Transmission input torque control device

Abstract

The invention provides a transmission input torque control device. When a predetermined learning condition is satisfied, the HEV-CU (70) causes the electric engine (40) to perform a regeneration operation, detects the output torque of the torque converter (20) from the regenerated power generation amount of the electric engine (40), and learns the value of "capacity coefficient * torque ratio" of the torque converter (20) on the basis of the output torque and the number of revolutions of the engine at the time of detection. After learning, the HEV-CU (70) estimates the torque input to the automatic transmission (50) on the basis of the learning value of "capacity coefficient * torque ratio" and the real-time engine speed, and controls the engine (10) such that the estimated input torque does not exceed the upper limit value of the input allowable torque of the automatic transmission (50).

Description

Technical Field

[0001] The present invention relates to a transmission input torque control device for controlling torque input to a transmission. Background Art

[0002] Patent Document 1 discloses an engine torque control device that controls the engine torque so as to reduce the engine torque when the input torque to the transmission is too large in order to protect the transmission. In the engine torque control device, if the engine output torque input to the transmission exceeds the permissible upper limit torque of the transmission, the engine generated torque control value is set so that the transmission input torque becomes less than the permissible upper limit torque.

[0003] However, such an allowable upper limit torque value for limiting the input torque of the transmission is usually set in a manner that maintains a margin. That is, the margin is set in a manner that does not exceed the limit of the transmission even for the upper limit product (worst case) by taking into account the magnitude of individual deviations of the engine, torque converter, etc. and / or the estimation accuracy of the engine torque.

[0004] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2006-170116 Summary of the invention

[0005] Technical issues However, conventionally, the detection accuracy of the torque output from the engine and / or torque converter (i.e., the torque input to the transmission) is low, and the margin has to be increased. On the other hand, the degree of individual deviations and the like differs for each engine and / or torque converter, so if the margin is increased, the output torque of the engine and the like is unnecessarily (excessively) restricted (i.e., the permissible upper limit torque of the transmission is unnecessarily reduced).

[0006] In particular, in mid-range and / or lower-limit products of engines and / or torque converters, the output torque is limited even though there is a margin before the limit of the transmission (hardware), i.e., a situation occurs in which the performance cannot be fully utilized despite the existence of surplus power, and the power performance is suppressed to a low level.

[0007] Therefore, there is a desire to detect the torque input to the transmission (i.e., the torque output from the engine, torque converter) with higher accuracy and to increase the torque as much as possible without exceeding the hardware limits of the transmission (i.e., to make the margin when setting the allowable upper limit torque as small as possible).

[0008] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a transmission input torque control device that can calculate the torque output from the engine and torque converter with higher accuracy, and can increase the torque output from the engine and torque converter and input to the transmission as much as possible without exceeding the limit of the transmission (hardware) (that is, reduce the margin and increase the input allowable torque upper limit as much as possible).

[0009] Technical Solution A transmission input torque control device according to one embodiment of the present invention is characterized in that it comprises: an engine that outputs engine torque; a torque converter that is connected to an output shaft of the engine, transmits the engine torque via oil, and has a torque amplification function; an electric motor that is connected to the output shaft of the torque converter and operates as a motor that outputs motor torque during driving, and on the other hand, operates as a generator during regeneration; an automatic transmission that is connected to the output shaft of the electric motor and converts input torque and outputs it; and a control unit that controls the engine, the torque converter, the electric motor, and the automatic transmission, the control unit causing the electric motor to perform regenerative operation when a predetermined learning condition is satisfied, detecting the output torque of the torque converter based on the regenerative power generation of the electric motor, learning a value of "capacity coefficient × torque ratio" of the torque converter based on the output torque and the engine speed at the time of detection, and after learning, estimating the input torque of the automatic transmission based on the learned value of "capacity coefficient × torque ratio" and the real-time engine speed, and controlling the engine in such a way that the estimated input torque does not exceed the upper limit value of the input allowable torque of the automatic transmission.

[0010] Technical Effects According to the present invention, the torque output from the engine and the torque converter can be calculated with higher accuracy, and the torque output from the engine and the torque converter and input to the transmission can be increased as much as possible without exceeding the limit of the transmission (hardware) (i.e., the margin is reduced and the upper limit of the input allowable torque is increased as much as possible). BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a block diagram showing the configuration of main parts of a transmission input torque control device according to an embodiment and a hybrid vehicle to which the transmission input torque control device is applied.

[0012] Figure 2 This is a diagram showing an example of a performance curve of a torque converter.

[0013] Figure 3 This is a diagram for explaining a method of obtaining learning data of “capacity coefficient×torque ratio” with respect to the speed ratio.

[0014] Figure 4 This is a diagram for explaining a method of estimating output torque using learning data.

[0015] Figure 5 It is a flowchart showing a processing procedure of transmission input torque control by the transmission input torque control device according to the embodiment.

[0016] Explanation of symbols 1 Transmission input torque control device 10 Engine 15 Crankshaft 20 Torque converter 21 Pump impeller 22 Turbine wheel 23 Stator 24 Lock-up clutch 25 Turbine shaft 27 A pair of gears (gear pair) 30 Output clutch 40 Electric Motor 45 Reduction gear 50 Automatic transmission 55 Reverse gear 60 Transfer clutch 66 Front drive shaft 67 Front differential 68 Drive shaft 69 Rear differential 70 HEV-CU 71 ECU 72 PCU 72a Converter 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 87 Turbine rotation sensor 89 Brake switch 90 Brake hydraulic pressure sensor 91 Wheel speed sensor 100 CAN DETAILED DESCRIPTION

[0017] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same symbols are used for the same or corresponding parts. In addition, in each figure, the same elements are marked with the same symbols and repeated descriptions are omitted.

[0018] First, use Figure 1 The configuration of main parts of the transmission input torque control device 1 according to the embodiment and a hybrid vehicle to which the transmission input torque control device 1 is applied will be described. Figure 1 1 is a block diagram showing the configuration of main parts of the transmission input torque control device 1 and a hybrid vehicle to which the transmission input torque control device 1 is applied.

[0019] The engine 10 may be any type of engine, such as a horizontally opposed in-cylinder injection type four-cylinder gasoline engine. In the engine 10, the air sucked in from the air filter (not shown) is throttled via an electronically controlled throttle valve provided in the intake pipe, and is sucked into each cylinder formed in the engine 10 through the intake manifold. Here, the amount of air sucked in from the air filter is detected by an air flow meter 83. Furthermore, a throttle opening sensor for detecting the opening of the throttle is provided on the throttle. An injector for injecting fuel is installed in each cylinder. In addition, a spark plug for igniting the mixed gas and an igniter built-in coil for applying a high voltage to the spark plug are installed in each cylinder.

[0020] In each cylinder of the engine 10, a mixture of air taken in and fuel injected from an injector is ignited by an ignition plug and combusted, and exhaust gas after the combustion is exhausted through an exhaust pipe.

[0021] In addition to the above-mentioned air flow meter 83 and throttle opening sensor, a cam angle sensor for performing cylinder discrimination of the engine 10 is installed near the camshaft of the engine 10. In addition, a crank angle sensor 84 for detecting the rotational position (rotational speed) of the crankshaft 15 is installed near the crankshaft 15 of the engine 10. These sensors are connected to an engine control unit (hereinafter referred to as "ECU") 71 described later. In addition, various sensors such as a water temperature sensor for detecting the temperature of the cooling water of the engine 10 are also connected to the ECU 71.

[0022] The driving force (engine torque) obtained by the combustion of the mixed gas is output from the crankshaft 15. The crankshaft 15 of the engine 10 is connected to an automatic transmission 50 that converts and outputs the engine torque from the engine 10 and / or the motor torque from the electric generator 40 via a torque converter 20 having a clutch function and a torque amplification function, an electric generator 40, and the like.

[0023] 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 causes oil to flow, and the turbine runner 22 arranged opposite to the pump impeller 21 receives the power of the engine 10 through the oil, thereby driving the turbine shaft 25. The stator 23 located between the two generates a torque amplification effect by rectifying the discharge flow (return) from the turbine runner 22 and returning it to the pump impeller 21.

[0024] In addition, the torque converter 20 has a lockup clutch 24 that directly connects the input and the output. The torque converter 20 amplifies the driving force of the engine 10 and outputs it when the lockup clutch 24 is not engaged (in a non-locked state), and directly outputs the driving force of the engine 10 when the lockup clutch 24 is engaged (in a locked state). The number of revolutions (turbine revolutions: output shaft revolutions) of the turbine runner 22 constituting the torque converter 20 is detected by a turbine rotation sensor 87. The detected turbine revolutions are output to a transmission control unit (hereinafter referred to as "TCU") 74 described later.

[0025] Here, in Figure 2 An example of a performance curve (torque characteristic) of the torque converter 20 is shown in FIG. Figure 2 The horizontal axis is the speed ratio, and the vertical axis is the torque ratio, efficiency, and capacity factor (torque capacity factor). The speed ratio, torque ratio, efficiency, and capacity factor are calculated using the following formulas.

[0026] Speed ​​ratio = output shaft speed / input shaft speed (1) Torque ratio = output shaft torque / input shaft torque (2) Efficiency = torque ratio × speed ratio (3) Capacity factor = input shaft torque / input shaft speed 2 (4) Furthermore, the above equation (4) is transformed to obtain the following equation (5).

[0027] Input shaft torque = capacity factor × input shaft speed 2 (5) Similarly, the above equation (2) is transformed to obtain the following equation (6).

[0028] Output shaft torque = torque ratio × input shaft torque (6) Then, by substituting the above equation (5) into the above equation (6), the following equation (7) is obtained.

[0029] Output shaft torque = (capacity factor × torque ratio) × input shaft speed2 (7) Furthermore, the above equation (7) is transformed to obtain the following equation (8).

[0030] (Capacity factor × torque ratio) = output shaft torque / input shaft speed 2 (8) Here, since the input shaft speed = engine speed, the output shaft torque can be detected based on the regenerative power generation (voltage × current) of the electric generator 40 to obtain the individual (each individual) value of (capacity factor × torque ratio) (equivalent to the transfer characteristic described in the claims) (details will be described later).

[0031] The turbine shaft 25 of the torque converter 20 is connected to the motor generator 40 via a pair of gears (a drive gear and a driven gear) 27 and an output clutch 30 .

[0032] Here, the output clutch 30 is interposed between the torque converter 20 and the electric generator 40, and interrupts the torque transmission between the engine 10 and the torque converter 20 and the electric generator 40 (to the drive wheels). For example, during inertial travel control (inertial travel control), during EV travel based on the electric generator 40, and during regenerative braking based on the electric generator 40, the output clutch 30 is released to disconnect the engine 10 and / or the torque converter 20 from the wheel side.

[0033] Among them, for example, even during inertial running control, the output clutch 30 is engaged during learning described later. That is, during learning, the output clutch 30 is engaged, so that the electric generator 40 regenerates power through the torque output from the engine 10 and the torque converter 20, and the torque is obtained from the power generation (details will be described later). It should be noted that the operation (engagement, release) of the output clutch 30 is controlled by the TCU 74 described later.

[0034] The electric generator 40 is configured as a synchronous generator motor (a three-phase AC type synchronous motor) having both the function of a motor that converts supplied electric power into mechanical power and the function of a generator that converts input mechanical power into electric power. That is, the electric generator 40 operates as a motor that generates driving torque when the vehicle is driven, and operates as a generator when regenerating. The electric generator 40 is controlled by a hybrid vehicle control unit (hereinafter referred to as "HEV-CU") 70 described later.

[0035] The electric generator 40 is connected to the high voltage battery 73 via the inverter 72a. When the electric generator 40 functions as a motor, the inverter 72a converts the DC power supplied from the high voltage battery 73 into AC power and drives the electric generator 40. In addition, when the electric generator 40 functions as a generator (Engine), the inverter 72a converts the AC power generated by the electric generator 40 into DC power to charge the high voltage battery 73. Here, as described above, the engine 10, the torque converter 20 and the electric generator 40 are connected in series, and are configured so that the torque output from the torque converter 20 can be absorbed by the electric generator 40 by regeneration.

[0036] The output shaft of the motor generator 40 is connected to the input shaft of the automatic transmission 50 via a reduction gear 45 composed of a pair of gears (reduction drive gear, reduction driven gear). The torque (driving force) output from the engine 10 and / or the motor generator 40 is transmitted (input) to the automatic transmission 50 via the reduction gear 45.

[0037] The automatic transmission 50 converts the input torque and outputs it. In this embodiment, a stepped automatic transmission (step AT) is used as the automatic transmission 50 .

[0038] The automatic transmission 50 is configured to have a speed change mechanism including a speed change gear train. In more detail, the speed change mechanism is configured to have, for example, a plurality of planetary gear sets and friction engagement elements such as clutches and / or brakes, wherein the plurality of planetary gear sets are configured to have a plurality of planetary gears composed of sun gears, ring gears, pinion gears, etc., and the friction engagement elements such as clutches and / or brakes are used to switch (i.e., shift) the power transmission paths of the plurality of planetary gear sets. Therefore, the speed change of the automatic transmission 50 is performed by engaging or releasing the friction engagement elements such as clutches (hereinafter, simply referred to as "clutches, etc." or "clutches"). It should be noted that the automatic transmission 50 is put into a neutral (neutral) state by releasing all clutches. Therefore, for example, during the learning described later, the torque input from the wheel side can be cut off (i.e., not input to the electric motor 40) by automatically putting the automatic transmission 50 into a neutral (neutral) state.

[0039] It should be noted that, as the automatic transmission 50, a parallel two-shaft type stepped automatic transmission may be used instead of a planetary gear type automatic transmission, for example, which selectively switches the combination of gear trains respectively arranged on a pair of shafts arranged in parallel by engaging / releasing a plurality of wet clutches, thereby obtaining a limited number of shift stages. In addition, instead of a step AT, a chain type or belt type continuously variable transmission (CVT), a DCT (Dual Clutch Transmission) having independent clutches in each of the odd-numbered and even-numbered gear sets for shifting and switching them in sequence, etc. may also be used. It should be noted that in the continuously variable transmission, for example, a double pinion type planetary gear train, a forward clutch, a reverse brake, etc. are included, and a neutral (neutral) state is achieved by releasing the forward clutch and the reverse brake constituting the forward and reverse switching mechanism for switching between forward and reverse rotation of the drive wheels (forward and reverse of the vehicle).

[0040] The output shaft of the automatic transmission 50 is connected to the front drive shaft 66 via a counter gear 55 composed of a pair of gears (counter drive gear, counter driven gear). The driving force (torque) output from the output shaft of the automatic transmission 50 is transmitted to the front differential (hereinafter referred to as "front differential") 67 via the counter gear 55 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 is transmitted to the right front wheel via the right front wheel drive shaft.

[0041] On the other hand, a transfer clutch 60 is interposed in the rear section of the counter gear 55 (secondary drive gear) on the output shaft to adjust the driving force (torque) transmitted to the rear differential (hereinafter referred to as "rear differential") 69. The transfer clutch 60 controls the engagement force (i.e., the torque distribution rate to the rear wheels) according to the driving state of the four wheels (e.g., the slip state of the front wheels, etc.) and / or the engine torque, etc. Therefore, the driving force output from the output shaft of the automatic transmission 50 is distributed according to the engagement force of the transfer clutch 60 and is also transmitted to the rear wheel side.

[0042] More specifically, the transfer clutch 60 is connected to a propeller shaft 68 extending toward the rear of the vehicle. Therefore, the driving force (torque) regulated (distributed) by the transfer clutch 60 is transmitted to the rear differential 69 via the propeller shaft 68.

[0043] A left rear wheel drive shaft and a right rear wheel drive shaft are connected to the rear differential 69. The driving force from the rear differential 69 is transmitted to the left rear wheel via the left rear wheel drive shaft, and is transmitted to the right rear wheel via the right rear wheel drive shaft.

[0044] Since the hybrid vehicle is configured as described above, the wheels (vehicle) can be driven by two motive forces, namely, the engine 10 and the motor generator 40. In addition, the motor generator 40 can also be used to perform EV running and / or regeneration (electricity generation).

[0045] More specifically, by configuring the driving force transmission system as described above, the torque of the engine 10 and / or the torque of the electric generator 40 is input to the input shaft of the automatic transmission 50. Then, the torque converted by the automatic transmission 50 is output from the output shaft of the automatic transmission 50 and transmitted to the front drive shaft 66 via the counter gear 55. Then, the torque is distributed to the left and right through the front differential 67 and transmitted to the left and right front wheels.

[0046] On the other hand, part of the torque output from the automatic transmission 50 is transmitted to the propeller shaft 68 via the transfer clutch 60. Here, if a predetermined clutch torque is applied to the transfer clutch 60, the torque distributed according to the clutch torque is output to the propeller shaft 68. Furthermore, the torque is also transmitted to the rear wheels via the rear differential 69.

[0047] The engine 10, electric generator 40 and automatic transmission 50, which are the driving power sources of the vehicle, are comprehensively controlled by a control system consisting of HEV-CU70 (equivalent to the control unit recorded in the claims), ECU71, power control unit (hereinafter referred to as "PCU") 72, TCU74, vehicle dynamic control unit (hereinafter referred to as "VDCU") 76, etc.

[0048] HEV-CU70, ECU71, PCU72, TCU74, and VDCU76 are each configured to include a microprocessor for performing calculations, an EEPROM storing programs for causing the microprocessor to execute various processes, a RAM storing various data such as calculation results, and an input / output I / F.

[0049] The HEV-CU 70 , the ECU 71 , the PCU 72 , the TCU 74 , and the VDCU 76 are connected to each other via a CAN (Controller Area Network) 100 so as to be able to communicate with each other.

[0050] Various sensors including an accelerator pedal sensor 81 for detecting the amount of accelerator pedal depression, i.e., the opening of the accelerator pedal, and a rotary transformer 82 for detecting the rotation position (rotation speed) of the electric motor 40 are connected to the HEV-CU 70. In addition, the HEV-CU 70 receives various information such as engine speed, turbine speed (output shaft speed), regenerative power, brake operation amount, steering angle of the steering wheel, yaw rate, etc. via the CAN 100 and from the ECU 71 and / or the PCU 72, the TCU 74, the VDCU 76, etc.

[0051] Based on the various information obtained, HEV-CU70 comprehensively controls the driving of the engine 10, the electric generator 40 and the automatic transmission 50. HEV-CU70 obtains the requested torque of the engine 10, the torque command value of the electric generator 40 and the target speed ratio of the automatic transmission 50 based on various information such as the accelerator pedal opening (driver's requested torque), engine speed, motor speed, vehicle operation status (vehicle speed and / or steering angle, etc.), regenerative braking amount, and the state of charge (SOC) of the high-voltage battery 73. In addition, HEV-CU70 outputs the obtained requested torque, torque command value, target speed ratio, etc. via CAN100. In addition, HEV-CU70 obtains the actual motor torque of the electric generator 40 and sends it to TCU74 via CAN100.

[0052] In ECU71, the cylinder is identified based on the output of the above-mentioned cam angle sensor, and the engine speed (rotation speed) is obtained based on the change in the rotation position of the crankshaft 15 detected by the output of the crankshaft angle sensor 84. In addition, in ECU71, various information such as the amount of intake air, the accelerator pedal opening, the air-fuel ratio of the mixed gas and the water temperature are obtained based on the detection signals input from the above-mentioned various sensors. And, based on these various information obtained and the requested torque (or requested speed) from HEV-CU70, ECU71 controls the engine 10 by controlling the fuel injection amount and / or ignition timing, and various devices such as the electronically controlled throttle. It should be noted that ECU71 stops the fuel injection relative to the engine 10 (carries out fuel cutoff) during inertial travel control (during inertial travel control). Among them, the fuel injection is not stopped during the learning described later.

[0053] In addition, the ECU 71 calculates the actual engine torque (output torque) of the engine 10 based on the intake air volume and / or the engine speed detected by the air flow meter 83, etc. Then, the ECU 71 sends information such as the engine speed (rotation speed) and the actual engine torque to the TCU 74 and / or the HEV-CU 70 via the CAN 100.

[0054] The PCU 72 drives the electric generator 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 generator 40. On the other hand, during regeneration, the inverter 72a converts the AC voltage generated by the electric generator 40 into a DC voltage to charge the high-voltage battery 73. It should be noted that at this time, the amount of power generated during regeneration (current, voltage) is detected in the PCU 72 and sent to the HEV-CU 70.

[0055] The VDCU 76 is connected to a brake fluid pressure sensor 90 that detects whether the brake switch 89 is depressed and detects the master cylinder pressure (brake oil pressure) of the brake actuator. In addition, the VDCU 76 is also connected to a wheel speed sensor 91 that detects the rotation speed (vehicle speed) of each wheel of the vehicle.

[0056] The VDCU 76 brakes the vehicle by driving the brake actuator according to the amount of operation (depression amount) of the brake pedal, and detects the vehicle behavior through various sensors (such as the wheel speed sensor 91, the steering angle sensor, the acceleration sensor, the yaw rate sensor, etc.), and suppresses the side slip through the brake control based on automatic pressure and the torque control of the engine 10, etc., to ensure the vehicle stability when turning. In addition, the VDCU 76 prevents the wheel lock caused by emergency braking and / or braking on a slippery road surface, and appropriately maintains the slip ratio of each wheel, thereby ensuring the directional stability and steering performance during braking, and can have both a locking brake function (ABS function) for obtaining the optimal braking force, and a traction control function (TCS function) for suppressing the idling of the drive wheels caused by a slippery road surface and / or excessive driving force to ensure the vehicle stability and acceleration performance during starting and / or acceleration.

[0057] The VDCU 76 transmits brake information (brake operation information) such as the detected brake switch 89 and / or brake fluid pressure, wheel speed (vehicle speed), and the like to the TCU 74 , the HEV-CU 70 , the ECU 71 , and the like via the CAN 100 .

[0058] The turbine rotation sensor 87 and the like described above are connected to the TCU 74 . The TCU 74 transmits the detected turbine rotation speed (output shaft rotation speed) and the like to the HEV-CU 70 and the like via the CAN 100 . The TCU 74 receives information such as actual engine torque from the ECU 71 via the CAN 100 , receives information such as actual motor torque and accelerator opening from the HEV-CU 70 , and receives vehicle speed, brake operation information, and the like from the VDCU 76 .

[0059] The TCU 74 changes the speed ratio (gear stage) of the automatic transmission 50 based on the acquired various information (operating state of the vehicle) and the target speed ratio from the HEV-CU 70 .

[0060] At this time, the TCU 74 controls the driving of a solenoid valve constituting the control valve 75 to adjust the hydraulic pressure supplied to the automatic transmission 50 and change the speed ratio (gear stage) of the automatic transmission 50 .

[0061] In addition, the TCU 74 adjusts the hydraulic pressure supplied to the transfer clutch 60 (i.e., adjusts the engagement force) by controlling the drive of the solenoid valve constituting the control valve 75, thereby adjusting the distribution ratio of the driving force transmitted to the rear wheel. Furthermore, the TCU 74 controls the engagement and release of the output clutch 30 by controlling the drive of the solenoid valve constituting the control valve 75. During the learning described later, the TCU 74 puts the automatic transmission 50 into a neutral (neutral) state, engages the output clutch 30, and releases the lockup clutch 24 according to the request (instruction) from the HEV-CU 70.

[0062] Here, the HEV-CU 70 obtains the torque output from the engine 10 and the torque converter 20 with higher accuracy, and has a function of increasing the torque output from the engine 10 and the torque converter 20 and input to the automatic transmission 50 as much as possible within the range that does not exceed the limit of the automatic transmission 50 (hardware) (i.e., a function of reducing the margin and increasing the upper limit value of the input allowable torque as much as possible). In the HEV-CU 70, this function is realized by executing a program stored in an EEPROM or the like by a microprocessor.

[0063] First, when the predetermined learning condition is satisfied (during learning), the HEV-CU70 engages the output clutch 30 sandwiched between the torque converter 20 and the electric generator 40 (requested from the TCU74). In addition, when the predetermined learning condition is satisfied (during learning), the HEV-CU70 sets the automatic transmission 50 to a neutral state (neutral state) (requested from the TCU74). Furthermore, the HEV-CU70 releases the lockup clutch 24 of the torque converter 20 (requested from the TCU74). As a result, the torque from the wheel side can be cut off, and the torque output from the engine 10 and the torque converter 20 can be completely absorbed (regenerated) by the electric generator 40.

[0064] Here, the predetermined learning condition is, for example, whether the automatic transmission 50 can be set to a neutral (neutral) state by the driver's request torque determined based on the operation amount (depression amount) of the accelerator pedal being zero or substantially zero (the accelerator is off). More specifically, for example, the condition may be when the vehicle is parked (when the brake is applied in the P or D range) or when the vehicle is coasting (when the vehicle is driving with the accelerator off and the brake off).

[0065] It should be noted that when regeneration (power generation) is performed while the vehicle is parked, if the engine speed is high, there is a concern that the driver may feel uncomfortable and / or the noise inside and outside the vehicle may become louder (become a problem). On the other hand, during inertial driving, if the vehicle speed is high to a certain extent, problems such as noise are relatively small, so measurement (learning) can be performed at a higher engine speed. In addition, for example, it is also possible to configure the measurement (learning) to be able to be performed during maintenance (setting maintenance mode).

[0066] Next, when the predetermined learning condition is satisfied, the HEV-CU 70 causes the electric generator 40 to perform a regenerative operation, detects the output torque of the torque converter 20 based on the regenerative power generated by the electric generator 40, and obtains the value of the "capacity factor × torque ratio" of the torque converter 20 based on the output torque and the engine speed at the time of detection (using the above formula (8)), and learns the value. Here, since the regenerative power generated by the electric generator 40 can accurately measure the voltage and current, it can be measured with high precision.

[0067] However, since (capacity factor × torque ratio) depends on the speed ratio of the torque converter 20, the HEV-CU 70 obtains learning values ​​in a plurality of arbitrary speed ratios by controlling (variably) the speed of the engine 10, thereby obtaining a plurality of learning values ​​in a range of speed ratios of about 0 to 0.6, for example. That is, the HEV-CU 70 makes the speed ratio of the torque converter 20 variable by changing the engine speed during learning, thereby causing the electric generator 40 to perform regenerative action in a plurality of speed ratios, and detecting the output torque of the torque converter 20 based on the regenerative power generation of the electric generator 40. And, based on the output torque and the engine speed during detection (using the above formula (8)), the value of "capacity factor × torque ratio" relative to the speed ratio of the torque converter 20 is obtained and learned.

[0068] Next, the HEV-CU 70 performs curve fitting on the multiple learning values ​​obtained in the multiple speed ratios by considering the design value of the torque converter 20, thereby obtaining learning data (learning characteristic curve) of "capacity coefficient × torque ratio" relative to the speed ratio. Figure 3 As shown, based on the three learning values ​​(○ marks), curve fitting is used to obtain learning data (learning characteristic curve) of the "capacity coefficient × torque ratio" relative to the individual (each individual) speed ratio. Figure 3 This is a diagram for explaining a method of obtaining learning data (learning characteristic curve) of “capacity coefficient×torque ratio” with respect to the speed ratio. Figure 3 The horizontal axis represents the speed ratio, and the vertical axis represents the capacity factor, torque ratio, and the design value and learning value of "capacity factor × torque ratio".

[0069] Here, by considering the design value of the torque converter 20, it is possible to perform highly accurate curve fitting with fewer learning values. It should be noted that, for example, a known method such as the least square method can be used for curve fitting. In addition, the acquired learning data is stored in a memory such as an EEPROM.

[0070] Thereafter (after learning), the HEV-CU 70 estimates the input torque of the automatic transmission 50 according to the above formula (7) based on the learned value of “capacity factor×torque ratio” corresponding to the real speed ratio (under control) and the real engine speed (under control).

[0071] Here, during learning, it is difficult to measure (learn) until the high load area (high engine speed), so Figure 4 As shown, the output torque at a high load (high rotation) is estimated based on the measured value (learned value) at a low load (low rotation) using the above formula (7). Figure 4 This is a diagram for explaining a method of estimating output torque using learning data. Figure 4 The horizontal axis represents the input rotation speed of torque converter 20 (=engine rotation speed), and the vertical axis represents the output torque of torque converter 20 .

[0072] At this time, the HEV-CU 70 estimates the torque input to the automatic transmission 50 by taking into account the gear ratio of the reduction gear 45 between the motor generator 40 and the automatic transmission 50 and the torque (power running or regeneration) of the motor generator 40 .

[0073] Then, the HEV-CU 70 controls the engine 10 (engine speed) (requests the ECU 71 ) so that the estimated input torque does not exceed the upper limit value of the input allowable torque of the automatic transmission 50 .

[0074] Next, refer to Figure 5 At the same time, the operation of the transmission input torque control device 1 is described. Figure 5 This is a flowchart showing the processing procedure of the transmission input torque control (learning processing, input torque estimation processing, input torque limiting processing) by the transmission input torque control device 1. This processing is repeatedly executed at predetermined timings mainly in the HEV-CU 70.

[0075] First, in step S100, it is determined whether learning has been completed. If learning has been completed, the process proceeds to step S114 described later. On the other hand, if learning has not been completed, the process proceeds to step S102.

[0076] In step S102, it is determined whether the predetermined learning condition is satisfied. Here, if the predetermined learning condition is not satisfied, the process is temporarily exited. On the other hand, if the predetermined learning condition is satisfied, the process moves to step S104. It should be noted that the predetermined learning condition is as described above, so detailed description is omitted here.

[0077] In step S104 , lockup clutch 24 of torque converter 20 is released (requested to TCU 74 ), output clutch 30 is engaged (requested to TCU 74 ), and automatic transmission 50 is set to the neutral state (neutral state) (requested to TCU 74 ).

[0078] Next, in step S106, the electric generator 40 is caused to perform a regenerative action, and the torque output from the torque converter 20 is detected based on the regenerative power generation of the electric generator 40. Based on the output torque and the engine speed during the detection (using the above formula (8)), the value of the "capacity coefficient × torque ratio" of the torque converter 20 is calculated and learned.

[0079] Next, in step S108, it is determined whether a predetermined number (e.g., 3 points) of learning values ​​have been obtained by changing the speed ratio. Here, if the predetermined number of learning values ​​has not been obtained, the above-mentioned steps S106 to S108 are repeatedly executed after the engine speed (i.e., speed ratio) is changed in step S110 until the predetermined number of learning values ​​are obtained. That is, in multiple speed ratios, the torque output from the torque converter 20 is detected based on the regenerative power generation of the electric generator 40, and based on the output torque and the engine speed at the time of detection (using the above formula (8)), the value of "capacity coefficient × torque ratio" relative to the speed ratio of the torque converter 20 is obtained and learned.

[0080] On the other hand, when a predetermined number of learning values ​​are obtained, the process moves to step S112. In step S112, a plurality of learning values ​​obtained at a plurality of speed ratios are curve-fitted in consideration of the design value of the torque converter 20, thereby obtaining learning data (characteristic curve after learning) of "capacity coefficient × torque ratio" relative to the speed ratio, which is stored as a map, for example.

[0081] Next, in step S114, the real-time (control) turbine speed (output shaft speed) and engine speed (input shaft speed) are read, and the real-time speed ratio (output shaft speed / input shaft speed) is calculated based on the turbine speed and engine speed. It should be noted that the output shaft speed can also be calculated based on the motor speed.

[0082] In the next step S116, the real-time speed ratio obtained in step S114 is used to retrieve the learning data stored in step S112, for example, as a map, and obtain a learning value of "capacity coefficient × torque ratio" corresponding to the speed ratio. Based on the learning value and the real-time engine speed, the torque input to the automatic transmission 50 is estimated using the above formula (7).

[0083] Then, in step S118, the engine 10 (engine speed) is controlled so that the estimated input torque obtained in step S116 does not exceed the upper limit value of the input allowable torque of the automatic transmission 50. Then, the present process is temporarily exited thereafter.

[0084] As described above in detail, according to the present embodiment, when the predetermined learning condition is satisfied, the electric generator 40 is regenerated, and the output torque of the torque converter 20 is detected based on the regenerative power generation of the electric generator 40, and the value of the "capacity factor × torque ratio" of the torque converter 20 is learned based on the output torque and the engine speed at the time of detection. And after learning, the torque input to the automatic transmission 50 is estimated based on the learned value of the "capacity factor × torque ratio" and the real-time engine speed, and the engine 10 is controlled so that the estimated input torque does not exceed the upper limit value of the input allowable torque of the automatic transmission 50. Here, since the power generation (current value and voltage value) of the electric generator 40 can be accurately detected, the torque output from the engine 10 and the torque converter 20 can be accurately detected. In addition, since the engine speed can also be accurately detected, the "capacity factor × torque ratio" of the individual (each individual) torque converter 20 can be accurately obtained (learned). Therefore, thereafter, the torque output from the engine 10 and the torque converter 20 can be more accurately obtained based on the learned value and the real-time engine speed.

[0085] As a result, according to the present embodiment, when the vehicle is driven by the engine 10 (including the engine 10 and the electric generator 40), the torque output from the engine 10 and the torque converter 20 can be obtained with higher accuracy, and the torque output from the engine 10 and the torque converter 20 and input to the automatic transmission 50 can be increased as much as possible within the range that does not exceed the limit of the automatic transmission 50 (hardware) (that is, the margin is reduced and the input allowable torque upper limit is increased as much as possible). In addition, as a result, for example, when starting on a slope or when going over a step, the power performance can be improved by using up the torque limit of the automatic transmission 50.

[0086] In particular, according to the present embodiment, during learning, the speed ratio of the torque converter 20 is made variable by making the speed ratio of the engine 10 variable, and the output torque of the torque converter 20 is detected in a plurality of speed ratios based on the regenerative power generation of the electric generator 40, and a plurality of learning values ​​corresponding to the plurality of speed ratios are acquired based on the output torque and the engine speed at the time of detection. In addition, at this time, by performing curve fitting on the plurality of learning values ​​learned in the plurality of speed ratios in consideration of the design value of the torque converter 20, learning data of "capacity coefficient × torque ratio" corresponding to the speed ratio is acquired. And after learning, the input torque of the automatic transmission 50 is estimated based on the learning value of "capacity coefficient × torque ratio" corresponding to the real-time speed ratio and the real-time engine speed, and the engine 10 is controlled so that the estimated input torque does not exceed the upper limit value of the input allowable torque of the automatic transmission 50. In this way, by performing learning (torque measurement) with a change in the speed ratio, the torque in the high rotation range (high torque range) can be estimated with high accuracy. In addition, the detection accuracy of the torque output from the torque converter 20 can be improved thereby, and the margin for setting the input allowable torque upper limit value can be reduced. Therefore, the torque limit of the automatic transmission 50 can be fully utilized.

[0087] According to the present embodiment, the predetermined learning condition is whether the automatic transmission 50 can be set to the neutral state by the driver's request torque determined based on the operation amount of the accelerator pedal being zero or substantially zero. When the predetermined learning condition is satisfied (i.e., during learning), the automatic transmission 50 is automatically set to the neutral state. Therefore, the torque input from the wheel side to the electric generator 40 can be cut off, and only the torque output from the engine 10 and the torque converter 20 can be detected. In addition, the output torque can be measured without giving the driver a sense of discomfort (without changing the driving torque of the wheel).

[0088] In addition, according to the present embodiment, an output clutch 30 is provided between the torque converter 20 and the electric generator 40, and the output clutch 3 is engaged during learning. Therefore, during EV driving, during normal regeneration (except during learning), and during normal inertial driving (except during learning), the output clutch 30 is released to disconnect the engine 10 and the torque converter 20, and drag (friction) is reduced. On the other hand, during learning, the electric generator 40 can be regenerated by the torque output by the engine 10 and the torque converter 20 by engagement, and the torque can be obtained from the power generation thereof.

[0089] Furthermore, according to the present embodiment, the input torque of the automatic transmission 50 is estimated by further considering the gear ratio of the reduction gear 45 interposed between the electric generator 40 and the automatic transmission 50 and the torque (power running or regeneration) of the electric generator 40. Therefore, the torque input to the automatic transmission 50 can be detected with higher accuracy and can be controlled.

[0090] The embodiments of the present invention are described above, but the present invention is not limited to the above embodiments and can be modified in various ways. For example, in the above embodiments, the present invention is described as being applied to an AWD vehicle (all-wheel drive vehicle), but the present invention can also be applied to, for example, a 2WD vehicle. In addition, the form and / or mechanism of the automatic transmission 50 are not limited to the above embodiments. For example, it can also be applied to other forms of transmissions such as a continuously variable transmission (CVT), a DCT (Dual Clutch Transmission) instead of a stepped automatic transmission (step AT).

[0091] In addition, the system configuration of controllers such as HEV-CU70 and / or ECU71, TCU74, and the function sharing of each controller are not limited to the above-mentioned embodiment. For example, in the above-mentioned embodiment, although HEV-CU70, ECU71, TCU74, etc. are connected by CAN100 in a manner that allows them to communicate with each other, the system configuration is not limited to such a form, and can be arbitrarily changed (integrated, etc.) in consideration of functional requirements, cost, etc. In addition, it is also possible to configure without VDCU76.

[0092] In the above-described embodiment, although a hydraulic type is used as the output clutch 30 and the transfer clutch 60 , an electromagnetic type may be used, for example.

Claims

1. A transmission input torque control device, characterized in that: have: an engine that outputs an engine torque; A torque converter connected to the output shaft of the engine, transmitting the engine torque via oil, and having a torque amplification function; an electric generator connected to the output shaft of the torque converter and operating as a motor outputting motor torque during driving and operating as a generator during regeneration; An automatic transmission connected to the output shaft of the electric motor and converting the input torque into an output; as well as a control unit that controls the engine, the torque converter, the electric motor, and the automatic transmission, The control unit causes the electric motor to perform a regenerative operation when a predetermined learning condition is satisfied, detects an output torque of the torque converter based on an amount of regenerative power generated by the electric motor, and learns a value of a transfer characteristic of the torque converter based on the output torque and an engine speed during the detection. After learning, the torque input to the automatic transmission is estimated based on the learned value of the transfer characteristic of the torque converter and the real engine speed, and the engine is controlled so that the estimated input torque does not exceed the upper limit value of the input allowable torque of the automatic transmission.

2. The transmission input torque control device according to claim 1, characterized in that: The transfer characteristic of the torque converter is the "capacity factor×torque ratio" of the torque converter.

3. The transmission input torque control device according to claim 2, characterized in that: The predetermined learning condition is whether the automatic transmission can be placed in a neutral state when the driver's request torque determined based on the amount of operation of the accelerator pedal is zero or substantially zero, The control unit automatically sets the automatic transmission to a neutral state when the predetermined learning condition is satisfied.

4. The transmission input torque control device according to claim 2, characterized in that: The control unit releases the lockup clutch of the torque converter during learning, and makes the speed ratio, which is the ratio of the input rotation speed to the output rotation speed of the torque converter, variable, causes the electric motor to perform regenerative operation in a plurality of speed ratios, detects the output torque of the torque converter based on the regenerative power generation of the electric motor, and learns the value of "capacity coefficient × torque ratio" of the speed ratio of the torque converter relative to the output torque and the engine rotation speed during detection, After learning, the control unit estimates the input torque of the automatic transmission based on the learned value of "capacity coefficient×torque ratio" corresponding to the real speed ratio and the real engine speed, and controls the engine in such a way that the estimated input torque does not exceed an upper limit value of the input allowable torque of the automatic transmission.

5. The transmission input torque control device according to claim 4, characterized in that: The control unit acquires learning data of “capacity coefficient×torque ratio” with respect to the speed ratio by performing curve fitting on the plurality of learning values ​​acquired in the plurality of speed ratios in consideration of the design value of the torque converter.

6. The transmission input torque control device according to claim 5, characterized in that: The transmission input torque control device further includes a clutch interposed between the torque converter and the electric generator. The control unit engages the clutch during learning.

7. The method according to claim 6, characterized in that: The control unit estimates an input torque of the automatic transmission in consideration of a gear ratio between the electric motor and the automatic transmission and a torque of the electric motor.

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