Continuously variable transmission control device

Abstract

To provide a control device of a continuously variable transmission which makes it possible to estimate motor torque even though the motor torque cannot be acquired from another control unit via a communication line in the control device of the continuously variable transmission which is installed on a hybrid vehicle.SOLUTION: A TCU 74 obtains an engine rotation speed and a vehicle acceleration of an engine 10 from a vehicle speed acquired from a VDCU 76 via a CAN 100 and then obtains motor torque from an equation of motion of a hybrid vehicle by using the engine rotation speed, the vehicle acceleration and engine torque acquired from an ECU 71 via the CAN 100 if the motor torque cannot be acquired from an HEV-CU 70 via the CAN 100.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a continuously variable transmission, and more particularly to a control device for a continuously variable transmission mounted on a hybrid vehicle. [Background technology]

[0002] BACKGROUND ART In recent years, hybrid vehicles that can effectively improve the fuel consumption rate (fuel economy) of a vehicle by using both an engine and an electric motor have been widely put into practical use.

[0003] In addition, to further improve fuel efficiency, hybrid vehicles have been proposed that perform coasting control (coasting control) when the accelerator pedal is released while driving and the vehicle is coasting (coasting), for example by releasing a clutch provided between the engine and the drive wheels, thereby separating the engine from the drive system and stopping the supply of fuel to the engine (fuel cut) (see, for example, Patent Documents 1 and 2).

[0004] In a hybrid vehicle equipped with a continuously variable transmission, for example, in a failure mode in which an abnormality occurs in the continuously variable transmission during coasting deceleration, causing a sudden deceleration, the future deceleration is predicted, and if the predicted deceleration becomes larger than a predetermined threshold, the gear ratio of the continuously variable transmission is fixed (kept constant) to avoid a sudden deceleration. It is possible that . [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-131292 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-131273 Summary of the Invention [Problem to be solved by the invention]

[0006] For example, in a control system in which a transmission control unit (TCU) that controls a continuously variable transmission, an engine control unit (ECU) that controls the engine, a motor control unit (MCU or HEV-CU) that controls an electric motor, and a vehicle dynamics control unit (VDCU) that controls vehicle behavior are connected to each other so that they can communicate with each other via a communication line such as a CAN (Controller Area Network), if the above-mentioned predicted deceleration is calculated in the TCU based on, for example, the target primary pulley rotation speed of the continuously variable transmission, the actual engine torque obtained from the ECU via the CAN, the actual motor torque obtained from the MCU or HEV-CU via the CAN, and the vehicle speed obtained from the VDCU via the CAN, if it becomes impossible to obtain the actual motor torque from the MCU or HEV-CU via the CAN, for example, the predicted deceleration will no longer be able to be calculated in the TCU.

[0007] In the case of the system configuration described above, actual motor torque information from the MCU or HEV-CU (other control unit) obtained via CAN is used to calculate the predicted deceleration, so a fault response is required in the event that actual motor torque information cannot be obtained from the MCU or HEV-CU (other control unit) via CAN.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a continuously variable transmission control device mounted on a hybrid vehicle that is capable of estimating motor torque even when it is not possible to obtain motor torque from another control unit via a communication line. [Means for solving the problem]

[0009] The continuously variable transmission control device of the present invention is mounted on a hybrid vehicle having an engine and an electric motor capable of transmitting power between the engine's crankshaft, and is a continuously variable transmission control device that continuously converts at least the engine torque of the engine. The control device has an engine control unit that controls the engine, a motor control unit that controls the electric motor, and a vehicle control unit that controls the vehicle behavior of the hybrid vehicle, and a transmission control unit that is communicatively connected to each other via communication lines and controls the continuously variable transmission. When the transmission control unit cannot obtain motor torque from the motor control unit via the communication line, it determines the engine rotation speed and vehicle acceleration of the engine from the vehicle speed obtained from the vehicle control unit via the communication line, and determines the motor torque from the equation of motion of the hybrid vehicle using the engine rotation speed, vehicle acceleration, and engine torque obtained from the engine control unit via the communication line.

[0010] According to the control device for a continuously variable transmission of the present invention, when motor torque cannot be obtained from the motor control unit via the communication line, the engine rotation speed and vehicle acceleration of the engine are calculated from the vehicle speed obtained from the vehicle control unit via the communication line, and motor torque is calculated from the equation of motion of the hybrid vehicle using the engine rotation speed, vehicle acceleration, and engine torque obtained from the engine control unit via the communication line. Therefore, even when motor torque cannot be obtained from another control unit by communication via the communication line, motor torque can be estimated. [Effects of the Invention]

[0011] According to the present invention, in a control device for a continuously variable transmission mounted on a hybrid vehicle, it is possible to estimate motor torque even when it is not possible to obtain motor torque from another control unit (motor control unit) via a communication line. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram showing a configuration of a control device for a continuously variable transmission according to an embodiment, and a main part of a hybrid vehicle to which the control device is applied; [Figure 2] 4 is a flowchart showing a processing procedure of sudden deceleration avoidance control (motor torque calculation processing) during coasting performed by the control device for the continuously variable transmission according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be designated by the same reference numerals. In addition, the same elements will be designated by the same reference numerals in each drawing, and redundant explanations will be omitted.

[0014] First, a description will be given of the configuration of a control device 1 for a continuously variable transmission according to an embodiment and a main part of a hybrid vehicle to which the control device 1 is applied, using Fig. 1. Fig. 1 is a block diagram showing the configuration of the control device 1 for a continuously variable transmission and a main part of a hybrid vehicle to which the control device 1 is applied.

[0015] The engine 10 may be of any type, but may be, for example, a horizontally opposed, direct-injection, four-cylinder gasoline engine. In the engine 10, air drawn in through an air cleaner (not shown) is throttled by an electronically controlled throttle valve provided in the intake pipe, passes through an intake manifold, and is drawn into each cylinder of the engine 10. The amount of air drawn in through the air cleaner is detected by an air flow meter 83. The throttle valve is further provided with a throttle opening sensor that detects the opening of the throttle valve. Each cylinder is equipped with an injector that injects fuel. Each cylinder is also equipped with a spark plug that ignites the air-fuel mixture and a built-in igniter coil that applies high voltage to the spark plug. In each cylinder of the engine 10, the air-fuel mixture, consisting of the drawn air and the fuel injected by the injector, is ignited by the spark plug and combusted. The resulting exhaust gas is discharged through an exhaust pipe.

[0016] In addition to the air flow meter 83 and throttle opening sensor described above, a cam angle sensor for identifying the cylinders of the engine 10 is attached near the camshaft of the engine 10. Also, a crank angle sensor 84 for detecting the rotational position (rotational speed) of the crankshaft 15 is attached near the crankshaft 15 of the engine 10. These sensors are connected to an engine control unit (hereinafter referred to as "ECU") 71, which will be described later. The ECU 71 is also connected to various sensors, such as a water temperature sensor for detecting the temperature of the cooling water for the engine 10.

[0017] A continuously variable transmission 50 that converts and outputs the driving force from the engine 10 is connected to the crankshaft 15 of the engine 10 via a torque converter 20 that has a clutch function and a torque amplification function, and a forward / reverse switching mechanism 30.

[0018] The torque converter 20 is mainly composed of a pump impeller 21, a turbine runner 22, and a stator 23. The pump impeller 21 connected to the crankshaft 15 generates a flow of oil, and the turbine runner 22, which is disposed opposite the pump impeller 21, receives power from the engine 10 via the oil to drive a turbine shaft 25. The stator 23, located between the two, rectifies the discharge flow (return) from the turbine runner 22 and returns it to the pump impeller 21, thereby generating torque amplification.

[0019] Torque converter 20 also has a lock-up clutch 24 that directly couples the input and output. When lock-up clutch 24 is not engaged (in a non-lock-up state), torque converter 20 amplifies the driving force of engine 10 and transmits it to continuously variable transmission 50, and when lock-up clutch 24 is engaged (in a lock-up state), torque converter 20 directly transmits the driving force of engine 10 to continuously variable transmission 50. The rotation speed (turbine rotation speed) of turbine runner 22 that constitutes torque converter 20 is detected by a turbine rotation sensor 87. The detected turbine rotation speed is output to a transmission control unit (hereinafter referred to as "TCU") 74, which will be described later.

[0020] The forward / reverse switching mechanism 30 switches between forward and reverse rotation of the drive wheels (forward and reverse movement of the vehicle). The forward / reverse switching mechanism 30 mainly includes a double-pinion planetary gear train 31, a forward clutch 32, and a reverse brake 33. The forward / reverse switching mechanism 30 is configured to be able to switch the transmission path of the engine driving force by controlling the respective states of the forward clutch 32 and the reverse brake 33.

[0021] More specifically, when the D range (forward travel range) is selected, the forward clutch 32 is engaged and the reverse brake 33 is disengaged, thereby transmitting the rotation of the turbine shaft 25 directly to the primary shaft 51, which will be described later, and allowing the vehicle to travel forward. When the R range (reverse travel range) is selected, the forward clutch 32 is disengaged and the reverse brake 33 is engaged, thereby operating the planetary gear train 31 and reversing the rotation direction of the primary shaft 51, allowing the vehicle to travel backward. When the N range or P range is selected, the forward clutch 32 and the reverse brake 33 are disengaged, thereby separating the turbine shaft 25 from the primary shaft 51 (interrupting the transmission of engine driving force), and the forward / reverse switching mechanism 30 is placed in a neutral state in which it does not transmit power to the primary shaft 51.

[0022] The operation (engagement and release) of the forward clutch 32 and the reverse brake 33 is controlled by a TCU 74 and a control valve 75, which will be described later.

[0023] The continuously variable transmission 50 has a primary shaft 51 connected to the turbine shaft 25 of the torque converter 20 via the forward / reverse switching mechanism 30 , and a secondary shaft 55 disposed in parallel to the primary shaft 51 .

[0024] A primary pulley 52 is provided on the primary shaft 51. The primary pulley 52 has a fixed sheave 52a joined to the primary shaft 51 and a movable sheave 52b attached to the primary shaft 51 so as to be slidable in the axial direction of the primary shaft 51, facing the fixed sheave 52a, and is configured so that the cone face spacing between the sheaves 52a, 52b, i.e., the pulley groove width, can be changed. Meanwhile, a secondary pulley 53 is provided on the secondary shaft 55. The secondary pulley 53 has a fixed sheave 53a joined to the secondary shaft 55 and a movable sheave 53b attached to the secondary shaft 55 so as to be slidable in the axial direction of the secondary shaft 55, facing the fixed sheave 53a, and is configured so that the pulley groove width can be changed.

[0025] A chain 54 for transmitting driving force is wound around the primary pulley 52 and the secondary pulley 53. The gear ratio is continuously changed by changing the groove width of the primary pulley 52 and the secondary pulley 53 to change the ratio of the winding diameter of the chain 54 to each of the pulleys 52, 53 (pulley ratio). Here, if the winding diameter of the chain 54 around the primary pulley 52 is Rp and the winding diameter around the secondary pulley 53 is Rs, the gear ratio i is expressed as i = Rs / Rp. Therefore, the gear ratio i can be calculated by dividing the primary pulley rotation speed Np by the secondary pulley rotation speed Ns (i = Np / Ns).

[0026] Here, a hydraulic chamber 52c is formed on the back side of the movable sheave 52b of the primary pulley 52. ​​Meanwhile, a hydraulic chamber 53c is formed on the back side of the movable sheave 53b of the secondary pulley 53. The groove widths of the primary pulley 52 and the secondary pulley 53 are set and changed by adjusting the primary hydraulic pressure introduced into the hydraulic chamber 52c of the primary pulley 52 and the secondary hydraulic pressure introduced into the hydraulic chamber 53c of the secondary pulley 53.

[0027] An electric motor 40 is connected to the primary shaft 51 of the continuously variable transmission 50 so as to be able to transmit torque. The electric motor 40 is, for example, a three-phase AC synchronous motor. In this embodiment, the electric motor 40 is of a type that uses a permanent magnet in the rotor and a coil in the stator. The electric motor 40 is a so-called motor generator that operates mainly as a driving force source for driving the vehicle and also functions as a generator during regeneration, etc. Note that the electric motor 40 may also use a coil in the rotor and a permanent magnet in the stator. Furthermore, instead of an AC synchronous motor, an AC induction motor, a DC motor, or the like may also be used as the electric motor 40.

[0028] The continuously variable transmission 50 is provided with an oil pump 35 for pressure-feeding oil used in the continuously variable transmission 50, the forward / reverse switching mechanism 30, the electric motor 40, etc. The oil pump 35 draws oil stored in an oil pan (not shown), increases the pressure, and pressure-feeds the oil to the continuously variable transmission 50, the forward / reverse switching mechanism 30, the electric motor 40, etc. The oil pump 35 may be, for example, a trochoid pump or a vane pump. A drive shaft of the oil pump 35 is connected to the turbine shaft 25 and the primary shaft 51, for example, via a chain or the like, so as to be able to transmit torque. In other words, the oil pump 35 is configured to be drivable by the engine 10 and the electric motor 40, respectively.

[0029] A secondary shaft 55 of the continuously variable transmission 50 is connected to a counter shaft 60 via a reduction gear (secondary reduction gear) 59 consisting of a pair of gears (reduction drive gear, reduction driven gear), and the driving force converted by the continuously variable transmission 50 is transmitted to the counter shaft 60 via the reduction gear 59. An output clutch 61 and a parking gear 62 that constitutes a parking mechanism are attached to the counter shaft 60.

[0030] The output clutch 61 is provided between the secondary shaft 55 of the continuously variable transmission 50 and the drive wheels, and interrupts torque transmission between the continuously variable transmission 50 (engine 10 and electric motor 40) and the drive wheels. For example, when the engine 10 rotates the electric motor 40 to generate electricity while the vehicle is stopped, the output clutch 61 is released to separate the engine 10 and the electric motor 40 from the wheels. Therefore, the output clutch 61 is engaged at other times (for example, while the vehicle is running). The output clutch 61 is controlled (engaged and released) by the TCU 74, which will be described later. If the vehicle is configured (specified) not to generate electricity while stopped, the output clutch 61 may be omitted.

[0031] The counter shaft 60 is connected to a front drive shaft 66 via a counter gear 63 consisting of a pair of gears (counter drive gear and counter driven gear). The driving force transmitted to the counter shaft 60 is transmitted to a front differential (hereinafter also referred to as "front differential") 67 via the counter gear 63 and the front drive shaft 66. The front differential 67 is, for example, a bevel gear type differential device. The driving force from the front differential 67 is transmitted to the left front wheel via the left front wheel drive shaft and to the right front wheel via the right front wheel drive shaft.

[0032] Meanwhile, a transfer clutch 64 is provided downstream of the counter gear 63 (counter drive gear) on the counter shaft 60, and adjusts the driving force transmitted to a rear differential (hereinafter also referred to as "rear differential") 69. The fastening force (i.e., torque distribution rate to the rear wheels) of the transfer clutch 64 is controlled in accordance with the drive state of the four wheels (for example, slip state of the front wheels), engine torque, etc. Therefore, the driving force transmitted to the counter shaft 60 is distributed in accordance with the fastening force of the transfer clutch 64, and is also transmitted to the rear wheels.

[0033] More specifically, the rear end of the countershaft 60 is connected to a propeller shaft 68 extending toward the rear of the vehicle via a transfer gear 65 consisting of a pair of gears (transfer drive gear, transfer driven gear). Therefore, the driving force transmitted to the countershaft 60 and adjusted (distributed) by the transfer clutch 64 is transmitted from the transfer gear 65 (transfer driven gear) to the rear differential 69 via the propeller shaft 68.

[0034] A left rear wheel drive shaft and a right rear wheel drive shaft are connected to the rear differential 69. Driving force from the rear differential 69 is transmitted to the left rear wheel via the left rear wheel drive shaft and to the right rear wheel via the right rear wheel drive shaft.

[0035] As configured as described above, this hybrid vehicle can drive the wheels (vehicle) using two power sources: engine 10 and electric motor 40. In addition, deceleration regeneration and power generation can be performed using electric motor 40. Furthermore, with the driving force transmission system configured as described above, when the shift lever is operated to D range, for example, forward clutch 32 is engaged and the engine driving force (and the driving force of electric motor 40) is input to primary shaft 51 of continuously variable transmission 50. The driving force converted by continuously variable transmission 50 is output from secondary shaft 55 and transmitted to front drive shaft 66 via reduction gear 59, counter shaft 60, and counter gear 63. The driving force is then distributed to the left and right by front differential 67 and transmitted to the left and right front wheels.

[0036] Meanwhile, part of the driving force transmitted to the countershaft 60 is transmitted to a propeller shaft 68 via a transfer clutch 64 and a transfer gear 65. When a predetermined clutch torque is applied to the transfer clutch 64, the driving force distributed in accordance with the clutch torque is output to the propeller shaft 68. The driving force is then transmitted to the rear wheels via a rear differential 69.

[0037] The engine 10, electric motor 40, and continuously variable transmission 50, which are the vehicle's driving force sources, are comprehensively controlled by a control system comprising a hybrid vehicle control unit (hereinafter referred to as "HEV-CU") 70 (corresponding to the motor control unit described in the claims), an ECU 71, a power control unit (hereinafter referred to as "PCU") 72, a TCU 74, a vehicle dynamics control unit (hereinafter referred to as "VDCU") 76 (corresponding to the vehicle control unit described in the claims), and the like.

[0038] Each of the HEV-CU70, ECU71, PCU72, TCU74, and VDCU76 is configured with a microprocessor that performs calculations, an EEPROM that stores programs and the like for causing the microprocessor to execute each process, a RAM that stores various data such as calculation results, a backup RAM in which the stored contents are retained, and an input / output I / F, etc.

[0039] The HEV-CU 70, ECU 71, PCU 72, TCU 74, and VDCU 76 are connected to each other via a CAN (Controller Area Network) 100 (corresponding to a communication line in the claims) so as to be able to communicate with each other.

[0040] Various sensors are connected to the HEV-CU 70, including, for example, an accelerator pedal sensor 81 that detects the amount of depression of the accelerator pedal, i.e., the accelerator pedal operation amount, and a resolver 82 that detects the rotational position (rotational speed) of the electric motor 40. The HEV-CU 70 also receives various information such as the engine speed, primary pulley speed, secondary pulley speed, brake operation amount, steering wheel angle, and yaw rate from the ECU 71, PCU 72, TCU 74, VDCU 76, etc. via the CAN 100.

[0041] The HEV-CU 70 comprehensively controls the driving of the engine 10, the electric motor 40, and the continuously variable transmission 50 based on the acquired various information. The HEV-CU 70 calculates the required output of the engine 10, the torque command value of the electric motor 40, and the target gear ratio of the continuously variable transmission 50 based on various information such as the accelerator pedal operation amount (driver's required driving force), the engine rotation speed, the motor rotation speed, the primary pulley rotation speed, the secondary pulley rotation speed, the vehicle operating state (vehicle speed, steering angle, etc.), and the state of charge (SOC) of the high-voltage battery 73. The HEV-CU 70 then outputs the calculated required output, torque command value, target gear ratio, etc. via the CAN 100. The HEV-CU 70 also acquires the actual motor torque of the electric motor 40 and transmits it to the TCU 74 via the CAN 100.

[0042] The ECU 71 identifies the cylinder from the output of the cam angle sensor described above, and determines the engine rotation speed (rotational speed) from changes in the rotational position of the crankshaft 15 detected by the output of the crank angle sensor 84. The ECU 71 also acquires various information, such as the intake air amount, accelerator pedal operation amount, air-fuel ratio of the air-fuel mixture, and water temperature, based on detection signals input from the various sensors described above. The ECU 71 then controls the engine 10 by controlling the fuel injection amount, ignition timing, and various devices such as an electronically controlled throttle valve based on the acquired information and the required output from the HEV-CU 70. The ECU 71 stops fuel injection to the engine 10 (performs fuel cut) during coasting control (inertia running control).

[0043] Furthermore, the ECU 71 calculates the actual engine torque (output torque) of the engine 10 based on, for example, the intake air amount and engine speed detected by the air flow meter 83. Then, the ECU 71 transmits information such as the engine speed (rotation speed) and actual engine torque to the TCU 74, HEV-CU 70, etc. via the CAN 100.

[0044] The PCU 72 drives the electric motor 40 via the inverter 72a based on the torque command value from the HEV-CU 70. Here, the inverter 72a converts the DC power of the high-voltage battery 73 into three-phase AC power and supplies it to the electric motor 40. Meanwhile, during regeneration, for example, the inverter 72a converts the AC voltage generated by the electric motor 40 into DC voltage to charge the high-voltage battery 73.

[0045] A brake switch 89 that detects whether the brake pedal is depressed and a brake fluid pressure sensor 90 that detects the master cylinder pressure (brake hydraulic pressure) of the brake actuator are connected to the VDCU 76. Also connected to the VDCU 76 are a wheel speed sensor 91 that detects the rotational speed of each wheel of the vehicle (vehicle speed), etc.

[0046] The VDCU 76 drives the brake actuator to brake the vehicle according to the amount of brake pedal operation (amount of depression), and detects vehicle behavior using various sensors (e.g., wheel speed sensor 91, steering angle sensor, acceleration sensor, yaw rate sensor, etc.), and suppresses skidding and ensures vehicle stability when turning by automatically applying pressure to the brakes and controlling the torque of the engine 10, etc. The VDCU 76 also prevents wheel lock that occurs during sudden braking or braking on slippery roads, and by maintaining an appropriate slip ratio for each wheel, ensures directional stability and maneuverability during braking, and is equipped with an anti-lock brake function (ABS function) that obtains optimal braking force, and a traction control function (TCS function) that suppresses drive wheel spin that occurs on slippery roads or due to excessive driving force, ensuring vehicle stability and acceleration when starting or accelerating.

[0047] The VDCU 76 transmits detected braking information (brake operation information) such as brake switch 89 and brake fluid pressure, wheel speed (vehicle speed), and the like to the TCU 74, HEV-CU 70, ECU 71, and the like via the CAN 100.

[0048] The TCU 74 is connected to a primary pulley rotation sensor 85 that detects the rotation speed of the primary pulley 52, a secondary pulley rotation sensor 86 that detects the rotation speed (corresponding to the vehicle speed) of the secondary pulley 53, etc. In addition, the TCU 74 is also connected to a turbine rotation sensor 87, an output clutch rotation sensor 88, etc.

[0049] In addition, the TCU 74 receives information such as actual engine torque from the ECU 71 via the CAN 100, information such as actual motor torque and accelerator pedal operation amount from the HEV-CU 70, and information such as vehicle speed and brake operation information from the VDCU 76.

[0050] The TCU 74 continuously changes the gear ratio of the continuously variable transmission 50 based on the acquired various information (vehicle operating conditions) and the target gear ratio from the HEV-CU 70.

[0051] At that time, the TCU 74 adjusts the hydraulic pressure supplied to the hydraulic chamber 52c of the primary pulley 52 and the hydraulic chamber 53c of the secondary pulley 53 by controlling the operation of a solenoid valve (electromagnetic valve) constituting the control valve 75 described above, thereby changing the gear ratio of the continuously variable transmission 50. The TCU 74 also controls the operation of a forward clutch solenoid constituting the control valve 75 described above, thereby adjusting the amount of oil supplied to and discharged from the forward clutch 32, thereby engaging and disengaging the forward clutch 32. Similarly, the TCU 74 controls the operation of a reverse clutch solenoid constituting the control valve 75, thereby adjusting the amount of oil supplied to and discharged from the reverse brake 33, thereby engaging and disengaging the reverse brake 33.

[0052] The TCU 74 also adjusts the hydraulic pressure (i.e., the engagement force) supplied to the transfer clutch 64 by controlling the operation of the solenoid valve constituting the control valve 75 described above, thereby adjusting the distribution ratio of the driving force transmitted to the rear wheels. Furthermore, the TCU 74 controls the engagement and disengagement of the output clutch 61 by controlling the operation of the solenoid valve constituting the control valve 75 described above.

[0053] In particular, the TCU 74 has a function of estimating the motor torque even when it is unable to acquire (receive) the motor torque from the HEV-CU 70 (corresponding to another control unit described in the claims) by communication via the CAN 100. In the TCU 74, this function is realized by a microprocessor executing a program stored in an EEPROM or the like.

[0054] Example 1 The TCU 74 executes coasting control when predetermined coasting conditions are met (for example, the accelerator is off, the brake is off, fuel is being cut off during deceleration, and the vehicle speed is 20 km / h or more and the lock-up clutch is engaged). Under normal conditions, the TCU 74 calculates a predicted deceleration (previous deceleration) based on the target primary pulley rotation speed of the continuously variable transmission 50, the actual engine torque acquired from the ECU 71 via the CAN 100, the actual motor torque acquired from the HEV-CU 70 via the CAN 100, the vehicle speed acquired from the VDCU 76 via the CAN 100, and the like. If the predicted deceleration becomes greater than a predetermined threshold, the TCU 74 fixes (keeps constant) the gear ratio of the continuously variable transmission 50 to avoid sudden deceleration when an abnormality occurs.

[0055] On the other hand, when the TCU 74 is unable to acquire (receive) the motor torque from the HEV-CU 70 via the CAN 100 during coasting deceleration (YES in step S100 in FIG. 2 ) (NO in step S102 in FIG. 2 ), the TCU 74 first calculates the engine rotation speed ω of the engine 10 from the vehicle speed v acquired (received) from the VDCU 76 via the CAN 100 using the following equations (1) and (2): engine and vehicle acceleration a are calculated (step S104 in FIG. 2). ω engine =(r gear ×r cvt / R tyre ) / v ···(1) a=dv / dt (2) where r gear : Secondary reduction gear ratio r srgear ×Final gear ratio r final , r cvt : Actual gear ratio, R tyre :Tire radius.

[0056] Next, the TCU 74 calculates the actual engine torque T based on the calculated engine rotation speed, vehicle acceleration, and the actual engine torque T acquired (received) from the ECU 71 via the CAN 100. engine , oil pump torque T oilpumpUsing the following equation (4) derived from the equation of motion of the hybrid vehicle (the following equation (3)), the motor torque T motor is calculated (estimated) (step S106 in FIG. 2). ma=F PU -(F roll +F air )=(r gear ×r cvt / R tyre ){T engine +T motor -T oilpump -I(dω engine / dt)}-{μmg+(ρC d Av 2 ) / twenty three) where F PU : Tire driving force, F roll : Rolling resistance, F air :Air resistance.

[0057] T motor =-T engine +T oilpump +I(dω engine / dt)+{(R tyre / r gear ×r cvt ){ma+μmg+(ρC d Av 2 ) / twenty four) where r gear : Secondary reduction gear ratio r srgear ×Final gear ratio r final , R tyre :Tire radius, T oilpump : mechanical oil pump torque, m: vehicle weight, ρ: air density, C d : air resistance coefficient, A: frontal projected cross-sectional area, μ: rolling resistance coefficient, g: gravitational acceleration, I: inertia (inertia between the crankshaft 15 and the primary pulley 52). These values ​​(specification values ​​other than the variables) are stored as data in, for example, an EEPROM or the like.

[0058] Next, the TCU 74 calculates the target primary pulley rotation speed ω target_rev_primarypulley , actual engine torque T engine , motor torque T motorThe predicted deceleration is calculated from the vehicle speed v and the like (step S108 in FIG. 2). a asumption =f(ω target_rev_primarypulley ,T engine ,T motor ,v,·) ···(5)

[0059] If the predicted deceleration is greater than a predetermined threshold value (YES in step S110 in FIG. 2), the TCU 74 fixes the gear ratio of the continuously variable transmission 50 (step S112 in FIG. 2). If the predicted deceleration is equal to or less than the predetermined threshold value (NO in step S110 in FIG. 2), normal gear change control is executed.

[0060] Example 2 In the first embodiment, when the actual motor torque cannot be obtained from the HEV-CU 70, the motor torque is calculated using the vehicle speed obtained from the VDCU 76. However, instead of the vehicle speed obtained (received) from the VDCU 76 via the CAN 100, the TCU 74 may calculate the turbine rotation speed ω turbine and the gear ratio of the continuously variable transmission 50, and the vehicle speed may be calculated to calculate (estimate) the motor torque using the calculated vehicle speed.

[0061] In this case, the TCU 74 calculates the vehicle speed using the following equation (6). v={R tyre / (r gear ×r cvt )}×ω turbine ···(6) The other configurations (subsequent processes) are the same as or similar to those in the first embodiment, and therefore detailed description thereof will be omitted here.

[0062] Example 3 In the first embodiment, when the actual motor torque cannot be obtained from the HEV-CU 70, the motor torque is calculated using the vehicle speed obtained from the VDCU 76. However, instead of the vehicle speed obtained (received) from the VDCU 76 via the CAN 100, the TCU 74 may calculate the primary pulley rotation speed ω pripulleyand the gear ratio of the continuously variable transmission 50, and the vehicle speed may be calculated to calculate (estimate) the motor torque using the calculated vehicle speed.

[0063] In this case, the TCU 74 calculates the vehicle speed using the following equation (7). v={R tyre / (r gear ×r cvt )}×ω pripulley ···(7) The other configurations (subsequent processes) are the same as or similar to those in the first embodiment, and therefore detailed description thereof will be omitted here.

[0064] Example 4 In the first embodiment, when the actual motor torque cannot be obtained from the HEV-CU 70, the motor torque is calculated using the vehicle speed obtained from the VDCU 76. However, instead of the vehicle speed obtained (received) from the VDCU 76 via the CAN 100, the TCU 74 may calculate the secondary pulley rotation speed ω secpulley The vehicle speed may be calculated from the vehicle speed, and the motor torque may be calculated (estimated) using the calculated vehicle speed.

[0065] In this case, the TCU 74 calculates the vehicle speed using the following equation (8). v={R tyre / (r gear ×r cvt )}×(r cvt ×ω secpulley ) ···(8) The other configurations (subsequent processes) are the same as or similar to those in the first embodiment, and therefore detailed description thereof will be omitted here.

[0066] Example 5 In the first embodiment, when the actual motor torque cannot be obtained from the HEV-CU 70, the motor torque is calculated using the vehicle speed obtained from the VDCU 76. However, instead of the vehicle speed obtained (received) from the VDCU 76 via the CAN 100, the TCU 74 calculates the clutch rotation speed (output shaft rotation speed) ω outclutch The vehicle speed may be calculated from the vehicle speed, and the motor torque may be calculated (estimated) using the calculated vehicle speed.

[0067] In this case, the TCU 74 calculates the vehicle speed using the following equation (9). v={R tyre / (r srgear ×r final ×r cvt )}×(r srgear ×r cvt ×ω outclutch ) ···(9) The other configurations (subsequent processes) are the same as or similar to those in the first embodiment, and therefore detailed description thereof will be omitted here.

[0068] As described above in detail, according to this embodiment (Example 1), when motor torque cannot be obtained from HEV-CU 70 via CAN 100, the engine rotation speed and vehicle acceleration of engine 10 are obtained from the vehicle speed obtained from VDCU 76 via CAN 100, and motor torque is obtained from the equation of motion of the hybrid vehicle using the engine rotation speed, vehicle acceleration, and engine torque obtained from ECU 71 via CAN 100. As a result, even when motor torque cannot be obtained from HEV-CU 70 (another control unit) via CAN 100, it is possible to obtain motor torque.

[0069] Similarly, according to the second to fifth embodiments, even when the motor torque cannot be obtained from the HEV-CU 70 via the CAN 100, the motor torque can be obtained.

[0070] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible. For example, in the above embodiments, the electric motor 40 is connected to the primary shaft 51 of the continuously variable transmission 50, but the connection position of the electric motor 40 may be downstream of the secondary pulley 53 of the continuously variable transmission 50. In this case, the handling of the speed ratio and gear ratio in the above calculation formula is changed according to the arrangement of the continuously variable transmission 50 and the electric motor 40. Furthermore, in the above embodiments, the forward / reverse switching mechanism 30 is arranged in front of the primary pulley 52, but it may also be arranged in rear of the secondary pulley 53.

[0071] In the first to fourth embodiments, if the configuration (specification) does not generate electricity while the vehicle is stopped, the output clutch 61 may be omitted. Also, in the second to fifth embodiments, the VDCU 76 may not be provided.

[0072] In the above embodiment, the CAN 100 is used as the communication line, but the communication line is not limited to the CAN. Also, in the above embodiment, hydraulic types are used as the forward clutch 32, the reverse brake 33, the transfer clutch 64, and the output clutch 61, but electromagnetic types, for example, can also be used.

[0073] In the above embodiment, the engine rotation speed, primary pulley rotation speed, and secondary pulley rotation speed are used in the calculation, but the rotation speed (rpm) may be used instead of the rotation speed (m / s). That is, the engine rotation speed, primary pulley rotation speed, and secondary pulley rotation speed may be used.

[0074] In the above embodiment, the present invention is applied to a chain-type continuously variable transmission 50, but instead of the chain-type continuously variable transmission 50, it can also be applied to, for example, a belt-type continuously variable transmission or a toroidal-type continuously variable transmission.

[0075] In the above embodiment, the determination as to whether or not to perform coasting control is made by the TCU 74, but the determination as to whether or not to perform coasting control may be made by the HEV-CU 70 or the ECU 71, and the determination result may be transmitted to the TCU 74 via the CAN 100. Also, in the above embodiment, the ECU 71 that controls the engine 10 and the TCU 74 that controls the continuously variable transmission 50 are configured as separate pieces of hardware, but they may also be configured as integrated hardware. [Explanation of symbols]

[0076] 1. Continuously variable transmission control device 10 Engine 15 crankshaft 20 Torque converter 21 Pump impeller 22 Turbine runner 23 Stator 24 Lock-up clutch 25 Turbine shaft 30 Forward / reverse switching mechanism 31 Planetary gear train 32 forward clutch 33 Reverse brake 35 Oil pump 40 Electric motor 50 Continuously variable transmission 51 Primary axis 52 Primary pulley 53 Secondary pulley 54 Chain 55 Secondary Axis 59 Reduction gear (secondary reduction gear) 60 Counter shaft 61 Output clutch 62 Parking gear 63 Counter gear 64 Transfer clutch 65 Transfer gear 66 front drive shaft 67 Front differential 68 Propeller shaft 69 Rear differential 70 HEV-CU 71 ECU 72 PCU 73 High Voltage Battery 74 TCU 75 Control valve (valve body) 76 VDCU 81 Accelerator pedal sensor 82 resolver 83 Air flow meter 84 Crank angle sensor 85 Primary pulley rotation sensor 86 Secondary pulley rotation sensor 87 Turbine rotation sensor 88 Output clutch rotation sensor 89 Brake switch 90 Brake fluid pressure sensor 91 Wheel speed sensor 100 CAN

Claims

1. A control device for a continuously variable transmission mounted on a hybrid vehicle including an engine and an electric motor capable of transmitting power between the engine and a crankshaft of the engine, the control device continuously converting at least the engine torque of the engine, a transmission control unit that is communicably connected to an engine control unit that controls the engine, a motor control unit that controls the electric motor, and a vehicle control unit that controls vehicle behavior of the hybrid vehicle via a communication line, and that controls the continuously variable transmission; When a predetermined coasting condition is met and coasting control is being performed, the transmission control unit acquires motor torque from the motor control unit via the communication line, calculates a predicted deceleration based on the motor torque, and fixes the gear ratio of the continuously variable transmission when the predicted deceleration becomes larger than a predetermined threshold value; and when the transmission control unit cannot acquire motor torque from the motor control unit via the communication line, the transmission control unit determines an engine rotation speed and a vehicle acceleration of the engine from the vehicle speed acquired from the vehicle control unit via the communication line, and determines motor torque from an equation of motion of the hybrid vehicle using the engine rotation speed, the vehicle acceleration, and the engine torque acquired from the engine control unit via the communication line.

2. 2. The control device for a continuously variable transmission according to claim 1, wherein the transmission control unit determines the vehicle speed from a turbine rotation speed of a torque converter interposed between the engine and the continuously variable transmission and a gear ratio of the continuously variable transmission, instead of the vehicle speed acquired from the vehicle control unit via the communication line, and determines the motor torque using the vehicle speed.

3. 2. The control device for a continuously variable transmission according to claim 1, wherein the transmission control unit determines the vehicle speed from the primary pulley rotation speed of the continuously variable transmission and the gear ratio of the continuously variable transmission, instead of the vehicle speed acquired from the vehicle control unit via the communication line, and determines the motor torque using the vehicle speed.

4. 2. The control device for a continuously variable transmission according to claim 1, wherein the transmission control unit determines the vehicle speed from a secondary pulley rotation speed of the continuously variable transmission, instead of the vehicle speed acquired from the vehicle control unit via the communication line, and determines the motor torque using the vehicle speed.

5. 2. The control device for a continuously variable transmission according to claim 1, wherein the transmission control unit obtains the vehicle speed from a clutch rotation speed of an output clutch that is provided between the electric motor and the drive wheels and that interrupts torque transmission between the engine and the electric motor and the drive wheels, instead of the vehicle speed obtained from the vehicle control unit via the communication line, and obtains the motor torque using the vehicle speed.

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