braking force, and traction that suppresses the spinning of the drive wheels caused by slippery roads or excessive driving force, ensuring vehicle stability and acceleration when starting or accelerating. It also has a control function (TCS function).

The VDCU 70 transmits braking information (brake operation information) such as the detected brake switch 71 and brake fluid pressure, wheel speed (vehicle speed), etc. to the TCU 50 and the ECU 60 via the CAN 100.

The TCU 50 includes a microprocessor that performs calculations, an EEPROM that stores programs for causing the microprocessor to execute various processes, a RAM that stores various data such as calculation results, a backup RAM whose storage contents are retained by a battery, It is configured with an input/output I/F, etc. The TCU 50 receives the above-mentioned brake operation information, vehicle speed information, accelerator operation information, etc. from the ECU 60 and the VDCU 70 via the CAN 100.

The TCU 50 automatically changes the gear ratio steplessly according to the driving state of the vehicle (eg, accelerator pedal opening, vehicle speed, etc.) according to the gear shift map. Note that a shift map corresponding to the automatic shift mode is stored in an EEPROM or the like within the TCU 50.

In particular, the TCU 50 has a function of reducing shocks caused by re-engagement of the forward clutch 42 when returning from coasting to normal running. Therefore, the TCU 50 functionally includes a coasting control section 51. In the TCU 50, a program stored in an EEPROM or the like is executed by a microprocessor, thereby realizing the functions of the coasting control section 51.

The coasting control unit 51 controls when predetermined coasting control conditions (for example, the vehicle speed is a predetermined speed or higher, the accelerator pedal is not depressed, and the brake pedal is not depressed, etc.) are satisfied. Then, the forward clutch 42 (and the reverse brake 43) is released, and coasting control is executed to stop the fuel supply to the engine 10 (send fuel cut request information to the ECU 60). Furthermore, the coasting control section 51 releases the second clutch 27 when a predetermined coasting control condition is satisfied. That is, the coasting control section 51 functions as coasting control means described in the claims.

When the coasting state occurs, the engine 10 is stopped and the forward clutch 42 (and reverse brake 43) and second clutch 27 are released, so that the continuously variable transmission 30 (variator) is The rotation speed gradually decreases. Therefore, when the rotation speed of the continuously variable transmission 30 becomes less than the first predetermined rotation speed during execution of coasting control, the coasting control unit 51 gradually engages the forward clutch 42 (loosely engages the forward clutch 42). )do. That is, the forward clutch 42 is gradually engaged, and the rotation speed of the continuously variable transmission 30 (variator) is increased. Then, if the rotation speed of the continuously variable transmission 30 becomes equal to or higher than the second predetermined rotation speed, which is higher than the first predetermined rotation speed, the coasting control section 51 quickly activates the forward clutch 42. release.

Here, from the viewpoint of preventing frequent engagement and disengagement of the forward clutch 42, the second predetermined rotation speed is set higher than the first predetermined rotation speed by a predetermined value or more (that is, hysteresis is not provided). It is preferable that

Each of the first predetermined rotation speed and the second predetermined rotation speed is set according to the vehicle speed, and increases as the vehicle speed increases. Note that the first predetermined rotation speed and the second predetermined rotation speed are set to be lower than or equal to the vehicle speed (the rotation speed equivalent to the vehicle speed of the secondary pulley 35 (or primary pulley 34)). The first predetermined rotation speed and the second predetermined rotation speed can be set, for example, based on a map that defines the relationship between the vehicle speed, the first predetermined rotation speed, and the second predetermined rotation speed. . Alternatively, the first predetermined rotation speed and the second predetermined rotation speed may be determined using an arithmetic expression (an arithmetic expression using the vehicle speed as a variable).

Further, since the shock at the time of clutch engagement can also change depending on the gear ratio and oil temperature of the continuously variable transmission 30, the first predetermined rotation speed and the second predetermined rotation speed are different from each other of the continuously variable transmission 30. It is preferable to correct according to the gear ratio and/or the oil temperature. More specifically, for example, the setting is such that the closer the gear ratio is to the low side, the smaller the difference between the first predetermined rotation speed, the second predetermined rotation speed, and the vehicle speed (revolution speed equivalent to the vehicle speed) becomes smaller. It is preferable to do so. Further, it is preferable that the difference between the first predetermined number of rotations, the second predetermined number of rotations, and the vehicle speed (the number of rotations corresponding to the vehicle speed) become smaller as the oil temperature increases.

Next, the operation of the coasting control device 1 will be explained with reference to FIG. 2. FIG. 2 is a flowchart showing a processing procedure of coasting control (coasting control) by the coasting control device 1. This process is repeatedly executed in the TCU 50 at predetermined time intervals (for example, every 10 ms).

First, in step S100, for example, vehicle speed information, accelerator operation information, brake operation information, etc. are read. Then, in the following step S102, based on the information read in step S100, it is determined whether the coasting control execution conditions are satisfied (that is, the vehicle speed is a predetermined value or more, the accelerator pedal is not depressed, , and whether the brake pedal is not depressed). Here, if the coasting control execution conditions are satisfied, the process moves to step S104. On the other hand, if the coasting control execution conditions are not satisfied, the process exits once.

In step S104, coasting control is executed. That is, forward clutch 42 and second clutch 27 are released, and fuel supply to engine 10 is stopped.

Subsequently, in step S106, the rotation speed of the continuously variable transmission 30 (that is, the rotation speed of the secondary pulley 35 (or the primary pulley 34)) is read.

Next, in step S108, a determination is made as to whether the rotation speed of the continuously variable transmission 30 is less than a first predetermined rotation speed. Here, if the rotation speed of the continuously variable transmission 30 is equal to or higher than the first predetermined rotation speed, the process moves to step S116. On the other hand, when the rotation speed of the continuously variable transmission 30 is less than the first predetermined rotation speed, the process moves to step S110.

In step S110, forward clutch 42 is gradually engaged. Therefore, the continuously variable transmission 30 (variator) is rotated by the input from the driving wheels, and the rotational speed increases.

Next, in step S112, a determination is made as to whether the rotation speed of the continuously variable transmission 30 is equal to or higher than a second predetermined rotation speed. Here, if the rotation speed of the continuously variable transmission 30 is less than the second predetermined rotation speed, the process moves to step S116. On the other hand, when the rotation speed of the continuously variable transmission 30 is equal to or higher than the second predetermined rotation speed, the process moves to step S114.

In step S114, forward clutch 42 is released. After that, the process moves to step S116.

In step S116, a determination is made as to whether a predetermined coasting control termination condition is satisfied (or whether a predetermined coasting control execution condition is no longer satisfied). Here, if the coasting control termination condition is not satisfied, the process returns to step S106, and the processes of steps S106 to S116 described above are repeatedly executed until the coasting control termination condition is satisfied. On the other hand, when the coasting control termination condition is satisfied, the coasting control is stopped in step S118 and normal running is resumed (that is, the engine 10 is driven and the forward clutch 42 and the second clutch 27 are engaged). be done. Thereafter, the process exits from this process.

As described above in detail, according to the present embodiment, coasting control is executed in which the engine 10 is stopped and the forward clutch 42 is released when the predetermined coasting control conditions are satisfied. Ru. If the rotational speed of the continuously variable transmission 30 becomes less than the first predetermined rotational speed during the execution of the coasting control, the forward clutch 42 is gradually engaged, and then the continuously variable transmission 30 is rotated. When the rotational speed becomes equal to or higher than the second predetermined rotational speed, the forward clutch 42 is released. Therefore, during coasting, the number of revolutions of the continuously variable transmission 30 is prevented from decreasing too much, that is, the difference between the number of revolutions of the continuously variable transmission 30 and the vehicle speed (the number of revolutions corresponding to the vehicle speed) is not increased too much. can be controlled. As a result, it is possible to reduce shocks caused by re-engagement of the forward clutch 42 when returning from coasting to normal running. In other words, it is possible to achieve both improved fuel efficiency and drivability (shock reduction).

According to this embodiment, the second predetermined rotation speed is set higher than the first predetermined rotation speed by a predetermined value or more. Therefore, the rotation speed of the continuously variable transmission 30 can be maintained between the first predetermined rotation speed and the second predetermined rotation speed. Further, by providing a hysteresis of a predetermined value or more between the second predetermined rotation speed and the first predetermined rotation speed, it is possible to prevent frequent engagement and disconnection of the forward clutch 42.

According to this embodiment, each of the first predetermined rotation speed and the second predetermined rotation speed is set to increase as the vehicle speed increases. Therefore, the difference between each of the first predetermined rotation speed and the second predetermined rotation speed and the vehicle speed (revolution speed equivalent to the vehicle speed) can be appropriately controlled, and the shock etc. when re-engaging the forward clutch 42 can be appropriately controlled. It becomes possible to reduce the amount accurately.

According to this embodiment, each of the first predetermined rotation speed and the second predetermined rotation speed is corrected according to the gear ratio of the continuously variable transmission 30 and/or the oil temperature. Therefore, the shock and the like when the forward clutch 42 is re-engaged is more appropriately reduced by taking into account the gear ratio of the continuously variable transmission 30 and/or the oil temperature that may affect the shock and the like when the clutch is re-engaged. becomes possible.

Furthermore, according to the present embodiment, the second clutch 27 is released when a predetermined coasting control condition is satisfied. Therefore, when the forward clutch 42 is engaged and the continuously variable transmission 30 (variator) is rotated from the drive wheel side, it is possible to prevent the engine 10 from rotating along with it (reduce friction).

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. For example, in the above embodiment, the second clutch 27 is arranged upstream of the primary pulley 34 and the forward/reverse switching mechanism 40 is arranged downstream of the secondary pulley 35; It is also possible to arrange the second clutch 27 on the upstream side and the second clutch 27 on the downstream side of the secondary pulley 35. That is, the forward/reverse switching mechanism 40 and the second clutch 27 may be replaced. Further, a configuration may be adopted in which the second clutch 27 interposed between the engine 10 (driving power source) and the continuously variable transmission 30 is not provided.

In the above embodiment, hydraulic types are used as the forward clutch 42 and the reverse brake 43, but electromagnetic types may also be used, for example.

In the above embodiment, the present invention is applied to a chain type continuously variable transmission (CVT), but instead of the chain type continuously variable transmission, for example, a belt type continuously variable transmission or a toroidal type continuously variable transmission can be used. It can also be applied to transmissions, etc.

In the above embodiment, the TCU 50 determines whether to perform coasting control, but the ECU 60 may determine whether to perform the coasting control, and the determination result may be transmitted to the TCU 50 via the CAN 100. Further, in the above embodiment, the ECU 60 that controls the engine 10 and the TCU 50 that controls the continuously variable transmission 30 and the like are configured as separate hardware, but they may be configured as a single piece of hardware.

1 Coastal running control device 10 Engine 21 Torque converter 27 Second clutch 30 Continuously variable transmission 34 Primary pulley 35 Secondary pulley 36 Chain 40 Forward/forward switching mechanism 41 Planetary gear train 42 Forward clutch 43 Reverse brake 50 TCU
51 Coasting control section 55 Shift lever 56 Oil temperature sensor 57 Primary pulley rotation sensor 58 Secondary pulley rotation sensor 60 ECU
70VDCU
71 Brake switch 72 Brake fluid pressure sensor 73 Wheel speed sensor 74 Brake actuator 80 Valve body (control valve)
100 CAN

Claims (5)

a clutch that is provided between a continuously variable transmission that converts and outputs the driving force of an engine and the driving wheels of the vehicle, and that connects and disconnects the driving force that is transmitted from the continuously variable transmission to the driving wheels of the vehicle;
Detection means for detecting the rotation speed of the continuously variable transmission;
coasting control means for executing coasting control that stops the engine and releases the clutch when a predetermined coasting control condition is satisfied;
The coasting control means gradually engages the clutch when the number of revolutions of the continuously variable transmission becomes less than a first predetermined number of revolutions during execution of the coasting control, and then the coasting control means gradually engages the clutch. When the rotational speed of the step-change transmission becomes equal to or higher than a second predetermined rotational speed that is higher than the first predetermined rotational speed, the clutch is released ;
The coasting control device is characterized in that the first predetermined rotation speed and the second predetermined rotation speed are set to increase as the vehicle speed increases . The coasting control device according to claim 1, wherein the second predetermined rotation speed is set higher than the first predetermined rotation speed by a predetermined value or more. 2. The first predetermined rotation speed and the second predetermined rotation speed are corrected according to a gear ratio and/or an oil temperature of the continuously variable transmission. The coasting control device described in . The coasting control device according to any one of claims 1 to 3 , wherein the clutch is a forward clutch that constitutes a forward/reverse switching mechanism that switches between forward and reverse rotation of the drive wheels. Further comprising a second clutch that is interposed between the engine and the continuously variable transmission and connects and disconnects the driving force transmitted from the engine to the continuously variable transmission,
The coasting control device according to any one of claims 1 to 4 , wherein the coasting control means releases the second clutch when a predetermined coasting control condition is satisfied. .

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