JP2015205532A - Hybrid-vehicular control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start an engine appropriately during an EV travel, and expand a possible range of the EV travel that uses output of two motors.SOLUTION: A control apparatus is for use in a hybrid vehicle that includes: a power division mechanism for performing a differential operation using a carrier linked with an engine, a sun-gear linked with a first motor, and a link gear linked with a drive shaft and a second motor; a brake mechanism for selectively stopping rotation of the engine and carrier; and transmission means for converting output torque of the second motor to transmit to the drive shaft. In the control apparatus, when the hybrid vehicle travels on the output torque of the first and second motors with the revolution of the engine stopped, and when the engine is started (S1), the engine is started (S4) with a transmission ratio of the transmission means set so that the output torque of the second motor is large in relation to a vehicle speed (S2).

Description

  The present invention relates to a control device that controls traveling of a hybrid vehicle that uses an engine and a motor as driving force sources.

  An invention relating to a hybrid vehicle is described in Patent Document 1. The hybrid vehicle described in Patent Document 1 includes an engine, a first motor, a second motor, an output shaft, a planetary gear unit, and braking means. The first motor is a motor that generates electric power by the input torque. The second motor is a motor that is driven by supplying a current. The output shaft is configured to be rotated by driving the second motor. In the planetary gear unit, the sun gear and the first motor are connected. The ring gear and the output shaft are connected. The carrier and the engine are connected. The braking means is configured to stop the rotation of the carrier and the engine when engaged.

  Patent Document 2 describes an invention relating to an engine, a motor / generator, and a control device for a hybrid vehicle including an automatic transmission that shifts and outputs power from the engine or the motor / generator. The hybrid vehicle control device described in Patent Document 2 switches between a first travel mode in which the engine is started less frequently and a second travel mode in which the engine is started more frequently than the first travel mode. The shift control based on the first shift pattern in the first travel mode and the shift control based on the second shift pattern in the second travel mode are executed. The first shift pattern and the second shift pattern in each shift control are set to be different from each other.

  In Patent Document 3, a power distribution and integration mechanism including an engine, a first motor, a second motor, and a planetary gear mechanism, and the rotational speed of the rotary shaft of the second motor are shifted in two stages and output. An invention relating to a control device for a hybrid vehicle including a transmission is described. In the control apparatus for a hybrid vehicle described in Patent Document 3, the transmission starts when the engine starts with the rotation speed of the rotation shaft of the second motor being reduced at a relatively large reduction ratio, and the transmission is the second. It is configured to set a cranking torque that can avoid resonance at the time of starting the engine in each case where the engine is started in a state where the rotational speed of the motor rotation shaft is decelerated at a relatively small reduction ratio. ing.

Japanese Patent Laid-Open No. 08-295140 JP 2013-95158 A JP 2009-248619 A

  As in the hybrid vehicle described in Patent Document 1 above, in the configuration including the braking means for stopping the rotation of the carrier and the engine, the engine is stopped from the combustion operation and traveled by the output torque of the motor (EV travel). ), The vehicle can be driven efficiently by the output torques of the two motors by stopping and fixing the rotation of the output shaft of the engine and the carrier by the braking means. Therefore, the driving force during EV traveling can be improved, and the energy efficiency during EV traveling can be improved.

  On the other hand, in the hybrid vehicle having the above-described configuration, when the engine is started during EV traveling by the output torque of the two motors with the engine output shaft fixed as described above, The engine is cranked by the torque of the first motor connected to the sun gear while releasing the fixation. In that case, the first motor outputs a negative torque in the direction of moving the vehicle backward. Therefore, when the driving force of the vehicle falls due to the negative torque output from the first motor, the driver may feel uncomfortable or shocked. In order to prevent such a sense of incongruity or occurrence of a shock, it is necessary to output a torque for compensating for a drop in the driving force by offsetting the negative torque as described above by the second motor.

  As described above, when the engine is started during EV traveling by the output torque of the two motors, in order to prevent a sense of incongruity and shock, the engine is started in a region where compensation for negative torque by the second motor is possible. Need to do. Therefore, the region in which EV traveling by the output torque of the two motors can be appropriately executed is limited.

  The present invention has been conceived by paying attention to the above technical problem, and is intended to control a hybrid vehicle capable of stopping the rotation of the engine and running EV by the output torque of the two motors. An object of the present invention is to provide a control device for a hybrid vehicle that can appropriately start an engine during traveling and expand an area in which EV traveling by the output torque of two motors is possible.

  To achieve the above object, the present invention provides a first rotating element to which an engine is connected, a second rotating element to which a first motor is connected, and a third rotation to which a drive shaft and a second motor are connected. A power split mechanism that performs differential action by elements, braking means that selectively stops the rotation of the output shaft of the engine and the first rotating element, and the output torque of the second motor are shifted and transmitted to the drive shaft. In the hybrid vehicle control device, the hybrid vehicle is driven at a predetermined vehicle speed by the output torque of both the first motor and the second motor in a state where the rotation of the output shaft is stopped by the braking means. When the engine is started while traveling at a speed of 2, the speed change means is set so that the output torque of the second motor corresponding to the vehicle speed becomes relatively large. Set the definitive gear ratio, the control apparatus for a hybrid vehicle, characterized by being configured to execute a control for starting the engine.

  In the hybrid vehicle control device according to the present invention, the hybrid vehicle to be controlled is provided with speed change means capable of amplifying the output torque of the second motor. In such a hybrid vehicle, when the engine is started during EV traveling with the output torque of both the first motor and the second motor with the engine stopped, the output torque of the second motor is relatively low. The speed ratio of the speed change means is set so as to increase. Then, control for starting the engine is executed in a state where such a gear ratio is set. Therefore, according to the hybrid vehicle control apparatus of the present invention, when the engine is started during EV traveling by the output torque of both the first motor and the second motor, the output torque of the second motor is increased by the speed change means. In such a state, the engine can be cranked by the output torque of the first motor. Therefore, even if the driving force that is borne by the first motor when starting the engine is reduced, the reduction in the driving force can be easily compensated by the output torque of the second motor. As a result, it is possible to suppress the torque fluctuation when starting the engine and to start the engine appropriately. Further, as the output torque of the second motor is increased, the range in which the driving force at the time of engine start can be compensated by the output torque of the second motor is expanded. Therefore, it is possible to expand a region where appropriate EV traveling can be performed by the output torque of both the first motor and the second motor.

It is a figure which shows an example of the power train of the hybrid vehicle which can be made into object by this invention. It is a flowchart for demonstrating an example of the control performed with the control apparatus which concerns on this invention. FIG. 3 is a diagram for explaining control for selecting a gear position of a transmission means when the control shown in the flowchart of FIG. 2 is executed.

  Next, the present invention will be specifically described with reference to the drawings. FIG. 1 shows an example of a power train in a hybrid vehicle Ve that can be used in the present invention. The hybrid vehicle Ve includes an engine (ENG) 1, a first motor / generator (MG1) 2, and a second motor / generator (MG2) 3 as driving force sources. The power output from the engine 1 is divided and transmitted to the first motor / generator 2 side and the drive shaft 5 side by the power split mechanism 4. The electric power generated by the first motor / generator 2 is supplied to the second motor / generator 3, and the power output from the second motor / generator 3 can be added to the drive shaft 5. .

  The engine 1 is configured to electrically control its output adjustment, starting and stopping operations. For example, in the case of a gasoline engine, throttle opening, fuel supply amount, execution and stop of ignition, ignition timing, and the like are electrically controlled.

  Each of the first motor / generator 2 and the second motor / generator 3 is a motor having a power generation function, and is constituted by, for example, a permanent magnet type synchronous motor. Each of the first motor / generator 2 and the second motor / generator 3 is connected to a battery (not shown) via an inverter (not shown), and is used as a rotational speed, torque, or motor. Switching between functions and functions as a generator is configured to be electrically controlled.

  The power split mechanism 4 is constituted by a differential mechanism having three rotating elements. Specifically, it is constituted by a planetary gear mechanism having a sun gear 6, a ring gear 7, and a carrier 8. In the example shown in FIG. 1, a single pinion type planetary gear mechanism is used.

  The planetary gear mechanism that constitutes the power split mechanism 4 is disposed on the same rotational axis as the output shaft 1 a of the engine 1. The first motor / generator 2 is connected to the sun gear 6 of the planetary gear mechanism. The first motor / generator 2 is disposed adjacent to the power split mechanism 4 on the side opposite to the engine 1 and rotates integrally with the rotor 2a of the first motor / generator 2. Is connected to the sun gear 6. A ring gear 7 which is an internal gear is arranged concentrically with the sun gear 6. The pinion gear meshing with the sun gear 6 and the ring gear 7 is held by the carrier 8 so that it can rotate and revolve. An input shaft 4 a of the power split mechanism 4 is connected to the carrier 8, and an output shaft 1 a of the engine 1 is connected to the input shaft 4 a via a one-way brake 9. The input shaft 4a and the one-way brake 9 may be directly connected, but in the configuration example shown in FIG. 1, a damper 10 and a clutch 11 are provided between the input shaft 4a and the one-way brake 9.

  The one-way brake 9 is provided between the output shaft 1a or the carrier 8 and a fixing member 12 such as a housing. And when the torque of the reverse direction to the rotation direction of the engine 1 acts on the output shaft 1a or the carrier 8, it is comprised so that the rotation may be stopped. By using such a one-way brake 9, the rotation of the output shaft 1a or the carrier 8 can be stopped according to the direction of the torque. Therefore, when performing so-called EV travel that travels with the power of the first motor / generator 2 and the second motor / generator 3, it is not necessary to perform special control of the engagement mechanism such as a clutch or a brake. As described above, in the configuration of the hybrid vehicle Ve shown in FIG. 1, the rotation of the output shaft 1 a of the engine 1 or the input shaft 4 a of the power split mechanism 4 is selectively stopped by the one-way brake 9. . Accordingly, in the example shown in FIG. 1, the one-way brake 9 corresponds to the braking means in the present invention. The braking means in the present invention is not limited to the one-way brake 9 as described above. For example, the braking means in this invention can also be comprised by the dog brake which mechanically engages a rotation member and a fixing | fixed part.

  The clutch 11 is for connecting the engine 1 to a power transmission system from the driving force source to the driving wheels, or for disconnecting the engine 1 from the power transmission system. That is, the clutch 11 selectively connects the output shaft 1 a of the engine 1 and the carrier 8. For example, the clutch 11 is constituted by a friction clutch that engages rotating members that rotate relative to each other by a frictional force.

  An external gear drive gear 13 is integrally formed on the outer peripheral portion of the ring gear 7 of the planetary gear mechanism. A countershaft 14 is arranged in parallel with the rotation axis of the power split mechanism 4 and the first motor / generator 2. A counter driven gear 15 that meshes with the drive gear 13 is attached to the central portion of the counter shaft 14 so as to rotate integrally. At one end (left side in FIG. 1) of the counter shaft 14, a first counter drive gear 18 that meshes with a ring gear 17 of a differential gear 16 that is a final reduction gear is configured to rotate integrally with the counter shaft 14. Is attached. A second counter drive gear 19 that meshes with a second reduction gear 22 described later is attached to the other end (right side in FIG. 1) of the counter shaft 14 so as to rotate integrally with the counter shaft 14. Yes. Accordingly, the ring gear 7 of the power split mechanism 4 is connected to the drive shaft 5 via the gear train including the drive gear 13, the counter shaft 14, the counter driven gear 15, and the first counter drive gear 18, and the differential gear 16. It is connected so that power can be transmitted.

  The torque output from the second motor / generator 3 can be added to the torque transmitted from the power split mechanism 4 to the drive shaft 5. Specifically, the second motor / generator 3 is arranged in parallel with the counter shaft 14. A rotor shaft 3 b that rotates integrally with the rotor 3 a of the second motor 3 is connected to the drive gear 13 and the differential gear 16 via the speed change mechanism 20.

  The speed change mechanism 20 includes a first reduction gear 21, a second reduction gear 22, and a switching clutch 23. The first reduction gear 21 is supported near the tip (right side in FIG. 1) of the rotor shaft 3b so as to be able to rotate relative to the rotor shaft 3b. The first reduction gear 21 and the counter driven gear 15 are engaged with each other. The second reduction gear 22 is supported further on the tip (right end in FIG. 1) of the rotor shaft 3b than the first reduction gear 21 so as to be able to rotate relative to the rotor shaft 3b. And this 2nd reduction gear 22 and the above-mentioned 2nd counter drive gear 19 have meshed | engaged.

  The switching clutch 23 can be constituted by a meshing clutch such as a dog clutch or a synchronizer. FIG. 1 shows an example in which the switching clutch 23 is configured by a synchronizer. Specifically, the switching clutch 23 includes a spline formed on the boss portion of the first reduction gear 21 or a spline formed on the boss portion of the second reduction gear 22, and a spline formed on the hub of the rotor shaft 3b. The first reduction gear 21 or the second reduction gear 22 and the rotor shaft 3b are selectively connected by fitting the sleeve 23a to the rotor 23a.

  The first reduction gear 21 is configured by a gear having a smaller diameter than the counter driven gear 15. Therefore, in a state where the rotor shaft 3b and the first reduction gear 21 are connected by the switching clutch 23, the torque output from the second motor / generator 3 is decelerated, and the counter driven gear 15 and the counter shaft 14 are reduced. Is transmitted to. That is, the output torque of the second motor / generator 3 is amplified and transmitted to the counter driven gear 15 and the counter shaft 14.

  Further, the second reduction gear 22 is constituted by a gear that is the same as or smaller in diameter than the second counter drive gear 19. Therefore, in a state where the rotor shaft 3b and the second reduction gear 22 are connected by the switching clutch 23, the torque output from the second motor / generator 3 is left as it is or the rotational speed thereof is increased, and the counter driven gear. 15 and the countershaft 14. Therefore, in this case, the speed ratio set by the speed change mechanism 20 is smaller than when the rotor shaft 3b and the first reduction gear 21 are coupled as described above.

  Thus, the speed change mechanism 20 is configured to change the output torque of the second motor / generator 3 and transmit it to the drive shaft 5 side. Then, by connecting the rotor shaft 3b and the first reduction gear 21 by the switching clutch 23, a gear ratio at which the output torque of the second motor becomes relatively large, that is, the first speed (1st) is set. On the other hand, by connecting the rotor shaft 3b and the second reduction gear 22 by the switching clutch 23, the gear ratio at which the output torque of the second motor is relatively reduced, that is, the second speed having a smaller gear ratio than the first speed. (2nd) is set. Therefore, the speed change mechanism 20 corresponds to the speed change means in the present invention.

  Note that the speed change means in the present invention is not limited to the speed change mechanism 20 composed of a plurality of gear trains as described above. The speed change means in the present invention may be any means that can change the speed ratio so as to amplify the output torque of the second motor / generator 3. For example, the speed change means in the present invention can be constituted by a continuously variable transmission constituted by a belt and a pulley.

  Operation control of the engine 1 as described above, rotation control of the first motor / generator 2 and the second motor / generator 3, operation control of engagement and disengagement of the clutch 11, and switching operation of the switching clutch 23 in the transmission mechanism 20. An electronic control unit (ECU) 24 for executing control is provided. The electronic control unit 24 is configured mainly with a microcomputer, and is configured to perform an operation using input data and data stored in advance, and output the operation result as a control command signal. Yes.

  The hybrid vehicle Ve to be used in the present invention effectively uses the engine 1, the first motor / generator 2 and the second motor / generator 3 constituting the driving force source as described above, so that the energy efficiency or the fuel efficiency can be improved. Is controlled to be good. Specifically, “HV mode” in which the hybrid vehicle Ve is driven by at least the output of the engine 1 and at least one of the motors of the first motor / generator 2 and the second motor / generator 3 by stopping the operation of the engine 1. “EV mode” in which the hybrid vehicle Ve travels by the output of the generator is appropriately selected according to the travel state of the hybrid vehicle Ve.

  Among the travel modes described above, in particular, the “EV mode” is a “first EV mode” in which the hybrid vehicle Ve travels by the output of one of the first motor generator 2 and the second motor generator 3. And “second EV mode” in which the hybrid vehicle Ve is driven by the outputs of both the first motor / generator 2 and the second motor / generator 3. These “first EV mode” and “second EV mode” are appropriately selected according to the traveling state of the hybrid vehicle Ve.

  For example, in the “first EV mode”, the hybrid vehicle Ve is driven only by the output of the second motor / generator 3. In the “first EV mode”, the second motor / generator 3 is controlled to rotate in the forward direction (rotation direction of the output shaft 1a of the engine 1) as a motor and output torque. Then, the driving force is generated by the output torque of the second motor / generator 3, and the hybrid vehicle Ve is caused to travel.

  In the “second EV mode”, the hybrid vehicle Ve is driven by the outputs of both the first motor / generator 2 and the second motor / generator 3. In the “second EV mode”, the first motor / generator 2 is controlled to rotate in the negative direction (the direction opposite to the rotation direction of the output shaft 1a of the engine 1) as a motor and output torque. The second motor / generator 3 is controlled to rotate in the positive direction as a motor and output torque. Then, the driving force is generated by the output torque of the first motor / generator 2 and the output torque of the second motor / generator 3, and the hybrid vehicle Ve is caused to travel. In this case, since the torque in the negative direction acts on the output shaft 1a of the engine 1, the one-way brake 9 is engaged. Therefore, the hybrid vehicle Ve can be efficiently driven by the output torques of both the first motor / generator 2 and the second motor / generator 3 while the rotation of the engine 1 is stopped and fixed.

  When the hybrid vehicle Ve is traveling in the “second EV mode” as described above, for example, when the engine 1 is started by requiring a larger driving force, the output torque of the first motor / generator 2 is output. To crank the engine 1. In this case, the first motor / generator 2 outputs a driving torque for generating the driving force of the hybrid vehicle Ve together with the second motor / generator 3. For this reason, when torque for cranking the engine 1 is output by the first motor / generator 2, the driving torque of the hybrid vehicle Ve is reduced by that amount. As a result, the driver may feel uncomfortable or shocked.

  In response to the decrease in the driving force as described above, the decrease in the driving torque output from the first motor / generator 2 is compensated by the output torque of the second motor / generator 3, thereby suppressing the decrease in the driving force. Thus, the engine 1 can be appropriately started. On the other hand, in order to appropriately execute such compensation of the driving force by the second motor / generator 3, it is necessary to execute it in a region where there is a margin in the output of the second motor / generator 3. Therefore, if there is no margin in the output of the second motor / generator 3, the region in which the hybrid vehicle Ve can travel appropriately in the “second EV mode” is limited.

  Therefore, the control device according to the present invention can appropriately start the engine 1 while traveling in the “second EV mode” with the hybrid vehicle Ve configured as described above being controlled, and the “second EV” In order to secure a region where the vehicle can travel in the “mode”, the control shown in the following example is executed.

  FIG. 2 is a flowchart showing an example of the control executed by the control device according to the present invention, in which the “second EV mode” is selected and the outputs of both the first motor / generator 2 and the second motor / generator 3. The state where the hybrid vehicle Ve is traveling by torque is assumed to be executed. The routine shown in the flowchart of FIG. 2 is repeatedly executed every predetermined short time.

  In step S1, it is determined whether or not there is a start request for the engine 1. If it is determined negative in this step S1 because there is no start request for the engine 1 yet, such as when traveling while satisfying the required driving force in the “second EV mode”, the subsequent control is executed. This routine is temporarily terminated.

  On the other hand, when the required driving force is increased or the like, when there is a start request for the engine 1 and the determination is affirmative in step S1, the process proceeds to step S2. Then, a gear stage (gear stage) of the transmission mechanism 20 capable of transmitting the output torque of the second motor / generator 3 at the maximum is selected, and shift control for setting the gear stage is executed.

Specifically, corresponding to the vehicle speed of the hybrid vehicle Ve traveling in the “second EV mode”,
The gear position in the speed change mechanism 20 is set so that the output torque of the second motor / generator 3 becomes relatively large in the state of the vehicle speed. For example, as shown in FIG. 3, when the hybrid vehicle Ve is traveling at the vehicle speed v1, an output transmitted to the drive wheel 5 side is output when the shift speed of the transmission mechanism 20 is the first speed (1st). In contrast to p11, the output transmitted to the drive wheel 5 when the gear position of the speed change mechanism 20 is the second speed (2nd) is an output p12 smaller than the output p11. Therefore, in this case, the first speed is set by the speed change mechanism 20. On the other hand, when the hybrid vehicle Ve is traveling at the vehicle speed v2, the output transmitted to the drive wheel 5 side when the gear position of the transmission mechanism 20 is the first speed (1st) is the output p21. The output transmitted to the drive wheel 5 when the gear position of the transmission mechanism 20 is the second speed (2nd) is an output p22 that is greater than the output p21. Therefore, in this case, the speed change mechanism 20 sets the second speed. In FIG. 3, a line L0 indicates the relationship between the rotation speed of the second motor / generator 3 and the output. A line L1 indicates the relationship between the rotational speed of the second motor / generator 3 and the vehicle speed when the gear position of the transmission mechanism 20 is the first speed (1st). A line L2 indicates the relationship between the rotational speed of the second motor / generator 3 and the vehicle speed when the gear position of the transmission mechanism 20 is the second speed (2nd).

  When the shift control of the transmission mechanism 20 is executed in step S2 as described above, the process proceeds to step S3, and it is determined whether or not the shift control is completed. If a negative determination is made in step S3 because the speed change control has not yet been completed, the process returns to step S2, and the control in step S2 and step S3 is repeatedly executed.

  On the other hand, if the shift control of the transmission mechanism 20 is completed and a positive determination is made in step S3, the process proceeds to step S4. Then, start control of the engine 1 is executed. Specifically, the engine 1 is cranked by the output torque of the first motor / generator 2. When the rotational speed of the output shaft 1a of the engine 1 reaches a predetermined rotational speed due to cranking, the combustion operation of the engine 1 is started.

  While the start control of the engine 1 is being executed in step S4, the speed change mechanism 20 maintains the speed set in step S2. There may be a case where the optimum gear position to be set by the transmission mechanism 20 changes after the start of the shift control of the transmission mechanism 20 in step S2 until the start control of the engine 1 is completed. On the other hand, since the gear position of the transmission mechanism 20 is fixed until the start control of the engine 1 is completed, the start delay of the engine 1 due to the shift being performed during the start control of the engine 1 is prevented. It can be avoided. The maintenance of the shift speed as described above is canceled when the engine 1 is completely started.

  When the start control of the engine 1 is completed in step S4 as described above, this routine is once ended thereafter.

  DESCRIPTION OF SYMBOLS 1 ... Engine (ENG), 1a ... Output shaft, 2 ... 1st motor generator (1st motor; MG1), 3 ... 2nd motor generator (2nd motor; MG2), 4 ... Power split mechanism, 4a ... Input shaft 5 ... Drive shaft 6 ... Sun gear (second rotating element) 7 ... Ring gear (third rotating element) 8 ... Carrier (first rotating element) 9 ... One-way brake (braking means) 20 ... Speed change Mechanism (transmission means), 24 ... Electronic control unit (ECU), Ve ... Hybrid vehicle.

Claims (1)

A first rotating element to which the engine is connected; a second rotating element to which the first motor is connected; and a power split mechanism that performs a differential action by a third rotating element to which the drive shaft and the second motor are connected; In a control apparatus for a hybrid vehicle, comprising: a braking mechanism that selectively stops rotation of an engine output shaft and the first rotating element; and a speed change means that changes the output torque of the second motor and transmits the output torque to the drive shaft. ,
The engine is started when the hybrid vehicle is traveling at a predetermined vehicle speed by the output torque of both the first motor and the second motor in a state where the rotation of the output shaft is stopped by the braking mechanism. Is configured to execute control for starting the engine by setting a gear ratio in the transmission means so that an output torque of the second motor corresponding to the vehicle speed is relatively large. A hybrid vehicle control device.

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