JP2009190442A - Control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable carrying out a torque down of a motor during gear change without being affected by battery restriction or revolution speed of an engine in a control device of a vehicle which is equipped with an engine and motor, and outputs driving force from the motor to driving wheel through the automatic transmission. <P>SOLUTION: When the driving current of the motor (a second motor generator MG 2) cannot be reduced during gear change (when a possibility of battery restriction or excess rotation of engine exists), the torque down is carried out by reducing driving efficiency of the second motor generator MG 2. Carrying out of the torque down during gear change becomes possible without being affected by battery restriction or revolution speed of the engine, since power consumption does not decrease and power balance does not change by performing the torque down thus by degradation of driving efficiency, and deterioration of gear change shock can be prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle control apparatus that includes an engine and an electric motor that output driving force for traveling, and that outputs power from the electric motor to driving wheels via a transmission.

  In recent years, from the viewpoint of environmental protection, it has been desired to reduce exhaust gas emissions from engines (internal combustion engines) mounted on vehicles and to improve fuel consumption rate (fuel consumption). Hybrid vehicles equipped with are put into practical use.

  The hybrid vehicle includes an engine such as a gasoline engine or a diesel engine, and an electric motor (for example, a motor generator or a motor) that is driven by power generation by the engine output or battery power to assist engine output. Either one or both of them is used as a driving source.

  In the hybrid vehicle, the operating range (specifically, driving or stopping) of the engine and the electric motor is controlled based on the vehicle speed and the accelerator opening. For example, in a region where the engine efficiency is low, such as when starting or running at a low speed, the engine is stopped and the drive wheels are driven by the power of only the electric motor. Further, during normal traveling, control is performed such that the engine is driven and the driving wheels are driven by the power of the engine. Further, at the time of high load such as full-open acceleration, in addition to engine power, control is performed such that power is supplied from the battery to the electric motor and the power from the electric motor is added as auxiliary power.

  As one of such hybrid vehicle drive devices, for example, a mechanism using a sun gear, a ring gear, and a carrier (pinion gear) as rotating elements, the output of the engine is supplied to a first electric motor (hereinafter also referred to as a generator) and a transmission shaft (ring gear). A power distribution mechanism that distributes the output to the shaft) (or combines the output of the engine and the output of the first electric motor to output to the transmission shaft), the second electric motor, the second electric motor (hereinafter also referred to as a motor), and the drive wheels. A stepped automatic transmission provided between the first and second motors, and a battery capable of charging generated power from the first and second motors and supplying power to the first and second motors. A vehicle drive device that outputs power from a second motor to drive wheels via an automatic transmission is known (see, for example, Patent Documents 1 and 2).

  In such a vehicle drive device, the power distribution mechanism functions as a differential mechanism, and the main part of the power from the engine is mechanically transmitted to the drive wheels by the differential action, and the remaining part of the power from the engine is transferred. By electrically transmitting using the electric path from the 1st electric motor to the 2nd electric motor, it functions as a transmission in which a gear ratio is changed electrically. As a result, the vehicle can be run while maintaining the engine in an optimum operating state, and fuel consumption can be improved. Further, in this type of hybrid vehicle drive device, the power balance is normally controlled to be zero when the generator power generation amount, the battery charge / discharge amount, and the motor consumption amount are all added.

  On the other hand, a planetary gear type transmission that sets a gear stage (shift stage) using a clutch or brake that is a friction engagement element and a planetary gear unit is applied as a transmission mounted on a hybrid vehicle. For example, there are two brakes as friction engagement elements, a gear position that engages one brake and releases the other brake (for example, a low speed gear), and a gear that engages the other brake and releases one brake. Switching to a stage (for example, a high-speed stage) is performed. In this case, a so-called clutch-to-clutch shift is performed in which the engagement of the frictional engagement element on the engagement side and the release of the frictional engagement element on the release side are simultaneously performed during the shift.

  A vehicle such as a hybrid vehicle is provided with a shift operation device operated by a driver. By operating a shift lever of the shift operation device, the shift position of the automatic transmission is set to, for example, P (parking). The position, R (reverse) position, N (neutral) position, D (drive) position, and the like can be switched. Further, in recent years, a shift operation device with a sequential mode has been put into practical use. In sequential mode, a sequential shift range of multiple stages (for example, 8 stages) is set, and when the shift lever is placed in the S (sequential) position and an upshift (+) or downshift (−) operation is performed, The sequential shift range is increased or decreased. When such a sequential mode is selected, the engine speed is controlled to be higher than when traveling in the D range.

In addition, as a technique related to control of a hybrid vehicle, in Patent Document 3 below, in a hybrid vehicle in which a transmission is provided between an engine, a motor generator, and driving wheels, torque reduction of input torque input to the transmission at the time of shifting is performed. A technique for performing the control is described.
JP 2005-212494 A JP 2006-273071 A JP 2004-129494 A

  By the way, in the above-described hybrid vehicle, when the motor torque is reduced, the power consumption is reduced, and surplus power is generated. In order to absorb the surplus power amount, it is necessary to implement either a method of reducing the amount of power generation or charging the battery.

  However, in order to reduce the amount of power generated, it is necessary to reduce the torque of the generator (first motor) responsible for the engine torque reaction force. However, if the generator torque is reduced, the engine torque reaction force is absorbed. Since it becomes impossible to complete, engine overspeed may be caused. Therefore, the method for reducing the amount of power generation cannot be performed under the condition where the engine is running at a high speed. Further, in the method of absorbing the surplus power amount by charging the battery, the method cannot be implemented when there is a battery charge restriction (temperature restriction, SOC (State of Charge) restriction, or the like).

  For this reason, a shift shock may occur if torque reduction cannot be performed during a shift. That is, when the torque capacity is small during the shift (when the friction engagement element is in the released state), if the accelerator pedal is depressed, it is necessary to reduce the torque of the motor (second electric motor). If the torque reduction cannot be carried out for the reason described above, the blow of the motor (second electric motor) that is the gear to be shifted cannot be restricted, and therefore between the motor rotation speed and the engagement target rotation speed (synchronous rotation speed of the target gear) The friction engagement element is engaged in a state where there is a differential rotation, and an engagement shock may occur.

  The present invention has been made in consideration of such circumstances, and includes a control unit for a vehicle that includes an engine and an electric motor that output driving force for traveling, and outputs power from the electric motor to driving wheels via a transmission. An object of the present invention is to realize a control capable of reducing the torque of an electric motor during a shift without being affected by a battery limit or an engine speed.

  The present invention includes an engine and an electric motor that output a driving force for traveling, a power storage device that can charge electric power generated from the electric motor and supply electric power to the electric motor, and a transmission, and can transmit power from the electric motor. It is premised on a vehicle control device that outputs to drive wheels via the transmission. In such a vehicle control device, the loss of the electric motor is temporarily increased during the shift of the transmission. It is characterized by having a torque down control means for lowering the driving efficiency.

  In the present invention, when the control for reducing the drive current of the motor cannot be performed during the shift of the transmission, the torque reduction is performed only by reducing the drive efficiency of the motor. In addition, when it is possible to perform control for reducing the drive current of the motor (motor) during gear shifting, torque reduction is performed by reducing the drive current of the motor as much as possible within the feasible range (conditions). Control may be performed in which the amount of torque reduction that is insufficient only by torque reduction due to current reduction is compensated by torque reduction due to reduction in drive efficiency of the electric motor.

  According to the present invention, when the drive current of the electric motor (motor) cannot be reduced during gear shifting (when there is a possibility of battery limitation or engine overspeed), the drive efficiency of the electric motor is reduced to reduce the torque. Therefore, even if the torque is reduced, the power consumption does not decrease and the power balance does not change. Thus, torque reduction during gear shifting can be performed without being affected by battery limitation (charging limitation of power storage device) and engine speed, and deterioration of gear shifting shock can be prevented.

  The present invention will be described more specifically.

  First, in the present invention, when the control for reducing the drive current of the electric motor (motor) can be performed during shifting as described above, torque reduction is performed by reducing the drive current as much as possible, and the amount of torque reduction is insufficient. If this is compensated by torque reduction due to a decrease in the drive efficiency of the motor, a decrease in drive efficiency, that is, a motor loss can be reduced, so that deterioration in fuel consumption can be reduced.

  In the present invention, a plurality of methods for reducing the drive efficiency are set, and any one of the plurality of drive efficiency reduction methods may be selected to reduce the drive efficiency of the motor. Specifically, for example, a first drive efficiency reduction method for reducing the drive efficiency of the motor by increasing the carrier frequency of the inverter of the motor and increasing the switching loss, the phase of the drive current of the motor with respect to the rotor magnetic field A third driving efficiency lowering method that lowers the driving efficiency of the electric motor by shifting, or a third driving efficiency lowering of the electric motor by both the first driving efficiency lowering method and the second driving efficiency lowering method. Any one of the drive efficiency reduction methods may be selected to reduce the drive efficiency of the electric motor so as to reduce the torque during the shift.

  In this case, for example, when the amount of torque reduction required during the shift is small and torque reduction can be achieved only by the first drive efficiency reduction method or the second drive efficiency reduction method, the first or second drive efficiency If any one of the reduction methods is selected to reduce the drive efficiency of the motor, and the torque reduction amount is large, the third drive efficiency reduction method is selected to reduce the drive efficiency of the motor. Good.

  Further, when either one of the first and second driving efficiency lowering methods is selected, the current temperatures of the inverter and the electric motor are detected by temperature sensors or the like, respectively, and the inverter or the electric motor is based on the temperature detection result. Among them, a method (first or second driving efficiency lowering method) in which the heat generation amount with a larger margin with respect to the allowable temperature becomes larger may be selected to reduce the driving efficiency of the electric motor. For example, when the inverter has a margin for the allowable temperature, the first driving efficiency reduction method is selected, and when the motor has a margin for the allowable temperature, the second driving efficiency reduction method is selected. Then, the drive efficiency of the second motor generator MG2 may be reduced.

  Similarly, when the third drive efficiency reduction method is selected, the current temperatures of the inverter and the motor are detected, and if the inverter has a margin for the allowable temperature, the heat generation amount of the inverter is set larger. If the motor has a margin with respect to the allowable temperature, the control is performed to set the heat generation amount of the motor large and to set the heat generation amount of the inverter 4 small. Thus, the drive efficiency of the electric motor may be reduced.

  Thus, by controlling the decrease in drive efficiency in consideration of the heat generation amounts of the inverter and the electric motor, it is possible to reduce the torque during the shift while suppressing an increase in the thermal load of the inverter and the electric motor.

  Here, the present invention is particularly suitable for a hybrid vehicle capable of selecting a sequential mode in which a manual shift operation is performed. That is, in a vehicle such as a hybrid vehicle, when the sequential mode is selected, control for maintaining the engine speed higher than that in the case of traveling in the D range is executed, so that a margin for engine overspeed is severe. The engine overspeed is likely to occur due to the increase in the rotational speed during the shift, but by reducing the drive efficiency of the electric motor and reducing the torque as in the present invention, the change in the engine rotational speed during the shift can be suppressed. Even when the sequential mode is selected, the engine speed can be kept below the upper limit speed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an example of a hybrid vehicle to which the present invention is applied.

  The hybrid vehicle HV in this example includes an engine 1, a first motor generator MG 1, a second motor generator MG 2, a power distribution mechanism 2, an automatic transmission 3, an inverter 4, a battery (HV battery) 5, a differential gear 6, and drive wheels 7. , A hydraulic control circuit 300 (see FIG. 4), a shift operation device 8 (see FIG. 5), an ECU (Electronic Control Unit) 100, and the like.

  The engine 1, the motor generators MG1 and MG2, the automatic transmission 3, the power distribution mechanism 2, the automatic transmission 3 (including the hydraulic control circuit 300), the shift operation device 8, and each part of the ECU 100 will be described below.

-Engine-
The engine 1 is a known power device that outputs power by burning fuel such as a gasoline engine or a diesel engine, and can control the operation state such as throttle opening (intake amount), fuel injection amount, and ignition timing. It is configured. The rotation speed (engine rotation speed) of the crankshaft 11 that is the output shaft of the engine 1 is detected by the engine rotation speed sensor 201. The engine 1 is driven and controlled by the ECU 100.

-Motor generator-
Motor generators MG1 and MG2 are AC synchronous motors that function as electric motors as well as electric generators. Motor generators MG 1 and MG 2 are connected to battery 5 through inverter 4. Inverter 4 is controlled by ECU 100, and regeneration or power running (assist) of motor generators MG 1 and MG 2 is set by the control of inverter 4. The regenerative power at that time is charged into the battery 5 via the inverter 4. Driving power for motor generators MG1 and MG2 is supplied from battery 5 via inverter 4.

-Power distribution mechanism-
The power distribution mechanism 2 includes an external gear sun gear S21, an internal gear ring gear R21 arranged concentrically with the sun gear S21, a plurality of pinion gears P21 that mesh with the sun gear S21 and mesh with the ring gear R21, and the plurality of pinion gears P21. And a carrier CA21 that holds the pinion gear P21 in a rotatable and revolving manner, and a planetary gear mechanism that performs a differential action using the sun gear S21, the ring gear R21, and the carrier CA21 as rotational elements.

  The crankshaft 11 of the engine 1 is connected to the carrier CA21 of the power distribution mechanism 2. In addition, the rotation shaft of the first motor generator MG1 is connected to the sun gear S21 of the power distribution mechanism 2. A ring gear shaft 21 is connected to the ring gear R21 of the power distribution mechanism 2. The ring gear shaft 21 is connected to the drive wheel 7 via the differential gear 6. Further, the rotary shaft of the second motor generator MG <b> 2 is connected to the ring gear shaft 21 via the automatic transmission 3.

  In the power distribution mechanism 2 having such a structure, when the first motor generator MG1 functions as a generator, the power from the engine 1 input from the carrier CA21 is applied to the sun gear S21 side and the ring gear R21 side according to the gear ratio. Distribute. On the other hand, when first motor generator MG1 functions as an electric motor, the power from engine 1 input from carrier CA21 and the power from first motor generator MG1 input from sun gear S21 are integrated and output to ring gear R21. .

-Automatic transmission-
As shown in FIG. 2, the automatic transmission 3 is a planetary gear type equipped with a double pinion type first planetary gear mechanism 31, a single pinion type second planetary gear mechanism 32, two brakes B1, B2, and the like. The input shaft 30 is coupled to the rotation shaft of the second motor generator MG2. The output shaft 33 of the automatic transmission 3 is connected to the ring gear shaft 21 (FIG. 1).

  The first planetary gear mechanism 31 includes an external gear sun gear S31, an internal gear ring gear R31 disposed concentrically with the sun gear S31, a plurality of first pinion gears P31a meshing with the sun gear S31, and the first pinion gear. A plurality of second pinion gears P31b that mesh with P31a and mesh with ring gear R31, and a carrier CA31 that holds the plurality of first pinion gears P31a and the plurality of second pinion gears P31b so as to rotate and revolve freely. The carrier CA31 of the first planetary gear mechanism 31 is integrally connected to the carrier CA32 of the second planetary gear mechanism 32. The sun gear S31 of the first planetary gear mechanism 31 is selectively connected to the housing 3A, which is a non-rotating member, via the brake B1, and the rotation of the sun gear S31 is prevented by the engagement of the brake B1.

  The second planetary gear mechanism 32 includes an external gear sun gear S32, an internal gear ring gear R32 arranged concentrically with the sun gear S32, a plurality of pinion gears P32 meshing with the sun gear S32 and meshing with the ring gear R32. And a carrier CA32 that holds the plurality of pinion gears P32 so as to rotate and revolve freely. The sun gear S32 of the second planetary gear mechanism 32 is connected to the input shaft 30, and the carrier CA32 is connected to the output shaft 33. Further, the ring gear R32 of the second planetary gear mechanism 32 is selectively coupled to the housing 3A via the brake B2, and the rotation of the ring gear R32 is prevented by the engagement of the brake B2.

  The rotational speed of the input shaft 30 of the automatic transmission 3 (input shaft rotational speed) is detected by the input shaft rotational speed sensor 203. Further, the rotational speed (output shaft rotational speed) of the output shaft 33 of the automatic transmission 3 is detected by the output shaft rotational speed sensor 204. Based on the rotation speed ratio (output shaft rotation speed / input shaft rotation speed) obtained from the output signals of the input shaft rotation speed sensor 203 and the output shaft rotation speed sensor 204, the current gear stage of the automatic transmission 3 is determined. be able to.

  The automatic transmission 3 is operated by a driver operating a shift lever 81 (see FIG. 5) of the shift operation device 8, for example, P range (parking range), N range (neutral range), D range (forward travel range), and the like. You can switch to

  In the automatic transmission 3 described above, the gear stage (shift stage) is set by engaging or releasing the brakes B1 and B2, which are friction engagement elements, in a predetermined state. The engagement / release state of the brakes B1 and B2 of the automatic transmission 3 is shown in the operation table of FIG. In the operation table of FIG. 3, “◯” represents “engaged”, and “blank” represents “release”.

  In the automatic transmission 3 of this example, the input shaft 30 (the rotation shaft of the second motor generator MG2) and the output shaft 33 (the ring gear shaft 21) can be disconnected by releasing both the brakes B1 and B2. Neutral state).

  The transmission gear stage “Lo” is set by engaging the brake B2 and releasing the brake B1. When the brake B2 is engaged, the rotation of the ring gear R32 of the second planetary gear mechanism 32 is fixed, and the carrier CA32, that is, the output shaft is generated by the ring gear R32 to which the rotation is fixed and the sun gear S32 rotated by the second motor generator MG2. 33 rotates at a low speed.

  The transmission gear stage “Hi” is set by engaging the brake B1 and releasing the brake B2. When the brake B1 is engaged, the rotation of the sun gear S31 of the first planetary gear mechanism 31 is fixed, and the rotation of the sun gear S31 (ring gear 31) rotated by the second motor generator MG2 is fixed by the rotation of the sun gear S31. The carrier CA32 (carrier CA31), that is, the output shaft 33 rotates at a high speed.

  In the automatic transmission 3 described above, the upshift from “Lo” to “Hi” is achieved by clutch-to-clutch shift control in which the brake B2 is released and the brake B1 is engaged at the same time. Further, the down shift from “Hi” to “Lo” is achieved by clutch-to-clutch shift control in which the brake B1 is released and the brake B2 is engaged at the same time. The hydraulic pressure when the brakes B1 and B2 are engaged or released is controlled by a hydraulic pressure control circuit 300 (see FIG. 4).

-Hydraulic control circuit-
The hydraulic control circuit 300 is provided with a linear solenoid valve and a control valve, which will be described later, and controls the excitation and non-excitation of the solenoid valve to switch the hydraulic circuit so that the brakes B1 and B2 of the automatic transmission 3 are engaged. You can control merge and release. Excitation / de-excitation of the linear solenoid valve of the hydraulic control circuit 300 is controlled by a solenoid control signal (instructed hydraulic signal) from the ECU 100.

  FIG. 4 shows a schematic configuration of the hydraulic control circuit 300. As shown in FIG. 4, the hydraulic control circuit 300 is driven by the rotation of the engine 1 and supplies oil (automatic transmission fluid: ATF) with an oil flow with sufficient pumping performance to operate the brakes B1 and B2. A mechanical pump MP that is pumped to the passage 301, a three-way solenoid valve 302 and a pressure control valve 303 that adjust the line hydraulic pressure PL of the oil pumped from the mechanical pump MP to the oil passage 301, and a line hydraulic pressure PL are used. And linear solenoid valves 304 and 305 for adjusting the engagement force of the brakes B1 and B2, control valves 306 and 307, and accumulators 308 and 309.

  In this hydraulic control circuit 300, the line hydraulic pressure PL can be adjusted by driving the 3-way solenoid valve 302 to control the opening and closing of the pressure control valve 303.

  The engaging force of the brakes B1 and B2 is adjusted by controlling the opening and closing of the control valves 306 and 307 that transmit the line hydraulic pressure PL to the brakes B1 and B2 by controlling the current applied to the linear solenoid valves 304 and 305. can do.

  In the hydraulic control circuit 300, excess oil that has not been used for the operation of the brakes B1 and B2 among the oil pumped from the mechanical pump MP, and pressure control after being used for the operation of the brakes B1 and B2. The oil returned from the valve 303 is supplied as lubricating oil to the power distribution mechanism 2 or the like via the oil flow path 310.

-Shift operation device-
On the other hand, a shift operation device 8 as shown in FIG. 5 is arranged in the vicinity of the driver seat of the hybrid vehicle HV. The shift operating device 8 is provided with a shift lever 81 that can be displaced.

  In this example, the shift operation device 8 has a P (parking) position, an R (reverse) position, an N (neutral) position, and a D (drive) position, and the driver moves the shift lever 81 to a desired position. Can be displaced. Each position of these P position, R position, N position, and D position (including the shift up (+) position and shift down position (−) position of the S position described below) is determined by the shift position sensor 206 (see FIG. 6). Detected.

  The P position and the N position are non-traveling positions that are selected when the vehicle is not traveling, and the R position and the D position are traveling positions that are selected when the vehicle is traveling.

  Further, as shown in FIG. 5B, the shift operation device 8 is provided with an S (sequential) position 82, and when the shift lever 81 is operated to the S position 82, a manual shift operation is performed. A sequential mode (manual shift mode) is set.

  In this example, for example, eight sequential shift ranges S1 to S8 are set, and when the shift lever 81 is operated to upshift (+) or downshift (−), the sequential shift range is up or down. . For example, the sequential shift range is increased by one step for each operation to the upshift (+) (for example, S1 → S2 →... → S8). On the other hand, the sequential shift range is decreased by one stage (for example, S8 → S7 →... → S1) for each operation to downshift (−).

  The shift range control when the sequential mode is set uses, for example, the vehicle speed (output shaft speed) and the engine speed as parameters, and the target speed (engine speed) is set for each sequential shift range S1 to S8. Using the set map, based on the current vehicle speed and the position information of the sequential shift range selected by the shift lever operation, the target rotational speed is obtained with reference to the map, and the actual engine rotational speed is obtained as the target rotational speed. Is executed by a method of controlling the operating state of the first electric motor MG1 connected to the power distribution mechanism 2 so that the two coincide with each other. Further, in the map, the target rotational speed is set so that the sequential shift range S1 is the highest when the vehicle speed is the same, and becomes smaller toward the sequential shift range S8. For example, the sequential shift range is “ When the engine is downshifted from “S3” to “S2”, the engine speed increases. Further, when the shift range is upshifted from “S3” to “S4”, the engine speed is reduced.

-ECU-
As shown in FIG. 6, the ECU 100 includes a CPU 101, a ROM 102, a RAM 103, a backup RAM 104, and the like.

  The ROM 102 includes various programs including a program for executing a shift control for setting the gear stage of the automatic transmission 3 in accordance with the traveling state of the hybrid vehicle HV, in addition to the control related to the basic operation of the hybrid vehicle HV. It is remembered. Specific contents of this shift control will be described later.

  The CPU 101 executes arithmetic processing based on various control programs and maps stored in the ROM 102. The RAM 103 is a memory that temporarily stores calculation results of the CPU 101, data input from each sensor, and the like. The backup RAM 104 is a non-volatile memory that stores data to be saved when the engine 1 is stopped. is there.

  The CPU 101, ROM 102, RAM 103, and backup RAM 104 are connected to each other via a bus 106 and to an interface 105.

  The interface 105 of the ECU 100 includes an engine speed sensor 201, a throttle opening sensor 202 that detects the throttle valve opening of the engine 1, an input shaft speed sensor 203, an output shaft speed sensor 204, and an accelerator pedal opening. An accelerator opening sensor 205 for detecting, a shift position sensor 206 for detecting the position of the shift lever 81, a current sensor 207 for detecting a charge / discharge current of the battery 5, a battery temperature sensor 208, and the like are connected. A signal from the sensor is input to the ECU 100.

  The ECU 100 executes various controls of the engine 1 including throttle opening (intake amount) control, fuel injection amount control, ignition timing control and the like of the engine 1 based on the output signals of the various sensors described above.

  The ECU 100 outputs a solenoid control signal (instructed hydraulic signal) to the hydraulic control circuit 300 of the automatic transmission 3. Based on this solenoid control signal, the linear solenoid valve and the like of the hydraulic control circuit 300 are controlled, and the brakes B1 and B2 are engaged or released to a predetermined state so as to constitute a predetermined gear stage (Lo or Hi). The In addition, ECU 100 calculates the state of charge (SOC) based on the integrated value of the charge / discharge current detected by current sensor 207 in order to manage battery 5. Further, ECU 100 controls inverter 4, and the regeneration or power running (assist) of first motor generator MG <b> 1 and second motor generator MG <b> 2 is controlled by the control of inverter 4.

  Then, the ECU 100 executes the following “shift control”, “travel control”, and “torque down control”.

-Shift control-
First, the ECU 100 calculates the accelerator opening Ac based on the output signal of the accelerator opening sensor 205, and calculates the vehicle speed V based on the output signal of the output shaft rotational speed sensor 204, and determines the accelerator opening Ac and the vehicle speed. Based on V, the required torque Tr is obtained with reference to the map shown in FIG.

  Next, the target gear stage is calculated with reference to the shift map shown in FIG. 8 based on the vehicle speed V and the required torque Tr, and the rotation obtained from the output signals of the input shaft rotational speed sensor 203 and the output shaft rotational speed sensor 204. Whether the current gear stage of the automatic transmission 3 is determined based on the ratio of the numbers (output shaft rotational speed / input shaft rotational speed), and whether the speed change operation is necessary by comparing the target gear stage with the current gear stage. Determine whether or not.

  According to the determination result, when there is no need for shifting (when the target gear stage and the current gear stage are the same and the gear stage is appropriately set), a solenoid control signal (indicated hydraulic pressure) that maintains the current gear stage. Signal) to the hydraulic control circuit 300 of the automatic transmission 3.

  On the other hand, when the target gear stage and the current gear stage are different, shift control is performed. For example, the traveling state of the hybrid vehicle HV changes (for example, the vehicle speed changes) from the state in which the gear stage of the automatic transmission 3 is traveling in the “Hi” state, for example, from point A to point B shown in FIG. In this case, the target gear stage calculated from the shift map becomes “Lo”, and a solenoid control signal (instructed hydraulic signal) for setting the “Lo” gear stage is output to the hydraulic control circuit 300 of the automatic transmission 3. Then, at the same time as releasing the brake B1 as the friction engagement element, the shift from the Hi gear to the Lo gear (Hi → Lo down shift) is performed by engaging the brake B2.

  The map for calculating the required torque shown in FIG. 7 is a map obtained by empirically obtaining the required torque Tr by experiment / calculation using the vehicle speed V and the accelerator opening Ac as parameters, and is stored in the ROM 102 of the ECU 100. Has been.

  Further, the shift map shown in FIG. 8 uses the vehicle speed V and the required torque Tr as parameters, and has two regions (Lo region and Hi region) for obtaining an appropriate gear according to the vehicle speed V and the required torque Tr. It is a set map and is stored in the ROM 102 of the ECU 100. In the shift map of FIG. 8, the upshift line (shift line) is indicated by a solid line, and the downshift line (shift line) is indicated by a broken line. In addition, each switching direction of upshifting and downshifting is indicated by arrows in the figure.

  Even when the above-described sequential mode is selected, the automatic transmission 3 may be down when the shift state of the shift vehicle shown in FIG. Shift or upshift.

-Travel control-
The ECU 100 calculates the required torque Tr to be output to the ring gear shaft (output shaft) 21 with reference to the map shown in FIG. 7 based on the accelerator opening degree Ac and the vehicle speed V by the same processing as described above, and this required torque. The hybrid vehicle HV travels in a predetermined travel mode by drivingly controlling the engine 1 and the motor generators MG1, MG2 (inverter 4) so that the required power corresponding to Tr is output to the ring gear shaft 21.

  For example, in a region where the engine efficiency is low, such as when starting or running at low speed, the operation of the engine 1 is stopped, and power corresponding to the required power is transferred from the second motor generator MG2 to the ring gear shaft 21 via the automatic transmission 3. Output. During normal travel, the engine 1 is driven so that power commensurate with the required power is output from the engine 1, and the rotation speed of the engine 1 is controlled by the first motor generator MG1 so as to achieve optimum fuel consumption.

  When assisting the torque by driving the second motor generator MG2, the gear stage of the automatic transmission 3 is set to Lo and the torque applied to the ring gear shaft (output shaft) 21 is increased when the vehicle speed V is low. In the state where the vehicle speed V increases, the gear stage of the automatic transmission 3 is set to Hi, and the rotational speed of the second motor generator MG2 is relatively decreased to reduce the loss, thereby executing efficient torque assist. To do. Further, the operation of the second motor generator MG2 is stopped, and the torque (direct torque) transmitted directly from the engine 1 to the ring gear shaft 21 via the power distribution mechanism 2 while taking the reaction force of the engine torque by the first motor generator MG1. ) Is also executed.

  The ECU 100 normally supplies an equal power command to the second motor generator MG2 so that the input torque of the automatic transmission 3 becomes equal power (input shaft speed × input torque = constant). MG2 is controlled with equal power.

-Torque down control-
First, in the hybrid vehicle HV, when the torque of the second motor generator MG2 is reduced, excessive power is generated because power consumption is reduced. In order to absorb the surplus power amount, it is necessary to implement either a method of reducing the power generation amount or charging the battery 5. However, as described above, in order to reduce the power generation amount, the reaction of the engine torque is reduced. Although it is necessary to reduce the torque of the first motor generator MG1 responsible for the force, if the torque of the first motor generator MG1 is reduced, engine overspeed may be caused. Can not do it. Further, in the case of the method of absorbing the surplus power amount by charging the battery 5, the method cannot be performed when there is a charging limitation of the battery 5 (a limitation due to temperature, a limitation due to SOC, or the like).

  For this reason, if torque reduction cannot be performed during gear shifting, blowing of the second motor generator MG2, which is the gear to be shifted, cannot be restricted. Therefore, the rotation speed of the second motor generator MG2 and the engagement target rotation speed (target The friction engagement element is engaged in a state where there is a differential rotation with respect to the synchronous rotation speed of the gear stage, and an engagement shock may occur.

  Considering such points, in this example, the torque reduction of the second motor generator MG2 can be performed during the shift of the automatic transmission 3 without being affected by the battery limit or the engine speed. A specific example of the control will be described with reference to the flowchart of FIG. The control routine of FIG. 9 is repeatedly executed in the ECU 100 every predetermined time (for example, several milliseconds).

  First, in step ST10, it is determined whether or not the shift of the automatic transmission 3 has been started. If the determination result is affirmative, the process proceeds to step ST20. Specifically, when the traveling state of the hybrid vehicle HV changes from the state in which the gear stage of the automatic transmission 3 is traveling in the state of “Hi” or “Lo” and crosses the shift line in FIG. Since a shift (downshift or upshift) is started, the process proceeds to step ST20 at the start of the shift. If the determination result in step ST10 is negative, the process returns.

  In step ST20, torque reduction amount T1 of second motor generator MG2 is determined. Specifically, the required torque Tr is calculated by referring to the map shown in FIG. 7 based on the accelerator opening degree Ac and the vehicle speed V by the same processing as described above, and the map of FIG. 10 is calculated based on the required torque Tr. The torque-down amount T1 is determined with reference to the reference. Here, the torque reduction during the shift is performed for the purpose of reducing the shift shock, reducing the load on the frictional engagement elements (brakes B1 and B2) of the automatic transmission 3, and preventing the motor from over-rotating.

  The torque-down amount calculation map in FIG. 10 is a map of values obtained by experiments / calculations or the like that can reduce the shift shock and the load of the friction engagement element using the required torque Tc as a parameter. Is stored in the ROM 102. In the map of FIG. 10, the torque reduction amount T1 is set to a larger value as the required torque Tr increases in accordance with the required torque Tr. The torque reduction amount T1 may be calculated according to an arithmetic expression using the above-described required torque Tr.

  Next, in step ST30, the generated charge amount W1 generated when the torque reduction amount T1 determined in step ST20 is performed is predicted. The generated charge amount W1 will be described. First, in the drive device of the hybrid vehicle HV, the power balance is normally controlled to be zero when the generator power generation amount, the battery charge / discharge amount, and the motor consumption amount are all added, so that the torque is reduced by the second motor generator MG2. Then, the torque reduction is generated as it is as the power generation amount (charge amount). Since the generated power generation amount W1 can be expressed as [generated power generation amount W1 = motor rotational speed × torque down amount T1], using this calculation formula, the motor rotational speed (the rotational speed of the second motor generator MG2) and The generated power generation amount W1 is calculated based on the torque down amount T1 obtained in step ST20. The motor rotation speed is calculated based on, for example, an output signal from the input shaft rotation speed sensor 203.

  Here, the motor rotation speed changes during the shift. In addition, since the torque down amount may be changed according to the degree of shift progress, or a torque down amount larger than usual may be required to suppress motor blowing, in this example, the generated power generation amount is calculated using the above-described arithmetic expression. W1 is always calculated. The generated power generation amount W1 may be calculated using a variable map that parameters the motor rotation speed and the torque reduction amount.

  In step ST40, it is determined whether or not the battery charge permission amount (Win) determined from the battery temperature and SOC detected by the battery temperature sensor 208 is smaller than the generated power generation amount W1 calculated in step ST30. If the determination result is affirmative (battery charge permission amount <W1), the process proceeds to step ST50. When the determination result of step ST40 is negative (battery charge permission amount ≧ W1), the process proceeds to step ST80. It should be noted that the battery charge permission amount used in the determination process of step ST40 is that the charge amount increases due to a shift in the equal power control in the inertia phase during the shift, and the charge amount increases due to a decrease in the load of auxiliary equipment such as an air conditioner. It may be calculated in consideration of such margins. The battery charge permission amount may be calculated in consideration of the loss of the motor, inverter, battery, and the like.

  When the above step ST40 is affirmative and the process of step ST50 is executed, it is known that the generated charge amount W1 cannot be absorbed only by the battery 5, and therefore the battery 5 cannot absorb it in step ST50. The engine speed increase amount N1 when the power generation amount by the first motor generator MG1 is reduced by the amount of charge is predicted.

  The engine speed increase N1 is estimated (predicted) from N1 = [(current engine torque−reaction force (torque) decrease due to MG1 torque reduction) × unit time ÷ engine moment of inertia]. Here, the current engine torque is estimated from the engine operating condition or estimated from the MG1 torque. The reaction force decrease due to MG1 torque reduction is estimated from [(generated charge amount / MG1 rotation speed) × gear ratio]. The unit time is a processing cycle of the ECU 100.

  In step ST60, the current engine speed is read from the output signal of the engine speed sensor 201. If the engine speed is increased by N1 calculated in step ST50 from the current engine speed, the increase is detected. It is determined whether or not the engine speed (engine speed + N1) exceeds the engine upper limit engine speed Nmax. When the determination result of step ST60 is affirmative ([engine speed + N1]> Nmax), the process proceeds to step ST70. When the determination result of step ST60 is negative ([engine speed + N1] ≦ Nmax), the process proceeds to step ST80. The engine upper limit rotational speed Nmax includes the hardware limit / control limit of the engine 1 itself, the upper limit rotational speed of the first motor generator MG1, the upper limit rotational speed (gear rotational speed, etc.) of the rotating body of the driving force transmission system, and the like. Decided in consideration.

  In step ST70, the drive efficiency of the second motor generator MG2 is reduced (loss increased), and the torque is reduced by the torque reduction amount T1 obtained in step ST20. As a method of reducing the driving efficiency of the second motor generator MG2, there are a method of increasing the carrier frequency of the inverter 4 to increase the switching loss, and a method of shifting the phase of the driving current of the second motor generator MG2 with respect to the rotor magnetic field. And so on.

  On the other hand, if the determination result in step ST60 is negative, it is determined that the generated charge amount W1 due to torque reduction can be absorbed, and the torque of the second motor generator MG2 is the same as in normal torque control. The torque is reduced by lowering the command value and reducing the drive current (step ST80).

  As described above, according to the control of this example, the generated charge amount W1 generated when the torque of the second motor generator MG2 is reduced during the shift is predicted, and the generated charge amount W1 is calculated from the battery charge permission amount. If the engine 1 is likely to over-rotate, the drive efficiency of the second motor generator MG2 is reduced to reduce the torque, so the power consumption does not decrease even if the torque is reduced. The power balance does not change. As a result, it is possible to perform torque reduction during the shift without being affected by the battery limit or the engine speed, and the deterioration of the shift shock can be prevented.

-Other embodiments-
In the above example, all of the torque reduction required during the shift is performed by a method of reducing the drive efficiency of the second motor generator MG2, but the present invention is not limited to this, and the second motor generator MG2 is not limited to this. In the feasible range (condition), torque reduction is performed by reducing the drive current as much as possible within the feasible range (conditions), and the torque reduction amount of the shortage is reduced by the second motor generator MG2. You may perform control which compensates with the torque reduction by drive efficiency fall. In this case, a reduction in driving efficiency, that is, motor loss can be reduced, so that deterioration in fuel consumption can be reduced.

  Here, as a method of reducing the drive efficiency of the second motor generator MG2, the first drive efficiency reduction method of reducing the drive efficiency by increasing the carrier frequency of the inverter 4 and increasing the switching loss, and , A second driving efficiency reduction method for reducing the driving efficiency by shifting the phase of the driving current of the second motor generator MG2 with respect to the rotor magnetic field, and the first driving efficiency reduction method and the second driving efficiency reduction method The third driving efficiency lowering method for lowering the driving efficiency in both of the first driving efficiency lowering method, the second driving efficiency lowering method, or the third driving efficiency lowering method. , Any one of the methods may be selected to reduce the driving efficiency of the second motor generator MG2 to reduce the torque during the shift. There. Specifically, for example, when the torque reduction amount T1 required during the shift is small and the torque reduction can be achieved only by the first drive efficiency reduction method or the second drive efficiency reduction method, the first drive efficiency Either the reduction method or the second drive efficiency reduction method is selected to reduce the drive efficiency of the second motor generator MG2, and if the torque down amount T1 is large, the third drive efficiency reduction method is selected. Thus, the driving efficiency of the second motor generator MG2 is reduced.

  When either one of the first and second driving efficiency lowering methods is selected, the current temperatures of the inverter 4 and the second motor generator MG2 are detected by temperature sensors or the like, respectively, and the temperature detection result is displayed. Based on the inverter 4 or the second motor generator MG2, a method (first or second driving efficiency lowering method) in which the amount of heat generation with a larger margin with respect to the allowable temperature is selected to select the second motor generator MG2 is selected. The driving efficiency may be lowered. For example, when the inverter 4 has a margin for the allowable temperature, the first driving efficiency reduction method is selected, and when the second motor generator MG2 has a margin for the allowable temperature, the second driving is performed. The efficiency reduction method is selected to reduce the driving efficiency of the second motor generator MG2.

  Further, when the third drive efficiency lowering method is selected, similarly, the current temperatures of the inverter 4 and the second motor generator MG2 are detected, and when the inverter 4 has a margin for the allowable temperature, the inverter 4 When the second motor generator MG2 has a margin for the allowable temperature, control is performed to set the heat generation amount of the second motor generator MG2 small and the heat generation amount of the second motor generator MG2 small. The drive efficiency of the second motor generator MG2 may be reduced by a control that sets the amount large and sets the amount of heat generated by the inverter 4 small.

  In this way, by controlling the decrease in drive efficiency in consideration of the heat generation amount of the inverter 4 and the second motor generator MG2, the torque reduction during the shift is performed while suppressing an increase in the thermal load of the inverter 4 and the second motor generator MG2. can do.

  In the above example, an example in which the present invention is applied to control of a vehicle equipped with an automatic transmission with two forward shifts is shown, but the present invention is not limited to this, and other examples such as forward four shifts, etc. The present invention can also be applied to control of a vehicle equipped with a planetary gear type automatic transmission having an arbitrary speed.

  In the above example, the example in which the present invention is applied to the control of a vehicle equipped with a gasoline engine has been shown. However, the present invention is not limited to this, and the present invention is also applicable to the control of a vehicle equipped with another engine such as a diesel engine. Applicable. Furthermore, the present invention is not limited to an FR (front engine / rear drive) type vehicle, but can also be applied to control of an FF (front engine / front drive) type vehicle or a four-wheel drive vehicle.

It is a schematic structure figure showing an example of a hybrid vehicle to which the present invention is applied. It is a schematic block diagram of the automatic transmission mounted in the hybrid vehicle of FIG. It is an operation | movement table | surface of the automatic transmission shown in FIG. It is a circuit block diagram which shows a part of hydraulic control circuit of an automatic transmission. It is a figure which writes and shows the principal part perspective view (a) of a shift operation apparatus, and the shift gate (b) of a shift operation apparatus. It is a block diagram which shows the structure of control systems, such as ECU. It is a figure which shows an example of the map used for request | requirement torque calculation. It is a figure which shows an example of the shift map used for shift control. It is a flowchart which shows an example of the torque down control which ECU performs. It is a figure which shows the map for torque reduction amount calculation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Power distribution mechanism 21 Ring gear shaft 3 Automatic transmission 30 Input shaft 33 Output shaft 300 Hydraulic control circuit B1, B2 Brake (friction engagement element)
4 Inverter 5 Battery (power storage device)
7 Drive Wheel 8 Shift Operation Device S Sequential Position MG1 First Motor Generator MG2 Second Motor Generator 100 ECU

Claims (7)

An engine and an electric motor that output a driving force for traveling; a power storage device that can charge electric power generated by the electric motor and supply electric power to the electric motor; and a transmission, and the motive power from the electric motor is supplied to the transmission. A vehicle control device that outputs to a drive wheel via
A vehicle control apparatus comprising torque down control means for temporarily increasing the loss of the electric motor and decreasing the driving efficiency of the electric motor during shifting of the transmission. The vehicle control device according to claim 1,
The torque-down control means performs torque-down only by lowering the driving efficiency of the motor when the control for lowering the driving current of the motor cannot be performed during shifting of the transmission. Control device. The vehicle control device according to claim 1,
The torque down control means performs torque down by reducing the drive current of the electric motor within a feasible range when the control to reduce the drive current of the electric motor can be executed during the shift of the transmission. A control device for a vehicle, wherein a deficient amount of torque reduction is compensated by torque reduction due to the reduction in driving efficiency. In the control apparatus of the vehicle as described in any one of Claims 1-3,
A plurality of methods for reducing the drive efficiency are set, and the torque down control means selects any one of the plurality of drive efficiency reduction methods to reduce the drive efficiency of the electric motor. A vehicle control device characterized by the above. The vehicle control device according to claim 4, wherein
A first drive efficiency reduction method for reducing the drive efficiency of the motor by increasing the carrier loss of the inverter of the motor and increasing the switching loss, and the motor by shifting the phase of the drive current of the motor with respect to the rotor magnetic field Or a third driving efficiency lowering method for reducing the driving efficiency of the motor by both the first driving efficiency lowering method and the second driving efficiency lowering method. A vehicle control device that performs torque reduction by selecting any one of the methods. The vehicle control device according to claim 5, wherein
Detecting each temperature of the inverter and the electric motor, and controlling the decrease in the driving efficiency so that the heat generation amount of the inverter or the electric motor having a larger margin with respect to the allowable temperature is increased based on the temperature detection result. A vehicle control device characterized by the above. In the control apparatus of the vehicle as described in any one of Claims 1-6,
A vehicle control device having a function of selecting a sequential mode for manually performing a shift operation.

Images